Maximal exercise oxygen pulse as a predictor of mortality among male veterans referred for exercise testing.

PubMed

Oliveira, Ricardo B; Myers, Jonathan; Araújo, Claudio Gil S; Abella, Joshua; Mandic, Sandra; Froelicher, Victor

2009-06-01

Maximal oxygen pulse (O(2) pulse) mirrors the stroke volume response to exercise, and should therefore be a strong predictor of mortality. Limited and conflicting data are, however, available on this issue. Nine hundred forty-eight participants, classified as those with cardiopulmonary disease (CPD) and those without (non-CPD), underwent cardiopulmonary exercise testing (CPX) for clinical reasons between 1993 and 2003. The ability of maximal O(2) pulse and maximal oxygen uptake (peak VO(2)) to predict mortality was investigated using proportional hazards and Akaike information criterion analyses. All-cause mortality was the endpoint. Over a mean follow-up of 6.3+/-3.2 years, there were 126 deaths. Maximal O(2) pulse, expressed in either absolute or relative to age-predicted terms, and peak VO(2) were significant and independent predictors of mortality in those with and without CPD (P<0.04). Akaike information criterion analysis revealed that the model including both maximal O(2) pulse and peak VO(2) had the highest accuracy for predicting mortality. The optimal cut-points for O(2) pulse and peak VO(2) (<12; > or =12 ml/beat and <16; > or =16 ml/(kg.min) respectively) were established by the area under the receiver-operating-characteristic curve. The relative risks of mortality were 3.4 and 2.2 (CPD and non-CPD, respectively) among participants with both maximal O(2) pulse and peak VO(2) responses below these cut-points compared with participants with both responses above these cut-points. These results indicate that maximal O(2) pulse is a significant predictor of mortality in patients with and without CPD. The addition of absolute and relative O(2) pulse data provides complementary information for risk-stratifying heterogeneous participants referred for CPX and should be routinely included in the CPX report.

Impact of left ventricular assist device speed adjustment on exercise tolerance and markers of wall stress.

PubMed

Hayward, Christopher S; Salamonsen, Robert; Keogh, Anne M; Woodard, John; Ayre, Peter; Prichard, Roslyn; Kotlyar, Eugene; Macdonald, Peter S; Jansz, Paul; Spratt, Phillip

2015-09-01

Left ventricular assist devices are crucial in rehabilitation of patients with end-stage heart failure. Whether cardiopulmonary function is enhanced with higher pump output is unknown. 10 patients (aged 39±16 years, mean±SD) underwent monitored adjustment of pump speed to determine minimum safe low speed and maximum safe high speed at rest. Patients were then randomized to these speed settings and underwent three 6-minute walk tests (6MWT) and symptom-limited cardiopulmonary stress tests (CPX) on separate days. Pump speed settings (low, normal and high) resulted in significantly different resting pump flows of 4.43±0.6, 5.03±0.94, and 5.72±1.2 l/min (P<.001). There was a significant enhancement of pump flows (greater at higher speed settings) with exercise (P<0.05). Increased pump speed was associated with a trend to increased 6MWT distance (P=.10); and CPX exercise time (p=.27). Maximum workload achieved and peak oxygen consumption were significantly different comparing low to high pump speed settings only (P<.05). N-terminal-pro-B-type natriuretic peptide release was significantly reduced at higher pump speed with exercise (P<.01). We have found that alteration of pump speed setting resulted in significant variation in estimated pump flow. The high-speed setting was associated with lower natriuretic hormone release consistent with lower myocardial wall stress. This did not, however, improve exercise tolerance.

Effect of physical training on the recovery of acute exercise, among patients with cardiovascular disease.

PubMed

García-Saldivia, Marianna; Ilarraza-Lomelí, Hermes; Myers, Jonathan; Lara, Jorge; Bueno, Leopoldo

Physical training programs (PTP) have shown several beneficial effects for patients with cardiovascular disease (CVD), particularly by increasing survival and quality of life. Physiological response during the effort and recovery phases of an exercise testing, is one of the strongest prognostic markers among patients with CVD. A reasonable mechanism that explains those training effects on survival is through the adaptations seen on heart rate recovery (HRR) and oxygen uptake kinetics at the post-exertional phase (RVO 2 ). Compare the HRR and RVO 2 values before and after a PTP in patients with CVD. We studied a cohort of patients included in a cardiac rehabilitation program, whom performed a cardiopulmonary exercise testing (CPX). Then, risk stratification and an individualized exercise training program were performed. The exercise training program included 20 sessions of aerobic exercise, 30min a day, five times a week, at moderate intensity. Finally, a second CPX was performed. A total of 215 patients were included. Peak oxygen uptake values rose 2.2±5.2ml/kg/min (p<0.001), HRR increased 1.6±10bpm (p<0.05) and RVO 2 improved -21±98s (p<0.001). A post-hoc analysis show that the percentage of maximum heart rate remained statistically associated with HRR increment. Furthermore, diabetes and sedentarism were strongly related to RVO 2 improvement. No correlation between HRR and RVO 2 was found (R 2 =0.002). Physical exercise was associated with a beneficial effect on HRR and RVO 2 . Nevertheless, both variables were statistically unrelated. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. All rights reserved.

Importance of compensatory heart rate increase during myocardial ischemia to preserve appropriate oxygen kinetics.

PubMed

Yoshida, Sadamitsu; Adachi, Hitoshi; Murata, Makoto; Tomono, Junichi; Oshima, Shigeru; Kurabayashi, Masahiko

2017-09-01

Myocardial ischemia induces cardiac dysfunction, resulting in insufficient oxygen supply to peripheral tissues and mismatched energy production during exercise. To relieve the insufficient oxygen supply, heart rate (HR) response is augmented; however, beta-adrenergic receptor blockers (BB) restrict HR response. Although BB are essential drugs for angina pectoris, the effect of BB on exercise tolerance in patients with angina has not been studied. The aim of this study was to clarify the importance of HR augmentation to preserve exercise tolerance in patients with angina pectoris. Forty-two subjects who underwent cardiopulmonary exercise testing (CPX) to detect myocardial ischemia were enrolled. CPX was performed until exhaustion or onset of significant myocardial ischemia using a ramp protocol. Subjects were assigned to three groups (Group A: with ST depression during CPX with significant coronary stenosis and taking BB; Group B: with ST depression and not taking BB; Group C: without ST depression and not taking BB). HR response to exercise was evaluated during the following two periods: below and above ischemic threshold (IT). In Group C, it was evaluated during the first 2min and the last 2min of a ramp exercise. No significant differences were observed among the three groups with regard to patients' basic characteristics. Below IT, there were no differences in oxygen pulse/watt (O 2 pulse increasing rate), HR/watt (ΔHR/ΔWR), and ΔV˙O 2 /ΔWR. Above IT, O 2 pulse increasing rate was greater in Group A than in Group B. ΔHR/ΔWR was smaller in Group A than in Group B. ΔV˙O 2 /ΔWR became smaller in Group A than in Group B. There was no difference in anaerobic threshold, and peak V˙O 2 was smaller in Group A than in Group B. Restriction of HR response by a BB is shown to be one of the important factors in diminished exercise tolerance. Copyright © 2016 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Influence of stroke volume and exercise tolerance on peak oxygen pulse in patients with and without beta-adrenergic receptor blockers in patients with heart disease.

PubMed

Murata, Makoto; Adachi, Hitoshi; Oshima, Shigeru; Kurabayashi, Masahiko

2017-01-01

In a given individual, a consistent relationship exists between oxygen uptake (V˙O 2 ) and heart rate (HR) during exercise. The quotient of V˙O 2 and HR (V˙O 2 /HR) is called the oxygen pulse (O 2 pulse), and its value is dependent on stroke volume (SV). However, it is difficult to believe that the O 2 pulse would indicate the SV when HR has been modified as with the use of beta-adrenergic receptor blockers (BB). Until now, the effect of BB on peak O 2 pulse has not been precisely studied. We tried to clarify the effect of BB on the relationship between O 2 pulse and SV. Of 699 consecutive heart disease subjects who performed cardiopulmonary exercise tests (CPX) from 2012 to 2014, we enrolled 430 subjects who had sinus rhythm and could perform CPX until exhaustion. One hundred and fifty-seven subjects were taking BB. SV was evaluated during CPX using impedance cardiography, and we compared the peak O 2 pulse with peak SV between patients without BB (Group A) and with BB (Group B). The HRs at rest and peak exercise in Group A were greater than those in Group B (74.4±13.0/min vs. 71.8±11.3/min, p<0.01, 134.9±21.7/min vs. 124.9±23.6/min, p<0.01, respectively). The regression line of the peak O 2 pulse against the peak SV was steeper in Group B than in Group A. When we divided the patients into two groups according to the average values of the peak SV and peak V˙O 2 , O 2 pulse/SV ratio in Group B above the average was greater than that in Group A, whereas it was similar in the two groups that were below average. We found that the increase in the O 2 pulse was disproportionately greater than the SV that was measured by impedance cardiography when a BB was used in patients with preserved SV and exercise tolerance. Copyright © 2016. Published by Elsevier Ltd.

Oxygen uptake efficiency slope as a useful measure of cardiorespiratory fitness in morbidly obese women

PubMed Central

Felismino, Amanda; Corte, Renata Cristina; Silva, Eliane

2017-01-01

Cardiopulmonary assessment through oxygen uptake efficiency slope (OUES) data has shown encouraging results, revealing that we can obtain important clinical information about functional status. Until now, the use of OUES has not been established as a measure of cardiorespiratory capacity in an obese adult population, only in cardiac and pulmonary diseases or pediatric patients. The aim of this study was to characterize submaximal and maximal levels of OUES in a sample of morbidly obese women and analyze its relationship with traditional measures of cardiorespiratory fitness, anthropometry and pulmonary function. Thirty-three morbidly obese women (age 39.1 ± 9.2 years) performed Cardiopulmonary Exercise Testing (CPX) on a treadmill using the ramp protocol. In addition, anthropometric measurements and pulmonary function were also evaluated. Maximal and submaximal OUES were measured, being calculated from data obtained in the first 50% (OUES50%) and 75% (OUES75%) of total CPX duration. In one-way ANOVA analysis, OUES did not significantly differ between the three different exercise intensities, as observed through a Bland-Altman concordance of 58.9 mL/min/log(L/min) between OUES75% and OUES100%, and 0.49 mL/kg/min/log(l/min) between OUES/kg75% and OUES/kg100%. A strong positive correlation between the maximal (r = 0.79) and submaximal (r = 0.81) OUES/kg with oxygen consumption at peak exercise (VO2peak) and ventilatory anaerobic threshold (VO2VAT) was observed, and a moderate negative correlation with hip circumference (r = -0.46) and body adiposity index (r = -0.50) was also verified. There was no significant difference between maximal and submaximal OUES, showing strong correlations with each other and oxygen consumption (peak and VAT). These results indicate that OUES can be a useful parameter which could be used as a cardiopulmonary fitness index in subjects with severe limitations to perform CPX, as for morbidly obese women. PMID:28384329

Oxygen uptake efficiency slope as a useful measure of cardiorespiratory fitness in morbidly obese women.

PubMed

Onofre, Tatiana; Oliver, Nicole; Carlos, Renata; Felismino, Amanda; Corte, Renata Cristina; Silva, Eliane; Bruno, Selma

2017-01-01

Cardiopulmonary assessment through oxygen uptake efficiency slope (OUES) data has shown encouraging results, revealing that we can obtain important clinical information about functional status. Until now, the use of OUES has not been established as a measure of cardiorespiratory capacity in an obese adult population, only in cardiac and pulmonary diseases or pediatric patients. The aim of this study was to characterize submaximal and maximal levels of OUES in a sample of morbidly obese women and analyze its relationship with traditional measures of cardiorespiratory fitness, anthropometry and pulmonary function. Thirty-three morbidly obese women (age 39.1 ± 9.2 years) performed Cardiopulmonary Exercise Testing (CPX) on a treadmill using the ramp protocol. In addition, anthropometric measurements and pulmonary function were also evaluated. Maximal and submaximal OUES were measured, being calculated from data obtained in the first 50% (OUES50%) and 75% (OUES75%) of total CPX duration. In one-way ANOVA analysis, OUES did not significantly differ between the three different exercise intensities, as observed through a Bland-Altman concordance of 58.9 mL/min/log(L/min) between OUES75% and OUES100%, and 0.49 mL/kg/min/log(l/min) between OUES/kg75% and OUES/kg100%. A strong positive correlation between the maximal (r = 0.79) and submaximal (r = 0.81) OUES/kg with oxygen consumption at peak exercise (VO2peak) and ventilatory anaerobic threshold (VO2VAT) was observed, and a moderate negative correlation with hip circumference (r = -0.46) and body adiposity index (r = -0.50) was also verified. There was no significant difference between maximal and submaximal OUES, showing strong correlations with each other and oxygen consumption (peak and VAT). These results indicate that OUES can be a useful parameter which could be used as a cardiopulmonary fitness index in subjects with severe limitations to perform CPX, as for morbidly obese women.

Effect of rhBMP-2 on tibial plateau fractures in a canine model.

PubMed

Schaefer, Susan L; Lu, Yan; Seeherman, Howard; Li, X Jian; Lopez, Mandi J; Markel, Mark D

2009-04-01

This study was to determine the efficacy of recombinant human bone morphogenetic protien-2 (rhBMP-2)/calcium phosphate matrix (CPX) paste to accelerate healing in a canine articular fracture model with associated subchondral defect. rhBMP-2/CPX (BMP), CPX alone (CPX) or autogenous bone graft (ABG) was administered to a canine articular tibial plateau osteotomy with a subchondral defect in each of 21 female dogs. The unoperated contralateral limbs served as controls. Ground reaction forces, synovial fluid, radiographic changes, mechanical testing, bone density, and histology of bone and synovium were analyzed at 6 weeks after surgery. Radiographic analysis demonstrated that the BMP and CPX groups showed improved bony healing compared to the ABG group at week 6. Histomorphometric analysis demonstrated that the BMP group had significantly increased trabecular bone volume compared to the CPX and ABG groups. Mechanical testing revealed that the BMP group had significantly greater maximum failure loads than the ABG group. Histological analysis demonstrated that the BMP group had significantly less sub-synovial inflammation than CPX group. This study demonstrated that rhBMP-2/CPX accelerated healing of articular fractures with subchondral defect compared to ABG in most of the parameters evaluated, and had less subsynovial inflammation than the CPX alone in a canine model.

Does feedback matter? Practice-based learning for medical students after a multi-institutional clinical performance examination.

PubMed

Srinivasan, Malathi; Hauer, Karen E; Der-Martirosian, Claudia; Wilkes, Michael; Gesundheit, Neil

2007-09-01

Achieving competence in 'practice-based learning' implies that doctors can accurately self- assess their clinical skills to identify behaviours that need improvement. This study examines the impact of receiving feedback via performance benchmarks on medical students' self-assessment after a clinical performance examination (CPX). The authors developed a practice-based learning exercise at 3 institutions following a required 8-station CPX for medical students at the end of Year 3. Standardised patients (SPs) scored students after each station using checklists developed by experts. Students assessed their own performance immediately after the CPX (Phase 1). One month later, students watched their videotaped performance and reassessed (Phase 2). Some students received performance benchmarks (their scores, plus normative class data) before the video review. Pearson's correlations between self-ratings and SP ratings were calculated for overall performance and specific skill areas (history taking, physical examination, doctor-patient communication) for Phase 1 and Phase 2. The 2 correlations were then compared for each student group (i.e. those who received and those who did not receive feedback). A total of 280 students completed both study phases. Mean CPX scores ranged from 51% to 71% of items correct overall and for each skill area. Phase 1 self-assessment correlated weakly with SP ratings of student performance (r = 0.01-0.16). Without feedback, Phase 2 correlations remained weak (r = 0.13-0.18; n = 109). With feedback, Phase 2 correlations improved significantly (r = 0.26-0.47; n = 171). Low-performing students showed the greatest improvement after receiving feedback. The accuracy of student self-assessment was poor after a CPX, but improved significantly with performance feedback (scores and benchmarks). Videotape review alone (without feedback) did not improve self-assessment accuracy. Practice-based learning exercises that incorporate feedback to medical students hold promise to improve self-assessment skills.

Diagnostic value of the six-minute walk test (6MWT) in grown-up congenital heart disease (GUCH): Comparison with clinical status and functional exercise capacity.

PubMed

Kehmeier, Eva S; Sommer, Margot H; Galonska, Anika; Zeus, Tobias; Verde, Pablo; Kelm, Malte

2016-01-15

Exercise testing for the assessment of functional capacity plays an important role in long-term follow-up of GUCH patients. CPX is the favored modality for decision-making recommended in the current guidelines. In contrast to this complex method, the 6 MWT is a simple, easy-to-perform, safe, and commonly available exercise test. Although well-established in various cardiopulmonary diseases, the diagnostic impact of the 6 MWT in GUCH patients is not known so far. 102 GUCH patients were evaluated by 6 MWT and CPX simultaneously. Clinical symptoms were assessed, according to the NYHA classification. Additionally, an echocardiography study, and selected cardiac blood tests (N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive Troponin T) were performed. Ranges of six-minute walk distance (6 MWD) and peak oxygen consumption (peakVO2) were 116-765 m and 6.4-36.2 ml/kg/min, respectively. 6 MWD and peakVO2 showed a close correlation (r=0.72, 95% CI, 0.63 to 0.79). Patients with a peakVO2 of ≤ 15.5 ml/kg/min were excellently identified by 6 MWT (c-value=0.82). A cut-off value of 482 m was optimal to predict reduced peakVO2. In multivariate regression analysis, 6 MWD and NYHA class were identified as relevant predictors of peakVO2. In subgroup analysis, Eisenmenger patients achieved the shortest 6 MWD (280, SD 178 m). In our study population of GUCH patients, the 6 MWD shows a close correlation to peakVO2, and an excellent prediction of reduced peakVO2. Thus, it seems to be an easy-to-perform and reliable screening parameter to evaluate functional capacity of these patients (Controlled Clinical Trials number, NCT02193243). Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Abnormal end-tidal PO(2) and PCO(2) at the anaerobic threshold correlate well with impaired exercise gas exchange in patients with left ventricular dysfunction.

PubMed

Kano, Hiroto; Koike, Akira; Hoshimoto-Iwamoto, Masayo; Nagayama, Osamu; Sakurada, Koji; Suzuki, Takeya; Tsuneoka, Hidekazu; Sawada, Hitoshi; Aizawa, Tadanori; Wasserman, Karlman

2012-01-01

The aim of the present study was to compare the end-tidal O(2) pressure (PETO(2)) to end-tidal CO(2) pressure (PETCO(2)) in cardiac patients during rest and during 2 states of exercise: at anaerobic threshold (AT) and at peak. The purpose was to see which metabolic state, PETO(2) or PETCO(2), best correlated with exercise limitation. Thirty-eight patients with left ventricular (LV) ejection fraction <40% underwent cardiopulmonary exercise testing (CPX). PETO(2) and PETCO(2) were measured during CPX, along with peak O(2) uptake (VO(2)), AT, slope of the increase in ventilation (VE) relative to the increase in CO(2) output (VCO(2)) (VE vs. VCO(2) slope), and the ratio of the increase in VO(2) to the increase in work rate (ΔVO(2)/ΔWR). Both PETO(2) and PETCO(2) measured at AT were best correlated with peakVO(2), AT, ΔVO(2)/ΔWR and VE vs. VCO(2) slope. PETO(2) at AT correlated with reduced peak VO(2) (r=-0.60), reduced AT (r=-0.52), reduced ΔVO(2)/ΔWR (r=-0.55) and increased VE vs. VCO(2) slope (r=0.74). PETCO(2) at AT correlated with reduced peak VO(2) (r=0.67), reduced AT (r=0.61), reduced ΔVO(2)/ΔWR (r=0.58) and increased VE vs. VCO(2) slope (r=-0.80). PETCO(2) and PETO(2) at AT correlated with peak VO(2), AT and ΔVO(2)/ΔWR, but best correlated with increased VE vs. VCO(2) slope. PETO(2) and PETCO(2) at AT can be used as a prime index of impaired cardiopulmonary function during exercise in patients with LV failure.

The CpxRA two-component system is essential for Citrobacter rodentium virulence.

PubMed

Thomassin, Jenny-Lee; Giannakopoulou, Natalia; Zhu, Lei; Gross, Jeremy; Salmon, Kristiana; Leclerc, Jean-Mathieu; Daigle, France; Le Moual, Hervé; Gruenheid, Samantha

2015-05-01

Citrobacter rodentium is a murine intestinal pathogen used as a model for the foodborne human pathogens enterohemorrhagic Escherichia coli and enteropathogenic E. coli. During infection, these pathogens use two-component signal transduction systems to detect and adapt to changing environmental conditions. In E. coli, the CpxRA two-component signal transduction system responds to envelope stress by modulating the expression of a myriad of genes. Quantitative real-time PCR showed that cpxRA was expressed in the colon of C57BL/6J mice infected with C. rodentium. To determine whether CpxRA plays a role during C. rodentium infection, a cpxRA deletion strain was generated and found to have a colonization defect during infection. This defect was independent of an altered growth rate or a defective type III secretion system, and single-copy chromosomal complementation of cpxRA restored virulence. The C. rodentium strains were then tested in C3H/HeJ mice, a lethal intestinal infection model. Mice infected with the ΔcpxRA strain survived infection, whereas mice infected with the wild-type or complemented strains succumbed to infection. Furthermore, we found that the cpxRA expression level was higher during early infection than at a later time point. Taken together, these data demonstrate that the CpxRA two-component signal transduction system is essential for the in vivo virulence of C. rodentium. In addition, these data suggest that fine-tuned cpxRA expression is important for infection. This is the first study that identifies a C. rodentium two-component transduction system required for pathogenesis. This study further indicates that CpxRA is an interesting target for therapeutics against enteric pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Determination of anaerobic threshold through heart rate and near infrared spectroscopy in elderly healthy men.

PubMed

Reis, Michel S; Berton, Danilo C; Arena, Ross; Catai, Aparecida M; Neder, José A; Borghi-Silva, Audrey

2013-01-01

Aging leads to low functional capacity and this can be reversed by safe and adequate exercise prescription. The aim of this study was to identify the anaerobic threshold (AT) obtained from the V-slope method as well as visual inspection of oxyhemoglobin ( O2Hb) and deoxyhemoglobin (HHb) curves and compare findings with the heteroscedastic (HS) method applied to carbon dioxide production ( CO2), heart rate (HR), and HHb data in healthy elderly men. A secondary aim was to assess the degree of agreement between methods for AT determination. Fourteen healthy men (61.4±6.3 years) underwent cardiopulmonary exercise testing (CPX) on a cycle ergometer until physical exhaustion. Biological signals collected during CPX included: ventilatory and metabolic variables; spectroscopy quasi-infrared rays - NIRS; and HR through a cardio-frequency meter. We observed temporal equivalence and similar values of power (W), absolute oxygen consumption (O2 - mL/min), relative O2 ( mL.Kg - 1.min -1), and HR at AT by the detection methods performed. In addition, by the Bland-Altman plot, HR confirmed good agreement between the methods with biases between -1.3 and 3.5 beats per minute. (i) all detection methods were sensitive in identifying AT, including the HS applied to HR and (ii) the methods showed a good correlation in the identification of AT. Thus, these results support HR as valid and readily available parameter in determining AT in healthy elderly men.

Incremental value of Veterans Specific Activity Questionnaire and the YMCA-step test for the assessment of cardiorespiratory fitness in population-based studies.

PubMed

Teren, Andrej; Zachariae, Silke; Beutner, Frank; Ubrich, Romy; Sandri, Marcus; Engel, Christoph; Löffler, Markus; Gielen, Stephan

2016-07-01

Cardiorespiratory fitness is a well-established independent predictor of cardiovascular health. However, the relevance of alternative exercise and non-exercise tests for cardiorespiratory fitness assessment in large cohorts has not been studied in detail. We aimed to evaluate the YMCA-step test and the Veterans Specific Activity Questionnaire (VSAQ) for the estimation of cardiorespiratory fitness in the general population. One hundred and five subjects answered the VSAQ, performed the YMCA-step test and a maximal cardiopulmonary exercise test (CPX) and gave BORG ratings for both exercise tests (BORGSTEP, BORGCPX). Correlations of peak oxygen uptake on a treadmill (VO2_PEAK) with VSAQ, BORGSTEP, one-minute, post-exercise heartbeat count, and peak oxygen uptake during the step test (VO2_STEP) were determined. Moreover, the incremental values of the questionnaire and the step test in addition to other fitness-related parameters were evaluated using block-wise hierarchical regression analysis. Eighty-six subjects completed the step test according to the protocol. For completers, correlations of VO2_PEAK with the age- and gender-adjusted VSAQ, heartbeat count and VO2_STEP were 0.67, 0.63 and 0.49, respectively. However, using hierarchical regression analysis, age, gender and body mass index already explained 68.8% of the variance of VO2_PEAK, while the additional benefit of VSAQ was rather low (3.4%). The inclusion of BORGSTEP, heartbeat count and VO2_STEP increased R(2) by a further 2.2%, 3.3% and 5.6%, respectively, yielding a total R(2) of 83.3%. Neither VSAQ nor the YMCA-step test contributes sufficiently to the assessment of cardiorespiratory fitness in population-based studies. © The European Society of Cardiology 2015.

Time-scale of minor HIV-1 complex circulating recombinant forms from Central and West Africa.

PubMed

Delatorre, Edson; Bello, Gonzalo

2016-11-16

Several HIV-1 circulating recombinant forms with a complex mosaic structure (CRFs_cpx) circulate in central and western African regions. Here we reconstruct the evolutionary history of some of these complex CRFs (09_cpx, 11_cpx, 13_cpx and 45_cpx) and further investigate the dissemination dynamic of the CRF11_cpx clade by using a Bayesian coalescent-based method. The analysis of two HIV-1 datasets comprising 181 pol (36 CRF09_cpx, 116 CRF11_cpx, 20 CRF13_cpx and 9 CRF45_cpx) and 125 env (12 CRF09_cpx, 67 CRF11_cpx, 17 CRF13_cpx and 29 CRF45_cpx) sequences pointed to quite consistent onset dates for CRF09_cpx (~1966: 1958-1979), CRF11_cpx (~1957: 1950-1966) and CRF13_cpx (~1965: 1958-1973) clades; while some divergence was found for the estimated date of origin of CRF45_cpx clade [pol = 1970 (1964-1976); env = 1960 (1952-1969)]. Phylogeographic reconstructions indicate that the HIV-1 CRF11_cpx clade most probably emerged in Cameroon and from there it was first disseminated to the Central Africa Republic and Chad in the early 1970s and to other central and western African countries from the early 1980s onwards. Demographic reconstructions suggest that the CRF11_cpx epidemic grew between 1960 and 1990 with a median exponential growth rate of 0.27 year -1 , and stabilized after. These results reveal that HIV-1 CRFs_cpx clades have been circulating in Central Africa for a period comparable to other much more prevalent HIV-1 group M lineages. Cameroon was probably the epicenter of dissemination of the CRF11_cpx clade that seems to have experienced a long epidemic growth phase before stabilization. The epidemic growth of the CRF11_cpx clade was roughly comparable to other HIV-1 group M lineages circulating in Central Africa.

Characteristics of patients with a relatively greater minimum VE/VCO2 against peak VO2% and impaired exercise tolerance.

PubMed

Nakade, Taisuke; Adachi, Hitoshi; Murata, Makoto; Oshima, Shigeru

2018-05-14

Cardiopulmonary exercise testing (CPX) is used to evaluate functional capacity and assess prognosis in cardiac patients. Ventilatory efficiency (VE/VCO 2 ) reflects ventilation-perfusion mismatch; the minimum VE/VCO 2 value (minVE/VCO 2 ) is representative of pulmonary arterial blood flow in individuals without pulmonary disease. Usually, minVE/VCO 2 has a strong relationship with the peak oxygen uptake (VO 2 ), but dissociation can occur. Therefore, we investigated the relationship between minVE/VCO 2 and predicted peak VO 2 (peak VO 2 %) and evaluated the parameters associated with a discrepancy between these two parameters. A total of 289 Japanese patients underwent CPX using a cycle ergometer with ramp protocols between 2013 and 2014. Among these, 174 patients with a peak VO 2 % lower than 70% were enrolled. Patients were divided into groups based on their minVE/VCO 2 [Low group: minVE/VCO 2  < mean - SD (38.8-5.6); High group: minVE/VCO 2  > mean + SD (38.8 + 5.6)]. The characteristics and cardiac function at rest, evaluated using echocardiography, were compared between groups. The High group had a significantly lower ejection fraction, stroke volume, and cardiac output, and higher brain natriuretic peptide, tricuspid regurgitation pressure gradient, right ventricular systolic pressure, and peak early diastolic LV filling velocity/peak atrial filling velocity ratio compared with the Low group (p's < 0.01). In addition, the Low group had a significantly higher prevalence of pleural effusion than did the High group (26 vs 11%, p < 0.01). Patients with a relatively greater minVE/VCO 2 in comparison with peak VO 2 had impaired cardiac output as well as restricted pulmonary blood flow increase during exercise, partly due to accumulated pleural effusion.

A connecter-like factor, CacA, links RssB/RpoS and the CpxR/CpxA two-component system in Salmonella

PubMed Central

2012-01-01

Background Bacteria integrate numerous environmental stimuli when generating cellular responses. Increasing numbers of examples describe how one two-component system (TCS) responds to signals detected by the sensor of another TCS. However, the molecular mechanisms underlying this phenomenon remain poorly defined. Results Here, we report a connector-like factor that affects the activity of the CpxR/CpxA two-component system in Salmonella enterica serovar Typhimurium. We isolated a clone that induced the expression of a cpxP-lac gene fusion from a high-copy-number plasmid pool of random Salmonella genomic fragments. A 63-amino acid protein, CacA, was responsible for the CpxA/CpxR-dependent activation of the cpxP gene. The CpxR-activated genes cpxP and spy exhibited approximately 30% and 50% reductions in transcription, respectively, in a clean cacA deletion mutant strain in comparison to wild-type. From 33 response regulator (RR) deletion mutants, we identified that the RssB regulator represses cacA transcription. Substitution mutations in a conserved -10 region harboring the RNA polymerase recognition sequence, which is well conserved with a known RpoS -10 region consensus sequence, rendered the cacA promoter RpoS-independent. The CacA-mediated induction of cpxP transcription was affected in a trxA deletion mutant, which encodes thioredoxin 1, suggesting a role for cysteine thiol-disulfide exchange(s) in CacA-dependent Cpx activation. Conclusions We identified CacA as an activator of the CpxR/CpxA system in the plasmid clone. We propose that CacA may integrate the regulatory status of RssB/RpoS into the CpxR/CpxA system. Future investigations are necessary to thoroughly elucidate how CacA activates the CpxR/CpxA system. PMID:23031642

A connecter-like factor, CacA, links RssB/RpoS and the CpxR/CpxA two-component system in Salmonella.

PubMed

Kato, Akinori; Hayashi, Hironori; Nomura, Wataru; Emori, Haruka; Hagihara, Kei; Utsumi, Ryutaro

2012-10-02

Bacteria integrate numerous environmental stimuli when generating cellular responses. Increasing numbers of examples describe how one two-component system (TCS) responds to signals detected by the sensor of another TCS. However, the molecular mechanisms underlying this phenomenon remain poorly defined. Here, we report a connector-like factor that affects the activity of the CpxR/CpxA two-component system in Salmonella enterica serovar Typhimurium. We isolated a clone that induced the expression of a cpxP-lac gene fusion from a high-copy-number plasmid pool of random Salmonella genomic fragments. A 63-amino acid protein, CacA, was responsible for the CpxA/CpxR-dependent activation of the cpxP gene. The CpxR-activated genes cpxP and spy exhibited approximately 30% and 50% reductions in transcription, respectively, in a clean cacA deletion mutant strain in comparison to wild-type. From 33 response regulator (RR) deletion mutants, we identified that the RssB regulator represses cacA transcription. Substitution mutations in a conserved -10 region harboring the RNA polymerase recognition sequence, which is well conserved with a known RpoS -10 region consensus sequence, rendered the cacA promoter RpoS-independent. The CacA-mediated induction of cpxP transcription was affected in a trxA deletion mutant, which encodes thioredoxin 1, suggesting a role for cysteine thiol-disulfide exchange(s) in CacA-dependent Cpx activation. We identified CacA as an activator of the CpxR/CpxA system in the plasmid clone. We propose that CacA may integrate the regulatory status of RssB/RpoS into the CpxR/CpxA system. Future investigations are necessary to thoroughly elucidate how CacA activates the CpxR/CpxA system.

Effects of a Physical Activity Program on Cardiorespiratory Fitness and Pulmonary Function in Obese Women after Bariatric Surgery: a Pilot Study.

PubMed

Onofre, Tatiana; Carlos, Renata; Oliver, Nicole; Felismino, Amanda; Fialho, Davi; Corte, Renata; da Silva, Eliane Pereira; Godoy, Eudes; Bruno, Selma

2017-08-01

In severely obese individuals, reducing body weight induced by bariatric surgery is able to promote a reduction in comorbidities and improve respiratory symptoms. However, cardiorespiratory fitness (CRF) reflected by peak oxygen uptake (VO 2peak ) may not improve in individuals who remain sedentary post-surgery. The objective of this study was to evaluate the effects of a physical training program on CRF and pulmonary function in obese women after bariatric surgery, and to compare them to a control group. Twelve obese female candidates for bariatric surgery were evaluated in the preoperative, 3 months postoperative (3MPO), and 6 months postoperative (6MPO) periods through anthropometry, spirometry, and cardiopulmonary exercise testing (CPX). In the 3MPO period, patients were divided into control group (CG, n = 6) and intervention group (IG, n = 6). CG received only general guidelines while IG underwent a structured and supervised physical training program involving aerobic and resistance exercises, lasting 12 weeks. All patients had a significant reduction in anthropometric measurements and an increase in lung function after surgery, with no difference between groups. However, only IG presented a significant increase (p < 0.05) in VO 2peak and total CPX duration of 5.9 mL/kg/min (23.8%) and 4.9 min (42.9%), respectively. Applying a physical training program to a group of obese women after 3 months of bariatric surgery could promote a significant increase in CRF only in the trained group, yet also showing that bariatric surgery alone caused an improvement in the lung function of both groups.

Impact of student ethnicity and primary childhood language on communication skill assessment in a clinical performance examination.

PubMed

Fernandez, Alicia; Wang, Frances; Braveman, Melissa; Finkas, Lindsay K; Hauer, Karen E

2007-08-01

Clinical performance examinations (CPX) with standardized patients (SPs) have become a preferred method to assess communication skills in US medical schools. Little is known about how trainees' backgrounds impact CPX performance. The objective of this paper is to examine the impact of student ethnicity, primary childhood language, and experience of diversity on the communication scores of a high-stakes CPX using SPs. This research was designed as an observational study. The participants of this study were third-year medical students at one US medical school. The measurements used in this study were CPX scores from mandatory exam, student demographics and experience with diversity measured by self-report on a survey, and Medical College Admission Test (MCAT) and United States Medical Licensing Examination (USMLE) scores. A total of 135 students participated. Asian and black students scored lower than white students on the communication portion of the CPX by approximately half a standard deviation (Asian, 67.4%; black, 64.4%; white, 69.4%, p < .05). There were no differences by ethnicity on history/physical exam scores. Multivariate analysis controlling for MCAT verbal scores reduced ethnic differences in communication scores (Asian-white mean differences = 1.95, p = 0.02), but Asian-white differences were eliminated only after sequential models included primary childhood language (difference = 0.57, p = 0.6). Even after controlling for English language knowledge as measured in MCAT verbal scores, speaking a primary childhood language other than English is associated with lower CPX communication scores for Asian students. While poorer communication skills cannot be ruled out, SP exams may contain measurement bias associated with differences in childhood language or culture. Caution is indicated when interpreting CPX communication scores among diverse examinees.

The CpxRA two-component system contributes to Legionella pneumophila virulence.

PubMed

Tanner, Jennifer R; Li, Laam; Faucher, Sébastien P; Brassinga, Ann Karen C

2016-06-01

The bacterium Legionella pneumophila is capable of intracellular replication within freshwater protozoa as well as human macrophages, the latter of which results in the serious pneumonia Legionnaires' disease. A primary factor involved in these host cell interactions is the Dot/Icm Type IV secretion system responsible for translocating effector proteins needed to establish and maintain the bacterial replicative niche. Several regulatory factors have been identified to control the expression of the Dot/Icm system and effectors, one of which is the CpxRA two-component system, suggesting essentiality for virulence. In this study, we generated cpxR, cpxA and cpxRA in-frame null mutant strains to further delineate the role of the CpxRA system in bacterial survival and virulence. We found that cpxR is essential for intracellular replication within Acanthamoeba castellanii, but not in U937-derived macrophages. Transcriptome analysis revealed that CpxRA regulates a large number of virulence-associated proteins including Dot/Icm effectors as well as Type II secreted substrates. Furthermore, the cpxR and cpxRA mutant strains were more sodium resistant than the parental strain Lp02, and cpxRA expression reaches maximal levels during postexponential phase. Taken together, our findings suggest the CpxRA system is a key contributor to L. pneumophila virulence in protozoa via virulence factor regulation. © 2016 John Wiley & Sons Ltd.

The Pilates method and cardiorespiratory adaptation to training.

PubMed

Tinoco-Fernández, Maria; Jiménez-Martín, Miguel; Sánchez-Caravaca, M Angeles; Fernández-Pérez, Antonio M; Ramírez-Rodrigo, Jesús; Villaverde-Gutiérrez, Carmen

2016-01-01

Although all authors report beneficial health changes following training based on the Pilates method, no explicit analysis has been performed of its cardiorespiratory effects. The objective of this study was to evaluate possible changes in cardiorespiratory parameters with the Pilates method. A total of 45 university students aged 18-35 years (77.8% female and 22.2% male), who did not routinely practice physical exercise or sports, volunteered for the study and signed informed consent. The Pilates training was conducted over 10 weeks, with three 1-hour sessions per week. Physiological cardiorespiratory responses were assessed using a MasterScreen CPX apparatus. After the 10-week training, statistically significant improvements were observed in mean heart rate (135.4-124.2 beats/min), respiratory exchange ratio (1.1-0.9) and oxygen equivalent (30.7-27.6) values, among other spirometric parameters, in submaximal aerobic testing. These findings indicate that practice of the Pilates method has a positive influence on cardiorespiratory parameters in healthy adults who do not routinely practice physical exercise activities.

A Revised Clinopyroxene-Liquid Geothermometer for Silicic Igneous Systems with Applications to Diffusion Chronometry of the Scaup Lake Rhyolite, Yellowstone Caldera, WY

NASA Astrophysics Data System (ADS)

Brugman, K. K.; Till, C. B.

2017-12-01

Eruption of the Scaup Lake Rhyolite (SCL) ended 220,000 years of dormancy at Yellowstone caldera and initiated the volcano's youngest sequence of eruptions [Christiansen et al., USGS, 2007]. SCL contains 14% phenocrysts (e.g., feldspar, quartz, pyroxene, zircon, Fe-Ti oxides) which exhibit disequilbrium textures that indicate multiple rejuvenation events occurred shortly before eruption. Our previous work using NanoSIMS elemental concentration profiles from clinopyroxene (cpx) intracrystalline zone boundaries as a diffusion dating tool supported our hypothesis that different minerals may not record the same series of pre-eruptive events, with the cpx rims recording older magmatic events (100s of years prior to eruption [Brugman et al., AGU, 2016]) relative to the sanidine rims (< 10 months and 10-40 years prior to eruption [Till et al., Geology, 2015]). However, diffusion chronometry results are highly dependent on the temperature at which the concentration profile was modeled, necessitating the employment of an appropriate geothermometer. SCL cpx is moderately high in FeOtot (Mg# = 56) but very low in Al2O3 (0.53-0.73 wt%), which is similar to cpx from other high-silica systems (e.g., Rattlesnake Tuff cpx = 0.35 wt% Al2O3, Bandelier Tuff cpx = 0.28-0.91 wt% Al2O3, Paektu Millenium eruption pumice cpx = 0.14-1.78 wt% Al2O3, and Pantelleria trachyte cpx = 0.25-0.72 wt% Al2O3). This range of cpx compositions is not well represented in historical experimental data, and thus has not been included in existing cpx and cpx-liquid geothermometer calibrations. These geothermometers predict temperatures >40°C in error of low-Al cpx-saturated experiments. A new regression of Putirka's [RiMG, 2008] cpx-liquid geothermometer calibrated with 64 experimentally-derived cpx of a similar composition to that of SCL increases the geothermometer's dependence on the Mg# and Na+K component of the liquid and decreases its dependence on the Ca+Si component of the liquid. This revised geothermometer reproduces experimental conditions to ±20°C. This updated thermometer returns temperatures for SCL cpx 30°C lower than the Putirka [RiMG, 2008] cpx-liquid geothermometer, thereby increasing the timescales previously reported for SCL cpx, and increasing the difference in timescales recorded by the SCL cpx and sanidine rims.

Prediction of Cardiorespiratory Fitness by the Six-Minute Step Test and Its Association with Muscle Strength and Power in Sedentary Obese and Lean Young Women: A Cross-Sectional Study

PubMed Central

Bonjorno Junior, José Carlos; de Oliveira, Cláudio Ricardo; Luporini, Rafael Luís; Mendes, Renata Gonçalves; Zangrando, Katiany Thais Lopes; Trimer, Renata; Arena, Ross

2015-01-01

Impaired cardiorespiratory fitness (CRF) is a hallmark characteristic in obese and lean sedentary young women. Peak oxygen consumption (VO2peak) prediction from the six-minute step test (6MST) has not been established for sedentary females. It is recognized that lower-limb muscle strength and power play a key role during functional activities. The aim of this study was to investigate cardiorespiratory responses during the 6MST and CPX and to develop a predictive equation to estimate VO2peak in both lean and obese subjects. Additionally we aim to investigate how muscle function impacts functional performance. Lean (LN = 13) and obese (OB = 18) women, aged 20–45, underwent a CPX, two 6MSTs, and isokinetic and isometric knee extensor strength and power evaluations. Regression analysis assessed the ability to predict VO2peak from the 6MST, age and body mass index (BMI). CPX and 6MST main outcomes were compared between LN and OB and correlated with strength and power variables. CRF, functional capacity, and muscle strength and power were lower in the OB compared to LN (<0.05). During the 6MST, LN and OB reached ~90% of predicted maximal heart rate and ~80% of the VO2peak obtained during CPX. BMI, age and number of step cycles (NSC) explained 83% of the total variance in VO2peak. Moderate to strong correlations between VO2peak at CPX and VO2peak at 6MST (r = 0.86), VO2peak at CPX and NSC (r = 0.80), as well as between VO2peak, NSC and muscle strength and power variables were found (p<0.05). These findings indicate the 6MST, BMI and age accurately predict VO2peak in both lean and obese young sedentary women. Muscle strength and power were related to measures of aerobic and functional performance. PMID:26717568

Ciclopirox olamine inhibits mTORC1 signaling by activation of AMPK.

PubMed

Zhou, Hongyu; Shang, Chaowei; Wang, Min; Shen, Tao; Kong, Lingmei; Yu, Chunlei; Ye, Zhennan; Luo, Yan; Liu, Lei; Li, Yan; Huang, Shile

2016-09-15

Ciclopirox olamine (CPX), an off-patent antifungal agent, has recently been identified as a potential anticancer agent. The mammalian target of rapamycin (mTOR) is a central controller of cell growth, proliferation and survival. Little is known about whether and how CPX executes its anticancer action by inhibiting mTOR. Here we show that CPX inhibited the phosphorylation of p70 S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1), two downstream effector molecules of mTOR complex 1 (mTORC1), in a spectrum of human tumor cells, indicating that CPX inhibits mTORC1 signaling. Using rhabdomyosarcoma cells as an experimental model, we found that expression of constitutively active mTOR (E2419K) conferred resistance to CPX inhibition of cell proliferation, suggesting that CPX inhibition of mTORC1 contributed to its anticancer effect. In line with this, treatment with CPX inhibited tumor growth and concurrently suppressed mTORC1 signaling in RD xenografts. Mechanistically, CPX inhibition of mTORC1 was neither via inhibition of IGF-I receptor or phosphoinositide 3-kinase (PI3K), nor by activation of phosphatase and tensin homolog (PTEN). Instead, CPX inhibition of mTORC1 was attributed to activation of AMP-activated protein kinase (AMPK)-tuberous sclerosis complexes (TSC)/raptor pathways. This is supported by the findings that CPX activated AMPK; inhibition of AMPK with Compound C or ectopic expression of dominant negative AMPKα partially prevented CPX from inhibiting mTORC1; silencing TSC2 attenuated CPX inhibition of mTORC1; and CPX also increased AMPK-mediated phosphorylation of raptor (S792). Therefore, the results indicate that CPX exerts the anticancer effect by activating AMPK, resulting in inhibition of mTORC1 signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

Reduced exercise capacity in untreated adults with primary growth hormone resistance (Laron syndrome).

PubMed

Ben-Dov, Issahar; Gaides, Mark; Scheinowitz, Mickey; Wagner, Rivka; Laron, Zvi

2003-12-01

Primary IGF-I deficiency (Laron syndrome, LS) may decrease exercise capacity as a result of a lack of an IGF-I effect on heart, peripheral muscle or lung structure and/or function. Eight patients (six females) who had never received treatment with IGF-I, with mean age of 36 +/- 10 (SD) years (range 21-48), weight 47 +/- 9 kg (31-61), height 126 +/- 12 cm (112-140) and body mass index of 29 +/- 4 kg/m2 (24-34), and 12 age-matched controls, underwent lung function tests and incremental cycling to the limit of tolerance (CPX, MedGraphics). Predicted values for the patients were derived from adult equations based on height. In LS patients, lung function was near normal; vital capacity was 84 +/- 11% of expected (66-103). Peak exercise O2-uptake and the anaerobic threshold were reduced, 57 +/- 20% of predicted and 33 +/- 9% of predicted peak (P = 0.005 vs. controls), despite normal mean exercise breathing reserve. All parameters were normal in the controls. Exercise capacity in untreated adults with LS is significantly reduced. The limitation for most patients was not ventilatory but resulted either from low cardiac output and/or from dysfunction of the peripheral muscles. However, the relative contribution of each of these elements and/or the role of poor fitness needs further study.

Asthenospheric/Lithospheric interaction beneath Lianshan (Subei Basin, Eastern China)

NASA Astrophysics Data System (ADS)

Hao, Yantao; Bonadiman, Costanza; Coltorti, Massimo; Xia, Qunke

2014-05-01

This contribution presents the geochemical characterization of peridotite xenoliths entrained in Cenozoic alkali basalts from Lianshan (Subei Basin, Eastern China). The majority of the samples are lherzolites (lh) subdivided in three groups depending on the modal contents of clinopyroxene (cpx): cpx-poor lh (6

Identification of CpxR as a positive regulator of icm and dot virulence genes of Legionella pneumophila.

PubMed

Gal-Mor, Ohad; Segal, Gil

2003-08-01

To date, 24 Legionella pneumophila genes (icm and dot genes) have been shown to be required for intercellular growth and host cell killing. A previous report indicated that the regulation of these genes is complicated and probably involves several regulatory proteins. In this study, a genetic screen performed in Escherichia coli identified the CpxR response regulator as an activator of the L. pneumophila icmR gene. Construction of an L. pneumophila cpxR insertion mutant showed that the expression of icmR is regulated by CpxR. In addition, a conserved CpxR binding site (GTAAA) was identified in the icmR regulatory region and L. pneumophila His-tagged CpxR protein was shown to bind to the icmR regulatory region using a mobility shift assay. Besides its dramatic effect on the icmR level of expression, the CpxR regulator was also found to affect the expression of the icmV-dotA and icmW-icmX operons, but to a lesser extent. The role of CpxA, the cognate sensor kinase of CpxR, was also examined and its effect on the icmR level of expression was found to be less pronounced than the effect of CpxR. The RpoE sigma factor, which was shown to coregulate genes together with CpxR, was examined as well, but it did not influence icm and dot gene expression. In addition, when the cpxR mutant strain, in which the expression of the icmR gene was dramatically reduced, and the cpxA and rpoE mutant strains were examined for their ability to grow inside Acanthamoeba castellanii and HL-60-derived human macrophages, no intracellular growth defect was observed. This study presents the first evidence for a direct regulator (CpxR) of an icm-dot virulence gene (icmR). The CpxR regulator together with other regulatory factors probably concerts with the expression of icm and dot genes to result in successful infection.

The Escherichia coli Cpx envelope stress response regulates genes of diverse function that impact antibiotic resistance and membrane integrity.

PubMed

Raivio, Tracy L; Leblanc, Shannon K D; Price, Nancy L

2013-06-01

The Cpx envelope stress response mediates adaptation to stresses that cause envelope protein misfolding. Adaptation is partly conferred through increased expression of protein folding and degradation factors. The Cpx response also plays a conserved role in the regulation of virulence determinant expression and impacts antibiotic resistance. We sought to identify adaptive mechanisms that may be involved in these important functions by characterizing changes in the transcriptome of two different Escherichia coli strains when the Cpx response is induced. We show that, while there is considerable strain- and condition-specific variability in the Cpx response, the regulon is enriched for proteins and functions that are inner membrane associated under all conditions. Genes that were changed by Cpx pathway induction under all conditions were involved in a number of cellular functions and included several intergenic regions, suggesting that posttranscriptional regulation is important during Cpx-mediated adaptation. Some Cpx-regulated genes are centrally involved in energetics and play a role in antibiotic resistance. We show that a number of small, uncharacterized envelope proteins are Cpx regulated and at least two of these affect phenotypes associated with membrane integrity. Altogether, our work suggests new mechanisms of Cpx-mediated envelope stress adaptation and antibiotic resistance.

Ciclopirox induces autophagy through reactive oxygen species-mediated activation of JNK signaling pathway

PubMed Central

Zhou, Hongyu; Shen, Tao; Shang, Chaowei; Luo, Yan; Liu, Lei; Yan, Juming; Li, Yan; Huang, Shile

2014-01-01

Ciclopirox olamine (CPX), a fungicide, has been demonstrated as a potential anticancer agent. However, the underlying anticancer mechanism is not well understood. Here, we found that CPX induced autophagy in human rhabdomyosarcoma (Rh30 and RD) cells. It appeared that CPX-induced autophagy was attributed to induction of reactive oxygen species (ROS), as N-acetyl-L-cysteine (NAC), a ROS scavenger and antioxidant, prevented this process. Furthermore, we observed that CPX induced activation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 MAPK, which was also blocked by NAC. However, only inhibition of JNK (with SP600125) or expression of dominant negative c-Jun partially prevented CPX-induced autophagy, indicating that ROS-mediated activation of JNK signaling pathway contributed to CPX-induced autophagy. Of interest, inhibition of autophagy by chloroquine (CQ) enhanced CPX-induced cell death, indicating that CPX-induced autophagy plays a pro-survival role in human rhabdomyosarcoma cells. Our finding suggests that the combination with autophagy inhibitors may be a novel strategy in potentiating the anticancer activity of CPX for treatment of rhabdomyosarcoma. PMID:25294812

Haemophilus parasuis CpxRA two-component system confers bacterial tolerance to environmental stresses and macrolide resistance.

PubMed

Cao, Qi; Feng, Fenfen; Wang, Huan; Xu, Xiaojuan; Chen, Huanchun; Cai, Xuwang; Wang, Xiangru

2018-01-01

Haemophilus parasuis is an opportunistic pathogen localized in the upper respiratory tracts of pigs, its infection begins from bacterial survival under complex conditions, like hyperosmosis, oxidative stress, phagocytosis, and sometimes antibiotics as well. The two-component signal transduction (TCST) system serves as a common stimulus-response mechanism that allows microbes to sense and respond to diverse environmental conditions via a series of phosphorylation reactions. In this study, we investigated the role of TCST system CpxRA in H. parasuis in response to different environmental stimuli by constructing the ΔcpxA and ΔcpxR single deletion mutants as well as the ΔcpxRA double deletion mutant from H. parasuis serotype 4 isolate JS0135. We demonstrated that H. parasuis TCST system CpxRA confers bacterial tolerance to stresses and bactericidal antibiotics. The CpxR was found to play essential roles in mediating oxidative stress, osmotic stresses and alkaline pH stress tolerance, as well as macrolide resistance (i.e. erythromycin), but the CpxA deletion did not decrease bacterial resistance to abovementioned stresses. Moreover, we found via RT-qPCR approach that HAPS_RS00160 and HAPS_RS09425, both encoding multidrug efflux pumps, were significantly decreased in erythromycin challenged ΔcpxR and ΔcpxRA mutants compared with wild-type strain JS0135. These findings characterize the role of the TCST system CpxRA in H. parasuis conferring stress response tolerance and bactericidal resistance, which will deepen our understanding of the pathogenic mechanism in H. parasuis. Copyright © 2017 Elsevier GmbH. All rights reserved.

Effect of humic acid on ciprofloxacin removal by magnetic multifunctional resins

PubMed Central

Wang, Wei; Cheng, Jiade; Jin, Jing; Zhou, Qing; Ma, Yan; Zhao, Qingqing; Li, Aimin

2016-01-01

Background organic matter significantly influences the removal of emerging contaminants in natural water. In this work, the adsorption of ciprofloxacin (CPX) onto a series of magnetic multifunctional resins (GMA10-GMA90) in the presence and absence of humic acid (HA) was conducted to demonstrate the effect of HA. Both hydrophobic and ion exchange interactions contributed to CPX adsorption. Negative charge-assisted hydrogen bonds also participated in the adsorption process, resulting in the high adsorption amount of anionic CPX onto the negatively charged GMA30 under basic solutions. HA could impact CPX adsorption not only as a competitive adsorbate but also as an additional adsorbent. At pH 5.6, the additional adsorption sites provided by adsorbed HA molecules on the resins dominated and thus facilitated the adsorption process. While at pH 10, HA inhibited the adsorption of CPX by directly competing for ion exchange sites and coexisting with CPX in the solution. The ratio of the amount of CPX adsorbed by dissolved HA to that by the resin reached as high as 1.61 for GMA90. The adsorbed HA molecules onto the resins could provide additional adsorption sites for CPX as proven by the enhanced CPX adsorption in HA-preloading systems at pH 5.6. PMID:27464502

Effect of humic acid on ciprofloxacin removal by magnetic multifunctional resins

NASA Astrophysics Data System (ADS)

Wang, Wei; Cheng, Jiade; Jin, Jing; Zhou, Qing; Ma, Yan; Zhao, Qingqing; Li, Aimin

2016-07-01

Background organic matter significantly influences the removal of emerging contaminants in natural water. In this work, the adsorption of ciprofloxacin (CPX) onto a series of magnetic multifunctional resins (GMA10-GMA90) in the presence and absence of humic acid (HA) was conducted to demonstrate the effect of HA. Both hydrophobic and ion exchange interactions contributed to CPX adsorption. Negative charge-assisted hydrogen bonds also participated in the adsorption process, resulting in the high adsorption amount of anionic CPX onto the negatively charged GMA30 under basic solutions. HA could impact CPX adsorption not only as a competitive adsorbate but also as an additional adsorbent. At pH 5.6, the additional adsorption sites provided by adsorbed HA molecules on the resins dominated and thus facilitated the adsorption process. While at pH 10, HA inhibited the adsorption of CPX by directly competing for ion exchange sites and coexisting with CPX in the solution. The ratio of the amount of CPX adsorbed by dissolved HA to that by the resin reached as high as 1.61 for GMA90. The adsorbed HA molecules onto the resins could provide additional adsorption sites for CPX as proven by the enhanced CPX adsorption in HA-preloading systems at pH 5.6.

Lithium elemental and isotopic disequilibrium in minerals from peridotite xenoliths from far-east Russia: Product of recent melt/fluid rock reaction

NASA Astrophysics Data System (ADS)

Rudnick, Roberta L.; Ionov, Dmitri A.

2007-04-01

Lithium concentrations and isotopic compositions of coexisting olivine and clinopyroxene (cpx) in well-characterized peridotite xenoliths from Tok (SE Siberian craton) and samples from two other far-east Russian localities reveal strong elemental and isotopic disequilibria, which correlates with bulk rock composition. Lithium concentrations in cpx from Tok (1-12 ppm) are equal to or significantly greater than those in coexisting olivines (1-5 ppm). The Li-rich cpx show core to rim zoning, indicative of Li infiltration from the grain boundaries. Olivines are generally unzoned, although Li concentrations can vary significantly from grain to grain. ol/cpxD varies from 0.2 to 1.0, which is lower than that expected for equilibrium partitioning ( ol/cpxDeq = 1.1 to 2.0), and reflects preferential Li enrichment in cpx. The Li isotopic compositions of both minerals range far beyond normal mantle δ7Li of ˜ + 4 ± 2. δ7Li cpx (- 0.8 to - 14.6) is systematically lighter than δ7Li of coexisting olivine (- 1.7 to + 11.9), and Δ 7Li ol-cpx varies from 2.8 to 22.9‰. The greatest elemental and isotopic disequilibria occur in the most fertile samples (lherzolites) and may reflect longer equilibration times and/or enhanced melt permeability in the more refractory samples. Collectively, these observations suggest that the peridotite minerals experienced Li addition via diffusion from a grain boundary melt or fluid shortly before or coincident with their entrainment into the host basalt (i.e., within tens of thousands of years, based on published diffusion coefficients for Li in cpx at the temperatures of equilibration). This diffusional ingress of Li generated large kinetic isotopic fractionation, leading to unusually light cpx and heavier olivines. Thus, low δ7Li cpx do not reflect the influence of an exotic mantle component related to crustal recycling.

The Correlation of Adsorption Behavior between Ciprofloxacin Hydrochloride and the Active Sites of Fe-doped MCM-41.

PubMed

Wu, Ying; Tang, Yiming; Li, Laisheng; Liu, Peihong; Li, Xukai; Chen, Weirui; Xue, Ying

2018-01-01

HIGHLIGHTS Fe incorporation significantly accelerated the adsorption of CPX on MCM-41.Fe leaching can be ignored when pH was higher than 4.0.pH played an important role in CPX adsorption on Fe-MCM-41.Co-effect of CPX and metal cations on Fe-MCM-41 was investigated. Fe-MCM-41s with various molar ratios of silicon to iron (20, 40, 80, and 160) were prepared to investigate adsorption properties of ciprofloxacin hydrochloride (CPX) in aqueous solutions. Fe-MCM-41s were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms, and infrared spectroscopy (FT-IR). Effects of silicon-iron ratio, adsorbent dosage, pH, and temperature were conducted to explore the adsorption mechanism of CPX on Fe-MCM-41. The results showed that the introduction of iron facilitated the absorption quantity for CPX from 20.04 to 83.33 mg g -1 at 120 min of reaction time, which was mainly attributed to surface complexation. The promotion of hydrophobic effect, electrostatic interactions, and π-π electron donor-acceptor interaction also played coordinate roles in the adsorption process. The experimental kinetic data followed both the pseudo-second-order and intra-particle diffusion models, while the adsorption isotherm data fit well to Freundlich model at high temperature. Thermodynamic study showed that the adsorption was spontaneous. Under the effect of electrostatic interaction, pH of the solution strongly affected CPX adsorption. Five representative metal cations (Ca, Cu, Ni, Pb, and Cd) were chosen to study the effects on CPX adsorption and their complexation. The inhibiting effect of metal cations on CPX adsorption was sequenced in the order of Cu > Ni > Pb > Cd > Ca, which followed the same order as the complexation stability constants between CPX and cations. The Fe-MCM-41 adsorbent possessed excellent reusability for 4 cycles use, suggesting a potential applicability of Fe-MCM-41 to remove CPX in water.

The Correlation of Adsorption Behavior between Ciprofloxacin Hydrochloride and the Active Sites of Fe-doped MCM-41

PubMed Central

Wu, Ying; Tang, Yiming; Li, Laisheng; Liu, Peihong; Li, Xukai; Chen, Weirui; Xue, Ying

2018-01-01

HIGHLIGHTS Fe incorporation significantly accelerated the adsorption of CPX on MCM-41.Fe leaching can be ignored when pH was higher than 4.0.pH played an important role in CPX adsorption on Fe-MCM-41.Co-effect of CPX and metal cations on Fe-MCM-41 was investigated. Fe-MCM-41s with various molar ratios of silicon to iron (20, 40, 80, and 160) were prepared to investigate adsorption properties of ciprofloxacin hydrochloride (CPX) in aqueous solutions. Fe-MCM-41s were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms, and infrared spectroscopy (FT-IR). Effects of silicon-iron ratio, adsorbent dosage, pH, and temperature were conducted to explore the adsorption mechanism of CPX on Fe-MCM-41. The results showed that the introduction of iron facilitated the absorption quantity for CPX from 20.04 to 83.33 mg g−1 at 120 min of reaction time, which was mainly attributed to surface complexation. The promotion of hydrophobic effect, electrostatic interactions, and π-π electron donor-acceptor interaction also played coordinate roles in the adsorption process. The experimental kinetic data followed both the pseudo-second-order and intra-particle diffusion models, while the adsorption isotherm data fit well to Freundlich model at high temperature. Thermodynamic study showed that the adsorption was spontaneous. Under the effect of electrostatic interaction, pH of the solution strongly affected CPX adsorption. Five representative metal cations (Ca, Cu, Ni, Pb, and Cd) were chosen to study the effects on CPX adsorption and their complexation. The inhibiting effect of metal cations on CPX adsorption was sequenced in the order of Cu > Ni > Pb > Cd > Ca, which followed the same order as the complexation stability constants between CPX and cations. The Fe-MCM-41 adsorbent possessed excellent reusability for 4 cycles use, suggesting a potential applicability of Fe-MCM-41 to remove CPX in water. PMID:29468153

Intercalation of P atoms in Fullerene-like CP x

NASA Astrophysics Data System (ADS)

Gueorguiev, G. K.; Czigány, Zs.; Furlan, A.; Stafström, S.; Hultman, L.

2011-01-01

The energy cost for P atom intercalation and corresponding structural implications during formation of Fullerene-like Phosphorus carbide (FL-CPx) were evaluated within the framework of Density Functional Theory. Single P atom interstitial defects in FL-CPx are energetically feasible and exhibit energy cost of 0.93-1.21 eV, which is comparable to the energy cost for experimentally confirmed tetragon defects and dangling bonds in CPx. A single P atom intercalation event in FL-CPx can increase the inter-sheet distance from 3.39-3.62 Å to 5.81-7.04 Å. These theoretical results are corroborated by Selected Area Electron Diffraction characterization of FL-CPx samples.

A 3' UTR-Derived Small RNA Provides the Regulatory Noncoding Arm of the Inner Membrane Stress Response.

PubMed

Chao, Yanjie; Vogel, Jörg

2016-02-04

Small RNAs (sRNAs) from conserved noncoding genes are crucial regulators in bacterial signaling pathways but have remained elusive in the Cpx response to inner membrane stress. Here we report that an alternative biogenesis pathway releasing the conserved mRNA 3' UTR of stress chaperone CpxP as an ∼60-nt sRNA provides the noncoding arm of the Cpx response. This so-called CpxQ sRNA, generated by general mRNA decay through RNase E, acts as an Hfq-dependent repressor of multiple mRNAs encoding extracytoplasmic proteins. Both CpxQ and the Cpx pathway are required for cell survival under conditions of dissipation of membrane potential. Our discovery of CpxQ illustrates how the conversion of a transcribed 3' UTR into an sRNA doubles the output of a single mRNA to produce two factors with spatially segregated functions during inner membrane stress: a chaperone that targets problematic proteins in the periplasm and a regulatory RNA that dampens their synthesis in the cytosol. Copyright © 2016 Elsevier Inc. All rights reserved.

Mantle Xenoliths from Central and South Vietnam: Petrology and Geochemistry

NASA Astrophysics Data System (ADS)

Hauzenberger, Christoph; Konzett, Juergen; Nguyen, Hoang; Nguyen, Khoi

2014-05-01

Mantle xenoliths, spinel lherzolites and subordinate amounts of spinel harzburgites and pyroxenites, are commonly found in alkali basalts from south-central Vietnam. The basalts are part of widespread Neogene volcanism found in southern China and Indochina regions. Samples from different localities between the cities of Ban Me Thuot and Saigon were recovered. In addition one xenolith sample from an off-shore volcano SE of Ho Chi Minh City in the South China Sea was investigated. The mineral assemblage in most samples consists of the simple lherzolitic mineral assemblage Ol-Opx-Cpx-Sp. The Ol, Cpx and Opx crystals are equigranular while Sp occurs usually as smaller sized intersertal phase or as partly oriented inclusions in Cpx. Cpx II occurs in some samples as recrystallized "spongy rim" around Cpx I. Cpx I has a a very uniform composition between different samples with a typical XMg (=Mg/(Mg+Fe2+) of 0.92 to 0.98, a XNa (=Na/(Na+Ca) of 0.10 to 0.16, a Cr2O3 content of 0.6-0.9 wt. .% and Al2O3 values of c. 6 to 8 wt.%. Cpx II has a lower XNa and Al content as well as higher XMg and Cr content compared to Cpx I. Orthopyroxene typically has a XMg of c. 0.90 to 0.93. The XMg values for Ol differ slightly between different samples but are within 0.84 to 0.94. Spinel grains have a variable composition with XMg from 0.65 to 0.92 and XCr (Cr/Cr+Al+Fe3+) of 0.08 to 0.25. The use of the Cpx-Opx thermometer (BREY & KOEHLER, 1990) and the Al and Cr in Ol thermometer (DE HOOG et al., 2010) allowed to constrain the temperature with 800 to 1100 °C. Trace and rare earth element composition of Cpx was determined by LA-ICPMS. While most Cpx compositions are slightly depleted in LREE, typical for average depleted mantle compositions, some samples are strongly enriched in LREE indicating mantle metasomatic processes. The sample displaying the highest level of LREE enrichment in Cpx has the lowest calculated temperature (T = c. 800°C) and the highest Ni content in olivine (3000 ppm). The variation in LREE as well as LIL element concentration in Cpx from different xenoliths is evidence for the heterogeneous nature of the mantle beneath Indochina. Financial support from the Austrian Academy of Sciences and ASEA-Uninet is gratefully acknowledged. This is a contribution to IGCP557.

A Petrogenetic Evaluation of Clinopyroxene-hosted Melt Inclusions from an Enriched Submarine Lava of the Samoan Hotspot Track: A Phase Equilibria and Diffusion Modeling Study

NASA Astrophysics Data System (ADS)

Adams, J.; Spera, F. J.; Jackson, M. G.; Schmidt, J.

2017-12-01

The Samoan hotspot track hosts lavas that are representative of the Enriched Mantle II (EMII) geochemical signature, long thought to result from incorporation of recycled upper continental crust. Silicic (66-69 wt% SiO2) clinopyroxene (cpx)-hosted melt inclusions (MI) from isotopically enriched lavas from Samoa provide a window into their petrogenetic evolution. Enriched Samoan submarine lava, ALIA-115-18, from Savai'i Island, Samoa contains clinopyroxene (cpx) antecrysts that host uniformly trachydacitic MI's. The cpx's are more radiogenic (87Sr/86Sr=0.720232-0.720830) than the host whole rock (WR) (87Sr/86Sr=0.718592) providing evidence of cpx antecryst-WR disequilibrium (Jackson et al., 2007, 2009). Phase equilibria calculations using the Magma Chamber Simulator (Bohrson et al., 2014) have corroborated a lack of relationship by fractional crystallization (FC) between the antecrysts and WR composition as well as the cpx's and MI's. Cpx thermobarometry reveals cpx antecryst-WR disequilibrium is not a pressure effect but rather reflects cpx crystallization from a more magnesian parental melt (similar to the most mafic WR of the Samoan submarine lavas; SiO2=49 wt%, MgO=9 wt%), different than the ALIA-115-18 WR. The cpx antecrysts (Mg#72-86), and the rest of the antecryst population show a crystallization range of 1-5 kbar. Cpx groundmass phenocrysts (Mg#70-75) are consistent with ALIA-115-18 WR (SiO2=55 wt%, MgO=5 wt%) composition by FC in the 1-5 kbar range. The more mafic parent may represent the magma that mixed with evolved magmas, giving rise to radiogenic ALIA-115-18, and possibly the silicic MI's. Thus, studying the petrogenesis of the MI's is essential to understanding the evolution of EMII. Many cpx antecrysts with MI's are characterized by compositional halos; transects across the halos exhibit major and trace element gradients. Modeling of diffusive exchange (Cottrell et al., 2002) between the MI's and their host lavas, mediated by diffusion through cpx, allows one to constrain post-entrapment timescales. Preliminary results show distinct gradients in Al, Ti, Si, Cr, Sr, Zr, and the REEs. These elements cover a wide range of diffusivities and partition coefficients enabling a detailed timescale study of post-entrapment MI evolution and the petrogenesis of the Samoan lava suite.

Electrochemical oxidation of ciprofloxacin in two different processes: the electron transfer process on the anode surface and the indirect oxidation process in bulk solutions.

PubMed

Shen, Bo; Wen, Xianghua; Korshin, Gregory V

2018-05-14

Herein, the rotating disk electrode technique was used for the first time to investigate the effects of mass-transfer limitations and pH on the electrochemical oxidation of CPX, to determine the kinetics of CPX oxidation and to explore intrinsic mechanisms during the electron transfer process. Firstly, cyclic voltammetry revealed that an obvious irreversible CPX oxidation peak was observed within the potential window from 0.70 to 1.30 V at all pHs. Based on the Levich equation, the electrochemical oxidation of CPX in the electron transfer process was found to be controlled by both diffusion and kinetic processes when pH = 2, 5, 7 and 9; the diffusion coefficient of CPX at pH = 2 was calculated to be 1.5 × 10-7 cm2 s-1. Kinetic analysis indicated that the reaction on the electrode surface was adsorption-controlled compared to a diffusion process; the surface concentration of electroactive species was estimated to be 1.15 × 10-9 mol cm-2, the standard rate constant of the surface reaction was calculated to be 1.37 s-1, and CPX oxidation was validated to be a two-electron transfer process. Finally, a possible CPX oxidation pathway during the electron transfer process was proposed. The electrochemical degradation of CPX on a Ti-based anode was also conducted subsequently to investigate the electrochemical oxidation of CPX in the indirect oxidation process in bulk solutions. The effects of pH and current density were determined and compared to related literature results. The oxidation of CPX at different pHs is believed to be the result of a counterbalance between favorable and unfavorable factors, namely electromigration and side reactions of oxygen evolution, respectively. The effects of current density indicated a diffusion- and reaction-controlled process at low currents followed by a reaction-controlled process at high currents. The results presented in this study provide better understanding of the electrochemical oxidation of CPX and would enable the development of new treatment methods based on electrochemistry.

Sodium alginate/graphene oxide hydrogel beads as permeable reactive barrier material for the remediation of ciprofloxacin-contaminated groundwater.

PubMed

Zhao, Pingping; Yu, Fei; Wang, Ruoyu; Ma, Yao; Wu, Yanqing

2018-06-01

The wide occurrence of antibiotics in groundwater has raised serious concerns due to their impacts on humans and the ecosystem. Most of the research in groundwater remediation focuses on the exploitation of nano-materials. However, nano-materials have several disadvantages such as high production cost, rapid reduction in permeability, disposal problems, and high sensitivity to environmental conditions. To solve these issues, novel sodium alginate/graphene oxide hydrogel beads (GSA) were synthesised and their effectiveness as permeable reactive barrier (PRB) backfill material in the remediation of ciprofloxacin (CPX)-contaminated groundwater was tested. The adsorption of CPX onto GSA followed the pseudo-second-order kinetic model. The isotherm data followed the Freundlich model. The maximum adsorption capacity was 100 mg g -1 at pH 7.0. The adsorption process was sensitive to contact time, initial CPX concentration and ionic strength. However, it was not pH sensitive. Hydrophobic interaction, electrostatic interaction, ion exchange, H-bonding, and pore filling were proposed to be the main adsorption mechanisms. The effects of flow rate, influent CPX concentration, and ionic strength on the performance of PRB were confirmed through flow-through column experiments and by using a chemical non-equilibrium two-site model. Accordingly, a proper PRB was designed based on hydrogeological conditions. Finally, the lifetime and cost of the PRBs were calculated. The results obtained provided concrete evidence that GSA is a promising adsorbent material for PRBs applications in the remediation of CPX-contaminated groundwater. Copyright © 2018 Elsevier Ltd. All rights reserved.

PecS regulates the urate-responsive expression of type 1 fimbriae in Klebsiella pneumoniae CG43.

PubMed

Wang, Zhe-Chong; Liu, Chia-Jui; Huang, Ying-Jung; Wang, Yu-Seng; Peng, Hwei-Ling

2015-12-01

In the Klebsiella pneumoniae CG43 genome, the divergently transcribed genes coding for PecS, the MarR-type transcription factor, and PecM, the drug metabolite transporter, are located between the type 1 and type 3 fimbrial gene clusters. The intergenic sequence pecO between pecS and pecM contains three putative PecS binding sites and a CpxR box. Electrophoretic mobility shift assay revealed that the recombinant PecS and CpxR could specifically bind to the pecO sequence, and the specific interaction of PecS and pecO could be attenuated by urate. The expression of pecS and pecM was negatively regulated by CpxAR and PecS, and was inducible by exogenous urate in the absence of cpxAR. Compared with CG43S3ΔcpxAR, the derived mutants CG43S3ΔcpxARΔpecS and CG43S3ΔcpxARΔpecSΔpecM exerted similar levels of sensitivity to H2O2 or paraquat, but higher levels of mannose-sensitive yeast agglutination activity and FimA production. The promoter activity and transcript levels of fimA in CG43S3ΔcpxAR were also increased by deleting pecS. However, no binding activity between PecS and the fimA promoter could be observed. Nevertheless, PecS deletion could reduce the expression of the global regulator HNS and release the negative effect of HNS on FimA expression. In CG43S3ΔcpxAR, the expression of FimA as well as PecS was inducible by urate, whilst urate-induced FimA expression was inhibited by the deletion of pecS. Taken together, we propose that K. pneumoniae PecS indirectly and negatively regulates the expression of type 1 fimbriae, and the regulation is urate-inducible in the absence of CpxAR.

Preparing and Training for the Full Spectrum of Military Challenges. Insights from the Experiences of China, France, the United Kingdom, India, and Israel

DTIC Science & Technology

2009-01-01

CPCO Centre de Planification et de Conduite des Opérations CPF Centre de Préparation des Forces CPX command post exercise CT collective training CTC...forces presides over the joint staff and commands French forces in the conduct of operations through the Centre de Planification et de Conduite des...i] t is difficult to identify a single concise statement of the government’s foreign policy.”17 The committee instead pointed to the mission state

Diffusion of Water through Olivine and Clinopyroxene: Implications for Melt Inclusion Fidelity

NASA Astrophysics Data System (ADS)

Plank, T. A.; Lloyd, A. S.; Ferriss, E.

2016-12-01

The maximum H2O concentrations measured in olivine-hosted melt inclusions (MIs) from arc tephra fall within a narrow range of 3-5 wt%. A major question is whether this reflects parental water concentrations or diffusive exchange through the host crystal during storage and ascent. Laboratory experiments have shown that water can diffuse through 500 micron olivine in minutes to days at 1100°C. We have tested these predictions with a natural experiment using volatile (H2O, CO2, S) diffusion along melt embayments to constrain ascent rates during the 1974 eruption of Volcan Fuego to 5-8 minutes from 7 km depth [1]. Thus, olivine-hosted MIs may move from their storage region to the surface during some eruptions rapidly enough to retain almost all of their original water. Only the smallest MIs (< 30 microns) will lose any water during such fast ascent, even for the fastest diffusion mechanism through olivine. We have also assessed the potential for clinopyroxene (cpx) to retain water (as H+) during magma ascent. In the same 1974 Fuego deposits, cpx crystals show H-loss on their rims and even from their interiors. Such diffusive loss in 5-8 minutes requires rapid diffusion of H in cpx, comparable to olivine and melt, and consistent with our recent laboratory experiments dehydrating Fe-bearing cpx [2]. Although H-diffusion is dependent on the site occupancy, all sites may lose H rapidly in cpx with Mg# < 92.5. While cpx and olivine may lose H during ascent and degassing, olivine-hosted MIs stand a better chance of retaining water due to the very low partitioning of water in olivine (D 0.001). The most favorable conditions for faithful retention of parental water concentrations involve a) rapid ascent (< hr.) from H2O-undersaturated reservoirs (prior to major water degassing), b) minerals with low partition coefficients for water, c) large crystals (>500 microns) and large melt inclusions (>50 microns), and 4) rapid post-eruptive cooling (< 1min, clast sizes < 1 cm). The rapid diffusion of H through olivine and cpx presents a challenge to MI fidelity, but not necessarily if the above conditions are met. [1] Lloyd et al., 2014, JVGR. [2] Ferriss et al., 2016, AmMin.

CpxRA influences Xenorhabdus nematophila colonization initiation and outgrowth in Steinernema carpocapsae nematodes through regulation of the nil locus.

PubMed

Herbert Tran, Erin E; Andersen, Aaron W; Goodrich-Blair, Heidi

2009-06-01

The gammaproteobacterium Xenorhabdus nematophila mutualistically colonizes an intestinal region of a soil-dwelling nematode and is a blood pathogen of insects. The X. nematophila CpxRA two-component regulatory system is necessary for both of these host interactions (E. Herbert et al., Appl. Environ. Microbiol. 73:7826-7836, 2007). Mutualistic association of X. nematophila with its nematode host consists of two stages: initiation, where a small number of bacterial cells establish themselves in the colonization site, and outgrowth, where these cells grow to fill the space. In this study, we show that the Cpx system is necessary for both of these stages. X. nematophila DeltacpxR1 colonized fewer nematodes than its wild-type parent and did not achieve as high a density as did the wild type within a portion of the colonized nematodes. To test whether the DeltacpxR1 host interaction phenotypes are due to its overexpression of mrxA, encoding the type I pilin subunit protein, we assessed the colonization phenotype of a DeltacpxR1 DeltamrxA1 double mutant. This mutant displayed the same colonization defect as DeltacpxR1, indicating that CpxR negative regulation of mrxA does not play a detectable role in X. nematophila-host interactions. CpxR positively regulates expression of nilA, nilB, and nilC genes necessary for nematode colonization. Here we show that the nematode colonization defect of the DeltacpxR1 mutant is rescued by elevating nil gene expression through mutation of nilR, a negative regulator of nilA, nilB, and nilC. These data suggest that the nematode colonization defect previously observed in DeltacpxR1 is caused, at least in part, by altered regulation of nilA, nilB, and nilC.

Molecular-Level Control of Ciclopirox Olamine Release from Poly(ethylene oxide)-Based Mucoadhesive Buccal Films: Exploration of Structure-Property Relationships with Solid-State NMR.

PubMed

Urbanova, Martina; Gajdosova, Marketa; Steinhart, Miloš; Vetchy, David; Brus, Jiri

2016-05-02

Mucoadhesive buccal films (MBFs) provide an innovative way to facilitate the efficient site-specific delivery of active compounds while simultaneously separating the lesions from the environment of the oral cavity. The structural diversity of these complex multicomponent and mostly multiphase systems as well as an experimental strategy for their structural characterization at molecular scale with atomic resolution were demonstrated using MBFs of ciclopirox olamine (CPX) in a poly(ethylene oxide) (PEO) matrix as a case study. A detailed description of each component of the CPX/PEO films was followed by an analysis of the relationships between each component and the physicochemical properties of the MBFs. Two distinct MBFs were identified by solid-state NMR spectroscopy: (i) at low API (active pharmaceutical ingredient) loading, a nanoheterogeneous solid solution of CPX molecularly dispersed in an amorphous PEO matrix was created; and (ii) at high API loading, a pseudoco-crystalline system containing CPX-2-aminoethanol nanocrystals incorporated into the interlamellar space of a crystalline PEO matrix was revealed. These structural differences were found to be closely related to the mechanical and physicochemical properties of the prepared MBFs. At low API loading, the polymer chains of PEO provided sufficient quantities of binding sites to stabilize the CPX that was molecularly dispersed in the highly amorphous semiflexible polymer matrix. Consequently, the resulting MBFs were soft, with low tensile strength, plasticity, and swelling index, supporting rapid drug release. At high CPX content, however, the active compounds and the polymer chains simultaneously cocrystallized, leaving the CPX to form nanocrystals grown directly inside the spherulites of PEO. Interfacial polymer-drug interactions were thus responsible not only for the considerably enhanced plasticity of the system but also for the exclusive crystallization of CPX in the thermodynamically most stable polymorphic form, Form I, which exhibited reduced dissolution kinetics. The bioavailability of CPX olamine formulated as PEO-based MBFs can thus be effectively controlled by inducing the complete dispersion and/or microsegregation and nanocrystallization of CPX olamine in the polymer matrix. Solid-state NMR spectroscopy is an efficient tool for exploring structure-property relationships in these complex pharmaceutical solids.

Adaptive servo-ventilation to treat central sleep apnea in heart failure with reduced ejection fraction: the Bad Oeynhausen prospective ASV registry.

PubMed

Oldenburg, Olaf; Wellmann, Birgit; Bitter, Thomas; Fox, Henrik; Buchholz, Anika; Freiwald, Eric; Horstkotte, Dieter; Wegscheider, Karl

2018-04-13

Central sleep apnea (CSA) is highly prevalent in heart failure patients with reduced left ventricular ejection fraction (HF-REF). The Bad Oeynhausen Adaptive Servo-ventilation (ASV) registry (NCT01657188) was designed to investigate whether treatment of CSA with ASV improved survival in HF-REF patients; the effects of ASV on symptoms and cardiopulmonary performance were also investigated. From January 2004 to October 2013, the registry prospectively enrolled HF-REF patients [NYHA class ≥ II, left ventricular ejection fraction (LVEF) ≤ 45%] with moderate to severe predominant CSA [apnea-hypopnea index (AHI) ≥ 15/h]. ASV-treated patients were followed up at 3, 6, 12 and 24 months, including natriuretic peptide concentrations, blood gas analyses, echocardiography, 6-min walk distance (6MWD), and cardiopulmonary exercise (CPX) testing. 550 patients were included [age 67.7 ± 10 years, 90% male, 52% in NYHA class ≥ III, LVEF 29.9 ± 8%, AHI 35.4 ± 13.6/h, and time with nocturnal oxygen saturation < 90% (T < 90%) 58 ± 73 min]; ASV was prescribed to 224 patients. Over a median follow-up of 6.6 years, 109 (48.7%) ASV-treated patients and 191 (58.6%) controls died (adjusted Cox modelling hazard ratio of 0.95, 95% confidence interval 0.68-1.24; p = 0.740); older age, lower LVEF, impaired renal function, low sodium concentration, and nocturnal hypoxemia were significant predictors of mortality. Patient reported NYHA functional class improved in the ASV group, but LVEF, CPX, 6MWD, natriuretic peptides and blood gases remained unchanged. Long-term ASV treatment of predominant CSA in HF-REF patients included in our registry had no statistically significant effect on survival. ASV improved HF symptoms, but had no significant effects on exercise capacity, LVEF, natriuretic peptide concentrations or blood gases during follow-up as compared to control patients.

Discovery of coesite and shocked quartz associated with the upper Eocene cpx spherule layer

NASA Technical Reports Server (NTRS)

Liu, S.; Kyte, T.; Glass, B. P.

2002-01-01

At least two major impact ejecta layers have been discovered in upper Eocene strata. The upper layer is the North American microtektite layer. lt consists tektite fragments, microtektites, and shocked mineral grains (e.g., quartz and feldspar with multiple sets of PDFs, coesite and reidite (a high-pressure polymorph of zircon)). The slightly older layer contains clinopyroxene-bearing (cpx) spherules and microtektites associated with an Ir anomaly. The North American tektite layer may be derived from the Chesapeake Bay impact structure, and the cpx spherule layer may from the Popigai impact crater. A cpx spherule layer associated with a positive Ir anomaly was recently found at ODP Site 709, western Indian Ocean. A large sample (Hole 709C, core 31, section 4, 145-150 cm), originally used for a study of interstitial water by shipboard scientists, was acquired for the purpose of recovering a large number of spherules for various petrographic and geochemical studies. A split of the sample (50.35 g) was disaggregated and wet-sieved. More than 17,000 cpx spherules and several hundred microtektites (larger than 125 microns) were recovered from the sample. Rare white opaque grains were observed in the 125-250 micron size fraction after removal of the carbonate component using dilute HCI. Seven of the white opaque grains were X-rayed using a Gandolfi camera and six were found to be coesite (probably mixed with lechatelierite). Eighty translucent colorless grains from the 63-125 micron size fraction were studied with a petrographic microscope. Four of the grains exhibit one to two sets of planar deformation features (PDFs). The only other possible known occurrence of shocked minerals associated with the cpx spherule layer is at Massignano, Italy, where pancake-shaped clay spherules (thought to be diagenetically altered cpx spherules are associated with a positive Ir anomaly and Ni- rich spinel crystals. Shocked quartz grains with multiple sets of PDFs also occur at this site. Until now, unmelted impact ejecta have not been found associated with the cpx spherules at any of the other 20 sites around the world and this is the first time that coesite has been found associated with the cpx spherule layer. The discovery of coesite and shocked quartz associated with the cpx spherules at Site 709 in Indian Ocean is further evidence for the impact origin of the cpx spherule layer. We hope that future discovery of other unmelted minerals from this sample may provide materials to establish constraints on the provenance of this late Eocene ejecta.

The correlation of adsorption behavior between ciprofloxacin hydrochloride and the active sites of Fe-doped MCM-41

NASA Astrophysics Data System (ADS)

Wu, Ying; Tang, Yiming; Li, Laisheng; Liu, Peihong; Li, Xukai; Chen, Weirui; Xue, Ying

2018-02-01

Fe-MCM-41s with various molar ratios of silicon to iron (20, 40, 80 and 160) were prepared to investigate adsorption properties of ciprofloxacin hydrochloride (CPX) in aqueous solutions. Fe-MCM-41s were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms and infrared spectroscopy (FT-IR). Effects of silicon–iron ratio, adsorbent dosage, pH and temperature were conducted to explore the adsorption mechanism of CPX on Fe-MCM-41. The results showed that the introduction of iron facilitated the absorption quantity for CPX from 20.04 to 83.33 mg g-1 at 120 min of reaction time, which was mainly attributed to surface complexation. The promotion of hydrophobic effect, electrostatic interactions and π-π electron donor–acceptor interaction also played coordinate roles in the adsorption process. The experimental kinetic data followed both the pseudo-second-order and intra-particle diffusion models, while the adsorption isotherm data fit well to Freundlich model at high temperature. Thermodynamic study showed that the adsorption was spontaneous. Under the effect of electrostatic interaction, pH of the solution strongly affected CPX adsorption. Five representative metal cations (Ca, Cu, Ni, Pb and Cd) were chosen to study the effects on CPX adsorption and their complexation. The inhibiting effect of metal cations on CPX adsorption was sequenced in the order of Cu > Ni > Pb > Cd > Ca, which followed the same order as the complexation stability constants between CPX and cations. The Fe-MCM-41 adsorbent possessed excellent reusability for 4 cycles use, suggesting a potential applicability of Fe-MCM-41 to remove CPX in water.

OmpA influences Escherichia coli biofilm formation by repressing cellulose production through the CpxRA two-component system.

PubMed

Ma, Qun; Wood, Thomas K

2009-10-01

Previously we discovered that OmpA of Escherichia coli increases biofilm formation on polystyrene surfaces (González Barrios et al., Biotechnol Bioeng, 93:188-200, 2006a). Here we show OmpA influences biofilm formation differently on hydrophobic and hydrophilic surfaces since it represses cellulose production which is hydrophilic. OmpA increased biofilm formation on polystyrene, polypropylene, and polyvinyl surfaces while it decreased biofilm formation on glass surfaces. Sand column assays corroborated that OmpA decreases attachment to hydrophilic surfaces. The ompA mutant formed sticky colonies, and the extracellular polysaccharide that caused stickiness was identified as cellulose. A whole-transcriptome study revealed that OmpA induces the CpxRA two-component signal transduction pathway that responds to membrane stress. CpxA phosphorylates CpxR and results in reduced csgD expression. Reduced CsgD production represses adrA expression and results in reduced cellulose production since CsgD and AdrA are responsible for 3,5-cyclic diguanylic acid and cellulose synthesis. Real-time polymerase chain reaction confirmed csgD and adrA are repressed by OmpA. Biofilm and cellulose assays with double deletion mutants adrA ompA, csgB ompA, and cpxR ompA confirmed OmpA decreased cellulose production and increased biofilm formation on polystyrene surfaces through CpxR and AdrA. Further evidence of the link between OmpA and the CpxRA system was that overproduction of OmpA disrupted the membrane and led to cell lysis. Therefore, OmpA inhibits cellulose production through the CpxRA stress response system, and this reduction in cellulose increases biofilm formation on hydrophobic surfaces.

Histamine H3 receptor antagonists display antischizophrenic activities in rats treated with MK-801.

PubMed

Mahmood, Danish; Akhtar, Mohd; Jahan, Kausar; Goswami, Dipanjan

2016-09-01

Animal models based on N-methyl-d-aspartate receptor blockade have been extensively used for schizophrenia. Ketamine and MK-801 produce behaviors related to schizophrenia and exacerbated symptoms in patients with schizophrenia, which led to the use of PCP (phencyclidine)- and MK-801 (dizocilpine)-treated animals as models for schizophrenia. The study investigated the effect of subchronic dosing (once daily, 7 days) of histamine H3 receptor (H3R) antagonists, ciproxifan (CPX) (3 mg/kg, i.p.), and clobenpropit (CBP) (15 mg/kg, i.p.) on MK-801 (0.2 mg/kg, i.p.)-induced locomotor activity and also measured dopamine and histamine levels in rat's brain homogenates. The study also included clozapine (CLZ) (3.0 mg/kg, i.p.) and chlorpromazine (CPZ) (3.0 mg/kg, i.p.), the atypical and typical antipsychotic, respectively. Atypical and typical antipsychotic was used to serve as clinically relevant reference agents to compare the effects of the H3R antagonists. MK-801 significantly increased horizontal locomotor activity, which was reduced with CPX and CBP. MK-801-induced locomotor hyperactivity attenuated by CPX and CBP was comparable to CLZ and CPZ. MK-801 raised striatal dopamine level, which was reduced in rats pretreated with CPX and CBP. CPZ also significantly lowered striatal dopamine levels, although the decrease was less robust compared to CLZ, CPX, and CBP. MK-801 increased histamine content although to a lesser degree. Subchronic treatment with CPX and CBP exhibited further increased histamine levels in the hypothalamus compared to MK-801 treatment alone. Histamine H3 receptor agonist, R-α methylhistamine (10 mg/kg, i.p.), counteracted the effect of CPX and CBP. The present study shows the positive effects of CPX and CBP on MK-801-induced schizophrenia-like behaviors in rodents.

Identification of a new HIV-1 circulating recombinant form CRF65_cpx strain in Jilin, China.

PubMed

Wang, Jia-Ye; Chen, Xiao-Hong; Shao, Bing; Huo, Qing-Qing; Liu, Si-Yu; Li, Jin; Wang, Fu-Xiang

2018-05-04

This study reported a new HIV-1 circulating recombinant form CRF65_cpx virus isolated from a man who had sex with men (MSM) in Jilin, China. The near full-length genome of this virus was composed of fourteen mosaic gene fragments derived from CRF01_AE, subtype B' (Thai B) and subtype C, highly similar to the CRF65_cpx viruses recently identified in Yunnan and Anhui of China. Phylogenetic tree analysis suggested that this CRF65_cpx strain was not generated among MSM in Jilin, but originated in southern regions of China and spread to Jilin by MSM population. The emergence of CRF65_cpx in Jilin indicated HIV-1 epidemic in this area was more and more complicated and the MSM population has become the important source for generation of new recombinant viruses. Real-time surveillance of new HIV-1 infections among MSM population is quite required.

Deducing Water Concentrations in the Parent Magma of Cumulate Clinopyroxene and Olivine: Implications for a Hydrous Parent Melt of a Primitive Deccan Lava

NASA Astrophysics Data System (ADS)

Seaman, S. J.

2017-12-01

Water concentrations of clinopyroxene megacrysts in the Powai ankaramite flow, located near Mumbai, Deccan province, India, indicate that the parent magma of the flow hosted at least 4.3 wt.% water, an unusually high water concentration for a continental flood basalt magma. The Powai flow hosts clinopyroxene and olivine phenocrysts. Chatterjee and Sheth (2015) showed that phenocrysts in the flow were part of a cumulate layer intruded by basaltic melt at 6 kb and 1230oC, so the phenocrysts record characteristics of the cumulate parent melt. Clinopyroxene phenocrysts are oscillatorily zoned in water, Mg, Fe, and Ca concentrations, and have concentric bands 100-200 microns thick of 10-20 micron diameter melt inclusions. Olivine phenocrysts host only larger isolated melt inclusions. Zones in the cpx phenocrysts where melt inclusion-rich concentric bands occur have higher concentrations of water than inclusion-free zones. Water concentrations of cpx were used to calculate water concentrations in the melt from which the crystals formed using partition coefficients of Hauri et al. (2004). Water concentrations in the parent magma were between 4.3 and 8.2 wt. % based on water concentrations in cpx. Both Mg and Fe are relatively depleted in the water- and melt inclusion-rich zones in cpx, and Ca is enriched in these zones. Oscillatory zoning in cpx may be a result of repeated growth of cpx in water- richer and water-poorer boundary layers where water lowered melt viscosity and enhanced diffusion and crystal growth rates. Water-enhanced growth rates may have resulted in capture of melt inclusions preserved in water-rich cpx zones. Melt inclusions in olivine phenocrysts preserve lower water concentrations ( 1.2 wt. %) than those indicated by water concentration in cpx phenocrysts. This disparity may be evidence of water loss from melt inclusions in olivine (Gaetani et al., 2009) or may indicate that cpx and ol crystals did not crystallize from the same parent at the same time.

CpxR-Dependent Thermoregulation of Serratia marcescens PrtA Metalloprotease Expression and Its Contribution to Bacterial Biofilm Formation.

PubMed

Bruna, Roberto E; Molino, María Victoria; Lazzaro, Martina; Mariscotti, Javier F; García Véscovi, Eleonora

2018-04-15

PrtA is the major secreted metalloprotease of Serratia marcescens Previous reports implicate PrtA in the pathogenic capacity of this bacterium. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug, and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression in Serratia In this work, we demonstrate that PrtA production is derepressed when the bacterial growth temperature decreases from 37°C to 30°C. We show that this thermoregulation occurs at the transcriptional level. We determined that upstream of prtA , there is a conserved motif that is directly recognized by the CpxR transcriptional regulator. This feature is found along Serratia strains irrespective of their isolation source, suggesting an evolutionary conservation of CpxR-dependent regulation of PrtA expression. We found that in S. marcescen s, the CpxAR system is more active at 37°C than at 30°C. In good agreement with these results, in a cpxR mutant background, prtA is derepressed at 37°C, while overexpression of the NlpE lipoprotein, a well-known CpxAR-inducing condition, inhibits PrtA expression, suggesting that the levels of the activated form of CpxR are increased at 37°C over those at 30°C. In addition, we establish that PrtA is involved in the ability of S. marcescens to develop biofilm. In accordance, CpxR influences the biofilm phenotype only when bacteria are grown at 37°C. In sum, our findings shed light on regulatory mechanisms that fine-tune PrtA expression and reveal a novel role for PrtA in the lifestyle of S. marcescens IMPORTANCE We demonstrate that S. marcescens metalloprotease PrtA expression is transcriptionally thermoregulated. While strongly activated below 30°C, its expression is downregulated at 37°C. We found that in S. marcescens , the CpxAR signal transduction system, which responds to envelope stress and bacterial surface adhesion, is activated at 37°C and able to downregulate PrtA expression by direct interaction of CpxR with a binding motif located upstream of the prtA gene. Moreover, we reveal that PrtA expression favors the ability of S. marcescens to develop biofilm, irrespective of the bacterial growth temperature. In this context, thermoregulation along with a highly conserved CpxR-dependent modulation mechanism gives clues about the relevance of PrtA as a factor implicated in the persistence of S. marcescens on abiotic surfaces and in bacterial host colonization capacity. Copyright © 2018 American Society for Microbiology.

Necessity of introducing postencounter note describing history and physical examination at clinical performance examination in Korea.

PubMed

Kim, Jonghoon

2014-06-01

Information gathering ability had been evaluated mainly via checklists in clinical performance examinations (CPX). But, it is not proved yet if students write the information correctly in postencounter note (PN), although they asked questions or performed physical examinations (PE) about the information when they interacted with standardized patients in CPX. This study addressed the necessity of introducing PN to evaluate the ability in CPX. After patient encounters, students were instructed to write the findings of history taking and physical examination that they considered as important information in approaching the patient's problems in PN. PNs were scored using answer keys selected from checklist items, which were considered to be recorded in PN by CPX experts. PNs of six CPX cases from 54 students were analyzed. Correlation coefficients between the key-checklist scores and PN scores of six cases were moderate to high (0.52 to 0.79). However, students frequently neglected some cardinal features of chief complains, pertinent findings of past/social history and PE, and pertinent negative findings of associated symptoms in PNs, which were checked as 'done' in the keys of checklists. It is necessary to introduce PN in CPX to evaluate the students' ability of synthesis and integration of patient information.

Compositional diversity in peridotites as result of a multi-process history: The Pacific-derived Santa Elena ophiolite, northwest Costa Rica

NASA Astrophysics Data System (ADS)

Escuder-Viruete, Javier; Baumgartner, Peter O.; Castillo-Carrión, Mercedes

2015-08-01

The Santa Elena ophiolite (SEO) is an ultramafic nappe of more than 270 km2 overlying a tectonic serpentinite-matrix mélange in northwest Costa Rica. It is mainly composed of Cpx-rich and Cpx-poor harzburgites (~ 2.5 km-thick), with minor lherzolite, dunite and chromitite, as well as intrusive mafic sills and subvertical dikes, which coalesce into an upper Isla Negritos gabbroic sill complex. Minerals and whole-rock features of the Cpx-rich and Cpx-poor harzburgites share features of the abyssal and supra-subduction zone (SSZ) peridotites, respectively. To explain these characteristics two-stages of melting and refertilization processes are required. By means of trace element modeling, the composition of Cpx-rich harzburgites may be reproduced by up to ~ 5-10% melting of a primitive mantle source, and the composition of Cpx-poor harzburgites and dunites by ~ 15-18% melting of an already depleted mantle. Therefore, the Cpx-rich harzburgites can be interpreted as product of first-stage melting and low-degrees of melt-rock interaction in a mid-ocean ridge environment, and the Cpx-poor harzburgites and dunites as the product of second-stage melting and refertilization in a SSZ setting. The mafic sills and the Isla Negrito gabbros are genetically related and can be explained as crystallization from the liquids that were extracted from the lower SSZ mantle levels and emplaced at shallow conditions. The Murciélagos Island basalts are not directly related to the ultramafic and mafic rocks of the SEO. Their E-MORB-like composition is similar to most of the CLIP mafic lavas and suggests a common Caribbean plume-related source. The SEO represents a fragment of Pacific-derived, SSZ oceanic lithosphere emplaced onto the southern North America margin during the late Cretaceous. Because of the predominance of rollback-induced extension during its history, only a limited amount of crustal rocks were formed and preserved in the SEO.

Microstructures and Lattice Preferred Orientations in Experimentally Deformed Granulites

NASA Astrophysics Data System (ADS)

Miao, S.; Zhou, Y.

2017-12-01

We analysed microstructures and lattice preferred orientations (LPO) on experimentally deformed natural granulites in order to understand the relationship between deformation processes and evolving microstructures. The LPO was measured using the scanning electron microscope (SEM)-based electron backscatter diffraction (EBSD) technique. Microstructures were observed by polarized light microscopy and by orientation contrast in the SEM. Natural granulite samples were collected in the Archean lower crust terrane of North China Craton. This granulite is composed of 59% plagioclase (PI) + 21% clinopyroxene (Cpx) +14% orthopyroxene + 5% opaque minerals+1% quartz. The water contents of bulk rocks were in the range 0.10-0.26 wt.%. The average grain size of PI and Cpx were 240 μm and 220 μm, respectively. These samples were deformed in axial compress tests up to 7%-15% shorting at temperatures ranged from 900 ° to 1150 °. Microstructures results in conjunction with some other parameters such as stress exponents indicated that the samples deformed mainly by intragranular microcracking, twinning and dislocation glide with very little recrystallization. The natural sample, without any macroscopic foliation visible, has a significant initial LPO in Cpx corresponding to an "S-type" fabric with the b[010]maximum normal to a foliation plane. PI also has a pre-existing fabric. We compared the LPO of Cpx and PI of experimentally deformed samples with that of undeformed natural samples. It shows that no clear LPO evolution apart from the initial LPO could be attributed to deformation. Even if at a temperature range (eg. above 1100 °) where partial melting occurs, "S-type" fabrics of Cpx have been remained effectively. Deformation in the dislocation creep regime does not alter the initial LPO nor produce a new pattern. This is consistent with previous results, which stated that large strains, at least more than 25% shortening are necessary to overprint a pre-existing LPO in clinopyroxenes.

