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Query: UMLS:C0003864 (arthritis)
 69,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibronectin (FN), a high molecular weight glycoprotein, is present in plasma and is a normal structural component of the synovium in the rabbit, as it is in man. FN is also involved in the sequence of changes seen in synovium in experimental antigen-induced arthritis. Its widespread distribution in inflamed synovia in the initial acute phase of induced arthritis probably merely reflects the presence of FN of plasma origin in serous exudates. In established experimental arthritis, FN co-distributes with fibrin, while in synovia undergoing organisation, FN is present intracellularly in several types of mesenchymal cells (suggesting local synthesis) and is deposited on immature collagen fibrils. However, it is no longer present when mature collagen is formed. The persistence of FN, along with fibrin, in inflamed joints, and its involvement in fibrosis, suggest that it may play a significant part in determining the chronicity of this form of experimental arthritis.
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PMID:The role of fibronectin in the pathogenesis of antigen-induced arthritis in the rabbit. 636 45

The sequential changes in the presence of fibronectin in the synovial membrane during the development of antigen-induced arthritis in rabbits were studied using an indirect immunoperoxidase technique on the tissue specimens fixed in formaldehyde, embedded in paraffin and pre-treated with pepsin and testicular hyaluronidase. The relation to the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by van Gieson method, was studied. Initial after the induction of the arthritis the synoviocytes became increased in size and number. The subsynoviocytial tissue was invaded by granulocytes and the number of vessels was increased. Fibronectin in increased amount was seen around the lining cells. After 2-4 weeks a markedly reduced amount of granulocytes were seen together with an increase in the number of macrophages. At this stage, fibronectin was also found together with argyrophilic fibres in the subsynoviocytial connective tissue. After 8-13 weeks the synovial membrane was found hypertrophic and folded. The lining layer was unchanged, but in the subsynoviocytial tissue lymphocytes and plasma cells were more focally arranged. At that time fine fibres, stained by the van Gieson method, were present together with fibronectin and argyrophilic fibres in the subsynoviocytial tissue. The morphological change and the distribution of fibronectin in experimentally induced arthritis correlated temporally to the morphological change and the presence of fibronectin found in experimentally induced granulation tissue.
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PMID:Sequential appearance of fibronectin and collagen fibres in experimental arthritis in rabbits. 636 52

Synovial fluid fibronectin from normal subjects and from patients who have rheumatic inflammatory diseases has been studied and compared with plasma fibronectin. The average fibronectin concentration in synovial fluids from normal subjects was 172 +/- 69 micrograms/ml; it was 721 +/- 315 and 556 +/- 349 micrograms/ml in synovial fluids from patients with rheumatoid arthritis and osteoarthritis, respectively. This is the first report on fibronectin concentrations in normal synovial fluids. Synovial fluid fibronectin from healthy subjects and patients with rheumatoid arthritis or osteoarthritis showed a molecular weight identical to that of plasma fibronectin. All normal and pathologic synovial fluid fibronectins showed a remarkably lower electrophoretic mobility compared with that of plasma fibronectin, when separated according to net molecular charge on agarose gel. Peptides from thermolysin digests of fibronectin from plasma and synovial fluid, when compared on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, showed distinct differences. These data demonstrate that synovial fluid fibronectin represents a molecular form which is structurally different from that of plasma fibronectin. This suggests that synovial fluid fibronectin is locally synthesized, possibly by a cell type which differs from that responsible for the production of the plasmatic fibronectin pool.
Arthritis Rheum 1984 Aug
PMID:Characterization of synovial fluid fibronectin from patients with rheumatic inflammatory diseases and healthy subjects. 646 96

Plasma from 38 patients suffering from one of the five broad clinical subgroups of Psoriatic Arthritis (PA) were studied for soluble plasma Fibronectin (pFn). The mean total concentration of pFn was 453.03 micrograms/ml +/- 142.83 SD, with a significant statistical difference (p less than 0.01) versus a healthy control group matched with respect to sex and age. In order to evaluate the biological role that pFn might play in this pathological condition, observed concentrations were correlated with the degree and duration of the psoriasis and arthritis. In addition, pFn was correlated to some biohumoral parameters that are modified during inflammatory processes (ESR, CRP, sCu, sFe, Hb) and to uric acid levels. Tissue typing (HLA) was done where possible. From our observations, we suggest that pFn most likely is not an acute phase protein and rather than having specificity for a particularly disease, might, in widespread and severe cases be, a general and useful marker of the connective-tissue organizing and repairing response, following its injury.
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PMID:Plasma fibronectin in psoriatic arthritis subgroups. 646 57

