Whey protein with potassium bicarbonate supplement attenuates the reduction in muscle oxidative capacity during 19 days bed rest.

The effectiveness of whey protein plus potassium bicarbonate enriched-diet (WP+KHCO3) to mitigate disuse-induced changes in muscle fibre oxidative capacity and capillarization was investigated in a 21-day crossover design bed rest study. Ten healthy men (31±6 years) once received WP+KHCO3 and once received a standardized isocaloric diet. Muscle biopsies were taken two days before and during the 19th day of bed rest (BR) from the soleus (SOL) and vastus lateralis (VL) muscle. Whole body aerobic power (VO2max), muscle fatigue and isometric strength of knee extensor and plantar flexor muscles were monitored. Muscle fiber types and capillaries were identified by immunohistochemistry. Fiber oxidative capacity was determined as the optical density (OD) at 660 nm of succinate dehydrogenase (SDH)-stained sections. The product of fiber cross-sectional area and SDH-OD (integrated SDH) indicated the maximal oxygen consumption of that fiber. The maximal oxygen consumption supported by a capillary was calculated as the integrated SDH in its supply area. BR reduced isometric strength of knee extensor muscles (P<0.05), and the fiber oxidative capacity (P<0.001) and VO2max (P=0.042), but had no significant impact on muscle capillarization or fatigue resistance of thigh muscles. The maximal oxygen consumption supported by a capillary was reduced by 24% in SOL and 16% in VL (P<0.001). WP+KHCO3 attenuated the disuse-induced reduction in fiber oxidative capacity in both muscles (P<0.01). In conclusion, following 19 days bed rest, the decrement in fiber oxidative capacity is proportionally larger than the loss of capillaries. WP+KHCO3 appears to attenuate disuse-induced reductions in fiber oxidative capacity

PPARα gene variation and physical performance in Russian athletes

Peroxisome proliferator-activated receptor α (PPARα) regulates genes responsible for skeletal and heart muscle fatty acid oxidation. Previous studies have shown that the PPARα intron 7 G/C polymorphism was associated with left ventricular growth in response to exercise. We speculated that GG homozygotes should be more prevalent within a group of endurance-oriented athletes, have normal fatty acid metabolism, and increased percentages of slow-twitch fibers. We have tested this hypothesis in the study of a mixed cohort of 786 Russian athletes in 13 different sporting disciplines prospectively stratified by performance (endurance-oriented athletes, power-oriented athletes and athletes with mixed endurance/power activity). PPARα intron 7 genotype and allele frequencies were compared to 1,242 controls. We found an increasing linear trend of C allele with increasing anaerobic component of physical performance (P=0.029). GG genotype frequencies in endurance-oriented and power-oriented athletes were 80.3 and 50.6%, respectively, and were significantly (P<0.0001) different compared to controls (70.0%). To examine the association between PPARα gene variant and fiber type composition, muscle biopsies from m. vastus lateralis were obtained and analyzed in 40 young men. GG homozygotes (n=25) had significantly (P=0.003) higher percentages of slow-twitch fibers (55.5±2.0 vs 38.5±2.3%) than CC homozygotes (n=4). In conclusion, PPARα intron 7 G/C polymorphism was associated with physical performance in Russian athletes, and this may be explained, in part, by the association between PPARα genotype and muscle fiber type composition. © Springer-Verlag 2006

Longitudinal evaluation the pulmonary function of the pre and postoperative periods in the coronary artery bypass graft surgery of patients treated with a physiotherapy protocol

<p>Abstract</p> <p>Background</p> <p>The treatment of coronary artery disease (CAD) seeks to reduce or prevent its complications and decrease morbidity and mortality. For certain subgroups of patients, coronary artery bypass graft surgery (CABG) may accomplish these goals. The objective of this study was to assess the pulmonary function in the CABG postoperative period of patients treated with a physiotherapy protocol.</p> <p>Methods</p> <p>Forty-two volunteers with an average age of 63 ± 2 years were included and separated into three groups: healthy volunteers (n = 09), patients with CAD (n = 9) and patients who underwent CABG (n = 20). Patients from the CABG group received preoperative and postoperative evaluations on days 3, 6, 15 and 30. Patients from the CAD group had evaluations on days 1 and 30 of the study, and the healthy volunteers were evaluated on day 1. Pulmonary function was evaluated by measuring forced vital capacity (FVC), maximum expiratory pressure (MEP) and Maximum inspiratory pressure (MIP).</p> <p>Results</p> <p>After CABG, there was a significant decrease in pulmonary function (p < 0.05), which was the worst on postoperative day 3 and returned to the preoperative baseline on postoperative day 30.</p> <p>Conclusion</p> <p>Pulmonary function decreased after CABG. Pulmonary function was the worst on postoperative day 3 and began to improve on postoperative day 15. Pulmonary function returned to the preoperative baseline on postoperative day 30.</p