scholarly journals Ultrastructural changes of endothelium associated with thrombocytopenia

Blood ◽  
1975 ◽  
Vol 46 (4) ◽  
pp. 567-578 ◽  
Author(s):  
CS Kitchens ◽  
L Weiss
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Guinea Pig ◽  
Adult Male ◽  
Ultrastructural Changes ◽  
Endothelial Surface ◽  
Endothelial Junctions ◽  
The Relationship

Abstract In a study of the relationship between thrombocytopenia and increased vascular fragility, changes in the endothelium of capillaries and postcapillary venules of the tongue were examined by electron microscopy. Adult male albino rabbits (4 kg) were maintained thrombocytopenic (platelets less than 20,000/cu mm) up to 24 hr by one to three injections of guinea pig antirabbit platelet serum. Within 6 hr the normal projections and folds of the lumenal surface of the endothelial surface were largely effaced. In addition, the endothelium became thinner. In places, pores and membranous diaphragms were observed. Endothelial junctions appeared normal. Identical findings were observed if rabbits were made thrombocytopenic by administration of intraperitoneal busulfan. Intravenously administered Thorotrast was observed in endothelial cells and in the extravascular spaces within 3 min after injection into thrombocytopenic animals, while it was seen only intravascularly in control rabbits. With the spontaneous restoration of circulating platelets, the endothelium reverted to normal.

scholarly journals Ultrastructural changes of endothelium associated with thrombocytopenia

Blood ◽  
1975 ◽  
Vol 46 (4) ◽  
pp. 567-578 ◽  
Author(s):  
CS Kitchens ◽  
L Weiss
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Guinea Pig ◽  
Adult Male ◽  
Ultrastructural Changes ◽  
Endothelial Surface ◽  
Endothelial Junctions ◽  
The Relationship

In a study of the relationship between thrombocytopenia and increased vascular fragility, changes in the endothelium of capillaries and postcapillary venules of the tongue were examined by electron microscopy. Adult male albino rabbits (4 kg) were maintained thrombocytopenic (platelets less than 20,000/cu mm) up to 24 hr by one to three injections of guinea pig antirabbit platelet serum. Within 6 hr the normal projections and folds of the lumenal surface of the endothelial surface were largely effaced. In addition, the endothelium became thinner. In places, pores and membranous diaphragms were observed. Endothelial junctions appeared normal. Identical findings were observed if rabbits were made thrombocytopenic by administration of intraperitoneal busulfan. Intravenously administered Thorotrast was observed in endothelial cells and in the extravascular spaces within 3 min after injection into thrombocytopenic animals, while it was seen only intravascularly in control rabbits. With the spontaneous restoration of circulating platelets, the endothelium reverted to normal.

Permeability of neutral vs. anionic dextrans in cultured brain microvascular endothelium

1990 ◽  
Vol 259 (1) ◽  
pp. H162-H166 ◽  
Author(s):  
G. Sahagun ◽  
S. A. Moore ◽  
M. N. Hart
Keyword(s):  
Endothelial Cells ◽  
Endothelial Permeability ◽  
Cell Permeability ◽  
Microvascular Endothelium ◽  
Endothelial Surface ◽  
Luminal Side ◽  
Brain Microvessel ◽  
Relationship Of ◽  
The Relationship

The luminal surface of vascular endothelium contains glycocalyx residues that establish an overall negative charge. Recent evidence has suggested that local endothelial surface charge properties may account for the permeability properties of various macromolecules. It has also been suggested that altered membrane charge on the luminal side may play a role in thrombogenesis and atherogenesis. The relationship of macromolecule charge to endothelial cell permeability was examined in vitro using mouse brain microvessel endothelial cells grown to confluence on a nitrocellulose filter separating a double-chamber system. Endothelial permeability to 4K and 10K fluorescein-labeled neutral dextrans was compared with the permeability to 4K and 10K fluorescein-labeled anionic dextrans (sulfated). After 1 h, there was significantly greater permeability of neutral fluorescein-labeled dextran than of anionic fluorescein-labeled dextran in each particle size. In addition, there was significantly greater permeability of 4K than 10K fluorescein-labeled dextrans of either charge. The findings indicate that charge in addition to size plays an important role in the movement of macromolecules across cultured microvascular endothelial cells.

