Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adhesion of Staphylococcus aureus was investigated on flat silicon oxide surfaces that had been incubated in human plasma at different concentrations. Adhesion of bacteria did not occur at high incubation concentrations of plasma or when the surface had been incubated in egg albumin. However, significant adhesion was observed when plasma was diluted. With the use of antibody method, it was noted that the adhesion of the bacteria coincided with adsorbed fibrinogen, and possibly also with IgG. We also investigated the effect of "narrow space" on the adsorption of blood plasma and subsequent adhesion of S. aureus. In these experiments, blood plasma was incubated under a convex lens placed upside-down on the silicon oxide surface. This method creates a continuous gradient of space from the contact point of the lens and outward. After rinsing off the plasma and the lens, the surface was incubated with a suspension of S. aureus followed by quantification of the attached bacteria by means of optical methods. Adhesion of bacteria occurred in several circular zones that were easily detectable with the naked eye or by the means of simple optical methods. In addition, in these experiments, adhesion coincided with adsorbed fibrinogen or IgG at the surfaces. The increased bacterial adhesion to surfaces incubated in diluted plasma, or plasma incubated in narrow space, is a variant of the so-called "Vroman effect." With a model protein system consisting of fibrinogen and IgG and the corresponding antibodies, we demonstrate that "dilution" and "incubation in narrow space" are two phenomenologically similar methods.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Lens-on-surface method for investigating adhesion of Staphylococcus aureus to solid surfaces incubated in blood plasma. 808 45

Model biomaterial surfaces with well defined chemistry were prepared from close-packed alkyltrichlorosilane monolayers on polished silicon and glass. The outermost molecular groups which come in direct contact with the biological environment were varied across a wide range of oxidation states by employing -CF3, -CH3, -CO2CH3, and -CH2OH terminal functionalities. Characterization by contact angles, surface spectroscopy, and ellipsometry verified that these model surfaces could be repeatedly prepared with good consistency for routine use to study biomolecule adsorption onto model surfaces. Adhesion of canine endothelial cells and the adsorption of proteins (human serum albumin and human fibrinogen) as well as series of synthetic defined oligopeptides to these model surfaces have been studied. Endothelial cells attachment and growth were in the rank order of: -CH2OH > -CO2Me > -CH3 > -CF3. The peptides were comprised of different alternating sequences of lysine, leucine, and tryptophan residues. These structural differences imparted different amphiphilic characters that led to measurable differences in the adsorption of these peptides to liquid-vapor interfaces. The adsorption to model surfaces was studied using ESCA, radiometry, and concentration-dependent contact angles. ESCA and radiometry measured irreversible biomolecules adsorption whereas the contact angle method measured steady-state adsorption. Radiometric results were inconsistent with ESCA, possibly due to artifacts associated with protein radiolabeling.
 ...
PMID:Peptide, protein, and cellular interactions with self-assembled monolayer model surfaces. 811 33

We investigated the molecular mechanism(s) by which platelets adhere to an artificial surface exposed to plasma, using polystyrene microtiter plates pretreated with plasma. Washed platelets labelled with 51Cr were incubated with the plates under static conditions. Prostaglandin E1(PGE1) was added to the platelets to prevent platelet-platelet interactions. Adhesion required the presence of a divalent cation such as Mg++ or Ca++. Polyclonal anti-fibrinogen antibody inhibited adhesion by 70%. Polyclonal antibodies against fibronectin, vitronectin, von Willebrand's Factor, and the Fc portion of human IgG, had no effect on adhesion. Platelets adhered normally to a surface pretreated with plasma from a patient with severe von Willebrand's disease. No platelet adhesion occurred when the surface was pretreated with an afibrinogenemic plasma. Monoclonal antibodies against platelet membrane GPIIb-IIIa, potent inhibitors of ADP-induced fibrinogen binding to platelets, completely inhibited adhesion. Monoclonal antibodies against the GPIb alpha subunit and GPIc(VLA alpha 5) showed no inhibitory effects on adhesion. Platelets from a patient with Glanzmann's thrombasthenia (type I) did not adhere to the surface pretreated with normal plasma. These results suggest that plasma fibrinogen adsorbed onto the surface and that platelet membrane glycoprotein(GP)IIb-IIIa were responsible for adhesion in an activation-independent manner.
 ...
PMID:Evidence that plasma fibrinogen and platelet membrane GPIIb-IIIa are involved in the adhesion of platelets to an artificial surface exposed to plasma. 813 6

