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

The calcium-independent mechanism of cell adhesion was studied in normal and polyoma virus-transformed BHK cells. The degree of Ca2+-independent adhesion was greatly reduced in pyBHK cells, whereas CA2+-dependent adhesion occurred to the same degree as in BHK cells. This decrease was shown not to be caused by simple masking of the adhesion sites or by their altered sensitivity to trypsin. Adhesion-blocking antibodies were used to identify molecules responsible for Ca2+-independent adhesion. The antibodies precipitated surface molecules specific for adhesion-competent cells. These have tentatively been named CIDSBHK and CIDSpyBHK. Both were glycoproteins with respective apparent molecular weights of 120K and 125K. CIDSpyBHK incorporated 3H-glucosamine more than CIDSBHK did. Possible modification of the Ca2+-independent adhesion mechanism in pyBHK cells is discussed.
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PMID:Modification of the calcium-independent mechanism of cell adhesion in transformed BHK cells. 632 Oct 41

Group B streptococci adhere to influenza-virus infected canine kidney epithelial cells but not to uninfected cells. For studies of the molecular nature of this interaction the bacteria were radiolabelled and a quantitative binding assay was developed with which the following properties of the system were observed. (1) Adhesion was specific for group B streptococci (GBS); streptococci from other serological groups did not bind and did not inhibit adhesion of radioactive GBS. (2) Binding of GBS to infected kidney cells was inhibited by the addition of cell walls from GBS to the kidney cell monolayers. (3) Preincubation of GBS with free influenza virus prevented their attachment to infected kidney cell monolayers. With a centrifugation type of assay, labelled influenza virus bound to GBS. This binding could be inhibited by several glycoproteins after removal of the terminal sialic acid. Asialo-glycopeptides of the complex type, isolated from these inhibitory glycoproteins, also bound to GBS. The influenza viral glycoproteins have been partially characterized and shown to contain a glycosylamine type of complex oligosaccharide. This type of oligosaccharide is biosynthesized by means of lipid-linked saccharide intermediates. Several antibiotics such as tunicamycin and streptovirudin, and other inhibitors such as 2-deoxyglucose and glucosamine, inhibit this lipid-linked pathway. These inhibitors also prevent the formation of mature influenza virus as well as the adherence of group B streptococci. Other inhibitors of protein glycosylation should be valuable as tools for improving further our understanding of the mechanism of cell adhesion.
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PMID:Effect of inhibitors on glycoprotein biosynthesis and bacterial adhesion. 702 Oct 87

Changes in glycoconjugate production have been reported for tumor cells. In this study, we investigated the glycoconjugate expression pattern in normal human melanocytes and in a panel of 6 human melanoma cell lines with different metastatic capacity after s.c. inoculation into nude mice. Glycoconjugates were labeled in vitro with [35S] sulphate and [3H] glucosamine, purified from cells and culture medium by column chromatography and identified by treatment with specific glycosidases. Characterization of the purified glycoconjugate fractions as well as alcian-blue staining of xenograft lesions revealed that hyaluronic acid (HA) is the main glycoconjugate produced by all cell lines. Highly metastatic cell lines expressed higher levels of HA than melanocytes and than weakly metastatic or non-metastatic cell lines. In addition, a shift in dominance from chondroitin-sulphate proteoglycan to heparan-sulphate proteoglycan was observed with increasing metastatic capacity. We also studied the expression and binding activity of the HA receptor CD44. Immunoprecipitation experiments indicated high CD44 synthesis only in highly metastatic cell lines, but FACS analysis demonstrated approximately the same surface expression in melanocytes as in all cell lines. Adhesion assays to immobilized HA showed that CD44 can be present in an inactive or an active conformation. Our data suggest that a combination of increased HA production and the expression of CD44 on the cell surface may be associated with high metastatic potential of human melanoma cell lines in nude mice.
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PMID:Glycoconjugate profile and CD44 expression in human melanoma cell lines with different metastatic capacity. 753 56

Adhesion of A-121 human ovarian carcinoma cells to extracellular matrix is partly mediated via interaction between galaptin, an endogenous beta-galactoside-binding lectin present in extracellular matrix, and specific cell surface carbohydrate receptors identified as lysosomal associated membrane proteins, lamp-1 and lamp-2. In this study, we report that adhesion of human ovarian carcinoma cells to polystyrene plates coated with polymerized human splenic galaptin can be inhibited by polyclonal antibodies raised against lamp-1 and lamp-2 molecules and by pretreatment of A-121 human ovarian carcinoma cells with glucosamine analogs: 2-acetamido-1,4,6-tri-O-acetyl-3- deoxy-3-fluoro-alpha-D-glucopyranose (3-F-GlcNAc) and 2-acetamido-1,3,6-tri-O-acetyl-4-deoxy-4-fluoro-alpha-D-glucopyranose (4-F-GlcNAc). A 48-h exposure of A-121 cells to individual sugar analogs, or to a combination of the two, resulted in a concentration-dependent inhibition of cellular attachment to polymerized galaptin. Both drugs inhibited glycoprotein biosynthesis as measured by cellular incorporation of labeled [3H]glucosamine and [3H]fucose with negligible effects on [3H]thymidine and [3H]leucine incorporation and cell growth. As a result of drug action on glycoprotein biosynthesis, an alteration in the structure of the galaptin receptor was noted by indirect immunofluorescence and Western blot analysis. Moreover, probing gels of cell extracts with anti-lamp antibodies or Datura stramonium lectin demonstrated significant changes in the reactivity and pattern of glycoprotein staining, suggesting an effect of sugar analogs on the glycosylation of various cellular receptor molecules. The greatest change was observed when tumor cells were exposed to a combination of the two sugar analogs. These studies suggest that specific endogenous lectins and their surface receptors play a role in tumor cell adhesion and perhaps metastasis and may serve as suitable targets for therapeutic exploitation.
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PMID:Inhibition of lectin-mediated ovarian tumor cell adhesion by sugar analogs. 807 32

