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Biomedical subjects

F Bourgeois

Publications and source records attributed to F Bourgeois.

At least 37 records · Page 2Linked to original sources

[Comparative in vitro activity of glycopeptides against coagulase negative staphylococci isolated in pediatric hospital units].

The minimum inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined for 32 coagulase-negative staphylococci strains recovered from blood specimens from pediatric intensive care patients. All the strains were susceptible to vancomycin (MIC less than 4 mg/l). Sixteen strains were susceptible to teicoplanin (MIC less than 4 mg/l) and the sixteen remaining strains exhibited intermediate susceptibility, with MICs of 8 mg/l (10 strains) or 16 mg/l (6 strains). Inhibition zone diameters seen with vancomycin during agar diffusion susceptibility testing were consistently greater than 17 mm. Inhibition zones obtained with teicoplanin were 17 mm or more in diameter for 30 strains and under 17 mm in diameter for 2 strains. For 14 strains (44%), agar diffusion testing failed to detect the decreased susceptibility to teicoplanin revealed by MIC determinations. The agar diffusion method does not seem reliable for the determination of in vitro susceptibility to teicoplanin.

Anti-Bacterial Agents

Denaturing gradient gel electrophoresis for rapid detection of latent carriers of a subtype of acute intermittent porphyria with normal erythrocyte porphobilinogen deaminase activity.

Acute intermittent porphyria is an autosomal dominant disorder defined by a partial deficiency of porphobilinogen deaminase (EC 4.3.1.8). Clinical manifestations of the disease are characterized by acute attacks of neurological dysfunction often linked to environmental factors. Early diagnosis of gene carriers is important in the prevention of attacks and is usually achieved by determining the porphobilinogen deaminase activity in erythrocytes. However, in a subtype of acute intermittent porphyria, the enzymatic defect is restricted to nonerythropoietic cells. Different mutations have already been described that account for this phenotype in two unrelated families. We previously detected asymptomatic carriers by using mutation-specific probes after in vitro amplification of the target DNA sequence. In this study, we investigated the DNA of eight unrelated subjects with the same subtype of acute intermittent porphyria by using the polymerase chain reaction, with subsequent analysis of the amplified products by denaturing gradient gel electrophoresis. Five of these patients shared the same single-base change. This technique was quite simple and efficient for detecting asymptomatic carriers. Importantly, it is potentially useful for studying families with the same phenotypic subtype of the disease and possibly different mutations in the same DNA region.

Base Sequence

Bactericidal activity of daptomycin against vancomycin-resistant Enterococcus faecium in an in vitro pharmacokinetic model.

A dynamic in vitro model was used to determine the killing kinetics of daptomycin against 15 vancomycin-resistant clinical isolates of Enterococcus faecium. Concentration profiles simulating those observed in serum following administration of both low-dose (2 mg/kg) and high-dose (6 mg/kg) daptomycin were bactericidal within 5.5 and 2.8 h, respectively. In contrast, when albumin was added to the growth medium, the corresponding bacterial killing times were slowed to greater than 24 h and 7 h; these results suggest that in the clinical setting, daptomycin dosages of approximately 6 mg/kg are required to achieve bactericidal activity against vancomycin-resistant Enterococcus faecium.

Albumins

Reproducibility of monoamine metabolite measurements in human cerebrospinal fluid.

The levels of homovanillic acid (HVA), 5-hydroxy indoleacetic acid (5HIAA), and 3-methoxy-4-hydroxy phenylglycol (MHPG) were determined in the cerebrospinal fluid (CSF) of 28 patients with cognitive disorders on Day 1 and Days 8 or 15. During that period all patients were kept hospitalized under strict standard conditions, did not develop any acute CNS lesion, had no changes in their treatment and no acute systemic disease. The mean levels found in the first and second determinations were almost identical for the 3 metabolites; respectively 37.8 ng/ml and 36.3 ng/ml for HVA, 27.8 ng/ml and 27.9 ng/ml for 5HIAA, and 12.9 ng/ml and 12.3 ng/ml for MHPG. Thus, the mean values of these metabolites in CSF are reproducible at least during a 15-day hospitalization. However statistically significant individual changes in metabolite levels were found between the two samples in 82% of patients for HVA, 32% for HIAA and 48% for MHPG. The number of patients required to detect a significant change in the mean levels of each monoamine metabolite has been calculated taking into account the extent of intraindividual variations.

Adult

[In vitro comparative activity of five macrolides against 190 Branhamella catarrhalis strains].

We compared the in vitro activity of 5 macrolides against 190 strains of Branhamella catarrhalis; 48 strains were isolated at Centre Hospitalier, Aix-en-Provence, the 142 others were isolated during 1987, in 15 different Centres-Hospitaliers-Généraux in France. 153 strains were betalactamase producing strains; no difference in susceptibility to erythromycin was observed on betalactamase producing and non producing strains. Three active macrolides against 100% of strains were: erythromycin (MIC 50 = 0.25 mg/l - MIC 90 = 0.50 mg/l), roxithromycin (MIC 50 = 0.50 mg/l - MIC 90 = 0.50 mg/l) and josamycin (MIC 50 = 0.50 mg/l - MIC 90 = 1 mg/l); A lower activity was noted on midecamycin (mic 50 = 2 mg/l - MIC 90 = 2 mg/l) and spiramycin (MIC 50 = 4 mg/l - MIC 90 = 8 mg/l).

