[An electrophoretic study of the muscle proteins in nemaline myopathy: a new method using type-defined freeze-dried sections].

The characteristic features observed in the muscle fibers of nemaline myopathy are the presence of rods mainly in type I fibers, and the predominance and atrophy of type I fibers. In order to detect the abnormal proteins in the rods and clarify whether type I or II fibers have abnormal structural protein, we examined proteins in the muscles of patients with nemaline myopathy by one and two-dimensional gel electrophoresis (2-D). These freshly frozen muscles were cut to 20 microns thick and freeze-dried. Pieces were chosen and teased under a dissecting microscope with reference to the stained specimens of the same part, and electrophoresed. At first, we examined the proteins of the type I and II fibers in normal and type grouping fibers of patients with motor neuron disease by SDS gel electrophoresis and found no abnormality of the protein pattern in this disease. Then we examined each of the following fibers of the nemaline muscle; type I fibers with many rods and type II fibers with no rods. Each of the electrophoresed gel patterns of the nemaline muscle was compared with those of grouping type I and II fibers. The SDS gel electrophoresis showed and increase of the intensity of 55 K band in nemaline myopathy, especially in type I fibers with rods, which was thought as desmin. In 2-D, the pattern of type I fibers with rods were identical to that of the grouping type I fibers except the 55 K spot which showed a slow form of tropomyosin alpha-subunit (TM-alpha), troponin-C (TN-C) and myosin light chains (LC) although both contained small amounts of fast form LC2 and LC3.(ABSTRACT TRUNCATED AT 250 WORDS)