scholarly journals Prostacyclin production in vitro by rabbit aortic endothelium: correction for unstirred diffusional layers

Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1047-1052 ◽  
Author(s):  
EF Grabowski ◽  
GJ Naus ◽  
BB Weksler
Keyword(s):  
Endothelial Cells ◽  
Thrombin Generation ◽  
Ultrastructural Changes ◽  
Variable Degree ◽  
Transmission Electron ◽  
Endothelial Surface ◽  
Fluid Layers ◽  
Major Variable ◽  
Smooth Muscle Relaxant

Abstract The degree of mixing in fluid layers immediately adjacent to the endothelial surface is a major variable in assessment of prostacyclin (PGI2) production by cultured endothelial cells or intact vessel endothelium in vitro. Lack of adequate mixing should lead to underestimation of true production because PGI2 immediately adjacent to endothelium would be only poorly sampled upon buffer collection. Thoracic aortas from 38 New Zealand white rabbits were therefore excised, opened longitudinally, and mounted endothelial side uppermost in a buffer-filled chamber which excluded cut tissue edges from study. Production of PGI2 under unstirred and magnetically stirred conditions was measured by radioimmunoassay (RIA) for 6-keto-PGF1 alpha. For animals pretreated with the combination of papaverine and heparin (see below), unstimulated and arachidonate-stimulated 6-keto-PGF1 alpha increased with stirring rate toward limits of 2.9 and 28.5 ng/cm2/min, respectively. Unstimulated and stimulated 6-keto PGF1 alpha measured at 650 rpm, for example, were greater than their values at 0 rpm by factors of 3.5 (2P less than .01) and 3.7 (2P less than .001), respectively. The process of vessel excision, however, produces another variable: degree of injury to endothelium caused by such factors as secondary vessel contraction and thrombin generation. Vessel contraction and thrombin generation can be minimized, respectively, by the use of a smooth muscle relaxant and heparin administered prior to killing of the animals. The rabbits were, therefore, grouped according to intravenous (IV) treatment, prior to killing, with saline, papaverine (4 mg/kg), heparin (200 U/kg) or the combination of papaverine and heparin (same doses). As compared with pretreatment with saline, papaverine alone, or heparin alone, pretreatment with the combination of papaverine and saline led to increases in stimulated 6- keto-PGF1 alpha of 1.6- to 2.8-fold. By transmission electron microscopy, endothelium from animals pretreated with saline showed ultrastructural changes, including disruption of cytoplasm, separation without detachment of most endothelial cells from subendothelium, and focal areas of denudation. In contrast, ultrastructural integrity of endothelium was preserved in aortas of animals pretreated with combined papaverine and heparin. These results support the hypothesis that unstirred diffusional layers lead, in vitro, to underestimation of PGI2 production, especially when vessels are protected from excisional injury.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of castration on androgen receptors and gonadotropins in the pituitary of adult male viscachas

2014 ◽  
Vol 26 (7) ◽  
pp. 991 ◽  
Author(s):  
Verónica Filippa ◽  
Daiana Godoy ◽  
Edith Perez ◽  
Fabian Mohamed
Keyword(s):  
Electron Microscopy ◽  
Adult Male ◽  
Androgen Receptors ◽  
Light And Electron Microscopy ◽  
Regulatory Mechanisms ◽  
Ultrastructural Changes ◽  
Morphological Evidence ◽  
Pituitary Cells ◽  
Pars Distalis ◽  
Ventral Region

The aims of the present study were to determine whether castration results in quantitative immunohistochemical changes in androgen receptors (AR), LH-immunoreactive (IR) cells and FSH-IR cells, and to analyse the colocalisation of AR and gonadotropins in the pituitary pars distalis (PD) of viscachas. Pituitaries were processed for light and electron microscopy. AR-IR, LH-IR and FSH-IR cells were detected by immunohistochemistry. In morphometric studies, the percentage of AR-IR, LH-IR, FSH-IR, LH-IR/AR-IR and FSH-IR/AR-IR cells was determined. In intact viscachas, AR were distributed throughout the PD; they were numerous at the caudal end, with intense immunostaining. LH-IR cells and FSH-IR cells were found mainly in the ventral region and at the rostral end of the PD. Approximately 45%–66% of LH-IR cells and 49%–57% of FSH-IR cells expressed AR in the different zones of the PD. In castrated viscachas, there was a significant decrease in the percentage of AR-IR, LH-IR, FSH-IR, and FSH-IR/AR-IR cells. Some pituitary cells from castrated viscachas also exhibited ultrastructural changes. These results provide morphological evidence that gonadal androgens are directly related to the immunolabelling of AR, LH and FSH. Moreover, the colocalisation of AR and FSH is most affected by castration, suggesting the existence of a subpopulation of gonadotrophs with different regulatory mechanisms for hormonal synthesis, storage and secretion.

