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

The effect of cavinton on the systemic (by the method of diluting Evans blue according to Stewart-Hamilton) and cerebral (by the method of rheoencephalography) hemodynamics was examined in 38 patients with chronic insufficiency of the cerebral circulation (CICC) in the presence of either atherosclerosis alone (n = 22) and its combination with arterial hypertension (n = 16). Cavinton decreased the peripheral vascular resistance and the tone of the small and median vessels of the brain, increased the cardiac output and improved the rheological properties of the blood (it lowered the globular volume, viscosity and hematocrit). The best results were attained with the parenteral administration of the drug. Indications for and contraindications to cavinton in patients with CICC are discussed.
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PMID:[Effect of cavinton on systemic and cerebral hemodynamics of patients with chronic cerebral circulatory insufficiency]. 407 32

The cerebrovascular lesions of severe chronic hypertension were studied by light microscopy in perfusion-fixed, subserially sectioned brains from stroke-prone spontaneously hypertensive rats (SHRSP). The leakage and spread of plasma proteins were visualized by immunohistochemical detection of extravasated fibrinogen and by using an exogenous marker (Evans blue injected i.v.) for blood-brain barrier (BBB) dysfunction. In most SHRSP the hypertension did not lead to major BBB lesions in spite of a mean arterial pressure around 200 mm Hg at 6-9 months of age. Multifocal BBB damage occurred in a minor group of SHRSP, particularly within the cortex and the deep gray matter. A close spatial correlation was found between the leakage-spread of plasma constituents and the neuropathologic alterations. Fibrinoid degeneration of penetrating arterioles was found within the leakage sites. The surrounding gray matter showed petechial hemorrhages and abundant proteinaceous exudates rich in antifibrinogen-positive material. The current leakage of Evans blue and wide spread of fibrinoid substances suggested long-lasting damage to the BBB. Most neurons within the edematous gray matter had well preserved nuclei surrounded by a rim of cytoplasm with ill-defined outline as if vacuolation or lysis of the peripheral cytoplasm had occurred. The sponginess of the tissue progressed in severe cases to formation of necrotic cysts. Condensed acidophilic neurons were seen in the border zone between the edematous and more compact gray matter. The appearance and distribution of the gray matter lesions deviated in many respects from those commonly seen in regional ischemic infarcts. The fibrin thrombi found close to the cysts might be regarded as secondary events. The extensive spread of antifibrinogen-positive material within the white matter seemed to originate mainly from the chronic leakage sites in the gray matter. Increased number of large astrocytes were seen within the leakage sites and along the spreading pathways for the edema constituents. The white matter showed a rarefied texture with widely dispersed nerve fiber tracts, volume expansion, and occasional cyst formation. The results indicate a crucial pathophysiologic role for the egress, spread, and accumulation of vasogenic edema in the development of the cerebrovascular lesions in SHRSP.
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PMID:Cerebrovascular lesions in stroke-prone spontaneously hypertensive rats. 409 Sep 40

Rats were subjected to adrenaline-induced acute hypertension during either the day or night. Albumin leakage into the brain was studied with Evans blue and 125I labeled serum albumin. The leakage was significantly lower during the night than during the day (P less than 0.001). d,1-propranolol had a protective effect (P less than 0.001) during the day and a slight reduction of the radioactivity (P less than 0.05 in some parts of the brain) was obtained by metoprolol (10 mg/kg) but not by butoxamine (10 mg/kg). None of the drugs reduced the tracer leakage during the night. The results suggest that the degree of alertness is of importance for the function of the blood-brain barrier in acute hypertension. However, the present experimental situation does not allow a separation of the effect of alertness per se and dark/light cycles. The changed vulnerability during the night could be related to enhanced neuronal activity, altered beta-adrenoreceptor sensitivity or to hormonal factors.
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PMID:The blood-brain barrier in adrenaline-induced hypertension. Circadian variations and modification by beta-adrenoreceptor antagonists. 611 Nov 72

