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Biomedical subjects

J Staessen

Publications and source records attributed to J Staessen.

At least 163 records · Page 9Linked to original sources
PubMed1988

Obesity and hypertension.

In adults of Western societies the positive relationship between blood pressure and body weight has often been demonstrated, both cross-sectionally and longitudinally. This correlation is even stronger in children and early adulthood. In most studies in children, the association between age and blood pressure disappears after controlling for weight. Association must be differentiated from causation. It has however been shown in several intervention studies that treatment of obesity by weight loss decreases blood pressure substantially both in hypertensive and normotensive subjects. Although combining results from several intervention trials is difficult this is the only practical way to get an overall estimate of the hypotensive response to be expected from weight reduction. In the studies presently reviewed, a decrease in weight by 1 kg resulted in a reduction in blood pressure by 3.4/1.3 mm Hg in hypertensive patients and in normotensive subjects the corresponding reductions averaged 1.4 mm Hg and 0.6 mm Hg for systolic and diastolic pressure, respectively.

Animals↗
PubMed1988

Implications of the main therapeutic trials conducted in hypertension.

An impressive number of patients has been followed in intervention trials, some of them carefully designed and executed. The different intervention trials in hypertensives are compatible with the hypothesis that hypotensive drug treatment can decrease cardiovascular mortality mainly by decreasing cerebrovascular mortality. A decrease in fatal and non-fatal cardiovascular event rate is mainly due to the decrease in cerebrovascular events. On the basis of these trials the expert committee of the WHO and ISH recommend first general hygienic measures. When the blood pressure remains above 100 mm Hg after 3 months or above 95 mm Hg after 6 months follow-up, hypotensive drugs should be considered. It is not established whether the hypotensive drug treatment is advisable in: --symptomless patients with isolated systolic hypertension, --hypertensive patients above age 80. Sudden reduction in blood pressure should be avoided but whether a progressive reduction of the systolic blood pressure below 140 mm Hg and a diastolic blood pressure below 85 mm Hg is dangerous or advantageous remains to be established.

Adult↗
PubMed1987

Acute haemodynamic and humoral responses to felodipine and metoprolol in mild hypertension.

Oral administration of felodipine to 10 patients with mild essential hypertension acutely reduced systemic vascular resistance (SVR) by 40% after 30 min. The change in SVR was significantly related to age (r = -0.74). The reduction in the intraarterially measured brachial artery pressure was limited to 15/13 mmHg, due to a rise in cardiac output (CO). The tachycardia was sustained for 90 min, as was an elevation of plasma noradrenaline. There was a transient increase in stroke volume, associated with a reduction in pulmonary capillary wedge pressure, which was at least partly due to a reduced intravascular volume. In contrast to SVR, pulmonary vascular resistance was not affected by felodipine. Addition of intravascular metoprolol after 90 min decreased HR and CO and augmented SVR. The felodipine-induced rise in plasma renin activity (PRA) of 100% was completely reversed by metoprolol. Plasma angiotensin II (PA II) rose by 15% during felodipine, whereas plasma aldosterone concentration (PAC) was not affected. Thus, acutely administered felodipine was a potent dilator of systemic but not of pulmonary arterioles, it stimulated the sympathetic nervous system, and reduced left ventricular filling pressure. The rise in plasma renin did not result in a higher plasma aldosterone level, due partly to reduced generation of angiotensin II.

Adult↗
PubMed1987

Progressive attenuation of the carotid baroreflex control of blood pressure and heart rate during exercise.

