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Biomedical subjects

M Safar

Publications and source records attributed to M Safar.

At least 271 records · Page 15Linked to original sources
PubMed1979

[Electrocardiographic evolution of severe medically treated hypertension].

Electrocardiographic finding were studied in 34 severe hypertensions submitted to antihypertensive therapy. The duration of the survey was between 2 and 6 years. No significant correlation was observed between the changes in pressure and the changes in electrocardiogramm: normalisation of blood pressure could be associated with abnormalities in the electrocardiogramm, concerning especially ST segments and T waves. In the latter case, a high frequency of coronary insufficiency was observed. The results suggested that cardiac factors, independent of the pressure level, could determine the electrocardiographic changes during antihypertensive therapy.

Adult↗
PubMed1978

[Essential hypertension: long term haemodynamic effects of a diuretic combination (cyclothiazide-triamterene) (author's transl)].

The long terme hemodynamic effect of cyclothiazide 3 mg-triamterene 150 mg was studied in 10 patients with permanent essential hypertension. Diuretic therapy induced a significant fall in blood pressure (p less than 0.001) and total peripheral resistance (p less than 0.01), without significant change in cardiac index or blood volume. The result suggests that adaptative mechanisms of the circulatory system determine the decrease of blood pressure, independently of the pharmacological effect of the drug.

Adult↗
PubMed1978

Prostaglandins in renovascular and renal hypertension.

PG A1, B1, E2, F1,2alpha and PRA have been measured in 8 hypertensive patients with unilateral renal arterial stenosis, 7 hypertensive patients with unilateral renal atrophy and 20 control normotensive subjects. PRA and PGA1 were significantly increased in patients with renovascular hypertension but not in patients with atrophy. PGE2 and PGF1,2alpha were increased in both groups of patients, especially on the stenotic or atrophic side. The increase of PGA1 and PGE2, represents a secondary antihypertensive, diuretic and natriuretic mechanism, the increase of PGF1,2alpha a direct hypertensive mechanism.

Adolescent↗
PubMed1978

[Evaluation of cardiac performance in the hypertensive patient. Effect of a beta-blocking agent: atenolol].

Cardiac output (isotopic dilution method) and systolic time intervals were studied in 11 sustained and 8 borderline essential hypertensive patients, before and after intravenous administration of atenolol, a potent beta-blocking agent. Atenolol decreased significantly (p less than 0.01) cardiac output and heart rate. In borderline hypertensives, the preejection periods were significantly reduced. Atenolol prolonged the preejection periods more significantly (p less than 0.01) in borderline than in permanent hypertensives. Non invasive hemodynamic technics enabled the cardiac performance to be evaluated in hypertensives and the contribution of neurogenic factors in borderline hypertension to be estimated.

Atenolol↗
PubMed1978

Long-term blood pressure changes in renal homotransplantation.

Long-term blood pressure changes were studied in 50 patients who had undergone renal homotransplantation. Excluded were those subjects with arterial stenosis of the transplanted kidney, acute or rapidly progressive rejection, or recurrent glomerulonephritis, as well as those retaining their own diseased kidney(s). The blood pressure after the end of the first year was stable and, therefore, was utilized as the reference blood pressure for this study. One year after transplantation, hypertension was observed in 20% of the patients. Mean blood pressure was positively correlated with age (P less than .01), body weight (P less than .001), and serum creatinine level (P less than .001), and negatively correlated with maintenance dose of prednisone (P less than .01). A higher incidence of hypertension was observed in cadaver kidney transplantation than in living related-donor transplantation. The study minimizes the role of glucocorticoids and emphasizes the role of renal factors in the mechanism of the long-term blood pressure changes.

Adult↗
PubMed1977

[The sympathetic nervous system inhibition in the antihypertensive effect of beta-blockers (author's transl)].

The decrease of sympathetic activity by the beta-blocking drug, as demonstrated by the decreased electric activity of the splanchnic nerve and by the decreased urinary catecholamine reponse to tilt as well as by the decreased levels of plasma dopamine beta-hydroxylase exists not only in hypertension with elevated PRA but also in hypertension with normal or low PRA. In these latter cases the antihypertensive effect is better explained by the decrease in the sympathetic nervous system activity than by the decrease of PRA. This effect seems to be indirect and probably, as suggested by Lewis, as a result of damping sensory input to the central nervous system from the heart, whose capacity to respond to exercice and stress is blunted by beta-adreno-receptor blockade.

