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Results 501 - 550 of 1260
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Cipolla C M - - 1990
In congestive heart failure (CHF), hemofiltration is associated with an obvious decrease in circulating norepinephrine. This method was used for investigating the mechanisms whereby plasma norepinephrine is increased in chronic CHF. In 23 cases of advanced CHF, hemofiltration (2,983 +/- 1,228 ml) lowered plasma norepinephrine by 515 +/- 444 pg/ml. ...
Francis G S - - 1990
The increased neuroendocrine activity in patients with congestive heart failure appears to be a generalized attempt to maintain blood pressure at the expense of reduced cardiac performance and salt and water retention. It is likely that baroreceptor dysfunction contributes to increased sympathetic nervous system activity in patients with congestive heart ...
Evans R R - - 1990
Renin and catecholamine levels were determined in patients with mild to moderate hypertension before and after treatment with sustained release diltiazem or captopril and were correlated with the blood pressure response to these antihypertensives. Eight weeks of treatment with either agent led to equal decreases in both systolic and diastolic ...
Holman N D - - 1990
A 55-year-old man developed renovascular hypertension that was characterized by high plasma renin activity. This was accompanied by nephrotic range proteinuria. Treatment with nifedipine and furosemide lowered the blood pressure to normal values, but proteinuria persisted. However, treatment with an ACE-inhibitor brought resolution of the proteinuria, suggesting a role for ...
Baker K M - - 1990
We have recently shown that the octapeptide angiotensin II is a potent stimulus of protein synthesis and growth in cultured cardiomyocytes. The present study was performed to determine if the renin-angiotensin system was involved in regulating cardiac cell growth in vivo. The pressure-overload cardiac hypertrophy model that develops in abdominal ...
Resnick L M - - 1990
Although altered cellular calcium handling plays a critical role in the pathophysiology of hypertension, little attention has been focused on the impact of calcium regulating hormones on this process. Recent research provides evidence that parathyroid hormone, calcitonin, 1,25-dihydroxyvitamin D, as well as newly described factors such as calcitonin gene-related peptide ...
Dimsdale J E - - 1990
This study examines the relationship between renin levels and physiologic reactivity to stressors. Seventy-five normotensive and mildly hypertensive men were studied on a high salt diet (200 mEq/day Na) and on a low salt diet (10 mEq/day Na). Renin, plasma catecholamines, heart rate, and blood pressure were examined at rest, ...
Ritchie C M - - 1990
The pathogenesis of the hypertension associated with Cushing's syndrome and with acromegaly is poorly understood. We have investigated the possible roles of sodium retention, activation of the renin-angiotensin system and increased sympathetic nervous system activity in untreated patients. In 11 patients with Cushing's disease, seven of whom were hypertensive, total ...
Gadsbøll N - - 1990
The temporal blood pressure course and the diurnal profile of the renin-angiotensin system were examined in 13 patients with essential hypertension receiving hydrochlorothiazide and enalapril once daily. Blood samples were taken and blood pressure was measured before the habitual morning dose of hydrochlorothiazide and enalapril (at 8.00 a.m.) and at ...
Rosenberg S H - - 1990
Incorporation of nonreactive polar functionalities at the C- and N-termini of renin inhibitors led to the development of a subnanomolar compound (21) with millimolar solubility. This inhibitor demonstrated excellent efficacy and a long duration of action upon intravenous administration to monkeys. While activity was also observed intraduodenally, a comparison of ...
Gould A B - - 1990
Positive correlation between systolic blood pressure and plasma renin substrate was demonstrated in Wistar-Kyoto rats when plasma renin substrate was reduced to within a range of 18 and 88% of control values with varying amounts of ramipril. When ramipril was given in amounts that had a maximum effect on systolic ...
Weber M A - - 1990
To evaluate the participation of the renin-angiotensin system in sustaining hypertension, we administered the specific dipeptide renin inhibitor enalkiren (A-64662) to 18 patients with essential hypertension. Ascending intravenous bolus doses (0.03, 0.1, 0.3, and 1.0 mg/kg) of the inhibitor were each given at 45-minute intervals to patients maintained on an ...
