Immunosuppressive treatment of rippling muscles in patients with myasthenia gravis.
ABSTRACT Rippling muscle disease is a rare autosomal dominant disorder that may occur sporadically. In this report two patients presenting with rippling muscles followed by myasthenia gravis are described. Our first patient developed rippling muscles about 1 month after infection with Yersinia enterocolitica. Two years later myasthenia gravis appeared. Our second patient had a 2-year history of asthma prior to the onset of rippling muscles which preceded the myasthenic symptoms by 4-8 weeks. Acetylcholine receptor and anti-skeletal muscle antibody titers were positive in both patients. In both patients the rippling phenomena worsened with pyridostigmine treatment but markedly improved after immunosuppression with azathioprine.
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ABSTRACT: Recent advances in understanding the molecular basis of human X-linked muscular dystrophies have come from the identification of dystrophin, a cytoskeletal protein associated with the surface membrane. Although there is little or virtually no dystrophin in affected individuals, it is not known how this causes muscle degeneration. One possibility is that the membrane of dystrophic muscle is weakened and becomes leaky to Ca2+. In muscle from mdx mice, an animal model of the human disease, intracellular Ca2+ is elevated and associated with a high rate of protein degradation. The possibility that a lack of dystrophin alters the resting permeability of skeletal muscle to Ca2+ prompted us to compare Ca2(+)-permeable ionic channels in muscle cells from normal and mdx mice. We now show that recordings of single-channel activity from mdx myotubes are dominated by the presence of Ca2(+)-permeable mechano-transducing ion channels. Like similar channels in normal skeletal muscle, they are rarely open at rest, but open when the membrane is stretched by applying suction to the electrode. Other channels in mdx myotubes, however, are often open for extended periods of time at rest and close when suction is applied to the electrode. The results show a novel type of mechano-transducing ion channel in mdx myotubes that could provide a pathway for Ca2+ to leak into the cell.Nature 05/1990; 344(6267):670-3. · 38.60 Impact Factor
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ABSTRACT: Mechanosensitive channels can be observed in most cell types during single-channel recording and have been implicated in many cellular processes. Potassium-selective single-channel currents, both stretch-activated and stretch-inactivated, can be observed in growth cones and cell bodies of Lymnaea stagnalis neurons. Equivalent macroscopic mechanosensitive currents could not, however, be elicited while applying various mechanical stimuli. This discrepancy suggests that single-channel mechanosensitivity is an artifact of patch recording.Science 04/1991; 251(4998):1246-9. · 31.03 Impact Factor
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ABSTRACT: Myotonia is a symptom, which occurs in a series of hereditary diseases, and it is also seen in less frequently occurring syndromes. A summary is given of conditions with myotonia. Five cases are reported from a family with a dominant hereditary disease presenting myotonia, muscular hypertrophy and increased muscle irritability as the only symptoms. In the most affected patient, some unusual rolling muscle contractions are seen. Apart from a moderate increase of creatin kinase, supplementary examinations are normal. The clinical picture resembles myotonia congenita Thomsen, but differs from this in significant respects. Other diagnostic possibilities are also considered. It is concluded that the clinical picture is different from all previously described conditions.Acta Neurologica Scandinavica 04/1975; 51(3):225-32. · 2.47 Impact Factor