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Biomedical subjects

A Cattaert

Publications and source records attributed to A Cattaert.

8 recordsLinked 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

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

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↗
PubMed1983

Effects of beta 1-adrenoceptor agonism on plasma renin activity in normal men.

The contribution of beta 1-adrenoceptors to the regulation of plasma renin activity was investigated in nine healthy sodium-replete volunteers: seven subjects received a cumulative intravenous dose of 75 micrograms/kg prenalterol, a predominant beta 1-adrenoceptor agonist, and two subjects only vehiculum. In the seven actively treated subjects beta 1-adrenoceptor agonism increased (P less than 0.001) systolic intra-arterial pressure by an average of 16 +/- 4 mm Hg and heart rate by 19 +/- 3 beats min. These increases were significantly (P less than 0.04) different from the changes observed in the two control subjects (+ 3 +/- 4 mm Hg and -1 +/- 4 beats/min, respectively). Plasma renin activity, however, tended to decrease in both the actively (-38%) and saline (-28%) treated subjects. Predominant beta 1-adrenoceptor agonism, powerful enough to increase systolic pressure and heart rate does not increase plasma renin activity in supine sodium-replete normal man.

Adrenergic beta-Agonists↗
PubMed1983

Ventilatory thresholds during short- and long-term exercise.

The ventilatory (anaerobic) threshold for short-term exercise was defined as the work rate or O2 uptake (VO2) immediately below the work rate at which ventilation increased disproportionately relative to work rate or VO2, and the ventilatory threshold for long-term exercise as the work rate or VO2 immediately below the work rate at which ventilation continued to increase with time rather than attain a steady state. The purpose of the present study was to investigate how both thresholds relate to each other and how they relate to other measures of physical performance capacity. The subjects were eight healthy males, 20-53 yr of age. Maximal performance capacity was estimated by measurements of maximal O2 uptake (VO2 max) and by endurance performance during a 12-min distance run. A high interrelationship was found between the two thresholds (r = 0.84), and each threshold expressed in VO2 (ml X min-1 X kg-1) correlated highly with VO2 max (r = 0.87 and r = 0.75, for short-term and long-term exercise, respectively). When the two thresholds were expressed as a percentage of VO2 max, neither threshold showed a significant relationship with VO2 max. Endurance performance was significantly correlated with both the ventilatory threshold for short-term and long-term exercise (r = 0.73 and 0.82, respectively). A stepwise multiple regression analysis indicated that the distance run in 12 min was best predicted by VO2 max (R2 = 0.66) or the ventilatory threshold for long-term exercise (R2 = 0.63). It is concluded that the ventilatory threshold for long-term exercise is a more specific measure to explain running performance than is the threshold during graded exercise.

Adult↗
PubMed1982

Anaerobic threshold for long-term exercise and maximal exercise performance.

The anaerobic threshold during graded exercise (GXT, AT1) was determined as the exercise level initiating a curvilinear increase in ventilation (VE), and during prolonged exercise (PXT, 40 min, AT2) as the maximal exercise level where still a steady state for VE can be reached. Subjects were 8 healthy males, 20 to 53 years of age. Maximal exercise capacity was estimated by means of 1) VO2 max 2) max time on bicycle ergometer at 200 Watts and 3) maximal distance run within 12 min (Cooper test). VO2 max was significantly related to AT1, GXT (r = 0.85, 0.01 less than p less than 0.001) and to AT2, PXT (r = 0.75, 0.05 less than p less than 0.01). Also a significant correlation was found between the endurance exercise capacity (= 200 Watts) and both AT1 (r = 0.80; 0.05 less than p less than 0.01) and AT2 (r = 0.84; 0.01 less than p less than 0.001). Finally only AT2 was significantly correlated with the Cooper test (r = 0.81; 0.01 less than p less than 0.001), no significant relationship was found for AT1 (r = 0.68; p less than 0.05). In conclusion AT1 reached the highest correlation with a short maximal exercise test such as VO2 max, in contrast to AT2, which showed the highest correlation with endurance exercise such as Cooper test or maximal exercise time at 200 Watts.

Adult↗
PubMed1982

The relative effect of mental and physical activity on blood-pressure and heart rate during the waking-up process.

1. The morning rise in blood pressure and heart rate was studied in 18 patients with mild blood pressure elevation. Passing from sleep to the drowsy state raised blood pressure and heart rate very little while the awake state (reading a newspaper sitting in bed) increased the mean blood pressure by 13.2 mm Hg and the heart rate by 5.7 beats per minute. 2. Subsequent application of mental stress (arithmetic) in one third of the patients or physical activity in the upright position in another third showed a different pattern of response. Mental stress mainly raised the blood pressure while physical activity in the upright position mainly raised the heart rate.

Activity Cycles↗