Fitzpatrick M A - - 1990
The effects of renin inhibition have not previously been documented in established heart failure (HF). Accordingly, we investigated the acute hemodynamic and hormonal effects of a renin inhibitor (EMD 52297) in an ovine model of HF induced by rapid ventricular pacing (LVP). In seven sheep, recordings were made for 1 ...
Narasimhan C - - 1990
We report a young male with sickle cell trait who developed severe hypertension and splenic infarction soon after travel to a high altitude. Hypertension persisted for three days after a diagnostic laparotomy. His blood pressure then continued to be normal over the next one and a half years. Red cell ...
Carr A A - - 1990
This study was designed to test the hypothesis that peripheral vein plasma renin activity is a determinant of the magnitude of the hypotensive effect of the calcium antagonist Isradipine when given to mild to moderately severe essential hypertensives. There was significant relationship between plasma renin activity and blood pressure reduction ...
Bock H A - - 1990
A new technique is presented that allows the measurement of the renin secretion rate of single rabbit glomeruli during in vitro perfusion at controlled afferent arteriolar perfusion pressure. Rabbit glomeruli with intact afferent arteriole and Bowman's capsule are obtained by microdissection and cannulated with a pipette system that allows continuous ...
Mullins J J - - 1990
PRIMARY hypertension is a polygenic condition in which blood pressure is enigmatically elevated; it remains a leading cause of cardiovascular disease and death due to cerebral haemorrhage, cardiac failure and kidney disease. The genes for several of the proteins involved in blood pressure homeostasis have been cloned and characterized, including ...
Riegger A J - - 1990
In heart failure, neurohumoral factors are activated, influencing ventricular performance by modulation of pre- and afterload. There is evidence from experimental models of congestive heart failure that in the early phase of the disease the sympathetic nervous system and atrial natriuretic peptide secretion are activated. Despite a reduction in cardiac ...
Shepherd J T - - 1990
The cardiovascular reflexes have the key role in the rapid adjustments of the circulatory system in response to daily stresses such as standing and muscular exercise. Arterial and cardiopulmonary mechanoreceptors continuously signal to the cardiovascular centers in the brain the moment to moment pressure changes in the larger arteries, atria ...
Schaffer L W - - 1990
In order to investigate the hypotensive mechanisms of action of peptide renin inhibitors, blood pressure responses to five renin inhibitors were compared with those to the angiotensin converting enzyme inhibitor, enalaprilat, in conscious African green and rhesus monkeys. (3S-4S)-4-amino-5-cyclohexyl-3-hydroxy pentanoic acid (ACHPA)-containing renin inhibitory peptide (ACRIP) and enalaprilat both decreased ...
Nobiling R - - 1990
It is well established that renin release from the juxtaglomerular epithelioid cells in the media of the afferent arteriole strongly depends on the mean renal perfusion pressure, whereas a possible influence of the pulsation of blood pressure on renin release has only occasionally been investigated, and the results are contradictory. ...
Kawabe H - - 1990
To assess the dopaminergic regulation of blood pressure and the renin-angiotensin-aldosterone system in fourteen essential hypertension (EHT) and six normotensives (NT), intravenous injections of 10 mg of the dopamine antagonist, metoclopramide (MCP), were given. Essential hypertension patients were divided into two subgroups according to the basal values of plasma renin ...
Gibbons G H - - 1990
The pathogenesis of hypertension is associated with a remodeling of vascular structure. Follow has postulated that the decreased luminal area and thickened medial layer in hypertensive vessels enhances the vasoconstrictive response to vasoactive agents. It is hypothesized that this increase in vascular reactivity may serve to perpetuate hypertension. A growing ...
Duprez D - - 1990
We report a case of a 25 year old man referred to our department because of a blood pressure of 162/122 mmHg, found during a general physical examination. A renal renin-secreting tumour was found to be the cause of the hypertension. It had a diameter of 4 cm and was ...
Boedy R F - - 1990
Systemic hypertension has been associated with extracorporeal membrane oxygenation (ECMO) applied in neonatal respiratory failure. To determine the incidence of ECMO-related hypertension, we reviewed blood pressure measurements from indwelling aortic catheters in 31 infants consecutively placed on ECMO. Systemic hypertension (systolic blood pressures greater than 100 mm Hg for 4 ...