Carbon Dioxide

[Neonatology and maternal post-partum depression. Applications in the prevention of disturbances early interactions].

From an epidemiological study of post-partum maternal depression, the authors have identified several risk factors which have to be taken in account in order to establish preventive measures. The early separation of the mother and her neonate is a stressful event. The "hostile" form of post-partum depression must be recognized as such; it can be misinterpreted, and may result in rejection of the mother by the hospital staff. Team-work is therefore necessary so that this particular attitude can be recognized and understood, and that at-risk-mothers may be correctly taken care of, thus preventing resulting interactional disturbances and child abuse. Some mothers refuse treatment proposals, which may have serious consequences for the child. In maternal depression, a rapid intervention by the mothering delegation may lead to a "psychological abduction" of the child and subsequent difficulties in mother-child relationship. The authors emphasize the need for early detection and treatment of puerperal maternal difficulties in order to prevent disturbances in infant-mother interactions.

Adult

Serum lipoprotein and apolipoprotein profiles of the genetically obese ob/ob mouse.

The lipid transport system of 3-month-old male C57BL/6J obese (ob/ob) mice was investigated. Serum lipoproteins were separated by density gradient ultracentrifugation and characterized by their chemical and electrophoretic properties as well as their relative apolipoprotein contents, defined according to molecular weight and charge. Obese, ob/ob mice exhibited a marked hyperlipoproteinemia resulting from large increases in low-density lipoproteins (LDL, d 1.021-1.058 g/ml) and high-density lipoproteins (HDL, d 1.058-1.137 g/ml), particularly, the HDL2 subclass (d 1.058-1.109 g/ml). This increase in lipoproteins was entirely responsible for their hypercholesterolemia and hyperphospholipidemia. By contrast, these obese mice had a net decrease in very-low-density lipoproteins (VLDL, d less than 1.016 g/ml) and intermediate-density lipoproteins (IDL, d 1.016-1.021 g/ml), which accounted for their moderate hypotriglyceridemia. The chemical composition of heterogeneous light LDL (d 1.021-1.040 g/ml and dense LDL (d 1.040-1.058 g/ml) overlapped by HDL-like particles was highly modified. These modifications consisted of increases in the percentages of cholesteryl ester and phospholipid and decreases in that of triacylglycerol. There were also marked changes in the relative values of the apolipoproteins of VLDL, but principally, IDL and LDL. IDL and light LDL were poorer in apolipoproteins BH (Mr 340,000-320,000) and eventually in apolipoprotein BL (Mr 220,000-200,000) and enriched in apolipoproteins E (Mr 37,000-35,000) and C-A-II (Mr approximately equal to 12,000). A similar and very significant change occurred in VLDL for both the apolipoproteins BL and C-A-II. Dense LDL, mainly poorer in apolipoprotein BH and enriched in apolipoprotein A-I (Mr 28,000-27,000), closely resembled HDL2 in all the groups, and were enriched in apolipoproteins C-A-II in only the obese mice. We suggest that ob/ob mice are probably protected against atheromata because of the low VLDL and IDL levels, and the increase in HDL2.

Adipose Tissue

Serum lipoprotein profiles in mice: effects of early over- and undernutrition.

Effects of early over- and undernutrition on lipoprotein profiles of adult Swiss male mice reared in litters of different sizes were investigated. Lipoproteins were isolated by density gradient ultracentrifugation and defined by chemical composition. Protein moieties were defined by their changes. The lipoprotein lipase (LPL) activity in epididymal adipose tissue, heart and diaphragm was measured. Early feeding patterns induced permanent body weight differences in adult mice. Serum phospholipid content was significantly higher in obese than in control mice. Overfeeding led to significantly higher activity of LPL in adipose tissue; inversely, undernutrition induced a lower LPL activity. There was a trend toward variations of lipoprotein concentrations in relation to litter size, with significant differences being observed only between obese and undernourished mice for LDL-HDL1 (low density lipoprotein--high density lipoprotein) and HDL2 concentrations. Compared with normally fed mice the most notable alterations in plasma lipoprotein composition were, in LDL-HDL1, greater cholesteryl ester in obese and less phospholipid in undernourished mice. In contrast, tetramethylurea-soluble apolipoprotein distribution was unaffected by litter size. Although moderate differences were observed in lipoprotein compositions and levels in over- or undernourished mice, further investigations of lipoprotein metabolism and metabolic abnormalities in this animal model are required.

Adipose Tissue

In vivo animal demonstration of the effect of vasoactive drugs using 195mAu and gamma camera techniques.

