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Sample records for cardiovascular responses produced

  1. Cardiovascular responses produced by central injection of hydrogen peroxide in conscious rats.

    PubMed

    Máximo Cardoso, Leonardo; de Almeida Colombari, Débora Simões; Vanderlei Menani, José; Alves Chianca, Deoclécio; Colombari, Eduardo

    2006-12-11

    Reactive oxygen species (ROS) have been shown to modulate neuronal synaptic transmission and may play a role on the autonomic control of the cardiovascular system. In this study we investigated the effects produced by hydrogen peroxide (H(2)O(2)) injected alone or combined with the anti-oxidant agent N-acetil-l-cysteine (NAC) or catalase into the fourth brain ventricle (4th V) on mean arterial pressure and heart rate of conscious rats. Moreover the involvement of the autonomic nervous system on the cardiovascular responses to H(2)O(2) into the 4th V was also investigated. Male Holtzman rats (280-320 g) with a stainless steel cannula implanted into the 4th V and polyethylene cannulas inserted into the femoral artery and vein were used. Injections of H(2)O(2) (0.5, 1.0 and 1.5 micromol/0.2 microL, n=6) into the 4th V produced transient (for 10 min) dose-dependent pressor responses. The 1.0 and 1.5 micromol doses of H(2)O(2) also produced a long lasting bradycardia (at least 24 h with the high dose of H(2)O(2)). Prior injection of N-acetyl-l-cysteine (250 nmol/1 microL/rat) into the 4th V blockade the pressor response and attenuated the bradycardic response to H(2)O(2) (1 micromol/0.5 microL/rat, n=7) into the 4th V. Intravenous (i.v.) atropine methyl bromide (1.0 mg/kg, n=11) abolished the bradycardia but did not affect the pressor response to H(2)O(2). Prazosin hydrochloride (1.0 mg/kg, n=6) i.v. abolished the pressor response but did not affect the bradycardia. The increase in the catalase activity (500 UEA/1 microL/rat injected into the 4th V) also abolished both, pressor and bradycardic responses to H(2)O(2). The results suggest that increased ROS availability into 4th V simultaneously activate sympathetic and parasympathetic outflow inducing pressor and bradycardic responses. PMID:17113926

  2. AV3V lesions attenuate the cardiovascular responses produced by blood-borne excitatory amino acid analogs

    NASA Technical Reports Server (NTRS)

    Whalen, E. J.; Beltz, T. G.; Lewis, S. J.; Johnson, A. K.

    1999-01-01

    Systemic injections of the excitatory amino acid (EAA) analogs, kainic acid (KA) and N-methyl-D-aspartate (NMDA), produce a pressor response in conscious rats that is caused by a centrally mediated activation of sympathetic drive and the release of arginine vasopressin (AVP). This study tested the hypothesis that the tissue surrounding the anteroventral part of the third ventricle (AV3V) plays a role in the expression of the pressor responses produced by systemically injected EAA analogs. Specifically, we examined whether prior electrolytic ablation of the AV3V region would affect the pressor responses to KA and NMDA (1 mg/kg iv) in conscious rats. The KA-induced pressor response was smaller in AV3V-lesioned than in sham-lesioned rats (11 +/- 2 vs. 29 +/- 2 mmHg; P < 0.05). After ganglion blockade, KA produced a pressor response in sham-lesioned but not AV3V-lesioned rats (+27 +/- 3 vs. +1 +/- 2 mmHg; P < 0.05). The KA-induced pressor response in ganglion-blocked sham-lesioned rats was abolished by a vasopressin V1-receptor antagonist. Similar results were obtained with NMDA. The pressor response to AVP (10 ng/kg iv) was slightly smaller in AV3V-lesioned than in sham-lesioned ganglion-blocked rats (45 +/- 3 vs. 57 +/- 4 mmHg; P < 0.05). This study demonstrates that the pressor responses to systemically injected EAA analogs are smaller in AV3V-lesioned rats. The EAA analogs may produce pressor responses by stimulation of EAA receptors in the AV3V region, or the AV3V region may play an important role in the expression of these responses.

  3. Cardiovascular responses to spaceflight

    NASA Technical Reports Server (NTRS)

    Nicogossian, A.; Pool, S. L.; Rambaut, P. C.

    1983-01-01

    The cardiovascular system's adaptive changes during and after spaceflight are discussed. Cephalic fluid shifts are demonstrated by photographs along with calf girth and leg volume changes. Inflight measurements show an increase in average resting heart rate and systolic blood pressure, and a sympathetic-parasympathetic neural imbalance. Postflight findings include a small but reversible decrease in the left ventricular muscle mass. Since 1980, NASA's research has emphasized cardiovascular deconditioning and countermeasures: hemodynamic changes, endocrine and neurohumoral aspects, etiologic factors, and lower body negative pressure devices. Though human beings acclimate to the space environment, questions concerning the immediate and long-term aspects of spaceflight need to be answered for adequate planning of extended space missions.

  4. Cardiovascular response to thermoregulatory challenges.

    PubMed

    Liu, Cuiqing; Yavar, Zubin; Sun, Qinghua

    2015-12-01

    A growing number of extreme climate events are occurring in the setting of ongoing climate change, with an increase in both the intensity and frequency. It has been shown that ambient temperature challenges have a direct and highly varied impact on cardiovascular health. With a rapidly growing amount of literature on this issue, we aim to review the recent publications regarding the impact of cold and heat on human populations with regard to cardiovascular disease (CVD) mortality/morbidity while also examining lag effects, vulnerable subgroups, and relevant mechanisms. Although the relative risk of morbidity/mortality associated with extreme temperature varied greatly across different studies, both cold and hot temperatures were associated with a positive mean excess of cardiovascular deaths or hospital admissions. Cause-specific study of CVD morbidity/mortality indicated that the sensitivity to temperature was disease-specific, with different patterns for acute and chronic ischemic heart disease. Vulnerability to temperature-related mortality was associated with some characteristics of the populations, including sex, age, location, socioeconomic condition, and comorbidities such as cardiac diseases, kidney diseases, diabetes, and hypertension. Temperature-induced damage is thought to be related to enhanced sympathetic reactivity followed by activation of the sympathetic nervous system, renin-angiotensin system, as well as dehydration and a systemic inflammatory response. Future research should focus on multidisciplinary adaptation strategies that incorporate epidemiology, climatology, indoor/building environments, energy usage, labor legislative perfection, and human thermal comfort models. Studies on the underlying mechanism by which temperature challenge induces pathophysiological response and CVD await profound and lasting investigation. PMID:26432837

  5. Cardiovascular response to punching tempo.

    PubMed

    Kravitz, Len; Greene, Larry; Burkett, Zachary; Wongsathikun, Jataporn

    2003-02-01

    Eighteen trained volunteers (12 men and 6 women: age = 22.0 +/- 2.8 years, height = 170.79 +/- 7.67 cm, weight = 71.54 +/- 12.63 kg) participated in 2-minute, randomized fitness boxing trials, wearing 0.34-kg punching gloves, at various tempos (60, 72, 84, 96, 108, and 120 b.min(-1)). During each trial, oxygen uptake (VO(2)), heart rate (HR), and ventilation (VE) were measured continuously. A rating of perceived exertion (RPE) was attained at the conclusion of each trial. Subjects were able to attain VO(2) values ranging from 26.83 to 29.75 ml.kg(-1).min(-1), which correspond to 67.7-72.5% of VO(2)max. The HR responses yielded results ranging from 167.4 to 182.2 b.min(-1), or 85 to 93% of HRmax. No significant difference (p > 0.05) was seen with VO(2) between trials, although a significant difference (p < 0.05) was observed with HR, VE, and RPE. It appears that boxing speed is associated with increased VE, HR response, and perceived effort but not with VO(2). Energy expenditure values ranged from 9.8 to 11.2 kcal.min(-1) for the boxing trials. These results suggest that fitness boxing programs compare favorably with other exercise modalities in cardiovascular response and caloric expenditure. PMID:12580664

  6. Cardiovascular responses of snakes to hypergravity

    NASA Technical Reports Server (NTRS)

    Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Rosenberg, H. I.

    1997-01-01

    Snakes have provided useful vertebrate models for understanding circulatory adaptation to gravity, attributable to their elongate body shape and evolutionary diversificaton in terms of ecology and behavior. Recently we have studied cardiovascular responses of snakes to hypergravic acceleration forces produced acutely in the head-to-tail direction (+Gz) on a short-arm centrifuge. Snakes were held in a nearly straight position within a horizontal plastic tube and subjected to a linear force gradient during acceleration. Carotid blood flow provided an integrated measure of cardiovascular performance. Thus, cardiovascular tolerance of snakes to stepwise increments of Gz was measured as the caudal Gz force at which carotid blood flow ceased. Tolerance to increasing Gz varies according to adaptive evolutionary history inferred from the ecology and behavior of species. With respect to data for six species we investigated, multiple regression analysis demonstrates that Gz tolerance correlates with gravitational habitat, independently of body length. Relative to aquatic and non-climbing species, carotid blood flow is better maintained in arboreal or scansorial species, which tolerate hypergravic forces of +2 to +3.5 Gz. Additionally, semi-arboreal rat snakes (Elaphe obsoleta) exhibit plasticity of responses to long-term, intermittent +1.5 Gz stress. Compared to non-acclimated controls, acclimated snakes show greater increases of heart rate during head-up tilt or acceleration, greater sensitivity of arterial pressure to circulating catecholamines, higher blood levels of prostaglandin ratios favorable to maintenance of arterial blood pressure, and medial hypertrophy in major arteries and veins. As in other vertebrates, Gz tolerance of snakes is enhanced by acclimation, high arterial pressure, comparatively large blood volume, and body movements. Vascular studies of snakes suggest the importance to acclimation of local responses involving vascular tissue, in addition to

  7. Cardiovascular responses to hypogravic environments

    NASA Technical Reports Server (NTRS)

    Sandler, H.

    1983-01-01

    The cardiovascular deconditioning observed during and after space flight is characterized in a review of human space and simulation studies and animal simulations. The various simulation techniques (horizontal bed rest, head-down tilt, and water immersion in man, and immobilization of animals) are examined, and sample results are presented in graphs. Countermeasures such as exercise regimens, fluid replacement, drugs, venous pooling, G-suits, oscillating beds, electrostimulation of muscles, lower-body negative pressure, body-surface cooling, and hypoxia are reviewed and found to be generally ineffective or unreliable. The need for future space experimentation in both humans and animals is indicated.

  8. Role of the anterior region of the third ventricle in the cardiovascular responses produced by systemic injection of a nitric oxide synthase inhibitor

    NASA Technical Reports Server (NTRS)

    Lewis, S. J.; Whalen, E. J.; Beltz, T. G.; Johnson, A. K.

    1999-01-01

    This study examined whether a prior electrolytic lesion of the tissue surrounding the anteroventral third ventricle (AV3V) would affect the increase in mean arterial blood pressure (MAP) and the fall in heart rate (HR) produced by systemic injection of the nitric oxide synthesis (NOS) inhibitor, NG-nitro-L-arginine methyl ester (L-NAME; 25 micromol/kg, i.v.) in conscious rats. L-NAME produced a smaller increase in MAP in AV3V-lesion than in sham-lesion rats (+19+/-3 vs. +40+/-3 mmHg, respectively; P<0.05). In contrast, L-NAME produced similar falls in HR in the AV3V-lesion and sham-lesion rats (-103+/-15 vs. -97+/-8 bpm, respectively; P<0.05). These findings demonstrate that the L-NAME-induced pressor response is dependent upon the integrity of the AV3V region, whereas the L-NAME-induced bradycardia is not. Copyright 1999 Elsevier Science B. V.

  9. Human Cardiovascular Responses to Passive Heat Stress

    PubMed Central

    Crandall, Craig G.; Wilson, Thad E.

    2016-01-01

    Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur. PMID:25589263

  10. Human cardiovascular responses to passive heat stress.

    PubMed

    Crandall, Craig G; Wilson, Thad E

    2015-01-01

    Heat stress increases human morbidity and mortality compared to normothermic conditions. Many occupations, disease states, as well as stages of life are especially vulnerable to the stress imposed on the cardiovascular system during exposure to hot ambient conditions. This review focuses on the cardiovascular responses to heat stress that are necessary for heat dissipation. To accomplish this regulatory feat requires complex autonomic nervous system control of the heart and various vascular beds. For example, during heat stress cardiac output increases up to twofold, by increases in heart rate and an active maintenance of stroke volume via increases in inotropy in the presence of decreases in cardiac preload. Baroreflexes retain the ability to regulate blood pressure in many, but not all, heat stress conditions. Central hypovolemia is another cardiovascular challenge brought about by heat stress, which if added to a subsequent central volumetric stress, such as hemorrhage, can be problematic and potentially dangerous, as syncope and cardiovascular collapse may ensue. These combined stresses can compromise blood flow and oxygenation to important tissues such as the brain. It is notable that this compromised condition can occur at cardiac outputs that are adequate during normothermic conditions but are inadequate in heat because of the increased systemic vascular conductance associated with cutaneous vasodilation. Understanding the mechanisms within this complex regulatory system will allow for the development of treatment recommendations and countermeasures to reduce risks during the ever-increasing frequency of severe heat events that are predicted to occur. PMID:25589263

  11. The cardiovascular response to the AGS

    NASA Technical Reports Server (NTRS)

    Cardus, David; Mctaggart, Wesley G.

    1993-01-01

    This paper reports the preliminary results of experiments on human subjects conducted to study the cardiovascular response to various g-levels and exposure times using an artificial gravity simulator (AGS). The AGS is a short arm centrifuge consisting of a turntable, a traction system, a platform and four beds. Data collection hardware is part of the communication system. The AGS provides a steep acceleration gradient in subjects in the supine position.

  12. Airway reflexes, autonomic function, and cardiovascular responses.

    PubMed Central

    Widdicombe, J; Lee, L Y

    2001-01-01

    In this article, we review the cardiovascular responses to the inhalation of irritants and pollutants. Many sensory receptors in the respiratory system, from nose to alveoli, respond to these irritants and set up powerful reflex changes, including those in the cardiovascular system. Systemic hypotension or hypertension, pulmonary hypertension, bradycardia, tachycardia, and dysrhythmias have all been described previously. Most of the experiments have been acute and have been performed on anesthetized experimental animals. Experiments on humans suggest we have similar sensory systems and reflex responses. However, we must use caution when applying the animal results to humans. Most animal experiments, unlike those with humans, have been performed using general anesthesia, with irritants administered in high concentrations, and often to a restricted part of the respiratory tract. Species differences in the response to irritants are well established. We must be even more careful when applying the results of acute experiments in animals to the pathophysiologic changes observed in prolonged exposure to environmental pollution in humans. PMID:11544167

  13. Modeling of Cardiovascular Response to Weightlessness

    NASA Technical Reports Server (NTRS)

    Sharp, M. Keith

    1999-01-01

    It was the hypothesis of this Project that the Simple lack of hydrostatic pressure in microgravity generates several purely physical reactions that underlie and may explain, in part, the cardiovascular response to weightlessness. For instance, hydrostatic pressure within the ventricles of the heart may improve cardiac performance by promoting expansion of ventricular volume during diastole. The lack of hydrostatic pressure in microgravity might, therefore, reduce diastolic filling and cardiac performance. The change in transmural pressure is possible due to the difference in hydrostatic pressure gradients between the blood inside the ventricle and the lung tissue surrounding the ventricle due to their different densities. On the other hand, hydrostatic pressure within the vasculature may reduce cardiac inlet pressures because of the typical location of the heart above the hydrostatic indifference level (the level at which pressure remains constant throughout changes in gravity). Additional physical responses of the body to changing gravitational conditions may influence cardiovascular performance. For instance, fluid shifts from the lower body to the thorax in microgravity may serve to increase central venous pressure (CVP) and boost cardiac output (CO). The concurrent release of gravitational force on the rib cage may tend to increase chest girth and decrease pedcardial pressure, augmenting ventricular filling. The lack of gravity on pulmonary tissue may allow an upward shifting of lung mass, causing a further decrease in pericardial pressure and increased CO. Additional effects include diuresis early in the flight, interstitial fluid shifts, gradual spinal extension and movement of abdominal mass, and redistribution of circulatory impedance because of venous distention in the upper body and the collapse of veins in the lower body. In this project, the cardiovascular responses to changes in intraventricular hydrostatic pressure, in intravascular hydrostatic

  14. Cardiovascular responses to a hot tub bath.

    PubMed

    Boone, T; Westendorf, T; Ayres, P

    1999-06-01

    This study was conducted to determine the cardiovascular effects of 15 minutes of hot tub immersion at 39 degrees C. Five college-age subjects (4 males and 1 female) volunteered to participate in this study. Assessments were made while sitting first in a chair for 5 minutes and then in the hot tub for 15 minutes. Oxygen consumption (VO2) and cardiac output (Q) measurements were made using a Medical Graphics CPX/D metabolic analyzer. Cardiac output was determined at minute 15 using the indirect CO2 rebreathing procedure. The data were analyzed using the analysis of variance with repeated measures, which indicated that at minute 15, heart rate (HR) and Q were increased, which increased VO2. The increase in Q was due to the heart rate (HR) response and the decrease in systemic vascular resistance (SVR). Mean arterial pressure (MAP) and systolic blood pressure (SBP) were decreased while double product (DP) was increased. There were no changes in stroke volume (SV) or arteriovenous oxygen difference (a-vO2 diff). These findings indicate that the HR and Q responses are necessary to the increase in metabolism (VO2). Hot tube use within these time and temperature constraints should reduce concern over hot tub safety in college-age subjects. PMID:10381255

  15. Cardiovascular Responses of Snakes to Gravitational Gradients

    NASA Technical Reports Server (NTRS)

    Hsieh, Shi-Tong T.; Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.; Holton, Emily M. (Technical Monitor)

    1998-01-01

    Snakes are useful vertebrates for studies of gravitational adaptation, owing to their elongate body and behavioral diversification. Scansorial species have evolved specializations for regulating hemodynamics during exposure to gravitational stress, whereas, such adaptations are less well developed in aquatic and non-climbing species. We examined responses of the amphibious snake,\\italicize (Nerodia rhombifera), to increments of Gz (head-to-tail) acceleration force on both a short- and long-arm centrifuge (1.5 vs. 3.7 m radius, from the hub to tail end of snake). We recorded heart rate, dorsal aortic pressure, and carotid arterial blood flow during stepwise 0.25 G increments of Gz force (referenced at the tail) in conscious animals. The Benz tolerance of a snake was determined as the Gz level at which carotid blood flow ceased and was found to be significantly greater at the short- than long-arm centrifuge radius (1.57 Gz vs. 2.0 Gz, respectively; P=0.016). A similar pattern of response was demonstrated in semi-arboreal rat snakes,\\italicize{Elaphe obsoleta}, which are generally more tolerant of Gz force (2.6 Gz at 1.5m radius) than are water snakes. The tolerance differences of the two species reflected cardiovascular responses, which differed quantitatively but not qualitatively: heart rates increased while arterial pressure and blood flow decreased in response to increasing levels of Gz. Thus, in both species of snakes, a reduced gradient of Gz force (associated with greater centrifuge radius) significantly decreases the Gz level that can be tolerated.

  16. Gravitational effects on human cardiovascular responses to isometric muscle contractions

    NASA Astrophysics Data System (ADS)

    Bonde-Petersen, Flemmig; Suzuki, Yoji; Sadamoto, Tomoko

    Isometric exercise induces profound cardiovascular adaptations increasing mean arterial pressure and heart rate. We investigated effects of simulated +Gz and -Gz respectively on the central and peripheral cardiovascular system. Sustained handgrip exercise was performed at 40% of maximum for 2 minutes in five subjects. This maneuver increased mean arterial pressure by 40-45 mm Hg both during head out water immersion which simulates weightlessness, as well as bedrest during -25, 0, and +25 degrees tilt from the horizontal. Lower body negative pressure (-60 mm Hg for 10 min) attenuated the response to handgrip exercise to 30 mm Hg. It also increased the heart rate minimally by about 20 beats per minute while the water immersion, as well as head up, head down and horizontal bedrest showed increments of about 50 beats per min. It was concluded that the response to isometric contraction is mediated through the high pressure baroreceptors, because similar responses were seen during stresses producing a wide variation in central venous pressure. During lower body negative pressure the increased sympathetic nervous activity itself increased resting heart rate and mean arterial pressure. The responses to static exercise were, therefore, weaker.

  17. Maturation of the angiotensin II cardiovascular response in the embryonic White Leghorn chicken (Gallus gallus)

    PubMed Central

    Jonker, Sonnet S.; Hicks, James W.; Thornburg, Kent L.

    2010-01-01

    Angiotensin II (Ang II) is an important regulator of cardiovascular function in adult vertebrates. Although its role in regulating the adult system has been extensively investigated, the cardiovascular response to Ang II in embryonic vertebrates is relatively unknown. We investigated the potential of Ang II as a regulator of cardiovascular function in embryonic chickens, which lack central nervous system control of cardiovascular function throughout the majority of incubation. The cardiovascular response to Ang II in embryonic chickens was investigated over the final 50% of their development. Ang II produced a dose-dependent increase in arterial pressure on each day of development studied, and the response increased in intensity as development progressed. The Ang II type-1 receptor nonspecific competitive peptide antagonist [Sar1 ile8] Ang II blocked the cardiovascular response to subsequent injections of Ang II on day 21 only. The embryonic pressure response to Ang II (hypertension only) differed from that of adult chickens, in which initial hypotension is followed by hypertension. The constant level of gene expression for the Ang II receptor, in conjunction with an increasing pressure response to the peptide, suggests that two Ang II receptor subtypes are present during chicken development. Collectively, the data indicate that Ang II plays an important role in the cardiovascular development of chickens; however, its role in maintaining basal function requires further study. PMID:20495810

  18. Cardiovascular responses during hypoventilation at exercise.

    PubMed

    Woorons, X; Bourdillon, N; Lamberto, C; Vandewalle, H; Richalet, J-P; Mollard, P; Pichon, A

    2011-06-01

    This study aimed to determine the cardiovascular responses during a prolonged exercise with voluntary hypoventilation (VH). 7 men performed 3 series of 5-min exercise at 65% of normoxic maximal O (2) uptake under 3 conditions: (1) normal breathing (NB) in normoxia (NB (0.21)), (2) VH in normoxia (VH (0.21)), (3) NB in hypoxia (NB (0.157), inspired oxygen fraction=0.157). In both VH (0.21) and NB (0.157), there was a similar drop in arterial oxygen saturation and arterial O (2) content (CaO (2)) which were lower than in NB (0.21). Heart rate (HR), stroke volume, and cardiac output (-) were higher in VH (0.21) than in NB (0.21) during most parts of exercise whereas there was no difference between NB (0.157) and VH (0.21) or NB (0.21). HR variability analysis suggested an increased sympathetic modulation in VH (0.21) only. O (2) transport and oxygen uptake were generally not different between interventions. Mixed venous O (2) content (C-O (2)) was lower in NB (0.157) than in both VH (0.21) and NB (0.21) and not different between the latter. CaO (2)-C-O (2) was not different between NB (0.157) and NB (0.21) but lower in VH (0.21). This study shows that a prolonged exercise with VH leads to a greater cardiac activity, independent from the hypoxic effect. The greater - in VH compared to normal breathing seems to be the main factor for compensating the drop of arterial oxygen content. PMID:21563023

  19. Simultaneous cerebrovascular and cardiovascular responses during presyncope

    NASA Technical Reports Server (NTRS)

    Bondar, R. L.; Kassam, M. S.; Stein, F.; Dunphy, P. T.; Fortney, S.; Riedesel, M. L.

    1995-01-01

    BACKGROUND AND PURPOSE: Presyncope, characterized by symptoms and signs indicative of imminent syncope, can be aborted in many situations before loss of consciousness occurs. The plasticity of cerebral autoregulation in healthy humans and its behavior during this syncopal prodrome are unclear, although systemic hemodynamic instability has been suggested as a key factor in the precipitation of syncope. Using lower body negative pressure (LBNP) to simulate central hypovolemia, we previously observed falling mean flow velocities (MFVs) with maintained mean arterial blood pressure (MABP). These findings, and recent reports suggesting increased vascular tone within the cerebral vasculature at presyncope, cannot be explained by the classic static cerebral autoregulation curve; neither can they be totally explained by a recent suggestion of a rightward shift in this curve. METHODS: Four male and five female healthy volunteers were exposed to presyncopal LBNP to evaluate their cerebrovascular and cardiovascular responses by use of continuous acquisition of MFV from the right middle cerebral artery with transcranial Doppler sonography, MABP (Finapres), and heart rate (ECG). RESULTS: At presyncope, MFV dropped on average by 27.3 +/- 14% of its baseline value (P < .05), while MABP remained at 2.0 +/- 27% above its baseline level. Estimated cerebrovascular resistance increased during LBNP. The percentage change from baseline to presyncope in MFV and MABP revealed consistent decreases in MFV before MABP. CONCLUSIONS: Increased estimated cerebrovascular resistance, falling MFV, and constant MABP are evidence of an increase in cerebral vascular tone with falling flow, suggesting a downward shift in the cerebral autoregulation curve. Cerebral vessels may have a differential sensitivity to sympathetic drive or more than one type of sympathetic innervation. Future work to induce dynamic changes in MABP during LBNP may help in assessing the plasticity of the cerebral autoregulation

  20. Gender-based differences in the cardiovascular response to standing

    NASA Technical Reports Server (NTRS)

    Gotshall, Robert W.; Tsai, Pai-Feng; Frey, Mary A. B.

    1991-01-01

    The cardiovascular responses of men and women to the stand test were compared by measuring respective values for heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance during a 5-min supine and a 5-min standing test in ten subjects of each gender. It was found that, while the male and female subjects had similar heart rate values, all other responses exhibited greater changes in men than in women. While differences in the height of the subjects did not account for differences in cardiovascular responses, no mechanism responsible for these differences could be identified.

  1. Computational modelling and evaluation of cardiovascular response under pulsatile impeller pump support

    PubMed Central

    Shi, Yubing; Brown, Alistair G.; Lawford, Patricia V.; Arndt, Andreas; Nuesser, Peter; Hose, D. Rodney

    2011-01-01

    This study presents a numerical simulation of cardiovascular response in the heart failure condition under the support of a Berlin Heart INCOR impeller pump-type ventricular assist device (VAD). The model is implemented using the CellML modelling language. To investigate the potential of using the Berlin Heart INCOR impeller pump to produce physiologically meaningful arterial pulse pressure within the various physiological constraints, a series of VAD-assisted cardiovascular cases are studied, in which the pulsation ratio and the phase shift of the VAD motion profile are systematically changed to observe the cardiovascular responses in each of the studied cases. An optimization process is proposed, including the introduction of a cost function to balance the importance of the characteristic cardiovascular variables. Based on this cost function it is found that a pulsation ratio of 0.35 combined with a phase shift of 200° produces the optimal cardiovascular response, giving rise to a maximal arterial pulse pressure of 12.6 mm Hg without inducing regurgitant pump flow while keeping other characteristic cardiovascular variables within appropriate physiological ranges. PMID:22670203

  2. Computer model of cardiovascular control system responses to exercise

    NASA Technical Reports Server (NTRS)

    Croston, R. C.; Rummel, J. A.; Kay, F. J.

    1973-01-01

    Approaches of systems analysis and mathematical modeling together with computer simulation techniques are applied to the cardiovascular system in order to simulate dynamic responses of the system to a range of exercise work loads. A block diagram of the circulatory model is presented, taking into account arterial segments, venous segments, arterio-venous circulation branches, and the heart. A cardiovascular control system model is also discussed together with model test results.

  3. Gender-Related Differences in Cardiovascular Responses to Orthostatic Stress

    NASA Technical Reports Server (NTRS)

    Fritsch-Yelle, Janice M.; DAunno, Dominick S.; Waters, Wendy W.; Freeman-Perez, Sondra

    1999-01-01

    There is evidence that men and women have different cardiovascular responses to standing, and that women are more susceptible to orthostatic hypotension than men. The present study seeks to determine if decreased orthostatic tolerance in women is caused by diminished vasoconstrictive responses.

  4. Early growth response-1 in the pathogenesis of cardiovascular disease.

    PubMed

    Khachigian, Levon M

    2016-07-01

    This article reviews the regulatory roles of the immediate-early gene product and prototypic zinc finger transcription factor, early growth response-1 in models of cardiovascular pathobiology, focusing on insights using microRNA, DNAzymes, small hairpin RNA, small interfering RNA, oligonucleotide decoy strategies and mice deficient in early growth response-1. PMID:27251707

  5. Gender-based differences in the cardiovascular response to standing.

    PubMed

    Gotshall, R W; Tsai, P F; Frey, M A

    1991-09-01

    Reduced tolerance to orthostatic stress is a recognized consequence of spaceflight. Both men and women serve as astronauts and are staying longer in space. While there are recognized cardiovascular differences in baseline function based on gender, little is known about any gender-based differences in cardiovascular responses to orthostatic stress. The purpose of this study was to compare the cardiovascular responses of men and women to the stand test. The subjects were 10 men and 10 women, 20-30 years of age. Heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance were monitored during 5 min supine and 5 min standing. Men responded similarly in heart rate (39 vs. 35%); but had significantly greater decreases in stroke volume (-53 vs. -40%), cardiac output (-36 vs. -21%), and pulse pressure (-19 vs. -12%); and greater increases in blood pressure (11 vs. 6%) and total peripheral resistance (77 vs. 34%) than did the women. Men and women demonstrated fundamental differences in cardiovascular responses during standing. Differences in the height of the subjects did not account for these differing cardiovascular responses. The mechanisms for these differences are not yet clear. Men and women should be studied as separate groups until these differences are understood. PMID:1930074

  6. Pain tests provoke modality-specific cardiovascular responses in awake, unrestrained rats

    PubMed Central

    Rigaud, Marcel; Gemes, Geza; Abram, Stephen E.; Dean, Caron; Hopp, Francis A.; Stucky, Cheryl L.; Eastwood, Daniel; Tarima, Sergey; Seagard, Jeanne; Hogan, Quinn H.

    2010-01-01

    Nociception modulates heart rate (HR) and mean arterial pressure (MAP), suggesting their use as indicators of pain in animals. We explored this with telemetric recording in unrestrained control and neuropathic (spinal nerve ligation) rats. Plantar stimulation was performed emulating techniques commonly used to measure pain, specifically brush stroke, von Frey fiber application, noxious pin stimulation, acetone for cooling, and radiant heating, while recording MAP, HR, and specific evoked somatomotor behaviors (none; simple withdrawal; or sustained lifting, shaking and grooming representing hyperalgesia). Pin produced elevations in both HR and MAP, and greater responses accompanied hyperalgesia behavior compared to simple withdrawal. Von Frey stimulation depressed MAP, and increased HR only when stimulation produced hyperalgesia behavior, suggesting that minimal nociception occurs without this behavior. Brush increased MAP even when no movement was evoked. Cold elevated both HR and MAP whether or not there was withdrawal, but MAP increased more when withdrawal was triggered. Heating consistently depressed HR and MAP, independent of behavior. Other than a greater HR response to pin in animals made hyperalgesic by injury, cardiovascular events evoked by stimulation did not differ between control and neuropathic animals. We conclude that a) thermoregulation rather than pain may dominate responses to heat and cooling stimuli; b) brush and cooling stimuli may be perceived and produce cardiovascular activation without nocifensive withdrawal; c) sensations that produce hyperalgesia behavior are accompanied by greater cardiovascular activation than those producing simple withdrawal; and d) von Frey stimulation lacks cardiovascular evidence of nociception except when hyperalgesia behavior is evoked. PMID:20943317

  7. Cardiovascular responses of women to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Frey, M. A. B.; Mathes, K. L.; Hoffler, G. W.

    1986-01-01

    The effects of lower body negative pressure (LBNP) on the cardiovascular response of 20 women between 23-43 years are evaluated. Calf circumference and cardiovascular data were recorded for women in the follicular and luteal phases of the menstrual cycle at -30, -40, and -50 mm Hg LBNP. The data reveal that the two menstrual phases did not cause differences in the way women respond to LBNP. It is observed that during LBNP calf circumference is enlarged; transthoracic impedance, and heart rate are increased; stroke volume, left ventricular ejection time, the Heather Index of contractility and systolic pressure, and cardiac output are reduced; and total peripheral resistance is elevated. The experimental data are compared to Montgomery et al. (1979). It is noted that the response of women to -50 mm Hg LBNP is similar to that of men; however, women adapt to stresses on the cardiovascular system with greater heart rate adjustments.

  8. Cardiovascular Response During Submaximal Underwater Treadmill Exercise in Stroke Patients

    PubMed Central

    Yoo, Jeehyun; Lim, Kil-Byung; Lee, Hong-Jae

    2014-01-01

    Objective To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients. Methods Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR. Results SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking. Conclusion Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation. PMID:25379492

  9. CARDIOVASCULAR RESPONSES TO ULTRAFINE CARBON PARTICLE EXPOSURES IN RATS

    EPA Science Inventory

    TD-02-042 (U. KODAVANTI) GPRA # 10108

    Cardiovascular Responses to Ultrafine Carbon Particle Exposures in Rats.
    V. Harder1, B. Lentner1, A. Ziesenis1, E. Karg1, L. Ruprecht1, U. Kodavanti2, A. Stampfl3, J. Heyder1, H. Schulz1
    GSF- Institute for Inhalation Biology1, I...

  10. Coupling of metabolism and cardiovascular response represents normal physiology.

    PubMed

    Steinberg, Helmut O

    2003-12-01

    In this issue of Clinical Science, Fugmann and co-workers demonstrate a highly integrated cardiovascular response to changes in plasma concentrations of glucose, triacylglycerols (triglycerides), fatty acids and insulin. Since the different substrates, alone and combined, evoked these changes, this response is likely to be a physiological one and directed towards minimizing the extent and duration of substrate elevations that could cause vascular dysfunction. PMID:12917009

  11. Cardiovascular Response Patterns to Sympathetic Stimulation by Central Hypovolemia

    PubMed Central

    Bronzwaer, Anne-Sophie G. T.; Verbree, Jasper; Stok, Wim J.; van Buchem, Mark A.; Daemen, Mat J. A. P.; van Osch, Matthias J. P.; van Lieshout, Johannes. J.

    2016-01-01

    In healthy subjects, variation in cardiovascular responses to sympathetic stimulation evoked by submaximal lower body negative pressure (LBNP) is considerable. This study addressed the question whether inter-subject variation in cardiovascular responses coincides with consistent and reproducible responses in an individual subject. In 10 healthy subjects (5 female, median age 22 years), continuous hemodynamic parameters (finger plethysmography; Nexfin, Edwards Lifesciences), and time-domain baroreflex sensitivity (BRS) were quantified during three consecutive 5-min runs of LBNP at −50 mmHg. The protocol was repeated after 1 week to establish intra-subject reproducibility. In response to LBNP, 5 subjects (3 females) showed a prominent increase in heart rate (HR; 54 ± 14%, p = 0.001) with no change in total peripheral resistance (TPR; p = 0.25) whereas the other 5 subjects (2 females) demonstrated a significant rise in TPR (7 ± 3%, p = 0.017) with a moderate increase in HR (21 ± 9%, p = 0.004). These different reflex responses coincided with differences in resting BRS (22 ± 8 vs. 11 ± 3 ms/mmHg, p = 0.049) and resting HR (57 ± 8 vs. 71 ± 12 bpm, p = 0.047) and were highly reproducible over time. In conclusion, we found distinct cardiovascular response patterns to sympathetic stimulation by LBNP in young healthy individuals. These patterns of preferential autonomic blood pressure control appeared related to resting cardiac BRS and HR and were consistent over time. PMID:27378944

  12. Cardiovascular responses of women to lower body negative pressure.

    PubMed

    Frey, M A; Mathes, K L; Hoffler, G W

    1986-06-01

    Lower body negative pressure (LBNP) has provided a method for studying cardiovascular responses in men while simulating a return to the stresses of 1-G following space flight. In this study, we have monitored responses of women to the stresses provided by LBNP. There were 20 women, 23-43 years, each tested in the follicular and luteal phases of the menstrual cycle. Variables were recorded during supine control; at -30, -40, -50 mm Hg LBNP; immediately after pressure release; and after 5 min recovery. There were no significant differences in response to LBNP between the two menstrual phases. During LBNP calf circumference was enlarged; transthoracic impedance was increased; stroke volume, left ventricular ejection time, the Heather Index of contractility and systolic pressure were reduced; total peripheral resistance was elevated; and cardiac output fell despite a rise in heart rate. Differences in cardiovascular variables between 0 mm Hg LBNP and -50 mm Hg LBNP were generally similar to reported differences between supine and standing. The responses of these women to LBNP were qualitatively similar to those reported for the Apollo astronauts and other male subjects. These women appeared to compensate with a greater heart rate response; however, the net cardiovascular compensation as determined from arterial pressure appears to be similar in men and women. PMID:3718376

  13. Cardiovascular response to dynamic aerobic exercise: a mathematical model.

    PubMed

    Magosso, E; Ursino, M

    2002-11-01

    An original mathematical model of the cardiovascular response to dynamic exercise is presented. It includes the pulsating heart, the pulmonary and systemic circulation, a separate description of the vascular bed in active tissues, the local metabolic vasodilation in these tissues and the mechanical effects of muscular contractions on venous return. Moreover, the model provides a description of the ventilatory response to exercise and various neural regulatory mechanisms working on cardiovascular parameters. These mechanisms embrace the so-called central command, the arterial baroreflex and the lung inflation reflex. All parameters in the model have been given in accordance with physiological data from the literature. In this work, the model has been used to simulate the steady-state value of the main cardiorespiratory quantities at different levels of aerobic exercise and the temporal pattern in the transient phase from rest to moderate exercise. Results suggest that, with suitable parameter values the model is able accurately to simulate the cardiorespiratory response in the overall range of aerobic exercise. This response is characterised by a moderate hypertension (10-30%) and by a conspicuous increase in systemic conductance (80-130%), heart rate (64-150%) and cardiac output (100-200%). The transient pattern exhibits three distinct phases (lasting approximately 5s, 15s and 2 min), that reflect the temporal heterogeneity of the mechanisms involved. The model may be useful to improve understanding of exercise physiology and as an educational tool to analyse the complexity of cardiovascular and respiratory regulation. PMID:12507317

  14. Role of arterial baroreceptors in mediating cardiovascular response to exercise

    NASA Technical Reports Server (NTRS)

    Mcritchie, R. J.; Vatner, S. F.; Patrick, T. A.; Braunwald, E.; Boettcher, D.; Heyndrickx, G. R.

    1976-01-01

    Experiments were conducted to define the role of the major arterial baroreceptors during moderately severe exercise by comparing the responses of untethered conscious dogs instrumented for the measurement of aortic pressure and cardiac output with those of dogs with total arterial baroreceptor denervation. The reflex heart rate responses to intravenous bolus doses of methoxamine were also examined in intact animals, both at rest and during exercise. Methoxamine is found to cause striking bradycardia at rest, but little bradycardia during exercise. Experimental findings suggest that the arterial baroreceptor reflex is normally inhibited during severe exercise and therefore plays little role in modulating the cardiovascular response to exercise.

  15. Autonomic and cardiovascular responses to chemoreflex stress in apnoea divers.

    PubMed

    Steinback, Craig D; Breskovic, Toni; Banic, Ivana; Dujic, Zeljko; Shoemaker, J Kevin

    2010-08-25

    Sleep apnoea, with repeated periods of hypoxia, results in cardiovascular morbidity and concomitant autonomic dysregulation. Trained apnoea divers also perform prolonged apnoeas accompanied by large lung volumes, large reductions in cardiac output and severe hypoxia and hypercapnia. We tested the hypothesis that apnoea training would be associated with decreased cardiovagal and sympathetic baroreflex gains and reduced respiratory modulation of muscle sympathetic nerve activity (MSNA; microneurography). Six trained divers and six controls were studied at rest and during asphyxic rebreathing. Despite an elevated resting heart rate (70+/-14 vs. 56+/-10 bpm; p=0.038), divers had a similar cardiovagal baroreflex gain (-1.22+/-0.47 beats/mmHg) as controls (-1.29+/-0.61; NS). Similarly, though MSNA burst frequency was slightly higher in divers at rest (16+/-4 bursts/min vs. 10+/-5 bursts/min, p=0.03) there was no difference in baseline burst incidence, sympathetic baroreflex gain (-3.8+/-2.1%/mmHg vs. -4.7+/-1.7%/mmHg) or respiratory modulation of MSNA between groups. Resting total peripheral resistance (11.9+/-2.6 vs. 12.3+/-2.2 mmHg/L/min) and pulse wave velocity (5.82+/-0.55 vs. 6.10+/-0.51 m/s) also were similar between divers and controls, respectively. Further, the sympathetic response to asphyxic rebreathing was not different between controls and divers (-1.70+/-1.07 vs. -1.74+/-0.84 a.u./% desaturation). Thus, these data suggest that, unlike patients with sleep apnoea, apnoea training in otherwise healthy individuals does not produce detectable autonomic dysregulation or maladaption. PMID:20627720

  16. Simulation of cardiovascular response to acceleration stress following weightless exposure

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Leonard, J. I.

    1983-01-01

    Physiological adjustments taking place during space flight tend to reduce the tolerance of the crew to headward (+Gz) acceleration experienced during the reentry phase of the flight. This reduced tolerance to acceleration stress apparently arises from an adaptation to the microgravity environment of space, including a decrease in the total circulating blood volume. Countermeasures such as anti-g garments have long been known to improve the tolerance to headward g-force, but their effectiveness in space flight has not been fully evaluated. The simulation study presented in this paper is concerned with the response of the cardiovascular system to g-stress following cardiovascular deconditioning, resulting from exposure to weightlessness, or any of its ground-based experimental analogs. The results serve to demonstrate the utility of mathematical modeling and computer simulation for studying the causes of orthostatic intolerance and the remedial measures to lessen it.

  17. Exaggerated Exercise Blood Pressure Response and Future Cardiovascular Disease.

    PubMed

    Tzemos, Nikolaos; Lim, Pitt O; Mackenzie, Isla S; MacDonald, Thomas M

    2015-11-01

    Exaggerated blood pressure (BP) response to exercise predicts future hypertension. However, there is considerable lack of understanding regarding the mechanism of how this abnormal response is generated, and how it relates to the future establishment of cardiovascular disease. The authors studied 82 healthy male volunteers without cardiovascular risk factors. The participants were categorized into two age-matched groups depending on their exercise systolic BP (ExSBP) rise after 3 minutes of exercise using a submaximal step test: exaggerated ExSBP group (hyper-responders [peak SBP ≥ 180 mm Hg]) and low ExSBP responder group (hypo-responders [peak SBP <180 mm Hg]). Forearm venous occlusion plethysmography and intra-arterial infusions of acetylcholine (ACh), N(G)-monomethyl-L-arginine (L-NMMA), sodium nitroprusside (SNP), and norepinephrine (NE) were used to assess vascular reactivity. Proximal aortic compliance was assessed with ultrasound, and neurohormonal blood sampling was performed at rest and during peak exercise. The hyper-responder group exhibited a significantly lower increase in forearm blood flow (FBF) with ACh compared with the hypo-responder group (ΔFBF 215% [14] vs 332.3% [28], mean [standard error of the mean]; P<.001), as well as decreased proximal aortic compliance. The vasoconstrictive response to L-NMMA was significantly impaired in the hyper-responder group in comparison to the hypo-responder group (ΔFBF -40.2% [1.6] vs -50.2% [2.6]; P<.05). In contrast, the vascular response to SNP and NE were comparable in both groups. Peak exercise plasma angiotensin II levels were significantly higher in the hyper-responder group (31 [1] vs 23 [2] pg/mL, P=.01). An exaggerated BP response to exercise is related to endothelial dysfunction, decreased proximal aortic compliance, and increased exercise-related neurohormonal activation, the constellation of which may explain future cardiovascular disease. PMID:26235814

  18. Cardiovascular sympathetic arousal in response to different mental stressors.

    PubMed

    Mestanik, M; Mestanikova, A; Visnovcova, Z; Calkovska, A; Tonhajzerova, I

    2016-01-01

    The altered regulation of autonomic response to mental stress can result in increased cardiovascular risk. The laboratory tests used to simulate the autonomic responses to real-life stressors do not necessarily induce generalized sympathetic activation; therefore, the assessment of regulatory outputs to different effector organs could be important. We aimed to study the cardiovascular sympathetic arousal in response to different mental stressors (Stroop test, mental arithmetic test) in 20 healthy students. The conceivable sympathetic vascular index - spectral power of low frequency band of systolic arterial pressure variability (LF-SAP) and novel potential cardio-sympathetic index - symbolic dynamics heart rate variability index 0V% were evaluated. The heart and vessels responded differently to mental stress - while Stroop test induced increase of both 0V% and LF-SAP indices suggesting complex sympathetic arousal, mental arithmetic test evoked only 0V% increase compared to baseline (p<0.01, p<0.001, p<0.01, respectively). Significantly greater reactivity of LF-SAP, 0V%, heart rate (HR) and mean arterial pressure (MAP) were found in response to Stroop test compared to mental arithmetic test potentially indicating the effect of different central processing (0V%, LF-SAP: p<0.001; HR, MAP: p<0.01). The different effectors' sympathetic responses to cognitive stressors could provide novel important information regarding potential pathomechanisms of stress-related diseases. PMID:26674281

  19. Cardiovascular responses to glucagon - Physiologic measurement by external recordings.

    NASA Technical Reports Server (NTRS)

    Byrne, M. J.; Pigott, V.; Spodick, D. H.

    1972-01-01

    Assessment by noninvasive polygraphic techniques of the cardiovascular responses of normal subjects to intravenous injections of glucagon and glucagon diluent. A blinding procedure which eliminated observer bias was used during the reading of tracings. Analysis of group results showed that glucagon provoked uniformly significant changes, including increase in heart rate, blood pressure, pressure-rate product, and ejection time index, and decrease in prejection period, mechanical and electromechanical systole, left ventricular ejection time, and the ratio PEP/LVET. The principal results correlated well with those of previous studies of the hemodynamic effects of glucagon.

  20. Role of central hydrogen sulfide on ventilatory and cardiovascular responses to hypoxia in spontaneous hypertensive rats.

    PubMed

    Sabino, João Paulo J; Traslaviña, Guillermo A Ariza; Branco, Luiz G S

    2016-09-01

    Central hydrogen sulfide (H2S) has been reported to act as a gaseous neuromodulator involved in the ventilatory and cardiovascular control of normotensive rats, whereas no information is available in spontaneously hypertensive rats (SHR). We recorded minute ventilation (VE), mean arterial pressure (MAP) and heart rate (HR) before and after blocking of enzyme Cystathionine β-synthase (CBS) producing H2S in neural tissue by microinjection of aminooxyacetate (inhibitor of CBS) into the fourth ventricle of Wistar normotensive rats (WNR) and SHR followed by 30min of normoxia (21% inspired O2) or hypoxia (10% inspired O2) exposure. Microinjection of AOA or saline (1μL) did not change VE, MAP and HR during normoxia in both WNR and SHR. In WNR, hypoxia caused an increase in VE, HR and a decrease in MAP and these responses were unaltered by AOA. In SHR, hypoxia produced a higher increase of VE, and decrease in MAP and HR when compared to WNR, and these responses were all blunted by AOA. In conclusion, endogenous H2S plays important modulatory roles on hypoxia-induced ventilatory and cardiovascular responses, inhibiting the cardiovascular and stimulating the respiratory systems in SHR. PMID:27238370

  1. Aging affects the cardiovascular responses to cold stress in humans

    PubMed Central

    Hess, Kari L.; Wilson, Thad E.; Sauder, Charity L.; Gao, Zhaohui; Ray, Chester A.

    2009-01-01

    Cardiovascular-related mortality peaks during cold winter months, particularly in older adults. Acute physiological responses, such as increases in blood pressure, in response to cold exposure may contribute to these associations. To determine whether the blood pressure-raising effect (pressor response) of non-internal body temperature-reducing cold stress is greater with age, we measured physiological responses to 20 min of superficial skin cooling, via water-perfused suit, in 12 younger [25 ± 1 (SE) yr old] and 12 older (65 ± 2 yr old) adults. We found that superficial skin cooling elicited an increase in blood pressure from resting levels (pressor response; P < 0.05) in younger and older adults. However, the magnitude of this pressor response (systolic and mean blood pressure) was more than twofold higher in older adults (P < 0.05 vs. younger adults). The magnitude of the pressor response was similar at peripheral (brachial) and central (estimated in the aorta) measurement sites. Regression analysis revealed that aortic pulse wave velocity, a measure of central arterial stiffness obtained before cooling, was the best predictor of the increased pressor response to superficial skin cooling in older adults, explaining ∼63% of its variability. These results indicate that there is a greater pressor response to non-internal body temperature-reducing cold stress with age in humans that may be mediated by increased levels of central arterial stiffness. PMID:19679742

  2. Cardiovascular Responses to Caffeine by Gender and Pubertal Stage

    PubMed Central

    Ziegler, Amanda M.; Graczyk, Adam; Bendlin, Ashley; Sion, Teresa; Vattana, Karina

    2014-01-01

    BACKGROUND: Caffeine use is on the rise among children and adolescents. Previous studies from our laboratory reported gender differences in the effects of caffeine in adolescents. The purpose of this study was to test the hypotheses that gender differences in cardiovascular responses to caffeine emerge after puberty and that cardiovascular responses to caffeine differ across the phases of the menstrual cycle. METHODS: To test these hypotheses, we examined heart rate and blood pressure before and after administration of placebo and 2 doses of caffeine (1 and 2 mg/kg) in prepubertal (8- to 9-year-olds; n = 52) and postpubertal (15- to 17-year-olds; n = 49) boys (n = 54) and girls (n = 47) by using a double-blind, placebo-controlled, dose-response design. RESULTS: There was an interaction between gender and caffeine dose, with boys having a greater response to caffeine than girls. In addition, we found interactions between pubertal phase, gender, and caffeine dose, with gender differences present in postpubertal, but not in prepubertal, participants. Finally, we found differences in responses to caffeine across the menstrual cycle in post-pubertal girls, with decreases in heart rate greater in the midluteal phase and blood pressure increases greater in the midfollicular phase of the menstrual cycle. CONCLUSIONS: These data suggest that gender differences in response to caffeine emerge after puberty. Future research will determine the extent to which these gender differences are mediated by physiological factors, such as steroid hormones, or psychosocial factors, such as more autonomy and control over beverage purchases. PMID:24935999

  3. Hormonal, cardiovascular, and subjective responses to acute stress in smokers

    PubMed Central

    de Wit, Harriet

    2009-01-01

    Rationale There are complex relationships between stress and smoking; smoking may reduce the emotional discomfort of stress, yet nicotine activates stress systems and may alter responses to acute stress. It is important to understand how smoking affects physiological and psychological outcomes after stress and how these may interact to motivate smoking. Objectives This study aimed to examine the magnitude and time course of hormonal, cardiovascular, and psychological responses to acute psychosocial stress in smokers and non-smokers to investigate whether responses to acute stress are altered in smokers. Materials and methods Healthy male non-smokers (n=20) and smokers (n=15) participated in two experimental sessions involving a standardized public speaking stress procedure and a control non-stressful task. The outcome measures included self-reported mood, cardiovascular measures (heart rate and blood pressure), and plasma hormone levels (noradrenaline, cortisol, progesterone, and allopregnanolone). Results Smokers exhibited blunted increases in cortisol after the Trier Social Stress Test, and they reported greater and more prolonged subjective agitation than non-smokers. Stress-induced changes in progesterone were similar between smokers and non-smokers, although responses overall were smaller among smokers. Stress did not significantly alter levels of allopregnanolone, but smokers exhibited lower plasma concentrations of this neurosteroid. Conclusions These findings suggest that smoking dampens hormonal responses to stress and prolongs subjective discomfort. Dysregulated stress responses may represent a breakdown in the body’s ability to cope efficiently and effectively with stress and may contribute to smokers’ susceptibility to acute stress, especially during abstinence. PMID:18936915

  4. The cardiovascular response to passive movement is joint dependent.

    PubMed

    Burns, Keith J; Pollock, Brandon S; McDaniel, John

    2016-03-01

    The cardiovascular responses to passive limb movement (PLM) at the knee are well established, however, responses to PLM at other joints involving smaller muscle volume are unknown. To compare the cardiovascular responses to passive movement at other joints, 10 participants underwent a PLM protocol in which the wrist, elbow, ankle, and knee joints were passively extended and flexed at 1 Hz for 1 min. Heart rate (HR), mean arterial blood pressure (MAP), and arterial blood flow to that limb segment (BF) were measured and vascular conductance (VC) was calculated for a 30-sec baseline period and for 3-sec intervals throughout PLM protocols. PLM of the knee and elbow resulted in significant increases in BF and VC from baseline values with peak values 180% (P < 0.001) greater than baseline. PLM of the elbow resulted in significant increases in BF and VC from baseline values with peak values 109% and 115% (P < 0.001) greater than baseline, respectively. No changes in BF and VC were observed in the ankle and wrist. Furthermore, the greater increase in blood flow per limb segment volume in the thigh and upper arm (62.8 ± 36.5 and 55.5 ± 30.3 mL min(-1) L(-1), respectively) compared to the forearm and lower leg (23.6 ± 16.7 and 19.1 ± 10.3 mL min(-1) L(-1), respectively) indicates the limb volume is not solely responsible for the differences in the hyperemic responses. These data indicate that the use of PLM to assess vascular function or as a rehabilitation modality to maintain vascular health may be most appropriate for the muscles that span the elbow and knee. PMID:26997626

  5. Physical fitness and cardiovascular response to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Raven, P. B.; Rohm-Young, D.; Blomqvist, C. G.

    1984-01-01

    Klein et al. (1977) have questioned the concept of endurance training as an appropriate means of preparing for prolonged space flights. Their opinion was mainly based on reports of endurance athletes who had a decreased tolerance to orthostatic or gravitational stress induced by lower body negative pressure (LBNP), upright tilt, or whole body water immersion. The present investigation had the objective to determine if the hemodynamic response to LBNP is different between a high and average fit group of subjects. In addition, the discrete aspect of cardiovascular function which had been altered by chronic training was to be identified. On the basis of the results of experiments conducted with 14 young male volunteers, it is concluded that the reflex response to central hypovolemia is altered by endurance exercise training.

  6. Failure to produce response variability with reinforcement

    PubMed Central

    Schwartz, Barry

    1982-01-01

    Two experiments attempted to train pigeons to produce variable response sequences. In the first, naive pigeons were exposed to a procedure requiring four pecks on each of two keys in any order, with a reinforcer delivered only if a given sequence was different from the preceding one. In the second experiment, the same pigeons were exposed to this procedure after having been trained successfully to alternate between two specific response sequences. In neither case did any pigeon produce more than a few different sequences or obtain more than 50% of the possible reinforcers. Stereotyped sequences developed even though stereotypy was not reinforced. It is suggested that reinforcers have both hedonic and informative properties and that the hedonic properties are responsible for sterotyped repetition of reinforced responses, even when stereotypy is negatively related to reinforcer delivery. PMID:16812263

  7. Autonomic and cardiovascular responses of preschool children to television programs.

    PubMed

    Gröer, M; Howell, M

    1990-01-01

    This exploratory study examined the heart rates (HR) and skin temperatures (ST) of 18 preschool children while they viewed two clips of everyday children's television (TV) programming. The measurements were made in a day care setting, in a naturalistic environment designed to mimic the real world of children's TV viewing. The purpose of the study was to determine whether cardiovascular and autonomic arousal to TV programming might occur in some children. Since a large body of psychosocial literature addresses the affects of TV violence on children, HR and ST were examined during exposure to scenes from Mr. Roger's Neighborhood and G.I. Joe cartoons. The Mr. Roger's clip was slow, rhythmic, prosocial, and nonviolent, while the G.I. Joe clip was fast-paced, staccato, colorful, and full of verbal and action violence. The study found a significant effect of exposure to the cartoon violence on HR, with HR increasing. ST decreased, but not significantly, and there was a significant effect of time on the ST, due possibly to habituation. This finding has relevance to nursing assessment, intervention, and education of parents and children, since TV viewing is a pervasive cultural phenomenon. The possibility of excessive or inappropriate autonomic and cardiovascular responsiveness in some children to TV must be considered. PMID:2213521

  8. Melatonin modulates the fetal cardiovascular defense response to acute hypoxia.

    PubMed

    Thakor, Avnesh S; Allison, Beth J; Niu, Youguo; Botting, Kimberley J; Serón-Ferré, Maria; Herrera, Emilio A; Giussani, Dino A

    2015-08-01

    Experimental studies in animal models supporting protective effects on the fetus of melatonin in adverse pregnancy have prompted clinical trials in human pregnancy complicated by fetal growth restriction. However, the effects of melatonin on the fetal defense to acute hypoxia, such as that which may occur during labor, remain unknown. This translational study tested the hypothesis, in vivo, that melatonin modulates the fetal cardiometabolic defense responses to acute hypoxia in chronically instrumented late gestation fetal sheep via alterations in fetal nitric oxide (NO) bioavailability. Under anesthesia, 6 fetal sheep at 0.85 gestation were instrumented with vascular catheters and a Transonic flow probe around a femoral artery. Five days later, fetuses were exposed to acute hypoxia with or without melatonin treatment. Fetal blood was taken to determine blood gas and metabolic status and plasma catecholamine concentrations. Hypoxia during melatonin treatment was repeated during in vivo NO blockade with the NO clamp. This technique permits blockade of de novo synthesis of NO while compensating for the tonic production of the gas, thereby maintaining basal cardiovascular function. Melatonin suppressed the redistribution of blood flow away from peripheral circulations and the glycemic and plasma catecholamine responses to acute hypoxia. These are important components of the fetal brain sparing response to acute hypoxia. The effects of melatonin involved NO-dependent mechanisms as the responses were reverted by fetal treatment with the NO clamp. Melatonin modulates the in vivo fetal cardiometabolic responses to acute hypoxia by increasing NO bioavailability. PMID:25908097

  9. Melatonin modulates the fetal cardiovascular defense response to acute hypoxia

    PubMed Central

    Thakor, Avnesh S; Allison, Beth J; Niu, Youguo; Botting, Kimberley J; Serón-Ferré, Maria; Herrera, Emilio A; Giussani, Dino A

    2015-01-01

    Experimental studies in animal models supporting protective effects on the fetus of melatonin in adverse pregnancy have prompted clinical trials in human pregnancy complicated by fetal growth restriction. However, the effects of melatonin on the fetal defense to acute hypoxia, such as that which may occur during labor, remain unknown. This translational study tested the hypothesis, in vivo, that melatonin modulates the fetal cardiometabolic defense responses to acute hypoxia in chronically instrumented late gestation fetal sheep via alterations in fetal nitric oxide (NO) bioavailability. Under anesthesia, 6 fetal sheep at 0.85 gestation were instrumented with vascular catheters and a Transonic flow probe around a femoral artery. Five days later, fetuses were exposed to acute hypoxia with or without melatonin treatment. Fetal blood was taken to determine blood gas and metabolic status and plasma catecholamine concentrations. Hypoxia during melatonin treatment was repeated during in vivo NO blockade with the NO clamp. This technique permits blockade of de novo synthesis of NO while compensating for the tonic production of the gas, thereby maintaining basal cardiovascular function. Melatonin suppressed the redistribution of blood flow away from peripheral circulations and the glycemic and plasma catecholamine responses to acute hypoxia. These are important components of the fetal brain sparing response to acute hypoxia. The effects of melatonin involved NO-dependent mechanisms as the responses were reverted by fetal treatment with the NO clamp. Melatonin modulates the in vivo fetal cardiometabolic responses to acute hypoxia by increasing NO bioavailability. PMID:25908097

  10. Essential Hypertension: Cardiovascular Response to Breath Hold Combined with Exercise.

    PubMed

    Hoffmann, U; Urban, P; Koschate, J; Drescher, U; Pfister, R; Michels, G

    2015-07-01

    Essential hypertension (EH) is a widespread disease and might be prevalent in apnea divers and master athletes. Little is known about the influence of EH and the antihypertensive drugs (AHD) on cardiovascular reactions to combined breath hold (BH) and exercise. In this pilot study, healthy divers (HCON) were compared with treated hypertensive divers with regard to heart rate (HR) and mean blood-pressure (MAP) responses to BH, exercise and the combination of both. Ten subjects with EH and ten healthy divers were tested. 3 different 20 s stimuli were applied: BH combined with 30 W or 150 W and 150 W without BH. The time-charts during the stress intervals and during recovery were compared. Subjects treated with an angiotensin-converting enzyme (ACE) inhibitor showed higher changes for MAP values if breath hold was performed. HR responses were obviously changed if a β-blocker was part of the medication. One subject showed extreme MAP responses to all stimuli and conspicuous HR if BH was involved. The modulation of HR-/MAP-response in EH subjects depends on the mechanisms of antihypertensive agents. The combination of an ACE inhibitor and a β-blocker may give the best protection. It is recommended to include short apnea tests in the fitness-to-dive examination to individually predict potential endangerment. PMID:25875316

  11. Brain injury causes loss of cardiovascular response to hemorrhagic shock.

    PubMed

    Fulton, R L; Flynn, W J; Mancino, M; Bowles, D; Cryer, H M

    1993-01-01

    The combined cardiovascular effects of hemorrhagic shock and mechanical brain injury were modeled in five groups of pigs. Standard and hypertonic saline resuscitation of hypotension were evaluated. Changes in mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), intracranial pressure (ICP), and brain water were measured. Brain injury (BI) was produced with a fluid percussion device that generated an extradural pressure of 3.5 x 10(5) N/m2 for 400 msec. Shock was caused by bleeding to a MAP of 60 mm Hg for 60 minutes and then resuscitated with shed blood only or shed blood plus 0.9% or 1.8% saline. Brain-injured only and shocked-only pigs served as controls. We found that brain injury alone caused refractory hypotension. Less shed blood was required to produce shock in brain injured animals (p < .05). Shock accompanied by brain injury was not reversed with crystalloid solutions. Volumes of saline required to restore blood pressure were large (> 6 L in 3 hours). 1.8% saline produced less rise in ICP than 0.9% saline but was less effective in restoring blood pressure. Brain edema was not decreased with 1.8% saline. Brain injury altered vascular compensation to hemorrhage and made accepted resuscitative measures ineffective. PMID:8512886

  12. Autonomic cardiovascular responses to smoke exposure in conscious rats

    SciTech Connect

    Nakamura, T.; Hayashida, Y. )

    1992-05-01

    Autonomic cardiovascular responses and the change in renal sympathetic nerve activity (RSNA) in response to smoke exposure were investigated in unrestrained conscious rats. Smoke exposure caused a prominent increase in RSNA (to 557.3 +/- 221.9% of the control level) and plasma norepinephrine (from 0.18 +/- 0.08 (control) to 0.66 +/- 0.22 ng/ml (at peak response of smoke exposure)), a slight increase in arterial blood pressure (from 89.6 +/- 3.3 to 103.6 +/- 3.8 mmHg), and marked bradycardia (from 386.6 +/- 12.8 to 231.3 +/- 20.6 beats/min). Respiratory rate in conscious rats was initially increased (from 1.6 +/- 0.1 to 6.1 +/- 0.3 breaths/s) but was decreased (to 0.9 +/- 0.1 breaths/s) at the peak phase of the cardiovascular responses to smoke inhalation. Blood gases and pH reflected these changes in respiratory rate to some extent. Sinoaortic denervation did not attenuate the bradycardia (from 402 +/- 17.5 to 255.8 +/- 16.2 beats/min) or increase in RSNA (to 413.4 +/- 74.9%) that occurred during smoke inhalation. Atropine sulfate abolished the bradycardic response (from 440.4 +/- 13.8 to 485.4 +/- 8.6 beats/min). Initial tachypnea was also observed in both sinoaortic denervated rats and atropine-treated rats. Anesthesia, induced by pentobarbital sodium (30 mg/kg iv) or alpha-chloralose (65 mg/kg iv), abolished the bradycardia, the increase in RSNA, and the change in respiratory rate caused by smoke exposure. Ablation of the olfactory lobes also greatly attenuated the smoke-induced increase in RSNA (to 150.9 +/- 22.9%), bradycardia (from 372.9 +/- 19.6 to 376.3 +/- 24.1 beats/min), and the respiratory change.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Acute Cardiovascular Response to Sign Chi Do Exercise

    PubMed Central

    Rogers, Carol E.; Carlson, John; Garver, Kayla

    2015-01-01

    Safe and gentle exercise may be important for older adults overcoming a sedentary lifestyle. Sign Chi Do (SCD), a novel form of low impact exercise, has shown improved balance and endurance in healthy older adults, and there have been no SCD-related injuries reported. Sedentary older adults are known to have a greater cardiovascular (CV) response to physical activity than those who regularly exercise. However their CV response to SCD is unknown. This study explored the acute CV response of older adults to SCD. Cross-sectional study of 34 sedentary and moderately active adults over age 55 with no previous experience practicing SCD. Participants completed a 10 min session of SCD. CV outcomes of heart rate, blood pressure, rate pressure product were recorded at 0, 5, 10 min of SCD performance, and after 10 min of rest. HR was recorded every minute. There was no difference in CV scores of sedentary and moderately active older adults after a session of SCD-related activity. All CV scores increased at 5 min, were maintained at 10 min, and returned to baseline within 10 min post SCD (p < 0.05). SCD may be a safe way to increase participation in regular exercise by sedentary older adults.

  14. Cardiovascular responses to apneic facial immersion during altered cardiac filling.

    PubMed

    Journeay, W Shane; Reardon, Francis D; Kenny, Glen P

    2003-06-01

    The hypothesis that reduced cardiac filling, as a result of lower body negative pressure (LBNP) and postexercise hypotension (PEH), would attenuate the reflex changes to heart rate (HR), skin blood flow (SkBF), and mean arterial pressure (MAP) normally induced by facial immersion was tested. The purpose of this study was to investigate the cardiovascular control mechanisms associated with apneic facial immersion during different cardiovascular challenges. Six subjects randomly performed 30-s apneic facial immersions in 6.0 +/- 1.2 degrees C water under the following conditions: 1) -20 mmHg LBNP, 2) +40 mmHg lower body positive pressure (LBPP), 3) during a period of PEH, and 4) normal resting (control). Measurements included SkBF at one acral (distal phalanx of the thumb) and one nonacral region of skin (ventral forearm), HR, and MAP. Facial immersion reduced HR and SkBF at both sites and increased MAP under all conditions (P < 0.05). Reduced cardiac filling during LBNP and PEH significantly attenuated the absolute HR nadir observed during the control immersion (P < 0.05). The LBPP condition did not result in a lower HR nadir than control but did result in a nadir significantly lower than that of the LBNP and PEH conditions (P < 0.05). No differences were observed in either SkBF or MAP between conditions; however, the magnitude of SkBF reduction was greater at the acral site than at the nonacral site for all conditions (P < 0.05). These results suggest that the cardiac parasympathetic response during facial immersion can be attenuated when cardiac filling is compromised. PMID:12598488

  15. Cardiovascular and inflammatory response to cholecystokinin during endotoxemic shock.

    PubMed

    Saia, Rafael Simone; Bertozi, Giuliana; Mestriner, Fabíola Leslie; Antunes-Rodrigues, José; Queiróz Cunha, Fernando; Cárnio, Evelin Capellari

    2013-01-01

    Cholecystokinin (CCK) was first described as a gastrointestinal hormone, but its receptors have been located in cardiac and vascular tissues, as well as in immune cells. Our aims were to investigate the role of CCK on lipopolysaccharide (LPS)-induced hypotension and its ability to modulate previously reported inflammatory mediators, therefore affecting cardiovascular function. To conduct these experiments, rats had their jugular vein cannulated for drug administration, and also, the femoral artery cannulated for mean arterial pressure (MAP) and heart rate records. Endotoxemia induced by LPS from Escherichia coli (1.5 mg/kg; i.v.) stimulated the release of CCK, a progressive drop in MAP, and increase in heart rate. Plasma tumor necrosis factor α (TNF-α), interleukin 10 (IL-10), nitrate, vasopressin, and lactate levels were elevated in the endotoxemic rats. The pretreatment with proglumide (nonselective CCK antagonist; 30 mg/kg; i.p.) aggravated the hypotension and also increased plasma TNF-α and lactate levels. On the other hand, CCK (0.4 μg/kg; i.v.) administered before LPS significantly restored MAP, reduced aortic and hepatic inducible nitric oxide synthase (iNOS) production, and elevated plasma vasopressin and IL-10 concentrations; it did not affect TNF-α. Physiological CCK concentration reduced nitrite and iNOS synthesis by peritoneal macrophages, possibly through a self-regulatory IL-10-dependent mechanism. Together, these data suggest a new role for the peptide CCK in modulating MAP, possibly controlling the inflammatory response, stimulating the anti-inflammatory cytokine, IL-10, and reducing vascular and macrophage iNOS-derived nitric oxide production. Based on these findings, CCK could be used as an adjuvant therapeutic agent to improve cardiovascular function. PMID:23247127

  16. Divergent Associations of Antecedent- and Response-Focused Emotion Regulation Strategies with Midlife Cardiovascular Disease Risk

    PubMed Central

    Loucks, Eric B.; Buka, Stephen L.; Kubzansky, Laura D.

    2014-01-01

    Background It is not known whether various forms of emotion regulation are differentially related to cardiovascular disease risk. Purpose The purpose of this study is to assess whether antecedent and response-focused emotion regulation would have divergent associations with likelihood of developing cardiovascular disease. Methods Two emotion regulation strategies were examined: reappraisal (antecedent-focused) and suppression (response-focused). Cardiovascular disease risk was assessed with a validated Framingham algorithm that estimates the likelihood of developing CVD in 10 years. Associations were assessed among 373 adults via multiple linear regression. Pathways and gender-specific associations were also considered. Results One standard deviation increases in reappraisal and suppression were associated with 5.9 % lower and 10.0 % higher 10-year cardiovascular disease risk, respectively, in adjusted analyses. Conclusions Divergent associations of antecedent and response-focused emotion regulation with cardiovascular disease risk were observed. Effective emotion regulation may promote cardiovascular health. PMID:24570218

  17. Metabolic and Cardiovascular Response to Shallow Water Exercise in Young and Older Women.

    ERIC Educational Resources Information Center

    Campbell, Jennifer A.; D'Acquisto, Leo J.; D'Acquisto, Debra M.; Cline, Michael G.

    2003-01-01

    Compared the metabolic and cardiovascular responses of young and older women while performing shallow water exercise (SWE). Overall, SWE elicited metabolic and cardiovascular responses that met American College of Sports Medicine's guidelines for establishing health benefits. Older females self-selected a greater relative exercise intensity during…

  18. Computational modeling of cardiovascular response to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Heldt, Thomas; Shim, Eun B.; Kamm, Roger D.; Mark, Roger G.

    2002-01-01

    The objective of this study is to develop a model of the cardiovascular system capable of simulating the short-term (< or = 5 min) transient and steady-state hemodynamic responses to head-up tilt and lower body negative pressure. The model consists of a closed-loop lumped-parameter representation of the circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes. Model parameters are largely based on literature values. Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. On the basis of experimental evidence, we adjusted some model parameters to simulate experimental data. Orthostatic stress simulations are not statistically different from experimental data (two-sided test of significance with Bonferroni adjustment for multiple comparisons). Transient response characteristics of heart rate to tilt also compare well with reported data. A case study is presented on how the model is intended to be used in the future to investigate the effects of post-spaceflight orthostatic intolerance.

  19. Computational modeling of cardiovascular response to orthostatic stress.

    PubMed

    Heldt, Thomas; Shim, Eun B; Kamm, Roger D; Mark, Roger G

    2002-03-01

    The objective of this study is to develop a model of the cardiovascular system capable of simulating the short-term (< or = 5 min) transient and steady-state hemodynamic responses to head-up tilt and lower body negative pressure. The model consists of a closed-loop lumped-parameter representation of the circulation connected to set-point models of the arterial and cardiopulmonary baroreflexes. Model parameters are largely based on literature values. Model verification was performed by comparing the simulation output under baseline conditions and at different levels of orthostatic stress to sets of population-averaged hemodynamic data reported in the literature. On the basis of experimental evidence, we adjusted some model parameters to simulate experimental data. Orthostatic stress simulations are not statistically different from experimental data (two-sided test of significance with Bonferroni adjustment for multiple comparisons). Transient response characteristics of heart rate to tilt also compare well with reported data. A case study is presented on how the model is intended to be used in the future to investigate the effects of post-spaceflight orthostatic intolerance. PMID:11842064

  20. Cardiovascular responses to microgravity - Adaptation, maladjustment, and countermeasures

    NASA Technical Reports Server (NTRS)

    Gaffney, F. Andrew

    1989-01-01

    Humans have worked in space for up to 237 days without significant inflight limitations, although major cardiovascular disability is seen following space flight of even a few days duration. Most of the cardiovascular research on microgravity deconditioning has been observational in character. Detailed studies of mechanisms and causes of postflight exercise intolerance, low blood pressure and fainting in astronauts and cosmonauts have not been done, despite almost 30 years of manned space flight. A review of possible mechanisms of postflight cardiovascular deconditioning and directions for study is provided.

  1. Cardiovascular responses to static exercise in distance runners and weight lifters

    NASA Technical Reports Server (NTRS)

    Longhurst, J. C.; Kelly, A. R.; Gonyea, W. J.; Mitchell, J. H.

    1980-01-01

    Three groups of athletes including long-distance runners, competitive and amateur weight lifters, and age- and sex-matched control subjects have been studied by hemodynamic and echocardiographic methods in order to determine the effect of the training programs on the cardiovascular response to static exercise. Blood pressure, heart rate, and double product data at rest and at fatigue suggest that competitive endurance (dynamic exercise) training alters the cardiovascular response to static exercise. In contrast to endurance exercise, weight lifting (static exercise) training does not alter the cardiovascular response to static exercise: weight lifters responded to static exercise in a manner very similar to that of the control subjects.

  2. Mathematical modeling of human cardiovascular system for simulation of orthostatic response

    NASA Technical Reports Server (NTRS)

    Melchior, F. M.; Srinivasan, R. S.; Charles, J. B.

    1992-01-01

    This paper deals with the short-term response of the human cardiovascular system to orthostatic stresses in the context of developing a mathematical model of the overall system. It discusses the physiological issues involved and how these issues have been handled in published cardiovascular models for simulation of orthostatic response. Most of the models are stimulus specific with no demonstrated capability for simulating the responses to orthostatic stimuli of different types. A comprehensive model incorporating all known phenomena related to cardiovascular regulation would greatly help to interpret the various orthostatic responses of the system in a consistent manner and to understand the interactions among its elements. This paper provides a framework for future efforts in mathematical modeling of the entire cardiovascular system.

  3. Mathematical modeling of human cardiovascular system for simulation of orthostatic response.

    PubMed

    Melchior, F M; Srinivasan, R S; Charles, J B

    1992-06-01

    This paper deals with the short-term response of the human cardiovascular system to orthostatic stresses in the context of developing a mathematical model of the overall system. It discusses the physiological issues involved and how these issues have been handled in published cardiovascular models for simulation of orthostatic response. Most of the models are stimulus specific with no demonstrated capability for simulating the responses to orthostatic stimuli of different types. A comprehensive model incorporating all known phenomena related to cardiovascular regulation would greatly help to interpret the various orthostatic responses of the system in a consistent manner and to understand the interactions among its elements. This paper provides a framework for future efforts in mathematical modeling of the entire cardiovascular system. PMID:1621848

  4. Long-term moderate exercise accelerates the recovery of stress-evoked cardiovascular responses.

    PubMed

    Hsu, Yuan-Chang; Tsai, Sheng-Feng; Yu, Lung; Chuang, Jih-Ing; Wu, Fong-Sen; Jen, Chauying J; Kuo, Yu-Min

    2016-01-01

    Psychological stress is an important global health problem. It is well documented that stress increases the incidences of various cardiovascular disorders. Regular exercise is known to reduce resting blood pressure (BP) and heart rate (HR). This study was designed to clarify the effects of long-term exercise on stress-evoked cardiovascular responses and to emphasize post-stress recovery effects. Male Wistar rats underwent 8 weeks of moderate treadmill training, with cardiovascular responses, autonomic nervous system activities and local Fos reactivity changes in the cardiovascular regulation center were monitored before, during and after immobilization stress. A spectral analysis of cardiovascular parameters was used to examine autonomic nervous activities. We found that long-term exercise (i) lowered resting BP, HR and sympathetic activity, but increased resting parasympathetic activity and baroreflex sensitivity (BRS); (ii) accelerated post-stress recovery of stress-evoked cardiovascular and sympathetic responses along with increased BRS and (iii) accelerated post-stress recovery of stress-evoked neuron activations in the paraventricular nucleus, but delayed it in the nucleus of the tractus solitarius. We conclude that, in rats, long-term exercise accelerated recovery of stress-evoked cardiovascular responses differentially altering hypothalamic and medullar neuron activities. PMID:26473638

  5. Type A Behavior and Cardiovascular Responsivity in Preschoolers.

    ERIC Educational Resources Information Center

    Brown, Marie Scott; Tanner, Christine

    This study investigated Type A behavior in preschool children and its relation to cardiovascular reactivity. One hundred forty-four children from 3.5 to 6.5 years old were categorized by their teachers according to the Matthews Youth Test for Health (MYTH) as Type A, Mixed, or Type B. The children's pulse, pulse rate variability, and blood…

  6. Earthworms Produce phytochelatins in Response to Arsenic

    PubMed Central

    Lawlor, Alan J.; Bennett, Mark H.; Morris, Ceri A.; Kille, Peter; Svendsen, Claus; Spurgeon, David J.; Bundy, Jacob G.

