Search Results
Results 201 - 250 of 1266
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Safar Michel E - - 2003
The mechanism(s) of systolic hypertension in the elderly imply structural and functional alterations of the large artery wall. Clinical and experimental studies have shown that, in the long term, the renin-angiotensin system may act on the geometry and stiffness of the large artery wall independently of blood pressure level through ...
Andersen Steen - - 2003
BACKGROUND: Blockade of the renin-angiotensin system is the primary target in the treatment of diabetic kidney disease. Angiotensin II subtype 1 (AT1) receptor antagonists reduce albuminuria and lower blood pressure, but the initial time course of these effects after initiation of treatment is unknown. We evaluated the time course of ...
Li Yan Chun - - 2003
The renin-angiotensin system (RAS) plays a central role in the regulation of blood pressure, electrolyte, and volume homeostasis. Epidemiological and clinical studies have long suggested an association of inadequate sunlight exposure or low serum 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] levels with high blood pressure and/or high plasma renin activity, but the mechanism ...
Baumbach Gary L - - 2003
We examined the hypothesis that the renin-angiotensin system plays an important role in vascular remodeling (defined as reduced external diameter) during chronic hypertension. We measured pressure, diameter, and cross-sectional area of the vessel wall in maximally dilated cerebral arterioles in transgenic mice that overexpress both human renin and human angiotensinogen ...
Bader Michael - - 2002
The local generation of all components of the renin-angiotensin system (RAS) in the heart has been the basis for the postulation of a tissue RAS in this organ. Since angiotensin II is involved in the induction of cardiac hypertrophy and fibrosis the local generation of this peptide may be of ...
Varagic Jasmina - - 2002
In addition to the effect on arterial pressure, angiotensin II, the effector peptide of the renin-angiotensin system (RAS), exerts mitogenic and growth promoting effects on cardiac myocytes and non-myocytic elements; and both of these effects significantly contribute to the development and progression of hypertensive heart disease (HHD). The traditional concept ...
Oliveira Eduardo A - - 2002
We report a case of transitory hypertension associated with unilateral multicystic dysplastic kidney (MCDK). A newborn girl with MCDK, detected by prenatal ultrasonography, was conservatively treated and has been followed for 18 months at the Pediatric Nephrourology Unit (HC-Belo Horizonte, Brazil). Arterial hypertension was observed at about 4 months of ...
Zacharieva S - - 2002
BACKGROUND: Mechanisms of the vasoprotective effect of hormone replacement therapy (HRT) are not completely understood, and they may involve direct actions on blood vessels through modulation of endogenous vasoconstrictors and vasodilators. Most studies have focused on estrogen action on prostacyclin and nitric oxide, while insufficient data exist concerning the effect ...
Ng Tien M H - - 2002
Inhaled beta-agonists are commonly prescribed for the symptoms of exercise intolerance in heart failure despite a paucity of data regarding their safety and efficacy. This was a prospective, randomized, double-blind, double-dummy, placebo-controlled 14-day cross-over study to determine if chronic inhaled salmeterol therapy 84 microg every 12 hours improved pulmonary function ...
Laffer Cheryl L - - 2002
Little is known about essential hypertension in Hispanic Americans, despite the fact that they are the fastest-growing minority in the United States and have a disproportionate degree of hypertensive target organ damage. The authors studied 89 Caribbean Hispanic hypertensive patients who participated in six double-blind, randomized trials of antihypertensive agents. ...
Nyström H C - - 2002
The factors involved in maintenance and reversal of mean arterial blood pressure (MAP) in the chronic two-kidney one-clip hypertensive rat (2K1C-RHR) are still debated. The reduction in MAP after reversal of 2K1C hypertension has been ascribed either to release of a renal medullary depressor hormone (RMDH) or suppression of the ...
Li Yan Chun YC Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA. - - 2002
Inappropriate activation of the renin-angiotensin system, which plays a central role in the regulation of blood pressure, electrolyte, and volume homeostasis, may represent a major risk factor for hypertension, heart attack, and stroke. Mounting evidence from clinical studies has demonstrated an inverse relationship between circulating vitamin D levels and the ...