Mayer N - - 1990
This study examined the impact of enflurane (3%) on the hemodynamic and humoral defense mechanisms in a canine model of hemorrhagic shock. In order to obtain reasonable reference values with confounding influences of anesthesia and recent surgical preparation, the dogs were chronically instrumented 8-10 days prior to the experiments enabling ...
Alper R H - - 1990
The effect of the selective 5-HT2 agonist (+-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI) on arterial pressure (AP), heart rate (HR), renal blood flow (RBF) and plasma renin activity (PRA) was determined in conscious rats. DOI increased AP and PRA, but decreased HR and RBF. All responses to DOI were abolished by central (LY ...
Kunes J - - 1990
1. The influence of chronic forelimb immobilization enforcing movement in upright position on blood pressure was studied in monkeys. 2. In the course of 6 months all animals subjected to immobilization became hypertensive due to a parallel increase of systolic and diastolic pressure by about 30%. The hypertension was demonstrable ...
Oliver J R - - 1990
We determined the relationships during hemorrhage between nominal blood volume (BV) and 1) plasma arginine vasopressin (AVP), 2) plasma renin activity (PRA), and 3) mean arterial pressure (MAP). Conscious rabbits were studied under normal conditions and during total autonomic blockade (TAB) at bleeding rates of 2 and 4 ml/min. Normally, ...
Johnston C I - - 1990
Knowledge of the structure, function and distribution of the components of the renin-angiotensin-aldosterone system (RAS) and the integrated physiological role of this hormonal system is rapidly increasing, although many questions remain unanswered. The primary structure and localisation of RAS such as renin, prorenin, angiotensinogen, angiotensin-converting enzyme (ACE) and the angiotensins ...
Kurtz A - - 1990
Renin secretion from renal juxtaglomerular cells is controlled by the intrarenal blood pressure, sodium chloride load of the organism, sympathetic nerve activity, and a number of hormones. The mechanisms by which these parameters exert their effects are not well understood. However, it is reasonable to assume that they act via ...
Reid J L - - 1990
Converting enzyme inhibitors, alone or in combination, are a safe and effective treatment for many hypertensives. However, the range of responses varies between individual patients and it has been claimed that there are two or three phases to the response. Pretreatment plasma renin (as an indication of activation of the ...
Ferrario C M - - 1990
Current leading theories of the mechanisms of essential hypertension include the participation of the renin-angiotensin-aldosterone system (RAS). Recent advances provide means for a critical reassessment of this system in the physiology and pathology of hypertension. The expression of the proteins of the RAS in organs other than the kidneys suggests ...
Donnerer J - - 1989
(1) The influence of capsaicin-sensitive afferent neurones on the regulation of blood pressure by reflex noradrenergic responses and by activation of the renin-angiotensin system was investigated in the rat anaesthetized with pentobarbital. (2) Lowering the pressure in the carotid sinus through unilateral carotid occlusion caused a reflex rise in mean ...
Beattie E C - - 1989
Hydroxy-ethylene dipeptide analogues (Leu[CH(OH)-CH2]Leu and Leu[CH(OH)-CH2]Val) of human substrate peptides are potent in vitro inhibitors of rat renin with IC50 values as low as 0.8 nmol/l. When given to renal hypertensive rats they lower blood pressure and suppress both plasma renin and angiotensin II. There was a divergence between the ...
Morganti A - - 1989
We measured arterial pressure and plasma renin activity throughout the first week after a technically successful percutaneous transluminal renal angioplasty (PTRA) in 12 patients with hypertension and unilateral renal artery stenosis. Mean arterial pressure fell from 126 +/- 4 to 105 +/- 3 mmHg within 1-2 days of PTRA and ...
Murakami E - - 1989
The effect of brain glutathione reductase activity on blood pressure regulation was investigated. The intravenous administration of the glutathione reductase inhibitor, nitrofurantoin (0.1-0.3 mg/rat), to seven normotensive Wistar rats caused dose-dependent rises in blood pressure and the heart rate (delta mean blood pressure 17 +/- 1 mmHg; delta heart rate ...
Nozawa K - - 1989
This study examined the role of the lipoxygenase (LO) pathway in the maintenance of hypertension in rats with two-kidney, one clip (2K,1C) Goldblatt hypertension. A single dose of the lipoxygenase blocker phenidone was injected intraperitoneally to 2K,1C rats during the early phase (14 days) of the development of hypertension (mean ...
