Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An abnormal elevation in collagen concentration or myocardial fibrosis occurs in the hypertrophied left ventricle of the rat with renovascular hypertension (RHT). The structural nature and functional consequences of this fibrosis and the mechanisms involved in its appearance were reviewed for various phases of hypertrophy. Within days after the onset of renal ischemia, type I collagen messenger ribonucleic acid is expressed. An interstitial fibrosis follows, characterized by an increased dimension of existing perimysial fibers and the appearance of fibrillar collagen in spaces previously devoid of collagen, together with a perivascular fibrosis of intramyocardial coronary arteries. These expressions of myocardial fibrosis are associated with an increase in diastolic and systolic myocardial stiffness. Endomyocardial fibrosis serves to further increase diastolic stiffness while myocytes encircled by fibrillar collagen become atrophic. Each of these consequences of myocardial fibrosis reduce myocyte length-dependent force generation. At 32 weeks of RHT there is an obvious diastolic and systolic dysfunction of the ventricle together with heart failure that includes ventricular dilatation, wall thinning and reduced ejection fraction. The mechanisms involved in mediating fibrosis in RHT appear to be multiple. Myocyte necrosis and fibroblast proliferation have been associated with elevated circulating angiotensin II. Necrosis in RHT was not seen with captopril pretreatment or in the hypertension and hypertrophy that accompanied infrarenal aorta banding. An alteration in coronary artery permeability may be responsible for the perivascular fibrosis that is not seen with captopril pretreatment. Thus in RHT, the hemodynamic status of the ventricle determines myocyte hypertrophy while the elevation in circulating angiotensin II is responsible for the remodeling of nonmyocyte compartments, including the appearance of myocardial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Myocardial fibrosis and pathologic hypertrophy in the rat with renovascular hypertension. 213 51

With the exception of conventional angiography, no previously proposed screening test has the necessary sensitivity/specificity to guide further evaluation for correctable renovascular disease. Recently, renal duplex sonography has been suggested as a useful substitute in such screening for renovascular disease. This report analyzes our data collected over the past 10 months in evaluation of renal duplex sonography to examine its diagnostic value. The study population for renal duplex sonography validity analysis consisted of 74 consecutive patients who had 77 comparative renal duplex sonography and standard angiographic studies of the arterial anatomy to 148 kidneys. Renal duplex sonography results from six kidneys (4%) were considered inadequate for interpretation. This study population contained 26 patients (35%) with severe renal insufficiency (mean 3.6 mg/dl) and 67 hypertension (91%). Fourteen patients (19%) had 20 kidneys with multiple renal arteries. Bilateral disease was present in 22 of the 44 patients with significant renovascular disease. Renal duplex sonography correctly identified the presence of renovascular disease in 41 of 44 patients with angiographically proven lesions, and renovascular disease was not identified in any patient free of disease. When single renal arteries were present (122 kidneys), renal duplex sonography provided 93% sensitivity, 98% specificity, 98% positive predictive value, 94% negative predictive value, and an overall accuracy of 96%. These results were adversely affected when kidneys with multiple (polar) renal arteries were examined. Although the end diastolic ratio was inversely correlated with serum creatinine (r = -0.3073, p = 0.009), low end diastolic ratio in 35 patients submitted to renovascular reconstruction did not preclude beneficial blood pressure or renal function response. We conclude from this analysis that renal duplex sonography can be a valuable screening test in the search for correctable renovascular disease causing global renal ischemia and secondary renal insufficiency (ischemic nephropathy). Renal duplex sonography does not, however, exclude polar vessel renovascular disease causing hypertension alone nor does it predict hypertension or renal function response after correction of renovascular disease.
 ...
PMID:Renal duplex sonography: evaluation of clinical utility. 220 35

Dynamic I-123 Hippuran renal studies to measure furosemide response (FR) were performed in three groups of patients: 1) 57 patients with renovascular hypertension due to a poststenotic, ischemic kidney; 2) 23 patients with essential hypertension; and 3) 50 nonhypertensive patients with healthy kidneys (control group). FR was observed as renal parenchymal tracer washout within 10 minutes after the injection of 40 mg of furosemide. The retention index (RI) took into consideration the renal parenchymal tracer content before and 10 minutes after furosemide injection. In the control group, the FR was greater than 50% and the RI was less than 20. Patients with essential hypertension revealed no differences in the amounts of FR and RI compared with the control group. In renovascular hypertension, the FR was diminished and the RI was raised significantly. The values of FR and RI showed a good correlation to the degree of the renal artery stenosis before and after percutaneous transluminal angioplasty. It is concluded that the stimulation of diuresis with furosemide and its quantification represent an important additional step in the evaluation of dynamic I-123 Hippuran studies to detect renal ischemia.
 ...
PMID:Diminished response to furosemide in I-123 Hippuran renal studies of renovascular hypertension caused by unilateral renal artery stenosis. 220 82

