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David Bendahan - One of the best experts on this subject based on the ideXlab platform.
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radio frequency coil for dual nuclei mr Muscle Energetics investigation based on two capacitively coupled periodic wire arrays
IEEE Antennas and Wireless Propagation Letters, 2020Co-Authors: Anna Hurshkainen, Marc Dubois, A Nikulin, Christophe Vilmen, David Bendahan, Stefan Enoch, Stanislav Glybovski, Redha AbdeddaimAbstract:In this letter, we describe a dedicated radio frequency (RF) coil for magnetic resonance imaging and spectroscopy at 4.7 T optimized for investigation of Muscle Energetics in a human forearm. The coil operating at the Larmor frequencies of protons $^1$ H (200.1 MHz) and phosphorous $^{31}$ P (81 MHz) is based on two cylindrical periodic structures made of thin metal wires with tips interconnected through structural capacities of printed overlapping patches and sliding electric contacts. By independently exciting two orthogonal eigenmodes of the structure, the coil can be tuned and matched at both frequencies without lumped capacitors and cover the target region of interest for the forearm flexor Muscles.
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role of mct1 and caii in skeletal Muscle ph homeostasis Energetics and function in vivo insights from mct1 haploinsufficient mice
The FASEB Journal, 2017Co-Authors: Benjamin Chatel, David Bendahan, Yann Le Fur, Christophe Hourde, Luc Pellerin, Sylvain Lengacher, Pierre J Magistretti, Christophe VilmenAbstract:The purpose of this study was to investigate the effects of a partial suppression of monocarboxylate transporter (MCT)-1 on skeletal Muscle pH, Energetics, and function (MCT1+/- mice). Twenty-four MCT1+/- and 13 wild-type (WT) mice were subjected to a rest-exercise-recovery protocol, allowing assessment of Muscle Energetics (by magnetic resonance spectroscopy) and function. The study included analysis of enzyme activities and content of protein involved in pH regulation. Skeletal Muscle of MCT1+/- mice had lower MCT1 (-61%; P < 0.05) and carbonic anhydrase (CA)-II (-54%; P < 0.05) contents. Although intramuscular pH was higher in MCT1+/- mice at rest (P < 0.001), the mice showed higher acidosis during the first minute of exercise (P < 0.01). Then, the pH time course was similar among groups until exercise completion. MCT1+/- mice had higher specific peak (P < 0.05) and maximum tetanic (P < 0.01) forces and lower fatigability (P < 0.001) when compared to WT mice. We conclude that both MCT1 and CAII are involved in the homeostatic control of pH in skeletal Muscle, both at rest and at the onset of exercise. The improved Muscle function and resistance to fatigue in MCT1+/- mice remain unexplained.-Chatel, B., Bendahan, D., Hourde, C., Pellerin, L., Lengacher, S., Magistretti, P., Fur, Y. L., Vilmen, C., Bernard, M., Messonnier, L. A. Role of MCT1 and CAII in skeletal Muscle pH homeostasis, Energetics, and function: in vivo insights from MCT1 haploinsufficient mice.
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effects of branched chain amino acids supplementation on both plasma amino acids concentration and Muscle Energetics changes resulting from Muscle damage a randomized placebo controlled trial
Clinical Nutrition, 2016Co-Authors: Alexandre Foure, Christophe Vilmen, David Bendahan, Jeanpierre Mattei, Yann Le Fur, Helene Boudinet, Kazunori Nosaka, Marguerite Gastaldi, Maxime Guye, Julien GondinAbstract:summary Background & aims: Branched-chain amino acids promote Muscle-protein synthesis, reduce protein oxidation and have positive effects on mitochondrial biogenesis and reactive oxygen species scavenging. The purpose of the study was to determine the potential benefits of branched-chain amino acids supplementation on changes in force capacities, plasma amino acids concentration and Muscle metabolic alterations after exercise-induced Muscle