With the use of a variable pressure neck chamber, the effect of supine bicycle exercise on the carotid baroreceptor reflex was investigated in 10 normal volunteers who were studied at rest and during moderate and severe exercise, i.e., at 33% and 66% of their previously determined maximal exercise capacity. Deactivation of the carotid baroreceptors by a decrease in carotid transmural pressure produced a greater (p less than 0.001) increase in mean intra-arterial pressure at rest (+11.2 +/- 0.2 [SE] mm Hg) than during moderate (+9.0 +/- 0.2 mm Hg) and severe (+6.1 +/- 0.1 mm Hg) exercise. Heart interval decreased less (p less than 0.005) at rest (-73 +/- 3.2 msec) than during exercise (-0.7 +/- 0.7 msec and -4.6 +/- 0.2 msec, respectively). Furthermore, activation of the carotid baroreceptors by an increase in carotid transmural pressure provoked a greater (p less than 0.005) reduction in mean intra-arterial pressure at rest (-11.5 +/- 0.2 mm Hg) than during exercise (-9.8 +/- 0.1 mm Hg and -7.5 +/- 0.1 mm Hg, respectively), while the lengthening of heart interval was also more (p less than 0.005) pronounced at rest (+97 +/- 4.3 msec) than during moderate (+44 +/- 1.2 msec) and severe (+7.6 +/- 0.3 msec) exercise. Finally, carotid baroreceptor sensitivity was defined as the slope of the changes in blood pressure and heart interval that occurred with increasing (baroreceptor deactivation) and decreasing (activation) neck tissue pressure. On average, baroreceptor sensitivity was consistently smaller (p less than 0.05) during exercise, as compared to rest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Calcium entry blockade or beta-blockade in long-term management of hypertension in blacks.

The long-term efficacy of nitrendipine and acebutolol was assessed during a 40-week double-blind randomized trial in 60 hypertensive blacks. Nitrendipine (mean dose 32 mg/day) and acebutolol (414 mg/day) were administered in monotherapy in increasing dosage and mefruside was added in patients not controlled by monotherapy. The recumbent and standing blood pressures were reduced (P less than 0.01 or less) during monotherapy with nitrendipine and acebutolol, but the magnitude of blood pressure reduction was greater (P less than 0.05 or less) during nitrendipine dosing. Pulse rate decreased (P less than 0.01) during acebutolol whereas nitrendipine induced a nonsignificant increase. Both treatments induced no changes in serum electrolytes, creatinine, urea, uric acid, lipids, plasma renin activity, and plasma and urinary aldosterone. The overall incidence of side effects was similar with both treatments but four patients discontinued nitrendipine because of headache. The addition of mefruside to nitrendipine or acebutolol produced a further fall of blood pressure in patients not controlled with monotherapy. Monotherapy with nitrendipine or acebutolol offers an effective, safe first-line antihypertensive treatment in blacks entered in this study; with the described dosages and therapeutic schedule, nitrendipine was somewhat more effective than acebutolol.

Acebutolol↗
PubMed1987

Noninvasive assessment of systolic and diastolic left ventricular function in female runners.

Nine female runners and 9 matched control subjects were investigated with echocardiography and Doppler velocimetry to assess cardiac structure and systolic and diastolic left ventricular (LV) function at rest. LV mass was considerably larger in the athletes (171 vs 123 g; P less than 0.01). Minute distance, the Doppler index of cardiac output, was similar in runners and controls; the lower heart rate (P less than 0.01) of the athletes was associated with a higher stroke distance (P less than 0.05). The latter could be attributed to a larger end-diastolic LV internal diameter (46 vs 43 mm; P less than 0.05); wall stress and the various indices of systolic LV function were not different between runners and controls. Early diastolic LV function, estimated from the velocity of LV relaxation and the LV inflow pattern, and late diastolic function, assessed by Doppler velocimetry, were similar in runners and controls. The unchanged ratio of the peak velocities of LV filling during atrial contraction and early filling (0.49 vs 0.44; NS) indicates that LV distensibility is unaltered in the athletes. In conclusion, the higher left ventricular mass of female runners is not associated with changes of systolic and diastolic LV function.

Cardiac Volume↗
PubMed1987

Mechanism of hypotensive action of ketanserin in men.

The mechanism of the hypotensive action produced by ketanserin during chronic treatment in humans remains unknown. In contrast to previous reports, recent data show that ex vivo inhibition of the serotonin-induced platelet aggregation can be demonstrated in men during chronic ketanserin administration, provided that the pH is controlled in the in vitro assay. This test could be used as a tool to measure the degree of serotonin inhibition, at least at the platelet level.

Antihypertensive Agents↗
PubMed1987

The use of Doppler echocardiography to assess the acute haemodynamic response to felodipine and metoprolol in hypertensive patients.

