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

An electron microscopic investigation has been carried out on muscle bioptic samples from patients affected by rheumatoid arthritis (RA). This study was undertaken to seek further ultrastructural alterations affecting striated muscles in RA pathology. Bioptic samples were collected on a total of 30 surgical interventions of hip (10), knee (8), and foot (12). This yielded three muscle types: gluteus maximus, vastus lateralis, and extensor digitorum communis. Muscle samples from 12 patients with no RA stigmata, selected to match RA patients by age and gender, constituted the control group. Tissue samples were prepared both for conventional histochemical methods and according to conventional electron microscopic procedures, including morphometric analysis. Although to a different extent in each sample, in muscles from RA vs. controls the authors observed the simultaneous presence of discrete muscular alterations such as wider separation of myofibrils, myelin figures, dilated sarcotubular system, pleomorphic mitochondria, myofibril flaking, and lipofuscin deposition in the subsarcolemmal region. In addition to a progressive atrophy, the above findings are suggestive of rheumatoid myositis and lend further support to the still poorly documented presence of an idiopathic inflammatory myopathy and inclusion body myositis associated with RA.
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PMID:Muscle involvement in rheumatoid arthritis: an ultrastructural study. 1091 26

A case of a 38-year old man with a common variable immunodeficiency syndrome (CVID) is demonstrated who suffered at the same time from a histologically proven inclusion body myositis (IBM). The myositis did not resolve after institution of regular intravenous IgG infusions. This case demonstrates a very long lasting benign course of IBM. The occurrence with CVID may be a clinical hint for a viral pathogenesis of IBM. So far only two similar cases are reported in the literature.
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PMID:Common variable immunodeficiency (CVID) and inclusion body myositis (IBM). 1099 95

Recent studies have shown an up-regulation of the Fas/Fas ligand system in inflammatory myopathies. In myositis, however, the major Fas-mediated cytotoxicity which activates caspases bypasses apoptosis. We therefore evaluated the expression of proteins promoting cell survival, such as bcl-2, bcl-x(l) and cyclin-dependent kinase inhibitors, on muscle biopsies from 14 patients with polymyositis, dermatomyositis, inclusion body myositis and HIV-associated myositis. Our data demonstrate that inflammatory cells are immunoreactive for bcl-x(l), p16 and p57, three apoptosis-preventing proteins. Hence, we assume that these proteins might protect T cells from apoptotic nuclear changes. Our results could explain the non-self-limiting nature of inflammatory myopathies.
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PMID:T-cell anti-apoptotic mechanisms in inflammatory myopathies. 1106 32

A number of lines of investigation suggest that, as is likely the case for other autoimmune diseases, the idiopathic inflammatory myopathies (IIM) develop as a result of specific environmental exposures in genetically susceptible individuals. Current data imply that multiple genes are involved in the etiology of these complex disorders. Targeted gene studies and whole genome approaches have begun to identify several genetic risk factors for autoimmune diseases, but the rarity and heterogeneity of the IIM have limited our knowledge of their associated genes. Current findings suggest that human leukocyte antigen (HLA) genes on chromosome 6, particularly HLA DRB1*0301 and the linked allele DQA1*0501, have the strongest associations with all clinical forms of IIM in white patients. Different HLA alleles, however, may confer risk or protection for myositis in distinct ethnic, serologic, and environmental exposure groups. Non-HLA genetic risk factors, which have been documented for other autoimmune diseases, are now being identified for the IIM. These include polymorphic genes encoding immunoglobulin heavy chains (defined by serologic markers known as Gm allotypes), cytokines and their receptors, and certain proteins that accumulate in the myocyte vacuoles of inclusion body myositis patients. Selected allelic polymorphisms of interleukin-1 receptor antagonist variable number tandem repeats and genes for tumor necrosis factor alpha and interleukin-1 alpha also have recently been associated with IIM. The pathogenic bases for the differences among the many clinically, pathologically and immunologically defined syndromes known as the IIM will be elucidated through a better understanding of the multiple genes that define risks for their development, as well as through investigations of gene-gene and gene-environment interactions.
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PMID:Update on the genetics of the idiopathic inflammatory myopathies. 1109 96

Cytokines, chemokines, and adhesion molecules are important mediators in chronic inflammation and in immune regulation. In idiopathic inflammatory myopathies (IIM), increased expression of proinflammatory cytokines particularly interleukin (IL)-1alpha and IL-1beta, tumor necrosis factor (TNF)-alpha and macrophage inflammatory proteins (MIP)-1alpha, as well as of the inhibitory cytokines transforming growth factor (TGF)-beta was observed in muscle. There was no difference in cytokine and chemokine pattern between polymyositis, dermatomyositis, and inclusion body myositis, which could indicate that similar pathogenetic mechanisms are involved in these subsets of myositis. A prominent finding of IL-1alpha expression in endothelial cells, both in patients with active inflammation and in patients with chronic persisting muscle weakness without inflammation, makes this an interesting molecule in understanding the mechanisms for the pathogenesis of muscle weakness. Involvement of the blood vessels in the pathogenesis of myositis was further supported by increased expression of adhesion molecules and by a phenotypical expression of endothelial cells, resembling high endothelium venules in all three subsets of IIM. The molecular studies to date indicate a role of the microvessels in the pathogenesis of IIM not only in DM, as was previously suggested, but also in PM and IBM. The studies also indicate that IL-1alpha could be a target molecule for new therapeutical interventions.
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PMID:The role of cytokines, chemokines, and adhesion molecules in the pathogenesis of idiopathic inflammatory myopathies. 1112 62