In 102 patients with chronic cerebral circulation insufficiency (due to atherosclerosis in 70 and atherosclerosis plus arterial hypertension in 32 patients) the general hemodynamic parameters were examined using the method of Evans blue (T-1824) dilution in comparison with rheoencephalographic findings. In all the patients disturbances of the general and cerebral hemodynamics were revealed, these disturbances being more marked in the patients with atherosclerosis complicated with arterial hypertension. Rheopolyglucin combined with antospasmodics and cardiac glycosides was found to produce a beneficial effect on the rheological properties of the blood and the parameters of the general and cerebral circulation.
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PMID:[Changes in the systemic hemodynamics of patients with chronic cerebrovascular insufficiency]. 615 10

The object of this investigation was to study the effects of prostacyclin (PGI2) upon the evolution of acute focal cerebral ischemia in the cat. Twenty-five fasted adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion. Eleven cats received an intracarotid infusion of PGI2 in buffered saline pH 10.5 (100 ng/kg/min at 0.01 ml/kg/min), and 11 cats received intracarotid buffered saline pH 10.5 (0.01 ml/kg/min) without therapeutic agents. Treatment with PGI2 was started upon MCA occlusion and continued for 6 hours. Thirty minutes prior to perfusion, the animals were given fluorescein and Evans blue by intravenous injection. The cats were perfused-fixed in vivo with carbon and buffered formalin 6 hours after MCA occlusion. Another 3 cats received tritium labeled intracarotid PGI2, and peripheral venous samples were collected and assayed for PGI2 plasma levels. Mean arterial pressure was stable in PGI2 treated animals during 6 hours of MCA occlusion, while untreated cats had significant progressive hypertension during that period. The rCBF (measured by the intracarotid 133Xe method) decreased markedly in all animals immediately upon MCA occlusion. However, untreated animals had a significant progressive improvement in rCBF during the occlusion period, while PGI2 treated animals had no such improvement. Quantitative EEG changes, gross edema, areas of fluorescein extravasation, patterns of carbon perfusion, and infarct size were not significantly different in the two groups. While most untreated animals had marked Evans blue extravasation after 6 hours of MCA occlusion, most PGI2 treated animals had no such extravasation, indicating some protection of the blood-brain barrier in these animals.
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PMID:Treatment of acute focal cerebral ischemia with prostacyclin. 634 Feb 54

A method is described for implanting arterial and venous cannulas in rats that requires only minor surgery. Catheters are introduced into the abdominal aorta through the ventral tail artery and into the vena cava through a lateral tail vein. The wounds are covered with an acrylic cuff and the catheters are brought out through a stainless steel spiral connected to the cuff and then attached to top of a metabolism cage used to house the rat. This method makes possible continuous access to the catheters in undisturbed, mobile animals. Using this model we compared mean arterial pressure, heart rate, plasma renin activity, and plasma catecholamine levels in freely moving Long-Evans rats and in Brattleboro homozygous rats.
Hypertension
PMID:Chronic arterial and venous catheterization of conscious, unrestrained rats. 639 88

The plasma renin activity (PRA), plasma volume (PV), urinary excretion of Kallikrein (UK) and PGE2, PGF2 alpha, 6-keto PGF1 alpha and TXB2 were measured in 24 ambulant patients without treatment on normal sodium diets with pregnancy-induced hypertension (HT) (diastolic BP greater than or equal to 90 mmHg, appearing after 20 weeks' pregnancy and absent 2 months after delivery). The UK was measured by an esterase technique, prostaglandins by radioimmunological assay and PV by dye dilution (Evans blue). Two subgroups of patients were identified according to the evolution of their blood pressure at rest at home; the first (7 patients) with labile HT, and the second (14 patients) with permanent HT. The PRA was significantly lower (p less than 0,001) in patients with permanent compared to labile hypertension (4,7 +/- 0,3 compared to 12,2 +/- 0,8 ng/ml/h) and compared to a control group of normotensive pregnant women (6,5 +/- 0,5). The PV, expressed as a percentage of the theoretical volume with respect to the stage of pregnancy and body surface area was low in both groups. In permanent HT: 1) there was no correlation between PV and PRA, 2) a positive correlation between UK and urinary 6-keto PGF1 alpha (r = 0,62; p less than 0,001) and PGE2 (r = -0,51, p less than 0,05). Discriminative linear analysis showed that urinary 6-keto PGF1 alpha was mainly related to PRA and to a lesser degree to UK.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Renin-angiotensin-aldosterone system, blood volume, serum uric acid and urinary excretion of prostaglandins and kallikrein in the arterial hypertension induced by pregnancy]. 644 41

