Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fourteen patients with mild to moderate essential hypertension were randomized, after a baseline placebo period of 4 weeks, to receive the angiotensin converting enzyme (ACE) inhibitor quinapril or a placebo. During a 12 week, double-blind phase, the dosage of quinapril was increased from 10 to 40 mg twice daily being doubled every 4 weeks. At the end of the baseline period and of each month of the double-blind phase, 12 h overnight urine collections were made and morning blood samples were taken about 12 h after the last dose of medication. During the double-blind phase, blood pressure in the quinapril group (n = 7) decreased from 159 +/- 3/105 +/- 1 to 141 +/- 6/94 +/- 2 mm Hg (mean +/- SEM). Serum ACE activity and plasma angiotensin II concentration were reduced to 4 +/- 1% and 14 +/- 1% of the pretreatment values, respectively. Neither the plasma concentrations nor the urinary excretions of prostaglandin E2, 6-keto-prostaglandin F1 alpha (a prostacyclin metabolite), or thromboxane B2 (a metabolite of thromboxane A2) were affected by quinapril. In the placebo group, blood pressure tended to decline but the biochemical variables remained essentially unchanged. These results indicate that prostanoids are not involved in the antihypertensive action of quinapril, the principal effect of which seems to be inhibition of the renin-angiotensin system.
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PMID:Effects of the converting enzyme inhibitor quinapril (CI-906) on blood pressure, renin-angiotensin system, and prostanoids in essential hypertension. 245 40

In essential hypertension, ventricular function is determined primarily by the degree of hypertrophy (myocardial factor) and by the organic complications in the coronary artery (coronary factor). Ventricular function is inversely correlated with ventricular size and systolic wall stress, inasmuch as ventricular function diminishes when these two variables increase. Coronary reserve is reduced even in hypertensive hypertrophy without evidence of coronary artery disease. MVO2 per mass unit is directly correlated with systolic wall stress per cross-sectional area of the left ventricular wall. It is concluded that the appropriateness of left ventricular hypertrophy, as a result of mass-to-volume ratio and stress, is a major determinant of left ventricular performance, of coronary blood flow, and of myocardial oxygen consumption. Pharmacotherapeutical means of reversing cardiac hypertrophy (prazosin, clonidine, enalapril, and nifedipine) were analyzed in concentrically, as well as eccentrically, hypertrophied left ventricles. Regression of cardiac hypertrophy, i.e., therapeutic intervention on a critical precursor of hypertensive congestive heart failure, can be obtained by various antihypertensive agents. Prazosin, calcium channel blockers, and angiotensin converting enzyme inhibitors as well as a combined treatment regimen using alpha-receptor blockers together with diuretics and vasodilators can all induce regression of hypertrophy associated with an improvement in left ventricular function. Moreover, an improved coronary reserve may reduce the ischemic risk of the hypertrophied myocardium. However, not all antihypertensive drugs seem equally effective in bringing about coronary regression of left ventricular hypertrophy (LVH). No regression or little regression has been found with diuretic monotherapy despite a satisfactory reduction in blood pressure. On the other hand, a trend towards a regression has been observed in patients in whom treatment with clonidine significantly reduced catecholamines. Recent experimental data in spontaneously hypertensive rats indicate that the impaired coronary reserve can be significantly improved by the long-term administration of blood pressure lowering agents, e.g., by nifedipine or by the combination of metoprolol plus hydralazine.
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PMID:Regression of myocardial and coronary vascular hypertrophy in hypertensive heart disease. 246 73

Three hundred thirty-one patients with mild to moderate essential hypertension, 182 males and 149 females with a mean age of 54 (range, 17-87 years), were studied for 1 year in a clinical trial with ramipril, an angiotensin converting enzyme (ACE) inhibitor. The patients included had completed double-blind trials with ramipril vs. captopril, HCT, atenolol and ramipril plus piretanide. All cases were treated first with 5 mg ramipril and, where appropriate, also with 25 mg HCT. Adjustment of the dose in the range 1.25-20 mg ramipril was left to the investigator. Overall, a consistent reduction in blood pressure was achieved. Only small changes in mean blood pressure were noted during the 12 months (mean diastolic blood pressure 84.3-86.9 mm Hg, mean systolic blood pressure 145.6-148.2 mm Hg). Two hundred sixty-two (82%) of the 331 patients had diastolic values consistently equal to or lower than 95 mm Hg. There was a downward shift in the dosages upon which the investigators finally settled during the 12-month period in the patients receiving ramipril monotherapy. In patients also receiving HCT the initial dose was increased in most cases. Adverse events were observed in 6.7% of patients taking ramipril alone. The most frequent symptoms were dizziness, asthenia, pain in the upper abdomen and headache. Adverse effects occurred more frequently under continuous additional treatment with HCT, the same symptoms being reported. The clinical trial was prematurely terminated in six patients, in only two cases for medical reasons. The analysis of the laboratory findings revealed no general deterioration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An open multicenter study to assess the long-term efficacy, tolerance, and safety of the oral angiotensin converting enzyme inhibitor ramipril in patients with mild to moderate essential hypertension. 247 9

