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Biomedical subjects

G Annat

Publications and source records attributed to G Annat.

64 records · Page 4Linked to original sources
PubMed1978

Influence of renal nerves on renin secretion in the conscious dog.

In order to evaluate the influence of renal nerves on renin secretion during changes in blood volume, we studied the mean arterial blood pressure (MAP) and the renal venous plasma renin activity (PRA) in 6 conscious dogs having one intact and one denervated kidney. After a passive head-up tilt PRA increased significantly in the vein of the intact kidney while it remained stable in the denervated one. The intravenous injection of Furosemide (3 mg/kg) induced a rapid elevation of PRA in both renal veins. The kinetics of the variations of renin secretion were similar in the two kidneys, but its magnitude was significantly lower in the denervated side. After a slow hemorrhage of 2, 4 and 6 ml/kg, MAP was unchanged and PRA increased in both renal veins but in a significantly lower degree in the denervated side. When blood loss reached 8 ml/kg, MAP decreased and PRA increased identically in the two renal veins. It was concluded that, in conscious dogs, the renal nerves could participate in the rapid adaptations of renin secretion during small changes in the circulating blood volume.

Animals↗
PubMed1978

Correlation between evolution and treatment of hypertension in unilateral renal disease and values of renin activity in renal venous blood.

93 patients with renal hypertension and renal vein PRA determination were studied during 1--5 years follow-up. They were separated in two groups of medical and surgical treatment. Medical treatment is able to normalize blood pressure even in cases with high asymmetric PRA. 9 of 16 patients could be cured or improved in the surgical group and 14 of 22 in the medical group. The best results were obtained if beta-blockers were included in the drug regimen: cured or improved were 7 of 33 patients in medical treatment without beta-blockers, 17 of 28 in surgical treatment, and 31 of 32 in medical treatment including beta-blockers with or without hydralazine and/or diuretics.

Adolescent↗
PubMed1978

Maternal and fetal plasma renin and dopamine-beta-hydroxylase activities in toxemic pregnancy.

Toxemic and normotensive pregnant women were compared for plasma renin activity (PRA), aldosterone (PA), and dopamine-beta-hydroxylase (DBH). At term, hypertensive patients exhibited higher levels of PRA and PA, but similar levels of DBH, progesterone, and estradiol. Their elevated blood pressure was significantly correlated to their levels of PRA. During the delivery levels of PRA increased significantly in toxemic patients in spontaneous labor. Venous and arterial cord PRA levels were higher in babies born to hypertensive mothers than in babies born to normotensive mothers. Three days postpartum, maternal PRA level was lower than at term. Seven days postpartum, PRA levels remained higher in toxemic than in normal women. Maternal DBH levels did not change during and after delivery. Levels of DBH were undetectable in cord blood. We conclude that the renin-angiotensin system is involved in the pathogenesis of toxemia.

Adult↗
PubMed1977

[Treatment of a case of grave orthostatic hypotension (Shy-Drager's syndrome) by an association of L-dopa and mono-amine-oxidase inhibitor (author's transl)].

The authors report a case of grave orthostatic hypotension (Shy-Drager's syndrome) with major postural disturbances. The biological test confirmed a catecholaminergic deficiency. After several drugs were tried unsucessfully, an association of L-Dopa and fractionated doses of mono-amine-oxydase inhibitor was proposed. The increase blood pressure was sufficient to block the diturbances of postural adaptation, without inducing hypertensive jerks. The functionnal result have been stable for three years, while the parkinsonian syndrome have shown little progression.

Aged↗
PubMed1976

A kinetic study of plasma renin and aldosterone during changes of posture in man.

Cardiovascular parameters, hematocrit (Ht), plasma electrolytes, renin activity (PRA) and aldosterone concentration (PAC) were measured in 12 normal human subjects (6 males and 6 females) eating an ad lib diet. At 8 AM, volunteers assumed the following postural changes: 1 hour supine, then 2 hours upright and finally 1 hour supine. Orthostatism induced the following changes: heart rate, systolic and diastolic blood pressure increased immediately; Ht rose significantly at the 5th min in males but not in females; Plasma sodium showed no variations but potassium increased after 30 min; PRA rose significantly at the 5th min and, after 120 min of orthostatism, was found to be 3 times greater than its value after recumbency; and PAC increased significantly at the 15th min and exhibited a plateau 4.5 times its basal values after 90 min of upright posture. When subjects returned to the supine position all the parameters, except PAC decreased. During active orthostatism, a significant correlation was found between PAC and plasma potassium, but correlation was closer between PAC and PRA and between PAC and PRA + potassium. It can be concluded that the renin-angiotensin system is a more potent stimulus for aldosterone secretion than plasma potassium in normal man assuming postural changes. The results presented here can be applied to the development of a short posture test in non-hospitalized patients.

Adult↗
PubMed1976

Effects of right atrial stretch on plasma renin activity.

In anaesthetized dog, right atrial stretch leads in the first five minutes to a decrease in plasma renin activity, when measured in inferior vena cava just above the renal veins. Bilateral cervical vagotomy increases plasma renin activity. After vagotomy, atrial stretch no longer has any effect on plasma renin activity. The results support the hypothesis of a control of renin secretion originating from atrial volume receptors.

Animals↗