scholarly journals CLIC5A, a component of the ezrin-podocalyxin complex in glomeruli, is a determinant of podocyte integrity

2010 ◽  
Vol 298 (6) ◽  
pp. F1492-F1503 ◽  
Author(s):  
Binytha Wegner ◽  
Abass Al-Momany ◽  
Stephen C. Kulak ◽  
Kathy Kozlowski ◽  
Marya Obeidat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Ultrastructural Changes ◽  
Immunogold Electron Microscopy ◽  
Apical Plasma Membrane ◽  
Wild Type ◽  
Glomerular Injury ◽  
Filamentous Actin ◽  
Western Blots ◽  
Glomerular Endothelial Cells

The chloride intracellular channel 5A (CLIC5A) protein, one of two isoforms produced by the CLIC5 gene, was isolated originally as part of a cytoskeletal protein complex containing ezrin from placental microvilli. Whether CLIC5A functions as a bona fide ion channel is controversial. We reported previously that a CLIC5 transcript is enriched ∼800-fold in human renal glomeruli relative to most other tissues. Therefore, this study sought to explore CLIC5 expression and function in glomeruli. RT-PCR and Western blots show that CLIC5A is the predominant CLIC5 isoform expressed in glomeruli. Confocal immunofluorescence and immunogold electron microscopy reveal high levels of CLIC5A protein in glomerular endothelial cells and podocytes. In podocytes, CLIC5A localizes to the apical plasma membrane of foot processes, similar to the known distribution of podocalyxin and ezrin. Ezrin and podocalyxin colocalize with CLIC5A in glomeruli, and podocalyxin coimmunoprecipitates with CLIC5A from glomerular lysates. In glomeruli of jitterbug ( jbg/jbg) mice, which lack the CLIC5A protein, ezrin and phospho-ERM levels in podocytes are markedly lower than in wild-type mice. Transmission electron microscopy reveals patchy broadening and effacement of podocyte foot processes as well as vacuolization of glomerular endothelial cells. These ultrastructural changes are associated with microalbuminuria at baseline and increased susceptibility to adriamycin-induced glomerular injury compared with wild-type mice. Together, the data suggest that CLIC5A is required for the development and/or maintenance of the proper glomerular endothelial cell and podocyte architecture. We postulate that the interaction between podocalyxin and subjacent filamentous actin, which requires ezrin, is compromised in podocytes of CLIC5A-deficient mice, leading to dysfunction under unfavorable genetic or environmental conditions.

scholarly journals Effect of Electrocautery on Endothelial Integrity of the Internal Thoracic Artery: Ultrastructural Analysis with Transmission Electron Microscopy

2014 ◽  
Vol 41 (5) ◽  
pp. 484-490 ◽  
Author(s):  
Burak Onan ◽  
Mehmet Yeniterzi ◽  
Ismihan Selen Onan ◽  
Burak Ersoy ◽  
Suheyla Gonca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endothelial Cells ◽  
Internal Thoracic Artery ◽  
Ultrastructural Changes ◽  
Control Group ◽  
Elastic Tissue ◽  
Cytoplasmic Organelles ◽  
Transmission Electron ◽  
Sharp Dissection

