PubMed Health⌕ Search

Biomedical subjects

J Staessen

Publications and source records attributed to J Staessen.

At least 199 records · Page 11Linked to original sources
PubMed1984

Responses of the systemic circulation and of the renin-angiotensin-aldosterone system to ketanserin at rest and exercise in normal man.

The systemic circulation at rest and during exercise was studied in ten normal male volunteers, after placebo on one occasion and after acute intravenous administration of the serotonergic antagonist ketanserin on another occasion. The effects of ketanserin on the components of the renin-angiotensin-aldosterone system, on plasma catecholamines and on exercise capacity for graded uninterrupted exercise were also investigated. At rest in recumbency rapid intravenous injection of 10 mg of ketanserin, followed by a continuous infusion of 2 mg/h, produced an acute but transient fall in mean intra-arterial pressure of 6 mmHg compared with placebo. After 15 min the mean arterial pressure with ketanserin was within 2 mmHg of the mean pressure with placebo. In the sitting position both at rest and up to 30% of maximal work rate, the mean arterial pressure during ketanserin did not differ from the pressure on placebo. However, at higher levels of physical activity the rise in mean arterial pressure was lower with ketanserin; the pressure achieved with placebo was 7.5 mmHg higher at maximal work rate. Heart rate and cardiac output were significantly higher during ketanserin. When the subjects were lying down and resting, plasma noradrenaline and adrenaline levels, plasma renin activity and angiotensin II concentration were not affected by ketanserin; however, these values were higher in the sitting position both at rest and during exercise. Plasma aldosterone was reduced by ketanserin during exercise and also when the subject was resting in the recumbent position.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Racial differences in intracellular concentration and transmembrane fluxes of sodium and potassium in erythrocytes of normal male subjects.

Erythrocyte concentrations and fluxes of sodium and potassium were investigated in normal black and white male subjects. Erythrocyte sodium concentration was significantly elevated in blacks compared to whites. In single regression analysis erythrocyte sodium concentration was inversely related to the ouabain-sensitive 86Rb-uptake and to the frusemide-sensitive sodium efflux. After adjusting for race, only the relationship between the erythrocyte sodium concentration and the Na+, K+-ATpase pump activity persisted. The sodium-lithium countertransport system was also depressed in the black subjects. No significant difference was observed in erythrocyte potassium concentration between blacks and white. It is probable that, in blacks the decreased active influx of potassium through the sodium-potassium pump was to some extent counter balanced by a reduced efflux of this cationic mediated by the depressed cotransport system. There was no difference in cationic concentrations and fluxes of sodium and potassium between blacks bearing and not bearing haemoglobin S.

Adult↗
PubMed1984

A population study on the relationship between blood pressure and the excretion of urinary cations.

The relationships between blood pressure and the 24-h excretion of three urinary cations (Ca2+, K+, and Na+) were investigated in a random sample of 528 adults (greater than or equal to 20 years) inhabitants of two Belgian towns. In these adults both systolic and diastolic blood pressures were strongly and independently correlated with age and body weight. Systolic pressure in women was significantly and positively related to pulse rate. After adjusting for age and body weight, systolic and diastolic pressures in men were significantly (p less than 0.001 and p less than 0.01, respectively) and negatively correlated with urinary potassium excretion. Diastolic pressure in men was weakly (p less than 0.05 after adjusting for body weight, age, and urinary potassium excretion) but positively correlated with calcium excretion. In a subsample of 162 premenopausal women, blood pressure was higher in current contraceptive pill users than in women not taking oral contraceptives. In 56 current pill users there was a positive association between systolic pressure and 24-h urinary sodium (p less than 0.01 after adjusting for age, body weight, and pulse rate). The present study indicates that urinary potassium is a consistent and negative predictor of both systolic and diastolic pressures in adult men, whose diastolic pressure is weakly and positively associated with urinary calcium. The positive association between systolic pressure and urinary sodium in current users of contraceptive pills may suggest that their blood pressure becomes responsive to their usual salt intake.

