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Biomedical subjects

E Ambrosioni

Publications and source records attributed to E Ambrosioni.

At least 19 recordsLinked to original sources
PubMed1992

Perindopril versus captopril: efficacy and acceptability in an Italian multicenter trial.

The aim of this 3-month, double-blind, double-dummy, parallel group study was to compare the antihypertensive efficacy and acceptability of perindopril (4-8 mg/day) in 54 patients (30 males, 24 females, 25-68 years of age) and captopril (50-100 mg/day) in 54 patients (39 males, 15 females, 29-66 years of age) in the treatment of essential hypertension. In a subgroup of 38 patients a complete echocardiographic study was performed. The two groups had similar (ANOVA) blood pressure (BP), heart rate (HR), body mass index, and duration of hypertension. Supine and standing BP was significantly reduced by both drugs, without differences between them. Owing to poor control of BP, hydrochlorothiazide (25 mg/day) was added to 27% of patients on perindopril and to 41% of patients on captopril (p less than 0.05). Normalization of supine diastolic BP (less than or equal to 90 mm Hg) was obtained in 67% of patients on perindopril and in 47% of patients on captopril (p less than 0.01). No change in HR was detected. Only mild untoward effects were recorded. Left ventricular mass was significantly reduced by either drug, with no change in systolic function. In conclusion, perindopril and captopril, at these doses, were both well tolerated and on average reduced BP to a similar extent; however, treatment with perindopril showed that fewer patients needed the addition of a thiazide and BP became normal in a larger number of patients.

Adult↗
PubMed1992

ACE-inhibitors and atherosclerosis.

The involvement of the circulating and local renin-angiotensin system in atherosclerotic process has been hypothesized on the basis of experimental data showing presence and specific actions of the components of this system in the vascular wall. In particular, angiotensin II may participate in well known events in atherogenesis as the control of smooth muscle cell growth and proliferation. Recent studies have shown an effect of angiotensin converting enzyme (ACE) inhibition on the development of atherosclerosis in animal models. Captopril and cilazapril prevent myointimal proliferation after vascular injury in rat. Captopril reduces aortic cholesterol content and percentage intimal aortic surface covered by lesions in Watanabe heritable hyperlipidemic rabbits. Captopril also significantly reduces the progression of carotid and coronary lesions in monkeys fed a high cholesterol diet. In addition, a role for converting enzyme inhibitors in reducing aortic and microvascular growth either in hypertensive or normotensive rats has been demonstrated. It is possible that ACE-inhibitors prevent angiotensin II-induced vascular proliferation and thereby suppress the development of atherosclerosis in animals. It is also conceivable that the blood pressure effects of ACE-inhibitors could play a role in the antiatherosclerotic effect shown by these drugs, even though this explanation cannot be addressed by studies dealing with normotensive animals. Then, other mechanisms could be involved, including hypothesized effects of blockade of the renin-angiotensin system on sympathetic nervous system activity, regulation of vascular growth factors and insulin sensitivity. The clinical significance of these experimental findings is unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1992

Factors associated with acute salt-sensitivity in borderline hypertensive patients.

The acute sensitivity to sodium loading has been investigated in 26 borderline hypertensive patients (BHT) undergoing acute i.v. NaCl infusion. Measurements included blood pressure (BP), forearm vascular resistance (FVR) and venous distensibility (VV30), plasma renin activity (PRA), plasma aldosterone, plasma atrial natriuretic factor (ANF), and plasma levels of endogenous Na+/K+ATPase inhibitor. Sodium loading was associated with a greater than 8% increase in mean BP in 12 patients defined as salt-sensitive (NaCl-SENS) in comparison to salt-insensitive (NaCl-INSENS) subset. NaCl-SENS patients in comparison to NaCl-INSENS exhibited 1) a greater baseline VV30 (2.1 vs 1.4 ml/100 ml; p less than .005), and a response to saline characterized by 2) increased FVR (21.4 vs -6.5%; p less than .005), 3) blunted PRA suppression (-42 vs -67%; p less than .05), 4) delayed ANF response and 5) release of a Na+/K+ATPase inhibitor. Post-loading cumulative urinary sodium excretion was reduced in NaCl-SENS borderline hypertensives compared to NaCl-INSENS (2.6 vs 3.8 mumol/min/Kg; p less than .05). We conclude that acute salt-sensitivity in BHT is characterized by a blunted hormonal response to sodium loading which could be responsible of the activation of hemodynamic as well as humoral mechanisms leading to progressive blood pressure increase.

