Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Purification and partial characterization of adherence-inhibiting factor (AIF) of platelet-granule fraction in guinea pig were studied. When freshly prepared platelet-granule fraction was subjected to a gel filtration, two neutrophil adherence-inhibiting peaks, designated AIF-I (2,800 kDa) and AIF-II (12 kDa), appeared. AIF-I was sensitive to diisopropylfluorophosphate (DFP) and originated from lysosomes, whereas AIF-II was insensitive to DEP and localized in alpha-granules. Both AIFs were released from platelets by a thrombin stimulation. As the total activity of AIF-I was about 5-fold higher than that of AIF-II, AIF-I was purified and characterized. When purified AIF-I was analyzed on SDS-polyacrylamide gel electrophoresis, the 340 kDa protein band and the other large protein band were observed. Under reducing condition, AIF-I was separated into three components (340, 190 and 165 kDa). AIF-I significantly inhibited neutrophil adherence to artificial substrata and to type IV collagen-coated plastic surface, but not to fibronectin- or plasma-coated plastic surfaces, suggesting that AIF-I inhibits neutrophil adherence not only via nonspecific adsorption sites but also via type IV collagen receptors.
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PMID:Purification and partial characterization of platelet-derived adherence-inhibiting factor in guinea pig. 259 6

Fibronectin, an opsonic glycoprotein has been shown to exist in fragmented forms in serum and synovial fluid. Some fragments in synovial fluid appear to be polyethylene glycol (PEG) precipitable, suggesting incorporation into immune complexes (IC). PEG precipitation, SDS-PAGE and immunoblotting were used to determine whether PEG precipitable fragments are real or artefactual. Disease specificity of fragmentation and IC incorporation of fibronectin and other proteins were also studied using these techniques. PEG precipitable fragments do not appear to be artefactual, although some fibronectin fragments are cryoprecipitable. Protein fragments showed similar distributions in whole serum and synovial fluid, disease specific differences being confined to PEG precipitates. Rheumatoid arthritis (RA) synovial fluid PEG precipitates displayed the greatest array of fragmented immunoglobulins and fibronectin. No PEG precipitates contained albumin fragments. Protein fragments in IC may impair their effective removal from RA joints. Accumulated IC could lead to tissue damage via complement activation.
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PMID:Fragmented fibronectin and other synovial fluid proteins in chronic arthritis: their relation to immune complexes. 260 81

The interaction between the epithelial cells and the subjacent mesenchymal cells in the airway is thought to play a major role during tissue repair after airway injury and lung morphogenesis. To evaluate this interaction, we cultured human lung fibroblasts, and bovine and human bronchial epithelial cells, and determined that bronchial epithelial cell-conditioned medium has a chemotactic activity for lung fibroblasts. This activity had the characteristics of protein: it was nondialyzable, heat-labile, pepsin-labile, acid-stable, and lipid-inextractable. Molecular sieve chromatography on Sephadex G-150 and affinity chromatography on gelatin-Sepharose revealed that there was one peak of chemotactic activity in high molecular weight range, which bound to gelatin, thus suggesting that the chemotactic factor might be fibronectin. Production and secretion of fibronectin into the culture media were demonstrated by biosynthetic incorporation of radioactive amino acid into fibronectin followed by immunoprecipitation on SDS-PAGE and autoradiography. Release into the culture medium was confirmed by ELISA. The identity of fibronectin as the chemotactic activity was confirmed by the addition of antifibronectin antibody to the conditioned medium, which inhibited chemotaxis in dose-dependent manner. Thus, bronchial epithelial cells produce fibronectin which can function as a chemotactic factor for lung fibroblasts. This production of fibronectin by bronchial epithelial cells may play an important role in regulating interaction between the bronchial epithelial cells that line the lumenal surface of the bronchial epithelial wall and the mesenchymal fibroblasts that underlie the bronchial epithelial basement membrane.
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PMID:Bronchial epithelial cells produce lung fibroblast chemotactic factor: fibronectin. 262 56