A circulating high-molecular-weight glycoprotein called fibronectin plays a part in cell adhesion and migration before phagocytosis and in morphology, differentiation, and metabolism in inflammatory synovial effusions of patients with rheumatic diseases. A technique of nephelometric immunoassay, based on the measurement of an antigen-antibody reaction, was applied to the analysis of fibronectin concentrations in synovial fluids from 20 patients with rheumatoid arthritis (RA) and other diseases (non-RA). RA synovial fluids have a significantly higher concentration than the specimens obtained from Yersinia arthritis patients (n = 12). The mean concentration of other synovial fluids, from 12 patients with osteoarthritis of the knees, did not significantly differ from the synovial fluids of control values obtained from patients who underwent meniscectomy. There was a considerably negative correlation between fibronectin levels and overall indices of inflammatory activity, such as Ritchie articular indices or a whole number of painful rheumatoid arthritis joints. However, a particularly distinct correlation was obtained when raised fibronectin levels were compared with the inflammatory activity of the knee joint, from which the specimen was aspirated. Thus, these findings suggest that the measurements of fibronectin in synovial fluid may be of some differential-diagnostic value in rheumatoid variants, but may only serve as an indicator of inflammatory activity if the joint, from which the specimen is obtained, is taken into account.
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PMID:Different synovial fluid fibronectin levels in rheumatoid variants. 648 13

The inflammatory response to intraarticular urate crystals is known to be variable in gouty arthritis. One source of variability may be the modulation of cellular responses by crystal-bound proteins. We have identified three apolipoproteins among the polypeptides bound to urate crystals exposed to plasma. Identification was first based on their coelectrophoresis with polypeptides from isolated lipoproteins and diminution in the protein coat of crystals exposed to lipoprotein-depleted plasma. The apoproteins were immunochemically identified by the Western blotting technique as apoprotein A-I, apoprotein B (apo B), and apoprotein E. Because neutrophils play a central role in acute gout, we investigated the potential effects of lipoproteins on neutrophil-urate crystal interactions. Plasma profoundly inhibited urate crystal-induced neutrophil luminol-dependent chemiluminescence (CL). Lipoprotein depletion by KBr density gradient centrifugation completely abrogated the inhibitory effect of plasma on urate-induced CL. The inhibitory activity of lipoprotein-depleted plasma was restored by adding back the d less than or equal to 1.25 g/cm3 lipoprotein fraction. Plasma also inhibited urate crystal-induced neutrophil superoxide generation and cytolysis (lactic dehydrogenase loss). This inhibition was significantly diminished by lipoprotein depletion, indicating that the lipoprotein effect was not limited to CL. Lipoprotein-depleted plasma reconstituted with very low, intermediate, and low density lipoproteins (LDL) inhibited crystal-induced CL. High density lipoprotein reconstitution was without effect. Immunodepletion from plasma of all apo B lipoproteins by agarose-bound apo B-specific antibody also removed all inhibitory activity for urate-induced CL. Thus, apo B lipoproteins were shown to be the inhibitory species in plasma. Binding of apo B lipoproteins to urate crystals and inhibition of CL was also seen in the absence of other plasma proteins. In addition, the binding of whole lipoprotein particles to the crystals was verified by detection of crystal-associated cholesterol in addition to the apoprotein. The effects of LDL on urate crystal-induced CL were stimulus specific. Coincubation of urate crystals and neutrophils in the presence of 10 micrograms/ml LDL resulted in 83% inhibition. In contrast, CL responses to a chemotactic hexapeptide, opsonized zymosan, and Staphylococcus aureus were not inhibited by LDL. The effects of depletion of apo B lipoproteins on plasma suppression of urate crystal-induced CL appeared to be unique. Plasma or sera depleted of other urate crystal-binding proteins including fibrinogen, fibronectin, C1q, and IgG retained virtually all their CL inhibitory activity. Lipoproteins containing apo B are thus a major regulator of neutrophil responses to urate crystals. These lipoproteins are present in variable concentration in synovial fluid and may exert an important influence on the course of gout.
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PMID:Lipoproteins containing apoprotein B are a major regulator of neutrophil responses to monosodium urate crystals. 672 56

