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Results 551 - 600 of 1260
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Eliades D - - 1989
Studies in Lichstein's laboratory suggest that the endogenous digitalislike substance implicated in low renin hypertension might be a steroidal dienolide derivative. If this is true, the bufadienolides should block potassium vasodilation and enhance norepinephrine vasoconstriction, constrict blood vessels, raise blood pressure, and produce natriuresis and diuresis. We have therefore examined ...
Laragh J H - - 1989
Modern antihypertensive therapy is enriched by an explosion in drug development that makes available increasingly specific agents whose effects have advanced our understanding of pressor mechanisms. This and other research into hypertensive mechanisms has defined the clinical, pharmacological, and endocrinologic heterogeneity of human hypertension. The sum of these developments is ...
Montier F - - 1989
In anesthetized dogs, a 15-min intravenous (i.v.) infusion of fenoldopam (2.0 micrograms/kg/min) produced a decrease in mean aortic blood pressure (MAP) and an increase in renal blood flow (RBF) and plasma renin activity (PRA). The hypotensive effect attained a maximum within 5 min and then waned by approximately 30% at ...
Malvin R L - - 1989
We previously demonstrated the presence of six active forms of renin in rats, based on their isoelectric points (pI). Intravenous or intraventricular injections yielded different renal effects with the different forms. Additional work is presented supporting the hypothesis that these forms are functionally different. Renin form 2 (pI = 5.7), ...
Blaine E H - - 1989
Mean arterial blood pressure (MAP) was 100 +/- 4 mmHg in a group (n = 3) of conscious sodium-deficient dogs. A 3-day infusion of the renin inhibitor isovaleryl -His-Pro-Phe-His-Sta-Leu-Phe-NH2 (SCRIP) lowered MAP to an average of 79 +/- 4 mmHg. Termination of the infusion resulted in a prompt rise in ...
Wood J M - - 1989
We have developed marmoset models for the in vivo evaluation of primate-specific inhibitors of human renin. After acute intravenous administration to normotensive sodium-depleted marmosets, renin inhibitors of different structural types induced a maximum hypotensive response of a magnitude similar to that induced after angiotensin converting enzyme (ACE) inhibition. The response ...
Sambhi M P - - 1989
Inhibitors of the renin-angiotensin system, which are promising therapeutic agents with few side effects, have measurably improved the management of many patients with primary or secondary hypertension and those with heart failure. This paper briefly reviews the emerging evidence for the potential risk associated with long-term inhibition of the renin ...
Campbell D J - - 1989
There is increasing evidence that a major site of production of angiotensin I and II is peripheral tissue. Both angiotensin I and II are present in venous blood in amounts far too high to be explained by their generation in blood alone, given the extensive conversion of angiotensin I to ...
Michel J B - - 1989
To block the renin-substrate reaction by immunological tools is a long-standing dream. Since 1951 active immunization and the passive transfer of antirenin antisera have been successfully carried out in different species and in different experimental models of hypertension and normotension. These studies indicated that renin is a powerful immunogenic protein, ...
Linz W - - 1989
Based on molecular, biological, biochemical, and pharmacological data, evidence is presented for a cardiac renin-angiotensin system. Using radiolabeled cRNA probes prepared from specific cDNA fragments, we were able to document renin and angiotensinogen gene expression in atria and ventricles of the rat heart by Northern blot and liquid hybridization analysis. ...
Pickering T G - - 1989
Evidence from animal studies demonstrates that the renin-angiotensin (ANG II) system and sodium retention play major roles in experimental renovascular hypertension (RVH). Two basic models have been described. In the first, one-clip two-kidney Goldblatt hypertension, the ischemic kidney secretes renin, which leads to increased ANG II formation and hence elevation ...
Okada Y - - 1989
Cyclic replacement therapy using estrogen and progesterone was instituted in 28 patients with gonadal dysgenesis and 13 patients with hypopituitarism. When estriol was given at a dose of 2 mg per day, 10 patients (9 gonadal dysgenesis and 1 hypopituitarism) developed hyperreninemia and 3 of the 10 patients (all gonadal ...
