Sample records for absolute muscle mass

  1. Predicting Functional Capacity From Measures of Muscle Mass in Postmenopausal Women.

    PubMed

    Orsatti, Fábio Lera; Nunes, Paulo Ricardo Prado; Souza, Aletéia de Paula; Martins, Fernanda Maria; de Oliveira, Anselmo Alves; Nomelini, Rosekeila Simões; Michelin, Márcia Antoniazi; Murta, Eddie Fernando Cândido

    2017-06-01

    Menopause increases body fat and decreases muscle mass and strength, which contribute to sarcopenia. The amount of appendicular muscle mass has been frequently used to diagnose sarcopenia. Different measures of appendicular muscle mass have been proposed. However, no studies have compared the most salient measure (appendicular muscle mass corrected by body fat) of the appendicular muscle mass to physical function in postmenopausal women. To examine the association of 3 different measurements of appendicular muscle mass (absolute, corrected by stature, and corrected by body fat) with physical function in postmenopausal women. Cross-sectional descriptive study. Outpatient geriatric and gynecological clinic. Forty-eight postmenopausal women with a mean age (standard deviation [SD]) of 62.1 ± 8.2 years, with mean (SD) length of menopause of 15.7 ± 9.8 years and mean (SD) body fat of 43.6% ± 9.8%. Not applicable. Appendicular muscle mass measure was measured with dual-energy x-ray absorptiometry. Physical function was measured by a functional capacity questionnaire, a short physical performance battery, and a 6 minute-walk test. Muscle quality (leg extensor strength to lower-body mineral-free lean mass ratio) and sum of z scores (sum of each physical function tests z score) were performed to provide a global index of physical function. The regression analysis showed that appendicular muscle mass corrected by body fat was the strongest predictor of physical function. Each increase in the standard deviation of appendicular muscle mass corrected by body fat was associated with a mean sum of z score increase of 59% (standard deviation), whereas each increase in absolute appendicular muscle mass and appendicular muscle mass corrected by stature were associated with a mean sum of z scores decrease of 23% and 36%, respectively. Muscle quality was associated with appendicular muscle mass corrected by body fat. These findings indicate that appendicular muscle mass corrected

  2. Obesity is associated with higher absolute tibiofemoral contact and muscle forces during gait with and without knee osteoarthritis.

    PubMed

    Harding, Graeme T; Dunbar, Michael J; Hubley-Kozey, Cheryl L; Stanish, William D; Astephen Wilson, Janie L

    2016-01-01

    Obesity is an important risk factor for knee osteoarthritis initiation and progression. However, it is unclear how obesity may directly affect the mechanical loading environment of the knee joint, initiating or progressing joint degeneration. The objective of this study was to investigate the interacting role of obesity and moderate knee osteoarthritis presence on tibiofemoral contact forces and muscle forces within the knee joint during walking gait. Three-dimensional gait analysis was performed on 80 asymptomatic participants and 115 individuals diagnosed with moderate knee osteoarthritis. Each group was divided into three body mass index categories: healthy weight (body mass index<25), overweight (25≤body mass index≤30), and obese (body mass index>30). Tibiofemoral anterior-posterior shear and compressive forces, as well as quadriceps, hamstrings and gastrocnemius muscle forces, were estimated based on a sagittal plane contact force model. Peak contact and muscle forces during gait were compared between groups, as well as the interaction between disease presence and body mass index category, using a two-factor analysis of variance. There were significant osteoarthritis effects in peak shear, gastrocnemius and quadriceps forces only when they were normalized to body mass, and there were significant BMI effects in peak shear, compression, gastrocnemius and hamstrings forces only in absolute, non-normalized forces. There was a significant interaction effect in peak quadriceps muscle forces, with higher forces in overweight and obese groups compared to asymptomatic healthy weight participants. Body mass index was associated with higher absolute tibiofemoral compression and shear forces as well as posterior muscle forces during gait, regardless of moderate osteoarthritis presence or absence. The differences found may contribute to accelerated joint damage with obesity, but with the osteoarthritic knees less able to accommodate the high loads. Copyright © 2015

  3. Relationships between central arterial stiffness, lean body mass, and absolute and relative strength in young and older men and women.

    PubMed

    Fahs, Christopher A; Thiebaud, Robert S; Rossow, Lindy M; Loenneke, Jeremy P; Bemben, Debra A; Bemben, Michael G

    2017-08-16

    Relationships between muscular strength and arterial stiffness as well as between muscle mass and arterial stiffness have been observed suggesting a link between the neuromuscular system and vascular health. However, the relationship between central arterial stiffness and absolute and relative strength along with muscle mass has not been investigated in both sexes across a broad age range. The purpose of this study was to examine the relationship between central arterial stiffness and absolute and relative strength as well as between central arterial stiffness and lean body mass (LBM) in men and women across a broad age range. LBM, central arterial stiffness and strength were measured on 36 men and 35 women between the ages of 18 and 75 years. Strength was measured on five machine resistance exercises and summed as one measure of overall strength (absolute strength). Relative strength was calculated as total strength divided by LBM (relative strength). Central arterial stiffness was inversely related to both absolute (r = -0·230; P = 0·029) and relative strength (r = -0·484; P < 0·001) but not LBM (r = 0·097; P = 0·213). The relationship between central arterial stiffness and relative strength was attenuated but still present when controlling for either age, per cent body fat, LBM or mean arterial pressure. These results suggest that, across a wide age range, the expression of relative muscular strength has a stronger relationship with central arterial stiffness compared to either LBM or absolute strength. This suggests that muscle function more than muscle mass may be coupled with vascular health. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  4. Quantification of Absolute Fat Mass by Magnetic Resonance Imaging: a Validation Study against Chemical Analysis

    PubMed Central

    Hu, Houchun H.; Li, Yan; Nagy, Tim R.; Goran, Michael I.; Nayak, Krishna S.

    2011-01-01

    Objective To develop a magnetic resonance imaging (MRI)-based approach for quantifying absolute fat mass in organs, muscles, and adipose tissues, and to validate its accuracy against reference chemical analysis (CA). Methods Chemical-shift imaging can accurately decompose water and fat signals from the acquired MRI data. A proton density fat fraction (PDFF) can be computed from the separated images, and reflects the relative fat content on a voxel-by-voxel basis. The PDFF is mathematically closely related to the fat mass fraction and can be converted to absolute fat mass in grams by multiplying by the voxel volume and the mass density of fat. In this validation study, 97 freshly excised and unique samples from four pigs, comprising of organs, muscles, and adipose and lean tissues were imaged by MRI and then analyzed independently by CA. Linear regression was used to assess correlation, agreement, and measurement differences between MRI and CA. Results Considering all 97 samples, a strong correlation and agreement was obtained between MRI and CA-derived fat mass (slope = 1.01, intercept = 1.99g, r2 = 0.98, p < 0.01). The mean difference d between MRI and CA was 2.17±3.40g. MRI did not exhibit any tendency to under or overestimate CA (p > 0.05). When considering samples from each pig separately, the results were (slope = 1.05, intercept = 1.11g, r2 = 0.98, d = 2.66±4.36g), (slope = 0.99, intercept = 2.33g, r2 = 0.99, d = 1.88±2.68g), (slope = 1.07, intercept = 1.52g, r2 = 0.96, d = 2.73±2.50g), and (slope=0.92, intercept=2.84g, r2 = 0.97, d = 1.18±3.90g), respectively. Conclusion Chemical-shift MRI and PDFF provides an accurate means of determining absolute fat mass in organs, muscles, and adipose and lean tissues. PMID:23204926

  5. Reliability and validity of quantifying absolute muscle hardness using ultrasound elastography.

    PubMed

    Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

    2012-01-01

    Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young's moduli of seven tissue-mimicking materials (in vitro; Young's modulus range, 20-80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young's modulus ratio of two reference materials, one hard and one soft (Young's moduli of 7 and 30 kPa, respectively), the Young's moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young's moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young's moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified.

  6. Reliability and Validity of Quantifying Absolute Muscle Hardness Using Ultrasound Elastography

    PubMed Central

    Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

    2012-01-01

    Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young’s moduli of seven tissue-mimicking materials (in vitro; Young’s modulus range, 20–80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young’s modulus ratio of two reference materials, one hard and one soft (Young’s moduli of 7 and 30 kPa, respectively), the Young’s moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young’s moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young’s moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified. PMID:23029231

  7. Skeletal muscle mass in human athletes: What is the upper limit?

    PubMed

    Abe, Takashi; Buckner, Samuel L; Dankel, Scott J; Jessee, Matthew B; Mattocks, Kevin T; Mouser, J Grant; Loenneke, Jeremy P

    2018-01-22

    To examine the amount of absolute and relative skeletal muscle mass (SM) in large sized athletes to investigate the potential upper limit of whole body muscle mass accumulation in the human body. Ninety-five large-sized male athletes and 48 recreationally active males (control) had muscle thickness measured by ultrasound at nine sites on the anterior and posterior aspects of the body. SM was estimated from an ultrasound-derived prediction equation. Body density was estimated by hydrostatic weighing technique, and then body fat percentage and fat-free mass (FFM) were calculated. We used the SM index and FFM index to adjust for the influence of standing height (ie, divided by height squared). Ten of the athletes had more than 100 kg of FFM, including the largest who had 120.2 kg, while seven of the athletes had more than 50 kg of SM, including the largest who had 59.3 kg. FFM index and SM index were higher in athletes compared to controls and the percentage differences between the two groups were 44% and 56%, respectively. The FFM index increased linearly up to 90 kg of body mass, and then the values leveled off in those of increasing body mass. Similarly, the SM index increased in a parabolic fashion reaching a plateau (approximately 17 kg/m 2 ) beyond 120 kg body mass. SM index may be a valuable indicator for determining skeletal muscle mass in athletes. A SM index of approximately 17 kg/m 2 may serve as the potential upper limit in humans. © 2018 Wiley Periodicals, Inc.

  8. Loss of REDD1 augments the rate of the overload-induced increase in muscle mass

    PubMed Central

    Liu, Chang; Steiner, Jennifer L.; Nader, Gustavo A.; Jefferson, Leonard S.; Kimball, Scot R.

    2016-01-01

    The overload-induced increase in muscle mass is accompanied by protein accretion; however, the initiating events are poorly understood. Regulated in Development and DNA Damage 1 (REDD1), a repressor of the mechanistic target of rapamycin in complex 1 (mTORC1), blunts the elevation in protein synthesis induced by acute muscle contractions. Therefore, this study was designed to determine whether REDD1 alters the rate of the overload-induced increase in muscle mass. Wild-type (WT) and REDD1-null mice underwent unilateral functional overload (OV) of the plantaris, while the contralateral sham leg served as a control. After 3 and 5 days of OV, puromycin incorporation was used as a measurement of protein synthesis. The percent increase in plantaris wet weight and protein content was greater in REDD1-null mice after 3, 5, and 10 days OV. The overload-stimulated rate of protein synthesis in the plantaris was similar between genotypes after 3 days OV, but translational capacity was lower in REDD1-null mice, indicating elevated translational efficiency. This was likely due to elevated absolute mTORC1 signaling [phosphorylation of p70S6K1 (Thr-389) and 4E-BP1 (Ser-65)]. By 5 days of OV, the rate of protein synthesis in REDD1-null mice was lower than WT mice with no difference in absolute mTORC1 signaling. Additionally, markers of autophagy (LC3II/I ratio and p62 protein) were decreased to a greater absolute extent after 3 days OV in REDD1-null mice. These data suggest that loss of REDD1 augments the rate of the OV-induced increase in muscle mass by altering multiple protein balance pathways. PMID:27465734

  9. Sleep, Muscle Mass and Muscle Function in Older People.

    PubMed

    Buchmann, Nikolaus; Spira, Dominik; Norman, Kristina; Demuth, Ilja; Eckardt, Rahel; Steinhagen-Thiessen, Elisabeth

    2016-04-15

    Loss of muscle mass, particularly in old age, can restrict mobility and physical function. Sleep is thought to play a key role in the maintenance of muscle mass; sleep disturbances have a prevalence of 6-30% in Germany. In this study, based on data from the Berlin Aging Study II (BASE-II), we analyze the relationship between sleep efficiency and quality on the one hand, and muscle mass and muscle function on the other. We analyzed cross-sectional data from 1196 subjects (52.5% women; 68 ± 4 years). Sleep behavior was assessed with questions from the Pittsburgh Sleep Quality Index; appendicular lean mass (ALM) with dual x-ray absorp - tiometry; and muscle function with a measure of grip strength and with questionnaires about physical activity and impairment of physical activities. Low muscle mass was determined from the ALM corrected by the body-mass index (BMI), i.e., from the ratio ALM/BMI. 19.1% of the women and 13.4% of the men reported poor sleep quality. Men whose ALM/BMI ratio was below the cutoff value for low muscle mass more frequently reported very poor sleep efficiency (9.1% , versus 4.8% in women; p<0.002). The adjusted odds ratio for low muscle mass was 2.8 for men with poor sleep quality (95% confidence interval: [1.1; 6.7]) and 4.3 for men with poor sleep efficiency [1.2; 15.1]. In women, there was no statistically significant association between sleep quality and efficiency on the one hand and ALM/BMI values below cutoff on the other, but poor sleep quality was found to be associated with reduced grip strength (16.25 kg ± 2.33 kg versus 15.67 kg ± 2.38 kg; p = 0.009) and low appendicular lean mass (ALM: 16.25 kg ± 2.33 kg versus 15.67 kg ± 2.38 kg; p = 0.016). These findings support the hypothesis of a link between sleep and muscle mass. The dependence of muscle mass on sleep behavior needs to be investigated in longitudinal studies.

  10. Absolute neutrino mass measurements

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

    Wolf, Joachim

    2011-10-06

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments inmore » Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.« less

  11. Muscle Strength and Muscle Mass in Older Patients during Hospitalization: The EMPOWER Study

    PubMed Central

    Van Ancum, Jeanine M.; Scheerman, Kira; Pierik, Vincent D.; Numans, Siger T.; Verlaan, Sjors; Smeenk, Hanne E.; Slee-Valentijn, Monique; Kruizinga, Roeliene C.; Meskers, Carel G.M.; Maier, Andrea B.

    2017-01-01

    Background Low muscle strength and muscle mass are associated with an increased length of hospital stay and higher mortality rate in inpatients. To what extent hospitalization affects muscle strength and muscle mass is unclear. Objective We aimed to assess muscle strength and muscle mass at admission and during hospitalization in older patients and its relation with being at risk of geriatric conditions. Methods The EMPOWER study included patients aged 70 years and older, admitted to 4 wards of the VU University Medical Center in the Netherlands between April and December 2015. At admission, patients were screened for being at risk of 4 geriatric conditions: delirium, falls, malnutrition, and functional disability. At admission and at discharge, muscle strength and muscle mass were assessed. Results A total of 373 patients (mean age, standard deviation [SD]: 79.6, 6.38 years) were included at admission, and 224 patients (mean age, SD: 80.1, 6.32 years) at discharge. At admission, lower muscle strength in both female and male patients and low muscle mass in male patients were associated with being at risk of a higher cumulative number of geriatric conditions. Muscle strength increased during hospitalization, but no change in muscle mass was observed. Changes in muscle measures were not associated with being at risk of geriatric conditions. Discussion Older patients with lower muscle strength and muscle mass at admission were at risk of a higher cumulative number of geriatric conditions. However, being at risk of geriatric conditions did not forecast further decrease in muscle strength and muscle mass during hospitalization PMID:28817825

  12. Muscle Strength and Muscle Mass in Older Patients during Hospitalization: The EMPOWER Study.

    PubMed

    Van Ancum, Jeanine M; Scheerman, Kira; Pierik, Vincent D; Numans, Siger T; Verlaan, Sjors; Smeenk, Hanne E; Slee-Valentijn, Monique; Kruizinga, Roeliene C; Meskers, Carel G M; Maier, Andrea B

    2017-01-01

    Low muscle strength and muscle mass are associated with an increased length of hospital stay and higher mortality rate in inpatients. To what extent hospitalization affects muscle strength and muscle mass is unclear. We aimed to assess muscle strength and muscle mass at admission and during hospitalization in older patients and its relation with being at risk of geriatric conditions. The EMPOWER study included patients aged 70 years and older, admitted to 4 wards of the VU University Medical Center in the Netherlands between April and December 2015. At admission, patients were screened for being at risk of 4 geriatric conditions: delirium, falls, malnutrition, and functional disability. At admission and at discharge, muscle strength and muscle mass were assessed. A total of 373 patients (mean age, standard deviation [SD]: 79.6, 6.38 years) were included at admission, and 224 patients (mean age, SD: 80.1, 6.32 years) at discharge. At admission, lower muscle strength in both female and male patients and low muscle mass in male patients were associated with being at risk of a higher cumulative number of geriatric conditions. Muscle strength increased during hospitalization, but no change in muscle mass was observed. Changes in muscle measures were not associated with being at risk of geriatric conditions. Older patients with lower muscle strength and muscle mass at admission were at risk of a higher cumulative number of geriatric conditions. However, being at risk of geriatric conditions did not forecast further decrease in muscle strength and muscle mass during hospitalization. © 2017 The Author(s) Published by S. Karger AG, Basel.

  13. Standardization approaches in absolute quantitative proteomics with mass spectrometry.

    PubMed

    Calderón-Celis, Francisco; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2017-07-31

    Mass spectrometry-based approaches have enabled important breakthroughs in quantitative proteomics in the last decades. This development is reflected in the better quantitative assessment of protein levels as well as to understand post-translational modifications and protein complexes and networks. Nowadays, the focus of quantitative proteomics shifted from the relative determination of proteins (ie, differential expression between two or more cellular states) to absolute quantity determination, required for a more-thorough characterization of biological models and comprehension of the proteome dynamism, as well as for the search and validation of novel protein biomarkers. However, the physico-chemical environment of the analyte species affects strongly the ionization efficiency in most mass spectrometry (MS) types, which thereby require the use of specially designed standardization approaches to provide absolute quantifications. Most common of such approaches nowadays include (i) the use of stable isotope-labeled peptide standards, isotopologues to the target proteotypic peptides expected after tryptic digestion of the target protein; (ii) use of stable isotope-labeled protein standards to compensate for sample preparation, sample loss, and proteolysis steps; (iii) isobaric reagents, which after fragmentation in the MS/MS analysis provide a final detectable mass shift, can be used to tag both analyte and standard samples; (iv) label-free approaches in which the absolute quantitative data are not obtained through the use of any kind of labeling, but from computational normalization of the raw data and adequate standards; (v) elemental mass spectrometry-based workflows able to provide directly absolute quantification of peptides/proteins that contain an ICP-detectable element. A critical insight from the Analytical Chemistry perspective of the different standardization approaches and their combinations used so far for absolute quantitative MS-based (molecular and

  14. Lower Cognitive Function in Older Patients with Lower Muscle Strength and Muscle Mass.

    PubMed

    van Dam, Romee; Van Ancum, Jeanine M; Verlaan, Sjors; Scheerman, Kira; Meskers, Carel G M; Maier, Andrea B

    2018-06-18

    Low muscle strength and muscle mass are associated with adverse outcomes in older hospitalized patients. The aim of this study was to assess the association between cognitive functioning and muscle strength and muscle mass in hospitalized older patients. This prospective inception cohort included 378 patients aged 70 years or older. At admission patients were assessed for cognitive functioning by use of the Six-Item Cognitive Impairment Test (6-CIT). Muscle strength and muscle mass were assessed using handheld dynamometry and segmental multifrequency bioelectrical impedance analysis, within 48 h after admission and on day 7, or earlier on the day of discharge. The data of 371 patients (mean age ± standard deviation 80.1 ± 6.4 years, 49.3% female) were available for analyses. The median (interquartile range) 6-CIT score was 4 (0-8) points. At admission, lower cognitive functioning was associated with lower muscle strength, lower skeletal muscle mass (SMM), lower appendicular lean mass, and lower SMM index. Cognitive functioning was not associated with change in muscle strength and muscle mass during hospitalization. This study further strengthens evidence for an association between lower cognitive functioning and lower muscle strength and muscle mass, but without a further decline during hospitalization. © 2018 The Author(s) Published by S. Karger AG, Basel.

  15. Reduced Appendicular Lean Body Mass, Muscle Strength, and Size of Type II Muscle Fibers in Patients with Spondyloarthritis versus Healthy Controls: A Cross-Sectional Study.

    PubMed

    Røren Nordén, Kristine; Dagfinrud, Hanne; Løvstad, Amund; Raastad, Truls

    Introduction . The purpose of this study was to investigate body composition, muscle function, and muscle morphology in patients with spondyloarthritis (SpA). Methods . Ten male SpA patients (mean ± SD age 39 ± 4.1 years) were compared with ten healthy controls matched for sex, age, body mass index, and self-reported level of physical exercise. Body composition was measured by dual energy X-ray absorptiometry. Musculus quadriceps femoris (QF) strength was assessed by maximal isometric contractions prior to test of muscular endurance. Magnetic resonance imaging of QF was used to measure muscle size and calculate specific muscle strength. Percutaneous needle biopsy samples were taken from m. vastus lateralis . Results . SpA patients presented with significantly lower appendicular lean body mass (LBM) ( p = 0.02), but there was no difference in bone mineral density, fat mass, or total LBM. Absolute QF strength was significantly lower in SpA patients ( p = 0.03) with a parallel trend for specific strength ( p = 0.08). Biopsy samples from the SpA patients revealed significantly smaller cross-sectional area (CSA) of type II muscle fibers ( p = 0.04), but no difference in CSA type I fibers. Conclusions . Results indicate that the presence of SpA disease is associated with reduced appendicular LBM, muscle strength, and type II fiber CSA.

  16. Comparison of skeletal muscle mass to fat-free mass ratios among different ethnic groups.

    PubMed

    Abe, T; Bemben, M G; Kondo, M; Kawakami, Y; Fukunaga, T

    2012-01-01

    Asians seem to have less skeletal muscle mass (SMM) than other ethnic groups, but it is not clear whether relative SMM, i.e., SMM / height square or SMM to fat-free mass (FFM) ratio, differs among different ethnic groups at the same level of body mass index (BMI). To compare the SMM to fat-free mass (FFM) ratio as well as anthropometric variables and body composition among 3 ethnic groups. Three hundred thirty-nine Japanese, 343 Brazilian, and 183 German men and women were recruited for this cross-sectional study. Muscle thickness (MTH) and subcutaneous fat thickness (FTH) were measured by ultrasound at nine sites on the anterior and posterior aspects of the body. FTH was used to estimate the body density, from which fat mass and fat-free mass (FFM) was calculated by using Brozek equation. Total SMM was estimated from ultrasound-derived prediction equations. Percentage body fat was similar among the ethnic groups in men, while Brazilians were higher than Japanese in women. In German men and women, absolute SMM and FFM were higher than in their Japanese and Brazilians counterparts. SMM index and SMM:FFM ratios were similar among the ethnic groups in women, excluding SMM:FFM ratio in Brazilian. In men, however, these relative values (SMM index and SMM:FFM ratio) were still higher in Germans. After adjusting for age and BMI, the SMM index and SMM:FFM ratios were lower in Brazilian men and women compared with the other two ethnic groups, while the SMM index and SMM:FFM ratios were similar in Japanese and German men and women, excluding SMM:FFM ratio in women. Our results suggest that relative SMM is not lower in Asian populations compared with European populations after adjusted by age and BMI.

  17. Cut-off Points for Muscle Mass - Not Grip Strength or Gait Speed - Determine Variations in Sarcopenia Prevalence.

    PubMed

    Masanés, F; Rojano I Luque, X; Salvà, A; Serra-Rexach, J A; Artaza, I; Formiga, F; Cuesta, F; López Soto, A; Ruiz, D; Cruz-Jentoft, A J

    2017-01-01

    The European Working Group on Sarcopenia in Older People (EWGSOP) has proposed different methods and cut-off points for the three parameters that define sarcopenia: muscle mass, muscle strength and physical performance. Although this facilitates clinical practice, it limits comparability between studies and leads to wide differences in published prevalence rates. The aim of this study was to assess how changes in cut-off points for muscle mass, gait speed and grip strength affected sarcopenia prevalence according to EWGSOP criteria. Cross-sectional analysis of elderly individuals recruited from outpatient clinics (n=298) and nursing homes (n=276). We measured muscle mass, grip strength and gait speed and assessed how changes in cut-off points changed sarcopenia prevalence in both populations. An increase from 5.45 kg/m2 to 6.68 kg/m2 in the muscle mass index for female outpatients and nursing-home residents increased sarcopenia prevalence from 4% to 23% and from 9% to 47%, respectively; for men, for an increase from 7.25 kg/m2 to 8.87 kg/m2, the corresponding increases were from 1% to 22% and from 6% to 41%, respectively. Changes in gait speed and grip strength had a limited impact on sarcopenia prevalence. The cut-off points used for muscle mass affect the reported prevalence rates for sarcopenia and, in turn, affect comparability between studies. The main factors influencing the magnitude of the change are muscle mass index distribution in the population and the absolute value of the cut-off points: the same difference between two references (e.g., 7.5 kg/m2 to 7.75 kg/m2 or 7.75 kg/m2 to 8 kg/m2) may produce different changes in prevalence. Changes in cut-off points for gait speed and grip strength had a limited impact on sarcopenia prevalence and on study comparability.

  18. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    NASA Astrophysics Data System (ADS)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  19. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    PubMed Central

    Gurley, Katelyn; Shang, Yu

    2012-01-01

    Abstract. This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (V˙O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and V˙O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (rV˙O2). The rBF and rV˙O2 signals were calibrated with absolute baseline BF and V˙O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology. PMID:22894482

  20. Poor vitamin D status is prospectively associated with greater muscle mass loss in middle-aged and elderly Chinese individuals.

    PubMed

    Liu, Gang; Lu, Ling; Sun, Qi; Ye, Xingwang; Sun, Liang; Liu, Xin; Zong, Geng; Jin, Qianlu; Li, Huaixing; Lin, Xu

    2014-10-01

    Poor vitamin D status can increase age-related muscle mass loss. However, existing prospective evidence is limited and controversial. This study aimed to investigate the association of plasma 25-hydroxyvitamin D [25(OH)D] with muscle mass loss in middle-aged and elderly Chinese individuals over 6 years. We conducted a prospective cohort study. This community-based study included 568 men and women aged 50 to 70 years at baseline. Baseline plasma concentrations of 25(OH)D and biomarkers of liver and kidney functions and inflammation were measured. Body composition was assessed at baseline and 6-year follow-up by dual-energy x-ray absorptiometry. Appendicular skeletal muscle mass (ASMM) and trunk lean mass were calculated and total body lean mass was defined as an overall measure of total nonfat and nonbone tissues. Descriptive statistics and multiple linear regression were applied. The 6-year loss of ASMM was 1.14 kg (5.3%) in men and 0.47 kg (3.1%) in women (all P values <0.001). Compared with the highest 25(OH)D tertile, participants in the lowest tertile had significantly more absolute loss of ASMM (-1.21 vs -1.00 kg; P for trend=0.024) after multivariate adjustments for conventional confounders, as well as protein intake. The association persisted after additional adjustment of bone mineral density and inflammatory markers (P for trend=0.017). No significant associations were detected between 25(OH)D and absolute loss of trunk lean mass or total body lean mass. Lower 25(OH)D concentrations were prospectively associated with greater ASMM loss in middle-aged and elderly Chinese individuals independent of bone mineral density, inflammation, diet, and other risk factors. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  1. Low Muscle Mass and Breast Cancer Survival

    Cancer.gov

    In a new study, researchers compared the risk of death for women with breast cancer who had low skeletal muscle mass, or sarcopenia, at diagnosis and women who had adequate muscle mass. Learn what they found and what it might mean for patients in this Cancer Currents blog post.

  2. A Dietary Supplementation with Leucine and Antioxidants Is Capable to Accelerate Muscle Mass Recovery after Immobilization in Adult Rats

    PubMed Central

    Savary-Auzeloux, Isabelle; Magne, Hugues; Migné, Carole; Oberli, Marion; Breuillé, Denis; Faure, Magali; Vidal, Karine; Perrot, Marie; Rémond, Didier; Combaret, Lydie; Dardevet, Dominique

    2013-01-01

    Prolonged inactivity induces muscle loss due to an activation of proteolysis and decreased protein synthesis; the latter is also involved in the recovery of muscle mass. The aim of the present work was to explore the evolution of muscle mass and protein metabolism during immobilization and recovery and assess the effect of a nutritional strategy for counteracting muscle loss and facilitating recovery. Adult rats (6–8 months) were subjected to unilateral hindlimb casting for 8 days (I0–I8) and then permitted to recover for 10 to 40 days (R10–R40). They were fed a Control or Experimental diet supplemented with antioxidants/polyphenols (AOX) (I0 to I8), AOX and leucine (AOX + LEU) (I8 to R15) and LEU alone (R15 to R40). Muscle mass, absolute protein synthesis rate and proteasome activities were measured in gastrocnemius muscle in casted and non-casted legs in post prandial (PP) and post absorptive (PA) states at each time point. Immobilized gastrocnemius protein content was similarly reduced (-37%) in both diets compared to the non-casted leg. Muscle mass recovery was accelerated by the AOX and LEU supplementation (+6% AOX+LEU vs. Control, P<0.05 at R40) due to a higher protein synthesis both in PA and PP states (+23% and 31% respectively, Experimental vs. Control diets, P<0.05, R40) without difference in trypsin- and chymotrypsin-like activities between diets. Thus, this nutritional supplementation accelerated the recovery of muscle mass via a stimulation of protein synthesis throughout the entire day (in the PP and PA states) and could be a promising strategy to be tested during recovery from bed rest in humans. PMID:24312309

  3. Integrated expression analysis of muscle hypertrophy identifies Asb2 as a negative regulator of muscle mass

    PubMed Central

    Davey, Jonathan R.; Watt, Kevin I.; Parker, Benjamin L.; Chaudhuri, Rima; Ryall, James G.; Cunningham, Louise; Qian, Hongwei; Sartorelli, Vittorio; Chamberlain, Jeffrey; James, David E.

    2016-01-01

    The transforming growth factor-β (TGF-β) signaling network is a critical regulator of skeletal muscle mass and function and, thus, is an attractive therapeutic target for combating muscle disease, but the underlying mechanisms of action remain undetermined. We report that follistatin-based interventions (which modulate TGF-β network activity) can promote muscle hypertrophy that ameliorates aging-associated muscle wasting. However, the muscles of old sarcopenic mice demonstrate reduced response to follistatin compared with healthy young-adult musculature. Quantitative proteomic and transcriptomic analyses of young-adult muscles identified a transcription/translation signature elicited by follistatin exposure, which included repression of ankyrin repeat and SOCS box protein 2 (Asb2). Increasing expression of ASB2 reduced muscle mass, thereby demonstrating that Asb2 is a TGF-β network–responsive negative regulator of muscle mass. In contrast to young-adult muscles, sarcopenic muscles do not exhibit reduced ASB2 abundance with follistatin exposure. Moreover, preventing repression of ASB2 in young-adult muscles diminished follistatin-induced muscle hypertrophy. These findings provide insight into the program of transcription and translation events governing follistatin-mediated adaptation of skeletal muscle attributes and identify Asb2 as a regulator of muscle mass implicated in the potential mechanistic dysfunction between follistatin-mediated muscle growth in young and old muscles. PMID:27182554

  4. Chronic exercise preserves lean muscle mass in masters athletes.

    PubMed

    Wroblewski, Andrew P; Amati, Francesca; Smiley, Mark A; Goodpaster, Bret; Wright, Vonda

    2011-09-01

    Aging is commonly associated with a loss of muscle mass and strength, resulting in falls, functional decline, and the subjective feeling of weakness. Exercise modulates the morbidities of muscle aging. Most studies, however, have examined muscle-loss changes in sedentary aging adults. This leaves the question of whether the changes that are commonly associated with muscle aging reflect the true physiology of muscle aging or whether they reflect disuse atrophy. This study evaluated whether high levels of chronic exercise prevents the loss of lean muscle mass and strength experienced in sedentary aging adults. A cross-section of 40 high-level recreational athletes ("masters athletes") who were aged 40 to 81 years and trained 4 to 5 times per week underwent tests of health/activity, body composition, quadriceps peak torque (PT), and magnetic resonance imaging of bilateral quadriceps. Mid-thigh muscle area, quadriceps area (QA), subcutaneous adipose tissue, and intramuscular adipose tissue were quantified in magnetic resonance imaging using medical image processing, analysis, and visualization software. One-way analysis of variance was used to examine age group differences. Relationships were evaluated using Spearman correlations. Mid-thigh muscle area (P = 0.31) and lean mass (P = 0.15) did not increase with age and were significantly related to retention of mid-thigh muscle area (P < 0.0001). This occurred despite an increase in total body fat percentage (P = 0.003) with age. Mid-thigh muscle area (P = 0.12), QA (P = 0.17), and quadriceps PT did not decline with age. Specific strength (strength per QA) did not decline significantly with age (P = 0.06). As muscle area increased, PT increased significantly (P = 0.008). There was not a significant relationship between intramuscular adipose tissue (P = 0.71) or lean mass (P = 0.4) and PT. This study contradicts the common observation that muscle mass and strength decline as a function of aging alone. Instead, these

  5. Relationship between muscle mass and physical performance: is it the same in older adults with weak muscle strength?

    PubMed

    Kim, Kyoung-Eun; Jang, Soong-Nang; Lim, Soo; Park, Young Joo; Paik, Nam-Jong; Kim, Ki Woong; Jang, Hak Chul; Lim, Jae-Young

    2012-11-01

    the relationship between muscle mass and physical performance has not been consistent among studies. to clarify the relationship between muscle mass and physical performance in older adults with weak muscle strength. cross-sectional analysis using the baseline data of 542 older men and women from the Korean Longitudinal Study on Health and Aging. dual X-ray absorptiometry, isokinetic dynamometer and the Short Physical Performance Battery (SPPB) were performed. Two muscle mass parameters, appendicular skeletal mass divided by weight (ASM/Wt) and by height squared (ASM/Ht(2)), were measured. We divided the participants into a lower-quartile (L25) group and an upper-three-quartiles (H75) group based on the knee-extensor peak torque. Correlation analysis and logistic regression models were used to assess the association between muscle mass and low physical performance, defined as SPPB scores <9, after controlling for confounders. in the L25 group, no correlation between mass and SPPB was detected, whereas the correlation between peak torque and SPPB was significant and higher than that in the H75 group. Results from the logistic models also showed no association between muscle mass and SPPB in the L25 group, whereas muscle mass was associated with SPPB in the H75 group. muscle mass was not associated with physical performance in weak older adults. Measures of muscle strength may be of greater clinical importance in weak older adults than is muscle mass per se.

  6. Absolute quantification of carnosine in human calf muscle by proton magnetic resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Özdemir, Mahir S.; Reyngoudt, Harmen; DeDeene, Yves; Sazak, Hakan S.; Fieremans, Els; Delputte, Steven; D'Asseler, Yves; Derave, Wim; Lemahieu, Ignace; Achten, Eric

    2007-12-01

    Carnosine has been shown to be present in the skeletal muscle and in the brain of a variety of animals and humans. Despite the various physiological functions assigned to this metabolite, its exact role remains unclear. It has been suggested that carnosine plays a role in buffering in the intracellular physiological pHi range in skeletal muscle as a result of accepting hydrogen ions released in the development of fatigue during intensive exercise. It is thus postulated that the concentration of carnosine is an indicator for the extent of the buffering capacity. However, the determination of the concentration of this metabolite has only been performed by means of muscle biopsy, which is an invasive procedure. In this paper, we utilized proton magnetic resonance spectroscopy (1H MRS) in order to perform absolute quantification of carnosine in vivo non-invasively. The method was verified by phantom experiments and in vivo measurements in the calf muscles of athletes and untrained volunteers. The measured mean concentrations in the soleus and the gastrocnemius muscles were found to be 2.81 ± 0.57/4.8 ± 1.59 mM (mean ± SD) for athletes and 2.58 ± 0.65/3.3 ± 0.32 mM for untrained volunteers, respectively. These values are in agreement with previously reported biopsy-based results. Our results suggest that 1H MRS can provide an alternative method for non-invasively determining carnosine concentration in human calf muscle in vivo.

  7. Fingerprints of flower absolutes using supercritical fluid chromatography hyphenated with high resolution mass spectrometry.

    PubMed

    Santerre, Cyrille; Vallet, Nadine; Touboul, David

    2018-06-02

    Supercritical fluid chromatography hyphenated with high resolution mass spectrometry (SFC-HRMS) was developed for fingerprint analysis of different flower absolutes commonly used in cosmetics field, especially in perfumes. Supercritical fluid chromatography-atmospheric pressure photoionization-high resolution mass spectrometry (SFC-APPI-HRMS) technique was employed to identify the components of the fingerprint. The samples were separated with a porous graphitic carbon (PGC) Hypercarb™ column (100 mm × 2.1 mm, 3 μm) by gradient elution using supercritical CO 2 and ethanol (0.0-20.0 min (2-30% B), 20.0-25.0 min (30% B), 25.0-26.0 min (30-2% B) and 26.0-30.0 min (2% B)) as mobile phase at a flow rate of 1.5 mL/min. In order to compare the SFC fingerprints between five different flower absolutes: Jasminum grandiflorum absolutes, Jasminum sambac absolutes, Narcissus jonquilla absolutes, Narcissus poeticus absolutes, Lavandula angustifolia absolutes from different suppliers and batches, the chemometric procedure including principal component analysis (PCA) was applied to classify the samples according to their genus and their species. Consistent results were obtained to show that samples could be successfully discriminated. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Hypertrophy Stimulation at the Onset of Type I Diabetes Maintains the Soleus but Not the EDL Muscle Mass in Wistar Rats

    PubMed Central

    Fortes, Marco A. S.; Scervino, Maria V. M.; Marzuca-Nassr, Gabriel N.; Vitzel, Kaio F.; da Justa Pinheiro, Carlos H.; Curi, Rui

    2017-01-01

    Diabetes mellitus induces a reduction in skeletal muscle mass and strength. Strength training is prescribed as part of treatment since it improves glycemic control and promotes increase of skeletal muscle mass. The mechanisms involved in overload-induced muscle hypertrophy elicited at the establishment of the type I diabetic state was investigated in Wistar rats. The purpose was to examine whether the overload-induced hypertrophy can counteract the hypotrophy associated to the diabetic state. The experiments were performed in oxidative (soleus) or glycolytic (EDL) muscles. PI3K/Akt/mTOR protein synthesis pathway was evaluated 7 days after overload-induced hypertrophy of soleus and of EDL muscles. The mRNA expression of genes associated with different signaling pathways that control muscle hypertrophy was also evaluated: mechanotransduction (FAK), Wnt/β-catenin, myostatin, and follistatin. The soleus and EDL muscles when submitted to overload had similar hypertrophic responses in control and diabetic animals. The increase of absolute and specific twitch and tetanic forces had the same magnitude as muscle hypertrophic response. Hypertrophy of the EDL muscle from diabetic animals mostly involved mechanical loading-stimulated PI3K/Akt/mTOR pathway besides the reduced activation of AMP-activated protein kinase (AMPK) and decrease of myostatin expression. Hypertrophy was more pronounced in the soleus muscle of diabetic animals due to a more potent activation of rpS6 and increased mRNA expression of insulin-like growth factor-1 (IGF-1), mechano-growth factor (MGF) and follistatin, and decrease of myostatin, MuRF-1 and atrogin-1 contents. The signaling changes enabled the soleus muscle mass and force of the diabetic rats to reach the values of the control group. PMID:29123487

  9. Licorice flavonoid oil enhances muscle mass in KK-Ay mice.

    PubMed

    Yoshioka, Yasukiyo; Yamashita, Yoko; Kishida, Hideyuki; Nakagawa, Kaku; Ashida, Hitoshi

    2018-07-15

    Muscle mass is regulated by the balance between the synthesis and degradation of muscle proteins. Loss of skeletal muscle mass is associated with an increased risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. The aim of this study was to clarify the effects of licorice flavonoid oil on muscle mass in KK-A y /Ta mice. Male genetically type II diabetic KK-A y /Ta mice received 0, 1, or 1.5 g/kg BW of licorice flavonoid oil by mouth once daily for 4 weeks. After 4 weeks, the femoral and soleus muscles were collected for western blotting for evaluation of the mTOR/p70 S6K, p38/FoxO3a, and Akt/FoxO3a signaling pathways. Ingestion of licorice flavonoid oil significantly enhanced femoral muscle mass without affecting body weight in KK-A y /Ta mice. Licorice flavonoid oil also decreased expression of MuRF1 and atrogin-1, which are both markers of muscle atrophy. The mechanisms by which licorice flavonoid oil enhances muscle mass include activation of mTOR and p70 S6K, and regulation of phosphorylation of FoxO3a. Ingestion of licorice flavonoids may help to prevent muscle atrophy. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Psoas muscle cross-sectional area as a measure of whole body lean muscle mass in maintenance hemodialysis patients

    PubMed Central

    Morrell, Glen R.; Ikizler, Talat A.; Chen, Xiaorui; Heilbrun, Marta E.; Wei, Guo; Boucher, Robert; Beddhu, Srinivasan

    2016-01-01

    Objective We investigate whether psoas or paraspinous muscle area measured on a single L4–5 image is a useful measure of whole lean body mass compared to dedicated mid-thigh magnetic resonance imaging (MRI). Design Observational study. Setting Outpatient dialysis units and a research clinic. Subjects 105 adult participants on maintenance hemodialysis. No control group was used. Exposure variables Psoas muscle area, paraspinous muscle area, and mid-thigh muscle area (MTMA) were measured by MRI. Main outcome measure Lean body mass was measured by dual-energy absorptiometry (DEXA) scan. Results In separate multivariable linear regression models, psoas, paraspinous, and mid-thigh muscle area were associated with increase in lean body mass. In separate multivariate logistic regression models, c-statistics for diagnosis of sarcopenia (defined as < 25th percentile of lean body mass) were 0.69 for paraspinous muscle area, 0.81 for psoas muscle area, and 0.89 for mid-thigh muscle area. With sarcopenia defined as < 10th percentile of lean body mass, the corresponding c-statistics were 0.71, 0.92, and 0.94. Conclusions We conclude that psoas muscle area provides a good measure of whole body muscle mass, better than paraspinous muscle area but slightly inferior to mid thigh measurement. Hence, in body composition studies a single axial MR image at the L4–L5 level can be used to provide information on both fat and muscle and may eliminate the need for time-consuming measurement of muscle area in the thigh. PMID:26994780

  11. Estimation of skeletal muscle mass from body creatine content

    NASA Technical Reports Server (NTRS)

    Pace, N.; Rahlmann, D. F.

    1982-01-01

    Procedures have been developed for studying the effect of changes in gravitational loading on skeletal muscle mass through measurements of the body creatine content. These procedures were developed for studies of gravitational scale effects in a four-species model, comprising the hamster, rat, guinea pig, and rabbit, which provides a sufficient range of body size for assessment of allometric parameters. Since intracellular muscle creatine concentration varies among species, and with age within a given species, the concentration values for metabolically mature individuals of these four species were established. The creatine content of the carcass, skin, viscera, smooth muscle, and skeletal muscle was determined for each species. In addition, the skeletal muscle mass of the major body components was determined, as well as the total and fat-free masses of the body and carcass, and the percent skeletal muscle in each. It is concluded that these procedures are particularly useful for studying the effect of gravitational loading on the skeletal muscle content of the animal carcass, which is the principal weight-bearing organ of the body.

  12. Soluble Milk Proteins Improve Muscle Mass Recovery after Immobilization-Induced Muscle Atrophy in Old Rats but Do not Improve Muscle Functional Property Restoration.

    PubMed

    Verney, J; Martin, V; Ratel, S; Chavanelle, V; Bargetto, M; Etienne, M; Chaplais, E; Le Ruyet, P; Bonhomme, C; Combaret, L; Guillet, C; Boisseau, N; Sirvent, P; Dardevet, D

    2017-01-01

    Effect of 3 different dairy protein sources on the recovery of muscle function after limb immobilization in old rats. Longitudinal animal study. Institut National de la Recherche Agronomique (INRA). The study took part in a laboratory setting. Old rats were subjected to unilateral hindlimb immobilization for 8 days and then allowed to recover with 3 different dietary proteins: casein, soluble milk proteins or whey proteins for 49 days. Body weight, muscle mass, muscle fibre size, isometric, isokinetic torque, muscle fatigability and muscle oxidative status were measured before and at the end of the immobilization period and during the recovery period i.e 7, 21, 35 and 49 days post immobilization. In contrast to the casein diet, soluble milk proteins and whey proteins were efficient to favor muscle mass recovery after cast immobilization during aging. By contrast, none of the 3 diary proteins was able to improve muscle strength, power and fatigability showing a discrepancy between the recovery of muscle mass and function. However, the soluble milk proteins allowed a better oxidative capacity in skeletal muscle during the rehabilitation period. Whey proteins and soluble milk proteins improve muscle mass recovery after immobilization-induced muscle atrophy in old rats but do not allow muscle functional property restoration.

  13. Absolute and Mass-Dependent Titanium Isotope Compositions of Solar System Materials

    NASA Astrophysics Data System (ADS)

    Williams, N. H.; Fehr, M. A.; Akram, W. M.; Parkinson, I. J.; Schönbächler, M.

    2013-09-01

    Mass dependent Ti isotope data for various solar system material will be presented. This data has been obtained via double spike technique using ^47 Ti and ^49Ti as spikes. Absolute nucleosynthetic anomalie data for Ti will be presented also.

  14. Comparison of muscle/lean mass measurement methods: correlation with functional and biochemical testing.

    PubMed

    Buehring, B; Siglinsky, E; Krueger, D; Evans, W; Hellerstein, M; Yamada, Y; Binkley, N

    2018-03-01

    DXA-measured lean mass is often used to assess muscle mass but has limitations. Thus, we compared DXA lean mass with two novel methods-bioelectric impedance spectroscopy and creatine (methyl-d3) dilution. The examined methodologies did not measure lean mass similarly and the correlation with muscle biomarkers/function varied. Muscle function tests predict adverse health outcomes better than lean mass measurement. This may reflect limitations of current mass measurement methods. Newer approaches, e.g., bioelectric impedance spectroscopy (BIS) and creatine (methyl-d3) dilution (D3-C), may more accurately assess muscle mass. We hypothesized that BIS and D3-C measured muscle mass would better correlate with function and bone/muscle biomarkers than DXA measured lean mass. Evaluations of muscle/lean mass, function, and serum biomarkers were obtained in older community-dwelling adults. Mass was assessed by DXA, BIS, and orally administered D3-C. Grip strength, timed up and go, and jump power were examined. Potential muscle/bone serum biomarkers were measured. Mass measurements were compared with functional and serum data using regression analyses; differences between techniques were determined by paired t tests. Mean (SD) age of the 112 (89F/23M) participants was 80.6 (6.0) years. The lean/muscle mass assessments were correlated (.57-.88) but differed (p < 0.0001) from one another with DXA total body less head being highest at 37.8 (7.3) kg, D3-C muscle mass at 21.1 (4.6) kg, and BIS total body intracellular water at 17.4 (3.5) kg. All mass assessment methods correlated with grip strength and jump power (R = 0.35-0.63, p < 0.0002), but not with gait speed or repeat chair rise. Lean mass measures were unrelated to the serum biomarkers measured. These three methodologies do not similarly measure muscle/lean mass and should not be viewed as being equivalent. Functional tests assessing maximal muscle strength/power (grip strength and jump power) correlated with

  15. TAK1 regulates skeletal muscle mass and mitochondrial function

    PubMed Central

    Hindi, Sajedah M.; Sato, Shuichi; Xiong, Guangyan; Bohnert, Kyle R.; Gibb, Andrew A.; Gallot, Yann S.; McMillan, Joseph D.; Hill, Bradford G.

    2018-01-01

    Skeletal muscle mass is regulated by a complex array of signaling pathways. TGF-β–activated kinase 1 (TAK1) is an important signaling protein, which regulates context-dependent activation of multiple intracellular pathways. However, the role of TAK1 in the regulation of skeletal muscle mass remains unknown. Here, we report that inducible inactivation of TAK1 causes severe muscle wasting, leading to kyphosis, in both young and adult mice.. Inactivation of TAK1 inhibits protein synthesis and induces proteolysis, potentially through upregulating the activity of the ubiquitin-proteasome system and autophagy. Phosphorylation and enzymatic activity of AMPK are increased, whereas levels of phosphorylated mTOR and p38 MAPK are diminished upon inducible inactivation of TAK1 in skeletal muscle. In addition, targeted inactivation of TAK1 leads to the accumulation of dysfunctional mitochondria and oxidative stress in skeletal muscle of adult mice. Inhibition of TAK1 does not attenuate denervation-induced muscle wasting in adult mice. Finally, TAK1 activity is highly upregulated during overload-induced skeletal muscle growth, and inactivation of TAK1 prevents myofiber hypertrophy in response to functional overload. Overall, our study demonstrates that TAK1 is a key regulator of skeletal muscle mass and oxidative metabolism. PMID:29415881

  16. Do muscle mass, muscle density, strength, and physical function similarly influence risk of hospitalization in older adults?

    PubMed

    Cawthon, Peggy Mannen; Fox, Kathleen M; Gandra, Shravanthi R; Delmonico, Matthew J; Chiou, Chiun-Fang; Anthony, Mary S; Sewall, Ase; Goodpaster, Bret; Satterfield, Suzanne; Cummings, Steven R; Harris, Tamara B

    2009-08-01

    To examine the association between strength, function, lean mass, muscle density, and risk of hospitalization. Prospective cohort study. Two U.S. clinical centers. Adults aged 70 to 80 (N=3,011) from the Health, Aging and Body Composition Study. Measurements were of grip strength, knee extension strength, lean mass, walking speed, and chair stand pace. Thigh computed tomography scans assessed muscle area and density (a proxy for muscle fat infiltration). Hospitalizations were confirmed by local review of medical records. Negative binomial regression models estimated incident rate ratios (IRRs) of hospitalization for race- and sex-specific quartiles of each muscle and function parameter separately. Multivariate models adjusted for age, body mass index, health status, and coexisting medical conditions. During an average 4.7 years of follow-up, 1,678 (55.7%) participants experienced one or more hospitalizations. Participants in the lowest quartile of muscle density were more likely to be subsequently hospitalized (multivariate IRR=1.47, 95% confidence interval (CI)=1.24-1.73) than those in the highest quartile. Similarly, participants with the weakest grip strength were at greater risk of hospitalization (multivariate IRR=1.52, 95% CI=1.30-1.78, Q1 vs. Q4). Comparable results were seen for knee strength, walking pace, and chair stands pace. Lean mass and muscle area were not associated with risk of hospitalization. Weak strength, poor function, and low muscle density, but not muscle size or lean mass, were associated with greater risk of hospitalization. Interventions to reduce the disease burden associated with sarcopenia should focus on increasing muscle strength and improving physical function rather than simply increasing lean mass.

  17. Type 2 diabetes is associated with low muscle mass in older adults.

    PubMed

    Kim, Kyung-Soo; Park, Kyung-Sun; Kim, Moon-Jong; Kim, Soo-Kyung; Cho, Yong-Wook; Park, Seok Won

    2014-02-01

    Our aim was to clarify the association between type 2 diabetes and the risk of low muscle mass in older adults. In the present study, 414 adults aged 65 years or older (144 patients with type 2 diabetes and 270 control participants) were included. Body composition was measured by dual-energy X-ray absorptiometry. Low muscle mass was defined as the appendicular skeletal muscle mass/height(2) (ASM/Ht(2)) or appendicular skeletal muscle mass/weight (ASM/Wt) of <2 SD below the sex-specific normal mean of the young reference group, or muscle mass/weight (TSM/Wt) from control participants. Older men with type 2 diabetes showed significantly lower appendicular skeletal muscle mass than those without diabetes (19.5 ± 3.5 kg vs 21.0 ± 2.8 kg, P < 0.001). The prevalence of low muscle mass was consistently higher in older men with diabetes than those without diabetes defined by ASM/Ht(2) (57.6% vs 41.5%, P = 0.040), ASM/Wt (23.7% vs 12.3%, P = 0.046) and TSM/Wt (49.2% vs 20.0%, P < 0.001). In older women with diabetes, the prevalence of low muscle mass was higher than those without diabetes by ASM/Wt (25.9% vs 15.0%, P = 0.044) and TSM/Wt (32.9% vs 20.0%, P = 0.030), but not by ASM/Ht(2) (7.1% vs 8.6%, P = 0.685). The risk of low muscle mass was approximately two- to fourfold higher in older adults with type 2 diabetes, even after adjusting for age, body mass index, current smoking and other risk factors. In Korean older adults, type 2 diabetes is associated with low muscle mass. © 2014 Japan Geriatrics Society.

  18. A low muscle mass increases mortality in compensated cirrhotic patients with sepsis.

    PubMed

    Lucidi, Cristina; Lattanzi, Barbara; Di Gregorio, Vincenza; Incicco, Simone; D'Ambrosio, Daria; Venditti, Mario; Riggio, Oliviero; Merli, Manuela

    2018-05-01

    Severe infections and muscle wasting are both associated to poor outcome in cirrhosis. A possible synergic effect of these two entities in cirrhotic patients has not been previously investigated. We aimed at analysing if a low muscle mass may deteriorate the outcome of cirrhotic patients with sepsis. Consecutive cirrhotic patients hospitalized for sepsis were enrolled in the study. Patients were classified for the severity of liver impairment (Child-Pugh class) and for the presence of "low muscle mass" (mid-arm muscle circumference<5th percentile). The development of complication during hospitalization and survival was analysed. There were 74 consecutive cirrhotics with sepsis. Forty-three of these patients showed low muscle mass. In patients with and without low muscle mass, severity of liver disease and characteristics of infections were similar. Mortality tended to be higher in patients with low muscle mass (47% vs 26%, P = .06). A multivariate analysis selected low muscle mass (P < .01, HR: 3.2, IC: 1.4-4.8) and Child-Pugh C (P < .01, HR: 3.3, 95% IC: 1.5-4.9) as independent predictors of in-hospital mortality. In Child-Pugh A-B patients, mortality was higher in patients with low muscle mass compared with those without (50% vs 16%; P = .01). The mortality rate and the incidence of complications in malnourished patients classified in Child-Pugh A-B were similar to those Child-Pugh C. Low muscle mass worsen prognosis in cirrhotic patients with severe infections. This is particularly evident in patients with Child A-B cirrhosis in whom the coexistence of low muscle mass and sepsis caused a negative impact on mortality similar to that observable in all Child C patients with sepsis. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Relative and Absolute Interrater Reliabilities of a Hand-Held Myotonometer to Quantify Mechanical Muscle Properties in Patients with Acute Stroke in an Inpatient Ward

    PubMed Central

    2017-01-01

    Introduction The reliability of using MyotonPRO to quantify muscles mechanical properties in a ward setting for the acute stroke population remains unknown. Aims To investigate the within-session relative and absolute interrater reliability of MyotonPRO. Methods Mechanical properties of biceps brachii, brachioradialis, rectus femoris, and tibialis anterior were recorded at bedside. Participants were within 1 month of the first occurrence of stroke. Relative reliability was assessed by intraclass correlation coefficient (ICC). Absolute reliability was assessed by standard error of measurement (SEM), SEM%, smallest real difference (SRD), SRD%, and the Bland-Altman 95% limits of agreement. Results ICCs of all studied muscles ranged between 0.63 and 0.97. The SEM of all muscles ranged within 0.30–0.88 Hz for tone, 0.07–0.19 for decrement, 6.42–20.20 N/m for stiffness, and 0.04–0.07 for creep. The SRD of all muscles ranged within 0.70–2.05 Hz for tone, 0.16–0.45 for decrement, 14.98–47.15 N/m for stiffness, and 0.09–0.17 for creep. Conclusions MyotonPRO demonstrated acceptable relative and absolute reliability in a ward setting for patients with acute stroke. However, results must be interpreted with caution, due to the varying level of consistency between different muscles, as well as between different parameters within a muscle. PMID:29164148

  20. The impact of obesity on skeletal muscle strength and structure through adolescence to old age.

    PubMed

    Tomlinson, D J; Erskine, R M; Morse, C I; Winwood, K; Onambélé-Pearson, Gladys

    2016-06-01

    Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.

  1. Can absolute and proportional anthropometric characteristics distinguish stronger and weaker powerlifters?

    PubMed

    Keogh, Justin W L; Hume, Patria A; Pearson, Simon N; Mellow, Peter J

    2009-11-01

    This study sought to compare the anthropometric profiles of 17 weaker and 17 stronger Australasian and Pacific powerlifters who had competed in a regional-, national-, or international-level powerlifting competition in New Zealand. Stronger lifters were defined as those having a Wilks score greater than 410, whereas those in the weaker group had a Wilks score less than 370. Each powerlifter was assessed for 37 anthropometric dimensions by International Society for the Advancement of Kinanthropometry (ISAK) level II and III accredited anthropometrists. Because all powerlifters were highly mesomorphic and possessed large girths and bone breadths, both in absolute terms and when expressed as Phantom-Z scores compared through the Phantom, relatively few significant anthropometric differences were observed. However, stronger lifters had significantly greater muscle mass and larger muscular girths in absolute terms as well as greater Brugsch Index (chest girth/height) and "Phantom"-normalized muscle mass, upper arm, chest, and forearm girths. In terms of the segment lengths and bone breadths, the only significant difference was that stronger lifters had a significantly shorter lower leg than weaker lifters. Because the majority of the significant differences were for muscle mass and muscular girths, it would appear likely that these differences contributed to the stronger lifters' superior performance. Powerlifters may therefore need to devote some of their training to the development of greater levels of muscular hypertrophy if they wish to continue to improve their performance. To better understand the anthropometric determinants of muscular strength, future research should recruit larger samples (particularly of elite lifters) and follow these subjects prospectively.

  2. An investigation of abdominal muscle recruitment for sustained phonation in 25 healthy singers.

    PubMed

    Macdonald, Ian; Rubin, John S; Blake, Ed; Hirani, Shashi; Epstein, Ruth

    2012-11-01

    The purpose of this study was to investigate the baseline muscle thickness and recruitment patterns of the transversus abdominis muscle (TAM) and the internal oblique muscle (IOM) during semisupine phonation in a group of healthy performers. This was a 2 × 3×2 within-group, repeated-measure study in which 25 professional vocalists--12 male and 13 female performed a series of sustained pitches in differing vocal qualities. Measurements were taken with ultrasound (Sonosite Micromaxx Ultrasound System) of the baseline thickness and % recruitment during voicing, of two deep abdominal muscles--TAM and the IOM. Correlations between TAM and IOM absolute change scores, TAM and IOM percentage change scores, and changes in muscle thickness (absolute and percentage) and age were examined using Spearman's correlations. Gender differences in the four types of change scores within each combination of pitch and quality were conducted with one-way analysis of variances. Differences in muscle thickness change 1) absolute scores and 2) percentage change in TAM and IOM, by pitch and quality (and their interactions) were analyzed using linear mixed models, using restricted maximum likelihood estimations, employing a Toeplitz variance-covariance matrix structure in SPSS (IBM, 2011). Post hoc analyses for independent variable group differences used Sidak's correction for multiple comparisons. Alpha level was set to 0.05. In terms of absolute contractions (changes in the actual millimeter thickness of the muscle), the IOM was greater than the TAM. However in terms of percentage changes in muscles during phonation, the TAM was always greater than the IOM. The TAM as a percentage change was recruited preferentially and significantly in most vocal qualities tested. Although there were differences in muscle mass and recruitment patterns between genders, and males had thicker muscle mass at rest, differences due to muscle mass were not conclusive. Overall this study supports the argument

  3. Beef extract supplementation increases leg muscle mass and modifies skeletal muscle fiber types in rats.

    PubMed

    Yoshihara, Hiroyuki; Wakamatsu, Jun-Ichiro; Kawabata, Fuminori; Mori, Sunao; Haruno, Atsushi; Hayashi, Toshiya; Sekiguchi, Takeshi; Mizunoya, Wataru; Tatsumi, Ryuichi; Ito, Tatsumi; Ikeuchi, Yoshihide

    2006-06-01

    The objective of this research was to investigate the effects of beef extract on fat metabolism, muscle mass and muscle fiber types in rats. We also investigated the synergetic effect of endurance exercise. Twenty-four male rats weighing about 270 g were assigned to two diets containing 0 or 6% beef extract (BE). Half the rats fed each diet were subjected to compulsory exercise (CE) for 30 min every other day. After 4 weeks feeding, the blood was collected and various organs were dissected. The muscle fiber type of the soleus and extensor digitorum longus (EDL) muscles were evaluated by histochemical and electrophoretical analyses. Rats supplemented with BE showed a decrease in fat content in liver and abdomen and an increase in the activity of carnitine palmitoyl transferase II in liver. BE as well as exercise increased the relative weights of both soleus and EDL. BE alone and BE plus CE did not affect the distribution of muscle fiber types in soleus. BE without exercise decreased in type IIb of EDL from 54% to 44% with compensatory increase in type IIa from 41% to 49% and type I from 5% to 7% compared with the nonsupplemented, nonexercised control group. No synergetic effect on a fast to slow fiber conversion due to the combination of BE and CE was detected. Thus, BE supplement increased muscle mass and slow type fiber in EDL. The effects of BE supplement on muscle characteristics were similar to those of exercise. beef extract, fat metabolism, muscle fiber type, muscle mass, L-carnitine

  4. Muscle Mass Depletion Associated with Poor Outcome of Sepsis in the Emergency Department.

    PubMed

    Lee, YoonJe; Park, Hyun Kyung; Kim, Won Young; Kim, Myung Chun; Jung, Woong; Ko, Byuk Sung

    2018-05-08

    Muscle mass depletion has been suggested to predict morbidity and mortality in various diseases. However, it is not well known whether muscle mass depletion is associated with poor outcome in sepsis. We hypothesized that muscle mass depletion is associated with poor outcome in sepsis. Retrospective observational study was conducted in an emergency department during a 9-year period. Medical records of 627 patients with sepsis were reviewed. We divided the patients into 2 groups according to 28-day mortality and compared the presence of muscle mass depletion assessed by the cross-sectional area of the psoas muscle at the level of the third lumbar vertebra on abdomen CT scans. Univariate and multivariate logistic regression analyses were conducted to examine the association of scarcopenia on the outcome of sepsis. A total of 274 patients with sepsis were finally included in the study: 45 (16.4%) did not survive on 28 days and 77 patients (28.1%) were identified as having muscle mass depletion. The presence of muscle mass depletion was independently associated with 28-day mortality on multivariate logistic analysis (OR 2.79; 95% CI 1.35-5.74, p = 0.01). Muscle mass depletion evaluated by CT scan was associated with poor outcome of sepsis patients. Further studies on the appropriateness of specific treatment for muscle mass depletion with sepsis are needed. © 2018 S. Karger AG, Basel.

  5. Subclinical hypothyroidism has little influences on muscle mass or strength in elderly people.

    PubMed

    Moon, Min Kyong; Lee, You Jin; Choi, Sung Hee; Lim, Soo; Yang, Eun Joo; Lim, Jae-Young; Paik, Nam-Jong; Kim, Ki Woong; Park, Kyong Soo; Jang, Hak C; Cho, Bo Youn; Park, Young Joo

    2010-08-01

    Sarcopenia, the age-related decline in muscle mass, affects the muscle strength and muscle quality, and these changes decrease functional capacity. The prevalence of thyroid dysfunction increases with age, and changes in thyroid hormone level lead to neuromuscular deficits. We investigated the effects of subclinical hypothyroidism on the muscle mass, strength or quality in elderly people. One thousand one hundred eighteen subjects aged > or = 65 yr were randomly selected from a local population and classified into a euthyroid (280 men and 358 women), subclinically hypothyroid (61 men and 75 women), or overtly hypothyroid (7 men and 16 women) group. Although women with subclinical hypothyroidism had a higher prevalence of sarcopenia, defined according to the ratio of appendicular skeletal muscle mass to the square of height, muscle mass, strength or quality did not differ in relation to thyroid status in men or in women. Multivariate analysis including age, diabetes, hypertension, acute coronary event, alcohol, smoking, presence of pain, physical activity score, and lipid profile, showed that thyroid-stimulating hormone level was not associated with muscle mass, strength or quality. In conclusion, subclinical hypothyroidism has little influences on muscle mass, strength or quality, and may not be associated with sarcopenia.

  6. The AMPK-related kinase SNARK regulates muscle mass and myocyte survival

    PubMed Central

    Lessard, Sarah J.; Rivas, Donato A.; So, Kawai; Koh, Ho-Jin; Queiroz, André Lima; Hirshman, Michael F.; Fielding, Roger A.; Goodyear, Laurie J.

    2015-01-01

    The maintenance of skeletal muscle mass is critical for sustaining health; however, the mechanisms responsible for muscle loss with aging and chronic diseases, such as diabetes and obesity, are poorly understood. We found that expression of a member of the AMPK-related kinase family, the SNF1-AMPK-related kinase (SNARK, also known as NUAK2), increased with muscle cell differentiation. SNARK expression increased in skeletal muscles from young mice exposed to metabolic stress and in muscles from healthy older human subjects. The regulation of SNARK expression in muscle with differentiation and physiological stress suggests that SNARK may function in the maintenance of muscle mass. Consistent with this hypothesis, decreased endogenous SNARK expression (using siRNA) in cultured muscle cells resulted in increased apoptosis and decreased cell survival under conditions of metabolic stress. Likewise, muscle-specific transgenic animals expressing a SNARK dominant-negative inactive mutant (SDN) had increased myonuclear apoptosis and activation of apoptotic mediators in muscle. Moreover, animals expressing SDN had severe, age-accelerated muscle atrophy and increased adiposity, consistent with sarcopenic obesity. Reduced SNARK activity, in vivo and in vitro, caused downregulation of the Rho kinase signaling pathway, a key mediator of cell survival. These findings reveal a critical role for SNARK in myocyte survival and the maintenance of muscle mass with age. PMID:26690705

  7. Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia

    PubMed Central

    Ismail, Catheeja; Zabal, Johannah; Hernandez, Haniel J.; Woletz, Paula; Manning, Heather; Teixeira, Carla; DiPietro, Loretta; Blackman, Marc R.; Harris-Love, Michael O.

    2015-01-01

    Introduction: Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance. Methods: Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht2), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m2 determined participant assignment into the Normal LBM and Low LBM subgroups. Results: The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht2 (adj. R2 = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R2 = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R2 = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05). Conclusions: Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht2 in women. In addition, ultrasound proxy measures of muscle quality are more

  8. Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia.

    PubMed

    Ismail, Catheeja; Zabal, Johannah; Hernandez, Haniel J; Woletz, Paula; Manning, Heather; Teixeira, Carla; DiPietro, Loretta; Blackman, Marc R; Harris-Love, Michael O

    2015-01-01

    Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance. Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht(2)), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m(2) determined participant assignment into the Normal LBM and Low LBM subgroups. The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht(2) (adj. R (2) = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R (2) = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R (2) = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05). Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht(2) in women. In addition, ultrasound proxy measures of muscle quality are more strongly associated with

  9. Maintenance of muscle mass and load-induced growth in Muscle RING Finger 1 null mice with age.

    PubMed

    Hwee, Darren T; Baehr, Leslie M; Philp, Andrew; Baar, Keith; Bodine, Sue C

    2014-02-01

    Age-related loss of muscle mass occurs to varying degrees in all individuals and has a detrimental effect on morbidity and mortality. Muscle RING Finger 1 (MuRF1), a muscle-specific E3 ubiquitin ligase, is believed to mediate muscle atrophy through the ubiquitin proteasome system (UPS). Deletion of MuRF1 (KO) in mice attenuates the loss of muscle mass following denervation, disuse, and glucocorticoid treatment; however, its role in age-related muscle loss is unknown. In this study, skeletal muscle from male wild-type (WT) and MuRF1 KO mice was studied up to the age of 24 months. Muscle mass and fiber cross-sectional area decreased significantly with age in WT, but not in KO mice. In aged WT muscle, significant decreases in proteasome activities, especially 20S and 26S β5 (20-40% decrease), were measured and were associated with significant increases in the maladaptive endoplasmic reticulum (ER) stress marker, CHOP. Conversely, in aged MuRF1 KO mice, 20S or 26S β5 proteasome activity was maintained or decreased to a lesser extent than in WT mice, and no increase in CHOP expression was measured. Examination of the growth response of older (18 months) mice to functional overload revealed that old WT mice had significantly less growth relative to young mice (1.37- vs. 1.83-fold), whereas old MuRF1 KO mice had a normal growth response (1.74- vs. 1.90-fold). These data collectively suggest that with age, MuRF1 plays an important role in the control of skeletal muscle mass and growth capacity through the regulation of cellular stress. © 2013 the Anatomical Society and John Wiley & Sons Ltd.

  10. Relationship between oxidative stress and muscle mass loss in early postmenopause: an exploratory study.

    PubMed

    Zacarías-Flores, Mariano; Sánchez-Rodríguez, Martha A; García-Anaya, Oswaldo Daniel; Correa-Muñoz, Elsa; Mendoza-Núñez, Víctor Manuel

    2018-04-09

    Endocrine changes due to menopause have been associated to oxidative stress and muscle mass loss. The study objective was to determine the relationship between both variables in early postmenopause. An exploratory, cross-sectional study was conducted in 107 pre- and postmenopausal women (aged 40-57 years). Levels of serum lipid peroxides and uric acid and enzymes superoxide dismutase and glutathione peroxidase, as well as total plasma antioxidant capacity were measured as oxidative stress markers. Muscle mass using bioelectrical impedance and muscle strength using dynamometry were also measured. Muscle mass, skeletal muscle index, fat-free mass, and body mass index were calculated. More than 90% of participants were diagnosed with overweight or obesity. Postmenopausal women had lower values of muscle mass and strength markers, with a negative correlation between lipid peroxide level and skeletal muscle index (r= -0.326, p<.05), and a positive correlation between uric acid and skeletal muscle index (r=0.295, p<.05). A multivariate model including oxidative stress markers, age, and waist circumference showed lipid peroxide level to be the main contributor to explain the decrease in skeletal muscle mass in postmenopause, since for every 0.1μmol/l increase in lipid peroxide level, skeletal muscle index decreases by 3.03 units. Our findings suggest an association between increased oxidative stress and muscle mass loss in early postmenopause. Copyright © 2018 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Subclinical Hypothyroidism has Little Influences on Muscle Mass or Strength in Elderly People

    PubMed Central

    Moon, Min Kyong; Lee, You Jin; Choi, Sung Hee; Lim, Soo; Yang, Eun Joo; Lim, Jae-Young; Paik, Nam-Jong; Kim, Ki Woong; Park, Kyong Soo; Jang, Hak C.

    2010-01-01

    Sarcopenia, the age-related decline in muscle mass, affects the muscle strength and muscle quality, and these changes decrease functional capacity. The prevalence of thyroid dysfunction increases with age, and changes in thyroid hormone level lead to neuromuscular deficits. We investigated the effects of subclinical hypothyroidism on the muscle mass, strength or quality in elderly people. One thousand one hundred eighteen subjects aged ≥65 yr were randomly selected from a local population and classified into a euthyroid (280 men and 358 women), subclinically hypothyroid (61 men and 75 women), or overtly hypothyroid (7 men and 16 women) group. Although women with subclinical hypothyroidism had a higher prevalence of sarcopenia, defined according to the ratio of appendicular skeletal muscle mass to the square of height, muscle mass, strength or quality did not differ in relation to thyroid status in men or in women. Multivariate analysis including age, diabetes, hypertension, acute coronary event, alcohol, smoking, presence of pain, physical activity score, and lipid profile, showed that thyroid-stimulating hormone level was not associated with muscle mass, strength or quality. In conclusion, subclinical hypothyroidism has little influences on muscle mass, strength or quality, and may not be associated with sarcopenia. PMID:20676329

  12. Relationship of Muscle Mass Determined by DEXA with Spirometric Results in Healthy Individuals.

    PubMed

    Martín Holguera, Rafael; Turrión Nieves, Ana Isabel; Rodríguez Torres, Rosa; Alonso, María Concepción

    2017-07-01

    Muscle mass maybe a determining factor in the variability of spirometry results in individuals of the same sex and age who have similar anthropometric characteristics. The aim of this study was to determine the association between spirometric results from healthy individuals and their muscle mass assessed by dual energy X-ray absorptiometry (DEXA). A sample of 161 women and 144 men, all healthy non-smokers, was studied. Ages ranged from18 to77years. For each subject, spirometry results and total and regional lean mass values obtained by full body DEXA were recorded. A descriptive analysis of the variables and a regression analysis were performed to study the relationship between spirometric variables and lean body mass, correcting for age and body mass index (BMI). In both sexes all muscle mass variables correlated positively and significantly with spirometric variables, and to a greater extent in men. After partial adjustment of correlations by age and BMI, the factor which best explains the spirometric variables is the total lean body mass in men, and trunk lean body mass in women. In men, muscle mass in the lower extremities is most closely associated with spirometric results. In women, it is the muscle mass of the trunk. In both sexes muscle mass mainly affects FEV 1 . Copyright © 2016 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Increasing Muscle Mass Improves Vascular Function in Obese (db/db) Mice

    PubMed Central

    Qiu, Shuiqing; Mintz, James D.; Salet, Christina D.; Han, Weihong; Giannis, Athanassios; Chen, Feng; Yu, Yanfang; Su, Yunchao; Fulton, David J.; Stepp, David W.

    2014-01-01

    Background A sedentary lifestyle is an independent risk factor for cardiovascular disease and exercise has been shown to ameliorate this risk. Inactivity is associated with a loss of muscle mass, which is also reversed with isometric exercise training. The relationship between muscle mass and vascular function is poorly defined. The aims of the current study were to determine whether increasing muscle mass by genetic deletion of myostatin, a negative regulator of muscle growth, can influence vascular function in mesenteric arteries from obese db/db mice. Methods and Results Myostatin expression was elevated in skeletal muscle of obese mice and associated with reduced muscle mass (30% to 50%). Myostatin deletion increased muscle mass in lean (40% to 60%) and obese (80% to 115%) mice through increased muscle fiber size (P<0.05). Myostatin deletion decreased adipose tissue in lean mice, but not obese mice. Markers of insulin resistance and glucose tolerance were improved in obese myostatin knockout mice. Obese mice demonstrated an impaired endothelial vasodilation, compared to lean mice. This impairment was improved by superoxide dismutase mimic Tempol. Deletion of myostatin improved endothelial vasodilation in mesenteric arteries in obese, but not in lean, mice. This improvement was blunted by nitric oxide (NO) synthase inhibitor l‐NG‐nitroarginine methyl ester (l‐NAME). Prostacyclin (PGI2)‐ and endothelium‐derived hyperpolarizing factor (EDHF)‐mediated vasodilation were preserved in obese mice and unaffected by myostatin deletion. Reactive oxygen species) was elevated in the mesenteric endothelium of obese mice and down‐regulated by deletion of myostatin in obese mice. Impaired vasodilation in obese mice was improved by NADPH oxidase inhibitor (GKT136901). Treatment with sepiapterin, which increases levels of tetrahydrobiopterin, improved vasodilation in obese mice, an improvement blocked by l‐NAME. Conclusions Increasing muscle mass by genetic

  14. Association between healthy diet and exercise and greater muscle mass in older adults.

    PubMed

    Kim, Jinhee; Lee, Yunhwan; Kye, Seunghee; Chung, Yoon-Sok; Kim, Kwang-Min

    2015-05-01

    To examine the association between healthy diet and exercise, individually and combined, and low muscle mass in older Korean adults. Population-based cross-sectional study from the Fourth and Fifth Korea National Health and Nutrition Examination Surveys from 2008 to 2011. Community. Nationally representative sample aged 65 and older (1,486 men, 1,799 women) in the Republic of Korea. A food frequency questionnaire was used to determine frequency of food group consumption (meat, fish, eggs, legumes; vegetables; fruits). Participation in exercise (aerobic and resistance) was based on self-report. Combined healthy lifestyle factors were calculated as the number of recommendations met regarding consumption of food groups and exercise performed. Appendicular skeletal muscle mass (ASM) was measured using dual-energy X-ray absorptiometry, and low muscle mass was defined using the variable of ASM adjusted for weight. Logistic regression analysis was performed to examine the association between healthy lifestyle factors and low muscle mass, adjusting for sociodemographic characteristics and health-related variables. In women, after controlling for covariates, vegetable consumption (odds ratio (OR)=0.52, 95% confidence interval (CI)=0.30-0.89) and aerobic exercise (OR=0.62, 95% CI=0.39-1.00) were inversely associated with low muscle mass. Also, the odds of low muscle mass was lower in women with three or more healthy lifestyle factors versus none (OR=0.45, 95% CI=0.23-0.87). In men, there were no associations between food group consumption and exercise and low muscle mass. Older women who exercise and consume a healthy diet have lower odds of low muscle mass. Engaging in multiple healthy behaviors may be important in preventing low muscle mass in late life. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

  15. Isoflavin-β modifies muscle oxidative stress and prevents a thyrotoxicosis-induced loss of muscle mass in rats.

    PubMed

    Marinello, Poliana C; Bernardes, Sara S; Guarnier, Flávia A; Da Silva, Thamara N X; Borges, Fernando H; Lopes, Natália M D; Simão, Andréa N C; Armani, André; Cecchini, Rubens; Cecchini, Alessandra L

    2017-11-01

    We sought to verify whether isoflavin-beta (Iso-β), a mixture of isoflavones with antioxidant properties, could prevent thyrotoxicosis-induced loss of muscle mass and the participation of oxidative stress (OS) in the mechanisms of this prevention. Two experimental periods of thyrotoxicosis induction were used in Wistar rats: 3 and 5 days to assess Iso-β effects before and after thyrotoxicosis-induced muscle wasting. After euthanasia, peritoneal fat and gastrocnemius muscle were collected, weighed, and muscle OS was assessed. Iso-β prevented the loss of gastrocnemius mass in thyrotoxic rats through the prevention of muscle OS generation during thyrotoxicosis, increasing muscle total antioxidant capacity and decreasing mitochondrial cytochrome c oxidase activity, lipid peroxidation, and protein carbonyl content. Iso-β decreased oxidative modification of proteins, which is known to exert a major role during proteolysis induction and is present in thyrotoxic myopathy, highlighting the potential action of Iso-β in this complication of the disease. Muscle Nerve 56: 975-981, 2017. © 2016 Wiley Periodicals, Inc.

  16. [METHODS OF EVALUATION OF MUSCLE MASS: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS].

    PubMed

    Moreira, Osvaldo Costa; de Oliveira, Cláudia Eliza Patrocínio; Candia-Luján, Ramón; Romero-Pérez, Ena Monserrat; de Paz Fernandez, José Antonio

    2015-09-01

    in recent years, research about muscle mass has gained popularity for their relationship to health. Thus precise measurement of muscle mass may have clinical application once may interfere with the diagnosis and prescription drug or drug treatment. to conduct a systematic review of the methods most used for evaluation of muscle mass in randomized controlled trials, with its advantages and disadvantages. we conducted a search of the data bases Pub- Med, Web of Science and Scopus, with words "muscle mass", "measurement", "assessment" and "evaluation", combined in this way: "muscle mass" AND (assessment OR measurement OR evaluation). 23 studies were recovered and analyzed, all in English. 69.56% only used a method for quantification of muscle mass; 69.57% used dual X-ray absorptiometry (DXA); in 45.46% the type of measure used was the body lean mass; and 51.61% chose the whole body as a site of measurement. in the randomized controlled trials analyzed the majority used just one method of assessment, with the DXA being the method most used, the body lean mass the measurement type most used and total body the most common site of measure. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  17. Relationships of 35 lower limb muscles to height and body mass quantified using MRI.

    PubMed

    Handsfield, Geoffrey G; Meyer, Craig H; Hart, Joseph M; Abel, Mark F; Blemker, Silvia S

    2014-02-07

    Skeletal muscle is the most abundant tissue in the body and serves various physiological functions including the generation of movement and support. Whole body motor function requires adequate quantity, geometry, and distribution of muscle. This raises the question: how do muscles scale with subject size in order to achieve similar function across humans? While much of the current knowledge of human muscle architecture is based on cadaver dissection, modern medical imaging avoids limitations of old age, poor health, and limited subject pool, allowing for muscle architecture data to be obtained in vivo from healthy subjects ranging in size. The purpose of this study was to use novel fast-acquisition MRI to quantify volumes and lengths of 35 major lower limb muscles in 24 young, healthy subjects and to determine if muscle size correlates with bone geometry and subject parameters of mass and height. It was found that total lower limb muscle volume scales with mass (R(2)=0.85) and with the height-mass product (R(2)=0.92). Furthermore, individual muscle volumes scale with total muscle volume (median R(2)=0.66), with the height-mass product (median R(2)=0.61), and with mass (median R(2)=0.52). Muscle volume scales with bone volume (R(2)=0.75), and muscle length relative to bone length is conserved (median s.d.=2.1% of limb length). These relationships allow for an arbitrary subject's individual muscle volumes to be estimated from mass or mass and height while muscle lengths may be estimated from limb length. The dataset presented here can further be used as a normative standard to compare populations with musculoskeletal pathologies. © 2013 Published by Elsevier Ltd.

  18. Differences among skeletal muscle mass indices derived from height-, weight-, and body mass index-adjusted models in assessing sarcopenia

    PubMed Central

    Kim, Kyoung Min; Jang, Hak Chul; Lim, Soo

    2016-01-01

    Aging processes are inevitably accompanied by structural and functional changes in vital organs. Skeletal muscle, which accounts for 40% of total body weight, deteriorates quantitatively and qualitatively with aging. Skeletal muscle is known to play diverse crucial physical and metabolic roles in humans. Sarcopenia is a condition characterized by significant loss of muscle mass and strength. It is related to subsequent frailty and instability in the elderly population. Because muscle tissue is involved in multiple functions, sarcopenia is closely related to various adverse health outcomes. Along with increasing recognition of the clinical importance of sarcopenia, several international study groups have recently released their consensus on the definition and diagnosis of sarcopenia. In practical terms, various skeletal muscle mass indices have been suggested for assessing sarcopenia: appendicular skeletal muscle mass adjusted for height squared, weight, or body mass index. A different prevalence and different clinical implications of sarcopenia are highlighted by each definition. The discordances among these indices have emerged as an issue in defining sarcopenia, and a unifying definition for sarcopenia has not yet been attained. This review aims to compare these three operational definitions and to introduce an optimal skeletal muscle mass index that reflects the clinical implications of sarcopenia from a metabolic perspective. PMID:27334763

  19. The influence of different muscle mass measurements on the diagnosis of cancer cachexia

    PubMed Central

    Blauwhoff‐Buskermolen, Susanne; Langius, Jacqueline A.E.; Becker, Annemarie; Verheul, Henk M.W.

    2017-01-01

    Abstract Background Progressive loss of muscle mass is a major characteristic of cancer cachexia. Consensus definitions for cachexia provide different options to measure muscle mass. This study describes the effect of different methods to determine muscle mass on the diagnosis of cancer cachexia. In addition, the association of cachexia with other features of cachexia, quality of life, and survival was explored. Methods Prior to chemotherapy, cachexia was assessed by weight loss, body mass index, and muscle mass measurements, the latter by mid‐upper arm muscle area (MUAMA), computed tomography (CT) scans, and bio‐electrical impedance analysis (BIA). In addition, appetite, inflammation, muscle strength, fatigue, quality of life, and survival were measured, and associations with cachexia were explored. Results Included were 241 patients with advanced cancer of the lung (36%), colon/rectum (31%), prostate (18%), or breast (15%). Mean age was 64 ± 10 years; 54% was male. Prevalence of low muscle mass was as follows: 13% with MUAMA, 59% with CT, and 93% with BIA. In turn, the prevalence of cachexia was 37, 43, and 48%, whereby weight loss >5% was the most prominent component of being defined cachectic. Irrespective of type of muscle measurement, patients with cachexia presented more often with anorexia, inflammation, low muscle strength, and fatigue and had lower quality of life. Patients with cachexia had worse overall survival compared with patients without cachexia: HRs 2.00 (1.42–2.83) with MUAMA, 1.64 (1.15–2.34) with CT, and 1.50 (1.05–2.14) with BIA. Conclusions Although the prevalence of low muscle mass in patients with cancer depended largely on the type of muscle measurement, this had little influence on the diagnosis of cancer cachexia (as the majority of patients was already defined cachectic based on weight loss). New studies are warranted to further elucidate the additional role of muscle measurements in the diagnosis of cachexia and the

  20. Muscle mass and composition of the hip, thigh and abdominal muscles in women with and without hip osteoarthritis.

    PubMed

    Fukumoto, Yoshihiro; Ikezoe, Tome; Tateuchi, Hiroshige; Tsukagoshi, Rui; Akiyama, Haruhiko; So, Kazutaka; Kuroda, Yutaka; Yoneyama, Tomohide; Ichihashi, Noriaki

    2012-09-01

    The objective of this study was to compare muscle mass and composition between individuals with and without hip osteoarthritis. Twenty-four women with hip osteoarthritis (OA group) and 16 healthy women (healthy group) participated in this study. Muscle thickness (MT) and echo intensity (EI) were measured as indices of muscle mass and composition, respectively, using ultrasound imaging. Seven muscles were examined: gluteus maximus, gluteus medius, quadriceps femoris, rectus abdominis, external oblique, internal oblique and transversus abdominis. MT of only quadriceps femoris in the OA group was significantly thinner than that in the healthy group. EIs of gluteus medius, quadriceps femoris and rectus abdominis were significantly higher in the OA group than those in the healthy group. Thus, actual contractile tissue of gluteus medius and rectus abdominis substantially decreased, although muscle mass was similar, whereas both quantitative and qualitative changes occurred in quadriceps femoris in patients with hip OA. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  1. Fat-Free Mass and Skeletal Muscle Mass Five Years After Bariatric Surgery.

    PubMed

    Davidson, Lance E; Yu, Wen; Goodpaster, Bret H; DeLany, James P; Widen, Elizabeth; Lemos, Thaisa; Strain, Gladys W; Pomp, Alfons; Courcoulas, Anita P; Lin, Susan; Janumala, Isaiah; Thornton, John C; Gallagher, Dympna

    2018-07-01

    This study investigated changes in fat-free mass (FFM) and skeletal muscle 5 years after surgery in participants from the Longitudinal Assessment of Bariatric Surgery-2 trial. A three-compartment model assessed FFM, and whole-body magnetic resonance imaging (MRI) quantified skeletal muscle mass prior to surgery (T0) and 1 year (T1), 2 years (T2), and 5 years (T5) postoperatively in 93 patients (85% female; 68% Caucasian; age 44.2 ± 11.6 years) who underwent gastric bypass (RYGB), sleeve gastrectomy, or adjustable gastric band. Repeated-measures mixed models were used to analyze the data. Significant weight loss occurred across all surgical groups in females from T0 to T1. FFM loss from T0 to T1 was greater after RYGB (mean ± SE: -6.9 ± 0.6 kg) than adjustable gastric band (-3.5 ± 1.4 kg; P < 0.05). Females with RYGB continued to lose FFM (-3.3 ± 0.7 kg; P < 0.001) from T1 to T5. A subset of males and females with RYGB and MRI-measured skeletal muscle showed similar initial FFM loss while maintaining FFM and skeletal muscle from T1 to T5. Between 1 and 5 years following common bariatric procedures, FFM and skeletal muscle are maintained or decrease minimally. The changes observed in FFM and muscle during the follow-up phase may be consistent with aging. © 2018 The Obesity Society.

  2. Appendicular Skeletal Muscle Mass Reference Values and the Peak Muscle Mass to Identify Sarcopenia among Iranian Healthy Population.

    PubMed

    Shafiee, Gita; Ostovar, Afshin; Heshmat, Ramin; Keshtkar, Abbas Ali; Sharifi, Farshad; Shadman, Zhaleh; Nabipour, Iraj; Soltani, Akbar; Larijani, Bagher

    2018-01-01

    Sacopenia is a common problem in elderly with the adverse outcomes. The objective of this study was to estimate the peak appendicular skeletal muscle mass (ASM) and age of its attainment by sex among the Iranian population. A total of 691 men and women aged 18-94 years participated in this cross-sectional, population-based study in Bushehr, Iran. ASM was measured by dual X-ray absorptiometry. Cutoff points for men and women were established considering two standard deviations (SDs) below the mean values of the skeletal muscle index (SMI) for young reference groups. The relationship between ASM and age was described by the second-degree regression models. Two SDs below the mean SMIs of reference groups were as cutoff values of low muscle mass in Iranian population. The peak ASM values were 21.35 ± 0.12 Kg and 13.68 ± 0.10 Kg, and the age at peak ASM were 26 (24-28) years and 34 (33-35) years for men and women, respectively. Mean and SD of SMI in those ages were 7.01 ± 0.02 Kg/m 2 and 5.44 ± 0.02 Kg/m 2 among men and women, respectively. Calculated cutoff values of low muscle mass among the Iranian population were 7.0 Kg/m 2 and 5.4 Kg/m 2 among men and women, respectively. Iranian reference values of SMI for both genders were similar to Asia Working Group for Sarcopenia recommendation and lower than the United States and European values. Further studies from different nations and the Middle East countries are needed to obtain reference values for populations, enabling the researchers for comparison and also more valid reports on sarcopenia prevalence.

  3. The influence of different muscle mass measurements on the diagnosis of cancer cachexia.

    PubMed

    Blauwhoff-Buskermolen, Susanne; Langius, Jacqueline A E; Becker, Annemarie; Verheul, Henk M W; de van der Schueren, Marian A E

    2017-08-01

    Progressive loss of muscle mass is a major characteristic of cancer cachexia. Consensus definitions for cachexia provide different options to measure muscle mass. This study describes the effect of different methods to determine muscle mass on the diagnosis of cancer cachexia. In addition, the association of cachexia with other features of cachexia, quality of life, and survival was explored. Prior to chemotherapy, cachexia was assessed by weight loss, body mass index, and muscle mass measurements, the latter by mid-upper arm muscle area (MUAMA), computed tomography (CT) scans, and bio-electrical impedance analysis (BIA). In addition, appetite, inflammation, muscle strength, fatigue, quality of life, and survival were measured, and associations with cachexia were explored. Included were 241 patients with advanced cancer of the lung (36%), colon/rectum (31%), prostate (18%), or breast (15%). Mean age was 64 ± 10 years; 54% was male. Prevalence of low muscle mass was as follows: 13% with MUAMA, 59% with CT, and 93% with BIA. In turn, the prevalence of cachexia was 37, 43, and 48%, whereby weight loss >5% was the most prominent component of being defined cachectic. Irrespective of type of muscle measurement, patients with cachexia presented more often with anorexia, inflammation, low muscle strength, and fatigue and had lower quality of life. Patients with cachexia had worse overall survival compared with patients without cachexia: HRs 2.00 (1.42-2.83) with MUAMA, 1.64 (1.15-2.34) with CT, and 1.50 (1.05-2.14) with BIA. Although the prevalence of low muscle mass in patients with cancer depended largely on the type of muscle measurement, this had little influence on the diagnosis of cancer cachexia (as the majority of patients was already defined cachectic based on weight loss). New studies are warranted to further elucidate the additional role of muscle measurements in the diagnosis of cachexia and the association with clinical outcomes. © 2017 The Authors

  4. Skeletal muscle mass and exercise performance in stable ambulatory patients with heart failure.

    PubMed

    Lang, C C; Chomsky, D B; Rayos, G; Yeoh, T K; Wilson, J R

    1997-01-01

    The purpose of this study was to determine whether skeletal muscle atrophy limits the maximal exercise capacity of stable ambulatory patients with heart failure. Body composition and maximal exercise capacity were measured in 100 stable ambulatory patients with heart failure. Body composition was assessed by using dual-energy X-ray absorption. Peak exercise oxygen consumption (VO2peak) and the anaerobic threshold were measured by using a Naughton treadmill protocol and a Medical Graphics CardioO2 System. VO2peak averaged 13.4 +/- 3.3 ml.min-1.kg-1 or 43 +/- 12% of normal. Lean body mass averaged 52.9 +/- 10.5 kg and leg lean mass 16.5 +/- 3.6 kg. Leg lean mass correlated linearly with VO2peak (r = 0.68, P < 0.01), suggesting that exercise performance is influences by skeletal muscle mass. However, lean body mass was comparable to levels noted in 1,584 normal control subjects, suggesting no decrease in muscle mass. Leg muscle mass was comparable to levels noted in 34 normal control subjects, further supporting this conclusion. These findings suggest that exercise intolerance in stable ambulatory patients with heart failure is not due to skeletal muscle atrophy.

  5. Relation between systemic inflammatory markers, peripheral muscle mass, and strength in limb muscles in stable COPD patients.

