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Biomedical subjects

M Couturier

Publications and source records attributed to M Couturier.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effect of vitamin E on 2-deoxy-D-glucose uptake in human fibroblast cultures.

2-Deoxy-D-glucose (2-DOG) uptake was tested in human fibroblast cultures in the presence and absence of vitamin E. Addition of 10 micrograms/ml vitamin E to the culture medium significantly reduced this uptake for 2-DOG concentrations of 0.005 to 10 mmol/liter (P less than or equal to 0.01). The decrease of 2-DOG uptake was inversely proportional to the rise in 2-DOG concentration (P less than or equal to 0.01). The presence of vitamin E reduced by 71% the average cellular level of lipid peroxides (expressed as thiobarbituric acid reactive substances) and caused a small but significant decrease in the cholesterol concentration (P less than or equal to 0.01). These last results might explain the decrease in 2-DOG uptake observed in the presence of vitamin E.

Biological Transport↗
PubMed1990

Vitamin E deficiency and lipoperoxidation during adult respiratory distress syndrome.

Vitamin E (Vit E) is an important component of the lung's defense against oxidant injury. The aim of this study was to determine a) if adult respiratory distress syndrome (ARDS) was associated with a decrease in Vit E plasma level linked to an enhancement of plasma lipoperoxidation, and b) if this Vit E deficiency might be explained by malnutrition and/or a consumption defect. Vit E, lipoperoxides (LP), total lipids, and fatty acid plasma levels were measured in 12 patients with ARDS (PaO2 less than or equal to 60 Torr with FIO2 0.6 on mechanical ventilation). At the onset of ARDS (T0), the decrease in Vit E plasma level was significant (p less than .001) 7.73 +/- 0.54 (n = 12) vs. 11.46 +/- 0.55 mg/L (n = 7) in the control group (healthy subjects breathing room air). A significant (p less than .05) increase in LP was simultaneously observed (4.12 +/- 0.35 [n = 12] vs. 2.94 +/- 0.30 nmol/ml [n = 17]) in the control group. At T0, LP were inversely correlated with Vit E plasma levels (r = .78, p less than .01). Vit E deficiency was associated with low levels of total plasma lipids (3.68 +/- 0.25 g/L) and plasma cholesterol (0.97 +/- 0.07 g/L). Thus, the Vit E/total lipids ratio (2.18 +/- 0.17 mg/g) was always above the accepted normal limit value for this ratio (0.8 mg/g).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Prevalence of four enterotoxin (STaP, STaH, STb, and LT) and four adhesin subunit (K99, K88, 987P, and F41) genes among Escherichia coli isolates from cattle.

Colony hybridizations with DNA probes for 3 heat-stable (STaP, STaH, and STb) enterotoxins and 1 heat-labile (LT) enterotoxin and for 4 adhesins (K99, F41, K88, 987P) were performed on 870 Escherichia coli isolates to determine pathotypes prevalent among enterotoxigenic E coli (ETEC) isolated from cattle in Belgium. One hundred thirty-two E coli isolates (15.2%) hybridized with probes STaP, K99, and/or F41. The 5 other probes were not hybridized by E coli isolates. Therefore, only STaP enterotoxin and K99 and F41 adhesins were virulence factors of ETEC isolated from cattle. Two major pathotypes accounted for 95% of the ETEC: STaP+K99+F41+ (67.4%) and STaP+K99+ (27.3%). The last 5% of probe-positive isolates had STaP+, STaP+F41+, or K99+F41+ minor pathotypes. Of 12 American ETEC isolates also assayed, 7 were positive with STb and/or 987P probes (pathotypes STaP+STb+, STaP+ 987P+, or STaP+STb+987P+) and may be porcine- rather than bovine-specific enteropathogens. The remaining 5 American ETEC isolates belonged to 3 minor pathotypes (STaP+, STaP+F41+, and K99+F41+) also found among Belgian E coli isolates. Such isolates may be derivatives of STaP+K99+F41+ or STaP+K99+ ETEC after in vivo or in vitro loss of virulence genes and/or non-ETEC isolates, which have acquired virulence genes by in vivo transfer.

Adhesins, Escherichia coli↗
PubMed1989

[Antibiotic resistance plasmids from Serratia marcescens and their elimination by DNA-gyrase inhibitors].

We studied the effects of ciprofloxacin on 73 strains of Serratia marcescens. In the first place, we have tested their plasmidic content: 76% of Serratia marcescens strains contained plasmids by electrophoresis, and 29% of these plasmids were self-transmissible by conjugation. Secondly, we studied the plasmid stability with regard to ciprofloxacin. We obtained a spontaneous cure with 19% of plasmids, and ciprofloxacin, at very low concentrations (0.4 mg/l), increased the rate of cure and more efficiently than novobiocin, a compound used as a known curing agent.

