glycogen and Myasthenia-Gravis

In 4 patients with clinical signs of dermatomyositis, confirmed by electromyography and muscle biopsy, a form of muscle fatigue was detected which was expressed clinically by predominantly proximal motor deficit, with phonation and deglutition disturbances, slightly influenced by prostigmine. In all patients, stimulation of the ulnar nerve at 3--10 Hz induced a decrement of muscle-evoked potentials in abductor digiti minimi and at 15--50 Hz an increment at the end of the trains (1.2 sec in duration) of repetitive stimulation (preceded in two cases by a decrement in the response to the fifth stimulus in the train). Stimulation at 30 Hz for 10 sec resulted in a transient facilitation, followed (at 3 Hz stimulation) by postactivation exhaustion which disappeared after 5--15 min. The post-tetanic facilitation, the incremental response and the myasthenic symptoms reverted to normal under treatment with corticosteroids, an immunosuppressor agent and guanidine hydrochloride. A mixed, pre- and postsynaptic mechanism is presumed to underlie the muscle fatigue in our patients. Electron microscopy of muscle biopsies disclosed zones of necrosis and, in incipient stages, large agglomerations of glycogen that had disorganized the structure of myofibrils. The end-plates in the biopsies were larger than normal and the cholinesterase reaction was hyperactive. Serum immunoelectrophoretic and electrophoretic data--increase of IgG and IgM, decrease of IgA and hypergammaglobulinaemia -- point to a possible autoimmune mechanism of the neuromuscular disorders in our patients.

Topics: Adolescent; Adult; Biopsy; Dermatomyositis; Electromyography; Evoked Potentials; Fatigue; Female; Glycogen; Guanidines; Humans; Male; Middle Aged; Muscle Contraction; Muscles; Myasthenia Gravis; Neostigmine; Prednisone; Synaptic Transmission; Ulnar Nerve

The ultrastructure of an epithelio-reticular cell thymoma associated with myasthenia gravis is described. The neoplastic cells of an epithelio-reticular nature were dominant in the neoplasm, being closely associated with lymphocytes and scattered non-neoplastic macrophages. The thymic epithelio-reticular cell showed abundant glycogen and some lipid droplets inside the cytoplasm, which was vacuolated and had many elongated processes attached to desmosomes and a very prominent nucleolus. The appearance was similar to that of the immature embryonic epithelial cell of the thymus seen in mammals. Very close contacts existed between the thymic lymphocytes and the epithelio-reticular cells, the appearance being suggestive of the phenomenon of "emperipolesis." Cell death occurred secondarily through nuclear pyknosis and chromatolysis. Lymphocytic debris appeared inside the epithelio-reticular cells and, to some extent, in the cytoplasm of the mesenchymal marcrophages not directly involved in the phenomenon of "emperipolesis."

Topics: Cell Nucleolus; Cytoplasmic Granules; Desmosomes; Glycogen; Humans; Lipids; Lymphocytes; Macrophages; Male; Microscopy, Electron; Middle Aged; Myasthenia Gravis; Thymoma; Thymus Neoplasms

Topics: Glycogen; Humans; Microscopy, Electron; Mitochondria; Myasthenia Gravis; Oculomotor Muscles; Ribosomes

Topics: Carcinoma, Squamous Cell; Glycogen; Glycolipids; Glycoproteins; Histocytochemistry; Humans; Methods; Muscular Diseases; Myasthenia Gravis; Organ Size; Oxidoreductases; Radiation Effects; RNA; Thymoma; Thymus Gland; Thymus Hyperplasia; Thymus Neoplasms

Topics: Adolescent; Adult; Aged; Child; Dermatomyositis; Glycogen; Glycolysis; Hexosephosphates; Humans; Lactates; Middle Aged; Motor Neurons; Muscles; Muscular Diseases; Muscular Dystrophies; Myasthenia Gravis; Myositis; Oculomotor Muscles; Phosphotransferases; Polyarteritis Nodosa