damage. Methods: 31 P magnetic resonance spectroscopy and biochemical analyses were used to follow the changes after such damage. Twenty six young healthy men were randomly assigned to supplemented branched-chain amino acids or placebo group. Knee extensors maximal voluntary isometric force was assessed before and on four days following exercise-induced Muscle damage. Concentrations in phosphocreatine [PCr], inorganic phosphate [Pi] and pH were measured during a standardized rest-exerciserecovery protocol before, two (D2) and four (D4) days after exercise-induced Muscle damage. Results: No significant difference between groups was found for changes in maximal voluntary isometric force (� 24% at D2 and � 21% at D4). Plasma alanine concentration significantly increased immediately after exercise-induced Muscle damage (þ25%) in both groups while concentrations in glycine, histidine, phenylalanine and tyrosine decreased. No difference between groups was found in the increased resting [Pi] (þ42% at D2 and þ34% at D4), decreased resting pH (� 0.04 at D2 and � 0.03 at D4) and the slower PCr recovery rate (� 18% at D2 and � 24% at D4). Conclusions: The damaged Muscle was not able to get benefits out of the increased plasma branchedchain amino acids availability to attenuate changes in indirect markers of Muscle damage and Muscle
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impaired mitochondrial function and reduced energy cost as a result of Muscle damage
Medicine and Science in Sports and Exercise, 2015Co-Authors: Alexandre Foure, Christophe Vilmen, David Bendahan, Jeanpierre Mattei, Yann Le Fur, Jennifer Wegrzyk, Helene Boudinet, Julien GondinAbstract:AB Purpose: Although it has been largely acknowledged that isometric neuromuscular electrostimulation (NMES) exercise induces larger Muscle damage than voluntary contractions, the corresponding effects on Muscle Energetics remain to be determined. Voluntary exercise-induced Muscle damage (EIMD) has been reported to have minor slight effects on Muscle metabolic response to subsequent dynamic exercise, but the magnitude of Muscle Energetics alterations for NMES EIMD has never been documented. Methods: 31P magnetic resonance spectroscopy measurements were performed in 13 young healthy males during a standardized rest-exercise-recovery protocol before (D0) and 2 d (D2) and 4 d (D4) after NMES EIMD on knee extensor Muscles. Changes in kinetics of phosphorylated metabolite concentrations (i.e., phosphocreatine [PCr], inorganic phosphate [Pi], and adenosine triphosphate [ATP]) and pH were assessed to investigate aerobic and anaerobic rates of ATP production and energy cost of contraction (Ec). Results: Resting [Pi]/[PCr] ratio increased at D2 (+39%) and D4 (+29%), mainly owing to the increased [Pi] (+43% and +32%, respectively), whereas a significant decrease in resting pH was determined (-0.04 pH unit and -0.03 pH unit, respectively). PCr recovery rate decreased at D2 (-21%) and D4 (-23%) in conjunction with a significantly decreased total rate of ATP production at D4 (-18%) mainly owing to an altered aerobic ATP production (-19%). Paradoxically, Ec was decreased at D4 (-21%). Conclusion: Overall, NMES EIMD led to intramuscular acidosis in resting Muscle and mitochondrial impairment in exercising Muscle. Alterations of noncontractile processes and/or adaptive mechanisms to Muscle damage might account for the decreased Ec during the dynamic exercise
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Muscle Energetics changes throughout maturation a quantitative 31p mrs analysis
Journal of Applied Physiology, 2010Co-Authors: Anne Tonson, Christophe Vilmen, Patrick J Cozzone, Sebastien Ratel, Yann Le Fur, David BendahanAbstract:We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using 31P-magnetic resonance spectroscopy to investigate whether development affects Muscle energet...
Votion Dominique - One of the best experts on this subject based on the ideXlab platform.