    PubMed

    Ferrari, Renata; Caram, Laura M O; Faganello, Marcia M; Sanchez, Fernanda F; Tanni, Suzana E; Godoy, Irma

    2015-01-01

    The aim of this study was to investigate the association between systemic inflammatory mediators and peripheral muscle mass and strength in COPD patients. Fifty-five patients (69% male; age: 64±9 years) with mild/very severe COPD (defined as forced expiratory volume in the first second [FEV1] =54%±23%) were evaluated. We evaluated serum concentrations of IL-8, CRP, and TNF-α. Peripheral muscle mass was evaluated by computerized tomography (CT); midthigh cross-sectional muscle area (MTCSA) and midarm cross-sectional muscle area (MACSA) were obtained. Quadriceps, triceps, and biceps strength were assessed through the determination of the one-repetition maximum. The multiple regression results, adjusted for age, sex, and FEV1%, showed positive significant association between MTCSA and leg extension (0.35 [0.16, 0.55]; P=0.001), between MACSA and triceps pulley (0.45 [0.31, 0.58]; P=0.001), and between MACSA and biceps curl (0.34 [0.22, 0.47]; P=0.001). Plasma TNF-α was negatively associated with leg extension (-3.09 [-5.99, -0.18]; P=0.04) and triceps pulley (-1.31 [-2.35, -0.28]; P=0.01), while plasma CRP presented negative association with biceps curl (-0.06 [-0.11, -0.01]; P=0.02). Our results showed negative association between peripheral muscle mass (evaluated by CT) and muscle strength and that systemic inflammation has a negative influence in the strength of specific groups of muscles in individuals with stable COPD. This is the first study showing association between systemic inflammatory markers and strength in upper limb muscles.

  6. Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans

    PubMed Central

    Walker, Ann C.; O'Connor-Semmes, Robin L.; Leonard, Michael S.; Miller, Ram R.; Stimpson, Stephen A.; Turner, Scott M.; Ravussin, Eric; Cefalu, William T.; Hellerstein, Marc K.; Evans, William J.

    2014-01-01

    Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19–30 yr, 70–84 yr), 15 postmenopausal women (51–62 yr, 70–84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. PMID:24764133

  7. Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans.

    PubMed

    Clark, Richard V; Walker, Ann C; O'Connor-Semmes, Robin L; Leonard, Michael S; Miller, Ram R; Stimpson, Stephen A; Turner, Scott M; Ravussin, Eric; Cefalu, William T; Hellerstein, Marc K; Evans, William J

    2014-06-15

    Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19-30 yr, 70-84 yr), 15 postmenopausal women (51-62 yr, 70-84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA. Copyright © 2014 the American Physiological Society.

  8. High risk of malnutrition is associated with low muscle mass in older hospitalized patients - a prospective cohort study.

    PubMed

    Pierik, Vincent D; Meskers, Carel G M; Van Ancum, Jeanine M; Numans, Siger T; Verlaan, Sjors; Scheerman, Kira; Kruizinga, Roeliene C; Maier, Andrea B

    2017-06-05

    Malnutrition, low muscle strength and muscle mass are highly prevalent in older hospitalized patients and associated with adverse outcomes. Malnutrition may be a risk factor for developing low muscle mass. We aimed to investigate the association between the risk of malnutrition and 1) muscle strength and muscle mass at admission and 2) the change of muscle strength and muscle mass during hospitalization in older patients. The EMPOWER study included 378 patients aged seventy years or older who were acutely or electively admitted to four different wards of an academic teaching hospital in Amsterdam. Patients were grouped into low risk of malnutrition and high risk of malnutrition based on the Short Nutritional Assessment Questionnaire (SNAQ) score and were assessed for hand grip strength and muscle mass using hand held dynamometry respectively bioelectrical impedance analysis (BIA) within 48 h after admission and at day seven, or earlier at the day of discharge. Muscle mass was expressed as skeletal muscle mass, appendicular lean mass, fat free mass and the skeletal muscle index. The mean age of the patients was 79.7 years (SD 6.39), 48.9% were female. At admission, being at high risk of malnutrition was significantly associated with lower muscle mass (Odds Ratio, 95% CI, 0.90, 0.85-0.96), but not with muscle strength. Muscle strength and muscle mass did not change significantly during hospitalization in both groups. In older hospitalized patients, a high risk of malnutrition is associated with lower muscle mass at admission, but not with muscle strength nor with change of either muscle strength or muscle mass during hospitalization.

  9. Spreading out Muscle Mass within a Hill-Type Model: A Computer Simulation Study

    PubMed Central

    Günther, Michael; Röhrle, Oliver; Haeufle, Daniel F. B.; Schmitt, Syn

    2012-01-01

    It is state of the art that muscle contraction dynamics is adequately described by a hyperbolic relation between muscle force and contraction velocity (Hill relation), thereby neglecting muscle internal mass inertia (first-order dynamics). Accordingly, the vast majority of modelling approaches also neglect muscle internal inertia. Assuming that such first-order contraction dynamics yet interacts with muscle internal mass distribution, this study investigates two questions: (i) what is the time scale on which the muscle responds to a force step? (ii) How does this response scale with muscle design parameters? Thereto, we simulated accelerated contractions of alternating sequences of Hill-type contractile elements and point masses. We found that in a typical small muscle the force levels off after about 0.2 ms, contraction velocity after about 0.5 ms. In an upscaled version representing bigger mammals' muscles, the force levels off after about 20 ms, and the theoretically expected maximum contraction velocity is not reached. We conclude (i) that it may be indispensable to introduce second-order contributions into muscle models to understand high-frequency muscle responses, particularly in bigger muscles. Additionally, (ii) constructing more elaborate measuring devices seems to be worthwhile to distinguish viscoelastic and inertia properties in rapid contractile responses of muscles. PMID:23227110

  10. Relation between muscle mass, motor units and type of training in master athletes.

    PubMed

    Drey, Michael; Sieber, Cornel C; Degens, Hans; McPhee, Jamie; Korhonen, Marko T; Müller, Klaus; Ganse, Bergita; Rittweger, Jörn

    2016-01-01

    The aim of this study was to measure the number of motor units and muscle mass in power-trained and endurance-trained master athletes compared with community-dwelling older adults. Seventy-five master athletes (52 power- and 23 endurance-trained athletes) were recruited at the 2012 European Veteran Athletics Championships in Zittau (Germany). One hundred and forty-nine community-dwelling older adults served as controls. In all participants, the motor unit number index (MUNIX) in the hypothenar muscle and whole body muscle mass was determined by bioelectrical impedance analysis (BIA). In both male and female master athletes, there were significant negative correlations between age and muscle mass (female: r = -0·510, P = 0·002; male: r = -0·714, P<0·001). Master athletes showed a weak correlation (r = -0·295, P = 0·010) between MUNIX and age. Master athletes exhibited significantly higher values than the control group with regard to both muscle mass (P = 0·002) and motor units (P = 0·004). Subanalysis showed that only power trained master athletes had both a larger muscle mass (P<0·001) and a higher MUNIX (P = 0·014) than the control group. Among the master athletes, power-trained athletes had a larger (P<0·001) muscle mass than endurance-trained athletes. The present data of master athletes are compatible with the hypothesis of an age-related decline in whole body muscle mass and motor units. Nevertheless, the data suggest that the master athletes' high level of physical activity may protect motoneurons. In addition, power training seems to have a positive effect on muscle mass and could therefore be an effective method of training to prevent sarcopenia. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  11. Muscle Activation During Exercise in Severe Acute Hypoxia: Role of Absolute and Relative Intensity

    PubMed Central

    Torres-Peralta, Rafael; Losa-Reyna, José; González-Izal, Miriam; Perez-Suarez, Ismael; Calle-Herrero, Jaime; Izquierdo, Mikel

    2014-01-01

    Abstract Torres-Peralta, Rafael, José Losa-Reyna, Miriam González-Izal, Ismael Perez-Suarez, Jaime Calle-Herrero, Mikel Izquierdo, and José A.L. Calbet. Muscle activation during exercise in severe acute hypoxia: Role of absolute and relative intensity. High Alt Med Biol 15:472–482, 2014.—The aim of this study was to determine the influence of severe acute hypoxia on muscle activation during whole body dynamic exercise. Eleven young men performed four incremental cycle ergometer tests to exhaustion breathing normoxic (FIo2=0.21, two tests) or hypoxic gas (FIo2=0.108, two tests). Surface electromyography (EMG) activities of rectus femoris (RF), vastus medialis (VL), vastus lateralis (VL), and biceps femoris (BF) were recorded. The two normoxic and the two hypoxic tests were averaged to reduce EMG variability. Peak Vo2 was 34% lower in hypoxia than in normoxia (p<0.05). The EMG root mean square (RMS) increased with exercise intensity in all muscles (p<0.05), with greater effect in hypoxia than in normoxia in the RF and VM (p<0.05), and a similar trend in VL (p=0.10). At the same relative intensity, the RMS was greater in normoxia than in hypoxia in RF, VL, and BF (p<0.05), with a similar trend in VM (p=0.08). Median frequency increased with exercise intensity (p<0.05), and was higher in hypoxia than in normoxia in VL (p<0.05). Muscle contraction burst duration increased with exercise intensity in VM and VL (p<0.05), without clear effects of FIo2. No significant FIo2 effects on frequency domain indices were observed when compared at the same relative intensity. In conclusion, muscle activation during whole body exercise increases almost linearly with exercise intensity, following a muscle-specific pattern, which is adjusted depending on the FIo2 and the relative intensity of exercise. Both VL and VM are increasingly involved in power output generation with the increase of intensity and the reduction in FIo2. PMID:25225839

  12. Body Mass Normalization for Lateral Abdominal Muscle Thickness Measurements in Adolescent Athletes.

    PubMed

    Linek, Pawel

    2017-09-01

    To determine the value of allometric parameters for ultrasound measurements of the oblique external (OE), oblique internal (OI), and transversus abdominis (TrA) muscles in adolescent athletes. The allometric parameter is the slope of the linear regression line between the log-transformed body mass and log-transformed muscle size measurement. The study included 114 male adolescent football players between the ages of 10 and 19 years. All individuals with no surgical procedures performed on the trunk area and who had played a sport for at least 2 years were included. A real-time B-mode ultrasound scanner with a linear array transducer was used to obtain images of the lateral abdominal muscles from both sides of the body. A stabilometric platform was used to assess the body mass value. The correlations between body mass and the OE, OI, and TrA muscle thicknesses were r = 0.73, r = 0.79, and r = 0.64, respectively (in all cases, P < .0001). The allometric parameters were 0.77 for the OE, 0.67 for the OI, and 0.61 for the TrA. Using these parameters, no significant correlations were found between body mass and the allometric-scaled thickness of the lateral abdominal muscles. Significant positive correlations exist between body mass and lateral abdominal muscle thickness in adolescent athletes. Therefore, it is reasonable to advise that the values of the allometric parameters for the OE, OI, and TrA muscles obtained in this study should be used, and the allometric-scaled thicknesses of those muscles should be analyzed in future research on adolescent athletes. © 2017 by the American Institute of Ultrasound in Medicine.

  13. [Contractile properties of skeletal muscles of rats after flight on "Kosmos-1887"].

    PubMed

    Oganov, V S; Skuratova, S A; Murashko, L M

    1991-01-01

    Contractile properties of skeletal muscles of rats were investigated using glycerinated muscle preparations that were obtained from Cosmos-1887 animals flown for 13 days (plus 2 days on the ground) and from rats that remained hypokinetic for 13 days on the ground. In the flow rats, the absolute mass of postural muscles remained unchanged while their relative mass increased; this may be attributed to their enhanced hydration which developed during the first 2 days after landing. Strength losses of the postural muscles were less significant than after previous flights. Comparison of the Cosmos-1887 and hypokinesia control data has shown that even 2-day exposure to 1 G after 13-day flight can modify drastically flight-induced changes.

  14. The orbit of Phi Cygni measured with long-baseline optical interferometry - Component masses and absolute magnitudes

    NASA Technical Reports Server (NTRS)

    Armstrong, J. T.; Hummel, C. A.; Quirrenbach, A.; Buscher, D. F.; Mozurkewich, D.; Vivekanand, M.; Simon, R. S.; Denison, C. S.; Johnston, K. J.; Pan, X.-P.

    1992-01-01

    The orbit of the double-lined spectroscopic binary Phi Cygni, the distance to the system, and the masses and absolute magnitudes of its components are presented via measurements with the Mar III Optical Interferometer. On the basis of a reexamination of the spectroscopic data of Rach & Herbig (1961), the values and uncertainties are adopted for the period and the projected semimajor axes from the present fit to the spectroscopic data and the values of the remaining elements from the present fit to the Mark III data. The elements of the true orbit are derived, and the masses and absolute magnitudes of the components, and the distance to the system are calculated.

  15. Myoglobin plasma level related to muscle mass and fiber composition: a clinical marker of muscle wasting?

    PubMed

    Weber, Marc-André; Kinscherf, Ralf; Krakowski-Roosen, Holger; Aulmann, Michael; Renk, Hanna; Künkele, Annette; Edler, Lutz; Kauczor, Hans-Ulrich; Hildebrandt, Wulf

    2007-08-01

    Progressive muscle wasting is a central feature of cancer-related cachexia and has been recognized as a determinant of poor prognosis and quality of life. However, until now, no easily assessable clinical marker exists that allows to predict or to track muscle wasting. The present study evaluated the potential of myoglobin (MG) plasma levels to indicate wasting of large locomotor muscles and, moreover, to reflect the loss of MG-rich fiber types, which are most relevant for daily performance. In 17 cancer-cachectic patients (weight loss 22%) and 27 age- and gender-matched healthy controls, we determined plasma levels of MG and creatine kinase (CK), maximal quadriceps muscle cross-sectional area (CSA) by magnetic resonance imaging, muscle morphology and fiber composition in biopsies from the vastus lateralis muscle, body cell mass (BCM) by impedance technique as well as maximal oxygen uptake (VO(2)max). In cachectic patients, plasma MG, muscle CSA, BCM, and VO(2)max were 30-35% below control levels. MG showed a significant positive correlation to total muscle CSA (r = 0.65, p < 0.001) and to the CSA fraction formed by type 1 and 2a fibers (r = 0.80, p < 0.001). However, when adjusted for body height and age by multiple regression, MG yielded a largely improved prediction of total CSA (multiple r = 0.83, p < 0.001) and of fiber type 1 and 2a CSA (multiple r = 0.89, p < 0.001). The correlations between CK and these muscle parameters were weaker, and elevated CK values were observed in 20% of control subjects despite a prior abstinence from exercise for 5 days. In conclusion, plasma MG, when adjusted for anthropometric parameters unaffected by weight, may be considered as a novel marker of muscle mass (CSA) indicating best the mass of MG-rich type 1 and 2a fibers as well as VO(2)max as an important functional readout. CK plasma levels appear to be less reliable because prolonged increases are observed in even subclinical myopathies or after exercise. Notably, cancer

  16. Association of low back pain with muscle stiffness and muscle mass of the lumbar back muscles, and sagittal spinal alignment in young and middle-aged medical workers.

    PubMed

    Masaki, Mitsuhiro; Aoyama, Tomoki; Murakami, Takashi; Yanase, Ko; Ji, Xiang; Tateuchi, Hiroshige; Ichihashi, Noriaki

    2017-11-01

    Muscle stiffness of the lumbar back muscles in low back pain (LBP) patients has not been clearly elucidated because quantitative assessment of the stiffness of individual muscles was conventionally difficult. This study aimed to examine the association of LBP with muscle stiffness assessed using ultrasonic shear wave elastography (SWE) and muscle mass of the lumbar back muscle, and spinal alignment in young and middle-aged medical workers. The study comprised 23 asymptomatic medical workers [control (CTR) group] and 9 medical workers with LBP (LBP group). Muscle stiffness and mass of the lumbar back muscles (lumbar erector spinae, multifidus, and quadratus lumborum) in the prone position were measured using ultrasonic SWE. Sagittal spinal alignment in the standing and prone positions was measured using a Spinal Mouse. The association with LBP was investigated by multiple logistic regression analysis with a forward selection method. The analysis was conducted using the shear elastic modulus and muscle thickness of the lumbar back muscles, and spinal alignment, age, body height, body weight, and sex as independent variables. Multiple logistic regression analysis showed that muscle stiffness of the lumbar multifidus muscle and body height were significant and independent determinants of LBP, but that muscle mass and spinal alignment were not. Muscle stiffness of the lumbar multifidus muscle in the LBP group was significantly higher than that in the CTR group. The results of this study suggest that LBP is associated with muscle stiffness of the lumbar multifidus muscle in young and middle-aged medical workers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Ultrasound-Based Detection of Low Muscle Mass for Diagnosis of Sarcopenia in Older Adults.

    PubMed

    Minetto, Marco A; Caresio, Cristina; Menapace, Tommaso; Hajdarevic, Arnel; Marchini, Andrea; Molinari, Filippo; Maffiuletti, Nicola A

    2016-05-01

    To establish muscle-specific cut-off values for ultrasound-based detection of low muscle mass, and to assess its prevalence in a population of frail older subjects when applying the cut-points of different muscles and those of different sarcopenic indices. Cross-sectional study. Geriatric outpatient clinic and clinical research laboratory. A total of 44 older adults (30 women and 14 men, mean age 82 years, range 67-93 years) and 60 younger individuals (30 women and 30 men, mean age 26 years, range 20-36 years) participated. Body composition and thickness of 4 lower limb muscles (rectus femoris, vastus lateralis, tibialis anterior, medial gastrocnemius) were respectively assessed by bioelectrical impedance analysis (BIA) and ultrasonography. Site-specific cut-points for ultrasound-based assessment of low muscle mass (muscle thickness values 2 standard deviations below the gender-specific means of our sample of younger subjects) and comparative prevalence rates of low muscle mass. The following site-specific cut-points for muscle thickness were identified: rectus femoris: 20 mm in men and 16 mm in women; vastus lateralis: 17 mm in men and 15 mm in women; tibialis anterior: 23 mm in men and 22 mm in women; and medial gastrocnemius: 13 mm in both men and women. The prevalence of low muscle mass in older adults was highly dependent on the muscle being investigated; it varied from 86% for thigh muscles to 30% for leg muscles. Moreover, the prevalence of low muscle mass was highly dependent on the applied diagnostic criterion and on the adopted cut-off value; it ranged from 2% to 75% for different BIA-derived criteria. We suggest that muscle ultrasonography provides physiatrists with a practical and accurate tool for identifying individuals with low muscle mass. However, the usability of cut-off values established in our group of healthy younger subjects of white ethnicity to identify low muscle mass in older individuals of different ethnic groups remains to be

  18. Effects of Resveratrol on the Recovery of Muscle Mass Following Disuse in the Plantaris Muscle of Aged Rats

    PubMed Central

    Bennett, Brian T.; Mohamed, Junaith S.; Alway, Stephen E.

    2013-01-01

    Aging is associated with poor skeletal muscle regenerative ability following extended periods of hospitalization and other forms of muscular disuse. Resveratrol (3,5,4’-trihydroxystilbene) is a natural phytoalexin which has been shown in skeletal muscle to improve oxidative stress levels in muscles of aged rats. As muscle disuse and reloading after disuse increases oxidative stress, we hypothesized that resveratrol supplementation would improve muscle regeneration after disuse. A total of thirty-six male Fisher 344 × Brown Norway rats (32 mo.) were treated with either a water vehicle or resveratrol via oral gavage. The animals received hindlimb suspension for 14 days. Thereafter, they were either sacrificed or allowed an additional 14 day period of cage ambulation during reloading. A total of six rats from the vehicle and the resveratrol treated groups were used for the hindlimb suspension and recovery protocols. Furthermore, two groups of 6 vehicle treated animals maintained normal ambulation throughout the experiment, and were used as control animals for the hindlimb suspension and reloading groups. The data show that resveratrol supplementation was unable to attenuate the decreases in plantaris muscle wet weight during hindlimb suspension but it improved muscle mass during reloading after hindlimb suspension. Although resveratrol did not prevent fiber atrophy during the period of disuse, it increased the fiber cross sectional area of type IIA and IIB fibers in response to reloading after hindlimb suspension. There was a modest enhancement of myogenic precursor cell proliferation in resveratrol-treated muscles after reloading, but this failed to reach statistical significance. The resveratrol-associated improvement in type II fiber size and muscle mass recovery after disuse may have been due to decreases in the abundance of pro-apoptotic proteins Bax, cleaved caspase 3 and cleaved caspase 9 in reloaded muscles. Resveratrol appears to have modest therapeutic

  19. Sexual dimorphism of extensor carpi radialis muscle size, isometric force, relaxation rate and stamina during the breeding season of the frog Rana temporaria Linnaeus 1758.

    PubMed

    Navas, Carlos A; James, Rob S

    2007-02-01

    Mating success of individual male frogs within explosive breeding species can depend on their ability to compete for a mate and to hold onto that mate during amplexus. Such importance of amplexus has resulted in the evolution of sexual dimorphism in the morphology and contractile characteristics of the anuran forelimb muscles used during amplexus. The aims of our study were to use an explosive breeding frog (Rana temporaria) during the breeding season to compare extensor carpi radialis (ECR) muscle length, mass, isometric activation times, relaxation times, absolute force, relative force (stress) and fatigue between male and female frogs. We found that ECR muscle mass and length were greater (tenfold and 1.4-fold, respectively), absolute tetanic muscle force and relative tetanic force (stress) were greater (16-fold and 2.2-fold, respectively) and relaxation times were slower in males than in females. Male ECR muscles incompletely relaxed during fatigue tests and showed less fatigue than female muscles. These sex differences are likely to be beneficial to the male frogs in allowing them to produce relatively high absolute muscle forces for prolonged periods of time to hold onto their mate during amplexus.

  20. Decreased muscle mass in Korean subjects with intracranial arterial stenosis: The Kangbuk Samsung Health Study.

    PubMed

    Jung, Ho-Jung; Jung, Hwanseok; Lee, Taeyoung; Kim, Jongho; Park, Jongsin; Kim, Hacsoo; Cho, Junghwan; Lee, Won-Young; Park, Sung-Woo; Rhee, Eun-Jung; Oh, Hyung-Geun

    2017-01-01

    Intracranial arterial stenosis (ICAS) is a common cause of ischemic stroke in Asians. Decreased muscle mass is one of the major causes of chronic disease in adults. The purpose of this study was to analyze the relationship between muscle mass and ICAS in Korean adults. For this study, we selected a total of 10,530 participants (mean age, 43.3 years; 8558 men) in a health screening program, for whom transcranial Doppler (TCD) ultrasound was used to detect >50% ICAS based on criteria modified from the stroke outcomes and neuroimaging of intracranial atherosclerosis trial. Body composition was evaluated by bioelectrical impedance analysis (BIA). Skeletal muscle index (SMI) was calculated with muscle mass/weight (kg) * 100. Among the total patient population, 322 (3.1%) subjects had ICAS. Subjects with ICAS were older, and had higher mean values for fasting glucose, body mass index and blood pressure compared with those without ICAS. Subjects with ICAS had significantly lower muscle mass, SMI and higher percent body fat compared with those without ICAS. In logistic regression analysis, the subjects in the highest tertile of muscle mass had the lowest odds ratio for ICAS with the lowest tertile group of muscle mass as the reference group even after adjusting for age, systolic blood pressure, fasting blood glucose, sex, smoking and exercise (OR 0.650, 95% CI 0.442-0.955). Subjects with ICAS had significantly decreased muscle mass compared with those without ICAS in Korean adults. The risk for ICAS was lower in subjects with higher muscle mass. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Establishing Ion Ratio Thresholds Based on Absolute Peak Area for Absolute Protein Quantification using Protein Cleavage Isotope Dilution Mass Spectrometry

    PubMed Central

    Loziuk, Philip L.; Sederoff, Ronald R.; Chiang, Vincent L.; Muddiman, David C.

    2014-01-01

    Quantitative mass spectrometry has become central to the field of proteomics and metabolomics. Selected reaction monitoring is a widely used method for the absolute quantification of proteins and metabolites. This method renders high specificity using several product ions measured simultaneously. With growing interest in quantification of molecular species in complex biological samples, confident identification and quantitation has been of particular concern. A method to confirm purity or contamination of product ion spectra has become necessary for achieving accurate and precise quantification. Ion abundance ratio assessments were introduced to alleviate some of these issues. Ion abundance ratios are based on the consistent relative abundance (RA) of specific product ions with respect to the total abundance of all product ions. To date, no standardized method of implementing ion abundance ratios has been established. Thresholds by which product ion contamination is confirmed vary widely and are often arbitrary. This study sought to establish criteria by which the relative abundance of product ions can be evaluated in an absolute quantification experiment. These findings suggest that evaluation of the absolute ion abundance for any given transition is necessary in order to effectively implement RA thresholds. Overall, the variation of the RA value was observed to be relatively constant beyond an absolute threshold ion abundance. Finally, these RA values were observed to fluctuate significantly over a 3 year period, suggesting that these values should be assessed as close as possible to the time at which data is collected for quantification. PMID:25154770

  2. PGC-1α is important for maintaining the balance of muscle mass and myofiber types in unloaded muscle atrophy

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoping; He, Jian; Wang, Fei; Zhang, Peng; Liu, Hongju; Li, Wenjiong

    2016-07-01

    PGC-1α, a transcriptional co-activator, has been shown mainly to determine the development of oxidative myofibers in skeletal muscle. However, whether PGC-1α functions to regulate the unloaded muscle atrophy and composition of myofiber types keeps unclear. MCK-PGC-1α overexpression transgenic mice (TG) and its wild type littermates (WT) were subjected to hindlimb unloading (HU) and induced unloaded muscle atrophy. After 14 days of HU, the mass of gastrocnemius, soleus, and plantaris muscles in WT mice decreased 17.9%, 28.2%, and 14.8%, respectively (P<0.01), compared with ground weight-bearing control muscles. PGC-1α transgenic mice showed a 14.0% (P<0.05), 20.4% (P<0.01), 11.8% decrease in gastrocnemius, soleus, and plantaris muscles mass after HU. To further confirm the effect of PGC-1α over-expression on the muscle mass loss under HU, change rate of muscle-body weight ratio was calculated, and the results indicated that the reduction of change rate of muscle-body weight ratio in PGC-1α transgenic gastrocnemius and soleus was significantly less than in WT mice (P<0.01). Moreover, in TG mice compared to WT mice there were significantly less reduction rate of slow-twitch myofiber MHC-I and MHC-IIa (MHC-I, -3.0±0.2% vs -14.9±4.2%, p<0.01, MHC-IIa, -3.5±2.7% vs -6.2±3.7%, p<0.01 ), while there was significantly less induction rate of fast-twitch myofiber MHC-IIb (MHC-IIb, +0.6±0.6% vs +3.7±2.9%, p<0.01 ). The real-time PCR and Western blot analysis confirmed that PGC-1α overexpression mice markedly rescued the muscle atrophy and myofiber switching from oxidative to glycolytic associated with a decrease in pSmad3 level after 14 days of HU. Importantly, overexpression of PGC-1α in C2C12 myoblasts protected PGC-1α-transfected myotubes from atrophy in vitro and the effect could be partially blocked by inducing pSmad3 with constitutively activated Smad3(C.A. smad3) transfection. Therefore, this study demonstrated a novel role and mechanism for PGC-1α in

  3. Pitfalls in the measurement of muscle mass: a need for a reference standard

    PubMed Central

    Landi, Francesco; Cesari, Matteo; Fielding, Roger A.; Visser, Marjolein; Engelke, Klaus; Maggi, Stefania; Dennison, Elaine; Al‐Daghri, Nasser M.; Allepaerts, Sophie; Bauer, Jurgen; Bautmans, Ivan; Brandi, Maria Luisa; Bruyère, Olivier; Cederholm, Tommy; Cerreta, Francesca; Cherubini, Antonio; Cooper, Cyrus; Cruz‐Jentoft, Alphonso; McCloskey, Eugene; Dawson‐Hughes, Bess; Kaufman, Jean‐Marc; Laslop, Andrea; Petermans, Jean; Reginster, Jean‐Yves; Rizzoli, René; Robinson, Sian; Rolland, Yves; Rueda, Ricardo; Vellas, Bruno; Kanis, John A.

    2018-01-01

    Abstract Background All proposed definitions of sarcopenia include the measurement of muscle mass, but the techniques and threshold values used vary. Indeed, the literature does not establish consensus on the best technique for measuring lean body mass. Thus, the objective measurement of sarcopenia is hampered by limitations intrinsic to assessment tools. The aim of this study was to review the methods to assess muscle mass and to reach consensus on the development of a reference standard. Methods Literature reviews were performed by members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis working group on frailty and sarcopenia. Face‐to‐face meetings were organized for the whole group to make amendments and discuss further recommendations. Results A wide range of techniques can be used to assess muscle mass. Cost, availability, and ease of use can determine whether the techniques are better suited to clinical practice or are more useful for research. No one technique subserves all requirements but dual energy X‐ray absorptiometry could be considered as a reference standard (but not a gold standard) for measuring muscle lean body mass. Conclusions Based on the feasibility, accuracy, safety, and low cost, dual energy X‐ray absorptiometry can be considered as the reference standard for measuring muscle mass. PMID:29349935

  4. Pitfalls in the measurement of muscle mass: a need for a reference standard.

    PubMed

    Buckinx, Fanny; Landi, Francesco; Cesari, Matteo; Fielding, Roger A; Visser, Marjolein; Engelke, Klaus; Maggi, Stefania; Dennison, Elaine; Al-Daghri, Nasser M; Allepaerts, Sophie; Bauer, Jurgen; Bautmans, Ivan; Brandi, Maria Luisa; Bruyère, Olivier; Cederholm, Tommy; Cerreta, Francesca; Cherubini, Antonio; Cooper, Cyrus; Cruz-Jentoft, Alphonso; McCloskey, Eugene; Dawson-Hughes, Bess; Kaufman, Jean-Marc; Laslop, Andrea; Petermans, Jean; Reginster, Jean-Yves; Rizzoli, René; Robinson, Sian; Rolland, Yves; Rueda, Ricardo; Vellas, Bruno; Kanis, John A

    2018-04-01

    All proposed definitions of sarcopenia include the measurement of muscle mass, but the techniques and threshold values used vary. Indeed, the literature does not establish consensus on the best technique for measuring lean body mass. Thus, the objective measurement of sarcopenia is hampered by limitations intrinsic to assessment tools. The aim of this study was to review the methods to assess muscle mass and to reach consensus on the development of a reference standard. Literature reviews were performed by members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis working group on frailty and sarcopenia. Face-to-face meetings were organized for the whole group to make amendments and discuss further recommendations. A wide range of techniques can be used to assess muscle mass. Cost, availability, and ease of use can determine whether the techniques are better suited to clinical practice or are more useful for research. No one technique subserves all requirements but dual energy X-ray absorptiometry could be considered as a reference standard (but not a gold standard) for measuring muscle lean body mass. Based on the feasibility, accuracy, safety, and low cost, dual energy X-ray absorptiometry can be considered as the reference standard for measuring muscle mass. © 2018 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  5. Optimized dietary strategies to protect skeletal muscle mass during periods of unavoidable energy deficit.

    PubMed

    Pasiakos, Stefan M; Margolis, Lee M; Orr, Jeb S

    2015-04-01

    Interactions between dietary protein and energy balance on the regulation of human skeletal muscle protein turnover are not well described. A dietary protein intake above the recommended dietary allowance during energy balance typically enhances nitrogen retention and up-regulates muscle protein synthesis, which in turn may promote positive protein balance and skeletal muscle accretion. Recent studies show that during energy deficit, muscle protein synthesis is down-regulated with concomitant increases in ubiquitin proteasome-mediated muscle proteolysis and nitrogen excretion, reflecting the loss of skeletal muscle mass. However, consuming high-protein diets (1.6-2.4 g/kg per day), or high-quality, protein-based meals (15-30 g whey) during energy deficit attenuates intracellular proteolysis, restores muscle protein synthesis, and mitigates skeletal muscle loss. These findings are particularly important for physically active, normal-weight individuals because attenuating the extent to which skeletal muscle mass is lost during energy deficit could prevent decrements in performance, reduce injury risk, and facilitate recovery. This article reviews the relationship between energy status, protein intake, and muscle protein turnover, and explores future research directives designed to protect skeletal muscle mass in physically active, normal-weight adults. © FASEB.

  6. Skeletal muscle mass and risk of death in an elderly population.

    PubMed

    Chuang, S-Y; Chang, H-Y; Lee, M-S; Chia-Yu Chen, R; Pan, W-H

    2014-07-01

    Body mass index (BMI) has a U-shaped relationship with mortality among the elderly, in contrast to the general adult population. Skeletal muscle mass may be more appropriate than BMI for classifying mortality risk among the elderly. We investigated the relationship between skeletal muscle mass and mortality among elderly Chinese persons. A total of 1512 elderly from the Nutrition and Health Survey in Taiwanese Elderly (1999-2000) was enrolled, and the survival status was followed using data from the National Death Registry. The skeletal muscle mass index (SMMI) was calculated by dividing skeletal muscle mass by height in meters squared. The Cox proportional hazard model was used to estimate the association between SMMI and mortality. During the follow-up (average time: 7.9 years), one-third elderly died (n = 506) by any cause and 25% of them was cardiovascular mortality (ICD-9-CM: between 390 and 459). The total mortality and cardiovascular mortality were 4.23 and 1.07 per 100 person-years. Elderly participants with the lowest SMMI had the highest total mortality and cardiovascular mortality among the four quartiles (6.72, 3.76, 3.25 and 3.50 per 100 PY for total mortality; 1.81, 0.76, 0.87, 0.93 for cardiovascular mortality). Those with a low (1st quartile) SMMI had a 2-fold increase in total mortality (1.96; 1.63-2.35) and cardiovascular mortality (2.16; 1.51-3.08) risk compared to those with a normal [2nd, 3rd, or 4th quartile] SMMI. The threshold relationship between SMMI and mortality is contrast to the reverse J-shaped relationship between BMI and total mortality. Therefore, skeletal muscle mass measurement may be considered with a high priority to identify elderly individuals with a high mortality risk. Copyright © 2014. Published by Elsevier B.V.

  7. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

  8. Muscle mass, BMI, and mortality among adults in the United States: A population-based cohort study.

    PubMed

    Abramowitz, Matthew K; Hall, Charles B; Amodu, Afolarin; Sharma, Deep; Androga, Lagu; Hawkins, Meredith

    2018-01-01

    The level of body-mass index (BMI) associated with the lowest risk of death remains unclear. Although differences in muscle mass limit the utility of BMI as a measure of adiposity, no study has directly examined the effect of muscle mass on the BMI-mortality relationship. Body composition was measured by dual-energy x-ray absorptiometry in 11,687 participants of the National Health and Nutrition Examination Survey 1999-2004. Low muscle mass was defined using sex-specific thresholds of the appendicular skeletal muscle mass index (ASMI). Proportional hazards models were created to model associations with all-cause mortality. At any level of BMI ≥22, participants with low muscle mass had higher body fat percentage (%TBF), an increased likelihood of diabetes, and higher adjusted mortality than other participants. Increases in %TBF manifested as 30-40% smaller changes in BMI than were observed in participants with preserved muscle mass. Excluding participants with low muscle mass or adjustment for ASMI attenuated the risk associated with low BMI, magnified the risk associated with high BMI, and shifted downward the level of BMI associated with the lowest risk of death. Higher ASMI was independently associated with lower mortality. Effects were similar in never-smokers and ever-smokers. Additional adjustment for waist circumference eliminated the risk associated with higher BMI. Results were unchanged after excluding unintentional weight loss, chronic illness, early mortality, and participants performing muscle-strengthening exercises or recommended levels of physical activity. Muscle mass mediates associations of BMI with adiposity and mortality and is inversely associated with the risk of death. After accounting for muscle mass, the BMI associated with the greatest survival shifts downward toward the normal range. These results provide a concrete explanation for the obesity paradox.

  9. Muscle mass, BMI, and mortality among adults in the United States: A population-based cohort study

    PubMed Central

    Hall, Charles B.; Amodu, Afolarin; Sharma, Deep; Androga, Lagu; Hawkins, Meredith

    2018-01-01

    Background The level of body-mass index (BMI) associated with the lowest risk of death remains unclear. Although differences in muscle mass limit the utility of BMI as a measure of adiposity, no study has directly examined the effect of muscle mass on the BMI-mortality relationship. Methods Body composition was measured by dual-energy x-ray absorptiometry in 11,687 participants of the National Health and Nutrition Examination Survey 1999–2004. Low muscle mass was defined using sex-specific thresholds of the appendicular skeletal muscle mass index (ASMI). Proportional hazards models were created to model associations with all-cause mortality. Results At any level of BMI ≥22, participants with low muscle mass had higher body fat percentage (%TBF), an increased likelihood of diabetes, and higher adjusted mortality than other participants. Increases in %TBF manifested as 30–40% smaller changes in BMI than were observed in participants with preserved muscle mass. Excluding participants with low muscle mass or adjustment for ASMI attenuated the risk associated with low BMI, magnified the risk associated with high BMI, and shifted downward the level of BMI associated with the lowest risk of death. Higher ASMI was independently associated with lower mortality. Effects were similar in never-smokers and ever-smokers. Additional adjustment for waist circumference eliminated the risk associated with higher BMI. Results were unchanged after excluding unintentional weight loss, chronic illness, early mortality, and participants performing muscle-strengthening exercises or recommended levels of physical activity. Conclusions Muscle mass mediates associations of BMI with adiposity and mortality and is inversely associated with the risk of death. After accounting for muscle mass, the BMI associated with the greatest survival shifts downward toward the normal range. These results provide a concrete explanation for the obesity paradox. PMID:29641540

  10. No Change of Body Mass, Fat Mass, and Skeletal Muscle Mass in Ultraendurance Swimmers after 12 Hours of Swimming

    ERIC Educational Resources Information Center

    Knechtle, Beat; Knechtle, Patrizia; Kaul, Rene; Kohler, Gotz

    2009-01-01

    We evaluated whether ultraendurance swimmers suffer a change of body mass, fat mass, skeletal muscle mass, total body water, and specific gravity of urine during a 12-hr swim in 12 male Caucasian ultraswimmers. Proton nuclear magnetic resonance of urine samples before and after the race was performed to detect alanine, lactate, and…

  11. The association between the low muscle mass and osteoporosis in elderly Korean people.

    PubMed

    Kim, Sunyoung; Won, Chang Won; Kim, Byung Sung; Choi, Hyun Rim; Moon, Min Young

    2014-07-01

    The purpose of this study was to predict osteoporosis risk as decreasing muscle mass and to declare the cut-off value of low muscle mass in an elderly Korean population. This study was based on data from the 2008-2010 Korea National Health and Nutritional Examination Surveys (KNHANES). The subjects included 1,308 men and 1,171 women over 65 yr. Bone mineral density (BMD) and appendicular skeletal muscle (ASM) were measured by dual energy X-ray absorptiometry (DXA), and appendicular skeletal muscle was adjusted by height as a marker of sarcopenia. After confirming the correlation between low muscle mass and BMD, the best cut-off value of muscle mass to estimate osteoporosis was suggested through the receiver operating characteristic (ROC) curve. For both men and women, BMD correlated positively with low muscle mass when ASM/Ht(2) was used as a marker for sarcopenia. The ROC curve showed that ASM/Ht(2) was the best marker for osteoporosis at a cut-off value of 6.85 kg/m(2) for men and 5.96 kg/m(2) for women. When these cut-off values were used to determine sarcopenia, the risk of osteoporosis increased 4.14 times in men and 1.88 times in women. In particular, men (OR 2.12) with sarcopenia were more greatly affected than women (OR 1.15), even after adjusting for osteoporosis risk factors. In elderly Korean people, sarcopenia is positively correlated with BMD and there is a strong correlation between sarcopenia and osteoporosis with risk of bone fracture.

  12. Excessive loss of skeletal muscle mass in older adults with type 2 diabetes.

    PubMed

    Park, Seok Won; Goodpaster, Bret H; Lee, Jung Sun; Kuller, Lewis H; Boudreau, Robert; de Rekeneire, Nathalie; Harris, Tamara B; Kritchevsky, Stephen; Tylavsky, Frances A; Nevitt, Michael; Cho, Yong-wook; Newman, Anne B

    2009-11-01

    A loss of skeletal muscle mass is frequently observed in older adults. The aim of the study was to investigate the impact of type 2 diabetes on the changes in body composition, with particular interest in the skeletal muscle mass. We examined total body composition with dual-energy X-ray absorptiometry annually for 6 years in 2,675 older adults. We also measured mid-thigh muscle cross-sectional area (CSA) with computed tomography in year 1 and year 6. At baseline, 75-g oral glucose challenge tests were performed. Diagnosed diabetes (n = 402, 15.0%) was identified by self-report or use of hypoglycemic agents. Undiagnosed diabetes (n = 226, 8.4%) was defined by fasting plasma glucose (>or=7 mmol/l) or 2-h postchallenge plasma glucose (>or=11.1 mmol/l). Longitudinal regression models were fit to examine the effect of diabetes on the changes in body composition variables. Older adults with either diagnosed or undiagnosed type 2 diabetes showed excessive loss of appendicular lean mass and trunk fat mass compared with nondiabetic subjects. Thigh muscle CSA declined two times faster in older women with diabetes than their nondiabetic counterparts. These findings remained significant after adjusting for age, sex, race, clinic site, baseline BMI, weight change intention, and actual weight changes over time. Type 2 diabetes is associated with excessive loss of skeletal muscle and trunk fat mass in community-dwelling older adults. Older women with type 2 diabetes are at especially high risk for loss of skeletal muscle mass.

  13. The bone morphogenetic protein axis is a positive regulator of skeletal muscle mass

    PubMed Central

    Chen, Justin L.; Qian, Hongwei; Liu, Yingying; Bernardo, Bianca C.; Beyer, Claudia; Watt, Kevin I.; Thomson, Rachel E.; Connor, Timothy; Turner, Bradley J.; McMullen, Julie R.; Larsson, Lars; McGee, Sean L.; Harrison, Craig A.

    2013-01-01

    Although the canonical transforming growth factor β signaling pathway represses skeletal muscle growth and promotes muscle wasting, a role in muscle for the parallel bone morphogenetic protein (BMP) signaling pathway has not been defined. We report, for the first time, that the BMP pathway is a positive regulator of muscle mass. Increasing the expression of BMP7 or the activity of BMP receptors in muscles induced hypertrophy that was dependent on Smad1/5-mediated activation of mTOR signaling. In agreement, we observed that BMP signaling is augmented in models of muscle growth. Importantly, stimulation of BMP signaling is essential for conservation of muscle mass after disruption of the neuromuscular junction. Inhibiting the phosphorylation of Smad1/5 exacerbated denervation-induced muscle atrophy via an HDAC4-myogenin–dependent process, whereas increased BMP–Smad1/5 activity protected muscles from denervation-induced wasting. Our studies highlight a novel role for the BMP signaling pathway in promoting muscle growth and inhibiting muscle wasting, which may have significant implications for the development of therapeutics for neuromuscular disorders. PMID:24145169

  14. Body Mass Normalization for Ultrasound Measurements of Adolescent Lateral Abdominal Muscle Thickness.

    PubMed

    Linek, Pawel; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej

    2017-04-01

    The purpose of this study was to determine the value of the allometric parameter for ultrasound measurements of the thickness of the oblique external (OE), internal (OI), and transversus abdominis (TrA) muscles in the adolescent population. The allometric parameter is the slope of the linear regression line between the log transformed body mass and log transformed muscle size measurement. The study included 321 adolescents between the ages of 10 and 17, consisting of 160 boys and 161 girls. The participants were recruited from local schools and attended regular school classes at normal grade levels. All individuals with no signs of scoliosis (screening with use of a scoliometer), and no surgical procedures performed on the trunk area were included. A real-time ultrasound B-scanner with a linear array transducer was used to obtain images of the lateral abdominal muscles from both sides of the body. The correlation between body mass and the OE muscle was r = 0.69; the OI muscle r = 0.68; and the TrA muscle r = 0.53 (in all cases, P < .0001). The allometric parameter for the OE was 0.88296; the OI 0.718756; and the TrA 0.60986. Using these parameters, no significant correlations were found between body mass and the allometric-scaled thickness of the lateral abdominal muscles. Significant positive correlations exist between body mass and lateral abdominal muscle thickness assessed by ultrasound imaging. Therefore, it is reasonable to advise that the values of the allometric parameters for OE, OI, and TrA obtained in this study should be used in other studies performed on adolescents. © 2016 by the American Institute of Ultrasound in Medicine.

  15. Low muscle mass--tall and obese children a special genre of obesity.

    PubMed

    Ralt, Dina

    2007-01-01

    The prevalence of over-weight and obesity has increased markedly in the last two decades and vast international resources have been directed toward researching these issues. Obesity would appear to be a problem that is easy to resolve: just eat less and move more. However, this very common condition has turned out to be extremely troublesome, and in some cases even insolvable. A perspective is presented here suggesting that some of the insoluble cases of obesity are the result of an inborn condition of a very low muscle mass. The interplay between less muscle and more fat tissue is discussed from physiological and environmental perspectives with an emphasis on the early years of childhood. It is proposed that these interactions lead to bodily economic decisions sliding between thrift or prodigal strategies. The thrift strategy results not only in obesity and less physical activity but also in other maladies which the body is unable to manage. What leads to obesity (less muscle, more fat) in the medial population will result in morbid obesity when the children are short of muscle tissue from the start. Attempts to lessen the consequences of low muscle mass, which might be very difficult at adulthood, can be more fruitful if initiated at childhood. Early recognition of the ailment is thus crucial. Based on studies demonstrating a 'rivalry' between muscle build-up and height growth at childhood, it is postulated that among the both taller and more obese children the percentage of children with lower muscle mass will be significant. A survey of the height and BMI (Body Mass Index) of Israeli fifth graders supports this postulation. A special, body/muscle-building gymnastics program for children is suggested as a potential early intervention to partially prevent this type of almost irreversible ill progress of obesity.

  16. Decreased muscle mass is not an independent risk factor for metabolic syndrome in Korean population aged 70 or older.

    PubMed

    Koo, Hyung Suk; Kim, Moon Jong; Kim, Kwang-Min; Kim, Young-Sang

    2015-04-01

    The association of low muscle mass with cardiometabolic risks is still controversial. The aim of this study was to investigate the relationship between low muscle mass and metabolic syndrome (MetS) according to the various muscle mass indices and to evaluate the influence of muscle mass on MetS independent of fat mass. Cross-sectional study About 841 men and 1106 women aged 70 or older from Korea National Health and Nutrition Examination Survey 2008-2010 MEASUREMENTS: We used various muscle mass indices: appendicular skeletal muscle mass (ASM) divided by height squared (ASM/Ht(2) ), ASM divided by body weight (ASM/Wt) and ASM adjusted for height and fat mass (residual). Low muscle mass is defined as ASM/Ht(2) and ASM/Wt below 2 SD of the sex-specific mean for healthy young adults. The sex-specific lowest quintile of the distribution of the residual was regarded as low muscle mass. The prevalence of MetS was higher in the population with low muscle mass defined by ASM/Wt, but lower in those defined by ASM/Ht(2) . However, after stratification according to the central obesity, low muscle mass was barely related with MetS. Meanwhile, when both ASM and fat mass were included in a logistic regression model, the odds ratios of 1 SD change of ASM for MetS were 1·07 (0·85-1·34) for men and 1·24 (1·04-1·47) for women, respectively. The relationship between low muscle mass and MetS was different according to the various muscle mass indices. After controlling the influence of fat mass, decreased muscle mass was not an independent risk factor for MetS. © 2014 John Wiley & Sons Ltd.

  17. Creatine Supplementation and Skeletal Muscle Metabolism for Building Muscle Mass- Review of the Potential Mechanisms of Action.

    PubMed

    Farshidfar, Farnaz; Pinder, Mark A; Myrie, Semone B

    2017-01-01

    Creatine, a very popular supplement among athletic populations, is of growing interest for clinical applications. Since over 90% of creatine is stored in skeletal muscle, the effect of creatine supplementation on muscle metabolism is a widely studied area. While numerous studies over the past few decades have shown that creatine supplementation has many favorable effects on skeletal muscle physiology and metabolism, including enhancing muscle mass (growth/hypertrophy); the underlying mechanisms are poorly understood. This report reviews studies addressing the mechanisms of action of creatine supplementation on skeletal muscle growth/hypertrophy. Early research proposed that the osmotic effect of creatine supplementation serves as a cellular stressor (osmosensing) that acts as an anabolic stimulus for protein synthesis signal pathways. Other reports indicated that creatine directly affects muscle protein synthesis via modulations of components in the mammalian target of rapamycin (mTOR) pathway. Creatine may also directly affect the myogenic process (formation of muscle tissue), by altering secretions of myokines, such as myostatin and insulin-like growth factor-1, and expressions of myogenic regulatory factors, resulting in enhanced satellite cells mitotic activities and differentiation into myofiber. Overall, there is still no clear understanding of the mechanisms of action regarding how creatine affects muscle mass/growth, but current evidence suggests it may exert its effects through multiple approaches, with converging impacts on protein synthesis and myogenesis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats.

    PubMed

    Shankaran, Mahalakshmi; Shearer, Todd W; Stimpson, Stephen A; Turner, Scott M; King, Chelsea; Wong, Po-Yin Anne; Shen, Ying; Turnbull, Philip S; Kramer, Fritz; Clifton, Lisa; Russell, Alan; Hellerstein, Marc K; Evans, William J

    2016-03-15

    Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167-201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated (r(2) = 0.90-0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM. Copyright © 2016 the American Physiological Society.

  19. Lower extremity muscle size and strength and aerobic capacity decrease with caloric restriction but not with exercise-induced weight loss

    PubMed Central

    Weiss, Edward P.; Racette, Susan B.; Villareal, Dennis T.; Fontana, Luigi; Steger-May, Karen; Schechtman, Kenneth B.; Klein, Samuel; Ehsani, Ali A.; Holloszy, John O.

    2015-01-01

    Caloric restriction (CR) results in fat loss; however, it may also result in loss of muscle and thereby reduce strength and aerobic capacity (V̇O2 max). These effects may not occur with exercise-induced weight loss (EX) because of the anabolic effects of exercise on heart and skeletal muscle. We tested the hypothesis that CR reduces muscle size and strength and V̇O2 max, whereas EX preserves or improves these parameters. Healthy 50- to 60-yr-old men and women (body mass index of 23.5–29.9 kg/m2) were studied before and after 12 mo of weight loss by CR (n = 18) or EX (n = 16). Lean mass was assessed by dual-energy X-ray absorptiometry, thigh muscle volume by MRI, isometric and isokinetic knee flexor strength by dynamometry, and treadmill V̇O2 max by indirect calorimetry. Both interventions caused significant decreases in body weight (CR: −10.7 ± 1.4%, EX: −9.5 ± 1.5%) and lean mass (CR: −3.5 ± 0.7%, EX: −2.2 ± 0.8%), with no significant differences between groups. Significant decreases in thigh muscle volume (−6.9 ± 0.8%) and composite knee flexion strength (−7.2 ± 3%) occurred in the CR group only. Absolute V̇O2 max decreased significantly in the CR group (−6.8 ± 2.3%), whereas the EX group had significant increases in both absolute (+15.5 ± 2.4%) and relative (+28.3 ± 3.0%) V̇O2 max. These data provide evidence that muscle mass and absolute physical work capacity decrease in response to 12 mo of CR but not in response to a similar weight loss induced by exercise. These findings suggest that, during EX, the body adapts to maintain or even enhance physical performance capacity. PMID:17095635

  20. Myostatin inhibition in muscle, but not adipose tissue, decreases fat mass and improves insulin sensitivity.

    PubMed

    Guo, Tingqing; Jou, William; Chanturiya, Tatyana; Portas, Jennifer; Gavrilova, Oksana; McPherron, Alexandra C

    2009-01-01

    Myostatin (Mstn) is a secreted growth factor expressed in skeletal muscle and adipose tissue that negatively regulates skeletal muscle mass. Mstn(-/-) mice have a dramatic increase in muscle mass, reduction in fat mass, and resistance to diet-induced and genetic obesity. To determine how Mstn deletion causes reduced adiposity and resistance to obesity, we analyzed substrate utilization and insulin sensitivity in Mstn(-/-) mice fed a standard chow. Despite reduced lipid oxidation in skeletal muscle, Mstn(-/-) mice had no change in the rate of whole body lipid oxidation. In contrast, Mstn(-/-) mice had increased glucose utilization and insulin sensitivity as measured by indirect calorimetry, glucose and insulin tolerance tests, and hyperinsulinemic-euglycemic clamp. To determine whether these metabolic effects were due primarily to the loss of myostatin signaling in muscle or adipose tissue, we compared two transgenic mouse lines carrying a dominant negative activin IIB receptor expressed specifically in adipocytes or skeletal muscle. We found that inhibition of myostatin signaling in adipose tissue had no effect on body composition, weight gain, or glucose and insulin tolerance in mice fed a standard diet or a high-fat diet. In contrast, inhibition of myostatin signaling in skeletal muscle, like Mstn deletion, resulted in increased lean mass, decreased fat mass, improved glucose metabolism on standard and high-fat diets, and resistance to diet-induced obesity. Our results demonstrate that Mstn(-/-) mice have an increase in insulin sensitivity and glucose uptake, and that the reduction in adipose tissue mass in Mstn(-/-) mice is an indirect result of metabolic changes in skeletal muscle. These data suggest that increasing muscle mass by administration of myostatin antagonists may be a promising therapeutic target for treating patients with obesity or diabetes.

  1. Prevalence of skeletal muscle mass loss and its association with swallowing function after cardiovascular surgery.

    PubMed

    Wakabayashi, Hidetaka; Takahashi, Rimiko; Watanabe, Naoko; Oritsu, Hideyuki; Shimizu, Yoshitaka

    2017-06-01

    The aim of this study was to assess the prevalence of skeletal muscle mass loss and its association with swallowing function in patients with dysphagia after cardiovascular surgery. A retrospective cohort study was performed in 65 consecutive patients with dysphagia after cardiovascular surgery who were prescribed speech therapy. Skeletal muscle index (SMI) was calculated as total psoas muscle area assessed via abdominal computed tomography divided by height squared. Cutoff values were 6.36 cm 2 /m 2 for men and 3.92 cm 2 /m 2 for women. The Food Intake Level Scale (FILS) was used to assess the swallowing function. Univariate and ordered logistic regression analyses were applied to examine the associations between skeletal muscle mass loss and dysphagia. The study included 50 men and 15 women (mean age 73 ± 8 y). The mean SMI was 4.72 ± 1.37 cm 2 /m 2 in men and 3.33 ± 1.42 cm 2 /m 2 in women. Skeletal muscle mass loss was found in 53 (82%) patients. Twelve had tracheostomy cannula. Thirteen were non-oral feeding (FILS levels 1-3), 5 were oral food intake and alternative nutrition (levels 4-6), and 47 were oral food intake alone (levels 7-9) at discharge. The FILS at discharge was significantly lower in patients with skeletal muscle mass loss. Ordered logistic regression analysis of swallowing function showed that skeletal muscle mass loss and tracheostomy cannula were associated independently with the FILS at discharge. The prevalence of skeletal muscle mass loss is very high, and skeletal muscle mass loss is associated with swallowing function. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. A higher alkaline dietary load is associated with greater indexes of skeletal muscle mass in women.

    PubMed

    Welch, A A; MacGregor, A J; Skinner, J; Spector, T D; Moayyeri, A; Cassidy, A

    2013-06-01

    Conservation of muscle mass is important for fall and fracture prevention but further understanding of the causes of age-related muscle loss is required. This study found a more alkaline diet was positively associated with muscle mass in women suggesting a role for dietary acid-base load in muscle loss. Conservation of skeletal muscle is important for preventing falls and fractures but age-related loss of muscle mass occurs even in healthy individuals. However, the mild metabolic acidosis associated with an acidogenic dietary acid-base load could influence loss of muscle mass. We investigated the association between fat-free mass (FFM), percentage FFM (FFM%) and fat-free mass index (FFMI, weight/height²), measured using dual-energy X-ray absorptiometry in 2,689 women aged 18-79 years from the TwinsUK Study, and dietary acid-base load. Body composition was calculated according to quartile of potential renal acid load and adjusted for age, physical activity, misreporting and smoking habit (FFM, FFMI also for fat mass) and additionally with percentage protein. Fat-free mass was positively associated with a more alkalinogenic dietary load (comparing quartile 1 vs 4: FFM 0.79 kg P < 0.001, FFM% 1.06 % <0.001, FFMI 0.24 kg/m² P = 0.002), and with the ratio of fruits and vegetables to potential acidogenic foods. We observed a small but significant positive association between a more alkaline diet and muscle mass indexes in healthy women that was independent of age, physical activity and protein intake equating to a scale of effect between a fifth and one half of the observed relationship with 10 years of age. Although protein is important for maintenance of muscle mass, eating fruits and vegetables that supply adequate amounts of potassium and magnesium are also relevant. The results suggest a potential role for diet in the prevention of muscle loss.

  3. Weight reduction does not induce an undesirable decrease in muscle mass, muscle strength, or physical performance in men with obesity: a pilot study.

    PubMed

    Kim, Bokun; Tsujimoto, Takehiko; So, Rina; Zhao, Xiaoguang; Oh, Sechang; Tanaka, Kiyoji

    2017-12-31

    To date, there have been no reports on whether weight reduction causes decreases in muscle mass, muscle strength, or physical performance that could lead to health problems. Thus, in this pilot study, we investigated the appropriateness of the changes in muscle mass, muscle strength and physical performance after weight reduction. Obese men who completed a weight reduction program to decrease and maintain a body mass index (BMI) of less than 25 kg/m2 for one year were recruited for the study. One year after the completion of a weight reduction program, the participants' muscle mass, muscle strength, and physical performance were compared with those in a reference group composed of individuals whose BMI was less than 25 kg/m2. Whole-body scanning was performed using dual-energy X-ray absorptiometry to analyze muscle mass. Handgrip strength and knee extensor strength were measured to evaluate arm and leg muscle strength, respectively. For physical performance, a jump test was employed. The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<0.001). Weight reduction participants showed an average reduction in body weight of -16.47%. Normalized arm muscle mass and handgrip strength were significantly greater in the weight reduction group than in the reference group; however, no significant differences were detected between the two groups with respect to the other variables. After one year, there were no significant differences between the two groups. ©2017 The Korean Society for Exercise

  4. Muscle mass as a target to reduce fatigue in patients with advanced cancer.

    PubMed

    Neefjes, Elisabeth C W; van den Hurk, Renske M; Blauwhoff-Buskermolen, Susanne; van der Vorst, Maurice J D L; Becker-Commissaris, Annemarie; de van der Schueren, Marian A E; Buffart, Laurien M; Verheul, Henk M W

    2017-08-01

    Cancer-related fatigue (CRF) reduces quality of life and the activity level of patients with cancer. Cancer related fatigue can be reduced by exercise interventions that may concurrently increase muscle mass. We hypothesized that low muscle mass is directly related to higher CRF. A total of 233 patients with advanced cancer starting palliative chemotherapy for lung, colorectal, breast, or prostate cancer were studied. The skeletal muscle index (SMI) was calculated as the patient's muscle mass on level L3 or T4 of a computed tomography scan, adjusted for height. Fatigue was assessed with the Functional Assessment of Chronic Illness Therapy-fatigue questionnaire (cut-off for fatigue <34). Multiple linear regression analyses were conducted to study the association between SMI and CRF adjusting for relevant confounders. In this group of patients with advanced cancer, the median fatigue score was 36 (interquartile range 26-44). A higher SMI on level L3 was significantly associated with less CRF for men (B 0.447, P 0.004) but not for women (B - 0.401, P 0.090). No association between SMI on level T4 and the Functional Assessment of Chronic Illness Therapy-fatigue score was found (n = 82). The association between SMI and CRF may lead to the suggestion that male patients may be able to reduce fatigue by exercise interventions aiming at an increased muscle mass. In women with advanced cancer, CRF is more influenced by other causes, because it is not significantly related to muscle mass. To further reduce CRF in both men and women with cancer, multifactorial assessments need to be performed in order to develop effective treatment strategies. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  5. Determination of muscle mass changes in legs from K-40 measurements

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.; Rieksts, G. A.

    1979-01-01

    The K-40 content of the upper legs was periodically measured in several subjects whose injured legs had been in a cast for 6 weeks or more. As the subjects began using the leg again, the K-40 content increased as the muscle tissue was replaced. A 25% increase in K-40 content in 6 months is typical for a normal leg use and recovery. This is equivalent to an original muscle mass loss of 20%. By measuring specific body regions, such as arms or legs, with a high-efficiency detector system, muscle mass changes which exceed a few percent can be measured. These methods could be used in space flight and bedrest studies, and in studying nutritional deficiencies due to disease or diet.

  6. Glucocorticoid sensitivity, disuse, and the regulation of muscle mass

    NASA Technical Reports Server (NTRS)

    Almon, R. R.; Dubois, D. C.

    1983-01-01

    A new noninvasive immobilization procedure to be used on rats has been developed to study immobilization-induced muscle hypersensitivity to normal glucocorticoid concentration, subsequent muscle atrophy, and atrophy recovery. The immobilization procedure involves encasing the hind limb in a light-weight plasticlike cast (10 percent the usual plaster weight), completely resistant to animal gnawing. The effects of right-angle immobilization of the ankle on the slow fiber soleus, and the fast fiber extensor digitorum longus, resemble the effects of weightlessness. The increased concentration of glucocorticoid receptor sites in immobilized and denervated muscle is discussed, along with the chronic loss of muscle mass that occurs in practically all dystrophies. It is concluded that lack of mechanical work in a zero gravity environment is a major cause of glucocorticoid hypersensitivity in the body's musculature.

  7. A myostatin inhibitor (propeptide-Fc) increases muscle mass and muscle fiber size in aged mice but does not increase bone density or bone strength.

    PubMed

    Arounleut, Phonepasong; Bialek, Peter; Liang, Li-Fang; Upadhyay, Sunil; Fulzele, Sadanand; Johnson, Maribeth; Elsalanty, Mohammed; Isales, Carlos M; Hamrick, Mark W

    2013-09-01

    Loss of muscle and bone mass with age are significant contributors to falls and fractures among the elderly. Myostatin deficiency is associated with increased muscle mass in mice, dogs, cows, sheep and humans, and mice lacking myostatin have been observed to show increased bone density in the limb, spine, and jaw. Transgenic overexpression of myostatin propeptide, which binds to and inhibits the active myostatin ligand, also increases muscle mass and bone density in mice. We therefore sought to test the hypothesis that in vivo inhibition of myostatin using an injectable myostatin propeptide (GDF8 propeptide-Fc) would increase both muscle mass and bone density in aged (24 mo) mice. Male mice were injected weekly (20 mg/kg body weight) with recombinant myostatin propeptide-Fc (PRO) or vehicle (VEH; saline) for four weeks. There was no difference in body weight between the two groups at the end of the treatment period, but PRO treatment significantly increased mass of the tibialis anterior muscle (+ 7%) and increased muscle fiber diameter of the extensor digitorum longus (+ 16%) and soleus (+ 6%) muscles compared to VEH treatment. Bone volume relative to total volume (BV/TV) of the femur calculated by microCT did not differ significantly between PRO- and VEH-treated mice, and ultimate force (Fu), stiffness (S), toughness (U) measured from three-point bending tests also did not differ significantly between groups. Histomorphometric assays also revealed no differences in bone formation or resorption in response to PRO treatment. These data suggest that while developmental perturbation of myostatin signaling through either gene knockout or transgenic inhibition may alter both muscle and bone mass in mice, pharmacological inhibition of myostatin in aged mice has a more pronounced effect on skeletal muscle than on bone. © 2013. Published by Elsevier Inc. All rights reserved.

  8. Muscle mass, structural and functional investigations of senescence-accelerated mouse P8 (SAMP8)

    PubMed Central

    Guo, An Yun; Leung, Kwok Sui; Siu, Parco Ming Fai; Qin, Jiang Hui; Chow, Simon Kwoon Ho; Qin, Ling; Li, Chi Yu; Cheung, Wing Hoi

    2015-01-01

    Sarcopenia is an age-related systemic syndrome with progressive deterioration in skeletal muscle functions and loss in mass. Although the senescence-accelerated mouse P8 (SAMP8) was reported valid for muscular ageing research, there was no report on the details such as sarcopenia onset time. Therefore, this study was to investigate the change of muscle mass, structure and functions during the development of sarcopenia. Besides the average life span, muscle mass, structural and functional measurements were also studied. Male SAMP8 animals were examined at month 6, 7, 8, 9, and 10, in which the right gastrocnemius was isolated and tested for ex vivo contractile properties and fatigability while the contralateral one was harvested for muscle fiber cross-sectional area (FCSA) and typing assessments. Results showed that the peak of muscle mass appeared at month 7 and the onset of contractility decline was observed from month 8. Compared with month 8, most of the functional parameters at month 10 decreased significantly. Structurally, muscle fiber type IIA made up the largest proportion of the gastrocnemius, and the fiber size was found to peak at month 8. Based on the altered muscle mass, structural and functional outcomes, it was concluded that the onset of sarcopenia in SAMP8 animals was at month 8. SAMP8 animals at month 8 should be at pre-sarcopenia stage while month 10 at sarcopenia stage. It is confirmed that SAMP8 mouse can be used in sarcopenia research with established time line in this study. PMID:26193895

  9. Ultrasonography to Measure Swallowing Muscle Mass and Quality in Older Patients With Sarcopenic Dysphagia.

    PubMed

    Ogawa, Nami; Mori, Takashi; Fujishima, Ichiro; Wakabayashi, Hidetaka; Itoda, Masataka; Kunieda, Kenjiro; Shigematsu, Takashi; Nishioka, Shinta; Tohara, Haruka; Yamada, Minoru; Ogawa, Sumito

    2018-06-01

    Sarcopenic dysphagia is characterized by difficulty swallowing due to a loss of whole-body skeletal and swallowing muscle mass and function. However, no study has reported on swallowing muscle mass and quality in patients with sarcopenic dysphagia. To compare the differences in swallowing muscle mass and quality between sarcopenic and nonsarcopenic dysphagia. A cross-sectional study was performed in 55 older patients, who had been recommended to undergo dysphagia assessment and/or rehabilitation. Sarcopenic dysphagia was diagnosed using a diagnostic algorithm for sarcopenic dysphagia. The thickness and area of tongue muscle and geniohyoid muscle (coronal plane and sagittal plane), and the echo-intensity of the tongue and geniohyoid muscles were examined by ultrasound. The study participants included 31 males and 24 females (mean age of 82 ± 7 years), with 14 having possible sarcopenic dysphagia, 22 probable sarcopenic dysphagia, and 19 without sarcopenic dysphagia. The group with sarcopenic dysphagia had a significantly lower cross-sectional area and area of brightness of the tongue muscle than that observed in the group without sarcopenic dysphagia. The most specific factor for identifying the presence of sarcopenic dysphagia was tongue muscle area (sensitivity, 0.389; specificity, 0.947; cut-off value, 1536.0), while the factor with the highest sensitivity was geniohyoid muscle area brightness in sagittal sections (sensitivity, 0.806; specificity, 0.632; cut-off value, 20.1). Multivariate logistic regression analysis showed that the area of the tongue muscle and its area of brightness were independent risk factors for sarcopenic dysphagia. However, geniohyoid sagittal muscle area and area of brightness showed no significant independent association with sarcopenic dysphagia. Tongue muscle mass in patients with sarcopenic dysphagia was smaller than that in patients without the condition. Sarcopenic dysphagia was also associated with increased intensity of the

  10. Dairy food intake, peripheral bone structure, and muscle mass in elderly ambulatory women.

    PubMed

    Radavelli-Bagatini, Simone; Zhu, Kun; Lewis, Joshua R; Prince, Richard L

    2014-07-01

    Previous studies suggest that dairy intake may be associated with reduced bone and muscle loss with aging, but there are limited data in the very old. We evaluated the association between intake of dairy foods and peripheral bone structure and muscle mass in 564 elderly women aged 80 to 92 (mean 84.7) years, who were participants of the Calcium Intake Fracture Outcome Study/CAIFOS Aged Extension Study (CAIFOS/CARES) cohort and attended the 10-year follow-up. Assessments included dairy consumption (milk, yogurt, and cheese) by a validated food frequency questionnaire, 15% tibia bone mass, area and volumetric bone mineral density (vBMD) by peripheral quantitative computed tomography (pQCT), and appendicular bone and skeletal muscle mass by dual-energy X-ray absorptiometry (DXA). Women were categorized according to tertiles of dairy intake: first tertile (≤ 1.5 servings/d), second tertile (1.5 to 2.2 servings/d) and third tertile (≥ 2.2 servings/d). Controlling for confounding factors, pQCT assessment at the 15% tibia showed that compared with those in the first tertile of dairy intake, women in the third tertile had 5.7% greater total bone mass (p = 0.005), principally because of an increase in cortical and subcortical bone mass (5.9%, p = 0.050), resulting in a 6.2% increase in total vBMD (p = 0.013). Trabecular but not cortical and subcortical vBMD was also higher (7.8%, p = 0.044). DXA assessment showed that women in the third tertile of dairy intake had greater appendicular bone mass (7.1%, p = 0.007) and skeletal muscle mass (3.3%, p = 0.014) compared with tertile 1. The associations with bone measures were dependent on dairy protein and calcium intakes, whereas the association with appendicular muscle mass was not totally dependent on dairy protein intake. Our results suggest a positive association of dairy intake with appendicular bone mineralization and muscle mass in elderly women. Because many fractures in this age group are of the appendicular skeleton

  11. The AMPK-related kinase SNARK regulates muscle mass and myocyte survival

    USDA-ARS?s Scientific Manuscript database

    The maintenance of skeletal muscle mass is critical for sustaining health; however, the mechanisms responsible for muscle loss with aging and chronic diseases, such as diabetes and obesity, are poorly understood. We found that expression of a member of the AMPK-related kinase family, the SNF1-AMPK-r...

  12. Psoas Muscle Cross-sectional Area as a Measure of Whole-body Lean Muscle Mass in Maintenance Hemodialysis Patients.

    PubMed

    Morrell, Glen R; Ikizler, Talat A; Chen, Xiaorui; Heilbrun, Marta E; Wei, Guo; Boucher, Robert; Beddhu, Srinivasan

    2016-07-01

    We investigate whether psoas or paraspinous muscle area measured on a single L4-L5 image is a useful measure of whole lean body mass (LBM) compared to dedicated midthigh magnetic resonance imaging (MRI). Observational study. Outpatient dialysis units and a research clinic. One hundred five adult participants on maintenance hemodialysis. No control group was used. Psoas muscle area, paraspinous muscle area, and midthigh muscle area (MTMA) were measured by magnetic resonance imaging. LBM was measured by dual-energy absorptiometry scan. In separate multivariable linear regression models, psoas, paraspinous, and MTMA were associated with increase in LBM. In separate multivariate logistic regression models, C statistics for diagnosis of sarcopenia (defined as <25th percentile of LBM) were 0.69 for paraspinous muscle area, 0.81 for psoas muscle area, and 0.89 for MTMA. With sarcopenia defined as <10th percentile of LBM, the corresponding C statistics were 0.71, 0.92, and 0.94. We conclude that psoas muscle area provides a good measure of whole-body muscle mass, better than paraspinous muscle area but slightly inferior to midthigh measurement. Hence, in body composition studies a single axial MR image at the L4-L5 level can be used to provide information on both fat and muscle and may eliminate the need for time-consuming measurement of muscle area in the thigh. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  13. Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease: A review of the English-language literature.

    PubMed

    De Brandt, Jana; Spruit, Martijn A; Hansen, Dominique; Franssen, Frits Me; Derave, Wim; Sillen, Maurice Jh; Burtin, Chris

    2018-05-01

    Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcome measures. This review uses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies ( n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, and water-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients.

  14. Changes in lower limb muscle function and muscle mass following exercise-based interventions in patients with chronic obstructive pulmonary disease: A review of the English-language literature

    PubMed Central

    De Brandt, Jana; Spruit, Martijn A; Hansen, Dominique; Franssen, Frits ME; Derave, Wim; Sillen, Maurice JH; Burtin, Chris

    2017-01-01

    Chronic obstructive pulmonary disease (COPD) patients often experience lower limb muscle dysfunction and wasting. Exercise-based training has potential to improve muscle function and mass, but literature on this topic is extensive and heterogeneous including numerous interventions and outcome measures. This review uses a detailed systematic approach to investigate the effect of this wide range of exercise-based interventions on muscle function and mass. PUBMED and PEDro databases were searched. In all, 70 studies (n = 2504 COPD patients) that implemented an exercise-based intervention and reported muscle strength, endurance, or mass in clinically stable COPD patients were critically appraised. Aerobic and/or resistance training, high-intensity interval training, electrical or magnetic muscle stimulation, whole-body vibration, and water-based training were investigated. Muscle strength increased in 78%, muscle endurance in 92%, and muscle mass in 88% of the cases where that specific outcome was measured. Despite large heterogeneity in exercise-based interventions and outcome measures used, most exercise-based trials showed improvements in muscle strength, endurance, and mass in COPD patients. Which intervention(s) is (are) best for which subgroup of patients remains currently unknown. Furthermore, this literature review identifies gaps in the current knowledge and generates recommendations for future research to enhance our knowledge on exercise-based interventions in COPD patients. PMID:28580854

  15. Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass

    PubMed Central

    Rader, Erik P; Miller, G Roger; Chetlin, Robert D; Wirth, Oliver; Baker, Brent A

    2014-01-01

    Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training – when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load) on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL) and tibialis anterior (TA) muscles, 700 g load training increased muscle fiber number per unit area by ∼20% and decreased muscle fiber area by ∼20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training. PMID:25392697

  16. Low Mass Muscle Actuators (LoMMAs) Using Electroactive Polymers

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.; Xue, T.; Joffe, B.; Lih, S. S.; Willis, P.; Simpson, J.; Smith, J.; Clair, T.; Shahinpoor, M.

    1997-01-01

    NASA is using actuation devices for many space applications and there is an increasing need to cut their cost as well as reduce their size, mass, and power consumption. Existing transducing actuators, such as piezoceramics, are inducing limited displacement levels. Potentially, electroactive polymers (so called EAP) can be formed as inexpensive, low-mass, low-power, miniature muscle actuators that are superior to the widely used actuators.

  17. Muscle Mass and Weight Gain Nutritional Supplements

    NASA Astrophysics Data System (ADS)

    Campbell, Bill

    There are numerous sports supplements available that claim to increase lean body mass. However, for these sports supplements to exert any favorable changes in lean body mass, they must influence those factors regulating skeletal muscle hypertrophy (i.e., satellite cell activity, gene transcription, protein translation). If a given sports supplement does favorably influence one of these regulatory factors, the result is a positive net protein balance (in which protein synthesis exceeds protein breakdown). Sports supplement categories aimed at eliciting a positive net protein balance include anabolic hormone enhancers, nutrient timing pre- and postexercise workout supplements, anticatabolic supplements, and nitric oxide boosters. Of all the sports supplements available, only a few have been subject to multiple clinical trials with repeated favorable outcomes relative to increasing lean body mass. This chapter focuses on these supplements and others that have a sound theoretical rationale in relation to increasing lean body mass.

  18. Texture-modified diets are associated with decreased muscle mass in older adults admitted to a rehabilitation ward.

    PubMed

    Shimizu, Akio; Maeda, Keisuke; Tanaka, Kei; Ogawa, Mei; Kayashita, Jun

    2018-05-01

    Texture-modified diets (TMD) have significantly lower energy and protein content than normal diets. Therefore, TMD can cause malnutrition and loss of muscle mass. However, few studies have reported the relationship between TMD and decreased skeletal muscle mass. The aim of the present study was to clarify the association between TMD and decreased skeletal muscle mass. We reviewed data of 188 older adult patients who were admitted to a rehabilitation hospital. TMD were defined based on the Japanese Dysphagia Diet Criteria 2013 proposed by the Japanese Society of Dysphagia Rehabilitation. The Mini Nutritional Assessment-Short Form was used to assess nutritional status; dual-energy X-ray absorptiometry was used to measure the skeletal muscle mass index, and the cut-off values for decreased skeletal muscle mass index were based on the Asian Working Group for Sarcopenia; the Functional Independence Measure was used to evaluate activities of daily living. The patients' mean age was 80.6 ± 7.5 years, and 62% were women. A total of 22 patients (11.7%) consumed TMD. A total of 104 patients (55.3%) had decreased skeletal muscle mass, and approximately 90% of them consumed TMD. Decreased skeletal muscle mass index (odds ratio 7.199, 95% confidence interval 1.489-34.805, P ≤ 0.01) and Functional Independence Measure scores (odds ratio 0.972, 95% confidence interval 0.952-0.992, P ≤ 0.01) were independently related to TMD in the multivariate analysis. The TMD group was associated with decreased skeletal muscle mass. Future, prospective studies are necessary to investigate causality. Geriatr Gerontol Int 2018; 18: 698-704. © 2017 Japan Geriatrics Society.

  19. Calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry assays and its application in supporting microdose absolute bioavailability studies.

    PubMed

    Gu, Huidong; Wang, Jian; Aubry, Anne-Françoise; Jiang, Hao; Zeng, Jianing; Easter, John; Wang, Jun-sheng; Dockens, Randy; Bifano, Marc; Burrell, Richard; Arnold, Mark E

    2012-06-05

    A methodology for the accurate calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) assays and its application in supporting microdose absolute bioavailability studies are reported for the first time. For simplicity, this calculation methodology and the strategy to minimize the isotopic interference are demonstrated using a simple molecule entity, then applied to actual development drugs. The exact isotopic interferences calculated with this methodology were often much less than the traditionally used, overestimated isotopic interferences simply based on the molecular isotope abundance. One application of the methodology is the selection of a stable isotopically labeled internal standard (SIL-IS) for an LC-MS/MS bioanalytical assay. The second application is the selection of an SIL analogue for use in intravenous (i.v.) microdosing for the determination of absolute bioavailability. In the case of microdosing, the traditional approach of calculating isotopic interferences can result in selecting a labeling scheme that overlabels the i.v.-dosed drug or leads to incorrect conclusions on the feasibility of using an SIL drug and analysis by LC-MS/MS. The methodology presented here can guide the synthesis by accurately calculating the isotopic interferences when labeling at different positions, using different selective reaction monitoring (SRM) transitions or adding more labeling positions. This methodology has been successfully applied to the selection of the labeled i.v.-dosed drugs for use in two microdose absolute bioavailability studies, before initiating the chemical synthesis. With this methodology, significant time and cost saving can be achieved in supporting microdose absolute bioavailability studies with stable labeled drugs.

  20. Combination of body mass-based resistance training and high-intensity walking can improve both muscle size and V˙O2 peak in untrained older women.

    PubMed

    Ozaki, Hayao; Kitada, Tomoharu; Nakagata, Takashi; Naito, Hisashi

    2017-05-01

    Here, we aimed to compare the effect of a combination of body mass-based resistance exercise and moderate-intensity (55% peak oxygen uptake [ V˙O 2 peak]) walking or high-intensity (75% V˙O 2 peak) walking on muscle size and V˙O 2 peak in untrained older women. A total of 12 untrained older women (mean age 60 ± 2 years) were randomly assigned to either a moderate-intensity aerobic training group (n = 6) or high-intensity aerobic training group (n = 6). Both groups carried out body-mass based (lower body) resistance exercises (2 sets of 10 repetitions) on 3 days/week for 8 weeks. Between these exercises, the participants in the moderate-intensity aerobic training group walked at a previously determined speed equivalent to 55% V˙O 2 peak, whereas those in the high-intensity aerobic training group walked at a speed equivalent to 75% V˙O 2 peak. Muscle thickness of the anterior aspect of the thigh and maximal isokinetic knee extension strength significantly increased in both groups (P < 0.01); these relative changes were negatively correlated with the absolute muscle thickness of the anterior aspect of the thigh value and the relative value of maximal knee strength to body mass at pre-intervention, respectively. A significant group × time interaction was noted for V˙O 2 peak (P < 0.05), which increased only in the high-intensity aerobic training group. Body mass-based resistance training significantly induced muscle hypertrophy in untrained older women. In particular, lower muscle thickness before intervention was associated with greater training-induced growth. Furthermore, V˙O 2 peak can be increased by combined circuit training involving low-load resistance exercise and walking, particularly when a relatively high intensity of walking is maintained. Geriatr Gerontol Int 2017; 17: 779-784. © 2016 Japan Geriatrics Society.

  1. Impact of hypercortisolism on skeletal muscle mass and adipose tissue mass in patients with adrenal adenomas.

    PubMed

    Delivanis, Danae A; Iñiguez-Ariza, Nicole M; Zeb, Muhammad H; Moynagh, Michael R; Takahashi, Naoki; McKenzie, Travis J; Thomas, Melinda A; Gogos, Charalambos; Young, William F; Bancos, Irina; Kyriazopoulou, Venetsana

    2018-02-01

    Abdominal visceral adiposity and central sarcopenia are markers of increased cardiovascular risk and mortality. To assess whether central sarcopenia and adiposity can serve as a marker of disease severity in patients with adrenal adenomas and glucocorticoid secretory autonomy. Retrospective cohort study. Twenty-five patients with overt Cushing's syndrome (CS), 48 patients with mild autonomous cortisol excess (MACE) and 32 patients with a nonfunctioning adrenal tumour (NFAT) were included. Medical records were reviewed, and body composition measurements (visceral fat [VAT], subcutaneous fat [SAT], visceral/total fat [V/T], visceral/subcutaneous [V/S] and total abdominal muscle mass) were calculated based on abdominal computed tomography (CT). In patients with overt CS, when compared to patients with NFAT, the V/T fat and the V/S ratio were increased by 0.08 (P < .001) and by 0.3 (P < .001); however, these measurements were decreased by 0.04 (P = .007) and 0.2 (P = .01), respectively, in patients with MACE. Total muscle mass was decreased by -10 cm 2 (P = .02) in patients with overt CS compared to patients with NFAT. Correlation with morning serum cortisol concentrations after dexamethasone suppression testing revealed that for every 28 nmol/L cortisol increase there was a 0.008 increase in V/T (P < .001), 0.02 increase in the V/S fat ratio (P < .001) and a 1.2 cm 2 decrease in mean total muscle mass (P = .002). The severity of hypercortisolism was correlated with lower muscle mass and higher visceral adiposity. These CT-based markers may allow for a more reliable and objective assessment of glucocorticoid-related disease severity in patients with adrenal adenomas. © 2017 John Wiley & Sons Ltd.

  2. Muscle mass decline, arterial stiffness, white matter hyperintensity, and cognitive impairment: Japan Shimanami Health Promoting Program study.

    PubMed

    Kohara, Katsuhiko; Okada, Yoko; Ochi, Masayuki; Ohara, Maya; Nagai, Tokihisa; Tabara, Yasuharu; Igase, Michiya

    2017-08-01

    There is a close association between frailty and cognitive impairment. However, the underlying contribution of sarcopenia to the development of cognitive impairment is unclear. We investigated the possible association between muscle mass decline and cognitive impairment in a cross-sectional study of 1518 subjects aged 55 years or above. We also evaluated arterial stiffness and white matter hyperintensities (WMHs) as possible underlying mechanisms for this association. Two sarcopenic indices were measured: thigh muscle cross-sectional area (CSA; calculated by computed tomography) and skeletal muscle mass (bioelectric impedance). Muscle mass decline was defined as either the bottom 10% or 20% of participants for each sex. Cognitive function was assessed using the Touch Panel-type Dementia Assessment Scale, and brachial-ankle pulse wave velocity was measured as an index of arterial stiffness. Both sarcopenic indices were modestly but significantly associated with brachial-ankle pulse wave velocity in male and female subjects. The presence of WMHs was significantly associated with low thigh muscle CSA in men and with low skeletal muscle mass in women. The Touch Panel-type Dementia Assessment Scale score was modestly but significantly and positively associated with thigh muscle CSA in men and skeletal muscle mass in women. Muscle mass decline in the bottom 10% of participants on both sarcopenic indices was significantly and independently related to cognitive impairment in women. Lower sarcopenic indices are significantly related to lower cognitive scores. Arterial stiffness and WMHs could account, at least in part, for this association. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  3. Muscle mass decline, arterial stiffness, white matter hyperintensity, and cognitive impairment: Japan Shimanami Health Promoting Program study

    PubMed Central

    Okada, Yoko; Ochi, Masayuki; Ohara, Maya; Nagai, Tokihisa; Tabara, Yasuharu; Igase, Michiya

    2017-01-01

    Abstract Background There is a close association between frailty and cognitive impairment. However, the underlying contribution of sarcopenia to the development of cognitive impairment is unclear. We investigated the possible association between muscle mass decline and cognitive impairment in a cross‐sectional study of 1518 subjects aged 55 years or above. We also evaluated arterial stiffness and white matter hyperintensities (WMHs) as possible underlying mechanisms for this association. Methods Two sarcopenic indices were measured: thigh muscle cross‐sectional area (CSA; calculated by computed tomography) and skeletal muscle mass (bioelectric impedance). Muscle mass decline was defined as either the bottom 10% or 20% of participants for each sex. Cognitive function was assessed using the Touch Panel‐type Dementia Assessment Scale, and brachial–ankle pulse wave velocity was measured as an index of arterial stiffness. Results Both sarcopenic indices were modestly but significantly associated with brachial–ankle pulse wave velocity in male and female subjects. The presence of WMHs was significantly associated with low thigh muscle CSA in men and with low skeletal muscle mass in women. The Touch Panel‐type Dementia Assessment Scale score was modestly but significantly and positively associated with thigh muscle CSA in men and skeletal muscle mass in women. Muscle mass decline in the bottom 10% of participants on both sarcopenic indices was significantly and independently related to cognitive impairment in women. Conclusions Lower sarcopenic indices are significantly related to lower cognitive scores. Arterial stiffness and WMHs could account, at least in part, for this association. PMID:28371474

  4. Effect of anabolic steroids on skeletal muscle mass during hindlimb suspension

    NASA Technical Reports Server (NTRS)

    Tsika, R. W.; Herrick, R. E.; Baldwin, K. M.

    1987-01-01

    The effect of treatment with an anabolic steroid (nandrolone decanoate) on the muscle mass of plantaris and soleus of a rats in hindlimb suspension, and on the isomyosin expression in these muscles, was investigated in young female rats divided into four groups: normal control (NC), normal steroid (NS), normal suspension (N-sus), and suspension steroid (sus-S). Steroid treatment of suspended animals (sus-S vs N-sus) was found to partially spare body weight and muscle weight, as well as myofibril content of plantaris (but not soleus), but did not modify the isomyosin pattern induced by suspension. In normal rats (NS vs NC), steroid treatment did enhance body weight and plantaris muscle weight; the treatment did not alter isomyosin expression in either muscle type.

  5. Pulmonary inflammation-induced loss and subsequent recovery of skeletal muscle mass require functional poly-ubiquitin conjugation.

    PubMed

    Ceelen, Judith J M; Schols, Annemie M W J; Thielen, Nathalie G M; Haegens, Astrid; Gray, Douglas A; Kelders, Marco C J M; de Theije, Chiel C; Langen, Ramon C J

    2018-05-02

    Pulmonary inflammation in response to respiratory infections can evoke muscle wasting. Increased activity of the ubiquitin (Ub)-proteasome system (UPS) and the autophagy lysosome pathway (ALP) have been implicated in inflammation-induced muscle atrophy. Since poly-Ub conjugation is required for UPS-mediated proteolysis and has been implicated in the ALP, we assessed the effect of impaired ubiquitin conjugation on muscle atrophy and recovery following pulmonary inflammation, and compared activation and suppression of these proteolytic systems to protein synthesis regulation. Pulmonary inflammation was induced in mice by an intratracheal instillation of LPS. Proteolysis (UPS and ALP) and synthesis signaling were examined in gastrocnemius muscle homogenates. Ub-conjugation-dependency of muscle atrophy and recovery was addressed using Ub-K48R (K48R) mice with attenuated poly-ubiquitin conjugation, and compared to UBWT control mice. Pulmonary inflammation caused a decrease in skeletal muscle mass which was accompanied by a rapid increase in expression of UPS and ALP constituents and reduction in protein synthesis signaling acutely after LPS. Muscle atrophy was attenuated in K48R mice, while ALP and protein synthesis signaling were not affected. Muscle mass recovery starting 72 h post LPS, correlated with reduced expression of UPS and ALP constituents and restoration of protein synthesis signaling. K48R mice however displayed impaired recovery of muscle mass. Pulmonary inflammation-induced muscle atrophy is in part attributable to UPS-mediated proteolysis, as activation of ALP- and suppression of protein synthesis signaling occur independently of poly-Ub conjugation during muscle atrophy. Recovery of muscle mass following pulmonary inflammation involves inverse regulation of proteolysis and protein synthesis signaling, and requires a functional poly-Ub conjugation.

  6. Absolute mass scale calibration in the inverse problem of the physical theory of fireballs.

    NASA Astrophysics Data System (ADS)

    Kalenichenko, V. V.

    A method of the absolute mass scale calibration is suggested for solving the inverse problem of the physical theory of fireballs. The method is based on the data on the masses of the fallen meteorites whose fireballs have been photographed in their flight. The method may be applied to those fireballs whose bodies have not experienced considerable fragmentation during their destruction in the atmosphere and have kept their form well enough. Statistical analysis of the inverse problem solution for a sufficiently representative sample makes it possible to separate a subsample of such fireballs. The data on the Lost City and Innisfree meteorites are used to obtain calibration coefficients.

  7. Androgen Action via the Androgen Receptor in Neurons Within the Brain Positively Regulates Muscle Mass in Male Mice.

    PubMed

    Davey, Rachel A; Clarke, Michele V; Russell, Patricia K; Rana, Kesha; Seto, Jane; Roeszler, Kelly N; How, Jackie M Y; Chia, Ling Yeong; North, Kathryn; Zajac, Jeffrey D

    2017-10-01

    Although it is well established that exogenous androgens have anabolic effects on skeletal muscle mass in humans and mice, data from muscle-specific androgen receptor (AR) knockout (ARKO) mice indicate that myocytic expression of the AR is dispensable for hind-limb muscle mass accrual in males. To identify possible indirect actions of androgens via the AR in neurons to regulate muscle, we generated neuron-ARKO mice in which the dominant DNA binding-dependent actions of the AR are deleted in neurons of the cortex, forebrain, hypothalamus, and olfactory bulb. Serum testosterone and luteinizing hormone levels were elevated twofold in neuron-ARKO males compared with wild-type littermates due to disruption of negative feedback to the hypothalamic-pituitary-gonadal axis. Despite this increase in serum testosterone levels, which was expected to increase muscle mass, the mass of the mixed-fiber gastrocnemius (Gast) and the fast-twitch fiber extensor digitorum longus hind-limb muscles was decreased by 10% in neuron-ARKOs at 12 weeks of age, whereas muscle strength and fatigue of the Gast were unaffected. The mass of the soleus muscle, however, which consists of a high proportion of slow-twitch fibers, was unaffected in neuron-ARKOs, demonstrating a stimulatory action of androgens via the AR in neurons to increase the mass of fast-twitch hind-limb muscles. Furthermore, neuron-ARKOs displayed reductions in voluntary and involuntary physical activity by up to 60%. These data provide evidence for a role of androgens via the AR in neurons to positively regulate fast-twitch hind-limb muscle mass and physical activity in male mice. Copyright © 2017 Endocrine Society.

  8. Low skeletal muscle mass is associated with increased hospital expenditure in patients undergoing cancer surgery of the alimentary tract.

    PubMed

    van Vugt, Jeroen L A; Buettner, Stefan; Levolger, Stef; Coebergh van den Braak, Robert R J; Suker, Mustafa; Gaspersz, Marcia P; de Bruin, Ron W F; Verhoef, Cornelis; van Eijck, Casper H C; Bossche, Niek; Groot Koerkamp, Bas; IJzermans, Jan N M

    2017-01-01

    Low skeletal muscle mass is associated with poor postoperative outcomes in cancer patients. Furthermore, it is associated with increased healthcare costs in the United States. We investigated its effect on hospital expenditure in a Western-European healthcare system, with universal access. Skeletal muscle mass (assessed on CT) and costs were obtained for patients who underwent curative-intent abdominal cancer surgery. Low skeletal muscle mass was defined based on pre-established cut-offs. The relationship between low skeletal muscle mass and hospital costs was assessed using linear regression analysis and Mann-Whitney U-tests. 452 patients were included (median age 65, 61.5% males). Patients underwent surgery for colorectal cancer (38.9%), colorectal liver metastases (27.4%), primary liver tumours (23.2%), and pancreatic/periampullary cancer (10.4%). In total, 45.6% had sarcopenia. Median costs were €2,183 higher in patients with low compared with patients with high skeletal muscle mass (€17,144 versus €14,961; P<0.001). Hospital costs incrementally increased with lower sex-specific skeletal muscle mass quartiles (P = 0.029). After adjustment for confounders, low skeletal muscle mass was associated with a cost increase of €4,061 (P = 0.015). Low skeletal muscle mass was independently associated with increased hospital costs of about €4,000 per patient. Strategies to reduce skeletal muscle wasting could reduce hospital costs in an era of incremental healthcare costs and an increasingly ageing population.

  9. Maternal and paternal genomes differentially affect myofibre characteristics and muscle weights of bovine fetuses at midgestation.

