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Biomedical subjects

A Mimran

Publications and source records attributed to A Mimran.

At least 217 records · Page 12Linked to original sources
PubMed1981

[Effect of captopril in essential hypertension (author's transl)].

The angiotensin I-converting enzyme inhibitor, captopril (SQ 14225) was proposed as first treatment in 12 cases of uncomplicated essential hypertension maintained on unrestricted sodium intake (group I). Arterial pressure was normalized in 7 patients (subgroup Ia) whilst hydrochlorothiazide was added to captopril in 5 patients (subgroup Ib). A significant dose-response curve between the dose of captopril (range 75 to 450 mg/day) and the antihypertensive effect was obtained with a maximum at 300 mg/day. In 8 patients (group II) hydrochlorothiazide was proposed first and the addition of captopril was necessary in 4 cases. No relationship between pretreatment PRA and the maximum effect of captopril was observed (r = -0.34, NS). No disturbance of upright blood pressure regulation was noted. Adverse reaction consisted of 4 cases of benign and spontaneously regressive skin rash or pruritus.

Adult↗
PubMed1981

[Treatment with captopril of idiopathic edemas (author's transl)].

The angiotensin-converting enzyme inhibitor captopril (SQ 14225, 50 mg tid) was used for treating a patient with idiopathic edema. A marked improvement of clinical condition was achieved as confirmed by the significant decrease in the morning-evening weight difference during treatment. No disturbance of arterial pressure regulation as well as side effects were observed after a 22 month-period of treatment. This observation which needs further studies brings a new approach of the treatment of patients with idiopathic edema.

Adult↗
PubMed1981

Shunting in renal microvasculature of the rat: a scanning electron microscopic study of corrosion casts.

We reinvestigated the still controversial existence of arterial pathways by-passing glomeruli within kidneys of rats from weaning to more than 12 months old (i.e., body weight ranging from 39 g to 643 g). For this purpose, the arterial injection of microspheres 7.5 micrometer to 17 micrometer in diameter was combined to corrosion-replication of the arterial bed of a vasodilated perfused kidney preparation. This procedure allowed easy detection of arterial by-passes with light microscope and detailed observation with scanning electron microscope. Our results clearly demonstrate the existence of various categories of arterial by-passes throughout renal cortex regardless of age. Some of them had never been described before. These vascular by-passes were found with increased frequency from superficial to juxtamedullary cortex. In the latter area, frequency was not age-dependent, and approximately 10% (range 4-22%) of juxtamedullary glomeruli were involved. Data derived from previous microsphere studies would suggest that these structures are (partially) nonfunctioning in basal physiological conditions, but more information is needed to assess their possible functional role in the rat.

Animals↗
PubMed1981

The antihypertensive action of indapamide: results of a French multicentre study of 2,184 ambulant patients.

A multicentre study was carried out by 300 French general practitioners to evaluate the efficacy and acceptability of indapamide in a single daily dose of 2.5 mg in 2,184 patients with essential hypertension. There was a significant reduction in blood pressure, 65.7% of the patients attaining a normal blood pressure. In addition, it was found that indapamide produced an excellent reduction in blood pressure in severely hypertensive patients, including those on combined therapy with a beta-blocker. The elderly patients were found to benefit from the simple dosage and the lack of side effects such as postural hypotension. There was little change in any of the biochemical measurements.

Adrenergic beta-Antagonists↗
PubMed1981

[Evaluation of the acute effect of a converting enzyme inhibitor, captopril, in normal and hypertensive subjects].

The response to acute oral administration of 50 mg of Captopril was assessed in 17 normal volunteers and 47 patients with hypertension; 17 had renovascular (RVH) abnormalities and 30 patients had essential hypertension (EH). All patients were maintained on ad libitum sodium intake. The effect of Captopril on mean arterial pressure (MAP) was rapid a maximal within 60 minutes. The converting enzyme inhibitor induced a similar decrease in MAP in normal subjects (-5.1 +/- I mm Hg) and patients with EH (-7.2 +/- I mm Hg). Control plasma renin activity (PRA) was similar in both groups; however, the increase in PRA following Captopril was more marked in normals (8.1 +/- 1.7 ng/ml/h) than in EH (1.7 +/- 0.7 ng/ml/h). In patients with RVH a marked fall in MAP occurred (-25.4 +/- 4 mm Hg). A fall in MAP higher than 20 mm Hg was observed in 65% of patients with RVH and none of the EH group. A negative correlation between log PRA and the change in MAP induced by Captopril was obtained (r = 0.65). Assessment of the response to acute administration of Captopril may be useful for screening patients with RVH.

Adult↗
PubMed1981

Effect of captopril on the systemic and renal responses to acute isotonic volume expansion in normal man.

Systemic, humoral and renal responses to isotonic volume expansion (VE, 1800ml in 3 hours) were assessed in normal subjects before and during captopril administration (CEI). Captopril, which otherwise induced a decrease in pre-saline mean arterial pressure (MAP) unmasked the volume-dependence of MAP since during captopril administration MAP increased linearly during volume expansion (+18.7 +/- 3.8% at the end of VE). In addition, captopril prevented the fall in plasma aldosterone produced by VE but did not modify the natriuretic response to saline. These results demonstrate that circulating angiotensin II is not an important determinant of the natriuretic response to volume expansion in normal man. However, a role for intrarenal renin cannot be excluded.

Adult↗
PubMed1981

[Effect of indomethacin on renin secretion in isolated perfused rat kidney (author's transl)].