Voluminous arc dacites as amphibole reaction-boundary liquids

NASA Astrophysics Data System (ADS)

Blatter, Dawnika L.; Sisson, Thomas W.; Hankins, W. Ben

2017-05-01

Dacites dominate the large-volume, explosive eruptions in magmatic arcs, and compositionally similar granodiorites and tonalites constitute the bulk of convergent margin batholiths. Shallow, pre-eruptive storage conditions are well known for many dacitic arc magmas through melt inclusions, Fe-Ti oxides, and experiments, but their potential origins deeper in the crust are not well determined. Accordingly, we report experimental results identifying the P-T-H2O conditions under which hydrous dacitic liquid may segregate from hornblende (hbl)-gabbroic sources either during crystallization-differentiation or partial melting. Two compositions were investigated: (1) MSH-Yn-1 dacite (SiO2: 65 wt%) from Mount St. Helens' voluminous Yn tephra and (2) MSH-Yn-1 + 10% cpx to force saturation with cpx and map a portion of the cpx + melt = hbl peritectic reaction boundary. H2O-undersaturated (3, 6, and 9 wt% H2O) piston cylinder experiments were conducted at pressures, temperatures, and fO2 appropriate for the middle to lower arc crust (400, 700, and 900 MPa, 825-1100 °C, and the Re-ReO2 buffer ≈ Ni-NiO + 2). Results for MSH-Yn-1 indicate near-liquidus equilibrium with a cpx-free hbl-gabbro residue (hbl, plg, magnetite, ± opx, and ilmeno-hematite) with 6-7 wt% dissolved H2O, 925 °C, and 700-900 MPa. Opx disappears down-temperature consistent with the reaction opx + melt = hbl. Cpx-added phase relations are similar in that once 10% cpx crystallizes, multiple saturation is attained with cpx, hbl, and plg, +/- opx, at 6-7 wt% dissolved H2O, 940 °C, and 700-900 MPa. Plg-hbl-cpx saturated liquids diverge from plg-hbl-opx saturated liquids, consistent with the MSH-Yn-1 dacite marking a liquid composition along a peritectic distributary reaction boundary where hbl appears down-temperature as opx + cpx are consumed. The abundance of saturating phases along this distributary peritectic (liquid + hbl + opx + cpx + plg + oxides) reduces the variance, so liquids are restricted to dacite-granodiorite-tonalite compositions. Higher-K dacites than the Yn would also saturate with biotite, further limiting their compositional diversity. Theoretical evaluation of the energetics of peritectic melting of pargasitic amphiboles indicates that melting and crystallization of amphibole occur abruptly, proximal to amphibole's high-temperature stability limit, which causes the system to dwell thermally under the conditions that produce dacitic compositions. This process may account for the compositional homogeneity of dacites, granodiorites, and tonalites in arc settings, but their relative mobility compared to rhyolitic/granitic liquids likely accounts for their greater abundance.

The Growth of Melt Inclusion- and Water-Rich Zones in Clinopyroxene Phenocrysts of the Powai Ankaramite Flow, Deccan Traps, India: Rapid Closed System Oscillatory Mineral Growth

NASA Astrophysics Data System (ADS)

Seaman, S. J.

2015-12-01

Water concentrations were measured and mapped using FTIR spectroscopy in clinopyroxene phenocrysts of the Powai ankaramite flow, located near Mumbai, west of the Western Ghats escarpment of the Deccan province, India. Samples were provided by Dr. Hetu Sheth of the Indian Institute of Technology, Mumbai. Chatterjee and Sheth (2015) showed that phenocrysts in the flow were part of a cumulate layer intruded by high-temperature basaltic melt at ~ 6 kb and ~1230oC. Cpx phenocrysts are euhedral and have concentric bands (100 to 200 microns thick) of fine (10-20 micron diameter) melt inclusions. Cpx bands that host melt inclusions have higher concentrations of water than inclusion-free bands. Water concentrations of cpx and ol were used to calculate water concentrations in the melt from which the crystals formed. Water concentrations in the parent magma were between 4.35 and 8.26 wt. % based on water concentrations in cpx, and between 8.24 and 9.41 wt. % based on those in ol. Both Mg and Fe are relatively depleted in the water- and melt inclusion-rich zones in cpx, and Ca is enriched in these zones. We suggest that oscillatory zoning in cpx is a result of repeated growth of cpx in water-richer and water-poorer boundary layers in which water lowered melt viscosity and enhanced diffusion and crystal growth rates. Water-enhanced growth rates may have resulted in preferential capture of melt inclusions preserved in water-rich cpx zones. Mg was preferentially incorporated into the cpx, causing Ca and water to build up in the boundary layer, and Mg and Fe to become relatively depleted in the boundary layer, as discussed for oscillatorially-zoned minerals by Wang and Merino (1993). Application of the equations for growth of oscillatory zones in crystals given by Wang and Merino (1993) to the growth of cpx crystals in the Powai ankaramite indicate that crystal growth occurred relatively quickly, on the order of days, although the width of the boundary zone, which is uncertain, controls the rate. These results are consistent with Wang and Merino's contention that oscillatory growth zones in crystals can be the result of closed system processes involving advection and diffusion of ionic species into and out of the boundary zone between crystal and melt, and, on a broader scale, suggest that at least this Deccan magma was relatively hydrous.

Phase 2 trial of CPX-351, a fixed 5:1 molar ratio of cytarabine/daunorubicin, vs cytarabine/daunorubicin in older adults with untreated AML

PubMed Central

Cortes, Jorge E.; Hogge, Donna E.; Tallman, Martin S.; Kovacsovics, Tibor J.; Damon, Lloyd E.; Komrokji, Rami; Solomon, Scott R.; Kolitz, Jonathan E.; Cooper, Maureen; Yeager, Andrew M.; Louie, Arthur C.; Feldman, Eric J.

2014-01-01

CPX-351 is a liposomal formulation of cytarabine:daunorubicin designed to deliver synergistic drug ratios to leukemia cells. In this phase 2 study, newly diagnosed older acute myeloid leukemia (AML) patients were randomized 2:1 to first-line CPX-351 or 7+3 treatment. The goal was to determine efficacy and identify patient subgroups that may benefit from CPX-351 treatment. Response rate (complete remission + incomplete remission) was the primary end point, with event-free survival (EFS) and overall survival (OS) as secondary end points. The 126 patients entered were balanced for disease and patient-specific risk factors. Overall, CPX-351 produced higher response rates (66.7% vs 51.2%, P = .07), meeting predefined criteria for success (P < .1). Differences in EFS and OS were not statistically significant. A planned analysis of the secondary AML subgroup demonstrated an improved response rate (57.6% vs 31.6%, P = .06), and prolongation of EFS (hazard ratio [HR] = 0.59, P = .08) and OS (HR = 0.46, P = .01). Recovery from cytopenias was slower after CPX-351 (median days to absolute neutrophil count ≥1000: 36 vs 32; platelets >100 000: 37 vs 28) with more grade 3-4 infections but without increase in infection-related deaths (3.5% vs 7.3%) or 60-day mortality (4.7% vs 14.6%), indicating acceptable safety. These results suggest a clinical benefit with CPX-351, particularly among patients with secondary AML, and provide the rationale for a phase 3 trial currently underway in newly diagnosed secondary AML patients. This study is registered at Clinicaltrials.gov as #NCT00788892. PMID:24687088

Trace Element Partitioning Between low-Ca Pyroxene and Ultracalcic Liquids.

NASA Astrophysics Data System (ADS)

Pertermann, M.; Schmidt, M. W.; Pettke, T.

2003-12-01

Low-Ca pyroxene or pigeonite ( ˜0.25-0.35 Ca per formula unit, pfu) is an important residual phase during high temperature melting of refractory mantle (e.g., ankaramite formation). High-Ca cpx (>0.6-0.7 Ca pfu) may be residual to relatively low temperature melting of fertile mantle (MOR and OI), but the opx-cpx solvus narrows considerably at higher temperatures (>1330-1350° C), leading to coexisting opx and low-Ca cpx. Little is known about the trace element partitioning of such low-Ca cpx at upper mantle conditions. Our new partitioning experiments investigate the role of low-Ca cpx during melting of depleted peridotite. Nominally anhydrous experiments with graphite-lined Pt-capsules were conducted at 1.4 GPa and 1360-1370° C. The synthetic starting material is close in composition to an ultracalcic liquid saturated in opx+pigeonite+olivine+spinel. The experiments yielded assemblages of glass, low-Ca cpx, ol, and minor Cr-spinel; opx is absent. The low-Ca clinopyroxenes have 0.20 and 0.32 Ca pfu at 1370 and 1360° C, respectively, and tetrahedral Al of 0.046 and 0.067 pfu. The liquids have ˜50 wt% SiO2, ˜12.5 wt% CaO and CaO/Al2O3 of 1.44-1.54. Pyroxenes and glasses were analyzed for trace elements (La, Ce, Nd, Sm, Eu, Gd, Dy, Er Yb, Lu, Sc, Y, Sr, Zr, Hf, V, Cr, Mn, Co, Zn) by LA-ICP-MS using a 193 nm ArF excimer laser coupled to an Elan 6100 mass spectrometer. Ablation occurred in He, and ablation spot sizes were 15-30 μ m for minerals and 50 μ m for glasses. Trace element concentrations in pyroxenes were low for most 3+ and 4+ cations. This resulted in small mineral/melt partition coefficients (D-values), approximately an order of magnitude lower than those for high-Ca cpx associated with peridotite melting, thus making the low-Ca cpx partitioning behavior rather similar to the behavior of peridotitic opx. Cpx with 0.32 Ca pfu has slightly elevated D-values for 3+ cations when compared to the 0.20 Ca pfu cpx: DSc = 0.45, DY = 0.11, DSm = 0.054 and DYb = 0.141, compared to values of 0.32, 0.065, 0.016 and 0.075, respectively. Regardless of Ca content, V, Mn, Co and Zn are mildly incompatible (Ds ˜0.5-0.9). Therefore, only Sc, V, Cr, Mn, Co, Ni and Zn are retained during partial mantle melting with a pigeonite+opx+ol residue. Most other elements partition strongly into the melt, and barring exotic residual minerals, the composition of ultracalcic liquids reflects the incompatible trace element budget of the depleted peridotite source.

Trace element partitioning in rock forming minerals of co-genetic, subduction-related alkaline and tholeiitic mafic rocks in the Ural Mountains, Russia

NASA Astrophysics Data System (ADS)

Krause, J.; Brügmann, G. E.; Pushkarev, E. V.

2009-04-01

The partitioning of trace elements between rock forming minerals in igneous rocks is largely controlled by physical and chemical parameters e.g. temperature, pressure and chemical composition of the minerals and the coexisting melt. In the present study partition coefficients for REE between hornblende, orthopyroxene, feldspars, apatite and clinopyroxene in a suite of co-genetic alkaline and tholeiitic mafic rocks from the Ural Mountains (Russia) were calculated. The results give insights to the influence of the chemical composition of the parental melt on the partitioning behaviour of the REE. Nepheline-bearing, alkaline melanogabbros (tilaites) are assumed to represent the most fractionated products of the melt that formed the ultramafic cumulates in zoned mafic-ultramafic complexes in the Ural Mountains. Co-genetic with the latter is a suite of olivine gabbros, gabbronorites and hornblende gabbros formed from a tholeiitic parental melt. Negative anomalies for the HFSE along with low Nb and Ta contents and a positive Sr anomaly indicate a subduction related origin of all parental melts. The nepheline gabbros consist predominantly of coarse-grained clinopyroxene phenocrysts in a matrix of fine grained clinopyroxene, olivine, plagioclase, K-feldspar and nepheline with accessory apatite. The tholeiitic gabbros have equigranular to porphyric textures with phenocrysts of olivine, pyroxene and hornblende in a plagioclase rich matrix with olivine hornblende, pyroxene and accessory apatite. Element concentrations of adjacent matrix grains and rims of phenochrysts were measured with LA-ICPMS. The distribution of REE between hornblende and clinopyroxene in the tholeiitic rocks is similar for most of the elements (DHbl•Cpx(La-Tm) = 2.7-2.8, decreasing to 2.6 and 2.4 for Yb and Lu, respectively). These values are about two times higher than published data (e.g. Ionov et al. 1997). Partition coefficients for orthopyroxene/clinopyroxene systematically decrease from the HREE (DOpx•Cpx(Lu) = 0.31) towards the LREE (DOpx•Cpx(Nd) = 0.01). The partition coefficients for plagioclase/clinopyroxene and K-feldspar/clinopyroxene in the alkaline melanogabbros decrease from the LREE (DPlg•Cpx(La) = 0.91, DK-fs•Cpx(La)=0.26) to the MREE (DPlg•Cpx(Sm) = 0.02, DK-fs•Cpx(Sm) = 0.006), but both mineral pairs have similar DEu (DPlg•Cpx(Eu) = 0.25, DK-fs•Cpx(Eu) = 0.23). Plagioclase/clinopyroxene partition coefficients for all REE in the tholeiitic gabbros are 3-5 times higher, if compared to those of the alkaline gabbros (DPlg•Cpx(La) = 1.7, DPlg•Cpx(Sm) = 0.034). Apatite/clinopyroxene partition coefficients for the REE decrease from the LREE (DAp•Cpx(La) = 65 in alkaline and 120 in tholeiitic gabbro) to the HREE (DAp•Cpx(Lu) = 4.5 in alkaline and 5.3 in tholeiitic gabbro). The lower partition coefficients for apatite/clinopyroxene and plagioclase/clinopyroxene in the alkaline melanogabbros can be explained by higher clinopyroxene/melt partition coefficients in this system. The higher Al2O3-content in clinopyroxene from the alkali gabbros (Al2O3 = 3.5-7 wt.%), if compared to clinopyroxene in the tholeiitic gabbros (Al2O3 = 2.0-4.5 wt.%) can account for a stronger partitioning of the REE into clinopyroxene in the alkaline rocks (e.g. Gaetani and Grove 1995). Experimental data by Gaetani (2004) also indicate a systematic increase of the Cpx/melt partition coefficients for the REE with increasing Al2O3 and Na2O contents of the parental melt in mafic systems. This is in agreement with the assumed compositional differences between the alkaline and the tholeiitic parental melts. Gaetani, G.A., 2004. Contributions to Mineralogy and Petrology, Vol. 147, 511-527. Gaetani, G.A., Grove, T.L, 1995. Geochimica et Cosmochimica Acta, Vol. 59, 1951-1962. Ionov, D.A., Griffin, W.L., O'Reily, S.Y., 1997. Chemical Geology, Vol. 141, 153-184.

High water concentrations in a primitive Deccan lava: evidence from clinopyroxene crystals

NASA Astrophysics Data System (ADS)

Seaman, Sheila

2017-04-01

Measurements of water concentrations in clinopyroxene phenocrysts in the Powai ankaramite flow, located near Mumbai, west of the Western Ghats escarpment of the Deccan province, India, indicate that the parent magma of the flow hosted at least 4.3 wt.% water, an unusually high water concentration for a continental flood basalt magma. However, similar water concentrations (3.39 to 6.61 wt.%) were calculated by Xia et al. (2016), also on the basis of water concentrations in clinopyroxene crystals, for continental basalts of the Tarin basin in northwestern China, which hosts >200,000 km3 of flood basalts (Xia et al., 2016). In the Powai ankaramite flow, textural and compositional features of clinopyroxene phenocrysts further support crystallization in a water-rich melt. The flow hosts clinopyroxene and olivine phenocrysts. Chatterjee and Sheth (2015) showed that phenocrysts in the flow were part of a cumulate layer intruded by high-temperature basaltic melt at 6 kb and 1230oC, so the phenocrysts record characteristics of the cumulate parent melt. Clinopyroxene phenocrysts are large (to 0.5 cm diameter), euhedral, are oscillatorily zoned in water, Mg, Fe, and Ca concentrations, and have concentric bands 100-200 microns thick of fine (10-20 micron diameter) melt inclusions. Olivine phenocrysts are smaller (to 0.1 cm diameter, are unzoned, and host only larger isolated melt inclusions. Zones in the cpx phenocrysts where melt inclusion-rich concentric bands occur have higher concentrations of water than inclusion-free zones. Water concentrations of cpx were used to calculate water concentrations in the melt from which the crystals formed using partition coefficients of Hauri et al. (2004). Water concentrations in the parent magma were between 4.35 and 8.26 wt. % based on water concentrations in cpx. Both Mg and Fe are relatively depleted in the water- and melt inclusion-rich zones in cpx, and Ca is enriched in these zones. Oscillatory zoning in cpx may be a result of repeated growth of cpx in water-richer and water-poorer boundary layers in which water lowered melt viscosity and enhanced diffusion and crystal growth rates. Water-enhanced growth rates may have resulted in capture of melt inclusions preserved in water-rich cpx zones. Mg was preferentially incorporated into the cpx, causing Ca and water to build up in the boundary layer, and Mg and Fe to become relatively depleted in the boundary layer, as discussed for oscillatorially-zoned minerals by Wang and Merino (1993). These apparently water-dependent variations in crystal growth processes ugsuggest that at least this Deccan magma was relatively hydrous. Melt inclusions in olivine phenocrysts, however, preserve lower water concentrations ( 1.2 wt. %) than those indicated by water concentration in cpx phenocrysts. This disparity may be evidence of water loss from melt inclusions in olivine (Gaetani et al., 2009) or may indicate that cpx and ol crystals did not crystallize from the same parent at the same time.

Emergence as an outbreak of the HIV-1 CRF19_cpx variant in treatment-naïve patients in southern Spain.

PubMed

González-Domenech, Carmen M; Viciana, Isabel; Delaye, Luis; Mayorga, María Luisa; Palacios, Rosario; de la Torre, Javier; Jarilla, Francisco; Castaño, Manuel; Del Arco, Alfonso; Clavijo, Encarnación; Santos, Jesús

2018-01-01

CRF19_cpx is a complex circulating recombination form (CRF) of HIV-1. We describe the characteristics of an outbreak of the CRF19_cpx variant among treatment-naïve patients in southern Spain. The study was undertaken at the Virgen de la Victoria Hospital, a reference centre for the analysis of HIV-1 genotype in Malaga (Spain). Subtyping was performed through REGA v3.0 and the relationship of our CRF19_cpx sequences, among themselves and regarding other reference sequences from the same variant, was defined by phylogenetic analysis. We used PhyML program to perform a reconstruction of the phylogeny by Maximum Likelihood method as well as further confirmation of the transmission clusters by Bayesian inference. Additionally, we collected demographic, clinical and immunovirological data. Between 2011 and 2016, we detected 57 treatment-naïve patients with the CRF19_cpx variant. Of these, 55 conformed a very well-defined transmission cluster, phylogenetically close to CRF19_cpx sequences from the United Kingdom. The origin of this subtype in Malaga was dated between 2007 and 2010. Over 50% of the patients presented the non-nucleoside reverse transcriptase inhibitor G190A resistance mutation. This variant was mostly represented by young adult Spanish men who had sex with men. Almost half of them were recent seroconverters, though a similar percentage was diagnosed at a late state of HIV infection. Five cases of AIDS and one non-AIDS defined death occurred during follow-up. The majority of patients treated with first-line combination antiretroviral therapy (ART) responded. We report the largest HIV-1 CRF19_cpx cohort of treatment-naïve patients outside Cuba, almost all emerging as an outbreak in the South of Spain. Half the cases had the G190A resistance mutation. Unlike previous studies, the variant from Malaga seems less pathogenic, with few AIDS events and an excellent response to ART.

Predicting failing performance on a standardized patient clinical performance examination: the importance of communication and professionalism skills deficits.

PubMed

Chang, Anna; Boscardin, Christy; Chou, Calvin L; Loeser, Helen; Hauer, Karen E

2009-10-01

The purpose is to determine which assessment measures identify medical students at risk of failing a clinical performance examination (CPX). Retrospective case-control, multiyear design, contingency table analysis, n = 149. We identified two predictors of CPX failure in patient-physician interaction skills: low clerkship ratings (odds ratio 1.79, P = .008) and student progress review for communication or professionalism concerns (odds ratio 2.64, P = .002). No assessments predicted CPX failure in clinical skills. Performance concerns in communication and professionalism identify students at risk of failing the patient-physician interaction portion of a CPX. This correlation suggests that both faculty and standardized patients can detect noncognitive traits predictive of failing performance. Early identification of these students may allow for development of a structured supplemental curriculum with increased opportunities for practice and feedback. The lack of predictors in the clinical skills portion suggests limited faculty observation or feedback.

Control of the proinflammatory state in cystic fibrosis lung epithelial cells by genes from the TNF-alphaR/NFkappaB pathway.

PubMed Central

Eidelman, O.; Srivastava, M.; Zhang, J.; Leighton, X.; Murtie, J.; Jozwik, C.; Jacobson, K.; Weinstein, D. L.; Metcalf, E. L.; Pollard, H. B.

2001-01-01

BACKGROUND: Cystic fibrosis (CF) is the most common, lethal autosomal recessive disease affecting children in the United States and Europe. Extensive work is being performed to develop both gene and drug therapies. The principal mutation causing CF is in the CFTR gene ([Delta F508]CFTR). This mutation causes the mutant protein to traffic poorly to the plasma membrane, and degrades CFTR chloride channel activity. CPX, a candidate drug for CF, binds to mutant CFTR and corrects the trafficking deficit. CPX also activates mutant CFTR chloride channel activity. CF airways are phenotypically inundated by inflammatory signals, primarily contributed by sustained secretion of the proinflammatory cytokine interleukin 8 (IL-8) from mutant CFTR airway epithelial cells. IL-8 production is controlled by genes from the TNF-alphaR/NFkappaB pathway, and it is possible that the CF phenotype is due to dysfunction of genes from this pathway. In addition, because drug therapy with CPX and gene therapy with CFTR have the same common endpoint of raising the levels of CFTR, we have hypothesized that either approach should have a common genomic endpoint. MATERIALS AND METHODS: To test this hypothesis, we studied IL-8 secretion and global gene expression in IB-3 CF lung epithelial cells. The cells were treated by either gene therapy with wild-type CFTR, or by pharmacotherapy with the CFTR-surrogate drug CPX. CF cells, treated with either CFTR or CPX, were also exposed to Pseudomonas aeruginosa, a common chronic pathogen in CF patients. cDNA microarrays were used to assess global gene expression under the different conditions. A novel bioinformatic algorithm (GENESAVER) was developed to identify genes whose expression paralleled secretion of IL-8. RESULTS: We report here that IB3 CF cells secrete massive levels of IL-8. However, both gene therapy with CFTR and drug therapy with CPX substantially suppress IL-8 secretion. Nonetheless, both gene and drug therapy allow the CF cells to respond with physiologic secretion of IL-8 when the cells are exposed to P. aeruginosa. Thus, neither CFTR nor CPX acts as a nonspecific suppressor of IL-8 secretion from CF cells. Consistently, pharmacogenomic analysis indicates that CF cells treated with CPX greatly resemble CF cells treated with CFTR by gene therapy. Additionally, the same result obtains in the presence of P. aeruginosa. Classical hierarchical cluster analysis, based on similarity of global gene expression, also supports this conclusion. The GENESAVER algorithm, using the IL-8 secretion level as a physiologic variable, identifies a subset of genes from the TNF-alphaR/NFkappaB pathway that is expressed in phase with IL-8 secretion from CF epithelial cells. Certain other genes, previously known to be positively associated with CF, also fall into this category. Identified genes known to code for known inhibitors are expressed inversely, out of phase with IL-8 secretion. CONCLUSIONS: Wild-type CFTR and CPX both suppress proinflammatory IL-8 secretion from CF epithelial cells. The mechanism, as defined by pharmacogenomic analysis, involves identified genes from the TNF-alphaR/NFkappaB pathway. The close relationship between IL-8 secretion and genes from the TNF-alphaR/NFkappaB pathway suggests that molecular or pharmaceutical targeting of these novel genes may have strategic use in the development of new therapies for CF. From the perspective of global gene expression, both gene and drug therapy have similar genomic consequences. This is the first example showing equivalence of gene and drug therapy in CF, and suggests that a gene therapy-defined endpoint may prove to be a powerful paradigm for CF drug discovery. Finally, because the GENESAVER algorithm is capable of isolating disease-relevant genes in a hypothesis-driven manner without recourse to any a priori knowledge about the system, this new algorithm may also prove useful in applications to other genetic diseases. PMID:11591888

Li-Be-B Systematics of mantle Xenoliths from Harrat Uwayrid (Saudi Arabia)

NASA Astrophysics Data System (ADS)

Kaliwoda, M.; Altherr, R.

2003-04-01

The Harrat Uwayrid is a Late Miocene to Quaternary volcanic field located in the northwestern part of the Arabian plate and related to the opening of the Red Sea. Numerous cinder cones contain abundant mantle xenoliths. Based on mineralogy and textures, these xenoliths can be subdivided into 3 different groups. Group IA1 are "anhydrous" spinel lherzolites and harzburgites consisting of olivine (ol), orthopyroxene (opx), clinopyroxene (cpx) and spinel (spl). Group IA2 xenoliths represent group IA1 materials that were moderately metasomatized. In addition to cpx, opx, ol and spl these xenoliths contain subordinate amounts of Cr-pargasite (par). Group IB xenoliths were strongly metasomatized by fluids and fluid-rich melts resulting in newly formed Ba-phlogopite (phl), Ba-bearing pargasite, Ba-feldspar (celsian) and Ba-rich phonolitic glasses. Li-Be-B systematics of the different xenoliths were studied by secondary ion mass spectrometry (SIMS). The results show that the partitioning of Li, Be and B among the various minerals is virtually independent of pressure and temperature. The absolute abundances, however, depend on the degree of initial depletion and later metasomatic overprint. Group IA1 spinel lherzolites are characterized by Li(cpx) = 0.65-1.19 µg/g, Li(opx) = 1.29-1.63 µg/g and Li(ol) = 2.15-2.43 µg/g, while group IB xenoliths show much higher abundances of Li: Li(cpx) = 1.89-2.16 µg/g, Li(opx) = 1.88-2.83 µg/g, Li(ol) = 3.06-4.12 µg/g. Similar differences are observed for the abundances of B (IA1: B(cpx) = 0.46-0.83 µg/g, B(opx) = 0.047-0.189 µg/g, B(ol) = 0.16-1.15 µg/g; IB: B(cpx) = 0.16-1.15 µg/g, B(opx)= 1.01-1.47 µg/g, B(ol) = 0.44-0.55 µg/g). In marked contrast to Li and B, the abundances of Be were not changed during metasomatism. Group IA1 xenoliths are characterized by Be(cpx) = 0.09-0.13 µg/g, Be(opx) = 0.023-0.027 µg/g and Be(ol) = 0.002 µg/g and group IB xenoliths show Be(cpx) = 0.05-0.09 µg/g, Be(opx) = 0.03-0.08 µg/g and Be(ol) < 0.001 µg/g.

Sr and Nd Data for Upper Eocene Spherule Layers

NASA Technical Reports Server (NTRS)

Liu, Shaobin; Glass, B. P.; Ngo, H. H.; Papanastassiou, D. A.; Wasserburg, G. J.

2001-01-01

Sr and Nd data for clinopyroxene-bearing (cpx) spherules from three sites support conclusions that there is only one cpx spherule layer and that the source crater may be Popigai. Additional information is contained in the original extended abstract.

Removal of Ciprofloxacin from Aqueous Solutions Using Pillared Clays

PubMed Central

Roca Jalil, Maria Eugenia; Baschini, Miria; Sapag, Karim

2017-01-01

Emerging contaminants in the environment have caused enormous concern in the last few decades, and among them, antibiotics have received special attention. On the other hand, adsorption has shown to be a useful, low-cost, and eco-friendly method for the removal of this type of contaminants from water. This work is focused on the study of ciprofloxacin (CPX) removal from water by adsorption on pillared clays (PILC) under basic pH conditions, where CPX is in its anionic form (CPX−). Four different materials were synthetized, characterized, and studied as adsorbents of CPX (Al-, Fe-, Si-, and Zr-PILC). The highest CPX adsorption capacities of 100.6 and 122.1 mg g−1 were obtained for the Si- and Fe-PILC (respectively), and can be related to the porous structure of the PILCs. The suggested adsorption mechanism involves inner-sphere complexes formation as well as van der Waals interactions between CPX− and the available adsorption sites on the PILC surfaces. PMID:29168798

The non-serpentine phases in serpentinites from the Braszowice-Brzeźnica Massif (SW Poland) as traces of magmatic processes within oceanic mantle

NASA Astrophysics Data System (ADS)

Wojtulek, Piotr; Puziewicz, Jacek; Ntaflos, Theodoros

2016-04-01

The Braszowice-Brzeźnica Massif - BBM (SW Poland) is a part of the Variscan Central-Sudetic Ophiolite. It is located at the southern termination of the Niemcza Shear Zone and consists of gabbros and serpentinites. The ultramafic rocks occurring in the BBM are (from E to W) serpentinites with abundant relics of olivine and tremolite, lizardite-chrysotile serpentinites and antigorite serpentinites. Clinopyroxene, olivine and zoned chromite grains were found in the central part of the BBM (Mnich Hill) within antigoritic serpentinites. The non-serpentine phases occur in the following microstructures: (1) olivine-chromite aggregates: olivine (Fo = 90.0-91.0) contains 0.35-0.44 wt.% NiO, elongated or amaeboidal chromite I (Cr# = 0.49-0.50, TiO2 = 0.14-0.15 wt.%) is rimmed by chromite II (Cr# = 0.98, TiO2 = 0.01 wt.%); (2) coarse and dismembered diopside grains (Cpx I, Mg# = 0.91-0.92) containing 0.70-0.80 wt.% TiO2, 3.0-4.0 wt.% Al2O3, 1.0-1.4 Cr2O3 and 0.3-0.5 wt.% Na2O; Cpx I is enriched in REE relative to primitive mantle, the REE pattern reveals HREE enrichment relative to LREE and negative Eu anomaly; (3) olivine-clinopyroxene aggregates: olivine (Fo = 90.4-91.3) contains 0.27-0.35 wt.% NiO, anhedral, often elongated clinopyroxene (Cpx II, Mg# = 0.91-0.92) has <0.1 wt.% TiO2, 3.00-4.00 wt.% Al2O3, 1.00-1.40 Cr2O3 and <0.20 wt.% Na2O, (4) magnetite-bearing olivine grains, locally in aggregates with minute clinopyroxene ones; olivine has variable Fo (86.0-96.0) and NiO concentration (0.02-0.55 wt.%), clinopyroxene (Cpx III, Mg# = 0.93-0.97) contains <0.40 wt.% Al2O3 and <0.20 Cr2O3. Cpx III rims also locally Cpx II. The non-serpentine phases from the BBM massif have various compositions and mode of occurrence, thus they record various crystallization events. Composition of chromite I is similar to primary chromite grains occurring in oceanic peridotites of the Romanche and Kurchatov F.Z. (Dick and Bullen, 1984), thus the olivine-chromite aggregates represent probably primary mantle phases. Cpx I contains similar amount of the Al2O3, Cr2O3 and Na2O to primary diopsides described from the Marie Celeste FZ and Indomed FZ (Johnson et al., 1990). REE pattern of the Cpx I suggests depletion in mobile trace elements due to melt extraction. Cpx II has Al2O3, Cr2O3 and TiO2 contents similar to those of diopside originated from the melt-percolation reactions, olivine coexisting with Cpx II crystallized probably in the same event. The Cpx III has Al, Cr and Na contents typical for secondary, metamorphic clinopyroxene. Magnetite-bearing olivine is similar to olivine crystallized at expense of serpentine+magnetite precursors, thus is has secondary, metamorphic origin. This abstract was prepared as a part of the project of the National Science Centre of Poland ("Evolution of serpentinic members of the Lower Silesia ophiolites", DEC-2012/07/N/ST10/03934). References Dick, H.J.B., Bullen, T., 1984. Chromian spinel as a petrogenetic indicator in abyssal and alpine-type peridotites and spatially associated lavas. Contributions to Mineralogy and Petrology 86, 54-76. Johnson K.T.M., Dick H.J.B., Shimizu N., 1990. Melting in the Oceanic Upper Mantle - an ion microprobe study of Diopsides in Abyssal Peridotites. Journal of Geophysical Research 95, 2661-2678.

Role of the cell envelope stress regulators BaeR and CpxR in control of RND-type multidrug efflux pumps and transcriptional cross talk with exopolysaccharide synthesis in Erwinia amylovora.

PubMed

Pletzer, Daniel; Stahl, Antje; Oja, Anna Elisabeth; Weingart, Helge

2015-08-01

The purpose of this study was to identify the role of the cell envelope stress-sensing systems BaeSR and CpxARP in regulation of multidrug efflux and exopolysaccharide synthesis in Erwinia amylovora. We have previously reported that BaeR activates transcription of the RND-type efflux pumps AcrD and MdtABC. In this study, we found that a cpxR-deficient mutant was highly susceptible to β-lactams, aminoglycosides and lincomycin, whereas a baeR mutant showed no change in antimicrobial sensitivity. However, overexpression of BaeR in a mutant lacking the major RND pump AcrB increased resistance of E. amylovora to several compounds that are not substrates of AcrD or MdtABC. Furthermore, we observed that overexpression of BaeR significantly increased amylovoran production. Moreover, the expression of RND-type efflux pumps was changed in regulatory mutants of exopolysaccharide production. Our data suggest that BaeSR and CpxARP regulate additional mechanisms, beside efflux, which are responsible for antimicrobial resistance of E. amylovora.

The localization of a gene causing X-linked cleft palate and ankyloglossia (CPX) in an Icelandic kindred is between DXS326 and DXYS1X

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stainer, P.; Forbes, S.A.; Moore, G.

1993-09-01

The locus responsible for X-linked, nonsyndromic cleft palate and/or ankyloglossia (CPX) has previously been mapped to the proximal long arm of the human X chromosome between Xq21.31 and q21.33 in an Icelandic kindred. The authors have extended these studies by analyzing an additional 14 informative markers in the family as well as including several newly investigated family members. Recombination analysis indicates that the CPX locus is more proximal than previously thought, within the interval Xq21.1-q21.31. Two recombinants place DXYS1X as the distal flanking marker, while one recombinant defines DXS326 as the proximal flanking marker, an interval of less than 5more » cM. Each of the flanking markers recombines with the CPX locus, giving 2-point lod scores of Z[sub max] = 4.16 at [theta] = 0.08 (DXS326) and Z[sub max] = 5.80 at [theta] = 0.06 (DXYS1X). 35 refs., 3 figs., 2 tabs.« less

Intracrystalline "geothermometry" assessed on clino and orthopyroxene bearing synthetic rocks

NASA Astrophysics Data System (ADS)

Murri, M.; Cámara, F.; Adam, J.; Domeneghetti, M. C.; Alvaro, M.

2018-04-01

Recent discussion on the application of intracrystalline "geothermometers" based on the Fe-Mg order-disorder reaction in pyroxene in natural rocks, indicates that the available calibration equations for clino and orthopyroxenes (cpx and opx), which express the equilibrium intracrystalline Fe-Mg distribution coefficient kD(Fe-Mg) as a function of temperature, require independent validation. In this paper, we tested the available experimental calibrations for clino and orthopyroxenes by determining the site occupancies of these minerals in synthetic samples grown from a hydrous nepheline basanite in a piston-cylinder apparatus at 1050 °C at 2.0 GPa to 1170 °C at 3.0 GPa, and quenched very rapidly by shutting off the power. The site occupancies were determined by single crystal X-ray diffraction (SC-XRD) and used to calculate the closure temperature, TC, of cation ordering using available calibrations of kD(Fe-Mg) vs. T. The calculated TC values of both clino and orthopyroxenes were found to be close to the temperatures at which they were quenched, in line with expected kinetic behavior, when calibrations for cpx (Murri et al., 2016) and opx (Stimpfl et al., 2005) based on SC-XRD structure refinements were used. In particular, the smallest discrepancy between calculated and actual temperature is of the order of a few degrees (12 °C for cpx and 4 °C for opx), and the largest is of the order of tens of degrees (22 °C for cpx and 55 °C for opx). On the other hand, much lower TCs were obtained when calibrations based on Mössbauer determination of site occupancies were used. These results confirm that the two methods (i.e. SC-XRD and Mössbauer) give inherently different site occupancy data and that the same methodology should thus be used for both calibration and natural samples in the determination of cooling rate of host rocks.

Primary Mineralogical and Chemical Characteristics of the Major K/T and Late Eocene Impact Deposits

NASA Technical Reports Server (NTRS)

Kyte, Frank T.

2004-01-01

Three well-characterized, distal impact deposits at the WT boundary and in upper Eocene sediments serve as a baseline for understanding other proposed impact deposits. All contain abundant spherules, evidence of shock metamorphism, and the largest have significant extraterrestrial components (ETCs). The K/T and the Eocene cpx-spherule (cpxS) deposits are global - likely from the events that produced the 180 km Chicxulub and 100 km Popigai craters. The Eocene North American microtektite (NAM) deposit is regional and likely from the event that produced the 45 km Chesapeake Bay crater. These deposits all contain abundant spherules formed from both shock-melted target and mixtures of target and projectile in the ejecta plume. Spherules constitute most of the mass of the distal ejecta. K/T spherules in regional deposits around the Gulf of Mexico are from low-velocity, target-rich ejecta. These can be a few mm in size and form deposits 10s of cm thick. Globally deposited KIT spherules from the plume (typically a few hundred micron size) are both target- and projectile-rich. When well preserved, the global deposits are 3 mm thick. Eocene cpxS deposits are similar to distal K/T with both target- and projectile-rich varieties (Le., glassy microtektite, and cpx spherules). They are smaller on average than WT spherules, concentrated in the 125-250 micron and smaller fractions. They are invariably bioturbated, but the initial deposit was probably less than 1 mm thick. The NAM are composed entirely of target-rich glass. They are similar in size to the cpxS. Size is an important criterion for distal ejecta because droplet size in the impact plume is proportional to the energy of the impact. Both the JUT and cpxS deposits are characterized by well-defined ETCs, commonly measured by Ir. The total Ir deposited is about 55 ng per square cm in WT sediments, and about 11 ng for the cpxS layer. This 5/1 proportion in Ir is generally consistent with the approx.1.8/1 ratio in crater diameters. The NAM have no significant ETC. This may be a function of the smaller impact. It indicates there was no significant projectile-rich plume deposit.

Voluminous arc dacites as amphibole reaction-boundary liquids

USGS Publications Warehouse

Blatter, Dawnika; Sisson, Thomas W.; Hankins, William B.

2017-01-01

Dacites dominate the large-volume, explosive eruptions in magmatic arcs, and compositionally similar granodiorites and tonalites constitute the bulk of convergent margin batholiths. Shallow, pre-eruptive storage conditions are well known for many dacitic arc magmas through melt inclusions, Fe–Ti oxides, and experiments, but their potential origins deeper in the crust are not well determined. Accordingly, we report experimental results identifying the P–T–H2O conditions under which hydrous dacitic liquid may segregate from hornblende (hbl)-gabbroic sources either during crystallization–differentiation or partial melting. Two compositions were investigated: (1) MSH–Yn−1 dacite (SiO2: 65 wt%) from Mount St. Helens’ voluminous Yn tephra and (2) MSH–Yn−1 + 10% cpx to force saturation with cpx and map a portion of the cpx + melt = hbl peritectic reaction boundary. H2O-undersaturated (3, 6, and 9 wt% H2O) piston cylinder experiments were conducted at pressures, temperatures, and fO2 appropriate for the middle to lower arc crust (400, 700, and 900 MPa, 825–1100 °C, and the Re–ReO2 buffer ≈ Ni–NiO + 2). Results for MSH–Yn−1 indicate near-liquidus equilibrium with a cpx-free hbl-gabbro residue (hbl, plg, magnetite, ± opx, and ilmeno-hematite) with 6–7 wt% dissolved H2O, 925 °C, and 700–900 MPa. Opx disappears down-temperature consistent with the reaction opx + melt = hbl. Cpx-added phase relations are similar in that once ~10% cpx crystallizes, multiple saturation is attained with cpx, hbl, and plg, +/− opx, at 6–7 wt% dissolved H2O, 940 °C, and 700–900 MPa. Plg–hbl–cpx saturated liquids diverge from plg–hbl–opx saturated liquids, consistent with the MSH–Yn−1 dacite marking a liquid composition along a peritectic distributary reaction boundary where hbl appears down-temperature as opx + cpx are consumed. The abundance of saturating phases along this distributary peritectic (liquid + hbl + opx + cpx + plg + oxides) reduces the variance, so liquids are restricted to dacite–granodiorite–tonalite compositions. Higher-K dacites than the Yn would also saturate with biotite, further limiting their compositional diversity. Theoretical evaluation of the energetics of peritectic melting of pargasitic amphiboles indicates that melting and crystallization of amphibole occur abruptly, proximal to amphibole’s high-temperature stability limit, which causes the system to dwell thermally under the conditions that produce dacitic compositions. This process may account for the compositional homogeneity of dacites, granodiorites, and tonalites in arc settings, but their relative mobility compared to rhyolitic/granitic liquids likely accounts for their greater abundance.

Subduction-related metasomatism in French Massif Central: evidence from secondary orthopyroxene in mantle xenoliths.

NASA Astrophysics Data System (ADS)

Wagner, Christiane

2017-04-01

Peridotite xenoliths from the French Massif Central (FMC) have undergone a complex mantle metasomatic history by percolation of various melts/ fluids from alkali basaltic to carbonatite composition. This contribution argues for the imprint of another type of metasomatism related to subduction-derived melts/fluids. The samples come from the Mont Coupet strombolian volcano, Devès, FMC. They are fresh protogranular spinel lherzolites, with no infiltration of the host basanitic magma, but with evidences of alkali and carbonate-related metasomatism discussed elsewhere [1-3]. This study focuses on secondary orthopyroxene (opx2). It occurs +/- minor secondary clinopyroxene (cpx2) in cross-cutting thin (10 µm-20 µm) veinlets, and also as discontinuous patches developed after primary clinopyroxene (cpx1) at the contact with primary olivine (ol1). Opx2 crystals do not form fibrous radial aggregates. Rare small (<1 µm) rounded chloroapatite is included in opx2 after cpx1. Small (2 µm) pores are observed throughout the veins, at the contact with ol1, along sub-grained boundaries between opx2 and cpx2 in the veinlets, and between opx2 and cpx1. The primary minerals crosscut by the veinlets do not show any compositional zoning and the different elements show sharp profiles between opx 2 and primary minerals. Compared to primary opx, opx2 are characterized by a lower content in Al2O3 (1.7-2.5 wt. %) / 3.2-4.0 wt. %). They are slightly MgO (XMg = 90-91/ 89-90) and CaO richer (0.5 wt. % / 0.3 wt. %), and contain slightly less Cr2O3 (<0.2 wt. % / 0.2-0.3wt. %) and TiO2 (<0.06 wt. % / 0.06-0.14 wt. %), although there is some crossover between the two data sets. Na2O contents (<0.05 wt. %) are comparable. Cpx2 and opx2 from the veinlets are in equilibrium (XMg = 90-92). Al and Ti contents in cpx2 exclude any influence of percolation of the host magma. Moreover, their high Al6/Al4 ratio points to an equilibration at higher pressure than igneous cpx, close to that of cpx1. These data are compared with data on opx2 in mantle xenoliths, mostly observed in the mantle wedge above active or inactive subduction zones ([4] and references therein), as well as experimental data [5, 6]. These metasomatic opx2 are characterized by lower Al, Ca and Cr than opx1, as observed in Mont Coupet. Together with the presence of pores and of chloroapatite, the compositional characteristics of our samples are interpreted as the signature of Si-rich and Cl-bearing metasomatic fluids. They are similar to slab-derived fluids and may be in relation to the subduction event occurring during the Variscan orogeny, a possibility envisaged by [3] from recent Li isotopic studies. [1] Wagner, Goldschmidt Conf., 2015; [2] Wagner & Deloule, EGU, 2016; [3] Gu, PhD Thesis, Nancy, France, 2016; [4] Benard & Ionov, J. Petrol., 2013; [5] Perchuk & Yapaskurt, Geoch. Intern., 2013; [6] Grant et al, Am. Mineral., 2016.

Fractional ultrabasic-basic evolution of upper-mantle magmatism: Evidence from xenoliths in kimberlites, inclusions in diamonds and experiments

NASA Astrophysics Data System (ADS)

Litvin, Yuriy; Kuzyura, Anastasia

2017-04-01

Ultrabasic peridotites and pyroxenites together with basic eclogites are the upper-mantle in situ rocks among xenoliths in kimberlites. Occasionally their diamond-bearing varieties have revealed within the xenoliths. Therewith the compositions of rock-forming minerals demonstrate features characteristic for primary diamond-included minerals of peridotite and eclogite parageneses (the elevated contents of Cr-component in peridotitic garnets and Na-jadeitic component in eclogitic clinopyroxenes). High-pressure experimental study of melting equilibria on the multicomponent peridotie-pyroxenite system olivine Ol - orthopyroxene Opx - clinopyroxene Cpx - garnet Grt showed that Opx disappeared in the peritectic reaction Opx+L→Cpx (Litvin, 1991). As a result, the invariant peritectic equilibrium Ol+Opx+Cpx+Grt+L of the ultrabasic system was found to transform into the univariant cotectic assemblage Ol+Cpx+Grt+L. Further experimental investigation showed that olivine reacts with jadeitic component (Jd) with formation of garnet at higher 4.5 GPa (Gasparik, Litvin, 1997). Study of melting relations in the multicomponent system Ol - Cpx - Jd permits to discover the peritectic point Ol+Omph+Grt+L (where Omph - omphacitic clinopyroxene) at concentration 3-4 wt.% Jd-component in the system. The reactionary loss of Opx and Ol makes it possible to transform the 4-phase garnet lherzolite ultrabasic association into the bimineral eclogite assemblage. The regime of fractional Ol, Cpx and Grt crystallization must be accompanied by increasing content of jadeitic component in residual melts that causes the complete "garnetization of olivine". In the subsequent evolution, the melts would have to fractionate for basic SiO2-saturated compositions responsible for petrogenesis of eclogite varieties marked with accessory corundum Crn, kyanite Ky and coesite Coe. Both the peritectic mechanisms occur in regime of fractional crystallization. The sequence of the upper-mantle fractional ultrabasic-basic magmatic evolution and petrogenesis may be controlled by the following melting relations: from Ol, Opx, L field to cotectic curve Ol, Opx, Cpx, L, peritectic point Ol, Opx, Cpx, Grt, L (loss of Opx), cotectic curve Ol, (Cpx+Jd), Grt, L, peritectic point Ol, (Cpx→Omph), Grt, L (loss of Ol), divariant field Omph,Grt,L, cotectic curve Ky, Omph, Grt, L, eutectic point Ky,Coe,Omph, Grt,L, subsolidus assemblage Ky,Coe,Omph, Grt. The fractional ultrabasic-basic evolution of the upper-mantle silicate-carbonate-carbon melts-solutions, which are responsible for genesis of diamond-and-inclusions associations and diamond-bearing peridotites and eclogites, follows the similar physico-chemical mechanisms (Litvin et al., 2016). This is illustrated by fractional syngenesis diagram for diamonds and associated minerals which construction is based on evidence from high pressure experiments. References Gasparik T., Litvin Yu.A (1997). Stability of Na2Mg2Si2O7 and melting relations on the forsterite - jadeite join at pressures up to 22 GPa. Eur, J. Mineral. 9(2), 311-326. Litvin Yu.A. (1991). Physico-Chemical Study of Melting of Materials from the Deep Earth. Moscow: Nauka. 312 p. Litvin Yu.A., Spivak A.V., Kuzyura A.V. (2016). Fundamentals of the mantle-carbonatite concept of diamond genesis, Geochemistry Internat. 34(10), 839-857.

Magma differentiation in volcanic conduits - the clinopyroxenite body of Fuerteventura (Canary Islands)

NASA Astrophysics Data System (ADS)

Tornare, Evelyne; Bussy, François

2014-05-01

Fractionation processes and magma differentiation/mixing occur at various levels during magma transportation through the crust. These processes are usually thought to occur in magmatic chambers or reservoirs into which magma stagnates before continuing to ascent and/or erupt. Here we discuss dynamic fractionation and magma differentiation processes in the plumbing system of an ocean island volcano. Fuerteventura, Canary Island, allows insight into the root-zone of an alkaline ocean island volcano. The PX1 pluton is a 22 Ma-old vertically layered mafic intrusion emplaced at ca. 0.1 GPa. This body shows large- and small-scale alternations of cumulate assemblages evolving from ol-rich wehrlite to clinopyroxenite to gabbro. These cumulates are intruded by numerous dykes of various compositions and veins of more evolved melt. Dykes, veins, and the large scale lithological variations define a general NNE-SSW vertical layering within the pluton. In some areas free of layering, numerous wehrlitic and clinopyroxenitic enclaves appear in a slightly more evolved matrix revealing clear mixing features of crystal mushes. Neither horizontal layering nor marginal facies are observed within PX1. Thus, clinopyroxenites do not represent accumulation of crystals through gravitational settling in a magma chamber. Compositions of cpx define a clear differentiation trend among all lithologies, from sp-bearing dunite (average cpx mg#: 85.99) to plg-ol- or kst-clinopyroxenites (mg#: 75.4). Chemically zoned cpx are present in all coarse-grained lithologies. They are characterised by a rather primitive resorbed core (higher Cr and Mg content), surrounded by a more evolved rim (higher Ti, Al and REE contents, similar to cpx in the matrix). Rims sometimes preserve clear oscillatory zoning and resorbtion features. Cores are interpreted as inherited crystals from deeper levels, whereas rims are considered to have crystallized at the final emplacement level in the root zone of the volcano. We consider clinopyroxenites to represent phenocryst concentrations left behind porphyritic basaltic magmas rising through the volcano plumbing system. Variations in the degree of differentiation and temperature of the rising magma pulses would determine which mineral phases are crystallizing at a given time during magma migration; the latter would accumulate as phenocrysts or overgrow pre-existing grains of the surrounding crystallizing mush. As long as temperature is high, only cpx will crystallize. With decreasing T, plg and kst will co-crystallize. Voluminous cpx accumulations are thus expected to develop progressively. Successive magma pulses will percolate through a porous, although increasingly crystallized mush. This would lead to overgrowth and coarsening of early-accumulated cpx phenocrysts, as well as interstitial crystallization of plg and kst when stable. Rim oscillatory zoning of cpx would record successive high-temperature magma pulses injecting and percolating though the crystal mush structure. Relatively large volumes of porphyritic basalts are requested to transit through the plumbing system of the volcano to account for the large size and coarse-grained texture of the cpx cumulates. This process is expected to generate a high-heat flow, which is consistent with the spectacular contact aureole developed around PX1, in which gabbros remelted above 1000°C (Hobson et al. J. Pet 39, 1998).

Forward modeling corona growth in a partially eclogitized leucogabbro, Bourbon Island, North-East Greenland

NASA Astrophysics Data System (ADS)

Sartini-Rideout, C.; Gilotti, J. A.; Foster, C. T.

2007-05-01

Coronitic textures are common in partially eclogitized igneous bodies, such as gabbros, leucogabbros, and anorthosites, east of the Germania Land Deformation Zone in North-East Greenland. Coronas formed by prograde metamorphic processes that transformed the gabbroic bodies to eclogite facies, and record frozen stages of the prograde metamorphic evolution of these rocks. A metaleucogabbro-norite body on Bourbon Island in Jøkelbugt is characterized by three concentric areas: a coronitic core, a mottled inner rim with areas of completely eclogitized material surrounded by a matrix of coronitic metaleucogabbro, and an outer rim of strongly foliated and completely retrogressed amphibolite. The Bourbon body preserves four stages of the prograde metamorphic history: Stage I, Stage II, Stage III, and Eclogite Stage. Stage I coronas are found only in the core of the body, which is the least reacted part of the leucogabbro-norite and the closest to the protolith, and is characterized by the corona sequence Pl rim/Grt + Kfs + Amp/Grt + Amp/Cpx rim. The typical corona sequence for Stage II is Pl rim/Grt + Pl + Zo/Cpx rim/Amp rim. Stage III samples show a Pl rim + Ky + Scp/Grt + Pl + Qtz/Qtz + Pl sequence, with the relict clinopyroxene being replaced in part by microcrystalline aggregates of Cpx + Amp + Pl. The Eclogite Stage shows relict Pl completely replaced by Grt, and the relict Cpx completely replaced by aggregates of Omp + Pl + Kfs + Amp. We tested open-system grain boundary diffusion (OSGBD) theories to model the prograde Stage I symplectitic coronas. The observed ratio of the thickness of the different layers is Pl rim:Grt + Kfs + Amp:Grt + Amp:Cpx rim equal to 3:1.3:0.95:0.5. These ratios are very close to the modeled ones of 2.7:1.1:1:0.5. Furthermore, subtle textural changes within the Grt + Kfs + Amp corona were also reproduced by the model. The model gave us insight into the conditions of the metamorphic system in which the coronas formed. The sequence Pl rim/Grt + Kfs + Amp/Grt + Amp/Cpx rim formed by diffusion driven reactions in an open system involving gain of Fe, K, and Na, and loss of Ca and Mg at the original clinopyroxene-plagioclase boundary. Relative mobilities of the different components within the corona layers were LMgMg > LAlAl > LSiSi > LCaCa > LKK > LFeFe > LNaNa. Fluid circulation was active to some degree during the transformation to eclogite. The differences between core, inner rim, and the two domains within the inner rim of the metaleucogabbro-norite can be explained by different degrees of fluid circulation in different portions of the rock. The presence of phases containing Cl and P, such as scapolite, in completely eclogitized samples supports the presence of fluid circulation in the system. Another possible explanation for the mottled appearance of the inner rim is protolith heterogeneity.

The relationship between medical students' epistemological beliefs and achievement on a clinical performance examination.

PubMed

Oh, Sun-A; Chung, Eun-Kyung; Han, Eui-Ryoung; Woo, Young-Jong; Kevin, Deiter

2016-03-01

This study was to explore the relationship between clinical performance examination (CPX) achievement and epistemological beliefs to investigate the potentials of epistemological beliefs in ill-structured medical problem solving tasks. We administered the epistemological beliefs questionnaire (EBQ) to fourth-year medical students and correlated the results with their CPX scores. The EBQ comprised 61 items reflecting five belief systems: certainty of knowledge, source of knowledge, rigidity of learning, ability to learn, and speed of knowledge acquisition. The CPX included scores for history taking, physical examination, and patient-physician interaction. The higher epistemological beliefs group obtained significantly higher scores on the CPX with regard to history taking and patient-physician interaction. The epistemological beliefs scores on certainty of knowledge and source of knowledge were significantly positively correlated with patient-physician interaction. The epistemological beliefs scores for ability to learn were significantly positively correlated with those for history taking, physical examination, and patient-physician interaction. Students with more sophisticated and advanced epistemological beliefs stances used more comprehensive and varied approaches in the patient-physician interaction. Therefore, educational efforts that encourage discussions pertaining to epistemological views should be considered to improve clinical reasoning and problem-solving competence in the clinic setting.

In-situ trace element and Sr isotopic compositions of mantle xenoliths constrain two-stage metasomatism beneath the northern North China Craton

NASA Astrophysics Data System (ADS)

Wu, Dan; Liu, Yongsheng; Chen, Chunfei; Xu, Rong; Ducea, Mihai N.; Hu, Zhaochu; Zong, Keqing

2017-09-01

Subduction and collision are the key processes triggering geochemical refertilization of the lithospheric mantle beneath cratons. However, the way that the subducted plate influences the cratonic lithospheric mantle remains unclear. Here, in-situ major and trace-element and Sr isotopic compositions of peridotite and pyroxenite xenoliths carried by the Dongbahao Cenozoic basalts, located close to the northern margin of North China Craton (NCC), were examined to investigate the effects of the subducted Paleo-Asian oceanic plate on the lithospheric mantle of the NCC. Based on petrographic and geochemical features, peridotites were subdivided into two types recording two-stage metasomatism. Clinopyroxene (Cpx) in both types of peridotites show chemical zoning. In those peridotites we refer to as Type 1 peridotites, Cpx exhibit uniform convex-upward rare earth element (REE) patterns but core-rim variations in 87Sr/86Sr ratios (0.7065-0.7082 in the cores and 0.7043-0.7059 in the spongy rims), and have high (La/Yb)N ratios (> 1.12) (N means normalized to chondrite), relatively low Ti/Eu ratios (< 3756) and negative high field strength element (HFSE) (Nb, Ta, Zr, Hf and Ti) anomalies in the cores, indicating early-stage metasomatism by carbonatitic melts derived from the subducted sedimentary carbonate rocks. Cpx in the Type 2 peridotites have highly variable REE patterns (from light rare earth element (LREE)-depleted to LREE-enriched) and feature zoned Sr isotopic compositions contrasting to those in Type 1, i.e., increasing 87Sr/86Sr ratios from the cores (0.7020-0.7031) to the spongy rims (0.7035-0.7041). Accompanying variations of 87Sr/86Sr ratios, Cpx in both types of peridotites display increasing Nb/La ratios from the cores to the spongy rims. In addition, Cpx in the Type 2 peridotites show remarkably increased (La/Yb)N, Ca/Al, Sm/Hf and Zr/Hf ratios but decreased Ti/Eu and Ti/Nb ratios from the cores to the spongy rims. These features imply a later-stage metasomatism by CO2-rich silicate melts derived from carbonated eclogites. Pyroxenites were also classified into two types. Both types of pyroxenites show higher Ni content in Cpx and orthopyroxene than peridotites at the same Mg# (= 100 ∗ Mg/(Mg + Fe), atomic number) level. Their Cpx show high Ti/Eu, Ti/Sr ratios and similar 87Sr/86Sr ratios (0.7039-0.7055) to the Cpx spongy rims in peridotites, suggesting that pyroxenites originated from silicate melt-peridotite reactions in the later-stage metasomatism. These observations collectively indicate that the lithospheric mantle beneath the northern NCC presents evidence for two distinct mantle metasomatic events. We propose that both were caused by the subduction of the Paleo-Asian oceanic plate, which could have contributed significantly to the transformation of the lithospheric mantle beneath the northern NCC.

Validity and Reproducibility of an Incremental Sit-To-Stand Exercise Test for Evaluating Anaerobic Threshold in Young, Healthy Individuals.

PubMed

Nakamura, Keisuke; Ohira, Masayoshi; Yokokawa, Yoshiharu; Nagasawa, Yuya

2015-12-01

Sit-to-stand exercise (STS) is a common activity of daily living. The objectives of the present study were: 1) to assess the validity of aerobic fitness measurements based on anaerobic thresholds (ATs), during incremental sit-to-stand exercise (ISTS) with and without arm support compared with an incremental cycle-ergometer (CE) test; and 2) to examine the reproducibility of the AT measured during the ISTSs. Twenty-six healthy individuals randomly performed the ISTS and CE test. Oxygen uptakes at the AT (AT-VO2) and heart rate at the AT (AT-HR) were determined during the ISTSs and CE test, and repeated-measures analyses of variance and Tukey's post-hoc test were used to evaluate the differences between these variables. Pearson correlation coefficients were used to assess the strength of the relationship between AT-VO2 and AT-HR during the ISTSs and CE test. Data analysis yielded the following correlations: AT-VO2 during the ISTS with arm support and the CE test, r = 0.77 (p < 0.05); AT-VO2 during the ISTS without arm support and the CE test, r = 0.70 (p < 0.05); AT-HR during the ISTS with arm support and the CE test, r = 0.80 (p < 0.05); and AT-HR during the ISTS without arm support and the CE test, r = 0.66 (p < 0.05). The AT-VO2 values during the ISTS with arm support (18.5 ± 1.9 mL·min(-1)·kg(-1)) and the CE test (18.4 ± 1.8 mL·min(-1)·kg(-1)) were significantly higher than those during the ISTS without arm support (16.6 ± 1.8 mL·min(-1)·kg(-1); p < 0.05). The AT-HR values during the ISTS with arm support (126 ± 10 bpm) and the CE test (126 ± 13 bpm) were significantly higher than those during the ISTS without arm support (119 ± 9 bpm; p < 0.05). The ISTS with arm support may provide a cardiopulmonary function load equivalent to the CE test; therefore, it is a potentially valid test for evaluating AT-VO2 and AT-HR in healthy, young adults. Key pointsThe ISTS is a simple test that varies only according to the frequency of standing up, and requires only a small space and a chair.The ISTS with arm support is valid and reproducible, and is a safe test for evaluating AT in healthy young adults.For evaluating the AT, the ISTS may serve as a valid alternative to conventional CPX, using either a cycle ergometer or treadmill, in cases where the latter methods are difficult to implement.

Paradise Lost: Uncertainties in melting and melt extraction processes beneath oceanic spreading ridges

NASA Astrophysics Data System (ADS)

Kelemen, P. B.

2014-12-01

In many ways, decompression melting and focused melt transport beneath oceanic spreading ridges is the best understood igneous process on Earth. However, there are remaining - increasing - uncertainties in interpreting residual mantle peridotites. Indicators of degree of melting in residual peridotite are questionable. Yb concentration and spinel Cr# are affected by (a) small scale variations in reactive melt transport, (b) variable extents of melt extraction, and (c) "impregnation", i.e. partial crystallization of cooling melt in pore space. Roughly 75% of abyssal peridotites have undergone major element refertilization. Many may have undergone several melting events. The following three statements are inconsistent: (1) Peridotite melt productivity beyond cpx exhaustion is > 0.1%/GPa. (2) Crustal thickness is independent of spreading rate at rates > 2 cm/yr full rate (excluding ultra-slow spreading ridges). (3) Thermal models predict, and observations confirm, thick thermal boundary layers beneath slow spreading ridges. If (a) melt productivity is << 0.1%/GPa beyond cpx-out, and (b) cpx-out occurs > 15 km below the seafloor beneath most ridges, then the independence of crustal thickness with spreading rate can be understood. Most sampled peridotites from ridges melted beyond cpx-out. Cpx in these rocks formed via impregnation and/or exsolution during cooling. Most peridotites beneath ridges may undergo cpx exhaustion during decompression melting. This would entail an upward modification of potential temperature estimates. Alternatively, perhaps oceanic crustal thickness does vary with spreading rate but this is masked by complicated tectonics and serpentinization at slow-spreading ridges. Dissolution channels (dunites) are predicted to coalesce downstream, but numerical models of these have not shown why > 95% of oceanic crust forms in a zone < 5 km wide. There may be permeability barriers guiding deeper melt toward the ridge, but field studies have not identified them. Permeable "shear bands" may guide melt to the ridge, but their nature in open systems at natural grain size and strain rates is uncertain. 2D and 3D focused solid upwelling due to melt buoyancy deep in the melting region, where pyroxenes are abundant and permeability is low, may warrant renewed attention.

Atom Probe Tomography of Phase and Grain Boundaries in Experimentally-Deformed and Hot-Pressed Wehrlite

NASA Astrophysics Data System (ADS)

Cukjati, J.; Parman, S. W.; Cooper, R. F.; Zhao, N.

2017-12-01

Atom probe tomography (APT) was used to characterize the chemistry of three grain boundaries: an olivine-olivine (ol-ol) and olivine-clinopyroxene (ol-cpx) boundary in fine-grained experimentally-deformed wehrlite and an ol-cpx boundary in a fine-grained, hot-pressed wehrlite. Grain boundaries were extracted and formed into APT tips using a focused ion beam (FIB). The tips were analyzed in a reflectron-equipped LEAP4000HR (Harvard University) at 1% or 0.5% detection rate, 5pJ laser energy and 100kHz pulse rate. Total ion counts are between 40 and 100 million per tip. Examination of grain and phase boundaries in wehrlite are of interest since slow-diffusing and olivine-incompatible cations present in cpx (e.g. Ca and Al) may control diffusion-accommodated grain boundary sliding and affect mantle rheology (Sundberg & Cooper, 2008). At steady state, ol-cpx aggregates are weaker than either ol or cpx end member, the results of which are not currently well-explained. We investigate grain boundary widths to understand the transport of olivine-incompatible elements. Widths of grain/phase boundary chemical segregation are between 3nm and 6nm for deformed ol-ol and ol-cpx samples; minimally-deformed (hot-pressed) samples having slightly wider chemical segregation widths. Chemical segregation widths were determined from profiles of Na, Al, P, Cl, K, Ca, or Ni, although not all listed elements can be used for all samples (e.g. Na, K segregation profiles can only be observed for ol-ol sample). These estimates are consistent with prior estimates of grain boundary segregation by atom probe tomography on ol-ol and opx-opx samples (Bachhav et al., 2015) and are less than ol-ol interface widths analyzed by STEM/EDX (Hiraga, Anderson, & Kohlstedt, 2007). STEM/EDX will be performed on deformed wehrlite to investigate chemical profile as a function of applied stress orientation and at length scales between those observable by APT and EPMA. Determination of phase boundary chemistry and structure allows for better modeling of the rheology of multiphase aggregates and better understanding of diffusive transport and storage of incompatible elements along grain boundaries.

Calcium isotopic composition of mantle xenoliths and minerals from Eastern China

NASA Astrophysics Data System (ADS)

Kang, Jin-Ting; Zhu, Hong-Li; Liu, Yu-Fei; Liu, Fang; Wu, Fei; Hao, Yan-Tao; Zhi, Xia-Chen; Zhang, Zhao-Feng; Huang, Fang

2016-02-01

This study presents calcium isotope data for co-existing clinopyroxenes (cpx), orthopyroxenes (opx), and olivine (ol) in mantle xenoliths to investigate Ca isotopic fractionation in the upper mantle. δ44/40Ca (δ44/40Ca (‰) = (44Ca/40Ca)SAMPLE/(44Ca/40Ca)SRM915a - 1) in opx varies from 0.95 ± 0.05‰ to 1.82 ± 0.01‰ and cpx from 0.71 ± 0.06‰ to 1.03 ± 0.12‰ (2se). δ44/40Ca in ol (P-15) is 1.16 ± 0.08‰, identical to δ44/40Ca of the co-existing opx (1.12 ± 0.09‰, 2se). The Δ44/40Caopx-cpx (Δ44/40Caopx-cpx = δ44/40Caopx-δ44/40Cacpx) shows a large variation ranging from -0.01‰ to 1.11‰ and it dramatically increases with decreasing of Ca/Mg (atomic ratio) in opx. These observations may reflect the effect of opx composition on the inter-mineral equilibrium fractionation of Ca isotopes, consistent with the theoretical prediction by first-principles theory calculations (Feng et al., 2014). Furthermore, Δ44/40Caopx-cpx decreases when temperature slightly increases from 1196 to 1267 K. However, the magnitude of such inter-mineral isotopic fractionation (1.12‰) is not consistent with the value calculated by the well-known correlation between inter-mineral isotope fractionation factors and 1/T2 (Urey, 1947). Instead, it may reflect the temperature control on crystal chemistry of opx (i.e., Ca content), which further affects Δ44/40Caopx-cpx. The calculated δ44/40Ca of bulk peridotites and pyroxenites range from 0.76 ± 0.06‰ to 1.04 ± 0.12‰ (2se). Notably, δ44/40Ca of bulk peridotites are positively correlated with CaO and negatively with MgO content. Such correlations can be explained by mixing between a fertile mantle end-member and a depleted one with low δ44/40Ca, indicating that Ca isotopes could be a useful tool in studying mantle evolution.

Characterization of the adenosine receptor in cultured embryonic chick atrial myocytes: Coupling to modulation of contractility and adenylate cyclase activity and identification by direct radioligand binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, B.T.

1989-06-01

Adenosine receptors in a spontaneously contracting atrial myocyte culture from 14-day chick embryos were characterized by radioligand binding studies and by examining the involvement of G-protein in coupling these receptors to a high-affinity state and to the adenylate cyclase and the myocyte contractility. Binding of the antagonist radioligand (3H)-8-cyclopentyl-1,3-diproylxanthine ((3H)CPX) was rapid, reversible and saturable and was to a homogeneous population of sites with a Kd value of 2.1 +/- 0.2 nM and an apparent maximum binding of 26.2 +/- 3 fmol/mg of protein (n = 10, +/- S.E.). Guanyl-5-yl-(beta, gamma-imido)diphosphate had no effect on either the Kd or themore » maximum binding and CPX reversed the N6-R-phenyl-2-propyladenosine-induced inhibition of adenylate cyclase activity and contractility, indicating that (3H) CPX is an antagonist radioligand. Competition curves for (3H) CPX binding by a series of reference adenosine agonists were consistent with labeling of an A1 adenosine receptor and were better fit by a two-site model than by a one-site model. ADP-ribosylation of the G-protein by the endogenous NAD+ in the presence of pertussis toxin shifted the competition curves from bi to monophasic with Ki values similar to those of the KL observed in the absence of prior pertussis intoxication. The adenosine agonists were capable of inhibiting both the adenylate cyclase activity and myocyte contractility in either the absence or the presence of isoproterenol. The A1 adenosine receptor-selective antagonist CPX reversed these agonist effects. The order of ability of the reference adenosine receptor agonists in causing these inhibitory effects was similar to the order of potency of the same agonists in inhibiting the specific (3H)CPX binding (N6-R-phenyl-2-propyladenosine greater than N6-S-phenyl-2-propyladenosine or N-ethyladenosine-5'-uronic acid).« less

Dysregulation of Escherichia coli α-hemolysin expression alters the course of acute and persistent urinary tract infection

PubMed Central

Nagamatsu, Kanna; Hannan, Thomas J.; Guest, Randi L.; Kostakioti, Maria; Hadjifrangiskou, Maria; Binkley, Jana; Dodson, Karen; Raivio, Tracy L.; Hultgren, Scott J.

2015-01-01

Urinary tract infections (UTIs) are among the most common bacterial infections, causing considerable morbidity in females. Infection is highly recurrent despite appropriate antibiotic treatment. Uropathogenic Escherichia coli (UPEC), the most common causative agent of UTIs, invades bladder epithelial cells (BECs) and develops into clonal intracellular bacterial communities (IBCs). Upon maturation, IBCs disperse, with bacteria spreading to neighboring BECs to repeat this cycle. This process allows UPEC to gain a foothold in the face of innate defense mechanisms, including micturition, epithelial exfoliation, and the influx of polymorphonuclear leukocytes. Here, we investigated the mechanism and dynamics of urothelial exfoliation in the early acute stages of infection. We show that UPEC α-hemolysin (HlyA) induces Caspase-1/Caspase-4–dependent inflammatory cell death in human urothelial cells, and we demonstrate that the response regulator (CpxR)-sensor kinase (CpxA) two-component system (CpxRA), which regulates virulence gene expression in response to environmental signals, is critical for fine-tuning HlyA cytotoxicity. Deletion of the cpxR transcriptional response regulator derepresses hlyA expression, leading to enhanced Caspase-1/Caspase-4– and NOD-like receptor family, pyrin domain containing 3-dependent inflammatory cell death in human urothelial cells. In vivo, overexpression of HlyA during acute bladder infection induces more rapid and extensive exfoliation and reduced bladder bacterial burdens. Bladder fitness is restored fully by inhibition of Caspase-1 and Caspase-11, the murine homolog of Caspase-4. Thus, we have discovered that fine-tuning of HlyA expression by the CpxRA system is critical for enhancing UPEC fitness in the urinary bladder. These results have significant implications for our understanding of how UPEC establishes persistent colonization. PMID:25675528

Dysregulation of Escherichia coli α-hemolysin expression alters the course of acute and persistent urinary tract infection.

PubMed

Nagamatsu, Kanna; Hannan, Thomas J; Guest, Randi L; Kostakioti, Maria; Hadjifrangiskou, Maria; Binkley, Jana; Dodson, Karen; Raivio, Tracy L; Hultgren, Scott J

2015-02-24

Urinary tract infections (UTIs) are among the most common bacterial infections, causing considerable morbidity in females. Infection is highly recurrent despite appropriate antibiotic treatment. Uropathogenic Escherichia coli (UPEC), the most common causative agent of UTIs, invades bladder epithelial cells (BECs) and develops into clonal intracellular bacterial communities (IBCs). Upon maturation, IBCs disperse, with bacteria spreading to neighboring BECs to repeat this cycle. This process allows UPEC to gain a foothold in the face of innate defense mechanisms, including micturition, epithelial exfoliation, and the influx of polymorphonuclear leukocytes. Here, we investigated the mechanism and dynamics of urothelial exfoliation in the early acute stages of infection. We show that UPEC α-hemolysin (HlyA) induces Caspase-1/Caspase-4-dependent inflammatory cell death in human urothelial cells, and we demonstrate that the response regulator (CpxR)-sensor kinase (CpxA) two-component system (CpxRA), which regulates virulence gene expression in response to environmental signals, is critical for fine-tuning HlyA cytotoxicity. Deletion of the cpxR transcriptional response regulator derepresses hlyA expression, leading to enhanced Caspase-1/Caspase-4- and NOD-like receptor family, pyrin domain containing 3-dependent inflammatory cell death in human urothelial cells. In vivo, overexpression of HlyA during acute bladder infection induces more rapid and extensive exfoliation and reduced bladder bacterial burdens. Bladder fitness is restored fully by inhibition of Caspase-1 and Caspase-11, the murine homolog of Caspase-4. Thus, we have discovered that fine-tuning of HlyA expression by the CpxRA system is critical for enhancing UPEC fitness in the urinary bladder. These results have significant implications for our understanding of how UPEC establishes persistent colonization.

Identification of Two New HIV-1 Circulating Recombinant Forms (CRF87_cpx and CRF88_BC) from Reported Unique Recombinant Forms in Asia.

PubMed

Hu, Yihong; Wan, Zhenzhou; Zhou, Yan-Heng; Smith, Davey; Zheng, Yong-Tang; Zhang, Chiyu

2017-04-01

The on-going generation of HIV-1 intersubtype recombination has led to new circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in Asia. In this study, we evaluated whether previously reported URFs were actually CRFs. All available complete or near full-length HIV-1 URF sequences from Asia were retrieved from the HIV Los Alamos National Laboratory Sequence database, and phylogenetic, transmission cluster, and bootscan analyses were performed using MEGA 6.0, Cluster Picker 1.2.1, and SimPlot3.5.1. According to the criterion of new CRFs, two new HIV-1 CRFs (CRF87_cpx and CRF88_BC) were identified from these available URFs. CRF87_cpx comprised HIV-1 subtypes B, C, and CRF01_AE, and CRF88_BC comprised subtypes B and C. HIV Blast and bootscan analysis revealed that besides the three representative strains, there were two additional CRF87_cpx strains. Furthermore, we defined seven dominant URFs (dURF01-dURF07), each of which contained two strains sharing same recombination map and can be used as sequence references to facilitate the finding of new potential CRFs in future. These results will benefit the molecular epidemiological investigation of HIV-1 in Asia.

Relationship between aerobic capacity and pelvic floor muscles function: a cross-sectional study

PubMed Central

Jürgensen, S.P.; Borghi-Silva, A.; Bastos, A.M.F.G.; Correia, G.N.; Pereira-Baldon, V.S.; Cabiddu, R.; Catai, A.M.; Driusso, P.

2017-01-01

The objective of this study was to evaluate the relationship between aerobic capacity and pelvic floor muscles (PFM) function in adult women. Women aged 18 or over and without urinary dysfunction or other chronic diseases were eligible to participate. They completed the habitual physical activity (HPA) questionnaire, underwent a PFM functional evaluation by palpation and perineometry, and performed a submaximal (between 75 and 85% of maximum heart rate) cardiopulmonary exercise (CPX) test to determine the ventilatory anaerobic threshold (VAT). Forty-one women were included (35±16 years, 75% physically active, 17% very active, and 8% sedentary and 17% presented grade 1 PFM contraction, 31.8% grade 2, 26.8% grade 3, and 24.4% grade 4, according to the modified Oxford Scale). The average PFM contraction pressure obtained by perineometer was 53±26 cmH2O and the average oxygen consumption at VAT (VO2VAT) obtained from CPX was 14±2 mL·kg-1·min-1. Significant correlations were found between PFM contraction pressure and VO2VAT (r=0.55; P<0.001); between PFM contraction pressure and HPA score (r=0.38; P=0.02); between age and VO2VAT (r=-0.25; P=0.049); and between VO2VAT and HPA score (r=0.36; P=0.02). An age-adjusted multiple linear regression equation (R2=0.32) was derived to estimate VO2VAT from the contraction value obtained by perineometer, so that the PFM contraction pressure was able to predict VO2VAT. The equation was validated using data from another group of 20 healthy women (33±12 years; PFM contraction: 49±23 cmH2O) and no significant difference was found between actual VO2VAT and predicted VO2VAT (13.1±1.9 vs 13.8±2.0 mL·kg-1·min-1). In conclusion, PFM function is associated with aerobic capacity in healthy women and PFM contraction pressure may be used to estimate VO2VAT in this population. PMID:28953985

Design of liposomal colloidal systems for ocular delivery of ciprofloxacin

PubMed Central

Taha, Ehab I.; El-Anazi, Magda H.; El-Bagory, Ibrahim M.; Bayomi, Mohsen A.

2013-01-01

Ophthalmic drug bioavailability is limited due to protective mechanisms of the eye which require the design of a system to enhance ocular delivery. In this study several liposomal formulations containing ciprofloxacin (CPX) have been formulated using reverse phase evaporation technique with final dispersion of pH 7.4. Different types of phospholipids including Phosphatidylcholine, Dipalmitoylphosphatidylcholine and Dimyristoyl-sn-glycero-3-phosphocholine were utilized. The effect of formulation factors such as type of phospholipid, cholesterol content, incorporation of positively charging inducing agents and ultrasonication on the properties of the liposomal vesicles was studied. Bioavailability of selected liposomal formulations in rabbit eye aqueous humor has been investigated and compared with that of commercially available CPX eye drops (Ciprocin®). Pharmacokinetic parameters including Cmax, Tmax, elimination rate constant, t1/2, MRT and AUC0–∞, were determined. The investigated formulations showed more than three folds of improvement in CPX ocular bioavailability compared with the commercial product. PMID:25061409

The Paradox of a Wet (High H2O) and Dry (Low H2O/Ce) Mantle: High Water Concentrations in Mantle Garnet Pyroxenites from Hawaii

NASA Technical Reports Server (NTRS)

Peslier, Anne H.; Bizimis, Michael

2013-01-01

Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of Mid-Ocean Ridge Basalt (MORB) and Oceanic Island Basalt (OIB). but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. Here, we analyzed by FTIR water in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than cpx/opx equilibrium from experimental data. The pyroxenite cpx and opx H2O concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (<5ppm H2O). There is no correlation between H2O in cpx and lithophile element concentrations. Phlogopite is present in some samples, and its modal abundance shows a positive correlation in Mg# with cpx, implying equilibrium. However, there is no correlation between H2O concentrations and or the presence of phlogopite. These data imply that cpx and opx may be at water saturation, far lower than experimental data suggest. Reconstructed bulk rock pyroxenite H2O ranges from 200-460 ppm (average 331 +/- 75 ppm), 2 to 8 times higher than H2O estimates for the MORB source (50-200 ppm), but in the range of E-MORB, OIB and the source of rejuvenated Hawaiian magmas. The average bulk rock pyroxenite H2O/Ce is 69 +/-35, lower than estimates of the MORB source (approx 150) or FOZO, C (200-250) mantle component, but consistent with "dry" EM sources (<100). These data suggest that a metasomatized, refertilized oceanic lithosphere that contains pyroxenitic veins (e.g. the lower part of an oceanic plate, where ascending melts can become trapped and crystallize), will have both higher water concentrations and low H2O/Ce, and may contribute to EM-type OIB sources, like that of Samoa basalts. Therefore, a low H2O/Ce mantle source may not necessarily be "dry".

Legionella pneumophila OxyR Is a Redundant Transcriptional Regulator That Contributes to Expression Control of the Two-Component CpxRA System.

PubMed

Tanner, Jennifer R; Patel, Palak G; Hellinga, Jacqueline R; Donald, Lynda J; Jimenez, Celine; LeBlanc, Jason J; Brassinga, Ann Karen C

2017-03-01

Nominally an environmental organism, Legionella pneumophila is an intracellular parasite of protozoa but is also the causative agent of the pneumonia termed Legionnaires' disease, which results from inhalation of aerosolized bacteria by susceptible humans. Coordination of gene expression by a number of identified regulatory factors, including OxyR, assists L. pneumophila in adapting to the stresses of changing environments. L. pneumophila OxyR (OxyR Lp ) is an ortholog of Escherichia coli OxyR; however, OxyR Lp was shown elsewhere to be functionally divergent, such that it acts as a transcription regulator independently of the oxidative stress response. In this study, the use of improved gene deletion methods has enabled us to generate an unmarked in-frame deletion of oxyR in L. pneumophila Lack of OxyR Lp did not affect in vitro growth or intracellular growth in Acanthamoeba castellanii protozoa and U937-derived macrophages. The expression of OxyR Lp does not appear to be regulated by CpxR, even though purified recombinant CpxR bound a DNA sequence similar to that reported for CpxR elsewhere. Surprisingly, a lack of OxyR Lp resulted in elevated activity of the promoters located upstream of icmR and the lpg1441-cpxA operon, and OxyR Lp directly bound to these promoter regions, suggesting that OxyR Lp is a direct repressor. Interestingly, a strain overexpressing OxyR Lp demonstrated reduced intracellular growth in A. castellanii but not in U937-derived macrophages, suggesting that balanced expression control of the two-component CpxRA system is necessary for survival in protozoa. Taken together, this study suggests that OxyR Lp is a functionally redundant transcriptional regulator in L. pneumophila under the conditions evaluated herein. IMPORTANCE Legionella pneumophila is an environmental pathogen, with its transmission to the human host dependent upon its ability to replicate in protozoa and survive within its aquatic niche. Understanding the genetic factors that contribute to L. pneumophila survival within each of these unique environments will be key to limiting future point-source outbreaks of Legionnaires' disease. The transcriptional regulator L. pneumophila OxyR (OxyR Lp ) has been previously identified as a potential regulator of virulence traits warranting further investigation. This study demonstrated that oxyR is nonessential for L. pneumophila survival in vitro and in vivo via mutational analysis. While the mechanisms of how OxyR Lp expression is regulated remain elusive, this study shows that OxyR Lp negatively regulates the expression of the cpxRA two-component system necessary for intracellular survival in protozoa. Copyright © 2017 American Society for Microbiology.

Sm-Nd Age and Nd- and Sr- Isotopic Evidence for the Petrogenesis of Dhofar 378

NASA Technical Reports Server (NTRS)

Nyquist, L. E.; Ikeda, Y.; Shih, C.-Y.; Reese, Y. D.; Nakamura, N.; Takeda, H.

2006-01-01

Dhofar 378 (hereafter Dho 378) is one of the most ferroan lithologies among martian meteorites, resembling the Los Angeles basaltic shergottite in lithology and mineral chemistry, although it is more highly shocked than Los Angeles. All plagioclase (Pl) grains in the original lithology were melted by an intense shock in the range 55-75 GPa. Clinopyroxenes (Cpx) sometimes show mosaic extinction under a microscope showing that they, too, experienced intense shock. Nevertheless, they zone from magnesian cores to ferroan rims, reflecting the original lithology. Cpx grains also often contain exsolution lamellae, showing that the original lithology cooled slowly enough for the lamellae to form. Because all plagioclase grains were melted by the intense shock and subsequently quenched, the main plagioclase component is glass (Pl-glass) rather than maskelynite. Like Los Angeles, but unlike most basaltic shergottites, Dho 378 contains approximately equal modal abundances of Cpx and Pl-glass. The grain sizes of the original minerals were comparatively large (approximately 1 mm). The original plagioclase zoning has been severely modified. Following shock melting, the plagioclase melts crystallized from the outside inward, first forming outer rims of Cpx-Pl intergrowths (approximately 10 micrometers) followed by inner rims (10's to 100 micrometers) of An(sub 40-50) feldspar, and finally Pl-gl cores of compositions An(sub 33-50) with orthoclase compositions up to Or(sub 12).

Clinopyroxene Diffusion Chronometry of the Scaup Lake Rhyolite, Yellowstone Caldera, WY

NASA Astrophysics Data System (ADS)

Brugman, K. K.; Till, C. B.; Bose, M.

2016-12-01

Eruption of the Scaup Lake flow (SCL) ended 220,000 years of dormancy and began the youngest sequence of eruptions at Yellowstone caldera [Christiansen et al., USGS, 2007]. Quantification of the time intervals between magmatic events and eruption recorded in SCL is critical to interpreting signs of unrest at modern-day Yellowstone. SCL rhyolite includes zoned phenocrysts and accessory phases that indicate multiple rejuvenation events occurred shortly before eruption; previous studies focused on feldspar and zircon crystal records [e.g. Bindeman et al., J.Pet, 2008; Till et al., Geology, 2015]. Here we exploit zoned clinopyroxene (cpx)—one of the earliest-crystalized minerals in SCL as indicated by petrographic relationships—as a diffusion dating tool and utilize elements with different diffusivities to more precisely resolve rejuvenation-eruption timescales. Using NanoSIMS concentration profiles with 300-900 nanometer spacing, we employ the slower-diffusing REE Ce as a proxy for the initial profile shape of faster-diffusing Fe to calculate diffusive timescales. The outermost resolvable zone boundary in SCL cpx yields a rejuvenation-eruption timescale of 166 ± 80 yrs (1 SD). In comparison, modeling relaxation of Fe from a step function initial condition at the same temperature (920°C) yields a less precise timescale of 488 +9000 -300 yrs. Examination of our results, in concert with observed petrographic relationships, indicates SCL cpx may record an older, separate rejuvenation event than those recorded in feldspar rims at < 10 months and 10-40 years prior to eruption [Till et al., Geology, 2015]. The difference in the youngest recorded event between feldspar and cpx may be due to different crystallization intervals for these phases and/or slower crystal growth rates for cpx relative to feldspar. Our diffusion modeling results reinforce that intracrystalline zoning timescales modeled using a step function initial condition should be considered maxima, especially in viscous rhyolitic magmas, and that different phases may not record the same series of pre-eruptive events due to differences in crystallization behavior.

Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism

USGS Publications Warehouse

Fodor, R.V.; Moore, R.B.

1994-01-01

The 1960 Kapoho lavas of Kilauea's east rift zone contain 1-10 cm xenoliths of olivine gabbro, olivine gabbro-norite, and gabbro norite. Textures are poikilitic (ol+sp+cpx in pl) and intergranular (cpx+pl??ol??opx). Poikilitic xenoliths, which we interpret as cumulates, have the most primitive mineral compositions, Fo82.5, cpx Mg# 86.5, and An80.5. Many granular xenoliths (ol and noritic gabbro) contain abundant vesicular glass that gives them intersertal, hyaloophitic, and overall 'open' textures to suggest that they represent 'mush' and 'crust' of a magma crystallization environment. Their phase compositions are more evolved (Fo80-70, cpx Mg# 82-75, and An73-63) than those of the poikilitic xenoliths. Associated glass is basaltic, but evolved (MgO 5 wt%; TiO2 3.7-5.8 wt%). The gabbroic xenolith mineral compositions fit existing fractional crystallization models that relate the origins of various Kilauea lavas to one another. FeO/MgO crystal-liquid partitioning is consistent with the poikilitic ol-gabbro assemblage forming as a crystallization product from Kilauea summit magma with ???8 wt% MgO that was parental to evolved lavas on the east rift zone. For example, least squares calculations link summit magmas to early 1955 rift-zone lavas (???5 wt% MgO) through ???28-34% crystallization of the ol+sp+cpx+pl that comprise the poikilitic ol-gabbros. The other ol-gabbro assemblages and the olivine gabbro-norite assemblages crystallized from evolved liquids, such as represented by the early 1955 and late 1955 lavas (???6.5 wt% MgO) of the east rift zone. The eruption of 1960 Kapoho magmas, then, scoured the rift-zone reservoir system to entrain portions of cumulate and solidification zones that had coated reservoir margins during crystallization of prior east rift-zone magmas. ?? 1994 Springer-Verlag.

Rodingitization and hydration of the oceanic lithosphere as developed in the Leka ophiolite, north central Norway

NASA Astrophysics Data System (ADS)

Austrheim, H.; Prestvik, T.

2008-08-01

Ophiolite complexes in mountain chains may give supplementary information on the hydration of the oceanic lithosphere to that obtained from dredged and drilled samples from the ocean floor. The ultramafic (mantle) and the layered ultramafic to anorthositic (crustal) sequences of the Cambrian (497 Ma) Leka ophiolite are variably serpentinized and chloritized. Grossular-rodingite (rodingite s.s.) has been found over a c.500 m long and tens of meters wide zone in the layered, crustal section of the complex and is developed in both pyroxenites and gabbro/anorthosite layers. Shear zones and meter wide fracture zones, where the rock has developed a fracture cleavage, are oriented at high angel to the layering and these zones were the main conduits for transport of fluid and solute between the various lithologies. Some 5-15 cm thick layers of anorthosite (or leucogabbro) have been rodingitized around such a fractures zone, with the development of three distinct metasomatic zones along the plagioclase layer. A central grossular-dominated zone with clinopyroxene, clinozoisite, prehnite, chlorite and minor titanite (rodingite zone) extends for up to 3 m along strike and gives way to a clinozoisite-dominated zone (typically 0.5 m wide) with additional grossular, clinopyroxene and chlorite which is followed outward by a LILE-enriched zone (LILE-zone) with clinozoisite, phlogopite, K-feldspar, plagioclase and preiswerkite. The LILE-zone extends more than 3 m out from the clinozoisite-dominated zone (Clz-zone). Assuming constant volume, the rodingite formed from the plagioclase layer by addition of 20 g of CaO per 100 g of rock. All Na 2O (c. 2 g) was removed from both rodingite- and Clz-zones. Ti and V increase almost 10× in the rodingite compared to its protolith. K, Ba, Rb and Cs are strongly enriched in the LILE-zone compared to the protolith and suggest interaction with sea water. The lithologies alternating with the plagioclase layers (clinopyroxenite, wehrlite, websterite and dunite) display textures indicating a number of Ca-releasing (Cpx → Chl, Cpx → Srp, Cpx → Amph) and Ca-consuming (Opx → Cpx2, Ol → Cpx2, Cpx1 → Cpx2) reactions. The replacement textures are distributed around fracture and shear zones, with the Ca -releasing reactions in the core and the Ca -consuming reactions in distal parts, forming a metasomatic column out from the fluid pathways. Serpentinization and chloritization of clinopyroxene was the main Ca-source for the rodingitization process. This first description of rodingite in a layered sequence of an ophiolite complex indicates that the hydration of the oceanic lithosphere occurred at various structural levels and was associated with Ca-metasomatism also in places where rodingite s.s. is lacking. The different lithologies exchanged elements through transport on shear and fracture zones.

The paradox of a wet (high H2O) and dry (low H2O/Ce) mantle: High water concentrations in mantle garnet pyroxenites from Hawaii

NASA Astrophysics Data System (ADS)

Bizimis, M.; Peslier, A. H.

2013-12-01

Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of MORB and OIB [1], but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. We analyzed by FTIR water concentrations in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt. H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than experimental cpx/opx equilibrium data. These pyroxenite cpx and opx water concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and megacrysts from kimberites [2] and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (<5ppm H2O). There is no correlation between water in cpx and lithophile element concentrations. Phlogopite is present in some samples, and its modal abundance shows a positive correlation in Mg# with cpx, implying equilibrium. However, there is no correlation between water concentrations and the presence of phlogopite. These data imply that cpx and opx water concentrations may be buffered by phlogopite crystallization. Reconstructed bulk rock pyroxenite water concentrations (not including phlogopite, i.e. minimum) range from 200-460 ppm (average 331× 75 ppm), significantly higher than water estimates for the MORB source (50-200 ppm), but in the range of E-MORB, OIB and the source of rejuvenated Hawaiian magmas [1,3]. The average bulk rock pyroxenite H2O/Ce is 69 × 35, lower than estimates of the MORB source (~150) or FOZO, C (200-250) mantle component, but consistent with 'dry' EM sources (<100) [1]. These data suggest that a metasomatized, refertilized oceanic lithosphere that contains a pyroxenite component (e.g. in the lower part of an oceanic plate, where ascending melts can become trapped and crystallize), will have both higher water concentrations and low H2O/Ce, and may contribute to EM-type OIB sources, like that of Samoan basalts [5]. Therefore, a low H2O/Ce mantle source may not necessarily be 'dry'. [1] Dixon et al., 2002, Nature 420, 385-389. [2] Peslier, 2010 JVGR 197, 239-258. [3] Dixon et al., 1997 JP 38, 911-939. [4] O'Leary et al. 2010 EPSL 297, 111-120. [5] Workman et al., 2006 EPSL 241, 932 - 951.

Transmitted drug resistance is still low in newly diagnosed human immunodeficiency virus type 1 CRF06_cpx-infected patients in Estonia in 2010.

PubMed

Avi, Radko; Huik, Kristi; Pauskar, Merit; Ustina, Valentina; Karki, Tõnis; Kallas, Eveli; Jõgeda, Ene-Ly; Krispin, Tõnu; Lutsar, Irja

2014-03-01

The presence of transmitted drug resistance (TDR) in treatment-naive HIV-1-positive subjects is of concern, especially in the countries of the former Soviet Union in which the number of subjects exposed to antiretrovirals (ARV) has exponentially increased during the past decade. We assessed the rate of TDR among newly diagnosed subjects in Estonia in 2010 and compared it to that in 2008. The study included 325 subjects (87% of all subjects tested HIV positive from January 1 to December 31, 2010). Of the 244 sequenced viral genomic RNA in the reverse transcriptase (RT) region 214 were CRF06_cpx, nine were subtype A1, three (one each) were subtype B and subtype C, CRF02_AG, and CRF03_AB; 15 viruses remained unclassified as putative recombinant forms between CRF06_cpx and subtype A1. HIV-1 TDR mutations in 2010 and 2008 (n=145) occurred at similar frequency in 4.5% (95% CI 2.45; 7.98) and 5.5% (95% CI 1.8; 9.24) of the patients, respectively. In 2010, 2.5% (6/244) of the sequences harbored nonnucleoside reverse transcriptase inhibitor (NNRTI) (K103N and K101E), 1.6% (4/244) nucleoside reverse transcriptase inhibitor (NRTI) (M41L, M184I, and K219E), and 0.4% (1/244) protease inhibitor (PI) (V82A) mutations. Our findings indicate that in spite of the increased consumption of ARVs the rate of TDR in Estonia has remained unchanged over the past 3 years. Similar stabilizing or even decreasing trends have been described in Western Europe and North America albeit at higher levels and in different socioeconomic backgrounds.

Genetic Diversity of HIV-1 in Tunisia.

PubMed

El Moussi, Awatef; Thomson, Michael M; Delgado, Elena; Cuevas, María Teresa; Nasr, Majda; Abid, Salma; Ben Hadj Kacem, Mohamed Ali; Benaissa Tiouiri, Hanene; Letaief, Amel; Chakroun, Mohamed; Ben Jemaa, Mounir; Hamdouni, Hayet; Tej Dellagi, Rafla; Kheireddine, Khaled; Boutiba, Ilhem; Pérez-Álvarez, Lucía; Slim, Amine

2017-01-01

In this study, the genetic diversity of HIV-1 in Tunisia was analyzed. For this, 193 samples were collected in different regions of Tunisia between 2012 and 2015. A protease and reverse transcriptase fragment were amplified and sequenced. Phylogenetic analyses were performed through maximum likelihood and recombination was analyzed by bootscanning. Six HIV-1 subtypes (B, A1, G, D, C, and F2), 5 circulating recombinant forms (CRF02_AG, CRF25_cpx, CRF43_02G, CRF06_cpx, and CRF19_cpx), and 11 unique recombinant forms were identified. Subtype B (46.4%) and CRF02_AG (39.4%) were the predominant genetic forms. A group of 44 CRF02_AG sequences formed a distinct Tunisian cluster, which also included four viruses from western Europe. Nine viruses were closely related to isolates collected in other African or in European countries. In conclusion, a high HIV-1 genetic diversity is observed in Tunisia and the local spread of CRF02_AG is first documented in this country.

Combined Dietary Nitrate and Exercise Intervention in Peripheral Artery Disease: Protocol Rationale and Design

PubMed Central

Woessner, Mary N; VanBruggen, Mitch D; Pieper, Carl F; O'Reilly, Erin K; Kraus, William E

2017-01-01

Background Peripheral artery disease (PAD) is caused by atherosclerotic occlusions in the legs. It affects approximately 8-12 million people in the United States alone, one-third of whom suffer from intermittent claudication (IC), defined as ischemic leg pain that occurs with walking and improves with rest. Patients with IC suffer a markedly impaired quality of life and a high perception of disability. Improving pain-free walking time is a primary goal of rehabilitation in this population. Objective The nitric oxide (NO)-PAD trial is designed to compare the effects that 12 weeks of supervised exercise training, in combination with a high inorganic nitrate-content (beetroot [BR] juice) beverage or placebo (PL) beverage, has on clinical outcomes of exercise and functional capacity in two groups of PAD+IC patients: exercise training plus beetroot (EX+BR) and exercise training plus placebo (EX+PL). The primary aims of this randomized controlled, double-blind pilot study are to determine group differences following 12 weeks of EX+BR versus EX+PL in the changes for (1) exercise capacity: pain-free walking time (claudication onset time, COT), peak walk time (PWT), and maximal exercise capacity (peak oxygen uptake, VO2peak) during a maximal-graded cardiopulmonary exercise test (max CPX) and (2) functional capacity: 6-minute walk (6MW) distance. The secondary aims will provide mechanistic insights into the exercise outcome measures and will include (1) gastrocnemius muscle oxygenation during exercise via near-infrared spectroscopy (NIRS); (2) gastrocnemius muscle angiogenesis: capillaries per unit area and per muscle fiber, and relative fraction of type I, IIa, IIb, and IId/x fibers; and (3) vascular health/function via brachial artery flow-mediated dilation, lower-limb blood flow via plethysmography, and pulse wave velocity and reflection. Methods A total of 30 subjects between 40 and 80 years of age with PAD who are limited by IC will undergo exercise training 3 days per week for 12 weeks (ie, 36 sessions). They will be randomized to either the EX+BR or EX+PL group where participants will consume a beverage high in inorganic nitrate (4.2 mmol) or a low-nitrate placebo, respectively, 3 hours prior to each training session. Results Data collection from this study has been completed and is in the process of analysis and write-up. While the study is too underpowered—EX+BR, n=11; EX+PL, n=13—to determine between-group differences in the primary outcomes of COT, PWT, and 6MW, preliminary observations are promising with Cohen d effect sizes of medium to large. Conclusions Exercise training is currently the most effective therapy to increase functional capacity in PAD+IC. If the addition of inorganic nitrate to an exercise regimen elicits greater benefits, it may redefine the current standard of care for PAD+IC. Trial Registration ClinicalTrials.gov NCT01684930; https://clinicaltrials.gov/ct2/show/NCT01684930 (Archived by WebCite at http://www.webcitation.org/6raXFyEcP) PMID:28974486

Refined mapping and YAC contig construction of the X-linked cleft palate and ankyloglossia locus (CPX) including the proximal X-Y homology breakpoint within Xq21.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forbes, S.A.; Brennan, L.; Richardson, M.

1996-01-01

The gene for X-linked cleft palate (CPX) has previously been mapped in an Icelandic kindred between the unordered proximal markers DXS1002/DXS349/DXS95 and the distal marker DXYS1X, which maps to the proximal end of the X-Y homology region in Xq21.3. Using six sequence-tagged sites (STSs) within the region, a total of 91 yeast artificial chromosome (YAC) clones were isolated and overlapped in a single contig that spans approximately 3.1 Mb between DXS1002 and DXYS1X. The order of microsatellite and STS markers in this was established as DXS1002-DXS1168-DXS349-DXS95-DXS364-DXS1196-DXS472-DXS1217-DXYS1X. A long-range restriction map of this region was created using eight nonchimeric, overlapping YACmore » clones. Analysis of newly positioned polymorphic markers in recombinant individuals from the Icelandic family has enabled us to identify DXS1196 and DXS1217 as the flanking markers for CPX. The maximum physical distance containing the CPX gene has been estimated to be 2.0 Mb, which is spanned by a minimum set of five nonchimeric YAC clones. In addition, YAC end clone and STS analyses have pinpointed the location of the proximal boundary of the X-Y homology region within the map. 40 refs., 2 figs., 2 tabs.« less

The expression of Longus type 4 pilus of enterotoxigenic Escherichia coli is regulated by LngR and LngS and by H-NS, CpxR and CRP global regulators.

PubMed

De la Cruz, Miguel A; Ruiz-Tagle, Alejandro; Ares, Miguel A; Pacheco, Sabino; Yáñez, Jorge A; Cedillo, Lilia; Torres, Javier; Girón, Jorge A

2017-05-01

Enterotoxigenic Escherichia coli produces a long type 4 pilus called Longus. The regulatory elements and the environmental signals controlling the expression of Longus-encoding genes are unknown. We identified two genes lngR and lngS in the Longus operon, whose predicted products share homology with transcriptional regulators. Isogenic lngR and lngS mutants were considerably affected in transcription of lngA pilin gene. The expression of lngA, lngR and lngS genes was optimally expressed at 37°C at pH 7.5. The presence of glucose and sodium chloride had a positive effect on Longus expression. The presence of divalent ions, particularly calcium, appears to be an important stimulus for Longus production. In addition, we studied H-NS, CpxR and CRP global regulators, on Longus expression. The response regulator CpxR appears to function as a positive regulator of lng genes as the cpxR mutant showed reduced levels of lngRSA expression. In contrast, H-NS and CRP function as negative regulators since expression of lngA was up-regulated in isogenic hns and crp mutants. H-NS and CRP were required for salt- and glucose-mediated regulation of Longus. Our data suggest the existence of a complex regulatory network controlling Longus expression, involving both local and global regulators in response to different environmental signals. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

[Calciphylaxis in dialysis patients: To recognize and treat it as soon as possible].

