[Animal experiment and biopsy studies on the cause, manifestations and diagnostic relevance of perifascicular muscle fiber atrophy].

On the basis of previous (n = 23) and current muscle biopsies (n = 25) as well as five animal-experimental investigations, the paper deals with the cause and the manifestation of perifascicular muscle-fiber atrophy. A deteriorated trophic situation of the subfascial or marginal muscle fibers in patients suffering from immunocomplex vasculopathies in connection with a reduced supply of blood to the muscles is seen as the cause of the areactive weight loss (atrophy). This is accompanied by a considerably reduced capillary supply of blood to the muscle fibers. Even in normal conditions, the portion of collateral vessels and capillaries is lower in the subfascial region than in the center of the fascicle. When the blood supply is disturbed, the marginal fibers are in a trophic situation worse than that of the central muscle fibers. They become atrophied. In responsive patients, the muscle fibers regenerate and recapillarize during the convalescence period. This can be shown histochemically by means of the alkaline phosphatase reaction. The extent of perifascicular musclefiber atrophy can be fixed in quantitative terms by the method of Baumli and Mumenthaler. Where a second biopsy is indicated, results can be obtained regarding the changes in the perifascicular atrophy as a consequence of the therapy provided.