In order to evaluate the use of Doppler echocardiography in the assessment of the haemodynamic effects of antihypertensive drugs, the acute haemodynamic response to felodipine and additional administration of metoprolol after 90 min was assessed in 10 hypertensive patients, by using both the Fick method and Doppler blood flow velocimetry in the ascending aorta. Intrabrachial artery pressure was significantly reduced by the treatment. Both the Fick and Doppler estimates of cardiac output (CO) rose significantly with felodipine and reached their highest values after 30 min, 45 +/- 8% (s.e.m.) and 58 +/- 7%, respectively. The felodipine-induced increase of heart rate (HR) persisted for 90 min, but the increase of stroke volume was only transient. Metoprolol brought CO and HR back to control levels. The felodipine- and metoprolol-induced changes of CO and stroke volume (SV) from control were on average not different between the observations with the Fick and the Doppler techniques throughout the study. As for the absolute values (control period), the Doppler measurement under-estimated SV (10 ml) and CO (1.1 l/min) in comparison with the Fick method, and the limits of agreement (mean difference +/- 2 s.d.) between both methods were 42 and -22 ml for stroke volume and 3.4 and -1.2 l/min for CO. In conclusion, despite the poor agreement in absolute results between the two methods, aortic Doppler velocimetry reflects the acute haemodynamic changes induced by felodipine and metoprolol in a group of hypertensive patients. The technique should facilitate the study of haemodynamic effects of drugs in man.

Adult↗
PubMed1987

Correlates of blood pressure in rural and urban Zaïre.

Blood pressure and anthropometric characteristics were studied in 312 rural and 675 urban Bantu of Zaïre aged 10 years and more; proteinuria and the urinary sodium to potassium ratio were determined. On average, systolic and diastolic pressure were higher in rural than in urban Bantu, and rose with advancing age in both populations. However, rural Bantu were older, lighter and smaller, and had a lower sodium:potassium ratio than urban Bantu. Using multiple regression analysis, systolic and diastolic pressures correlated positively with age, weight, pulse rate, sex and sodium:potassium ratio; diastolic pressure also correlated negatively to height. After adjusting blood pressure for these independent correlates, systolic pressure remained significantly higher in rural Bantu. However, no significant difference persisted between the two populations after adjusting blood pressure for age alone. The prevalence of hypertension in rural and urban Bantu increased with age and was 14.2 and 9.9%, respectively, for participants at least 20 years old; women were more affected in the rural area, whereas men were more affected in the urban population. The occurrence of proteinuria was higher in rural Bantu than in urban; it was similar in participants with and without definite hypertension. It is suggested that higher blood pressure in the rural setting was mostly accounted for by the older age of the population.

Adolescent↗
PubMed1987

Serum cholesterol during ketanserin and propranolol administration in hypertensive patients.

The effect of ketanserin and propranolol on the serum total cholesterol (TC), and high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) cholesterol was studied in hypertensive patients treated for 3 months. During ketanserin administration, LDL-C decreased, whereas HDL-C and the HDL-C/LDL-C ratio increased and no significant effect in serum total cholesterol occurred. During propranolol administration, no significant effect was observed on serum total cholesterol, HDL-C and LDL-C, but the ratio of HDL-C/LDL-C increased. Intergroup comparison showed a greater increase in HDL-C (p less than 0.05) and in the HDL-C/LDL-C ratio (p less than 0.01) in the ketanserin group as compared with the propranolol group.

Body Weight↗
PubMed1987

Plasma renin system during exercise in normal men.

The exercise-related increase in plasma renin activity (PRA) and in the plasma concentration of angiotensin II (ANG II) and aldosterone (Aldo) was studied in 43 healthy volunteers whose 24-h urinary sodium excretion (UVNa) ranged from 10 to 250 mmol. Arterial blood samples were obtained at rest and during bicycle ergometry. Compared with rest, PRA, ANG II, and Aldo rose to a similar extent during light and moderate exercise. However, at peak exercise ANG II increased significantly more (P less than 0.001) than PRA and Aldo. Thus, with increasing intensity of exercise, the slope of the linear regression of ANG II on PRA became significantly (P less than 0.001) steeper, whereas at maximal exercise the Aldo response did not follow the acute rise in ANG II. At rest as well as during exercise, Aldo rose with increasing ANG II, but the stimulatory effect of ANG II on Aldo was attenuated with higher sodium intake, as estimated from UVNa. Finally, independent of the level of physical activity, UVNa was negatively correlated with PRA, ANG II, and Aldo.

Adult↗
PubMed1987

Effects of felodipine and metoprolol on blood pressure, plasma renin, angiotensin II, aldosterone and catecholamines in hypertensive patients.