Bacterial Typing Techniques↗
PubMed1988

Short- and long-term vitamin A treatment in children with cholestasis.

Newborns have limited reserve supplies of vitamin A. Infants with chronic cholestasis are in a precarious nutritional state because of their limited ability to build these stores even though the vitamin is present in their diet. In this study, we investigated liver concentrations of vitamin A in 30 children with extrahepatic biliary atresia. We demonstrate that correction of the deficiency occurs after intramuscular administration of a water-miscible solution of retinyl palmitate (100,000 IU, or 30 mg retinol equivalent). Furthermore, we evaluated the effect of vitamin A injections on liver and blood concentrations in nine children with chronic cholestasis over a 1-y period. We conclude this treatment is efficient and is well tolerated.

Biliary Atresia↗
PubMed1987

Comparative use of glucose and fructose in cultured fibroblasts from patients with hereditary fructose intolerance.

The utilization of fructose and glucose by fibroblast cultures obtained from patients with hereditary fructose intolerance (HFI) was studied in comparison with fibroblast controls. The cell growth, the time course of D-glucose or D-fructose uptake and the consumption of fructose were similar for both HFI and control cells. Some results showed significant differences between these two cell types: HFI cells consumed less glucose, produced less lactate and contained less glycogen than control cells. Furthermore, significantly less [U-14C]D-glucose and [U-14C]D-fructose was incorporated into lipids in HFI cells than in control cells. The mechanisms responsible for these differences observed between the two cell types are not known.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1987

Comparative metabolic effects of fructose and glucose in human fibroblast cultures.

The comparative metabolic effects of fructose and glucose were determined in human fibroblast cultures. Cells were grown in four different media containing 5.5 and 27.5 mM of glucose and fructose, respectively. For these two hexoses, we compared their uptake, consumption, and conversion into 14CO2 and 14C-lipids. D-Fructose was taken up in fibroblasts by an unsaturable process and its consumption was much smaller than that of D-glucose. Whatever the experimental procedure, the glycogen content of cells grown in fructose media was significantly lower than of those grown in glucose media. Labeling of fructose and glucose with 14C showed that more carbon from fructose than from glucose was incorporated into CO2 and glycerolipids. The relative distribution of 14C in the different lipid fractions was similar for both hexoses. These results indicated that the pathways of intermediary metabolism in fibroblast cultures were influenced by the nature of the carbohydrate present in the culture medium and that fructose was a better lipogenic substrate than glucose in human fibroblast cultures.

Carbon Dioxide↗
PubMed1987

Plasma lipid peroxides in cholestatic children.

Plasma lipid peroxide levels were studied in 40 children with chronic cholestasis comprising 21 with syndromatic paucity of interlobular bile ducts (PILBD) and 19 with biliary atresia. Compared to the controls, mean lipid peroxide values were twice as high in children with biliary atresia (4.56 +/- 2.28 nmol/ml) and four times as high in those with PILBD (9.62 +/- 3.3 nmol/ml). These differences are highly significant. In patients with biliary atresia, the increase in lipid peroxide levels was clearly related to the bilirubin, cholesterol and phospholipid concentrations. In the PILBD group, however, there was little evidence of such a relationship. Vitamin E treatment seemed to have no effect on these increased lipid peroxide levels during the evolution of chronic cholestasis, and further investigations are necessary to clarify the pathological mechanisms involved.

Adolescent↗
PubMed1986

Mini-F E protein: the carboxy-terminal end is essential for E gene repression and mini-F copy number control.

Mini-F is a segment of the conjugative plasmid F consisting of two origins of replication flanked by regulatory regions, which ensure a normal control of replication and partitioning. Adjacent to the ori-2 origin is a complex coding region that consists of the E gene overlapped by three open reading frames with the coding potential for 9000 Mr polypeptides here designated 9 kd-1, 9 kd-2 and 9 kd-3. In this paper, we show that open reading frame 9 kd-3 is preceded by active promoter and Shine-Dalgarno sequences. The E coding region specifies: an initiator of replication, which acts at the ori-2 site; a function that negatively regulates the expression of the E gene; and a function involved in mini-F copy number control. To assign one of these functions to one of the overlapping coding sequence, we have isolated, characterized and sequenced mutations mapping in the E coding region. In this paper, we analyse two mutations (cop5 and pla25) that abolish the repression of the E gene. As these mutations affect the primary structure of protein E itself but not the 9 kd polypeptides, we conclude that protein E takes part in the negative regulation of its own synthesis. In addition, the localization of the cop5 and pla25 mutations indicates that the carboxy-terminal end of the E protein is involved in the autorepression function. The cop5 mutation causes an eightfold increase of the mini-F copy number. The pla25 mutation leads to the inability of the derived mini-F plasmid to give rise to plasmid-harbouring bacteria. The ways in which the cop5 and pla25 mutations may lead to such phenotypes are discussed in relation to the different functions mapping in the E coding sequence.

