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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vasodilator substances act either directly on vascular smooth muscle (e.g., adenosine) or indirectly (e.g., acetylcholine) on endothelial cells that respond by releasing an unknown powerful, short-lived relaxing factor. To determine whether chronic hypertension or hypercholesterolemia or both would alter the release of the endothelium-derived relaxing factor, experiments were performed in hypertensive rabbits (5-week cellophane wrap perinephritis; mean blood pressure, 134.7 mm Hg) and normotensive rabbits (mean blood pressure, 80 mm Hg) with a Doppler flow transducer and perivascular balloon implanted on the lower abdominal aorta. Rabbits were fed either 1% cholesterol or control diet for 4 weeks before the experiment. On the day of the experiment, resting hindlimb vascular resistance was greatest in hypertensive rabbits fed 1% cholesterol diet, followed (in descending order) by hypertensive rabbits, normotensive rabbits fed 1% cholesterol diet, and normotensive rabbits. Pharmacological autonomic reflex blockade was induced, and steady state intravenous infusion curves to acetylcholine, serotonin, and adenosine were constructed. Sensitivity (location of effective dose, 50%) to the three vasodilator agents was altered less than twofold from the values in normotensive rabbits for any treatment group. The maximum vasodilator response to acetylcholine, but not to adenosine or serotonin, infusion was reduced significantly in the treated rabbits compared with that in normal rabbits. Reactive hyperemic responses to 5 to 80 seconds of ischemia were not significantly different among the treatment groups. These results indicate that hypertension with or without hypercholesterolemia does not greatly alter the responsiveness of the hindlimb resistance vasculature to these three vasodilator agents or to ischemia.
Hypertension 1986 May
PMID:Effects of hypertension and hypercholesterolemia on vasodilatation in the rabbit. 369 79

The counter-regulatory effects in response to blood pressure reduction by propyldazine were studied in conscious dogs with bilateral cellophane perinephritis hypertension. During a 22-day period of chronic treatment, the initial increase in heart rate, plasma renin activity, angiotensin II, aldosterone, and vasopressin, which indicate counter-regulation to the drug induced decrease in blood pressure, vanished. On the fifth day of treatment another, presumably cellular mechanism, had taken over the restitution of blood pressure and thereby led to tolerance towards the action of further propyldazine administration. Seven days after the end of chronic treatment a renewed propyldazine administration did not produce the same effects as obtained with the first administration; after 28 days the hypotensive effect of propyldazine was identical to the one observed before treatment.
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PMID:Effects of long-term administration of propyldazine on blood pressure and counter-regulatory systems in conscious hypertensive dogs. 382 11

We examined the relationship of hypertension and plasma renin activity to atherogenesis in 48 moderately hyperlipidemic (total serum cholesterol was about 200 mg/dl) baboons (Papio sp.). We used renal artery stenosis (two-kidney, one clip model) to produce hypertension associated with elevated plasma renin activity, and used cellophane wrapping of both kidneys (bilateral perinephritis model) to produce hypertension with normal renin activity. Renal artery stenosis and bilateral perinephritis increased both systolic and diastolic blood pressure by about 30 mm Hg. Renal artery stenosis approximately doubled, but bilateral perinephritis did not change plasma renin activity. Both hypertensive groups, to about the same degree, had significantly more extensive atherosclerosis than the control group in the abdominal aorta and brachial, iliac-femoral, and carotid arteries. The effect of hypertension was greatest in the carotid arteries where the extent of atherosclerosis was nearly tripled. Hypertension did not influence lesions in the thoracic aorta. By multiple regression analysis, very low plus low density lipoprotein cholesterol, high density lipoprotein cholesterol, and systolic blood pressure were consistently strong predictive variables for the extent of atherosclerotic lesions. Most of the effects of renal hypertension on atherosclerotic lesions appeared to be accounted for by the increase in blood pressure. In the carotid arteries, however, there was a suggestion of an effect above that due to increased blood pressure. Additional analyses indicated that these treatment effects were associated with serum potassium concentration, plasma renin activity, or other closely related variables.
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PMID:Effects of two forms of hypertension on atherosclerosis in the hyperlipidemic baboon. 389 70