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Le profil des acylcarnitines prédit la survie chez les chevaux souffrant de myopathie atypique
'Public Library of Science (PLoS)', 2017Co-Authors: Boemer François, Detilleux Johann, Cello Christophe, Amory Hélène, Marcillaud-pitel Christel, Richard Eric, Van Galen Gaby, Van Loon Gunther, Lefère Laurence, Votion DominiqueAbstract:peer reviewedaudience: researcher, professionalEquine atypical myopathy (AM) is caused by hypoglycin A intoxication and is characterized by a high fatality rate. Predictive estimation of survival in AM horses is necessary to prevent unnecessary suffering of animals that are unlikely to survive and to focus supportive therapy on horses with a possible favourable prognosis of survival. We hypothesized that outcome may be predicted early in the course of disease based on the assumption that the acylcarnitine profile reflects the derangement of Muscle Energetics. We developed a statistical model to prognosticate the risk of death of diseased animals and found that estimation of outcome may be drawn from three acylcarnitines (C2, C10:2 and C18 -carnitines) with a high sensitivity and specificity. The calculation of the prognosis of survival makes it possible to distinguish the horses that will survive from those that will die despite severe sign of acute rhabdomyolysis in both group
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Le profil des acylcarnitines prédit la survie chez les chevaux souffrant de myopathie atypique
'Public Library of Science (PLoS)', 2017Co-Authors: Boemer François, Detilleux Johann, Cello Christophe, Amory Hélène, Marcillaud-pitel Christel, Richard Eric, Van Galen Gaby, Van Loon Gunther, Lefère Laurence, Votion DominiqueAbstract:Equine atypical myopathy (AM) is caused by hypoglycin A intoxication and is characterized by a high fatality rate. Predictive estimation of survival in AM horses is necessary to prevent unnecessary suffering of animals that are unlikely to survive and to focus supportive therapy on horses with a possible favourable prognosis of survival. We hypothesized that outcome may be predicted early in the course of disease based on the assumption that the acylcarnitine profile reflects the derangement of Muscle Energetics. We developed a statistical model to prognosticate the risk of death of diseased animals and found that estimation of outcome may be drawn from three acylcarnitines (C2, C10:2 and C18 -carnitines) with a high sensitivity and specificity. The calculation of the prognosis of survival makes it possible to distinguish the horses that will survive from those that will die despite severe sign of acute rhabdomyolysis in both groupsPeer reviewe
Christophe Vilmen - One of the best experts on this subject based on the ideXlab platform.
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radio frequency coil for dual nuclei mr Muscle Energetics investigation based on two capacitively coupled periodic wire arrays
IEEE Antennas and Wireless Propagation Letters, 2020Co-Authors: Anna Hurshkainen, Marc Dubois, A Nikulin, Christophe Vilmen, David Bendahan, Stefan Enoch, Stanislav Glybovski, Redha AbdeddaimAbstract:In this letter, we describe a dedicated radio frequency (RF) coil for magnetic resonance imaging and spectroscopy at 4.7 T optimized for investigation of Muscle Energetics in a human forearm. The coil operating at the Larmor frequencies of protons $^1$ H (200.1 MHz) and phosphorous $^{31}$ P (81 MHz) is based on two cylindrical periodic structures made of thin metal wires with tips interconnected through structural capacities of printed overlapping patches and sliding electric contacts. By independently exciting two orthogonal eigenmodes of the structure, the coil can be tuned and matched at both frequencies without lumped capacitors and cover the target region of interest for the forearm flexor Muscles.
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role of mct1 and caii in skeletal Muscle ph homeostasis Energetics and function in vivo insights from mct1 haploinsufficient mice
The FASEB Journal, 2017Co-Authors: Benjamin Chatel, David Bendahan, Yann Le Fur, Christophe Hourde, Luc Pellerin, Sylvain Lengacher, Pierre J Magistretti, Christophe VilmenAbstract:The purpose of this study was to investigate the effects of a partial suppression of monocarboxylate transporter (MCT)-1 on skeletal Muscle pH, Energetics, and function (MCT1+/- mice). Twenty-four MCT1+/- and 13 wild-type (WT) mice were subjected to a rest-exercise-recovery protocol, allowing assessment of Muscle Energetics (by magnetic resonance spectroscopy) and function. The study included analysis of enzyme activities and content of protein involved in pH regulation. Skeletal Muscle of MCT1+/- mice had lower MCT1 (-61%; P < 0.05) and carbonic anhydrase (CA)-II (-54%; P < 0.05) contents. Although intramuscular pH was higher in MCT1+/- mice at rest (P < 0.001), the mice showed higher acidosis during the first minute of exercise (P < 0.01). Then, the pH time course was similar among groups until exercise completion. MCT1+/- mice had higher specific peak (P < 0.05) and maximum tetanic (P < 0.01) forces and lower fatigability (P < 0.001) when compared to WT mice. We conclude that both MCT1 and CAII are involved in the homeostatic control of pH in skeletal Muscle, both at rest and at the onset of exercise. The improved Muscle function and resistance to fatigue in MCT1+/- mice remain unexplained.-Chatel, B., Bendahan, D., Hourde, C., Pellerin, L., Lengacher, S., Magistretti, P., Fur, Y. L., Vilmen, C., Bernard, M., Messonnier, L. A. Role of MCT1 and CAII in skeletal Muscle pH homeostasis, Energetics, and function: in vivo insights from MCT1 haploinsufficient mice.
