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Biomedical subjects

G Dumoulin

Publications and source records attributed to G Dumoulin.

At least 37 records · Page 2Linked to original sources
PubMed1987

Relative effects of the supine posture and of immersion on the renin aldosterone system at rest and during exercise.

The relative influences of the supine posture and of immersion on the renin-aldosterone system (RAS) were studied at rest and during moderate exercise in five healthy men. When supine, resting or immersion to the neck for 20 min in a thermoneutral environment both induced a decrease in plasma renin activity (PRA) when compared with the levels measured after 15 min sitting at rest (resting: -44%, p less than 0.05. Immersion: -45%, p less than 0.05). There was no significant difference in PRA decrease between the two situations. Aldosterone (ALDO) values were lower after supine rest or immersion than those observed after sitting at rest, but the difference was not significant. Two types of exercise at a constant relative work load (40-50% maximal oxygen uptake), namely cycling on an ergocycle in the supine position and free-style swimming, induced increases in PRA and ALDO when compared with the levels measured after 15 min rest when sitting (respectively, PRA = +35%, p less than 0.05, and +45%, p less than 0.05, ALDO = +32%, p less than 0.01 and +35%, p less than 0.05). Increases in PRA and ALDO did not differ between the two exercises. Thus inhibitory effects on RAS of change in external pressure are negligible during water immersion to the neck in the supine position and during swimming at moderate intensity.

Adult↗
PubMed1987

[Radioimmunological assay of plasma arginine-vasopressin in man. Comparison of 2 methods of extraction].

Two methods of extraction, prior to radio-immunoassay (RIA) of human plasma arginine vasopressin (AVP) were tested: ethanol extraction (ETH), chromatography with ODS-Silica (ODS-Sil). Recovery of 125I AVP was higher when using ODS-Sil than when using ETH. Recovery of standard AVP and plasma enriched with standard AVP was found to be more efficient and reproducible for ODS-Sil. However, the RIA used, performed after chromatography with ODS-Sil, is not enough sensitive to detect low concentrations but is able to detect high concentrations and physiological variations of plasma AVP.

Arginine Vasopressin↗
PubMed1986

Plasma renin and aldosterone changes during twenty minutes' moderate exercise. Influence of posture.

The influence of posture on plasma renin and aldosterone changes during exercise performed at a constant relative work load (40%-50% maximal oxygen uptake) was studied in eight healthy men. Each subject carried out two 20-min exercises on an ergocycle at an interval of 8 days; the first exercise was performed in the normal sitting position (upright exercise), the second in a comfortable supine position (supine exercise). In both cases, heart rate and blood pressure were measured as well as plasma renin activity (PRA), aldosterone (ALDO) and osmolality, before and immediately after exercise, and 15 min following the end of exercise. An increase in heart rate, blood pressure, PRA, ALDO and osmolality was noted at the end of each exercise. This increase was greater in the supine exercise than when upright for PRA and ALDO; plasma osmolality and blood pressure showed identical increases for both types of exercise; increase in heart rate was greater when supine than when upright. PRA and ALDO were still elevated 15 min after the upright activity, but had regained their base values in that time after the supine exercise. Our results show that moderate, relatively brief periods of exercise stimulate the production of renin and aldosterone, but the response is less when supine than in the normal upright position.

Adult↗
PubMed1984

Expression of plasma renin activity in terms of urinary sodium excretion and posture in normal subjects on free sodium intake.

Supine and upright plasma renin activities (PRA) were measured in 151 normal subjects on free sodium intake. Supine and upright plasma renin activities were then related to the 24-hour urinary sodium or the 2-hour urinary sodium excretion, measured in the morning after overnight fasting. Urinary sodium excretion was expressed as the urinary rate per hour or as the urinary Na/creatinine ratio. Correlations were found between both supine and upright PRA and 2 h urinary sodium excretion expressed as the Na/creatinine ratio. Supine and upright PRA values are expressed in terms of these correlations with confidence intervals.

Adult↗
PubMed1984

[Variations in circulating levels of prolactin and growth hormone during physical exercise in man: influence of the intensity of the workout].

In trained subjects, circulating PRL and GH increase significantly after a 20 minutes exercise on ergometer bicycle performed either at submaximal or maximal intensity. The magnitude of PRL response appeared to be similar for both kinds of exercise, but the increase in GH level is higher after maximal exercise than after submaximal one.

Adolescent↗
PubMed1984

[Relations between oral glucose load and urinary elimination of calcium and phosphorus in healthy men with normal body weight].

Serum and urinary glucose, creatinine, calcium and phosphorus, serum insulin were measured every 60 min from 9.00 to 12.00 in twenty healthy subjects. All subjects presented normal body weight, renal function, serum glucose, serum and urinary calcium. Urinary calcium and phosphorus were expressed by Ca/creat and P/creat ratio, and renal phosphate threshold was expressed by the TmP/GFR ratio. At 9.00, after an overnight fast, ten subjects received 75 g of glucose (groupe B) and ten subjects were conserved as controls (group A). Hyperglycemia and hyperinsulinemia due to glucose load (B) induce a decrease of serum phosphorus (10.00, 11.00, 12.00), while phosphoremia increased in group A. Urinary P/creat increased in group A (12.00), and decreased in group B (12.00); while TmP/GFR decreased in group B (10.00, 11.00). Serum calcium rose in the two groups, according to the circadian rythm and urinary Ca/creat ratio increased in group A (10.00) and increased considerably in group B (10.00, 11.00, 12.00). In group B, a negative linear correlation was found between serum glucose and TmP/GFR ratio (= -0,50) and between serum phosphorus and urinary Ca/creat ratio (r = -0,40). These results show that in healthy subjects, with normal body weight, oral glucose load induced a decrease of phosphaturia and an increase of calciuria, subsequent to hyperglycemia.

