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

Prostacyclin (1 ng to 2 micrograms per ml), which effectively inhibits platelet secretion and aggregation, does not affect adhesion of a proportion of platelets (10-38%) to collagen (50-100 micrograms/ml). Adhesion is not detectable by changes of light transmission (as measured in the optical aggregometer) and is not affected by inhibitors of cyclooxygenase and lipoxygenase enzymes such as indomethacin and compound BW 755C. This adhesion is independent of the collagen concentration (50-400 micrograms/ml) and the incubation time (5-20 min). This suggests that adhesion to collagen is related to a specific platelet population. Adhesion in the presence of prostacyclin, indomethacin and BW 755C occurs in parallel with the formation of a limited amount of phosphatidic acid. Under those conditions it is also possible to observe some phosphorylation of a 40,000 dalton protein which is a substrate for protein kinase C activity. Phosphorylation of the 20,000 dalton protein, or myosin light chain, is less evident. Chlorpromazine (25-100 micrograms/ml) inhibited the adhesion of platelets to collagen, but propanolol (0.5-4 microM) was inactive. The adhesion of platelets to collagen in these experiments parallels the formation of a fraction of phosphatidic acid and 40,000 dalton protein phosphorylation, which are independent of the increased levels of platelet cyclic-AMP induced by high concentrations of prostacyclin. It is also independent of the formation of cyclooxygenase or lipoxygenase products.
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PMID:Adhesion of human platelets to collagen in the presence of prostacyclin, indomethacin and compound BW 755C. 308 71

Single cell suspensions of early postnatal mouse cerebellum adhere to substrate-bound culture supernatants of the teratocarcinoma cell line PF-HR9 and can be inhibited to adhere by antibodies to the neural cell adhesion molecules L1 and N-CAM. Adhesion can also be inhibited by the glycosaminoglycans heparin and heparan sulfate, and less by chondroitin sulfate or hyaluronic acid. Heparinase treatment of cells, but not of HR9 substrate, reduces adhesion. Adhesion does not appear to be mediated by laminin, a constituent of HR9 extracellular matrix, since L1 and N-CAM antibodies do not interfere with cell adhesion on EHS sarcoma laminin as substrate and since antibodies to EHS sarcoma laminin partially inhibit adhesion to HR9 extracellular matrix which contains laminin. Of the other extracellular matrix constituents analysed in HR9 culture supernatants (collagen type IV, a heparan sulfate proteoglycan and fibronectin) none could be shown to promote adhesion, when coated as substrate, suggesting that yet unidentified compounds are responsible for L1- or N-CAM-mediated cell adhesion. These experiments show for the first time that extracellular matrix constituents can act as binding partners for the neural cell adhesion molecules L1 and N-CAM.
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PMID:Adhesion of neural cells to extracellular matrix constituents. Involvement of glycosaminoglycans and cell adhesion molecules. 317 50

To evaluate the effect of substratum on corneal epithelial cell growth and on protein synthesis, bacteriological dishes were coated with laminin, fibronectin, Type I collagen or Type IV collagen. Cell growth was enhanced by day 6 on both laminin and Type I collagen substrata. Adhesion sites and parallel microfilament arrays were present only on cells cultured on laminin coated substratum. The synthesis of connective tissue and cytoskeletal proteins was influenced by the four different substrata. Both the time course and the amount synthesized was affected. The results of this study indicate that the substratum plays a significant role in regulating the synthesis of specific proteins.
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PMID:Influence of substratum on corneal epithelial cell growth and protein synthesis. 319 69

Platelet adhesion was tested ex vivo in a group of 7 normal individuals on varying doses of vitamin E. Adhesion to glass slides coated with fibrinogen, fibronectin, collagen I and collagen V was studied by perfusing platelet-rich plasma through a flow chamber. Time- and space-resolved observations of platelet adhesion were made in an area of parallel flow lines and low shear rate under standardized conditions before and after dietary supplementation with vitamin E. The doses varied from 400 I.U./day to 1600 I.U./day in 400 I.U. increments. A statistically significant reduction in platelet adhesion was noted on all four adhesive surfaces at the 400 I.U. level of vitamin E supplementation. This reduction varied in magnitude depending on the adhesive surface. As vitamin E supplementation was increased, no dose-dependent downward trend in adhesion rate was observed although the platelet alpha-tocopherol content progressively increased. Based on our results, we suggest that 400 I.U./day may be a near optimal dose of vitamin E to reduce platelet adhesivity as evaluated in our flow chamber system.
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PMID:Reduction of platelet adhesiveness by vitamin E supplementation in humans. 338 Nov 98

