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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute hypotension was produced in rats by using two experimental techniques: intravenous infusion of a ganglion-blocking agent (Arfonad), and venesection of a femoral vein. Horseradish peroxidase (HRP) was injected intravenously after each procedure, and subsequently observed in the inner ear by light and electron microscopy. In both experimental models, a large amount of tracer spread into the intercellular spaces, but it was halted by tight junctions bordering the stria vascularis. The endothelium exhibited a high distribution density of labelled vesicles, which suggested increased vesicular transport. There was no extravasation of HRP from capillaries in the spiral ligament in spite of the presence of some labelled pinocytotic vesicles. The present study was concerned with the discovery of enhanced capillary permeability of the stria vascularis under acute hypotension, as in the case of acute hypertension (Sakagami et al., 1984).
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PMID:Increased capillary permeability of the stria vascularis to HRP, induced by experimental acute hypotension in rats. 646 26

Evidence for the brain renin-angiotensin system being involved in the hypertension of the spontaneously hypertensive rat (SHR) includes central administration of angiotensin II (AII) antagonists and converting enzyme inhibitors that lower blood pressure in SHR. Using the unlabeled antibody enzyme method, we have found a significant difference in the distribution of brain angiotensin in SHR and Wistar-Kyoto controls (WKY). Six rats of each group were perfused with buffered picric acid-paraformaldehyde, and their brains sectioned at 50 and 100 mu. The sections were reacted with a 1:1000 dilution of AII antiserum for 36 hours followed by goat antirabbit immunoglobulin G and rabbit peroxidase antiperoxidase. For controls, preabsorption with AII, arginine vasopressin or preimmune serum were evaluated. The results showed over twice as many cells and fibers staining for AII-like immunoreactivity in SHR. The AII immunoreactive cell bodies were localized, in the order of their relative preponderance, in supraoptic and paraventricular nuclei of the hypothalamus, hippocampus, and cortex. The most prominent demonstration of AII-like immunoreactivity was observed in fiber profiles containing densely stained varicosities, which were present in many neuroanatomical subdivisions of the brain and brain stem including anterior and middle hypothalamus, basal ganglia, thalamus, locus coeruleus, nucleus of the solitary tract, limbic structures, and reticular formation. The increased fiber staining in the SHR was particularly evident in the frontal hypothalamic region, medial preoptic, and stria terminalis. We conclude that the results support the hypothesis of brain AII involvement in hypertension.
Hypertension
PMID:Angiotensin-like immunoreactivity in the brain of the spontaneously hypertensive rat. 675 94

Three models of hypertension were induced in Wistar rats: (1) aortic ligature between renal arteries, (2) uninephrectomy and Na-rich diet, (3) uninephrectomy, 0.9 per cent NaCl as drinking fluid and subcutaneous administration of desoxicorticosterone acetate (DOCA). We studied the aortic endothelium during the early (7 to 10 days) and late (40 days) phases of these models and quantified: (1) thymidine index and cell density using autoradiography on en face preparations, and (2) internal aortic circumference by planimetry. We also examined by means of scanning electron microscopy the surface morphology of the aorta in rats with aortic ligature. Thymidine index was constantly increased in the early phases of all models; it reverted to normal levels in the late phases. Endothelial cell density was slightly but significantly increased in the early and late phases after aortic ligature and in the early phase after Na-rich diet; it increased strikingly in the early and late phases after DOCA. There were no significant correlations between the variations of the internal aortic circumference and blood pressure, thymidine index, or cell density. Scanning electron microscopy showed no discontinuity of the endothelial cell layer either in the early or late phases after aortic ligature; bulging of endothelial cells into the lumen and appearance of cell clusters with numerous surface projections were seen during the early phase after aortic ligature. These changes produce a remodeling of the aortic endothelial layer which is maximal in the early phase after aortic ligature and in the early and late phases after DOCA and correlates with the previously reported increase of endothelial permeability to horseradish peroxidase in the same hypertensive situations.
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PMID:Remodeling of the rat aortic endothelial layer during experimental hypertension. Changes in replication rate, cell density, and surface morphology. 682 89

The distribution of renin in two cases of segmental renal hypoplasia was investigated by immunofluorescence and the peroxidase anti-peroxidase (PAP) method using an anti-human renin antiserum. Renin-containing cells were found only in hypoplasic segments in the vicinity of altered glomeruli and small arteries. Well-preserved renal cortex and areas of chronic atrophic pyelonephritis failed to show any demonstrable site of renin production. Whatever is the mechanism of the disease, the characterization of large numbers of renin-containing cells in the affected kidney support a role for the renin-angiotensin system stimulation in this form of hypertension.
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PMID:Renin localization in segmental renal hypoplasia. Immunohistochemical demonstration in two cases. 701 53

The effect of induced hypertension on the blood-brain barrier (BBB) change in Mongolian gerbils exposed to various periods of ischemia was studied. Evans blue dye was used to determine the BBB change in animals subjected to different levels of hypertension after 3 h ischemia. Horseradish peroxidase (HRP) was used in electronmicroscopic studies of animals subjected to 30 min, 1, 3 or 6 h ischemia and subsequently exposed for 30 min to varying periods and sequences of normo- and hypertension. Furthermore, HRP-labeled vesicle counts were performed in animals from the 30-min ischemia group. Our findings revealed that hypertension, after blood flow restoration following ischemia, induces and/or accelerates BBB damage by enhancing endothelial vesicular and/or tubulo-channel transport.
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PMID:Effect of hypertension on blood-brain barrier. Change after restoration of blood flow in post-ischemic gerbil brains. An electronmicroscopic study. 721 66

