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Biomedical subjects

A Salvetti

Publications and source records attributed to A Salvetti.

At least 217 records · Page 12Linked to original sources
PubMed1986

Acute response to captopril as a predictive test for surgery in renovascular hypertension.

To test the hypothesis that acute angiotensin-converting enzyme (ACE) inhibition might predict the postoperative blood pressure outcome, a single oral dose of captopril ranging from 12.5 to 100 mg, was given to 26 patients with renovascular disease and its hypotensive effect was compared with that of surgery (21 patients) or of percutaneous transluminal angioplasty (PTA) (5 patients). Both systolic and diastolic blood pressure fell significantly (p less than 0.001) from 179.9 +/- 5.4/114.1 +/- 2.1 to 148.4 +/- 3.8/94.1 +/- 1.9 after captopril and to 141.1 +/- 3.7/88.9 +/- 2.0 at least 3 months after operation. Postoperative pressure values were directly related to those after captopril (SBP: r = 0.65, p less than 0.001; DBP: r = 0.45, p less than 0.05) as were their absolute decrements (SBP: r = 0.70, p less than 0.001; DBP: r = 0.64, p less than 0.001). However, after captopril, individual pressure tended to be higher (and their decrements to be lower) than after operation. 12 out of 19 patients cured by surgery were considered cured by captopril, while 5 out of the remaining 7 were improved and 2 not cured. The 6 patients improved by surgery or PTA were also improved by captopril and the only patient not cured by surgery was not cured by captopril. Therefore, if we consider both cure and improvement as a positive result, the captopril test gave 23 true-positive, 1 true-negative and 2 false-negative responses. Taken together, these data suggest that acute ACE inhibition may be an useful tool in predicting postoperative blood pressure of patients with renovascular disease.

Adolescent↗
PubMed1986

Vascular responses to ouabain and norepinephrine in low and normal renin hypertension.

A circulating Na+, K+-ATPase inhibitor may cause arterial hypertension in patients with suppressed plasma renin activity, either directly or by sensitizing peripheral vessels to alpha-adrenergic stimulation. This hypothesis was tested by evaluating forearm arteriolar (plethysmographic technique) response to exogenous alpha-adrenergic stimulation by a 2-minute intra-arterial infusion of norepinephrine (0.1 microgram/dl tissue per minute) and to Na+, K+-ATPase inhibition by sequential 20-minute intra-arterial infusions of ouabain (0.36 and 0.72 microgram/dl tissue per minute). Two groups of hypertensive subjects with suppressed plasma renin activity, either essential or secondary to aldosterone excess, were compared with age-matched and sex-matched hypertensive subjects with normal plasma renin activity (n = 7 per group). No significant differences in forearm vascular response to norepinephrine were found among the three groups. Ouabain caused a highly significant, dose-related increment in forearm vascular resistance that was not accompanied by changes in the contralateral limb or systemic blood pressure. No significant interindividual differences in vascular responsiveness to ouabain were found. The individual increments in forearm vascular resistance during ouabain administration were unrelated to basal values or to plasma aldosterone, norepinephrine, or potassium concentrations. These data are not consistent with the hypothesis that suppressed basal Na+, K+-ATPase activity is primarily a characteristic of hypertensive patients with unresponsive plasma renin activity. Overall, these results cast doubts on the possibility of linking the development of human low renin hypertension to an endogenous Na+, K+-ATPase inhibitor.

Adult↗
PubMed1986

Verapamil antagonizes forearm vasoconstriction mediated by selective alpha 1- and alpha 2-agonists in hypertensive patients.

Calcium channel blocking agents preferentially antagonize alpha 2-mediated pressor responses in various animal species. Whether the same happens in man is not clear. For this reason we studied the interference exerted by verapamil, a calcium entry blocker, on forearm vasoconstriction mediated by selective alpha 1- (methoxamine) and alpha 2- (B-HT 933) adrenergic agonists in untreated mild-to-moderately hypertensive patients (n = 22). Each patient underwent a single study. Forearm blood flow was recorded by strain gauge venous plethysmography; all drugs were infused into the brachial artery at systemically ineffective rates. Cumulative dose-response curves to intra-arterial methoxamine or B-HT 933 were obtained during saline or two different rates of verapamil infusion (0.9 and 3.1 micrograms/100 ml forearm tissue per min) which increased forearm blood flow dose-dependently without changing systemic blood pressure or heart rate. Either methoxamine or B-HT 933 decreased forearm blood flow during saline infusion, but their effect was blunted in a dose-dependent manner during verapamil. No evidence of preferential alpha 2-antagonism was present. At variance with animal data, calcium entry blockade by verapamil antagonizes either alpha 1- or alpha 2-mediated vasoconstriction in human forearm vessels.

