Effect of sodium bicarbonate on muscle metabolism during intense endurance cycling.

Introduction: Sodium bicarbonate (NaHCO3) ingestion has been shown to increase both muscle glycogenolysis and glycolysis during brief submaximal exercise. These changes may be detrimental to performance during more prolonged, exhaustive exercise. This study examined the effect of NaHCO3 ingestion on muscle metabolism and performance during intense endurance exercise of approximately 60 min in seven endurance-trained men.

Similar COL1A1 expression in fibroblasts from some patients with clinical otosclerosis and those with type I osteogenesis imperfecta.

Because of the clinical and histopathologic similarities between otosclerosis and type I osteogenesis imperfecta, we examined COL1A1 messenger RNA (mRNA) expression in cultured fibroblasts from patients with clinical otosclerosis to determine whether abnormalities of expression of COL1A1 were present, as has been reported in type I osteogenesis imperfecta. Type I osteogenesis imperfecta has been found to result from mutations in the COL1A1 gene that result in null expression of the mutant allele. Patients with clinical otosclerosis were genotyped for the presence of an expressed 4 base-pair insertion polymorphism in the 3' region of the COL1A1 gene.

Effects of fatigue and training on sarcoplasmic reticulum Ca(2+) regulation in human skeletal muscle.

Little is known about fatigue and training effects on sarcoplasmic reticulum (SR) function in human muscle, and we therefore investigated this in eight untrained controls (UT), eight endurance-trained (ET), and eight resistance-trained athletes (RT). Muscle biopsies (vastus lateralis) taken at rest and after 50 maximal quadriceps contractions (180 degrees/s, 0.5 Hz) were analyzed for fiber composition, metabolites and maximal SR Ca(2+) release, Ca(2+) uptake, and Ca(2+)-ATPase activity.