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Biomedical subjects

A Fournier

Publications and source records attributed to A Fournier.

At least 469 records · Page 26Linked to original sources

Evaluation of vascular calcinosis risk factors in patients on chronic hemodialysis: lack of influence of calcium carbonate.

UNLABELLED: Linear calcifications of the abdominal aorta and of the iliac and femoral arteries were measured yearly for 3 years on X rays of 24 patients on chronic hemodialysis taking variable amounts of calcium carbonate and Al(OH)3 but no pharmacological doses of vitamin D or 1 alpha-hydroxylated vitamin D derivatives. The speed of their extension appeared exponential and covariant with the male sex, age only for men and, independently of these two factors, with diastolic blood pressure and blood triglycerides. Plasma concentrations of calcium, phosphate and glucose were covariant with the extension of calcinosis only at a borderline level. The doses of calcium carbonate and the levels of plasma alkaline phosphatase were not at all covariant. CONCLUSIONS: (1) The effect of high doses of calcium carbonate is possibly harmful only when supraphysiological levels of plasma calcium are induced, whereas plasma phosphate is not adequately decreased. The doses of calcium carbonate per se have no deleterious effect (2). Since alkaline phosphatase is not covariant with the extension of calcinosis, the degree of hyperparathyroidism per se does not seem to play a causative role in vascular calcinosis (3). The main risk factors of vascular calcinosis are: age, the male sex, diastolic blood pressure and blood triglycerides.

Adult↗

Electrophysiologic effects of intravenous propranolol in the intact immature mammalian heart.

Using intracardiac electrogram recording and stimulation techniques, 13 neonatal puppies (3-15 days) and 9 adult dogs were studied following cumulative doses of intravenous propranolol. Although propranolol caused a dose-dependent increase in the sinus cycle length in both groups, the increase was significantly less in the neonates than in the adults. In both groups the pacing interval resulting in atrioventricular (AV) nodal Wenckebach was increased significantly by propranolol; however, the increase was again less in the neonates than in the adults. There were comparable dose-dependent increases in atrial and ventricular refractoriness in both neonate and adult groups.

Aging↗

Electrophysiologic and hemodynamic effects of bethanidine sulfate on the immature mammalian heart.

The cumulative electrophysiologic and hemodynamic effects of bethanidine sulfate (2.5, 5, 10 and 15 mg/kg i.v.) were studied in 9 canine neonates and 7 adult dogs. Increased heart rate, blood pressure and enhanced atrioventricular nodal function, observed in both groups, and decreased ventricular refractory periods and inducibility of ventricular arrhythmias seen in the adult, are probably related to a bethanidine-mediated release of catecholamines. However, in spite of the catecholamine release, bethanidine sulfate results in a significant prolongation of atrial refractoriness, this effect being quantitatively more important in the neonate than in the adult.

Aging↗

[Cardiac pacemakers in children. 15 years' experience].

Between 1971 and 1986, 85 pacemakers were implanted at the St Justine Hospital, Montreal, in 57 young patients (25 girls, 32 boys) then aged from one day to 23 years (mean 10.3 years). The patients were followed up for periods ranging from 15 days to 13.5 years (mean 4.5 years); 119 epicardial electrodes were positioned by thoracotomy in 52 patients and by sternotomy in 5 patients; the 85 pacemaker cases were placed in the left retroperitoneal cavity. The pacemakers were programmed in modes VVI (28), AAI (1) and DDD (28). The indications for pacemaker implantation were: complete atrioventricular block in 39 cases (postoperative 16, congenital 22, acquired 1), sinus node disease in 17 cases (postoperative 13, cardiomyopathy 3, normal heart 1) and Romano-Ward syndrome in 1 case. Operated heart diseases which required pacemaker implantation were: D-transposition of the great arteries in 17 cases (complete atrioventricular block 7, sinus node disease 10), tricuspid valve atresia in 3 cases (sinus node disease 3) and tetralogy of Fallot in 3 cases (complete atrioventricular block 3). Twenty-four patients underwent a total of 33 reoperations: 21 changes of battery, 12 changes of electrodes (6 for fibrosis, 6 for breakage). Only one patient developed infection of the pacemaker case. Altogether, the incidence of complications (infection and/or breakage) was low in this series, regardless of the pacing mode. Pacing in children is now an acceptable treatment with low risk provided the indications are well selected.

Adolescent↗

[Indirect evaluation of the effect of 1 alpha-hydroxyvitamin D3 on intestinal absorption of aluminum].

In a former study we have shown that 1 alpha OH vitamin D3 given to hemodialyzed patients taking A1(OH)3 at a constant dose increased their plasma concentrations of aluminium. Two mechanisms can explain this increase: increased intestinal absorption or decreased tissue storage of aluminium. We have, in the present study, given 1 alpha(OH)3 at the same dose (6 micrograms per week) and during the same duration (4 weeks) to 15 stable hemodialyzed patients after aluminium hydroxide has been discontinued 6 weeks before. Under A1(OH)3 treatment mean plasma aluminium was 2.33 +/- 2.36 mumol/l. After A1(OH)3 discontinuation, plasma aluminium decreased significantly as soon as the 2nd week of the control period (1.39 mumol/l). The decrease was maintained in plateau throughout the 5 weeks of the control period (1.38 mumol/l and, the 4 weeks of 1 OH Vit D3 administration (1.40 mumol/l). After 1 alpha OH D3 discontinuation there has been a non significant transient drop of aluminemia followed by a plateau at a level comparable to the previous plateau. Plasma calcium and phosphate concentrations increased significantly with 1 alpha(OH)3 and decreased thereafter confirming biological activity of 1 alpha(OH)3. Since 1 alpha(OH)3 increases plasma aluminium in hemodialyzed patients only when they are taking simultaneously A1(OH)3, it is suggested that this increase is mainly explained by an increase of the intestinal absorption of aluminium.

Adult↗

Starvation-induced alterations of ribosomal protein phosphorylation in Bombyx mori L. Evidence for different phosphorylation kinetics in free and membrane-bound ribosomes.

In the posterior silk gland of Bombyx mori, ribosomal protein S1, homologous to S6 in mammals, is partially phosphorylated in a normally fed animal. Before the first meal of the fifth larval instar, S1 is completely dephosphorylated. Likewise, starvation induces rapid dephosphorylation of the protein in both free and membrane-bound ribosomes. Upon refeeding after 48 h of starvation, S1 becomes phosphorylated again, first on membrane-bound ribosomes, then on free ribosomes, with a lag time of about 3 h. Following 48 h of refeeding, the most highly phosphorylated form of S1 predominates in both populations of ribosomes. These variations in phosphorylation are correlated with the level of protein synthesis in the posterior silk gland, 70% of the ribosomes occurring in polysomes upon feeding and only 30% upon starvation [Prudhomme, J.-C. & Couble, P. (1979) Biochimie (Paris) 61, 215-227]. After in vivo 32P labelling, the phosphopeptides of S1 from free and membrane-bound ribosomes were found to be identical and phosphoserine (only) was found in each S1. These results suggest the involvement of S1 phosphorylation in the regulation of protein synthesis at the translational level and the existence of at least two different pathways controlling this phosphorylation: one for the free ribosomes, the other for the membrane-bound ribosomes.

Animals↗