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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cystatin C (CC), an endogenous cysteine protease inhibitor, is accumulated within amyloid-beta (A beta) amyloid deposits in Alzheimer's disease (AD) brain and was proposed to play a role in the AD pathogenesis. Because the chemo-morphologic muscle phenotype of sporadic inclusion-body myositis (s-IBM) has several similarities with the phenotype of AD brain, including abnormal accumulation of A beta deposits, we studied expression and localization of CC in muscle biopsies of 10 s-IBM, and 16 disease- and five normal-control muscle biopsies. Physical interaction of CC with amyloid-beta precursor protein (A beta PP) was studied by a combined immunoprecipitation/immunoblotting technique in the s-IBM muscle biopsies and in A beta PP-overexpressing cultured human muscle fibers. In all s-IBM muscle biopsies, CC-immunoreactivity either colocalized with, or was adjacent to, the A beta-immunoreactive inclusions in 80-90% of the vacuolated muscle fibers, mostly in non-vacuolated regions of their cytoplasm. Ultrastructurally, CC immunoreactivity-colocalized with A beta on 6-10 nm amyloid-like fibrils and floccular material. By immunoblotting, CC expression was strongly increased in IBM muscle as compared to the controls. By immunoprecipitation/immunoblotting experiments, CC coimmunoprecipitated with A beta PP, both in s-IBM muscle and in A beta PP-overexpressing cultured normal human muscle fibers. Our studies (i) demonstrate for the first time that CC physically associates with A beta PP, and (ii) suggest that CC may play a novel role in the s-IBM pathogenesis, possibly by influencing A beta PP processing and A beta deposition.
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PMID:Cystatin C colocalizes with amyloid-beta and coimmunoprecipitates with amyloid-beta precursor protein in sporadic inclusion-body myositis muscles. 1278 72

The idiopathic myositis, dermatomyositis, polymyositis and inclusion body myositis are recognized by their clinical and laboratory presentation, and by morphological changes in the muscle biopsy. A rapid diagnostic process is important, in order to start early treatment, which will be more effective and to direct further investigations and management. In the presence of dermatomyositis a precise investigation of neoplasia is important because they are often associated, which is not the case with inclusion body myositis. Symptoms in dermatomyositis and polymyositis respond sometimes quite well to immunomodulatory therapy but not in inclusion myositis. Controlled muscle training may sometimes slow progression in inclusion myositis.
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PMID:[Idiopathic myositis]. 1295 34

The inflammatory myopathies include dermatomyositis (DM), polymyositis (PM), and sporadic inclusion-body myositis (s-IBM). In DM, the main immune effector response appears to be humoral and directed against the microvasculature, whereas in both PM and s-IBM, cytotoxic CD8+ T cells and macrophages invade and eventually destroy nonnecrotic muscle fibers expressing major histocompatibility complex class I. The need for more specific and safer therapies in inflammatory myopathies has prompted researchers to better decipher the molecular events associated with inflammation and muscle fiber loss in these diseases. The complex specific migration of leukocyte subsets to target tissues requires a coordinated series of events, namely activation of leukocytes, adhesion to the vascular endothelium, and migration. Cell adhesion molecules (CAM) and chemokines play a major role in this multistep process. In addition, cytokines by stimulating CAM expression and orchestrating T-cell differentiation also influence the immune response. This review focuses on recent advances in defining the molecular events involved in leukocyte trafficking in inflammatory myopathies. Specific topics include a concise summary of clinical features, pathological findings and immunopathology observed in inflammatory myopathies, background information about cytokines, chemokines and cell adhesion molecules, and the expression of these molecules in inflammatory myopathies.
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PMID:Cytokines, chemokines, and cell adhesion molecules in inflammatory myopathies. 1463 80