Gavras I - - 2002
A renin-angiotensin level that is inappropriately high for the systemic blood pressure and the state of sodium balance is now recognized to be one of the modifiable cardiovascular risk factors. Angiotensin acts both as a circulating hormone and as a locally acting paracrine/autocrine/intracrine factor. The adverse effects of angiotensin on ...
Pachori Alok S - - 2002
Our studies have established that a single intracardiac administration of the retroviral vector containing angiotensin II type I receptor antisense gene causes prolonged antihypertensive actions in the spontaneously hypertensive rat. These results suggest that antisense gene therapy is a conceptually valid strategy for the control of hypertension at the genetic ...
Peers A - - 2002
AIM: To examine cardiovascular, hormonal and other physiological responses of 2-month-old lambs to rubber-ring castration and tail docking. METHODS: Twenty-two male lambs, well accustomed to handling and prepared with femoral artery and jugular vein cannulae, were studied during a 5 h control period and, at least 2 days later, for ...
Wu Jiao-Hui - - 2002
Despite considerable evidence suggesting that hypertension contributes to the development and progression of atherosclerosis, the causative links remain unclear. We have tested the effects of chronic hypertension induced by suprarenal aortic constriction on the development of atherosclerosis in apolipoprotein E-deficient (Apoe-/-) mice. Compared with a sham operation, narrowing the aortic ...
Prescott Gary - - 2002
Both renin and its biosynthetic precursor, prorenin, are secreted into the circulation of mammals. Although the circulating levels of prorenin can exceed those of renin by as much as 100-fold in certain conditions, there is no evidence that prorenin contributes to the synthesis of circulating angiotensin peptide synthesis or increased ...
Stec David E - - 2002
Recent experimental evidence suggests a role for tissue renin-angiotensin systems in the development of hypertension. To test the importance of tissue renin-angiotensin systems in the development and maintenance of angiotensin II-dependent hypertension, we generated a transgenic model in which exon 2 of the human angiotensinogen gene is flanked by loxP ...
Hirota Nobuhisa - - 2002
This study was designed to delineate the involvement of phospholipase C (PLC) and phospholipase D (PLD) in transmural pressure control of renin synthesis and secretion. Primary cultures of rat juxtaglomerular (JG) cells were applied to a transmural pressure-loading apparatus for 12 hours, and the renin secretion rate (RSR), active renin ...
Metcalfe Beverly L - - 2002
Although traditional approaches are effective for the treatment and control of hypertension, they have not succeeded in curing the disease, and have therefore reached a plateau. As a result of the completion of the Human Genome Project and the continuous advancement in gene delivery systems, it is now possible to ...
Hargrave Barbara - - 2002
The purpose of this study was to determine (1) if the acute in vivo administration of cocaine and the cocaine metabolite ecgonine methyl ester (EME) activates the renin-angiotensin system (RAS) and alters cardiovascular function during pregnancy and (2) whether heart function is decreased in rabbits chronically exposed to cocaine or ...
Kondo S - - 2001
To clarify the possibility of a preventive effect of dietary vinegar on blood pressure, long-term administration of vinegar or the acetic acid to SHR was examined. As a result, it was observed that acetic acid itself, the main component of vinegar, significantly reduced both blood pressure (p<0.05) and renin activity ...
Klett C P - - 2001
Hepatic angiotensinogen secretion is controlled by a complex pattern of physiological or pathophysiological mediators. Because plasma concentrations of angiotensinogen are close to the Michaelis-Menten constant, it was hypothesized that changes in circulating angiotensinogen affect the formation rate of ANG I and ANG II and, therefore, blood pressure. To further test ...
Molinari C - - 2001
Distension of the uterus in anaesthetized pigs has been shown to cause a reflex regional vasoconstriction and an increase in plasma renin activity (PRA) through efferent sympathetic mechanisms which respectively involved alpha- and beta-adrenergic receptors. The present study was undertaken to determine the possible contribution of the activation of the ...
Sayago C M - - 2001
The interaction between nitric oxide (NO) and renin is controversial. cAMP is a stimulating messenger for renin, which is degraded by phosphodiesterase (PDE)-3. PDE-3 is inhibited by cGMP, whereas PDE-5 degrades cGMP. We hypothesized that if endogenous cGMP was increased by inhibiting PDE-5, it could inhibit PDE-3, increasing endogenous cAMP, ...
