Intraerythrocyte sodium concentration in black families with and without hypertension.

Blood pressure and intraerythrocyte sodium and potassium concentration were investigated in 59 male inhabitants of an urban quarter of Kinshasa, aged 10 years and older. Two subjects were excluded because they were on antihypertensive treatment. Seventeen subjects were normotensive with both parents normotensive (group 1); 9 subjects were normotensive with at least one hypertensive parent (group 2); 5 subjects were untreated hypertensives (group 3) and 26 subjects could not be classified (group 4).

Cationic concentrations and transmembrane fluxes in erythrocytes of humans during exercise.

The effect of exercise on the intraerythrocyte cationic concentrations and transmembrane fluxes such as the Na+-K+-adenosinetriphosphatase (ATPase) pump, the Na+-K+ cotransport, and the Na+-Li+ countertransport system was studied in 11 normal male volunteers. All subjects performed an uninterrupted incremental exercise test on a bicycle ergometer, starting at an initial work load of 20% of the subjects' maximal exercise capacity, as determined in a pretest. The work rate was increased with an additional 20% each 6 min up to a final work load of 80%.

[Physiologic variability of erythrocyte concentrations and transport of sodium and potassium].

Sodium concentrations in erythrocytes are lower in women during the luteal phase of the menstrual cycle than in women studied during the follicular phase and in men. Sodium cotransport activity is lower in women during the follicular phase than in men. Women taking oral contraceptives show no monthly variations in erythrocyte sodium concentrations.

Erythrocyte 2,3-diphosphoglycerate and serum enzyme concentrations in trained and sedentary men.

The acute effect of exercise on the intraerythrocyte 2,3-diphosphoglycerate concentration and on various serum enzymes and some related variables was investigated in 14 male athletes before and after a 50-min cross-country run and compared at rest to 15 sedentary subjects. Compared to the sedentary subjects, the athletes had higher resting levels of serum creatine phosphokinase, plasma myoglobin, and renin substrate but had a lower plasma renin activity. The red blood cell 2,3-diphosphoglycerate concentration increased after exercise in the runners and was not different at rest between the athletes and the sedentary subjects.

Differentiation of exercise-induced metabolic responses during selective beta 1- and beta 2-antagonism.

The effect of beta 1- or beta 2-antagonism on the plasma levels of glucose, lactate, triglycerides, and free fatty acids was studied in seventeen normal male volunteers. All subjects performed three graded and uninterrupted exercise tests until exhaustion. Prior to each exercise test they received in a randomized order during three consecutive days either placebo or a predominant beta 1-blocker (atenolol, 50 mg once per day) or a predominant beta 2-blocker (ICI 118,551, 20 mg t.

Impairment of renal function due to sulphinpyrazone after coronary artery bypass surgery: a prospective double-blind study.

In this randomized, double-blind, placebo-controlled trial the renal function was studied in 60 patients recovering from coronary artery bypass surgery treated with a daily dose of 800 mg sulphinpyrazone (SP) or 880 mg acetylsalicylic acid (ASA) or placebo. Serum creatinine level increased (p less than 0.05) during the first 2 days of SP treatment, but returned to its baseline level within 4 days under maintained therapy; during ASA and placebo therapy no significant changes occurred.

Ventilatory threshold measurement to evaluate maximal endurance performance.

The ventilatory (anaerobic) threshold during short-term exercise has been defined as the O2 uptake (VO2) immediately below the VO2 at which pulmonary ventilation (VE) increases disproportionally relative to VO2 and the ventilatory threshold for long-term exercise as the VO2 immediately below the VO2 at which the VE continues to increase with time rather than attain a steady state. Maximal endurance performance was determined by measurement of the maximal endurance time during treadmill runs at 90%, and 70% of the previously determined VO2 max. The purpose of the present study was to investigate how maximal endurance performance was related to both ventilatory thresholds and to VO2max, and to select which variable best explained maximal endurance performance.