Adrenergic alpha-Agonists↗
PubMed1986

Potassium-rich and sodium-poor salt reduces blood pressure in hospitalized patients.

To investigate whether a K-rich/Na-poor salt is able to reduce blood pressure, 10 mildly hypertensive inpatients (six males) aged 28-53 years, with supine diastolic blood pressure (DBP) greater than 95 mmHg after 5 days of hospitalization, on a standard diet containing about 20 mmol Na plus 4 g common salt (CS) were randomly given, in double-blind conditions, 2 g twice daily of either CS (five patients) or K-rich/Na-poor salt (five patients) to add to food for a further 8 days. Mean blood pressure was significantly (P less than 0.01) reduced to a similar extent in both groups in the first 4 days, and declined significantly (P less than 0.01) only in the K/Na group in the following 8 days, reaching values significantly (P less than 0.01) lower than those of the CS group. The heart rate did not change significantly while body weight decreased to a similar extent in both groups. Urinary sodium excretion was similarly and significantly (P less than 0.01) reduced in both groups in the first 4 days (CS 100.8 +/- 7.9 and K/Na 100.2 +/- 11.0 mmol/24 h, and remained unchanged in the CS group (109.9 +/- 4.3 mmol/24 h) but declined significantly (P less than 0.05) by about 50% in the K/Na group (62.9 +/- 3.6 mmol/24 h) in the following 8 days. Plasma renin activity (PRA) and plasma noradrenaline did not differ significantly between the two groups, nor among the days of treatment, but the mean blood pressure response to mental stress was reduced significantly (P less than 0.4) in the Na/K group compared with the CS group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Multicentre comparison of the antihypertensive effect of acebutolol and hydrochlorothiazide in uncomplicated mild-moderate hypertension in the elderly.

To evaluate the efficacy of acebutolol, 400-600 mg/day in elderly hypertensive patients, and to compare it with hydrochlorothiazide 25-50 mg/day, 45 patients with mild-moderate uncomplicated hypertension were treated for 6 weeks in a multicentre, single-blind, randomized, crossover trial. Acebutolol decreased supine systolic blood pressure from 186.5 to 162.7 mmHg and diastolic blood pressure from 107.4 to 92.4 mmHg. Hydrochlorothiazide decreased systolic blood pressure from 185.0 to 166.4 and diastolic blood pressure from 107.2 to 96.4. There was no difference between the effects of acebutolol and hydrochlorothiazide on blood pressure during the trial. Both drugs proved to be safe and effective antihypertensive agents, provided the major contraindications for their use were taken into account. Beta-blockade by acebutolol was highly effective in treating mild-moderate arterial hypertension in the elderly.

Acebutolol↗
PubMed1985

Does endogenous dopamine modulate human sympathetic activity through DA2 receptors?

The effects of placebo and DA2 antidopaminergic agents on basal and stimulated catecholamine (CA) plasma levels in humans have been evaluated by administration either of domperidone or metoclopramide to separate groups of subjects. The latter group was subjected domperidone to sympathetic stimulation by handgrip coldpressor tests, and standing. Pharmacological DA2 receptor blockade, either peripheral by or central and peripheral by metoclopramide, did not modify plasma CA whilst resting or during acute sympathetic stimulation. It is concluded that endogenous dopamine does not seem to play a significant role in modulating NE release in man, at least not under the physiological conditions examined.

Adult↗
PubMed1985

Influence of food on acute and chronic effects of captopril in essential hypertensive patients.

To determine if food reduces the hemodynamic and humoral effects of captopril in patients with essential hypertension, we performed two studies. In the acute study, 15 inpatients with uncomplicated essential hypertension randomly received a single oral dose of placebo or captopril (25 mg) while fasting or after eating, or captopril (50 mg) after eating. Blood pressure and heart rate were measured every 30 min up to 4 h (and up to 10 h in six out of the 15 patients), while plasma renin activity, plasma aldosterone, and serum angiotensin-converting enzyme were measured 2 h after dosing. Compared with placebo, captopril significantly reduced mean blood pressure (p less than 0.001), serum angiotensin-converting enzyme (p less than 0.005), and aldosterone (p less than 0.001), increased plasma renin activity (p less than 0.05), and did not change heart rate; there was no difference between the fasting and the fed state. In the six patients followed up to 10 h, captopril both before and after food significantly and similarly reduced mean blood pressure up to 8 h (p less than or equal to 0.05). In the chronic study, 10 patients with uncomplicated essential hypertension, while having prolonged (3-12 months) treatment with captopril (50 mg twice a day), were asked to take captopril for 1 month 1 h before eating and for another month during or immediately after eating. The sequence was randomized, and blood pressure, heart rate, plasma renin activity, serum angiotensin-converting enzyme, and plasma aldosterone were measured at the end of each period 12 h after last dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Naloxone inhibits sulpiride-induced hyperprolactinaemia in man.