The renin-angiotensin system has a wide range of physiological actions, and thus interference with the system has attractive therapeutic potential. The orally active angiotensin converting enzyme (ACE) inhibitors have so far been the most successful drugs in this area. They lower arterial pressure both in renovascular and essential hypertension, and their effects are enhanced by concomitant diuretic therapy or dietary salt restriction. Since, in renovascular hypertension, the affected kidney depends on enhanced local generation of angiotensin II to help preserve its function, the circulation and excretory capacity of this kidney may be compromised with ACE inhibition. ACE inhibitors can improve exercise tolerance and diminish cardiac ventricular arrhythmias in patients with heart failure. Because these drugs lower plasma aldosterone, they tend to correct potassium deficiency and hypokalemia, which may have been induced by diuretic treatment. Hypotension can occur with the first dose of ACE inhibitor, especially in sodium-depleted subjects; in patients on prior antihypertensive therapy, particularly if this includes a diuretic; and in the elderly. Not all of the actions of ACE inhibitors are necessarily due to lowering of plasma angiotensin II: accumulation of kinins may be responsible for some of the effects and side effects. Common to all ACE inhibitors are occasional rashes, cough, and, more rarely, angioedema. Apparently peculiar to captopril, and less often seen with the lower doses now employed, are taste disturbance, proteinuria, and marrow depression. ACE inhibitors, should not be used in pregnant women.
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PMID:Converting enzyme inhibitors in the treatment of hypertension. 248 62

Glomerular filtration rate (GFR) and tubular function were measured by means of the lithium clearance technique in 14 patients with renovascular hypertension (RVH) and eight patients with essential hypertension (EH) before and after oral administration of captopril 25 mg. In RVH captopril reduced 51-Cr-EDTA clearance (67.3 (median) to 47.5 ml min-1, P less than 0.01), proximal absolute reabsorption of fluid (53.9 to 41.5 ml min-1, P less than 0.01) and distal absolute reabsorption of sodium (2195 to 1402 mumol min-1, P less than 0.01), whereas proximal fractional reabsorption increased slightly (77.5 to 80.2%, P less than 0.02). In EH, however, these parameters were practically unaffected by captopril. In both RVH and EH plasma concentrations of angiotensin II and aldosterone were reduced after captopril, but atrial natriuretic peptide in plasma and urinary excretion rate of prostaglandin E2 were unchanged. Blood pressure decreased after captopril in both groups, but the maximum fall in systolic BP was more pronounced in RVH (22%) than EH (13%). It is concluded that angiotensin converting enzyme inhibition markedly reduced absolute reabsorption in both the proximal and distal tubules in RVH, in contrast to EH, predominantly due to fall in the GFR, and that the slight increase in proximal fractional reabsorption may be attributed to a reduction in the hydrostatic pressure in the peritubular vessels.
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PMID:Abnormal glomerular and tubular function during angiotensin converting enzyme inhibition in renovascular hypertension evaluated by the lithium clearance method. 249 71

The main vasodepressor hormone systems are the kallikrein-kinin systems and the vascular prostacyclin. Kallikreins release kinins which are the biological active compounds of the kallikrein-kinin systems. Kinins are one of the most potent vasodilators reducing systemic blood pressure by diminution of vascular resistance. The reduction in blood pressure is strongly dose related. Prostacyclin develops similar effects on blood pressure as kinins. There is a close relationship between kinins and prostacyclin since kinins stimulate prostacyclin synthesis very effectively. In arterial hypertension there is a lack in kallikrein-kinin and prostacyclin activity. This could also be shown under experimental conditions in spontaneously hypertensive and in Dahl salt-sensitive rats. In clinical studies these experimental results were confirmed in primary hypertension. The blood pressure response to exogenous vasodepressor hormones is increased in hypertensives suffering from reduced endogenous vasodilator activity. In the knowledge of reduced vasodilator activities in primary hypertension the stimulation of kinins by prostacyclin will be of major interest in the management of primary hypertension. In the last years some drugs have been investigated with regard to their kinin prostacyclin stimulating effect, but only angiotensin converting enzyme inhibitors, linolenic acid and cicletanin seemed to induce therapeutic prostacyclin stimulation. However, it remains unclear whether these drugs develop their blood pressure lowering effect by stimulation of the discussed vasodilators or by some other effect.
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PMID:Role of kinins and prostacyclin in blood pressure regulation. 251 56