    2013-01-01

    Phytochelatins are small cysteine-rich non-ribosomal peptides that chelate soft metal and metalloid ions, such as cadmium and arsenic. They are widely produced by plants and microbes; phytochelatin synthase genes are also present in animal species from several different phyla, but there is still little known about whether these genes are functional in animals, and if so, whether they are metal-responsive. We analysed phytochelatin production by direct chemical analysis in Lumbricus rubellus earthworms exposed to arsenic for a 28 day period, and found that arsenic clearly induced phytochelatin production in a dose-dependent manner. It was necessary to measure the phytochelatin metabolite concentrations directly, as there was no upregulation of phytochelatin synthase gene expression after 28 days: phytochelatin synthesis appears not to be transcriptionally regulated in animals. A further untargetted metabolomic analysis also found changes in metabolites associated with the transsulfuration pathway, which channels sulfur flux from methionine for phytochelatin synthesis. There was no evidence of biological transformation of arsenic (e.g. into methylated species) as a result of laboratory arsenic exposure. Finally, we compared wild populations of earthworms sampled from the field, and found that both arsenic-contaminated and cadmium-contaminated mine site worms had elevated phytochelatin concentrations. PMID:24278409

  7. Cardiovascular and hormonal (aldosterone) responses in a rat model which mimics responses to weightlessness

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, J. M.

    1984-01-01

    Cardiovascular responses and fluid/electrolyte shifts seen during spaceflight have been attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended, head-down tilt of 15-20 deg) is used to model these responses. This study documents that elevated blood pressures in AO rats are sustained for periods of up to seven days, compared with presuspension values. Increased blood pressures in AO rats suggests a specific response to AO positioning, potentially relatable to a cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured. Circulating aldosterone concentrations were seen to increase approximately 100 percent during seven days of AO suspension, concurrently with a pronounced natriuresis. These results suggest that aldosterone may not be involved in the long term regulation of increased Na(+) excretion in AO animals. These studies continue to show the usefulness of models for the development of animal protocols for space flight.

  8. Effect of fluid countermeasures of varying osmolarity on cardiovascular responses to orthostatic stress

    NASA Technical Reports Server (NTRS)

    Davis, John E.

    1989-01-01

    Current operational procedures for shuttle crewmembers include the ingestion of a fluid countermeasure approximately 2 hours before reentry into the earth's gravitational field. The ingestion of the fluid countermeasure is thought to restore plasma volume and improve orthostatic responses upon reentry. The present countermeasure consists of ingesting salt tablets and water to achieve an isotonic solution. It has yet to be determined whether this is the optimal drink to restore orthostatic tolerance. It is also not known whether the drink solution is effective in increasing plasma volume. The purpose here is to evaluate the effectiveness of drink solutions of different osmolarity on restoring plasma volume and orthostatic responses. A hypertonic drink solution was more effective in restoring plasma volume after dehydration than an isotonic solution. However, there were no differences in their effects on an orthostatic challenge. These data suggest that the plasma volume differences produced in this study were not sufficient to produce differences in the cardiovascular responses to an orthostatic challenge, or there are other changes that occur during space flight that are more important in determining orthostatic intolerance.

  9. Predictions of cardiovascular responses during STS reentry using mathematical models

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.; Srinivasan, R.

    1985-01-01

    The physiological adaptation to weightless exposure includes cardiovascular deconditioning arising in part from a loss of total circulating blood volume and resulting in a reduction of orthostatic tolerance. The crew of the Shuttle orbiter are less tolerant to acceleration forces in the head-to-foot direction during the reentry phase of the flight at a time they must function at a high level of performance. The factors that contribute to orthostatic intolerance during and following reentry and to predict the likelihood of impaired crew performance are evaluated. A computer simulation approach employing a mathematical model of the cardiovascular system is employed. It is shown that depending on the severity of blood volume loss, the reentry acceleration stress may be detrimental to physiologic function and may place the physiologic status of the crew near the borderline of some type of impairment. They are in agreement with conclusions from early ground-based experiments and from observations of early Shuttle flights.

  10. Cardiovascular Response Identification Based on Nonlinear Support Vector Regression

    NASA Astrophysics Data System (ADS)

    Wang, Lu; Su, Steven W.; Chan, Gregory S. H.; Celler, Branko G.; Cheng, Teddy M.; Savkin, Andrey V.

    This study experimentally investigates the relationships between central cardiovascular variables and oxygen uptake based on nonlinear analysis and modeling. Ten healthy subjects were studied using cycle-ergometry exercise tests with constant workloads ranging from 25 Watt to 125 Watt. Breath by breath gas exchange, heart rate, cardiac output, stroke volume and blood pressure were measured at each stage. The modeling results proved that the nonlinear modeling method (Support Vector Regression) outperforms traditional regression method (reducing Estimation Error between 59% and 80%, reducing Testing Error between 53% and 72%) and is the ideal approach in the modeling of physiological data, especially with small training data set.

  11. Let's Produce Culturally Responsive Pedagogues on Deck

    ERIC Educational Resources Information Center

    Jett, Christopher C.

    2012-01-01

    In this response, I extend the conversation started by Hayes and Juarez (2012) by highlighting how culturally responsive teaching is spoken in one teacher education program where I worked and served in the preparation of middle-level teachers. I also share my reflections concerning this idea and pose questions for critical thought, dialogue, and…

  12. Mechanical signaling and the cellular response to extracellular matrix in angiogenesis and cardiovascular physiology

    NASA Technical Reports Server (NTRS)

    Ingber, Donald E.

    2002-01-01

    Great advances have been made in the identification of the soluble angiogenic factors, insoluble extracellular matrix (ECM) molecules, and receptor signaling pathways that mediate control of angiogenesis--the growth of blood capillaries. This review focuses on work that explores how endothelial cells integrate these chemical signals with mechanical cues from their local tissue microenvironment so as to produce functional capillary networks that exhibit specialized form as well as function. These studies have revealed that ECM governs whether an endothelial cell will switch between growth, differentiation, motility, or apoptosis programs in response to a soluble stimulus based on its ability to mechanically resist cell tractional forces and thereby produce cell and cytoskeletal distortion. Transmembrane integrin receptors play a key role in this mechanochemical transduction process because they both organize a cytoskeletal signaling complex within the focal adhesion and preferentially focus mechanical forces on this site. Molecular filaments within the internal cytoskeleton--microfilaments, microtubules, and intermediate filaments--also contribute to the cell's structural and functional response to mechanical stress through their role as discrete support elements within a tensegrity-stabilized cytoskeletal array. Importantly, a similar form of mechanical control also has been shown to be involved in the regulation of contractility in vascular smooth muscle cells and cardiac myocytes. Thus, the mechanism by which cells perform mechanochemical transduction and the implications of these findings for morphogenetic control are discussed in the wider context of vascular development and cardiovascular physiology.

  13. Cardiovascular Responses to Psychosocial Stress Reflect Motivation State in Adults Born at Extremely Low Birth Weight

    PubMed Central

    Pyhälä, Riikka; Hovi, Petteri; Räikkönen, Katri; Van Lieshout, Ryan J.; Boyle, Michael H.; Saigal, Saroj; Morrison, Katherine M.; Kajantie, Eero; Schmidt, Louis A.

    2015-01-01

    Background. Adults born extremely preterm appear to have more difficulty managing the stresses of early adulthood than their term-born peers. Objective. To examine the effects of being born at extremely low birth weight (ELBW; birth weight < 1000 g) versus at full term on cardiovascular responses to stress. Method. Cardiovascular responses were elicited during administration of a widely used laboratory stressor, the Trier Social Stress Test (TSST). Results. Term-born adults exhibited a larger decrease in total peripheral resistance and larger increase in cardiac output for TSST performance, reflecting greater resilience, than did ELBW adults. Furthermore, in ELBW participants but not controls, cardiovascular responses were correlated with anxiety, suggesting that their responses reflected feelings of stress. Conclusions. Skills-training and practice with relevant stressors may be necessary to increase the personal resources of ELBW participants for managing stress as they transition to adulthood. PMID:27335948

  14. Cardiovascular regulatory response to lower body negative pressure following blood volume loss

    NASA Technical Reports Server (NTRS)

    Shimizu, M.; Ghista, D. N.; Sandler, H.

    1979-01-01

    An attempt is made to explain the cardiovascular regulatory responses to lower body negative pressure (LBNP) stress, both in the absence of and following blood or plasma volume loss, the latter being factors regularly observed with short- or long-term recumbency or weightlessness and associated with resulting cardiovascular deconditioning. Analytical expressions are derived for the responses of mean venous pressure and blood volume pooled in the lower body due to LBNP. An analysis is presented for determining the HR change due to LBNP stress following blood volume loss. It is concluded that the reduced orthostatic tolerance following long-term space flight or recumbency can be mainly attributed to blood volume loss, and that the associated cardiovascular responses characterizing this orthostatic intolerance is elicited by the associated central venous pressure response.

  15. Cardiovascular Responses to Psychosocial Stress Reflect Motivation State in Adults Born at Extremely Low Birth Weight.

    PubMed

    Mathewson, Karen J; Pyhälä, Riikka; Hovi, Petteri; Räikkönen, Katri; Van Lieshout, Ryan J; Boyle, Michael H; Saigal, Saroj; Morrison, Katherine M; Kajantie, Eero; Schmidt, Louis A

    2015-01-01

    Background. Adults born extremely preterm appear to have more difficulty managing the stresses of early adulthood than their term-born peers. Objective. To examine the effects of being born at extremely low birth weight (ELBW; birth weight < 1000 g) versus at full term on cardiovascular responses to stress. Method. Cardiovascular responses were elicited during administration of a widely used laboratory stressor, the Trier Social Stress Test (TSST). Results. Term-born adults exhibited a larger decrease in total peripheral resistance and larger increase in cardiac output for TSST performance, reflecting greater resilience, than did ELBW adults. Furthermore, in ELBW participants but not controls, cardiovascular responses were correlated with anxiety, suggesting that their responses reflected feelings of stress. Conclusions. Skills-training and practice with relevant stressors may be necessary to increase the personal resources of ELBW participants for managing stress as they transition to adulthood. PMID:27335948

  16. Cardiovascular response of rats exposed to 60-Hz electric fields

    SciTech Connect

    Hilton, D.I.; Phillips, R.D.

    1980-01-01

    Recently, it has been reported that exposure to high-strength electric fields can influence electrocardiogram (ECG) patterns, heart rates, and blood pressures in various species of animals. Our studies were designed to evaluate these reported effects and to help clarify some of the disagreement present in the literature. Various cardiovascular variables were measured in Sprague-Dawley rats exposed or sham-exposed to 60-Hz electric fields at 80 to 100 kV/m for periods up to four months. No significant differences in heart rates, ECG patterns, blood pressures, or vascular reactivity were observed between exposed and sham-exposed rats after 8 hours, 40 hours, 1 month, or 4 months of exposure. Our studies cannot be directly compared to the work of other investigators because of differences in animal species and electric-field characteristics. However, our failure to detect any cardiovascular changes may have been the result of (1) eliminating secondary field effects such as shocks, audible noise, corona, and ozone; (2) minimizing steady-state microcurrents between the mouth of the animal and watering devices; and (3) minimizing electric-field-induced vibration of the electrodes and animal cages.

  17. Action of adenosine receptor antagonists on the cardiovascular response to defence area stimulation in the rat.

    PubMed Central

    St Lambert, J H; Dawid-Milner, M S; Silva-Carvalho, L; Spyer, K M

    1994-01-01

    1. The action of adenosine in the mediation of the cardiovascular changes associated with the defence reaction has been investigated in the rat using two A1 receptor antagonists. 2. Cumulative doses of 1,3 dipropyl-cyclopentylxanthine (DPCPX) (0.3-3 mg kg-1) and ethanol (0.03-0.25 ml) and bolus doses of DPCPX (3 mg kg-1) and 8-sulphophenyltheophylline (8-SPT) (20 mg kg-1) were given into alpha-chloralose, paralysed and artificially ventilated rats. Recordings were made of arterial blood pressure and heart rate. 3. Ethanol, the vehicle for DPCPX, failed to modify the magnitude of the defence response; however, cumulative doses of DPCPX produced a dose-dependent decrease in the HDA (hypothalamic defence area)-evoked increase in arterial blood pressure, accompanied by a similar fall in the magnitude of the evoked heart rate response. 4. The evoked rise in arterial blood pressure was reduced significantly by intravenous injection of DPCPX (3 mg kg-1) but not 8-SPT (20 mg kg-1), a purely peripherally acting adenosine antagonist. 5. These results suggest that adenosine acting at A1 receptors located in the central nervous system, is involved in the HDA-evoked pressor response. Whilst the site of action of the A1 receptors is not known, possible locations are discussed. PMID:7812606

  18. Effect of the prelaunch position on the cardiovascular response to standing.

    PubMed

    Gotshall, R W; Yumikura, S; Aten, L A

    1991-12-01

    Astronauts spend a minimum of 2 h in the reclined seated position (prelaunch position) prior to the launch of the Space Shuttle. This position favors a cephalad shift of blood volume and subsequent loss of body fluid volume, a physiologic situation associated with cardiovascular deconditioning and orthostatic intolerance following spaceflight. It is not known if the prelaunch position results in cardiovascular deconditioning and, therefore, impaired cardiovascular performance during standing. If so, this might hinder the ability of the crewmember to make an emergency egress from the shuttle during the launch. The purpose of this study was to evaluate the cardiovascular responses of men and women to the stand test before and after 2 h in the prelaunch position. Nine men and nine women performed the stand test before and after 2 h in the seated position (SIT), the prelaunch position (PL), or seated immersed to the neck in water (WI). Heart rate, blood pressure, and cardiac output were measured. Men had higher blood pressures than women and demonstrated increases in blood pressure with standing. There were no other gender differences. SIT did not alter the cardiovascular response to standing, while PL and WI resulted in greater increases in heart rate after 2 h in the position. This increase was only 4 to 7 beats/min greater than after SIT, and was the same for PL and WI. Thus, a small, but significant, degree of cardiovascular deconditioning occurred during the minimum time astronauts spend in the prelaunch position. PMID:1755793

  19. Maternal and fetal cardiovascular response to exercise during pregnancy.

    PubMed

    Veille, J C

    1996-08-01

    With the two-dimensional Doppler echocardiogram and M-mode echocardiogram, one can study maternal and fetal cardiovascular physiology during rest and exercise. Using such noninvasive techniques, studies indicate that left ventricular function is maintained even during vigorous bicycle exercise in healthy pregnant subjects during the second half of pregnancy. In early pregnancy, the left ventricle adapts to strenuous bicycle exercise by increasing its contractile reserve, enhancing ventricular emptying, whereas in late pregnancy, the left ventricle increases its preload reserve without significantly increasing its contractile reserve. Thus, women are "cardiovascularly" disadvantaged early in pregnancy. Using Doppler signals, early (E-passive) flow and late peak (A-active) flow reflect left ventricular diastolic filling properties. Using such techniques, we found that diastolic filling patterns are significantly influenced by pregnancy and that each trimester influences these diastolic filling patterns during upright bicycle exercise. Doppler studies of uteroplacental circulation during or after exercise have yielded conflicting results. Some have described an increase in "the vascular resistance" of this pelvic bed during strenuous exercise, whereas others have not. It seems safe to conclude that more studies are needed to elucidate this problem. Exercise does not seem to influence the resistivity index of the umbilical artery in either singleton or twins, and may even cause it to decrease. Ventricular diastolic filling properties of the fetal heart do not seem to be influenced by maternal bicycle exercise. Further studies are needed to determine if less active pregnant subjects, women with chronic hypertensive disorders, women with sickle cell anemia, or women with insulin-dependent diabetes adapt to exercise as well as their "normal" counterparts. PMID:8888451

  20. Cardiovascular and single-unit responses to microinjection of angiotensin II into the bed nucleus of the stria terminalis in rat.

    PubMed

    Kafami, M; Nasimi, A

    2015-08-01

    The bed nucleus of the stria terminalis (BST) is part of the limbic system located in the rostral forebrain. BST is involved in behavioral, neuroendocrine and autonomic functions, including cardiovascular regulation. The angiotensin II (Ang II) receptor, AT1, was found in the BST, however its effects on the cardiovascular system and on single-unit responses have not been studied yet. In the present study, Ang II was microinjected into the BST of anesthetized rats and cardiovascular and single-unit responses were recorded simultaneously. Furthermore the responses were re-tested after the microinjection of a blocker of the AT1 receptor, losartan, into the BST. We found that microinjection of Ang II into the BST produced a pressor response of 11±1mmHg for a duration of 2-8min. Ang II had no consistent effect on heart rate. It also produced two types of single-unit responses in the BST, short excitatory and long inhibitory. Blockade of AT1 receptors abolished both the cardiovascular and single-unit responses, indicating that the responses were mediated through AT1 receptors. These findings imply that Ang II may be utilized as a neurotransmitter and may play a role in returning blood pressure toward normal during hypotension. PMID:26026681

  1. Cardiovascular and cerebrovascular responses to acute hypoxia following exposure to intermittent hypoxia in healthy humans

    PubMed Central

    Foster, Glen E; Brugniaux, Julien V; Pialoux, Vincent; Duggan, Cailean T C; Hanly, Patrick J; Ahmed, Sofia B; Poulin, Marc J

    2009-01-01

    Intermittent hypoxia (IH) is thought to be responsible for many of the long-term cardiovascular consequences associated with obstructive sleep apnoea (OSA). Experimental human models of IH can aid in investigating the pathophysiology of these cardiovascular complications. The purpose of this study was to determine the effects of IH on the cardiovascular and cerebrovascular response to acute hypoxia and hypercapnia in an experimental human model that simulates the hypoxaemia experienced by OSA patients. We exposed 10 healthy, male subjects to IH for 4 consecutive days. The IH profile involved 2 min of hypoxia (nadir = 45.0 mmHg) alternating with 2 min of normoxia (peak = 88.0 mmHg) for 6 h. The cerebral blood flow response and the pressor responses to hypoxia and hypercapnia were assessed after 2 days of sham exposure, after each day of IH, and 4 days following the discontinuation of IH. Nitric oxide derivatives were measured at baseline and following the last exposure to IH. After 4 days of IH, mean arterial pressure increased by 4 mmHg (P < 0.01), nitric oxide derivatives were reduced by 55% (P < 0.05), the pressor response to acute hypoxia increased (P < 0.01), and the cerebral vascular resistance response to hypoxia increased (P < 0.01). IH alters blood pressure and cerebrovascular regulation, which is likely to contribute to the pathogenesis of cardiovascular and cerebrovascular disease in patients with OSA. PMID:19417094

  2. Review of extended producer responsibility: A case study approach.

    PubMed

    Gupt, Yamini; Sahay, Samraj

    2015-07-01

    Principles of extended producer responsibility have been the core of most of the recent policies and legislation dealing with the end-of-life management of recyclable goods. This article makes an exploratory review of 27 cases of extended producer responsibility from developed and developing economies with and without informal recycling, to ascertain the most important aspect of extended producer responsibility. A comparative analysis of the cases with respect to role of stakeholders in the upstream and downstream stages of the extended producer responsibility has been carried out. Further, the study uses exploratory factor analysis to determine the important aspects of the extended producer responsibility in practice using 13 variables identified from the review. Findings of the comparative analysis reveal that financial responsibility of the producers and separate collecting and recycling agencies contributed significantly to the success of the extended producer responsibility-based environmental policies. Regulatory provisions, take-back responsibility and financial flow come out to be the three most important aspects of the extended producer responsibility. Presence of informal sector had a negative impact on the regulatory provisions. The outcomes of this study could serve as a guideline for designing of effective extended producer responsibility-based policies. PMID:26185163

  3. Evolution of testosterone treatment over 25 years: symptom responses, endocrine profiles and cardiovascular changes

    PubMed Central

    Carruthers, Malcolm; Cathcart, Paul; Feneley, Mark R.

    2015-01-01

    Abstract Introduction: Testosterone treatment has evolved rapidly over the past 25 years as new, more effective and convenient methods have become available. This study reports experience with seven different methods, introduced on the market in the UK. Aim: To establish the symptom response when testosterone treatment was initiated on the basis of clinical features and symptoms of androgen deficiency, and the resulting endocrine, biochemical and physiological responses. Methods: Of 2693 patients attending the 3 Men’s Health Centers – The UK Androgen Study (UKAS), 2247 were treated. Treatments included pellet implants, oral testosterone undecanoate (Testocaps), mesterolone (Proviron), testosterone gel (Testogel), testosterone scrotal cream (Andromen) and scrotal gel (Tostran). Results: There was no correlation between initial testosterone level, initial symptom score or the success of treatment as defined by adequate resolution of symptoms. Despite the diverse endocrine patterns produced, the testosterone preparations appear equally safe over prolonged periods, with either no change or improvement of cardiovascular risk factors, especially in lowering cholesterol and diastolic blood pressure. Conclusions: It is suggested that because of excessive reliance on laboratory measures of androgens and undue safety concerns, many men who could benefit from symptom relief, improvement in related clinical conditions and given preventive medical benefits remain untreated. PMID:26218766

  4. Cardiovascular responses during orthostasis - Effect of an increase in maximal O2 uptake

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.; Montgomery, L. D.; Greenleaf, J. E.

    1984-01-01

    A study is described which tests the hypothesis that changes in aerobic activity (increases in maximum oxygen uptake) will reduce the effectiveness of cardiovascular reflexes to regulate blood pressure during orthostasis. The hypothesis was tested by measuring heart rate, blood pressure and blood volume responses in eight healthy male subjects before and after an eight-day endurance regimen. The results of the study suggest that the physiologic responses to orthostasis are dependent upon the rate of plasma volume loss and pooling, and are associated with training-induced hypervolemia. It is indicated that endurance type exercise training enhances cardiovascular adjustments during tilt. The implications of these results for the use of exercise training as a countermeasure and/or therapeutic method for the prevention of cardiovascular instability during orthostatic stress are discussed.

  5. Increasing Prescription Length Could Cut Cardiovascular Disease Burden And Produce Savings In South Africa.

    PubMed

    Gaziano, Thomas; Cho, Sylvia; Sy, Stephen; Pandya, Ankur; Levitt, Naomi S; Steyn, Krisela

    2015-09-01

    South Africa's rates of statin use are among the world's lowest, despite statins' demonstrated effectiveness for people with a high blood cholesterol level or history of cardiovascular disease. Almost 5 percent of the country's total mortality has been attributed to high cholesterol levels, fueled in part by low levels of statin adherence. Drawing upon experience elsewhere, we used a microsimulation model of cardiovascular disease to investigate the health and economic impacts of increasing prescription length from the standard thirty days to either sixty or ninety days, for South African adults on a stable statin regimen. Increasing prescription length to sixty or ninety days could save 1,694 or 2,553 lives per million adults, respectively. In addition, annual per patient costs related to cardiovascular disease would decrease by $152.41 and $210.29, respectively. Savings would largely accrue to patients in the form of time savings and reduced transportation costs, as a result of less frequent trips to the pharmacy. Increasing statin prescription length would both save resources and improve health outcomes in South Africa. PMID:26355061

  6. Frontal brain asymmetry and transient cardiovascular responses to the perception of humor.

    PubMed

    Papousek, Ilona; Schulter, Günter; Weiss, Elisabeth M; Samson, Andrea C; Freudenthaler, H Harald; Lackner, Helmut K

    2013-04-01

    The study examined the relationship of individual differences in prefrontal brain asymmetry, measured by the EEG in resting conditions, to the individual's responsivity in the context of humor (n=42). Several weeks after the EEG recording, immediate cardiovascular responses to the perception of humor and behavioral indicators of humor processing were obtained in an experimental paradigm involving non-verbal cartoons. Relatively greater resting activity in the left than right prefrontal cortex, particularly at the ventrolateral positions, was associated with faster detection of humor, a more pronounced cardiac response to the perception of humor (heart rate and cardiac output), and more accessible internal positive affective states (indicated by faster reports of amusement levels). The study confirms and extends findings of the relevance of prefrontal brain asymmetry to affective responsivity, contributing evidence in the domain of positive affect and humor, and demonstrating relationships to the immediate cardiovascular response pattern to an emotional event. PMID:23274171

  7. Cardiovascular and organ responses and adaptation responses to hypogravity in an experimental animal model.

    NASA Astrophysics Data System (ADS)

    Biondi, R.; Capodicasa, E.; Tassi, C.; Mezzasomal, L.; Benedetti, C.; Valiani, M.; Marconi, P.; Rossi, R.

    1995-10-01

    The head-down suspension (i.e antiorthostatic hypokinesia) rat is used to simulate weightlessness. However, little is known about cardiovascular and organ adaptation responses which, over a long time, can become pathologically significant. The purpose of this study was therefore to evaluate regional changes in the hematology parameters, Endotheline-1 (ET-1) concentration and urinary excretion of N-acetyl-β-D-glucosaminidase (EC 3.2.1.30) (NAG) in an experimental antiorthostatic rat model. The data indicate significant variations in the plasma ET-1 level in time, in the superior and inferior cava vessel blood of animals maintained for 10 days in hypogravity with respect to controls. These changes do not seem to be due to hemoconcentration. The increase in urinary NAG was observed during the first 24h of experiment, indicating renal stress, probably due to adverse blood flow variations within the organ. We conclude that the plasma ET-1 level changes could be responsible, overall for the blood flow variations in the kidney and renal stress could be the consequence of extended antiorthostatic hypokinesia. The ET-1 behaviour and urinary NAG excretion in rats exposed to antiorthostatic hypokjnetic hydynamia offer possibilities for understanding if these changes might be reversible or when they become pathological. This could give some relevant information about the effects of prolonged hypogravity during the space voyage.

  8. Assessing Cardiovascular Responses to Stressors in Individuals with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Groden, June; Goodwin, Matthew S.; Baron, M. Grace; Groden, Gerald; Velicer, Wayne F.; Lipsitt, Lewis P.; Hofmann, Stefan G.; Plummer, Brett

    2005-01-01

    Characteristics of persons with autism and other developmental disabilities may make this population especially vulnerable to the effects of stress. Prior research on stress and its measurement in this population is reviewed. Using a single-case multi-element design, this study explores the feasibility of measuring cardiovascular responses to four…

  9. Concord grape juice polyphenols and cardiovascular risk factors: dose-response relationships

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship ...

  10. Role of brainstem adenosine A1 receptors in the cardiovascular response to hypothalamic defence area stimulation in the anaesthetized rat.

    PubMed Central

    St Lambert, J. H.; Dashwood, M. R.; Spyer, K. M.

    1996-01-01

    1. The role of centrally located adenosine A1 receptors in the cardiovascular changes associated with the hypothalamic defence response has been investigated by in vitro autoradiography and the intraventricular application of an A1 receptor antagonist. 2. 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), a highly selective adenosine A1 antagonist and its vehicle, ethanol, were administered directly into the posterior portion of the fourth ventricle of alpha-chloralose anaesthetized, paralysed and artificially ventilated rats. 3. DPCPX (0.01 to 0.3 mg kg-1) caused a dose-dependent decrease in the magnitude of the evoked pressor response (from -13 to -23 mmHg) elicited on hypothalamic defence area stimulation at a dose 10 fold lower than that required to produce an equivalent effect following systemic administration whilst ethanol, the vehicle, had no effect. 4. In vitro autoradiography revealed a heterogeneous distribution of adenosine A1 binding sites in the lower brainstem of rats. Image analysis showed the ventrolateral medulla to have the highest density of A1 receptors. Intermediate levels of binding were seen in caudal regions of the nucleus tractus solitarii and the hypoglossal nucleus. 5. These data imply that a proportion of the cardiovascular response to hypothalamic defence area stimulation are produced by the activation of adenosine A1 receptors localized close to the surface of, or adjacent to, the fourth ventricle in the immediate vicinity of the injection site. PMID:8789379

  11. Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight

    NASA Technical Reports Server (NTRS)

    Baisch, F.; Beck, L.; Blomqvist, G.; Wolfram, G.; Drescher, J.; Rome, J. L.; Drummer, C.

    2000-01-01

    BACKGROUND: It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. METHODS: LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. RESULTS: Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. CONCLUSION: We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

  12. Effects of a gravity gradient on human cardiovascular responses

    NASA Technical Reports Server (NTRS)

    Hastreiter, D.; Young, L. R.

    1997-01-01

    Eight subjects participated in one control and three rotation trials on a short-arm centrifuge such that the Gz levels at the feet were 0.5, 1.0, and 1.5 G. Trials consisted of 30 minutes of supine rest, 1 hour of rotation (or in the control, 30 additional minutes of rest and 30 minutes of standing), and a final 30-minute rest period. Measurements of heart rate, calf impedance, calf volume, and blood pressure support the findings that the highest G level is similar to standing and that the lower G levels fail to produce significant effects.

  13. Cardiovascular activity in blood-injection-injury phobia during exposure: evidence for diphasic response patterns?

    PubMed

    Ritz, Thomas; Meuret, Alicia E; Simon, Erica

    2013-08-01

    Exposure to feared stimuli in blood-injection-injury (BII)-phobia is thought to elicit a diphasic response pattern, with an initial fight-flight-like cardiovascular activation followed by a marked deactivation and possible fainting (vasovagal syncope). However, studies have remained equivocal on the importance of such patterns. We therefore sought to determine the prevalence and clinical relevance of diphasic responses using criteria that require a true diphasic response to exceed cardiovascular activation of an emotional episode of a negative valence and to exceed deactivation of an emotionally neutral episode. Sixty BII-phobia participants and 20 healthy controls were exposed to surgery, anger and neutral films while measuring heart rate, blood pressure, respiratory pattern, and end-tidal partial pressure of carbon dioxide (as indicator of hyperventilation). Diphasic response patterns were observed in up to 20% of BII-phobia participants and 26.6% of healthy controls for individual cardiovascular parameters. BII-phobia participants with diphasic patterns across multiple parameters showed more fear of injections and blood draws, reported the strongest physical symptoms during the surgery film, and showed the strongest tendency to hyperventilate. Thus, although only a minority of individuals with BII phobia shows diphasic responses, their occurrence indicates significant distress. Respiratory training may add to the treatment of BII phobia patients that show diphasic response patterns. PMID:23747585

  14. Cardiovascular response to apneic immersion in cool and warm water

    NASA Technical Reports Server (NTRS)

    Folinsbee, L.

    1974-01-01

    The influence of prior exposure to cool water and the influence of lung volume on the responses to breath holding were examined. The bradycardia and vasoconstriction that occur during breath-hold diving in man are apparently the resultant of stimuli from apnea, relative expansion of the thorax, lung volume, esophageal pressure, face immersion, and thermal receptor stimulation. It is concluded that the bradycardia and vasoconstriction associated with breath holding during body immersion are not attenuated by a preexisting bradycardia and vasoconstriction due to cold.

  15. [Characteristics of the human cardiovascular system in the human diving response].

    PubMed

    Baranova, T I

    2004-01-01

    Comparative-evolutional research of diving response showed that mechanisms of its expression had much in common in humans and in animals. Firstly, it involves a reflex bradycardia, vasoconstriction of peripheral vessels, and blood flow centralization. But, unlike animals whose diving response has some typical species peculiarities, human diving response is rather diverse. Four types of cardiovascular system response to face submersion were revealed: over-reactive, reactive, paradoxical, and nonreactive. These types were chosen according to the bradycardia character. It is also supposed that the occurrence of individual maximal R--R-interval, while serving as a signal to apnea stopping, is among the reasons of apnea activity limitation. PMID:15143489

  16. Age alters the cardiovascular response to direct passive heating

    NASA Technical Reports Server (NTRS)

    Minson, C. T.; Wladkowski, S. L.; Cardell, A. F.; Pawelczyk, J. A.; Kenney, W. L.

    1998-01-01

    During direct passive heating in young men, a dramatic increase in skin blood flow is achieved by a rise in cardiac output (Qc) and redistribution of flow from the splanchnic and renal vascular beds. To examine the effect of age on these responses, seven young (Y; 23 +/- 1 yr) and seven older (O; 70 +/- 3 yr) men were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), Qc (by acetylene rebreathing), central venous pressure (via peripherally inserted central catheter), blood pressures (by brachial auscultation), skin blood flow (from increases in forearm blood flow by venous occlusion plethysmography), splanchnic blood flow (by indocyanine green clearance), renal blood flow (by p-aminohippurate clearance), and esophageal and mean skin temperatures. Qc was significantly lower in the older than in the young men (11.1 +/- 0.7 and 7.4 +/- 0.2 l/min in Y and O, respectively, at the limit of thermal tolerance; P < 0. 05), despite similar increases in esophageal and mean skin temperatures and time to reach the limit of thermal tolerance. A lower stroke volume (99 +/- 7 and 68 +/- 4 ml/beat in Y and O, respectively, P < 0.05), most likely due to an attenuated increase in inotropic function during heating, was the primary factor for the lower Qc observed in the older men. Increases in HR were similar in the young and older men; however, when expressed as a percentage of maximal HR, the older men relied on a greater proportion of their chronotropic reserve to obtain the same HR response (62 +/- 3 and 75 +/- 4% maximal HR in Y and O, respectively, P < 0.05). Furthermore, the older men redistributed less blood flow from the combined splanchnic and renal circulations at the limit of thermal tolerance (960 +/- 80 and 720 +/- 100 ml/min in Y and O, respectively, P < 0. 05). As a result of these combined attenuated responses, the older men had a significantly lower increase in total blood flow directed to

  17. Age alters the cardiovascular response to direct passive heating.

    PubMed

    Minson, C T; Wladkowski, S L; Cardell, A F; Pawelczyk, J A; Kenney, W L

    1998-04-01

    During direct passive heating in young men, a dramatic increase in skin blood flow is achieved by a rise in cardiac output (Qc) and redistribution of flow from the splanchnic and renal vascular beds. To examine the effect of age on these responses, seven young (Y; 23 +/- 1 yr) and seven older (O; 70 +/- 3 yr) men were passively heated with water-perfused suits to their individual limit of thermal tolerance. Measurements included heart rate (HR), Qc (by acetylene rebreathing), central venous pressure (via peripherally inserted central catheter), blood pressures (by brachial auscultation), skin blood flow (from increases in forearm blood flow by venous occlusion plethysmography), splanchnic blood flow (by indocyanine green clearance), renal blood flow (by p-aminohippurate clearance), and esophageal and mean skin temperatures. Qc was significantly lower in the older than in the young men (11.1 +/- 0.7 and 7.4 +/- 0.2 l/min in Y and O, respectively, at the limit of thermal tolerance; P < 0. 05), despite similar increases in esophageal and mean skin temperatures and time to reach the limit of thermal tolerance. A lower stroke volume (99 +/- 7 and 68 +/- 4 ml/beat in Y and O, respectively, P < 0.05), most likely due to an attenuated increase in inotropic function during heating, was the primary factor for the lower Qc observed in the older men. Increases in HR were similar in the young and older men; however, when expressed as a percentage of maximal HR, the older men relied on a greater proportion of their chronotropic reserve to obtain the same HR response (62 +/- 3 and 75 +/- 4% maximal HR in Y and O, respectively, P < 0.05). Furthermore, the older men redistributed less blood flow from the combined splanchnic and renal circulations at the limit of thermal tolerance (960 +/- 80 and 720 +/- 100 ml/min in Y and O, respectively, P < 0. 05). As a result of these combined attenuated responses, the older men had a significantly lower increase in total blood flow directed to

  18. Prinzmetal's angina:reflex cardiovascular response during episode of pain.

    PubMed Central

    Perez-Gomez, F; Martin de Dios, R; Rey, J; Garcia Aguado, A

    1979-01-01

    Previous angiographic studies have shown that coronary spasm occurs in association with the variant angina described by Prinzmetal, confirming his original hypothesis. In this work we recorded the heart rate changes and the incidence of arrhythmias during variant angina. The patients were divided into two groups: anterior, with electrocardiographic signs of anterior ischaemia, and inferior, with changes in the inferior leads. There was a significant increase of heart rate during pain in anterior myocardial ischaemia and a significant decrease when the ischaemia was inferior. The incidence of ectopic arrhythmias during pain was significantly greater in patients with anterior ischaemia, but there was a high incidence of atrioventricular block in patients with inferior ischaemia. We suggest that these findings can be explained by different responses of the automatic nervous system to anterior and inferior acute myocardial ischaemia. Images PMID:475938

  19. Social Support and Networks: Cardiovascular Responses Following Recall on Immigration Stress Among Chinese Americans

    PubMed Central

    Suchday, Sonia; Wylie-Rosett, Judith

    2014-01-01

    Social support has been shown to act as a buffer for cardiovascular responses to stress. However, little is known about how social support and networks are related to cardiovascular responses to immigration stress recall. The current study evaluated the impact of structural and functional support on cardiovascular reaction following immigrant stress recall provocation as well as the moderation effect of interdependent self-construal among first-generation Chinese immigrants. One hundred fifty Chinese immigrants were recruited in the New York Chinatown area. Participants completed questionnaires assessing their levels of social support and networks, and interdependent self-construal. Following adaptation, participants recalled a recent post-immigration stress-provoking situation. Cardiovascular measures were taken during adaptation, stressor task, and recovery period. Hierarchical multiple regression analysis was performed. Social network size and type, as well as perceived emotional support were positively predictive of systolic blood pressure (SBP) reactivity changes. Instrumental support seeking was a positive predictor of SBP and diastolic blood pressure (DBP) reactivity. The moderation effect between instrumental support seeking and interdependent self-construal were significantly predictive of DBP reactivity and recovery, suggesting that perceptions about themselves in relation to others is a crucial factor for determining whether support seeking is beneficial or not. Social support was not a direct buffer on cardiovascular responses to stress among Chinese immigrants. Chinese values of interdependence and collectivism may partly explain the disconfirming results. Still, when interdependent self-construal was taken into account, Chinese immigrants who had less interdependent self-construal, but solicited more instrumental support, had faster adaptation to stress over the long term. PMID:24288021

  20. Cardiovascular responses to active and passive cycling movements.

    PubMed

    Nóbrega, A C; Williamson, J W; Friedman, D B; Araújo, C G; Mitchell, J H

    1994-06-01

    Ten healthy subjects were evaluated at rest and at 5 min of unloaded active (AC) and passive (PC) cycling. Passive limb movements were accomplished using a tandem bicycle with a second rider performing the movements. We measured heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), oxygen uptake (VO2), rating of perceived exertion (RPE), and electrical activity (EMG) of lower limbs muscles. Values for stroke volume (SV) and peripheral vascular resistance (PVR) were calculated. EMG, RPE, and VO2 were higher during AC than during PC (P < 0.001). CO increased during both modes of cycling, but during AC it resulted from a HR acceleration (73 +/- 2 at rest to 82 +/- 2 beats.min-1 at 60 rpm; P < 0.001) with no change in SV whereas during PC, SV increased from rest (65 +/- 4 at rest to 71 +/- 3 ml at 60 rpm; P = 0.003) along with no change in HR. PVR remained constant during PC, but decreased by 13% during AC (P < 0.001) and MAP increased only during PC (93 +/- 2 at rest to 107 +/- 2 mm Hg at 60 rpm). These results supports the concept that central command determines the HR response to dynamic exercise. The increase in SV and consequently in MAP during PC was probably due to increased venous return and/or to muscle mechanoreceptor-evoked increased myocardial contractility. PMID:8052111

  1. Abnormal cardiovascular responses induced by localized high power microwave exposure

    SciTech Connect

    Lu, S.-T; Brown, D.O.; Johnson, C.E.; Mathur, S.P. ); Elson, E.C. )

    1992-05-01

    A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz and 16 Hz pulsemodulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in the neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power but not to the lower average power microwaves. Depression of pulse pressure, an indication of a decrease in stroke volume, and increased or decreased heart rate were noted in presence of whole-body hyperthermia. The cardiac output of those animals exposed to higher average power microwaves was considered to be below normal as hypothesized. Decreased cardiac output and normal mean arterial pressure resulted in an increase in the total peripheral resistance which was contrary to the anticipated thermal response of animals.

  2. Habitual alcohol consumption is associated with lower cardiovascular stress responses--a novel explanation for the known cardiovascular benefits of alcohol?

    PubMed

    Jones, Alexander; McMillan, Merlin R; Jones, Russell W; Kowalik, Grzegorz T; Steeden, Jennifer A; Pruessner, Jens C; Taylor, Andrew M; Deanfield, John E; Muthurangu, Vivek

    2013-07-01

    In contrast to heavy alcohol consumption, which is harmful, light to moderate drinking has been linked to reduced cardiovascular morbidity and mortality. Effects on lipid status or clotting do not fully explain these benefits. Exaggerated cardiovascular responses to mental stress are detrimental to cardiovascular health. We hypothesized that habitual alcohol consumption might reduce these responses, with potential benefits. Advanced magnetic resonance techniques were used to accurately measure cardiovascular responses to an acute mental stressor (Montreal Imaging Stress Task) in 88 healthy adults (∼1:1 male:female). Salivary cortisol and task performance measures were used to assess endocrine and cognitive responses. Habitual alcohol consumption and confounding factors were assessed by questionnaire. Alcohol consumption was inversely related to responses of heart rate (HR) (r = -0.31, p = 0.01), cardiac output (CO) (r = -0.32, p = 0.01), vascular resistance (r = 0.25, p = 0.04) and mean blood pressure (r = -0.31, p = 0.01) provoked by stress, but not to stroke volume (SV), or arterial compliance changes. However, high alcohol consumers had greater cortisol stress responses, compared to moderate consumers (3.5 versus 0.7 nmol/L, p = 0.04). Cognitive measures did not differ. Findings were not explained by variations in age, sex, social class, ethnicity, physical activity, adrenocortical activity, adiposity, smoking, menstrual phase and chronic stress. Habitual alcohol consumption is associated with reduced cardiac responsiveness during mental stress, which has been linked to lower risk of hypertension and vascular disease. Consistent with established evidence, our findings suggest a mechanism by which moderate alcohol consumption might reduce cardiovascular disease, but not high consumption, where effects such as greater cortisol stress responses may negate any benefits. PMID:23425242

  3. The role of neuropeptide Y in the ovine fetal cardiovascular response to reduced oxygenation

    PubMed Central

    Sanhueza, Emilia M; Johansen-Bibby, Anja A; Fletcher, Andrew J W; Riquelme, Raquel A; Daniels, Alejandro J; Serón-Ferré, Maria; Gaete, Cristián R; Carrasco, Jorge E; Llanos, Aníbal J; Giussani, Dino A

    2003-01-01

    This study investigated the role of neuropeptide Y (NPY) in mediating cardiovascular responses to reduced oxygenation in the late gestation ovine fetus by: (1) comparing the effects on the cardiovascular system of an exogenous infusion of NPY with those elicited by moderate or severe reductions in fetal oxygenation; and (2) determining the effect of fetal i.v. treatment with a selective NPY-Y1 receptor antagonist on the fetal cardiovascular responses to acute moderate hypoxaemia. Under general anaesthesia, 14 sheep fetuses (0.8–0.9 of gestation) were surgically prepared with vascular and amniotic catheters. In 5 of these fetuses, a Transonic flow probe was also implanted around a femoral artery. Following at least 5 days of recovery, one group of fetuses (n = 9) was subjected to a 30 min treatment period with exogenous NPY (17 μg kg−1 bolus plus 0.85 μg kg−1 min−1 infusion). In this group, fetal blood pressure and heart rate were monitored continuously and the distribution of the fetal combined ventricular output was assessed via injection of radiolabelled microspheres before and during treatment. The second group of fetuses instrumented with the femoral flow probe (n = 5) were subjected to a 3 h experiment consisting of 1 h of normoxia, 1 h of hypoxaemia, and 1 h of recovery during a slow i.v. infusion of vehicle. One or two days later, the acute hypoxaemia protocol was repeated during fetal i.v. treatment with a selective NPY-Y1 receptor antagonist (50 μg kg−1bolus + 1.5 μg kg−1 min−1 infusion). In these fetuses, fetal arterial blood pressure, heart rate and femoral vascular resistance were recorded continuously. The results show that fetal treatment with exogenous NPY mimics the fetal cardiovascular responses to asphyxia, and that treatment of the sheep fetus with a selective NPY-Y1 receptor antagonist does not affect the fetal cardiovascular response to acute moderate hypoxaemia. These results support a greater role for NPY in mediating the

  4. The role of neuropeptide Y in the ovine fetal cardiovascular response to reduced oxygenation.

    PubMed

    Sanhueza, Emilia M; Johansen-Bibby, Anja A; Fletcher, Andrew J W; Riquelme, Raquel A; Daniels, Alejandro J; Serón-Ferré, Maria; Gaete, Cristián R; Carrasco, Jorge E; Llanos, Aníbal J; Giussani, Dino A

    2003-02-01

    This study investigated the role of neuropeptide Y (NPY) in mediating cardiovascular responses to reduced oxygenation in the late gestation ovine fetus by: (1) comparing the effects on the cardiovascular system of an exogenous infusion of NPY with those elicited by moderate or severe reductions in fetal oxygenation; and (2) determining the effect of fetal I.V. treatment with a selective NPY-Y(1) receptor antagonist on the fetal cardiovascular responses to acute moderate hypoxaemia. Under general anaesthesia, 14 sheep fetuses (0.8-0.9 of gestation) were surgically prepared with vascular and amniotic catheters. In 5 of these fetuses, a Transonic flow probe was also implanted around a femoral artery. Following at least 5 days of recovery, one group of fetuses (n = 9) was subjected to a 30 min treatment period with exogenous NPY (17 microg kg(-1) bolus plus 0.85 microg kg(-1) min(-1) infusion). In this group, fetal blood pressure and heart rate were monitored continuously and the distribution of the fetal combined ventricular output was assessed via injection of radiolabelled microspheres before and during treatment. The second group of fetuses instrumented with the femoral flow probe (n = 5) were subjected to a 3 h experiment consisting of 1 h of normoxia, 1 h of hypoxaemia, and 1 h of recovery during a slow I.V. infusion of vehicle. One or two days later, the acute hypoxaemia protocol was repeated during fetal I.V. treatment with a selective NPY-Y(1) receptor antagonist (50 microg kg(-1) bolus + 1.5 microg kg(-1) min(-1) infusion). In these fetuses, fetal arterial blood pressure, heart rate and femoral vascular resistance were recorded continuously. The results show that fetal treatment with exogenous NPY mimics the fetal cardiovascular responses to asphyxia, and that treatment of the sheep fetus with a selective NPY-Y(1) receptor antagonist does not affect the fetal cardiovascular response to acute moderate hypoxaemia. These results support a greater role for NPY in

  5. Mind over Matter: Reappraising Arousal Improves Cardiovascular and Cognitive Responses to Stress

    PubMed Central

    Jamieson, Jeremy P.; Nock, Matthew K.; Mendes, Wendy Berry

    2012-01-01

    Researchers have theorized that changing the way we think about our bodily responses can improve our physiological and cognitive reactions to stressful events. However, the underlying processes through which mental states improve downstream outcomes are not well-understood. To this end, we examined whether reappraising stress-induced arousal could improve cardiovascular outcomes and decrease attentional bias for emotionally-negative information. Participants were randomly assigned to either a reappraisal condition in which they were instructed to think about their physiological arousal during a stressful task as functional and adaptive, or to one of two control conditions: attention reorientation and no instructions. Relative to controls, participants instructed to reappraise their arousal exhibited more adaptive cardiovascular stress responses – increased cardiac efficiency and lower vascular resistance – and decreased attentional bias. Thus, reappraising arousal shows physiological and cognitive benefits. Implications for health and potential clinical applications are discussed. PMID:21942377

  6. Computational Models of the Cardiovascular System and Its Response to Microgravity

    NASA Technical Reports Server (NTRS)

    Kamm, Roger D.

    1999-01-01

    Computational models of the cardiovascular system are powerful adjuncts to ground-based and in-flight experiments. We will provide NSBRI with a model capable of simulating the short-term effects of gravity on cardiovascular function. The model from this project will: (1) provide a rational framework which quantitatively defines interactions among complex cardiovascular parameters and which supports the critical interpretation of experimental results and testing of hypotheses. (2) permit predictions of the impact of specific countermeasures in the context of various hypothetical cardiovascular abnormalities induced by microgravity. Major progress has been made during the first 18 months of the program: (1) We have developed an operational first-order computer model capable of simulating the cardiovascular response to orthostatic stress. The model consists of a lumped parameter hemodynamic model and a complete reflex control system. The latter includes cardiopulmonary and carotid sinus reflex limbs and interactions between the two. (2) We have modeled the physiologic stress of tilt table experiments and lower body negative pressure procedures (LBNP). We have verified our model's predictions by comparing them with experimental findings from the literature. (3) We have established collaborative efforts with leading investigators interested in experimental studies of orthostatic intolerance, cardiovascular control, and physiologic responses to space flight. (4) We have established a standardized method of transferring data to our laboratory from the ongoing NSBRI bedrest studies. We use this data to estimate input parameters to our model and compare our model predictions to actual data to further verify our model. (5) We are in the process of systematically simulating current hypotheses concerning the mechanism underlying orthostatic intolerance by matching our simulations to stand test data from astronauts pre- and post-flight. (6) We are in the process of developing a

  7. The energetic and cardiovascular response to treadmill walking and cycle ergometer exercise in obese women.

    PubMed

    Lafortuna, Claudio L; Agosti, Fiorenza; Galli, Raffaela; Busti, Carlo; Lazzer, Stefano; Sartorio, Alessandro

    2008-08-01

    Physical activity is essential in obesity management, but exercise capacity is compromised in obese individuals due to the excessive body mass, impacting on body movement's energetics, and to the dysfunctions of regulatory mechanisms, affecting cardiovascular responses. This study aims to compare the energetics and cardiovascular responses of walking and cycling in obese women, and to formulate recommendations regarding the most suitable type of exercise for obesity. Fifteen obese (OB) and six normal weight (NW) women exercised on treadmill (TM) and cycle ergometer (CE). During both exercise modalities, metabolic rate was higher in OB than in NW and correlated with measures of body mass. Leg movement metabolic rate during cycling depended upon individual adiposity, and when accounted for, mechanical efficiency was similar in the two groups. When accounting for extra mass, differences in metabolic rate among groups are abolished for CE, indicating no obesity impairment of muscle efficiency, but not for TM, suggesting that differences in biomechanics may explain the higher net cost of transport of OB. In both groups, HR was higher during CE than TM at the same oxygen uptake (VO(2)), but in OB the HR increment over VO(2) was greater for CE than for TM. Therefore, due to different cardiovascular responses to TM and CE in OB, walking is more convenient, enabling OB to attain target energy expenditure at lower HR or in a shorter time. PMID:18496708

  8. Success importance and urge magnitude as determinants of cardiovascular response to a behavioral restraint challenge.

    PubMed

    Agtarap, Stephanie D; Wright, Rex A; Mlynski, Christopher; Hammad, Rawan; Blackledge, Sabrina

    2016-04-01

    Decades of research have investigated a conceptual analysis concerned with determinants and cardiovascular correlates of effort in people confronted with performance challenges, that is, opportunities to alter some course of events by acting. One suggestion is that effort and associated cardiovascular responses should be determined jointly by the difficulty of meeting a challenge and the importance of doing so. The present experiment tested this in a context involving behavioral restraint, that is, effortful resistance against a behavioral impulse or urge. Participants were presented a mildly evocative violent film clip (restraint difficulty low) or a strongly evocative violent film clip (restraint difficulty high) with instructions to refrain from showing any facial response. Success was made more or less important through coordinated manipulations of outcome expectancy, ego-involvement and social evaluation. As expected, SBP responses assessed during the work period were proportional to clip evocativeness - i.e., the difficulty of the restraint challenge - when importance was high, but low regardless of clip evocativeness when importance was low. Findings conceptually replicate previous cardiovascular results and support extension of the guiding analysis to the behavioral restraint realm. PMID:26968495

  9. Identification of vascular responses to exercise and orthostatic stress in bed rest-induced cardiovascular deconditioning.

    PubMed

    Aletti, Federico; Ferrario, Manuela; Tam, Enrico; Cautero, Michela; Cerutti, Sergio; Capelli, Carlo; Baselli, Giuseppe

    2009-01-01

    In this paper, the effects of bed rest-induced cardiovascular deconditioning were investigated by means of a previously developed multivariate model for the assessment of arterial control of circulation. The vascular response to exercise and tilt, before and after a 14-day head down tilt bed rest, was identified and disentangled from the main mechanisms due to global, neural control of circulation. Results of the decomposition of diastolic pressure and pulse pressure beat-by-beat series and the relevant spectral analysis suggested that the autoregulation-related response is not affected by prolonged exposition to microgravity. As to the complex regulation of arterial blood pressure, a maintained responsiveness to sympathetic stimuli was found, even in presence of indications of the cardiovascular deconditioning, such as tachycardia, reset of baroreflex, cardiopulmonary unloading. These preliminary results emphasized the necessity for more complex analyses of the main alterations and compensatory mechanisms elicited by microgravity-induced-cardiovascular deconditioning, in order to develop more effective long term strategies to prevent it. PMID:19963898

  10. Dose-and time-dependent cardiovascular responses induced by ethanol

    SciTech Connect

    Brackett, D.J.; Gauvin, D.V.; Lerner, M.R.; Lander, T.J.; Holloway, F.A.; Wilson, M.F. )

    1991-03-11

    A literature survey has revealed that a dose-response relationship between ethanol (ETOH) and serial measurements of cardiovascular parameters that include cardiac output (CO) and systemic vascular resistance (SVR) has not been established in conscious animals. The available literature in this area is controversial regarding the responses of these two parameters that control tissue blood flow. In this study, rats were instrumented for conscious cardiovascular measurements and blood sampling. Rats were monitored for 4 hrs after intragastric ETOH at 2, 4, or 6 g/kg or water. Samples for blood alcohol concentrations were taken at every measurement point and achieved peak concentrations of 63 {plus minus} 4, 103 {plus minus} 6, and 221 {plus minus} 17 mg/dl. Dose- and time-dependency were documented for decreased CO, blood pressure, respiration rate, stroke volume, and central venous pressure, and increased SVR, heart rate, and blood glucose concentrations. Thermoregulatory disturbances were observed at all doses. Blood hematocrit and lactate concentrations were unchanged. In conscious rats ethanol induced significant dose- and time-dependent hemodynamic alterations, including marked CO reduction and peripheral vasoconstriction, suggesting the potential of compromised tissue perfusion. Data also indicate that increased sympathoadrenal activity following ETOH administration may be a significant mediator of these responses. These data suggest: (1) when evaluating the physiological effects of drugs, a complete battery of cardiovascular and physiological measurements need to be assessed, and (2) when measured, these indices suggest a greater degree of compromise by ETOH than previously reported.

  11. Here we go again: bullying history and cardiovascular responses to social exclusion.

    PubMed

    Newman, Matthew L

    2014-06-22

    Previous research suggests that social exclusion-both acute and chronic-may be associated with a pattern of blunted cardiovascular responding. But it is unknown to what extent acute and chronic exclusion interact. That is, what happens when victims of long-term social rejection encounter an instance of exclusion later in life? The goal of the present study was to test whether prior experience being bullied would alter cardiovascular responses to an acute experience of social exclusion. Participants took part in a short online chat, during which they were either included or excluded from the conversation. Consistent with hypotheses, all participants showed an increase in sympathetic activity in the exclusion condition, but this response was significantly blunted among those with more chronic history of bullying victimization. No differences were observed for parasympathetic activity. This pattern suggests that a history of chronic victimization magnifies the cardiovascular "blunting" shown previously among victims of ostracism. This line of work suggests that bullying victims may develop regulatory mechanisms in response to social threats, and this may ultimately provide valuable information for helping victims become more resilient. PMID:24858188

  12. High-Velocity Resistance Exercise Protocols in Older Women: Effects on Cardiovascular Response

    PubMed Central

    da Silva, Rodrigo P.; Novaes, Jefferson; Oliveira, Ricardo J.; Gentil, Paulo; Wagner, Dale; Bottaro, Martim

    2007-01-01

    Acute cardiovascular responses to different high-velocity resistance exercise protocols were compared in untrained older women. Twelve apparently healthy volunteers (62.6 ± 2.9 y) performed three different protocols in the bench press (BP). All protocols involved three sets of 10 repetitions performed with a 10RM load and 2 minutes of rest between sets. The continuous protocol (CP) involved ten repetitions with no pause between repetitions. The discontinuous protocols were performed with a pause of five (DP5) or 15 (DP15) seconds between the fifth and sixth repetitions. Heart rate (HR), systolic blood pressure (SBP), rate pressure product (RPP), Rating of Perceived Exertion (RPE), and blood lactate (BLa) were assessed at baseline and at the end of all exercise sets. Factorial ANOVA was used to compare the cardiovascular response among different protocols. Compared to baseline, HR and RPP were significantly (p < 0.05) higher after the third set in all protocols. HR and RPP were significantly (p < 0.05) lower in DP5 and DP15 compared with CP for the BP exercise. Compared to baseline, RPE increased significantly (p < 0.05) with each subsequent set in all protocols. Blood lactate concentration during DP5 and DP15 was significantly lower than CP. It appears that discontinuous high-velocity resistance exercise has a lower cardiovascular demand than continuous resistance exercise in older women. Key pointsThe assessment of cardiovascular responses to high-velocity resistance exercise in older individuals is very important for exercise prescription and rehabilitation in elderly population.Discontinuous protocol decrease myocardial oxygen consumption (HR x SBP) during the performance of dynamic high-velocity resistance exercise in older women.The decrease in RPP (~ 8.5%) during the discontinuous protocol has clinical implications when developing high-velocity resistance exercise strategies for elderly individuals. PMID:24149492

  13. Network-based association of hypoxia-responsive genes with cardiovascular diseases

    NASA Astrophysics Data System (ADS)

    Wang, Rui-Sheng; Oldham, William M.; Loscalzo, Joseph

    2014-10-01

    Molecular oxygen is indispensable for cellular viability and function. Hypoxia is a stress condition in which oxygen demand exceeds supply. Low cellular oxygen content induces a number of molecular changes to activate regulatory pathways responsible for increasing the oxygen supply and optimizing cellular metabolism under limited oxygen conditions. Hypoxia plays critical roles in the pathobiology of many diseases, such as cancer, heart failure, myocardial ischemia, stroke, and chronic lung diseases. Although the complicated associations between hypoxia and cardiovascular (and cerebrovascular) diseases (CVD) have been recognized for some time, there are few studies that investigate their biological link from a systems biology perspective. In this study, we integrate hypoxia genes, CVD genes, and the human protein interactome in order to explore the relationship between hypoxia and cardiovascular diseases at a systems level. We show that hypoxia genes are much closer to CVD genes in the human protein interactome than that expected by chance. We also find that hypoxia genes play significant bridging roles in connecting different cardiovascular diseases. We construct a hypoxia-CVD bipartite network and find several interesting hypoxia-CVD modules with significant gene ontology similarity. Finally, we show that hypoxia genes tend to have more CVD interactors in the human interactome than in random networks of matching topology. Based on these observations, we can predict novel genes that may be associated with CVD. This network-based association study gives us a broad view of the relationships between hypoxia and cardiovascular diseases and provides new insights into the role of hypoxia in cardiovascular biology.

  14. Exposure to Maternal Gestational Diabetes Is Associated With Higher Cardiovascular Responses to Stress in Adolescent Indians

    PubMed Central

    Veena, Sargoor R.; Jones, Alexander; Srinivasan, Krishnamachari; Osmond, Clive; Karat, Samuel C.; Kurpad, Anura V.; Fall, Caroline H. D.

    2015-01-01

    Context: Altered endocrinal and autonomic nervous system responses to stress may link impaired intra-uterine growth with later cardiovascular disease. Objective: To test the hypothesis that offspring of gestational diabetic mothers (OGDM) have high cortisol and cardiosympathetic responses during the Trier Social Stress Test for Children (TSST-C). Design: Adolescents from a birth cohort in India (n = 213; mean age, 13.5 y), including 26 OGDM, 22 offspring of diabetic fathers (ODF), and 165 offspring of nondiabetic parents (controls) completed 5 minutes each of public speaking and mental arithmetic tasks in front of two unfamiliar “evaluators” (TSST-C). Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Heart rate, blood pressure (BP), stroke volume, cardiac output, and total peripheral resistance were measured continuously at baseline, during the TSST-C, and for 10 minutes after the test using a finger cuff; the beat-to-beat values were averaged for these periods. Results: Cortisol and cardiosympathetic parameters increased from baseline during stress (P < .001). OGDM had greater systolic BP (mean difference, 5.6 mm Hg), cardiac output (0.5 L/min), and stroke volume (4.0 mL) increases and a lower total peripheral resistance rise (125 dyn · s/cm5) than controls during stress. ODF had greater systolic BP responses than controls (difference, 4.1 mm Hg); there was no difference in other cardiosympathetic parameters. Cortisol responses were similar in all three groups. Conclusions: Maternal diabetes during pregnancy is associated with higher cardiosympathetic stress responses in the offspring, which may contribute to their higher cardiovascular disease risk. Further research may confirm stress-response programming as a predictor of cardiovascular risk in OGDM. PMID:25478935

  15. Spaceflight Did Not Impair Cardiovascular Responses to Upright Posture in an Elderly Astronaut

    NASA Technical Reports Server (NTRS)

    Rossum, Alfred C.; Ziegler, Michael G.; Meck, Janice V.

    2001-01-01

    Some of the cardiovascular changes associated with spaceflight have similarities to those associated with aging. We studied the neuroendocrine and hemodynamic responses to upright posture in a 77 year old astronaut before and after spaceflight and compared them to those of a group of 20 younger (41 plus or minus 1 years) astronauts. While arterial pressure responses to standing were similar between the young and old astronauts, hemodynamic profiles were quite different. The elderly astronaut achieved adequate standing arterial pressure primarily by maintaining stroke volume and thus cardiac output. In spite of very high norepinephrine release, he had very little increase in heart rate or total peripheral resistance. This pattern persisted on all test occasions. These responses suggest high sympathetic responses, down-regulated adrenergic receptors and decreased venous compliance typical of aging. In contrast, younger astronauts did not maintain stroke volume or cardiac output with standing, but had significant increases in heart rate and resistance. These results suggest that this elderly subject had cardiovascular responses to standing that are expected in an aged person. These responses were not deleteriously affected by spaceflight. We suggest that healthy, fit elderly individuals are able to withstand the stresses of extreme environments and are not necessarily limited in their activities simply due to their chronological age.

  16. Adiposity is associated with blunted cardiovascular, neuroendocrine and cognitive responses to acute mental stress.

    PubMed

    Jones, Alexander; McMillan, Merlin R; Jones, Russell W; Kowalik, Grzegorz T; Steeden, Jennifer A; Deanfield, John E; Pruessner, Jens C; Taylor, Andrew M; Muthurangu, Vivek

    2012-01-01

    Obesity and mental stress are potent risk factors for cardiovascular disease but their relationship with each other is unclear. Resilience to stress may differ according to adiposity. Early studies that addressed this are difficult to interpret due to conflicting findings and limited methods. Recent advances in assessment of cardiovascular stress responses and of fat distribution allow accurate assessment of associations between adiposity and stress responsiveness. We measured responses to the Montreal Imaging Stress Task in healthy men (N = 43) and women (N = 45) with a wide range of BMIs. Heart rate (HR) and blood pressure (BP) measures were used with novel magnetic resonance measures of stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR) and arterial compliance to assess cardiovascular responses. Salivary cortisol and the number and speed of answers to mathematics problems in the task were used to assess neuroendocrine and cognitive responses, respectively. Visceral and subcutaneous fat was measured using T(2) (*)-IDEAL. Greater BMI was associated with generalised blunting of cardiovascular (HR:β = -0.50 bpm x unit(-1), P = 0.009; SV:β = -0.33 mL x unit(-1), P = 0.01; CO:β = -61 mL x min(-1) x unit(-1), P = 0.002; systolic BP:β = -0.41 mmHg x unit(-1), P = 0.01; TPR:β = 0.11 WU x unit(-1), P = 0.02), cognitive (correct answers: r = -0.28, P = 0.01; time to answer: r = 0.26, P = 0.02) and endocrine responses (cortisol: r = -0.25, P = 0.04) to stress. These associations were largely determined by visceral adiposity except for those related to cognitive performance, which were determined by both visceral and subcutaneous adiposity. Our findings suggest that adiposity is associated with centrally reduced stress responsiveness. Although this may mitigate some long-term health risks of stress responsiveness, reduced performance under stress may be a more immediate

  17. Amygdalar neuronal activity mediates the cardiovascular responses evoked from the dorsolateral periaqueductal gray in conscious rats.

    PubMed

    de Abreu, A R; Abreu, A R; Santos, L T; de Souza, A A; da Silva, L G; Chianca, D A; de Menezes, R C

    2015-01-22

    There is ample evidence that both lateral/dorsolateral periaqueductal gray (l/dlPAG) and basolateral amygdala (BLA) are essential for the regulation of the autonomic responses evoked during innate reactions to threatening stimuli. However, it is not well established to what extent the BLA regulates the upstream functional connection from the l/dlPAG. Here we evaluated the role of the BLA and its glutamatergic receptors in the cardiovascular responses induced by l/dlPAG stimulation in rats. We examined the influence of acute inhibition of the BLA, unilaterally, by injecting muscimol on the cardiovascular responses evoked by the injection of N-methyl D-aspartate (NMDA) into the l/dlPAG. We also evaluated the role of BLA ionotropic glutamate receptors in these responses by injecting antagonists of NMDA and AMPA/kainate receptor subtypes into the BLA. Our results show that the microinjection of NMDA in the BLA increased the mean arterial pressure (MAP) and heart rate (HR). Injection of NMDA into the l/dlPAG caused similar increases in these variables, which was prevented by the prior injection of muscimol, a GABAA agonist, into the BLA. Moreover, injection of glutamatergic antagonists (2-amino-5-phosphonopentanoate (AP5) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)) into the BLA reduced the increase in MAP and HR induced by l/dlPAG activation. Finally, the inhibition of the central amygdala neurons failed to reduce the cardiovascular changes induced by l/dlPAG activation. These results indicate that physiological responses elicited by l/dlPAG activation require the neuronal activity in the BLA. This ascending excitatory pathway from the l/dlPAG to the BLA might ensure the expression of the autonomic component of the defense reaction. PMID:25451289

  18. Effect of an extruded pea or rice diet on postprandial insulin and cardiovascular responses in dogs.

    PubMed

    Adolphe, J L; Drew, M D; Silver, T I; Fouhse, J; Childs, H; Weber, L P

    2015-08-01

    Peas are increasing in popularity as a source of carbohydrate, protein and fibre in extruded canine diets. The aim of this study was to test the health effects of two canine diets with identical macronutrient profiles, but containing either yellow field peas or white rice as the carbohydrate source on metabolism, cardiovascular outcomes and adiposity. First, the acute glycemic, insulinemic and cardiovascular responses to the pea- or rice-based diets were determined in normal weight beagles (n = 7 dogs). The glycemic index did not differ between the pea diet (56 ± 12) and rice diet (63 ± 9). Next, obese beagles (n = 9) were fed the yellow field pea diet or white rice diet ad libitum for 12 weeks in a crossover study. Adiposity (measured using computed tomography), metabolic (oral glucose tolerance test, plasma leptin, adiponectin, C-reactive protein) and cardiovascular assessments (echocardiography and blood pressure) were performed before and after each crossover study period. After 12 weeks on each diet, peak insulin (p = 0.05) and area under the curve (AUC) for insulin after a 10 g oral glucose tolerance test (p = 0.05) were lower with the pea than the rice diet. Diet did not show a significant effect on body weight, fat distribution, cardiovascular variables, adiponectin or leptin. In conclusion, a diet containing yellow field peas reduced the postprandial insulin response after glucose challenge in dogs despite continued obesity, indicating improved metabolic health. PMID:25475789

  19. Coconut fragrance and cardiovascular response to laboratory stress: results of pilot testing.

    PubMed

    Mezzacappa, Elizabeth Sibolboro; Arumugam, Uma; Chen, Sylvia Yue; Stein, Traci R; Oz, Mehmet; Buckle, Jane

    2010-01-01

    There is preliminary evidence that pleasant fragrances may alter response to stressors in different settings. This pilot study examined the effect of coconut fragrance on cardiovascular response to standard laboratory stressors. While inhaling coconut fragrance (n = 17) or air (n = 15), subjects performed a Stroop color-word task and a mental arithmetic task. Heart rate (HR), heart period variability (HPV) and blood pressure were measured during the 5-minute baseline, the task, and the recovery periods. The results indicated that subjects breathing coconut fragrance had higher HR and lower HPV than those who performed tasks while breathing air. HR response to mental arithmetic seemed to be blunted in the subjects breathing coconut; however, the lack of a difference in HPV seems to indicate that the blunting may be due to decreased sympathetic response, not decreased parasympathetic withdrawal under stress. Blood pressure recovery was slightly enhanced in subjects under coconut fragrance. Thus, the results of this pilot test suggest that coconut fragrance may alter cardiovascular activity both at rest and in response to stressors. Future experimentation should attempt to replicate and extend these findings in larger samples in clinical settings. PMID:21037456

  20. Melatonin and Other Tryptophan Metabolites Produced by Yeasts: Implications in Cardiovascular and Neurodegenerative Diseases

    PubMed Central

    Hornedo-Ortega, Ruth; Cerezo, Ana B.; Troncoso, Ana M.; Garcia-Parrilla, M. Carmen; Mas, Albert

    2016-01-01

    Yeast metabolism produces compounds derived from tryptophan, which are found in fermented beverages, such as wine and beer. In particular, melatonin and serotonin, may be relevant due to their bioactivity in humans. Indeed, the former is a neurohormone related to circadian rhythms, which also has a putative protective effect against degenerative diseases. Moreover, serotonin is a neurotransmitter itself, in addition to being a precursor of melatonin synthesis. This paper summarizes data reported on fermented beverages, to evaluate dietary intake. Additionally, the article reviews observed effects of yeast amino acid metabolites on the prevention of neurodegenerative diseases (Alzheimer’s and Parkinson’s) and angiogenesis, focusing on evidence of the molecular mechanism involved and identification of molecular targets. PMID:26834716

  1. Females have a blunted cardiovascular response to one year of intensive supervised endurance training.

    PubMed

    Howden, Erin J; Perhonen, Merja; Peshock, Ronald M; Zhang, Rong; Arbab-Zadeh, Armin; Adams-Huet, Beverley; Levine, Benjamin D

    2015-07-01

    Cross-sectional studies in athletes suggest that endurance training augments cardiovascular structure and function with apparently different phenotypes in athletic males and females. It is unclear whether the longitudinal response to endurance training leads to similar cardiovascular adaptations between sexes. We sought to determine whether males and females demonstrate similar cardiovascular adaptations to 1 yr of endurance training, matched for training volume and intensity. Twelve previously sedentary males (26 ± 7, n = 7) and females (31 ± 6, n = 5) completed 1 yr of progressive endurance training. All participants underwent a battery of tests every 3 mo to determine maximal oxygen uptake (V̇o2max) and left ventricle (LV) function and morphology (cardiac magnetic resonance imaging). Pulmonary artery catheterization was performed before and after 1 yr of training, and pressure-volume and Starling curves were constructed during decreases (lower-body negative pressure) and increases (saline infusion) in cardiac volume. Males progressively increased V̇o2max, LV mass, and mean wall thickness, before reaching a plateau from month 9 to 12 of training. In contrast, despite exactly the same training, the response in females was markedly blunted, with V̇o2max, LV mass, and mean wall thickness plateauing after only 3 mo of training. The response of LV end-diastolic volume was not influenced by sex (males +20% and females +18%). After training Starling curves were shifted upward and left, but the effect was greatest in males (interaction P = 0.06). We demonstrate for the first time clear sex differences in response to 1 yr of matched endurance training, such that the development of ventricular hypertrophy and increase in V̇o2max in females is markedly blunted compared with males. PMID:25930024

  2. Rat Cardiovascular Responses to Whole Body Suspension: Head-down and Non-Head-Down Tilt

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, Joseph M.; Dombrowski, Judy

    1992-01-01

    The rat whole body suspension technique mimics responses seen during exposure to microgravity and was evaluated as a model for cardiovascular responses with two series of experiments. In one series, changes were monitored in chronically catheterized rats during 7 days of Head-Down Tilt (HDT) or Non-Head-Down Tilt (N-HDT) and after several hours of recovery. Elevations of mean arterial (MAP), systolic, and diastolic pressures of approx. 20 % (P less than 0.05) in HDT rats began as early as day 1 and were maintained for the duration of suspension. Pulse pressures were relatively unaffected, but heart rates were elevated approx. 10 %. During postsuspension (2-7 h), most cardiovascular parameters returned to presuspension levels. N-HDT rats exhibited elevations chiefly on days 3 and 7. In the second series, blood pressure was monitored in 1- and 3-day HDT and N-HDT rats to evaluate responses to rapid head-up tilt. MAP, systolic and diastolic pressures, and HR were elevated (P less than 0.05) in HDT and N-HDT rats during head-up tilt after 1 day of suspension, while pulse pressures remained un changed. HDT rats exhibited elevated pretilt MAP and failed to respond to rapid head-up tilt with further increase of MAP on day 3, indicating some degree of deconditioning. The whole body suspended rat may be useful as a model to better understand responses of rats exposed to microgravity.

  3. Cardiovascular responses to postural changes: differences with age for women and men

    NASA Technical Reports Server (NTRS)

    Frey, M. A.; Tomaselli, C. M.; Hoffler, W. G.

    1994-01-01

    The cardiovascular responses to postural change, and how they are affected by aging, are inadequately described in women. Therefore, the authors examined the influence of age and sex on the responses of blood pressure, cardiac output, heart rate, and other variables to change in posture. Measurements were made after 10 minutes each in the supine, seated, and standing positions in 22 men and 25 women who ranged in age from 21 to 59 years. Several variables differed, both by sex and by age, when subjects were supine. On rising, subjects' diastolic and mean arterial pressures, heart rate, total peripheral resistance (TPR), and thoracic impedance increased; cardiac output, stroke volume, and mean stroke ejection rate decreased; and changes in all variables, except heart rate, were greater from supine to sitting than sitting to standing. The increase in heart rate was greater in the younger subjects, and increases in TPR and thoracic impedance were greater in the older subjects. Stroke volume decreased less, and TPR and thoracic impedance increased more, in the women than in the men. The increase in TPR was particularly pronounced in the older women. These studies show that the cardiovascular responses to standing differ, in some respects, between the sexes and with age. The authors suggest that the sex differences are, in part, related to greater decrease of thoracic blood volume with standing in women than in men, and that the age differences result, in part, from decreased responsiveness of the high-pressure baroreceptor system.