Oral administration of felodipine to 10 patients with mild essential hypertension acutely reduced the brachial artery pressure by 15/13mm Hg. The tachycardia which occurred was sustained for 90 minutes together with an elevated plasma noradrenaline concentration. Addition of intravascular metoprolol after 90 minutes decreased heart rate. The felodipine-induced increase of plasma renin activity (100%; p less than 0.001) was completely reversed by metoprolol. Plasma angiotensin II (PA II) rose by 15% (p less than 0.05) during felodipine, whereas plasma aldosterone concentration was not significantly affected.

Adult↗
PubMed1987

Effects of felodipine on blood pressure and humoral factors in sodium-replete humans at rest and during exercise.

The effect of short-term calcium antagonism with felodipine on blood pressure and on plasma catecholamines, renin, and aldosterone was studied in 10 normal volunteers at rest and during incremental bicycle exercise. At rest, diastolic blood pressure was slightly increased during felodipine treatment, whereas systolic pressure and heart rate were not significantly changed. The plasma noradrenaline concentration and plasma renin activity were increased during felodipine treatment; the plasma adrenaline and aldosterone concentrations, on the contrary, were not significantly changed. The rises in plasma renin activity, plasma aldosterone, and plasma adrenaline and noradrenaline concentrations produced by exercise were not significantly affected by felodipine. It is concluded that the rise in plasma renin activity during calcium antagonism with felodipine is not accompanied by a significant increase in plasma aldosterone. Furthermore, the present data suggest that, at least during exercise, calcium antagonism does not interfere with the mechanisms underlying the exercise-induced activation of renin and aldosterone release.

Adult↗
PubMed1987

Plasma levels of alpha-atrial natriuretic peptide in normal subjects under various postural conditions.

The present paper describes a radioimmunoassay, in conjunction with an extraction procedure on octadecasilyl silica cartridges, of alpha-atrial natriuretic peptide in human plasma and its application in normal subjects under various postural conditions. The sensitivity of this assay is 1.96 pg/ml. The plasma concentrations of alpha-atrial natriuretic peptide in 18 normal male subjects ranged from 10 to 55 pg/ml. This assay was shown to be reproducible as indicated by the low within- and between-assay coefficients of variation. The plasma alpha-ANP concentration decreased during prolonged storage of the plasma at -20 degrees C or -80 degrees C and its level is also lower in hemolyzed plasma samples. The plasma alpha-ANP concentration is similar in standing and supine position but rose significantly when the subjects were tilted 20 degrees head-down.

Aldosterone↗
PubMed1987

ACE-inhibitors in the treatment of elderly hypertensives.

Angiotensin-converting enzyme inhibitors are gaining acceptance as safe and effective agents for treatment of hypertension. Data on their use specifically in elderly hypertensives, however, are limited. Addressed in this review of the available literature are the questions whether they are effective hypotensives in the elderly, whether their effects are age-related, and what effects, if any, do they have on morbidity and mortality in geriatric hypertension.

Aged↗
PubMed1987

Dietary sodium variation, erythrocyte cationic transport and plasma renin-aldosterone in men.

Erythrocyte concentrations and fluxes of sodium and potassium were investigated in normal white male subjects during dietary sodium restriction and repletion, each period lasting for 16 weeks. Intraerythrocyte sodium concentration decreased and red cell ouabain-sensitive 86Rubidium-uptake increased during dietary sodium restriction while no significant changes were observed in the total, furosemide-resistant and furosemide-sensitive sodium-efflux and the sodium, lithium-countertransport. The decrease in intraerythrocyte sodium concentration could have resulted from the observed increase in sodium, potassium-ATPase pump activity. The latter increase could have been secondary to the early decrease in a digitalis-like plasma inhibitor and the later increase could have been facilitated by the late rise in the intracellular adenosine triphosphate concentration, which is the energy supplier for this pump. During the subsequent first month of sodium repletion intraerythrocyte sodium concentration remained low. Red cell ouabain-sensitive 86Rubidium-uptake and adenosine triphosphate concentration remained elevated and returned to baseline only after 16 weeks. This long-term effect suggests either the involvement of a mechanism which can only be slowly reversible or a mechanism which is irreversible so that normalization takes place only when new red cells are released into the circulation.

Adult↗