Some observations on muscle biopsies before and after denervation. Histological and biochemical changes in human extensor hallucis and digitorum brevis muscles two weeks after denervation.

In 7 patients biopsies of the extensor hallucis or digitorum brevis muscles were obtained before and 2 weeks after surgical denervation. Ultrastructural morphology showed convincing phenomena of denervation, but not of incipient regeneration. No increase (or decrease) of single or 'twin' myonuclei could be demonstrated in light microscopic examination of semithin sections. Histochemical examination did not show significant changes, but revealed type grouping in all biopsies, presumably due to previous denervation-reinnervation processes. Biochemical studies revealed decreased cytochrome c oxidase activities in the biopsies after denervation. Clinical and electromyographic examinations at later dates showed that the muscle transplantations had been successful.