  4. Afferent and efferent components of the cardiovascular reflex responses to acute hypoxia in term fetal sheep.

    PubMed Central

    Giussani, D A; Spencer, J A; Moore, P J; Bennet, L; Hanson, M A

    1993-01-01

    1. We studied the effects of acute isocapnic hypoxia on arterial and central venous pressures, carotid and femoral blood flows and heart rate in intact and carotid denervated fetal sheep between 118 and 125 days gestation, after pre-treatment with either saline, atropine or phentolamine. Electrocortical activity (ECoG) and the incidence of fetal breathing movements (FBM) were also compared between intact and carotid denervated fetuses. 2. There were no significant differences between intact and denervated fetuses in any variable measured during normoxia. Soon after the onset of hypoxia a marked bradycardia occurred in intact, but not in denervated fetuses. Femoral blood flow and femoral vascular resistance (perfusion pressure/femoral blood flow) increased in intact, but not in denervated fetuses. Carotid blood flow increased in both groups of fetuses during hypoxia, but carotid vascular resistance did not change. During hypoxia, the incidence of FBM and low-voltage ECoG was similarly reduced in both groups of fetuses. 3. Atropine produced a rise in fetal heart rate during the control period in intact but not in denervated fetuses. At the onset of hypoxia atropine prevented the initial bradycardia seen in intact fetuses. In denervated fetuses a further increase in heart rate occurred throughout the hypoxia. 4. All denervated fetuses treated with phentolamine died during the hypoxic challenge, but nine out of fourteen intact fetuses treated with phentolamine survived. 5. In intact fetuses which survived hypoxia after treatment with phentolamine, the increase in arterial blood pressure was smaller and the increase in femoral resistance did not occur. In these fetuses a rise in heart rate occurred in hypoxia. Carotid vascular resistance decreased during hypoxia after administration of phentolamine. 6. Our results indicate that the initial cardiovascular responses of the late gestation sheep fetus to hypoxia are reflex, and that the carotid chemoreceptors provide the

  5. Produced water exposure alters bacterial response to biocides.

    PubMed

    Vikram, Amit; Lipus, Daniel; Bibby, Kyle

    2014-11-01

    Microbial activity during the holding and reuse of wastewater from hydraulic fracturing operations, termed produced water, may lead to issues with corrosion, sulfide release, and fouling. Biocides are applied to control biological activity, often with limited efficacy, which is typically attributed to chemical interactions with the produced water. However, it is unknown whether there is a biologically driven mechanism to biocide tolerance in produced water. Here, we demonstrate that produced water exposure results in an enhanced tolerance against the typically used biocide glutaraldehyde and increased susceptibility to the oxidative biocide hypochlorite in a native and a model bacteria and that this altered resistance is due to the salinity of the produced water. In addition, we elucidate the genetic response of the model organism Pseudomonas fluorescens to produced water exposure to provide a mechanistic interpretation of the altered biocide resistance. The RNA-seq data demonstrated the induction of genes involved in osmotic stress, energy production and conversion, membrane integrity, and protein transport following produced water exposure, which facilitates bacterial survival and alters biocide tolerance. Efforts to fundamentally understand biocide resistance mechanisms, which enable the optimization of biocide application, hold significant implications for greening of the fracturing process through encouraging produced water recycling. Specifically, these results suggest the necessity of optimizing biocide application at the level of individual shale plays, rather than historical experience, based upon produced water characteristics and salinity. PMID:25279933

  6. Cardiovascular Response to Manual Acupuncture Needle Stimulation among Apparently Healthy Nigerian Adults.

    PubMed

    Sokunbi, Ganiyu; Maduagwu, Stanley; Jaiyeola, Olabode; Gambo, Hassan; Blasu, Cephas

    2016-06-01

    This study investigated experience with acupuncture needle stimulation of apparently healthy adult Nigerians and the responses of the systolic blood pressure (SBP), diastolic blood pressure, heart rate (HR), and rate pressure products (RPP) to acupuncture at both real acupuncture points relevant to the treatment of cardiovascular disorder and sham acupuncture points not relevant to the treatment of cardiovascular disorder. Seventy-eight participants were randomly placed into three groups: the real acupuncture group (RAG); the sham acupuncture group (SAG); and the control group, with 26 participants per group. Data were collected preintervention, 15 minutes into acupuncture stimulation, postintervention, and 15 minutes after intervention. Changes (postintervention - preintervention scores) in the SBP, HR, and RPP were statistically lower in the RAG than in the SAG. Changes in the DBP showed a significant difference between the SAG and the RAG (p > 0.05). Findings from this study showed that among apparently healthy Nigerian adults, acupuncture needle stimulation at acupoints relevant to cardiovascular disorders was more effective than sham intervention in reducing the SBP, HR, and RPP. Participants reported heaviness, numbness, and increasing pain, but no dizziness, fainting and/or life-threatening side effects, during and after the acupuncture needle stimulation. PMID:27342888

  7. Cardiovascular responses to static exercise in conscious cats: effects of intracerebroventricular injection of clonidine.

    PubMed

    Ally, A; Hand, G A; Mitchell, J H

    1996-03-01

    1. Static exercise elicits increases in arterial blood pressure and heart rate (HR) in humans and conscious animals. In this study, the effects of intracerebroventricular (I.C.V.) administration of clonidine, an alpha 2-adrenergic agonist, on these cardiovascular responses were investigated using conscious cats. Four cats were operantly trained to extend a forelimb and press a bar (200-650 g) for 15-60 s. A stainless-steel cannula was inserted into the right lateral ventricle for I.C.V. injection of drugs, and a common carotid artery was catheterized to measure mean arterial pressure (MAP) and HR. The number of exercise trials and changes in MAP, HR and force were pooled for 30 min periods. After the cats exercised for 30 min, either artificial cerebrospinal fluid (CSF) or clonidine (2 or 5 micrograms) were administered intracerebroventricularly. 2. Before clonidine injection, fifty-two exercise trials increased MAP and HR by 15 +/- 3 mmHg and 41 +/- 5 beats min-1, respectively. Administration of clonidine (2 micrograms) did not alter the resting MAP and HR, but attenuated the increases in MAP and HR in response to exercise (0-30 min post-clonidine: n = 81; delta MAP, 6 +/- 3 mmHg; delta HR, 20 +/- 6 beats min-1; 30-60 min post-clonidine: n = 71; delta MAP, 4 +/- 4 mmHg; delta HR, 17 +/- 8 beats min-1). Administration of artificial CSF I.C.V. had no effect on the cardiovascular responses to static exercise. 3. An increased dose of clonidine (5 micrograms) decreased resting MAP and HR by 31 +/- 7 mmHg and 37 +/- 7 beats min-1, respectively, and markedly blunted the cardiovascular responses to exercise (pre-clonidine: n = 52; delta MAP, 17 +/- 3 mmHg; delta HR, 38 +/- 5 beats min-1; post-clonidine 0-30 min: n = 66; delta MAP, 4 +/- 2 mmHg; delta HR, 15 +/- 5 beats min-1; post-clonidine 30-60 min: n = 60; delta MAP, 4 +/- 2 mmHg; delta HR, 14 +/- 6 beats min-1). Pretreatment with the alpha 2-adrenergic antagonist, yohimbine (8 micrograms, I.C.V.), blocked the

  8. Neuropeptides in the posterodorsal medial amygdala modulate central cardiovascular reflex responses in awake male rats

    PubMed Central

    Quagliotto, E.; Casali, K.R.; Dal Lago, P.; Rasia-Filho, A.A.

    2014-01-01

    The rat posterodorsal medial amygdala (MePD) links emotionally charged sensory stimuli to social behavior, and is part of the supramedullary control of the cardiovascular system. We studied the effects of microinjections of neuroactive peptides markedly found in the MePD, namely oxytocin (OT, 10 ng and 25 pg; n=6/group), somatostatin (SST, 1 and 0.05 μM; n=8 and 5, respectively), and angiotensin II (Ang II, 50 pmol and 50 fmol; n=7/group), on basal cardiovascular activity and on baroreflex- and chemoreflex-mediated responses in awake adult male rats. Power spectral and symbolic analyses were applied to pulse interval and systolic arterial pressure series to identify centrally mediated sympathetic/parasympathetic components in the heart rate variability (HRV) and arterial pressure variability (APV). No microinjected substance affected basal parameters. On the other hand, compared with the control data (saline, 0.3 µL; n=7), OT (10 ng) decreased mean AP (MAP50) after baroreflex stimulation and increased both the mean AP response after chemoreflex activation and the high-frequency component of the HRV. OT (25 pg) increased overall HRV but did not affect any parameter of the symbolic analysis. SST (1 μM) decreased MAP50, and SST (0.05 μM) enhanced the sympathovagal cardiac index. Both doses of SST increased HRV and its low-frequency component. Ang II (50 pmol) increased HRV and reduced the two unlike variations pattern of the symbolic analysis (P<0.05 in all cases). These results demonstrate neuropeptidergic actions in the MePD for both the increase in the range of the cardiovascular reflex responses and the involvement of the central sympathetic and parasympathetic systems on HRV and APV. PMID:25424367

  9. Leptin in nucleus of the solitary tract alters the cardiovascular responses to aortic baroreceptor activation.

    PubMed

    Ciriello, John

    2013-06-01

    Recent data suggests that neurons expressing the long form of the leptin receptor form at least two distinct groups within the caudal nucleus of the solitary tract (NTS): a group within the lateral NTS (Slt) and one within the medial (Sm) and gelantinosa (Sg) NTS. Discrete injections of leptin into Sm and Sg, a region that receives chemoreceptor input, elicit increases in arterial pressure (AP) and renal sympathetic nerve activity (RSNA). However, the effect of microinjections of leptin into Slt, a region that receives baroreceptor input is unknown. Experiments were done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar or Zucker obese rat to determine leptin's effect in Slt on heart rate (HR), AP and RSNA during electrical stimulation of the aortic depressor nerve (ADN). Depressor sites within Slt were first identified by the microinjection of l-glutamate (Glu; 0.25M; 10nl) followed by leptin microinjections. In the Wistar rat leptin microinjection (50ng; 20nl) into depressor sites within the lateral Slt elicited increases in HR and RSNA, but no changes in AP. Additionally, leptin injections into Slt prior to Glu injections at the same site or to stimulation of the ADN were found to attenuate the decreases in HR, AP and RSNA to both the Glu injection and ADN stimulation. In Zucker obese rats, leptin injections into NTS depressor sites did not elicit cardiovascular responses, nor altered the cardiovascular responses elicited by stimulation of ADN. Those data suggest that leptin acts at the level of NTS to alter the activity of neurons that mediate the cardiovascular responses to activation of the aortic baroreceptor reflex. PMID:23535030

  10. Concord Grape Juice Polyphenols and Cardiovascular Risk Factors: Dose-Response Relationships

    PubMed Central

    Blumberg, Jeffrey B.; Vita, Joseph A.; Chen, C. -Y. Oliver

    2015-01-01

    Pure fruit juices provide nutritional value with evidence suggesting some of their benefits on biomarkers of cardiovascular disease risk may be derived from their constituent polyphenols, particularly flavonoids. However, few data from clinical trials are available on the dose-response relationship of fruit juice flavonoids to these outcomes. Utilizing the results of clinical trials testing single doses, we have analyzed data from studies of 100% Concord grape juice by placing its flavonoid content in the context of results from randomized clinical trials of other polyphenol-rich foods and beverages describing the same outcomes but covering a broader range of intake. We selected established biomarkers determined by similar methods for measuring flow-mediated vasodilation (FMD), blood pressure, platelet aggregation, and the resistance of low density lipoprotein cholesterol (LDL) to oxidation. Despite differences among the clinical trials in the treatment, subjects, and duration, correlations were observed between the dose and FMD. Inverse dose-response relationships, albeit with lower correlation coefficients, were also noted for the other outcomes. These results suggest a clear relationship between consumption of even modest serving sizes of Concord grape juice, flavonoid intake, and effects on risk factors for cardiovascular disease. This approach to dose-response relationships may prove useful for testing other individual foods and beverages. PMID:26633488

  11. Effects of intracisternal administration of cannabidiol on the cardiovascular and behavioral responses to acute restraint stress.

    PubMed

    Granjeiro, Erica M; Gomes, Felipe V; Guimarães, Francisco S; Corrêa, Fernando M A; Resstel, Leonardo B M

    2011-10-01

    Systemic administration of cannabidiol (CBD), a non-psychotomimetic compound from Cannabis sativa, attenuates the cardiovascular and behavioral responses to restraint stress. Although the brain structures related to CBD effects are not entirely known, they could involve brainstem structures responsible for cardiovascular control. Therefore, to investigate this possibility the present study verified the effects of CBD (15, 30 and 60 nmol) injected into the cisterna magna on the autonomic and behavioral changes induced by acute restraint stress. During exposure to restraint stress (1h) there was a significant increase in mean arterial pressure (MAP) and heart rate (HR). Also, 24h later the animals showed a decreased percentage of entries onto the open arms of the elevated plus-maze. These effects were attenuated by CBD (30 nmol). The drug had no effect on MAP and HR baseline values. These results indicate that intracisternal administration of CBD can attenuate autonomic responses to stress. However, since CBD decreased the anxiogenic consequences of restraint stress, it is possible that the drug is also acting on forebrain structures. PMID:21771609

  12. Effect of hindlimb suspension on cardiovascular responses to sympathomimetics and lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Overton, J. Michael; Tipton, Charles M.

    1990-01-01

    To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: (1) cage control (n = 15, CON), (2) horizontal suspension (n = 15, HOZ), and (3) head-down suspension (n = 18, HDS). Testing included lower body negative pressure administered during chloralose-urethan anesthesia and graded doses of sympathomimetic agents (norepinephrine, phenylephrine, and tyramine) administered to conscious unrestrained animals. Both HDS and HOZ were associated with a small decrease in the hypotensive response to lower body negative pressure. The HOZ group, but not the HDS group, exhibited augmented reflex tachycardia. Furthermore, both HDS and HOZ groups manifested reduced pressor responses to phenylephrine after treatment. These reductions were associated with significantly attenuated increases in mesenteric vascular resistance. However, baroreflex control of heart rate was not altered by the treatment conditions. Collectively, these results indicate that 9 days of HDS in rats does not elicit hemodynamic response patterns generally associated with cardiovascular deconditioning induced by hypogravic conditions.

  13. Effects of whole-body cryotherapy duration on thermal and cardio-vascular response.

    PubMed

    Fonda, Borut; De Nardi, Massimo; Sarabon, Nejc

    2014-05-01

    Whole-body cryotherapy (WBC) is the exposure of minimally dressed participants to very cold air, either in a specially designed chamber (cryo-chamber) or cabin (cryo-cabin), for a short period of time. Practitioners are vague when it comes to recommendations on the duration of a single session. Recommended exposure for cryo-chamber is 150s, but no empirically based recommendations are available for a cryo-cabin. Therefore the aim of this study was to examine thermal and cardio-vascular responses after 90, 120, 150 and 180s of WBC in a cryo-cabin. Our hypothesis was that skin temperature would be significantly lower after longer exposers. Twelve male participants (age 23.9±4.2 years) completed four WBC of different durations (90, 120, 150 and 180s) in a cryo-cabin. Thermal response, heart rate and blood pressure were measured prior, immediately after, 5min after and 30min after the session. Skin temperature differed significantly among different durations, except between 150 and 180s. There was no significant difference in heart rate and blood pressure. Thermal discomfort during a single session displayed a linear increase throughout the whole session. Our results indicate that practitioners and clinicians using cryo-cabin for WBC do not need to perform sessions longer than 150s. We have shown that longer sessions do not substantially affect thermal and cardio-vascular response, but do increase thermal discomfort. PMID:24802149

  14. Individual differences in the impact of attentional bias training on cardiovascular responses to stress in women.

    PubMed

    Higgins, Niamh M; Hughes, Brian M

    2012-07-01

    Experimental studies show that training people to attend to negative stimuli makes them more likely to respond with greater anxiety to stress. The present study investigated this effect in students using measures of cardiovascular responses to stress and examined whether individual differences influence the impact of attention training on stress responses. Using a standard dot probe task, 30 participants underwent negative attentional bias training and 34 participants underwent anti-negative training before completing a stressful speech task. Results indicated that, overall, participants exhibited acclimatization to the procedures (indicated by a dip in blood pressure post-training) and normal stress responding (indicated by elevated blood pressure in response to stress; p<.001). However, consideration of participants' scores for neuroticism/emotional-stability revealed important differences in how the intervention impacted on cardiovascular profiles (p=.008). For participants with high neuroticism scores, the negative attentional bias intervention elicited more exaggerated stress responding than the anti-negative intervention. For those with low neuroticism scores (i.e., emotionally stable participants), the anti-negative intervention was associated with elevated post-intervention blood pressure and higher blood pressure reactivity to stress. These findings provide evidence of the impact of attentional bias manipulation on physiological stress reactivity and suggest the effect is highly contingent on individual temperaments. PMID:21970526

  15. Chemosensitivity, Cardiovascular Risk, and the Ventilatory Response to Exercise in COPD

    PubMed Central

    Stickland, Michael K.; Fuhr, Desi P.; Edgell, Heather; Byers, Brad W.; Bhutani, Mohit; Wong, Eric Y. L.; Steinback, Craig D.

    2016-01-01

    COPD is associated with elevated cardiovascular risk and a potentiated ventilatory response to exercise. Enhanced carotid chemoreceptor (CC) activity/sensitivity is present in other clinical conditions, has been shown to contribute to sympathetic vasoconstrictor outflow, and is predictive of mortality. CC activity/sensitivity, and the resulting functional significance, has not been well examined in COPD. We hypothesized that CC activity/sensitivity would be elevated in COPD, and related to increased pulse wave velocity (a marker of CV risk) and the ventilatory response to exercise. Methods: 30 COPD patients and 10 healthy age-matched controls were examined. Participants performed baseline cardiopulmonary exercise and pulmonary function testing. CC activity was later evaluated by the drop in ventilation with breathing 100% O2, and CC sensitivity was then assessed by the ventilatory response to hypoxia (ΔVE/ΔSpO2). Peripheral arterial stiffness was subsequently evaluated by measurement of pulse wave velocity (PWV) using applanation tonometry while the subjects were breathing room air, and then following chemoreceptor inhibition by breathing 100% O2 for 2 minutes. Results: CC activity, CC sensitivity, PWV and the ventilatory response to exercise were all increased in COPD relative to controls. CC sensitivity was related to PWV; however, neither CC activity nor CC sensitivity was related to the ventilatory response to exercise in COPD. CC inhibition by breathing 100% O2 normalized PWV in COPD, while no effect was observed in controls. Conclusion: CC activity and sensitivity are elevated in COPD, and appear related to cardiovascular risk; however, CC activity/sensitivity does not contribute to the potentiated ventilatory response to exercise. PMID:27355356

  16. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    NASA Technical Reports Server (NTRS)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  17. Human cardiovascular response to sympathomimetic agents during head-down bed rest: the effect of dietary sodium

    NASA Technical Reports Server (NTRS)

    Williams, W. J.; Stuart, C. A.; Fortney, S. M.; Pietrzyk, R. A.; Chen, Y. M.; Whitson, P. A.

    1994-01-01

    Changes in sympathoadrenal function and cardiovascular deconditioning have long been recognized as a feature of the physiological adaptation to microgravity. The deconditioning process, coupled with altered hydration status, is thought to significantly contribute to orthostatic intolerance upon return to Earth gravity. The cardiovascular response to stimulation by sympathomimetic agents before, during, and after exposure to simulated microgravity was determined in healthy volunteers equilibrated on normal or high sodium diets in order to further the understanding of the deconditioning process.

  18. Maternal antioxidant blocks programmed cardiovascular and behavioural stress responses in adult mice

    PubMed Central

    ROGHAIR, Robert D.; WEMMIE, John A.; VOLK, Kenneth A.; SCHOLZ, Thomas D.; LAMB, Fred S.; SEGAR, Jeffrey L.

    2013-01-01

    Intra-uterine growth restriction is an independent risk factor for adult psychiatric and cardiovascular diseases. In humans, intra-uterine growth restriction is associated with increased placental and fetal oxidative stress, as well as down-regulation of placental 11β-HSD (11β-hydroxysteroid dehydrogenase). Decreased placental 11β-HSD activity increases fetal exposure to maternal glucocorticoids, further increasing fetal oxidative stress. To explore the developmental origins of co-morbid hypertension and anxiety disorders, we increased fetal glucocorticoid exposure by administering the 11β-HSD inhibitor CBX (carbenoxolone; 12 mg · kg−1 of body weight · day−1) during the final week of murine gestation. We hypothesized that maternal antioxidant (tempol throughout pregnancy) would block glucocorticoid-programmed anxiety, vascular dysfunction and hypertension. Anxiety-related behaviour (conditioned fear) and the haemodynamic response to stress were measured in adult mice. Maternal CBX administration significantly increased conditioned fear responses of adult females. Among the offspring of CBX-injected dams, maternal tempol markedly attenuated the behavioural and cardiovascular responses to psychological stress. Compared with offspring of undisturbed dams, male offspring of dams that received daily third trimester saline injections had increased stress-evoked pressure responses that were blocked by maternal tempol. In contrast, tempol did not block CBX-induced aortic dysfunction in female mice (measured by myography and lucigenin-enhanced chemiluminescence). We conclude that maternal stress and exaggerated fetal glucocorticoid exposure enhance sex-specific stress responses, as well as alterations in aortic reactivity. Because concurrent tempol attenuated conditioned fear and stress reactivity even among the offspring of saline-injected dams, we speculate that antenatal stressors programme offspring stress reactivity in a cycle that may be broken by antenatal

  19. Acute cardiovascular responses while playing virtual games simulated by Nintendo Wii®

    PubMed Central

    Rodrigues, Gusthavo Augusto Alves; Felipe, Danilo De Souza; Silva, Elisangela; De Freitas, Wagner Zeferino; Higino, Wonder Passoni; Da Silva, Fabiano Fernandes; De Carvalho, Wellington Roberto Gomes; Aparecido de Souza, Renato

    2015-01-01

    [Purpose] This investigation evaluated the acute cardiovascular responses that occur while playing virtual games (aerobic and balance) emulated by Nintendo Wii®. [Subjects] Nineteen healthy male volunteers were recruited. [Methods] The ergospirometric variables of maximum oxygen consumption, metabolic equivalents, and heart rate were obtained during the aerobic (Obstacle Course, Hula Hoop, and Free Run) and balance (Soccer Heading, Penguin Slide, and Table Tilt) games of Wii Fit Plus® software. To access and analyze the ergospirometric information, a VO2000 analyzer was used. Normalized data (using maximum oxygen consumption and heart rate) were analyzed using repeated measures analysis of variance and Scheffe’s test. [Results] Significant differences were found among the balance and aerobic games in all variables analyzed. In addition, the Wii exercises performed were considered to be of light (balance games) and moderate (aerobic games) intensity in accordance with American College Sports Medicine exercise stratification. [Conclusion] Physical activity in a virtual environment emulated by Nintendo Wii® can change acute cardiovascular responses, primarily when Wii aerobic games are performed. These results support the use of the Nintendo Wii® in physical activity programs. PMID:26504308

  20. Role of Autonomic Reflex Arcs in Cardiovascular Responses to Air Pollution Exposure

    PubMed Central

    Hazari, Mehdi S.; Farraj, Aimen K.

    2016-01-01

    The body responds to environmental stressors by triggering autonomic reflexes in the pulmonary receptors, baroreceptors, and chemoreceptors to maintain homeostasis. Numerous studies have shown that exposure to various gases and airborne particles can alter the functional outcome of these reflexes, particularly with respect to the cardiovascular system. Modulation of autonomic neural input to the heart and vasculature following direct activation of sensory nerves in the respiratory system, elicitation of oxidative stress and inflammation, or through other mechanisms is one of the primary ways that exposure to air pollution affects normal cardiovascular function. Any homeostatic process that utilizes the autonomic nervous system to regulate organ function might be affected. Thus, air pollution and other inhaled environmental irritants have the potential to alter both local airway function and baro-and chemoreflex responses, which modulate autonomic control of blood pressure and detect concentrations of key gases in the body. While each of these reflex pathways causes distinct responses, the systems are heavily integrated and communicate through overlapping regions of the brainstem to cause global effects. This short review summarizes the function of major pulmonary sensory receptors, baroreceptors, and carotid body chemoreceptors and discusses the impacts of air pollution exposure on these systems. PMID:25123706

  1. Cardiovascular responses to exercise as functions of absolute and relative work load

    NASA Technical Reports Server (NTRS)

    Lewis, S. F.; Taylor, W. F.; Graham, R. M.; Pettinger, W. A.; Schutte, J. E.; Blomqvist, C. G.

    1983-01-01

    The roles of absolute and relative oxygen uptake (VO2 and percent of muscle group specific VO2-max) as determinants of the cardiovascular and ventilatory responses to exercise over a wide range of active muscle mass are investigated. Experiments were conducted using four types of dynamic exercise: one-arm curl, one-arm cranking, and one and two-leg cycling at four different relative work loads (25, 50, 75, and 100 percent of VO2-max) for the corresponding muscle group. Results show that VO2 during maximal one-arm curl, one-arm cranking, and one-leg cycling averaged 20, 50, and 75 percent, respectively, of that for maximal two-leg cycling. Cardiac output was determined to be linearly related to VO2 with a similar slope and intercept for each type of exercise, and the heart rate at a given percent VO2-max was higher with larger active muscle mass. It is concluded that the cardiovascular responses to exercise was determined to a large extent by the active muscle mass and the absolute oxygen uptake, with the principal feature appearing to be the tight linkage between systematic oxygen transport and utilization.

  2. Acute cardiovascular responses while playing virtual games simulated by Nintendo Wii(®).

    PubMed

    Rodrigues, Gusthavo Augusto Alves; Felipe, Danilo De Souza; Silva, Elisangela; De Freitas, Wagner Zeferino; Higino, Wonder Passoni; Da Silva, Fabiano Fernandes; De Carvalho, Wellington Roberto Gomes; Aparecido de Souza, Renato

    2015-09-01

    [Purpose] This investigation evaluated the acute cardiovascular responses that occur while playing virtual games (aerobic and balance) emulated by Nintendo Wii(®). [Subjects] Nineteen healthy male volunteers were recruited. [Methods] The ergospirometric variables of maximum oxygen consumption, metabolic equivalents, and heart rate were obtained during the aerobic (Obstacle Course, Hula Hoop, and Free Run) and balance (Soccer Heading, Penguin Slide, and Table Tilt) games of Wii Fit Plus(®) software. To access and analyze the ergospirometric information, a VO2000 analyzer was used. Normalized data (using maximum oxygen consumption and heart rate) were analyzed using repeated measures analysis of variance and Scheffe's test. [Results] Significant differences were found among the balance and aerobic games in all variables analyzed. In addition, the Wii exercises performed were considered to be of light (balance games) and moderate (aerobic games) intensity in accordance with American College Sports Medicine exercise stratification. [Conclusion] Physical activity in a virtual environment emulated by Nintendo Wii(®) can change acute cardiovascular responses, primarily when Wii aerobic games are performed. These results support the use of the Nintendo Wii(®) in physical activity programs. PMID:26504308

  3. Science, Ethics and the Climate Responsibilities of Industrial Carbon Producers

    NASA Astrophysics Data System (ADS)

    Frumhoff, P. C.

    2014-12-01

    The question of responsibility for climate change lies at the heart of societal debate over actions to curb greenhouse gas emissions and prepare for now unavoidable climate impacts. The UN Framework Convention on Climate Change established the principle of "common but differentiated responsibilities" among nations, signaling the recognition that industrialized nations who had produced the lion's share of historic emissions bore particular responsibility for avoiding dangerous interference with the climate system. But climate responsibilities can be distributed in other ways as well. This talk focuses on the scientific, historical and ethical basis for considering the climate responsibilities of the major fossil energy companies that have produced and marketed the coal, oil and natural gas whose use largely drives global warming, often while investing in efforts to discredit the scientific evidence and prevent policies that would encourage a transition to low-carbon energy. Earth scientists and scientific societies who rely on financial support from these companies have an opportunity to consider what ethical stance they might take to align their research, scientific understanding and values.

  4. Difficulty, effort and cardiovascular response to a working memory challenge: Older adults with and without mild cognitive impairment.

    PubMed

    Stewart, Christopher C; Wright, Rex A; Griffith, H Randall

    2016-06-01

    We presented cognitively healthy older adults and patients with mild cognitive impairment (MCI) three versions of a modified Sternberg memory task designed to range in difficulty from low to high. Among cognitively healthy older adults, blood pressure responses assessed during the work periods rose with difficulty. By contrast, among MCI patients, blood pressure responses assessed during the work periods were low irrespective of difficulty. Findings are discussed primarily in relation to a conceptual analysis concerned with ability determinants of effort (task engagement) and associated cardiovascular responses. They also are discussed in the context of other recent cardiovascular studies involving older adults and with regard to the potential for exaggerated cardiovascular responses to accelerate cognitive decline in advanced age. PMID:27109608

  5. Fluid/electrolyte balance and cardiovascular responses - Head-down tilted rats

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Deavers, D. R.; Meininger, G. A.

    1990-01-01

    Results are presented on cardiovascular and fluid/electrolyte balance responses of rats to a 7-day-long whole-body suspension (WBS) with about 20-deg head-down tilt (HDT), followed by 7 days of recovery. Compared with horizontally positioned (N-HDT) rats serving as controls, the Na intake of HDT rats was significantly reduced during the first 3 days of HDT, and urinary and fecal Na loss exceeded the Na intake during days 5 and 6. Changes during the days of recovery showed adjustments and reestablishment of Na balance. Urinary K losses increased progressively during the 7 days of HDT, but, with the exception of days 1-3 of HDT, when the K intake was significantly reduced, the K balance was retained. Changes in cardiac responses (including elevations in mean, diastolic, and systolic arterial pressures) paralleled changes in fluid and electrolyte balance during the HDT period.

  6. Cardiovascular responses to arm static exercise in men with thoracic spinal cord lesions.

    PubMed

    Sakamoto, Keiko; Nakamura, Takeshi; Umemoto, Yasunori; Koike, Yumi; Sasaki, Yusuke; Tajima, Fumihiro

    2012-02-01

    Isometric muscle contraction (static exercise) induces circulatory response. Static exercise in individuals with thoracic spinal cord injury (TSCI) induces cardiovascular response and blood redistribution to the non-exercising muscles. The aim of our study was to determine the circulatory response during arm static exercise in individuals with TSCI and able-bodied (AB) controls. Mean blood pressure (MBP), heart rate (HR), cardiac output (CO), leg skin blood flow (SBF), and leg muscle blood flow (MBF) were recorded noninvasively, total peripheral resistance (TPR) was estimated by dividing MBP by CO, and hormonal changes were measured before, during and after static 35% maximal voluntary contraction (MVC) of the arm flexor muscles in seven male individuals with TSCI (T7-T11) and seven age-comparable AB control (32.2 ± 7.6 and 31.0 ± 4.7 years, respectively). The 35% MVC was similar in TSCI and AB individuals (107.3 ± 28.2 and 101.0 ± 22.5 N, respectively). HR, CO, MBP, TPR, SBF and MBF increased in both groups during arm static exercise. Plasma epinephrine concentration increased during arm static exercise in AB controls only (P < 0.05). Circulation to leg muscles was similar in TSCI and AB individuals and the lack of sympathetic vasoconstriction in the paralyzed leg area did not alter the cardiovascular responses during 35% MVC of arm static exercise. We conclude that sympathetic vasoconstriction in the resting leg area did not contribute to the pressor reflex during 35% MVC of arm static exercise. PMID:21656231

  7. Assessment of cardiovascular response to treadmill exercise in normal healthy Indian adolescents.

    PubMed

    Pande, Sushma S; Pande, Santosh R; Dhore, Rajendra B; Daphale, Ajay V; Parate, Vrushali R; Patel, Shishir S; Agrekar, Sushil H

    2012-01-01

    The study aims to assess the cardiovascular response to treadmill exercise test in healthy Indian adolescents. A group of 50 healthy adolescents took part in the study. Cardiovascular response was assessed by using treadmill exercise test as per Bruce protocol. Pulse rate, blood pressure and ECG were recorded before, during and after undertaking the treadmill test. Mean age and body mass index (BMI) were 18.7 +/- 0.51 yrs. and 21.4 +/- 3.44 kg/m2 respectively. Karl Pearson Correlation analysis showed highly significant negative correlation between BMI and exercise time (r = -0.598, P<0.001) and between resting DBP and Exercise Time (r = -0.424, P<0.002). While BMI and DBP showed highly significant positive correlation (r = 0.463, P<0.001). During exercise pulse and SBP rose and DBP fell. SBP rose from mean 122 to 175 (rise by 53 mm of Hg) and DBP fell from mean 78 to 65 (fall by 13 mm of Hg). One min recovery pulse was 156 indicating 22% fall from target heart rate. All the parameters returned to near resting value at 6 min recovery. In 30% students DBP showed exaggerated response i.e. rise during exercise. These students had more BMI and higher resting DBP as compared to other students, which could be the reason for exaggerated response in these participants. In ECG there were no significant ST/T changes during exercise or recovery period. This study provides normal data for small sample of healthy Indian adolescents when subjected to treadmill exercise test. PMID:23029962

  8. Opioid receptors in the prelimbic cortex modulate restraint stress-induced cardiovascular responses in the rat.

    PubMed

    Fassini, Aline; Scopinho, América A; Resstel, Leonardo B M; Correa, Fernando M A

    2014-10-01

    The prelimbic cortex (PL) is involved in the control of behavioral and autonomic responses to stress. The present study aimed to investigate whether opioid neurotransmission in the PL modulates autonomic responses evoked by restraint stress (RS). Bilateral microinjection of 0.03, 0.3 and 3 nmol/100 nL of the nonselective opioid antagonist naloxone into the PL reduced pressure and tachycardiac responses evoked by RS. However, no effects were observed after its injection at doses of 0.003 and 30 nmol/100 nL, thus resulting in an inverted U-shaped dose-inhibition curve. Similar to naloxone, the selective μ-opioid antagonist CTAP, and the selective κ-opioid antagonist nor-BNI, also reduced MAP and HR increases induced by RS when injected into the PL, whereas treatment with the selective δ-opioid antagonist naltrindole did not affect the pressor and tachycardiac response caused by RS. Blockade of opioid neurotransmission in the PL did not affect the fall in tail temperature and increase in body temperature induced by RS. The present results confirm the involvement of PL opioid neurotransmission in the modulation of cardiovascular responses evoked during the exposure to an aversive situation, and suggest that responses observed after the blockade of local opioid receptors is due to alterations in PL neuronal activity. Furthermore, these results suggest that a distinct circuitry is involved in modulation of the sympathetic output to different vascular territories. PMID:24813527

  9. Island tameness: an altered cardiovascular stress response in Galápagos marine iguanas.

    PubMed

    Vitousek, Maren N; Romero, L Michael; Tarlow, Elisa; Cyr, Nicole E; Wikelski, Martin

    2010-03-30

    Island tameness is a widely documented phenomenon in which island species, particularly those that have evolved with no or few natural predators, show a greatly reduced behavioral response when faced with unfamiliar predators. This insufficient anti-predator response has led to widespread population declines among many island species exposed to novel predators, and has become a serious conservation problem. Despite its prevalence, the underlying physiology of island tameness is not known. Here we report that although Galápagos marine iguanas (Amblyrhynchus cristatus) initiated flight from an evolutionarily recent and unfamiliar potential predator (humans), they failed to show the cardiovascular stress response that facilitates successful escape, even after a prior capture experience. In contrast, when approached by a native predator (the Galápagos hawk; Buteo galapagoensis), marine iguanas show markedly increased heart rate independent of initiating escape movement. The secretion of catecholamines appears to be central to the initiation of escape behavior: naïve animals remotely injected with epinephrine immediately increased flight initiation distance, whereas those injected with corticosterone did not. Our results provide the first evidence that muted escape behavior in predator-naïve species is indicative of both a cognitive deficit in recognizing potential predators and a catecholamine deficit in response. Understanding how the response to predators differs in predator-naïve species could enable the design of maximally effective techniques for inducing an anti-predator response in these vulnerable species. PMID:20109476

  10. Malnutrition alters the cardiovascular responses induced by central injection of tityustoxin in Fischer rats.

    PubMed

    Silva, Fernanda Cacilda Santos; Guidine, Patrícia Alves; Ribeiro, Mara Fernandes; Fernandes, Luciano Gonçalves; Xavier, Carlos Henrique; de Menezes, Rodrigo Cunha; Silva, Marcelo Eustáquio; Moraes-Santos, Tasso; Moraes, Márcio Flávio; Chianca, Deoclécio Alves

    2013-12-15

    Scorpion envenoming and malnutrition are considered two important public health problems in Brazil, involving mainly children. Both these conditions are more common among the economically stratified lower income portion of the population, thus suggesting that these factors should be analyzed concomitantly. It is known that cardiorespiratory manifestations, as cardiac arrhythmias, arterial hypertension and hypotension, pulmonary edema and circulatory failure are the main "causa mortis" of scorpion envenomation. Additionally, there are evidences in the literature that deficiencies in dietary intake endanger the CNS and modify the cardiovascular homeostasis. Then, the objective of this work is to evaluate the protein malnourished effect on cardiovascular responses induced by tityustoxin (TsTX, an α-type toxin extracted from the Tityus serrulatus scorpion venom). Fischer rats (n = 20) were injected i.c.v. with TsTX and divided in control and malnorished groups, which were, respectively, submitted to a control and a low-protein diet. Arterial pressure recordings were done until death of the animals. Although both groups presented an increased mean arterial pressure after TsTX injection, this increase was smaller and delayed in malnourished rats, when compared to control rats. In addition, heart rate increased only in rats from the control group. Finally, malnourished rats had an increase in survival time (9:9/13.5 vs. 15.5:10.5/18 min; p = 0.0009). In summary, our results suggest that the protein restriction attenuates the cardiovascular manifestations resulting from TsTX action on CNS. PMID:24060375

  11. Structure response and damage produced by airblast from surface mining

    SciTech Connect

    Siskind, D.E.; Stachura, V.J.; Stagg, M.S.; Kopp, J.W.

    1980-01-01

    The Bureau of Mines studied airblast from surface mining to assess its damage and annoyance potential, and to determine safe levels and appropriate measurement techniques. Research results obtained from direct measurements of airblast-produced structure responses, damage, and analysis of instrument characteristics were combined with studies of sonic booms and human response to transient overpressures. Safe levels of airblast were found to be 134 db (0.1 Hz), 133 db (2 Hz), 129 db (6 Hz), and 105 db C-slow. These four airblast levels and measurement methods are equivalent in terms of structure response, and any one could be used as a safe-level criterion. Of the four methods, only the 0.1-Hz high-pass linear method accurately measures the total airblast energy present; however, the other three were found to adequately quantify the structure response and also represent techniques that are readily available to industry. Where a single airblast measuring system must be used, the 2-Hz linear peak response is the best overall compromise. The human response and annoyance problem from airblast is probably caused primarily by wall rattling and the resulting secondary noises. Although these will not entirely be precluded by the recommended levels, they are low enough to preclude damage to residential structures and any possible human injury over the long term.

  12. Integration of autonomic and local mechanisms in regulating cardiovascular responses to heating and cooling in a reptile (Crocodylus porosus).

    PubMed

    Seebacher, Frank; Franklin, Craig E

    2004-10-01

    Reptiles change heart rate and blood flow patterns in response to heating and cooling, thereby decreasing the behavioural cost of thermoregulation. We tested the hypothesis that locally produced vasoactive substances, nitric oxide and prostaglandins, mediate the cardiovascular response of reptiles to heat. Heart rate and blood pressure were measured in eight crocodiles (Crocodylus porosus) during heating and cooling and while sequentially inhibiting nitric-oxide synthase and cyclooxygenase enzymes. Heart rate and blood pressure were significantly higher during heating than during cooling in all treatments. Power spectral density of heart rate and blood pressure increased significantly during heating and cooling compared to the preceding period of thermal equilibrium. Spectral density of heart rate in the high frequency band (0.19-0.70 Hz) was significantly greater during cooling in the saline treatment compared to when nitric-oxide synthase and cyclooxygenase enzymes were inhibited. Cross spectral analysis showed that changes in blood pressure preceded heart rate changes at low frequencies (< 0.1 Hz) only. We conclude that the autonomic nervous system controls heart rate independently from blood pressure at higher frequencies while blood pressure changes determine heart rate at lower frequencies. Nitric oxide and prostaglandins do not control the characteristic heart rate hysteresis response to heat in C. porosus, although nitric oxide was important in buffering blood pressure against changes in heart rate during cooling, and inhibition caused a compensatory decrease in parasympathetic stimulation of the heart. PMID:15340754

  13. Late-developing rostral ventrolateral medullary surface responses to cardiovascular challenges during sleep.

    PubMed

    Richard, Christopher A; Rector, David M; Macey, Paul M; Ali, Noorjahan; Harper, Ronald M

    2003-09-19

    Pressor and depressor manipulations are usually followed by compensatory autonomic, respiratory, somatomotor or arousal responses that limit the extent of blood pressure change. Of neural sites participating in blood pressure control, the rostral ventrolateral medullary surface (RVLMS) contributes significantly, and exhibits rapid-onset overall activity declines and increases to pressor and depressor challenges, respectively. In addition, longer-latency physiological responses develop that further compensate for the homeostatic challenge; some of these later influences are associated with arousal. Late-developing RVLMS activity changes accompanying physiologic responses that normalize a cardiovascular manipulation may provide insights into compensatory neural mechanisms during sleep following sustained or extreme blood pressure changes. We used intrinsic optical imaging procedures in seven unanesthetized adult cats to examine RVLMS and control site responses to pressor and depressor challenges during sleep that resulted in somatomotor, respiratory, heart rate or electroencephalographic indications of late-developing (post-baroreflex) compensatory responses. Although initial RVLMS responses differed in direction between pressor and depressor challenges, neural activity increased later in both manipulations, coincident with overt physiological manifestations indicative of compensatory responses, including arousal. Arousal occurred in 44% of blood pressure challenges. Comparable late-developing neural activity increases were not apparent in control sites. Latencies of late RVLMS responses during rapid eye movement sleep were significantly longer than in quiet sleep for pressor challenges. The pattern of the late RVLMS responses was not dependent on arousal, and suggests that the RVLMS participates in both the early baroreflex response and the late-developing compensatory actions. PMID:12957369

  14. Acrolein inhalation alters arterial blood gases and triggers carotid body-mediated cardiovascular responses in hypertensive rats

    PubMed Central

    Perez, Christina M.; Hazari, Mehdi S.; Ledbetter, Allen D.; Haykal-Coates, Najwa; Carll, Alex P.; Cascio, Wayne E.; Winsett, Darrell W.; Costa, Daniel L.; Farraj, Aimen K.

    2016-01-01

    Context Air pollution exposure affects autonomic function, heart rate, blood pressure and left ventricular function. While the mechanism for these effects is uncertain, several studies have reported that air pollution exposure modifies activity of the carotid body, the major organ that senses changes in arterial oxygen and carbon dioxide levels, and elicits downstream changes in autonomic control and cardiac function. Objective We hypothesized that exposure to acrolein, an unsaturated aldehyde and mucosal irritant found in cigarette smoke and diesel exhaust, would activate the carotid body chemoreceptor response and lead to secondary cardiovascular responses in rats. Materials and methods Spontaneously hypertensive (SH) rats were exposed once for 3 h to 3 ppm acrolein gas or filtered air in whole body plethysmograph chambers. To determine if the carotid body mediated acrolein-induced cardiovascular responses, rats were pretreated with an inhibitor of cystathionine γ-lyase (CSE), an enzyme essential for carotid body signal transduction. Results Acrolein exposure induced several cardiovascular effects. Systolic, diastolic and mean arterial blood pressure increased during exposure, while cardiac contractility decreased 1 day after exposure. The cardiovascular effects were associated with decreases in pO2, breathing frequency and expiratory time, and increases in sympathetic tone during exposure followed by parasympathetic dominance after exposure. The CSE inhibitor prevented the cardiovascular effects of acrolein exposure. Discussion and conclusion Pretreatment with the CSE inhibitor prevented the cardiovascular effects of acrolein, suggesting that the cardiovascular responses with acrolein may be mediated by carotid body-triggered changes in autonomic tone. (This abstract does not reflect EPA policy.) PMID:25600140

  15. Cardiovascular and endocrine responses to acute hypoxaemia during and following dexamethasone infusion in the ovine fetus

    PubMed Central

    Fletcher, Andrew J W; Gardner, David S; Edwards, C Mark B; Fowden, Abigail L; Giussani, Dino A

    2003-01-01

    This study investigated the effects of fetal treatment with dexamethasone on ovine fetal cardiovascular defence responses to acute hypoxaemia, occurring either during or 48 h following the period of glucocorticoid exposure. To address the mechanisms underlying these responses, chemoreflex function and plasma concentrations of catecholamines, neuropeptide Y (NPY) and vasopressin were measured. Under general halothane anaesthesia, 26 Welsh Mountain sheep fetuses were surgically prepared for long-term recording at between 117 and 120 days of gestation (dGA; term is ∼145 days) with vascular catheters and a Transonic flow probe around a femoral artery. Following at least 5 days of recovery, fetuses were randomly assigned to one of two experimental groups. After 48 h of baseline recording, at 125 ± 1 dGA, half of the fetuses (n = 13) were continuously infused i.v. with dexamethasone for 48 h at a rate of 2.06 ± 0.13 μg kg−1 h−1. The remaining 13 fetuses were infused with heparinized saline at the same rate (controls). At 127 ± 1 dGA, 2 days from the onset of infusions, seven fetuses from each group were subjected to 1 h of acute hypoxaemia. At 129 ± 1 dGA, 2 days after the end of infusions, six fetuses from each group were subjected to 1 h of acute hypoxaemia. Similar reductions in fetal partial pressure of arterial oxygen occurred in control and dexamethasone-treated fetuses during the acute hypoxaemia protocols. In control fetuses, acute hypoxaemia led to transient bradycardia, femoral vasoconstriction and significant increases in plasma concentrations of catecholamines, vasopressin and NPY. In fetuses subjected to acute hypoxaemia during dexamethasone treatment, the increase in plasma NPY was enhanced, the bradycardic response was prolonged, and the plasma catecholamine and vasopressin responses were diminished. In fetuses subjected to acute hypoxaemia 48 h following dexamethasone treatment, femoral vasoconstriction and plasma catecholamine and vasopressin

  16. Perceived Social Support, Coping Styles, and Chinese Immigrants’ Cardiovascular Responses to Stress

    PubMed Central

    Lee, Christine; Suchday, Sonia; Wylie-Rosett, Judith

    2011-01-01

    Background Social support and coping strategies are important determinants of health, especially for those in the immigrant community adjusting to a new environment. Purpose This study assessed the buffering effects of perceived social support and different coping styles on cardiovascular reactivity to stress among Chinese immigrants in the New York City Chinatown area. Method Participants (N = 50, 76% women, and 22–84 years old) completed questionnaires assessing their perceived social support and coping strategy preferences. They were then asked to recall a stress provoking event related to their immigration experience in a semi-structured interview format. Results Hierarchical multiple regression analyses confirmed the interaction effect between perceived social support and problem-focused, emotion-focused, or reappraisal coping on heart rate reactivity. Additionally, Chinese immigrants who upheld more Chinese values were highly correlated with stronger perceived availability of social support and were more likely to incorporate the use of problem-focused and reappraisal coping styles. Conclusion Findings suggest that high level of social support and the use of reappraisal coping strategies were associated with attenuated cardiovascular responses to stress. PMID:21472482

  17. Captive European starlings (Sturnus vulgaris) in breeding condition show an increased cardiovascular stress response to intruders.

    PubMed

    Dickens, Molly J; Nephew, Benjamin C; Romero, L Michael

    2006-01-01

    European starlings (Sturnus vulgaris) alter their physiology and behavior between seasons, becoming territorial during the spring/summer and flocking during the fall/winter. We used captive male starlings in breeding (photostimulated to 18L : 6D) and nonbreeding (11L : 13D) conditions to determine whether changing physiology and behavior alters their reaction to crowding. One or five intruders entered a resident's cage without human disturbance. A subcutaneous heart rate transmitter recorded cardiovascular output in residents. Corticosterone and testosterone were measured in plasma samples taken before and after the intrusion. While corticosterone concentrations did not change, heart rate changed significantly, indicating that these responses can be regulated independently. Long-day birds showed a significantly elevated heart rate response to the single-bird intrusion compared to short-day birds. Whereas five intruders elicited an identical peak response in both groups, long-day birds also demonstrated an equivalent response to one intruder. In addition, one intruder induced longer elevation in heart rate for long-day birds. Male starlings in breeding condition, therefore, demonstrate an increased sensitivity to additional conspecifics. This seasonal shift in response suggests that a higher tolerance for intrusion (i.e., considering a nearby starling as less stressful) may facilitate flocking behavior, while a lower tolerance may aid in territoriality. PMID:16927240

  18. Analysis of cardiovascular responses to the H2S donors Na2S and NaHS in the rat

    PubMed Central

    Yoo, Daniel; Jupiter, Ryan C.; Pankey, Edward A.; Reddy, Vishwaradh G.; Edward, Justin A.; Swan, Kevin W.; Peak, Taylor C.; Mostany, Ricardo

    2015-01-01

    Hydrogen sulfide (H2S) is an endogenous gaseous molecule formed from L-cysteine in vascular tissue. In the present study, cardiovascular responses to the H2S donors Na2S and NaHS were investigated in the anesthetized rat. The intravenous injections of Na2S and NaHS 0.03–0.5 mg/kg produced dose-related decreases in systemic arterial pressure and heart rate, and at higher doses decreases in cardiac output, pulmonary arterial pressure, and systemic vascular resistance. H2S infusion studies show that decreases in systemic arterial pressure, heart rate, cardiac output, and systemic vascular resistance are well-maintained, and responses to Na2S are reversible. Decreases in heart rate were not blocked by atropine, suggesting that the bradycardia was independent of parasympathetic activation and was mediated by an effect on the sinus node. The decreases in systemic arterial pressure were not attenuated by hexamethonium, glybenclamide, Nw-nitro-l-arginine methyl ester hydrochloride, sodium meclofenamate, ODQ, miconazole, 5-hydroxydecanoate, or tetraethylammonium, suggesting that ATP-sensitive potassium channels, nitric oxide, arachidonic acid metabolites, cyclic GMP, p450 epoxygenase metabolites, or large conductance calcium-activated potassium channels are not involved in mediating hypotensive responses to the H2S donors in the rat and that responses are not centrally mediated. The present data indicate that decreases in systemic arterial pressure in response to the H2S donors can be mediated by decreases in vascular resistance and cardiac output and that the donors have an effect on the sinus node independent of the parasympathetic system. The present data indicate that the mechanism of the peripherally mediated hypotensive response to the H2S donors is uncertain in the intact rat. PMID:26071540

  19. Pulmonary and cardiovascular responses of rats to inhalation of a commercial antimicrobial spray containing titanium dioxide nanoparticles

    PubMed Central

    McKinney, W.; Jackson, M.; Sager, T.M.; Reynolds, J.S.; Chen, B.T.; Afshari, A.; Krajnak, K.; Waugh, S.; Johnson, C.; Mercer, R.R.; Frazer, D.G.; Thomas, T.A.; Castranova, V.

    2015-01-01

    Our laboratory has previously demonstrated that application of an antimicrobial spray product containing titanium dioxide (TiO2) generates an aerosol of titanium dioxide in the breathing zone of the applicator. The present report describes the design of an automated spray system and the characterization of the aerosol delivered to a whole body inhalation chamber. This system produced stable airborne levels of TiO2 particles with a median count size diameter of 110 nm. Rats were exposed to 314 mg/m3 min (low dose), 826 mg/m3 min (medium dose), and 3638 mg/m3 min (high dose) of TiO2 under the following conditions: 2.62 mg/m3 for 2 h, 1.72 mg/m3 4 h/day for 2 days, and 3.79 mg/m3 4 h/day for 4 days, respectively. Pulmonary (breathing rate, specific airway resistance, inflammation, and lung damage) and cardiovascular (the responsiveness of the tail artery to constrictor or dilatory agents) endpoints were monitored 24 h post-exposure. No significant pulmonary or cardiovascular changes were noted at low and middle dose levels. However, the high dose caused significant increases in breathing rate, pulmonary inflammation, and lung cell injury. Results suggest that occasional consumer use of this antimicrobial spray product should not be a hazard. However, extended exposure of workers routinely applying this product to surfaces should be avoided. During application, care should be taken to minimize exposure by working under well ventilated conditions and by employing respiratory protection as needed. It would be prudent to avoid exposure to children or those with pre-existing respiratory disease. PMID:22642294

  20. Effect of hydro-alcoholic extract of Rosa damascena on cardiovascular responses in normotensive rat

    PubMed Central

    Baniasad, Amir; Khajavirad, Abolfazl; Hosseini, Mahmoud; Shafei, Mohammad Naser; Aminzadah, Saeed; Ghavi, Mahmoud

    2015-01-01

    Objective: Rosa damascena mill L. (R. damascena) is a well-known plant with fragrant effects. Several therapeutic effects of this plant on respiratory, gastrointestinal and nervous systems have been reported. It is also suggested to have beneficial effect on cardiovascular system especially blood pressure regulation. The present study was carried out to evaluate acute cardiovascular effect of hydro-alcoholic extract of R. damascena. Materials and Methods: Thirty-two male Wistar rats were randomly divided into four groups (n= 8 for each group). After anesthesia, a catheter was inserted into the femoral artery and blood pressure and heart rate (HR) were continuously recorded by a power lab system. Animals received three doses of hydro-alcoholic extract (250, 500, and 1000 mg/kg) via peritoneal (i.p). After 30 min, systolic blood pressure (SBP), mean arterial pressure (MAP) and HR were recorded and maximal changes were compared to control group. Results: Injection of all doses of the extract did not significantly change HR compare to control group. The SBP, dose dependently, was decreased by all doses of the extract and the maximal response was significant compared to saline group (p<0.01 to p<0.001). Different doses of the extract also dose-dependently decreased maximal changes of MAP responses compared to control group. The effect of higher doses of the extract on SBP and MAP was significant compared to lower doses (p<0.05 to p<0.01). Conclusion: This study provides evidence of a hypotensive effect of hydro-alcoholic extract of R. damascena with no significant effect on HR. Therefore, R. damascena is suggested to have beneficial effect to control blood pressure. However, it needs to be more investigated. PMID:26442758

  1. WISE-2005: Integrative Cardiovascular Responses with LBNP during 60-Day Bed Rest in Women

    NASA Technical Reports Server (NTRS)

    Hughson, R. L.; Kerbeci, P.; Arbeille, Ph.; Mattar, L.; Shoemaker, J. K.

    2005-01-01

    During 2005, 24 women will take part in the Women International Space-simulation for Exploration (WISE). In this paper we report on the first phase that studied 4 Exercise (EX+LBNP), 4 nutrition (NUT), and 4 no countermeasure control (CON) subjects. The EX+LBNP group completed regular exercise on a treadmill inside LBNP, flywheel resistive exercise and static periods of LBNP, and had recovery days. The NUT group received daily protein supplements. Integrative cardiovascular responses were obtained and here we report data for heart rate during LBNP, blood volume and angiotensin 11. LBNP was applied at 0, -10, -20 and -30 mmHg for 2-minutes for each stage. Blood was sampled prebed rest and on HDT-60. After 60-days head down bed rest, HR in the CON group increased by 6.1+/-2.8 bpm at rest and by 20.7+/-5.0 bpm at -30 mmHg LBNP. The EX+LBNP group had increases of 3.6+/-5.6 and 11.6+/-5.4 bpm, while the NUT group HR increased 2.6+/-3.1 and 9.4+/-3.6 bpm. The EX+LBNP group had almost no change in blood volume or plasma angiotensin II from pre-bed rest to HDT60, while both the CON and NUT groups had larger increases in plasma volume and almost double concentrations of angiotensin II. These data show a positive effect in the EX+LBNP group on the heart rate response as well as an unexpected possible benefit in the NUT group. Further studies are required to confirm possible cardiovascular benefits of the protein supplement.

  2. Xenobiotics Produce Distinct Metabolomic Responses in Zebrafish Larvae (Danio rerio).

    PubMed

    Huang, Susie S Y; Benskin, Jonathan P; Chandramouli, Bharat; Butler, Heather; Helbing, Caren C; Cosgrove, John R

    2016-06-21

    Sensitive and quantitative protocols for characterizing low-dose effects are needed to meet the demands of 21st century chemical hazard assessment. To test the hypothesis that xenobiotic exposure at environmentally relevant concentrations produces specific biochemical fingerprints in organisms, metabolomic perturbations in zebrafish (Danio rerio) embryo/larvae were measured following 24 h exposures to 13 individual chemicals covering a wide range of contaminant classes. Measured metabolites (208 in total) included amino acids, biogenic amines, fatty acids, bile acids, sugars, and lipids. The 96-120 h post-fertilization developmental stage was the most appropriate model for detecting xenobiotic-induced metabolomic perturbations. Metabolomic fingerprints were largely chemical- and dose-specific and were reproducible in multiple exposures over a 16-month period. Furthermore, chemical-specific responses were detected in the presence of an effluent matrix; importantly, in the absence of morphological response. In addition to improving sensitivity for detecting biological responses to low-level xenobiotic exposures, these data can aid the classification of novel contaminants based on the similarity of metabolomic responses to well-characterized "model" compounds. This approach is clearly of use for rapid, sensitive, and specific analyses of chemical effect on organisms, and can supplement existing methods, such as the Zebrafish Embryo Toxicity assay (OECD TG236), with molecular-level information. PMID:27232715

  3. Particle-induced pulmonary acute phase response may be the causal link between particle inhalation and cardiovascular disease

    PubMed Central

    Saber, Anne T; Jacobsen, Nicklas R; Jackson, Petra; Poulsen, Sarah Søs; Kyjovska, Zdenka O; Halappanavar, Sabina; Yauk, Carole L; Wallin, Håkan; Vogel, Ulla

    2014-01-01

    Inhalation of ambient and workplace particulate air pollution is associated with increased risk of cardiovascular disease. One proposed mechanism for this association is that pulmonary inflammation induces a hepatic acute phase response, which increases risk of cardiovascular disease. Induction of the acute phase response is intimately linked to risk of cardiovascular disease as shown in both epidemiological and animal studies. Indeed, blood levels of acute phase proteins, such as C-reactive protein and serum amyloid A, are independent predictors of risk of cardiovascular disease in prospective epidemiological studies. In this review, we present and review emerging evidence that inhalation of particles (e.g., air diesel exhaust particles and nanoparticles) induces a pulmonary acute phase response, and propose that this induction constitutes the causal link between particle inhalation and risk of cardiovascular disease. Increased levels of acute phase mRNA and proteins in lung tissues, bronchoalveolar lavage fluid and plasma clearly indicate pulmonary acute phase response following pulmonary deposition of different kinds of particles including diesel exhaust particles, nanoparticles, and carbon nanotubes. The pulmonary acute phase response is dose-dependent and long lasting. Conversely, the hepatic acute phase response is reduced relative to lung or entirely absent. We also provide evidence that pulmonary inflammation, as measured by neutrophil influx, is a predictor of the acute phase response and that the total surface area of deposited particles correlates with the pulmonary acute phase response. We discuss the implications of these findings in relation to occupational exposure to nanoparticles. How to cite this article: WIREs Nanomed Nanobiotechnol 2014, 6:517–531. doi: 10.1002/wnan.1279 PMID:24920450

  4. Glucose-responsive insulin-producing cells from stem cells.

    PubMed

    Kaczorowski, David J; Patterson, Ethan S; Jastromb, William E; Shamblott, Michael J

    2002-01-01

    Recent success with immunosuppression following islet cell transplantation offers hope that a cell transplantation treatment for type 1 (juvenile) diabetes may be possible if sufficient quantities of safe and effective cells can be produced. For the treatment of type 1 diabetes, the two therapeutically essential functions are the ability to monitor blood glucose levels and the production of corresponding and sufficient levels of mature insulin to maintain glycemic control. Stem cells can replicate themselves and produce cells that take on more specialized functions. If a source of stem cells capable of yielding glucose-responsive insulin-producing (GRIP) cells can be identified, then transplantation-based treatment for type 1 diabetes may become widely available. Currently, stem cells from embryonic and adult sources are being investigated for their ability to proliferate and differentiate into cells with GRIP function. Human embryonic pluripotent stem cells, commonly referred to as embryonic stem (ES) cells and embryonic germ (EG) cells, have received significant attention owing to their broad capacity to differentiate and ability to proliferate well in culture. Their application to diabetes research is of particular promise, as it has been demonstrated that mouse ES cells are capable of producing cells able to normalize glucose levels of diabetic mice, and human ES cells can differentiate into cells capable of insulin production. Cells with GRIP function have also been derived from stem cells residing in adult organisms, here referred to as endogenous stem cell sources. Independent of source, stem cells capable of producing cells with GRIP function may provide a widely available cell transplantation treatment for type 1 diabetes. PMID:12469358

  5. The cardiovascular and endocrine responses to voluntary and forced diving in trained and untrained rats

    PubMed Central

    DiNovo, Karyn. M.; Connolly, Tiffanny M.

    2010-01-01

    The mammalian diving response, consisting of apnea, bradycardia, and increased total peripheral resistance, can be modified by conscious awareness, fear, and anticipation. We wondered whether swim and dive training in rats would 1) affect the magnitude of the cardiovascular responses during voluntary and forced diving, and 2) whether this training would reduce or eliminate any stress due to diving. Results indicate Sprague-Dawley rats have a substantial diving response. Immediately upon submersion, heart rate (HR) decreased by 78%, from 453 ± 12 to 101 ± 8 beats per minute (bpm), and mean arterial pressure (MAP) decreased 25%, from 143 ± 1 to 107 ± 5 mmHg. Approximately 4.5 s after submergence, MAP had increased to a maximum 174 ± 3 mmHg. Blood corticosterone levels indicate trained rats find diving no more stressful than being held by a human, while untrained rats find swimming and diving very stressful. Forced diving is stressful to both trained and untrained rats. The magnitude of bradycardia was similar during both voluntary and forced diving, while the increase in MAP was greater during forced diving. The diving response of laboratory rats, therefore, appears to be dissimilar from that of other animals, as most birds and mammals show intensification of diving bradycardia during forced diving compared with voluntary diving. Rats may exhibit an accentuated antagonism between the parasympathetic and sympathetic branches of the autonomic nervous system, such that in the autonomic control of HR, parasympathetic activity overpowers sympathetic activity. Additionally, laboratory rats may lack the ability to modify the degree of parasympathetic outflow to the heart during an intense cardiorespiratory response (i.e., the diving response). PMID:19923359

  6. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress.

    PubMed

    Wawrzyniak, Andrew J; Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-05-01

    Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = -.009, SE = .005, p = .09) and diastolic (B = -.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = -.007, SE = .003, p = .03) and impaired vagal tone (B = -.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses. PMID:26894967

  7. Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

    PubMed Central

    Hamer, Mark; Steptoe, Andrew; Endrighi, Romano

    2016-01-01

    Abstract Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses. PMID:26894967

  8. Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle

    PubMed Central

    2012-01-01

    Background Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS). Methods We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 μg/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 μL) injection into the 4th V. Results Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. Conclusion We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity. PMID:22463380

  9. Extended Producer Responsibility and Product Stewardship for Tobacco Product Waste

    PubMed Central

    Curtis, Clifton; Collins, Susan; Cunningham, Shea; Stigler, Paula; Novotny, Thomas E

    2015-01-01

    This paper reviews several environmental principles, including Extended Producer Responsibility (EPR), Product Stewardship (PS), the Polluter Pays Principle (PPP), and the Precautionary Principle, as they may apply to tobacco product waste (TPW). The review addresses specific criteria that apply in deciding whether a particular toxic product should adhere to these principles; presents three case studies of similar approaches to other toxic and/or environmentally harmful products; and describes 10 possible interventions or policy actions that may help prevent, reduce, and mitigate the effects of TPW. EPR promotes total lifecycle environmental improvements, placing economic, physical, and informational responsibilities onto the tobacco industry, while PS complements EPR, but with responsibility shared by all parties involved in the tobacco product lifecycle. Both principles focus on toxic source reduction, post-consumer take-back, and final disposal of consumer products. These principles when applied to TPW have the potential to substantially decrease the environmental and public health harms of cigarette butts and other TPW throughout the world. TPW is the most commonly littered item picked up during environmental, urban, and coastal cleanups globally. PMID:26457262

  10. The Genetic Response to Short-term Interventions Affecting Cardiovascular Function: Rationale and Design of the HAPI Heart Study

    PubMed Central

    Mitchell, Braxton D.; McArdle, Patrick F.; Shen, Haiqing; Rampersaud, Evadnie; Pollin, Toni I.; Bielak, Lawrence F.; Jaquish, Cashell; Douglas, Julie A.; Roy-Gagnon, Marie-Hélène; Sack, Paul; Naglieri, Rosalie; Hines, Scott; Horenstein, Richard B.; Chang, Yen-Pei C.; Post, Wendy; Ryan, Kathleen A.; Brereton, Nga Hong; Pakyz, Ruth E.; Sorkin, John; Damcott, Coleen M.; O’Connell, Jeffrey R.; Mangano, Charles; Corretti, Mary; Vogel, Robert; Herzog, William; Weir, Matthew R.; Peyser, Patricia A.; Shuldiner, Alan R.

    2008-01-01

    Background The etiology of cardiovascular disease (CVD) is multifactorial. Efforts to identify genes influencing CVD risk have met with limited success to date, likely due to the small effect sizes of common CVD risk alleles and the presence of gene by gene and gene by environment interactions. Methods The Heredity and Phenotype Intervention (HAPI) Heart Study was initiated in 2002 to measure the cardiovascular response to four short-term interventions affecting cardiovascular risk factors and to identify the genetic and environmental determinants of these responses. The measurements included blood pressure responses to the cold pressor stress test and to a high salt diet, triglyceride excursion in response to a high fat challenge, and response in platelet aggregation to aspirin therapy. Results The interventions were carried out in 868 relatively healthy Amish adults from large families. The heritabilities of selected response traits for each intervention ranged from 8–38%, suggesting that some of the variation associated with response to each intervention can be attributed to the additive effects of genes. Conclusions Identifying these response genes may identify new mechanisms influencing CVD and may lead to individualized preventive strategies and improved early detection of high-risk individuals. PMID:18440328

  11. Mindfulness may both moderate and mediate the effect of physical fitness on cardiovascular responses to stress: a speculative hypothesis

    PubMed Central

    Demarzo, Marcelo M. P.; Montero-Marin, Jesús; Stein, Phyllis K.; Cebolla, Ausiàs; Provinciale, Jaime G.; García-Campayo, Javier

    2014-01-01

    The psychological construct of mindfulness refers to an awareness that emerges by intentionally paying attention to the present experience in a non-judgmental or evaluative way. This particular quality of awareness has been associated to several indicators of physical and psychological health, and can be developed using mindfulness-based interventions (MBIs), and therefore MBIs have been successfully applied as preventive and complementary interventions and therapies in medicine and psychology. Together with quiet sitting and lying meditation practices, mindful physical exercises such as “mindful walking” and “mindful movement” are key elements in MBIs and couple muscular activity with an internally directed focus, improving interoceptive attention to bodily sensations. In addition, MBIs seem to share similar mechanisms with physical fitness (PF) by which they may influence cardiovascular responses to stress. Based on these facts, it is feasible to raise the question of whether physical training itself may induce the development of that particular quality of awareness associated with mindfulness, or if one's dispositional mindfulness (DM) (the tendency to be more mindful in daily life) could moderate the effects of exercise on cardiovascular response to stress. The role of mindfulness as a mediator or moderator of the effect of exercise training on cardiovascular responses to stress has barely been studied. In this study, we have hypothesized pathways (moderation and mediation) by which mindfulness could significantly influence the effects of PF on cardiovascular responses to stress and discussed potential practical ways to test these hypotheses. PMID:24723891

  12. Susceptibility of the aging Brown Norway rat to carbaryl, an anti-cholinesterase-based insecticide: Thermoregulatory and cardiovascular responses.

    EPA Science Inventory

    The proportion of aged in the United States is projected to expand markedly for the next several decades. Hence, the U.S.EPA is assessing if the aged are more susceptible to environmental toxicants. The thermoregulatory and cardiovascular responses of young adult, mature adult, a...

  13. Cardiovascular responses in humans to experimental chewing of gums of different consistencies.

    PubMed

    Farella, M; Bakke, M; Michelotti, A; Marotta, G; Martina, R

    1999-10-01

    Although the cardiovascular effects of exercise have been extensively investigated in man, little attention has been paid to such responses to jaw muscle activity. The aim here was to investigate the general cardiovascular effects of chewing activity in a single-blind, cross-over design. Ten healthy individuals performed one of the following chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a bolus. Unilateral chewing of gum or empty chewing was performed for 20 min on the participant's most convenient chewing side at a constant rate of 80 cycles/min. In each session, heart rate and arterial blood pressure were recorded together with electromyographic activity in the masseter and anterior temporalis muscles on the chewing side. Ratings of perceived masticatory fatigue were recorded with visual analogue scales. The heart rate and blood pressure were significantly increased (ANOVA; p < or= 0.01) during the chewing tasks and the increases were, in parallel with the muscle activity, more pronounced the harder the gum. With the very hard gum, heart rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was 11 mmHg (1.5kPa) higher. The perceived fatigue was proportional to the level of muscle activity. After 10 min of recovery from exercise, heart rate and arterial blood pressures were slightly but still significantly elevated. The results demonstrate that chewing is associated with general circulatory effects proportional to the bolus resistance. PMID:10530916

  14. Cardiovascular regulation in humans in response to oscillatory lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Levenhagen, D. K.; Evans, J. M.; Wang, M.; Knapp, C. F.

    1994-01-01

    The frequency response characteristics of human cardiovascular regulation during hypotensive stress have not been determined. We therefore exposed 10 male volunteers to seven frequencies (0.004-0.1 Hz) of oscillatory lower body negative pressure (OLBNP; 0-50 mmHg). Fourier spectra of arterial pressure (AP), central venous pressure (CVP), stroke volume (SV), cardiac output (CO), heart rate (HR), and total peripheral resistance (TPR) were determined and first harmonic mean, amplitude, and phase angles with respect to OLBNP are presented. AP was relatively well regulated as demonstrated by small oscillations in half amplitude (3.5 mmHg) that were independent of OLBNP frequency and similar to unstressed control spectra. Due to the biomechanics of the system, the magnitudes of oscillations in calf circumference (CC) and CVP decreased with increasing frequency; therefore, we normalized responses by these indexes of the fluid volume shifted. The ratios of oscillations in AP to oscillations in CC increased by an order of magnitude, whereas oscillations in CVP to oscillations in CC and oscillations in AP to oscillations in CVP both tripled between 0.004 and 0.1 Hz. Therefore, even though the amount of fluid shifted by OLBNP decreased with increasing frequency, the magnitude of both CVP and AP oscillations per volume of fluid shifted increased (peaking at 0.08 Hz). The phase relationships between variables, particularly the increasing lags in SV and TPR, but not CVP, indicated that efferent responses with lags of 5-6 s could account for the observed responses. We conclude that, at frequencies below 0.02 Hz, the neural system of humans functioned optimally in regulating AP; OLBNP-induced decreases in SV (by as much as 50%) were counteracted by appropriate oscillations in HR and TPR responses. As OLBNP frequency increased, SV, TPR, and HR oscillations increasingly lagged the input and became less optimally timed for AP regulation.

  15. Effective Bolus Dose of Sufentanil to Attenuate Cardiovascular Responses in Laryngoscopic Double-Lumen Endobronchial Intubation

    PubMed Central

    Choi, Byung-Hee; Lee, Yong-Cheol

    2016-01-01

    Background Sufentanil is a potent opioid analgesic frequently used in clinical anesthesia. Double-lumen endobronchial intubation induces profound cardiovascular responses in comparison with ordinary endotracheal intubation because of the larger tube diameter and direct irritation of the carina. Objectives The purpose of this study was to determine the effective bolus dose of sufentanil to attenuate hemodynamic changes in response to laryngoscopic double-lumen endobronchial intubation. Patients and Methods We randomly assigned 72 patients aged 18 - 65 years and with an American Society of Anesthesiologists physical status of 1 or 2 to one of four sufentanil dose groups: NS, S0.1, S0.2, or S0.3. The respective doses for the groups were as follows: normal saline, 0.1 mcg/kg of sufentanil, 0.2 mcg/kg of sufentanil, and 0.3 mcg/kg of sufentanil. Blood pressure and heart rate were recorded during the pre-anesthesia period at baseline, pre-intubation, immediate post-intubation, and every minute during 5 minutes after intubation. Results Baseline mean arterial pressures in the NS, S0.1, S0.2, and S0.3 groups were 89.8 ± 12.1, 89.2 ± 10.9, 88.8 ± 13.6, and 90.7 ± 11.1, respectively. At immediate post-intubation, the mean arterial pressures in the NS, S0.1, S0.2, and S0.3 groups were 129.7 ± 14.7, 120.7 ± 14.2, 120.8 ± 17.2, and 96.7 ± 10.4, respectively. At immediate post-intubation, the mean arterial pressure in the NS, S0.1, and S0.2 groups significantly increased from baseline (P < 0.001), but the S0.3 group showed no difference. In the time point comparison at immediate post- intubation, the S0.3 group had a significantly lower mean arterial pressure than did the NS, S0.1, and S0.2 groups (P < 0.001). Conclusions We found that 0.3 mcg/kg of sufentanil attenuates cardiovascular responses to double-lumen endobronchial intubation without adverse effects. PMID:27252903

  16. Cerebro- and Cardio-vascular Responses to Energy Drink in Young Adults: Is there a Gender Effect?

    PubMed Central

    Monnard, Cathríona R.; Montani, Jean-Pierre; Grasser, Erik K.

    2016-01-01

    Background and Purpose: Energy drinks (EDs) are suspected to induce potential adverse cardiovascular effects and have recently been shown to reduce cerebral blood flow velocity (CBFV) in young, healthy subjects. Gender differences in CBFV in response to EDs have not previously been investigated, despite the fact that women are more prone to cardiovascular disturbances such as neurocardiogenic syncope than men. Therefore, the aim of this study was to explore gender differences in cerebrovascular and cardiovascular responses to EDs. Methods: We included 45 subjects in a retrospective analysis of pooled data from two previous randomized trials carried out in our laboratory with similar protocols. Beat-to-beat blood pressure, impedance cardiography, transcranial Doppler, and end-tidal carbon dioxide (etCO2) measurements were made for at least 20 min baseline and for 80 min following the ingestion of 355 mL of a sugar-sweetened ED. Gender and time differences in cerebrovascular and cardiovascular parameters were investigated. Results: CBFV was significantly reduced in response to ED, with the greatest reduction observed in women compared with men (−12.3 ± 0.8 vs. −9.7 ± 0.8%, P < 0.05). Analysis of variance indicated significant time (P < 0.01) and gender × time (P < 0.01) effects. The percentage change in CBFV in response to ED was independent of body weight and etCO2. No significant gender difference in major cardiovascular parameters in response to ED was observed. Conclusions: ED ingestion reduced CBFV over time, with a greater reduction observed in women compared with men. Our results have potential implications for women ED consumers, as well as high-risk individuals. PMID:27559316

  17. A Computational Model for Thrombus Formation in Response to Cardiovascular Implantable Devices

    NASA Astrophysics Data System (ADS)

    Horn, John; Ortega, Jason; Maitland, Duncan

    2014-11-01

    Cardiovascular implantable devices elicit complex physiological responses within blood. Notably, alterations in blood flow dynamics and interactions between blood proteins and biomaterial surface chemistry may lead to the formation of thrombus. For some devices, such as stents and heart valves, this is an adverse outcome. For other devices, such as embolic aneurysm treatments, efficient blood clot formation is desired. Thus a method to study how biomedical devices induce thrombosis is paramount to device development and optimization. A multiscale, multiphysics computational model is developed to predict thrombus formation within the vasculature. The model consists of a set of convection-diffusion-reaction partial differential equations for blood protein constituents involved in the progression of the clotting cascades. This model is used to study thrombus production from endovascular devices with the goal of optimizing the device design to generate the desired clotting response. This work was performed in part under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Dietary Methionine Restriction in Mice Elicits an Adaptive Cardiovascular Response to Hyperhomocysteinemia

    PubMed Central

    Ables, Gene P.; Ouattara, Amadou; Hampton, Thomas G.; Cooke, Diana; Perodin, Frantz; Augie, Ines; Orentreich, David S.