Adult↗
PubMed1984

Haemodynamic and humoral responses to chronic ketanserin treatment in essential hypertension.

Ketanserin (120 mg/day) or placebo was given orally to 14 patients with mild to moderate essential hypertension according to a double blind crossover protocol, each treatment period lasting six weeks. Resting intra-arterial pressure in the recumbent position was reduced from 150/84 to 141/77 mm Hg; the hypotensive effect persisted throughout an uninterrupted graded exercise test to the point of exhaustion. The haemodynamic effects were similar at rest and during exercise. Overall, systemic vascular resistance decreased by 14%, heart rate fell by 5%, but stroke volume and cardiac output increased. Mean pulmonary arterial pressure and capillary wedge pressure were not significantly affected, but pulmonary vascular resistance decreased by 15%. The pressor response to methoxamine was significantly reduced by ketanserin. Both plasma noradrenaline and adrenaline concentrations increased, plasma renin activity and angiotensin II concentration decreased, and plasma aldosterone concentration was unchanged. The data indicate that ketanserin induces arteriolar dilatation, possibly related to an alpha-1-antagonistic action and to a reduced circulating angiotensin II concentration. The haemodynamic response is complex, and an increase in cardiac output limits the hypotensive effect. There is no firm evidence of an effect on venous tone as cardiac filling pressures do not change.

Adult↗
PubMed1984

Cardiac structure and function in cyclists and runners. Comparative echocardiographic study.

Twelve cyclists and 12 long distance runners matched for age, height, and weight with two control groups of 12 non-athletes were studied echocardiographically to evaluate cardiac structure and function. Runners weighed 8 kg less than cyclists, but age and height were similar. Peak oxygen uptake per kg body weight was higher in athletes than in the control subjects but was similar in the cyclists and in the runners. The athletes' hearts had a larger end diastolic left ventricular internal diameter, mean wall thickness, and cross sectional area of the left ventricular wall than those of the respective control subjects. Nevertheless, whereas the left ventricular internal diameter was not different between the cyclists and runners, mean wall thickness and cross sectional area of the left ventricular wall were greater in the cyclists even after adjustment for weight. The ratio of wall thickness to left ventricular internal radius was significantly larger in cyclists than in their control group, but the ratio was similar in runners and their control group. The echocardiographic indices of left ventricular function were similar in the athletes and the control groups. Systolic left ventricular meridional wall stress was lower in the cyclists than in the runners. The data suggest that runners develop an increase in left ventricular wall thickness which is proportionate to the internal diameter but that in cyclists the increase is disproportionate because of the isometric work of the upper part of the body during cycling.

Adolescent↗
PubMed1984

Urinary cadmium and lead concentrations and their relation to blood pressure in a population with low exposure.

The 24 hour urinary excretion of cadmium (U-Cd) and lead (U-Pb), and the excretion of beta-2- microglobulins and retinol binding protein concentration in spot urines, were determined in a random 4% sample of the population of a small Belgian town. Blood pressure and body weight were measured on two separate occasions. U-Cd averaged 2.4 nmol/24 h in 46 youths, increased with age, and was significantly higher in 57 adult men as compared with 59 women (9.3 v 7.2 nmol/24 h; p less than 0.01). U-Pb averaged 28 nmol/24 h in youths and similarly increased with age: adult men excreted more lead than women (64 v 40.0 nmol/24 h; p less than 0.001). Among men, manual workers excreted more cadmium (12.6 v 7.5 nmol/24 h; p less than 0.05) but a similar amount of lead (62 v 61 nmol/24 h) compared with office workers. After adjusting for sex and age, U-Cd and U-Pb were not related to body weight and cigarette consumption. In simple regression analysis, U-Cd was positively correlated with both systolic (r = +0.30; p less than 0.05) and diastolic (r = +0.38; p less than 0.01) blood pressure in women. After adjusting for other contributing variables, however, a weak but negative relation became apparent between systolic pressure and U-Cd in women (t = -2.21; p = 0.033) and between diastolic pressure and U-Cd in men (t = -2.04; p = 0.047). In women urinary beta-2-microglobulin was related to diastolic pressure (r-0.44; p<0.01) and after adjusting for age to both systolic (t=2.75; p=0.009) and diastolic (t=-3.07; p=0.004) pressure. In none of the sex-age groups did U-Pb and retinol binding protein contribute to the blood pressure variability.