Sodium and potassium fluxes and concentrations in erythrocytes of normal subjects during prolonged sodium depletion and repletion.

The erythrocyte concentration 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. During dietary sodium restriction the intra-erythrocyte sodium concentration decreased and the red cell ouabain-sensitive 86Rb-uptake increased; no significant changes were observed in the ouabain-insensitive fluxes of sodium such as the total, frusemide-resistant and frusemide-sensitive Na+-efflux and the Na+, Li+-countertransport. The decrease in the intra-erythrocyte sodium concentration could result from an increased Na+,K+-ATPase pump activity.

Chronic treatment with tibalosine in essential hypertension.

Unlabelled: After a run-in period on placebo, 26 patients with essential hypertension were prescribed single-blind tibalosine, 150 mg daily. On tibalosine their blood pressure decreased from 157/101 to 147/93 mm Hg (p less than 0.001) and their heart rate from 74 to 68 beats per minute (p less than 0.

Beta-adrenoceptors and the regulation of blood pressure and plasma renin during exercise.

The relative role of beta 1- and beta 2-adrenoceptors in the regulation of blood pressure and plasma renin at rest and during exercise was studied in 17 normal male volunteers. They performed, in a randomized order and according to a double-blind crossover study design, three graded and uninterrupted exercise tests until exhaustion after being pretreated during 3 consecutive days with a placebo, with a predominantly beta 1-blocker (atenolol, 50 mg once/day), or with a predominantly beta 2-blocker (ICI 118551, 20 mg 3 times/day). Both drugs caused a decrease of heart rate, but the reduction by ICI 118551 was less pronounced at rest and no additional decline occurred at exercise.

Relative potency of a beta-blocking and a calcium entry blocking agent as antihypertensive drugs in black patients.

The short-term efficacy of nitrendipine (N) as a first stage antihypertensive drug in black patients has been assessed and compared with acebutolol (A) in a double-blind study. Forty patients were randomized and after a 4 week run-in period on placebo, the active treatment was administered for 6 weeks starting with 20 mg N or 200 mg A once daily. The dose was increased up to 60 mg N or 600 mg A as needed.

Erythrocyte cations and Na+,K+-ATPase pump activity in athletes and sedentary subjects.

The chronic effect of training on intraerythrocyte cationic concentrations and on red cell Na+,K+-ATPase pump activity was studied by comparing well-trained athletes with sedentary subjects at rest. Also the acute effect of a 50-min cross-country run on these erythrocyte measurements was studied in the athletes. At rest the intraerythrocyte potassium concentration was increased (P less than 0.

Influence of hypotensive drug treatment in elderly hypertensives: study terminating events in the trial of the European Working Party on High Blood Pressure in the Elderly.

The European Working Party on High Blood Pressure in the Elderly (EWPHE) trial was a double-blind randomized placebo-controlled trial of antihypertensive treatment in patients over the age of 60 years. Entry criteria included both a sitting diastolic blood pressure on placebo treatment in the range 90-119 mmHg and a systolic blood pressure in the range of 160-239 mmHg. The patients (n = 840) were randomized either to active treatment (hydrochlorothiazide + triamterene) or matching placebo.

Relationship between carotid baroreflex sensitivity, physical fitness and activity in cyclists.

Carotid baroreceptors were stimulated with neck suction in 24 cycling tourists and pulse interval lengthening was measured. Eight intensities of neck chamber suction were applied to select a criterion for computing the RR response that gives a significant linear relationship with the magnitude of the stimuli in the highest number of individuals. The best criterion was the maximal RR prolongation within 5 s after the onset of the stimulus.

The nature of opioid involvement in the hemodynamic respiratory and humoral responses to exercise.

