References of "Fillet, Marianne"
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See detailFully automated method for the liquid chromatographic-tandem mass spectrometric determination of cyproterone acetate in human plasma using restricted access material for on-line sample clean-up.
Christians, Benoit; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal of Chromatography. A (2004), 1056(1-2), 105-10

A new automated method for the quantitative analysis of cyproterone acetate (CPA) in human plasma has been developed using on-line solid phase extraction (SPE) prior to the LC-MS/MS determination. The ... [more ▼]

A new automated method for the quantitative analysis of cyproterone acetate (CPA) in human plasma has been developed using on-line solid phase extraction (SPE) prior to the LC-MS/MS determination. The method was based on the use of a pre-column packed with internal-surface reversed-phase material (LiChrospher RP-4 ADS, 25 mm x 2 mm) for sample clean-up coupled to LC separation on an octadecyl silica stationary phase by means of a column switching system. A 30 microl plasma sample volume was injected directly onto the pre-column using a mixture of water, acetonitrile and formic acid (90:10:0.1 (v/v/v)) adjusted to pH 4.0 with diluted ammonia as washing liquid. The analyte was then eluted in the back-flush mode with the LC mobile phase consisting of water, methanol and formic acid (10:90:0.1 (v/v/v)). The dispensing flow rates of the washing liquid and the LC mobile phase were 300 microl min(-1). Medroxyprogesterone acetate (MPA) was used as internal standard. The MS ionization of the analytes was achieved using electrospray (ESI) in the positive ion mode. The pseudomolecular ionic species of CPA and MPA (417.4 and 387.5) were selected to generate daughter ions at 357.4 and 327.5, respectively. Finally, the developed method was validated according to a new approach using accuracy profiles as a decision tool. Very good results with respect to accuracy, detectability, repeatability, intermediate precision and selectivity were obtained. The LOQ of cyproterone acetate was 300 pg ml(-1). [less ▲]

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See detailRaloxifene protects Osteoblasts from apoptosis induced by sodium nitroprusside: Potential involvement of ceramide
Olivier, Sabine ULg; Fillet, Marianne ULg; Malaise, Michel ULg et al

in Journal of Bone and Mineral Research (2003, September), 18(Suppl. 2), 136

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See detailEffects of background electrolyte composition and addition of selectors on separation selectivity in nonaqueous capillary electrophoresis
Fillet, Marianne ULg; Servais, Anne-Catherine ULg; Crommen, Jacques ULg

in Electrophoresis (2003), 24(10), 1499-1507

This review gives a survey of the approaches employed to obtain, enhance and tune selectivity in nonaqueous capillary electrophoresis (NACE). Recent developments in NACE are described and the effects of ... [more ▼]

This review gives a survey of the approaches employed to obtain, enhance and tune selectivity in nonaqueous capillary electrophoresis (NACE). Recent developments in NACE are described and the effects of background electrolyte composition and addition of selectors on separation selectivity are discussed. The use of one organic solvent, a mixture of several organic solvents or the use of additives to tune separation selectivity in NACE is presented and a list of relevant applications is included. [less ▲]

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See detailMechanisms involved in exogenous C2- and C6-ceramide-induced cancer cell toxicity.
Fillet, Marianne ULg; Bentires-Alj, Mohamed; Deregowski, Valérie et al

in Biochemical Pharmacology (2003), 65(10), 1633-42

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation, and programmed cell death. To determine whether ceramides can mediate the ... [more ▼]

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation, and programmed cell death. To determine whether ceramides can mediate the apoptosis of HCT116 and OVCAR-3 cancer cells, exogenous C2-, C6-, and C16-ceramides were used to mimic the endogenous lipid increase that follows a large variety of stresses. C2- and C6-ceramides (cell-permeable ceramide analogs), but not C16-ceramide, induced nuclear factor-kappaB (NF-kappaB) DNA-binding, caspase-3 activation, poly(ADP-ribose) polymerase degradation, and mitochondrial cytochrome c release, indicating that apoptosis occurs through the caspase cascade and the mitochondrial pathway. No difference in survival was observed between control cells and cells expressing mutated IkappaBalpha and treated with the permeable ceramides. This suggests that, at least in these cell lines, stable NF-kappaB inhibition did not modify the ceramide-induced cytotoxicity pathway. C6-ceramide also induced a double block in G1 and G2, thus emptying the S phase. [less ▲]

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See detailCeramides play a critical role in spontaneous neutrophil apoptosis
Seumois, G.; Fillet, Marianne ULg; Gillet, Laurent ULg et al

Poster (2003)

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See detailNF-κB transcription factor induces drug resistance through MDR1 expression in cancer cells
Bentires-Alj, Mohamed; Barbu, Véronique; Fillet, Marianne ULg et al

in Oncogene (2003), 22

The ubiquitous NF-kappaB transcription factor has been reported to inhibit apoptosis and to induce drug resistance in cancer cells. Drug resistance is the major reason for cancer therapy failure and ... [more ▼]