A new approach is described to study the mechanism of protein leakage through the endothelial cells in acute hypertension and after intracarotid infusion of hyperosmolar solutions. The luminarl surface of the cerebrovascular endothelial cells was labeled with choleragenoid-peroxidase before the blood-brain barrier (BBB) dysfunction was induced. Numerous pinocytotic vesicles and some transendothelial channels were formed and showed labeling of parts of their membranes. Our results indicate that the mechanism behind the protein leakage induced by hypertension and by hyperosmolar solutions is the same--ie, transendothelial pinocytosis.
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PMID:Induction of pinocytosis in cerebral vessels by acute hypertension and by hyperosmolar solutions. 740 Nov 97

The distribution of endogenous albumin and immunoglobulin G (IgG) has been studied by the immunoperoxidase technique in the superficial glomeruli of both normotensive and hypertensive (acute angiotensin II-induced) Munich-Wistar rats. Endogenous IgG has also been detected in rats immunized with horseradish peroxidase. Labeled antibodies have been applied to sections on a conventional manner as well as by an electrophoretic technique. The immunization of animals with horseradish peroxidase, as well as application of the electrophoretic technique, both result in a greater yield of labeled glomeruli. Albumin is present within the capillary lumina of control animals, penetrates the capillary walls, and extends into the urinary space. Endogenous IgG is mainly confined to lumina of glomerular capillaries, with only small amounts visible in the laminae rarae of the basement membrane. After acute hypertension induced by angiotensin II, there is increased staining of albumin and IgG in the basement membrane and of albumin in the urinary space. There is also penetration of IgG into Bowman's space. Both macromolecules are found in dilated mesangial channels. These modifications of glomerular permselectivity in hypertension are not accompanied by discernible ultrastructural changes in the peripheral capillary wall. It is suggested that the transcapillary passage of albumin and IgG is dependent upon hemodynamic factors and/or subtle changes in the filtering membrane.
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PMID:Glomerular permeability to endogenous proteins in the rat: effects of acute hypertension. 746 38

Comparative ultrastructural study of the sympathetic preganglionic neurons that innervated the superior cervical ganglion (SPN-scg) was made between spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats. After injection of choleragen subunit-B horseradish peroxidase (CB-HRP) into the superior cervical ganglion, three types of the sympathetic preganglionic neurons were identified according to their ultrastructural features. In both SHR and WKY rats, the neurons in the autonomic region of T1-T3 segments of the spinal cord showed a characteristic distribution pattern in which the Type I neurons were located more laterally in n. intermediolateralis pars funicularistic (ILf), and n. intermediolateralis pars principalis (ILp), Type III neurons more medially in n. intercalatus spinalis (IC), n. intercalatus pars paraependymalis (ICpe) and Type II neurons in n. intermediolateralis pars principalis (Ilp) as well as in n. intercalatus spinalis (IC). Of the three types of neurons, there was not noticeable ultrastructural difference in Type II and Type III neurons between the SHR and WKY rats. Some differences, however, were observed in Type I neurons between the two animals stains. In SHR, the nucleus of Type I neurons displayed many deep indentations and a greater number of profiles of Golgi apparatus. Three types of the axon terminal were found to make synaptic contacts with the labelled Type I neurons. Some proportional changes of the different axon terminals were observed between those of SHR and WKY rats. The results of this study suggest that the suppressive effect on the activity of the sympathetic preganglionic neurons in SHR may be attenuated which would result in an unbalanced activities of some of neurotransmitters on the sympathetic preganglionic neurons thereby leading to the onset of hypertension. The increase in the number of nuclear indentations and an increased activity in the Golgi complex may reflect an increase in the synthesis of some of the neurotransmitters or neuromodulators in the sympathetic preganglionic neurons or their axon terminals. The characteristic distribution patterns of the three types of neurons suggest that, of the three types of SPN-scg, only the Type I neurons may be implicated in the regulation of the cardiovascular system.
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PMID:An ultrastructural study of the sympathetic preganglionic neurons that innervate the superior cervical ganglion in spontaneously hypertensive rats and Wistar-Kyoto rats. 756 Sep 13

A 35-years old female with Jordans' anomaly was reported. She had been treated for diabetes mellitus and hypertension at another hospital. She was admitted to our hospital for operation for diabetic retinopathy on July 9, 1992. Wright-Giemsa stained peripheral blood smear revealed multiple vacuoles in the cytoplasm of the granulocytes and monocytes. Histochemical studies of these vacuoles showed positive for Sudan III but negative for peroxidase, alkaline phosphatase and PAS staining. Electron microscopic examination revealed that lipid containing vacuoles had no clear membrane and were not associated with cell organelles. Laboratory findings of the serum showed hyperglycemia (FBS 188mg/dl), high HbA1c level (9.4%) and mild type IIa hyperlipidemia. Abdominal sonogram and abdominal CT showed no remarkable abnormalities except for mild fatty liver. Her elder sister and daughter had similar morphological findings in granulocytes, monocytes and lymphocytes.
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PMID:[A case of Jordans' anomaly]. 786 17

A state of the anti-oxidation system in blood and the rate of lipid peroxidation were studied in patients with hypertension. High sensitivity of the anti-oxidation system enzymes to alterations in the diet fat composition was detected in the patients, nutrition of whom was evaluated in detail. Excessive doses of alpha-tocopherol, added to the diet enriched with omega 3-polyunsaturated fatty acids normalized lipid peroxidation and stabilized the enzyme activity involved in the anti-oxidation system. The integral parameter, proposed for evaluation of the anti-oxidation protection state and designated as "anti-oxidation index" involved estimation of catalase, superoxide dismutase, glutathione reductase and peroxidase activities as well as of content of malonic dialdehyde and diene conjugates in erythrocytes.
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PMID:[The antioxidant defense system in hypertension patients on a diet enriched with omega 3 polyunsaturated fatty acids and alpha-tocopherol]. 807 43


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