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Biomedical subjects

A Simon

Publications and source records attributed to A Simon.

At least 469 records · Page 26Linked to original sources
PubMed1982

[Pharmacokinetics of isosorbide dinitrate administered by intravenous infusion to hypertensive patients (author's transl)].

The pharmacokinetics of intravenous isosorbide dinitrate was investigated in 11 patients with labile hypertension and with normal renal and hepatic functions. The mode of administration (constant rate infusion without loading dose) was chosen in order to minimize side-effects and to approximate clinical conditions. Isosorbide dinitrate levels were measured by electron-capture gas chromatography. The volume of distribution during steady state (Vd beta = 318 +/- 117 I) and the elimination half-life (t1/2 beta = 64.8 +/- 30.5 min) were similar to those found after perlingual and oral administration. Systemic clearance (Cls = 3.80 +/- 1.48 I/min) was high for a drug given intravenously, presumably because of active hepatic extraction, intensive pre-systemic degradation and very active extra-hepatic metabolism. These findings should be compared with the considerable inter-individual variations observed in theoretical plasma concentrations during steady state and with the presence of two pharmacokinetic models (one -- and two -- compartments) in the patients under study. Comparison of the results obtained by the intravenous route with previously published results after perlingual and oral administration indicates the following bioavailability ratios: perlingual/i.v. = 31%, oral/i.v. = 20%, and oral/perlingual = 63%.

Female↗
PubMed1982

Effects of captopril on prostaglandin and natriuresis in patients with essential hypertension.

The antihypertensive, renal and hormonal effects of captopril were studied in 10 patients with essential hypertension. Captopril significantly decreased arterial blood pressure with a concomitant increase in glomerular filtration rate, natriuresis and kaliuresis and a significant selective increase in urinary (renal) prostaglandin E2; other plasma and urinary prostaglandin (F2 alpha, 6-keto-prostaglandin F1 alpha; thromboxane B2) were not significantly changed. The urinary prostaglandin E2 increase was observed even in patients with pretreatment subnormal prostaglandin E2 excretion. Increases in urinary prostaglandin E2 were significantly positively correlated with increases in urinary sodium concentration. It is concluded that the antihypertensive effect of captopril is mediated, at least partially, by prostaglandin E2 release from renal and extrarenal tissues. Captopril enhances natriuresis at a lower perfusion pressure.

Blood Pressure↗
PubMed1982

Cytochrome P-450-Dependent omega-Hydroxylation of Lauric Acid by Microsomes from Pea Seedlings.

Microsomes from apical buds of pea (Pisum sativum L. var. Téléphone à rames) seedlings hydroxylate lauric acid at the omega-position. This oxidation is catalyzed by a cytochrome P-450 enzyme which differs from laurate hydroxylases previously described in microorganisms and mammals by its strict substrate specificity and the ability of low NADH concentrations to support unusually high oxidation rates. The apparent K(m) for lauric acid was 20 micromolar. NADPH- and NADH-dependent laurate hydroxylation followed non-Michaelian kinetics with apparent K(m) values ranging from 0.2 to 28 micromolar for NADPH, and 0.2 to 318 micromolar for NADH. When induced by the photomorphogenic photoreceptor phytochrome, the time course for the enhancement of laurate omega-hydroxylase was totally different from that of the cinnamic acid 4-hydroxylase, providing evidence for the existence of multiple cytochrome P-450 species in pea microsomes.

Journal Article↗
PubMed1982

Sex-related patterns of worry in secondary school pupils.

This investigation sought data concerning sex differences in the worry patterns of children. The sample comprised 182 comprehensive school pupils, 91 boys and 91 girls, between the ages of 12 years 1 month and 13 years 7 months. The Simon-Ward Worry Survey (1976) was administered in order to ascertain the frequency and intensity of worry experienced in the following areas; family, school, economic, social, personal adequacy, health, imagination and animals. Both in the frequency and intensity of worry girls scored higher than boys in the areas of family, social and imagination, but no significant differences occurred for personal adequacy, health, animal or economic factors. For both sexes the category order, from highest to lowest, was the same--family, social, school, imagination, personal adequacy, health, economic and animals.

Adolescent↗
PubMed1982

[Self-healing childhood histiocytosis X (Illig-Fanconi disease). Comments on ultrastructural aspects and etiopathogenic classification of histiocytosis].

