scholarly journals Distribution of sialoglycoconjugates on the luminal surface of the endothelial cell in the fenestrated capillaries of the pancreas.

1985 ◽  
Vol 33 (5) ◽  
pp. 474-476 ◽  
Author(s):  
V Muresan ◽  
M C Constantinescu
Keyword(s):  
Endothelial Cell ◽  
Vascular Endothelium ◽  
Binding Sites ◽  
Sodium Periodate ◽  
Luminal Surface ◽  
Nonspecific Binding ◽  
Coated Pits ◽  
Neuraminidase Treatment ◽  
Plasmalemmal Vesicles ◽  
Endothelial Surface

Sialic acid-bearing molecules on the luminal surface of the vascular endothelium in mouse and rat pancreatic capillaries were detected electron microscopically by using a procedure with ferritin hydrazide (FH), after preferential oxidation of sialyl residues with sodium periodate. The distribution of FH on the endothelial surface demonstrated the existence of microdomains with various densities of sialoglycoconjugates oxidizable by sodium periodate and accessible to the tracer. On the plasmalemma proper, FH binding sites were heterogeneously distributed. Their concentration on various microdomains decreased as follows: plasmalemma proper greater than coated pits greater than stomal diaphragms of plasmalemmal vesicles and transendothelial channels, and fenestral diaphragms. The membrane of plasmalemmal vesicles and transendothelial channels was not labeled by FH. Nonspecific binding of FH to the nonoxidized endothelial surface or that oxidized after neuraminidase treatment was relatively low.

scholarly journals Anionized and cationized hemeundecapeptides as probes for cell surface charge and permeability studies: differentiated labeling of endothelial plasmalemmal vesicles.

1985 ◽  
Vol 100 (2) ◽  
pp. 606-612 ◽  
Author(s):  
N Ghinea ◽  
N Simionescu
Keyword(s):  
Cell Surface ◽  
Capillary Endothelium ◽  
Luminal Surface ◽  
Amino Groups ◽  
Coated Pits ◽  
Plasmalemmal Vesicles ◽  
Peroxidatic Activity ◽  
Acidic Residues ◽  
Tertiary Amino ◽  
A Charge

To obtain small membrane markers easily accessible to the charged groups of the cell surface, we prepared, from hemeundecapeptide (HUP), three derivatives that maintain the peroxidatic activity: the anionized hemeundecapeptide, Mr 1,963, estimated diameter 1.68 nm, pl 3.5, for the detection of basic groups; and both a cationized hemeundecapeptide containing predominantly tertiary amino groups, Mr 2,215, estimated diameter 1.75 nm, pl 9.0, and a cationized hemeundecapeptide containing only primary amino groups, Mr 2,271, estimated diameter 1.75 nm, pl 10.6, for labeling acidic residues. The markers were perfused in situ in mice to label the luminal surface of fenestrated endothelium of pancreatic capillaries. Specimens were processed through the cytochemical reaction for peroxidatic activity and examined by electron microscopy. The anionized HUP and HUP (pl 4.85) marked the plasmalemma proper, the coated pits, and the membrane and diaphragms of plasmalemmal vesicles and transendothelial channels. The cationized HUP containing predominantly tertiary amino groups (pl 9.0) decorated all cell surface components with the exception of plasmalemmal vesicles and channels; the latter were, however, labeled by the cationized HUP containing only primary groups (pl 10.6), which suggests that these structures contain on their luminal surface very weak acidic residues of high pKa values. The fact that the membrane of plasmalemmal vesicles can discriminate against permeant cationic macromolecules only up to a pl of approximately 9.0 indicates that in the electrostatic restriction there is a charge limit. In the case of fenestrated capillary endothelium, the upper charge limit seems to be a pl of approximately 9.0. In these vessels, the charge discrimination is effective for molecules as small as 2 nm.

Cytochemical Specializations on the Luminal Surface of Blood Vessels in the Developing Rat Central Nervous System

1975 ◽  
Vol 33 ◽  
pp. 462-463
Author(s):  
R. S. Hannah ◽  
T. H. Rosenquist
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Blood Vessels ◽  
Alcian Blue ◽  
Luminal Surface ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Concentration Method ◽  
Endothelial Surface ◽  
Cacodylate Buffer

Developing blood vessels in the rat central nervous system exhibit several unusual luminal features. Hannah (1975) used high voltage electron microscopy to demonstrate numerous ridges of endothelium, some near junctional complexes. The ridges produced troughs (which may appear as depressions) in the endothelial surface. In some areas ridges extended over the troughs, removing them from direct contact with the luminal surface. At no time were the troughs observed to penetrate the basal laminae. Fingerlike projections also extended into the lumina.To determine whether any chemical specializations accompanied the unusual morphological features of the luminal surface, we added 0.1% Alcian blue (Behnke and Zelander, 1970) to the 3% glutaraldehyde perfusate (cacodylate buffer, pH 7.4). After Alcian blue had reacted with the luminal glycocalyces, the dye was dissociated with MgCl2 via critical electrolyte concentration method of Scott and Dorling (1965). When these methods are applied together, it is possible to differentiate mucopolysaccharides (glycosaminoglycans or GAG) with the electron microscope.