Adrenergic beta-Antagonists↗
PubMed1977

[Systemic arterial hypertension: pathogentic role of the sympathetic nervous system].

Role of the clinical and experimental data suggesting the role of the sympathetic nervous system in some essential hypertension are reviewed: increase in heart rate and diastolic blood pressure during orthostatism, increase in cardiac output resulting from increase in cardiopulmonary blood volume and/or in myocardial contractility, increase in peripheral resistances, elevated plasma catecholamines and dopamine-bêta-hydroxylase, disturbances in arterial baroreceptor sensitivity and in vascular response to adrenergic stimuli, elevated plasma renin activity. It appears that the role of a sympathetic overactivity is mainly important in labile hypertension with hyperkinetic syndrome and elevated plasma renin activity.

Animals↗
PubMed1977

[The relation between anti-hypertensive action and plasmatic concentration of pindolol. Preliminary study].

A correlation study between the antihypertensive effect and the plasma level of pindolol was performed in 10 patients with permanent essential hypertension. Pindolol was given orally (20 mg/day) during 9 days. The highly significant fall in blood pressure (delta SBP and delta DBP) is directly correlated negatively correlated, to the pretreatment pressure (p less than 0.02 for deltaSBP and p less than 0.05 deltaDBP) and negatively correlated to the pindolol plasma level (P less than 0.001 for delta SBP and p less than 0.05 for delta DBP). Multiple regression analysis shows, for delta SBP, a stronger influence of plasma level than of basal blood pressure. These results suggest that pindolol could have a specific effect in some hypertensive patients.

Adult↗
PubMed1977

Relationship between glomerular filtration rate and tubular reabsorption of sodium in patients with unilateral renal artery stenosis. The role of the renal prostaglandins.

In patients with renovascular hypertension, a significant decrease in glomerular filtration rate (GFR) and in renal plasma flow (RPF) in the stenotic kidney was accompanied by a significant homolateral decrease in extraction of PAH(EPAH) and in net tubular reabsorption of sodium (RNa). There was a highly significant correlation between differences in RNa and differences in either GFR or RPF, while no correlation between differences in RNa and in EPAH was noted. It is suggested that the nature of the relationship between GFR and RNa is essentially the same in unilateral renal artery stenosis in man, as in acute constriction of the renal artery or the aorta in the experimental animal.

Absorption↗
PubMed1977

Renovascular hypertension: the role of nonspecific factors in the antihypertensive effect of surgery.

Effective surgical treatment was carried out in 67 patients who were selected from a population of 336 subjects with renovascular hypertension. Split renal function studies and estimation of plasma renin activity in both renal veins were made to demonstrate the functional significance of the stenosis. The degree of disturbance of these tests did not correlate with the preoperative blood pressure level. The percentage decrease in postoperative blood pressure was directly related to the preoperative blood pressure (P less than 0.01). In 23 postoperative patients followed yearly for 5 years, the blood pressure increased progressively and was positively correlated with the duration of follow up (P less than 0.02). Patients with renovascular hypertension had a lower frequency of blood group 0 and a higher frequency of blood group A than did normotensive controls. The results of the study suggest that, in renovascular hypertension, the antihypertensive effect of surgical treatment is not exclusively related to the physiological consequence of the stenosis and that nonspecific factors, possibly of genetic origin, may determine the blood pressure response after surgical treatment.

Adult↗
PubMed1976

Direct relationship between urinary prostaglandin E and sodium excretion in essential hypertensive patients.

Urinary prostaglandins (PGEs and PGFs), sodium and potassium were measured in 17 essentially hypertensive patients. Significant positive correlations were found between a) PGEs secreted in 24 h and sodium excreted in 24 h, b) the ratio PGEs/UnaV before and PGEs/UnaV after volume expansion and c) the ration Na/K and urinary PGEs. It was suggested that renal PGEs, potent natriuretic and diuretic substances, play an important homeostatic role in the extracellular fluid regulation, and consequently in long-term control of the arterial blood pressure.

Adult↗
PubMed1976

Deficiency in renomedullary prostaglandin synthesis related to the evolution of essential hypertension.

Continued PG synthesis in the early stages of essential hypertension might reflect an activation of the renal antihypertensive function in respect to neurogenic and/or hormonal pression stimuli, subsequently a deficiency of renal PG synthesis related to irreversible changes with the kidney would lead to the prepoderance of a pressure mechanism, resulting to a further increase of blood pressure.

Adult↗