In order to evaluate the interaction between the opiate-like peptidergic pathways and the dopaminergic system in modulating prolactin (PRL) secretion, ten normal volunteers were studied according to a double-blind, cross-over, randomized experimental design. A group of five subjects was given a fixed dose of sulpiride (a selective antidopaminergic agent, 25 mg i.v.) plus either placebo or three different doses of naloxone (a selective opioid antagonist, 0.2, 0.4, 0.8 mg i.v.) while a second group of five subjects received the same drugs in a 'reverse' protocol, i.e. a fixed dose of naloxone (0.4 mg i.v.) plus either placebo or increasing doses of sulpiride (25, 50, 100 mg i.v.). In both groups, the drugs were injected simultaneously and blood samples for PRL determination were taken at various intervals during the 15 min preceding drug injections and then over the following 4 h. Naloxone (0.4 mg i.v.) per se did not induce any modification of plasma PRL levels, but reduced to a significant extent sulpiride-induced hyperprolactinaemia (P less than 0.02). However, a higher dose of naloxone (0.8 mg i.v.) did not cause significant changes in sulpiride-stimulated PRL levels. Increasing dosages of sulpiride (up to 100 mg i.v.) reversed the blunted response of PRL after sulpiride, 25 mg, in presence of naloxone. Our data show that naloxone, at a dose of 0.4 mg i.v. inactive per se on basal PRL levels, is able to blunt significantly sulpiride-induced hyperprolactinaemia. This suggests that, in man, opioid peptides are able to influence PRL release after antidopaminergic stimuli.

Adolescent↗
PubMed1985

Humoral and haemodynamic interactions between clonidine and nifedipine in human essential hypertension.

Acute administration of nifedipine (NIF), a calcium entry blocker (CEB), in animals reduces the hypotensive effect of clonidine (CLN), an alpha-adrenergic agonist. In order to evaluate possible negative interactions between NIF and CLN in man during chronic treatment with these drugs, 12 patients with mild to moderate uncomplicated essential hypertension received either NIF (20 mg twice daily), CLN (0.25 mg once daily), the two drugs together at the same doses, or their matched placebos for a 2-week period each. NIF (-13.5% versus placebo) and CLN (-10.2% versus placebo) decreased blood pressure significantly and when combined, blood pressure was further decreased (-17.1% versus placebo). Heart rate was increased by NIF and NIF + CLN but unchanged by CLN alone. Plasma renin activity (PRA) tended to increase with NIF, decreased with CLN (P < 0.05) and was unchanged with NIF + CLN. Plasma aldosterone did not vary during any of the phases of the trial. These results indicate that NIF and CLN do not interact negatively on blood pressure control in essential hypertensive subjects.

Clonidine↗
PubMed1985

Naloxone does not modify the antihypertensive effect of captopril in essential hypertensive patients.

It has been reported that endogenous opioid antagonism through naloxone (NAL) blunts the hypotensive effect of captopril (CAP) in normal man. For this reason a study was carried out to determine whether NAL interacts with the antihypertensive effect of CAP in patients with mild-to-moderate essential hypertension (n = 6; age 22-43 years). Patients received, according to a randomized code, placebo (PL) during saline infusion, CAP (25 mg orally) during saline infusion, PL + NAL (0.4 mg as a bolus followed by a continuous infusion of 4.0 mg/h for 2 h) and CAP + NAL at the same doses. Three-day intervals elapsed between each phase of the study. Blood pressure (BP) and heart rate (HR) were recorded before (-20 to 0 min) and every 15 min for the next 2 h after drug administration. Blood samples for plasma renin activity (PRA), noradrenaline (NA) and aldosterone (ALD) were collected before (time 0) and 120 min after drug administration. Neither PL nor NAL changed any of the parameters examined, while CAP alone reduced mean BP to a highly significant extent. Naloxone did not change the hypotensive effect of CAP to any significant extent. Captropril, either alone or associated with NAL, tended to reduce plasma ALD and increase PRA (P less than 0.05) without changing HR or plasma NA. These data indicate that, at least under the experimental conditions used, endogenous opioid antagonism does not interfere with the haemodynamic and humoral effect of CAP in essential hypertensive man. This suggests that endogenous opioids do not mediate the pharmacological actions of CAP.