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effects of branched chain amino acids supplementation on both plasma amino acids concentration and Muscle Energetics changes resulting from Muscle damage a randomized placebo controlled trial
Clinical Nutrition, 2016Co-Authors: Alexandre Foure, Christophe Vilmen, David Bendahan, Jeanpierre Mattei, Yann Le Fur, Helene Boudinet, Kazunori Nosaka, Marguerite Gastaldi, Maxime Guye, Julien GondinAbstract:summary Background & aims: Branched-chain amino acids promote Muscle-protein synthesis, reduce protein oxidation and have positive effects on mitochondrial biogenesis and reactive oxygen species scavenging. The purpose of the study was to determine the potential benefits of branched-chain amino acids supplementation on changes in force capacities, plasma amino acids concentration and Muscle metabolic alterations after exercise-induced Muscle damage. Methods: 31 P magnetic resonance spectroscopy and biochemical analyses were used to follow the changes after such damage. Twenty six young healthy men were randomly assigned to supplemented branched-chain amino acids or placebo group. Knee extensors maximal voluntary isometric force was assessed before and on four days following exercise-induced Muscle damage. Concentrations in phosphocreatine [PCr], inorganic phosphate [Pi] and pH were measured during a standardized rest-exerciserecovery protocol before, two (D2) and four (D4) days after exercise-induced Muscle damage. Results: No significant difference between groups was found for changes in maximal voluntary isometric force (� 24% at D2 and � 21% at D4). Plasma alanine concentration significantly increased immediately after exercise-induced Muscle damage (þ25%) in both groups while concentrations in glycine, histidine, phenylalanine and tyrosine decreased. No difference between groups was found in the increased resting [Pi] (þ42% at D2 and þ34% at D4), decreased resting pH (� 0.04 at D2 and � 0.03 at D4) and the slower PCr recovery rate (� 18% at D2 and � 24% at D4). Conclusions: The damaged Muscle was not able to get benefits out of the increased plasma branchedchain amino acids availability to attenuate changes in indirect markers of Muscle damage and Muscle
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impaired mitochondrial function and reduced energy cost as a result of Muscle damage
Medicine and Science in Sports and Exercise, 2015Co-Authors: Alexandre Foure, Christophe Vilmen, David Bendahan, Jeanpierre Mattei, Yann Le Fur, Jennifer Wegrzyk, Helene Boudinet, Julien GondinAbstract:AB Purpose: Although it has been largely acknowledged that isometric neuromuscular electrostimulation (NMES) exercise induces larger Muscle damage than voluntary contractions, the corresponding effects on Muscle Energetics remain to be determined. Voluntary exercise-induced Muscle damage (EIMD) has been reported to have minor slight effects on Muscle metabolic response to subsequent dynamic exercise, but the magnitude of Muscle Energetics alterations for NMES EIMD has never been documented. Methods: 31P magnetic resonance spectroscopy measurements were performed in 13 young healthy males during a standardized rest-exercise-recovery protocol before (D0) and 2 d (D2) and 4 d (D4) after NMES EIMD on knee extensor Muscles. Changes in kinetics of phosphorylated metabolite concentrations (i.e., phosphocreatine [PCr], inorganic phosphate [Pi], and adenosine triphosphate [ATP]) and pH were assessed to investigate aerobic and anaerobic rates of ATP production and energy cost of contraction (Ec). Results: Resting [Pi]/[PCr] ratio increased at D2 (+39%) and D4 (+29%), mainly owing to the increased [Pi] (+43% and +32%, respectively), whereas a significant decrease in resting pH was determined (-0.04 pH unit and -0.03 pH unit, respectively). PCr recovery rate decreased at D2 (-21%) and D4 (-23%) in conjunction with a significantly decreased total rate of ATP production at D4 (-18%) mainly owing to an altered aerobic ATP production (-19%). Paradoxically, Ec was decreased at D4 (-21%). Conclusion: Overall, NMES EIMD led to intramuscular acidosis in resting Muscle and mitochondrial impairment in exercising Muscle. Alterations of noncontractile processes and/or adaptive mechanisms to Muscle damage might account for the decreased Ec during the dynamic exercise
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Muscle Energetics changes throughout maturation a quantitative 31p mrs analysis
Journal of Applied Physiology, 2010Co-Authors: Anne Tonson, Christophe Vilmen, Patrick J Cozzone, Sebastien Ratel, Yann Le Fur, David BendahanAbstract:We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using 31P-magnetic resonance spectroscopy to investigate whether development affects Muscle energet...
Patrick J Cozzone - One of the best experts on this subject based on the ideXlab platform.
