Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tenascin-C (TN-C) is an extracellular matrix protein expressed during development in several tissues, but restricted to only a few areas in normal adult tissues. By immunizing mice with human fetal myoblasts we generated a monoclonal antibody to TN-C and mapped the epitope to the aminoterminal end containing EGF-like repeats. Using this antibody we detected by immunohistochemistry TN-C in the epimysium and perimysium of human fetal muscles, as well as in nonfibrillar deposits in myoblast cultures. In situ hybridization did not reveal any signal within human fetal muscle groups, suggesting that non-muscle cells synthesize the majority of the tenascin that localizes in and around human fetal muscle. Immunohistochemical analysis of muscle biopsies from Duchenne/Becker muscular dystrophy and myositis patients revealed that TN-C is expressed in skeletal muscle. Although the patterns of TN-C immunoreactivity were quite different in the two disease entities, the endomysial TN-C reactivity in both DMD/BMD and in myositis invariably correlated with the presence of macrophages.
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PMID:Tenascin-C expression correlates with macrophage invasion in Duchenne muscular dystrophy and in myositis. 913 39

The pathogenesis of the inflammatory myopathies is still unclear, making their treatment largely empirical. Improved understanding of the molecular mechanisms of inflammatory muscle injury may, however, lead to the development of more specific immunotherapies. To elucidate a possible pathogenic contribution of calcium-binding proteins such as the annexins, we immunohistochemically investigated muscle biopsy specimens from patients with dermatomyositis (10 cases), polymyositis (9 cases), and inclusion-body myositis (4 cases), compared to control cases comprising sarcoid myopathy (3 cases), Duchenne muscular dystrophy (DMD; 4 cases), and normal muscle (3 cases). We found expression of annexins A1, A2, A4, and A6 in the vascular endothelium of all cases. Myofibers expressed annexins A5, A6, and A7 diffusely and weakly in the cytosol, whereas annexins A5 and A7 were also particularly localized to the sarcolemma. In the inflammatory myopathies, in areas of myonecrosis in DMD, and in granulomatous lesions of sarcoid myopathy, reactivity of annexins A1, A2, A4, A5, and A6 was observed in macrophages and T-lymphocytes. Whereas the latter annexins appear to be nonspecific indicators of activation, annexin A1 upregulation may represent endogenous anti-inflammatory mechanisms that merit further investigation.
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PMID:Annexin expression in inflammatory myopathies. 1522 85

Muscle disorders are characterized by differential involvement of various muscle groups. Among these, weakness predominantly affecting finger flexors is an uncommon pattern, most frequently found in sporadic inclusion-body myositis. This finding is particularly significant when the full range of histopathological findings of inclusion-body myositis is not found on muscle biopsy. Prominent finger flexor weakness, however, is also observed in other myopathies. It occurs commonly in myotonic dystrophy types 1 and 2. In addition, individual reports and small case series have documented finger flexor weakness in sarcoid and amyloid myopathy, and in inherited myopathies caused by ACTA1, CRYAB, DMD, DYSF, FLNC, GAA, GNE, HNRNPDL, LAMA2, MYH7, and VCP mutations. Therefore, the finding of finger flexor weakness requires consideration of clinical, myopathological, genetic, electrodiagnostic, and sometimes muscle imaging findings to establish a diagnosis.
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PMID:Myopathies with finger flexor weakness: Not only inclusion-body myositis. 3247 19