PubMed

Jean, Guillaume; Terrat, Jean-Claude; Vanel, Thierry; Hurot, Jean-Marc; Lorriaux, Christie; Mayor, Brice; Chazot, Charles

2010-11-01

Calciphylaxis (CPX) or calcific uraemic arteriolopathy is a rare life-threatening complication, affecting mainly dialysis patients. The condition is characterized by calcifications and thrombosis of the small cutaneous vessels and small vessels in the fat tissue, resulting in the development of necrotizing and non-healing ulcers. The development of these lesions leads to poor outcomes owing to infectious complications and some frequently associated unfavourable medical conditions: obesity, diabetes, and peripheral vascular disease. We report the case of six patients with different clinical forms of CPX in the past 10 years with favourable outcomes observed in five of the six patients. The diagnosis was based on clinical presentation: bilateral and hyperalgesic necrotic lesions along with a history of mineral metabolism disorder or warfarin use. The therapeutic strategy included the following: daily dialysis, hyperbaric oxygen therapy, treatment of limb artery stenosis, maintenance of the optimal haemodynamic stability, delivery of cutaneous care, administration of analgesics and antibiotics, warfarin and calcium cessation, and additional therapy with cinacalcet or parathyroidectomy and therapy with bisphosphonates or sodium thiosulphate. Healing was observed in five out of six CPX patients by using this strategy that should be rapidly employed in order to decrease the necrotizing areas that result in poor outcomes. Prevention includes identification of at-risk patients in order to optimize the treatment of the identified risk factors for CPX. Copyright © 2010 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Physiology, pathogenicity and immunogenicity of live, attenuated Salmonella enterica serovar Enteritidis mutants in chicks.

PubMed

Si, Wei; Wang, Xiumei; Liu, Huifang; Yu, Shenye; Li, Zhaoli; Chen, Liping; Zhang, Wanjiang; Liu, Siguo

2015-01-01

To construct a novel live, attenuated Salmonella vaccine, the lon, cpxR and cpdB genes were deleted from a wild-type Salmonella enterica serovar Enteritidis-6 (SM-6) strain using the phage λ Red homologous recombination system, resulting in SM-△CpxR, SM-△C/Lon and SM-△C/L/CpdB. The growth curves of strain SM-△C/Lon grew more rapidly than the other strains and had OD 600 values higher than the other strains starting at the 4 h time point. The growth curves of strain SM-△C/L/CpdB were relatively flat. The colonization time of SM-△C/L/CpdB is about 8-10 days. Deleting the lon/cpxR/cpdB (SM-6) genes resulted in an approximate 10(3)-fold attenuation in virulence assessed by the analysis of the LD50 of specific pathogen-free (SPF) chicks. This result indicated that the deletion of the lon, cpxR and cpdB genes induced significant virulence attenuation. The protective effects of SM-△C/L/CpdB vaccination in SPF chicks against 5 × 10(9) colony forming units (CFU) of S. Enteritidis were resulted from the induction of an effective immune response. These findings demonstrate the potential of mutant SM-△C/L/CpdB to be used as an effective vaccine. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mt. Etna plumbing system revealed by combined textural, compositional, and thermobarometric studies in clinopyroxenes

NASA Astrophysics Data System (ADS)

Giacomoni, P. P.; Coltorti, M.; Bryce, J. G.; Fahnestock, M. F.; Guitreau, M.

2016-04-01

Coupled textural and in situ geochemical studies of clinopyroxene (cpx) phenocrysts, from both historical and recent eruptions of Mt. Etna volcano, provide a means to investigate the processes occurring in the deepest portion of the feeding system (>10 km depth). Five distinct textures were recognized: (1) normal oscillatory zoning, (2) normal zoning with Fe-rich rim, (3) sieve-textured core, (4) reverse oscillatory zoning, and (5) dusty rim. Electron microprobe analyses indicate an almost constant diopside-augite composition, with a slight enrichment in the enstatite for more recent erupted cpx. Core-to-rim compositional profiles, performed along the cpx, reveal distinct compositional characteristics. Normal oscillatory zoning is often characterized by a sharp increase in FeO (Δ ~ 2 wt%) accompanied by a drop in Al2O3 on the outermost 30 μm. Reverse oscillatory zoning, by contrast, exhibits a drop in FeO, Al2O3 (Δ ~ 2 wt%), and a remarkable crystal rim increase in MgO (up to 5 wt%). Similar compositional changes are evident in dusty-textured rims, which are characterized by dissolution edges and overgrowth containing glass pockets and channels. No significant compositional variations have been observed across crystals with sieve-textured cores. Trace element concentrations show enrichments in Sr, La, Zr, and REE, together with a decreasing La/Yb ratio (from ~7 to ~4) in rims of normally zoned crystals. Cpx with reverse zoning and dusty rims has low Sr, La, Zr, and REE contents toward crystal rims. Thermometers and barometers, based on equilibrium cpx-melt pairs, suggest that cpx cores start nucleating at 720 MPa, with the majority of them forming between 600 and 400 MPa but continuing to crystallize until very shallow depths (<100 MPa). Normal oscillatory-zoned phenocrysts surrounded by rims form at pressures shallower than 400 MPa, while reverse zoning and dusty rims occur between 400 and 500 MPa. Coupled petrologic and thermobarometric studies on both clinopyroxenes and plagioclases, associated with detailed textural and in situ geochemical analyses, are promising tools to reconstruct the entire magma ascent path beneath open-system volcanoes. At Mt. Etna, two distinct processes could account for the observed textures: Fe-rich rims in normal oscillatory-zoned crystals can be related to decompression-induced crystallization, while reverse zoning and dusty rims can be produced by mixing with a more basic magma at 400-500 MPa (i.e., ~10 km). Textural features are not restricted to a particular evolutionary phase of the volcano, which suggest that the deep feeding system has not changed significantly since the first alkaline volcanic phase.

Mafic/Ultramafic xenoliths from Saurashtra peninsula of Gujarat; northwestern Deccan Trap, India

NASA Astrophysics Data System (ADS)

Naushad, M.; Behera, J. R.; Chakra, M.; Murthy, P. V.

2017-12-01

The crustal growth forming processes at the crust-mantle interface or within the crust due to magma underplating is important for the formation and emplacement of continental flood basalt and large igneous provinces. Mafic/ultramafic xenoliths from lower crust or upper mantle provide clue to characterize the underplated material and magmatic processes. Earlier study of ultramafic xenoliths suggested magma underplating and crustal growth in Kuchchh, Gujarat, northwestern Deccan Trap (NWDT). Absence of such xenoliths in Saurashtra peninsula (SP) of NWDT however could not supplement this. Here, we report the mafic/ultramafic xenoliths entrained in high MgO basaltic lava flows of NWDT of SP in Rajkot district of Gujarat, India. The xenoliths are medium to coarse grained, meso - to melanocratic, elongated to angular pyroxenite (Type-I), two pyroxenes gabbro (Type-II) and anorthosite (Type-III) showing sharp contact with host basalt flows. Type-I xenoliths dominated by clinopyroxene (cpx) (Wo49-45 En49-38) with olivine (ol) (Fo84-78), exhibit cumulate texture, Type-II composed of cpx (core-Wo49-48 En42-41), orthopyroxene (opx) (core- En77-76 Fs23-22) and plagioclase (plag) (Ab35-28 An71-64) and Type-III, composed dominantly of plag (Ab67-29 An68-28) with minor opx (En78-76 Fs20-18) and a grain of hercynite (Al2O3=59%) in close association with plag. The basaltic lavas are porphyritic containing ol (Fo88-75), cpx (Wo50-48 En39-37), plag (Ab43-26 An74-54) and opaques. Whole rock geochemical data of xenolith entrained lava flows indicates high MgO (10-11 wt%) with high Ni (421-430 ppm) and Cr (795-1076 ppm). The equilibration temperature calculated from cpx - opx (adjacent grain of cpx and opx, pair-A; inclusion of cpx within opx, pair-B) for Type-II xenolith indicates 778°C and 789°C (pair-A) and 821°C and 832°C (pair-B) at 5 kbar and 10 kbar pressure respectively. Present study suggests that the possibility of magma underplating at crust-mantle interface or presence of layered igneous sill/dyke complex at sub-crustal level. This is corroborated by seismic and other geophysical studies suggesting the magmatic underplating and presence of high velocity layer (Vp 7.1 km/s) with high Poisson's ratio at lower crustal level or crust-mantle interface beneath the NWDT of SP, Gujarat.

Design and rationale of the assessment of proper physiologic response with rate adaptive pacing driven by minute ventilation or accelerometer (APPROPRIATE) trial.

PubMed

Gilliam, F Roosevelt; Giudici, Michael; Benn, Andrew; Koplan, Bruce; Berg, Kellie Jean Chase; Kraus, Stacia Merkel; Stolen, Kira Q; Alvarez, Guy E; Hopper, Donald L; Wilkoff, Bruce L

2011-02-01

Rate-adaptive sensors are designed to restore a physiologic heart rate response to activity, in particular for patients that have chronotropic incompetence (CI). Limited data exist comparing two primary types of sensors; an accelerometer (XL) sensor which detects activity or motion and a minute ventilation (MV) sensor, which detects the product of respiration rate and tidal volume. The APPROPRIATE study will evaluate the MV sensor compared with the XL sensor for superiority in improving functional capacity (peak VO(2)) in pacemaker patients that have CI. This study is a double-blind, randomized, two-arm trial that will enroll approximately 1,000 pacemaker patients. Patients will complete a 6-min walk test at the 2-week visit to screen for potential CI. Those projected to have CI will advance to a 1-month visit. At the 1-month visit, final determination of CI will be done by completing a peak exercise treadmill test while the pacemaker is programmed to DDDR with the device sensors set to passive. Patients failing to meet the study criteria for CI will not continue further in the trial. Patients that demonstrate CI will be randomized to program their rate-adaptive sensors to either MV or XL in a 1:1 ratio. The rate-adaptive sensor will be optimized for each patient using a short walk to determine the appropriate response factor. At a 2-month visit, patients will complete a CPX test with the rate-adaptive sensors in their randomized setting.

Calcium Isotopic Systematics of Peridotite Xenoliths from eastern North China Craton: Implications for Melt-rock Interaction

NASA Astrophysics Data System (ADS)

Zhang, Z.; Zhao, X.; Huang, S.; Xiao, Y.; Li, X.

2017-12-01

In order to better constrain and understand the Ca isotopic variations in the mantle, we report high-precision Ca isotopic data of orthopyroxene (Opx) and clinopyroxene (Cpx) for a set of peridotitic xenoliths from ChangLe, eastern North China craton (NCC). These xenoliths range from lherzolites, Cpx-rich lherzolites to wehrlites, and are variably metasomatised. Lherzolites (Fo≈91) are fertile in mineral composition, and have spoon-shaped to slightly LREE-enriched rare earth element (REE) patterns. They may represent fragments of newly accreted lithospheric mantle that makes up parts of the Late Mesozoic-Cenozoic lithosphere beneath the eastern NCC. Cpx-rich lherzolites and wehrlites formed by reaction of refractory residual peridotites with evolved, Fe-rich silicate melts at high melt/rock ratios, as evidenced by partial to complete replacement of Opx with Cpx, relatively lower Fo contents of Ol (<88) than that from the lherzolites and convex-upward trace element patterns. Our results show that there are large δ44/40Ca variations (1‰) in these peridotitic xenoliths. Lherzolites have δ44/40Ca similar to typical upper mantle value(1.05 ± 0.04). Specifically, lherzolites orthopyroxenes have δ44/40Ca ranging from 1.04 to 1.79, and lherzolites clinopyroxenes have δ44/40Ca from 0.80 to 1.04. In contrast, δ44/40Ca in Cpx-rich lherzolites and wehrlites tend to have lower values reltaive to those of lherzolites. Their clinopyroxenes have δ44/40Ca ranging from 0.42 to 0.92, and their orthopyroxenes have δ44/40Ca ranging from 0.80 to 1.04. Collectively, we identify a positive correlation between clinopyroxene δ44/40Ca and Mg#. Model calculations show that kinetic isotopic fractionation caused by diffusion, probably during mantle melt-rock interaction, is responsible for the positive correlation between clinopyroxene δ44/40Ca and Mg# in these NCC peridotites. Our study shows that melt-rock interaction plays an important role in producing Ca isotopic heterogeneity of the subcontinental mantle.

Experimental study of Fe-Mg- and Ca-distribution between coexisting ortho- and clinopyroxenes at P=294 MPa, T=750 and 800° C

NASA Astrophysics Data System (ADS)

Fonarev, V. I.; Graphchikov, A. A.

1982-07-01

The Fe-Mg-Ca-distribution was investigated in synthesis experiments and with the mineral assemblage orthopyroxene+clinopyroxene+quartz. The phase compositions were identified by X-ray diffraction and, where possible, by electron microprobe. The attainment of equilibrium in the run products was signalled by the compositions from control runs (different solutions) becoming closely similar, by recycling runs, by the attainment of equilibrium from different directions (depending on the composition of starting phases), and by special kinetic experiments. The study produced the following results: (1) the Ca content of the clinopyroxenes decreases with increasing Fe (mol%) from 48.4 at X {Cpx/Fe}=5 to 39.8 at X {Cpx/Fe}=45 (800° C); from 47.6 at X {Cpx/Fe}= 10 to 41.7 at X {Cpx/Fe}=45 (750° C); increasing temperature expands the stability field of the less calcic clinopyroxenes. (2) The Ca content of orthopyroxenes increases slightly with Fe content from 1.8 at X {Opx/Fe}=20.5 to 3.2 at X {Opx/Fe}=75; the temperature effect on the Ca content under the T, P conditions of the experiment was not large. (3) Fe and Mg distribution between the coexisting ortho-and clinopyroxenes is largely temperature-dependent, particularly in the compositional range X {Opx/Fe}=15 75 mol%; as T increases, Fe redistributes from the rhombic to monoclinic mineral. Preliminary estimates of rock formation temperatures using the obtained data show that most of the known two-pyroxene geothermometers overstate the actual values by 50 150° C.

Water in the Oceanic Lithosphere: Salt Lake Crater Xenoliths, Oahu, Hawaii

NASA Technical Reports Server (NTRS)

Peslier, Anne H.; Bizimis, Michael

2010-01-01

Water can be present in nominally anhydrous minerals of peridotites in the form of hydrogen bonded to structural oxygen. Such water in the oceanic upper mantle could have a significant effect on its physical and chemical properties. However, the water content of the MORB source has been inferred indirectly from the compositions of basalts. Direct determinations on abyssal peridotites are scarce because they have been heavily hydrothermally altered. Here we present the first water analyses of minerals from spinel peridotite xenoliths of Salt Lake Crater, Oahu, Hawaii, which are exceptionally fresh. These peridotites are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. A few have unradiogenic Os and radiogenic Hf isotopes and may be fragments of an ancient (2 Ga) depleted and recycled lithosphere. Water contents in olivine (Ol), orthopyroxene (Opx), and clinopyroxene (Cpx) were determined by FTIR spectrometry. Preliminary H_{2}O contents show ranges of 8-10 ppm for Ol, 151-277 ppm for Opx, and 337-603 ppm for Cpx. Reconstructed bulk rock H_{2}O contents range from 88-131 ppm overlapping estimates for the MORB source. Water contents between Ol minerals of the same xenolith are heterogeneous and individual OH infrared bands vary within a mineral with lower 3230 cm^{-1} and higher 3650-3400 cm^{-1} band heights from core to edge. This observation suggests disturbance of the hydrogen in Ol likely occurring during xenolith entrainment to the surface. Pyroxene water contents are higher than most water contents in pyroxenes from continental peridotite xenoliths and higher than those of abyssal peridotites. Cpx water contents decrease with increasing degree of depletion (e.g. increasing Fo in Ol and Cr# in spinel) consistent with an incompatible behavior of water. However Cpx water contents also show a positive correlation with LREE/HREE ratios and LREE concentrations consistent with refertilization. Opx water contents increase with increasing degree of depletion and decrease with LREE/HREE ratios which is inconsistent with the incompatible behavior of H. Calculated water contents of melts in equilibrium with Cpx or Opx range from 1.4 to 3.8 wt % which is higher than that of all Hawaiian lavas. Calculated melts in equilibrium with Cpx and Opx have variable but mostly high H_{2}O/Ce ratios (194 to 1146) consistent with those of rejuvenated stage lavas from Niihau and the South Arch volcanic field, but unlike the drier shield building stage tholeiites. Whether the high water contents recorded in Salt Lake Crater xenoliths were acquired before and/or during interaction of the oceanic lithosphere with the Hawaiian plume will be discussed.

Water in the oceanic lithosphere: Salt Lake Crater xenoliths, Oahu, Hawaii

NASA Astrophysics Data System (ADS)

Peslier, A. H.; Bizimis, M.

2010-12-01

Water can be present in nominally anhydrous minerals of peridotites in the form of hydrogen bonded to structural oxygen. Such water in the oceanic upper mantle could have a significant effect on its physical and chemical properties. However, the water content of the MORB source has been inferred indirectly from the compositions of basalts. Direct determinations on abyssal peridotites are scarce because they have been heavily hydrothermally altered. Here we present the first water analyses of minerals from spinel peridotite xenoliths of Salt Lake Crater, Oahu, Hawaii, which are exceptionally fresh. These peridotites are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. A few have unradiogenic Os and radiogenic Hf isotopes and may be fragments of an ancient ( 2 Ga) depleted and recycled lithosphere. Water contents in olivine (Ol), orthopyroxene (Opx), and clinopyroxene (Cpx) were determined by FTIR spectrometry. Preliminary H_{2}O contents show ranges of 8-10 ppm for Ol, 151-277 ppm for Opx, and 337-603 ppm for Cpx. Reconstructed bulk rock H_{2}O contents range from 88-131 ppm overlapping estimates for the MORB source. Water contents between Ol minerals of the same xenolith are heterogeneous and individual OH infrared bands vary within a mineral with lower 3230 cm^{-1} and higher 3650-3400 cm^{-1} band heights from core to edge. This observation suggests disturbance of the hydrogen in Ol likely occurring during xenolith entrainment to the surface. Pyroxene water contents are higher than most water contents in pyroxenes from continental peridotite xenoliths and higher than those of abyssal peridotites. Cpx water contents decrease with increasing degree of depletion (e.g. increasing Fo in Ol and Cr# in spinel) consistent with an incompatible behavior of water. However Cpx water contents also show a positive correlation with LREE/HREE ratios and LREE concentrations consistent with refertilization. Opx water contents increase with increasing degree of depletion and decrease with LREE/HREE ratios which is inconsistent with the incompatible behavior of H. Calculated water contents of melts in equilibrium with Cpx or Opx range from 1.4 to 3.8 wt % which is higher than that of all Hawaiian lavas. Calculated melts in equilibrium with Cpx and Opx have variable but mostly high H_{2}O/Ce ratios (194 to 1146) consistent with those of rejuvenated stage lavas from Niihau and the South Arch volcanic field, but unlike the drier shield building stage tholeiites. Whether the high water contents recorded in Salt Lake Crater xenoliths were acquired before and/or during interaction of the oceanic lithosphere with the Hawaiian plume will be discussed.

Effect of solar radiation on multidrug resistant E. coli strains and antibiotic mixture photodegradation in wastewater polluted stream.

PubMed

Rizzo, L; Fiorentino, A; Anselmo, A

2012-06-15

The effect of solar radiation on the inactivation of multidrug resistant Escherichia coli (MDR) strains selected from an urban wastewater treatment plant (UWWTP) effluent and the change of their resistance to a mixture of three antibiotics (evaluated in terms of minimum inhibit concentration (MIC)) in wastewater polluted stream were investigated. The solar photodegradation of the mixture of the three target antibiotics (amoxicillin (AMX), ciprofloxacin (CPX), and sulfamethoxazole (SMZ)) was also evaluated. Additionally, since UWWTP effluents are possible sources of antibiotics and antibiotic resistant bacteria, the disinfection by conventional chlorination process of the UWWTP effluent inoculated with MDR strains was investigated too. Solar radiation poorly affected the inactivation of the two selected antibiotic resistant E. coli strains (40 and 60% after 180 min irradiation). Moreover, solar radiation did not affect strain resistance to AMX (MIC>256 μg/mL) and SMZ (MIC>1024 μg/mL), but affected resistance of the lower resistance strain to CPX (MIC decreased by 33% but only after 180 min of irradiation). Chlorination of wastewater sample strongly decreased the number of the two selected antibiotic resistant E. coli strains (99.667 and 99.999%), after 60 min of contact time at 2.0 mg/L initial chlorine concentration, but the resistance of survived colonies to antibiotics was unchanged. Finally, the solar photodegradation rate of the antibiotic mixture (1mg/L initial concentration respectively) resulted in the following order (half-life time): CPX (t(1/2)=24 min)

Deformation, static recrystallization, and reactive melt transport in shallow subcontinental mantle xenoliths (Tok Cenozoic volcanic field, SE Siberia)

NASA Astrophysics Data System (ADS)

Tommasi, Andréa; Vauchez, Alain; Ionov, Dmitri A.

2008-07-01

Partial melting and reactive melt transport may change the composition, microstructures, and physical properties of mantle rocks. Here we explore the relations between deformation and reactive melt transport through detailed microstructural analysis and crystallographic orientation measurements in spinel peridotite xenoliths that sample the shallow lithospheric mantle beneath the southeastern rim of the Siberian craton. These xenoliths have coarse-grained, annealed microstructures and show petrographic and chemical evidence for variable degrees of reaction with silicate melts and fluids, notably Fe-enrichment and crystallization of metasomatic clinopyroxene (cpx). Olivine crystal preferred orientations (CPO) range from strong to weak. [010]-fiber patterns, characterized by a point concentration of [010] normal to the foliation and by dispersion of [100] in the foliation plane with a weak maximum parallel to the lineation, predominate relative to the [100]-fiber patterns usually observed in lithospheric mantle xenoliths and peridotite massifs. Variations in olivine CPO patterns or intensity are not correlated with modal and chemical compositions. This, together with the analysis of microstructures, suggests that reactive melt percolation postdated both deformation and static recrystallization. Preferential crystallization of metasomatic cpx along (010) olivine grain boundaries points to an influence of the preexisting deformation fabrics on melt transport, with higher permeability along the foliation. Similarity between orthopyroxene (opx) and cpx CPO suggests that cpx orientations may be inherited from those of opx during melt-rock reaction. As observed in previous studies, reactive melt transport does not weaken olivine CPO and seismic anisotropy in the upper mantle, except in melt accumulation domains. In contrast, recovery and selective grain growth during static recrystallization may lead to development of [010]-fiber olivine CPO and, if foliations are horizontal, result in apparent isotropy for vertically propagating SKS waves, but strong anisotropy for horizontally propagating surface waves.

Metastable high-pressure transformations of orthoferrosilite Fs82

NASA Astrophysics Data System (ADS)

Dera, Przemyslaw; Finkelstein, Gregory J.; Duffy, Thomas S.; Downs, Robert T.; Meng, Yue; Prakapenka, Vitali; Tkachev, Sergey

2013-08-01

High-pressure single-crystal X-ray diffraction experiments with natural ferrosilite Fs82 (Fe2+0.82Mg0.16Al0.01Ca0.01)(Si0.99Al0.01)O3 orthopyroxene (opx) reveal that at ambient temperature the sample does not transform to the clinopyroxene (cpx) structure, as reported earlier for a synthetic Fs100 end-member (Hugh-Jones et al., 1996), but instead undergoes a series of two polymorphic transitions, first above 10.1(1) GPa, to the monoclinic P21/c phase β-opx (distinctly different from both P21/c and C2/c cpx), also observed in natural enstatite (Zhang et al., 2012), and then, above 12.3(1) GPa to a high-pressure orthorhombic Pbca phase γ-opx, predicted for MgSiO3 by atomistic simulations (Jahn, 2008). The structures of phases α, β and γ have been determined from the single-crystal data at pressures of 2.3(1), 11.1(1), and 14.6(1) GPa, respectively. The two new high-pressure transitions, very similar in their character to the P21/c-C2/c transformation of cpx, make opx approximately as dense as cpx above 12.3(1) GPa and significantly change the elastic anisotropy of the crystal, with the [1 0 0] direction becoming almost twice as stiff as in the ambient α-opx phase. Both transformations involve mainly tetrahedral rotation, are reversible and are not expected to leave microstructural evidence that could be used as a geobarometric proxy. The high Fe2+ content in Fs82 shifts the α-β transition to slightly lower pressure, compared to MgSiO3, and has a very dramatic effect on reducing the (meta) stability range of the β-phase.

Content Analysis of Standardized-Patients' Descriptive Feedback on Student Performance on the CPX.

PubMed

Lee, Young Hee; Lee, Young-Mee; Kim, Byung Soo

2010-12-01

The goal of this study was to explore what kind of additional information is provided by the descriptive comments other than the rating scales, on the physician-patient interaction (PPI) in the clinical performance examination (CPX) and its feedback role in identifying students' strengths and weaknesses in communication skills. The data were collected from 18 medical schools in Seoul and Gyeonggi region, which participated in the CPX for fourth-year medical students in 2006 and 2007. In total 12,650 examination cases in 2006 and 12,814 cases in 2007 were analyzed. Descriptive comments from the standardized patients (SPs) were analyzed by content analysis, which includes a 4-step process: coding, conceptualizing, categorizing and explanation. Ten categories (41 concepts) for 'strength' and 11 for 'weakness' (40 concepts) in the PPI were extracted. Among them, 10 categories were the same in both strength and weakness: providing adequate interview atmosphere, attentive listening, providing emotional support, non-verbal behaviors, professional attitude, questioning, explanation, reaching agreement, counseling & education and conducting adequate physical examination. For the 'structured and organized interview', only weakness was described. In 'providing emotional support' and 'adequate interview atmosphere', comments on strengths were more frequently mentioned than weaknesses. However, communication skills that were related to non-verbal behaviors were more frequently considered weaknesses rather than strengths. The numbers and content of the SP's comments on students' strengths and weaknesses in the PPI varied depending on the case specificities. The results suggest that the SPs' descriptive comments on student' performance on the CPX can provide additional information versus structured quantitative assessment tools such as performance checklists and rating scales. In particular, this information can be used as valuable feedback to identify the advantages and dicadvantages of the PPI and to enhance students' communication skills.

Alkali elemental and potassium isotopic compositions of Semarkona chondrules

USGS Publications Warehouse

Alexander, C.M. O'D.; Grossman, J.N.

2005-01-01

We report measurements of K isotope ratios in 28 Semarkona chondrules with a wide range of petrologic types and bulk compositions as well as the compositions of CPX-mesostasis pairs in 17 type I Semarkona chondrules, including two chondrules with radial alkali zonation and 19 type II chondrules. Despite the wide range in K/Al ratios, no systematic variations in K isotopic compositions were found. Semarkona chondrules do not record a simple history of Rayleigh-type loss of K. Experimentally determined evaporation rates suggest that considerable alkali evaporation would have occurred during chondrule formation. Nevertheless, based on Na CPX-mesostasis distribution coefficients, the alkali contents of the cores of most chondrules in Semarkona were probably established at the time of final crystallization. However, Na CPX-mesostasis distribution coefficients also show that alkali zonation in type I Semarkona chondrules was produced by entry of alkalis after solidification, probably during parent body alteration. This alkali metasomatism may have gone to completion in some chondrules. Our preferred explanation for the lack of systematic isotopic enrichments, even in alkali depleted type I chondrule cores, is that they exchanged with the ambient gas as they cooled. ?? The Meteoritical Society, 2005.

Constraining the Timescales of Rehydration in Nominally Anhydrous Minerals Using 3D Numerical Diffusion Models

NASA Astrophysics Data System (ADS)

Lynn, K. J.; Warren, J. M.

2017-12-01

Nominally anhydrous minerals (NAMs) are important for characterizing deep-Earth water reservoirs, but the water contents of olivine (ol), orthopyroxene (opx), and clinopyroxene (cpx) in peridotites generally do not reflect mantle equilibrium conditions. Ol is typically "dry" and decoupled from H in cpx and opx, which is inconsistent with models of partial melting and/or diffusive loss of H during upwelling beneath mid-ocean ridges. The rehydration of mantle pyroxenes via late-stage re-fertilization has been invoked to explain their relatively high water contents. Here, we use sophisticated 3D diffusion models (after Shea et al., 2015, Am Min) of H in ol, opx, and cpx to investigate the timescales of rehydration across a range of conditions relevant for melt-rock interaction and serpentinization of peridotites. Numerical crystals with 1 mm c-axis lengths and realistic crystal morphologies are modeled using recent H diffusivities that account for compositional variation and diffusion anisotropy. Models were run over timescales of minutes to millions of years and temperatures from 300 to 1200°C. Our 3D models show that, at the high-T end of the range, H concentrations in the cores of NAMs are partially re-equilibrated in as little as a few minutes, and completely re-equilibrated within hours to weeks. At low-T (300°C), serpentinization can induce considerable diffusion in cpx and opx. H contents are 30% re-equilibrated after continuous exposure to hydrothermal fluids for 102 and 105 years, respectively, which is inconsistent with previous interpretations that there is no effect on H in opx under similar conditions. Ol is unaffected after 1 Myr due to the slower diffusivity of the proton-vacancy mechanism at 300°C (2-4 log units lower than for opx). In the middle of the T range (700-1000°C), rehydration of opx and cpx occurs over hours to days, while ol is somewhat slower to respond (days to weeks), potentially allowing the decoupling observed in natural samples to occur via melt re-fertilization. Finally, off-center and oblique sections are common in natural samples and measurements likely reflect at least partially re-equilibrated compositions. Thus, the high water contents in peridotites may reflect variable NAM rehydration over a range of temperatures and timescales relevant for mid ocean ridge processes.

Validation of an incremental field test for the direct assessment of peak oxygen uptake in wheelchair-dependent athletes.

PubMed

Vinet, A; Bernard, P L; Poulain, M; Varray, A; Le Gallais, D; Micallef, J P

1996-05-01

The aim of this study was to validate an incremental field test performed by wheelchair-dependent (WD) athletes. Nine male paraplegic subjects (mean age 28.9 +/- 4.2 years) performed an incremental field test (FT) and a comparable laboratory test (LT) with their own usual wheelchairs. Both tests started with an initial speed of 4 km.hr(-1) and increased by increments of 1 km.hr(-1) every minute until volitional exhaustion. The FT was an adapted Léger and Boucher test (ALBT) and was conducted on a 400 m tartan field marked-off every 50 m with pylons. Ventilatory data were collected every 15 s using a portable telemetric system (Cosmed K2, JFB International, Italy). The LT was performed on an adapted treadmill (Sopur, Germany) and ventilatory data were collected every minute using a breath-by-breath automated system (CPX, Medical Graphics, MN, USA). The LT and the FT were not significantly different for duration (8 min 50 +/- 1 min 24 vs 9 min 55 +/- 29 s), percentage of maximal heart rate (HR, 86.2 +/- 3.9 vs 89.7 +/- 5.3%), maximal minute ventilation (VE, 101.6 +/- 28.5 vs 96.8 +/- 28.2 1.min(-1)) and peak oxygen uptake (VO2 peak, 39.7 + 7.3 vs 36.1 + 5.8 ml.kg(-1).min(-1) assessed with the CPX and the K2, respectively. We concluded that the FT proposed in the present study is a valid test for direct VO2 peak assessment in wheelchair athletes using a portable VO2 telemetric system. Nonetheless, the Léger and Mercier model equation did not accurately predict VO2 max and further investigation is needed to determine a valid VO2 max prediction equation for these subjects during the FT.

High-pressure systematic of NaMe3+Si2O6 pyroxenes: volume compression vs Me3+ cation radius

NASA Astrophysics Data System (ADS)

Periotto, Benedetta; Nestola, Fabrizio; Balic-Zunic, Tonci; Pasqual, Daria; Alvaro, Matteo; Ohashi, Haruo

2010-05-01

Recent investigations have been experimentally demonstrated that Na-clinopyroxenes (Na-cpx) can be stable throughout a wide range of temperatures and pressures in the upper mantle and several works have been carried out in order to better constrain their physical properties. In this work the equation of state of a synthetic NaInSi2O6 clinopyroxene characterized by a trivalent non 3d-transition metal at the Me3+ crystallographic site (space group C2/c) was determined up to about 8 GPa by in situ single-crystal X-ray diffraction. Since previous investigations on CaMe2+Si2O6 showed a different effect when 3d- and non 3d-transition elements located at Me site, the aim of this study is to provide a definitive model capable to predict the high-pressure behaviour of (Ca,Na)(Me2+, Me3+)Si2O6 clinopyroxenes. A single crystal of NaInSi2O6 with size 150*80*50 microns3 was selected for the high-pressure single-crystal X-ray diffraction study. The sample was loaded in an ETH-type diamond anvil cell assembled with a diamond culet of 600 microns in diameter and a gasket preindented to 90 microns with a spark eroded hole of 200 microns in diameter. The cpx was loaded together with a single-crystal of quartz used as an internal pressure standard and some ruby chips used for more approximate determination of the internal pressure. The measurements were performed using a four-circles STOE STADI IV diffractometer on which the software SINGLE08 has been recently installed allowing to perform the eight-position diffracted-beam centering and to fit the diffraction peak profiles. Such centering procedure allows to obtain precise and accurate unit-cell parameters in order to provide values of room pressure bulk modulus affected by a significantly small error. The NaInSi2O6 cpx was investigated at 12 different pressures up to 7.83 GPa. No evidences of phase transformation were found throughout the pressure range investigated. The sample compresses anisotropically with the b direction being strongly the softest one (as expected for cpx) and a and c axes compressing by similar rates. Using a third-order Birch-Murnaghan equation of state (BM3) to fit the pressure - unit-cell volume data we could refine simultaneously the unit-cell volume V0, the room pressure bulk modulus KT0 and its first pressure derivative K'. Using EoSFIT5.2 software we obtained the following coefficients: V0 = 463.42(3) Å3, KT0 = 109.0(6) GPa, K' = 3.3(2). In order to obtain a reliable comparison among NaMe3+Si2O6 pyroxenes, we have plotted the relative compression V/V0 calculated to 10 GPa versus the cation radius of Me3+ site for NaVSi2O6, NaAlSi2O6, NaCrSi2O6, NaFe3+Si2O6 end-members (all C2/c space group). For the NaTiSi2O6 end-member we have performed such calculation using the published P-V data up to 4.34 GPa as at greater pressures this cpx transforms to a triclinic symmetry and cannot be considered for a comparison. According to this comparison, a perfect linear relation is showed for those cpx having a 3d-transition element at Me3+ site, while those cpx with Al and In at Me3+ site totally lie out of trend. In good agreement with a previous work on CaMe2+Si2O6 C2/c compounds (Me2+ = Mg, Fe, Ni), the results of this work confirm that the empirical KT0 * V0 = constant relationship is followed in C2/c cpx only if the same valence electron character is shared and provide a definitive model for (Ca,Na)(Me2+,Me3+)Si2O6 clinopyroxene compounds.

Does medical students’ clinical performance affect their actual performance during medical internship?

PubMed Central

Han, Eui-Ryoung; Chung, Eun-Kyung

2016-01-01

INTRODUCTION This study examines the relationship between the clinical performance of medical students and their performance as doctors during their internships. METHODS This retrospective study involved 63 applicants of a residency programme conducted at Chonnam National University Hospital, South Korea, in November 2012. We compared the performance of the applicants during their internship with their clinical performance during their fourth year of medical school. The performance of the applicants as interns was periodically evaluated by the faculty of each department, while their clinical performance as fourth-year medical students was assessed using the Clinical Performance Examination (CPX) and the Objective Structured Clinical Examination (OSCE). RESULTS The performance of the applicants as interns was positively correlated with their clinical performance as fourth-year medical students, as measured by the CPX and OSCE. The performance of the applicants as interns was moderately correlated with the patient-physician interaction items addressing communication and interpersonal skills in the CPX. CONCLUSION The clinical performance of medical students during their fourth year in medical school was related to their performance as medical interns. Medical students should be trained to develop good clinical skills through actual encounters with patients or simulated encounters using manikins, to enable them to become more competent doctors. PMID:26768172

Does medical students' clinical performance affect their actual performance during medical internship?

PubMed

Han, Eui-Ryoung; Chung, Eun-Kyung

2016-02-01

This study examines the relationship between the clinical performance of medical students and their performance as doctors during their internships. This retrospective study involved 63 applicants to a residency programme conducted at the Chonnam National University Hospital, South Korea, in November 2012. We compared the performance of the applicants during their internship with the clinical performance of the applicants during their fourth year of medical school. The performance of the applicants as interns was periodically evaluated by the faculty of each department, while the clinical performance of the applicants as fourth year medical students was assessed using the Clinical Performance Examination (CPX) and the Objective Structured Clinical Examination (OSCE). The performance of the applicants as interns was positively correlated with their clinical performance as fourth year medical students, as measured by CPX and OSCE. The performance of the applicants as interns was moderately correlated with the patient-physician interactions items addressing communication and interpersonal skills in the CPX. The clinical performance of medical students during their fourth year in medical school was related to their performance as medical interns. Medical students should be trained to develop good clinical skills, through actual encounters with patients or simulated encounters using manikins, so that they are able to become competent doctors. Copyright © Singapore Medical Association.

Heterogeneity of Water Concentrations in the Mantle Lithosphere Beneath Hawaii

NASA Technical Reports Server (NTRS)

Bizimis, M.; Peslier, A. H.; Clague, D.

2017-01-01

The amount and distribution of water in the oceanic mantle lithosphere has implications on its strength and of the role of volatiles during plume/lithosphere interaction. The latter plays a role in the Earth's deep water cycle as water-rich plume lavas could re-enrich an oceanic lithosphere depleted in water at the ridge, and when this heterogeneous lithosphere gets recycled back into the deep mantle. The main host of water in mantle lithologies are nominally anhydrous minerals like olivine, pyroxene and garnet, where hydrogen (H) is incorporated in mineral defects by bonding to structural oxygen. Here, we report water concentrations by Fourier transform infrared spectrometry (FTIR) on olivine, clino- and orthopyroxenes (Cpx & Opx) from spinel peridotites from the Pali vent and garnet pyroxenite xenoliths from Aliamanu vent, both part of the rejuvenated volcanism at Oahu (Hawaii). Pyroxenes from the Aliamanu pyroxenites have high water concentrations, similar to the adjacent Salt Lake Crater (SLC) pyroxenites (Cpx 400-500 ppm H2O, Opx 200 ppm H2O). This confirms that pyroxenite cumulates form water-rich lithologies within the oceanic lithosphere. In contrast, the Pali peridotites have much lower water concentrations than the SLC ones (<25 ppm vs. 50-96 ppm H2O respectively) despite being relatively fertile with >10% modal Cpx and low spinel Cr# (0.09-0.10). The contrast between the two peridotite suites is also evident in their trace elements and radiogenic isotopes. The Pali Cpx are depleted in light REE, consistent with minimal metasomatism. Those of SLC have enriched light REE patterns and Nd and Hf isotopes consistent with metasomatism by alkaline melts. These observations are consistent with heterogeneous water distribution in the oceanic lithosphere that may be related to metasomatism, as well as relatively dry peridotites cross-cut by narrow (?) water-rich melt reaction zones.

Refertilization process in the Patagonian subcontinental lithospheric mantle of Estancia Sol de Mayo (Argentina)

NASA Astrophysics Data System (ADS)

Melchiorre, Massimiliano; Coltorti, Massimo; Gregoire, Michel; Benoit, Mathieu

2015-05-01

Anhydrous mantle xenoliths equilibrated at 1003-1040 °C from Estancia Sol de Mayo (ESM, Central Patagonia, Argentina) and entrained in post-plateau alkaline lavas belonging to Meseta Lago Buenos Aires have been investigated aiming at reconstructing the depletion and enrichment processes that affected this portion of the Patagonia lithospheric mantle. Xenoliths are characterized by a coarse-grained protogranular texture and are devoid of evident modal metasomatism. They show two texturally different clinopyroxenes: protogranular (cpx1) and texturally related to spinel (cpx2). Three different types of orthopyroxenes are also recognized: large protogranular crystals with exsolution lamellae (opx1); small clean and undeformed grains without exsolution lamellae (opx2) and small grains arranged in a vein (opx3). Major element composition of clinopyroxenes and orthopyroxenes highlights two different trends characterized by i) a high Al2O3 content at almost constant mg# and ii) a slight increase in Al2O3 content with decreasing mg#. Clinopyroxenes are enriched in LREE and are characterized by prominent to slightly negative Nb, Zr and Ti anomalies. No geochemical differences are observed between cpx1 and cpx2, while a discrimination can be observed between opx1 and opx2 (LREE-depleted; prominent to slightly negative Ti and Zr anomalies) and opx3 (prominent positive Zr anomaly). Partial melting modeling using both major and trace elements indicates a melting degree between ~ 5% and ~ 13% (up to ~ 23% according to major element modeling) for lherzolites and between ~ 20% and ~ 30% for harzburgites (down to ~ 5% according to trace element modeling). La/Yb and Al2O3, as well as Sr and Al2O3 negative correlations in clinopyroxenes point to a refertilization event affecting this lithospheric mantle. The agent was most probably a transitional alkaline/subalkaline melt, as indicated by the presence of orthopyroxene in the vein and the similar geochemical features of ESM clinopyroxenes and those from Northern Patagonia pyroxenites which are derived from transitional alkaline/subalkaline lavas.

Modulation of Global Transcriptional Regulatory Networks as a Strategy for Increasing Kanamycin Resistance of the Translational Elongation Factor-G Mutants in Escherichia coli

PubMed Central

Mogre, Aalap; Veetil, Reshma T.; Seshasayee, Aswin Sai Narain

2017-01-01

Evolve and resequence experiments have provided us a tool to understand bacterial adaptation to antibiotics. In our previous work, we used short-term evolution to isolate mutants resistant to the ribosome targeting antibiotic kanamycin, and reported that Escherichia coli develops low cost resistance to kanamycin via different point mutations in the translation Elongation Factor-G (EF-G). Furthermore, we had shown that the resistance of EF-G mutants could be increased by second site mutations in the genes rpoD/cpxA/topA/cyaA. Mutations in three of these genes had been discovered in earlier screens for aminoglycoside resistance. In this work, we expand our understanding of these second site mutations, the goal being to understand how these mutations affect the activities of the mutated gene products to confer resistance. We show that the mutation in cpxA most likely results in an active Cpx stress response. Further evolution of an EF-G mutant in a higher concentration of kanamycin than what was used in our previous experiments identified the cpxA locus as a primary target for a significant increase in resistance. The mutation in cyaA results in a loss of catalytic activity and probably results in resistance via altered CRP function. Despite a reduction in cAMP levels, the CyaAN600Y mutant has a transcriptome indicative of increased CRP activity, pointing to an unknown role for CyaA and / or cAMP in gene expression. From the transcriptomes of double and single mutants, we describe the epistasis between the mutation in EF-G and these second site mutations. We show that the large scale transcriptomic changes in the topoisomerase I (FusAA608E-TopAS180L) mutant likely result from increased negative supercoiling in the cell. Finally, genes with known roles in aminoglycoside resistance were present among the misregulated genes in the mutants. PMID:29046437

Water in the Lithospheric Mantle Beneath a Phanerozoic Continental Belt: FTIR Analyses of Alligator Lake Xenoliths (Yukon, Canada)

NASA Technical Reports Server (NTRS)

Gelber, McKensie; Peslier, Ann H.; Brandon, Alan D.

2015-01-01

Water in the mantle influences melting, metasomatism, viscosity and electrical conductivity. The Alligator Lake mantle xenolith suite is one of three bimodal peridotite suites from the northern Canadian Cordillera brought to the surface by alkali basalts, i.e., it consists of chemically distinct lherzolites and harzburgites. The lherzolites have equilibration temperatures about 50 C lower than the harzburgites and are thought to represent the fertile upper mantle of the region. The harzburgites might have come from slightly deeper in the mantle and/or be the result of a melting event above an asthenospheric upwelling detected as a seismic anomaly at 400-500 km depth. Major and trace element data are best interpreted as the lherzolite mantle having simultaneously experienced 20-25% partial melting and a metasomatic event to create the harzburgites. Well-characterized xenoliths are being analyzed for water by FTIR. Harzburgites contain 29-52 ppm H2O in orthopyroxene (opx) and (is) approximately140 ppm H2O in clinopyroxene (cpx). The lherzolites have H2O contents of 27-150 ppm in opx and 46-361 ppm in cpx. Despite correlating with enrichments in LREE, the water contents of the harzburgite pyroxenes are low relative to those of typical peridotite xenoliths, suggesting that the metasomatic agents were water-poor, contrarily to what has been suggested before. The water content of cpx is about double that of opx indicating equilibrium. Olivine water contents are low ((is) less than 5 ppm H2O) and out of equilibrium with those of opx and cpx, which may be due to H loss during xenolith ascent. This is consistent with olivines containing more water in their cores than their rims. Olivines exclusively exhibit water bands in the 3400-3000 cm-1 range, which may be indicative of a reduced environment.

Iridium and Spherules in Late Eocene Impact Deposits

NASA Technical Reports Server (NTRS)

Kyte, F. T.; Liu, S.

2002-01-01

We have been independently examining the Ir (FTK) and spherule (SL) contents of recently discovered late Eocene impact deposits from the south Atlantic and western Indian oceans. These include ODP Sites 1090 [14,15], 709 [lo], and 699 [Liu in prep.]. Iridium abundances at these sites are within the typical range reported for late Eocene deposits, with peak concentrations between 100 and 1000 pg/g. In Table 1 we present estimated net Ir fluences (in ng Ir/cm ) for these and nine other sites. Although there are fewer sites than the K/T boundary, the average of 9 ng Ir/cm2 is probably a good estimate of the late Eocene global flux. This is enough Ir for a 6 km comet (assuming 250 ng/g Ir, p=1.5), is sufficient to produce the Popigai or Chesapeake Bay structures, and is 16% of the flux estimated for the K/T boundary (55 ng/cm2 [ 161). Figure 1 shows the relative abundances of Ir, glassy microtektites and cpx-bearing spherules in sediments from Sites 699 and 1090, which are separated by only 3100 km. Although these two sites have similar Ir anomalies, the abundances of spherules are quite different. Site 1090 has well-defined peaks for both types of spherules, with a peak of 562 cpx spheruledg, while Site 699 contains only a few glassy microtektites and no cpx spherules. While the different abundances of spherules may reflect a heterogeneous distribution of spherules on the Earth s surface, an equally likely cause of this difference may be differential preservation of spherules in the sediment. recovered are only a trace residue of the initial impact deposit. Earlier work found 0.22 ng/g Ir in glassy microtektites from Site 689 [17], an insufficient concentration to support 0.16 ng/g in the bulk sediment at this site. We measured 15 ng/g Ir in a group of 95 cpx spherules from Site 1090 with sizes from 63 to -200 pm, a set typical of the size distribution at this site. Although this is a significant concentration it also cannot support the Ir peak. We presently lack quantitative data on the mass concentration of cpx spherules in Site 1090 sediments, but it is certainly <1 mg/g in The impact record in the late Eocene is very different from that at the Cretaceous-Tertiary In contrast, the late Eocene probably experienced multiple impact events.

Partitioning of copper between olivine, orthopyroxene, clinopyroxene, spinel, garnet and silicate melts at upper mantle conditions

NASA Astrophysics Data System (ADS)

Liu, Xingcheng; Xiong, Xiaolin; Audétat, Andreas; Li, Yuan; Song, Maoshuang; Li, Li; Sun, Weidong; Ding, Xing

2014-01-01

Previously published Cu partition coefficients (DCu) between silicate minerals and melts cover a wide range and have resulted in large uncertainties in model calculations of Cu behavior during mantle melting. In order to obtain true DCumineral/melt values, this study used Pt95Cu05 alloy capsules as the source of Cu to experimentally determine the DCu between olivine (ol), orthopyroxene (opx), clinopyroxene (cpx), spinel (spl), garnet (grt) and hydrous silicate melts at upper mantle conditions. Three synthetic silicate compositions, a Komatiite, a MORB and a Di70An30, were used to produce these minerals and melts. The experiments were conducted in piston cylinder presses at 1.0-3.5 GPa, 1150-1300 °C and oxygen fugacities (fO2) of from ∼2 log units below to ∼5 log units above fayalite-magnetite-quartz (FMQ). The compositions of minerals and quenched melts in the run products were measured with EMP and LA-ICP-MS. Attainment of equilibrium is verified by reproducible DCu values obtained at similar experimental conditions but different durations. The results show that DCu for ol/, opx/, spl/ and possibly cpx/melt increase with increasing fO2 when fO2 > FMQ + 1.2, while DCu for cpx/ and spl/melt also increase with increasing Na2O in cpx and Fe2O3 in spinel, respectively. In the investigated P-T-fO2 conditions, the DCumineral/melt values are 0.04-0.14 for ol, 0.04-0.09 for opx, 0.02-0.23 for cpx, 0.19-0.77 for spl and 0.03-0.05 for grt. These results confirm that Cu is highly incompatible (DCu < ∼0.2) in all the silicate minerals and oxides of the upper mantle with the exception of the high-Fe spinel, in which Cu is moderately incompatible (DCu = 0.4-0.8) and thus Cu will be enriched in the derived melts during mantle partial melting and magmatic differentiation if sulfide is absent. These experimental DCu values are used to assess the controls on Cu behavior during mantle melting. The model results suggest that MORBs and most arc basalts must form by sulfide-present melting at relatively reduced conditions, while high Cu (>70 ppm) arc basalts may form at oxidized, sulfide-absent conditions, which is consistent with the possibility of some high fO2 regions present in the arc mantle.

In-situ fractional crystallization as a major mechanism in differentiation of Karaj sill, northern Iran

NASA Astrophysics Data System (ADS)

Maghdour-Mashhour, Reza; Esmaeily, Dariush

2010-05-01

During the upper Eocene-Oligocene, the Karaj Dam basement sill (KDBS), located within the E-W-trending Alborz range in northern Iran, intruded the middle and upper tuff units of the Karaj Formation. The KDBS consists of a layered series between upper and lower chilled margins, with local fine-grained monzonitic dykes. The rocks of the chilled margins are gabbroic in composition and show porphyritic texture. The rocks show a continuous transition from porphyritic to equigranular texture toward the center of the sill. Most of the KDBS is medium to coarse grained, showing magmatic layering defined by modal variations in pyroxene and plagioclase, the main constituent minerals. The layered series, dominated by gabbro, diorite, and monzodiorite, formed almost upward from the lower to the upper chilled margin, with gradational transitions between rock types. The KDBS shows an S-shaped profile of MgO concentration from the base to the top of the sill. In situ crystallization is indicated by an approximately constant modal abundance of pyroxene and plagioclase, a narrow range of major element contents in the main lithologies (e.g., 49-54 wt% SiO2, 17-19 wt% Al2O3, and 2.7-5.2 wt% MgO), and variable trace element concentrations (e.g., 500-1150 ppm Ba, 45-130 ppm Rb, 150-720ppm Sr, and 50-160 ppm Zr). Disequilibrium crystallization, caused by Soret fractionation in the marginal series, is indicated by an unexpected overall enrichment trend in MgO concentration and Mg# of pyroxenes from the chilled margin (olivine-bearing gabbro) to marginal gabbro. Formation of chilled margins form an effective insulating layer between contacts and overlaying hot, turbulent magma causing magma cool considerably slowly and have sufficient time to produce different differentiated sequence by in-situ nucleation and growth from gabbro to diorite and monzodiorite. Following the formation of chilled margins, the parent magma composition was established on the Plg-Cpx cotectic line of the Ol-Plg-Cpx ternary system or in the Plg field of the Cpx-Ab-An phase system. In the latter system, Plg starts to crystallize in mushy layers and its composition changes from anorthite to albite until reaching the cotectic line, at which point Cpx starts to form. The presence of plagioclase laths as inclusions within large crystals of clinopyroxene indicates cotectic crystallization and the early crystallization of Plg during formation of the gabbroic unit. Subsequently, the liquid line of descent followed the cotectic line toward the Ab-Cpx eutectic point. During this process, gabbroic cumulate formed at the solidified margins of the magma chamber. After the formation of Plg-Cpx cumulate, the evolved interstitial liquid, which had undergone chemical fractionation, migrated out of the gabbroic cumulate pile within the main magma body, thereby changing the composition of the magma reservoir. Consequently, the melt composition would have been different from the initial melt, being more evolved. The subsequent evolution of the liquid line of descent of compositionally new melt followed the same path at every stage of the formation of new melt; the An% of plagioclase decreased and Ab% increased to approximately 40%. In addition, the Cpx content showed a gradual decrease. Eventually, the Plg accumulates as dioritic cumulate in solidified margins of the chamber. Subsequently, the composition of the main magma changed, approaching the eutectic point of the Or-Ab solid solution binary system. in time, at the eutectic point, Kf started to crystallize and formed monzodiorites downward from the roof of the magma chamber during the final stages of differentiation. Although gravitational crystal settling contributed to the evolution of these rocks, it is not considered to have been a major factor in the development of the observed layering.

Nd, Sr and Pb isotopic composition of metasomatised xenoliths from the backarc Patagonian Mantle Wedge: Insights into the origin of the uprising melts

NASA Astrophysics Data System (ADS)

Zanetti, Alberto; Mazzucchelli, Maurizio; Hemond, Christope; Cipriani, Anna; Bertotto, Gustavo W.; Cingolani, Carlos; Vannucci, Riccardo

2010-05-01

Information about the geochemical composition of metasomatic melts migrating through the Patagonian mantle wedge is provided by the ultramafic xenoliths occurrence of Tres Lagos (TL; lat. 49.13°S, long. 71.18°W), Argentina. Such a locality is placed at the eastern border of the Meseta de la Muerte backarc basaltic plateau, where a post-plateau volcanic diatreme contains mantle xenoliths in both pyroclastites and lavas. Its latitude corresponds with the Northern limit of the Austral Volcanic Arc (AVZ), which is separated from the Southern Volcanic Zone (SVZ) by a gap in the arc magmatism ranging between 49° and 46°30' latitude S. The analysed xenoliths have been distinguished into two groups (Group 1 & 2). Group 1 consists of lherzolites and harzburgites, whereas Group 2 is formed by harzburgites. The texture of the Group 1 lherzolites varies from protogranular to granoblastic to porphyroblastic, whereas Group 1 harzburgites have always granoblastic texture. Group 2 harzburgites have granular texture, which may change to porphyroblastic owing to the random concentration of large olivine and orthopyroxene crystals. The clinopyroxenes (Cpx) from Group 1 lherzolites have PM-normalised REE patterns ranging from LREE-depleted (LaN/SmN= 0.24-0.37), to LREE-enriched (LaN/YbN up to 4.08) and spoon-shaped: the latter have minimum at Pr and Pr-Yb concentrations similar to those shown by the LREE-depleted Cpx. The Cpx from Group 1 harzburgites have lower REE concentrations with respect to the lherzolite ones and their REE patterns vary from HREE-enriched, steadily fractionated, (LaN/YbN = 0.21-0.35, Ybn ~ 1-2) to spoon-shaped (LaN/SmN = 2.81; SmN/YbN = 0.89; YbN ~ 3. The Cpx from the Group 2 harzburgites have convex-upward (LaN/SmN = 0.31; SmN/YbN = 1.50) to LREE-enriched (LaN/YbN = 2.94) patterns. The Sr, Nd and Pb isotopic compositions of the Group 1 clinopyroxenes form arrays spanning from DM to the field delimited by the TL basaltic lavas, pointing to EMI end-member. Conversely, Group 2 Cpx have much more radiogenic Sr and less radiogenic Nd values, approaching more closely the EMI and EMII end-members: these features are associated to unradiogenic lead isotopic compositions (206Pb/204Pb = 17.4-18.1; 207Pb/204Pb = 15.55-15.60; 208Pb/204Pb = 37.3-38.5). The combination of petrographic, trace element and isotopic features indicate that TL harzburgites are likely residua after melt-assisted partial melting triggered by melt/fluid migration in the hottest, and perhaps deeper, parts of the pristine DM lithosphere. The interpretation of the Pb, Sr and Nd isotope composition of Group 2 Cpx is not trivial. In analogy with the interpretation proposed for SWIR, it could unravel the occurrence of mantle sources which incorporated ancient crust and failed to homogenise with the DM mantle. Alternatively, it could be the evidence for ancient continental crust of the South America plate dragged down into the mantle by slab motion.

Pyroxene thermometry in the OPX Tongue of the Basement Sill, McMurdo Dry Valleys, Antarctica

NASA Astrophysics Data System (ADS)

Simon, A. C.; Marsh, B.

2005-12-01

Unusually large orthopyroxene (Opx) crystals (5 mm) in the 330 m thick doleritic Basement Sill, the basal sill of the Ferrar Dolerite sill complex, possess strong variations in modal abundance and size both across and along the sill length. Opx phenocrysts (with greatly subordinate cpx) are concentrated toward the middle of the sill, forming an extensive ultramafic tongue, which dominates the thickness of the sill in the feeder zone near Bull Pass and progressively thins with increasing distance in all directions away from the feeder zone. The chilled margins of the sill contain no Opx phenocrysts. Based on the physical position of the Opx tongue and the size, abundance and textural condition of these Opx crystals, it has been postulated that these Opx phenocrysts were entrained in the ascending magma after having been texturally equilibrated at a much deeper location than the present level of sill emplacement, approximately 3- 4 km paleodepth. Determining the ultimate provenance of these phenocrysts is an important step in understanding the formation and overall dynamics of this magmatic system. In a real sense these crystals are important dynamic tracers. To gain insight into the origin and history of transport of these crystals, we performed electron probe microanalyses of pyroxenes from samples collected at 15 m intervals through the entire Basement Sill near the feeder zone in West Bull Pass to quantify the compositions of pyroxenes both within the tongue and the bounding chilled margin in order to use crystal-chemical variations to infer crystal histories. Additionally, we calculated equilibrium temperatures for Opx - Cpx mineral pairs, using the QUILF projection scheme at 200 MPa, to determine if pyroxene crystals in the tongue reflect higher temperatures, indicative of crystallization at deeper levels of the sill-complex plumbing system. Despite some scatter in pyroxene compositions, the data indicate that the En (mole % MgSiO3) component of Opx and Cpx increases systematically with depth through the sill, reaching a plateau in the middle of the transect and then decreasing to the chilled margin at the base of the section. The range of En content of Cpx (27 En) is much less than that of Opx (40 En). The Di component of Cpx acts to some degree as a pivot for the varying En/Fs of Opx. The trend in the En component of Opx parallels roughly the trend in whole-rock MgO, the latter being a manifestation of the increase in abundance of En-rich Opx crystals (phenocrysts) in the central part of the sill. Intra-crystal compositional variation is minimal except for the (expected) decrease in En/Fs of grain margins, reflecting simply the iron enrichment of the residual melt with progressive crystallization. The concentrations of Cr and Al in Opx increase systematically with depth in the sill are highest in Opx of the tongue. Compositional tie-lines for Opx-Cpx pairs from the chilled margin and Opx-tongue, when plotted in the pyroxene quadrilateral, possess negative and positive slopes, respectively. Temperature data define a thermal maximum plateau that coincides with the position of the Opx-tongue; 2-pyroxene temperature increasing on the order of 200 degrees C between the chilled margin (900 to 1000 C)and the Opx-tongue (1070 to 1242 C). The pyroxene tongue represents a subsequent, higher temperature, intrusive event. The relatively high temperatures, trace element abundances, and textural information all suggest that the provenance of the crystals forming the Opx Tongue were entrained from a cumulate pile associated with an earlier magmatic event.

Fluid-induced Crystallization of Majoritic Garnet During Deep Continental Subduction (Western Gneiss Region, Norway)

NASA Astrophysics Data System (ADS)

Scambelluri, M.; Pettke, T.; van Roermund, H. L.

2008-12-01

In ultrahigh pressure (UHP) rocks, garnet containing pyroxene exsolutions derives from breakdown of majorite crystallized at depths > 200 km. Presence of microdiamonds in some of these rocks [1], including those of the Western Gneiss Region (WGR) of Norway [2], may suggest a fluid-bearing environment for the genesis of majorite. The WGR UHP gneisses host garnet peridotite and websterite recording uplift from extraordinary depths prior to uptake in a subducting slab [2]. These ultramafic rocks (islands of Otrøy and Bardane) derive from depleted Archean transition-zone mantle (350 km depth) upwelled and accreted to a cratonic lithosphere (M2 stage). Evidence for this are decimetric garnets (grt) preserved in Otrøy, hosting up to 20 volume% orthopyroxene (opx) and clinopyroxene (cpx) exsolved from precursor majoritic garnet (M1 stage). The pyroxene lamellae (20-30 ¥ìm thick, hundreds of ¥ìm long) [3] were exsolved under high-T, as shown by the garnet/cpx REE distribution [4]. This Archean-mid Proterozoic record is overprinted by the 425- 390 Ma Scandian continental subduction (M3 stage), forming new grt + cpx + opx + phlogopite (phl) + spinel (sp) that contain diamond-bearing micro-inclusions witnessing deep COH subduction fluids [2]. Here we document formation of new majoritic garnet in the M3 assemblage and in veins at Bardane [5]. Textural characteristics, together with the LREE and LILE enrichments of the M3 minerals, indicate that the new majorite is linked to infiltration of subduction fluids during renewed burial towards sub-lithospheric depths. It represents the deepest occurrence of fluid-related microstructures in mantle rocks. The new majoritic garnet crystallized at grain boundaries and in micro-veins at 7 Gpa and 900-1000 °C. It hosts thin pyroxene needles (5 mm thick, 100 mm long) exsolved under comparatively low-T, as indicated by the garnet/cpx REE distribution. The trace element signature of the majorite-bearing subduction assemblage is LREE- (cpx La/Yb = 220) and LILE-enriched (appreciable Li, B, Rb, Ba, Pb, U, Th in cpx and phl), to indicate addition of crustal components. The interstitial and vein M3 majoritic garnet has flat REE patterns (La 1xChondrite; La/Yb= 0.35) and lacks the LREE depletion characteristic of common grt. The px component of majorite thus allows LREE and subordinate LILE storage in this mineral, which becomes a relevant trace element repository in the deep mantle. The REE enriched signature of M3 majorite contrasts the depleted nature of M1 (+ M2) grt: this indicates the presence of two generations of majorite in these rocks and suggests the re-fertilization of initially depleted peridotite by subduction fluid at 200 km depth. Distinct generations of majoritic garnet thus survive in the same terrain, displaying distinct textures, compositions, and exsolution T. The majorite microstructures and compositions enable to discriminate between crystallization environments: hot sub- cratonic lithosphere vs. colder subduction settings. 1 Mposkos ED, Kostopoulos DK, 2001, EPSL 192, 497- 506; 2 Van Roermund HLM. et al., 2002, Geology 30, 959-962; 3 Van Roermund HLM, Drury M., 1998, Terra Nova 10, 295-301; 4 Spengler D. et al., 2006, Nature 440, 913-917; 5 Scambelluri M. et al., 2008, Geology 36, 59-62.

Neoarchean high-pressure metamorphism from the northern margin of the Palghat-Cauvery Suture Zone, southern India: Petrology and zircon SHRIMP geochronology

NASA Astrophysics Data System (ADS)

Saitoh, Yohsuke; Tsunogae, Toshiaki; Santosh, M.; Chetty, T. R. K.; Horie, Kenji

2011-08-01

We report the metamorphic pressure-temperature ( P- T) history of mafic granulites from two localities in southern India, one from Kanja Malai in the northern margin and the other from Perundurai in the central domain of the Palghat-Cauvery Suture Zone (PCSZ). The PCSZ is described in recent models as the trace of the suture along which crustal blocks were amalgamated within the Gondwana supercontinent during Late Neoproterozoic-Cambrian. The mafic granulite from Kanja Malai yields P- T conditions of 750-800 °C and 8-12 kbar reflecting the partially retrograded conditions following a peak high-pressure (HP) metamorphic event. The common Grt + Cpx + Qtz assemblage in these rocks and lack of decompression texture suggest that peak metamorphism was probably buffered by Grt + Cpx + Opx + Pl + Qtz assemblage, following which the rocks were exhumed through a gradual P- T decrease. The mafic granulite from Perundurai (Grt + Cpx + Pl) contains Opx + Pl symplectite commonly occurring between garnet and clinopyroxene, suggesting the progress of reaction: Grt + Cpx + Qtz → Opx + Pl, with the Grt + Cpx + Qtz representing the peak metamorphic assemblage. The reaction microstructures and calculated P- T conditions suggest that the mafic granulites from Perundurai underwent peak HP metamorphism at P > 12 kbar and T = 800-900 °C and subsequent isothermal decompression along a clockwise P- T path, in contrast to the P- T path inferred for Kanja Malai. The contrasting P- T paths obtained from the two localities suggest that whereas Perundurai is a part of the metamorphic orogen developed within the PCSZ during Gondwana assembly, the high-pressure granulites of Kanja Malai belong to a different orogenic regime. In order to evaluate this aspect further, we analyzed zircons in a charnockite and garnet-bearing quartzo-feldspathic gneiss associated with the HP granulites from Kanja Malai which yielded mean 207Pb/ 206Pb magmatic protolith emplacement ages of 2536.1 ± 1.4 Ma and 2532.4 ± 3.7 Ma, and peak metamorphic ages of 2477.6 ± 1.8 Ma and 2483.9 ± 2.5 Ma, respectively. These results closely compare with the available magmatic (2530-2540 Ma) and metamorphic (2470-2480 Ma) ages reported from charnockites in the Salem Block at the southern fringe of the Archean Dharwar craton, immediately north of the PCSZ. The Neoarchean/Paleoproterozoic ages obtained from Kanja Malai correlate with the tectonic history at the margin of the Archean craton. Although no age data are available for the Perundurai mafic granulite, the close correspondence of their P- T data and exhumation path with those reported for Late Neoproterozoic-Cambrian HP-UHT metamorphism within the PCSZ suggest that these rocks form part of the Gondwana-forming orogen.

Geochemistry of oceanic igneous rocks - Ridges, islands, and arcs - With emphasis on manganese, scandium, and vanadium

USGS Publications Warehouse

Doe, B.R.

1997-01-01

A database on a number of elements in oceanic volcanic rocks is presented, including the principal major-element oxides - SiO2, TiO2, Al2O3, Fe2O3(T), MnO, MgO, CaO, Na2O, K2O, and P2O5 (where T refers to total iron) - and the trace elements - Ba, Ce, Cr, Cu, Ni, Sc, Sr, V, Pb (mainly by isotope dilution), Yb, Zn, and Zr. Interpretations are given for transition metals, with emphasis on Mn, Sc, and V, in order to determine the concentration of the elements in primitive melts and assess their trends in magmatic differentiation. Transition metals are not enriched in plagioclase, so all are incompatible with pure plagioclase removal - that is, they become enriched in the melt. Both Cr and Ni are known to be highly compatible with olivine separation - i.e., they are depleted in the melt early in differentiation. Also, Sc is compatible with clinopyroxene (Cpx) removal from the melt and is depleted by separation of Cpx. Copper does not fit well in any of the principal silicates, but Cu, like Ni, is greatly enriched in sulfides that may remain in the source or separate from the magma. Decreasing Ni abundances and increasing Cu contents during differentiation are a sign of olivine separation. In the analysis presented herein, V - in the absence of Cpx separation - is found to behave remarkably like the moderately incompatible element Zn, and these two elements add to the list of element pairs of similar incompatibility whose ratios are insensitive to differentiation and to submarine weathering as well. Both are enhanced in titanomagnetite, so both would he compatible during titanomagnetite separation. When Cpx separates, however, V becomes compatible like Sc, but Zn remains incompatible. Thus, decreasing V (and Sc) contents and increasing Zn contents during differentiation are a sign of Cpx separation. Manganese often behaves much like Zn and therefore is moderately incompatible, but Mn is less compatible than Zn and V in titanomagnetite. Thus, decreasing Zn and V with increasing Mn is an indication of titanomagnetite removal. Dual compatible and incompatible trends with differentiation are found chiefly for Cu, Sc, and Sr. Distinguishing mid-ocean ridge basalts (MORB), oceanic-island volcanic rocks (OIV), and island-arc volcanic rocks (IAV) may be accomplished by plots of Ce/Yb versus Ba/Ce, where OIV plot to higher values of Ce/Yb than do MORB, and IAV data plot to higher values of Ba/Ce than do those of MORB. These ratios do not seem to be significantly affected by submarine weathering.

Petrology and geochemistry of the Tasse mantle xenoliths of the Canadian Cordillera: A record of Archean to Quaternary mantle growth, metasomatism, removal, and melting

NASA Astrophysics Data System (ADS)

Polat, Ali; Frei, Robert; Longstaffe, Fred J.; Thorkelson, Derek J.; Friedman, Eyal

2018-07-01

Mantle xenoliths hosted by the Quaternary Tasse alkaline basalts in the Canadian Cordillera, southeastern British Columbia, are mostly spinel lherzolite originating from subcontinental lithospheric mantle. The xenoliths contain abundant feldspar veins, melt pockets and spongy clinopyroxene, recording extensive alkaline metasomatism and partial melting. Feldspar occurs as veins and interstitial crystal in melt pockets. Melt pockets occur mainly at triple junctions, along grain boundaries, and consist mainly of olivine, cpx, opx and spinel surrounded by interstitial feldspar. The Nd, Sr and Pb isotopic compositions of the xenoliths indicate that their sources are characterized by variable mixtures of depleted MORB mantle and EM1 and EM2 mantle components. Large variations in εNd values (-8.2 to +9.6) and Nd depleted mantle model ages (TDM = 66 to 3380 Ma) are consistent with multiple sources and melt extraction events, and long-term (>3300 Ma) isolation of some source regions from the convecting mantle. Samples with Archean and Paleoproterozoic Nd model ages are interpreted as either have been derived from relict Laurentian mantle pieces beneath the Cordillera or have been eroded from the root of the Laurentian craton to the east and transported to the base of the Cordilleran lithosphere by edge-driven convection currents. The oxygen isotope compositions of the xenoliths (average δ18O = +5.1 ± 0.5‰) are similar to those of depleted mantle. The average δ18O values of olivine (+5.0 ± 0.2‰), opx (+5.9 ± 0.6‰), cpx (+6.0 ± 0.6‰) and spinel (+4.5 ± 0.2‰) are similar to mantle values. Large fractionations for olivine-opx, olivine-cpx and opx-cpx pairs, however, reflect disequilibrium stemming from metasomatism and partial melting. Whole-rock trace element, Nd, Sr, Pb and O isotope compositions of the xenoliths and host alkaline basalts indicate different mantle sources for these two suites of rocks. The xenoliths were derived from shallow lithospheric sources, whereas the alkaline basalts originated from a deeper asthenospheric mantle source.

Lake Ellen kimberlite, Michigan, U.S.A.

USGS Publications Warehouse

McGee, E.S.; Hearn, B.C.

1983-01-01

The recently discovered Lake Ellen kimberlite, in northern Michigan, indicates that bedrock sources of diamonds found in glacial deposits in the Great Lakes area could lie within the northern U.S. Magnetic surveys show a main kimberlite 200 m in diameter and an adjacent body 25 x 90 m(?). The kimberlite cuts Proterozoic volcanic rocks that overlie Archean basement, but is post-Ordovician in age based on abundant Ordovician(?) dolomite inclusions. Xenocrysts and megacrysts are ilmenite (abundant, 12.5-19% MgO), pyropealmandine and Cr-pyrope (up to 9.3% Cr2O3), Cr-diopside (up to 4.5% Cr2O3), olivine (Fo 91), enstatite and phlogopite. The kimberlite contains fragments of crustal schist and granulite, as well as disaggregated crystals and rare xenoliths of eclogites, garnet pyroxenites and garnet peridotites from a heterogeneous upper mantle. Eclogites, up to 3 cm size, show granoblastic equant or tabular textures and consist of jadeitic cpx (up to 8.4% Na20, 15.3% Al2O3), pyrope-almandine, ? rutile ? kyanite ? sanidine ? sulfide. Garnet pyroxenite contains pyrope--(0.44% Cr2O3) + cpx (0.85% Na2O, 0.53% Cr2O3) + Mg-Al spinel. Mineral compositions of rare composite xenocrysts of garnet + cpx are distinctively peridotitic, pyroxenitic or eclogitic. Calculated temperatures of equilibration are 920-1060 ?C for the eclogites and 820-910?C for the garnet pyroxenite using the Ellis-Green method. Five peridotite garnet-clinopyroxene composite xenocrysts have calculated temperatures of 980-1120?C using the Lindsley-Dixon 20 kb solvus. Spinel pyroxenite and clinopyroxene-orthopyroxene composites have lower calculated temperatures of 735?C and 820-900?C, respectively. Kyanite-bearing eclogites must have formed at pressures greater than 18-20 kb. Using the present shield geotherm with a heat flow value of 44mW/m 2 for the time of kimberlite emplacement, the eclogite temperatures imply pressures of 35-48 kb (105-140 km) and the garnet pyroxenite temperatures indicate pressures of 24-29 kb (75-90 km). Temperatures of two peridotitic garnet-cpx composite xenocrysts if on a shield geotherm, imply pressures within the diamond stability field.

Chemistry of amphiboles and clinopyroxenes from Euganean (NE Italy) cumulitic enclaves: implications for the genesis of melts in an extensional setting

NASA Astrophysics Data System (ADS)

Bartoli, O.; Meli, S.; Sassi, R.; Magaraci, D.

2009-04-01

The magmatism of the Euganean Volcanic District (Veneto Volcanic Province, VVP) developed in the last phases of the Alpine orogenesis; the geochemical and geophysical data are consistent with an extensional geodynamic context (Milani et al., 1999). Cumulitic gabbroic enclaves occur within the Euganean trachytes, and Bartoli et al. (2008) pointed to their cogenetic origin with the Euganean host lavas. Sr isotopic data suggest that these cumulates derived from uncontaminated mantle-derived liquids. We analysed both cumulus and intercumulus amphiboles and clinopyroxenes by electron microprobe and LA-ICP-MS. The cumulus-intercumulus Cpx are diopsides and augites. The Mg#Cpx varies in a wide range (Mg#cumulus-Cpx= 0.74-0.84 and Mg#intercumulus-Cpx= 0.67-0.68). They show a MREE enrichment relative to LREE and HREE (LaN/SmN= 0.46-0.68 and TbN/YbN= 2.18-4.77). No significant Eu anomaly (Eu/Eu* = 0.78-1.23) was observed. On a chondrite-normalized spiderdiagram Cpx exhibits significant Pb and Co negative anomalies, and less evident negative anomalies for Sr and Zr. La, Sm and HREE increase, whereas Ba, Ti, Li and V decrease from core to rim. These Cpx exhibit high Cr contents (701-2958 ppm). Moreover, they display trace element differences when compared to Cpx from MORB gabbros. We analyzed also amphiboles: pargasites, edenites and kaersutites. In the cumulus Amph Mg# varies in the range 0.60-0.69, whereas in the intercumulus assemblage from 0.57 to 0.63. The high K2O and TiO2 contents are distinct from that of amphiboles in MORB gabbros. LREE are enriched relative to HREE (LaN/YbN = 5.07-7.56). Moreover, TbN/YbN = 2.50-4.02 indicates a HREE depletion relative to MREE. REE patterns lack a significant Eu anomaly (Eu/Eu* = 1.06-1.19). From core to rim Th and U decrease in cumulus crystals, but they increase in the intercumulus Amph. Ba (258-282 ppm) is enriched relative to other LILE and Nb-Ta are enriched relative to LREE. Cr varies in the range 423-594 ppm. The similar REE and HFSE content of intercumulus and cumulus Amph may suggest the existence of some post-cumulus processes. We calculated the chemistry of the liquids which should have been in equilibrium with cumulus phases, employing a set of Ds•l. In the liquid in equilibrium with Cpx LREE and MREE are enriched up to 40 and 11 times respectively relative to HREE, which are at about N-MORB concentrations (LaN/YbN = 42.5 and SmN/YbN = 11). Some LILE (i.e., Rb and Ba), Th and U are enriched relative to HFSE and REE. The theoretical composition of the liquid in equilibrium with Amph differs from Cpx-liquid in the marked enrichment of U and Th over LILE and HFSE. A LREE and MREE enrichment is observed (LaN/YbN = 35.4 and SmN/YbN = 3.6). The discrepancies of calculated liquid compositions cannot be ascribed only to the uncertainty in the choice of Ds•l. This may indicate trace element modifications in response to post-cumulus processes involving the amphiboles. The concentrations of HFSE in the calculated liquids (Zr/Hf = 60.2-72.7, Zr/Nb = 1.7-6.5 and Th/Hf = 3.8-6.9) and the incompatible element ratios, (e.g., La/Nb = 0.5-0.7, Pb/Ce = 0.01-0.05, La/Y = 2.3-2.8 and Ce/Nd = 1.9-2.8), are not comparable to those of N-MORB but to those of HIMU-OIB suggesting that typical MORB-type mantle couldn't be the source of these liquids. Nb and Ta are variable, possibly due to an heterogeneity in the lithospheric mantle. The existence of some peculiar trace element signatures of the recalculated liquids (LILE enrichment, high LREE/HREE ratio and abrupt enrichment in U and Th) has been attributed to slab-derived melts/fluids with an abundant sedimentary component. Our estimates are in agreement with the geodynamic scenario proposed by Macera et al. (2007), who explained the occurrence of both HIMU-OIB-type magmatism and subduction-related metasomatism in the VVP mantle lithosphere. According to their model, a mantle plume with HIMU-OIB geochemical signature rose from the deep mantle twice with subsequent partial melting episodes of the plume material: the first time during Paleocene, before the subducted European lithospheric slab (from which the LILE-, U- and Th-enriched fluids/melts derived) intercepted the mantle plume, and the second time during middle Eocene, after slab detachment and opening of a plate window. The liquids we have modeled can derive from partial melting of a subcontinental mantle source percolated by HIMU-OIB- and subduction-related fluids/melts with an abundant sedimentary component. Similarly, our recalculated liquids display some trace element signatures close to those shown by the liquids computed by Tiepolo & Tribuzio (2005) for cumulates of the Adamello batholith during alpine orogeny.

X-linked CHARGE-like Abruzzo-Erickson syndrome and classic cleft palate with ankyloglossia result from TBX22 splicing mutations.

PubMed

Pauws, E; Peskett, E; Boissin, C; Hoshino, A; Mengrelis, K; Carta, E; Abruzzo, M A; Lees, M; Moore, G E; Erickson, R P; Stanier, P

2013-04-01

X-linked cleft palate (CPX) is caused by mutations in the gene encoding the TBX22 transcription factor and is known to exhibit phenotypic variability, usually involving either a complete, partial or submucous cleft palate, with or without ankyloglossia. This study hypothesized a possible involvement of TBX22 in a family with X-linked, CHARGE-like Abruzzo-Erickson syndrome, of unknown etiology. The phenotype extends to additional features including sensorineural deafness and coloboma, which are suggested by the Tbx22 developmental expression pattern but not previously associated in CPX patients. A novel TBX22 splice acceptor mutation (c.593-5T>A) was identified that tracked with the phenotype in this family. A novel splice donor variant (c.767+5G>A) and a known canonical splice donor mutation (c.767+1G>A) affecting the same exon were identified in patients with classic CPX phenotypes and were comparatively analyzed using both in silico and in vitro splicing studies. All three variants were predicted to abolish normal mRNA splicing and an in vitro assay indicated that use of alternative splice sites was a likely outcome. Collectively, the data showed the functional effect of several novel intronic splice site variants but most importantly confirms that TBX22 is the gene underlying Abruzzo-Erickson syndrome, expanding the phenotypic spectrum of TBX22 mutations. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Partial assimilation during crystallization of a (gabbroic) pluton: the gabbronoritic zone of the Atlantis core complex

NASA Astrophysics Data System (ADS)

Barbieri, E.; Brunelli, D.; Hellebrand, E.; Johnson, K. T.; Paganelli, E.

2011-12-01

The lower oceanic crust largely consists of cumulates, representing crystallization products from melt that erupt on the ocean floor. Removal of interstitial melt from the cumulate minerals is believed to be efficient, driven by compaction. Reaction between percolating melts and cumulate minerals can result in micron-to-meter-scale variations in the phase assemblage and composition. Here we report on the results of a highly detailed petrological study of a sequence of lower crustal gabbroic rocks, using textural and chemical criteria to reconstruct the complex interplay between reactive melts and a highly crystallized gabbroic mush. The exceptionally well-preserved gabbroic sequence was recovered during IODP Legs 304 and 305 at the Atlantis Massif. These gabbros are characterized by high-frequency magmatic refilling of a mush zone, as attested by the cm-m thick succession of magmatic layers, with sharp to diffuse contact. The main gabbroic body (between 300 and 1100 mbsf ) is bounded by two layers of olivine rich troctolites interpreted as pervasively fluxed mantle rocks. Closely spaced sampling of the intervals 930-980 and 1130-1190 mbsf reveal evolved gabbroic lithologies closely interspersed with more primitive members. Olivine and plagioclase consumption is accompanied by progressive crystallization of clinopyroxene (cpx) and later orthopyroxene (opx). Both initially appear as interstitial grains, followed by poikilitic and granophyric textures. The onset of reactive percolation is often associated with deformation, recorded as kink bands in relict olivine and plagioclase and wavy mineral contacts wet by thin cpx layers. As a result, plagioclase and olivine chadacrysts in cpx and opx have resorbed appearance (rounded deformed chadacrysts in large undeformed oikocrysts). Typical chemical signatures of this incomplete resorption are high Ni in pyroxene-hosted low-Fo olivines. Resorbed plagioclases have higher REE and positive Sr correlation with Ba attesting to a progressive equilibration with evolved melts. Simple fractional accumulation in a closed system is unable to fit the observed cpx and opx trends. Large deviations from linear correlations require an influx of primitive material in an ongoing differentiating system. Based on the observed consumption of the primitive assemblage we calculate high rates of assimilation of primitive cumulates. However, the assimilation ratio estimated from cpx trace element contents is much higher than that required to fit the opx trends. These observations attest for a multistage evolution of the sampled rocks: the process starts as near-fractional crystallization, reaching high degrees of crystallinity before melt percolation induces olivine and plagioclase resorption, increasing porosity and crystallizing clinopyroxene. The subsequent crystallization of opx is characterized by a decrease of the assimilation rate and porosity reduction.As such reactive signatures have been reported from other oceanic gabbros, AFC processes in the lower oceanic crust are possibly widespread and may strongly contribute to the compositional systematic observed in global MORB.

Calc-Alkaline Liquid Lines of Descent Produced Under Oxidizing Conditions: An Experimental and Petrologic Study of Basaltic Tephras from the Western Aleutians, AK

NASA Astrophysics Data System (ADS)

Waters, L. E.; Cottrell, E.; Kelley, K. A.; Coombs, M. L.

2017-12-01

Buldir, a volcano in the western Aleutian Arc, features eruptive products that form one of the most strongly calc-alkaline compositional trends observed in modern island arcs. Previous studies of Buldir and nearby submarine dredge samples suggest that Buldir's mineral phases and isotopic signatures may be introduced through mixing of two distinct magmas and/or melts, as no experimental study has been able to create a liquid line of descent (LLD) as calc-alkaline as Buldir's whole rock trend. To further test this hypothesis, we present new experimental results and petrographic analysis of tephras from the 2015 field season of the GeoPRISMS shared platform. Tephras (51.4-54.8 wt% SiO2) have a phenocryst assemblage of olivine + plagioclase + cpx + spinel ± hornblende (hbl). In natural samples, plagioclase comprises most of the crystal volume, followed by either olivine or hornblende. In samples that contain abundant hbl (Hbl Mg#=65-80), olivine and plagioclase span a range of compositions from Fo72-86 and An60-93, respectively. In samples without hbl, olivines are more forsteritic (Fo79-90), and plagioclase is less calcic (An65-83). Spinel is ubiquitous; with Cr- rich spinel inclusions in olivine and hbl, and magnetite in the groundmass. Our petrologic observations do not require magma mixing. To determine whether these observations could be consistent with the LLD of a single parental liquid, we conducted a series of phase equilibrium experiments at 100 MPa in a rapid-quench cold-seal (MHC) apparatus on the most primitive natural lava from Buldir (9.34 wt% MgO). Experiments were equilibrated in noble metal capsules pre-saturated with Fe, and buffered at Re-ReO2 under water-saturated conditions. Spinel [(Mg80, Fe2+20)(Fe3+52, Cr83, Al66)O4] is the liquidus phase, followed by olivine, then plagioclase, then cpx, and lastly, hbl. Once cpx and hbl saturate, spinel composition shifts to magnetite. Experimental run products demonstrate that all mineral phases observed in the tephras are plausible phenocrysts. Experimental glass compositions demonstrate that the strongly calc-alkaline trend observed at Buldir can be produced through crystallization of a parental liquid under water-saturated conditions at relatively high oxygen fugacity, where the effect of high fO2 is to stabilize spinel as a liquidus phase.

Interplay between HIV-1 and Host Genetic Variation: A Snapshot into Its Impact on AIDS and Therapy Response

PubMed Central

Sampathkumar, Raghavan; Shadabi, Elnaz; Luo, Ma

2012-01-01

As of February 2012, 50 circulating recombinant forms (CRFs) have been reported for HIV-1 while one CRF for HIV-2. Also according to HIV sequence compendium 2011, the HIV sequence database is replete with 414,398 sequences. The fact that there are CRFs, which are an amalgamation of sequences derived from six or more subtypes (CRF27_cpx (cpx refers to complex) is a mosaic with sequences from 6 different subtypes besides an unclassified fragment), serves as a testimony to the continual divergent evolution of the virus with its approximate 1% per year rate of evolution, and this phenomena per se poses tremendous challenge for vaccine development against HIV/AIDS, a devastating disease that has killed 1.8 million patients in 2010. Here, we explore the interaction between HIV-1 and host genetic variation in the context of HIV/AIDS and antiretroviral therapy response. PMID:22666249

Antimicrobial gelatin-based elastomer nanocomposite membrane loaded with ciprofloxacin and polymyxin B sulfate in halloysite nanotubes for wound dressing.

PubMed

Shi, Rui; Niu, Yuzhao; Gong, Min; Ye, Jingjing; Tian, Wei; Zhang, Liqun

2018-06-01

Bacterial infection is a major problem world-wide, especially in wound treatment where it can severely prolong the healing process. In this study, a double drug co-delivery elastic antibacterial nanocomposite was developed by combining ciprofloxacin (CPX) and polymyxin B sulfate-loaded halloysite clay nanotubes (HNTs-B) into a gelatin elastomer. CPX nanoparticles which act against both gram positive and gram-negative bacterium were dispersed directly in the matrix, and polymyxin B sulfate was loaded in HNTs and then distributed into the matrix. The effect of CPX and HNTs-B content on the physical properties, cytotoxicity, fibroblast adhesion and proliferation, in vitro drug release behavior and anti-bacterial properties were systematically investigated. The ciprofloxacin crystals and HNT-B were distributed in the matrix uniformly. The HNTs in the drug loading system not only enhanced the matrix' tensile strength but also slowed down the release rate of the high dissoluble polymyxin B sulfate. When the amount of HNT in the matrix increased, the thermal stability and tensile strength also increased but the polymyxin B sulfate release rate decreased because the HNTs prevented the drug release inside. All the nanocomposites exhibited antimicrobial activity against both gram-negative and gram-positive bacteria with the dual combination of drugs released from the nanocomposites. Furthermore, this kind of gelatin-based nanocomposites possesses higher water-absorbing quality, low cytotoxicity, adaptable biodegradability and good elasticity which can satisfy the requirements for an ideal biomaterial for use in wound healing applications. Copyright © 2018. Published by Elsevier B.V.

Constraining late stage melt-peridotite interaction in the lithospheric mantle of southern Ethiopia: evidence from lithium elemental and isotopic compositions

NASA Astrophysics Data System (ADS)

Alemayehu, Melesse; Zhang, Hong-Fu; Seitz, Hans-Michael

2017-10-01

Lithium (Li) elemental and isotopic compositions for mineral separates of coexisting olivine, orthopyroxene and clinopyroxene of mantle xenoliths from the Quaternary volcanic rocks of southern Ethiopian rift (Dillo and Megado) reveal the influence of late stage melt-peridotite interaction on the early depleted and variably metasomatized lithospheric mantle. Two types of lherzolites are reported (LREE-depleted La/Sm(N) = 0.11-0.37 × Cl and LREE-enriched, La/Sm(N) = 1.88-15.72 × Cl). The depleted lherzolites have variable range in Li concentration (olivine: 2.1-5.4 ppm; opx: 1.1-2.3 ppm; cpx: 1.0-1.8 ppm) and in Li isotopic composition (δ7Li in olivine: -9.4 to 1.5‰; in opx: -4.5 to 3.6‰; in cpx: -17.0 to 4.8‰), indicating strong disequilibrium in Li partitioning and Li isotope fractionation between samples. The enriched lherzolites have limited range in both Li abundances (olivine: 2.7-3.0 ppm; opx: 1.1-3.1 ppm; cpx: 1.1-2.3 ppm) and Li isotopic compositions (δ7Li in olivine: -1.3 to +1.3‰; in opx: -2.0 to +5.0‰; in cpx: -7.5 to +4.8‰), suggest that the earlier metasomatic event which lead to LREE enrichment could also homogenize the Li contents and its isotopes. The enriched harzburgite and clinopyroxenite minerals show limited variation in Li abundances and variable Li isotopic compositions. The Li enrichments of olivine and clinopyroxene correlate neither with the incompatible trace element enrichment nor with the Sr-Nd isotopic compositions of clinopyroxene. These observations indicate that the metasomatic events which are responsible for the LREE enrichment and for the Li addition are distinct, whereby the LREE-enrichment pre-dates the influx of Li. The presence of large Li isotopic disequilibria within and between minerals of depleted and enriched peridotites suggest that the lithospheric mantle beneath the southern Ethiopian rift has experienced recent melt-peridotite interaction. Thus, the Li data set reported in this study offer new additional evidence for the existence of late stage metasomatism, which probably occurred at shallow depth briefly before and/or during entrainment and ascent of mantle xenoliths to the surface.

Textural changes of FER-A peridotite in time series piston-cylinder experiments at 1.0 GPa, 1300°C

NASA Astrophysics Data System (ADS)

Schwab, B. E.; Mercer, C. N.; Johnston, A.

2012-12-01

A series of eight 1.0 GPa, 1300°C partial melting experiments were performed using FER-A peridotite starting material to investigate potential textural changes in the residual crystalline phases over time. Powdered peridotite with a layer of vitreous carbon spheres as a melt sink were sealed in graphite-lined Pt capsules and run in CaF2 furnace assemblies in 1.27cm piston-cylinder apparatus at the University of Oregon. Run durations ranged from 4 to 128 hours. Experimental charges were mounted in epoxy, cut, and polished for analysis. In a first attempt to quantify the mineral textures, individual 500x BSE images were collected from selected, representative locations on each of the experimental charges using the FEI Quanta 250 ESEM at Humboldt State University. Noran System Seven (NSS) EDS system was used to collect x-ray maps (spectral images) to aid in identification of phases. A combination of image analysis techniques within NSS and ImageJ software are being used to process the images and quantify the mineral textures observed. The goals are to quantify the size, shape, and abundance of residual olivine (ol), orthopyroxene (opx), clinopyroxene (cpx), and spinel crystals within the selected sample areas of the run products. Additional work will be done to compare the results of the selected areas with larger (lower magnification) images acquired using the same techniques. Preliminary results indicate that measurements of average grain area, minimum grain area, and average, maximum, and minimum grain perimeter show the greatest change (generally decreasing) in measurements for ol, opx, and cpx between the shortest-duration, 4-hour, experiment and the subsequent, 8-hour, experiment. The largest relative change in nearly all of these measurements appears to be for cpx. After the initial decrease, preliminary measurements remain relatively constant for ol, opx, and cpx, respectively, in experiments from 8 to 128 hours in duration. In contrast, measured parameters of spinel grains increase from the 4-hour to 8-hour experiment and continue to fluctuate over the time interval investigated. Spinel also represents the smallest number of individual grains (average n = 25) in any experiment. Average aspect ratios for all minerals remain relatively constant (~1.5-2) throughout the time series. Additional measurements and refinements are underway.

First-principles investigations of equilibrium Ca, Mg, Si and O isotope fractionations between silicate melts and minerals

NASA Astrophysics Data System (ADS)

Qi, Y.; Liu, X.; Kang, J.; He, L.

2017-12-01

Equilibrium isotope fractionation factors are essential for using stable isotope data to study many geosciences processes such as planetary differentiation and mantle evolution. The mass-dependent equilibrium isotope fractionation is primarily controlled by the difference in bond energies triggered by the isotope substitution. With the recent advances in computational capabilities, first-principles calculation has become a reliable tool to investigate equilibrium isotopic fractionations, greatly improving our understanding of the factors controlling isotope fractionations. It is important to understand the isotope fractionation between melts and minerals because magmatism is critical for creating and shaping the Earth. However, because isotope fractionation between melts and minerals is small at high temperature, it is difficult to experimentally calibrate such small signature. Due to the disordered and dynamic character of melts, calculations of equilibrium isotope fractionation of melts are more challenging than that for gaseous molecules or minerals. Here, we apply first-principles molecular dynamics method to calculate equilibrium Ca, Mg, Si, and O isotope fractionations between silicate melts and minerals. Our results show that equilibrium Mg, Si, and O isotope fractionations between olivine and pure Mg2SiO4 melt are close to zero at high temperature (e.g. δ26Mgmelt-ol = 0.03 ± 0.04‰, δ30Simelt-ol = -0.06 ± 0.07‰, δ18Omelt-ol = 0.07‰ ± 0.08 at 1500 K). Equilibrium Ca, Mg, Si, and O isotope fractionations between diopside and basalt melt (67% CaMgSi2O6 + 33% CaAl2Si2O8) are also negligible at high temperature (e.g. δ44/40Camelt-cpx = -0.01 ± 0.02‰, δ26Mgmelt-cpx = -0.05 ± 0.14‰, δ30Simelt-cpx = 0.04 ± 0.04‰, δ18Omelt-cpx = 0.03 ± 0.07‰ at 1500 K). These results are consistent with the observations in natural samples that there is no significant Ca, Mg, Si, and O isotope fractionation during mantle partial melting, demonstrating the reliability of our methods. Thus, our results can be used to understand stable isotope fractionation during partial melting of mantle peridotite or fractional crystallization during magmatic differentiation. The first-principles molecular dynamics method is a promising tool to obtain equilibrium fractionation of more isotope systems for complicate liquids.

Constraining magma ascent and degassing paths with olivine- and clinopyroxene-hosted melt inclusions: Evidence for multiple depths of crystallization and boundary-layer entrapment

NASA Astrophysics Data System (ADS)

Lloyd, A. S.; Newcombe, M. E.; Plank, T. A.

2016-12-01

Although olivine-hosted melt inclusions (MIs) remain the gold standard for recovering volatile concentrations of primitive magmas, later-fractionating minerals may be more appropriate for assessing magma storage conditions immediately prior to eruption. We present volatile analyses of MIs entrapped in early (Mg# 81-83) olivine and later (Mg# 70-80) clinopyroxene (Cpx) from the 1977 eruption of Seguam volcano, to assess the ascent history prior to this violent strombolian eruption. The olivine-hosted MIs contain average volatile concentrations (n=16) of 3.79 wt% H2O, 167 ppm CO2, 592 ppm Cl, and 133 ppm F, consistent with an entrapment pressure of 200 to 300 MPa ( 10-13 km depth) if the CO2 contained in the bubble is taken into account (Moore et al., 2015). Cpx phenocrysts contain two distinct MI assemblages; the inner assemblage consists of randomly distributed, rounded MIs which never contain a vapor bubble. Average volatile concentrations of the inner assemblage MIs (n=11) are 0.96 wt% H2O, 98 ppm CO2, 798 ppm Cl, and 280 ppm F, consistent with an entrapment at much shallower depth, 2 km. The outer assemblage contains inclusions too small for routine volatile analysis. Inner assemblage Cpx-hosted MIs preserve average enrichments of 1.3x and 2x for Cl and F respectively, and are similarly enriched in incompatible minor and trace elements (up to a factor of 5x). Two potential scenarios can explain these observations. The enrichments may represent the entrapment of an unrelated highly-fractionated, shallow magma (which is unsupported by the whole rock record at Seguam). A second possibility is enrichment through boundary layer entrapment during a period of rapid crystal growth during ascent through the upper crust. Boundary layer entrapment during MI formation is further supported by a negative correlation between the degree of enrichment and the diffusivity of individual elements, which is consistent with growth rates 10-8 m/s. Although the olivine-hosted MIs record a volatile-rich storage region, the later-fractionating Cpx indicate a phase of rapid crystallization, likely driven by water loss from the melt at shallow depths. This work highlights the information added by analyzing multiple phases in order to reconstruct the degassing path of magma prior to eruption.

Petrology and metamorphic evolution of ultramafic rocks and dolerite dykes of the Betic Ophiolitic Association (Mulhacén Complex, SE Spain): evidence of eo-Alpine subduction following an ocean-floor metasomatic process

NASA Astrophysics Data System (ADS)

Puga, E.; Nieto, J. M.; Díaz de Federico, A.; Bodinier, J. L.; Morten, L.

1999-10-01

The Betic Ophiolitic Association, cropping out within the Mulhacén Complex (Betic Cordilleras), is made up of numerous metre- to kilometre-sized lenses of mafic and/or ultramafic and meta-sedimentary rocks. Pre-Alpine oceanic metasomatism and metamorphism caused the first stage of serpentinization in the ultramafic sequence of this association, which is characterized by local clinopyroxene (Cpx) breakdown and Ca-depletion, and complementary rodingitization of the basic dykes intruded in them. Subsequent eo-Alpine orogenic metamorphism developed eclogite facies assemblages in ultramafic and basic lithotypes, which were partly retrograded in Ab-Ep-amphibolite facies conditions during a meso-Alpine event. The heterogeneous development of the oceanic metasomatism in the ultramafic rock-types led to the patchy development of highly serpentinized Ca-depleted domains, without gradual transition to the host, and less serpentinized, Cpx-bearing ultramafites, mainly lherzolitic in composition. The high-pressure eo-Alpine recrystallization of these ultramafites in subduction conditions originated secondary harzburgites in the Ca-depleted domains, consisting of a spinifex-like textured olivine+orthopyroxene paragenesis, and a diopside+Ti-clinohumite paragenesis in the enclosing lherzolitic rocks. During the meso-Alpine event, secondary harzburgites were partly transformed into talc+antigorite serpentinites, whereas the diopside and clinohumite-bearing residual meta-lherzolites were mainly transformed into Cpx-bearing serpentinites. Relics of mantle-derived colourless olivine may be present in the more or less serpentinized secondary harzburgites. These relics are overgrown by the eo-Alpine brown pseudo-spinifex olivine, which contains submicroscopic inclusions of chromite, ilmenite and occasional halite and sylvite, inherited from its parental oceanic serpentine. The same type of mantle-derived olivine relics is also preserved within the Cpx-bearing serpentinites, although it has been partly replaced by the eo-Alpine Ti-clinohumite. The dolerite dykes included in the ultramafites were partly rodingitized in an oceanic environment. They were then transformed during the eo-Alpine event into meta-rodingites in their border zones and into eclogites towards the innermost, less-rodingitized portions. Estimated P- T conditions for the high-pressure assemblages in ultramafic and basic lithotypes range from 650 to 750°C and 16-25 kb.

Pyroxenite and peridotite xenoliths from Hexigten, Inner Mongolia: Insights into the Paleo-Asian Ocean subduction-related melt/fluid-peridotite interaction

NASA Astrophysics Data System (ADS)

Zou, Dongya; Liu, Yongsheng; Hu, Zhaochu; Gao, Shan; Zong, Keqing; Xu, Rong; Deng, Lixu; He, Detao; Gao, Changgui

2014-09-01

The in situ major, trace-element and Sr-isotopic compositions of the peridotite and pyroxenite xenoliths from the Hexigten region in the Xing-Meng orogenic belt (XMOB) were examined to evaluate the influences and contributions of the Paleo-Asian Oceanic slab subduction on the lithospheric mantle transformation. Pyroxenes in the Type 1 pyroxenite exhibit low and variable Mg# (67-85) and relatively high 87Sr/86Sr ratios (0.7036-0.7053), indicating that they were formed by assimilation and fractional crystallization processes during a basaltic underplating event. The peridotite and Type 2 pyroxenite xenoliths sampled the lithospheric mantle and recorded subduction-related metasomatism. The mineral chemistries of the Type 1 peridotite suggest that the lithospheric mantle beneath this area suffered 1-15% melt extraction. Clinopyroxene (Cpx) in some Type 1 peridotites are characterized by high (La/Yb)N coupled with marked depletions in high field strength elements (HFSE) (Nb, Ta, Zr, Hf and Ti) and negative correlations between the low Ti/Eu (Nb/La) and 87Sr/86Sr ratios (0.7037-0.7055), suggesting metasomatism by subduction-related CO2-rich fluids. Olivine (Ol) and orthopyroxene (Opx) in the Type 2 peridotite are characterized by a relatively low Mg# but high Ni contents. In addition to the normal incompatible element-depleted Opx, Opx with enrichments in Rb, Ba, Th, U, Nb, Ta and LREE were observed, as well. The Mg# of incompatible element-depleted Opx exhibits weak zonations (i.e., decreasing from the cores to the rims). Cpx and Opx of the Type 2 pyroxenite exhibit similarly high Mg# and Ni contents. Rb, Ba, Th, U, Nb, Ta and LREE contents and 87Sr/86Sr ratios of the Cpx increase from the cores to the rims. Moreover, Opx in the Type 2 peridotite and Cpx in the Type 2 pyroxenite exhibit increased Nb/Ta ratios and Ni contents relative to those in the Type 1 peridotites. These observations collectively suggest a rutile-bearing eclogite-derived silicic melt-peridotite reaction as the origin for the Type 2 peridotite and pyroxenite. Considering the geological setting, it is suggested that the melt/fluid-peridotite interactions were caused by the Paleo-Asian Ocean subduction, which could have contributed significantly to the transformation of the lithospheric mantle beneath the northern margin of the NCC, as well.

