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

Adhesion of leukocytes and platelets to solid substrates of different surface tensions and hence different wettability is studied from a thermodynamic point of view. A simple thermodynamic model predicts that a cellular adhesion should increase with increasing surface tension of the solid substrate if the surface tension of the medium in which the cells are suspended is lower than the surface tension of the cells. If the surface tension of the suspending medium is higher than that of the cells, the opposite behavior is predicted. These predictions are borne out completely by neutrophil adhesion tests, where the surface tension of the aqueous suspending medium is varied by addition of dimethyl sulfoxide (DMSO). Platelet adhesion experiments also confirm these predictions, the only difference being that surface tensions of the suspending medium above that of the platelets cannot be realized, owing to exudation of surface active solutes from the platelets. Utilization of the thermodynamic prediction that cellular adhesion should become independent of the surface tension of the substrate when the surface tensions of the cells and that of the suspending medium are equal leads to a value of the surface tension of neutrophils of 69.0 erg/cm(2), in excellent agreement with the value obtained from contact angles measured on layers of cells.
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PMID:Surface thermodynamics of leukocyte and platelet adhesion to polymer surfaces. 9 70

We present a model for the calculation of intragranular vesicle adhesion energy in a two-vesicle system consisting of an external secretory vesicle (chromaffin granule) and an intragranular vesicle (IGV) that adheres from the inside to the granule membrane. The geometrical parameters characterizing the granule-IGV systems were derived from freeze-fracture electron micrographs. Adhesion is brought about by incubation of the granules in hyperosmolar sucrose solutions. It is accompanied by a deformation of the granule because the intragranular vesicle bulges it outwards, and by segregation of intramembraneous particles from the adherent part of the granule membrane. Adhesion prevents the deformed granules from osmotic reexpansion and, therefore, causes hyperosmotic relaxation lysis. We estimated specific adhesion energy at -3 erg/cm2, a value which is 10 - 1000 times larger than the energy of van der Waals interaction between membranes. This large interaction energy probably results from changes of the granule core induced by dehydration. A minimization of the interface between the granule core and adjacent membranes could exclude intragranular vesicles from the core and squeeze them towards the granule membrane. This might induce a new kind of interaction between both membranes, which is irreversible and causes lysis upon osmotic relaxation.
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PMID:On the interaction between chromaffin granule membranes and intragranular vesicles--theory and analysis of freeze-fracture micrographs. 204 34

In this paper, interfacial aspects of spreading and adhesion of human skin fibroblasts on solid substrata after protein precoating have been studied. Three solid substrata were used with different surface free energy (gamma s): Tissue Culture Polystyrene (TCPS) with gamma s = 70 erg.cm-2, Polyvinylfluoride (PVF) with gamma s = 56 erg.cm-2 and Fluoroethylenepropylene (FEP) copolymer with gamma s = 18 erg.cm-2. The substrata were precoated with fetal calf serum, bovine fibronectin or bovine serum albumin. Cell spreading was evaluated by means of light microscopy and scanning electron microscopy (SEM). Adhesion sites were studied by transmission electron microscopy (TEM). In general, spreading was lowest on FEP and highest on TCPS. Although protein precoating markedly increased cell spreading, the relative order in which the cells spread on the protein precoated substrata remained identical to that on the bare substrata. Analysis of the kinetics of spreading demonstrated that spreading was fastest on the high-energy substratum and slowest on the low-energy substratum. In the presence of all three types of protein precoating, the average distance between a cell and a substratum after spreading was smaller (20-50 nm) than without a coating (greater than 100 nm).
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PMID:Kinetics of cell spreading on protein precoated substrata: a study of interfacial aspects. 271 33