PubMed Health⌕ Search

Biomedical subjects

J Guillot

Publications and source records attributed to J Guillot.

At least 55 records · Page 3Linked to original sources
PubMed1998

Expression of Tn antigen and N-acetyllactosamine residues in malignant and benign human breast tumors detected by lectins and monoclonal antibody 83D4.

Expressions of the carcinoembryonic Tn antigen studied with VVA-B4 and GSI-A4 lectins with the monoclonal antibody 83D4 and of N-acetyllactosamine residues with ECA and LSL lectins, were examined in 54 malignant or benign human breast tumors. Positive membrane labelling with lectins and 83D4 MAb occured in benign cases indicating that modification of glycoconjugates may precede the cytologic anomalies. In fibroadenoma, fibrocystic dystrophy, ductal hyperplasia and grade I invasive ductal carcinomas, the binding sites for all lectins and 83D4 MAb were essentially on the cell membrane with labelling of both apical and basolateral compartments. In grade II and III, the labelling involved the cytoplasm, and cell heterogeneity appeared. The disappearance of reactivity observed for a large proportion of cells at grade III may be due either to the loss of glycosyl-transferase, or to the lack of synthesis of the protein back-bone. Invasive lobular carcinomas showed labelling both on apical membrane and the outermost part of the cytoplasm with a distinct cell polarity. Lectin receptors are present at the surface of metastatic cells, possibly related to their involvement in adhesion.

Amino Sugars↗
PubMed1998

[Expression of T and Tn antigens in breast cancers].

Expression of carcinoembryonic Tn antigen studied with VVA-B4 and GSI-A4 lectins with the monoclonal antibody 83D4 and of T antigen with LDL and PNA lectins with the monoclonal antibody ZCMO4, were examined in 54 malignant or benign human breast tumors and for MCF-7, T47D and MCF-10A cell lines of human breast tumors origin. For breast tissues, positive membrane labelling with D-GalNAc alpha-O-ser/thr (Tn-antigen) specific lectins and 83D4 MAb occurred in benign cases indicating that modification of glycoconjugates may precede the cytologic anomalies. In fibroadenoma, fibrocystic dystrophy, ductal hyperplasia and grade I invasive ductal carcinomas, the binding sites for lectins and 83D4 MAb were essentially on the cell membrane with labelling of both apical and basolateral compartments. In grade II and III, the labelling involved the cytoplasma, and cell heterogeneity appeared. The disappearance of reactivity observed for a large proportion of cells at grade III may be due either to the loss of glycosyltransferase, or to the lack of synthesis of the protein back-bone. Invasive lobular carcinomas showed labelling both on apical membrane and the outermost part of the cytoplasm with a distinct cell polarity. Lectin receptors are present at the surface of metastatic cells, possibly related to their involvement in adhesion. In all cases, T or sialosyl-T antigens are present at the surface of tumors cells. All cell lines from breast tumors cultured in vitro were labelled with lectins and monoclonal antibodies. The simultaneous presence of Tn and T antigens on the cells, indicates that the expression of Tn antigen is due to a partial but non total deficiency in the beta-1- > 3 galactosyltransferase involved in T-antigen synthesis.

Adult↗
PubMed1998

The role of Malassezia species in the ecology of human skin and as pathogens.

The new taxonomic structure of the lipophilic genus Malassezia was presented with key characteristics for the seven described species. Among techniques used for epidemiological surveys, the pulsed field gel electrophoresis (PFGE) was found to be of little value in contrast to randomly amplified polymorphic DNA (RAPD). Immunological studies still yielded conflicting results but at least the immunomodulatory capacity of Malassezia yeasts appeared to be related to the cell wall lipids. A review of Malassezia infections together with the present consensus for their prevention and treatment was also made.

Antibodies, Fungal↗
PubMed1997

Toxicity assessment of 16 inorganic environmental pollutants by six bioassays.

The relative toxicity of 16 environmental pollutants, such as inorganic elements (Ba, Cd, Co, Cr, Cu, Fe, Ge, Hg, Mn, Nb, Pb, Sb, Sn, Ti, V, and Zn), is evaluated on the L-929 established cell line of murine fibroblasts, with five bioassays [RNA synthesis rate assay (RNA), MTT reduction assay (MTT), neutral red incorporation assay (NRI), Coomassie blue assay, and cellular growth rate assay], and on the ciliated protozoa Tetrahymena pyriformis GL [doubling time of T. pyriformis GL population assay (DTP)]. For each inorganic substance, the six bioassays allowed the toxicological index IC50 ("inhibitory concentration 50%") to be calculated. The IC50 values are useful to rank the tested elements and to compare the features of the six bioassays. The most sensitive assays were the RNA, MTT, NRI, and DTP assays. Moreover, the in vitro IC50 values correlated with the in vivo LD50 values; these results were close to those obtained with established lines of human, murine, or fish cells. The sensitivity and the complementarity of these bioassays would be in favor of their incorporation in a "battery" of tests used for toxicological screening studies of xenobiotics.