Adolescent↗
PubMed1984

Hemodynamic and humoral effects of prostaglandin inhibition in exercising humans.

This double-blind placebo-controlled study investigated whether indomethacin-induced (500 mg/3 days) prostaglandin synthesis inhibition (PG inhibition) affected systemic hemodynamics and several humoral factors in nine sodium-replete normal humans, during exercise. Independent of the level of physical activity, PG inhibition was accompanied by small but significant (P less than 0.001) increases in systolic (+4.3 mmHg) and diastolic (+1.8 mmHg) intra-arterial pressure: the changes in cardiac output (determined noninvasively), systemic vascular resistance, and exercise capacity did not reach a level of statistical significance. After PG inhibition, plasma 13,14-dihydro-15-keto/prostaglandin F2 alpha, plasma renin, and aldosterone were reduced (P less than 0.001) at rest sitting and exercise, but PG inhibition did not prevent the exercise-induced stimulation of the plasma renin-aldosterone system. The urinary sodium excretion, averaging 156 meq/24 h during placebo, decreased (P less than 0.001) by 28 meq/24 h during PG inhibition: urinary aldosterone and kallikrein and the plasma catecholamines remained unchanged. In resting and exercising sodium-replete subjects, prostaglandins seem to exert a depressor effect on the systemic circulation and to increase plasma renin activity, but they are probably not involved in the exercise-related stimulation of the plasma renin-aldosterone system.

Adult↗
PubMed1984

Effect of indomethacin on active and inactive renin in sodium-replete men at rest and during exercise.

The effect of fatty acid cyclooxygenase inhibition by indomethacin on active renin and on acid-activable inactive renin was studied in nine healthy men with sodium repletion, at rest and during exercise. These volunteers were tested after treatment with placebo or indomethacin (150 mg daily for 3 days). During administration of indomethacin, total, active, and inactive renin levels were reduced at rest and during exercise. However, the exercise-induced stimulation of active and total renin still occurred during indomethacin administration. Indomethacin reduced (p less than 0.001), during rest sitting and at maximal exercise, the plasma concentrations of immunoreactive prostaglandin E2, prostaglandin F2 alpha, and 13,14-dihydro-15-keto-prostaglandin F2 alpha. Urinary excretion of immunoreactive prostaglandin E2 and F2 alpha was also reduced.

Adult↗
PubMed1984

Contraceptive pill use, urinary sodium and blood pressure. A population study in two Belgian towns.

The relationship between contraceptive pill use, urinary sodium and blood pressure was investigated in a random sample of the premenopausal female inhabitants of 2 small Belgian towns. Systolic and diastolic pressure tended to be higher in 58 present pill users (126 +/- 11/75 +/- 9 mm Hg: mean +/- standard deviation) than in 110 women not currently taking the contraceptive pill (123 +/- 11/74 +/- 8 mm Hg). Their urinary sodium excretion averaged 149 +/- 47 and 143 +/- 57 mEq/24 h, respectively. Systolic pressure was positively associated with 24-hour urinary sodium in pill users (r = +0.41; p less than 0.01) and in those not on the pill (r = +0.19; p less than 0.05). This association was independent of age and persisted after adjusting for body weight and pulse rate in pill users, but was no longer apparent in the others when body weight, pulse rate, and age were taken into account. Thus, pill use was associated with an elevation of arterial pressure. In subjects taking the pill a positive association was observed between the urinary sodium excretion and systolic pressure. It is therefore possible that the systolic pressure of pill users becomes responsive to their usual sodium intake.

