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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 and dog platelets to native and collagen-coupled Cuprophan under defined flow conditions was studied by scanning and transmission electron microscopy. Dog platelets, singly adherent to and uniformly distributed on both native and collagen-coupled Cuprophan, extend slender pseudopods across the surface without evidence of degranulation. Human platelets, while not adhering to native Cuprophan, formed irregularly shaped, semi-confluent cytoplasmic sheets on the collagen-coupled surface. Extensive cytoplasmic reorganization and degranulation suggests a post-release state of the human platelets. Aspirin had no apparent effect on either human or dog platelet adhesion or upon the apparent release state of the human platelets.
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PMID:Ultrastructural characteristics of dog and human platelets adherent to native and collagen-coupled cuprophan. 53 1

To study platelet activation as a phenomenon that may precede development of angiopathy in diabetes mellitus, we compared platelet adhesion and thrombus formation in a flow system with blood from insulin-dependent (type I) diabetic subjects with and without macroangiopathy and age- and sex-matched control subjects. Adhesion and thrombus formation on matrix of cultured human endothelial cells (ECM) and adhesion on matrix of human fibroblasts (FBM) were studied after exposure to flowing blood at shear rates of 300 and 1300 s-1 and exposure times of 1, 3, 5, and 10 min (and 20 min in adhesion experiments). Blood was anticoagulated with trisodium citrate (1:10 vol/vol, 110 mM) or low-molecular-weight heparin ([LMWH] 20 U/ml). Endothelial cell cultures were either unstimulated or stimulated with 4 beta-phorbol 12-myristate 13-acetate (PMA) 16 h before isolating their matrix. Platelet adhesion on ECM and FBM in citrated and LMWH-anticoagulated blood was identical in diabetic patients and control subjects, with comparable increases of adhesion with increasing perfusion times. Platelet aggregate formation on ECM of PMA-stimulated cells with LMWH-anticoagulated blood was similar in diabetic patients, whether macroangiopathy was present, compared with control subjects. Fibrin deposition and fibrinopeptide A generation during perfusion were comparable in diabetic and control subjects. Platelet thromboxane B2 formation after stimulation with arachidonic acid was increased in diabetic patients without macroangiopathy compared with age- and sex-matched control subjects. In the perfusion system, the patterns of platelet adhesion and aggregate formation on extracellular matrix in flowing blood of diabetic patients (with or without macroangiopathy), and healthy age- and sex-matched control subjects followed a similar pattern.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet adhesion and aggregate formation in type I diabetes under flow conditions. 193 2

Cells of the rat neuronal line, PC12, adhere well to substrates coated with laminin and type IV collagen, but attach poorly to fibronectin. Adhesion and neurite extension in response to these extracellular matrix proteins are inhibited by Fab fragments of an antiserum (anti-ECMR) that recognizes PC12 cell surface integrin subunits of Mr 120,000, 140,000, and 180,000 (Tomaselli, K. J., C. H. Damsky, and L. F. Reichardt. 1987. J. Cell Biol. 105:2347-2358). Here we extend our study of integrin structure and function in PC12 cells using integrin subunit-specific antibodies prepared against synthetic peptides corresponding to the cytoplasmic domains of the human integrin beta 1 and the fibronectin receptor alpha (alpha FN) subunits. Anti-integrin beta 1 immunoprecipitated a 120-kD beta 1 subunit and two noncovalently associated integrin alpha subunits of 140 and 180 kD from detergent extracts of surface-labeled PC12 cells. Immunodepletion studies using anti-integrin beta 1 demonstrated that these two putative alpha/beta heterodimers are identical to those recognized by the adhesion-perturbing ECMR antiserum. Anti-alpha FN immunoprecipitated fibronectin receptor heterodimers in human and rat fibroblastic cells, but not in PC12 cells. Thus, low levels of expression of the integrin alpha FN subunit can explain the poor attachment of PC12 cells to FN. The PC12 cell integrins were purified using a combination of lectin and ECMR antibody affinity chromatography. The purified integrins: (a) completely neutralize the ability of the anti-ECMR serum to inhibit PC12 cell adhesion to laminin and collagen IV; (b) have hydrodynamic properties that are very similar to those of previously characterized integrin alpha/beta heterodimeric receptors for ECM proteins; and (c) can be incorporated into phosphatidylcholine vesicles that then bind specifically to substrates coated with laminin or collagen IV but not fibronectin. Thus, the ligand-binding specificity of the liposomes containing the purified PC12 integrins closely parallels the substrate-binding preference of intact PC12 cells. These results demonstrate that mammalian integrins purified from a neuronal cell line can, when incorporated into lipid vesicles, function as receptors for laminin and type IV collagen.
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PMID:Purification and characterization of mammalian integrins expressed by a rat neuronal cell line (PC12): evidence that they function as alpha/beta heterodimeric receptors for laminin and type IV collagen. 284 50