    PubMed

    Xiang, Ruidong; Ghanipoor-Samami, Mani; Johns, William H; Eindorf, Tanja; Rutley, David L; Kruk, Zbigniew A; Fitzsimmons, Carolyn J; Thomsen, Dana A; Roberts, Claire T; Burns, Brian M; Anderson, Gail I; Greenwood, Paul L; Hiendleder, Stefan

    2013-01-01

    Postnatal myofibre characteristics and muscle mass are largely determined during fetal development and may be significantly affected by epigenetic parent-of-origin effects. However, data on such effects in prenatal muscle development that could help understand unexplained variation in postnatal muscle traits are lacking. In a bovine model we studied effects of distinct maternal and paternal genomes, fetal sex, and non-genetic maternal effects on fetal myofibre characteristics and muscle mass. Data from 73 fetuses (Day153, 54% term) of four genetic groups with purebred and reciprocal cross Angus and Brahman genetics were analyzed using general linear models. Parental genomes explained the greatest proportion of variation in myofibre size of Musculus semitendinosus (80-96%) and in absolute and relative weights of M. supraspinatus, M. longissimus dorsi, M. quadriceps femoris and M. semimembranosus (82-89% and 56-93%, respectively). Paternal genome in interaction with maternal genome (P<0.05) explained most genetic variation in cross sectional area (CSA) of fast myotubes (68%), while maternal genome alone explained most genetic variation in CSA of fast myofibres (93%, P<0.01). Furthermore, maternal genome independently (M. semimembranosus, 88%, P<0.0001) or in combination (M. supraspinatus, 82%; M. longissimus dorsi, 93%; M. quadriceps femoris, 86%) with nested maternal weight effect (5-6%, P<0.05), was the predominant source of variation for absolute muscle weights. Effects of paternal genome on muscle mass decreased from thoracic to pelvic limb and accounted for all (M. supraspinatus, 97%, P<0.0001) or most (M. longissimus dorsi, 69%, P<0.0001; M. quadriceps femoris, 54%, P<0.001) genetic variation in relative weights. An interaction between maternal and paternal genomes (P<0.01) and effects of maternal weight (P<0.05) on expression of H19, a master regulator of an imprinted gene network, and negative correlations between H19 expression and fetal muscle mass (P<0

  10. Maternal and Paternal Genomes Differentially Affect Myofibre Characteristics and Muscle Weights of Bovine Fetuses at Midgestation

    PubMed Central

    Xiang, Ruidong; Ghanipoor-Samami, Mani; Johns, William H.; Eindorf, Tanja; Rutley, David L.; Kruk, Zbigniew A.; Fitzsimmons, Carolyn J.; Thomsen, Dana A.; Roberts, Claire T.; Burns, Brian M.; Anderson, Gail I.; Greenwood, Paul L.; Hiendleder, Stefan

    2013-01-01

    Postnatal myofibre characteristics and muscle mass are largely determined during fetal development and may be significantly affected by epigenetic parent-of-origin effects. However, data on such effects in prenatal muscle development that could help understand unexplained variation in postnatal muscle traits are lacking. In a bovine model we studied effects of distinct maternal and paternal genomes, fetal sex, and non-genetic maternal effects on fetal myofibre characteristics and muscle mass. Data from 73 fetuses (Day153, 54% term) of four genetic groups with purebred and reciprocal cross Angus and Brahman genetics were analyzed using general linear models. Parental genomes explained the greatest proportion of variation in myofibre size of Musculus semitendinosus (80–96%) and in absolute and relative weights of M. supraspinatus, M. longissimus dorsi, M. quadriceps femoris and M. semimembranosus (82–89% and 56–93%, respectively). Paternal genome in interaction with maternal genome (P<0.05) explained most genetic variation in cross sectional area (CSA) of fast myotubes (68%), while maternal genome alone explained most genetic variation in CSA of fast myofibres (93%, P<0.01). Furthermore, maternal genome independently (M. semimembranosus, 88%, P<0.0001) or in combination (M. supraspinatus, 82%; M. longissimus dorsi, 93%; M. quadriceps femoris, 86%) with nested maternal weight effect (5–6%, P<0.05), was the predominant source of variation for absolute muscle weights. Effects of paternal genome on muscle mass decreased from thoracic to pelvic limb and accounted for all (M. supraspinatus, 97%, P<0.0001) or most (M. longissimus dorsi, 69%, P<0.0001; M. quadriceps femoris, 54%, P<0.001) genetic variation in relative weights. An interaction between maternal and paternal genomes (P<0.01) and effects of maternal weight (P<0.05) on expression of H19, a master regulator of an imprinted gene network, and negative correlations between H19 expression and fetal muscle mass

  11. A mouse anti-myostatin antibody increases muscle mass and improves muscle strength and contractility in the mdx mouse model of Duchenne muscular dystrophy and its humanized equivalent, domagrozumab (PF-06252616), increases muscle volume in cynomolgus monkeys.

    PubMed

    St Andre, Michael; Johnson, Mark; Bansal, Prashant N; Wellen, Jeremy; Robertson, Andrew; Opsahl, Alan; Burch, Peter M; Bialek, Peter; Morris, Carl; Owens, Jane

    2017-11-09

    The treatments currently approved for Duchenne muscular dystrophy (DMD), a progressive skeletal muscle wasting disease, address the needs of only a small proportion of patients resulting in an urgent need for therapies that benefit all patients regardless of the underlying mutation. Myostatin is a member of the transforming growth factor-β (TGF-β) family of ligands and is a negative regulator of skeletal muscle mass. Loss of myostatin has been shown to increase muscle mass and improve muscle function in both normal and dystrophic mice. Therefore, myostatin blockade via a specific antibody could ameliorate the muscle weakness in DMD patients by increasing skeletal muscle mass and function, thereby reducing patients' functional decline. A murine anti-myostatin antibody, mRK35, and its humanized analog, domagrozumab, were developed and their ability to inhibit several TGB-β ligands was measured using a cell-based Smad-activity reporter system. Normal and mdx mice were treated with mRK35 to examine the antibody's effect on body weight, lean mass, muscle weights, grip strength, ex vivo force production, and fiber size. The humanized analog (domagrozumab) was tested in non-human primates (NHPs) for changes in skeletal muscle mass and volume as well as target engagement via modulation of circulating myostatin. Both the murine and human antibodies are specific and potent inhibitors of myostatin and GDF11. mRK35 is able to increase body weight, lean mass, and muscle weights in normal mice. In mdx mice, mRK35 significantly increased body weight, muscle weights, grip strength, and ex vivo force production in the extensor digitorum longus (EDL) muscle. Further, tibialis anterior (TA) fiber size was significantly increased. NHPs treated with domagrozumab demonstrated a dose-dependent increase in lean mass and muscle volume and exhibited increased circulating levels of myostatin demonstrating target engagement. We demonstrated that the potent anti-myostatin antibody mRK35 and

  12. Effects of long term supplementation of anabolic androgen steroids on human skeletal muscle.

    PubMed

    Yu, Ji-Guo; Bonnerud, Patrik; Eriksson, Anders; Stål, Per S; Tegner, Yelverton; Malm, Christer

    2014-01-01

    The effects of long-term (over several years) anabolic androgen steroids (AAS) administration on human skeletal muscle are still unclear. In this study, seventeen strength training athletes were recruited and individually interviewed regarding self-administration of banned substances. Ten subjects admitted having taken AAS or AAS derivatives for the past 5 to 15 years (Doped) and the dosage and type of banned substances were recorded. The remaining seven subjects testified to having never used any banned substances (Clean). For all subjects, maximal muscle strength and body composition were tested, and biopsies from the vastus lateralis muscle were obtained. Using histochemistry and immunohistochemistry (IHC), muscle biopsies were evaluated for morphology including fiber type composition, fiber size, capillary variables and myonuclei. Compared with the Clean athletes, the Doped athletes had significantly higher lean leg mass, capillary per fibre and myonuclei per fiber. In contrast, the Doped athletes had significantly lower absolute value in maximal squat force and relative values in maximal squat force (relative to lean body mass, to lean leg mass and to muscle fiber area). Using multivariate statistics, an orthogonal projection of latent structure discriminant analysis (OPLS-DA) model was established, in which the maximal squat force relative to muscle mass and the maximal squat force relative to fiber area, together with capillary density and nuclei density were the most important variables for separating Doped from the Clean athletes (regression  =  0.93 and prediction  =  0.92, p<0.0001). In Doped athletes, AAS dose-dependent increases were observed in lean body mass, muscle fiber area, capillary density and myonuclei density. In conclusion, long term AAS supplementation led to increases in lean leg mass, muscle fiber size and a parallel improvement in muscle strength, and all were dose-dependent. Administration of AAS may induce sustained

  13. Effects of Long Term Supplementation of Anabolic Androgen Steroids on Human Skeletal Muscle

    PubMed Central

    Yu, Ji-Guo; Bonnerud, Patrik; Eriksson, Anders; Stål, Per S.; Tegner, Yelverton; Malm, Christer

    2014-01-01

    The effects of long-term (over several years) anabolic androgen steroids (AAS) administration on human skeletal muscle are still unclear. In this study, seventeen strength training athletes were recruited and individually interviewed regarding self-administration of banned substances. Ten subjects admitted having taken AAS or AAS derivatives for the past 5 to 15 years (Doped) and the dosage and type of banned substances were recorded. The remaining seven subjects testified to having never used any banned substances (Clean). For all subjects, maximal muscle strength and body composition were tested, and biopsies from the vastus lateralis muscle were obtained. Using histochemistry and immunohistochemistry (IHC), muscle biopsies were evaluated for morphology including fiber type composition, fiber size, capillary variables and myonuclei. Compared with the Clean athletes, the Doped athletes had significantly higher lean leg mass, capillary per fibre and myonuclei per fiber. In contrast, the Doped athletes had significantly lower absolute value in maximal squat force and relative values in maximal squat force (relative to lean body mass, to lean leg mass and to muscle fiber area). Using multivariate statistics, an orthogonal projection of latent structure discriminant analysis (OPLS-DA) model was established, in which the maximal squat force relative to muscle mass and the maximal squat force relative to fiber area, together with capillary density and nuclei density were the most important variables for separating Doped from the Clean athletes (regression  =  0.93 and prediction  =  0.92, p<0.0001). In Doped athletes, AAS dose-dependent increases were observed in lean body mass, muscle fiber area, capillary density and myonuclei density. In conclusion, long term AAS supplementation led to increases in lean leg mass, muscle fiber size and a parallel improvement in muscle strength, and all were dose-dependent. Administration of AAS may induce sustained

  14. Myosin heavy chain expression in rodent skeletal muscle: effects of exposure to zero gravity

    NASA Technical Reports Server (NTRS)

    Haddad, F.; Herrick, R. E.; Adams, G. R.; Baldwin, K. M.

    1993-01-01

    This study ascertained the effects of 9 days of zero gravity on the relative (percentage of total) and calculated absolute (mg/muscle) content of isomyosin expressed in both antigravity and locomotor skeletal muscle of ground control (CON) and flight-exposed (FL) rats. Results showed that although there were no differences in body weight between FL and CON animals, a significant reduction in muscle mass occurred in the vastus intermedius (VI) (P < 0.05) but not in the vastus lateralis (VL) or the tibialis anterior. Both total muscle protein and myofibril protein content were not different between the muscle regions examined in the FL and CON groups. In the VI, there were trends for reductions in the relative content of type I and IIa myosin heavy chains (MHCs) that were offset by increases in the relative content of both type IIb and possibly type IIx MHC protein (P > 0.05). mRNA levels were consistent with this pattern (P < 0.05). The same pattern held true for the red region of the VL as examined at both the protein and mRNA level (P < 0.05). When the atrophy process was examined, there were net reductions in the absolute content of both type I and IIa MHCs that were offset by calculated increases in type IIb MHC in both VI and red VL. Collectively, these findings suggest that there are both absolute and relative changes occurring in MHC expression in the "red" regions of antigravity skeletal muscle during exposure to zero gravity that could affect muscle function.

  15. Low skeletal muscle mass outperforms the Charlson Comorbidity Index in risk prediction in patients undergoing pancreatic resections.

    PubMed

    Wagner, D; Marsoner, K; Tomberger, A; Haybaeck, J; Haas, J; Werkgartner, G; Cerwenka, H; Bacher, H; Mischinger, H J; Kornprat, P

    2018-05-01

    Low skeletal muscle mass is a known predictor of morbidity and mortality in patients undergoing major pancreatic surgeries. We sought to combine low skeletal muscle mass with established risk predictors to improve their prognostic capacity for postoperative outcome and morbidity. As established parameters to predict preoperative mortality risk for patients, the ASA classification and the Charlson Comorbidity Index (CCI) were used. The Hounsfield Units Average Calculation (HUAC) was measured to define low skeletal muscle mass in 424 patients undergoing pancreatic resections for malignancies. Patients in the lowest sex-adjusted quartile for HUAC were defined as having low skeletal muscle mass (muscle wasting). Multivariable Cox regression analysis was utilized to identify preoperative risk factors associated with postoperative morbidity. Median patient age was 63 years (19-87), 47.9% patients were male, and half the cohort had multiple comorbidities (Charlson Comorbidity Index [CCI]>6, 63.2%), 30-day mortality was 5.8% (n = 25). Median HUAC was 19.78 HU (IQR: 15.94-23.54) with 145 patients (34.2%) having low skeletal muscle mass. Preoperative frailty defined by low skeletal muscle mass was associated with an increased risk for postoperative complications (OR 1.55, CI 95% 0.98-2.45, p = 0.014), and a higher 30-day mortality (HR 5.17, CI 95% 1.57-16.69, p = 0.004). With an AUC of 0.85 HUAC showed the highest predictability for 30-day mortality (CI 95% 0.78-0.91, p = 0.0001). Patients with CCI ≥6 and low skeletal muscle mass defined by the HUAC had a 9.78 higher risk of dying in the immediate postoperative phase (HR 9.78, CI 95% 2.98-12.2, p = 0.0001). Low skeletal muscle mass predicts postoperative mortality and complications best and it should be incorporated to conventional risk scores to identify high risk patients. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights

  16. Sulfur-based absolute quantification of proteins using isotope dilution inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lee, Hyun-Seok; Heun Kim, Sook; Jeong, Ji-Seon; Lee, Yong-Moon; Yim, Yong-Hyeon

    2015-10-01

    An element-based reductive approach provides an effective means of realizing International System of Units (SI) traceability for high-purity biological standards. Here, we develop an absolute protein quantification method using double isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS) combined with microwave-assisted acid digestion for the first time. We validated the method and applied it to certify the candidate protein certified reference material (CRM) of human growth hormone (hGH). The concentration of hGH was determined by analysing the total amount of sulfur in hGH. Next, the size-exclusion chromatography method was used with ICP-MS to characterize and quantify sulfur-containing impurities. By subtracting the contribution of sulfur-containing impurities from the total sulfur content in the hGH CRM, we obtained a SI-traceable certification value. The quantification result obtained with the present method based on sulfur analysis was in excellent agreement with the result determined via a well-established protein quantification method based on amino acid analysis using conventional acid hydrolysis combined with an ID liquid chromatography-tandem mass spectrometry. The element-based protein quantification method developed here can be generally used for SI-traceable absolute quantification of proteins, especially pure-protein standards.

  17. Total-body creatine pool size and skeletal muscle mass determination by creatine-(methyl-D3) dilution in rats.

    PubMed

    Stimpson, Stephen A; Turner, Scott M; Clifton, Lisa G; Poole, James C; Mohammed, Hussein A; Shearer, Todd W; Waitt, Greg M; Hagerty, Laura L; Remlinger, Katja S; Hellerstein, Marc K; Evans, William J

    2012-06-01

    There is currently no direct, facile method to determine total-body skeletal muscle mass for the diagnosis and treatment of skeletal muscle wasting conditions such as sarcopenia, cachexia, and disuse. We tested in rats the hypothesis that the enrichment of creatinine-(methyl-d(3)) (D(3)-creatinine) in urine after a defined oral tracer dose of D(3)-creatine can be used to determine creatine pool size and skeletal muscle mass. We determined 1) an oral tracer dose of D(3)-creatine that was completely bioavailable with minimal urinary spillage and sufficient enrichment in the body creatine pool for detection of D(3)-creatine in muscle and D(3)-creatinine in urine, and 2) the time to isotopic steady state. We used cross-sectional studies to compare total creatine pool size determined by the D(3)-creatine dilution method to lean body mass determined by independent methods. The tracer dose of D(3)-creatine (<1 mg/rat) was >99% bioavailable with 0.2-1.2% urinary spillage. Isotopic steady state was achieved within 24-48 h. Creatine pool size calculated from urinary D(3)-creatinine enrichment at 72 h significantly increased with muscle accrual in rat growth, significantly decreased with dexamethasone-induced skeletal muscle atrophy, was correlated with lean body mass (r = 0.9590; P < 0.0001), and corresponded to predicted total muscle mass. Total-body creatine pool size and skeletal muscle mass can thus be accurately and precisely determined by an orally delivered dose of D(3)-creatine followed by the measurement of D(3)-creatinine enrichment in a single urine sample and is promising as a noninvasive tool for the clinical determination of skeletal muscle mass.

  18. Recovery of skeletal muscle mass after extensive injury: positive effects of increased contractile activity.

    PubMed

    Richard-Bulteau, Hélène; Serrurier, Bernard; Crassous, Brigitte; Banzet, Sébastien; Peinnequin, André; Bigard, Xavier; Koulmann, Nathalie

    2008-02-01

    The present study was designed to test the hypothesis that increasing physical activity by running exercise could favor the recovery of muscle mass after extensive injury and to determine the main molecular mechanisms involved. Left soleus muscles of female Wistar rats were degenerated by notexin injection before animals were assigned to either a sedentary group or an exercised group. Both regenerating and contralateral intact muscles from active and sedentary rats were removed 5, 7, 14, 21, 28 and 42 days after injury (n = 8 rats/group). Increasing contractile activity through running exercise during muscle regeneration ensured the full recovery of muscle mass and muscle cross-sectional area as soon as 21 days after injury, whereas muscle weight remained lower even 42 days postinjury in sedentary rats. Proliferator cell nuclear antigen and MyoD protein expression went on longer in active rats than in sedentary rats. Myogenin protein expression was higher in active animals than in sedentary animals 21 days postinjury. The Akt-mammalian target of rapamycin (mTOR) pathway was activated early during the regeneration process, with further increases of mTOR phosphorylation and its downstream effectors, eukaryotic initiation factor-4E-binding protein-1 and p70(s6k), in active rats compared with sedentary rats (days 7-14). The exercise-induced increase in mTOR phosphorylation, independently of Akt, was associated with decreased levels of phosphorylated AMP-activated protein kinase. Taken together, these results provided evidence that increasing contractile activity during muscle regeneration ensured early and full recovery of muscle mass and suggested that these beneficial effects may be due to a longer proliferative step of myogenic cells and activation of mTOR signaling, independently of Akt, during the maturation step of muscle regeneration.

  19. Absolute calibration of the mass scale in the inverse problem of the physical theory of fireballs

    NASA Astrophysics Data System (ADS)

    Kalenichenko, V. V.

    1992-08-01

    A method of the absolute calibration of the mass scale is proposed for solving the inverse problem of the physical theory of fireballs. The method is based on data on the masses of fallen meteorites whose fireballs have been photographed in flight. The method can be applied to fireballs whose bodies have not experienced significant fragmentation during their flight in the atmosphere and have kept their shape relatively well. Data on the Lost City and Innisfree meteorites are used to calculate the calibration coefficients.

  20. Skeletal muscle mass is associated with severe dysphagia in cancer patients

    PubMed Central

    Wakabayashi, Hidetaka; Matsushima, Masato; Uwano, Rimiko; Watanabe, Naoko; Oritsu, Hideyuki; Shimizu, Yoshitaka

    2015-01-01

    Background The purpose of this study was to assess the association between skeletal muscle mass, activities of daily living (ADLs) and severe dysphagia in cancer patients. Methods A nested case-control study was performed in 111 consecutive cancer patients with dysphagia who were prescribed speech therapy. Skeletal muscle mass comprising the cross-sectional area of the left and right psoas muscles was assessed via abdominal computed tomography at the third lumbar vertebral level. ADLs were evaluated by the Barthel Index. The severity of dysphagia was assessed by the Food Intake Level Scale and was characterized by non-oral feeding or oral food intake at discharge. Univariate and logistic regression analyses were applied to examine the associations between dysphagia, skeletal muscle index (SMI) and ADLs. Results There were 86 men and 25 women (mean age, 70 years). The mean SMI was 5.68 ± 1.74 cm2/m2 in men and 4.43 ± 1.21 cm2/m2 in women. The median Barthel Index score was 20. Thirty-three patients were on non-oral feeding at discharge. The mean SMI did not differ significantly between non-oral feeding and oral food intake groups in t-test. The median Barthel Index score was lower in the non-oral feeding group in Mann–Whitney U test. Logistic regression analysis of the severity of dysphagia adjusted for age, sex, SMI, Barthel Index score, serum albumin, cancer type and stage, and vocal cord paralysis showed that SMI was associated independently with oral food intake at discharge. Barthel Index score showed a tendency to be associated with oral food intake. Conclusions Skeletal muscle mass is associated with severe dysphagia in cancer patients. ADLs show a tendency to be associated with severe dysphagia in cancer patients. PMID:26673551

  1. Strength and muscle mass loss with aging process. Age and strength loss.

    PubMed

    Keller, Karsten; Engelhardt, Martin

    2013-10-01

    aging process is associated with changes in muscle mass and strength with decline of muscle strength after the 30(th) life year. The aim of this study was to investigate these changes in muscle mass and strength. for this analysis 26 participants were subdivided in two groups. Group 1 comprises participants aged <40 years (n=14), group 2 those >40 years (n=12). We assessed anthropometrics, range of motions, leg circumferences and isometric strength values of the knee joints. besides comparable anthropometrics, circumferences and strength were higher in group 1 than in group 2. Circumference of upper leg (20 cm above knee articular space) showed for right leg a trend to a significant (median: 54.45 cm (1(st) quartile: 49.35/3(rd) quartile: 57.78) vs 49.80 cm (49.50/50.75), p=0.0526) and for left leg a significant 54.30 cm (49.28/58.13) vs 49.50 cm (48.00/52.53), p=0.0356) larger circumference in group 1. Isometric strength was in 60° knee flexion significantly higher in group 1 than in group 2 for right (729.88N (561.47/862.13) vs 456.92N (304.67/560.12), p=0.00448) and left leg (702.49N (581.36/983.87) vs 528.49N (332.95/648.58), p=0.0234). aging process leads to distinct muscle mass and strength loss. Muscle strength declines from people aged <40 years to those >40 years between 16.6% and 40.9%.

  2. Within-Winter Flexibility in Muscle Masses, Myostatin, and Cellular Aerobic Metabolic Intensity in Passerine Birds.

    PubMed

    Swanson, David L; King, Marisa O; Culver, William; Zhang, Yufeng

    Metabolic rates of passerine birds are flexible traits that vary both seasonally and among and within winters. Seasonal variation in summit metabolic rates (M sum = maximum thermoregulatory metabolism) in birds is consistently correlated with changes in pectoralis muscle and heart masses and sometimes with variation in cellular aerobic metabolic intensity, so these traits might also be associated with shorter-term, within-winter variation in metabolic rates. To determine whether these mechanisms are associated with within-winter variation in M sum , we examined the effects of short-term (ST; 0-7 d), medium-term (MT; 14-30 d), and long-term (LT; 30-yr means) temperature variables on pectoralis muscle and heart masses, pectoralis expression of the muscle-growth inhibitor myostatin and its metalloproteinase activators TLL-1 and TLL-2, and pectoralis and heart citrate synthase (CS; an indicator of cellular aerobic metabolic intensity) activities for two temperate-zone resident passerines, house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis). For both species, pectoralis mass residuals were positively correlated with ST temperature variables, suggesting that cold temperatures resulted in increased turnover of pectoralis muscle, but heart mass showed little within-winter variation for either species. Pectoralis mRNA and protein expression of myostatin and the TLLs were only weakly correlated with ST and MT temperature variables, which is largely consistent with trends in muscle masses for both species. Pectoralis and heart CS activities showed weak and variable trends with ST temperature variables in both species, suggesting only minor effects of temperature variation on cellular aerobic metabolic intensity. Thus, neither muscle or heart masses, regulation by the myostatin system, nor cellular aerobic metabolic intensity varied consistently with winter temperature, suggesting that other factors regulate within-winter metabolic variation in these birds.

  3. Insulin Resistance Negatively Influences the Muscle-Dependent IGF-1-Bone Mass Relationship in Premenarcheal Girls.

    PubMed

    Kindler, J M; Pollock, N K; Laing, E M; Jenkins, N T; Oshri, A; Isales, C; Hamrick, M; Lewis, R D

    2016-01-01

    IGF-1 promotes bone growth directly and indirectly through its effects on skeletal muscle. Insulin and IGF-1 share a common cellular signaling process; thus, insulin resistance may influence the IGF-1-muscle-bone relationship. We sought to determine the effect of insulin resistance on the muscle-dependent relationship between IGF-1 and bone mass in premenarcheal girls. This was a cross-sectional study conducted at a university research center involving 147 girls ages 9 to 11 years. Glucose, insulin, and IGF-1 were measured from fasting blood samples. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated from glucose and insulin. Fat-free soft tissue (FFST) mass and bone mineral content (BMC) were measured by dual-energy x-ray absorptiometry. Our primary outcome was BMC/height. In our path model, IGF-1 predicted FFST mass (b = 0.018; P = .001), which in turn predicted BMC/height (b = 0.960; P < .001). IGF-1 predicted BMC/height (b = 0.001; P = .002), but not after accounting for the mediator of this relationship, FFST mass. The HOMA-IR by IGF-1 interaction negatively predicted FFST mass (b = -0.044; P = .034). HOMA-IR had a significant and negative effect on the muscle-dependent relationship between IGF-1 and BMC/height (b = -0.151; P = .047). Lean body mass is an important intermediary factor in the IGF-1-bone relationship. For this reason, bone development may be compromised indirectly via suboptimal IGF-1-dependent muscle development in insulin-resistant children.

  4. Systemic SMAD7 Gene Therapy Increases Striated Muscle Mass and Enhances Exercise Capacity in a Dose-Dependent Manner.

    PubMed

    Maricelli, Joseph W; Bishaw, Yemeserach M; Wang, Bo; Du, Min; Rodgers, Buel D

    2018-03-01

    Striated muscle wasting occurs with a variety of disease indications, contributing to mortality and compromising life quality. Recent studies indicate that the recombinant adeno-associated virus (serotype 6) Smad7 gene therapeutic, AVGN7, enhances skeletal and cardiac muscle mass and prevents cancer-induced wasting of both tissues. This is accomplished by attenuating ActRIIb intracellular signaling and, as a result, the physiological actions of myostatin and other ActRIIb ligands. AVGN7 also enhances isolated skeletal muscle twitch force, but is unknown to improve systemic muscle function similarly, especially exercise capacity. A 2-month-long dose-escalation study was therefore conducted using 5 × 10 11 , 1 × 10 12 , and 5 × 10 12 vg/mouse and different tests of systemic muscle function. Body mass, skeletal muscle mass, heart mass, and forelimb grip strength were all increased in a dose-dependent manner, as was the fiber cross-sectional area of tibialis anterior muscles. Maximal oxygen consumption (VO 2 max), a measure of metabolic rate, was similarly enhanced during forced treadmill running, and although the total distance traveled was only elevated by the highest dose, all doses reduced the energy expenditure rate compared to control mice injected with an empty vector. Such improvements in VO 2 max are consistent with physiological cardiac hypertrophy, which is highly beneficial and a normal adaptive response to exercise. This was particularly evident at the lowest dose tested, which had minimal significant effects on skeletal muscle mass and/or function, but increased heart weight and exercise capacity. These results together suggest that AVGN7 enhances striated muscle mass and systemic muscle function. They also define minimally effective and optimal doses for future preclinical trials and toxicology studies and in turn will aid in establishing dose ranges for clinical trials.

  5. Pro-inflammatory capacity of classically activated monocytes relates positively to muscle mass and strength.

    PubMed

    Beenakker, Karel G M; Westendorp, Rudi G J; de Craen, Anton J M; Slagboom, Pieternella E; van Heemst, Diana; Maier, Andrea B

    2013-08-01

    In mice, monocytes that exhibit a pro-inflammatory profile enter muscle tissue after muscle injury and are crucial for clearance of necrotic tissue and stimulation of muscle progenitor cell proliferation and differentiation. The aim of this study was to test if pro-inflammatory capacity of classically activated (M1) monocytes relates to muscle mass and strength in humans. This study included 191 male and 195 female subjects (mean age 64.2 years (SD 6.4) and 61.9 ± 6.4, respectively) of the Leiden Longevity Study. Pro-inflammatory capacity of M1 monocytes was assessed by ex vivo stimulation of whole blood with Toll-like receptor (TLR) 4 agonist lipopolysaccharide (LPS) and TLR-2/1 agonist tripalmitoyl-S-glycerylcysteine (Pam₃Cys-SK₄), both M1 phenotype activators. Cytokines that stimulate M1 monocyte response (IFN-γ and GM-CSF) as well as cytokines that are secreted by M1 monocytes (IL-6, TNF-α, IL-12, and IL-1β) were measured. Analyses were adjusted for age, height, and body fat mass. Upon stimulation with LPS, the cytokine production capacity of INF-γ, GM-CSF, and TNF-α was significantly positively associated with lean body mass, appendicular lean mass and handgrip strength in men, but not in women. Upon stimulation with Pam₃Cys-SK₄, IL-6; TNF-α; and Il-1β were significantly positively associated with lean body mass and appendicular lean in women, but not in men. Taken together, this study shows that higher pro-inflammatory capacity of M1 monocytes upon stimulation is associated with muscle characteristics and sex dependent. © 2013 John Wiley & Sons Ltd and the Anatomical Society.

  6. Baseline Muscle Mass Is a Poor Predictor of Functional Overload-Induced Gain in the Mouse Model

    PubMed Central

    Kilikevicius, Audrius; Bunger, Lutz; Lionikas, Arimantas

    2016-01-01

    Genetic background contributes substantially to individual variability in muscle mass. Muscle hypertrophy in response to resistance training can also vary extensively. However, it is less clear if muscle mass at baseline is predictive of the hypertrophic response. The aim of this study was to examine the effect of genetic background on variability in muscle mass at baseline and in the adaptive response of the mouse fast- and slow-twitch muscles to overload. Males of eight laboratory mouse strains: C57BL/6J (B6, n = 17), BALB/cByJ (n = 7), DBA/2J (D2, n = 12), B6.A-(rs3676616-D10Utsw1)/Kjn (B6.A, n = 9), C57BL/6J-Chr10A/J/NaJ (B6.A10, n = 8), BEH+/+ (n = 11), BEH (n = 12), and DUHi (n = 12), were studied. Compensatory growth of soleus and plantaris muscles was triggered by a 4-week overload induced by synergist unilateral ablation. Muscle weight in the control leg (baseline) varied from 5.2 ± 07 mg soleus and 11.4 ± 1.3 mg plantaris in D2 mice to 18.0 ± 1.7 mg soleus in DUHi and 43.7 ± 2.6 mg plantaris in BEH (p < 0.001 for both muscles). In addition, soleus in the B6.A10 strain was ~40% larger (p < 0.001) compared to the B6. Functional overload increased muscle weight, however, the extent of gain was strain-dependent for both soleus (p < 0.01) and plantaris (p < 0.02) even after accounting for the baseline differences. For the soleus muscle, the BEH strain emerged as the least responsive, with a 1.3-fold increase, compared to a 1.7-fold gain in the most responsive D2 strain, and there was no difference in the gain between the B6.A10 and B6 strains. The BEH strain appeared the least responsive in the gain of plantaris as well, 1.3-fold, compared to ~1.5-fold gain in the remaining strains. We conclude that variation in muscle mass at baseline is not a reliable predictor of that in the overload-induced gain. This suggests that a different set of genes influence variability in muscle mass acquired in the process of normal development, growth, and maintenance, and

  7. Androgen signaling in myocytes contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue.

    PubMed

    Ophoff, Jill; Van Proeyen, Karen; Callewaert, Filip; De Gendt, Karel; De Bock, Katrien; Vanden Bosch, An; Verhoeven, Guido; Hespel, Peter; Vanderschueren, Dirk

    2009-08-01

    Muscle frailty is considered a major cause of disability in the elderly and chronically ill. However, the exact role of androgen receptor (AR) signaling in muscle remains unclear. Therefore, a postmitotic myocyte-specific AR knockout (mARKO) mouse model was created and investigated together with a mouse model with ubiquitous AR deletion. Muscles from mARKO mice displayed a marked reduction in AR protein (60-88%). Interestingly, body weights and lean body mass were lower in mARKO vs. control mice (-8%). The weight of the highly androgen-sensitive musculus levator ani was significantly reduced (-46%), whereas the weights of other peripheral skeletal muscles were not or only slightly reduced. mARKO mice had lower intra-abdominal fat but did not demonstrate a cortical or trabecular bone phenotype, indicating that selective ablation of the AR in myocytes affected male body composition but not skeletal homeostasis. Furthermore, muscle contractile performance in mARKO mice did not differ from their controls. Myocyte-specific AR ablation resulted in a conversion of fast toward slow fibers, without affecting muscle strength or fatigue. Similar results were obtained in ubiquitous AR deletion, showing lower body weight, whereas some but not all muscle weights were reduced. The percent slow fibers was increased, but no changes in muscle strength or fatigue could be detected. Together, our findings show that myocyte AR signaling contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue. The levator ani weight remains the most sensitive and specific marker of AR-mediated anabolic action on muscle.

  8. 40 CFR Appendix I to Subpart A of... - Global Warming Potentials (Mass Basis), Referenced to the Absolute GWP for the Adopted Carbon...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Global Warming Potentials (Mass Basis), Referenced to the Absolute GWP for the Adopted Carbon Cycle Model CO2 Decay Response and Future CO2... Absolute GWP for the Adopted Carbon Cycle Model CO2 Decay Response and Future CO2 Atmospheric...

  9. Alfacalcidol improves muscle power, muscle function and balance in elderly patients with reduced bone mass.

    PubMed

    Schacht, E; Ringe, Johann D

    2012-01-01

    We investigated the effect of daily therapy with 1 mcg alfacalcidol (Doss(®)-TEVA/AWD-pharma) on muscle power, muscle function, balance performance and fear of falls in an open, multi-centered, uncontrolled, prospective study on a cohort of patients with reduced bone mass. Among the 2,097 participants, 87.1% were post-menopausal women and 12.9% were men. Mean age was 74.8 years and mean body mass index (BMI) 26.3 kg/m². A total of 75.3% of the study population had osteoporosis, 81% a diagnosis of "increased risk of falls" and 70.1% had a creatinine clearance (CrCl) of <65 ml/min. Participants underwent muscle function and muscle power tests at onset and after 3 and 6 months: the timed up and go test (TUG) and the chair rising test (CRT). At baseline and after 6 months, participants performed the tandem gait test (TGT) and filled out a questionnaire evaluating fear of falling. Successful performance in the muscle tests is associated with a significantly lower risk of falls and non-vertebral fractures in elderly patients (successful test performance: TUG ≤ 10 s (sec), CRT ≤ 10 s, TGT ≥ 8 steps). A significant improvement in the performance of the two muscle tests was proved already after 3 months of treatment with alfacalcidol and further increased by the end of the therapeutic intervention. There were significant increases in the number of participants able to successfully perform the tests: 24.6% at baseline and 46.3% at the end of trial for the TUG (P < 0.0001) and 21.7% at baseline and 44.2% at the end for the CRT test (P = 0.0001). The mean time used for the TUG was decreased by 3.0 s from the average onset value of 17.0 s and by 3.1 s from the initial average 16.5 s for the CRT. The percentage of participants able to perform the balance test (TGT) increased from 36.0% at onset to 58.6% at the end of the trial (P < 0.0001). An increased fear of falling was reduced by the end of the study in 74.4% of the patients. Throughout the study, there were 26

  10. Antibody-directed myostatin inhibition enhances muscle mass and function in tumor-bearing mice.

    PubMed

    Murphy, Kate T; Chee, Annabel; Gleeson, Ben G; Naim, Timur; Swiderski, Kristy; Koopman, René; Lynch, Gordon S

    2011-09-01

    Cancer cachexia describes the progressive skeletal muscle wasting and weakness in many cancer patients and accounts for >20% of cancer-related deaths. We tested the hypothesis that antibody-directed myostatin inhibition would attenuate the atrophy and loss of function in muscles of tumor-bearing mice. Twelve-week-old C57BL/6 mice received a subcutaneous injection of saline (control) or Lewis lung carcinoma (LLC) tumor cells. One week later, mice received either once weekly injections of saline (control, n = 12; LLC, n = 9) or a mouse chimera of anti-human myostatin antibody (PF-354, 10 mg·kg⁻¹·wk⁻¹, LLC+PF-354, n = 11) for 5 wk. Injection of LLC cells reduced muscle mass and maximum force of tibialis anterior (TA) muscles by 8-10% (P < 0.05), but the muscle atrophy and weakness were prevented with PF-354 treatment (P > 0.05). Maximum specific (normalized) force of diaphragm muscle strips was reduced with LLC injection (P < 0.05) but was not improved with PF-354 treatment (P > 0.05). PF-354 enhanced activity of oxidative enzymes in TA and diaphragm muscles of tumor-bearing mice by 118% and 89%, respectively (P < 0.05). Compared with controls, apoptosis that was not of myofibrillar or satellite cell origin was 140% higher in TA muscle cross sections from saline-treated LLC tumor-bearing mice (P < 0.05) but was not different in PF-354-treated tumor-bearing mice (P > 0.05). Antibody-directed myostatin inhibition attenuated the skeletal muscle atrophy and loss of muscle force-producing capacity in a murine model of cancer cachexia, in part by reducing apoptosis. The improvements in limb muscle mass and function highlight the therapeutic potential of antibody-directed myostatin inhibition for cancer cachexia.

  11. The effect of obesity on the contractile performance of isolated mouse soleus, EDL, and diaphragm muscles.

    PubMed

    Tallis, Jason; Hill, Cameron; James, Rob S; Cox, Val M; Seebacher, Frank

    2017-01-01

    Obesity affects the major metabolic and cellular processes involved in skeletal muscle contractility. Surprisingly, the effect of obesity on isolated skeletal muscle performance remains unresolved. The present study is the first to examine the muscle-specific changes in contractility following dietary-induced obesity using an isolated muscle work-loop (WL) model that more closely represents in vivo muscle performance. Following 16-wk high-calorific feeding, soleus (SOL), extensor digitorum longus (EDL), and diaphragm (DIA) were isolated from female (CD-1) mice, and contractile performance was compared against a lean control group. Obese SOL produced greater isometric force; however, isometric stress (force per unit muscle area), absolute WL power, and normalized WL power (watts per kilogram muscle mass) were unaffected. Maximal isometric force and absolute WL power of the EDL were similar between groups. For both EDL and DIA, isometric stress and normalized WL power were reduced in the obese groups. Obesity caused a significant reduction in fatigue resistance in all cases. Our findings demonstrate a muscle-specific reduction in contractile performance and muscle quality that is likely related to in vivo mechanical role, fiber type, and metabolic profile, which may in part be related to changes in myosin heavy chain expression and AMP-activated protein kinase activity. These results infer that, beyond the additional requirement of moving a larger body mass, functional performance and quality of life may be further limited by poor muscle function in obese individuals. As such, a reduction in muscle performance may be a substantial contributor to the negative cycle of obesity. The effect of obesity on isolated muscle function is surprisingly underresearched. The present study is the first to examine the effects of obesity on isolated muscle performance using a method that more closely represents real-world muscle function. This work uniquely establishes a muscle

  12. Effect of constitutive inactivation of the myostatin gene on the gain in muscle strength during postnatal growth in two murine models.

    PubMed

    Stantzou, Amalia; Ueberschlag-Pitiot, Vanessa; Thomasson, Remi; Furling, Denis; Bonnieu, Anne; Amthor, Helge; Ferry, Arnaud

    2017-02-01

    The effect of constitutive inactivation of the gene encoding myostatin on the gain in muscle performance during postnatal growth has not been well characterized. We analyzed 2 murine myostatin knockout (KO) models, (i) the Lee model (KO Lee ) and (ii) the Grobet model (KO Grobet ), and measured the contraction of tibialis anterior muscle in situ. Absolute maximal isometric force was increased in 6-month-old KO Lee and KO Grobet mice, as compared to wild-type mice. Similarly, absolute maximal power was increased in 6-month-old KO Lee mice. In contrast, specific maximal force (relative maximal force per unit of muscle mass was decreased in all 6-month-old male and female KO mice, except in 6-month-old female KO Grobet mice, whereas specific maximal power was reduced only in male KO Lee mice. Genetic inactivation of myostatin increases maximal force and power, but in return it reduces muscle quality, particularly in male mice. Muscle Nerve 55: 254-261, 2017. © 2016 Wiley Periodicals, Inc.

  13. Changing the Bayesian prior: Absolute neutrino mass constraints in nonlocal gravity*

    NASA Astrophysics Data System (ADS)

    Dirian, Yves

    2017-10-01

    Prior change is discussed in observational constraints studies of nonlocally modified gravity, where a model characterized by a modification of the form ˜m2R □-2R to the Einstein-Hilbert action was compared against the base Λ CDM one in a Bayesian way. It was found that the competing modified gravity model is significantly disfavored (at 22 ∶1 in terms of betting-odds) against Λ CDM given CMB +SNIa +BAO data, because of a tension appearing in the H0- ΩM plane. We identify the underlying mechanism generating such a tension and show that it is mostly caused by the late-time, quite smooth, phantom nature of the effective dark energy described by the nonlocal model. We find that the tension is resolved by considering an extension of the initial baseline, consisting in allowing the absolute mass of three degenerated massive neutrino species ∑mν/3 to take values within a prior interval consistent with existing data. As a net effect, the absolute neutrino mass is inferred to be nonvanishing at 2 σ level, best-fitting at ∑mν≈0.21 eV , and the Bayesian tension disappears rendering the nonlocal gravity model statistically equivalent to Λ CDM , given recent CMB +SNIa +BAO data. We also discuss constraints from growth rate measurements f σ8, whose fit is found to be improved by a larger massive neutrino fraction as well. The ν -extended nonlocal model also prefers a higher value of H0 than Λ CDM , therefore in better agreement with local measurements. Our study provides one more example suggesting that the neutrino density fraction Ων is partially degenerated with the nature of the dark energy. This emphasizes the importance of cosmological and terrestrial neutrino research and, as a massive neutrino background impacts structure formation observables non-negligibly, proves to be especially relevant for future galaxy surveys.

  14. Specific targeting of TGF-β family ligands demonstrates distinct roles in the regulation of muscle mass in health and disease.

    PubMed

    Chen, Justin L; Walton, Kelly L; Hagg, Adam; Colgan, Timothy D; Johnson, Katharine; Qian, Hongwei; Gregorevic, Paul; Harrison, Craig A

    2017-06-27

    The transforming growth factor-β (TGF-β) network of ligands and intracellular signaling proteins is a subject of intense interest within the field of skeletal muscle biology. To define the relative contribution of endogenous TGF-β proteins to the negative regulation of muscle mass via their activation of the Smad2/3 signaling axis, we used local injection of adeno-associated viral vectors (AAVs) encoding ligand-specific antagonists into the tibialis anterior (TA) muscles of C57BL/6 mice. Eight weeks after AAV injection, inhibition of activin A and activin B signaling produced moderate (∼20%), but significant, increases in TA mass, indicating that endogenous activins repress muscle growth. Inhibiting myostatin induced a more profound increase in muscle mass (∼45%), demonstrating a more prominent role for this ligand as a negative regulator of adult muscle mass. Remarkably, codelivery of activin and myostatin inhibitors induced a synergistic response, resulting in muscle mass increasing by as much as 150%. Transcription and protein analysis indicated that this substantial hypertrophy was associated with both the complete inhibition of the Smad2/3 pathway and activation of the parallel bone morphogenetic protein (BMP)/Smad1/5 axis (recently identified as a positive regulator of muscle mass). Analyses indicated that hypertrophy was primarily driven by an increase in protein synthesis, but a reduction in ubiquitin-dependent protein degradation pathways was also observed. In models of muscular dystrophy and cancer cachexia, combined inhibition of activins and myostatin increased mass or prevented muscle wasting, respectively, highlighting the potential therapeutic advantages of specifically targeting multiple Smad2/3-activating ligands in skeletal muscle.

  15. Specific targeting of TGF-β family ligands demonstrates distinct roles in the regulation of muscle mass in health and disease

    PubMed Central

    Chen, Justin L.; Walton, Kelly L.; Hagg, Adam; Colgan, Timothy D.; Johnson, Katharine; Qian, Hongwei; Gregorevic, Paul; Harrison, Craig A.

    2017-01-01

    The transforming growth factor-β (TGF-β) network of ligands and intracellular signaling proteins is a subject of intense interest within the field of skeletal muscle biology. To define the relative contribution of endogenous TGF-β proteins to the negative regulation of muscle mass via their activation of the Smad2/3 signaling axis, we used local injection of adeno-associated viral vectors (AAVs) encoding ligand-specific antagonists into the tibialis anterior (TA) muscles of C57BL/6 mice. Eight weeks after AAV injection, inhibition of activin A and activin B signaling produced moderate (∼20%), but significant, increases in TA mass, indicating that endogenous activins repress muscle growth. Inhibiting myostatin induced a more profound increase in muscle mass (∼45%), demonstrating a more prominent role for this ligand as a negative regulator of adult muscle mass. Remarkably, codelivery of activin and myostatin inhibitors induced a synergistic response, resulting in muscle mass increasing by as much as 150%. Transcription and protein analysis indicated that this substantial hypertrophy was associated with both the complete inhibition of the Smad2/3 pathway and activation of the parallel bone morphogenetic protein (BMP)/Smad1/5 axis (recently identified as a positive regulator of muscle mass). Analyses indicated that hypertrophy was primarily driven by an increase in protein synthesis, but a reduction in ubiquitin-dependent protein degradation pathways was also observed. In models of muscular dystrophy and cancer cachexia, combined inhibition of activins and myostatin increased mass or prevented muscle wasting, respectively, highlighting the potential therapeutic advantages of specifically targeting multiple Smad2/3-activating ligands in skeletal muscle. PMID:28607086

  16. Associations of Low Muscle Mass and the Metabolic Syndrome in Caucasian and Asian Middle-aged and Older Adults.

    PubMed

    Scott, D; Park, M S; Kim, T N; Ryu, J Y; Hong, H C; Yoo, H J; Baik, S H; Jones, G; Choi, K M

    2016-03-01

    Age-related declines in skeletal muscle mass may confer significant metabolic consequences for older adults. Associations of low muscle mass and metabolic syndrome (MetS) in Caucasians, and comparisons with associations observed in Asian populations, have not been reported. We examined associations of low muscle mass and metabolic syndrome (MetS) in Asian and Caucasian middle-aged and older men and women using criteria for low muscle mass. Two population-based studies of Australian (Tasmanian Older Adult Cohort Study; TASOAC; N=1005) and Korean (Korean Sarcopenic Obesity Study; KSOS; N=376) community-dwelling adults, mean age 62 and 58 years, respectively. Appendicular lean mass (aLM) determined by dual-energy X-ray absorptiometry and normalised to height squared (aLM/Ht2), weight (aLM/Wt) or body mass index (aLM/BMI). Participants in the lowest sex-specific 20% for aLM measures were defined as having low muscle mass. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria. Although Australians demonstrated generally unfavourable anthropometric and metabolic characteristics compared to Koreans, prevalence of MetS was similar (29.5% in Australians and 31.4% in Koreans, respectively). Low aLM/Ht2 was associated with significantly reduced likelihood of MetS in both Australians (OR: 0.30, 95% CI 0.19 - 0.46) and Koreans (OR: 0.31, 95% CI 0.16 - 0.62). Conversely, low aLM/BMI was associated with increased odds for MetS in Australians (OR: 1.78, 95% CI 1.12 - 2.84), but not Koreans (OR: 1.33, 95% CI = 0.67 - 2.64). Low aLM/BMI is associated with significantly increased likelihood of MetS in Australian adults, but not Koreans, suggesting potential differences in effects of low muscle mass relative to body mass on cardiometabolic health in Caucasian and Asian middle-aged and older adults. Low muscle mass relative to height is associated with reduced likelihood of MetS in both populations.

  17. Ribosome abundance regulates the recovery of skeletal muscle protein mass upon recuperation from postnatal undernutrition in mice

    USDA-ARS?s Scientific Manuscript database

    Nutritionally-induced growth faltering in the perinatal period has been associated with reduced adult skeletal muscle mass; however, the mechanisms responsible for this are unclear. To identify the factors that determine the recuperative capacity of muscle mass, we studied offspring of FVB mouse dam...

  18. Acute inhibition of myostatin-family proteins preserves skeletal muscle in mouse models of cancer cachexia

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

    Benny Klimek, Margaret E.; Aydogdu, Tufan; Link, Majik J.

    2010-01-15

    Cachexia, progressive loss of fat and muscle mass despite adequate nutrition, is a devastating complication of cancer associated with poor quality of life and increased mortality. Myostatin is a potent tonic muscle growth inhibitor. We tested how myostatin inhibition might influence cancer cachexia using genetic and pharmacological approaches. First, hypermuscular myostatin null mice were injected with Lewis lung carcinoma or B16F10 melanoma cells. Myostatin null mice were more sensitive to tumor-induced cachexia, losing more absolute mass and proportionately more muscle mass than wild-type mice. Because myostatin null mice lack expression from development, however, we also sought to manipulate myostatin acutely.more » The histone deacetylase inhibitor Trichostatin A has been shown to increase muscle mass in normal and dystrophic mice by inducing the myostatin inhibitor, follistatin. Although Trichostatin A administration induced muscle growth in normal mice, it failed to preserve muscle in colon-26 cancer cachexia. Finally we sought to inhibit myostatin and related ligands by administration of the Activin receptor extracellular domain/Fc fusion protein, ACVR2B-Fc. Systemic administration of ACVR2B-Fc potently inhibited muscle wasting and protected adipose stores in both colon-26 and Lewis lung carcinoma cachexia, without affecting tumor growth. Enhanced cachexia in myostatin knockouts indicates that host-derived myostatin is not the sole mediator of muscle wasting in cancer. More importantly, skeletal muscle preservation with ACVR2B-Fc establishes that targeting myostatin-family ligands using ACVR2B-Fc or related molecules is an important and potent therapeutic avenue in cancer cachexia.« less

  19. Acute inhibition of myostatin-family proteins preserves skeletal muscle in mouse models of cancer cachexia.

    PubMed

    Benny Klimek, Margaret E; Aydogdu, Tufan; Link, Majik J; Pons, Marianne; Koniaris, Leonidas G; Zimmers, Teresa A

    2010-01-15

    Cachexia, progressive loss of fat and muscle mass despite adequate nutrition, is a devastating complication of cancer associated with poor quality of life and increased mortality. Myostatin is a potent tonic muscle growth inhibitor. We tested how myostatin inhibition might influence cancer cachexia using genetic and pharmacological approaches. First, hypermuscular myostatin null mice were injected with Lewis lung carcinoma or B16F10 melanoma cells. Myostatin null mice were more sensitive to tumor-induced cachexia, losing more absolute mass and proportionately more muscle mass than wild-type mice. Because myostatin null mice lack expression from development, however, we also sought to manipulate myostatin acutely. The histone deacetylase inhibitor Trichostatin A has been shown to increase muscle mass in normal and dystrophic mice by inducing the myostatin inhibitor, follistatin. Although Trichostatin A administration induced muscle growth in normal mice, it failed to preserve muscle in colon-26 cancer cachexia. Finally we sought to inhibit myostatin and related ligands by administration of the Activin receptor extracellular domain/Fc fusion protein, ACVR2B-Fc. Systemic administration of ACVR2B-Fc potently inhibited muscle wasting and protected adipose stores in both colon-26 and Lewis lung carcinoma cachexia, without affecting tumor growth. Enhanced cachexia in myostatin knockouts indicates that host-derived myostatin is not the sole mediator of muscle wasting in cancer. More importantly, skeletal muscle preservation with ACVR2B-Fc establishes that targeting myostatin-family ligands using ACVR2B-Fc or related molecules is an important and potent therapeutic avenue in cancer cachexia. Copyright 2009 Elsevier Inc. All rights reserved.

  20. Absolute dimensions and masses of eclipsing binaries. V. IQ Persei

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

    Lacy, C.H.; Frueh, M.L.

    1985-08-01

    New photometric and spectroscopic observations of the 1.7 day eclipsing binary IQ Persei (B8 + A6) have been analyzed to yield very accurate fundamental properties of the system. Reticon spectroscopic observations obtained at McDonald Observatory were used to determine accurate radial velocities of both stars in this slightly eccentric large light-ratio binary. A new set of VR light curves obtained at McDonald Observatory were analyzed by synthesis techniques, and previously published UBV light curves were reanalyzed to yield accurate photometric orbits. Orbital parameters derived from both sets of photometric observations are in excellent agreement. The absolute dimensions, masses, luminosities, andmore » apsidal motion period (140 yr) derived from these observations agree well with the predictions of theoretical stellar evolution models. The A6 secondary is still very close to the zero-age main sequence. The B8 primary is about one-third of the way through its main-sequence evolution. 27 references.« less

  1. A strategy for absolute proteome quantification with mass spectrometry by hierarchical use of peptide-concatenated standards.

    PubMed

    Kito, Keiji; Okada, Mitsuhiro; Ishibashi, Yuko; Okada, Satoshi; Ito, Takashi

    2016-05-01

    The accurate and precise absolute abundance of proteins can be determined using mass spectrometry by spiking the sample with stable isotope-labeled standards. In this study, we developed a strategy of hierarchical use of peptide-concatenated standards (PCSs) to quantify more proteins over a wider dynamic range. Multiple primary PCSs were used for quantification of many target proteins. Unique "ID-tag peptides" were introduced into individual primary PCSs, allowing us to monitor the exact amounts of individual PCSs using a "secondary PCS" in which all "ID-tag peptides" were concatenated. Furthermore, we varied the copy number of the "ID-tag peptide" in each PCS according to a range of expression levels of target proteins. This strategy accomplished absolute quantification over a wider range than that of the measured ratios. The quantified abundance of budding yeast proteins showed a high reproducibility for replicate analyses and similar copy numbers per cell for ribosomal proteins, demonstrating the accuracy and precision of this strategy. A comparison with the absolute abundance of transcripts clearly indicated different post-transcriptional regulation of expression for specific functional groups. Thus, the approach presented here is a faithful method for the absolute quantification of proteomes and provides insights into biological mechanisms, including the regulation of expressed protein abundance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The relationship of choline acetyltransferase activity at the neuromuscular junction to changes in muscle mass and function

    PubMed Central

    Diamond, Ivan; Franklin, Gary M.; Milfay, Dale

    1974-01-01

    1. The role of muscle mass and function in the regulation of choline acetyltransferase activity at the neuromuscular junction has been investigated in the rat. 2. Choline acetyltransferase (ChAc) is located in presynaptic nerve terminals and is a specific enzymatic marker of cholinergic innervation in muscle. 3. ChAc activity increased co-ordinately with developmental growth of the soleus muscle. However, another form of muscle growth, work hypertrophy, did not produce an increase in ChAc. 4. Growth arrest of muscle by hypophysectomy did not alter the normal development of ChAc activity, and cortisone-induced muscle atrophy did not reduce ChAc activity in the soleus or plantaris. 5. Tenotomy-induced muscle atrophy provoked a significant fall in ChAc in the soleus and plantaris. 6. The tonic soleus had significantly greater ChAc activity than the phasic plantaris. 7. These observations suggest that muscle mass per se does not influence the development and regulation of ChAc in muscle but that the quality of muscle contraction may modulate enzyme activity. PMID:4818500

  3. Type VI collagen turnover-related peptides-novel serological biomarkers of muscle mass and anabolic response to loading in young men.

    PubMed

    Nedergaard, Anders; Sun, Shu; Karsdal, Morten A; Henriksen, Kim; Kjær, Michael; Lou, Yunyun; He, Yi; Zheng, Qinlong; Suetta, Charlotte

    2013-12-01

    Immobilization-induced loss of muscle mass is a complex phenomenon with several parallels to sarcopenic and cachectic muscle loss. Muscle is a large organ with a protein turnover that is orders of magnitude larger than most other tissues. Thus, we hypothesize that muscle loss and regain is reflected by peptide biomarkers derived from type VI collagen processing released in the circulation. In order to test this hypothesis, we set out to develop an ELISA assay against an type VI collagen N-terminal globular domain epitope (IC6) and measured the levels of IC6 and an MMP-generated degradation fragment of collagen 6, (C6M) in a human immobilization-remobilization study setup with young (n = 11) and old (n = 9) men. They were subjected to 2 weeks of unilateral lower limb immobilization followed by 4 weeks of remobilization including thrice weekly resistance training, using the contralateral leg as internal controls. Subjects were sampled for strength, quadriceps muscle volume and blood at baseline (PRE), post-immobilization (2W), and post-remobilization (4W). Blood were subsequently analyzed for levels of the C6M and IC6 biomarkers. We subsequently tested if there was any correlation between C6M, IC6, or the C6M/IC6 ratio and muscle mass or strength at baseline. We also tested whether there was any relation between these biomarkers and changes in muscle mass or strength with immobilization or remobilization. The model produced significant loss of muscle mass and strength in the immobilized leg. This loss was bigger in young subjects than in elderly, but whereas the young recovered almost fully, the elderly had limited regrowth of muscle. We found a significant correlation between IC6 and muscle mass at baseline in young subjects (R (2) = 0.6563, p = 0.0045), but none in the elderly. We also found a significant correlation between C6M measured at the 4W time point and the change in muscle mass during remobilization, again only manifesting in the young

  4. Phenotype selection reveals coevolution of muscle glycogen and protein and PTEN as a gate keeper for the accretion of muscle mass in adult female mice.

    PubMed

    Sawitzky, Mandy; Zeissler, Anja; Langhammer, Martina; Bielohuby, Maximilian; Stock, Peggy; Hammon, Harald M; Görs, Solvig; Metges, Cornelia C; Stoehr, Barbara J M; Bidlingmaier, Martin; Fromm-Dornieden, Carolin; Baumgartner, Bernhard G; Christ, Bruno; Brenig, Bertram; Binder, Gerhard; Metzger, Friedrich; Renne, Ulla; Hoeflich, Andreas

    2012-01-01

    We have investigated molecular mechanisms for muscle mass accretion in a non-inbred mouse model (DU6P mice) characterized by extreme muscle mass. This extreme muscle mass was developed during 138 generations of phenotype selection for high protein content. Due to the repeated trait selection a complex setting of different mechanisms was expected to be enriched during the selection experiment. In muscle from 29-week female DU6P mice we have identified robust increases of protein kinase B activation (AKT, Ser-473, up to 2-fold) if compared to 11- and 54-week DU6P mice or controls. While a number of accepted effectors of AKT activation, including IGF-I, IGF-II, insulin/IGF-receptor, myostatin or integrin-linked kinase (ILK), were not correlated with this increase, phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was down-regulated in 29-week female DU6P mice. In addition, higher levels of PTEN phosphorylation were found identifying a second mechanism of PTEN inhibition. Inhibition of PTEN and activation of AKT correlated with specific activation of p70S6 kinase and ribosomal protein S6, reduced phosphorylation of eukaryotic initiation factor 2α (eIF2α) and higher rates of protein synthesis in 29-week female DU6P mice. On the other hand, AKT activation also translated into specific inactivation of glycogen synthase kinase 3ß (GSK3ß) and an increase of muscular glycogen. In muscles from 29-week female DU6P mice a significant increase of protein/DNA was identified, which was not due to a reduction of protein breakdown or to specific increases of translation initiation. Instead our data support the conclusion that a higher rate of protein translation is contributing to the higher muscle mass in mid-aged female DU6P mice. Our results further reveal coevolution of high protein and high glycogen content during the selection experiment and identify PTEN as gate keeper for muscle mass in mid-aged female DU6P mice.

  5. Phenotype Selection Reveals Coevolution of Muscle Glycogen and Protein and PTEN as a Gate Keeper for the Accretion of Muscle Mass in Adult Female Mice

    PubMed Central

    Sawitzky, Mandy; Zeissler, Anja; Langhammer, Martina; Bielohuby, Maximilian; Stock, Peggy; Hammon, Harald M.; Görs, Solvig; Metges, Cornelia C.; Stoehr, Barbara J. M.; Bidlingmaier, Martin; Fromm-Dornieden, Carolin; Baumgartner, Bernhard G.; Christ, Bruno; Brenig, Bertram; Binder, Gerhard; Metzger, Friedrich; Renne, Ulla; Hoeflich, Andreas

    2012-01-01

    We have investigated molecular mechanisms for muscle mass accretion in a non-inbred mouse model (DU6P mice) characterized by extreme muscle mass. This extreme muscle mass was developed during 138 generations of phenotype selection for high protein content. Due to the repeated trait selection a complex setting of different mechanisms was expected to be enriched during the selection experiment. In muscle from 29-week female DU6P mice we have identified robust increases of protein kinase B activation (AKT, Ser-473, up to 2-fold) if compared to 11- and 54-week DU6P mice or controls. While a number of accepted effectors of AKT activation, including IGF-I, IGF-II, insulin/IGF-receptor, myostatin or integrin-linked kinase (ILK), were not correlated with this increase, phosphatase and tensin homologue deleted on chromosome 10 (PTEN) was down-regulated in 29-week female DU6P mice. In addition, higher levels of PTEN phosphorylation were found identifying a second mechanism of PTEN inhibition. Inhibition of PTEN and activation of AKT correlated with specific activation of p70S6 kinase and ribosomal protein S6, reduced phosphorylation of eukaryotic initiation factor 2α (eIF2α) and higher rates of protein synthesis in 29-week female DU6P mice. On the other hand, AKT activation also translated into specific inactivation of glycogen synthase kinase 3ß (GSK3ß) and an increase of muscular glycogen. In muscles from 29-week female DU6P mice a significant increase of protein/DNA was identified, which was not due to a reduction of protein breakdown or to specific increases of translation initiation. Instead our data support the conclusion that a higher rate of protein translation is contributing to the higher muscle mass in mid-aged female DU6P mice. Our results further reveal coevolution of high protein and high glycogen content during the selection experiment and identify PTEN as gate keeper for muscle mass in mid-aged female DU6P mice. PMID:22768110

  6. Dietary Protein Intake and Lean Muscle Mass in Survivors of Childhood Acute Lymphoblastic Leukemia: Report From the St. Jude Lifetime Cohort Study.

    PubMed

    Boland, Alexandra M; Gibson, Todd M; Lu, Lu; Kaste, Sue C; DeLany, James P; Partin, Robyn E; Lanctot, Jennifer Q; Howell, Carrie R; Nelson, Heather H; Chemaitilly, Wassim; Pui, Ching-Hon; Robison, Leslie L; Mulrooney, Daniel A; Hudson, Melissa M; Ness, Kirsten K

    2016-07-01

    Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for low lean muscle mass and muscle weakness, which may contribute to inactivity and early development of chronic diseases typically seen in older adults. Although increasing protein intake, in combination with resistance training, improves lean muscle mass in other populations, it is not known whether muscular tissue among survivors of ALL, whose impairments are treatment-related, will respond similarly. The aim of this study was to evaluate associations among dietary protein intake, resistance training, and lean muscle mass in survivors of ALL and age-, sex-, and race-matched controls. This was a cross-sectional study. Lean muscle mass was determined with dual-energy x-ray absorptiometry, dietary information with 24-hour recalls, and participation in resistance training with a questionnaire. Participants were 365 survivors of ALL (52% male; 87% white; median age=28.5 years, range=23.6-31.7) and 365 controls with no previous cancer. Compared with controls, survivors of ALL had lower lean muscle mass (55.0 versus 57.2 kg, respectively) and lower percentage of lean muscle mass (68.6% versus 71.4%, respectively) than controls. Similar proportions of survivors (71.1%) and controls (69.7%) met recommended dietary protein intake (0.8 g/kg/d). Survivors (45.4%) were less likely to report resistance training than controls (53.8%). In adjusted models, 1-g higher protein intake per kilogram of body mass per day was associated with a 7.9% increase and resistance training ≥1×wk, with a 2.8% increase in lean muscle mass. The cross-sectional study design limits temporal evaluation of the association between protein intake and lean muscle mass. The findings suggest that survivors of childhood ALL with low lean muscle mass may benefit from optimizing dietary protein intake in combination with resistance training. Research is needed to determine whether resistance training with protein supplementation

  7. Dietary Protein Intake and Lean Muscle Mass in Survivors of Childhood Acute Lymphoblastic Leukemia: Report From the St. Jude Lifetime Cohort Study

    PubMed Central

    Boland, Alexandra M.; Gibson, Todd M.; Lu, Lu; Kaste, Sue C.; DeLany, James P.; Partin, Robyn E.; Lanctot, Jennifer Q.; Howell, Carrie R.; Nelson, Heather H.; Chemaitilly, Wassim; Pui, Ching-Hon; Robison, Leslie L.; Mulrooney, Daniel A.; Hudson, Melissa M.

    2016-01-01

    Background Survivors of childhood acute lymphoblastic leukemia (ALL) are at risk for low lean muscle mass and muscle weakness, which may contribute to inactivity and early development of chronic diseases typically seen in older adults. Although increasing protein intake, in combination with resistance training, improves lean muscle mass in other populations, it is not known whether muscular tissue among survivors of ALL, whose impairments are treatment-related, will respond similarly. Objective The aim of this study was to evaluate associations among dietary protein intake, resistance training, and lean muscle mass in survivors of ALL and age-, sex-, and race-matched controls. Design This was a cross-sectional study. Methods Lean muscle mass was determined with dual-energy x-ray absorptiometry, dietary information with 24-hour recalls, and participation in resistance training with a questionnaire. Participants were 365 survivors of ALL (52% male; 87% white; median age=28.5 years, range=23.6–31.7) and 365 controls with no previous cancer. Results Compared with controls, survivors of ALL had lower lean muscle mass (55.0 versus 57.2 kg, respectively) and lower percentage of lean muscle mass (68.6% versus 71.4%, respectively) than controls. Similar proportions of survivors (71.1%) and controls (69.7%) met recommended dietary protein intake (0.8 g/kg/d). Survivors (45.4%) were less likely to report resistance training than controls (53.8%). In adjusted models, 1-g higher protein intake per kilogram of body mass per day was associated with a 7.9% increase and resistance training ≥1×wk, with a 2.8% increase in lean muscle mass. Limitations The cross-sectional study design limits temporal evaluation of the association between protein intake and lean muscle mass. Conclusions The findings suggest that survivors of childhood ALL with low lean muscle mass may benefit from optimizing dietary protein intake in combination with resistance training. Research is needed to

  8. Does Skeletal Muscle Mass Influence Breast Cancer? Evaluating Mammary Tumorigenesis and Progression Genetically Hyper-Muscular Mice

    DTIC Science & Technology

    2006-07-01

    the skeletal muscle-specific muscle growth inhibitor myostatin and mice expressing a dominant negative form of the myostatin receptor, Activin...and rates of breast cancer initiation and progression. 15. SUBJECT TERMS Breast cancer, skeletal muscle, myostatin , MPA, DMBA, Activin receptor 16...including interleukins, Insulin-like Growth Factor (IGF) isoforms, IGF-binding proteins and myostatin . To determine the effect of skeletal muscle mass

  9. Blockade of Metallothioneins 1 and 2 Increases Skeletal Muscle Mass and Strength

    PubMed Central

    Summermatter, Serge; Bouzan, Anais; Pierrel, Eliane; Melly, Stefan; Stauffer, Daniela; Gutzwiller, Sabine; Nolin, Erin; Dornelas, Christina; Fryer, Christy; Leighton-Davies, Juliet; Glass, David J.

    2016-01-01

    ABSTRACT Metallothioneins are proteins that are involved in intracellular zinc storage and transport. Their expression levels have been reported to be elevated in several settings of skeletal muscle atrophy. We therefore investigated the effect of metallothionein blockade on skeletal muscle anabolism in vitro and in vivo. We found that concomitant abrogation of metallothioneins 1 and 2 results in activation of the Akt pathway and increases in myotube size, in type IIb fiber hypertrophy, and ultimately in muscle strength. Importantly, the beneficial effects of metallothionein blockade on muscle mass and function was also observed in the setting of glucocorticoid addition, which is a strong atrophy-inducing stimulus. Given the blockade of atrophy and the preservation of strength in atrophy-inducing settings, these results suggest that blockade of metallothioneins 1 and 2 constitutes a promising approach for the treatment of conditions which result in muscle atrophy. PMID:27956698

  10. A novel double-focusing time-of-flight mass spectrometer for absolute recoil ion cross sections measurements

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

    Sigaud, L., E-mail: lsigaud@if.uff.br; Jesus, V. L. B. de; Ferreira, Natalia

    In this work, the inclusion of an Einzel-like lens inside the time-of-flight drift tube of a standard mass spectrometer coupled to a gas cell—to study ionization of atoms and molecules by electron impact—is described. Both this lens and a conical collimator are responsible for further focalization of the ions and charged molecular fragments inside the spectrometer, allowing a much better resolution at the time-of-flight spectra, leading to a separation of a single mass-to-charge unit up to 100 a.m.u. The procedure to obtain the overall absolute efficiency of the spectrometer and micro-channel plate detector is also discussed.

  11. A novel double-focusing time-of-flight mass spectrometer for absolute recoil ion cross sections measurements.

    PubMed

    Sigaud, L; de Jesus, V L B; Ferreira, Natalia; Montenegro, E C

    2016-08-01

    In this work, the inclusion of an Einzel-like lens inside the time-of-flight drift tube of a standard mass spectrometer coupled to a gas cell-to study ionization of atoms and molecules by electron impact-is described. Both this lens and a conical collimator are responsible for further focalization of the ions and charged molecular fragments inside the spectrometer, allowing a much better resolution at the time-of-flight spectra, leading to a separation of a single mass-to-charge unit up to 100 a.m.u. The procedure to obtain the overall absolute efficiency of the spectrometer and micro-channel plate detector is also discussed.

  12. Insulin Treatment Attenuates Decline of Muscle Mass in Japanese Patients with Type 2 Diabetes.

    PubMed

    Bouchi, Ryotaro; Fukuda, Tatsuya; Takeuchi, Takato; Nakano, Yujiro; Murakami, Masanori; Minami, Isao; Izumiyama, Hajime; Hashimoto, Koshi; Yoshimoto, Takanobu; Ogawa, Yoshihiro

    2017-07-01

    Sarcopenia is defined as an age-related loss of skeletal muscle mass and strength, and is a major cause of disability and mobility limitations. Recent studies have demonstrated that type 2 diabetes and insulin signaling deficiencies contribute to the progression of sarcopenia, suggesting that a sufficient supply of insulin to the skeletal muscles may be important for the maintenance of muscle function; however, little has been reported regarding whether insulin treatment can protect against sarcopenia. We conducted a retrospective observational study to examine the impact of insulin treatment on the muscle mass of patients with type 2 diabetes. A total of 312 patients (mean age: 64 ± 11 years; 40.8% female; 27.6% treated with insulin) were studied in this retrospective observational study. Skeletal muscle index (SMI) and grip strength (kg) were used to assess sarcopenia. The prevalence of sarcopenia was 18.0%. Insulin treatment was shown to be protective against the annual decline of SMI (standardized β 0.195; p = 0.025) even after adjusting for covariates, including age, gender, duration of diabetes, and body mass index. In a cohort matched by propensity scores, insulin treatment significantly increased the 1-year change in SMI (mean ± SE) compared with non-insulin-treated group (2.40 ± 0.98% vs. -0.43 ± 0.98%; p = 0.050). Our data suggest that insulin treatment could attenuate the progression of sarcopenia in patients with type 2 diabetes.

  13. Absolute Properties of the Pulsating Post-mass Transfer Eclipsing Binary OO Draconis

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho

    2018-01-01

    OO Dra is a short-period Algol system with a δ Sct-like pulsator. We obtained time-series spectra between 2016 February and May to derive the fundamental parameters of the binary star and to study its evolutionary scenario. The radial velocity (RV) curves for both components were presented, and the effective temperature of the hotter and more massive primary was determined to be {T}{eff,1}=8260+/- 210 K by comparing the disentangling spectrum and the Kurucz models. Our RV measurements were solved with the BV light curves of Zhang et al. using the Wilson-Devinney binary code. The absolute dimensions of each component are determined as follows: M 1 = 2.03 ± 0.06 {M}⊙ , M 2 = 0.19 ± 0.01 {M}⊙ , R 1 = 2.08 ± 0.03 {R}⊙ , R 2 = 1.20 ± 0.02 {R}⊙ , L 1 = 18 ± 2 {L}⊙ , and L 2 = 2.0 ± 0.2 {L}⊙ . Comparison with stellar evolution models indicated that the primary star resides inside the δ Sct instability strip on the main sequence, while the cool secondary component is noticeably overluminous and oversized. We demonstrated that OO Dra is an oscillating post-mass transfer R CMa-type binary; the originally more massive star became the low-mass secondary component through mass loss caused by stellar wind and mass transfer, and the gainer became the pulsating primary as the result of mass accretion. The R CMa stars, such as OO Dra, are thought to have formed by non-conservative binary evolution and ultimately to evolve into EL CVn stars.

  14. Strong thermal leptogenesis and the absolute neutrino mass scale

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

    Bari, Pasquale Di; King, Sophie E.; Fiorentin, Michele Re, E-mail: pdb1d08@soton.ac.uk, E-mail: sk1806@soton.ac.uk, E-mail: m.re-fiorentin@soton.ac.uk

    We show that successful strong thermal leptogenesis, where the final asymmetry is independent of the initial conditions and in particular a large pre-existing asymmetry is efficiently washed-out, favours values of the lightest neutrino mass m{sub 1}∼>10 meV for normal ordering (NO) and m{sub 1}∼>3 meV for inverted ordering (IO) for models with orthogonal matrix entries respecting |Ω{sub ij}{sup 2}|∼<2. We show analytically why lower values of m{sub 1} require a higher level of fine tuning in the seesaw formula and/or in the flavoured decay parameters (in the electronic for NO, in the muonic for IO). We also show how this constraint existsmore » thanks to the measured values of the neutrino mixing angles and could be tightened by a future determination of the Dirac phase. Our analysis also allows us to place a more stringent constraint for a specific model or class of models, such as SO(10)-inspired models, and shows that some models cannot realise strong thermal leptogenesis for any value of m{sub 1}. A scatter plot analysis fully supports the analytical results. We also briefly discuss the interplay with absolute neutrino mass scale experiments concluding that they will be able in the coming years to either corner strong thermal leptogenesis or find positive signals pointing to a non-vanishing m{sub 1}. Since the constraint is much stronger for NO than for IO, it is very important that new data from planned neutrino oscillation experiments will be able to solve the ambiguity.« less

  15. The association of low muscle mass with soluble receptor for advanced glycation end products (sRAGE): The Korean Sarcopenic Obesity Study (KSOS).

    PubMed

    Kim, Tae Nyun; Park, Man Sik; Lee, Eun Joo; Chung, Hye Soo; Yoo, Hye Jin; Kang, Hyun Joo; Song, Wook; Baik, Sei Hyun; Choi, Kyung Mook

    2018-03-01

    Advanced glycation end products (AGEs) are accumulated with aging in various tissues of humans. The soluble receptor for AGEs (sRAGE) exerts a protective role against the development of aging-related chronic disorders by neutralizing the action of AGEs. We investigated the implication of sRAGE on low muscle mass in Asian men and women. This cross-sectional study included a 390-participant, nondiabetic subcohort recruited within the framework of the Korean Sarcopenic Obesity Study, an ongoing prospective cohort study. Low muscle mass was defined based on the distribution of appendicular skeletal muscle mass divided by body mass index, as proposed by the Foundation for the National Institutes Sarcopenia Project. Serum sRAGE levels were significantly lower in participants with low muscle mass than in participants without low muscle mass (0.76 [0.60-1.00] ng/mL vs 0.87 [0.67-1.15] ng/mL, P = .005). In age- and sex-adjusted correlation analyses, appendicular skeletal muscle mass divided by body mass index was associated with sRAGE (r = 0.109, P = .037). Furthermore, decreased circulating levels of sRAGE are independently associated with low muscle mass (odds ratio = 0.254, P = .002) after adjusting for confounding factors, including insulin resistance and inflammatory markers. The present study shows that a low circulating level of sRAGE may be an independent risk factor for the presence of low muscle mass. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Muscle Mass Loss Is a Potential Predictor of 90-Day Mortality in Older Adults with Aspiration Pneumonia.

    PubMed

    Maeda, Keisuke; Akagi, Junji

    2017-01-01

    To investigate the association between loss of muscle mass and aspiration pneumonia (AP). Prospective observational cohort. Acute geriatric hospital. Individuals admitted to the hospital for AP (N = 151; mean age 85.9; 49.7% male). Appendicular skeletal muscle index (ASMI; appendicular skeletal muscle mass divided by height squared) was used to evaluate muscle mass. Data on age, sex, body mass index, Mini Nutritional Assessment-Short Form score, Barthel Index score, Charlson Comorbidity Index score, and pneumonia severity (Japanese version of the CURB-65 (C (confusion), U (blood urea nitrogen ≥20 mg/dL), R (respiratory rate ≥30 breaths/min), B (systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg), 65 (aged ≥65) severity score (A-DROP)) were obtained. Outcomes included 30- and 90-day mortality. Mild, moderate, severe, and extremely severe AP were observed in 1.3%, 70.2%, 25.8%, and 2.6% of participants, respectively. On Kaplan-Meier analysis, participants in the lowest ASMI quartile for each sex were more likely to die than those in the other quartiles (log-lank test P = .005). Multivariate logistic analyses showed that ASMI and A-DROP were independent predictors of 90-day mortality; only A-DROP was a significant predictor of 30-day mortality (P < .001). Cox regression analysis also showed that the first ASMI quartile was independently associated with mortality (hazard ratio = 2.19; 95% confidence interval = 1.06-4.52; P = .03). Low muscle mass is a potential predictor of long-term mortality in individuals with AP. Prospectively preventing muscle mass deterioration may be beneficial for recovery from AP in older adults. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  17. Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders.

    PubMed

    Lemon, P W; Tarnopolsky, M A; MacDougall, J D; Atkinson, S A

    1992-08-01

    This randomized double-blind cross-over study assessed protein (PRO) requirements during the early stages of intensive bodybuilding training and determined whether supplemental PRO intake (PROIN) enhanced muscle mass/strength gains. Twelve men [22.4 +/- 2.4 (SD) yr] received an isoenergetic PRO (total PROIN 2.62 g.kg-1.day-1) or carbohydrate (CHO; total PROIN 1.35 g.kg-1.day-1) supplement for 1 mo each during intensive (1.5 h/day, 6 days/wk) weight training. On the basis of 3-day nitrogen balance (NBAL) measurements after 3.5 wk on each treatment (8.9 +/- 4.2 and -3.4 +/- 1.9 g N/day, respectively), the PROIN necessary for zero NBAL (requirement) was 1.4-1.5 g.kg-1.day-1. The recommended intake (requirement + 2 SD) was 1.6-1.7 g.kg-1.day-1. However, strength (voluntary and electrically evoked) and muscle mass [density, creatinine excretion, muscle area (computer axial tomography scan), and biceps N content] gains were not different between diet treatments. These data indicate that, during the early stages of intensive bodybuilding training, PRO needs are approximately 100% greater than current recommendations but that PROIN increases from 1.35 to 2.62 g.kg-1.day-1 do not enhance muscle mass/strength gains, at least during the 1st mo of training. Whether differential gains would occur with longer training remains to be determined.

  18. Healthy community-living older men differ from women in associations between myostatin levels and skeletal muscle mass.

    PubMed

    Peng, Li-Ning; Lee, Wei-Ju; Liu, Li-Kuo; Lin, Ming-Hsien; Chen, Liang-Kung

    2018-04-13

    Myostatin is a negative regulator of muscle growth but the relationship between serum myostatin levels and muscle mass is unclear. This study investigated the association between serum myostatin levels and skeletal muscle mass among healthy older community residents in Taiwan, to evaluate the potential of serum myostatin as a biomarker for diagnosing sarcopenia and/or evaluating the effect of its treatment. Study data were excerpted from a random subsample of the I-Lan Longitudinal Aging Study population. Serum myostatin levels were determined and categorized into tertiles (low, medium, high). Relative appendicular skeletal muscle mass (RASM) was calculated as appendicular lean body mass by dual-energy X-ray absorptiometry divided by height squared (kg/m 2 ). Low muscle mass was defined as recommended by the Asian Working Group for Sarcopenia. The analytic study sample comprised 463 adults (mean age: 69.1 years; 49.5% men). Compared with subjects with normal RASM, those with lower RASM were older and frailer, with significantly higher prevalence of malnutrition, lower serum dehydroepiandrosterone (DHEA) levels, and were more likely to have low serum myostatin status. Multivariable logistic regression analysis showed that male sex (OR 3.60, 95% CI 1.30-9.92), malnutrition (OR 4.39, 95% CI 1.56-12.36), DHEA (OR 0.99, 95% CI 0.99-1.00), and low myostatin (OR 3.23, 95% CI 1.49-7.01) were all independent risk factors for low RASM (all P < 0.05). In men, DHEA (OR 0.99, 95% CI 0.98-1.00) and low myostatin (OR 4.89, 95% CI 1.79-13.37) were significantly associated with low RASM (both P < 0.05); however, only malnutrition was associated with low RASM in women (OR 13.59, 95% CI 2.22-83.25, P < 0.05). Among healthy community-living older adults, low serum myostatin levels were associated with low skeletal muscle mass in men, but not in women. Our results do not support using serum myostatin levels to diagnose sarcopenia, or to monitor how it responds to treatments

  19. Correlates of increased lean muscle mass in women with polycystic ovary syndrome.

    PubMed

    Carmina, E; Guastella, E; Longo, R A; Rini, G B; Lobo, R A

    2009-10-01

    Muscle mass plays an important role in determining cardiovascular and metabolic risks in polycystic ovary syndrome (PCOS). In addition, whether lean mass influences carotid intima-media thickness (IMT) in PCOS has not been assessed. Prospective investigation. Ninety-five women with PCOS were age- and weight-matched to 90 ovulatory controls. All women had dual X-ray absorptiometry for lean, fat and bone mass, and bone mass density (BMD). Serum testosterone, sex hormone-binding globulin, insulin, and glucose and carotid IMT were determined. Free androgen index (FAI) and insulin resistance (by QUICKI) were calculated. In PCOS, waist circumference and insulin were higher and QUICKI lower than in controls (P<0.01). Trunk fat mass, % trunk fat, and lean mass were higher in PCOS compared to controls (P<0.01), while total bone mass and BMD were similar. IMT was increased in PCOS (P<0.01) but only 15% of PCOS patients had abnormal (> or = 0.9 mm) values. Lean mass correlated with fat parameters, insulin, QUICKI, and FAI, but not with total testosterone; and after adjustments for insulin and QUICKI, lean mass still correlated with fat mass (P<0.01) but not FAI. Lean mass correlated with IMT (P<0.01), but this was dependent on insulin. However, excluding those patients with abnormal IMT values, IMT correlated with lean mass independently of insulin. Bone mass correlated with lean and fat mass, but not with insulin or androgen. PCOS patients with 'pathological' IMT values had higher % trunk fat, lean mass, and insulin, lower QUICKI, and higher testosterone and FAI compared with those with normal IMT. Lean mass is increased in PCOS, while bone mass is similar to that of matched controls. The major correlates of lean mass are fat mass and insulin but not androgen. Lean mass also correlated with IMT, and although influenced by insulin, small changes in IMT may partially reflect changes in muscle mass, while clearly abnormal values relate to more severe abnormalities of PCOS.

  20. Resistance Exercise Impacts Lean Muscle Mass in Women with Polycystic Ovary Syndrome.

    PubMed

    Kogure, Gislaine Satyko; Miranda-Furtado, Cristiana Libardi; Silva, Rafael Costa; Melo, Anderson Sanches; Ferriani, Rui Alberto; De Sá, Marcos Felipe Silva; Dos Reis, Rosana Maria

    2016-04-01

    This study investigated the effects of progressive resistance training (PRT) on lean muscle mass (LMM) in women with or without polycystic ovary syndrome (PCOS) and its effects on metabolic factors and concentrations of related steroid hormones. This was a nonrandomized, therapeutic, open, single-arm study. All in all, 45 sedentary women with PCOS and 52 without (non-PCOS), 18-37 yr of age, with body mass indexes (BMI) of 18-39.9 kg·m(-2) of all races and social status, performed PRT three times a week for 4 months. Before and after PRT, the concentrations of hormones and metabolic factors and waist circumference were measured. LMM and total body fat percentage were determined using dual-energy x-ray absorptiometry. Clinical characteristics, LMM, and fasting glucose were adjusted for confounding covariables and compared using general linear mixed models. Each patient's menstrual history was taken before study enrollment and after PRT. PRT resulted in reduced plasma testosterone and fasting glucose levels. After PRT, the androstenedione concentration increased and the sex hormone-binding globulin concentration decreased in women with PCOS. The waist circumference was reduced (P < 0.01) and the muscle mass index, lean mass (LM)/height2, increased in women with PCOS (P = 0.04). Women with PCOS showed increased muscle mass indexes of appendicular LM/height2 (P = 0.03) and LM/height2 (P < 0.01) compared with the baseline. Total LM and trunk LM were elevated in women with PCOS (P = 0.01) at the baseline and after PRT. To our knowledge, this is the first report to show that resistance exercise alone can improve hyperandrogenism, reproductive function, and body composition by decreasing visceral fat and increasing LMM, but it has no metabolic impact on women with PCOS.

  1. Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study.

    PubMed

    Sénéchal, Martin; Johannsen, Neil M; Swift, Damon L; Earnest, Conrad P; Lavie, Carl J; Blair, Steven N; Church, Timothy S

    2015-01-01

    Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM. A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs). Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05). The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement. Clinicaltrials.gov NCT00458133.

  2. Association between Changes in Muscle Quality with Exercise Training and Changes in Cardiorespiratory Fitness Measures in Individuals with Type 2 Diabetes Mellitus: Results from the HART-D Study

    PubMed Central

    Sénéchal, Martin; Johannsen, Neil M.; Swift, Damon L.; Earnest, Conrad P.; Lavie, Carl J.; Blair, Steven N.; Church, Timothy S.

    2015-01-01

    Introduction Type 2 diabetes mellitus (T2DM) is associated with a reduction in muscle quality. However, there is inadequate empirical evidence to determine whether changes in muscle quality following exercise are associated with improvement in cardiorespiratory fitness (CRF) in individuals with T2DM. The objective of this study was to investigate the association between change in muscle quality following a 9-month intervention of aerobic training (AT), resistance training (RT) or a combination of both (ATRT) and cardiorespiratory fitness (CRF) in individuals with T2DM. Material and Methods A total of 196 participants were randomly assigned to a control, AT, RT, or combined ATRT for a 9-months intervention. The exposure variable was change in muscle quality [(Post: leg muscle strength/leg muscle mass)-[(Pre: leg muscle strength/leg muscle mass)]. Dependent variables were change in CRF measures including absolute and relative VO2peak, and treadmill time to exhaustion (TTE) and estimated metabolic equivalent task (METs). Results Continuous change in muscle quality was independently associated with change in absolute (β = 0.015; p = 0.019) and relative (β = 0.200; p = 0.005) VO2peak, and TTE (β = 0.170; p = 0.043), but not with estimated METs (p > 0.05). A significant trend was observed across tertiles of change in muscle quality for changes in absolute (β = 0.050; p = 0.005) and relative (β = 0.624; p = 0.002) VO2peak following 9 months of exercise training. No such association was observed for change in TTE and estimated METs (p > 0.05). Discussion The results from this ancillary study suggest that change in muscle quality following exercise training is associated with a greater improvement in CRF in individuals with T2DM. Given the effect RT has on increasing muscle quality, especially as part of a recommended training program (ATRT), individuals with T2DM should incorporate RT into their AT regimens to optimize CRF improvement. Trial Registration

  3. Muscle Contractile Properties in Severely Burned Rats

    PubMed Central

    Wu, Xiaowu; Wolf, Steven E.; Walters, Thomas J.

    2010-01-01

    Burn induces a sustained catabolic response which causes massive loss of muscle mass after injury. A better understanding of the dynamics of muscle wasting and its impact on muscle function is necessary for the development of effective treatments. Male Sprague-Dawley rats underwent either a 40% total body surface area (TBSA) scald burn or sham burn, and were further assigned to subgroups at four time points after injury (days 3, 7, 14 and 21). In situ isometric contractile properties were measured including twitch tension (Pt), tetanic tension (Po) and fatigue properties. Body weight decreased in burn and sham groups through day 3, however, body weight in the sham groups recovered and increased over time compared to burned groups, which progressively decreased until day 21 after injury. Significant differences in muscle wet weight and protein weight were found between sham and burn. Significant differences in muscle contractile properties were found at day 14 with lower absolute Po as well as specific Po in burned rats compared to sham. After burn, the muscle twitch tension was significantly higher than the sham at day 21. No significant difference in fatigue properties was found between the groups. This study demonstrates dynamics of muscle atrophy and muscle contractile properties after severe burn; this understanding will aid in the development of approaches designed to reduce the rate and extent of burn induced muscle loss and function. PMID:20381255

  4. The role of MicroRNAs in COPD muscle dysfunction and mass loss: implications on the clinic.

    PubMed

    Barreiro, Esther

    2016-09-01

    Chronic obstructive pulmonary disease (COPD) is a common preventable and treatable disease and a leading cause of morbidity and mortality worldwide. In COPD, comorbidities, acute exacerbations, and systemic manifestations negatively influence disease severity, prognosis, and progression regardless of the respiratory condition. Several factors and biological mechanisms are involved in the pathophysiology of COPD muscle dysfunction. The non-coding microRNAs were shown to be differentially expressed in the respiratory and limb muscles of patients with COPD. Moreover, a differential expression profile of muscle-specific microRNAs has also been demonstrated in the lower limb muscles of COPD patients with and without muscle mass loss and weakness. All these features are reviewed herein. The most relevant articles on the topic in question were selected from PubMed to write this review. Expert commentary: MicroRNAs are excellent targets for the design of specific therapeutic interventions in patients with muscle weakness. Selective enhancers of microRNAs that promote myogenesis (proliferation and differentiation of satellite cells) should be designed to alleviate the negative impact of skeletal muscle dysfunction and mass loss in COPD regardless of the degree of the airway obstruction.

  5. The role of mTOR signaling in the regulation of protein synthesis and muscle mass during immobilization in mice

    PubMed Central

    You, Jae-Sung; Anderson, Garrett B.; Dooley, Matthew S.; Hornberger, Troy A.

    2015-01-01

    ABSTRACT The maintenance of skeletal muscle mass contributes substantially to health and to issues associated with the quality of life. It has been well recognized that skeletal muscle mass is regulated by mechanically induced changes in protein synthesis, and that signaling by mTOR is necessary for an increase in protein synthesis and the hypertrophy that occurs in response to increased mechanical loading. However, the role of mTOR signaling in the regulation of protein synthesis and muscle mass during decreased mechanical loading remains largely undefined. In order to define the role of mTOR signaling, we employed a mouse model of hindlimb immobilization along with pharmacological, mechanical and genetic means to modulate mTOR signaling. The results first showed that immobilization induced a decrease in the global rates of protein synthesis and muscle mass. Interestingly, immobilization also induced an increase in mTOR signaling, eIF4F complex formation and cap-dependent translation. Blocking mTOR signaling during immobilization with rapamycin not only impaired the increase in eIF4F complex formation, but also augmented the decreases in global protein synthesis and muscle mass. On the other hand, stimulating immobilized muscles with isometric contractions enhanced mTOR signaling and rescued the immobilization-induced decrease in global protein synthesis through a rapamycin-sensitive mechanism that was independent of ribosome biogenesis. Unexpectedly, the effects of isometric contractions were also independent of eIF4F complex formation. Similar to isometric contractions, overexpression of Rheb in immobilized muscles enhanced mTOR signaling, cap-dependent translation and global protein synthesis, and prevented the reduction in fiber size. Therefore, we conclude that the activation of mTOR signaling is both necessary and sufficient to alleviate the decreases in protein synthesis and muscle mass that occur during immobilization. Furthermore, these results indicate

  6. Increase in relative skeletal muscle mass over time and its inverse association with metabolic syndrome development: a 7-year retrospective cohort study.