Inflammatory myopathies can be subdivided into two main groups: infectious (bacterial, viral or other) myositis and immunogenic myositis. According to their frequency there are four main groups of diseases: dermatomyositis (DM), overlap syndromes, inclusion body myositis (IBM), idiopathic polymyositis (PM). Muscle weakness and atrophy are the prominent clinical symptoms of all immunogenic inflammatory myopathies. Muscle pain is not so common and occurs more frequently in acute forms than in chronic cases. Primary chronic forms of polymyositis and inclusion body myositis are mostly painless. Diagnosis starts with electromyography and laboratory investigations (especially CK). Myositis associated antibodies are mostly associated with acute forms. Radiological methods, especially MRI, are important in chronic cases. Definite diagnosis has to be done by muscle biopsy. Immunohistological (especially in DM and PM) and ultrastructural (especially in IBM) techniques are necessary in some cases. Concerning therapy of DM and PM, corticosteroids in combination with immunosuppressive drugs are effective in most cases. Intravenous immunoglobulins are needed only in selected cases (severe forms), side effects of therapy or resistance to conventional therapy. In IBM, it is the only therapeutic possibility, especially in young patients with rapid progression of the disease.
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PMID:[Importance of inflammatory myopathies in practice]. 1464 16

Oxidative stress has been implicated in the pathogenesis of several muscle diseases. Semicarbazide-sensitive amine oxidase (SSAO) metabolizes oxidative deamination of primary aromatic and aliphatic amines. In the oxidative reactions, amine substrates are converted into the aldehyde, followed by the production of ammonia and H(2)O(2). Although normal levels in muscle are very low, SSAO is expressed in almost all mammalian tissues. In this study, we examined the possible implication of SSAO as an additional source of oxidative stress in the pathogenesis of muscle disorders. The expression of SSAO was examined immunohistochemically in muscle biopsy specimens from patients with inclusion-body myositis (IBM; n = 5), desmin-related myopathy (DRM; n = 3), dermatomyositis (n = 3), granulomatous (sarcoid) myopathy (n = 2), muscle denervation-reinnervation (n = 3), and rhabdomyolysis (n = 2), as well as from control subjects (n = 3). Strong SSAO immunoreactivity was present in vacuolated and nonvacuolated fibers in IBM, in abnormal fibers in DRM, and in degenerating and regenerating fibers in dermatomyositis and rhabdomyolysis. In addition, SSAO overexpression was observed in muscle fibers adjacent to granulomas in sarcoid myopathy. These results suggest that SSAO is a source of oxidative stress in diseased human skeletal muscle and that it contributes to oxidative stress-induced damage in various inflammatory and other myopathies. Alternatively, the expression of SSAO in muscle fibers may be a consequence of muscle fiber injury.
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PMID:Overexpression of semicarbazide-sensitive amine oxidase in human myopathies. 1475 92

The paediatric idiopathic inflammatory myopathies (IIMs) are a group of rare but serious systemic autoimmune conditions of childhood. The most common of the paediatric IIMs is juvenile dermatomyositis (JDM), while polymyositis and inclusion body myositis are rare in children. JDM has a significantly different spectrum of disease from adult dermatomyositis. Juvenile myositis can also occur as part of other systemic autoimmune diseases such as scleroderma and systemic lupus erythematosus. There has recently been significant progress towards the development and validation of tools to measure disease activity and damage in the paediatric IIMs. In addition, several new therapeutic avenues have been used to treat JDM. This review will discuss developments in the diagnostic criteria for JDM, the clinical types and course of these conditions, recent progress in disease assessment, treatment options and new developments in research into the pathogenesis of paediatric IIM.
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PMID:Paediatric idiopathic inflammatory muscle disease. 1515 45

Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) infection can lead to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), concomitantly with or without other inflammatory disorders such as myositis. These pathologies are considered immune-mediated diseases, and it is assumed that migration within tissues of both HTLV-1-infected CD4(+) T cells and anti-HTLV-1 cytotoxic T cells represents a pivotal event. However, although HTLV-1-infected T cells were found in inflamed lesions, the antigenic specificity of coinfiltrated CD8(+) T cells remains to be determined. In this study, we performed both ex vivo and in situ analyses using muscle biopsies obtained from an HTLV-1-infected patient with HAM/TSP and sporadic inclusion body myositis. We found that both HTLV-1-infected CD4(+) T cells and CD8(+) T cells directed to the dominant Tax antigen can be amplified from muscle cell cultures. Moreover, we were able to detect in two successive muscle biopsies both tax mRNA-positive mononuclear cells and T cells recognized by the Tax11-19/HLA-A*02 tetramer and positive for perforin. These findings provide the first direct demonstration that anti-Tax cytotoxic T cells are chronically recruited within inflamed tissues of an HTLV-1 infected patient, which validates the cytotoxic immune reaction model for the pathogenesis of HTLV-1-associated inflammatory disease.
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PMID:Direct evidence for a chronic CD8+-T-cell-mediated immune reaction to tax within the muscle of a human T-cell leukemia/lymphoma virus type 1-infected patient with sporadic inclusion body myositis. 1536 98