The internal thoracic artery (ITA) is typically harvested from the chest wall by means of conventional electrocautery. We investigated the effects of electrocautery on endothelial-cell and vessel-wall morphology at the ultrastructural level during ITA harvesting. Internal thoracic artery specimens from 20 patients who underwent elective coronary artery bypass grafting were investigated in 2 groups. The ITA grafts were sharply dissected with use of a scalpel and clips in the control group (n=10) and were harvested by means of electrocautery in the study group (n=10). Each sample was evaluated for intimal, elastic-tissue, muscular-layer, and adventitial changes. Free flow was measured intraoperatively. Light microscopic examinations were performed after hematoxylin-eosin and Masson's trichrome staining. Transmission electron microscopy was used to evaluate ultrastructural changes in the endothelial cells and vessel walls of each ITA. In the sharp-dissection group, the endothelial surfaces were lined with normal amounts of original endothelium, endothelial cells were distinctly attached to the basal lamina, cytoplasmic organelles were evident, and intercellular junctional complexes were intact. Conversely, in the electrocautery group, the morphologic integrity of endothelial cells was distorted, with some cell separations and splits, contracted cells, numerous large cytoplasmic vacuoles, and no visible cytoplasmic organelles. The subendothelial layer exhibited disintegration. Free ITA flow was higher in the sharp-dissection group (P=0.04). The integrity of endothelial cells can be better preserved when the ITA is mobilized by means of sharp dissection, rather than solely by electrocautery; we recommend a combined approach.

scholarly journals Vascular Changes During Regression of the Corpus Luteum of the Guinea Pig

1981 ◽  
Vol 34 (6) ◽  
pp. 649 ◽  
Author(s):  
MI Hossain ◽  
JD O'Shea
Keyword(s):  
Endothelial Cells ◽  
Guinea Pig ◽  
Corpus Luteum ◽  
Light And Electron Microscopy ◽  
Substantial Reduction ◽  
Ultrastructural Changes ◽  
Cell Degeneration ◽  
Luteal Regression ◽  
Small Vessels ◽  
Capillary Bed

Quantitative and qualitative changes in the microvasculature of the corpus luteum of the guinea pig during cyclical luteal regression were studied by light and electron microscopy. During luteal regression, between day 12 of the oestrous cycle and day 1 of the next cycle, there was a reduction in the extent of the luteal capillary bed as measured both by 'hit' counts and by differential counts of all nucleated cells. Luteal cells made up a constant proportion of :::::: 60 % of the luteal tissue area up to day 1 of the next cycle, but had increased as a proportion of all nucleated cells by that stage. Both fibroblasts and macrophages increased in number and in area occupied during luteal regression. Ultrastructural changes in capillaries during luteal regression included, an increased incidence and degree of protrusion of endothelial cells into the lumina of small blood vessels, and degeneration and death of many endothelial cells. In spite of the widespread presence of endothelial cell degeneration, most small vessels retained a continuous lining of apparently viable endothelium. It is concluded that in this species there is a rapid and substantial reduction in the luteal capillary bed, which commences during the early stages of luteal regression, and a mechanism is proposed by which the capillary bed may be reduced while retaining its integrity.

scholarly journals Permeability of muscle capillaries to microperoxidase.

1978 ◽  
Vol 76 (2) ◽  
pp. 341-359 ◽  
Author(s):  
S L Wissig ◽  
M C Williams
Keyword(s):  
Electron Microscopy ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Intravenous Injection ◽  
Cylindrical Channel ◽  
Small Pore ◽  
Endothelial Junctions ◽  
Capillary Endothelial Cells ◽  
Single Vesicle ◽  
Muscle Capillaries

In this study we attempted to identify a morphologic counterpart of the small pore of muscle capillaries. The existence of such a pore has been postulated by physiologists to explain the permeability of muscle capillaries to small macromolecules. We injected mice intravenously with microperoxidase (MP) and fixed specimens of diaphragm at intervals of 0-250 s after the injection to localize the tracer by electron microscopy. The small size of MP (1,900 mol wt and 20 A molecular diameter [MD]) ensures its ready passage through the small pore since the latter is thought to be either a cylindrical channel 90 A in diameter or a slit 55 A wide. MP appears in the pericapillary interstitium within 30 s of initiation of its intravenous injection. The patterns of localization of MP observed within clefts between adjacent capillary endothelial cells indicate that some endothelial junctions are permeable to this tracer. Although small vesicles transfer MP across the endothelium, we do not believe that the vesicles transfer substantial amounts of MP into the pericapillary interstitium. We did not obtain evidence that MP crosses the endothelium of capillaries through channels formed either by a single vesicle or by a series of linked vesicles opening simultaneously at both surfaces of the endothelial cell. From our observations we conclude that some endothelial junctions of capillaries are permeable to MP, and that these permeable junctions are a plausible morphologic counterpart of the small pore.