    2015-01-01

    Dietary methionine restriction (MR) in rodents increased lifespan despite higher heart-to-body weight ratio (w/w) and hyperhomocysteinemia, which are symptoms associated with increased risk for cardiovascular disease. We investigated this paradoxical effect of MR on cardiac function using young, old, and apolipoprotein E-deficient (ApoE-KO) mice. Indeed, MR animals exhibited higher heart-to-body weight ratio (w/w) and hyperhomocysteinemia with a molecular pattern consistent with cardiac stress while maintaining the integrity of cardiac structure. Baseline cardiac function, which was measured by non-invasive electrocardiography (ECG), showed that young MR mice had prolonged QRS intervals compared with control-fed (CF) mice, whereas old and ApoE-KO mice showed similar results for both groups. Following β-adrenergic challenge, responses of MR mice were either similar or attenuated compared with CF mice. Cardiac contractility, which was measured by isolated heart retrograde perfusion, was similar in both groups of old mice. Finally, the MR diet induced secretion of cardioprotective hormones, adiponectin and fibroblast growth factor 21 (FGF21), in MR mice with concomitant alterations in cardiac metabolic molecular signatures. Our findings demonstrate that MR diet does not alter cardiac function in mice despite the presence of hyperhomocysteinemia because of the adaptive responses of increased adiponectin and FGF21 levels. PMID:25744495

  19. EFFECTS OF AEROBIC CONDITIONING ON CARDIOVASCULAR SYMPATHETIC RESPONSE TO AND RECOVERY FROM CHALLENGE

    PubMed Central

    Lindgren, M; Alex, C; Shapiro, PA; McKinley, PS; Brondolo, EN; Myers, MM; Choi, CJ; Lopez-Pintado, S; Sloan, RP

    2013-01-01

    Objective Exercise has widely-documented cardioprotective effects but the mechanisms behind these effects are still poorly understood. Here, we test the hypothesis that aerobic training lowers cardiovascular sympathetic responses to and speeds recovery from challenge. Methods We conducted a randomized controlled trial contrasting aerobic versus strength training on indices of cardiac (pre-ejection period, PEP) and vascular (low-frequency blood pressure variability, LF-BPV) sympathetic responses to and recovery from psychological and orthostatic challenge in 149 young, healthy and sedentary adults. Results Aerobic and strength training did not alter PEP or LF-BPV reactivity to or recovery from challenge. Conclusions These findings, from a large randomized controlled trial using an intent-to-treat design, show that moderate aerobic exercise training has no effect on PEP and LF BPV reactivity to or recovery from psychological or orthostatic challenge. In healthy young adults, the cardioprotective effects of exercise training are unlikely to be mediated by changes in sympathetic activity. PMID:23889039

  20. Body size at birth and cardiovascular response to and recovery from mental stress in children.

    PubMed

    Feldt, K; Räikkönen, K; Pyhälä, R; Jones, A; Phillips, D I W; Eriksson, J G; Pesonen, A K; Heinonen, K; Järvenpää, A-L; Strandberg, T E; Kajantie, E

    2011-04-01

    Cardiovascular (CV) response to mental stress, a predictor of CV disease risk, may be determined already in utero. However, the underlying mechanisms remain unclear, and previous studies have used adult subjects and neglected CV recovery. We investigated 147 girls and 136 boys aged 8 years who underwent the Trier Social Stress Test for children to determine whether body size at birth is associated with CV activity. Blood pressure (BP), electrocardiogram and impedance-derived indices were recorded and analyzed from continuous measurements using Vasotrac APM205A and Biopac MP150 systems. Among girls, lower birth weight was associated with lower baseline systolic BP (SBP) and diastolic BP (DBP) values (1.9 mm Hg and 1.5 mm Hg per 1 s.d. birth weight for gestational age, respectively), higher SBP and DBP response to mental stress (1.6 mm Hg and 1.1 mm Hg per 1 s.d. birth weight for gestational age, respectively), slower BP recovery and overall higher cardiac sympathetic activity. In contrast, among boys lower birth weight was associated with higher baseline levels of SBP (2.1 mm Hg per 1 s.d. birth weight for gestational age) and total peripheral resistance (TPR), overall lower cardiac sympathetic activity, lower TPR response to mental stress and a more rapid BP and cardiac sympathetic recovery. In boys, the associations with baseline levels and cardiac sympathetic activity became significant only after adjusting for current body size. These sex-specific results suggest that individual differences in childhood CV response to and recovery from mental stress may have prenatal origins. This phenomenon may be important in linking smaller body size at birth to adult CV disease. PMID:20535142

  1. Antihypertensive treatment with verapamil and amlodipine. Their effect on the functional autonomic and cardiovascular stress responses.

    PubMed

    Nazzaro, P; Manzari, M; Merlo, M; Triggiani, R; Scarano, A M; Lasciarrea, A; Pirrelli, A

    1995-09-01

    Many biological and psychological factors induce haemodynamic and extra-cardiovascular functional changes mediated by the autonomic nervous system. Pharmacological blood pressure reduction, as a neurovegetative stimulus, can change the arousal of the sympathetic nervous system. We evaluated the effects of two calcium channel blockers, verapamil and amlodipine, both administered as monotherapies, upon the sympathetic stress response in 23 randomized mild-to-moderate essential hypertensives (161 +/- 2/98 +/- 1 mmHg). Patients performed four stress tests (mental arithmetic, colour word Stroop, cold pressor and handgrip) while extracardiovascular and haemodynamic functions were assessed non-invasively at every heart beat, during baseline, stress and recovery phases. The sympathetic response was evaluated by computing the 'area-under-the-curve' (value x time) measured during the psychophysiological session. The session was repeated at run-in, after placebo and during treatment. After one month's treatment, baseline blood pressure was significantly reduced in patients treated with amlodipine (139 +/- 1/84 +/- 1 mmHg; P < 0.001) and verapamil (140 +/- 2/85 +/- 1 mmHg; P < 0.001). The emotional arousal (frontalis muscular contraction, skin conductance) was unchanged, but the cutaneous vascular response was reduced (P < 0.05) in patients treated with verapamil. No changes in systolic or diastolic blood pressure were detectable, but amlodipine increased the heart rate response (P < 0.05). In contrast, verapamil reduced the heart rate (P < 0.05) without depressing the cardiac output response, which was increased with amlodipine (P < 0.05). Total vascular resistance was significantly (P < 0.001) reduced with both the treatments. Consequently, functional cardiac load, expressed by pressure-rate product and cardiac power, was significantly enhanced with amlodipine and reduced with verapamil. In conclusion, the abnormal sympathetic stress response, which characterizes the

  2. [Influence of the practice of meditation on the cardiovascular response in the perception and cognitive reassessment emotiogenic stimulus].

    PubMed

    Pavlov, S V; Reva, N V; Loktev, K V; Korenek, V V; Aftanas, L

    2015-03-01

    This study examines the effects of meditation on cardiovascular activity during affective image processing. 22 meditators and 20 controls were shown affective images and were asked either to attend to the images or to down-regulate negative affect (for negative images) or to up-regulate positive affect (for positive images) while continuous cardiovascular activity were recorded. During natural viewing meditators manifested identical pre-stimulus total peripheral resistance (TPR) for all images, whereas controls exhibited greatest,pre-stimulus TPR for negative images and reduced it only in the emotion regulation condition. No between-group differences were revealed for natural viewing of positive images, whereas up-regulation was associated with greater cardiac activation in meditators. The results provide a contribution to the understanding of the mechanisms responsible for the beneficial influence of meditation on cardiovascular risk factors. PMID:26016329

  3. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

    PubMed Central

    2012-01-01

    Background It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. Purpose To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). Methods 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Results Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. Conclusions In comparison to the established hyper hydrating Cr

  4. Effects of exercise and weight loss on mental stress-induced cardiovascular responses in individuals with high blood pressure.

    PubMed

    Georgiades, A; Sherwood, A; Gullette, E C; Babyak, M A; Hinderliter, A; Waugh, R; Tweedy, D; Craighead, L; Bloomer, R; Blumenthal, J A

    2000-08-01

    The purpose of this study was to determine the effects of exercise and weight loss on cardiovascular responses during mental stress in mildly to moderately overweight patients with elevated blood pressure. Ninety-nine men and women with high normal or unmedicated stage 1 to stage 2 hypertension (systolic blood pressure 130 to 179 mm Hg, diastolic blood pressure 85 to 109 mm Hg) underwent a battery of mental stress tests, including simulated public speaking, anger recall interview, mirror trace, and cold pressor, before and after a 6-month treatment program. Subjects were randomly assigned to 1 of 3 treatments: (1) aerobic exercise, (2) weight management combining aerobic exercise with a behavioral weight loss program, or (3) waiting list control group. After 6 months, compared with control subjects, participants in both active treatment groups had lower levels of systolic blood pressure, diastolic blood pressure, total peripheral resistance, and heart rate at rest and during mental stress. Compared with subjects in the control group, subjects in the exercise and weight management groups also had greater resting stroke volume and cardiac output. Diastolic blood pressure was lower for the weight management group than for the exercise-only group during all mental stress tasks. These results demonstrate that exercise, particularly when combined with a weight loss program, can lower both resting and stress-induced blood pressure levels and produce a favorable hemodynamic pattern resembling that targeted for antihypertensive therapy. PMID:10948073

  5. Clinical phenotype clustering in cardiovascular risk patients for the identification of responsive metabotypes after red wine polyphenol intake.

    PubMed

    Vázquez-Fresno, Rosa; Llorach, Rafael; Perera, Alexandre; Mandal, Rupasri; Feliz, Miguel; Tinahones, Francisco J; Wishart, David S; Andres-Lacueva, Cristina

    2016-02-01

    This study aims to evaluate the robustness of clinical and metabolic phenotyping through, for the first time, the identification of differential responsiveness to dietary strategies in the improvement of cardiometabolic risk conditions. Clinical phenotyping of 57 volunteers with cardiovascular risk factors was achieved using k-means cluster analysis based on 69 biochemical and anthropometric parameters. Cluster validation based on Dunn and Figure of Merit analysis for internal coherence and external homogeneity were employed. k-Means produced four clusters with particular clinical profiles. Differences on urine metabolomic profiles among clinical phenotypes were explored and validated by multivariate orthogonal signal correction partial least-squares discriminant analysis (OSC-PLS-DA) models. OSC-PLS-DA of (1)H-NMR data revealed that model comparing "obese and diabetic cluster" (OD-c) against "healthier cluster" (H-c) showed the best predictability and robustness in terms of explaining the pairwise differences between clusters. Considering these two clusters, distinct groups of metabolites were observed following an intervention with wine polyphenol intake (WPI; 733 equivalents of gallic acid/day) per 28days. Glucose was significantly linked to OD-c metabotype (P<.01), and lactate, betaine and dimethylamine showed a significant trend. Tartrate (P<.001) was associated with wine polyphenol intervention (OD-c_WPI and H-c_WPI), whereas mannitol, threonine methanol, fucose and 3-hydroxyphenylacetate showed a significant trend. Interestingly, 4-hydroxyphenylacetate significantly increased in H-c_WPI compared to OD-c_WPI and to basal groups (P<.05)-gut microbial-derived metabolite after polyphenol intake-, thereby exhibiting a clear metabotypic intervention effect. Results revealed gut microbiota responsive phenotypes to wine polyphenols intervention. Overall, this study illustrates a novel metabolomic strategy for characterizing interindividual responsiveness to dietary

  6. Dose-response relationship of the cardiovascular adaptation to endurance training in healthy adults: how much training for what benefit?

    PubMed

    Iwasaki, Ken-Ichi; Zhang, Rong; Zuckerman, Julie H; Levine, Benjamin D

    2003-10-01

    Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease. PMID:12832429

  7. Particle-Induced Pulmonary Acute Phase Response Correlates with Neutrophil Influx Linking Inhaled Particles and Cardiovascular Risk

    PubMed Central

    Saber, Anne Thoustrup; Lamson, Jacob Stuart; Jacobsen, Nicklas Raun; Ravn-Haren, Gitte; Hougaard, Karin Sørig; Nyendi, Allen Njimeri; Wahlberg, Pia; Madsen, Anne Mette; Jackson, Petra; Wallin, Håkan; Vogel, Ulla

    2013-01-01

    Background Particulate air pollution is associated with cardiovascular disease. Acute phase response is causally linked to cardiovascular disease. Here, we propose that particle-induced pulmonary acute phase response provides an underlying mechanism for particle-induced cardiovascular risk. Methods We analysed the mRNA expression of Serum Amyloid A (Saa3) in lung tissue from female C57BL/6J mice exposed to different particles including nanomaterials (carbon black and titanium dioxide nanoparticles, multi- and single walled carbon nanotubes), diesel exhaust particles and airborne dust collected at a biofuel plant. Mice were exposed to single or multiple doses of particles by inhalation or intratracheal instillation and pulmonary mRNA expression of Saa3 was determined at different time points of up to 4 weeks after exposure. Also hepatic mRNA expression of Saa3, SAA3 protein levels in broncheoalveolar lavage fluid and in plasma and high density lipoprotein levels in plasma were determined in mice exposed to multiwalled carbon nanotubes. Results Pulmonary exposure to particles strongly increased Saa3 mRNA levels in lung tissue and elevated SAA3 protein levels in broncheoalveolar lavage fluid and plasma, whereas hepatic Saa3 levels were much less affected. Pulmonary Saa3 expression correlated with the number of neutrophils in BAL across different dosing regimens, doses and time points. Conclusions Pulmonary acute phase response may constitute a direct link between particle inhalation and risk of cardiovascular disease. We propose that the particle-induced pulmonary acute phase response may predict risk for cardiovascular disease. PMID:23894396

  8. Physiologic Responses Produced by Active and Passive Personal Cooling Vests

    NASA Technical Reports Server (NTRS)

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Luna, Bernadette

    2000-01-01

    Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to document and compare the subjects' response to three cooling vests in their recommended configurations. The Life Enhancement Tech (LET) lightweight active cooling vest with cap, the MicroClimate Systems Change of Phase garment (MCS), and the Steele Vest were each used to cool the chest regions of 12 male and 8 female Healthy subjects (21 to 69 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approx. 22 C), were tested for 60 min. with one of the cooling garments. The LET active garment had an initial coolant fluid inlet temperature of 60 F, and was ramped down to 50 F. Oral, right and left ear canal temperatures were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. For men, all three vests had similar, significant cooling effects. Decreases in the average rectal temperature, oral temperature, and ear canal temperatures were approximately 0.2 C, 0.2 C and 0.1 C, respectively. In contrast to the men, the female subjects wearing the MCS and Steel vests had similar cooling responses in which the core temperature remained elevated and oral and ear canal temperatures did not drop. The LET active garment cooled most of the female subjects in this study; rectal, oral and ear temperature decreased about 0.2 C, 0.3 C and 0.3 C, respectively. These results show that the garment configurations tested do not elicit a similar thermal response in all subjects. A gender difference is evident. The LET active garment configuration was most effective in decreasing temperatures of the female subjects; the MCS

  9. Renal and cardiovascular responses to water immersion in trained runners and swimmers

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.; Tatro, D. L.; Rogan, R. B.

    1993-01-01

    The purpose of this study was to determine if fluid-electrolyte, renal, hormonal, and cardiovascular responses during and after multi-hour water immersion were associated with aerobic training. Additionally, we compared these responses in those who trained in a hypogravic versus a 1-g environment. Seventeen men comprised three similarly aged groups: six long-distance runners, five competitive swimmers, and six untrained control subjects. Each subject underwent 5 h of immersion in water [mean (SE)] 36.0 (0.5) degrees C to the neck. Immediately before and at each hour of immersion, blood and urine samples were collected and analyzed for sodium (Na), potassium, osmolality, and creatinine (Cr). Plasma antidiuretic hormone and aldosterone were also measured. Hematocrits were used to calculate relative changes in plasma volume (% delta Vpl). Heart rate response to submaximal cycle ergometer exercise (35% peak oxygen uptake) was measured before and after water immersion. Water immersion induced significant increases in urine flow, Na clearance (CNa), and a 3-5% decrease in Vpl. Urine flow during immersion was greater (P < 0.05) in runners [2.4 (0.4) ml.min-1] compared to controls [1.3 (0.1) ml.min-1]. However, % delta Vpl, CCr, CNa and CH2O during immersion were not different (P > 0.05) between runners, swimmers, and controls. After 5 h of immersion, there was an increase (P < 0.05) in submaximal exercise heart rate of 9 (3) and 10 (3) beats.min-1 in both runners and controls, respectively, but no change (P > 0.05) was observed in swimmers.(ABSTRACT TRUNCATED AT 250 WORDS).

  10. Cardiovascular responses evoked from the nicotine-sensitive area on the ventral surface of the medulla oblongata in the cat.

    PubMed Central

    Guertzenstein, P G; Lopes, O U

    1984-01-01

    Experiments were carried out in cats anaesthetized with chloralose, (a) to examine the effect on blood pressure, heart rate and respiratory frequency produced by topical application of leptazol, nicotine and sodium pentobarbitone to the ventral surface of the medulla at an area around the rootlets of the XII cranial nerve, and (b) to study the role of this area in some cardiovascular reflexes. Leptazol applied uni- or bilaterally to this area produced hypotension, bradycardia and bradypnoea. The area from which leptazol produced these effects was localized 3-6 mm lateral to the mid line and 5-9 mm caudal to the lower border of the trapezoid bodies. When comparing the effects of leptazol and nicotine applied to this area it was found that in concentrations that produced similar falls in arterial blood pressure and heart rate leptazol produced a much stronger bradypnoea than nicotine. The hypotension produced by leptazol was mainly due to inhibition of sympathetic vasomotor tone since it was little affected by section of the vagi and by atropine given intravenously. Bilateral application of sodium pentobarbitone produced a small hypertension, tachycardia and pronounced tachypnoea. Unilateral application of sodium pentobarbitone had no effect by itself but inhibited the effects of leptazol applied to the same site. Cardiovascular reflexes produced by sinus nerve stimulation, by increased sinus pressure or by injections of veratridine into a vein or into the left ventricle of the heart were potentiated by topical application of leptazol to the ventral surface and depressed by the topical application of sodium pentobarbitone. The chemoreceptor reflex, produced by retrograde injections of lobeline into the lingual artery, was partially affected by topical application of sodium pentobarbitone: the evoked bradycardia was attenuated but the tachypnoea and hypertension were not affected. These results suggest that this medullary area on the ventral surface of the medulla

  11. Response rate in the Study of Cardiovascular Risks in Adolescents - ERICA.

    PubMed

    Silva, Thiago Luiz Nogueira da; Klein, Carlos Henrique; Souza, Amanda de Moura; Barufaldi, Laura Augusta; Abreu, Gabriela de Azevedo; Kuschnir, Maria Cristina Caetano; Vasconcellos, Mauricio Teixeira Leite de; Bloch, Katia Vergetti

    2016-02-01

    OBJECTIVE To describe the response rate and characteristics of people who either took part or not in from the Study of Cardiovascular Risks in Adolescents (ERICA) , according to information subsets. METHODS ERICA is a school-based, nation-wide investigation with a representative sample of 12 to 17-year-old adolescents attending public or private schools in municipalities with over 100,000 inhabitants in Brazil. Response rate of eligible subjects were calculated according to macro-regions, sex, age, and type of school (public or private). We also calculated the percentages of replacement schools in comparison with the ones originally selected as per the sample design, according to the types of schools in the macro-regions. The subjects and non-subjects were compared according to sex, age, and average body mass indices (kg/m2). RESULTS We had 102,327 eligible adolescents enrolled in the groups drawn. The highest percentage of complete information was obtained for the subset of the questionnaire (72.9%). Complete information regarding anthropometric measurements and the ones from the questionnaire were obtained for 72.0% of the adolescents, and the combination of these data with the 24-hour dietary recall were obtained for 70.3% of the adolescents. Complete information from the questionnaire plus biochemical blood evaluation data were obtained for 52.5% of the morning session adolescents (selected for blood tests). The response percentage in private schools was higher than the one in public schools for most of the combination of information. The ratio of older and male adolescents non-participants was higher than the ratio among participants. CONCLUSIONS The response rate for non-invasive procedures was high. The response rate for blood collection - an invasive procedure that requires a 12-hour fasting period and the informed consent form from legal guardians - was lower. The response rate observed in public schools was lower than in the private ones, and that may

  12. Response rate in the Study of Cardiovascular Risks in Adolescents – ERICA

    PubMed Central

    da Silva, Thiago Luiz Nogueira; Klein, Carlos Henrique; Souza, Amanda de Moura; Barufaldi, Laura Augusta; Abreu, Gabriela de Azevedo; Kuschnir, Maria Cristina Caetano; de Vasconcellos, Mauricio Teixeira Leite; Bloch, Katia Vergetti

    2016-01-01

    ABSTRACT OBJECTIVE To describe the response rate and characteristics of people who either took part or not in from the Study of Cardiovascular Risks in Adolescents (ERICA) , according to information subsets. METHODS ERICA is a school-based, nation-wide investigation with a representative sample of 12 to 17-year-old adolescents attending public or private schools in municipalities with over 100,000 inhabitants in Brazil. Response rate of eligible subjects were calculated according to macro-regions, sex, age, and type of school (public or private). We also calculated the percentages of replacement schools in comparison with the ones originally selected as per the sample design, according to the types of schools in the macro-regions. The subjects and non-subjects were compared according to sex, age, and average body mass indices (kg/m2). RESULTS We had 102,327 eligible adolescents enrolled in the groups drawn. The highest percentage of complete information was obtained for the subset of the questionnaire (72.9%). Complete information regarding anthropometric measurements and the ones from the questionnaire were obtained for 72.0% of the adolescents, and the combination of these data with the 24-hour dietary recall were obtained for 70.3% of the adolescents. Complete information from the questionnaire plus biochemical blood evaluation data were obtained for 52.5% of the morning session adolescents (selected for blood tests). The response percentage in private schools was higher than the one in public schools for most of the combination of information. The ratio of older and male adolescents non-participants was higher than the ratio among participants. CONCLUSIONS The response rate for non-invasive procedures was high. The response rate for blood collection – an invasive procedure that requires a 12-hour fasting period and the informed consent form from legal guardians – was lower. The response rate observed in public schools was lower than in the private ones, and

  13. Cardiovascular responses of men and women to lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Montgomery, L. D.; Kirk, P. J.; Payne, P. A.; Gerber, R. L.; Newton, S. D.; Williams, B. A.

    1977-01-01

    Changes in blood flow and blood redistribution were measured by impedance plethysmography in the pelvic and leg regions of six male and four female subjects during three 5-min exposures to -20, -40, and -60 mm Hg lower body negative pressure (LBNP). Female subjects demonstrated significantly higher mean heart rate and lower leg blood flow indices than the male subjects during the recumbent control periods. Men had slightly higher mean resting systolic and diastolic blood pressures and higher mean control pelvic blood indices. Women demonstrated significantly less blood pooling in the legs and slightly less in the pelvic region than the men. All of the 18 tests with male subjects at -60 mm Hg were completed without initial signs of syncope, while only two of the tests with women were completed successfully without the subject exhibiting presyncopal conditions. Results indicate that impedance plethysmography can be used to measure segmental cardiovascular responses during LBNP and that females may be less tolerant to -60 mm Hg LBNP than males.

  14. Respiratory and Cardiovascular Response during Electronic Control Device Exposure in Law Enforcement Trainees

    PubMed Central

    VanMeenen, Kirsten M.; Lavietes, Marc H.; Cherniack, Neil S.; Bergen, Michael T.; Teichman, Ronald; Servatius, Richard J.

    2013-01-01

    Objective: Law enforcement represents a large population of workers who may be exposed to electronic control devices (ECDs). Little is known about the potential effect of exposure to these devices on respiration or cardiovascular response during current discharge. Methods: Participants (N = 23) were trainees exposed to 5 s of an ECD (Taser X26®) as a component of training. Trainees were asked to volitionally inhale during exposure. Respiratory recordings involved a continuous waveform recorded throughout the session including during the exposure period. Heart rate was calculated from a continuous pulse oximetry recording. Results: The exposure period resulted in the cessation of normal breathing patterns in all participants and in particular a decrease in inspiratory activity. No significant changes in heart rate during ECD exposure were found. Conclusion: This is the first study to examine breathing patterns during ECD exposure with the resolution to detect changes over this discrete period of time. In contrast to reports suggesting respiration is unaffected by ECDs, present evidence suggests that voluntary inspiration is severely compromised. There is no evidence of cardiac disruption during ECD exposure. PMID:23616772

  15. The Impact of Abdominal Obesity Status on Cardiovascular Response to the Mediterranean Diet

    PubMed Central

    Bédard, Alexandra; Dodin, Sylvie; Corneau, Louise; Lemieux, Simone

    2012-01-01

    We investigated the impact of abdominal obesity status on the cardiovascular response to a fully controlled 4-week isoenergetic Mediterranean diet (MedDiet). Thirty-eight abdominally obese individuals (waist circumference >102 cm in men and >88 cm in women) and thirty-one nonabdominally obese individuals were recruited and studied before and after the MedDiet. All analyses were adjusted for the slight decrease in body weight, which occurred during the MedDiet (mean: 0.9 ± 1.2 kg). A group by time interaction was noted for waist circumference (P = 0.02), abdominally obese subjects showing a significant decrease and nonabdominally obese subjects a nonsignificant increase (resp., −1.1 and +0.3%). The MedDiet resulted in decreases in total cholesterol, LDL-C, HDL-C, apolipoprotein B, A-1, and A-2, total cholesterol/HDL-C ratio, LDL-C/HDL-C ratio, and systolic and diastolic blood pressure (time effect: P < 0.05). For all variables related to glucose/insulin homeostasis, no change was observed except for a decrease in 2 h glucose concentrations (time effect: P = 0.03). No group by time interaction was observed in any of the metabolic variables studied. Results from our study suggest that the adoption of the MedDiet leads to beneficial metabolic effects, irrespective of the abdominal obesity status. PMID:23133745

  16. Effects of head cooling on cardiovascular and body temperature responses during submaximal exercise.

    PubMed

    Watanuki, S

    1993-11-01

    Cardiovascular and body temperature responses during submaximal exercise (25% and 50% VO2max) were investigated using female subjects (n = 6) in two separate experiments; one with head cooling and heating and the other with torso heating with and without head cooling. To supply the heat load, a liquid conditioned cap and vest were used. In the first experiment, a significant decrease in heart rate, oxygen intake (VO2) and cardiac output (Q) at relative work intensity of 50% VO2max was observed by head cooling. These results show that head cooling is very effective to reduce the physiological strain. In the second experiment, Q as a function of VO2 during torso heating was decreased by head cooling. However, the tympanic membrane temperature during head cooling at 15 degrees C was significantly higher than that at 20 degrees C and it was almost the same level with torso heating without head cooling. The results suggest that excess head cooling is not beneficial in terms of improving the body heat dissipation. PMID:8123182

  17. Policy trends of extended producer responsibility in Malaysia.

    PubMed

    Agamuthu, P; Victor, Dennis

    2011-09-01

    This paper seeks to examine the provisions for extended producer responsibility (EPR) within the Malaysian environmental and waste management policies and to determine its existing practice and future prospects in Malaysia. Malaysian waste generation has been increasing drastically where solid waste generation was estimated to increase from about 9.0 million tonnes in 2000 to about 10.9 million tonnes in 2010, to about 12.8 million tonnes in 2015 and finally to about 15.6 million tonnes in 2020. Malaysian e-waste was estimated to be about 652 909 tonnes in 2006 and was estimated to increase to about 706 000 tonnes in 2010 and finally to about 1.2 million tonnes in 2020. The projected increasing generation of both solid waste and scheduled wastes is expected to burden the country's resources and environment in managing these wastes in a sustainable manner. The concept of EPR is provided for in the Malaysia waste management system via the Environmental Quality Act 1974 and the Solid Waste and Public Cleansing Management Act 2007. However, these provisions in the policy are generic in nature without relevant regulations to enable its enforcement and as such the concept of EPR still remains on paper whereas the existing practice of EPR in Malaysia is limited through voluntary participation. In conclusion, policy trends of EPR in Malaysia seem to indicate that Malaysia may be embarking on the path towards EPR through the enactment of an EPR regulation. PMID:21771873

  18. Cardiovascular reflex responses to cutaneous and visceral stimuli in spinal man

    PubMed Central

    Corbett, J. L.; Frankel, H. L.; Harris, P. J.

    1971-01-01

    1. A study has been made of the effects of pinprick and a cold pack applied to the skin above and below the level of denervation, deep inspiration, squeezing the chest, and bladder percussion in non-bedridden patients with chronic, closed, complete, localized transection of the cervical spinal cord. Variables studied were blood pressure, heart rate, calf blood flow, hand blood flow and occluded vein pressure in the hand and foot. 2. Cutaneous stimuli above the lesion, mental arithmetic and noise from gunshot produced no response. 3. Pinprick and cold applied below the lesion usually produced an increase in mean arterial pressure, little change in pulse pressure or heart rate, clear decreases in calf and hand blood flow, and occasional venoconstriction. 4. Deep inspiration produced an initial rise in blood pressure and heart rate which was sometimes followed by a decrease in one or both. Squeezing the chest usually produced an increase in blood pressure and a decrease in heart rate. Both stimuli caused decreases in calf and hand blood flow and venoconstriction, the latter being more common after squeezing the chest. 5. Bladder percussion produced contraction of the wall of the bladder and this was regularly associated with increased arterial mean and pulse pressures, a decreased heart rate and calf and hand blood flow, and venoconstriction. The responses occurred whether or not the bladder was full and whether or not a rise of intravesical pressure occurred. PMID:5145725

  19. Influence of immune activation and inflammatory response on cardiovascular risk associated with the human immunodeficiency virus

    PubMed Central

    Beltrán, Luis M; Rubio-Navarro, Alfonso; Amaro-Villalobos, Juan Manuel; Egido, Jesús; García-Puig, Juan; Moreno, Juan Antonio

    2015-01-01

    Patients infected with the human immunodeficiency virus (HIV) have an increased cardiovascular risk. Although initially this increased risk was attributed to metabolic alterations associated with antiretroviral treatment, in recent years, the attention has been focused on the HIV disease itself. Inflammation, immune system activation, and endothelial dysfunction facilitated by HIV infection have been identified as key factors in the development and progression of atherosclerosis. In this review, we describe the epidemiology and pathogenesis of cardiovascular disease in patients with HIV infection and summarize the latest knowledge on the relationship between traditional and novel inflammatory, immune activation, and endothelial dysfunction biomarkers on the cardiovascular risk associated with HIV infection. PMID:25609975

  20. Aging alters muscle reflex control of autonomic cardiovascular responses to rhythmic contractions in humans.

    PubMed

    Sidhu, Simranjit K; Weavil, Joshua C; Venturelli, Massimo; Rossman, Matthew J; Gmelch, Benjamin S; Bledsoe, Amber D; Richardson, Russell S; Amann, Markus

    2015-11-01

    We investigated the influence of aging on the group III/IV muscle afferents in the exercise pressor reflex-mediated cardiovascular response to rhythmic exercise. Nine old (OLD; 68 ± 2 yr) and nine young (YNG; 24 ± 2 yr) males performed single-leg knee extensor exercise (15 W, 30 W, 80% max) under control conditions and with lumbar intrathecal fentanyl impairing feedback from group III/IV leg muscle afferents. Mean arterial pressure (MAP), cardiac output, leg blood flow (QL), systemic (SVC) and leg vascular conductance (LVC) were continuously determined. With no hemodynamic effect at rest, fentanyl blockade during exercise attenuated both cardiac output and QL ∼17% in YNG, while the decrease in cardiac output in OLD (∼5%) was significantly smaller with no impact on QL (P = 0.8). Therefore, in the face of similar significant ∼7% reduction in MAP during exercise with fentanyl blockade in both groups, LVC significantly increased ∼11% in OLD, but decreased ∼8% in YNG. The opposing direction of change was reflected in SVC with a significant ∼5% increase in OLD and a ∼12% decrease in YNG. Thus while cardiac output seems to account for the majority of group III/IV-mediated MAP responses in YNG, the impact of neural feedback on the heart may decrease with age and alterations in SVC become more prominent in mediating the similar exercise pressor reflex in OLD. Interestingly, in terms of peripheral hemodynamics, while group III/IV-mediated feedback plays a clear role in increasing LVC during exercise in the YNG, these afferents seem to actually reduce LVC in OLD. These peripheral findings may help explain the limited exercise-induced peripheral vasodilation often associated with aging. PMID:26386110

  1. Genetic variants in serotonin and corticosteroid systems modulate neuroendocrine and cardiovascular responses to intense stress.

    PubMed

    Taylor, Marcus K; Larson, Gerald E; Lauby, Melissa D Hiller

    2014-08-15

    Common variants in serotonin and corticosteroid receptor genes influence human stress in laboratory settings. Little is known of their combined effects, especially in high stress environments. This study evaluated distinct and combined effects of polymorphisms in the serotonin transporter (5HTTLPRL/S), glucocorticoid receptor (Bcl1C/G), and mineralocorticoid (-2C/G) receptor genes on adrenocortical and cardiovascular responses to intense, realistic stress. One hundred and forty four healthy, active-duty military men were studied before, during, and 24h after a stressful 12-day survival course. Dependent variables were cortisol, heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP). 5HTTLPR SS carriers revealed higher overall cortisol concentrations than L carriers (p=.022). 5HTTLPR L carriers demonstrated higher stress-induced HR than non-carriers (SS) yet rebounded to a lower recovery value (p=.026), while Bcl1 G carriers showed higher mean stress-induced HR than non-carriers (CC) (p=.047). For DBP, 5HTTLPR S carriers showed higher overall values than non-carriers (LL) (p=.043), Bcl1 GG were higher than C carriers (p=.039), and -2C/G G carriers exceeded non-carriers (CC) (p=.028). A "high" composite genotype group revealed substantially higher overall cortisol concentrations than a "low" composite genotype group (p<.001), as was the case for DBP (p=.037). This study revealed a synergistic effect of common polymorphisms on the acute stress response in healthy men. Pending additional study, these findings may have implications for drug discovery, gene therapy, and stress inoculation strategies. PMID:24821403

  2. Cardiovascular and Perceptual Responses to an Ultraendurance Channel Swim: A Case Study.

    PubMed

    Judelson, Daniel A; Bagley, James R; Schumacher, Jennifer M; Wiersma, Lenny D

    2015-09-01

    Ultraendurance open water swimming presents unique physiological challenges. This case study aimed to describe cardiovascular and perceptual responses during a successful solo channel swim. Investigators followed a female swimmer's Catalina Channel (32.2 km) crossing, monitoring water temperature (T(water)) and air temperature (T(air)), distance remaining (DR), average velocity, and heart rate (HR(swim)) at regular intervals. Every 24 minutes, the swimmer reported perceived pain (on a scale of 0-10), rating of perceived exertion (RPE [scale of 6-20]), perceived thermal sensation (scale 0-8), and thirst (scale 1-9). Data are presented as mean ± SD where applicable. The participant finished in 9 hours, 2 minutes, and 48 seconds; T(water) averaged 19.1 ± 0.4ºC, and T(air) averaged 18.6 ± 0.9ºC. Her HR(swim) ranged from 148 to 155 beats/min, and thermal sensation ranged from 3 to 4. Pain inconsistently varied from 0 to 5 during the swim. The RPE remained between 12 and 14 for the first 8 hours, but increased dramatically near the end (reaching 18). Thirst sensation steadily increased throughout the swim, again reaching maximal values on completion. Physiologically and statistically significant correlations existed between thirst and DR (r = -0.905), RPE and HR(swim) (r = 0.741), RPE and DR (r = -0.694), and pain and DR (r = -0.671). The primary findings were that, despite fluctuations in perceptual stressors, the swimmer maintained a consistent exercise intensity as indicated by HR(swim); and during ultraendurance swimming, pain, RPE, and thirst positively correlated with distance swum. We hope these findings aid in the preparation and performance of future athletes by providing information on what swimmers may expect during an ultraendurance attempt and by increasing the understanding of physiological and perceptual responses during open water swimming. PMID:25819111

  3. Impact of age on the cardiovascular response to dynamic upright exercise in healthy men and women.

    PubMed

    Fleg, J L; O'Connor, F; Gerstenblith, G; Becker, L C; Clulow, J; Schulman, S P; Lakatta, E G

    1995-03-01

    To examine whether age differentially modifies the physiological response to exercise in men and women, we performed gated radionuclide ventriculography with measurement of left ventricular volumes at rest and during peak upright cycle exercise in 200 rigorously screened healthy sedentary volunteers (121 men and 79 women) aged 22-86 yr from the Baltimore Longitudinal Study of Aging. At rest in the sitting position, age-associated declines in heart rate (HR) and increases in systolic blood pressure occurred in both sexes. Whereas resting cardiac index (CI) and total systemic vascular resistance (TSVR) in men did not vary with age, in women resting CI decreased 16% and TSVR increased 46% over the six-decade age span. Men, but not women, demonstrated an age-associated increase of approximately 20% in sitting end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and stroke volume index over this age span. Peak cycle work rate declined with age approximately 40% in both sexes, but at any age it was greater in men than in women even after normalization for body weight. At peak effort, ejection fraction (EF), HR, and CI were reduced similarly with age while ESVI and TSVR were increased in both sexes; EDVI increased 35% with age and stroke work index (SWI) rose 19% in men, but neither was related to age in women; and stroke volume index did not vary with age in either sex. When hemodynamics were expressed as the change from rest to peak effort as an index of cardiovascular reserve function, both sexes demonstrated age-associated increases in EDVI and ESVI and reductions in EF, HR, and CI. However, the exercise-induced reduction in ESVI and the increases in EF, CI, and SWI from rest were greater in men than in women. Thus, age and gender each have a significant impact on the cardiac response to exhaustive upright cycle exercise. PMID:7775334

  4. Whole body plethysmography reveals differential ventilatory responses to ozone in rat models of cardiovascular disease.

    PubMed

    Dye, Janice A; Ledbetter, Allen D; Schladweiler, Mette C; Costa, Daniel L; Kodavanti, Urmila P

    2015-01-01

    To elucidate key factors of host susceptibility to air pollution, healthy and cardiovascular (CV)-compromised rats were exposed to air or ozone (O3) at 0.25, 0.5, or 1.0 ppm for 4 h. We hypothesized that rat strains with the least cardiac reserve would be most prone to develop significant health effects. Using flow whole body plethysmography (FWBP), ventilatory responses in healthy 3-month-old male rats [i.e. Wistar-Kyoto (WKY), Wistar (WIS), and Sprague-Dawley (SD) strains] were compared with hypertensive [i.e. spontaneously hypertensive (SH), fawn-hooded-hypertensive (FHH), and SH-stroke-prone (SHSP)] strains and obese [i.e. SH-heart failure-prone (SHHF) and JCR:LA-cp, atherosclerosis-prone (JCR)] strains. SH were slower to acclimate to the FWBP chambers. At 0-h post-air-exposure, SHSP and SHHF exhibited hyperpnea, indicative of cardiopulmonary insufficiency. At 0-h-post-O3, all but one strain showed significant concentration-dependent decreases in minute volume [MV = tidal volume (TV) × breathing frequency]. Comparing air with 1.0 ppm responses, MV declined 20-27% in healthy, 21-42% in hypertensive, and 33% in JCR rats, but was unchanged in SHHF rats. Penh increased significantly in all strains, with disproportionate increases in "responder" WKY and FHH strains. By 20 h, most changes had resolved, although Penh remained elevated in WKY, SH, and SHSP. Based on the effective dose estimates (O3 ppm × h × MV), the most CV-compromised (SHSP and SHHF) strains received significantly greater O3 lung deposition (25% and 40%, respectively). Data support epidemiologic associations that individuals with cardiopulmonary insufficiency are at greater risk for urban pollutant exposure due, in part, to enhanced lung deposition and exacerbation of hypoxia and pathophysiologic processes of heart failure. PMID:26667328

  5. Whole Body Plethysmography Reveals Differential Ventilatory Responses to Ozone in Rat Models of Cardiovascular Disease

    EPA Science Inventory

    Increasingly, urban air pollution is recognized as an important determinant of cardiovascular disease. Host susceptibility to air pollution can vary due to genetic predisposition and underlying disease. To elucidate key factors of host ...

  6. Acrolein Inhalation Alters Arterial Blood Gases and Triggers Carotid Body Mediated Cardiovascular Responses in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases risk of cardiovascular morbidity and mortality, especially in individuals with underlying cardiopulmonary disease. While the mechanisms accounting for these effects are unclear, several epidemiological studies have reported decreases in oxygen ...

  7. Pulmonary Transcriptional Response to Ozone in Healthy and Cardiovascular Compromised Rat Models

    EPA Science Inventory

    The genetic cardiovascular disease (CVD) and associated metabolic impairments can influence the lung injury from inhaled pollutants. We hypothesized that comparative assessment of global pulmonary expression profile of healthy and CVD-prone rat models will provide mechanistic ins...

  8. Fundus photography as a convenient tool to study microvascular responses to cardiovascular disease risk factors in epidemiological studies.

    PubMed

    De Boever, Patrick; Louwies, Tijs; Provost, Eline; Int Panis, Luc; Nawrot, Tim S

    2014-01-01

    The microcirculation consists of blood vessels with diameters less than 150 µm. It makes up a large part of the circulatory system and plays an important role in maintaining cardiovascular health. The retina is a tissue that lines the interior of the eye and it is the only tissue that allows for a non-invasive analysis of the microvasculature. Nowadays, high-quality fundus images can be acquired using digital cameras. Retinal images can be collected in 5 min or less, even without dilatation of the pupils. This unobtrusive and fast procedure for visualizing the microcirculation is attractive to apply in epidemiological studies and to monitor cardiovascular health from early age up to old age. Systemic diseases that affect the circulation can result in progressive morphological changes in the retinal vasculature. For example, changes in the vessel calibers of retinal arteries and veins have been associated with hypertension, atherosclerosis, and increased risk of stroke and myocardial infarction. The vessel widths are derived using image analysis software and the width of the six largest arteries and veins are summarized in the Central Retinal Arteriolar Equivalent (CRAE) and the Central Retinal Venular Equivalent (CRVE). The latter features have been shown useful to study the impact of modifiable lifestyle and environmental cardiovascular disease risk factors. The procedures to acquire fundus images and the analysis steps to obtain CRAE and CRVE are described. Coefficients of variation of repeated measures of CRAE and CRVE are less than 2% and within-rater reliability is very high. Using a panel study, the rapid response of the retinal vessel calibers to short-term changes in particulate air pollution, a known risk factor for cardiovascular mortality and morbidity, is reported. In conclusion, retinal imaging is proposed as a convenient and instrumental tool for epidemiological studies to study microvascular responses to cardiovascular disease risk factors. PMID

  9. Effects of heart rate variability biofeedback on cardiovascular responses and autonomic sympathovagal modulation following stressor tasks in prehypertensives.

    PubMed

    Chen, S; Sun, P; Wang, S; Lin, G; Wang, T

    2016-02-01

    Autonomic dysfunction is implicated in prehypertension, and previous studies have suggested that therapies that improve modulation of sympathovagal balance, such as biofeedback and slow abdominal breathing, are effective in patients with prehypertension at rest. However, considering that psychophysiological stressors may be associated with greater cardiovascular risk in prehypertensives, it is important to investigate whether heart rate variability biofeedback (HRV-BF) results in equivalent effects on autonomic cardiovascular responses control during stressful conditions in prehypertensives. A total of 32 college students with prehypertension were enrolled and randomly assigned to HRV-BF (n=12), slow abdominal breathing (SAB, n=10) or no treatment (control, n=10) groups. Then, a training experiment consisting of 15 sessions was employed to compare the effect of each intervention on the following cardiovascular response indicators before and after intervention: heart rate (HR); heart rate variability (HRV) components; blood volume pulse amplitude (BVPamp); galvanic skin response; respiration rate (RSP); and blood pressure. In addition, the cold pressor test and the mental arithmetic challenge test were also performed over two successive days before and after the invention as well as after 3 months of follow-up. A significant decrease in HR and RSP and a significant increase in BVPamp were observed after the HRV-BF intervention (P<0.001). For the HRV analysis, HRV-BF significantly reduced the ratio of low-frequency power to high-frequency power (the LF/HF ratio, P<0.001) and increased the normalized high-frequency power (HFnm) (P<0.001) during the stress tests, and an added benefit over SAB by improving HRV was also observed. In the 3-month follow-up study, similar effects on RSP, BVPamp, LF/HF and HFnm were observed in the HRV-BF group compared with the SAB group. HRV-BF training contributes to the beneficial effect of reducing the stress-related cardiovascular

  10. The Implicit Positive and Negative Affect Test: Validity and Relationship with Cardiovascular Stress-Responses

    PubMed Central

    van der Ploeg, Melanie M.; Brosschot, Jos F.; Thayer, Julian F.; Verkuil, Bart

    2016-01-01

    Self-report, i.e., explicit, measures of affect cannot fully explain the cardiovascular (CV) responses to stressors. Measuring affect beyond self-report, i.e., using implicit measures, could add to our understanding of stress-related CV activity. The Implicit Positive and Negative Affect Test (IPANAT) was administered in two studies to test its ecological validity and relation with CV responses and self-report measures of affect. In Study 1 students (N = 34) viewed four film clips inducing anger, happiness, fear, or no emotion, and completed the IPANAT and the Positive And Negative Affect Scale at baseline and after each clip. Implicit negative affect (INA) was higher and implicit positive affect (IPA) was lower after the anger inducing clip and vice versa after the happiness inducing clip. In Study 2 students performed a stressful math task with (n = 14) or without anger harassment (n = 15) and completed the IPANAT and a Visual Analog Scale as an explicit measure afterwards. Systolic (SBP), diastolic (DBP) blood pressure, heart rate (HR), heart rate variability (HRV), and total peripheral resistance (TPR) were recorded throughout. SBP and DBP were higher and TPR was lower in the harassment condition during the task with a prolonged effect on SBP and DBP during recovery. As expected, explicit negative affect (ENA) was higher and explicit positive affect (EPA) lower after harassment, but ENA and EPA were not related to CV activity. Although neither INA nor IPA differed between the tasks, during both tasks higher INA was related to higher SBP, lower HRV and lower TPR and to slower recovery of DBP after both tasks. Low IPA was related to slower recovery of SBP and DBP after the tasks. Implicit affect was not related to recovery of HR, HRV, and TPR. In conclusion, the IPANAT seems to respond to film clip-induced negative and positive affect and was related to CV activity during and after stressful tasks. These findings support the theory that implicitly measured affect

  11. The Implicit Positive and Negative Affect Test: Validity and Relationship with Cardiovascular Stress-Responses.

    PubMed

    van der Ploeg, Melanie M; Brosschot, Jos F; Thayer, Julian F; Verkuil, Bart

    2016-01-01

    Self-report, i.e., explicit, measures of affect cannot fully explain the cardiovascular (CV) responses to stressors. Measuring affect beyond self-report, i.e., using implicit measures, could add to our understanding of stress-related CV activity. The Implicit Positive and Negative Affect Test (IPANAT) was administered in two studies to test its ecological validity and relation with CV responses and self-report measures of affect. In Study 1 students (N = 34) viewed four film clips inducing anger, happiness, fear, or no emotion, and completed the IPANAT and the Positive And Negative Affect Scale at baseline and after each clip. Implicit negative affect (INA) was higher and implicit positive affect (IPA) was lower after the anger inducing clip and vice versa after the happiness inducing clip. In Study 2 students performed a stressful math task with (n = 14) or without anger harassment (n = 15) and completed the IPANAT and a Visual Analog Scale as an explicit measure afterwards. Systolic (SBP), diastolic (DBP) blood pressure, heart rate (HR), heart rate variability (HRV), and total peripheral resistance (TPR) were recorded throughout. SBP and DBP were higher and TPR was lower in the harassment condition during the task with a prolonged effect on SBP and DBP during recovery. As expected, explicit negative affect (ENA) was higher and explicit positive affect (EPA) lower after harassment, but ENA and EPA were not related to CV activity. Although neither INA nor IPA differed between the tasks, during both tasks higher INA was related to higher SBP, lower HRV and lower TPR and to slower recovery of DBP after both tasks. Low IPA was related to slower recovery of SBP and DBP after the tasks. Implicit affect was not related to recovery of HR, HRV, and TPR. In conclusion, the IPANAT seems to respond to film clip-induced negative and positive affect and was related to CV activity during and after stressful tasks. These findings support the theory that implicitly measured affect

  12. Comparison of cardiovascular responses to isometric (static) and isotonic (dynamic) exercise tests in chronic atrial fibrillation.

    PubMed

    Akdur, Hülya; Yigit, Zerrin; Arabaci, Umit; Polat, Mine Gülden; Gürses, Hülya Nilgün; Güzelsoy, Deniz

    2002-11-01

    The aim of the present study was to evaluate the tolerance to various exercises by determining the cardiovascular response to static and dynamic exercises in patients with nonvalvular atrial fibrillation. Fifty patients (mean age: 63.6 +/- 10.3 years; male: 25, female: 25) with chronic (more than one year) nonvalvular atrial fibrillation were included in the study. All patients underwent exercise tests, adjusted appropriately according to their symptoms, as dynamic exercise on a Marquette Case 15 device according to a modified Bruce protocol. Heart rate, and systolic and diastolic arterial pressures were measured at rest and at all stages of the exercise; and the heart rate-pressure products were evaluated. A handgrip test was also conducted as static exercise. The measurements were made before, at the 1st, 2nd and 3rd minutes, and in the recovery periods of the exercise. The percent values of the changes of the 1st, 2nd and 3rd minute measurements in relation to the initial values for both exercises were compared. In addition, the maximal responses to the exercise tests and the post exercise values were also compared. For statistical evaluations, the paired Student-t test was used. Heart rate and pressure-heart rate product values obtained at 1, 2, and 3 minutes during the treadmill exercise test were significantly high compared to the handgrip values (P < 0.0001). The arterial systolic and diastolic pressure values in the 1st minute were also significantly higher during the handgrip test (P = 0.0100 and P = 0.0320, respectively). The values of diastolic arterial pressure at the 2nd minute during the handgrip test, and systolic arterial pressure at the 3rd minute during the treadmill test were found to be statistically significant (P = 0.0240, P = 0.0340, respectively). The mean exercise time and MET value during the treadmill exercise test were 7.18 +/- 2.65 minutes and 5.32 +/- 1.38 mL.kg(-1) x dk(-1). respectively. During the recovery period, the 5th minute

  13. Cardiovascular Responses to an Isometric Handgrip Exercise in Females with Prehypertension

    PubMed Central

    Bond, Vernon; Curry, Bryan H.; Adams, Richard G.; Obisesan, Thomas; Pemminati, Sudhakar; Gorantla, Vasavi R.; Kadur, Kishan; Millis, Richard M.

    2016-01-01

    Background: Hypertensive individuals are known to exhibit greater increases in blood pressure during an isometric handgrip exercise (IHE) than their normotensive counterparts. Aim: This study tests the hypothesis that, compared to normotensive individuals, prehypertensive individuals exhibit an exaggerated response to IHE. Materials and Methods: In this study, the effects of IHE were compared in matched prehypertensive vs. normotensive healthy African-American females. Six healthy young adult African–American female university students were screened in a physician's office for blood pressure in the range of prehypertension, systolic blood pressure (SBP) 120–139 mmHg and diastolic blood pressure (DBP) 80–89 mmHg. Six young adult African–American women were also recruited to serve as a healthy normotensive control group with SBP ≤119 mmHg and DBP ≤79 mmHg. Cardiovascular fitness was determined by peak oxygen uptake (VO2 peak) measured during a progressive exercise test. Results: During the handgrip exercise, the prehypertensive group exhibited greater increases in SBP (from 139 ± 6 to 205 ± 11 mmHg, +48%) than the controls (from 132 ± 3 to 145 ± 3 mmHg, +10%); intergroup difference P < 0.001. The prehypertensive group also exhibited greater increases in DBP (from 77 ± 2 to 112 ± 5 mmHg, +46%) compared to the controls (from 72 ± 3 to 78 ± 4 mmHg, +8%); intergroup difference P < 0.001. The increase in systemic vascular resistance was also greater in the prehypertensive group (from 1713 ± 91 to 2807 ± 370 dyne.s.cm-5, +64%) than in the controls (from 1668 ± 80 to 1812 ± 169 dyne.s.cm-5, +9%); intergroup difference P < 0.05. Conclusion: These results suggest that blood pressure measurements performed during IHE may be a useful screening tool in evaluating prehypertensive individuals for antihypertensive treatments. PMID:27500128

  14. Influence of the Flushing Response in the Relationship between Alcohol Consumption and Cardiovascular Disease Risk

    PubMed Central

    Suh, Hae Sun; Kim, Sung Soo; Jung, Jin Gyu; Yoon, Seok Jun; Ahn, Jae Bum

    2014-01-01

    Background The purpose of this study was to examine the relationship between cardiovascular disease risk and alcohol consumption according to facial flushing after drinking among Korean men. Methods The subjects were 1,817 Korean men (non-drinker group, 283 men; drinking-related facial flushing group, 662 men; non-flushing group, 872 men) >30 years who had undergone comprehensive health examinations at the health promotion center of a Chungnam National University Hospital between 2007 and 2009. Alcohol consumption and alcohol-related facial flushing were assessed through a questionnaire. Cardiovascular disease risk was investigated based on the 2008 Framingham Heart Study. With the non-drinker group as reference, logistic regression was used to analyze the relationship between weekly alcohol intake and cardiovascular disease risk within 10 years for the flushing and non-flushing groups, with adjustment for confounding factors such as body mass index, diastolic blood pressure, low density lipoprotein cholesterol, triglycerides, and exercise patterns. Results Individuals in the non-flushing group with alcohol consumption of ≤4 standard drinks (1 standard drink = 14 g of alcohol) per week had significantly lower moderate or high cardiovascular disease risk than individuals in the nondrinker group (adjusted odds ratio, 0.51; 95% confidence interval, 0.37 to 0.71). However, no significant relationship between the drinking amount and cardiovascular disease risk was observed in the flushing group. Conclusion Cardiovascular disease risk is likely lowered by alcohol consumption among non-flushers, and the relationship between the drinking amount and cardiovascular disease risk may differ according to facial flushing after drinking, representing an individual's vulnerability. PMID:25426277

  15. Progress toward Producing Demand-Response-Ready Appliances

    SciTech Connect

    Hammerstrom, Donald J.; Sastry, Chellury

    2009-12-01

    This report summarizes several historical and ongoing efforts to make small electrical demand-side devices like home appliances more responsive to the dynamic needs of electric power grids. Whereas the utility community often reserves the word demand response for infrequent 2 to 6 hour curtailments that reduce total electrical system peak load, other beneficial responses and ancillary services that may be provided by responsive electrical demand are of interest. Historically, demand responses from the demand side have been obtained by applying external, retrofitted, controlled switches to existing electrical demand. This report is directed instead toward those manufactured products, including appliances, that are able to provide demand responses as soon as they are purchased and that require few, or no, after-market modifications to make them responsive to needs of power grids. Efforts to be summarized include Open Automated Demand Response, the Association of Home Appliance Manufacturer standard CHA 1, a simple interface being developed by the U-SNAP Alliance, various emerging autonomous responses, and the recent PinBus interface that was developed at Pacific Northwest National Laboratory.

  16. Effects of cannabidiol and diazepam on behavioral and cardiovascular responses induced by contextual conditioned fear in rats.

    PubMed

    Resstel, Leonardo B M; Joca, Sâmia R L; Moreira, Fabrício A; Corrêa, Fernando M A; Guimarães, Francisco S

    2006-09-25

    Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa that induces anxiolytic-like effects similar to diazepam in animal models of innate aversive behavior. However, the effects of CBD contextual conditioned fear have not been studied. Therefore, the aim of this work was to compare the behavioral and cardiovascular effects of CBD and diazepam, a prototype anxiolytic, in animals submitted to a contextual conditioned fear paradigm. Male Wistar rats were submitted to a 10min conditioning session (six footshocks, 2.5 mA, 3s, delivered at pseudo-random intervals). The behavioral and cardiovascular responses to the context were measured 24h later in a 10 min test session. Diazepam (2.5 mg/kg), FG-7142 (8 mg/kg), a benzodiazepine inverse agonist, or CBD (10 mg/kg) were administered i.p. before the test session. Conditioned rats submitted to the aversive context exhibited more freezing behavior and a larger increase in blood pressure and heart rate as compared to non-conditioned animals. These effects were attenuated by CBD and diazepam in the conditioned animals. These drugs did not have any effect in non-conditioned rats. FG-7142 treatment failed to change the behavioral and cardiovascular responses to the aversive context. In conclusion, the results suggest that CBD has anxiolytic-like properties similar to those of diazepam in a rat model of conditioned fear to context. PMID:16780966

  17. The effects of high-intensity intermittent exercise training on cardiovascular response to mental and physical challenge.

    PubMed

    Heydari, Mehrdad; Boutcher, Yati N; Boutcher, Stephen H

    2013-02-01

    The purpose was to examine the effect of a 12-week exercise intervention on the cardiovascular and autonomic response of males to mental and physical challenge. Thirty four young overweight males were randomly assigned to either an exercise or control group. The exercise group completed a high-intensity intermittent exercise (HIIE) program three times per week for 12weeks. Cardiovascular response to the Stroop task was determined before and after the intervention by assessing heart rate (HR), stroke volume (SV), arterial stiffness, baroreflex sensitivity (BRS), and skeletal muscle blood flow. The exercise group improved their aerobic fitness levels by 17% and reduced their body weight by 1.6kg. Exercisers compared to controls experienced a significant reduction in HR (p<0.001) and a significant increase in SV (p<0.001) at rest and during Stroop and exercise. For exercisers, arterial stiffness significantly decreased at rest and during Stroop (p<0.01), whereas BRS was increased at rest and during Stroop (p<0.01). Forearm blood flow was significantly increased during the first two minutes of Stroop (p<0.05). HIIE induced significant cardiovascular and autonomic changes at rest and during mental and physical challenge after 12weeks of training. PMID:23220158

  18. Cardiovascular and endocrine response to hemorrhage after. cap alpha. /sub 1/-blockade in lambs and ewes

    SciTech Connect

    Block, S.M.; Rose, J.C.; Ernest, J.M.; Flowe, K.; South, S.; Zimmerman, C.

    1987-02-01

    To evaluate the role of the ..cap alpha../sub 1/-adrenergic system in the response to hemorrhage during development, lambs and adult sheep were chronically catheterized and hemorrhaged after pretreatment with prazosin or vehicle. The adults became markedly more hypotensive after ..cap alpha../sub 1/-blockade and hemorrhage than after vehicle and hemorrhage, whereas the lambs were no more hypotensive when hemorrhaged after prazosin. In the adults and the lambs hemorrhage produced elevations in plasma renin activity and arginine vasopressin measured by radioimmunoassay. However, after prazosin, the adults had a far greater increase in arginine vasopressin levels than after vehicle treatment.

  19. Ventral lamina terminalis mediates enhanced cardiovascular responses of rostral ventrolateral medulla neurons during increased dietary salt.

    PubMed

    Adams, Julye M; Bardgett, Megan E; Stocker, Sean D

    2009-08-01

    Increased dietary salt enhances sympathoexcitatory and sympathoinhibitory responses evoked from the rostral ventrolateral medulla (RVLM). The purpose of the present study was to determine whether neurons of the forebrain lamina terminalis (LT) mediated these changes in the RVLM. Male Sprague-Dawley rats with and without LT lesions were fed normal chow and given access to water or 0.9% NaCl for 14 to 15 days. Unilateral injection of l-glutamate into the RVLM produced significantly larger increases in renal sympathetic nerve activity and arterial blood pressure of sham rats ingesting 0.9% NaCl versus water. However, these differences were not observed between ventral LT-lesioned rats drinking 0.9% NaCl versus water. Similar findings were observed when angiotensin II or gamma-aminobutyric acid was injected into the RVLM. Interestingly, a subset of animals drinking 0.9% but with damage restricted to the organum vasculosum of the lamina terminalis did not show enhanced responses to l-glutamate or gamma-aminobutyric acid. In marked contrast, RVLM injection of l-glutamate or gamma-aminobutyric acid produced exaggerated sympathetic nerve activity and arterial blood pressure responses in animals drinking 0.9% NaCl versus water after an acute ventral LT lesion or chronic lesion of the subfornical organ. Additional experiments demonstrated that plasma sodium concentration and osmolality were increased at night in rats ingesting 0.9% NaCl. These findings suggest that neurons of the ventral LT mediate the ability of increased dietary salt to enhance the responsiveness of RVLM sympathetic neurons. PMID:19506102

  20. Do Cardiovascular Responses to Active and Passive Coping Tasks predict Future Blood Pressure over a 10-Month Later?

    PubMed

    Yuenyongchaiwat, Kornanong; Baker, Ian; Maratos, Frankie; Sheffield, David

    2016-01-01

    The study examined whether cardiovascular responses to active or passive coping tasks and single or multiple tasks predicted changes in resting blood pressure (BP) over a ten-month period. Heart rate (HR), BP, cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, and during mental stress tests (mental arithmetic, speech, and cold pressor tasks). A total of 104 eligible participants participated in the initial study, and 77 (74.04%) normotensive adult participants' resting BP were re-evaluated at ten-month follow-up. Regression analyses indicated that after adjustment for baseline BP, initial age, gender, body mass index, family history of cardiovascular disease, and current cigarette smoking, heighted systolic blood pressure (SBP) and HR responses to an active coping task (mental arithmetic) were associated with increased future SBP (ΔR2 = .060, ΔR2 = .045, respectively). Further, aggregated SBP responsivity (over the three tasks) to the predictor models resulted in significant, but smaller increases in ΔR2 accounting for .040 of the variance of follow-up SBP. These findings suggest that cardiovascular responses to active coping tasks predict future SBP. Further, compared with single tasks, the findings revealed that SBP responses to three tasks were less predictive compared to an individual task (i.e., mental arithmetic). Of importance, hemodynamic reactivity (namely CO and TPR) did not predict future BP suggesting that more general psychophysiological processes (e.g., inflammation, platelet aggregation) may be implicated, or that BP, but not hemodynamic reactivity may be a marker of hypertension. PMID:26972632

  1. Central Cardiovascular Responses of Quadriplegic Subjects to Arm Exercise at Varying Levels of Oxygen Uptake.

    ERIC Educational Resources Information Center

    Figoni, Stephen F.

    The purpose of this study was to assess selected central cardiovascular functions of spinal cord injured, quadriplegic subjects at varying levels of oxygen uptake (VO sub 2). Subjects included 11 untrained, male college students with C5, C6, or C7 complete quadriplegia and 11 able-bodied reference subjects. Exercise was performed on a Monark cycle…

  2. CARDIOVASCULAR AND THERMOREGULATORY RESPONSES OF UNRESTRAINED RATS EXPOSED TO FILTERED OR UNFILTERED DIESEL EXHAUST

    EPA Science Inventory

    Diesel exhaust (DE) has been associated with adverse cardiovascular and pulmonary health effects. The relative contributions of the gas-phase and particulate (PM) components of DE are less well understood. We exposed WKY rats with or without implanted radiotransmitters to air or ...

  3. A cardiovascular system model for lower-body negative pressure response

    NASA Technical Reports Server (NTRS)

    Mitchell, B. A., Jr.; Giese, R. P.

    1971-01-01

    Mathematical models used to study complex physiological control systems are discussed. Efforts were made to modify a model of the cardiovascular system for use in studying lower body negative pressure. A computer program was written which allows orderly, straightforward expansion to include exercise, metabolism (thermal stress), respiration, and other body functions.

  4. Community-Responsive Interventions to Reduce Cardiovascular Risk in American Indians

    ERIC Educational Resources Information Center

    Jobe, Jared B.; Adams, Alexandra K.; Henderson, Jeffrey A.; Karanja, Njeri; Lee, Elisa T.; Walters, Karina L.

    2012-01-01

    American Indian and Alaska Native (AI/AN) populations bear a heavy burden of cardiovascular disease (CVD), and they have the highest rates of risk factors for CVD, such as cigarette smoking, obesity, and diabetes, of any U.S. population group. Yet, few randomized controlled trials have been launched to test potential preventive interventions in…

  5. Cardiovascular, endocrine and behavioural responses to suckling and permanent separation in goats

    PubMed Central

    2010-01-01

    down than during earlier nights (P ≤ 0.01 during N1 and N3 and P ≤ 0.05 during N2). Conclusions Suckling elevated plasma cortisol and β-endorphin concentrations in the goats. The intensive vocalisation in the goats after separation, earlier suggested to indicate stress, was not accompanied by cardiovascular or endocrine responses. PMID:20807413

  6. Sympathetic and cardiovascular responses to glossopharyngeal insufflation in trained apnea divers.

    PubMed

    Heusser, Karsten; Dzamonja, Gordan; Breskovic, Toni; Steinback, Craig D; Diedrich, André; Tank, Jens; Jordan, Jens; Dujic, Zeljko

    2010-12-01

    Glossopharyngeal insufflation (lung packing) is a common maneuver among experienced apnea divers by which additional air is pumped into the lungs. It has been shown that packing may compromise cardiovascular homeostasis. We tested the hypothesis that the packing-mediated increase in intrathoracic pressure enhances the baroreflex-mediated increase in muscle sympathetic nerve activity (MSNA) in response to an exaggerated drop in cardiac output (CO). We compared changes in hemodynamics and MSNA (peroneal microneurography) during maximal breath-holds without and with prior moderate packing (0.79 ± 0.40 liters) in 14 trained divers (12 men, 2 women, 26.7 ± 4.5 yr, body mass index 24.8 ± 2.4 kg/m(2)). Packing did not change apnea time (3.8 ± 1.0 vs. 3.8 ± 1.2 min), hemoglobin oxygen desaturation (-17.6 ± 12.3 vs. -18.7 ± 12.8%), or the reduction in CO (1 min: -3.65 ± 1.83 vs. -3.39 ± 1.96 l/min; end of apnea: -2.44 ± 1.33 vs. -2.16 ± 1.44 l/min). On the other hand, packing dampened the early, i.e., 1-min increase in mean arterial pressure (MAP, 1 min: 9.2 ± 8.3 vs. 2.4 ± 11.0 mmHg, P < 0.01) and in total peripheral resistance (relative TPR, 1 min: 2.1 ± 0.5 vs. 1.9 ± 0.5, P < 0.05) but it augmented the concomitant rise in MSNA (1 min: 28.0 ± 11.7 vs. 39.4 ± 12.7 bursts/min, P < 0.001; 32.8 ± 16.4 vs. 43.9 ± 14.8 bursts/100 heart beats, P < 0.01; 3.3 ± 2.1 vs. 4.8 ± 3.2 au/min, P < 0.05). We conclude that the early sympathoactivation 1 min into apnea after moderate packing is due to mechanisms other than excessive reduction in CO. We speculate that lower MAP despite increased MSNA after packing might be explained by vasodilator substances released by the lungs. This idea should be addressed in future studies. PMID:20864558

  7. Influence of CO2 on cardiovascular response to hypoxia in conscious dogs.

    PubMed

    Koehler, R C; McDonald, B W; Krasney, J A

    1980-10-01

    The modulating effect of CO2 on the circulatory response to hypoxia in chronically instrumented conscious dogs was examined over a wide range of arterial partial pressure of O2 [PaO2 (from 80 to 25 Torr)] during a 41-min rebreathing period at three CO2 levels: hypocapnia (from PaCO2 of 32 to 18 Torr), eucapnia (32 Torr), and mild hypercapnia (40 Torr). Eucapnic and hypercapnic hypoxic responses were also measured after sinoaortic denervation (SAD) to assess the arterial chemoreceptor and baroreceptor reflex contributions. Elevating PaCO2 attenuated the tachycardia during hypoxia and produced progressively greater systemic, renal, and splanchnic vasoconstriction before but not after SAD. Vagal block converted the rises in renal and splanchnic flows observed during hypocapnic hypoxia to declines. The increase in left ventricular dP/dtmax was not affected by varying PaCO2 either before or after SAD. Coronary flow increased an additional onefold during hypoxia when PaCO2 was elevated both before and after SAD, but the tension-time indices did not differ significantly. These results indicate that: a) cardiopulmonary vagal afferents effectively counteract chemoreflex-induced vasoconstriction during hypocapnic hypoxia; b) chemoreflex vasoconstriction predominates in the renal and splanchnic beds when PaCO2 is elevated; c) the sinoaortic reflexes restrain the heart rate, but not the contractility response to hypoxia when PaCO2 is increased; and d) the augmented coronary vasodilation produced by CO2 is probably mediated by local CO2-hypoxic interactions. PMID:6775543

  8. Postnatal cardiovascular and metabolic responses to a single intramuscular dose of betamethasone in fetal sheep born prematurely by cesarean section.

    PubMed

    Padbury, J F; Polk, D H; Ervin, M G; Berry, L M; Ikegami, M; Jobe, A H

    1995-11-01

    Although the benefits of antenatal hormone treatment are well accepted, most studies have reported only pulmonary effects. There is evidence of beneficial cardiovascular and metabolic effects in studies using chronically catheterized animals; however because of the route of administration, the results are not directly applicable to clinical strategies. We previously demonstrated significant pulmonary effects in animals treated antenatally with a single, direct fetal, intramuscular injection of glucocorticoids. This study was performed to determine the effects of a single fetal injection of betamethasone (BETA) alone or in combination with thyroxine (T4) on cardiovascular and metabolic responses after preterm birth. Hemodynamic and metabolic responses at birth were determined in fetuses (126-d gestation; term = 150 d) treated with ultrasound-guided intramuscular injections of 0.5 mg/kg BETA (n = 7), BETA plus 60 g/kg T4 (n = 7), or saline (SAL, n = 9). After 48 h, lambs were delivered by cesarean section and studied for 3 h. BETA treatment increased mean arterial blood pressure [56 +/- 6 (SEM) versus 42 +/- 3 mm Hg], heart rate (152 +/- 5 versus 123 +/- 4 beats/min), and cardiac output (467 +/- 17 versus 349 +/- 36 mL/min/kg) versus SAL. Responses of BETA+T4-treated animals were not different from animals treated with BETA alone. Glucose and FFA were similar among all groups. The increase in catecholamine levels normally seen at birth was significantly attenuated in both the BETA and BETA+T4-treated animals. A single, intramuscular injection of glucocorticoids 48 h before delivery improves cardiovascular responses to preterm birth. This effect is not augmented by concomitant administration of T4. PMID:8552438

  9. Evaluation of the ethanol antagonist' Ro15-4513 on cardiovascular and metabolic responses induced by ethanol

    SciTech Connect

    Lerner, M.R.; Gauvin, D.V.; Holloway, F.A.; Wilson, M.F.; Brackett, D.J. Veterans Affairs Medical Center, Oklahoma City, OK )

    1992-02-26

    The putative ethanol antagonist Ro15-4513 has been reported to attenuate many behavioral responses induced by ethanol, including motor coordination, narcosis, ethanol self administration and intake, and anticonvulsant actions. This study was designed to study the effect of Ro15-4513 on cardiovascular and metabolic responses elicited by intragastric ethanol in conscious rats. Four groups of rats were catheterized under enflurane anesthesia and allowed to regain consciousness. Each group was given either 3.2, 10.0, or 32.0 mg/kg Ro15-4513 or equivalent Tween (i.p.) following ethanol. Ro15-4513 had no effect at any concentration on the decreases in mean arterial pressure, cardiac output, central venous pressure, respiration rate, and cardiac stroke volume and the increases in systemic vascular resistance, heart rate, and glucose evoked by the ethanol challenge. Blood alcohol concentrations measured throughout the study were not affected by any concentration of Ro15-4513. These data suggest that even though Ro15-4513 has significant effects on behavioral responses induced by ethanol it has no effect on the cardiovascular and metabolic responses elicited during ethanol intoxication.

  10. Does mental arithmetic before head up tilt have an effect on the orthostatic cardiovascular and hormonal responses?

    NASA Astrophysics Data System (ADS)

    Goswami, Nandu; Lackner, Helmut Karl; Papousek, Ilona; Montani, Jean-Pierre; Jezova, Daniela; Hinghofer-Szalkay, Helmut G.

    2011-05-01

    Passive head up tilt (HUT) and mental arithmetic (MA) are commonly used for providing mental and orthostatic challenges, respectively. In animal experiments, even a single exposure to a stressor has been shown to modify the response to subsequent stress stimulus. We investigated whether MA applied before HUT elicits synergistic responses in orthostatic heart rate (HR), cardiac output (CO), heart rate variability and arterial blood pressure. The 15 healthy young males were subjected to two randomized protocols: (a) HUT and (b) HUT preceded by MA, with sessions randomized and ≥2 weeks apart. Beat to beat continuous hemodynamic variables were measured and saliva samples taken for hormonal assay. HUT alone increased HR from 59±7 (baseline) to 80±10 bpm (mean±SD) and mean blood pressure (MBP) from 88±10 to 91±14 mmHg. HUT results after MA were not different from those with HUT alone. The activity of alpha amylase showed differences during the experiments irrespective of the protocols. We conclude that mental challenge does not affect orthostatic cardiovascular responses when applied before; the timing of mental loading seems to be critical if it is intended to alter cardiovascular responses to upright standing.

  11. Maintenance of safety behaviors via response-produced stimuli.

    PubMed

    Angelakis, Ioannis; Austin, Jennifer L

    2015-11-01

    Animal studies suggest that safety behaviors may be maintained by internally or externally produced safety signals, which function as positive reinforcers. We designed two experiments to test this phenomenon with humans. Participants played a computerized game in which they could earn or lose treasures by clicking on a map. In baseline, losses could be postponed by pressing a pedal that also produced a blue bar at the bottom of the screen. During test conditions, no losses were programmed, and pedal presses turned the bar from yellow to blue (Test 1) or blue to yellow (Test 2). In Experiment 2, new participants were exposed to the same conditions but were given information about the safety of the test environment. In both experiments, participants engaged in high rates of pedal pressing when presses were followed by blue bars, suggesting the bar functioned as a safety signal. We discuss how these findings may relate to safety behaviors commonly observed in certain mental health disorders. PMID:26463997

  12. Possible role of afferent autonomic signals in abdominal organs in anorexic and cardiovascular responses to nicotine injection in rats.

    PubMed

    Yagi, Shintaro; Tanida, Mamoru; Satomi, Jun

    2015-05-27

    Smoking generally causes an increase in nicotine levels in the blood, affecting the brain components, such as the hypothalamus (feeding-related area) or the brain stem (cardiovascular control area). In terms of nicotine transmission to the brain, a new insight that the afferent vagal nerve in the liver is important for sensing increased nicotine levels in the blood and informing the brain was reported in an experiment with rats. However, it has not been clarified whether the afferent autonomic nerve system is implicated in feeding and cardiovascular responses to nicotine. Here, we examined the possible role of afferent autonomic nerve transmission in rats in regulating feeding behavior and cardiovascular functions by nicotine. An intravenous injection of nicotine dose dependently increased the blood pressure (BP) in urethane-anesthetized rats; high nicotine doses also led to an increase in BP in conscious rats. Further, an intravenous injection of nicotine for 3 days reduced food intake and body weight gain in rats. The weight-reducing action of intravenous nicotine was abolished by blocking the afferent sympathetic signals in the abdominal organs, but not the vagal nerve signals. Moreover, the hypertensive action of nicotine was not abolished either by afferent sympathectomy or by vagotomy. Thus, these data suggest that nicotine injected into the vein acts on the afferent sympathetic nerve in the abdominal organs and transmits signals to the brain for reducing body weight, but not for suppressing appetite or increasing BP. PMID:25875474

  13. Cardiovascular, ventilatory and catecholamine responses to maximal dynamic exercise in partially curarized man.

    PubMed Central

    Galbo, H; Kjaer, M; Secher, N H

    1987-01-01

    1. In ten young men the ventilatory, cardiovascular, catecholamine and metabolic responses to maximal dynamic leg exercise on a stationary bicycle were followed during partial neuromuscular blockade with tubocurarine. Maximal exercise was performed when the drug effect was at its maximum as well as during the subsequent reduction in the effect allowing a gradually increasing work intensity. The results were compared with those obtained during submaximal and maximal exercise performed without tubocurarine. Partial neuromuscular blockade decreased hand-grip strength to 41 +/- 1.1% (S.E. of mean) and the maximal work load to 27 +/- 2.4% of control values. Voluntary effort was maximal and the rate of perceived exertion was high at all levels of exercise with tubocurarine indicating a maintained intense central nervous motor command. 2. During maximal action of the drug oxygen uptake was 1.67 +/- 0.11 l/min while only 0.91 +/- 0.13 l/min (P less than 0.01) at the same work intensity without neuromuscular blockade. This difference may reflect a dominant reliance on fast-twitch muscle fibres when work was performed under the influence of tubocurarine. 3. Compared at a given oxygen uptake ventilation was higher during work with tubocurarine than during control exercise (e.g. 55 +/- 4.2 and 40 +/- 2.2 l/min, respectively (P less than 0.01), at a mean oxygen uptake of 1.9 l/min), while heart rate did not differ significantly (146 +/- 4.4 and 139 +/- 3.0 beats/min). With decreasing drug effect both variables increased towards the maximum values of 138 +/- 4.5 l/min and 183 +/- 3.9 beats/min, respectively, achieved in control experiments at an oxygen uptake of 3.8 +/- 0.2 l/min. Like heart rate the mean arterial blood pressure increased with increasing work load and was similar at a given oxygen uptake with and without tubocurarine. 4. During maximal exercise at peak tubocurarine effect plasma adrenaline and noradrenaline concentrations were smaller than during control maximum

  14. Health monitoring of Japanese payload specialist: Autonomic nervous and cardiovascular responses under reduced gravity condition (L-0)

    NASA Technical Reports Server (NTRS)

    Sekiguchi, Chiharu

    1993-01-01

    In addition to health monitoring of the Japanese Payload Specialists (PS) during the flight, this investigation also focuses on the changes of cardiovascular hemodynamics during flight which will be conducted under the science collaboration with the Lower Body Negative Pressure (LBNP) Experiment of NASA. For the Japanese, this is an opportunity to examine firsthand the effects of microgravity of human physiology. We are particularly interested in the adaption process and how it relates to space motion sickness and cardiovascular deconditioning. By comparing data from our own experiment to data collected by others, we hope to understand the processes involved and find ways to avoid these problems for future Japanese astronauts onboard Space Station Freedom and other Japanese space ventures. The primary objective of this experiment is to monitor the health condition of Japanese Payload Specialists to maintain a good health status during and after space flight. The second purpose is to investigate the autonomic nervous system's response to space motion sickness. To achieve this, the function of the autonomic nervous system will be monitored using non-invasive techniques. Data obtained will be employed to evaluate the role of autonomic nervous system in space motion sickness and to predict susceptibility to space motion sickness. The third objective is evaluation of the adaption process of the cardiovascular system to microgravity. By observation of the hemodynamics using an echocardiogram we will gain insight on cardiovascular deconditioning. The last objective is to create a data base for use in the health care of Japanese astronauts by obtaining control data in experiment L-O in the SL-J mission.

