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Biomedical subjects

M Safar

Publications and source records attributed to M Safar.

At least 289 records · Page 16Linked to original sources
PubMed1976

Radioimmunoassay of prostaglandins A and B in human blood.

A highly sensitive radioimmunoassay for the measurement of plasma prostaglandins A and B, expressed in equivalents of PGA1, is described. This method was used for the measurement of prostaglandins A and B (PGA/B) in 23 healthy volunteers and 25 hypertensive patients. The PGA/B concentration in peripheral venous plasma of 23 healthy normotensive subjects is 115 +/- 15 pg/ml. The repeated measurement of the same plasma samples kept frozen for 60 days at -20 degrees C shows mean 194% increase of PGA/B concentration. The major site of synthesis of PGA/B seems to be the kidney. However in two patients PGA/B concentration in arterial blood was greater than in venous blood suggesting the possibility of cardio-pulmonary synthesis. The major site of inactivation is the hepatic circulation, as PGA/B concentration in hepatal venous blood is by 30% lower than in vena caval blood. The arterial concentration is 3% lower than venous PGA/B demonstrating very low pulmonary inactivation. Therefore the prostaglandins of the A and B series may represent a "circulating hormone". The plasmatic PGA/B is significantly increased in reno-vascular and essential hypertension.

Adult↗
PubMed1976

[Labile arterial hypertension and sympathetic tonus. Hemodynamic study].

Cardiac output, cardiopulmonary (CPBV) and total (TBV) blood volumes, vascular reactivity to norepinephrine and dopamine B hydroxylase (DBH) were determined in 41 borderline hypertensives patients in comparison with 28 normal subjects. Cardiac output (P less than 0.001) and CPBV/TBV ratio (P less than 0.01) were significantly increased. The ratio was directly correlated to the pressor-response to norepinephrine (P less than 0.01) and the DBH level (P less than 0.005). The results suggest that sympathetic overactivity plays a dominant role in the cardiac output elevation of borderline hypertensive patients.

Adult↗
PubMed1975

[Treatment of arterial hypertension with acebutolol. Double-blind study with placebos].

Acebutolol, a cardioselective beta-blocker, was studied at doses of 600 to 800 mg in a double-blind trial against placebo in 33 patients with essential hypertension. A moderate reduction in the arterial pressure was seen with placebo, but the pressure was greatly reduced by treatment with acebutolol (p less than 0,01). The heart rate was unchanged after placebo and was reduced by about 10 p.cent by acebutolol. Similarly plasma renin activity, in both lying and standing subjects, was not changed by the placebo, but it was greatly reduced by acebutolol. In the 33 patients studied, the arterial pressure returned to normal in 13 cases (39 p.cent), an improvement was obtained in 12 cases (36 p.cent) but in 8 cases (24 p.cent) the hypertension was not modified by acebutolol. The tolerance to acebutolol was excellent in all cases. No relationship was found between the hypotensive effect of acebutolol and the heart rate or its augmentation induced by orthostatism nor with the levels of plasma renin activity.

Acebutolol↗
PubMed1975

[Medically treated severe arterial hypertension. Long term course].

Antihypertensive therapy was performed in 47 patients having severe or malignant hypertension. The duration of the survey was two years. A highly significant decrease in blood pressure was observed. The decrease was not dependent on the type of antihypertensive treatment. Renal function was reduced at the beginning of the treatment. The renal insufficiency partly or totally diminished in course of time. Coronary insufficiency was noted in 5 patients. Coronarography showed thrombotic atherosclerosis in only one patient. A significant increase in lipids, cholesterol and triglycerids was nearly constant. The meaning of such facts is discussed.

Antihypertensive Agents↗
PubMed1975

The release of renal prostaglandins during saline infusion in normal and hypertensive subjects.

1. Renal venous prostaglandin concentrations (PGA, PGE and PGF) were determined, together with renal plasma flow, urinary output and blood pressure changes, before and after infusion of sodium chloride solution (saline) in four normotensive and three hypertensive subjects. 2. No changes in blood pressure and in glomerular filtration rate were observed. 3. Saline infusion induced a significant increase in renal venous PGA and PGE, and also in total and non-cortical renal plasma flow and urinary output. There was an insignificant increase in renal venous PGF. 4. These findings show that prostaglandin release after saline infusion is associated with changes in renal blood flow and suggest that the natriuretic and diuretic effect of saline could be the result of prostaglandin release.

Adult↗
PubMed1975

Prostaglandins and hypertension in chronic renal diseases.

The role of prostaglandin A (PG A) in the pathogenesis of renal hypertension has been studied. The concentration of endogenous PG A was measured in the peripheral plasma by radioimmunoassay in patients with chronic renal disease and in control subjects. The mean plasma concentration of PG A1 equivalents was as follows: 1. normotensive healthy volunteers (n=23): 115 +/- 15 pg/ml 2. patients in terminal renal failure on regular hemodialysis a) anephric patients (n=6): 51+/- 21 pg/ml b) patients retaining their own kidneys, all but one with hypertension (n=9): 231 +/- 51 pg/ml (P less than 0.01 versus control) 3. patients with chronic renal disease a) with hypertension (n=7): 204 +/- 60 pg/ml (P less than 0.01 versus control) b) without hypertension (n=11): 136 +/- 30 pg/ml. Renal hypertension was associated with high levels of PG A in peripheral blood. This increase is probably a secondary adaptative mechanism for the excretion of a greater fraction of the glomerular filtrate at a lower blood pressure. PG A may represent a circulating "antihypertensive hormones".

Adult↗
PubMed1975

[Use of propranolol in permanent essential hypertension].

The anti-hypertensive effect of propranolol is studied in 35 essential permanent hypertensive patients. The decrease in blood pressure in higher in the presence (p is less than 0.01) than in the absence of diuretic therapy. The anti-hypertensive effect is higher in severe than in moderate hypertension. No side effect was observed except the decrease in heart rate (p is less than 0.001). Dihydralazine was added in 4 severe hypertensive patients and induced in 2 of them anginal attacks.

Adult↗
PubMed1975

[Electrocardiography of the hypertensive patient: correlations with hemodynamic parameters].

A comparative study between electrocardiographic signs of left ventricular hypertrophy and haemodynamic parameters is performed in 184 permanent hypertensive patients. They are divided into 3 groups taking into account the level of electrocardiographic changes. Patients with a normal electrocardiogram have a slight increase in arterial pressure, an increase in cardiac index (P is less than 0.01) and total peripheral resistances (P is less than 0.001) and a reduction of plasma volume (P is less than 0.001). Patients with a moderate change in their electrocardiogram have normal cardiac output, high peripheral resistances (P is less than 0.001) and a slight decrease in plasma volume (P is less than 0.05). Patients with a left major ventricular hypertrophy have a reduced cardiac output (P is less than 0.01), increased peripheral resistances (P is less than 0.001) and a normal plasma volume. The significance of such facts, especially concerning the hemodynamic response in upright position, is discussed.

Adult↗