    PubMed

    Kim, Gyuri; Lee, Seung-Eun; Jun, Ji Eun; Lee, You-Bin; Ahn, Jiyeon; Bae, Ji Cheol; Jin, Sang-Man; Hur, Kyu Yeon; Jee, Jae Hwan; Lee, Moon-Kyu; Kim, Jae Hyeon

    2018-02-05

    Skeletal muscle mass was negatively associated with metabolic syndrome prevalence in previous cross-sectional studies. The aim of this study was to investigate the impact of baseline skeletal muscle mass and changes in skeletal muscle mass over time on the development of metabolic syndrome in a large population-based 7-year cohort study. A total of 14,830 and 11,639 individuals who underwent health examinations at the Health Promotion Center at Samsung Medical Center, Seoul, Korea were included in the analyses of baseline skeletal muscle mass and those changes from baseline over 1 year, respectively. Skeletal muscle mass was estimated by bioelectrical impedance analysis and was presented as a skeletal muscle mass index (SMI), a body weight-adjusted appendicular skeletal muscle mass value. Using Cox regression models, hazard ratio for developing metabolic syndrome associated with SMI values at baseline or changes of SMI over a year was analyzed. During 7 years of follow-up, 20.1% of subjects developed metabolic syndrome. Compared to the lowest sex-specific SMI tertile at baseline, the highest sex-specific SMI tertile showed a significant inverse association with metabolic syndrome risk (adjusted hazard ratio [AHR] = 0.61, 95% confidence interval [CI] 0.54-0.68). Furthermore, compared with SMI changes < 0% over a year, multivariate-AHRs for metabolic syndrome development were 0.87 (95% CI 0.78-0.97) for 0-1% changes and 0.67 (0.56-0.79) for > 1% changes in SMI over 1 year after additionally adjusting for baseline SMI and glycometabolic parameters. An increase in relative skeletal muscle mass over time has a potential preventive effect on developing metabolic syndrome, independently of baseline skeletal muscle mass and glycometabolic parameters.

  7. Rat hindlimb muscle responses to suspension hypokinesia/hypodynamia

    NASA Technical Reports Server (NTRS)

    Musacchia, X. J.; Steffen, J. M.; Deavers, D. R.

    1983-01-01

    Hypokinetic/hyupodynamic (H/H) whole body suspension of rats eliminates hindlimb load bearing functions while permitting continued use of the forelimbs. Responses of hindlimb muscles were assessed in terms of absolute and relative weights during 1 and 2 weeks of H/H suspension. Muscle mass loss was in the order soleus greater than gastrocnemius equal to plantaris greater than extensor digitorum longus (EDL). The soleus, a postural antigravity muscle composed mainly of slow twitch fibers, was most sensitive, losing 35 and 45 percent of its weight during the first and second weeks, respectively. The gastrocnemius and plantaris showed losses during the first week but no significant loss during the second wee. The EDL showed little or no weight loss. During post suspension recovery all muscles showed a weight gain. H/H suspended rats failed to grow; following removal from suspension they gained weight linearly, comparable to controls. Products of muscle metabolism including urea, ammonia, and 3-methylhistidine increased in the urine during H/H suspension and were significantly reduced approaching control levels during recovery. This suspension model offers considerable promise for comparison with H/H responses during weightlessness.

  8. Muscle quality, aerobic fitness and fat mass predict lower-extremity physical function in community-dwelling older adults.

    PubMed

    Misic, Mark M; Rosengren, Karl S; Woods, Jeffrey A; Evans, Ellen M

    2007-01-01

    Muscle mass, strength and fitness play a role in lower-extremity physical function (LEPF) in older adults; however, the relationships remain inadequately characterized. This study aimed to examine the relationships between leg mineral free lean mass (MFLM(LEG)), leg muscle quality (leg strength normalized for MFLM(LEG)), adiposity, aerobic fitness and LEPF in community-dwelling healthy elderly subjects. Fifty-five older adults (69.3 +/- 5.5 years, 36 females, 19 males) were assessed for leg strength using an isokinetic dynamometer, body composition by dual energy X-ray absorptiometry and aerobic fitness via a treadmill maximal oxygen consumption test. LEPF was assessed using computerized dynamic posturography and stair ascent/descent, a timed up-and-go task and a 7-meter walk with and without an obstacle. Muscle strength, muscle quality and aerobic fitness were similarly correlated with static LEPF tests (r range 0.27-0.40, p < 0.05); however, the strength of the independent predictors was not robust with explained variance ranging from 9 to 16%. Muscle quality was the strongest correlate of all dynamic LEPF tests (r range 0.54-0.65, p < 0.001). Using stepwise linear regression analysis, muscle quality was the strongest independent predictor of dynamic physical function explaining 29-42% of the variance (p < 0.001), whereas aerobic fitness or body fat mass explained 5-6% of the variance (p < 0.05) depending on performance measure. Muscle quality is the most important predictor, and aerobic fitness and fat mass are secondary predictors of LEPF in community-dwelling older adults. These findings support the importance of exercise, especially strength training, for optimal body composition, and maintenance of strength and physical function in older adults.

  9. Sex and race/ethnic disparities in the cross-sectional association between depressive symptoms and muscle mass: the Multi-ethnic Study of Atherosclerosis.

    PubMed

    Remigio-Baker, Rosemay A; Allison, Matthew A; Schreiner, Pamela J; Carnethon, Mercedes R; Nettleton, Jennifer A; Mujahid, Mahasin S; Szklo, Moyses; Crum, Rosa M; Leuotsakos, Jeannie-Marie; Franco, Manuel; Jensky, Nicole; Golden, Sherita Hill

    2015-09-18

    The cross-sectional area of total muscle mass has been reported to decrease by about 40% for those 20-60 years of age. Depressive symptoms may discourage motivation to engage in physical activity such as strength training shown to negate muscle loss. Inflammation related to depressive symptoms may also contribute to muscle atrophy. Physiological differences by sex and race/ethnicity may also modify the association between depression and muscle mass. Evidence on the relationship between depression (or depressive symptoms) and adiposity has been mounting; however, little is known about the depressive symptoms-muscle mass association. We sought to determine the association between elevated depressive symptoms (EDS) and lean muscle mass and whether this varies by sex and race/ethnicity. Evaluating 1605 adults (45-84 years of age) from the Multi-ethnic Study of Atherosclerosis Abdominal Body Composition, Inflammation and Cardiovascular Disease Study, we examined the cross-sectional association between EDS (Center for Epidemiologic Studies for Depression Scale score≥16 and/or antidepressant use) and computed tomography-measured abdominal lean muscle mass using linear regression. Muscles were evaluated as a whole and by functionality (locomotion vs. stabilization/posture). Covariates included height, body mass index, sociodemographics, comorbidities, inflammatory markers and health behaviors (pack-years of smoking, alcohol locomotion compared to men, total intentional exercise, daily caloric intake). Sex and race/ethnicity were assessed as potential modifiers. Statistical significance was at a p<0.05 for main effects and <0.20 for interaction. Men with elevated depressive symptoms had 5.9 cm2 lower lean muscle mass for locomotion compared to men without EDS, fully-adjusted (CI=-10.5, -1.4, p=0.011). This was statistically significantly different from the null finding among women (interaction p=0.05). Chinese participants with EDS had 10.2 cm2 lower abdominal lean muscle

  10. Creatine ( methyl-d3) dilution in urine for estimation of total body skeletal muscle mass: accuracy and variability vs. MRI and DXA.

    PubMed

    Clark, Richard V; Walker, Ann C; Miller, Ram R; O'Connor-Semmes, Robin L; Ravussin, Eric; Cefalu, William T

    2018-01-01

    A noninvasive method to estimate muscle mass based on creatine ( methyl-d 3 ) (D 3 -creatine) dilution using fasting morning urine was evaluated for accuracy and variability over a 3- to 4-mo period. Healthy older (67- to 80-yr-old) subjects ( n = 14) with muscle wasting secondary to aging and four patients with chronic disease (58-76 yr old) fasted overnight and then received an oral 30-mg dose of D 3 -creatine at 8 AM ( day 1). Urine was collected during 4 h of continued fasting and then at consecutive 4- to 8-h intervals through day 5. Assessment was repeated 3-4 mo later in 13 healthy subjects and 1 patient with congestive heart failure. Deuterated and unlabeled creatine and creatinine were measured using liquid chromatography-tandem mass spectrometry. Total body creatine pool size and muscle mass were calculated from D 3 -creatinine enrichment in urine. Muscle mass was also measured by whole body MRI and 24-h urine creatinine, and lean body mass (LBM) was measured by dual-energy X-ray absorptiometry (DXA). D 3 -creatinine urinary enrichment from day 5 provided muscle mass estimates that correlated with MRI for all subjects ( r = 0.88, P < 0.0001), with less bias [difference from MRI = -3.00 ± 2.75 (SD) kg] than total LBM assessment by DXA, which overestimated muscle mass vs. MRI (+22.5 ± 3.7 kg). However, intraindividual variability was high with the D 3 -creatine dilution method, with intrasubject SD for estimated muscle mass of 2.5 kg vs. MRI (0.5 kg) and DXA (0.8 kg). This study supports further clinical validation of the D 3 -creatine method for estimating muscle mass. NEW & NOTEWORTHY Measurement of creatine ( methyl-d 3 ) (D 3 -creatine) and D 3 -creatinine excretion in fasted morning urine samples may be a simple, less costly alternative to MRI or dual-energy X-ray absorptiometry (DXA) to calculate total body muscle mass. The D 3 -creatine enrichment method provides estimates of muscle mass that correlate well with MRI, and with less

  11. Relationship between Handgrip Strength and Muscle Mass in Female Survivors of Breast Cancer: A Mediation Analysis.

    PubMed

    Benavides-Rodríguez, Lorena; García-Hermoso, Antonio; Rodrigues-Bezerra, Diogo; Izquierdo, Mikel; Correa-Bautista, Jorge Enrique; Ramírez-Vélez, Robinson

    2017-07-04

    This study explored the mediating factors of sarcopenia in a group of women survivors of breast cancer in Bogotá, Colombia. This was a descriptive cross-sectional study with 98 women survivors of breast cancer, who were registered with the SIMMON (Integrated Synergies to Improve Oncological Management in Colombia) Foundation. Body weight, height, and waist circumference (WC) were measured, and body mass index (BMI) was calculated. Body composition (percentage of fat and muscle mass) was evaluated via four-pole bioelectrical impedance analysis. Sarcopenia was defined as low muscle mass plus low grip strength or low gait speed (European Working Group on Sarcopenia in Older People (EWGSOP) criteria). A "causal" mediation analysis with the Baron & Kenny procedure (PROCESS ® macro, Columbus, OH, USA) was used to explore variables related to sarcopenia. Analyses were performed with the IBM SPSS 21 statistical package (SPSS Inc., Chicago, IL, USA). The significance level of the results obtained in the hypothesis contrast was p < 0.05. The mean age of the sample was 65.5 ± 5.9 years, with a BMI of 27.8 ± 4.7 kg/m². The prevalence of sarcopenia was 22.4%. Linear regression models suggest a partial mediation of anthropometric parameters (body mass, body mass index and waist circumference) in the association between handgrip strength and muscle mass. In conclusion, one in every five women survivors of breast cancer had sarcopenia. The findings seem to emphasize the importance of obesity prevention in women survivors of breast cancer, suggesting that high handgrip strength may not relate closely to greater muscle mass and therefore would not exclude the risk of sarcopenia.

  12. Relationship between Handgrip Strength and Muscle Mass in Female Survivors of Breast Cancer: A Mediation Analysis

    PubMed Central

    Benavides-Rodríguez, Lorena; Rodrigues-Bezerra, Diogo; Correa-Bautista, Jorge Enrique

    2017-01-01

    This study explored the mediating factors of sarcopenia in a group of women survivors of breast cancer in Bogotá, Colombia. This was a descriptive cross-sectional study with 98 women survivors of breast cancer, who were registered with the SIMMON (Integrated Synergies to Improve Oncological Management in Colombia) Foundation. Body weight, height, and waist circumference (WC) were measured, and body mass index (BMI) was calculated. Body composition (percentage of fat and muscle mass) was evaluated via four-pole bioelectrical impedance analysis. Sarcopenia was defined as low muscle mass plus low grip strength or low gait speed (European Working Group on Sarcopenia in Older People (EWGSOP) criteria). A “causal” mediation analysis with the Baron & Kenny procedure (PROCESS® macro, Columbus, OH, USA) was used to explore variables related to sarcopenia. Analyses were performed with the IBM SPSS 21 statistical package (SPSS Inc., Chicago, IL, USA). The significance level of the results obtained in the hypothesis contrast was p < 0.05. The mean age of the sample was 65.5 ± 5.9 years, with a BMI of 27.8 ± 4.7 kg/m2. The prevalence of sarcopenia was 22.4%. Linear regression models suggest a partial mediation of anthropometric parameters (body mass, body mass index and waist circumference) in the association between handgrip strength and muscle mass. In conclusion, one in every five women survivors of breast cancer had sarcopenia. The findings seem to emphasize the importance of obesity prevention in women survivors of breast cancer, suggesting that high handgrip strength may not relate closely to greater muscle mass and therefore would not exclude the risk of sarcopenia. PMID:28677652

  13. Impact of low skeletal muscle mass and density on short and long-term outcome after resection of stage I-III colorectal cancer.

    PubMed

    van Vugt, Jeroen L A; Coebergh van den Braak, Robert R J; Lalmahomed, Zarina S; Vrijland, Wietske W; Dekker, Jan W T; Zimmerman, David D E; Vles, Wouter J; Coene, Peter-Paul L O; IJzermans, Jan N M

    2018-06-06

    Preoperative low skeletal muscle mass and density are associated with increased postoperative morbidity in patients undergoing curative colorectal cancer (CRC) surgery. However, the long-term effects of low skeletal muscle mass and density remain uncertain. Patients with stage I-III CRC undergoing surgery, enrolled in a prospective observational cohort study, were included. Skeletal muscle mass and density were measured on CT. Patients with high and low skeletal muscle mass and density were compared regarding postoperative complications, disease-free survival (DFS), overall survival (OS), and cancer-specific survival (CSS). In total, 816 patients (53.9% males, median age 70) were included; 50.4% had low skeletal muscle mass and 64.1% low density. The severe postoperative complication rate was significantly higher in patients with low versus high skeletal muscle and density (20.9% versus 13.6%, p = 0.006; 20.0% versus 11.8%, p = 0.003). Low skeletal muscle mass (OR 1.91, p = 0.018) and density (OR 1.87, p = 0.045) were independently associated with severe postoperative complications. Ninety-day mortality was higher in patients with low skeletal muscle mass and density compared with patients with high skeletal muscle mass and density (3.6% versus 1.7%, p = 0.091; 3.4% versus 1.0%, p = 0.038). No differences in DFS were observed. After adjustment for covariates such as age and comorbidity, univariate differences in OS and CSS diminished. Low skeletal muscle mass and density are associated with short-term, but not long-term, outcome in patients undergoing CRC surgery. These findings recommend putting more emphasis on preoperative management of patients at risk for surgical complications, but do not support benefit for long-term outcome. Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

  14. Proposal for new diagnostic criteria for low skeletal muscle mass based on computed tomography imaging in Asian adults.

    PubMed

    Hamaguchi, Yuhei; Kaido, Toshimi; Okumura, Shinya; Kobayashi, Atsushi; Hammad, Ahmed; Tamai, Yumiko; Inagaki, Nobuya; Uemoto, Shinji

    2016-01-01

    Low skeletal muscle, referred to as sarcopenia, has been shown to be an independent predictor of lower overall survival in various kinds of diseases. Several studies have evaluated the low skeletal muscle mass using computed tomography (CT) imaging. However, the cutoff values based on CT imaging remain undetermined in Asian populations. Preoperative plain CT imaging at the third lumbar vertebrae level was used to measure the psoas muscle mass index (PMI, cm(2)/m(2)) in 541 adult donors for living donor liver transplantation (LDLT). We analyzed PMI distribution according to sex or donor age, and determined the sex-specific cutoff values of PMI to define low skeletal muscle mass. PMI in men was significantly higher than observed in women (8.85 ± 1.61 cm(2)/m(2) versus 5.77 ± 1.21 cm(2)/m(2); P < 0.001). PMI was significantly lower in individuals ≥50 y than in younger donors in both men and women (P < 0.001 and P < 0.001, respectively). On the basis of the younger donor data, we determined the sex-specific cutoff values for the low skeletal muscle mass were 6.36 cm(2)/m(2) for men and 3.92 cm(2)/m(2) for women (mean - 2 SD). Data from healthy young Asian adults were used to establish new criteria for low skeletal muscle mass that would be applicable for defining sarcopenia in Asian populations. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Strain in shock-loaded skeletal muscle and the time scale of muscular wobbling mass dynamics.

    PubMed

    Christensen, Kasper B; Günther, Michael; Schmitt, Syn; Siebert, Tobias

    2017-10-16

    In terrestrial locomotion, muscles undergo damped oscillations in response to limb impacts with the ground. Muscles are also actuators that generate mechanical power to allow locomotion. The corresponding elementary contractile process is the work stroke of an actin-myosin cross-bridge, which may be forcibly detached by superposed oscillations. By experimentally emulating rat leg impacts, we found that full activity and non-fatigue must meet to possibly prevent forcible cross-bridge detachment. Because submaximal muscle force represents the ordinary locomotor condition, our results show that forcible, eccentric cross-bridge detachment is a common, physiological process even during isometric muscle contractions. We also calculated the stiffnesses of the whole muscle-tendon complex and the fibre material separately, as well as Young's modulus of the latter: 1.8 MPa and 0.75 MPa for fresh, fully active and passive fibres, respectively. Our inferred Young's modulus of the tendon-aponeurosis complex suggests that stiffness in series to the fibre material is determined by the elastic properties of the aponeurosis region, rather than the tendon material. Knowing these stiffnesses and the muscle mass, the complex' eigenfrequency for responses to impacts can be quantified, as well as the size-dependency of this time scale of muscular wobbling mass dynamics.

  16. Low appendicular skeletal muscle mass (ASM) with limited mobility and poor health outcomes in middle-aged African Americans.

    PubMed

    Malmstrom, Theodore K; Miller, Douglas K; Herning, Margaret M; Morley, John E

    2013-09-01

    Recent efforts to provide a consensus definition propose that sarcopenia be considered a clinical syndrome associated with the loss of both skeletal muscle mass and muscle function that occurs with aging. Validation of sarcopenia definitions that include both low muscle mass and poor muscle function is needed. In the population-based African American Health (AAH) study (N = 998 at baseline/wave 1), muscle mass and mobility were evaluated in a clinical testing center in a subsample of N = 319 persons (ages 52-68) at wave 4 (2004). Muscle mass was measured using dual energy x-ray absorptiometry and mobility by a 6-min walk test and 4-m gait walk test. Height corrected appendicular skeletal mass (ASM; 9.0 ± 1.5 in n = 124 males, 8.3 ± 2.2 in n = 195 females) was computed as total lean muscle mass in arms and legs (kilograms) divided by the square of height (meters). Cross-sectional and longitudinal (6-year) associations of low ASM (bottom 25 % AAH sample; <7.96 males and <7.06 females) and low ASM with limited mobility (4-m gait walk ≤1 m/s or 6-min walk <400 m) were examined for basic activities of daily living (ADL) difficulties, instrumental activities of daily living (IADL) difficulties, frailty, falls, and mortality (longitudinal only). Low ASM with limited mobility was associated with IADL difficulties (p = .008) and frailty (p = .040) but not with ADL difficulties or falls in cross-sectional analyses; and with ADL difficulties (p = .022), IADL difficulties (p = .006), frailty (p = .039), and mortality (p = .003) but not with falls in longitudinal analyses adjusted for age and gender. Low ASM alone was marginally associated with mortality (p = .085) but not with other outcomes in cross-sectional or longitudinal analyses. Low ASM with limited mobility is associated with poor health outcomes among late middle-aged African Americans.

  17. The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise.

    PubMed

    Rossman, Matthew J; Garten, Ryan S; Venturelli, Massimo; Amann, Markus; Richardson, Russell S

    2014-06-15

    Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass.

  18. Analysis of fat and muscle mass in patients with inflammatory bowel disease during remission and active phase.

    PubMed

    Rocha, Raquel; Santana, Genoile Oliveira; Almeida, Neogélia; Lyra, Andre Castro

    2009-03-01

    Inflammatory bowel disease (IBD) is often associated with malnutrition. The aim of this study was to compare the body composition of outpatients with IBD during remission and active phase. In order to evaluate disease activity we used Crohn's Disease Activity Index for Crohn's disease (CD) patients and Lichtiger's Index for ulcerative colitis (UC) patients. All patients underwent the analysis of BMI, arm muscle area (AMA) and triceps plus subscapula skinfold thickness (TST+SST) to identify total, muscle and fat mass, respectively. In total 102 patients were evaluated (CD, n 50; UC, n 52) and the majority was young women. Malnutrition according to BMI was found in 14.0 % of patients with CD and 5.7 % of UC patients. Muscle mass depletion was detected in more than half of the CD and UC patients. The BMI, TST+SST and AMA values were lower in the active phase only in CD patients (P < 0.05). Fat mass depletion was associated with active phase in both CD and UC patients. Body composition parameters obtained using BMI, TST+SST and AMA were not correlated with the presence of fistula in CD patients (P>0.05). In conclusion, patients without signs of malnutrition had fat mass depletion especially in the active phase and muscle mass depletion occurred both in CD and UC patients.

  19. Butyryl-cholinesterase is related to muscle mass and strength. A new biomarker to identify elderly subjects at risk of sarcopenia.

    PubMed

    Cacciatore, Francesco; Della-Morte, David; Basile, Claudia; Curcio, Francesco; Liguori, Ilaria; Roselli, Mario; Gargiulo, Gaetano; Galizia, Gianluigi; Bonaduce, Domenico; Abete, Pasquale

    2015-01-01

    To determine the relationship between Butyryl-cholinesterase (α-glycoprotein synthesized in the liver, b-CHE) and muscle mass and strength. Muscle mass by bioimpedentiometer and muscle strength by grip strength were evaluated in 337 elderly subjects (mean age: 76.2 ± 6.7 years) admitted to comprehensive geriatric assessment. b-CHE levels were lower in sarcopenic than in nonsarcopenic elderly subjects (p < 0.01). Linear regression analysis demonstrated that b-CHE is linearly related with grip strength and muscular mass both in men and women (r = 0.45 and r = 0.33, p < 0.01; r = 0.55 and r = 0.39, p < 0.01; respectively). Multivariate analysis confirms this analysis. b-CHE is related to muscle mass and strength in elderly subjects. Thus, b-CHE may be considered to be a fair biomarker for identifying elderly subjects at risk of sarcopenia.

  20. Absolute mass of neutrinos and the first unique forbidden {beta} decay of {sup 187}Re

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

    Dvornicky, Rastislav; Simkovic, Fedor; Bogoliubov Laboratory of Theoretical Physics, JINR Dubna, 141980 Dubna, Moscow region

    2011-04-15

    The planned rhenium {beta}-decay experiment, called the ''Microcalorimeter Arrays for a Rhenium Experiment'' (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which will take commissioning data in 2011 and will proceed for 5 years. We present the energy distribution of emitted electrons for the first unique forbidden {beta} decay of {sup 187}Re. It is found that the p-wave emission of electron dominates over the s wave. By assuming mixing of three neutrinos, the Kurie function for the rhenium {beta} decay is derived. It is shown that themore » Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed {beta} decay of {sup 3}H.« less

  1. Absolute Quantification of Norovirus Capsid Protein in Food, Water, and Soil Using Synthetic Peptides with Electrospray and MALDI Mass Spectrometry

    PubMed Central

    Hartmann, Erica M.; Colquhoun, David R.; Schwab, Kellogg J.; Halden, Rolf U.

    2015-01-01

    Norovirus infections are one of the most prominent public health problems of microbial origin in the U.S. and other industrialized countries. Surveillance is necessary to prevent secondary infection, confirm successful cleanup after outbreaks, and track the causative agent. Quantitative mass spectrometry, based on absolute quantitation with stable-isotope labeled peptides, is a promising tool for norovirus monitoring because of its speed, sensitivity, and robustness in the face of environmental inhibitors. In the current study, we present two new methods for the detection of the norovirus genogroup I capsid protein using electrospray and matrixassisted laser desorption/ionization (MALDI) mass spectrometry. The peptide TLDPIEVPLEDVR was used to quantify norovirus-like particles down to 500 attomoles with electrospray and 100 attomoles with MALDI. With MALDI, we also demonstrate a detection limit of 1 femtomole and a quantitative dynamic range of 5 orders of magnitude in the presence of an environmental matrix effect. Due to the rapid processing time and applicability to a wide range of environmental sample types (bacterial lysate, produce, milk, soil, and groundwater), mass spectrometry-based absolute quantitation has a strong potential for use in public health and environmental sciences. PMID:25603302

  2. Mass dynamics of wintering Pacific Black Brant: Body, adipose tissue, organ, and muscle masses vary with location

    USGS Publications Warehouse

    Mason, D.D.; Barboza, P.S.; Ward, D.H.

    2007-01-01

    We compared body size and mass of the whole body, organs, adipose tissue, and muscles of adult Pacific Black Brant (Branta bernicla nigricans (Lawrence, 1846)) collected concurrently in Alaska and Baja California during the fall, winter, and spring of 2002–2003. Head and tarsal lengths of males were similar between sites and slightly larger for females in Alaska than in Baja California. Brant appear to operate under similar physiological bounds, but patterns of nutrient allocation differ between sites. Birds wintering in Alaska lost similar amounts of adipose tissue during early winter as birds in Baja California gained during late winter before migration. Masses of the body, adipose tissue, and flight muscles during mid-winter were similar between sites. Seasonal adipose tissue deposition may, therefore, equally favor winter residency or long-distance migration. Gonad and liver masses increased in late winter for birds in Alaska but not for those in Baja California, suggesting birds wintering in Baja may delay reproductive development in favor of allocating reserves needed for migration. Phenotypic flexibility allows Brant to use widely divergent wintering sites. The wintering location of Brant likely depends more upon changes in environmental conditions and food availability, than upon physiological differences between the two wintering populations.

  3. Interaction of Mechanical Load with Growth Hormone (GH) and Insulin-Like Growth Factor I (IGF-I) on Slow-Twitch Skeletal Muscle and Bone

    NASA Technical Reports Server (NTRS)

    Linderman, Jon K.; Gosselink, Kristin L.; Wang, Tommy J.; Mukku, Venkat R.; Grindeland, Richard E.

    1994-01-01

    Exogenous humoral growth factors, combined with increased mechanical loading, reportedly induce hypertrophy of fast-, but not slow-twitch skeletal muscles, and have little effect in attenuating atrophy of slow-twitch muscle associated with exposure to microgravity in animals with intact neuroendocrine systems. These observations suggest that anabolic adjuvants and muscle tension do not interact to stimulate growth or maintenance of slow-twitch skeletal muscle. The purpose of the present study was to determine whether a chronic increase in mechanical loading (synergistic ablation) or hindlimb unweighting (hindlimb suspension) interact with exogenous GH and IGF-I (Genentech, So San Francisco, CA) in the slow-twitch soleus muscles of female rats (approx. 250 g). Bilateral ablation of the plantaris and gastrocnemius muscles induced 38% and 40% increases in the absolute (mg/pair) and relative (mg/100 g body weight) weights of the soleus, respectively (p less than or = 0.05), in ambulatory rats. GH and IGF-I interacted with chronic loading to increase absolute soleus mass an additional 20% (p less than or = 0.05), and mixed and myofibrillar protein contents an additional 12% and 7%, respectively (NS). In contrast, hindlimb suspension (HLS) resulted in 20% and 18% decreases in the absolute and relative weights of the soleus, respectively (p less than or = 0.05); GH and IGF-I did not spare loss of soleus mass or protein content in HLS rats. HLS decreased tibial plate thickness approx. 11% (p less than or = 0.05), but not weights of the tibia or femus. GH and IGF-I increased tibial plate thickness approx. 30% (p less than or = 0.05), in ambulatory and HLS rats, and increased femur and tibial weights 12% (p less than or = 0.05) and 8% (NS), respectively, in ambulatory rats, but had no effect in HLS rats. Results of the present investigation suggest that GH and IGF-I can stimulate hypertrophy of slow-twitch skeletal muscle when chronically overloaded, but can also stimulate

  4. Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

    PubMed Central

    Takano, Yoshio; Yoshimitsu, Kazuhiro; Omoto, Masayuki; Hashida, Ryuki; Tagawa, Yoshihiko; Inada, Tomohisa; Yamada, Shin; Ohshima, Hiroshi

    2015-01-01

    Background Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut’s musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system’s orbital operation capability and utility, as well as its preventative effect on an astronaut’s musculoskeletal atrophy. Methods HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference). Results The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR

  5. Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station.

    PubMed

    Shiba, Naoto; Matsuse, Hiroo; Takano, Yoshio; Yoshimitsu, Kazuhiro; Omoto, Masayuki; Hashida, Ryuki; Tagawa, Yoshihiko; Inada, Tomohisa; Yamada, Shin; Ohshima, Hiroshi

    2015-01-01

    Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut's musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system's orbital operation capability and utility, as well as its preventative effect on an astronaut's musculoskeletal atrophy. HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference). The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR. These results showed the orbital operation

  6. Association between muscle mass and adipo-metabolic profile: a cross-sectional study in older subjects

    PubMed Central

    Perna, Simone; Guido, Davide; Grassi, Mario; Rondanelli, Mariangela

    2015-01-01

    Background Sarcopenia, the decrease in muscle mass and function, may lead to various negative health outcomes in elderly. The association among sarcopenia with adiposity and metabolic markers has rarely been studied in the elderly population, with controversial results. The aim of this study is to evaluate this relationship in older subjects. Methods A cross-sectional study was conducted in 290 elderly patients, focusing on the possible association between muscle mass loss, assessed by relative skeletal muscle mass (RSMM), and an adipo-metabolic profile (AMP) defined by adiposity and metabolic biochemical markers. Measurements of body composition were assessed by dual energy X-ray absorptiometry. Biochemical parameters, such as albumin, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total cholesterol, triglycerides, C-reactive protein, and homocysteine and its related markers (folate and vitamin B12) were measured. Using canonical correlation analysis and structural equation modeling, an individual score of AMP was created and correlated with RSMM. Results The AMP–RSMM correlation was equal to +0.642 (95% confidence interval, +0.512 to +0.773; P<0.001). Hence, a negative association between sarcopenia severity and adiposity/metabolic biochemical markers was highlighted. Conclusion This study contained a novel way to examine the relationship between the variables of interest based on a composite index of adiposity and metabolic conditions. Results shed light on the orientation and magnitude of adiposity and metabolic markers in preventing muscle mass loss. There might be a protective effect of adiposity, compatible with the “obesity paradox.” PMID:25759569

  7. Proteome Analysis Using Isobaric Tags for Relative and Absolute Analysis Quantitation (iTRAQ) Reveals Alterations in Stress-Induced Dysfunctional Chicken Muscle.

    PubMed

    Xing, Tong; Wang, Chong; Zhao, Xue; Dai, Chen; Zhou, Guanghong; Xu, Xinglian

    2017-04-05

    The current study was designed to investigate changes in the protein profiles of pale, soft, and exudative (PSE)-like muscles of broilers subjected to transportation under high-temperature conditions, using isobaric tags for relative and absolute analysis quantitation (iTRAQ). Arbor Acres chickens (n = 112) were randomly divided into two treatments: unstressed control (CON) and 0.5 h of transport (T). Birds were transported according to a designed protocol. Pectoralis major (PM) muscle samples in the T group were collected and classified as normal (T-NOR) or PSE-like (T-PSE). Plasma activities of stress indicators, muscle microstructure, and proteome were measured. Results indicated that broilers in the T-PSE group exhibited higher activities of plasma stress indicators. The microstructure of T-PSE group showed a looser network and larger intercellular spaces in comparison to the other groups. Proteomic analysis, based on iTRAQ, revealed 29 differentially expressed proteins in the T-NOR and T-PSE groups that were involved in protein turnover, signal transduction, stress and defense, calcium handling, cell structure, and metabolism. In particular, proteins relating to the glycolysis pathway, calcium signaling, and molecular chaperones exhibited significant differences that may contribute to the inferior post-mortem meat quality. Overall, the proteomic results provide a further understanding of the mechanism of meat quality changes in response to stress.

  8. Effects of high-intensity exercise and protein supplement on muscle mass in ADL dependent older people with and without malnutrition: a randomized controlled trial.

    PubMed

    Carlsson, M; Littbrand, H; Gustafson, Y; Lundin-Olsson, L; Lindelöf, N; Rosendahl, E; Håglin, L

    2011-08-01

    Loss of muscle mass is common among old people living in institutions but trials that evaluate interventions aimed at increasing the muscle mass are lacking. Objective, participants and intervention: This randomized controlled trial was performed to evaluate the effect of a high-intensity functional exercise program and a timed protein-enriched drink on muscle mass in 177 people aged 65 to 99 with severe physical or cognitive impairments, and living in residential care facilities. Three-month high-intensity exercise was compared with a control activity and a protein-enriched drink was compared with a placebo drink. A bioelectrical impedance spectrometer (BIS) was used in the evaluation. The amount of muscle mass and body weight (BW) were followed-up at three and six months and analyzed in a 2 x 2 factorial ANCOVA, using the intention to treat principle, and controlling for baseline values. At 3-month follow-up there were no differences in muscle mass and BW between the exercise and the control group or between the protein and the placebo group. No interaction effects were seen between the exercise and nutritional intervention. Long-term negative effects on muscle mass and BW was seen in the exercise group at the 6-month follow-up. A three month high-intensity functional exercise program did not increase the amount of muscle mass and an intake of a protein-enriched drink immediately after the exercise did not induce any additional effect on muscle mass. There were negative long-term effects on muscle mass and BW, indicating that it is probably necessary to compensate for an increased energy demand when offering a high-intensity exercise program.

  9. Age associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life

    USDA-ARS?s Scientific Manuscript database

    SUMMARY: This 3 year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of ...

  10. Absolute limit on rotation of gravitationally bound stars

    NASA Astrophysics Data System (ADS)

    Glendenning, N. K.

    1994-03-01

    The authors seek an absolute limit on the rotational period for a neutron star as a function of its mass, based on the minimal constraints imposed by Einstein's theory of relativity, Le Chatelier's principle, causality, and a low-density equation of state, uncertainties which can be evaluated as to their effect on the result. This establishes a limiting curve in the mass-period plane below which no pulsar that is a neutron star can lie. For example, the minimum possible Kepler period, which is an absolute limit on rotation below which mass-shedding would occur, is 0.33 ms for a M = 1.442 solar mass neutron star (the mass of PSR1913+16). If the limit were found to be broken by any pulsar, it would signal that the confined hadronic phase of ordinary nucleons and nuclei is only metastable.

  11. Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases

    PubMed Central

    Chacon-Cabrera, Alba; Lund-Palau, Helena; Gea, Joaquim; Barreiro, Esther

    2016-01-01

    Background Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization. Methods Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations), proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days) of non-invasive hindlimb immobilization (plastic splint, I cohorts) and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts) following a seven-day period of immobilization. Groups of control animals were also used. Results Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis. Conclusions A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised. PMID

  12. Nerve-muscle interactions during flight muscle development in Drosophila

    NASA Technical Reports Server (NTRS)

    Fernandes, J. J.; Keshishian, H.

    1998-01-01

    During Drosophila pupal metamorphosis, the motoneurons and muscles differentiate synchronously, providing an opportunity for extensive intercellular regulation during synapse formation. We examined the existence of such interactions by developmentally delaying or permanently eliminating synaptic partners during the formation of indirect flight muscles. When we experimentally delayed muscle development, we found that although adult-specific primary motoneuron branching still occurred, the higher order (synaptic) branching was suspended until the delayed muscle fibers reached a favourable developmental state. In reciprocal experiments we found that denervation caused a decrease in the myoblast pool. Furthermore, the formation of certain muscle fibers (dorsoventral muscles) was specifically blocked. Exceptions were the adult muscles that use larval muscle fibers as myoblast fusion targets (dorsal longitudinal muscles). However, when these muscles were experimentally compelled to develop without their larval precursors, they showed an absolute dependence on the motoneurons for their formation. These data show that the size of the myoblast pool and early events in fiber formation depend on the presence of the nerve, and that, conversely, peripheral arbor development and synaptogenesis is closely synchronized with the developmental state of the muscle.

  13. Artistic versus rhythmic gymnastics: effects on bone and muscle mass in young girls.

    PubMed

    Vicente-Rodriguez, G; Dorado, C; Ara, I; Perez-Gomez, J; Olmedillas, H; Delgado-Guerra, S; Calbet, J A L

    2007-05-01

    We compared 35 prepubertal girls, 9 artistic gymnasts and 13 rhythmic gymnasts with 13 nonphysically active controls to study the effect of gymnastics on bone and muscle mass. Lean mass, bone mineral content and areal density were measured by dual energy X-ray absorptiometry, and physical fitness was also assessed. The artistic gymnasts showed a delay in pubertal development compared to the other groups (p<0.05). The artistic gymnasts had a 16 and 17 % higher aerobic power and anaerobic capacity, while the rhythmic group had a 14 % higher anaerobic capacity than the controls, respectively (all p<0.05). The artistic gymnasts had higher lean mass (p<0.05) in the whole body and the extremities than both the rhythmic gymnasts and the controls. Body fat mass was 87.5 and 61.5 % higher in the controls than in the artistic and the rhythmic gymnasts (p<0.05). The upper extremity BMD was higher (p<0.05) in the artistic group compared to the other groups. Lean mass strongly correlated with bone mineral content (r=0.84, p<0.001), and multiple regression analysis showed that total lean mass explained 64 % of the variability in whole body bone mineral content, but only 20 % in whole body bone mineral density. Therefore, recreational artistic gymnastic participation is associated with delayed pubertal development, enhanced physical fitness, muscle mass, and bone density in prepubertal girls, eliciting a higher osteogenic stimulus than rhythmic gymnastic.

  14. Nutritional status, muscle mass and strength of elderly in southern Brazil.

    PubMed

    Klee Oehlschlaeger, Maria Helena; Alberici Pastore, Carla; Schüler Cavalli, Adriana; Gonzalez, Maria Cristina

    2014-09-17

    to assess and compare nutritional status and functional capacity of elderly goers of groups for guided physical activity or for guided recreational activities. Cross-sectional study with 210 elderly (60 years old or more) of coexistence groups (for physical or recreational activities). Nutritional status was assessed by the Mini Nutritional Assessment and Body Mass Index. Muscle mass was estimated by calf circumference (cut point of 31cm for both genders) and strength was evaluated by hydraulic dynamometer, which measures the opponent's finger maximal strength. The study was approved by Research Ethics Committee. Were enrolled 106 elderly in recreational group and 104 in physical activity group. Most of the sample (86.7%) were female. The mean age was 69.3 years old. Body Mass Index showed 82.9% of seniors with excessive weight (87.7% in recreational and 77.9% in physical activity group, p=0.04). When assessed by Mini Nutritional Assessment, 22.9% was classified as malnourished or at risk of malnutrition, with no difference between groups. The mean calf circumference was 37.3 ± 4.1 cm, decreasing significantly with aging (p=0.05) and being higher in elderly with higher BMI (p=0.001). Calf circumference was also greater in physical activity group. Muscle strength's mean was 6.77 (IQR: 5.83, 7.90) kg, with significantly higher values among men. There was no significant variation between age, nutritional status or between groups. This study presented as its main findings that most seniors showed no nutritional risk, with high prevalence of overweight. The practice of physical activities was associated with greater CP and greater functionality of the opposing finger muscles, which indicates the importance of maintaining physical activity in the aging process, in order to prevent frailty and disability. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  15. Age-related differences in lean mass, protein synthesis and skeletal muscle markers of proteolysis after bed rest and exercise rehabilitation

    PubMed Central

    Tanner, Ruth E; Brunker, Lucille B; Agergaard, Jakob; Barrows, Katherine M; Briggs, Robert A; Kwon, Oh Sung; Young, Laura M; Hopkins, Paul N; Volpi, Elena; Marcus, Robin L; LaStayo, Paul C; Drummond, Micah J

    2015-01-01

    Abstract Bed rest-induced muscle loss and impaired muscle recovery may contribute to age-related sarcopenia. It is unknown if there are age-related differences in muscle mass and muscle anabolic and catabolic responses to bed rest. A secondary objective was to determine if rehabilitation could reverse bed rest responses. Nine older and fourteen young adults participated in a 5-day bed rest challenge (BED REST). This was followed by 8 weeks of high intensity resistance exercise (REHAB). Leg lean mass (via dual-energy X-ray absorptiometry; DXA) and strength were determined. Muscle biopsies were collected during a constant stable isotope infusion in the postabsorptive state and after essential amino acid (EAA) ingestion on three occasions: before (PRE), after bed rest and after rehabilitation. Samples were assessed for protein synthesis, mTORC1 signalling, REDD1/2 expression and molecular markers related to muscle proteolysis (MURF1, MAFBX, AMPKα, LC3II/I, Beclin1). We found that leg lean mass and strength decreased in older but not younger adults after bedrest (P < 0.05) and was restored after rehabilitation. EAA-induced mTORC1 signalling and protein synthesis increased before bed rest in both age groups (P < 0.05). Although both groups had blunted mTORC1 signalling, increased REDD2 and MURF1 mRNA after bedrest, only older adults had reduced EAA-induced protein synthesis rates and increased MAFBX mRNA, p-AMPKα and the LC3II/I ratio (P < 0.05). We conclude that older adults are more susceptible than young persons to muscle loss after short-term bed rest. This may be partially explained by a combined suppression of protein synthesis and a marginal increase in proteolytic markers. Finally, rehabilitation restored bed rest-induced deficits in lean mass and strength in older adults. Key points Five days of bed rest resulted in a reduction in leg lean mass and strength in older adults. After bed rest, older (but not younger) adults had reduced amino acid

  16. Ageing influence in the evolution of strength and muscle mass in women with fibromyalgia: the al-Ándalus project.

    PubMed

    Latorre-Román, Pedro Ángel; Segura-Jiménez, Víctor; Aparicio, Virginia A; Santos E Campos, María Aparecida; García-Pinillos, Felipe; Herrador-Colmenero, Manuel; Álvarez-Gallardo, Inmaculada C; Delgado-Fernández, Manuel

    2015-07-01

    Fibromyalgia is associated with physical disabilities in daily activities. Moreover, patients with fibromyalgia present similar levels of functional capacity and physical condition than elderly people. The aim of this study was to analyse the evolution of strength and muscle mass in women with fibromyalgia along ageing. A total sample of 492 fibromyalgia patients and 279 healthy control women were included in the study. Participants in each group were further divided into four age subgroups: subgroup 1: 30-39 years old, subgroup 2: 40-49 years old, subgroup 3: 50-59 years old and subgroup 4: 60-69 years old. Standardized field-based fitness tests were used to assess muscle strength (30-s chair stand, handgrip strength and arm curl tests). Fibromyalgia patients did not show impairment on muscle mass along ageing, without values of skeletal muscle mass index below 6.76 kg/m(2) in any group. However, in all variables of muscle strength, the fibromyalgia group showed less strength than the healthy group (p < 0.05) for all age groups. As expected, handgrip strength test showed differences along ageing only in the fibromyalgia group (p < 0.001). Age was inversely associated with skeletal muscle mass (r = -0.155, p < 0.01) and handgrip strength (r = -0.230, p < 0.001) in the FM group. Women with fibromyalgia showed a reduction in muscle strength along ageing process, with significantly lower scores than healthy women for each age group, representing a risk of dynapenia.

  17. IGF-I treatment improves the functional properties of fast- and slow-twitch skeletal muscles from dystrophic mice.

    PubMed

    Lynch, G S; Cuffe, S A; Plant, D R; Gregorevic, P

    2001-04-01

    Although insulin-like growth factor-I (IGF-I) has been proposed for use by patients suffering from muscle wasting conditions, few studies have investigated the functional properties of dystrophic skeletal muscle following IGF-I treatment. 129P1 ReJ-Lama2(dy) (129 ReJ dy/dy) dystrophic mice suffer from a deficiency in the structural protein, laminin, and exhibit severe muscle wasting and weakness. We tested the hypothesis that 4 weeks of IGF-I treatment ( approximately 2 mg/kg body mass, 50 g/h via mini-osmotic pump, subcutaneously) would increase the mass and force producing capacity of skeletal muscles from dystrophic mice. IGF-I treatment increased the mass of the extensor digitorum longus (EDL) and soleus muscles of dystrophic mice by 20 and 29%, respectively, compared with untreated dystrophic mice (administered saline-vehicle only). Absolute maximum force (P(o)) of the EDL and soleus muscle was increased by 40 and 32%, respectively, following IGF-I treatment. Specific P(o) (sP(o)) was increased by 23% in the EDL muscles of treated compared with untreated mice, but in the soleus muscle sP(o) was unchanged. IGF-I treatment increased the proportion of type IIB and type IIA fibres and decreased the proportion of type I fibres in the EDL muscles of dystrophic mice. In the soleus muscles of dystrophic mice, IGF-I treatment increased the proportion of type IIA fibres and decreased the proportion of type I fibres. Average fibre cross-sectional area was increased in the EDL and soleus muscles of treated compared with untreated mice. We conclude that IGF-I treatment ameliorates muscle wasting and improves the functional properties of skeletal muscles of dystrophic mice. The findings have important implications for the role of IGF-I in ameliorating muscle wasting associated with the muscular dystrophies.

  18. Muscle abnormalities in osteogenesis imperfecta

    PubMed Central

    Veilleux, L-N.; Trejo, P.; Rauch, F.

    2017-01-01

    Osteogenesis imperfecta (OI) is mainly characterized by bone fragility but muscle abnormalities have been reported both in OI mouse models and in children with OI. Muscle mass is decreased in OI, even when short stature is taken into account. Dynamic muscle tests aiming at maximal eccentric force production reveal functional deficits that can not be explained by low muscle mass alone. However, it appears that diaphyseal bone mass is normally adapted to muscle force. At present the determinants of muscle mass and function in OI have not been clearly defined. Physiotherapy interventions and bisphosphonate treatment appear to have some effect on muscle function in OI. Interventions targeting muscle mass have shown encouraging results in OI animal models and are an interesting area for further research. PMID:28574406

  19. Genetic Variations in the Androgen Receptor Are Associated with Steroid Concentrations and Anthropometrics but Not with Muscle Mass in Healthy Young Men

    PubMed Central

    De Naeyer, Hélène; Bogaert, Veerle; De Spaey, Annelies; Roef, Greet; Vandewalle, Sara; Derave, Wim; Taes, Youri; Kaufman, Jean-Marc

    2014-01-01

    Objective The relationship between serum testosterone (T) levels, muscle mass and muscle force in eugonadal men is incompletely understood. As polymorphisms in the androgen receptor (AR) gene cause differences in androgen sensitivity, no straightforward correlation can be observed between the interindividual variation in T levels and different phenotypes. Therefore, we aim to investigate the relationship between genetic variations in the AR, circulating androgens and muscle mass and function in young healthy male siblings. Design 677 men (25–45 years) were recruited in a cross-sectional, population-based sibling pair study. Methods Relations between genetic variation in the AR gene (CAGn, GGNn, SNPs), sex steroid levels (by LC-MS/MS), body composition (by DXA), muscle cross-sectional area (CSA) (by pQCT), muscle force (isokinetic peak torque, grip strength) and anthropometrics were studied using linear mixed-effect modelling. Results Muscle mass and force were highly heritable and related to age, physical activity, body composition and anthropometrics. Total T (TT) and free T (FT) levels were positively related to muscle CSA, whereas estradiol (E2) and free E2 (FE2) concentrations were negatively associated with muscle force. Subjects with longer CAG repeat length had higher circulating TT, FT, and higher E2 and FE2 concentrations. Weak associations with TT and FT were found for the rs5965433 and rs5919392 SNP in the AR, whereas no association between GGN repeat polymorphism and T concentrations were found. Arm span and 2D:4D finger length ratio were inversely associated, whereas muscle mass and force were not associated with the number of CAG repeats. Conclusions Age, physical activity, body composition, sex steroid levels and anthropometrics are determinants of muscle mass and function in young men. Although the number of CAG repeats of the AR are related to sex steroid levels and anthropometrics, we have no evidence that these variations in the AR gene also

  20. Genetic variations in the androgen receptor are associated with steroid concentrations and anthropometrics but not with muscle mass in healthy young men.

    PubMed

    De Naeyer, Hélène; Bogaert, Veerle; De Spaey, Annelies; Roef, Greet; Vandewalle, Sara; Derave, Wim; Taes, Youri; Kaufman, Jean-Marc

    2014-01-01

    The relationship between serum testosterone (T) levels, muscle mass and muscle force in eugonadal men is incompletely understood. As polymorphisms in the androgen receptor (AR) gene cause differences in androgen sensitivity, no straightforward correlation can be observed between the interindividual variation in T levels and different phenotypes. Therefore, we aim to investigate the relationship between genetic variations in the AR, circulating androgens and muscle mass and function in young healthy male siblings. 677 men (25-45 years) were recruited in a cross-sectional, population-based sibling pair study. Relations between genetic variation in the AR gene (CAGn, GGNn, SNPs), sex steroid levels (by LC-MS/MS), body composition (by DXA), muscle cross-sectional area (CSA) (by pQCT), muscle force (isokinetic peak torque, grip strength) and anthropometrics were studied using linear mixed-effect modelling. Muscle mass and force were highly heritable and related to age, physical activity, body composition and anthropometrics. Total T (TT) and free T (FT) levels were positively related to muscle CSA, whereas estradiol (E2) and free E2 (FE2) concentrations were negatively associated with muscle force. Subjects with longer CAG repeat length had higher circulating TT, FT, and higher E2 and FE2 concentrations. Weak associations with TT and FT were found for the rs5965433 and rs5919392 SNP in the AR, whereas no association between GGN repeat polymorphism and T concentrations were found. Arm span and 2D:4D finger length ratio were inversely associated, whereas muscle mass and force were not associated with the number of CAG repeats. Age, physical activity, body composition, sex steroid levels and anthropometrics are determinants of muscle mass and function in young men. Although the number of CAG repeats of the AR are related to sex steroid levels and anthropometrics, we have no evidence that these variations in the AR gene also affect muscle mass or function.

  1. Ribosome abundance regulates the recovery of skeletal muscle protein mass upon recuperation from postnatal undernutrition in mice

    PubMed Central

    Fiorotto, Marta L; Davis, Teresa A; Sosa, Horacio A; Villegas-Montoya, Carolina; Estrada, Irma; Fleischmann, Ryan

    2014-01-01

    Nutritionally-induced growth faltering in the perinatal period has been associated with reduced adult skeletal muscle mass; however, the mechanisms responsible for this are unclear. To identify the factors that determine the recuperative capacity of muscle mass, we studied offspring of FVB mouse dams fed a protein-restricted diet during gestation (GLP) or pups suckled from postnatal day 1 (PN1) to PN11 (E-UN), or PN11 to PN22 (L-UN) on protein-restricted or control dams. All pups were refed under control conditions following the episode of undernutrition. Before refeeding, and 2, 7 and 21 days later, muscle protein synthesis was measured in vivo. There were no long-term deficits in protein mass in GLP and E-UN offspring, but in L-UN offspring muscle protein mass remained significantly smaller even after 18 months (P < 0.001). E-UN differed from L-UN offspring by their capacity to upregulate postprandial muscle protein synthesis when refed (P < 0.001), a difference that was attributable to a transient increase in ribosomal abundance, i.e. translational capacity, in E-UN offspring (P < 0.05); translational efficiency was similar across dietary treatments. The postprandial phosphorylation of Akt and extracellular signal-regulated protein kinases were similar among treatments. However, activation of the ribosomal S6 kinase 1 via mTOR (P < 0.02), and total upstream binding factor abundance were significantly greater in E-UN than L-UN offspring (P < 0.02). The results indicate that the capacity of muscles to recover following perinatal undernutrition depends on developmental age as this establishes whether ribosome abundance can be enhanced sufficiently to promote the protein synthesis rates required to accelerate protein deposition for catch-up growth. PMID:25239457

  2. Structural Characterization and Absolute Quantification of Microcystin Peptides Using Collision-Induced and Ultraviolet Photo-Dissociation Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Attard, Troy J.; Carter, Melissa D.; Fang, Mengxuan; Johnson, Rudolph C.; Reid, Gavin E.

    2018-05-01

    Microcystin (MC) peptides produced by cyanobacteria pose a hepatotoxic threat to human health upon ingestion from contaminated drinking water. While rapid MC identification and quantification in contaminated body fluids or tissue samples is important for patient treatment and outcomes, conventional immunoassay-based measurement strategies typically lack the specificity required for unambiguous determination of specific MC variants, whose toxicity can significantly vary depending on their structures. Furthermore, the unambiguous identification and accurate quantitation of MC variants using tandem mass spectrometry (MS/MS)-based methods can be limited due to a current lack of appropriate stable isotope-labeled internal standards. To address these limitations, we have systematically examined here the sequence and charge state dependence to the formation and absolute abundance of both "global" and "variant-specific" product ions from representative MC-LR, MC-YR, MC-RR, and MC-LA peptides, using higher-energy collisional dissociation (HCD)-MS/MS, ion-trap collision-induced dissociation (CID)-MS/MS and CID-MS3, and 193 nm ultraviolet photodissociation (UPVD)-MS/MS. HCD-MS/MS was found to provide the greatest detection sensitivity for both global and variant-specific product ions in each of the MC variants, except for MC-YR where a variant-specific product uniquely formed via UPVD-MS/MS was observed with the greatest absolute abundance. A simple methodology for the preparation and characterization of 18O-stable isotope-labeled MC reference materials for use as internal standards was also developed. Finally, we have demonstrated the applicability of the methods developed herein for absolute quantification of MC-LR present in human urine samples, using capillary scale liquid chromatography coupled with ultra-high resolution / accurate mass spectrometry and HCD-MS/MS.

  3. Role of Protein Carbonylation in Skeletal Muscle Mass Loss Associated with Chronic Conditions

    PubMed Central

    Barreiro, Esther

    2016-01-01

    Muscle dysfunction, characterized by a reductive remodeling of muscle fibers, is a common systemic manifestation in highly prevalent conditions such as chronic heart failure (CHF), chronic obstructive pulmonary disease (COPD), cancer cachexia, and critically ill patients. Skeletal muscle dysfunction and impaired muscle mass may predict morbidity and mortality in patients with chronic diseases, regardless of the underlying condition. High levels of oxidants may alter function and structure of key cellular molecules such as proteins, DNA, and lipids, leading to cellular injury and death. Protein oxidation including protein carbonylation was demonstrated to modify enzyme activity and DNA binding of transcription factors, while also rendering proteins more prone to proteolytic degradation. Given the relevance of protein oxidation in the pathophysiology of many chronic conditions and their comorbidities, the current review focuses on the analysis of different studies in which the biological and clinical significance of the modifications induced by reactive carbonyls on proteins have been explored so far in skeletal muscles of patients and animal models of chronic conditions such as COPD, disuse muscle atrophy, cancer cachexia, sepsis, and physiological aging. Future research will elucidate the specific impact and sites of reactive carbonyls on muscle protein content and function in human conditions. PMID:28248228

  4. Deep Proteomics of Mouse Skeletal Muscle Enables Quantitation of Protein Isoforms, Metabolic Pathways, and Transcription Factors*

    PubMed Central

    Deshmukh, Atul S.; Murgia, Marta; Nagaraj, Nagarjuna; Treebak, Jonas T.; Cox, Jürgen; Mann, Matthias

    2015-01-01

    Skeletal muscle constitutes 40% of individual body mass and plays vital roles in locomotion and whole-body metabolism. Proteomics of skeletal muscle is challenging because of highly abundant contractile proteins that interfere with detection of regulatory proteins. Using a state-of-the art MS workflow and a strategy to map identifications from the C2C12 cell line model to tissues, we identified a total of 10,218 proteins, including skeletal muscle specific transcription factors like myod1 and myogenin and circadian clock proteins. We obtain absolute abundances for proteins expressed in a muscle cell line and skeletal muscle, which should serve as a valuable resource. Quantitation of protein isoforms of glucose uptake signaling pathways and in glucose and lipid metabolic pathways provides a detailed metabolic map of the cell line compared with tissue. This revealed unexpectedly complex regulation of AMP-activated protein kinase and insulin signaling in muscle tissue at the level of enzyme isoforms. PMID:25616865

  5. Poor physical function in elderly women in low-level aged care is related to muscle strength rather than to measures of sarcopenia.

    PubMed

    Woods, Julie L; Iuliano-Burns, Sandra; King, Susannah J; Strauss, Boyd J; Walker, Karen Z

    2011-01-01

    To determine the prevalence of sarcopenia and investigate relationships among body composition, muscle strength, and physical function in elderly women in low-level aged care. Sixty-three ambulatory women (mean age 86 years) participated in this cross-sectional study where body composition was determined by dual energy X-ray absorptiometry (DXA); ankle, knee, and hip strength by the Nicholas Manual Muscle Tester; and physical function by 'timed up and go' (TUG) and walking speed (WS) over 6 meters. Body composition data from a female reference group (n = 62, mean age 29 years) provided cut-off values for defining sarcopenia. Elderly women had higher body mass index (P < 0.001), lower lean mass (P < 0.001), and higher fat mass (P < 0.01) than the young reference group. Only a small proportion (3.2%) had absolute sarcopenia (defined by appendicular skeletal muscle mass/height squared) whereas 37% had relative sarcopenia class II (defined by percentage skeletal muscle mass). Scores for TUG and WS indicated relatively poor physical function, yet these measures were not associated with muscle mass or indices of sarcopenia. In multivariate analysis, only hip abductor strength predicted both TUG and WS (both P = 0.01). Hip strength is a more important indicator of physical functioning than lean mass. Measurement of hip strength may therefore be a useful screening tool to detect those at risk of functional decline and requirement for additional care. Further longitudinal studies with a range of other strength measures are warranted.

  6. Single cross-sectional area of pectoralis muscle by computed tomography - correlation with bioelectrical impedance based skeletal muscle mass in healthy subjects.

    PubMed

    Kim, Young Saing; Kim, Eun Young; Kang, Shin Myung; Ahn, Hee Kyung; Kim, Hyung Sik

    2017-09-01

    Skeletal muscle depletion is an important prognostic factor in patients with chronic obstructive pulmonary disease (COPD); a recent study demonstrated significant correlations between pectoralis muscle area on an axial CT image and COPD-related traits. The purpose of this study was to evaluate the relation between pectoralis muscle areas on CT scans and total body skeletal muscle mass (SMM) in healthy subjects. For 434 subjects that underwent a low-dose chest CT and bioelectrical impedance analysis (BIA) during health screening from January to June of 2014, cross-sectional area of pectoralis muscles were measured in CT scans. Pearson's correlation and multiple linear regression analysis were used to assess the relationship between cross-sectional CT areas of pectoralis muscles and BIA-assessed SMMs. Mean age was 50 ± 10 years (78·8% were male). The mean cross-sectional area of pectoralis muscles was 24·1 cm 2  ± 6·8. A moderate correlation was observed between pectoralis muscle area and BIA-based SMM (r = 0·665, P<0.001). Multivariable analysis showed CT determined pectoralis muscle area was significantly associated with BIA-assessed SMM after adjusting for gender, weight, height and age (β = 0·14 ± 0·02, P<0·001). Cross-sectional area of the pectoralis muscles on single axial CT images shows moderate correlation with total body SMM determined by BIA in healthy subjects. © 2015 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. Characterization of muscle ankyrin repeat proteins in human skeletal muscle.

    PubMed

    Wette, Stefan G; Smith, Heather K; Lamb, Graham D; Murphy, Robyn M

    2017-09-01

    Muscle ankyrin repeat proteins (MARPs) are a family of titin-associated, stress-response molecules and putative transducers of stretch-induced signaling in skeletal muscle. In cardiac muscle, cardiac ankyrin repeat protein (CARP) and diabetes-related ankyrin repeat protein (DARP) reportedly redistribute from binding sites on titin to the nucleus following a prolonged stretch. However, it is unclear whether ankyrin repeat domain protein 2 (Ankrd 2) shows comparable stretch-induced redistribution to the nucleus. We measured the following in rested human skeletal muscle: 1 ) the absolute amount of MARPs and 2 ) the distribution of Ankrd 2 and DARP in both single fibers and whole muscle preparations. In absolute amounts, Ankrd 2 is the most abundant MARP in human skeletal muscle, there being ~3.1 µmol/kg, much greater than DARP and CARP (~0.11 and ~0.02 µmol/kg, respectively). All DARP was found to be tightly bound at cytoskeletal (or possibly nuclear) sites. In contrast, ~70% of the total Ankrd 2 is freely diffusible in the cytosol [including virtually all of the phosphorylated (p)Ankrd 2-Ser99 form], ~15% is bound to non-nuclear membranes, and ~15% is bound at cytoskeletal sites, likely at the N2A region of titin. These data are not consistent with the proposal that Ankrd 2, per se, or pAnkrd 2-Ser99 mediates stretch-induced signaling in skeletal muscle, dissociating from titin and translocating to the nucleus, because the majority of these forms of Ankrd 2 are already free in the cytosol. It will be necessary to show that the titin-associated Ankrd 2 is modified by stretch in some as-yet-unidentified way, distinct from the diffusible pool, if it is to act as a stretch-sensitive signaling molecule. Copyright © 2017 the American Physiological Society.

  8. Molecular mechanism underlying muscle mass retention in hibernating bats: role of periodic arousal.

    PubMed

    Lee, Kisoo; So, Hyekyoung; Gwag, Taesik; Ju, Hyunwoo; Lee, Ju-Woon; Yamashita, Masamichi; Choi, Inho

    2010-02-01

    Hibernators like bats show only marginal muscle atrophy during prolonged hibernation. The current study was designed to test the hypothesis that hibernators use periodic arousal to increase protein anabolism that compensates for the continuous muscle proteolysis during disuse. To test this hypothesis, we investigated the effects of 3-month hibernation (HB) and 7-day post-arousal torpor (TP) followed by re-arousal (RA) on signaling activities in the pectoral muscles of summer-active (SA) and dormant Murina leucogaster bats. The bats did not lose muscle mass relative to body mass during the HB or TP-to-RA period. For the first 30-min following arousal, the peak amplitude and frequency of electromyographic spikes increased 3.1- and 1.4-fold, respectively, indicating massive myofiber recruitment and elevated motor signaling during shivering. Immunoblot analyses of whole-tissue lysates revealed several principal outcomes: (1) for the 3-month HB, the phosphorylation levels of Akt1 (p-Akt1) and p-mTOR decreased significantly compared to SA bats, but p-FoxO1 levels remained unaltered; (2) for the TP-to-RA period, p-Akt1 and p-FoxO1 varied little, while p-mTOR showed biphasic oscillation; (3) proteolytic signals (i.e., atrogin-1, MuRF1, Skp2 and calpain-1) remained constant during the HB and TP-to-RA period. These results suggest that the resistive properties of torpid bat muscle against atrophy might be attained primarily by relatively constant proteolysis in combination with oscillatory anabolic activity (e.g., p-mTOR) corresponding to the frequency of arousals occurring throughout hibernation. (c) 2009 Wiley-Liss, Inc.

  9. Cancer cachexia decreases specific force and accelerates fatigue in limb muscle

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

    Roberts, B.M.; Frye, G.S.; Ahn, B.

    Highlights: •C-26 cancer cachexia causes a significant decrease in limb muscle absolute force. •C-26 cancer cachexia causes a significant decrease in limb muscle specific force. •C-26 cancer cachexia decreases fatigue resistance in the soleus muscle. •C-26 cancer cachexia prolongs time to peak twitch tension in limb muscle. •C-26 cancer cachexia prolongs one half twitch relaxation time in limb muscle. -- Abstract: Cancer cachexia is a complex metabolic syndrome that is characterized by the loss of skeletal muscle mass and weakness, which compromises physical function, reduces quality of life, and ultimately can lead to mortality. Experimental models of cancer cachexia havemore » recapitulated this skeletal muscle atrophy and consequent decline in muscle force generating capacity. However, more recently, we provided evidence that during severe cancer cachexia muscle weakness in the diaphragm muscle cannot be entirely accounted for by the muscle atrophy. This indicates that muscle weakness is not just a consequence of muscle atrophy but that there is also significant contractile dysfunction. The current study aimed to determine whether contractile dysfunction is also present in limb muscles during severe Colon-26 (C26) carcinoma cachexia by studying the glycolytic extensor digitorum longus (EDL) muscle and the oxidative soleus muscle, which has an activity pattern that more closely resembles the diaphragm. Severe C-26 cancer cachexia caused significant muscle fiber atrophy and a reduction in maximum absolute force in both the EDL and soleus muscles. However, normalization to muscle cross sectional area further demonstrated a 13% decrease in maximum isometric specific force in the EDL and an even greater decrease (17%) in maximum isometric specific force in the soleus. Time to peak tension and half relaxation time were also significantly slowed in both the EDL and the solei from C-26 mice compared to controls. Since, in addition to postural control, the

  10. Fluid retention, muscle damage, and altered body composition at the Ultraman triathlon.

    PubMed

    Baur, Daniel A; Bach, Christopher W; Hyder, William J; Ormsbee, Michael J

    2016-03-01

    The primary purpose of this investigation was to determine the effects of participation in a 3-day multistage ultraendurance triathlon (stage 1 = 10 km swim, 144.8 km bike; stage 2 = 275.4 km bike; stage 3 = 84.4 km run) on body mass and composition, hydration status, hormones, muscle damage, and blood glucose. Eighteen triathletes (mean ± SD; age 41 ± 7.5 years; height 175 ± 9 cm; weight 73.5 ± 9.8 kg; male n = 14, female n = 4) were assessed before and after each stage of the race. Body mass and composition were measured via bioelectrical impedance, hydration status via urine specific gravity, hormones and muscle damage via venous blood draw, and blood glucose via fingerstick. Following the race, significant changes included reductions in body mass (qualified effect size: trivial), fat mass (moderate), and percent body fat (small); increases in percent total body water (moderate) and urine specific gravity (large); and unchanged absolute total body water and fat-free mass. There were also extremely large increases in creatine kinase, C-reactive protein, aldosterone and cortisol combined with reductions in testosterone (small) and the testosterone:cortisol ratio (moderate). There were associations between post-race aldosterone and total body water (r = -0.504) and changes in cortisol and fat-free mass (r = -0.536). Finally, blood glucose increased in a stepwise manner prior to each stage. Participation in Ultraman Florida leads to fluid retention and dramatic alterations in body composition, muscle health, hormones, and metabolism.

  11. Skeletal muscle mass adjusted by height correlated better with muscular functions than that adjusted by body weight in defining sarcopenia.

    PubMed

    Han, Der-Sheng; Chang, Ke-Vin; Li, Chia-Ming; Lin, Yu-Hong; Kao, Tung-Wei; Tsai, Keh-Sung; Wang, Tyng-Grey; Yang, Wei-Shiung

    2016-01-20

    Sarcopenia, characterized by low muscle mass and function, results in frailty, comorbidities and mortality. However, its prevalence varies according to the different criteria used in its diagnosis. This cross-sectional study investigated the difference in the number of sarcopenia cases recorded by two different measurement methods of low muscle mass to determine which measurement was better. We recruited 878 (54.2% female) individuals aged over 65 years and obtained their body composition and functional parameters. Low muscle mass was defined as two standard deviations below either the mean height-adjusted (hSMI) or weight-adjusted (wSMI) muscle mass of a young reference group. The prevalence of sarcopenia was 6.7% vs. 0.4% (male/female) by hSMI, and 4.0% vs. 10.7% (male/female) by wSMI. The κ coefficients for these two criteria were 0.39 vs. 0.03 (male/female), and 0.17 in all subjects. Serum myostatin levels correlated positively with gait speed (r = 0.142, p = 0.007) after adjustment for gender. hSMI correlated with grip strength, cardiopulmonary endurance, leg endurance, gait speed, and flexibility. wSMI correlated with grip strength, leg endurance, gait speed, and flexibility. Since hSMI correlated more closely with grip strength and more muscular functions, we recommend hSMI in the diagnosis of low muscle mass.

  12. Effects of exercise improves muscle strength and fat mass in patients with high fracture risk: A randomized control trial.

    PubMed

    Chan, Ding-Cheng; Chang, Chirn-Bin; Han, Der-Sheng; Hong, Cian-Hui; Hwang, Jawl-Shan; Tsai, Keh-Sung; Yang, Rong-Sen

    2017-10-26

    The deterioration of the musculoskeletal system imposes significant impact on physical activity. Exercise is an important strategy which minimizes these changes. It is not clear which type of exercise provides better improvement on low physical performance, low muscle mass and low strength of sarcopenia. We aim to develop an integrated care (IC) model and compare its relative efficacy in limb fat free mass, muscle strength, and physical performance with low extremities exercise (LEE) in community dwelling older adults with high risk of fractures (Fracture Risk Assessment Tool (FRAX ® )) ≧3% for hip fracture, ≧20% for major osteoporotic fracture or 1-min osteoporosis risk test (≧1 point) or fall (≧2 falls in previous year). Patients were assigned randomized to participate in either IC or LEE group (n = 55 each) for 3 months. All participants received education including home-based exercise. The IC group consisted of different modalities of exercise while the LEE group performed machine-based low extremities exercise. Fat free mass, muscle strength, and physical performance were measured at their baseline and 3-months follow-up. Mean age was 73.8 ± 7 years with 69.1% women. Entire cohort demonstrated significant increment in fat free mass, muscle strength (4 indicators) and physical performance (3 indicators). However, between group differences were not significant. With regular supervise exercise; both groups are equally effective in decreasing fat mass and increasing physical performance, muscle mass and strength. However, the IC group required fewer resources and thus more financially feasible in a community setting. Copyright © 2017. Published by Elsevier B.V.

  13. Ratio of dietary ω-3 and ω-6 fatty acids-independent determinants of muscle mass-in hemodialysis patients with diabetes.

    PubMed

    Wong, Te-Chih; Chen, Yu-Tong; Wu, Pei-Yu; Chen, Tzen-Wen; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Hsu, Yung-Ho; Yang, Shwu-Huey

    2016-09-01

    ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) are essential nutrients in the human diet and possibly affect muscle mass. We evaluated the association between the dietary ratios of ω-3 and ω-6 PUFAs and muscle mass, indicated as skeletal muscle mass (SMM) and appendicular skeletal muscle mass (ASM), in patients with diabetes undergoing hemodialysis (HD). In this cross-sectional study, data on 69 patients with diabetes who underwent standard HD therapy were analyzed. For estimating muscle mass, anthropometric and bioelectrical impedance analyses were conducted following dialysis. In addition, routine laboratory and 3-d dietary data were obtained. The adequate intake (AI) cut-off for ω-3 PUFAs was 1.6 g/d and 1.1 g/d for male and female patients, respectively. The average age of the participants was 63.0 ± 10.4 y. The mean ratios of ω-3/ω-6 PUFA intake, ω-6/ω-3 PUFA intake, SMM, and ASM of the patients were 0.13 ± 0.07, 9.4 ± 6.4, 24.6 ± 5.4 kg, and 18.3 ± 4.6 kg, respectively. Patients who had AI of ω-3 PUFAs had significantly higher SMM and ASM than did their counterparts. Linear and stepwise multivariable adjustment analyses revealed that insulin resistance and the ω-6/ω-3 PUFA ratio were the independent deleterious determinants of ASM normalized to height in HD patients. Patients with AI of ω-3 PUFAs had total-body SMM and ASM that were more appropriate. A higher dietary ratio of ω-6/ω-3 PUFAs was associated with reduced muscle mass in HD patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Lower Jump Power Rather Than Muscle Mass Itself is Associated with Vertebral Fracture in Community-Dwelling Elderly Korean Women.

    PubMed

    Lee, Eun Young; Lee, Su Jin; Kim, Kyoung Min; Seo, Da Hea; Lee, Seung Won; Choi, Han Sol; Kim, Hyeon Chang; Youm, Yoosik; Kim, Chang Oh; Rhee, Yumie

    2017-06-01

    Sarcopenia is considered to be a risk factor for osteoporotic fracture, which is a major health problem in elderly women. In this study, we aimed to investigate the association of sarcopenia, with regard to muscle mass and function, with prevalent vertebral fracture in community-dwelling elderly women. We recruited 1281 women aged 64 to 87 years from the Korean Urban Rural Elderly cohort study. Muscle mass and function were measured using bioimpedance analysis and jumping mechanography. Skeletal muscle index (SMI) and jump power were used as an indicator of muscle mass and function, respectively. Among the participants, we observed 282 (18.9%) vertebral fractures and 564 (44.0%) osteoporosis. Although age, body mass index, and prevalence of osteoporosis increased as both SMI and jump power decreased, prevalence of vertebral fracture increased only when jump power decreased. In univariate analysis, compared with the highest quartile of jump power, the lowest quartile had a significant odds ratio of 2.80 (95% CI 1.79-4.36) for vertebral fracture. This association between jump power and vertebral fracture remained significant, with an odds ratio of 3.04 (95% CI 1.77-5.23), even after adjusting for other risk factors including age, bone mineral density, previous fracture, and cognitive function. In contrast, there was no association between SMI and vertebral fracture. Based on our results, low jump power, but not SMI, is associated with vertebral fracture in community-dwelling elderly Korean women. This finding suggests that jump power may have a more important role than muscle mass itself for osteoporotic fracture.

  15. Two-Year Whey Protein Supplementation Did Not Enhance Muscle Mass and Physical Function in Well-Nourished Healthy Older Postmenopausal Women.

    PubMed

    Zhu, Kun; Kerr, Deborah A; Meng, Xingqiong; Devine, Amanda; Solah, Vicky; Binns, Colin W; Prince, Richard L

    2015-11-01

    Protein may play a role in preventing muscle loss with aging. To our knowledge, there have been no long-term randomized controlled trials to examine the effects of increased dietary protein intake on muscle health in community-dwelling older women. In this study, we evaluated the effects of whey protein supplementation on muscle mass and physical function in community-dwelling older Australian women. In this 2 y randomized, double-blind, placebo-controlled trial, women aged 70-80 y (mean 74.3 ± 2.7 y) were randomly assigned to either a high protein drink containing 30 g of whey protein (n = 109) or a placebo drink containing 2.1 g protein (n = 110) daily. Dual-energy X-ray absorptiometry appendicular skeletal muscle mass, upper arm and calf (38% tibia) muscle cross-sectional area, physical function including hand grip strength, lower limb muscle strength and Timed Up and Go test, and 24 h urinary nitrogen were measured at baseline, 1 y, and 2 y. A total of 196 women with at least one follow-up measurement were included in this analysis. Baseline mean BMI was 26.7 ± 3.9 kg/m(2) and protein intake was 76 ± 17 g/d (1.1 ± 0.3 g · kg body weight(-1) · d(-1)). A mean increase in protein intake of ∼ 20 g/d in the protein group was confirmed by the estimates from 24 h urinary nitrogen. Over the 2 y in both groups there was a significant decrease in the upper arm (mean ± SE: -5.59 ± 0.75 cm(2)) and calf (-0.77 ± 0.11 cm(2)) muscle area, as well as hand grip strength (-1.30 ± 0.3 kg) (all P < 0.05), but appendicular skeletal muscle mass did not change significantly. There were no significant effects of the protein intervention on any of the muscle mass or physical function measures (all P > 0.05) at 1 and 2 y. This study showed that in protein-replete, healthy, ambulant, postmenopausal older women, 30 g/d of extra protein did not improve the maintenance of muscle mass or physical function despite evidence of deterioration in muscle measurements in the upper limb

  16. Age-associated declines in muscle mass, strength, power, and physical performance: impact on fear of falling and quality of life.

    PubMed

    Trombetti, A; Reid, K F; Hars, M; Herrmann, F R; Pasha, E; Phillips, E M; Fielding, R A

    2016-02-01

    This 3-year longitudinal study among older adults showed that declining muscle mass, strength, power, and physical performance are independent contributing factors to increased fear of falling, while declines of muscle mass and physical performance contribute to deterioration of quality of life. Our findings reinforce the importance of preserving muscle health with advancing age. The age-associated loss of skeletal muscle quantity and function are critical determinants of independent physical functioning in later life. Longitudinal studies investigating how decrements in muscle components of sarcopenia impact fear of falling (FoF) and quality of life (QoL) in older adults are lacking. Twenty-six healthy older subjects (age, 74.1 ± 3.7; Short Physical Performance Battery (SPPB) score ≥10) and 22 mobility-limited older subjects (age, 77.2 ± 4.4; SPPB score ≤9) underwent evaluations of lower extremity muscle size and composition by computed tomography, strength and power, and physical performance at baseline and after 3-year follow-up. The Falls Efficacy Scale (FES) and Short Form-36 questionnaire (SF-36) were also administered at both timepoints to assess FoF and QoL, respectively. At 3-year follow-up, muscle cross-sectional area (CSA) (p < 0.013) and power decreased (p < 0.001), while intermuscular fat infiltration increased (p < 0.001). These decrements were accompanied with a longer time to complete 400 m by 22 ± 46 s (p < 0.002). Using linear mixed-effects regression models, declines of muscle CSA, strength and power, and SPPB score were associated with increased FES score (p < 0.05 for each model). Reduced physical component summary score of SF-36 over follow-up was independently associated with decreased SPPB score (p < 0.020), muscle CSA (p < 0.046), and increased 400 m walk time (p < 0.003). In older adults with and without mobility limitations, declining muscle mass, strength, power, and physical

  17. Influence of muscle strength, physical activity and weight on bone mass in a population-based sample of 1004 elderly women.

    PubMed

    Gerdhem, P; Ringsberg, K A M; Akesson, K; Obrant, K J

    2003-09-01

    High physical activity level has been associated with high bone mass and low fracture risk and is therefore recommended to reduce fractures in old age. The aim of this study was to estimate the effect of potentially modifiable variables, such as physical activity, muscle strength, muscle mass and weight, on bone mass in elderly women. The influence of isometric thigh muscle strength, self-estimated activity level, body composition and weight on bone mineral density (dual energy X-ray absorptiometry; DXA) in total body, hip and spine was investigated. Subjects were 1004 women, all 75 years old, taking part in the Malmö Osteoporosis Prospective Risk Assessment (OPRA) study. Physical activity and muscle strength accounted for 1-6% of the variability in bone mass, whereas weight, and its closely associated variables lean mass and fat mass, to a much greater extent explained the bone mass variability. We found current body weight to be the variable with the most substantial influence on the total variability in bone mass (15-32% depending on skeletal site) in a forward stepwise regression model. Our findings suggest that in elderly women, the major fracture-preventive effect of physical activity is unlikely to be mediated through increased bone mass. Retaining or even increasing body weight is likely to be beneficial to the skeleton, but an excess body weight increase may have negative effects on health. Nevertheless, training in elderly women may have advantages by improving balance, co-ordination and mobility and therefore decreasing the risk of fractures.

  18. Leg blood flow is impaired during small muscle mass exercise in patients with COPD.

    PubMed

    Iepsen, U W; Munch, G W; Rugbjerg, M; Ryrsø, C K; Secher, N H; Hellsten, Y; Lange, P; Pedersen, B K; Thaning, P; Mortensen, S P

    2017-09-01

    Skeletal muscle blood flow is regulated to match the oxygen demand and dysregulation could contribute to exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). We measured leg hemodynamics and metabolites from vasoactive compounds in muscle interstitial fluid and plasma at rest, during one-legged knee-extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex-matched healthy controls were studied. During knee-extensor exercise (10 W), leg blood flow was lower in the patients compared with the controls (1.82 ± 0.11 vs. 2.36 ± 0.14 l/min, respectively; P < 0.05), which compromised leg oxygen delivery (372 ± 26 vs. 453 ± 32 ml O 2 /min, respectively; P < 0.05). At rest, plasma endothelin-1 (vasoconstrictor) was higher in the patients with COPD ( P < 0.05) and also tended to be higher during exercise ( P = 0.07), whereas the formation of interstitial prostacyclin (vasodilator) was only increased in the controls. There was no difference between groups in the nitrite/nitrate levels (vasodilator) in plasma or interstitial fluid during exercise. Moreover, patients and controls showed similar vasodilatory capacity in response to both endothelium-independent (SNP) and endothelium-dependent (ACh) stimulation. The results suggest that leg muscle blood flow is impaired during small muscle mass exercise in patients with COPD possibly due to impaired formation of prostacyclin and increased levels of endothelin-1. NEW & NOTEWORTHY This study demonstrates that chronic obstructive pulmonary disease (COPD) is associated with a reduced blood flow to skeletal muscle during small muscle mass exercise. In contrast to healthy individuals, interstitial prostacyclin levels did not increase during exercise and plasma endothelin-1 levels were higher in the patients with COPD. Copyright © 2017 the American Physiological

  19. Elevated Serum Pentosidine and Decreased Serum IGF-I Levels are Associated with Loss of Muscle Mass in Postmenopausal Women with Type 2 Diabetes Mellitus.

    PubMed

    Tanaka, K; Kanazawa, I; Sugimoto, T

    2016-03-01

    Advanced glycation end-products (AGEs) play important roles in the progression of diabetic complications. Although sarcopenia is recently recognized as another complication associated with diabetes mellitus, its mechanism still remains unclear. In this study, we investigated the relationship between serum levels of pentosidine, which is one of AGEs, and insulin-like growth factor-I (IGF-I) vs. skeletal muscle mass by whole body dual-energy x-ray absorptiometry in 133 postmenopausal women with type 2 diabetes. Relative skeletal muscle mass index (RSMI) was calculated by following formula; appendicular skeletal muscle mass divided by height in meters squared. Simple correlation analyses showed that serum pentosidine levels were significantly and negatively correlated with muscle mass of legs (r=-0.21, p=0.017) and RSMI (r=-0.18, p=0.022), and that IGF-I was significantly and positively correlated with muscle mass of arms and legs (r=0.23, p=0.008 and r=0.30, p=0.001, respectively) as well as RSMI (r=0.20, p=0.022). Moreover, after adjusting for age, duration of diabetes, serum creatinine, HbA1c, and IGF-I, pentosidine was significantly and negatively associated with RSMI (β=-0.27, p=0.018) and marginally with muscle mass of legs (β=-0.18, p=0.071). The associations between IGF-I and indices of muscle mass such as arms, legs and RSMI were still significant after additional adjustment for pentosidine (p=0.016, 0.019 and 0.021, respectively). These findings indicate that increased serum pentosidine and decreased IGF-I are independent risk factors for loss of muscle mass in postmenopausal women with type 2 diabetes. © Georg Thieme Verlag KG Stuttgart · New York.

  20. A novel intronic single nucleotide polymorphism in the myosin heavy polypeptide 4 gene is responsible for the mini-muscle phenotype characterized by major reduction in hind-limb muscle mass in mice.

    PubMed

    Kelly, Scott A; Bell, Timothy A; Selitsky, Sara R; Buus, Ryan J; Hua, Kunjie; Weinstock, George M; Garland, Theodore; Pardo-Manuel de Villena, Fernando; Pomp, Daniel

    2013-12-01

    Replicated artificial selection for high levels of voluntary wheel running in an outbred strain of mice favored an autosomal recessive allele whose primary phenotypic effect is a 50% reduction in hind-limb muscle mass. Within the High Runner (HR) lines of mice, the numerous pleiotropic effects (e.g., larger hearts, reduced total body mass and fat mass, longer hind-limb bones) of this hypothesized adaptive allele include functional characteristics that facilitate high levels of voluntary wheel running (e.g., doubling of mass-specific muscle aerobic capacity, increased fatigue resistance of isolated muscles, longer hind-limb bones). Previously, we created a backcross population suitable for mapping the responsible locus. We phenotypically characterized the population and mapped the Minimsc locus to a 2.6-Mb interval on MMU11, a region containing ∼100 known or predicted genes. Here, we present a novel strategy to identify the genetic variant causing the mini-muscle phenotype. Using high-density genotyping and whole-genome sequencing of key backcross individuals and HR mice with and without the mini-muscle mutation, from both recent and historical generations of the HR lines, we show that a SNP representing a C-to-T transition located in a 709-bp intron between exons 11 and 12 of the Myosin heavy polypeptide 4 (Myh4) skeletal muscle gene (position 67,244,850 on MMU11; assembly, December 2011, GRCm38/mm10; ENSMUSG00000057003) is responsible for the mini-muscle phenotype, Myh4(Minimsc). Using next-generation sequencing, our approach can be extended to identify causative mutations arising in mouse inbred lines and thus offers a great avenue to overcome one of the most challenging steps in quantitative genetics.

  1. Leucine partially protects muscle mass and function during bed rest in middle-aged adults1,2

    PubMed Central

    English, Kirk L; Mettler, Joni A; Ellison, Jennifer B; Mamerow, Madonna M; Arentson-Lantz, Emily; Pattarini, James M; Ploutz-Snyder, Robert; Sheffield-Moore, Melinda; Paddon-Jones, Douglas

    2016-01-01

    Background: Physical inactivity triggers a rapid loss of muscle mass and function in older adults. Middle-aged adults show few phenotypic signs of aging yet may be more susceptible to inactivity than younger adults. Objective: The aim was to determine whether leucine, a stimulator of translation initiation and skeletal muscle protein synthesis (MPS), can protect skeletal muscle health during bed rest. Design: We used a randomized, double-blind, placebo-controlled trial to assess changes in skeletal MPS, cellular signaling, body composition, and skeletal muscle function in middle-aged adults (n = 19; age ± SEM: 52 ± 1 y) in response to leucine supplementation (LEU group: 0.06 g ∙ kg−1 ∙ meal−1) or an alanine control (CON group) during 14 d of bed rest. Results: Bed rest decreased postabsorptive MPS by 30% ± 9% (CON group) and by 10% ± 10% (LEU group) (main effect for time, P < 0.05), but no differences between groups with respect to pre-post changes (group × time interactions) were detected for MPS or cell signaling. Leucine protected knee extensor peak torque (CON compared with LEU group: −15% ± 2% and −7% ± 3%; group × time interaction, P < 0.05) and endurance (CON compared with LEU: −14% ± 3% and −2% ± 4%; group × time interaction, P < 0.05), prevented an increase in body fat percentage (group × time interaction, P < 0.05), and reduced whole-body lean mass loss after 7 d (CON compared with LEU: −1.5 ± 0.3 and −0.8 ± 0.3 kg; group × time interaction, P < 0.05) but not 14 d (CON compared with LEU: −1.5 ± 0.3 and −1.0 ± 0.3 kg) of bed rest. Leucine also maintained muscle quality (peak torque/kg leg lean mass) after 14 d of bed-rest inactivity (CON compared with LEU: −9% ± 2% and +1% ± 3%; group × time interaction, P < 0.05). Conclusions: Bed rest has a profoundly negative effect on muscle metabolism, mass, and function in middle-aged adults. Leucine supplementation may partially protect muscle health during relatively

  2. Anti-myostatin antibody increases muscle mass and strength and improves insulin sensitivity in old mice.

    PubMed

    Camporez, João-Paulo G; Petersen, Max C; Abudukadier, Abulizi; Moreira, Gabriela V; Jurczak, Michael J; Friedman, Glenn; Haqq, Christopher M; Petersen, Kitt Falk; Shulman, Gerald I

    2016-02-23

    Sarcopenia, or skeletal muscle atrophy, is a debilitating comorbidity of many physiological and pathophysiological processes, including normal aging. There are no approved therapies for sarcopenia, but the antihypertrophic myokine myostatin is a potential therapeutic target. Here, we show that treatment of young and old mice with an anti-myostatin antibody (ATA 842) for 4 wk increased muscle mass and muscle strength in both groups. Furthermore, ATA 842 treatment also increased insulin-stimulated whole body glucose metabolism in old mice, which could be attributed to increased insulin-stimulated skeletal muscle glucose uptake as measured by a hyperinsulinemic-euglycemic clamp. Taken together, these studies provide support for pharmacological inhibition of myostatin as a potential therapeutic approach for age-related sarcopenia and metabolic disease.

  3. Influence of Altered Mass Loading on Testosterone Levels and Testicular Mass

    NASA Technical Reports Server (NTRS)

    Wang, Tommy J.; Ortiz, R. M.; Wade, C. E.; Hargens, Alan R. (Technical Monitor)

    1996-01-01

    Effects of altered load on testosterone levels and testicular mass in mammals are not well defined. Two separate studies (loading;centrifuged; +2G(sub z) and unloading;hindlimb suspension;HLS) were conducted to provide a better understanding of the effects of mass loading on testosterone levels and testicular mass. Daily urine samples were collected, and testicular mass measured at the end of the study. +2G(sub z): Sprague-Dawley rats (230-250 g) were centrifuged for 12 days at +2G(sub z): 8 centrifuged (EC) and 8 off centrifuge controls (OCC). EC had lower body mass, however relative testicular mass was greater. EC exhibited an increase in excreted testosterone levels between days 2 (T2) and 6 (T6), and returned to baseline at T9. HLS: To assess the effects of unloading Sprague-Dawley rats (125-150 g) were studied for 12 days: 10 suspended (Exp) and 10 ambulatory (Ctl). Exp had lower body mass during the study, with reduced absolute and relative testicular mass. Exp demonstrated lower excreted testosterone levels from T5-T12. Conclusions: Loading appears to stimulate anabolism, as opposed to unloading, as indicated by greater relative testicular mass and excreted testosterone levels. Reported changes in muscle mass during loading and unloading coincide with similar changes in excreted testosterone levels.

  4. Absolute Quantification of Rifampicin by MALDI Imaging Mass Spectrometry Using Multiple TOF/TOF Events in a Single Laser Shot

    NASA Astrophysics Data System (ADS)

    Prentice, Boone M.; Chumbley, Chad W.; Caprioli, Richard M.

    2017-01-01

    Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) allows for the visualization of molecular distributions within tissue sections. While providing excellent molecular specificity and spatial information, absolute quantification by MALDI IMS remains challenging. Especially in the low molecular weight region of the spectrum, analysis is complicated by matrix interferences and ionization suppression. Though tandem mass spectrometry (MS/MS) can be used to ensure chemical specificity and improve sensitivity by eliminating chemical noise, typical MALDI MS/MS modalities only scan for a single MS/MS event per laser shot. Herein, we describe TOF/TOF instrumentation that enables multiple fragmentation events to be performed in a single laser shot, allowing the intensity of the analyte to be referenced to the intensity of the internal standard in each laser shot while maintaining the benefits of MS/MS. This approach is illustrated by the quantitative analyses of rifampicin (RIF), an antibiotic used to treat tuberculosis, in pooled human plasma using rifapentine (RPT) as an internal standard. The results show greater than 4-fold improvements in relative standard deviation as well as improved coefficients of determination (R2) and accuracy (>93% quality controls, <9% relative errors). This technology is used as an imaging modality to measure absolute RIF concentrations in liver tissue from an animal dosed in vivo. Each microspot in the quantitative image measures the local RIF concentration in the tissue section, providing absolute pixel-to-pixel quantification from different tissue microenvironments. The average concentration determined by IMS is in agreement with the concentration determined by HPLC-MS/MS, showing a percent difference of 10.6%.

  5. An allometric analysis of the number of muscle spindles in mammalian skeletal muscles

    PubMed Central

    Banks, R W

    2006-01-01

    An allometric analysis of the number of muscle spindles in relation to muscle mass in mammalian (mouse, rat, guinea-pig, cat, human) skeletal muscles is presented. It is shown that the trend to increasing number as muscle mass increases follows an isometric (length) relationship between species, whereas within a species, at least for the only essentially complete sample (human), the number of spindles scales, on average, with the square root rather than the cube root of muscle mass. An attempt is made to reconcile these apparently discrepant relationships. Use of the widely accepted spindle density (number of spindles g−1 of muscle) as a measure of relative abundance of spindles in different muscles is shown to be grossly misleading. It is replaced with the residuals of the linear regression of ln spindle number against ln muscle mass. Significant differences in relative spindle abundance as measured by residuals were found between regional groups of muscles: the greatest abundance is in axial muscles, including those concerned with head position, whereas the least is in muscles of the shoulder girdle. No differences were found between large and small muscles operating in parallel, or between antigravity and non-antigravity muscles. For proximal vs. distal muscles, spindles were significantly less abundant in the hand than the arm, but there was no difference between the foot and the leg. PMID:16761976

  6. Muscle biopsies from human muscle diseases with myopathic pathology reveal common alterations in mitochondrial function.