  15. Early visual cortical responses produced by checkerboard pattern stimulation.

    PubMed

    Shigihara, Yoshihito; Hoshi, Hideyuki; Zeki, Semir

    2016-07-01

    Visual evoked potentials have been traditionally triggered with flash or reversing checkerboard stimuli and recorded with electroencephalographic techniques, largely but not exclusively in clinical or clinically related settings. They have been crucial in determining the healthy functioning or otherwise of the visual pathways up to and including the cerebral cortex. They have typically given early response latencies of 100ms, the source of which has been attributed to V1, with the prestriate cortex being secondarily activated somewhat later. On the other hand, magnetoencephalographic studies using stimuli better tailored to the physiology of individual, specialized, visual areas have given early latencies of <50ms with the sources localized in both striate (V1) and prestriate cortex. In this study, we used the reversing checkerboard pattern as a stimulus and recorded cortical visual evoked magnetic fields with magnetoencephalography, to establish whether very early responses can be traced to (estimated) in both striate and prestriate cortex, since such a demonstration would enhance considerably the power of this classical approach in clinical investigations. Our results show that cortical responses evoked by checkerboard patterns can be detected before 50ms post-stimulus onset and that their sources can be estimated in both striate and prestriate cortex, suggesting a strong parallel input from the sub-cortex to both striate and prestriate divisions of the visual cortex. PMID:27083528

  16. Exposure Assessment and Inflammatory Response Among Workers Producing Calcium Carbonate Nanomaterials

    NASA Astrophysics Data System (ADS)

    Cui, Ling

    . Modification is thought to be the primary emission source. It is discovered nanoparticles in the size range of 20-300nm dominate in this workplace, which consists of 90-98% of particle counts in the respirable fraction. Based on the sampling results from 2012, there was a strong relationship between number concentration in 5-25um range and the respirable mass concentration (r= 0.908); however, no such correlation was found between number concentration in nanoscale and respirable mass (r= 0.018). The deposited surface area in TB (r=0.66) and alveolar region (r=0.46) was modestly correlated with number concentration of particles in the nanoscale. A reduced FEV1 and increased BP were consistently found among medium-mass exposure compared to low-mass exposure, however no statistical significance was found. When comparing the four exposure metrics, we found number concentration and surface area concentration in general produce effects in similar direction, however opposite to mass concentration. Such observation is consistent with the correlation among these exposure metrics. Airway inflammatory responses presented a dose-response relationship using mass as exposure metric. The concentrations of IL1beta (p =0.043) and IL8 (p=0.008) in sputum among high mass-exposure group were statistically greater than that in low-mass exposure group. It suggested the inflammatory responses were associated with mass concentration of inhaled nanoparticle particles, which are mainly made up by agglomerated form of nanoparticles. At current stage, with limited understanding of the toxicological perspective of nanoparticle, a complete exposure assessment in nanoparticle facility needs to be conducted in both bulk- and nano-form.

  17. The Effect of Ambient Temperature on the Cardiovascular Responses to Microgravity as Simulated by six Degrees Head Down Tilt (HDT)

    NASA Astrophysics Data System (ADS)

    Nangalia, Vishal; Ernsting, John

    Background: To determine the effect of ambient temperature on the thermoregulatory and cardiovascular responses to microgravity as simulated by six degrees head down tilt (HDT). Hypothesis: The thermoregulatory and cardiovascular responses to 6°HDT are unaffected by ambient temperatures between 12° and 32°C. Method: Each of five volunteer subjects (18-24 y.) underwent three separate 6 h exposures in a climatic chamber whilst lying supine with 6°HDT. The ambient temperatures for the first 5 h of the exposure were 12°, 22° and 32°C. At the beginning of the sixth hour, the ambient temperature was either increased or decreased by 10°C depending on the initial temperature. Heart rate, blood pressure, forearm bloodflow, core and skin temperatures, urine output and body weight were measured before, during and after each exposure. Results: Mean arterial pressure was increased in all exposures, though the increase varied with the ambient temperature. Pulse pressure after 5 h HDT increased in the 32°C exposure, remained unchanged at 22°C and decreased at 12°C. The threshold for thermoregulatory increases in forearm vascular conductance was lowered. Core temperature of the body increased in the exposures to 32°C and 22°C. The reduction in body weight (mean 1 kg.) was identical in all exposures whilst the urine output varied with ambient temperature. No significant changes occurred in any variable when the ambient temperature was changed by 10°C at the end of the fifth hour. Conclusions: The cardiovascular responses to 6 h exposure to 6° HDT, are affected by the ambient temperature.

  18. Mathematical Model of Cardiovascular and Metabolic Responses to Umbilical Cord Occlusions in Fetal Sheep.

    PubMed

    Wang, Qiming; Gold, Nathan; Frasch, Martin G; Huang, Huaxiong; Thiriet, Marc; Wang, Xiaogang

    2015-12-01

    Fetal acidemia during labor is associated with an increased risk of brain injury and lasting neurological deficits. This is in part due to the repetitive occlusions of the umbilical cord (UCO) induced by uterine contractions. Whereas fetal heart rate (FHR) monitoring is widely used clinically, it fails to detect fetal acidemia. Hence, new approaches are needed for early detection of fetal acidemia during labor. We built a mathematical model of the UCO effects on FHR, mean arterial blood pressure (MABP), oxygenation and metabolism. Mimicking fetal experiments, our in silico model reproduces salient features of experimentally observed fetal cardiovascular and metabolic behavior including FHR overshoot, gradual MABP decrease and mixed metabolic and respiratory acidemia during UCO. Combined with statistical analysis, our model provides valuable insight into the labor-like fetal distress and guidance for refining FHR monitoring algorithms to improve detection of fetal acidemia and cardiovascular decompensation. PMID:26582358

  19. Characterization of fluid physics effects on cardiovascular response to microgravity (G-572)

    NASA Technical Reports Server (NTRS)

    Pantalos, George M.; Bennett, Thomas E.; Sharp, M. Keith; Woodruff, Stewart; Oleary, Sean; Gillars, Kevin; Lemon, Mark; Sojka, Jan

    1995-01-01

    The investigation of cardiovascular adaptation to space flight has seen substantial advancement in the last several years. In-flight echocardiographic measurements of astronaut cardiac function on the Space Shuttle have documented an initial increase, followed by a progressive reduction in both left ventricular volume index and stroke volume with a compensatory increase in heart rate to maintain cardiac output. To date, the reduced cardiac size and stroke volume have been presumed to be the consequence of the reduction in circulating fluid volume within a few days after orbital insertion. However, no specific mechanism for the reduced stroke volume has been identified. The following investigation proposes the use of a hydraulic model of the cardiovascular system to examine the possibility that the observed reduction in stroke volume may, in part, be related to fluid physics effects on heart function. The automated model is being prepared to fly as a Get Away Special (GAS) payload within the next year.

  20. Plasma Epinephrine Levels and Cardiovascular Response to High Administered Doses of Epinephrine in Local Anesthesia

    PubMed Central

    Troullos, Emanuel S.; Goldstein, David S.; Hargreaves, Kenneth M.; Dionne, Raymond A.

    1987-01-01

    The effects of administering an epinephrine-containing local anesthetic on plasma catecholamine levels and cardiovascular parameters were evaluated. Significant elevations were observed following administration of 8 dental cartridges of 2% lidocaine with epinephrine 1:100,000 (144 μg) throughout the 20 minute observation period, while minimal changes were observed in the patients who received 6 cartridges of 3% mepivicaine. One minute after injection, the mean plasma epinephrine level in the group receiving epinephrine was 27.5 times higher than baseline. Concurrent elevations in systolic pressure (15%), heart rate (33%), and the rate-pressure product (52%) were also observed. These results indicate that significant amounts of epinephrine can be systemically absorbed following intraoral injection and the absorbed epinephrine can alter the cardiovascular status of the patient. PMID:3472472

  1. Neural Regulation of Cardiovascular Response to Exercise: Role of Central Command and Peripheral Afferents

    PubMed Central

    Nobrega, Antonio C. L.; O'Leary, Donal; Silva, Bruno Moreira; Piepoli, Massimo F.; Crisafulli, Antonio

    2014-01-01

    During dynamic exercise, mechanisms controlling the cardiovascular apparatus operate to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout. Moreover, arterial blood pressure is regulated to maintain adequate perfusion of the vital organs without excessive pressure variations. The autonomic nervous system adjustments are characterized by a parasympathetic withdrawal and a sympathetic activation. In this review, we briefly summarize neural reflexes operating during dynamic exercise. The main focus of the present review will be on the central command, the arterial baroreflex and chemoreflex, and the exercise pressure reflex. The regulation and integration of these reflexes operating during dynamic exercise and their possible role in the pathophysiology of some cardiovascular diseases are also discussed. PMID:24818143

  2. Central moxonidine on salivary gland blood flow and cardiovascular responses to pilocarpine.

    PubMed

    Moreira, Thiago Santos; Takakura, Ana Carolina Thomaz; Colombari, Eduardo; De Luca, Laurival Antonio; Renzi, Antonio; Menani, José Vanderlei

    2003-10-17

    Peripheral treatment with the cholinergic agonist pilocarpine induces intense salivation that is inhibited by central injections of the alpha2-adrenergic/imidazoline receptor agonist moxonidine. Salivary gland blood flow controlled by sympathetic and parasympathetic systems may affect salivation. We investigated the changes in mean arterial pressure (MAP) and in the vascular resistance in the submandibular/sublingual gland (SSG) artery, superior mesenteric (SM) artery and low abdominal aorta (hindlimb) in rats treated with intraperitoneal (i.p.) pilocarpine alone or combined with intracerebroventricular (i.c.v.) moxonidine. Male Holtzman rats with stainless steel cannula implanted into lateral ventricle (LV) and anesthetized with urethane were used. Pilocarpine (4 micromol/kg of body weight) i.p. reduced SSG vascular resistance (-50+/-13% vs. vehicle: 5+/-3%). Pilocarpine i.p. also increased mesenteric vascular resistance (15+/-5% vs. vehicle: 2+/-3%) and MAP (16+/-3 mmHg, vs. vehicle: 2+/-3 mmHg). Moxonidine (20 nmol) i.c.v. increased SSG vascular resistance (88+/-12% vs. vehicle: 7+/-4%). When injected 15 min following i.c.v. moxonidine, pilocarpine i.p. produced no change on SSG vascular resistance. Pilocarpine-induced pressor responses and increase in mesenteric vascular resistance were not modified by i.c.v. moxonidine. The treatments produced no change in heart rate (HR) and hindlimb vascular resistance. The results show that (1) i.p. pilocarpine increases mesenteric vascular resistance and MAP and reduces salivary gland vascular resistance and (2) central moxonidine increases salivary gland vascular resistance and impairs pilocarpine-induced salivary gland vasodilatation. Therefore, the increase in salivary gland vascular resistance may play a role in the anti-salivatory response to central moxonidine. PMID:14499959

  3. Cardiovascular responses of semi-arboreal snakes to chronic, intermittent hypergravity

    NASA Technical Reports Server (NTRS)

    Lillywhite, H. B.; Ballard, R. E.; Hargens, A. R.

    1996-01-01

    Cardiovascular functions were studied in semi-arboreal rat snakes (Elaphe obsoleta) following long-term, intermittent exposure to +1.5 Gz (head-to-tail acceleration) on a centrifuge. Snakes were held in a nearly straight position within horizontal plastic tubes during periods of centrifugation. Centrifugal acceleration, therefore, subjected snakes to a linear force gradient with the maximal force being experienced at the tail. Compared to non-centrifuged controls, Gz-acclimated snakes showed greater increases of heart rate during head-up tilt or acceleration, greater sensitivity of arterial pressure to circulating catecholamines, higher blood levels of corticosterone, and higher blood ratios of prostaglandin F 2 alpha/prostaglandin E2. Cardiovascular tolerance to increased gravity during graded Gz acceleration was measured as the maximum (caudal) acceleration force at which carotid arterial blood flow became null. When such tolerances were adjusted for effects of body size and other continuous variables incorporated into an analysis of covariance, the difference between the adjusted mean values of control and acclimated snakes (2.37 and 2.84 Gz, respectively) corresponded closely to the 0.5 G difference between the acclimation G (1.5) and Earth gravity (1.0). As in other vertebrates, cardiovascular tolerance to Gz stress tended to be increased by acclimation, short body length, high arterial pressure, and comparatively large blood volume. Voluntary body movements were important for promoting carotid blood flow at the higher levels of Gz stress.

  4. Effects of citalopram treatment on behavioural, cardiovascular and neuroendocrine response to cholecystokinin tetrapeptide challenge in patients with panic disorder.

    PubMed Central

    Shlik, J; Aluoja, A; Vasar, V; Vasar, E; Podar, T; Bradwejn, J

    1997-01-01

    Eight patients with panic disorder were administered 20 micrograms of cholecystokinin tetrapeptide (CCK-4) before and after 8 weeks of treatment with the selective serotonin reuptake inhibitor (SSRI) citalopram. All patients responded to treatment by showing a significant general improvement and reaching a panic-free state for 2 weeks. At the rechallenge with CCK-4, patients displayed a marked reduction in the intensity and number of panic symptoms. The frequency of panic attacks induced with CCK-4 decreased by 50% after treatment. Citalopram treatment had no substantial effect on cardiovascular (heart rate and blood pressure) or hormonal (cortisol, prolactin and growth hormone) responses to CCK-4. Patients who still had panic attacks after treatment demonstrated a blunted growth hormone response to CCK-4 that was not seen in those who did not have panic attacks. This study suggests that treatment with an SSRI can reduce an enhanced sensitivity to CCK-4 without modifying cardiovascular and neuroendocrine responses to CCK-4 in patients with panic disorder. PMID:9401314

  5. Renal and cardiovascular responses to water immersion in essential hypertension: is there a role for the opioidergic system?

    PubMed

    Coruzzi, Paolo; Parati, Gianfranco; Brambilla, Lorenzo; Brambilla, Valerio; Gualerzi, Massimo; Novarini, Almerico; Mancia, Giuseppe; Castiglioni, Paolo; Di Rienzo, Marco

    2003-01-01

    Our study aimed at elucidating the effects of acute central hypervolemia induced by water immersion (WI) on renal hemodynamics, hormonal responses and on cardiovascular control in hypertensive patients, as well as at evaluating the possible role of the opioidergic system (OS) in determining these effects. Thirteen essential hypertensives were studied for 2 h before and for 2 h during WI. This was done twice, without and with i.v. injection of the OS antagonist naloxone. Before and during WI alone, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), renal vascular resistance (RVR), mean arterial pressure (MAP), pulse interval (PI), spontaneous baroreflex sensitivity (BRS), Low frequency to High frequency (LF/HF) ratio in PI spectra, hematocrit, urinary sodium excretion, plasma renin activity (PRA) and aldosterone (PA) were assessed. Based on their response to WI, hypertensives were subdivided into two groups: ERPF+ (n = 7) in whom WI increased ERPF, and ERPF- (n = 6) in whom WI reduced ERPF. ERPF+ displayed a higher BRS than ERPF- at baseline and during WI. A suppression of PRA and PA and an increase in MAP and urinary sodium excretion were found in both groups. In ERPF+ naloxone caused RVR and MAP to increase during WI and this response was associated with a blockade of the increase in ERPF in this group, while BRS and natriuresis were unchanged. In ERPF- naloxone did not affect WI-induced MAP, ERPF, RVR and BRS changes, while it blunted sodium excretion. Our data provide the first evidence of a differentiate renal hemodynamic response to WI in hypertension; they also suggest that while OS may significantly potentiate the renal vasodilatory response to WI in ERPF+, it does not affect the natriuretic response nor the changes in systemic cardiovascular regulation induced by central hypervolemia. PMID:12902616

  6. Cardiovascular responses to peripheral chemoreflex activation and comparison of different methods to evaluate baroreflex gain in conscious mice using telemetry.

    PubMed

    Braga, Valdir A; Burmeister, Melissa A; Sharma, Ram V; Davisson, Robin L

    2008-10-01

    Peripheral chemoreceptors located in the carotid bodies are the primary sensors of systemic hypoxia. Although the pattern of responses elicited by peripheral chemoreceptor activation is well established in rats, lambs, and rabbits, the cardiovascular responses to peripheral chemoreflex activation in conscious mice have not been delineated. Here we report that stimulation of peripheral chemoreceptors by potassium cyanide (KCN) in conscious mice elicits a unique biphasic response in blood pressure that is characterized by an initial and robust rise followed by a decrease in blood pressure, which is accompanied by a marked reduction in heart rate. The depressor and bradycardic responses to KCN were abolished by muscarinic receptor blockade with atropine, and the pressor response was abolished by alpha-adrenergic receptor blockade with prazosin, suggesting that vagal and sympathetic drive to the heart and sympathetic drive to the vasculature mediate these cardiovascular responses. These studies characterized the chemoreflex in conscious mice and established the reliability of using them for studying hypoxia-related diseases such as obstructive sleep apnea. In another series of experiments, two methods for analyzing baroreflex sensitivity were compared: the classical pharmacological approach using phenylephrine and sodium nitroprusside (i.e., the Oxford technique) or the sequence method for analyzing spontaneous baroreflex activity. Our findings indicate that both methods are reliable, and the sequence method certainly has its benefits as a predictive tool in the context of long-term noninvasive studies using telemetry. However, for absolute determination of baroreflex function, analysis of spontaneous baroreflex activity should be complemented by the classical pharmacological method. PMID:18667715

  7. Centrally administered CDP-choline induced cardiovascular responses are mediated by activation of the central phospholipase-prostaglandin signaling cascade.

    PubMed

    Topuz, Bora B; Altinbas, Burcin; Ilhan, Tuncay; Yilmaz, Mustafa S; Erdost, Hatice; Saha, Sikha; Savci, Vahide; Yalcin, Murat

    2014-05-14

    The present study was designed to determine the involvement of central prostaglandin synthesis on the pressor and bradycardic effect of cytidine 5'-diphosphocholine (CDP-choline). Intracerebroventricular (i.c.v.) administration of CDP-choline was made and blood pressure and heart rate were recorded in male Sprague Dawley rats throughout this study. Microdialysis and immunohistochemical studies were performed to measure extracellular total prostaglandin concentration and to show cyclooxygenase-1 and -2 (COX-1 and -2) immunoreactivities, respectively, in the posterior hypothalamic area. Moreover, rats were pretreated (i.c.v) with mepacrine [a phospholipase A2 (PLA2) inhibitor], ibuprofen [a nonselective COX inhibitor], neomycine [a phospholipase C (PLC) inhibitor] or furegrelate [a thromboxane A2 (TXA2) synthesis inhibitor] 5 min prior to the injection of CDP-choline to determine the effects of these inhibitors on cardiovascular responses to CDP-choline. Control rats were pretreated (i.c.v) with saline. CDP-choline caused a dose- and time-dependent increase in blood pressure and decrease in heart rate. Immunohistochemical studies showed that CDP-choline increased COX-1 and -2 immunoreactivities in the posterior hypothalamic area. CDP-choline also elevated hypothalamic extracellular total prostaglandin concentration by 62%, as shown in microdialysis studies. Mepacrine or ibuprofen pretreatments almost completely blocked the pressor and bradycardic responses to CDP-choline while neomycine or furegrelate partially attenuated the drug-induced cardiovascular effects. The results suggest that CDP-choline may stimulate prostaglandin synthesis through the activation of PLA2, cyclooxygenases (COX-1 and -2) and prostaglandins and at least TXA2, may mediate the drug׳s cardiovascular effects. PMID:24704528

  8. Testing Whether and When Abstract Symmetric Patterns Produce Affective Responses

    PubMed Central

    Bertamini, Marco; Makin, Alexis; Pecchinenda, Anna

    2013-01-01

    Symmetry has a central role in visual art, it is often linked to beauty, and observers can detect it efficiently in the lab. We studied what kind of fast and automatic responses are generated by visual presentation of symmetrical patterns. Specifically, we tested whether a brief presentation of novel symmetrical patterns engenders positive affect using a priming paradigm. The abstract patterns were used as primes in a pattern-word interference task. To ensure that familiarity was not a factor, no pattern and no word was ever repeated within each experiment. The task was to classify words that were selected to have either positive or negative valence. We tested irregular patterns, patterns containing vertical and horizontal reflectional symmetry, and patterns containing a 90 deg rotation. In a series of 7 experiments we found that the effect of affective congruence was present for both types of regularity but only when observers had to classify the regularity of the pattern after responding to the word. The findings show that processing abstract symmetrical shapes or random pattern can engender positive or negative affect as long as the regularity of the pattern is a feature that observers have to attend to and classify. PMID:23840892

  9. Characterisation of an oxidative response inhibitor produced by Streptococcus pneumoniae.

    PubMed Central

    Perry, F. E.; Elson, C. J.; Mitchell, T. J.; Andrew, P. W.; Catterall, J. R.

    1994-01-01

    BACKGROUND--Pneumonia caused by infection with Streptococcus pneumoniae is still a major clinical problem. Reactive oxygen species contribute to the killing of these bacteria by polymorphonuclear leucocytes (PMNs). Defence mechanisms of Str pneumoniae which counter reactive oxygen species are characterised. METHODS--PMNs were stimulated with phorbol myristate acetate (PMA) in the presence and absence of Str pneumoniae and supernatants from them, and superoxide (O2-) production was measured by the reduction of ferricytochrome c. RESULTS--Streptococcus pneumoniae, but not Klebsiella pneumoniae or Staphylococcus aureus, inhibited PMA stimulated superoxide production by PMNs. Washed PMNs which had been preincubated with Str pneumoniae autolysis phase supernatants also exhibited depressed H2O2 production in response to PMA. The inhibitory activity was not attributable to non-specific cytotoxicity as assessed by release of the cytoplasmic enzyme lactate dehydrogenase, nor did the supernatants inhibit PMA stimulated degranulation of PMNs. Fractionation of the autolysis phase supernatants revealed inhibitory activity in both the fractions greater than and less than 10 kD. Like pneumolysin the inhibitory activity was heat sensitive. However, both a parent and pneumolysin negative mutant Str pneumoniae, and autolysis phase supernatants from them, inhibited PMN superoxide production. Antisera to pneumolysin failed to abrogate the inhibitory effect of intact Str pneumoniae or autolysis phase supernatants from types 1 or 14 Str pneumoniae. CONCLUSIONS--The inhibitory effect of Str pneumoniae on the respiratory burst of PMNs is not shared by two other common lung pathogens. The existence of a novel inhibitor of the PMN respiratory burst, distinct from pneumolysin, has been demonstrated. The inhibitor is specific for the respiratory burst and is active both in the logarithmic phase of growth and during autolysis. PMID:8066562

  10. Effects of Posttraumatic Stress Disorder Status and Covert Hostility on Cardiovascular Responses to Relived Anger in Women with and without PTSD

    PubMed Central

    Vrana, Scott R.; Hughes, Joel W.; Dennis, Michelle F.; Calhoun, Patrick S.; Beckham, Jean C.

    2009-01-01

    Previous literature has found greater heart rate (HR) and blood pressure (BP) responses during relived anger, and a positive association between covert hostility and relived anger, in male veterans with PTSD. This study investigated hostility and cardiovascular responses to a relived anger task in 120 women (70 with PTSD and 50 without PTSD). Women with PTSD reported greater hostile beliefs and covert hostility than non-PTSD controls, reported greater anger and anxiety during the anger recall task, and had higher resting HR. In general, the relationship between PTSD and cardiovascular response was moderated by covert hostility, which was associated with greater baseline diastolic BP and greater HR during relived anger and anger recovery among women with PTSD, but not among non-PTSD controls. Results suggest that the relationship between PTSD and cardiovascular response is moderated by hostility. PMID:19716397

  11. Influence of passive stretch on muscle blood flow, oxygenation and central cardiovascular responses in healthy young males.

    PubMed

    Kruse, Nicholas T; Silette, Christopher R; Scheuermann, Barry W

    2016-05-01

    The aim of this study was to examine the effect of skeletal muscle stretching on peripheral, central, and autonomic cardiovascular responses in humans. Twelve healthy males completed a controlled passive stretch of the plantar flexors for 4 min at three different intensities. Doppler ultrasound velocimetry and imaging techniques assessed mean leg blood flow (MLBF), antegrade blood flow, and retrograde blood flow of the popliteal artery. Near-infrared spectroscopy assessed the concentration of deoxygenated hemoglobin + myoglobin ([HHb]) and the sum of its deoxygenated and oxygenated forms [i.e., blood volume ([Hbtot])]. Heart rate (HR) and mean arterial pressure were measured simultaneously to peripheral hemodynamic responses. During stretch there was an increase (P < 0.05) in antegrade and retrograde blood flow along with [HHb] and [Hbtot] relative to baseline, whereas MLBF was not altered. HR increased (P < 0.01) in a stretch intensity- and time-dependent manner, suggesting a threshold tension must be met that results in a mechanoreflex-mediated increase in HR. After stretch there was an increase (P < 0.05) in [Hbtot] and MLBF in each condition, suggesting that stretch creates a poststretch hyperemic response. Furthermore, retrograde blood flow was decreased (P < 0.05) after stretch in each stretch condition. Mean arterial pressure was decreased (P < 0.05) after moderate-intensity stretching. Collectively, our data provide novel mechanistic evidence on cardiovascular responses to skeletal muscle stretching in humans. Moreover, the reductions in MAP and retrograde blood flow suggest that stretch transiently reduces myogenic vascular tone in a poststretch resting period. PMID:26945077

  12. [Role of rennin-angiotensin system in cholinergic agonist carbachol-induced cardiovascular responses in ovine fetus].

    PubMed

    Geng, Chun-Song; Wan, Zhen; Feng, Ya-Hong; Fan, Yi-Sun

    2012-06-25

    To investigate the mechanisms underlying the cholinergic agonist carbachol-induced cardiovascular responses, changes of renin-angiotensin system were examined in fetal hormonal systems. In the ovine fetal model under stressless condition, the cardiovascular function was recorded. Blood samples were collected before (during baseline period) and after the intravenous administration of carbachol. Simultaneously, the levels of angiotensin I (Ang I), angiotensin II (Ang II) and vasopressin in the fetal plasma were detected by immunoradiological method. Also, blood gas, plasma osmolality and electrolyte concentrations were analyzed in blood samples. Results showed that in chronically prepared ovine fetus, intravenous infusion of carbachol led to a significant decrease of heart rate (P < 0.05), and a transient decrease followed by an increase of blood pressure (P < 0.05) within 30 min. After the intravenous infusion of carbachol, blood concentrations of Ang I and Ang II in near-term ovine fetus were both significantly increased (P < 0.05); however, blood concentration of vasopressin, values of blood gas, electrolytes and plasma osmolality in near-term ovine fetus were not significantly changed (P > 0.05). Blood levels of Ang I and Ang II in the atropine (M receptor antagonist) + carbachol intravenous administration group was lower than those in the carbachol group without atropine administration (P < 0.05). In conclusion, this study indicates that the near-term changes of cardiovascular system induced by intravenous administration of carbachol in ovine fetus, such as blood pressure and heart rate, are associated with the changes of hormones of circulatory renin-angiotensin system. PMID:22717634

  13. Plasma renin and cardiovascular responses to the cold pressor test differ in black and white populations: The SABPA study.

    PubMed

    Gafane, L F; Schutte, R; Van Rooyen, J M; Schutte, A E

    2016-05-01

    Low plasma renin levels and augmented cardiovascular reactivity to stress are common in blacks and have been linked to the development of hypertension in this population. We (i) compared cardiovascular and plasma renin reactivity to a cold pressor test between a black and white population; and (ii) investigated the associations between cardiovascular and plasma renin reactivity within the black and white populations. Our population consisted of 153 black and 188 white men and women (age range, 20-65 years). We measured blood pressure (BP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), Windkessel arterial compliance, and determined plasma renin levels at rest and during the cold pressor test. Reactivity was calculated for each participant as the percentage change from the resting value. We found lower renin and elevated BP in blacks compared with whites at rest and during stress (both, P<0.001). During stress, HR increased more in blacks (P<0.001), whereas SV (P<0.001) and arterial compliance (P=0.013) decreased more in blacks compared with whites. TPR reactivity was positively associated with renin reactivity in blacks only (β=0.17; P=0.041), while in whites diastolic BP reactivity was positively associated with renin reactivity (β=0.21; P=0.005). Although blacks had suppressed renin levels at rest and during acute stress, vascular resistance reactivity associated positively with renin reactivity only in the black population. These results suggest that low renin levels in blacks during rest and stress are linked to increased peripheral vascular responses to stress, which may contribute to elevated BP in blacks. PMID:26310183

  14. Use of systolic pressure variation to predict the cardiovascular response to mini-fluid challenge in anaesthetised dogs.

    PubMed

    Rabozzi, R; Franci, P

    2014-11-01

    Systolic pressure variation (SPV), the maximum variation in systolic pressure values following a single positive pressure breath delivered by controlled mechanical ventilation (CMV), is highly correlated with volaemia in dogs. The aim of this study was to determine an SPV value that would indicate when fluid administration would be beneficial in clinical practice. Twenty-six client-owned dogs were anaesthetised, following which CMV with a peak inspiratory pressure (PIP) of 8 cmH2O was applied. After SPV measurement and recording of heart rate (HR) and blood pressure (BP), 3 mL/kg fluid were administered, then HR and BP were recorded again. Dogs exhibiting a 10% decrease in HR and/or an increase in BP were defined as responders, and their SPV pre-bolus was analysed retrospectively. SPV values > 4 mmHg or >4.5% predicted haemodynamic improvement in dogs with normal cardiovascular function, with a sensitivity of 90% and a specificity of 87%. The area under the curve receiver operating characteristic value for SPV was 0.931 mmHg (95% confidence interval, CI, 0.76-0.99 mmHg) and 0.944% (95% CI 0.78-0.99%). It is proposed that SPV values > 4.5% in dogs with a normal cardiovascular function, anaesthetised with isoflurane in oxygen and air, and on CMV (PIP 8 cmH2O), can be used to predict a cardiovascular response (>10% increase in mean arterial BP and/or >10% decrease in heart rate). PMID:25199508

  15. Postnatal development of the pattern of respiratory and cardiovascular response to systemic hypoxia in the piglet: the roles of adenosine.

    PubMed Central

    Elnazir, B; Marshall, J M; Kumar, P

    1996-01-01

    1. In 3-day-old and 3-week-old spontaneously breathing piglets anaesthetized with Saffan, we have studied ventilatory and cardiovascular responses evoked by 5 min periods of hypoxia (breathing 10 and 6% O2). 2. In 3-day-old piglets both 10 and 6% O2 evoked an increase followed by a secondary fall in ventilation, a gradual tachycardia and a renal vasoconstriction, with an increase in femoral blood flow that was attributable to femoral vasodilatation. Arterial blood pressure rose initially but fell towards control values by the 5th minute of hypoxia. 3. The stable adenosine analogue 2-chloroadenosine (2-CA; 30 mg kg(-1) i.v.) evoked bradycardia and renal vasoconstriction, but had no effect on femoral vasculature. These responses were blocked by the adenosine receptor antagonist 8-phenyltheophylline (8-PT; 8 mg kg(-1) i.v.). 8-PT also abolished the secondary fall in ventilation evoked by 10 and 6% O2 and the renal vasoconstriction evoked by 10% O2, but had no effect on the tachycardia, or on the femoral vascular response. 4. By contrast, in 3-week-old piglets both 10 and 6% O2 evoked a sustained increase in ventilation, tachycardia and a rise in arterial pressure with renal vasoconstriction, but no change in renal blood flow and substantial femoral vasodilatation with an increase in femoral blood flow. 2-CA evoked bradycardia and renal vasoconstriction, as in 3-day-old piglets, but also evoked pronounced femoral vasodilatation. 8-PT blocked these responses and the hypoxia-induced femoral vasodilatation, but had no significant effect on other components of the hypoxia-induced response. 5. We propose that there is postnatal development of the ventilatory and cardiovascular responses evoked by systemic hypoxia and of the role of locally released adenosine in these responses: at 3 days, adenosine released within the central nervous system and within the kidney is a major contributor to the secondary fall in ventilation and renal vasoconstriction respectively, whereas at 3

  16. Extending producer responsibility up and down the supply chain, challenges and limitation.

    PubMed

    Scheijgrond, Jan-Willem

    2011-09-01

    Producers are given increasing responsibility by governmental organizations to address environmental and human rights issues along the supply chain. While producers indeed have a responsibility to address these issues, governments' expectations of producers are often too high and in some cases unrealistic. Ruggie's framework to protect, respect and remedy provides a useful tool to determine the responsibilities of government and business in relation to human rights. If it is applied to product-related environmental aspects, which affect human rights, it offers a good tool to evaluate whether producer responsibility has been implemented in a way to institutionally align business and governments. An analysis of extended producer responsibility up and down the supply chain on the basis of waste electrical and electronic equipment (WEEE) legislation, REACH legislation and conflict minerals shows that such alignment has not been achieved. PMID:21771871

  17. The role of the solitary and paramedian reticular nuclei in mediating cardiovascular reflex responses from carotid baro- and chemoreceptors

    PubMed Central

    Miura, Mitsuhiko; Reis, Donald J.

    1972-01-01

    chemoreceptors; it may serve as an important area integrating cardiovascular activity descending from forebrain, brain stem and cerebellum with baroreceptor reflexes. 8. Cardiovascular reflex responses arising from non-myelinated baroreceptors and all chemoreceptors are mediated by neurones in the intermediate area of the NTS. PMID:5039285

  18. Sex Differences in Platelet Reactivity and Cardiovascular and Psychological Response to Mental Stress in Patients With Stable Ischemic Heart Disease

    PubMed Central

    Samad, Zainab; Boyle, Stephen; Ersboll, Mads; Vora, Amit N.; Zhang, Ye; Becker, Richard C.; Williams, Redford; Kuhn, Cynthia; Ortel, Thomas L.; Rogers, Joseph G.; O’Connor, Christopher; Velazquez, Eric J.; Jiang, Wei

    2016-01-01

    BACKGROUND Although emotional stress is associated with ischemic heart disease (IHD) and related clinical events, sex-specific differences in the psychobiological response to mental stress have not been clearly identified. OBJECTIVES We aimed to study the differential psychological and cardiovascular responses to mental stress between male and female patients with stable IHD. METHODS Patients with stable IHD enrolled in the REMIT (Responses of Mental Stress–Induced Myocardial Ischemia to Escitalopram) study underwent psychometric assessments, transthoracic echocardiography, and platelet aggregation studies at baseline and after 3 mental stress tasks. Mental stress–induced myocardial ischemia (MSIMI) was defined as the development or worsening of regional wall motion abnormality, reduction of left ventricular ejection fraction (LVEF) ≥8% by transthoracic echocardiography, and/or ischemic ST-segment change on electrocardiogram during 1 or more of the 3 mental stress tasks. RESULTS In the 310 participants with known IHD (18% women, 82% men), most baseline characteristics were similar between women and men (including heart rate, blood pressure, and LVEF), although women were more likely to be nonwhite, living alone (p < 0.001), and unmarried (p < 0.001); they also had higher baseline depression and anxiety (p < 0.05). At rest, women had heightened platelet aggregation responses to serotonin (p = 0.007) and epinephrine (p = 0.004) compared with men. Following mental stress, women had more MSIMI (57% vs. 41%, p < 0.04), expressed more negative (p = 0.02) and less positive emotion (p < 0.001), and demonstrated higher collagen-stimulated platelet aggregation responses (p = 0.04) than men. Men were more likely than women to show changes in traditional physiological measures, such as blood pressure (p < 0.05) and double product. CONCLUSIONS In this exploratory analysis, we identified clear, measurable, and differential responses to mental stress in women and men

  19. Community-responsive interventions to reduce cardiovascular risk in American Indians.

    PubMed

    Jobe, Jared B; Adams, Alexandra K; Henderson, Jeffrey A; Karanja, Njeri; Lee, Elisa T; Walters, Karina L

    2012-08-01

    American Indian and Alaska Native (AI/AN) populations bear a heavy burden of cardiovascular disease (CVD), and they have the highest rates of risk factors for CVD, such as cigarette smoking, obesity, and diabetes, of any U.S. population group. Yet, few randomized controlled trials have been launched to test potential preventive interventions in Indian Country. Five randomized controlled trials were initiated recently in AI/AN communities to test the effectiveness of interventions targeting adults and/or children to promote healthy behaviors that are known to impact biological CVD risk factors. This article provides a context for and an overview of these five trials. The high burden of CVD among AI/AN populations will worsen unless behaviors and lifestyles affecting CVD risk can be modified. These five trials, if successful, represent a starting point in addressing these significant health disparities. PMID:22983753

  20. A Proposed Study Examining Individual Differences in Temporal Profiles of Cardiovascular Responses to Head Down Tilt During Fluid Loading

    NASA Technical Reports Server (NTRS)

    Cowings, Patricia; Toscano, William; Winther, Sean; Martinez, Jacqueline; Dominguez, Margaret

    2012-01-01

    Susceptibility of healthy astronauts to orthostatic hypotension and presyncope is exacerbated upon return from spaceflight. The effect of altered gravity during space flight and planetary transition on human cardiovascular function is of critical importance to maintenance of astronaut health and safety. Hypovolemia, reduced plasma volume, is suspected to play an important role in cardiovascular deconditioning following exposure to spaceflight, which may lead to increased peripheral resistance, attenuated arterial baroreflex, and changes in cardiac function. A promising countermeasure for post-flight orthostatic intolerance is fluid loading used to restore lost plasma volume by giving crew salt tablets and water prior to re-entry. The main purpose of the proposed study is to define the temporal profile of cardiac responses to simulated 0-G conditions before and following a fluid loading countermeasure. 8 men and 8 women will be tested during 4 hour exposures at 6o head down tilt (HDT). Each subject will be given two exposures to HDT on separate days, one with and one without fluid loading (one liter of 0.9% saline solution). Stand tests (orthostatic stress) will be done before and after each HDT. Cardiac measures will be obtained with both impedance cardiography and echo ultrasound

  1. Association of heart rate variability and inflammatory response in patients with cardiovascular diseases: current strengths and limitations

    PubMed Central

    Papaioannou, Vasilios; Pneumatikos, Ioannis; Maglaveras, Nikos

    2013-01-01

    Many experimental and clinical studies have confirmed a continuous cross-talk between both sympathetic and parasympathetic branches of autonomic nervous system and inflammatory response, in different clinical scenarios. In cardiovascular diseases, inflammation has been proven to play a pivotal role in disease progression, pathogenesis and resolution. A few clinical studies have assessed the possible inter-relation between neuro-autonomic output, estimated with heart rate variability analysis, which is the variability of R-R in the electrocardiogram, and different inflammatory biomarkers, in patients suffering from stable or unstable coronary artery disease (CAD) and heart failure. Moreover, different indices derived from heart rate signals' processing, have been proven to correlate strongly with severity of heart disease and predict final outcome. In this review article we will summarize major findings from different investigators, evaluating neuro-immunological interactions through heart rate variability analysis, in different groups of cardiovascular patients. We suggest that markers originating from variability analysis of heart rate signals seem to be related to inflammatory biomarkers. However, a lot of open questions remain to be addressed, regarding the existence of a true association between heart rate variability and autonomic nervous system output or its adoption for risk stratification and therapeutic monitoring at the bedside. Finally, potential therapeutic implications will be discussed, leading to autonomic balance restoration in relation with inflammatory control. PMID:23847549

  2. Acute Cardiovascular Response during Resistance Exercise with Whole-body Vibration in Sedentary Subjects: A Randomized Cross-over Trial.

    PubMed

    Dias, Thaisa; Polito, Marcos

    2015-01-01

    This study aimed to compare the acute cardiovascular responses during and after resistance exercise with and without whole-body vibration. Nineteen sedentary adults randomly performed one session of isometric squats without vibration and the same exercise with vibration. Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were measured. SBP, DBP and HR were also measured for 20 min after the sessions. The exercise with vibration demonstrated significant values ​​(P < 0.05) for SBP (second to sixth sets), DBP (third to sixth sets) and SVR (second to sixth sets) compared with the exercise without vibration. After the sessions, the values ​​of SBP for both exercises were significantly lower than the respective resting values; with no difference between the sessions. In conclusion, exercise with vibration caused increases in SBP, DBP and SVR compared with exercise with no vibration in sedentary adults. PMID:26031551

  3. Peculiarities of a Group Response of Cardiovascular System of Volunteers at Different Latitudes to Changes of Space Weather Parameters

    NASA Astrophysics Data System (ADS)

    Parshina, S. S.; Samsonov, S. N.; Manykina, V. I.; Afanasyeva, T. N.; Vishnevsky, V. V.; Petrova, P. G.; Petrova, V. D.; Strekalovskaya, A. A.; Tokayeva, L. K.; Kaplanova, T. I.; Potapova, M. V.

    A simultaneous monitoring in evaluating of the response of a cardiovascular system of healthy volunteers was performed. The research was oriented to changes of a space weather parameters in aurural (Tixie), subauroral (Yakutsk) and medium (Saratov) areas. In each of the experimental groups there was revealed an effect of synchronization between repolarization processes of ventrical myocard responding (according to a T-wave symmetry coefficient of a cardiogram) and geomagnetic activity (according Kp-index). At rest the group effect of synchronization (GES) of myocard in geomagnetic activity change was noticed in 33,3%-61,3% of the respondents. The origin of GES has features depending on the area of habitation and an age of the volunteers. The study is performed with the partial financial support in partnership with Russian-Ukrainian grant RFFI №14-02-90424 ukr_a.

  4. Characterization of fluid physics effects on cardiovascular response to microgravity (G-572)

    NASA Technical Reports Server (NTRS)

    Pantalos, George M.; Sharp, M. Keith; Woodruff, Stewart J.; Lorange, Richard D.; Bennett, Thomas E.; Sojka, Jan J.; Lemon, Mark W.

    1993-01-01

    The recognition and understanding of cardiovascular adaptation to spaceflight has experienced substantial advancement in the last several years. In-flight echocardiographic measurements of astronaut cardiac function on the Space Shuttle have documented a 15 percent reduction in both left ventricular volume index and stroke volume with a compensatory increase in heart rate to maintain cardiac output. To date, the reduced cardiac size and stroke volume have been presumed to be the consequence of the reduction in circulating fluid volume following diuresis and other physiological processes to reduce blood volume within a few days after orbital insertion. However, no specific mechanism for the reduced stroke volume has been elucidated. The following investigation proposes the use of a hydraulic model of the cardiovascular system to examine the possibility that the observed reduction in stroke volume may, in part, be related to fluid physics effects on heart function. The automated model is being prepared to fly as a GAS payload. The experimental apparatus consists of a pneumatically actuated, elliptical artificial ventricle connected to a closed-loop, hydraulic circuit with compliance and resistance elements to create physiologic pressure and flow conditions. The ventricle is instrumented with high-fidelity, acceleration-insensitive, catheter-tip pressure transducers (Millar Instruments) in the apex and base to determine the instantaneous ventricular pressures and (delta)P(sub LV) across the left ventricle (LVP(sub apex)-LVP(sub base). The ventricle is also instrumented with a flow probe and pressure transducers immediately upstream of the inflow valve and downstream of the outflow valve. The experiment will be microprocessor controlled with analog signals stored on the FM data tape recorder. By varying the circulating fluid volume, ventricular function can be determined for varying preload pressures with fixed afterload pressure. Pilot experiments on board the NASA KC

  5. Cardiovascular Safety Assessment in Early-Phase Clinical Studies: A Meta-Analytical Comparison of Exposure-Response Models.

    PubMed

    Conrado, D J; Chen, D; Denney, W S

    2016-06-01

    Exposure-response analysis of QT interval in clinical studies has been proposed as a thorough QT study alternative. Many exposure-response model structures have been proposed for cardiovascular (CV) safety markers, but few studies have compared models across multiple drugs. To recommend preferred drug-effect exposure-response models on vital signs and electrocardiogram (ECG) intervals, an individual-level model-based meta-analysis (39 studies and 1,291 subjects) compared 90 model structures. Models were selected to describe the data and cross-validate studies on the same drug. The most commonly selected baseline model was an unstructured model (estimation of a value at each study nominal time) for all measures but blood pressure. The unstructured model estimated a better cross-validated drug-effect when considering all markers. A linear model was the most commonly selected to characterize drug-effect on all markers. We propose these models as a starting point assisting with CV safety exposure-response assessment in nondedicated small studies with healthy subjects. PMID:27318037

  6. Repeated administration of a mutant cocaine esterase: effects on plasma cocaine levels, cocaine-induced cardiovascular activity, and immune responses in rhesus monkeys.

    PubMed

    Collins, Gregory T; Brim, Remy L; Noon, Kathleen R; Narasimhan, Diwahar; Lukacs, Nicholas W; Sunahara, Roger K; Woods, James H; Ko, Mei-Chuan

    2012-07-01

    Previous studies have demonstrated the capacity of a long-acting mutant form of a naturally occurring bacterial double mutant cocaine esterase (DM CocE) to antagonize the reinforcing, discriminative, convulsant, and lethal effects of cocaine in rodents and reverse the increases in mean arterial pressure (MAP) and heart rate (HR) produced by cocaine in rhesus monkeys. This study was aimed at characterizing the immunologic responses to repeated dosing with DM CocE and determining whether the development of anti-CocE antibodies altered the capacity of DM CocE to reduce plasma cocaine levels and ameliorate the cardiovascular effects of cocaine in rhesus monkeys. Under control conditions, intravenous administration of cocaine (3 mg/kg) resulted in a rapid increase in the plasma concentration of cocaine (n = 2) and long-lasting increases in MAP and HR (n = 3). Administration of DM CocE (0.32 mg/kg i.v.) 10 min after cocaine resulted in a rapid hydrolysis of cocaine with plasma levels below detection limits within 5 to 8 min. Elevations in MAP and HR were significantly reduced within 25 and 50 min of DM CocE administration, respectively. Although slight (10-fold) increases in anti-CocE antibodies were observed after the fourth administration of DM CocE, these antibodies did not alter the capacity of DM CocE to reduce plasma cocaine levels or ameliorate cocaine's cardiovascular effects. Anti-CocE titers were transient and generally dissipated within 8 weeks. Together, these results suggest that highly efficient cocaine esterases, such as DM CocE, may provide a novel and effective therapeutic for the treatment of acute cocaine intoxication in humans. PMID:22518021

  7. Ventilatory, cardiovascular and metabolic responses to hypoxia and hypercapnia in the armadillo.

    PubMed

    Boggs, D F; Frappell, P B; Kilgore, D L

    1998-08-01

    Armadillos have a low resting metabolic rate and high hemoglobin affinity for their size, a rigid carapace and a semi-fossorial life style. These characteristics could contribute to unusual respiratory responses to hypoxia and hypercapnia which were investigated in this study. Ventilatory and oxygen consumption responses of six adult unanesthetized armadillos to 15, 12, 10 and 8% O2 and 1.5, 3, 5 and 7% CO2 were measured by barometric plethysmography and flow-through respirometry. A significant increase in ventilation occurred in response to 10 and 8% O2 but a decline in oxygen consumption only occurred at 8% inspired O2. The convection requirement response has a threshold at a PaO2 of approximately = 28 Torr which corresponds to a Hb saturation of approximately 70%. Ventilation increased in response to 3% and higher levels of CO2, with no change in oxygen consumption. The magnitude of the ventilatory response to CO2 was similar to other semi-fossorial mammals and less than that of nonburrowing species. However, the pattern of the response was unique in being largely a frequency response with little change in tidal volume, contrary to the tidal volume dominated response to hypercapnia typical of mammals. This feature, not shared by another Xenarthran, the sloth, who lacks a carapace, is likely attributable to the low respiratory system compliance and increased airway resistance resulting from the rigid carapace and small lungs of armadillos and emphasizes the importance of respiratory mechanics in determining breathing pattern. PMID:9832229

  8. Effects of vocalization on cardiovascular and electrodermal responses during mental arithmetic.

    PubMed

    Tomaka, J; Blascovich, J; Swart, L

    1994-10-01

    This study assessed the contribution of vocalization to autonomic responses during mental arithmetic. Specifically this study compared the autonomic responses of subjects during aloud and silent phases of repeated mental arithmetic tasks. The results were consistent for both tasks. As expected, heart rate and skin conductance responses were elevated during the aloud phases. Preejection period and cardiac output reactions, however, were greater during the silent phases. Furthermore, stroke volume declined during the aloud phases, but was maintained near resting levels during the silent phases. There were no phase effects for systolic pressure, diastolic pressure, or total peripheral resistance. The pattern of autonomic responses between aloud and silent phases of mental arithmetic suggest that the relationship between vocalization and autonomic response is not unidirectional but varies depending on the physiological parameter under investigation. PMID:7876036

  9. Cardiovascular disease risk factors and blood pressure response during exercise in healthy children and adolescents: the European Youth Heart Study.

    PubMed

    Møller, Niels C; Grøntved, Anders; Wedderkopp, Niels; Ried-Larsen, Mathias; Kristensen, Peter L; Andersen, Lars B; Froberg, Karsten

    2010-10-01

    Raised blood pressure (BP) response during exercise independently predicts future hypertension. Subjects with higher BP in childhood also have elevated BP later in life. Therefore, the factors related to the regulation of exercise BP in children needs to be well understood. We hypothesized that physiological cardiovascular disease (CVD) risk factors would influence BP response during exercise in children and adolescents. This is a cross-sectional study of 439 Danish third-grade children and 364 ninth-grade adolescents. Systolic blood pressure (SBP) was measured with sphygmomanometer during a maximal aerobic fitness test. Examined CVD risk factors were high-density lipoprotein (HDL)- and low-density lipoprotein (LDL)-cholesterol, triglyceride, homeostasis model of assessment of insulin resistance (HOMA-IR) score, body mass index (BMI), waist circumference, and aerobic fitness. A random effect model was used to test the hypotheses. In boys, HOMA-IR score and BMI were positively related to SBP response during exercise (β = 1.03, P = 0.001, and β = 0.58, P = 0.017, respectively). The effects sizes of HOMA-IR score and BMI and the significance levels only changed slightly (β = 0.91, P = 0.004, and β = 0.43, P = 0.08, respectively) when the two variables were added in the same model. A significant positive association was observed between aerobic fitness and SBP response in girls (β = 3.13 and P = 0.002). HOMA-IR score and BMI were found to be positively related to the SBP response in male children and youth. At least partly, adiposity and insulin sensitivity seem to influence exercise SBP through different mechanisms. The positive relationship observed between aerobic fitness and SBP response in girls remains unexplainable for us, although post hoc analyses revealed that it was the case in the ninth graders only. PMID:20634358

  10. Functional evidence of paraventricular nucleus involvement in cardiovascular and autonomic modulation in response to acute microgravity (head-down tilt) in unanesthetized rats.

    PubMed

    Amorim, Eric Diego Turossi; Peras, Vivian Rossi; de Andrade, Ozahyr; Martins-Pinge, Marli Cardoso

    2015-08-01

    Exposure to microgravity induces autonomic and vestibular disorders such as alterations in cardiovascular function. The paraventricular nucleus of the hypothalamus (PVN) is known to be an important center for integrating autonomic and cardiovascular responses as blood volume reflexes. The acute effects promoted by microgravity and PVN involvement in cardiovascular and autonomic parameters have not yet been evaluated. Male Wistar rats were anesthetized to facilitate cannulae implantation in the PVN. After 3 days of surgical recovery, femoral artery and vein catheters were implanted for direct recording of blood pressure and heart rate (HR) in conscious animals to evaluate cardiovascular and autonomic changes in an acute protocol of head-down tilt (HDT) in nonanesthetized rats. During HDT, there was an increase in mean arterial pressure (11 ± 1 mmHg, P < 0.05) and a decrease in HR (-28 ± 5 bpm, P < 0.05). Spectral analysis of systolic arterial pressure showed an increase in the low-frequency (LF) component. In addition, HDT induced a reduction in the LF component and an increase in the high-frequency (HF) component of the pulse interval (PI). PVN inhibition with muscimol reversed bradycardia and blocked the reduction of the LF and HF increases in PI during HDT. These results suggest that the PVN participates in the cardiovascular compensation during HDT, especially modulating cardiac responses. PMID:25821104

  11. Cardiovascular responses to isometric hand grip vs. relaxed hand grip in sustained cycling efforts.

    PubMed

    Canivel, Randy G; Wyatt, Frank B; Baker, Julien S

    2012-11-01

    Peripheral isometric contractions may lead to enhanced performance. Previous research using hand grip protocols indicates increased stabilization and peak power outputs. Research is lacking with the grip vs. no-grip protocol during sustained efforts. The purpose of this study is to determine cardiovascular reactions (i.e., heart rate [HR], blood pressure [BP], and rate pressure product [RPP]) during sustained cycling via an isometric and relaxed hand grip. Nine (n = 9) recreational cyclists participated in this study. After signing a medical and physical readiness questionnaire, the subjects were randomly assigned to 1 of 2 different protocols. Preexercising values of the HR (beats per minute), BP (miilimeters of mercury), height (centimeters), weight (kilograms), and age (years) were assessed before testing. A Monark bicycle ergometer was used for testing. Grip was substantiated through the use of a hand grip dynamometer at 20 kg of tension. Protocol 1 used an isometric "Hand Grip" scenario at 150 W for 20 minutes. Protocol 2 used a "Relaxed Hand Grip" at the same power and time. During the 20-minute exercise test, HR (POLAR), BP (stethoscope and sphygmomanometer), and calculated RPP (HR × systolic BP [SPB]/100) were recorded every minute. Statistical measures included mean and SDs between protocols, and dependent samples t-tests were used to examine differences between grip and no-grip protocols. At an alpha of ≤0.05, SBP did show a significant increase when using no grip, 161.4 (5.1) mm Hg vs. grip, 154.1 (6.6) mm Hg. However, rate pressure product and heart rate showed no significant differences between protocols. Our data suggested that the use of an isometric hand grip is transient and diminishes over time. PMID:22105053

  12. Daytime Napping and the Risk of Cardiovascular Disease and All-Cause Mortality: A Prospective Study and Dose-Response Meta-Analysis

    PubMed Central

    Yamada, Tomohide; Hara, Kazuo; Shojima, Nobuhiro; Yamauchi, Toshimasa; Kadowaki, Takashi

    2015-01-01

    Study Objectives: To summarize evidence about the association between daytime napping and the risk of cardiovascular disease and all-cause mortality, and to quantify the potential dose-response relation. Design: Meta-analysis of prospective cohort studies. Methods and Results: Electronic databases were searched for articles published up to December 2014 using the terms nap, cardiovascular disease, and all-cause mortality. We selected well-adjusted prospective cohort studies reporting risk estimates for cardiovascular disease and all-cause mortality related to napping. Eleven prospective cohort studies were identified with 151,588 participants (1,625,012 person-years) and a mean follow-up period of 11 years (60% women, 5,276 cardiovascular events, and 18,966 all-cause deaths). Pooled analysis showed that a long daytime nap (≥ 60 min/day) was associated with a higher risk of cardiovascular disease (rate ratio [RR]: 1.82 [1.22–2.71], P = 0.003, I2 = 37%) compared with not napping. All-cause mortality was associated with napping for ≥ 60 min/day (RR: 1.27 [1.11–1.45], P < 0.001, I2 = 0%) compared with not napping. In contrast, napping for < 60 min/day was not associated with cardiovascular disease (P = 0.98) or all-cause mortality (P = 0.08). Meta-analysis demonstrated a significant J-curve dose-response relation between nap time and cardiovascular disease (P for nonlinearity = 0.01). The RR initially decreased from 0 to 30 min/day. Then it increased slightly until about 45 min/day, followed by a sharp increase at longer nap times. There was also a positive linear relation between nap time and all-cause mortality (P for non-linearity = 0.97). Conclusions: Nap time and cardiovascular disease may be associated via a J-curve relation. Further studies are needed to confirm the efficacy of a short nap. Citation: Yamada T, Hara K, Shojima N, Yamauchi T, Kadowaki T. Daytime napping and the risk of cardiovascular disease and all-cause mortality: a prospective study and

  13. USE OF RESPIRATORY-CARDIOVASCULAR RESPONSES OF RAINBOW TROUT ('SALMO GAIRDNERI') IN IDENTIFYING ACUTE TOXICITY SYNDROMES IN FISH: PART 2. MALATHION, CARBARYL, ACROLEIN AND BENZALDEHYDE

    EPA Science Inventory

    An in vivo fish model was used to monitor the respiratory-cardiovascular responses of individually spinally transected rainbow trout exposed to acutely toxic aqueous concentrations of two acetylcholinesterase (AChE) inhibitors, malathion and carbaryl, and two mucous membrane irri...

  14. A dose-response of consuming high fructose corn syrup-sweetened beverages on lipid/lipoprotein risk factors for cardiovascular disease in young adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    National Health and Nutrition Examination Survey data show increased risk of cardiovascular disease (CVD) mortality with increased intake of added sugar across quintiles. Objective: To determine the dose response effects of consuming beverages sweetened with high fructose corn syrup (HFCS) at zero, ...

  15. Effects of Sex, Gender Role Identification, and Gender Relevance of Two Types of Stressors on Cardiovascular and Subjective Responses: Sex and Gender Match and Mismatch Effects

    ERIC Educational Resources Information Center

    van Well, Sonja; Kolk, Annemarie M.; Klugkist, Irene G.

    2008-01-01

    The authors tested the hypothesis that a match between the gender relevance of a stressor and one's sex or gender role identification would elicit higher cardiovascular responses. Healthy female and male undergraduates (n = 108) were exposed to two stressors: the Cold Pressor Test (CPT) and the n-back task. Stressor relevance was manipulated to be…

  16. Cardiovascular responses of Type A and Type B behavior patterns to visual stimulation during rest, stress and recovery.

    PubMed

    Lee, Jeong-Mi; Watanuki, Shigeki

    2007-01-01

    Differences in the cardiovascular responses of individuals with behavior patterns of Type A and Type B were investigated during rest, stress, and recovery by visual stimulation. Thirty healthy undergraduate and graduate students (mean age: 22.18+/-1.44 years) were categorized as Type A (N=14), or Type B (N=16) based on the Kwansei Gakuin's daily life questionnaire. The cardiovascular reactivity of all participants was repetitively monitored for 6 sessions, with each session comprising 3 conditional phases, viz., resting, stress, and post-stress recovery. A gray screen was displayed during resting, displeasure-evoking images were displayed under the stress condition, and video clips of a forest or a control image (a gray screen) were displayed during the recovery condition. When participants were subjected to different stimuli on a 42-inch plasma television screen in each session, electrocardiograms (ECG), impedance cardiograms and the blood pressure (BP) of the respective participants were continuously monitored. According to the results, Type A indicated higher sympathetic reactivity than Type B during resting and under stress. As such, Type A indicated a shorter pre-ejection period (PEP) level during resting and a greater cardiac output (CO) increase under stress than Type B. Furthermore, parasympathetic predominance and parasympathetic antagonism accompanying the enhanced sympathetic activity induced by the unpleasant stress images decreased heart rate (HR) in both Type A and Type B, although the decrease in Type A was relatively meager. Unlike previous studies, the present study demonstrated that Type A indicated more enhanced sympathetic reactivity than Type B in resting physiological arousal levels and visual stimulus-induced stress. PMID:17283386

  17. Cardiovascular effects of thyroid disease.

    PubMed

    Sangster, Jodi K; Panciera, David L; Abbott, Jonathan A

    2013-07-01

    Thyroid hormones have many effects on cardiovascular function, and deficiency or excess of thyroid hormones can result in cardiac dysfunction. Abnormalities of the cardiovascular system are often identified during examination of hyperthyroid and hypothyroid patients. This article addresses the effects of thyroid hormones on the cardiovascular system and the clinical relevance of the cardiovascular response to thyroid dysfunction. In addition, treatment recommendations are presented. PMID:23677842

  18. Effort analysis of gender differences in cardiovascular response: Further evidence involving a traditionally feminine incentive.

    PubMed

    Barreto, Patricia; Wright, Rex A; Krubinski, Kimberlee; Molzof, Hylton; Hur, Jinwoo

    2015-07-01

    Participants were presented a moderately- or impossibly difficult cumulative mental addition task with instructions that they could win a traditionally feminine- or masculine incentive if they achieved a 90% success rate. When the incentive was feminine, systolic blood pressure responses during the task period were stronger under moderately difficult conditions among women, but low irrespective of difficulty among men - creating a gender difference only when difficulty was moderate. By contrast, when the incentive was masculine, systolic-, mean arterial- and, to a lesser degree, diastolic blood pressure responses during the task period were stronger under moderately difficult conditions irrespective of gender. The former finding confirmed expectations and adds substantively to the body of evidence favoring a recent effort analysis of gender influence on CV response to performance challenge. The latter findings conflict with what was first expected, but can be understood in terms of post hoc reasoning extended in light of participants' ratings of the masculine incentive. PMID:26032868

  19. Functional topography of respiratory, cardiovascular and pontine-wave responses to glutamate microstimulation of the pedunculopontine tegmentum of the rat

    PubMed Central

    Topchiy, Irina; Waxman, Jonathan; Radulovacki, Miodrag; Carley, David W.

    2010-01-01

    Functionally distinct areas were mapped within the pedunculopontine tegmentum (PPT) of 42 ketamine/xylazine anesthetized rats using local stimulation by glutamate microinjection (10 mM, 5–12 nl). Functional responses were classified as: 1) apnea; 2) tachypnea; 3) hypertension (HTN); 4) sinus tachycardia; 5) genioglossus electromyogram activation or 6) pontine-waves (p-waves) activation. We found that short latency apneas were predominantly elicited by stimulation in the lateral portion of the PPT, in close proximity to cholinergic neurons. Tachypneic responses were elicited from ventral regions of the PPT and HTN predominated in the ventral portion of the antero-medial PPT. We observed sinus tachycardia after stimulation of the most ventral part of the medial PPT at the boundary with nucleus reticularis pontis oralis, whereas p-waves were registered predominantly following stimulation in the dorso-caudal portion of the PPT. Genioglossus EMG activation was evoked from the medial PPT. Our results support the existence of the functionally distinct areas within the PPT affecting respiration, cardio-vascular function, EEG and genioglossus EMG. PMID:20601208

  20. Mind over Matter: Reappraising Arousal Improves Cardiovascular and Cognitive Responses to Stress

    ERIC Educational Resources Information Center

    Jamieson, Jeremy P.; Nock, Matthew K.; Mendes, Wendy Berry

    2012-01-01

    Researchers have theorized that changing the way we think about our bodily responses can improve our physiological and cognitive reactions to stressful events. However, the underlying processes through which mental states improve downstream outcomes are not well understood. To this end, we examined whether reappraising stress-induced arousal could…

  1. Cardiovascular and Affective Responses to Social Stress in Adolescents with Internalizing and Externalizing Problems

    ERIC Educational Resources Information Center

    Hastings, Paul D.; Zahn-Waxler, Carolyn; Usher, Barbara A.

    2007-01-01

    Behavioral responses to stress and challenge are based in emotional and physiological arousal reactions. Adolescents with maladaptive or problematic behavior patterns, such as internalizing or externalizing problems, are likely to show atypical emotional and physiological reactions to stress. Relations between problems and reactions to stress were…

  2. Metabolic and Cardiovascular Responses during Aquatic Exercise in Water at Different Temperatures in Older Adults

    ERIC Educational Resources Information Center

    Bergamin, Marco; Ermolao, Andrea; Matten, Sonia; Sieverdes, John C.; Zaccaria, Marco

    2015-01-01

    Purpose: The aim of this study was to investigate the physiological responses during upper-body aquatic exercises in older adults with different pool temperatures. Method: Eleven older men (aged 65 years and older) underwent 2 identical aquatic exercise sessions that consisted of 3 upper-body exercises using progressive intensities (30, 35, and 40…

  3. Chronic mercury exposure at different concentrations produces opposed vascular responses in rat aorta.

    PubMed

    Azevedo, B F; Simões, M R; Fiorim, J; Botelho, T; Angeli, J K; Vieira, Jva; Alonso, M J; Salaices, M; Dos Santos, L; Vassallo, D V

    2016-07-01

    Mercury chloride exposure for 30 days decreases NO bioavailability and increases oxidative stress. However, the mechanisms underlying the effects of mercury on the cardiovascular system are not completely understood, and it is not known if they are dose-dependent or if some concentrations have no harmful effects. Thus, we investigated the effects of chronic exposure to doses low (half) and high (2.5-fold higher) than that needed to obtain 29 nmol/L of HgCl2 on the vascular function. Three-month-old male Wistar rats received intramuscular (i.m.) HgCl2 for 30 days and were divided in three groups: lower (Low Hg); higher (High Hg); and saline was used as the control. High Hg exposure increased the contractile response to phenylephrine (PHE) in aortic rings, but Low Hg reduced it. The hyporesponsiveness in the Low Hg rats was blunted by endothelial denudation and NOS inhibition with l-NAME (100 μmol/L). The phosphorylated-eNOS/eNOS protein ratio increased in the aortas of Low Hg rats. In the High Hg group, endothelial denudation increased the PHE-induced contractions, while l-NAME had no effects and indomethacin (10 μmol/L), losartan (10 μmol/L) and apocynin (30 μmol/L) reduced this response. In the High Hg group, protein levels of the NADPH oxidase subunit gp91phox and cyclooxygenase-2 increased. Our results support previous suggestions that High Hg increases oxidative stress that might activate an inflammatory cascade and the renin-angiotensin system. However, very low Hg concentrations below the level considered safe still reduced vascular reactivity, suggesting the need for special attention to continuous exposure as a putative cause of increased cardiovascular risk. PMID:27061723

  4. [Cardiovascular responses during laryngeal mask airway insertion in normotensive, hypertensive and chronic renal failure patients].

    PubMed

    Yamauchi, M; Igarashi, M; Tsunoda, K; Edanaga, M; Suzuki, H; Tohdoh, Y; Namiki, A

    1999-08-01

    The hemodynamic response to the insertion of the laryngeal mask airway (LM) following induction with propofol 2 mg.kg-1 was assessed and compared in normotensive (Normal), hypertensive (HT) and chronic renal failure (CRF) patients (n = 23 in each group). Before induction, in HT and CRF groups blood pressure and rate pressure products (RPP) were higher than in Normal group (P < 0.05). Although blood pressure and RPP were decreased in every patient by induction with propofol, no patients needed vasopressor drugs. The decreases of blood pressure and RPP were larger in HT and CRF groups than in Normal group (P < 0.05). There were no differences between groups in heart rate and rate of successful LM insertion. We concluded that LM insertion with propofol 2 mg.kg-1 was an effective induction method preventing the adverse circulatory responses in normotensive, hypertensive and chronic renal failure patients. PMID:10481421

  5. Cardiovascular responses to retigabine in conscious rats – under normotensive and hypertensive conditions

    PubMed Central

    Fretwell, L V; Woolard, J

    2013-01-01

    Background and Purpose Retigabine is a recently approved antiepileptic agent which activates Kv7.2–7.5 potassium channels. It is emerging that these channels have an important role in vascular regulation, but the vascular effects of retigabine in the conscious state are unknown. Hence, in the present study we assessed the regional haemodynamic responses to retigabine in conscious rats. Experimental Approach Male Sprague Dawley rats were chronically instrumented with pulsed Doppler flow probes to measure regional haemodynamic responses to retigabine under control conditions and during acute hypertension induced by infusion of angiotensin II and arginine vasopressin. Further experiments were performed, using the β-adrenoceptor antagonists CGP 20712A, ICI 118551 and propranolol, to elucidate the roles of β-adrenoceptors in the responses to retigabine in vivo and in vitro. Key Results Under normotensive conditions, retigabine induced dose-dependent hypotension and hindquarters vasodilatation, with small, transient renal and mesenteric vasodilatations. In the acutely hypertensive state, the renal and mesenteric, but not hindquarters, vasodilatations were enhanced. The response of the hindquarters vascular bed to retigabine was mediated, in part, by β2-adrenoceptors. However, in vitro experiments confirmed that retigabine did not act as a β-adrenoceptor agonist. Conclusions and Implications We demonstrated that retigabine causes regionally specific vasodilatations, which are different under normotensive and hypertensive conditions, and are, in part, mediated by β2-adrenoceptors in some vascular beds but not in others. These results broadly support previous findings and further indicate that Kv7 channels are a potential therapeutic target for the treatment of vascular diseases associated with inappropriate vasoconstriction. PMID:23581476

  6. Monetary incentive moderates the effect of implicit fear on effort-related cardiovascular response.

    PubMed

    Chatelain, Mathieu; Gendolla, Guido H E

    2016-05-01

    Integrating the implicit-affect-primes-effort model (Gendolla, 2012, 2015) with the principles of motivational intensity theory (Brehm & Self, 1989) we investigated if the effort mobilization deficit observed in people exposed to fear primes (vs. anger primes) in a difficult short-term memory task could be compensated by high monetary incentive. Effort was operationalized as cardiac response. We expected that fear primes should lead to the strongest cardiac pre-ejection period (PEP) reactivity when incentive was high (high subjective demand and high justified effort) and to the weakest response when incentive was low (high subjective demand but only low justified effort). PEP reactivity in the anger-prime conditions should fall in between (high but feasible demand). We obtained the predicted pattern on responses of PEP and systolic blood pressure. The present findings show for the first time that the effort mobilization deficit of participants exposed to fear primes in a difficult cognitive task could be compensated by a high incentive. PMID:27032570

  7. Central and peripheral cardiovascular responses to electrically induced and voluntary leg exercise

    NASA Technical Reports Server (NTRS)

    Saltin, B.; Strange, S.; Bangsbo, J.; Kim, C. K.; Duvoisin, M.; Hargens, A.; Gollnick, P. D.

    1990-01-01

    With long missions in space countermeasures have to be used to secure safe operations in space and a safe return to Earth. Exercises of various forms have been used, but the question has arisen whether electrically induced contractions of muscle especially sensitive to weightlessness and crucial for man's performance would aid in maintaining their optimal function. The physiological responses both to short term and prolonged dynamic exercise performed either voluntarily or induced by electrical stimulation were considered. The local and systemic circulatory responses were similar for the voluntary and electrically induced contractions. The metabolic response was slightly more pronounced with electrical stimulation. This could be a reflection of not only slow twitch (type 1) but also fast twitch (type 2) fibers being recruited when the contractions were induced electrically. Intramuscular pressure recordings indicated that the dominant fraction of the muscle group was engaged regardless of mode of activation. Some 70 percent of the short term peak voluntary exercise capacity could be attained with electrical stimulation. Thus, electrically induced contractions of specific muscle groups should indeed be considered as an efficient countermeasure.

  8. Short-term exercise training improves the cardiovascular response to exercise in the postural orthostatic tachycardia syndrome

    PubMed Central

    Shibata, Shigeki; Fu, Qi; Bivens, Tiffany B; Hastings, Jeffrey L; Wang, Wade; Levine, Benjamin D

    2012-01-01

    Recent studies have suggested the presence of cardiac atrophy as a key component of the pathogenesis of the postural orthostatic tachycardia syndrome (POTS), similar to physical deconditioning. It has also been shown that exercise intolerance is associated with a reduced stroke volume (SV) in POTS, and that the high heart rate (HR) observed at rest and during exercise in these patients is due to this low SV. We tested the hypotheses that (a) circulatory control during exercise is normal in POTS; and (b) that physical ‘reconditioning’ with exercise training improves exercise performance in patients with POTS. Nineteen (18 women) POTS patients completed a 3 month training programme. Cardiovascular responses during maximal exercise testing were assessed in the upright position before and after training. Resting left ventricular diastolic function was evaluated by Doppler echocardiography. Results were compared with those of 10 well-matched healthy sedentary controls. A lower SV resulted in a higher HR in POTS at any given oxygen uptake () during exercise while the cardiac output ()– relationship was normal. was lower in POTS than controls (26.1 ± 1.0 (SEM) vs. 36.3 ± 0.9 ml kg−1 min−1; P < 0.001) due to a lower peak SV (65 ± 3 vs. 80 ± 5 ml; P = 0.009). After training in POTS, HR became lower at any given due to increased SV without changes in the – relationship. increased by 11% (P < 0.001) due to increased peak SV (P = 0.021) and was proportional to total blood volume. Peak HR was similar, but HR recovery from exercise was faster after training than before training (P = 0.036 for training and 0.009 for interaction). Resting diastolic function was mostly normal in POTS before training, though diastolic suction was impaired (P = 0.023). There were no changes in any Doppler index after training. These results suggest that short-term exercise training improves physical fitness and cardiovascular responses during exercise in patients with POTS. PMID

  9. Response-produced timeouts under a progressive-ratio schedule with a punished reset option

    NASA Technical Reports Server (NTRS)

    Dardano, J. F.

    1974-01-01

    An attempt is made to extend the generality of timeouts from positive reinforcement to more complex performances. Pigeons were provided with three continuously available options. Responses on one key resulted in food reinforcement under a progressive-ratio schedule, which requires a larger number of responses for successive reinforcements; responses on a second key, which were shocked, reset the progressive-ratio schedule to its first step; and responses on a third key produced a 3-min timeout. Some of these conditions have been studied previously (Dardano, 1968, 1973; Findley, 1958). Questions of general interest included the frequency and stability of response-produced timeouts, changes in the properties of the progressive-ratio performance resulting from the occurrence of timeouts, and the similarity of the relationships between timeouts and the reinforced behavior to relationships found under simpler conditions of reinforcement.