Proterozoic Eastern Sayan ophiolites (Central Asian Orogenic Belt) record subduction initiation in vicinity of continental block

NASA Astrophysics Data System (ADS)

Belyaev, Vasilii; Gornova, Marina; Medvedev, Alexander; Dril, Sergey; Karimov, Anas

2017-04-01

Geochemical study of cumulate and volcanic rocks from ˜ 1020 Ma Eastern Sayan ophiolites1 (Siberia, Russia) is used to provide a correlation between two ophiolitic belts and link them to subduction initiation setting. Studied areas include Ospin and Ilchir massifs to the East and Dunzhugur to the West of Early Precambrian Gargan block. Ophiolitic cumulates represent peridotite-pyroxenite-gabbro-norite suite with crystallization orders of Cr-Sp - Ol - Cpx - Opx - Plag, and Cr-Sp - Ol - Opx - Amph - (Cpx) - Plag. Clinopyroxene is augite-diopside with Mg# 85-95, low Al2O3 (1-2.5%) and TiO2 (0.05-0.2%). Amph is Mg-hornblende to edenite (Mg# 84-86, 5-8% Al2O3, 0.3-0.6% TiO2). Cr-Sp has Cr# 65-83 and 0.05-0.3% TiO2 in cumulates with high Opx proportion, while in Cpx-dominating pyroxenites chemistry of Cr-Sp is variable (Cr# 40-75, 0.05-0.5% TiO2). Due to alteration, Ol and Opx chemistry is available only for some samples (Ol: Mg# 88, 0.2-0.3% NiO; Opx: Mg# 89, 1.6% Al2O3). Whole-rock MgO ranges 9 to 38%. Amph-free pyroxenites and gabbro-norites show flat to slightly depleted REE pattern with negative HFSE anomalies. Amph-pyroxenites have fractionated trace-element pattern with LREE enrichment, Nb-Ti minima at slightly higher HFSE abundances. In-situ LA-ICP-MS analysis of Cpx in Amph-free pyroxenites and gabbro-norites revealed moderately depleted to flat REE and Nb-Zr-Hf-Ti depletion, with low trace element abundances (La/SmPM = 0.14-0.9, Zr 0.6-2.3, Nd = 0.2-1.1, Yb = 0.2-0.7 ppm). Melts calculated to be in equilibrium with Cpx using distribution coefficients2 are REE-flat to slightly LREE-enriched (La/SmPM = 1-4) at low HREE abundances (0.5-1.5 ppm Yb). Overall, crystallization orders, mineral and whole-rock chemistry suggest origin of ophiolitic cumulates from low-Ca boninites or primitive andesites (higher Opx or Amph proportion) to high-Ca boninites or primitive island arc tholeiites (Cpx-dominating, Amph-free associations with subordinate Opx). Ophiolitic volcanics and dikes are low-Ca and intermediate-Ca boninites, andesite-basalts, andesites, dacites of calc-alkaline (CA) affinity with rare evolved island-arc tholeiitic (IAT) andesite-basalts. They resemble appropriate rocks of intraoceanic island arcs, forearcs, and ophiolites. Boninites and CA-andesites are LREE-enriched (La/SmPM 1.2-3.8) at low HREE (0.5-1.6 ppm Yb) contents while evolved IAT show flat REE (La/SmPM = 1.1) and higher abundances (2.4-2.8 ppm Yb), and both have negative Nb anomalies. Nd-isotopic data expressed as epsilon Nd(1020Ma) values are -2.3 to +4.1 in cumulates, -2.8 to +0.4 in boninites and andesites, and +2.3 to +2.7 in IAT (compared to epsilon Nd(1020Ma) +7.8 in depleted mantle). The ophiolites obducted on the Gargan continental block, which contains Archean gneisses with epsilon Nd(1020) = -20 to -281. Subduction and recycling of sediments derived from these gneisses could explain enriched Nd isotopic characteristics of the studied ophiolitic rocks. The boninite-andesite-IAT association is usually found in subduction initiation settings recorded by modern forearc regions and forearc ophiolites. The difference of the Eastern Sayan ophiolites is their supposed formation close to ancient continental block which supplied recycled material into newly formed subduction zone. 1. Sklyarov et al (2016) Russ Geol Geophys 57, 127-140 2. Sobolev et al (1996) Petrology 3, 326-336.

Inclusion/lamella mineralogy and chemical characteristics of garnets from the Garnet Ridge in the Colorado Plateau, northern Arizona

NASA Astrophysics Data System (ADS)

Sato, Y.; Ogasawara, Y.

2013-12-01

A wide variety of garnets as xenocrysts and those in xenoliths, come from kimberlitic diatreme (Smith et al. 2004), occurs at the Garnet Ridge. Koga and Ogasawara (2012) classified these garnets into 9 groups: (a) Cr and pyrope-rich garnet, (b) pyrope-rich reddish brown garnet, (c) reddish brown garnet, (d) garnet in eclogite, (e) garnet in metasomatized eclogite, (f) garnet aggregate, (g) garnet megacryst, (h) garnet in metasomatic rock I, (i) garnet in metasomatic rock II. They divided genetically these groups into four: mantle peridotite (a, b), subducted oceanic crust (d, e), high-pressure metasomatism (c, f, g), low-pressure metasomatism (h, i).In this study, the following 4 groups (a, b, f, g) were chose for inclusion mineralogy by laser Raman spectroscopy. Groups (a) and (b): pyrope-rich garnets (a: 45-82, b: 61-80 Prp mol%) both Cr-rich and Cr-poor (a: 1.0-5.9, b: 0.0-1.0 wt.% Cr2O3) are Ca-poor (1.5-7.0 wt.% CaO) and single-crystals of 5-15 mm in diameter. Group (a) is identical to chrome-pyrope based on the classification of kimberlitic garnets by Dawson and Stephens (1975). CaO-Cr2O3 ratio of (a, b) indicates lherzorite origin (Turkin and Sobolev 2009). Wang et al. (1999) have reported the detailed inclusion and lamella mineralogy of pyrope-rich garnets from the Garnet Ridge. We identified inclusions of Chl (OH: 3450, 3582, 3679 cm-1), Amp (OH: 3685, 3711 cm-1), Ol, Opx, Cpx, Rt (OH: 3295 cm-1), Mgs, Dol, Cal, sulfides, fluid (OH: 3445 cm-1) and spherical composite inclusions of Amp, Ap, Dol, Mgs, Rt and sulfides, and oriented lamellae (presumable exsolution) of Qz, Ol, Opx, Cpx, Amp, Chl, Rt, Ilm, crichtonite (6-7 Peaks at 120-820 cm-1), carmichaelite (710-782 cm-1, OH: 3340 cm-1), Ap (OH: 3570 cm-1) and Ti-Chn (OH: 3404, 3527, 3564 cm-1) adjacent to the oriented Ol. The mineral assemblages of the inclusion and lamella show a correlation with the host garnet compositions; inclusions: (a, b) Ol + Opx + Cpx × composite, (b, low Mg) Opx + Cpx + Amp, oriented lamellae: (a) Rt + Cr-bearing titanates + Ol, (b) Rt + titanates + Px or Ol, (b, low Mg) Rt + Ilm + Amp + Chl. Groups (f) and (g): aggregate (f) and megacryst (g) are rich in Alm, Grs and Pyp; almost 1:1:1. The chemistries of the garnets fall into pyrope-grossular almandine by Dawson and Stephens (1975). Both garnets contain Cpx, Zrn, sulfides, and oriented Ap and Rt rods. Chl, Cpx, Rt and Ilm grains occur near grain boundaries of (f). A significant variation of hydroxyls was detected in the garnets from the Garnet Ridge (Ogasawara et al. 2012); hydroxyls in garnets (c, f, g) and (a, b), but no hydroxyls in garnet (d).Detected hydroxyls in the host garnet and in identified inclusion/lamella and their assemblages may lead to clarify the volatile environments of the metasomatic processes in peridotites and subducted materials underneath the Colorado Plateau. References Turkin, A.I., Sobolev, N.V. (2009) Russ. J. Geol. Geophys., 50, 1169-1182. Smith, D. et al. (2004) Geochem. Geophys. Geosyst., 5, 4. Dawson, J. B., Stephens, W. E. (1975) J. Geol., 83, 589-607. Koga, I., Ogasawara, Y. (2012) AGU Fall Meeting, V43A-2824. Wang, L. et al., (1999) Contrib. Mineral. Petrol., 135, 164-178. Ogasawara, Y., Sakamaki, K. and Koga, I. (2012) AGU Fall Meeting, V43A-2821.

Two viral strains and a possible novel recombinant are responsible for the explosive injecting drug use-associated HIV type 1 epidemic in Estonia.

PubMed

Zetterberg, Veera; Ustina, Valentina; Liitsola, Kirsi; Zilmer, Kai; Kalikova, Nelli; Sevastianova, Ksenia; Brummer-Korvenkontio, Henrikki; Leinikki, Pauli; Salminen, Mika O

2004-11-01

HIV-1 infection has been rare in Estonia. In 2000, an explosive epidemic among injecting drug users was detected in the Eastern border region, resulting in 3603 newly reported cases by the end of 2003. The molecular epidemiology of the outbreak was studied to establish whether the Estonian epidemic is linked to the epidemics in Eastern Europe. Over 200 newly infected individuals were prospectively sampled from June 2000 to March 2002 in a geographically representative way, with known dates of diagnosis and information of probable route of transmission. Viral regions coding for two viral gene regions were directly sequenced from plasma viral RNA and phylogenetically analyzed. In addition, a larger region coding for the entire env gene was sequenced from one sample and studied for indications of possible recombinant structure. The Estonian HIV outbreak was found to be caused by simultaneous introduction of two strains: a minor subtype A strain very similar to the Eastern European subtype A strain (approximately 8% of cases), and a second major strain (77%) found to be most closely related to the CRF06-cpx strain, previously described only from African countries. The variability in the two clusters was very low, suggesting point source introductions. Ten percent of cases seemed to be newly generated recombinants of the A and CRF06-cpx strains. Analysis of viral diversification over time revealed a rate of change within the V3 region of 0.83%/year for the CRF06-cpx strain, consistent with findings from other subtypes. Due to the relatively frequently found novel recombinant forms, the Estonian HIV-1 epidemic may allow studies of coinfection and intersubtype recombination in detail.

[Equating scores using bridging stations on the clinical performance examination].

PubMed

Yoo, Dong-Mi; Han, Jae-Jin

2013-06-01

This study examined the use of the Tucker linear equating method in producing an individual student's score in 3 groups with bridging stations over 3 consecutive days of the clinical performance examination (CPX) and compared the differences in scoring patterns by bridging number. Data were drawn from 88 examinees from 3 different CPX groups-DAY1, DAY2, and DAY3-each of which comprised of 6 stations. Each group had 3 common stations, and each group had 2 or 3 stations that differed from other groups. DAY1 and DAY3 were equated to DAY2. Equated mean scores and standard deviations were compared with the originals. DAY1 and DAY3 were equated again, and the differences in scores (equated score-raw score) were compared between the 3 sets of equated scores. By equating to DAY2, DAY1 decreased in mean score from 58.188 to 56.549 and in standard deviation from 4.991 to 5.046, and DAY3 fell in mean score from 58.351 to 58.057 and in standard deviation from 5.546 to 5.856, which demonstrates that the scores of examinees in DAY1 and DAY2 were accentuated after use of the equation. The patterns in score differences between the equated sets to DAY1, DAY2, and DAY3 yielded information on the soundness of the equating results from individual and overall comparisons. To generate equated scores between 3 groups on 3 consecutive days of the CPX, we applied the Tucker linear equating method. We also present a method of equating reciprocal days to the anchoring day as much as bridging stations.

Modulation of Pancreatic Islets' Function and Survival During Aging Involves the Differential Regulation of Endoplasmic Reticulum Stress by p21 and CHOP

PubMed Central

Mihailidou, Chrysovalantou; Chatzistamou, Ioulia; Papavassiliou, Athanasios G.

2017-01-01

Abstract Aims: Although endoplasmic reticulum (ER) stress is recognized as a major mechanism causing pancreatic dysfunction in diabetes, little is known on how aging modulates the process. Here, we compared the response with ER stress, viability, and insulin release from pancreatic islets of young (6 weeks) or aged (14 months) mice. Results: Islets from aged mice were more sensitive to ER stress than their younger counterparts; they exhibited more pronounced unfolded protein response (UPR) and caspase activation and displayed compromised insulin release after high-glucose stimulation. Genetic ablation of p21 sensitized the islets to ER stress, especially in the aged group, whereas CHOP ablation was protective for islets from both aged and younger animals. Ciclopirox (CPX), an iron chelator that stimulates p21 expression, protected islets from glucotoxicity and mice from diet-induced diabetes, especially in the aged group in a manner that was both p21 and CHOP dependent. Innovation: For the first time, the study shows that age-dependent susceptibility to diet-induced diabetes is associated with the activity of p21 and CHOP in pancreatic islets and that CPX protects islets from glucotoxicity and mice from diabetes in an age-dependent manner. Conclusions: Our results identify ER stress as an age-dependent modifier of islet survival and function by mechanisms implicating enhancement of CHOP activity and inhibition of the protective activity of p21. These findings suggest that interventions restoring the homeostatic activity of ER stress, by agents such as CPX, may be particularly beneficial for the management of diabetes in the elderly. Antioxid. Redox Signal. 27, 185–200. PMID:27931122

CRF19_cpx is an Evolutionary fit HIV-1 Variant Strongly Associated With Rapid Progression to AIDS in Cuba

PubMed Central

Kouri, Vivian; Khouri, Ricardo; Alemán‬, Yoan; Abrahantes, Yeissel; Vercauteren, Jurgen; Pineda-Peña, Andrea-Clemencia; Theys, Kristof; Megens, Sarah; Moutschen, Michel; Pfeifer, Nico; Van Weyenbergh, Johan; Pérez, Ana B.; Pérez, Jorge; Pérez, Lissette; Van Laethem, Kristel; Vandamme, Anne-Mieke

2015-01-01

Background Clinicians reported an increasing trend of rapid progression (RP) (AIDS within 3 years of infection) in Cuba. Methods Recently infected patients were prospectively sampled, 52 RP at AIDS diagnosis (AIDS-RP) and 21 without AIDS in the same time frame (non-AIDS). 22 patients were sampled at AIDS diagnosis (chronic-AIDS) retrospectively assessed as > 3 years infected. Clinical, demographic, virological, epidemiological and immunological data were collected. Pol and env sequences were used for subtyping, transmission cluster analysis, and prediction of resistance, co-receptor use and evolutionary fitness. Host, immunological and viral predictors of RP were explored through data mining. Findings Subtyping revealed 26 subtype B strains, 6 C, 6 CRF18_cpx, 9 CRF19_cpx, 29 BG-recombinants and other subtypes/URFs. All patients infected with CRF19 belonged to the AIDS-RP group. Data mining identified CRF19, oral candidiasis and RANTES levels as the strongest predictors of AIDS-RP. CRF19 was more frequently predicted to use the CXCR4 co-receptor, had higher fitness scores in the protease region, and patients had higher viral load at diagnosis. Interpretation CRF19 is a recombinant of subtype D (C-part of Gag, PR, RT and nef), subtype A (N-part of Gag, Integrase, Env) and subtype G (Vif, Vpr, Vpu and C-part of Env). Since subtypes D and A have been associated with respectively faster and slower disease progression, our findings might indicate a fit PR driving high viral load, which in combination with co-infections may boost RANTES levels and thus CXCR4 use, potentially explaining the fast progression. We propose that CRF19 is evolutionary very fit and causing rapid progression to AIDS in many newly infected patients in Cuba. PMID:26137563

CRF19_cpx is an Evolutionary fit HIV-1 Variant Strongly Associated With Rapid Progression to AIDS in Cuba.

PubMed

Kouri, Vivian; Khouri, Ricardo; Alemán, Yoan; Abrahantes, Yeissel; Vercauteren, Jurgen; Pineda-Peña, Andrea-Clemencia; Theys, Kristof; Megens, Sarah; Moutschen, Michel; Pfeifer, Nico; Van Weyenbergh, Johan; Pérez, Ana B; Pérez, Jorge; Pérez, Lissette; Van Laethem, Kristel; Vandamme, Anne-Mieke

2015-03-01

Clinicians reported an increasing trend of rapid progression (RP) (AIDS within 3 years of infection) in Cuba. Recently infected patients were prospectively sampled, 52 RP at AIDS diagnosis (AIDS-RP) and 21 without AIDS in the same time frame (non-AIDS). 22 patients were sampled at AIDS diagnosis (chronic-AIDS) retrospectively assessed as > 3 years infected. Clinical, demographic, virological, epidemiological and immunological data were collected. Pol and env sequences were used for subtyping, transmission cluster analysis, and prediction of resistance, co-receptor use and evolutionary fitness. Host, immunological and viral predictors of RP were explored through data mining. Subtyping revealed 26 subtype B strains, 6 C, 6 CRF18_cpx, 9 CRF19_cpx, 29 BG-recombinants and other subtypes/URFs. All patients infected with CRF19 belonged to the AIDS-RP group. Data mining identified CRF19, oral candidiasis and RANTES levels as the strongest predictors of AIDS-RP. CRF19 was more frequently predicted to use the CXCR4 co-receptor, had higher fitness scores in the protease region, and patients had higher viral load at diagnosis. CRF19 is a recombinant of subtype D (C-part of Gag, PR, RT and nef), subtype A (N-part of Gag, Integrase, Env) and subtype G (Vif, Vpr, Vpu and C-part of Env). Since subtypes D and A have been associated with respectively faster and slower disease progression, our findings might indicate a fit PR driving high viral load, which in combination with co-infections may boost RANTES levels and thus CXCR4 use, potentially explaining the fast progression. We propose that CRF19 is evolutionary very fit and causing rapid progression to AIDS in many newly infected patients in Cuba.

Phylodynamics of the HIV-1 epidemic in Cuba.

PubMed

Delatorre, Edson; Bello, Gonzalo

2013-01-01

Previous studies have shown that the HIV-1 epidemic in Cuba displayed a complex molecular epidemiologic profile with circulation of several subtypes and circulating recombinant forms (CRF); but the evolutionary and population history of those viral variants remains unknown. HIV-1 pol sequences of the most prevalent Cuban lineages (subtypes B, C and G, CRF18_cpx, CRF19_cpx, and CRFs20/23/24_BG) isolated between 1999 and 2011 were analyzed. Maximum-likelihood analyses revealed multiple introductions of subtype B (n≥66), subtype C (n≥10), subtype G (n≥8) and CRF18_cpx (n≥2) viruses in Cuba. The bulk of HIV-1 infections in this country, however, was caused by dissemination of a few founder strains probably introduced from North America/Europe (clades B(CU-I) and B(CU-II)), east Africa (clade C(CU-I)) and central Africa (clades G(CU), CRF18(CU) and CRF19(CU)), or locally generated (clades CRFs20/23/24_BG). Bayesian-coalescent analyses show that the major HIV-1 founder strains were introduced into Cuba during 1985-1995; whereas the CRFs_BG strains emerged in the second half of the 1990s. Most HIV-1 Cuban clades appear to have experienced an initial period of fast exponential spread during the 1990s and early 2000s, followed by a more recent decline in growth rate. The median initial growth rate of HIV-1 Cuban clades ranged from 0.4 year⁻¹ to 1.6 year⁻¹. Thus, the HIV-1 epidemic in Cuba has been a result of the successful introduction of a few viral strains that began to circulate at a rather late time of the AIDS pandemic, but then were rapidly disseminated through local transmission networks.

Raman and IR Spectroscopic Study of Hydrous Pyroxenes

NASA Astrophysics Data System (ADS)

Kung, J.; Li, C.; Stalder, R.; Inoue, T.; Chuang, S.; Balfan-Casanova, N.; Skogby, H.

2017-12-01

Pyroxene group is one of major composed minerals at upper mantle and is nominally anhydrous mineral (NAM), in terms of its crystal chemistry. The analysis of field specimens showed the mantle-derived pyroxene phase containing some amount of hydrogen within crystal structure, the major incorporation mechanism to be as hydroxyl, OH¯, which chemical component treats as `water', H2O. Compared with the other mantle-derived olivine and garnet, the crystal chemistry of pyroxene phases (opx and cpx) is more complex that can result in different OH¯ bonding environments that would greatly affect the geophysics-interested physical properties, for example, elasticity and transport properties. In order to understand how the hydroxyl bonding condition with different composition of opx and cpx in this study, IR and Raman spectroscopies were employed to investigate the lattice modes and hydroxyl-bonding environments with different composition and crystal structures. The studied pyroxene specimens included natural hydrous pyroxenes and synthesized hydrous orthoenstatite (OEN) at high pressure and temperature (4-7 GPa, 1300-1400°C). The measured IR band range was carried out from 2800 to 3600 cm-1 and the Raman range from 50 to 3600 cm-1. The analysis showed that the band of 3600 cm-1 is the major feature in natural opx specimens but its intensity would be varied in different crystal orientation. For synthesized OEN, the number of observed IR band is higher than that reported in previous studies. The common major bands observed in natural cpx are around 3500 cm-1. The Raman measurement of studied specimen is to characterize the variation of Raman mode as function of composition and possible Raman active hydroxyl-related modes. In this meeting the results will be presented and discussed.

Modulation of Pancreatic Islets' Function and Survival During Aging Involves the Differential Regulation of Endoplasmic Reticulum Stress by p21 and CHOP.

PubMed

Mihailidou, Chrysovalantou; Chatzistamou, Ioulia; Papavassiliou, Athanasios G; Kiaris, Hippokratis

2017-08-01

Although endoplasmic reticulum (ER) stress is recognized as a major mechanism causing pancreatic dysfunction in diabetes, little is known on how aging modulates the process. Here, we compared the response with ER stress, viability, and insulin release from pancreatic islets of young (6 weeks) or aged (14 months) mice. Islets from aged mice were more sensitive to ER stress than their younger counterparts; they exhibited more pronounced unfolded protein response (UPR) and caspase activation and displayed compromised insulin release after high-glucose stimulation. Genetic ablation of p21 sensitized the islets to ER stress, especially in the aged group, whereas CHOP ablation was protective for islets from both aged and younger animals. Ciclopirox (CPX), an iron chelator that stimulates p21 expression, protected islets from glucotoxicity and mice from diet-induced diabetes, especially in the aged group in a manner that was both p21 and CHOP dependent. For the first time, the study shows that age-dependent susceptibility to diet-induced diabetes is associated with the activity of p21 and CHOP in pancreatic islets and that CPX protects islets from glucotoxicity and mice from diabetes in an age-dependent manner. Our results identify ER stress as an age-dependent modifier of islet survival and function by mechanisms implicating enhancement of CHOP activity and inhibition of the protective activity of p21. These findings suggest that interventions restoring the homeostatic activity of ER stress, by agents such as CPX, may be particularly beneficial for the management of diabetes in the elderly. Antioxid. Redox Signal. 27, 185-200.

Water Content of the Oceanic Lithosphere at Hawaii from FTIR Analysis of Peridotite Xenoliths

NASA Technical Reports Server (NTRS)

Peslier, Anne H.; Bizmis, Michael

2013-01-01

Although water in the mantle is mostly present as trace H dissolved in minerals, it has a large influence on its melting and rheological properties. The water content of the mantle lithosphere beneath continents is better constrained by abundant mantle xenolith data than beneath oceans where it is mainly inferred from MORB glass analysis. Using Fourier transform infrared (FTIR) spectrometry, we determined the water content of olivine (Ol), clinopyroxene (Cpx) and orthopyroxene (Opx) in spinel peridotite xenoliths from Salt Lake Crater, Oahu, Hawaii, which are thought to represent fragments of the Pacific oceanic lithosphere that was refertilized by alkalic Hawaiian melts. Only Ol exhibits H diffusion profiles, evidence of limited H loss during xenolith transport to the surface. Water concentrations (Ol: 9-28 ppm H2O, Cpx: 246-566 ppm H2O, Opx: 116-224 ppm H2O) are within the range of those from continental settings but higher than those from Gakkel ridge abyssal peridotites. The Opx H2O contents are similar to those of abyssal peridotites from Atlantic ridge Leg 153 (170-230 ppm) but higher than those from Leg 209 (10- 14 ppm). The calculated bulk peridotite water contents (94 to 144 ppm H2O) are in agreement with MORB mantle source water estimates and lower than estimates for the source of Hawaiian rejuvenated volcanism (approx 540 ppm H2O) . The water content of Cpx and most Opx correlates negatively with spinel Cr#, and positively with pyroxene Al and HREE contents. This is qualitatively consistent with the partitioning of H into the melt during partial melting, but the water contents are too high for the degree of melting these peridotites experienced. Melts in equilibrium with xenolith minerals have H2O/Ce ratios similar to those of OIB

Drug Response and Resistance in Advanced NF1-Associated Cancers

DTIC Science & Technology

2014-05-01

principle to NF1-associated cancers. The standard treatment for AML involves administering high doses of cytarabine in combination with an...ultimately relapse despite receiving consolidation chemotherapy and/or HSCT. CPX-351 is a liposomal formulation that contains cytarabine and daunorubicin at

Drug Response and Resistance in Advanced NF1-Associated Cancers

DTIC Science & Technology

2013-04-01

administering high doses of cytarabine in combination with an anthracycline agent such as daunorubicin (51). These aggressive regimens induce remissions in...liposomal formulation that contains cytarabine and daunorubicin at an optimized ratio to enhance AML killing without added toxicity(52). CPX-351 in

Re-analysis of human immunodeficiency virus type 1 isolates from Cyprus and Greece, initially designated 'subtype I', reveals a unique complex A/G/H/K/? mosaic pattern.

PubMed

Paraskevis, D; Magiorkinis, M; Vandamme, A M; Kostrikis, L G; Hatzakis, A

2001-03-01

Human immunodeficiency virus type 1 (HIV-1) has been classified into three main groups and 11 distinct subtypes. Moreover, several circulating recombinant forms (CRFs) of HIV-1 have been recently documented to have spread widely causing extensive HIV-1 epidemics. A subtype, initially designated I (CRF04_cpx), was documented in Cyprus and Greece and was found to comprise regions of sequence derived from subtypes A and G as well as regions of unclassified sequence. Re-analysis of the three full-length CRF04_cpx sequences that were available revealed a mosaic genomic organization of unique complexity comprising regions of sequence from at least five distinct subtypes, A, G, H, K and unclassified regions. These strains account for approximately 2% of the total HIV-1-infected population in Greece, thus providing evidence of the great capability of HIV-1 to recombine and produce highly divergent strains which can be spread successfully through different infection routes.

Origin of mantle peridotite: Constraints from melting experiments to 16.5 GPa

NASA Astrophysics Data System (ADS)

Herzberg, Claude; Gasparik, Tibor; Sawamoto, Hiroshi

1990-09-01

Experimental data are reported for the melting of komatiite, peridotite, and chondrite compositions in the pressure range 5-16.5 GPa. All experiments were run using the multiple-anvil apparatus facilities at Nagoya and Stony Brook. Equilibrium between coexisting crystals and liquid is demonstrated to occur in less than 3 min in the 2100°C range. The anhydrous solidus in CaO-MgO-Al2O3-SiO2 has been calibrated and is shown to be about 100° higher than that for naturally occurring peridotite (KLB1). All melting curves have positive dT/dP. The effect of pressure is to expand the crystallization field of garnet at the expense of all other phases, resulting in a change in the liquidus phase from olivine to garnet at high pressures. The melting of rocks which contain the four crystalline phases olivine, orthopyroxene, clinopyroxene, and garnet is restricted to enstatite-rich compositions such as chondrite. For these it is demonstrated that melting is peritectic, rather than eutectic, and takes the form L+Opx = Ol+Cpx+Gt. Partial melting yields liquids with the following properties: 5 GPa for komatiite; and 10-15 GPa for liquid peridotite with about 40% MgO, but one that is unlike mantle peridotite in that it is distinctly enriched in silica. These results provide a test and refutation of the model that upper mantle peridotite originated by direct initial melting of a chondritic mantle (Herzberg and O'Hara, 1985). Unlike chondrite, partial melting of peridotite does not usually involve orthopyroxene. Instead, it occurs by the generation of ultrabasic liquids along a cotectic involving L+Ol+Cpx+Gt. Although the thermal and compositional characteristics of this cotectic have not been fully calibrated, it is very likely that it will degenerate into a thermal minimum (L+Ol+Cpx+Gt), compositionally similar to komatiite at 5 GPa and mantle peridotite at 10-15 GPa. Peridotite liquids that occupy a thermal minimum can be derived from those formed from the melting of chondrite by removal of orthopyroxene, followed by fractional crystallization of olivine, clinopyroxene, and garnet. The possibility exists that the thermal minimum is compositionally identical to mantle peridotite in the 10-15 GPa range. If this can be confirmed by experiment, the upper mantle can be understood as having originated by the fractional crystallization of peridotite liquids in a large-scale differentiation event, consistent with magma ocean models for an early Earth.

Magmatic Diversity of the Wehrlitic Intrusions in the Oceanic Lower Crust of the Northern Oman Ophiolite

NASA Astrophysics Data System (ADS)

Kaneko, R.; Adachi, Y.; Miyashita, S.

2014-12-01

The Oman ophiolite extends along the east coast of Oman, and is the world's largest and best-preserved slice of obducted oceanic lithosphere. The magmatic history of this ophiolite is complex and is generally regarded as having occurred in three stages (MOR magmatism, subduction magmatism and intraplate magmatism). Wehrlitic intrusions constitute an important element of oceanic lower crust of the ophiolite, and numerous intrusions cut gabbro units in the northern Salahi block of this ophiolite. In this study area, we identified two different types of wehrlitic intrusions. One type of the intrusions mainly consists of dunite, plagioclase (Pl) wehrlite and mela-olivine (Ol) gabbro, in which the crystallization sequence is Ol followed by the contemporaneous crystallization of Pl and clinopyroxene (Cpx). This type is called "ordinary" wehrlitic intrusions and has similar mineral compositions to host gabbros (Adachi and Miyashita 2003; Kaneko et al. 2014). Another type of the intrusions is a single intrusion that crops out in an area 250 m × 150 m along Wadi Salahi. This intrusion consists of Pl-free "true" wehrlite, in which the crystallization sequence is Ol and then Cpx. The forsterite contents (Fo%) of Ol from the "ordinary" wehrlitic intrusions and "true" wehrlitic intrusions have ranges of 90.8-87.0 (NiO = 0.36-0.13 wt%) and 84.7 (NiO = 0.31 wt%), respectively. Cr numbers (Cr#) of Cr-spinel from the "true" wehrlitic intrusions show higher Cr# value of 0.85 than those of the "ordinary" wehrlitic intrusions (0.48-0.64). But the former is characterized by very high Fe3+ values (YFe3+ = 0.49-0.68). Kaneko et al. (2014) showed that the "ordinary" ubiquitous type has similar features to MOR magmatism and the depleted type in the Fizh block (Adachi and Miyashita 2003) links to subduction magmatism. These types are distinguished by their mineral chemistries (TiO2 and Na2O contents of Cpx). The TiO2 and Na2O contents of Cpx from the "true" wehrlitic intrusions have 0.38 wt% and 0.26 wt%, respectively, and plot on the field of MOR magmatism. The most-evolved Ol (Fo% = 84.7) from the wehrlitic intrusions has high NiO (0.31 wt%) and plots on the olivine mantle array (Takahashi 1986). It is suggested that heterogeneity of source mantle influences the magmatic diversity of the wehrlitic intrusions.

Mesoproterozoic orangeites of Karelia (Kostomuksha-Lentiira): evidence for composition of mantle lithosphere

NASA Astrophysics Data System (ADS)

Kargin, Alexey; Nosova, Anna; Larionova, Yulia; Kononova, Voctoria; Borisovskiy, Sergey; Kovalchuk, Elena; Griboedova, Irina

2014-05-01

The 1.23-1.20 Ga old diamondiferous lamproites and orangeites (kimberlites of II group) of the Kostomuksha-Taloveys and the Lentiira-Kuhmo dyke fields intrude the Archaean crust of the Karelian craton, NE of the East European Platform. Mineral (a trend of compositional evolution of mica, presence of carbonate minerals in basis, composition of olivine) and geochemical (major elements, ratio of trace elements, primitive mantle normalized trace elements patterns) characteristics of these rocks suggest an orangeitic rather than lamproitic or lamprophyric nature. The composition of Phl-Ol orangeites suggests intensive processes of fractional crystallization for their melts. Cpx-Phl-Ol orangeites indicate higher intensity of lithospheric mantle assimilation then other orangeitic types. Phl-Carb orangeites of the Taloveys area and Cpx-Phl-Ol one of the Lentiira area are closest to primary melts. The Ol-Phl-Cpx orangeites of the Lentiira area contain three generations of unaltered olivine that vary in composition and origin: a) xenocryst derived from depleted mantle peridotite; b) orangeitic olivine phenocryst and c) and olivine like early stage crystallization of megacryst assemblage or a product of metasomatic interaction between mantle peridotite and protokimberlitic melt. Orangeites of Kostomuksha-Lentiira have low- and medium-radiogenic value of (87Sr/86Sr)1200 that range from 0.7038 to 0.7067. Phl-Carb orangeites of Taloveys have less radiogenic isotopic composition of Nd (eNd -11 ... -12) then Cpx-Phl-Ol and Phl-Ol orangeites of Kostomuksha (eNd -6.9 ... -9.4). The study of Sm-Nd and Rb-Sr isotopic systems suggests that an ancient metasomatic mantle source took part in origin of orangeites. We propose a two-steps model of origin of their source (Kargin et al., 2014): 1) The metasomatic component of mantle source (like as MARID-type veins) formed during Lapland-Kola and/or Svecofennian orogeny events (2.1-1.8 Ga ago). 2) The intrusion of orangeites is comparable by time and geological setting with back-arc extensions (such as magmatism of CSDG) during the first stage of Sveconorwegian orogeny, initial stage of assembly of the supercontinent Rodinia (1.31-1.14 Ga). These back-arc extensions inspired of asthenosphere-derived melts to metasomatic lithospheric mantle and a generation of orangeitic melts. Kargin A.V., Nosova A.A., Larionova Yu.O. et al. Mesoproterozoic orangeites (kimberlites II) of Western Karelia: mineralogical, geochemical and Nd-Sr isotopic-geochemical characteristics // Petrology. 2014. V.2. in press.

Heterogeneous source components of intraplate basalts from NE China induced by the ongoing Pacific slab subduction

NASA Astrophysics Data System (ADS)

Chen, Huan; Xia, Qun-Ke; Ingrin, Jannick; Deloule, Etienne

2016-04-01

In recent few years, the recycled oceanic slab has been increasingly suggested to be the enriched component in the mantle source of widespread intra-plate small-volume basaltic magmatism in eastern China. The recycled oceanic slab is a mixture of sediment, upper oceanic crust and lower gabbro oceanic crust, and will undergo alteration and dehydration during the recycling progress. The influence of these different components on the mantle source needs to be further constrained. The Chaihe-aershan volcanic field in Northeast China is located close to the surface position of the front edge of the subducted Pacific slab and includes more than 35 small-volume Quaternary basaltic volcanoes, which provides an opportunity to study the evolution of mantle source in detail and the small-scale geochemical heterogeneity of the mantle source. We measured the oxygen isotopes and water content of clinopyroxene (cpx) phenocrysts by secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectrometry (FTIR), respectively. The water content of magma was then estimated based on the partition coefficient of H2O between cpx and basaltic melt. The measured δ18O of cpx phenocrysts (4.27 to 8.57) and the calculated H2O content of magmas (0.23-2.70 wt.%) show large variations, reflecting the compositional heterogeneity of the mantle source. The δ18O values within individual samples also display a considerable variation, from 1.28 to 2.31‰ suggesting mixing of magmas or the sustained injection of magmas with different δ18O values during the crystallization. The relationship between the averaged δ18O values of cpx phenocrysts and the H2O/Ce, Ba/Th, Nb/La ratios and Eu anomaly of whole-rocks demonstrates the contribution to three components in the mantle source (hydrothermally altered upper oceanic crust or marine sediments, altered lower gabbroic oceanic crust, ambient mantle). The proportions of these three components varied strongly within a limited period (˜1.27 Ma to ˜0.25 Ma). As only the Pacific slab is constantly subducted to the eastern Asia during that time, we suggested that its ongoing subduction is the only reasonable candidate to result in the compositional heterogeneity and rapid variation of enriched components in such a limited and recent time. Combines with previous studies on other basalt localities of eastern China, these new results confirm that the Pacific slab subduction play a key role in the triggering of the wide spread Cenozoic basaltic volcanism in eastern China.

Discovery of novel inhibitors of the NorA multidrug transporter of Staphylococcus aureus.

PubMed

Brincat, Jean Pierre; Carosati, Emanuele; Sabatini, Stefano; Manfroni, Giuseppe; Fravolini, Arnaldo; Raygada, Jose L; Patel, Diixa; Kaatz, Glenn W; Cruciani, Gabriele

2011-01-13

Four novel inhibitors of the NorA efflux pump of Staphylococcus aureus, discovered through a virtual screening process, are reported. The four compounds belong to different chemical classes and were tested for their in vitro ability to block the efflux of a well-known NorA substrate, as well as for their ability to potentiate the effect of ciprofloxacin (CPX) on several strains of S. aureus, including a NorA overexpressing strain. Additionally, the MIC values of each of the compounds individually are reported. A structure-activity relationship study was also performed on these novel chemotypes, revealing three new compounds that are also potent NorA inhibitors. The virtual screening procedure employed FLAP, a new methodology based on GRID force field descriptors.

Organometallic conjugates of the drug sulfadoxine for combatting antimicrobial resistance

USDA-ARS?s Scientific Manuscript database

Fourteen new RuII, RhIII and IrIII complexes conjugated to the antimalarial drug sulfadoxine functionalised with either a pyridylimino- or quinolylimino- group to allow N,N’-chelation ligands have been synthesized and characterized. The effect of the arene/Cpx, planarity of imino group on sulfadoxin...

Growth of early continental crust by water-present eclogite melting in subduction zones

NASA Astrophysics Data System (ADS)

Laurie, A.; Stevens, G.

2011-12-01

The geochemistry of well preserved Paleo- to Meso-Archaean Tonalite-Trondhjemite-Granodiorite (TTG) suite rocks, such as the ca 3.45 Ga trondhjemites from the Barberton greenstone belt in South Africa, provides insight into the origins of Earth's early felsic continental crust. This is particularly well demonstrated by the high-Al2O3 variety of these magmas, such as the Barberton rocks, where the geochemistry requires that they are formed by high pressure (HP) melting of a garnet-rich metamafic source. This has been interpreted as evidence for the formation of these magmas by anatexis of the upper portions of slabs within Archaean subduction zones. Most of the experimental data relevant to Archaean TTG genesis has been generated by studies of fluid-absent melting of metabasaltic sources. However, water drives arc magmatism within Phanerozoic subduction zones and thus, understanding the behaviour of water in Archaean subduction zones, may have considerable value for understanding the genesis of these TTG magmas. Consequently, this study investigates the role of HP water-present melting of an eclogite-facies starting material, in the production of high-Al2O3 type TTG melts. Water-saturated partial melting experiments were conducted between 1.9 and 3.0GPa; and, 870°C and 900°C. The melting reaction is characterized by the breakdown of sodic Cpx, together with Qtz and H2O, to form melt in conjunction with a less sodic Cpx: Qtz + Cpx1 + Grt1 + H2O = Melt + Cpx2 + Grt2. In many of the experimental run products, melt segregated efficiently from residual crystals, allowing for the measurement of a full range of trace elements via Laser Ablation Inductively Coupled Plasma Mass Spectroscopy. The experimental glasses produced by this study have the compositions of peraluminous trondhjemites; and they are light rare earth element, Zr and Sr enriched; and heavy rare earth element, Y and Nb depleted. The compositions of the experimental glasses are similar to high-Al2O3 type Archaean TTG rocks in general and similar to the Barberton trondhjemites in particular. Additionally, due to Cpx being a major reactant, Ni and Cr contents of the glasses are high and match those of high-Al2O3 type TTG compositions. This challenges the notion that this aspect of TTG geochemistry indicates interaction of the magma with the mantle wedge. Consequently, we propose that water-present melting of an eclogitic source is a viable mechanism for the genesis of Paleo- to Meso-Archaean felsic continental crust. Importantly, this mechanism of TTG formation involves the upper surface of the subducting slab acting as an anatectic capture site for metamorphic fluid which evolved from cooler domains slightly deeper within the hydrated upper portion of the slab. This explains both TTG genesis and the lack of characteristic products of mantle wedge metasomatism, such as andesites, concurrent with TTG magmatism of this type during the Paleo- to Meso-Archaean. Cooling of the upper mantle by only a small amount towards to end of the Archaean Eon acted to "turn off" water-present melting of the slab, allowing water to metasomatise the mantle wedge and induce calc-alkaline magmatism in association with volcanic arcs.

Origin Of Pyroxenites From San Jorge And Santa Isabel (Solomon Islands).

NASA Astrophysics Data System (ADS)

Berly, T.

2001-12-01

The Solomon Islands are a NW to SE-trending double chain of islands, the older basement of which was formed by SW-directed subduction of the Pacific Plate beneath the Indo-Australian Plate, between the Eocene and Early Miocene. At 10 Ma, the Ontong Java Plateau (OJP) collided with the Solomon arc, and in response to this collision, a polarity reversal of subduction occurred; NE-directed subduction beneath the Solomon arc began. Consequent to this collision, thin fault slices of peridotites, pyroxenites, gabbros, and basalts, some of which are demonstrably obducted OJP, are now exposed in SE Santa Isabel and neighbouring San Jorge. The pyroxenites are associated with harzburgites, dunites and sometimes incorporated into serpentine massifs (NW San Jorge). These fresh, coarse-grained rocks contain variable proportions of orthopyroxene (70

Sub-inhibitory concentrations of penicillin G induce biofilm formation by field isolates of Actinobacillus pleuropneumoniae.

PubMed

Hathroubi, S; Fontaine-Gosselin, S-È; Tremblay, Y D N; Labrie, J; Jacques, M

2015-09-30

Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This is a highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in swine production and these antibiotics are associated with high systemic clearance and low oral bioavailability. This may expose A. pleuropneumoniae to sub-inhibitory concentrations of penicillin G when the antibiotic is administered orally. Our goal was to evaluate the effect of sub-minimum inhibitory concentration (MIC) of penicillin G on the biofilm formation of A. pleuropneumoniae. Biofilm production of 13 field isolates from serotypes 1, 5a, 7 and 15 was tested in the presence of sub-MIC of penicillin G using a polystyrene microtiter plate assay. Using microscopy techniques and enzymatic digestion, biofilm architecture and composition were also characterized after exposure to sub-MIC of penicillin G. Sub-MIC of penicillin G significantly induced biofilm formation of nine isolates. The penicillin G-induced biofilms contained more poly-N-acetyl-D-glucosamine (PGA), extracellular DNA and proteins when compared to control biofilms grown without penicillin G. Additionally, penicillin G-induced biofilms were sensitive to DNase which was not observed with the untreated controls. Furthermore, sub-MIC of penicillin G up-regulated the expression of pgaA, which encodes a protein involved in PGA synthesis, and the genes encoding the envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs of penicillin G significantly induce biofilm formation and this is likely the result of a cell envelope stress sensed by the CpxRA system resulting in an increased production of PGA and other matrix components. Copyright © 2015 Elsevier B.V. All rights reserved.

UHT overprint of HP rocks? A case study from the Adula nappe complex (Central Alps, N Italy)

NASA Astrophysics Data System (ADS)

Tumiati, Simone; Zanchetta, Stefano; Malaspina, Nadia; Poli, Stefano

2014-05-01

The Adula-Cima Lunga nappe complex is located on the eastern flank of the Lepontine Dome and represents the highest of the Lower Penninic units of the Central Alps. The Adula nappe largely consists of orthogneiss and paragneiss of pre-Mesozoic origin, variably retrogressed eclogites preserved as boudins within paragneiss, minor ultramafic bodies and metasedimentary rocks of presumed Mesozoic age. The higher metamorphic conditions have been estimated for the peridotite lenses in the southern part of the nappe at pressure over 3.0 GPa and temperature of 800-850°C. Garnet lherzolite bodies crop out at three localities, from west to east: Cima di Gagnone, Alpe Arami and Mt. Duria. After the partial subduction of the European distal margin beneath the Africa-Adria margin, the HP rocks were overprinted by an upper amphibolite facies metamorphism that postdates the main phase of nappe stacking. In the southern sector of the Lepontine Dome, adjacent to the Insubric Fault, metamorphic conditions promoted extensive migmatization of both metasedimentary and metagranitoid rocks. In one single outcrop, at Monte Duria, garnet lherzolites occur in m-sized boudins hosted within partly granulitized amphibole-bearing and k-feldspar gneisses that contain also some decimeter-sized boudins of both mafic and metapelitic eclogites. This rock association is in turn embedded within the migmatitic gneisses that form most of the southern sector of the Adula nappe. Petrographic and chemical analyses indicate that garnet peridotite is composed of olivine (XMg=0.88), orthopyroxene, clinopyroxene and garnet (Py68; Cr2O3 up to 1.45 wt%) with inclusions of Cr-rich spinel (up to Cr/(Al+Cr)=0.55) surrounded by kelyphitic symplectites of opx + cpx/amph + spl. These reaction produced double coronas, one composed of opx (former ol) and one composed of cpx + opx+ spl. In one kelyphite, we observed the uncommon occurrence of ZrO2 (baddeleyite) and ZrTi2O6 (srilankite). Tiny crystals of these two Zr-bearing phases (˜1 μm) are invariably located in the opx corona after ol. The cpx + opx + spl corona (after grt) contains, instead, zircon. Baddeleyite should have formed through a reaction of the type Mg2SiO4 + ZrSiO4 = MgSiO3 + ZrO2. ZrO2 and ZrTi2O6 display a low amount of solid solution. These compositions are consistent with T below 1200°C, but an improvement of the thermodynamic model is needed in order to better constrain the T of the granulitic overprint on the basis of these Zr-bearing phases. In mafic eclogites, the HP association consists of garnet (Py40Alm37Sp20), omphacite (preserved as inclusion, containing Jd30 and Mg# 0.87), kyanite and minor quartz. Omphacite is almost always replaced by cpx (Jd5) + plag (An55) symplectites. Garnet is surrounded by plag (An33) + opx (En70) symplectites. Kyanite is replaced by plag (An84) + spinel + sapphirine. The spinel-sapphirine Fe-Mg thermometer suggests T of about 850°C due to granulite-facies overprint. We observed sapphirine associated with cpx + opx + plag also in kelyphites after garnet in clinopyroxenites. In eclogitic metapelites, kyanite is replaced by a corundum + anorthite ± spinel assemblage. A corundum-rich layer occurs between eclogites and the host gneiss. Cm-sized emerald green zoisite in this layer is replaced by anorthitic plagioclase ± cpx ± spinel ± calcite. The observed assemblages point to a diffuse granulitization of both the peridotites and the hosting HP rocks of Mt. Duria, suggesting a nearly isothermal decompression from peak-pressure conditions. The surrounding migmatitic gneiss do not display evidence of such granulitic event, having been formed at T<700°C. The mechanism and timing of emplacement of the garnet peridotite and associated HP-HT rocks in the country migmatites, and whether or not the subduction event is related to the Alpine or to an older orogenic cycle are still a matter of debate.

[Application of the 6-Minute Walking Test and Shuttle Walking Test in the Exercise Tests of Patients With COPD].

PubMed

Ho, Chiung-Fang; Maa, Suh-Hwa

2016-08-01

Exercise training improves the management of stable chronic obstructive pulmonary disease (COPD). COPD patients benefit from exercise training programs in terms of improved VO2 peak values and decreased dyspnea, fatigue, hospital admissions, and rates of mortality, increasing exercise capacity and health-related quality of life (HRQOL). COPD is often associated with impairment in exercise tolerance. About 51% of patients have a limited capacity for normal activity, which often further degrades exercise capacity, creating a vicious circle. Exercise testing is highly recommended to assess a patient's individualized functions and limitations in order to determine the optimal level of training intensity prior to initiating an exercise-training regimen. The outcomes of exercise testing provide a powerful indicator of prognosis in COPD patients. The six-minute walking test (6MWT) and the incremental shuttle-walking test (ISWT) are widely used in exercise testing to measure a patient's exercise ability by walking distances. While nursing-related articles published in Taiwan frequently cite and use the 6MWT to assess exercise capacity in COPD patients, the ISWT is rarely used. This paper introduces the testing method, strengths and weaknesses, and application of the two tests in order to provide clinical guidelines for assessing the current exercise capacity of COPD patients.

Examining physiotherapist use of structured aerobic exercise testing to decrease barriers to aerobic exercise.

PubMed

Foster B Sc, Evan; Fraser, Julia E; Inness PhD, Elizabeth L; Munce, Sarah; Biasin, Louis; Poon, Vivien; Bayley, Mark

2018-04-03

To determine the frequency of physiotherapist-administered aerobic exercise testing/training, the proportion of physiotherapists who administer this testing/training, and the barriers that currently exist across different practice environments. A secondary objective is to identify the learning needs of physiotherapists for the development of an education curriculum in aerobic exercise testing and training with electrocardiograph (ECG) administration and interpretation. National, cross-sectional survey. Registered physiotherapists practicing in Canada. Out of 137 participants, most (75%) physiotherapists prescribed aerobic exercise on a regular basis (weekly); however, 65% had never conducted an aerobic exercise test. There were no significant differences in frequency of aerobic exercise testing across different practice environments or across years of physiotherapy experience. Physiotherapists perceived the main barriers to aerobic exercise testing as being a lack of equipment/space (78%), time (65%), and knowledge (56%). Although most (82%) were uncomfortable administering 12-lead ECG-monitored aerobic exercise tests, 60% stated they would be interested in learning more about ECG interpretation. This study found that physiotherapists are regularly implementing aerobic exercise. This exercise was infrequently guided by formal aerobic exercise testing, which could increase access to safe and effective exercise within the optimal aerobic training zone. As well, this could facilitate training in patients with cardiovascular diagnoses that require additional testing for medical clearance. Increased ECG training and access to equipment for physiotherapists may augment pre-screening aerobic exercise testing. This training should include learning the key arrhythmias for aerobic exercise test termination as defined by the American College of Sports Medicine.

Erratum: Correction to: Water in the Earth's Interior: Distribution and Origin

NASA Astrophysics Data System (ADS)

Peslier, Anne H.; Schönbächler, Maria; Busemann, Henner; Karato, Shun-Ichiro

2017-10-01

Correction to: Space Sci Rev DOI: 10.1007/s11214-017-0387-z This article has been corrected. Figure 3 was initially published with erroneous axis titles in Fig. 3B and 3D where the x axis should be Cpx H2O, instead of Grt H2O.

Low-Cost ASDE Evaluation Report: Raytheon Marine (Phase I) Radar at MKE (ARPA M345O/18CPX-19), Volume I.

DOT National Transportation Integrated Search

1996-07-31

The FAA has identified the Airport Surface Detection Equipment as a radar system that aids air traffic controllers in low visibility conditions to detect surface radar targets and sequence aircraft movement on active runways. Though 35 major U.S. air...

Experimental study of eclogitization and melting of basic rocks at P = 4 GPa and T = 1200-1400°C

NASA Astrophysics Data System (ADS)

Gorbachev, N. S.; Shapovalov, Yu. B.; Kostyuk, A. V.

2017-06-01

Experimental study of gabbro-norite eclogitization and melting at P = 4 GPa has made it possible to reveal the effective influence of fluid and temperature on the phase relationships. The melt composition varies from andesite-dacite in "dry conditions" to phonolite and carbonate in the presence of a fluid. The Grt-containing melting curve is replaced by the Cpx-containing liquidus as the temperature changes or a fluid is added. Hence, the possible presence of "garnetitite" and "clinopyroxenite" in the upper mantle was proved experimentally. The ultimate pressure of the spinel facies at the depth of the eclogite upper mantle is controlled by the stability of Cht ≤ 4 GPa. The revealed similarity of the spectra of REE-adakite, tonalite-trondhjemite-granodiorite (TTG), and melts formed under the partial melting of eclogitized gabbro-norite does not contradict the existing ideas of the eclogite source of the TTG rocks. Wide variations in the interphase microelement distribution factors D (Grt, Cpx)/L are indicative of effective fractionation of the microelements in the course of eclogite melting and differentiation.

Extreme isotopic variations in the upper mantle: evidence from Ronda

NASA Astrophysics Data System (ADS)

Reisberg, Laurie; Zindler, Alan

1986-12-01

The Ronda Ultramafic Complex in southern Spain represents a piece of the Earth's mantle which has been tectonically emplaced into the crust. Nd and Sr isotopic analyses are presented for leached, hand-picked Cr-diopside separates prepared from 15 rock and 18 river sediment samples from Ronda. These results demonstrate that within this small, contiguous body there exists the entire range of Nd isotopic compositions, and much of the range of Sr compositions, found in rocks derived from the sub-oceanic mantle. The sediment cpx samples show that the average isotopic composition of the massif becomes progressively less "depleted" moving from SW to NE along the long axis of the massif. The rock cpx samples document 143Nd/ 144Nd variations from 0.5129 to 0.5126 and 87Sr/ 86Sr variations from 0.7031 to 0.7039 within a uniform outcrop less than 10 m in extent. Thus, extreme isotopic fluctuations exist over a wide range of wavelengths. Sr and Nd isotopes are generally inversely correlated, forming a trend on a Nd-Sr diagram that sharply crosscuts that of the "mantle array". Many of the 143Nd/ 144Nd values, and all of the Sm/Nd values, from one section of the massif are lower than that SCV015SCV0 of the bulk earth, implying that this region existed, or was influenced by a component which existed, in a LREE-enriched environment for a significant period of time. Among the sediment cpxs there is a positive correlation between 143Nd/ 144Nd and 147Sm/ 144Nd. The rock cpx separates display considerably more scatter. A simple, single-stage differentiation event starting with a uniform mantle source cannot explain these results. At least one episode of mixing with a LREE-enriched component is required. If these results from Ronda are typical of the upper mantle, basalts with different isotopic compositions need not derive from spatially separated mantle sources.

Mantle Wedge formation during Subduction Initiation: evidence from the refertilized base of the Oman ophiolitic mantle

NASA Astrophysics Data System (ADS)

Prigent, C.; Guillot, S.; Agard, P.; Godard, M.; Lemarchand, D.; Ulrich, M.

2015-12-01

Although the Oman ophiolite is classically regarded as being the direct analog of oceanic lithosphere created at fast spreading ridges, the geodynamic context of its formation is still highly debated. The other alternative end-member model suggests that this ophiolite entirely formed in a supra-subduction zone setting. The latter one is supported by studies on volcanic sequences whereas studies dealing on the mantle section do not involve a significant influence of subduction processes on its structure and composition. We herein focus on basal peridotites from all along the ophiolite strike in order to decipher and characterize potential fluid/melt transfers relate to subduction processes. Samples were taken across the basal banded unit directly overlying the amphibolitic/granulitic metamorphic sole which represents an accreted part of the lower plate. We carried out a petrological, structural and geochemical study on these rocks and their constitutive minerals. Our results show that basal peridotites range from lherzolites to highly depleted harzburgites in composition. Clinopyroxenes (cpx) display melt impregnation textures and co-crystallized with HT/HP amphiboles (amph), spinels and sulfurs. Major and trace elements of the constitutive minerals indicate that these minerals represent trapped incremental partial melt after hydrous melting. Different cpx-bearing lithologies then result from varying degrees of partial melting and melt extraction. Combined with Boron isotopic data, we demonstrate that fluids responsible for hydrous melting of these ophiolitic basal peridotites are subduction-related, most likely derived from dehydration of the metamorphic sole during its formation in subduction initiation. From these observations and thermal constraints, we interpret the occurrence of these basal lherzolites as representing a freezing front developed by thermal re-equilibration (cooling) during subduction processes: subduction-related hydrous partial melts were extracted at different degrees until getting ultimately trapped, and crystallized cpx, amph and other associated minerals. If our interpretation is correct, the base of the Oman ophiolite could provide the best proxy for the composition of a frozen-in, incipiently forming mantle wedge.

Half-sandwich rhodium(III) transfer hydrogenation catalysts: Reduction of NAD(+) and pyruvate, and antiproliferative activity.

PubMed

Soldevila-Barreda, Joan J; Habtemariam, Abraha; Romero-Canelón, Isolda; Sadler, Peter J

2015-12-01

Organometallic complexes have the potential to behave as catalytic drugs. We investigate here Rh(III) complexes of general formula [(Cp(x))Rh(N,N')(Cl)], where N,N' is ethylenediamine (en), 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen) or N-(2-aminoethyl)-4-(trifluoromethyl)benzenesulfonamide (TfEn), and Cp(x) is pentamethylcyclopentadienyl (Cp*), 1-phenyl-2,3,4,5-tetramethylcyclopentadienyl (Cp(xPh)) or 1-biphenyl-2,3,4,5-tetramethyl cyclopentadienyl (Cp(xPhPh)). These complexes can reduce NAD(+) to NADH using formate as a hydride source under biologically-relevant conditions. The catalytic activity decreased in the order of N,N-chelated ligand bpy > phen > en with Cp* as the η(5)-donor. The en complexes (1-3) became more active with extension to the Cp(X) ring, whereas the activity of the phen (7-9) and bpy (4-6) compounds decreased. [Cp*Rh(bpy)Cl](+) (4) showed the highest catalytic activity, with a TOF of 37.4±2h(-1). Fast hydrolysis of the chlorido complexes 1-10 was observed by (1)H NMR (<10min at 310K). The pKa* values for the aqua adducts were determined to be ca. 8-10. Complexes 1-9 also catalysed the reduction of pyruvate to lactate using formate as the hydride donor. The efficiency of the transfer hydrogenation reactions was highly dependent on the nature of the chelating ligand and the Cp(x) ring. Competition reactions between NAD(+) and pyruvate for reduction by formate catalysed by 4 showed a preference for reduction of NAD(+). The antiproliferative activity of complex 3 towards A2780 human ovarian cancer cells increased by up to 50% when administered in combination with non-toxic doses of formate, suggesting that transfer hydrogenation can induce reductive stress in cancer cells. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Activation of deltaF508 CFTR in a cystic fibrosis respiratory epithelial cell line by 4-phenylbutyrate, genistein and CPX.

PubMed

Andersson, C; Roomans, G M

2000-05-01

The cellular basis of cystic fibrosis (CF) is a defect in a cyclic adenosine monophosphate (cAMP)-activated chloride channel (CF transmembrane conductance regulator) in epithelial cells that leads to decreased chloride ion transport and impaired water transport across the cell membrane. This study investigated whether it was possible to activate the defective chloride channel in cystic fibrosis respiratory epithelial cells with 4-phenylbutyrate (4PBA), genistein and 8-cyclopentyl-1,3-dipropylxanthine (CPX). The CF bronchial epithelial cell line CFBE41o-, which expresses the deltaF508 mutation, was treated with these agents and loss of Cl-, indicating Cl- efflux, measured by X-ray microanalysis. 8-bromo-cAMP alone did not induce Cl- efflux in CFBE41o- cells, but after incubation with 4PBA a significant efflux of Cl- occurred. Stimulation of cells with a combination of genistein and cAMP also induced Cl- efflux, whereas a combination of pretreatment with 4PBA and a combined stimulation with genistein and cAMP induced an even larger Cl- efflux. Cl- efflux could also be stimulated by CPX, but this effect was not enhanced by 4PBA pretreatment. The deltaF508 mutation leads to impaired processing of the cystic fibrosis transmembrane conductance regulator. The increased efflux of chloride after 4-phenylbutyrate treatment can be explained by the fact that 4-phenylbutyrate allows the deltaF508 cystic fibrosis transmembrane conductance regulator to escape degradation and to be transported to the cell surface. Genistein and 8-cyclopentyl-1,3-dipropylxanthine act by stimulating chloride ion efflux by increasing the probability of the cystic fibrosis transmembrane conductance regulator being open. The combination of 4-phenylbutyrate and genistein may be useful in a potential pharmacological therapy for cystic fibrosis patients with the deltaF508 mutation.

Crystallization Conditions at Cascade and Other Arc Volcanoes: The Role of Recharge, and Ultimate, Proximal and Immediate Causes of Eruption

NASA Astrophysics Data System (ADS)

Putirka, K. D.

2016-12-01

A number of hypotheses have been offered to explain why volcanoes erupt. These include magma mixing, mafic recharge, or partial crystallization, any of which can drive parts or all of a system to vapor saturation, and so add to a magma's buoyancy. Age dates indicate long pre-eruption storage times for felsic magmas erupted at arcs, indicating that mafic recharge magmas, which can reinvigorate such systems, is a possible eruption trigger. However, plutonic systems reveal numerous recharge events that have no obvious ties to eruption (Coint et al. 2013; Putirka et al. 2014). And crystallization conditions at some arc systems support the implicit view, that recharge might be a necessary, but not a sufficient condition for eruption. At several Cascade volcanoes, Cpx and Amp crystals record coolings of 100-300oC. The Cpx grains derive exclusively from mafic enclaves, while Amp grains derive from both host and enclave materials. These considerable coolings call for a time lag following recharge, and indicate that vapor saturation is a proximal, although not necessarily an immediate cause of eruption. But we cannot discount recharge altogether. At the Cascades and at other arcs, Cpx crystalizes throughout the middle and upper crust, mostly from the surface down to 15 km. And high Fo olivine grains provide evidence for very hot magmas that intrude the upper mantle and lower crust, and possibly the middle crust, if hydrous. Volcanic pathways thus clearly extend into the middle crust, and at times, well below the Moho. It is unclear to what extent these deep pathways are hydraulically connected to the surface, or the role of deep-seated processes in initiating or sustaining eruptions. Progress in understanding these pathways, and triggering mechanisms, requires our differentiating "ultimate", "proximal" and "immediate" causes, and determining which of various magmatic processes provide necessary or sufficient conditions for eruption.

Partitioning of Cu between mafic minerals, Fe-Ti oxides and intermediate to felsic melts

NASA Astrophysics Data System (ADS)

Liu, Xingcheng; Xiong, Xiaolin; Audétat, Andreas; Li, Yuan

2015-02-01

This study used improved capsule technique i.e., Pt95Cu05 or Au95Cu05 alloy capsules as Cu sources to determine Cu partitioning between mafic minerals, Fe-Ti oxides and intermediate to felsic melts at 0.5-2.5 GPa, 950-1100 °C and various oxygen fugacities (fO2). In combination with the data from the mafic composition systems, the results demonstrate that Cu is generally highly incompatible in mafic minerals and moderately incompatible to compatible in Fe-Ti oxides. The general order of mineral/melt Cu partition coefficients (DCu) is garnet (0.01-0.06) ⩽ olivine (0.04-0.20) ≈ opx (0.04-0.24) ≈ amphibole (0.04-0.20) ⩽ cpx (0.04-0.45) ⩽ magnetite, titanomagnetite and Cr-spinel (0.18-1.83). The variations in DCu depend mainly on temperature, fO2 or mineral composition. In general, DCu for olivine (and perhaps opx) increases with decreasing temperature and increasing fO2. DCu increases for cpx with Na+ (pfu) in cpx, for magnetite and Cr-spinel with Fe3+ (pfu) in these phases and for titanomagnetite with Ti4+ (pfu) in this phase. The large number of DCu data (99 pairs) serves as a foundation for quantitatively understanding the behavior of Cu during magmatic processes. The generation of intermediate to felsic magmas via fractional crystallization or partial melting of mafic rocks (magmas) at deep levels of crust involves removal of or leaving assemblages of mafic minerals + Fe-Ti oxides ± sulfides. With our DCu data on mafic minerals and Fe-Ti oxides, DCubulk values around 0.2 were obtained for the sulfide-free assemblages. Cu will thus be concentrated efficiently in the derived melts during these two processes if sulfides are absent or negligible, explaining that high fO2 and sulfide-destabilization are favorable to formation of the porphyry Cu system.

Exercise stress test

MedlinePlus

Exercise ECG; ECG - exercise treadmill; EKG - exercise treadmill; Stress ECG; Exercise electrocardiography; Stress test - exercise treadmill; CAD - treadmill; Coronary artery disease - treadmill; Chest pain - treadmill; Angina - treadmill; ...

Acute Effects of 30 Minutes Resistance and Aerobic Exercise on Cognition in a High School Sample.

PubMed

Harveson, Andrew T; Hannon, James C; Brusseau, Timothy A; Podlog, Leslie; Papadopoulos, Charilaos; Durrant, Lynne H; Hall, Morgan S; Kang, Kyoung-Doo

2016-06-01

The purpose of this study was to determine differences in cognition between acute bouts of resistance exercise, aerobic exercise, and a nonexercise control in an untrained youth sample. Ninety-four participants performed 30 min of aerobic exercise, resistance exercise, or nonexercise separated by 7 days each in a randomized crossover design. After each exercise intervention, participants were assessed using 2 cognitive tests. The Dot, Word, and Color elements of the Stroop Test (Victoria version) and Parts A and B of the Trail-Making Test were used to measure cognition. Acute resistance and aerobic exercise resulted in similar improvements over nonexercise in all forms of the Stroop Test. Acute aerobic exercise led to improved performance over nonexercise and resistance exercise in Part B of the Trail-Making Test. Neither exercise intervention showed significant changes in time to complete Part A of the Trail-Making Test. Boys outperformed girls on the Stroop Dot and Color Test following acute aerobic exercise, in the Stroop Dot, Word, and Color Test following acute resistance exercise, and in the Stroop Color Test and Trail-Making Test Part B following nonexercise. Both acute resistance and aerobic exercise increased measures of cognition over a nonexercise control in untrained high school youth. These findings suggest the merits of acute resistance exercise as an alternative or complement to aerobic activity for educators aiming to increase youth physical activity and cognitive function concurrently.

Heterogeneous source components of intraplate basalts from NE China induced by the ongoing Pacific slab subduction

NASA Astrophysics Data System (ADS)

Chen, Huan; Xia, Qun-Ke; Ingrin, Jannick; Deloule, Etienne; Bi, Yao

2017-02-01

The subduction of oceanic slabs is widely accepted to be a main reason for chemical heterogeneities in the mantle. However, determining the contributions of slabs in areas that have experienced multiple subduction events is often difficult due to possible overlapping imprints. Understanding the temporal and spatial variations of source components for widespread intraplate small volume basalts in eastern China may be a basis for investigating the influence of the subducted Pacific slab, which has long been postulated but never confirmed. For this purpose, we investigated the Chaihe-aershan volcanic field (including more than 35 small-volume Quaternary basaltic volcanoes) in NE China and measured the oxygen isotopes and water content of clinopyroxene (cpx) phenocrysts using secondary ion mass spectrometry (SIMS) and Fourier transform infrared spectroscopy (FTIR), respectively. The water content of magma was then estimated based on the partition coefficient of H2O between cpx and the basaltic melt. The δ18O of cpx phenocrysts (4.28‰ to 8.57‰) and H2O content of magmas (0.19 wt.%-2.70 wt.%) show large variations, reflecting the compositional heterogeneity of the mantle source. The δ18O values and H2O content within individual samples also display considerable variation, suggesting the mixing of magmas and that the magma mixing occurred shortly before the eruption. The relation between the δ18O values of cpx phenocrysts and the H2O/Ce ratio, Ba/Th ratio and Eu anomaly of whole rocks demonstrates the contributions of three components to the mantle source (hydrothermally altered upper oceanic crust and marine sediments, altered lower gabbroic oceanic crust, and ambient mantle). The proportions of these three components have varied widely over time (∼1.37 Ma to ∼0.25 Ma). The Pacific slab is constantly subducted under eastern Asia and continuously transports recycled materials to the deep mantle. The temporal heterogeneity of the source components may be caused by ongoing Pacific slab subduction. Combined with other basalt localities in eastern China (Shuangliao basalts, Taihang basalts and Shangdong basalts), the contributions of recycled oceanic components in their mantle source are heterogeneous. This spatial heterogeneity of mantle sources may be induced by variable alterations and dehydration during the recycling process of the Pacific slab. Our results show that the source components of Cenozoic intraplate small-volume basalts in eastern China are temporally and spatially heterogeneous, which is likely induced by the ongoing subduction of the Pacific slab. This demonstrates that integrating the temporal variations in geochemical characteristics and tectonic history of a study region can identify the subducted oceanic plate that induced enriched components in the mantle source of intraplate basalts.

Anxiety responses to maximal exercise testing.

PubMed Central

O'Connor, P J; Petruzzello, S J; Kubitz, K A; Robinson, T L

1995-01-01

The influence of maximal exercise testing on state anxiety was examined in three separate studies. Highly trained male distance runners (Study 1, n = 12) as well as college students with average (Study 2, n = 16) and below average (Study 3, n = 32) physical fitness levels completed graded maximal exercise tests. This last group was also randomly assigned to either a control or an 8 week training programme in order to determine the effect of increased fitness on the psychological responses to maximal exercise testing. Physical fitness was determined by the measurement of maximal oxygen uptake. State anxiety (State-Trait Anxiety Inventory) was assessed before and from 2-15 min following exercise. It was found that the state anxiety responses to maximal exercise testing were not influenced by re-testing or by 8 weeks of endurance training. Across the three study groups, the anxiety response was variable during the first 5 min following exercise testing; increases, decreases and no changes in anxiety were observed when compared to pre-exercise levels. The anxiety response to maximal exercise appeared to be dependent on the pre-exercise anxiety levels as well as the timing of the post-exercise assessments. It is concluded that maximal exercise testing can be associated with negative mood shifts during the first 5 min after exercise; however, this response is transitory and followed by positive mood shifts 10-15 min following such tests. PMID:7551769

Alternatives to the Six-Minute Walk Test in Pulmonary Arterial Hypertension

PubMed Central

Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Saey, Didier; Maltais, François; Bonnet, Sébastien; Provencher, Steeve

2014-01-01

Introduction The physiological response during the endurance shuttle walk test (ESWT), the cycle endurance test (CET) and the incremental shuttle walk test (ISWT) remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. Methods Within two weeks, twenty-one PAH patients (mean age: 54(15) years; mean pulmonary arterial pressure: 42(12) mmHg) completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET) and CET) and three field tests (ISWT, ESWT and six-minute walk test (6MWT)). Physiological parameters were continuously monitored using the same portable telemetric device. Results Peak oxygen consumption (VO2peak) was similar amongst the five exercise tests (p = 0.90 by ANOVA). Walking distance correlated markedly with the VO2peak reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. Conclusion Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking) rather than the progression (endurance vs. incremental) of the exercise tests. PMID:25111294

Alternatives to the six-minute walk test in pulmonary arterial hypertension.

PubMed

Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Saey, Didier; Maltais, François; Bonnet, Sébastien; Provencher, Steeve

2014-01-01

The physiological response during the endurance shuttle walk test (ESWT), the cycle endurance test (CET) and the incremental shuttle walk test (ISWT) remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. Within two weeks, twenty-one PAH patients (mean age: 54(15) years; mean pulmonary arterial pressure: 42(12) mmHg) completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET) and CET) and three field tests (ISWT, ESWT and six-minute walk test (6MWT)). Physiological parameters were continuously monitored using the same portable telemetric device. Peak oxygen consumption (VO(2peak)) was similar amongst the five exercise tests (p = 0.90 by ANOVA). Walking distance correlated markedly with the VO(2peak) reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking) rather than the progression (endurance vs. incremental) of the exercise tests.

Software Sharing Enables Smarter Content Management

NASA Technical Reports Server (NTRS)

2007-01-01

In 2004, NASA established a technology partnership with Xerox Corporation to develop high-tech knowledge management systems while providing new tools and applications that support the Vision for Space Exploration. In return, NASA provides research and development assistance to Xerox to progress its product line. The first result of the technology partnership was a new system called the NX Knowledge Network (based on Xerox DocuShare CPX). Created specifically for NASA's purposes, this system combines Netmark-practical database content management software created by the Intelligent Systems Division of NASA's Ames Research Center-with complementary software from Xerox's global research centers and DocuShare. NX Knowledge Network was tested at the NASA Astrobiology Institute, and is widely used for document management at Ames, Langley Research Center, within the Mission Operations Directorate at Johnson Space Center, and at the Jet Propulsion Laboratory, for mission-related tasks.

Taking Yellowstone's Temperature: a New Clinopyroxene Geothermometer to Improve Timescales of Pre-eruptive Events

NASA Astrophysics Data System (ADS)

Brugman, K. K.; Till, C. B.

2017-12-01

The goal of our research is to quantify the time period between events in the magma chamber and eruption for the Scaup Lake rhyolite lava, as it erupted after a period of quiescence similar to what Yellowstone is experiencing today. The overarching goal of studies such as this that focus on past eruptions is to provide context and statistics that will ultimately improve volcano monitoring at different types of active volcanoes. The Scaup Lake flow contains zoned minerals (e.g., feldspar, zircon, clinopyroxene) that record multiple magma injection events shortly before they were erupted. Our previous work using nano-scale elemental concentration profiles from zoned clinopyroxene (cpx) as a diffusion dating tool reinforced our hypothesis that different minerals may not record the same series of pre-eruptive events, and that cpx crystal rims record older events in the Scaup Lake flow (on the order of 100s of years prior to eruption [Brugman et al., AGU OSPA talk, 2016]) than do feldspar rims (< 10 months and 10-40 years prior to eruption [Till et al., Geology, 2015]). In light of new temperature data, we have updated our diffusion dating results to better quantify pre-eruption timescales at Yellowstone.

Effectiveness of lectures attended via interactive video conferencing versus in-person in preparing third-year internal medicine clerkship students for Clinical Practice Examinations (CPX).

PubMed

Bertsch, Tania F; Callas, Peter W; Rubin, Alan; Caputo, Michael P; Ricci, Michael A

2007-01-01

The current practice in medical education is to place students at off-site locations. The effectiveness of these students attending remote lectures using interactive videoconferencing needs to be evaluated. To determine whether lecture content covering clinical objectives is learned by medical students located at remote sites. During the University of Vermont medicine clerkship, 52 medical students attended lectures both in person and via 2-way videoconferencing over a telemedicine network. The study used a crossover design, such that all students attended half of the lectures in person and half using videoconferencing. At the end of the clerkship, students were assessed via a Clinical Practice Examination (CPX), with each student completing 1 exam for material learned in person and 1 for material learned over telemedicine. Exam scores did not differ for the 2 lecture modes, with a mean score of 76% for lectures attended in person and a mean score of 78% for lectures attended via telemedicine (p = 0.66). Students learn content focused on clinical learning objectives as well using videoconferencing as they do in the traditional classroom setting.

In vivo imaging of cidofovir treatment of cowpox virus infection.

PubMed

Goff, Arthur; Twenhafel, Nancy; Garrison, Aura; Mucker, Eric; Lawler, James; Paragas, Jason

2007-09-01

Variola virus and other members of the genus Orthopoxviruses constitute a prominent bioterrorism and public health threat. Treatment with the anti-viral drug cidofovir inhibits replication of orthopoxviruses in vitro and in vivo. In this study, we visualized the effect of cidofovir on viral kinetics in orthopoxvirus infected mice by using whole-body fluorescence imaging (FI). We engineered a cowpox virus (CPV) expressing the enhanced green fluorescent protein (GFP). Single-step growth curves and calculated 50% lethal doses (LD(50)) of wild-type CPX (Wt-CPV) and GFP-expressing CPX (GFP-CPV) were comparable. Whole-body FI first detected GFP fluorescence in the mesenteric tissue of untreated animals on post-infection day (PID) 1. On PID 3 GFP signal was detected throughout the mesentery, in all abdominal organs by PID 5 and in most major organs, except for the heart and brain by PID 6. Infected animals treated with 25mg/kg of cidofovir also began showing signs of viral replication on PID 1, however, the fluorescent signal was limited only to discrete foci throughout the course of the infection. This work describes the first use of an established Orthopox model of infection to evaluate drug efficacy and track virus progression on a macroscopic level.

Interactions between ifenprodil and dizocilpine on mouse behaviour in models of anxiety and working memory.

PubMed

Fraser, C M; Cooke, M J; Fisher, A; Thompson, I D; Stone, T W

1996-11-01

The N-methyl-D-aspartate (NMDA) receptor polyamine site antagonist, ifenprodil, had no effect on spontaneous alteration or locomotor activity in the Y-maze when given alone. The NMDA receptor/ion channel blocker, dizocilpine, induced a deficit in spontaneous alteration, but when ifenprodil was co-administered with dizocilpine, it showed a strong tendency to attenuate the dizocilpine-induced deficit. In the plus-maze, ifenprodil had an anxiolytic profile which was accompanied by an increase in locomotion. Dizocilpine had an anxiolytic profile in this model and increased locomotor activity. When co-administered with dizocilpine, ifenprodil reduced both the anxiolytic and locomotor effects of dizocilpine. When co-administered with ifenprodil, cyclopentyladenosine (CPA) and 1,3-dipropyl-8-cyclopentylxanthine (CPX) reduced the anxiolytic effect of ifenprodil. CPA and CPX in combination did not reverse the anxiolytic effect of ifenpropil. It is concluded that NMDA antagonists with different sites of action can show distinct behavioural profiles, with dizocilpine but not ifenprodil inducing a deficit in working memory, while both are anxiolytic. Blockade of NMDA receptors by ifenprodil, however, can preclude any response to dizocilpine. The anxiolytic activity of ifenprodil may involve the release of purines acting at adenosine receptors.

Transcriptome Analysis of Manganese-deficient Chlamydomonas reinhardtii Provides Insight on the Chlorophyll Biosynthesis Pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lockhart, Ainsley; Zvenigorodsky, Natasha; Pedraza, Mary Ann

2011-08-11

The biosynthesis of chlorophyll and other tetrapyrroles is a vital but poorly understood process. Recent genomic advances with the unicellular green algae Chlamydomonas reinhardtii have created opportunity to more closely examine the mechanisms of the chlorophyll biosynthesis pathway via transcriptome analysis. Manganese is a nutrient of interest for complex reactions because of its multiple stable oxidation states and role in molecular oxygen coordination. C. reinhardtii was cultured in Manganese-deplete Tris-acetate-phosphate (TAP) media for 24 hours and used to create cDNA libraries for sequencing using Illumina TruSeq technology. Transcriptome analysis provided intriguing insight on possible regulatory mechanisms in the pathway. Evidencemore » supports similarities of GTR (Glutamyl-tRNA synthase) to its Chlorella vulgaris homolog in terms of Mn requirements. Data was also suggestive of Mn-related compensatory up-regulation for pathway proteins CHLH1 (Manganese Chelatase), GUN4 (Magnesium chelatase activating protein), and POR1 (Light-dependent protochlorophyllide reductase). Intriguingly, data suggests possible reciprocal expression of oxygen dependent CPX1 (coproporphyrinogen III oxidase) and oxygen independent CPX2. Further analysis using RT-PCR could provide compelling evidence for several novel regulatory mechanisms in the chlorophyll biosynthesis pathway.« less

Effect of test exercises and mask donning on measured respirator fit.

PubMed

Crutchfield, C D; Fairbank, E O; Greenstein, S L

1999-12-01

Quantitative respirator fit test protocols are typically defined by a series of fit test exercises. A rationale for the protocols that have been developed is generally not available. There also is little information available that describes the effect or effectiveness of the fit test exercises currently specified in respiratory protection standards. This study was designed to assess the relative impact of fit test exercises and mask donning on respirator fit as measured by a controlled negative pressure and an ambient aerosol fit test system. Multiple donnings of two different sizes of identical respirator models by each of 14 test subjects showed that donning affects respirator fit to a greater degree than fit test exercises. Currently specified fit test protocols emphasize test exercises, and the determination of fit is based on a single mask donning. A rationale for a modified fit test protocol based on fewer, more targeted test exercises and multiple mask donnings is presented. The modified protocol identified inadequately fitting respirators as effectively as the currently specified Occupational Safety and Health Administration (OSHA) quantitative fit test protocol. The controlled negative pressure system measured significantly (p < 0.0001) more respirator leakage than the ambient aerosol fit test system. The bend over fit test exercise was found to be predictive of poor respirator fit by both fit test systems. For the better fitting respirators, only the talking exercise generated aerosol fit factors that were significantly lower (p < 0.0001) than corresponding donning fit factors.

Specificity of a Maximal Step Exercise Test

ERIC Educational Resources Information Center

Darby, Lynn A.; Marsh, Jennifer L.; Shewokis, Patricia A.; Pohlman, Roberta L.

2007-01-01

To adhere to the principle of "exercise specificity" exercise testing should be completed using the same physical activity that is performed during exercise training. The present study was designed to assess whether aerobic step exercisers have a greater maximal oxygen consumption (max VO sub 2) when tested using an activity specific, maximal step…

Upper Eocene Spherules at ODP Site 1090B

NASA Technical Reports Server (NTRS)

Liu, S.; Kyte, F. T.; Glass, B. P.; Gersonde, R.

2000-01-01

Our two labs independently discovered upper Eocene microtektites and microkrystites at ODP Site 1090, a new South Atlantic locality near the Agulhus Ridge. This is a significant new data point for the strewn fields of these spherules, which were recently extended into the Atlantic sector of the Southern Ocean when they were reported at ODP Site 689 on the Maude Rise. The microtektites have been regarded as related to North American tektites and the microkrystites as belonging to the clinopyroxene-bearing (cpx) spherule strewn field. Initial reports indicate that Site 1090 contains a complete sequence of upper Eocene sediments composed of diatom and nannofossil oozes. The magneto- and bio-stratigraphy indicate that impact-age sediments should occur in core 30X of Hole 1090B. One of us (FTK) took 2 cc samples at 10 cm intervals over 600 cm of core for Ir analyses and the senior author (SL) took 3 cc samples at 20 cm intervals to search for spherules. Both studies proved successful and additional samples were obtained to confirm initial results and better define the Ir anomaly and spherule abundances. Peak Ir concentrations of 0.97 ng/g were found at 1090B-30X-5, 105-106cm and 0.78 ng/g at 115-116 cm. Anomalous Ir concentrations (greater than 0.1 ng/g) extend over about 100 cm of core. Preliminary results indicate that the excess Ir at this site is about 25 ng per sq cm. About 380 microtektites (>63 pm) and 2492 microkrystites (>63 pm) were recovered over a 1.8 m interval with a peak abundance of microtektites (106/gram) and microkrystites (562/gram) at 1090B-30X- 5, 114-115 cm. The largest microtektite is approximately 960 x 1140 micron in size. About 55 % are spherical, and the rest are disc, cylinder, dumbbell, teardrop, or fragments. Most of the microtektites are transparent colorless, but a few are transparent pale brown or green. Preliminary data indicate that the microtektites at Site 1090 have similar major oxide compositions to those at Site 689. About 50% of the cpx spherules are spherical, the rest are fragments. They range from yellowish translucent to dark opaque. Based on stratigraphic data, occurrence of a positive Ir anomaly, and similar appearance and major oxide compositions of the Site 1090 spherules to those at Site 689, we believe that the spherule layer(s) are the same at both sites. However, there are significant differences between these two sites. At Site 689 the peak abundance of the cpx spherules is slightly below that of the microtektites. We can distinguish no such separation at Site 1090, despite a somewhat higher sediment accumulation rates. Peak Ir concentrations are about four times higher at Site 1090, resulting in a similarly higher total flux of Ir for this site compared to Site 689 on the Maude Rise. This is generally consistent with the flux of cpx spherules (greater than 63 pm) which is estimated to be approximately -2100 per sq cm, about twice that of Site 689D (1040 sq cm) and with the cpx-spherule component being a principal carrier of the Ir signal. The number of microtektites per sq cm (greater than 63 micron) is nearly the same at both sites, approximately 300 in 1090B and 280 in 689B. A decrease in the greater than 63 micron size fraction (consisting primarily of diatoms and radiolaria) is coincident with the spherule layer at both sites suggesting that the impact(s) that produced the spherule layer(s) may have had an adverse affect on the marine plankton.

Oceanization of the lithospheric mantle: the study case of the spinel peridotites from Monte Maggiore (Corsica, France).

NASA Astrophysics Data System (ADS)

Piccardo, G. B.

2009-04-01

The Monte Maggiore peridotite body, cropping out within the Alpine Corsica metamorphic belt, is an ophiolite massif derived from the more internal setting of the Jurassic Ligurian Tethys basin. It is mostly composed by spinel and plagioclase peridotites that are cut by MORB gabbroic dykes. The spinel peridotites, similarly to other ophiolitic peridotites from the Internal Ligurides, have been considered, on the basis of their low abundance of fusible components, low Si and high Mg contents, as refractory residua after MORB-type partial melting related to the formation of the Jurassic basin (e.g. Rampone et al., 1997). Recent studies (e.g. Müntener & Piccardo 2003; Rampone et al. 2008) have evidenced that these depleted spinel peridotites show diffuse melt-rock interaction micro-textures and contrasting bulk vs. mineral chemistry features which cannot be simply reconciled with partial melting. Accordingly, these peridotites have been recognized as reactive peridotites, formed by interaction of pristine peridotites with melts percolating by porous flow. Geochemical data have evidenced the depleted MORB signature of the percolating melts. Recent field studies at Monte Maggiore (Piccardo, 2007; Piccardo & Guarnieri, 2009), have revealed: 1) the presence and local abundance of pyroxenite-bearing, cpx-rich spinel lherzolites and 2) the replacement relationships of the reactive peridotites on the pyroxenite-bearing lherzolite rock-types. The pyroxenite-veined spinel lherzolites record a composite history of subsolidus evolution under lithospheric P-T conditions, thus indicating their provenance from the sub-continental lithospheric mantle. Accordingly, the pristine sub-continental mantle protoliths were infiltrated by MORB melts and transformed by melt-rock interaction to reactive spinel peridotites and refertilized by melt impregnation to plagioclase-enriched peridotites. Available isotopic data on the Mt. Maggiore spinel and plagioclase peridotites and gabbroic rocks (Rampone, 2004; Rampone et al., 2008; 2009) provide reliable geochronological informations (i.e. Sm-Nd cpx-plg-wr isochron ages and Sm-Nd model ages) and evidence that the whole mafic and ultramafic rocks show an overall Sm/Nd isotopic homogeneity. Cpx-plg-wr data from gabbroic dykes define internal isochrones yielding Jurassic ages (162+/-10 Ma and 159+/-15 Ma, respectively). The plg-cpx(-wr) isochrons for impregnated plagioclase peridotites yields age of 155+/-6 Ma. The initial ɛNd values (8.9-9.7) are indicative of a MORB affinity. Calculated DM model ages for both spinel and plagioclase peridotites point to a Late Jurassic age (150 Ma). Isotope ratios of cpx from spinel and plagioclase peridotites conform to the linear array defined by overall gabbroic rocks. The isotopic evidence from the melt-percolated, reactive and impregnated peridotites indicates that the pristine lithospheric mantle protoliths were isotopically homogenized by the melt-rock interaction during percolation/impregnation processes which erased any pre-existing isotopic signature. Moreover, the overall Sm/Nd isotopic homogeneity indicates that the asthenospheric mantle sources of the infiltrating melts were isotopically homogeneous. Accordingly, it is plausible that percolation and intrusion were operated by similar and coeval Late Jurassic MORB-type melts. In conclusion, petrologic and isotopic data allow to recognize that the extending sub-continental lithospheric mantle was infiltrated by Late Jurassic MORB melts, formed by asthenospheric decompression-induced partial melting during continental extension and rifting. Melt-peridotite interaction modified the compositional features of the lithospheric mantle and caused its isotopic resetting. Accordingly, the sub-continental lithospheric mantle underwent an "oceanization" process (i.e. isotope resetting to "oceanic" MORB signatures) during Late Jurassic times operated by asthenospheric MORB melts. Depending on the melt composition, the lithospheric level and the mode of melt-rock interaction, fertile peridotites from the sub-continental lithospheric mantle were transformed, concomitantly, to depleted spinel peridotites and refertilized plagioclase peridotites.

Benefits of exercise training and the correlation between aerobic capacity and functional outcomes and quality of life in elderly patients with coronary artery disease.

PubMed

Chen, Chia-Hsin; Chen, Yi-Jen; Tu, Hung-Pin; Huang, Mao-Hsiung; Jhong, Jing-Hui; Lin, Ko-Long

2014-10-01

Cardiopulmonary exercise training is beneficial to people with coronary artery disease (CAD). Nevertheless, the correlation between aerobic capacity, and functional mobility and quality of life in elderly CAD patients is less addressed. The purpose of the current study is to investigate the beneficial effects of exercise training in elderly people with CAD, integrating exercise stress testing, functional mobility, handgrip strength, and health-related quality of life. Elderly people with CAD were enrolled from the outpatient clinic of a cardiac rehabilitation unit in a medical center. Participants were assigned to the exercise training group (N = 21) or the usual care group (N = 15). A total of 36 sessions of exercise training, completed in 12 weeks, was prescribed. Echocardiography, exercise stress testing, the 6-minute walking test, Timed Up and Go test, and handgrip strength testing were performed, and the Short-Form 36 questionnaire (SF-36) was administered at baseline and at 12-week follow-up. Peak oxygen consumption improved significantly after training. The heart rate recovery improved from 13.90/minute to 16.62/minute after exercise training. Functional mobility and handgrip strength also improved after training. Significant improvements were found in SF-36 physical function, social function, role limitation due to emotional problems, and mental health domains. A significant correlation between dynamic cardiopulmonary exercise testing parameters, the 6-minute walking test, Timed Up and Go test, handgrip strength, and SF-36 physical function and general health domains was also detected. Twelve-week, 36-session exercise training, including moderate-intensity cardiopulmonary exercise training, strengthening exercise, and balance training, is beneficial to elderly patients with CAD, and cardiopulmonary exercise testing parameters correlate well with balance and quality of life. Copyright © 2014. Published by Elsevier Taiwan.

Combined exercise is more effective than aerobic exercise in the improvement of fall risk factors: a randomized controlled trial in community-dwelling older men.

PubMed

Sousa, Nelson; Mendes, Romeu; Silva, André; Oliveira, José

2017-04-01

To compare the long-term effects of two community-based exercise programs on fall risk factors, such as balance, postural control, mobility and leg strength, in community-dwelling older men. Single-blinded randomized controlled trial, comparing three groups, with follow-ups at eight, 16, 24 and 32 weeks. Older men independent-living residing in Maia city, Portugal. A total of 66 older men (aged 69.0 ±4.9 years) were randomly assigned to an aerobic exercise group ( n = 22), a combined aerobic and resistance exercise group ( n = 22) or a control group ( n = 22). Both community-based exercise programs consisted of three sessions each week for 32 consecutive weeks and were planned for moderate-to-vigorous intensity. The control group had no exercise intervention. Main outcomes were measured by the Timed Up and Go Test, functional reach test, 30-second chair stand test and 6-minute walk test, on five different occasions. Repeated measures of analysis of covariance revealed significant main effects between time × group interaction in all outcomes over time (Timed Up and Go Test: p < 0.001; functional reach test: p = 0.002; 30-second chair stand: p = 0.001; 6-minute walk test: p < 0.001). Both exercise groups reported improvements; however, better performance was identified in the combined aerobic and resistance exercise group compared with the aerobic exercise group (-20.3% vs. -9.1% on the Timed Up and Go Test, +27.5% vs. +10.9% on the functional reach test, +20.8% vs. +7.3% on 30-second chair stand, +10.9% vs. +3.5% on 6-minute walk test). Adding resistance exercise to aerobic exercise improves factors associated with an increased risk of falls. However, both exercise regimes, combined or aerobic alone, are more effective than no exercise in the reduction of fall risk factors. ClinicalTrials.org #NCT01874132.

Nature of the lithospheric mantle beneath the Arabian Shield and genesis of Al-spinel micropods: Evidence from the mantle xenoliths of Harrat Kishb, Western Saudi Arabia

NASA Astrophysics Data System (ADS)

Ahmed, Ahmed H.; Moghazi, Abdel Kader M.; Moufti, Mohamed R.; Dawood, Yehia H.; Ali, Kamal A.

2016-01-01

The Harrat Kishb area of western Saudi Arabia is part of the Cenozoic volcanic fields in the western margin of the Arabian Shield. Numerous fresh ultramafic xenoliths are entrained in the basanite lava of Harrat Kishb, providing an opportunity to study the nature and petrogenetic processes involved in the evolution of the lithospheric mantle beneath the Arabian Shield. Based on the petrological characteristics and mineralogical compositions, the majority of the mantle xenoliths ( 92%) are peridotites (lherzolites and pyroxene-bearing harzburgites); the remaining xenoliths ( 8%) are unusual spinel-rich wehrlites containing black Al-spinel micropods. The two types of mantle xenoliths display magmatic protogranular texture. The peridotite xenoliths have high bulk-rock Mg#, high forsterite (Fo90-Fo92) and NiO (0.24-0.46 wt.%) contents of olivine, high clinopyroxene Mg# (0.91-0.93), variable spinel Cr# (0.10-0.49, atomic ratio), and approximately flat chondrite-normalized REE patterns. These features indicate that the peridotite xenoliths represent residues after variable degrees of melt extraction from fertile mantle. The estimated P (9-16 kbar) and T (877-1227 °C) as well as the oxidation state (ΔlogfO2 = - 3.38 to - 0.22) under which these peridotite xenoliths originated are consistent with formation conditions similar to most sub-arc abyssal-type peridotites worldwide. The spinel-rich wehrlite xenoliths have an unusual amount ( 30 vol.%) of Al-spinel as peculiar micropods with very minor Cr2O3 content (< 1 wt.%). Olivines of the spinel-rich wehrlites have low-average Fo (Fo81) and NiO (0.18 wt.%) contents, low-average cpx Mg# (0.79), high average cpx Al2O3 content (8.46 wt.%), and very low-average spinel Cr# (0.01). These features characterize early mantle cumulates from a picritic melt fraction produced by low degrees of partial melting of a garnet-bearing mantle source. The relatively high Na2O and Al2O3 contents of cpx suggest that the spinel-rich wehrlites are formed under high P (11-14 kbar), T (1090-1130 °C), and oxidation state (ΔlogfO2 FMQ = + 0.14 to + 0.37), which occurred slightly below the crust-mantle boundary. The REE patterns of spinel-rich wehrlites are almost similar to those of the associated peridotite xenoliths, which confirm at least a spatial genetic linkage between them. Regarding the formation of Al-spinel micropods in spinel-rich wehrlite cumulates, it is suggested that the melt-rock reaction mechanism is not the only process by which podiform chromitite is formed. Early fractionation of picritic melts produced by partial melting of a mantle source under high P-T conditions could be another mechanism. The cpx composition, not opx, as it was assumed, seems to be the main control of the size and composition of spinel concentrations.

Effect of nutritional composition of meals on exercise tests in patients with ischaemic heart disease.

PubMed

Blondheim, David S; Yosef, Avigail; Marmor, Alon T

2004-12-01

Patients with ischaemic heart disease have to perform exercise tests repeatedly. It is not clear if a small meal eaten before the test might influence it and if the meal's composition is important. We performed a double blind, randomised, crossover study on 20 volunteers with documented ischaemic heart disease known to have positive exercise tests. Each had three symptom limited exercise tests done one hour after a 200 ml meal, rich in either fat, carbohydrate or protein. Each postprandial test was compared to a fasting exercise test performed just before the meal. Postprandial blood pressure, time to angina and to peak exercise and double product at onset of ST-depression were not significantly altered by any of the meals. Heart rate was slightly increased only after the fat meal. The nutritional composition of a small meal eaten an hour before an exercise test has no clinically important impact on the results of the test in patients with stable angina pectoris.

Exercise blood pressure and the risk of future hypertension.

PubMed

Holmqvist, L; Mortensen, L; Kanckos, C; Ljungman, C; Mehlig, K; Manhem, K

2012-12-01

The aim of this prospective cohort study was to identify which blood pressure measurement during exercise is the best predictor of future hypertension. Further we aimed to create a risk chart to facilitate the evaluation of blood pressure reaction during exercise testing. A number (n=1047) of exercise tests by bicycle ergometry, performed in 1996 and 1997 were analysed. In 2007-2008, 606 patients without hypertension at the time of the exercise test were sent a questionnaire aimed to identify current hypertension. The response rate was 58% (n=352). During the 10-12 years between exercise test and questionnaire, 23% developed hypertension. The strongest predictors of future hypertension were systolic blood pressure (SBP) before exercise (odds ratios (OR) 1.63 (1.31-2.01) for 10 mm Hg difference) in combination with the increase of SBP over time during exercise testing (OR 1.12 (1.01-1.24) steeper increase for every 1 mm Hg min(-1)). A high SBP before exercise and a steep rise in SBP over time represented a higher risk of developing hypertension. A risk chart based on SBP before exercise, increase of SBP over time and body mass index was created. SBP before exercise, maximal SBP during exercise and SBP at 100 W were significant single predictors of future hypertension and the prediction by maximal SBP was improved by adjusting for time/power at which SBP max was reached during exercise testing. Recovery ratio (maximal SBP/SBP 4 min after exercise) was not predictive of future hypertension.

Graded Aerobic Treadmill Testing in Adolescent Traumatic Brain Injury Patients.

PubMed

Cordingley, Dean M; Girardin, Richard; Morissette, Marc P; Reimer, Karen; Leiter, Jeff; Russell, Kelly; Ellis, Michael J

2017-11-01

To examine the safety and tolerability of clinical graded aerobic treadmill testing in recovering adolescent moderate and severe traumatic brain injury (TBI) patients referred to a multidisciplinary pediatric concussion program. We completed a retrospective case series of two moderate and five severe TBI patients (mean age, 17.3 years) who underwent initial Buffalo Concussion Treadmill Testing at a mean time of 71.6 days (range, 55-87) postinjury. Six patients completed one graded aerobic treadmill test each and one patient underwent initial and repeat testing. There were no complications. Five initial treadmill tests were completely tolerated and allowed an accurate assessment of exercise tolerance. Two initial tests were terminated early by the treatment team because of neurological and cardiorespiratory limitations. As a result of testing, two patients were cleared for aerobic exercise as tolerated and four patients were treated with individually tailored submaximal aerobic exercise programs resulting in subjective improvement in residual symptoms and/or exercise tolerance. Repeat treadmill testing in one patient performed after 1 month of treatment with submaximal aerobic exercise prescription was suggestive of improved exercise tolerance. One patient was able to tolerate aerobic exercise following surgery for posterior glottic stenosis. Preliminary results suggest that graded aerobic treadmill testing is a safe, well tolerated, and clinically useful tool to assess exercise tolerance in appropriately selected adolescent patients with TBI. Future prospective studies are needed to evaluate the effect of tailored submaximal aerobic exercise prescription on exercise tolerance and patient outcomes in recovering adolescent moderate and severe TBI patients.

A Cross-Sectional Study of the Prevalence of Exercise-Induced Hypertension in Childhood Following Repair of Coarctation of the Aorta.

PubMed

Luitingh, Taryn L; Lee, Melissa G Y; Jones, Bryn; Kowalski, Remi; Weskamp Aguero, Sofia; Koleff, Jane; Zannino, Diana; Cheung, Michael M H; d'Udekem, Yves

2018-03-27

Exercise-testing may be a more tolerable method of detecting hypertension in children after coarctation repair compared to gold-standard 24-hour ambulatory blood pressure (BP) monitoring (ABPM). This study aims to determine the prevalence of exercise-induced hypertension and end-organ damage in children after coarctation repair, and the effectiveness of exercise-testing compared to 24-hour ABPM in this population. Exercise-testing (Bruce protocol), transthoracic echocardiogram, 24-hour ABPM, and pulse wave velocity were performed in 41 patients aged 8 to 18 years with previous coarctation repair. Median age at repair was 13 days. Exercise-testing data were compared to healthy paediatric controls. Hypertension was defined as BP >95th percentile on 24-hour ABPM compared to normalised data, and systolic BP (SBP) arbitrarily >200mmHg on exercise-testing. After 13±3years, 39% (14/36) were hypertensive on 24-hour ABPM and 12% (5/41) on exercise-testing. Coarctation patients had a higher peak exercise SBP and reduced endurance compared to controls (164±26mmHg vs. 148±19mmHg, p=0.003; and 13.0±1.7mins vs. 14.2±2.4mins, p=0.007; respectively). All patients with a peak exercise SBP >190mmHg were hypertensive on 24-hour ABPM. Pulse wave velocity was higher in hypertensive patients on exercise-testing and 24-hour ABPM compared to normotensive patients (p=0.004 and p=0.06; respectively). Exercise-testing may be a useful tool to detect hypertension in children and young adults after coarctation repair, particularly in those who do not tolerate 24-hour ABPM. Normative peak exercise BP data for age should be obtained to improve the accuracy of exercise-testing in detecting hypertension. Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Combination of ciclopirox olamine and sphingosine-1-phosphate as granulation enhancer in diabetic wounds.