Amino Acid Sequence↗
PubMed1986

Effects of postoperative cholestyramine and phenobarbital administration on bile flow restoration in infants with extrahepatic biliary atresia.

Surgical restoration of bile flow in patients with extrahepatic biliary atresia (EHBA) results in the disappearance of clinical cholestasis in about 30% of cases. It is suggested that early postoperative administration of phenobarbital (PB) or cholestyramine (Ch) may improve this percentage. Eighty patients were randomly divided into three subgroups comprising 27 who were treated with Ch (4 g/d), 27 who were given PB (7.5 to 10 mg/kg/d) during the first 3 postoperative months and 26 untreated patients, who served as controls. Cholestasis was observed to disappear in 38 (group I) patients and to persist in 42 (group II) patients, as judged from their total blood bilirubin levels, the conjugated/total bilirubin ratio, measurements of cholesterol, bile acids and alkaline phosphatase, and of Rose Bengal fecal excretion. Neither Ch nor PB significantly improved the degree or duration of cholestasis in either group.

Barbiturates↗
PubMed1986

[Tamponade and total parenteral nutrition by central venous catheter].

Various complications are associated with the use of central venous catheters for total parenteral nutrition; cardiac tamponade is one of the most severe. Four cases are reported of cardiac tamponade during total parenteral nutrition: three of them were related to cardiac perforation by the tip of the catheter, placed in the right atrium; the fourth case may have been due to cardiac perforation or to an extraintestinal complication of inflammatory bowel disease. Hydropericardium may manifest itself soon after the catheter is inserted or, more usually, some days or weeks later. Immediate diagnosis is mandatory: a sudden and unexpected deterioration in a patient receiving total parenteral nutrition through a central venous catheter, with shock, heart failure, cyanosis, congestion of neck veins should arouse suspicion of hydropericardium. Long term undernutrition, a small atrophic heart, steroid treatment may also contribute to cardiac perforation. Immediate aspiration of the hydropericardium may be life-saving: if possible, the fluid is evacuated through the catheter while still in place; otherwise, pericardiocentesis must be immediately performed. Such complications can be prevented by: the use of flexible silicone or polyurethane catheters instead of rigid polyethylene catheters, especially for long term use; a correct positioning of the catheter tip in the superior vena cava in its extrapericardial sector, as it can be checked by chest X-ray. This examination, with opacification of the catheter with contrast medium, must be repeated because of the possibility of secondary displacement of the catheter.

Adult↗
PubMed1985

Hybridization on bovine enterotoxigenic Escherichia coli with two heat-stable enterotoxin gene probes.

Hybridizations were done on bovine enterotoxigenic Escherichia coli with 2 heat-stable (ST) enterotoxin gene probes from porcine and human origin (STp and STh). Of the baby mouse-positive isolates, 56 (53%) hybridized the STp probe and 50 (47%) did not. There was no isolate that hybridized the STh probe. Hybridization with the Stp probe was more frequent (P less than 0.005) for E coli isolated from calves that died before 2 weeks of age (49 STp-positive isolates of 77 [64%] isolates) than for E coli isolated from calves that died after 2 weeks of age (2 STp-positive of 21 [10%] isolates).

Animals↗
PubMed1984

Comparative use of fructose and glucose in human liver and fibroblastic cell cultures.

The effect of fructose as a substitute for glucose in cell culture media was investigated in human skin fibroblast and liver cell cultures. Cells were grown for between 2 and 10 days in identical flasks in four different media, containing 5.5 mmol X 1-1 and 27.5 mmol X 1-1 glucose and fructose, respectively. In the presence of fructose, cell growth was stimulated, but less in liver cells than fibroblasts. At Day 6, increases were observed in [3H]thymidine incorporation, protein levels, and amino acid consumption, and a reduction was noted in ATP levels. In media containing 5.5 mmol X 1-1 glucose or fructose, consumption of fructose was four times lower than that of glucose at Day 3 and did not rise until Day 6. In fructose media, the lactate production was very low (four to five times less than that of glucose) and the pH values were always higher. Some findings were different for the fibroblasts and liver cells, owing to the specific characteristics of these two cell types in culture; this applied especially to the effects of glucose and fructose concentrations of 27.5 mmol X 1-1. Several possible explanations for the stimulation of cell growth in fructose medium were discussed.

Adenosine Triphosphate↗