Adult↗
PubMed1983

Long-term converting-enzyme inhibition as a guide to surgical curability of hypertension associated with renovascular disease.

Converting-enzyme inhibition as a guide to the hypotensive response to be expected from surgery was evaluated in 27 hypertensive patients with renovascular disease. Blood pressure averaged 163 +/- 5/102 +/- 2 mm Hg (mean +/- standard error of the mean) during converting-enzyme inhibition with captopril, 518 +/- 29 mg daily for 2.8 +/- 0.3 months, and stabilized at a similar level of 165 +/- 4/104 +/- 3 mm Hg during 5.0 +/- 0.6 months of postoperative follow-up, when no medication was administered. Postoperative pressure, both systolic (r = +0.53; p = 0.004) and diastolic (r = +0.55; p = 0.003), was correlated with blood pressure during converting-enzyme inhibition. In addition, multiple regression analysis identified systolic pressure during converting-enzyme inhibition as the only significant (p less than 0.01) predictor of postoperative systolic pressure. Diastolic pressure during converting-enzyme inhibition (p less than 0.05) in conjunction with circulating renin (p less than 0.05) and renin suppression from the contralateral kidney (p less than 0.01) explained up to 53% of the postoperative diastolic pressure. Therefore, blood pressure during long-term converting-enzyme inhibition may be useful as a predictor of the postoperative blood pressure in hypertensive patients with renovascular disease.

Adult↗
PubMed1983

Double-blind comparison between propranolol and bendroflumethiazide in captopril-treated resistant hypertensive patients.

In a double-blind crossover trial, 15 captopril (daily dose 600 mg) treated patients received in addition to the converting enzyme inhibitor, placebo, propranolol (240 mg), or bendroflumethiazide (7.5 mg). Propranolol produced an additional hypotensive effect, while pulse rate slowed, indicating effective beta-adrenoceptor blockade. Plasma renin activity decreased, but the hypotensive effect of propranolol was not accompanied by changes in the plasma angiotensin II and aldosterone levels or in the urinary aldosterone excretion. Also bendroflumethiazide lowered blood pressure, while body weight decreased slightly. During captopril-bendroflumethiazide treatment, serum sodium and potassium decreased while the plasma renin-angiotensin-aldosterone system was stimulated. In these captopril-treated patients, the hypotensive response to bendroflumethiazide tended to be somewhat larger than the response to propranolol, but the difference was small and statistically not significant.

Bendroflumethiazide↗
PubMed1983

Effects of tibalosine, a new alpha-adrenoceptor antagonist, in essential hypertension.

Tibalosine is a phenylethylamine derivative known to lower arterial pressure in hypertensive animal models. In a double-blind cross-over study, 12 patients with essential hypertension, on a constant sodium intake, received placebo and tibalosine, 150 mg daily. Standing (-5.5/-6.0 mm Hg) and supine (-8.5/-7.5 mm Hg) blood pressure and standing (-7.0 bmp) and supine (-7.5 bpm) pulse rate were reduced by tibalosine. Plasma renin activity (-0.41 ng/ml/hr) and plasma angiotensin 1 (-47 pg/ml) and angiotensin II (-3.0 pg/ml) levels decreased. There were no significant changes observed in plasma aldosterone or in the urinary excretion of aldosterone, kallikrein, or prostaglandin E2, F2 alpha, and F alpha metabolites. During tibalosine treatment, creatinine clearance decreased by 20 ml/min and serum creatinine rose by 0.04 mg/100 ml. The increase in serum sodium by 0.05 mmol/l was not accompanied by significant changes in body weight. There were small, but significant reductions in hemoglobin (-0.4 gm/100 ml), hematocrit (-1.5%), and erythrocyte count (-0.15 X 10(6) cells/mm3) during tibalosine intake, while blood glucose rose by 4.0 mg/100 ml. Apart from a slight tranquilizing effect in two anxious patients, no obvious sedation was observed. Subjective complaints were as frequent during placebo as during active treatment periods.

Adrenergic alpha-Antagonists↗