Adult↗
PubMed1985

Angiotensin-converting enzyme inhibitors in hypertension: a review.

Angiotensin-converting enzyme (ACE) inhibitors are a new class of drugs, whose main indications are the treatment of hypertension and of heart failure. Data obtained with captopril, the first orally active ACE inhibitor, affords an understanding of the rationale of their therapeutic use based on the knowledge of their mechanisms of action, efficacy, contraindications and precautions, dosage and frequency of administration, side-effects, interactions and advantages. ACE inhibitors appear to exert their haemodynamic effect mainly by inhibiting the renin-angiotensin-aldosterone system, but also by modulating sympathetic nervous system activity and by increasing prostaglandin synthesis. Therefore they act both on vasoconstrictor and volume factors, since they cause vasodilation (the main effect) and mild natriuresis without affecting the heart rate and contractility and, probably, favourably influencing renal, coronary and cerebral circulation. So far it appears that ACE inhibitors can be usefully employed in the treatment of heart failure, in which they reduce both pre- and after-load, and mainly of hypertension. In the past captopril has been used to treat only severe and or resistant hypertension and some secondary forms, like renal parenchymal and renovascular hypertension, but now it seems that captopril is useful also to treat mild to moderate essential hypertension. Their efficacy in reducing blood pressure is similar to that of thiazide diuretics and of beta-blockers, the two drugs now considered of first choice and they exert their hypotensive action without the development of pseudotolerance or tolerance. ACE inhibitors seem, at the moment, contraindicated in pregnancy and in hyperkalaemic syndromes and must be used with caution in patients with collagen disease (mainly associated with renal failure), with severe bilateral renal artery stenosis (and with severe artery stenosis of a solitary kidney) and with severe sodium depletion. It is now established that captopril has a flat dose response curve and that it must be given (twice daily) at a dose not exceeding 150 mg/day. The same pharmacological approach must be used with future ACE inhibitors in order to establish the right posology and the frequency of administration. In this respect enalapril seems to be a promising ACE inhibitor with a prolonged action (at least 24 hours). The exact posology of ACE inhibitors might be crucial, since it has been shown that the side-effects of captopril (skin rashes, fever, taste disturbances, proteinuria and neutropenia) are dose dependent.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

The influence of selective and nonselective prostaglandin inhibition on renin.

The finding that sulindac, in contrast to indomethacin, does not inhibit renal prostaglandins (PGs) can offer the means to study the role of systemic and/or renal PGs in the control of renin. Therefore we studied, using a randomized cross-over design, the influence of treatment with sulindac and indomethacin on plasma renin activity (PRA) of essential hypertensive patients, which was measured either after standing or after chronic captopril and chlorthalidone administration. In the captopril-treated group, serum thromboxane B2 (TXB2) and urinary 6-keto-PGF1alpha were significantly reduced by indomethacin, while sulindac reduced only serum TXB2. PRA was significantly reduced by indomethacin in the three groups and by sulindac only in standing and captopril-treated patients. These findings suggest that systemic PGs are mainly involved in the control of renin during standing and angiotensin-converting enzyme (ACE) inhibition, while mainly renal PGs play a role in the control of renin during chronic thiazide-like diuretic administration.

Adult↗
PubMed1984

Primary aldosteronism due to adrenal carcinomas.

In the present study two patients with aldosterone-producing adrenal carcinomas are reported. The clinical features were characterized by hypertension and severe hypokalemia with muscular weakness, flaccid paralysis of arms and legs, diarrhea and polyuria. In both cases excessively high plasma aldosterone levels and suppressed plasma renin activity were found. In contrast to most other cases with aldosterone-secreting tumours plasma cortisol, urinary free cortisol excretion, 17-hydroxy- and 17-ketosteroids were in the normal range. There was no clinical evidence of oversecretion of sex hormones. After adrenalectomy blood pressure and serum potassium normalized and the clinical symptoms disappeared. Plasma aldosterone and urinary aldosterone secretion returned to normal, while plasma renin activity remained low. Three and a half and 6 months later primary aldosteronism and the associated clinical symptoms reappeared due to hormonally active metastases. After introducing the antitumour drug o,p'-DDD in patient 1 aldosterone secretion normalized and the clinical status of the patient markedly improved. However, 10 months after diagnosis the patient died due to a haemorrhage from a liver metastasis. In patient 2 tumour-invaded regional lymph nodes were surgically removed with only minor changes in the hormone pattern.

Adrenal Cortex Neoplasms↗
PubMed1984

The influence of indomethacin and sulindac on some pharmacological actions of atenolol in hypertensive patients.