A high molecular weight extracellular protein has been purified from cell culture medium of Ewing's sarcoma cell lines, by high performance liquid chromatography and electroelution from SDS-PAGE electrophoresis. This protein has an apparent molecular mass of about 500,000 Da on SDS-PAGE. Immunoprecipitation studies with several extracellular matrix glycoproteins (laminin, fibronectin) specific antisera indicate it is a separate protein. Reduction of disulphide bonds with 2-ME or DTT fails to significantly alter its migration on SDS-PAGE gels, other than a slight apparent increase in molecular mass, indicating an apparent single polypeptide chain structure. The slightly greater mobility observed in unreduced gels suggests one or more regions of intrachain disulfide bonding. It is sensitive to pepsin and trypsin, but resistant to bacterial collagenase indicating that it does not contain collagenous domains. Metabolic labelling with 3H-proline, 3H-leucine, and 35S-methionine indicate that this protein is proline-poor, but leucine, and especially methionine, rich. Sodium 35S-sulfate incorporation is totally negative and treatment with glycosaminoglycan degrading enzymes has no effect on the mobility of the protein on gels, unlike typical proteoglycans. This protein appears by rotary shadowing electron microscopy as a long, thin, filamentous molecule at least 500 nm (0.5 um) in length. The tissue localization and function are unknown at this time, but are under active investigation.
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PMID:A novel 500,000 Da, linear, single chain extracellular protein synthesized by several childhood tumors. 263 60

Fibronectinolytic activity from two Gram-positive microorganisms (Streptococcus mutans and Bacterionema matruchotii), and from three Gram-negative oral bacteria (Bacteroides intermedius, Bacteroides gingivalis and Haemophilus actinomycetemcomitans) were compared. 125I-labelled human plasma fibronectin (FN) was incubated either either with bacterial extracts or with concentrated culture medium samples and the patterns of FN-degradation products were determined by SDS-PAGE. Results to date have shown that Streptococcus mutans, Bacterionema matruchotii and Haemophilus actinomycetemcomitans were unable to degrade FN. On the other hand the Gram-negative Bacteroides intermedius and Bacteroides gingivalis were shown to contain Fn-degrading activity. The highest activity was found in the bacterial extracts of Bacteroides gingivalis. Inhibition assays demonstrated that fibronectinolytic activity of Bacteroides gingivalis occurred predominantly by cysteine proteinase(s) while that of Bacteroides intermedius by a common action of serine and cysteine proteinases.
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PMID:A comparison of fibronectinolytic activities from several oral bacteria. 269 52

We have purified the platelet membrane glycoprotein Ia-IIa complex by detergent solubilization and sequential affinity chromatography on Concanavalin A-Sepharose and collagen-Sepharose. The complex, which is identical to the VLA-2 complex of lymphocytes and other cells and contains subunits of 160 and 130 kD on SDS-PAGE, was labeled with 125I and incorporated into phosphatidyl choline liposomes. The liposomes, like intact platelets, adhered to collagenous substrates in an Mg++-dependent manner with a K'a(Mg++) of 3.5 mM. Little adhesion of the liposomes to collagen occurred when Mg++ was replaced by Ca++ or EDTA. Calcium ions inhibited the Mg++-dependent adhesion with a K'i(Ca++) of 5.5 mM. Liposomes containing the Ia-IIa complex adhered to substrates composed of types I, II, III, and IV collagen, but did not effectively adhere to substrates composed of type V collagen or gelatin. Adhesion to collagen was specific. The liposomes did not adhere to fibronectin, vitronectin, laminin, thrombospondin, fibrinogen, or von Willebrand factor substrates. The monoclonal antibody P1H5, which specifically immunoprecipitated the Ia-IIa complex, also specifically inhibited the Mg++-dependent adhesion of both platelets and Ia-IIa-containing liposomes to collagen substrates. These findings provide additional evidence that the platelet membrane Ia-IIa complex is the mediator of Mg++-dependent platelet adhesion to collagen and suggest that the VLA-2 complex may also function as an Mg++-dependent collagen receptor in other cells.
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PMID:The membrane glycoprotein Ia-IIa (VLA-2) complex mediates the Mg++-dependent adhesion of platelets to collagen. 271 83

A procedure for extraction and quantification of fibronectin in human aortic tissue is described in this paper. Dried, defatted samples of human aortic tissue were subjected to sequential extraction with (i) 0.89% NaCl, 10 mmol/l Tris/HCl, pH 7.4, (ii) 5 mg/ml heparin, 2 mol/l urea and (iii) collagenase digestion. More than 75% of hexosamine-containing molecules were solubilized by this procedure. Immunoblotting of extracted proteins separated by SDS-PAGE showed that extracted fibronectin had a mobility in the same range as that of plasma fibronectin. Fibronectin ELISA performed on these extracts gave dilution curves parallel to the standard curve, the sensitivity was 2.7 micrograms/l. Recoveries of a fibronectin standard added to the NaCl, heparin/urea and collagenase solutions during extraction were 97%, 90% and 84% respectively. Normal aortic tissue from 31 patients was subjected to the sequential extraction scheme and fibronectin quantification in the various extracts demonstrated that 4.52 +/- 1.79 micrograms was dissolved in the NaCl extracts, 5.41 +/- 2.28 in the heparin/urea extract and 1.08 +/- 0.43 in the collagenase digest, respectively. (Values are expressed as micrograms fibronectin/10 mg dry, defatted tissue (mean +/- SD]. Our results indicate that the ELISA method can be applied for the measurement of fibronectin in extracts of human aortic tissue. This might be useful in the study of diseases where alterations in arterial fibronectin content may be expected.
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PMID:Quantification of fibronectin in extracts of human aortae by an ELISA. 274 Aug 16

