抄録
The biopsy materials of the sural nerve and the quadriceps femoris muscle obtained from 37 diabetic patients were studied by light and electron microscopy. The ages at the onset were below 30 years in 13 cases.
Sural nerve studies
1) Degeneration or disintegration of the myelin sheaths was observed in all cases of adult onset and 83% of cases of juvenile onset diabetes.
2) Cell inclusions of lipid were noted in 13 of 18 adult cases and 3 of 5 juvenile cases in the cytoplasm of Schwann cells of the myelinated nerve fibers.
3) Degeneration of the myelin sheaths was seen more frequently in adult cases than in juvenile cases. Therefore such changes might be related with aging process to some extent.
4) In one case of juvenile type, degeneration of the axon without accompanying changes of the myelin sheaths was observed. This finding suggested that the changes of the axon preceded that of the myelin sheaths in some occasions while most of the diabetic neuropathy started from Schwann cell changes with subsequent myelin sheath degeneration.
Muscle studies
1) Light microscopic observations of the muscle revealed mixture of both neurogenic and myogenic changes.
2) Light microscopically, focal degeneration seemed to be one of the features. Electron microscopically intact muscle fibers and completely degenerated ones were seen neighboringly as frequent observations.
3) Abnormally increased lipopigment between the myofibrils was another frequent finding.
4) Thickning of the basement membranes of the capillaries was remarkable and related with the diabetic changes of the ocular fundus.
5) Accumulations of the glycogen granules were often observed between myofibrils.
6) Crystalline inclusion bodies within the mitochondria, which had been reported in some types of myopathies for the past several years, were observed in one case and this was the first observation as far as diabetes mellitus was concerned.
