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Biomedical subjects

A Jindra

Publications and source records attributed to A Jindra.

At least 55 records · Page 3Linked to original sources
PubMed1978

Interrelations between plasma renin activity, aldosterone, and sympathetic nervous system activity in essential hypertension.

Interrelations were investigated between plasma renin activity (PRA), dopamine-beta-hydroxylase activity (DBH), plasma aldosterone (PA), plasma cortisol (PC) and plasma sodium concentration (PNa) in renal vein blood of essential hypertension patients in recumbent position. The patients were divided in compliance with the WHO classification into two groups of stage I and stage II of essential hypertension. In stage I a negative correlation was found in all samples of blood between PA and PNa. This means that in recumbent position in stage I the mechanism of regulation sodium -- aldosterone is maintained. In stage II there were very significant correlations between DBH and PRA in the samples from both renal veins. The left renal vein blood gives the best information about secretion of the left adrenal gland. In stage II in samples from the left renal vein a negative correlation was proved between PA and PRA, and also two very similar negative correlations PA -- DBH and PC -- DBH were demonstrated. The results indicate that in recumbent position in stage II the renin secretion is mainly under the control of the sympathetic nervous system, even if the activity of the latter is depressed, normal or enhanced. The possible negative relation between sympathetic activity and corticosteroid secretion in stage II of essential hypertension is discussed.

Adolescent↗
PubMed1972

Physiological studies on ergot: further studies on the induction of alkaloid synthesis by tryptophan and its inhibition by phosphate.

The failure of l-leucine to stimulate ergot alkaloid production in a synthetic medium indicates that the previously observed stimulation by tryptophan and tryptophan analogues does not merely represent a nutritional effect. Tryptophan, but not mevalonate or 5-methyltryptophan, is able to overcome the inhibition of alkaloid synthesis by high levels of inorganic phosphate. Therefore, high phosphate levels seem to limit the synthesis of tryptophan; they may, in addition, prevent induction of alkaloid synthesis by preventing accumulation of tryptophan. Experiments which indicate a 2- to 3-fold temporary increase of intracellular free tryptophan and a 20- to 25-fold increase of tryptophan synthetase activity during the transition period between growth and alkaloid production phase are in agreement with the previously postulated induction of alkaloid synthesis by tryptophan. The latter experiments also indicate 4- to 6-fold repression of this enzyme by tryptophan.

Amino Acids↗