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Query: UMLS:C0042373 (vascular disease)
 17,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To characterize the renin-angiotensin system in the Aoki-Okamoto spontaneously hypertensive rat (SHR) more fully, serial measurements of plasma renin activity (PRA), plasma renin concentration (PRC), renin reactivity (as relative index of circulating modifiers of the renin reaction) and renin substrate concentration were made in 6- to 64-week-old SHR and in age-matched Wistar-Kyoto normotensive rats (WKY). In the evolving phase of SHR hypertension (6 and 13 weeks of age), PRA was comparable to WKY control values, whereas mature SHR with established hypertension developed, between 13 and 35 weeks of age, a high-PRA state persisting through 64 weeks of age. In 64-week-old SHR, increased plasma volume (3.54 +/- 0.91 in SHR vs. 3.18 +/- 0.90 ml/100 g body weight in WKY, p less than 0.025), together with increased PRA (24.9 +/- 3.8 in SHR vs. 13.1 2.2 ng AI/ml plasma/hr in WKY, p less than 0.025), suggest that volume decrease cannot explain increased PRA. In 42-week-old SHR, PRA was incompletely suppressed by deoxycorticosterone acetate plus 1% saline orally for 4 days: 4.9 +/- 1.2 in SHR vs. 0.6 +/- 0.8 ng angiotensin I/ml plasma/hr in WKY, p less than 0.001. Modestly increased renin reactivity of plasma was observed in SHR at all ages studied, supporting the ubiquity of increased circulating accelerators (or decreased inhibitors) of the renin reaction in hypertensive states. However, elevated renin reactivity did not account for the transition from normal to high PRA observed in mature SHR, nor did renin substrate concentration, which was consistently lower in SHR than in age-matched WKY. Temporal patterns of, and strain differences in PRA were closely paralleled by variations in PRC but not by other reaction components. Significant elevation of serum creatinine in old SHR support the presence of renal injury. We conclude that PRA and PRC are normal in evolving SHR hypertension and progress to abnormally elevated levels after hypertension is established. We postulate that "high-renin" hypertension may develop as a consequence of the hypertensive state per se, perhaps due to nephrosclerotic vascular disease.
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PMID:Serial renin-angiotensin studies in spontaneously hypertensive and Wistar-Kyoto normotensive rats. Transition from normal- to high-renin status during the established phase of spontaneous hypertension. 39 38

Malignant hypertension was induced in Sprague-Dawley rats by a complete aortic ligation above the left renal artery. The effects of saline (0.9% NaCl) administration on the development and course of the malignant hypertensive vascular disease were studied and the treated rats were compared to non-saline-treated animals and to sham-operated controls in the early and chronic phases of the disease. In the early phase, blood pressure, hematocrit, body weight, and hypertensive vascular disease were characteristic of the malignant hypertensive process and were without significant difference in saline- and non-saline-treated animals. In contrast, the sham-operated rats remained normotensive and did not present abnormal histological findings. Plasma renin activity although decreased in the hypertensive saline-treated animals was not suppressed. In the chronic phase, NaCl administration caused an average increase of 40 g body weight during the 1-wk period this solution was given, but did not result in any improvement in blood pressure levels and vascular disease in treated rats compared to non-saline-treated animals.
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PMID:Effects of sodium chloride on early and chronic phases of malignant hypertension in rats. 44 88

Hypertension is associated with an increased incidence of generalized vascular disease. Antihypertensive drug therapy, while decreasing overall mortality due to cerebral hemorrhage, myocardial hypertrophy or renal failure, paradoxically does not appear to reduce the incidence of coronary atherosclerosis. This study investigates whether the drugs, as a possible side effect, may have an adverse influence on the development of atherosclerotic plaques. Groups of rabbits were fed an atherogenic diet containing 1% cholesterol for 12 weeks. Two commonly used antihypertensive agents (methyldopa and chlorthalidone) were added to the diet of some groups at levels of 100 mg and 10 mg per day respectively. No significant increase in total atherosclerotic plaque area was produced by either of the drugs tested singly or in combination. Plasma renin levels were only mildly elevated and in this experimental system there was no correlation between renin activity and atherosclerotic plaque intensity. There is thus no evidence from this study that antihypertensive drugs have any adverse effects on atherosclerotic plaque formation. While the ineffectiveness of these drugs against coronary atherosclerosis may indicate that normalization of pressure cannot arrest changes already initiated, it also supports the possibility that association of atherosclerosis with hypertension may be symptomatic of a common underlying defect not correlated by normalizing blood pressure.
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PMID:Anti-inflammatory agents in experimental atherosclerosis. Part 2. Failure of antihypertensive drugs to exacerbate atherosclerotic plaque formation. 83 50