In order to determine whether the phenomenon of sickle erythrocyte adherence to cultured vascular endothelium exists under conditions of blood flow, we exposed monolayers of bovine aortic endothelial cells to flowing sickle cell blood under controlled conditions in a specially designed flow chamber. Individual red cells were imaged by means of epifluorescent videomicroscopy, five percent of the total number of red cells in an aliquot of blood having been labelled by the passive uptake of sodium fluorescein isothiocyanate. At a shear rate of 270 sec-1 at the blood-monolayer interface, red cells from sickle cell blood frequently adhered to the monolayer for periods ranging from 100's of m sec to greater than 30 sec. With adhesion defined as the average number of adherent red cells during the sixth minute of blood flow (corrected upward to account for unlabelled erythrocytes), adhesion with sickle cell blood was of the order of 10(4) erythrocytes/cm2 ECM and exceeded (p less than 0.001) that for normal blood by a factor of 5.6. Further studies utilizing in situ displacement of blood with culture medium followed by brightfield microscopy indicate that the adherent cells were predominantly discocytes having single points of tethering to unknown sites on the monolayer. Adhesion of sickle cell erythrocytes to endothelium, therefore, is a very real phenomenon under physiologic conditions of blood flow; this phenomenon may contribute to the pathophysiology of vaso-occlusive events seen in sickle cell disease.
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PMID:Sickle erythrocytes adhere to endothelial cell monolayers (ECM's) exposed to flowing blood. 361 85

As decided in the protocol, the AICLA study ended when all the 604 patients had completed a follow up of three years. Adhesion to the protocol and drug compliance were excellent. Side effects, particularly peptic ulcers and bleedings of various origins were more frequent in the 2 treatment groups containing aspirin. The number of fatal and non fatal cerebral infarction was 31 in the P group, 17 in the ASA group, and 18 in the ASA + D group. Taking into account the duration of follow up for each patient, these figures correspond to cummulate rates of 18 p. 100 in the P group and 10.5 p. 100 in the 2 others. Analysis with the Mantel Method showed: 1 - a difference at the 6 p. 100 level between the 3 groups and between P an AD; 2 - A difference at the 5 p. 100 level between P and A; 3 - No difference between A and AD; 4 - A difference at the 2 p. 100 level between the P group and the two treated groups taken together. Among other diseases occurring during the trial, the only significant difference concerned myocardial infarction, less frequent in the 2 treated groups (p less than 0.05). Subgroup analysis failed to show a significant sex difference in the efficacy of aspirin. It is concluded that, in patients such as those defined in the protocol, Aspirin (1 g) has a significant beneficial effect in the secondary prevention of atherothrombotic cerebral infarction.
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PMID:[The A.I.C.L.A. controlled cooperative trial. Secondary prevention of cerebral ischemic accidents due to atherosclerosis by aspirin and dipyridamole. 3: Results]. 635 Dec 16

Adhesion of polymorphonuclear granulocytes (PMN) to extracellular matrix proteins has been shown to be important for their migration in vitro and is thought to participate in PMN recruitment to sites of inflammation. Isolated human PMN stimulated with PMA were found to adhere best to microtiter wells coated with the novel ECM glycoprotein undulin (27 +/- 3% of PMNs added), followed by fibrinogen (25 +/- 2%), collagen type VI (18 +/- 2%), fibronectin (16 +/- 2%), and laminin (15 +/- 3%). PMN adhesion to other collagens ranged between 3 and 11%. Monoclonal antibodies recognizing CD18 and CD11b subunits of Mac-1 inhibited adhesion of PMN to collagens by an order of magnitude more effectively than to all noncollagenous substrates. F(ab')2 fragments of the anti-CD18 antibody were also able to block adhesion to collagens. Anti-LFA-1 (CD11a) and anti-CD44 antibodies did not significantly reduce adhesion. PMN adhesion was also inhibited by soluble collagens type II and VI (ID50 approximately 75 micrograms/ml). Binding of soluble radiolabeled collagens type II and VI to PMNs was specific and saturable with apparent dissociation constants of 2.2 and 1.9 nM, respectively, and specific binding of collagens type II and VI was almost completely inhibited by anti-CD18, but not by control antibodies. These data indicate that Mac-1 function is required for binding of human PMN to collagens.
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PMID:The leukocyte integrin Mac-1 (CD11b/CD18) contributes to binding of human granulocytes to collagen. 773 65