The need to support the distal circulation during aortic crossclamping and the subsequent effects on hemodynamics and organ perfusion prompted our review of 51 patients who underwent repair of aneurysm of the descending thoracic aorta from 1983 through 1987. Forty-three patients had aneurysms originating distal to the left subclavian artery, and eight had aneurysms involving the distal aortic arch and the proximal descending aorta; 10 patients had emergency operation for aneurysm rupture. Three different techniques were used: Seventeen patients had left atrial-distal aorta arterial bypass with a centrifugal pump, 18 patients had a Gott shunt, and 16 patients had no circulatory support during aneurysm repair. Location and type of aneurysm, age, sex, diabetes, preoperative hypertension, and serum lipid levels were similar in the three groups. Duration of crossclamping was 54 +/- 12 minutes for left atrial-aortic assist, 45 +/- 5 for the shunt group, and 34 +/- 4 for patients without circulatory support. With crossclamping, all groups had similar and significant increases in heart rate (p less than 0.03). Proximal systolic blood pressure did not change during left atrial-aortic assist, but a transient increase occurred in patients with shunts (p less than 0.01), and a sustained increase occurred in patients without circulatory support (p less than 0.05). With crossclamp release, arterial pH and capillary pulmonary wedge pressure decreased significantly (p less than 0.05) in patients without shunt or bypass. Postoperative renal function did not vary significantly when circulatory support was used, but serum creatinine rose transiently in patients with unsupported aortic crossclamping. We conclude that support of the distal circulation during thoracic aortic crossclamping stabilizes hemodynamics and prevents systemic acidosis and renal ischemia. Further, our data suggest that the centrifugal pump may provide better protection than a passive shunt.
 ...
PMID:Circulatory support during crossclamping of the descending thoracic aorta. Evidence of improved organ perfusion. 235 21

The purpose of our article is to describe a patient with severe hypertension and moderate renal insufficiency, unstable angina, and a 6 cm abdominal aortic aneurysm. A previous aortogram had demonstrated severe bilateral renal artery stenoses. Cardiac catheterization demonstrated severe coronary disease. After cardiac catheterization acute renal failure and pulmonary edema requiring dialysis developed in the patient. In addition, evidence of impending myocardial necrosis developed. Because of the critical nature of the myocardial and renal ischemia it was necessary to perform combined myocardial and renal revascularization rather than staged procedures. At the time of coronary artery bypass grafting, a vein graft was anastomosed to the right coronary artery vein graft and tunneled through the diaphragm into the abdomen to revascularize both renal arteries. After surgery renal function gradually improved, and no further dialysis was required. The abdominal aortic aneurysm was repaired at a subsequent operation. At 2-year follow-up all grafts remained patent. The serum creatinine is 1.2 mg/dl. Although most patients with combined coronary artery disease and renal artery disease can be treated with staged operations, our procedure may be of value in patients in whom staged procedure are not feasible and in whom the infrarenal aorta is severely diseased or aneurysmal.
 ...
PMID:Combined coronary artery bypass grafting and bilateral renal revascularization for unstable angina and impeding renal failure. 199 71

Renal effects of 1,4-dihydropyridine (DHP)-type calcium antagonists (nitrendipine and nisoldipine) were analyzed in diverse conditions, such as long-term antihypertensive treatment, acute saline-loading, and acute renal failure in rats. In spontaneously hypertensive rats (SHR), 60-week treatment with nitrendipine resulted in normotensive blood pressure values without increasing body weight, an indicator of salt-water retention, or increasing plasma renin activity and plasma aldosterone concentration compared with the untreated rats. After acute saline-loading of normotensive or hypertensive rats, administration of calcium antagonists nitrendipine and nisoldipine increased urinary volume and sodium excretion. This was in contrast to the effects observed with the vasodilator minoxidil, with which salt-water retention was shown. In acute renal failure induced by 60-min renal ischemia in uninephrectomized rats, administration of nisoldipine decreased mortality rate and improved kidney function. The increase in renal tissue calcium content and the decrease in ATP content associated with the renal failure was abolished by nisoldipine treatment. In conclusion, renal protective effects are present with DHP-type calcium antagonists; however, mechanisms in situations such as hypertension or acute renal failure might be different and deserve further analysis.
 ...
PMID:Renal effects of 1,4-dihydropyridines in animal models of hypertension and renal failure. 244 Nov 91