PubMed

Lim, Natalie Sheng Jie; Sham, Adeline; Chee, Stella Min Ling; Chan, Casey; Raghunath, Michael

2016-09-01

Granulation tissue formation requires a robust angiogenic response. As granulation tissue develops, collagen fibers are deposited and compacted. Forces generated in the wake of this process drive wound contraction to reduce the wound area. In diabetics, both angiogenesis and wound contraction are diminished leading to impaired wound healing. To emulate this pathology and to address it pharmacologically, we developed a wound healing model in the diabetic Zucker fatty rat and tested a topical proangiogenic strategy combining antifungal agent ciclopirox olamine (CPX) and lysophospholipid sphingosine-1-phosphate (S1P) to promote diabetic wound closure. In vitro, we demonstrated that CPX + S1P up-regulates a crucial driver of angiogenesis, hypoxia-inducible factor-1, in endothelial cells. Injection of CPX + S1P into subcutaneously implanted sponges in experimental rats showed, in an additive manner, a fivefold increased endothelial infiltration and lectin-perfused vessel length. We developed a splinted diabetic rodent model to achieve low wound contraction rates that are characteristic for the healing mode of diabetic ulcers in humans. We discovered specific dorsal sites that allowed for incremental full-thickness excisional wound depths from 1 mm (superficial) to 3 mm (deep). This enabled us to bring down wound contraction from 51% in superficial wounds to 8% in deep wounds. While the effects of topical gel treatment of CPX + S1P were masked by the rodent-characteristic dominant contraction in superficial wounds, they became clearly evident in deep diabetic wounds. Here, a fivefold increase of functional large vessels resulted in accelerated granulation tissue formulation, accompanied by a 40% increase of compacted thick collagen fibers. This was associated with substantially reduced matrix metalloproteinase-3 and -13 expression. These findings translated into a fivefold increase in granulation-driven contraction, promoting diabetic wound closure. With CPX and S1P analogues already in clinical use, their combination presents itself as an attractive proangiogenic treatment to be repurposed for diabetic wound healing. © 2016 by the Wound Healing Society.

Predictive Accuracy of Exercise Stress Testing the Healthy Adult.

ERIC Educational Resources Information Center

Lamont, Linda S.

1981-01-01

Exercise stress testing provides information on the aerobic capacity, heart rate, and blood pressure responses to graded exercises of a healthy adult. The reliability of exercise tests as a diagnostic procedure is discussed in relation to sensitivity and specificity and predictive accuracy. (JN)

Phylogenetic analysis of HIV-1 reverse transcriptase sequences from 382 patients recruited in JJ Hospital of Mumbai, India, between 2002 and 2008.

PubMed

Deshpande, Alaka; Jauvin, Valerie; Pinson, Patricia; Jeannot, Anne Cecile; Fleury, Herve J

2009-06-01

Analysis of reverse transcriptase (RT) sequences of 382 HIV-1 isolates from untreated and treated patients recruited in JJ Hospital (Mumbai, India) between 2002 and 2008 shows that subtype C is largely predominant (98%) and that non-C sequences cluster with A1, B, CRF01_AE, and CRF06_cpx.

Mg-Fe Isotope Systems of Mantle Xenoliths: Constrains on the Evolution of Siberian Craton

NASA Astrophysics Data System (ADS)

An, Y.; Kiseeva, E. S.; Sobolev, N. V.; Zhang, Z.

2017-12-01

Mantle xenoliths bring to the surface a variety of lithologies (dunites, lherzolites, harzburgites, wehrlites, eclogites, pyroxenites, and websterites) and represent snapshots of the geochemical processes that occur deep within the Earth. Recent improvements in the precision of the MC-ICP-MS measurements have allowed us to expand the amount of data on Mg and Fe isotopes for mantle-derived samples. For instance, to constrain the isotopic composition of the Earth based on the study of spinel and garnet peridotites (An et al., 2017; Teng et al., 2010), to trace the origin and to investigate the isotopic fractionation mechanism during metamorphic process using cratonic or orogenic eclogites (Li et al., 2011; Wang et al., 2012) and to reveal the metasomatism-induced mantle heterogeneity by pyroxenites (Hu et al., 2016). Numerous multi-stage modification events and mantle layering are detected in the subcontinental lithospheric mantle under the Siberian craton (Ashchepkov et al., 2008a; Sobolev et al., 1975, etc). Combined analyses of Mg and Fe isotopic systems could provide new constraints on the formation and evolution of the ancient cratonic mantle. In order to better constrain the magnitude and mechanism of inter-mineral Mg and Fe isotopic fractionations at high temperatures, systematic studies of mantle xenoliths are needed. For example, theoretical calculations and natural samples measurements have shown that large equilibrium Mg isotope fractionations controlled by the difference in coordination number of Mg among minerals could exist (Huang et al., 2013; Li et al., 2011). Thus, the Mg isotope geothermometer could help us trace the evolution history of ancient cratons. In this study we present Mg and Fe isotopic data for whole rocks and separated minerals (clinopyroxene (cpx) and garnet (grt)) from different types of mantle xenoliths (garnet pyroxenites, eclogites, grospydites and garnet peridotites) from a number of kimberlite pipes in Siberian craton (Udachnaya, Obnazhennaya, Mir, and Zagadochnaya). The large Mg and Fe isotope fractionations between clinopyroxene and garnet for various mantle rocks (Δ26Mg cpx-gnt= 0.360‰ 0.888‰, Δ56Fe cpx-gnt= 0.018‰ 0.348‰) indicate that the Siberian cratonic lithosphetic mantle has undergone multiple complex metasomatic and re-equilibration events.

Garnet Pyroxenites from Kaula, Hawaii: Implications for Plume-Lithosphere Interaction

NASA Astrophysics Data System (ADS)

Bizimis, M.; Garcia, M. O.; Norman, M. D.

2006-12-01

The presence of garnet pyroxenite xenoliths on Oahu and Kaula Islands, Hawaii, provides the rare opportunity to investigate the composition of the deeper oceanic mantle lithosphere and the nature of plume-lithosphere interaction in two dimensions, downstream from the center of the Hawaiian plume. Kaula (60 miles SW of Kauai) is on the same bathymetric shallow as Kauai and the Kaula-Niihau-Kauai islands form a cross-trend relationship to the Hawaiian Island ridge. Here, we present the first Sr-Nd isotope data on clinopyroxenes (cpx) from Kaula pyroxenites, and we compare them with the Salt Lake Crater (SLC) pyroxenites from Oahu. The Kaula cpx major element compositions overlap those of the (more variable) SLC pyroxenites (e.g. Mg# = 0.79-0.83), except for their higher Al2O3 contents (9% vs. 5-8%) than the SLC. The Kaula cpx are LREE enriched with elevated Dy/Yb ratios, similar to the SLC pyroxenites and characteristic of the presence of garnet that preferentially incorporates the HREE. In Sr-Nd isotope space, the Kaula pyroxenite compositions (87Sr/86Sr= 0.70312-0.70326, ɛNd= 7.2-8.6) overlap those of both the Oahu-Kauai post erosional lavas and the SLC pyroxenites, falling at the isotopically depleted end of the Hawaiian lava compositions. The depleted Sr-Nd isotope compositions of the Kaula pyroxenites suggest that they are not related to the isotopically enriched shield stage Hawaiian lavas, either as a source material (i.e. recycled eclogite) or as cumulates. Their elevated 87Sr/86Sr ratios relative to MORB also suggests that they are not likely MORB-related cumulates. The similarities between the Oahu and Kaula pyroxenites, some 200 km apart, suggest the widespread presence of pyroxenitic material in the deeper (>60km) Pacific lithosphere between Oahu and Kaula-Kauai, as high pressure cumulates from melts isotopically similar to the secondary Hawaiian volcanism. The presence of this material within the lower lithosphere is consistent with seismic observations suggesting erosion and replacement of the deeper Pacific lithosphere by plume material, downstream from the center of the plume.

Blood flow patterns during incremental and steady-state aerobic exercise.

PubMed

Coovert, Daniel; Evans, LeVisa D; Jarrett, Steven; Lima, Carla; Lima, Natalia; Gurovich, Alvaro N

2017-05-30

Endothelial shear stress (ESS) is a physiological stimulus for vascular homeostasis, highly dependent on blood flow patterns. Exercise-induced ESS might be beneficial on vascular health. However, it is unclear what type of ESS aerobic exercise (AX) produces. The aims of this study are to characterize exercise-induced blood flow patterns during incremental and steady-state AX. We expect blood flow pattern during exercise will be intensity-dependent and bidirectional. Six college-aged students (2 males and 4 females) were recruited to perform 2 exercise tests on cycleergometer. First, an 8-12-min incremental test (Test 1) where oxygen uptake (VO2), heart rate (HR), blood pressure (BP), and blood lactate (La) were measured at rest and after each 2-min step. Then, at least 48-hr. after the first test, a 3-step steady state exercise test (Test 2) was performed measuring VO2, HR, BP, and La. The three steps were performed at the following exercise intensities according to La: 0-2 mmol/L, 2-4 mmol/L, and 4-6 mmol/L. During both tests, blood flow patterns were determined by high-definition ultrasound and Doppler on the brachial artery. These measurements allowed to determine blood flow velocities and directions during exercise. On Test 1 VO2, HR, BP, La, and antegrade blood flow velocity significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). Retrograde blood flow velocity did not significantly change during Test 1. On Test 2 all the previous variables significantly increased in an intensity-dependent manner (repeated measures ANOVA, p<0.05). These results support the hypothesis that exercise induced ESS might be increased in an intensity-dependent way and blood flow patterns during incremental and steady-state exercises include both antegrade and retrograde blood flows.

Exercise-Induced Hypoalgesia After Isometric Wall Squat Exercise: A Test-Retest Reliabilty Study.

PubMed

Vaegter, Henrik Bjarke; Lyng, Kristian Damgaard; Yttereng, Fredrik Wannebo; Christensen, Mads Holst; Sørensen, Mathias Brandhøj; Graven-Nielsen, Thomas

2018-05-19

Isometric exercises decrease pressure pain sensitivity in exercising and nonexercising muscles known as exercise-induced hypoalgesia (EIH). No studies have assessed the test-retest reliability of EIH after isometric exercise. This study investigated the EIH on pressure pain thresholds (PPTs) after an isometric wall squat exercise. The relative and absolute test-retest reliability of the PPT as a test stimulus and the EIH response in exercising and nonexercising muscles were calculated. In two identical sessions, PPTs of the thigh and shoulder were assessed before and after three minutes of quiet rest and three minutes of wall squat exercise, respectively, in 35 healthy subjects. The relative test-retest reliability of PPT and EIH was determined using analysis of variance models, Person's r, and intraclass correlations (ICCs). The absolute test-retest reliability of EIH was determined based on PPT standard error of measurements and Cohen's kappa for agreement between sessions. Squat increased PPTs of exercising and nonexercising muscles by 16.8% ± 16.9% and 6.7% ± 12.9%, respectively (P < 0.001), with no significant differences between sessions. PPTs within and between sessions showed moderately strong correlations (r ≥ 0.74) and excellent (ICC ≥ 0.84) within-session (rest) and between-session test-retest reliability. EIH responses of exercising and nonexercising muscles showed no systematic errors between sessions; however, the relative test-retest reliability was low (ICCs = 0.03-0.43), and agreement in EIH responders and nonresponders between sessions was not significant (κ < 0.13, P > 0.43). A wall squat exercise increased PPTs compared with quiet rest; however, the relative and absolute reliability of the EIH response was poor. Future research is warranted to investigate the reliability of EIH in clinical pain populations.

Abdominal symptoms during physical exercise and the role of gastrointestinal ischaemia: a study in 12 symptomatic athletes.

PubMed

ter Steege, Rinze W F; Geelkerken, Robert H; Huisman, Ad B; Kolkman, Jeroen J

2012-10-01

Gastrointestinal (GI) symptoms during exercise may be caused by GI ischaemia. The authors report their experience with the diagnostic protocol and management of athletes with symptomatic exercise-induced GI ischaemia. The value of prolonged exercise tonometry in the diagnostic protocol of these patients was evaluated. Patients referred for GI symptoms during physical exercise underwent a standardised diagnostic protocol, including prolonged exercise tonometry. Indicators of GI ischaemia, as measured by tonometry, were related to the presence of symptoms during the exercise test (S+ and S- tests) and exercise intensity. 12 athletes were specifically referred for GI symptoms during exercise (five males and seven females; median age 29 years (range 15-46 years)). Type of sport was cycling, long-distance running and triathlon. Median duration of symptoms was 32 months (range 7-240 months). Splanchnic artery stenosis was found in one athlete. GI ischaemia was found in six athletes during submaximal exercise. All athletes had gastric and jejunal ischaemia during maximum intensity exercise. No significant difference was found in gastric and jejunal Pco(2) or gradients between S+ and S- tests during any phase of the exercise protocol. In S+ tests, but not in S- tests, a significant correlation between lactate and gastric gradient was found. In S+ tests, the regression coefficients of gradients were higher than those in S- tests. Treatment advice aimed at limiting GI ischaemia were successful in reducing complaints in the majority of the athletes. GI ischaemia was present in all athletes during maximum intensity exercise and in 50% during submaximal exercise. Athletes with GI symptoms had higher gastric gradients per mmol/l increase in lactate, suggesting an increased susceptibility for the development of ischaemia during exercise. Treatment advice aimed at limiting GI ischaemia helped the majority of the referred athletes to reduce their complaints. Our results suggest an important role for GI ischaemia in the pathophysiology of their complaints.

Utilization of the graded universal testing system to increase the efficiency for assessing aerobic and anaerobic capacity

NASA Technical Reports Server (NTRS)

Rodgers, Sandra L.

1992-01-01

The in-flight exercise test performed by cosmonauts as part of the Russian Exercise Countermeasure Program is limited to 5 minutes due to communication restrictions. During a recent graded exercise test on a U.S. Shuttle flight, the test was terminated early due to an upcoming loss of signal (LOS) with the ground. This exercise test was a traditional test where the subject's exercise capacity dictates the length of the test. For example, one crew member may take 15 minutes to complete the test, while another may take 18 minutes. The traditional exercise test limits the flight schedulers to large blocks of space flight time in order to provide medical and research personnel information on the fitness capacity (maximal oxygen uptake: VO2max) of crew members during flight. A graded exercise test that would take a finite amount of time and a set preparation and recovery time would ease this problem by allowing flight schedulers to plan exercise tests in advance of LOS. The Graded Universal Testing System (GUTS) was designed to meet this goal. Fitness testing of astronauts before and after flight provides pertinent data on many variables. The Detailed Supplemental Objective (DSO608) protocol (6) is one of the graded exercise tests (GXT) currently used in astronaut testing before and after flight. Test times for this protocol have lasted from 11 to 18 minutes. Anaerobic capacity is an important variable that is currently not being evaluated before and after flight. Recent reports (1,2,5) from the literature have suggested that the oxygen deficit at supramaximal exercise is a measure of anaerobic capacity. We postulated that the oxygen deficit at maximal exercise would be an indication of anaerobic capacity. If this postulate can be accepted, then the efficiency of acquiring data from a graded exercise test would increase at least twofold. To examine this hypothesis anaerobic capacity was measured using a modified treadmill test (3,4) designed to exhaust the anaerobic systems in approximately 45 to 75 seconds. Lactate concentration in the blood was analyzed after all tests, since lactate is the end-product of anaerobic energy production. Therefore, the peak lactate response is an additional indication of anaerobic capacity. A preliminary comparison of the GUTS and the DSO608 suggests that the GUTS protocol would increase the efficiency of VO2max testing of astronauts before and after flight. Results for anaerobic capacity have not been tabulated.

The effects of water-based exercise in combination with blood flow restriction on strength and functional capacity in post-menopausal women.

PubMed

Araújo, Joamira P; Neto, Gabriel R; Loenneke, Jeremy P; Bemben, Michael G; Laurentino, Gilberto C; Batista, Gilmário; Silva, Júlio C G; Freitas, Eduardo D S; Sousa, Maria S C

2015-12-01

Water-based exercise and low-intensity exercise in combination with blood flow restriction (BFR) are two methods that have independently been shown to improve muscle strength in those of advancing age. The objective of this study was to assess the long-term effect of water-based exercise in combination with BFR on maximum dynamic strength and functional capacity in post-menopausal women. Twenty-eight women underwent an 8-week water-based exercise program. The participants were randomly allocated to one of the three groups: (a) water exercise only, (b) water exercise + BFR, or (c) a non-exercise control group. Functional capacity (chair stand test, timed up and go test, gait speed, and dynamic balance) and strength testing were tested before and after the 8-week aquatic exercise program. The main findings were as follows: (1) water-based exercise in combination with BFR significantly increased the lower limb maximum strength which was not observed with water-based exercise alone and (2) water-based exercise, regardless of the application of BFR, increased functional performance measured by the timed up and go test over a control group. Although we used a healthy population in the current study, these findings may have important implications for those who may be contraindicated to using traditional resistance exercise. Future research should explore this promising modality in these clinical populations.

Cardiopulmonary Response to Exercise Testing in People with Chronic Stroke: A Retrospective Study

PubMed Central

Billinger, Sandra A.; Taylor, Jordan M.; Quaney, Barbara M.

2012-01-01

Background and Purpose. This study investigated the cardiopulmonary response and safety of exercise testing at peak effort in people during the chronic stage of stroke recovery. Methods. This retrospective study examined data from 62 individuals with chronic stroke (males: 32; mean (SD); age: (12.0) yr) participating in an exercise test. Results. Both males and females had low cardiorespiratory fitness levels. No significant differences were found between gender for peak HR (P = 0.27), or VO2 peak (P = 0.29). Males demonstrated higher values for minute ventilation, tidal volume, and respiratory exchange ratio. No major adverse events were observed in the exercise tests conducted. Discussion and Conclusion. There are differences between gender that may play a role in exercise testing performance and should be considered when developing exercise programs. The low VO2 peak of this cohort of chronic stroke survivors suggests the need for participation in exercise interventions. PMID:21961083

Effects of humoral factors on ventilation kinetics during recovery after impulse-like exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C; Yunoki, T; Yano, Tokuo

2012-06-01

To clarify the ventilatory kinetics during recovery after impulse-like exercise, subjects performed one impulse-like exercise test (one-impulse) and a five-times repeated impulse-like exercises test (five-impulse). Duration and intensity of the impulse-like exercise were 20 sec and 400 watts (80 rpm), respectively. Although blood pH during recovery (until 10 min) was significantly lower in the five-impulse test than in the one-impulse test, ventilation (.VE) in the two tests was similar except during the first 30 sec of recovery, in which it was higher in the five-impulse test. In one-impulse, blood CO2 pressure (PCO2) was significantly increased at 1 min during recovery and then returned to the pre-exercise level at 5 min during recovery. In the five-impulse test, PCO2 at 1 min during recovery was similar to the pre-exercise level, and then it decreased to a level lower than the pre-exercise level at 5 min during recovery. Accordingly, PCO2 during recovery (until 30 min) was significantly lower in the five-impulse than in one-impulse test..VE and pH during recovery showed a curvilinear relationship, and at the same pH, ventilation was higher in the one-impulse test. These results suggest that ventilatory kinetics during recovery after impulse-like exercise is attributed partly to pH, but the stimulatory effect of lower pH is diminished by the inhibitory effect of lower PCO2.

One-minute heart rate recovery after cycloergometer exercise testing as a predictor of mortality in a large cohort of exercise test candidates: substantial differences with the treadmill-derived parameter.

PubMed

Gaibazzi, Nicola; Petrucci, Nicola; Ziacchi, Vigilio

2004-03-01

Previous work showed a strong inverse association between 1-min heart rate recovery (HRR) after exercising on a treadmill and all-cause mortality. The aim of this study was to determine whether the results could be replicated in a wide population of real-world exercise ECG candidates in our center, using a standard bicycle exercise test. Between 1991 and 1997, 1420 consecutive patients underwent ECG exercise testing performed according to our standard cycloergometer protocol. Three pre-specified cut-point values of 1-min HRR, derived from previous studies in the medical literature, were tested to see whether they could identify a higher-risk group for all-cause mortality; furthermore, we tested the possible association between 1-min HRR as a continuous variable and mortality using logistic regression. Both methods showed a lack of a statistically significant association between 1-min HRR and all-cause mortality. A weak trend toward an inverse association, although not statistically significant, could not be excluded. We could not validate the clear-cut results from some previous studies performed using the treadmill exercise test. The results in our study may only "not exclude" a mild inverse association between 1-min HRR measured after cycloergometer exercise testing and all-cause mortality. The 1-min HRR measured after cycloergometer exercise testing was not clinically useful as a prognostic marker.

Heritability, linkage, and genetic associations of exercise treadmill test responses.

PubMed

Ingelsson, Erik; Larson, Martin G; Vasan, Ramachandran S; O'Donnell, Christopher J; Yin, Xiaoyan; Hirschhorn, Joel N; Newton-Cheh, Christopher; Drake, Jared A; Musone, Stacey L; Heard-Costa, Nancy L; Benjamin, Emelia J; Levy, Daniel; Atwood, Larry D; Wang, Thomas J; Kathiresan, Sekar

2007-06-12

The blood pressure (BP) and heart rate responses to exercise treadmill testing predict incidence of cardiovascular disease, but the genetic determinants of hemodynamic and chronotropic responses to exercise are largely unknown. We assessed systolic BP, diastolic BP, and heart rate during the second stage of the Bruce protocol and at the third minute of recovery in 2982 Framingham Offspring participants (mean age 43 years; 53% women). With use of residuals from multivariable models adjusted for clinical correlates of exercise treadmill testing responses, we estimated the heritability (variance-components methods), genetic linkage (multipoint quantitative trait analyses), and association with 235 single-nucleotide polymorphisms in 14 candidate genes selected a priori from neurohormonal pathways for their potential role in exercise treadmill testing responses. Heritability estimates for heart rate during exercise and during recovery were 0.32 and 0.34, respectively. Heritability estimates for BP variables during exercise were 0.25 and 0.26 (systolic and diastolic BP) and during recovery, 0.16 and 0.13 (systolic and diastolic BP), respectively. Suggestive linkage was found for systolic BP during recovery from exercise (locus 1q43-44, log-of-the-odds score 2.59) and diastolic BP during recovery from exercise (locus 4p15.3, log-of-the-odds score 2.37). Among 235 single-nucleotide polymorphisms tested for association with exercise treadmill testing responses, the minimum nominal probability value was 0.003, which was nonsignificant after adjustment for multiple testing. Hemodynamic and chronotropic responses to exercise are heritable and demonstrate suggestive linkage to select loci. Genetic mapping with newer approaches such as genome-wide association may yield novel insights into the physiological responses to exercise.

Utility of the exercise electrocardiogram testing in sudden cardiac death risk stratification.

PubMed

Refaat, Marwan M; Hotait, Mostafa; Tseng, Zian H

2014-07-01

Sudden cardiac death (SCD) remains a major public health problem. Current established criteria identifying those at risk of sudden arrhythmic death, and likely to benefit from implantable cardioverter defibrillators (ICDs), are neither sensitive nor specific. Exercise electrocardiogram (ECG) testing was traditionally used for information concerning patients' symptoms, exercise capacity, cardiovascular function, myocardial ischemia detection, and hemodynamic responses during activity in patients with hypertrophic cardiomyopathy. We conducted a systematic review of MEDLINE on the utility of exercise ECG testing in SCD risk stratification. Exercise testing can unmask suspected primary electrical diseases in certain patients (catecholaminergic polymorphic ventricular tachycardia or concealed long QT syndrome) and can be effectively utilized to risk stratify patients at an increased (such as early repolarization syndrome and Brugada syndrome) or decreased risk of SCD, such as the loss of preexcitation on exercise testing in asymptomatic Wolff-Parkinson-White syndrome. Exercise ECG testing helps in SCD risk stratification in patients with and without arrhythmogenic hereditary syndromes. © 2014 Wiley Periodicals, Inc.

Effective use of interpreters by family nurse practitioner students: is didactic curriculum enough?

PubMed

Phillips, Susanne J; Lie, Desiree; Encinas, Jennifer; Ahearn, Carol Sue; Tiso, Susan

2011-05-01

Nurse practitioners (NPs) care for patients with limited English proficiency (LEP). However, NP education for improving communication in interpreted encounters is not well reported. We report a single school study using standardized encounters within a clinical practice examination (CPX) to assess the adequacy of current curriculum. Entering family NP (FNP) students (n=26) participated in a baseline CPX case. They were assessed by standardized patients using the validated Interpreter Impact Rating Scale (IIRS) and Physician-Patient Interaction (PPI) scale, and by interpreters using the Interpreter Scale (IS).The case was re-administered to 31 graduating students following completion of existing curriculum. Primary outcome was aggregate change in skills comprising global IIRS, PPI and IS scores. Pre- and post-performance data were available for one class of 10 students. Secondary outcome was change in skill scores for this class. Mean aggregate global scores showed no significant improvement between scores at entry and graduation. For 10 students with pre- and post-performance data, there was no improvement in skill scores for any measure. Skill assessed on one measure worsened. FNP students show no improvement in skills in working with interpreters with the current curriculum. An enhanced curriculum is needed. ©2011 The Author(s) Journal compilation ©2011 American Academy of Nurse Practitioners.

Wolff-Parkinson-White syndrome: a single exercise stress test might be misleading.

PubMed

Salavitabar, Arash; Silver, Eric S; Liberman, Leonardo

2017-05-01

Risk stratification of patients with Wolff-Parkinson-White syndrome for sudden death is a complex process, particularly in understanding the utility of the repeat exercise stress test. We report a case of an 18-year-old patient who was found to have a high-risk pathway by both invasive and exercise stress testing after an initial exercise stress test showing beat-to-beat loss of pre-excitation.

Creatine kinase response to high-intensity aerobic exercise in adult-onset muscular dystrophy.

PubMed

Andersen, Søren P; Sveen, Marie-Louise; Hansen, Regitze S; Madsen, Karen L; Hansen, Jonas B; Madsen, Mads; Vissing, John

2013-12-01

We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies. Fourteen patients with Becker (BMD), facioscapulohumeral (FSHD), or limb-girdle type 2 (LGMD2) muscular dystrophy, and 8 healthy subjects performed 5 cycling tests: an incremental max test, and tests at 65%, 75%, 85%, and 95% of maximal oxygen uptake (VO2max ). Heart rate and oxygen consumption were measured during the tests, and plasma CK was measured before, immediately after, and 24 hours after exercise. All subjects were able to perform high-intensity exercise at the different levels. In patients with LGMD2 and FSHD, CK normalized 24 hours after exercise compared with the pre-exercise value, whereas those with BMD and healthy controls had elevated CK values 24 hours after exercise. The findings suggest that high-intensity exercise is generally well tolerated in patients with LGMD2 and FSHD, whereas those with BMD may be more prone to exercise-induced damage. Copyright © 2013 Wiley Periodicals, Inc.

[Predictors of cardiac arrhythmias in patients with arterial hypertension during exercise stress testing].

PubMed

Kolesnik, M Iu; Sokolova, M V

2014-02-01

Arterial hypertension is an important risk factor for atrial and ventricular arrhythmias. 203 male patients were examined in order to identify predictors of cardiac arrhythmias in patients with arterial hypertension during exercise stress testing. All participants were studied by 24-hour ambulatory blood pressure monitoring, transthoracic echocardiography, an ultrasound scan of the carotid arteries and treadmill test. 47,3% of patients presented cardiac arrhythmias during exercise stress testing. The left ventricular mass, diastolic function and carotid intima-media thickness were found to be independent predictors of exercise-induced arrhythmias. The use of the exercise stress testing may be reasonable for additional risk stratification in hypertensive patients.

Differential Effects of Acute and Regular Physical Exercise on Cognition and Affect

PubMed Central

Hopkins, Michael E.; Davis, F. Caroline; VanTieghem, Michelle R.; Whalen, Paul J.; Bucci, David J.

2012-01-01

The effects of regular exercise versus a single bout of exercise on cognition, anxiety, and mood were systematically examined in healthy, sedentary young adults who were genotyped to determine brain-derived neurotrophic factor (BDNF) allelic status (i.e., Val-Val or Val66Met polymorphism). Participants were evaluated on novel object recognition (NOR) memory and a battery of mental health surveys before and after engaging in either a) a four-week exercise program, with exercise on the final test day, b) a four-week exercise program, without exercise on the final test day, c) a single bout of exercise on the final test day, or d) remaining sedentary between test days. Exercise enhanced object recognition memory and produced a beneficial decrease in perceived stress, but only in participants who exercised for four weeks including the final day of testing. In contrast, a single bout of exercise did not affect recognition memory and resulted in increased perceived stress levels. An additional novel finding was that the improvements on the NOR task were observed exclusively in participants who were homozygous for the BDNF Val allele, indicating that altered activity-dependent release of BDNF in Met allele carriers may attenuate the cognitive benefits of exercise. Importantly, exercise-induced changes in cognition were not correlated with changes in mood/anxiety, suggesting that separate neural systems mediate these effects. These data in humans mirror recent data from our group in rodents. Taken together, these current findings provide new insights into the behavioral and neural mechanisms that mediate the effects of physical exercise on memory and mental health in humans. PMID:22554780

Acute exercise performed close to the anaerobic threshold improves cognitive performance in elderly females.

PubMed

Córdova, C; Silva, V C; Moraes, C F; Simões, H G; Nóbrega, O T

2009-05-01

The objective of the present study was to compare the effect of acute exercise performed at different intensities in relation to the anaerobic threshold (AT) on abilities requiring control of executive functions or alertness in physically active elderly females. Forty-eight physically active elderly females (63.8 +/- 4.6 years old) were assigned to one of four groups by drawing lots: control group without exercise or trial groups with exercise performed at 60, 90, or 110% of AT (watts) and submitted to 5 cognitive tests before and after exercise. Following cognitive pretesting, an incremental cycle ergometer test was conducted to determine AT using a fixed blood lactate concentration of 3.5 mmol/L as cutoff. Acute exercise executed at 90% of AT resulted in significant (P < 0.05, ANOVA) improvement in the performance of executive functions when compared to control in 3 of 5 tests (verbal fluency, Tower of Hanoi test (number of movements), and Trail Making test B). Exercising at 60% of AT did not improve results of any tests for executive functions, whereas exercise executed at 110% of AT only improved the performance in one of these tests (verbal fluency) compared to control. Women from all trial groups exhibited a remarkable reduction in the Simple Response Time (alertness) test (P = 0.001). Thus, physical exercise performed close to AT is more effective to improve cognitive processing of older women even if conducted acutely, and using a customized exercise prescription based on the anaerobic threshold should optimize the beneficial effects.

Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise

NASA Astrophysics Data System (ADS)

Baum, K.; Essfeld, D.; Stegemann, J.

To investigate the effect of μg-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and μg- exercise.

[Exercise stress test and dobutamine stress echocardiography for the prognostic stratification after uncomplicated acute myocardial infarction].

PubMed

Vitiello, Nicola; Cirillo, Raffaele; Granato, Luigi; Coppola, Vincenzo; di Palma, Francesco

2007-05-01

Exercise stress test and dobutamine stress echocardiography are usually performed early after an uncomplicated acute myocardial infarction in the prognostic stratification of patients to define the optimal diagnostic and therapeutic procedure. The aim of this study was to evaluate if the association of an imaging test could increase exercise test capability to identify patients with residual ischemia and patients at high risk of events in the follow-up. Four hundred and forty-two consecutive patients underwent exercise stress testing and dobutamine stress echocardiography before discharge and subsequently coronary angiography within 30 days. In case of submaximal negative result at the exercise test, this was repeated 20 days after discharge. The follow-up lasted 26.8 +/- 9 months. The endpoints were death, reinfarction, and unstable angina requiring hospitalization or revascularization intervention. Both tests and their association showed a higher sensitivity in males; in females dobutamine stress echocardiography had a higher specificity. In females, the addition of dobutamine stress echocardiography increased either the negative or the positive prognostic values of exercise stress test by 31% and 5.6%, respectively. In males, the negative prognostic value increased by 15.5%, whereas the positive prognostic value decreased by 12%. A low exercise capability (<6 METs) showed an event predictive value independent of test results and any other variables. The event-free survival curves correlated with exercise capability differed shortly after the first months both in males and females. These results suggest different stratification procedures with regard to gender: in males, the exercise stress test might be sufficient at discharge, to be repeated 20 days later, if submaximal negative. In females, it seems to be useful to associate an imaging test at discharge. In any case, the exercise stress test remains the main step in the stratification procedure also for its capability to identify patients who are at high risk of events in the follow-up.

Exercise testing after beta-blockade: improved specificity and predictive value in detecting coronary heart disease.

PubMed Central

Marcomichelakis, J; Donaldson, R; Green, J; Joseph, S; Kelly, H B; Taggart, P; Somerville, W

1980-01-01

The value of exercise testing in detecting myocardial ischaemia resulting from coronary atheroma remains controversial. In order to increase the reliability of exercise testing, all its components (asymptomatic, haemodynamic, and electrocardiographic) have been scrutinised. In this study, concerned only with the electrocardiographic response to exercise, the incorporation of beta-blockade into the standard exercise procedure has improved specificity and predictive value without affecting sensitivity. Fifty patients with anginal pain and 50 asymptomatic subjects with an abnormal electrocardiogram were investigated by exercise testing before and after beta-blockade (oxprenolol). All subjects had coronary arteriograms and left ventriculograms, and the results of exercise testing were related to the presence or absence of obstructive coronary artery disease. Possible causes of false positive exercise tests were eliminated by echocardiography. Though beta-blockade was unreliable in distinguishing ischaemic from non-ischaemic resting electrocardiograms, it eliminated all the false positive electrocardiographic responses to exercise in both groups and did not abolish any of the true positive electrocardiographic responses. Thus, specificity and predictive value were improved without reduction in sensitivity. This technique may not necessarily be applicable to other groups of patients or to a random population, but the results of this study suggest it will be a useful additional routine procedure in the investigation of coronary heart disease. PMID:7437172

Application of exercise ECG stress test in the current high cost modern-era healthcare system.

PubMed

Vaidya, Gaurang Nandkishor

Exercise electrocardiogram (ECG) tests boasts of being more widely available, less resource intensive, lower cost and absence of radiation. In the presence of a normal baseline ECG, an exercise ECG test is able to generate a reliable and reproducible result almost comparable to Technitium-99m sestamibi perfusion imaging. Exercise ECG changes when combined with other clinical parameters obtained during the test has the potential to allow effective redistribution of scarce resources by excluding low risk patients with significant accuracy. As we look towards a future of rising healthcare costs, increased prevalence of cardiovascular disease and the need for proper allocation of limited resources; exercise ECG test offers low cost, vital and reliable disease interpretation. This article highlights the physiology of the exercise ECG test, patient selection, effective interpretation, describe previously reported scores and their clinical application in today's clinical practice. Copyright © 2017. Published by Elsevier B.V.

The Effect of Pretest Exercise on Baseline Computerized Neurocognitive Test Scores.

PubMed

Pawlukiewicz, Alec; Yengo-Kahn, Aaron M; Solomon, Gary

2017-10-01

Baseline neurocognitive assessment plays a critical role in return-to-play decision making following sport-related concussions. Prior studies have assessed the effect of a variety of modifying factors on neurocognitive baseline test scores. However, relatively little investigation has been conducted regarding the effect of pretest exercise on baseline testing. The aim of our investigation was to determine the effect of pretest exercise on baseline Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores in adolescent and young adult athletes. We hypothesized that athletes undergoing self-reported strenuous exercise within 3 hours of baseline testing would perform more poorly on neurocognitive metrics and would report a greater number of symptoms than those who had not completed such exercise. Cross-sectional study; Level of evidence, 3. The ImPACT records of 18,245 adolescent and young adult athletes were retrospectively analyzed. After application of inclusion and exclusion criteria, participants were dichotomized into groups based on a positive (n = 664) or negative (n = 6609) self-reported history of strenuous exercise within 3 hours of the baseline test. Participants with a positive history of exercise were then randomly matched, based on age, sex, education level, concussion history, and hours of sleep prior to testing, on a 1:2 basis with individuals who had reported no pretest exercise. The baseline ImPACT composite scores of the 2 groups were then compared. Significant differences were observed for the ImPACT composite scores of verbal memory, visual memory, reaction time, and impulse control as well as for the total symptom score. No significant between-group difference was detected for the visual motor composite score. Furthermore, pretest exercise was associated with a significant increase in the overall frequency of invalid test results. Our results suggest a statistically significant difference in ImPACT composite scores between individuals who report strenuous exercise prior to baseline testing compared with those who do not. Since return-to-play decision making often involves documentation of return to neurocognitive baseline, the baseline test scores must be valid and accurate. As a result, we recommend standardization of baseline testing such that no strenuous exercise takes place 3 hours prior to test administration.

Myocardial perfusion imaging in patients with a recent, normal exercise test.

PubMed

Bovin, Ann; Klausen, Ib C; Petersen, Lars J

2013-03-26

To investigate the added value of myocardial perfusion scintigraphy imaging (MPI) in consecutive patients with suspected coronary artery disease (CAD) and a recent, normal exercise electrocardiography (ECG). This study was a retrospective analysis of consecutive patients referred for MPI during a 2-year period from 2006-2007 at one clinic. All eligible patients were suspected of suffering from CAD, and had performed a satisfactory bicycle exercise test (i.e., peak heart rate > 85% of the expected, age-predicted maximum) within 6 mo of referral, their exercise ECG was had no signs of ischemia, there was no exercise-limiting angina, and no cardiac events occurred between the exercise test and referral. The patients subsequently underwent a standard 2-d, stress-rest exercise MPI. Ischemia was defined based on visual scoring supported by quantitative segmental analysis (i.e., sum of stress score > 3). The results of cardiac catheterization were analyzed, and clinical follow up was performed by review of electronic medical files. A total of 56 patients fulfilled the eligibility criteria. Most patients had a low or intermediate ATPIII pre-test risk of CAD (6 patients had a high pre-test risk). The referral exercise test showed a mean Duke score of 5 (range: 2 to 11), which translated to a low post-exercise risk in 66% and intermediate risk in 34%. A total of seven patients were reported with ischemia by MPI. Three of these patients had high ATPIII pre-test risk scores. Six of these seven patients underwent cardiac catheterization, which showed significant stenosis in one patient with a high pre-test risk of CAD, and indeterminate lesions in three patients (two of whom had high pre-test risk scores). With MPI as a gate keeper for catheterization, no significant, epicardial stenosis was observed in any of the 50 patients (0%, 95% confidence interval 0.0 to 7.1) with low to intermediate pre-test risk of CAD and a negative exercise test. No cardiac events occurred in any patients within a median follow up period of > 1200 d. The added diagnostic value of MPI in patients with low or intermediate risk of CAD and a recent, normal exercise test is marginal.

Immediate Effects of Smoking on Cardiorespiratory Responses During Dynamic Exercise: Arm Vs. Leg Ergometry.

PubMed

Chen, Chien-Liang; Tang, Jing-Shia; Li, Ping-Chia; Chou, Pi-Ling

2015-01-01

This study compared the immediate effects of smoking on cardiorespiratory responses to dynamic arm and leg exercises. This randomized crossover study recruited 14 college students. Each participant underwent two sets of arm-cranking (AC) and leg-cycling (LC) exercise tests. The testing sequences of the control trial (participants refrained from smoking for 8 h before testing) and the experimental trial (participants smoked two cigarettes immediately before testing) were randomly chosen. We observed immediate changes in pulmonary function and heart rate variability after smoking and before the exercise test. The participants then underwent graded exercise tests of their arms and legs until reaching exhaustion. We compared the peak work achieved and time to exhaustion during the exercise tests with various cardiorespiratory indices [i.e., heart rate, oxygen consumption (VO2), minute ventilation (VE)]. The differences between the smoking and control trials were calculated using paired t-tests. For the exercise test periods, VO2, heart rate, and VE values were calculated at every 10% increment of the maximal effort time. The main effects of the time and trial, as well as their trial-by-time (4 × 10) interaction effects on the outcome measures, were investigated using repeated measure ANOVA with trend analysis. 5 min after smoking, the participants exhibited reduced forced vital capacities and forced expiratory volumes in the first second (P < 0.05), in addition to elevated resting heart rates (P < 0.001). The high-frequency, low-frequency, and the total power of the heart rate variability were also reduced (P < 0.05) at rest. For the exercise test periods, smoking reduced the time to exhaustion (P = 0.005) and the ventilatory threshold (P < 0.05) in the LC tests, whereas no significant effects were observed in the AC tests. A trend analysis revealed a significant trial-by-time interaction effect for heart rate, VO2, and VE during the graded exercise test (all P < 0.001). Lower VO2 and VE levels were exhibited in the exercise response of the smoking trial than in those of the control LC trials, whereas no discernable inter-trial difference was observed in the AC trials. Moreover, the differences in heart rate and VE response between the LC and AC exercises were significantly smaller after the participants smoked. This study verified that smoking significantly decreased performance and cardiorespiratory responses to leg exercises. However, the negative effects of smoking on arm exercise performance were not as pronounced.

Haleakala clinopyroxenes: harbingers of depth or heralds of rapid crystal growth? (Invited)

NASA Astrophysics Data System (ADS)

Hammer, J. E.; Jacob, S. R.; Welsch, B. T.; Hellebrand, E.; Sinton, J. M.

2013-12-01

At ocean island volcanoes, clinopyroxene-rich ankaramite magmas are thought to sample crystal mushes accumulating at the base of magma reservoirs[1], and to signal the deepening of a magmatic system no longer vigorous enough to sustain a shallow reservoir and compositional steady-state[2]. However, the postshield magma reservoir at Haleakala is inferred to be both relatively shallow and magmatically robust[3], provoking debate as to the depth of origin of its ankaramite lavas[4,5]. We investigate the origin of cpx-rich lavas at Haleakala by examining samples of an ankaramite lava flow using XRF analysis, EPMA, and cpx-liquid thermobarometry[6]. We address the challenge posed by the holocrystalline texture of the Maui ankaramite by calculating arrays of potential liquids falling on mineral control lines away from the whole rock composition. The pressures and temperatures at which cpx-liquid pairs satisfy Fe-Mg equilibrium range from 0-930 MPa and 1140-1285 °C, respectively. The highest values are similar to previous thermobarometry results[5], suggesting an origin for Haleakala ankaramites up to 1370 MPa. Transforming x-ray intensity maps into pressure maps, we find that the spatial distribution of calculated pressure is not consistent with a core-to-rim crystal growth from high to progressively lower pressure. In fact, mingled but texturally distinct phenocryst subdomains yield independent ranges: 400-500 MPa and 600-900 MPa, indicating crustal and mantle depths, respectively. Importantly, the character and magnitudes of elemental covariations (Ti+Al exchanging for Si+Mg in both domains) are similar to those produced in dynamic 1-atm crystallization experiments[7]. The textures and compositional variations suggest that rapid crystal growth produced cpx compositions out of equilibrium with surrounding liquid, and thus beyond reach of accurate thermobarometry[7]. Although our investigation fails to provide tighter constraints on the ankaramite reservoir depth, it opens the intriguing possibility of kinetically-limited phenocryst growth in the enigmatic postshield magma environment at Haleakala. [1]Macdonald GA, Abbott AT, Peterson FL (1983) Volcanoes in the Sea. University of Hawaii Press, Honolulu. [2]Wolfe EW, Wise WS, Dalrymple GB (1997) The Geology and Petrology of Mauna Kea Volcano, Hawaii-- A Study of Postshield Volcanism. U.S. Govt. Printing Office, Washington, D.C. [3]Chen CY, Frey FA, Garcia MO (1990) Evolution of alkalic lavas at Haleakala Volcano, East Maui, Hawaii - Major, trace-element and isotopic constraints. Contrib Mineral Petrol 105:197-218. [4]Bergmanis, EC, Sinton, JM, Trusdell, FA. Rejuvenated volcanism along the southwest rift zone, East Maui, Hawai'i. Bull Volcanol 62:239-255. [5]Chatterjee N, Bhattacharji S, Fein C (2005) Depth of alkalic magma reservoirs beneath Kolekole cinder cone, Southwest rift zone, East Maui, Hawaii. J Volcanol Geotherm Res 145:1-22. [6]Putirka K (2008) Thermometers and barometers for volcanic systems. RiMG 69:61-120. [7]Mollo S, Del Gaudio P, Ventura G, Iezzi G, Scarlato P (2010) Dependence of clinopyroxene composition on cooling rate in basaltic magmas: Implications for thermobarometry. Lithos 118:302-312.

Evidence for metasomatic enrichment in the oceanic lithosphere and implication for the generation of intraplate basalts

NASA Astrophysics Data System (ADS)

Pilet, S.; Buchs, D.; Cosca, M. A.; Baumgartner, P.

2011-12-01

Petrological studies play a significant role in the debate regarding the origin of intraplate magmas by providing unequivocal constraints about the source(s) composition and melting processes related to basalt formation. Two major hypotheses are currently in debate: first, intraplate magmas are produced at depth (i.e. within the asthenosphere) by low-degrees melting of an enriched peridotitic source in the presence of CO2 [1]; second, alkaline magmas are produced by the melting of metasomatic hydrous veins present within the lithospheric mantle [2]. If the existence of metasomatic veins in the continental lithospheric mantle is well documented, their existence and the mechanism of their formation in an oceanic setting are still mostly unconstrained. Here we report new petrological data demonstrating that metasomatic veins can be produced within the oceanic lithosphere by percolation and differentiation of low-degree melts initially located in the low velocity zone [3]. The existence of metasomatic veins in the oceanic lithosphere is documented by cpx xenocrysts in accreted basaltic sills from northern Costa Rica. New field observations, 40Ar-39Ar radiometric dating, biostratigraphic ages and geochemical analyses indicate that the sills represent a possible, ancient analogue of petit-spot volcanoes produced off Japan by oceanic plate flexure [4]. The cpx xenocrysts are interpreted as a relic of metasomatic veins based on their composition, which is similar to that of cpx from metasomatic veins observed in mantle outcrops and xenoliths. The major and trace element contents of the studied cpx xenocrysts indicate that they crystallized at high pressure in a differentiated liquid. This liquid represents the last stage of a fractional crystallization process that produced early anhydrous cumulates followed by later hydrous cumulates, a mechanism similar to that proposed by Harte et al. [5] for the formation of metasomatic veins in the continental lithosphere. Monte Carlo simulation of this process indicates that the differentiation of low degree melts can produce metasomatic cumulates with a mineralogical and chemical composition suitable to be a source for alkaline rocks observed in an oceanic setting [6]. The presence of low degree melts at the base of the lithosphere has been recently suggested to explain the occurrence of the ubiquitous low seismic velocity zone at the base of the oceanic lithosphere [3]. We propose that tectonic processes such as plate flexure [4] or/and small scale mantle convection [7] can allow these melts to percolate and differentiate across the lithosphere to form metasomatic cumulates (i.e. veins). Such cumulates are likely to represent a potential source of alkaline rocks observed in intraplate ocean volcanoes, especially those produced by low volumes of magma. [1] Dasgupta et al. (2007) J. of Petrol. 48, 2093; [2] Pilet et al. (2008) Science 320, 916; [3] Kawakatsu et al. (2009) Science 324, 499; [4] Hirano et al. (2006) Science 313, 1426 ; [5] Harte et al. (1993) Phil. Trans. Royal Soc. of London, Series A 342, 1; [6] Pilet et al. (2011) J. of Petrol. doi:10.1093/petrology/egr007; [7] Ballmer et al. (2009) G3 doi:10.1029/2009GC002386.

Textural and compositional characteristics of mantle xenoliths from southeastern Libya: Evidence of mantle refertilization processes

NASA Astrophysics Data System (ADS)

Radivojević, Maša; Erić, Suzana; Turki, Salah M.; Toljić, Marinko; Cvetković, Vladica

2014-05-01

The study presents the very first data on mantle xenoliths of the Wādi Eghei area, southeastern Libya. These dm- to cm-sized xenoliths are found in a small volcanic cone of Pliocene basalts, which is situated on the northeastern slopes of the Tibesti Mountains. The host basalts originated from near primary magmas derived by melting of an enriched and garnet-bearing mantle source in within-plate geotectonic settings. Generally, the Wādi Eghei xenoliths can be divided into two texturally different groups: i) well-equilibrated, undeformed protogranular xenoliths, and ii) moderately/strongly sheared, porphyroclastic/equigranular types. Despite their textural diversity, all xenoliths are anhydrous clinopyroxene (cpx)-rich lherzolites, except one protogranular sample (V-5) that can be classified as cpx-poor lherzolite or harzburgite (≡5% of modal cpx). In terms of mineral chemistry, the protogranular xenoliths display only slightly more depleted compositions compared to sheared xenoliths, with sample V-5 as always the most depleted of the whole suite. Fo contents in olivine from protogranular and sheared xenoliths range 90.5-91.0 (V-5~91.5). Orthopyroxene (opx) from protogranular samples has higher Mg#(Mg#=100*Mg/[Mg+Fetot]mol%) from 90.5 to 91.2 (91.8 for V-5 opx), than those from deformed xenoliths (Mg#=89.5-90.5). The composition of spinel also correlates with the texture of the xenoliths. Spinel from the undeformed samples has Cr#s(Cr#=100*Cr/[Cr+Al]mol%) mostly ranging 12-14 (V-5~16), whereas Cr# in spinel occurring in sheared xenoliths is always <10. The variations in cpx composition do not show discernible textural dependences. They display a wide compositional range: En=45.5-50.2; Fs=3.7-5.7; Wo=42.0-50.1. The contents of Al2O3, Na2O and TiO2 range from 2.32-7.75 wt.%, 0.96-1.79 wt.%, and 0.2-0.84 wt.%, respectively. Calculated temperatures indicate that the undeformed types of xenoliths equilibrated at slightly higher temperatures (with minimal and maximal temperatures ranging from 850-950°C, and from 1000 to 1130 °C, respectively), than deformed types (757-923°C and 900-980°C). In addition, among the protogranular xenoliths, a clear dependence of degree of fertility and calculated temperatures is established, with the most fertile samples having the highest equilibrium temperatures. The first data on modal and mineral chemistry compositions of mantle xenoliths from the Wādi Eghei area indicate that this mantle segment underneath southeastern Libya is too fertile to represent a 'normal' subcontinental mantle. The enrichment is most probably related to mafic metasomatisic processes, i.e. to percolations of mafic alkaline magma, similar in composition to the host basalts. The effects of similar mafic metasomatism are also recorded in mantle xenoliths from other localities in Libya. Further analyses, including whole rock, trace element and isotope compositions are in progress and will provide more details about these refertilization processes.

Oxidative stress in response to aerobic and anaerobic power testing: influence of exercise training and carnitine supplementation.

PubMed

Bloomer, Richard J; Smith, Webb A

2009-01-01

The purpose of this study is to compare the oxidative stress response to aerobic and anaerobic power testing, and to determine the impact of exercise training with or without glycine propionyl-L-carnitine (GPLC) in attenuating the oxidative stress response. Thirty-two subjects were assigned (double blind) to placebo, GPLC-1 (1g PLC/d), GPLC-3 (3g PLC/d) for 8 weeks, plus aerobic exercise. Aerobic (graded exercise test: GXT) and anaerobic (Wingate cycle) power tests were performed before and following the intervention. Blood was taken before and immediately following exercise tests and analyzed for malondialdehyde (MDA), hydrogen peroxide (H2O2), and xanthine oxidase activity (XO). No interaction effects were noted. MDA was minimally effected by exercise but lower at rest for both GPLC groups following the intervention (p = 0.044). A time main effect was noted for H2O2 (p = 0.05) and XO (p = 0.003), with values increasing from pre- to postexercise. Both aerobic and anaerobic power testing increase oxidative stress to a similar extent. Exercise training plus GPLC can decrease resting MDA, but it has little impact on exercise-induced oxidative stress biomarkers.

Altered gas-exchange at peak exercise in obese adolescents: implications for verification of effort during cardiopulmonary exercise testing.

PubMed

Marinus, Nastasia; Bervoets, Liene; Massa, Guy; Verboven, Kenneth; Stevens, An; Takken, Tim; Hansen, Dominique

2017-12-01

Cardiopulmonary exercise testing is advised ahead of exercise intervention in obese adolescents to assess medical safety of exercise and physical fitness. Optimal validity and reliability of test results are required to identify maximal exercise effort. As fat oxidation during exercise is disturbed in obese individuals, it remains an unresolved methodological issue whether the respiratory gas exchange ratio (RER) is a valid marker for maximal effort during exercise testing in this population. RER during maximal exercise testing (RERpeak), and RER trajectories, was compared between obese and lean adolescents and relationships between RERpeak, RER slope and subject characteristics (age, gender, Body Mass Index [BMI], Tanner stage, physical activity level) were explored. Thirty-four obese (BMI: 35.1±5.1 kg/m²) and 18 lean (BMI: 18.8±1.9 kg/m²) adolescents (aged 12-18 years) performed a maximal cardiopulmonary exercise test on bike, with comparison of oxygen uptake (VO2), heart rate (HR), expiratory volume (VE), carbon dioxide output (VCO2), and cycling power output (W). RERpeak (1.09±0.06 vs. 1.14±0.06 in obese vs. lean adolescents, respectively) and RER slope (0.03±0.01 vs. 0.05±0.01 per 10% increase in VO2, in obese vs. lean adolescents, respectively) was significantly lower in obese adolescents, and independently related to BMI (P<0.05). Adjusted for HRpeak and VEpeak, RERpeak and RER slope remained significantly lower in obese adolescents (P<0.05). RER trajectories (in relation to %VO2peak and %Wpeak) were significantly different between groups (P<0.001). RERpeak is significantly lowered in obese adolescents. This may have important methodological implications for cardiopulmonary exercise testing in this population.

Adaptation of exercise-induced stress in well-trained healthy young men.

PubMed

JanssenDuijghuijsen, Lonneke M; Keijer, Jaap; Mensink, Marco; Lenaerts, Kaatje; Ridder, Lars; Nierkens, Stefan; Kartaram, Shirley W; Verschuren, Martie C M; Pieters, Raymond H H; Bas, Richard; Witkamp, Renger F; Wichers, Harry J; van Norren, Klaske

2017-01-01

What is the central question of this study? Exercise is known to induce stress-related physiological responses, such as changes in intestinal barrier function. Our aim was to determine the test-retest repeatability of these responses in well-trained individuals. What is the main finding and its importance? Responses to strenuous exercise, as indicated by stress-related markers such as intestinal integrity markers and myokines, showed high test-retest variation. Even in well-trained young men an adapted response is seen after a single repetition after 1 week. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. Strenuous exercise induces different stress-related physiological changes, potentially including changes in intestinal barrier function. In the Protégé Study (ISRCTN14236739; www.isrctn.com), we determined the test-retest repeatability in responses to exercise in well-trained individuals. Eleven well-trained men (27 ± 4 years old) completed an exercise protocol that consisted of intensive cycling intervals, followed by an overnight fast and an additional 90 min cycling phase at 50% of maximal workload the next morning. The day before (rest), and immediately after the exercise protocol (exercise) a lactulose and rhamnose solution was ingested. Markers of energy metabolism, lactulose-to-rhamnose ratio, several cytokines and potential stress-related markers were measured at rest and during exercise. In addition, untargeted urine metabolite profiles were obtained. The complete procedure (Test) was repeated 1 week later (Retest) to assess repeatability. Metabolic effect parameters with regard to energy metabolism and urine metabolomics were similar for both the Test and Retest period, underlining comparable exercise load. Following exercise, intestinal permeability (1 h plasma lactulose-to-rhamnose ratio) and the serum interleukin-6, interleukin-10, fibroblast growth factor-21 and muscle creatine kinase concentrations were significantly increased compared with rest only during the first test and not when the test was repeated. Responses to strenuous exercise in well-trained young men, as indicated by intestinal markers and myokines, show adaptation in Test-Retest outcome. This might be attributable to a carry-over effect of the defense mechanisms triggered during the Test. This finding has implications for the design of studies aimed at evaluating physiological responses to exercise. © 2016 The Authors. Experimental Physiology © 2016 The Physiological Society.

Incidence of Pneumothorax in Patients With Lymphangioleiomyomatosis Undergoing Pulmonary Function and Exercise Testing.

PubMed

Taveira-DaSilva, Angelo M; Julien-Williams, Patricia; Jones, Amanda M; Moss, Joel

2016-07-01

Because pneumothorax is frequent in lymphangioleiomyomatosis, patients have expressed concerns regarding the risk of pneumothorax associated with pulmonary function or exercise testing. Indeed, pneumothorax has been reported in patients with lung disease after both of these tests. The aim of this study was to determine the incidence of pneumothorax in patients with lymphangioleiomyomatosis during admissions to the National Institutes of Health Clinical Research Center between 1995 and 2015. Medical records were reviewed to identify patients who had a pneumothorax during their stay at the National Institutes of Health. A total of 691 patients underwent 4,523 pulmonary function tests and 1,900 exercise tests. Three patients developed pneumothorax after pulmonary function tests and/or exercise tests. The incidence of pneumothorax associated with lung function testing was 0.14 to 0.29 of 100 patients or 0.02 to 0.04 of 100 tests. The incidence of pneumothorax in patients undergoing exercise testing was 0.14 to 0.28 of 100 patients or 0.05 to 0.10 of 100 tests. The risk of pneumothorax associated with pulmonary function or exercise testing in patients with lymphangioleiomyomatosis is low. Published by Elsevier Inc.

Differential effects of acute and regular physical exercise on cognition and affect.

PubMed

Hopkins, M E; Davis, F C; Vantieghem, M R; Whalen, P J; Bucci, D J

2012-07-26

The effects of regular exercise versus a single bout of exercise on cognition, anxiety, and mood were systematically examined in healthy, sedentary young adults who were genotyped to determine brain-derived neurotrophic factor (BDNF) allelic status (i.e., Val-Val or Val66Met polymorphism). Participants were evaluated on novel object recognition (NOR) memory and a battery of mental health surveys before and after engaging in either (a) a 4-week exercise program, with exercise on the final test day, (b) a 4-week exercise program, without exercise on the final test day, (c) a single bout of exercise on the final test day, or (d) remaining sedentary between test days. Exercise enhanced object recognition memory and produced a beneficial decrease in perceived stress, but only in participants who exercised for 4 weeks including the final day of testing. In contrast, a single bout of exercise did not affect recognition memory and resulted in increased perceived stress levels. An additional novel finding was that the improvements on the NOR task were observed exclusively in participants who were homozygous for the BDNF Val allele, indicating that altered activity-dependent release of BDNF in Met allele carriers may attenuate the cognitive benefits of exercise. Importantly, exercise-induced changes in cognition were not correlated with changes in mood/anxiety, suggesting that separate neural systems mediate these effects. These data in humans mirror recent data from our group in rodents. Taken together, these current findings provide new insights into the behavioral and neural mechanisms that mediate the effects of physical exercise on memory and mental health in humans. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Exercise testing in asymptomatic severe aortic stenosis.

PubMed

Magne, Julien; Lancellotti, Patrizio; Piérard, Luc A

2014-02-01

The management and the clinical decision making in asymptomatic patients with aortic stenosis are challenging. An "aggressive" management, including early aortic valve replacement, is debated in these patients. However, the optimal timing for surgery remains controversial due to the lack of prospective data on the determinants of aortic stenosis progression, multicenter studies on risk stratification, and randomized studies on patient management. Exercise stress testing with or without imaging is strictly contraindicated in symptomatic patients with severe aortic stenosis. Exercise stress test is now recommended by current guidelines in asymptomatic patients and may provide incremental prognostic value. Indeed, the development of symptoms during exercise or an abnormal blood pressure response are associated with poor outcome and should be considered as an indication for surgery, as suggested by the most recently updated European Society of Cardiology 2012 guidelines. Exercise stress echocardiography may also improve the risk stratification and identify asymptomatic patients at higher risk of a cardiac event. When the test is combined with imaging, echocardiography during exercise should be recommended rather than post-exercise echocardiography. During exercise, an increase >18 to 20 mm Hg in mean pressure gradient, absence of improvement in left ventricular ejection fraction (i.e., absence of contractile reserve), and/or a systolic pulmonary arterial pressure >60 mm Hg (i.e., exercise pulmonary hypertension) are suggestive signs of advanced stages of the disease and impaired prognosis. Hence, exercise stress test may identify resting asymptomatic patients who develop exercise abnormalities and in whom surgery is recommended according to current guidelines. Exercise stress echocardiography may further unmask a subset of asymptomatic patients (i.e., without exercise stress test abnormalities) who are at high risk of reduced cardiac event free survival. In these patients, early surgery could be beneficial, whereas regular follow-up seems more appropriate in patients without echocardiographic abnormalities during exercise. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Sprint-based exercise and cognitive function in adolescents.

PubMed

Cooper, Simon B; Bandelow, Stephan; Nute, Maria L; Dring, Karah J; Stannard, Rebecca L; Morris, John G; Nevill, Mary E

2016-12-01

Moderate intensity exercise has been shown to enhance cognition in an adolescent population, yet the effect of high-intensity sprint-based exercise remains unknown and was therefore examined in the present study. Following ethical approval and familiarisation, 44 adolescents (12.6 ± 0.6 y) completed an exercise (E) and resting (R) trial in a counter-balanced, randomised crossover design. The exercise trial comprised of 10 × 10 s running sprints, interspersed by 50 s active recovery (walking). A battery of cognitive function tests (Stroop, Digit Symbol Substitution (DSST) and Corsi blocks tests) were completed 30 min pre-exercise, immediately post-exercise and 45 min post-exercise. Data were analysed using mixed effect models with repeated measures. Response times on the simple level of the Stroop test were significantly quicker 45 min following sprint-based exercise (R: 818 ± 33 ms, E: 772 ± 26 ms; p = 0.027) and response times on the complex level of the Stroop test were quicker immediately following the sprint-based exercise (R: 1095 ± 36 ms, E: 1043 ± 37 ms; p = 0.038), while accuracy was maintained. Sprint-based exercise had no immediate or delayed effects on the number of items recalled on the Corsi blocks test (p = 0.289) or substitutions made during the DSST (p = 0.689). The effect of high intensity sprint-based exercise on adolescents' cognitive function was dependant on the component of cognitive function examined. Executive function was enhanced following exercise, demonstrated by improved response times on the Stroop test, whilst visuo-spatial memory and general psycho-motor speed were unaffected. These data support the inclusion of high-intensity sprint-based exercise for adolescents during the school day to enhance cognition.

Genetic testing for exercise prescription and injury prevention: AIS-Athlome consortium-FIMS joint statement.

PubMed

Vlahovich, Nicole; Hughes, David C; Griffiths, Lyn R; Wang, Guan; Pitsiladis, Yannis P; Pigozzi, Fabio; Bachl, Nobert; Eynon, Nir

2017-11-14

There has been considerable growth in basic knowledge and understanding of how genes are influencing response to exercise training and predisposition to injuries and chronic diseases. On the basis of this knowledge, clinical genetic tests may in the future allow the personalisation and optimisation of physical activity, thus providing an avenue for increased efficiency of exercise prescription for health and disease. This review provides an overview of the current status of genetic testing for the purposes of exercise prescription and injury prevention. As such there are a variety of potential uses for genetic testing, including identification of risks associated with participation in sport and understanding individual response to particular types of exercise. However, there are many challenges remaining before genetic testing has evidence-based practical applications; including adoption of international standards for genomics research, as well as resistance against the agendas driven by direct-to-consumer genetic testing companies. Here we propose a way forward to develop an evidence-based approach to support genetic testing for exercise prescription and injury prevention. Based on current knowledge, there is no current clinical application for genetic testing in the area of exercise prescription and injury prevention, however the necessary steps are outlined for the development of evidence-based clinical applications involving genetic testing.

Identification of a Core Set of Exercise Tests for Children and Adolescents with Cerebral Palsy: A Delphi Survey of Researchers and Clinicians

ERIC Educational Resources Information Center

Verschuren, Olaf; Ketelaar, Marjolijn; Keefer, Daniel; Wright, Virginia; Butler, Jane; Ada, Louise; Maher, Carol; Reid, Siobhan; Wright, Marilyn; Dalziel, Blythe; Wiart, Lesley; Fowler, Eileen; Unnithan, Viswanath; Maltais, Desiree B.; van den Berg-Emons, Rita; Takken, Tim

2011-01-01

Aim: Evidence-based recommendations regarding which exercise tests to use in children and adolescents with cerebral palsy (CP) are lacking. This makes it very difficult for therapists and researchers to choose the appropriate exercise-related outcome measures for this group. This study aimed to identify a core set of exercise tests for children…

Central hemodynamic responses during serial exercise tests in heart failure patients using implantable hemodynamic monitors.

PubMed

Ohlsson, A; Steinhaus, D; Kjellström, B; Ryden, L; Bennett, T

2003-06-01

Exercise testing is commonly used in patients with congestive heart failure for diagnostic and prognostic purposes. Such testing may be even more valuable if invasive hemodynamics are acquired. However, this will make the test more complex and expensive and only provides information from isolated moments. We studied serial exercise tests in heart failure patients with implanted hemodynamic monitors allowing recording of central hemodynamics. Twenty-one NYHA Class II-III heart failure patients underwent maximal exercise tests and submaximal bike or 6-min hall walk tests to quantify their hemodynamic responses and to study the feasibility of conducting exercise tests in patients with such devices. Patients were followed for 2-3 years with serial exercise tests. During maximal tests (n=70), heart rate increased by 52+/-19 bpm while S(v)O(2) decreased by 35+/-10% saturation units. RV systolic and diastolic pressure increased 29+/-11 and 11+/-6 mmHg, respectively, while pulmonary artery diastolic pressure increased 21+/-8 mmHg. Submaximal bike (n=196) and hall walk tests (n=172) resulted in S(v)O(2) changes of 80 and 91% of the maximal tests, while RV pressures ranged from 72 to 79% of maximal responses. An added potential value of implantable hemodynamic monitors in heart failure patients may be to quantitatively determine the true hemodynamic profile during standard non-invasive clinical exercise tests and to compare that to hemodynamic effects of regular exercise during daily living. It would be of interest to study whether such information could improve the ability to predict changes in a patient's clinical condition and to improve tailoring patient management.

Train the brain: immediate sensorimotor effects of mentally performed flexor exercises in patients with neck pain. A pilot study.

PubMed

Beinert, Konstantin; Sofsky, Marc; Trojan, Jörg

2018-05-09

Sensorimotor tests, like cranio- cervical flexion and cervical joint position sense tests, share a strong cognitive component during their execution. However, cognitive training for those tests has not been investigated so far. To compare mental and physical exercises for improving the sensorimotor function of the cervical spine. A within-subject design with 16 participants. Outpatient physiotherapy centre. Patients with chronic neck pain. Participants were instructed to perform specific active or mental exercises for the deep and superficial neck flexor muscles. The primary outcomes were cranio-cervical flexion test performance, postural sway, cervical joint position sense and pressure pain threshold. A mixed model analysis was used. The interventions improved cranio-cervical flexion performance (p < 0.001), with no difference between actively or mentally performed exercises. Postural sway increased after actively (p < 0.01) and mentally (p < 0.05) performed deep cervical neck flexor exercises, but not after superficial neck flexor exercises. Mentally performed superficial neck flexor exercises improved cervical joint position sense when compared to mentally performed deep cervical flexor exercises (p < 0.05), and actively performed superficial neck flexor exercises were effective in improving cervical joint position sense acuity compared to mentally performed deep cervical flexor exercises (p < 0.05) for relocation tasks in the transverse plane. The pressure pain threshold at the cervical spine increased after active deep cervical flexor exercises (p < 0.05) and after mental superficial neck flexor exercise (p < 0.05). Mentally performed deep cervical flexor exercises improved cranio-cervical flexion test performance, postural sway and pressure pain threshold at the cervical spine. Mentally performed superficial neck flexor exercises improved cervical joint position sense acuity more than mentally performed deep cervical flexor exercises. Mentally performed exercises are recommended in the early stages of rehabilitation to counteract extensive muscle impairment, and these can be incorporated into daily routine.

What Is Stress Testing?

MedlinePlus

... Research Home / < Back To Health Topics / Stress Testing Stress Testing Also known as What Is Stress Testing? ... test and an imaging stress test. Standard Exercise Stress Test A standard exercise stress test uses an ...

Supervised Phase II Cardiac Exercise Therapy Shortens the Recovery of Exercise Capacity in Patients with Acute Myocardial Infarction

PubMed Central

Lee, Chih-Wei; Wang, Ji-Hung; Hsieh, Jen-Che; Hsieh, Tsung-Cheng; Wu, Yu-Zu; Chen, Tung-Wei; Huang, Chien-Hui

2014-01-01

[Purpose] To investigate the effects of Phase II cardiac exercise therapy (CET) on exercise capacity and changes in coronary risk factors (CRFs) of patients with acute myocardial infarction (AMI). [Subjects] Thirty male subjects with AMI were divided into an experimental group (EG) and a control group (CG). Another 30 age-matched subjects with patent coronary arteries served as a normal-control group (NCG). [Methods] Subjects in EG (n=20) trained using a stationary bicycle for 30 min at their target heart rate twice a week for 8 weeks. Exercise capacity was defined as the maximal metabolic equivalents (METs) that subjects reached during the symptom-limited maximal exercise test. HR, BP and RPP were recorded. Subjects in EG and CG received exercise tests and screening for CRFs at the beginning of, end of, and 3 months after Phase II CET, while subjects in NCG participated only in the 1st test. [Results] METs of CG did not improve until the 3rd test, while RPP at the 2nd test showed a significant increase. However, EG showed increased METs at the 2nd test without increase of RPP, and increased their high density lipoprotein cholesterol (HDL-C) during the follow-up period between the 2nd and 3rd tests. [Conclusion] Phase II CET shortens the recovery time of exercise capacity, helps to maintain the gained exercise capacity and increases HDL-C in phase III. PMID:25276046

A community-based aquatic exercise program to improve endurance and mobility in adults with mild to moderate intellectual disability.

PubMed

Hakim, Renée M; Ross, Michael D; Runco, Wendy; Kane, Michael T

2017-02-01

The purpose of this study was to investigate the impact of a community-based aquatic exercise program on physical performance among adults with mild to moderate intellectual disability (ID). Twenty-two community-dwelling adults with mild to moderate ID volunteered to participate in this study. Participants completed an 8-week aquatic exercise program (2 days/wk, 1 hr/session). Measures of physical performance, which were assessed prior to and following the completion of the aquatic exercise program, included the timed-up-and-go test, 6-min walk test, 30-sec chair stand test, 10-m timed walk test, hand grip strength, and the static plank test. When comparing participants' measures of physical performance prior to and following the 8-week aquatic exercise program, improvements were seen in all measures, but the change in scores for the 6-min walk test, 30-sec chair stand test, and the static plank test achieved statistical significance ( P <0.05). An 8-week group aquatic exercise program for adults with ID may promote improvements in endurance and balance/mobility.

Power of resting echocardiographic measurements to classify pulmonary hypertension patients according to European society of cardiology exercise testing risk stratification cut-offs.

PubMed

Rehman, Michaela B; Garcia, Rodrigue; Christiaens, Luc; Larrieu-Ardilouze, Elisa; Howard, Luke S; Nihoyannopoulos, Petros

2018-04-15

Right ventricular function is the major determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). The ESC risk assessment strategy for PAH is based on clinical status, exercise testing, NTproBNP, imaging and haemodynamics but does not include right ventricular function. Our aims were to test the power of resting echocardiographic measurements to classify PAH patients according to ESC exercise testing risk stratification cut-offs and to determine if the classification power of echocardiographic parameters varied in chronic thrombo-embolic pulmonary hypertension (CTEPH). We prospectively and consecutively recruited 46 PAH patients and 42 CTEPH patients referred for cardio-pulmonary exercise testing and comprehensive transthoracic echocardiography. Exercise testing parameters analyzed were peak oxygen consumption, percentage of predicted maximal oxygen consumption and the slope of ventilation against carbon dioxide production. Receiver operator characteristic curves were used to determine the optimal diagnostic cut-off values of echocardiographic parameters for classifying the patients in intermediate or high risk category according to exercise testing. Measurements of right ventricular systolic function were the best for classifying in PAH (area under the curve 0.815 to 0.935). Measurements of right ventricular pressure overload (0.810 to 0.909) were optimal for classifying according to exercise testing in CTEPH. Measurements of left ventricular function were of no use in either group. Measurements of right ventricular systolic function can classify according to exercise testing risk stratification cut-offs in PAH. However, this is not the case in CTEPH where pressure overload, rather than right ventricular function seems to be linked to exercise performance. Copyright © 2018 Elsevier B.V. All rights reserved.

A Pilot Study for Applying an Extravehicular Activity Exercise Prebreathe Protocol to the International Space Station

NASA Technical Reports Server (NTRS)

Woodruff, Kristin K.; Johnson, Anyika N.; Lee, Stuart M. C.; Gernhardt, Michael; Schneider, Suzanne M.; Foster, Philip P.

2000-01-01

Decompression sickness (DCS) is a serious risk to astronauts performing extravehicular activity (EVA). To reduce this risk, the addition of ten minutes of moderate exercise (75% VO2pk) during prebreathe has been shown to decrease the total prebreathe time from 4 to 2 hours and to decrease the incidence of DCS. The overall purpose of this pilot study was to develop an exercise protocol using flight hardware and an in-flight physical fitness cycle test to perform prebreathe exercise before an EVA. Eleven subjects volunteered to participate in this study. The first objective of this study was to compare the steady-state heart rate (HR) and oxygen consumption (VO2) from a submaximal arm and leg exercise (ALE) session with those predicted from a maximal ALE test. The second objective was to compare the steady-state HR and V02 from a submaximal elastic tube and leg exercise (TLE) session with those predicted from the maximal ALE test. The third objective involved a comparison of the maximal ALE test with a maximal leg-only (LE) test to conform to the in- flight fitness assessment test. The 75% VO2pk target HR from the LE test was significantly less than the target HR from the ALE test. Prescribing exercise using data from the maximal ALE test resulted in the measured submaximal values being higher than predicted VO2 and HR. The results of this pilot study suggest that elastic tubing is valid during EVA prebreathe as a method of arm exercise with the flight leg ergometer and it is recommended that prebreathe countermeasure exercise protocol incorporate this method.

Impact of a community-based exercise programme on physical fitness in middle-aged and older patients with type 2 diabetes.

PubMed

Mendes, Romeu; Sousa, Nelson; Themudo-Barata, José; Reis, Victor

2016-01-01

Physical fitness is related to all-cause mortality, quality of life and risk of falls in patients with type 2 diabetes. This study aimed to analyse the impact of a long-term community-based combined exercise program (aerobic+resistance+agility/balance+flexibility) developed with minimum and low-cost material resources on physical fitness in middle-aged and older patients with type 2 diabetes. This was a non-experimental pre-post evaluation study. Participants (N=43; 62.92±5.92 years old) were engaged in a community-based supervised exercise programme (consisting of combined aerobic, resistance, agility/balance and flexibility exercises; three sessions per week; 70min per session) of 9 months' duration. Aerobic fitness (6-Minute Walk Test), muscle strength (30-Second Chair Stand Test), agility/balance (Timed Up and Go Test) and flexibility (Chair Sit and Reach Test) were assessed before (baseline) and after the exercise intervention. Significant improvements in the performance of the 6-Minute Walk Test (Δ=8.20%, p<0.001), 30-Second Chair Stand Test (Δ=28.84%, p<0.001), Timed Up and Go Test (Δ=14.31%, p<0.001), and Chair Sit and Reach Test (Δ=102.90%, p<0.001) were identified between baseline and end-exercise intervention time points. A long-term community-based combined exercise programme, developed with low-cost exercise strategies, produced significant benefits in physical fitness in middle-aged and older patients with type 2 diabetes. This supervised group exercise programme significantly improved aerobic fitness, muscle strength, agility/balance and flexibility, assessed with field tests in community settings. Copyright © 2016 SESPAS. Published by Elsevier Espana. All rights reserved.

Metabolic myopathies: functional evaluation by different exercise testing approaches.

PubMed

Volpi, L; Ricci, G; Orsucci, D; Alessi, R; Bertolucci, F; Piazza, S; Simoncini, C; Mancuso, M; Siciliano, G

2011-08-01

Metabolic myopathies are a clinically and etiologically heterogeneous group of disorders due to defects in muscular energy metabolism. They include glycogen storage diseases, fatty acid oxidation defects, and mitochondrial disorders. The typical manifestations of a metabolic myopathy are exercise-induced myalgias, exercise intolerance, and cramps. Evaluating subjects with such symptoms is not easy because of the frequent lack of clinical features. Exercise tests are, therefore, reliable screening tools. Here, we discuss the possible role of such exercise testing techniques in the diagnostic approach of a patient with suspected metabolic myopathy.

Mental stress-induced ischemia in patients with coronary artery disease: echocardiographic characteristics and relation to exercise-induced ischemia.

PubMed

Stepanovic, Jelena; Ostojic, Miodrag; Beleslin, Branko; Vukovic, Olivera; Djordjevic-Dikic, Ana; Dikic, Ana Djordjevic; Giga, Vojislav; Nedeljkovic, Ivana; Nedeljkovic, Milan; Stojkovic, Sinisa; Vukcevic, Vladan; Dobric, Milan; Petrasinovic, Zorica; Marinkovic, Jelena; Lecic-Tosevski, Dusica

2012-09-01

The aims of this study were to investigate the incidence and parameters associated with myocardial ischemia during mental stress (MS) as measured by echocardiography and to evaluate the relation between MS-induced and exercise-induced myocardial ischemia. Study participants were 79 patients (63 men; mean [M] [standard deviation {SD}] age = 52 [8] years) with angiographically confirmed coronary artery disease and previous positive exercise test result. The MS protocol consisted of mental arithmetic and anger recall task. The patients performed a treadmill exercise test 15 to 20 minutes after the MS task. Data of post-MS exercise were compared with previous exercise stress test results. The frequency of echocardiographic abnormalities was 35% in response to the mental arithmetic task, compared with 61% with anger recall and 96% with exercise (p < .001, exercise versus MS). Electrocardiogram abnormalities and chest pain were substantially less common during MS than were echocardiographic abnormalities. Independent predictors of MS-induced myocardial ischemia were: wall motion score index at rest (p = .02), peak systolic blood pressure (p = .005), and increase in rate-pressure product (p = .004) during MS. The duration of exercise stress test was significantly shorter (p < .001) when MS preceded the exercise and in the case of earlier exercise (M [SD] = 4.4 [1.9] versus 6.7 [2.2] minutes for patients positive on MS and 5.7 [1.9] versus 8.0 [2.3] minutes for patients negative on MS). Echocardiography can be successfully used to document myocardial ischemia induced by MS. MS-induced ischemia was associated with an increase in hemodynamic parameters during MS and worse function of the left ventricle. MS may shorten the duration of subsequent exercise stress testing and can potentiate exercise-induced ischemia in susceptible patients with coronary artery disease.

Measurement properties of maximal cardiopulmonary exercise tests protocols in persons after stroke: A systematic review.

PubMed

Wittink, Harriet; Verschuren, Olaf; Terwee, Caroline; de Groot, Janke; Kwakkel, Gert; van de Port, Ingrid

2017-11-21

To systematically review and critically appraise the literature on measurement properties of cardiopulmonary exercise test protocols for measuring aerobic capacity, VO2max, in persons after stroke. PubMed, Embase and Cinahl were searched from inception up to 15 June 2016. A total of 9 studies were identified reporting on 9 different cardiopulmonary exercise test protocols. VO2max measured with cardiopulmonary exercise test and open spirometry was the construct of interest. The target population was adult persons after stroke. We included all studies that evaluated reliability, measurement error, criterion validity, content validity, hypothesis testing and/or responsiveness of cardiopulmonary exercise test protocols. Two researchers independently screened the literature, assessed methodological quality using the COnsensus-based Standards for the selection of health Measurement INstruments checklist and extracted data on measurement properties of cardiopulmonary exercise test protocols. Most studies reported on only one measurement property. Best-evidence synthesis was derived taking into account the methodological quality of the studies, the results and the consistency of the results. No judgement could be made on which protocol is "best" for measuring VO2max in persons after stroke due to lack of high-quality studies on the measurement properties of the cardiopulmonary exercise test.

Training with a balance exercise assist robot is more effective than conventional training for frail older adults.

PubMed

Ozaki, Kenichi; Kondo, Izumi; Hirano, Satoshi; Kagaya, Hitoshi; Saitoh, Eiichi; Osawa, Aiko; Fujinori, Yoichi

2017-11-01

To examine the efficacy of postural strategy training using a balance exercise assist robot (BEAR) as compared with conventional balance training for frail older adults. The present study was designed as a cross-over trial without a washout term. A total of 27 community-dwelling frail or prefrail elderly residents (7 men, 20 women; age range 65-85 years) were selected from a volunteer sample. Two exercises were prepared for interventions: robotic exercise moving the center of gravity by the balance exercise assist robot system; and conventional balance training combining muscle-strengthening exercise, postural strategy training and applied motion exercise. Each exercise was carried out twice a week for 6 weeks. Participants were allocated randomly to either the robotic exercise first group or the conventional balance exercise first group. preferred and maximal gait speeds, tandem gait speeds, timed up-and-go test, functional reach test, functional base of support, center of pressure, and muscle strength of the lower extremities were assessed before and after completion of each exercise program. Robotic exercise achieved significant improvements for tandem gait speed (P = 0.012), functional reach test (P = 0.002), timed up-and-go test (P = 0.023) and muscle strength of the lower extremities (P = 0.001-0.030) compared with conventional exercise. In frail or prefrail older adults, robotic exercise was more effective for improving dynamic balance and lower extremity muscle strength than conventional exercise. These findings suggest that postural strategy training with the balance exercise assist robot is effective to improve the gait instability and muscle weakness often seen in frail older adults. Geriatr Gerontol Int 2017; 17: 1982-1990. © 2017 The Authors. Geriatrics & Gerontology International published by John Wiley & Sons Australia, Ltd on behalf of Japan Geriatrics Society.

Metabolic myopathies

NASA Technical Reports Server (NTRS)

Martin, A.; Haller, R. G.; Barohn, R.; Blomqvist, C. G. (Principal Investigator)

1994-01-01

Metabolic myopathies are disorders of muscle energy production that result in skeletal muscle dysfunction. Cardiac and systemic metabolic dysfunction may coexist. Symptoms are often intermittent and provoked by exercise or changes in supply of lipid and carbohydrate fuels. Specific disorders of lipid and carbohydrate metabolism in muscle are reviewed. Evaluation often requires provocative exercise testing. These tests may include ischemic forearm exercise, aerobic cycle exercise, and 31P magnetic resonance spectroscopy with exercise.

Preferred Exertion across Three Common Modes of Exercise Training.

ERIC Educational Resources Information Center

Glass, Stephen C.; Chvala, Angela M.

2001-01-01

Examined the influence of exercise mode on self-selected exercise intensities. Participants performed three types of intensity tests. Researchers collected data on VO2 values continuously and recorded 1-minute averages several times for each submaximal test. Participants allowed to self-select exercise intensity chose work rates within the…

Distractive Auditory Stimuli in the Form of Music in Individuals With COPD: A Systematic Review.

PubMed

Lee, Annemarie L; Desveaux, Laura; Goldstein, Roger S; Brooks, Dina

2015-08-01

Music has been used as a distractive auditory stimulus (DAS) in patients with COPD, but its effects are unclear. This systematic review aimed to establish the effect of DAS on exercise capacity, symptoms, and health-related quality of life (HRQOL) under three conditions: (1) during exercise training, (2) during exercise testing, and (3) for symptom management at rest. Randomized controlled or crossover trials as well as cohort studies of DAS during exercise training, during formal exercise testing, and for symptom management among individuals with COPD were identified from a search of seven databases. Two reviewers independently assessed study quality. Weighted mean differences (WMDs) with 95% CIs were calculated using a random-effects model. Thirteen studies (12 of which were randomized controlled or crossover trials) in 415 participants were included. DAS increased exercise capacity when applied over at least 2 months of exercise training (WMD, 98 m; 95% CI, 47-150 m). HRQOL improved only after a training duration of 3 months. Less dyspnea was noted with DAS during exercise training, but this was not consistently observed in short-term exercise testing or as a symptom management strategy at rest. DAS appears to reduce symptoms of dyspnea and fatigue when used during exercise training, with benefits observed in exercise capacity and HRQOL. When applied during exercise testing, the effects on exercise capacity and symptoms and as a strategy for symptom management at rest are inconsistent.

Effect of energy drink dose on exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise.

PubMed

An, Sang Min; Park, Jong Suk; Kim, Sang Ho

2014-03-01

The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink. The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO2max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO2max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO2max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min. Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg(-1) ingestion of energy drink might be positive effect to increase exercise performance capacity without side-effect in cardiovascular disease.

The influence of exercise on anxiety-like behavior in zebrafish (Danio rerio).

PubMed

DePasquale, C; Leri, J

2018-04-12

In non-human mammals, exercise has been shown to decrease anxiety-like behavior. Conversely, a number of studies have reported no effect or even an increase in anxiety-like behavior after exercise, however, inconsistent training regimes and behavioral paradigms across studies may be confounding the results. Zebrafish (Danio rerio) are a well-established animal model in neurobehavioral research, and have the potential to shed new insight into the effects of exercise on anxiety-like behavior where previous research has been limited, due to the ability to precisely control intensity and duration of exercise, and the validation of tests for measuring different aspects of anxiety-like behaviors. In the current study, fish were split between two treatment groups; Exercised and Control. Fish in the exercised condition were aerobically challenged (max water velocity: 0.5 m/s) using a swim tunnel one hour a day, five days a week, for six weeks. Control fish spent an equal amount of time in the swim tunnel but were not aerobically challenged (max water velocity: 0.05 m/s). After six weeks, all fish were tested individually in two standard complimentary anxiety tests for zebrafish: the novel tank test and the light-dark test. Exercised fish exhibited reduced anxiety-like behaviors in the novel tank test; they spent more time in the top and were quicker to enter the top of a novel tank compared to Control fish. In addition, Exercised fish spent more time in the light compartment of the light-dark test compared to Control fish. Our results demonstrate the beneficial effect of exercise on anxiety-like behavior in zebrafish. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Voluntary exercise offers anxiolytic potential and amplifies galanin gene expression in the locus coeruleus of the rat

PubMed Central

Sciolino, Natale R.; Dishman, Rodney K.; Holmes, Philip V.

2012-01-01

Although exercise improves anxiety in humans, it is controversial whether exercise is anxiolytic in rodents. We tested the hypothesis that stress influences the effect of exercise on anxiety-like and defensive behaviors. To explore the neurobiological mechanisms of exercise, we also examined whether exercise alters gene expression for the stress-related peptide galanin. Rats were housed in the presence or absence of a running wheel for 21 d. A subset of these rats were (1) not injected or received a single high, dose of the β-carboline FG7142 (inverse agonist at the benzodiazepine receptor site) immediately prior to testing or (2) were injected repeatedly with vehicle or FG7142 during the last 10 d of exercise. On day 22, anxiety-like and defensive behaviors were measured in the elevated plus maze, shock probe defensive burying, and defensive withdrawal tests. Locus coeruleus prepro-galanin mRNA was measured by in situ hybridization. Exercise and sedentary rats that were not injected exhibited similar behavior in all tests, whereas FG7142 injected immediately prior to the test battery produced intense avoidance and immobility consistent with an anxiety-like response. However, exercise produced anxiolytic-like and active defensive behaviors in the test battery relative to the sedentary condition in rats injected repeatedly with vehicle or FG7142. Exercise also increased prepro-galanin mRNA in the locus coeruleus relative to sedentary controls. These data suggest that the emergence of enhanced adaptive behavior after chronic voluntary exercise is influenced by stress. Our data support a role for galanin in the beneficial consequences of wheel running. PMID:22580167

Diagnostic Value of Electrocardiogram in Predicting Exaggerated Blood Pressure Response to Exercise Stress Testing.

PubMed

Eshraghi, Ali; Ebdali, Reyhaneh Takalloo; Sajjadi, Seyed Sajed; Golnezhad, Reza

2016-08-01

It is believed that an exaggerated blood pressure response (EBPR) to exercise stress test is associated with a higher risk of cardiovascular events. It is also assumed that QT dispersion (QT-d), which was originally proposed to measure the spatial dispersion of ventricular recovery times, may have a relationship to cardiovascular events. The objective of this study was to examine the difference of changes in QT-d, Maxi-QT, Mini-QT, and QT-c (corrected QT interval) of the electrocardiogram in two groups of patients with exaggerated blood pressure responses (EBPR group) and normal responses (control group) to exercise testing. Also, the diagnostic value of each of these criteria in the prediction of EBPR was studied. This cross-sectional study was conducted from May 2015 to February 2016 on patients suspected of coronary artery disease (CAD) undergoing exercise testing who had been referred to Ghaem and Imam Reza hospitals in Mashhad (Iran). All patients underwent a treadmill exercise test with the 12-lead ECG, which was optically scanned and digitized for analysis of QT-d, QT max, and QT min. Patients were divided into two groups of normal and EBPR to exercise testing. QT changes of ECG were compared between the two groups, and the diagnostic accuracy of QT variables for prediction of EBPR to exercise testing was studied. A multiple linear regression analysis (MLR), Pearson Chi-qquare, independent samples t-test, and receiver operating characteristic (ROC) curve were used as statistical methods in IBM SPSS version 19. Sixty patients (55% male) with a mean age of 50.48 ± 10.89 years were studied in two groups of normal (n=30) and exaggerated blood pressure response (n=30) to exercise testing. Maximum QT and QT dispersion were statistically different in individuals' exaggerated blood pressure response to exercise stress test (p < 0.05). The logistic regression analysis revealed that none of our parameters predicted the EBPR. The ROC curve showed that 50 and 345 milliseconds for QT dispersion and Maxi-QT were the optimal cut-off points for the prediction of EBPR. It seems that Maxi-QT and QT-d may be predictors of EBPR during exercise testing. Also, a significant difference in maxi-QT and QT-d was observed between two groups of patients with normal and EBPR during the exercise testing.

Exercise may cause myocardial ischemia at the anaerobic threshold in cardiac rehabilitation programs.

PubMed

Fuchs, A R C N; Meneghelo, R S; Stefanini, E; De Paola, A V; Smanio, P E P; Mastrocolla, L E; Ferraz, A S; Buglia, S; Piegas, L S; Carvalho, A A C

2009-03-01

Myocardial ischemia may occur during an exercise session in cardiac rehabilitation programs. However, it has not been established whether it is elicited when exercise prescription is based on heart rate corresponding to the anaerobic threshold as measured by cardiopulmonary exercise testing. Our objective was to determine the incidence of myocardial ischemia in cardiac rehabilitation programs according to myocardial perfusion SPECT in exercise programs based on the anaerobic threshold. Thirty-nine patients (35 men and 4 women) diagnosed with coronary artery disease by coronary angiography and stress technetium-99m-sestamibi gated SPECT associated with a baseline cardiopulmonary exercise test were assessed. Ages ranged from 45 to 75 years. A second cardiopulmonary exercise test determined training intensity at the anaerobic threshold. Repeat gated-SPECT was obtained after a third cardiopulmonary exercise test at the prescribed workload and heart rate. Myocardial perfusion images were analyzed using a score system of 6.4 at rest, 13.9 at peak stress, and 10.7 during the prescribed exercise (P < 0.05). The presence of myocardial ischemia during exercise was defined as a difference > or = 2 between the summed stress score and summed rest score. Accordingly, 25 (64%) patients were classified as ischemic and 14 (36%) as nonischemic. MIBI-SPECT showed myocardial ischemia during exercise within the anaerobic threshold. The 64% prevalence of ischemia observed in the study should not be looked on as representative of the whole population of patients undergoing exercise programs. Changes in patient care and exercise programs were implemented as a result of our finding of ischemia during the prescribed exercise.

Individual Characteristics and Unit Performance: A Review of Research and Methods

DTIC Science & Technology

1985-02-01

behavioral segments, improves performance. Simu- lation exercises , especially those employing new high-technology devices, provide surrogate...high-technology training simulation exercise MOB Military Occupational Specialty ORTT Operational Readiness Training Test-a field test REALTRAIN A...REAListic TRAINing simulation exercise SAM Surface-to-Air Missile SAT Scholastic Aptitude Test SQT Skill Qualification Test-an Army performance meas

Towards Solving the Conundrum of Fast-Spread Ocean Crust Formation: Insights from Textural Analysis of Gabbroic Rocks from Pito Deep and Hess Deep, East Pacific Rise

NASA Astrophysics Data System (ADS)

Brown, T. C.; Cheadle, M. J.; John, B. E.; Coogan, L. A.; Gee, J. S.; Karson, J. A.; Meyer, R.; Ceuleneer, G.; Swapp, S.

2014-12-01

Few examples of in situ fast-spread lower ocean crust exist for sampling. Here we present detailed textural analyses of two sample sets that formed at the East Pacific Rise, collected from tectonic windows at Pito (PD) and Hess (HD) deeps. PD samples (collected by ROV) span the upper ~900 m of lower crust. HD samples (collected by seafloor drilling during IODP Exp. 345) come from >1500 m below the sheeted dike gabbro transition (mbsd). PD gabbroic rock textures are consistent with a gabbro glacier flow model generating the uppermost plutonic crust. Shallow samples (41-72 mbsd) likely formed at the distal edge of the magma lens, analogous to similar rocks from Oman. These gabbros are relatively evolved (cpx Mg#75-77, An53-61 and 1-4% Fe-Ti oxides), and have elongate plagioclase grains (aspect ratios up to 1:2:10) exhibiting a strong shape preferred orientation (SPO) with <40% of grains showing dislocation creep textures. Deeper samples (177-876 mbsd) likely began crystallizing in the magma lens then subsided and 'flowed' through the underlying mush zone. These gabbros are more primitive below 386 mbsd (Fo83-88, cpx Mg# 85-89 and An70-82), and plagioclase grains have more equilibrated morphologies (aspect ratios < 1:2:6) that define ~vertical SPOs which increase in strength with depth. Plagioclase exhibits magmatic crystal-lattice preferred orientations (CPOs) which are also vertical. Significantly, the proportion of grains showing dislocation creep textures increases with depth, and plagioclase grain size distributions show a smaller range of sizes at depth; observations that perhaps reflect the effect of increasing strain with depth. IODP Hole U1415I at HD recovered gabbros and troctolitic gabbros from the mid lower crust that show distinctive cm-dm scale modal layering. Strong plagioclase SPOs parallel layering and magmatic CPOs vary dramatically in strength over just 4.5 m of core. Plagioclase grains are relatively equant (aspect ratios < 1:2:4), wrap around large cpx oikocrysts, and exhibit fewer dislocation creep textures than the PD gabbros. These observations perhaps suggest primary crystal accumulation rather than bulk strain/flow. The similar mineralogy and textures of these samples to those from the Rum layered intrusion suggest HD U1415I gabbros may have formed by mid-crust sill injection.

Profile of the HIV epidemic in Cape Verde: molecular epidemiology and drug resistance mutations among HIV-1 and HIV-2 infected patients from distinct islands of the archipelago.

PubMed

de Pina-Araujo, Isabel Inês M; Guimarães, Monick L; Bello, Gonzalo; Vicente, Ana Carolina P; Morgado, Mariza G

2014-01-01

HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010-2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1-75) and 47 (IQR = 12-84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented.

Grain Boundary Sliding in Olivine + Clinopyroxene Aggregates: Weakening Mechanism and Microstructure

NASA Astrophysics Data System (ADS)

Zhao, N.; Hirth, G.; Cooper, R. F.; Kruckenberg, S. C.

2017-12-01

Constraining the viscosity of olivine-rich aggregates is critical for modeling geodynamic processes in the upper mantle. The presence of pyroxenes can complicate the rheology of mantle rocks owing to heterogeneous phase boundary properties and the potential impacts of incompatible elements on interface viscosity. Thus, in the grain boundary sliding (GBS) regime, it may be inappropriate to extrapolate flow laws of end-member aggregates to predict the behavior of multiphase aggregates. We deformed mixtures of fine-grained olivine (Ol) and clinopyroxene (Cpx) with various phase ratios in a general shear geometry at a confining pressure of 1.5 GPa, 1100-1200ºC and strain rate of 10­-3-10-5 s-1 to shear strains up to 8.5. We observed a peak stress followed by weakening in each experiment (except for those at 1200ºC), yet at steady state Ol-Cpx samples are substantially weaker than either pure Ol or pure Cpx end members scaled to the same grain size. Flow law parameters are quantified and indicate that the dominant deformation mechanism is reaction-limited diffusional creep. In addition, the results are consistent with a microphysical model that does not require the diffusion of Si (Sundberg & Cooper, 2008), providing an explanation for the observed weakening of olivine and pyroxene aggregates. Olivine exhibits an axial-[010] fabric or a B-type fabric. Analysis of low-angle (2º-10º) boundary axes indicate the activation of (010)[100] slip system, but no evidence for activation of the (010)[001] slip system that is hypothesized to generate a B-type fabric by dislocation creep. In the samples with strong fabric, we sorted the grains by their grain orientation spread (GOS, a measurement of how substructured the grain is or how active the dislocations were in the grain). The low-GOS grains have smaller grain sizes, smaller aspect ratios and weaker shape preferred orientation compared to high-GOS grains. Yet, low-GOS grains also have the strongest B-type fabric, while high-GOS grains exhibit axial-[010] fabric. These data argue against the hypothesis that olivine B-type fabric forms during GBS as a result of the preferential rotation of grains controlled by crystal habit. We will provide evidence to support that fabric could be related to anisotropy in grain/phase boundary properties (i.e., viscosity and interfacial energy).

Multi-stage metasomatism revealed by trace element and Li isotope distributions in minerals of peridotite xenoliths from Allègre volcano (French Massif Central)

NASA Astrophysics Data System (ADS)

Gu, Xiaoyan; Deloule, Etienne; France, Lydéric; Ingrin, Jannick

2016-11-01

The modal, chemical, and isotopic compositions of mantle peridotite are largely modified by metasomatic processes, which may affect them repeatedly. Xenoliths are commonly used to characterize those metasomatic processes along with the structure, and chemical and isotopic compositions of mantle domains. Nevertheless, the original mantle signatures born by mantle xenoliths are potentially obscured by the interactions occurring between the host magma and the xenolith itself. Here we attempt to identify to which degree the original Li content and isotopic composition, as well as other trace element contents of mantle xenoliths, can be modified by interaction with the host magma. Peridotite xenoliths that have suffered extensive exchange with the entraining magma were sampled in the solidified lava lake of Allègre, Southern French Massif Central, in order to decipher the signature related to peridotite-melt interaction, and to further unravel the evolution of the sub-continental lithospheric mantle. In-situ trace element analyses of clinopyroxene (Cpx) were performed via LA-ICP-MS, and the Li content and isotopic composition of pyroxene and olivine (Ol) via SIMS. Negative HFSE anomalies (Ti/Eu ratios as low as 437) and markedly high LREE/HREE ratios ((La/Yb)N as high as 79) are characteristic of mantle metasomatism at depth. Lithium isotope systematics indicates that at least two different metasomatic events affected the peridotite. Exceptionally high Li contents in Cpx (up to 50 ppm) and slight Li enrichment of Ol rims are ascribed to diffusive Li influx with a positive δ7Li value (+ 3.2‰) from the host magma after entrainment. Conversely, Ol cores preserve extremely light Li isotopic compositions (δ7Li as low as - 25‰) with high Li contents (up to 4.4 ppm) compared to normal mantle, indicating a metasomatic event that occurred before xenolith entrainment. The negative δ7Li signature of this early metasomatism may be related to subduction-related fluids released during the Variscan orogeny. Trace element distributions in minerals reveal that the HFSE and REE composition of Cpx and the negative δ7Li signature in Ol cores were not acquired simultaneously. Therefore at least three successive metasomatic events affected the Allegre peridotites, as revealed through the use of detailed in-situ Li isotopic analyses to trace melt-rock interactions.

Vapor Saturation as The Cause of Volcanic Eruptions at the Lassen Volcanic Center, California, as Inferred from Crystallization Pressures and Temperatures

NASA Astrophysics Data System (ADS)

De Los Reyes, A. M. A.; Putirka, K. D.; Clynne, M. A.; Scruggs, M. A.

2015-12-01

The last three silicic eruptions at the Lassen Volcanic Center occurred at Lassen Peak (27 ka and 1915-17) and Chaos Crags (1103 yrs BP). Klemetti and Clynne (2014) showed that felsic eruptions at Lassen reflect remobilization of resident rhyodacitic crystal mush by intrusion of mafic magma. To better understand the rejuvenation and eruption triggering process, we calculate crystallization temperatures and pressures from clinopyroxene-liquid equilibria on mafic enclaves that provide our closest approach to the composition of mafic magmas delivered to the shallow system. Our goal is to examine whether and to what extent cooling and crystallization occur after recharge, which bears on whether recharge, mixing, or partial crystallization (and consequent vapor saturation) provide the trigger for eruption. We use results from the cpx-liq barometer (1.7 kbar) as input to calculate T for other phases (plagioclase, olivine and amphibole) found in mafic enclave samples. Cpx crystallizes at 1100-1150 oC and olivine precipitates at similar to slightly higher temperatures. Cpx and ol are followed by plagioclase (1000-1050 oC), amphibole (875-1000 oC), and Fe-Ti oxides (1030-1050 oC). These temperatures indicate that recharge magmas are incompletely crystallized as they enter the shallow reservoir of cooler (~725-750 oC, Quinn et al., 2013) felsic crystal mush, and that significant cooling of the mafic magma occurs during mixing and prior to eruption. Such cooling intervals indicate that recharge is not the proximal cause of eruption, but rather that vapor saturation, following a period of mixing and cooling, leads to increased magma overpressure that causes eruption. Interestingly, the Lassen Peak 27 ka volcanics (at 2.09 km3), have a greater volume than either of Chaos Crags (1.2 km3) and the 1915 (0.03 km3) eruption, but our results indicate that their thermal histories are similar. This suggests that while volumes of mafic recharge may control the degree of interaction with felsic crystal mush (e.g., Clynne, 1999), and eventually the volume of erupted magma, recharge volumes do not affect eruption triggering mechanisms. Clynne MA (1999) J. Petrol, 40: 105-132.Klemetti and Clynne, 2014, PLoS One (/12:e113157. doi10.1371/journal.pone0113157)Quinn et al., 2013, AGU Fall Annual Meeting V23C-2848

First myocardial infarction in patients under 60 years old: the role of exercise tests and symptoms in deciding whom to catheterise.