The ubiquitous NF-kappaB transcription factor has been reported to inhibit apoptosis and to induce drug resistance in cancer cells. Drug resistance is the major reason for cancer therapy failure and neoplastic cells often develop multiple mechanisms of drug resistance during tumor progression. We observed that NF-kappaB or P-glycoprotein inhibition in the HCT15 colon cancer cells led to increased apoptotic cell death in response to daunomycin treatment. Interestingly, NF-kappaB inhibition through transfection of a plasmid coding for a mutated IkappaB-alpha inhibitor increased daunomycin cell uptake. Indeed, the inhibition of NF-kappaB reduced mdr1 mRNA and P-glycoprotein expression in HCT15 cells. We identified a consensus NF-kappaB binding site in the first intron of the human mdr1 gene and demonstrated that NF-kappaB complexes could bind with this intronic site. Moreover, NF-kappaB transactivates an mdr1 promoter luciferase construct. Our data thus demonstrate a role for NF-kappaB in the regulation of the mdr1 gene expression in cancer cells and in drug resistance. [less ▲]

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See detailSynergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis
Servais, Anne-Catherine ULg; Fillet, Marianne ULg; Abushoffa, Adel M. et al

in Electrophoresis (2003), 24(3), 363-369

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with ... [more ▼]

The enantiomeric separation of various kinds of basic pharmaceuticals has been investigated in nonaqueous capillary electrophoresis (NACE) systems using an ion-pairing reagent in combination with cyclodextrins (CDs). The simultaneous addition to the methanolic background electrolyte (BGE) of (+)-S-camphorsulfonate or alkanesulfonates and an anionic beta-cyclodextrin derivative, heptakis(2,3-dimethyl-6-sulfato)-beta-cyclodextrin (HDMS-beta-CD), led to partial or complete enantioresolution in most cases. In the absence of ion-pairing reagent, the enantiomeric resolution obtained with this CD derivative was most often completely lost or strongly reduced, indicating the important role of ion-pairing in the chiral recognition mechanism in these NACE systems. The influence of the nature and concentration of the counterion and the anionic CD derivative on the enantioseparation of basic compounds was studied. Synergistic effects between these two kinds of charged additives were clearly observed. [less ▲]

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See detailEnantiomeric separation of aminoglutethimide by capillary electrophoresis using native cyclodextrins in single and dual systems
Abushoffa, A. M.; Fillet, Marianne ULg; Marini Djang'Eing'A, Roland ULg et al

in Journal of Separation Science (2003), 26(6-7), 536-542

Aminoglutethimide (AGT) is one of the few examples of chiral drugs that can be enantioseparated by capillary electrophoresis using any of the three native cyclodextrins: alpha-, beta-, or gamma-CD. A ... [more ▼]

Aminoglutethimide (AGT) is one of the few examples of chiral drugs that can be enantioseparated by capillary electrophoresis using any of the three native cyclodextrins: alpha-, beta-, or gamma-CD. A complete resolution of the enantiomers of this compound in cationic form could be achieved with each of the three CDs, using a pH 3 phosphoric acid-triethanolamine buffer. Affinity constants for AGT enantiomers with the three native CDs were determined, confirming that the highest selectivity was given by gamma-CD while the strongest complexation was obtained with beta-CD. However, an opposite affinity pattern was observed with the latter. Selectivity was lower for AGT enantiomers in dual CD systems, compared to that obtained with a single selector at its optimal concentration, which confirms that dual systems are of more limited interest when the two selectors have a similar effect on the analyte mobility. These results are in good agreement with those predicted using recently developed mathematical models. [less ▲]

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See detailEnhancement of selectivity and resolution in the enantioseparation of uncharged compounds using mixtures of oppositely charged cyclodextrins in capillary electrophoresis.
Abushoffa, Adel M; Fillet, Marianne ULg; Servais, Anne-Catherine ULg et al

in Electrophoresis (2003), 24(3), 343-50

The enantiomeric separation of some nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated in capillary electrophoresis (CE) using dual systems with mixtures of charged cyclodextrin (CD ... [more ▼]

The enantiomeric separation of some nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated in capillary electrophoresis (CE) using dual systems with mixtures of charged cyclodextrin (CD) derivatives. A significant enhancement of selectivity and resolution could be achieved in the enantioseparation of these analytes in their uncharged form by the simultaneous addition of two oppositely charged CD derivatives to the background electrolyte. The combination of the single-isomer cationic CD, permethyl-6-monoamino-6-monodeoxy-beta-CD (PMMAbetaCD) and the single-isomer polyanionic CD, heptakis-6-sulfato-beta-cyclodextrin (HSbetaCD) in a pH 2.5 phosphoric acid-triethanolamine buffer, was designed and employed for the enantioseparation of profens. The improvement in selectivity and resolution can be attributed to the fact that the two CDs, which lead to independent and enantioselective complexation with the analyte enantiomers, have not only opposite effects on the electrophoretic mobility of these compounds but also opposite affinity patterns towards the enantiomers of these compounds. Binding constants for these enantiomers with each CD were determined using linear regression approach, in order to be able to predict the effect of the concentrations of the two CDs on enantiomeric selectivity and resolution in such dual systems. [less ▲]

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