The purpose of this randomized, prospective study was to investigate the effects of diuretics on plasma volume findings and perinatal outcome in pregnancies complicated by mild long-term hypertension. Twenty patients were in their first trimester and were receiving diuretics at time of entry to the study: Ten patients were allowed to continue their diuretic medication throughout pregnancy (diuretic group), whereas for the other 10 patients, diuretics were discontinued immediately. Plasma volume was serially measured throughout pregnancy with the use of the Evans blue dye-dilution technique. Initial plasma volume was similar in the two groups. However, in the diuretic group, subsequent plasma volume findings at various stages of gestation were markedly reduced when compared to respective plasma volume findings in the other group. In addition, plasma volume expansion was minimal in the diuretic group (mean increase of 18%), whereas it was normal in the other group (mean increase of 52%). Two patients in the diuretic group and one patient in the other group required other antihypertensive medication. There was no difference in perinatal outcome between the two groups. These results suggest that in hypertensive pregnancies, diuretics prevent normal plasma volume expansion without influencing perinatal outcome.
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PMID:Effects of diuretics on plasma volume in pregnancies with long-term hypertension. 650 9

With the Evans blue dye-dilution technique, plasma volume was serially measured at 29 to 33 weeks' and 34 to 40 weeks' gestation in 74 pregnant women with documented mild pregnancy-induced hypertension (PIH) and 25 well-matched normotensive primigravid women. The relationship of plasma volume to clinical course, perinatal outcome, and other laboratory findings was subsequently analyzed. The patients with mild PIH were categorized into two groups based on infant outcome: appropriate for gestational age (AGA) and small for gestational age (SGA). The mean age, height, and hematocrit of the study and control patients were similar. The group of patients with mild PIH had significantly higher mean arterial blood pressures and uric acid levels (p less than 0.001). There was no difference in mean plasma volume findings between the normotensive group and the mild PIH group delivered of AGA infants. Plasma volume was reduced only in pregnancies with mild PIH with delivery of SGA infants. It is concluded that plasma volume is not reduced in most patients with mild PIH. However, plasma volume might be useful in identifying a subgroup of patients with mild PIH at risk for delivering an SGA infant.
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PMID:Plasma volume findings in patients with mild pregnancy-induced hypertension. 661 81

Evidence was found for different outcomes to middle cerebral artery occlusion in the young genetically hypertensive stroke-prone rat (SHRSP) compared to sham operated controls and the Wistar Kyoto rat (WKY). Qualitatively and quantitatively different gross lesions marked by Evans blue-albumin, cortical atrophy, large areas of strikingly altered cortical histology, postoperative survival and motor behavioral deficits differentiate young SHRSP from sham operated controls and the normotensive WKY. We conclude that the limited focal lesion observed in normotensive and sham operated rats is primarily due to surgical trauma of exposing the vessel and passing the ligature deep to it. The grossly larger and qualitatively different lesion in the SHRSP is the result of an inadequate circulation provided by the dorsal cerebral arterial collaterals. Since the 5-6 week old SHRSP were only mildly hypertensive (systolic blood pressure 140 mm Hg), the inadequate collateral circulation appears to be related to either a genetic or acquired problem rather than being secondary to a vascular lesion of chronic hypertension.
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PMID:Differential outcome to middle cerebral artery occlusion in spontaneously hypertensive stroke-prone rats (SHRSP) and Wistar Kyoto (WKY) rats. 665 39


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