A new occludens-like junction linking endothelial cells of small capillaries (probably venules) of rat jejunum

1975 ◽  
Vol 18 (3) ◽  
pp. 545-551
Author(s):  
L.A. Staehelin
Keyword(s):  
Endothelial Cells ◽  
Tight Junctions ◽  
Plasma Membranes ◽  
Rat Jejunum ◽  
Focal Points ◽  
Zonulae Occludentes ◽  
Low Profile ◽  
New Type ◽  
Endothelial Junction ◽  
Small Venule

Freeze-cleave replicas of small capillaries of rat jejunum have revealed the presence of a new type of junction linking endothelial cells. This new junction reveals tight junctions (zonulae occludentes) in that the adjacent plasma membranes are held closely together along lines of attachment organized in the form of a loose, but frequently discontinuous network. In contrast to tight junctions, the A-face ridges possess a very low profile, and only at low shadowing angles can a repeating, particulate substructure occasionally be resolved. The shallow B-face furrows lack any particulate components. Images of cross-fractured focal points of attachment suggest that the external leaflets of adjacent membranes are closely apposed but not actually fused, as is the case with zonulae occludentes. It appears that this new type of endothelial junction is characteristic of small venules. Thus we propose that it be termed small venule endothelial junction.

scholarly journals HEXAGONAL ARRAY OF SUBUNITS IN TIGHT JUNCTIONS SEPARATED FROM ISOLATED RAT LIVER PLASMA MEMBRANES

1968 ◽  
Vol 38 (1) ◽  
pp. 15-24 ◽  
Author(s):  
E. L. Benedetti ◽  
P. Emmelot
Keyword(s):  
Tight Junctions ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Hexagonal Array ◽  
Structural Differentiation ◽  
Isolated Rat Liver ◽  
Zonulae Occludentes ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Isolated Rat

Solubilization of isolated rat liver plasma membranes in 1% deoxycholate and centrifugation yielded a fraction (pellet) that consisted mainly of tight junctions (zonulae occludentes). An hexagonal array of subunits similar to that previously found in a number of the unfractionated plasma membranes was demonstrated in all the membrane sheets of these preparations by negative staining. It is concluded that the hexagonal subunit pattern is present in the tight junctions, and that this structural differentiation may be related to the intercellular diffusion afforded by the junctional membrane.

The study on a new type of low-profile and passive radar retro-reflector

2014 ◽  
Author(s):  
Li Li ◽  
Fengwei Yao ◽  
Qiping Chen ◽  
Xiaobing Wang ◽  
Kun Cai ◽  
...  
Keyword(s):  
Passive Radar ◽  
Low Profile ◽  
New Type

Studies On Plasma Membranes

1967 ◽  
Vol 2 (4) ◽  
pp. 499-512
Author(s):  
E. L. BENEDETTI ◽  
P. EMMELOT
Keyword(s):  
Sialic Acid ◽  
Tight Junctions ◽  
Plasma Membranes ◽  
Iron Hydroxide ◽  
Chelating Agent ◽  
Colloidal Iron ◽  
Outer Leaflet ◽  
Liver Membranes ◽  
Junctional Complexes ◽  
Pre Treatment

Plasma membranes were isolated from rat liver and a transplanted rat hepatoma of the hepatocellular type. After glutaraldehyde fixation the membranes were treated with colloidal iron hydroxide (CIH) at pH 1.7, which was found to react specifically with the neuraminidase-sensitive sialic acid of the liver membranes. The CIH-reactive, neuraminidase-sensitive sialic acid, comprising 70% of the membrane-bound sialic acid, was exclusively located in the outer leaflet of the liver membranes as shown by the rather regular distribution of electron-dense CIH granules. This granular, asymmetric type of staining was also observed in the hepatoma membranes, which contained some 50% more sialic acid than did the liver membranes. In addition, the hepatoma membranes showed an intense and uniform staining by CIH of short segments of both membrane leaflets; the latter type of staining was but little impaired by neuraminidase pre-treatment. None of the junctional complexes of the liver membranes was stained by CIH. Tight junctions were very rarely observed in the hepatoma membrane preparations, and the desmosomes and intermediate junctions of these membranes not infrequently exhibited a loosened appearance exposing CIH-reactive neuraminidase-sensitive sialic acid at their opposite plates. This aspect could be induced in the desmosomes and intermediate junctions, but not in the tight junctions, by pre-treatment of the liver membranes with the chelating agent ethylenediaminetetra-acetate.

Effect of tumour angiogenesis factors on the membrane of capillary and aortic endothelial cells: an e.s.r. spin-label study

1984 ◽  
Vol 68 (1) ◽  
pp. 153-162
Author(s):  
N.J. Dodd ◽  
S. Kumar
Keyword(s):  
Endothelial Cells ◽  
Spin Label ◽  
Plasma Membranes ◽  
Detectable Effect ◽  
Aortic Endothelial Cells ◽  
Whole Cells ◽  
Membrane Order ◽  
Migration Factor ◽  
Aortic Endothelial

Two distinct factors have been separated from an angiogenic extract of a rat Walker 256 carcinoma, one inducing proliferation and the other migration of capillary endothelial cells in vitro, but having no detectable effect on aortic endothelial cells. The influence of these factors on the order of plasma membranes of these cells was examined by electron spin resonance, using the lipophilic spin label 5-doxyl stearic acid. No detectable effect was observed on treating whole cells or isolated membranes with proliferation factor. In contrast, exposure of capillary endothelial cell membranes to migration factor caused a reduction of membrane order, particularly at temperatures above 30 degrees C. The migration factor had no detectable effect on membrane order of aortic endothelial cells.

