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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adhesion of human platelets to type I collagen under arterial flow conditions is extremely fast, being mediated primarily by the alpha 2 beta 1 integrin (glycoprotein Ia/IIa). We have investigated the involvement of cyclic nucleotides in platelet adhesion to soluble native collagen immobilized on Sepharose beads using a new microadhesion assay under arterial flow conditions. To prevent platelet stimulation by thromboxanes and adenosine diphosphate (ADP), experiments were performed with aspirin-treated platelets in the presence of ADP-removing enzyme systems such as creatine phosphate/creatine phosphokinase or apyrase. Rapid reciprocal changes in platelet adenosine 3'5'-cyclic monophosphate (cAMP) and guanosine 3'5'-cyclic monophosphate (cGMP) occurred during adhesion. cAMP levels in adherent platelets were 2.4-fold lower than in effluent platelets or in static controls, whereas cGMP levels were increased 2.4-fold. These results suggest that contact between platelets and collagen stimulates guanylate cyclase and inhibits adenylate cyclase. This occurs in the absence of the platelet release reaction. We also studied short-term effects of agents that regulate cyclic nucleotide synthesis, prostaglandin E1 (PGE1) and sodium nitroprusside (SNP). After only 3.8 seconds at 10 to 30 dyne/cm2, PGE1 (10 mumol/L) increased cAMP 16.4-fold, whereas SNP (50 mumol/L) increased cGMP ninefold and caused a 3.2-fold increase in cAMP. Both PGE1 and SNP rapidly (< 5 seconds) inhibited platelet adhesion in a dose-dependent manner that was correlated with the increase in cyclic nucleotides. Our data suggest that cAMP and cGMP play a regulatory role in the initial phases of platelet adhesion to collagen mediated by the alpha 2 beta 1 integrin receptor.
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PMID:Role of cyclic nucleotides in rapid platelet adhesion to collagen. 751 2

Various regimens to reduce postoperative intraperitoneal adhesion formation have been tested; however, none has been consistently successful. The purpose of this study was to compare the efficacy of three compounds instilled into the peritoneal cavity--32% dextran 70, 0.9% normal saline and sodium carboxymethylcellulose--to no therapy on their ability to prevent postoperative adhesion formation in the New Zealand white rabbit. Bilateral posterior uterine horn incisions and cecal and transverse colon abrasions were performed during a two-phased study on each of 25 rabbits that were randomly assigned in a blind fashion into one of four study groups. Two weeks postoperatively, each rabbit underwent an autopsy to assess the magnitude of intraperitoneal adhesion formation. Adhesion scores were determined by counting the number of adhesions and assigning one or two points for each thin, filmy or dense, broad adhesion. As compared to no therapy, all three substances tested significantly reduced adhesion formation. Although 32% dextran 70 and 0.9% normal saline showed similar results, the degree of adhesion formation was reduced most significantly with sodium carboxymethylcellulose (P < .002) Sodium carboxymethylcellulose is effective in preventing postoperative adhesion formation in the New Zealand white rabbit.
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PMID:Efficacy of intraperitoneal sodium carboxymethylcellulose in preventing postoperative adhesion formation. 752 59

Enterotoxigenic Escherichia coli strains expressing F17 fimbriae bind to the intestinal mucosa of young calves. F17 fimbriae recognize receptors present in the mucus layer and the brush-border membranes from duodenum, jejunum and ileum. The adhesion of E. coli F17 can be inhibited by several glycoproteins. Adhesion is also inhibited by pretreatment of mucus and brush-border membranes with sodium metaperiodate. The use of glycoconjugates as potential adhesion-blockers is further discussed.
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PMID:Inhibition of adhesion of enterotoxigenic Escherichia coli cells expressing F17 fimbriae to small intestinal mucus and brush-border membranes of young calves. 791 67

Adsorption isotherms of poly(styrene) latexes on rat intestinal mucosa were studied under static conditions and analyzed according to different isotherm classifications. Isotherms of latexes with a particle size up to 670 nm had the characteristic shape of a disperse adsorbate on a porous adsorbent. Plateaus were reached at latex concentrations of about 2.5 g/L. The results indicated an increase in adsorption with the size and the hydrophilicity of the latexes. Typically, a surfactant-free carboxylate latex of 230 nm had a plateau of 0.66 g/m2, and a latex of 320 nm with added sodium dodecyl sulfate had a plateau of 0.881 g/m2. Surfactant-free carboxylate latex of 2 microns had a Langmuirian isotherm with a plateau level of 2.616 g/m2, which corresponded to a monolayer of adsorbed particles on the surface of mucosa. Desorption studies showed that the adsorption was irreversible. Adhesion to the mucous gel layer would therefore be limited by the mucus turnover.
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PMID:Mucoadhesion of latexes. II. Adsorption isotherms and desorption studies. 805 36