Cluzel P - - 1989
The effect on blood pressure of the dihydropyridine derivative nicardipine was studied in 87 essential hypertensive patients aged 25-77 years. A total cumulative dose of 8.75 mg nicardipine was administered over a 30-min period by continuous intravenous infusion. The dose was doubled every 10 min from 1.25 to 5.0 mg. ...
Scheuer D A - - 1989
We have reported that the renin response to systemic hypotension during a simultaneous increase in left atrial pressure (LAP) depends, in part, on intact renal nerves. Because efferent neural control of renin release is mediated by renal sympathetic nerves, we tested the hypothesis that withdrawal of renal sympathetic tone is ...
Ryan K L - - 1989
This study primarily sought to determine whether the role of vasopressin (VP) in maintenance of arterial blood pressure is enhanced in awake, chronically instrumented baboons after 68-72 h of dehydration. This question was approached by pharmacologically blocking vasopressin V1-receptors in euhydrated and dehydrated baboons with or without a normally functioning ...
Porter J P - - 1989
It was recently reported that electrical stimulation of the hypothalamus could enhance the renin response to reductions in renal perfusion pressure. However, electrical stimulation of brain sites may activate neural pathways that never function physiologically. In the present investigation an external stress in the form of a jet of air ...
de Mey C - - 1989
The administration of a single dose of atenolol 50 mg 1 h before a standard 3100 kJ cold meal in fasting healthy subjects reduced the supine preprandial heart rate and systolic blood pressure, and blunted the postural and postprandial rises in mean heart rate and systolic blood pressure relative to ...
Hartmann J - - 1989
A hypotensive effect of an orally-administered cyclopeptide somatostatin analog, MK-678, has been demonstrated in a hypertensive diabetic rat model. Sustained blood pressure reduction failed to occur when the drug was administered to the spontaneously hypertensive rat. The mechanism of hypotension appears independent of effects on a variety of hormones including ...
Corvol P - - 1989
Renin inhibitors represent an alternative to angiotensin-converting enzyme inhibitors (ACEI) for the treatment of hypertension. They inhibit the renin-angiotensin system at its first and rate limiting step, the renin-angiotensinogen reaction. Passive administration of angiotensinogen or renin antibodies lowers blood pressure in primates to the same extent as ACEI. Chronic active ...
Musumeci V - - 1989
Central dopaminergic activity (CDA) may be involved in blood pressure control as a negative modulator of sympathetic outflow. In this study the plasma PRL changes produced by mental stress (a colour-word conflict test, CWT) were investigated in normals (NT, n.15) and stable hypertensives (HT, n.16) and the PRL response, as ...
Singer D R - - 1989
Dietary sodium restriction alone is effective in lowering blood pressure in some, but not all, patients with essential hypertension. Homeostatic mechanisms, including activation of the renin-aldosterone system, may counteract the effects of sodium restriction. Angiotensin converting enzyme (ACE) inhibitors are also effective as sole therapy in many patients with essential ...
Zubrow A B - - 1989
The circulating levels of vasopressin, catecholamines and renin activity before, during and following a 10-20% fall in mean arterial blood pressure induced by sodium nitroprusside were measured in six chronically catheterized lambs during the first week of life. No significant changes in pHa, PaO2, PaCO2, Plasma sodium or osmolality were ...
Ehmke H - - 1989
We investigated the influence of a stimulation of intrarenal alpha 1-adrenoceptors on the relationship between renin release and renal artery pressure in 8 conscious, chronically instrumented dogs receiving a normal salt diet. Renin stimulus-response curves were determined by a stepwise reduction of renal artery pressure down to 70 mm Hg ...
Rosenfeld J B - - 1989
The most important component of the renal-body fluid feedback is renal pressure natriuresis which through sodium and water excretion stabilizes arterial pressure. The chronic effects of angiotensin II in regulating the pressure natriuresis was studied in dogs by the Guyton school. Renal perfusion was either permitted to increase or was ...
Lind L - - 1989
Patients with essential hypertension, in particular those with low plasma renin activity (PRA), are reported to have lowered plasma-ionized calcium and elevated parathyroid hormone levels. In this study 1 microgram alphacalcidol (1 alpha-hydroxy-vitamin D3) was given in a double-blind, placebo-controlled fashion over four months to 39 subjects with mild to ...