scholarly journals The Role of Putative Fibrinogen Aα-, Bβ-, and γA-chain Integrin Binding Sites in Endothelial Cell-mediated Clot Retraction

1997 ◽  
Vol 272 (35) ◽  
pp. 22080-22085 ◽  
Author(s):  
Richard A. Smith ◽  
M. W. Mosesson ◽  
Michael M. Rooney ◽  
Susan T. Lord ◽  
A.U. Daniels ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Binding Sites ◽  
Clot Retraction

Eliminating Nonspecific Binding Sites for Highly Reliable Immunoassay via Super-resolution Multicolor Fluorescence Colocalization

Nanoscale ◽  
2021 ◽  
Author(s):  
Shenfei Zong ◽  
Yun Liu ◽  
Kuo Yang ◽  
Zhaoyan Yang ◽  
Zhuyuan Wang ◽  
...  
Keyword(s):  
Binding Sites ◽  
Super Resolution ◽  
Specific Adsorption ◽  
Nonspecific Binding ◽  
Nonspecific Adsorption ◽  
Multicolor Fluorescence

Non-specific adsorption in immunoassays has always been a major problem that affects the reliability of assay results. Despite the emergence of various methods which can reduce nonspecific adsorption, a universal...

Glycosylation of developing human glomeruli: lectin binding sites during cell induction and maturation.

1987 ◽  
Vol 35 (1) ◽  
pp. 33-37 ◽  
Author(s):  
H Holthöfer ◽  
I Virtanen
Keyword(s):  
Binding Sites ◽  
Mesangial Cells ◽  
Ricinus Communis ◽  
Lectin Binding ◽  
Helix Pomatia ◽  
Cell Types ◽  
Basement Membranes ◽  
Phenotypic Change ◽  
Neuraminidase Treatment ◽  
Nephron Development

Expression of cellular glycoconjugates during differentiation of human fetal kidney was studied using fluorochrome-labeled lectins. Each lectin revealed a characteristic binding pattern during the phenotypic change of the nephrogenic mesenchyme and during distinct stages of nephron development. The uninduced mesenchymal cells were positive for Pisum sativum (PSA), Concanavalin A (ConA), Wistaria floribunda (WGA), and Ricinus communis (RCA-I) lectins. However, these lectins failed to react with the uninduced cells of the S-shaped bodies, whereas Maclura pomifera (MPA), Triticum vulgaris (WGA) and, after neuraminidase treatment, Arachis hypogaea (PNA) agglutinins bound intensely to the presumptive podocytes. During later stages of nephrogenesis, MPA positively on the podocytes weakened and could not be observed in adult kidney glomeruli. Binding sites for Helix pomatia (HPA) agglutinin in glomeruli were also expressed only transiently during nephrogenesis. During further development PSA, ConA, WFA, and RCA-I reacted with mesangial cells in addition to the glomerular basement membranes. The segment-specific lectin binding patterns of the tubuli emerged in parallel with the appearance of brush border and Tamm-Horsfall antigens of the proximal and distal tubuli. The results show that nephron site-specific saccharides appear in a developmentally regulated manner and in parallel with morphologic maturation of the nephron. Lectins therefore appear to be useful tools for study of induction and maturation of various nephron cell types.

scholarly journals Identification of the Protein C/Activated Protein C Binding Sites on the Endothelial Cell Protein C Receptor

2000 ◽  
Vol 276 (11) ◽  
pp. 8364-8370 ◽  
Author(s):  
Patricia C. Y. Liaw ◽  
Timothy Mather ◽  
Natalia Oganesyan ◽  
Gary L. Ferrell ◽  
Charles T. Esmon
Keyword(s):  
Endothelial Cell ◽  
Binding Sites ◽  
Protein C ◽  
Activated Protein C ◽  
Cell Protein

scholarly journals STUDIES ON ENDOTHELIAL REACTIONS

1920 ◽  
Vol 32 (5) ◽  
pp. 533-546 ◽  
Author(s):  
Nathan Chandler Foot
Keyword(s):  
Endothelial Cell ◽  
Vascular Endothelium ◽  
Colloidal Suspension ◽  
Giant Cells ◽  
Epithelioid Cell ◽  
Normal Lung ◽  
Capillary Endothelium ◽  
Alveolar Wall ◽  
Living Animal ◽  
Capillary Walls