1. The pharmacokinetics of a single 1 mg dose of cilazapril were determined in six subjects with normal renal function and in 19 uraemic patients with various degrees of renal impairment. 2. Significant decreases in systolic and diastolic blood pressure were noted in all groups of subjects between 2 and 8 h after administration of 1 mg cilazapril. 3. There was a significant correlation between ACE inhibition at 24 h and creatinine clearance (CrCL). 4. For cilazapril, Cmax and tmax were independent of creatinine clearance. AUC(24) was inversely related to CrCL and apparent plasma clearance (CL/F) was directly related to CrCL. 5. For cilazaprilat, Cmax and tmax were related to creatinine clearance. AUC(24) was inversely related to CrCl and apparent plasma clearance (CL/F) was directly related to CrCL. 6. Dialysis clearance was approximately 2 l h-1 for cilazapril and for cilazaprilat. 7. The effects of renal impairment on cilazapril and cilazaprilat kinetics were similar to those observed for other inhibitors of angiotensin-converting enzyme such as captopril, enalapril and lisinopril. 8. It may be necessary to modify doses of cilazapril for the treatment of essential hypertension in uraemic patients. When creatinine clearance was below 15 ml min-1 cilazaprilat concentrations were increased, half-lives were prolonged and ACE inhibition remained above 90% for at least 24 h. A reduced dosage is indicated for these patients. 9. In patients requiring haemodialysis, maintenance doses of 0.5 mg given after each haemodialysis session are sufficient.
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PMID:Pharmacokinetics of cilazapril in patients with renal failure. 252 39

Left ventricular hypertrophy (LVH) is a common sequela of long-standing essential hypertension. LVH cannot be considered, however, an adaptive process only serving to normalize wall stress but can be considered one that significantly increases the risk of sudden death, myocardial ischemia, congestive heart failure, and other cardiovascular diseases. Patients with LVH exhibit impaired ventricular filling, ventricular arrhythmias, and myocardial ischemia even in the absence of coronary artery disease. LVH can be prevented or reversed by a variety of antihypertensive agents including calcium channel blockers and angiotensin converting enzyme inhibitors. Calcium channel blockers, more than angiotensin converting enzyme (ACE) inhibitors, suppress ectopic impulse generation, improve ventricular compliance, and alleviate myocardial ischemia while preserving or improving the contractile state. In contrast, ACE inhibitors can be particularly useful in patients with LVH and diminished ventricular contractility and in preventing chamber dilatation after myocardial infarct. These favorable cardiovascular effects of both calcium channel blockers and ACE inhibitors are a reason for optimism that carefully tailored therapy will ultimately diminish the well-documented risk of cardiovascular morbidity and mortality associated with LVH.
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PMID:Effects of antihypertensive therapy on hypertensive heart disease. 253 79

In seven patients with mild to moderate essential hypertension, the effect of a new angiotensin converting enzyme (ACE) inhibitor, cilazapril, on atrial natriuretic factor (ANF) was examined at rest and during exercise. The exercise protocol consisted of three fixed workloads (25, 50 and 75W) every 4 min with the use of a sitting bicycle ergometer. Cilazapril reduced blood pressure without increasing the heart rate, both at rest and during exercise. The resting pre-exercise left ventricular ejection fraction was not altered. The plasma ANF level was increased by exercise, but at the 75-W workload it was decreased by cilazapril; the resting plasma ANF value was not altered. At the 75-W workload the plasma ANF level was inversely correlated to the left ventricular ejection fraction (n = 14, r = -0.64, P less than 0.01). These results suggest that the observed decrease in the plasma ANF level during exercise induced by cilazapril is, in part, related to an improvement in the cardiac overload, and that cilazapril may be effective in physically active hypertensive patients.
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PMID:Effect of a new angiotensin converting enzyme inhibitor, cilazapril, on circulating atrial natriuretic factor during exercise in patients with essential hypertension. 253 17

After a 2-4 week no-treatment period, 24 patients (12 young, age 29-45 yr.; 12 elderly, age 65-81 yr.; 20 black, 4 white) with an untreated sitting diastolic blood pressure between 91-120 mm Hg received the nonsulfhydryl angiotensin converting enzyme inhibitor, lisinopril for three weeks in a singleblind, parallel group comparison. Patients who did not achieve goal blood pressure with the initial low-dose (10 mg/day) were treated with a high-dose regimen (40 mg/day) for three weeks. In those who remained incompletely responsive, hydrochlorothiazide 25 mg/day was added for four weeks in an attempt to normalize blood pressure (less than or equal to 90 mm Hg). Low-dose lisinopril monotherapy produced comparable reductions in the mean systolic and diastolic blood pressures (approximately -15/-8 mm Hg in both younger and older patients). Increasing the dose produced a slightly greater fall in mean blood pressures which normalized the blood pressure in five of six elderly patients unresponsive to the lower dose; addition of hydrochlorothiazide normalized three of the five remaining subjects from both groups who were unresponsive to high dose lisinopril. Lisinopril administration resulted in a rise in plasma renin activity and a fall in plasma aldosterone concentrations which were similar in both groups and which returned over time toward the baseline. The drug was well tolerated, producing one episode of symptomatic hypotension following the addition of hydrochlorothiazide to lisinopril monotherapy. Lisinopril alone or in combination with hydrochlorothiazide produces favorable antihypertensive effects in both younger and older predominantly black, low-renin patients with essential hypertension.
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PMID:The antihypertensive response to lisinopril: the effect of age in a predominantly black population. 254 Feb 24


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