Nafz B - - 2001
Blood pressure variability is buffered by at least two mechanisms: the arterial baroreceptor reflex and nitric oxide (NO). Only recently is the importance of blood pressure variations on cardiovascular control being investigated. Here we report of a study performed in conscious dogs, in which renovascular hypertension was induced. Reduction of ...
Kubo T - - 2001
Brain renin-angiotensin system plays an important role in blood pressure regulation and is suggested to play a role in the development and maintenance of hypertension. To test the hypothesis that brain renin may play a significant role in hypertension in spontaneously hypertensive rats (SHR), phosphorothioated antisense oligodeoxynucleotides targeted to renin ...
Taugner F M - - 2001
Feline hypertrophic cardiomyopathy (HCM) is a disease of the ventricular myocardium, which may cause sudden death in cats, but neither the aetiology nor the effect on the circulation are well understood. Fourteen cats of either sex with naturally occurring HCM were studied post mortem. Their ages ranged from 9 months ...
Kantachuvesiri S - - 2001
A novel inbred rat model with inducible hypertension has been generated using a renin transgene under the transcriptional control of the cytochrome P450, Cyp1a1 promoter. The degree and duration of hypertension are regulated tightly by administration of the natural xenobiotic indole-3 carbinol and can be readily reversed. Induction experiments reveal ...
Henriksen J H - - 2001
BACKGROUND AND AIMS: Static and dynamic functions of the wall of large arteries are largely unknown in cirrhosis in vivo. The present study was undertaken to determine arterial compliance (COMP(art)) in relation to vasodilator and vasoconstrictor systems in patients with cirrhosis. In addition, vasoactivity was manipulated by inhalation of oxygen. ...
Pentz E S - - 2001
To distinguish the contributions of Ren1(d) and Ren2 to kidney development and blood pressure homeostasis, we placed green fluorescent protein (GFP) under control of the Ren1(d) renin locus by homologous recombination in mice. Homozygous Ren1(d)-GFP animals make GFP mRNA in place of Ren1(d) mRNA in the kidney and maintain Ren2 ...
Leung P S - - 2001
The classical concept of the renin-angiotensin system (RAS) is that of a blood-borne cascade, whose final and bioactive product, angiotensin II, plays an important endocrine role in the maintenance of blood pressure and electrolyte as well as fluid balance. In addition to this circulating RAS, there are an increasing number ...
Rosnes J S JS Department of Obstetrics and Gynecology, Perinatal Research Laboratories, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA. - - 2001
We hypothesized that renal denervation in mature ovine fetuses reduces renin mRNA response to 24 h of reduced renal perfusion pressure (RPP). Seven occluder (O) (132.4 +/- 1.2 days gestation) and six control (C) (131.5 +/- 1.2 days gestation) fetuses underwent left renal denervation. Postoperatively, O fetuses experienced 24 h ...
Kang A K - - 2001
We examined the effect of oral contraceptive (OC) usage on the renin angiotensin system (RAS) in two related experiments. In the first experiment, subjects were 34 healthy, normotensive, premenopausal women, 15 OC users and 19 OC nonusers, mean age 25 +/- 1 yr, ingesting a controlled sodium diet. We assessed ...
Cabrera J - - 2001
BACKGROUND: Some cirrhotic patients with tense ascites who undergo paracentesis develop a circulatory dysfunction syndrome, manifested by an increase in plasma renin activity. Recently, a significant inverse correlation between postparacentesis changes in plasma renin activity and systemic vascular resistance has been demonstrated in these patients, suggesting that peripheral arterial vasodilatation ...
Lerman L O - - 2001
The pathophysiological mechanisms responsible for maintenance of chronic renovascular hypertension remain undefined. Excess angiotensin II generation may lead to release of reactive oxygen species and increased vasoconstrictor activity. To examine the potential involvement of oxidation-sensitive mechanisms in the pathophysiology of renovascular hypertension, blood samples were collected and renal blood flow ...
Methot D - - 2001
Pharmacologic inhibition of the renin-angiotensin system (RAS) is a widely accepted and effective treatment for hypertension. However, in the past several years, much attention has been focused on additional roles of the RAS including the possibility that its end-product, angiotensin II, could elicit end-organ pathologies independent of its effect on ...