scholarly journals Prostacyclin production in vitro by rabbit aortic endothelium: correction for unstirred diffusional layers

Blood ◽  
1985 ◽  
Vol 66 (5) ◽  
pp. 1047-1052
Author(s):  
EF Grabowski ◽  
GJ Naus ◽  
BB Weksler
Keyword(s):  
Endothelial Cells ◽  
Thrombin Generation ◽  
Ultrastructural Changes ◽  
Variable Degree ◽  
Transmission Electron ◽  
Endothelial Surface ◽  
Fluid Layers ◽  
Major Variable ◽  
Smooth Muscle Relaxant

The degree of mixing in fluid layers immediately adjacent to the endothelial surface is a major variable in assessment of prostacyclin (PGI2) production by cultured endothelial cells or intact vessel endothelium in vitro. Lack of adequate mixing should lead to underestimation of true production because PGI2 immediately adjacent to endothelium would be only poorly sampled upon buffer collection. Thoracic aortas from 38 New Zealand white rabbits were therefore excised, opened longitudinally, and mounted endothelial side uppermost in a buffer-filled chamber which excluded cut tissue edges from study. Production of PGI2 under unstirred and magnetically stirred conditions was measured by radioimmunoassay (RIA) for 6-keto-PGF1 alpha. For animals pretreated with the combination of papaverine and heparin (see below), unstimulated and arachidonate-stimulated 6-keto-PGF1 alpha increased with stirring rate toward limits of 2.9 and 28.5 ng/cm2/min, respectively. Unstimulated and stimulated 6-keto PGF1 alpha measured at 650 rpm, for example, were greater than their values at 0 rpm by factors of 3.5 (2P less than .01) and 3.7 (2P less than .001), respectively. The process of vessel excision, however, produces another variable: degree of injury to endothelium caused by such factors as secondary vessel contraction and thrombin generation. Vessel contraction and thrombin generation can be minimized, respectively, by the use of a smooth muscle relaxant and heparin administered prior to killing of the animals. The rabbits were, therefore, grouped according to intravenous (IV) treatment, prior to killing, with saline, papaverine (4 mg/kg), heparin (200 U/kg) or the combination of papaverine and heparin (same doses). As compared with pretreatment with saline, papaverine alone, or heparin alone, pretreatment with the combination of papaverine and saline led to increases in stimulated 6- keto-PGF1 alpha of 1.6- to 2.8-fold. By transmission electron microscopy, endothelium from animals pretreated with saline showed ultrastructural changes, including disruption of cytoplasm, separation without detachment of most endothelial cells from subendothelium, and focal areas of denudation. In contrast, ultrastructural integrity of endothelium was preserved in aortas of animals pretreated with combined papaverine and heparin. These results support the hypothesis that unstirred diffusional layers lead, in vitro, to underestimation of PGI2 production, especially when vessels are protected from excisional injury.(ABSTRACT TRUNCATED AT 400 WORDS)

Ultrastructural Changes of Canine Kidneys During 24-Hour Perfusion on a LI-400 Preservation System

1971 ◽  
Vol 29 ◽  
pp. 316-317
Author(s):  
M. O. Magnusson ◽  
D. G. Osborne ◽  
T. Shimoji ◽  
W. S. Kiser ◽  
W. A. Hawk
Keyword(s):  
Electron Microscopy ◽  
Electrolyte Solution ◽  
Ultrastructural Changes ◽  
Midline Incision ◽  
Short Term ◽  
Pentobarbital Anesthesia ◽  
Pulsatile Perfusion

Short term experimental and clinical preservation of kidneys is presently best accomplished by hypothermic continuous pulsatile perfusion with cryoprecipitated and millipore filtered plasma. This study was undertaken to observe ultrastructural changes occurring during 24-hour preservation using the above mentioned method.A kidney was removed through a midline incision from healthy mongrel dogs under pentobarbital anesthesia. The kidneys were flushed immediately after removal with chilled electrolyte solution and placed on a LI-400 preservation system and perfused at 8-10°C. Serial kidney biopsies were obtained at 0-½-1-2-4-8-16 and 24 hours of preservation. All biopsies were prepared for electron microscopy. At the end of the preservation period the kidneys were autografted.

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