PubMed Central

Cross, S J; Lee, H S; Kenmure, A; Walton, S; Jennings, K

1993-01-01

OBJECTIVE--To determine the role of exercise tests and assessment of angina in the detection of potentially threatening disease in young patients with infarcts. DESIGN--Elective readmission of patients at a mean (SD) of 60 (30) days after acute myocardial infarction for assessment of angina, treadmill exercise tests, and cardiac catheterisation. SETTING--Cardiology department of a teaching hospital. PATIENTS--186 consecutive survivors, aged under 60 years and discharged from the coronary care unit after a first myocardial infarction. MAIN OUTCOME MEASURES--Coronary arteriography, presence of angina, result of exercise tests, and referral for revascularisation. RESULTS--31% of patients had either two vessel disease (with proximal left anterior descending involvement), three vessel disease, or left main stem disease. 49% of all patients had angina. Of the 173 patients who had an exercise test 34% had 1 mm and 24% had 2 mm of exercise induced ST depression. Thirty percent had no angina and a negative exercise test: after a mean (SD) follow up of 16 (4) months none of this symptom free sub-group had died, had experienced a further myocardial infarction, or had been referred for revascularisation. 79% of patients with either two vessel disease (with proximal left anterior descending involvement), three vessel disease, or left main stem disease had either angina or a 1 mm ST depression during the exercise test. CONCLUSION--Patients without cardiac pain after myocardial infarction and without ST changes during an exercise do not need arteriography. PMID:8260273

Acute bouts of wheel running decrease cocaine self-administration: Influence of exercise output.

PubMed

Smith, Mark A; Fronk, Gaylen E; Zhang, Huailin; Magee, Charlotte P; Robinson, Andrea M

Exercise is associated with lower rates of drug use in human populations and decreases drug self-administration in laboratory animals. Most of the existing literature examining the link between exercise and drug use has focused on chronic, long-term exercise, and very few studies have examined the link between exercise output (i.e., amount of exercise) and drug self-administration. The purpose of this study was to examine the effects of acute bouts of exercise on cocaine self-administration, and to determine whether these effects were dependent on exercise output and the time interval between exercise and drug self-administration. Female rats were trained to run in automated running wheels, implanted with intravenous catheters, and allowed to self-administer cocaine on a fixed ratio (FR1) schedule of reinforcement. Immediately prior to each test session, subjects engaged in acute bouts of exercise in which they ran for 0, 30, or 60min at 12m/min. Acute bouts of exercise before test sessions decreased cocaine self-administration in an output-dependent manner, with the greatest reduction in cocaine intake observed in the 60-min exercise condition. Exercise did not reduce cocaine self-administration when wheel running and test sessions were separated by 12h, and exercise did not reduce responding maintained by food or responding during a saline substitution test. These data indicate that acute bouts of exercise decrease cocaine self-administration in a time- and output-dependent manner. These results also add to a growing body of literature suggesting that physical activity may be an effective component of drug abuse treatment programs. Copyright © 2016 Elsevier Inc. All rights reserved.

Exercising attention within the classroom.

PubMed

Hill, Liam; Williams, Justin H G; Aucott, Lorna; Milne, June; Thomson, Jenny; Greig, Jessie; Munro, Val; Mon-Williams, Mark

2010-10-01

to investigate whether increased physical exercise during the school day influenced subsequent cognitive performance in the classroom. a randomized, crossover-design trial (two weeks in duration) was conducted in six mainstream primary schools (1224 children aged 8-11y). No data on sex was available. Children received a teacher-directed, classroom-based programme of physical exercise, delivered approximately 30 minutes after lunch for 15 minutes during one week and no exercise programme during the other (order counterbalanced across participants). At the end of each school day, they completed one of five psychometric tests (paced serial addition, size ordering, listening span, digit-span backwards, and digit-symbol encoding), so that each test was delivered once after exercise and once after no exercise. general linear modelling analysis demonstrated a significant interaction between intervention and counterbalance group (p<0.001), showing that exercise benefitted cognitive performance. Post-hoc analysis revealed that benefits occurred in participants who received the exercise intervention in the second but not the first week of the experiment and were also moderated by type of test and age group. physical exercise benefits cognitive performance within the classroom. The degree of benefit depends on the context of testing and participants' characteristics. This has implications for the role that is attributed to physical exercise within the school curriculum.

Activity restriction in mild COPD: a challenging clinical problem

PubMed Central

O’Donnell, Denis E; Gebke, Kevin B

2014-01-01

Dyspnea, exercise intolerance, and activity restriction are already apparent in mild chronic obstructive pulmonary disease (COPD). However, patients may not seek medical help until their symptoms become troublesome and persistent and significant respiratory impairment is already present; as a consequence, further sustained physical inactivity may contribute to disease progression. Ventilatory and gas exchange impairment, cardiac dysfunction, and skeletal muscle dysfunction are present to a variable degree in patients with mild COPD, and collectively may contribute to exercise intolerance. As such, there is increasing interest in evaluating exercise tolerance and physical activity in symptomatic patients with COPD who have mild airway obstruction, as defined by spirometry. Simple questionnaires, eg, the modified British Medical Research Council dyspnea scale and the COPD Assessment Test, or exercise tests, eg, the 6-minute or incremental and endurance exercise tests can be used to assess exercise performance and functional status. Pedometers and accelerometers are used to evaluate physical activity, and endurance tests (cycle or treadmill) using constant work rate protocols are used to assess the effects of interventions such as pulmonary rehabilitation. In addition, alternative outcome measurements, such as tests of small airway dysfunction and laboratory-based exercise tests, are used to measure the extent of physiological impairment in individuals with persistent dyspnea. This review describes the mechanisms of exercise limitation in patients with mild COPD and the interventions that can potentially improve exercise tolerance. Also discussed are the benefits of pulmonary rehabilitation and the potential role of pharmacologic treatment in symptomatic patients with mild COPD. PMID:24940054

Acute Mucociliary Clearance Response to Aerobic Exercise in Smokers.

PubMed

Ramos, Ercy M C; Vanderlei, Luiz Carlos M; Ito, Juliana T; Lima, Fabiano F; Rodrigues, Fernanda M M; Manzano, Beatriz M; Fernandes, Rômulo A; Cecílio, Michel J; Toledo-Arruda, Alessandra C; Ramos, Dionei

2015-11-01

Mucociliary clearance is the main defense mechanism of the respiratory system, and it is influenced by several stimuli, including aerobic exercise and cigarette smoking. We evaluated the acute response of mucociliary clearance to aerobic exercise in smokers and nonsmokers compared with that found after acute smoking and smoking combined with exercise. Also, we investigated whether there was a correlation between mucociliary clearance and the autonomic nervous system under these conditions. Twenty-one smokers were evaluated for mucociliary clearance by saccharin transit time (STT), and the response of the autonomic nervous system was evaluated by heart rate variability after aerobic exercise, after exercise followed by smoking, after acute smoking, and after rest. For comparison, 17 nonsmokers were also assessed during exercise. Repeated-measures analysis of variance with the Tukey test or the Friedman test followed by the Dunn test was used to evaluate the STT, autonomic response, and other variables to exercise and/or smoking in smokers. A paired t test or Wilcoxon test was used to analyze responses to exercise in nonsmokers. Correlations were evaluated using Pearson or Spearman coefficients. The STT was reduced after exercise in both groups, with similar responses between them. Other stimuli also reduced the STT. The STT showed a negative correlation with sympathetic activity in smokers and a positive correlation with the parasympathetic system in nonsmokers. Although impaired in smokers, mucociliary clearance responded to the stimulus of exercise, as demonstrated by similar STTs compared with nonsmokers. This response was correlated with the autonomic nervous system in both groups. In smokers, mucociliary clearance also responded to the stimuli of smoking and exercise followed by smoking. Copyright © 2015 by Daedalus Enterprises.

The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome.

PubMed

Xian, Hong; Liu, Weijian; Marshall, Cynthia; Chandiramani, Pooja; Bainter, Emily; Martin, Wade H

2016-09-01

Arm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise, but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity. Thus, the purpose of this investigation was to characterize the relationship of peak arm exercise heart rate responses to abnormal stress test findings, coronary revascularization, and mortality in patients unable to perform leg exercise. From 1997 until 2002, arm cycle ergometer stress tests were performed in 443 consecutive veterans age 64.1 yr (11.0 yr) (mean (SD)), of whom 253 also underwent myocardial perfusion imaging (MPI). Patients were categorized by frequency distributions of quartiles of percentage age-predicted peak heart rate (APPHR), heart rate reserve (HRR), and peak heart rate-systolic blood pressure product (PRPP). Exercise-induced ST-segment depression, abnormal MPI findings, coronary revascularization, and 12.0-yr (1.3 yr) Kaplan-Meier all-cause and cardiovascular mortality plots were then characterized by quartiles of APPHR, HRR, and PRPP. A reduced frequency of abnormal arm exercise ECG results was associated only with the lowest quartile of APPHR (≤69%) and HRR (≤43%), whereas higher frequency of abnormal MPI findings exhibited an inverse relationship trend with lower APPHR (P = 0.10) and HRR (P = 0.12). There was a strong inverse association of APPHR, HRR, and PRPP with all-cause (all P ≤ 0.01) and cardiovascular (P < 0.05) mortality. The frequency of coronary revascularization was unrelated to APPHR or HRR. Arm exercise ECG stress test sensitivity is only reduced at ≤69% APPHR or ≤43% HRR, whereas arm exercise MPI sensitivity and referral for coronary revascularization after arm exercise stress testing are not adversely affected by even a severely blunted peak heart rate. However, both all-cause mortality and cardiovascular mortality are strongly and inversely related to APPHR and HRR.

Exercise Prescriptions for Training and Rehabilitation in Patients with Heart and Lung Disease.

PubMed

Palermo, Pietro; Corrà, Ugo

2017-07-01

Rehabilitation in patients with advanced cardiac and pulmonary disease has been shown to increase survival and improve quality of life, among many other benefits. Exercise training is the fundamental ingredient in these rehabilitation programs. However, determining the amount of exercise is not straightforward or uniform. Most rehabilitation and training programs fix the time of exercise and set the exercise intensity to the goals of the rehabilitation program and the exercise-related hurdles of the individual. The exercise training intensity prescription must balance the desired gain in conditioning with safety. Symptom-limited cardiopulmonary exercise testing is the fundamental tool to identify the exercise intensity and define the appropriate training. In addition, cardiopulmonary exercise testing provides an understanding of the systems involved in oxygen transport and utilization, making it possible to identify the factors limiting exercise capacity in individual patients.

Overview of the Exploration Exercise Device Validation Study Plans

NASA Technical Reports Server (NTRS)

DeWitt, J. K.; Swan, B. G.

2018-01-01

The NASA has determined that a multi-functional exercise device will be developed for use as an exercise device during exploration missions. The device will allow for full body resistance and metabolic exercise necessary to minimize physiological losses during space flight and to maintain fitness necessary to perform critical mission tasks. Prior to implementation as an exercise device on an Exploration vehicle, there will be verification and validation testing completed to determine device efficacy at providing the necessary training stimuli to achieve desired goals. Because the exploration device will be new device that has yet be specified, specific Verification and Validation (V&V) protocols have yet to be developed. Upon delivery of an exploration exercise device training unit, stakeholders throughout NASA will develop V&V plans that include ground-based testing and testing on the International Space Station (ISS). Stakeholders will develop test protocols that include success criterion for the device. Ground tests will occur at NASA Johnson Space Station prior to flight testing. The intents of the ground tests are to allow crew, spaceflight medicine, science, engineering, Astronaut Strength, Conditioning, and Reconditioning staff, and others to gain experience in the best utilization of the device. The goal is to obtain an evidence base for recommending use of the device on the ISS. The developed protocol will be created to achieve multiple objectives, including determining if the device provides an adequate training stimulus for 5th - 95th percentile males and females, allows for exercise modalities that protect functional capability, and is robust and can withstand extensive human use. Although protocols are yet to be determined, current expectations include use of the device by test subjects and current crew in order to obtain quantitative and qualitative feedback. Information obtained during the ground tests may be used to influence device modifications during design iterations. Assuming successful ground tests, the device will be installed on the ISS for testing during space flight. Spaceflight testing is envisioned to include an activation and checkout (ACO) phase and a V&V phase. During the ACO phase, 1-2 crewmembers will exercise with the device to ensure proper function. ACO is expected to last multiple months because of the many modes and methods of exercise that need to be assessed. However, the goal is to complete the ACO as quickly as possible. Once successful ACO occurs, the crew will be free to use the device for normal exercise pending concurrence from stakeholders. V&V tests on the ISS will ideally consist of crew using the device for all of their exercise for an entire mission. Exercise prescriptions will be supplied that replicate expected prescriptions during exploration missions. Crew that are not enrolled in the V&V studies would be also free to use the device as their schedule permits. As experience is gained by users, exercise protocols could change. The intent of all V&V testing is to ensure that all have thorough understanding of experience at optimizing device capability

Different distribution patterns of ten virulence genes in Legionella reference strains and strains isolated from environmental water and patients.

PubMed

Zhan, Xiao-Yong; Hu, Chao-Hui; Zhu, Qing-Yi

2016-04-01

Virulence genes are distinct regions of DNA which are present in the genome of pathogenic bacteria and absent in nonpathogenic strains of the same or related species. Virulence genes are frequently associated with bacterial pathogenicity in genus Legionella. In the present study, an assay was performed to detect ten virulence genes, including iraA, iraB, lvrA, lvrB, lvhD, cpxR, cpxA, dotA, icmC and icmD in different pathogenicity islands of 47 Legionella reference strains, 235 environmental strains isolated from water, and 4 clinical strains isolated from the lung tissue of pneumonia patients. The distribution frequencies of these genes in reference or/and environmental L. pneumophila strains were much higher than those in reference non-L. pneumophila or/and environmental non-L. pneumophila strains, respectively. L. pneumophila clinical strains also maintained higher frequencies of these genes compared to four other types of Legionella strains. Distribution frequencies of these genes in reference L. pneumophila strains were similar to those in environmental L. pneumophila strains. In contrast, environmental non-L. pneumophila maintained higher frequencies of these genes compared to those found in reference non-L. pneumophila strains. This study illustrates the association of virulence genes with Legionella pathogenicity and reveals the possible virulence evolution of non-L. pneumophia strains isolated from environmental water.

The evolution and ascent paths of mantle xenolith-bearing magma: Observations and insights from Cenozoic basalts in Southeast China

NASA Astrophysics Data System (ADS)

Sun, Pu; Niu, Yaoling; Guo, Pengyuan; Cui, Huixia; Ye, Lei; Liu, Jinju

2018-06-01

Studies have shown that mantle xenolith-bearing magmas must ascend rapidly to carry mantle xenoliths to the surface. It has thus been inferred inadvertently that such rapid ascending melt must have undergone little crystallization or evolution. However, this inference is apparently inconsistent with the widespread observation that xenolith-bearing alkali basalts are variably evolved with Mg# ≤72. In this paper, we discuss this important, yet overlooked, petrological problem and offer new perspectives with evidence. We analyzed the Cenozoic mantle xenolith-bearing alkali basalts from several locations in Southeast China that have experienced varying degrees of fractional crystallization (Mg# = 48-67). The variably evolved composition of host alkali basalts is not in contradiction with rapid ascent, but rather reflects inevitability of crystallization during ascent. Thermometry calculations for clinopyroxene (Cpx) megacrysts give equilibrium temperatures of 1238-1390 °C, which is consistent with the effect of conductive cooling and melt crystallization during ascent because TMelt > TLithosphere. The equilibrium pressure (18-27 kbar) of these Cpx megacrysts suggests that the crystallization takes place under lithospheric mantle conditions. The host melt must have experienced limited low-pressure residence in the shallower levels of lithospheric mantle and crust. This is in fact consistent with the rapid ascent of the host melt to bring mantle xenoliths to the surface.

Spectrophotometric determination of some histamine H1-antagonists drugs in their pharmaceutical preparations.

PubMed

Hassan, Wafaa S; El-Henawee, Magda M; Gouda, Ayman A

2008-01-01

Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of three histamine H1-antagonists drugs, e.g., chlorphenoxamine hydrochloride (CPX), diphenhydramine hydrochloride (DPH) and clemastine (CMT) in bulk and in their pharmaceutical formulations. The first method depend upon the reaction of molybdenum(V) thiocyanate ions (Method A) with the cited drugs to form stable ion-pair complexes which extractable with methylene chloride, the orange red color complex was determined colorimetrically at lambda(max) 470nm. The second method is based on the formation of an ion-association complex with alizarin red S as chromogenic reagents in acidic medium (Method B), which is extracted into chloroform. The complexes have a maximum absorbance at 425 and 426nm for (DPH or CMT) and CPX, respectively. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration ranges of 5.0-40 and 5-70microgmL(-1) for molybdenum(V) thiocyanate (Method A) and alizarin red S (Method B), respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. Applications of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the procedure was confirmed by applying the standard addition technique and the results obtained in good agreement well with those obtained by the official method.

Spectrophotometric determination of some histamine H1-antagonists drugs in their pharmaceutical preparations

NASA Astrophysics Data System (ADS)

Hassan, Wafaa S.; El-Henawee, Magda M.; Gouda, Ayman A.

2008-01-01

Two rapid, simple and sensitive extractive specrophotometric methods has been developed for the determination of three histamine H1-antagonists drugs, e.g., chlorphenoxamine hydrochloride (CPX), diphenhydramine hydrochloride (DPH) and clemastine (CMT) in bulk and in their pharmaceutical formulations. The first method depend upon the reaction of molybdenum(V) thiocyanate ions (Method A) with the cited drugs to form stable ion-pair complexes which extractable with methylene chloride, the orange red color complex was determined colorimetrically at λmax 470 nm. The second method is based on the formation of an ion-association complex with alizarin red S as chromogenic reagents in acidic medium (Method B), which is extracted into chloroform. The complexes have a maximum absorbance at 425 and 426 nm for (DPH or CMT) and CPX, respectively. Regression analysis of Beer-Lambert plots showed a good correlation in the concentration ranges of 5.0-40 and 5-70 μg mL -1 for molybdenum(V) thiocyanate (Method A) and alizarin red S (Method B), respectively. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. Applications of the procedure to the analysis of various pharmaceutical preparations gave reproducible and accurate results. Further, the validity of the procedure was confirmed by applying the standard addition technique and the results obtained in good agreement well with those obtained by the official method.

Effects of exercise-induced fatigue on postural balance: a comparison of treadmill versus cycle fatiguing protocols.

PubMed

Wright, Katherine E; Lyons, Thomas S; Navalta, James W

2013-05-01

The authors of this study examined the effects of muscle fatigue on balance indices and recovery time in recreationally trained individuals after incremental tests on a treadmill and a cycle ergometer. Sixteen participants (male N = 11, female N = 5) (mean age = 21.2 ± 2 years) completed this study. Balance measures were performed on a Biodex Balance System via the Dynamic Balance Test. Balance was measured pre-exercise, immediately post-exercise, and at 3-, 6-, 9-, 12-, 15-, 18-, and 21-min post-exercise. Immediately following the fatiguing treadmill test, balance increased significantly in the overall stability index (SI) (from 4.38 ± 2.48 to 6.09 ± 1.80) and the anterior/posterior index (API) (from 3.49 ± 2.18 to 5.28 ± 1.81) (p < 0.01). Immediately following the fatiguing cycle test, balance was not altered significantly in SI or API. Balance was not altered significantly for the medial/lateral index for either exercise test at any time point. Additionally, there were no significant differences in time to recovery. At 12-min post-exercise, all indices were below pre-exercise values, indicating that fatiguing exercise has a positive effect on balance over time. These results are consistent with previous research, suggesting that any effects of fatigue on balance are seen immediately and are diminished as time after exercise increases.

Effects of air ventilation during stationary exercise testing.

PubMed

Van Schuylenbergh, R; Vanden Eynde, B; Hespel, P

2004-07-01

The impact of air ventilation on performance and physiological responses during stationary exercise in the laboratory was studied. Fourteen well-trained cyclists performed three exercise tests on a cycle ergometer, each separated by a 1-week interval. The first test was a graded test to determine the power output corresponding with the 4-mmol l(-1) lactate level. Tests 2 and 3 were 30-min constant-load tests at a power output corresponding with this 4-mmol l(-1) lactate threshold. One constant-load test was performed in the absence (NAV), whilst the other was performed in the presence (AV) of air ventilation (3 m s(-1)). During the constant-load tests, heart rate, tympanic temperature, blood lactate concentration and oxygen uptake (VO2) were measured at 10-min intervals and at the end of the test. Differences between the two test conditions were evaluated using paired t-tests. During NAV, 12 subjects interrupted the test due to premature exhaustion (exercise duration <30 min), versus only seven in AV ( P<0.05). At the end of the test tympanic temperature was 35.9 (0.2) degrees C in AV and was higher in NAV [36.7 (0.2) degrees C, P<0.05]. Exercise heart rate increased at a faster rate during NAV [+2.2 (0.3) beats min(-1)] than during AV [+1.5 (0.2) beats min(-1), P<0.05]. Blood lactate concentration and VO2 were similar between conditions. Air ventilation is essential to prevent an upward shift in the lactate:heart rate as well as the power output:heart rate relationship during laboratory exercise testing and indoor exercise training.

Misremembering Past Affect Predicts Adolescents' Future Affective Experience During Exercise.

PubMed

Karnaze, Melissa M; Levine, Linda J; Schneider, Margaret

2017-09-01

Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents' feelings during exercise. During the 1st semester of the school year, we assessed 6th-grade students' (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test and recalled their affect during the fitness test later that semester. During the 2nd semester, the same participants rated their affect during a moderate-intensity exercise task. Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences.

Misremembering Past Affect Predicts Adolescents’ Future Affective Experience during Exercise

PubMed Central

Karnaze, Melissa M.; Levine, Linda J.; Schneider, Margaret

2018-01-01

Purpose Increasing physical activity among adolescents is a public health priority. Because people are motivated to engage in activities that make them feel good, this study examined predictors of adolescents’ feelings during exercise. Method During the first semester of the school year, we assessed sixth grade students’ (N = 136) cognitive appraisals of the importance of exercise. Participants also reported their affect during a cardiovascular fitness test, and recalled their affect during the fitness test later that semester. During the second semester, the same participants rated their affect during a moderate-intensity exercise task. Results Affect reported during the moderate-intensity exercise task was predicted by cognitive appraisals of the importance of exercise, and by misremembering affect during the fitness test as more positive than it actually was. This memory bias mediated the association between appraising exercise as important and experiencing a positive change in affect during the moderate-intensity exercise task. Conclusion These findings highlight the roles of both cognitive appraisals and memory as factors that may influence affect during exercise. Future work should explore whether affect during exercise can be modified by targeting appraisals and memories related to exercise experiences. PMID:28494196

[Development and Evaluation of a Motivational Interviewing Program for Exercise Improvement in Persons with Physical Disabilities].

PubMed

Jeong, Jeong Hee; Jeong, Ihn Sook

2017-06-01

The aims of this study were to develop a motivational interviewing program for exercise improvement in persons with physical disabilities and to examine the effect of this motivational interviewing intervention. The study employed a nonequivalent control group pretest and posttest design. A total of 62 persons with physical disabilities (30 in the experimental group, 32 in the control group) were recruited from 2 community rehabilitation centers. The experimental group received 8 sessions of a group motivational interviewing program, scheduled once a week, with each session lasting 60 minutes. Test measures were completed before the intervention, immediately after the end of the intervention, 2 weeks later, and 6 weeks after the end of the intervention. Measures included self-efficacy for exercise, decisional balance for exercise, stage of change for exercise, regularity of exercise, exercise maintenance, and independent living ability. Data were analyzed using the χ²-test, Fisher's exact test, Independent samples t-test, and repeated measures ANOVA, conducted using IBM SPSS Statistics version 18. The experimental group showed a significant increase in self-efficacy for exercise (F=50.98, p<.001), benefit (pros) of exercise (F=24.16, p<.001), and independent living ability (F=50.94, p<.001), and a significant decrease in loss (cons) of exercise (F=26.50, p<.001). There were significant differences between the two groups in stages of change for exercise (p<.001), regularity of exercise (p<.001), and exercise maintenance (χ²=26.61, p<.001). The motivational interviewing program has the potential to improve exercise levels in persons with physical disabilities. © 2017 Korean Society of Nursing Science

Prevalence of exercise-induced bronchoconstriction and exercise-induced laryngeal obstruction in a general adolescent population.

PubMed

Johansson, Henrik; Norlander, Katarina; Berglund, Lars; Janson, Christer; Malinovschi, Andrei; Nordvall, Lennart; Nordang, Leif; Emtner, Margareta

2015-01-01

Exercise-induced respiratory symptoms are common among adolescents. Exercise is a known stimulus for transient narrowing of the airways, such as exercise-induced bronchoconstriction (EIB) and exercise-induced laryngeal obstruction (EILO). Our aim was to investigate the prevalence of EIB and EILO in a general population of adolescents. In this cross-sectional study, a questionnaire on exercise-induced dyspnoea was sent to all adolescents born in 1997 and 1998 in Uppsala, Sweden (n=3838). A random subsample of 146 adolescents (99 with self-reported exercise-induced dyspnoea and 47 without this condition) underwent standardised treadmill exercise tests for EIB and EILO. The exercise test for EIB was performed while breathing dry air; a positive test was defined as a decrease of ≥10% in FEV1 from baseline. EILO was investigated using continuous laryngoscopy during exercise. The estimated prevalence of EIB and EILO in the total population was 19.2% and 5.7%, respectively. No gender differences were found. In adolescents with exercise-induced dyspnoea, 39.8% had EIB, 6% had EILO and 4.8% had both conditions. In this group, significantly more boys than girls had neither EIB nor EILO (64.7% vs 38.8%; p=0.026). There were no significant differences in body mass index, lung function, diagnosed asthma or medication between the participants with exercise-induced dyspnoea who had or did not have a positive EIB or EILO test result. Both EIB and EILO are common causes of exercise-induced dyspnoea in adolescents. EILO is equally common among girls and boys and can coexist with EIB. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Gender-related associations of genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase and bradykinin B2 receptor with treadmill exercise test responses.

PubMed

Nunes, Rafael Amorim Belo; Barroso, Lúcia Pereira; Pereira, Alexandre da Costa; Krieger, José Eduardo; Mansur, Alfredo José

2014-01-01

Treadmill exercise test responses have been associated with cardiovascular prognosis in individuals without overt heart disease. Neurohumoral and nitric oxide responses may influence cardiovascular performance during exercise testing. Therefore, we evaluated associations between functional genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase, bradykinin receptor B2 and treadmill exercise test responses in men and women without overt heart disease. We enrolled 766 (417 women; 349 men) individuals without established heart disease from a check-up programme at the Heart Institute, University of São Paulo Medical School. Exercise capacity, chronotropic reserve, maximum heart-rate achieved, heart-rate recovery, exercise systolic blood pressure (SBP), exercise diastolic blood pressure (DBP) and SBP recovery were assessed during exercise testing. Genotypes for the α-adrenergic receptors ADRA1A Arg347Cys (rs1048101), ADRA2A 1780 C>T (rs553668), ADRA2B Del 301-303 (rs28365031), endothelial nitric synthase (eNOS) 786 T>C (rs2070744), eNOS Glu298Asp (rs1799983) and BK2R (rs5810761) polymorphisms were assessed by PCR and high-resolution melting analysis. Maximum SBP was associated with ADRA1A rs1048101 (p=0.008) and BK2R rs5810761 (p=0.008) polymorphisms in men and ADRA2A rs553668 (p=0.008) and ADRA2B rs28365031 (p=0.022) in women. Maximum DBP pressure was associated with ADRA2A rs553668 (p=0.002) and eNOS rs1799983 (p=0.015) polymorphisms in women. Exercise capacity was associated with eNOS rs2070744 polymorphisms in women (p=0.01) and with eNOS rs1799983 in men and women (p=0.038 and p=0.024). The findings suggest that genetic variants of α-adrenergic receptors and bradykinin B2 receptor may be involved with blood pressure responses during exercise tests. Genetic variants of endothelial nitric oxide synthase may be involved with exercise capacity and blood pressure responses during exercise tests. These responses may be gender-related.

Gender-related associations of genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase and bradykinin B2 receptor with treadmill exercise test responses

PubMed Central

Nunes, Rafael Amorim Belo; Barroso, Lúcia Pereira; Pereira, Alexandre da Costa; Krieger, José Eduardo; Mansur, Alfredo José

2014-01-01

Background Treadmill exercise test responses have been associated with cardiovascular prognosis in individuals without overt heart disease. Neurohumoral and nitric oxide responses may influence cardiovascular performance during exercise testing. Therefore, we evaluated associations between functional genetic polymorphisms of α-adrenergic receptors, endothelial nitric oxide synthase, bradykinin receptor B2 and treadmill exercise test responses in men and women without overt heart disease. Methods We enrolled 766 (417 women; 349 men) individuals without established heart disease from a check-up programme at the Heart Institute, University of São Paulo Medical School. Exercise capacity, chronotropic reserve, maximum heart-rate achieved, heart-rate recovery, exercise systolic blood pressure (SBP), exercise diastolic blood pressure (DBP) and SBP recovery were assessed during exercise testing. Genotypes for the α-adrenergic receptors ADRA1A Arg347Cys (rs1048101), ADRA2A 1780 C>T (rs553668), ADRA2B Del 301–303 (rs28365031), endothelial nitric synthase (eNOS) 786 T>C (rs2070744), eNOS Glu298Asp (rs1799983) and BK2R (rs5810761) polymorphisms were assessed by PCR and high-resolution melting analysis. Results Maximum SBP was associated with ADRA1A rs1048101 (p=0.008) and BK2R rs5810761 (p=0.008) polymorphisms in men and ADRA2A rs553668 (p=0.008) and ADRA2B rs28365031 (p=0.022) in women. Maximum DBP pressure was associated with ADRA2A rs553668 (p=0.002) and eNOS rs1799983 (p=0.015) polymorphisms in women. Exercise capacity was associated with eNOS rs2070744 polymorphisms in women (p=0.01) and with eNOS rs1799983 in men and women (p=0.038 and p=0.024). Conclusions The findings suggest that genetic variants of α-adrenergic receptors and bradykinin B2 receptor may be involved with blood pressure responses during exercise tests. Genetic variants of endothelial nitric oxide synthase may be involved with exercise capacity and blood pressure responses during exercise tests. These responses may be gender-related. PMID:25544888

Effects of exercise on alterations in redox homeostasis in elite male and female endurance athletes using a clinical point-of-care test.

PubMed

Lewis, Nathan A; Towey, Colin; Bruinvels, Georgie; Howatson, Glyn; Pedlar, Charles R

2016-10-01

Exercise causes alterations in redox homeostasis (ARH). Measuring ARH in elite athletes may aid in the identification of training tolerance, fatigued states, and underperformance. To the best of our knowledge, no studies have examined ARH in elite male and female distance runners at sea level. The monitoring of ARH in athletes is hindered by a lack of reliable and repeatable in-the-field testing tools and by the rapid turnaround of results. We examined the effects of various exercise intensities on ARH in healthy (non-over-reached) elite male and female endurance athletes using clinical point-of-care (POC) redox tests, referred to as the free oxygen radical test (FORT) (pro-oxidant) and the free oxygen radical defence (FORD) (antioxidant). Elite male and female endurance athletes (n = 22) completed a discontinuous incremental treadmill protocol at submaximal running speeds and a test to exhaustion. Redox measures were analyzed via blood sampling at rest, warm-up, submaximal exercise, exhaustion, and recovery. FORD was elevated above rest after submaximal and maximal exercise, and recovery (p < 0.05, d = 0.87-1.55), with only maximal exercise and recovery increasing FORT (p < 0.05, d = 0.23-0.32). Overall, a decrease in oxidative stress in response to submaximal and maximal exercise was evident (p < 0.05, d = 0.46). There were no gender differences for ARH (p > 0.05). The velocity at lactate threshold (vLT) correlated with the FORD response at rest, maximal exercise, and recovery (p < 0.05). Using the clinical POC redox test, an absence of oxidative stress after exhaustive exercise is evident in the nonfatigued elite endurance athlete. The blood antioxidant response (FORD) to exercise appears to be related to a key marker of aerobic fitness: vLT.

Exercise-induced hand tremor: a possible test for beta 2-adrenoceptor selectivity in man?

PubMed Central

Abila, B; Wilson, J F; Marshall, R W; Richens, A

1986-01-01

The effects of intravenous doses of propranolol, sotalol, timolol, atenolol and placebo on exercise-induced tachycardia and exercise-induced increases in hand tremor were assessed in four healthy volunteers. All active drugs produced significant reductions in exercise-induced tachycardia. Exercise caused consistent significant increases in hand tremor which were blocked by the three non-cardioselective drugs but not by atenolol or placebo. The blockade of exercise-induced hand tremor is suggested as a possible test for the assessment of the selectivity of beta-adrenoceptor blockade in man. PMID:2874824

Prospective evaluation of a new protocol for the provisional use of perfusion imaging with exercise stress testing.

PubMed

Duvall, W Lane; Savino, John A; Levine, Elliot J; Hermann, Luke K; Croft, Lori B; Henzlova, Milena J

2015-02-01

Previous literature suggests that myocardial perfusion imaging (MPI) adds little to the prognosis of patients who exercise >10 metabolic equivalents (METs) during stress testing. With this in mind, we prospectively tested a provisional injection protocol in emergency department (ED) patients presenting for the evaluation of chest pain in which a patient would not receive an injection of radioisotope if adequate exercise was achieved without symptoms and a negative ECG response. All patients who presented to the ED over a 5-year period who were referred for stress testing as part of their ED evaluation were included. Patients considered for a provisional protocol were: exercise stress, age <65 years, no known coronary artery disease, and an interpretable rest ECG. Criteria for not injecting included a maximal predicted heart rate ≥85%, ≥10 METs of exercise, no anginal symptoms during stress, and no ECG changes. Groups were compared based on stress test results, all-cause and cardiac mortality, follow-up cardiac testing, subsequent revascularization, and cost. A total of 965 patients were eligible with 192 undergoing exercise-only and 773 having perfusion imaging. After 41.6 ± 19.6 months of follow-up, all-cause mortality was similar in the exercise-only versus the exercise plus imaging group (2.6% vs. 2.1%, p = 0.59). There were no cardiac deaths in the exercise-only group. At 1 year there was no difference in the number of repeat functional stress tests (1.6% vs. 2.1%, p = 0.43), fewer angiograms (0% vs. 4.0%, p = 0.002), and a significantly lower cost ($65 ± $332 vs $506 ± $1,991, p = 0.002; values are in US dollars) in the exercise-only group. The radiation exposure in the exercise plus imaging group was 8.4 ± 2.1 mSv. A provisional injection protocol has a very low mortality, few follow-up diagnostic tests, and lower cost compared to standard imaging protocols. If adopted it would decrease radiation exposure, save time and decrease health-care costs without jeopardizing prognosis.

Emergency department patient compliance with follow-up for outpatient exercise stress testing: a randomized controlled trial.

PubMed

Richards, Doug; Meshkat, Nazanin; Chu, Jaqueline; Eva, Kevin; Worster, Andrew

2007-11-01

Numerous patients are assessed in the emergency department (ED) for chest pain suggestive of acute coronary syndrome (ACS) and subsequently discharged if found to be at low risk. Exercise stress testing is frequently advised as a follow-up investigation for low-risk patients; however, compliance with such recommendations is poorly understood. We sought to determine if compliance with follow-up for exercise stress testing is higher in patients for whom the investigation is ordered at the time of ED discharge, compared with patients who are advised to arrange testing through their family physician (FP). Low-risk chest pain patients being discharged from the ED for outpatient exercise stress test and FP follow-up were randomized into 2 groups. ED staff ordered an exercise stress test for the intervention group, and the control group was advised to contact their FP to arrange testing. The primary outcome was completion of an exercise stress test at 30 days, confirmed through both patient contact and stress test results. Patients were unaware that our primary interest was their compliance with the exercise stress testing recommendations. Two-hundred and thirty-one patients were enrolled and baseline characteristics were similar between the 2 groups. Completion of an exercise stress test at 30 days occurred in 87 out of 120 (72.5%) patients in the intervention group and 60 out of 107 (56.1%) patients in the control group. The difference in compliance rates (16.4%) between the 2 groups was statistically significant (Chi(2) = 6.69, p < 0.001) with a relative risk of 1.29 (95% confidence interval 1.18-1.40), and the results remained significant after a "worst case" sensitivity analysis involving 4 control group cases lost to follow-up. When subjects were contacted by telephone 30 days after the ED visit, 60% of those who were noncompliant patients felt they did not have a heart problem and that further testing was unnecessary. When ED staff order an outpatient exercise stress test following investigation for potential ACS, patients are more likely to complete the test if it is booked for them before ED discharge. After discharge, many low-risk chest pain patients feel they are not at risk and do not return to their FP for further testing in a timely manner as advised. Changing to a strategy of ED booking of exercise stress testing may help earlier identification of patients with coronary heart disease.

Health-related variables and predictors of Health-promoting Lifestyle in cardiovascular disease patients.

PubMed

Mohsenipouya, Hossein; Majlessi, Fereshteh; Shojaeizadeh, Davood; Foroushani, Abbas Rahimi; Ghafari, Rahman; Habibi, Vali; Makrani, Azam Seyfi

2016-04-01

The principal cause for death in the world is cardiovascular disease. Poor lifestyle is a contributing element in this regard. The objective of this study was to estimate the effects of health-related variables and lifestyle variables on the results of exercise stress tests in patients with cardiovascular disease in Iran. The study population in this case-control study was 220 patients who were candidates for exercise stress tests in Mazandaran Province (Iran) in 2015. The patients were divided randomly into two groups based on the results of their exercise stress tests, i.e., positive (110 patients) and negative (110 patients). The data collection tool was a standard questionnaire entitled "Health promotion lifestyle profile-II." The data were analyzed using mean, standard deviation, the chi-squared test, and logistic regression by SPSS version 22 software. The risk of a positive exercise stress test increases with age. The age group above 65 was 1.049 times more at risk of a positive exercise stress test than the age group of less than 45. The people with dyslipidemia had 1.635 times greater risk of positive exercise stress tests than the group without dyslipidemia. In addition, patients with hypertension had 1.579 times greater risk of positive exercise stress tests than the group without hypertension. The lack of individual health responsibility (Odds ratio (OR): 1.622), stress management (OR: 1.592), and physical activity (OR: 1.245) contributed more to positive exercise tests than the other risk factors. Educational interventions can improve the responsibility for health, physical activity, and stress management among people with the risk of cardiovascular disease.

Understanding the meaning of lactate threshold in resistance exercises.

PubMed

Garnacho-Castaño, M V; Dominguez, R; Maté-Muñoz, J L

2015-05-01

This study compares acute cardiorespiratory, metabolic, mechanical and rating of perceived effort (RPE) responses to 2 different prolonged constant-load exercises, half-squat (HS) and cycle ergometry, performed at a workload corresponding to the lactate threshold (LT). A total of 18 healthy subjects completed 5 exercise tests separated by 48 h rest periods: an incremental cycle ergometer test, a constant-load cycle ergometer test at LT intensity, a one-repetition maximum (1RM) HS test, an incremental HS test and a constant-load HS test at LT intensity. In both constant-load tests, cardiorespiratory, metabolic and RPE data were recorded. Mechanical responses before and after each test were assessed in terms of jump height and mean power measured in a counter movement jump (CMJ) test. In both exercises, cardiorespiratory and metabolic responses stabilized, though cardiorespiratory responses were significantly greater for cycle ergometry (P<0.001), with the exception of respiratory exchange ratio (RER), which was higher for HS (P=0.028). Mechanical fatigue was observed in only HS (P<0.001). In conclusion, different exercise modalities induced different yet stable acute cardiorespiratory and metabolic responses. Although such responses were significantly reduced in HS, greater mechanical fatigue was produced, most likely because of the particular muscle actions involved in this form of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations

NASA Technical Reports Server (NTRS)

Bungo, M. W.; Leland, O. S., Jr.

1983-01-01

Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary artery disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with thallium-201 followed by coronary angiography. Results showed that in nearly half of the patients (47%) these tests were in agreement, while either exercise thallium or ETT was positive in 94% of patients with coronary artery disease. It was found that agreement between exercise thallium and ETT tests predicted disease in 92% of the instances or excluded disease in 82% of the instances. It is concluded that despite frequent discord between these two tests in 53% of the cases, a significant gain in exclusive diagnostic capability is realized when applied to a patient population anticipated to have a disease prevalence equal to the 67% encountered in this study.

Overcoming barriers to exercise among parents: A social cognitive theory perspective

PubMed Central

Mailey, Emily L.; Phillips, Siobhan M.; Dlugonski, Deirdre; Conroy, David E.

2017-01-01

Parents face numerous barriers to exercise and exhibit high levels of inactivity. Examining theory-based determinants of exercise among parents may inform interventions for this population. The purpose of this study was to test a social-cognitive model of parental exercise participation over a 12-month period. Mothers (n=226) and fathers (n=70) of children <16 completed measures of exercise, barriers self-efficacy, perceived barriers, and exercise planning at baseline and one year later. Panel analyses were used to test the hypothesized relationships. Barriers self-efficacy was related to exercise directly and indirectly through perceived barriers and prioritization/planning. Prioritization and planning also mediated the relationship between perceived barriers and exercise. These paths remained significant at 12 months. These results suggest efforts to increase exercise in parents should focus on improving confidence to overcome exercise barriers, reducing perceptions of barriers, and helping parents make specific plans for prioritizing and engaging in exercise. PMID:27108160

Exercise deprivation increases negative mood in exercise-addicted subjects and modifies their biochemical markers.

PubMed

Antunes, Hanna Karen Moreira; Leite, Geovana Silva Fogaça; Lee, Kil Sun; Barreto, Amaury Tavares; Santos, Ronaldo Vagner Thomatieli Dos; Souza, Helton de Sá; Tufik, Sergio; de Mello, Marco Tulio

2016-03-15

The aim of this study was to identify the possible association between biochemical markers of exercise addiction and affective parameters in a sample of athletes during 2weeks of withdrawal exercise. Eighteen male runners were distributed into a control group (n=10) composed of runners without exercise addiction symptoms and an exercise addiction group (n=8) composed of runners with exercise addiction symptoms. The volunteers performed a baseline evaluation that included affective questionnaires, blood samples, body composition and an aerobic test performed at ventilatory threshold I. After the baseline evaluation, the groups started an exercise withdrawal period that was sustained for 2weeks. During exercise withdrawal, an actigraph accelerometer was used to monitor the movement index, and CK and LDH were measured in blood samples to validate the non-exercise practice. At the end of the exercise withdrawal period, a blood collection, aerobic test and mood scale was performed in the re-test. The results showed that at the end of the experimental protocol, when compared with the control group, the exercise addiction group showed an increase in depression, confusion, anger, fatigue and decreased vigor mood that improved post-exercise, along with low levels of anandamide at all time-points evaluated and a modest increase in β-endorphin post-exercise. Moreover, the exercise addiction group showed a decrease in oxygen consumption and respiratory exchange ratio after the exercise withdrawal period, which characterized a detraining phenomenon. Our data suggest that a 2-week withdrawal exercise period resulted in an increase of negative mood in exercise addiction; additionally, exercise addiction showed low levels of anandamide. Copyright © 2016 Elsevier Inc. All rights reserved.

The Effect of Estrogen Usage on Eccentric Exercise-Induced Damage in Rat Testes

PubMed Central

Can, Serpil; Selli, Jale; Buyuk, Basak; Aydin, Sergulen; Kocaaslan, Ramazan; Guvendi, Gulname Findik

2015-01-01

Background: Recent years, lots of scientific studies are focused on the possible mechanism of inflammatory response and oxidative stress which are the mechanism related with tissue damage and exercise fatigue. It is well-known that free oxygen radicals may be induced under invitro conditions as well as oxidative stress by exhaustive physical exercise. Objectives: The aim of this study was to investigate the effects of anabolic steroids in conjunction with exercise in the process of spermatogenesis in the testes, using histological and stereological methods. Materials and Methods: Thirty-six male Sprague Dawley rats were divided to six groups, including the control group, the eccentric exercise administered group, the estrogen applied group, the estrogen applied and dissected one hour after eccentric exercise group, the no estrogen applied and dissected 48 hours after eccentric exercise group and the estrogen applied and dissected 48 hours after eccentric exercise group. Eccentric exercise was performed on a motorized rodent treadmill and the estrogen applied groups received daily physiological doses by subcutaneous injections. Testicular tissues were examined using specific histopathological, immunohistochemical and stereological methods. Sections of the testes tissue were stained using the TUNEL method to identify apoptotic cells. Apoptosis was calculated as the percentage of positive cells, using stereological analysis. A statistical analysis of the data was carried out with one-way analysis of variance (ANOVA) for the data obtained from stereological analysis. Results: Conventional light microscopic results revealed that testes tissues of the eccentric exercise administered group and the estrogen supplemented group exhibited slight impairment. In groups that were both eccentrically exercised and estrogen supplemented, more deterioration was detected in testes tissues. Likewise, immunohistochemistry findings were also more prominent in the eccentrically exercised and estrogen supplemented groups. Conclusions: The findings suggest that estrogen supplementation increases damage in testicular tissue due to eccentric exercise. PMID:26023337

Subjective Measures of Exercise Intensity to Gauge Substrate Partitioning in Persons With Paraplegia

PubMed Central

Kressler, Jochen; Cowan, Rachel E.; Ginnity, Kelly; Nash, Mark S.

2012-01-01

Background: The Borg Rating of Perceived Exertion (RPE) Scale and talk test (TT) are commonly recommended for persons to gauge exercise intensity. It is not known whether they are suitable to estimate substrate partitioning between carbohydrate and fat in persons with SCI. Objective: Investigate substrate partitioning/utilization patterns associated with RPE and TT. Methods: Twelve participants with chronic paraplegia underwent 2 arm crank exercise tests on nonconsecutive days within 2 weeks. Test 1 was a graded exercise test (GXT) to volitional exhaustion. Test 2 was a 15-minute self-selected steady state (SS) voluntary arm exercise bout simulating a brief, yet typical exercise session. Results: For the GXT, very light intensity exercise (RPE < 9) and TT stage before last positive were associated with highest contribution of fat oxidation (~35%-50%) to total energy expenditure (TEE). Fat oxidation was low at all stages, with the highest rate (0.13 ± 0.07 g/min) occurring at stage 1 (10 W). Corresponding average RPE was 7 ± 2 and the TT was positive for all participants at this stage. For the SS, fuel partitioning throughout exercise was dominated by carbohydrate oxidation (1.47 ± 0.08 g/min), accounting for almost all (~94%) of TEE with only a minute contribution from fat oxidation (0.02 ± 0.004 g/min). A positive TT was associated with an average contribution of fat oxidation of ~10%. Conclusions: RPE but not the TT appears suitable to predict exercise intensities associated with the highest levels of fat oxidation. However, such intensities are below authoritative intensity thresholds for cardiorespiratory fitness promotion, and therefore the applicability of such a prediction for exercise prescriptions is likely limited to individuals with low exercise tolerance. PMID:23459243

Reconstructing the Jurassic Talkeetna Intra-oceanic Arc of Alaska Using Thermobarometry

NASA Astrophysics Data System (ADS)

Hacker, B. R.; Mehl, L.; Kelemen, P. B.; Rioux, M.; Greene, A.

2005-12-01

The Talkeetna arc is one of two intra-oceanic arcs where the entire section from the upper mantle tectonite through the sediments capping the volcanic carapace is well exposed. The objective of this study is to reconstruct the vertical section of the Talkeetna arc by determining the (re) crystallization pressures at various structural levels. This information is crucial if the Talkeetna arc is to be exploited as an archetypal cross section for purposes as diverse as understanding the evolution of the Earth's crust, assessing rates and mechanisms of arc growth, and understanding the tectonic history arcs in general. The base of the arc crust exposed at Bernard and Scarp Mtns includes rare gabbro(norites) with metamorphic garnets-mineral assemblages excellent for thermobarometry. Broad core-to-rim garnet zoning toward lower Mg#, pyroxenes with near-rim, steep increases in Mg# and Al2O3, and unzoned plagioclase document cooling following core crystallization at ~900- 1025 °C and 0.9-1.0 GPa. Hornblende gabbros with magmatic garnet exposed in the Klanelneechena klippe indicate significantly lower P-T of ~700-835°C, 0.69- 0.77 GPa. Hornblende gabbro (norites) that comprise the bulk of the arc were studied in the Tazlina, Barnette, Scarp, and Pippin Ridge sections. Differences in mineral composition indicate qualitatively that the Tazlina, Barnette, and Scarp sections crystallized at successively greater depths. Temperature was calculated using hbl- plg [Holland and Blundy, 1994] and cpx-opx [QUILF; Andersen et al., 1993] net- transfer equilibria, and P was constrained using high δV/δS equilibria among plg, amph, opx, and cpx. Poorly known amphibole and pyroxene Tschermak-component activity models yield large uncertainties for P, but relative P differences can be anchored to the better-determined garnet gabbro P's, revealing that the rocks from the Barnette Creek section crystallized at ~0.40-0.55 GPa and the Tazlina and Pippin sections formed at ~0.25-0.35 GPa. Al-in-hornblende barometry indicates 0.23 GPa for granodiorites intruding the volcanic section. Calc-silicate rocks within the arc include metasedimentary wall rocks and carbonate veins cutting igneous rock. Grossular-andradite + diopside + calcite +/- sphene + quartz +/- wollastonite +/- scapolite mineral assemblages were strongly overprinted by a prehnite-pumpellyite facies alteration that includes datolite. Calculating P-T for the calc-silicate rocks is tenuous for several reasons-including large calculated Fe3+ in garnet and cpx, complete replacement of plagioclase, extreme partitioning of Mg into cpx, and ill-constrained aCO2--but a general correspondence between P-T inferred for the calc-silicate rocks and nearby metamafic rocks suggests that the calc-silicate assemblages grew during the magmatic development of the arc. Metamorphic rocks in float of the McHugh Complex(?) structurally beneath the Klanelneechena Klippe contain a strong amphibolite-facies fabric formed at 500°C and 1.0 ± 0.1 GPa. In summary, the granodiorites intruded at c. 6-10 km into a volcanic section estimated from stratigraphy to be 7 km thick [Clift et al., 2005]. The shallowest, Tazlina and Pippin, gabbros cooled at ~9-12 km; the Barnette section at ~14-19 km; the Klanelneechena klippe at ~24-26 km; and the base of the arc at ~30-34 km depth. Thus, the arc consists of a volcanic:plutonic ratio of ~28:72, and the current 5-7 km structural thickness of the plutonic section of the arc is ~20-35% of the original 20-26 km thickness.

An exploration of exercise-induced cognitive enhancement and transfer effects to dietary self-control.

PubMed

Lowe, Cassandra J; Kolev, Dimitar; Hall, Peter A

2016-12-01

The primary objective of this study was to examine the effects of aerobic exercise on executive function, specifically inhibitory control, and the transfer to self-control in the dietary domain. It was hypothesized that exercise would enhance inhibitory control, and that this enhancement would facilitate self-control in a laboratory taste test paradigm. Using a crossover design, 51 participants completed counterbalanced sessions of both moderate exercise (experimental condition) and minimal effort walking (control condition) using a treadmill; the intersession interval was 7days. Prior to each exercise bout participants completed a Stroop task. Following each bout participants completed a second Stoop task, as well as a bogus taste test involving three appetitive calorie dense snack foods and two control foods; the amount of each food type consumed during the taste test was covertly measured. Results revealed that moderate exercise significantly improved performance on the Stroop task, and also reduced food consumption during the taste test for appetitive calorie dense snack foods; there was no exercise effect on control food consumption. Exercise-induced gains in Stroop performance mediated the effects of moderate exercise on appetitive snack food consumption. Together these findings provide evidence that a bout of a moderate aerobic exercise can enhance inhibitory control, and support for cross-domain transfer effects to dietary self-control. Copyright © 2016 Elsevier Inc. All rights reserved.

[Acute physical exercise increases homocysteine concentrations in young trained male subjects].

PubMed

Maroto-Sánchez, Beatriz; Valtueña, Jara; Albers, Ulrike; Benito, Pedro J; González-Gross, Marcela

2013-01-01

High levels of homocysteine (Hcy) have been identified as a cardiovascular risk factor. Regarding physical exercise, the results are contradictory. The aim of this study was to determine the influence of maximal intensity exercise and submaximal constant exercise on total serum homocysteine concentrations (tHcy) and other related parameters. Ten physically active male subjects (mean age: 23.51 ± 1.84), performed two treadmill tests, a maximal test and a stable submaximal test at an intensity of 65% of maximal oxygen uptake (VO2max). Serum concentrations of tHcy, Folate, Vitamin B12 and creatinine were analysed before and after each test. Significant increase in serum tHcy concentrations after the maximal (p < 0.05) and submaximal (p < 0.01) tests were observed. Folate and vitamin B12 concentrations also increased significantly after both tests (p < 0.05). Creatinine levels increased only after the maximal test (p < 0.001). A statistically significant inverse relationship was found between folate and tHcy concentrations (p < 0.05) at all the measurement points. THcy levels increased significantly after acute exercise in both maximum and submaximal intensity exercises. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

Several submaximal exercise tests are reliable, valid and acceptable in people with chronic pain, fibromyalgia or chronic fatigue: a systematic review.

PubMed

Ratter, Julia; Radlinger, Lorenz; Lucas, Cees

2014-09-01

Are submaximal and maximal exercise tests reliable, valid and acceptable in people with chronic pain, fibromyalgia and fatigue disorders? Systematic review of studies of the psychometric properties of exercise tests. People older than 18 years with chronic pain, fibromyalgia and chronic fatigue disorders. Studies of the measurement properties of tests of physical capacity in people with chronic pain, fibromyalgia or chronic fatigue disorders were included. Studies were required to report: reliability coefficients (intraclass correlation coefficient, alpha reliability coefficient, limits of agreements and Bland-Altman plots); validity coefficients (intraclass correlation coefficient, Spearman's correlation, Kendal T coefficient, Pearson's correlation); or dropout rates. Fourteen studies were eligible: none had low risk of bias, 10 had unclear risk of bias and four had high risk of bias. The included studies evaluated: Åstrand test; modified Åstrand test; Lean body mass-based Åstrand test; submaximal bicycle ergometer test following another protocol other than Åstrand test; 2-km walk test; 5-minute, 6-minute and 10-minute walk tests; shuttle walk test; and modified symptom-limited Bruce treadmill test. None of the studies assessed maximal exercise tests. Where they had been tested, reliability and validity were generally high. Dropout rates were generally acceptable. The 2-km walk test was not recommended in fibromyalgia. Moderate evidence was found for reliability, validity and acceptability of submaximal exercise tests in patients with chronic pain, fibromyalgia or chronic fatigue. There is no evidence about maximal exercise tests in patients with chronic pain, fibromyalgia and chronic fatigue. Copyright © 2014. Published by Elsevier B.V.

Formation of redox gradients during magma-magma mixing

NASA Astrophysics Data System (ADS)

Ruprecht, P.; Fiege, A.; Simon, A. C.

2015-12-01

Magma-mixing is a key process that controls mass transfer in magmatic systems. The variations in melt compositions near the magma-magma interface potentially change the Fe oxidation state [1] and, thus, affect the solubility and transport of metals. To test this hypothesis, diffusion-couple experiments were performed at 1000 °C, 150 MPa and QFM+4. Synthesized crystal-bearing cylinders of hydrous dacite and hydrous basaltic andesite were equilibrated for up to 80 h. The run products show that mafic components (Fe, Mg, etc.) were transported from the andesite into the dacite, while Si, Na and K diffused from the dacite into the andesite. A crystal dissolution sequence in the order of cpx, opx, plag, and spl/il was observed for the andesite. We combined μ-XANES spectroscopy at Fe K-edge [2] with two-oxide oxybarometry [3] to measure redox profiles within our experiments. Here, fO2 decreased towards the interface within the dacite and increased towards the interface within the andesite. This discontinuous fO2 evolution, with a sharp redox gradient of ~1.8 log fO2 units at the interface was maintained throughout the time-series despite the externally imposed fO2 of the vessel. We propose a combination of two mechanisms that create and sustain this redox gradient: 1) The dissolution of cpx and opx in the andesite mainly introduced Fe2+ into the melt, which diffused towards the dacite, lowering Fe3+/SFe near the interface. 2) Charge balance calculations in the melt during diffusive exchange suggest net positive charge excess in the andesite near the interface (i.e., oxidation) and net negative charge excess in the dacite near the interface (i.e., reduction). We suggest that this (metastable) redox layer can help to explain the contrasting Au/Cu ratios observed for arc-related porphyry-type ore deposits. [1] Moretti (2005), Ann. Geophys. 48, 583-608. [2] Cottrell et al. (2009), Chem. Geol. 268, 167-179. [3] Ghiorso and Evans (2008), Am. J. Sci. 308, 957-1039.

Evaluation of exercise capacity after severe stroke using robotics-assisted treadmill exercise: a proof-of-concept study.

PubMed

Stoller, O; de Bruin, E D; Schindelholz, M; Schuster, C; de Bie, R A; Hunt, K J

2013-01-01

Robotics-assisted treadmill exercise (RATE) with focus on motor recovery has become popular in early post-stroke rehabilitation but low endurance for exercise is highly prevalent in these individuals. This study aimed to develop an exercise testing method using robotics-assisted treadmill exercise to evaluate aerobic capacity after severe stroke. Constant load testing (CLT) based on body weight support (BWS) control, and incremental exercise testing (IET) based on guidance force (GF) control were implemented during RATE. Analyses focussed on step change, step response kinetics, and peak performance parameters of oxygen uptake. Three subjects with severe motor impairment 16-23 days post-stroke were included. CLT yielded reasonable step change values in oxygen uptake, whereas response kinetics of oxygen uptake showed low goodness of fit. Peak performance parameters were not obtained during IET. Exercise testing in post-stroke individuals with severe motor impairments using a BWS control strategy for CLT is deemed feasible and safe. Our approach yielded reasonable results regarding cardiovascular performance parameters. IET based on GF control does not provoke peak cardiovascular performance due to uncoordinated walking patterns. GF control needs further development to optimally demand active participation during RATE. The findings warrant further research regarding the evaluation of exercise capacity after severe stroke.

Effect of increasing maximal aerobic exercise on serum muscles enzymes in professional field hockey players.

PubMed

Hazar, Muhsin; Otag, Aynur; Otag, Ilhan; Sezen, Mehmet; Sever, Ozan

2014-11-04

Exercise results in oxidative enzyme increase and micro-injuries in skeletal muscles. The aim of this study was to investigate the effect of maximal aerobic exercise on serum muscle enzymes in professional field hockey players. This study aims to determine the effect of increasing maximal aerobic exercise on creatine kinase (CK), creatine kinase-MB (CK-MB), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum levels. 31 young professional field hockey players (13 female and 18 male players) volunteered for this study. All participants underwent the shuttle run test. Blood samples were taken from each participant before the shuttle run test. Post test blood samples were taken immediately after exercise and one hour after respectively. Pre and post test CK, CK-MB, AST and ALT values were measured by means of auto analyzer using original kits. The acute post test measure of the CK level increased in male (p=0.002) and female (p=0.00) sportsmen. CK-MB values obtained one hour after the exercise was lower than those before the exercise in males (p=0.02). In females (p=0.017) and males (p=0.05) AST activity significantly increased immediately after exercise and decreased to resting activity 1 h recovery. ALT significantly increased immediately after exercise in female (p=0.03) and male (p=0.00) athletes and after 1 h recovery ALT activities decreased below resting values. The timing and severity of exercise used in our study increased CK values, decreased CK-MB values and AST, ALT values increased in female and male field hockey players.

Effect of aquatic versus land based exercise programs on physical performance in severely burned patients: a randomized controlled trial.

PubMed

Zoheiry, Ibrahim M; Ashem, Haidy N; Ahmed, Hamada Ahmed Hamada; Abbas, Rami

2017-12-01

[Purpose] To compare the effect of an aquatic-based versus a land-based exercise regimen on the physical performance of severely burned patients. [Subjects and Methods] Forty patients suffering from severe burn (total body surface area more than 30%) were recruited from several outpatient clinics in Greater Cairo. Their ages ranged between 20 to 40 years and were randomly assigned into two equal groups: group (A), which received an aquatic based exercise program, and group (B), which received a land-based exercise program. The exercise program, which took place in 12 consecutive weeks, consisted of flexibility, endurance, and lower and upper body training. Physical performance was assessed using 30 seconds chair stand test, stair climb test, 30 meter fast paced walk test, time up and go test, 6-minute walk test and a VO2max evaluation. [Results] Significantly increase in the 30 second chair stand, 6-minute walk, 30 meter fast paced walk, stair climb, and VO2 max tests and significantly decrease in the time up and go test in group A (aquatic based exercise) compared with group B (a land-based exercise) at the post treatment. [Conclusion] Twelve-week program of an aquatic program yields improvement in both physical performance and VO2 max in patients with severe burns.

Effect of aquatic versus land based exercise programs on physical performance in severely burned patients: a randomized controlled trial

PubMed Central

Zoheiry, Ibrahim M.; Ashem, Haidy N.; Ahmed, Hamada Ahmed Hamada; Abbas, Rami

2017-01-01

[Purpose] To compare the effect of an aquatic-based versus a land-based exercise regimen on the physical performance of severely burned patients. [Subjects and Methods] Forty patients suffering from severe burn (total body surface area more than 30%) were recruited from several outpatient clinics in Greater Cairo. Their ages ranged between 20 to 40 years and were randomly assigned into two equal groups: group (A), which received an aquatic based exercise program, and group (B), which received a land-based exercise program. The exercise program, which took place in 12 consecutive weeks, consisted of flexibility, endurance, and lower and upper body training. Physical performance was assessed using 30 seconds chair stand test, stair climb test, 30 meter fast paced walk test, time up and go test, 6-minute walk test and a VO2max evaluation. [Results] Significantly increase in the 30 second chair stand, 6-minute walk, 30 meter fast paced walk, stair climb, and VO2 max tests and significantly decrease in the time up and go test in group A (aquatic based exercise) compared with group B (a land-based exercise) at the post treatment. [Conclusion] Twelve-week program of an aquatic program yields improvement in both physical performance and VO2 max in patients with severe burns. PMID:29643605

Metabolic control during exercise with and without medium-chain triglycerides (MCT) in children with long-chain 3-hydroxy acyl-CoA dehydrogenase (LCHAD) or trifunctional protein (TFP) deficiency

PubMed Central

Gillingham, Melanie B.; Scott, Bradley; Elliott, Diane; Harding, Cary O.

2009-01-01

Exercise induced rhabdomyolysis is a complication of long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and mitochondrial trifunctional protein (TFP) deficiency that frequently leads to exercise avoidance. Dietary therapy for most subjects includes medium-chain triglyceride (MCT) supplementation but analysis of diet records indicates that the majority of patients consume oral MCT only with breakfast and at bedtime. We hypothesized that MCT immediately prior to exercise would provide an alternative fuel source during that bout of exercise and improve exercise tolerance in children with LCHAD deficiency. Nine subjects completed two 45 min moderate intensity (60–70% predicted maximum heart rate (HR)) treadmill exercise tests. Subjects were given 4 oz of orange juice alone or orange juice and 0.5 g MCT per kg lean body mass, 20 min prior to exercise in a randomized cross-over design. ECG and respiratory gas exchange including respiratory quotient (RQ) were monitored. Blood levels of acylcarnitines, creatine kinase, lactate, and β-hydroxybutyrate were measured prior to and immediately after exercise, and again following 20min rest. Creatine kinase and lactate levels did not change with exercise. There was no significant difference in RQ between the two exercise tests but there was a decrease in steady-state HR following MCT supplementation. Cumulative long-chain 3-hydroxyacylcarnitines were 30% lower and β-hydroxybutyrate was three-fold higher after the MCT-pretreated exercise test compared to the test with orange juice alone. Coordinating MCT supplementation with periods of increased activity may improve the metabolic control of children with LCHAD and TFP deficiency following exercise. PMID:16876451

Control Group Paradigms in Studies Investigating Acute Effects of Exercise on Cognitive Performance-An Experiment on Expectation-Driven Placebo Effects.

PubMed

Oberste, Max; Hartig, Philipp; Bloch, Wilhelm; Elsner, Benjamin; Predel, Hans-Georg; Ernst, Bernhard; Zimmer, Philipp

2017-01-01

Introduction: Many studies report improvements in cognitive performance following acute endurance exercise compared to control group treatment. These cognitive benefits are interpreted as a result of a physiological response to exercise. However, it was also hypothesized that expectation-driven placebo effects account for these positive effects. The purpose of this study was to investigate the differences between expectations for cognitive benefits toward acute endurance exercise and multiple control group treatments. Methods: Healthy individuals ( N = 247, 24.26 ± 3.88 years) were randomized to eight different groups watching videos of a moderate, a vigorous exercise treatment or one control group treatment (waiting, reading, video-watching, stretching, myofascial release workout, and very light exercise). Then, they were introduced to three commonly used cognitive test procedures in acute exercise-cognition research (Stroop-test, Trail-Making-test, Free-recall-task). Participants rated the effect they would expect on their performance in those tasks, if they had received the treatment shortly before the task, on an 11-point Likert scale. Results: No significantly different expectations for cognitive benefits toward acute moderate exercise and control group treatments could be revealed. Participants expected significantly worse performance following vigorous exercise compared to following waiting and stretching for all cognitive tests. Significantly worse performance after vigorous exercise compared to after very light exercise was expected for Stroop and Free-recall. For Free-recall, participants expected worse performance after vigorous exercise compared to myofascial release training as well. Conclusion: Our results indicate that expectation-driven placebo effects are unlikely to cause the reported greater cognitive improvements following acute moderate and vigorous endurance exercise compared to following common control group treatments.

Control Group Paradigms in Studies Investigating Acute Effects of Exercise on Cognitive Performance–An Experiment on Expectation-Driven Placebo Effects

PubMed Central

Oberste, Max; Hartig, Philipp; Bloch, Wilhelm; Elsner, Benjamin; Predel, Hans-Georg; Ernst, Bernhard; Zimmer, Philipp

2017-01-01

Introduction: Many studies report improvements in cognitive performance following acute endurance exercise compared to control group treatment. These cognitive benefits are interpreted as a result of a physiological response to exercise. However, it was also hypothesized that expectation-driven placebo effects account for these positive effects. The purpose of this study was to investigate the differences between expectations for cognitive benefits toward acute endurance exercise and multiple control group treatments. Methods: Healthy individuals (N = 247, 24.26 ± 3.88 years) were randomized to eight different groups watching videos of a moderate, a vigorous exercise treatment or one control group treatment (waiting, reading, video-watching, stretching, myofascial release workout, and very light exercise). Then, they were introduced to three commonly used cognitive test procedures in acute exercise-cognition research (Stroop-test, Trail-Making-test, Free-recall-task). Participants rated the effect they would expect on their performance in those tasks, if they had received the treatment shortly before the task, on an 11-point Likert scale. Results: No significantly different expectations for cognitive benefits toward acute moderate exercise and control group treatments could be revealed. Participants expected significantly worse performance following vigorous exercise compared to following waiting and stretching for all cognitive tests. Significantly worse performance after vigorous exercise compared to after very light exercise was expected for Stroop and Free-recall. For Free-recall, participants expected worse performance after vigorous exercise compared to myofascial release training as well. Conclusion: Our results indicate that expectation-driven placebo effects are unlikely to cause the reported greater cognitive improvements following acute moderate and vigorous endurance exercise compared to following common control group treatments. PMID:29276483

Pulmonary arterial pressure detects functional mitral stenosis after annuloplasty for primary mitral regurgitation: An exercise stress echocardiographic study.

PubMed

Samiei, Niloufar; Tajmirriahi, Marzieh; Rafati, Ali; Pasebani, Yeganeh; Rezaei, Yousef; Hosseini, Saeid

2018-02-01

The restrictive mitral valve annuloplasty (RMA) is the treatment of choice for degenerative mitral regurgitation (MR), but postoperative functional mitral stenosis remains a matter of debate. In this study, we sought to determine the impact of mitral stenosis on the functional capacity of patients. In a cross-sectional study, 32 patients with degenerative MR who underwent RMA using a complete ring were evaluated. All participants performed treadmill exercise test and underwent echocardiographic examinations before and after exercise. The patients' mean age was 50.1 ± 12.5 years. After a mean follow-up of 14.1 ± 5.9 months (6-32 months), the number of patients with a mitral valve peak gradient >7.5 mm Hg, a mitral valve mean gradient >3 mm Hg, and a pulmonary arterial pressure (PAP) ≥25 mm Hg at rest were 50%, 40.6%, and 62.5%, respectively. 13 patients (40.6%) had incomplete treadmill exercise test. All hemodynamic parameters were higher at peak exercise compared with at rest levels (all P < .05). The PAP at rest and at peak exercise as well as peak transmitral gradient at peak exercise were higher in patients with incomplete exercise compared with complete exercise test (all P < .05). The PAP at rest (a sensitivity and a specificity of 84.6% and 52.6%, respectively; area under the curve [AUC] = .755) and at peak exercise (a sensitivity and a specificity of 100% and 47.4%, respectively; AUC = .755) discriminated incomplete exercise test. The RMA for degenerative MR was associated with a functional stenosis and the PAP at rest and at peak exercise discriminated low exercise capacity. © 2017, Wiley Periodicals, Inc.

Warm-ups for military fitness testing: rapid evidence assessment of the literature.

PubMed

Zeno, Stacey A; Purvis, Dianna; Crawford, Cindy; Lee, Courtney; Lisman, Peter; Deuster, Patricia A

2013-07-01

Warm-up exercises are commonly used before exercise as a method to physiologically prepare for strenuous physical activity. Various warm-up exercises are often implemented but without scientific merit and, at times, may be detrimental to performance. To date, no systematic reviews have examined the effectiveness of warm-up exercises for military physical fitness test (PFT) or combat fitness test (CFT). The purpose of this rapid evidence assessment of the literature was to examine the quantity, quality, and effectiveness of warm-up exercises for PFT and identify those that might increase PFT and/or CFT scores, as reported in the literature. Literature searches of randomized controlled trials were performed across various databases from database inception to May 2011. Methodological quality of included studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) 50 criteria for randomized controlled trial designs, and studies were individually described. Subject matter experts summarized the results applicable or generalizable to military testing. The search yielded a total of 1177 citations, with 37 fitting our inclusion criteria. Cardiovascular warm-ups increased sprint/running time, but dynamic stretching and dynamic warm-ups had the most positive outcome for the various exercise tests examined. Systematically, static stretching had no beneficial or detrimental effect on exercise performance but did improve range of movement exercises. Selected warm-up exercise may increase PFT and possibly CFT scores. Further research is needed to investigate the efficacy of dynamic stretching and dynamic warm-ups.

Eucapnic voluntary hyperventilation in diagnosing exercise-induced laryngeal obstructions.

PubMed

Christensen, Pernille M; Rasmussen, Niels

2013-11-01

Exercise-induced laryngeal obstructions (EILOs) cause exercise-related respiratory symptoms (ERRS) and are important differential diagnoses to exercise-induced asthma. The diagnostic method for EILOs includes provocation to induce the obstruction followed by a verification of the obstruction and the degree thereof. The objective of the present study was to examine if a eucapnic voluntary hyperventilation (EVH) test could induce laryngeal obstructions laryngoscopically identical in subtypes and development as seen during an exercise test. EVH and exercise testing with continuous laryngoscopy were performed during a screening of two national athletic teams (n = 67). The laryngoscopic recordings were examined for usability, abnormalities and maximal supraglottic and glottic obstruction using two currently available methods (Eilomea and CLE-score). The participants were asked questions on ERRS, and whether the symptoms experienced during each provocation matched those experienced during regular training. A total of 39 completed both tests. There were no significant differences in subtypes and development thereof, the experience of symptoms, and specificity and sensitivity between the methods. Significantly more recordings obtained during the exercise test were usable for evaluation primarily due to resilient mucus on the tip of the fiber-laryngoscope in the EVH test. Only recordings of six athletes from both provocation methods were usable for evaluation using the Eilomea method (high-quality demand). Amongst these, a linear correlation was found for the glottic obstruction. EVH tests can induce EILOs. However, the present test protocol needs adjustments to secure better visualisation of the larynx during provocation.

Translation of incremental talk test responses to steady-state exercise training intensity.

PubMed

Lyon, Ellen; Menke, Miranda; Foster, Carl; Porcari, John P; Gibson, Mark; Bubbers, Terresa

2014-01-01

The Talk Test (TT) is a submaximal, incremental exercise test that has been shown to be useful in prescribing exercise training intensity. It is based on a subject's ability to speak comfortably during exercise. This study defined the amount of reduction in absolute workload intensity from an incremental exercise test using the TT to give appropriate absolute training intensity for cardiac rehabilitation patients. Patients in an outpatient rehabilitation program (N = 30) performed an incremental exercise test with the TT given every 2-minute stage. Patients rated their speech comfort after reciting a standardized paragraph. Anything other than a "yes" response was considered the "equivocal" stage, while all preceding stages were "positive" stages. The last stage with the unequivocally positive ability to speak was the Last Positive (LP), and the preceding stages were (LP-1 and LP-2). Subsequently, three 20-minute steady-state training bouts were performed in random order at the absolute workload at the LP, LP-1, and LP-2 stages of the incremental test. Speech comfort, heart rate (HR), and rating of perceived exertion (RPE) were recorded every 5 minutes. The 20-minute exercise training bout was completed fully by LP (n = 19), LP-1 (n = 28), and LP-2 (n = 30). Heart rate, RPE, and speech comfort were similar through the LP-1 and LP-2 tests, but the LP stage was markedly more difficult. Steady-state exercise training intensity was easily and appropriately prescribed at intensity associated with the LP-1 and LP-2 stages of the TT. The LP stage may be too difficult for patients in a cardiac rehabilitation program.

Evaluation of the Compulsive Exercise Test (CET) in Adolescents with Eating Disorders: Factor Structure and Relation to Eating Disordered Psychopathology.

PubMed

Swenne, Ingemar

2016-07-01

The aims of this study were to explore the factor structure of the Compulsive Exercise Test (CET) in a clinical sample of Swedish adolescents with eating disorders (ED) and to study the relationship of CET with ED cognitions, body weight and exercise frequency. The compulsive Exercise Test, the Eating Disorders Examination-Questionnaire, body mass index (BMI) and exercise frequency were available at assessment of 210 adolescents (age 14.4 ± 1.6 years) with ED. Factor analysis generated four factors with close similarity to factors previously obtained in a community sample of adolescents samples and supported the use of the original version of CET. Exercise for weight control was strongly related to ED cognitions but less to exercise frequency and BMI. Exercise for regulation of mood was related to ED cognitions and exercise frequency but not to BMI. In adolescents with ED, different aspects of exercise are related to ED cognitions. This needs addressing in the treatment of adolescents with ED. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.

Perioperative cardiopulmonary exercise testing (CPET): consensus clinical guidelines on indications, organization, conduct, and physiological interpretation.

PubMed

Levett, D Z H; Jack, S; Swart, M; Carlisle, J; Wilson, J; Snowden, C; Riley, M; Danjoux, G; Ward, S A; Older, P; Grocott, M P W

2018-03-01

The use of perioperative cardiopulmonary exercise testing (CPET) to evaluate the risk of adverse perioperative events and inform the perioperative management of patients undergoing surgery has increased over the last decade. CPET provides an objective assessment of exercise capacity preoperatively and identifies the causes of exercise limitation. This information may be used to assist clinicians and patients in decisions about the most appropriate surgical and non-surgical management during the perioperative period. Information gained from CPET can be used to estimate the likelihood of perioperative morbidity and mortality, to inform the processes of multidisciplinary collaborative decision making and consent, to triage patients for perioperative care (ward vs critical care), to direct preoperative interventions and optimization, to identify new comorbidities, to evaluate the effects of neoadjuvant cancer therapies, to guide prehabilitation and rehabilitation, and to guide intraoperative anaesthetic practice. With the rapid uptake of CPET, standardization is key to ensure valid, reproducible results that can inform clinical decision making. Recently, an international Perioperative Exercise Testing and Training Society has been established (POETTS www.poetts.co.uk) promoting the highest standards of care for patients undergoing exercise testing, training, or both in the perioperative setting. These clinical cardiopulmonary exercise testing guidelines have been developed by consensus by the Perioperative Exercise Testing and Training Society after systematic literature review. The guidelines have been endorsed by the Association of Respiratory Technology and Physiology (ARTP). Copyright © 2017. Published by Elsevier Ltd.

Controversies in the physiological basis of the 'anaerobic threshold' and their implications for clinical cardiopulmonary exercise testing.

PubMed

Hopker, J G; Jobson, S A; Pandit, J J

2011-02-01

This article reviews the notion of the 'anaerobic threshold' in the context of cardiopulmonary exercise testing. Primarily, this is a review of the proposed mechanisms underlying the ventilatory and lactate response to incremental exercise, which is important to the clinical interpretation of an exercise test. Since such tests are often conducted for risk stratification before major surgery, a failure to locate or justify the existence of an anaerobic threshold will have some implications for clinical practice. We also consider alternative endpoints within the exercise response that might be better used to indicate a patient's capacity to cope with the metabolic demands encountered both during and following major surgery. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

[A school-level longitudinal study of clinical performance examination scores].

PubMed

Park, Jang Hee

2015-06-01

This school-level longitudinal study examined 7 years of clinical performance data to determine differences (effects) in students and annual changes within a school and between schools; examine how much their predictors (characteristics) influenced the variation in student performance; and calculate estimates of the schools' initial status and growth. A school-level longitudinal model was tested: level 1 (between students), level 2 (annual change within a school), and level 3 (between schools). The study sample comprised students who belonged to the CPX Consortium (n=5,283 for 2005~2008 and n=4,337 for 2009~2011). Despite a difference between evaluation domains, the performance outcomes were related to individual large-effect differences and small-effect school-level differences. Physical examination, clinical courtesy, and patient education were strongly influenced by the school effect, whereas patient-physician interaction was not affected much. Student scores are influenced by the school effect (differences), and the predictors explain the variation in differences, depending on the evaluation domain.

Diagnostic characteristics and prognoses of primary-care patients referred for clinical exercise testing: a prospective observational study.

PubMed

Nilsson, Gunnar; Mooe, Thomas; Stenlund, Hans; Samuelsson, Eva

2014-04-18

Evaluation of angina symptoms in primary care often includes clinical exercise testing. We sought to identify clinical characteristics that predicted the outcome of exercise testing and to describe the occurrence of cardiovascular events during follow-up. This study followed patients referred to exercise testing for suspected coronary disease by general practitioners in the County of Jämtland, Sweden (enrolment, 25 months from February 2010). Patient characteristics were registered by pre-test questionnaire. Exercise tests were performed with a bicycle ergometer, a 12-lead electrocardiogram, and validated scales for scoring angina symptoms. Exercise tests were classified as positive (ST-segment depression >1 mm and chest pain indicative of angina), non-conclusive (ST depression or chest pain), or negative. Odds ratios (ORs) for exercise-test outcome were calculated with a bivariate logistic model adjusted for age, sex, systolic blood pressure, and previous cardiovascular events. Cardiovascular events (unstable angina, myocardial infarctions, decisions on revascularization, cardiovascular death, and recurrent angina in primary care) were recorded within six months. A probability cut-off of 10% was used to detect cardiovascular events in relation to the predicted test outcome. We enrolled 865 patients (mean age 63.5 years, 50.6% men); 6.4% of patients had a positive test, 75.5% were negative, 16.4% were non-conclusive, and 1.7% were not assessable. Positive or non-conclusive test results were predicted by exertional chest pain (OR 2.46, 95% confidence interval (CI) 1.69-3.59), a pathologic ST-T segment on resting electrocardiogram (OR 2.29, 95% CI 1.44-3.63), angina according to the patient (OR 1.70, 95% CI 1.13-2.55), and medication for dyslipidaemia (OR 1.51, 95% CI 1.02-2.23). During follow-up, cardiovascular events occurred in 8% of all patients and 4% were referred to revascularization. Cardiovascular events occurred in 52.7%, 18.3%, and 2% of patients with positive, non-conclusive, or negative tests, respectively. The model predicted 67/69 patients with a cardiovascular event. Clinical characteristics can be used to predict exercise test outcome. Primary care patients with a negative exercise test have a very low risk of cardiovascular events, within six months. A predictive model based on clinical characteristics can be used to refine the identification of low-risk patients.

Kinematic effect of Nintendo WiiTM sports program exercise on obstacle gait in elderly women with falling risk

PubMed Central

Jung, Dae-In; Ko, Dae-Sik; Jeong, Mi-Ae

2015-01-01

[Purpose] This study evaluated the changes in balance ability and obstacle gait after lumbar stabilization exercise and Nintendo WiiTM Sports in elderly at risk for falls. [Subjects and Methods] Twenty-four elderly women with at risk for falls were randomly divided into the control, lumbar stabilization exercise, and Nintendo Wii Sports groups. Static balance was measured by the Berg Balance Scale and functional reach test, dynamic balance by the timed up-and-go test, and obstacle negotiation function by crossing velocity and maximum vertical heel clearance. [Results] Both the lumbar stabilization exercise and Nintendo Wii Sports groups showed significant improvements in obstacle negotiation function after the exercise compared to the control group. Berg Balance Scale and functional reach test scores were greater in the lumbar stabilization exercise group, while the timed up-and-go test time was significantly better in the Nintendo Wii Sports groups. [Conclusion] Lumbar stabilization exercises and Nintendo Wii Sports improve falling related balance and obstacle negotiation function in elderly women at risk for falls. PMID:26157228

Kinematic effect of Nintendo Wii(TM) sports program exercise on obstacle gait in elderly women with falling risk.

PubMed

Jung, Dae-In; Ko, Dae-Sik; Jeong, Mi-Ae

2015-05-01

[Purpose] This study evaluated the changes in balance ability and obstacle gait after lumbar stabilization exercise and Nintendo Wii(TM) Sports in elderly at risk for falls. [Subjects and Methods] Twenty-four elderly women with at risk for falls were randomly divided into the control, lumbar stabilization exercise, and Nintendo Wii Sports groups. Static balance was measured by the Berg Balance Scale and functional reach test, dynamic balance by the timed up-and-go test, and obstacle negotiation function by crossing velocity and maximum vertical heel clearance. [Results] Both the lumbar stabilization exercise and Nintendo Wii Sports groups showed significant improvements in obstacle negotiation function after the exercise compared to the control group. Berg Balance Scale and functional reach test scores were greater in the lumbar stabilization exercise group, while the timed up-and-go test time was significantly better in the Nintendo Wii Sports groups. [Conclusion] Lumbar stabilization exercises and Nintendo Wii Sports improve falling related balance and obstacle negotiation function in elderly women at risk for falls.

Meeting Unmanned Air Vehicle Platform Challenges Using Oblique Wing Aircraft

DTIC Science & Technology

2007-11-01

effects need to be assessed with fully relaxed wakes (Section 5). 4.2 Oblique Flying Wing with 75o Folded Tip / Winglet , Mach 0.8, CL = 0.3 Fig.9 (a...e) refers to an OFW flying at 30o sweep with 75o folded tip or winglet , Ref.14. This also acts as a vertical fin or as a control (deflection...design problem. The resultant Cp-x distributions (e) at the design condition are well behaved. The distributions on the winglet are slightly more

Could the two-minute step test be an alternative to the six-minute walk test for patients with systolic heart failure?

PubMed

Węgrzynowska-Teodorczyk, Kinga; Mozdzanowska, Dagmara; Josiak, Krystian; Siennicka, Agnieszka; Nowakowska, Katarzyna; Banasiak, Waldemar; Jankowska, Ewa A; Ponikowski, Piotr; Woźniewski, Marek

2016-08-01

The consequence of exercise intolerance for patients with heart failure is the difficulty climbing stairs. The two-minute step test is a test that reflects the activity of climbing stairs. The aim of the study design is to evaluate the applicability of the two-minute step test in an assessment of exercise tolerance in patients with heart failure and the association between the six-minute walk test and the two-minute step test. Participants in this study were 168 men with systolic heart failure (New York Heart Association (NYHA) class I-IV). In the study we used the two-minute step test, the six-minute walk test, the cardiopulmonary exercise test and isometric dynamometer armchair. Patients who performed more steps during the two-minute step test covered a longer distance during the six-minute walk test (r = 0.45). The quadriceps strength was correlated with the two-minute step test and the six-minute walk test (r = 0.61 and r = 0.48). The greater number of steps performed during the two-minute step test was associated with higher values of peak oxygen consumption (r = 0.33), ventilatory response to exercise slope (r = -0.17) and longer time of exercise during the cardiopulmonary exercise test (r = 0.34). Fatigue and leg fatigue were greater after the two-minute step test than the six-minute walk test whereas dyspnoea and blood pressure responses were similar. The two-minute step test is well tolerated by patients with heart failure and may thus be considered as an alternative for the six-minute walk test. © The European Society of Cardiology 2016.

Using implicit attitudes of exercise importance to predict explicit exercise dependence symptoms and exercise behaviors.

PubMed

Forrest, Lauren N; Smith, April R; Fussner, Lauren M; Dodd, Dorian R; Clerkin, Elise M

2016-01-01

"Fast" (i.e., implicit) processing is relatively automatic; "slow" (i.e., explicit) processing is relatively controlled and can override automatic processing. These different processing types often produce different responses that uniquely predict behaviors. In the present study, we tested if explicit, self-reported symptoms of exercise dependence and an implicit association of exercise as important predicted exercise behaviors and change in problematic exercise attitudes. We assessed implicit attitudes of exercise importance and self-reported symptoms of exercise dependence at Time 1. Participants reported daily exercise behaviors for approximately one month, and then completed a Time 2 assessment of self-reported exercise dependence symptoms. Undergraduate males and females (Time 1, N = 93; Time 2, N = 74) tracked daily exercise behaviors for one month and completed an Implicit Association Test assessing implicit exercise importance and subscales of the Exercise Dependence Questionnaire (EDQ) assessing exercise dependence symptoms. Implicit attitudes of exercise importance and Time 1 EDQ scores predicted Time 2 EDQ scores. Further, implicit exercise importance and Time 1 EDQ scores predicted daily exercise intensity while Time 1 EDQ scores predicted the amount of days exercised. Implicit and explicit processing appear to uniquely predict exercise behaviors and attitudes. Given that different implicit and explicit processes may drive certain exercise factors (e.g., intensity and frequency, respectively), these behaviors may contribute to different aspects of exercise dependence.

Using implicit attitudes of exercise importance to predict explicit exercise dependence symptoms and exercise behaviors

PubMed Central

Forrest, Lauren N.; Smith, April R.; Fussner, Lauren M.; Dodd, Dorian R.; Clerkin, Elise M.

2015-01-01

Objectives ”Fast” (i.e., implicit) processing is relatively automatic; “slow” (i.e., explicit) processing is relatively controlled and can override automatic processing. These different processing types often produce different responses that uniquely predict behaviors. In the present study, we tested if explicit, self-reported symptoms of exercise dependence and an implicit association of exercise as important predicted exercise behaviors and change in problematic exercise attitudes. Design We assessed implicit attitudes of exercise importance and self-reported symptoms of exercise dependence at Time 1. Participants reported daily exercise behaviors for approximately one month, and then completed a Time 2 assessment of self-reported exercise dependence symptoms. Method Undergraduate males and females (Time 1, N = 93; Time 2, N = 74) tracked daily exercise behaviors for one month and completed an Implicit Association Test assessing implicit exercise importance and subscales of the Exercise Dependence Questionnaire (EDQ) assessing exercise dependence symptoms. Results Implicit attitudes of exercise importance and Time 1 EDQ scores predicted Time 2 EDQ scores. Further, implicit exercise importance and Time 1 EDQ scores predicted daily exercise intensity while Time 1 EDQ scores predicted the amount of days exercised. Conclusion Implicit and explicit processing appear to uniquely predict exercise behaviors and attitudes. Given that different implicit and explicit processes may drive certain exercise factors (e.g., intensity and frequency, respectively), these behaviors may contribute to different aspects of exercise dependence. PMID:26195916

Acute coordinative exercise improves attentional performance in adolescents.

PubMed

Budde, Henning; Voelcker-Rehage, Claudia; Pietrabyk-Kendziorra, Sascha; Ribeiro, Pedro; Tidow, Günter

2008-08-22

Teachers complain about growing concentration deficits and reduced attention in adolescents. Exercise has been shown to positively affect cognitive performance. Due to the neuronal connection between the cerebellum and the frontal cortex, we hypothesized that cognitive performance might be influenced by bilateral coordinative exercise (CE) and that its effect on cognition might be already visible after short bouts of exercise. One hundred and fifteen healthy adolescents aged 13-16 years of an elite performance school were randomly assigned to an experimental and a control group and tested using the d2-test, a test of attention and concentration. Both groups performed the d2-test after a regular school lesson (pre-test), after 10 min of coordinative exercise and of a normal sport lesson (NSL, control group), respectively (post-test). Exercise was controlled for heart rate (HR). CE and NSL enhanced the d2-test performance from pre- to post-test significantly. ANOVA revealed a significant group (CE, NSL) by performance interaction in the d2-test indicating a higher improvement of CE as compared to NSL. HR was not significantly different between the groups. CE was more effective in completing the concentration and attention task. With the HR being the same in both groups we assume that the coordinative character of the exercise might be responsible for the significant differences. CE might lead to a pre-activation of parts of the brain which are also responsible for mediating functions like attention. Thus, our results support the request for more acute CE in schools, even in elite performance schools.

Long-term voluntary exercise prevents post-weaning social isolation-induced cognitive impairment in rats.

PubMed

Okudan, Nilsel; Belviranlı, Muaz

2017-09-30

This study aimed to determine the effect of exercise on locomotion, anxiety-related behavior, learning, and memory in socially isolated post-weaning rats, as well as the correlation between exercise and the concentration of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the hippocampus. Rats were randomly assigned to three groups: the control group; the social isolation group; the social isolation plus exercise (SIE) group. Social isolation conditions, with or without exercise were maintained for 90d, and then multiple behavioral tests, including the open-field test, elevated plus maze test, and Morris water maze (MWM) test were administered. Following behavioral assessment, hippocampal tissue samples were obtained for measurement of BDNF and NGF. There wasn't a significant difference in locomotor activity between the groups (P>0.05). Anxiety scores were higher in the socially isolated group (P<0.05) than in the SIE group (P<0.05). According to the probe trial session of the MWM test results, exercise training improved platform crossings' number in the socially isolated rats (P<0.05). Exercise training ameliorated social isolation-induced reduction in hippocampal BDNF and NGF content (P<0.05). These findings suggest that exercise training improves cognitive functions via increasing hippocampal BDNF and NGF concentrations in socially isolated post-weaning rats. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of combined aerobic and resistance exercise on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis.

PubMed

Lee, Yong Hee; Park, Soo Hyun; Yoon, Eun Sun; Lee, Chong-Do; Wee, Sang Ouk; Fernhall, Bo; Jae, Sae Young

2015-09-01

The effects of combined aerobic and resistance exercise training on central arterial stiffness and gait velocity in patients with chronic poststroke hemiparesis were investigated. Twenty-six patients with chronic poststroke hemiparesis were randomly assigned to either the combined aerobic and resistance exercise group (n = 14) or the control group (n = 12). The exercise intervention group received a combined aerobic and resistance exercise training (1 hr/day, three times/week for 16 wks), whereas the control group received usual care. Central arterial stiffness was determined by pulse wave velocity and augmentation index. Gait velocity was assessed using the 6-min walk test, 10-m walk test, and the Timed Up-and-Go test. Patients in the exercise intervention group had greater improvement of mean pulse wave velocity (P < 0.001), augmentation index (P = 0.048), and gait velocity (6-min walk test, P < 0.001; 10-m walk test, P < 0.001) than did patients in the control group. Patients in the exercise intervention group also had greater improvements in physical fitness component (grip strength, P < 0.001; muscular strength of upper and lower limbs, P < 0.027; flexibility, P < 0.001) when compared with control patients. The combined aerobic and resistance exercise program significantly reduced central arterial stiffness and increased gait velocity in patients with chronic poststroke hemiparesis.

Efficacy of a heat exchanger mask in cold exercise-induced asthma.

PubMed

Beuther, David A; Martin, Richard J

2006-05-01

To determine the efficacy of a novel mask device in limiting cold air exercise-induced decline in lung function in subjects with a history of exercise-induced asthma (EIA). In spite of appropriate medical therapy, many asthma patients are limited in cold weather activities. In study 1, 13 asthmatic subjects performed two randomized, single-blind treadmill exercise tests while breathing cold air (- 25 to - 15 degrees C) through a placebo or active heat exchanger mask. In study 2, five subjects with EIA performed three treadmill exercise tests while breathing cold air: one test using the heat exchanger mask, one test without the mask but with albuterol pretreatment, and one test with neither the mask nor albuterol pretreatment (unprotected exercise). For all studies, spirometry was performed before and at 5, 15, and 30 min after exercise challenge. For both studies, a total of 15 subjects with a history of asthma symptoms during cold air exercise were recruited. In study 1, the mean decrease (+/- SE) in FEV1 was 19 +/- 4.9% with placebo, and 4.3 +/- 1.6% with the active device (p = 0.0002). The mean decrease in maximum mid-expiratory flow (FEF(25-75)) was 31 +/- 5.7% with placebo and 4.7 +/- 1.7% with the active device (p = 0.0002). In study 2, the mean decrease in FEV1 was 6.3 +/- 3.9%, 11 +/- 3.7%, and 28 +/- 10% for the heat exchanger mask, albuterol pretreatment, and unprotected exercises, respectively (p = 0.4375 for mask vs albuterol, p = 0.0625 for mask vs unprotected exercise). The mean decrease in FEF(25-75) was 10 +/- 4.8%, 23 +/- 6.0%, and 36 +/- 11%, respectively (p = 0.0625 for mask vs albuterol, p = 0.0625 for mask vs unprotected exercise). This heat exchanger mask blocks cold exercise-induced decline in lung function at least as effectively as albuterol pretreatment.

Prevalence and prognostic value of exercise-induced ventricular arrhythmias.

PubMed

Partington, Sara; Myers, Jonathan; Cho, Shaun; Froelicher, Victor; Chun, Sung

2003-01-01

The purpose of this study was to determine the prevalence and prognostic significance of exercise-induced ventricular arrhythmias (EIVAs) in patients referred for exercise testing, considering the arrhythmic substrate and exercise-induced ischemia. EIVAs are frequently observed during exercise testing, but their prognostic significance is uncertain. The design of this study was a retrospective analysis of prospectively collected data, and it took place in 2 university-affiliated Veterans Affairs Medical Centers. Patients comprised 6213 consecutive males referred for exercise tests. We measured clinical exercise test responses and all-cause mortality after a mean follow-up of 6 +/- 4 years. EIVAs were defined as frequent premature ventricular contractions (PVCs) constituting >10% of all ventricular depolarizations during any 30 second electrocardiogram recording, or a run of > or =3 consecutive PVCs during exercise or recovery. A total of 1256 patients (20%) died during follow-up. EIVAs occurred in 503 patients (8%); the prevalence of EIVAs increased in older patients and in those with cardiopulmonary disease, resting PVCs, and ischemia during exercise. EIVAs were associated with mortality irrespective of the presence of cardiopulmonary disease or exercise-induced ischemia. In those without cardiopulmonary disease, mortality differed more so later in follow up than earlier. In those without resting PVCs, EIVAs were also predictive of mortality, but in those with resting PVCs, poorer prognosis was not worsened by the presence of EIVAs. Exercise induced ischemia does not affect the prognostic value of EIVAs, whereas the arrhythmic substrate does. EIVAs and resting PVCs are both independent predictors of mortality after consideration of other clinical and exercise-test variables. These findings are of limited clinical significance because of the modest change in risk and the lack of any established intervention. However, they explain some of the previous controversy and highlight the need to consider resting PVCs and follow-up duration in assessing the clinical implications of EIVAs.

Review of the development of concrete pavement surface types and their acoustic performance with time

NASA Astrophysics Data System (ADS)

Scofield, Larry A.

2005-09-01

Roadways have been constructed out of concrete pavements in the United States since the late 1800s. Numerous surface textures have been produced including burlap drag, astroturf, uniformly and random transverse tined, longitudinally tined, and both profile and whisper diamond grinding processes. Each surface evolved for specific reasons during the historical development of Portland Cement Concrete Pavements (PCCP).This paper reviews the development of these various surface texture types and the reasons for their evolution. In addition, results from both far field and near field acoustic testing are presented to evaluate the ``acoustic'' performance of these surfaces over time.For five surface types, 1/24 octave analysis were conducted on CPX data obtained with a single tire. The spectrum of each of these surface types is presented for comparison. For three of the surfaces, speed gradient testing, ranging between 25-75 MPH was conducted. 1/24 octave analysis of each of these runs was conducted so that that any speed induced spectrum shifts could be observed.The results to date indicate that the adverse tonal properties of some PCCP surfaces can be eliminated through diamond grinding and prevented by not constructing transverse tined PCCP.

Exercise limitation, exercise testing and exercise recommendations in sickle cell anemia.

PubMed

Connes, Philippe; Machado, Roberto; Hue, Olivier; Reid, Harvey

2011-01-01

Sickle cell anemia (SCA or SS homozygous sickle cell disease) is an inherited blood disorder caused by single nucleotide substitution in the β-globin gene that renders their hemoglobin (HbS) much less soluble than normal hemoglobin (HbA) when deoxygenated. The polymerization of HbS upon deoxygenation is the basic pathophysiologic event leading to RBC sickling, hemolysis, vasoocclusion and ultimately to chronic organ damage. The metabolic changes imposed by exercise may initiate sickling and vaso-occlusive episodes. Further, in patients with SCA, exercise limitation may be related to anemia or chronic complications such as pulmonary vascular disease, congestive heart failure and chronic parenchymal lung disease. Few studies have investigated the cardiorespiratory responses of patients with SCA during either symptom-limited maximal exercise test on cyclo-ergometer or during a six minute walk test. Therefore, patients are advised to start exercise slowly and progressively, to maintain adequate hydration during and after exercise, to avoid cold exposure or sudden change in temperature, and to avoid sports associated with mechanical trauma. There are, however, lack of evidence to allow practitioners to prescribe an exercise program for patients with SCA, and individuals are usually encouraged to exercise on a symptom-limited basis. Finally, this review will also highlight the basic principles that are often used for exercise practice and could be used for exercise prescription and rehabilitation in patients with sickle cell anemia.

Exaggerated blood pressure response to early stages of exercise stress testing and presence of hypertension.

PubMed

Schultz, Martin G; Picone, Dean S; Nikolic, Sonja B; Williams, Andrew D; Sharman, James E

2016-12-01

Exaggerated exercise blood pressure (EEBP) recorded during exercise testing at moderate-intensity is independently associated with cardiovascular mortality. It is hypothesized that EEBP may be indicative of underlying hypertension unnoticed by standard clinic (resting) BP measures (thus explaining increased mortality risk), but this has never been confirmed by association with hypertension defined using ambulatory BP monitoring, which was the aim of this study. Cross-sectional study. 100 consecutive patients free from coronary artery disease (aged 56±9 years, 72% male) underwent clinically indicated exercise stress testing. Exercise BP was recorded at each stage of the Bruce protocol. Presence of hypertension was defined as 24-hour systolic BP ≥130mmHg or daytime systolic BP ≥135mmHg. Exercise systolic BP at stage 1 and 2 of the test was significantly associated with the presence of hypertension (P<0.05), with the strongest association observed between stage 1 exercise systolic BP and 24-h systolic BP >130mmHg (AUC=0.752, 95% CI's 0.649-0.846, P<0.001). 79% of participants achieving systolic BP ≥150mmHg at stage 1 of the test were classified as having hypertension, with systolic BP >150mmHg predicting hypertension independently of age, sex and in-clinic hypertension status (OR=4.83, 95% CI's 1.62-14.39, P=0.005). Irrespective of resting BP, systolic BP ≥150mmHg during early stages of the Bruce exercise stress test is associated with presence of hypertension. EEBP should be a warning signal to health/exercise professionals on the presence of hypertension and the need to provide follow up care to reduce cardiovascular risk. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Benefits of HIV testing during military exercises.

PubMed

Gross, M L; Rendin, R W; Childress, C W; Kerstein, M D

1989-12-01

During U.S. Marine Corps Reserve summer 2-week active duty for training periods, 6,482 people were tested for human immunodeficiency virus (HIV). Testing at an initial exercise, Solar Flare, trained a cadre of contact teams to, in turn, train other personnel in phlebotomy and the HIV protocol at three other exercises (141 Navy Reserve and Inspector-Instructor hospital corpsmen were trained). Corpsmen could be trained with an indoctrination of 120 minutes and a mean of 15 phlebotomies. After 50 phlebotomies, the administration, identification, and labeling process plus phlebotomy could be completed in 90 seconds. HIV testing during military exercises is both good for training and cost-effective.

