Human Skeletal Muscle Fibers in Normal and Pathological States; Freeze-etch Replica Observations

Distinct differences are seen regarding size distribution of apertures of caveolae and T-system tubules on PF- and EF-faces of the sarcolemma of normal human skeletal muscle fibers. As for intramembranous particles, a greater number is found on the PF-face. The size distribution of apertures on PF-faces in cases of certain neuromnscular diseases is as follows: dystrophy (Duchenne and congenital) shows a pattern similar to that of control, while In dermatomyositis and Werdnig-Hoffmann disease, apertures have diameters of various sizes. Differences In the number of particles on PF-faces in these disorders are also evident. In cases of muscular dystrophy there is a distinct increase in the number of particles, while in case of dermatomyositis, the number of particles is about the same as in the control. In Werdnlg-Hoffmann disease, there are increases in particles in some parts and decreases in others.