The effect of ketanserin (Kt) has been analyzed during the development of two-kidney-two-clip (2k-2c) renovascular hypertension in the rat. Male Wistar rats were divided into four experimental groups: (1) clip Kt (ClKt) (n = 12)--A silver clip (0.25 mm width) was placed in each renal artery 3 days after beginning the administration of Kt (10 mg/kg/day) in the drinking water; (2) sham Kt (ShKt) (n = 13)--Similar to group 1, but the clips were placed in, and immediately removed from, the renal arteries; (3) untreated clip (UCl) (n = 10)--Similar to group 1, but the rats drank water; (4) untreated sham (USh) (n = 10)--Similar to group 2, but the rats drank water. Blood pressure (BP) was measured before surgery and was followed weekly for 7 weeks. At the end of this period, blood and cerebrospinal fluid (CSF) samples were obtained in all the animals. Plasma renin activity (PRA) and plasma and CSF angiotensinogen concentration (AoC) were evaluated. The results have shown that Kt partially inhibited the increase in BP induced by bilateral renal ischemia (BP: UCl rats 180.5 +/- 12.4 versus ClKt rats 149.8 +/- 5.1 mm Hg; p less than 0.01; USh rats 116.7 +/- 3.7; ShKt rats 114.4 +/- 5.0 mm Hg). PRA was similar in hypertensive and control rats whether or not they had received Kt. AoC in plasma was decreased in clipped treated and untreated rats.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Chronic administration of ketanserin and the development of two-kidney-two-clip Goldblatt renovascular hypertension in the rat. 244 74

The effect of atrial natriuretic polypeptide (ANP) on hemodynamics and renal function was evaluated after the reconstructive surgery of the left renal artery in a patient with renovascular hypertension secondary to Takayasu's arteritis. The reconstructive surgery was done using the femoral artery, since we were unable to obtain adequate vein segments to fit the renal artery. The femoral artery was reconstructed by her saphenous vein segments. After 30 min of the aortorenal bypass operation, alpha-human ANP (alpha-hANP) was infused intravenously for 10 min at a rate of 0.1 microgram/kg/min. Although total peripheral resistance was decreased by alpha-hANP infusion, blood pressure was not changed because of the increased cardiac output. Glomerular filtration rate was increased markedly with concomitant increase in urine volume and urinary excretions of sodium, potassium and phosphate. Fractional excretions of water and sodium were not changed, but fractional excretion of phosphate and potassium clearance were increased. Thus, the infusion of alpha-hANP markedly improved the renal function of the ischemic kidney by the reconstructive surgery of the renal artery, suggesting that alpha-hANP seems clinically applicable as a protective agent in renal ischemia at renovascular surgery as well as the renal transplantation.
 ...
PMID:Atrial natriuretic polypeptide (ANP) as protective agent of renal ischemia. 253 78

The renovascular hypertension in the Wistar rats was induced by clipping both renal arteries. Within 3-4 weeks arterial pressure (AP) increased to maximal values. According to AP, the rats were divided into two groups: with AP less than or equal to 170 mm Hg and greater than 170 mm Hg. In 5-6 or 10-11 weeks the animals were decapitated and the Na,K-ATPase activities in the wholesome erythrocytes, their ghosts, and the cortex and medulla of kidneys were studied. Changes of the enzyme activity were only found in the medulla. A decreased enzyme activity (-20%) was revealed in the rats with AP less than or equal to 170 mm Hg within 5-6 weeks after renal ischemia, the activity increasing again in 10-11 weeks after the operation. The decreasing of Na,K-ATPase activity within 5-6 weeks after renal ischemia could be a mechanism of adaptation of the salt-water balance in animals.
 ...
PMID:[Effect of bilateral renal ischemia on the sodium, potassium ATPase activity of the kidneys and erythrocytes in rats]. 254 69

In a 22 years old woman with recent hypertension, a timed intravenous pyelogram revealed an asymptomatic obstructive ureteropelvic junction. Preoperative renal vein catheterization demonstrated excessive renin release from the diseased kidney and low release from the other one, suggesting that corrective ureteral surgery should return blood pressure to normal levels. Moderately impaired glomerular filtration rate improved after surgery as a consequence of suppressed hydronephrosis and bilateral renal ischemia. Thus we conclude that in young people, asymptomatic unilateral hydronephrosis can lead to hypertension and renal failure like renal artery stenosis. In the other cases of urinary flow obstruction, secondary hypertension remains to be explained by both inappropriate production of renin and water chronic retention.
 ...
PMID:[Arterial hypertension with renin hypersecretion secondary to pyelo-ureteral syndrome. Cure after corrective surgery]. 269 10


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>