FIBRILLATIONS IN REGENERATING MUSCLE IN DYSTROPHIC MYOPATHIES

In the presented study we attempted to demonstrate a correlation betwe en muscle regeneration and fibrillations in electromyography in dystro phic myopathies. Especially in Emery-Dreifuss muscular dystrophy there is much abnormal spontaneous activity, and NCAM (neural cell adhesion molecule) and cytoskeletal protein vimentin expressing myocytes are p redominantly seen. Therefore, definitely regenerating fibers are ident ified apart from only a few remnants of previous necrosis. Moreover, i n the other biopsies of dystrophic myopathies there are also scattered and clustered NCAM and vimentin expressing regenerating myofibers. He re, regressive fiber changes, like necrosis, are more prominent. Furth ermore, most regenerating fibers show pseudo-cholinesterase activity i ndicating innervation. Interestingly, motor end-plate changes in regen eration and in disuse atrophy are very similar. They predominantly con sist of terminal sprouting and pseudo-cholinesterase spread. However, in disuse atrophy there is no abnormal spontaneous spread in electromy ography. Therefore, in regenerating muscle not innervation, but regene ration itself is likely to be the cause of fibrillations. In conclusio n, a correlation is evident between regenerating muscle and fibrillati ons in electromyography.