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Biomedical subjects

M Sauvage

Publications and source records attributed to M Sauvage.

31 records · Page 2Linked to original sources

Systematic use of aprotinin in cardiac surgery: influence on total homologous exposure and hospital cost.

To assess the impact of systematic use of aprotinin, 115 consecutive adults undergoing cardiac surgery were randomly allocated with a sealed envelope technique. Treated (T) patients (n = 58) received 2.10(6) Kallikrein Inactivating Units (KIU) before incision, 2.10(6) prior to bypass, and 5.10(5) KIU.hr-1 for 5 hrs, whereas control (C) cases (n = 57) received nothing. Surgeons, perfusionists, ICU and ward physicians were blinded. Postoperative blood loss decreased from 1198 ml (C) to 698 ml (T) (p less than 0.001). Total transfusional needs were 7.25 (C) and 4.9 (T) units (p less than 0.01), where from 65% were autologous in group T, versus 51% in group C (p less than 0.02). Total homologous exposure decreased from 4.5 (C) to 2.7 (T) units on the average, from 3 to 1 units as a median (p less than 0.01). Multiple Stepwise Regression Analysis showed treatment as the most important variable influencing postoperative blood loss, but duration and type of procedures were more important to explain transfusion needs. Both groups were comparable for other pre- and intra-operative variables. For coronary operations (n = 75), aprotinin showed the strongest negative association with blood loss, the number of arterial conduits being the second influencing variable. No evidence was found for increased early graft thrombosis. The average hospital bill was 9% lower in the treated group, an unexplained finding needing independent confirmation.

Adult↗

Asymmetric distribution of phosphoinositides and phosphatidic acid in the human erythrocyte membrane.

The distribution of phosphoinositides and phosphatidic acid (PA) between the outer and inner layers of the human erythrocyte membrane was investigated by using two complementary methodologies: hydrolysis by phospholipase A2 (PLA2) and immunofluorescence detection with monoclonal antibodies against polyphosphoinositides. The contents of phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 4-phosphate (PIP) and PA were decreased by 15-20% after 60 min incubation with PLA2, while that of phosphatidylinositol (PI) was increased. Studies with 32P-labelled cells revealed that PLA2 treatment led to indirect effects on the metabolism of these phospholipids. Therefore, the asymmetric distribution of phosphoinositides and PA was inferred from the data obtained in ATP-depleted erythrocytes. In these cells with arrested phosphoinositide metabolism, the asymmetric distribution of the major phospholipids was maintained: PLA2 hydrolyzed approx. 20% of PI, PIP2 and PA (but no PIP) indicating their localization in the outer layer of the membrane. This finding was confirmed by immunofluorescence studies with antibodies specific to each phosphoinositide. External addition of anti-PIP2 but not anti-PIP gave a positive reaction both in control and in ATP-depleted erythrocytes. A pretreatment of cells with PLA2 led to a decrease in the intensity of anti-PIP2 staining. These results demonstrate that significant fractions of PIP2, PI and PA are localized on the outer surface of the erythrocyte membrane.

Adenosine Triphosphate↗

Turnover of [14C] sucrose HDL and uptake by organs in the normal or genetically hypercholesterolemic (RICO) rat using a constant infusion method.

The turnover and tissular uptake of HDL (d 1.095-1.21) have been compared in normocholesterolemic or genetically hypercholesterolemic rats by a constant infusion method of [14C] sucrose labelled HDL for 8 h. The HDL clearance rate was not significantly smaller in the RICO than in the normocholesterolemic animal (320 +/- 22 microliters.h-1 versus 366 +/- 24 microliters.h-1 per 100 g of rat). It was the same case for the fractional catabolic rate, respectively equal to 7.8 and 9.4 +/- 0.6%.h-1. For both strains, liver and skeletal muscle were the main catabolic sites for HDL. The HDL uptake rates in intestine or kidney were 3-4-fold smaller than those in the liver. In the RICO rat, intestine, testis and adrenals showed a lesser HDL uptake capacity (expressed per g of organ) than the normocholesterolemic rat.

Animals↗

[Efficacy of a new antisecretory agent (40 749 RP) on human gastric secretion induced by a meal (intragastric titration)].

An antisecretory drug of a new series, 40 749 RP, without anticholinergic or H2 receptor antagonist activities, was tested on meal-induced gastric acid secretion in 6 healthy volunteers. Gastric acid secretion and emptying of liquid were measured using intragastric titration. Oral dosages tested were 1, 2 and 4 mg/kg versus placebo. Inhibitions obtained were dose-related and expressed in percentage of the placebo values: 36 +/- 10 p. 100 for 1 mg/kg; 51 +/- 13 p. 100 for 2 mg/kg and 83 +/- 5 p. 100 for 4 mg/kg. Statistically significant correlation (p less than 0.001) was observed between maximal blood concentration of 40 749 RP and the percentage of secretory inhibition during the 90 min of the test. No change in gastrin response or in gastric emptying was observed whatever the dose.