The radioactive microsphere technique was used to study the systemic and regional haemodynamic effects of the converting enzyme inhibitor captopril (0.1, 0.3 and 1.0 mg/kg) 10 min after intravenous administration in conscious rabbits with bilateral cellophane perinephritis hypertension, an experimental model of hypertension associated with normal plasma renin levels. Captopril lowered arterial blood pressure as a result of a dose-dependent decrease in total peripheral resistance. The fall in blood pressure was accompanied by an increase in cardiac output after the second and third dose of captopril; heart rate was not significantly altered. Captopril produced a generalized peripheral vasodilatation; the changes in vascular conductance being most pronounced in the kidneys, intestines and skin which resulted in a significant increase in blood flow to these vascular beds. The effective antihypertensive properties of captopril in this 'low plasma renin' model of hypertension and the uniform increase in vascular conductances produced by captopril, which antagonizes the generalized increase in vascular resistances that characterizes cellophane perinephritis hypertension, may indicate the involvement of an increased activity of the renin-angiotensin system, possibly in tissues, such as the vascular wall and brain, in the maintenance of the elevated blood pressure in this hypertensive form.
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PMID:Systemic and regional haemodynamic profile of captopril in conscious rabbits with bilateral cellophane perinephritis hypertension. 391 85

2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-difluoromethoxy-p hen yl)-1,4-dihydropyridine (ryodipine, PP-1466) causes lasting decrease in systolic and diastolic arterial pressure at intravenous and oral administration to anesthetized animals. In conscious rats with DOCA-salt (des-oxycortone) and spontaneous hypertension, as well as in rats with hypertension provoked by method of cellophane perinephritis, PP-1466 (1 and 10 mg/kg, orally) decreases systolic pressure considerably. Therapeutic doses of PP-1466 do not essentially affect rhythm and frequency of cardiac contractions. High doses of the drug increase the heart rate. PP-1466 increases coronary blood flow. PP-1466 antagonizes considerably the pressor effect of angiotensin. In this respect PP-1466 is superior to SKF-24260 (2,6-dimethyl-3,5-diethoxycarbonyl-4-(o-difluoromethylphenyl)-1, 4-dihydropyridine). PP-1466 reduces hypotensive reaction and tachycardia induced by isoprenaline administration, inhibits decrease in arterial pressure caused by electric stimulation of the vagus nerve and administration of acetylcholine. Hypotension caused by PP-1466 and its negative inotropic effect can be antagonized with calcium chloride. In mice and rats PP-1466 at doses exceeding 10 mg/kg exerts a certain dose dependent depressant effect on the CNS. More protracted depressant effect on the CNS is exerted by nifedipine which was studied parallelly. In rabbits oral PP-1466 decreases in EEG basic rhythm amplitude both in cortical and subcortical structures. High doses of the drug lead to dysrhythmia in bioelectric activity. Acute, subacute and chronic toxicity studies in mice, rats and dogs show that PP-1466 possesses low acute toxicity and is well tolerated at protracted repeated administration of therapeutic and several times higher doses.
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PMID:Pharmacological and toxicological properties of ryodipine. 401 33

In rat smooth muscle cell cultures two types of cells were detected. The majority of cells were small and spindle-shaped, 15% of which were labeled with H3-thymidine and displayed a nucleus/plasma relation of 1:15. Thirteen percent of the smooth muscle cell population was large and partly polynuclear. The H3-thymidine labeling was 1.3% in these rounder cells, and the nucleus/plasma ratio was 1:44. The surface area and cell shape of both types of cells were quantified morphometrically. Diabetes was induced in a group of animals by streptozotocin and hypertension by cellophane perinephritis. Data on smooth muscle cells (SMC) in culture obtained from diabetic and hypertensive rats differed from those of the controls. The percentage of small cells was significantly decreased, while the H3-thymidine index was increased in both diabetic and hypertensive rats. The number of large and polynuclear cells increased relative to the small cells, and they also displayed a higher proliferation rate as well as a change in their nucleus/plasma ratio. Another group of diabetic animals was treated with acetylsalicylic acid prior to SMC cultivation. Acetylsalicylic acid prevented the majority of changes found in cultured SMC of diabetic rats.
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PMID:Special characteristics of cultured smooth muscle cell subtypes of hypertensive and diabetic rats. 622 11

