Anne Nicolas

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We report an HPLC method for measuring the concentrations of reduced (GSH) and total (GSHt) free glutathione in human plasma and whole blood. The chromatographic step was coupled with a postcolumn derivatization reaction and fluorometric detection. The linear range was 0.81-13.02 mumol/L, and the detection limit was 0.13 mumol/L. In healthy adults (ages(More)
We have determined the crystal structure at 1.8 A resolution of a complex of alpha-bungarotoxin with a high affinity 13-residue peptide that is homologous to the binding region of the alpha subunit of acetylcholine receptor. The peptide fits snugly to the toxin and adopts a beta hairpin conformation. The structures of the bound peptide and the homologous(More)
A simple and fast high-performance liquid chromatographic method was developed for the simultaneous measurement of 2-mercaptopropionylglycine (Tiopronine) and its metabolite (2-mercaptopropionic acid) in human plasma after the administration of a pharmaceutical dosage form (Acadione). The sample treatment before high-performance liquid chromatographic(More)
A high-performance liquid chromatography (HPLC) method to determine the most important cellular thiols [reduced glutathione (GSH), cysteine, gamma-glutamylcysteine and cysteinylglycine] is described. Separation relies upon isocratic ion-pairing reversed-phase chromatography and detection is operated by spectrofluorimetry coupled with post-column(More)
Residues of two antibacterial agents, cephalexin and colistin, co-administered by intramuscular injection to calves, were quantified in four different tissues (muscle, fat, liver and kidney) by column switching HPLC and by a microbiological method. For cephalexin assay, tissue samples with cephradin as internal standard were homogenized in a 5%(More)
A rapid and simple method for the separation and quantitation of gentamicin sulfate by HPLC coupled with evaporative light scattering detection (ELSD) has been developed. Detection of the different components of gentamicin is problematic because of the lack of UV absorbing chromophore. The use of the universal ELSD avoids the need for sample derivatization(More)
Penicillamine exists as 2 stereoisomers, but only the D-isomer is used therapeutically. Its chemical reactivity derives from its functional groups, of which the thiol group seems the most important. It is difficult to determine penicillamine in biological fluids because of its instability, the presence of endogenous compounds with a thiol function, and the(More)
A rapid, sensitive and selective method for the assay of glutathione in cultured cells has been developed using ion-pair reversed phase rapid high performance liquid chromatography. The use of a 4 micron particle, 5 cm long column (Superspher 100 RP 18 end-capped) allowed complete analysis of glutathione within 3 min. A postcolumn derivatization reaction(More)