Human umbilical vein endothelial cells (HUVEC) were used as an experimental host model to investigate the mechanism(s) of streptococcal adhesion in infective endocarditis. Adhesion activity of Streptococcus gordonii was maximal during the logarithmic phase of growth and was greatly reduced or eliminated by pretreatment of bacteria with heat, formaldehyde, or trypsin. At saturating numbers of streptococci, an average of 81 bacteria were bound per HUVEC. Streptococcal adhesion was inhibited by low-molecular-weight dextran and heparin but not by sucrose, fibronectin, or laminin. Adhesion was also prevented by pretreatment of HUVEC with proteins dissociated from the surface of S. gordonii with 10 mM EDTA or isolated from spent culture medium. Western blot (immunoblot) assays detected a single adhesion protein of 153 kDa (AP153) on HUVEC after incubation with unfractionated extracts of streptococci. The adhesin exhibited glucosyltransferase (GTF) activity when incubated with sucrose and Triton X-100 after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The AP153 was purified by affinity chromatography on dextran beads and show to have binding activity for HUVEC, GTF activity, an amino acid composition similar to that reported for GTF of S. gordonii, and the ability to inhibit S. gordonii adhesion. Incubation of the streptococci with antibodies to the adhesin inhibited bacterial attachment to HUVEC monolayers. These results indicate that surface-localized GTF mediates adhesion of S. gordonii to HUVEC in vitro and may serve as a mechanism for colonization of the endocardium in infective endocarditis.
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PMID:Glucosyltransferase mediates adhesion of Streptococcus gordonii to human endothelial cells in vitro. 818 39

The mechanisms responsible for the accumulation of eosinophils at sites of allergic and other inflammatory reactions are unknown, but recent studies have implicated both eosinophil and endothelial adhesion molecules in this process. However, less well studied have been the adhesive interactions between eosinophils and the subendothelial basement membrane and interstitial connective tissues. To test the hypothesis that eosinophils might interact with extracellular matrix proteins, we analyzed purified human eosinophils for the expression and function of various beta 1 integrins. Using indirect immunofluorescence and flow cytometry, purified eosinophils from mildly allergic donors were found to consistently express the integrin subunits beta 1 (CD29), alpha 4 (CD49d, very late activation antigen [VLA]-4 alpha), and alpha 6 (CD49f, VLA-6 alpha). No significant expression of the alpha 1, alpha 2, alpha 3, alpha 5, or beta 4 subunits was detected. Platelet contamination of the eosinophil preparations was excluded by light microscopy and by the inability to detect expression of platelet glycoproteins alpha v, CD41b, and CD42b. Immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of eosinophils confirmed the expression of cell-surface beta 1, alpha 4, and alpha 6. Furthermore, eosinophils purified from allergic donors were shown to adhere to plate-bound laminin, but not to type 1 or type 4 collagen. Adhesion to laminin was concentration-dependent, required divalent cations, and was completely and specifically inhibited by the anti-alpha 6 monoclonal antibody (MoAb) GoH3 and by the anti-beta 1 MoAb 33B6. Interestingly, the anti-beta 1 MoAb 18D3 (which like 33B6 blocks eosinophil binding to VCAM-1) did not inhibit eosinophil adhesion to laminin, suggesting that there are functionally distinct epitopes on the beta 1 subunit. Eosinophils purified from 4 healthy, nonallergic donors also showed alpha 6-dependent adhesion to laminin, although these cells adhered less well. These studies establish the expression of alpha 6 beta 1 on human eosinophils and document its function as a laminin receptor. Interaction of eosinophil alpha 6 beta 1 with laminin, eg, in basement membranes, may contribute to the localization of these cells at inflammatory sites in vivo.
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PMID:Expression of a functional laminin receptor (alpha 6 beta 1, very late activation antigen-6) on human eosinophils. 821 35

Postoperative adhesions are a major cause of bowel obstruction and infertility. Since mast cells in the intestinal wall have been shown to degranulate after bowel manipulation, we investigated a possible role for these cells in peritoneal adhesion formation. Adhesions were created in weanling rats using cecal scraping and the application of 95% ethanol. The rats were treated with saline or one of two mast cell stabilizers, disodium cromoglycate (DSCG) or nedocromil sodium (NED), intraperitoneally 30 minutes before laparotomy and at the time of abdominal closure. The adhesions were assessed blindly 1 week later using a standardized scale. When the results in rats treated with DSCG were compared with those in rats treated with saline, the DSCG rats had significant attenuation of adhesion formation at 2 mg/kg (1.05 +/- 1.0 versus 2.15 +/- 0.8) and 10 mg/kg (1.2 +/- 0.9 versus 2.71 +/- 0.5). The application of NED decreased adhesions at a dose of 100 mg/kg (1.33 +/- 1.2 versus 2.4 +/- 0.8) but not at 10 mg/kg (2.4 +/- 0.8 versus 2.4 +/- 0.8). Histologic analysis using toluidine blue staining was done to assess the effect of DSCG on mast cell degranulation in the same adhesion model. DSCG significantly decreased the number of degranulated mast cells in the bowel wall when compared with saline (7.16 +/- 0.6 mast cells/high-power field [hpf] versus 12.4 +/- 1.9 mast cells/hpf). These data suggest that mast cells play an important role in the initial stages of peritoneal adhesion formation. In the future, pharmacologic inhibition of mast cell degranulation may be a useful adjunct for the prevention of postoperative adhesions.
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PMID:Role of mast cells in peritoneal adhesion formation. 838 Mar 13