Bromolasalocid (Ro 20-0006) is a calcium ionophore with antihypertensive activity that does not belong to any known class of antihypertensive agents. Bromolasalocid produces a relatively flat systolic blood pressure dose-response effect in the spontaneously hypertensive rat. An intensive cardiovascular evaluation of bromolasalocid at the highest dose used in the dose-response study showed full hemodynamic compensation; there was a significant decrease in both mean arterial blood pressure and peripheral resistance without a significant decrease in cardiac index. The antihypertensive action of bromolasalocid lasts many days after termination of dosing. Bromolasalocid is specifically antihypertensive and does not decrease arterial blood pressure in normotensive animals or in animal models of hypertensive cardiovascular disease with normal pulse pressures. Bromolasalocid is not a vasodilator and appears to mediate its antihypertensive action by restoring compliance of the large conduit arteries. Both the derived arterial compliance index and the blood pressure-pressor response to the carotid occlusion reflex are enhanced in the dog perinephritis model of hypertensive cardiovascular disease treated with bromolasalocid. Bromolasalocid appears to reverse the damage to cardiovascular tissue caused by prolonged hypertension via an action on calcium perturbations in large artery smooth muscle cells.
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PMID:Bromolasalocid (Ro 20-0006) antihypertensive ionophore. 682 90

Using the radioactive microsphere technique, systemic and regional hemodynamic variables were measured in normotensive rabbits and in rabbits with bilateral cellophane perinephritis hypertension. An average decrease in cardiac output of 18 percent was measured in the hypertensive rabbits as a result of a reduction in stroke volume; heart rate remained unchanged. Thus, in the established phase, hypertension was maintained by the elevated total peripheral resistance. A redistribution of cardiac output was observed in the hypertensive rabbits; a significantly higher fraction was received by the brain, small intestine and heart. The weight normalized blood flow to the kidneys, spleen, skeletal muscles, bones and fat was significantly decreased while an increase in vascular resistance was observed in the hypertensive rabbits in all the organs investigated. A negative correlation existed between the weight of the left ventricle and the blood flow to the left ventricle in hypertensive rabbits, suggesting inadequate coronary perfusion as myocardial hypertrophy becomes more pronounced.
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PMID:Systemic and regional hemodynamic characteristics of bilateral cellophane perinephritis hypertension in conscious rabbits. 688 48

The authors report the results from the follow-up of 14 patients with transplanted kidney, three out of them with a lethal end--mycotic sepsis--1, purulent peritonitis--1 and of transplant lung-syndrome--1. The rest (11-78,5%) were in a good condition during 1 year and 8 months to 6,5 years (an average of 4 years and 10 days by April 30, 1980). Eleven of the patients had their transplantations performed by Prof. Sumakov--Prof. Levizkii in Moscow and three--by Prof. Hamburger, Prof. Crosnier, Prof. Lacomb in Necker Hospital, Paris. During the follow-up period those 14 patients had the following complications: 15 acute crises of rejection, successfully coped, with residual phenomena in 4 of them; 10--uroinfections, 7--other infections, one mycotic sepsis and one purulent peritonitis with a lethal end; three with epidermic hepatitis, one--Herpes zoster, two bronchopneumonias, one perinephritis, 6--with arterial hypertension that necessitated binephrectomy in two, three patients with steroid diabetes--cured, four with aseptic osteonecrosis of the head of the femur, necessitating prosthesis of the femoral joint in one patient, 5--with surgical complications, corrected at the transplantation centers. Furthermore, one case with transplant lung-syndrome, successfully restored to health as reported by the authors. All those 11 patients with transplantations are in good health (one with a chronic rejection crisis) and 8 of them--work. The authors stress upon the follow-up of the renal patients with transplantation as an important step, consolidating the remote results of renal transplantation.
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PMID:[Our experience with the dispensary observation and treatment of kidney transplant patients]. 701 86

The authors report a case of lithiasis of the renal pelvis which had progressed for several years and was complicated by severe perinephritis and peripyelitis. This inflammatory reaction around the kidney affected the renal pedicle and caused constriction of the renal artery. This arterial obstruction resulted in hypertension and such a reduction in the blood supply to the kidney that nephrectomy was performed without any haemostasis of the pedicle. This case is reported because of its rarity.
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PMID:[Nephrectomy without hemostasis of the pedicle]. 717 17


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