1. The syndrome of malignant hypertension in man and animals has three fundamental components: high blood pressure, activation of the renin-angiotensin system and the rapid development of necrotizing arteriolar disease. 2. The high blood pressure can be associated with different conformations of the arteriolar microcirculation. The emergence of an arteriolar reaction pattern characterized by the formation of focal dilatations, with intervening constricted segments, is of fundamental pathophysiological importance. 3. Activation of the renin system is reflected in an increased renin secretion rate from the kidneys and an increased rate of angiotensin II generation in the pulmonary vascular bed. 4. The crucial pathogenetic process, leading eventually to severe arteriolar wall damage, is a penetration of plasmatic macromolecules into the wall of distended arteriolar segments, as observed in states of severe experimental hypertension. 5. Renin can induce vascular disease, but hypersecretion of renin is not a necessary condition for the development of hypertensive arteriolar necrosis.
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PMID:The renin-angiotensin system and the pathogenesis of vascular disease in malignant hypertension. 107 5

In conclusion, patients on chronic maintenance dialysis have an increased incidence of death from cardiovascular disease. Hypertension plays a major role, and these patients must be carefully monitored for complete control of blood pressure. Adequacy of ultrafiltration to maintain normal extracellular volume is an essential part of the dialytic treatment. Hypertensive patients should be screened for excessive renin secretion because of its possible role in unresponsive hypertension in patients on dialysis. Nephrectomy should be used when necessary, where dialysis and antihypertensive medication have not adequately controlled blood pressure. Patients must be monitored for the presence of pericardial disease to avoid subsequent pericardial effusion and the development of constrictive pericarditis with its adverse effect on myocardial function. When constrictive pericarditis is present, it obviously should be relieved by appropriate surgery. Efforts should be made to minimize cardiac output in hemodialysis patients. Whether or not routine transfusions to maintain a higher hematocrit are indicated is a question that cannot yet be answered. However, patients with marginal cardiovascular function who are accepted on hemodialysis and must have an arteriovenous shunt should be supported in any manner to minimize an increase in cardiac output. Early and aggressive treatment of known episodes of sepsis is important in the elimination of valvular endocarditis in this patient population. Perhaps one of the finer indicators of adequacy of hemodialysis will be K rate and peak immunoreactive insulin levels. Continued abnormality of these parameters may contribute to cardiovascular disease. Clearly, further study of the effect of abnormal carbohydrate metabolism on lipid metabolism is in order. Serum triglyceride, serum cholesterol and lipid electrophoretic pattern should be followed to evaluate the beneficial effects of drug therapy and changes in dialytic technique on the development of cardiovascular disease. Careful monitoring of calcium, phosphorus, bone films and parathyroid hormone levels is indicated to assess parathyroid status. The use of aluminum binders and parathyroidectomy to prevent vascular and myocardial calcification is important in the therapy of these patients. The use of cardiac catheterization, coronary artery arteriography, and possibly cardiac vascular repair, should be considered in the chronic hemodialysis patient with coronary artery disease if he is otherwise well. Adequacy of hemodialysis perhaps can be evaluated through its effect on all of the above parameters. Whether or not changes in artificial kidney treatments can correct the final vascular disease remains to be seen.
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PMID:Cardiovascular disease in uremic patients on hemodialysis. 109 1

Investigations for renal artery stenosis have been greatly facilitated by advances in imaging techniques. Intravenous digital subtraction angiography is now performed in all patients with progressive, drug-resistant hypertension associated with aorto-iliac lesions or with renal impairment induced by angiotensin-converting enzyme inhibitors. Yet the finding of hypertension with renal artery stenosis is not enough to make the diagnosis of renovascular hypertension, this term being reserved to hypertension reversible by revascularization. The selection of patients who may benefit from revascularization rests on urography to explore the excretory and endocrine functions of the ischaemic kidney, as well as on scintigraphy and measurement of renin levels in renal veins before and after administration of captopril. The functional data are completed by vascular exploration which helps in evaluating the usefulness and safety of revascularization: repercussions of hypertension on target organs and extension of the vascular disease to other territories. Revascularization as first-line treatment consists of percutaneous transluminal dilatation; surgery must be reserved to difficult cases, such as arterial obliteration or failed dilatation.
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PMID:[Renovascular hypertension: diagnostic and therapeutic strategy]. 141 Aug 86

Fifty-four children referred for investigation of hypertension had renovascular disease. In eight patients it was associated with neurofibromatosis, in three with idiopathic hypercalcemia of infancy, and in five cases it followed an arteritic illness. Fibromuscular dysplasia was the underlying abnormality in the majority of cases (46%). Twenty-six patients (48%) were first seen with accelerated hypertension; 38 children (70%) had bilateral renal arterial disease, and in 41 (76%), disease of the small intrarenal vessels was found. Renal vein renin ratios indicated unilateral disease in 31 cases; the results correlated with arteriography findings in 32 (62%) of 51 patients. Eleven children also had the middle aortic syndrome, and 9 of 16 patients, investigated by cerebral arteriography because of cranial bruits or focal neurologic signs, had cerebral vascular abnormalities. Twenty patients were treated surgically--10 by reconstructive procedures, 11 by nephrectomy or heminephrectomy, and 6 by transluminal angioplasty. Of these, 9 (45%) are normotensive with no treatment, 10 have a decreased requirement for antihypertensive drugs, and 1 had no improvement. Thirty-four patients were treated medically because of the extent of their disease; two patients have died of hypertensive complications. We conclude that renal vascular disease in children is often widespread, may be associated with intracerebral vascular disease, frequently affects both kidneys, including both intrarenal and extrarenal vessels, and is therefore not always amenable to surgical intervention and cure.
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PMID:Renovascular disease in childhood. 151 11