After 30 min rest in the lying position, 12 healthy male volunteers (average age 22 years) received, in a randomized double-blind cross-over protocol, either saline or naloxone (10 mg iv followed by a continuous infusion of 10 mg/hr). Thereafter they rested for a further 30 min in the recumbent position and for 15 min sitting on a bicycle ergometer; they then exercised to exhaustion. At rest plasma levels of adrenocorticotropin (ACTH), cortisol, and aldosterone increased during infusion of naloxone, while body temperature decreased.

Differential responses of plasma aldosterone, cortisol and adrenocorticotropin to two dopamine receptor antagonists.

The response of plasma aldosterone, cortisol and adrenocorticotropin (ACTH) to the dopamine antagonists metoclopramide and domperidone, administered intravenously in a dose of 1 mg/kg, was investigated in healthy volunteers. Within 15 min after metoclopramide administration, plasma aldosterone (+ 99%), cortisol (+ 75%) and ACTH (+ 55%) increased (p less than 0.001), whereas the plasma levels of these hormones were not altered after domperidone.

Plasma levels of renin, angiotensin II, and 6-ketoprostaglandin F1 alpha in endurance athletes.

Twelve male runners and 12 matched nonathletes performed a prolonged uninterrupted graded exercise test on the bicycle ergometer up to exhaustion to study blood pressure and plasma levels of renin (PRA), vasoconstrictor angiotensin II (ANG II), and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha), a metabolite of the vasodilator prostacyclin. In the athletes work load was increased by 30 W/4 min, and in the control subjects the increments of work load were adjusted to their lower exercise capacity to equalize total exercise duration. Blood was drawn, and blood pressure and O2 uptake (VO2) were measured at rest and at the fourth, eighth, and last steps of exercise.

Intra-erythrocyte concentration and transmembrane fluxes of sodium and potassium during acute and short-term administration of ketanserin in normal male subjects.

The effect of acute and short-term administration of ketanserin on the intracellular concentration and transmembrane fluxes of sodium and potassium in erythrocytes was studied in 12 sodium-replete, normal male subjects. The subjects received 40 mg ketanserin three times a day for one week. Blood samples were drawn before and 2.

In vitro inhibition of renal sodium-potassium ATPase activity by progesterone.

The effect of various steroids and prostaglandins on the activity of canine kidney Na+, K+-ATPase activity was tested in vitro. Progesterone induced a dose-dependent increase in inhibition of the canine kidney Na+, K+-ATPase activity. Aldosterone, cortisol, cortisone as well as prostaglandin E2 and 13,14-dihydro-15-keto-prostaglandin F2 alpha, did not cause an inhibition of canine kidney Na+, K+-ATPase.

Mortality and morbidity results from the European Working Party on High Blood Pressure in the Elderly trial.

A double-blind randomised placebo-controlled trial of antihypertensive treatment was conducted in patients over the age of 60. Entry criteria included both a sitting diastolic blood pressure on placebo treatment in the range 90-119 mm Hg and a systolic pressure in the range 160-239 mm Hg. 840 patients were randomised either to active treatment (hydrochlorothiazide + triamterene) or to matching placebo.

Active and acid-activable inactive renin during inhibition by indomethacin of prostaglandin synthesis in sodium-replete man.

The effect of inhibition of prostaglandin synthesis by indomethacin on active renin and on acid-activable inactive renin was studied in nine healthy, sodium-replete men, both at rest and exercise. These volunteers were investigated after pretreatment with placebo or indomethacin, 150 mg daily for 3 days. Indomethacin induced a decrease in active (P = 0.

Erythrocyte concentrations and transmembrane fluxes of sodium and potassium and biochemical measurements during the menstrual cycle in normal women.

The erythrocyte concentrations and the transmembrane fluxes of sodium and potassium were investigated in 20 normal women during the two stages of the menstrual cycle. Half of the women were using oral contraceptives and the other half were not. In women with a normal menstrual cycle the erythrocyte sodium concentration and the ouabain-insensitive total potassium efflux were lower in the luteal than in the follicular phase.