Integrins play a major role in cell-matrix interactions. They alter cellular functions upon binding to matrix proteins or following cross linking and can in turn be regulated by other stimuli acting on the cell. In the kidney integrins may help regulate cellular proliferation and matrix turnover during renal injury, effects which could play an important role in the pathogenesis of glomerulosclerosis and the resultant loss of renal function. Alterations in cell adhesiveness may contribute to tubular epithelial cell sloughing and tubular obstruction in acute renal failure and may play a role in alterations of glomerular capillary wall permeability, leading to proteinuria. Adhesion molecules on GEC may be important targets of antibodies in several models of proteinuric renal disease and areas of GEC detachment from the GBM may be involved in the development of glomerulosclerosis. Since integrins are major links between the ECM and cells, better understanding of their function in the normal kidney and during injury is of importance to a better understanding of the pathogenesis of renal disease.
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PMID:Integrin matrix receptors in renal injury. 815 6

A variety of cell adhesion mechanisms underlie the way that cells are organized in tissues. Stable cell interactions are needed to maintain the structural integrity of tissues, and dynamic changes in cell adhesion participate in the morphogenesis of developing tissues. Stable interactions actually require active adhesion mechanisms that are very similar to those involved in tissue dynamics. Adhesion mechanisms are highly regulated during tissue morphogenesis and are intimately related to the processes of cell motility and cell migration. In particular, the cadherins and the integrins have been implicated in the control of cell movement. Cadherin mediated cell compaction and cellular rearrangements may be analogous to integrin-mediated cell spreading and motility on the ECM. Regulation of cell adhesion can occur at several levels, including affinity modulation, clustering, and coordinated interactions with the actin cytoskeleton. Structural studies have begun to provide a picture of how the binding properties of adhesion receptors themselves might be regulated. However, regulation of tissue morphogenesis requires complex interactions between the adhesion receptors, the cytoskeleton, and networks of signaling pathways. Signals generated locally by the adhesion receptors themselves are involved in the regulation of cell adhesion. These regulatory pathways are also influenced by extrinsic signals arising from the classic growth factor receptors. Furthermore, signals generated locally be adhesion junctions can interact with classic signal transduction pathways to help control cell growth and differentiation. This coupling between physical adhesion and developmental signaling provides a mechanism to tightly integrate physical aspects of tissue morphogenesis with cell growth and differentiation, a coordination that is essential to achieve the intricate patterns of cells in tissues.
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PMID:Cell adhesion: the molecular basis of tissue architecture and morphogenesis. 860 88

Adhesion molecules of the integrin family, including very late activation antigens (VLA), have been implicated in various cellular functions. In this study, we investigated the contribution of integrin-mediated interaction with ECM proteins to the cytokine gene expression in human chondrocytes. Human articular chondrocytes expressed VLA-1, -2, -3 and -5 on the cell surface, and could adhere to various ECM proteins, especially to fibronectin (FN). Furthermore, the production of GM-CSF and IL-6 was potently induced by culturing chondrocytes on immobilized FN. This stimulative effect of FN was completely inhibited by an anti-integrin alpha 5 chain mAb, as well as by anti-integrin beta 1 chain mAbs. These results indicate an important role of the VLA-5-mediated interaction with FN in regulating inflammatory cytokine production by human articular chondrocytes.
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PMID:VLA-5-mediated interaction with fibronectin induces cytokine production by human chondrocytes. 861 19

Laminin (Ln) isoforms may play important roles in neuronal development, particularly axon guidance, but neural receptors mediating interactions with Ln are not entirely understood. In this paper, we have compared the adhesive and process outgrowth activities of a human neuroblastoma cell line SY5Y on various laminin isoforms. Cell adhesion and process outgrowth were examined on murine Ln-1 (Englebreth-Holm-Swarm sarcoma laminin), human placental Ln-1 (human Ln-1[p]), human Ln-2 (merosin), human Ln-5 (kalinin/epiligrin/nicein), and human foreskin keratinocyte extracellular matrix extract (human HFK-ECM). Ln-5 was shown to evoke process outgrowth in amounts comparable to other Ln isoforms. Antibody perturbation experiments showed that adhesion and process outgrowth on murine Ln-1 was primarily mediated by the integrin alpha 1 beta 1, whereas adhesion and outgrowth on human Ln-5 and human HFK-ECM were mediated by alpha 3 beta 1. Adhesion to human Ln-1(p) and Ln-2 was not blocked by addition of anti-alpha 1 or anti-alpha 3 antibodies alone, but adhesion was partially perturbed when these antibodies were added in combination. Process outgrowth on human Ln-1(p) was blocked when either anti-alpha 3 or anti-beta 1 antibodies were added, indicating that alpha 3 beta 1 is the primary integrin heterodimer responsible for process extension on this substrate. These results demonstrate that Ln-5 and other Ln isoforms support comparable levels of adhesion and process outgrowth, but different integrin heterodimers, alone and in combination, are used by SY5Y cells to mediate responses.
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PMID:Human SY5Y neuroblastoma cell interactions with laminin isoforms: neurite outgrowth on laminin-5 is mediated by integrin alpha 3 beta 1. 880 89


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