  10. Analysis of cardiorespiratory phase coupling and cardiovascular autonomic responses during food ingestion.

    PubMed

    Niizeki, Kyuichi; Saitoh, Tadashi

    2016-05-15

    The present study analyzed whether the phase coherency (λ) of respiratory sinus arrhythmia (RSA) is altered by food ingestion in healthy young subjects. After 5min of resting control, 13 healthy volunteers were asked to eat a solid meal with access to water at their own pace, followed by 5min of the postprandial state. The R-R interval (RRI), beat-to-beat blood pressure (BP), and respiratory activity were recorded using electrocardiography, a Finapres device, and inductance plethysmography, respectively. The stroke volume was calculated by the pulse-contour method from continuous BP measurement, and the cardiac output (CO) was obtained by multiplying the stroke volume by the heart rate. From the oscillatory signals of RSA and respiration, λ was computed; additionally, frequency domain indexes of the heart rate variability (HRV) were calculated using a short-time Fourier transform. A steady-state 3-min resting period (R), food ingestion period (FOOD), and the first 2-min and the last 3-min of the post prandial period were analyzed separately. We also compared the responses to gum chewing (GUM) and water intake (WATER) using the same protocol on separate days. A shortening of RRI and increases in BP and CO were observed in FOOD compared to R, suggesting a shift of sympathovagal balance toward sympathetic activation. Similar responses but smaller magnitudes were observed in the GUM condition, whereas only transient shortening of RRI was observed in the WATER condition. The HRV indexes did not show any significant changes in response to GUM and WATER but sympathovagal balance was shifted in favor of sympathetic dominance in FOOD. λ decreased during all of the conditions. There was a significant negative correlation between λ and the indirect measure of sympathovagal balance. These results suggest that ingestion of food induces enhanced cardiac sympathetic activity and that a phase coherence of RSA could provide a sensitive measure for evaluating the cardiac

  11. Ethics in cardiovascular medicine. Task Force IV: Scientific responsibility and integrity in medical research.

    PubMed

    Frommer, P L; Ross, J; Benson, J A; Friedman, W F; Friesinger, G C; Goldstein, S; Huth, E J; Levine, R J; Malone, T E; Quash, J A

    1990-07-01

    Ethical standards are a set of affirmative responsibilities to which the investigator must subscribe; behavior that is incompatible with these responsibilities should be presumed unethical, whether or not it is explicitly proscribed. This Task Force sought to present these standards as principles or guidelines. In undertaking research an investigator must accept that publicly funded or supported research is intended to yield public benefit; personal gain should be only incidental to and not at the expense of the public benefit. The responsibilities of the investigator are summarized as follows: Design of Research To develop a research design that effectively and efficiently addresses the scientific question while minimizing the likelihood of incorrect or misleading results. To protect the rights and welfare of human subjects, assure the humane use of laboratory animals and protect the safety of laboratory workers and the environment. Conduct of Research To ensure that accepted laboratory and research practices are followed and that all data are accurately collected and properly recorded; the investigator must participate in the review of original data. To carry out research in accordance with that approved by the institutional review board and ensure that fully informed consent is obtained, that the welfare of human subjects is protected and that animal welfare and laboratory safety procedures are carried out. To provide effective ongoing supervision of research trainees and technicians. In multidisciplinary collaborative research, to have at least an overview familiarity with the work outside his or her areas of expertise. In fixed protocol, multicenter collaborative research the investigator must be satisfied with the adequacy of the collaborative activities.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2358596

  12. Daily voluntary exercise alters the cardiovascular response to hemorrhage in conscious male rats.

    PubMed

    Ahlgren, Joslyn K; Hayward, Linda F

    2011-02-24

    The present study tested the hypothesis that voluntary wheel-exercised rats would better tolerate severe hemorrhage (HEM) compared to age matched sedentary (SED) controls. Conscious rats housed with (EX, n = 8) or without (SED, n = 8) a running wheel for 6 weeks underwent a 30% total blood volume HEM over 15 min and were euthanized 90 min later and brain tissue was processed for Fos-like immunoreactivity (FLI). Both EX and SED groups displayed typical responses to HEM (initial tachycardia followed by decreased HR and MAP) but at the end of HEM, mean arterial pressure (93 ± 6 vs 58 ± 3 mm Hg) and heart rate (316 ± 17 vs. 247 ± 22 bpm,) were higher in the EX vs. SED animals and 60 min following the end of HEM, HR remained significantly elevated in the EX vs SED animals. The altered HR response to HEM in the EX animals was linked to a significant difference in sympatho-vagal drive identified by heart rate variability analysis and an augmented baroreflex response to hypotension tested in a separate group of animals (n = 4-5/group). In many of the brain regions analyzed, EX rats displayed lower levels of FLI compared to SED rats. Significantly lower levels of FLI in the EX vs SED rats were identified in the middle and caudal external lateral subnucleus of the lateral parabrachial nucleus and the dorsal cap of the hypothalamic paraventricular nucleus. These results suggest that enhanced tolerance to HEM following daily exercise may result from an EX-induced reduction in excitation or exaggerated inhibition in central circuits involved in autonomic control. PMID:21215710

  13. Double-lumen tube intubation using video laryngoscopy causes a milder cardiovascular response compared to classic direct laryngoscopy

    PubMed Central

    Wei, Wei; Tian, Ming

    2016-01-01

    Objective: To determine whether there is a clinically relevant difference between the circulatory responses to double-lumen tube intubation (DLTI) with the GlideScope video laryngoscope versus the Macintosh direct laryngoscope. Methods: Eighty adult patients requiring double-lumen tubes for thoracic surgery were randomly and equally allocated to either a Macintosh direct laryngoscope group (DL group, n = 40) or a Glide Scope video laryngoscope group (GS group, n = 40). DLTI was performed after airway evaluations and induction of anesthesia. Systolic blood pressure (SBP) and heart rate (HR) were recorded before induction (baseline values), immediately before intubation (post-induction values), at intubation and after intubation. Rate-pressure-product (RPP), and the areas under SBP- and HR-time curves were calculated. All data obtained by the two devices were compared. Results: After laryngoscope insertion, SBP of DL and GS groups changed significantly differently (13.1% vs. 4.6%, P< 0.001), while HR changed similarly (17.2% vs. 14.6%, P = 0.074). One minute after intubation, both SBP and HR significantly increased in both groups (SBP: 11.6% vs. 11.9%; HR: 18.4% vs. 10.8%), but there were no significant differences between the two groups. RPP significantly increased in both groups after laryngoscope insertion (32.6%, P=0.001; 18.2%, P=0.002), and there was a significant difference between the two groups (P =0.001). Throughout intubation, the areas under SBP-time curves had a significant difference between the two groups (P = 0.042), while those under HR-time curves did not differ significantly (P=0.06). Conclusion: The intubation response was most significant upon laryngoscope insertion during the whole intubation process. The GlideScope video laryngoscope induced milder circulatory fluctuations than the Macintosh direct laryngoscope did, suggesting that DLTI using video laryngoscopy can help reduce the cardiovascular response to intubation. PMID:27022341

  14. The role of autacoids and the autonomic nervous system in cardiovascular responses to radio-frequency energy heating.

    PubMed

    Jauchem, J R

    2006-04-01

    Among the potential effects of exposure to high levels of radio-frequency energy (RFE) (which includes microwaves), an increase in body temperature is the primary consequence. Release of autacoids and activity of the autonomic nervous system may influence (or be directly responsible for) some of the physiological changes that occur in conjunction with this hyperthermia. The main focus of this review is the interaction of autacoids and the autonomic nervous system with cardiovascular changes during heating. Differences between environmental and RFE-induced heating (such as rate of temperature change and degree of skin vs. core heating) may be important when considering these effects. Antihistamines exhibited no beneficial effect on circulatory collapse during RFE-induced heating. The serotonergic blocker methysergide decreased survival time in rats during terminal RFE exposure, despite no effects on heart rate (HR) or blood pressure. Although blockade of platelet-activating factor resulted in lower HR before RFE exposure, there was a lack of effect on the subsequent increase in HR during heating. Nitric oxide did not contribute to the hypotension that occurs due to rapid heating by RFE exposure. There have been either no or very limited studies of effects of prostaglandins, bradykinin, or angiotensin on RFE-induced heating responses. beta-Adrenoceptor antagonism with propranolol resulted in significantly decreased survival times and lower final colonic temperatures during RFE exposure. A lack of effects of nadolol on survival time and temperature, coupled with its poor ability to traverse the blood-brain barrier, suggests that central beta-adrenergic stimulation rather than peripheral stimulation may alter thermoregulation. Effects of the autonomic nervous system (as studied by adrenoceptor blockade) on potassium changes during heating have not been fully investigated. Such changes could be important in animals' responses to RFE and other modalities of heating, and

  15. Renal and cardiovascular effects of caffeine: a dose-response study.

    PubMed

    Passmore, A P; Kondowe, G B; Johnston, G D

    1987-06-01

    The effects of increasing oral doses of caffeine (45, 90, 180 and 360 mg) on effective renal plasma flow (ERPF), plasma renin activity (PRA), serum electrolytes, plasma noradrenaline, blood pressure and heart rate were studied in eight healthy male volunteers. Urine volume was increased by 360 mg of caffeine only. At caffeine doses greater than 90 mg urinary sodium excretion was significantly increased. There were no changes in ERPF. Serum potassium was significantly reduced by 360 mg of caffeine. Caffeine increased systolic pressure in a dose related manner. Diastolic pressure was also increased, but not in relation to dose. A 360 mg dose of caffeine produced a late increase in heart rate. These changes were not associated with any alterations in PRA or in plasma noradrenaline. PMID:3297472

  16. Thermoregulatory, cardiovascular, and metabolic responses to mild caloric restriction in the Brown Norway rat

    PubMed Central

    Aydin, Cenk; Gordon, Christopher J

    2013-01-01

    Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known about the regulation of CR-induced hypothermia as a function of the circadian cycle. We assessed how mild CR that resulted in a 10% reduction in body weight affected the 24 h patterns of Tc as well as heart rate (HR) and motor activity (MA) of the Brown Norway rat. Telemetered rats were allowed to feed for 20 weeks ad libitum (AL) or given a CR diet. Tc, HR, and MA of CR rats exhibited nocturnal reductions and diurnal elevations, opposite to that of AL rats. The effects of CR appeared to peak at ∼4 weeks. Metabolic rate (MR) and respiratory exchange ratio (RER) were measured overnight after 18 weeks of CR. MR and RER were elevated markedly at the time of feeding in CR rats and then declined during the night. We found that the pattern of Tc was altered with CR, characterized by elimination of high nocturnal Tc's typically observed in AL animals. In terms of mechanisms to prolong life span in CR animals, we suggest that the shift in the pattern of Tc during CR (i.e., elimination of high Tc's) may be as critical as the overall mean reduction in Tc. Future studies should address how the time of feeding may affect the thermoregulatory response in calorically restricted rats. PMID:24303105

  17. Thermoregulatory, cardiovascular, and metabolic responses to mild caloric restriction in the Brown Norway rat.

    PubMed

    Aydin, Cenk; Gordon, Christopher J

    2013-07-01

    Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known about the regulation of CR-induced hypothermia as a function of the circadian cycle. We assessed how mild CR that resulted in a 10% reduction in body weight affected the 24 h patterns of Tc as well as heart rate (HR) and motor activity (MA) of the Brown Norway rat. Telemetered rats were allowed to feed for 20 weeks ad libitum (AL) or given a CR diet. Tc, HR, and MA of CR rats exhibited nocturnal reductions and diurnal elevations, opposite to that of AL rats. The effects of CR appeared to peak at ∼4 weeks. Metabolic rate (MR) and respiratory exchange ratio (RER) were measured overnight after 18 weeks of CR. MR and RER were elevated markedly at the time of feeding in CR rats and then declined during the night. We found that the pattern of Tc was altered with CR, characterized by elimination of high nocturnal Tc's typically observed in AL animals. In terms of mechanisms to prolong life span in CR animals, we suggest that the shift in the pattern of Tc during CR (i.e., elimination of high Tc's) may be as critical as the overall mean reduction in Tc. Future studies should address how the time of feeding may affect the thermoregulatory response in calorically restricted rats. PMID:24303105

  18. Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion.

    PubMed

    Florian, John P; Simmons, Erin E; Chon, Ki H; Faes, Luca; Shykoff, Barbara E

    2013-11-01

    The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32-33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variability (HRV) frequency-domain variables [low-frequency (LF), high-frequency (HF), and normalized (n)] were measured. Cold pressor test showed lower HR, SBP, SV, Q, calf BF, LFnHRV, and LF/HFHRV and higher CVR and HFnHRV after than before WI (P < 0.05). Handgrip test showed no effect of WI on maximum strength and endurance and lower HR, SBP, SV, Q, and calf BF and higher SVR and CVR after than before WI (P < 0.05). During postexercise muscle ischemia, HFnHRV increased from baseline after WI only, and LFnHRV was lower after than before WI (P < 0.05). HUT test showed lower SBP, DBP, SV, forearm BF, and BRS and higher HR, FVR, LF/HFHRV, and LFnHRV after than before WI (P < 0.05). The changes suggest differential activation/depression during cold pressor and handgrip (reduced sympathetic/elevated parasympathetic) and HUT (elevated sympathetic/reduced parasympathetic) following 6 h of WI. PMID:23950166

  19. Seaweed supplements normalise metabolic, cardiovascular and liver responses in high-carbohydrate, high-fat fed rats.

    PubMed

    Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C; Paul, Nicholas A; Brown, Lindsay

    2015-02-01

    Increased seaweed consumption may be linked to the lower incidence of metabolic syndrome in eastern Asia. This study investigated the responses to two tropical green seaweeds, Ulva ohnoi (UO) and Derbesia tenuissima (DT), in a rat model of human metabolic syndrome. Male Wistar rats (330-340 g) were fed either a corn starch-rich diet or a high-carbohydrate, high-fat diet with 25% fructose in drinking water, for 16 weeks. High-carbohydrate, high-fat diet-fed rats showed the signs of metabolic syndrome leading to abdominal obesity, cardiovascular remodelling and non-alcoholic fatty liver disease. Food was supplemented with 5% dried UO or DT for the final 8 weeks only. UO lowered total final body fat mass by 24%, systolic blood pressure by 29 mmHg, and improved glucose utilisation and insulin sensitivity. In contrast, DT did not change total body fat mass but decreased plasma triglycerides by 38% and total cholesterol by 17%. UO contained 18.1% soluble fibre as part of 40.9% total fibre, and increased magnesium, while DT contained 23.4% total fibre, essentially as insoluble fibre. UO was more effective in reducing metabolic syndrome than DT, possibly due to the increased intake of soluble fibre and magnesium. PMID:25648511

  20. Seaweed Supplements Normalise Metabolic, Cardiovascular and Liver Responses in High-Carbohydrate, High-Fat Fed Rats

    PubMed Central

    Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C.; Paul, Nicholas A.; Brown, Lindsay

    2015-01-01

    Increased seaweed consumption may be linked to the lower incidence of metabolic syndrome in eastern Asia. This study investigated the responses to two tropical green seaweeds, Ulva ohnoi (UO) and Derbesia tenuissima (DT), in a rat model of human metabolic syndrome. Male Wistar rats (330–340 g) were fed either a corn starch-rich diet or a high-carbohydrate, high-fat diet with 25% fructose in drinking water, for 16 weeks. High-carbohydrate, high-fat diet-fed rats showed the signs of metabolic syndrome leading to abdominal obesity, cardiovascular remodelling and non-alcoholic fatty liver disease. Food was supplemented with 5% dried UO or DT for the final 8 weeks only. UO lowered total final body fat mass by 24%, systolic blood pressure by 29 mmHg, and improved glucose utilisation and insulin sensitivity. In contrast, DT did not change total body fat mass but decreased plasma triglycerides by 38% and total cholesterol by 17%. UO contained 18.1% soluble fibre as part of 40.9% total fibre, and increased magnesium, while DT contained 23.4% total fibre, essentially as insoluble fibre. UO was more effective in reducing metabolic syndrome than DT, possibly due to the increased intake of soluble fibre and magnesium. PMID:25648511

  1. Attenuated cardiovascular hypertrophy and oxidant generation in response to angiotensin II infusion in glutaredoxin-1 knockout mice

    PubMed Central

    Bachschmid, Markus M.; Xu, Shanqin; Maitland-Toolan, Karlene A.; Ho, Ye-Shih; Cohen, Richard A.; Matsui, Reiko

    2010-01-01

    Glutaredoxin-1 (Glrx) is a thioltransferase that regulates protein S-glutathiolation. To elucidate the role of endogenous Glrx in cardiovascular disease, Glrx knockout (KO) mice were infused with angiotensin II (Ang II) for 6 days. After Ang II infusion, body weight and blood pressure were similar between WT and Glrx KO mice. However, compared to WT mice, Glrx KO mice demonstrated (1) less cardiac and aortic medial hypertrophy, (2) less oxidant generation in aorta assessed by dihydroethidium staining and nitrotyrosine, (3) decreased phosphorylation of Akt in the heart, and (4) less expression of inducible NOS (iNOS) in aorta and heart. In cultured embryonic fibroblasts from Glrx KO mice, S-glutathiolation of actin was enhanced and actin depolymerization was impaired after hydrogen peroxide stimulation compared with WT cells. Furthermore, oxidant generation in phorbol ester-stimulated fibroblasts and RAW 264.7 macrophage-like cells was lower with Glrx siRNA knockdown. These data indicate that Ang II-induced oxidant production and hypertrophic responses were attenuated in Glrx KO mice, which may result from impaired NADPH oxidase activation. PMID:20638471

  2. Cardiovascular and behavioral responses of gray wolves to ketamine-xylazine immobilization and antagonism by yohimbine

    USGS Publications Warehouse

    Kreeger, T.J.; Faggella, A.M.; Seal, U.S.; Mech, L.D.; Callahan, M.; Hall, B.

    1987-01-01

    Adult wolves (Canis lupus) were immobilized with 6.6 mg/kg ketamine hydrochloride (KET) and 2.2 mg/kg xylazine hydrochloride (XYL) administered intramuscularly. Induction time was 4.6 +/- 0.3 min (mean +/- SE). Immobilization resulted in significant bradycardia and hypertension (P less than 0.05). Twenty min after induction, the wolves were given 0.05-0.60 mg/kg yohimbine hydrochloride (YOH). Yohimbine given intravenously produced dose-related increases in heart rate (HR) with doses greater than 0.15 mg/kg resulting in extreme tachycardia (greater than 300 bpm). All doses of YOH caused a temporary decrease in mean arterial blood pressure (MABP) with some individual animals manifesting profound hypotension (less than 30 torr) at doses greater than 0.15 mg/kg. Increasing the dose of YOH above 0.15 mg/kg did not significantly decrease either arousal or ambulation times. Administering YOH at 40 or 60 min after induction resulted in decreased arousal and ambulation times. Stimulation by weighing and taking repeated blood samples during anesthesia did not shorten arousal times. We recommend that wolves immobilized with XYL-KET be antagonized with doses of YOH less than 0.15 mg/kg.

  3. Polymorphisms in LEP and NPY genes modify the response to soluble fibre Plantago ovata husk intake on cardiovascular risk biomarkers.

    PubMed

    Crescenti, Anna; Solà, Rosa; Valls, Rosa M; Anguera, Anna; Arola, Lluís

    2013-01-01

    The satiating effect of fibre consumption has been related to gut hormones, such as peptide YY and leptin. These peptides may also influence cardiovascular (CVD) risk biomarkers. Nevertheless, there is wide interindividual variation in metabolic responses to fibre consumption. The objective was to investigate differences in the effects of soluble fibre, in the form of Plantago ovata husk (Po-husk) treatment, on CVD risk biomarkers according to selected polymorphisms in genes related to satiety. The study was a multi-centred, double-blind, placebo-controlled, parallel and randomised trial in mild-moderate hypercholesterolaemic patients (age range: 43-67 years). Eight polymorphisms in three genes related to satiety (LEP, NPY and PYY) were identified in 178 participants; 88 patients in the placebo (microcrystalline cellulose 14 g/day) group and 90 in the Po-husk (14 g/day) group, which had added to a low-saturated-fat diet for 8 weeks. The CVD biomarkers measured included the following: lipid profile, blood pressure (BP), glucose, insulin, hs-CRP, oxidised LDL and IL-6. Relative to the placebo, Po-husk consumption lowered the plasma total cholesterol concentration by 3.3 % according to rs7799039 polymorphism in the LEP gene (p < 0.05). Furthermore, the Po-husk reduced systolic BP (mean [95 % CI]) by -8 mmHg (-14.16; -1.90) and hs-CRP by 24.9 % in subjects with the AA genotype of the rs16147 polymorphism in the NPY gene (32 % of our total population; p < 0.05), which remained significant after Bonferroni correction. In conclusion, polymorphisms in the LEP and NPY genes potentiate the response to Po-husk, particularly the effects on systolic BP and the hs-CRP plasma concentration. PMID:22669627

  4. Age Differences in Affective and Cardiovascular Responses to a Negative Social Interaction: The Role of Goals, Appraisals, and Emotion Regulation

    PubMed Central

    Luong, Gloria; Charles, Susan T.

    2014-01-01

    Older adults often report less affective reactivity to interpersonal tensions than younger individuals, but few studies have directly investigated mechanisms explaining this effect. The current study examined whether older adults’ differential endorsement of goals, appraisals, and emotion regulation strategies (i.e., conflict avoidance/de-escalation, self-distraction) during a controlled negative social interaction may explain age differences in affective and cardiovascular responses to the conflict discussion. Participants (N=159; 80 younger adults, 79 older adults) discussed hypothetical dilemmas with disagreeable confederates. Throughout the laboratory session, participants’ subjective emotional experience, blood pressure, and pulse rate were assessed. Older adults generally exhibited less reactivity (negative affect reactivity, diastolic blood pressure reactivity, and pulse rate reactivity) to the task, and more pronounced positive and negative affect recovery following the task, than did younger adults. Older adults appraised the task as more enjoyable and the confederate as more likeable, and more strongly endorsed goals to perform well on the task, which mediated age differences in negative affect reactivity, pulse rate reactivity, and positive affect recovery (i.e., increases in post-task positive affect), respectively. In addition, younger adults showed increased negative affect reactivity with greater use of self-distraction, whereas older adults did not. Together, findings suggest that older adults respond less negatively to unpleasant social interactions than younger adults, and these responses are explained in part by older adults’ pursuit of different motivational goals, less threatening appraisals of the social interaction, and more effective use of self-distraction, compared to younger adults. PMID:24773101

  5. Cardiovascular and autonomic responses after exercise sessions with different intensities and durations

    PubMed Central

    Casonatto, Juliano; Tinucci, Taís; Dourado, Antônio Carlos; Polito, Marcos

    2011-01-01

    BACKGROUND: Several studies have reported the phenomenon of post-exercise hypotension. However, the factors that cause this drop in blood pressure after a single exercise session are still unknown. OBJECTIVE: To investigate the effects of aerobic exercise on the acute blood pressure response and to investigate the indicators of autonomic activity after exercise. METHODS: Ten male subjects (aged 25 ± 1 years) underwent four experimental exercise sessions and a control session on a cycle ergometer. The blood pressure and heart rate variability of each subject were measured at rest and at 60 min after the end of the sessions. RESULTS: Post-exercise hypotension was not observed in any experimental sessions (P > 0.05). The index of parasympathetic neural activity, the RMSSD, only remained lower than that during the pre-exercise session after the high-intensity session (Δ  = -19 ± 3.7 for 15-20 min post-exercise). In addition, this value varied significantly (P < 0.05) between the high- and low-intensity sessions (Δ  =  -30.7 ± 4.0 for the high intensity session, and Δ  =  -9.9 ± 2.5 for the low intensity session). CONCLUSION: The present study did not find a reduction in blood pressure after exercise in normotensive, physically active young adults. However, the measurements of the indicators of autonomic neural activity revealed that in exercise of greater intensity the parasympathetic recovery tends to be slower and that sympathetic withdrawal can apparently compensate for this delay in recovery. PMID:21552672

  6. Effect of Pregabalin on Cardiovascular Responses to Exercise and Postexercise Pain and Fatigue in Fibromyalgia: A Randomized, Double-Blind, Crossover Pilot Study

    PubMed Central

    White, Andrea T.; Light, Kathleen C.; Bateman, Lucinda; Hughen, Ronald W.; Vanhaitsma, Timothy A.; Light, Alan R.

    2015-01-01

    Pregabalin, an approved treatment for fibromyalgia (FM), has been shown to decrease sympathetic nervous system (SNS) activity and inhibit sympathetically maintained pain, but its effects on exercise responses have not been reported. Methods. Using a randomized double-blind crossover design, we assessed the effect of 5 weeks of pregabalin (versus placebo) on acute cardiovascular and subjective responses to moderate exercise in 19 FM patients. Blood pressure (BP), heart rate (HR), and ratings of perceived exertion (RPE) during exercise and ratings of pain, physical fatigue, and mental fatigue before, during, and for 48 hours after exercise were compared in patients on pregabalin versus placebo and also versus 18 healthy controls. Results. On placebo, exercise RPE and BP were significantly higher in FM patients than controls (p < 0.04). Pregabalin responders (n = 12, defined by patient satisfaction and symptom changes) had significantly lower exercise BP, HR, and RPE on pregabalin versus placebo (p < 0.03) and no longer differed from controls (p > 0.26). Cardiovascular responses of nonresponders (n = 7) were not altered by pregabalin. In responders, pregabalin improved ratings of fatigue and pain (p < 0.04), but negative effects on pain and fatigue were seen in nonresponders. Conclusions. These preliminary findings suggest that pregabalin may normalize cardiovascular and subjective responses to exercise in many FM patients. PMID:27026828

  7. Rat Models of Cardiovascular Disease Demonstrate Distinctive Pulmonary Gene Expressions for Vascular Response Genes: Impact of Ozone Exposure

    EPA Science Inventory

    Comparative gene expression profiling of multiple tissues from rat strains with genetic predisposition to diverse cardiovascular diseases (CVD) can help decode the transcriptional program that governs organ-specific functions. We examined expressions of CVD genes in the lungs of ...

  8. DIFFERENCES IN CARDIOVASCULAR RESPONSE TO PM EXPOSURE BETWEEN SPONTANEOUSLY HYPERTENSIVE STROKE-PRONE (SHSP) AND WISTAR-KYOTO (WKY) RATS.

    EPA Science Inventory

    ABSTRACT BODY: Epidemiological studies have shown that cardiovascular morbidity and mortality are associated with exposure to elevated levels of ambient particulate matter (PM), notably in people with pre-existing cardiopulmonary disease. To better understand the mechanisms of PM...

  9. Cardiovascular Deconditioning

    NASA Technical Reports Server (NTRS)

    Charles, John B.; Fritsch-Yelle, Janice M.; Whitson, Peggy A.; Wood, Margie L.; Brown, Troy E.; Fortner, G. William

    1999-01-01

    Spaceflight causes adaptive changes in cardiovascular function that may deleteriously affect crew health and safety. Over the last three decades, symptoms of cardiovascular changes have ranged from postflight orthostatic tachycardia and decreased exercise capacity to serious cardiac rhythm disturbances during extravehicular activities (EVA). The most documented symptom of cardiovascular dysfunction, postflight orthostatic intolerance, has affected a significant percentage of U.S. Space Shuttle astronauts. Problems of cardiovascular dysfunction associated with spaceflight are a concern to NASA. This has been particularly true during Shuttle flights where the primary concern is the crew's physical health, including the pilot's ability to land the Orbiter, and the crew's ability to quickly egress and move to safety should a dangerous condition arise. The study of astronauts during Shuttle activities is inherently more difficult than most human research. Consequently, sample sizes have been small and results have lacked consistency. Before the Extended Duration Orbiter Medical Project (EDOMP), there was a lack of normative data on changes in cardiovascular parameters during and after spaceflight. The EDOMP for the first time allowed studies on a large enough number of subjects to overcome some of these problems. There were three primary goals of the Cardiovascular EDOMP studies. The first was to establish, through descriptive studies, a normative data base of cardiovascular changes attributable to spaceflight. The second goal was to determine mechanisms of cardiovascular changes resulting from spaceflight (particularly orthostatic hypotension and cardiac rhythm disturbances). The third was to evaluate possible countermeasures. The Cardiovascular EDOMP studies involved parallel descriptive, mechanistic, and countermeasure evaluations.

  10. Preventing and Producing Violence: A Critical Analysis of Responses to School Violence.

    ERIC Educational Resources Information Center

    Noguera, Pedro A.

    1995-01-01

    Disciplinary measures based on social control produce prison-like schools that remain unsafe. Coercive strategies disrupt learning and foster an environment of mistrust and resistance. Humanizing the environment and encouraging responsibility and a sense of community are possible solutions. (SK)

  11. Flood-Producing Rainfall and Storm Event Hydrologic Response in Urban Watersheds near Baltimore, MD

    NASA Astrophysics Data System (ADS)

    Smith, B. K.; Smith, J. A.; Baeck, M. L.; Villarini, G.

    2012-12-01

    Previous work has shown a spectrum of storm event hydrologic response across watersheds in the Baltimore, MD metropolitan area. Differences in storm event hydrologic response between urban basins cannot be explained by impervious surface or land use alone. We further explore these differences through a closer look at flood-producing rainfall properties and through numerical experimentation using a watershed model. Rainfall analyses utilize a high resolution radar rainfall dataset (1-km and 15-min resolution, processed through Hydro-NEXRAD and bias corrected) for a ten-year period from 2000-2009. Spatial heterogeneities in flood-producing rainfall suggest that some urban basins may be more prone to flooding due to higher rainfall intensities over the basin. For example, Moores Run, the flashiest basin in the contiguous United States, is located near a rainfall maximum to the northeast of Baltimore. Spatial patterns of flood-producing rainfall vary between urban and non-urban basins. We examine contrasts in storm structure and evolution for storms producing flood in urban and non-urban watersheds. Storm event hydrologic response is examined through analyses using a watershed model of the Dead Run basin based on the Gridded Surface/ Subsurface Hydrologic Analysis (GSSHA) model. The model is used to explore the sensitivity of urban storm event hydrologic response to properties of urban soils, surface and storm drain network structure, and detention basin storage.

  12. Response-Based Strengthening in Task Shifting: Evidence from Shift Effects Produced by Errors

    ERIC Educational Resources Information Center

    Steinhauser, Marco; Hubner, Ronald

    2006-01-01

    The hypothesis is introduced that 1 source of shift costs is the strengthening of task-related associations occurring whenever an overt response is produced. The authors tested this account by examining shift effects following errors and error compensation processes. The authors predicted that following a specific type of error, called task…

  13. Response of summerform pear psylla (Hemiptera: Psyllidae) to male- and female-produced odors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the role of chemical signals in sex attraction of pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), assessing response of summerform male and female psyllids to both male- and female-produced volatile chemicals. Male psyllids were attracted to odors from live females an...

  14. Growth kinetics response of a Salmonella typhimurium poultry marker strain to fresh produce extracts.

    PubMed

    Nutt, J D; Li, X; Woodward, C L; Zabala-Díaz, I B; Ricke, S C

    2003-09-01

    The purpose of this research was to assess growth response of a Salmonella typhimurium poultry marker strain to fresh homogenized vegetables. Salmonella growth rates were significantly higher (p<0.05) in jalapeno extracts than any other produce extract examined. Growth rates on samples of broccoli and lettuce extracts were greater (p<0.05) than the respective growth rates on bell pepper and tomato. Broccoli extracts yielded the highest extent of growth (4 h optical density) followed by jalapeno and bell pepper extracts. From this study, it appears that fresh produce extracts have different abilities to significantly alter growth response in Salmonella. This could potentially be explained by the variations of pH, nutrient availability to the bacteria, or unknown components found within fresh produce. PMID:12798123

  15. Comparison of cardiovascular response to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone in patients with chronic ischemic heart disease

    SciTech Connect

    Hung, J.; McKillip, J.; Savin, W.; Magder, S.; Kraus, R.; Houston, N.; Goris, M.; Haskell, W.; DeBusk, R.

    1982-06-01

    The cardiovascular responses to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone were evaluated by upright bicycle ergometry during equilibrium-gated blood pool scintigraphy in 24 men, mean age 59 +/- 8 years, with chronic ischemic heart disease. Combined static-dynamic effort and the postprandial state elicited a peak cardiovascular response similar to that of dynamic effort alone. Heart rate, intraarterial systolic and diastolic pressures, rate-pressure product and ejection fraction were similar for the three test conditions at the onset of ischemia and at peak effort. The prevalence and extent of exercise-induced ischemic left ventricular dysfunction, ST-segment depression, angina pectoris and ventricular ectopic activity were also similar during the three test conditions. Direct and indirect measurements of systolic and diastolic blood pressure were highly correlated. The onset of ischemic ST-segment depression and angina pectoris correlated as strongly with heart rate alone as with the rate-pressure product during all three test conditions. The cardiovascular response to combined static-dynamic effort and to postprandial dynamic effort becomes more similar to that of dynamic effort alone as dynamic effort reaches a symptom limit. If significant ischemic and arrhythmic abnormalities are absent during symptom-limited dynamic exercise testing, they are unlikely to appear during combined static-dynamic or postprandial dynamic effort.

  16. Selenium Pretreatment for Mitigation of Ischemia/Reperfusion Injury in Cardiovascular Surgery: Influence on Acute Organ Damage and Inflammatory Response.

    PubMed

    Steinbrenner, Holger; Bilgic, Esra; Pinto, Antonio; Engels, Melanie; Wollschläger, Lena; Döhrn, Laura; Kellermann, Kristine; Boeken, Udo; Akhyari, Payam; Lichtenberg, Artur

    2016-08-01

    Ischemia/reperfusion injury (IRI) contributes to morbidity and mortality after cardiovascular surgery requiring cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA). Multi-organ damage is associated with substantial decreases of blood selenium (Se) levels in patients undergoing cardiac surgery with CPB. We compared the influence of a dietary surplus of Se and pretreatment with ebselen, a mimic of the selenoenzyme glutathione peroxidase, on IRI-induced tissue damage and inflammation. Male Wistar rats were fed either a Se-adequate diet containing 0.3 ppm Se or supplemented with 1 ppm Se (as sodium selenite) for 5 weeks. Two other groups of Se-adequate rats received intraperitoneal injection of ebselen (30 mg/kg) or DMSO (solvent control) before surgery. The animals were connected to a heart-lung-machine and underwent 45 min of global ischemia during circulatory arrest at 16 °C, followed by re-warming and reperfusion. Selenite and ebselen suppressed IRI-induced leukocytosis and the increase in plasma levels of tissue damage markers (AST, ALT, LDH, troponin) during surgery but did not prevent the induction of proinflammatory cytokines (IL-6, TNF-α). Both Se compounds affected phosphorylation and expression of proteins related to stress response and inflammation: Ebselen increased phosphorylation of STAT3 transcription factor in the heart and decreased phosphorylation of ERK1/2 MAP kinases in the lungs. Selenite decreased ERK1/2 phosphorylation and HSP-70 expression in the heart. Pretreatment with selenite or ebselen protected against acute IRI-induced tissue damage during CPB and DHCA. Potential implications of their different actions with regard to molecular stress markers on the recovery after surgery represent promising targets for further investigation. PMID:27192987

  17. Society for Cardiovascular Angiography and Interventions

    MedlinePlus

    ... jointly produced, collaborated with, or endorsed by the Society of Cardiovascular Angiography and Interventions. Press & News » Review ... SCAI Member? Create an Account Advertisement Advertisement The Society for Cardiovascular Angiography and Interventions Foundation, 1100 17th ...

  18. A dose-response study of consuming high-fructose corn syrup–sweetened beverages on lipid/lipoprotein risk factors for cardiovascular disease in young adults123456

    PubMed Central

    Medici, Valentina; Bremer, Andrew A; Lee, Vivien; Lam, Hazel D; Nunez, Marinelle V; Chen, Guoxia X; Keim, Nancy L; Havel, Peter J

    2015-01-01

    Background: National Health and Nutrition Examination Survey data show an increased risk of cardiovascular disease (CVD) mortality with an increased intake of added sugar. Objective: We determined the dose-response effects of consuming beverages sweetened with high-fructose corn syrup (HFCS) at zero, low, medium, and high proportions of energy requirements (Ereq) on circulating lipid/lipoprotein risk factors for CVD and uric acid in adults [age: 18–40 y; body mass index (in kg/m2): 18–35]. Design: We conducted a parallel-arm, nonrandomized, double-blinded intervention study in which adults participated in 3.5 inpatient days of baseline testing at the University of California Davis Clinical and Translational Science Center’s Clinical Research Center. Participants then consumed beverages sweetened with HFCS at 0% (aspartame sweetened, n = 23), 10% (n = 18), 17.5% (n = 16), or 25% (n = 28) of Ereq during 13 outpatient days and during 3.5 inpatient days of intervention testing at the research center. We conducted 24-h serial blood collections during the baseline and intervention testing periods. Results: Consuming beverages containing 10%, 17.5%, or 25% Ereq from HFCS produced significant linear dose-response increases of lipid/lipoprotein risk factors for CVD and uric acid: postprandial triglyceride (0%: 0 ± 4; 10%: 22 ± 8; 17.5%: 25 ± 5: 25%: 37 ± 5 mg/dL, mean of Δ ± SE, P < 0.0001 effect of HFCS-dose), fasting LDL cholesterol (0%: −1.0 ± 3.1; 10%: 7.4 ± 3.2; 17.5%: 8.2 ± 3.1; 25%: 15.9 ± 3.1 mg/dL, P < 0.0001), and 24-h mean uric acid concentrations (0%: −0.13 ± 0.07; 10%: 0.15 ± 0.06; 17.5%: 0.30 ± 0.07; 25%: 0.59 ± 0.09 mg/dL, P < 0.0001). Compared with beverages containing 0% HFCS, all 3 doses of HFCS-containing beverages increased concentrations of postprandial triglyceride, and the 2 higher doses increased fasting and/or postprandial concentrations of non–HDL cholesterol, LDL cholesterol, apolipoprotein B, apolipoprotein CIII, and

  19. Autophagy in cardiovascular biology

    PubMed Central

    Lavandero, Sergio; Chiong, Mario; Rothermel, Beverly A.; Hill, Joseph A.

    2015-01-01

    Cardiovascular disease is the leading cause of death worldwide. As such, there is great interest in identifying novel mechanisms that govern the cardiovascular response to disease-related stress. First described in failing hearts, autophagy within the cardiovascular system has been widely characterized in cardiomyocytes, cardiac fibroblasts, endothelial cells, vascular smooth muscle cells, and macrophages. In all cases, a window of optimal autophagic activity appears to be critical to the maintenance of cardiovascular homeostasis and function; excessive or insufficient levels of autophagic flux can each contribute to heart disease pathogenesis. In this Review, we discuss the potential for targeting autophagy therapeutically and our vision for where this exciting biology may lead in the future. PMID:25654551

  20. Cardiovascular responses to lower body negative pressure before and after 4 h of head-down bed rest and seated control in men and women.

    PubMed

    Edgell, H; Grinberg, A; Gagné, N; Beavers, K R; Hughson, R L

    2012-11-01

    Cardiovascular deconditioning after a 4-h head-down bed rest (HDBR) might be a consequence of the time of day relative to pre-HDBR testing, or simply 4 h of confinement and inactivity rather than the posture change. Ten men and 11 women were studied during lower body negative pressure (LBNP) before and after 4-h HDBR and 4-h seated posture (SEAT) as a control for time of day and physical inactivity effects to test the hypotheses that cardiovascular deconditioning was a consequence of the HDBR posture, and that women would have a greater deconditioning response. Following HDBR, men and women had lower blood volume, higher heart rate with a greater increase during LBNP, a greater decrease of stroke volume during LBNP, lower central venous pressure, smaller inferior vena cava diameter, higher portal vein resistance index with a greater increase during LBNP, but lower forearm vascular resistance, lower norepinephrine, and lower renin. Women had lower vasopressin and men had higher vasopressin after HDBR, and women had lower pelvic impedance and men higher pelvic impedance. Following SEAT, brachial vascular resistance was reduced, thoracic impedance was elevated, the reduction of central venous pressure during LBNP was changed, women had higher angiotensin II whereas men had lower levels, and pelvic impedance increased in women and decreased in men. Cardiovascular deconditioning was greater after 4-h HDBR than after SEAT. Women and men had similar responses for most cardiovascular variables in the present study that tested the responses to LBNP after short-duration HDBR compared with a control condition. PMID:22984250

  1. Switchable and responsive liquid crystal-functionalized microfibers produced via coaxial electrospinning

    NASA Astrophysics Data System (ADS)

    Lagerwall, Jan P. F.

    2012-03-01

    "Wearable technology" or "smart textiles" are concepts that are very rapidly gaining in attention around the world, as industry as well as academia are making major advances in integrating advanced devices with various textiles around our household. The technological challenges involved in this development are however considerable, calling for new solutions, new materials and truly original thinking. An attractive approach to realize certain classes of wearable devices may be to use textile fibers functionalized by responsive materials such as liquid crystals, normally not connected to textiles. We can produce non-woven textiles with such fibers by means of electrospinning, a technique for producing very thin polymer fibers that can be uniform or with core-sheath geometries. Since the core can be made out of traditionally non-spinnable materials we can use coaxial electrospinning (one fluid spun inside another) to produce composite fibers with a core of liquid crystal inside a polymer sheath. The resulting fibers constitute an entirely new configuration for applying liquid crystals, giving the fibers functionality and responsiveness. For instance, with a cholesteric core we can produce non-woven mats with iridescent color that can be tuned (or removed) e.g. by heating or cooling. In this paper I describe our method of producing these novel functionalized fibers and their characterization, and I will discuss the directions for future research and application possibilities, e.g. in clothing-integrated sensors and indicators.

  2. Transcriptomic responses of the calanoid copepod Calanus finmarchicus to the saxitoxin producing dinoflagellate Alexandrium fundyense

    PubMed Central

    Roncalli, Vittoria; Cieslak, Matthew C.; Lenz, Petra H.

    2016-01-01

    In the Gulf of Maine, the copepod Calanus finmarchicus co-occurs with the neurotoxin-producing dinoflagellate, Alexandrium fundyense. The copepod is resistant to this toxic alga, but little is known about other effects. Gene expression profiles were used to investigate the physiological response of females feeding for two and five days on a control diet or a diet containing either a low or a high dose of A. fundyense. The physiological responses to the two experimental diets were similar, but changed between the time points. At 5-days the response was characterized by down-regulated genes involved in energy metabolism. Detoxification was not a major component of the response. Instead, genes involved in digestion were consistently regulated, suggesting that food assimilation may have been affected. Thus, predicted increases in the frequency of blooms of A. fundyense could affect C. finmarchicus populations by changing the individuals’ energy budget and reducing their ability to build lipid reserves. PMID:27181871

  3. L-Asparaginase II Produced by Salmonella Typhimurium Inhibits T Cell Responses and Mediates Virulence

    PubMed Central

    Kullas, Amy L.; McClelland, Michael; Yang, Hee-Jeong; Tam, Jason W.; Torres, AnnMarie; Porwollik, Steffen; Mena, Patricio; McPhee, Joseph B.; Bogomolnaya, Lydia; Andrews-Polymenis, Helene; van der Velden, Adrianus W.M.

    2013-01-01

    SUMMARY Salmonella enterica serovar Typhimurium avoids clearance by the host immune system by suppressing T cell responses; however, the mechanisms that mediate this immunosuppression remain unknown. We show that S. Typhimurium inhibit T cell responses by producing L-Asparaginase II, which catalyzes the hydrolysis of L-asparagine to aspartic acid and ammonia. L-Asparaginase II is necessary and sufficient to suppress T cell blastogenesis, cytokine production, and proliferation and to downmodulate expression of the T cell receptor. Furthermore, S. Typhimurium-induced inhibition of T cells in vitro is prevented upon addition of L-asparagine. S. Typhimurium lacking the L-Asparaginase II gene (STM3106) are unable to inhibit T cell responses and exhibit attenuated virulence in vivo. L-Asparaginases are used to treat acute lymphoblastic leukemia through mechanisms that likely involve amino acid starvation of leukemic cells, and these findings indicate that pathogens similarly use L-asparagine deprivation to limit T cell responses. PMID:23245323

  4. Transcriptomic responses of the calanoid copepod Calanus finmarchicus to the saxitoxin producing dinoflagellate Alexandrium fundyense.

    PubMed

    Roncalli, Vittoria; Cieslak, Matthew C; Lenz, Petra H

    2016-01-01

    In the Gulf of Maine, the copepod Calanus finmarchicus co-occurs with the neurotoxin-producing dinoflagellate, Alexandrium fundyense. The copepod is resistant to this toxic alga, but little is known about other effects. Gene expression profiles were used to investigate the physiological response of females feeding for two and five days on a control diet or a diet containing either a low or a high dose of A. fundyense. The physiological responses to the two experimental diets were similar, but changed between the time points. At 5-days the response was characterized by down-regulated genes involved in energy metabolism. Detoxification was not a major component of the response. Instead, genes involved in digestion were consistently regulated, suggesting that food assimilation may have been affected. Thus, predicted increases in the frequency of blooms of A. fundyense could affect C. finmarchicus populations by changing the individuals' energy budget and reducing their ability to build lipid reserves. PMID:27181871

  5. Short-term physiological responses of wild and hatchery-produced red drum during angling

    USGS Publications Warehouse

    Gallman, E.A.; Isely, J.J.; Tomasso, J.R.; Smith, T.I.J.

    1999-01-01

    Serum cortisol concentrations, plasma glucose concentrations, plasma lactate concentrations, and plasma osmolalities increased in red drum Sciaenops ocellatus (26.0-65.5 cm total length) during angling in estuarine waters (17-33 g/L salinity, 21-31??C). Angling time varied from as fast as possible (10 s) to the point when fish ceased resisting (up to 350 s). The increases in the physiological characteristics were similar in wild and hatchery-produced fish. This study indicates that hatchery-produced red drum may be used in catch-and-release studies to simulate the responses of wild fish.

  6. CRF1 and CRF2 receptors in the bed nucleus of the stria terminalis modulate the cardiovascular responses to acute restraint stress in rats.

    PubMed

    Oliveira, Leandro A; Almeida, Jeferson; Benini, Ricardo; Crestani, Carlos C

    2015-01-01

    The corticotropin-releasing factor (CRF) is involved in behavioral and physiological responses to emotional stress through its action in several limbic structures, including the bed nucleus of the stria terminalis (BNST). Nevertheless, the role of CRF1 and CRF2 receptors in the BNST in cardiovascular adjustments during aversive threat is unknown. Therefore, in the present study we investigated the involvement of CRF receptors within the BNST in cardiovascular responses evoked by acute restraint stress in rats. For this, we evaluated the effects of bilateral treatment of the BNST with selective agonists and antagonists of either CRF1 or CRF2 receptors in the arterial pressure and heart rate increase and the decrease in tail skin temperature induced by restraint stress. Microinjection of the selective CRF1 receptor antagonist CP376395 into the BNST reduced the pressor and tachycardiac responses caused by restraint. Conversely, BNST treatment with the selective CRF1 receptor agonist CRF increased restraint-evoked arterial pressure and HR responses and reduced the fall in tail skin temperature response. All effects of CRF were inhibited by local BNST pretreatment with CP376395. The selective CRF2 receptor antagonist antisalvagine-30 reduced the arterial pressure increase and the fall in tail skin temperature. The selective CRF2 receptor agonist urocortin-3 increased restraint-evoked pressor and tachycardiac responses and reduced the drop in cutaneous temperature. All effects of urocortin-3 were abolished by local BNST pretreatment with antisalvagine-30. These findings indicate an involvement of both CRF1 and CRF2 receptors in the BNST in cardiovascular adjustments during emotional stress. PMID:25829333

  7. Traditional games resulted in post-exercise hypotension and a lower cardiovascular response to the cold pressor test in healthy children

    PubMed Central

    Rauber, Suliane B.; Boullosa, Daniel A.; Carvalho, Ferdinando O.; de Moraes, José F. V. N.; de Sousa, Ioranny R. C.; Simões, Herbert G.; Campbell, Carmen S. G.

    2014-01-01

    The present study aimed to verify if blood pressure (BP) reactivity could be reduced through a previous single session of active playing when compared to sedentary leisure. Sixteen pre-pubertal healthy children participated in this study. After familiarization with procedures and anthropometric evaluation, participants performed three sessions in randomized order: (1) 30 min of traditional Brazilian games (PLAY); (2) 30 min of video game playing (DDR); and (3) 30 min of watching TV (TV). Each session lasted 80 min, being 10 min of rest; 30 min of intervention activity; and 40 min of recovery. After recovery, the Cold Pressor Test (CPT) was used for the assessment of acute cardiovascular reactivity. BP was recorded at 30 s and 1 min during the CPT. Analysis of variance showed post-exercise hypotension (PEH) only after PLAY, and that systolic and diastolic BP were significantly increased in all conditions during CPT. However, the magnitude of the CPT-induced BP response was significantly less in PLAY compared to DDR and TV. The PEH observed during recovery and the reduced BP response to CPT following playing traditional games may be due its higher cardiovascular and metabolic demand as was indicated by the increased heart rate, oxygen consumption, and BP. It was concluded that BP reactivity to stress may be reduced through a previous single session of traditional games and that PEH was recorded only after this exercise form. This benefit indicates a potential role of playing strategies for cardiovascular health in childhood. PMID:25009506

  8. Traditional games resulted in post-exercise hypotension and a lower cardiovascular response to the cold pressor test in healthy children.

    PubMed

    Rauber, Suliane B; Boullosa, Daniel A; Carvalho, Ferdinando O; de Moraes, José F V N; de Sousa, Ioranny R C; Simões, Herbert G; Campbell, Carmen S G

    2014-01-01

    The present study aimed to verify if blood pressure (BP) reactivity could be reduced through a previous single session of active playing when compared to sedentary leisure. Sixteen pre-pubertal healthy children participated in this study. After familiarization with procedures and anthropometric evaluation, participants performed three sessions in randomized order: (1) 30 min of traditional Brazilian games (PLAY); (2) 30 min of video game playing (DDR); and (3) 30 min of watching TV (TV). Each session lasted 80 min, being 10 min of rest; 30 min of intervention activity; and 40 min of recovery. After recovery, the Cold Pressor Test (CPT) was used for the assessment of acute cardiovascular reactivity. BP was recorded at 30 s and 1 min during the CPT. Analysis of variance showed post-exercise hypotension (PEH) only after PLAY, and that systolic and diastolic BP were significantly increased in all conditions during CPT. However, the magnitude of the CPT-induced BP response was significantly less in PLAY compared to DDR and TV. The PEH observed during recovery and the reduced BP response to CPT following playing traditional games may be due its higher cardiovascular and metabolic demand as was indicated by the increased heart rate, oxygen consumption, and BP. It was concluded that BP reactivity to stress may be reduced through a previous single session of traditional games and that PEH was recorded only after this exercise form. This benefit indicates a potential role of playing strategies for cardiovascular health in childhood. PMID:25009506

  9. [Immune response produced by anti-rabies vaccines in marmosets (Callithrix sp)].

    PubMed

    Andrade, M C; de Oliveira, A N; Romijn, P C; Kimura, L M

    1999-01-01

    In order to evaluate the immune response produced by rabies vaccines in new world nonhuman primates, thirty marmosets (Callithrix sp) were divided into five groups of six individuals and submitted to five different antirabies vaccination schemes using two distinct commercially available animal vaccines. The first was produced in suckling mouse brain (Fuenzalida and Palacios), and the second in NIL-2 cell culture. Post-vaccine serological monitoring was carried out periodically. The results showed that the Fuenzalida and Palacios vaccine was not able to protect the animals when using a single dose or even with a booster. But when submitted to a vaccination routine similar to that used for humans, the marmosets showed detectable antibodies, and only one succumbed to rabies after being challenged. In addition, the vaccine produced in NIL-2 cell culture induced high antibody levels in all vaccinated animals and all animals survived the viral challenge. PMID:10881088

  10. NMDA and non-NMDA glutamate receptors in the paraventricular nucleus of the hypothalamus modulate different stages of hemorrhage-evoked cardiovascular responses in rats.

    PubMed

    Busnardo, C; Crestani, C C; Fassini, A; Resstel, L B M; Corrêa, F M A

    2016-04-21

    Here we report the involvement of N-Methyl-d-Aspartate (NMDA) and non-NMDA glutamate receptors from the paraventricular nucleus of the hypothalamus (PVN) in the mediation of cardiovascular changes observed during hemorrhage and post-bleeding periods. In addition, the present study provides further evidence of the involvement of circulating vasopressin and cardiac sympathetic activity in cardiovascular responses to hemorrhage. Systemic treatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP (50 μg/kg, i.v.) increased the latency to the onset of hypotension during hemorrhage and slowed post-bleeding recovery of blood pressure. Systemic treatment with the β1-adrenergic receptor antagonist atenolol (1 mg/kg, i.v.) also increased the latency to the onset of hypotension during hemorrhage. Moreover, atenolol reversed the hemorrhage-induced tachycardia into bradycardia. Bilateral microinjection of the selective NMDA glutamate receptor antagonist LY235959 (2 nmol/100 nL) into the PVN blocked the hypotensive response to hemorrhage and reduced the tachycardia during the post-hemorrhage period. Systemic treatment with dTyr(CH2)5(Me)AVP inhibited the effect of LY235959 on hemorrhage-induced hypotension, without affecting the post-bleeding tachycardia. PVN treatment with the selective non-NMDA receptor antagonist NBQX (2 nmol/100 nL) reduced the recovery of blood pressure to normal levels in the post-bleeding phase and reduced hemorrhage-induced tachycardia. Combined blockade of both NMDA and non-NMDA glutamate receptors in the PVN completely abolished the hypotensive response in the hemorrhage period and reduced the tachycardiac response in the post-hemorrhage period. These results indicate that local PVN glutamate neurotransmission is involved in the neural pathway mediating cardiovascular responses to hemorrhage, via an integrated control involving autonomic nervous system activity and vasopressin release into the circulation. PMID:26861418

  11. Recycling research on spent fluorescent lamps on the basis of extended producer responsibility in China.

    PubMed

    Peng, Lihong; Wang, Yejun; Chang, Chang-Tang

    2014-11-01

    Mercury is a physiological toxin released by spent fluorescent lamps (SFLs) and is considered a serious pollutant. As the world's largest producer of fluorescent lamps, China suffers from SFL pollution because of inefficient recycling and management of SFLs. Drawing upon the most successful practices worldwide, this paper suggests the recycling of SFLs on the basis of the extended producer responsibility (EPR) system in China. Manufacturers and importers are the main parties responsible for the take-back, recycling, and disposal ofSFLs in the EPR system. In view of the situation in China and to address the objectives of the EPR system, this paper recommends the implementation of a third-party take-back mode for small- and medium-scale enterprises and of a takeback mode for large enterprises to be carried out by original equipment manufacturers. This paper suggests an extended responsibility fund to finance and support the SFL recycling system and discusses in detail the different recycling network systems and fund flows of the two take-back modes. By conducting a case study, the authors determine that the subsidy rate for SFLs that a recycling company can obtain from the extended responsibility fund for recycling and disposing of lamps can be set at $1.35/kg. The authors also predict the levy level that fluorescent lamp manufacturers must submit. PMID:25509551

  12. Subchronic toxicity and cardiovascular responses in spontaneously hypertensive rats after exposure to multiwalled carbon nanotubes by intratracheal instillation.

    PubMed

    Chen, Rui; Zhang, Lili; Ge, Cuicui; Tseng, Michael T; Bai, Ru; Qu, Ying; Beer, Christiane; Autrup, Herman; Chen, Chunying

    2015-03-16

    The tremendous demand of the market for carbon nanotubes has led to their massive production that presents an increasing risk through occupational exposure. Lung deposition of carbon nanotubes is known to cause acute localized pulmonary adverse effects. However, systemic cardiovascular damages associated with acute pulmonary lesion have not been thoroughly addressed. Four kinds of multiwalled carbon nanotubes (MWCNTs) with different lengths and/or iron contents were used to explore the potential subchronic toxicological effects in spontaneously hypertensive (SH) rats and normotensive control Wistar-Kyoto (WKY) rats after intratracheal instillation. MWCNTs penetrated the lung blood-gas barrier and accumulated in the liver, kidneys, and spleen but not in the heart and aorta of SH rats. The pulmonary toxicity and cardiovascular effects were assessed at 7 and 30 days postexposure. Compared to the WKY rats, transient influences on blood pressure and up to 30 days persistent decrease in the heart rate of SH rats were found by electrocardiogram monitoring. The subchronic toxicity, especially the sustained inflammation of the pulmonary and cardiovascular system, was revealed at days 7 and 30 in both SH and WKY rat models. Histopathological results showed obvious morphological lesions in abdominal arteries of SH rats 30 days after exposure. Our results suggest that more attention should be paid to the long-term toxic effects of MWCNTs, and particularly, occupationally exposed workers with preexisting cardiovascular diseases should be monitored more thoroughly. PMID:25580880

  13. Acute and delayed effects of intermittant ozone on cardiovascular and thermoregulatory responses of young and aged rats

    EPA Science Inventory

    Ozone (03) is associated with cardiovascular and respiratory diseases. The aged population is considered to be more sensitive to air pollutants but relatively few studies have demonstrated increased susceptibility in animal models of aging. To study the acute and delayed physiolo...

  14. Acoustic responses of monodisperse lipid-encapsulated microbubble contrast agents produced by flow focusing

    PubMed Central

    Kaya, Mehmet; Feingold, Steven; Hettiarachchi, Kanaka; Lee, Abraham P; Dayton, Paul A

    2010-01-01

    Lipid-encapsulated microbubbles are used as contrast agents in ultrasound imaging. Currently available commercially made contrast agents have a polydisperse size distribution. It has been hypothesised that improved imaging sensitivity could be achieved with a uniform microbubble radius. We have recently developed microfluidics technology to produce contrast agents with a nearly monodisperse distribution. In this manuscript, we analyze echo responses from individual microbubbles from monodisperse populations in order to establish the relationship between scattered echo, microbubble radius, and excitation frequency. Simulations of bubble response from a modified Rayleigh-Plesset type model corroborate experimental data. Results indicate that microbubble echo response can be greatly increased by optimal combinations of microbubble radius and acoustic excitation frequency. These results may have a significant impact in the formulation of contrast agents to improve ultrasonic sensitivity. PMID:21475641

  15. Preliminary Results from the Joint Russian and US Field Test: Measurement of Sensorimotor and Cardiovascular Responses Immediately Following Landing of the Soyuz Spacecraft

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Kozlovskaya, I. B.; Tomilovskaya, E. S.; Bloomberg, J. J.; Platts, S. H.; Rukavishnikov, I. V.; Fomina, E. V.; Stenger, M. B.; Lee, S. M. C.; Wood, S. J.; Mulavara, A. P.; Fieveson, A. H.; Cerisano, J. M.; Kofman, I. S.; Fisher, E. A.

    2013-01-01

    Ongoing collaborative research efforts between NASA's Neuroscience and Cardiovascular Laboratories, and the Institute of Biomedical Problems' (IBMP) Sensory-Motor and Countermeasures Laboratories have been measuring functional sensorimotor, cardiovascular and strength responses following bed rest, dry immersion, short duration (Space Shuttle) and long duration (Mir and International Space Station) space flights. While the unloading paradigms associated with dry immersion and bed rest have do serve as acceptable flight analogs, testing of crew responses following the long duration flights does not begin until a minimum of 24 hours after landing. As a result it is not possible to estimate the nonlinear trend of the early (<24 hr) recovery process nor is it possible to accurately assess the full impact of the decrements associated with long duration flight. To overcome these limitations both the Russian and U.S. sides have implemented testing at the time of landing and before the flight crews have left the landing site. By joint agreement this research effort has been identified as the functional Field Test (FT). For practical reasons the FT has been divided into two phases: the full FT and a preliminary pilot version (PFT) of the FT that is reduced in both length and scope. The primary goal of this research is to determine functional abilities in long duration space flight crews beginning as soon after landing as possible (< 2 hr) with one to three immediate follow-up measurements on the day of landing. This goal has both sensorimotor and cardiovascular elements including an evaluation of NASA's new anti-orthostatic compression garment as compared with the Russian Kentavr garment. Functional sensorimotor measurements will include, but are not limited to, assessment of hand/eye coordination, ability to egress from a seated position, walk normally without falling, measurement of dynamic visual acuity, ability to discriminate different forces generated with both the

  16. Changes in cholesterol homeostasis and acute phase response link pulmonary exposure to multi-walled carbon nanotubes to risk of cardiovascular disease.

    PubMed

    Poulsen, Sarah S; Saber, Anne T; Mortensen, Alicja; Szarek, Józef; Wu, Dongmei; Williams, Andrew; Andersen, Ole; Jacobsen, Nicklas R; Yauk, Carole L; Wallin, Håkan; Halappanavar, Sabina; Vogel, Ulla

    2015-03-15

    Adverse lung effects following pulmonary exposure to multi-walled carbon nanotubes (MWCNTs) are well documented in rodents. However, systemic effects are less understood. Epidemiological studies have shown increased cardiovascular disease risk after pulmonary exposure to airborne particles, which has led to concerns that inhalation exposure to MWCNTs might pose similar risks. We analyzed parameters related to cardiovascular disease, including plasma acute phase response (APR) proteins and plasma lipids, in female C57BL/6 mice exposed to a single intratracheal instillation of 0, 18, 54 or 162μg/mouse of small, entangled (CNTSmall, 0.8±0.1μm long) or large, thick MWCNTs (CNTLarge, 4±0.4μm long). Liver tissues and plasma were harvested 1, 3 and 28days post-exposure. In addition, global hepatic gene expression, hepatic cholesterol content and liver histology were used to assess hepatic effects. The two MWCNTs induced similar systemic responses despite their different physicochemical properties. APR proteins SAA3 and haptoglobin, plasma total cholesterol and low-density/very low-density lipoprotein were significantly increased following exposure to either MWCNTs. Plasma SAA3 levels correlated strongly with pulmonary Saa3 levels. Analysis of global gene expression revealed perturbation of the same biological processes and pathways in liver, including the HMG-CoA reductase pathway. Both MWCNTs induced similar histological hepatic changes, with a tendency towards greater response following CNTLarge exposure. Overall, we show that pulmonary exposure to two different MWCNTs induces similar systemic and hepatic responses, including changes in plasma APR, lipid composition, hepatic gene expression and liver morphology. The results link pulmonary exposure to MWCNTs with risk of cardiovascular disease. PMID:25620056

  17. Cardiovascular Pharmacogenomics: The Future of Cardiovascular Therapeutics?

    PubMed Central

    Roden, Dan M.

    2012-01-01

    Responses to drug therapy vary from benefit to no effect to adverse effects which can be serious or occasionally fatal. Increasing evidence supports the idea that genetic variants can play a major role in this spectrum of responses. Well-studied examples in cardiovascular therapeutics include predictors of steady-state warfarin dosage, predictors of reduced efficacy among patients receiving clopidogrel for drug eluting stents, and predictors of some serious adverse drug effects. This review summarizes contemporary approaches to identifying and validating genetic predictors of variability in response to drug treatment. Approaches to incorporating this new knowledge into clinical care, and the barriers to this concept, are addressed. PMID:23200096

  18. Bronchial Epithelial Cells Produce IL-5: Implications for Local Immune Responses in the Airways

    PubMed Central

    Wu, Carol A.; Peluso, John J.; Zhu, Li; Lingenheld, Elizabeth G.; Walker, Sharale T.; Puddington, Lynn

    2010-01-01

    IL-5 is a pleiotropic cytokine that promotes eosinophil differentiation and survival. While naïve bronchial epithelial cells (BEC) produce low levels of IL-5, the role of BEC-derived IL-5 in allergic airway inflammation is unknown. We now show that BEC, isolated from mice with OVA-induced allergic airway disease (AAD), produced elevated levels of IL-5 mRNA and protein as compared to BEC from naïve mice. To determine the contribution of BEC-derived IL-5 to effector responses in the airways, IL-5 deficient bone marrow chimeric mice were generated in which IL-5 expression was restricted to stromal (e.g. BEC) or hematopoietic cells. When subjected to AAD, IL-5 produced by BECs contributed to mucous metaplasia, airway eosinophilia, and OVA-specific IgA levels. Thus, IL-5 production by BEC can impact the microenvironment of the lung, modifying pathologic and protective immune responses in the airways. PMID:20494340

  19. New Delhi metallo-beta-lactamase 1-producing Enterobacteriaceae: emergence and response in Europe.

    PubMed

    Struelens, M J; Monnet, D L; Magiorakos, A P; Santos O'Connor, F; Giesecke, J

    2010-11-18

    Acquired carbapenemases confer extensive antibiotic resistance to Enterobacteriaceae and represent a public health threat. A novel acquired carbapenemase, New Delhi metallo-beta-lactamase 1 (NDM-1), has recently been described in the United Kingdom and Sweden, mostly in patients who had received care on the Indian subcontinent. We conducted a survey among 29 European countries (the European Union Member States, Iceland and Norway) to gather information on the spread of NDM-1-producing Enterobacteriaceae in Europe, on public health responses and on available national guidance on detection, surveillance and control. A total of 77 cases were reported from 13 countries from 2008 to 2010. Klebsiella pneumoniae was the most frequently reported species with 54%. Among 55 cases with recorded travel history, 31 had previously travelled or been admitted to a hospital in India or Pakistan and five had been hospitalised in the Balkan region. Possible nosocomial acquisition accounted for 13 of 77 cases. National guidance on NDM-1 detection was available in 14 countries and on NDM-1 control in 11 countries. In conclusion, NDM-1 is spreading across Europe, where it is frequently linked to a history of healthcare abroad, but also to emerging nosocomial transmission. National guidance in response to the threat of carbapenemase-producing Enterobacteriaceae is available in approximately half of the surveyed European countries. Surveillance of carbapenemase- producing Enterobacteriaceae must be enhanced in Europe and effective control measures identified and implemented. PMID:21144431

  20. Changes in cholesterol homeostasis and acute phase response link pulmonary exposure to multi-walled carbon nanotubes to risk of cardiovascular disease

    SciTech Connect

    Poulsen, Sarah S.; Saber, Anne T.; Mortensen, Alicja; Szarek, Józef; Wu, Dongmei; Williams, Andrew; Andersen, Ole; Jacobsen, Nicklas R.; Yauk, Carole L.; Wallin, Håkan; Halappanavar, Sabina; Vogel, Ulla

    2015-03-15

    Adverse lung effects following pulmonary exposure to multi-walled carbon nanotubes (MWCNTs) are well documented in rodents. However, systemic effects are less understood. Epidemiological studies have shown increased cardiovascular disease risk after pulmonary exposure to airborne particles, which has led to concerns that inhalation exposure to MWCNTs might pose similar risks. We analyzed parameters related to cardiovascular disease, including plasma acute phase response (APR) proteins and plasma lipids, in female C57BL/6 mice exposed to a single intratracheal instillation of 0, 18, 54 or 162 μg/mouse of small, entangled (CNT{sub Small}, 0.8 ± 0.1 μm long) or large, thick MWCNTs (CNT{sub Large}, 4 ± 0.4 μm long). Liver tissues and plasma were harvested 1, 3 and 28 days post-exposure. In addition, global hepatic gene expression, hepatic cholesterol content and liver histology were used to assess hepatic effects. The two MWCNTs induced similar systemic responses despite their different physicochemical properties. APR proteins SAA3 and haptoglobin, plasma total cholesterol and low-density/very low-density lipoprotein were significantly increased following exposure to either MWCNTs. Plasma SAA3 levels correlated strongly with pulmonary Saa3 levels. Analysis of global gene expression revealed perturbation of the same biological processes and pathways in liver, including the HMG-CoA reductase pathway. Both MWCNTs induced similar histological hepatic changes, with a tendency towards greater response following CNT{sub Large} exposure. Overall, we show that pulmonary exposure to two different MWCNTs induces similar systemic and hepatic responses, including changes in plasma APR, lipid composition, hepatic gene expression and liver morphology. The results link pulmonary exposure to MWCNTs with risk of cardiovascular disease. - Highlights: • Systemic and hepatic alterations were evaluated in female mice following MWCNT instillation. • Despite being physicochemically

  1. Comparison of the effects of remifentanil andalfentanil on cardiovascular response to nasotracheal intubation: A prospective, randomized, double-blind study

    PubMed Central

    Olmez, Gonul; Ali Ozyilmaz, Mehmet; Menekse, Ali

    2005-01-01

    Background: Nasotracheal intubation is often necessary in patients undergoingelective or emergency maxillofacial surgery. Previous studies have suggested that the increase in blood pressure after nasotracheal intubation is significantly greater than the increase after orotracheal intubation. Many drugs, including narcotic analgesics, are effective in modifying cardiovascular responses to orotracheal intubation. Objective: The effects of remifentanil and alfentanil on the cardiovascularresponses to nasotracheal intubation were compared in healthy patients scheduled to undergo surgery. Methods: This prospective, randomized, double-blind study was conductedat the Department of Anesthesiology and Reanimation, Faculty of Medicine, Dicle University, Diyarbakir, Turkey. Patients aged 16 to 65 years scheduled to undergo elective maxillofacial surgery and who were American Society of Anesthesiologists status I or 11 were randomly assigned to receive remifentanil 1 μg/kg in 10 mL saline over 30 seconds followed by an infusion of 0.5 μg/kg · min, or alfentanil 10 μg/kg in 10 mL saline over 30 seconds followed by an infusion of saline. Anesthesia was then induced with propofol, cisatracurium, and 1% isoflurane with 66% nitrous oxide in oxygen. Heart rate (HR) and systolic and diastolic arterial pressures (SAP and DAP, respectively) were measured noninvasively at 2 minutes before general anesthesia induction (baseline); 2 minutes after induction; and 1, 3, and 5 minutes after nasotracheal intubation. Patients were monitored for cardiac changes using electrocardiography. Results: Forty consecutive patients were enrolled in the study. Twenty patients (11 males, 9 females; mean [SD] age, 27.7 [12.6] years) received remifentanil, and 20 patients (12 males, 8 females; mean [SD] age, 31.5 [17.2] years) received alfentanil. Two minutes after anesthesia induction, mean (SD) arterial pressures decreased significantly from baseline in the remifentanil group (changes, 22 [8]/11 [6] mm

  2. Keratinocytes produce IL-6 in response to desmoglein 1 cleavage by Staphylococcus aureus exfoliative toxin A.

    PubMed

    Rolle, Cleo E; Chen, Juan; Pastar, Irena; Cardenas, Tatiana C P; Perez, Roberto; Hower, Suzanne; Ferracci, Franco; Snyder, Richard; Tomic-Canic, Marjana; Plano, Lisa R W

    2013-12-01

    Many skin infections are caused by Staphylococcus aureus, a bacterial pathogen that produces virulence factors associated with these conditions such as exfoliative toxins A and B (ETA, ETB) and the leukotoxin Panton-Valentine leukocidin (PVL). Herein, we examine the potential of skin-infecting S. aureus to produce virulence factors and their impact on the local immune response. Toxin gene profiles were generated from 188 S. aureus isolated as single infecting organisms from skin lesions and demonstrated a higher potential to express ETA, ETB, and PVL than community isolates (p < 0.001). Within the study isolate group, the prevalence of genes encoding PVL was higher among methicillin-resistant S. aureus (MRSA; n = 49), while genes encoding ETs were more prevalent in methicillin-susceptible S. aureus (MSSA; n = 139). When lesion-associated white blood cell (WBC) counts were dichotomized into high- or low-WBC-count-associated bacteria, the gene for ETA was found to be associated with a low WBC count among MSSA (p = 0.001). The ETA-induced mouse model of staphylococcal scalded skin syndrome was used to investigate the link between ETA and cytokine production. Elevated IL-6 levels in the serum and increased expression of IL-6 mRNA in the skin were detected in response to ETA exposure. These findings were recapitulated in vitro using primary human keratinocytes. Thus, S. aureus may influence the local immune response via ETA cleavage of desmoglein 1 and the induction of cutaneous IL-6 expression. PMID:24287883

  3. Proteomic Analysis of Erythritol-Producing Yarrowia lipolytica from Glycerol in Response to Osmotic Pressure.

    PubMed

    Yang, Li-Bo; Dai, Xiao-Meng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2015-07-01

    Osmotic pressure is a critical factor for erythritol production with osmophilic yeast. Protein expression patterns of an erythritol-producing yeast, Yarrowia lipolytica, were analyzed to identify differentially-expressed proteins in response to osmotic pressure. In order to analyze intracellular protein levels quantitatively, two-dimensional gel electrophoresis was performed to separate and visualize the differential expression of the intracellular proteins extracted from Y. lipolytica cultured under low (3.17 osmol/kg) and high (4.21 osmol/kg) osmotic pressures. Proteomic analyses allowed identification of 54 differentially-expressed proteins among the proteins distributed in the range of pI 3-10 and 14.4-97.4 kDa molecular mass between the osmotic stress conditions. Remarkably, the main proteins were involved in the pathway of energy, metabolism, cell rescue, and stress response. The expression of such enzymes related to protein and nucleotide biosynthesis was inhibited drastically, reflecting the growth arrest of Y. lipolytica under hyperosmotic stress. The improvement of erythritol production under high osmotic stress was due to the significant induction of a range of crucial enzymes related to polyols biosynthesis, such as transketolase and triosephosphate isomerase, and the osmotic stress responsive proteins like pyridoxine-4-dehydrogenase and the AKRs family. The polyols biosynthesis was really related to an osmotic response and a protection mechanism against hyperosmotic stress in Y. lipolytica. Additionally, the high osmotic stress could also induce other cell stress responses as with heat shock and oxidation stress responses, and these responsive proteins, such as the HSPs family, catalase T, and superoxide dismutase, also had drastically increased expression levels under hyperosmotic pressure. PMID:25737116

  4. Endogenously produced 20-HETE modulates myogenic and TGF response in microperfused afferent arterioles.

    PubMed

    Ge, Ying; Murphy, Sydney R; Lu, Yan; Falck, John; Liu, Ruisheng; Roman, Richard J

    2013-01-01

    Previous studies have indicated that 20-hydroxyeicosatetraeonic acid (20-HETE) modulates vascular tone in large cerebral and renal arteries through inhibition of the large conductance, calcium sensitive potassium (BK) channel activity. However, the role of 20-HETE in modulating tubuloglomerular feedback (TGF) and the myogenic response in the afferent arteriole (Af-Art) is unknown. The present study examined the effects of inhibitors of the synthesis and action of 20-HETE on the myogenic and TGF responses of isolated rabbit and mouse Af-Arts. Luminal diameter decreased by 9.2±0.5% in mice and 8.9±1.3% in rabbit Af-Art when the perfusion pressure was increased from 60 to 120 mmHg. Administration of a 20-HETE synthesis inhibitor, HET0016 (1 μM), or a selective 20-HETE antagonist, 6, 15-20-hydroxyeicosadienoic acid (6, 15-20-HEDE, 10 μM) completely blocked the myogenic response of both rabbit and mouse Af-Art, while addition of 5, 14-20-HEDE (10 μM), a 20-HETE agonist, restored the myogenic response in vessels treated with HET0016. Increases in NaCl concentration from 10 to 80 mM of the solution perfusing the macula densa constricted the Af-Art of rabbits by 6.0±1.4 μm (n=5). Addition of a 20-HETE agonist to the tubular perfusate potentiated the TGF-mediated vasoconstrictor response. This response was blocked by addition of a 20-HETE antagonist (6, 15-20-HEDE, 10 μM) to the vascular perfusate. These studies indicate that locally produced 20-HETE plays an important role in modulating the myogenic and TGF responsiveness of the Af-Art and may help explain how deficiencies in the renal formation of 20-HETE could promote the development of hypertension induced glomerular injury. PMID:23500064

  5. Advancing cardiovascular tissue engineering

    PubMed Central

    Truskey, George A.

    2016-01-01

    Cardiovascular tissue engineering offers the promise of biologically based repair of injured and damaged blood vessels, valves, and cardiac tissue. Major advances in cardiovascular tissue engineering over the past few years involve improved methods to promote the establishment and differentiation of induced pluripotent stem cells (iPSCs), scaffolds from decellularized tissue that may produce more highly differentiated tissues and advance clinical translation, improved methods to promote vascularization, and novel in vitro microphysiological systems to model normal and diseased tissue function. iPSC technology holds great promise, but robust methods are needed to further promote differentiation. Differentiation can be further enhanced with chemical, electrical, or mechanical stimuli. PMID:27303643

  6. Cardiovascular response to physical exercise in adult patients after atrial correction for transposition of the great arteries assessed with magnetic resonance imaging

    PubMed Central

    Roest, A A W; Lamb, H J; van der Wall, E E; Vliegen, H W; van den Aardweg, J G; Kunz, P; de Roos, A; Helbing, W A

    2004-01-01

    Objective: To assess with magnetic resonance imaging (MRI) cardiovascular function in response to exercise in patients after atrial correction of transposition of the great arteries (TGA). Methods: Cardiac function at rest and during submaximal exercise was assessed with MRI in 27 patients with TGA (mean (SD) age 26 (5) years) late (23 (2) years) after atrial correction and in 14 control participants (25 (5) years old). Results: At rest, only right ventricular ejection fraction was significantly lower in patients than in controls (56 (7)% v 65 (7)%, p < 0.05). In response to exercise, increases in right ventricular end diastolic (155 (55) ml to 163 (57) ml, p < 0.05) and right ventricular end systolic volumes (70 (34) ml to 75 (36) ml, p < 0.05) were observed in patients. Furthermore, right and left ventricular stroke volumes and ejection fraction did not increase significantly in patients. Changes in right ventricular ejection fraction with exercise correlated with diminished exercise capacity (r  =  0.43, p < 0.05). Conclusions: In patients with atrially corrected TGA, MRI showed an abnormal response to exercise of both systemic right and left ventricles. Exercise MRI provides a tool for close monitoring of cardiovascular function in these patients, who are at risk for late death. PMID:15145879

  7. Pulmonary oedema produced by scorpion venom augments a phenyldiguanide-induced reflex response in anaesthetized rats

    PubMed Central

    Deshpande, S B; Bagchi, S; Rai, O P; Aryya, N C

    1999-01-01

    The involvement of pulmonary oedema produced by scorpion venom in augmenting a phenyldiguanide (PDG)-induced reflex response was evaluated in urethane-anaesthetized rats. PDG-induced bradycardiac, hypotensive and apnoeic responses, expressed as time–response area, exhibited similarities before or after venom treatment. Hence, the time–response area of bradycardia was taken as a reflex parameter. Pulmonary oedema was determined by physical evaporation and histological methods. Exposure to Indian red scorpion (Buthus tamulus, BT; i.v.) venom for 30 min increased the pulmonary water content (P < 0.05; Student's t test) and augmented the PDG-induced bradycardiac reflex response by more than 2 times (P < 0.001). The increase of pulmonary water content was maximal with 100 μg kg−1 of venom and the augmentation was maximal with 10 μg kg−1. In a separate series of experiments, the venom (100 μg kg−1)-induced pulmonary oedema was confirmed by histological and physical methods. In this group also, the venom augmented the reflex to the same magnitude. Pulmonary oedema (physical and histological) and augmentation of the bradycardiac reflex response after BT venom (100 μg kg−1; i.v.) were absent in animals pretreated with aprotinin, a kallikrein-kinin inhibitor (6000 KIU; i.v.). Ondansetron (10 μg kg−1; i.v.), a 5-HT3 receptor antagonist, failed to block the venom-induced pulmonary oedema (physical and histological) but blocked the venom-induced augmentation of the reflex. The results of this study indicate that the venom-induced augmentation of the PDG reflex is associated with pulmonary oedema involving kinins utilizing 5-HT3 receptors. PMID:10581322

  8. Dose-Response Relationship of Physical Activity to Premature and Total All-Cause and Cardiovascular Disease Mortality in Walkers

    PubMed Central

    Williams, Paul T.