We report the first case of inclusion body myositis (IBM) which occurred after interferon-alpha treatment for chronic hepatitis C. A 63-year-old man contracted hepatitis C virus (HCV) and human T cell leukemia virus type 1 (HTLV-1) from a blood transfusion at age of 18. At age 57, he was treated with interferon-alpha (IFN alpha) for chronic hepatitis C. A month later, he developed muscle weakness in the proximal part of his lower extremities. IBM was diagnosed after a muscle biopsy at age 62. Steroid therapy improved his muscle power. One year later, worsening of his hepatic condition required re-administration of IFN alpha after gradual decrease and discontinuation of prednisolone. However, several days later, he rapidly became weaker and required a cane to walk. Elevated serum creatine kinase (2,199IU/L) and abnormal intensity in his MRI of thigh were demonstrated. The second muscle biopsy, performed after obtaining the informed consent from our patient, confirmed relapse of IBM. His symptoms improved again after discontinuation of IFN alpha and re-induction of prednisolone. Although a few cases each of IBM associated with HCV or HTLV-1 have been reported, the pathogenesis of virus-associated inflammatory myositis has not been clearly understood. Moreover, there has been no description on IBM associated with IFN alpha treatment, though several cases of polymyositis have been reported. Our case suggests that infection of HCV and HTLV-1 may be immunologically involved in the development of IBM and that IFN alpha can be directly related to onset and relapse of IBM.
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PMID:[Inclusion body myositis after interferon-alpha treatment in a patient with HCV and HTLV-1 infection]. 1551 4

COMMON ELEMENTS: Primary inflammatory myopathies consist of dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). They have certain characteristics in common: progressive muscle weakness and mononuclear inflammatory infiltrates in the muscle. DIFFERENT MECHANISMS: They may be distinguished by their histological features which also reflect their different underlying pathogeneses. The mechanism of DM would be complement-mediated microangiopathy, the inflammatory infiltrate of which would be secondary to ischemic phenomena, whereas in PM the muscle fibres are damaged by cytotoxic CD8 T lymphocytes. The factors triggering-off these two forms of myositis remain unknown. IBM may be a degenerative disease with accumulation of a variety of proteins within the fibres. The inflammatory infiltrate, which is similar to that seen in PM, may be a reaction to accumulated proteins.
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PMID:[Pathogenesis of primary inflammatory myopathies]. 1561 79

Polymyositis, dermatopolymyositis, and inclusion body myositis imply chronic inflammation of skeletal muscles. Pulmonary complications include aspiration pneumonia, interstitial pneumonitis, or respiratory muscle myositis. This study aims at better describing their impact on respiratory muscle. Twenty-three consecutive patients (12 PM, 5 DM, 6 IBM) were studied (static inspiratory and expiratory pressures; diaphragm function in terms of the mouth and transdiaphragmatic pressure responses to bilateral phrenic stimulation). Pulmonary parenchymatous abnormalities were mild (6 cases) or absent. The mouth pressure produced by phrenic stimulation was 6.83+/-3.01 cm H2O, with 18 patients (78%) diagnosed with diaphragm weakness (<10 cm H2O) and lower values in DM (4.35+/-1.48 cm H2O) than in IBM and in PM (P<0.05). Diaphragm weakness is frequent and probably overlooked in inflammatory myopathies. Further studies are needed to delineate the clinical relevance of these results.
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PMID:Diaphragmatic dysfunction in patients with idiopathic inflammatory myopathies. 1563 18


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