Tight junctions

1998 ◽  
Vol 111 (5) ◽  
pp. 541-547 ◽  
Author(s):  
M.S. Balda ◽  
K. Matter
Keyword(s):  
Endothelial Cells ◽  
Cell Growth ◽  
Tight Junctions ◽  
Diffusion Barrier ◽  
Basolateral Membrane ◽  
Intercellular Junctions ◽  
Cellular Level ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Membrane Components

Tight junctions are the most apical intercellular junctions of epithelial and endothelial cells and create a regulatable semipermeable diffusion barrier between individual cells. On a cellular level, they form an intramembrane diffusion fence that restricts the intermixing of apical and basolateral membrane components. In addition to these well defined functions, more recent evidence suggests that tight junctions are also involved in basic cellular processes like the regulation of cell growth and differentiation.

Oxidative Stress Induces a Breakdown of the Cytoskeleton and Tight Junctions of the Corneal Endothelial Cells

2021 ◽  
Author(s):  
Anupama Chalimeswamy ◽  
Marasarakottige Yogananda Thanuja ◽  
Sudhir H. Ranganath ◽  
Kaveet Pandya ◽  
Uday B. Kompella ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Tight Junctions ◽  
Corneal Endothelial Cells

scholarly journals STUDY OF THE EFFECT OF HYPOTHERMIC CONSERVATION ON THE INTRACELLULAR SODIUM CONCENTRATION IN THE ENDOTHELIUM OF CORNEAL TRANSPLANTS

2018 ◽  
Vol 22 (4) ◽  
pp. 433-437
Author(s):  
G. S. Baturina ◽  
I. G. Palchikova ◽  
A. A. Konev ◽  
E. S. Smirnov ◽  
L. E. Katkova ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membranes ◽  
Sodium Concentration ◽  
Intracellular Sodium ◽  
Sodium Balance ◽  
Human Cornea ◽  
Sodium Permeability ◽  
Custom Made ◽  
Intracellular Sodium Concentration ◽  
Cornea Endothelium

Endothelial keratoplasty has become the treatment of choice for corneal endothelial dysfunction. Advancements in the surgical treatment of corneal endothelial diseases depend on progress in graft conservation and its related advantages in assessing the suitability of grafts for transplantation. Transport of water and ions by cornea endothelium is important for the optic properties of cornea. In this work, we study the intracellular sodium concentration in cornea endothelial cells in samples of pig cornea that underwent hypothermic conservation for 1 and 10 days and endothelial cells of human cornea grafts after 10-day conservation. The concentration of intracellular sodium in preparations of endothelial cells was assayed using fluorescent dye SodiumGreen. The fluorescent images were analyzed with the custom-made computer program CytoDynamics. An increased level of intracellular sodium was shown in the endothelium after 10-day conservation in comparison with one-day conservation (pig samples). Sodium permeability of pig endothelial cell plasma membranes significantly decreased in these samples. Assessment of intracellular sodium in human cornea endothelium showed a higher level – as was in analogues pig samples of the corneal endothelium. The assay of the intracellular sodium balance concentration established in endothelial cells after hypothermic conservation in mediums L-15 and Optisol-GS showed a significant advantage of specialized me dium Optisol-GS. The balanced intracellular concentration after 10 days of hypothermic conservation was significantly lower in cells incubated at 4 °C in Optisol-GS (L-15, 128 ± 14,  n = 15; Optisol-GS, 108 ± 14, n = 11; mM, p < 0.001). Intracellular sodium concentration could be a useful parameter for assessing cornea endothelium cell viability.

scholarly journals Direct Current Stimulation Disrupts Endothelial Glycocalyx and Tight Junctions of the Blood-Brain Barrier in vitro

2021 ◽  
Vol 9 ◽  
Author(s):  
Yifan Xia ◽  
Yunfei Li ◽  
Wasem Khalid ◽  
Marom Bikson ◽  
Bingmei M. Fu
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Direct Current ◽  
Endothelial Glycocalyx ◽  
Microvascular Endothelial Cells ◽  
Bbb Permeability

Transcranial direct current stimulation (tDCS) is a non-invasive physical therapy to treat many psychiatric disorders and to enhance memory and cognition in healthy individuals. Our recent studies showed that tDCS with the proper dosage and duration can transiently enhance the permeability (P) of the blood-brain barrier (BBB) in rat brain to various sized solutes. Based on the in vivo permeability data, a transport model for the paracellular pathway of the BBB also predicted that tDCS can transiently disrupt the endothelial glycocalyx (EG) and the tight junction between endothelial cells. To confirm these predictions and to investigate the structural mechanisms by which tDCS modulates P of the BBB, we directly quantified the EG and tight junctions of in vitro BBB models after DCS treatment. Human cerebral microvascular endothelial cells (hCMECs) and mouse brain microvascular endothelial cells (bEnd3) were cultured on the Transwell filter with 3 μm pores to generate in vitro BBBs. After confluence, 0.1–1 mA/cm2 DCS was applied for 5 and 10 min. TEER and P to dextran-70k of the in vitro BBB were measured, HS (heparan sulfate) and hyaluronic acid (HA) of EG was immuno-stained and quantified, as well as the tight junction ZO-1. We found disrupted EG and ZO-1 when P to dextran-70k was increased and TEER was decreased by the DCS. To further investigate the cellular signaling mechanism of DCS on the BBB permeability, we pretreated the in vitro BBB with a nitric oxide synthase (NOS) inhibitor, L-NMMA. L-NMMA diminished the effect of DCS on the BBB permeability by protecting the EG and reinforcing tight junctions. These in vitro results conform to the in vivo observations and confirm the model prediction that DCS can disrupt the EG and tight junction of the BBB. Nevertheless, the in vivo effects of DCS are transient which backup its safety in the clinical application. In conclusion, our current study directly elucidates the structural and signaling mechanisms by which DCS modulates the BBB permeability.

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