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M K Sargeant

Publications and source records attributed to M K Sargeant.

5 recordsLinked to original sources
PubMed1978

The significance of ragged-red fibres in neuromuscular disease.

The pathological significance of ragged-red fibres is uncertain. We have studied ragged-red fibres in the muscle biopsies of 3 adults; one with polymyositis and two with progressive external ophthalmoplegia. All the ragged-red fibres were Type 1 fibres. In two patients the mean diameter of the ragged-red fibres was significantly smaller than the unaffected Type 1 fibres. Some of these fibres showed features of regeneration, and others of degeneration. In the patient with polymyositis the mitochondria were proliferated and contained osmiophilic dense bodies; in the other two patients paracrystalline mitochondrial inclusions were prominent. These findings suggest that ragged-red fibres do not represent a single pathological process.

Adult↗
PubMed1977

Neostigmine-induced end-plate proliferation in the rat. A study using supra-vital methylene blue.

The supra-vital methylene blue technique was used to study motor end-plate morphology in 21 BD-1X rats, treated for 7 to 16 weeks with oral neostigmine bromide, and in five control animals. Motor endings of treated animals showed preterminal, terminal, and ultraterminal sprouting and an increase in mean end-plate length (p less than 0.001). These changes were most prominent after 14 weeks of treatment. After 16 weeks of therapy, mean end-plate length decreased and the proliferative abnormality became less evident. The adverse effect of neostigmine on motor end-plates may have clinical relevance in the management of myasthenia gravis and may be partly responsible for the end-plate abnormalities previously reported in this disease.

Administration, Oral↗
PubMedDate not supplied

Pathogenesis of longitudinal splitting of muscle fibres in neurogenic disorders and in polymyositis.

Longitudinal splitting of muscle fibres has been studied in the biopsies of eighteen patients with neurogenic disorders, and of twenty with polymyositis. In neurogenic disorders splitting predominantly affects hypertrophied fibres, and is probably due to mechanical overload induced by normal loads imposed on a weakened muscle. A similar phenomenon occurs in hypertrophied fibres in chronic polymyositis. However, in acute, or active polymyositis an appearance resembling fibre splitting can result from sequestration of necrotic segments within a fibre and also from regeneration occurring within intact sarcolemmal tubes after segmental sub-endomysial necrosis. These different processes, which can be distinguished by light and ultrastructural criteria, are important compensatory factors in neuromuscular disorders.

Adult↗