Electron microscopic study of the muscle changes in diabetic amyotrophy

The syndrome of diabetic amyotrophy

Changes in the electromyograms and motor nerve conduction velocities in 12 patients with diabetic amyotrophy suggested mild distal and moderate proximal neuropathy in the lower limbs. Histological and histochemical findings in the vastus medialis muscles were consistent with denervation. Electron microscopical examination of the vastus medialis muscles in 6 patients revealed myofibrillar degeneration. One patient had abnormal mitochondria and tubular aggregates. The basement membranes of the intramuscular capillaries were thickened in all but 1 patient. Histochemical staining of the myoneural junctions showed changes consistent with degeneration and regeneration. We conclude that diabetic amyotrophy is a distinct clinical entity and is secondary to metabolic derangement rather than diabetic microangiopathy.

Histochemical and ultrastructural changes in senile human skeletal muscle

Eighty biopsy specimens of muscles from 79 elderly patients (chiefly in the 60-90 age group) were examined by histochemical and electron microscopic methods. Neuropathic change and type-II fiber atrophy of various grades were prominent findings in the muscles from patients of advanced age. Nemaline rod formation, "ragged red" change and an increase of sarcolemmal nuclei were also common. Several electron microscopic features of the muscle fiber corresponded to those reported for various neuromuscular diseases. Various factors associated with the aging process apparently act on the motor neurons and cause the neuropathic and myopathic changes seen in the muscles of the aged.

[Mitochondrial changes of the skeletal muscle in the peroneal muscular atrophy (Charcot-Marie-Tooth disease). Histological and electron microscopic studies (author's transl)]

This report deals with two sisters (38 and 44 years old) suffering from Charcot-Marie-Tooth disease. Muscle biopsies were taken from the deltoid and the rectus femoris. In one of the cases a sural nerve biopsy was also made. Light microscopy showed only slight myopathic changes. The histochemical reactions disclosed an increase in lipid deposition and in NADH-TR activity of type 1 fibres. Electron microscopy showed abnormal mitochondrial aggregates, which were surrounded inconstantly by glycogen deposits, especially in subsarcolemmal space. Many of the atypical mitochondria showed paracristalline inclusions within the cristae. The significance of these findings is discussed and compared with similar reports in the literature.