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Biomedical subjects

I Nielsen

Publications and source records attributed to I Nielsen.

At least 91 records · Page 5Linked to original sources
PubMed1975

The effect of reduction in blood volume on plasma renin activity in man.

1. The blood volume was reduced by approximately 10% in nine adult humans. 2. Plasma renin activity was measured before and at intervals after the venesection. In seven subjects there was no significant change. In two subjects there was a slight but significant increase in plasma renin activity. 3. It is concluded that reduction in blood volume is not a major short-term factor in regulating renin production in humans.

Adult↗
PubMed1975

The early effects of intravenous frusemide on central haemodynamics, venous tone and plasma renin activity.

1. Nine paatients with clinically unimportant heart disease or benign essential hypertension were given frusemide intravenously during right-heart catheterization. 2. Pressures in both atria decreased rapidly and in parallel. The magnitude of the pressure decrease was clearly related to decrease in plasma volume loss. 3. Plasma renin activity increased significantly after 5 min (P less than 0-01), but did not correlate with plasma volume loss. 4. Venous tone in the forearm was unchanged. 5. It is concluded that the pressure reduction was secondary to plasma volume depletion through diuresis and that increased plasma renin activity was mainly caused by intrarenal changes.

Adolescent↗
PubMed1975

Hemodynamics, compartments and the renin-aldosterone system in chronic heart failure.

In 12 patients with chronic mitral or aortic disease plasma renin activity (PRA) and aldosterone secretion rate (ASR) were correlated to hemodynamics, kidney function, plasma and interstitial fluid volume, and plasma sodium concentration, both in the congestive state (I) and after sodium depletion (II). PRA (I) and ASR (I) were normal or slightly elevated and increased normally after sodium depletion. A significant inverse correlation between plasma concentration (I + II) and PRA (I + II) was found. Further an abnormal inverse correlation between increments in PRA and cumulative sodium loss was demonstrated. By contrast, no correlations were found between PRA and ASR on one hand and pressures, kidney function or compartments on the other, neither in I - elevated pressures in the atria, low renal plasma flow, large compartments, nor in II - reduced pressures and compartments, almost unchanged kidney function. It is concluded that PRA hardly plays any primary role in the maintenance of sodium and fluid retention in human chronic congestive heart failure.

Aged↗