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Biomedical subjects

G A Zaal

Publications and source records attributed to G A Zaal.

14 recordsLinked to original sources
PubMed1977

Haemodynamic characteristics of low-renin hypertension.

1. Intra-arterial pressure, cardiac output, renal blood flow and glomerular filtration rate were measured in 19 patients with low-renin hypertension and in 30 patients with normal-renin hypertension. 2. Cardiac output and renal blood flow were significantly lower in low-renin hypertension. Total peripheral and renal vascular resistance were markedly higher in this group. 3. Plasma renin concentration correlated inversely with both total peripheral and renal vascular resistance as well as with age. Multiple regression analysis indicated that part of the relationship between renin and haemodynamic variables did not depend on age. Furthermore, plasma renin concentration did not decrease with age in a group of 40 normotensive control subjects of similar age to the hypertensive patients. 4. The results provide further confirmation that renin decreases as hypertension progresses.

Blood Pressure↗
PubMed1976

Follow-up of renin in essential hypertension.

1. Twenty-three subjects with essential hypertension were followed for a period of up to 7 years. They were untreated during the investigations. 2. Plasma renin concentration was found to decrease temporarily in some subjects. The ultimate change was a gradual rise. In those subjects who suffered myocardial infarction renin tended to rise more sharply. 3. A relationship was established with the rise in renal vascular resistance, which almost invariably occurred over the years.

Adult↗
PubMed1976

Haemodynamic and endocrinological changes during anti-hypertensive treatment with a new vasodilator substance (L6150) and propranolol.

1. In eighteen subjects with mild to moderate hypertension the effectiveness of the new vasodilator drug L6150 (Lepetit) was studied. Its mechanism of action was identified by systemic and renal blood flow measurements and by estimating changes in plasma renin and aldosterone concentration and plasma volume. The reflexly induced hyperkinetic circulatory state could be completely corrected by adding propranolol or prevented by pretreatment with the latter drug. 2. Sodium retention was an invariable phenomenon. It was not due to a stimulation of the reninangiotensin-aldosterone axis since plasma aldosterone was significantly decreased, presumably as a consequence of plasma volume expansion.

Adult↗
PubMed1976

Haemodynamic and endocrine changes during anti-hypertensive treatment with clonidine and its derivative St 600.

1. The cardio-renal haemodynamic and endocrine effects of the anti-hypertensive agents 2-(2,6-dichlorophenylamine)-2-imidazoline hydrochloride (clonidine, St 155) and 2-(5-fluor-o-toluidine)-2-imidazoline hydrochloride (St 600) were investigated in twelve patients with essential hypertension. 2. The anti-hypertensive action of both compounds was similar and was accompanied by a reduction in heart rate and in cardiac output, total peripheral resistance being unchanged. There was no alteration in renal blood flow and glomerular filtration rate, and renal vascular resistance showed a significant decrease. Blood volume and plasma renin concentration did not change significantly. An inverse relation changes in plasma volume and plasma aldosterone concentration was observed. In the face of similar reductions in blood pressure, no differences were observed between systemic and renal haemodynamic and endocrine responses after clonidine and St 600.

Cardiac Output↗
PubMed1976

Follow-up of renin in essential hypertension.

In a prospective study of patients with essential hypertension, plasma renin levels showed a progressive increase with longer follow-up. This was associated with a parallel increase in renal vascular resistance. Arterial blood pressure and plasma volume did not change significantly during follow-up. In patients where the hypertension was complicated by myocardial infarction there was a comparatively greater increase in renin levels and renal vascular resistance which may be attributable to chronic reduction of cardiac output.

Adult↗
PubMed1975

Comparison between the effects of ST 600 and catapres.

The effects of the antihypertensive imidazoline compounds 2-(5 fluor-0-toluidine)-2-imidazoline hydrochloride (ST 600) and 2-(2, 6 dichlorophenylamine)-2-imidazoline hydrochloride (ST 155, catapres) on intra-arterial pressure, cardiac output, stroke volume, heart rate, total peripheral resistance, renal blood flow, glomerular filtration rate, renal vascular resistance, plasma volume, plasma renin and aldosterone concentration were studied in five patients with essential hypertension. The antihypertensive action of both compounds was similar and was accompanied by a reduction in heart rate and in cardiac output, total peripheral resistance being unchanged. There was no significant decrease in renal blood flow and glomerular filtration rate. Plasma volume and plasma concentrations of renin and aldosterone also did not change significantly. In the face of similar reductions in blood pressure, no differences were observed between cardio-renal haemodynamic responses after ST 600 and catapres. However ST 600 had a longer lasting effect (8-12 hours).

Adult↗
PubMed1975

Comparison between the effects of ST 600 and clonidine.

The effects of the antihypertensive imidazoline compounds 2-(5 fluor-0-toluidine)-2-imidazoline hydrochloride (ST 600) and 2-(2, 6 dichlorophenylamine)-2-imidazoline hydrochloride (ST 155, clonidine, Catapres) on intra-arterial pressure, cardiac output, stroke volume, heart rate, total peripheral resistance, renal blood flow, glomerular filtration rate, renal vascular resistance, plasma volume, plasma renin and aldosterone concentration were studied in five patients with essential hypertension. The antihypertensive action of both compounds was similar and was accompanied by a reduction in heart rate and in cardiac output, total peripheral resistance being unchanged. There was no significant decrease in renal blood flow and glomerular filtration rate. Plasma volume and plasma concentrations of renin and aldosterone also did not change significantly. In the face of similar reductions in blood pressure, no differences were observed between cardio-renal haemodynamic responses after ST 600 and clonidine. However ST 600 had a longer lasting effect (8-12 hours).

Adult↗