Interaction between Aspergillus fumigatus conidia and different proteins known to mediate the attachment of malignant tumor cells or microorganisms to the host tissues was studied in vitro. Flow cytometry using fluorescein isothiocyanate-conjugated fibrinogen confirmed that binding of human fibrinogen to the conidia was dose dependent and specific. Binding was inhibited by unlabeled fibrinogen and by basement membrane laminin. Moreover, the expression of fibrinogen receptors at the surfaces of conidia seemed to be related to the maturation of the conidia. Binding sites appeared to be located in the D domains of the fibrinogen molecule. However, the peptide sequence recognized by the fungus could not be identified but was different from the classical adhesive recognition sequences, RGDS and fibrinogen gamma-chain dodecapeptide. In addition, an assay of adherence to proteins immobilized onto microtiter plates allowed us to establish the role of these interactions in fungal adhesion. Conidia strongly adhered to human fibrinogen and to laminin but not to fibronectin. Adhesion to fibrinogen substrates was specific, since it was inhibited by soluble fibrinogen and by specific antibodies, and seemed to be mediated by the D domains of the molecule. Study of the adhesion of numerous strains or clinical isolates to various mammalian fibrinogens did not reveal any particular affinity of strains for some animal species. Finally, by cultivation of the fungus in the presence of 125I-human fibrinogen and analysis of the radiolabeled material bound to the surface of the fungus, we were able to specify the sequence of events allowing its installation within the host. The interactions identified here may play an important role in governing fungal adherence and host tissue invasion.
 ...
PMID:Specific interaction of Aspergillus fumigatus with fibrinogen and its role in cell adhesion. 818 38

Adherence of 18 staphylococcal strains to 13 types of uncoated plastic tubes made from 10 different plastic materials were investigated by binding of radiolabelled bacteria in phosphate-buffered saline for 2 h at 37 degrees C. The different materials could be divided into five groups based on their ability to bind staphylococci. Lowest adhesion was found for plasticised polyvinylchloride. Simple assays for the relative binding of peroxidase-labelled human IgG or fibrinogen did not predict the result of adhesion studies. Neither bacterial surface hydrophobicity measured in a two-phase partitioning assay, nor hydrophobicity of materials (wettability) as measured by their contact angles in water correlated with bacterial adhesion. Adhesion of staphylococci to certain plastic materials was greatly influenced by the method used for sterilisation of the material.
 ...
PMID:Attachment of staphylococci to different plastic tubes in vitro. 828 13

Adhesion of resting and stimulated platelets to immobilized fibrinogen (Fg) was characterized using various forms of Fg, receptor peptide mimics, and antibodies to glycoprotein (GP) IIb/IIIa and Fg. Resting platelets adhered to Fg, but to less than half the extent of the same platelets stimulated with epinephrine/ADP. The adhesion of resting and stimulated platelets to Fg was inhibited by a receptor peptide mimic (G13, a peptide corresponding to residues 300-312 of GPIIb), anti-GPIIb/IIIa antibodies, and a monoclonal antibody (4A5) against the carboxyl terminus of the gamma chain of Fg. The results presented here demonstrate that the alpha chain RGD platelet recognition sites are not required to mediate the adhesion of either stimulated or resting platelets to immobilized Fg. Although stimulated platelets can adhere extensively to monomeric Fg containing one functional gamma chain, resting platelets require bivalent Fg containing two functional gamma chains to mediate irreversible adhesion to Fg.
 ...
PMID:Characterization of adhesion of "resting" and stimulated platelets to fibrinogen and its fragments. 836 34

VCL, fragment Leu504 to Lys728 of von Willebrand factor (vWF) expressed in Escherichia coli, contains the glycoprotein (GP) Ib-binding domain of vWF. This fragment inhibited ristocetin-induced platelet aggregation with an IC50 of 0.2 mumol/L and botrocetin-induced platelet aggregation with an IC50 of 0.08 mumol/L. We studied the antiadhesive profile of VCL by adding it to blood that was circulated over various adhesive surfaces. VCL inhibited adhesion to endothelial cell matrix, which served as a model of the vessel wall. Maximal inhibition at a high shear rate of 1600 s-1 was stronger (60%) than at a low shear rate of 300 s-1 (40%). Half maximal inhibition was found to be 1.5 mumol/L at both shear rates. The role of various adhesive molecules was investigated in more detail by coating glass coverslips with collagen type I, laminin, fibronectin, or vWF. Fibrinogen was studied as well. Platelet adhesion to laminin and vWF was not inhibited by VCL. Adhesion to collagen, fibronectin, and fibrinogen was particularly inhibited at a high shear rate. VCL coated to a coverslip caused a concentration-dependent adhesion that was blocked by antibodies against GPIb, which block interaction with vWF. Binding studies showed a nonsaturable ristocetin binding of VCL to platelets that was blocked by vWF or inhibitory antibodies against GPIb. Binding to collagen was weak, and VCL did not inhibit binding of vWF at a 5000-fold excess. From these data, we conclude that VCL inhibits adhesion in all cases in which adhesion is vWF dependent by competing for vWF binding to activated GPIb. The lack of inhibition of adhesion to vWF as a single molecule may be explained by assuming that this adhesion is determined by interaction of nonactivated GPIb with vWF that has been changed in conformation by adsorption. Studies investigating thrombus formation on the connective tissue of an atherosclerotic plaque in a human coronary artery showed that VCL was able to partially prevent this thrombus formation. VCL may be of value in preventing adhesion and thrombus formation under conditions in which these processes are dependent on vWF.
 ...
PMID:Adhesion of blood platelets is inhibited by VCL, a recombinant fragment (leucine504 to lysine728) of von Willebrand factor. 854 28