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Muscle Energetics changes throughout maturation a quantitative 31p mrs analysis
Journal of Applied Physiology, 2010Co-Authors: Anne Tonson, Christophe Vilmen, Patrick J Cozzone, Sebastien Ratel, Yann Le Fur, David BendahanAbstract:We quantified energy production in 7 prepubescent boys (11.7 ± 0.6 yr) and 10 men (35.6 ± 7.8 yr) using 31P-magnetic resonance spectroscopy to investigate whether development affects Muscle energet...
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reproducibility assessment of metabolic variables characterizing Muscle Energetics in vivo a 31p mrs study
Magnetic Resonance in Medicine, 2009Co-Authors: Gwenael Layec, Christophe Vilmen, Patrick J Cozzone, Yann Le Fur, Aurelien Bringard, J P Micallef, Stephane Perrey, David BendahanAbstract:The purpose of the present study was to assess the reliability of metabolic parameters measured using 31P magnetic resonance spectroscopy (31P MRS) during two standardized rest-exercise-recovery protocols. Twelve healthy subjects performed the standardized protocols at two different intensities; i.e., a moderate intensity (MOD) repeated over a two-month period and heavy intensity (HEAVY) repeated over a year's time. Test-retest reliability was analyzed using coefficient of variation (CV), limits of agreement (LOA), and intraclass correlation coefficients (ICC). During exercise and recovery periods, most of the metabolic parameters exhibited a good reliability. The CVs of individual concentration of phosphocreatine ([PCr]), concentration of adenosine diphosphate ([ADP]), and pH values recorded at end of the HEAVY exercise were lower than 15%. The CV calculated for the rate of PCr resynthesis and the maximal oxidative capacity were less than 13% during the HEAVY protocol. Inferred parameters such as oxidative and total adenosine triphosphate (ATP) production rates exhibited a good reliability (ICC ≈ 0.7; CV < 15% during the HEAVY protocol). Our results demonstrated that measurement error using 31P-MRS during a standardized exercise was low and that biological variability accounted for the vast majority of the measurement variability. In addition, the corresponding metabolic measurements can reliably be used for longitudinal studies performed even over a long period of time. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc.
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does oxidative capacity affect energy cost an in vivo mr investigation of skeletal Muscle Energetics
European Journal of Applied Physiology, 2009Co-Authors: Gwenael Layec, Christophe Vilmen, Patrick J Cozzone, Yann Le Fur, Aurelien Bringard, J P Micallef, Stephane Perrey, David BendahanAbstract:Investigations of training effects on exercise energy cost have yielded conflicting results. The purpose of the present study was to compare quadriceps energy cost and oxidative capacity between endurance-trained and sedentary subjects during a heavy dynamic knee extension exercise. We quantified the rates of ATP turnover from oxidative and anaerobic pathways with 31P-MRS, and we measured simultaneously pulmonary oxygen uptake in order to assess both total ATP production [i.e., energy cost (EC)] and O2 consumption (O2 cost) scaled to power output. Seven sedentary (SED) and seven endurance-trained (TRA) subjects performed a dynamic standardized rest-exercise-recovery protocol at an exercise intensity corresponding to 35% of maximal voluntary contraction. We showed that during a dynamic heavy exercise, the O2 cost and EC were similar in the SED and endurance-trained groups. For a given EC, endurance-trained subjects exhibited a higher relative mitochondrial contribution to ATP production at the Muscle level (84 ± 12% in TRA and 57 ± 12% in SED; P < 0.01) whereas the anaerobic contribution was reduced (18 ± 12% in TRA and 44 ± 11% in SED; P < 0.01). Our results obtained in vivo illustrate that on the one hand the beneficial effects of endurance training are not related to any reduction in EC or O2 cost and on the other hand that this similar EC was linked to a change regarding the contribution of anaerobic and oxidative processes to energy production, i.e., a greater aerobic energy contribution associated with a concomitant reduction of the anaerobic energy supply.