The ability of NK cells to synthesize and secrete fibronectin (FN), an extracellular matrix glycoprotein which plays a key role in many biologic processes including cellular adhesion, morphology, cytoskeletal organization, cell migration, and invasiveness, was studied. By using affinity-purified polyclonal antibodies directed against human cellular or plasma FN, the presence of FN was evidentiated on Percoll-purified rat large granular lymphocyte or on a large granular lymphocyte tumor cell line (CRC) by flow cytometry and immunoelectron microscopy. Its expression increased after NK cell activation by poly I:C administration. Biochemical analysis by immunoprecipitation and SDS-PAGE indicated that FN was associated to cell surface and secreted in the supernatant in a molecular form similar to that of FN from L929 fibroblasts. In an attempt to understand the role of FN in the NK cell function, we found that an antibody against human plasma FN and its F(ab')2 fragment inhibited NK cytotoxicity against YAC-1 target at the effector cell level. Inhibition occurred at the postbinding level, because F(ab')2 anti-FN inhibited induction of phosphatidylinositol hydrolysis by YAC-1 target cells, whereas binding to target cells was not affected. The possible role of FN in the NK cytotoxic function is suggested.
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PMID:Rat natural killer cells synthesize fibronectin. Possible involvement in the cytotoxic function. 277 21

We established and characterized five cell lines derived from human malignant gliomas (four glioblastomas multiforme and one highly anaplastic astrocytoma). All cell lines exhibited tumor cell morphology and growth kinetics, and anchorage-independent growth in soft agar. Cytogenetic analysis revealed significant aneuploidy in all five cases as well as clonal chromosomal alterations unique to each cell line. No cell line was tumorigenic in athymic mice. Two of the cell lines were sensitive to carmustine (BCNU) in monolayer and soft-agar cultures. Electron microscopy showed marked variability between cell lines in the number and structure of intracytoplasmic organelles; SF-126 formed collagen fibers in vitro. Immunohistochemical analysis of the surgical specimens showed variable expression of glial fibrillary acidic protein (GFAP) in malignant astrocytes; positive immunostaining for glycoproteins of the extracellular matrix was found predominantly in perivascular regions. In early-passage cultures, only cell line SF-295 expressed GFAP; at establishment, none of the cell lines expressed GFAF or glutamine synthetase. Fibronectin and laminin were expressed by all cell lines in early-passage culture, but expression of these glycoproteins at establishment was variable. Only SF-126 was positively identified by immunostains for procollagen III; this was also the only cell line in which DEAE-cellulose chromatography and SDS-PAGE demonstrated interstitial collagen synthesis. These well-characterized glioma-derived cell lines may now serve as useful tools with which to study the cell biology of gliomas. The synthesis of interstitial collagen by a glioma-derived cell line may suggest a derivation from vascular mesenchymal elements, either reactive or transformed, in the original heterogeneous malignant glioma, rather than from a glial precursor cell.
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PMID:Establishment and characterization of five cell lines derived from human malignant gliomas. 282 96

In this report we describe the isolation and characterization of a neutral metalloproteinase, from human small cell lung cancer cells, which degrades a wide range of connective tissue proteins. Treatment of tumor cytosol by ammonium sulphate precipitation followed by zinc chelated column chromatography, anion exchange chromatography, and gel filtration chromatography yielded a single enzymatically active protein, which on SDS-PAGE appeared as a diffuse band of 65,000-70,000 daltons. The tumor metalloproteinase, which was inhibited by metal chelators and serum, was able to digest gelatin, type I collagen, type IV collagen, laminin, and fibronectin. We propose that the capacity of this proteinase to degrade both components of blood vessel basement membranes and other connective tissue matrices facilitates the dissemination of human lung cancer cells during the multistep process of metastasis.
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PMID:Characterization of a connective tissue degrading metalloproteinase from human small cell lung cancer cells. 283 54


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