Adult↗
PubMed1992

ACE inhibition in diabetic patients: effect on pressor responsiveness to noradrenaline.

The pressor responsiveness to noradrenaline was assessed before and after four weeks of treatment with enalapril (20 mg/day) in eight mild-to-moderate essential hypertensives, in eight normotensive type II diabetics and in eight mild-to-moderate hypertensive type II diabetic patients. The ACE inhibitor interfered to the same extent with the renin-angiotensin system and did not alter noradrenaline kinetics in the three groups of patients, but significantly reduced the arterial responsiveness only in non-diabetic subjects. It is suggested that factors, such as an exaggerated sodium retention, might determine the lack of effect of enalapril in diabetic patients.

Adult↗
PubMed1992

[The Study Group of Quinapril in Arterial Hypertension. The Steering Committee].

The efficacy and safety of the treatment of arterial hypertension with the ACE-inhibitor quinapril, were evaluated in a multicentre study conducted in Italy. The study, lasting 14 weeks, after a preliminary wash-out period, allowed response-based titration of quinapril dose from 10 mg to 40 mg once a day, with provision to combine additional hydrochlorothiazide (12.5 to 25 mg), in case of persistently high diastolic pressure levels. The efficacy sample included 1267 patients: at therapy week 14, 78.6% of patients were treated with quinapril alone. Global response rate (intent-to-treat) was 83.3%, with a mean reduction of diastolic pressure of 15.8 mmHg (95% confidence interval from 15.5 to 16.2 mmHg). 91 patients reported 126 associated adverse events (7.0%); the most frequently reported event was cough (2.7%). First-dose hypotension was rarely reported (1.3%), even in elderly and diabetic patients.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Early treatment of acute myocardial infarction with angiotensin-converting enzyme inhibition: safety considerations. SMILE pilot study working party.

The use of angiotensin-converting enzyme (ACE) inhibitors in acute myocardial infarction (AMI) is based on their capacity to limit ventricular enlargement and dysfunction. To date, the safety profile of administration of ACE inhibitors early in the course of AMI has not been established. In-hospital and long-term consequences of treatment with the ACE inhibitor zofenopril initiated within 24 hours of the onset of symptoms were compared with those of standard treatment in an open-label trial involving 204 patients with AMI who were not undergoing thrombolytic treatment. Zofenopril promptly blocked ACE activation. Blockade was almost complete (91 +/- 6%) after 72 hours and paralleled decreases in systolic blood pressure. Systemic blood pressure was acutely reduced by zofenopril, and severe but reversible hypotension occurred in 15% of hospitalized patients and in 3% of those treated over the long term. No adverse clinical or biochemical events were reported during the course of zofenopril therapy. Overall cardiovascular mortality was not significantly reduced by early zofenopril compared with placebo therapy (7.8% vs 10.7% [difference not significant]). The inhospital incidence of acute left ventricular failure and ventricular arrhythmias decreased by 63% and 39%, respectively, among zofenopril-treated patients, who also reported fewer anginal episodes both acutely (68% reduction) and over the long term (56% reduction) and did not require as much drug treatment (i.e., diuretics, digoxin, and/or anti-ischemic agents) during the follow-up phase. Left ventricular size decreased and ejection fraction (EF) increased in patients who received zofenopril, and the improvement was greater among patients with poorer ventricular function (EF less than 40%). Early administration of ACE inhibitors may therefore constitute a safe form of therapy for patients with AMI, particularly when the event is complicated by clinical signs or evidence of ventricular dysfunction.

Administration, Oral↗
PubMed1991

The effect of ace inhibition on peripheral hemodynamics in normotensive and hypertensive patients with type II diabetes.