Freshly isolated bone cells from embryonic chick calvariae were found to attach to films of native monomeric type I or II collagen, to gels of native type I collagen and, to a lesser extent, to air-dried films of these collagens, in a fibronectin-independent manner, and with no requirement for collagen synthesis. Adhesion to type III collagen was relatively poor. Films of native monomeric type I or II collagen were preferred to the corresponding air-dried films as substrata for proliferation. Cis-hydroxyproline inhibited growth upon both plastic and type I and type II collagenous substrata, but this effect could largely be overcome by providing bone cell-conditioned medium, suggesting the possibility of a requirement in the growth process for synthesis of a collagen other than type I, the major form in bone matrix.
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PMID:Interaction of embryonic chick calvarial bone cells with collagen substrata; attachment characteristics and growth behaviour. 338 71

Adhesion of bovine endothelial cells on fibronectin and collagen before and after nonenzymatic glycation in vitro has been studied. Nonenzymatic glycation of these proteins reduced their ability to bind endothelial cells. Furthermore, nonenzymatically glycated fibronectin failed to bind to normal and nonenzymatically glycated gelatin and to fibrin. So gelatin and fibrin Sepharoses can be used to separate highly glycated fibronectins from fibronectins with a low degree of nonenzymatic glucose substitution. Sodium dodecylsulfate polyacrylamide gel electrophoresis did not demonstrate a covalent cross-link between nonenzymatically glycated fibronectins. These results present further evidences for the role of nonenzymatic glycation of proteins in the development of vascular complications in long-term diabetes and of atherosclerosis.
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PMID:Diminished adhesion of endothelial aortic cells on fibronectin and collagen layers after nonenzymatic glycation. 340 68

In the present study we show that adhesion of normal rat liver epithelial cells (RL34) to substratum coated with type I collagen (collagen substratum) is promoted by a factor involved in 80% ammonium sulfate precipitated proteins from serum-free conditioned medium (PCM) of rat embryo fibroblasts. Adhesion of RL34 cells to collagen substratum was promoted dose dependently by whole PCM and the maximum effects on adhesion could be achieved by 200 micrograms/ml whole PCM. Kinetics studies with 100 micrograms/ml whole PCM showed that adhesion proceeded very slowly, taking 16 h to reach a plateau. Adhesion-promoting activity in whole PCM was sensitive to treatments with trypsin, acid, and heat but stable to dithiothreitol treatment. Further purification of whole PCM was performed using a combination of chromatography on blue Sepharose column, gel filtration column and heparin Sepharose column. The partially purified proteins, referred to as heparin PCM, are not bound or only weakly bound to heparin under physiological ion strength and pH, and the apparent molecular weight (Mr) range is estimated to be 40,000 to 60,000 from gel filtration chromatography and SDS-polyacrylamide gel electrophoresis. When whole PCM or heparin PCM was used for coating on plastic or collagen substratum, they no longer exerted the promoting activity.
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PMID:Adhesion-promoting factor from embryonic fibroblasts for normal liver epithelial cells. 359 33

Adhesion of rat blood platelets to native rat tail collagen fibrils was studied in the electron microscope under conditions that preserved collagen-associated proteoglycans (CAPG). The CAPG molecules were aligned in chain-like configurations that encircled the fibrils with a 65 nm period; they appeared to coat the fibrils completely and extended 60-100 nm away from the fibril. The initial platelet-fibril contact occurred between the platelet glycocalyx and the CAPG of the fibrils i.e. between two surfaces with net-negative charges. When close contact was established between the fibril surface proper and the platelet membrane, CAPG were not identified in the area of contact, and the collagen-platelet distance was reduced to a approximately 10-12 nm wide gap traversed by delicate links in register with fibril periodicities.
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PMID:Platelet adhesion to native collagens involves proteoglycans and may be a two-step process. 367 30