Indomethacin and sulindac were used as tools to study the role of renal and/or systemic prostaglandins in the pharmacological response to atenolol. Patients receiving chronic treatment with atenolol 100 mg received indomethacin 50 mg twice daily or sulindac 200 mg twice daily in a randomised crossover trial. Indomethacin significantly reduced the antihypertensive action of atenolol while sulindac had no effect. The role that systemic and/or renal prostaglandins may play in the antihypertensive action of atenolol is discussed with reference to renal PGI2 production and inhibition of platelet cyclo-oxygenase.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Dose-response relationship of prizidilol hydrochloride (SK&F 92657): a comparison between acute and chronic effects in patients with essential hypertension.

Three different doses (50, 100 and 200 mg) of prizidilol hydrochloride (SK&F 92657), a novel antihypertensive agent with vasodilating and beta-adrenoreceptor blocking properties, were given to three (n = 5) groups of essential hypertensive patients in order to evaluate hypotensive dose-response relationship of the drug and its beta-adrenoreceptor blocking properties. Irrespective of the dose given, acute administration of prizidilol did not effectively decrease blood pressure; however after one-week of treatment prizidilol was effective in reducing blood pressure at both the 100 and the 200 mg b.i.d. schedules. At these doses the drug decreased resting heart rate and plasma renin activity for the first 4-6 h after both acute and steady-state dosing. Similarly postdynamic exercise tachycardia was reduced to a significant extent by the drug; after acute administration this effect lasted 2 h with the lowest dose and 4 h with the highest one. After chronic administration this effect lasted up to 10 h for both the 100 and 200 mg doses. These data indicate that: chronic prizidilol treatment can achieve a satisfactory control of blood pressure in patients with mild-moderate essential hypertension; when prizidilol is administered chronically in hypertensive patients, an equally effective control of blood pressure can be obtained with either a 200 mg b.i.d. or a 100 mg b.i.d. schedule; prizidilol possesses beta-adrenoceptor blocking properties in man which can contribute to its pharmacodynamic activity.

Acetylation↗
PubMed1982

Humoral and hemodynamic effects of increasing doses of captopril in patients with essential hypertension.

To compare the hemodynamic and humoral effects of increasing doses of captopril, blood pressure, heart rate, plasma renin activity, plasma aldosterone and angiotensin-converting enzyme activity were measured in 10 patients with mild uncomplicated essential hypertension before and after captopril given in an increasing dose of 25, 50 and 100 mg twice a day, with each dose given for 3 days. The maximal decrease in blood pressure, which was predicted both by basal plasma renin activity values and by the hypotensive response to the first dose, was found after the lowest (25 mg) dose; this effect was detectable for 12 hours independently of the dose administered. Similarly, plasma renin activity was already maximally increased and plasma aldosterone maximally decreased at the lowest dose, while angiotensin-converting enzyme activity showed a dose-dependent inhibition. These data suggest that (1) neither the magnitude nor the duration of the hypotensive effect nor the resin-stimulating and aldosterone-inhibiting actions of captopril are enhanced by drug doses above 25 mg (at least up to 100 mg), and (2) there was no apparent correlation between the degree of angiotensin-converting enzyme inhibition with increasing doses of captopril and the hypotensive effects of the drug.

Adult↗
PubMed1982

Effect of captopril on renal function in patients with essential hypertension.

The glomerular filtration rate (creatinine clearance), glomerular permeability (qualitative and quantitative proteinuria), tubular reabsorption (k-lambda chains of immunoglobulins and lysozyme) and indexes of tubular cell lysis (alpha-glucosidase and gamma-glutamyltranspeptidase) were measured in the urine of 10 patients with moderate, uncomplicated essential hypertension during placebo therapy and after captopril given at increasing doses of 25, 50, 100 and 200 mg twice daily, the first three doses being given for 3 days and the last one for 4 weeks in all patients and for an additional 6 months in 5 patients. During placebo therapy, proteinuria was absent in eight patients and detectable (glomerular and selective) in two; selective proteinuria appeared in two and a decrease in selectivity was observed in two patients with previous proteinuria after 4 weeks of captopril therapy. No proteinuria was detectable in the five patients followed up to 6 months, not even in the one in whom a decrease in glomerular selectivity had occurred after 4 weeks. The glomerular filtration rate was unchanged as were lysozyme and gamma-glutamyltranspeptidase values, while light chains were always undetectable. Alpha-glucosidase showed some increase; however, increments were transient and always much lower than those observed with known tubular toxic drugs. These data show that under our experimental conditions captopril caused no evident changes in glomerular and tubular function.

Adult↗