    PubMed

    Sunitha, Balaraju; Gayathri, Narayanappa; Kumar, Manish; Keshava Prasad, Thottethodi Subrahmanya; Nalini, Atchayaram; Padmanabhan, Balasundaram; Srinivas Bharath, Muchukunte Mukunda

    2016-07-01

    Muscle diseases are clinically and genetically heterogeneous and manifest as dystrophic, inflammatory and myopathic pathologies, among others. Our previous study on the cardiotoxin mouse model of myodegeneration and inflammation linked muscle pathology with mitochondrial damage and oxidative stress. In this study, we investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies from muscle disease patients, represented by dysferlinopathy (dysfy) (dystrophic pathology; n = 43), polymyositis (PM) (inflammatory pathology; n = 24), and distal myopathy with rimmed vacuoles (DMRV) (distal myopathy; n = 31) were analyzed. Mitochondrial damage (ragged blue and COX-deficient fibers) was revealed in dysfy, PM, and DMRV cases by enzyme histochemistry (SDH and COX-SDH), electron microscopy (vacuolation and altered cristae) and biochemical assays (significantly increased ADP/ATP ratio). Proteomic analysis of muscle mitochondria from all three muscle diseases by isobaric tag for relative and absolute quantitation labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated down-regulation of electron transport chain (ETC) complex subunits, assembly factors and Krebs cycle enzymes. Interestingly, 80 of the under-expressed proteins were common among the three pathologies. Assay of ETC and Krebs cycle enzyme activities validated the MS data. Mitochondrial proteins from muscle pathologies also displayed higher tryptophan (Trp) oxidation and the same was corroborated in the cardiotoxin model. Molecular modeling predicted Trp oxidation to alter the local structure of mitochondrial proteins. Our data highlight mitochondrial alterations in muscle pathologies, represented by morphological changes, altered mitochondrial proteome and protein oxidation, thereby establishing the role of mitochondrial damage in human muscle diseases. We investigated whether human muscle diseases display mitochondrial changes. Muscle biopsies

  7. Poor physical function in elderly women in low-level aged care is related to muscle strength rather than to measures of sarcopenia

    PubMed Central

    Woods, Julie L; Iuliano-Burns, Sandra; King, Susannah J; Strauss, Boyd J; Walker, Karen Z

    2011-01-01

    Purpose: To determine the prevalence of sarcopenia and investigate relationships among body composition, muscle strength, and physical function in elderly women in low-level aged care. Subjects and methods: Sixty-three ambulatory women (mean age 86 years) participated in this cross-sectional study where body composition was determined by dual energy X-ray absorptiometry (DXA); ankle, knee, and hip strength by the Nicholas Manual Muscle Tester; and physical function by ‘timed up and go’ (TUG) and walking speed (WS) over 6 meters. Body composition data from a female reference group (n = 62, mean age 29 years) provided cut-off values for defining sarcopenia. Results: Elderly women had higher body mass index (P < 0.001), lower lean mass (P < 0.001), and higher fat mass (P < 0.01) than the young reference group. Only a small proportion (3.2%) had absolute sarcopenia (defined by appendicular skeletal muscle mass/height squared) whereas 37% had relative sarcopenia class II (defined by percentage skeletal muscle mass). Scores for TUG and WS indicated relatively poor physical function, yet these measures were not associated with muscle mass or indices of sarcopenia. In multivariate analysis, only hip abductor strength predicted both TUG and WS (both P = 0.01). Conclusion: Hip strength is a more important indicator of physical functioning than lean mass. Measurement of hip strength may therefore be a useful screening tool to detect those at risk of functional decline and requirement for additional care. Further longitudinal studies with a range of other strength measures are warranted. PMID:21472094

  8. ACTN3 genotype does not influence muscle power.

    PubMed

    Hanson, E D; Ludlow, A T; Sheaff, A K; Park, J; Roth, S M

    2010-11-01

    The R577X polymorphism within the ACTN3 gene has been associated with elite athletic performance, strength, power, fat free mass, and adaptations to strength training, though inconsistencies exist in the literature. The specific muscle power phenotypes most influenced by the polymorphism are uncertain. The purpose of this study was to examine the association between ACTN3 R577X genotype and muscle power phenotypes. Recreationally active young men and women (N=57) were selected to complete 2 muscle performance assessments, an isokinetic fatigue protocol at testing speeds of 180°  s (-1) and 250°  s (-1) and a 30 s Wingate test. Isokinetic torque and Wingate power significantly decreased over the duration of each test, but no differences in the rate of decline were observed among ACTN3 genotype groups. Similarly, no significant genotype differences were observed for isokinetic peak torque, Wingate absolute or relative peak power, or fatigue index. These results indicate that in recreationally active individuals the ACTN3 R577X polymorphism is not associated with muscle performance phenotypes, supporting recent findings that R577X may only be important for predicting performance in elite athletes. Our data also indicate that using this polymorphism for genetic screening in the lay population is scientifically questionable.

  9. Localized infusion of IGF-I results in skeletal muscle hypertrophy in rats

    NASA Technical Reports Server (NTRS)

    Adams, G. R.; McCue, S. A.

    1998-01-01

    Insulin-like growth factor I (IGF-I) peptide levels have been shown to increase in overloaded skeletal muscles (G. R. Adams and F. Haddad. J. Appl. Physiol. 81: 2509-2516, 1996). In that study, the increase in IGF-I was found to precede measurable increases in muscle protein and was correlated with an increase in muscle DNA content. The present study was undertaken to test the hypothesis that direct IGF-I infusion would result in an increase in muscle DNA as well as in various measurements of muscle size. Either 0.9% saline or nonsystemic doses of IGF-I were infused directly into a non-weight-bearing muscle of rats, the tibialis anterior (TA), via a fenestrated catheter attached to a subcutaneous miniosmotic pump. Saline infusion had no effect on the mass, protein content, or DNA content of TA muscles. Local IGF-I infusion had no effect on body or heart weight. The absolute weight of the infused TA muscles was approximately 9% greater (P < 0.05) than that of the contralateral TA muscles. IGF-I infusion resulted in significant increases in the total protein and DNA content of TA muscles (P < 0.05). As a result of these coordinated changes, the DNA-to-protein ratio of the hypertrophied TA was similar to that of the contralateral muscles. These results suggest that IGF-I may be acting to directly stimulate processes such as protein synthesis and satellite cell proliferation, which result in skeletal muscle hypertrophy.

  10. The bigger, the stronger? Insights from muscle architecture and nervous characteristics in obese adolescent girls.

    PubMed

    Garcia-Vicencio, S; Coudeyre, E; Kluka, V; Cardenoux, C; Jegu, A-G; Fourot, A-V; Ratel, S; Martin, V

    2016-02-01

    Young obese youth are generally stronger than lean youth. This has been linked to the loading effect of excess body mass, acting as a training stimulus comparable to strength training. Whether this triggers specific adaptations of the muscle architecture (MA) and voluntary activation (VA) that could account for the higher strength of obese subjects remains unknown. MA characteristics (that is, pennation angle (PA), fascicle length (FL) and muscle thickness (MT)) and muscle size (that is, anatomical cross-sectional area (ACSA)) of the knee extensor (KE) and plantar flexor (PF) muscles were evaluated in 12 obese and 12 non-obese adolescent girls (12-15 years). Maximal isometric torque and VA of the KE and PF muscles were also assessed. Results revealed higher PA (P<0.05), greater MT (P<0.001), ACSA (P<0.01), segmental lean mass (P<0.001) and VA (P<0.001) for KE and PF muscles in obese girls. Moreover, obese individuals produced a higher absolute torque than their lean counterparts on the KE (224.6±39.5 vs 135.7±32.7 N m, respectively; P<0.001) and PF muscles (73.3±16.5 vs 44.5±6.2 N m; P<0.001). Maximal voluntary contraction (MVC) was correlated to PA for the KE (r=0.46-0.57, P<0.05-0.01) and PF muscles (r=0.45-0.55, P<0.05-0.01). MVC was also correlated with VA (KE: r=0.44, P<0.05; PF: r=0.65, P<0.001) and segmental lean mass (KE: r=0.48, P<0.05; PF: r=0.57, P<0.01). This study highlighted favorable muscular and nervous adaptations to obesity that account for the higher strength of obese youth. The excess of body mass supported during daily activities could act as a chronic training stimulus responsible for these adaptations.

  11. Adults with initial metabolic syndrome have altered muscle deoxygenation during incremental exercise.

    PubMed

    Machado, Alessandro da Costa; Barbosa, Thales Coelho; Kluser Sales, Allan Robson; de Souza, Marcio Nogueira; da Nóbrega, Antonio Claudio Lucas; Silva, Bruno Moreira

    2017-02-01

    Reduced aerobic power is independently associated with metabolic syndrome (MetS) incidence and prevalence in adults. This study investigated whether muscle deoxygenation (proxy of microvascular O 2 extraction) during incremental exercise is altered in MetS and associated with reduced oxygen consumption ( V˙O 2peak ). Twelve men with initial MetS (no overt diseases and medication-naive; mean ± SD, age 38 ± 7 years) and 12 healthy controls (HCs) (34 ± 7 years) completed an incremental cycling test to exhaustion, in which pulmonary ventilation and gas exchange (metabolic analyzer), as well as vastus lateralis deoxygenation (near infrared spectroscopy), were measured. Subjects with MetS, in contrast to HCs, showed lower V˙O 2peak normalized to total lean mass, similar V˙O 2 response to exercise, and earlier break point (BP) in muscle deoxygenation. Consequently, deoxygenation slope from BP to peak exercise was greater. Furthermore, absolute V˙O 2peak was positively associated with BP in correlations adjusted for total lean mass. MetS, without overt diseases, altered kinetics of muscle deoxygenation during incremental exercise, particularly at high-intensity exercise. Therefore, the balance between utilization and delivery of O 2 within skeletal muscle is impaired early in MetS natural history, which may contribute to the reduction in aerobic power. © 2017 The Obesity Society.

  12. A Novel Intronic Single Nucleotide Polymorphism in the Myosin heavy polypeptide 4 Gene Is Responsible for the Mini-Muscle Phenotype Characterized by Major Reduction in Hind-Limb Muscle Mass in Mice

    PubMed Central

    Kelly, Scott A.; Bell, Timothy A.; Selitsky, Sara R.; Buus, Ryan J.; Hua, Kunjie; Weinstock, George M.; Garland, Theodore; Pardo-Manuel de Villena, Fernando; Pomp, Daniel

    2013-01-01

    Replicated artificial selection for high levels of voluntary wheel running in an outbred strain of mice favored an autosomal recessive allele whose primary phenotypic effect is a 50% reduction in hind-limb muscle mass. Within the High Runner (HR) lines of mice, the numerous pleiotropic effects (e.g., larger hearts, reduced total body mass and fat mass, longer hind-limb bones) of this hypothesized adaptive allele include functional characteristics that facilitate high levels of voluntary wheel running (e.g., doubling of mass-specific muscle aerobic capacity, increased fatigue resistance of isolated muscles, longer hind-limb bones). Previously, we created a backcross population suitable for mapping the responsible locus. We phenotypically characterized the population and mapped the Minimsc locus to a 2.6-Mb interval on MMU11, a region containing ∼100 known or predicted genes. Here, we present a novel strategy to identify the genetic variant causing the mini-muscle phenotype. Using high-density genotyping and whole-genome sequencing of key backcross individuals and HR mice with and without the mini-muscle mutation, from both recent and historical generations of the HR lines, we show that a SNP representing a C-to-T transition located in a 709-bp intron between exons 11 and 12 of the Myosin heavy polypeptide 4 (Myh4) skeletal muscle gene (position 67,244,850 on MMU11; assembly, December 2011, GRCm38/mm10; ENSMUSG00000057003) is responsible for the mini-muscle phenotype, Myh4Minimsc. Using next-generation sequencing, our approach can be extended to identify causative mutations arising in mouse inbred lines and thus offers a great avenue to overcome one of the most challenging steps in quantitative genetics. PMID:24056412

  13. Laser interferometry method for absolute measurement of the acceleration of gravity

    NASA Technical Reports Server (NTRS)

    Hudson, O. K.

    1971-01-01

    Gravimeter permits more accurate and precise absolute measurement of g without reference to Potsdam values as absolute standards. Device is basically Michelson laser beam interferometer in which one arm is mass fitted with corner cube reflector.

  14. Slow movement resistance training using body weight improves muscle mass in the elderly: A randomized controlled trial.

    PubMed

    Tsuzuku, S; Kajioka, T; Sakakibara, H; Shimaoka, K

    2018-04-01

    To examine the effect of a 12-week slow movement resistance training using body weight as a load (SRT-BW) on muscle mass, strength, and fat distribution in healthy elderly people. Fifty-three men and 35 women aged 70 years old or older without experience in resistance training participated, and they were randomly assigned to a SRT-BW group or control group. The control group did not receive any intervention, but participants in this group underwent a repeat measurement 12 weeks later. The SRT-BW program consisted of 3 different exercises (squat, tabletop push-up, and sit-up), which were designed to stimulate anterior major muscles. Initially, these exercises were performed by 2 sets of 10 repetitions, and subsequently, the number of repetitions was increased progressively by 2 repetitions every 4 weeks. Participants were instructed to perform each eccentric and concentric phase of movement slowly (spending 4 seconds on each movement), covering the full range of motion. We evaluated muscle mass, strength, and fat distribution at baseline and after 12 weeks of training. Changes over 12 weeks were significantly greater in the SRT-BW group than in the control group, with a decrease in waist circumference, hip circumference, and abdominal preperitoneal and subcutaneous fat thickness, and an increase in thigh muscle thickness, knee extension strength, and hip flexion strength. In conclusion, relatively short-term SRT-BW was effective in improving muscle mass, strength, and fat distribution in healthy elderly people. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Genetic variation in the human vitamin D receptor is associated with muscle strength, fat mass and body weight in Swedish women.

    PubMed

    Grundberg, Elin; Brändström, Helena; Ribom, Eva L; Ljunggren, Osten; Mallmin, Hans; Kindmark, Andreas

    2004-03-01

    Bone mineral density (BMD) is under strong genetic control and a number of candidate genes have been associated with BMD. Both muscle strength and body weight are considered to be important predictors of BMD but far less is known about the genes affecting muscle strength and fat mass. The purpose of this study was to investigate the poly adenosine (A) repeat and the BsmI SNP in the vitamin D receptor (VDR) in relation to muscle strength and body composition in healthy women. A population-based study of 175 healthy women aged 20-39 years was used. The polymorphic regions in the VDR gene (the poly A repeat and the BsmI SNP) were amplified by PCR. Body mass measurements (fat mass, lean mass, body weight and body mass index) and muscle strength (quadriceps, hamstring and grip strength) were evaluated. Individuals with shorter poly A repeat, ss and/or absence of the linked BsmI restriction site (BB) have higher hamstring strength (ss vs LL, P=0.02), body weight (ss vs LL, P=0.049) and fat mass (ss vs LL, P=0.04) compared with women with a longer poly A repeat (LL) and/or the presence of the linked BsmI restriction site (bb). Genetic variation in the VDR is correlated with muscle strength, fat mass and body weight in premenopausal women. Further functional studies on the poly A microsatellite are needed to elucidate whether this is the functionally relevant locus or if the polymorphism is in linkage disequilibrium with a functional variant in a closely situated gene further downstream of the VDR 3'UTR.

  16. Deep proteomics of mouse skeletal muscle enables quantitation of protein isoforms, metabolic pathways, and transcription factors.

    PubMed

    Deshmukh, Atul S; Murgia, Marta; Nagaraj, Nagarjuna; Treebak, Jonas T; Cox, Jürgen; Mann, Matthias

    2015-04-01

    Skeletal muscle constitutes 40% of individual body mass and plays vital roles in locomotion and whole-body metabolism. Proteomics of skeletal muscle is challenging because of highly abundant contractile proteins that interfere with detection of regulatory proteins. Using a state-of-the art MS workflow and a strategy to map identifications from the C2C12 cell line model to tissues, we identified a total of 10,218 proteins, including skeletal muscle specific transcription factors like myod1 and myogenin and circadian clock proteins. We obtain absolute abundances for proteins expressed in a muscle cell line and skeletal muscle, which should serve as a valuable resource. Quantitation of protein isoforms of glucose uptake signaling pathways and in glucose and lipid metabolic pathways provides a detailed metabolic map of the cell line compared with tissue. This revealed unexpectedly complex regulation of AMP-activated protein kinase and insulin signaling in muscle tissue at the level of enzyme isoforms. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. The PMA Catalogue: 420 million positions and absolute proper motions

    NASA Astrophysics Data System (ADS)

    Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

    2017-07-01

    We present a catalogue that contains about 420 million absolute proper motions of stars. It was derived from the combination of positions from Gaia DR1 and 2MASS, with a mean difference of epochs of about 15 yr. Most of the systematic zonal errors inherent in the 2MASS Catalogue were eliminated before deriving the absolute proper motions. The absolute calibration procedure (zero-pointing of the proper motions) was carried out using about 1.6 million positions of extragalactic sources. The mean formal error of the absolute calibration is less than 0.35 mas yr-1. The derived proper motions cover the whole celestial sphere without gaps for a range of stellar magnitudes from 8 to 21 mag. In the sky areas where the extragalactic sources are invisible (the avoidance zone), a dedicated procedure was used that transforms the relative proper motions into absolute ones. The rms error of proper motions depends on stellar magnitude and ranges from 2-5 mas yr-1 for stars with 10 mag < G < 17 mag to 5-10 mas yr-1 for faint ones. The present catalogue contains the Gaia DR1 positions of stars for the J2015 epoch. The system of the PMA proper motions does not depend on the systematic errors of the 2MASS positions, and in the range from 14 to 21 mag represents an independent realization of a quasi-inertial reference frame in the optical and near-infrared wavelength range. The Catalogue also contains stellar magnitudes taken from the Gaia DR1 and 2MASS catalogues. A comparison of the PMA proper motions of stars with similar data from certain recent catalogues has been undertaken.

  18. Transcatheter Arterial Embolization with a Mixture of Absolute Ethanol and Iodized Oil for Poorly Visualized Endophytic Renal Masses Prior to CT-Guided Percutaneous Cryoablation

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

    Michimoto, Kenkichi, E-mail: michikoo@jikei.ac.jp; Shimizu, Kanichiro; Kameoka, Yoshihiko

    PurposeTo retrospectively evaluate the feasibility of transcatheter arterial embolization (TAE) using a mixture of absolute ethanol and iodized oil to improve localization of endophytic renal masses on unenhanced computed tomography (CT) prior to CT-guided percutaneous cryoablation (PCA).Materials and MethodsOur institutional review board approved this retrospective study. From September 2011 to June 2015, 17 patients (mean age, 66.8 years) with stage T1a endophytic renal masses (mean diameter, 26.5 mm) underwent TAE using a mixture of absolute ethanol and iodized oil to improve visualization of small and endophytic renal masses on unenhanced CT prior to CT-guided PCA. TAE was considered successful that accumulated iodizedmore » oil depicted whole of the tumor edge on CT. PCA was considered successful when the iceball covered the entire tumor with over a 5 mm margin. Oncological and renal functional outcomes and complications were also evaluated.ResultsTAE was successfully performed in 16 of 17 endophytic tumors. The 16 tumors were performed under CT-guided PCA with their distinct visualization of localization and safe ablated margin. During the mean follow-up period of 15.4 ± 5.1 months, one patient developed local recurrence. Estimated glomerular filtration rate declined by 8 % with statistical significance (P = 0.01). There was no procedure-related significant complication.ConclusionTAE using a mixture of absolute ethanol and iodized oil to improve visualization of endophytic renal masses facilitated tumor localization on unenhanced CT, permitting depiction of the tumor edge as well as a safe margin for ablation during CT-guided PCA, with an acceptable decline in renal function.« less

  19. The effect of radical treatment and rehabilitation on muscle mass and strength: a randomized trial in stages I-III lung cancer patients.

    PubMed

    Salhi, B; Huysse, W; Van Maele, G; Surmont, V F; Derom, E; van Meerbeeck, J P

    2014-04-01

    Little is known about the impact of an oncological treatment on muscle mass and strength in patients with lung cancer and the impact of a subsequent rehabilitation program. This study investigates the effect of radical treatment and post-treatment pulmonary rehabilitation on muscle mass and strength in patients with lung cancer and the relationship between muscle mass and strength. Lung cancer patients, candidate for radical treatment, were randomly (2:1) allocated after radical treatment to either standard follow up (CON) or a 12-week rehabilitation training program (RT). Muscle mass was estimated by bioelectric impedance and CT-scan. Muscle strength was estimated by measuring quadriceps force (QF) with a hand held dynamometer. All variables were measured before (M1) and after radical treatment (M2), and at the earliest 12 weeks after randomization (M3). Data are presented as means with standard deviation. 45 lung cancer patients (age: 65 years (9)) participated in the study. At M2, both muscle cross sectional area (MCSA) and QF were significantly decreased (p<0.05). 28 patients were randomized. 13/18 RT and 9/10 CON patients ended the trial. At M3, RT-patients improved significantly their MCSA compared to CON-patients (ΔMCSA: 6 cm(2) (6) (p=0.003) vs. 1cm(2) (11) (p=0.8)). Muscle mass and strength: (1) are decreased at presentation in a substantial part of lung cancer patients; (2) are significantly negatively affected by radical treatment and (3) completely recover after a 12 week structured rehabilitation program, whereas a further decline was observed in CON-patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Age-related differences in lean mass, protein synthesis and skeletal muscle markers of proteolysis after bed rest and exercise rehabilitation.

    PubMed

    Tanner, Ruth E; Brunker, Lucille B; Agergaard, Jakob; Barrows, Katherine M; Briggs, Robert A; Kwon, Oh Sung; Young, Laura M; Hopkins, Paul N; Volpi, Elena; Marcus, Robin L; LaStayo, Paul C; Drummond, Micah J

    2015-09-15

    Bed rest-induced muscle loss and impaired muscle recovery may contribute to age-related sarcopenia. It is unknown if there are age-related differences in muscle mass and muscle anabolic and catabolic responses to bed rest. A secondary objective was to determine if rehabilitation could reverse bed rest responses. Nine older and fourteen young adults participated in a 5-day bed rest challenge (BED REST). This was followed by 8 weeks of high intensity resistance exercise (REHAB). Leg lean mass (via dual-energy X-ray absorptiometry; DXA) and strength were determined. Muscle biopsies were collected during a constant stable isotope infusion in the postabsorptive state and after essential amino acid (EAA) ingestion on three occasions: before (PRE), after bed rest and after rehabilitation. Samples were assessed for protein synthesis, mTORC1 signalling, REDD1/2 expression and molecular markers related to muscle proteolysis (MURF1, MAFBX, AMPKα, LC3II/I, Beclin1). We found that leg lean mass and strength decreased in older but not younger adults after bedrest (P < 0.05) and was restored after rehabilitation. EAA-induced mTORC1 signalling and protein synthesis increased before bed rest in both age groups (P < 0.05). Although both groups had blunted mTORC1 signalling, increased REDD2 and MURF1 mRNA after bedrest, only older adults had reduced EAA-induced protein synthesis rates and increased MAFBX mRNA, p-AMPKα and the LC3II/I ratio (P < 0.05). We conclude that older adults are more susceptible than young persons to muscle loss after short-term bed rest. This may be partially explained by a combined suppression of protein synthesis and a marginal increase in proteolytic markers. Finally, rehabilitation restored bed rest-induced deficits in lean mass and strength in older adults. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  1. Lifespan metabolic potential of the unicellular organisms expressed by Boltzmann constant, absolute temperature and proton mass

    NASA Astrophysics Data System (ADS)

    Atanasov, Atanas Todorov

    2016-12-01

    The unicellular organisms and phages are the first appeared fundamental living organisms on the Earth. The total metabolic energy (Els, J) of these organisms can be expressed by their lifespan metabolic potential (Als, J/kg) and body mass (M, kg): Els =Als M. In this study we found a different expression - by Boltzmann's constant (k, J/K), nucleon mass (mp+, kg) of protons (and neutrons), body mass (M, kg) of organism or mass (Ms) of biomolecules (proteins, nucleotides, polysaccharides and lipids) building organism, and the absolute temperature (T, K). The found equations are: Els= (M/mp+)kT for phages and Els=(Ms/mp+)kT for the unicellular organisms. From these equations the lifespan metabolic potential can be expressed as: Als=Els/M= (k/mp+)T for phages and Als=Els/M= (k/3.3mp+)T for unicellular organisms. The temperature-normated lifespan metabolic potential (Als/T, J/K.kg) is equals to the ratio between Boltzmann's constant and nucleon mass: Als/T=k/mp+ for phages and Als/T=k/3.3mp+ for unicellular organisms. The numerical value of the k/mp+ ratio is equals to 8.254×103 J/K.kg, and the numerical value of k/3.3mp+ ratio is equal to 2.497×103 J/K.kg. These values of temperature-normated lifespan metabolic potential could be considered fundamental for the unicellular organisms.

  2. Regulation of skeletal muscle oxidative capacity and muscle mass by SIRT3

    USDA-ARS?s Scientific Manuscript database

    We have previously reported that the expression of mitochondrial deacetylase SIRT3 is high in the slow oxidative muscle and that the expression of muscle SIRT3 level is increased by dietary restriction or exercise training. To explore the function of SIRT3 in skeletal muscle, we report here the esta...

  3. Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders.

    PubMed

    Elert, J; Kendall, S A; Larsson, B; Månsson, B; Gerdle, B

    2001-06-01

    To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

  4. Low muscle mass is associated with metabolic syndrome only in nonobese young adults: the Korea National Health and Nutrition Examination Survey 2008-2010.

    PubMed

    Kim, Byung Chul; Kim, Mee Kyoung; Han, Kyungdo; Lee, Sae-Young; Lee, Seung-Hwan; Ko, Seung-Hyun; Kwon, Hyuk-Sang; Merchant, Anwar T; Yim, Hyeon Woo; Lee, Won-Chul; Park, Yong Gyu; Park, Yong-Moon

    2015-12-01

    Little is known about the relationship between body composition and metabolic risk factors in young adults. We hypothesized that low muscle mass (LMM) is associated with metabolic syndrome (MetS) and its components in young adults and that the associations vary by obesity. A cross-sectional analysis was conducted using the Korea National Health and Nutrition Examination Survey data. In total, 5300 young adults aged 19 to 39 years were evaluated. Low muscle mass was defined as an appendicular skeletal muscle mass/weight less than 1 SD below the mean for each participant's corresponding sex and age group. Obesity was defined as a body mass index greater than or equal to 25 kg/m2. The prevalence of LMM was higher in obese than nonobese participants (37.6% vs. 9.6%). In the nonobese participants, the prevalence of MetS, high waist circumference, high triglycerides, and high blood pressure was significantly greater in the LMM group than in the high muscle mass group. In the nonobese group, compared with high muscle mass participants, those with LMM had odds ratios for MetS of 3.6 (95% confidence interval, 1.48-8.76; P < .001) and 3.6 (95% confidence interval, 1.48-8.71; P < .001) in men and women, respectively, after adjusting for confounding factors. However, no significant association of LMM with MetS or its components was found in obese participants. In conclusion, our results suggest that young adults with LMM may have a high risk of MetS, especially when they are nonobese. Interventions aimed at increasing muscle mass at younger ages may have the potential to reduce MetS. Published by Elsevier Inc.

  5. Deficiency of heat shock transcription factor 1 suppresses heat stress-associated increase in slow soleus muscle mass of mice.

    PubMed

    Ohno, Y; Egawa, T; Yokoyama, S; Nakai, A; Sugiura, T; Ohira, Y; Yoshioka, T; Goto, K

    2015-12-01

    Effects of heat shock transcription factor 1 (HSF1) deficiency on heat stress-associated increase in slow soleus muscle mass of mice were investigated. Both HSF1-null and wild-type mice were randomly assigned to control and heat-stressed groups. Mice in heat-stressed group were exposed to heat stress (41 °C for 60 min) in an incubator without anaesthesia. Significant increase in wet and dry weights, and protein content of soleus muscle in wild-type mice was observed seven days after the application of the heat stress. However, heat stress had no impact on soleus muscle mass in HSF1-null mice. Neither type of mice exhibited much effect of heat stress on HSF mRNA expression (HSF1, HSF2 and HSF4). On the other hand, heat stress upregulated heat shock proteins (HSPs) at the mRNA (HSP72) and protein (HSP72 and HSP110) levels in wild-type mice, but not in HSF1-null mice. The population of Pax7-positive nuclei relative to total myonuclei of soleus muscle in wild-type mice was significantly increased by heat stress, but not in HSF1-null mice. Furthermore, the absence of HSF1 gene suppressed heat stress-associated phosphorylation of Akt and p70 S6 kinase (p-p70S6K) in soleus muscle. Heat stress-associated increase in skeletal muscle mass may be induced by HSF1 and/or HSF1-mediated stress response that activates muscle satellite cells and Akt/p70S6K signalling pathway. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  6. Comparative proteomic analysis of the aging soleus and extensor digitorum longus rat muscles using TMT labeling and mass spectrometry

    PubMed Central

    Chaves, Daniela F. S.; Carvalho, Paulo C.; Lima, Diogo B.; Nicastro, Humberto; Lorenzetti, Fábio M.; Filho, Mário S.; Hirabara, Sandro M.; Alves, Paulo H. M.; Moresco, James J.; Yates, John R.; Lancha, Antonio H.

    2013-01-01

    Sarcopenia describes an age-related decline in skeletal muscle mass, strength, and function that ultimately impairs metabolism, leads to poor balance, frequent falling, limited mobility, and a reduction in quality of life. Here we investigate the pathogenesis of sarcopenia through a proteomic shotgun approach. Briefly, we employed tandem mass tags (TMT) to quantitate and compare the protein profiles obtained from young versus old rat slow-twitch type of muscle (soleus) and a fast-twitch type of muscle (extensor digitorum longus, EDL). Our results disclose 3452 and 1848 proteins identified from soleus and EDL muscles samples of which 78 and 174 were found to be differentially expressed, respectively. In general, most of the proteins were structural related, involved in energy metabolism, oxidative stress, detoxification, or transport. Aging affected soleus and EDL muscles differently and several proteins were regulated in opposite ways. For example, pyruvate kinase had its expression and activity different in both soleus and EDL muscles. We were able to verify with existing literature many of our differentially expressed proteins as candidate aging biomarkers, and most importantly, disclose several new candidate biomarkers such as the glioblastoma amplified sequence (GAS), zero beta-globin, and prolargin. PMID:24001182

  7. Comparative proteomic analysis of the aging soleus and extensor digitorum longus rat muscles using TMT labeling and mass spectrometry.

    PubMed

    Chaves, Daniela F S; Carvalho, Paulo C; Lima, Diogo B; Nicastro, Humberto; Lorenzeti, Fábio M; Siqueira-Filho, Mário; Hirabara, Sandro M; Alves, Paulo H M; Moresco, James J; Yates, John R; Lancha, Antonio H

    2013-10-04

    Sarcopenia describes an age-related decline in skeletal muscle mass, strength, and function that ultimately impairs metabolism and leads to poor balance, frequent falling, limited mobility, and a reduction in quality of life. Here we investigate the pathogenesis of sarcopenia through a proteomic shotgun approach. In brief, we employed tandem mass tags to quantitate and compare the protein profiles obtained from young versus old rat slow-twitch type of muscle (soleus) and a fast-twitch type of muscle (extensor digitorum longus, EDL). Our results disclose 3452 and 1848 proteins identified from soleus and EDL muscles samples, of which 78 and 174 were found to be differentially expressed, respectively. In general, most of the proteins were structural related and involved in energy metabolism, oxidative stress, detoxification, or transport. Aging affected soleus and EDL muscles differently, and several proteins were regulated in opposite ways. For example, pyruvate kinase had its expression and activity different in both soleus and EDL muscles. We were able to verify with existing literature many of our differentially expressed proteins as candidate aging biomarkers and, most importantly, disclose several new candidate biomarkers such as the glioblastoma amplified sequence, zero β-globin, and prolargin.

  8. Hypogonadal Men with Higher Body Mass Index have Higher Bone Density and Better Bone Quality but Reduced Muscle Density.

    PubMed

    Aguirre, Lina E; Colleluori, Georgia; Dorin, Richard; Robbins, David; Chen, Rui; Jiang, Bryan; Qualls, Clifford; Villareal, Dennis T; Armamento-Villareal, Reina

    2017-12-01

    Although hypogonadism is a risk factor for bone loss and fractures, the different etiopathophysiology and hormonal profile of classical and obesity-induced hypogonadism may lead to differences in musculoskeletal profile. This is a cross-sectional study of hypogonadal men between 40 and 74 years old. Our outcomes include: areal bone mineral density (aBMD) and body composition by dual-energy X-ray absorptiometry; volumetric BMD (vBMD) and soft tissue composition of the tibia by peripheral quantitative computed tomography. Fracture risk assessment tool (FRAX) scores were evaluated. Testosterone, estradiol, luteinizing hormone, follicle stimulating hormone, sex hormone-binding globulin, C-telopeptide, osteocalcin, and sclerostin were measured. We divided the population into subgroups of BMI: group 1: BMI < 30; group 2: BMI ≥30 to <35 and group 3: BMI ≥ 35 kg/m 2 . One-hundred five men were enrolled. Spine and hip aBMD, and total and trabecular vBMD at the 4% tibia significantly increased with increasing BMI. Cortical thickness (330.7 ± 53.2, 343.3 ± 35.4, and 358.7 ± 38.2 mm, p = 0.04; groups 1, 2 and 3, respectively) and cortical area (5.3 ± 0.7, 5.5 ± 0.6, and 5.7 ± 0.6 mm, p = 0.01; groups 1, 2 and 3, respectively) at 38% tibia increased with increasing BMI. While absolute lean mass increased with increasing BMI, % lean mass and muscle density (70.2 ± 5.0, 71.3 ± 6.4, and 67.1 ± 5.1 mg/cm 3 ; groups 1, 2 and 3, respectively) were lowest in group 3. Although severely obese hypogondal men have better BMD and bone quality, they have reduced muscle density, the significance of which remains to be determined.

  9. Lower circulating insulin-like growth factor-I is associated with better cognition in females with exceptional longevity without compromise to muscle mass and function.

    PubMed

    Perice, Leland; Barzilai, Nir; Verghese, Joe; Weiss, Erica F; Holtzer, Roee; Cohen, Pinchas; Milman, Sofiya

    2016-10-14

    Mutations that reduce somatotropic signaling result in improved lifespan and health-span in model organisms and humans. However, whether reduced circulating insulin-like growth factor-I (IGF-I) level is detrimental to cognitive and muscle function in older adults remains understudied. A cross-sectional analysis was performed in Ashkenazi Jews with exceptional longevity (age ≥95 years). Cognition was assessed using the Mini-Mental State Examination and muscle function with the chair rise test, grip-strength, and gait speed. Muscle mass was estimated using the skeletal muscle index. Serum IGF-I was measured with liquid chromatography mass spectrometry. In gender stratified age-adjusted logistic regression analysis, females with IGF-I levels in the first tertile had lower odds of being cognitively impaired compared to females with IGF-I levels within the upper two tertiles, OR (95% CI) 0.39 (0.19-0.82). The result remained significant after adjustment for multiple parameters. No significant association was identified in males between IGF-I and cognition. No relationship was found between IGF-I tertiles and muscle function and muscle mass in females or males. Lower circulating IGF-I is associated with better cognitive function in females with exceptional longevity, with no detriment to skeletal muscle mass and function.

  10. Noninvasive evaluation of muscle mass by ultrasonography of quadriceps femoris muscle in End-Stage Renal Disease patients on hemodialysis.

    PubMed

    Sabatino, Alice; Regolisti, Giuseppe; Delsante, Marco; Di Motta, Tommaso; Cantarelli, Chiara; Pioli, Sarah; Grassi, Giulia; Batini, Valentina; Gregorini, Mariacristina; Fiaccadori, Enrico

    2018-05-19

    Protein-Energy Wasting (PEW) is a pathological condition of renal patients with advanced Chronic Kidney Disease characterized by a progressive reduction of energy and protein assets. Nutritional status assessment, especially for what concerns muscle mass, is essential for both the identification of patients at risk for the development of PEW, as well as monitoring the effects of nutritional interventions. Ultrasound methods are easily applicable at the bedside for quantitative assessment of skeletal muscle. The present study was aimed at evaluating quadriceps rectus femoris thickness (QRFT) and quadriceps vastus intermedius thickness (QVIT) in patients on chronic hemodialysis. This was a prospective observational study. Three groups of adult patients were studied: young healthy subjects, well-nourished hospitalized patients with normal renal function, and End-Stage Renal Disease patients on hemodialysis (ESRD-HD). QRFT and QVIT were measured at two sites bilaterally (8 measures/patient) and were compared between groups, and also between subgroups of ESRD-HD patients stratified on the basis of conventional nutritional status parameters. We enrolled 35 healthy subjects, 30 hospitalized patients, and 121 ESRD-HD patients on hemodialysis. QRFT and QVIT of ESRD patients on hemodialysis were lower than those of both control groups (P < 0.001). After stratifying ESRD patients into subgroups based on nutritional variable cut-offs commonly used to define PEW in this clinical setting (BMI [≥ 23 vs <23 kg/m 2 ], albumin [≥3.8 vs <3.8 g/dL]) and malnutrition inflammation score (MIS) status (<6 vs ≥6), QRFT and QVIT of patients with worse nutritional status were significantly lower than those of well-nourished ESRD-HD patients (P value range: <0.001 to <0.05). Skeletal muscle ultrasound is a simple and easily applicable bedside technique in the dialysis units, and could represent an adequate tool for the identification of patients with reduced muscle mass. Copyright

  11. [Blood distribution in the human leg arteries during orthostasis: role of the hydrostatic factor and posturotonic straining of the anti-gravity muscles].

    PubMed

    Modin, A Iu

    2004-01-01

    Ultrasonic visualization and dopplerography were used to study volumetric blood flows along the femoral artery, deep artery of the thigh, and the popliteal and sural arteries in normal volunteers. Active standing test resulted in significant blood redistribution among the arteries with prioritized blood supply to predominantly anti-g muscles but not to predominantly locomotor muscles. Elimination of static loading on the anti-g muscles by weight removal (transfer of the body mass on the other leg) was conducive to the opposite effect, i.e. absolute and relative decreases in the intensity of blood flow along the sural artery and a relatively more marked blood redistribution toward the deep artery of the thigh.

  12. Higher Protein Intake Is Associated with Higher Lean Mass and Quadriceps Muscle Strength in Adult Men and Women.

    PubMed

    Sahni, Shivani; Mangano, Kelsey M; Hannan, Marian T; Kiel, Douglas P; McLean, Robert R

    2015-07-01

    The impact of dietary protein intake on lower extremity lean mass and strength in community-dwelling adult Americans is not fully understood. The objective was to determine the associations between total protein (TP), animal protein (AP), and plant protein (PP) intakes and lean mass of the legs and quadriceps muscle strength. We further examined whether the associations with quadriceps strength may be explained by lean mass of the legs. This cross-sectional study included men (n = 1166) and women (n = 1509) from the Framingham Offspring Cohort in Massachusetts. Protein intake in grams per day was measured in either 1995-1998 or 1998-2001. Leg lean mass and isometric quadriceps strength, both in kilograms, were measured in 1996-2001. Multilinear regression models estimated adjusted least squares means of each of the muscle measures by quartile categories of protein intake, adjusting for relevant confounders and covariates. Mean age was 59 ± 9 y (range: 29-86 y) and TP intake was 80 ± 27 g/d in men and 76 ± 26 g/d in women. In men and women, leg lean mass was higher in participants in the highest quartiles of TP and AP intake compared with those in the lowest quartiles of intake [least squares means (kg): TP-17.6 vs. 17.1 in men, P-trend: 0.005, and 11.7 vs. 11.4 in women, P-trend: 0.006; AP-17.6 vs. 17.1 in men, P-trend: 0.002, and 11.7 vs. 11.4 in women, P-trend: 0.003]. PP intake was not associated with lean mass in either sex. In men and women, quadriceps strength was higher in participants in the highest quartile of PP intake compared with those in the lowest quartile [least squares means (kg): 22.9 vs. 21.7 in men, P-trend: 0.01, and 19.0 vs. 18.2 in women, P-trend: 0.01]; this association was no longer significant after adjustment for fruit and vegetable intake (P-trend: 0.06 in men and 0.10 in women). Although no significant association was observed for AP intake in either sex, nonsignificant protective trends were observed for TP intake (P-trend: 0.08 in

  13. Parvalbumin Gene Transfer Impairs Skeletal Muscle Contractility in Old Mice

    PubMed Central

    Murphy, Kate T.; Ham, Daniel J.; Church, Jarrod E.; Naim, Timur; Trieu, Jennifer; Williams, David A.

    2012-01-01

    Abstract Sarcopenia is the progressive age-related loss of skeletal muscle mass associated with functional impairments that reduce mobility and quality of life. Overt muscle wasting with sarcopenia is usually preceded by a slowing of the rate of relaxation and a reduction in maximum force production. Parvalbumin (PV) is a cytosolic Ca2+ buffer thought to facilitate relaxation in muscle. We tested the hypothesis that restoration of PV levels in muscles of old mice would increase the magnitude and hasten relaxation of submaximal and maximal force responses. The tibialis anterior (TA) muscles of young (6 month), adult (13 month), and old (26 month) C57BL/6 mice received electroporation-assisted gene transfer of plasmid encoding PV or empty plasmid (pcDNA3.1). Contractile properties of TA muscles were assessed in situ 14 days after transfer. In old mice, muscles with increased PV expression had a 40% slower rate of tetanic force development (p<0.01), and maximum twitch and tetanic force were 22% and 16% lower than control values, respectively (p<0.05). Muscles with increased PV expression from old mice had an 18% lower maximum specific (normalized) force than controls, and absolute force was ∼26% lower at higher stimulation frequencies (150–300 Hz, p<0.05). In contrast, there was no effect of increased PV expression on TA muscle contractile properties in young and adult mice. The impairments in skeletal muscle function in old mice argue against PV overexpression as a therapeutic strategy for ameliorating aspects of contractile dysfunction with sarcopenia and help clarify directions for therapeutic interventions for age-related changes in skeletal muscle structure and function. PMID:22455364

  14. Muscle mass is associated with incident fracture in postmenopausal women: The OFELY study.

    PubMed

    Sornay-Rendu, E; Duboeuf, F; Boutroy, S; Chapurlat, R D

    2017-01-01

    The relationships between body composition and bone mineral density are well established but the contribution of body composition to the risk of fracture (Fx) has rarely been evaluated prospectively. We analyzed the risk of Fx by body composition in 595 postmenopausal women (mean age 66±8years) from a longitudinal cohort study (Os des Femmes de Lyon). We assessed the risk of the first incident fragility Fx according to body composition obtained from whole-body DXA: abdominal visceral (VFAT) and subcutaneous fat mass (SFAT), total body fat mass (FM), lean mass index (LMI) and appendicular skeletal muscle mass index (ASMI). During a median [IQ] follow-up of 13.1years [1.9], 138 women sustained a first incident Fx, including 85 women with a major osteoporotic Fx (MOP Fx: hip, clinical spine, humerus or wrist). After adjustment for age, women who sustained Fx had lower BMI (-4%, p=0.01), LMI (-6%, p=0.002) and ASMI (-3%, p=0.003), compared with women without Fx. After adjustment for age, prevalent Fx, physical activity, incident falls and FN BMD, each SD increase of baseline values of LMI and ASMI was associated with decreased Fx risk with adjusted hazard ratios of 0.76 for both of p≤0.02. Those associations were similar after accounting for the competing risk of death. VFAT and SFAT were associated with Fx risk in the multivariate model only for MOP Fx and the association did not persist after consideration of competing mortality. We conclude that lean mass and appendicular muscle mass indexes are associated with the risk of fracture in postmenopausal women independently of BMD and clinical risk factors. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Selection in action: dissecting the molecular underpinnings of the increasing muscle mass of Belgian Blue Cattle.

    PubMed

    Druet, Tom; Ahariz, Naima; Cambisano, Nadine; Tamma, Nico; Michaux, Charles; Coppieters, Wouter; Charlier, Carole; Georges, Michel

    2014-09-17

    Belgian Blue cattle are famous for their exceptional muscular development or "double-muscling". This defining feature emerged following the fixation of a loss-of-function variant in the myostatin gene in the eighties. Since then, sustained selection has further increased muscle mass of Belgian Blue animals to a comparable extent. In the present paper, we study the genetic determinants of this second wave of muscle growth. A scan for selective sweeps did not reveal the recent fixation of another allele with major effect on muscularity. However, a genome-wide association study identified two genome-wide significant and three suggestive quantitative trait loci (QTL) affecting specific muscle groups and jointly explaining 8-21% of the heritability. The top two QTL are caused by presumably recent mutations on unique haplotypes that have rapidly risen in frequency in the population. While one appears on its way to fixation, the ascent of the other is compromised as the likely underlying MRC2 mutation causes crooked tail syndrome in homozygotes. Genomic prediction models indicate that the residual additive variance is largely polygenic. Contrary to complex traits in humans which have a near-exclusive polygenic architecture, muscle mass in beef cattle (as other production traits under directional selection), appears to be controlled by (i) a handful of recent mutations with large effect that rapidly sweep through the population, and (ii) a large number of presumably older variants with very small effects that rise slowly in the population (polygenic adaptation).

  16. Preserving Healthy Muscle during Weight Loss123

    PubMed Central

    Cava, Edda; Yeat, Nai Chien; Mittendorfer, Bettina

    2017-01-01

    Weight loss is the cornerstone of therapy for people with obesity because it can ameliorate or completely resolve the metabolic risk factors for diabetes, coronary artery disease, and obesity-associated cancers. The potential health benefits of diet-induced weight loss are thought to be compromised by the weight-loss–associated loss of lean body mass, which could increase the risk of sarcopenia (low muscle mass and impaired muscle function). The objective of this review is to provide an overview of what is known about weight-loss–induced muscle loss and its implications for overall physical function (e.g., ability to lift items, walk, and climb stairs). The currently available data in the literature show the following: 1) compared with persons with normal weight, those with obesity have more muscle mass but poor muscle quality; 2) diet-induced weight loss reduces muscle mass without adversely affecting muscle strength; 3) weight loss improves global physical function, most likely because of reduced fat mass; 4) high protein intake helps preserve lean body and muscle mass during weight loss but does not improve muscle strength and could have adverse effects on metabolic function; 5) both endurance- and resistance-type exercise help preserve muscle mass during weight loss, and resistance-type exercise also improves muscle strength. We therefore conclude that weight-loss therapy, including a hypocaloric diet with adequate (but not excessive) protein intake and increased physical activity (particularly resistance-type exercise), should be promoted to maintain muscle mass and improve muscle strength and physical function in persons with obesity. PMID:28507015

  17. Sonic hedgehog acts cell-autonomously on muscle precursor cells to generate limb muscle diversity

    PubMed Central

    Anderson, Claire; Williams, Victoria C.; Moyon, Benjamin; Daubas, Philippe; Tajbakhsh, Shahragim; Buckingham, Margaret E.; Shiroishi, Toshihiko; Hughes, Simon M.; Borycki, Anne-Gaëlle

    2012-01-01

    How muscle diversity is generated in the vertebrate body is poorly understood. In the limb, dorsal and ventral muscle masses constitute the first myogenic diversification, as each gives rise to distinct muscles. Myogenesis initiates after muscle precursor cells (MPCs) have migrated from the somites to the limb bud and populated the prospective muscle masses. Here, we show that Sonic hedgehog (Shh) from the zone of polarizing activity (ZPA) drives myogenesis specifically within the ventral muscle mass. Shh directly induces ventral MPCs to initiate Myf5 transcription and myogenesis through essential Gli-binding sites located in the Myf5 limb enhancer. In the absence of Shh signaling, myogenesis is delayed, MPCs fail to migrate distally, and ventral paw muscles fail to form. Thus, Shh production in the limb ZPA is essential for the spatiotemporal control of myogenesis and coordinates muscle and skeletal development by acting directly to regulate the formation of specific ventral muscles. PMID:22987640

  18. Role of muscle mass and mode of contraction in circulatory responses to exercise

    NASA Technical Reports Server (NTRS)

    Lewis, S. F.; Snell, P. G.; Pettinger, W. A.; Blomqvist, C. G.; Taylor, W. F.; Hamra, M.; Graham, R. M.

    1985-01-01

    The roles of the mode of contraction (dynamic or static) and active muscle mass in determining the cardiovascular response to exercise has been investigated experimentally in six normal men. Exercise consisted of static handgrip and dynamic handgrip exercise, and static and dynamic knee extension for a period of six minutes. Observed increases in mean arterial pressure after exercise were similar for each mode of contraction, but larger for knee extension than handgrip exercise. Cardiac output increased more for dynamic than for static exercise and for each mode more for knee exercise than for handgrip exercise. Systemic resistance was found to be lower for dynamic than for static exercise, and to decrease from resisting levels by about one third during dynamic knee extension. It is shown that the magnitude of cardiovascular response is related to active muscle mass, but is independent of the contraction mode. Equalization of cardiovascular response was achieved by proportionately larger increases in cardiac output during dynamic exercise. The complete experimental results are given in a table.

  19. Comparison of lateral abdominal muscle thickness between weightlifters and matched controls.

    PubMed

    Sitilertpisan, Patraporn; Pirunsan, Ubon; Puangmali, Aatit; Ratanapinunchai, Jonjin; Kiatwattanacharoen, Suchart; Neamin, Hudsaleark; Laskin, James J

    2011-11-01

    To compare lateral abdominal muscle thickness between weightlifters and matched controls. A case control study design. University laboratory. 16 female Thai national weightlifters and 16 matched controls participated in this study. Ultrasound imaging with a 12-MHz linear array was used to measure the resting thickness of transversus abdominis (TrA), internal oblique (IO) and total thickness (Total) of lateral abdominal muscle (LAM) on the right side of abdominal wall. The absolute muscle thickness and the relative contribution of each muscle to the total thickness were determined. Weightlifters had significantly thicker absolute TrA and IO muscles than matched controls (p < 0.01). Further, the relative thickness of the IO was significantly greater in weightlifters than matched controls (p < 0.05). The findings of this study suggest that routine Olympic style weight training among female weightlifters appears to result in preferential hypertrophy or adaptation of the IO muscle. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Muscle Measures and Nutritional Status at Hospital Admission Predict Survival and Independent Living of Older Patients - the EMPOWER Study.

    PubMed

    Verlaan, S; Van Ancum, J M; Pierik, V D; Van Wijngaarden, J P; Scheerman, K; Meskers, C G M; Maier, A B

    2017-01-01

    Older adults with sarcopenia and malnutrition are at risk for co-morbidities, hospitalization, institutionalization, and mortality. In case of hospitalization, risks may be further increased, especially in case of suboptimal dietary intake. The aim of our study was to assess whether muscle mass, muscle strength, functional performance, and nutritional status at hospital admission were associated with survival and independent living among older patients three months after discharge. The EMPOWER study was an observational, prospective and longitudinal inception cohort of patients older than 70 years admitted to the VU University Medical Centre in Amsterdam, the Netherlands. Patients were assessed for demographic and clinical characteristics, measurements of muscle mass (by bioelectrical impedance analysis), handgrip strength (by dynamometry), functional performance (self-reported ability to walk), and screened for risk of malnutrition (by SNAQ). Three months after hospital discharge, survival and living situation were assessed by a follow-up telephone interview. The majority of the 378 patients enrolled were living independently at the time of hospitalization (90%) and three months post-discharge (83%). Fifty-two patients died in the period from hospital admission to three months after discharge (survival rate 86%). Higher absolute muscle mass measures and not being malnourished at admission were significantly associated with the likelihood of survival. Handgrip strength and self-reported ability to walk were positively associated with a higher chance of living independently three months after discharge, but not with survival. Older patients with greater muscle mass and without malnutrition at hospital admission had a higher survival rate, while measures of muscle strength and functional performance were predictive for living independently three months after hospital discharge. Different components of muscle health relate to different relevant outcomes and therefore

  1. Loss of muscle mass: Current developments in cachexia and sarcopenia focused on biomarkers and treatment.

    PubMed

    Drescher, Cathleen; Konishi, Masaaki; Ebner, Nicole; Springer, Jochen

    2016-01-01

    Loss of muscle mass arises from an imbalance of protein synthesis and protein degradation. Potential triggers of muscle wasting and function are immobilization, loss of appetite, dystrophies and chronic diseases as well as aging. All these conditions lead to increased morbidity and mortality in patients, which makes it a timely matter to find new biomarkers to get a fast clinical diagnosis and to develop new therapies. This mini-review covers current developments in the field of biomarkers and drugs on cachexia and sarcopenia. Here, we reported about promising markers, e.g. tartrate-resistant acid phosphatase 5a (TRACP5a), and novel substances like Epigallocatechin-3-gallate (EGCg). In summary, the progress to combat muscle wasting is in full swing and perhaps diagnosis of muscle atrophy and of course patient treatments could be soon supported by improved and more helpful strategies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Building Muscles, Keeping Muscles: Protein Turnover During Space Flight

    NASA Technical Reports Server (NTRS)

    Ferrando, Arny; Bloomberg, Jacob; Lee, Angie (Technical Monitor)

    2002-01-01

    As we age we lose muscle mass and strength. The problem is a matter of use it or lose it and more - a fact to which any active senior can attest. An imbalance in the natural cycle of protein turnover may be a contributing factor to decreased muscle mass. But the answer is not so simple, since aging is associated with changes in hormones, activity levels, nutrition, and often, disease. The human body constantly uses amino acids to build muscle protein, which then breaks down and must be replaced. When protein turnover gets out of balance, so that more protein breaks down than the body can replace, the result is muscle loss. This is not just the bane of aging, however. Severely burned people may have difficulty building new muscle long after the burned skin has been repaired. Answers to why we lose muscle mass and strength - and how doctors can fix it - may come from space. Astronauts usually eat a well-balanced diet and maintain an exercise routine to stay in top health. During long-duration flight, they exercise regularly to reduce the muscle loss that results from being in a near-weightless environment. Despite these precautions, astronauts lose muscle mass and strength during most missions. They quickly recover after returning to Earth - this is a temporary condition in an otherwise healthy population. Members of the STS-107 crew are participating in a study of the effects of space flight, hormone levels, and stress on protein turnover. When we are under stress, the body responds with a change in hormone levels. Researchers hypothesize that this stress-induced change in hormones along with the near-weightlessness might result in the body synthesizing less muscle protein, causing muscles to lose their strength and size. Astronauts, who must perform numerous duties in a confined and unusual environment, experience some stress during their flight, making them excellent candidates for testing the researchers' hypothesis.

  3. Absolute quantification methods in tissue near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Matcher, Steven J.; Kirkpatrick, Peter J.; Nahid, K.; Cope, Mark; Delpy, David T.

    1995-05-01

    Recent work aimed at providing an absolute measurement of tissue haemoglobin saturation and a new instrument development, the spatially resolved spectrometer (SRS), are discussed. The theoretical basis of operation of this device and its hardware implementation are described and the results of validation studies on tissue simulating phantoms are presented as are preliminary measurements on human volunteers and observations on patients undergoing neurosurgery. In its present form the instrument appears to produce absolute haemoglobin saturation values for resting human skeletal muscle and the normally perfused human head which are rather low based on physiological expectations. However, we obtained a tight correlation between the saturation values measured by the SRS instrument and those obtained from blood-gas analysis of samples drawn from a jugular bulb catheter in one neurosurgery subject during clamping of the right carotid arteries.

  4. Irisin and FNDC5: effects of 12-week strength training, and relations to muscle phenotype and body mass composition in untrained women.

    PubMed

    Ellefsen, S; Vikmoen, O; Slettaløkken, G; Whist, J E; Nygaard, H; Hollan, I; Rauk, I; Vegge, G; Strand, T A; Raastad, T; Rønnestad, B R

    2014-09-01

    To investigate the effects of strength training on abundances of irisin-related biomarkers in skeletal muscle and blood of untrained young women, and their associations with body mass composition, muscle phenotype and levels of thyroid hormones. Eighteen untrained women performed 12 weeks of progressive whole-body heavy strength training, with measurement of strength, body composition, expression of irisin-related genes (FNDC5 and PGC1α) in two different skeletal muscles, and levels of serum-irisin and -thyroid hormones, before and after the training intervention. The strength training intervention did not result in changes in serum-irisin or muscle FNDC5 expression, despite considerable effects on strength, lean body mass (LBM) and skeletal muscle phenotype. Our data indicate that training affects irisin biology in a LBM-dependent manner. However, no association was found between steady-state serum-irisin or training-associated changes in serum-irisin and alterations in body composition. FNDC5 expression was higher in m.Biceps brachii than in m.Vastus lateralis, with individual expression levels being closely correlated, suggesting a systemic mode of transcriptional regulation. In pre-biopsies, FNDC5 expression was correlated with proportions of aerobic muscle fibers, a relationship that disappeared in post-biopsies. No association was found between serum-thyroid hormones and FNDC5 expression or serum-irisin. No evidence was found for an effect of strength training on irisin biology in untrained women, though indications were found for a complex interrelationship between irisin, body mass composition and muscle phenotype. FNDC5 expression was closely associated with muscle fiber composition in untrained muscle.

  5. Quantitative analysis of veterinary drugs in bovine muscle and milk by liquid chromatography quadrupole time-of-flight mass spectrometry.

    PubMed

    Saito-Shida, Shizuka; Sakai, Takatoshi; Nemoto, Satoru; Akiyama, Hiroshi

    2017-07-01

    A simple and reliable multiresidue method for quantitative determination of veterinary drugs in bovine muscle and milk using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was developed. Critical MS parameters such as capillary voltage, cone voltage, collision energy, desolvation gas temperature and extraction mass window were carefully optimised to obtain the best possible sensitivity. Analytical samples were prepared using extraction with acetonitrile and hexane in the presence of anhydrous sodium sulphate and acetic acid, followed by ODS cartridge clean-up. The developed method was validated for 82 veterinary drugs in bovine muscle and milk at spike levels of 0.01 and 0.1 mg kg - 1 . With the exception of cefoperazone and phenoxymethylpenicillin, all these compounds exhibited sufficient signal intensity at 0.01 μg ml -1 (equivalent to 0.01 mg kg - 1 ), indicating the high sensitivity of the developed method. For most targets, the determined accuracies were within 70-120%, with repeatability and reproducibility being below 20% at both levels. Except for sulfathiazole in bovine muscle, no interfering peaks at target compound retention times were detected in the blank extract, indicating that the developed method is highly selective. The absence of sulfathiazole in bovine muscle was confirmed by simultaneous acquisition at low and high collision energies to afford exact masses of molecular adduct and fragment ions. Satisfactory linearity was observed for all compounds, with matrix effects being negligible for most targets in bovine muscle and milk at both spike levels. Overall, the results suggest that the developed LC-QTOF-MS method is suitable for routine regulatory-purpose analysis of veterinary drugs in bovine muscle and milk.

  6. Usefulness of circuit training at home for improving bone mass and muscle mass while losing fat mass in undergraduate female students.

    PubMed

    Takahata, Yoko

    2018-05-09

    The purpose of this study was to determine whether or not circuit training at home affects the calcaneus quantitative ultrasound status as well as other indices of body composition among undergraduate female students. Forty-one adolescents were recruited (18.5 ± 0.6 years old). The stiffness index of the calcaneus, broadband ultrasound attenuation of the calcaneus, speed of sound of the calcaneus, and body frame index. This was a three-month intervention study, so the measurements were conducted at baseline, 2 months later, and 3 months later while the subjects underwent circuit training at home. The subjects were divided into two groups: namely, the exercising group and non-exercising group. In the exercising group, broadband ultrasound attenuation of the calcaneus was higher 2 months later (p = 0.033) as well as 3 months later (p = 0.036), and the speed of sound of the calcaneus was higher 3 months later (p = 0.018). In addition, the muscle mass was strongly positively correlated with the calcaneus QUS-SOS (p = 0.004), while the body fat percentage was a strongly negatively correlated with the calcaneus QUS-BUA (p = 0.043). In the non-exercising group, the stiffness index of the calcaneus was higher 2 months later (p = 0.002) as well as 3 months later (p = 0.002). Furthermore, the body percentage was strongly positively correlated with the calcaneus QUS-SI (p = 0.009). These findings suggest that the calcaneus quantitative ultrasound status and muscle mass while losing fat mass may be improved by means of a simple exercise regimen within a short period among undergraduate female students.

  7. Ratio of Dietary n-6/n-3 Polyunsaturated Fatty Acids Independently Related to Muscle Mass Decline in Hemodialysis Patients.

    PubMed

    Wong, Te-Chih; Chen, Yu-Tong; Wu, Pei-Yu; Chen, Tzen-Wen; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Yang, Shwu-Huey

    2015-01-01

    n-3 polyunsaturated fatty acids (PUFAs) might be useful nutritional strategy for treating patients with sarcopenia. We evaluated the effect of the intake of dietary n-3 PUFAs on the skeletal muscle mass (SMM), appendicular skeletal muscle mass (ASM), and its determinants in patients receiving standard hemodialysis (HD) treatment for the management of end stage renal disease. In this cross-sectional study, data of 111 HD patients were analyzed. Anthropometric and bioelectrical impedance measurements used to estimate the muscle mass were performed the day of dialysis immediately after the dialysis session. Routine laboratory and 3-day dietary data were also collected. The cutoff value of adequate intake (AI) for both n-3 PUFAs and alpha-linolenic acid (ALA) was 1.6 g/day and 1.1 g/day for men and women, respectively. The mean age, mean dietary n-3 PUFAs intake, ALA intake, ratio of n-6/n-3 PUFAs intake, SMM, and ASM of patients were 61.4 ± 10.4 years, 2.0 ± 1.3 g/day, 1.5 ± 1.0 g/day, 9.5 ± 6.7 g/day, 23.9 ± 5.5 kg, and 17.5 ± 4.5 kg, respectively. A higher SMM and ASM significantly observed in patients who achieved an AI of n-3 PUFAs. Similar trends appeared to be observed among those patients who achieved the AI of ALA, but the difference was not significantly, except for ASM (P = 0.047). No relevant differences in demographics, laboratory and nutritional parameters were observed, regardless of whether the patients achieved an AI of n-3 PUFAs. Multivariate analysis showed that the BMI and equilibrated Kt/V were independent determinants of the muscle mass. Moreover, the ratio of n-6/n-3 PUFAs was an independent risk determinant of reduced ASM in HD patients. Patients with an AI of n-3 PUFAs had better total-body SMM and ASM. A higher dietary ratio of n-6/n-3 PUFAs seemed to be associated with a reduced muscle mass in HD patients.

  8. Integrative Analyses of miRNA-mRNA Interactions Reveal let-7b, miR-128 and MAPK Pathway Involvement in Muscle Mass Loss in Sex-Linked Dwarf Chickens

    PubMed Central

    Luo, Wen; Lin, Shumao; Li, Guihuan; Nie, Qinghua; Zhang, Xiquan

    2016-01-01

    The sex-linked dwarf (SLD) chicken is an ideal model system for understanding growth hormone (GH)-action and growth hormone receptor (GHR) function because of its recessive mutation in the GHR gene. Skeletal muscle mass is reduced in the SLD chicken with a smaller muscle fiber diameter. Our previous study has presented the mRNA and miRNA expression profiles of the SLD chicken and normal chicken between embryo day 14 and seven weeks of age. However, the molecular mechanism of GHR-deficient induced muscle mass loss is still unclear, and the key molecules and pathways underlying the GHR-deficient induced muscle mass loss also remain to be illustrated. Here, by functional network analysis of the differentially expressed miRNAs and mRNAs between the SLD and normal chickens, we revealed that let-7b, miR-128 and the MAPK pathway might play key roles in the GHR-deficient induced muscle mass loss, and that the reduced cell division and growth are potential cellular processes during the SLD chicken skeletal muscle development. Additionally, we also found some genes and miRNAs involved in chicken skeletal muscle development, through the MAPK, PI3K-Akt, Wnt and Insulin signaling pathways. This study provides new insights into the molecular mechanism underlying muscle mass loss in the SLD chickens, and some regulatory networks that are crucial for chicken skeletal muscle development. PMID:26927061

  9. Strong Relation between Muscle Mass Determined by D3-creatine Dilution, Physical Performance and Incidence of Falls and Mobility Limitations in a Prospective Cohort of Older Men.

    PubMed

    Cawthon, Peggy M; Orwoll, Eric S; Peters, Katherine E; Ensrud, Kristine E; Cauley, Jane A; Kado, Deborah M; Stefanick, Marcia L; Shikany, James M; Strotmeyer, Elsa S; Glynn, Nancy W; Caserotti, Paolo; Shankaran, Mahalakshmi; Hellerstein, Marc; Cummings, Steven R; Evans, William J

    2018-06-12

    Direct assessment of skeletal muscle mass in older adults is clinically challenging. Relationships between lean mass and late-life outcomes have been inconsistent. The D3-creatine dilution method provides a direct assessment of muscle mass. Muscle mass was assessed by D3-creatine (D3Cr) dilution in 1,382 men (mean age, 84.2 yrs). Participants completed the Short Physical Performance Battery (SPPB); usual walking speed (6 meters); and DXA lean mass. Men self-reported mobility limitations (difficulty walking 2-3 blocks or climbing 10 steps); recurrent falls (2+); and serious injurious falls in the subsequent year. Across quartiles of D3Cr muscle mass/body mass, multivariate linear models calculated means for SPPB and gait speed; multivariate logistic models calculated odds ratios for incident mobility limitations or falls. Compared to men in the highest quartile, those in the lowest quartile of D3Cr muscle mass/body mass had slower gait speed (Q1: 1.04 vs Q4: 1.17 m/s); lower SPPB (Q1: 8.4 vs Q4: 10.4 points); greater likelihood of incident serious injurious falls (OR Q1 vs Q4: 2.49, 95% CI: 1.37, 4.54); prevalent mobility limitation (OR Q1 vs Q4,: 6.1, 95%CI: 3.7, 10.3) and incident mobility limitation (OR Q1 vs Q4: 2.15 95% CI: 1.42, 3.26); p for trend <.001 for all. Results for incident recurrent falls were in the similar direction (p=0.156). DXA lean mass had weaker associations with the outcomes. Unlike DXA lean mass, low D3Cr muscle mass/body mass is strongly related to physical performance, mobility and incident injurious falls in older me.

  10. Low muscle mass and risk of type 2 diabetes in middle-aged and older adults: findings from the KoGES.

    PubMed

    Son, Jang Won; Lee, Seong Su; Kim, Sung Rae; Yoo, Soon Jib; Cha, Bong Yun; Son, Ho Young; Cho, Nam H

    2017-05-01

    Asians have a propensity to develop type 2 diabetes with a lower BMI than Western populations. This discrepancy may be due to differences in body fat and muscle mass for a given BMI. However, unlike adiposity, it is unclear whether muscle mass affects the risk of type 2 diabetes in Asian populations. We conducted a 2-yearly prospective assessment of 6895 participants who were free of diabetes at the baseline examination as part of the Korean Genome Epidemiology Study. The muscle mass index (MMI) was defined as the weight-adjusted appendicular skeletal muscle mass. Using Cox regression models, we evaluated the association between MMI and the risk of developing type 2 diabetes across sex-specific tertiles of MMI. Low muscle mass was defined as the sex-specific lowest tertile of MMI. Main covariates included age, sex, urban or rural residence, family history of diabetes, hypertension, smoking status, education level, monthly income, physical activity, alcohol consumption and diet. In addition, body fat mass, waist circumference and BMI were controlled as categorical variables. Obesity was defined as a BMI of ≥25 kg/m 2 or a waist circumference of ≥90 cm for men and ≥85 cm for women. During a median follow-up of 9.06 years, 1336 participants developed type 2 diabetes. At baseline, the mean age was 52.1 years and the mean BMI was 24.4 kg/m 2 . The mean MMI for men and women was 32.1% and 26.0%, respectively. There was an inverse association between MMI and the risk of type 2 diabetes. Multivariate-adjusted HRs for the risk of developing type 2 diabetes were 2.05 (95% CI 1.73, 2.43), 1.39 (95% CI 1.17, 1.66) and 1.0 from the lowest to highest sex-specific MMI tertile, with an HR of 1.35 (95% CI 1.26, 1.45) per SD decline in MMI. Further adjustments for fat mass, waist circumference and BMI as categorical variables did not modify the relationship (each p < 0.01). In BMI-stratified analyses, the population-attributable fraction of the lowest tertile of MMI

  11. Reduced bone mass and muscle strength in male 5α-reductase type 1 inactivated mice.

    PubMed

    Windahl, Sara H; Andersson, Niklas; Börjesson, Anna E; Swanson, Charlotte; Svensson, Johan; Movérare-Skrtic, Sofia; Sjögren, Klara; Shao, Ruijin; Lagerquist, Marie K; Ohlsson, Claes

    2011-01-01

    Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1⁻/⁻ mice. Four-month-old male Srd5a1⁻/⁻ mice had reduced trabecular bone mineral density (-36%, p<0.05) and cortical bone mineral content (-15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1⁻/⁻ mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1⁻/⁻ mice. Male Srd5a1⁻/⁻ mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1⁻/⁻ mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1⁻/⁻ mice, is an indirect effect mediated by elevated circulating androgen levels.

  12. Reduced Bone Mass and Muscle Strength in Male 5α-Reductase Type 1 Inactivated Mice

    PubMed Central

    Windahl, Sara H.; Andersson, Niklas; Börjesson, Anna E.; Swanson, Charlotte; Svensson, Johan; Movérare-Skrtic, Sofia; Sjögren, Klara; Shao, Ruijin; Lagerquist, Marie K.; Ohlsson, Claes

    2011-01-01

    Androgens are important regulators of bone mass but the relative importance of testosterone (T) versus dihydrotestosterone (DHT) for the activation of the androgen receptor (AR) in bone is unknown. 5α-reductase is responsible for the irreversible conversion of T to the more potent AR activator DHT. There are two well established isoenzymes of 5α-reductase (type 1 and type 2), encoded by separate genes (Srd5a1 and Srd5a2). 5α-reductase type 2 is predominantly expressed in male reproductive tissues whereas 5α-reductase type 1 is highly expressed in liver and moderately expressed in several other tissues including bone. The aim of the present study was to investigate the role of 5α-reductase type 1 for bone mass using Srd5a1−/− mice. Four-month-old male Srd5a1 −/− mice had reduced trabecular bone mineral density (−36%, p<0.05) and cortical bone mineral content (−15%, p<0.05) but unchanged serum androgen levels compared with wild type (WT) mice. The cortical bone dimensions were reduced in the male Srd5a1 −/− mice as a result of a reduced cortical periosteal circumference compared with WT mice. T treatment increased the cortical periosteal circumference (p<0.05) in orchidectomized WT mice but not in orchidectomized Srd5a1 −/− mice. Male Srd5a1 −/− mice demonstrated a reduced forelimb muscle grip strength compared with WT mice (p<0.05). Female Srd5a1 −/− mice had slightly increased cortical bone mass associated with elevated circulating levels of androgens. In conclusion, 5α-reductase type 1 inactivated male mice have reduced bone mass and forelimb muscle grip strength and we propose that these effects are due to lack of 5α-reductase type 1 expression in bone and muscle. In contrast, the increased cortical bone mass in female Srd5a1 −/− mice, is an indirect effect mediated by elevated circulating androgen levels. PMID:21731732

  13. Strength Exercise Improves Muscle Mass and Hepatic Insulin Sensitivity in Obese Youth

    PubMed Central

    van der Heijden, Gert-Jan; Wang, Zhiyue J.; Chu, Zili; Toffolo, Gianna; Manesso, Erica; Sauer, Pieter J.J.; Sunehag, Agneta L.

    2010-01-01

    Introduction Data are limited on the metabolic effects of resistance exercise (strength training) in adolescents. Purpose The objective of this study was to determine whether a controlled resistance exercise program without dietary intervention or weight loss, reduces body fat accumulation, increases lean body mass, and improves insulin sensitivity and glucose metabolism in sedentary obese Hispanic adolescents. Methods Twelve obese adolescents (15.5±0.5y; 35.3 ±0.8kg/m2;40.8±1.5% body fat), completed a 12 wk resistance exercise program (2×1h/wk, exercising all major muscle groups). At baseline and completion of the program, body composition was measured by DXA, abdominal fat distribution by Magnetic Resonance Imaging, hepatic and intramyocellular fat by Magnetic Resonance Spectroscopy, peripheral insulin sensitivity by the Stable Labeled IV Glucose Tolerance Test and hepatic insulin sensitivity by the Hepatic Insulin Sensitivity Index =1000/(GPR*fasting insulin). Glucose production rate (GPR), gluconeogenesis and glycogenolysis were quantified using Stable Isotope-Gas Chromatography/Mass Spectrometry techniques. Results All participants were normoglycemic. The exercise program resulted in significant strength gain in both upper and lower body muscle groups. Body weight increased from 97.0±3.8 to 99.6±4.2 kg (p<0.01). The major part (~80%) was accounted for by increased lean body mass (55.7±2.8 to 57.9±3.0 kg; p≤0.01).Total, visceral, hepatic and intramyocellular fat content remained unchanged. Hepatic insulin sensitivity increased by 24±9% (p<0.05), while peripheral insulin sensitivity did not change significantly. GPR decreased by 8±1% (p<0.01) due to a 12±5% decrease in glycogenolysis (p<0.05). Conclusion We conclude that a controlled resistance exercise program without weight loss increases strength and lean body mass, improves hepatic insulin sensitivity and decreases GPR without affecting total fat mass or visceral, hepatic and intramyocellular

  14. Absolute gravity measurements in California

    NASA Astrophysics Data System (ADS)

    Zumberge, M. A.; Sasagawa, G.; Kappus, M.

    1986-08-01

    An absolute gravity meter that determines the local gravitational acceleration by timing a freely falling mass with a laser interferometer has been constructed. The instrument has made measurements at 11 sites in California, four in Nevada, and one in France. The uncertainty in the results is typically 10 microgal. Repeated measurements have been made at several of the sites; only one shows a substantial change in gravity.

  15. Age-dependent increase in oxidative stress in gastrocnemius muscle with unloading

    PubMed Central

    Siu, Parco M.; Pistilli, Emidio E.; Alway, Stephen E.

    2008-01-01

    Oxidative stress increases during unloading in muscle from young adult rats. The present study examined the markers of oxidative stress and antioxidant enzyme gene and protein expressions in medial gastrocnemius muscles of aged and young adult (30 and 6 mo of age) Fischer 344 × Brown Norway rats after 14 days of hindlimb suspension. Medial gastrocnemius muscle weight was decreased by ∼30% in young adult and aged rats following suspension. When muscle weight was normalized to animal body weight, it was reduced by 12% and 22% in young adult and aged rats, respectively, after suspension. Comparisons between young adult and aged control animals demonstrated a 25% and 51% decline in muscle mass when expressed as absolute muscle weight and muscle weight normalized to the animal body weight, respectively. H2O2 content was elevated by 43% while Mn superoxide dismutase (MnSOD) protein content was reduced by 28% in suspended muscles compared with control muscles exclusively in the aged animals. Suspended muscles had greater content of malondialdehyde (MDA)/4-hydroxyalkenals (4-HAE) (29% and 58% increase in young adult and aged rats, respectively), nitrotyrosine (76% and 65% increase in young adult and aged rats, respectively), and catalase activity (69% and 43% increase in young adult and aged rats, respectively) relative to control muscles. Changes in oxidative stress markers MDA/4-HAE, H2O2, and MnSOD protein contents in response to hindlimb unloading occurred in an age-dependent manner. These findings are consistent with the hypotheses that oxidative stress has a role in mediating disuse-induced and sarcopenia-associated muscle losses. Our data suggest that aging may predispose skeletal muscle to increased levels of oxidative stress both at rest and during unloading. PMID:18801960

  16. Vitamin D and muscle function

    USDA-ARS?s Scientific Manuscript database

    Muscle weakness is a hallmark of severe vitamin D deficiency, but the effect of milder vitamin D deficiency or insufficiency on muscle mass and performance and risk of falling is uncertain. In this presentation, I review the evidence that vitamin D influences muscle mass and performance, balance, an...

  17. Noninvasive analysis of human neck muscle function

    NASA Technical Reports Server (NTRS)

    Conley, M. S.; Meyer, R. A.; Bloomberg, J. J.; Feeback, D. L.; Dudley, G. A.

    1995-01-01

    STUDY DESIGN. Muscle use evoked by exercise was determined by quantifying shifts in signal relaxation times of T2-weighted magnetic resonance images. Images were collected at rest and after exercise at each of two intensities (moderate and intense) for each of four head movements: 1) extension, 2) flexion, 3) rotation, and 4) lateral flexion. OBJECTIVE. This study examined the intensity and pattern of neck muscle use evoked by various movements of the head. The results will help elucidate the pathophysiology, and thus methods for treating disorders of the cervical musculoskeletal system. SUMMARY OF BACKGROUND DATA. Exercise-induced contrast shifts in T2 has been shown to indicate muscle use during the activity. The noninvasive nature of magnetic resonance imaging appears to make it an ideal approach for studying the function of the complex neuromuscular system of the neck. METHODS. The extent of T2 increase was examined to gauge how intensely nine different neck muscles or muscle pairs were used in seven subjects. The absolute and relative cross-sectional area of muscle showing a shift in signal relaxation was assessed to infer the pattern of use among and within individual neck muscles or muscle pairs. RESULTS. Signal relaxation increased with exercise intensity for each head movement. The absolute and relative cross-sectional area of muscle showing a shift in signal relaxation also increased with exercise load. Neck muscles or muscle pairs extensively used to perform each head movement were: extension--semispinalis capitis and cervicis and splenius capitis; flexion--sternocleidomastoid and longus capitis and colli; rotation--splenius capitis, levator scapulae, scalenus, semispinalis capitis ipsilateral to the rotation, and sternocleidomastoid contralateral; and lateral flexion--sternocleidomastoid CONCLUSION. The results of this study, in part, agree with the purported functions of neck muscles derived from anatomic location. This also was true for the few

  18. Absolute photoionization cross-section of the methyl radical.

    PubMed

    Taatjes, Craig A; Osborn, David L; Selby, Talitha M; Meloni, Giovanni; Fan, Haiyan; Pratt, Stephen T

    2008-10-02

    The absolute photoionization cross-section of the methyl radical has been measured using two completely independent methods. The CH3 photoionization cross-section was determined relative to that of acetone and methyl vinyl ketone at photon energies of 10.2 and 11.0 eV by using a pulsed laser-photolysis/time-resolved synchrotron photoionization mass spectrometry method. The time-resolved depletion of the acetone or methyl vinyl ketone precursor and the production of methyl radicals following 193 nm photolysis are monitored simultaneously by using time-resolved synchrotron photoionization mass spectrometry. Comparison of the initial methyl signal with the decrease in precursor signal, in combination with previously measured absolute photoionization cross-sections of the precursors, yields the absolute photoionization cross-section of the methyl radical; sigma(CH3)(10.2 eV) = (5.7 +/- 0.9) x 10(-18) cm(2) and sigma(CH3)(11.0 eV) = (6.0 +/- 2.0) x 10(-18) cm(2). The photoionization cross-section for vinyl radical determined by photolysis of methyl vinyl ketone is in good agreement with previous measurements. The methyl radical photoionization cross-section was also independently measured relative to that of the iodine atom by comparison of ionization signals from CH3 and I fragments following 266 nm photolysis of methyl iodide in a molecular-beam ion-imaging apparatus. These measurements gave a cross-section of (5.4 +/- 2.0) x 10(-18) cm(2) at 10.460 eV, (5.5 +/- 2.0) x 10(-18) cm(2) at 10.466 eV, and (4.9 +/- 2.0) x 10(-18) cm(2) at 10.471 eV. The measurements allow relative photoionization efficiency spectra of methyl radical to be placed on an absolute scale and will facilitate quantitative measurements of methyl concentrations by photoionization mass spectrometry.

  19. Low muscle mass and sarcopenia: common and predictive of osteopenia in inflammatory bowel disease.

    PubMed

    Bryant, R V; Ooi, S; Schultz, C G; Goess, C; Grafton, R; Hughes, J; Lim, A; Bartholomeusz, F D; Andrews, J M

    2015-05-01

    Body composition is poorly studied in inflammatory bowel disease (IBD). Sarcopenia describes a loss of muscle mass and strength. To assess the prevalence of low lean mass (LM), sarcopenia and associated morbidity in an adult IBD cohort. Cross-sectional data were gathered on pre-menopausal 18- to 50-year-old patients with IBD. Whole-body dual-energy X-ray absorptiometry, anthropometric assessment and grip strength were performed. Low LM was defined as ≥1 s.d. below the population mean for appendicular skeletal muscle index [ASMI (kg)/height (m)²], and sarcopenia as both ASMI and grip strength ≥1 s.d. below population mean. Multivariate regression analyses were performed. Of 137 participants (median age 31 years, BMI 24.8 kg/m(2) ), 56% were male and 69% had Crohn's disease (CD). Low LM and sarcopenia were observed in 21% and 12% of patients, respectively, and osteopenia/osteoporosis in 38% of patients (mean lumbar spine t-score -0.3 ± s.d. 1.1). Grip strength predicted low LM and sarcopenia better than did body mass index (BMI) (OR 4.8 vs. OR 0.7 for low-LM, P < 0.05 both). Normal BMI was falsely reassuring in 72% and 76% of patients with low ASMI and sarcopenia, respectively. Low LM and sarcopenia (OR = 3.6, P = 0.03; OR = 6.3, P = 0.02; respectively), but not BMI nor fat mass, predicted osteopenia/osteoporosis. Low lean mass and sarcopenia are common in patients with IBD, and important to recognise as they predict osteopenia/osteoporosis. Grip strength testing should be incorporated into routine clinical practice to detect low lean mass deficits, which may go unrecognised using BMI alone. © 2015 John Wiley & Sons Ltd.

  20. Human Muscle Protein Synthetic Responses during Weight-Bearing and Non-Weight-Bearing Exercise: A Comparative Study of Exercise Modes and Recovery Nutrition.

    PubMed

    Pasiakos, Stefan M; McClung, Holly L; Margolis, Lee M; Murphy, Nancy E; Lin, Gregory G; Hydren, Jay R; Young, Andrew J

    2015-01-01

    Effects of conventional endurance (CE) exercise and essential amino acid (EAA) supplementation on protein turnover are well described. Protein turnover responses to weighted endurance exercise (i.e., load carriage, LC) and EAA may differ from CE, because the mechanical forces and contractile properties of LC and CE likely differ. This study examined muscle protein synthesis (MPS) and whole-body protein turnover in response to LC and CE, with and without EAA supplementation, using stable isotope amino acid tracer infusions. Forty adults (mean ± SD, 22 ± 4 y, 80 ± 10 kg, VO 2peak 4.0 ± 0.5 L ∙ min(-1)) were randomly assigned to perform 90 min, absolute intensity-matched (2.2 ± 0.1 VO2 L ∙ m(-1)) LC (performed on a treadmill wearing a vest equal to 30% of individual body mass, mean ± SD load carried 24 ± 3 kg) or CE (cycle ergometry performed at the same absolute VO2 as LC) exercise, during which EAA (10 g EAA, 3.6 g leucine) or control (CON, non-nutritive) drinks were consumed. Mixed-muscle and myofibrillar MPS were higher during exercise for LC than CE (mode main effect, P < 0.05), independent of dietary treatment. EAA enhanced mixed-muscle and sarcoplasmic MPS during exercise, regardless of mode (drink main effect, P < 0.05). Mixed-muscle and sarcoplasmic MPS were higher in recovery for LC than CE (mode main effect, P < 0.05). No other differences or interactions (mode x drink) were observed. However, EAA attenuated whole-body protein breakdown, increased amino acid oxidation, and enhanced net protein balance in recovery compared to CON, regardless of exercise mode (P < 0.05). These data show that, although whole-body protein turnover responses to absolute VO2-matched LC and CE are the same, LC elicited a greater muscle protein synthetic response than CE.

  1. The effect of protein intake and resistance training on muscle mass in acutely ill old medical patients - A randomized controlled trial.

    PubMed

    Buhl, Sussi F; Andersen, Aino L; Andersen, Jens R; Andersen, Ove; Jensen, Jens-Erik B; Rasmussen, Anne Mette L; Pedersen, Mette M; Damkjær, Lars; Gilkes, Hanne; Petersen, Janne

    2016-02-01

    Stress metabolism is associated with accelerated loss of muscle that has large consequences for the old medical patient. The aim of this study was to investigate if an intervention combining protein and resistance training was more effective in counteracting loss of muscle than standard care. Secondary outcomes were changes in muscle strength, functional ability and body weight. 29 acutely admitted old (>65 years) patients were randomly assigned to the intervention (n = 14) or to standard care (n = 15). The Intervention Group received 1.7 g protein/kg/day during admission and a daily protein supplement (18.8 g protein) and resistance training 3 times per week the 12 weeks following discharge. Muscle mass was assessed by Dual-energy X-ray Absorptiometry. Muscle strength was assessed by Hand Grip Strength and Chair Stand Test. Functional ability was assessed by the de Morton Mobility Index, the Functional Recovery Score and the New Mobility Score. Changes in outcomes from time of admission to three-months after discharge were analysed by linear regression analysis. The intention-to-treat analysis showed no significant effect of the intervention on lean mass (unadjusted: β-coefficient = -1.28 P = 0.32, adjusted for gender: β-coefficient = -0.02 P = 0.99, adjusted for baseline lean mass: β-coefficient = -0.31 P = 0.80). The de Morton Mobility Index significantly increased in the Control Group (β-coefficient = -11.43 CI: 0.72-22.13, P = 0.04). No other differences were found. No significant effect on muscle mass was observed in this group of acutely ill old medical patients. High compliance was achieved with the dietary intervention, but resistance training was challenging. Clinical trials identifier NCT02077491. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  2. Normal Weight but Low Muscle Mass and Abdominally Obese: Implications for the Cardiometabolic Risk Profile in Chronic Obstructive Pulmonary Disease.

    PubMed

    Beijers, Rosanne J H C G; van de Bool, Coby; van den Borst, Bram; Franssen, Frits M E; Wouters, Emiel F M; Schols, Annemie M W J

    2017-06-01

    It is well established that low muscle mass affects physical performance in chronic obstructive pulmonary disease (COPD). We hypothesize that combined low muscle mass and abdominal obesity may also adversely influence the cardiometabolic risk profile in COPD, even in those with normal weight. The cardiometabolic risk profile and the responsiveness to 4 months high-intensity exercise training was assessed in normal-weight patients with COPD with low muscle mass stratified by abdominal obesity. This is a cross-sectional study including 81 clinically stable patients with COPD (age 62.5 ± 8.2 years; 50.6% males; forced expiratory volume in 1 second 55.1 ± 19.5 percentage predicted) with fat-free mass index <25th percentile eligible for outpatient pulmonary rehabilitation. Body composition, blood biomarkers, blood pressure, physical activity level, dietary intake, and physical performance were assessed at baseline and in a subgroup after 4 months of exercise training. Mean body mass index was 22.7 ± 2.7 kg/m 2 , and 75% of patients had abdominal obesity. Abdominally obese patients had higher glucose, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), branched chain amino acids and a higher prevalence of metabolic syndrome compared with those without abdominal obesity. Exercise training improved cycling endurance time and quadriceps strength, but did not yield a clinically meaningful improvement of the cardiometabolic risk profile. Triglycerides showed a significant decrease, while the HOMA-IR increased. Abdominal obesity is highly prevalent in normal-weight patients with COPD with low muscle mass who showed an increased cardiometabolic risk compared with patients without abdominal obesity. This cardiometabolic risk profile was not altered after 4 months of exercise training. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

  3. Hormonal and lifestyle determinants of appendicular skeletal muscle mass in men: the MINOS study.

    PubMed

    Szulc, Pawel; Duboeuf, François; Marchand, François; Delmas, Pierre D

    2004-08-01

    Aging-related sarcopenia is characterized by a loss of muscle mass and strength and increased fatigability. However, studies of its determinants in elderly men are scarce. We investigated risk factors for sarcopenia in a large cohort of men. We analyzed 845 men aged 45-85 y who belonged to the MINOS cohort. Lifestyle factors (physical activity, tobacco smoking, alcohol intake, caffeine intake) were evaluated by using a standardized questionnaire. Appendicular skeletal muscle mass (ASM) was estimated by using dual-energy X-ray absorptiometry. The relative appendicular skeletal muscle mass index (RASM) was calculated as ASM/body height(2.3). Apparent free testosterone concentration (AFTC) and free testosterone index (FTI) were calculated on the basis of concentrations of total testosterone and sex hormone-binding globulin. RASM decreased with age (r = -0.29, P < 0.0001). Current smokers had lower RASM than did subjects who never smoked (-3.2%; P < 0.003). RASM increased with the intensity of physical activity at work (P for trend < 0.001). Men who participated in regular exercise during leisure time had 2.2% higher RASM than did those who did not (P < 0.03). Men whose values for AFTC, FTI, or 25-hydroxycholecalciferol [25(OH)D] were >2 SDs below the mean for young men had significantly lower RASM than did men with higher values. Men with sarcopenia, defined as the lowest quartile of RASM in the studied cohort (<6.32 kg/m(2.3)), were significantly older than men with normal RASM, weighed significantly less, smoked more, and spent significantly less time on leisure-time activities. Sarcopenic men also had lower values for testosterone, AFTC, FTI, and 25(OH)D. In elderly men, low physical activity, tobacco smoking, thinness, low testosterone (AFTC and FTI), and decreased 25(OH)D concentrations are risk factors for sarcopenia.

  4. Experiment K-6-21. Effect of microgravity on 1) metabolic enzymes of type 1 and type 2 muscle fibers and on 2) metabolic enzymes, neutransmitter amino acids, and neurotransmitter associated enzymes in motor and somatosensory cerebral cortex. Part 1: Metabolic enzymes of individual muscle fibers; part 2: metabolic enzymes of hippocampus and spinal cord

    NASA Technical Reports Server (NTRS)

    Lowry, O.; Mcdougal, D., Jr.; Nemeth, Patti M.; Maggie, M.-Y. Chi; Pusateri, M.; Carter, J.; Manchester, J.; Norris, Beverly; Krasnov, I.

    1990-01-01

    The individual fibers of any individual muscle vary greatly in enzyme composition, a fact which is obscured when enzyme levels of a whole muscle are measured. The purpose of this study was therefore to assess the changes due to weightless on the enzyme patterns composed by the individual fibers within the flight muscles. In spite of the limitation in numbers of muscles examined, it is apparent that: (1) that the size of individual fibers (i.e., their dry weight) was reduced about a third, (2) that this loss in dry mass was accompanied by changes in the eight enzymes studied, and (3) that these changes were different for the two muscles, and different for the two enzyme groups. In the soleus muscle the absolute amounts of the three enzymes of oxidative metabolism decreased about in proportion to the dry weight loss, so that their concentration in the atrophic fibers was almost unchanged. In contrast, there was little loss among the four enzymes of glycogenolysis - glycolysis so that their concentrations were substantially increased in the atrophic fibers. In the TA muscle, these seven enzymes were affected in just the opposite direction. There appeared to be no absolute loss among the oxidative enzymes, whereas the glycogenolytic enzymes were reduced by nearly half, so that the concentrations of the first metabolic group were increased within the atrophic fibers and the concentrations of the second group were only marginally decreased. The behavior of hexokinase was exceptional in that it did not decrease in absolute terms in either type of muscle and probably increased as much as 50 percent in soleus. Thus, their was a large increase in concentration of this enzyme in the atrophied fibers of both muscles. Another clear-cut finding was the large increase in the range of activities of the glycolytic enzymes among individual fibers of TA muscles. This was due to the emergence of TA fibers with activities for enzymes of this group extending down to levels as low as

  5. Effects of passive muscle stiffness measured by Shear Wave Elastography, muscle thickness, and body mass index on athletic performance in adolescent female basketball players.

    PubMed

    Akkoc, Orkun; Caliskan, Emine; Bayramoglu, Zuhal

    2018-05-02

    Athletic performance in basketball comprises the contributions of anaerobic and aerobic performance. The aim was to investigate the effects of passive muscle stiffness, using shear wave elastography (SWE), as well as muscle thickness, and body mass index (BMI), on both aerobic and anaerobic performances in adolescent female basketball players.Material and methods: Anaerobic and aerobic (VO2max) performance was assessed using the vertical jump and shuttle run tests, respectively, in 24 volunteer adolescent female basketball players. Passive muscle stiffness of the rectus femoris (RF), gastrocnemius medialis (GM), gastrocnemius lateralis (GL) and soleus muscles were measured by SWE, and the thickness of each muscle was assessed by gray scale ultrasound. The BMI of each participant was also calculated. The relationship between vertical jump and VO2max values, and those of muscle stiffness, thickness, and BMI were investigated via Pearson's correlation and multivariate linear regression analysis. No significant correlation was observed between muscle stiffness and VO2max or vertical jump (p>0.05). There was significant negative correlation between GL thickness and VO2max (p=0.026), and soleus thickness and VO2max (p=0.046). There was also a significant negative correlation between BMI and VO2max (p=0.001). Conclusions: This preliminary work can be a reference for future research. Although our article indicates that passive muscle stiffness measured by SWE is not directly related to athletic performance, future comprehensive studies should be performed in order to illuminate the complex nature of muscles. The  maintenance of lower muscle thickness and optimal BMI may be associated with better aerobic performance.

  6. Rat supraspinatus muscle atrophy after tendon detachment.

    PubMed

    Barton, Elisabeth R; Gimbel, Jonathan A; Williams, Gerald R; Soslowsky, Louis J

    2005-03-01

    Rotator cuff tears are one of the most common tendon disorders found in the healthy population. Tendon tears not only affect the biomechanical properties of the tendon, but can also lead to debilitation of the muscles attached to the damaged tendons. The changes that occur in the muscle after tendon detachment are not well understood. A rat rotator cuff model was utilized to determine the time course of changes that occur in the supraspinatus muscle after tendon detachment. It was hypothesized that the lack of load on the supraspinatus muscle would cause a significant decrease in muscle mass and a conversion of muscle fiber properties toward those of fast fiber types. Tendons were detached at the insertion on the humerus without repair. Muscle mass, morphology and fiber properties were measured at one, two, four, eight, and 16 weeks after detachment. Tendon detachment resulted in a rapid loss of muscle mass, an increase in the proportion of fast muscle fibers, and an increase in the fibrotic content of the muscle bed, concomitant with the appearance of adhesions of the tendon to surrounding surfaces. At 16 weeks post-detachment, muscle mass and the fiber properties in the deep muscle layers returned to normal levels. However, the fiber shifts observed in the superficial layers persisted throughout the experiment. These results suggest that load returned to the muscle via adhesions to surrounding surfaces, which may be sufficient to reverse changes in muscle mass.