The adhesion and viability of dissociated neurons of rat cerebral hemispheres onto methacrylate and methacrylamide hydrogels, either unmodified or containing collagen, basement membrane proteins, and glucosamine, were measured in vitro. The degree of cell adhesion was affected by properties of the polymers such as hydrophilicity, hydrophobicity, presence of reactive chemical groups, and incorporation of biological molecules. Adhesion was promoted by attachment of glucosamine to the polymer backbone. Viability was enhanced by the presence of basement membrane proteins within the polymer network. Morphological studies of cells seeded, both onto and within the polymeric matrices, demonstrated the capacity of such substrates to support neuritic outgrowth. The potential of these in vitro assays in the design of polymeric matrices as neural tissue repair promoter substrate is discussed.
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PMID:Synthetic polymer derivatives as substrata for neuronal adhesion and growth. 845 92

The adhesion of Lactobacillus rhamnosus GG to human enterocyte-like Caco-2 cells was not inhibited by eight carbohydrates tested, namely N-acetyl-glucosamine, galactose, glucose, fructose, fucose, mannose, methyl-alpha-D-mannopyranoside and sucrose. The degree of hydrophobicity predicted the adhesion of L. rhamnosus GG to Caco-2 cells. L. rhamnosus GG, however, was able to compete with Escherichia coli and Salmonella spp. of low hydrophobicity and high adhesin-receptor interaction for adhesion to Caco-2 cells. The interference of adhesion of these gastrointestinal (GI) bacteria by L. rhamnosus GG was probably through steric hindrance, and the degree of inhibition was related to the distribution of the adhesin receptors and hydrophobins on the Caco-2 surface. A Carbohydrate Index for Adhesion (CIA) was used to depict the binding property of adhesins on bacteria surfaces. CIA was defined as the sum of the fraction of adhesion in the presence of carbohydrates, with reference to the adhesion measured in the absence of any carbohydrate. The degree of competition for receptor sites between Lactobacillus casei Shirota and GI bacteria is a function of their CIA distance. There were at least two types of adhesins on the surface of L. casei Shirota. The study provides a scientific basis for the screening and selection of probiotics that compete with selective groups of pathogens for adhesion to intestinal surfaces. It also provides a model for the characterisation of adhesins and adhesin-receptor interactions.
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PMID:Competition for adhesion between probiotics and human gastrointestinal pathogens in the presence of carbohydrate. 1221 84

Staphylococcus epidermidis is now well established as a major nosocomial pathogen associated with infections of indwelling medical devices. The major virulence factor of these organisms is their ability to adhere to devices and form biofilms. However, it has not been established that adherence and biofilm formation are closely linked phenotypes for clinical isolates. In this study, the initial adhesion to different materials (acrylic and glass) of 9 clinical isolates of S. epidermidis, along with biofilm-positive and biofilm-negative control strains, was assayed using physico-chemical interactions to analyze the basis for bacterial adherence to the substratum. X-ray photo electron spectroscopy (XPS) analysis of the cell surface elemental composition was also performed in an attempt to find a relationship between chemical composition and adhesion capabilities. Biofilm formation on the two surfaces was evaluated by dry weight measurements. Human erythrocytes were used to evaluate the ability of S. epidermidis strains to cause hemagglutination, an indicator of the production of a poly-N-acetyl glucosamine cell surface polysaccharide also involved in biofilm formation. The clinical isolates exhibited different cell wall physico-chemical properties, resulting in differing abilities to adhere to surfaces. Adhesion to hydrophobic substrata for all strains occurred to a greater extent than that to hydrophilic surfaces. Bacterial cell hydrophobicity seemed to have little or no influence on adhesion. X-ray photoelectron spectroscopy analysis showed a high ratio of oxygen/carbon for all strains, which is a common characteristic of S. epidermidis species. No relevant relationship was found between XPS data and adhesion values. All strains forming biofilms were able to agglutinate erythrocytes. However, no direct relationship was found between the amount of biofilm formed and the initial adhesion extent. These results indicate that high levels of initial adherence do not necessarily lead to thick biofilm formation. These two aspects of the pathogenesis of medical device related-infection may need to be evaluated independently to ascertain the contribution of each to the virulence of S. epidermidis causing device-related infections.
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PMID:Quantitative analysis of adhesion and biofilm formation on hydrophilic and hydrophobic surfaces of clinical isolates of Staphylococcus epidermidis. 1586 49