Fallo F - - 1988
The aim of this study was to assess the cardiovascular and hormonal responses to 1-desamino-8,D-arginine vasopressin (DDAVP) in hypertensive patients before and after non-selective beta-blockade. We infused DDAVP at 400 ng/kg body weight for 10 min in nine subjects with mild essential hypertension before and 14 days after administration of ...
de Leeuw P W - - 1988
Previous experiments have shown that blockade of intrarenal alpha 2-adrenoceptors will cause a rise in renin secretion. Therefore, we designed the present study to explore whether this could be due to noradrenaline being released by a prejunctional mechanism and stimulating post-junctional beta 1-adrenoceptors. Two groups of patients in whom diagnostic ...
Yoshida S - - 1988
The present study was designed to investigate the involvement of the renal nerve in glucocorticoid hypertension and to assess the role of the renin-angiotensin system in dexamethasone-induced hypertension. The elevated blood pressure in dexamethasone treated rats showing a significant increase in plasma renin concentration (PRC) and activity (PRA) was attenuated ...
Rector W G WG - - 1988
We measured total blood volume (125I-albumin), cardiac dimensions and function (echocardiography with Doppler), systemic hemodynamics (blood pressure and pulse), and plasma renin activity and norepinephrine levels in cirrhotic patients with and without ascites to assess the likelihood that either diminished central or arterial filling is the stimulus to sodium retention. ...
Hebden R A - - 1988
The effect of hypotensive haemorrhage on blood pressure recovery was compared in saline- and streptozotocin-injected rats. Absolute plasma volumes (and calculated blood volumes) were not different between the two groups. After haemorrhage of similar volumes at similar rates, there were no significant differences in the recoveries in blood pressures or ...
Hasser E M - - 1988
This study examined the contribution of each primary pressor system to resting arterial pressure and the ability of each to maintain pressure in the absence of the other systems in conscious dogs. In dogs with intact carotid sinus baroreflexes, ganglionic blockade (GB) reduced blood pressure by 13 +/- 3 mmHg, ...
Volpe M - - 1988
In a previous paper, we showed that during a long-term, moderate restriction in sodium intake, sympathetic nervous system activity was only transiently stimulated, whereas a sustained rise of plasma renin activity occurred. However, the contribution from stimulation of the renin-angiotensin system in the maintenance of blood pressure homeostasis during a ...
Bugge J F - - 1988
To examine the relationship between renal release of the prostaglandins E2 (PGE2) and I2 (PGI2) and renin during autoregulatory vasodilation, experiments were performed in anaesthetized dogs with denervated kidneys. Autoregulatory vasodilation was induced by reducing renal arterial pressure (RAP) or by raising ureteral pressure in steps. During progressive renal arterial ...
Grassi G - - 1988
Studies that have examined the cardiopulmonary receptor control of circulation in hypertension have produced conflicting results. In 10 normotensive subjects and in age-matched essential hypertensive subjects without (n = 10) or with left ventricular hypertrophy (n = 12), as well as in seven subjects of the latter group restudied after ...
Rouleau J L - - 1988
The objective of this study was to assess the hemodynamic and neurohumoral (plasma renin activity, aldosterone, epinephrine, norepinephrine, vasopressin, and atrial natriuretic peptide) determinants of systemic vascular resistance in 35 patients with stable congestive heart failure. In the supine position, although activation of the various neurohumoral systems tended to occur ...
Julius S - - 1988
The abnormal distribution of plasma renin values described in established essential hypertension are also found in patients with very early, borderline hypertension. In established hypertension, renin values have been used to draw inferences about the pathophysiology of blood pressure elevation. Within this concept, the low-renin state is considered a volume-dependent ...
Gregory L C - - 1988
Previous studies have suggested that the inhibition of renin secretion by acute administration of vasopressin in conscious dogs results from a reflex reduction in renal nerve activity. In the present investigation, this hypothesis was tested by studying the effect of total baroreceptor denervation or selective low pressure baroreceptor denervation on ...