Fibronectin, a high molecular weight glycoprotein that binds to glycosaminoglycans, fibrinogen or fibrin, and collagen, was identified and quantitated in synovial fluid from patients with various rheumatic diseases. Fibronectin concentration was significantly higher in synovial fluids from patients with rheumatoid arthritis (RA) (697 microgram/ml) than in other synovial fluids. In RA, synovial fluid fibronectin concentration exceeded that in plasma and did not directly correlate with synovial fluid concentrations of albumin, total protein, or fibrinogen. Synovial fluid fibronectin concentration correlated directly with synovial fluid white blood cell count (r = 0.50, P less than 0.005). Fibronectin was present in cryoprotein formed from four rheumatoid synovial fluids.
Arthritis Rheum 1981 Oct
PMID:Detection and quantitation of fibronectin in synovial fluid from patients with rheumatic disease. 697 31

Fibronectin is a glycoprotein secreted by connective tissue cells into their environment and into the blood. Plasma fibronectin has been isolated and used to prepare an antiserum. This has been shown to be specific for fibronectin and unreactive with fibrin(ogen) and collagen, to which fibronectin binds in vitro. The antiserum has been used to examine the distribution of this protein in the synovium in health, in rheumatoid arthritis, and in osteoarthrosis, and to estimate levels in plasma and synovial fluid. The results suggest that fibronectin is synthesised by synovial cells, and the synovial fluid level of fibronectin was found to be about twice the plasma level in rheumatoid arthritis. In long-standing arthritis fibronectin was also found to be codistributed with (presumably by adsorption upon) fibrin and immature collagen in intra-articular structures but was no longer demonstrable in areas where mature collagen had been formed in areas undergoing fibrosis. The possible significance of local fibronectin production within joints in relation to its possible effect on the resolution or continuance of arthritis is discussed.
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PMID:Significance of fibronectin in rheumatoid arthritis and osteoarthrosis. 701 19

1. Plasma fibronectin levels were similar in 60 healthy subjects and 88 with the rheumatoid arthritis. 2. In 42 patients with rheumatoid arthritis synovial fluid fibronectin levels were significantly higher than plasma levels (P less than 0.001). Intermediate fibronectin levels were found in synovial fluid from six patients with psoriatic arthritis, eight patients with osteoarthritis and seven with seronegative arthritis. 3. Plasma and synovial fluid fibronectin levels were not related to indices of inflammatory activity such as the erythrocyte sedimentation rate, the Ritchie articular index or synovial fluid cell counts. Nor did fibronectin behave as an acute-phase protein. 4. Immunofluorescent studies showed that fibronectin was adsorbed on fibrinous debris in rheumatoid arthritic joints. 5. These findings suggest that there is local production of fibronectin by the synovium and suggest that measurement of fibronectin levels in the synovial fluid may serve as an indicator of the tissue response to rheumatoid arthritis.
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PMID:Synovial fluid and plasma fibronectin levels in rheumatoid arthritis. 705 32

The concentration of fibronectin in rheumatoid synovial fluid was found to be 2-3 times higher than in the corresponding plasma. Normal plasma revealed a homogeneous precipitate by cross- immunoelectrophoresis using antifibronectin, while rheumatoid plasma and rheumatoid synovial fluid exhibited a heterogeneous precipitate. The heterogeneous precipitate in rheumatoid plasma was found to be a complex between fibronectin and fibrinogen as evidenced by cross-immunoelectrophoresis. Synovial fluid fibronectin demonstrated a lower molecular weight by gelfiltration on Sepharose CL6B than did normal plasma fibronectin. We suggest that the presence of degraded fibronectin in rheumatoid synovial fluid may be the result of either the degradation of fibrin-fibronectin complexes or the destruction of matrix fibronectin from the synovial tissue.
Arthritis Rheum 1982 Jan
PMID:Different molecular forms of fibronectin in rheumatoid synovial fluid. 706 34


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