Witte K - - 2001
It is still a controversial issue whether different classes of antihypertensive drugs are equally effective in the regression of cardiac hypertrophy and associated complications. The present study compared the effects of prolonged treatment with the Ca2+-channel blocker amlodipine and the ACE inhibitor enalapril, respectively, in TGR(mREN2)27 rats (TGR), an animal ...
Engeli S - - 2001
Excessive accumulation of adipose tissue is associated with profound alterations in the cardiovascular system. including an increase in systemic blood pressure. It now appears clear that a central feature of obesity-associated hypertension is related to changes in sodium handling that may result from abnormalities in sympathetic nervous system activity, the ...
Leung P S - - 2001
The circulating renin-angiotensin system (RAS) plays an important role in the maintenance of blood pressure and fluid homeostasis. Recently, there has been a shift of emphasis from the circulating RAS to the local RAS in the regulation of individual tissue functions via a paracrine and/or autocrine mechanism. In fact, a ...
Akers W S - - 2000
Angiotensin II and norepinephrine (NE) have been implicated in the neurohumoral response to pressure overload and the development of left ventricular hypertrophy. The purpose of this study was to determine the temporal sequence for activation of the renin-angiotensin and sympathetic nervous systems in the rat after 3-60 days of pressure ...
Prescott G - - 2000
The activity of a local cardiac renin-angiotensin system (RAS) has long been suspected in the promotion of cardiac pathologies including hypertrophy, ischemia, and infarction. All of the components of the RAS cascade have been demonstrated to be synthesized within the heart with the possible exception of the first enzyme in ...
Murphey L J - - 2000
In humans, bradykinin contributes to the acute renin response after ACE inhibition. To further explore the role of endogenous bradykinin in human renin regulation, we determined the effect of HOE 140, a specific bradykinin B(2) receptor antagonist, on the renin response to 0.5 mg/kg i.v. furosemide in a randomized, single ...
Shin L H - - 2000
Along with the renin-angiotensin system, sympathetic stimulation may contribute to renovascular hypertension. The vasoactive peptide neuropeptide Y (NPY) is co-released with and potentiates the pressor effects of norepinephrine through the Y-1 receptor. NPY, by exaggerating sympathetic activity, may contribute to renovascular hypertension, possibly by augmenting adrenergic-mediated renin release. This was ...
Fleming S - - 2000
Malignant hypertension remains one of the life-threatening complications of blood pressure elevation. It is a clinico-pathological syndrome of severe blood pressure elevation combined with malignant vascular injury. This is a characteristic form of vascular damage, with two elements: fibrinoid necrosis and endarteritis proliferans. Although the morphology of these has been ...
Rossi A - - 2000
BACKGROUND: The evidence linking activation of the renin-angiotensin system with accelerated cerebro-vascular atherosclerosis remains controversial. We therefore prospectively investigated the relationships of plasma renin activity and aldosterone levels with carotid artery lesions (CAL) in essential hypertension. METHODS: We evaluated the prevalence and severity of CAL and the intimal-medial thickness (IMT) ...
Bonnet J M - - 2000
1. The present study was designed to assess the participation of extrarenal tissue renin-angiotensin systems (RAS) in pressure homeostasis in sheep. 2. The effect of the administration of an angiotensin II type 1 receptor antagonist (losartan; 30 mg/kg, i.v.) on mean arterial blood pressure (MABP) was investigated in eight intact ...
Varagic J - - 2000
BACKGROUND: Inhibition of nitric oxide (NO) synthase by L-arginine analogs is associated with elevation of blood pressure in rats. Because endothelium-dependent vasomotion in different vascular beds is not homogenous, the aim of this study was to characterize and compare regional hemodynamic responses in carotid, femoral, and renal vascular beds after ...
Welch W J - - 2000
Renovascular hypertension (RVH) results from occlusion of blood flow to either kidney, which stimulates renin release. Increased renin leads to a series of actions that rapidly leads to increased systemic blood pressure. Experimental renovascular hypertension is developed in animals by placement of a clip that occludes more than 50% of ...
Adamczak M - - 2000
Both leptin and the renin-angiotensin system (RAS) can influence the activity of the sympathetic nervous system, water and electrolyte metabolism as well as vascular remodelling, which are all involved in the regulation of arterial blood pressure. Thus leptin and the RAS may act together in the pathogenesis of essential hypertension. ...
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