Porter J P - - 1988
The sympathetic nervous system is an important factor that can induce increased renin secretion by the kidney. In recent years, the notion has arisen that the sympathetic nervous system may also function to set the level of responsiveness of the kidney to nonneural stimuli for renin secretion. However, evidence in ...
Riegger A J - - 1988
Neurohumoral vasoconstrictor systems are activated in heart failure and influence left ventricular function by modifying pre- and afterload. The renin-angiotensin system, sympathetic nerve activity and vasopressin have all been implicated as mechanisms of vasoconstriction. We investigated the vasoconstrictive action of vasopressin by blocking its vascular receptors by a specific antagonist ...
Shibutani Y - - 1988
Plasma renin activity (PRA) was determined in a group of 610 Japanese schoolchildren aged 10-14 years in order to investigate the relationship between PRA distribution and a family history of hypertension. Plasma renin activity was higher in the subjects with a family history of hypertension (FH+) than in those without ...
Fine B P - - 1988
Clinical and experimental studies suggest an association between low-level lead exposure and hypertension. This association was investigated in six 3-month-old dogs who were randomly paired with their littermates. The daily oral dose of lead acetate was 1.0 mg Pb/kg body wt for 5 months; the controls received equimolar sodium acetate. ...
Lin H B - - 1988
We analyzed the changes in control of renal hemodynamics and renin release resulting from hyperkalemia in the rabbit. Plasma potassium activity was maintained at a controlled elevated level by intravenous infusion of KCl. The potassium activity of the control group (n = 23) averaged 3.20 +/- 0.06 meq/l and that ...
Levenson J - - 1988
The simultaneous acute effects of converting enzyme inhibition by intravenous enalaprilat on the circulating renin-angiotensin system and on the brachial artery were studied in 12 hypertensive patients by a double-blind comparison with saline effects in 14 hypertensive patients. The brachial artery was investigated in terms of arterial section (measured by ...
Ferrario C M - - 1988
In this article we summarize studies of the hemodynamic and endocrine effects of desoxycorticosterone (DOC)-induced hypertension in dogs and also review new data of the action of this steroid on baroreceptors. The hemodynamic effect of subcutaneous injections of DOC to dogs, without supplementation of salt in their diet, consisted of ...
Fuji Y - - 1988
A newly produced calcium entry blocker, KW3049 (Kyowa Hakko, Tokyo, Japan), which maintains its antihypertensive action for greater than 24 h, was administered orally once daily to 12 subjects (5 normotensive, 7 hypertensive) for 12 days. To elucidate its hypotensive efficacy and mechanisms of action, daily changes in blood pressure ...
Gregory L C - - 1988
Previous studies have provided evidence that vasopressin plays an important role in blood pressure regulation during water deprivation. However, these investigations have been complicated by reflex compensatory increases in cardiac output and renin secretion. The aim of the present study was to investigate the effect of blockade of the vasoconstrictor ...
Kleinert H D - - 1988
We have designed a novel class of potent (0.3-7 nM) renin inhibitors which contain a dihydroxyethylene replacement for what is formally the Leu10-Val11 amide bond. Good potency (0.6 nM), water solubility (greater than 10 mg/ml at 37 degrees C), stability toward degradation by chymotrypsin (t1/2 = 820 min), and in ...
Grassi G - - 1988
Cardiopulmonary receptors have been shown to modulate renin release in animals. However, their involvement in reflex control of renin in humans has never been unequivocally established. This report reviews data on the effects on plasma renin activity of maneuvers (lower body negative pressure and passive leg raising) that reduce and ...
Ueno Y - - 1988
We characterized the hemodynamic and endocrine changes associated with the evolution of steroid-induced hypertension in conscious, trained, instrumented dogs given intramuscular injections of deoxycorticosterone (DOC) pivalate on Days 1 (20 mg/kg) and 14 (10 mg/kg) of the study. Because hypertension could be produced in these dogs without salt loading and ...
Sasaki S - - 1988
The hypotensive mechanism of percutaneous transluminal dilatation (PTD) in renovascular hypertension due to bilateral renal artery was investigated in two patients. Blood pressure was monitored continuously before, during and after PTD by use of a new automated blood pressure monitoring device based on finger volume-oscillometry. Plasma renin activity was measured ...
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