Search PubMed⌕ Search

Biomedical subjects

T Lefebvre

Publications and source records attributed to T Lefebvre.

At least 19 recordsLinked to original sources
PubMed2001

Identification of N-acetyl-d-glucosamine-specific lectins from rat liver cytosolic and nuclear compartments as heat-shock proteins.

Cytosolic and nuclear O-linked N-acetylglucosaminylation has been proposed to be involved in the nuclear transport of cytosolic proteins. We have isolated nuclear and cytosolic N-acetyl-d-glucosamine (GlcNAc)-specific lectins from adult rat liver by affinity chromatography on immobilized GlcNAc and identified these lectins, by a proteomic approach, as belonging to the heat-shock protein (HSP)-70 family (one of them being heat-shock cognate 70 stress protein). Two-dimensional electrophoresis indicated that the HSP-70 fraction contained three equally abundant proteins with molecular masses of 70, 65 and 55 kDa. The p70 and p65 proteins are phosphorylated and are themselves O-linked GlcNAc (O-GlcNAc)-modified. The HSP-70 associated into high molecular mass complexes that dissociated in the presence of reductive and chaotropic agents. The lectin(s) present in this complex was (were) able to recognize cytosolic and nuclear ligands, which have been isolated using wheat germ agglutinin affinity chromatography. These ligands are O-GlcNAc glycosylated as demonstrated by [(3)H]galactose incorporation and analysis of the products released by reductive beta-elimination. The isolated lectins specifically recognized ligands present in both the cytosol and the nucleus of human resting lymphocytes. These results demonstrated the existence of endogenous GlcNAc-specific lectins, identified as HSP-70 proteins, which could act as a shuttle for the nucleo-cytoplasmic transport of O-GlcNAc glycoproteins between the cytosol and the nucleus.

Acetylglucosamine↗
PubMed2001

[Filmstrips and public health].

In this article, the author presents an abandoned audiovisual technique: the "filmstrip". He is interested in connections between this technique and the health service, and more particularly in filmstrips produced by the "Sécurité sociale" in France.

Audiovisual Aids↗
PubMed2000

O-glycan variability of egg-jelly mucins from Xenopus laevis: characterization of four phenotypes that differ by the terminal glycosylation of their mucins.

Eggs from Xenopus laevis are surrounded by several layers of jelly that are needed for proper fertilization. Jelly coat is composed of high-molecular-mass glycoconjugates to which are bound many globular proteins. O-glycans released from the jelly coat of X. laevis have been partially described in previous studies. In this study, we compared the glycosylation pattern of the egg jelly coat isolated from six specimens of X. laevis. The O-glycans were released from jelly coats by alkali/borohydride treatment. Structural characterization was performed through a combination of one- and two-dimensional (1)H-NMR and methylation analysis. This allowed the description of a new family of sulphated O-glycans present in jelly coats of all X. laevis. However, the jelly O-glycans showed a low extent of polymorphism between specimens. This intra-specific variability was restricted to the terminal substitution of O-linked oligosaccharides. The differential expression of two glycosyltransferase [an alpha-(1-->4) galactosyltransferase and an alpha-(1-->3) fucosyltransferase] activities resulted in the characterization of four phenotypes of X. laevis. Furthermore, electrophoretic analysis suggested that the high-molecular-mass fraction of jelly coat was mostly composed of mucin-type glycoproteins. Blot analysis with lectins confirmed that the glycan variability was borne by these mucin-type components. However, fertilization assays suggested that the glycan polymorphism had no repercussion on egg fertilizability.

Animals↗
PubMed1999

Effect of okadaic acid on O-linked N-acetylglucosamine levels in a neuroblastoma cell line.

O-Linked N-Acetylglucosamine (O-GlcNAc) is a major form of post-translational modification found in nuclear and cytoplasmic proteins. Several authors have advanced the hypothesis according to which phosphorylation and O-GlcNAc glycosylation are reciprocally related to one another [1,2]. In order to test this hypothesis we have investigated the effect of a broad spectrum phosphatase inhibitor, okadaic acid (OA), generally used to induce protein hyperphosphorylation, on the GlcNAc content of cellular glycoproteins. We demonstrate that in neuronal cells lines OA decreases the level of O-GlcNAc in both nuclear and cytoplasmic proteins with a greater effect in the nuclear fraction. This phenomenon was demonstrated by the use of three different procedures for the detection of O-GlcNAc in conjunction with a systematic treatment with PNGase F. O-Linked GlcNAc was characterized using respectively lectin staining with WGA, galactosyltransferase labeling and metabolic labeling of cultured cells with [3H]glucosamine. Although the effects on individual proteins varied, a less pronounced effect was observed on HeLa or COS cell total homogenates. When Kelly cells were treated with OA, the major observation was a decrease in O-GlcNAc content of nuclear proteins. The measurement of the UDP-GlcNAc level clearly demonstrates that the decrease on the O-GlcNAc level in the neuroblastoma cell line after treatment with okadaic acid is not a consequence of the modification of the UDP-GlcNAc pool.

Acetylglucosamine↗
PubMed1999

[A campaign against quackery in the 20s].

During the 20's, La Vie saine, popular journal of the Comite national de defense contre la tuberculose (France), campaigned against quackery. In this purpose, the journal tried to educate people and denounce quackers.

Communicable Disease Control↗
PubMed1994

[The inventive genius of pharmacists: invention patents 1836-1852].

The author calls attention to a documentation source neglected by French historians of pharmacy: invention patents. He shows how to take advantage of these documents, provides an example of their interest and analyzes globally the corpus of legally-approved patents by pharmacists from 1836 to 1852.

France↗
PubMed1993

Balloon mitral valvotomy by using the Twin-AT catheter: immediate results and complications in 110 patients.

Balloon mitral valvotomy, using a new Twin AT catheter (two balloons attached side by side over one shaft), was performed in 110 consecutive cases. The age of the patients ranged from 19-78 yr (mean 46 +/- 15). From a total of 94 females and 16 males, 23 of the patients (22%) had mitral valve calcification, 47 patients (46%) had atrial fibrillation, and 39 patients (37%) had mitral regurgitation (< +2). Twenty patients (18%) presented with restenosis following surgical commissurotomy. Total catheterization time was 101 +/- 26 min and the duration of the valvotomy procedure was 37 +/- 21 min in these cases. For the entire population, there was a significant reduction in mitral valve gradient (15 +/- 6 to 4.8 +/- 2.6 mmHg, p < .001), an increase in mitral valve area (MVA) (1.1 +/- 0.3 to 2.35 +/- 0.7 cm2, p < .001), and a decrease in mean pulmonary arterial pressure (31 +/- 12 to 26 +/- 11, p < .002) after the balloon mitral valvotomy. Sixteen patients (14%) developed significant left to right shunt, and in 22 patients (20%) mitral regurgitation increased moderately but without resulting in emergency valve replacement. There was one incidence of embolic episode and one pericardial tamponade. Adequate hemodynamic results (MVA > 1.5 cm2 and % increase in MVA > or = 50%) without major complications were obtained in 99 cases. In 9 patients with severely diseased valve (2 previous commissurotomy, one restenosis after balloon valvotomy), or small left ventricular cavity, insufficient results were obtained by the Twin-AT catheter.(ABSTRACT TRUNCATED AT 250 WORDS)

Balloon Occlusion↗