Donnelly R - - 1989
1. This study investigates aspects of the pharmacokinetics, pharmacodynamics and concentration-effect relationships in 10 patients with essential hypertension during acute and chronic treatment with doxazosin, an alpha 1-adrenoceptor antagonist. 2. Following the first dose of doxazosin (2 mg) there were significant reductions in blood pressure, increases in heart rate and ...
Imanishi M - - 1989
To clarify the role of renal prostanoid in hyperreninemia and high blood pressure in human renovascular hypertension, we measured prostaglandin E2 and renin activity in renal venous and abdominal aortic plasma before and after the intravenous administration of the cyclooxygenase inhibitor, aspirin DL-lysine. Subjects were six patients with unilateral renovascular ...
Romero J C JC Department of Physiology and - - 1989
Because pressure-related natriuresis may be central to the regulatory role of the kidney on blood pressure, it is important to understand the relationship of humoral systems involved in the control of renal hemodynamics and tubular function. The preglomerular endothelial synthesis of prostaglandin I2 and endothelium-derived relaxing factor seem to modulate ...
Pedrinelli R - - 1989
Venous distensibility, forearm blood flow (FBF, plethysmographic technique), systemic blood pressure (BP), and derived forearm vascular resistances were measured in 11 borderline-mild hypertensive, otherwise healthy male subjects for a 24-h period during either placebo or transdermally delivered nitroglycerin (NTG 10 mg/24 h). The drug caused arteriolar and venular forearm vasodilation ...
Licht M R - - 1989
We compared the effects of infused norepinephrine (NE) to another alpha-adrenergic agonist, phenylephrine, in order to understand better the influence of circulating NE on plasma renin activity (PRA) in man. In matched groups of normotensive men, NE (80 ng/min/kg) or phenylephrine (800 ng/min/kg) raised blood pressure by 15 to 20 ...
Reid J L - - 1989
The factors determining the acute and long-term response to calcium antagonists have been studied in controlled trials in essential hypertension. The importance of dose and plasma level in determining the response has been confirmed. The blood pressure response has been modelled and mathematically described, with drug concentrations related to blood ...
Lee J - - 1989
Six forms of renin, distinguishable by their isoelectric focusing characteristics, are found in rat kidney and plasma (forms 1-6, form 1 having the most basic pI). To test the hypothesis that high blood pressure in stroke-prone spontaneously hypertensive rats (SHRSP) is associated with a particular fraction of the renin forms, ...
Hirsch A T - - 1989
The purpose of this study was to determine the effects of sustained unloading of baroreceptors in humans. The regional hemodynamic responses to lower body negative pressure (LBNP) were determined in 20 normal subjects. LBNP at -10 mmHg for 1 h decreased central venous pressure (CVP) without affecting blood pressure or ...
Woods L L - - 1989
Utero-placental ischemia is known to cause systemic hypertension in various species, but the mechanisms are unknown. These studies were designed to test the hypothesis that the increased systemic arterial pressure that occurs during reduced utero-placental perfusion pressure is mediated by the renin-angiotensin system, possibly due to release of renin or ...
Yang H M - - 1989
We examined the relationship between plasma renin activity (PRA) and renal arterial pressure (RAP) during 1) control conditions, 2) acute, and 3) chronic intravenous epinephrine (EPI) infusion (125 ng.kg-1.min-1). In eight conscious uninephrectomized dogs maintained on a normal sodium intake, the renin stimulus-response curve (RSRC) was determined by a stepwise ...
Mohanty P K - - 1989
Baroreflex modulation of forearm vascular resistance (FVR) has been reported to be abnormal in patients with congestive heart failure (CHF). However, the neurohumoral mechanisms for this impairment are not defined. We assessed the responses of arterial pressure, FVR, plasma norepinephrine, and plasma renin activity to lower body negative pressure in ...
Deray G - - 1989
In a previous study we discovered that the adenosine receptor antagonist, caffeine, increases plasma renin activity and blood pressure in renin-dependent renovascular hypertension. The purpose of the present investigation was to determine whether methylxanthines augment the increase in renin secretion induced by a reduction in renal perfusion pressure and, if ...
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