Adolescent↗
PubMed1984

[Comparative study of urinary calcium, oxalate and uric acid in calcium oxalate lithiasis].

The purpose of this study was to determine and to compare the frequency of hypercalciuria, hyperoxaluria and hyperuricosuria in 49 patients with a pure or mixed calcium oxalate urolithiasis. During this study, all patients were on a normal diet and had no special disease or medication. We noted that hypercalciuria (35%) and hyperoxaluria (24%) were more often associated (18%) than isolated (8 and 2%). They were more frequent in mixed stones (44% et 39%) than in pure one (29% and 16%). Hyperuricuria (39%) had a same frequency wathever the renal stone type may be. A same frequency was noted when hyperuricuria was associated with hypercalciuria and hyperoxaluria (12%) or isolated (14%). None of these three biologic disturbances was observed in 45% of our patients.

Adult↗
PubMed1982

[Relations between the renin-angiotensin-aldosterone system and urinary elimination of sodium: study of healthy subjects in clinostatism and on a sodium-free diet].

In 94 normotensive subjects and free sodium diet, the relationship between SPRA and the 2-hour urinary sodium excretion was significantly better fitted by an hyperbolic function (p less than 0,001); r = 0,53) than a linear one (p less than 0,001; r = -0,31) between SPRA and the 24-hour urinary sodium excretion. (SPRA = Supine Plasma Renin Activity).

Adolescent↗
PubMed1982

[Urinary excretion of calcium and cyclic adenosine monophosphate in children. Comparison between the two variables].

The urinary excretion of calcium (mg/g creatinine) and cyclic adenosine 3'5' monophosphate (cyclic AMP) (mumol/g creatinine) was determined in 79 healthy children aged 2 to 12 years. An ag--related pattern to the urinary excretion of calcium was not seen. But urinary cyclic AMP levels are inversely correlated with age (r = -0,66; p less than 0,01) and there is a significant correlation between urinary calcium and cAMP levels (r = 0,2; p less than 0,05).

Aging↗
PubMed1982

[Effect of obesity on the elevation of renal glucose threshold. Studies during oral glucose tolerance tests (author's transl)].

To estimate the renal glucose threshold, we measured glucosuria in 546 oral glucose tolerance tests (OGTT) (glucose oxidase method). The subjects, with normal renal function, presented during OGTT one or several peak plasma glucose levels between 10 and 13.4 mmol/l. The renal glucose threshold was thus higher than 10 mmol/l in the 43% of this population who were a glucosuric (normal renal threshold was between 8.8 and 10 mmol/l). The frequency of raised threshold was higher in obese patients than in subjects of normal body weight: indeed from 34% in non obese patients rates rose respectively at 37%, 50% and 68% in obesity groups (10 to 30%, 30 to 50% and 50% over ideal body weight (respectively). This trend was found regardless of the type of glucose tolerance response (ie. normal, IGT, non diagnostic, NIDD).

Blood Glucose↗
PubMed1982

[Changes in plasma prolactin levels during physical exercise in man: effect of preliminary mental activity related to emotional stress].

1. Eighteen male volunteers, from 19 to 21 years, were studied immediately before and after submaximal exercise (50-70% VO2 max and from 0.30 to 0.50 p.m.). These subjects accomplished from 10 to 11:30 a.m. two kinds of mental work: group A (n = 10) was attending a lecture and group B (n = 8) was sitting for an examination (i.e. mental work associated with emotional stress). 2. Plasma prolactin levels were measured before and after exercise by radioimmunoassay method. Results were compared between these two groups and with control groups C (n = 6) and D (n = 6), at rest from 0.30 to 0.50 p.m., and respectively placed in the same situations as groups A and B prior exercise. 3. Plasma prolactin rose during exercise following mental work as generally observed in exercise. On the contrary plasma prolactin decreased during exercise following an examination but prolactin levels before exercise were significantly higher if stress was prior to exercise. This marked increment in plasma prolactin could be related to stress associated with examination if compared to control groups; the previous emotional stress could inhibit prolactin response to a future excitement.

Adult↗
PubMed1981

[The effect of an intravenous calcium load on plasma prolactin in man (author's transl)].

Eighteen male volunteers, from 20 to 35 years, were studied after an overnight fast and in a resting phase. Nine of them were injected i.v. at 09.00 h with calcium (180 mg Ca in 20 ml), nine controls received the same volume of 0,9% NaCl. Plasma PRL, calcium, PTH, and urinary cyclic AMP were determined just before i.v. injection and 1, 2 and 3 hours later. In the controls, plasma PRL was decreased after the i.v. injection of 0.9% NaCl. Plasma calcium, PTH and urinary cyclic AMP levels were unchanged. In the calcium treated-group, plasma PRL, PTH and urinary cyclic AMP decreased progressively. No significant difference in plasma PRL levels was observed between the two groups. A rise in plasma calcium produced by i.v. calcium injection (+ 1 mg/100 ml 1 hour after injection), sufficient to decrease plasma PTH and urinary cyclic AMP, did not change the plasma prolactin level in man.

Adult↗