The effect of treatment with enalapril (10 days at 10 mg/d followed by 4 weeks at 20 mg/d) on forearm hemodynamics was assessed in eight normotensive patients and eight patients with hypertension affected by Type II diabetes as well as in eight patients with essential hypertension and normal glucose tolerance. The ACE inhibitor decreased regional vascular resistances and increased the maximum arteriolar-vasodilating capacity and venous distensibility in the three groups of patients. Thus, this study shows that ACE inhibition by enalapril improves regional hemodynamics in patients with Type II diabetes.

Adult↗
PubMed1991

Flecainide: evidence of non-linear kinetics.

The pharmacokinetics of flecainide has been studied in 12 patients with ventricular arrhythmias, both after single administration and during chronic treatment. Both the half-life and the AUC were significantly increased during chronic treatment. This suggests that the kinetics of flecainide might be non-linear also in patients with normal kidney and liver function. The increase in plasma flecainide levels during chronic treatment could not be predicted, so close monitoring of its plasma levels is advisable.

Adult↗
PubMed1991

Atrial natriuretic factor modulates the plasma levels of a Na+/K+ATPase inhibitor in volume expanded borderline hypertensives.

To evaluate the existence of a relationship between atrial natriuretic factor (ANF) and plasma Na+/K+ATPase inhibitory activity in humans, we examined the hemodynamic and humoral response to volume expansion in 41 borderline hypertensive patients (BHT) with either normal (n = 33) or low plasma renin activity (n = 8). The study was carried out by measuring blood pressure, forearm circulation, plasma renin activity (PRA), ANF, and plasma levels of an endogenous Na+/K+ATPase inhibitor before and after 2 h of acute intravenous NaCl infusion (0.22 mL/min/kg bodyweight). The early (45 min) changes of ANF and those of Na+/K+ATPase inhibitory activity attained at the end of saline infusion were inversely related in BHT with normal PRA and directly related in the low-PRA population (r = 0.64). The time-course of ANF response to sodium loading was significantly delayed in BHT characterized by normal venous distensibility. They also showed a greater increase in plasma Na+/K+ATPase inhibitory activity occurring with an hypertensive, vasoconstrictive, and sodium retaining response as well. We conclude that in normal PRA borderline hypertensives, ANF may modulate the release of a plasma Na+/K+ATPase inhibitor in a setting where extracellular volume is acutely expanded. Our findings also suggest that dissimilarities in peripheral venous distensibility are able to influence the time-course of ANF response. The blunted ANF increase observed in response to NaCl loading in a subset of BHT could represent an early marker of the attitude of such patients to develop high blood pressure leading to the release of a Na(+)-pump inhibitor and influencing individual salt-sensitivity.

Adult↗
PubMed1991

Plasma concentrations of atrial natriuretic factor and hemodynamics in pregnancy-induced hypertension.

Plasma values of atrial natriuretic factor (ANF) were evaluated in 31 women with pregnancy-induced hypertension (PIH) and 31 normal pregnant women at the same age of gestation. In 27 women with PIH and 27 normal pregnant women forearm venous tone (FVT) was evaluated by Strain Gauge Plethysmography. Forearm vascular resistance (FVR) was measured as the ratio of mean blood pressure (MBP) to forearm blood flow. In addition Cardiac Index (CI) by means of transthoracic electrical bioimpedance and total peripheral vascular resistance (TPR) (with the Frank Equation) were also measured. In comparison with the normal pregnant women, the women with PIH had similar values of hematocrit (as an index of plasma volume) and significantly higher levels of FVR and TPR, while ANF plasma values did not differ significantly. Subdividing the women with PIH in relation to the presence of proteinuria (greater than or equal to 0.3 g/l), those with proteinuria, in addition to significantly higher levels of FVR and TPR, had significantly higher levels of FVT than normal pregnant women, while ANF plasma values were higher even though the difference was only near the level of significance. Hypertensive women with proteinuria also had higher values of FVT than hypertensive women without proteinuria. By means of multiple regression ANF did not show any significant correlations with hematocrit or sodium excretion. Hypertension with proteinuria seems to represent a more severe form of the disease in which, in addition to the probable influence of other factors such as the renin-angiotensin and prostaglandin systems, a greater increase in peripheral sympathetic tone than in hypertension alone appears to be present, causing a reduction in venous compliance in addition to the elevation in FVR and TPR, with increase in central blood volume and atrial stretch. This may explain the higher ANF plasma levels in these patients in comparison with normal pregnant women, even though the absence of a significant correlation of ANF with hematocrit and the fact that ANF increase was only near the level of significance may suggest a change in the relation between ANF secretion and atrial volume receptors in pregnancy either normal or complicated by hypertension. ANF does not seem to play an important role in water and sodium excretion in PIH probably because of the presence of very high plasma levels of hormones such as aldosterone, progesterone and oestriol which, together with renal prostaglandins, seem to be involved in diuresis and natriuresis in pregnancy.

Adult↗
PubMed1991

[Thrombolytic drugs in acute myocardial infarct].

Thrombolytic therapy has a primary role in modifying evolving acute myocardial infarction by restoration of patency of infarct-related artery. All thrombolytic agents convert plasminogen to plasmin; 3 of them (streptokinase, urokinase and anisoylated human plasminogen streptokinase activator complex-APSAC) are not specific for fibrin and 2 (rt-PA, scu-PA) are relatively clot-specific and have limited systemic fibrinolytic activity. To date, the largest experience has been with streptokinase, which is derived from streptococci and therefore has the potential to cause allergic reactions, more frequent with repeat doses of the drug. Streptokinase is not clot-selective; despite significant systemic fibrinolysis, which is an usual consequence, major bleeding complications are uncommon. Another problem with streptokinase is hypotension, which depends on infusion rate. APSAC differs from the parent streptokinase-plasminogen complex with kinetics well suited to a sustained thrombolytic effect. Although it was expected to have clot selectivity, this feature is missed at the dose needed in the treatment of acute myocardial infarction. rt-PA is a natural occurring serum protease which presents important clot specificity with limited systemic fibrinolytic activity. However, the risk of major bleeding is not less than that observed with thrombolytic agents without clot selectivity. Of considerable interest is the potential for urokinase and prourokinase to act synergistically with other thrombolytic agents, with hypothetic improvement in efficacy and safety of thrombolytic therapy. Despite some different features among various thrombolytic agents, they are equally safe and effective in salvaging myocardium and in assuring survival benefit after acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Anistreplase↗
PubMed1991

Pharmacokinetics of a controlled release preparation of naproxen.

The pharmacokinetics of a controlled release preparation of naproxen (750 mg) was compared with that of standard release naproxen, in 12 healthy volunteers. The plasma levels of naproxen and urinary recoveries of naproxen and metabolites were determined both after single doses and chronic administration. The experimental data show that the bioavailability of the controlled release preparation is equal to that of standard release naproxen; however, the controlled release preparation allows more constant plasma levels of naproxen and, when administered once a day for prolonged periods, is capable of maintaining effective concentrations for most of the dosing period.

Adult↗
PubMed1991

[Significance of the degree of oxidative hepatic metabolism in conditioning the pharmacokinetics and the pharmacodynamics of propafenone].

The aim of this study was to evaluate plasma concentrations of propafenone (P) and 5-hydroxy-propafenone (5-OH-P) at steady state in 36 patients with ventricular premature beats, Lown class greater than or equal to 2, submitted to antiarrhythmic treatment with propafenone either in acute administration (AA) (300-450 mg) or in chronic administration (CA) (150-300 mg t.i.d. for 14-21 days followed by a wash out), and to define the relationship existing between metabolic oxidative capacity and P and 5-OH-P pharmacokinetics and pharmacodynamics. Antiarrhythmic treatment resulted efficacious in 31/36 cases (86%) during AA and in 28/36 cases (78%) during CA. At steady state a wide interindividual variability was observed in plasma concentrations of P (mean = 835 +/- 619 ng/ml, coefficient of variation = 74%), in plasma concentrations of 5-OH-P (mean = 142 +/- 93 ng/ml, coefficient of variation = 65%) and of their ratio (mean = 6.51 +/- 8.53, coefficient of variation = 131%), without significant differences between responders and nonresponders. In a subgroup of 14 subjects, characterized as extensive oxidizers of dbrisoquine, a significant correlation (r = 0.97, p less than 0.001) was observed between the ratio of P and 5-OH-P plasma concentrations at steady state and oxidative metabolic capacity (expressed as debrisoquine/4-hydroxy-debrisoquine ratio). Oxidative metabolic capacity was also correlated with P half life (r = 0.82, p less than 0.002 in AA and in CA) and with the ratio of P and 5-OH-P area under curve (r = 0.91, p less than 0.001 in AA and r = 0.90) changes at the electrocardiogram (mean values = + 20% for QRS, +26% for PR). In conclusion, oxidative metabolic pathway is a crucial point in propafenone metabolization; indeed the extent of metabolic oxidative capacity, evaluable by analysis of debrisoquine oxidation, is responsible for a wide interindividual variability of P and 5-OH-P plasma concentrations, present even in a population of debrisoquine extensive oxidizers and, moreover, influences the extent of electrocardiographic changes of PR and QRS intervals, which are related to 5-OH-P plasma levels, but not to P plasma levels.

Adult↗
PubMed1990

Pattern of peripheral venous response to volume expansion in borderline systemic hypertension.

An increased venous tone responsible for changes in systemic hemodynamics has been described in borderline hypertensive patients along with the release, in response to intravenous sodium chloride, of an endogenous sodium ion/potassium ion adenosine triphosphatase (Na+/K+ ATPase) inhibitor with vasoconstrictive properties. The hemodynamic and humoral effects of a 2-hour intravenous saline infusion were studied in 25 borderline hypertensives characterized on the basis of their forearm venous distensibility (VV30) in normal (n = 15) and low (n = 10) VV30. VV30 was slightly reduced by saline in the entire hypertensive group (1.47 vs 1.36 ml/100 ml; p less than 0.05), whereas blood pressure and plasma Na+/K+ ATPase inhibitor were unchanged. Normal VV30 showed a sudden increase in plasma Na+/K+ ATPase inhibitor in response to saline associated with an increase in blood pressure, a forearm arterial and venous constriction, and a sluggish suppression in plasma renin activity, whereas low VV30 exhibited a completely opposite pattern. The changes in plasma Na+/K+ ATPase inhibitor inversely correlated to VV30 decreases in borderline hypertensives with normal VV30 (r = -0.49; p less than 0.05), whereas they did not in all hypertensive patients. Atrial natriuretic peptide response to saline infusion was delayed in normal VV30 and inversely related to the changes in Na/K+ ATPase inhibitory activity (r = -42; p less than 0.05) attained after 2 hours of infusion in the entire hypertensive population. Results of this study suggest the ability of acute volume expansion to reduce peripheral venous distensibility in borderline hypertensive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Purification of a Na+/K+ ATPase inhibitor from borderline hypertensives' plasma.

Increasing experimental evidences suggest an involvement of an endogenous Na+/K+ ATPase inhibitor in regulating water and electrolytes balance as well as in the pathogenesis of hypertension. However, conflicting results on the nature and the chemical structure of this substance still make it difficult to understand exactly its physiological mechanism of action. In the present study an attempt was made to purify a Na+/K+ ATPase inhibitor from hypertensives' plasma by solid phase extraction followed by 2 HPLC steps using reverse and normal phase columns. The fractions, from both columns, were able to inhibit Na+/K+ ATPase, 3H-ouabain binding to enzyme, ouabain sensitive 86Rb uptake and pNPPase activity in a manner not affected by boiling. Ultrafiltration experiments demonstrate that inhibitory activity is largely due to a low-molecular weight substance. These findings seem to confirm the presence in hypertensives plasma of a Na+/K+ ATPase inhibitor with some similarities with ouabain.

Chromatography, High Pressure Liquid↗