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non invasive investigations of muscular fatigue metabolic and electromyographic components
Biochimie, 2003Co-Authors: Benoit Giannesini, Patrick J Cozzone, David BendahanAbstract:Muscle fatigue, which is defined as the decline in Muscle performance during exercise, may occur at different sites along the pathway from the central nervous system through to the intramuscular contractile machinery. Historically, both impairment of neuromuscular transmission and peripheral alterations within the Muscle have been proposed to be involved in the development of fatigue. However, according to the more recent studies, Muscle Energetics would have a key role in this process. Intramyoplasmic accumulation of inorganic phosphate (P(i)) and limitation in ATP availability are frequently proposed as the causative factors of fatigue development. Although attractive, these hypotheses have been elaborated on the basis of experimental results obtained in vitro and their physiological relevance has never been clearly demonstrated in vivo. In that context, non-invasive methods such as 31-phosphorus magnetic resonance spectroscopy ((31)P MRS) and electromyographic (EMG) recordings have been employed to understand both metabolic and electrical aspects of Muscle fatigue under physiological condition. The main results of these studies are reviewed in the present paper.
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a noninvasive investigation of Muscle Energetics supports similarities between exertional heat stroke and malignant hyperthermia
Anesthesia & Analgesia, 2001Co-Authors: David Bendahan, Genevi Ve Kozakribbens, Sylviane Confortgouny, Badih Ghattas, Dominique Figarellabranger, Michel Aubert, Patrick J CozzoneAbstract:Exertional heat stroke (EHS) is usually triggered by strenuous exercise performed under hot and humid environmental conditions. Although the pathogenesis of an EHS episode differs from that of a clinical malignant hyperthermia (MH) crisis, both conditions share some similarities in symptoms, such as
Lindsay M Edwards - One of the best experts on this subject based on the ideXlab platform.
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the reproducibility of 31 phosphorus mrs measures of Muscle Energetics at 3 tesla in trained men
PLOS ONE, 2012Co-Authors: Lindsay M Edwards, Damian J Tyler, Graham J Kemp, Cameron J Holloway, Renee M Dwyer, Andrew Johnson, Alan M Nevill, Kieran ClarkeAbstract:Objective Magnetic resonance spectroscopy (MRS) provides an exceptional opportunity for the study of in vivo metabolism. MRS is widely used to measure phosphorus metabolites in trained Muscle, although there are no published data regarding its reproducibility in this specialized cohort. Thus, the aim of this study was to assess the reproducibility of 31P-MRS in trained skeletal Muscle. Methods We recruited fifteen trained men (VO2peak = 4.7±0.8 L min−1/58±8 mL kg−1 min−1) and performed duplicate MR experiments during plantar flexion exercise, three weeks apart. Results Measures of resting phosphorus metabolites were reproducible, with 1.7 mM the smallest detectable difference in phosphocreatine (PCr). Measures of metabolites during exercise were less reliable: exercising PCr had a coefficient of variation (CV) of 27% during exercise, compared with 8% at rest. Estimates of mitochondrial function were variable, but experimentally useful. The CV of PCr1/2t was 40%, yet much of this variance was inter-subject such that differences of <20% were detectable with n = 15, given a significance threshold of p<0.05. Conclusions 31-phosphorus MRS provides reproducible and experimentally useful measures of phosphorus metabolites and mitochondrial function in trained human skeletal Muscle.
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the effect of high altitude on human skeletal Muscle Energetics 31p mrs results from the caudwell xtreme everest expedition
PLOS ONE, 2010Co-Authors: Lindsay M Edwards, Andrew J Murray, Damian J Tyler, Graham J Kemp, Cameron J Holloway, Peter A Robbins, Stefan Neubauer, Denny Z H LevettAbstract:Many disease states are associated with regional or systemic hypoxia. The study of healthy individuals exposed to high-altitude hypoxia offers a way to explore hypoxic adaptation without the confounding effects of disease and therapeutic interventions. Using 31P magnetic resonance spectroscopy and imaging, we investigated skeletal Muscle Energetics and morphology after exposure to hypobaric hypoxia in seven altitude-naive subjects (trekkers) and seven experienced climbers. The trekkers ascended to 5300 m while the climbers ascended above 7950 m. Before the study, climbers had better mitochondrial function (evidenced by shorter phosphocreatine recovery halftime) than trekkers: 16±1 vs. 22±2 s (mean ± SE, p<0.01). Climbers had higher resting [Pi] than trekkers before the expedition and resting [Pi] was raised across both groups on their return (PRE: 2.6±0.2 vs. POST: 3.0±0.2 mM, p<0.05). There was significant Muscle atrophy post-CXE (PRE: 4.7±0.2 vs. POST: 4.5±0.2 cm2, p<0.05), yet exercising metabolites were unchanged. These results suggest that, in response to high altitude hypoxia, skeletal Muscle function is maintained in humans, despite significant atrophy.