Two cases of cutaneous self-healing histiocytosis X in a 6 and a 16 months-old children, are reported. Clinically, the lesions were characterized by few, small, translucent and confluent papules, sometimes purpuric. The scalp lesions were seborrheic eczema-like; the elements on the groins were erosive. Systemic examinations, laboratory data and general development were completely normal. The histological pattern, in both cases, were identical of that in histiocytosis X (atypic mononuclear cells with glassy eosinophilic cytoplasm and excentric kidney-shaped nucleus). Electron microscopy of the second case showed a proliferation of histiocytes containing Langerhans bodies. Ten per cent of these cells showed multivesicular, myelin and dense laminar bodies. The latest had been specially described in other selfhealing histiocytic syndromes: congenital reticulohistiocytosis (Hashimoto-Pritzker) and generalized eruptive histiocytoma. Since the clinical behaviour and prognosis of the histiocytic proliferations can not be assumed on clinical and histological data, an attempt, of classification and understanding of these processes is presented. The possibility that histiocytosis represent a proliferation of the mononuclear-phagocytic system at different levels of cellular maturation, is considered. So it would be possible to consider: 1) Acute malignant processes: xantholeukaemia, malignant histiocytosis syndromes (histiocytic medullary reticulosis . . .), and Letterer-Siwe disease; 2) Chronic and severe processus: xanthoma disseminatum, necrobiotic xanthogranuloma, disseminated plane xanthoma, multicentric reticulohistiocytosis, localized reticulohistiocytoma of Crosti and Hand-Schüller-Christian disease; and 3) Benign processus, some of them being involutive: juvenile xanthogranuloma, regressing atypical histiocytosis, eosinophilic granuloma of the bone, Illig-Fanconi disease, Hashimoto-Pritzker disease, benign cephalic histiocytosis and generalized eruptive histiocytoma. These groups include classic X-histiocytosis, self-healing X-histiocytosis, non-X malignant histiocytosis and non-X benign or auto involutive-histiocytosis (some with intracellular lipid storage: xanthohistiocytosis) (see table II). The ultrastructural cytoplasmic markers of histiocytosis (table I) are consistent features in the accuracy of diagnosis of these conditions.

Female↗
PubMed1982

[Urinary thromboxane B2 in hypertensive patients].

UNLABELLED: Thromboxane A2 (TxA2) is a vasoconstrictor synthetized by the kidney. Its role in hypertension is unknown. We measured urinary TxB2 (the metabolite of renal TxA2) by radioimmunoassay and studied renal functions in 15 borderline, 15 sustained essential hypertensive patients and 12 age-matched normotensive subjects (6 young and 6 older adults). Results were as follows: Normotensive subjects: Mean arterial blood pressure (MBP) 97 +/- 2 mmHg, urinary TxB2 (UTxB2V) 159 +/- 12 pg/min, glomerular filtration rate (GFR) 120 +/- 8 ml/min, sodium excretion (UNaV) 73 +/- 9 mueq/min. Hypertensive patients: MBP 115 +/- 2 mmHg (p less than 0,001 vs controls), UTxB2V 298 +/- 24 pg/min (p less than 0,005), GFR 128 +/- 6 ml/min, UNaV 51 +/- 4 mueq/min (p less than 0.02). There was a positive significant correlation between UTxB2V and GFR (p less than 0,005) and between UTxB2V and UNaV (p less than 0,005) in hypertensive but not in normotensive subjects. There was no correlation between GFR and UNaV in either group. CONCLUSION: 1. Urinary (i.e. renal) TxB2 is significantly elevated in hypertensive patients; 2. TxA2 may be a mediator of pressure natriuresis.

Adolescent↗
PubMed1982

[Systolic arterial hypertension: demonstration and mechanism in obliterating arteriopathy of the lower extremities].

Hemodynamic parameters were measured in 24 patients with arteriosclerosis obliterans of the lower limbs, in comparison with 16 normal subjects of same age. Systemic arterial compliance was estimated from a simple visco-elastic model. In patients with arteriosclerosis obliterans, systolic pressure was significantly increased (P less than 0.001) while diastolic pressure remained within normal ranges. Arterial compliance was reduced (P less than 0.01) and was negatively correlated with systolic pressure (r = -0.72). Intravenous administration of nitroglycerin significantly decreased systolic pressure (P less than 0.05) and increased arterial compliance (P less than 0.01) without any change in mean arterial pressure. This study provided evidence that, in patients with arteriosclerosis obliterans of the lower limbs, the reduced systemic arterial compliance contributes in the increase in systolic pressure.