In vivo administration of indomethacin (I) is associated with a decrease in basal and stimulated plasma renin activity in man and other animal species including the rat. In order to identify the mechanism(s) underlying the effect of I on renin secretion, studies were carried out using isolated rat kidneys perfused at a constant rate (5 ml/min) with cell-free medium. In this model, the infusion of I into the renal artery at concentrations ranging from 5.5 to 167 mumol/1 induced a dose-dependent and reversible increase in renal renin release. Although these effects were observed without variation in perfusion pressure and kidneys were non-filtering, no definitive conclusion may be drawn concerning their mediation by macula densa or baroreceptors from the present data. Inhibition of renal prostaglandin biosynthesis by I may play a role; however, another possible mechanism could be the inhibition of phosphodiesterase activity by I. Supporting this view was the finding that theophylline, a potent known inhibitor of phosphodiesterase activity mimicked the effect of indomethacin in our model.

Animals↗
PubMed1980

Indirect evidence against a role of the kinin system in the renal hemodynamic effect of captopril in the rat.

The effects of acute saralasin (SAR) and captopril (SQ) administration on arterial pressure (AP), plasma renin activity (PRA), urinary excretion of water and electrolytes, glomerular filtration rate (GFR), renal blood flow (RBF), and glomerular blood flow (GBF) distribution (microsphere technique) were assessed in rats with activation of the renal renin and kallikrein systems (that is, chronic sodium depletion). In both groups AP decreased, and PRA and RBF increased markedly. Blood flow to outermost (C1) glomeruli was (in nl/min/g of kidney wt) 270 +/- 35 in SAR and 219 +/- 20 in the SQ group (NS when compared to 208 +/- 9 in control chronically sodium-depleted rats). Blood flow to innermost glomeruli (C4) strikingly increased from 95 +/- 10 (control) to 216 +/- 21 (SAR) and 180 +/- 13 (SQ group). Hence, preferential vasodilatation of innermost glomeruli occurred (C1/C4 ratio of 2.18 +/- 0.27 in control, 1.26 +/- 0.11 in SAR, and 1.25 +/- 0.07 in SQ rats). Chronic (6 days) administration of SQ was associated with a rapid and marked increase in water and sodium excretion. At the end of the study, RBF was higher than control, and GBF distribution was similar to that observed in acutely treated rats (C1/C4 ratio of 1.16 +/- 0.10). These results suggest that angiotensin plays a significant role in the systemic and renal hemodynamic changes associated with chronic sodium depletion. The similarity of the changes induced by SAR and SQ provides an indirect evidence against an effective role of the renal kallikrein system in the effect of captopril.

Animals↗
PubMed1980

Measurement of cardiac output and its distribution in rats under various sodium intakes, using 15 and 10 micron spheres.

We estimated cardiac output and its distribution to organs using simultaneously injected 15 micrometers and 10 micrometers radioactive microspheres. This study was carried out in anaesthetised rats with high cardiac output induced by sodium loading and low cardiac output by sodium restriction. In neither group were the values of cardiac output and blood flow to kidneys, brain, heart and spleen affected by microsphere size. However, the ratio of blood flow estimated with 15 micrometer to that with 10 micrometer microspheres averaged 0.67: 0.60 for liver, 1.09: 1.10 for duodenum, 3.51: 3.52 for testes, and 1.19: 1.07 for adrenals in high and low sodium rats respectively. A significant escape of 10 micrometer microspheres from testicular, adrenal, and gastrointestinal vasculatures may explain such finding. With regard to the liver, this view was reinforced by the finding of comparable hepatic blood flow values with either bead size after clamping of the portal vein. Additional preferential losses of 10 micrometer microspheres from muscular vasculature seemed to contribute to the fractions of injected radioactivities recovered in lungs (that is 6 and 2% for 10 micrometer and 15 micrometer spheres respectively). These results suggest that in the rat blood flow data provided by 10 micrometer microspheres should be carefully analysed according to the organ(s) studied.

Animals↗
PubMed1979

Aglomerular pathways in intrarenal microvasculature of aged rats.

By means of silicone rubber injections, we confirmed the existence of several types of aglomerular arterial pathways within kidneys of aged rats. In superficial cortex some interlobular arteries divide to form aglomerular branches (Ludwig's arterioles) towards cortex corticis. In juxtamedullary cortex these pathways are relatively more numerous, they comprise: (a) Vasa Recta Vera, (b) glomeruli in which afferent and efferent arterioles form a continuous vessel and (c) glomeruli with two efferent vessels, one by-passing glomerular tuft. In addition, results obtained in the rat by the microsphere technique are in agreement with our morphological observations.

Animals↗
PubMed1979

Microsphere size and determination of intrarenal blood flow distribution in the rat.

The influence of microsphere size upon the estimation of cardiac output (CO), renal blood flow (RBF) and its cortical distribution (ICBFD) was evaluated by simultaneous injection of 8.5 +/- 0.8 micrometer (SD) and 12.7 +/- 1.7 micrometer (SD) spheres in control conditions and after hemorrhagic hypotension (HH rats). The values of CO and RBF were unaffected whilst the ratio of flow to outer and inner halves of cortex (OCF/ICF) was 32% higher with 12.7 micrometer than with 8.5 micrometer spheres in both groups. Microscopic analysis of cleared kidneys slices confirmed that large spheres were more concentrated in outermost and less concentrated in innermost glomeruli than small spheres. In addition, the ratio of sphere number per outermost to that per innermost glomerulus (fs/fjm), and approximation of glomerular blood flow distribution was 1.74 and 1.76 with large spheres and 0.98 and 1.06 with small spheres in control and HH rats respectively. It is concluded that the artifact due to sphere size was not minimized in low flow conditions (HH rats) and that 8.5 micrometer spheres may be a more realistic marker of glomerular blood flow distribution in the rat than 12.7 micrometer spheres.

Animals↗