1. The injection of a colloidal suspension, or sol, of carbon into the veins of a living animal, as recommended by McJunkin, furnishes an apparently reliable means of tracing the so called epithelioid cell of the pulmonary tubercle from its origin in the vascular endothelium to the lesion. 2. Experimental tubercles are formed in the lung, as in the liver, primarily by cells originating in the capillary endothelium. These cells are probably present in small numbers in the normal lung, lying free both in the alveolar wall and the air vesicles. In response to infection they proliferate in the capillary walls in the vicinity of the invading organisms, migrate in steadily increasing numbers, and, arriving at the site of the infection, further multiply and to some extent fuse to form the syncytia known as giant cells. 3. The epithelial cell takes no active part in the process; its proliferation tends to repair denuded surfaces and is regenerative rather than combative or phagocytic in nature. This cell is free from carbon and stains only diffusely with carmine, in contradistinction to the endothelial cell which readily takes up both pigments in granular form. 4. The cells of endothelial origin not only phagocytose tubercle bacilli, but carry them into the tissues, for example into lymph nodes, by way of the lymphatics, or into other lung lobules by way of the air passages, in which they are readily demonstrable.

scholarly journals Surface charge distribution on the endothelial cell of liver sinusoids.

1984 ◽  
Vol 99 (2) ◽  
pp. 639-647 ◽  
Author(s):  
L Ghitescu ◽  
A Fixman
Keyword(s):  
Endothelial Cell ◽  
Cell Surface ◽  
Liver Sinusoid ◽  
Electron Microscopic ◽  
Coated Pits ◽  
Endothelial Cell Surface ◽  
Liver Sinusoids ◽  
Surface Charge Distribution ◽  
Cationic Residues

The topography of the charged residues on the endothelial cell surface of liver sinusoid capillaries was investigated by using electron microscopic tracers of different size and charge. The tracers used were native ferritin (pl 4.2-4.7) and its cationized (pl 8.4) and anionized (pl 3.7) derivatives, BSA coupled to colloidal gold (pl of the complex 5.1), hemeundecapeptide (pl 4.85), and alcian blue (pl greater than 10). The tracers were either injected in vivo or perfused in situ through the portal vein of the mouse liver. In some experiments, two tracers of opposite charge were sequentially perfused with extensive washing in between. The liver was processed for electron microscopy and the binding pattern of the injected markers was recorded. The electrostatic nature of the tracer binding was assessed by perfusion with high ionic strength solutions, by aldehyde quenching of the plasma membrane basic residues, and by substituting the cell surface acidic moieties with positively charged groups. Results indicate that the endothelial cells of the liver sinusoids expose on their surface both cationic and anionic residues. The density distribution of these charged groups on the cell surface is different. While the negative charge is randomly and patchily scattered all over the membrane, the cationic residues seem to be accumulated in coated pits. The charged groups co-exist in the same coated pit and bind the opposite charged macromolecule. It appears that the fixed positive and negative charges of the coated pit glycocalyx are mainly segregated in space. The layer of basic residues is located at 20-30-nm distance of the membrane, while most of the negative charges lie close to the external leaflet of the plasmalemma.

Involvement of Ca2+ in the H2O2-induced increase in endothelial permeability

1996 ◽  
Vol 270 (6) ◽  
pp. L973-L978 ◽  
Author(s):  
A. Siflinger-Birnboim ◽  
H. Lum ◽  
P. J. Del Vecchio ◽  
A. B. Malik
Keyword(s):  
Hydrogen Peroxide ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Binding Sites ◽  
Endothelial Permeability ◽  
Extracellular Medium ◽  
Critical Determinant ◽  
Cell Monolayers ◽  
Sensitive Membrane

We studied the role of Ca2+ in mediating the hydrogen peroxide (H2O2)-induced increase in endothelial permeability to 125I-labeled albumin using bovine pulmonary microvessel endothelial cells (BMVEC). Changes in cytosolic-free Ca2+ ([Ca2+]i) were monitored in BMVEC monolayers loaded with the Ca(2+)-sensitive membrane permeant fluorescent dye fura 2-AM. H2O2 (100 microM) produced a rise in [Ca2+]i within 10 s that was reduced by the addition of EGTA to the medium. Uptake of 45Ca2+ from the extracellular medium increased in the presence of H2O2 (100 microM) compared with control monolayers, suggesting that the H2O2-induced rise in [Ca2+]i is partly the result of extracellular Ca2+ influx. The effects of [Ca2+]i on endothelial permeability were addressed by pretreatment of BMVEC monolayers with BAPTA-AM (3-5 microM), a membrane permeant Ca2+ chelator, before the H2O2 exposure. BAPTA-AM produced an approximately 50% decrease in the H2O2-induced increase in endothelial permeability compared with endothelial cell monolayers exposed to H2O2 alone. The increase in endothelial permeability was independent of Ca2+ influx, since LaCl3 (0-100 microM), which displaces Ca2+ from binding sites on the cell surface, did not modify the permeability response. These results indicate that the rise in [Ca2+]i produced by H2O2 is a critical determinant of the increase in endothelial permeability.

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