    2013-01-01

    Purpose To assess the dose-response relationships between cause-specific mortality and exercise energy expenditure in a prospective epidemiological cohort of walkers. Methods The sample consisted of the 8,436 male and 33,586 female participants of the National Walkers' Health Study. Walking energy expenditure was calculated in metabolic equivalents (METs, 1 MET = 3.5 ml O2/kg/min), which were used to divide the cohort into four exercise categories: category 1 (≤1.07 MET-hours/d), category 2 (1.07 to 1.8 MET-hours/d), category 3 (1.8 to 3.6 MET-hours/d), and category 4 (≥3.6 MET-hours/d). Competing risk regression analyses were use to calculate the risk of mortality for categories 2, 3 and 4 relative to category 1. Results 22.9% of the subjects were in category 1, 16.1% in category 2, 33.3% in category 3, and 27.7% in category 4. There were 2,448 deaths during the 9.6 average years of follow-up. Total mortality was 11.2% lower in category 2 (P = 0.04), 32.4% lower in category 3 (P<10−12) and 32.9% lower in category 4 (P = 10−11) than in category 1. For underlying causes of death, the respective risk reductions for categories 2, 3 and 4 were 23.6% (P = 0.008), 35.2% (P<10−5), and 34.9% (P = 0.0001) for cardiovascular disease mortality; 27.8% (P = 0.18), 20.6% (P = 0.07), and 31.4% (P = 0.009) for ischemic heart disease mortality; and 39.4% (P = 0.18), 63.8% (P = 0.005), and 90.6% (P = 0.002) for diabetes mortality when compared to category 1. For all related mortality (i.e., underlying and contributing causes of death combined), the respective risk reductions for categories 2, 3 and 4 were 18.7% (P = 0.22), 42.5% (P = 0.001), and 57.5% (P = 0.0001) for heart failure; 9.4% (P = 0.56), 44.3% (P = 0.0004), and 33.5% (P = 0.02) for hypertensive diseases; 11.5% (P = 0.38), 41.0% (P<10−4), and 35.5% (P = 0.001) for dysrhythmias: and 23.2% (P = 0.13), 45.8% (P = 0.0002), and 41

  9. Producer responsibility for e-waste management: key issues for consideration - learning from the Swiss experience.

    PubMed

    Khetriwal, Deepali Sinha; Kraeuchi, Philipp; Widmer, Rolf

    2009-01-01

    E-waste, a relatively recent addition to the waste stream in the form of discarded electronic and electric equipment, is getting increasing attention from policy makers as the quantity being generated is rising rapidly. One of the most promising policy options to address this issue is to extend the producers responsibility for their products beyond the point of sale, until end-of-product-life. This paper briefly introduces the concept of extended producer responsibility (EPR) and its applicability in the area of the end-of-life management of electronic and electrical equipment (EEE). It then examines the decade-long experience of Switzerland in using EPR to manage its e-waste, elaborating on the experience of the Swiss system in overcoming specific issues, and finally wrapping up with a synopsis of the lessons for policy makers. We consider each issue as an enquiry of questions confronting a policy maker and the choices that may present themselves. The five issues discussed are: (i) the challenges in getting an EPR based system started; (ii) securing financing to ensure a self-sustaining and smooth functioning system; (iii) organising a logistics network for the take back and collection of the e-waste; (iv) ensuring compliance of the various actors involved; and finally (v) reducing the threat of monopolistic practices. PMID:18162284

  10. Involvement of non-NMDA glutamate receptors of the hypothalamic paraventricular nucleus in the cardiovascular response to the microinjection of noradrenaline into the dorsal periaqueductal gray area of rats.

    PubMed

    Pelosi, Gislaine Garcia; Busnardo, Cristiane; Tavares, Rodrigo Fiacadori; Corrêa, Fernando Morgan Aguiar

    2015-03-30

    The dorsal periaqueductal gray area (dPAG) is involved in cardiovascular modulation. In a previous study, we showed that noradrenaline (NA) microinjected into the dPAG caused a vasopressin-mediated pressor response, involving a relay in the hypothalamic paraventricular nucleus (PVN). In the present study, we evaluated the involvement of ionotropic glutamate receptors within the PVN in the cardiovascular response to NA microinjection into the dPAG of unanesthetized rats. Microinjection of the selective NMDA glutamate receptor antagonist LY235959 (2nmol/100nL) unilaterally into the PVN did not affect the cardiovascular response evoked by microinjection of NA (15nmol/50nL) into the dPAG. On the other hand, unilateral PVN pretreatment with the non-NMDA glutamate receptor antagonist NBQX (2nmol/100nL) significantly reduced the pressor and cardiac response caused by microinjection of NA into the dPAG. In addition, bilateral PVN pretreatment with NBQX (2nmol/100nL) blocked the cardiovascular response to NA injected into the dPAG. In conclusion, the present results suggest that bilateral PVN activation of non-NMDA glutamate receptors mediates the vasopressin-related cardiovascular response to the microinjection of NA into the dPAG. PMID:25617821

  11. Dynamic changes in the relationship of microglia to cardiovascular neurons in response to increases and decreases in blood pressure.

    PubMed

    Kapoor, Komal; Bhandare, Amol M; Nedoboy, Polina E; Mohammed, Suja; Farnham, Melissa M J; Pilowsky, Paul M

    2016-08-01

    Microglia are present throughout the central nervous system (CNS) and express receptors for every known neurotransmitter. During inflammation, microglia change into a state that either promotes removal of debris (M1), or into a state that promotes soothing (M2). Caudal- and rostral- ventrolateral medullary regions (CVLM and RVLM, respectively) of the brainstem are key nuclei involved in all aspects of the cardiovascular system. In this study, we investigate a novel role for microglia in cardiovascular control in the brainstem of adult male Sprague-Dawley (SD) rat. Here we show, that increases and decreases in blood pressure (BP) triggers alertness in the physiology of microglia in the brainstem region; inducing changes in microglial spatial distribution and the number of synapses in contact with microglial end processes. Following 6h of acute hypertension, the number of synapses in contact with microglia increased by ≈30% in both regions of the brainstem, CVLM and RVLM. Induction of acute hypotension for 6h causes microglia to reduce the number of synaptic contacts by >20% in both, CVLM and RVLM, nuclei of the brainstem. Our analysis of the morphological characteristics of microglia, and expression levels of M1 and M2, reveals that the changes induced in microglial behavior do not require any obvious dramatic changes in their morphology. Taken together, our findings suggest that microglia play a novel, unexpected, physiological role in the uninjured autonomic nuclei of CNS; we therefore speculate that microglia act cooperatively with brainstem cardiovascular neurons to maintain them in a physiologically receptive state. PMID:27155147

  12. Identification of an IFN-gamma-producing neutrophil early in the response to Listeria monocytogenes.

    PubMed

    Yin, Jiyi; Ferguson, Thomas A

    2009-06-01

    IFN-gamma plays a critical role during the immune response to infection with Listeria monocytogenes. Early in the innate response NK cells are thought to be a primary source of IFN-gamma; however, protection can be mediated by the presence of significant numbers of primed IFN-gamma-secreting CD8(+) T cells. In this report, we examined the early response to Listeria and found that 18 h after infection spleens contain CD11b(+), Gr-1(high), or Ly6G(+) cells that produce significant IFN-gamma. Morphological analysis of sorted Gr-1(high)IFN-gamma(+) and Gr-1(low)IFN-gamma(+) or Ly6G(+)IFN-gamma(+) cells confirmed that these cells were neutrophils. The importance of IFN-gamma production by these cells was further tested using adoptive transfer studies. Transfer of purified neutrophils from Ifng(+/+) mice led to increased bacterial clearance in Ifng(-/-) mice. Transfer of Ifng(-/-) neutrophils provided no such protection. We conclude that neutrophils are an early source of IFN-gamma during Listeria infection and are important in providing immune protection. PMID:19454704

  13. Opioid and non-opioid central cardiovascular effects of ketamine.

    PubMed

    Seth, S; Mukherjee, D; Choudhary, A K; Sinha, J N; Gurtu, S

    1990-11-01

    The cardiovascular responses to ketamine injected intracisternally were examined in chloralose anaesthetized cats. Blood pressure and heart rate were recorded at different time intervals after intracisternal injection of drug or saline vehicle. The low doses of ketamine (0.5 or 1.0 mg) elicited dose dependent increase in blood pressure and heart rate. In contrast the high dose of ketamine (4 mg), produced a fall in blood pressure and heart rate. The cardiovascular response elicited by the low dose was naloxone insensitive and completely blocked by haloperidol, but not by dopamine antagonist pimozide. The vasodepressor and bradycardiac effect of the 4 mg dose was naloxone antagonizable. These data show that excitatory cardiovascular effects of the low dose result from a naloxone resistant site while in high doses an inhibitory effect is elicited by action at naloxone sensitive opiate receptors. PMID:1965327

  14. Cardiovascular Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cardiovascular disease (CVD), particularly CHD (coronary heart disease) and stroke, remain the leading causes of death of women in America and most developed countries. In recent years the rate of CVD has declined in men but not in women. This is contributed to by an under-recognition of women’s C...

  15. Cardiovascular system

    MedlinePlus Videos and Cool Tools

    The cardiovascular system is composed of the heart and the network of arteries, veins, and capillaries that transport blood throughout the body. The ... which they are eliminated. Most of the blood is made up of a watery, protein-laden fluid ...

  16. Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies

    PubMed Central

    Keum, NaNa; Giovannucci, Edward; Fadnes, Lars T; Boffetta, Paolo; Greenwood, Darren C; Tonstad, Serena; Vatten, Lars J; Riboli, Elio; Norat, Teresa

    2016-01-01

    Objective To quantify the dose-response relation between consumption of whole grain and specific types of grains and the risk of cardiovascular disease, total cancer, and all cause and cause specific mortality. Data sources PubMed and Embase searched up to 3 April 2016. Study selection Prospective studies reporting adjusted relative risk estimates for the association between intake of whole grains or specific types of grains and cardiovascular disease, total cancer, all cause or cause specific mortality. Data synthesis Summary relative risks and 95% confidence intervals calculated with a random effects model. Results 45 studies (64 publications) were included. The summary relative risks per 90 g/day increase in whole grain intake (90 g is equivalent to three servings—for example, two slices of bread and one bowl of cereal or one and a half pieces of pita bread made from whole grains) was 0.81 (95% confidence interval 0.75 to 0.87; I2=9%, n=7 studies) for coronary heart disease, 0.88 (0.75 to 1.03; I2=56%, n=6) for stroke, and 0.78 (0.73 to 0.85; I2=40%, n=10) for cardiovascular disease, with similar results when studies were stratified by whether the outcome was incidence or mortality. The relative risks for morality were 0.85 (0.80 to 0.91; I2=37%, n=6) for total cancer, 0.83 (0.77 to 0.90; I2=83%, n=11) for all causes, 0.78 (0.70 to 0.87; I2=0%, n=4) for respiratory disease, 0.49 (0.23 to 1.05; I2=85%, n=4) for diabetes, 0.74 (0.56 to 0.96; I2=0%, n=3) for infectious diseases, 1.15 (0.66 to 2.02; I2=79%, n=2) for diseases of the nervous system disease, and 0.78 (0.75 to 0.82; I2=0%, n=5) for all non-cardiovascular, non-cancer causes. Reductions in risk were observed up to an intake of 210-225 g/day (seven to seven and a half servings per day) for most of the outcomes. Intakes of specific types of whole grains including whole grain bread, whole grain breakfast cereals, and added bran, as well as total bread and total breakfast cereals were also associated

  17. Activation of GABAA or 5HT1A receptors in the raphé pallidus abolish the cardiovascular responses to exogenous stress in conscious rats.

    PubMed

    Pham-Le, Nhut Minh; Cockburn, Chelsea; Nowell, Katherine; Brown, Justin

    2011-11-25

    Dysfunction in serotonin (5HT) neurotransmission in the brainstem of infants may disrupt protective responses to stress and increase the risk for Sudden Infant Death Syndrome (SIDS). The raphé pallidus (NRP) and other brainstem nuclei are rich in 5HT and are thought to mediate stress responses, including increases in blood pressure (BP) and heart rate (HR). Determining how 5HT neurotransmission in the brainstem mediates responses to stress will help to explain how dysfunction in neurotransmission could increase the risk of SIDS. It was hypothesized that alterations in neurotransmission in the NRP, specifically activation of the 5HT(1A) receptor subtype, would block cardiovascular responses to various types of exogenous stress. Using aseptic techniques, male Sprague-Dawley rats were instrumented with radiotelemetry probes which enabled non-invasive measurement of BP and HR. An indwelling microinjection cannula was also stereotaxically implanted into the NRP for injection of drugs that altered local 5HT neurotransmission. Following a one week recovery period, rats were microinjected with either muscimol (GABA(A) receptor agonist), 8-OH-DPAT (agonist to the inhibitory 5HT(1A) receptor), or a vehicle control (artificial cerebral spinal fluid; ACSF) immediately prior to exposure to one of three stressors: handling, air jet, or restraint. Physical handling and restraint of the animal were designed to elicit a mild and a maximal stress response respectively; while an air jet directed at the rat's face was used to provoke a psychological stress that did not require physical contact. All three stressors elicited similar and significant elevations in HR and BP following ACSF that persisted for at least 15 min with BP and HR elevated by ∼14.0 mmHg and ∼56.3 bpm respectively. The similarity in the stress responses suggest even mild handling of a rat elicits a maximal sympathoexcitatory response. The stress response was abolished following 8-OH-DPAT or muscimol

  18. Cardiovascular and sympathetic neural responses to handgrip and cold pressor stimuli in humans before, during and after spaceflight

    NASA Technical Reports Server (NTRS)

    Fu, Qi; Levine, Benjamin D.; Pawelczyk, James A.; Ertl, Andrew C.; Diedrich, Andre; Cox, James F.; Zuckerman, Julie H.; Ray, Chester A.; Smith, Michael L.; Iwase, Satoshi; Saito, Mitsuru; Sugiyama, Yoshiki; Mano, Tadaaki; Zhang, Rong; Iwasaki, Kenichi; Lane, Lynda D.; Buckey, Jay C Jr; Cooke, William H.; Robertson, Rose Marie; Baisch, Friedhelm J.; Blomqvist, C. Gunnar; Eckberg, Dwain L.; Robertson, David; Biaggioni, Italo

    2002-01-01

    Astronauts returning to Earth have reduced orthostatic tolerance and exercise capacity. Alterations in autonomic nervous system and neuromuscular function after spaceflight might contribute to this problem. In this study, we tested the hypothesis that exposure to microgravity impairs autonomic neural control of sympathetic outflow in response to peripheral afferent stimulation produced by handgrip and a cold pressor test in humans. We studied five astronauts approximately 72 and 23 days before, and on landing day after the 16 day Neurolab (STS-90) space shuttle mission, and four of the astronauts during flight (day 12 or 13). Heart rate, arterial pressure and peroneal muscle sympathetic nerve activity (MSNA) were recorded before and during static handgrip sustained to fatigue at 40 % of maximum voluntary contraction, followed by 2 min of circulatory arrest pre-, in- and post-flight. The cold pressor test was applied only before (five astronauts) and during flight (day 12 or 13, four astronauts). Mean (+/- S.E.M.) baseline heart rates and arterial pressures were similar among pre-, in- and post-flight measurements. At the same relative fatiguing force, the peak systolic pressure and mean arterial pressure during static handgrip were not different before, during and after spaceflight. The peak diastolic pressure tended to be higher post- than pre-flight (112 +/- 6 vs. 99 +/- 5 mmHg, P = 0.088). Contraction-induced rises in heart rate were similar pre-, in- and post-flight. MSNA was higher post-flight in all subjects before static handgrip (26 +/- 4 post- vs. 15 +/- 4 bursts min(-1) pre-flight, P = 0.017). Contraction-evoked peak MSNA responses were not different before, during, and after spaceflight (41 +/- 4, 38 +/- 5 and 46 +/- 6 bursts min(-1), all P > 0.05). MSNA during post-handgrip circulatory arrest was higher post- than pre- or in-flight (41 +/- 1 vs. 33 +/- 3 and 30 +/- 5 bursts min(-1), P = 0.038 and 0.036). Similarly, responses of MSNA and blood pressure

  19. Human cardiovascular and vestibular responses in long minutes and low +Gz loading by a short arm centrifuge

    NASA Astrophysics Data System (ADS)

    Yajima, K.; Miyamoto, A.; Ito, M.; Maru, R.; Maeda, T.; Sanada, E.; Nakazato, T.; Saiki, C.; Yamaguchi, Y.; Igarashi, M.; Matsumoto, S.

    1.4 G, 1.7 G, and 2.0 G of +Gz and 60 minutes centrifugation was adopted to 20 healthy male subjects using 1.8 m radius centrifuge equipped to Nihon University School of Medicine. G was applied from lower G, considering G training effect for the subjects. Effects on performance decline and side effects of such a short-arm centrifugation were especially observed in the experiments, because this size of centrifuge could be used in space station in future for a strong countermeasure of cardiovascular deconditioning, demineralization from bone, etc. G training effect was observed same as higher and rapid G acceleration in fighter pilot. Subjects suffered from many types of discomfort; such as sensation of heaviness of diaphragm, cold sweat, nausea, irritable feeling, arrhythmia, tachycardia, rapid decrease of blood pressure, which sometimes caused interruption of G load. As 2.0 G and 60 minutes centrifugation seemed very tough load to the subjects, there should be necessary some G suit or other countermeasure, if we apply a higher G and/or longer G duration. Performance decline due to the load commonly continued for 1 hour or so. Side effects were observed in relation to neuro-vestibular, cardio-vascular, and autonomic nervous system.

  20. Low doses of nicotine-induced fetal cardiovascular responses, hypoxia, and brain cellular activation in ovine fetuses

    PubMed Central

    Guan, Junchang; Mao, Caiping; Xu, Feicao; Zhu, Liyan; Liu, Yujuan; Geng, Chongsong; Zhang, Lubo; Xu, Zhice

    2010-01-01

    Prenatal exposure to nicotine is associated with a variety of adverse outcomes. The present study investigated the effect of low doses of nicotine during pregnancy on fetal blood gases, cardiovascular system, and cellular activation in the brain. Intravenous administration of nicotine 10 or 25 μg/kg into ewe did not affect maternal blood gases, blood pressure, and heart rate. Maternal administration of nicotine also had no effect on fetal blood electrolyte concentrations, osmolality levels, and lactic acid levels. However, it significantly reduced fetal blood pO2 levels and oxygen saturation, increased fetal arterial blood pressure and decreased heart rate in utero. In addition, exposure to low doses of nicotine increased the expression of Fos in the paraventricular nucleus (PVN) and subfornic organ (SFO) in the fetal brain. The data demonstrated that even low doses of nicotine could impact significantly on fetal cardiovascular and central nervous systems, as well as oxygen status, and suggested a toxic risk to fetuses of exposure to low levels nicotine or second-hand smoking during pregnancy. PMID:19459226

  1. Gender differences and the relationships of perceived background stress and psychological distress with cardiovascular responses to laboratory stressors.

    PubMed

    Allen, Michael T; Bocek, Christine M; Burch, Ashley E

    2011-09-01

    The primary aim of this study was to evaluate the relationships of perceived background stress and self-reported psychological distress on cardiovascular reactivity during acute laboratory stressors. The Perceived Stress Scale (PSS) was used as the measure of perceived background stress, and the General Health Questionnaire (GHQ) was used as the measure of psychological distress. A secondary aim was to examine whether background stress and psychological distress affected the susceptibility to induction of a negative mood using music. Heart rate (HR) and blood pressure (BP) were measured in 149 female and male college students at rest and during a stressful mental arithmetic (MA) task and a mood induction procedure. Higher scores on the GHQ were associated with lower systolic BP reactivity during the MA task by all participants. Higher scores on the PSS and GHQ were also associated with lower diastolic BP and HR reactivity, but only in females. Thus, higher self-reports of background stress and psychological distress tended to result in blunted reactivity to an acute laboratory challenge. Higher levels of background stress and psychological distress were not associated with greater susceptibility to a negative mood induction. This study adds to the growing literature indicating that potentially negative health outcomes may be associated with diminished cardiovascular reactivity under certain conditions. PMID:21729723

  2. Role of nitric oxide-containing factors in the ventilatory and cardiovascular responses elicited by hypoxic challenge in isoflurane-anesthetized rats

    PubMed Central

    Mendoza, James P.; Passafaro, Rachael J.; Baby, Santhosh M.; Young, Alex P.; Bates, James N.; Gaston, Benjamin

    2014-01-01

    Exposure to hypoxia elicits changes in mean arterial blood pressure (MAP), heart rate, and frequency of breathing (fr). The objective of this study was to determine the role of nitric oxide (NO) in the cardiovascular and ventilatory responses elicited by brief exposures to hypoxia in isoflurane-anesthetized rats. The rats were instrumented to record MAP, heart rate, and fr and then exposed to 90 s episodes of hypoxia (10% O2, 90% N2) before and after injection of vehicle, the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME), or the inactive enantiomer d-NAME (both at 50 μmol/kg iv). Each episode of hypoxia elicited a decrease in MAP, bidirectional changes in heart rate (initial increase and then a decrease), and an increase in fr. These responses were similar before and after injection of vehicle or d-NAME. In contrast, the hypoxia-induced decreases in MAP were attenuated after administration of l-NAME. The initial increases in heart rate during hypoxia were amplified whereas the subsequent decreases in heart rate were attenuated in l-NAME-treated rats. Finally, the hypoxia-induced increases in fr were virtually identical before and after administration of l-NAME. These findings suggest that NO factors play a vital role in the expression of the cardiovascular but not the ventilatory responses elicited by brief episodes of hypoxia in isoflurane-anesthetized rats. Based on existing evidence that NO factors play a vital role in carotid body and central responses to hypoxia in conscious rats, our findings raise the novel possibility that isoflurane blunts this NO-dependent signaling. PMID:24744389

  3. Targeting brains, producing responsibilities: the use of neuroscience within British social policy.

    PubMed

    Broer, Tineke; Pickersgill, Martyn

    2015-05-01

    Concepts and findings 'translated' from neuroscientific research are finding their way into UK health and social policy discourse. Critical scholars have begun to analyse how policies tend to 'misuse' the neurosciences and, further, how these discourses produce unwarranted and individualizing effects, rooted in middle-class values and inducing guilt and anxiety. In this article, we extend such work while simultaneously departing from the normative assumptions implied in the concept of 'misuse'. Through a documentary analysis of UK policy reports focused on the early years, adolescence and older adults, we examine how these employ neuroscientific concepts and consequently (re)define responsibility. In the documents analysed, responsibility was produced in three different but intersecting ways: through a focus on optimisation, self-governance, and vulnerability. Our work thereby adds to social scientific examinations of neuroscience in society that show how neurobiological terms and concepts can be used to construct and support a particular imaginary of citizenship and the role of the state. Neuroscience may be leveraged by policy makers in ways that (potentially) reduce the target of their intervention to the soma, but do so in order to expand the outcome of the intervention to include the enhancement of society writ large. By attending as well to more critical engagements with neuroscience in policy documents, our analysis demonstrates the importance of being mindful of the limits to the deployment of a neurobiological idiom within policy settings. Accordingly, we contribute to increased empirical specificity concerning the impacts and translation of neuroscientific knowledge in contemporary society whilst refusing to take for granted the idea that the neurosciences necessarily have a dominant role (to play). PMID:25792340

  4. Human short-latency ocular vergence responses produced by interocular velocity differences.

    PubMed

    Sheliga, B M; Quaia, C; FitzGibbon, E J; Cumming, B G

    2016-08-01

    We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs. The IOVD cue was effective only when the images seen by the two eyes overlapped in space. We observed equally robust VRs for opposite horizontal motions (left in one eye, right in the other) and opposite vertical motions (up in one eye, down in the other). Whereas the former are naturally generated by objects moving in depth, the latter are not part of our normal experience. To our knowledge, this is the first demonstration of a behavioral consequence of vertical IOVD. This may reflect the fact that some neurons in area MT are sensitive to these motion signals (Czuba, Huk, Cormack, & Kohn, 2014). VRs were the strongest for spatial frequencies in the range of 0.35-1 c/°, much higher than the optimal spatial frequencies for evoking ocular-following responses observed during frontoparallel motion. This suggests that the two motion signals are detected by different neuronal populations. We also produced IOVD using moving uncorrelated one-dimensional white-noise stimuli. In this case the most effective stimuli have low speed, as predicted if the drive originates in neurons tuned to high spatial frequencies (Sheliga, Quaia, FitzGibbon, & Cumming, 2016). PMID:27548089

  5. Human short-latency ocular vergence responses produced by interocular velocity differences

    PubMed Central

    Sheliga, B. M.; Quaia, C.; FitzGibbon, E. J.; Cumming, B. G.

    2016-01-01

    We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs. The IOVD cue was effective only when the images seen by the two eyes overlapped in space. We observed equally robust VRs for opposite horizontal motions (left in one eye, right in the other) and opposite vertical motions (up in one eye, down in the other). Whereas the former are naturally generated by objects moving in depth, the latter are not part of our normal experience. To our knowledge, this is the first demonstration of a behavioral consequence of vertical IOVD. This may reflect the fact that some neurons in area MT are sensitive to these motion signals (Czuba, Huk, Cormack, & Kohn, 2014). VRs were the strongest for spatial frequencies in the range of 0.35–1 c/°, much higher than the optimal spatial frequencies for evoking ocular-following responses observed during frontoparallel motion. This suggests that the two motion signals are detected by different neuronal populations. We also produced IOVD using moving uncorrelated one-dimensional white-noise stimuli. In this case the most effective stimuli have low speed, as predicted if the drive originates in neurons tuned to high spatial frequencies (Sheliga, Quaia, FitzGibbon, & Cumming, 2016). PMID:27548089

  6. A long-term copper exposure on freshwater ecosystem using lotic mesocosms: Primary producer community responses.

    PubMed

    Roussel, Hélène; Ten-Hage, Loïc; Joachim, Sandrine; Le Cohu, René; Gauthier, Laury; Bonzom, Jean-Marc

    2007-02-28

    Copper is commonly used as an algicide and plant herbicide in the aquatic environment. Despite of its frequent application in rivers, ponds and lakes, few studies have been performed at the ecosystem level on primary producers' communities. A long-term lotic mesocosms study was carried on, in 20m long channels, under environmentally realistic concentrations of copper (0, 5, 25 and 75 microgL(-1)) delivered continuously for 18 months. Results showed significant effects at the 25 and 75 microgL(-1) copper treatment levels on the phytoplankton, periphyton and macrophyte community structure. Effects on biomass and abundance were dissimilar depending on the studied community. Phytoplankton showed no abundance variation with treatment, whereas periphyton had higher biomass and macrophytes had lower coverage at 25 and 75 microgL(-1). Taxa richness was significantly affected for all primary producers communities at 25 and 75 microgL(-1). Some taxa seemed to be sensitive to copper, i.e. Cocconeis spp., Epithemia sp., Gomphonema spp., Lemna minor, Nasturtium officinale and filamentous macroalgae. Other taxa appeared to be tolerant or facilitated by indirect effects, i.e. Leptolyngbya sp., Mougeotia sp., Nitzschia palea, Pseudanabaena sp. and Ulothrix sp. and therefore increased in the 25 and 75 microgL(-1) treatments. Important indirect factors influenced the community responses, such as trophic interactions like decrease of grazing pressure, competition for light and nutrients and temperature favouring blue-green algae development. After 18 months of copper exposure, the no observed effect concentration at community level (NOEC(community)) for primary producers was set up at 5 or 4mugL(-1), if we consider the average effective concentration, with a lowest observed effect concentration (LOEC(community)) at 25 or 20 microgL(-1) (AEC). PMID:17239970

  7. Indian poverty and cardiovascular disease.

    PubMed

    Ramaraj, Radhakrishnan; Alpert, Joseph Stephen

    2008-07-01

    Cardiovascular disease is among the world's leading causes of death, and nearly 80% of deaths occur in developing countries. Cardiovascular disease is becoming a major health problem in India, where life expectancy has increased with decreases in infectious disease and childhood mortality. It is well established that this population experiences coronary artery disease at a younger age than other populations. With infectious diseases still endemic, noncommunicable diseases are a lower priority for the governments of developing countries. There is a clear progression to degenerative and lifestyle-related diseases such as cardiovascular disease as a result of current social and economic change. The lack of a public response to the increasing risk for cardiovascular disease thus far is due mostly to a perception among policy makers and the public that cardiovascular disease is largely a problem of the urban rich. In conclusion, this review addresses the imminent threats and ways to tackle the epidemic in India. PMID:18572045

  8. Proteomic response of β-lactamases-producing Enterobacter cloacae complex strain to cefotaxime-induced stress.

    PubMed

    Maravić, Ana; Cvjetan, Svjetlana; Konta, Marina; Ladouce, Romain; Martín, Fernando A

    2016-07-01

    Bacteria of the Enterobacter cloacae complex are among the ten most common pathogens causing nosocomial infections in the USA. Consequently, increased resistance to β-lactam antibiotics, particularly expanded-spectrum cephalosporins like cefotaxime (CTX), poses a serious threat. Differential In-Gel Electrophoresis (DIGE), followed by LC-MS/MS analysis and bioinformatics tools, was employed to investigate the survival mechanisms of a multidrug-resistant E. hormaechei subsp. steigerwaltii 51 carrying several β-lactamase-encoding genes, including the 'pandemic' blaCTX-M-15 After exposing the strain with sub-minimal inhibitory concentration (MIC) of CTX, a total of 1072 spots from the whole-cell proteome were detected, out of which 35 were differentially expressed (P ≤ 0.05, fold change ≥1.5). Almost 50% of these proteins were involved in cell metabolism and energy production, and then cell wall organization/virulence, stress response and transport. This is the first study investigating the whole-cell proteomic response related to the survival of β-lactamases-producing strain, belonging to the E. cloacae complex when exposed to β-lactam antibiotic. Our data support the theory of a multifactorial synergistic effect of diverse proteomic changes occurring in bacterial cells during antibiotic exposure, depicting the complexity of β-lactam resistance and giving us an insight in the key pathways mediating the antibiotic resistance in this emerging opportunistic pathogen. PMID:27162211

  9. Sleep Restriction Increases the Risk of Developing Cardiovascular Diseases by Augmenting Proinflammatory Responses through IL-17 and CRP

    PubMed Central

    Karisola, Piia; Lindholm, Harri; Luukkonen, Ritva; Sallinen, Mikael; Härmä, Mikko; Porkka-Heiskanen, Tarja; Alenius, Harri

    2009-01-01

    Background Sleep restriction, leading to deprivation of sleep, is common in modern 24-h societies and is associated with the development of health problems including cardiovascular diseases. Our objective was to investigate the immunological effects of prolonged sleep restriction and subsequent recovery sleep, by simulating a working week and following recovery weekend in a laboratory environment. Methods and Findings After 2 baseline nights of 8 hours time in bed (TIB), 13 healthy young men had only 4 hours TIB per night for 5 nights, followed by 2 recovery nights with 8 hours TIB. 6 control subjects had 8 hours TIB per night throughout the experiment. Heart rate, blood pressure, salivary cortisol and serum C-reactive protein (CRP) were measured after the baseline (BL), sleep restriction (SR) and recovery (REC) period. Peripheral blood mononuclear cells (PBMC) were collected at these time points, counted and stimulated with PHA. Cell proliferation was analyzed by thymidine incorporation and cytokine production by ELISA and RT-PCR. CRP was increased after SR (145% of BL; p<0.05), and continued to increase after REC (231% of BL; p<0.05). Heart rate was increased after REC (108% of BL; p<0.05). The amount of circulating NK-cells decreased (65% of BL; p<0.005) and the amount of B-cells increased (121% of BL; p<0.005) after SR, but these cell numbers recovered almost completely during REC. Proliferation of stimulated PBMC increased after SR (233% of BL; p<0.05), accompanied by increased production of IL-1β (137% of BL; p<0.05), IL-6 (163% of BL; p<0.05) and IL-17 (138% of BL; p<0.05) at mRNA level. After REC, IL-17 was still increased at the protein level (119% of BL; p<0.05). Conclusions 5 nights of sleep restriction increased lymphocyte activation and the production of proinflammatory cytokines including IL-1β IL-6 and IL-17; they remained elevated after 2 nights of recovery sleep, accompanied by increased heart rate and serum CRP, 2 important risk factors for

  10. Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide.

    PubMed Central

    Stuehr, D J; Marletta, M A

    1985-01-01

    Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H/He and LPS-resistant C3H/HeJ mice. Intraperitoneal injection of 15 micrograms of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H/HeJ strain with LPS injections up to 175 micrograms. Furthermore, thioglycolate-elicited peritoneal macrophages from C3H/He, but not from C3H/HeJ mice, produced nitrite (60%) and nitrate (40%) when cultured with LPS (10 micrograms/ml). T-lymphocyte addition/depletion experiments showed the presence of T cells enhanced this response. However, LPS did not cause nitrite or nitrate production in cultures of spleen lymphocytes from either strain. LPS-induced nitrate synthesis was also observed with nude mice and CBA/N mice, indicating that neither functional T lymphocytes nor LPS-responsive B lymphocytes were required for the response in vivo. This was consistent with the in vitro results showing macrophages alone were competent. Mycobacterium bovis infection of C3H/He and C3H/HeJ mice resulted in a large increase in nitrate production over the course of the infection for both strains, suggesting T-lymphocyte-mediated activation of macrophages as a potent stimulus for nitrate biosynthesis. The synthesis of nitrite is significant in that it can directly participate in the endogenous formation of nitrosamines and may also be involved in some aspect of the chemistry of cytotoxicity. PMID:3906650

  11. Mammalian nitrate biosynthesis: mouse macrophages produce nitrite and nitrate in response to Escherichia coli lipopolysaccharide

    SciTech Connect

    Stuehr, D.J.; Marletta, M.A.

    1985-11-01

    Escherichia coli lipopolysaccharide (LPS)-induced nitrate biosynthesis was studied in LPS-sensitive C3H/He and LPS-resistant C3H/HeJ mice. Intraperitoneal injection of 15 ..mu..g of LPS led to a temporary 5- to 6-fold increase in blood nitrate concentration in the C3H/He strain. Levels of nitrate excreted in the urine were also increased. In contrast, no increase was observed in the C3H/HeJ strain with LPS injections up to 175 ..mu..g. Furthermore, thioglycolate-elicited peritoneal macrophages from C3H/He, but not from C3H/HeJ mice, produced nitrite (60%) and nitrate (40%) when cultured with LPS (10 ..mu..g/ml). T-lymphocyte addition/depletion experiments showed the presence of T cells enhanced this response. However, LPS did not cause nitrite or nitrate production in cultures of spleen lymphocytes from either strain. LPS-induced nitrate synthesis was also observed with nude mice and CBA/N mice, indicating that neither functional T lymphocytes nor LPS-responsive B lymphocytes were required for the response in vivo. This was consistent with the in vitro results showing macrophages alone were competent. Mycobacterium bovis infection of C3H/He and C3H/HeJ mice resulted in a large increase in nitrate production over the course of the infection for both strains, suggesting T-lymphocyte-mediated activation of macrophages as a potent stimulus for nitrate biosynthesis. The synthesis of nitrite is significant in that it can directly participate in the endogenous formation of nitrosamines and may also be involved in some aspect of the chemistry of cytotoxicity.

  12. Individual Differences in the Temporal Profile of Cardiovascular Responses to Head Down Tilt and Orthostatic Stress with and Without Fluid Loading

    NASA Technical Reports Server (NTRS)

    Cowings, Patricia; Toscano, William; Kanis, Dionisios; Gebreyesus, Fiyore

    2013-01-01

    Susceptibility of healthy astronauts to orthostatic hypotension and presyncope is exacerbated upon return from spaceflight. Hypo-volemia is suspected to play an important role in cardiovascular deconditioning following exposure to spaceflight, which may lead to increased peripheral resistance, attenuated arterial baroreflex, and changes in cardiac function. The effect of altered gravity during space flight and planetary transition on human cardiovascular function is of critical importance to maintenance of astronaut health and safety. A promising countermeasure for post-flight orthostatic intolerance is fluid loading used to restore loss fluid volume by giving crew salt tablets and water prior to re-entry. Eight men and eight women will be tested during two, 6-hour exposures to 6o HDT: 1) fluid loading, 2) no fluid loading. Before and immediately after each HDT, subjects will perform a stand test to assess their orthostatic tolerance. Physiological measures (e.g., ECG, blood pressure, peripheral blood volume) will be continuously monitored while echocardiography measures are recorded at 30-minute intervals during HDT and stand tests. Preliminary results (N=4) clearly show individual differences in responses to this countermeasure and the time course of physiological changes induced by HDT.

  13. Comparison of cardiovascular response to sinusoidal and constant lower body negative pressure with reference to very mild whole-body heating

    PubMed Central

    2012-01-01

    Background The purpose of the present study was to compare sinusoidal versus constant lower body negative pressure (LBNP) with reference to very mild whole-body heating. Sinusoidal LBNP has a periodic load component (PLC) and a constant load component (CLC) of orthostatic stress, whereas constant LBNP has only a CLC. We tested two sinusoidal patterns (30-s and 180-s periods with 25 mmHg amplitude) of LBNP and a constant LBNP with −25 mmHg in 12 adult male subjects. Results Although the CLC of all three LBNP conditions were configured with −25 mmHg, the mean arterial pressure (MAP) results showed a significantly large decrease from baseline in the 30-s period condition (P <0.01). In contrast, the other cardiovascular indices (heart rate (HR), stroke volume (SV), cardiac output (CO), basal thoracic impedance (Z0), total peripheral resistance (TPR), the natural logarithmic of the HF component (lnHF), and LF/HF (ln(LF/HF))) of heart rate variability (HRV) showed relatively small variations from baseline in the 30-s period condition (P <0.01). The result of the gain and phase of transfer function at the sinusoidal period of LBNP showed that the very mild whole-body heating augmented the orthostatic responses. Conclusion These results revealed that the effect of the CLC of LBNP on cardiovascular adjustability was attenuated by the addition of the PLC to LBNP. Based on the results of suppressed HRV response from baseline in the 30-s period condition, we suggest that the attenuation may be caused by the suppression of the vagal responsiveness to LBNP. PMID:23176638

  14. Changes in and Stability of Cardiovascular Responses to Behavorial Stress: Results from a Four-Year Longitudinal Study of Children.

    ERIC Educational Resources Information Center

    Matthews, Karen A.; And Others

    1990-01-01

    Blood pressure and heart rate responses during serial subtraction, mirror image tracing, and isometric exercise tasks were longitudinally reliable for all measures except heart rate responses during isometric exercise. Systolic blood pressure responses to all tasks increased with age for boys, but not for girls. (RH)

  15. Dufulin Activates HrBP1 to Produce Antiviral Responses in Tobacco

    PubMed Central

    Chen, Zhuo; Zeng, Mengjiao; Song, Baoan; Hou, Chengrui; Hu, Deyu; Li, Xiangyang; Wang, Zhenchao; Fan, Huitao; Bi, Liang; Liu, Jiaju; Yu, Dandan; Jin, Linhong; Yang, Song

    2012-01-01

    Background Dufulin is a new antiviral agent that is highly effective against plant viruses and acts by activating systemic acquired resistance (SAR) in plants. In recent years, it has been used widely to prevent and control tobacco and rice viral diseases in China. However, its targets and mechanism of action are still poorly understood. Methodology/Principal Findings Here, differential in-gel electrophoresis (DIGE) and classical two-dimensional electrophoresis (2-DE) techniques were combined with mass spectrometry (MS) to identify the target of Dufulin. More than 40 proteins were found to be differentially expressed (≥1.5 fold or ≤1.5 fold) upon Dufulin treatment in Nicotiana tabacum K326. Based on annotations in the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, these proteins were found to be related to disease resistance. Directed acyclic graph (DAG) analysis of the various pathways demonstrated harpin binding protein-1 (HrBP1) as the target of action of Dufulin. Additionally, western blotting, semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), and real time PCR analyses were also conducted to identify the specific mechanism of action of Dufulin. Our results show that activation of HrBP1 triggers the salicylic acid (SA) signaling pathway and thereby produces antiviral responses in the plant host. A protective assay based on lesion counting further confirmed the antiviral activity of Dufulin. Conclusion This study identified HrBP1 as a target protein of Dufulin and that Dufulin can activate the SA signaling pathway to induce host plants to generate antiviral responses. PMID:22662252

  16. T cell senescence and cardiovascular diseases.

    PubMed

    Yu, Hee Tae; Park, Sungha; Shin, Eui-Cheol; Lee, Won-Woo

    2016-08-01

    Age-related changes in the immune system, commonly termed "immunosenescence," contribute to deterioration of the immune response and fundamentally impact the health and survival of elderly individuals. Immunosenescence affects both the innate and adaptive immune systems; however, the most notable changes are in T cell immunity and include thymic involution, the collapse of T cell receptor (TCR) diversity, an imbalance in T cell populations, and the clonal expansion of senescent T cells. Senescent T cells have the ability to produce large quantities of proinflammatory cytokines and cytotoxic mediators; thus, they have been implicated in the pathogenesis of many chronic inflammatory diseases. Recently, an increasing body of evidence has suggested that senescent T cells also have pathogenic potential in cardiovascular diseases, such as hypertension, atherosclerosis, and myocardial infarction, underscoring the detrimental roles of these cells in various chronic inflammatory responses. Given that cardiovascular disease is the number one cause of death worldwide, there is great interest in understanding the contribution of age-related immunological changes to its pathogenesis. In this review, we discuss general features of age-related alterations in T cell immunity and the possible roles of senescent T cells in the pathogenesis of cardiovascular disease. PMID:26188489

  17. Undergraduates' understanding of cardiovascular phenomena.

    PubMed

    Michael, Joel A; Wenderoth, Mary Pat; Modell, Harold I; Cliff, William; Horwitz, Barbara; McHale, Philip; Richardson, Daniel; Silverthorn, Dee; Williams, Stephen; Whitescarver, Shirley

    2002-12-01

    Undergraduates students in 12 courses at 8 different institutions were surveyed to determine the prevalence of 13 different misconceptions (conceptual difficulties) about cardiovascular function. The prevalence of these misconceptions ranged from 20 to 81% and, for each misconception, was consistent across the different student populations. We also obtained explanations for the students' answers either as free responses or with follow-up multiple-choice questions. These results suggest that students have a number of underlying conceptual difficulties about cardiovascular phenomena. One possible source of some misconceptions is the students' inability to apply simple general models to specific cardiovascular phenomena. Some implications of these results for teachers of physiology are discussed. PMID:12031940

  18. Cardiovascular and nervous system changes during meditation

    PubMed Central

    Steinhubl, Steven R.; Wineinger, Nathan E.; Patel, Sheila; Boeldt, Debra L.; Mackellar, Geoffrey; Porter, Valencia; Redmond, Jacob T.; Muse, Evan D.; Nicholson, Laura; Chopra, Deepak; Topol, Eric J.

    2015-01-01

    Background: A number of benefits have been described for the long-term practice of meditation, yet little is known regarding the immediate neurological and cardiovascular responses to meditation. Wireless sensor technology allows, for the first time, multi-parameter and quantitative monitoring of an individual's responses during meditation. The present study examined inter-individual variations to meditation through continuous monitoring of EEG, blood pressure, heart rate and its variability (HRV) in novice and experienced meditators. Methods: Participants were 20 experienced and 20 novice meditators involved in a week-long wellness retreat. Monitoring took place during meditation sessions on the first and last full days of the retreat. All participants wore a patch that continuously streamed ECG data, while half of them also wore a wireless EEG headset plus a non-invasive continuous blood pressure monitor. Results: Meditation produced variable but characteristic EEG changes, significantly different from baseline, even among novice meditators on the first day. In addition, although participants were predominately normotensive, the mean arterial blood pressure fell a small (2–3 mmHg) but significant (p < 0.0001) amount during meditation. The effect of meditation on HRV was less clear and influenced by calculation technique and respiration. No clear relationship between EEG changes, HRV alterations, or mean blood pressure during meditation was found. Conclusion: This is the first study to investigate neurological and cardiovascular responses during meditation in both novice and experienced meditators using novel, wearable, wireless devices. Meditation produced varied inter-individual physiologic responses. These results support the need for further investigation of the short- and long-term cardiovascular effects of mental calm and individualized ways to achieve it. PMID:25852526

  19. The immune response of juvenile Atlantic cod (Gadus morhua L.) to chronic exposure to produced water.

    PubMed

    Pérez-Casanova, Juan C; Hamoutene, Dounia; Samuelson, Stephanie; Burt, Kimberly; King, Thomas L; Lee, Kenneth

    2010-07-01

    Produced water (PW) is the main discharge from the offshore oil industry and contains oil-derived compounds such as poly-aromatic hydrocarbons, phenols, alkylphenols, and heavy metals. Studies suggest that PW discharges may affect the biota over larger areas from the oil drilling sites at sea than originally predicted. We investigated the effects of chronic exposure to PW on some aspects of juvenile Atlantic cod immunity, stress response and growth by intermittently exposing fish to 0, 100 or 200 ppm of PW for 22 weeks. No significant effects of PW were observed on growth, hepatosomatic index, condition factor or plasma cortisol. The respiratory burst (RB) of circulating leukocytes was significantly elevated in the 100 ppm group only, while the RB of head-kidney leukocytes was significantly decreased in both the 100 and 200 ppm groups. Significant up-regulation of the mRNA expression of beta-2-microglobulin, immunoglobulin-M light chain and interleukins-1beta and -8 was observed in the 200 ppm group, while the down-regulation of interferon stimulated gene 15 was obvious for both the 100 and 200 ppm groups. The results suggest that chronic exposure to environmentally relevant concentrations of PW causes modulations of the immune system of juvenile Atlantic cod with most immune parameters being stimulated, potentially resulting in an energetic cost that may be detrimental to the fish. PMID:20338632

  20. Cardiovascular responses to noise: Effects of self-estimated sensitivity to noise, sex, and time of the day

    NASA Astrophysics Data System (ADS)

    di Nisi, J.; Muzet, A.; Weber, L. D.

    1987-04-01

    Eighty subjects of both sexes were selected according to their self-estimated high or low sensitivity to noise. Noise exposure took place during a mental task ("sound" condition) or during a video film illustrating the noises ("sound and video" condition). The experiments were conducted between 0900 and 1100 hours or between 1500 and 1700 hours. Heart rate response and finger pulse response amplitudes were averaged separately for "sound" and "sound and video" conditions. In the "sound" condition, the average amplitude of the heart rate response differed significantly between noise-sensitivity groups: the low sensitivity group showed a lower average amplitude of heart rate response than the high sensitivity group. A significant interaction between sex and time of the day (morning or afternoon) was observed in both "sound" and "sound and video" conditions. In the "sound" condition, the percentage of noises inducing a finger pulse response appeared higher in female than in male subjects.

  1. The effects of genes implicated in cardiovascular disease on blood pressure response to treatment among treatment-naive hypertensive African Americans in the GenHAT study.

    PubMed

    Do, A N; Lynch, A I; Claas, S A; Boerwinkle, E; Davis, B R; Ford, C E; Eckfeldt, J H; Tiwari, H K; Arnett, D K; Irvin, M R

    2016-09-01

    African Americans have the highest prevalence of hypertension in the United States. Blood pressure (BP) control is important to reduce cardiovascular disease-related morbidity and mortality in this ethnic group. Genetic variants have been found to be associated with BP response to treatment. Previous pharmacogenetic studies of BP response to treatment in African Americans suffer limitations of small sample size as well as a limited number of candidate genes, and often focused on one antihypertensive treatment. Using 1131 African-American treatment-naive participants from the Genetics of Hypertension Associated Treatment Study, we examined whether variants in 35 candidate genes might modulate BP response to four different antihypertensive medications, including an angiotensin-converting enzyme inhibitor (lisinopril), a calcium channel blocker (amlodipine), and an a-adrenergic blocker (doxazosin) as compared with a thiazide diuretic (chlorthalidone) after 6 months of follow-up. Several suggestive gene by treatment interactions were identified. For example, among participants with two minor alleles of renin rs6681776, diastolic BP response was much improved on doxazosin compared with chlorthalidone (on average -9.49 mm Hg vs -1.70 mm Hg) (P=0.007). Although several suggestive loci were identified, none of the findings passed significance criteria after correction for multiple testing. Given the impact of hypertension and its sequelae in this population, this research highlights the potential for genetic factors to contribute to BP response to treatment. Continued concerted research efforts focused on genetics are needed to improve treatment response in this high-risk group. PMID:26791477

  2. The Basic Cardiovascular Responses to Postural Changes, Exercise, and Cold Pressor Test: Do They Vary in Accordance with the Dual Constitutional Types of Ayurveda?

    PubMed Central

    Tripathi, Piyush Kumar; Patwardhan, Kishor; Singh, Girish

    2011-01-01

    According to Ayurveda, the native Indian system of healthcare, three Doshas, namely, Vata, Pitta, and Kapha, are the basic mutually reciprocal mechanisms that are responsible for the maintenance of homeostasis in human beings. Ayurveda classifies entire human population into seven constitutional types (Prakriti), based on the dominance of any single or a combination of two or three Doshas. Considering the fact that, in the recent past there have been several studies that have proposed some important genetic, biochemical and haematological bases for Prakriti, we conducted the present study in 90 randomly selected clinically healthy volunteers belonging to dual constitutional types (Dvandvaja Prakriti) to evaluate the variability of heart rate and arterial blood pressure in response to specific postural changes, exercise, and cold pressor test. The results of this study, in general, suggest that these basic cardiovascular responses do not vary significantly as per the dual constitutional types. However, we noted a significant fall in the diastolic blood pressure immediately after performing the isotonic exercise for five minutes, in Vata-Kapha individuals in comparison to the other two groups, namely, Pitta-Kapha and Vata-Pitta. PMID:20953421

  3. The response of primary producers to nutrient enrichment in a shallow estuary

    USGS Publications Warehouse

    Kinney, E.H.; Roman, C.T.

    1998-01-01

    Shallow coastal systems worldwide are exhibiting increased algal growth in response to nutrient enrichment. This study evaluates primary production patterns in an estuarine system (Bass Harbor Marsh, Maine) receiving low levels of anthropogenic nitrogen. Biomass, areal coverage and in situ oxygen production of green macroalgae, Ruppia maritima, and phytoplankton were measured over a growing season to determine net ecosystem production. Macroalgae and Ruppia exhibited strong seasonal biomass curves with early summer peaks; however, peak biomass of macroalgae (150 g dwt m-2) was substantially greater than Ruppia (33 g dwt m-2). Phytoplankton biomass, measured as chlorophyll a, was low (<1 ug l-1) early in the season and peaked (11 ug l-1) following a mid-summer decline in macroalgal biomass, suggesting a competitive interaction with macroalgae. Instantaneous net production rates varied over the growing season for all three primary producers. Ruppia net production ranged from near zero to 3.7 mg C g dwt-1 h-1, with higher rates during summer and much of the seasonal variability explained by temperature. Macroalgal (0.88 - 5.0 mg C g dwt-1 h-1) and phytoplankton (0 - 28 mg C m-3 h-1) net production did not exhibit any clear seasonal signal. Net primary production calculated on an areal basis demonstrated macroalgae's dominance in the lower basin of Bass Harbor Marsh, with peak summer rates (400 mg C m-2 h-1) greatly exceeding maximum rates for both Ruppia (70 mg C m-2 h-1) and phytoplankton (12 mg C m-2 h-1). When compared to other New England estuarine sites with short residence times, nutrient loading and peak green macroalgal biomass in Bass Harbor Marsh is relatively low; however, the strong dominance of opportunistic green macroalgae is a pattern that is characteristic of shallow coastal systems undergoing eutrophication.

  4. Light limitation in a stream ecosystem: Responses by primary producers and consumers

    SciTech Connect

    Hill, W.R.; Ryon, M.G.; Schilling, E.M.

    1995-06-01

    Heavy shade presents serious challenges for primary producers and food-limited herbivores in forest streams. This study examines the response of periphyton and grazing snails (Elimia clavaeformis) to summer shade in White Oak Creek (WOC) in a Tennessee deciduous forest. Three experiments were performed: (1) in situ manipulation of light and snail density to test the effects of light limitation and grazing; (2) construction of photosynthesis-irradiance (P-I) curves to test for shade adaptation by periphyton; and (3) measurements of snail growth vs. irradiance. In the first experiment, light and snail densities were manipulated in a 2 x 2 factorial design. Snails at normal densities cropped periphyton biomass to low levels regardless of light regime, but periphyton productivity was higher at the open sites where snails grew faster and accumulated more lipid. Snail growth and lipid accumulation were strongly affected by intraspecific competition in both light regimes. In the second experiment, photosynthesis-irradiance curves for periphyton from shaded and open sites illustrated considerable shade adaptation: shaded periphyton was 2 times more efficient at low irradiance than with periphyton from open sites. Despite the greater efficiency of shaded periphyton at low irradiance, integrated primary production estimated with photosynthetic models was 4 times greater in the open because shade adaptation provided only partial compensation for the shade. In the third experiment, in situ snail growth again increased with decreasing shade. Bottom-up effects of light limitation were propagated very strongly in WOC, where the vertebrate fauna is dominated by a grazer that appears to escape top-down control. 68 refs., 4 figs., 3 tabs.

  5. Responses of organic and inorganic materials to intense EUV radiation from laser-produced plasmas

    NASA Astrophysics Data System (ADS)

    Makimura, Tetsuya; Torii, Shuichi; Nakamura, Daisuke; Takahashi, Akihiko; Okada, Tatsuo; Niino, Hiroyuki; Murakami, Kouichi

    2013-05-01

    We have investigated responses of polymers to EUV radiation from laser-produced plasmas beyond ablation thresholds and micromachining. We concentrated on fabricate precise 3D micro-structures of PDMS, PMMA, acrylic block copolymers (BCP), and silica. The micromachining technique can be applied to three-dimensional micro-fluidic and bio-medical devices. The EUV processing is a promising to realize a practical micromachining technique. In the present work, we used two EUV radiation sources; (a) Wide band EUV light in a range of 10{300 eV was generated by irradiation of Ta targets with Nd:YAG laser light at 500 mJ/pulse. (b) Narrow band EUV light at 11 and 13 nm was generated by irradiation of solid Xe and Sn targets, respectively, with pulsed TEA CO2 laser light. The generated EUV light was condensed onto the materials at high power density beyond the ablation thresholds, using ellipsoidal mirrors. We found that through-holes with a diameter of one micrometer an be fabricated in PMMA and PDMS sheets with thicknesses of 4-10 micrometers, at 250 and 230 nm/shot, respectively. The effective ablation of PMMA sheets can be applied to a LIGA-like process for fabricating micro-structures of metals for micro- and nano-molds. PDMS sheets are ablated if it is irradiated with EUV light beyond a distinct threshold power density, while PDMS surfaces were modified at lower power densities. Furthermore, BCP sheets were ablated to have 1-micrometer structures. Thus, we have developed a practical technique for micromachining of PMMA, PDMS and BCP sheets in a micrometer scale.

  6. Response of primary producers to nutrient enrichment in a shallow estuary

    USGS Publications Warehouse

    Kinney, E.H.; Roman, C.T.

    1998-01-01

    Shallow coastal systems worldwide are exhibiting increased algal growth in response to nutrient enrichment. This study evaluates primary production patterns in an estuarine system (Bass Harbor Marsh, ME, USA) receiving low levels of anthropogenic nitrogen. Biomass, areal coverage and in situ oxygen production of green macroalgae, Ruppia Maritima, and Phytoplankton were measured over a growing season to determine net ecosystem production. Macroalgae and R. maritima exhibited seasonal biomass curves with early summer peaks; however, peak biomass of macroalgae [150 g dry weight (wt) m-2] was substantially greater that R. maritima (33 g dry wt m-2) Phytoplankton biomass, measured as chlorophyll a, was low (<1 ??g 1-1) early in the season and peaked (11 ??g 1-1) following a mid-summer decline in macroalgal biomass, suggesting a competitive interaction with macroalgae. Instantaneous net production rates varied over the growing season for all 3 primary producers. R. maritima net production ranged from near zero to 2.7 mg C g-1 dry wt h-1, with higher rates during summer and much of the seasonal variability explained by temperature. Macroalgal (0.88 to 5.0 mg C g-1 dry wt h-1) and phytoplankton (0 to 28 mg C m-3 h-1) net production did not exhibit any clear seasonal signal. Net primary production calculated on an areal basis demonstrated macroalgae's dominance in the lower basin of Bass Harbor Marsh, with peak summer rates (400 mg C m-2 h-1) greatly exceeding maximum rates for both R maritima (70 mg C m-2h-1) and phytoplankton (12 mg C m-2 h-1). When compared to other New England estuarine sites with short residence times, nutrient loading and peak green macroalgal biomass in Bass Harbor Marsh are relatively low; however, the strong dominance of opportunistic green macroalgae is a pattern that is characteristic of shallow coastal systems undergoing eutrophication.

  7. Cardiovascular adaptation to spaceflight

    NASA Technical Reports Server (NTRS)

    Hargens, A. R.; Watenpaugh, D. E.

    1996-01-01

    This article reviews recent flight and ground-based studies of cardiovascular adaptation to spaceflight. Prominent features of microgravity exposure include loss of gravitational pressures, relatively low venous pressures, headward fluid shifts, plasma volume loss, and postflight orthostatic intolerance and reduced exercise capacity. Many of these short-term responses to microgravity extend themselves during long-duration microgravity exposure and may be explained by altered pressures (blood and tissue) and fluid balance in local tissues nourished by the cardiovascular system. In this regard, it is particularly noteworthy that tissues of the lower body (e.g., foot) are well adapted to local hypertension on Earth, whereas tissues of the upper body (e.g., head) are not as well adapted to increase in local blood pressure. For these and other reasons, countermeasures for long-duration flight should include reestablishment of higher, Earth-like blood pressures in the lower body.

  8. Field Dependence and Social Responsiveness as Determinants of Spontaneously Produced Words.

    ERIC Educational Resources Information Center

    Goldberger, Leo; Bendich, Stephen

    This study measured responsiveness to the immediate environment on the basis of the social (vs. neutral) content of a person's free associations, in an effort to relate this responsiveness to field-dependence. The results lend support to the view that field-dependence is associated with social responsiveness in word association. Two aspects of…

  9. Cardiovascular group

    NASA Technical Reports Server (NTRS)

    Blomqvist, Gunnar

    1989-01-01

    As a starting point, the group defined a primary goal of maintaining in flight a level of systemic oxygen transport capacity comparable to each individual's preflight upright baseline. The goal of maintaining capacity at preflight levels would seem to be a reasonable objective for several different reasons, including the maintenance of good health in general and the preservation of sufficient cardiovascular reserve capacity to meet operational demands. It is also important not to introduce confounding variables in whatever other physiological studies are being performed. A change in the level of fitness is likely to be a significant confounding variable in the study of many organ systems. The principal component of the in-flight cardiovascular exercise program should be large-muscle activity such as treadmill exercise. It is desirable that at least one session per week be monitored to assure maintenance of proper functional levels and to provide guidance for any adjustments of the exercise prescription. Appropriate measurements include evaluation of the heart-rate/workload or the heart-rate/oxygen-uptake relationship. Respiratory gas analysis is helpful by providing better opportunities to document relative workload levels from analysis of the interrelationships among VO2, VCO2, and ventilation. The committee felt that there is no clear evidence that any particular in-flight exercise regimen is protective against orthostatic hypotension during the early readaptation phase. Some group members suggested that maintenance of the lower body muscle mass and muscle tone may be helpful. There is also evidence that late in-flight interventions to reexpand blood volume to preflight levels are helpful in preventing or minimizing postflight orthostatic hypotension.

  10. Correlation of M235T DNA polymorphism with cardiovascular and endocrine responses during physical exercise in healthy subjects.

    PubMed

    Krizanová, O; Koska, J; Vigas, M; Kvetnanský, R

    1998-01-01

    In our experiments, we evaluated the possible effect of M235T molecular variant of the angiotensinogen gene on the response to a physical workload. A group of volunteers was composed of healthy male subjects, approximately of the same weight and height, same age and not actively trained. None of these subjects was under any medication. Blood sampling was carried out via an indwelling catheter. Besides blood pressure and heart rate, angiotensin I, angiotensin II, epinephrine and norepinephrine concentrations were measured in the blood. Our results suggest that only the response of diastolic blood pressure during submaximal exercise corresponded to the presence of M235T molecular variant. In all other parameters we found no significant correlation of the response with the M235T molecular variant. PMID:9706989

  11. Comparison of host response mechanisms evoked by extended spectrum beta lactamase (ESBL)- and non-ESBL-producing uropathogenic E. coli

    PubMed Central

    2013-01-01

    Background Infections caused by extended spectrum beta-lactamases (ESBL)-producing bacteria have been emerging worldwide and the majority of ESBL-producing E. coli strains are isolated from patients with urinary tracts infections. The purpose of this study was to compare the host-response mechanisms in human polymorphonucleated leukocytes (PMN) and renal epithelial cells when stimulated by ESBL- or non-ESBL-producing uropathogenic E. coli (UPEC) isolates. The host-pathogen interaction of these ESBL-producing strains in the urinary tract is not well studied. Results The ability of ESBL strains to evoke ROS-production from PMN cells was significantly higher than that of the non-ESBL strains. The growth of ESBL strains was slightly suppressed in the presence of PMN compared to non-ESBL strains after 30 min and 2 h, but the opposite was observed after 5 and 6 h. The number of migrating PMN was significantly higher in response to ESBL strains compared to non-ESBL strains. Stimulation of A498 cells with ESBL strains elicited lower production of IL-6 and IL-8 compared to non-ESBL strains. Conclusion Significant differences in host-response mechanisms were identified when host cells were stimulated by ESBL- or non-ESBL producing strains. The obtained results on the early interactions of ESBL-producing strains with the host immune system may provide valuable information for management of these infections. PMID:24059789

  12. Emotional and Cardiovascular Responses to Adults' Angry Behavior and to Challenging Tasks in Children of Hypertensive and Normotensive Parents.

    ERIC Educational Resources Information Center

    Ballard, Mary E.; And Others

    1993-01-01

    Found that, although 10- to 14-year-old sons of hypertensive parents showed greater systolic blood pressure reactivity to interadult anger and to a challenging task than sons of normotensive parents, there was no consistent pattern in the response of girls. (MDM)

  13. Brain mediators of cardiovascular responses to social threat, Part II: Prefrontal-subcortical pathways and relationship with anxiety

    PubMed Central

    Wager, Tor D.; van Ast, Vanessa A.; Hughes, Brent L.; Davidson, Matthew L.; Lindquist, Martin A.; Ochsner, Kevin N.

    2009-01-01

    Social evaluative threat (SET) is a potent stressor in humans linked to autonomic and endocrine responses, and multiple health problems. Neuroimaging has recently begun to elucidate the brain correlates of SET, but as yet little is known about the mediating cortical-brainstem pathways in humans. This paper replicates and extends findings in a companion paper (Wager et al., submitted) using an independent cohort of participants and different image acquisition parameters. Here, we focused specifically on relationships between the medial prefrontal cortex (MPFC), midbrain periaqueductal gray (PAG), and heart rate (HR). We applied multi-level path analysis to localize brain mediators of SET effects on HR and self-reported anxiety. HR responses were mediated by opposing signals in two distinct sub-regions of the MPFC—increases in rostral dorsal anterior cingulate cortex (rdACC) and deactivation in ventromedial prefrontal cortex (vmPFC). In addition, HR responses were mediated by PAG. Additional path analyses provided support for two cortical subcortical pathways: one linking vmPFC, PAG, and HR, and another linking rdACC, thalamus, and HR. PAG responses were linked with HR changes both before and during SET, whereas cortical regions showed stronger connectivity with HR during threat. Self-reported anxiety showed a partially overlapping, but weaker, pattern of mediators, including the vmPFC, dorsomedial PFC (dmPFC), and lateral frontal cortex, as well as substantial individual differences that were largely unexplained. Taken together, these data suggest pathways for the translation of social threats into both physiological and experiential responses, and provide targets for future research on the generation and regulation of emotion. PMID:19465135

  14. 33 CFR 135.403 - Sanctions for failure to produce vessel Certificates of Financial Responsibility.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE POLLUTION FINANCIAL RESPONSIBILITY AND COMPENSATION OFFSHORE OIL POLLUTION COMPENSATION FUND Access, Denial, and Detention § 135.403 Sanctions...

  15. Intracellular proteins produced by mammalian cells in response to environmental stress

    NASA Technical Reports Server (NTRS)

    Goochee, Charles F.; Passini, Cheryl A.

    1988-01-01

    The nature of the response of mammalian cells to environmental stress is examined by reviewing results of studies where cultured mouse L cells and baby hamster kidney cells were exposed to heat shock and the synthesis of heat-shock proteins and stress-response proteins (including HSP70, HSC70, HSP90, ubiquitin, and GRP70) in stressed and unstressed cells was evaluated using 2D-PAGE. The intracellular roles of the individual stress response proteins are discussed together with the regulation of the stress response system.

  16. Cardiovascular and Affective Outcomes of Active Gaming: Using the Nintendo Wii as a Cardiovascular Training Tool

    PubMed Central

    Naugle, Keith E.; Naugle, Kelly M.; Wikstrom, Erik A.

    2014-01-01

    Naugle, KE, Naugle, KM, and Wikstrom, EA. Cardiovascular and affective outcomes of active gaming: Using the Nintendo Wii as a cardiovascular training tool. J Strength Cond Res 28(2): 443–451, 2014–Active-video gaming is purported to produce similar cardiovascular responses as aerobic fitness activities. This study compared the emotional and cardiovascular effects of Wii games with those of traditional exercise in college-aged adults with different exercise backgrounds. Specifically, the percentage of heart rate reserve, rate of perceived exertion (RPE), level of enjoyment, and Positive and Negative Affect Schedule scores were compared between subjects who reported exercising frequently at high intensities (high-intensity exerciser group: age = 20.18 years [0.87]; Height = 165.23 cm [9.97]; Mass = 62.37 kg [11.61]), N = 11 and those who exercise more often at lower intensities (low-intensity exercisers group: age = 20.72 years [1.19]; Height = 164.39 cm [8.05]; Mass = 68.04 kg [10.71]), N = 11. The subjects completed six 20-minute exercises sessions: treadmill walking, stationary cycling, and Wii's Tennis, Boxing, Cycling, and Step. The low-intensity exerciser group achieved a greater percentage of heart rate reserve (a) during traditional exercise compared with that during Wii boxing, (b) playing Wii boxing compared with that for Wii tennis, and (c) playing Wii boxing compared with that when the high-intensity exercisers group played any Wii games (p < 0.05). The RPE was greater for boxing and cycling compared with that for tennis and step (p < 0.05). Ratings of enjoyment and the increase in positive emotion were greater for boxing and for tennis compared with those for traditional exercises (p < 0.05). Results suggest that Wii boxing shows the greatest potential as a cardiovascular fitness tool among the Wii games, particularly for individuals who typically exercise at lower intensities. PMID:23660574

  17. [Cardiovascular manifestations of human toxocariasis].

    PubMed

    Bolívar-Mejía, Adrián; Rodríguez-Morales, Alfonso J; Paniz-Mondolfi, Alberto E; Delgado, Olinda

    2013-01-01

    Toxocariasis is a parasitic infection produced by helminths that cannot reach their adult stage in humans. For their etiological species (Toxocara canis and Toxocara cati), man is a paratenic host. Infection by such helminths can produce a variety of clinical manifestations, such as: visceral larvae migrans syndrome, ocular larvae migrans syndrome and covert toxocariasis. In the visceral larvae migrans syndrome, the organs that are mainly involved include liver, lungs, skin, nervous system, muscles, kidneys and the heart. Regarding the latter, the importance of cardiovascular manifestations in toxocariasis, as well as its clinical relevance, has increasingly begun to be recognized. The current article is based on a systematic information search, focused mainly on the clinical and pathological aspects of cardiovascular manifestations in toxocariasis, including its pathophysiology, laboratory findings, diagnosis and therapeutical options, with the objective of highlighting its importance as a zoonosis and its relevance to the fields of cardiovascular medicine in adults and children. PMID:23462238

  18. CARDIOVASCULAR EFFECTS OF ULTRAFINE CARBON PARTICLES IN HYPERTENSIVE RATS (SHR)

    EPA Science Inventory

    Rationale: Epidemiological evidence suggests that ultrafine particles are associated with adverse cardiovascular effects, specifically in elderly individuals with preexisting cardiovascular disease. The objective of this study was (i) to assess cardiopulmonary responses in adult ...

  19. S-Nitrosothiols-NO donors regulating cardiovascular cell proliferation: Insight into intracellular pathway alterations.

    PubMed

    Rychter, Marek; Gaucher, Caroline; Boudier, Ariane; Leroy, Pierre; Lulek, Janina

    2016-09-01

    Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) activates signaling pathways responsible for smooth muscle cell relaxation, leading to vasodilation and thus plays an important role in controlling vascular homeostasis, thrombosis and inflammation. Recent studies indicate that S-nitrosothiols produced in vivo as well as synthetic ones might be important reservoirs of NO. Based on a broad range of NO functions within the living organisms, this review highlights the impact of S-nitrosothiols on cardiovascular cell cycle. The cell membrane transport and the decomposition patterns responsible of S-nitrosothiols actions are presented. The effects of NO delivery through S-nitrosothiols have a significant potential in cardiovascular diseases with various underlying causes. The challenges related to their application in the pharmacotherapy of patients with various cardiovascular diseases are also discussed. PMID:27394657

  20. Policy options to reduce consumer waste to zero: comparing product stewardship and extended producer responsibility for refrigerator waste.

    PubMed

    Nicol, Scott; Thompson, Shirley

    2007-06-01

    Today, over-consumption, pollution and resource depletion threaten sustainability. Waste management policies frequently fail to reduce consumption, prevent pollution, conserve resources and foster sustainable products. However, waste policies are changing to focus on lifecycle impacts of products from the cradle to the grave by extending the responsibilities of stakeholders to post-consumer management. Product stewardship and extended producer responsibility are two policies in use, with radically different results when compared for one consumer product, refrigerators. North America has enacted product stewardship policies that fail to require producers to take physical or financial responsibility for recycling or for environmentally sound disposal, so that releases of ozone depleting substances routinely occur, which contribute to the expanding the ozone hole. Conversely, Europe's Waste Electrical and Electronic Equipment (WEEE) Directive requires extended producer responsibility, whereby producers collect and manage their own post-consumer waste products. WEEE has resulted in high recycling rates of greater than 85%, reduced emissions of ozone-depleting substances and other toxins, greener production methods, such as replacing greenhouse gas refrigerants with environmentally friendly hydrocarbons and more reuse of refrigerators in the EU in comparison with North America. PMID:17612322

  1. Cardiovascular reactivity, stress, and physical activity

    PubMed Central

    Huang, Chun-Jung; Webb, Heather E.; Zourdos, Michael C.; Acevedo, Edmund O.

    2013-01-01

    Psychological stress has been proposed as a major contributor to the progression of cardiovascular disease (CVD). Acute mental stress can activate the sympathetic-adrenal-medullary (SAM) axis, eliciting the release of catecholamines (NE and EPI) resulting in the elevation of heart rate (HR) and blood pressure (BP). Combined stress (psychological and physical) can exacerbate these cardiovascular responses, which may partially contribute to the elevated risk of CVD and increased proportionate mortality risks experienced by some occupations (e.g., firefighting and law enforcement). Studies have supported the benefits of physical activity on physiological and psychological health, including the cardiovascular response to acute stress. Aerobically trained individuals exhibit lower sympathetic nervous system (e.g., HR) reactivity and enhanced cardiovascular efficiency (e.g., lower vascular reactivity and decreased recovery time) in response to physical and/or psychological stress. In addition, resistance training has been demonstrated to attenuate cardiovascular responses and improve mental health. This review will examine stress-induced cardiovascular reactivity and plausible explanations for how exercise training and physical fitness (aerobic and resistance exercise) can attenuate cardiovascular responses to stress. This enhanced functionality may facilitate a reduction in the incidence of stroke and myocardial infarction. Finally, this review will also address the interaction of obesity and physical activity on cardiovascular reactivity and CVD. PMID:24223557

  2. Vasovagal oscillations and vasovagal responses produced by the vestibulo-sympathetic reflex in the rat.

    PubMed

    Yakushin, Sergei B; Martinelli, Giorgio P; Raphan, Theodore; Xiang, Yongqing; Holstein, Gay R; Cohen, Bernard

    2014-01-01

    Sinusoidal galvanic vestibular stimulation (sGVS) induces oscillations in blood pressure (BP) and heart rate (HR), i.e., vasovagal oscillations, as well as transient decreases in BP and HR, i.e., vasovagal responses, in isoflurane-anesthetized rats. We determined the characteristics of the vasovagal oscillations, assessed their role in the generation of vasovagal responses, and determined whether they could be induced by monaural as well as by binaural sGVS and by oscillation in pitch. Wavelet analyses were used to determine the power distributions of the waveforms. Monaural and binaural sGVS and pitch generated vasovagal oscillations at the frequency and at twice the frequency of stimulation. Vasovagal oscillations and vasovagal responses were maximally induced at low stimulus frequencies (0.025-0.05 Hz). The oscillations were attenuated and the responses were rarely induced at higher stimulus frequencies. Vasovagal oscillations could occur without induction of vasovagal responses, but vasovagal responses were always associated with a vasovagal oscillation. We posit that the vasovagal oscillations originate in a low frequency band that, when appropriately activated by strong sympathetic stimulation, can generate vasovagal oscillations as a precursor for vasovagal responses and syncope. We further suggest that the activity responsible for the vasovagal oscillations arises in low frequency, otolith neurons with orientation vectors close to the vertical axis of the head. These neurons are likely to provide critical input to the vestibulo-sympathetic reflex to increase BP and HR upon changes in head position relative to gravity, and to contribute to the production of vasovagal oscillations and vasovagal responses and syncope when the baroreflex is inactivated. PMID:24772102

  3. Cardiovascular and sympathetic responses to a mental stress task in young patients with hypertension and/or obesity.

    PubMed

    Garafova, A; Penesova, A; Cizmarova, E; Marko, A; Vlcek, M; Jezova, D

    2014-01-01

    Present study was aimed to investigate sympathetic responses to mental stress with hypothesis that the presence of obesity in patients with hypertension has a modifying effect. Young male subjects, 8 with hypertension grade I, with BMI 25 kg/m(2) (HT), 10 with hypertension grade I, and BMI 30 kg/m(2) (HT OB), 14 healthy controls with BMI 30 kg/m(2) (OB), and 13 healthy controls with BMI 25 kg/m(2) (C) underwent the Stroop test. ECG was recorded continuously to evaluate heart rate variability (HRV). Blood pressure (BP) and catecholamine concentrations were measured at baseline, at the end of mental stress test and 15 min thereafter. Patients with HT demonstrated increased adrenaline concentrations and enhanced stress-induced noradrenaline release compared to that in healthy controls. In obese subjects, stress-induced increase of systolicBP was lower compared to lean individuals. Stress exposure induced a significant rise in the low frequency power component of HRV, however the increase was lower in the HT OB group compared to C. Obesity in patients with hypertension did not lead to a different reaction in comparison with lean hypertensive subjects. The present data demonstrate higher sympathoadrenal activity in early-stage of hypertension. Obesity is connected with higher resting systolicBP and modifies the HRV response to mental stress. PMID:25669677

  4. Effects of nasal continuous positive airway pressure and oxygen supplementation on norepinephrine kinetics and cardiovascular responses in obstructive sleep apnea.