  7. Development of the Muscle Appearance Satisfaction Scale: a self-report measure for the assessment of muscle dysmorphia symptoms.

    PubMed

    Mayville, Stephen B; Williamson, Donald A; White, Marney A; Netemeyer, Richard G; Drab, Danae L

    2002-12-01

    Muscle dysmorphia has recently been described as a variant of body dysmorphic disorder that involves an intense preoccupation with one's perceived lack of muscle size. Currently, no assessment measures specific to the cognitive, affective, and behavioral dimensions of the construct of muscle dysmorphia have been published. To address this need, the authors developed the Muscle Appearance Satisfaction Scale (MASS), a brief 19-item self-report measure for the assessment of muscle dysmorphia symptoms. Psychometric evaluation of the MASS across two samples of male weight lifting participants (total N = 372) revealed a stable five-factor structure. An evaluation of factor content resulted in the following factor labels: Bodybuilding Dependence, Muscle Checking, Substance Use, Injury, and Muscle Satisfaction. Internal consistency, test-retest reliability, and construct validity were established with the MASS total score and its subscales. The authors believe the MASS will be a useful measure for research and applied work relating to muscle dysmorphia.

  8. Early body composition, but not body mass, is associated with future accelerated decline in muscle quality

    PubMed Central

    Chiles Shaffer, Nancy; Gonzalez‐Freire, Marta; Shardell, Michelle D.; Zoli, Marco; Studenski, Stephanie A.; Ferrucci, Luigi

    2017-01-01

    Abstract Background Muscle quality (MQ) or strength‐to‐mass ratio declines with aging, but the rate of MQ change with aging is highly heterogeneous across individuals. The identification of risk factors for accelerated MQ decline may offer clues to identity the underpinning physiological mechanisms and indicate targets for prevention and treatment. Using data from the Baltimore Longitudinal Study of Aging, we tested whether measures of body mass and body composition are associated with differential rates of changes in MQ with aging. Methods Participants included 511 men and women, aged 50 years or older, followed for an average of 4 years (range: 1–8). MQ was operationalized as ratio between knee‐extension isokinetic strength and CT‐thigh muscle cross‐sectional area. Predictors included body mass and body composition measures: weight (kg), body mass index (BMI, kg/m2), dual‐energy x‐ray absorptiometry‐measured total body fat mass (TFM, kg) and lean mass (TLM, kg), and body fatness (TFM/weight). Covariates were baseline age, sex, race, and body height. Results Muscle quality showed a significant linear decline over the time of the follow up (average rate of decline 0.02 Nm/cm2 per year, P < .001). Independent of covariates, neither baseline body weight (P = .756) nor BMI (P = .777) was predictive of longitudinal rate of decline in MQ. Instead, higher TFM and lower TLM at baseline predicted steeper longitudinal decline in MQ (P = .036 and P < .001, respectively). In particular, participants with both high TFM and low TLM at baseline experienced the most dramatic decline compared with those with low TFM and high TLM (about 3% per year vs. 0.5% per year, respectively). Participants in the higher tertile of baseline body fatness presented a significantly faster decline of MQ than the rest of the population (P = .021). Similar results were observed when body mass, TFM, and TLM were modeled as time‐dependent predictors. Conclusions Body

  9. Ratio of muscle mass to fat mass assessed by bioelectrical impedance analysis is significantly correlated with liver fat accumulation in patients with type 2 diabetes mellitus.

    PubMed

    Kurinami, Noboru; Sugiyama, Seigo; Morita, Ayami; Yoshida, Akira; Hieshima, Kunio; Miyamoto, Fumio; Kajiwara, Keizo; Jinnouch, Katsunori; Jinnouchi, Tomio; Jinnouchi, Hideaki

    2018-05-01

    Obesity and ectopic fat accumulation are important conditions of type 2 diabetes mellitus (T2DM). Our aim was to determine whether bioelectrical impedance body composition analysis combined with blood test results could estimate liver ectopic fat accumulation in patients with treatment-naïve T2DM. Subjects were 119 untreated T2DM patients. Computed tomography scans were performed to calculate the liver to spleen attenuation ratio (L/S ratio) as a measure of liver fat accumulation, with excess liver fat accumulation defined as an L/S ratio <1.0. Elementary body composition was measured by bioelectrical impedance analysis using InBody770. The Nagelkerke R 2 test showed that the muscle mass/fat mass ratio (muscle/fat ratio) was the most suitable variable among anthropometric factors and body component indexes for estimating liver fat accumulation. The muscle/fat ratio was significantly correlated with the L/S ratio (ρ = 0.4386, P < 0.0001). Multivariable logistic regression analysis showed that the muscle/fat ratio (odds ratio 0.40, 95% confidence interval 0.22-0.73, P < 0.01) and alanine aminotransferase (odds ratio 1.06, 95% confidence interval 1.02-1.10, P < 0.01) were independently and significantly associated with liver fat accumulation. In receiver operating characteristic curve analysis, the cutoff value of the muscle/fat ratio for excess liver fat accumulation was 2.34. In patients with treatment-naïve T2DM, the muscle/fat ratio and ALT are useful for estimating the presence of excess liver fat accumulation in daily clinical practice. Copyright © 2018. Published by Elsevier B.V.

  10. Visceral adiposity and skeletal muscle mass are independently and synergistically associated with left ventricular structure and function: the Korean Genome and Epidemiology Study.

    PubMed

    Park, Juri; Kim, Nan Hee; Kim, Seong Hwan; Kim, Jin-Seok; Kim, Yong Hyun; Lim, Hong Euy; Kim, Eung Ju; Na, Jin Oh; Cho, Goo-Yeong; Baik, Inkyung; Kim, Doo Man; Choi, Dong Seop; Lee, Seung Ku; Shin, Chol

    2014-10-20

    Obesity and low muscle mass may coexist as age-related changes in body composition. We aimed to investigate the effect of visceral adiposity and skeletal muscle mass on left ventricular (LV) structure and function in the general population. A total of 1941 participants without known cardiovascular disease were enrolled from the Korean Genome and Epidemiology Study. Visceral fat area (VFA) was assessed by computed tomography. Appendicular skeletal muscle mass (ASM) was estimated by dual-energy X-ray absorptiometry and was used as a percentage of body weight (ASM/Wt). LV structure and function were assessed by tissue Doppler imaging (TDI) echocardiography. Across VFA tertiles, ASM increased, but ASM/Wt decreased (all P<0.001). In multivariate models adjusted for conventional cardiovascular risk factors, LV mass index and LV diastolic parameters, such as left atrial dimension, TDI Ea velocity, and E/Ea ratio, were significantly impaired as VFA increased. On the other hand, an increase in ASM/Wt was associated with a decrease in LV mass index and improvement of LV diastolic parameters. With regard to LV mass index and TDI Ea velocity, VFA and ASM/Wt showed synergistic effects (all P interaction<0.05). When both VFA and ASM/Wt were simultaneously included in the same model, both remained independent predictors of LV mass index and TDI Ea velocity. More visceral fat and less muscle mass are independently and synergistically associated with an increase in LV mass index and impairment of LV diastolic parameters. Further research is needed to explore the complex mechanisms underlying these associations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Comparative anatomy and muscle architecture of selected hind limb muscles in the Quarter Horse and Arab.

    PubMed

    Crook, T C; Cruickshank, S E; McGowan, C M; Stubbs, N; Wakeling, J M; Wilson, A M; Payne, R C

    2008-02-01

    The Quarter Horse (bred for acceleration) and the Arab (bred for endurance) are situated at either end of the equine athletic spectrum. Studies into the form and function of the leg muscles in human sprint and endurance runners have demonstrated that differences exist in their muscle architecture. It is not known whether similar differences exist in the horse. Six Quarter Horse and six Arab fresh hind limb cadavers were dissected to gain information on the muscle mass and architecture of the following muscles: gluteus medius; biceps femoris; semitendinosus; vastus lateralis; gastrocnemius; tibialis cranialis and extensor digitorum longus. Specifically, muscle mass, fascicle length and pennation angle were quantified and physiological cross-sectional area (PCSA) and maximum isometric force were estimated. The hind limb muscles of the Quarter Horse were of a significantly greater mass, but had similar fascicle lengths and pennation angles when compared with those of the Arab; this resulted in the Quarter Horse hind limb muscles having greater PCSAs and hence greater isometric force potential. This study suggests that Quarter Horses as a breed inherently possess large strong hind limb muscles, with the potential to accelerate their body mass more rapidly than those of the Arab.

  12. Ultrasonographic evaluation of the calf muscle mass and architecture in elderly patients with and without sarcopenia.

    PubMed

    Kuyumcu, Mehmet Emin; Halil, Meltem; Kara, Özgür; Çuni, Bledjan; Çağlayan, Gökhan; Güven, Serdar; Yeşil, Yusuf; Arık, Güneş; Yavuz, Burcu Balam; Cankurtaran, Mustafa; Özçakar, Levent

    2016-01-01

    To sonographically assess the muscle mass and architecture of sarcopenic elderly subjects, and to explore the utility of ultrasound (US) measurements in predicting sarcopenia. One hundred elderly subjects were enrolled in this cross-sectional study. Mean age value of our study population was 73.08±6.18years. The diagnosis of sarcopenia was confirmed by measuring fat-free mass index (using bioelectrical impedance analysis) and handgrip strength. Calf circumference was measured and US evaluations comprised bilateral gastrocnemius muscle (MG) thickness, fascicle length and pennate angles; subcutaneous fat and dermis thicknesses in the calf. Bilateral muscle thickness and fascicle length values were significantly lower in patients with sarcopenia (both p<0.05). Sarcopenic and nonsarcopenic subjects had similar pennate angles, subcutaneous fat and dermis thicknesses. Median thickness ratio (100×t (MG)/[t (subcutaneous tissue)+t (dermis)+t (MG)]) values were 64% (40-88%) in the right and 64% (38-86%) in the left calf. Bilateral MG thickness and fascicle length values showed high sensitivity in predicting sarcopenia (all values>76.92%). Gastrocnemius muscle thickness and fascicle length values are lower in sarcopenic elderly and these two parameters can serve as alternative measurements for predicting/quantifying sarcopenia. Calf circumference measurements alone may not be appropriate for assessing sarcopenia. Instead, US imaging can conveniently be used to evaluate different compartments of the musculoskelal system in (sarcopenic) elderly. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. The effect of individualized nutritional counseling on muscle mass and treatment outcome in patients with metastatic colorectal cancer undergoing chemotherapy: a randomized controlled trial protocol.

    PubMed

    van der Werf, Anne; Blauwhoff-Buskermolen, Susanne; Langius, Jacqueline A E; Berkhof, Johannes; Verheul, Henk M W; de van der Schueren, Marian A E

    2015-03-05

    A low muscle mass is prevalent in patients with metastatic colorectal cancer (mCRC) and has been associated with poor treatment outcome. Chemotherapeutic treatment has an additional unfavorable effect on muscle mass. Sufficient protein intake and physical activity are known to induce muscle protein anabolism in healthy individuals, however it is unclear whether optimal nutrition is effective to preserve muscle mass in patients with mCRC during first-line chemotherapy as well. We hypothesize that individual nutritional counseling by a trained dietitian during first-line chemotherapy is effective in preserving muscle mass and may improve clinical outcomes in patients with mCRC. In this multi-center single-blind randomized controlled trial, patients with mCRC scheduled for first-line combination chemotherapy consisting of oxaliplatin and fluoropyrimidine, with or without bevacizumab (n = 110), will be randomized to receive either individualized nutritional counseling by a trained dietitian to achieve a sufficient dietary intake and an adequate physical activity level, or usual care. Outcome measures will be assessed at baseline and after two and four months of treatment. The primary endpoint will be the change in skeletal muscle area (measured by CT-scan) at the first treatment evaluation. Secondary endpoints will be quality of life, physical functioning, treatment toxicity, treatment intensity and survival. Statistical analyses include one-sided t-tests for the primary endpoint and mixed models and the Kaplan-Meier method for secondary endpoints. This randomized controlled trial will provide evidence whether individualized nutritional counseling during chemotherapy is effective in preventing loss of muscle mass in patients with mCRC. ClinicalTrials.gov NCT01998152 ; Netherlands Trial Register NTR4223.

  14. Muscle wasting and resistance of muscle anabolism: the "anabolic threshold concept" for adapted nutritional strategies during sarcopenia.

    PubMed

    Dardevet, Dominique; Rémond, Didier; Peyron, Marie-Agnès; Papet, Isabelle; Savary-Auzeloux, Isabelle; Mosoni, Laurent

    2012-01-01

    Skeletal muscle loss is observed in several physiopathological situations. Strategies to prevent, slow down, or increase recovery of muscle have already been tested. Besides exercise, nutrition, and more particularly protein nutrition based on increased amino acid, leucine or the quality of protein intake has generated positive acute postprandial effect on muscle protein anabolism. However, on the long term, these nutritional strategies have often failed in improving muscle mass even if given for long periods of time in both humans and rodent models. Muscle mass loss situations have been often correlated to a resistance of muscle protein anabolism to food intake which may be explained by an increase of the anabolic threshold toward the stimulatory effect of amino acids. In this paper, we will emphasize how this anabolic resistance may affect the intensity and the duration of the muscle anabolic response at the postprandial state and how it may explain the negative results obtained on the long term in the prevention of muscle mass. Sarcopenia, the muscle mass loss observed during aging, has been chosen to illustrate this concept but it may be kept in mind that it could be extended to any other catabolic states or recovery situations.

  15. Effect of modified fasting therapy on body weight, fat and muscle mass, and blood chemistry in patients with obesity.

    PubMed

    Kim, Koh-Woon; Song, Mi-Yeon; Chung, Seok-Hee; Chung, Won-Seok

    2016-02-01

    The aim of this study was to investigate the effects and safety of modified fasting therapy using fermented medicinal herbs and exercise on body weight, fat and muscle mass, and blood chemistry in obese subjects. Twenty-six patients participated in a 14-day fast, during which they ingested a supplement made from fermented medicinal herbs and carbohydrates (intake: 400-600 kcal/d). The schedule included 7 prefasting relief days and 14 days of stepwise reintroduction of food. The patients also took part in an exercise program that incorporated Qigong, weight training, and walking exercises. The efficacy of treatments was observed by assessing body fat mass and muscle mass, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), cholesterol, and triglycerides in each study period. Specific symptoms or side effects were reported. Body weight and body fat mass both decreased significantly by (5.16 ± 0.95) and (3.89 ± 0.79) kg (both P < 0.05), while muscle mass decreased by an average of (0.26 ± 0.22) kg, without statistical significance. ALT levels were significantly decreased (P < 0.05), while AST levels decreased without statistical significance (P = 0.052). The levels of total cholesterol and triglycerides were also significantly decreased (both P < 0.05). There were few adverse events except for mild dizziness, which did not affect everyday living. These results suggest that modified fasting therapy using fermented medicinal herbs and exercise could be effective and safe on obese patients.

  16. Calibration strategies for the determination of stable carbon absolute isotope ratios in a glycine candidate reference material by elemental analyser-isotope ratio mass spectrometry.

    PubMed

    Dunn, Philip J H; Malinovsky, Dmitry; Goenaga-Infante, Heidi

    2015-04-01

    We report a methodology for the determination of the stable carbon absolute isotope ratio of a glycine candidate reference material with natural carbon isotopic composition using EA-IRMS. For the first time, stable carbon absolute isotope ratios have been reported using continuous flow rather than dual inlet isotope ratio mass spectrometry. Also for the first time, a calibration strategy based on the use of synthetic mixtures gravimetrically prepared from well characterised, highly (13)C-enriched and (13)C-depleted glycines was developed for EA-IRMS calibration and generation of absolute carbon isotope ratio values traceable to the SI through calibration standards of known purity. A second calibration strategy based on converting the more typically determined delta values on the Vienna PeeDee Belemnite (VPDB) scale using literature values for the absolute carbon isotope ratio of VPDB itself was used for comparison. Both calibration approaches provided results consistent with those previously reported for the same natural glycine using MC-ICP-MS; absolute carbon ratios of 10,649 × 10(-6) with an expanded uncertainty (k = 2) of 24 × 10(-6) and 10,646 × 10(-6) with an expanded uncertainty (k = 2) of 88 × 10(-6) were obtained, respectively. The absolute carbon isotope ratio of the VPDB standard was found to be 11,115 × 10(-6) with an expanded uncertainty (k = 2) of 27 × 10(-6), which is in excellent agreement with previously published values.

  17. Effect of muscle mass and intensity of isometric contraction on heart rate.

    PubMed

    Gálvez, J M; Alonso, J P; Sangrador, L A; Navarro, G

    2000-02-01

    The purpose of this study was to determine the effect of muscle mass and the level of force on the contraction-induced rise in heart rate. We conducted an experimental study in a sample of 28 healthy men between 20 and 30 yr of age (power: 95%, alpha: 5%). Smokers, obese subjects, and those who performed regular physical activity over a certain amount of energetic expenditure were excluded from the study. The participants exerted two types of isometric contractions: handgrip and turning a 40-cm-diameter wheel. Both were sustained to exhaustion at 20 and 50% of maximal force. Twenty-five subjects finished the experiment. Heart rate increased a mean of 15.1 beats/min [95% confidence interval (CI): 5.5-24.6] from 20 to 50% handgrip contractions, and 20.7 beats/min (95% CI: 11.9-29.5) from 20 to 50% wheel-turn contractions. Heart rate also increased a mean of 13.3 beats/min (95% CI: 10.4-16.1) from handgrip to wheel-turn contractions at 20% maximal force, and 18.9 beats/min (95% CI: 9. 8-28.0) from handgrip to wheel-turn contractions at 50% maximal force. We conclude that the magnitude of the heart rate increase during isometric exercise is related to the intensity of the contraction and the mass of the contracted muscle.

  18. The Muscles Treasury Survey. I. Motivation and Overview

    NASA Technical Reports Server (NTRS)

    France, Kevin; Loyd, R. O. Parke; Youngblood, Allison; Brown, Alexander; Schneider, P. Christian; Hawley, Suzanne L.; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Buccino, Andrea P.

    2016-01-01

    Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun-Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectral energy distribution (SED), however, flux distributions of relatively inactive low-mass stars are poorly understood at present. To address this issue, we have executed a panchromatic (X-ray to mid-IR) study of the SEDs of 11 nearby planet-hosting stars, the Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (MUSCLES) Treasury Survey. The MUSCLES program consists visible observations from Hubble and ground-based observatories. Infrared and astrophysically inaccessible wavelengths (EUV and Lyalpha) are reconstructed using stellar model spectra to fill in gaps in the observational data. In this overview and the companion papers describing the MUSCLES survey, we show that energetic radiation (X-ray and ultraviolet) is present from magnetically active stellar atmospheres at all times for stars as late as M6. The emission line luminosities of C IV and Mg II are strongly correlated with band-integrated luminosities and we present empirical relations that can be used to estimate broadband FUV and XUV (is equivalent to X-ray + EUV) fluxes from individual stellar emission line measurements. We find that while the slope of the SED, FUV/NUV, increases by approximately two orders of magnitude form early K to late M dwarfs (approximately

  19. Chronic effect of light resistance exercise after ingestion of a high-protein snack on increase of skeletal muscle mass and strength in young adults.

    PubMed

    Kato, Yushi; Sawada, Atsushi; Numao, Shigeharu; Suzuki, Masashige

    2011-01-01

    We have previously reported on the possibility that light resistance exercise performed with a high plasma amino acid concentration resulting from the ingestion of a high-protein snack (HPS; 15 g protein, 18 g sugar) 3 h after a basal meal promotes the utilization of amino acids in peripheral tissues such as muscle in both rats and humans. In the present study, we further examined the effectiveness of a daily routine involving ingestion of HPS 3 h after a basal meal and subsequent light resistance exercise (dumbbell exercise) in increasing the mass and strength of human muscle. Ten young adult males were subject to the following 3 conditions for 5 wk each, with sufficient recovery period between each condition: (1) Snack-Exercise (SE), (2) Snack-Sedentary (SS), and (3) No snack-Exercise (NE). The SE group showed a significant increase in lean body mass and total cross-sectional area (CSA) of the right forearm muscles along with a significant decrease in body fat mass. The SS group showed no change in body composition. Furthermore, the SE group showed significant increase in grip strength and isometric knee extensor muscle strength, while the SS group showed no increase in muscle strength. The NE group showed significant increase in grip strength. In conclusion, daily routine ingestion of HPS 3 h after a basal meal and subsequent light resistance exercise is effective in increasing the mass and strength of human muscle.

  20. The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles.

    PubMed

    Cuff, Andrew R; Sparkes, Emily L; Randau, Marcela; Pierce, Stephanie E; Kitchener, Andrew C; Goswami, Anjali; Hutchinson, John R

    2016-07-01

    The body masses of cats (Mammalia, Carnivora, Felidae) span a ~300-fold range from the smallest to largest species. Despite this range, felid musculoskeletal anatomy remains remarkably conservative, including the maintenance of a crouched limb posture at unusually large sizes. The forelimbs in felids are important for body support and other aspects of locomotion, as well as climbing and prey capture, with the assistance of the vertebral (and hindlimb) muscles. Here, we examine the scaling of the anterior postcranial musculature across felids to assess scaling patterns between different species spanning the range of felid body sizes. The muscle architecture (lengths and masses of the muscle-tendon unit components) for the forelimb, cervical and thoracic muscles was quantified to analyse how the muscles scale with body mass. Our results demonstrate that physiological cross-sectional areas of the forelimb muscles scale positively with increasing body mass (i.e. becoming relatively larger). Many significantly allometric variables pertain to shoulder support, whereas the rest of the limb muscles become relatively weaker in larger felid species. However, when phylogenetic relationships were corrected for, most of these significant relationships disappeared, leaving no significantly allometric muscle metrics. The majority of cervical and thoracic muscle metrics are not significantly allometric, despite there being many allometric skeletal elements in these regions. When forelimb muscle data were considered in isolation or in combination with those of the vertebral muscles in principal components analyses and MANOVAs, there was no significant discrimination among species by either size or locomotory mode. Our results support the inference that larger felid species have relatively weaker anterior postcranial musculature compared with smaller species, due to an absence of significant positive allometry of forelimb or vertebral muscle architecture. This difference in strength

  1. Combined Strategies for Maintaining Skeletal Muscle Mass and Function in Aging: Myostatin Inactivation and AICAR-Associated Oxidative Metabolism Induction.

    PubMed

    Pauly, Marion; Chabi, Béatrice; Favier, François Bertrand; Vanterpool, Frankie; Matecki, Stefan; Fouret, Gilles; Bonafos, Béatrice; Vernus, Barbara; Feillet-Coudray, Christine; Coudray, Charles; Bonnieu, Anne; Ramonatxo, Christelle

    2015-09-01

    Myostatin (mstn) blockade, resulting in muscle hypertrophy, is a promising therapy to counteract age-related muscle loss. However, oxidative and mitochondrial deficit observed in young mice with myostatin inhibition could be detrimental with aging. The aim of this study was (a) to bring original data on metabolic and mitochondrial consequences of mstn inhibition in old mice, and (b) to examine whether 4-weeks of AICAR treatment, a pharmacological compound known to upregulate oxidative metabolism, may be useful to improve exercise capacity and mitochondrial deficit of 20-months mstn KO versus wild-type (WT) mice. Our results show that despite the enlarged muscle mass, the oxidative and mitochondrial deficit associated with reduced endurance running capacity is maintained in old mstn KO mice but not worsened by aging. Importantly, AICAR treatment induced a significant beneficial effect on running limit time only in old mstn KO mice, with a marked increase in PGC-1α expression and slight beneficial effects on mitochondrial function. We showed that AICAR effects were autophagy-independent. This study underlines the relevance of aged muscle remodelling by complementary approaches that impact both muscle mass and function, and suggest that mstn inhibition and aerobic metabolism activators should be co-developed for delaying age-related deficits in skeletal muscle. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Measurement of Muscle Protein Fractional Synthetic Rate by Capillary Gas Chromatography/Combustion Isotope Ratio Mass Spectrometry

    PubMed Central

    Yarasheski, Kevin E.; Smith, Kenneth; Rennie, Michael J.; Bier, Dennis M.

    2014-01-01

    The measurement of skeletal muscle protein fractional synthetic rate using an infusion of (1-13C)leucine and measuring the isotopic abundance of the tracer in skeletal muscle protein by preparative gas chromatography (GC)/ninhydrin isotope ratio mass spectrometry (IRMS) is laborious and subject to errors owing to contamination by 12C. The purpose of this study was to compare muscle (13C)leucine enrichment measured with the conventional preparative GC/ninhydrin IRMS approach to a new, continuous-flow technique using capillary GC/combustion IRMS. Quadriceps muscles were removed from four Sprague–Dawley rats after each was infused at a different rate with (1-13C)leucine for 6–8 h. Muscle leucine enrichment (at.% excess) measured by both methods differed by less than 4%, except at low (13C)leucine enrichments (<0.03 at.% excess). In addition, capillary GC/combustion IRMS was used to assess muscle (13C)leucine enrichment and fractional muscle protein synthesis rate in ten normal young men and women infused with (1,2-13C2)leucine for 12–14 h. This approach reduced the variability of the isotope abundance measure and gave estimates of muscle protein synthesis rate (0.050 ± 0.011% h−1 (mean ± SEM); range = 0.023–0.147% h−1) that agree with published values determined using the standard analytical approach. The measurement of (13C)leucine enrichment from skeletal muscle protein by capillary GC/combustion IRMS provides a simple, acceptable and practical alternative to preparative GC/ninhydrin IRMS. PMID:1420371

  3. Exercise Promotes Healthy Aging of Skeletal Muscle

    PubMed Central

    Cartee, Gregory D.; Hepple, Russell T.; Bamman, Marcas M.; Zierath, Juleen R.

    2016-01-01

    Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics, and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes “healthy aging” by inducing modifications in skeletal muscle. PMID:27304505

  4. Quantitative analysis of skeletal muscle mass in patients with rheumatic diseases under glucocorticoid therapy--comparison among bioelectrical impedance analysis, computed tomography, and magnetic resonance imaging.

    PubMed

    Hosono, Osamu; Yoshikawa, Noritada; Shimizu, Noriaki; Kiryu, Shigeru; Uehara, Masaaki; Kobayashi, Hiroshi; Matsumiya, Ryo; Kuribara, Akiko; Maruyama, Takako; Tanaka, Hirotoshi

    2015-03-01

    To determine the availability of bioelectrical impedance analysis (BIA), computed tomography (CT), and magnetic resonance imaging (MRI) for measurement of skeletal muscle mass in patients with rheumatic diseases and quantitatively assess skeletal muscle loss after glucocorticoid (GC) treatment. The data from 22 patients with rheumatic diseases were retrospectively obtained. The muscle mass of body segments was measured with a BIA device in terms of skeletal muscle mass index (SMI). Cross-sectional area (CSA) was obtained from CT and MRI scans at the mid-thigh level using the image analysis program. We further assessed the data of three different measurements before and after GC treatment in 7 patients with rheumatic diseases. SMI of whole body was significantly correlated with estimated muscle volume and mid-thigh muscle CSA with CT and MRI (p < 0.01). Significant correlations between SMI and mid-thigh muscle CSA of each leg were also found (p < 0.01). All the three measurements were negatively correlated with GC dosage (p < 0.01). Significant decline in mid-thigh muscle CSA with CT and MRI was found after GC treatment in 7 patients (p < 0.02). Those patients showed significant decline in SMI of whole body after GC treatment, but not in SMI of each leg. On the other hand, significant correlations between mid-thigh muscle CSA with CT and MRI were found before and after GC treatment (p < 0.01). GC-related skeletal muscle loss could be quantitatively assessed with BIA, CT, or MRI in patients with rheumatic diseases, and CT and MRI appeared to be more accurate than BIA.

  5. A low arm and leg muscle mass to total body weight ratio is associated with an increased prevalence of metabolic syndrome: The Korea National Health and Nutrition Examination Survey 2010-2011.

    PubMed

    Kim, Yong Hwan; So, Wi-Young

    2016-09-14

    The aim of this study was to investigate the association between metabolic syndrome (MetS) and arm and leg muscle mass to total weight ratios in Korean adults. This was a randomized, controlled, cross-sectional study. Data from 2,383 adults (1,030 men and 1,353 women) were collected from the Korea National Health and Nutrition Examination Survey 2010-2011. Blood lipid profiles, blood pressure, and anthropometric characteristics, including weight, height, waist circumference, and muscle mass on dual energy X-ray absorptiometry (DXA), were evaluated in the participants. MetS was defined according to the criteria of the National Cholesterol Education Program Adult Treatment Panel III. The average mass of both arms and legs was determined using regional muscle analysis by DXA. Afterwards, the arm and leg muscle mass to total body weight ratio was determined and classified into 4 quartiles (i.e., quartile 1 [highest muscle ratio] to quartile 4 [lowest muscle ratio]). According to the arm muscle and leg muscle ratios, there was a higher prevalence of MetS in quartile 4 than in quartile 1 in both men and women. A low arm and leg muscle mass to body weight ratio was associated with a higher prevalence of MetS after adjusting for age, physical activity, frequency of smoking, and frequency of alcohol consumption. In conclusion, MetS patients demonstrated a lower arm and leg muscle mass to body weight ratio. Strength training for the lower and upper extremities is recommended because it can have a positive effect on MetS prevention.

  6. Leucine modulation of mitochondrial mass and oxygen consumption in skeletal muscle cells and adipocytes

    PubMed Central

    Sun, Xiaocun; Zemel, Michael B

    2009-01-01

    Background The effects of dairy on energy metabolism appear to be mediated, in part, by leucine and calcium which regulate both adipocyte and skeletal muscle energy metabolism. We recently demonstrated that leucine and calcitriol regulate fatty acid oxidation in skeletal muscle cells in vitro, with leucine promoting and calcitriol suppressing fatty acid oxidation. Moreover, leucine coordinately regulated adipocyte lipid metabolism to promote flux of lipid to skeletal muscle and regulate metabolic flexibility. We have now investigated the role of mitochondrial biogenesis in mediating these effects. Methods We tested the effect of leucine, calcitriol and calcium in regulation of mitochondrial mass using a fluorescence method and tested mitochondrial biogenesis regulatory genes as well mitochondrial component genes using real-time PCR. We also evaluated the effect of leucine on oxygen consumption with a modified perfusion system. Results Leucine (0.5 mM) increased mitochondrial mass by 30% and 53% in C2C12 myocytes and 3T3-L1 adipocytes, respectively, while calcitriol (10 nM) decreased mitochondrial abundance by 37% and 27% (p < 0.02). Leucine also stimulated mitochondrial biogenesis genes SIRT-1, PGC-1α and NRF-1 as well as mitochondrial component genes UCP3, COX, and NADH expression by 3–5 fold in C2C12 cells (p < 0.003). Adipocyte-conditioned medium reduced mitochondrial abundance (p < 0.001) and decreased UCP3 but increased PGC-1α expression in myocytes, suggesting a feedback stimulation of mitochondrial biogenesis. Similar data were observed in C2C12 myocytes co-cultured with adipocytes, with co-culture markedly suppressing mitochondrial abundance (p < 0.02). Leucine stimulated oxygen consumption in both C2C12 cells and adipocytes compared with either control or valine-treated cells. Transfection of C2C12 myocytes with SIRT-1 siRNA resulted in parallel suppression of SIRT-1 expression and leucine-induced stimulation of PGC-1α and NRF-1, indicating that SIRT

  7. Absolute gravimetry for monitoring geodynamics in Greenland.

    NASA Astrophysics Data System (ADS)

    Nielsen, E.; Strykowski, G.; Forsberg, R.

    2015-12-01

    Here are presented the preliminary results of the absolute gravity measurements done in Greenland by DTU Space with their A10 absolute gravimeter (the A10-019). The purpose, besides establishing and maintaining a national gravity network, is to study geodynamics.The absolute gravity measurements are juxtaposed with the permanent GNET GNSS stations. The first measurements were conducted in 2009 and a few sites have been re-visited. As of present is there a gravity value at 18 GNET sites.There are challenges in interpreting the measurements from Greenland and several signals has to be taken into account, besides the geodynamical signals originating from the changing load of the ice, there is also a clear signal of direct attraction from different masses. Here are presented the preliminary results of our measurements in Greenland and attempts explain them through modelling of the geodynamical signals and the direct attraction from the ocean and ice.

  8. The influence of muscle fiber type composition on the patterns of responses for electromyographic and mechanomyographic amplitude and mean power frequency during a fatiguing submaximal isometric muscle action.

    PubMed

    Beck, T W; Housh, T J; Fry, A C; Cramer, J T; Weir, J P; Schilling, B K; Falvo, M J; Moore, C A

    2007-07-01

    The purpose of this investigation was to examine the influence of muscle fiber type composition on the patterns of responses for electromyographic (EMG) and mechanomyographic (MMG) amplitude and mean power frequency (MPF) during a fatiguing submaximal isometric muscle action. Five resistance-trained (mean +/- SD age = 23.2 +/- 3.7 yrs) and five aerobically-trained (mean +/- SD age = 32.6 +/- 5.2 yrs) men volunteered to perform a fatiguing, 30-sec submaximal isometric muscle action of the leg extensors at 50% of the maximum voluntary contraction (MVC). Muscle biopsies from the vastus lateralis revealed that the myosin heavy chain (MHC) composition for the resistance-trained subjects was 59.0 +/- 4.2% Type IIa, 0.1 +/- 0.1% Type IIx, and 40.9 +/- 4.3% Type I. The aerobically-trained subjects had 27.4 +/- 7.8% Type IIa, 0.0 +/- 0.0% Type IIx, and 72.6 +/- 7.8% Type I MHC. The patterns of responses and mean values for absolute and normalized EMG amplitude and MPF during the fatiguing muscle action were similar for the resistance-trained and aerobically-trained subjects. The resistance-trained subjects demonstrated relatively stable levels for absolute and normalized MMG amplitude and MPF across time, but the aerobically-trained subjects showed increases in MMG amplitude and decreases in MMG MPE The absolute MMG amplitude and MPF values for the resistance-trained subjects were also greater than those for the aerobi-cally-trained subjects. These findings suggested that unlike surface EMG, MMG may be a useful noninvasive technique for examining fatigue-related differences in muscle fiber type composition.

  9. Nandrolone normalizes determinants of muscle mass and fiber type after spinal cord injury.

    PubMed

    Wu, Yong; Zhao, Jingbo; Zhao, Weidong; Pan, Jiangping; Bauman, William A; Cardozo, Christopher P

    2012-05-20

    Spinal cord injury (SCI) results in atrophy of skeletal muscle and changes from slow oxidative to fast glycolytic fibers, which may reflect reduced levels of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), increased myostatin signaling, or both. In animals, testosterone reduces loss of muscle fiber cross-sectional area and activity of enzymes of energy metabolism. To identify the molecular mechanisms behind the benefits of androgens on paralyzed muscle, male rats were spinal cord transected and treated for 8 weeks with vehicle, testosterone at a physiological replacement dose, or testosterone plus nandrolone, an anabolic steroid. Treatments were initiated immediately after SCI and continued until the day animals were euthanized. In the SCI animals, gastrocnemius muscle mass was significantly increased by testosterone plus nandrolone, but not by testosterone alone. Both treatments significantly reduced nuclear content of Smad2/3 and mRNA levels of activin receptor IIB and follistatin-like 3. Testosterone alone or with nandrolone reversed SCI-induced declines in cellular and nuclear levels of PGC-1α protein and PGC-1α mRNA levels. For PGC-1α target genes, testosterone plus nandrolone partially reversed SCI-induced decreases in levels of proteins without corresponding increases in their mRNA levels. Thus, the findings demonstrate that following SCI, signaling through activin receptors and Smad2/3 is increased, and that androgens suppress activation of this signaling pathway. The findings also indicate that androgens upregulate PGC-1α in paralyzed muscle and promote its nuclear localization, but that these effects are insufficient to fully activate transcription of PGC-1α target genes. Furthermore, the transcription of these genes is not tightly coupled with their translation.

  10. Exercise Promotes Healthy Aging of Skeletal Muscle.

    PubMed

    Cartee, Gregory D; Hepple, Russell T; Bamman, Marcas M; Zierath, Juleen R

    2016-06-14

    Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Measurement of superficial and deep abdominal muscle thickness: an ultrasonography study.

    PubMed

    Tahan, Nahid; Khademi-Kalantari, Khosro; Mohseni-Bandpei, Mohammad Ali; Mikaili, Saeed; Baghban, Alireza Akbarzadeh; Jaberzadeh, Shapour

    2016-08-23

    Real-time ultrasound imaging is a valid method in the field of rehabilitation. The ultrasound imaging allows direct visualization for real-time study of the muscles as they contract over the time. Measuring of the size of each abdominal muscle in relation to the others provides useful information about the differences in structure, as well as data on trunk muscle activation patterns. The purpose of this study was to assess the size and symmetry of the abdominal muscles at rest in healthy adults and to provide a reference range of absolute abdominal muscle size in a relatively large population. A total 156 healthy subjects with the age range of 18-44 years were randomly recruited. The thickness of internal oblique, external oblique, transverse abdominis, and rectus abdominis muscles was measured at rest on both right and left sides using ultrasound. Independent t test was used to compare the mean thickness of each abdominal muscle between males and females. Differences on side-to-side thicknesses were assessed using paired t test. The association between abdominal muscle thicknesses with gender and anthropometric variables was examined using the Pearson correlation coefficient. A normal pattern of increasing order of mean abdominal muscle thickness was found in both genders at both right and left sides: transverse abdominis < external oblique < internal oblique < rectus abdominis. There was a significant difference on the size of transverse abdominis, internal oblique, and external oblique muscles between right and left sides in both genders. Males had significantly thicker abdominal muscles than females. Age was significantly correlated with the thickness of internal oblique, external oblique, and rectus abdominis muscles. Body mass index was also positively correlated with muscle thickness of rectus abdominis and external oblique. The results provide a normal reference range for the abdominal muscles in healthy subjects and may be used as an index to

  12. Effect of seven days of spaceflight on hindlimb muscle protein, RNA and DNA in adult rats

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Effects of seven days of spaceflight on skeletal muscle (soleus, gastrocnemius, EDL) content of protein, RNA and DNA were determined in adult rats. Whereas total protein contents were reduced in parallel with muscle weights, myofibrillar protein appeared to be more affected. There were no significant changes in absolute DNA contents, but a significant (P less than 0.05) increase in DNA concentration (microgram/milligram) in soleus muscles from flight rats. Absolute RNA contents were significantly (P less than 0.025) decreased in the soleus and gastrocnemius muscles of flight rats, with RNA concentrations reduced 15-30 percent. These results agree with previous ground-based observations on the suspended rat with unloaded hindlimbs and support continued use of this model.

  13. Metabolic adaptation of skeletal muscles to gravitational unloading

    NASA Astrophysics Data System (ADS)

    Ohira, Y.; Yasui, W.; Kariya, F.; Wakatsuki, T.; Nakamura, K.; Asakura, T.; Edgerton, V. R.

    Responses of high-energy phosphates and metabolic properties to hindlimb suspension were studied in adult rats. The relative content of phosphocreatine (PCr) in the calf muscles was significantly higher in rats suspended for 10 days than in age-matched cage controls. The Pi/PCr ratio, where Pi is inorganic phosphate, in suspended muscles was less than controls. The absolute weights of soleus and medial gastrocnemius (MG) were approximately 40% less than controls. Although the % fiber distribution in MG was unchanged, the % slow fibers decreased and the % fibers which were classified as both slow and fast was increased in soleus. The activities (per unit weight or protein) of succinate dehydrogenase and lactate dehydrogenase in soleus were unchanged but those of cytochrome oxidase, β-hydroxyacyl CoA dehydrogenase, and citrate synthase were decreased following unloading. None of these enzyme activities in MG changed. However, the total levels of all enzymes in whole muscles decreased by suspension. It is suggested that shift of slow muscle toward fast type by unloading is associated with a decrease in mitochondrial biogenesis. Further, gravitational unloading affected the levels of muscle proteins differently even in the same mitochondrial enzymes. Unloading-related atrophy is prominent in red muscle or slow-twitch fiber 1, 2. Such atrophy is accompanied by a shift of contractile properties toward fast-twitch type 2-9. Further, inhibition of mitochondrial metabolism in these muscles is also reported by some studies 10-14 suggesting a lowered mitochondrial biogenesis, although results from some studies do not necessarily agree 1, 7, 15. However, the precise mechanism responsible for such alterations of muscle properties in response to gravitational unloading is unclear. On the contrary, mitochondrial biogenesis, suggested by mitochondrial enzyme activities and/or mass, is stimulated in muscles with depleted high-energy phosphates by cold exposure 16 and/or by feeding

  14. The additional value of bioelectrical impedance analysis-derived muscle mass as a screening tool in geriatric assessment for fall prevention.

    PubMed

    Van Puyenbroeck, Karolien; Roelandts, Lieven; Van Deun, Thomas; Van Royen, Paul; Verhoeven, Veronique

    2012-01-01

    The decline in skeletal muscle in old age is a factor in the development of functional limitations. The objective of this study was to assess if there is a correlation between muscle mass based on bioelectrical impedance analysis (BIA) detection and the fall incidence in nursing home residents and to examine the risk factors for falling in nursing home residents. This prospective cohort study was part of a longitudinal study on nutritional issues in 52 nursing homes in Antwerp (Belgium) from October 2007 to April 2008. Two hundred and seventy-six people aged 65 years and older were included. Each subject was assessed with BIA, the timed get-up-and-go test, the Katz score, the Mini Nutritional Assessment - Short Form and the 36-Item Short Form Health Survey. The primary outcome parameter was fall incidence during the study. The prevalence of sarcopenia varied from 24.3 to 81.5% depending on which definition was used. No association was found between BIA-derived muscle mass and fall incidence. Logistic regression analysis showed that gait speed (odds ratio 1.029; p = 0.003) and mental health (odds ratio 0.981; p = 0.015) are significantly associated with fall incidence in nursing homes. A receiver operating characteristic curve showed that none of the BIA-derived muscle parameters are good predictors of the risk of falling. This study shows that there is no association between sarcopenia based on BIA and fall incidence and that BIA-derived muscle mass has no additional value in predicting fall incidents compared to the timed get-up-and-go test. Copyright © 2012 S. Karger AG, Basel.

  15. Metabolomic Analysis of Oxidative and Glycolytic Skeletal Muscles by Matrix-Assisted Laser Desorption/IonizationMass Spectrometric Imaging (MALDI MSI)

    NASA Astrophysics Data System (ADS)

    Tsai, Yu-Hsuan; Garrett, Timothy J.; Carter, Christy S.; Yost, Richard A.

    2015-06-01

    Skeletal muscles are composed of heterogeneous muscle fibers that have different physiological, morphological, biochemical, and histological characteristics. In this work, skeletal muscles extensor digitorum longus, soleus, and whole gastrocnemius were analyzed by matrix-assisted laser desorption/ionization mass spectrometry to characterize small molecule metabolites of oxidative and glycolytic muscle fiber types as well as to visualize biomarker localization. Multivariate data analysis such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed to extract significant features. Different metabolic fingerprints were observed from oxidative and glycolytic fibers. Higher abundances of biomolecules such as antioxidant anserine as well as acylcarnitines were observed in the glycolytic fibers, whereas taurine and some nucleotides were found to be localized in the oxidative fibers.

  16. Low vitamin D status is associated with reduced muscle mass and impaired physical performance in frail elderly people.

    PubMed

    Tieland, M; Brouwer-Brolsma, E M; Nienaber-Rousseau, C; van Loon, L J C; De Groot, L C P G M

    2013-10-01

    Serum 25-hydroxyvitamin D (25(OH)D) status has been associated with muscle mass, strength and physical performance in healthy elderly people. Yet, in pre-frail and frail elderly people this association has not been studied. The objective of this study was to explore the association between vitamin D intake and serum 25(OH)D status with muscle mass, strength and physical performance in a pre-frail and frail elderly population. This cross-sectional study included 127 pre-frail and frail elderly people in The Netherlands. Whole body and appendicular lean mass (ALM) (dual energy X-ray absorptiometry), leg strength (one repetition maximum), handgrip strength and physical performance (short physical performance battery) were measured, and blood samples were collected for the assessment of serum 25(OH)D status (liquid chromatography-tandem mass spectrometry). In addition, habitual dietary intake (3-day food records) and physical activity data (accelerometers) were collected. In total, 53% of the participants had a serum 25(OH)D level below 50  nmol/l. After adjustment for confounding factors, 25(OH)D status was associated with ALM (β=0.012, P=0.05) and with physical performance (β=0.020, P<0.05). Vitamin D intake was associated with physical performance (β=0.18, P<0.05) but not with ALM (P>0.05). In this frail elderly population, 25(OH)D status is low and suggests a modest association with reduced ALM and impaired physical performance. In addition, vitamin D intake tended to be associated with impaired physical performance. Our findings highlight the need for well-designed intervention trials to assess the impact of vitamin D supplementation on 25(OH)D status, muscle mass and physical performance in pre-frail and frail elderly people.

  17. CORE MUSCLE ACTIVITY DURING THE CLEAN AND JERK LIFT WITH BARBELL VERSUS SANDBAGS AND WATER BAGS.

    PubMed

    Calatayud, Joaquin; Colado, Juan C; Martin, Fernando; Casaña, José; Jakobsen, Markus D; Andersen, Lars L

    2015-11-01

    While the traditional clean and jerk maneuver implies simultaneous participation of a large number of muscle groups, the use of this exercise with some variations to enhance core muscle activity remains uninvestigated. The purpose of this study was to compare the muscle activity during clean and jerk lift when performed with a barbell, sandbag and a water bag at same absolute load. Descriptive, repeated-measures study. Twenty-one young fit male university students (age: 25 ± 2.66 years; height: 180.71 ± 5.42 cm; body mass: 80.32 ± 9.8 kg; body fat percentage: 12.41 ± 3.56 %) participated. Surface electromyographic (EMG) signals were recorded from the anterior deltoid (AD), external oblique (OBLIQ), lumbar erector spinae (LUMB), and gluteus medius (GM) and were expressed as a percentage of the maximum voluntary isometric contraction (MVIC). There were no significantly significant differences for AD muscle activity between conditions, whereas muscle activation values for OBLIQ (60%MVIC), GM (29%MVIC) and LUMB (85%MVIC) were significantly higher during the water bag power clean and jerk maneuver when compared with the other conditions. The clean and jerk is an exercise that may be used to enhance core muscle activity. Performing the maneuver with water bags resulted in higher core muscle activity compared with sandbag and standard barbell versions. 3.

  18. Beyond Body Mass Index. Is the Body Cell Mass Index (BCMI) a useful prognostic factor to describe nutritional, inflammation and muscle mass status in hospitalized elderly?: Body Cell Mass Index links in elderly.

    PubMed

    Rondanelli, Mariangela; Talluri, Jacopo; Peroni, Gabriella; Donelli, Chiara; Guerriero, Fabio; Ferrini, Krizia; Riggi, Emilia; Sauta, Elisabetta; Perna, Simone; Guido, Davide

    2018-06-01

    The aim of this study was to establish the effectiveness of Body Cell Mass Index (BCMI) as a prognostic index of (mal)nutrition, inflammation and muscle mass status in the elderly. A cross-sectional observational study has been conducted on 114 elderly patients (80 women and 34 men), with mean age equal to 81.07 ± 6.18 years. We performed a multivariate regression model by Structural Equation Modelling (SEM) framework. We detected the effects over a Mini Nutritional Assessment (MNA) stratification, by performing a multi-group multivariate regression model (via SEM) in two MNA nutritional strata, less and bigger (or equal) than 17. BCMI had a significant effect on albumin (β = +0.062, P = 0.001), adjusting for the other predictors of the model as Body Mass Index (BMI), age, sex, fat mass and cognitive condition. An analogous result is maintained in MNA<17 stratum. BMI has confirmed to be a solid prognostic factor for both free fat mass (FFM) (β = +0.480, P < 0.001) and Skeletal Muscle Index (SMI) (β = +0.265, P < 0.001), assessed by DXA. BCMI also returned suggestive evidences (0.05 < P < 0.10) for both the effect on FFM and on SMI in overall sample. The main result of this study is that the BCMI, compared to BMI, proved to be significantly related to an important marker as albumin in geriatric population. Then, assessing the BCMI could be a valuable, inexpensive, easy to perform tool to investigate the inflammation status of elderly patients. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  19. Does the Length of Elbow Flexors and Visual Feedback Have Effect on Accuracy of Isometric Muscle Contraction in Men after Stroke?

    PubMed Central

    Juodzbaliene, Vilma; Darbutas, Tomas; Skurvydas, Albertas

    2016-01-01

    The aim of the study was to determine the effect of different muscle length and visual feedback information (VFI) on accuracy of isometric contraction of elbow flexors in men after an ischemic stroke (IS). Materials and Methods. Maximum voluntary muscle contraction force (MVMCF) and accurate determinate muscle force (20% of MVMCF) developed during an isometric contraction of elbow flexors in 90° and 60° of elbow flexion were measured by an isokinetic dynamometer in healthy subjects (MH, n = 20) and subjects after an IS during their postrehabilitation period (MS, n = 20). Results. In order to evaluate the accuracy of the isometric contraction of the elbow flexors absolute errors were calculated. The absolute errors provided information about the difference between determinate and achieved muscle force. Conclusions. There is a tendency that greater absolute errors generating determinate force are made by MH and MS subjects in case of a greater elbow flexors length despite presence of VFI. Absolute errors also increase in both groups in case of a greater elbow flexors length without VFI. MS subjects make greater absolute errors generating determinate force without VFI in comparison with MH in shorter elbow flexors length. PMID:27042670

  20. High-frequency resistance training is not more effective than low-frequency resistance training in increasing muscle mass and strength in well-trained men.

    PubMed

    Gomes, Gederson K; Franco, Cristiane M; Nunes, Paulo Ricardo P; Orsatti, Fábio L

    2018-02-27

    We studied the effects of two different weekly frequency resistance training (RT) protocols over eight weeks on muscle strength and muscle hypertrophy in well-trained men. Twenty-three subjects (age: 26.2±4.2 years; RT experience: 6.9±3.1 years) were randomly allocated into the two groups: low frequency (LFRT, n = 12) or high frequency (HFRT, n = 11). The LFRT performed a split-body routine, training each specific muscle group once a week. The HFRT performed a total-body routine, training all muscle groups every session. Both groups performed the same number of sets (10-15 sets) and exercises (1-2 exercise) per week, 8-12 repetitions maximum (70-80% of 1RM), five times per week. Muscle strength (bench press and squat 1RM) and lean tissue mass (dual-energy x-ray absorptiometry) were assessed prior to and at the end of the study. Results showed that both groups improved (p<0.001) muscle strength [LFRT and HFRT: bench press = 5.6 kg (95% Confidence Interval (CI): 1.9 - 9.4) and 9.7 kg (95%CI: 4.6 - 14.9) and squat = 8.0 kg (95%CI: 2.7 - 13.2) and 12.0 kg (95%CI: 5.1 - 18.1), respectively] and lean tissue mass (p = 0.007) [LFRT and HFRT: total body lean mass = 0.5 kg (95%CI: 0.0 - 1.1) and 0.8 kg (95%CI: 0.0 - 1.6), respectively] with no difference between groups (bench press, p = 0.168; squat, p = 0.312 and total body lean mass, p = 0.619). Thus, HFRT and LFRT are similar overload strategies for promoting muscular adaptation in well-trained subjects when the sets and intensity are equated per week.

  1. Muscle oxygenation and fascicle length during passive muscle stretching in ballet-trained subjects.

    PubMed

    Otsuki, A; Fujita, E; Ikegawa, S; Kuno-Mizumura, M

    2011-07-01

    Muscle stretching transiently decreases muscle-blood flow corresponding to a muscle extension. It may disturb a balance between muscular oxygen demand and oxygen supply to muscles and reduce muscle oxygenation. However, muscle-stretching training may improve blood circulatory condition, resulting in the maintained muscle oxygenation during muscle stretching. The aim of this study was to investigate changes in muscle-blood volume (tHb) and tissue oxygenation index (TOI) during muscle stretching determined by using near-infrared spectroscopy (NIRS) in ballet-trained (BT) and untrained (C) subjects. 11 BT women who regularly perform muscle stretching and 11 C women participated in this study. Fascicle lengths, tHb and TOI in the tibialis anterior muscle were measured during passive plantar flexion from ankle joint angles of 120° (baseline) to 140°, 160°, the maximal comfortable position without pain (CP), and the maximal position (MP). At 160°, the % fascicle-length change from baseline was significantly lower in the BT than the C group, however, for the changes in tHb and TOI the significant interaction effect between the 2 groups was not detected. On the other hand, although the increases in the fascicle length from baseline to CP and MP were greater in BT than C, the tHb and TOI reductions were comparable between groups. We concluded that it appears that BT can extend their muscles without excessive reduction in muscle-blood volume and muscle oxygenation at relatively same but absolutely greater muscle-stretching levels than C. The attenuation in these indices during high-level muscle stretching may be associated with the repetitive muscle stretching of long-term ballet training. © Georg Thieme Verlag KG Stuttgart · New York.

  2. The Impact of Muscle Disuse on Muscle Atrophy in Severely Burned Rats

    DTIC Science & Technology

    2010-12-01

    Following muscle collection from the right hindlimb, muscle isometric force of PL and SL was measured simultaneously in the left hindlimb under...37.5°C by manually adjusting the temperature of cir culating water in the rat surgical bed. The isometric force of the PL and SL muscles was then...the physiologic cross sectional area (CSA) of PL and SL was calculated using the following formula: CSA= ( muscle mass) × cos θ ( muscle fiber

  3. Plasma levels of the pro-inflammatory protein S100A12 (EN-RAGE) are associated with muscle and fat mass in hemodialysis patients: a cross-sectional study

    PubMed Central

    2014-01-01

    Background Malnutrition is highly prevalent and contributes to mortality in hemodialysis (HD) patients. Although the receptor for advanced glycation end products (RAGE) system also contributes to the morbidity and mortality of these patients, the role that the RAGE system plays in determining nutritional status is currently unknown. Methods A cross-sectional study examining 79 HD patients was performed. The plasma concentrations of the soluble RAGE (sRAGE) and S100A12 (also known as EN-RAGE) were studied to evaluate their association with nutritional status, which was assessed by measuring the mid-thigh muscle mass and subcutaneous fat mass with computed tomography. Results Plasma S100A12 concentrations were shown to be significantly and negatively correlated with muscle mass and with fat mass (r = −0.237, P < 0.05 and r = −0.261, P < 0.05, respectively). In contrast, sRAGE was not shown to significantly correlate with either of these factors. Multiple regression analyses demonstrated that S100A12 is a significant independent predictor of both muscle mass and fat mass (P < 0.01 and P < 0.05, respectively). Conclusions Our findings suggest that plasma S100A12 levels could play an important role in determining muscle mass and fat mass in HD patients. Trial registration Study number; UMIN000012341. PMID:24884769

  4. Interactive effects of growth hormone and exercise on muscle mass in suspended rats

    NASA Technical Reports Server (NTRS)

    Grindeland, Richard E.; Roy, Roland R.; Edgerton, V. Reggie; Grossman, Elena J.; Mukku, Venkat R.; Jiang, Bian; Pierotti, David J.; Rudolph, Ingrid

    1994-01-01

    Measures to attenuate muscle atrophy in rats in response to simulated microgravity (hindlimb suspension (HS)) have been only partially successful. In the present study, hypophysectomized rats were in HS for 7 days, and the effects of recombinant human growth hormone (GH), exercise (Ex), or GH+Ex on the weights, protein concentrations, and fiber cross-sectional areas (CSAs) of hindlimb muscles were determined. The weights of four extensor muscles, i.e., the soleus (Sol), medial (MG) and lateral (LG) gastrocnemius, and plantaris (Plt), and one adductor, i.e., the adductor longus (AL), were decreased by 10-22% after HS. Fiber CSAs were decreased by 34% in the Sol and by 1 17% in the MG after HS. In contrast, two flexors, i.e., the tibialis anterior (TA) and extensor digitorum longus (EDL), did not atrophy. In HS rats, GH treatment alone maintained the weights of the fast extensors (MG, LG, Plt) and flexors (TA, EDL) at or above those of control rats. This effect was not observed in the slow extensor (Sol) or AL. Exercise had no significant effect on the weight of any muscle in HS rats. A combination of GH and Ex treatments yielded a significant increase in the weights of the fast extensors and in the CSA of both fast and slow fibers of the MG and significantly increased Sol weight and CSA of the slow fibers of the Sol. The AL was not responsive to either GH or Ex treatments. Protein concentrations of the Sol and MG were higher only in the Sol of Ex and GH+Ex rats. These results suggest that while GH treatment or intermittent high intensity exercise alone have a minimal effect in maintaining the mass of unloaded muscle, there is a strong interactive effect of these two treatments.

  5. Nandrolone Normalizes Determinants of Muscle Mass and Fiber Type after Spinal Cord Injury

    PubMed Central

    Wu, Yong; Zhao, Jingbo; Zhao, Weidong; Pan, Jiangping; Bauman, William A.

    2012-01-01

    Abstract Spinal cord injury (SCI) results in atrophy of skeletal muscle and changes from slow oxidative to fast glycolytic fibers, which may reflect reduced levels of peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), increased myostatin signaling, or both. In animals, testosterone reduces loss of muscle fiber cross-sectional area and activity of enzymes of energy metabolism. To identify the molecular mechanisms behind the benefits of androgens on paralyzed muscle, male rats were spinal cord transected and treated for 8 weeks with vehicle, testosterone at a physiological replacement dose, or testosterone plus nandrolone, an anabolic steroid. Treatments were initiated immediately after SCI and continued until the day animals were euthanized. In the SCI animals, gastrocnemius muscle mass was significantly increased by testosterone plus nandrolone, but not by testosterone alone. Both treatments significantly reduced nuclear content of Smad2/3 and mRNA levels of activin receptor IIB and follistatin-like 3. Testosterone alone or with nandrolone reversed SCI-induced declines in cellular and nuclear levels of PGC-1α protein and PGC-1α mRNA levels. For PGC-1α target genes, testosterone plus nandrolone partially reversed SCI-induced decreases in levels of proteins without corresponding increases in their mRNA levels. Thus, the findings demonstrate that following SCI, signaling through activin receptors and Smad2/3 is increased, and that androgens suppress activation of this signaling pathway. The findings also indicate that androgens upregulate PGC-1α in paralyzed muscle and promote its nuclear localization, but that these effects are insufficient to fully activate transcription of PGC-1α target genes. Furthermore, the transcription of these genes is not tightly coupled with their translation. PMID:22208735

  6. mRNA Expression Signatures of Human Skeletal Muscle Atrophy Identify a Natural Compound that Increases Muscle Mass

    PubMed Central

    Kunkel, Steven D.; Suneja, Manish; Ebert, Scott M.; Bongers, Kale S.; Fox, Daniel K.; Malmberg, Sharon E.; Alipour, Fariborz; Shields, Richard K.; Adams, Christopher M.

    2011-01-01

    SUMMARY Skeletal muscle atrophy is a common and debilitating condition that lacks a pharmacologic therapy. To develop a potential therapy, we identified 63 mRNAs that were regulated by fasting in both human and mouse muscle, and 29 mRNAs that were regulated by both fasting and spinal cord injury in human muscle. We used these two unbiased mRNA expression signatures of muscle atrophy to query the Connectivity Map, which singled out ursolic acid as a compound whose signature was opposite to those of atrophy-inducing stresses. A natural compound enriched in apples, ursolic acid reduced muscle atrophy and stimulated muscle hypertrophy in mice. It did so by enhancing skeletal muscle insulin/IGF-I signaling, and inhibiting atrophy-associated skeletal muscle mRNA expression. Importantly, ursolic acid’s effects on muscle were accompanied by reductions in adiposity, fasting blood glucose and plasma cholesterol and triglycerides. These findings identify a potential therapy for muscle atrophy and perhaps other metabolic diseases. PMID:21641545

  7. Low skeletal muscle mass is associated with poor structural parameters of bone and impaired balance in elderly men--the MINOS study.

    PubMed

    Szulc, Pawel; Beck, Tom J; Marchand, François; Delmas, Pierre D

    2005-05-01

    In 796 men, 50-85 years of age, decreased relative skeletal muscle mass index was associated with narrower bones, thinner cortices, and a consequent decreased bending strength (lower section modulus), as well as with impaired balance and an increased risk of falls. In men, appendicular skeletal muscle mass (ASM) is correlated positively with BMC and areal BMD (aBMD). In elderly men, low muscle mass and strength (sarcopenia) is associated with difficulties in daily living activities. The aim of this study was to evaluate if ASM is correlated with bone size, mechanical properties of bones, balance, and risk of falls in elderly men. This study used 796 men, 50-85 years of age, belonging to the MINOS cohort. Lifestyle factors were evaluated by standardized questionnaires. Estimates of mechanical bone properties were derived from aBMD measured by DXA. ASM was estimated by DXA. The relative skeletal muscle mass index (RASM) was calculated as ASM/(body height)(2.3). After adjustment for age, body size, tobacco smoking, professional physical activity, and 17beta-estradiol concentration, RASM was correlated positively with BMC, aBMD, external diameter, and cortical thickness (r = 0.17-0.34, p < 0.0001) but not with volumetric BMD. Consequently, RASM was correlated with section modulus (r = 0.29-0.39, p < 0.0001). Men in the lowest quartile of RASM had section modulus of femoral neck and distal radius lower by 12-18% in comparison with men in the highest quartile of RASM. In contrast, bone width was not correlated with fat mass, reflecting the load of body weight (except for L(3)), which suggests that the muscular strain may exert a direct stimulatory effect on periosteal apposition. After adjustment for confounding variables, a decrease in RASM was associated with increased risk of falls and of inability to accomplish clinical tests of muscle strength, static balance, and dynamic balance (odds ratio per 1 SD decrease in RASM, 1.31-2.23; p < 0.05-0.001). In elderly men

  8. Lactobacillus plantarum TWK10 Supplementation Improves Exercise Performance and Increases Muscle Mass in Mice

    PubMed Central

    Chen, Yi-Ming; Wei, Li; Chiu, Yen-Shuo; Hsu, Yi-Ju; Tsai, Tsung-Yu; Wang, Ming-Fu; Huang, Chi-Chang

    2016-01-01

    Lactobacillus plantarum (L. plantarum) is a well-known probiotic among the ingested-microorganism probiotics (i.e., ingested microorganisms associated with beneficial effects for the host). However, few studies have examined the effects of L. plantarum TWK10 (LP10) supplementation on exercise performance, physical fatigue, and gut microbial profile. Male Institute of Cancer Research (ICR) strain mice were divided into three groups (n = 8 per group) for oral administration of LP10 for six weeks at 0, 2.05 × 108, or 1.03 × 109 colony-forming units/kg/day, designated the vehicle, LP10-1X and LP10-5X groups, respectively. LP10 significantly decreased final body weight and increased relative muscle weight (%). LP10 supplementation dose-dependently increased grip strength (p < 0.0001) and endurance swimming time (p < 0.001) and decreased levels of serum lactate (p < 0.0001), ammonia (p < 0.0001), creatine kinase (p = 0.0118), and glucose (p = 0.0151) after acute exercise challenge. The number of type I fibers (slow muscle) in gastrocnemius muscle significantly increased with LP10 treatment. In addition, serum levels of albumin, blood urea nitrogen, creatinine, and triacylglycerol significantly decreased with LP10 treatment. Long-term supplementation with LP10 may increase muscle mass, enhance energy harvesting, and have health-promotion, performance-improvement, and anti-fatigue effects. PMID:27070637

  9. Hindlimb suspension reduces muscle regeneration

    NASA Technical Reports Server (NTRS)

    Mozdziak, P. E.; Truong, Q.; Macius, A.; Schultz, E.

    1998-01-01

    Exposure of juvenile skeletal muscle to a weightless environment reduces growth and satellite cell mitotic activity. However, the effect of a weightless environment on the satellite cell population during muscle repair remains unknown. Muscle injury was induced in rat soleus muscles using the myotoxic snake venom, notexin. Rats were placed into hindlimb-suspended or weightbearing groups for 10 days following injury. Cellular proliferation during regeneration was evaluated using 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and image analysis. Hindlimb suspension reduced (P < 0.05) regenerated muscle mass, regenerated myofiber diameter, uninjured muscle mass, and uninjured myofiber diameter compared to weightbearing rats. Hindlimb suspension reduced (P < 0.05) BrdU labeling in uninjured soleus muscles compared to weight-bearing muscles. However, hindlimb suspension did not abolish muscle regeneration because myofibers formed in the injured soleus muscles of hindlimb-suspended rats, and BrdU labeling was equivalent (P > 0.10) on myofiber segments isolated from the soleus muscles of hindlimb-suspended and weightbearing rats following injury. Thus, hindlimb suspension (weightlessness) does not suppress satellite cell mitotic activity in regenerating muscles before myofiber formation, but reduces growth of the newly formed myofibers.

  10. The MUSCLES Treasury Survey. I. Motivation and Overview

    NASA Astrophysics Data System (ADS)

    France, Kevin; Loyd, R. O. Parke; Youngblood, Allison; Brown, Alexander; Schneider, P. Christian; Hawley, Suzanne L.; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Buccino, Andrea P.; Davenport, James R. A.; Fontenla, Juan M.; Kaltenegger, Lisa; Kowalski, Adam F.; Mauas, Pablo J. D.; Miguel, Yamila; Redfield, Seth; Rugheimer, Sarah; Tian, Feng; Vieytes, Mariela C.; Walkowicz, Lucianne M.; Weisenburger, Kolby L.

    2016-04-01

    Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun-Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectral energy distribution (SED), however, flux distributions of relatively inactive low-mass stars are poorly understood at present. To address this issue, we have executed a panchromatic (X-ray to mid-IR) study of the SEDs of 11 nearby planet-hosting stars, the Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (MUSCLES) Treasury Survey. The MUSCLES program consists visible observations from Hubble and ground-based observatories. Infrared and astrophysically inaccessible wavelengths (EUV and Lyα) are reconstructed using stellar model spectra to fill in gaps in the observational data. In this overview and the companion papers describing the MUSCLES survey, we show that energetic radiation (X-ray and ultraviolet) is present from magnetically active stellar atmospheres at all times for stars as late as M6. The emission line luminosities of C IV and Mg II are strongly correlated with band-integrated luminosities and we present empirical relations that can be used to estimate broadband FUV and XUV (≡X-ray + EUV) fluxes from individual stellar emission line measurements. We find that while the slope of the SED, FUV/NUV, increases by approximately two orders of magnitude form early K to late M dwarfs (≈0.01-1), the absolute FUV and

  11. THE MUSCLES TREASURY SURVEY. I. MOTIVATION AND OVERVIEW

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

    France, Kevin; Loyd, R. O. Parke; Youngblood, Allison

    2016-04-01

    Ground- and space-based planet searches employing radial velocity techniques and transit photometry have detected thousands of planet-hosting stars in the Milky Way. With so many planets discovered, the next step toward identifying potentially habitable planets is atmospheric characterization. While the Sun–Earth system provides a good framework for understanding the atmospheric chemistry of Earth-like planets around solar-type stars, the observational and theoretical constraints on the atmospheres of rocky planets in the habitable zones (HZs) around low-mass stars (K and M dwarfs) are relatively few. The chemistry of these atmospheres is controlled by the shape and absolute flux of the stellar spectralmore » energy distribution (SED), however, flux distributions of relatively inactive low-mass stars are poorly understood at present. To address this issue, we have executed a panchromatic (X-ray to mid-IR) study of the SEDs of 11 nearby planet-hosting stars, the Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems (MUSCLES) Treasury Survey. The MUSCLES program consists visible observations from Hubble and ground-based observatories. Infrared and astrophysically inaccessible wavelengths (EUV and Lyα) are reconstructed using stellar model spectra to fill in gaps in the observational data. In this overview and the companion papers describing the MUSCLES survey, we show that energetic radiation (X-ray and ultraviolet) is present from magnetically active stellar atmospheres at all times for stars as late as M6. The emission line luminosities of C iv and Mg ii are strongly correlated with band-integrated luminosities and we present empirical relations that can be used to estimate broadband FUV and XUV (≡X-ray + EUV) fluxes from individual stellar emission line measurements. We find that while the slope of the SED, FUV/NUV, increases by approximately two orders of magnitude form early K to late M dwarfs (≈0.01–1), the

  12. Jasmine absolute (Jasminum grandiflora L.) and its mode of action on guinea-pig ileum in vitro.

    PubMed

    Lis-Balchin, M; Hart, S; Wan Hang Lo, B

    2002-08-01

    Jasmine (Jasminum grandiflorum L.) is used in aromatherapy as a holistic treatment for apathy, hysteria, uterine disorders and childbirth, muscle relaxation and coughs. Its stimulant nature, on inhalation, has been shown both in animals and man. Jasmine has a spasmolytic activity on guinea-pig ileum and rat uterus in vitro. The mechanism of action of the spasmolytic activity, studied in vitro using a guinea-pig ileum smooth muscle preparation, was postsynaptic and not atropine-like. The spasmolytic effect of jasmine absolute was most likely to be mediated through cAMP, and not through cGMP. The mode of action in vitro resembled that of geranium, lavender and peppermint oils. The contradictory effect in vitro and in vivo is probably due to the solely physiological effects of jasmine absolute in vitro (producing a relaxation) compared with that in vivo, where it has a strong psychological input, producing a stimulant effect in man and enhanced movement in animals. Copyright 2002 John Wiley & Sons, Ltd.

  13. Administration of soluble activin receptor 2B increases bone and muscle mass in a mouse model of osteogenesis imperfecta

    PubMed Central

    DiGirolamo, Douglas J.; Singhal, Vandana; Chang, Xiaoli; Lee, Se-Jin; Germain-Lee, Emily L.

    2015-01-01

    Osteogenesis imperfecta (OI) comprises a group of heritable connective tissue disorders generally defined by recurrent fractures, low bone mass, short stature and skeletal fragility. Beyond the skeletal complications of OI, many patients also report intolerance to physical activity, fatigue and muscle weakness. Indeed, recent studies have demonstrated that skeletal muscle is also negatively affected by OI, both directly and indirectly. Given the well-established interdependence of bone and skeletal muscle in both physiology and pathophysiology and the observations of skeletal muscle pathology in patients with OI, we investigated the therapeutic potential of simultaneous anabolic targeting of both bone and skeletal muscle using a soluble activin receptor 2B (ACVR2B) in a mouse model of type III OI (oim). Treatment of 12-week-old oim mice with ACVR2B for 4 weeks resulted in significant increases in both bone and muscle that were similar to those observed in healthy, wild-type littermates. This proof of concept study provides encouraging evidence for a holistic approach to treating the deleterious consequences of OI in the musculoskeletal system. PMID:26161291

  14. Efficacy of a novel formulation of L-Carnitine, creatine, and leucine on lean body mass and functional muscle strength in healthy older adults: a randomized, double-blind placebo-controlled study.

    PubMed

    Evans, Malkanthi; Guthrie, Najla; Pezzullo, John; Sanli, Toran; Fielding, Roger A; Bellamine, Aouatef

    2017-01-01

    Progressive decline in skeletal muscle mass and function are growing concerns in an aging population. Diet and physical activity are important for muscle maintenance but these requirements are not always met. This highlights the potential for nutritional supplementation. As a primary objective, we sought to assess the effect of a novel combination of L-Carnitine, creatine and leucine on muscle mass and performance in older subjects. Forty-two healthy older adults aged 55-70 years were randomized to receive either a novel L-Carnitine (1500 mg), L-leucine (2000 mg), creatine (3000 mg), Vitamin D3 (10 μg) (L-Carnitine-combination) product ( n  = 14), L-Carnitine (1500 mg) ( n  = 14), or a placebo ( n  = 14) for eight weeks. We evaluated body mass by DXA, upper and lower strength by dynamometry, and walking distance by a 6-min walk test at baseline and after eight weeks of intervention. These measures, reflecting muscle mass, functional strength and mobility have been combined to generate a primary composite score. Quality of life, blood safety markers, and muscle biopsies for protein biomarker analysis were also conducted at baseline and the end of the study. The primary composite outcome improved by 63.5 percentage points in the L-Carnitine-combination group vs. placebo ( P  = 0.013). However, this composite score did not change significantly in the L-Carnitine group ( P =  0.232), and decreased slightly in the placebo group ( P =  0.534). Participants supplemented with the L-Carnitine-combination showed a 1.0 kg increase in total lean muscle mass ( P  = 0.013), leg lean muscle mass (0.35 kg, P =  0.005), and a 1.0 kg increase in lower leg strength ( P  = 0.029) at week 8. In addition, these increases were significant when compared to the placebo group (P =  0.034, P =  0.026, and P =  0.002, respectively). Total mTOR protein expression was increased in participants in the L-Carnitine-combination group at the end of

  15. Inhibition of Stat3 activation suppresses caspase-3 and the ubiquitin-proteasome system, leading to preservation of muscle mass in cancer cachexia.

    PubMed

    Silva, Kleiton Augusto Santos; Dong, Jiangling; Dong, Yanjun; Dong, Yanlan; Schor, Nestor; Tweardy, David J; Zhang, Liping; Mitch, William E

    2015-04-24

    Cachexia occurs in patients with advanced cancers. Despite the adverse clinical impact of cancer-induced muscle wasting, pathways causing cachexia are controversial, and clinically reliable therapies are not available. A trigger of muscle protein loss is the Jak/Stat pathway, and indeed, we found that conditioned medium from C26 colon carcinoma (C26) or Lewis lung carcinoma cells activates Stat3 (p-Stat3) in C2C12 myotubes. We identified two proteolytic pathways that are activated in muscle by p-Stat3; one is activation of caspase-3, and the other is p-Stat3 to myostatin, MAFbx/Atrogin-1, and MuRF-1 via CAAT/enhancer-binding protein δ (C/EBPδ). Using sequential deletions of the caspase-3 promoter and CHIP assays, we determined that Stat3 activation increases caspase-3 expression in C2C12 cells. Caspase-3 expression and proteolytic activity were stimulated by p-Stat3 in muscles of tumor-bearing mice. In mice with cachexia caused by Lewis lung carcinoma or C26 tumors, knock-out of p-Stat3 in muscle or with a small chemical inhibitor of p-Stat3 suppressed muscle mass losses, improved protein synthesis and degradation in muscle, and increased body weight and grip strength. Activation of p-Stat3 stimulates a pathway from C/EBPδ to myostatin and expression of MAFbx/Atrogin-1 and increases the ubiquitin-proteasome system. Indeed, C/EBPδ KO decreases the expression of MAFbx/Atrogin-1 and myostatin, while increasing muscle mass and grip strength. In conclusion, cancer stimulates p-Stat3 in muscle, activating protein loss by stimulating caspase-3, myostatin, and the ubiquitin-proteasome system. These results could lead to novel strategies for preventing cancer-induced muscle wasting. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Inhibition of Stat3 Activation Suppresses Caspase-3 and the Ubiquitin-Proteasome System, Leading to Preservation of Muscle Mass in Cancer Cachexia*

    PubMed Central

    Silva, Kleiton Augusto Santos; Dong, Jiangling; Dong, Yanjun; Dong, Yanlan; Schor, Nestor; Tweardy, David J.; Zhang, Liping; Mitch, William E.

    2015-01-01

    Cachexia occurs in patients with advanced cancers. Despite the adverse clinical impact of cancer-induced muscle wasting, pathways causing cachexia are controversial, and clinically reliable therapies are not available. A trigger of muscle protein loss is the Jak/Stat pathway, and indeed, we found that conditioned medium from C26 colon carcinoma (C26) or Lewis lung carcinoma cells activates Stat3 (p-Stat3) in C2C12 myotubes. We identified two proteolytic pathways that are activated in muscle by p-Stat3; one is activation of caspase-3, and the other is p-Stat3 to myostatin, MAFbx/Atrogin-1, and MuRF-1 via CAAT/enhancer-binding protein δ (C/EBPδ). Using sequential deletions of the caspase-3 promoter and CHIP assays, we determined that Stat3 activation increases caspase-3 expression in C2C12 cells. Caspase-3 expression and proteolytic activity were stimulated by p-Stat3 in muscles of tumor-bearing mice. In mice with cachexia caused by Lewis lung carcinoma or C26 tumors, knock-out of p-Stat3 in muscle or with a small chemical inhibitor of p-Stat3 suppressed muscle mass losses, improved protein synthesis and degradation in muscle, and increased body weight and grip strength. Activation of p-Stat3 stimulates a pathway from C/EBPδ to myostatin and expression of MAFbx/Atrogin-1 and increases the ubiquitin-proteasome system. Indeed, C/EBPδ KO decreases the expression of MAFbx/Atrogin-1 and myostatin, while increasing muscle mass and grip strength. In conclusion, cancer stimulates p-Stat3 in muscle, activating protein loss by stimulating caspase-3, myostatin, and the ubiquitin-proteasome system. These results could lead to novel strategies for preventing cancer-induced muscle wasting. PMID:25787076

  17. The Mega-MUSCLES Treasury Survey: Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems

    NASA Astrophysics Data System (ADS)

    Froning, Cynthia

    2017-08-01

    JWST will be able to observe the atmospheres of rocky planets transiting nearby M dwarfs. A few such planets are already known (around GJ1132, Proxima Cen, and Trappist-1) and TESS is predicted to find many more, including 14 habitable zone planets. To interpret observations of these exoplanets' atmospheres, we must understand the high-energy SED of their host stars: X-ray/EUV irradiation can erode a planet's gaseous envelope and FUV/NUV-driven photochemistry shapes an atmosphere's molecular abundances, including potential biomarkers like O2, O3, and CH4. Our MUSCLES Treasury Survey (Cycles 19+22) used Hubble/COS+STIS UV observations with contemporaneous X-ray and ground-based data to construct complete SEDs for 11 low-mass exoplanet hosts. MUSCLES is the most widely used database for early-M and K dwarf (>0.3 M_sun) irradiance spectra and has supported a wide range of atmospheric stability and biomarker modeling work. However, TESS will find most of its habitable planets transiting stars less massive than this, and these will be the planets to characterize with JWST. Here, we propose to expand the MUSCLES project to: (a) new M dwarf exoplanet hosts with varying properties; (b) reference M dwarfs below 0.3 solar masses that may be used as proxies for M dwarf planet hosts discovered after HST's lifetime; and (c) more rapidly rotating stars of GJ1132's mass to probe XUV evolution over gigayear timescales. We propose to gather the first panchromatic SEDs of rocky planet hosts GJ1132 and Trappist-1. This proposal extends proven methods to a key new sample of stars, upon which critically depends the long-term goal of studying habitable planet atmospheres with JWST and beyond.

  18. Hemangiopericytoma/solitary fibrous tumor of pectoralis major muscle mimicking a breast mass

    PubMed Central

    Dragoumis, Dimitrios; Desiris, Klearchos; Kyropoulou, Aikaterini; Malandri, Maria; Assimaki, Anthoula; Tsiftsoglou, Aris

    2013-01-01

    INTRODUCTION Hemangiopericytoma (HPC)/solitary fibrous tumor (SFT) is a very uncommon tumor of uncertain malignant behavior. In 1942, Stout and Murray first characterized these neoplasms as “vascular tumors arising from Zimmerman's pericytes” and till now hemangiopericytomas and solitary fibrous tumors of the soft tissues are regarded as features of the same entity in the soft tissue fascicle. PRESENTATION OF CASE We present a case of hemangiopericytoma/solitary fibrous tumor of the pectoralis major muscle in a 33-year-old female. She first noticed a painless mass in her right breast. Ultrasound of the breast revealed a large heterogeneously hypoechoic lesion within the pectoralis major muscle. Fine needle aspiration of the tumor did not produce any meaningful result. The lesion was completely removed by surgical resection. Histologically, the tumor had staghorn-like vasculature and immunohistochemistry for CD34 was positive, whereas desmin, smooth-muscle actin, S-100 protein, cytokeratins (AE1/AE3) and epithelial membrane antigen (EMA) were all negative. A diagnosis of hemangiopericytoma/solitary fibrous tumor was rendered. DISCUSSION Tumors comprising the HPC/SFT spectrum represent a small subset of soft tissue sarcomas and are found virtually at any site in the body. Wide surgical resection can achieve favorable long-term survival. CONCLUSION Due to the rarity and unpredictable biological potential of these tumors, long-term follow-up is mandatory even after radical resection, because recurrence or development of metastasis may be delayed many years. PMID:23416503

  19. Human skeletal muscle biochemical diversity.

    PubMed

    Tirrell, Timothy F; Cook, Mark S; Carr, J Austin; Lin, Evie; Ward, Samuel R; Lieber, Richard L

    2012-08-01

    The molecular components largely responsible for muscle attributes such as passive tension development (titin and collagen), active tension development (myosin heavy chain, MHC) and mechanosensitive signaling (titin) have been well studied in animals but less is known about their roles in humans. The purpose of this study was to perform a comprehensive analysis of titin, collagen and MHC isoform distributions in a large number of human muscles, to search for common themes and trends in the muscular organization of the human body. In this study, 599 biopsies were obtained from six human cadaveric donors (mean age 83 years). Three assays were performed on each biopsy - titin molecular mass determination, hydroxyproline content (a surrogate for collagen content) and MHC isoform distribution. Titin molecular mass was increased in more distal muscles of the upper and lower limbs. This trend was also observed for collagen. Percentage MHC-1 data followed a pattern similar to collagen in muscles of the upper extremity but this trend was reversed in the lower extremity. Titin molecular mass was the best predictor of anatomical region and muscle functional group. On average, human muscles had more slow myosin than other mammals. Also, larger titins were generally associated with faster muscles. These trends suggest that distal muscles should have higher passive tension than proximal ones, and that titin size variability may potentially act to 'tune' the protein's mechanotransduction capability.

  20. Genes Whose Gain or Loss-Of-Function Increases Skeletal Muscle Mass in Mice: A Systematic Literature Review.

    PubMed

    Verbrugge, Sander A J; Schönfelder, Martin; Becker, Lore; Yaghoob Nezhad, Fakhreddin; Hrabě de Angelis, Martin; Wackerhage, Henning

    2018-01-01

    Skeletal muscle mass differs greatly in mice and humans and this is partially inherited. To identify muscle hypertrophy candidate genes we conducted a systematic review to identify genes whose experimental loss or gain-of-function results in significant skeletal muscle hypertrophy in mice. We found 47 genes that meet our search criteria and cause muscle hypertrophy after gene manipulation. They are from high to small effect size: Ski, Fst, Acvr2b, Akt1, Mstn, Klf10, Rheb, Igf1, Pappa, Ppard, Ikbkb, Fstl3, Atgr1a, Ucn3, Mcu, Junb, Ncor1, Gprasp1, Grb10, Mmp9, Dgkz, Ppargc1a (specifically the Ppargc1a4 isoform), Smad4, Ltbp4, Bmpr1a, Crtc2, Xiap, Dgat1, Thra, Adrb2, Asb15, Cast, Eif2b5, Bdkrb2, Tpt1, Nr3c1, Nr4a1, Gnas, Pld1, Crym, Camkk1, Yap1, Inhba, Tp53inp2, Inhbb, Nol3, Esr1 . Knock out, knock down, overexpression or a higher activity of these genes causes overall muscle hypertrophy as measured by an increased muscle weight or cross sectional area. The mean effect sizes range from 5 to 345% depending on the manipulated gene as well as the muscle size variable and muscle investigated. Bioinformatical analyses reveal that Asb15, Klf10, Tpt1 are most highly expressed hypertrophy genes in human skeletal muscle when compared to other tissues. Many of the muscle hypertrophy-regulating genes are involved in transcription and ubiquitination. Especially genes belonging to three signaling pathways are able to induce hypertrophy: (a) Igf1-Akt-mTOR pathway, (b) myostatin-Smad signaling, and (c) the angiotensin-bradykinin signaling pathway. The expression of several muscle hypertrophy-inducing genes and the phosphorylation of their protein products changes after human resistance and high intensity exercise, in maximally stimulated mouse muscle or in overloaded mouse plantaris.

  1. Resistance exercise-induced fluid shifts: change in active muscle size and plasma volume

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, L. L.; Convertino, V. A.; Dudley, G. A.

    1995-01-01

    The purpose of this study was to test the hypothesis that the reduction in plasma volume (PV) induced by resistance exercise reflects fluid loss to the extravascular space and subsequently selective increase in cross-sectional area (CSA) of active but not inactive skeletal muscle. We compared changes in active and inactive muscle CSA and PV after barbell squat exercise. Magnetic resonance imaging (MRI) was used to quantify muscle involvement in exercise and to determine CSA of muscle groups or individual muscles [vasti (VS), adductor (Add), hamstring (Ham), and rectus femoris (RF)]. Muscle involvement in exercise was determined using exercise-induced contrast shift in spin-spin relaxation time (T2)-weighted MR images immediately postexercise. Alterations in muscle size were based on the mean CSA of individual slices. Hematocrit, hemoglobin, and Evans blue dye were used to estimate changes in PV. Muscle CSA and PV data were obtained preexercise and immediately postexercise and 15 and 45 min thereafter. A hierarchy of muscle involvement in exercise was found such that VS > Add > Ham > RF, with the Ham and RF showing essentially no involvement. CSA of the VS and Add muscle groups were increased 10 and 5%, respectively, immediately after exercise in each thigh with no changes in Ham and RF CSA. PV was decreased 22% immediately following exercise. The absolute loss of PV was correlated (r2 = 0.75) with absolute increase in muscle CSA immediately postexercise, supporting the notion that increased muscle size after resistance exercise reflects primarily fluid movement from the vascular space into active but not inactive muscle.

  2. Genome-wide proteomics analysis on longissimus muscles in Qinchuan beef cattle.

    PubMed

    He, Hua; Chen, Si; Liang, Wei; Liu, Xiaolin

    2017-04-01

    To gain further insight into the molecular mechanism of bovine muscle development, we combined mass spectrometry characterization of proteins with Illumina deep sequencing of RNAs obtained from bovine longissimus muscle (LD) at prenatal and postnatal stages. For the proteomic study, each group of LD proteins was extracted and labeled using isobaric tags for relative and absolute quantitation (iTRAQ) method. Among the 1321 proteins identified from six samples, 390 proteins were differentially expressed in embryos at day 135 post-fertilization (Emb135d) vs. 30-month-old adult cattle (Emb135d vs. 30M) samples. Gene Ontology, Cluster of Orthologous Groups and Kyoto Encyclopedia of Genes and Genomes analyses were further conducted to better understand the different functions. Furthermore, we analyzed the relationship between transcript and protein regulation between samples by direct comparison of expression levels from transcriptomic and iTRAQ-based proteomics. Association results indicated that 1295 of 1321 proteins could be mapped to transcriptome sequencing data. This study provides the most comprehensive, targeted survey of bovine LD proteins to date and has shown the power of combining transcriptomic and proteomic approaches to provide molecular insights for understanding the developmental characteristics in bovine muscle, and even in other mammals. © 2016 Stichting International Foundation for Animal Genetics.

  3. Effects of obesity on lower extremity muscle function during walking at two speeds.

    PubMed

    Lerner, Zachary F; Board, Wayne J; Browning, Raymond C

    2014-03-01

    Walking is a recommended form of physical activity for obese adults, yet the effects of obesity and walking speed on the biomechanics of walking are not well understood. The purpose of this study was to examine joint kinematics, muscle force requirements and individual muscle contributions to the walking ground reaction forces (GRFs) at two speeds (1.25 ms(-1) and 1.50 ms(-1)) in obese and nonobese adults. Vasti (VAS), gluteus medius (GMED), gastrocnemius (GAST), and soleus (SOL) forces and their contributions to the GRFs were estimated using three-dimensional musculoskeletal models scaled to the anthropometrics of nine obese (35.0 (3.78 kg m(-2))); body mass index mean (SD)) and 10 nonobese (22.1 (1.02 kg m(-2))) subjects. The obese individuals walked with a straighter knee in early stance at the faster speed and greater pelvic obliquity during single limb support at both speeds. Absolute force requirements were generally greater in obese vs. nonobese adults, the main exception being VAS, which was similar between groups. At both speeds, lean mass (LM) normalized force output for GMED was greater in the obese group. Obese individuals appear to adopt a gait pattern that reduces VAS force output, especially at speeds greater than their preferred walking velocity. Greater relative GMED force requirements in obese individuals may contribute to altered kinematics and increased risk of musculoskeletal injury/pathology. Our results suggest that obese individuals may have relative weakness of the VAS and hip abductor muscles, specifically GMED, which may act to increase their risk of musculoskeletal injury/pathology during walking, and therefore may benefit from targeted muscle strengthening. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Differential sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy.

    PubMed

    de Theije, C C; Langen, R C J; Lamers, W H; Gosker, H R; Schols, A M W J; Köhler, S E

    2015-01-15

    Hypoxia as a consequence of acute and chronic respiratory disease has been associated with muscle atrophy. This study investigated the sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy. Male mice were exposed to 8% normobaric oxygen for up to 21 days. Oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles were isolated, weighed, and assayed for expression profiles of the ubiquitin-proteasome system (UPS), the autophagy-lysosome pathway (ALP), and glucocorticoid receptor (GR) and hypoxia-inducible factor-1α (HIF1α) signaling. Fiber-type composition and the capillary network were investigated. Hypoxia-induced muscle atrophy was more prominent in the EDL than the soleus muscle. Although increased expression of HIF1α target genes showed that both muscle types sensed hypoxia, their adaptive responses differed. Atrophy consistently involved a hypoxia-specific effect (i.e., not attributable to a hypoxia-mediated reduction of food intake) in the EDL only. Hypoxia-specific activation of the UPS and ALP and increased expression of the glucocorticoid receptor (Gr) and its target genes were also mainly observed in the EDL. In the soleus, stimulation of gene expression of those pathways could be mimicked to a large extent by food restriction alone. Hypoxia increased the number of capillary contacts per fiber cross-sectional area in both muscles. In the EDL, this was due to type II fiber atrophy, whereas in the soleus the absolute number of capillary contacts increased. These responses represent two distinct modes to improve oxygen supply to muscle fibers, but may aggravate muscle atrophy in chronic obstructive pulmonary disease patients who have a predominance of type II fibers. Copyright © 2015 the American Physiological Society.

  5. Transcutaneous calf-muscle electro-stimulation: A prospective treatment for diabetic claudicants?

    PubMed

    Ellul, Christian; Gatt, Alfred

    2016-11-01

    First-line therapy for claudicants with diabetes include supervised exercise programmes to improve walking distance. However, exercise comes with a number of barriers and may be contraindicated in certain conditions. The aim of this study was to evaluate whether calf-muscle electro-stimulation improves claudication distance. A prospective, one-group, pretest-posttest study design was employed on 40 participants living with type 2 diabetes mellitus, peripheral artery disease (ankle-brachial pressure index < 0.90) and calf-muscle claudication. Calf-muscle electro-stimulation of varying frequencies (1-250 Hz) was applied on both ischaemic limbs (N = 80) for 1 h per day for 12 consecutive weeks. The absolute claudication distance was measured at baseline and following the intervention. The cohort (n = 40; 30 males; mean age = 71 years; mean ankle-brachial pressure index = 0.70) registered a mean baseline absolute claudication distance of 333.71 m (standard deviation = 208). Following 91.68 days (standard deviation = 6.23) of electrical stimulation, a significant mean increase of 137 m (standard deviation = 136) in the absolute claudication distance was registered (p = 0.000, Wilcoxon signed rank test). Electrical stimulation of varying low to high frequencies on ischaemic calf muscles significantly increased the maximal walking capacity in claudicants with type 2 diabetes. This therapeutic approach may be considered in patients with impaired exercise tolerance or as an adjunct treatment modality. © The Author(s) 2016.