Clinical correlation between the 6-min walk test andcardiopulmonary exercise testing in patients with pulmonary arterial hypertension.

PubMed

Acar, Serap; Savcı, Sema; Kardibak, Didem; Özcan Kahraman, Buse; Akdeniz, Bahri; Özpelit, Ebru; Sevinç, Can

2016-12-20

The aims of the present study were to assess the relationship between the distance walked during the 6-min walk test (6MWT) and exercise capacity as determined by cardiopulmonary exercise testing (CPET) in patients with pulmonary arterial hypertension (PAH) and to investigate the prognostic value of the 6MWT in comparison to clinical parameters of CPET and echocardiography findings. Thirty PAH patients participated in the study. Subject characteristics and New York Heart Association (NYHA) classifications were recorded. All subjects completed the 6MWT and CPET. Relationships among the variables were analyzed by the Pearson correlation test. Correlation coefficients between 6MWT distance and other variables were determined by linear regression analysis. Distance walked in the 6MWT was significantly correlated with the following exercise parameters: peak oxygen consumption, work load, and metabolic equivalents. Additionally, cardiac index was correlated with peak oxygen consumption and metabolic equivalents. We also showed that cardiac index and age were two significant determinants for exercise performance, accounting for 35.4% of the variance in the 6MWT. The 6MWT provides information that may be a better index for the patient's NYHA functional class determination than maximal exercise testing.

Surgical treatment is effective in severe cases of exercise-induced laryngeal obstruction: A follow-up study.

PubMed

Norlander, Katarina; Johansson, Henrik; Jansson, Christer; Nordvall, Lennart; Nordang, Leif

2015-01-01

Surgery is an effective treatment in severe cases of supraglottic exercise-induced laryngeal obstruction (E-ILO). Conservatively treated subjects and subjects tested negative for E-ILO, who still experience breathing problems 1-3 years after diagnosis, tend to adjust their physical activity to a greater extent than surgically treated subjects. To investigate how symptoms and level of physical activity change over time in patients with E-ILO who have undergone surgery, patients with E-ILO treated conservatively and patients who tested negative for laryngeal obstruction at continuous laryngoscopy exercise-test (CLE-test). Patients referred for exercise-induced breathing difficulties answered questionnaires at diagnostic CLE-test and at follow-up. Questions regarded exercise-induced breathing problems, current physical activity level, and medical history of asthma and perennial allergy. Out of 84 invited subjects, 59 (70%) answered both questionnaires. Surgically treated subjects had less breathing problems at follow-up compared with conservatively treated subjects and subjects who tested negative (p < 0.001). None of the surgically treated subjects were less physically active or had changed sport due to exercise-induced dyspnoea, whereas 41.7% of the conservatively treated subjects had made such adjustments (p < 0.001).

Effects of exercise continued until anaerobic threshold on balance performance in male basketball players.

PubMed

Erkmen, Nurtekin; Suveren, Sibel; Göktepe, Ahmet Salim

2012-06-01

The objective of the present study was to determine the effects of exercise continued until the anaerobic threshold on balance performance in basketball players. Twelve male basketball players (age = 20.92 ± 2.81 years, body height = 192.72 ± 7.61 cm, body mass = 88.09 ± 8.41 kg, training experience = 7.17 ± 3.10 years) volunteered to participate in this study. A Kinesthetic Ability Trainer (KAT 2000 stabilometer) was used to measure the balance performance. Balance tests consisted of static tests on dominant, nondominant and double leg stance. The Bruce Protocol was performed by means of a treadmill. The exercise protocol was terminated when the subject passed the anaerobic threshold. After the exercise protocol, balance measurements were immediately repeated. Statistical differences between pre and post-exercise for dominant, nondominant and double leg stance were determined by the paired samples t-test according to the results of the test of normality. The post-exercise balance score on the dominant leg was significantly higher than pre-exercise (t = -2.758, p < 0.05). No differences existed between pre- and post-exercise in the balance scores of the nondominant leg after the exercise protocol (t = 0.428, p > 0.05). A significant difference was found between pre and post-exercise balance scores in the double leg stance (t = -2.354, p < 0.05). The main finding of this study was that an incremental exercise continued until the anaerobic threshold decreased balance performance on the dominant leg in basketball players, but did not alter it in the nondominant leg.

Study in Parkinson Disease of Exercise (SPARX): Translating high-intensity exercise from animals to humans

PubMed Central

Moore, Charity G.; Schenkman, Margaret; Kohrt, Wendy M.; Delitto, Anthony; Hall, Deborah A.; Corcos, Daniel

2013-01-01

A burgeoning literature suggests that exercise has a therapeutic benefit in persons with Parkinson disease (PD) and in animal models of PD, especially when animals exercise at high intensity. If exercise is to be prescribed as “first-line” or “add-on” therapy in patients with PD, we must demonstrate its efficacy and dose-response effects through testing phases similar to those used in the testing of pharmacologic agents. The SPARX Trial is a multicenter, randomized, controlled, single-blinded, Phase II study that we designed to test the feasibility of using high-intensity exercise to modify symptoms of PD and to simultaneously test the nonfutility of achieving a prespecified change in patients’ motor scores on the Unified Parkinson Disease Rating Scale (UPDRS). The trial began in May 2102 and is in the process of screening, enrolling, and randomly assigning 126 patients with early-stage PD to 1 of 3 groups: usual care (wait-listed controls), moderate-intensity exercise (4 days/week at 60%–65% maximal heart rate [HRmax]), or high-intensity exercise (4 days/week at 80%–85% HRmax). At 6-month follow-up, the trial is randomly reassigning usual care participants to a moderate-intensity or high-intensity exercise group for the remaining 6 months. The goals of the Phase II trial are to determine if participants can exercise at moderate and high intensities; to determine if either exercise yields benefits consistent with meaningful clinical change (nonfutility); and to document safety and attrition. The advantage of using a non-futility approach allows us to efficiently determine if moderate- or high-intensity exercise warrants further large-scale investigation in PD. PMID:23770108

Physical exercise increases involvement of motor networks as a compensatory mechanism during a cognitively challenging task.

PubMed

Ji, Lanxin; Pearlson, Godfrey D; Zhang, Xue; Steffens, David C; Ji, Xiaoqing; Guo, Hua; Wang, Lihong

2018-05-31

Neuroimaging studies suggest that older adults may compensate for declines in cognitive function through neural compensation and reorganization of neural resources. While neural compensation as a key component of cognitive reserve is an important factor that mediates cognitive decline, the field lacks a quantitative measure of neural compensatory ability, and little is known about factors that may modify compensation, such as physical exercise. Twenty-five healthy older adults participated in a 6-week dance training exercise program. Gait speed, cognitive function, and functional magnetic resonance imaging during a challenging memory task were measured before and after the exercise program. In this study, we used a newly proposed data-driven independent component analysis approach to measure neural compensatory ability and tested the effect of physical exercise on neural compensation through a longitudinal study. After the exercise program, participants showed significantly improved memory performance in Logical Memory Test (WMS(LM)) (P < .001) and Rey Auditory Verbal Learning Test (P = .001) and increased gait speed measured by the 6-minute walking test (P = .01). Among all identified neural networks, only the motor cortices and cerebellum showed greater involvement during the memory task after exercise. Importantly, subjects who activated the motor network only after exercise (but not before exercise) showed WMS(LM) increases. We conclude that physical exercise improved gait speed, cognitive function, and compensatory ability through increased involvement of motor-related networks. Copyright © 2018 John Wiley & Sons, Ltd.

Patterning of physiological and affective responses in older active adults during a maximal graded exercise test and self-selected exercise.

PubMed

Smith, Ashleigh E; Eston, Roger; Tempest, Gavin D; Norton, Belinda; Parfitt, Gaynor

2015-09-01

The American College of Sports Medicine has highlighted the importance of considering the physiological and affective responses to exercise when setting exercise intensity. Here, we examined the relationship between exercise intensity and physiological and affective responses in active older adults. Eighteen participants (60-74 years; 64.4 ± 3.9; 8 women) completed a maximal graded exercise test (GXT) on a treadmill. Since time to exhaustion in the GXT differed between participants, heart rate (HR), oxygen consumption (VO2), affective valence (affect) and rating of perceived exertion (RPE) were expressed relative to the individually determined ventilatory threshold (%atVT). During the GXT, VO2, HR and RPE increased linearly (all P < 0.01). Affect declined initially (but remained positive) (P = 0.03), stabilised around VT (still positive) (P > 0.05) and became negative towards the end of the test (P < 0.01). In a subsequent session, participants completed a 20-min bout of self-selected exercise (at a preferred intensity). Initially, participants chose to exercise below VT (88.2 ± 17.4 %VO2atVT); however, the intensity was adjusted to work at, or above VT (107.7 ± 19.9 %VO2atVT) after 10 min (P < 0.001), whilst affect remained positive. Together, these findings indicate that exercise around VT, whether administered during an exercise test, or self-selected by the participant, is likely to result in positive affective responses in older adults.

Exercise in Patients on Dialysis: A Multicenter, Randomized Clinical Trial

PubMed Central

Manfredini, Fabio; Mallamaci, Francesca; D’Arrigo, Graziella; Baggetta, Rossella; Bolignano, Davide; Torino, Claudia; Lamberti, Nicola; Bertoli, Silvio; Ciurlino, Daniele; Rocca-Rey, Lisa; Barillà, Antonio; Battaglia, Yuri; Rapanà, Renato Mario; Zuccalà, Alessandro; Bonanno, Graziella; Fatuzzo, Pasquale; Rapisarda, Francesco; Rastelli, Stefania; Fabrizi, Fabrizio; Messa, Piergiorgio; De Paola, Luciano; Lombardi, Luigi; Cupisti, Adamasco; Fuiano, Giorgio; Lucisano, Gaetano; Summaria, Chiara; Felisatti, Michele; Pozzato, Enrico; Malagoni, Anna Maria; Castellino, Pietro; Aucella, Filippo; Abd ElHafeez, Samar; Provenzano, Pasquale Fabio; Tripepi, Giovanni; Catizone, Luigi

2017-01-01

Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n=145) or walking exercise (n=151); 227 patients (exercise n=104; control n=123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P<0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P=0.001 between groups). The cognitive function score (P=0.04) and quality of social interaction score (P=0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis. PMID:27909047

A prognostic scoring system for arm exercise stress testing.

PubMed

Xie, Yan; Xian, Hong; Chandiramani, Pooja; Bainter, Emily; Wan, Leping; Martin, Wade H

2016-01-01

Arm exercise stress testing may be an equivalent or better predictor of mortality outcome than pharmacological stress imaging for the ≥50% for patients unable to perform leg exercise. Thus, our objective was to develop an arm exercise ECG stress test scoring system, analogous to the Duke Treadmill Score, for predicting outcome in these individuals. In this retrospective observational cohort study, arm exercise ECG stress tests were performed in 443 consecutive veterans aged 64.1 (11.1) years. (mean (SD)) between 1997 and 2002. From multivariate Cox models, arm exercise scores were developed for prediction of 5-year and 12-year all-cause and cardiovascular mortality and 5-year cardiovascular mortality or myocardial infarction (MI). Arm exercise capacity in resting metabolic equivalents (METs), 1 min heart rate recovery (HRR) and ST segment depression ≥1 mm were the stress test variables independently associated with all-cause and cardiovascular mortality by step-wise Cox analysis (all p<0.01). A score based on the relation HRR (bpm)+7.3×METs-10.5×ST depression (0=no; 1=yes) prognosticated 5-year cardiovascular mortality with a C-statistic of 0.81 before and 0.88 after adjustment for significant demographic and clinical covariates. Arm exercise scores for the other outcome end points yielded C-statistic values of 0.77-0.79 before and 0.82-0.86 after adjustment for significant covariates versus 0.64-0.72 for best fit pharmacological myocardial perfusion imaging models in a cohort of 1730 veterans who were evaluated over the same time period. Arm exercise scores, analogous to the Duke Treadmill Score, have good power for prediction of mortality or MI in patients who cannot perform leg exercise.

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons

PubMed Central

Noble, Emily E.; Mavanji, Vijayakumar; Little, Morgan R.; Billington, Charles J.; Kotz, Catherine M.; Wang, ChuanFeng

2014-01-01

Background Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. Methods To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for seven weeks of exercise intervention. Results Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. Conclusions These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. PMID:24755094

Exercise reduces diet-induced cognitive decline and increases hippocampal brain-derived neurotrophic factor in CA3 neurons.

PubMed

Noble, Emily E; Mavanji, Vijayakumar; Little, Morgan R; Billington, Charles J; Kotz, Catherine M; Wang, ChuanFeng

2014-10-01

Previous studies have shown that a western diet impairs, whereas physical exercise enhances hippocampus-dependent learning and memory. Both diet and exercise influence expression of hippocampal brain-derived neurotrophic factor (BDNF), which is associated with improved cognition. We hypothesized that exercise reverses diet-induced cognitive decline while increasing hippocampal BDNF. To test the effects of exercise on hippocampal-dependent memory, we compared cognitive scores of Sprague-Dawley rats exercised by voluntary running wheel (RW) access or forced treadmill (TM) to sedentary (Sed) animals. Memory was tested by two-way active avoidance test (TWAA), in which animals are exposed to a brief shock in a specific chamber area. When an animal avoids, escapes or has reduced latency to do either, this is considered a measure of memory. In a second experiment, rats were fed either a high-fat diet or control diet for 16 weeks, then randomly assigned to running wheel access or sedentary condition, and TWAA memory was tested once a week for 7 weeks of exercise intervention. Both groups of exercised animals had improved memory as indicated by reduced latency to avoid and escape shock, and increased avoid and escape episodes (p<0.05). Exposure to a high-fat diet resulted in poor performance during both the acquisition and retrieval phases of the memory test as compared to controls. Exercise reversed high-fat diet-induced memory impairment, and increased brain-derived neurotrophic factor (BDNF) in neurons of the hippocampal CA3 region. These data suggest that exercise improves memory retrieval, particularly with respect to avoiding aversive stimuli, and may be beneficial in protecting against diet induced cognitive decline, likely via elevated BDNF in neurons of the CA3 region. Published by Elsevier Inc.

Overcoming barriers to exercise among parents: a social cognitive theory perspective.

PubMed

Mailey, Emily L; Phillips, Siobhan M; Dlugonski, Deirdre; Conroy, David E

2016-08-01

Parents face numerous barriers to exercise and exhibit high levels of inactivity. Examining theory-based determinants of exercise among parents may inform interventions for this population. The purpose of this study was to test a social-cognitive model of parental exercise participation over a 12-month period. Mothers (n = 226) and fathers (n = 70) of children <16 completed measures of exercise, barriers self-efficacy, perceived barriers, and exercise planning at baseline and 1 year later. Panel analyses were used to test the hypothesized relationships. Barriers self-efficacy was related to exercise directly and indirectly through perceived barriers and prioritization/planning. Prioritization and planning also mediated the relationship between perceived barriers and exercise. These paths remained significant at 12 months. These results suggest efforts to increase exercise in parents should focus on improving confidence to overcome exercise barriers, reducing perceptions of barriers, and helping parents make specific plans for prioritizing and engaging in exercise.

Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness

PubMed Central

Zhang, Rubin; Zhan, Likui; Sun, Shaoming; Peng, Wei; Sun, Yining

2017-01-01

The maximum oxygen uptake (V̇O2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to determine V̇O2 max in young healthy male adults. Thirty-two young healthy male adults (32 males; age range: 20-35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (CE) to directly obtain measured V̇O2 max. Subjects then completed the progressive multistage test on the RSE beginning at 50W and including additional stages of 70, 90, 110, 130, and 150W, and the RSE YMCA submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. A metabolic equation was derived from the RSE multistage exercise test to predict oxygen consumption (V̇O2) from power output (W) during the submaximal exercise test (V̇O2 (mL·min-1 )=12.4 ×W(watts)+3.5 mL·kg-1·min-1×M+160mL·min-1, R2= 0.91, standard error of the estimate (SEE) = 134.8mL·min-1). A high correlation was observed between the RSE YMCA estimated V̇O2 max and the CE measured V̇O2 max (r=0.87). The mean difference between estimated and measured V̇O2 max was 2.5 mL·kg-1·min-1, with an SEE of 3.55 mL·kg-1·min-1. The data suggest that the RSE YMCA submaximal exercise test is valid for predicting V̇O2 max in young healthy male adults. The findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting V̇O2 max. The newly-designed RSE may be potentially further developed as an alternative ergometer for assessing cardiorespiratory fitness and the promotion of personalized health interventions for health care professionals. Key points The rectilinear stepping exercise is a simple modality of exercise, which requires only up and down movements of the legs. It overcomes the mechanical dead centers of circular motion and is mechanically efficient. It is potentially applicable to a large group of populations. The RSE gives an accurate measurement of power output and ensures a constant power output independent of stepping cadence. The RSE submaximal exercise test is valid and feasible for estimating V̇O2 max in young healthy male adults compared with the CE maximal exercise test. The rectilinear stepping exercise is an effective submaximal exercise mode for predicting V̇O2 max. The RSE designed for this study may be potentially developed as a new and alternative ergometer to assess cardiorespiratory fitness and could be used in the future by healthcare professionals to promote personalized health interventions. PMID:28912653

Estimating the total energy demand for supra-maximal exercise using the VO2-power regression from an incremental exercise test.

PubMed

Aisbett, B; Le Rossignol, P

2003-09-01

The VO2-power regression and estimated total energy demand for a 6-minute supra-maximal exercise test was predicted from a continuous incremental exercise test. Sub-maximal VO2-power co-ordinates were established from the last 40 seconds (s) of 150-second exercise stages. The precision of the estimated total energy demand was determined using the 95% confidence interval (95% CI) of the estimated total energy demand. The linearity of the individual VO2-power regression equations was determined using Pearson's correlation coefficient. The mean 95% CI of the estimated total energy demand was 5.9 +/- 2.5 mL O2 Eq x kg(-1) x min(-1), and the mean correlation coefficient was 0.9942 +/- 0.0042. The current study contends that the sub-maximal VO2-power co-ordinates from a continuous incremental exercise test can be used to estimate supra-maximal energy demand without compromising the precision of the accumulated oxygen deficit (AOD) method.

Exercise Blood Pressure Guidelines: Time to Re-evaluate What is Normal and Exaggerated?

PubMed

Currie, Katharine D; Floras, John S; La Gerche, Andre; Goodman, Jack M

2018-03-24

Blood pressure responses to graded exercise testing can provide important diagnostic and prognostic information. While published guidelines outline what constitutes a "normal" and "abnormal" (i.e., exaggerated) blood pressure response to exercise testing, the widespread use of exaggerated blood pressure responses as a clinical tool is limited due to sparse and inconsistent data. A review of the original sources from these guidelines reveals an overall lack of empirical evidence to support both the normal blood pressure responses and their upper limits. In this current opinion, we critically evaluate the current exercise blood pressure guidelines including (1) the normal blood pressure responses to graded exercise testing; (2) the upper limits of this normal response; (3) the blood pressure criteria for test termination; and (4) the thresholds for exaggerated blood pressure responses. We provide evidence that exercise blood pressure responses vary according to subject characteristics, and subsequently a re-evaluation of what constitutes normal and abnormal responses is necessary to strengthen the clinical utility of this assessment.

Differential effects of water-based exercise on the cognitive function in independent elderly adults.

PubMed

Sato, Daisuke; Seko, Chihiro; Hashitomi, Tatsuya; Sengoku, Yasuo; Nomura, Takeo

2015-04-01

Physical exercise has been reported to be the most effective method to improve cognitive function and brain health, but there is as yet no research on the effect of water-based exercise. The aim of the present study was to compare the effects of water-based exercise with and without cognitive stimuli on cognitive and physical functions. The design is a single-blind randomized controlled study. Twenty-one participants were randomly assigned to a normal water-based exercise (Nor-WE) group or a cognitive water-based exercise (Cog-WE) group. The exercise sessions were divided into two exercise series: a 10-min series of land-based warm-up, consisting of flexibility exercises, and a 50-min series of exercises in water. The Nor-WE consisted of 10 min of walking, 30 min of strength and stepping exercise, including stride over, and 10 min of stretching and relaxation in water. The Cog-WE consisted of 10 min of walking, 30 min of water-cognitive exercises, and 10 min of stretching and relaxation in water. Cognitive function, physical function, and ADL were measured before the exercise intervention (pre-intervention) and 10 weeks after the intervention (post-intervention). Participation in the Cog-WE performed significantly better on the pegboard test and the choice stepping reaction test and showed a significantly improved attention, memory, and learning, and in the general cognitive function (measured as the total score in the 5-Cog test). Participation in the Nor-WE dramatically improved walking ability and lower limb muscle strength. Our results reveal that the benefits elderly adults may obtain from water-based exercise depend on the characteristics of each specific exercise program. These findings highlight the importance of prescription for personalized water-based exercises to elderly adults to improve cognitive function.

Endurance exercise intensity determination in the rehabilitation of coronary artery disease patients: a critical re-appraisal of current evidence.

PubMed

Hansen, Dominique; Stevens, An; Eijnde, Bert O; Dendale, Paul

2012-01-01

In the care of coronary artery disease (CAD) patients, the benefits of exercise therapy are generally established. Even though the selected endurance exercise intensity might affect medical safety, therapy adherence and effectiveness in the rehabilitation of CAD patients in how to determine endurance exercise intensity properly remains difficult. The aim of this review is to describe the available methods for endurance exercise intensity determination in the rehabilitation of CAD patients, accompanied with their (dis)advantages, validity and reproducibility. In general, endurance exercise intensity can objectively be determined in CAD patients by calculating a fraction of maximal exercise tolerance and/or determining ventilatory threshold after execution of a cardiopulmonary exercise test with ergospirometry. This can be translated to a corresponding training heart rate (HR) or workload. In the absence of ergospirometry equipment, target exercise HR can be calculated directly by different ways (fraction of maximal HR and/or Karvonen formula), and/or anaerobic threshold can be determined. However, the use of HR for determining exercise intensity during training sessions seems complicated, because many factors/conditions affect the HR. In this regard, proper standardization of the exercise sessions, as well as exercise testing, might be required to improve the accuracy of exercise intensity determination. Alternatively, subjective methods for the determination of endurance exercise intensity in CAD patients, such as the Borg ratings of perceived exertion and the talk test, have been developed. However, these methods lack proper validity and reliability to determine endurance exercise intensity in CAD patients. In conclusion, a practical and systematic approach for the determination of endurance exercise intensity in CAD patients is presented in this article.

Narrative and framing: a test of an integrated message strategy in the exercise context.

PubMed

Gray, Jennifer B; Harrington, Nancy G

2011-03-01

Health communication interventions encouraging exercise may aid in mitigating the obesity crisis in the United States. Although much research has investigated behavioral predictors of exercise, little work has explored message characteristics most persuasive in the exercise context. The purpose of this study, therefore, was to test a message strategy drawing on previous work in health behavior theory combined with persuasion theories (exemplification theory and prospect theory) to encourage positive exercise attitudes, control beliefs, and intentions. The authors report the results of a controlled experiment testing messages using gain or loss frames and narrative or statistical evidence. Results indicate that gain-framed messages are significantly more successful in promoting positive exercise variables and are perceived as more effective than are loss-framed or control messages. The authors discuss the implications of the results for future research.

Evaluation of anaerobic threshold in non-pregnant and pregnant rats.

PubMed

Netto, Aline Oliveira; Macedo, Nathália C D; Gallego, Franciane Q; Sinzato, Yuri K; Volpato, Gustavo T; Damasceno, Débora C

2017-01-01

Several studies present different methodologies and results about intensity exercise, and many of them are performed in male rats. However, the impact of different type, intensity, frequency and duration of exercise on female rats needs more investigation. From the analysis of blood lactate concentration during lactate minimum test (LacMin) in the swimming exercise, the anaerobic threshold (AT) was identified, which parameter is defined as the transition point between aerobic and anaerobic metabolism. LacMin test is considered a good indicator of aerobic conditioning and has been used in prescription of training in different exercise modalities. However, there is no evidence of LacMin test in female rats. The objective was to determine AT in non-pregnant and pregnant Wistar rats. The LacMin test was performed and AT defined for mild exercise intensity was from a load equivalent to 1% of body weight (bw), moderate exercise as carrying 4% bw and severe intensity as carrying 7% bw. In pregnant rats, the AT was reached at a lower loading from 5.0% to 5.5% bw, while in non-pregnant the load was from 5.5% to 6.0% bw. Thus, this study was effective to identify exercise intensities in pregnant and non-pregnant rats using anaerobic threshold by LacMin test.

Physiological and perceptual responses to incremental exercise testing in healthy men: effect of exercise test modality.

PubMed

Muscat, Kristina M; Kotrach, Houssam G; Wilkinson-Maitland, Courtney A; Schaeffer, Michele R; Mendonca, Cassandra T; Jensen, Dennis

2015-11-01

In a randomized cross-over study of 15 healthy men aged 20-30 years, we compared physiological and perceptual responses during treadmill and cycle exercise test protocols matched for increments in work rate - the source of increased locomotor muscle metabolic and contractile demands. The rates of O2 consumption and CO2 production were higher at the peak of treadmill versus cycle testing (p ≤ 0.05). Nevertheless, work rate, minute ventilation, tidal volume (VT), breathing frequency (fR), inspiratory capacity (IC), inspiratory reserve volume (IRV), tidal esophageal (Pes,tidal) and transdiaphragmatic pressure swings (Pdi,tidal), peak expiratory gastric pressures (Pga,peak), the root mean square of the diaphragm electromyogram (EMGdi,rms) expressed as a percentage of maximum EMGdi,rms (EMGdi,rms%max), and dyspnea ratings were similar at the peak of treadmill versus cycle testing (p > 0.05). Ratings of leg discomfort were higher at the peak of cycle versus treadmill exercise (p ≤ 0.05), even though peak O2 consumption was lower during cycling. Oxygen consumption, CO2 production, minute ventilation, fR, Pes,tidal, Pdi,tidal and Pga,peak were higher (p ≤ 0.05), while VT, IC, IRV, EMGdi,rms%max, and ratings of dyspnea and leg discomfort were similar (p > 0.05) at all or most submaximal work rates during treadmill versus cycle exercise. Our findings highlight important differences (and similarities) in physiological and perceptual responses at maximal and submaximal work rates during incremental treadmill and cycle exercise testing protocols. The lack of effect of exercise test modality on peak work rate advocates for the use of this readily available parameter to optimize training intensity determination, regardless of exercise training mode.

Calculation of Resistive Loads for Elastic Resistive Exercises.

PubMed

Picha, Kelsey; Uhl, Tim

2018-03-14

What is the correct resistive load to start resistive training with elastic resistance to gain strength? This question is typically answered by the clinician's best estimate and patient's level of discomfort without objective evidence. To determine the average level of resistance to initiate a strengthening routine with elastic resistance following isometric strength testing. Cohort. Clinical. 34 subjects (31 ± 13 y, 73 ± 17 kg, 170 ± 12 cm). The force produced was measured in Newtons (N) with an isometric dynamometer. The force distance was the distance from center of joint to location of force applied was measured in meters to calculate torque that was called "Test Torque" for the purposes of this report. This torque data was converted to "Exercise Load" in pounds based on the location where the resistance was applied, specifically the distance away from the center of rotation of the exercising limb. The average amount of exercise load as percentage of initial Test Torque for each individual for each exercise was recorded to determine what the average level of resistance that could be used for elastic resistance strengthening program. The percentage of initial test torque calculated for the exercise was recorded for each exercise and torque produced was normalized to body weight. The average percentage of maximal isometric force that was used to initiate exercises was 30 ± 7% of test torque. This provides clinicians with an objective target load to start elastic resistance training. Individual variations will occur but utilization of a load cell during elastic resistance provides objective documentation of exercise progression.

Effects of exercise and Kinesio taping on abdominal recovery in women with cesarean section: a pilot randomized controlled trial.

PubMed

Gürşen, Ceren; İnanoğlu, Deniz; Kaya, Serap; Akbayrak, Türkan; Baltacı, Gül

2016-03-01

Abdominal muscle strength decreases and fat ratio in the waist region increases following cesarean section. Kinesio taping (KT) is an easily applicable method and stimulates muscle activation. The aim of this pilot randomized controlled trial (RCT) was to investigate the effects of KT combined with exercise in women with cesarean section on abdominal recovery compared to the exercise alone. Twenty-four women in between the fourth and sixth postnatal months who had cesarean section were randomly assigned to KT + exercise (n = 12) group or exercise group (n = 12). KT was applied twice a week for 4 weeks on rectus abdominis, oblique abdominal muscles and cesarean incision. All women were instructed to carry out posterior pelvic tilt, core stabilization and abdominal correction exercises. Outcome measures were evaluated with the manual muscle test, sit-up test, abdominal endurance test, Visual Analog Scale (VAS), circumference measurements and Roland Morris Disability Questionnaire (RMDQ). Mann-Whitney U and Wilcoxon tests were used to analyze data. p < 0.05 was considered as statistically significant. The improvement observed in the KT + exercise group was significantly greater compared to the exercise group in terms of the strength of the rectus abdominis muscle, sit-up test, VAS, measurements of the waist circumference and RMDQ (p < 0.05). It appears that the addition of KT to abdominal exercises in the postnatal physiotherapy program provides greater benefit for the abdominal recovery in women with cesarean section. Further studies with larger sample sizes and long-term follow-up are needed to verify these results.

Test-Retest Reliability of Rating of Perceived Exertion and Agreement With 1-Repetition Maximum in Adults.

PubMed

Bove, Allyn M; Lynch, Andrew D; DePaul, Samantha M; Terhorst, Lauren; Irrgang, James J; Fitzgerald, G Kelley

2016-09-01

Study Design Clinical measurement. Background It has been suggested that rating of perceived exertion (RPE) may be a useful alternative to 1-repetition maximum (1RM) to determine proper resistance exercise dosage. However, the test-retest reliability of RPE for resistance exercise has not been determined. Additionally, prior research regarding the relationship between 1RM and RPE is conflicting. Objectives The purpose of this study was to (1) determine test-retest reliability of RPE related to resistance exercise and (2) assess agreement between percentages of 1RM and RPE during quadriceps resistance exercise. Methods A sample of participants with and without knee pathology completed a series of knee extension exercises and rated the perceived difficulty of each exercise on a 0-to-10 RPE scale, then repeated the procedure 1 to 2 weeks later for test-retest reliability. To determine agreement between RPE and 1RM, participants completed knee extension exercises at various percentages of their 1RM (10% to 130% of predicted 1RM) and rated the perceived difficulty of each exercise on a 0-to-10 RPE scale. Percent agreement was calculated between the 1RM and RPE at each resistance interval. Results The intraclass correlation coefficient indicated excellent test-retest reliability of RPE for quadriceps resistance exercises (intraclass correlation coefficient = 0.895; 95% confidence interval: 0.866, 0.918). Overall percent agreement between RPE and 1RM was 60%, but agreement was poor within the ranges that would typically be used for training (50% 1RM for muscle endurance, 70% 1RM and greater for strength). Conclusion Test-retest reliability of perceived exertion during quadriceps resistance exercise was excellent. However, agreement between the RPE and 1RM was poor, especially in common training zones for knee extensor strengthening. J Orthop Sports Phys Ther 2016;46(9):768-774. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6498.

Impact of Stimulant Medication Use on Heart Rate and Systolic Blood Pressure During Submaximal Exercise Treadmill Testing in Adolescents.

PubMed

Westover, Arthur N; Nakonezny, Paul A; Adinoff, Bryon; Brown, Edson Sherwood; Halm, Ethan A

2016-12-01

Inappropriately decreased heart rate (HR) during peak exercise and delayed heart rate recovery (HRR) has been observed in adult users of stimulant medications who underwent exercise testing, suggesting autonomic adaptation to chronic stimulant exposure. In the general population, this pattern of hemodynamic changes is associated with increased mortality risk. Whether the same pattern of hemodynamic changes might be observed in adolescent stimulant medication users undergoing exercise testing is unknown. Among adolescents (aged 12 to 20 years) that underwent submaximal exercise treadmill testing from 1999 to 2004 in the National Health and Nutrition Examination Survey, propensity score matching of stimulant medication users (n = 89) to matched nonusers (n = 267) was conducted. Testing consisted of a 3-minute warm-up period, two 3-minute exercise stages, and three 1-minute recovery periods, with the goal of reaching 75% of the predicted HR maximum. A linear mixed model analysis was used to evaluate the effect of stimulant exposure on each of the exercise outcomes. Stimulant medication users compared to matched nonusers had a lower peak HR in Stage 2 (154.9 vs. 158.3 beats/minute [bpm], p = 0.055) and lower HR at 1-minute recovery (142.2 vs. 146.4 bpm, p = 0.030). However, submaximal HRR at 1 minute did not differ between stimulant users and matched nonusers (13.0 vs. 12.1 bpm, p = 0.38). Duration of stimulant use was not related to these outcomes. Adolescent stimulant medication users compared to matched nonusers demonstrated a trend toward decreased HR during submaximal exercise, which is potential evidence of chronic adaptation with stimulant exposure. There was no evidence for delayed HRR in this study, and thus, no evidence for decreased parasympathetic activity during initial exercise recovery. Exercise testing outcomes may have utility in future research as a method to assess stimulant-associated autonomic nervous system adaptations.

Fibroblast growth factor 21 is required for beneficial effects of exercise during chronic high-fat feeding.

PubMed

Loyd, Christine; Magrisso, I Jack; Haas, Michael; Balusu, Sowmya; Krishna, Radha; Itoh, Nobuyuki; Sandoval, Darleen A; Perez-Tilve, Diego; Obici, Silvana; Habegger, Kirk M

2016-09-01

Exercise is an effective therapy against the metabolic syndrome. However, the molecular pathways underlying the advantageous effects of exercise are elusive. Glucagon receptor signaling is essential for exercise benefits, and recent evidence indicates that a downstream effector of glucagon, fibroblast growth factor 21 (FGF21), is implicated in this response. Therefore, we tested the hypothesis that FGF21 action is necessary in mediating metabolic effects of exercise. We utilized acute exhaustive treadmill exercise in Wistar rats to identify a putative, concomitant increase in plasma glucagon and FGF21 with the increase in glucose and lactate following exercise. To test the necessity of FGF21 action in the exercise response, we exposed FGF21 congenitally deficient mice (Fgf21(-/-)) and their wild-type (Wt) littermates to chronic high-fat (HF) feeding and inoperable (sedentary) or operable (exercise) voluntary running wheels. Physiological tests were performed to assess the role of FGF21 in the beneficial effect of exercise on glucose metabolism. Wt and Fgf21(-/-) littermates exhibited similar running behavior, and exercise was effective in suppressing weight and fat mass gain and dyslipidemia independently of genotype. However, exercise failed to positively affect hepatic triglyceride content and glucose tolerance in HF diet-fed Fgf21(-/-) mice. Furthermore, Fgf21(-/-) mice exhibited an impaired adaptation to exercise training, including reduced AMP-activated protein kinase activity in skeletal muscle. This study demonstrates that FGF21 action is necessary to achieve the full metabolic benefits of exercise during chronic HF feeding. Copyright © 2016 the American Physiological Society.

Fibroblast growth factor 21 is required for beneficial effects of exercise during chronic high-fat feeding

PubMed Central

Loyd, Christine; Magrisso, I. Jack; Haas, Michael; Balusu, Sowmya; Krishna, Radha; Itoh, Nobuyuki; Sandoval, Darleen A.; Perez-Tilve, Diego; Obici, Silvana

2016-01-01

Exercise is an effective therapy against the metabolic syndrome. However, the molecular pathways underlying the advantageous effects of exercise are elusive. Glucagon receptor signaling is essential for exercise benefits, and recent evidence indicates that a downstream effector of glucagon, fibroblast growth factor 21 (FGF21), is implicated in this response. Therefore, we tested the hypothesis that FGF21 action is necessary in mediating metabolic effects of exercise. We utilized acute exhaustive treadmill exercise in Wistar rats to identify a putative, concomitant increase in plasma glucagon and FGF21 with the increase in glucose and lactate following exercise. To test the necessity of FGF21 action in the exercise response, we exposed FGF21 congenitally deficient mice (Fgf21−/−) and their wild-type (Wt) littermates to chronic high-fat (HF) feeding and inoperable (sedentary) or operable (exercise) voluntary running wheels. Physiological tests were performed to assess the role of FGF21 in the beneficial effect of exercise on glucose metabolism. Wt and Fgf21−/− littermates exhibited similar running behavior, and exercise was effective in suppressing weight and fat mass gain and dyslipidemia independently of genotype. However, exercise failed to positively affect hepatic triglyceride content and glucose tolerance in HF diet-fed Fgf21−/− mice. Furthermore, Fgf21−/− mice exhibited an impaired adaptation to exercise training, including reduced AMP-activated protein kinase activity in skeletal muscle. This study demonstrates that FGF21 action is necessary to achieve the full metabolic benefits of exercise during chronic HF feeding. PMID:27445299

Carryover effect of hip and knee exercises program on functional performance in individuals with patellofemoral pain syndrome

PubMed Central

Ahmed Hamada, Hamada; Hussein Draz, Amira; Koura, Ghada Mohamed; Saab, Ibtissam M.

2017-01-01

[Purpose] This study was carried out to investigate the carryover effect of hip and knee exercises program on functional performance (single legged hop test as functional performance test and Kujala score for functional activities). [Subjects and Methods] Thirty patients with patellofemoral pain syndrome were randomly assigned into two equal groups. Group (A) consisted of 15 patients undergoing hip strengthening exercises for four weeks then measuring all variables followed by additional four weeks of knee exercises program then measuring all variables again. Group (B): consisted of 15 patients undergoing knee exercises program for four weeks then measuring all variables followed by additional four weeks of hip strengthening exercises then measuring all variables. Functional abilities and knee muscles performance were assessed using Kujala questionnaire and single legged hop test respectively pre and after the completion of the first 4 weeks then after 8 weeks for both groups. [Results] Significantly increase in Kujala questionnaire in group A compared with group B was observed. While, there were significant increase in single legged hop performance test in group B compared with group A. [Conclusion] Starting with hip exercises improve the performance of subjects more than functional activities while starting with knee exercises improve the functional activities of subjects more than performance. PMID:28878459

Carryover effect of hip and knee exercises program on functional performance in individuals with patellofemoral pain syndrome.

PubMed

Ahmed Hamada, Hamada; Hussein Draz, Amira; Koura, Ghada Mohamed; Saab, Ibtissam M

2017-08-01

[Purpose] This study was carried out to investigate the carryover effect of hip and knee exercises program on functional performance (single legged hop test as functional performance test and Kujala score for functional activities). [Subjects and Methods] Thirty patients with patellofemoral pain syndrome were randomly assigned into two equal groups. Group (A) consisted of 15 patients undergoing hip strengthening exercises for four weeks then measuring all variables followed by additional four weeks of knee exercises program then measuring all variables again. Group (B): consisted of 15 patients undergoing knee exercises program for four weeks then measuring all variables followed by additional four weeks of hip strengthening exercises then measuring all variables. Functional abilities and knee muscles performance were assessed using Kujala questionnaire and single legged hop test respectively pre and after the completion of the first 4 weeks then after 8 weeks for both groups. [Results] Significantly increase in Kujala questionnaire in group A compared with group B was observed. While, there were significant increase in single legged hop performance test in group B compared with group A. [Conclusion] Starting with hip exercises improve the performance of subjects more than functional activities while starting with knee exercises improve the functional activities of subjects more than performance.

Cardiorespiratory endurance evaluation using heart rate analysis during ski simulator exercise and the Harvard step test in elementary school students.

PubMed

Lee, Hyo Taek; Roh, Hyo Lyun; Kim, Yoon Sang

2016-01-01

[Purpose] Efficient management using exercise programs with various benefits should be provided by educational institutions for children in their growth phase. We analyzed the heart rates of children during ski simulator exercise and the Harvard step test to evaluate the cardiopulmonary endurance by calculating their post-exercise recovery rate. [Subjects and Methods] The subjects (n = 77) were categorized into a normal weight and an overweight/obesity group by body mass index. They performed each exercise for 3 minutes. The cardiorespiratory endurance was calculated using the Physical Efficiency Index formula. [Results] The ski simulator and Harvard step test showed that there was a significant difference in the heart rates of the 2 body mass index-based groups at each minute. The normal weight and the ski-simulator group had higher Physical Efficiency Index levels. [Conclusion] This study showed that a simulator exercise can produce a cumulative load even when performed at low intensity, and can be effectively utilized as exercise equipment since it resulted in higher Physical Efficiency Index levels than the Harvard step test. If schools can increase sport durability by stimulating students' interests, the ski simulator exercise can be used in programs designed to improve and strengthen students' physical fitness.

Effect of Physical Exercise on Platelet Reactivity in Patients with Dual Antiplatelet Therapy.

PubMed

Brunner, Stefan; Rizas, Konstantinos; Hamm, Wolfgang; Mehr, Michael; Lackermair, Korbinian

2018-06-14

It is known that physical exercise may increase platelet activity. However, the effect of exercise on platelet reactivity in patients on dual antiplatelet therapy has not been investigated yet. In our study, 21 patients with coronary artery disease on dual antiplatelet therapy and 10 controls were enrolled. We performed an exercise test using a cycle ergometer and determined the adenosine diphosphate-induced platelet reactivity before and immediately after exercise testing. Additionally, we analysed maximal exercise capacity and an electrocardiogram. Further, we assessed chromogranin A and P-selectin levels and platelet counts. © Georg Thieme Verlag KG Stuttgart · New York.

Exercise Testing Reveals Everyday Physical Challenges of Bariatric Surgery Candidates.

PubMed

Creel, David B; Schuh, Leslie M; Newton, Robert L; Stote, Joseph J; Cacucci, Brenda M

2017-12-01

Few studies have quantified cardiorespiratory fitness among individuals seeking bariatric surgery. Treadmill testing allows researchers to determine exercise capacity through metabolic equivalents. These findings can assist clinicians in understanding patients' capabilities to carry out various activities of daily living. The purpose of this study was to determine exercise tolerance and the variables associated with fitness, among individuals seeking bariatric surgery. Bariatric surgery candidates completed submaximal treadmill testing and provided ratings of perceived exertion. Each participant also completed questionnaires related to history of exercise, mood, and perceived barriers/benefits of exercise. Over half of participants reported that exercise was "hard to very hard" before reaching 70% of heart rate reserve, and one-third of participants reported that exercise was "moderately hard" at less than 3 metabolic equivalents (light activity). Body mass index and age accounted for the majority of the variance in exercise tolerance, but athletic history, employment status, and perceived health benefits also contributed. Perceived benefit scores were higher than barrier scores. Categories commonly used to describe moderate-intensity exercise (3-6 metabolic equivalents) do not coincide with perceptions of intensity among many bariatric surgery candidates, especially those with a body mass index of 50 or more.

Musical Agency during Physical Exercise Decreases Pain.

PubMed

Fritz, Thomas H; Bowling, Daniel L; Contier, Oliver; Grant, Joshua; Schneider, Lydia; Lederer, Annette; Höer, Felicia; Busch, Eric; Villringer, Arno

2017-01-01

Objectives: When physical exercise is systematically coupled to music production, exercisers experience improvements in mood, reductions in perceived effort, and enhanced muscular efficiency. The physiology underlying these positive effects remains unknown. Here we approached the investigation of how such musical agency may stimulate the release of endogenous opioids indirectly with a pain threshold paradigm. Design: In a cross-over design we tested the opioid-hypothesis with an indirect measure, comparing the pain tolerance of 22 participants following exercise with or without musical agency. Method: Physical exercise was coupled to music by integrating weight-training machines with sensors that control music-synthesis in real time. Pain tolerance was measured as withdrawal time in a cold pressor test. Results: On average, participants tolerated cold pain for ~5 s longer following exercise sessions with musical agency. Musical agency explained 25% of the variance in cold pressor test withdrawal times after factoring out individual differences in general pain sensitivity. Conclusions: This result demonstrates a substantial pain reducing effect of musical agency in combination with physical exercise, probably due to stimulation of endogenous opioid mechanisms. This has implications for exercise endurance, both in sports and a multitude of rehabilitative therapies in which physical exercise is effective but painful.

Musical Agency during Physical Exercise Decreases Pain

PubMed Central

Fritz, Thomas H.; Bowling, Daniel L.; Contier, Oliver; Grant, Joshua; Schneider, Lydia; Lederer, Annette; Höer, Felicia; Busch, Eric; Villringer, Arno

2018-01-01

Objectives: When physical exercise is systematically coupled to music production, exercisers experience improvements in mood, reductions in perceived effort, and enhanced muscular efficiency. The physiology underlying these positive effects remains unknown. Here we approached the investigation of how such musical agency may stimulate the release of endogenous opioids indirectly with a pain threshold paradigm. Design: In a cross-over design we tested the opioid-hypothesis with an indirect measure, comparing the pain tolerance of 22 participants following exercise with or without musical agency. Method: Physical exercise was coupled to music by integrating weight-training machines with sensors that control music-synthesis in real time. Pain tolerance was measured as withdrawal time in a cold pressor test. Results: On average, participants tolerated cold pain for ~5 s longer following exercise sessions with musical agency. Musical agency explained 25% of the variance in cold pressor test withdrawal times after factoring out individual differences in general pain sensitivity. Conclusions: This result demonstrates a substantial pain reducing effect of musical agency in combination with physical exercise, probably due to stimulation of endogenous opioid mechanisms. This has implications for exercise endurance, both in sports and a multitude of rehabilitative therapies in which physical exercise is effective but painful. PMID:29387030

[Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test].

PubMed

Pimentel, Alan Santos; Alves, Eduardo da Silva; Alvim, Rafael de Oliveira; Nunes, Rogério Tasca; Costa, Carlos Magno Amaral; Lovisi, Júlio Cesar Moraes; Perrout de Lima, Jorge Roberto

2010-05-01

The 4-second exercise test (T4s) evaluates the cardiac vagal tone during the initial heart rate (HR) transient at sudden dynamic exercise, through the identification of the cardiac vagal index (CVI) obtained from the electrocardiogram (ECG). To evaluate the use of the Polar S810 heart rate monitor (HRM) as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. In this study, 49 male individuals (25 +/- 20 years, 176 +/-12 cm, 74 +/- 6 kg) underwent the 4-second exercise test. The RR intervals were recorded simultaneously by ECG and HRM. We calculated the mean and the standard deviation of the last RR interval of the pre-exercise period, or of the first RR interval of the exercise period, whichever was longer (RRB), of the shortest RR interval of the exercise period (RRC), and of the CVI obtained by ECG and HRM. We used the Student t-test for dependent samples (p < or 0.05) to test the significance of the differences between means. To identify the correlation between the ECG and the HRM, we used the linear regression to calculate the Pearson's correlation coefficient and the strategy proposed by Bland and Altman. Linear regression showed r(2) of 0.9999 for RRB, 0.9997 for RRC, and 0.9996 for CVI. Bland e Altman strategy presented standard deviation of 0.92 ms for RRB, 0.86 ms for RRC, and 0.002 for CVI. Polar S810 HRM was more efficient in the application of T4s compared to the ECG.

The effect of exercise on physical fitness and quality of life in postmenopausal women.

PubMed

Teoman, Nursen; Ozcan, Ayşe; Acar, Berrin

2004-01-20

This study was designed to determine the effect of exercise on the physical fitness level and quality of life in postmenopausal women. 81 volunteer postmenopausal women who entered the menopause naturally and have been taking hormone replacement treatment (HRT) were divided randomly into two groups: exercise (n=41) and control (n=40). Physical fitness tests and the Nottingham Health Profile (NHP) were used to assess physical fitness and quality of life in both groups, both before and after 6 weeks. The study group participated in an exercise programme, which was composed of sub-maximal aerobic exercises for a 6-week period 3 times a week. The statistical analyses were done by paired samples t-test and independent samples t-test. At the end of 6 weeks exercise period, when the two groups were compared after the exercise period, we found statistically significant differences in strength, endurance, flexibility and balance parameters in the exercise group (P<0.05). There was also a statistically significant change in the exercise group for the NHP indicating an improvement in the quality of life (P<0.05). In this study, it was concluded that the fitness level and quality of life on postmenopausal women could be improved by a regular and controlled exercise programme of 6 weeks.

Effects of a renal rehabilitation exercise program in patients with CKD: a randomized, controlled trial.

PubMed

Rossi, Ana P; Burris, Debra D; Lucas, F Leslie; Crocker, Gail A; Wasserman, James C

2014-12-05

Patients with CKD have a high prevalence of cardiovascular disease associated with or exacerbated by inactivity. This randomized, controlled study investigated whether a renal rehabilitation exercise program for patients with stages 3 or 4 CKD would improve their physical function and quality of life. In total, 119 adults with CKD stages 3 and 4 were randomized, and 107 of these patients proceeded to usual care or the renal rehabilitation exercise intervention consisting of usual care plus guided exercise two times per week for 12 weeks (24 sessions). Physical function was determined by three well established performance-based tests: 6-minute walk test, sit-to-stand test, and gait-speed test. Health-related quality of life was assessed by the RAND 36-Item Short Form Health Survey. At baseline, no differences in self-reported level of activity, 6-minute walk test, and sit-to-stand test scores were observed between the usual care (n=48) and renal rehabilitation exercise (n=59) groups, although baseline gait-speed test score was higher in the renal rehabilitation exercise group (P<0.001). At follow-up, the renal rehabilitation exercise group but not the usual care group showed significant improvements in the 6-minute walk test (+210.4±266.0 ft [19% improvement] versus -10±219.9 ft; P<0.001), the sit-to-stand test (+26.9±27% of age prediction [29% improvement] versus +0.7±12.1% of age prediction; P<0.001), and the RAND-36 physical measures of role functioning (P<0.01), physical functioning (P<0.01), energy/fatigue levels (P=0.01), and general health (P=0.03) and mental measure of pain scale (P=0.04). The renal rehabilitation exercise regimen was generally well tolerated. A 12-week/24-session renal rehabilitation exercise program improved physical capacity and quality of life in patients with CKD stages 3 and 4. Longer follow-up is needed to determine if these findings will translate into decreased mortality rates. Copyright © 2014 by the American Society of Nephrology.

[Silent myocardial ischemia and exercise-induced arrhythmia detected by the exercise test in the total health promotion plan (THP)].

PubMed

Iwane, M; Shibe, Y; Itoh, K; Kinoshita, F; Kanagawa, Y; Kobayashi, M; Mugitani, K; Ohta, M; Ohata, H; Yoshikawa, A; Ikuta, Z; Nakamura, Y; Mohara, O

2001-03-01

We investigated the prevalence and characteristics of ischemic heart disease especially silent myocardial ischemia (SMI) and arrhythmia in need of careful observation in the exercise stress tests in the Total Health Promotion Plan (THP), which was conducted between 1994-96 for the purpose of measuring cardiopulmonary function. All workers (n = 4,918, 4,426 males) aged 18-60 yr old in an occupational field were studied. Exercise tests with an ergometer were performed by the LOPS protocol, in which the maximal workload was set up as a presumed 70-80% maximal oxygen intake, or STEP (original multistage protocol). ECG changes were evaluated with a CC5 lead. Two hundred and fifteen people refused the study because of a common cold, lumbago and so on. Of 4,703 subjects, 17 with abnormal rest ECG and 19 with probable anginal pain were excluded from the exercise tests. Of 4,667 who underwent the exercise test, 37 (0.79%) had ischemic ECG change, and 155 (3.32%) had striking arrhythmia. These 228 subjects then did a treadmill exercise test with Bruce protocol. Twenty-two (0.47% of 4,703) showed positive ECG change, 9 (0.19%) of 22 had abnormal findings on a 201Tl scan. 8 (0.17%) were diagnosed as SMI (Cohn I), in which the prevalence of hypertension, hyperlipidemia, diabetes mellitus, smoker and positive familial history of ischemic heart disease was greater than that of all subjects. In a 15-30 month follow up, none has developed cardiac accidents. Exercise-induced arrhythmia was detected in 11 (0.23%) subjects. Four were non-sustained ventricular tachycardia without any organic disease, 4 were ventricular arrhythmia based on cardiomyopathy detected by echocardiography, 2 were atrial fibrillation and another was WPW syndrome. It is therefore likely that the ergometer exercise test in THP was effective in preventing sudden death caused by ischemic heart disease or striking arrhythmia.

Telehealth technologies and applications for terrorism response: a report of the 2002 coastal North Carolina domestic preparedness training exercise.

PubMed

Simmons, Scott C; Murphy, Timothy A; Blanarovich, Adrian; Workman, Florence T; Rosenthal, David A; Carbone, Matthew

2003-01-01

Effective response to natural or man-made disasters (i.e., terrorism) is predicated on the ability to communicate among the many organizations involved. Disaster response exercises enable disaster planners and responders to test procedures and technologies and incorporate the lessons learned from past disasters or exercises. On May 31 and June 1, 2002, one such exercise event took place at the Camp Lejeune Marine Corps Base in Jacksonville, North Carolina. During the exercise, East Carolina University tested: (1) in-place Telehealth networks and (2) rapidly deployable communications, networking, and data collection technologies such as satellite communications, local wireless networking, on-scene video, and clinical and environmental data acquisition and telemetry. Exercise participants included local, county, state, and military emergency medical services (EMS), emergency management, specialized response units, and local fire and police units. The technologies and operations concepts tested at the exercise and recommendations for using telehealth to improve disaster response are described.

Telehealth Technologies and Applications for Terrorism Response: A Report of the 2002 Coastal North Carolina Domestic Preparedness Training Exercise

PubMed Central

Simmons, Scott C.; Murphy, Timothy A.; Blanarovich, Adrian; Workman, Florence T.; Rosenthal, David A.; Carbone, Matthew

2003-01-01

Effective response to natural or man-made disasters (i.e., terrorism) is predicated on the ability to communicate among the many organizations involved. Disaster response exercises enable disaster planners and responders to test procedures and technologies and incorporate the lessons learned from past disasters or exercises. On May 31 and June 1, 2002, one such exercise event took place at the Camp Lejeune Marine Corps Base in Jacksonville, North Carolina. During the exercise, East Carolina University tested: (1) in-place Telehealth networks and (2) rapidly deployable communications, networking, and data collection technologies such as satellite communications, local wireless networking, on-scene video, and clinical and environmental data acquisition and telemetry. Exercise participants included local, county, state, and military emergency medical services (EMS), emergency management, specialized response units, and local fire and police units. The technologies and operations concepts tested at the exercise and recommendations for using telehealth to improve disaster response are described. PMID:12595406

Effect of weight loss, exercise, or both on cognition and quality of life in obese older adults1234

PubMed Central

Napoli, Nicola; Shah, Krupa; Waters, Debra L; Sinacore, David R; Qualls, Clifford; Villareal, Dennis T

2014-01-01

Background: Obesity impairs cognition and health-related quality of life (HRQOL) in older adults; however, the appropriate treatment of obese older adults remains controversial. Objective: The objective was to determine the independent and combined effects of weight loss and exercise on cognition, mood, and HRQOL in obese older adults. Design: One hundred seven frail, obese older adults were randomly assigned to a control, weight-management (diet), exercise, or weight-management-plus-exercise (diet-exercise) group for 1 y. In this secondary analysis, main outcomes were Modified Mini-Mental State Examination (3MS) and total Impact of Weight on Quality of Life-Lite (IWQOL) scores. Other outcomes included Word Fluency Test, Trail Making Test Parts A and B, and Geriatric Depression Scale (GDS) scores. Results: Scores on the 3MS improved more in the diet (mean ± SE: 1.7 ± 0.4), exercise (2.8 ± 0.4), and diet-exercise (2.9 ± 0.4) groups than in the control group (0.1 ± 0.4) (between-group P = 0.0001–0.04); scores in the diet-exercise group improved more than in the diet group but not more than in the exercise group. Scores on the Word Fluency Test improved more in the exercise (4.1 ± 0.8) and diet-exercise (4.2 ± 0.7) groups than in the control group (−0.8 ± 0.8; both P = 0.001). For the Trail Making Test Part A, scores in the diet-exercise group (−11.8 ± 1.9) improved more than in the control group (−0.8 ± 1.9) (P = 0.001); a similar finding was observed for the Trail Making Test Part B. Scores on the IWQOL improved more in the diet (7.6 ± 1.6), exercise (10.1 ± 1.6), and diet-exercise (14.0 ± 1.4) groups than in the control group (0.3 ± 1.6) (P = 0.0001–0.03); scores in the diet-exercise group improved more than in the diet group but not more than in the exercise group. In the diet-exercise group, peak oxygen consumption and strength changes were independent predictors of 3MS changes; weight and strength changes were independent predictors of IWQOL changes. GDS scores did not change. Conclusions: Weight loss and exercise each improve cognition and HRQOL, but their combination may provide benefits similar to exercise alone. These findings could inform practice guidelines with regard to optimal treatment strategies for obese older adults. This trial was registered atclinicaltrials.govas NCT00146107. PMID:24787497

Effect of Capacitive and Resistive electric transfer on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise.

PubMed

Yokota, Yuki; Sonoda, Takuya; Tashiro, Yuto; Suzuki, Yusuke; Kajiwara, Yu; Zeidan, Hala; Nakayama, Yasuaki; Kawagoe, Mirei; Shimoura, Kanako; Tatsumi, Masataka; Nakai, Kengo; Nishida, Yuichi; Bito, Tsubasa; Yoshimi, Soyoka; Aoyama, Tomoki

2018-05-01

[Purpose] This study aimed to clarify the effects of Capacitive and Resistive electric transfer (CRet) on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise. [Subjects and Methods] Twenty-two healthy males were assigned into either the CRet (n=11) or control (n=11) group. Fatiguing exercise and CRet intervention were applied at the quadriceps muscle of the participants' dominant legs. The Ely test, pelvic tilt, lumbar lordosis, and superficial temperature were measured before and after exercise and for 30 minutes after intervention. Statistical analysis was performed using one-way analysis of variance, with Tukey's post-hoc multiple comparison test to clarify within-group changes and Student's t-test to clarify between-group differences. [Results] The Ely test and pelvic tilt were significantly different in both groups after exercise, but there was no difference in the CRet group after intervention. Superficial temperature significantly increased in the CRet group for 30 minutes after intervention, in contrast to after the exercise and intervention in the control group. There was no significant between-group difference at any timepoint, except in superficial temperature. [Conclusion] CRet could effectively improve muscle flexibility and lumbopelvic alignment after fatiguing exercise.

Effect of Capacitive and Resistive electric transfer on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise

PubMed Central

Yokota, Yuki; Sonoda, Takuya; Tashiro, Yuto; Suzuki, Yusuke; Kajiwara, Yu; Zeidan, Hala; Nakayama, Yasuaki; Kawagoe, Mirei; Shimoura, Kanako; Tatsumi, Masataka; Nakai, Kengo; Nishida, Yuichi; Bito, Tsubasa; Yoshimi, Soyoka; Aoyama, Tomoki

2018-01-01

[Purpose] This study aimed to clarify the effects of Capacitive and Resistive electric transfer (CRet) on changes in muscle flexibility and lumbopelvic alignment after fatiguing exercise. [Subjects and Methods] Twenty-two healthy males were assigned into either the CRet (n=11) or control (n=11) group. Fatiguing exercise and CRet intervention were applied at the quadriceps muscle of the participants’ dominant legs. The Ely test, pelvic tilt, lumbar lordosis, and superficial temperature were measured before and after exercise and for 30 minutes after intervention. Statistical analysis was performed using one-way analysis of variance, with Tukey’s post-hoc multiple comparison test to clarify within-group changes and Student’s t-test to clarify between-group differences. [Results] The Ely test and pelvic tilt were significantly different in both groups after exercise, but there was no difference in the CRet group after intervention. Superficial temperature significantly increased in the CRet group for 30 minutes after intervention, in contrast to after the exercise and intervention in the control group. There was no significant between-group difference at any timepoint, except in superficial temperature. [Conclusion] CRet could effectively improve muscle flexibility and lumbopelvic alignment after fatiguing exercise. PMID:29765189

Influence of work clothing on physiological responses and performance during treadmill exercise and the Wildland Firefighter Pack Test.

PubMed

Phillips, Devin B; Ehnes, Cameron M; Welch, Bradley G; Lee, Lauren N; Simin, Irina; Petersen, Stewart R

2018-04-01

This study investigated physiological responses and performance during three separate exercise challenges (Parts I, II, and III) with wildland firefighting work clothing ensemble (boots and coveralls) and a 20.4 kg backpack in four conditions: U-EX (no pack, exercise clothing); L-EX (pack, exercise clothing); U-W (no pack, work clothing); and, L-W (pack and work clothing). Part I consisted of randomly-ordered graded exercise tests, on separate days, in U-EX, L-EX and L-W conditions. Part II consisted of randomly-ordered bouts of sub-maximal treadmill exercise in the four conditions. In Part III, subjects completed, in random-order on separate days, 4.83 km Pack Tests in L-EX or L-W conditions. In Part I, peak oxygen uptake was reduced (p < .05) in L-W. In Part II, mass-specific oxygen uptake was significantly higher in both work clothing conditions. In Part III, Pack Test time was slower (p < .05) in L-W. These results demonstrate the negative impact of work clothing and load carriage on physiological responses to exercise and performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reliability of Strength Testing using the Advanced Resistive Exercise Device and Free Weights

NASA Technical Reports Server (NTRS)

English, Kirk L.; Loehr, James A.; Laughlin, Mitzi A.; Lee, Stuart M. C.; Hagan, R. Donald

2008-01-01

The Advanced Resistive Exercise Device (ARED) was developed for use on the International Space Station as a countermeasure against muscle atrophy and decreased strength. This investigation examined the reliability of one-repetition maximum (1RM) strength testing using ARED and traditional free weight (FW) exercise. Methods: Six males (180.8 +/- 4.3 cm, 83.6 +/- 6.4 kg, 36 +/- 8 y, mean +/- SD) who had not engaged in resistive exercise for at least six months volunteered to participate in this project. Subjects completed four 1RM testing sessions each for FW and ARED (eight total sessions) using a balanced, randomized, crossover design. All testing using one device was completed before progressing to the other. During each session, 1RM was measured for the squat, heel raise, and deadlift exercises. Generalizability (G) and intraclass correlation coefficients (ICC) were calculated for each exercise on each device and were used to predict the number of sessions needed to obtain a reliable 1RM measurement (G . 0.90). Interclass reliability coefficients and Pearson's correlation coefficients (R) also were calculated for the highest 1RM value (1RM9sub peak)) obtained for each exercise on each device to quantify 1RM relationships between devices.

Clinical test responses to different orthoptic exercise regimes in typical young adults

PubMed Central

Horwood, Anna; Toor, Sonia

2014-01-01

Purpose The relative efficiency of different eye exercise regimes is unclear, and in particular the influences of practice, placebo and the amount of effort required are rarely considered. This study measured conventional clinical measures following different regimes in typical young adults. Methods A total of 156 asymptomatic young adults were directed to carry out eye exercises three times daily for 2 weeks. Exercises were directed at improving blur responses (accommodation), disparity responses (convergence), both in a naturalistic relationship, convergence in excess of accommodation, accommodation in excess of convergence, and a placebo regime. They were compared to two control groups, neither of which were given exercises, but the second of which were asked to make maximum effort during the second testing. Results Instruction set and participant effort were more effective than many exercises. Convergence exercises independent of accommodation were the most effective treatment, followed by accommodation exercises, and both regimes resulted in changes in both vergence and accommodation test responses. Exercises targeting convergence and accommodation working together were less effective than those where they were separated. Accommodation measures were prone to large instruction/effort effects and monocular accommodation facility was subject to large practice effects. Conclusions Separating convergence and accommodation exercises seemed more effective than exercising both systems concurrently and suggests that stimulation of accommodation and convergence may act in an additive fashion to aid responses. Instruction/effort effects are large and should be carefully controlled if claims for the efficacy of any exercise regime are to be made. PMID:24471739

[Study on the molecular-epidemiological characteristics of HIV-1 in Shenzhen, 1992-2008].

PubMed

Zhao, Guang-lu; Yu, Wei; Zhang, Juan-juan; Chen, Lin; Feng, Tie-jian; Wang, Feng; Hong, Fu-chang; Wang, Xiao-hui; Li, Qing

2012-01-01

To investigate the epidemiological characteristics of HIV-1 subtype in Shenzhen from 1992 to 2008. 489 HIV-1 positive plasma samples were collected from 1992 to 2008 in Shenzhen. HIV-1 env genes were amplified by nested-PCR from RNA. Phylogenetic analysis was performed on data regarding the nucleotide sequence. A total of 464 sequences were amplified and genotyped. Data from this study revealed that CRF01_AE was a predominant HIV-1 subtype in Shenzhen (64.4%, 299/464), followed by subtypes CRF_BC (17.5%, 81/464), B' (14.7%, 68/464) and B (2.4%, 11/464). Subtype C (0.4%, 2/464), A1 (0.2%, 1/464), CRF02_AG (0.2%, 1/464) and CRF06_cpx (0.2%, 1/464) were also prevalent in Shenzhen. CRF01_AE and CRF_BC were predominant among heterosexuals, homosexuals and injection drug users, while B' was predominant among blood donors. Results from phylogenetic tree analysis showed that some of the HIV-1 clusters had been defined in CRF01_AE strains at different time or groups with different transmission routes. Cross-infections were also seen. CRF01_AE was the predominant HIV-1 subtype in Shenzhen while CRF_BC, B, B', C, A1, CRF02_AG and a small amount of CRF06_cpx or recombinant subtypes were prevalent in this city. Different subtypes showed great variation in the process of epidemics.

Prescribing water-based exercise from treadmill and arm ergometry in cardiac patients.

PubMed

Fernhall, B; Manfredi, T G; Congdon, K

1992-01-01

This study investigated the appropriateness of prescribing upright water-based exercise from treadmill and arm ergometry in uncomplicated, trained patients with cardiovascular disease (CVD) who were accustomed to water-based activities. Ten male patients with established CVD (mean age 59.4 +/- 8.7 yr) underwent maximal treadmill and arm ergometry in randomized counterbalanced order (half of the patients completed the treadmill test first and the other half completed the arm ergometer test first). Electrocardiographic (ECG), rating of perceived exertion (RPE), and oxygen uptake (VO2) measurements were made during both tests. Patients performed upright water-based exercise at 60, 70, and 80% of their maximal treadmill heart rate for 6 min at each intensity in a heated pool with a water temperature of 28-30 degrees C. They also performed an easy tethered swim, defined as performing at a comfortable exercise intensity, eliciting a heart rate of 86% of the treadmill maximum. VO2 and RPE were collected for all water-based exercise. To compare the RPE and VO2 between water-based, treadmill, and arm ergometry exercise, individual regression equations were constructed between heart rate, VO2, and RPE for both treadmill and arm ergometry tests. VO2 and RPE were then compared at the same heart rates between the three exercise modes. At 60% intensity, treadmill exercise exhibited a higher VO2 than water-based and arm ergometry exercise (P less than 0.05) but similar RPE. At 70%, treadmill exercise still yielded higher VO2, but also lower RPE than (P less than 0.05) and arm ergometry exercise (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Symptom-limited exercise testing causes sustained diastolic dysfunction in patients with coronary disease and low effort tolerance.

PubMed

Fragasso, G; Benti, R; Sciammarella, M; Rossetti, E; Savi, A; Gerundini, P; Chierchia, S L

1991-05-01

Exercise stress testing is routinely used for the noninvasive assessment of coronary artery disease and is considered a safe procedure. However, the provocation of severe ischemia might potentially cause delayed recovery of myocardial function. To investigate the possibility that maximal exercise testing could induce prolonged impairment of left ventricular function, 15 patients with angiographically proved coronary disease and 9 age-matched control subjects with atypical chest pain and normal coronary arteries were studied. Radionuclide ventriculography was performed at rest, at peak exercise, during recovery and 2 and 7 days after exercise. Ejection fraction, peak filling and peak emptying rates and left ventricular wall motion were analyzed. All control subjects had a normal exercise test at maximal work loads and improved left ventricular function on exercise. Patients developed 1 mm ST depression at 217 +/- 161 s at a work load of 70 +/- 30 W and a rate-pressure product of 18,530 +/- 4,465 mm Hg x beats/min. Although exercise was discontinued when angina or equivalent symptoms occurred, in all patients diagnostic ST depression (greater than or equal to 1 mm) developed much earlier than symptoms. Predictably, at peak exercise patients showed a decrease in ejection fraction and peak emptying and filling rates. Ejection fraction and peak emptying rate normalized within the recovery period, whereas peak filling rate remained depressed throughout recovery (p less than 0.002) and was still reduced 2 days after exercise (p less than 0.02). In conclusion, in patients with severe impairement of coronary flow reserve, maximal exercise may cause sustained impairement of diastolic function.(ABSTRACT TRUNCATED AT 250 WORDS)

AMPK and PPARδ agonists are exercise mimetics

PubMed Central

Narkar, Vihang A.; Downes, Michael; Yu, Ruth T.; Embler, Emi; Wang, Yong-Xu; Banayo, Ester; Mihaylova, Maria M.; Nelson, Michael C.; Zou, Yuhua; Juguilon, Henry; Kang, Heonjoong; Shaw, Reuben; Evans, Ronald M.

2008-01-01

SUMMARY The benefits of endurance exercise on general health make it desirable to identify orally active agents that would mimic or potentiate the effects of exercise to treat metabolic diseases. Although certain natural compounds, such as reseveratrol, have endurance-enhancing activities, their exact metabolic targets remain elusive. We therefore tested the effect of pathway-specific drugs on endurance capacities of mice in a treadmill running test. We found that PPARβ/δ agonist and exercise training synergistically increase oxidative myofibers and running endurance in adult mice. Because training activates AMPK and PGC1α, we then tested whether the orally active AMPK agonist AICAR might be sufficient to overcome the exercise requirement. Unexpectedly, even in sedentary mice, 4 weeks of AICAR treatment alone induced metabolic genes and enhanced running endurance by 44%. These results demonstrate that AMPK-PPARδ pathway can be targeted by orally active drugs to enhance training adaptation or even to increase endurance without exercise. PMID:18674809

Effect of bed rest and exercise on body balance

NASA Technical Reports Server (NTRS)

Haines, R. F.

1974-01-01

A battery of 11 body balance tests was administered to 7 men before and after 14 days of bedrest. Seven men who had not undergone bed rest served as controls. During bed rest, each subject underwent daily either isotonic, isometric, or no leg exercise. The results showed that, for the bed-rested no exercise, isotonic exercise, and isometric exercise groups, 2 weeks of bed rest produces significant body balance decrements on 3, 4, and 5 of the 11 tests, respectively. Daily leg exercise did not prevent the debilitating effects of bed rest on body balance. After bed rest, balance skill was relearned rapidly so that in most tests, performance had reached prebed-rest levels by the third recovery day. These data suggest that balance impairment is not due to loss of muscular strength in the legs but, perhaps, to a bed-rest-related change in the neurally coded information to postural control centers.

Repeatability and responsiveness of exercise tests in pulmonary arterial hypertension.

PubMed

Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Bonnet, Sébastien; Maltais, François; Saey, Didier; Provencher, Steeve

2013-08-01

Exercise tolerance in pulmonary arterial hypertension (PAH) is most commonly assessed by the 6-min walk test (6MWT). Whether endurance exercise tests are more responsive than the 6MWT remains unknown. 20 stable PAH patients (mean±sd age 53±15 years and mean pulmonary arterial pressure 44±16 mmHg) already on PAH monotherapy completed the 6MWT, the endurance shuttle walk test (ESWT) and the cycle endurance test (CET) before and after the addition of sildenafil citrate 20 mg three times daily or placebo for 28 days in a randomised double-blind crossover setting. Pre- or post-placebo tests were used to assess repeatability of each exercise test, whereas pre- or post-sildenafil citrate tests were used to assess their responsiveness. Sildenafil citrate led to placebo-corrected changes in exercise capacity of 18±25 m (p = 0.02), 58±235 s (p = 0.58) and 29±77 s (p = 0.09) for the 6MWT, the ESWT and the CET, respectively. The 6MWT was associated with a lower coefficient of variation between repeated measures (3% versus 18% versus 13%), resulting in a higher standardised response mean compared with endurance tests (0.72, 0.25 and 0.38 for the 6MWT, the ESWT and the CET, respectively). The 6MWT had the best ability to capture changes in exercise capacity when sildenafil citrate was combined with patients' baseline monotherapy, supporting its use as an outcome measure in PAH.

Eucapnic Voluntary Hyperventilation to Detect Exercise-Induced Bronchoconstriction in Cystic Fibrosis.

PubMed

Kirkby, Stephen E; Hayes, Don; Parsons, Jonathan P; Wisely, Clayton E; Kopp, Ben; McCoy, Karen S; Mastronarde, John G

2015-10-01

Exercise-induced bronchoconstriction (EIB) has not been well studied in cystic fibrosis (CF), and eucapnic voluntary hyperventilation (EVH) testing has not been used as an objective assessment of EIB in CF to date. A prospective cohort pilot study was completed where standard EVH testing was completed by 10 CF patients with forced expiratory volume in 1 s (FEV1) ≥70% of predicted. All patients also completed a cardiopulmonary exercise test (CPET) with pre- and post-CPET spirometry as a comparative method of detecting EIB. No adverse events occurred with EVH testing. A total of 20% (2/10) patients were diagnosed with EIB by means of EVH. Both patients had clinical symptoms consistent with EIB. No patient had a CPET-based exercise challenge consistent with EIB. EVH testing was safe and effective in the objective assessment for EIB in patients with CF who had well-preserved lung function. It may be a more sensitive method of detecting EIB then exercise challenge.

Oxygen uptake during peak graded exercise and single-stage fatigue tests of wheelchair propulsion in manual wheelchair users and the able-bodied.

PubMed

Keyser, R E; Rodgers, M M; Gardner, E R; Russell, P J

1999-10-01

To determine if a single-stage, submaximal fatigue test on a wheelchair ergometer would result in higher than expected energy expenditure. An experimental survey design contrasting physiologic responses during peak graded exercise tests and fatigue tests. A rehabilitation science laboratory that included a prototypical wheelchair ergometer, open-circuit spirometry system, and heart rate monitor. Nine able-bodied non-wheelchair users (the NWC group: 6 men and 3 women, mean +/- SD age 30 +/- 7yrs) and 15 manual wheelchair users (the WC group: 12 men and 3 women, age 40 +/- 9yrs, time in wheelchair 16 +/- 9yrs). No subject had any disease, medication regimen, or upper body neurologic, orthopedic, or other condition that would limit wheelchair exercise. Peak oxygen uptake (VO2) for graded exercise testing and during fatigue testing, using a power output corresponding to 75% peak aerobic capacity on graded exercise test. In the WC group, VO2 at 6 minutes of fatigue testing was not significantly different from peak VO2. In the NWC group, VO2 was similar to the expected level throughout fatigue testing. Energy expenditure was higher than expected in the WC group but not in the NWC group. Fatigue testing may provide a useful evaluation of cardiorespiratory status in manual wheelchair users.

An Example for Integrated Gas Turbine Engine Testing and Analysis Using Modeling and Simulation

DTIC Science & Technology

2006-12-01

USAF Academy in a joint test and analysis effort of the F109 turbofan engine. This process uses a swirl investigation as a vehicle to exercise and...test and analysis effort of the F109 turbofan engine. This process uses a swirl investigation as a vehicle to exercise and demonstrate the approach...test and analysis effort of the F109 turbofan engine, an effort which uses a swirl investigation as a vehicle to exercise and demonstrate the

Orbital Fitness: An Overview of Space Shuttle Cardiopulmonary Exercise Physiology Findings

NASA Technical Reports Server (NTRS)

Moore, Alan D.

2011-01-01

Limited observations regarding the cardiopulmonary responses to aerobic exercise had been conducted during short-duration spaceflight before the Space Shuttle program. This presentation focuses on the findings regarding changes observed in the cardiopulmonary exercise responses during and following Shuttle flights. During flight, maximum oxygen uptake (VO2max) remained unchanged as did the maximum work rate achievable during cycle exercise testing conducted during the last full flight day. Immediately following flight, the ubiquitous finding, confirmed by investigations conducted during the Spacelab Life Sciences missions 1 and 2 and by NASA Detailed Supplemental Objective studies, indicated that VO2max was reduced; however, the reduction in VO2max was transient and returned to preflight levels within 7 days following return. Studies regarding the influence of aerobic exercise countermeasures performed during flight on postflight performance were mostly limited to the examination of the heart rate (HR) response to submaximal exercise testing on landing day. These studies revealed that exercise HR was elevated in individuals who performed little to no exercise during their missions as compared to individuals who performed regular exercise. In addition, astronauts who performed little to no aerobic exercise during flight demonstrated an increased HR and lowered pulse pressure response to the standard stand test on landing day, indicating a decrease in orthostatic function in these individuals. With regard to exercise modality, four devices were examined during the Shuttle era: two treadmills, a cycle ergometer, and a rowing device. Although there were limited investigations regarding the use of these devices for exercise training aboard the Shuttle, there was no clear consensus reached regarding which proved to be a "superior" device. Each device had a unique operational or physiologic limitation associated with its use. In conclusion, exercise research conducted during the Shuttle Program demonstrated that attenuation of postflight deconditioning was possible through use of exercise countermeasures and the Shuttle served as a test bed for equipment destined for use on the International Space Station. Learning Objective: Overview of the Space Shuttle Program research results related to aerobic capacity and performance, including what was learned from research and effectiveness of exercise countermeasures.

Physiologic and Endocrine Correlates of Overweightness in African Americans and Caucasians

DTIC Science & Technology

2009-03-27

aerobic graded exercise test (VO2 max test ) on a treadmill ( Philips StressVue Exercise Stress Testing System with Trackmaster Full Vision Inc...Pediatrics, 118 (6), 2434-42. Wang, J., Thornton, J.C., Bari, S., Williamson, B., Gallagher, D., Heymsfield, S.B., Horlick, M., Kotler , D...on a treadmill ( Philips StressVue Exercise Stress System, Trackmaster Full Vision Inc. Treadmill; Waltham, MA) to assess cardiovascular fitness. The

Exercise Self-Efficacy Moderates the Relation between Anxiety Sensitivity and Body Mass Index and Exercise Tolerance in Treatment-Seeking Smokers

PubMed Central

Farris, Samantha G.; Davis, Michelle L.; Rosenfield, David; Kauffman, Brooke Y.; Baird, Scarlett O.; Powers, Mark B.; Otto, Michael W.; Marcus, Bess H.; Church, Timothy S.; Smits, Jasper A. J.; Zvolensky, Michael J.

2016-01-01

There is little known about factors that contribute to the comorbidity of cigarette smoking and obesity. The current study sought to test whether exercise self-efficacy moderated the relation between anxiety sensitivity (fear of internal sensations) and BMI and exercise tolerance among cigarette smokers. Smokers (n = 72; 50% female; Mcpd = 19.3, SD = 10.65) were recruited to participate in a smoking cessation treatment trial. During medical screen, we measured weight, height, and exercise tolerance (functional capacity) employing a standardized maximal exercise testing protocol. After adjusting for participant sex and cigarettes per day, exercise self-efficacy moderated the association between anxiety sensitivity and BMI, such that the positive association between anxiety sensitivity and BMI was significantly stronger when exercise self-efficacy was low. The same pattern of results emerged for exercise tolerance. Exercise self-efficacy moderated the association between anxiety sensitivity and exercise tolerance, such that the negative association between anxiety sensitivity and exercise tolerance was significantly stronger when exercise self-efficacy was low. Among smokers, anxiety sensitivity may be a risk variable that, directly and indirectly in the context of low self-efficacy for exercise, causes or maintains higher body weight and lower exercise tolerance. PMID:27725844

Exercise Self-Efficacy Moderates the Relation between Anxiety Sensitivity and Body Mass Index and Exercise Tolerance in Treatment-Seeking Smokers.

PubMed

Farris, Samantha G; Davis, Michelle L; Rosenfield, David; Kauffman, Brooke Y; Baird, Scarlett O; Powers, Mark B; Otto, Michael W; Marcus, Bess H; Church, Timothy S; Smits, Jasper A J; Zvolensky, Michael J

2016-03-01

There is little known about factors that contribute to the comorbidity of cigarette smoking and obesity. The current study sought to test whether exercise self-efficacy moderated the relation between anxiety sensitivity (fear of internal sensations) and BMI and exercise tolerance among cigarette smokers. Smokers ( n = 72; 50% female; M cpd = 19.3, SD = 10.65) were recruited to participate in a smoking cessation treatment trial. During medical screen, we measured weight, height, and exercise tolerance (functional capacity) employing a standardized maximal exercise testing protocol. After adjusting for participant sex and cigarettes per day, exercise self-efficacy moderated the association between anxiety sensitivity and BMI, such that the positive association between anxiety sensitivity and BMI was significantly stronger when exercise self-efficacy was low. The same pattern of results emerged for exercise tolerance. Exercise self-efficacy moderated the association between anxiety sensitivity and exercise tolerance, such that the negative association between anxiety sensitivity and exercise tolerance was significantly stronger when exercise self-efficacy was low. Among smokers, anxiety sensitivity may be a risk variable that, directly and indirectly in the context of low self-efficacy for exercise, causes or maintains higher body weight and lower exercise tolerance.

Role of self-reported individual differences in preference for and tolerance of exercise intensity in fitness testing performance.

PubMed

Hall, Eric E; Petruzzello, Steven J; Ekkekakis, Panteleimon; Miller, Paul C; Bixby, Walter R

2014-09-01

Performance in fitness tests could depend on factors beyond the bioenergetic and skeletomuscular systems, such as individual differences in preference for and tolerance of different levels of exercise-induced somatosensory stimulation. Although such individual-difference variables could play a role in exercise testing and prescription, they have been understudied. The purpose of these studies was to examine the relationships of self-reported preference for and tolerance of exercise intensity with performance in fitness tests. Participants in study I were 516 men and women volunteers from a campus community, and participants in study II were 42 men recruit firefighters undergoing a 6-week training program. Both the Preference and Tolerance scores exhibited significant relationships with performance in several fitness tests and with body composition and physical activity participation. Preference and Tolerance did not change after the training program in study II, despite improvements in objective and perceived fitness, supporting their conceptualization as dispositional traits. Preference and Tolerance scores could be useful not only in ameliorating the current understanding of the determinants of physical performance, but also in personalizing exercise prescriptions and, thus, delivering exercise experiences that are more pleasant, tolerable, and sustainable.

Factorial Validity and Invariance Testing of the Exercise Dependence Scale-Revised in Swedish and Portuguese Exercisers

ERIC Educational Resources Information Center

Lindwall, Magnus; Palmeira, Antonio

2009-01-01

The present study investigated the factorial validity and factorial invariance of the 21-item Exercise Dependence Scale-Revised using 162 Swedish and 269 Portuguese exercisers. In addition, the prevalence of exercise dependence symptoms and links to exercise behavior, gender, and age in the two samples was also studied. Confirmatory factor…

Changes in lipid profile variables in response to submaximal and maximal exercise in trained cyclists.

PubMed

El-Sayed, M S; Rattu, A J

1996-01-01

This study examined the effect of prolonged submaximal exercise followed by a self-paced maximal performance test on cholesterol (T-Chol), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC). Nine trained male athletes cycled at 70 percent of maximal oxygen consumption for 60 min, followed by a self-paced maximal ride for 10 min. Venous blood samples were obtained at rest, at 30 and 60 min during submaximal exercise, and immediately after the performance test. Lactic acid, haematocrit (Hct), haemoglobin (Hb), T-Chol and TG were measured in the blood, while plasma was assayed for HDL-C. Plasma volume changes in response to exercise were calculated from Hct and Hb values and all lipid measurements were corrected accordingly. In order to ascertain the repeatability of lipid responses to exercise, all subjects were re-tested under identical testing conditions and experimental protocols. When data obtained during the two exercise trials were analysed by two-way ANOVA no significant differences (P > 0.05) between tests were observed. Consequently the data obtained during the two testing trials were pooled and analysed by one-way ANOVA. Blood lactic acid increased nonsignificantly (P > 0.05) during the prolonged submaximal test, but rose markedly (P <0.05) following the performance ride. Lipid variables ascertained at rest were within the normal range for healthy subjects. ANOVA showed that blood T-Chol and TG were unchanged (P > 0.05), whereas HDL-C rose significantly (P <0.05) in response to exercise. Post hoc analyses indicated that the latter change was due to a significant rise in HDL-C after the performance ride. It is concluded that apparent favourable changes in lipid profile variables occur in response to prolonged submaximal exercise followed by maximal effort, and these changes showed a good level of agreement over the two testing occasions.

NASA's Functional Task Test: High Intensity Exercise Improves the Heart Rate Response to a Stand Test Following 70 Days of Bedrest

NASA Technical Reports Server (NTRS)

Laurie, Steven S.; Lee, Stuart M. C.; Phillips, Tiffany R.; Dillon, E. Lichar; Sheffield-Moore, Melinda; Urban, Randall J.; Ploutz-Snyder, Lori; Stenger, Michael B.; Bloomberg, Jacob J.

2015-01-01

Cardiovascular adaptations due to spaceflight are modeled with 6deg head-down tilt bed rest (BR) and result in decreased orthostatic tolerance. We investigated if high-intensity resistive and aerobic exercise with and without testosterone supplementation would improve the heart rate (HR) response to a 3.5-min stand test and how quickly these changes recovered following BR. During 70 days of BR male subjects performed no exercise (Control, n=10), high intensity supine resistive and aerobic exercise (Exercise, n=9), or supine exercise plus supplemental testosterone (Exercise+T, n=8; 100 mg i.m., weekly in 2-week on/off cycles). We measured HR for 2 min while subjects were prone and for 3 min after standing twice before and 0, 1, 6, and 11 days after BR. Mixed-effects linear regression models were used to evaluate group, time, and interaction effects. Compared to pre-bed rest, prone HR was elevated on BR+0 and BR+1 in Control, but not Exercise or Exercise+T groups, and standing HR was greater in all 3 groups. The increase in prone and standing HR in Control subjects was greater than either Exercise or Exercise+T groups and all groups recovered by BR+6. The change in HR from prone to standing more than doubled on BR+0 in all groups, but was significantly less in the Exericse+T group compared to the Control, but not Exercise group. Exercise reduces, but does not prevent the increase in HR observed in response to standing. The significantly lower HR response in the Exercise+T group requires further investigation to determine physiologic significance.

The protective effects of acute cardiovascular exercise on the interference of procedural memory.

PubMed

Jo, J S; Chen, J; Riechman, S; Roig, M; Wright, D L

2018-04-10

Numerous studies have reported a positive impact of acute exercise for procedural skill memory. Previous work has revealed this effect, but these findings are confounded by a potential contribution of a night of sleep to the reported exercise-mediated reduction in interference. Thus, it remains unclear if exposure to a brief bout of exercise can provide protection to a newly acquired motor memory. The primary objective of the present study was to examine if a single bout of moderate-intensity cardiovascular exercise after practice of a novel motor sequence reduces the susceptibility to retroactive interference. To address this shortcoming, 17 individuals in a control condition practiced a novel motor sequence that was followed by test after a 6-h wake-filled interval. A separate group of 17 individuals experienced practice with an interfering motor sequence 45 min after practice with the original sequence and were then administered test trials 6 h later. One additional group of 12 participants was exposed to an acute bout of exercise immediately after practice with the original motor sequence but prior to practice with the interfering motor sequence and the subsequent test. In comparison with the control condition, increased response times were revealed during the 6-h test for the individuals that were exposed to interference. The introduction of an acute bout of exercise between the practice of the two motor sequences produced a reduction in interference from practice with the second task at the time of test, however, this effect was not statistically significant. These data reinforce the hypothesis that while there may be a contribution from exercise to post-practice consolidation of procedural skills which is independent of sleep, sleep may interact with exercise to strengthen the effects of the latter on procedural memory.

Exercise preconditioning improves behavioral functions following transient cerebral ischemia induced by 4-vessel occlusion (4-VO) in rats.

PubMed

Tahamtan, Mahshid; Allahtavakoli, Mohammad; Abbasnejad, Mehdi; Roohbakhsh, Ali; Taghipour, Zahra; Taghavi, Mohsen; Khodadadi, Hassan; Shamsizadeh, Ali

2013-12-01

There is evidence that exercise decreases ischemia/reperfusion injury in rats. Since behavioral deficits are the main outcome in patients after stroke, our study was designed to investigate whether exercise preconditioning improves the acute behavioral functions and also brain inflammatory injury following cerebral ischemia. Male rats weighing 250-300 g were randomly allocated into five experimental groups. Exercise was performed on a treadmill 30min/day for 3 weeks. Ischemia was induced by 4-vessel occlusion method. Recognition memory was assessed by novel object recognition task (NORT) and step-through passive avoidance task. Sensorimotor function and motor movements were evaluated by adhesive removal test and ledged beam-walking test, respectively. Brain inflammatory injury was evaluated by histological assessment. In NORT, the discrimination ratio was decreased after ischemia (P < 0.05) and exercise preconditioning improved it in ischemic animals. In the passive avoidance test, a significant reduction in response latency was observed in the ischemic group. Exercise preconditioning significantly decreased the response latency in the ischemic rats (P < 0.001). In the adhesive removal test, latency to touch and remove the sticky labels from forepaw was increased following induction of ischemia (all P < 0.001) and exercise preconditioning decreased these indices compared to the ischemic group (all P < 0.001). In the ledged beam-walking test, the slip ratio was increased following ischemia (P < 0.05).  In the ischemia group, marked neuronal injury in hippocampus was observed. These neuropathological changes were attenuated by exercise preconditioning (P < 0.001). Our results showed that exercise preconditioning improves behavioral functions and maintains more viable cells in the dorsal hippocampus of the ischemic brain.

A Pilot Test of the Additive Benefits of Physical Exercise to CBT for OCD.

PubMed

Rector, Neil A; Richter, Margaret A; Lerman, Bethany; Regev, Rotem

2015-01-01

The majority of "responders" to first-line cognitive-behavioural therapy (CBT) and pharmacological treatments for obsessive-compulsive disorder (OCD) are left with residual symptoms that are clinically relevant and disabling. Therefore, there is pressing need for widely accessible efficacious alternative and/or adjunctive treatments for OCD. Accumulating evidence suggests that physical exercise may be one such intervention in the mood and anxiety disorders broadly, although we are aware of only two positive small-scale pilot studies that have tested its clinical benefits in OCD. This pilot study aimed to test the feasibility and preliminary efficacy of adding a structured physical exercise programme to CBT for OCD. A standard CBT group was delivered concurrently with a 12-week customized exercise programme to 11 participants. The exercise regimen was individualized for each participant based on peak heart rate measured using an incremental maximal exercise test. Reports of exercise adherence across the 12-week regimen exceeded 80%. A paired-samples t-test indicated very large treatment effects in Yale-Brown Obsessive-Compulsive Scale scores from pre- to post-treatment in CBT group cohorts led by expert CBT OCD specialists (d = 2.55) and junior CBT clinician non-OCD specialists (d = 2.12). These treatment effects are very large and exceed effects typically observed with individual and group-based CBT for OCD based on leading meta-analytic reviews, as well as previously obtained treatment effects for CBT using the same recruitment protocol without exercise. As such, this pilot work demonstrates the feasibility and significant potential clinical utility of a 12-week aerobic exercise programme delivered in conjunction with CBT for OCD.

CO2-rich phonolitic melt and carbonatite immiscibility in melt inclusions in nephelinite (Hanang volcano, North Tanzanian Divergence, East African Rift).

NASA Astrophysics Data System (ADS)

Baudouin, C.; Parat, F.

2016-12-01

Hanang is the southern volcano of the East branch of the East African Rift and represents volcanic activity at early stage rifting (0.9 Ma). Lavas are highly alkaline Mg-poor nephelinites (Mg#=24.4-35.2) with cpx, garnet, nepheline, titanite, and apatite and result from fractional crystallisation of primary melilitite magmas (Parat et al. AGU2016). In this study, we investigate glassy melt inclusions at the rim of nepheline phenocrysts to constrain the late stage of nephelinite evolution and the behaviour of volatiles (CO2, H2O, S, F, Cl) during magma storage and ascent. The melt inclusions have a green silicate glass, a microcrystalline carbonate phase and a shrinkage bubble free of gas phase (Raman analyses) suggesting that carbonatite-silicate liquid immiscibility (85:15) occurred during nephelinite differentiation. The silicate glasses have trachytic composition (Na+K/Al=1.6-7.2, SiO2=54-65.5 wt%) with high CO2 (0.43 wt% CO2, SIMS analyses), sulfur (0.21-0.92 wt% S) and halogens (0.28-0.84 wt% Cl; 0.35-2.54 wt% F) content and very low H2O content (<0.1wt%, Raman analyses). The carbonate phase is an anhydrous Ca-Na±S,K- carbonate with 33 wt% CaO, 20 wt% Na2O, 3 wt% K2O, and 3 wt% S. The pre-immiscible silicate liquid (e.g. silicate melt + carbonatite) in equilibrium with nepheline and cpx phenocrysts has CO2-rich phonolitic composition (Na+K/Al=6.2-6.9) with 6 ± 1.5 wt% CO2 at pressure of 700-1100 MPa. The entrapped melt in nepheline corresponds to evolved interstitial silicate melt after crystallisation of cpx (16.7%), nepheline (40%) garnet (6.5%) and apatite (1.7%) from Mg-nephelinite magma. The immiscibility process leading to glassy silicate melt and microcrystalline carbonatitic melt occurred in closed system during rapid ascent at crustal level at 200-230 MPa. The absence of gas phase in shrinkage bubble in melt inclusions suggests CO2-undersaturated conditions during quenching. The absence of carbonatite lavas at Hanang volcano is then explained by open system differentiation with primary melilititic magma replenishment preventing alkaline enrichment and carbonatite-silicate liquid immiscibility at depth as observed for the nephelinite-natrocarbonatite Oldoinyo Lengai volcano in the Natron Basin (150 km north).

Petrology and fluid inclusions of garnet-clinopyroxene rocks from the Gondwana suture zone in southern India: Implications for prograde high-pressure metamorphism

NASA Astrophysics Data System (ADS)

Tsunogae, T.

2012-04-01

The Palghat-Cauvery Suture Zone (PCSZ) in the southern granulite terrane, India, which separates Pan-African granulite blocks (e.g., Madurai and Trivandrum Blocks) to the south and Archean terrane (e.g., Salem Block and Dharwar Craton) to the north is regarded as a major suture zone in the Gondwana collisional orogeny. It probably continues westwards to the Betsimisaraka suture in Madagascar, and eastwards into Sri Lanka and possibly into Antarctica. The available geochronological data including U-Pb zircon and EPMA monazite ages indicate that the rocks along the PCSZ underwent an episode of high-grade metamorphism at ca. 530 Ma that broadly coincides with the time of final assembly of the Gondwana supercontinent. Recent investigations on high-grade metamorphic rocks in this region have identified several new occurrences of garnet-clinopyroxene rocks and associated meta-gabbros from Perundurai, Paramati, Aniyapuram, Vadugappatti, and Mahadevi areas in Namakkal region within the central domain of the PCSZ. They occur as elongated boudins of 1 m to 1 km in length within hornblende-biotite orthogneiss. The garnet-clinopyroxene mafic granulites contain coarse-grained (up to several cm) garnet (Alm30-50 Pyr30-40 Grs10-20) and clinopyroxene (XMg = 0.70-0.85) with minor pargasite, plagioclase (An30-40), orthopyroxene (hypersthene), and rutile. Garnet and clinopyroxene are both subidioblastic and contain few inclusions of clinopyroxene (in garnet) and plagioclase. Orthopyroxene occur only as Opx + Pl symplectite between garnet and clinopyroxene in almost all the localities, suggesting the progress of decompressional reaction: Grt + Cpx + Qtz => Opx + Pl, which is a dominant texture in the PCSZ. The prograde mineral assemblage of the rocks is therefore inferred to be Grt + Cpx + Qtz, although quartz was probably totally consumed by the progress of the reaction. The metamorphic P-T calculations using Grt-Cpx-Pl-Qtz geothermobarometers yield T = 850-900°C and P >13 kbar, which is consistent with the occurrence of high-pressure Mg-rich staurolite in Mg-Al-rich rocks from this region. Fluid inclusion study of some garnet-clinopyroxene rock samples identified CO2-rich fluid inclusions trapped as primary phases within garnet, suggesting that prograde high-pressure metamorphism was dominated by CO2-rich fluids. The results therefore confirmed that the PCSZ underwent regional dry high-pressure metamorphism followed by the peak ultrahigh-temperature event probably associated with the continent-continent collisional and suturing history along the PCSZ.

K-rich glass-bearing wehrlite xenoliths from Yitong, Northeastern China: petrological and chemical evidence for mantle metasomatism

NASA Astrophysics Data System (ADS)

Xu, Y.; Mercier, J.-C. C.; Lin, Chuanyong; Shi, Lanbin; Menzies, M. A.; Ross, J. V.; Harte, B.

1996-11-01

Ultramafic xenoliths in Cenozoic alkali basalts from Yitong, northeast China comprise three types in terms of their modal mineralogy: lherzolite, pyroxenite and wehrlite. The wehrlite suite always contains interstitial pale/brown glass which occupies several per cent by volume of the whole rock. The texture of the wehrlites is porphyroclastic with some large strained grains of olivine (0.5 1 mm) scattered in a very fine grained matrix (0.1 mm), implying a metamorphic origin for the protolith rather than an igneous origin. The host minerals are compositionally zoned, showing evidence of reaction with a melt. Petrological evidence for resorption of spinel (lherzolite) and orthopyroxene (wehrlite) by infiltrating melt further supports the hypothesis that the wehrlites result from interaction between a partial melting residue and a melt, which preferentially replaced primary spinel, Cr-diopside and enstatite to produce secondary clinopyroxene (cpx) + olivine (ol) ± chromite ± feldspar (fd). The composition of the mineral phases supports this inference and, further indicates that, prior to melt impregnation, the protoliths of these wehrlites must have been subjected to at least one earlier Fe-enrichment event. This explanation is consistent with the restricted occurrence of glasses in the wehrlite suite. The glass is generally associated with fine-grained (0.1 mm) minerals (cpx+ol+chromite ±fd). Electron microprobe analyses of these glasses show them to have high SiO2 content (54 60 wt%), a high content of alkalis (Na2O, 5.6 8.0%; K2O, 6.3 9.0%), high Al2O3 (20 24%), and a depletion in CaO (0.13 2.83%), FeO (0.89 4.42%) and MgO (0.29 1.18%). Ion probe analyses reveal a light rare earth element-enrichment in these glasses with chondrite normalised (La)n = 268 480. The high K2O contents in these glasses and their mode of occurrence argue against an origin by in-situ melting of pre-existent phases. Petrographic characteristics and trace element data also exclude the possibility of percolation of host-basalt related melts for the origin of these glasses. Thus the glasses must have resulted from local penetration of mantle metasomatic melts which may have been produced by partial melting of peridotites with involvement of deep-seated fluids. Such melts may have been significantly modified by subsequent fractional crystallization of ol, cpx and sp, extensive reaction with the mantle conduit and the xenolith transport process.

Profile of the HIV Epidemic in Cape Verde: Molecular Epidemiology and Drug Resistance Mutations among HIV-1 and HIV-2 Infected Patients from Distinct Islands of the Archipelago

PubMed Central

de Pina-Araujo, Isabel Inês M.; Guimarães, Monick L.; Bello, Gonzalo; Vicente, Ana Carolina P.; Morgado, Mariza G.

2014-01-01

HIV-1 and HIV-2 have been detected in Cape Verde since 1987, but little is known regarding the genetic diversity of these viruses in this archipelago, located near the West African coast. In this study, we characterized the molecular epidemiology of HIV-1 and HIV-2 and described the occurrence of drug resistance mutations (DRM) among antiretroviral therapy naïve (ARTn) patients and patients under treatment (ARTexp) from different Cape Verde islands. Blood samples, socio-demographic and clinical-laboratory data were obtained from 221 HIV-positive individuals during 2010–2011. Phylogenetic and bootscan analyses of the pol region (1300 bp) were performed for viral subtyping. HIV-1 and HIV-2 DRM were evaluated for ARTn and ARTexp patients using the Stanford HIV Database and HIV-GRADE e.V. Algorithm Homepage, respectively. Among the 221 patients (169 [76.5%] HIV-1, 43 [19.5%] HIV-2 and 9 [4.1%] HIV-1/HIV-2 co-infections), 67% were female. The median ages were 34 (IQR = 1–75) and 47 (IQR = 12–84) for HIV-1 and HIV-2, respectively. HIV-1 infections were due to subtypes G (36.6%), CRF02_AG (30.6%), F1 (9.7%), URFs (10.4%), B (5.2%), CRF05_DF (3.0%), C (2.2%), CRF06_cpx (0.7%), CRF25_cpx (0.7%) and CRF49_cpx (0.7%), whereas all HIV-2 infections belonged to group A. Transmitted DRM (TDRM) was observed in 3.4% (2/58) of ARTn HIV-1-infected patients (1.7% NRTI, 1.7% NNRTI), but not among those with HIV-2. Among ARTexp patients, DRM was observed in 47.8% (33/69) of HIV-1 (37.7% NRTI, 37.7% NNRTI, 7.4% PI, 33.3% for two classes) and 17.6% (3/17) of HIV-2-infections (17.6% NRTI, 11.8% PI, 11.8% both). This study indicates that Cape Verde has a complex and unique HIV-1 molecular epidemiological scenario dominated by HIV-1 subtypes G, CRF02_AG and F1 and HIV-2 subtype A. The occurrence of TDRM and the relatively high level of DRM among treated patients are of concern. Continuous monitoring of patients on ART, including genotyping, are public policies to be implemented. PMID:24763617

High intensity intermittent games-based activity and adolescents' cognition: moderating effect of physical fitness.

