title: Striated muscle in four categories of leprosy. II. Fine structural changes.
abstract: Fine structural changes are described in 21 muscle biopsy specimens from patients with early and established tuberculoid or treated and untreated lepromatous leprosy. The predominant light microscopic finding on paraffin sections of atrophy of the muscle fiber was confirmed in semithin araldite sections, which also revealed considerable degenerative changes in a few or more fibers. These were more clearly seen in ultrathin sections, especially in the lepromatous muscle specimens. The degeneration was in the form of severe loss or disorganization of the myofibrillar elements and in the most affected muscle fiber, a loss of all sarcoplasmic constituents, with occasional accumulation of lipofuscin in lysosome-like bodies. Only 3 of the lepromatous specimens showed 1 and 2 bacilli each, only 1 being within a muscle fiber. There were also mural changes in the small intramuscular blood vessels with proliferation of their basement membrane and pericytes. The mean serum IgG level in lepromatous patients was significantly elevated. This, together with the vascular change, might perhaps be responsible for the degenerative change in the muscle fiber despite a paucity of M. leprae in the muscle.
mesh_terms: D001284:Atrophy; D001808:Blood Vessels / Q000648:ultrastructure; D003402:Creatine Kinase / Q000097:blood; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007918:Leprosy / Q000097:blood / Q000145:classification / Q000473:pathology*; D008854:Microscopy, Electron; D009132:Muscles / Q000098:blood supply / Q000382:microbiology / Q000648:ultrastructure*; D009166:Mycobacterium leprae / Q000302:isolation & purification; D009210:Myofibrils / Q000648:ultrastructure
chemical_list: D007074:Immunoglobulin G; D003402:Creatine Kinase