Animals↗
PubMed1997

Detection of antibodies to Aspergillus fumigatus in serum of horses with mycosis of the auditory tube diverticulum (guttural pouch).

OBJECTIVE: To detect antibodies against Aspergillus fumigatus antigens in serum samples from horses and to evaluate the relevance of this method as an alternative approach to the diagnosis of mycosis of the auditory tube diverticulum (guttural pouch mycosis [GPM]). ANIMALS: Twelve clinically normal horses (controls) and 12 horses with GPM diagnosed by endoscopic observation of characteristic mycotic plaques. PROCEDURE: Antibodies to A fumigatus antigens were detected in serum by use of an ELISA and immunoblot analysis with extracellular antigens. RESULTS: Antibodies against A fumigatus antigens were found in healthy and diseased horses. Titer of total Aspergillus antibodies was not diagnostic for GPM. In contrast, immunoblot analysis results indicated that 2 antigens of 22 and 26 kd were constantly recognized by sera from diseased horses. CONCLUSIONS: Reactivity to 22- and 26-kd A fumigatus antigens, as measured by immunoblot analysis, seemed to be diagnostic for GPM in horses.

Animals↗
PubMed1996

The genus Malassezia with description of four new species.

The genus Malassezia has been revised using morphology, ultrastructure, physiology and molecular biology. As a result the genus has been enlarged to include seven species comprising the three former taxa M. furfur, M. pachydermatis and M. sympodialis, and four new taxa M. globosa, M. obtusa, M. restricta and M. slooffiae. The descriptions of all the species include morphology of the colonies and of the cells, together with ultrastructural details. The physiological properties studied were the presence of catalase, the tolerance of 37 degrees C and the ability to utilize certain concentrations of Tween 20, 40, 60 and 80 as a source of lipid in a simple medium. Information is given for each of the taxa on mole% GC and also the rRNA sequence from the comparison previously described for the genus.

Catalase↗
PubMed1995

Confirmation of the nomenclatural status of Malassezia pachydermatis.

Malassezia strains from dogs and rhinoceros all proved identical using mole% G+C and nDNA/DNA reassociation experiments. The use of the name Malassezia pachydermatis, originally described for a strain isolated from a rhinoceros, is thus justified for non lipid-dependent strains of other sources.

Animals↗
PubMed1995

The diversity of Malassezia yeasts confirmed by rRNA sequence and nuclear DNA comparisons.

One hundred and four Malassezia strains (52 isolated from humans and 52 from animals) were compared using large subunit (LSU) ribosomal RNA sequence similarity and nuclear DNA complementarity. Eight groups of strains were recognized as genetically distinct species. Each taxon was confirmed by a homogeneous mole % GC and percentages of DNA/DNA reassociations higher than 85%. The non-lipid-dependent Malassezia yeasts were maintained as the unique taxon M. pachydermatis. In contrast, lipid-dependent strains were shown to be distributed among seven species: M. furfur, M. sympodialis and M. species 1-5. These taxa matched remarkably well with morphological and serological differences documented by previous investigators. The LSU rRNA sequences allowed a further intraspecific resolution with most of genomic taxa represented by several closely related sequences: M. pachydermatis counted up to seven sequences, M. furfur four sequences, M. species 1 comprised three sequences and M. species 2 and M. species 5 two sequences. Three species, M. sympodialis, M. species 3 and M. species 4, displayed a unique type of sequence. Thus, the present report demonstrates the usefulness of sequencing for both taxonomic and epidemiological purposes.

Animals↗
PubMed1994

Isolation and characterization of an N-acetyllactosamine-binding lectin from the mushroom Laetiporus sulfureus.

A hemagglutinating and hemolytic lectin (PSL) has been isolated from carpophores of the parasitic mushroom Laetiporus sulfureus by affinity chromatography on Sepharose. Its molecular weight, as determined both by gel filtration and by electrophoresis in non-denaturing conditions, is about 190,000 and its structure is tetrameric, with two distinct types of subunits (about 60,000 and 36,000). It appeared homogeneous on HPLC gel filtration but exhibited microheterogeneity on isoelectric focusing. Hapten inhibition assay indicated that the Laetiporus lectin is specific for N-acetyllactosamine residues and that hemagglutinating and hemolysis activities are supported by the same site.

Amino Sugars↗