Learn More
1. Comparisons were made in vitro at 25 degrees C among soleus and extensor digitorum longus (EDL) muscles from young (2-3 months), adult (9-10 months), and aged (26-27 months) male mice. We tested the hypotheses that, compared with soleus and EDL muscles of young and adult mice, those from aged mice develop decreased maximum tetanic force (P0, mN) and(More)
Limb-girdle muscular dystrophy type 2D (LGMD 2D) is an autosomal recessive disorder caused by mutations in the alpha-sarcoglycan gene. To determine how alpha-sarcoglycan deficiency leads to muscle fiber degeneration, we generated and analyzed alpha-sarcoglycan- deficient mice. Sgca-null mice developed progressive muscular dystrophy and, in contrast to other(More)
Contraction-induced injury results in the degeneration and regeneration of muscle fibers. Of the three types of contractions--shortening (concentric), isometric, and lengthening (eccentric)--injury is most likely to occur and the severity of the injury is greatest during lengthening contractions. The magnitude of the injury to muscle fibers may be assessed(More)
We describe a novel phenotype in mice lacking the major antioxidant enzyme, CuZn-superoxide dismutase (Sod1(-/-) mice), namely a dramatic acceleration of age-related loss of skeletal muscle mass. Sod1(-/-) mice are 17 to 20% smaller and have a significantly lower muscle mass than wild-type mice as early as 3 to 4 months of age. Muscle mass in the Sod1(-/-)(More)
We tested the hypothesis that lengthening contractions result in greater injury to skeletal muscle fibers than isometric or shortening contractions. Mice were anesthetized with pentobarbital sodium and secured to a platform maintained at 37 degrees C. The distal tendon of the extensor digitorum longus muscle was attached to a servomotor. A protocol(More)
As compared with age-matched controls, extensor digitorum longus (EDL) muscles autografted in young rats regenerated significantly greater mass (1.8 times) and developed greater maximum contractile force (2.6 times) than EDL muscles autografted in old rats. A cross-age transplantation study showed that the mass and maximum force of old muscles grafted into(More)
Dystrophin is a multidomain protein that links the actin cytoskeleton to laminin in the extracellular matrix through the dystrophin associated protein (DAP) complex. The COOH-terminal domain of dystrophin binds to two components of the DAP complex, syntrophin and dystrobrevin. To understand the role of syntrophin and dystrobrevin, we previously generated a(More)
Ageing is associated with skeletal muscle atrophy, a deficit in force generation, an increased susceptibility to contraction-induced injury, and a permanent force deficit following severe injury. Muscles of young mice adapt rapidly following exercise by an increase in the production of heat shock proteins (HSPs), whereas muscles of old mice show a severely(More)
1. Mdx mice were used as a model for Duchenne muscular dystrophy; both lack dystrophin. It was hypothesized that the mdx condition would have a marked effect on the ability of diaphragm muscle from mdx mice to do active net work and generate power. This hypothesis was tested using the work-loop technique. 2. Specific twitch force, specific tetanic force and(More)
Our purpose was to determine the effect of temperature on the fatigability of isolated soleus and extensor digitorum longus (EDL) muscles from rats during repeated isometric contractions. Muscles (70-90 mg) were studied at 20-40 degrees C in vitro. Fatigability was defined with respect to both the time and number of stimuli required to reach 50% of the(More)