195mAu, an ultrashort-lived (physical half life = 30.5 s) generator-produced radionuclide, has been used in an animal model to study, by gamma camera techniques, the peripheral effects of the vasoactive drugs norepinephrine and sodium nitroprusside systemically administered or epinephrine (intraarterially) injected at various concentrations. According to the results obtained by the analysis of time activity curves generated from areas of interest drawn on the proximal and distal parts of the limbs, the well known hemodynamic changes induced by these drugs, vasoconstriction (resulting in a decrease of the distal activity recorded), or vasodilatation (shortening the time of radioactivity appearance), could be observed. It is concluded that gamma camera techniques using the ultrashort lived radionuclide 195mAu allow the in vivo study of the effects of vasoactive drugs in an animal model and potentially in clinical situations.

Animals

[Action of ifenprodil tartrate in obliterative arteriopathies of the lower limbs. Combined studies using proximal blood flow and distal transcutaneous oxygen pressure].

A simultaneous analysis of both the variations of the flow in the stenosis artery and the distal PO2, was carried out during an injection of an alpha-blocker: the Tartrate d'Ifenprodil, on twenty-five patients afflicted with occlusive disease of the lower limbs requiring surgery. The measurements were taken under general anaesthesia, before any surgical operation, the hemodynamic and ventilatory balance being monitored by radial manometry and arterial gas analysis. We observe an increase of proximal arterial flow and at the same time an improvement of the distal TcPO2. Moreover, the variations of microcirculation flow measured by TcPO2 are correlated with proximal flow variations, this relation: delta TcPO2 = K delta Q + A is more true in the first and the second stages of Fontaine. With the same (Tartrate d'Ifenprodil) posology, the distal benefit measured by transcutaneous oximetry is less important in advanced stages compared with other stages (everything else being equal). The transcutaneous measurement of the distal oxygen pressure, allows an objective view of microcirculatory improvement obtained by a vasoactive substance (ifenprodil tartrate) considering the specific nature of each patient arteriopathy.

Adult

Lipogenesis in primary cultures of adipoblasts derived from genetically obese Zucker rats.

Adipocyte precursor cultures prepared from the epididymal fat pads of genetically obese (fa/fa) and lean (Fa/Fa) Zucker rats grow similarly in culture. Addition of enriched medium (EM) containing human serum, insulin, and glucose stimulated lipid filling of the adipocyte precursors in both cultures. However, [3H] H2O incorporation into total lipids, fatty acid synthetase and lipoprotein lipase activities, and cytosolic protein contents are all decreased in the fa/fa compared with the Fa/Fa cultures. Substitution of lean or obese rat serum for human serum in the enriched medium does not alter the decreased lipogenic capacity of the fa/fa adipocyte precursor cultures.

Adipose Tissue

Dietary-induced obesity: effect of dietary fats on adipose tissue cellularity in mice.

1. Male and female mice, 4 weeks old, were fed ad lib. diets containing various amounts of lard (0-300 g/kg) or various kinds of dietary fats (300 g/kg) for 13 weeks. Fat cell number and size were determined by a histological method in three different adipose sites. 2. Lard at 200 g/kg diet (43% energy from lipids) was sufficient to promote fat cell hyperplasia in the parametrial fat. Hyperplasia was also observed in the subcutaneous fat in males. The relationship between fat cell hypertrophy and the level of lard in the diet was dependent on site and sex. 3. Obesity was produced whatever the kind of dietary fat eaten: lard, beef tallow, sunflower oil or soya-bean oil. In the subcutaneous depot of males given lard, fat cell size and number were increased, but only cell hypertrophy was observed in those given soya-bean oil. In the female groups of mice fat cell hyperplasia or hypertrophy or both were related to the adipose site but not the kind of dietary fat. 4. It is concluded that dietary fats of different origin can induce obesity in mice. The effects on adipose tissue cellularity depend on the levels and kind of fat eaten, the adipose site and sex.

Adipose Tissue

Early cholesterol feeding: are there long-term effects in the rat?

The effects of exposure to cholesterol in early life on diet-induced hypercholesterolemia in adult rats were investigated. Experiment 1: dams and their offspring received either a control or a cholesterol-enriched diet during gestation and lactation; at 7 weeks of age half of the rats fed each diet were switched to the other diet for 50 weeks. Experiment 2: adult males 6 months old were fed one of the 2 experimental diets for 10 weeks, at which time half of the rats in each group were switched to the other diet for 50 weeks. Cholesterol, triglycerides and phospholipids were determined in liver, serum, heart and aorta at different ages. In both experiments, feeding a cholesterol-enriched diet induced an increase in serum and liver cholesterol and triglyceride levels, but serum phospholipid levels were not influenced by diet. The cholesterol-enriched diet induced a decrease in liver phospholipid levels. Old rats (experiment 2) fed the cholesterol-enriched diet exhibited higher heart cholesterol level than controls. In experiment 1 rats fed the cholesterol-enriched diet in early life and thereafter had lower heart triglyceride levels than the 3 other groups and lower liver triglyceride levels that rats fed control diet in early life and cholesterol diet at 7 weeks. In both experiments, cholesterolemia was not influenced by the diet fed at the beginning of the test. The results indicate that cholesterol given in early life does not protect against diet-induced hypercholesterolemia in adult rats.

Aging