Adhesion of three Lactobacillus strains onto human epithelial intestinal Caco-2 and Int-407 cell lines was compared. More adhesion occurred onto Int-407. The trypsin and sodium periodate pretreatment of bacteria revealed different mechanisms of adhesion depending on the Caco-2 and Int-407, involving carbohydrates and proteins. The absence of adherence for one Lactobacillus strain onto both cell lines indicated the specificity of the adhesion. Electron microscopic observations showed that bacteria adhered by underlying the brush border microvilli of the Caco-2 surface contrasting onto the Int-407 which entrapped and surrounded them by fimbrial extracellular cell matrix material.
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PMID:Comparison of the adherence of three Lactobacillus strains to Caco-2 and Int-407 human intestinal cell lines. 869 70

Adhesion of myeloid leukemia cells to the bone marrow (BM) microenvironment is mediated in part by Beta 1 and Beta 2 integrins. Cells of the erythroleukemia line K562, derived from a patient with chronic myeloid leukemia, bind to BM fibroblasts (BMFs) but the adhesion cannot be accounted for by integrins or other known adhesion proteins including CD44 or members of the Ig or selectin families. Membrane fragments from K562 cells were radioiodinated and allowed to adhere to BMF monolayers. Adherent proteins were solubilized together with the fibroblasts, analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and visualized by autoradiography. Four adherent proteins were consistently observed. Two of these, with reduced molecular weights of 52 kD and 35 to 37 kD, were prominent. Addition of soluble thrombospondin and heparin but not fibronectin inhibited binding of K562 membrane proteins to adherent BMFs and immobilized thrombospondin- and heparin-bound K562 proteins. The 52-kD protein has a multimeric structure nonreduced and has characteristics of a glycoprotein. Its adhesion to fibroblasts is divalent cation and temperature sensitive. The 35- to 37-kD protein, whose function is divalent cation but not temperature sensitive, is phosphoinositol-linked and has characteristics identical to an adherent 35- to 37-kD protein identified on murine progenitor cells. Membrane preparations from two cases of acute myeloid leukemia showed an adherent 35- to 37-kD protein and in one case an adherent 52-kD protein without other adherent bands. A K562 subclone with reduced adherence to BMFs showed reduced amounts of adherent 52-kD and 35- to 37-kD proteins. These proteins may be responsible for the adhesion of malignant and normal hematopoietic progenitor cells to the BM microenvironment.
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PMID:Identification of novel K562 membrane proteins that adhere to bone marrow fibroblasts. 870 84

The goal of this study was to characterize salivary components of titanium pellicles and to determine how experimental pellicles affect adhesion of several strains of streptococci to titanium surfaces. Titanium experimental pellicles were formed by incubation of fresh human parotid or human submandibular-sublingual saliva on pure titanium beads. Pellicle was recovered from the beads using sodium dodecyl sulfate buffer and was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting to identify adsorbed salivary components. Streptococcus anginosus, S. oralis, and S. salivarius recovered from in vivo titanium plaque and five reference strains of streptococci were used in adhesion assays to titanium beads with and without experimental salivary pellicles. The experimental pellicle formed on titanium was found to be composed of selected proteins from human parotid and human submandibular-sublingual saliva. Salivary alpha-amylase and proline-rich proteins were found in all experimental pellicles, while sIgA, high-molecular weight mucin, and proline-rich glycoproteins were detected in one of the experimental pellicles examined. Adhesion of fresh isolates and reference stains of S. anginosus, S. oralis, and S. salivarius to saliva-coated titanium was reduced compared to that of titanium without saliva coating. However, adhesion of laboratory strains of S. gordonii and S. sanguis was found to be significantly greater to experimental pellicles of human submandibular-sublingual saliva than was the adhesion of the fresh isolates, suggesting that streptococci-colonizing implant surfaces may be inherently less adhesive than other bacterial strains. This study found that salivary pellicles are selectively formed on titanium and mediate in vitro adhesion of streptococci.
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PMID:Experimental salivary pellicles formed on titanium surfaces mediate adhesion of streptococci. 880 39


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