  6. Lack of independent effect of type 2 diabetes beyond characteristic comorbidities and medications on small muscle mass exercising muscle blood flow and exercise tolerance

    PubMed Central

    Poitras, Veronica J; Bentley, Robert F; Hopkins-Rosseel, Diana H; LaHaye, Stephen A; Tschakovsky, Michael E

    2015-01-01

    Persons with type 2 diabetes (T2D) are believed to have reduced exercise tolerance; this may be partly due to impaired exercising muscle blood flow (MBF). Whether there is an impact of T2D on exercising MBF within the typical constellation of comorbidities (hypertension, dyslipidemia, obesity) and their associated medications has not been investigated. We tested the hypothesis that small muscle mass exercise tolerance is reduced in persons with T2D versus Controls (matched for age, body mass index, fitness, comorbidities, non-T2D medications) and that this is related to blunted MBF. Eight persons with T2D and eight controls completed a forearm critical force (fCFimpulse) test as a measure of exercise tolerance (10-min intermittent maximal effort forearm contractions; the average contraction impulse in the last 30 sec quantified fCFimpulse). Forearm blood flow (FBF; ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured; forearm vascular conductance (FVK) was calculated. Data are means ± SD, T2D versus Control. fCFimpulse was not different between groups (136.9 ± 47.3  N·sec vs. 163.1 ± 49.7 N·sec, P = 0.371) nor was the ΔFBF from rest to during exercise at fCFimpulse (502.9 ± 144.6 vs. 709.1 ± 289.2 mL/min, P = 0.092), or its determinants ΔFVK and ΔMAP (both P > 0.05), although there was considerable interindividual variability. ΔFBF was strongly related to fCFimpulse (r = 0.727, P = 0.002), providing support for the relationship between oxygen delivery and exercise tolerance. We conclude that small muscle mass exercising MBF and exercise tolerance are not impaired in representative persons with T2D versus appropriately matched controls. This suggests that peripheral vascular control impairment does not contribute to reduced exercise tolerance in this population. PMID:26265750

  7. Mortality–Predictability of Body Size and Muscle Mass Surrogates in Asian versus Caucasian and African–American Hemodialysis Patients

    PubMed Central

    Park, Jongha; Jin, Dong Chan; Molnar, Miklos Z.; Dukkipati, Ramanath; Kim, Yong–Lim; Jing, Jennie; Levin, Nathan W.; Nissenson, Allen R.; Lee, Jong Soo; Kalantar–Zadeh, Kamyar

    2013-01-01

    OBJECTIVE Among chronic dialysis patients an obesity paradox or reverse epidemiology is known, but it is no clear whether the association of body size and muscle mass with survival is consistent across race, especially in East Asian versus Caucasian and African–American hemodialysis (HD) patients PATIENTS AND METHODS Using 20,818 HD patients in South Korea from February 1, 2001 to June 30, 2009 and 20,000 matched HD patients in the United States (10,000 Caucasians and 10,000 African–Americans) from July 1, 2001 to June 30, 2006, we compared mortality associations of baseline body mass index (BMI) and serum creatinine (Cr) level, as likely surrogates of obesity and muscle mass across the three races. RESULTS In Korean HD patients higher BMI together with higher serum Cr levels were associated with greater survival, as previously reported from US and European studies. In the matched cohort (n=10,000 in each of the three races), mortality risks were lower across higher BMI and serum Cr levels, and these association were similar in all three races (reference groups: patients with BMI >25.0 kg/m2 or serum Cr >12 mg/dL in each race). Patients with BMI level ≤18.5 kg/m2 (underweight) reported 78%, 79% and 57% higher mortality risk among Caucasian, African–American and Korean, respectively, and so did patients with serum Cr level ≤6.0 mg/dL, who reported 108%, 87% and 78% higher mortality, respectively. CONCLUSION Race does not modify the association of higher body size and muscle mass with greater survival in HD patients. Given consistency of the obesity paradox, which may be related to mitigated effect of protein–energy wasting on mortality irrespective of racial disparities, nutritional support to improve survival should be tested across all races of HD patients. PMID:23562348

  8. The Association between Parameters of Malnutrition and Diagnostic Measures of Sarcopenia in Geriatric Outpatients

    PubMed Central

    Reijnierse, Esmee M.; Trappenburg, Marijke C.; Leter, Morena J.; Blauw, Gerard Jan; de van der Schueren, Marian A. E.; Meskers, Carel G. M.; Maier, Andrea B.

    2015-01-01

    Objectives Diagnostic criteria for sarcopenia include measures of muscle mass, muscle strength and physical performance. Consensus on the definition of sarcopenia has not been reached yet. To improve insight into the most clinically valid definition of sarcopenia, this study aimed to compare the association between parameters of malnutrition, as a risk factor in sarcopenia, and diagnostic measures of sarcopenia in geriatric outpatients. Material and Methods This study is based on data from a cross-sectional study conducted in a geriatric outpatient clinic including 185 geriatric outpatients (mean age 82 years). Parameters of malnutrition included risk of malnutrition (assessed by the Short Nutritional Assessment Questionnaire), loss of appetite, unintentional weight loss and underweight (body mass index <22 kg/m2). Diagnostic measures of sarcopenia included relative muscle mass (lean mass and appendicular lean mass [ALM] as percentages), absolute muscle mass (total lean mass and ALM/height2), handgrip strength and walking speed. All diagnostic measures of sarcopenia were standardized. Associations between parameters of malnutrition (independent variables) and diagnostic measures of sarcopenia (dependent variables) were analysed using multivariate linear regression models adjusted for age, body mass, fat mass and height in separate models. Results None of the parameters of malnutrition was consistently associated with diagnostic measures of sarcopenia. The strongest associations were found for both relative and absolute muscle mass; less stronger associations were found for muscle strength and physical performance. Underweight (p = <0.001) and unintentional weight loss (p = 0.031) were most strongly associated with higher lean mass percentage after adjusting for age. Loss of appetite (p = 0.003) and underweight (p = 0.021) were most strongly associated with lower total lean mass after adjusting for age and fat mass. Conclusion Parameters of malnutrition relate

  9. Muscle Weakness Is Associated With an Increase of Left Ventricular Mass Through Excessive Blood Pressure Elevation During Exercise in Patients With Hypertension.

    PubMed

    Kamada, Yumi; Masuda, Takashi; Tanaka, Shinya; Akiyama, Ayako; Nakamura, Takeshi; Hamazaki, Nobuaki; Okubo, Michihito; Kobayashi, Naoyuki; Ako, Junya

    2017-08-03

    Autonomic imbalance in hypertension induces excessive blood pressure (BP) elevation during exercise, thereby increasing left ventricular mass (LVM). Although muscle weakness enhances autonomic imbalance by stimulating muscle sympathetic activity during exercise, it is unclear whether muscle weakness is associated with an increase of LVM in patients with hypertension. This study aimed to investigate the relationships between muscle weakness, BP elevation during exercise, and LVM in these patients. Eighty-six hypertensive patients aged 69 ± 8 years with controlled resting BP (ie, < 140/90 mmHg) were recruited. Plasma brain natriuretic peptide (BNP), left ventricular mass index (LVMI), and knee extension muscle strength were measured. Changes in plasma noradrenaline (NORA) and brachial-ankle pulse wave velocity (ba-PWV) were assessed before and after an ergometer exercise test performed at moderate intensity (ΔNORA and ΔPWV, respectively). A difference between baseline and peak systolic BP during the exercise test was defined as BP elevation during exercise (ΔSBP). Relationships between muscle strength, ΔNORA, ΔPWV, ΔSBP, BNP, and LVMI were analyzed, and significant factors increasing LVM were identified using univariate and multivariate regression analyses. Muscle strength was negatively correlated with ΔNORA (r = -0.202, P = 0.048), ΔPWV (r = -0.328, P = 0.002), ΔSBP (r = -0.230, P = 0.033), BNP (r = -0.265, P = 0.014), and LVMI (r = -0.233, P = 0.031). LVMI was positively correlated with ΔPWV (r = 0.246, P = 0.023) and ΔSBP (r = 0.307, P = 0.004). Muscle strength was a significant independent factor associated with LVMI (β = -0.331, P = 0.010). Our findings suggest that muscle weakness is associated with an increase of LVM through excessive BP elevation during exercise in patients with hypertension.

  10. Partial Reductions in Mechanical Loading Yield Proportional Changes in Bone Density, Bone Architecture, and Muscle Mass

    PubMed Central

    Ellman, Rachel; Spatz, Jordan; Cloutier, Alison; Palme, Rupert; Christiansen, Blaine A; Bouxsein, Mary L

    2014-01-01

    Although the musculoskeletal system is known to be sensitive to changes in its mechanical environment, the relationship between functional adaptation and below-normal mechanical stimuli is not well defined. We investigated bone and muscle adaptation to a range of reduced loading using the partial weight suspension (PWS) system, in which a two-point harness is used to offload a tunable amount of body weight while maintaining quadrupedal locomotion. Skeletally mature female C57Bl/6 mice were exposed to partial weight bearing at 20%, 40%, 70%, or 100% of body weight for 21 days. A hindlimb unloaded (HLU) group was included for comparison in addition to age-matched controls in normal housing. Gait kinematics was measured across the full range of weight bearing, and some minor alterations in gait from PWS were identified. With PWS, bone and muscle changes were generally proportional to the degree of unloading. Specifically, total body and hindlimb bone mineral density, calf muscle mass, trabecular bone volume of the distal femur, and cortical area of the femur midshaft were all linearly related to the degree of unloading. Even a load reduction to 70% of normal weight bearing was associated with significant bone deterioration and muscle atrophy. Weight bearing at 20% did not lead to better bone outcomes than HLU despite less muscle atrophy and presumably greater mechanical stimulus, requiring further investigation. These data confirm that the PWS model is highly effective in applying controllable, reduced, long-term loading that produces predictable, discrete adaptive changes in muscle and bone of the hindlimb. PMID:23165526

  11. Specific Adaptations in Performance and Muscle Architecture After Weighted Jump-Squat vs. Body Mass Squat Jump Training in Recreational Soccer Players.

    PubMed

    Coratella, Giuseppe; Beato, Marco; Milanese, Chiara; Longo, Stefano; Limonta, Eloisa; Rampichini, Susanna; Cè, Emiliano; Bisconti, Angela V; Schena, Federico; Esposito, Fabio

    2018-04-01

    Coratella, G, Beato, M, Milanese, C, Longo, S, Limonta, E, Rampichini, S, Cè, E, Bisconti, AV, Schena, F, and Esposito, F. Specific adaptations in performance and muscle architecture after weighted jump-squat vs. body mass squat jump training in recreational soccer players. J Strength Cond Res 32(4): 921-929, 2018-The aim of the present study was to compare the effects of weighted jump-squat training (WJST) vs. body mass squat jump training (BMSJT) on quadriceps' muscle architecture, lower-limb lean-mass (LM) and muscle strength, performance in change of direction (COD), and sprint and jump in recreational soccer players. Forty-eight healthy soccer players participated in an offseason randomized controlled trial. Before and after an 8-week training intervention, vastus lateralis pennation angle, fascicle length, muscle thickness, LM, squat 1RM, quadriceps and hamstrings isokinetic peak torque, agility T-test, 10-and 30-m sprints, and squat-jump (SJ) were measured. Although similar increases were observed in muscle thickness, fascicle length increased more in WJST (Effect size [ES] = 1.18, 0.82-1.54) than in BMSJT (ES = 0.54, 0.40-0.68), and pennation angle increased only in BMSJT (ES = 1.03, 0.78-1.29). Greater increases in LM were observed in WJST (ES = 0.44, 0.29-0.59) than in BMSJT (ES = 0.21, 0.07-0.37). The agility T-test (ES = 2.95, 2.72-3.18), 10-m (ES = 0.52, 0.22-0.82), and 30-m sprints (ES = 0.52, 0.23-0.81) improved only in WJST, whereas SJ improved in BMSJT (ES = 0.89, 0.43-1.35) more than in WJST (ES = 0.30, 0.03-0.58). Similar increases in squat 1RM and peak torque occurred in both groups. The greater inertia accumulated within the landing phase in WJST vs. BMSJT has increased the eccentric workload, leading to specific eccentric-like adaptations in muscle architecture. The selective improvements in COD in WJST may be related to the increased braking ability generated by the enhanced eccentric workload.

  12. Soleus muscles of SAMP8 mice provide an accelerated model of skeletal muscle senescence.

    PubMed

    Derave, Wim; Eijnde, Bert O; Ramaekers, Monique; Hespel, Peter

    2005-07-01

    Animal models are valuable research tools towards effective prevention of sarcopenia and towards a better understanding of the mechanisms underlying skeletal muscle aging. We investigated whether senescence-accelerated mouse (SAM) strains provide valid models for skeletal muscle aging studies. Male senescence-prone mice SAMP6 and SAMP8 were studied at age 10, 25 and 60 weeks and compared with senescence-resistant strain, SAMR1. Soleus and EDL muscles were tested for in vitro contractile properties, phosphocreatine content, muscle mass and fiber-type distribution. Declined muscle mass and contractility were observed at 60 weeks, the differences being more pronounced in SAMP8 than SAMP6 and more pronounced in soleus than EDL. Likewise, age-related decreases in muscle phosphocreatine content and type-II fiber size were most pronounced in SAMP8 soleus. In conclusion, typical features of muscular senescence occur at relatively young age in SAMP8 and nearly twice as fast as compared with other models. We suggest that soleus muscles of SAMP8 mice provide a cost-effective model for muscular aging studies.

  13. Universal absolute quantification of biomolecules using element mass spectrometry and generic standards.

    PubMed

    Calderón-Celis, Francisco; Sanz-Medel, Alfredo; Encinar, Jorge Ruiz

    2018-01-23

    We present a novel and highly sensitive ICP-MS approach for absolute quantification of all important target biomolecule containing P, S, Se, As, Br, and/or I (e.g., proteins and phosphoproteins, metabolites, pesticides, drugs), under the same simple instrumental conditions and without requiring any specific and/or isotopically enriched standard.

  14. Agonist muscle adaptation accompanied by antagonist muscle atrophy in the hindlimb of mice following stretch-shortening contraction training.

    PubMed

    Rader, Erik P; Naimo, Marshall A; Ensey, James; Baker, Brent A

    2017-02-02

    The vast majority of dynamometer-based animal models for investigation of the response to chronic muscle contraction exposure has been limited to analysis of isometric, lengthening, or shortening contractions in isolation. An exception to this has been the utilization of a rat model to study stretch-shortening contractions (SSCs), a sequence of consecutive isometric, lengthening, and shortening contractions common during daily activity and resistance-type exercise. However, the availability of diverse genetic strains of rats is limited. Therefore, the purpose of the present study was to develop a dynamometer-based SSC training protocol to induce increased muscle mass and performance in plantarflexor muscles of mice. Young (3 months old) C57BL/6 mice were subjected to 1 month of plantarflexion SSC training. Hindlimb muscles were analyzed for muscle mass, quantitative morphology, myogenesis/myopathy relevant gene expression, and fiber type distribution. The main aim of the research was achieved when training induced a 2-fold increase in plantarflexion peak torque output and a 19% increase in muscle mass for the agonist plantaris (PLT) muscle. In establishing this model, several outcomes emerged which raised the value of the model past that of being a mere recapitulation of the rat model. An increase in the number of muscle fibers per transverse muscle section accounted for the PLT muscle mass gain while the antagonist tibialis anterior (TA) muscle atrophied by 30% with preferential atrophy of type IIb and IIx fibers. These alterations were accompanied by distinct gene expression profiles. The findings confirm the development of a stretch-shortening contraction training model for the PLT muscle of mice and demonstrate that increased cross-sectional fiber number can occur following high-intensity SSC training. Furthermore, the TA muscle atrophy provides direct evidence for the concept of muscle imbalance in phasic non-weight bearing muscles, a concept largely

  15. Human skeletal muscle biochemical diversity

    PubMed Central

    Tirrell, Timothy F.; Cook, Mark S.; Carr, J. Austin; Lin, Evie; Ward, Samuel R.; Lieber, Richard L.

    2012-01-01

    SUMMARY The molecular components largely responsible for muscle attributes such as passive tension development (titin and collagen), active tension development (myosin heavy chain, MHC) and mechanosensitive signaling (titin) have been well studied in animals but less is known about their roles in humans. The purpose of this study was to perform a comprehensive analysis of titin, collagen and MHC isoform distributions in a large number of human muscles, to search for common themes and trends in the muscular organization of the human body. In this study, 599 biopsies were obtained from six human cadaveric donors (mean age 83 years). Three assays were performed on each biopsy – titin molecular mass determination, hydroxyproline content (a surrogate for collagen content) and MHC isoform distribution. Titin molecular mass was increased in more distal muscles of the upper and lower limbs. This trend was also observed for collagen. Percentage MHC-1 data followed a pattern similar to collagen in muscles of the upper extremity but this trend was reversed in the lower extremity. Titin molecular mass was the best predictor of anatomical region and muscle functional group. On average, human muscles had more slow myosin than other mammals. Also, larger titins were generally associated with faster muscles. These trends suggest that distal muscles should have higher passive tension than proximal ones, and that titin size variability may potentially act to ‘tune’ the protein's mechanotransduction capability. PMID:22786631

  16. Skeletal muscle mass to visceral fat area ratio is an important determinant affecting hepatic conditions of non-alcoholic fatty liver disease.

    PubMed

    Shida, Takashi; Akiyama, Kentaro; Oh, Sechang; Sawai, Akemi; Isobe, Tomonori; Okamoto, Yoshikazu; Ishige, Kazunori; Mizokami, Yuji; Yamagata, Kenji; Onizawa, Kojiro; Tanaka, Hironori; Iijima, Hiroko; Shoda, Junichi

    2018-04-01

    Not only obesity but also sarcopenia is associated with NAFLD. The influence of altered body composition on the pathophysiology of NAFLD has not been fully elucidated. The aim of this study is to determine whether skeletal muscle mass to visceral fat area ratio (SV ratio) affects NAFLD pathophysiology. A total of 472 subjects were enrolled. The association between SV ratio and NAFLD pathophysiological factors was assessed in a cross-sectional nature by stratification analysis. When the SV ratio was stratified by quartiles (Q 1 -Q 4 ), the SV ratio showed a negative relationship with the degree of body mass index, HOMA-IR, and liver stiffness (Q 1 , 8.9 ± 7.5 kPa, mean ± standard deviation; Q 2 , 7.5 ± 6.2; Q 3 , 5.8 ± 3.7; Q 4 , 5.0 ± 1.9) and steatosis (Q 1 , 282 ± 57 dB/m; Q 2 , 278 ± 58; Q 3 , 253 ± 57; Q 4 , 200 ± 42) measured by transient elastography. Levels of leptin and biochemical markers of liver cell damage, liver fibrosis, inflammation and oxidative stress, and hepatocyte apoptosis were significantly higher in subjects in Q 1 than in those in Q 2 , Q 3 , or Q 4 . Moreover, fat contents in femoral muscles were significantly higher in subjects in Q 1 and the change was associated with weakened muscle strength. In logistic regression analysis, NAFLD subjects with the decreased SV ratio were likely to have an increased risk of moderate-to-severe steatosis and that of advanced fibrosis. Decreased muscle mass coupled with increased visceral fat mass is closely associated with an increased risk for exacerbating NAFLD pathophysiology.

  17. Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes

    PubMed Central

    Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

    2017-01-01

    Background: Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. Objective: To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. Materials and Methods: We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Results: Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. Conclusion: These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. SUMMARY Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation.Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus

  18. Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes.

    PubMed

    Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

    2017-01-01

    Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation. Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus L. flower absolute Abbreviations used: HSF: Hibiscus syriacus L. flower

  19. Longitudinal Changes in AbsoluteVO2peak, Physical Activity Level, Body Mass Index, and Overweightedness among Adolescents in Vocational and Non-Vocational Studies

    PubMed Central

    Lagestad, Pål; Floan, Oddbjørn; Moa, Ivar Fossland

    2017-01-01

    The purpose of the study was to examine differences in physical activity level, physical fitness, body mass index, and overweight among adolescents in vocational and non-vocational studies, at the age of 14, 16, and 19, using a 5-year longitudinal design. Students in sport studies had the highest absoluteVO2peak and higher physical activity levels, than students in vocational subjects and students with a specialization in general studies. However, there were no significant differences between students in vocational subjects and students with a specialization in general studies according to absoluteVO2peak and physical activity levels. Students in vocational subjects were significantly more overweight/obese at 19 years of age, compared with the other students. Our findings support previous research pointing to overweightedness as being more widespread among adolescents in vocational programs than in non-vocational programs. However, differences in the physical activity level and physical fitness do not seem to explain these differences. PMID:28871279

  20. Powerful signals for weak muscles.

    PubMed

    Saini, Amarjit; Faulkner, Steve; Al-Shanti, Nasser; Stewart, Claire

    2009-10-01

    The aim of the present review is to summarise, evaluate and critique the different mechanisms involved in anabolic growth of skeletal muscle and the catabolic processes involved in cancer cachexia and sarcopenia of ageing. This is highly relevant, since they represent targets for future promising clinical investigations. Sarcopenia is an inevitable process associated with a gradual reduction in muscle mass and strength, associated with a reduction in motor unit number and atrophy of muscle fibres, especially the fast type IIa fibres. The loss of muscle mass with ageing is clinically important because it leads to diminished functional ability and associated complications. Cachexia is widely recognised as severe and rapid wasting accompanying disease states such as cancer or immunodeficiency disease. One of the main characteristics of cancer cachexia is asthenia or lack of strength, which is directly related to the muscle loss. Indeed, apart from the speed of loss, muscle wasting during cancer and ageing share many common metabolic pathways and mediators. In healthy young individuals, muscles maintain their mass and function because of a balance between protein synthesis and protein degradation associated with rates of anabolic and catabolic processes, respectively. Muscles grow (hypertrophy) when protein synthesis exceeds protein degradation. Conversely, muscles shrink (atrophy) when protein degradation dominates. These processes are not occurring independently of each other, but are finely coordinated by a web of intricate signalling networks. Such signalling networks are in charge of executing environmental and cellular cues that ultimately determine whether muscle proteins are synthesised or degraded. Increasing our understanding for the pathways involved in hypertrophy and atrophy and particularly the interaction of these pathways is essential in designing therapeutic strategies for both prevention and treatment of muscle wasting conditions with age and with

  1. Muscle-specific androgen receptor deletion shows limited actions in myoblasts but not in myofibers in different muscles in vivo.

    PubMed

    Rana, Kesha; Chiu, Maria W S; Russell, Patricia K; Skinner, Jarrod P; Lee, Nicole K L; Fam, Barbara C; Zajac, Jeffrey D; MacLean, Helen E

    2016-08-01

    The aim of this study was to investigate the direct muscle cell-mediated actions of androgens by comparing two different mouse lines. The cre-loxP system was used to delete the DNA-binding activity of the androgen receptor (AR) in mature myofibers (MCK mAR(ΔZF2)) in one model and the DNA-binding activity of the AR in both proliferating myoblasts and myofibers (α-actin mAR(ΔZF2)) in another model. We found that hind-limb muscle mass was normal in MCK mAR(ΔZF2) mice and that relative mass of only some hind-limb muscles was reduced in α-actin mAR(ΔZF2) mice. This suggests that myoblasts and myofibers are not the major cellular targets mediating the anabolic actions of androgens on male muscle during growth and development. Levator ani muscle mass was decreased in both mouse lines, demonstrating that there is a myofiber-specific effect in this unique androgen-dependent muscle. We found that the pattern of expression of genes including c-myc, Fzd4 and Igf2 is associated with androgen-dependent changes in muscle mass; therefore, these genes are likely to be mediators of anabolic actions of androgens. Further research is required to identify the major targets of androgen actions in muscle, which are likely to include indirect actions via other tissues. © 2016 Society for Endocrinology.

  2. Commercial golf glove effects on golf performance and forearm muscle activity.

    PubMed

    Sorbie, Graeme G; Darroch, Paul; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike C

    2017-01-01

    The study aimed to determine whether or not commercial golf gloves influence performance variables and forearm muscle activity during golf play. Fifteen golfers participated in the laboratory based study, each performing 8 golf swings with a Driver and 7-iron whilst wearing a glove and 8 without wearing the glove. Club head speed, ball speed and absolute carry distance performance variables were calculated. Surface electromyography was recorded from the flexor digitorum superficialis and extensor carpi radialis brevis on both forearm muscles. Club head speed, ball speed and absolute carry distance was significantly higher when using the Driver with the glove in comparison to the Driver without the glove (p < 0.05). No significant differences were evident when using the 7-iron and no significant differences were displayed in muscle activity in either of the conditions. Findings from this study suggest that driving performance is improved when wearing a glove.

  3. Feasibility of resistance training in adult McArdle patients: clinical outcomes and muscle strength and mass benefits.

    PubMed

    Santalla, Alfredo; Munguía-Izquierdo, Diego; Brea-Alejo, Lidia; Pagola-Aldazábal, Itziar; Díez-Bermejo, Jorge; Fleck, Steven J; Ara, Ignacio; Lucia, Alejandro

    2014-01-01

    We analyzed the effects of a 4-month resistance (weight lifting) training program followed by a 2-month detraining period in 7 adult McArdle patients (5 female) on: muscle mass (assessed by DXA), strength, serum creatine kinase (CK) activity and clinical severity. Adherence to training was ≥84% in all patients and no major contraindication or side effect was noted during the training or strength assessment sessions. The training program had a significant impact on total and lower extremities' lean mass (P < 0.05 for the time effect), with mean values increasing with training by +855 g (95% confidence interval (CI): 30, 1679) and +547 g (95%CI: 116, 978), respectively, and significantly decreasing with detraining. Body fat showed no significant changes over the study period. Bench press and half-squat performance, expressed as the highest value of average muscle power (W) or force (N) in the concentric-repetition phase of both tests showed a consistent increase over the 4-month training period, and decreased with detraining. Yet muscle strength and power detraining values were significantly higher than pre-training values, indicating that a training effect was still present after detraining. Importantly, all the participants, with no exception, showed a clear gain in muscle strength after the 4-month training period, e.g., bench press: +52 W (95% CI: 13, 91); half-squat: +173 W (95% CI: 96, 251). No significant time effect (P > 0.05) was noted for baseline or post strength assessment values of serum CK activity, which remained essentially within the range reported in our laboratory for McArdle patients. All the patients changed to a lower severity class with training, such that none of them were in the highest disease severity class (3) after the intervention and, as such, they did not have fixed muscle weakness after training. Clinical improvements were retained, in all but one patient, after detraining, such that after detraining all patients were classed as

  4. Autologous Minced Muscle Grafts: A Tissue Engineering Therapy for the Volumetric Loss of Skeletal Muscle

    DTIC Science & Technology

    2013-07-24

    report that over the first 16 wk postinjury, MG transplantation 1) promotes remarkable regeneration of innervated muscle fibers within the defect area...i.e., de novo muscle fiber regeneration); 2) reduced evidence of chronic injury in the remaining muscle mass compared with nonrepaired muscles ...cated nuclei in 30% of fibers observed in nonrepaired muscles ); and 3) significantly improves net torque production (i.e., 55% of the functional deficit

  5. Contrarily to whey and high protein diets, dietary free leucine supplementation cannot reverse the lack of recovery of muscle mass after prolonged immobilization during ageing.

    PubMed

    Magne, Hugues; Savary-Auzeloux, Isabelle; Migné, Carole; Peyron, Marie-Agnès; Combaret, Lydie; Rémond, Didier; Dardevet, Dominique

    2012-04-15

    During ageing, immobilization periods increase and are partially responsible of sarcopaenia by inducing a muscle atrophy which is hardly recovered from. Immobilization-induced atrophy is due to an increase of muscle apoptotic and proteolytic processes and decreased protein synthesis. Moreover, previous data suggested that the lack of muscle mass recovery might be due to a defect in protein synthesis response during rehabilitation. This study was conducted to explore protein synthesis during reloading and leucine supplementation effect as a nutritional strategy for muscle recovery. Old rats (22–24 months old) were subjected to unilateral hindlimb casting for 8 days (I8) and allowed to recover for 10–40 days (R10–R40). They were fed a casein (±leucine) diet during the recovery. Immobilized gastrocnemius muscles atrophied by 20%, and did not recover even at R40. Amount of polyubiquitinated conjugates and chymotrypsin- and trypsin-like activities of the 26S proteasome increased. These changes paralleled an ‘anabolic resistance' of the protein synthesis at the postprandial state (decrease of protein synthesis, P-S6 and P-4E-BP1). During the recovery, proteasome activities remained elevated until R10 before complete normalization and protein synthesis was slightly increased. With free leucine supplementation during recovery, if proteasome activities were normalized earlier and protein synthesis was higher during the whole recovery, it nevertheless failed in muscle mass gain. This discrepancy could be due to a ‘desynchronization' between the leucine signal and the availability of amino acids coming from casein digestion. Thus, when supplemented with leucine-rich proteins (i.e. whey) and high protein diets, animals partially recovered the muscle mass loss.

  6. Contrarily to whey and high protein diets, dietary free leucine supplementation cannot reverse the lack of recovery of muscle mass after prolonged immobilization during ageing

    PubMed Central

    Magne, Hugues; Savary-Auzeloux, Isabelle; Migné, Carole; Peyron, Marie-Agnès; Combaret, Lydie; Rémond, Didier; Dardevet, Dominique

    2012-01-01

    During ageing, immobilization periods increase and are partially responsible of sarcopaenia by inducing a muscle atrophy which is hardly recovered from. Immobilization-induced atrophy is due to an increase of muscle apoptotic and proteolytic processes and decreased protein synthesis. Moreover, previous data suggested that the lack of muscle mass recovery might be due to a defect in protein synthesis response during rehabilitation. This study was conducted to explore protein synthesis during reloading and leucine supplementation effect as a nutritional strategy for muscle recovery. Old rats (22–24 months old) were subjected to unilateral hindlimb casting for 8 days (I8) and allowed to recover for 10–40 days (R10–R40). They were fed a casein (±leucine) diet during the recovery. Immobilized gastrocnemius muscles atrophied by 20%, and did not recover even at R40. Amount of polyubiquitinated conjugates and chymotrypsin- and trypsin-like activities of the 26S proteasome increased. These changes paralleled an ‘anabolic resistance’ of the protein synthesis at the postprandial state (decrease of protein synthesis, P-S6 and P-4E-BP1). During the recovery, proteasome activities remained elevated until R10 before complete normalization and protein synthesis was slightly increased. With free leucine supplementation during recovery, if proteasome activities were normalized earlier and protein synthesis was higher during the whole recovery, it nevertheless failed in muscle mass gain. This discrepancy could be due to a ‘desynchronization’ between the leucine signal and the availability of amino acids coming from casein digestion. Thus, when supplemented with leucine-rich proteins (i.e. whey) and high protein diets, animals partially recovered the muscle mass loss. PMID:22351629

  7. Investigate methods for measuring muscle and bone mass changes in astronauts and animals which occur during space flight

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1977-01-01

    Sodium-22 is being used as a tracer for bone mineral metabolism studies. Dogs are being grown from puppies to adulthood on a diet containing a constant level of sodium-22 in order to uniformly tag the entire skeleton with a long lived radionuclide. This study is still in progress and the dogs are still growing. Potassium-40 measurements were made on people, who are replacing muscle mass lost due to leg injuries, in a second study. It appears that potassium-40 measurements provide an accurate and convenient method for determining relative changes in the muscle content of the leg.

  8. An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass.

    PubMed

    Asahara, Ryota; Endo, Kana; Liang, Nan; Matsukawa, Kanji

    2018-05-31

    We have reported using near-infrared spectroscopy that an increase in prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the exercise effort-dependent cardiovascular responses. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation in 13 subjects. The subjects performed one- or two-legged cycling at various relative intensities for 1 min. The prefrontal Oxy-Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one- and two-legged cycling were augmented in proportion to exercise intensity and muscle mass recruitment. The prefrontal Oxy-Hb increased at the start of voluntary cycling, while such increase was not developed during passive cycling. Mental imagery of cycling also increased the prefrontal Oxy-Hb, concomitantly with peripheral muscle vasodilatation. However, the increase in prefrontal Oxy-Hb at the start of voluntary cycling seemed independent of exercise intensity and muscle mass recruitment. It is likely that the increased prefrontal activity at the start of cycling exercise is not representative of the final output signal of central command itself toward the autonomic nervous system but may trigger neuronal activity in the caudal brain responsible for the generation of central command.

  9. Green tea extract attenuates muscle loss and improves muscle function during disuse, but fails to improve muscle recovery following unloading in aged rats

    PubMed Central

    Bennett, Brian T.; Wilson, Joseph C.; Sperringer, Justin; Mohamed, Junaith S.; Edens, Neile K.; Pereira, Suzette L.

    2014-01-01

    In this study we tested the hypothesis that green tea extract (GTE) would improve muscle recovery after reloading following disuse. Aged (32 mo) Fischer 344 Brown Norway rats were randomly assigned to receive either 14 days of hindlimb suspension (HLS) or 14 days of HLS followed by normal ambulatory function for 14 days (recovery). Additional animals served as cage controls. The rats were given GTE (50 mg/kg body wt) or water (vehicle) by gavage 7 days before and throughout the experimental periods. Compared with vehicle treatment, GTE significantly attenuated the loss of hindlimb plantaris muscle mass (−24.8% vs. −10.7%, P < 0.05) and tetanic force (−43.7% vs. −25.9%, P <0.05) during HLS. Although GTE failed to further improve recovery of muscle function or mass compared with vehicle treatment, animals given green tea via gavage maintained the lower losses of muscle mass that were found during HLS (−25.2% vs. −16.0%, P < 0.05) and force (−45.7 vs. −34.4%, P < 0.05) after the reloading periods. In addition, compared with vehicle treatment, GTE attenuated muscle fiber cross-sectional area loss in both plantaris (−39.9% vs. −23.9%, P < 0.05) and soleus (−37.2% vs. −17.6%) muscles after HLS. This green tea-induced difference was not transient but was maintained over the reloading period for plantaris (−45.6% vs. −21.5%, P <0.05) and soleus muscle fiber cross-sectional area (−38.7% vs. −10.9%, P <0.05). GTE increased satellite cell proliferation and differentiation in plantaris and soleus muscles during recovery from HLS compared with vehicle-treated muscles and decreased oxidative stress and abundance of the Bcl-2-associated X protein (Bax), yet this did not further improve muscle recovery in reloaded muscles. These data suggest that muscle recovery following disuse in aging is complex. Although satellite cell proliferation and differentiation are critical for muscle repair to occur, green tea-induced changes in satellite cell number is

  10. Green tea extract attenuates muscle loss and improves muscle function during disuse, but fails to improve muscle recovery following unloading in aged rats.

    PubMed

    Alway, Stephen E; Bennett, Brian T; Wilson, Joseph C; Sperringer, Justin; Mohamed, Junaith S; Edens, Neile K; Pereira, Suzette L

    2015-02-01

    In this study we tested the hypothesis that green tea extract (GTE) would improve muscle recovery after reloading following disuse. Aged (32 mo) Fischer 344 Brown Norway rats were randomly assigned to receive either 14 days of hindlimb suspension (HLS) or 14 days of HLS followed by normal ambulatory function for 14 days (recovery). Additional animals served as cage controls. The rats were given GTE (50 mg/kg body wt) or water (vehicle) by gavage 7 days before and throughout the experimental periods. Compared with vehicle treatment, GTE significantly attenuated the loss of hindlimb plantaris muscle mass (-24.8% vs. -10.7%, P < 0.05) and tetanic force (-43.7% vs. -25.9%, P <0.05) during HLS. Although GTE failed to further improve recovery of muscle function or mass compared with vehicle treatment, animals given green tea via gavage maintained the lower losses of muscle mass that were found during HLS (-25.2% vs. -16.0%, P < 0.05) and force (-45.7 vs. -34.4%, P < 0.05) after the reloading periods. In addition, compared with vehicle treatment, GTE attenuated muscle fiber cross-sectional area loss in both plantaris (-39.9% vs. -23.9%, P < 0.05) and soleus (-37.2% vs. -17.6%) muscles after HLS. This green tea-induced difference was not transient but was maintained over the reloading period for plantaris (-45.6% vs. -21.5%, P <0.05) and soleus muscle fiber cross-sectional area (-38.7% vs. -10.9%, P <0.05). GTE increased satellite cell proliferation and differentiation in plantaris and soleus muscles during recovery from HLS compared with vehicle-treated muscles and decreased oxidative stress and abundance of the Bcl-2-associated X protein (Bax), yet this did not further improve muscle recovery in reloaded muscles. These data suggest that muscle recovery following disuse in aging is complex. Although satellite cell proliferation and differentiation are critical for muscle repair to occur, green tea-induced changes in satellite cell number is by itself insufficient to

  11. Volumetric muscle loss injury repair using in situ fibrin gel cast seeded with muscle-derived stem cells (MDSCs)

    PubMed Central

    Matthias, Nadine; Hunt, Samuel D.; Wu, Jianbo; Lo, Jonathan; Smith Callahan, Laura A.; Li, Yong; Huard, Johnny; Darabi, Radbod

    2018-01-01

    Volumetric muscle defect, caused by trauma or combat injuries, is a major health concern leading to severe morbidity. It is characterized by partial or full thickness loss of muscle and its bio-scaffold, resulting in extensive fibrosis and scar formation. Therefore, the ideal therapeutic option is to use stem cells combined with bio-scaffolds to restore muscle. For this purpose, muscle-derived stem cells (MDSCs) are a great candidate due to their unique multi-lineage differentiation potential. In this study, we evaluated the regeneration potential of MDSCs for muscle loss repair using a novel in situ fibrin gel casting. Muscle defect was created by a partial thickness wedge resection in the tibialis anterior (TA)muscles of NSG mice which created an average of 25% mass loss. If untreated, this defect leads to severe muscle fibrosis. Next, MDSCs were delivered using a novel in situ fibrin gel casting method. Our results demonstrated MDSCs are able to engraft and form new myofibers in the defect when casted along with fibrin gel. LacZ labeled MDSCs were able to differentiate efficiently into new myofibers and significantly increase muscle mass. This was also accompanied by significant reduction of fibrotic tissue in the engrafted muscles. Furthermore, transplanted cells also contributed to new vessel formation and satellite cell seeding. These results confirmed the therapeutic potential of MDSCs and feasibility of direct in situ casting of fibrin/MDSC mixture to repair muscle mass defects. PMID:29331939

  12. Altered fibre types in gastrocnemius muscle of high wheel-running selected mice with mini-muscle phenotypes.

    PubMed

    Guderley, Helga; Joanisse, Denis R; Mokas, Sophie; Bilodeau, Geneviève M; Garland, Theodore

    2008-03-01

    Selective breeding of mice for high voluntary wheel running has favoured characteristics that facilitate sustained, aerobically supported activity, including a "mini-muscle" phenotype with markedly reduced hind limb muscle mass, increased mass-specific activities of oxidative enzymes, decreased % myosin heavy chain IIb, and, in the medial gastrocnemius, reduced twitch speed, reduced mass-specific isotonic power, and increased fatigue resistance. To evaluate whether selection has altered fibre type expression in mice with either "mini" or normal muscle phenotypes, we examined fibre types of red and white gastrocnemius. In both the medial and lateral gastrocnemius, the mini-phenotype increased activities of oxidative enzymes and decreased activities of glycolytic enzymes. In red muscle samples, the mini-phenotype markedly changed fibre types, with the % type I and type IIA fibres and the surface area of type IIA fibres increasing; in addition, mice from selected lines in general had an increased % type IIA fibres and larger type I fibres as compared with mice from control lines. White muscle samples from mini-mice showed dramatic structural alterations, with an atypical distribution of extremely small, unidentifiable fibres surrounded by larger, more oxidative fibres than normally present in white muscle. The increased proportion of oxidative fibres and these atypical small fibres together may explain the reduced mass and increased mitochondrial enzyme activities in mini-muscles. These and previous results demonstrate that extension of selective breeding beyond the time when the response of the selected trait (i.e. distance run) has levelled off can still modify the mechanistic underpinnings of this behaviour.

  13. Identifying Low Muscle Mass in Patients with Hip Fracture: Validation of Biolectrical Impedance Analysis and Anthropometry Compared to Dual Energy X-ray Absorptiometry.

    PubMed

    Steihaug, O M; Gjesdal, C G; Bogen, B; Ranhoff, A H

    2016-01-01

    Older hip fracture patients often have reduced muscle mass, which is associated with adverse outcomes. Dual energy X-ray absorptiometry (DXA) can determine muscle mass, but is not practical in the acute phase. We investigated bioelectrical impedance analysis (BIA) and anthropometry compared against DXA for detecting low muscle mass in hip fracture patients. This was a cross-sectional validation study at two Norwegian hospitals on 162 hip fracture patients aged ≥ 65 years. Appendicular lean mass (ALM) was determined by DXA, BIA and anthropometry 3 months after hip fracture. ALM by BIA was calculated by the Kyle, Janssen, Tengvall and Sergi equations, and ALM by anthropometry by the Heymsfield and Villani equations. The area under the receiver operating characteristic curve (AUC) was used to compare BIA and anthropometry for determining low ALM (≤5.67 kg/m2 for women and ≤7.25kg/m2 for men). Mean age was 79 years (SD 7.9), 74% were female. Mean ALM by DXA was 14.8 kg (SD 2.3) for women and 20.8 kg (SD 4.2) for men and 45% of women and 60% of men had low ALM. BIA (Kyle) in women (AUC 0.81, 95% confidence interval 0.72-0.89) and BIA (Sergi) in men (AUC 0.89, 95% CI 0.80-0.98) were best able to discriminate between low and normal ALM. Anthropometry (Heymsfield) was less accurate than BIA in women (AUC 0.64, 95% CI 0.54-0.75), and equal to BIA in men (AUC 0.72, 95% CI 0.72 0.56-0.87). BIA (Sergi, Kyle and Tengvall) and anthropometry (Heymsfield) can identify low muscle mass in hip fracture patients.

  14. The role of muscle mass and body fat on disability among older adults: A cross-national analysis.

    PubMed

    Tyrovolas, Stefanos; Koyanagi, Ai; Olaya, Beatriz; Ayuso-Mateos, Jose Luis; Miret, Marta; Chatterji, Somnath; Tobiasz-Adamczyk, Beata; Koskinen, Seppo; Leonardi, Matilde; Haro, Josep Maria

    2015-09-01

    The aim of this study was to evaluate the association of sarcopenia and sarcopenic obesity with disability among older adults (≥65years old) in nine high-, middle- and low-income countries from Asia, Africa, Europe, and Latin America. Data were available for 53,289 people aged ≥18years who participated in the Collaborative Research on Ageing in Europe (COURAGE) survey conducted in Finland, Poland, and Spain, and the WHO Study on global AGEing and adult health (SAGE) survey conducted in China, Ghana, India, Mexico, Russia, and South Africa, between 2007 and 2012. Skeletal muscle mass, skeletal muscle mass index, and percent body fat were calculated with specific population formulas. Sarcopenia and sarcopenic obesity were defined by specific cut-offs used in previous studies. Disability was assessed with the WHODAS 2.0 score (range 0-100) with higher scores corresponding to higher levels of disability. Multivariable linear regression analysis was conducted with disability as the outcome. The analytical sample consisted of 18,363 people (males; n=8116, females; n=10247) aged ≥65years with mean (SD) age 72.9 (11.1) years. In the fully-adjusted overall analysis, sarcopenic obesity was associated with greater levels of disability [b-coefficient 3.01 (95% CI 1.14-4.88)]. In terms of country-wise analyses, sarcopenia was associated with higher WHODAS 2.0 scores in China [b-coefficient 4.56 (95% CI: 3.25-5.87)], Poland [b-coefficient 6.66 (95% CI: 2.17-11.14)], Russia [b-coefficient 5.60 (95% CI: 2.03-9.16)], and South Africa [b-coefficient 7.75 (95% CI: 1.56-13.94)]. Prevention of muscle mass decline may contribute to reducing the global burden of disability. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Skeletal muscle weakness in osteogenesis imperfecta mice.

    PubMed

    Gentry, Bettina A; Ferreira, J Andries; McCambridge, Amanda J; Brown, Marybeth; Phillips, Charlotte L

    2010-09-01

    Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (P(o), P(o)/mg and P(o)/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased P(o) and an inability to sustain P(o) for the 300-ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Teaching Absolute Value Meaningfully

    ERIC Educational Resources Information Center

    Wade, Angela

    2012-01-01

    What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…

  17. Molecular pathways leading to loss of skeletal muscle mass in cancer cachexia--can findings from animal models be translated to humans?

    PubMed

    Mueller, Tara C; Bachmann, Jeannine; Prokopchuk, Olga; Friess, Helmut; Martignoni, Marc E

    2016-02-08

    Cachexia is a multi-factorial, systemic syndrome that especially affects patients with cancer of the gastrointestinal tract, and leads to reduced treatment response, survival and quality of life. The most important clinical feature of cachexia is the excessive wasting of skeletal muscle mass. Currently, an effective treatment is still lacking and the search for therapeutic targets continues. Even though a substantial number of animal studies have contributed to a better understanding of the underlying mechanisms of the loss of skeletal muscle mass, subsequent clinical trials of potential new drugs have not yet yielded any effective treatment for cancer cachexia. Therefore, we questioned to which degree findings from animal studies can be translated to humans in clinical practice and research. A substantial amount of animal studies on the molecular mechanisms of muscle wasting in cancer cachexia has been conducted in recent years. This extensive review of the literature showed that most of their observations could not be consistently reproduced in studies on human skeletal muscle samples. However, studies on human material are scarce and limited in patient numbers and homogeneity. Therefore, their results have to be interpreted critically. More research is needed on human tissue samples to clarify the signaling pathways that lead to skeletal muscle loss, and to confirm pre-selected drug targets from animal models in clinical trials. In addition, improved diagnostic tools and standardized clinical criteria for cancer cachexia are needed to conduct standardized, randomized controlled trials of potential drug candidates in the future.

  18. Muscle Stem Cells: A Model System for Adult Stem Cell Biology.

    PubMed

    Cornelison, Ddw; Perdiguero, Eusebio

    2017-01-01

    Skeletal muscle stem cells, originally termed satellite cells for their position adjacent to differentiated muscle fibers, are absolutely required for the process of skeletal muscle repair and regeneration. In the last decade, satellite cells have become one of the most studied adult stem cell systems and have emerged as a standard model not only in the field of stem cell-driven tissue regeneration but also in stem cell dysfunction and aging. Here, we provide background in the field and discuss recent advances in our understanding of muscle stem cell function and dysfunction, particularly in the case of aging, and the potential involvement of muscle stem cells in genetic diseases such as the muscular dystrophies.

  19. Skeletal muscle mass and body fat in relation to successful ageing of older adults: The multi-national MEDIS study.

    PubMed

    Tyrovolas, Stefanos; Haro, Josep-Maria; Mariolis, Anargiros; Piscopo, Suzanne; Valacchi, Giuseppe; Bountziouka, Vassiliki; Anastasiou, Foteini; Zeimbekis, Akis; Tyrovola, Dimitra; Foscolou, Alexandra; Gotsis, Efthimios; Metallinos, George; Tur, Josep-Antoni; Matalas, Antonia; Lionis, Christos; Polychronopoulos, Evangelos; Panagiotakos, Demosthenes

    2016-01-01

    The determinants that promote successful ageing still remain unknown. The aim of the present work was to evaluate the role of skeletal muscle mass and body fat percentage (BF%), in the level of successful ageing. during 2005-2011, 2663 older (aged 65-100 years) from 21 Mediterranean islands and the rural Mani region (Peloponnesus) of Greece were voluntarily enrolled in the study. Appendicular skeletal muscle mass (ASM), skeletal muscle mass index (SMI) and BF% were calculated using population formulas. Dietary habits, energy intake, expenditure and energy balance were derived throughout standard procedures. A successful ageing index ranging from 0 to 10 was used. The mean ASM mass was 24±6.0kg, the SMI was 0.84±0.21 and the BF% was 44%. Females had lower SMI and higher BF% in comparison with males, respectively [(SMI: 0.66±0.09 vs. 1.03±0.11; BF%: 51% vs. 34%, (p<0.001)]. High successful agers had better rates in ASM (p=0.01), SMI (p<0.001) and BF% (p<0.001), compared with the medium and low successful ones. Changes in SMI [b-coefficient (95% CI):2.14 (1.57 to 2.71)] were positively associated with successful ageing, while changes in BF% [b-coefficient (95% CI): -0.04 (-0.05 to -0.03)] were inversely associated with successful ageing. Results from sensitivity analysis showed that the effects of variations on body composition were consistent, less pronounced in the positive energy balance group and more pronounced among the oldest old. Body composition changes seem to be associated with lower quality of life in the older adults, as measured through successful ageing. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Local applications of myostatin-siRNA with atelocollagen increase skeletal muscle mass and recovery of muscle function.

    PubMed

    Kawakami, Emi; Kawai, Nobuhiko; Kinouchi, Nao; Mori, Hiroyo; Ohsawa, Yutaka; Ishimaru, Naozumi; Sunada, Yoshihide; Noji, Sumihare; Tanaka, Eiji

    2013-01-01

    Growing evidence suggests that small-interfering RNA (siRNA) can promote gene silencing in mammalian cells without induction of interferon synthesis or nonspecific gene suppression. Recently, a number of highly specific siRNAs targeted against disease-causing or disease-promoting genes have been developed. In this study, we evaluate the effectiveness of atelocollagen (ATCOL)-mediated application of siRNA targeting myostatin (Mst), a negative regulator of skeletal muscle growth, into skeletal muscles of muscular dystrophy model mice. We injected a nanoparticle complex containing myostatin-siRNA and ATCOL (Mst-siRNA/ATCOL) into the masseter muscles of mutant caveolin-3 transgenic (mCAV-3Tg) mice, an animal model for muscular dystrophy. Scrambled (scr) -siRNA/ATCOL complex was injected into the contralateral muscles as a control. Two weeks after injection, the masseter muscles were dissected for histometric analyses. To investigate changes in masseter muscle activity by local administration of Mst-siRNA/ATCOL complex, mouse masseter electromyography (EMG) was measured throughout the experimental period via telemetry. After local application of the Mst-siRNA/ATCOL complex, masseter muscles were enlarged, while no significant change was observed on the contralateral side. Histological analysis showed that myofibrils of masseter muscles treated with the Mst-siRNA/ATCOL complex were significantly larger than those of the control side. Real-time PCR analysis revealed a significant downregulation of Mst expression in the treated masseters of mCAV-3Tg mice. In addition, expression of myogenic transcription factors was upregulated in the Mst-siRNA-treated masseter muscle, while expression of adipogenic transcription factors was significantly downregulated. EMG results indicate that masseter muscle activity in mCAV-3Tg mice was increased by local administration of the Mst-siRNA/ATCOL complex. These data suggest local administration of Mst-siRNA/ATCOL complex could lead to

  1. Human Muscle Fiber

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The stimulus of gravity affects RNA production, which helps maintain the strength of human muscles on Earth (top), as seen in this section of muscle fiber taken from an astronaut before spaceflight. Astronauts in orbit and patients on Earth fighting muscle-wasting diseases need countermeasures to prevent muscle atrophy, indicated here with white lipid droplets (bottom) in the muscle sample taken from the same astronaut after spaceflight. Kerneth Baldwin of the University of California, Irvine, is conducting research on how reducing the stimulus of gravity affects production of the RNA that the body uses as a blueprint for making muscle proteins. Muscle proteins are what give muscles their strength, so when the RNA blueprints aren't available for producing new proteins to replace old ones -- a situation that occurs in microgravity -- the muscles atrophy. When the skeletal muscle system is exposed to microgravity during spaceflight, the muscles undergo a reduced mass that translates to a reduction in strength. When this happens, muscle endurance decreases and the muscles are more prone to injury, so individuals could have problems in performing extravehicular activity [space walks] or emergency egress because their bodies are functionally compromised.

  2. Clinical Outcomes of Living Liver Transplantation According to the Presence of Sarcopenia as Defined by Skeletal Muscle Mass, Hand Grip, and Gait Speed.

    PubMed

    Harimoto, N; Yoshizumi, T; Izumi, T; Motomura, T; Harada, N; Itoh, S; Ikegami, T; Uchiyama, H; Soejima, Y; Nishie, A; Kamishima, T; Kusaba, R; Shirabe, K; Maehara, Y

    2017-11-01

    Sarcopenia is an independent predictor of death after living-donor liver transplantation (LDLT). However, the ability of the Asian Working Group for Sarcopenia criteria for sarcopenia (defined as reduced skeletal muscle mass plus low muscle strength) to predict surgical outcomes in patients who have undergone LDLT has not been determined. This study prospectively enrolled 366 patients who underwent LDLT at Kyushu University Hospital. Skeletal muscle area (determined by computed tomography), hand-grip strength, and gait speed were measured in 102 patients before LDLT. We investigated the relationship between sarcopenia and surgical outcomes after LDLT performed in three time periods. The number of patients with lower skeletal muscle area has increased to 52.9% in recent years. The incidence of sarcopenia according to the Asian Working Group for Sarcopenia criteria was 23.5% (24/102). Patients with sarcopenia (defined by skeletal muscle area and functional parameters) had significantly lower skeletal muscle area and weaker hand-grip strength than did those without sarcopenia. Compared with non-sarcopenic patients, patients with sarcopenia also had significantly worse liver function, greater estimated blood loss, greater incidence of postoperative complications of Clavien-Dindo grade IV or greater (including amount of ascites on postoperative day 14, total bilirubin on postoperative day 14, and postoperative sepsis), and longer postoperative hospital stay. Multiple logistic regression analysis revealed sarcopenia as a significant predictor of 6-month mortality. The combination of skeletal muscle mass and function can predict surgical outcomes in LDLT patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Masticatory muscles of mouse do not undergo atrophy in space.

    PubMed

    Philippou, Anastassios; Minozzo, Fabio C; Spinazzola, Janelle M; Smith, Lucas R; Lei, Hanqin; Rassier, Dilson E; Barton, Elisabeth R

    2015-07-01

    Muscle loading is important for maintaining muscle mass; when load is removed, atrophy is inevitable. However, in clinical situations such as critical care myopathy, masticatory muscles do not lose mass. Thus, their properties may be harnessed to preserve mass. We compared masticatory and appendicular muscles responses to microgravity, using mice aboard the space shuttle Space Transportation System-135. Age- and sex-matched controls remained on the ground. After 13 days of space flight, 1 masseter (MA) and tibialis anterior (TA) were frozen rapidly for biochemical and functional measurements, and the contralateral MA was processed for morphologic measurements. Flight TA muscles exhibited 20 ± 3% decreased muscle mass, 2-fold decreased phosphorylated (P)-Akt, and 4- to 12-fold increased atrogene expression. In contrast, MAs had no significant change in mass but a 3-fold increase in P-focal adhesion kinase, 1.5-fold increase in P-Akt, and 50-90% lower atrogene expression compared with limb muscles, which were unaltered in microgravity. Myofibril force measurements revealed that microgravity caused a 3-fold decrease in specific force and maximal shortening velocity in TA muscles. It is surprising that myofibril-specific force from both control and flight MAs were similar to flight TA muscles, yet power was compromised by 40% following flight. Continued loading in microgravity prevents atrophy, but masticatory muscles have a different set point that mimics disuse atrophy in the appendicular muscle. © FASEB.

  4. Immobilization/remobilization and the regulation of muscle mass

    NASA Technical Reports Server (NTRS)

    Almon, R. R.

    1983-01-01

    The relationship between animal body weight and the wet and dry weights of the soleus and EDL muscles was derived. Procedures were examined for tissue homogenization, fractionation, protein determination and DNA determination. A sequence of procedures and buffers were developed to carry out all analyses on one small muscle. This would yield a considerable increase in analytical strength associated with paired statistics. The proposed casting procedure which was to be used for immobilization was reexamined.

  5. Lack of independent effect of type 2 diabetes beyond characteristic comorbidities and medications on small muscle mass exercising muscle blood flow and exercise tolerance.

    PubMed

    Poitras, Veronica J; Bentley, Robert F; Hopkins-Rosseel, Diana H; LaHaye, Stephen A; Tschakovsky, Michael E

    2015-08-01

    Persons with type 2 diabetes (T2D) are believed to have reduced exercise tolerance; this may be partly due to impaired exercising muscle blood flow (MBF). Whether there is an impact of T2D on exercising MBF within the typical constellation of comorbidities (hypertension, dyslipidemia, obesity) and their associated medications has not been investigated. We tested the hypothesis that small muscle mass exercise tolerance is reduced in persons with T2D versus Controls (matched for age, body mass index, fitness, comorbidities, non-T2D medications) and that this is related to blunted MBF. Eight persons with T2D and eight controls completed a forearm critical force (fCFimpulse) test as a measure of exercise tolerance (10-min intermittent maximal effort forearm contractions; the average contraction impulse in the last 30 sec quantified fCFimpulse). Forearm blood flow (FBF; ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured; forearm vascular conductance (FVK) was calculated. Data are means ± SD, T2D versus Control. fCFimpulse was not different between groups (136.9 ± 47.3  N·sec vs. 163.1 ± 49.7 N·sec, P = 0.371) nor was the ∆FBF from rest to during exercise at fCFimpulse (502.9 ± 144.6 vs. 709.1 ± 289.2 mL/min, P = 0.092), or its determinants ∆FVK and ∆MAP (both P > 0.05), although there was considerable interindividual variability. ∆FBF was strongly related to fCFimpulse (r = 0.727, P = 0.002), providing support for the relationship between oxygen delivery and exercise tolerance. We conclude that small muscle mass exercising MBF and exercise tolerance are not impaired in representative persons with T2D versus appropriately matched controls. This suggests that peripheral vascular control impairment does not contribute to reduced exercise tolerance in this population. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and

  6. The Influence of Body Mass Index, Sex, & Muscle Activation on Pressure Distribution During Lateral Falls on the Hip.

    PubMed

    Pretty, Steven P; Martel, Daniel R; Laing, Andrew C

    2017-12-01

    Hip fracture incidence rates are influenced by body mass index (BMI) and sex, likely through mechanistic pathways that influence dynamics of the pelvis-femur system during fall-related impacts. The goal of this study was to extend our understanding of these impact dynamics by investigating the effects of BMI, sex, and local muscle activation on pressure distribution over the hip region during lateral impacts. Twenty participants underwent "pelvis-release experiments" (which simulate a lateral fall onto the hip), including muscle-'relaxed' and 'contracted' trials. Males and low-BMI individuals exhibited 44 and 55% greater peak pressure, as well as 66 and 56% lower peripheral hip force, compared to females and high-BMI individuals, respectively. Local muscle activation increased peak force by 10%, contact area by 17%, and peripheral hip force by 11% compared to relaxed trials. In summary, males and low-BMI individuals exhibited more concentrated loading over the greater trochanter. Muscle activation increased peak force, but this force was distributed over a larger area, preventing increased localized loading over the greater trochanter. These findings suggest potential value in incorporating sex, gender, and muscle activation-specific force distributions as inputs into computational tissue-level models, and have implications for the design of personalized protective devices including wearable hip protectors.

  7. Volumetric muscle loss injury repair using in situ fibrin gel cast seeded with muscle-derived stem cells (MDSCs).

    PubMed

    Matthias, Nadine; Hunt, Samuel D; Wu, Jianbo; Lo, Jonathan; Smith Callahan, Laura A; Li, Yong; Huard, Johnny; Darabi, Radbod

    2018-03-01

    Volumetric muscle defect, caused by trauma or combat injuries, is a major health concern leading to severe morbidity. It is characterized by partial or full thickness loss of muscle and its bio-scaffold, resulting in extensive fibrosis and scar formation. Therefore, the ideal therapeutic option is to use stem cells combined with bio-scaffolds to restore muscle. For this purpose, muscle-derived stem cells (MDSCs) are a great candidate due to their unique multi-lineage differentiation potential. In this study, we evaluated the regeneration potential of MDSCs for muscle loss repair using a novel in situ fibrin gel casting. Muscle defect was created by a partial thickness wedge resection in the tibialis anterior (TA) muscles of NSG mice which created an average of 25% mass loss. If untreated, this defect leads to severe muscle fibrosis. Next, MDSCs were delivered using a novel in situ fibrin gel casting method. Our results demonstrated MDSCs are able to engraft and form new myofibers in the defect when casted along with fibrin gel. LacZ labeled MDSCs were able to differentiate efficiently into new myofibers and significantly increase muscle mass. This was also accompanied by significant reduction of fibrotic tissue in the engrafted muscles. Furthermore, transplanted cells also contributed to new vessel formation and satellite cell seeding. These results confirmed the therapeutic potential of MDSCs and feasibility of direct in situ casting of fibrin/MDSC mixture to repair muscle mass defects. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Using polyphenol derivatives to prevent muscle wasting.

    PubMed

    Francaux, Marc; Deldicque, Louise

    2018-05-01

    To highlight recent evidence for the ability of polyphenols and their derivatives to reduce muscle wasting in different pathological states. From January 2016 to August 2017, four articles dealt with the effects of polyphenols on muscle wasting, which were all carried out in mice. The four studies found that polyphenols reduced muscle mass loss associated with cancer cachexia, acute inflammation or sciatic nerve section. One study even showed that muscle mass was totally preserved when rutin was added to the diet of mice undergoing cancer cachexia. The beneficial effects of polyphenols on muscle wasting were mainly due to a reduction in the activation of the nuclear factor-kappa B pathway, a lower oxidative stress level and a better mitochondrial function. In addition, urolithin B was found to have a testosterone-like effect and to favorably regulate muscle protein balance. During the last 20 months, additional data have been collected about the beneficial effects of rutin, curcumin, quercetin, ellagitanins and urolithin B to limit the loss of muscle mass associated with several pathological states. However, currently, scientific evidence lacks for their use as nutraceuticals in human.

  9. Muscle progenitor cells proliferation doesn't sufficiently contribute to maintaining stretched soleus muscle mass during gravitational unloading

    NASA Astrophysics Data System (ADS)

    Tarakina, M. V.; Turtikova, O. V.; Nemirovskaya, T. L.; Kokontcev, A. A.; Shenkman, B. S.

    Skeletal muscle work hypertrophy is usually connected with muscle progenitor satellite cells (SC) activation with subsequent incorporation of their nuclei into myofibers. Passive stretch of unloaded muscle was earlier established to prevent atrophic processes and is accompanied by enhanced protein synthesis. We hypothesized that elimination of SC proliferation capacity by γ-irradiation would partly avert stretched muscle fiber capability to maintain their size under the conditions of gravitational unloading. To assess the role of muscle progenitor (satellite) cells in development of passive stretch preventive effect SC proliferation was suppressed by local exposing to ionized radiation (2500 rad), subsequent hindlimb suspension or hindlimb suspension with concomitant passive stretch were carried out. Reduction of myofiber cross-sectional area and decrease in myonuclei number accompanying unloaded muscle atrophy were completely abolished by passive stretch both in irradiated and sham-treated animals. We conclude that SC did not make essential contribution to passive stretch preventive action under the conditions of simulated weightlessness.

  10. Absolute Sea-level Changes Derived from Integrated Geodetic Datasets (1955-2016) in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Yang, L.; Wang, G.; Liu, H.

    2017-12-01

    Rising sea level has important direct impacts on coastal and island regions such as the Caribbean where the influence of sea-level rise is becoming more apparent. The Caribbean Sea is a semi-enclosed sea adjacent to the landmasses of South and Central America to the south and west, and the Greater Antilles and the Lesser Antilles separate it from the Atlantic Ocean to the north and east. The work focus on studying the relative and absolute sea-level changes by integrating tide gauge, GPS, and satellite altimetry datasets (1955-2016) within the Caribbean Sea. Further, the two main components of absolute sea-level change, ocean mass and steric sea-level changes, are respectively studied using GRACE, temperature, and salinity datasets (1955-2016). According to the analysis conducted, the sea-level change rates have considerable temporal and spatial variations, and estimates may be subject to the techniques used and observation periods. The average absolute sea-level rise rate is 1.8±0.3 mm/year for the period from 1955 to 2015 according to the integrated tide gauge and GPS observations; the average absolute sea-level rise rate is 3.5±0.6 mm/year for the period from 1993 to 2016 according to the satellite altimetry observations. This study shows that the absolute sea-level change budget in the Caribbean Sea is closed in the periods from 1955 to 2016, in which ocean mass change dominates the absolute sea-level rise. The absolute sea-level change budget is also closed in the periods from 2004 to 2016, in which steric sea-level rise dominates the absolute sea-level rise.

  11. Association between involuntary weight loss with low muscle mass and health-related quality of life in community-dwelling older adults: Nationwide surveys (KNHANES 2008-2011).

    PubMed

    Kim, Miji; Kim, Junghoon; Won, Chang Won

    2018-06-01

    To investigate the relationship between involuntary weight loss with low muscle mass and health-related quality of life in a large representative sample of older adults. A nationwide cross-sectional study based on data from the Korea National Health and Nutritional Examination Survey, 2008 to 2011. Study participants included 2249 individuals aged ≥70 years. The participants reported an unintentional weight loss >3 kg in the past year. Appendicular lean mass was measured using dual-energy X-ray absorptiometry and calculated with the appendicular lean mass index. Health-related quality of life was measured using the EuroQol-5 dimension (EQ-5D) instrument. Univariate and multivariate survey logistic regression models were used to calculate odds ratios (OR) with 95% confidence intervals (95% CI) for the lowest quintile of the EQ-5D index. In total, 39.1% of participants were male and 60.9% were female. The weighted mean age was 75.6 years (95% CI; 75.3-75.9). Clinically significant weight loss is typically 5% of one's body weight; average, 2.8 kg (3.1 kg for men; 2.7 kg, women) for our participants. Compared with the normal reference group and after adjusting for potential confounders, the ORs for the lowest quintile of the EQ-5D indices were 1.39 (95% CI, 0.92-2.10), 2.56 (95% CI, 1.56-4.18), and 3.40 (95% CI, 2.05 to 5.63) for the low muscle mass, involuntary weight loss, involuntary weight loss with low muscle mass groups, respectively. Involuntary weight loss combined with low muscle mass was more closely associated with poor quality of life than involuntary weight loss alone in community-dwelling older adults. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. GH/IGF-I Transgene Expression on Muscle Homeostasis

    NASA Technical Reports Server (NTRS)

    Schwartz, Robert J.

    1999-01-01

    We propose to test the hypothesis that the growth hormone/ insulin like growth factor-I axis through autocrine/paracrine mechanisms may provide long term muscle homeostasis under conditions of prolonged weightlessness. As a key alternative to hormone replacement therapy, ectopic production of hGH, growth hormone releasing hormone (GHRH), and IGF-I will be studied for its potential on muscle mass impact in transgenic mice under simulated microgravity. Expression of either hGH or IGF-I would provide a chronic source of a growth-promoting protein whose biosynthesis or secretion is shut down in space. Muscle expression of the IGF-I transgene has demonstrated about a 20% increase in hind limb muscle mass over control nontransgenic litter mates. These recent experiments, also establish the utility of hind-limb suspension in mice as a workable model to study atrophy in weight bearing muscles. Thus, transgenic mice will be used in hind-limb suspension models to determine the role of GH/IGF-I on maintenance of muscle mass and whether concentric exercises might act in synergy with hormone treatment. As a means to engineer and ensure long-term protein production that would be workable in humans, gene therapy technology will be used by to monitor muscle mass preservation during hind-limb suspension, after direct intramuscular injection of a genetically engineered muscle-specific vector expressing GHRH. Effects of this gene-based therapy will be assessed in both fast twitch (medial gastrocnemius) and slow twitch muscle (soleus). End-points include muscle size, ultrastructure, fiber type, and contractile function, in normal animals, hind limb suspension, and reambutation.

  13. Mortality predictability of body size and muscle mass surrogates in Asian vs white and African American hemodialysis patients.

    PubMed

    Park, Jongha; Jin, Dong Chan; Molnar, Miklos Z; Dukkipati, Ramanath; Kim, Yong-Lim; Jing, Jennie; Levin, Nathan W; Nissenson, Allen R; Lee, Jong Soo; Kalantar-Zadeh, Kamyar

    2013-05-01

    To determine whether the association of body size and muscle mass with survival among patients undergoing long-term hemodialysis (HD) is consistent across race, especially in East Asian vs white and African American patients. Using data from 20,818 patients from South Korea who underwent HD from February 1, 2001, to June 30, 2009, and 20,000 matched patients from the United States (10,000 whites and 10,000 African Americans) who underwent HD from July 1, 2001, to June 30, 2006, we compared mortality associations of baseline body mass index (BMI) and serum creatinine level as likely surrogates of obesity and muscle mass across the 3 races. In Korean HD patients, higher BMI together with higher serum creatinine levels were associated with greater survival, as previously reported from US and European studies. In the matched cohort (10,000 patients from each of the 3 races), mortality risks were lower across higher BMI and serum creatinine levels, and these associations were similar in all 3 races (reference groups: patients with BMI >25.0 kg/m(2) or serum creatinine >12 mg/dL in each race). White, African American, and Korean patients with BMI levels of 18.5 kg/m(2) or less (underweight) had 78%, 79%, and 57% higher mortality risk, respectively, and white, African American, and Korean patients with serum creatinine levels of 6.0 mg/dL or less had 108%, 87%, and 78% higher mortality, respectively. This study shows that race does not modify the association of higher body size and muscle mass with greater survival in HD patients. Given the consistency of the obesity paradox, which may be related to a mitigated effect of protein-energy wasting on mortality irrespective of racial disparities, nutritional support to improve survival should be tested in HD patients of all races. Copyright © 2013 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  14. "Nutraceuticals" in relation to human skeletal muscle and exercise.

    PubMed

    Deane, Colleen S; Wilkinson, Daniel J; Phillips, Bethan E; Smith, Kenneth; Etheridge, Timothy; Atherton, Philip J

    2017-04-01

    Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and "nutraceutical" compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1 ) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2 ) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine. Copyright © 2017 the American Physiological Society.

  15. Jaw-muscle fiber architecture in tufted capuchins favors generating relatively large muscle forces without compromising jaw gape.

    PubMed

    Taylor, Andrea B; Vinyard, Christopher J

    2009-12-01

    Tufted capuchins (sensu lato) are renowned for their dietary flexibility and capacity to exploit hard and tough objects. Cebus apella differs from other capuchins in displaying a suite of craniodental features that have been functionally and adaptively linked to their feeding behavior, particularly the generation and dissipation of relatively large jaw forces. We compared fiber architecture of the masseter and temporalis muscles between C. apella (n=12) and two "untufted" capuchins (C. capucinus, n=3; C. albifrons, n=5). These three species share broadly similar diets, but tufted capuchins occasionally exploit mechanically challenging tissues. We tested the hypothesis that tufted capuchins exhibit architectural properties of their jaw muscles that facilitate relatively large forces including relatively greater physiologic cross-sectional areas (PCSA), more pinnate fibers, and lower ratios of mass to tetanic tension (Mass/P(0)). Results show some evidence supporting these predictions, as C. apella has relatively greater superficial masseter and temporalis PCSAs, significantly so only for the temporalis following Bonferroni adjustment. Capuchins did not differ in pinnation angle or Mass/P(0). As an architectural trade-off between maximizing muscle force and muscle excursion/contraction velocity, we also tested the hypothesis that C. apella exhibits relatively shorter muscle fibers. Contrary to our prediction, there are no significant differences in relative fiber lengths between tufted and untufted capuchins. Therefore, we attribute the relatively greater PCSAs in tufted capuchins primarily to their larger muscle masses. These findings suggest that relatively large jaw-muscle PCSAs can be added to the suite of masticatory features that have been functionally linked to the exploitation of a more resistant diet by C. apella. By enlarging jaw-muscle mass to increase PCSA, rather than reducing fiber lengths and increasing pinnation, tufted capuchins appear to have

  16. Regional changes in muscle mass following 17 weeks of bed rest

    NASA Technical Reports Server (NTRS)

    Leblanc, Adrian D.; Schneider, Victor S.; Evans, Harlan J.; Pientok, Colette; Rowe, Roger; Spector, Elisabeth

    1992-01-01

    This work reports on the muscle loss and recovery after 17 wk of continuous bed rest and 8 wk of reambulation in eight normal male volunteers. Muscle changes were assessed by urinary levels of 3-methylhistidine (3-MeH), nitrogen balance, dual-photon absorptiometry (DPA), magnetic resonance imaging (MRI), and isokinetic muscle performance. The total body lean tissue loss during bed rest calculated from nitrogen balance was 3.9 +/- 2.1 kg. Although the total loss is minimal, DPA scans showed that nearly all of the lean tissue loss occurred in the lower limbs. Similarly, MRI muscle volume measurements showed greater percent loss in the limbs relative to the back muscles. MRI, DPA, and nitrogen balance suggest that muscle atrophy continued throughout bed rest with rapid recovery after reambulaton. Isokinetic muscle strength decreased significantly in the thigh and calf with no loss in the arms and with rapid recovery during reambulation.

  17. Mega-MUSCLES Treasury Survey: Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems

    NASA Astrophysics Data System (ADS)

    Froning, Cynthia

    2017-09-01

    To interpret observations of exoplanets' atmospheres, we must understand the high-energy SEDs of their host stars. We propose to expand our Cycle 19/22 MUSCLES project to: (a) new M dwarf exoplanet hosts with varying properties; (b) reference M dwarfs below 0.3 solar masses that may be used as proxies for M dwarf planet hosts discovered after HST's lifetime; and (c) more rapidly rotating stars of GJ1132's mass to probe XUV evolution over gigayear timescales. We propose to gather the first panchromatic SEDs of rocky planet hosts GJ1132 and Trappist-1. This proposal extends proven methods to a key new sample of stars, upon which critically depends the long-term goal of studying habitable planet atmospheres with JWST and beyond.

  18. Effects of load mass carried in a backpack upon respiratory muscle fatigue.

    PubMed

    Faghy, Mark; Blacker, Sam; Brown, Peter I

    2016-11-01

    The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20 kg, causes respiratory muscle fatigue. Eight males performed four randomised load carriage (LC) trials comprising 60 min walking at 6.5 km h(-1) wearing a backpack of either 0 (LC0), 10 (LC10), 15 (LC15) or 20 kg (LC20). Inspiratory (PImax) and expiratory (PEmax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60 s of each trial. Group mean PImax and PEmax were unchanged following 60-min load carriage in all conditions (p > .05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p < .05) with changes not different between trials (p > .05). These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20 kg in a backpack for up to 60 min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.

  19. The importance of body mass normalisation for ultrasound measurement of the transversus abdominis muscle: The effect of age, gender and sport practice.

    PubMed

    Linek, Pawel

    2017-04-01

    Some studies have not considered body mass as a confounder in TrA analysis, which may have led to improper interpretation of results. To assess the differences in the effect of age, gender and physical activity between normalised for body mass and actual values of the TrA as well as to establish the effect of age, gender and physical activity on normalised for body mass TrA thickness in adolescents. The study was a cross-sectional study conducted at selected primary and secondary schools, and colleges in the Silesian region of Poland. A real-time ultrasound was used to obtain images of the TrA muscle. Body mass normalisation for TrA thickness was performed with allometric scaling and the following equation: Allometric-scaled TrA = TrA thickness/body mass 0.61 . Analysis has shown that boys have significantly thicker muscle by 0.27 mm (95% CI 0.04-0.50) than girls, and those who practise sports have thicker muscle by 0.30 mm (95% CI 0.06-0.52) than non-active individuals. For allometric-scaled TrA, there were no significant effects (p > 0.50). There was a significant correlation between participants age and the actual value of the TrA (r = 0.42, p < 0.05). The correlation between age and allometric-scaled TrA was insignificant and close to zero (r = -0.006, p = 0.93). An analysis of TrA thickness without body mass normalisation can deliver improper interpretation of study results. Thus, it is recommended in future researches to analyse TrA thickness measurement after normalisation rather than actual values. In the adolescent population, there is no effect of gender, age and physical activity on allometric-scaled TrA thickness. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound.

  1. Prophylactic effects of swimming exercise on autophagy-induced muscle atrophy in diabetic rats

    PubMed Central

    Lee, Youngjeon; Kim, Joo-Heon; Hong, Yunkyung; Lee, Sang-Rae; Chang, Kyu-Tae

    2012-01-01

    Diabetes decreases skeletal muscle mass and induces atrophy. However, the mechanisms by which hyperglycemia and insulin deficiency modify muscle mass are not well defined. In this study, we evaluated the effects of swimming exercise on muscle mass and intracellular protein degradation in diabetic rats, and proposed that autophagy inhibition induced by swimming exercise serves as a hypercatabolic mechanism in the skeletal muscles of diabetic rats, supporting a notion that swimming exercise could efficiently reverse the reduced skeletal muscle mass caused by diabetes. Adult male Sprague-Dawley rats were injected intraperitoneally with streptozotocin (60 mg/kg body weight) to induce diabetes and then submitted to 1 hr per day of forced swimming exercise, 5 days per week for 4 weeks. We conducted an intraperitoneal glucose tolerance test on the animals and measured body weight, skeletal muscle mass, and protein degradation and examined the level of autophagy in the isolated extensor digitorum longus, plantaris, and soleus muscles. Body weight and muscle tissue mass were higher in the exercising diabetic rats than in control diabetic rats that remained sedentary. Compared to control rats, exercising diabetic rats had lower blood glucose levels, increased intracellular contractile protein expression, and decreased autophagic protein expression. We conclude that swimming exercise improves muscle mass in diabetes-induced skeletal muscle atrophy, suggesting the activation of autophagy in diabetes contributes to muscle atrophy through hypercatabolic metabolism and that aerobic exercise, by suppressing autophagy, may modify or reverse skeletal muscle wasting in diabetic patients. PMID:23091517

  2. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  3. Ratio of C-Reactive Protein to Albumin Predicts Muscle Mass in Adult Patients Undergoing Hemodialysis

    PubMed Central

    Chen, Yu-Tong; Wu, Pei-Yu; Chen, Hsi-Hsien; Chen, Tso-Hsiao; Hsu, Yung-Ho

    2016-01-01

    Recent studies have indicated that the ratio of C-reactive protein to albumin (CRP–Alb ratio) is associated with clinical outcomes in patients with disease. We examined the predictive value of this ratio in patients undergoing hemodialysis (HD). In this cross-sectional study, 91 eligible adult HD patients were analyzed, and the correlation between the CRP–Alb ratio and skeletal muscle mass normalized for body weight (SMM/wt; estimated using a bioelectrical impedance analyzer) was investigated. The mean age of the study participants was 54.9 ± 6.6 years (ranging from 27 to 64 years); 43 (47.2%) were men. The mean values for the SMM/wt were 39.1% ± 5.4%. The CRP–Alb ratio was found to be negatively correlated with SMM/wt (r = −0.33, P = 0.002) and creatinine (r = −0.20, P = 0.056). All the univariate significant and nonsignificant relevant covariates were selected for multivariable stepwise regression analysis. We determined that the homeostasis model assessment-estimated insulin resistance and CRP–Alb ratio were independent risk determinants for SMM/wt (βHOMA-IR = −0.18 and βCRP–Alb ratio = −3.84, adjusted R2 = 0.32). This study indicated that the CRP–Alb ratio may help clinicians in predicting muscle mass in adult patients undergoing HD. PMID:27768746

  4. Randomized control trial to evaluate the effects of acute testosterone administration in men on muscle mass, strength, and physical function following ACL reconstructive surgery: rationale, design, methods.

    PubMed

    Wu, Brian W; Berger, Max; Sum, Jonathan C; Hatch, George F; Schroeder, E Todd

    2014-12-06

    The anterior cruciate ligament (ACL) is one of four major ligaments in the knee that provide stability during physical activity. A tear in the ACL is characterized by joint instability that leads to decreased activity, knee dysfunction, reduced quality of life and a loss of muscle mass and strength. While rehabilitation is the standard-of-care for return to daily function, additional surgical reconstruction can provide individuals with an opportunity to return to sports and strenuous physical activity. Over 200,000 ACL reconstructions are performed in the United States each year, and rehabilitation following surgery is slow and expensive. One possible method to improve the recovery process is the use of intramuscular testosterone, which has been shown to increase muscle mass and strength independent of exercise. With short-term use of supraphysiologic doses of testosterone, we hope to reduce loss of muscle mass and strength and minimize loss of physical function following ACL reconstruction compared to standard-of-care alone. This study is a double-blinded randomized control trial. Men 18-50 years of age, scheduled for ACL reconstruction are randomized into two groups. Participants randomized to the testosterone group receive intramuscular testosterone administration once per week for 8 weeks starting 2 weeks prior to surgery. Participants randomized to the control group receive a saline placebo intramuscularly instead of testosterone. Lean mass, muscle strength and physical function are measured at 5 time points: 2 weeks pre-surgery, 1 day pre-surgery, and 6, 12, 24 weeks post-surgery. Both groups follow standard-of-care rehabilitation protocol. We believe that testosterone therapy will help reduce the loss of muscle mass and strength experienced after ACL injury and reconstruction. Hopefully this will provide a way to shorten the rehabilitation necessary following ACL reconstruction. If successful, testosterone therapy may also be used for other injuries

  5. Masticatory muscles of mouse do not undergo atrophy in space

    PubMed Central

    Philippou, Anastassios; Minozzo, Fabio C.; Spinazzola, Janelle M.; Smith, Lucas R.; Lei, Hanqin; Rassier, Dilson E.; Barton, Elisabeth R.

    2015-01-01

    Muscle loading is important for maintaining muscle mass; when load is removed, atrophy is inevitable. However, in clinical situations such as critical care myopathy, masticatory muscles do not lose mass. Thus, their properties may be harnessed to preserve mass. We compared masticatory and appendicular muscles responses to microgravity, using mice aboard the space shuttle Space Transportation System-135. Age- and sex-matched controls remained on the ground. After 13 days of space flight, 1 masseter (MA) and tibialis anterior (TA) were frozen rapidly for biochemical and functional measurements, and the contralateral MA was processed for morphologic measurements. Flight TA muscles exhibited 20 ± 3% decreased muscle mass, 2-fold decreased phosphorylated (P)-Akt, and 4- to 12-fold increased atrogene expression. In contrast, MAs had no significant change in mass but a 3-fold increase in P-focal adhesion kinase, 1.5-fold increase in P-Akt, and 50–90% lower atrogene expression compared with limb muscles, which were unaltered in microgravity. Myofibril force measurements revealed that microgravity caused a 3-fold decrease in specific force and maximal shortening velocity in TA muscles. It is surprising that myofibril-specific force from both control and flight MAs were similar to flight TA muscles, yet power was compromised by 40% following flight. Continued loading in microgravity prevents atrophy, but masticatory muscles have a different set point that mimics disuse atrophy in the appendicular muscle.—Philippou, A., Minozzo, F. C., Spinazzola, J. M., Smith, L. R., Lei, H., Rassier, D. E., Barton, E. R. Masticatory muscles of mouse do not undergo atrophy in space. PMID:25795455

  6. Interdependence of physical inactivity, loss of muscle mass and low dietary intake: Extrapulmonary manifestations in older chronic obstructive pulmonary disease patients.

    PubMed

    Yoshimura, Kazuya; Sato, Susumu; Muro, Shigeo; Yamada, Minoru; Hasegawa, Koichi; Kiyokawa, Hirofumi; Mishima, Michiaki; Aoyama, Tomoki

    2018-01-01

    Extrapulmonary manifestations, such as reductions in skeletal muscle and physical inactivity, are important clinical features of patients with chronic obstructive pulmonary disease (COPD), and might depend on the severity of COPD. As it is still unclear whether the relationship between muscle loss and physical inactivity is dominated by a disease-specific relationship or caused by patient factors, including physiological aging, we aimed to investigate the pulmonary or extrapulmonary factors associated with physical inactivity among older COPD patients. A total of 38 older male COPD patients (aged ≥65 years) were enrolled, and were evaluated cross-sectionally. Skeletal muscle mass was measured using bioelectrical impedance, and physical activity and energy intake were recorded for 2 weeks using a pedometer and diary. Daily step counts were successfully evaluated in 28 participants (mean forced expiratory volume in 1 s [%predicted; %FEV 1 ]; 49.5%), and ranged widely. The mean step counts was 5166 steps/day, and found to have a significant relationship with dyspnea (r = -0.46), diffusing capacity (r = 0.47), %FEV1 (r = 0.44), skeletal muscle index (r = 0.59) and total dietary intake (r = 0.47), but not with age (P = 0.14). A stepwise multivariate analysis showed that the skeletal muscle index (β = 0.50) and total dietary intake (β = 0.35) were significant determinants of the daily step count (R 2 = 0.46, p < 0.01). Although various pulmonary factors are associated with daily physical activity, skeletal muscle mass and dietary intake are more closely correlated with physical activity in COPD patients. Because physical inactivity might be the strongest predictor of prognosis, the present results suggest that a comprehensive treatment strategy must be considered for older COPD patients to improve their extrapulmonary manifestations and pulmonary dysfunction. Geriatr Gerontol Int 2018; 18: 88-94. © 2017 Japan Geriatrics Society.

  7. Brain and muscle Arnt-like 1 promotes skeletal muscle regeneration through satellite cell expansion

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

    Chatterjee, Somik; Yin, Hongshan; Department of Cardiovascular Medicine, Third Affiliated Hospital, Hebei Medical University, Shijiazhuang 050051, Hebei

    Circadian clock is an evolutionarily conserved timing mechanism governing diverse biological processes and the skeletal muscle possesses intrinsic functional clocks. Interestingly, although the essential clock transcription activator, Brain and muscle Arnt-like 1 (Bmal1), participates in maintenance of muscle mass, little is known regarding its role in muscle growth and repair. In this report, we investigate the in vivo function of Bmal1 in skeletal muscle regeneration using two muscle injury models. Bmal1 is highly up-regulated by cardiotoxin injury, and its genetic ablation significantly impairs regeneration with markedly suppressed new myofiber formation and attenuated myogenic induction. A similarly defective regenerative response ismore » observed in Bmal1-null mice as compared to wild-type controls upon freeze injury. Lack of satellite cell expansion accounts for the regeneration defect, as Bmal1{sup −/−} mice display significantly lower satellite cell number with nearly abolished induction of the satellite cell marker, Pax7. Furthermore, satellite cell-derived primary myoblasts devoid of Bmal1 display reduced growth and proliferation ex vivo. Collectively, our results demonstrate, for the first time, that Bmal1 is an integral component of the pro-myogenic response that is required for muscle repair. This mechanism may underlie its role in preserving adult muscle mass and could be targeted therapeutically to prevent muscle-wasting diseases. - Highlights: • Bmal1 is highly inducible by muscle injury and myogenic stimuli. • Genetic ablation of Bmal1 significantly impairs muscle regeneration. • Bmal1 promotes satellite cell expansion during muscle regeneration. • Bmal1-deficient primary myoblasts display attenuated growth and proliferation.« less

  8. Expression of a calpastatin transgene slows muscle wasting and obviates changes in myosin isoform expression during murine muscle disuse

    NASA Technical Reports Server (NTRS)

    Tidball, James G.; Spencer, Melissa J.

    2002-01-01

    Muscle wasting is a prominent feature of several systemic diseases, neurological damage and muscle disuse. The contribution of calpain proteases to muscle wasting in any instance of muscle injury or disease has remained unknown because of the inability to specifically perturb calpain activity in vivo. We have generated a transgenic mouse with muscle-specific overexpression of calpastatin, which is the endogenous inhibitor of calpains, and induced muscle atrophy by unloading hindlimb musculature for 10 days. Expression of the transgene resulted in increases in calpastatin concentration in muscle by 30- to 50-fold, and eliminated all calpain activity that was detectable on zymograms. Muscle fibres in ambulatory, transgenic mice were smaller in diameter, but more numerous, so that muscle mass did not differ between transgenic and non-transgenic mice. This is consistent with the role of the calpain-calpastatin system in muscle cell fusion that has been observed in vitro. Overexpression of calpastatin reduced muscle atrophy by 30 % during the 10 day unloading period. In addition, calpastatin overexpression completely prevented the shift in myofibrillar myosin content from slow to fast isoforms, which normally occurs in muscle unloading. These findings indicate that therapeutics directed toward regulating the calpain-calpastatin system may be beneficial in preventing muscle mass loss in muscle injury and disease.

  9. Expression of a calpastatin transgene slows muscle wasting and obviates changes in myosin isoform expression during murine muscle disuse

    PubMed Central

    Tidball, James G; Spencer, Melissa J

    2002-01-01

    Muscle wasting is a prominent feature of several systemic diseases, neurological damage and muscle disuse. The contribution of calpain proteases to muscle wasting in any instance of muscle injury or disease has remained unknown because of the inability to specifically perturb calpain activity in vivo. We have generated a transgenic mouse with muscle-specific overexpression of calpastatin, which is the endogenous inhibitor of calpains, and induced muscle atrophy by unloading hindlimb musculature for 10 days. Expression of the transgene resulted in increases in calpastatin concentration in muscle by 30- to 50-fold, and eliminated all calpain activity that was detectable on zymograms. Muscle fibres in ambulatory, transgenic mice were smaller in diameter, but more numerous, so that muscle mass did not differ between transgenic and non-transgenic mice. This is consistent with the role of the calpain-calpastatin system in muscle cell fusion that has been observed in vitro. Overexpression of calpastatin reduced muscle atrophy by 30 % during the 10 day unloading period. In addition, calpastatin overexpression completely prevented the shift in myofibrillar myosin content from slow to fast isoforms, which normally occurs in muscle unloading. These findings indicate that therapeutics directed toward regulating the calpain-calpastatin system may be beneficial in preventing muscle mass loss in muscle injury and disease. PMID:12482888

  10. Expression of a calpastatin transgene slows muscle wasting and obviates changes in myosin isoform expression during murine muscle disuse.

    PubMed

    Tidball, James G; Spencer, Melissa J

    2002-12-15

    Muscle wasting is a prominent feature of several systemic diseases, neurological damage and muscle disuse. The contribution of calpain proteases to muscle wasting in any instance of muscle injury or disease has remained unknown because of the inability to specifically perturb calpain activity in vivo. We have generated a transgenic mouse with muscle-specific overexpression of calpastatin, which is the endogenous inhibitor of calpains, and induced muscle atrophy by unloading hindlimb musculature for 10 days. Expression of the transgene resulted in increases in calpastatin concentration in muscle by 30- to 50-fold, and eliminated all calpain activity that was detectable on zymograms. Muscle fibres in ambulatory, transgenic mice were smaller in diameter, but more numerous, so that muscle mass did not differ between transgenic and non-transgenic mice. This is consistent with the role of the calpain-calpastatin system in muscle cell fusion that has been observed in vitro. Overexpression of calpastatin reduced muscle atrophy by 30 % during the 10 day unloading period. In addition, calpastatin overexpression completely prevented the shift in myofibrillar myosin content from slow to fast isoforms, which normally occurs in muscle unloading. These findings indicate that therapeutics directed toward regulating the calpain-calpastatin system may be beneficial in preventing muscle mass loss in muscle injury and disease.

  11. Assessment of muscle endurance of the knee extensor muscles in adolescents with spastic cerebral palsy using a submaximal repetitions-to-fatigue protocol.

    PubMed

    Eken, Maaike M; Dallmeijer, Annet J; Doorenbosch, Caroline A; Dekkers, Hurnet; Becher, Jules G; Houdijk, Han

    2014-10-01

    To compare muscle endurance in adolescents with spastic cerebral palsy (CP) with typically developing (TD) peers using a submaximal repetitions-to-fatigue (RTF) protocol. Cross sectional. Human motion laboratory. Adolescents with spastic CP (n=16; Gross Motor Function Classification System levels I or II) and TD adolescents (n=18) within the age range of 12 to 19 years old. Not applicable. Each participant performed 3 RTF tests at different submaximal loads, ranging from 50% to 90% of their maximal voluntary knee extension torque. The relation between the number of repetitions (repetition maximum [RM]) and imposed submaximal relative (percent of maximal voluntary torque [%MVT]) and absolute (Nm/kg) torque was quantified. To compare adolescents with CP with TD adolescents, a mixed linear model was used to construct load endurance curves. Surface electromyography of quadriceps muscles was measured to assess changes in normalized amplitude and median frequency (MF) as physiological indicators of muscle fatigue. Adolescents with CP showed a larger decrease in %MVT per RM than TD adolescents (P<.05). TD adolescents showed substantial higher absolute (Nm/kg) load endurance curves than adolescents with CP (P<.001), but they did not show a difference in slope. Electromyographic normalized amplitude increased significantly (P<.05) in the quadriceps muscles in all tests for both groups. Electromyographic MF decreased significantly (P<.05) in tests with the low and medium loads. Electromyographic responses did not differ between groups, indicating that similar levels of muscle fatigue were reached. Adolescents with CP show slightly lower muscle endurance compared with TD adolescents on a submaximal RTF protocol, which is in contrast with earlier findings in a maximal voluntary fatigue protocol. Accordingly, adolescents with CP have a reduced capacity to endure activities at similar relative loads compared with TD adolescents. Copyright © 2014 American Congress of

  12. Absolutely relative or relatively absolute: violations of value invariance in human decision making.

    PubMed

    Teodorescu, Andrei R; Moran, Rani; Usher, Marius

    2016-02-01

    Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

  13. Statin myalgia is not associated with reduced muscle strength, mass or protein turnover in older male volunteers, but is allied with a slowing of time to peak power output, insulin resistance and differential muscle mRNA expression

    PubMed Central

    Mallinson, Joanne E.; Marimuthu, Kanagaraj; Murton, Andrew; Selby, Anna; Smith, Kenneth; Constantin‐Teodosiu, Dumitru; Rennie, Michael J.

