Chemical constituents of skeletal muscle from normal subjects and patients with rheumatic and non-rheumatic diseases.

Summary1. Gastrocnemius muscle samples from 13 normal individuals and 27 patients with arthritis and a number of miscellaneous diseases were analyzed for total protein, non-protein nitrogen, collagen, myosin, adenosinetriphosphatase and water. The chemical data were correlated with the results of histological examination of the muscle samples analyzed. 2. In muscle from 13 volunteers, myosin constituted 21.1 per cent of the total protein and 3.99 per cent of the wet weight. Significantly lower values were found, however, in all groups of patients, as well as in 3 normal volunteers in whom lymphocytic infiltrates were demonstrated microscopically. 3. The collagen fraction of the total protein did not depart significantly from the normal in any of the diseases studied, and did not change significantly in the presence of atrophy. The per cent of collagen based on wet weight, however, was significantly reduced in the group of 8 patients with rheumatoid arthritis and 3 patients with degenerative joint disease....