Normal circulating platelets do not adhere to intact, undisturbed endothelium. Studies have shown, however, that platelets will adhere to virally infected or thrombin-stimulated human umbilical vein endothelial cells. Using a novel platelet/endothelial cell adhesion assay we studied the interaction of thrombin-activated platelets to human saphenous vein endothelial cells (HSVEC), and its mechanism(s). Biotinylated platelets were exposed to Hepes-Tyrode buffer, 10E5 or PAC-1 [monoclonal antibodies (Mabs) blocking GPIIb-IIIa], AK4 (Mab blocking P-selectin, 6D1 (Mab blocking vWf binding to GPIb), RGDS (small peptide blocking the fibrinogen binding site), or EDTA (dissociates GPIIb-IIIa complex) and then activated with thrombin. The platelets were subsequently exposed to thrombin-stimulated monolayer HSVEC. Phycoerythrin-streptavidin was added to the wells to fluorescently label the platelets, followed by formaldehyde fixation and washing to remove nonadherent platelets. Adhesion of platelets to HSVEC was assessed using a fluorescent multiwell plate reader. Antibodies which blocked the GPIIb-IIIa receptor and agents which competitively bound the receptor all significantly inhibited activated platelet adhesion to the activated HSVEC. We have found that thrombin significantly increases platelet/HSVEC adhesion, and this event is mediated via the integrin GPIIb-IIIa (fibrinogen receptor). These GPIIb-IIIa receptor blocking Mabs and RGDS may be useful adjuncts for improving patency following angiographic intervention and/or vein grafting in patients with high risk of thrombosis. The assay we have developed is a valuable and relatively simple method for assessing platelet/endothelial cell adhesion and activation.
 ...
PMID:Adhesion of activated platelets to venous endothelial cells is mediated via GPIIb/IIIa. 865 40

Fibrinogen is a ligand for Intercellular Adhesion Molecule-1 (ICAM-1), and enhances monocyte-endothelial cell interaction by coupling Mac-1 on monocytes to ICAM-1 on endothelial cells. We investigated the role of the cytoskeleton in fibrinogen binding to the human endothelial cell line EA.hy 926 using immunofluorescence techniques. In this cell line TNF alpha induced the simultaneous appearance of stress fibers and of ICAM-1, which was clustered predominantly on endothelial cell projections. Incubation of TNF alpha-stimulated endothelial cells with fibrinogen resulted in binding of fibrinogen to ICAM-1 on these cell projections. Disruption of the cytoskeleton by cytocholasin B abolished fibrinogen binding. Activation of protein kinase C with 12-O-tetradecanoyl phorbol-13-acetate resulted in simultaneous loss of both stress fibers and fibrinogen binding. These results suggest that a connection between ICAM-1 and the cytoskeleton results in clustering of ICAM-1 on cell projections, which is required for fibrinogen binding.
 ...
PMID:Fibrinogen binding to ICAM-1 on EA.hy 926 endothelial cells is dependent on an intact cytoskeleton. 871 99

Adhesion between monocytic and mesothelioma or pleural mesothelial cells influences stromal remodeling in pleural neoplasia. We found that cultured monocytic cells (U937) adhere to either human pleural mesothelioma (MS-1) or mesothelial (MeT5A) cells in vitro. 125I-fibrinogen bound specifically and saturably to either cell line, and specific fibrinogen binding increased upon stimulation of these cells with proinflammatory agents such as phorbol myristate (PMA), lipopolysaccharide (LPS) or tumor necrosis factor (TNF-alpha). We purified the fibrinogen receptor protein from a membrane fraction of MS-1 cells and identified it by immunoprecipitation as intercellular adhesion molecule (ICAM-1). Anti-ICAM-1 antibody or antisense oligonucleotides inhibited fibrinogen-mediated cell adhesion and binding of 125I-fibrinogen to mesothelioma or mesothelial cells. Cultured monocytic cells adhere to either mesothelioma or mesothelial cells, and the interaction is promoted by fibrinogen binding ICAM-1 at the cell surface. ICAM-1 is expressed by mesothelioma cells and CD 11b by macrophages in the fibrinous mesothelioma tumor stroma. The data suggest a common mechanism by which monocytic cells could adhere to either malignant mesothelioma cells or the mesothelial surface in pleural neoplasia.
 ...
PMID:Fibrinogen promotes adhesion of monocytic to human mesothelioma cells. 872 24


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>