    PubMed

    Mills, Paul J; Kennedy, Brian P; Loredo, Jose S; Dimsdale, Joel E; Ziegler, Michael G

    2006-01-01

    Obstructive sleep apnea (OSA) is characterized by noradrenergic activation. Nasal continuous positive airway pressure (CPAP) is the treatment of choice and has been shown to effectively reduce elevated norepinephrine (NE) levels. This study examined whether the reduction in NE after CPAP is due to an increase in NE clearance and/or a decrease of NE release rate. Fifty CPAP-naive OSA patients with an apnea-hypopnea index >15 were studied. NE clearance and release rates, circulating NE levels, urinary NE excretion, and blood pressure and heart rate were determined before and after 14 days of CPAP, placebo CPAP (CPAP administered at ineffective pressure), or oxygen supplementation. CPAP led to a significant increase in NE clearance (P < or = 0.01), as well as decreases in plasma NE levels (P < or = 0.018) and daytime (P < 0.001) and nighttime (P < 0.05) NE excretion. NE release rate was unchanged with treatment. Systolic (P < or = 0.013) and diastolic (P < or = 0.026) blood pressure and heart rate (P < or = 0.014) were decreased in response to CPAP but not in response to oxygen or placebo CPAP treatment. Posttreatment systolic blood pressure was best predicted by pretreatment systolic blood pressure and posttreatment NE clearance and release rate (P < 0.01). The findings indicate that one of the mechanisms through which CPAP reduces NE levels is through an increase in the clearance of NE from the circulation. PMID:16357087

  5. Variable primary producer responses to nutrient and temperature manipulations in mesocosms: temperature usually trumps nutrient effects

    EPA Science Inventory

    Mesocosm experiments have been used to evaluate the impacts of nutrient loading on estuarine plant communities in order to develop nutrient response relationships. Mesocosm eutrophication studies tend to focus on long residence time systems. In the Pacific Northwest, many estuari...

  6. Positive Cardiovascular Health: A Timely Convergence.

    PubMed

    Labarthe, Darwin R; Kubzansky, Laura D; Boehm, Julia K; Lloyd-Jones, Donald M; Berry, Jarett D; Seligman, Martin E P

    2016-08-23

    Two concepts, positive health and cardiovascular health, have emerged recently from the respective fields of positive psychology and preventive cardiology. These parallel constructs are converging to foster positive cardiovascular health and a growing collaboration between psychologists and cardiovascular scientists to achieve significant improvements in both individual and population cardiovascular health. We explore these 2 concepts and note close similarities in the measures that define them, the health states that they aim to produce, and their intended long-term clinical and public health outcomes. We especially examine subjective health assets, such as optimism, that are a core focus of positive psychology, but have largely been neglected in preventive cardiology. We identify research to date on positive cardiovascular health, discuss its strengths and limitations thus far, and outline directions for further engagement of cardiovascular scientists with colleagues in positive psychology to advance this new field. PMID:27539179

  7. Agroinfiltration by cytokinin-producing Agrobacterium sp. strain GV3101 primes defense responses in Nicotiana tabacum.

    PubMed

    Sheikh, Arsheed Hussain; Raghuram, Badmi; Eschen-Lippold, Lennart; Scheel, Dierk; Lee, Justin; Sinha, Alok Krishna

    2014-11-01

    Transient infiltrations in tobacco are commonly used in plant studies, but the host response to different disarmed Agrobacterium strains is not fully understood. The present study shows that pretreatment with disarmed Agrobacterium tumefaciens GV3101 primes the defense response to subsequent infection by Pseudomonas syringae in Nicotiana tabacum. The presence of a trans-zeatin synthase (tzs) gene in strain GV3101 may be partly responsible for the priming response, as the tzs-deficient Agrobacterium sp. strain LBA4404 only weakly imparts such responses. Besides inducing the expression of defense-related genes like PR-1 and NHL10, GV3101 pretreatment increased the expression of tobacco mitogen-activated protein kinase (MAPK) pathway genes like MEK2, WIPK (wound-induced protein kinase), and SIPK (salicylic acid-induced protein kinase). Furthermore, the GV3101 strain showed a stronger effect than the LBA4404 strain in activating phosphorylation of the tobacco MAPK, WIPK and SIPK, which presumably prime the plant immune machinery. Lower doses of exogenously applied cytokinins increased the activation of MAPK, while higher doses decreased the activation, suggesting a balanced level of cytokinins is required to generate defense response in planta. The current study serves as a cautionary warning for plant researchers over the choice of Agrobacterium strains and their possible consequences on subsequent pathogen-related studies. PMID:25054409

  8. Cardiovascular effects of basal insulins.

    PubMed

    Mannucci, Edoardo; Giannini, Stefano; Dicembrini, Ilaria

    2015-01-01

    Basal insulin is an important component of treatment for both type 1 and type 2 diabetes. One of the principal aims of treatment in patients with diabetes is the prevention of diabetic complications, including cardiovascular disease. There is some evidence, although controversial, that attainment of good glycemic control reduces long-term cardiovascular risk in both type 1 and type 2 diabetes. The aim of this review is to provide an overview of the potential cardiovascular safety of the different available preparations of basal insulin. Current basal insulin (neutral protamine Hagedorn [NPH], or isophane) and basal insulin analogs (glargine, detemir, and the more recent degludec) differ essentially by various measures of pharmacokinetic and pharmacodynamic effects in the bloodstream, presence and persistence of peak action, and within-subject variability in the glucose-lowering response. The currently available data show that basal insulin analogs have a lower risk of hypoglycemia than NPH human insulin, in both type 1 and type 2 diabetes, then excluding additional harmful effects on the cardiovascular system mediated by activation of the adrenergic system. Given that no biological rationale for a possible difference in cardiovascular effect of basal insulins has been proposed so far, available meta-analyses of publicly disclosed randomized controlled trials do not show any signal of increased risk of major cardiovascular events between the different basal insulin analogs. However, the number of available cardiovascular events in these trials is very small, preventing any clear-cut conclusion. The results of an ongoing clinical trial comparing glargine and degludec with regard to cardiovascular safety will provide definitive evidence. PMID:26203281

  9. Cardiovascular effects of basal insulins

    PubMed Central

    Mannucci, Edoardo; Giannini, Stefano; Dicembrini, Ilaria

    2015-01-01

    Basal insulin is an important component of treatment for both type 1 and type 2 diabetes. One of the principal aims of treatment in patients with diabetes is the prevention of diabetic complications, including cardiovascular disease. There is some evidence, although controversial, that attainment of good glycemic control reduces long-term cardiovascular risk in both type 1 and type 2 diabetes. The aim of this review is to provide an overview of the potential cardiovascular safety of the different available preparations of basal insulin. Current basal insulin (neutral protamine Hagedorn [NPH], or isophane) and basal insulin analogs (glargine, detemir, and the more recent degludec) differ essentially by various measures of pharmacokinetic and pharmacodynamic effects in the bloodstream, presence and persistence of peak action, and within-subject variability in the glucose-lowering response. The currently available data show that basal insulin analogs have a lower risk of hypoglycemia than NPH human insulin, in both type 1 and type 2 diabetes, then excluding additional harmful effects on the cardiovascular system mediated by activation of the adrenergic system. Given that no biological rationale for a possible difference in cardiovascular effect of basal insulins has been proposed so far, available meta-analyses of publicly disclosed randomized controlled trials do not show any signal of increased risk of major cardiovascular events between the different basal insulin analogs. However, the number of available cardiovascular events in these trials is very small, preventing any clear-cut conclusion. The results of an ongoing clinical trial comparing glargine and degludec with regard to cardiovascular safety will provide definitive evidence. PMID:26203281

  10. Cardiovascular Pharmacogenomics

    PubMed Central

    Roden, Dan M.; Johnson, Julie A.; Kimmel, Steven; Krauss, Ronald M.; Medina, Marisa Wong; Shuldiner, Alan; Wilke, Russell A.

    2011-01-01

    Patients vary in their responses to drug therapy, and some of that variability is genetically-determined. This review outlines general approaches used to identify genetic variation that influences drug response. Examples from specific therapeutic areas are presented: cholesterol management, arrhythmias, heart failure, hypertension, warfarin anticoagulation, and anti-platelet agents. A brief view of potential pathways to implementation is presented. PMID:21921273

  11. Cardiovascular regulation in microgravity

    NASA Technical Reports Server (NTRS)

    Blomqvist, C. G.; Lane, L. D.; Wright, S. J.; Meny, G. M.; Buckey, J. C.; Levine, B. D.; Gaffney, F. A.; Watenpaugh, D. E.; Arbeille, P.; Baisch, F.

    1997-01-01

    The human cardiovascular adaptation to microgravity was investigated in the framework of the German Spacelab D2 mission. Preflight and postflight studies were performed to examine the relationship between disuse atrophy and the function of cardiac and skeletal muscles. Special attention was given to fluid load responses and postflight orthostatic hypotension. The preflight measurements were obtained, in supine and sitting positions. These measurements, carried out in the four D2 crew members, were performed six and nine months before flight and on mission day number five. The results obtained on the male crew showed that the stroke volume data from microgravity are virtually identical to preflight measurements in the sitting position.

  12. TOXICOLOGICAL AND PHYSIOLOGICAL RESPONSES OF THE FISH, 'LEIOSTOMUS XANTHURUS', EXPOSED TO CHLORINE PRODUCED OXIDANTS

    EPA Science Inventory

    The sublethal and lethal effects of chlorine produced oxidants (CPO) on juveniles of the estuarine teleost, Leiostomus xanthurus, were investigated in flowing water tests conducted at 30 plus or minus 1C and 26 to 31% salinity. Short-term LT50 tests were conducted at two nominal ...

  13. BIRTH MALFORMATIONS AND OTHER ADVERSE PERINATAL OUTCOMES IN FOUR U.S. WHEAT PRODUCING STATES: RESPONSE

    EPA Science Inventory

    Chlorophenoxy herbicides are widely used in the U.S. and Western Europe for broadleaf weed control in grain farming and park maintenance. Most of the spring and durum wheat produced in the U.S. is grown in Minnesota, Montana, North Dakota, and South Dakota, with over 85% of the a...

  14. Adaptive plasticity in vestibular influences on cardiovascular control

    NASA Technical Reports Server (NTRS)

    Yates, B. J.; Holmes, M. J.; Jian, B. J.

    2000-01-01

    Data collected in both human subjects and animal models indicate that the vestibular system influences the control of blood pressure. In animals, peripheral vestibular lesions diminish the capacity to rapidly and accurately make cardiovascular adjustments to changes in posture. Thus, one role of vestibulo-cardiovascular influences is to elicit changes in blood distribution in the body so that stable blood pressure is maintained during movement. However, deficits in correcting blood pressure following vestibular lesions diminish over time, and are less severe when non-labyrinthine sensory cues regarding body position in space are provided. These observations show that pathways that mediate vestibulo-sympathetic reflexes can be subject to plastic changes. This review considers the adaptive plasticity in cardiovascular responses elicited by the central vestibular system. Recent data indicate that the posterior cerebellar vermis may play an important role in adaptation of these responses, such that ablation of the posterior vermis impairs recovery of orthostatic tolerance following subsequent vestibular lesions. Furthermore, recent experiments suggest that non-labyrinthine inputs to the central vestibular system may be important in controlling blood pressure during movement, particularly following vestibular dysfunction. A number of sensory inputs appear to be integrated to produce cardiovascular adjustments during changes in posture. Although loss of any one of these inputs does not induce lability in blood pressure, it is likely that maximal blood pressure stability is achieved by the integration of a variety of sensory cues signaling body position in space.

  15. Cardiovascular response to exercise training in the systemic right ventricle of adults with transposition of the great arteries

    PubMed Central

    Shafer, K M; Janssen, L; Carrick-Ranson, G; Rahmani, S; Palmer, D; Fujimoto, N; Livingston, S; Matulevicius, S A; Forbess, L W; Brickner, B; Levine, B D

    2015-01-01

    We aimed to assess the haemodynamic effects of exercise training in transposition of the great arteries (TGA) patients with systemic right ventricles (SRVs). TGA patients have limited exercise tolerance and early mortality due to systemic (right) ventricular failure. Whether exercise training enhances or injures the SRV is unclear. Fourteen asymptomatic patients (34 ± 10 years) with TGA and SRV were enrolled in a 12 week exercise training programme (moderate and high-intensity workouts). Controls were matched on age, gender, BMI and physical activity. Exercise testing pre- and post- training included: (a) submaximal and peak; (b) prolonged (60 min) submaximal endurance and (c) high-intensity intervals. Oxygen uptake (; Douglas bag technique), cardiac output (, foreign-gas rebreathing), ventricular function (echocardiography and cardiac MRI) and serum biomarkers were assessed. TGA patients had lower peak , , and stroke volume (SV), a blunted / slope, and diminished SV response to exercise (SV increase from rest: TGA = 15.2%, controls = 68.9%, P < 0.001) compared with controls. After training, TGA patients increased peak by 6 ± 8.5%, similar to controls (interaction P = 0.24). The magnitude of SV reserve on initial testing correlated with training response (r = 0.58, P = 0.047), though overall, no change in peak was observed. High-sensitivity troponin T (hs-TnT) and N-terminal prohormone of brain naturetic peptide (NT pro-BNP) were low and did not change with acute exercise or after training. Our data show that TGA patients with SRVs in this study safely participated in exercise training and improved peak . Neither prolonged submaximal exercise, nor high-intensity intervals, nor short-term exercise training seem to injure the systemic right ventricle. Key Points Patients with transposition of the great arteries (TGA) and systemic right ventricles have premature congestive heart failure; there is also a growing concern that athletes who perform

  16. A collaborative user-producer assessment of earthquake-response products

    USGS Publications Warehouse

    Gomberg, Joan; Jakobitz, Allen

    2013-01-01

    The U.S. Geological Survey (USGS) and the Washington State Emergency Management Division assessed how well USGS earthquake-response products met the needs of emergency managers at county and local levels. Focus-group responses guided development of new products for testing in a regional-scale earthquake exercise. The assessment showed that (1) emergency responders consider most USGS products unnecessary after the first few postearthquake hours because the products are predictors, and responders are quickly immersed in reality; (2) during crises a significant fraction of personnel engaged in emergency response are drawn from many sectors, increasing the breadth of education well beyond emergency management agencies; (3) many emergency personnel do not use maps; and (4) information exchange, archiving, and analyses involve mechanisms and technical capabilities that vary among agencies, so widely used products must be technically versatile and easy to use.

  17. Cardiovascular response to noise in type A and type B female subjects: Effect of the ovarian cycle

    NASA Astrophysics Data System (ADS)

    Di Nisi, J.; Muzet, A.

    1989-10-01

    The aim of the investigation was to study the heart rate and finger pulse responses during the menstrual cycle in type A and type B female subjects. Nine type A's and nine type B's were selected by using the French version of Bortner's short rating scale questionnaire. They were exposed to noise in three different periods of the menstrual cycle; menses (day 0-2), pre-ovulation (8-10) and post-ovulation (22-24). No significant difference in tonic heart rate level between type A's and type B's was found. The percentages of HRR and FPR were not significantly different for the two types of subjects. However, the amplitude of HRR and FPR were significantly higher in type A's than in type B's. significant differences related to the periods of the menstrual cycle were also found. In type B's, the amplitude of HRR was larger during menses than during the two other periods. In type A's, the amplitude of the FPR was higher during the menses than during the pre-ovulation. The percentage of noise stimuli eliciting HRR and FPR did not vary as a function of the menstrual cycle. These results are discussed in terms of excitability and balance of the autonomic nervous system.

  18. Effects of nutrition on disease and life span. I. Immune responses, cardiovascular pathology, and life span in MRL mice.

    PubMed Central

    Mark, D. A.; Alonso, D. R.; Quimby, F.; Thaler, H. T.; Kim, Y. T.; Fernandes, G.; Good, R. A.; Weksler, M. E.

    1984-01-01

    Mice of the autoimmune, lymphoproliferative strain MRL/lpr and the congenic, nonlymphoproliferative strain MRL/n were fed one of six diets from weaning on-ward. These mice were sacrificed at 3 or 5 months of age. Low fat diets resulted in lower cholesterol and higher triglyceride levels than did cholesterol-containing high-fat diets. Caloric restriction of MRL/lpr mice was associated with an increased plaque-forming cell response to trinitrophenylated polyacrylamide beads, less lymphoproliferation, and less severe glomerulonephritis. Diet did not affect the incidence of autoimmune vasculitis in MRL/lpr mice sacrificed at 5 months. MRL/lpr mice fed a low-fat, calorically restricted diet from 5 months of age to death lived longer than mice which were fed ad libitum a cholesterol-containing, high-fat diet. At death, MRL/lpr mice fed the former diet had the autoimmune vasculitis which had been evident in mice killed at 5 months, whereas mice fed the latter diet, in addition to the vasculitis, had a high incidence of atherosclerotic lesions of intrarenal and aortic branch arteries. Images Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:6333184

  19. Photoconductive detectors with fast temporal response for laser produced plasma experiments

    SciTech Connect

    May, M. J.; Halvorson, C.; Perry, T.; Weber, F.; Young, P.; Silbernagel, C.

    2008-10-15

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires x-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different x-ray sensitive photoconductive detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using x-ray radiation from a synchrotron radiation source are presented.

  20. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments.

    SciTech Connect

    May, M; Halvorson, C; Perry, T; Weber, F; Young, P; Silbernagel, C

    2008-05-06

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different X-ray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  1. Photoconductive Detectors with Fast Temporal Response for Laser Produced Plasma Experiments

    SciTech Connect

    M. J. May, C. Halvorson, T. Perry, F. Weber, P. Young, C. Silbernagel

    2008-06-01

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires X-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different Xray sensitive Photoconductive Detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using X-ray light from a synchrotron light source are presented.

  2. Photoconductive detectors with fast temporal response for laser produced plasma experiments.

    PubMed

    May, M J; Halvorson, C; Perry, T; Weber, F; Young, P; Silbernagel, C

    2008-10-01

    Processes during laser plasma experiments typically have time scales that are less than 100 ps. The measurement of these processes requires x-ray detectors with fast temporal resolution. We have measured the temporal responses and linearity of several different x-ray sensitive photoconductive detectors (PCDs). The active elements of the detectors investigated include both diamond (natural and synthetic) and GaAs crystals. The typical time responses of the GaAs PCDs are approximately 60 ps, respectively. Some characterizations using x-ray radiation from a synchrotron radiation source are presented. PMID:19044466

  3. Factors affecting the response to the specific treatment of several forms of clinical anestrus in high producing dairy cows.

    PubMed

    López-Gatius, F; Mirzaei, A; Santolaria, P; Bech-Sàbat, G; Nogareda, C; García-Ispierto, I; Hanzen, Ch; Yániz, J L

    2008-06-01

    This study was designed to examine estrous response rates to the therapeutic treatment of clinical anestrus in high producing dairy cows and to identify the factors that could affect these rates. Cows with silent ovulation (Subestrus group), cystic ovarian disease (Cyst group) or ovarian hypofunction (OH group) were given specific treatment for their disorder. Data were derived from 1764 treatments in cows producing a mean of 45.4 kg of milk upon treatment including: 889 subestrous cows, 367 cystic cows and 508 cows with ovarian hypofunction. Cows showing estrus following treatment exhibited a similar pregnancy rate to cows attaining natural estrus used as reference: 33% (337/1006) and 35% (626/1796), respectively. No significant differences in pregnancy rates were observed among the Subestrus, Cyst and OH groups (34% (196/571), 34% (44/130), 32% (97/305), respectively. Based on the odds ratio, an estrous response for all groups was less likely to occur in cows that had suffered previous anestrus, compared to cows that were anestrous for the first time, whereas the likelihood of an estrous response increased in cows treated after 90 days in milk. Our results indicate that previous anestrus and a late stage of lactation can have a negative and positive effect, respectively, on the estrous response to the specific treatment of clinical anestrus shown by high producing dairy cows. Treatment targeted at each type of clinical anestrus can render similar pregnancy rates to those shown by cows in natural estrus. PMID:18359070

  4. Altitude matters: differences in cardiovascular and respiratory responses to hypoxia in bar-headed geese reared at high and low altitudes.

    PubMed

    Lague, Sabine L; Chua, Beverly; Farrell, Anthony P; Wang, Yuxiang; Milsom, William K

    2016-07-01

    Bar-headed geese (Anser indicus) fly at high altitudes during their migration across the Himalayas and Tibetan plateau. However, we know relatively little about whether rearing at high altitude (i.e. phenotypic plasticity) facilitates this impressive feat because most of what is known about their physiology comes from studies performed at sea level. To provide this information, a comprehensive analysis of metabolic, cardiovascular and ventilatory responses to progressive decreases in the equivalent fractional composition of inspired oxygen (FiO2 : 0.21, 0.12, 0.09, 0.07 and 0.05) was made on bar-headed geese reared at either high altitude (3200 m) or low altitude (0 m) and on barnacle geese (Branta leucopsis), a low-altitude migrating species, reared at low altitude (0 m). Bar-headed geese reared at high altitude exhibited lower metabolic rates and a modestly increased hypoxic ventilatory response compared with low-altitude-reared bar-headed geese. Although the in vivo oxygen equilibrium curves and blood-oxygen carrying capacity did not differ between the two bar-headed goose study groups, the blood-oxygen carrying capacity was higher than that of barnacle geese. Resting cardiac output also did not differ between groups and increased at least twofold during progressive hypoxia, initially as a result of increases in stroke volume. However, cardiac output increased at a higher FiO2  threshold in bar-headed geese raised at high altitude. Thus, bar-headed geese reared at high altitude exhibited a reduced oxygen demand at rest and a modest but significant increase in oxygen uptake and delivery during progressive hypoxia compared with bar-headed geese reared at low altitude. PMID:27385754

  5. Disagreement between standard transthoracic impedance cardiography and the automated transthoracic electrical bioimpedance method in estimating the cardiovascular responses to phenylephrine and isoprenaline in healthy man.

    PubMed Central

    De Mey, C; Enterling, D

    1993-01-01

    1. Impedance cardiography is a well-established noninvasive method to assess within-subject changes of cardiovascular function. We compared the standard approach (ZCG) which requires tedious signal analysis with an automated approach (TEB: NCCOM 3) with its own specific equipment, algorithms and equations in order to assess agreement of the method-specific measurements and calculations. 2. Ten healthy men were studied on two occasions with either ZCG or TEB, at rest and at the end of 5 min i.v.-infusions with 1 microgram min-1 isoprenaline and 100 micrograms min-1 phenylephrine. 3. There was good agreement for the method-independent changes (HR, SBP/DBP), but there were large differences for method-specific measurements: dZ/dtmax [TEB-ZCG] = -0.68, CI: -0.83 to -0.53 ohm s-1, PEP [TEB-ZCG] = -22.1, CI: -35.0 to -9.2 ms and QS2c [TEB-ZCG] = -16.5, CI: -32.4 to -0.6 ms and for the calculated stroke volume SV [TEB-ZCG] = 30.3, CI: 15.5 to 45.2 ml. The responses of dZ/dtmax and SV to isoprenaline and phenylephrine, although qualitatively similar, reached no quantitative agreement either. A substantial disagreement was evident for the STI responses to isoprenaline where TEB failed to detect the expected reduction of VETc and thus grossly underestimated the shortening of QS2c. 4. It is concluded that TEB-measurements and -calculations did not agree with standard ZCG, that the methods, albeit related, cannot be considered as interchangeable and that suspicion is justified that TEB might yield erroneous results under specific circumstances. PMID:8485014

  6. Cardiovascular responses to the ingestion of sugary drinks using a randomised cross-over study design: Does glucose attenuate the blood pressure-elevating effect of fructose?

    PubMed

    Grasser, Erik K; Dulloo, Abdul; Montani, Jean-Pierre

    2014-07-28

    Overconsumption of sugar-sweetened beverages has been implicated in the pathogenesis of CVD. The objective of the present study was to elucidate acute haemodynamic and microcirculatory responses to the ingestion of sugary drinks made from sucrose, glucose or fructose at concentrations similar to those often found in commercial soft drinks. In a randomised cross-over study design, twelve young healthy human subjects (seven men) ingested 500 ml tap water in which was dissolved 60 g of either sucrose, glucose or fructose, or an amount of fructose equivalent to that present in sucrose (i.e. 30 g fructose). Continuous cardiovascular monitoring was performed for 30 min before and at 60 min after ingestion of sugary drinks, and measurements included beat-to-beat blood pressure (BP) and impedance cardiography. Additionally, microvascular endothelial function testing was performed after iontophoresis of acetylcholine and sodium nitroprusside using laser Doppler flowmetry. Ingestion of fructose (60 or 30 g) increased diastolic and mean BP to a greater extent than the ingestion of 60 g of either glucose or sucrose (P< 0.05). Ingestion of sucrose and glucose increased cardiac output (CO; P< 0.05), index of contractility (P< 0.05) and stroke volume (P< 0.05), but reduced total peripheral resistance (TPR; P< 0.05), which contrasts with the tendency of fructose (60 and 30 g) to increase resistance. Microvascular endothelial function did not differ in response to the ingestion of various sugary drinks. In conclusion, ingestion of fructose, but not sucrose, increases BP in healthy human subjects. Although sucrose comprises glucose and fructose, its changes in TPR and CO are more related to glucose than to fructose. PMID:24780643

  7. Microinjection of muscimol into the periaqueductal gray suppresses cardiovascular and neuroendocrine response to air jet stress in conscious rats

    PubMed Central

    de Menezes, Rodrigo C. A.; Zaretsky, Dmitry V.; Sarkar, Sumit; Fontes, Marco A. P.; DiMicco, Joseph A.

    2008-01-01

    Microinjection of the neuronal inhibitor muscimol into the dorsomedial hypothalamus (DMH) suppresses increases in heart rate (HR), mean arterial pressure (MAP), and circulating levels of adrenocorticotropic hormone (ACTH) evoked in air jet stress in conscious rats. Similar injection of muscimol into the caudal region of the lateral/dorsolateral periaqueductal gray (l/dlPAG) reduces autonomic responses evoked from the DMH, leading to the suggestion that neurons in the l/dlPAG may represent a descending relay for DMH-induced increases in HR and MAP. Here, we examined the role of neuronal activity in the caudal l/dlPAG on the increases in MAP, HR, and plasma ACTH seen in air jet stress in rats. Microinjection of muscimol into the caudal l/dlPAG reduced stress-induced increases in HR and MAP, while identical injections into sites just dorsal or into the rostral l/dlPAG had no effect. Microinjection of a combination of the glutamate receptor antagonists 2-amino-5-phosphonopentanoate (AP5) and 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX) into the caudal l/dlPAG decreased stress-induced increases in HR alone only at the end of the 20-min stress period but significantly accelerated return to baseline. Surprisingly, microinjection of muscimol into the caudal l/dlPAG also reduced the stress-induced increase in plasma ACTH by 51%. Compared with unstressed control rats, rats exposed to air jet stress exhibited ∼3 times the number of Fos-positive neurons in the l/dlPAG. These findings suggest that neurons in the l/dlPAG are activated in air jet stress and that this activity contributes to increases in HR, MAP, and plasma ACTH. PMID:18650321

  8. Rheological properties of a biological thermo-responsive hydrogel produced from soybean oil polymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rheological properties of a newly developed biological thermo-hydrogel made from vegetable oil were investigated. The material named HPSO-HG is a hydrolytic product of polymerized soybean oil (PSO). HPSO-HG is a thermo-responsive gel, and it exhibited viscoelastic behavior above 2% (wt.%) at roo...

  9. Stream mesocosm response sensitivities to simulated ion stress in produced waters from resource extraction activities

    EPA Science Inventory

    To increase the ecological relevance of laboratory exposures intent on determining species sensitivity to ion stress from resource extraction activities we have conducted several stream mesocosm dosing studies that pair single-species and community-level responses in-situ and all...

  10. Short chain fatty acid production and glucose responses by methane producers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fermentation by gut microbiota has been linked to physiologic responses in the host. Methanogenic gut bacteria may remove more carbon from indigestible food matrices especially poorly digested carbohydrates. We sought to assess the effects of methane production on short chain fatty acid (SCFA) con...

  11. Response Cards: A Proven Method for Producing Active Student Engagement during Math Instruction

    ERIC Educational Resources Information Center

    Cipani, Ennio

    2007-01-01

    This article presents an instructional delivery method, termed response cards, that has received empirical validation in several studies. With various federal and state mandates and measures of accountability, schools are under increasing pressure to use methods that have received validation of their effectiveness in research studies. Response…

  12. Arepas made from ß-glucans enriched corn flour produced low metabolic responses in healthy subjects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn is one of the most important cereals for the nutrition of large groups of the Latin American population and arepa is a very popular corn-based food preparation. In order to study the arepa consumption effects on glucose and insulin response when ß-glucans were added to this preparation, three ...

  13. Specificity of Cardiovascular Endurance Training.

    ERIC Educational Resources Information Center

    Riley, Calberth B., Jr.; Johnson, James H.

    This study determined the specificity of cardiovascular endurance training on a bicycle ergometer. Eighteen male subjects were tested on a heart rate response test of 150 beats per minute on a bicycle ergometer at the pace of 50 revolutions per minute (rpm) and at 160 beats per minute at 60 and 80 rpm, with the resistance equal to the force of…

  14. Tissue-Specific Activation of a Single Gustatory Receptor Produces Opposing Behavioral Responses in Drosophila

    PubMed Central

    Joseph, Ryan M.; Heberlein, Ulrike

    2012-01-01

    Understanding sensory systems that perceive environmental inputs and neural circuits that select appropriate motor outputs is essential for studying how organisms modulate behavior and make decisions necessary for survival. Drosophila melanogaster oviposition is one such important behavior, in which females evaluate their environment and choose to lay eggs on substrates they may find aversive in other contexts. We employed neurogenetic techniques to characterize neurons that influence the choice between repulsive positional and attractive egg-laying responses toward the bitter-tasting compound lobeline. Surprisingly, we found that neurons expressing Gr66a, a gustatory receptor normally involved in avoidance behaviors, receive input for both attractive and aversive preferences. We hypothesized that these opposing responses may result from activation of distinct Gr66a-expressing neurons. Using tissue-specific rescue experiments, we found that Gr66a-expressing neurons on the legs mediate positional aversion. In contrast, pharyngeal taste cells mediate the egg-laying attraction to lobeline, as determined by analysis of mosaic flies in which subsets of Gr66a neurons were silenced. Finally, inactivating mushroom body neurons disrupted both aversive and attractive responses, suggesting that this brain structure is a candidate integration center for decision-making during Drosophila oviposition. We thus define sensory and central neurons critical to the process by which flies decide where to lay an egg. Furthermore, our findings provide insights into the complex nature of gustatory perception in Drosophila. We show that tissue-specific activation of bitter-sensing Gr66a neurons provides one mechanism by which the gustatory system differentially encodes aversive and attractive responses, allowing the female fly to modulate her behavior in a context-dependent manner. PMID:22798487

  15. Bortezomib produces high hematological response rates with prolonged renal survival in monoclonal immunoglobulin deposition disease.

    PubMed

    Cohen, Camille; Royer, Bruno; Javaugue, Vincent; Szalat, Raphael; El Karoui, Khalil; Caulier, Alexis; Knebelmann, Bertrand; Jaccard, Arnaud; Chevret, Sylvie; Touchard, Guy; Fermand, Jean-Paul; Arnulf, Bertrand; Bridoux, Frank

    2015-11-01

    Monoclonal immunoglobulin deposition disease (MIDD) is a rare complication of plasma cell disorders, defined by linear Congo red-negative deposits of monoclonal light chain, heavy chain, or both along basement membranes. While renal involvement is prominent, treatment strategies, such as the impact of novel anti-myeloma agents, remain poorly defined. Here we retrospectively studied 49 patients with MIDD who received a median of 4.5 cycles of intravenous bortezomib plus dexamethasone. Of these, 25 received no additional treatment, 18 also received cyclophosphamide, while 6 also received thalidomide or lenalidomide. The hematological diagnoses identified 38 patients with monoclonal gammopathy of renal significance, 10 with symptomatic multiple myeloma, and 1 with Waldenstrom macroglobulinemia. The overall hematologic response rate, based on the difference between involved and uninvolved serum-free light chains (dFLCs), was 91%. After median follow-up of 54 months, 5 patients died and 10 had reached end-stage renal disease. Renal response was achieved in 26 patients, with a 35% increase in median eGFR and an 86% decrease in median 24-h proteinuria. Predictive factors were pre-treatment eGFR over 30 ml/min per 1.73 m(2) and post-treatment dFLC under 40 mg/l; the latter was the sole predictive factor of renal response by multivariable analysis. Thus, bortezomib-based therapy is a promising treatment strategy in MIDD, mainly when used early in the disease course. dFLC response is a favorable prognostic factor for renal survival. PMID:26176826

  16. The Drosophila TNF Eiger Is an Adipokine that Acts on Insulin-Producing Cells to Mediate Nutrient Response.

    PubMed

    Agrawal, Neha; Delanoue, Renald; Mauri, Alessandra; Basco, Davide; Pasco, Matthieu; Thorens, Bernard; Léopold, Pierre

    2016-04-12

    Adaptation of organisms to ever-changing nutritional environments relies on sensor tissues and systemic signals. Identification of these signals would help understand the physiological crosstalk between organs contributing to growth and metabolic homeostasis. Here we show that Eiger, the Drosophila TNF-α, is a metabolic hormone that mediates nutrient response by remotely acting on insulin-producing cells (IPCs). In the condition of nutrient shortage, a metalloprotease of the TNF-α converting enzyme (TACE) family is active in fat body (adipose-like) cells, allowing the cleavage and release of adipose Eiger in the hemolymph. In the brain IPCs, Eiger activates its receptor Grindelwald, leading to JNK-dependent inhibition of insulin production. Therefore, we have identified a humoral connexion between the fat body and the brain insulin-producing cells relying on TNF-α that mediates adaptive response to nutrient deprivation. PMID:27076079

  17. Responsive hydrogels produced via organic sol-gel chemistry for cell culture applications.

    PubMed

    Patil, Smruti; Chaudhury, Pulkit; Clarizia, Lisa; McDonald, Melisenda; Reynaud, Emmanuelle; Gaines, Peter; Schmidt, Daniel F

    2012-08-01

    In this study, we report the synthesis of novel environmentally responsive polyurea hydrogel networks prepared via organic sol-gel chemistry and demonstrate that the networks can stabilize pH while releasing glucose both in simple aqueous media and in mammalian cell culture settings. Hydrogel formulations have been developed based on the combination of an aliphatic triisocyanate with pH-insensitive amine functional polyether and pH-sensitive poly(ethyleneimine) segments in a minimally toxic solvent suitable for the sol-gel reaction. The polyether component of the polyurea network is sufficiently hydrophilic to give rise to some level of swelling independent of environmental pH, while the poly(ethyleneimine) component contains tertiary amine groups providing pH sensitivity to the network in the form of enhanced swelling and release under acidic conditions. The reaction of these materials to form a network is rapid and requires no catalyst. The resultant material exhibits the desired pH-responsive swelling behavior and demonstrates its ability to simultaneously neutralize lactic acid and release glucose in both cell-free culture media and mammalian cell culture, with no detectable evidence of cytotoxicity or changes in cell behavior, in the case of either SA-13 human hybridomas or mouse embryonic stem cells. Furthermore, pH is observed to have a clear effect on the rate at which glucose is released from the hydrogel network. Such characteristics promise to maintain a favorable cell culture environment in the absence of human intervention. PMID:22561670

  18. Long-Term Coffee Consumption and Risk of Cardiovascular Disease: A Systematic Review and a Dose-Response Meta-Analysis of Prospective Cohort Studies

    PubMed Central

    Ding, Ming; Bhupathiraju, Shilpa N; Satija, Ambika; van Dam, Rob M; Hu, Frank B

    2013-01-01

    Background Considerable controversy exists regarding the association between coffee consumption and cardiovascular disease (CVD) risk. A meta-analysis was performed to assess the dose-response relationship of long-term coffee consumption with CVD risk. Methods and Results Pubmed and EMBASE were searched for prospective cohort studies of the relationship between coffee consumption and CVD risk, which included coronary heart disease, stroke, heart failure, and CVD mortality. Thirty-six studies were included with 1,279,804 participants and 36,352 CVD cases. A non-linear relationship of coffee consumption with CVD risk was identified (P for heterogeneity = 0.09, P for trend < 0.001, P for non-linearity < 0.001). Compared with the lowest category of coffee consumption (median: 0 cups/d), the relative risk of CVD was 0.95 (95% CI, 0.87 to 1.03) for the highest (median: 5 cups/d) category, 0.85 (0.80 to 0.90) for the second highest (median: 3.5 cups/d), and 0.89 (0.84 to 0.94) for the third highest category (median: 1.5 cups/d). Looking at separate outcomes, coffee consumption was non-linearly associated with both CHD (P for heterogeneity = 0.001, P for trend < 0.001, P for non-linearity < 0.001) and stroke risks (P for heterogeneity = 0.07, P for trend < 0.001, P for non-linearity< 0.001) (P for trend differences > 0.05). Conclusions A non-linear association between coffee consumption with CVD risk was observed in this meta-analysis. Moderate coffee consumption was inversely significantly associated with CVD risk, with the lowest CVD risk at 3 to 5 cups/d, and heavy coffee consumption was not associated with elevated CVD risk. PMID:24201300

  19. Usefulness of chronotropic incompetence in response to exercise as a predictor of myocardial infarction in middle-aged men without cardiovascular disease.

    PubMed

    Savonen, Kai P; Lakka, Timo A; Laukkanen, Jari A; Rauramaa, Tuomas H; Salonen, Jukka T; Rauramaa, Rainer

    2008-04-01

    An attenuated heart rate (HR) response to exercise, or chronotropic incompetence, has been shown to predict adverse cardiac events in subjects without known cardiovascular disease (CVD). The aim of the present study was to investigate whether chronotropic incompetence independently predicts acute myocardial infarction (AMI) in middle-aged men. In addition to previously established chronotropic incompetence variables, we focused on a new chronotropic incompetence variable, the HR increase from 40% to 100% of maximal work capacity (HR40-100), as a predictor of AMI. The subjects were a representative sample of 1,176 middle-aged men who did not have CVD and did not use HR-lowering medication at baseline. The association of chronotropic incompetence variables with the risk of AMI was examined by Cox regression models including numerous known risk factors for AMI. During an average follow-up of 11.0 years, there were 106 AMIs (9.0%). In Cox multivariable model, the risk of AMI increased by 33% for each SD decrement of 13 beats/min in HR40-100 (95% confidence interval [CI] 9 to 64). When considered concurrently, HR40-100 was the only chronotropic incompetence variable that improved the predictive value of the model containing other risk factors for AMI. Men with a low HR40-100 (<46 beats/min) and a heightened increase in systolic blood pressure (SBP) (>67 mm Hg) were at particularly high risk, with a 3.1-times higher incidence of AMI than those with a normal HR40-100 and SBP increase (95% CI 1.7 to 5.7). In conclusion, a low HR40-100 predicted AMI in men without previous CVD independent of other exercise test or clinical variables. PMID:18359320

  20. Guidance for improving the federal response to foodborne illness outbreaks associated with fresh produce.

    PubMed

    Benson, Sara M

    2010-01-01

    Today, our nation's food supply flows through a complicated chain of farmers, processors, and distributors before reaching consumers. At some point during this process, food can become contaminated with pathogens and it can make people sick. The Food and Drug Administration, along with the Centers for Disease Control, are in charge of fighting an outbreak once it occurs. The CDC first identifies a specific food that is making people ill, and then the FDA steps in to find the source of that contaminated food. This process, however, does not always run smoothly. Historically, these federal agencies have been underfunded and have had few staff dedicated to fighting foodborne illness outbreaks. This means that an outbreak is not always handled effectively or efficiently, which can have devastating effects on innocent industry actors. This Note gives practical guidance to the FDA and CDC for improving its responses to foodborne illness outbreaks so that consumers, as well as innocent industry actors, are protected. PMID:24479238

  1. Infective Juveniles of the Entomopathogenic Nematode, Steinernema feltiae Produce Cryoprotectants in Response to Freezing and Cold Acclimation

    PubMed Central

    Ali, Farman; Wharton, David A.

    2015-01-01

    Steinernema feltiae is a moderately freeze-tolerant entomopathogenic nematode which survives intracellular freezing. We have detected by gas chromatography that infective juveniles of S. feltiae produce cryoprotectants in response to cold acclimation and to freezing. Since the survival of this nematode varies with temperature, we analyzed their cryoprotectant profiles under different acclimation and freezing regimes. The principal cryoprotectants detected were trehalose and glycerol with glucose being the minor component. The amount of cryoprotectants varied with the temperature and duration of exposure. Trehalose was accumulated in higher concentrations when nematodes were acclimated at 5°C for two weeks whereas glycerol level decreased from that of the non-acclimated controls. Nematodes were seeded with a small ice crystal and held at -1°C, a regime that does not produce freezing of the nematodes but their bodies lose water to the surrounding ice (cryoprotective dehydration). This increased the levels of both trehalose and glycerol, with glycerol reaching a higher concentration than trehalose. Nematodes frozen at -3°C, a regime that produces freezing of the nematodes and results in intracellular ice formation, had elevated glycerol levels while trehalose levels did not change. Steinernema feltiae thus has two strategies of cryoprotectant accumulation: one is an acclimation response to low temperature when the body fluids are in a cooled or supercooled state and the infective juveniles produce trehalose before freezing. During this process a portion of the glycerol is converted to trehalose. The second strategy is a rapid response to freezing which induces the production of glycerol but trehalose levels do not change. These low molecular weight compounds are surmised to act as cryoprotectants for this species and to play an important role in its freezing tolerance. PMID:26509788

  2. Cardiovascular Effects of Felypressin

    PubMed Central

    Cecanho, Rodrigo; De Luca, Laurival Antonio; Ranali, José

    2006-01-01

    Cardiovascular effects of felypressin (FEL) were studied in Wistar rats. Heart rate and mean arterial pressure measurements were taken in awake rats treated with vasopressin (AVP), FEL, or epinephrine (EPI). Each group received either an intravenous (IV) or an intracerebroventricular V1 receptor antagonist, saline, area postrema removal, or sham surgery. Analysis of variance and Student-Newman-Keuls (P < .05) were applied. Felypressin and AVP induced a pressor effect, and bradycardia was inhibited by IV V1 antagonist. Intracerebroventricular V1 antagonist and area postrema removal enhanced their pressor effects. Epinephrine induced a higher pressor effect and a similar bradycardia that was not affected by the treatments. It was concluded that FEL depends on V1 receptors to induce pressor and bradycardic effects, and that it produces a high relationship between bradycardia and mean arterial pressure variation depending on area postrema and central V1 receptors. These effects are potentially less harmful to the cardiovascular system than the effects of EPI. PMID:17177590

  3. Tomatoes and cardiovascular health.

    PubMed

    Willcox, Joye K; Catignani, George L; Lazarus, Sheryl

    2003-01-01

    Diet is believed to play a complex role in the development of cardiovascular disease, the leading cause of death in the Western world. Tomatoes, the second most produced and consumed vegetable nationwide, are a rich source of lycopene, beta-carotene, folate, potassium, vitamin C, flavonoids, and vitamin E. The processing of tomatoes may significantly affect the bioavailability of these nutrients. Homogenization, heat treatment, and the incorporation of oil in processed tomato products leads to increased lycopene bioavailability, while some of the same processes cause significant loss of other nutrients. Nutrient content is also affected by variety and maturity. Many of these nutrients may function individually, or in concert, to protect lipoproteins and vascular cells from oxidation, the most widely accepted theory for the genesis of atherosclerosis. This hypothesis has been supported by in vitro, limited in vivo, and many epidemiological studies that associate reduced cardiovascular risk with consumption of antioxidant-rich foods. Other cardioprotective functions provided by the nutrients in tomatoes may include the reduction of low-density lipoprotein (LDL) cholesterol, homocysteine, platelet aggregation, and blood pressure. Because tomatoes include several nutrients associated with theoretical or proven effects and are widely consumed year round, they may be considered a valuable component of a cardioprotective diet. PMID:12587984

  4. Lethal protein produced in response to competition between sibling bacterial colonies

    PubMed Central

    Be’er, Avraham; Ariel, Gil; Kalisman, Oren; Helman, Yael; Sirota-Madi, Alexandra; Zhang, H.P.; Florin, E.-L.; Payne, Shelley M.; Ben-Jacob, Eshel; Swinney, Harry L.

    2010-01-01

    Sibling Paenibacillus dendritiformis bacterial colonies grown on low-nutrient agar medium mutually inhibit growth through secretion of a lethal factor. Analysis of secretions reveals the presence of subtilisin (a protease) and a 12 kDa protein, termed sibling lethal factor (Slf). Purified subtilisin promotes the growth and expansion of P. dendritiformis colonies, whereas Slf is lethal and lyses P. dendritiformis cells in culture. Slf is encoded by a gene belonging to a large family of bacterial genes of unknown function, and the gene is predicted to encode a protein of approximately 20 kDa, termed dendritiformis sibling bacteriocin. The 20 kDa recombinant protein was produced and found to be inactive, but exposure to subtilisin resulted in cleavage to the active, 12 kDa form. The experimental results, combined with mathematical modeling, show that subtilisin serves to regulate growth of the colony. Below a threshold concentration, subtilisin promotes colony growth and expansion. However, once it exceeds a threshold, as occurs at the interface between competing colonies, Slf is then secreted into the medium to rapidly reduce cell density by lysis of the bacterial cells. The presence of genes encoding homologs of dendritiformis sibling bacteriocin in other bacterial species suggests that this mechanism for self-regulation of colony growth might not be limited to P. dendritiformis. PMID:20308591

  5. Pestalone, a new antibiotic produced by a marine fungus in response to bacterial challenge.

    PubMed

    Cueto, M; Jensen, P R; Kauffman, C; Fenical, W; Lobkovsky, E; Clardy, J

    2001-11-01

    The isolation and structure determination of a new chlorinated benzophenone antibiotic, pestalone (1), is described. The new compound was produced by a cultured marine fungus only when a unicellular marine bacterium, strain CNJ-328, was co-cultured in the fungal fermentation. The fungus, isolated from the surface of the brown alga Rosenvingea sp. collected in the Bahamas Islands, was identified as an undescribed member of the genus Pestalotia. The structure of 1, initially assigned with only modest confidence by combined spectral and chemical data, was confirmed by single-crystal X-ray analysis. Pestalone (1) exhibits moderate in vitro cytotoxicity in the National Cancer Institute's 60 human tumor cell line screen (mean GI(50) = 6.0 microM). More importantly, pestalone shows potent antibiotic activity against methicillin-resistant Staphylococcus aureus (MIC = 37 ng/mL) and vancomycin-resistant Enterococcus faecium (MIC = 78 ng/mL), indicating that pestalone should be evaluated in advanced models of infectious disease. PMID:11720529

  6. Transiently Produced Hypochlorite Is Responsible for the Irreversible Inhibition of Chlorite Dismutase

    PubMed Central

    2014-01-01

    Chlorite dismutases (Clds) are heme b-containing prokaryotic oxidoreductases that catalyze the reduction of chlorite to chloride with the concomitant release of molecular oxygen. Over time, they are irreversibly inactivated. To elucidate the mechanism of inactivation and investigate the role of the postulated intermediate hypochlorite, the pentameric chlorite dismutase of “Candidatus Nitrospira defluvii” (NdCld) and two variants (having the conserved distal arginine 173 exchanged with alanine and lysine) were recombinantly produced in Escherichia coli. Exchange of the distal arginine boosts the extent of irreversible inactivation. In the presence of the hypochlorite traps methionine, monochlorodimedone, and 2-[6-(4-aminophenoxy)-3-oxo-3H-xanthen-9-yl]benzoic acid, the extent of chlorite degradation and release of molecular oxygen is significantly increased, whereas heme bleaching and oxidative modifications of the protein are suppressed. Among other modifications, hypochlorite-mediated formation of chlorinated tyrosines is demonstrated by mass spectrometry. The data obtained were analyzed with respect to the proposed reaction mechanism for chlorite degradation and its dependence on pH. We discuss the role of distal Arg173 by keeping hypochlorite in the reaction sphere for O–O bond formation. PMID:24754261

  7. Constrained tibial vibration does not produce an anabolic bone response in adult mice.

    PubMed

    Christiansen, Blaine A; Kotiya, Akhilesh A; Silva, Matthew J

    2009-10-01

    Osteoporosis is characterized by low bone mass and increased fracture risk. High frequency, low-amplitude whole-body vibration (WBV) has been proposed as a treatment for osteoporosis because it can stimulate new bone formation and prevent trabecular bone loss. We developed constrained tibial vibration (CTV) as a method for controlled vibrational loading of the lower leg of a mouse. We first subjected mice to five weeks of daily CTV loading (0.5 G maximum acceleration) with loading parameters chosen to independently investigate the effects of strain magnitude, loading frequency, and cyclic acceleration on the adaptive response to vibration. We hypothesized that mice subjected to the highest magnitude of dynamic strain would have the largest bone formation response. We observed a slight, local benefit of CTV loading on trabecular bone, as BV/TV was 5.2% higher in the loaded vs. non-loaded tibia of mice loaded with the highest bone strain magnitude. However, despite these positive differences, we observed significantly lower measures of trabecular structure in both loaded and non-loaded tibias from CTV loaded mice compared to Sham and Baseline Control animals, indicating a negative systemic effect of CTV on trabecular bone. Based on this evidence, we conducted a follow-up study wherein mice were subjected to CTV or sham loading, and tibias were scanned at the beginning and end of the study period using in vivo microCT. Consistent with the findings of the first study, trabecular BV/TV in both tibias of CTV loaded and Sham mice was, on average, 36% and 31% lower on day 36 than day 0, respectively, compared to 20% lower in Age-Matched Controls over the same time period. Contrary to the first study, there were no differences between loaded and non-loaded tibias in CTV loaded mice, providing no evidence for a local benefit of CTV. In summary, 5 weeks of daily CTV loading of mice was, at best, weakly anabolic for trabecular bone in the proximal tibia, while daily handling

  8. Cardiovascular Disease and Diabetes

    MedlinePlus

    ... Blood Pressure Tools & Resources Stroke More Cardiovascular Disease & Diabetes Updated:Mar 23,2016 The following statistics speak ... disease. This content was last reviewed August 2015. Diabetes • Home • About Diabetes • Why Diabetes Matters Introduction Cardiovascular ...

  9. Rabbit tendon cells produce MMP-3 in response to fluid flow without significant calcium transients.

    PubMed

    Archambault, Joanne M; Elfervig-Wall, Michelle K; Tsuzaki, Mari; Herzog, Walter; Banes, Albert J

    2002-03-01

    Forces applied to tendon during movement cause cellular deformation, as well as fluid movement. The goal of this study was to test the hypothesis that rabbit tendon fibroblasts detect and respond to fluid-induced shear stress. Cells were isolated from the paratenon of the rabbit Achilles tendon and then subjected to fluid flow at 1 dyn/cm(2) for 6h in a specially designed multi-slide flow device. The application of fluid flow led to an increased expression of the collagenase-1 (MMP-1), stromelysin-1 (MMP-3), cyclooxygenase II (COX-2) and interleukin-1beta (IL-1beta) genes. The release of proMMP-3 into the medium exhibited a dose-response with the level of fluid shear stress. However, not all cells aligned in the direction of flow. In other experiments, the same cells were incubated with the calcium-reactive dye FURA-2 AM, then subjected to laminar fluid flow in a parallel plate flow chamber. The cells did not significantly increase intracellular calcium concentration when exposed to fluid shear stress levels of up to 25 dyn/cm(2). These results show that gene expression in rabbit tendon cells is sensitive to fluid flow, but that signal transduction is not dependent on intracellular calcium transients. The upregulation of the MMP-1, MMP-3 and COX-2 genes shows that fluid flow could be an important mechanical stimulus for tendon remodelling or injury. PMID:11858805

  10. Mutation of albedo and growth response produces oscillations in a spatial Daisyworld.

    PubMed

    Wood, A J; Ackland, G J; Lenton, T M

    2006-09-01

    We extended a two-dimensional cellular automaton (CA) Daisyworld to include mutation of optimal growth temperature as well as mutation of albedo. Thus, the organisms (daisies) can adapt to prevailing environmental conditions or evolve to alter their environment. We find the resulting system oscillates with a period of hundreds of daisy generations. Weaker and less regular oscillations exist in previous daisyworld models, but they become much stronger and more regular here with mutation in the growth response. Despite the existence of a particular combination of mean albedo and optimum individual growth temperature which maximises growth, we find that this global state is unstable with respect to mutations which lower absolute growth rate, but increase marginal growth rate. The resulting system oscillates with a period that is found to decrease with increasing death rate, and to increase with increasing heat diffusion and heat capacity. We speculate that the origin of this oscillation is a Hopf bifurcation, previously predicted in a zero-dimensional system. PMID:16581088

  11. Endothelial Ca2+-activated K+ channels in normal and impaired EDHF–dilator responses – relevance to cardiovascular pathologies and drug discovery

    PubMed Central

    Grgic, Ivica; Kaistha, Brajesh P; Hoyer, Joachim; Köhler, Ralf

    2009-01-01

    The arterial endothelium critically contributes to blood pressure control by releasing vasodilating autacoids such as nitric oxide, prostacyclin and a third factor or pathway termed ‘endothelium-derived hyperpolarizing factor’ (EDHF). The nature of EDHF and EDHF-signalling pathways is not fully understood yet. However, endothelial hyperpolarization mediated by the Ca2+-activated K+ channels (KCa) has been suggested to play a critical role in initializing EDHF–dilator responses in conduit and resistance-sized arteries of many species including humans. Endothelial KCa currents are mediated by the two KCa subtypes, intermediate-conductance KCa (KCa3.1) (also known as, a.k.a. IKCa) and small-conductance KCa type 3 (KCa2.3) (a.k.a. SKCa). In this review, we summarize current knowledge about endothelial KCa3.1 and KCa2.3 channels, their molecular and pharmacological properties and their specific roles in endothelial function and, particularly, in the EDHF–dilator response. In addition we focus on recent experimental evidences derived from KCa3.1- and/or KCa2.3-deficient mice that exhibit severe defects in EDHF signalling and elevated blood pressures, thus highlighting the importance of the KCa3.1/KCa2.3-EDHF–dilator system for blood pressure control. Moreover, we outline differential and overlapping roles of KCa3.1 and KCa2.3 for EDHF signalling as well as for nitric oxide synthesis and discuss recent evidence for a heterogeneous (sub) cellular distribution of KCa3.1 (at endothelial projections towards the smooth muscle) and KCa2.3 (at inter-endothelial borders and caveolae), which may explain their distinct roles for endothelial function. Finally, we summarize the interrelations of altered KCa3.1/KCa2.3 and EDHF system impairments with cardiovascular disease states such as hypertension, diabetes, dyslipidemia and atherosclerosis and discuss the therapeutic potential of KCa3.1/KCa2.3 openers as novel types of blood pressure-lowering drugs. British Journal of

  12. Infection and Cardiovascular Disease

    ClinicalTrials.gov

    2016-02-17

    Cardiovascular Diseases; Coronary Disease; Cerebrovascular Accident; Heart Diseases; Myocardial Infarction; Infection; Chlamydia Infections; Cytomegalovirus Infections; Helicobacter Infections; Atherosclerosis

  13. Optimization in Cardiovascular Modeling

    NASA Astrophysics Data System (ADS)

    Marsden, Alison L.

    2014-01-01

    Fluid mechanics plays a key role in the development, progression, and treatment of cardiovascular disease. Advances in imaging methods and patient-specific modeling now reveal increasingly detailed information about blood flow patterns in health and disease. Building on these tools, there is now an opportunity to couple blood flow simulation with optimization algorithms to improve the design of surgeries and devices, incorporating more information about the flow physics in the design process to augment current medical knowledge. In doing so, a major challenge is the need for efficient optimization tools that are appropriate for unsteady fluid mechanics problems, particularly for the optimization of complex patient-specific models in the presence of uncertainty. This article reviews the state of the art in optimization tools for virtual surgery, device design, and model parameter identification in cardiovascular flow and mechanobiology applications. In particular, it reviews trade-offs between traditional gradient-based methods and derivative-free approaches, as well as the need to incorporate uncertainties. Key future challenges are outlined, which extend to the incorporation of biological response and the customization of surgeries and devices for individual patients.

  14. Maternal nicotinic exposure produces a depressed hypoxic ventilatory response and subsequent death in postnatal rats.

    PubMed

    Zhuang, Jianguo; Zhao, Lei; Xu, Fadi

    2014-05-01

    In this study, we asked whether a "full term" prenatal nicotinic exposure (fPNE, 6 mg·kg(-1)·day(-1) nicotinic delivery) over the full gestation, compared to a traditional PNE (tPNE) over the last two-thirds of the gestation, caused a higher mortality following a remarkable depressed hypoxic ventilatory response (dHVR) independent of brain and pulmonary edema and change in serum corticosterone. P12-14 pups pretreated with tPNE, fPNE or their vehicle (tCtrl and fCtrl) were exposed to 5% O2 for up to 60 min followed by harvesting the brain and lungs or anesthetized to collect blood for detecting arterial blood pH/gases and serum cotinine and corticosterone levels. We found that fPNE had little effect on baseline VE and heart rate, but consistently induced a dHVR and prolonged apnea that were rarely observed after tPNE. The severity of the dHVR in PNE pups were closely correlated to an earlier appearance of lethal ventilatory arrest (the hypoxia-induced mortality). PNE did not induce brain and pulmonary edema, but significantly increased serum corticosterone levels similarly in tPNE and fPNE pups. Moreover, the accumulated nicotinic dose given to the individual was significantly higher in fPNE than tPNE pups, though there was no difference in serum cotinine levels and arterial blood pH/gases between the two groups. Our results suggest that nicotinic exposure at the early stage of gestation achieved by fPNE, rather than tPNE, is critical in generating the dHVR and subsequent death occurring independently of brain/pulmonary edema and changes in arterial blood pH/gases and serum corticosterone. PMID:24872357

  15. Maternal nicotinic exposure produces a depressed hypoxic ventilatory response and subsequent death in postnatal rats

    PubMed Central

    Zhuang, Jianguo; Zhao, Lei; Xu, Fadi

    2014-01-01

    Abstract In this study, we asked whether a “full term” prenatal nicotinic exposure (fPNE, 6 mg·kg−1·day−1 nicotinic delivery) over the full gestation, compared to a traditional PNE (tPNE) over the last two‐thirds of the gestation, caused a higher mortality following a remarkable depressed hypoxic ventilatory response (dHVR) independent of brain and pulmonary edema and change in serum corticosterone. P12‐14 pups pretreated with tPNE, fPNE or their vehicle (tCtrl and fCtrl) were exposed to 5% O2 for up to 60 min followed by harvesting the brain and lungs or anesthetized to collect blood for detecting arterial blood pH/gases and serum cotinine and corticosterone levels. We found that fPNE had little effect on baseline VE and heart rate, but consistently induced a dHVR and prolonged apnea that were rarely observed after tPNE. The severity of the dHVR in PNE pups were closely correlated to an earlier appearance of lethal ventilatory arrest (the hypoxia‐induced mortality). PNE did not induce brain and pulmonary edema, but significantly increased serum corticosterone levels similarly in tPNE and fPNE pups. Moreover, the accumulated nicotinic dose given to the individual was significantly higher in fPNE than tPNE pups, though there was no difference in serum cotinine levels and arterial blood pH/gases between the two groups. Our results suggest that nicotinic exposure at the early stage of gestation achieved by fPNE, rather than tPNE, is critical in generating the dHVR and subsequent death occurring independently of brain/pulmonary edema and changes in arterial blood pH/gases and serum corticosterone. PMID:24872357

  16. Producer and consumer responsibility for greenhouse gas emissions from agricultural production—a perspective from the Brazilian Amazon

    NASA Astrophysics Data System (ADS)

    Zaks, D. P. M.; Barford, C. C.; Ramankutty, N.; Foley, J. A.

    2009-10-01

    Greenhouse gases from the combination of land use change and agriculture are responsible for the largest share of global emissions, but are inadequately considered in the current set of international climate policies. Under the Kyoto protocol, emissions generated in the production of agricultural commodities are the responsibility of the producing country, introducing potential inequities if agricultural products are exported. This study quantifies the greenhouse gas emissions from the production of soybeans and beef in the Amazon basin of Brazil, a region where rates of both deforestation and agricultural exports are high. Integrating methods from land use science and life-cycle analysis, and accounting for producer-consumer responsibility, we allocate emissions between Brazil and importing countries with an emphasis on ultimately reducing the greenhouse gas impact of food production. The mechanisms used to distribute the carbon emissions over time allocate the bulk of emissions to the years directly after the land use change occurred, and gradually decrease the carbon allocation to the agricultural products. The carbon liability embodied in soybeans exported from the Amazon between 1990 and 2006 was 128 TgCO2e, while 120 TgCO2e were embodied in exported beef. An equivalent carbon liability was assigned to Brazil for that time period.

  17. Challenges of metal recycling and an international covenant as possible instrument of a globally extended producer responsibility.

    PubMed

    Wilts, Hennning; Bringezu, Stefan; Bleischwitz, Raimund; Lucas, Rainer; Wittmer, Dominic

    2011-09-01

    As illustrated by the case studies of end-of-life vehicles and waste electric and electronic equipment, the approach of an extended producer responsibility is undermined by the exports of used and waste products. This fact causes severe deficits regarding circular flows, especially of critical raw materials such as platinum group metals. With regard to global recycling there seems to be a responsibility gap which leads somehow to open ends of waste flows and a loss or down-cycling of potential secondary resources. Existing product-orientated extended producer responsibility (EPR) approaches with mass-based recycling quotas do not create adequate incentives to supply waste materials containing precious metals to a high-quality recycling and should be amended by aspects of a material stewardship. The paper analyses incentive effects on EPR for the mentioned product groups and metals, resulting from existing regulations in Germany. It develops a proposal for an international covenant on metal recycling as a policy instrument for a governance-oriented framework to initiate systemic innovations along the complete value chain taking into account product group- and resource group-specific aspects on different spatial levels. It aims at the effective implementation of a central idea of EPR, the transition of a waste regime still focusing on safe disposal towards a sustainable management of resources for the complete lifecycle of products. PMID:21771872

  18. Hemolysin-producing Listeria monocytogenes affects the immune response to T-cell-dependent and T-cell-independent antigens.

    PubMed Central

    Hage-Chahine, C M; Del Giudice, G; Lambert, P H; Pechere, J C

    1992-01-01

    A murine experimental infection with a hemolysin-producing (Hly+) strain of Listeria monocytogenes and a non-hemolysin-producing (Hly-) mutant was used as an in vivo model to evaluate the role of hemolysin production in the immune response. No antilisterial antibodies were detectable following sublethal infection with Hly+ bacteria, but consistent antilisterial immunoglobulin G (IgG) and IgM antibody production was observed following sublethal infection with the Hly- mutant. Hly+ but not Hly- L. monocytogenes induced transient inhibition of antibody response to Hly- bacteria and to unrelated T-cell-dependent (tetanus toxoid) and T-cell-independent (pneumococcal polysaccharide 3) antigens. Transient inhibition of the activation of an antigen-specific T-cell clone was also observed following Hly+ infection of antigen-presenting cells but not following Hly- infection. These results suggest that hemolysin production by L. monocytogenes is an important factor in modulating the immune response to T-cell-dependent and T-cell-independent antigens in infected individuals. Images PMID:1548067

  19. Trait anxiety mimics age-related cardiovascular autonomic modulation in young adults.

    PubMed

    Sanchez-Gonzalez, M A; Guzik, P; May, R W; Koutnik, A P; Hughes, R; Muniz, S; Kabbaj, M; Fincham, F D

    2015-04-01

    Anxiety produces maladaptive cardiovascular changes and accelerates biological aging. We evaluated cardiovascular reactivity in young and middle-aged individuals with varying anxiety scores to test the hypothesis that anxiety mimics cardiovascular aging by influencing cardiovascular autonomic modulation. The State-Trait Anxiety Inventory was used to classify healthy young individuals (20-29 years) into high (YHA, n=22;10 men) and low (YLA, n=21;10 men) anxiety, and to identify middle-aged individuals (50-60 years) with low anxiety (MLA, n=22;11 men). Heart rate, blood pressure (BP) and their variability (HRV and BPV, respectively) and baroreflex function were analyzed from beat-to-beat finger BP and electrocardiogram recordings collected during 5-min baseline, 6-min speech task (ST) and 3-min post ST recovery. Analyses of covariance showed significant differences (P<0.05) at baseline for HRV, BPV and barorelfex, and low-frequency power of systolic BP variability (LFSBP) was lower, whereas baroreflex and high frequency (HF) normalized units were higher in the YLA compared with YHA and MLA groups. Compared with YLA, YHA and MLA displayed attenuated vagal withdraw response (HF) to ST. BP and LFSBP responses to ST in YHA and MLA were higher compared with the YLA group. These findings suggest that anxiety could be linked to cardiovascular aging as it attenuates cardiac reactivity and exaggerates vascular responses to stress. PMID:25355009

  20. Cardiovascular lymphoscintigraphy

    SciTech Connect

    Castronuovo, J.J. Jr.; Lopez-Majano, V.; Flanigan, P.; Schuler, J.J.; Jonasson, O.

    1983-08-01

    The technique of lymphoscintigraphy when applied to the heart and blood vessels correlates well with results of anatomic investigations of arterial and cardiac lymphatic vessels reported in the literature. Five dogs and eight rabbits underwent lymphoscintigraphy of the heart and aorta, as well as the iliac, femoral, and tibial arteries. After surgical exposure, approximately 500 microCi of /sup 99m/Tc-labelled antimony sulfide was injected into the myocardium or the adventitial-medial plane of an artery. The colloid particle size of 4 to 12 m mu causes resorption and transport only via the lymphatic vessels. Twenty-one preparations were imaged from 2 to 48 hours after administration. This method provides a functional demonstration that the tibial and femoral arteries of both species are invested with lymphatics. The first echelon of lymph nodes which drain muscular arteries are imaged within 2 hours. Regional lymph nodes could not be seen to drain the aorta or iliac arteries. Anterior left ventricular myocardial injection in the dog showed a single cardiac lymph node. This drainage pattern has been described previously by other investigators. In the rabbit a similarly placed injection visualized a group of regional cardiac nodes. Ligation of the collecting ducts afferent to the cardiac node in the dog prevented removal of the isotope from the heart at 3, 6, and 9 hours. At 24 hours the liver and spleen were imaged, the radiocolloid gaining entrance to the blood vascular system presumably via myocardial lymphaticovenous anastomoses. Lymphoscintigraphy reflects physiologic processes such as lymph transport, filtration, and reticuloendothelial function. It defines regional patterns of cardiac and arterial lymph drainage. It can confirm experimentally produced impairment of lymph drainage from a defined area of tissue. Lymphoscintigraphy should be useful in the investigation of the significance of lymph drainage to diseases of the heart and blood vessels.

  1. [Cardiovascular safety of antidiabetics].

    PubMed

    Aline Roth, Pressl-Wenger; Jornayvaz, François R

    2016-06-01

    Type 2 diabetes is characterized by a high risk of micro- and macro-vascular complications. Cardiovascular diseases are the leading cause of death of diabetic patients. In this context, the search for molecules decreasing cardiovascular mortality makes sense. Until the EMPA-REG OUTCOME study published late 2015, showing a reduction of cardiovascular mortality of patients treated with empagliflozin, an SGLT2 inhibitor, there was no molecule known to decrease cardiovascular mortality. The purpose of this article is to review the various existing antidiabetic molecules and their impact (positive/neutral/negative) on cardiovascular mortality. PMID:27487675

  2. Fine Ambient Particulate and Ozone Co-Exposures in Durham, North Carolina: Influence of Season on Particle Chemistry and Cardiovascular Responses in Rats

    EPA Science Inventory

    Epidemiological studies have shown that the presence of one air pollutant modifies the cardiovascular health effects of another while controlled exposure studies in humans have documented synergistic effects of co-exposure to ambient particulate matter (PM) and ozone (O3) on bloo...

  3. Incidence and predictors of cardiovascular disease, chronic kidney disease, and diabetes in HIV/HCV-coinfected patients who achieved sustained virological response.

    PubMed

    Leone, S; Prosperi, M; Costarelli, S; Nasta, P; Maggiolo, F; Di Giambenedetto, S; Saracino, A; Di Pietro, M; Gori, A

    2016-09-01

    Data on the effects of sustained virologic response (SVR) to hepatitis C virus (HCV) therapy on the outcome of extrahepatic complications are scarce. We conducted this study to assess the impact of SVR on the occurrence of chronic kidney disease (CKD), diabetes mellitus (DM), and cardiovascular disease (CVD) in a cohort of human immunodeficiency virus (HIV)-infected patients. We analyzed coinfected HIV/HCV patients in the Management of Standardized Evaluation of Retroviral HIV Infection (MASTER) cohort. Only event-free patients with a serum HCV-RNA determination at baseline were included. Patients were divided into four groups: INF-exposed with SVR; INF-exposed without SVR; spontaneous HCV clearance; untreated viremic patients. We estimated the incidence of extrahepatic complications and employed Kaplan-Meier curves and Cox regression to assess the association of SVR/INF strata adjusted for a series of confounders. Data from 1676 patients were analyzed (20.29 % started an INF-based regimen). Overall, the incidence of CKD, DM, CVD, and death was 5.32 [95 % confidence interval (CI) 3.99-6.98], 10.13 (95 % CI 8.20-12.37), 6.79 (95 % CI 5.26-8.65), and 13.49 (95 % CI 11.29-16.0) per 1000 person-years of follow-up, respectively. In the Cox model for treated patients, SVR was not associated with a lower risk of CKD, DM, CVD, and death compared to non-SVR. Cirrhosis was significantly associated with a higher risk of CKD [hazard ratio (HR) 2.13; 95 % CI 1.06-4.31], DM (HR 3.48; 95 % CI 2.18-5.57), and death (HR 6.18; 95 % CI 4.1-9.31), but not of CVD (HR 1.14; 95 % CI 0.57-2.3). There are still many unknowns regarding the impact of SVR on the occurrence of extrahepatic complications in coinfected HIV/HCV patients. Further investigations are needed in order to elucidate the role of SVR as an independent prognostic factor for extrahepatic events. PMID:27272121

  4. Cardiovascular and neurohumoral postural responses and baroreceptor abnormalities during a course of adjunctive vasodilator therapy with felodipine for congestive heart failure.

    PubMed

    Kassis, E; Amtorp, O

    1987-06-01

    Studies in patients with congestive heart failure (CHF) have demonstrated an abnormal beta-adrenergic reflex vasodilation during orthostatic tilt. Baroreflex modulation of vascular resistance in patients with CHF was investigated during therapy with a vasoselective calcium antagonist, felodipine. Eight patients on conventional therapy for severe CHF were studied after a 3 week course of additional felodipine or placebo treatment under randomized, double-blind, and crossover conditions. Forearm subcutaneous vascular resistance (FSVR) was estimated with use of the local 133Xe washout. Aortic pulsatile stretch, expressed as the systolic distension in percent of diastolic diameter, was calculated from echocardiographic measurements of aortic root diameters. At 3 weeks, felodipine reduced the arterial pressure, systemic vascular resistance, and FSVR, preserved cardiac filling pressures and heart rate, and increased cardiac output, stroke volume, and aortic pulsatile stretch. Upright tilt (45 degrees) was used to study baroreflex-mediated cardiovascular responses. The unloading of cardiopulmonary baroreceptors during upright tilt was substantial and about equal during both treatment courses, but the pulse pressure was maintained during the placebo and decreased during the felodipine period. During tilt, the patients on placebo failed to increase heart rate and their FSVR, systemic vascular resistance, and arterial mean pressure were decreased, whereas during tilt after felodipine, heart rate and systemic vascular resistance increased to maintain arterial mean pressure and FSVR also tended to increase. Both the stroke volume and aortic pulsatile stretch increased during tilt in patients on placebo but they decreased in those on felodipine. The tilt caused increments in circulating norepinephrine and epinephrine levels during both treatment regimens. Regulation of FSVR during the sympathetic stimulation of orthostatic stress was further elucidated. Proximal neural blockade

  5. Association of cardiovascular response to an acute resistance training session with the ACE gene polymorphism in sedentary women: a randomized trial

    PubMed Central

    2013-01-01

    Background The aim of the present study was to verify the effects of an acute resistance training (RT) session and insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) on systolic (SBP), diastolic (DBP) and mean blood pressure (MBP), and heart rate (HR). Methods The sample consisted of 27 sedentary women (33.3 ± 8.2 yrs; 69.1 ± 13.8 kg; 1.57 ± 0.05 m; 27.6 ± 5.1 kg/m2) divided into two groups according to their polymorphism I/D (DD = 9; II + ID = 18). Volunteers underwent two experimental sessions: RT – an acute session performed with three sets at 60% of one-repetition maximum (1RM) interspersed with 1 minute rest interval between exercises and sets, and a control session (CON) in which they remained seated for 30 minutes in the laboratory. SBP, DBP, MBP and HR were measured before exercise and during one hour every 10 minutes after sessions, in the seated position. A two-way ANOVA for repeated measures with Tukey’s post hoc test was used for the intra and inter-group comparisons. Results There were no statistically significant differences on SBP, DBP and MBP after the experimental protocols, and no effect of ACE polymorphism (P > 0.05). However, comparing CON versus exercise effect size values (ES), homozygotic carriers of the allele D presented a drop in SBP which was considered moderate, while in allele I carriers it was small, 30 minutes after exercise. In MBP, homozygotic D carriers exhibited a large ES 20 minutes post-exercise. HR was higher at 10, 20 and 30 minutes after exercise as compared to pre-exercise only for carriers of the I allele (P < 0.05). Conclusions Therefore, an acute RT session reduces clinical BP. In addition to this; it seems that ACE polymorphism had some influence on cardiovascular response to exercise. Trial Registration RBR-6GDYVZ PMID:23305118

  6. GLP1- and GIP-producing cells rarely overlap and differ by bombesin receptor-2 expression and responsiveness.

    PubMed

    Svendsen, Berit; Pais, Ramona; Engelstoft, Maja S; Milev, Nikolay B; Richards, Paul; Christiansen, Charlotte B; Egerod, Kristoffer L; Jensen, Signe M; Habib, Abdella M; Gribble, Fiona M; Schwartz, Thue W; Reimann, Frank; Holst, Jens J

    2016-01-01

    The incretin hormones glucagon-like peptide-1 (GLP1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from intestinal endocrine cells, the so-called L- and K-cells. The cells are derived from a common precursor and are highly related, and co-expression of the two hormones in so-called L/K-cells has been reported. To investigate the relationship between the GLP1- and GIP-producing cells more closely, we generated a transgenic mouse model expressing a fluorescent marker in GIP-positive cells. In combination with a mouse strain with fluorescent GLP1 cells, we were able to estimate the overlap between the two cell types. Furthermore, we used primary cultured intestinal cells and isolated perfused mouse intestine to measure the secretion of GIP and GLP1 in response to different stimuli. Overlapping GLP1 and GIP cells were rare (∼5%). KCl, glucose and forskolin+IBMX increased the secretion of both GLP1 and GIP, whereas bombesin/neuromedin C only stimulated GLP1 secretion. Expression analysis showed high expression of the bombesin 2 receptor in GLP1 positive cells, but no expression in GIP-positive cells. These data indicate both expressional and functional differences between the GLP1-producing 'L-cell' and the GIP-producing 'K-cell'. PMID:26483393

  7. VeA Is Associated with the Response to Oxidative Stress in the Aflatoxin Producer Aspergillus flavus

    PubMed Central

    Baidya, Sachin; Duran, Rocio M.; Lohmar, J