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Biomedical subjects

R Fagard

Publications and source records attributed to R Fagard.

At least 379 records · Page 21Linked to original sources
PubMed1984

Influence of beta-adrenergic blockade on the hemodynamic effects of physical training in patients with ischemic heart disease.

Beta-blocking agents are widely used in the treatment of patients with coronary artery disease. Their negative chronotropic and inotropic actions may alter the effects of physical training in cardiac rehabilitation programs. Therefore, resting and exercise cardiac output, stroke volume, heart rate, and arteriovenous oxygen content difference were measured before and after training in 15 male patients with coronary artery disease, who were treated with beta blockers, and in a control group of 14 patients not treated with beta-blocking agents. At the end of a 3-month training period, oxygen uptake at peak exercise increased similarly in the two groups, 37% and 34%, respectively; this was related to increases in stroke volume and heart rate, and therefore cardiac output, and to increases in arteriovenous oxygen content difference. The effects were similar whether or not the patients were treated with beta blockers. Also, at rest and submaximal exercise, beta blockade did not affect the training-induced changes of cardiac output, heart rate, and arteriovenous oxygen content difference. In both groups heart rate decreased with training while stroke volume and cardiac output increased significantly. In conclusion, beta blockade did not significantly alter the hemodynamic effects of training.

Adrenergic beta-Antagonists↗
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

The effects of beta blockers on exercise capacity and on training response in elderly subjects.

Treatment of 8 hypertensive elderly subjects with atenolol or with labetalol did not affect exercise performance, except after the development of circulatory congestion in 1 patient. Treatment with beta blockers did not alter the response to an exercise training programme in 15 elderly patients with ischaemic heart disease, as compared with 11 patients without such treatment.

Aged↗
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

Changes in systolic time intervals during physical training in patients with ischemic heart disease. Effect of beta-blockade.

Systolic time intervals (STI) were measured at rest before and after an exercise training programme in 37 patients with ischemic heart disease; 17 patients were treated with a beta-blocking drug (BB-group) and 20 were not (nBB-group). After the training period peak oxygen uptake had increased by 37% in the BB-patients and by 41% in the nBB-group. During the training period electromechanical systole (QS2) and pre-ejection period (PEP), when corrected for heart rate, shortened significantly in all 37 patients. Left ventricular ejection time (LVET) increased but when corrected for heart rate no significant changes occurred. The ratio of PEP/LVET decreased significantly. The changes in STI were similar in the patients treated with beta-blocking drugs than in those without such treatment. The changes in STI in both groups suggest that left ventricular function improves during the training period and that beta-adrenergic blockade does not alter this outcome.

Adrenergic beta-Antagonists↗
PubMed1984

Prenalterol in the treatment of orthostatic hypotension in Shy-Drager syndrome.

The effects of prenalterol, a selective beta 1-adrenoreceptor agonist, were studied in a patient with the Shy-Drager syndrome, presenting with incapacitating orthostatic hypotension. The main haemodynamic defect was an impressive postural fall in stroke volume and cardiac output pointing to denervation of the capacitance vessels. Prenalterol 4 X 30 mg orally produced a marked increase in supine and standing blood pressure, along with substantial symptomatic improvement. Notable positive chronotropic and inotropic effects were observed. Association of fludrocortisone 0.5 mg/day resulted in further haemodynamic and symptomatic improvement, presumably due to plasma volume expansion. Haemodynamically, prenalterol and fludrocortisone resulted in a substantial increase in standing cardiac output, primarily due to the chronotropic effects of prenalterol. In addition to the haemodynamic effects, prenalterol stimulated the renin-aldosterone system and restored the normal diurnal pattern of water and sodium excretion, the latter may have contributed to the improvement of orthostatic tolerance. Prenalterol could be a valuable adjunct to the existing treatment schedules of neurogenic orthostatic hypotension.

Adrenergic beta-Agonists↗
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

Tyrosine phosphorylation in human T lymphoma cells.

A high level of tyrosine protein kinase (TPK) has been recently detected in the murine lymphoma LSTRA. The main substrate for tyrosine phosphorylation in this cell line is a Mr 55 000 protein associated with the insoluble matrix of the cell. These findings prompted the search for TPK activities in human lymphoid cells. Three human T lymphoma cell lines (i.e. Molt. 4, JM, and Ke 37) and control lymphocytes were examined. After in vitro phosphorylation of detergent insoluble extracts from human T lymphoma cells, 2 major phosphotyrosine containing proteins with Mr 55 000 and 35 000 can be detected in all three T lymphoma lines, whereas an additional species with Mr 78 000 is present only in the Ke 37 cell line. Similar size proteins are weakly phosphorylated in normal lymphocytes. Tyrosine phosphorylation in these proteins proceeds actively at 0 degrees C, and is dramatically stimulated by Mn++ ions. Partial proteolysis mappings of the Mr 55 000 phosphoproteins from murine and human lymphomas revealed a strong homology among these molecules. The function of this protein in transformed lymphocytes is discussed.

Animals↗