Arterial Occlusive Diseases↗
PubMed1982

[Comparative hemodynamic effects of 2 vasodilators: dihydralazine and diltiazem in permanent essential arterial hypertension].

Cardiac hemodynamic and diameter, blood flow velocity, volumic flow of the brachial artery measured by pulsed Doppler, were studied before and after diltiazem administration in comparison with dihydralazine in hypertensive patients. After diltiazem administration, blood pressure and total peripheral resistance significantly decreased (P less than 0.001) while cardiac index and heart rate increased (P less than 0.01). After 25 minutes perfusion cardiac output and heart rate returned toward control values, while blood pressure and total peripheral resistance remained decreased. The result contrasted with those observed after dihydralazine, which induced an increase in cardiac index and heart rate. The caliber of the brachial artery decreased significantly (P less than 0.001) after dihydralazine and increased after diltiazem (P less than 0.01). This study shows that 1). The antihypertensive effect of diltiazem was due to a fall in total peripheral resistance associated with a transient baroreflex mediated tachycardia, and 2) diltiazem dilated also large arteries.

Adult↗
PubMed1981

Hypotensive effects of xipamide in essential hypertension. Crossover comparison with hydrochlorothiazide.

Twenty-nine patients with mild to severe essential hypertension were treated with titrated doses of xipamide, before or after treatment with 50 and , if necessary, 100 mg hydrochlorothiazide in a 13- to 25-week open crossover study. Based on supine diastolic pressure readings taken at weekly intervals, xipamide controlled hypertension in all subjects: 17 achieved control with a daily dose of 5 mg; seven, with 10 mg; and five, with 20 mg. In contrast, eight of the 29 patients could not be controlled with 100 mg/day hydrochlorothiazide. The only significant biochemical change observed was an increase in serum uric acid in 12 patients after hydrochlorothiazide but in only six patients after xipamide. Natriuresis was comparable after both drugs; 5 and 10 mg xipamide were as effective as 50 and 100 mg hydrochlorothiazide. The only side effect noted, cramping due to hypokalemia, occurred during treatment with hydrochlorothiazide, but not xipamide, and was reversed by potassium supplements.

Adult↗
PubMed1981

Pulsed Doppler: determination of diameter, blood flow velocity, and volumic flow of brachial artery in man.

A pulsed Doppler velocimeter suitable for the determination of blood flow velocity and volumic flow in peripheral arteries is described. The apparatus has two main characteristics: an adjustable range-gated time system and a double transducer probe. The error in the determination of the angle between the ultrasound beam and flow of blood with this apparatus was less than 2%, and overestimation of the arterial diameter due to the sample volume size did not exceed 0.035 +/- 0.015 cm. The apparatus was used to determine diameter, blood flow velocity and volumic flow of the brachial artery of 22 healthy men. The values were respectively 0.440 +/- 0.010 cm, 9.15 +/- 1.01 cm.s-1 and 85 +/- 10 cm3.min-1. Administration of intravenous nitroglycerin significantly increased the arterial diameter (p less than 0.001) without any significant change in volumic flow. The described pulsed Doppler velocimeter provides an accurate noninvasive method for determining volumic flow in peripheral arteries in clinical investigation and cardiovascular pharmacology.

Adult↗
PubMed1980

Sotalol.

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Arrhythmias, Cardiac↗
PubMed1980

[Anti-hypertensive action of Captopril. Hemodynamic study (author's transl)].

Hemodynamic parameters were studied before and after administration of SQ 14 225, an orally active converting enzyme inhibitor, in 6 sustained essential hypertensive patients. Blood pressure and total peripheral resistance significantly decreased while cardiac output and heart rate remained unchanged. Systolic time intervals and plasma volume were not modified. No correlation was observed between the basal value of plasma renin activity and the decrease in blood pressure. The study demonstrated the vasodilatator effect of SQ 14 225 and questionned the role of the renin-angiotensin system in the mechanism of the pressure decrease.

Adult↗