Platelet adhesion to monomeric collagen types I and III, which were purified from human umbilical arteries, was studied in a perfusion chamber under well defined flow conditions. For this purpose, glass coverslips were coated with 20-30 micrograms/cm2 of collagen types I and III by spraying a solution of these collagens with a retouching air brush. Platelet deposition increased with the time of perfusion. Adhesion to both collagen types was similar in the first 3 min, but increased platelet deposition occurred on collagen type III after 3 min due to thrombus formation. Adhesion at a shear rate of 800 s-1 was strongly impaired with plasma of a patient with von Willebrand's disease or with fibronectin-free plasma. Addition of purified fibronectin to fibronectin-free plasma restored adhesion to the level obtained with normal plasma. Platelet deposition in normal plasma increased with increasing shear rates. Platelet deposition in VWD-plasma was normal at 490 s-1, but there was no increase at higher shear rates. Platelet deposition in fibronectin-free plasma was diminished at all shear rates studied from 490 to 1,300 s-1. Perfusion with a human albumin solution (HAS) to which purified Factor VIII-von Willebrand factor complex (FVIII-VWF) and fibronectin had been added gave similar platelet deposition as with normal plasma. Preincubation of collagen with FVIII-VWF and perfusion with HAS containing fibronectin, or, conversely, preincubation with fibronectin and perfusion with HAS containing FVIII-VWF, also resulted in adhesion similar to that observed in normal plasma. Similar adhesion was also observed after preincubation with both FVIII-VWF and fibronectin and subsequent perfusion with HAS alone. Sequential preincubations with first FVIII-VWF and then fibronectin, or with first fibronectin and then FVIII-VWF followed by perfusion with HAS, also gave a similar adhesion as observed with normal plasma. These data indicate that platelet adhesion to monomeric collagen types I and III is dependent on both FVIII-VWF and fibronectin. FVIII-VWF is only required at relatively high shear rates; fibronectin also at relatively low shear rates. Their complementary role in platelet adhesion suggests separate binding sites for FVIII-VWF and fibronectin on collagen. Platelet deposition on performed fibrils of collagen types I and III was also studied. Initial adhesion expressed as percentage surface coverage was similar to that found with monomeric collagen, but thrombus formation was much enhanced. Adhesion on fibrillar collagen at 800 s(-1) was impaired in VWD-plasma and fibronectin-free plasma, and was restored by addition of purified fibronectin to fibronectin-free plasma. When perfusions were performed with HAS, only addition of FVIII-VWF was required for optimal adhesion to fibrillar collagen; addition of fibronectin had no effect. These data are in contrast to the studies with monomeric collagens described above, in which the addition of both FVIII-VWF and fibronectin was required. These data are also in contrast to the observation that in plasma both FVIII-VWF and fibronectin are required for optimal adhesion to fibrillar collagen.
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PMID:Role of factor VIII-von Willebrand factor and fibronectin in the interaction of platelets in flowing blood with monomeric and fibrillar human collagen types I and III. 391 60

Adhesion of hepatocytes to collagenous substrates and their spreading have been shown to involve a specific recognition event, possibly mediated by membrane proteins with affinity for collagen. In the present communication, we describe the isolation of membrane components that are involved in the adhesion of rat hepatocytes to collagen. These components could be solubilized from liver microsomal membranes by treatment with detergents or papain--but not by treatment with EDTA, urea or high salt. The purification of detergent-solubilized components was monitored by an assay determining the ability of membrane components to neutralize antibody-mediated inhibition of hepatocyte adhesion to collagen. By affinity chromatography on lentil lectin-Sepharose it was found that the neutralizing activity resided within the glycoprotein fraction. These glycoproteins were purified further by affinity-chromatography on collagen type I linked to Sepharose. Antibodies raised against the glycoproteins with affinity for immobilized collagen, effectively inhibited hepatocyte adhesion to collagen. The bulk of the neutralizing activity migrated with an apparent molecular weight of 120 000-140 000 in preparative SDS-PAGE.
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PMID:Hepatocyte adhesion to collagen. Isolation of membrane glycoproteins involved in adhesion to collagen. 395 90


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