We review the newest advances related to seeking the pathogenic mechanism(s) of sporadic inclusion-body myositis (s-IBM) and present the pathologic diagnostic criteria of s-IBM. We discuss the possible pathogenic role of several themes, such as 1) increased amyloid-beta precursor protein (AbetaPP) and of its fragment Abeta; 2) phosphorylation of tau protein; 3) oxidative stress; 4) abnormal a) signal-transduction, b) transcription, and c) RNA accumulation; 5) "junctionalization" and myogenous" denervation; and 6) lymphocytic inflammation. Evidence is provided supporting our hypothesis that overexpression of AbetaPP within the aging muscle fibers is an early upstream event causing the subsequent pathogenic cascade. The remarkable pathologic similarities between s-IBM muscle and Alzheimer disease (AD) brain are discussed, and the possible cause and significance are addressed.
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PMID:Inclusion-body myositis: newest concepts of pathogenesis and relation to aging and Alzheimer disease. 1120 70

Primary myositis (or inflammatory myopathies) comprises three main groups of diseases, based on clinical and immunohistochemical characteristics: polymyositis (PM), dermatomyositis (DM) and inclusion body myositis. Their clinical presentation and course are disparate, but a common characteristic is immune dysfunction-related inflammation of the striated muscles. Their etiologies are still not fully elucidated but associate environmental and, to a lesser degree, genetic factors. Nevertheless, considerable progress has recently been made in the understanding and management of these diseases.
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PMID:[Inflammatory myopathies]. 1126 23

The cellular isoform of the prion protein (PrPc) is a glycosylphosphatidylinositol-anchored glycoprotein, normally expressed in neural and non-neural tissues, including skeletal muscle. In transmissible spongiform encephalopathies, or prion diseases, PrPc, which is soluble in nondenaturing detergent and sensitive to proteinase K (PK)-treatment, represents the molecular substrate for the production of a detergent-insoluble and PK-resistant isoform, termed PrP(Sc). In human prion diseases, PrP(Sc) accumulation occurs only in brain tissues, with the exception of new variant Creutzfeldt-Jakob disease, where PrP(Sc) is also detected in lymphoid tissues. Increased amounts of prion protein expression and deposition have been described in pathological muscle fibers of two human muscle disorders, called sporadic inclusion-body myositis (s-IBM) and hereditary inclusion-body myopathy, but it is unknown whether accumulated prion protein reflects normal PrPc or PrP(Sc). We investigated the biochemical characteristics of prion protein in normal human muscle, s-IBM, other inflammatory myopathies and denervation atrophy. We report that 1) both the glycoform profile and size of the normal muscle PrPc are different from those of human brain PrPc; 2) in addition to s-IBM, increased PrPc expression is seen in polymyositis, dermatomyositis and neurogenic muscle atrophy, but PrPc glycoforms are unchanged; 3) only the normal PrPc isoform, and not PrP(Sc), is detected in s-IBM. The present results exclude that s-IBM is a prion disease.
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PMID:Increased expression of the normal cellular isoform of prion protein in inclusion-body myositis, inflammatory myopathies and denervation atrophy. 1130 93

Hypertrophy of the cricopharyngeal muscle is a serious clinical condition that can cause severe dysphagic symptoms, including prolonged deglutition and postdeglutitive aspiration. Although the therapeutical concepts are well established, the pathogenic mechanism of cricopharyngeal hypertrophy remains unclear. We present a patient with a ten-year history of progressive dysphagia. The neurological and MRI findings were normal. However, videocineradiography showed severe hypertrophy of the cricopharyngeal muscle. This condition was first treated by injections of botulinum toxin, which did not alleviate the symptoms. Next, myotomy and muscle biopsy were performed. Histological evaluation disclosed lymphoplasmacellular florid myositis, single-fiber atrophy, and muscle fiber necrosis with phagocytosis. There were no signs of inclusion body myositis or oculopharyngeal muscular dystrophy. Our finding of severe cricopharyngeal muscle hypertrophy associated with myositis has been published previously (n = 34). The study presented here shows cricopharyngeal dysphagia associated with various systemic diseases, including motor neuron disease, general granulomatous disease, dermatomyositis, or inclusion body myositis. Isolated changes of the cricopharyngeal muscle were described in 65% of the cases.
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PMID:Cricopharyngeal muscle hypertrophy associated with florid myositis. 1172 Mar 99

Standard drug therapy of adult polymyositis, dermatomyositis and inclusion body myositis includes high-dose corticosteroids and cytotoxic drugs (methotrexate, azathioprine (AZA) and cyclophosphamide). Recent data are in favour of the early introduction of a cytotoxic or immunomodulating drug in addition to corticosteroid therapy. In patients with corticosteroid- and cytotoxic-resistant myositis, promising novel approaches to management include: iv. megadose pulse methylprednisolone combined with cytotoxic drugs, combination therapy with both methotrexate and AZA, cyclosporin, tacrolimus, fludarabine and iv. immunoglobulin (IVIG). Recent advances in the understanding of the role of cytokines and complement, in the pathogenesis of myositis, have led to preliminary therapeutic trials of three biological agents: etanercept, infliximab and anti-C5 monoclonal antibody.
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PMID:Recent advances in the management of adult myositis. 1177 50


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