Key result
Myopathic muscles from patients with Duchenne dystrophy, myotonic dystrophy, or polymyositis exhibited an increased proportion of intermediate fibers containing fast and slow myosin or molecular hybrids.
Observational
Myopathic muscles show an increased proportion of intermediate fibers with mixed or hybrid myosin isoforms, suggesting changes in the equilibrium between fast and slow motor units.
May reflect motor unit remodeling in myopathies; leaves open the functional impact of hybrid fibers on progression or therapy.
We evaluated the isoform composition of heavy and light chains of myosin in single muscle fibers from patients with Duchenne dystrophy, myotonic dystrophy, or polymyositis. In all myopathic muscles, there was an increase in the proportion of intermediate fibers which, by analysis of myosin isoforms, fell into two subpopulations, one that contained both fast and slow myosin and another that contained myosin molecular hybrids. The increased proportion of intermediate (or transitional) fibers suggests changes in the equilibrium between fast and slow motor units. These changes could result from regeneration and subsequent maturation of fibers or from direct transformation of mature fibers of one type into the opposite.
No takes yet. Share an insight, caveat, or question.
Salviati et al. (1986) conducted an observational in Duchenne dystrophy, myotonic dystrophy, or polymyositis. Myopathy (Duchenne dystrophy, myotonic dystrophy, or polymyositis) was evaluated on Isoform composition of heavy and light chains of myosin in single muscle fibers. Myopathic muscles from patients with Duchenne dystrophy, myotonic dystrophy, or polymyositis exhibited an increased proportion of intermediate fibers containing fast and slow myosin or molecular hybrids.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: