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Biomedical subjects

G Leonetti

Publications and source records attributed to G Leonetti.

At least 181 records · Page 10Linked to original sources
PubMed1980

Antihypertensive and renal effects of orally administered verapamil.

In 12 in-patients with moderate uncomplicated hypertension, maintained on constant sodium intake for 15 days, single-blind oral administration of verapamil 80-160 mg t.i.d. for 10 days had a significant antihypertensive effect: in the supine position systolic blood pressure decreased from 177 +/- 5 to 150 +/- 3 mmHg, and diastolic pressure from 111 +/- 3 to 96 +/- 2 mmHg; standing values were similarly lowered from 171 +/- 7 to 143 +/- 4 mmHg, systolic, and from 118 +/- 4 to 97 +/- 2 mmHg, diastolic. The heart rate did not show any significant change (from 79 +/- 3 to 77 +/- 2 beats/min, supine, and from 92 +/- 3 to 87 +/- 3 beats/min, upright). The antihypertensive effect was uniform throughout the day, being similar 2, 3, 6 and 8 h after administration of a dose. Dynamic exercise (75-100 watts on a cycle-ergometer) caused identical increases in arterial pressure and heart rate on the last day of placebo and again on the last day with verapamil, but the peak levels of systolic pressure reached during exercise were lower after verapamil than with placebo, because of the lower blood pressure before exercise. Reduction of arterial pressure by verapamil was not accompanied by increased plasma renin activity, or by renal retention of sodium and water: there was a small increase in sodium excretion, at least during the first days of verapamil administration (from 107 +/- 15 to 113 +/- 15 mEq Na+/day), and a slight significant reduction in body weight (from 74.2 +/- 3.7 to 73.5 +/- 3.7 kg). It is concluded that oral administration of verapamil significantly lowers blood pressure without simultaneously inducing cardiac stimulation, renin secretion or salt and water retention.

Adult↗
PubMed1980

Plasma catecholamines and plasma renin activity at birth and during the first days of life.

1. Plasma noradrenaline and adrenaline concentrations and plasma renin activity were measured in 21 mothers at delivery and in their babies at birth (umbilical cord blood) and on days 1 and 5 of extrauterine life. 2. At birth plasma renin activity was significantly higher in the newborn than in mothers. Plasma renin activity increased further, but not significantly, on day 1 of life and significantly decreased on day 5. On day 5, 10 min head-up tilting caused no change in plasma renin activity. 3. Plasma noradrenaline in the newborn was higher than in mothers at birth and significantly decreased thereafter. Plasma adrenaline levels at birth were similar in the newborn and their mothers and significantly lower in the newborn in subsequent days. Tilting caused no increase in either plasma adrenaline or noradrenaline levels. 4. No correlation was found between plasma noradrenaline and adrenaline levels and plasma renin activity, or between noradrenaline, adrenaline or plasma renin activity and blood pressure.

Blood Pressure↗
PubMed1980

Dose-response curve and time course of the antihypertensive effect of SKF 92 657, a beta-receptor-blocking and vasodilating compound.

1. The antihypertensive effect of the new drug, SKF 92 657, a hydrazinopyridazine derivative, possessing both beta-adrenoreceptor-blocking and vasodilating properties, was investigated in essential hypertension. 2. Single oral doses of 1.0 or 2.0 mg/kg did not produce any consistent decrease in blood pressure; 4.0 mg/kg was the threshold dose for a mild but not significant blood pressure reduction, whereas 8.0 mg/kg caused a significant and marked blood pressure decrease without clinically relevant changes in heart rate. 3. Continued administration of the drug for 7 days induced a significant and uniform reduction in blood pressure without tachycardia. The increase in systolic blood pressure and in heart rate caused by dynamic exercise was left unaffected by the drug.

Adrenergic beta-Antagonists↗
PubMed1979

Plasma catecholamines and blood pressure responses to the carotid baroreceptor reflex in essential hypertension.

1. Slight decreases and increases in carotid baroreceptor activity were induced in subjects with essential hypertension by slight alterations in carotid transmural pressure (variable pressure neck-chamber technique) in order to obtain limited increases and reductions in sympathetic adrenergic activity. 2. When sympathetic activity was reflexly increased there was a rise in arterial pressure but no significant increase in plasma catecholamines. Likewise when sympathetic activity was reflexly reduced there was a fall in arterial pressure but no significant reduction in plasma catecholamines. 3. Plasma noradrenaline and adrenaline significantly and markedly increased in the same subjects when sympathetic activity was increased by activation of both arterial and low pressure baroreceptor reflexes with tilting. 4. It is suggested that measurements of catecholamines in systemic plasma may reveal marked degrees of sympathetic activation but may not be a sensitive index of more moderate changes in sympathetic tone.

Adult↗
PubMed1978

Relationship between the hypotensive and renin-stimulating actions of diuretic therapy in hypertensive patients.

1. The pressor role of renin stimulated by chronic diuretic therapy has been assessed in 31 patients with essential hypertension by infusing the angiotensin II antagonist, saralasin, immediately before and at the end of 2 weeks' treatment with the diuretic, chlorthalidone. 2. Under diuretic therapy the change in blood pressure caused by saralasin was found to be correlated to plasma renin activity values, in such a way that small pressor responses were again observed in patients whose renin was mildly stimulated by the diuretic, whereas a marked depressor response occurred in patients whose renin was markedly increased. 3. On the other hand, the hypotensive effect of chlorthalidone was correlated to values of plasma renin activity under diuretic therapy in an opposite direction: indeed little or no decrease and sometimes an increase in blood pressure were observed in patients with marked renin activation by diuretic therapy. 4. It is concluded that stimulation of renin release by chronic diuretic therapy can be considered a factor limiting the hypotensive activity of diuretic drugs.

Adult↗
PubMed1978

Considerations on physiopathological approaches to the treatment of hypertension.

1. Two main physiopathological approaches to the treatment of hypertension are discussed, the first based on renin profiling and the second on haemodynamic measurements. 2. Reduction in plasma renin activity does not appear to be a clinically important mechanism in the hypotensive effect of beta-adrenergic blockers and of alpha-methyldopa. In particular, alpha-methyldopa has been found equally effective as a hypotensive agent both in normal renin and in low renin hypertensive patients. 3. Diuretics are certainly possessed of a renin-stimulating action, but in most patients this action does not obscure the hypotensive effect of these drugs. 4. Responders and non-responders to the hypotensive activity of beta-adrenergic blockers do not differ among them in their control haemodynamics.

Adrenergic beta-Antagonists↗