The heart is one of the major target organs that becomes secondarily involved with the unrelenting and progressive vascular disease of essential hypertension. As a result of this increasing afterload that is imposed upon the left ventricle, the ventricular chamber adapts structurally and functionally. Structural changes involve an increase in muscle mass that is achieved through left ventricular hypertrophy (in a manner similar to the arteriolar changes demonstrated by increased thickening). Unless antihypertensive therapy is interdicted in this disease process, left ventricular failure will ensue as the major cardiac hemodynamic consequence. Left ventricular hypertrophy is also associated with a risk that is independent of the pressure overload and hemodynamic risk. Although antihypertensive therapy will reduce from the hemodynamic alterations, only recently have epidemiological findings suggested that the independent risk of LVH may be reduced with pharmacological therapy. There are no data available to indicate just which agents may reduce the risk from LVH; but relatively recent studies seem to indicate that while all agents may reduce LVH with prolonged therapy only certain classes of agents will do so independent of their hemodynamic factors. Some of these agents, however, may impair cardiac function if arterial pressure is increased abruptly following therapeutic reduction of cardiac mass. Other agents may preserve normal function--or even may improve function. Among those classes of antihypertensive agents that reduce cardiac mass at least in part due to nonhemodynamic factors, are the angiotensin converting enzyme inhibitors, the calcium antagonists, and most adrenergic inhibitors. Evidence will be presented demonstrating the hemodynamic/structural dissociation of those pharmacological agents that reduce cardiac mass with short-term treatment in spontaneously hypertensive rats with left ventricular hypertrophy. Although centrally active adrenolytic, angiotensin converting enzyme (ACE) inhibitors, and calcium antagonists all reduce cardiac mass, their structural and cardiac functional effects differ greatly. Even within the ACE inhibitor group their effects vary--improving, impairing, or not changing the Frank-Starling relationships following reduction in left ventricular mass. We postulate great variability of cardiac intramyocytic penetrance of the pharmacological agents and their local intracellular effects on mitogenesis of the ventricular myocyte. The implications on cardiac function and therapy have vast potential. Therefore, current investigative areas involving new concepts of molecular biology of the cardiac myocyte may provide great promise to the quest of unraveling some of the newly postulated questions: What is the role of ionized intracellular calcium? Do the local renin-angiotensin systems in the cardiac and vascular myocyte participate in the development and regression of hypertrophy?(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Left ventricular hypertrophy: dissociation of structural and functional effects by therapy. 183 47

The interplays between calcium metabolic indices, retinal vascular status, plasma renin activity and blood pressure were examined in 67 patients with untreated essential hypertension. There was an inverse relationship between plasma ionized calcium and blood pressure (P = .002), whereas albumin-modified total serum calcium was directly related to blood pressure (P = .02). The plasma cyclic AMP level (P = .05) and the 24 h urinary excretion of cyclic AMP (P = .03) were also positively associated with blood pressure. Patients with vascular retinopathy had lower plasma ionized calcium concentrations (P = .01) and higher 24 h urinary cyclic AMP excretions (P = .05) than those without such changes, even when the differences in blood pressure, age, sex and body mass index were taken into account in analyses of covariance. Plasma renin activity did not interfere with the relationships between calcium metabolic indices and blood pressure, nor were there any associations between the renin status and the calcium metabolic indices. These findings suggest that a low concentration of plasma ionized calcium is an independent risk factor for vascular disease.
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PMID:Calcium metabolic indices, vascular retinopathy, and plasma renin activity in essential hypertension. 208 Oct 11

Physiological studies reported from our laboratory over the past several years have been reviewed and support epidemiological reports indicating that hypertensive cardiac and vascular disease runs a more severe course in the black patient. Although comparison of systemic hemodynamics failed to demonstrate that, for any level of arterial pressure, the magnitude of total peripheral resistance (which is the hemodynamic hallmark of hypertensive disease) differed between black patients and white patients, there are more subtle differences that were ascertained. Thus, although intravascular (plasma) volume contracts as arterial pressure and total peripheral resistance increase in both racial groups, this relation may differ quantitatively. At least in some black patients (43%), intravascular volume may be more expanded; in these patients, this relation is less closely correlated with the renopressor system (i.e., plasma renin activity). Moreover, these studies indicated that, at any level of arterial pressure, cardiac (left ventricular mass and posterior wall thickness) and renal hemodynamic involvement is more severe in the black patient. These findings point to important differences that operate in black patients and white patients with essential hypertension. With further study, these findings may be translated into more specific antihypertensive therapeutic implications for patients of both racial groups with essential hypertension.
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PMID:Hemodynamic differences between black patients and white patients with essential hypertension. State of the art lecture. 219 Sep 19


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