Adult↗

Ranitidine upon meal-induced gastric secretion: oral pharmacokinetics and plasma concentration effect relationships.

1 Ranitidine oral kinetics and plasma concentration-effect relationships upon meal-induced gastric secretion were investigated in normal subjects. Four oral doses of ranitidine (50, 100, 150 or 200 mg) and placebo were tested. 2 Oral ranitidine showed a terminal half-life of about 2 h 25 min. Maximal plasma level was about 240 ng/ml for a 100 mg dose, and occurred about 1 h after dose. From the range of 50 to 200 mg dose, no indication of non-linearity was observed in the drug kinetics. 3 Ranitidine administration resulted in a dose-related reduction in meal-stimulated acid secretion reaching, 46, 70, 82 and 92%, respectively. Mean ranitidine plasma concentrations producing 50 and 80% inhibition of acid secretion were 73 and 180 ng/ml, respectively, with great inter-individual variability. 150 and 200 mg ranitidine oral doses maintained IC50 for at least 4.5 and 5.5 h, respectively. Upon oral administration, ranitidine exerted no effect on gastric emptying of the meal but slightly decreased the gastrin response to the meal.

Adult↗

[Effect of a liquid protein meal on acid secretion, gastric emptying and serum gastrin before and after fundic vagotomy for duodenal ulcer].

Using a technique adapted from the intragastric titration method of Fordtran and Walsh, food-stimulated acid secretion, gastrin release and gastric emptying have been investigated before and after proximal vagotomy in 11 duodenal ulcer patients. Vagal denervation of the proximal stomach resulted in (i) a 40 p. 100 decrease in acid secretion in response to a protein meal; this response was of the same magnitude as the reduction in pentagastrin-stimulated acid output, (ii) a marked increase in food-induced gastrin release, suggesting a relationship between antral gastrin release and fundal vagal innervation since antral pH remained constant and the amount of protein and the distension volume within the antrum were the same as before proximal vagotomy, (iii) a slowing down of the initial phase of gastric emptying of the liquid protein meal in 5 patients, a slight acceleration in 4 and no change in 2. The clinical relevance of these findings is discussed.

Adult↗

Effects of the monoamine oxidase A inhibitor moclobemide on hippocampal plasticity in GR-impaired transgenic mice.

A reduction in glucocorticoid receptor (GR) function leads to hippocampus-dependent allocentric spatial learning deficits, altered novelty exploration and disrupted hippocampal long-term potentiation (LTP) in transgenic mice expressing a GR antisense construct. After continuous long-term treatment of these mice with moclobemide (a reversible inhibitor of monoamine oxidase A), spatial navigation performance but not accuracy improved during initial acquisition. These changes were associated with a shift of the threshold for the induction of hippocampal LTP at low stimulation frequencies. Moreover, novel object exploration increased in both control and transgenic animals following long-term treatment with moclobemide. These findings open the possibility that antidepressants might improve hippocampal function under conditions of impaired stress hormone regulation, and that these drugs might in part act through this mechanism to attenuate cognitive deficiency in disorders such as depression.

Animals↗

Aortic elastin and collagen content and synthesis in two strains of rats with different susceptibilities to rupture of the internal elastic lamina.

We have previously characterized two normotensive strains of rats which differ markedly in their susceptibility to spontaneous rupture of the internal elastic lamina (IEL), the Brown Norway (BN) being very susceptible and the Long Evans (LE) being resistant. Here we quantified biochemically the elastin and collagen content of aortae from adult male BN and LE rats aged 12, 18 and 22 weeks and showed that the elastin content was lower and the collagen content higher in the BN strain than in the LE strain, resulting in a markedly lower elastin/collagen ratio in the former strain. These modifications were present both in the thoracic aorta, which is devoid of IEL ruptures, and in the abdominal segment where ruptures frequently occur in the BN rat, suggesting that they could represent a predisposing factor in the presence of other local factors. Quantifications of relevant mRNAs in aortae of younger male BN and LE rats by Northern blot showed that there are lower tropoelastin transcript levels in the BN rat at 6 weeks in both thoracic and abdominal segments than in the age-matched LE rat. In contrast there was no consistent interstrain difference in alpha 1 type I collagen transcripts and alpha 1 type III collagen transcripts were higher in the BN aorta only at 6 weeks in the abdominal segment. We conclude that the BN rat presents an aortic elastin deficit which appears to be in part explained by a decreased elastin synthesis in young, growing rats and may be genetically determined. However, a direct relation of this elastin deficit with susceptibility to rupture of the IEL cannot be concluded from this study.

Animals↗