PubMed

Cooper, Simon B; Dring, Karah J; Morris, John G; Sunderland, Caroline; Bandelow, Stephan; Nevill, Mary E

2018-05-08

An acute bout of exercise elicits a beneficial effect on subsequent cognitive function in adolescents. The effect of games-based activity, an ecologically valid and attractive exercise model for young people, remains unknown; as does the moderating effect of fitness on the acute exercise-cognition relationship. Therefore, the aim of the present study was to examine the effect of games-based activity on subsequent cognition in adolescents, and the moderating effect of fitness on this relationship. Following ethical approval, 39 adolescents (12.3 ± 0.7 year) completed an exercise and resting trial in a counterbalanced, randomised crossover design. During familiarisation, participants completed a multi-stage fitness test to predict VO 2 peak. The exercise trial consisted of 60-min games-based activity (basketball), during which heart rate was 158 ± 11 beats∙min - 1 . A battery of cognitive function tests (Stroop test, Sternberg paradigm, trail making and d2 tests) were completed 30-min before, immediately following and 45-min following the basketball. Response times on the complex level of the Stroop test were enhanced both immediately (p = 0.021) and 45-min (p = 0.035) post-exercise, and response times on the five item level of the Sternberg paradigm were enhanced immediately post-exercise (p = 0.023). There were no effects on the time taken to complete the trail making test or any outcome of the d2 test. In particular, response times were enhanced in the fitter adolescents 45-min post-exercise on both levels of the Stroop test (simple, p = 0.005; complex, p = 0.040) and on the three item level of the Sternberg paradigm immediately (p = 0.017) and 45-min (p = 0.008) post-exercise. Games-based activity enhanced executive function and working memory scanning speed in adolescents, an effect particularly evident in fitter adolescents, whilst the high intensity intermittent nature of games-based activity may be too demanding for less fit children.

Hormonal responses in athletes: the use of a two bout exercise protocol to detect subtle differences in (over)training status.

PubMed

Meeusen, R; Piacentini, M F; Busschaert, B; Buyse, L; De Schutter, G; Stray-Gundersen, J

2004-03-01

In overtrained athletes, several signs and symptoms have been associated with the imbalance between training and recovery. However, reliable diagnostic markers for distinguishing between well-trained, overreached (OR) and overtrained (OT) athletes are lacking. A hallmark feature of overtraining syndrome (OTS) is the inability to sustain intense exercise and recover for the next training or competition session. We therefore devised a test protocol utilizing two bouts of maximal work. With this test protocol we tried to establish a difference in hormonal responses between the training status of T and OR athletes. Seven well-trained cyclists participated in this study and were tested before and after a training camp. We also present the data of one OT motocross athlete who was clinically diagnosed as overtrained. All athletes performed two maximal exercise tests separated by 4 h. Blood was analyzed for cortisol, adrenocorticotrophic hormone (ACTH), growth hormone and prolactin (PRL). Performance decreased by 6% between the first and the second exercise test in the OR group and by 11% in the OT subject. Moreover, during the second exercise test there were more marked differences between the T and OR athletes; in particular, the OT subject did not show an increase in some of the hormonal responses. PRL increased only by 14% in the OT subject's second test and there was a 7% decrease in ACTH. The two exercise approach enables us to detect subtle performance decrements that will not be identified by one exercise trigger. The hormonal responses to the second exercise test were different between the T and OR athletes (the increase in the T group was higher than in the OR that was higher than in the OT). The results of the case presentation of an overtrained athlete provide evidence of an altered and dysfunctional hypothalamic-pituitary axis response to two bouts of maximal exercise. These findings can be used to develop markers for diagnosis of OTS and to begin to address the pathologic mechanism operative in the syndrome, as well as providing an outcome measure to evaluate possible therapeutic regimes.

Sinusoidal high-intensity exercise does not elicit ventilatory limitation in chronic obstructive pulmonary disease.

PubMed

Porszasz, Janos; Rambod, Mehdi; van der Vaart, Hester; Rossiter, Harry B; Ma, Shuyi; Kiledjian, Rafi; Casaburi, Richard

2013-06-01

During exercise at critical power (CP) in chronic obstructive pulmonary disease (COPD) patients, ventilation approaches its maximum. As a result of the slow ventilatory dynamics in COPD, ventilatory limitation during supramaximal exercise might be escaped using rapid sinusoidal forcing. Nine COPD patients [age, 60.2 ± 6.9 years; forced expiratory volume in the first second (FEV(1)), 42 ± 17% of predicted; and FEV(1)/FVC, 39 ± 12%] underwent an incremental cycle ergometer test and then four constant work rate cycle ergometer tests; tolerable duration (t(lim)) was recorded. Critical power was determined from constant work rate testing by linear regression of work rate versus 1/t(lim). Patients then completed fast (FS; 60 s period) and slow (SS; 360 s period) sinusoidally fluctuating exercise tests with mean work rate at CP and peak at 120% of peak incremental test work rate, and one additional test at CP; each for a 20 min target. The value of t(lim) did not differ between CP (19.8 ± 0.6 min) and FS (19.0 ± 2.5 min), but was shorter in SS (13.2 ± 4.2 min; P < 0.05). The sinusoidal ventilatory amplitude was minimal (37.4 ± 34.9 ml min(-1) W(-1)) during FS but much larger during SS (189.6 ± 120.4 ml min(-1) W(-1)). The total ventilatory response in SS reached 110 ± 8.0% of the incremental test peak, suggesting ventilatory limitation. Slow components in ventilation during constant work rate and FS exercises were detected in most subjects and contributed appreciably to the total response asymptote. The SS exercise was associated with higher mid-exercise lactate concentrations (5.2 ± 1.7, 7.6 ± 1.7 and 4.5 ± 1.3 mmol l(-1) in FS, SS and CP). Large-amplitude, rapid sinusoidal fluctuation in work rate yields little fluctuation in ventilation despite reaching 120% of the incremental test peak work rate. This high-intensity exercise strategy might be suitable for programmes of rehabilitative exercise training in COPD.

Impact of CPAP on physical exercise tolerance and sympathetic-vagal balance in patients with chronic heart failure.

PubMed

Reis, Hugo V; Borghi-Silva, Audrey; Catai, Aparecida M; Reis, Michel S

2014-01-01

Chronic heart failure (CHF) leads to exercise intolerance. However, non-invasive ventilation is able to improve functional capacity of patients with CHF. The aim of this study was to evaluate the effectiveness of continuous positive airway pressure (CPAP) on physical exercise tolerance and heart rate variability (HRV) in patients with CHF. Method : Seven men with CHF (62 ± 8 years) and left ventricle ejection fraction of 41 ± 8% were submitted to an incremental symptom-limited exercise test (IT) on the cicloergometer. On separate days, patients were randomized to perform four constant work rate exercise tests to maximal tolerance with and without CPAP (5 cmH2O) in the following conditions: i) at 50% of peak work rate of IT; and ii) at 75% of peak work rate of IT. At rest and during these conditions, instantaneous heart rate (HR) was recorded using a cardiofrequencimeter and HRV was analyzed in time domain (SDNN and RMSSD indexes). For statistical procedures, Wilcoxon test or Kruskall-Wallis test with Dunn's post-hoc were used accordingly. In addition, categorical variables were analysed through Fischer's test (p<0.05). There were significant improvements in exercise tolerance at 75% of peak work rate of IT with CPAP (405 ± 52 vs. 438 ± 58 s). RMSSD indexes were lower during exercise tests compared to CPAP at rest and with 50% of peak work rate of IT. These data suggest that CPAP appears to be a useful strategy to improve functional capacity in patients with CHF. However, the positive impact of CPAP did not generate significant changes in the HRV during physical exercises.

Walking Aids Moderate Exercise Effects on Gait Speed in People With Dementia: A Randomized Controlled Trial.

PubMed

Toots, Annika; Littbrand, Håkan; Holmberg, Henrik; Nordström, Peter; Lundin-Olsson, Lillemor; Gustafson, Yngve; Rosendahl, Erik

2017-03-01

To investigate the effects of exercise on gait speed, when tested using walking aids and without, and whether effects differed according to amount of support in the test. A cluster-randomized controlled trial. The Umeå Dementia and Exercise (UMDEX) study was set in 16 nursing homes in Umeå, Sweden. One hundred forty-one women and 45 men (mean age 85 years) with dementia, of whom 145 (78%) habitually used walking aids. Participants were randomized to the high-intensity functional exercise program or a seated attention control activity. Blinded assessors measured 4-m usual gait speed with walking aids if any gait speed (GS), and without walking aids and with minimum amount of support, at baseline, 4 months (on intervention completion), and 7 months. Linear mixed models showed no between-group effect in either gait speed test at 4 or 7 months. In interaction analyses exercise effects differed significantly between participants who walked unsupported compared with when walking aids or minimum support was used. Positive between-group exercise effects on gait speed (m/s) were found in subgroups that walked unsupported at 4 and 7 months (GS: 0.07, P = .009 and 0.13, P < .001; and GS test without walking aids: 0.05, P = .011 and 0.07, P = .029, respectively). In people with dementia living in nursing homes exercise had positive effects on gait when tested unsupported compared with when walking aids or minimum support was used. The study suggests that the use of walking aids in gait speed tests may conceal exercise effects. Copyright © 2016 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Effects of home-based pulmonary rehabilitation with a metronome-guided walking pace in chronic obstructive pulmonary disease.

PubMed

Lee, Sung-soon; Kim, Changhwan; Jin, Young-Soo; Oh, Yeon-Mok; Lee, Sang-Do; Yang, Yun Jun; Park, Yong Bum

2013-05-01

Despite documented efficacy and recommendations, pulmonary rehabilitation (PR) in chronic obstructive pulmonary disease (COPD) has been underutilized. Home-based PR was proposed as an alternative, but there were limited data. The adequate exercise intensity was also a crucial issue. The aim of this study was to investigate the effects of home-based PR with a metronome-guided walking pace on functional exercise capacity and health-related quality of life (HRQOL) in COPD. The subjects participated in a 12-week home-based PR program. Exercise intensity was initially determined by cardiopulmonary exercise test, and was readjusted (the interval of metronome beeps was reset) according to submaximal endurance test. Six-minute walk test, pulmonary function test, cardiopulmonary exercise test, and St. George's Respiratory Questionnaire (SGRQ) were done before and after the 12-week program, and at 6 months after completion of rehabilitation. Thirty-three patients participated in the program. Six-minute walking distance was significantly increased (48.8 m; P = 0.017) and the SGRQ score was also improved (-15; P < 0.001) over the six-month follow-up period after rehabilitation. There were no significant differences in pulmonary function and peak exercise parameters. We developed an effective home-based PR program with a metronome-guided walking pace for COPD patients. This rehabilitation program may improve functional exercise capacity and HRQOL.

Flow for Exercise Adherence: Testing an Intrinsic Model of Health Behavior

ERIC Educational Resources Information Center

Petosa, R. Lingyak; Holtz, Brian

2013-01-01

Background: Health behavior theory generally does not include intrinsic motivation as a determinate of health practices. Purpose: The purpose of this study was to test the flow theory of exercise adherence. Flow theory posits that exercise can be intrinsically rewarding if the experiences of self/time transcendence and control/mastery are achieved…

33 CFR 103.515 - Exercises.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Exercises. 103.515 Section 103... MARITIME SECURITY: AREA MARITIME SECURITY Area Maritime Security (AMS) Plan § 103.515 Exercises. (a) The... exercise at least once each calendar year, with no more than 18 months between exercises, to test the...

33 CFR 103.515 - Exercises.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Exercises. 103.515 Section 103... MARITIME SECURITY: AREA MARITIME SECURITY Area Maritime Security (AMS) Plan § 103.515 Exercises. (a) The... exercise at least once each calendar year, with no more than 18 months between exercises, to test the...

33 CFR 103.515 - Exercises.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Exercises. 103.515 Section 103... MARITIME SECURITY: AREA MARITIME SECURITY Area Maritime Security (AMS) Plan § 103.515 Exercises. (a) The... exercise at least once each calendar year, with no more than 18 months between exercises, to test the...

33 CFR 103.515 - Exercises.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Exercises. 103.515 Section 103... MARITIME SECURITY: AREA MARITIME SECURITY Area Maritime Security (AMS) Plan § 103.515 Exercises. (a) The... exercise at least once each calendar year, with no more than 18 months between exercises, to test the...

Design and pilot evaluation of competitive and cooperative exercise games for arm rehabilitation at home.

PubMed

Gorsic, Maja; Novak, Domen

2016-08-01

People with chronic arm impairment should exercise intensely at home after completing their clinical rehabilitation program, but frequently lack motivation. To address this issue, we present a home rehabilitation system that motivates patients by allowing them to perform arm exercises together with friends or relatives in competitive and cooperative games. Inertial sensors are used to track the patient's arm and control the game. The system was tested with seven adults with arm impairment as well as their friends or spouses. They tested four exercise games (single-player, competitive and two different cooperative games) for 3 minutes each. Of the 7 participants, 4 preferred the competitive game, 2 preferred a cooperative game, and 1 preferred to exercise alone. Competition also increased exercise intensity (measured using inertial sensors) compared to exercising alone. Though preliminary, these results indicate that competitive exercise games could improve arm rehabilitation at home for survivors of neurological and orthopedic injuries.

Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise

PubMed Central

Jankord, Ryan; McAllister, Richard M.; Ganjam, Venkataseshu K.; Laughlin, M. Harold

2009-01-01

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise. Female Yucatan miniature swine were treated with N-nitro-l-arginine methyl ester (l-NAME) to test the effect of chronic nitric oxide synthase (NOS) inhibition on the ACTH response to exercise. In addition, we tested the effect of NOS inhibition on blood flow to tissues of the HPA axis and report the effects of handling and treadmill exercise on the plasma concentrations of ACTH and cortisol. Chronic NOS inhibition decreased plasma NOx levels by 44%, increased mean arterial blood pressure by 46%, and increased expression of neuronal NOS in carotid arteries. Vascular conductance was decreased in the frontal cortex, the hypothalamus, and the adrenal gland. Chronic NOS inhibition exaggerated the ACTH response to exercise. In contrast, chronic NOS inhibition decreased the ACTH response to restraint, suggesting that the role of NO in modulating HPA activity is stressor dependent. These results demonstrate that NOS activity modulates the response of the neuroendocrine component of the HPA axis during exercise stress. PMID:19144752

Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise.

PubMed

Jankord, Ryan; McAllister, Richard M; Ganjam, Venkataseshu K; Laughlin, M Harold

2009-03-01

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise. Female Yucatan miniature swine were treated with N-nitro-l-arginine methyl ester (l-NAME) to test the effect of chronic nitric oxide synthase (NOS) inhibition on the ACTH response to exercise. In addition, we tested the effect of NOS inhibition on blood flow to tissues of the HPA axis and report the effects of handling and treadmill exercise on the plasma concentrations of ACTH and cortisol. Chronic NOS inhibition decreased plasma NO(x) levels by 44%, increased mean arterial blood pressure by 46%, and increased expression of neuronal NOS in carotid arteries. Vascular conductance was decreased in the frontal cortex, the hypothalamus, and the adrenal gland. Chronic NOS inhibition exaggerated the ACTH response to exercise. In contrast, chronic NOS inhibition decreased the ACTH response to restraint, suggesting that the role of NO in modulating HPA activity is stressor dependent. These results demonstrate that NOS activity modulates the response of the neuroendocrine component of the HPA axis during exercise stress.

Dose-Response Effects of Exercise Duration and Recovery on Cognitive Functioning.

PubMed

Crush, Elizabeth A; Loprinzi, Paul D

2017-12-01

We examined the effects of different acute exercise durations and recovery periods on cognitive function in a counterbalanced, cross-over randomized controlled experiment. We placed 352 participants, aged 18 to 35 years into one of 16 experimental groups. Each participant visited the laboratory twice, separated by a 1-week washout period. Either Visit 1 or 2 consisted of an acute bout of moderate-intensity treadmill exercise (10, 20, 30, 45, or 60 minutes) followed by a period of rest (5, 15, or 30 minutes) before taking a set of five cognitive tests; the other visit consisted only of completing the cognitive tests (no exercise). Cognitive tests sampled multiple cognitive parameters, including reasoning, concentration, memory, attention, and planning. We found that a short recovery period (i.e., 5 minutes) may have a less favorable effect on planning ability but may be beneficial for memory. In addition, for various exercise durations and recovery periods, a Group × Time × Resting (nonexercise) A cognitive interaction effect was observed such that for both memory and inhibitory cognitive ability, acute exercise (vs. no exercise) had an enhancement effect for those with lower resting cognitive functioning. The length of the acute exercise recovery period and resting cognitive ability most influenced the association between exercise and cognitive function.

Evaluation of Cooper 12-minute walk/run test as a marker of cardiorespiratory fitness in young urban children with persistent asthma.

PubMed

Weisgerber, Michael; Danduran, Michael; Meurer, John; Hartmann, Kathryn; Berger, Stuart; Flores, Glenn

2009-07-01

To evaluate Cooper 12-minute run/walk test (CT12) as a one-time estimate of cardiorespiratory fitness and marker of fitness change compared with treadmill fitness testing in young children with persistent asthma. A cohort of urban children with asthma participated in the asthma and exercise program and a subset completed pre- and postintervention fitness testing. Treadmill fitness testing was conducted by an exercise physiologist in the fitness laboratory at an academic children's hospital. CT12 was conducted in a college recreation center gymnasium. Forty-five urban children with persistent asthma aged 7 to 14 years participated in exercise interventions. A subset of 19 children completed pre- and postintervention exercise testing. Participants completed a 9-week exercise program where they participated in either swimming or golf 3 days a week for 1 hour. A subset of participants completed fitness testing by 2 methods before and after program completion. CT12 results (meters), maximal oxygen consumption ((.)Vo2max) (mL x kg(-1) x min(-1)), and treadmill exercise time (minutes). CT12 and maximal oxygen consumption were moderately correlated (preintervention: 0.55, P = 0.003; postintervention: 0.48, P = 0.04) as one-time measures of fitness. Correlations of the tests as markers of change over time were poor and nonsignificant. In children with asthma, CT12 is a reasonable one-time estimate of fitness but a poor marker of fitness change over time.

Non-Potassic Melts In CMAS-CO2-H2O-K2O Model Peridotite

NASA Astrophysics Data System (ADS)

Buisman, I.; Walter, M. J.; Keshav, S.

2009-12-01

Volatile mediated model systems have been fundamental in shaping our knowledge about the way we view melting phase relations of peridotite at various depths in the Earth. Volatiles not only affect the melting temperatures, but the resulting liquids are, in some case, dramatically different than those witnessed in melting of dry peridotite. For example, the influence of CO2 and H2O on the melting phase relations of model peridotite shows a remarkable decrease in the solidus temperatures when compared to the dry peridotite (Gudfinnsson and Presnall, 2005). These model systems illustrate a gradational change above the solidus from carbonatites to kimberlites over several hundreds of degrees. Group-II kimberlites are ultrapotassic rocks with high water content where the mineral phlogopite is abundant. To get a better understanding of the melting phase relations related to carbonatitic and kimberlitic magmas, K2O was added to the system CMAS-CO2-H2O. In these systems, fluid and melt can co-exist in P-T space. However, from past studies, it is also known that in hydrous systems, both the fluid and melt will become indistinguishable from one another creating a singularity (second critical endpoint). Starting from the solidus located in six components (Keshav and Gudfinnsson, AGU abstract, 2009), with seven phases, melting phase relations in CMAS-CO2-H2O-K2O involving, fo-opx-cpx-garnet-carbonate-melt-fluid, are divariant. Fluid was recognized with the observation of large cavities seen in exposed capsules. Moreover, the presence of bright, needle-like grains found in large cavities in backscattered images implies the presence of solute in the fluid phase. Significantly, liquids on this divariant region have about 1000 ppm K2O, and so is the case with accompanying cpx. Hence, with this non-interesting amount of K2O in the mentioned phases, fluid must have all the potassium. At 30 kbar/1100C, with fo-opx-cpx-garnet-carbonate-phlogopite-melt-fluid, the melting phase relations become isobarically invariant. In contrast, the solidus in CMAS-CO2-H2O at 30 kbar is at 1000C. Above 1100C, phlogopite is no longer in equilibrium with the phase assemblage. In all the experimental charges, capsules were pierced, and a hydrous solution was seen escaping. When tested with litmus paper, in all cases at 25-50 kbar, this solution was determined to be highly basic (pH>10). Upon evaporation of the hydrous solution, a white precipitate was left behind around the piercing on the capsule wall. In CMAS-CO2-H2O, the fluid was found to be almost neutral (pH 7-8). The melt present in our experiments is carbonatitic in nature and does not contain any significant amounts of K2O. This contradicts a recent study on K2O in a natural composition (Foley et al, 2009) where carbonatitic melt had up to 13 wt% of K2O. Significantly, since K2O is perhaps all in the fluid, source regions for potassic magmas in the Earth’s mantle could not be created by metasomatism of alkali-rich, carbonatitic melts.

Impact of polyphenol antioxidants on cycling performance and cardiovascular function.

PubMed

Trinity, Joel D; Pahnke, Matthew D; Trombold, Justin R; Coyle, Edward F

2014-03-24

This investigation sought to determine if supplementation with polyphenol antioxidant (PA) improves exercise performance in the heat (31.5 °C, 55% RH) by altering the cardiovascular and thermoregulatory responses to exercise. Twelve endurance trained athletes ingested PA or placebo (PLAC) for 7 days. Consecutive days of exercise testing were performed at the end of the supplementation periods. Cardiovascular and thermoregulatory measures were made during exercise. Performance, as measured by a 10 min time trial (TT) following 50 min of moderate intensity cycling, was not different between treatments (PLAC: 292 ± 33 W and PA: 279 ± 38 W, p = 0.12). Gross efficiency, blood lactate, maximal neuromuscular power, and ratings of perceived exertion were also not different between treatments. Similarly, performance on the second day of testing, as assessed by time to fatigue at maximal oxygen consumption, was not different between treatments (PLAC; 377 ± 117 s vs. PA; 364 ± 128 s, p = 0.61). Cardiovascular and thermoregulatory responses to exercise were not different between treatments on either day of exercise testing. Polyphenol antioxidant supplementation had no impact on exercise performance and did not alter the cardiovascular or thermoregulatory responses to exercise in the heat.

Heart rate behavior during an exercise stress test in obese patients.

PubMed

Gondoni, L A; Titon, A M; Nibbio, F; Augello, G; Caetani, G; Liuzzi, A

2009-03-01

Heart rate (HR) response to exercise has not been fully described in the obese. We wanted to study the differences between obese and non-obese patients in HR behavior during an exercise stress test and to determine whether these differences influence exercise capacity. We studied 554 patients (318 females) who underwent a treadmill exercise test. All subjects were in sinus rhythm. Patients with ischemic heart disease, with reduced ejection fraction and patients taking drugs that interfere with HR were excluded. The population included 231 patients with BMI<30 kg/m(2) (group 1), 212 patients who were unfit and obese (group 2) and 111 patients who were trained obese (group 3). Resting HR was similar in the various groups. Peak HR, HR recovery and chronotropic index were lower in obese subjects, regardless of their fitness level. Multivariate analysis showed that HR related variables were associated with age, BMI, height, hypertension and various pharmacologic treatments, while exercise capacity was strongly dependent on HR behavior, as well as on sex, age, BMI and diabetes. Obese subjects have a marked impairment of HR behavior during exercise and in the recovery period, and the blunted increase in HR is the most important factor that influences exercise capacity.

Ventilatory abnormalities in patients with cystic fibrosis undergoing the submaximal treadmill exercise test.

PubMed

Parazzi, Paloma Lopes Francisco; Marson, Fernando Augusto de Lima; Ribeiro, Maria Angela Gonçalves de Oliveira; de Almeida, Celize Cruz Bresciani; Martins, Luiz Cláudio; Paschoal, Ilma Aparecida; Toro, Adyleia Aparecida Dalbo Contrera; Schivinski, Camila Isabel Santos; Ribeiro, Jose Dirceu

2015-05-19

Exercise has been studied as a prognostic marker for patients with cystic fibrosis (CF), as well as a tool for improving their quality of life and analyzing lung disease. In this context, the aim of the present study was to evaluate and compare variables of lung functioning. Our data included: (i) volumetric capnography (VCAP) parameters: expiratory minute volume (VE), volume of exhaled carbon dioxide (VCO2), VE/VCO2, ratio of dead space to tidal volume (VD/VT), and end-tidal carbon dioxide (PetCO2); (ii) spirometry parameters: forced vital capacity (FVC), percent forced expiratory volume in the first second of the FVC (FEV1%), and FEV1/FVC%; and (iii) cardiorespiratory parameters: heart rate (HR), respiratory rate, oxygen saturation (SpO2), and Borg scale rating at rest and during exercise. The subjects comprised children, adolescents, and young adults aged 6-25 years with CF (CF group [CFG]) and without CF (control group [CG]). This was a clinical, prospective, controlled study involving 128 male and female patients (64 with CF) of a university hospital. All patients underwent treadmill exercise tests and provided informed consent after study approval by the institutional ethics committee. Linear regression, Kruskal-Wallis test, and Mann-Whitney test were performed to compare the CFG and CG. The α value was set at 0.05. Patients in the CFG showed significantly different VCAP values and spirometry variables throughout the exercise test. Before, during, and after exercise, several variables were different between the two groups; statistically significant differences were seen in the spirometry parameters, SpO2, HR, VCO2, VE/VCO2, PetCO2, and Borg scale rating. VCAP variables changed at each time point analyzed during the exercise test in both groups. VCAP can be used to analyze ventilatory parameters during exercise. All cardiorespiratory, spirometry, and VCAP variables differed between patients in the CFG and CG before, during, and after exercise.

Just Keep Swimming: Neuroendocrine, Metabolic, and Behavioral Changes After a Forced Swimming Test in Zebrafish.

PubMed

da Rosa, João Gabriel Santos; Barcellos, Heloísa Helena de Alcântara; Idalencio, Renan; Marqueze, Alessandra; Fagundes, Michele; Rossini, Mainara; Variani, Cristiane; Balbinoti, Francine; Tietböhl, Tássia Michele Huff; Rosemberg, Denis Broock; Barcellos, Leonardo José Gil

2017-02-01

In this study, we show that an adaptation of the spinning test can be used as a model to study the exercise-exhaustion-recovery paradigm in fish. This forced swimming test promotes a wide range of changes in the hypothalamus-pituitary-interrenal axis functioning, intermediary metabolism, as well in fish behavior at both exercise and recovery periods. Our results pointed that this adapted spinning test can be considered a valuable tool for evaluating drugs and contaminant effects on exercised fish. This can be a suitable protocol both to environmental-to evaluate contaminants that act in fish energy mobilization and recovery after stressors-and translational perspectives-effects of drugs on exercised or stressed humans.

Diet and exercise changes following direct-to-consumer personal genomic testing.

PubMed

Nielsen, Daiva Elena; Carere, Deanna Alexis; Wang, Catharine; Roberts, J Scott; Green, Robert C

2017-05-02

The impacts of direct-to-consumer personal genomic testing (PGT) on health behaviors such as diet and exercise are poorly understood. Our investigation aimed to evaluate diet and exercise changes following PGT and to determine if changes were associated with genetic test results obtained from PGT. Customers of 23andMe and Pathway Genomics completed a web-based survey prior to receiving PGT results (baseline) and 6 months post-results. Fruit and vegetable intake (servings/day), and light, vigorous and strength exercise frequency (days/week) were assessed. Changes in diet and exercise were examined using paired t-tests and linear regressions. Additional analyses examined whether outcomes differed by baseline self-reported health (SRH) or content of PGT results. Longitudinal data were available for 1,002 participants. Significant increases were observed for vegetable intake (mean Δ = 0.11 (95% CI = 0.05, 0.17), p = 0.0003) and strength exercise (Δ = 0.14 (0.03, 0.25), p = 0.0153). When stratified by SRH, significant increases were observed for all outcomes among lower SRH participants: fruit intake, Δ = 0.11 (0.02, 0.21), p = 0.0148; vegetable intake, Δ = 0.16 (0.07, 0.25), p = 0.0005; light exercise, Δ = 0.25 (0.03, 0.47), p = 0.0263; vigorous exercise, Δ = 0.23 (0.06, 0.41), p = 0.0097; strength exercise, Δ = 0.19 (0.01, 0.37), p = 0.0369. A significant change among higher SRH participants was only observed for light exercise, and in the opposite direction: Δ = -0.2468 (-0.06, -0.44), p = 0.0111. Genetic results were not consistently associated with any diet or exercise changes. The experience of PGT was associated with modest, mostly positive changes in diet and exercise. Associations were independent of genetic results from PGT.

Measuring the effects of massage on exercise performance and cardiopulmonary response in children with and without heart disease: a pilot study.

PubMed

Beider, Shay; Boulanger, Karen T; Joshi, Milind; Pan, Yann Ping; Chang, Ruey-Kang R

2010-09-28

Congenital heart disease, a common and serious birth defect, affects 8 per 1000 live-born infants. Decreased exercise capacity and development of obesity is common in this population. These children may benefit from therapies, such as massage therapy, that could enhance cardiovascular and skeletal muscle function when they exercise. A pilot study conducted at the pediatric cardiology clinic of the Mattel Children's Hospital of the University of California-Los Angeles examined the safety and feasibility of measuring the effects of pre-exercise massage on exercise performance and cardiopulmonary response in children with and without heart disease. SIXTEEN CHILDREN (MEAN AGE: 9.2 ± 2.2 years) participated in the study. Ten participants had various forms of heart disease, and six children were healthy. A female certified massage therapist with specialized training in pediatric massage provided a 30-minute massage to the participants. Using a standard protocol, each participant underwent two exercise tests: one test with and one without pre-exercise massage. Heart rate, blood pressure, and oxygen uptake (VO(2)) were measured in the participants. All recruited participants completed the study. No adverse events occurred during any of the exercise tests or massage sessions. Measurements during exercise with or without a preceding massage were compared, and the pre-exercise massage condition yielded a significantly higher heart rate and higher minute ventilation. Measurements during exercise in children with heart disease and in healthy participants showed no significant differences in peak heart rate, blood pressure, peak VO(2), peak work rate, minute ventilation, or respiratory quotient. In this study, peak heart rate, peak VO(2), and peak minute ventilation were higher when children received a massage before exercise testing. Larger studies will be needed to investigate the strength of this finding. Future studies should include measurements of anxiety and psychological factors in addition to cardiopulmonary measures.

The Effects of Acute Exercise on Memory and Brain-Derived Neurotrophic Factor (BDNF).

PubMed

Etnier, Jennifer L; Wideman, Laurie; Labban, Jeffrey D; Piepmeier, Aaron T; Pendleton, Daniel M; Dvorak, Kelly K; Becofsky, Katie

2016-08-01

Acute exercise benefits cognition, and some evidence suggests that brain-derived neurotrophic factor (BDNF) plays a role in this effect. The purpose of this study was to explore the dose-response relationship between exercise intensity, memory, and BDNF. Young adults completed 3 exercise sessions at different intensities relative to ventilator threshold (Vt) (VO 2max , Vt - 20%, Vt + 20%). For each session, participants exercised for approximately 30 min. Following exercise, they performed the Rey Auditory Verbal Learning Test (RAVLT) to assess short-term memory, learning, and long-term memory recall. Twenty-four hours later, they completed the RAVLT recognition trial, which provided another measure of long-term memory. Blood was drawn before exercise, immediately postexercise, and after the 30-min recall test. Results indicated that long-term memory as assessed after the 24-hr delay differed as a function of exercise intensity with the largest benefits observed following maximal intensity exercise. BDNF data showed a significant increase in response to exercise; however, there were no differences relative to exercise intensity and there were no significant associations between BDNF and memory. Future research is warranted so that we can better understand how to use exercise to benefit cognitive performance.

Clinical test responses to different orthoptic exercise regimes in typical young adults.

PubMed

Horwood, Anna; Toor, Sonia

2014-03-01

The relative efficiency of different eye exercise regimes is unclear, and in particular the influences of practice, placebo and the amount of effort required are rarely considered. This study measured conventional clinical measures following different regimes in typical young adults. A total of 156 asymptomatic young adults were directed to carry out eye exercises three times daily for 2 weeks. Exercises were directed at improving blur responses (accommodation), disparity responses (convergence), both in a naturalistic relationship, convergence in excess of accommodation, accommodation in excess of convergence, and a placebo regime. They were compared to two control groups, neither of which were given exercises, but the second of which were asked to make maximum effort during the second testing. Instruction set and participant effort were more effective than many exercises. Convergence exercises independent of accommodation were the most effective treatment, followed by accommodation exercises, and both regimes resulted in changes in both vergence and accommodation test responses. Exercises targeting convergence and accommodation working together were less effective than those where they were separated. Accommodation measures were prone to large instruction/effort effects and monocular accommodation facility was subject to large practice effects. Separating convergence and accommodation exercises seemed more effective than exercising both systems concurrently and suggests that stimulation of accommodation and convergence may act in an additive fashion to aid responses. Instruction/effort effects are large and should be carefully controlled if claims for the efficacy of any exercise regime are to be made. © 2014 The Authors Ophthalmic & Physiological Optics published by John Wiley & Sons Ltd on behalf of The College of Optometrists.

Exercise in Patients on Dialysis: A Multicenter, Randomized Clinical Trial.

PubMed

Manfredini, Fabio; Mallamaci, Francesca; D'Arrigo, Graziella; Baggetta, Rossella; Bolignano, Davide; Torino, Claudia; Lamberti, Nicola; Bertoli, Silvio; Ciurlino, Daniele; Rocca-Rey, Lisa; Barillà, Antonio; Battaglia, Yuri; Rapanà, Renato Mario; Zuccalà, Alessandro; Bonanno, Graziella; Fatuzzo, Pasquale; Rapisarda, Francesco; Rastelli, Stefania; Fabrizi, Fabrizio; Messa, Piergiorgio; De Paola, Luciano; Lombardi, Luigi; Cupisti, Adamasco; Fuiano, Giorgio; Lucisano, Gaetano; Summaria, Chiara; Felisatti, Michele; Pozzato, Enrico; Malagoni, Anna Maria; Castellino, Pietro; Aucella, Filippo; Abd ElHafeez, Samar; Provenzano, Pasquale Fabio; Tripepi, Giovanni; Catizone, Luigi; Zoccali, Carmine

2017-04-01

Previous studies have suggested the benefits of physical exercise for patients on dialysis. We conducted the Exercise Introduction to Enhance Performance in Dialysis trial, a 6-month randomized, multicenter trial to test whether a simple, personalized walking exercise program at home, managed by dialysis staff, improves functional status in adult patients on dialysis. The main study outcomes included change in physical performance at 6 months, assessed by the 6-minute walking test and the five times sit-to-stand test, and in quality of life, assessed by the Kidney Disease Quality of Life Short Form (KDQOL-SF) questionnaire. We randomized 296 patients to normal physical activity (control; n =145) or walking exercise ( n =151); 227 patients (exercise n =104; control n =123) repeated the 6-month evaluations. The distance covered during the 6-minute walking test improved in the exercise group (mean distance±SD: baseline, 328±96 m; 6 months, 367±113 m) but not in the control group (baseline, 321±107 m; 6 months, 324±116 m; P <0.001 between groups). Similarly, the five times sit-to-stand test time improved in the exercise group (mean time±SD: baseline, 20.5±6.0 seconds; 6 months, 18.2±5.7 seconds) but not in the control group (baseline, 20.9±5.8 seconds; 6 months, 20.2±6.4 seconds; P =0.001 between groups). The cognitive function score ( P =0.04) and quality of social interaction score ( P =0.01) in the kidney disease component of the KDQOL-SF improved significantly in the exercise arm compared with the control arm. Hence, a simple, personalized, home-based, low-intensity exercise program managed by dialysis staff may improve physical performance and quality of life in patients on dialysis. Copyright © 2017 by the American Society of Nephrology.

Cholinergic stimulation with pyridostigmine protects against exercise induced myocardial ischaemia

PubMed Central

Castro, R R T; Porphirio, G; Serra, S M; Nóbrega, A C L

2004-01-01

Objective: To determine the acute effects of pyridostigmine bromide, a reversible cholinesterase inhibitor, during exercise in patients with coronary artery disease. Design: Double blind, randomised, placebo controlled, crossover study. Setting: Outpatients evaluated in an exercise test laboratory. Patients: 15 patients with exercise induced myocardial ischaemia. Interventions: Maximal cardiopulmonary exercise test on a treadmill according to an individualised ramp protocol on three days. The first day was used for adaptation to the equipment and to determine exercise tolerance and the presence of exercise induced ischaemia. On the other two days, the cardiopulmonary exercise test was performed two hours after oral administration of pyridostigmine (45 mg) or placebo. All patients were taking their usual medication during the experiments. Main outcome measures: Rate–pressure product and oxygen uptake during exercise. Results: Pyridostigmine inhibited the submaximum chronotropic response (p  =  0.001), delaying the onset of myocardial ischaemia, which occurred at a similar rate–pressure product (mean (SE) placebo 20.55 (1.08) mm Hg × beats/min 103; pyridostigmine 19.75 (1.28) mm Hg × beats/min 103; p  =  0.27) but at a higher exercise intensity (oxygen consumption: placebo 18.6 (1.7) ml/kg/min; pyridostigmine 19.6 (1.8) ml/kg/min; p  =  0.03). Also, pyridostigmine increased peak oxygen consumption (placebo 23.6 (2) ml/kg/min; pyridostigmine 24.8 (2) ml/kg/min; p  =  0.01) and peak oxygen pulse (placebo 12.9 (1) ml/beat; pyridostigmine 13.6 (1) ml/beat; p  =  0.02). Conclusions: Pyridostigmine improved peak exercise tolerance and inhibited the chronotropic response to submaximum exercise, increasing the intensity at which myocardial ischaemia occurred. These results suggest that pyridostigmine can protect against exercise induced myocardial ischaemia. PMID:15367503

Cardiovascular mortality prediction in veterans with arm exercise vs pharmacologic myocardial perfusion imaging.

PubMed

Martin, Wade H; Xian, Hong; Chandiramani, Pooja; Bainter, Emily; Klein, Andrew J P

2015-08-01

No data exist comparing outcome prediction from arm exercise vs pharmacologic myocardial perfusion imaging (MPI) stress test variables in patients unable to perform treadmill exercise. In this retrospective study, 2,173 consecutive lower extremity disabled veterans aged 65.4 ± 11.0years (mean ± SD) underwent either pharmacologic MPI (1730 patients) or arm exercise stress tests (443 patients) with MPI (n = 253) or electrocardiography alone (n = 190) between 1997 and 2002. Cox multivariate regression models and reclassification analysis by integrated discrimination improvement (IDI) were used to characterize stress test and MPI predictors of cardiovascular mortality at ≥10-year follow-up after inclusion of significant demographic, clinical, and other variables. Cardiovascular death occurred in 561 pharmacologic MPI and 102 arm exercise participants. Multivariate-adjusted cardiovascular mortality was predicted by arm exercise resting metabolic equivalents (hazard ratio [HR] 0.52, 95% CI 0.39-0.69, P < .001), 1-minute heart rate recovery (HR 0.61, 95% CI 0.44-0.86, P < .001), and pharmacologic and arm exercise delta (peak-rest) heart rate (both P < .001). Only an abnormal arm exercise MPI prognosticated cardiovascular death by multivariate Cox analysis (HR 1.98, 95% CI 1.04-3.77, P < .05). Arm exercise MPI defect number, type, and size provided IDI over covariates for prediction of cardiovascular mortality (IDI = 0.074-0.097). Only pharmacologic defect size prognosticated cardiovascular mortality (IDI = 0.022). Arm exercise capacity, heart rate recovery, and pharmacologic and arm exercise heart rate responses are robust predictors of cardiovascular mortality. Arm exercise MPI results are equivalent and possibly superior to pharmacologic MPI for cardiovascular mortality prediction in patients unable to perform treadmill exercise. Published by Elsevier Inc.

The protective effects of free wheel-running against cocaine psychomotor sensitization persist after exercise cessation in C57BL/6J mice.

PubMed

Lespine, L-F; Tirelli, E

2015-12-03

Previous literature suggests that free access to a running wheel can attenuate the behavioral responsiveness to addictive drugs in rodents. In a few studies, wheel-running cessation accentuated drug responsiveness. Here, we tested whether free wheel-running cessation is followed by (1) an accentuation or (2) an attenuation of cocaine psychomotor sensitization, knowing that no cessation of (continuous) wheel-running is associated with an attenuation of cocaine responsiveness. Male C57BL/6J mice, aged 35 days, were housed singly either with (exercising mice) or without (non-exercising mice) a running wheel. At the end of a period of 36 days, half of the exercising mice were deprived of their wheel whereas the other half of exercising mice kept their wheel until the end of experimentation (which lasted 85 days). The non-exercising mice were housed without wheel throughout experimentation. Testing took place 3 days after exercise cessation. After 2 once-daily drug-free test sessions, mice were tested for initiation of psychomotor sensitization over 13 once-daily injections of 8 mg/kg cocaine. Post-sensitization conditioned activation (saline challenge) and long-term expression of sensitization were assessed 2 or 30 days after the last sensitizing injection (same treatments as for initiation of sensitization), respectively. Exercising mice and mice undergoing wheel-running cessation exhibited comparable degrees of attenuation of all cocaine effects in comparison with the continuously non-exercising mice, which showed the greatest effects. Thus, the efficaciousness of wheel-running at attenuating cocaine sensitization not only resisted to exercise cessation but was also unambiguously persistent (an important effect rarely reported in previous literature). Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Short-term ubiquinol supplementation reduces oxidative stress associated with strenuous exercise in healthy adults: A randomized trial.

PubMed

Sarmiento, Alvaro; Diaz-Castro, Javier; Pulido-Moran, Mario; Moreno-Fernandez, Jorge; Kajarabille, Naroa; Chirosa, Ignacio; Guisado, Isabel M; Javier Chirosa, Luis; Guisado, Rafael; Ochoa, Julio J

2016-11-12

Studies about Coenzyme Q 10 (CoQ 10 ) supplementation on strenuous exercise are scarce, especially those related with oxidative stress associated with physical activity and virtually nonexistent with the reduced form, Ubiquinol. The objective of this study was to determine, for the first time, whether a short-term supplementation with Ubiquinol can prevent oxidative stress associated to strenuous exercise. The participants (n = 100 healthy and well trained, but not on an elite level) were classified in two groups: Ubiquinol (experimental group), and placebo group (control). The protocol consisted of conducting two identical strenuous exercise tests with a rest period between tests of 24 h. Blood and urine samples were collected from the participants before supplementation (basal value) (T1), after supplementation (2 weeks) (T2), after first physical exercise test (T3), after 24 h of rest (T4), and after second physical exercise test (T5).The increase observed in the lactate, isoprostanes, DNA damage, and hydroperoxide levels reveals the severity of the oxidative damage induced by the exercise. There was a reduction in the isoprostanes, 8-OHdG, oxidized LDL, and hydroperoxydes in the supplemented Ubiquinol group, an increase in total antioxidant status, fat soluble antioxidant (both plasma and membrane), and CAT activity. Also, NO in the Ubiquinol-supplemented group was maintained within a narrow range. Oxidative stress induced by strenuous exercise is accumulative and increases transiently in subsequent sessions of physical activity. A short-term supplementation (2 weeks) with Ubiquinol (200 mg/day) before strenuous exercise, decreases oxidative stress and increases plasma NO, fact that could improve endothelial function, energetic substrate supply, and muscle recovery after strenuous exercise. © 2016 BioFactors, 42(6):612-622, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

Eryptosis and hemorheological responses to maximal exercise in athletes: Comparison between running and cycling.

PubMed

Nader, E; Guillot, N; Lavorel, L; Hancco, I; Fort, R; Stauffer, E; Renoux, C; Joly, P; Germain, M; Connes, P

2018-05-01

We compared the effects of cycling and running exercise on hemorheological and hematological properties, as well as eryptosis markers. Seven endurance-trained subjects randomly performed a progressive and maximal exercise test on a cycle ergometer and a treadmill. Blood was sampled at rest and at the end of the exercise to analyze hematological and blood rheological parameters including hematocrit (Hct), red blood cell (RBC) deformability, aggregation, and blood viscosity. Hemoglobin saturation (SpO2), blood lactate, and glucose levels were also monitored. Red blood cell oxidative stress, calcium content, and phosphatidylserine exposure were determined by flow cytometry to assess eryptosis level. Cycling exercise increased blood viscosity and RBC aggregation whereas it had no significant effect on RBC deformability. In contrast, blood viscosity remained unchanged and RBC deformability increased with running. The increase in Hct, lactate, and glucose concentrations and the loss of weight at the end of exercise were not different between running and cycling. Eryptosis markers were not affected by exercise. A significant drop in SpO2 was noted during running but not during cycling. Our study showed that a progressive and maximal exercise test conducted on a cycle ergometer increased blood viscosity while the same test conducted on a treadmill did not change this parameter because of different RBC rheological behavior between the 2 tests. We also demonstrated that a short maximal exercise does not alter RBC physiology in trained athletes. We suspect that exercise-induced hypoxemia occurring during running could be at the origin of the RBC rheological behavior differences with cycling. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Functional training improves club head speed and functional fitness in older golfers.

PubMed

Thompson, Christian J; Cobb, Karen Myers; Blackwell, John

2007-02-01

Functional training programs have been used in a variety of rehabilitation settings with documented success. Based on that success, the concept of functional training has gained popularity in applied fitness settings to enhance sport performance. However, there has been little or no research studying the efficacy of functional training programs on the improvement of sport performance or functional fitness. Thus, it was the purpose of this study to determine the effect of a progressive functional training program on club head speed and functional fitness in older male golfers. Eighteen male golfers (age: 70.7 +/- 9.1 [SD] years) were randomly assigned to an exercise (N = 11) or control (N = 7) group. The exercise group participated in an 8-week progressive functional training program including flexibility exercises, core stability exercises, balance exercises, and resistance exercises. Pre- and postmeasurements included club head speed of a driver by radar (exercise and Control) and Fullerton Senior Fitness Test measurements (exercise only). One-way analysis of covariance was performed on club head speed measurements using pretest measurements as the covariate. Paired t-tests were performed to analyze Senior Fitness Test variables. After the intervention, maximal club head speed increased in the exercise group (127.3 +/- 13.4 to 133.6 +/- 14.2 km x hr(-1)) compared with the control group (134.5 +/- 14.6 to 133.3 +/- 11.2 km x hr(-1); p < 0.05). Additionally, improvements (p < 0.05) were detected for most Senior Fitness Test variables in the exercise group. In summary, this functional training program resulted in significant improvements in club head speed and several components of functional fitness. Future research should continue to examine the effect of functional training programs on sport performance and functional fitness in older adults.

Exercise-induced oxyhaemoglobin desaturation, ventilatory limitation and lung diffusing capacity in women during and after exercise.

PubMed

Walls, Justin; Maskrey, Michael; Wood-Baker, Richard; Stedman, Wade

2002-06-01

Arterial haemoglobin saturation during exercise in healthy young women [eight subjects mean (SEM) age 20.8 (1.8) years] was measured to confirm the theory that young women experience exercise-induced arterial hypoxaemia (EIAH) at a lower relative percentage of maximal oxygen uptake (VO(2max)) than has been documented in their male counterparts. To determine if flow limitation [the percentage of the tidal volume ( V(T)) that met or exceeded the boundary established by multiple maximal expiratory manoeuvres] and/or post-exercise lung diffusing capacity are linked to EIAH in women, and to investigate the influence of exercise intensity and duration on post-exercise carbon monoxide lung diffusing capacity ( D(L, CO)), these parameters were measured during and after three exercise tests (incremental test until exhaustion, 5 km run and 5 km run with sprint). All subjects experienced physiologically significant EIAH (a fall of more than 3% in oxygen saturation of arterial blood from levels at rest) and seven subjects experienced flow limitation during the VO(2max) protocol [mean (SD) 12.2 (8.8)% of V(T)]. Even though there was no significant relationship between aerobic capacity and the degree of flow limitation ( r=0.33, P>0.05), the flow limitation was related to absolute ventilation in the subjects studied ( r=0.82, P<0.05). There was no significant relationship between decrements in post exercise D(L, CO) and EIAH ( r=0.05, P>0.05), however there was a strong correlation between the extent of flow limitation (% of V(T)) and EIAH ( r=0.71). Significant decreases in D(L, CO) lasted for up to 16 h after each of the exercise tests ( P<0.05) and lasted for a further 8 h after the maximal test ( P<0.05). Exercise intensity was the main contributing factor to the observed decreases in post-exercise D(L, CO) with the percentage of VO(2max) attained during the various tests being significantly related to the fall in D(L, CO) for 1, 2, 3, 16 and 24 h after exercise ( P<0.05). As the appearance of flow limitation closely coincided with the appearance of EIAH, the results from the present study suggest that flow limitation is a contributing factor to EIAH in women although the exact mechanism remains unclear.

Qualified Fitness and Exercise as Professionals and Exercise Prescription: Evolution of the PAR-Q and Canadian Aerobic Fitness Test.

PubMed

Shephard, Roy J

2015-04-01

Traditional approaches to exercise prescription have included a preliminary medical screening followed by exercise tests of varying sophistication. To maximize population involvement, qualified fitness and exercise professionals (QFEPs) have used a self-administered screening questionnaire (the Physical Activity Readiness Questionnaire, PAR-Q) and a simple measure of aerobic performance (the Canadian Aerobic Fitness Test, CAFT). However, problems have arisen in applying the original protocol to those with chronic disease. Recent developments have addressed these issues. Evolution of the PAR-Q and CAFT protocol is reviewed from their origins in 1974 to the current electronic decision tree model of exercise screening and prescription. About a fifth of apparently healthy adults responded positively to the original PAR-Q instrument, thus requiring an often unwarranted referral to a physician. Minor changes of wording did not overcome this problem. However, a consensus process has now developed an electronic decision tree for stratification of exercise risk not only for healthy individuals, but also for those with various types of chronic disease. The new approach to clearance greatly reduces physician referrals and extends the role of QFEPs. The availability of effective screening and simple fitness testing should contribute to the goal of maximizing physical activity in the entire population.

Studies with the USF/NASA toxicity screening test method - Exercise wheels and oxygen replenishment

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Cumming, H. J.

1977-01-01

Continuing efforts to improve the University of San Francisco/NASA toxicity screening test method have included the addition of exercise wheels to provide a different measure of incapacitation, and oxygen replenishment to offset any effect of oxygen depletion by the test animals. The addition of exercise wheels limited the number of animals in each test and doubled the required number of tests without any significant improvement in reproducibility. Oxygen replenishment appears to have an effect on survival in the last 5 minutes of the 30-minute test, but the effect is expected to be similar for most materials.

Clinical use of submaximal treadmill exercise testing and assessments of cardiac biomarkers NT-proBNP and cTnI in dogs with presymptomatic mitral regurgitation

PubMed Central

Wall, Leona; Mohr, Annika; Ripoli, Florenza Lüder; Schulze, Nayeli; Penter, Camila Duarte; Hungerbuehler, StephanOscar; Bach, Jan-Peter; Lucas, Karin

2018-01-01

Exercise intolerance is the first symptom of heart disease. Yet an objective and standardised method in canine cardiology to assess exercise capacity in a clinical setting is lacking. In contrast, exercise testing is a powerful diagnostic tool in humans, providing valuable information on prognosis and impact of therapeutic intervention. To investigate whether an exercise test reveals differences between dogs with early stage mitral regurgitation (MR) and dogs without cardiac disease, 12 healthy beagles (healthy group, HG) and 12 dogs with presymptomatic MR (CHIEF B1 / B2, patient group, PG) underwent a six-stage submaximal exercise test (ET) on a motorised treadmill. They trotted in their individual comfort speed for three minutes per stage, first without incline, afterwards increasing it by 4% for every subsequent stage. Blood samples were taken at rest and during two 3-minute breaks in the course of the test. Further samples were taken after the completion of the exercise test and again after a 3-hour recovery period. Measured parameters included heart rate, lactate and the cardiac biomarkers N-terminal pro-B-Type natriuretic peptide and cardiac Troponin I. The test was performed again under the same conditions in the same dogs three weeks after the first trial to evaluate individual repeatability. Cardiac biomarkers increased significantly in both HG and PG in the course of the test. The increase was more pronounced in CHIEF B1 / B2 dogs than in the HG. N-terminal pro-B-Type natriuretic peptide increased from 435 ± 195 to 523 ± 239 pmol/L (HG) and from 690 to 815 pmol/L (PG). cTnI increased from 0.020 to 0.024 ng/mL (HG) and from 0.06 to 0.08 ng/ml (PG). The present study provides a method to assess exercise-induced changes in cardiac biomarkers under clinical conditions. The increase of NT-proBNP and cTnI is more pronounced in dogs with early-stage MR than in healthy dogs. Results indicate that measuring the parameters before and after exercise is adequate and taking blood samples between the different stages of the ET does not provide additional information. Also, stress echocardiography was inconclusive. It can be concluded that exercise testing, especially in combination with measuring cardiac biomarkers, could be a helpful diagnostic tool in canine cardiology. PMID:29902265

Clinical use of submaximal treadmill exercise testing and assessments of cardiac biomarkers NT-proBNP and cTnI in dogs with presymptomatic mitral regurgitation.

PubMed

Wall, Leona; Mohr, Annika; Ripoli, Florenza Lüder; Schulze, Nayeli; Penter, Camila Duarte; Hungerbuehler, StephanOscar; Bach, Jan-Peter; Lucas, Karin; Nolte, Ingo

2018-01-01

Exercise intolerance is the first symptom of heart disease. Yet an objective and standardised method in canine cardiology to assess exercise capacity in a clinical setting is lacking. In contrast, exercise testing is a powerful diagnostic tool in humans, providing valuable information on prognosis and impact of therapeutic intervention. To investigate whether an exercise test reveals differences between dogs with early stage mitral regurgitation (MR) and dogs without cardiac disease, 12 healthy beagles (healthy group, HG) and 12 dogs with presymptomatic MR (CHIEF B1 / B2, patient group, PG) underwent a six-stage submaximal exercise test (ET) on a motorised treadmill. They trotted in their individual comfort speed for three minutes per stage, first without incline, afterwards increasing it by 4% for every subsequent stage. Blood samples were taken at rest and during two 3-minute breaks in the course of the test. Further samples were taken after the completion of the exercise test and again after a 3-hour recovery period. Measured parameters included heart rate, lactate and the cardiac biomarkers N-terminal pro-B-Type natriuretic peptide and cardiac Troponin I. The test was performed again under the same conditions in the same dogs three weeks after the first trial to evaluate individual repeatability. Cardiac biomarkers increased significantly in both HG and PG in the course of the test. The increase was more pronounced in CHIEF B1 / B2 dogs than in the HG. N-terminal pro-B-Type natriuretic peptide increased from 435 ± 195 to 523 ± 239 pmol/L (HG) and from 690 to 815 pmol/L (PG). cTnI increased from 0.020 to 0.024 ng/mL (HG) and from 0.06 to 0.08 ng/ml (PG). The present study provides a method to assess exercise-induced changes in cardiac biomarkers under clinical conditions. The increase of NT-proBNP and cTnI is more pronounced in dogs with early-stage MR than in healthy dogs. Results indicate that measuring the parameters before and after exercise is adequate and taking blood samples between the different stages of the ET does not provide additional information. Also, stress echocardiography was inconclusive. It can be concluded that exercise testing, especially in combination with measuring cardiac biomarkers, could be a helpful diagnostic tool in canine cardiology.

Validity of a Newly-Designed Rectilinear Stepping Ergometer Submaximal Exercise Test to Assess Cardiorespiratory Fitness.

PubMed

Zhang, Rubin; Zhan, Likui; Sun, Shaoming; Peng, Wei; Sun, Yining

2017-09-01

The maximum oxygen uptake (V̇O 2 max), determined from graded maximal or submaximal exercise tests, is used to classify the cardiorespiratory fitness level of individuals. The purpose of this study was to examine the validity and reliability of the YMCA submaximal exercise test protocol performed on a newly-designed rectilinear stepping ergometer (RSE) that used up and down reciprocating vertical motion in place of conventional circular motion and giving precise measurement of workload, to determine V̇O 2 max in young healthy male adults. Thirty-two young healthy male adults (32 males; age range: 20-35 years; height: 1.75 ± 0.05 m; weight: 67.5 ± 8.6 kg) firstly participated in a maximal-effort graded exercise test using a cycle ergometer (CE) to directly obtain measured V̇O 2 max. Subjects then completed the progressive multistage test on the RSE beginning at 50W and including additional stages of 70, 90, 110, 130, and 150W, and the RSE YMCA submaximal test consisting of a workload increase every 3 minutes until the termination criterion was reached. A metabolic equation was derived from the RSE multistage exercise test to predict oxygen consumption (V̇O 2 ) from power output (W) during the submaximal exercise test (V̇O 2 (mL·min -1 )=12.4 ×W(watts)+3.5 mL·kg -1 ·min -1 ×M+160mL·min -1 , R 2 = 0.91, standard error of the estimate (SEE) = 134.8mL·min -1 ). A high correlation was observed between the RSE YMCA estimated V̇O 2 max and the CE measured V̇O 2 max (r=0.87). The mean difference between estimated and measured V̇O 2 max was 2.5 mL·kg -1 ·min -1 , with an SEE of 3.55 mL·kg -1 ·min -1 . The data suggest that the RSE YMCA submaximal exercise test is valid for predicting V̇O 2 max in young healthy male adults. The findings show that the rectilinear stepping exercise is an effective submaximal exercise for predicting V̇O 2 max. The newly-designed RSE may be potentially further developed as an alternative ergometer for assessing cardiorespiratory fitness and the promotion of personalized health interventions for health care professionals.

The role of targeted therapy in the management of patients with AML

PubMed Central

2017-01-01

Drug therapy for acute myeloid leukemia (AML) is finally undergoing major changes in 2017. This is due to the US Food and Drug Administration’s approval of several new, targeted agents (midostaurin, enasidenib, and gemtuzumab ozogamicin). Paired with the recent approval of a novel liposomal formulation of daunorubicin/cytarabine (CPX-351/Vyxeos), the standard of care is changing rapidly in AML for subgroups. This review will focus on currently approved agents and promising novel agents in development and will highlight controversial areas in targeted treatment. PMID:29296877

The role of targeted therapy in the management of patients with AML.

PubMed

Perl, Alexander E

2017-11-14

Drug therapy for acute myeloid leukemia (AML) is finally undergoing major changes in 2017. This is due to the US Food and Drug Administration's approval of several new, targeted agents (midostaurin, enasidenib, and gemtuzumab ozogamicin). Paired with the recent approval of a novel liposomal formulation of daunorubicin/cytarabine (CPX-351/Vyxeos), the standard of care is changing rapidly in AML for subgroups. This review will focus on currently approved agents and promising novel agents in development and will highlight controversial areas in targeted treatment.

Fullerene-like CS x: A first-principles study of synthetic growth

NASA Astrophysics Data System (ADS)

Goyenola, C.; Gueorguiev, G. K.; Stafström, S.; Hultman, L.

2011-04-01

Fullerene-Like (FL) Sulpho-Carbide (CSx) compounds have been addressed by first principles calculations. Geometry optimization and cohesive energy results are presented for the relative stability of precursor species such as C2S, CS2, and C2S2 in isolated form. The energy cost for structural defects, arising from the substitution of C by S is also reported. Similar to previously synthesized FL-CNx and FL-CPx compounds, the pentagon, the double pentagon defects as well as the Stone-Wales defects are confirmed as energetically feasible in CSx compounds.

Reflective and Non-conscious Responses to Exercise Images

PubMed Central

Cope, Kathryn; Vandelanotte, Corneel; Short, Camille E.; Conroy, David E.; Rhodes, Ryan E.; Jackson, Ben; Dimmock, James A.; Rebar, Amanda L.

2018-01-01

Images portraying exercise are commonly used to promote exercise behavior and to measure automatic associations of exercise (e.g., via implicit association tests). The effectiveness of these promotion efforts and the validity of measurement techniques partially rely on the untested assumption that the images being used are perceived by the general public as portrayals of exercise that is pleasant and motivating. The aim of this study was to investigate how content of images impacted people's automatic and reflective evaluations of exercise images. Participants (N = 90) completed a response time categorization task (similar to the implicit association test) to capture how automatically people perceived each image as relevant to Exercise or Not exercise. Participants also self-reported their evaluations of the images using visual analog scales with the anchors: Exercise/Not exercise, Does not motivate me to exercise/Motivates me to exercise, Pleasant/Unpleasant, and Energizing/Deactivating. People tended to more strongly automatically associate images with exercise if the images were of an outdoor setting, presented sport (as opposed to active labor or gym-based) activities, and included young (as opposed to middle-aged) adults. People tended to reflectively find images of young adults more motivating and relevant to exercise than images of older adults. The content of exercise images is an often overlooked source of systematic variability that may impact measurement validity and intervention effectiveness. PMID:29375419

Reflective and Non-conscious Responses to Exercise Images.

PubMed

Cope, Kathryn; Vandelanotte, Corneel; Short, Camille E; Conroy, David E; Rhodes, Ryan E; Jackson, Ben; Dimmock, James A; Rebar, Amanda L

2017-01-01

Images portraying exercise are commonly used to promote exercise behavior and to measure automatic associations of exercise (e.g., via implicit association tests). The effectiveness of these promotion efforts and the validity of measurement techniques partially rely on the untested assumption that the images being used are perceived by the general public as portrayals of exercise that is pleasant and motivating. The aim of this study was to investigate how content of images impacted people's automatic and reflective evaluations of exercise images. Participants ( N = 90) completed a response time categorization task (similar to the implicit association test) to capture how automatically people perceived each image as relevant to Exercise or Not exercise . Participants also self-reported their evaluations of the images using visual analog scales with the anchors: Exercise / Not exercise, Does not motivate me to exercise / Motivates me to exercise, Pleasant / Unpleasant , and Energizing/Deactivating . People tended to more strongly automatically associate images with exercise if the images were of an outdoor setting, presented sport (as opposed to active labor or gym-based) activities, and included young (as opposed to middle-aged) adults. People tended to reflectively find images of young adults more motivating and relevant to exercise than images of older adults. The content of exercise images is an often overlooked source of systematic variability that may impact measurement validity and intervention effectiveness.

Strength Recovery Following Rhythmic or Sustained Exercise as a Function of Time.

ERIC Educational Resources Information Center

Kearney, Jay T.

The relative rates of strength recovery subsequent to bouts of rhythmic or sustained isometric exercise were investigated. The 72 undergraduates who served as subjects were tested seven times within the framework of a repeated measures design. Each testing session involved two bouts of either rhythmic or sustained isometric exercise separated by a…

Effects of Exercise on Bone Mineral Content in Postmenopausal Women.

ERIC Educational Resources Information Center

Rikli, Roberta E.; McManis, Beth G.

1990-01-01

Study tested the effect of exercise programs on bone mineral content (BMC) and BMC/bone width in 31 postmenopausal women. Subjects were placed in groups with aerobic exercise, aerobics plus upper-body weight training, or no exercise. Results indicate that regular exercise programs positively affect bone mineral maintenance in postmenopausal women.…

Acute effects of exercise on the inflammatory state in patients with idiopathic pulmonary arterial hypertension.

PubMed

Harbaum, Lars; Renk, Emilia; Yousef, Sara; Glatzel, Antonia; Lüneburg, Nicole; Hennigs, Jan K; Oqueka, Tim; Baumann, Hans J; Atanackovic, Djordje; Grünig, Ekkehard; Böger, Rainer H; Bokemeyer, Carsten; Klose, Hans

2016-11-11

Exercise training positively influences exercise tolerance and functional capacity of patients with idiopathic pulmonary arterial hypertension (IPAH). However, the underlying mechanisms are unclear. We hypothesized that exercise modulates the activated inflammatory state found in IPAH patients. Single cardiopulmonary exercise testing was performed in 16 IPAH patients and 10 healthy subjects. Phenotypic characterization of peripheral blood mononuclear cells and circulating cytokines were assessed before, directly after and 1 h after exercise. Before exercise testing, IPAH patients showed elevated Th2 lymphocytes, regulatory T lymphocytes, IL-6, and TNF-alpha, whilst Th1/Th17 lymphocytes and IL-4 were reduced. In IPAH patients but not in healthy subject, exercise caused an immediate relative decrease of Th17 lymphocytes and a sustained reduction of IL-1-beta and IL-6. The higher the decrease of IL-6 the higher was the peak oxygen consumption of IPAH patients. Exercise seems to be safe from an immune and inflammatory point of view in IPAH patients. Our results demonstrate that exercise does not aggravate the inflammatory state and seems to elicit an immune-modulating effect in IPAH patients.

Gait, Balance, Leg Strength, and Sprint Speed After Bedrest with LBNP Exercise

NASA Technical Reports Server (NTRS)

Boda, Wanda L.; Watenbaugh, D. E.; Ballard, R. E.; Fortney, S. M.; Ertl, A. C.; Lee, S. M. C.; William, J. M.; Hargens, Alan R.

1997-01-01

Microgravity and bedrest (BR) result in similar physiological decrements such as loss of muscle mass, muscle strength and balance. Previous studies analyzing exercise within lower body negative pressure (LBNP) have found that gait is similar in LBNP on a vertical treadmill and overground exercise on a horizontal treadmill. Since treadmill exercise is known to increase muscular strength and endurance, we tested the hypothesis that LBNP exercise on a vertical treadmill would prevent or attenuate many of the physical decrements which occur during bedrest. Based on our positive results from diverse tests of post-BR function, we believe that exercise within LBNP is worth pursuing as a countermeasure for reducing the physical deterioration that occurs during bedrest and microgravity.

Maximising the clinical use of exercise gaseous exchange testing in children with repaired cyanotic congenital heart defects: the development of an appropriate test strategy.

PubMed

McManus, A; Leung, M

2000-04-01

Implicit in deciding upon an exercise test strategy to elucidate cardiopulmonary function in children with congenital heart disease are appropriate application of gas exchange techniques and the significance of the data collected to the specific congenital heart disorder. Post-operative cardiopulmonary responses to exercise in cyanotic disorders are complex and, despite a large body of extant literature in paediatric patients, there has been much difficulty in achieving quality and consistency of data. Maximal oxygen uptake is widely recognised as the best single indicator of cardiopulmonary function and has therefore been the focus of most clinical exercise tests in children. Many children with various heart anomalies are able to exercise to maximum without adverse symptoms, and it is essential that test termination is based on the same criteria for these children. Choosing appropriate, valid indicators of maximum in children with congenital heart disease is beset by difficulties. Such maximal intensity exercise testing procedures have been challenged on the grounds that they do not give a good indication of cardiopulmonary function that is relevant to real life situations. Furthermore, they are prone to much interindividual variability and error in the definition of maximal exertion. Alternative strategies have been proposed which focus upon dynamic submaximal and kinetic cardiopulmonary responses, which are thought to be less dependent on maximal voluntary effort and more suited to the daily activity patterns of children. These methods are also not without problems. Variability in anaerobic threshold measurements and controversy regarding its physiological meaning have been debated. It is recommended that an appropriate cardiopulmonary exercise gas exchange test strategy, which provides clinically useful information for children with cyanotic congenital heart disease, should include both maximal and submaximal data. The inclusion of oxygen uptake kinetics and ventilatory data are encouraged, since they may allow the distinction between a pulmonary, cardiovascular or inactivity related exercise limitation.

Step climbing capacity in patients with pulmonary hypertension.

PubMed

Fox, Benjamin Daniel; Langleben, David; Hirsch, Andrew; Boutet, Kim; Shimony, Avi

2013-01-01

Patients with pulmonary hypertension (PH) typically have exercise intolerance and limitation in climbing steps. To explore the exercise physiology of step climbing in PH patients, on a laboratory-based step test. We built a step oximetry system from an 'aerobics' step equipped with pressure sensors and pulse oximeter linked to a computer. Subjects mounted and dismounted from the step until their maximal exercise capacity or 200 steps was achieved. Step-count, SpO(2) and heart rate were monitored throughout exercise and recovery. We derived indices of exercise performance, desaturation and heart rate. A 6-min walk test and serum NT-proBrain Natriuretic Peptide (BNP) level were measured. Lung function tests and hemodynamic parameters were extracted from the medical record. Eighty-six subjects [52 pulmonary arterial hypertension (PAH), 14 chronic thromboembolic PH (CTEPH), 20 controls] were recruited. Exercise performance (climbing time, height gained, velocity, energy expenditure, work-rate and climbing index) on the step test was significantly worse with PH and/or worsening WHO functional class (ANOVA, p < 0.001). There was a good correlation between exercise performance on the step and 6-min walking distance-climb index (r = -0.77, p < 0.0001). The saturation deviation (mean of SpO(2) values <95 %) on the step test correlated with diffusion capacity of the lung (ρ = -0.49, p = 0.001). No correlations were found between the step test indices and other lung function tests, hemodynamic parameters or NT-proBNP levels. Patients with PAH/CTEPH have significant limitation in step climbing ability that correlates with functional class and 6-min walking distance. This is a significant impediment to their daily activities.

Factors that influence exercise activity among women post hip fracture participating in the Exercise Plus Program.

PubMed

Resnick, Barbara; Orwig, Denise; D'Adamo, Christopher; Yu-Yahiro, Janet; Hawkes, William; Shardell, Michelle; Golden, Justine; Zimmerman, Sheryl; Magaziner, Jay

2007-01-01

Using a social ecological model, this paper describes selected intra- and interpersonal factors that influence exercise behavior in women post hip fracture who participated in the Exercise Plus Program. Model testing of factors that influence exercise behavior at 2, 6 and 12 months post hip fracture was done. The full model hypothesized that demographic variables; cognitive, affective, physical and functional status; pain; fear of falling; social support for exercise, and exposure to the Exercise Plus Program would influence self-efficacy, outcome expectations, and stage of change both directly and indirectly influencing total time spent exercising. Two hundred and nine female hip fracture patients (age 81.0 +/- 6.9), the majority of whom were Caucasian (97%), participated in this study. The three predictive models tested across the 12 month recovery trajectory suggest that somewhat different factors may influence exercise over the recovery period and the models explained 8 to 21% of the variance in time spent exercising. To optimize exercise activity post hip fracture, older adults should be helped to realistically assess their self-efficacy and outcome expectations related to exercise, health care providers and friends/peers should be encouraged to reinforce the positive benefits of exercise post hip fracture, and fear of falling should be addressed throughout the entire hip fracture recovery trajectory.

Exercise barriers self-efficacy: development and validation of a subcale for individuals with cancer-related lymphedema.

PubMed

Buchan, Jena; Janda, Monika; Box, Robyn; Rogers, Laura; Hayes, Sandi

2015-03-18

No tool exists to measure self-efficacy for overcoming lymphedema-related exercise barriers in individuals with cancer-related lymphedema. However, an existing scale measures confidence to overcome general exercise barriers in cancer survivors. Therefore, the purpose of this study was to develop, validate and assess the reliability of a subscale, to be used in conjunction with the general barriers scale, for determining exercise barriers self-efficacy in individuals facing lymphedema-related exercise barriers. A lymphedema-specific exercise barriers self-efficacy subscale was developed and validated using a cohort of 106 cancer survivors with cancer-related lymphedema, from Brisbane, Australia. An initial ten-item lymphedema-specific barrier subscale was developed and tested, with participant feedback and principal components analysis results used to guide development of the final version. Validity and test-retest reliability analyses were conducted on the final subscale. The final lymphedema-specific subscale contained five items. Principal components analysis revealed these items loaded highly (>0.75) on a separate factor when tested with a well-established nine-item general barriers scale. The final five-item subscale demonstrated good construct and criterion validity, high internal consistency (Cronbach's alpha = 0.93) and test-retest reliability (ICC = 0.67, p < 0.01). A valid and reliable lymphedema-specific subscale has been developed to assess exercise barriers self-efficacy in individuals with cancer-related lymphedema. This scale can be used in conjunction with an existing general exercise barriers scale to enhance exercise adherence in this understudied patient group.

Discriminative validity of metabolic and workload measurements for identifying people with chronic fatigue syndrome.

PubMed

Snell, Christopher R; Stevens, Staci R; Davenport, Todd E; Van Ness, J Mark

2013-11-01

Reduced functional capacity and postexertion fatigue after physical activity are hallmark symptoms of chronic fatigue syndrome (CFS) and may even qualify for biomarker status. That these symptoms are often delayed may explain the equivocal results for clinical cardiopulmonary exercise testing in people with CFS. Test reproducibility in people who are healthy is well documented. Test reproducibility may not be achievable in people with CFS because of delayed symptoms. The objective of this study was to determine the discriminative validity of objective measurements obtained during cardiopulmonary exercise testing to distinguish participants with CFS from participants who did not have a disability but were sedentary. A prospective cohort study was conducted. Gas exchange data, workloads, and related physiological parameters were compared in 51 participants with CFS and 10 control participants, all women, for 2 maximal exercise tests separated by 24 hours. Multivariate analysis showed no significant differences between control participants and participants with CFS for test 1. However, for test 2, participants with CFS achieved significantly lower values for oxygen consumption and workload at peak exercise and at the ventilatory or anaerobic threshold. Follow-up classification analysis differentiated between groups with an overall accuracy of 95.1%. Only individuals with CFS who were able to undergo exercise testing were included in this study. Individuals who were unable to meet the criteria for maximal effort during both tests, were unable to complete the 2-day protocol, or displayed overt cardiovascular abnormalities were excluded from the analysis. The lack of any significant differences between groups for the first exercise test would appear to support a deconditioning hypothesis for CFS symptoms. However, the results from the second test indicated the presence of CFS-related postexertion fatigue. It might be concluded that a single exercise test is insufficient to reliably demonstrate functional impairment in people with CFS. A second test might be necessary to document the atypical recovery response and protracted fatigue possibly unique to CFS, which can severely limit productivity in the home and workplace.

Exercise testing in children with Wolff-Parkinson-White syndrome: what is its value?

PubMed

Dalili, M; Vahidshahi, K; Aarabi-Moghaddam, M Y; Rao, J Y; Brugada, P

2014-10-01

This study was conducted to evaluate the accuracy of exercise testing for predicting accessory pathway characteristics in children with Wolff-Parkinson-White (WPW) syndrome. The study enrolled 37 children with WPW syndrome and candidates for invasive electrophysiologic study (EPS). Exercise testing was performed for all the study participants before the invasive study. Data from the invasive EPS were compared with findings from the exercise testing. The sudden disappearance of the delta (Δ) wave was seen in 10 cases (27 %). No significant correlation was found between the Δ wave disappearance and the antegrade effective refractory period of the accessory pathway (AERP-AP) or the shortest pre-excited RR interval (SPERRI). The sensitivity, specificity, and positive and negative predictive values of Δ wave disappearance, based on AERP-AP as gold standard, were respectively 29.4, 80, 71.4, and 40 %. The corresponding values with SPERRI as the gold standard were respectively 23.8, 71.4, 71.4 and 23.8 %. Exercise testing has a medium to low rate of accuracy in detecting low-risk WPW syndrome patients in the pediatric age group.

Consensus on measurement properties and feasibility of performance tests for the exercise and sport sciences: a Delphi study.

PubMed

Robertson, Sam; Kremer, Peter; Aisbett, Brad; Tran, Jacqueline; Cerin, Ester

2017-12-01

Performance tests are used for multiple purposes in exercise and sport science. Ensuring that a test displays an appropriate level of measurement properties for use within a population is important to ensure confidence in test findings. The aim of this study was to obtain subject matter expert consensus on the measurement and feasibility properties that should be considered for performance tests used in the exercise and sport sciences and how these should be defined. This information was used to develop a checklist for broader dissemination. A two-round Delphi study was undertaken including 33 exercise scientists, academics and sport scientists. Participants were asked to rate the importance of a range of measurement properties relevant to performance tests in exercise and sport science. Responses were obtained in binary and Likert-scale formats, with consensus defined as achieving 67% agreement on each question. Consensus was reached on definitions and terminology for all items. Ten level 1 items (those that achieved consensus on all four questions) and nine level 2 items (those achieving consensus on ≥2 questions) were included. Both levels were included in the final checklist. The checklist developed from this study can be used to inform decision-making and test selection for practitioners and researchers in the exercise and sport sciences. This can facilitate knowledge sharing and performance comparisons across sub-disciplines, thereby improving existing field practice and research methodological quality.

Screening adolescent athletes for exercise-induced asthma.

PubMed

Feinstein, R A; LaRussa, J; Wang-Dohlman, A; Bartolucci, A A

1996-04-01

To pilot test an exercise-induced asthma (EIA) screening program using a submaximal step-test and pulmonary function test (PFT) to identify athletes with EIA and to determine if a physical examination or self-reported history could be used to predict the existence of EIA. Screening and diagnostic testing using a convenience sample. Birmingham, Alabama, during athletic preparticipation examination (PPE). Fifty-two African-American, male football players aged 14-18 years being evaluated for participation in scholastic athletics. No athlete refused participation. Four were excluded because of need for further evaluation unrelated to any pulmonary condition. Each athlete completed a medical history, allergy history, physical examination, preexercise pulmonary function test (PFT), submaximal step-test, and a series of postexercise PFTs. Major outcome measurements were changes in forced expiration volume in 1s (FEV1) or peak expiratory flow rate (PEFR) after completing an exercise challenge. Seventeen of 48 athletes had a > or = 15% decrease in PEFR after exercise. Nine of 48 athletes had a > or = 15% decrease in FEV1 after exercise. The only self-reported item that differentiated subjects with normal and abnormal PFTs was a personal history of asthma (p < 0.05). Many athletes can be identified as having abnormal PFTs by use of a submaximal step-test as an exercise challenge. Self-reporting questionnaires and PPEs do not appear to be sensitive enough to identify athletes with this condition. If validated by future studies, this protocol could be used for the diagnosis of EIA.

Exercise tolerance during VO2max testing is a multifactorial psychobiological phenomenon.

PubMed

Midgley, Adrian W; Earle, Keith; McNaughton, Lars R; Siegler, Jason C; Clough, Peter; Earle, Fiona

2017-01-01

Fifty-nine men completed a VO 2max test and a questionnaire to establish reasons for test termination, perceived exercise reserve (difference between actual test duration and the duration the individual perceived could have been achieved if continued until physical limitation), and perception of verbal encouragement. Participants gave between 1 and 11 factors as reasons for test termination, including leg fatigue, various perceptions of physical discomfort, safety concerns, and achievement of spontaneously set goals. The two most common main reasons were leg fatigue and breathing discomfort, which were predicted by pre-to-post test changes in pulmonary function (p = 0.038) and explosive leg strength (p = 0.042; R 2  = 0.40). Median (interquartile range) perceived exercise reserve, was 45 (50) s. Two-thirds of participants viewed verbal encouragement positively, whereas one-third had a neutral or negative perception. This study highlights the complexity of exercise tolerance during VO 2max testing and more research should explore these novel findings.

Acute Hematological and Inflammatory Responses to High-intensity Exercise Tests: Impact of Duration and Mode of Exercise.

PubMed

Minuzzi, Luciele G; Carvalho, Humberto M; Brunelli, Diego T; Rosado, Fatima; Cavaglieri, Cláudia R; Gonçalves, Carlos E; Gaspar, Joana M; Rama, Luís M; Teixeira, Ana M

2017-07-01

The purpose of this study was to investigate the hematological and inflammatory responses to 4 maximal high-intensity protocols, considering energy expenditure in each test. 9 healthy volunteers performed 4 high-intensity exercise tests of short [Wingate (WANT); Repeated-sprints (RSA)] and long durations [Continuous VO 2 test (VCONT); intermittent VO 2 test (VINT)] in a cycle-ergometer, until exhaustion. Hematological parameters and IL-6, IL-10 and creatine kinase (CK) levels were determined before (PRE), POST, 30 min, 1, 2, 12 and 24 h after the end of the protocols. Additionally, energy expenditure was determined. Leucocytes, erythrocytes and lymphocytes increased at POST and returned to PRE values at 30 min for all protocols. Lymphocytes had a second decreased at 2 h and granulocytes increased at 2 h when compared to PRE. Both variables returned to PRE values between 12-24 h into recovery. The magnitude of response for IL-6 was greater in VINT and for IL-10 in VCONT. There was no association of energy expenditure within each exercise protocol with the pattern of IL-6, IL-10 and CK responses to the exercise protocols. The present finding support that similar responses after continuous or intermittent acute protocols are observed when exercises are performed to volitional failure, regardless of the duration and mode of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Impact of a 10-Week Individualized Exercise Program on Physical Function and Fatigue of People with Multiple Sclerosis

PubMed Central

Elgelid, Staffan; Bolger, Shannon; Parsons, Caroline; Quashnoc, Rachel; Raymor, Johanna

2011-01-01

Research has found that people with multiple sclerosis (MS) who engage in exercise programs experience improvements in physical and psychological health, resulting in enhanced quality of life. These studies have involved structured exercise protocols, but few have examined the effects of an individualized exercise program allowing for peer socialization. The purpose of this study was to investigate the effects of a 10-week individualized exercise program offering opportunities to socialize with peers on fatigue and physical functioning in people with MS. Thirteen individuals with a physician diagnosis of MS were enrolled in a 10-week exercise program at Nazareth College in Rochester, New York. Eleven participants (9 female, 2 male; mean ± SD age, 55.0 ± 7.06 years) completed the study. The following qualitative and quantitative measures were used for evaluation before and after the exercise program: Multiple Sclerosis Quality of Life–54 (MSQOL-54), Activities-specific Balance Confidence (ABC) scale, Modified Fatigue Impact Scale (MFIS), Timed Up and Go (TUG) test, Timed 10-Meter Walk (T10MW) test, functional reach test, and single-leg stance (SLS) test. Statistically significant differences were found for the TUG (P = .005), T10MW (P = .014), and MFIS physical functioning subscore (P = .039). The results showed significant increases in gait speed and mobility as well as decreased impact of fatigue on physical functioning after the 10-week exercise program. PMID:24453715

Active Female Maximal and Anaerobic Threshold Cardiorespiratory Responses to Six Different Water Aerobics Exercises.

PubMed

Antunes, Amanda H; Alberton, Cristine L; Finatto, Paula; Pinto, Stephanie S; Cadore, Eduardo L; Zaffari, Paula; Kruel, Luiz F M

2015-01-01

Maximal tests conducted on land are not suitable for the prescription of aquatic exercises, which makes it difficult to optimize the intensity of water aerobics classes. The aim of the present study was to evaluate the maximal and anaerobic threshold cardiorespiratory responses to 6 water aerobics exercises. Volunteers performed 3 of the exercises in the sagittal plane and 3 in the frontal plane. Twelve active female volunteers (aged 24 ± 2 years) performed 6 maximal progressive test sessions. Throughout the exercise tests, we measured heart rate (HR) and oxygen consumption (VO2). We randomized all sessions with a minimum interval of 48 hr between each session. For statistical analysis, we used repeated-measures 1-way analysis of variance. Regarding the maximal responses, for the peak VO2, abductor hop and jumping jacks (JJ) showed significantly lower values than frontal kick and cross-country skiing (CCS; p < .001; partial η(2) = .509), while for the peak HR, JJ showed statistically significantly lower responses compared with stationary running and CCS (p < .001; partial η(2) = .401). At anaerobic threshold intensity expressed as the percentage of the maximum values, no statistically significant differences were found among exercises. Cardiorespiratory responses are directly associated with the muscle mass involved in the exercise. Thus, it is worth emphasizing the importance of performing a maximal test that is specific to the analyzed exercise so the prescription of the intensity can be safer and valid.

Effects of a Combined Exercise Program Using an iPad for Older Adults

PubMed Central

Lee, Juhee; Byun, Jinyee; Lee, Minkyung

2016-01-01

Objectives The purpose of this study was to examine the function, health status, and efficacy effects of a combined exercise program using an iPad among older women in Korea, a tech-savvy country. Methods The study employed a pretest and posttest experimental design with a control group. The experimental group of subjects comprised 16 female older adults and the control group comprised 10 who were aged 65 years or older. The experimental group participated in a supervised group-based exercise program and an individualized home-based exercise program that involved the use of an iPad. The combined group and home-based exercise program consisted of group exercise, which took place in a senior center for 30 minutes weekly, and a home-based iPad exercise program, which the subjects followed at least 3 times a week. The collected data were analyzed using the Statistical Analysis System (SAS ver. 9.3 TS Level 1M0) program, which utilized a chi-square test, a Fisher exact test, a t-test, and a repeated-measures ANOVA. Results The results showed that cognitive status changed significantly over time, and there was an interaction between group and time. Further, self-efficacy for exercise and outcome expectations for exercise changed significantly over time. Conclusions Exercise programs using iPad interventions may be useful for the management of cognitive functioning and the integration of functional physical abilities in older adults. PMID:27200215

Research to Encourage Exercise for Fibromyalgia (REEF): Use of Motivational Interviewing Design and Method

PubMed Central

Ang, Dennis C.; Kaleth, Anthony S.; Bigatti, Silvia; Mazzuca, Steve; Saha, Chandan; Hilligoss, Janna; Lengerich, Mimi; Bandy, Robert

2010-01-01

Fibromyalgia (FM), defined as the presence of both chronic widespread pain and the finding of 11/18 tender points on examination, is an illness associated with major personal and societal burden. Supervised aerobic exercise is an important treatment modality to improve patient symptoms. Unfortunately, adherence to an exercise regimen after a structured supervised program is disappointingly low. Since FM is a chronic illness, studies are needed to test strategies that would enhance exercise adherence in these individuals. Individuals who are able to adhere to exercise almost always maintain the symptomatic benefits of exercise. The objective of this paper was to describe the protocol of the Research to Encourage Exercise for Fibromyalgia (REEF). REEF is a randomized attention-controlled trial that seeks to test the efficacy of 6 sessions of telephone delivered motivational interviewing (MI) that targets exercise adherence to improve FM-relevant clinical outcomes (i.e., physical function and pain severity). The trial has recently completed enrolling 216 subjects, and randomization has resulted in well balanced groups. Details on the study design, MI program, and treatment fidelity are provided in the paper. Outcome assessments at week 12, week 24 and week 36 will test the immediate, intermediate and long term effects of exercise-based MI on adherence (as measured by the Community Health Activities Model Program for Seniors/CHAMPS and accelerometer) and clinical outcomes. When completed, REEF will determine whether exercise-based MI could be utilized as a management strategy to sustain the clinical benefits of exercise for FM. PMID:20828634

Research to Encourage Exercise for Fibromyalgia (REEF): use of motivational interviewing design and method.

PubMed

Ang, Dennis C; Kaleth, Anthony S; Bigatti, Silvia; Mazzuca, Steve; Saha, Chandan; Hilligoss, Janna; Lengerich, Mimi; Bandy, Robert

2011-01-01

Fibromyalgia (FM), defined as the presence of both chronic widespread pain and the finding of 11/18 tender points on examination, is an illness associated with major personal and societal burden. Supervised aerobic exercise is an important treatment modality to improve patient symptoms. Unfortunately, adherence to an exercise regimen after a structured supervised program is disappointingly low. Since FM is a chronic illness, studies are needed to test strategies that would enhance exercise adherence in these individuals. Individuals who are able to adhere to exercise almost always maintain the symptomatic benefits of exercise. The objective of this paper was to describe the protocol of the Research to Encourage Exercise for Fibromyalgia (REEF). REEF is a randomized attention-controlled trial that seeks to test the efficacy of 6 sessions of telephone delivered motivational interviewing (MI) that targets exercise adherence to improve FM-relevant clinical outcomes (i.e., physical function and pain severity). The trial has recently completed enrolling 216 subjects, and randomization has resulted in well-balanced groups. Details on the study design, MI program, and treatment fidelity are provided in the paper. Outcome assessments at week 12, week 24 and week 36 will test the immediate, intermediate and long-term effects of exercise-based MI on adherence (as measured by the Community Health Activities Model Program for Seniors/CHAMPS and accelerometer) and clinical outcomes. When completed, REEF will determine whether exercise-based MI could be utilized as a management strategy to sustain the clinical benefits of exercise for FM. Copyright © 2010 Elsevier Inc. All rights reserved.

Does core stability exercise improve lumbopelvic stability (through endurance tests) more than general exercise in chronic low back pain? A quasi-randomized controlled trial.

PubMed

Shamsi, Mohammad Bagher; Rezaei, Mandana; Zamanlou, Mehdi; Sadeghi, Mehdi; Pourahmadi, Mohammad Reza

2016-01-01

The aim was to compare core stability and general exercises (GEs) in chronic low back pain (LBP) patients based on lumbopelvic stability (LPS) assessment through three endurance core stability tests. There is a controversy about preference of core stability exercise (CSE) over other types of exercise for chronic LBP. Studies which have compared these exercises used other outcomes than those related to LPS. As it is claimed that CSE enhances back stability, endurance tests for LPS were used. A 16-session CSE program and a GE program with the same duration were conducted for two groups of participants. Frequency of interventions for both groups was three times a week. Forty-three people (aged 18-60 years) with chronic non-specific LBP were alternately allocated to core stability (n = 22) or GE group (n = 21) when admitted. The primary outcomes were three endurance core stability tests including: (1) trunk flexor; (2) trunk extensor; and (3) side bridge tests. Secondary outcomes were disability and pain. Measurements were taken at baseline and the end of the intervention. After the intervention, test times increased and disability and pain decreased within groups. There was no significant difference between two groups in increasing test times (p = 0.23 to p = 0.36) or decreasing disability (p = 0.16) and pain (p = 0.73). CSE is not more effective than GE for improving endurance core stability tests and reducing disability and pain in chronic non-specific LBP patients.

Effects of 4 month exercise on left ventricular remodeling and autonomic nervous system in hypertensive patients.

PubMed

Zheng, Huan; Xie, Nanzi; Xu, Huifeng; Huang, Junling; Xie, Xiaoyun; Luo, Ming

2016-03-01

We sought to investigate effects of supervised exercise training on left ventricular remodeling, left ventricular function and autonomic nervous system of hypertensive patients without medication. Fifty borderline and mildly hypertensive patients were enrolled and randomly divided into 2 groups (25 in each). Exercise group received a 4 months' exercise program, prescribed according to their first cardiopulmonary exercise tests, while the control group received routine dietary recommendation. All patients underwent noradrenalin assay, cardiopulmonary exercise tests and echocardiographic studies at enrollment and 4 month follow-up. At baseline no statistically difference between the two groups were observed in clinical characteristics, echographic variants or cardiopulmonary test index. Four months later, exercise group showed higher values of VO2peak, Powermax (max workload), AT (anaerobic threshold), VO2AT (VO2 at anaerobic threshold), tAT (time from beginning to anaerobic threshold) and heart rate recovery compared to the control group (P<0.05). Additionally, systolic/diastolic blood pressure decreased significantly in the exercise group compared to the control group (P<0.05). Moreover, there was significant reduction in left ventricular mass index in the exercise group (P<0.01), and there was also an inverse correlation between changes in left ventricular mass index and heart rate recovery (r=-0.52, P<0.01). Four-month exercise training in borderline and mildly hypertensive patients not only decreased their blood pressure levels, but also induced an improvement of exercise capability, left ventricular remodeling and heart rate recovery. Heart rate recovery improvement was significantly associated with decrease of left ventricular mass index, which indicated that favorable adjustment in autonomic nervous system of exercise training might be an important pathway to reverse left ventricular remodeling.

Short-term changes of serum potassium concentration induced by physical exercise in patient with arterial hypertension treated with angiotensin-converting enzyme inhibitor alone or in combination with statin.

PubMed

Deska, P; Nowicki, M

2017-02-01

Intensive physical exercise may facilitate potassium release from skeletal muscles that may result in hyperkalemia. Commonly used drugs including angiotensin converting enzyme inhibitors (ACEI) and statins increase a risk of hyperkalemia. It is not known whether the effect of these drugs on serum potassium during physical exercise is additive. The study compared the effect of physical exercise on the changes of serum potassium in hypertensive patients receiving ACEI alone or in combination with statin. Eighteen patients with arterial hypertension with normal renal function were included in a prospective placebo-controlled cross-over study. The patients underwent 3 exercise tests on a bicycle ergometer with 55 - 60% of maximum oxygen consumption each lasting 30 minutes, i.e. after being treated with ACEI alone for six months, and then in a random order after the administration of ACEI with statin or ACEI with placebo each time for eight weeks separated by 2-week wash-out. Serum potassium was measured with atomic emission flame spectrometry before and after 15 and 30 minutes exercise and after 30-minute recovery. During the exercise serum potassium concentration increased moderately but significantly during all exercise tests. Mean serum potassium during exercise remained within the normal range. There were no differences in the exercise-induced changes of serum potassium during the exercise tests performed after ACEI combined with statin or with placebo. Addition of statin to ACEI does not increase the risk of hyperkalemia in hypertensive patients with preserved renal function during physical exercise with intensity typical for routine daily activities.

76 FR 22809 - Safety Zone; Bay Ferry II Maritime Security Exercise; San Francisco Bay, San Francisco, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-25

...-AA00 Safety Zone; Bay Ferry II Maritime Security Exercise; San Francisco Bay, San Francisco, CA AGENCY... Security Exercise, a multi-agency exercise that tests the proficiency of teams called upon in real [[Page... exercise, many of whom will be traveling at high speeds while interfacing with law enforcement responders...

Comparison of Effects of Running and Playing Exercises on Differential Leucocyte Count in Young Elite Athletes

ERIC Educational Resources Information Center

Cenikli, Abdullah

2016-01-01

The aims of the present research are to test the effects of running and playing exercises on leucocyte and differential leucocyte accounts, and to test the possible differences between running and playing exercises in terms of leucocyte accounts. They were thirty two male young soccer players. Participants arrived at the laboratory after a 12-hour…

Self-Efficacy Manipulation Influences Physical Activity Enjoyment in Chinese Adolescents.

PubMed

Hu, Liang; Cheng, Shoubin; Lu, Jiaying; Zhu, Lele; Chen, Ling

2016-02-01

In this study, we examined the effect of the manipulation of exercise self-efficacy on the enjoyment of physical activity in a sample of 44 Chinese adolescents (age = 14.27 ± .87 y), including 22 boys and 22 girls. The participants were randomized into a low-efficacy or high-efficacy condition, and their self-efficacy beliefs for engaging in moderate-intensity physical activity were manipulated by providing false feedback after a submaximal exercise test. The participants' self-efficacy was measured and compared before and after the exercise test and the participants' enjoyment of physical activity was assessed after the exercise test. It was found that exercise self-efficacy was successfully manipulated in the expected direction in both conditions, which significantly influenced the participants' enjoyment of physical activity. After the exercise test, the participants in the low-efficacy condition reported lower enjoyment scores relative to the high-efficacy participants. These results suggest that self-efficacy may have an important influence on the enjoyment of physical activity among Chinese adolescents. We recommend that physical activity promotion programs should be tailored to enhance adolescents' self-efficacy beliefs and enjoyment of the experience of physical activity.

Determining the anaerobic threshold in water aerobic exercises: a comparison between the heart rate deflection point and the ventilatory method.

PubMed

Alberton, C L; Kanitz, A C; Pinto, S S; Antunes, A H; Finatto, P; Cadore, E L; Kruel, L F M

2013-08-01

The aim of this study was to compare the cardiorespiratory variables corresponding to the anaerobic threshold (AT) between different water-based exercises using two methods of determining the AT, the heart rate deflection point and ventilatory method, and to correlate the variables in both methods. Twenty young women performed three exercise sessions in the water. Maximal tests were performed in the water-based exercises stationary running, frontal kick and cross country skiing. The protocol started at a rate of 80 cycles per minute (cycle.min-1) for 2 min with subsequent increments of 10 cycle.min-1 every minute until exhaustion, with measurements of heart rate, oxygen uptake and ventilation throughout test. After, the two methods were used to determine the values of these variables corresponding to the AT for each of the exercises. Comparisons were made using two-way ANOVA for repeated measures with Bonferroni's post hoc test. To correlate the same variables determined by the two methods, the intra-class correlation coefficient test (ICC) was used. For all the variables, no significant differences were found between the methods of determining the AT and the three exercises. Moreover, the ICC values of each variable determined by the two methods were high and significant. The estimation of the heart rate deflection point can be used as a simple and practical method of determining the AT, which can be used when prescribing these exercises. In addition, these cardiorespiratory parameters may be determined performing the test with only one of the evaluated exercises, since there were no differences in the evaluated variables.

[Intravenous nitroglycerin infusion suppresses exercise-induced arrhythmia in patients with ischemic cardiopathy: indications for chronic treatment ].

PubMed

Bonetti, F; Margonato, A; Mailhac, A; Vicedomini, G; Cianflone, D; Scarpazza, P; Chierchia, S L

1990-05-01

In patients with ischemic heart disease and arrhythmias, selection of antiarrhythmic treatment is often difficult as it is hard to separate "primary" from ischemic arrhythmias. We studied 20 patients with ischemic heart disease, who developed ventricular arrhythmias consistently during exercise test. Exercise test was performed twice during infusion of placebo and then during intravenous administration of nitroglycerin, titrated to reduce systolic blood pressure by 10 mmHg. Exercise duration was 7.8 +/- 1.7 and 7.9 +/- 1.5 min, in the 2 placebo tests (NS). Angina developed in 5 patients and ischemic ST changes in 10. With nitroglycerin exercise duration increased to 8.4 +/- 20 min (p less than 0.05), diagnostic ST segment depression was observed in 2 patients and only 1 had angina. In all 20 patients, ventricular arrhythmias were consistently present during both tests on placebo, that were markedly reduced by nitroglycerin. In fact, ventricular ectopic beats were 455 (mean 35.8 +/- 16.8) and 418 (mean 34.4 +/- 11.1) in the 2 exercise tests with placebo, and 11 during nitroglycerin infusion (mean 0.6 +/- 0.1; p less than 0.001). Couplets were 28 and 29 during placebo (NS) and 0 during nitroglycerin (p less than 0.001). Ventricular tachycardia was present in 6 and 8 patients during placebo but in none during nitroglycerin (p less than 0.001). Reduction of exercise-induced arrhythmias was maintained during chronic treatment with oral vasodilators. Prevention of exercise-related arrhythmias by nitroglycerin infusion appears a good indicator of their ischemic origin and may provide valuable information for long-term profilaxis with oral vasodilators, then avoiding the use of antiarrhythmic agents and their potential side effects.

Influence of running stride frequency in heart rate variability analysis during treadmill exercise testing.

PubMed

Bailón, Raquel; Garatachea, Nuria; de la Iglesia, Ignacio; Casajús, Jose Antonio; Laguna, Pablo

2013-07-01

The analysis and interpretation of heart rate variability (HRV) during exercise is challenging not only because of the nonstationary nature of exercise, the time-varying mean heart rate, and the fact that respiratory frequency exceeds 0.4 Hz, but there are also other factors, such as the component centered at the pedaling frequency observed in maximal cycling tests, which may confuse the interpretation of HRV analysis. The objectives of this study are to test the hypothesis that a component centered at the running stride frequency (SF) appears in the HRV of subjects during maximal treadmill exercise testing, and to study its influence in the interpretation of the low-frequency (LF) and high-frequency (HF) components of HRV during exercise. The HRV of 23 subjects during maximal treadmill exercise testing is analyzed. The instantaneous power of different HRV components is computed from the smoothed pseudo-Wigner-Ville distribution of the modulating signal assumed to carry information from the autonomic nervous system, which is estimated based on the time-varying integral pulse frequency modulation model. Besides the LF and HF components, the appearance is revealed of a component centered at the running SF as well as its aliases. The power associated with the SF component and its aliases represents 22±7% (median±median absolute deviation) of the total HRV power in all the subjects. Normalized LF power decreases as the exercise intensity increases, while normalized HF power increases. The power associated with the SF does not change significantly with exercise intensity. Consideration of the running SF component and its aliases is very important in HRV analysis since stride frequency aliases may overlap with LF and HF components.

Aerobic exercise deconditioning and countermeasures during bed rest.

PubMed

Lee, Stuart M C; Moore, Alan D; Everett, Meghan E; Stenger, Michael B; Platts, Steven H

2010-01-01

Bed rest is a well-accepted model for spaceflight in which the physiologic adaptations, particularly in the cardiovascular system, are studied and potential countermeasures can be tested. Bed rest without countermeasures results in reduced aerobic capacity and altered submaximal exercise responses. Aerobic endurance and factors which may impact prolonged exercise, however, have not been well studied. The initial loss of aerobic capacity is rapid, occurring in parallel with the loss of plasma volume. Thereafter, the reduction in maximal aerobic capacity proceeds more slowly and is influenced by central and peripheral adaptation. Exercise capacity can be maintained during bed rest and may be improved during recovery with appropriate countermeasures. Plasma volume restoration, resistive exercise, orthostatic stress, aerobic exercise, and aerobic exercise plus orthostatic stress all have been tested with varying levels of success. However, the optimal combination of elements-exercise modality, intensity, duration, muscle groups exercised and frequency of aerobic exercise, orthostatic stress, and supplementary resistive or anaerobic exercise training-has not been systematically evaluated. Currently, frequent (at least 3 days per week) bouts of intense exercise (interval-style and near maximal) with orthostatic stress appears to be the most efficacious method to protect aerobic capacity during bed rest. Further refinement of protocols and countermeasure hardware may be necessary to insure the success of countermeasures in the unique environment of space.