Biomedical subjects

S Diabaté

Publications and source records attributed to S Diabaté.

5 recordsLinked to original sources

PubMed2003

Formation of reactive oxygen species in rat epithelial cells upon stimulation with fly ash.

Fly ash was used as a model for ambient particulate matter which is under suspicion to cause adverse pulmonary health effects. The fly ash was pre-sized and contained only particles < 20 microm including an ultrafine fraction (< 100 nm) that contributed 31% to the particle number. In our study, we investigated the influence of fly ash on the promotion of early inflammatory reactions like the formation of reactive oxygen species (ROS) in rat lung epithelial cells (RLE-6TN). Furthermore, we determined the formation of nitric oxide (NO). The cells show a clear dose-response relationship concerning the formation of ROS with regard to the mass of particles applied. Lipopolysaccharide (LPS) added as a co-stimulus did not increase the formation of ROS induced by fly ash. Furthermore, in LPS (0.1 microg/ml) and tumour necrosis factor-alpha (TNF-alpha; 1 ng/ml) pre-treated cells no increase in reactive oxygen species comparable to fly ash alone is observable. In presence of the metal chelator, desferrioxamine (DFO), ROS formation can be significantly reduced. Neither fly ash nor LPS induced a significant NO release in RLE-6TN cells.

Air Pollutants↗

PubMed2002

Tissue free water tritium and organically bound tritium in the rice plant acutely exposed to atmospheric HTO vapor under semi-outdoor conditions.

Potted rice plants were exposed to atmospheric HTO in a box outdoors for 1 h at 9 different times from booting to yellow-ripe stages. It is indicated that the leaf TFWT concentration may reach equilibrium within 1 h in clear weather. The plant TFWT concentration decreased at a rapid rate for the first several hours and at a much slower rate thereafter. The decrease till harvest was by factors of 600-95,000 depending on the plant parts and exposure times. The time course of the ear OBT concentration was characterized by the exposure time. After exposure at the booting to heading stages, the leaf OBT concentration decreased rapidly for the first several hours and then very slowly. The plant OBT concentration was initially about 2 orders of magnitude lower, but at harvest an order of magnitude higher, than the TFWT concentration. The OBT concentration in hulled seeds at harvest varied with exposure times by a factor of 70, being highest in the exposure performed at the earlier stage of rapid grain growth. Also in this exposure, the plant total OBT was greatest due to the seed OBT.

Environmental Exposure↗

PubMed1993

Organically bound tritium.

Tritium released into the environment may be incorporated into organic matter. Organically bound tritium in that case will show retention times in organisms that are considerably longer than those of tritiated water which has significant consequences on dose estimates. This article reviews the most important processes of organically bound tritium production and transport through food networks. Metabolic reactions in plant and animal organisms with tritiated water as a reaction partner are of great importance in this respect. The most important production process, in quantitative terms, is photosynthesis in green plants. The translocation of organically bound tritium from the leaves to edible parts of crop plants should be considered in models of organically bound tritium behavior. Organically bound tritium enters the human body on several pathways, either from the primary producers (vegetable food) or at a higher tropic level (animal food). Animal experiments have shown that the dose due to ingestion of organically bound tritium can be up to twice as high as a comparable intake of tritiated water in gaseous or liquid form. In the environment, organically bound tritium in plants and animals is often found to have higher specific tritium concentrations than tissue water. This is not due to some tritium enrichment effects but to the fact that no equilibrium conditions are reached under natural conditions.

Animals↗

PubMed1984

Structure of the major oligosaccharides in the fusion glycoprotein of Newcastle disease virus.

The fusion glycoprotein (F0) was isolated from Newcastle disease virus (NDV) particles metabolically labelled with [2-3H]mannose; it was successively digested with protease and with endo-beta-N-acetylglucosaminidase from Streptomyces griseus. In this manner, the majority of the oligosaccharides in NDV F0 could be liberated. After reduction with NaBH4, they were separated by high-performance liquid chromatography, and were subjected to structural analysis. Using micromethylation/capillary gas chromatography/mass fragmentography, alpha-mannosidase digestion, and acetolysis, it was found that the enzymatically released NDV F0 oligosaccharides are common oligomannosidic glycoprotein glycans of size classes (Man)8GlcNAc, Man)7GlcNAc, (Man)6GlcNAc, (Man)9GlcNAc, and (Man)5GlcNAc (in order of prevalence). The major structural isomers present in the NDV F0 (Man)8GlcNAc to (Man)5GlcNAc fractions were shown to lack mannose residues D2, D1D2 or D2D3, D1D2D3, and CD1D2D3, respectively, of (Man)9GlcNAc.

Acetone↗

PubMed1983

Separation and sugar component analysis of the oligosaccharides in the surface glycoproteins of Newcastle disease virus.

The precursor glycoproteins HN0 and F0 in the surface spikes of Newcastle Disease Virus strain Ulster as produced by MDBK cells, were found to contain 10.4 and 11.9 weight per cent, respectively, of the sugars typical for N-glycosidically linked glycoprotein glycans. A molar ratio of D-mannose:D-galactose: L-fucose:N-acetyl-D-glucosamine approaching 1.0:1.1:0.5:1.0 was found for HN0, and of 1.0:0.7:0.3:0.6 for F0. By a sequence of degradation (with pronase, with endo-beta-N-acetylglucosaminidase H [endo H], and by hydrazinolysis) and separation procedures (Concanavalin A-affinity and Biogel P-4 chromatography), the radiolabelled carbohydrate moieties of NDV HN0 and F0 (as oligosaccharitols) were separated into (at least) ten and eight fractions, respectively. Separate in vivo labelling with tritiated derivatives of the four sugars showed that both glycoproteins contain oligosaccharides of the oligomannosidic ("high mannose"), of the N-acetyllactosaminic ("complex"), as well as of the "mixed" type. The majority of the oligosaccharides in F0, but not of those in HN0, was found to be endo H-sensitive.

Carbohydrates↗