    2015-01-01

    Key points Statins cause muscle‐specific side effects, most commonly muscle aches/weakness (myalgia), particularly in older people. Furthermore, evidence has linked statin use to increased risk of type 2 diabetes. However, the mechanisms involved are unknown.This is the first study to measure muscle protein turnover rates and insulin sensitivity in statin myalgic volunteers and age‐matched, non‐statin users under controlled fasting and fed conditions using gold standard methods.We demonstrate in older people that chronic statin myalgia is not associated with deficits in muscle strength and lean mass or the dysregulation of muscle protein turnover compared to non‐statin users. Furthermore, there were no between‐group differences in blood or muscle inflammatory markers.Statin users did, however, show blunting of muscle power output at the onset of dynamic exercise, increased abdominal adiposity, whole body and leg insulin resistance, and clear differential expression of muscle genes linked to mitochondrial dysfunction and apoptosis, which warrant further investigation. Abstract Statins are associated with muscle myalgia and myopathy, which probably reduce habitual physical activity. This is particularly relevant to older people who are less active, sarcopaenic and at increased risk of statin myalgia. We hypothesised that statin myalgia would be allied to impaired strength and work capacity in older people, and determined whether differences aligned with divergences in lean mass, protein turnover, insulin sensitivity and the molecular regulation of these processes. Knee extensor strength and work output during 30 maximal isokinetic contractions were assessed in healthy male volunteers, nine with no statin use (control 70.4 ± 0.7 years) and nine with statin myalgia (71.5 ± 0.9 years). Whole body and leg glucose disposal, muscle myofibrillar protein synthesis (MPS) and leg protein breakdown (LPB) were measured during fasting (≈5 mU l−1 insulin

  14. Bone and Skeletal Muscle: Key Players in Mechanotransduction and Potential Overlapping Mechanisms

    PubMed Central

    Goodman, Craig A.; Hornberger, Troy A.; Robling, Alexander G.

    2015-01-01

    The development and maintenance of skeletal muscle and bone mass is critical for movement, health and issues associated with the quality of life. Skeletal muscle and bone mass are regulated by a variety of factors that include changes in mechanical loading. Moreover, bone mass is, in large part, regulated by muscle-derived mechanical forces and thus by changes in muscle mass/strength. A thorough understanding of the cellular mechanism(s) responsible for mechanotransduction in bone and skeletal muscle is essential for the development of effective exercise and pharmaceutical strategies aimed at increasing, and/or preventing the loss of, mass in these tissues. Thus, in this review we will attempt to summarize the current evidence for the major molecular mechanisms involved in mechanotransduction in skeletal muscle and bone. By examining the differences and similarities in mechanotransduction between these two tissues, it is hoped that this review will stimulate new insights and ideas for future research and promote collaboration between bone and muscle biologists. PMID:26453495

  15. Per meal dose and frequency of protein consumption is associated with lean mass and muscle performance.

    PubMed

    Loenneke, Jeremy P; Loprinzi, Paul D; Murphy, Caoileann H; Phillips, Stuart M

    2016-12-01

    It has been hypothesized that for older adults evenly distributing consumption of protein at 30-40 g per meal throughout the day may result in more favorable retention of lean mass and muscular strength. Such a thesis has not, to our knowledge, been tested outside of short-term studies or acute measures of muscle protein synthesis. To examine whether the number of times an individual consumed a minimum of 30 g of protein at a meal is associated with leg lean mass and knee extensor strength. Data from the 1999-2002 NHANES were used, with 1081 adults (50-85 y) constituting the analytic sample. A "multiple pass" 24-h dietary interview format was used to collect detailed information about the participants' dietary intake. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. Leg lean mass was estimated from whole-body dual-energy X-ray absorptiometry (DXA) scans. Participants with 1 vs. 0 (β adjusted  = 23.6, p = 0.002) and 2 vs. 0 (β adjusted  = 51.1, p = 0.001) meals of ≥30 g protein/meal had greater strength and leg lean mass (1 vs. 0, β adjusted  = 1160, p < 0.05 and 2 vs. 0, β adjusted  = 2389, p < 0.05). The association of protein frequency with leg lean mass and strength plateaued at ∼45 g protein/meal for those consuming 2 vs. 0 meals above the evaluated protein/meal threshold. However, for those with only 1 meal at or above the evaluated threshold, the response plateaued at 30 g/meal. Leg lean mass mediated the relationship between protein frequency and strength, with the proportion of the total effect mediated being 64%. We found that more frequent consumption of meals containing between 30 and 45 g protein/meal produced the greatest association with leg lean mass and strength. Thus, the consumption of 1-2 daily meals with protein content from 30 to 45 g may be an important strategy for increasing and/or maintaining lean body mass and muscle strength with aging. Copyright © 2016 Elsevier Ltd and

  16. Different Levels of Eccentric Resistance during Eight Weeks of Training Affect Muscle Strength and Lean Tissue Mass

    NASA Technical Reports Server (NTRS)

    English, K. L.; Loehr, J. A.; Lee, S. M. C.; Laughlin, M. S.; Hagan, R. D.

    2008-01-01

    Coupling concentric and eccentric muscle contractions appears to be important in the development of muscle strength and hypertrophy. The interim Resistive Exercise Device (iRED) currently used aboard the International Space Station does not seem to be as effective as free weight training in ambulatory subjects and has not completely protected against muscular deconditioning due to space flight. The lack of protection during space flight could be caused by iRED's proportionally lower eccentric resistance (60-70%) compared to concentric resistance. PURPOSE: To determine the effects of 8 wks of lower body resistive exercise training using five levels of eccentric resistance on muscle strength and lean tissue mass. METHODS: Forty untrained males (34.9 +/- 7 yrs, 80.9 +/- 9.8 kg, 178.2 +/- 7.1 cm; mean +/- SD) completed three 1-repetition maximum (1-RM) strength tests for both the supine leg press (LP) and supine heel raise (HR) prior to training; subjects were matched for LP strength and randomly assigned to one of five training groups. Concentric load (% 1-RM) was constant across groups during training, but each group trained with different levels of eccentric load (0%, 33%, 66%, 100%, or 138% of concentric). Subjects trained 3 d / wk for 8 wks using a periodized program for LP and HR based on percentages of the highest pre-training 1-RM. LP and HR 1-RM and leg lean mass (LLM; assessed by DEXA) were measured pre- and post-training. A two-way ANOVA was used to analyze all dependent measures. Tukey's post hoc tests were used to test significant main effects. Within group pre- to post-training changes were compared using paired t-tests with a Bonferroni adjustment. Statistical significance was set a priori at p 0.05. All data are expressed as mean +/- SE. RESULTS: LP 1-RM strength increased significantly in all groups pre- to post-training. The 138% group increase (20.1 +/- 3.7%) was significantly greater than the 0% (7.9 +/- 2.8%), 33% (7.7 +/- 4.6%), and 66% (7.5 +/- 4

  17. Baicalin supplementation reduces serum biomarkers of skeletal muscle wasting and may protect against lean body mass reduction in cancer patients: Results from a pilot open-label study.

    PubMed

    Emanuele, Enzo; Bertona, Marco; Pareja-Galeano, Helios; Fiuza-Luces, Carmen; Morales, Javier Salvador; Sanchis-Gomar, Fabian; Lucia, Alejandro

    2016-07-01

    Muscle wasting in patients with cancer has been linked to an increased activity of nuclear factor κB (NF-κB) and higher circulating levels of activin-A (ActA), a negative growth factor for muscle mass. Baicalin is a natural flavonoid that can reduce skeletal muscle atrophy in animal models of cancer cachexia by inhibiting NF-κB. This pilot open-label study assessed the effects of baicalin supplementation (50 mg daily for 3 months) in cancer patients who showed involuntary weight loss >5% over the past 6 months. A total of 20 patients were investigated. Participants were evaluated at baseline and at the end of the 3-month study period for the following endpoints: 1) changes from baseline in serum NF-κB and ActA levels; and 2) change from baseline in lean body mass (LBM). We observed significant reduction in both NF-κB (p<0.05) and ActA (p<0.05) serum levels from baseline to 3 months. At 3 months, patients also showed a significant mean increase in LBM (+0.8 kg, p<0.05 compared with baseline). Our pilot open-label data suggest that baicalin supplementation is potentially useful for contrasting lean body mass reduction in cancer patients with involuntary weight loss, an effect which is likely mediated by the inhibition of negative growth factors for muscle mass.

  18. Lean muscle volume of the thigh has a stronger relationship with muscle power than muscle strength in women with knee osteoarthritis.

    PubMed

    Davison, Michael J; Maly, Monica R; Keir, Peter J; Hapuhennedige, Sandani M; Kron, Amie T; Adachi, Jonathan D; Beattie, Karen A

    2017-01-01

    Thigh lean muscle and intramuscular fat have been implicated in the impairment of physical function observed in people with knee osteoarthritis. We investigated the relationships of quadriceps and hamstrings intramuscular fat fraction and lean muscle volume with muscle power and strength, controlling for neuromuscular activation, and physical performance in women with knee OA. Women (n=20) 55years or older with symptomatic, radiographic knee osteoarthritis underwent a 3.0T magnetic resonance imaging scan of the thigh of their most symptomatic knee. Axial fat-separated images were analyzed using software to quantify intramuscular fat and lean muscle volumes of the quadriceps and hamstrings. To quantify strength and power of the knee extensors and flexors, participants performed maximum voluntary isometric contraction and isotonic knee extensions and flexions, respectively. Electromyography of the quadriceps and hamstrings was measured. Participants also completed five physical performance tests. Quadriceps and hamstrings lean muscle volumes were related to isotonic knee extensor (B=0.624; p=0.017) and flexor (B=1.518; p=0.032) power, but not knee extensor (B=0.001; p=0.615) or flexor (B=0.001; p=0.564) isometric strength. Intramuscular fat fractions were not related to isotonic knee extensor or flexor power, nor isometric strength. No relationships were found between intramuscular fat or lean muscle volume and physical performance. Muscle power may be more sensitive than strength to lean muscle mass in women with knee osteoarthritis. Thigh lean muscle mass, but neither intramuscular nor intermuscular fat, is related to knee extensor and flexor power in women with knee osteoarthritis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Mechanical Signal Transduction in Countermeasures to Muscle Atrophy

    NASA Technical Reports Server (NTRS)

    Tidball, James G.; Chu, Amy (Technical Monitor)

    2002-01-01

    We have shown that modifications in muscle use result in changes in the expression and activity of calpains and nitric oxide synthase (NOS). Although muscle unloading for 10 days produced no change in the concentrations of calpain 1 or 2 and no change in calpain activation, muscle reloading produced a 90% increase in calpain 2 concentration. We developed an in vitro model to test our hypothesis that nitric oxide can inhibit cytoskeletal breakdown in skeletal muscle cells by inhibiting calpain cleavage of talin. Talin was selected because it is a well-characterized calpain substrate and it is codistributed with calpain in muscle cells. We found that intermittant loading during hindlimb suspension that is sufficient to prevent muscle mass loss that occurs during muscle unloading is also sufficient to prevent the decrease in NOS expression that normally occurs during hindlimb unloading. These findings indicate that therapeutics directed toward regulating the calpain/calpastatin system may be beneficial in preventing muscle mass loss in muscle injury, unloading and disease.

  20. Simulated space radiation sensitizes bone but not muscle to the catabolic effects of mechanical unloading.

    PubMed

    Krause, Andrew R; Speacht, Toni L; Zhang, Yue; Lang, Charles H; Donahue, Henry J

    2017-01-01

    Deep space travel exposes astronauts to extended periods of space radiation and mechanical unloading, both of which may induce significant muscle and bone loss. Astronauts are exposed to space radiation from solar particle events (SPE) and background radiation referred to as galactic cosmic radiation (GCR). To explore interactions between skeletal muscle and bone under these conditions, we hypothesized that decreased mechanical load, as in the microgravity of space, would lead to increased susceptibility to space radiation-induced bone and muscle loss. We evaluated changes in bone and muscle of mice exposed to hind limb suspension (HLS) unloading alone or in addition to proton and high (H) atomic number (Z) and energy (E) (HZE) (16O) radiation. Adult male C57Bl/6J mice were randomly assigned to six groups: No radiation ± HLS, 50 cGy proton radiation ± HLS, and 50 cGy proton radiation + 10 cGy 16O radiation ± HLS. Radiation alone did not induce bone or muscle loss, whereas HLS alone resulted in both bone and muscle loss. Absolute trabecular and cortical bone volume fraction (BV/TV) was decreased 24% and 6% in HLS-no radiation vs the normally loaded no-radiation group. Trabecular thickness and mineral density also decreased with HLS. For some outcomes, such as BV/TV, trabecular number and tissue mineral density, additional bone loss was observed in the HLS+proton+HZE radiation group compared to HLS alone. In contrast, whereas HLS alone decreased muscle mass (19% gastrocnemius, 35% quadriceps), protein synthesis, and increased proteasome activity, radiation did not exacerbate these catabolic outcomes. Our results suggest that combining simulated space radiation with HLS results in additional bone loss that may not be experienced by muscle.

  1. Isotope pattern deconvolution for peptide mass spectrometry by non-negative least squares/least absolute deviation template matching

    PubMed Central

    2012-01-01

    Background The robust identification of isotope patterns originating from peptides being analyzed through mass spectrometry (MS) is often significantly hampered by noise artifacts and the interference of overlapping patterns arising e.g. from post-translational modifications. As the classification of the recorded data points into either ‘noise’ or ‘signal’ lies at the very root of essentially every proteomic application, the quality of the automated processing of mass spectra can significantly influence the way the data might be interpreted within a given biological context. Results We propose non-negative least squares/non-negative least absolute deviation regression to fit a raw spectrum by templates imitating isotope patterns. In a carefully designed validation scheme, we show that the method exhibits excellent performance in pattern picking. It is demonstrated that the method is able to disentangle complicated overlaps of patterns. Conclusions We find that regularization is not necessary to prevent overfitting and that thresholding is an effective and user-friendly way to perform feature selection. The proposed method avoids problems inherent in regularization-based approaches, comes with a set of well-interpretable parameters whose default configuration is shown to generalize well without the need for fine-tuning, and is applicable to spectra of different platforms. The R package IPPD implements the method and is available from the Bioconductor platform (http://bioconductor.fhcrc.org/help/bioc-views/devel/bioc/html/IPPD.html). PMID:23137144

  2. One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men

    PubMed Central

    Sculthorpe, Nicholas F.; Herbert, Peter; Grace, Fergal

    2017-01-01

    Abstract Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men. PMID:28178145

  3. Loss of skeletal muscle mass during neoadjuvant treatments correlates with worse prognosis in esophageal cancer: a retrospective cohort study.

    PubMed

    Järvinen, Tommi; Ilonen, Ilkka; Kauppi, Juha; Salo, Jarmo; Räsänen, Jari

    2018-02-12

    Nutritional deficits, cachexia, and sarcopenia are extremely common in esophageal cancer. The aim of this article was to assess the effect of loss of skeletal muscle mass during neoadjuvant treatment on the prognosis of esophageal cancer patients. Esophageal cancer patients (N = 115) undergoing neoadjuvant therapy and surgery between 2010 and 2014 were identified from our surgery database and retrospectively analyzed. Computed tomography imaging of the total cross-sectional muscle tissue measured at the third lumbar level defined the skeletal muscle index, which defined sarcopenia (SMI < 52.4 cm2/m2 for men and < 38.5 cm2/m2 for women). Images were collected before and after neoadjuvant treatments. Sarcopenia in preoperative imaging was prevalent in 92 patients (80%). Median overall survival was 900 days (interquartile range 334-1447) with no difference between sarcopenic (median = 900) and non-sarcopenic (median = 914) groups (p = 0.872). Complication rates did not differ (26.1% vs 32.6%, p = 0.725). A 2.98% decrease in skeletal muscle index during neoadjuvant treatment correlated with poor 2-year survival (log-rank p = 0.04). Loss of skeletal muscle tissue during neoadjuvant treatment correlates with worse overall survival.

  4. “Nutraceuticals” in relation to human skeletal muscle and exercise

    PubMed Central

    Deane, Colleen S.; Wilkinson, Daniel J.; Phillips, Bethan E.; Smith, Kenneth; Etheridge, Timothy

    2017-01-01

    Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and “nutraceutical” compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine. PMID:28143855

  5. One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men: A randomized controlled trial.

    PubMed

    Sculthorpe, Nicholas F; Herbert, Peter; Grace, Fergal

    2017-02-01

    Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men.

  6. Effects of high protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial

    USDA-ARS?s Scientific Manuscript database

    Context: The benefits of high protein diets for sparing lean body mass and sustaining skeletal muscle protein metabolism during short-term weight loss in normal-weight adults are not well described. Objective: Determine the effects of varying levels of dietary protein intake on body compos...

  7. Exercise quantity-dependent muscle hypertrophy in adult zebrafish (Danio rerio).

    PubMed

    Hasumura, Takahiro; Meguro, Shinichi

    2016-07-01

    Exercise is very important for maintaining and increasing skeletal muscle mass, and is particularly important to prevent and care for sarcopenia and muscle disuse atrophy. However, the dose-response relationship between exercise quantity, duration/day, and overall duration and muscle mass is poorly understood. Therefore, we investigated the effect of exercise duration on skeletal muscle to reveal the relationship between exercise quantity and muscle hypertrophy in zebrafish forced to exercise. Adult male zebrafish were exercised 6 h/day for 4 weeks, 6 h/day for 2 weeks, or 3 h/day for 2 weeks. Flow velocity was adjusted to maximum velocity during continual swimming (initial 43 cm/s). High-speed consecutive photographs revealed that zebrafish mainly drove the caudal part. Additionally, X-ray micro computed tomography measurements indicated muscle hypertrophy of the mid-caudal half compared with the mid-cranial half part. The cross-sectional analysis of the mid-caudal half muscle revealed that skeletal muscle (red, white, or total) mass increased with increasing exercise quantity, whereas that of white muscle and total muscle increased only under the maximum exercise load condition of 6 h/day for 4 weeks. Additionally, the muscle fiver size distributions of exercised fish were larger than those from non-exercised fish. We revealed that exercise quantity, duration/day, and overall duration were correlated with skeletal muscle hypertrophy. The forced exercise model enabled us to investigate the relationship between exercise quantity and skeletal muscle mass. These results open up the possibility for further investigations on the effects of exercise on skeletal muscle in adult zebrafish.

  8. Waist circumference values equivalent to body mass index points for predicting absolute cardiovascular disease risks among adults in an Aboriginal community: a prospective cohort study.

    PubMed

    Adegbija, Odewumi; Hoy, Wendy E; Wang, Zhiqiang

    2015-11-13

    There have been suggestions that currently recommended waist circumference (WC) cut-off points for Australians of European origin may not be applicable to Aboriginal people who have different body habitus profiles. We aimed to generate equivalent WC values that correspond to body mass index (BMI) points for identifying absolute cardiovascular disease (CVD) risks. Prospective cohort study. An Aboriginal community in Australia's Northern Territory. From 1992 to 1998, 920 adults without CVD, with age, WC and BMI measurements were followed-up for up to 20 years. Incident CVD, coronary artery disease (CAD) and heart failure (HF) events during the follow-up period ascertained from hospitalisation data. We generated WC values with 10-year absolute risks equivalent for the development of CVD as BMI values (20-34 kg/m(2)) using the Weibull accelerated time-failure model. There were 211 incident cases of CVD over 13,669 person-years of follow-up. At the average age of 35 years, WC values with absolute CVD, CAD and HF risks equivalent to BMI of 25 kg/m(2) were 91.5, 91.8 and 91.7 cm, respectively, for males, and corresponding WC values were 92.5, 92.7 and 93 cm for females. WC values with equal absolute CVD, CAD and HF risks to BMI of 30 kg/m(2) were 101.7, 103.1 and 102.6 cm, respectively, for males, and corresponding values were 99.2, 101.6 and 101.5 cm for females. Association between WC and CVD did not depend on gender (p=0.54). WC ranging from 91 to 93 cm was equivalent to BMI 25 kg/m(2) for overweight, and 99 to 103 cm was equivalent to BMI of 30 kg/m(2) for obesity in terms of predicting 10-year absolute CVD risk. Replicating the absolute risk method in other Aboriginal communities will further validate the WC values generated for future development of WC cut-off points for Aboriginal people. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  9. Acute effects of self-selected regimen of rapid body mass loss in combat sports athletes.

    PubMed

    Timpmann, Saima; Oöpik, Vahur; Pääsuke, Mati; Medijainen, Luule; Ereline, Jaan

    2008-01-01

    The purpose of the study was to assess the acute effects of the self-selected regimen of rapid body mass loss (RBML) on muscle performance and metabolic response to exercise in combat sports athletes. Seventeen male athletes (20.8 ± 1.0 years; mean ± SD) reduced their body mass by 5.1 ± 1.1% within 3 days. The RBML was achieved by a gradual reduction of energy and fluid intake and mild sauna procedures. A battery of tests was performed before (Test 1) and immediately after (Test 2) RBML. The test battery included the measurement of the peak torque of knee extensors for three different speeds, assessment of total work (Wtot) performed during a 3-min intermittent intensity knee extension exercise and measurements of blood metabolites (ammonia, lactate, glucose and urea). Absolute peak torque was lower in Test 2 compared with Test 1 at angular velocities of 1.57 rad·s(-1) (218.6 ± 40.9 vs. 234.4 ± 42.2 N·m; p = 0.013) and 3.14 rad·s(-1) (100.3 ± 27.8 vs. 111.7 ± 26.2 N·m; p = 0.008). The peak torque in relation to body mass remained unchanged for any speed. Absolute Wtot was lower in Test 2 compared with Test 1 (6359 ± 2326 vs. 7452 ± 3080 J; p = 0.003) as well as Wtot in relation to body mass (89.1 ± 29.9 vs. 98.6 ± 36.4 J·kg(-1); p = 0.034), respectively. As a result of RBML, plasma urea concentration increased from 4.9 to 5.9 mmol·l(-1) (p = 0.003). The concentration of ammonia in a post-test sample in Test 2 tended to be higher in comparison with Test 1 (80.9 ± 29.1 vs. 67.6 ± 26.5 mmol·l(-1); p = 0.082). The plasma lactate and glucose responses to exercise were similar in Test 1 and Test 2. We conclude that the self-selected regimen of RBML impairs muscle performance in 3-min intermittent intensity exercise and induces an increase in blood urea concentration in experienced male combat sports athletes. Key pointsPrevious studies have revealed a negative effect of rapid body mass loss on performance. However, there are some performance

  10. Skeletal Muscle Regeneration, Repair and Remodelling in Aging: The Importance of Muscle Stem Cells and Vascularization.

    PubMed

    Joanisse, Sophie; Nederveen, Joshua P; Snijders, Tim; McKay, Bryon R; Parise, Gianni

    2017-01-01

    Sarcopenia is the age-related loss of skeletal muscle mass and strength. Ultimately, sarcopenia results in the loss of independence, which imposes a large financial burden on healthcare systems worldwide. A critical facet of sarcopenia is the diminished ability for aged muscle to regenerate, repair and remodel. Over the years, research has focused on elucidating underlying mechanisms of sarcopenia and the impaired ability of muscle to respond to stimuli with aging. Muscle-specific stem cells, termed satellite cells (SC), play an important role in maintaining muscle health throughout the lifespan. It is well established that SC are essential in skeletal muscle regeneration, and it has been hypothesized that a reduction and/or dysregulation of the SC pool, may contribute to accelerated loss of skeletal muscle mass that is observed with advancing age. The preservation of skeletal muscle tissue and its ability to respond to stimuli may be impacted by reduced SC content and impaired function observed with aging. Aging is also associated with a reduction in capillarization of skeletal muscle. We have recently demonstrated that the distance between type II fibre-associated SC and capillaries is greater in older compared to younger adults. The greater distance between SC and capillaries in older adults may contribute to the dysregulation in SC activation ultimately impairing muscle's ability to remodel and, in extreme circumstances, regenerate. This viewpoint will highlight the importance of optimal SC activation in addition to skeletal muscle capillarization to maximize the regenerative potential of skeletal muscle in older adults. © 2016 S. Karger AG, Basel.

  11. Lean muscle mass in classic or ovulatory PCOS: association with central obesity and insulin resistance.

    PubMed

    Mario, F M; do Amarante, F; Toscani, M K; Spritzer, P M

    2012-10-01

    This age-matched case-control study assessed total and segmental lean muscle mass in classic or ovulatory polycystic ovary syndrome (PCOS) patients and investigated whether lean mass is associated with hormone and metabolic features. Participants underwent anthropometric and clinical evaluation. Habitual physical activity was assessed with a digital pedometer, and body composition by dual-energy X-ray absorptiometry. Laboratory measurements included total cholesterol, cholesterol fractions, triglycerides, glucose, total serum testosterone, serum insulin, estradiol, luteinizing hormone, and SHBG. Energy intake was calculated using a food frequency questionnaire. Classic PCOS patients had higher body mass index (BMI), waist circumference, testosterone and lipid accumulation product values than ovulatory PCOS and controls. Energy consumption, homeostasis model assessment index, SHBG, free androgen index and triglycerides, total and trunk lean mass were higher only in classic PCOS women vs. controls. Arm, leg, trunk, total or limb lean masses were not correlated with hormone levels in any of the groups. However, in PCOS women lipid accumulation product was positively correlated with total (r=0.56, p=0.001), trunk (r=0.59, p=0.001), arm (r=0.54, p=0.001), leg (r=0.44, p=0.03) and limb (r=0.48, p=0.001) lean masses. BMI was positively correlated with all lean mass segments and independently associated with total lean mass. Lipid accumulation product and BMI were independently associated with trunk lean mass variation. The increase in lean mass in classic PCOS appears to be associated with insulin resistance and central obesity rather than with energy intake, physical activity or androgens. © J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York.

  12. Endocrine regulation of fetal skeletal muscle growth: impact on future metabolic health

    PubMed Central

    Brown, Laura D.

    2014-01-01

    Establishing sufficient skeletal muscle mass is essential for lifelong metabolic health. The intrauterine environment is a major determinant of the muscle mass that is present for the life course of an individual, because muscle fiber number is set at the time of birth. Thus, a compromised intrauterine environment from maternal nutrient restriction or placental insufficiency that restricts development of muscle fiber number can have permanent effects on the amount of muscle an individual will live with. Reduced muscle mass due to fewer muscle fibers persists even after compensatory or “catch up” postnatal growth occurs. Furthermore, muscle hypertrophy can only partially compensate for this limitation in fiber number. Compelling associations link low birth weight and decreased muscle mass to future insulin resistance, which can drive the development of the metabolic syndrome and type 2 diabetes, and risk for cardiovascular events later in life. There are gaps in knowledge about the origins of reduced muscle growth at the cellular level and how these patterns are set during fetal development. By understanding the nutrient and endocrine regulation of fetal skeletal muscle growth and development, we can direct research efforts towards improving muscle growth early in life in order to prevent the development of chronic metabolic disease later in life. PMID:24532817

  13. Evaluation of Skeletal Muscle Function in Lung Transplant Candidates.

    PubMed

    Rozenberg, Dmitry; Singer, Lianne G; Herridge, Margaret; Goldstein, Roger; Wickerson, Lisa; Chowdhury, Noori A; Mathur, Sunita

    2017-09-01

    Lung transplantation (LTx) is offered to older and more complex patients who may be at higher risk of skeletal muscle dysfunction, but the clinical implications of this remain uncertain. The study aims were to characterize deficits in skeletal muscle mass, strength and physical performance, and examine the associations of these deficits with clinical outcomes. Fifty LTx candidates (58% men; age, 59 ± 9 years) were prospectively evaluated for skeletal muscle deficits: muscle mass using bioelectrical impedance, quadriceps, respiratory muscle and handgrip strength, and physical performance with the Short Physical Performance Battery. Comparisons between number of muscle deficits (low muscle mass, quadriceps strength and physical performance) and 6-minute walk distance (6MWD), London Chest Activity of Daily Living Questionnaire, and quality of life were assessed using one-way analysis of variance. Associations with pretransplant and posttransplant delisting/mortality, hospital duration, and 3-month posttransplant 6MWD were evaluated using Fisher exact test and Spearman correlation. Deficits in quadriceps strength (n = 27) and physical performance (n = 24) were more common than muscle mass (n = 8). LTx candidates with 2 or 3 muscle deficits (42%) compared with those without any deficits (26%) had worse 6MWD = -109 m (95% confidence interval [CI], -175 to -43), London Chest Activity of Daily Living Questionnaire = 18 (95% CI, 7-30), and St. George's Activity Domain = 12 (95% CI, 2-21). Number of muscle deficits was associated with posttransplant hospital stay (r = 0.34, P = 0.04), but not with delisting/mortality or posttransplant 6MWD. Deficits in quadriceps muscle strength and physical performance are common in LTx candidates and further research is needed to assess whether modifying muscle function pretransplant can lead to improved clinical outcomes.

  14. Against Laplacian Reduction of Newtonian Mass to Spatiotemporal Quantities

    NASA Astrophysics Data System (ADS)

    Martens, Niels C. M.

    2018-05-01

    Laplace wondered about the minimal choice of initial variables and parameters corresponding to a well-posed initial value problem. Discussions of Laplace's problem in the literature have focused on choosing between spatiotemporal variables relative to absolute space (i.e. substantivalism) or merely relative to other material bodies (i.e. relationalism) and between absolute masses (i.e. absolutism) or merely mass ratios (i.e. comparativism). This paper extends these discussions of Laplace's problem, in the context of Newtonian Gravity, by asking whether mass needs to be included in the initial state at all, or whether a purely spatiotemporal initial state suffices. It is argued that mass indeed needs to be included; removing mass from the initial state drastically reduces the predictive and explanatory power of Newtonian Gravity.

  15. Against Laplacian Reduction of Newtonian Mass to Spatiotemporal Quantities

    NASA Astrophysics Data System (ADS)

    Martens, Niels C. M.

    2018-03-01

    Laplace wondered about the minimal choice of initial variables and parameters corresponding to a well-posed initial value problem. Discussions of Laplace's problem in the literature have focused on choosing between spatiotemporal variables relative to absolute space (i.e. substantivalism) or merely relative to other material bodies (i.e. relationalism) and between absolute masses (i.e. absolutism) or merely mass ratios (i.e. comparativism). This paper extends these discussions of Laplace's problem, in the context of Newtonian Gravity, by asking whether mass needs to be included in the initial state at all, or whether a purely spatiotemporal initial state suffices. It is argued that mass indeed needs to be included; removing mass from the initial state drastically reduces the predictive and explanatory power of Newtonian Gravity.

  16. How the Brain May Have Shaped Muscle Anatomy and Physiology: A Preliminary Study.

    PubMed

    Muchlinski, Magdalena N; Hemingway, Holden W; Pastor, Juan; Omstead, Kailey M; Burrows, Anne M

    2018-03-01

    Skeletal muscle fibers are often used to evaluate functional differences in locomotion. However, because there are energetic differences among muscle fiber cells, muscle fiber composition could be used to address evolutionary questions about energetics. Skeletal muscle is composed of two main types of fibers: Type I and II. The difference between the two can be reduced to how these muscle cells use oxygen and glucose. Type I fibers convert glucose to ATP using oxygen, while Type II fibers rely primarily on anaerobic metabolic processes. The expensive tissue hypothesis (ETH) proposes that the energetic demands imposed on the body by the brain result in a reduction in other expensive tissues (e.g., gastrointestinal tract). The original ETH dismisses the energetic demands of skeletal muscle, despite skeletal muscle being (1) an expensive tissue when active and (2) in direct competition for glucose with the brain. Based on these observations we hypothesize that larger brained primates will have relatively less muscle mass and a decrease in Type I fibers. As part of a larger study to test this hypothesis, we present data from 10 species of primates. We collected body mass, muscle mass, and biopsied four muscles from each specimen for histological procedures. We collected endocranial volumes from the literature. Using immunohistochemistry, a muscle fiber composition profile was created for each species sampled. Results show that larger brained primates have less muscle and fewer Type I fibers than primates with smaller brains. Results clarify the relationship between muscle mass and brain mass and illustrate how muscle mass could be used to address energetic questions. Anat Rec, 301:528-537, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  17. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses. © 2013 John Wiley & Sons Ltd.

  18. Regional muscle loss after short duration spaceflight.

    PubMed

    LeBlanc, A; Rowe, R; Schneider, V; Evans, H; Hedrick, T

    1995-12-01

    Muscle strength and limb girth measurements during Skylab and Apollo missions suggested that loss of muscle mass may occur as a result of spaceflight. Extended duration spaceflight is important for the economical and practical use of space. The loss of muscle mass during spaceflight is a medical concern for long duration flights to the planets or extended stays aboard space stations. Understanding the extent and temporal relationships of muscle loss is important for the development of effective spaceflight countermeasures. We hypothesized that significant and measurable changes in muscle volume would occur in Shuttle crewmembers following 8 d of weightlessness. MRI was used to obtain the muscle volumes of the calf, thigh and lower back before and after the STS-47 Shuttle mission. Statistical analyses demonstrated that the soleus-gastrocnemius (-6.3%), anterior calf (-3.9%), hamstrings (-8.3%), quadriceps (-6.0%) and intrinsic back (-10.3%) muscles were decreased, p < 0.05, compared to baseline, 24 h after landing. At 2 weeks post recovery, the hamstrings and intrinsic lower back muscles were still below baseline, p < 0.05. These results demonstrate that even short duration spaceflight can result in significant muscle atrophy.

  19. Combined Increases in Muscle-Strengthening Activity Frequency and Protein Intake Reveal Graded Relationship with Fat-Free Mass Percentage in U.S. Adults, NHANES (1999-2004).

    PubMed

    Kurka, J M; Vezina, J; Brown, D D; Schumacher, J; Cullen, R W; Laurson, K R

    2015-01-01

    Age-related loss of muscle mass and related ailments are of concern due to associations with disabilities and morbidity as well as constituting a substantial healthcare burden. Muscle-strengthening activities and adequate protein ingestion are recommended for all-age adults in an effort to stave off age-related muscle atrophy. Muscle building abilities decline with age but most research focuses on muscle wasting in the elderly. To examine the independent and combined associations of protein intake (g∙kg-1∙day-1) and muscle-strengthening frequency (times∙week-1, MSF) on fat-free mass percentage (FFM%). This cross-sectional analysis of a population-based sample with data from the non-institutionalized persons in the United States participating in the National Health and Nutrition Examination Survey (cycles 1999-2000, 2001-2002, 2003-2004) consisted of male (n=2,499) and female (n=2,373) participants 20-49 years of age for analyses. MSF was determined by self-report and protein intake was calculated from a 24-hour recall. Differences in FFM% from bioelectrical impedance analysis was estimated using multiple linear regression models controlling for education, race-ethnicity, standing height, and total Caloric intake. One unit increase in MSF or protein intake (β-coefficient, ±E) was associated with significantly more FFM% in males (0.6±0.1%; 3.5±0.4%) and females (0.4±0.1%; 5.9±0.4%). Independent of protein intake, males and females with MSF=0 had mean ±SE FFM% of 74.4±0.4 and 60.7±0.3, respectively, while mean ±SE FFM% of males and females who met the recommendation of ≥2 times per week were 77.9±0.5 and 63.0±0.4. Independent of MSF, males and females with protein intakes below the recommended dietary allowance (RDA) of 0.8 g∙kg-1∙day-1 had mean ±SE FFM% of 74.0±0.6 and 58.2±0.6, respectively, while mean ±SE FFM% of those whose intakes exceeded the recommendation were 75.6±0.4 and 62.0±0.4. The subgroup with the highest mean ±SE FFM% (80

  20. Dexamethasone and BCAA Failed to Modulate Muscle Mass and mTOR Signaling in GH-Deficient Rats

    PubMed Central

    Nishida, Hikaru; Ikegami, Ayaka; Kaneko, Chiaki; Kakuma, Hitomi; Nishi, Hisano; Tanaka, Noriko; Aoyama, Michiko; Usami, Makoto; Okimura, Yasuhiko

    2015-01-01

    Branched-chain amino acids (BCAAs) and IGF-I, the secretion of which is stimulated by growth hormone (GH), prevent muscle atrophy. mTOR plays a pivotal role in the protective actions of BCAA and IGF-1. The pathway by which BCAA activates mTOR is different from that of IGF-1, which suggests that BCAA and GH work independently. We tried to examine whether BCAA exerts a protective effect against dexamethasone (Dex)-induced muscle atrophy independently of GH using GH-deficient spontaneous dwarf rats (SDRs). Unexpectedly, Dex did not induce muscle atrophy assessed by the measurement of cross-sectional area (CSA) of the muscle fibers and did not increase atrogin-1, MuRF1 and REDD1 expressions, which are activated during protein degradation. Glucocorticoid (GR) mRNA levels were higher in SDRs compared to GH-treated SDRs, indicating that the low expression of GR is not the reason of the defect of Dex’s action in SDRs. BCAA did not stimulate the phosphorylation of p70S6K or 4E-BP1, which stimulate protein synthesis. BCAA did not decrease the mRNA level of atrogin-1 or MuRF1. These findings suggested that Dex failed to modulate muscle mass and that BCAA was unable to activate mTOR in SDRs because these phosphorylations of p70S6K and 4E-BP1 and the reductions of these mRNAs are regulated by mTOR. In contrast, after GH supplementation, these responses to Dex were normalized and muscle fiber CSA was decreased by Dex. BCAA prevented the Dex-induced decrease in CSA. BCAA increased the phosphorylation of p70S6K and decreased the Dex-induced elevations of atrogin-1 and Bnip3 mRNAs. However, the amount of mTORC1 components including mTOR was not decreased in the SDRs compared to the normal rats. These findings suggest that GH increases mTORC1 activity but not its content to recover the action of BCAA in SDRs and that GH is required for actions of Dex and BCAA in muscles. PMID:26086773

  1. Dexamethasone and BCAA Failed to Modulate Muscle Mass and mTOR Signaling in GH-Deficient Rats.

    PubMed

    Nishida, Hikaru; Ikegami, Ayaka; Kaneko, Chiaki; Kakuma, Hitomi; Nishi, Hisano; Tanaka, Noriko; Aoyama, Michiko; Usami, Makoto; Okimura, Yasuhiko

    2015-01-01

    Branched-chain amino acids (BCAAs) and IGF-I, the secretion of which is stimulated by growth hormone (GH), prevent muscle atrophy. mTOR plays a pivotal role in the protective actions of BCAA and IGF-1. The pathway by which BCAA activates mTOR is different from that of IGF-1, which suggests that BCAA and GH work independently. We tried to examine whether BCAA exerts a protective effect against dexamethasone (Dex)-induced muscle atrophy independently of GH using GH-deficient spontaneous dwarf rats (SDRs). Unexpectedly, Dex did not induce muscle atrophy assessed by the measurement of cross-sectional area (CSA) of the muscle fibers and did not increase atrogin-1, MuRF1 and REDD1 expressions, which are activated during protein degradation. Glucocorticoid (GR) mRNA levels were higher in SDRs compared to GH-treated SDRs, indicating that the low expression of GR is not the reason of the defect of Dex's action in SDRs. BCAA did not stimulate the phosphorylation of p70S6K or 4E-BP1, which stimulate protein synthesis. BCAA did not decrease the mRNA level of atrogin-1 or MuRF1. These findings suggested that Dex failed to modulate muscle mass and that BCAA was unable to activate mTOR in SDRs because these phosphorylations of p70S6K and 4E-BP1 and the reductions of these mRNAs are regulated by mTOR. In contrast, after GH supplementation, these responses to Dex were normalized and muscle fiber CSA was decreased by Dex. BCAA prevented the Dex-induced decrease in CSA. BCAA increased the phosphorylation of p70S6K and decreased the Dex-induced elevations of atrogin-1 and Bnip3 mRNAs. However, the amount of mTORC1 components including mTOR was not decreased in the SDRs compared to the normal rats. These findings suggest that GH increases mTORC1 activity but not its content to recover the action of BCAA in SDRs and that GH is required for actions of Dex and BCAA in muscles.

  2. JunB transcription factor maintains skeletal muscle mass and promotes hypertrophy

    PubMed Central

    Raffaello, Anna; Milan, Giulia; Masiero, Eva; Carnio, Silvia; Lee, Donghoon

    2010-01-01

    The size of skeletal muscle cells is precisely regulated by intracellular signaling networks that determine the balance between overall rates of protein synthesis and degradation. Myofiber growth and protein synthesis are stimulated by the IGF-1/Akt/mammalian target of rapamycin (mTOR) pathway. In this study, we show that the transcription factor JunB is also a major determinant of whether adult muscles grow or atrophy. We found that in atrophying myotubes, JunB is excluded from the nucleus and that decreasing JunB expression by RNA interference in adult muscles causes atrophy. Furthermore, JunB overexpression induces hypertrophy without affecting satellite cell proliferation and stimulated protein synthesis independently of the Akt/mTOR pathway. When JunB is transfected into denervated muscles, fiber atrophy is prevented. JunB blocks FoxO3 binding to atrogin-1 and MuRF-1 promoters and thus reduces protein breakdown. Therefore, JunB is important not only in dividing populations but also in adult muscle, where it is required for the maintenance of muscle size and can induce rapid hypertrophy and block atrophy. PMID:20921137

  3. A high whey protein-, leucine-, and vitamin D-enriched supplement preserves muscle mass during intentional weight loss in obese older adults: a double-blind randomized controlled trial.

    PubMed

    Verreijen, Amely M; Verlaan, Sjors; Engberink, Mariëlle F; Swinkels, Sophie; de Vogel-van den Bosch, Johan; Weijs, Peter J M

    2015-02-01

    Intentional weight loss in obese older adults is a risk factor for muscle loss and sarcopenia. The objective was to examine the effect of a high whey protein-, leucine-, and vitamin D-enriched supplement on muscle mass preservation during intentional weight loss in obese older adults. We included 80 obese older adults in a double-blind randomized controlled trial. During a 13-wk weight loss program, all subjects followed a hypocaloric diet (-600 kcal/d) and performed resistance training 3×/wk. Subjects were randomly allocated to a high whey protein-, leucine-, and vitamin D-enriched supplement including a mix of other macro- and micronutrients (150 kcal, 21 g protein; 10×/wk, intervention group) or an isocaloric control. The primary outcome was change in appendicular muscle mass. The secondary outcomes were body composition, handgrip strength, and physical performance. Data were analyzed by using ANCOVA and mixed linear models with sex and baseline value as covariates. At baseline, mean ± SD age was 63 ± 5.6 y, and body mass index (in kg/m(2)) was 33 ± 4.4. During the trial, protein intake was 1.11 ± 0.28 g · kg body weight(-1) · d(-1) in the intervention group compared with 0.85 ± 0.24 g · kg body weight(-1) · d(-1) in the control group (P < 0.001). Both intervention and control groups decreased in body weight (-3.4 ± 3.6 kg and -2.8 ± 2.8 kg; both P < 0.001) and fat mass (-3.2 ± 3.1 kg and -2.5 ± 2.4 kg; both P < 0.001), with no differences between groups. The 13-wk change in appendicular muscle mass, however, was different in the intervention and control groups [+0.4 ± 1.2 kg and -0.5 ± 2.1 kg, respectively; β = 0.95 kg (95% CI: 0.09, 1.81); P = 0.03]. Muscle strength and function improved over time without significant differences between groups. A high whey protein-, leucine-, and vitamin D-enriched supplement compared with isocaloric control preserves appendicular muscle mass in obese older adults during a hypocaloric diet and resistance

  4. Respiratory Muscle Plasticity

    PubMed Central

    Gransee, Heather M.; Mantilla, Carlos B.; Sieck, Gary C.

    2014-01-01

    Muscle plasticity is defined as the ability of a given muscle to alter its structural and functional properties in accordance with the environmental conditions imposed on it. As such, respiratory muscle is in a constant state of remodeling, and the basis of muscle’s plasticity is its ability to change protein expression and resultant protein balance in response to varying environmental conditions. Here, we will describe the changes of respiratory muscle imposed by extrinsic changes in mechanical load, activity, and innervation. Although there is a large body of literature on the structural and functional plasticity of respiratory muscles, we are only beginning to understand the molecular-scale protein changes that contribute to protein balance. We will give an overview of key mechanisms regulating protein synthesis and protein degradation, as well as the complex interactions between them. We suggest future application of a systems biology approach that would develop a mathematical model of protein balance and greatly improve treatments in a variety of clinical settings related to maintaining both muscle mass and optimal contractile function of respiratory muscles. PMID:23798306

  5. Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength.

    PubMed

    Douma, K W; Regterschot, G R H; Krijnen, W P; Slager, G E C; van der Schans, C P; Zijlstra, W

    2016-01-01

    The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various degrees of extension. Measurements between 110 and 130° extension present the highest values and the most significant increase after training. The objective of this study is to determine the test-retest reliability of muscle strength measurements by the Q Force in older adults in 110° extension. Forty-one healthy older adults, 13 males and 28 females were included in the study. Mean (SD) age was 81.9 (4.89) years. Isometric muscle strength of the Quadriceps muscle was assessed with the Q Force at 110° of knee extension. Participants were measured at two sessions with a three to eight day interval between sessions. To determine relative reliability, the intraclass correlation coefficient (ICC) was calculated. To determine absolute reliability, Bland and Altman Limits of Agreement (LOA) were calculated and t-tests were performed. Relative reliability of the Q Force is good to excellent as all ICC coefficients are higher than 0.75. Generally a large 95 % LOA, reflecting only moderate absolute reliability, is found as exemplified for the peak torque left leg of -18.6 N to 33.8 N and the right leg of -9.2 N to 26.4 N was between 15.7 and 23.6 Newton representing 25.2 % to 39.9 % of the size of the mean. Small systematic differences in mean were found between measurement session 1 and 2. The present study shows that the Q Force has excellent relative test-retest reliability, but limited absolute test-retest reliability. Since the Q Force is relatively cheap and mobile it is suitable for

  6. Similar muscles contribute to horizontal and vertical acceleration of center of mass in forward and backward walking: implications for neural control

    PubMed Central

    Jansen, Karen; De Groote, Friedl; Massaad, Firas; Meyns, Pieter; Jonkers, Ilse

    2012-01-01

    Leg kinematics during backward walking (BW) are very similar to the time-reversed kinematics during forward walking (FW). This suggests that the underlying muscle activation pattern could originate from a simple time reversal, as well. Experimental electromyography studies have confirmed that this is the case for some muscles. Furthermore, it has been hypothesized that muscles showing a time reversal should also exhibit a reversal in function [from accelerating the body center of mass (COM) to decelerating]. However, this has not yet been verified in simulation studies. In the present study, forward simulations were used to study the effects of muscles on the acceleration of COM in FW and BW. We found that a reversal in function was indeed present in the muscle control of the horizontal movement of COM (e.g., tibialis anterior and gastrocnemius). In contrast, muscles' antigravity contributions maintained their function for both directions of movement. An important outcome of the present study is therefore that similar muscles can be used to achieve opposite functional demands at the level of control of the COM when walking direction is reversed. However, some muscles showed direction-specific contributions (i.e., dorsiflexors). We concluded that the changes in muscle contributions imply that a simple time reversal would be insufficient to produce BW from FW. We therefore propose that BW utilizes extra elements, presumably supraspinal, in addition to a common spinal drive. These additions are needed for propulsion and require a partial reconfiguration of lower level common networks. PMID:22423005

  7. Pharmacological inhibition of myostatin and changes in lean body mass and lower extremity muscle size in patients receiving androgen deprivation therapy for prostate cancer.

    PubMed

    Padhi, Desmond; Higano, Celestia S; Shore, Neal D; Sieber, Paul; Rasmussen, Erik; Smith, Matthew R

    2014-10-01

    Myostatin is a negative regulator of muscle growth. Androgen deprivation (ADT) is associated with muscle loss and increased body fat, and currently available therapies have limited efficacy to treat this complication. The antimyostatin peptibody (AMG 745/Mu-S) markedly attenuated muscle loss and decreased fat accumulation in orchiectomized mice. The objective of the study was to evaluate the safety, pharmacokinetics, and muscle efficacy of AMG 745 in men undergoing ADT for nonmetastatic prostate cancer. This was a randomized, blinded, placebo-controlled, multiple-dose, phase 1 study of AMG 745 given for 28 days. The end point of percentage change from baseline in lean body mass (LBM) as assessed by dual x-ray absorptiometry was prespecified. Rates of adverse events (AMG 745 vs placebo) were the following: diarrhea (13% vs 9%), fatigue (13% vs 4%), contusion (10% vs 0%), and injection site bruising (6% vs 4%). Exposure increased linearly from 0.3 mg/kg to 3 mg/kg. AMG 745 significantly increased LBM in the 3 mg/kg vs the placebo groups on day 29 by 2.2% (±0.8% SE, P = 0.008); in exploratory fat mass analysis, a decrease of -2.5% (±1.0% SE, P = 0.021) was observed. Pharmacodynamic changes in muscle and fat were maintained at follow-up, 1 month after day 29. Four weekly s.c. doses of AMG 745 were well tolerated and were associated with increased LBM and decreased fat in the men receiving ADT for nonmetastatic prostate cancer. RESULTS support further investigation of AMG 745 in clinical settings with muscle loss and atrophy.

  8. Optical Cross-Sectional Muscle Area Determination of Drosophila Melanogaster Adult Indirect Flight Muscles.

    PubMed

    Selma-Soriano, Estela; Artero, Rubén; Llamusi, Beatriz

    2018-03-31

    Muscle mass wasting, known as muscle atrophy, is a common phenotype in Drosophila models of neuromuscular diseases. We have used the indirect flight muscles (IFMs) of flies, specifically the dorso-longitudinal muscles (DLM), as the experimental subject to measure the atrophic phenotype brought about by different genetic causes. In this protocol, we describe how to embed fly thorax muscles for semi thin sectioning, how to obtain a good contrast between muscle and the surrounding tissue, and how to process optical microscope images for semiautomatic acquisition of quantifiable data and analysis. We describe three specific applications of the methodological pipeline. First, we show how the method can be applied to quantify muscle degeneration in a myotonic dystrophy fly model; second, measurement of muscle cross-sectional area can help to identify genes that either promote or prevent muscle atrophy and/or muscle degeneration; third, this protocol can be applied to determine whether a candidate compound is able to significantly modify a given atrophic phenotype induced by a disease-causing mutation or by an environmental trigger.

  9. Comparison of different mass spectrometry techniques in the measurement of L-[ring-13C6]phenylalanine incorporation into mixed muscle proteins

    PubMed Central

    Zabielski, Piotr; Ford, G. Charles; Persson, X. Mai; Jaleel, Abdul; Dewey, Jerry D.; Nair, K Sreekumaran

    2013-01-01

    Precise measurement of low enrichment of stable isotope labeled amino-acid tracers in tissue samples is a prerequisite in measuring tissue protein synthesis rates. The challenge of this analysis is augmented when small sample size is a critical factor. Muscle samples from human participants following an 8 hour intravenous infusion of L-[ring-13C6]phenylalanine and a bolus dose of L-[ring-13C6]phenylalanine in a mouse were utilized. Liquid Chromatography tandem mass spectrometry (LC/MS/MS), Gas Chromatography tandem mass spectrometry (GC/MS/MS) and Gas Chromatography/Mass spectrometry (GC/MS) were compared to the Gas Chromatography-Combustion-Isotope Ratio mass spectrometry (GC/C/IRMS), to measure mixed muscle protein enrichment of [ring13C6]phenylalanine enrichment. The sample isotope enrichment ranged from 0.0091 to 0.1312 Molar Percent excess (MPE). As compared with GC/C/IRMS, LC/MS/MS, GC/MS/MS and GC/MS showed coefficients of determination of R2 = 0.9962 and R2 = 0.9942, and 0.9217 respectively. However, the precision of measurements (coefficients of variation) for intra-assay are 13.0%, 1.7%, 6.3% and 13.5% and for inter-assay are 9.2%, 3.2%, 10.2% and 25% for GC/C/IRMS, LC/MS/MS, GC/MS/MS and GC/MS respectively. The muscle sample sizes required to obtain these results were 8μg, 0.8μg, 3μg and 3μg for GC/C/IRMS, LC/MS/MS, GC/MS/MS, and GC/MS respectively. We conclude that LC/MS/MS is optimally suited for precise measurements of L-[ring-13C6]phenylalanine tracer enrichment in low abundance and in small quantity samples. PMID:23378099

  10. Measured and modelled absolute gravity in Greenland

    NASA Astrophysics Data System (ADS)

    Nielsen, E.; Forsberg, R.; Strykowski, G.

    2012-12-01

    Present day changes in the ice volume in glaciated areas like Greenland will change the load on the Earth and to this change the lithosphere will respond elastically. The Earth also responds to changes in the ice volume over a millennial time scale. This response is due to the viscous properties of the mantle and is known as Glaical Isostatic Adjustment (GIA). Both signals are present in GPS and absolute gravity (AG) measurements and they will give an uncertainty in mass balance estimates calculated from these data types. It is possible to separate the two signals if both gravity and Global Positioning System (GPS) time series are available. DTU Space acquired an A10 absolute gravimeter in 2008. One purpose of this instrument is to establish AG time series in Greenland and the first measurements were conducted in 2009. Since then are 18 different Greenland GPS Network (GNET) stations visited and six of these are visited more then once. The gravity signal consists of three signals; the elastic signal, the viscous signal and the direct attraction from the ice masses. All of these signals can be modelled using various techniques. The viscous signal is modelled by solving the Sea Level Equation with an appropriate ice history and Earth model. The free code SELEN is used for this. The elastic signal is modelled as a convolution of the elastic Greens function for gravity and a model of present day ice mass changes. The direct attraction is the same as the Newtonian attraction and is calculated as this. Here we will present the preliminary results of the AG measurements in Greenland. We will also present modelled estimates of the direct attraction, the elastic and the viscous signals.

  11. Biochemical assessment of the hibernator skeletal muscle properties in search of a potential countermeasure against muscle atrophy in space microgravity

    NASA Astrophysics Data System (ADS)

    Lee, K.; Park, J. Y.; Gwag, T.; Yoo, W.; Choi, I.

    Mammalian skeletal muscle undergoes significant loss of mass and tension capacity during spaceflight or hindlimb suspension This is contrasted by observed features of hibernators in that muscle mass and contractility remain fairly unchanged during a prolonged period of dormancy In an effort of finding potential countermeasure against muscle atrophy in space microgravity we thereby investigated the biochemical properties of the pectoral muscle in a winter-hibernating bat Murina leucogaster Two-dimensional electrophoresis on overall muscle proteins and western blot analysis on heat shock proteins HSP 60 kD 70 kD and 90 kD were conducted to compare levels of myofiber proteins and the stress responsive chaperone molecules in winter-hibernation WH versus summer-active bats SA No seasonal difference was found in the ratio of muscle mass to body mass for the pectoral muscles confirming similar results in previous reports Among more than thirty proteins identified only 14 of the proteins showed significant reduction in the level for WH compared to SA The level of HSP60 and HSP90 in WH were 63 and 71 that in SA respectively P quad 0 05 whereas that of HSP70 was not different between the two groups However when the WH were forced to arouse for 40 min from hibernation the level of HSP70 increased 1 4-fold and 1 51-fold that of WH and SA respectively while the level of HSP90 increased 1 57-fold that of WH These results suggest that the levels of many key contractile and regulatory proteins were retained during

  12. Chronic Stimulation-Induced Changes in the Rodent Thyroarytenoid Muscle

    ERIC Educational Resources Information Center

    McMullen, Colleen A.; Butterfield, Timothy A.; Dietrich, Maria; Andreatta, Richard D.; Andrade, Francisco H.; Fry, Lisa; Stemple, Joseph C.

    2011-01-01

    Purpose: Therapies for certain voice disorders purport principles of skeletal muscle rehabilitation to increase muscle mass, strength, and endurance. However, applicability of limb muscle rehabilitation to the laryngeal muscles has not been tested. In this study, the authors examined the feasibility of the rat thyroarytenoid muscle to remodel as a…

  13. Impact of Virtual Touch Quantification in Acoustic Radiation Force Impulse for Skeletal Muscle Mass Loss in Chronic Liver Diseases

    PubMed Central

    Nishikawa, Hiroki; Nishimura, Takashi; Enomoto, Hirayuki; Iwata, Yoshinori; Ishii, Akio; Miyamoto, Yuho; Ishii, Noriko; Yuri, Yukihisa; Takata, Ryo; Hasegawa, Kunihiro; Nakano, Chikage; Yoh, Kazunori; Aizawa, Nobuhiro; Sakai, Yoshiyuki; Ikeda, Naoto; Takashima, Tomoyuki; Nishiguchi, Shuhei; Iijima, Hiroko

    2017-01-01

    Background and aims: We sought to clarify the relationship between virtual touch quantification (VTQ) in acoustic radiation force impulse and skeletal muscle mass as assessed by bio-electronic impedance analysis in patients with chronic liver diseases (CLDs, n = 468, 222 males and 246 females, median age = 62 years). Patients and methods: Decreased skeletal muscle index (D-SMI) was defined as skeletal muscle index (SMI) <7.0 kg/m2 for males and as SMI <5.7 kg/m2 for females, according to the recommendations in current Japanese guidelines. We examined the correlation between SMI and VTQ levels and investigated factors linked to D-SMI in the univariate and multivariate analyses. The area under the receiver operating curve (AUROC) for the presence of D-SMI was also calculated. Results: In patients with D-SMI, the median VTQ level was 1.64 meters/second (m/s) (range, 0.93–4.32 m/s), while in patients without D-SMI, the median VTQ level was 1.11 m/s (range, 0.67–4.09 m/s) (p < 0.0001). In the multivariate analysis, higher VTQ was found to be an independent predictor linked to the presence of D-SMI (p < 0.0001). In receiver operating characteristic analysis, body mass index had the highest AUROC (0.805), followed by age (0.721) and VTQ (0.706). Conclusion: VTQ levels can be useful for predicting D-SMI in patients with CLDs. PMID:28621757

  14. Effects of whole-body vibration training on physical function, bone and muscle mass in adolescents and young adults with cerebral palsy

    PubMed Central

    Gusso, Silmara; Munns, Craig F; Colle, Patrícia; Derraik, José G B; Biggs, Janene B; Cutfield, Wayne S; Hofman, Paul L

    2016-01-01

    We performed a clinical trial on the effects of whole-body vibration training (WBVT) on muscle function and bone health of adolescents and young adults with cerebral palsy. Forty participants (11.3–20.8 years) with mild to moderate cerebral palsy (GMFCS II–III) underwent 20-week WBVT on a vibration plate for 9 minutes/day 4 times/week at 20 Hz (without controls). Assessments included 6-minute walk test, whole-body DXA, lower leg pQCT scans, and muscle function (force plate). Twenty weeks of WBVT were associated with increased lean mass in the total body (+770 g; p = 0.0003), trunk (+410 g; p = 0.004), and lower limbs (+240 g; p = 0.012). Bone mineral content increased in total body (+48 g; p = 0.0001), lumbar spine (+2.7 g; p = 0.0003), and lower limbs (+13 g; p < 0.0001). Similarly, bone mineral density increased in total body (+0.008 g/cm2; p = 0.013), lumbar spine (+0.014 g/cm2; p = 0.003), and lower limbs (+0.023 g/cm2; p < 0.0001). Participants reduced the time taken to perform the chair test, and improved the distance walked in the 6-minute walk test by 11% and 35% for those with GMFCS II and III, respectively. WBVT was associated with increases in muscle mass and bone mass and density, and improved mobility of adolescents and young adults with cerebral palsy. PMID:26936535

  15. Effects of whole-body vibration training on physical function, bone and muscle mass in adolescents and young adults with cerebral palsy.

    PubMed

    Gusso, Silmara; Munns, Craig F; Colle, Patrícia; Derraik, José G B; Biggs, Janene B; Cutfield, Wayne S; Hofman, Paul L

    2016-03-03

    We performed a clinical trial on the effects of whole-body vibration training (WBVT) on muscle function and bone health of adolescents and young adults with cerebral palsy. Forty participants (11.3-20.8 years) with mild to moderate cerebral palsy (GMFCS II-III) underwent 20-week WBVT on a vibration plate for 9 minutes/day 4 times/week at 20 Hz (without controls). Assessments included 6-minute walk test, whole-body DXA, lower leg pQCT scans, and muscle function (force plate). Twenty weeks of WBVT were associated with increased lean mass in the total body (+770 g; p = 0.0003), trunk (+410 g; p = 0.004), and lower limbs (+240 g; p = 0.012). Bone mineral content increased in total body (+48 g; p = 0.0001), lumbar spine (+2.7 g; p = 0.0003), and lower limbs (+13 g; p < 0.0001). Similarly, bone mineral density increased in total body (+0.008 g/cm(2); p = 0.013), lumbar spine (+0.014 g/cm(2); p = 0.003), and lower limbs (+0.023 g/cm(2); p < 0.0001). Participants reduced the time taken to perform the chair test, and improved the distance walked in the 6-minute walk test by 11% and 35% for those with GMFCS II and III, respectively. WBVT was associated with increases in muscle mass and bone mass and density, and improved mobility of adolescents and young adults with cerebral palsy.

  16. Morphological analysis of the hindlimb in apes and humans. I. Muscle architecture.

    PubMed

    Payne, R C; Crompton, R H; Isler, K; Savage, R; Vereecke, E E; Günther, M M; Thorpe, S K S; D'Août, K

    2006-06-01

    We present quantitative data on the hindlimb musculature of Pan paniscus, Gorilla gorilla gorilla, Gorilla gorilla graueri, Pongo pygmaeus abelii and Hylobates lar and discuss the findings in relation to the locomotor habits of each. Muscle mass and fascicle length data were obtained for all major hindlimb muscles. Physiological cross-sectional area (PCSA) was estimated. Data were normalized assuming geometric similarity to allow for comparison of animals of different size/species. Muscle mass scaled closely to (body mass)(1.0) and fascicle length scaled closely to (body mass)(0.3) in most species. However, human hindlimb muscles were heavy and had short fascicles per unit body mass when compared with non-human apes. Gibbon hindlimb anatomy shared some features with human hindlimbs that were not observed in the non-human great apes: limb circumferences tapered from proximal-to-distal, fascicle lengths were short per unit body mass and tendons were relatively long. Non-human great ape hindlimb muscles were, by contrast, characterized by long fascicles arranged in parallel, with little/no tendon of insertion. Such an arrangement of muscle architecture would be useful for locomotion in a three dimensionally complex arboreal environment.

  17. Morphological analysis of the hindlimb in apes and humans. I. Muscle architecture

    PubMed Central

    Payne, R C; Crompton, R H; Isler, K; Savage, R; Vereecke, E E; Günther, M M; Thorpe, S K S; D'Août, K

    2006-01-01

    We present quantitative data on the hindlimb musculature of Pan paniscus, Gorilla gorilla gorilla, Gorilla gorilla graueri, Pongo pygmaeus abelii and Hylobates lar and discuss the findings in relation to the locomotor habits of each. Muscle mass and fascicle length data were obtained for all major hindlimb muscles. Physiological cross-sectional area (PCSA) was estimated. Data were normalized assuming geometric similarity to allow for comparison of animals of different size/species. Muscle mass scaled closely to (body mass)1.0 and fascicle length scaled closely to (body mass)0.3 in most species. However, human hindlimb muscles were heavy and had short fascicles per unit body mass when compared with non-human apes. Gibbon hindlimb anatomy shared some features with human hindlimbs that were not observed in the non-human great apes: limb circumferences tapered from proximal-to-distal, fascicle lengths were short per unit body mass and tendons were relatively long. Non-human great ape hindlimb muscles were, by contrast, characterized by long fascicles arranged in parallel, with little/no tendon of insertion. Such an arrangement of muscle architecture would be useful for locomotion in a three dimensionally complex arboreal environment. PMID:16761973

  18. Myostatin--the holy grail for muscle, bone, and fat?

    PubMed

    Buehring, B; Binkley, N

    2013-12-01

    Myostatin, a member of the transforming growth factor beta (TGF-β) superfamily, was first described in 1997. Since then, myostatin has gained growing attention because of the discovery that myostatin inhibition leads to muscle mass accrual. Myostatin not only plays a key role in muscle homeostasis, but also affects fat and bone. This review will focus on the impact of myostatin and its inhibition on muscle mass/function, adipose tissue and bone density/geometry in humans. Although existing data are sparse, myostatin inhibition leads to increased lean mass and 1 study found a decrease in fat mass and increase in bone formation. In addition, myostatin levels are increased in sarcopenia, cachexia and bed rest whereas they are increased after resistance training, suggesting physiological regulatory of myostatin. Increased myostatin levels have also been found in obesity and levels decrease after weight loss from caloric restriction. Knowledge on the relationship of myostatin with bone is largely based on animal data where elevated myostatin levels lead to decreased BMD and myostatin inhibition improved BMD. In summary, myostatin appears to be a key factor in the integrated physiology of muscle, fat, and bone. It is unclear whether myostatin directly affects fat and bone, or indirectly via muscle. Whether via direct or indirect effects, myostatin inhibition appears to increase muscle and bone mass and decrease fat tissue-a combination that truly appears to be a holy grail. However, at this time, human data for both efficacy and safety are extremely limited. Moreover, whether increased muscle mass also leads to improved function remains to be determined. Ultimately potential beneficial effects of myostatin inhibition will need to be determined based on hard outcomes such as falls and fractures.

  19. Metallomics investigations on potential binding partners of methylmercury in tuna fish muscle tissue using complementary mass spectrometric techniques.

    PubMed

    Kutscher, Daniel J; Sanz-Medel, Alfredo; Bettmer, Jörg

    2012-08-01

    In this study, the binding behaviour of methylmercury (MeHg(+)) towards proteins is investigated. Free sulfhydryl groups in cysteine residues are known to be the most likely binding partners, due to the high affinity of mercury to sulphur. However, detailed knowledge about discrete binding sites in living organisms has been so far scarce. A metallomics approach using different methods like size-exclusion chromatography (SEC) and liquid chromatography (LC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) as well as complementary mass spectrometric techniques (electrospray ionisation-tandem mass spectrometry, ESI-MS/MS) are combined to sequence and identify possible target proteins or peptides after enzymatic digestion. Potential targets for MeHg(+) in tuna fish muscle tissue are investigated using the certified reference material CRM464 as a model tissue. Different extraction procedures appropriate for the extraction of proteins are evaluated for their efficiency using isotope dilution analysis for the determination of total Hg in the extracts. Due to the high chemical stability of the mercury-sulphur bond, the bioconjugate can be quantitatively extracted with a combination of tris(hydroxymethyl)aminomethane (TRIS) and sodium dodecyl sulphate (SDS). Using different separation techniques such as SEC and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) it can be shown that major binding occurs to a high-molecular weight protein (M(w) > 200 kDa). A potential target protein, skeletal muscle myosin heavy chain, could be identified after tryptic digestion and capillary LC-ESI-MS/MS.

  20. The Human Skeletal Muscle Proteome Project: a reappraisal of the current literature

    PubMed Central

    Gonzalez‐Freire, Marta; Semba, Richard D.; Ubaida‐Mohien, Ceereena; Fabbri, Elisa; Scalzo, Paul; Højlund, Kurt; Dufresne, Craig; Lyashkov, Alexey

    2016-01-01

    Abstract Skeletal muscle is a large organ that accounts for up to half the total mass of the human body. A progressive decline in muscle mass and strength occurs with ageing and in some individuals configures the syndrome of ‘sarcopenia’, a condition that impairs mobility, challenges autonomy, and is a risk factor for mortality. The mechanisms leading to sarcopenia as well as myopathies are still little understood. The Human Skeletal Muscle Proteome Project was initiated with the aim to characterize muscle proteins and how they change with ageing and disease. We conducted an extensive review of the literature and analysed publically available protein databases. A systematic search of peer‐reviewed studies was performed using PubMed. Search terms included ‘human’, ‘skeletal muscle’, ‘proteome’, ‘proteomic(s)’, and ‘mass spectrometry’, ‘liquid chromatography‐mass spectrometry (LC‐MS/MS)’. A catalogue of 5431 non‐redundant muscle proteins identified by mass spectrometry‐based proteomics from 38 peer‐reviewed scientific publications from 2002 to November 2015 was created. We also developed a nosology system for the classification of muscle proteins based on localization and function. Such inventory of proteins should serve as a useful background reference for future research on changes in muscle proteome assessed by quantitative mass spectrometry‐based proteomic approaches that occur with ageing and diseases. This classification and compilation of the human skeletal muscle proteome can be used for the identification and quantification of proteins in skeletal muscle to discover new mechanisms for sarcopenia and specific muscle diseases that can be targeted for the prevention and treatment. PMID:27897395

  1. Absolute gravimetry as an operational tool for geodynamics research

    NASA Astrophysics Data System (ADS)

    Torge, W.

    Relative gravimetric techniques have been used for nearly 30 years for measuring non-tidal gravity variations with time, and thus have contributed to geodynamics research by monitoring vertical crustal movements and internal mass shifts. With today's accuracy of about ± 0.05µms-2 (or 5µGal), significant results have been obtained in numerous control nets of local extension, especially in connection with seismic and volcanic events. Nevertheless, the main drawbacks of relative gravimetry, which are deficiencies in absolute datum and calibration, set a limit for its application, especially with respect to large-scale networks and long-term investigations. These problems can now be successfully attacked by absolute gravimetry, with transportable gravimeters available since about 20 years. While the absolute technique during the first two centuries of gravimetry's history was based on the pendulum method, the free-fall method can now be employed taking advantage of laser-interferometry, electronic timing, vacuum and shock absorbing techniques, and on-line computer-control. The accuracy inherent in advanced instruments is about ± 0.05 µms-2. In field work, generally an accuracy of ±0.1 µms-2 may be expected, strongly depending on local environmental conditions.

  2. The Emerging Role of Skeletal Muscle Metabolism as a Biological Target and Cellular Regulator of Cancer-Induced Muscle Wasting

    PubMed Central

    Carson, James A.; Hardee, Justin P.; VanderVeen, Brandon N.

    2015-01-01

    While skeletal muscle mass is an established primary outcome related to understanding cancer cachexia mechanisms, considerable gaps exist in our understanding of muscle biochemical and functional properties that have recognized roles in systemic health. Skeletal muscle quality is a classification beyond mass, and is aligned with muscle’s metabolic capacity and substrate utilization flexibility. This supplies an additional role for the mitochondria in cancer-induced muscle wasting. While the historical assessment of mitochondria content and function during cancer-induced muscle loss was closely aligned with energy flux and wasting susceptibility, this understanding has expanded to link mitochondria dysfunction to cellular processes regulating myofiber wasting. The primary objective of this article is to highlight muscle mitochondria and oxidative metabolism as a biological target of cancer cachexia and also as a cellular regulator of cancer-induced muscle wasting. Initially, we examine the role of muscle metabolic phenotype and mitochondria content in cancer-induced wasting susceptibility. We then assess the evidence for cancer-induced regulation of skeletal muscle mitochondrial biogenesis, dynamics, mitophagy, and oxidative stress. In addition, we discuss environments associated with cancer cachexia that can impact the regulation of skeletal muscle oxidative metabolism. The article also examines the role of cytokine-mediated regulation of mitochondria function regulation, followed by the potential role of cancer-induced hypogonadism. Lastly, a role for decreased muscle use in cancer-induced mitochondrial dysfunction is reviewed. PMID:26593326

  3. Impact of placental insufficiency on fetal skeletal muscle growth

    PubMed Central

    Hay, William W.

    2016-01-01

    Intrauterine growth restriction (IUGR) caused by placental insufficiency is one of the most common and complex problems in perinatology, with no known cure. In pregnancies affected by placental insufficiency, a poorly functioning placenta restricts nutrient supply to the fetus and prevents normal fetal growth. Among other significant deficits in organ development, the IUGR fetus characteristically has less lean body and skeletal muscle mass than their appropriately-grown counterparts. Reduced skeletal muscle growth is not fully compensated after birth, as individuals who were born small for gestational age (SGA) from IUGR have persistent reductions in muscle mass and strength into adulthood. The consequences of restricted muscle growth and accelerated postnatal “catch-up” growth in the form of adiposity may contribute to the increased later life risk for visceral adiposity, peripheral insulin resistance, diabetes, and cardiovascular disease in individuals who were formerly IUGR. This review will discuss how an insufficient placenta results in impaired fetal skeletal muscle growth and how lifelong reductions in muscle mass might contribute to increased metabolic disease risk in this vulnerable population. PMID:26994511

  4. Muscle atrophy in cachexia: can dietary protein tip the balance?

    PubMed

    Op den Kamp, Céline M; Langen, Ramon C; Haegens, Astrid; Schols, Annemie M

    2009-11-01

    To review the efficacy of dietary protein supplementation in attenuating muscle atrophy in cachexia. Only very few recent randomized controlled trials have studied the effects of protein supplementation in clinical cachexia. It appears that supplementation of dietary protein (>1.5 g/kg per day) alone or in combination with other anabolic stimuli such as exercise training maintains or even improves muscle mass, but results on muscle function are controversial and no clinical studies have yet directly linked alterations in cellular signaling or metabolic signatures of protein intake-induced muscle anabolism to muscle weight gain. To elucidate the role of dietary protein supplementation in attenuating muscle atrophy in cachectic patients, randomized clinical trials are needed in adequately phenotyped patients using sensitive measures of muscle mass and function.

  5. Role of protein and amino acids in promoting lean mass accretion with resistance exercise and attenuating lean mass loss during energy deficit in humans.

    PubMed

    Churchward-Venne, Tyler A; Murphy, Caoileann H; Longland, Thomas M; Phillips, Stuart M

    2013-08-01

    Amino acids are major nutrient regulators of muscle protein turnover. After protein ingestion, hyperaminoacidemia stimulates increased rates of skeletal muscle protein synthesis, suppresses muscle protein breakdown, and promotes net muscle protein accretion for several hours. These acute observations form the basis for strategized protein intake to promote lean mass accretion, or prevent lean mass loss over the long term. However, factors such as protein dose, protein source, and timing of intake are important in mediating the anabolic effects of amino acids on skeletal muscle and must be considered within the context of evaluating the reported efficacy of long-term studies investigating protein supplementation as part of a dietary strategy to promote lean mass accretion and/or prevent lean mass loss. Current research suggests that dietary protein supplementation can augment resistance exercise-mediated gains in skeletal muscle mass and strength and can preserve skeletal muscle mass during periods of diet-induced energy restriction. Perhaps less appreciated, protein supplementation can augment resistance training-mediated gains in skeletal muscle mass even in individuals habitually consuming 'adequate' (i.e., >0.8 g kg⁻¹ day⁻¹) protein. Additionally, overfeeding energy with moderate to high-protein intake (15-25 % protein or 1.8-3.0 g kg⁻¹ day⁻¹) is associated with lean, but not fat mass accretion, when compared to overfeeding energy with low protein intake (5 % protein or ~0.68 g kg⁻¹ day⁻¹). Amino acids represent primary nutrient regulators of skeletal muscle anabolism, capable of enhancing lean mass accretion with resistance exercise and attenuating the loss of lean mass during periods of energy deficit, although factors such as protein dose, protein source, and timing of intake are likely important in mediating these effects.

  6. Scaling and Accommodation of Jaw Adductor Muscles in Canidae

    PubMed Central

    Kemp, Graham J.; Jeffery, Nathan

    2016-01-01

    ABSTRACT The masticatory apparatus amongst closely related carnivoran species raises intriguing questions about the interplay between allometry, function, and phylogeny in defining interspecific variations of cranial morphology. Here we describe the gross structure of the jaw adductor muscles of several species of canid, and then examine how the muscles are scaled across the range of body sizes, phylogenies, and trophic groups. We also consider how the muscles are accommodated on the skull, and how this is influenced by differences of endocranial size. Data were collected for a suite of morphological metrics, including body mass, endocranial volume, and muscle masses and we used geometric morphometric shape analysis to reveal associated form changes. We find that all jaw adductor muscles scale isometrically against body mass, regardless of phylogeny or trophic group, but that endocranial volume scales with negative allometry against body mass. These findings suggest that head shape is partly influenced by the need to house isometrically scaling muscles on a neurocranium scaling with negative allometry. Principal component analysis suggests that skull shape changes, such as the relatively wide zygomatic arches and large sagittal crests seen in species with higher body masses, allow the skull to accommodate a relative enlargement of the jaw adductors compared with the endocranium. Anat Rec, 299:951–966, 2016. © 2016 The Authors The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology Published by Wiley Periodicals, Inc. PMID:27103346

  7. Jasminum flexile flower absolute from India--a detailed comparison with three other jasmine absolutes.

    PubMed

    Braun, Norbert A; Kohlenberg, Birgit; Sim, Sherina; Meier, Manfred; Hammerschmidt, Franz-Josef

    2009-09-01

    Jasminum flexile flower absolute from the south of India and the corresponding vacuum headspace (VHS) sample of the absolute were analyzed using GC and GC-MS. Three other commercially available Indian jasmine absolutes from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower absolute, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed.

  8. A Simple Watt Balance for the Absolute Determination of Mass

    ERIC Educational Resources Information Center

    Quinn, Terry; Quinn, Lucas; Davis, Richard

    2013-01-01

    A watt balance is an electromechanical device that allows a mass to be determined in terms of measurable electrical and mechanical quantities, themselves traceable to the fundamental constants of physics. International plans are well advanced to redefine the unit of mass, the kilogram, in terms of a fixed numerical value for the Planck constant. A…

  9. Amino Acid Sensing in Skeletal Muscle

    PubMed Central

    Moro, Tatiana; Ebert, Scott M.; Adams, Christopher M.; Rasmussen, Blake B.

    2016-01-01

    Aging impairs skeletal muscle protein synthesis, leading to muscle weakness and atrophy. However, the underlying molecular mechanisms remain poorly understood. Here, we review evidence that mTORC1- and ATF4-mediated amino acid sensing pathways, triggered by impaired amino acid delivery to aged skeletal muscle, may play important roles in skeletal muscle aging. Interventions that alleviate age-related impairments in muscle protein synthesis, strength and/or muscle mass appear to do so by reversing age-related changes in skeletal muscle amino acid delivery, mTORC1 activity and/or ATF4 activity. An improved understanding of the mechanisms and roles of amino acid sensing pathways in skeletal muscle may lead to evidence-based strategies to attenuate sarcopenia. PMID:27444066

  10. Validating the absolute reliability of a fat free mass estimate equation in hemodialysis patients using near-infrared spectroscopy.

    PubMed

    Kono, Kenichi; Nishida, Yusuke; Moriyama, Yoshihumi; Taoka, Masahiro; Sato, Takashi

    2015-06-01

    The assessment of nutritional states using fat free mass (FFM) measured with near-infrared spectroscopy (NIRS) is clinically useful. This measurement should incorporate the patient's post-dialysis weight ("dry weight"), in order to exclude the effects of any change in water mass. We therefore used NIRS to investigate the regression, independent variables, and absolute reliability of FFM in dry weight. The study included 47 outpatients from the hemodialysis unit. Body weight was measured before dialysis, and FFM was measured using NIRS before and after dialysis treatment. Multiple regression analysis was used to estimate the FFM in dry weight as the dependent variable. The measured FFM before dialysis treatment (Mw-FFM), and the difference between measured and dry weight (Mw-Dw) were independent variables. We performed Bland-Altman analysis to detect errors between the statistically estimated FFM and the measured FFM after dialysis treatment. The multiple regression equation to estimate the FFM in dry weight was: Dw-FFM = 0.038 + (0.984 × Mw-FFM) + (-0.571 × [Mw-Dw]); R(2)  = 0.99). There was no systematic bias between the estimated and the measured values of FFM in dry weight. Using NIRS, FFM in dry weight can be calculated by an equation including FFM in measured weight and the difference between the measured weight and the dry weight. © 2015 The Authors. Therapeutic Apheresis and Dialysis © 2015 International Society for Apheresis.

  11. Physical frailty in older adults is associated with metabolic and atherosclerotic risk factors and cognitive impairment independent of muscle mass.

    PubMed

    Lee, J S W; Auyeung, T-W; Leung, J; Kwok, T; Leung, P-C; Woo, J

    2011-12-01

    Metabolic and atherosclerotic diseases are known risk factors for disability in old age, and can result in sarcopenia as well as cognitive impairment, which are both components of frailty syndrome. As muscle loss increases with ageing, it is unclear whether muscle loss per se, or the diseases themselves, are the underlying cause of physical frailty in those suffering from these diseases. We tested the hypothesis that metabolic and atherosclerotic diseases and cognitive impairment are associated with physical frailty independent of muscle loss in old age, and further examined their impact on the relationship between physical frailty and mortality. Prospective. Community. 4000 community dwelling Chinese elderly ≥65 years. Diabetes, hypertension, stroke, heart disease, cognitive impairment, smoking, physical activity, waist hip ratio (WHR) and ankle-brachial index (ABI)) were recorded. Physical frailty measurements (grip-strength, chair-stands, stride length and 6-metre walks) were summarized into a composite frailty score (0-20), 0 being the most frail) according to quartiles of performance. Appendicular muscle mass (ASM) was measured using dual X-ray absorptiometry. Relationships between the score and covariates were analyzed. Cox regression was used to study the impact of metabolic and atnerosclerotic risk factors on the relationship between physical frailty and 6-year mortality. After adjustment for ASM, all metabolic diseases and indexes, and cognitive impairment were significantly associated with the composite physical frailty score in univariate analysis. In multivariate analysis, cognitive impairment, high WHR, diabetes, stroke and heart disease were all independently associated with higher physical frailty with adjustment for age, physical activity level and ASM. Hypertension was associated with physical frailty in men but not in women. In Cox regression, increased physical frailty was associated with higher 6-year mortality. The impact of metabolic and

  12. Characteristics of locomotion, muscle strength, and muscle tissue in regenerating rat skeletal muscles.

    PubMed

    Iwata, Akira; Fuchioka, Satoshi; Hiraoka, Koichi; Masuhara, Mitsuhiko; Kami, Katsuya

    2010-05-01

    Although numerous studies have aimed to elucidate the mechanisms used to repair the structure and function of injured skeletal muscles, it remains unclear how and when movement recovers following damage. We performed a temporal analysis to characterize the changes in movement, muscle function, and muscle structure after muscle injury induced by the drop-mass technique. At each time-point, movement recovery was determined by ankle kinematic analysis of locomotion, and functional recovery was represented by isometric force. As a histological analysis, the cross-sectional area of myotubes was measured to examine structural regeneration. The dorsiflexion angle of the ankle, as assessed by kinematic analysis of locomotion, increased after injury and then returned to control levels by day 14 post-injury. The isometric force returned to normal levels by day 21 post-injury. However, the size of the myotubes did not reach normal levels, even at day 21 post-injury. These results indicate that recovery of locomotion occurs prior to recovery of isometric force and that functional recovery occurs earlier than structural regeneration. Thus, it is suggested that recovery of the movement and function of injured skeletal muscles might be insufficient as markers for estimating the degree of neuromuscular system reconstitution.

  13. Effect of Mass Flow on Stack Eductor Performance.

    DTIC Science & Technology

    1984-06-01

    absolute viscosity, lbf-sec/ft2 - density, Ibm/ft 3 "function of" ENGLISH LETTER SYMBOLS 2 A - area, in , ft B - atmospheric pressure, in Hg c - sonic... absolute temperature ratio T* - tertiary flow to primary flow absolute temperature t ratio - secondary -o primary mass flow rate ratio W* - tertiary to...secondary to primary absolute Tp temperature ratio TiL tertiary to primary absolute -TE temperature ratio secondary to primary flow density ratio

  14. Body mass reduction markedly improves muscle performance and body composition in obese females aged 61-75 years: comparison between the effects exerted by energy-restricted diet plus moderate aerobic-strength training alone or associated with rGH or nandrolone undecanoate.

    PubMed

    Sartorio, Alessandro; Maffiuletti, Nicola A; Agosti, Fiorenza; Marinone, Pier Giulio; Ottolini, Saverio; Lafortuna, Claudio L

    2004-04-01

    To investigate the effectiveness of a body mass reduction programme entailing diet caloric restriction and moderate physical activity with or without supplementary treatment with recombinant (r) GH or steroids to improve body composition and muscle performance in severely obese women aged 61-75 years. Twenty women were randomly assigned to one of three groups: body mass reduction alone; body mass reduction plus rGH; body mass reduction plus nandrolone undecanoate. Body composition, isotonic muscle strength and anaerobic power output during jumping were determined before and after the 3-week period. Whatever the experimental group considered, body mass (P<0.01), body mass index (P<0.05) and fat mass (P<0.05) decreased significantly, whereas muscle strength and power increased significantly (P<0.05) after the intervention. Small body mass reductions after 3 weeks of energy-restricted diet combined with moderate aerobic and strength exercise are associated with significant improvements in upper and lower limb muscle strength and power and reduction of fat mass in severely obese women aged 61-75 years. Although the association of rGH or nandrolone undecanoate does not appear to exert additional effects on body composition and muscle performance attained by body mass reduction alone, further additional studies with larger study groups, different dosages and more prolonged periods are required for definitive conclusions to be drawn.

  15. Catechins activate muscle stem cells by Myf5 induction and stimulate muscle regeneration.

    PubMed

    Kim, A Rum; Kim, Kyung Min; Byun, Mi Ran; Hwang, Jun-Ha; Park, Jung Il; Oh, Ho Taek; Kim, Hyo Kyeong; Jeong, Mi Gyeong; Hwang, Eun Sook; Hong, Jeong-Ho

    2017-07-22

    Muscle weakness is one of the most common symptoms in aged individuals and increases risk of mortality. Thus, maintenance of muscle mass is important for inhibiting aging. In this study, we investigated the effect of catechins, polyphenol compounds in green tea, on muscle regeneration. We found that (-)-epicatechin gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) activate satellite cells by induction of Myf5 transcription factors. For satellite cell activation, Akt kinase was significantly induced after ECG treatment and ECG-induced satellite cell activation was blocked in the presence of Akt inhibitor. ECG also promotes myogenic differentiation through the induction of myogenic markers, including Myogenin and Muscle creatine kinase (MCK), in satellite and C2C12 myoblast cells. Finally, EGCG administration to mice significantly increased muscle fiber size for regeneration. Taken together, the results suggest that catechins stimulate muscle stem cell activation and differentiation for muscle regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Muscle and bone follow similar temporal patterns of recovery from muscle-induced disuse due to botulinum toxin injection.

    PubMed

    Manske, Sarah L; Boyd, Steven K; Zernicke, Ronald F

    2010-01-01

    If muscle force is a primary source for triggering bone adaptation, with disuse and reloading, bone changes should follow muscle changes. We examined the timing and magnitude of changes in muscle cross-sectional area (MCSA) and bone architecture in response to muscle inactivity following botulinum toxin (BTX) injection. We hypothesized that MCSA would return to baseline levels sooner than bone properties following BTX injection. Female BALB mice (15 weeks old) were injected with 20 muL of BTX (1 U/100 g body mass, n=18) or saline (SAL, n=18) into the posterior calf musculature of one limb. The contralateral limb (CON) served as an internal control. MCSA and bone properties were assessed at baseline, 2, 4, 8, 12, and 16 weeks post-injection using in vivo micro-CT at the tibia proximal metaphysis (bone only) and diaphysis. Muscles were dissected and weighed after sacrifice. Significant GroupxLegxTime interactions indicated that the maximal decrease in MCSA (56%), proximal metaphyseal BV/TV (38%) and proximal diaphyseal Ct.Ar (7%) occurred 4 weeks after injection. There was no delay prior to bone recovery as both muscle and bone properties began to recover after this time, but MCSA and BV/TV remained 15% and 20% lower, respectively, in the BTX-injected leg than the BTX-CON leg 16 weeks post-injection. Gastrocnemius mass (primarily fast-twitch) was 14% lower in the BTX-injected leg than the SAL-injected leg, while soleus mass (primarily slow-twitch) was 15% greater in the BTX group than the SAL group. Our finding that muscle size and bone began to recover at similar times after BTX injection was unexpected. This suggested that partial weight-bearing and/or return of slow-twitch muscle activity in the BTX leg may have been sufficient to stimulate bone recovery. Alternatively, muscle function may have recovered sooner than MCSA. Our results indicated that muscle cross-sectional area, while important, may not be the primary factor associated with bone loss and recovery

  17. The relationships among jaw-muscle fiber architecture, jaw morphology, and feeding behavior in extant apes and modern humans.

    PubMed

    Taylor, Andrea B; Vinyard, Christopher J

    2013-05-01

    The jaw-closing muscles are responsible for generating many of the forces and movements associated with feeding. Muscle physiologic cross-sectional area (PCSA) and fiber length are two architectural parameters that heavily influence muscle function. While there have been numerous comparative studies of hominoid and hominin craniodental and mandibular morphology, little is known about hominoid jaw-muscle fiber architecture. We present novel data on masseter and temporalis internal muscle architecture for small- and large-bodied hominoids. Hominoid scaling patterns are evaluated and compared with representative New- (Cebus) and Old-World (Macaca) monkeys. Variation in hominoid jaw-muscle fiber architecture is related to both absolute size and allometry. PCSAs scale close to isometry relative to jaw length in anthropoids, but likely with positive allometry in hominoids. Thus, large-bodied apes may be capable of generating both absolutely and relatively greater muscle forces compared with smaller-bodied apes and monkeys. Compared with extant apes, modern humans exhibit a reduction in masseter PCSA relative to condyle-M1 length but retain relatively long fibers, suggesting humans may have sacrificed relative masseter muscle force during chewing without appreciably altering muscle excursion/contraction velocity. Lastly, craniometric estimates of PCSAs underestimate hominoid masseter and temporalis PCSAs by more than 50% in gorillas, and overestimate masseter PCSA by as much as 30% in humans. These findings underscore the difficulty of accurately estimating jaw-muscle fiber architecture from craniometric measures and suggest models of fossil hominin and hominoid bite forces will be improved by incorporating architectural data in estimating jaw-muscle forces. Copyright © 2013 Wiley Periodicals, Inc.

  18. Quaternary ammonium isobaric tag for a relative and absolute quantification of peptides.

    PubMed

    Setner, Bartosz; Stefanowicz, Piotr; Szewczuk, Zbigniew

    2018-02-01

    Isobaric labeling quantification of peptides has become a method of choice for mass spectrometry-based proteomics studies. However, despite of wide variety of commercially available isobaric tags, none of the currently available methods offers significant improvement of sensitivity of detection during MS experiment. Recently, many strategies were applied to increase the ionization efficiency of peptides involving chemical modifications introducing quaternary ammonium fixed charge. Here, we present a novel quaternary ammonium-based isobaric tag for relative and absolute quantification of peptides (QAS-iTRAQ 2-plex). Upon collisional activation, the new stable benzylic-type cationic reporter ion is liberated from the tag. Deuterium atoms were used to offset the differential masses of a reporter group. We tested the applicability of QAS-iTRAQ 2-plex reagent on a series of model peptides as well as bovine serum albumin tryptic digest. Obtained results suggest usefulness of this isobaric ionization tag for relative and absolute quantification of peptides. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Diminished skeletal muscle microRNA expression with aging is associated with attenuated muscle plasticity and inhibition of IGF-1 signaling

    USDA-ARS?s Scientific Manuscript database

    Older individuals have a reduced capacity to induce muscle hypertrophy with resistance exercise (RE), which may contribute to the age-induced loss of muscle mass and function, sarcopenia. We tested the novel hypothesis that dysregulation of microRNAs (miRNAs) may contribute to reduced muscle plastic...

  20. Spermine oxidase maintains basal skeletal muscle gene expression and fiber size and is strongly repressed by conditions that cause skeletal muscle atrophy

    PubMed Central

    Bongers, Kale S.; Fox, Daniel K.; Kunkel, Steven D.; Stebounova, Larissa V.; Murry, Daryl J.; Pufall, Miles A.; Ebert, Scott M.; Dyle, Michael C.; Bullard, Steven A.; Dierdorff, Jason M.

    2014-01-01

    Skeletal muscle atrophy is a common and debilitating condition that remains poorly understood at the molecular level. To better understand the mechanisms of muscle atrophy, we used mouse models to search for a skeletal muscle protein that helps to maintain muscle mass and is specifically lost during muscle atrophy. We discovered that diverse causes of muscle atrophy (limb immobilization, fasting, muscle denervation, and aging) strongly reduced expression of the enzyme spermine oxidase. Importantly, a reduction in spermine oxidase was sufficient to induce muscle fiber atrophy. Conversely, forced expression of spermine oxidase increased muscle fiber size in multiple models of muscle atrophy (immobilization, fasting, and denervation). Interestingly, the reduction of spermine oxidase during muscle atrophy was mediated by p21, a protein that is highly induced during muscle atrophy and actively promotes muscle atrophy. In addition, we found that spermine oxidase decreased skeletal muscle mRNAs that promote muscle atrophy (e.g., myogenin) and increased mRNAs that help to maintain muscle mass (e.g., mitofusin-2). Thus, in healthy skeletal muscle, a relatively low level of p21 permits expression of spermine oxidase, which helps to maintain basal muscle gene expression and fiber size; conversely, during conditions that cause muscle atrophy, p21 expression rises, leading to reduced spermine oxidase expression, disruption of basal muscle gene expression, and muscle fiber atrophy. Collectively, these results identify spermine oxidase as an important positive regulator of muscle gene expression and fiber size, and elucidate p21-mediated repression of spermine oxidase as a key step in the pathogenesis of skeletal muscle atrophy. PMID:25406264