References of "De Graeve, Jean"
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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
Christiaens, B.; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal of Chromatography. A (2004), 1056(1-2), 105-110

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 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 detailA structured strategy for assessing chemical risks, suitable for small and medium-sized enterprises
Balsat, Alain; De Graeve, Jean ULg; Mairiaux, Philippe ULg

in Annals of Occupational Hygiene (2003), 47(7), 549-556

BACKGROUND: A previous study carried out in 20 Belgian companies, especially small and medium-sized enterprises (SMEs), showed that prevention advisors did not use any structured approaches to assess ... [more ▼]

BACKGROUND: A previous study carried out in 20 Belgian companies, especially small and medium-sized enterprises (SMEs), showed that prevention advisors did not use any structured approaches to assess chemical risk. They used their personal judgement and the information contained in manufacturers' Safety Data Sheets to assess the risk. OBJECTIVE AND METHOD: The purpose of the Regetox network is to provide companies with a global approach for assessing chemical health risks. The structured approach proposed consists of two successive steps of increasing complexity. For the first step, we chose a method developed by the INRS (France), the 'ranking of potential risk', which allows the safety officer or staff member to identify hazards and to set priorities among all the supplied products used in the workplace. For the second step, we applied the COSHH method and EASE model established by the UK Health [less ▲]

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See detailA stepwise approach for chemical risks assessment at the workplace
Mairiaux, Philippe ULg; Balsat, Alain; Dujardin, Marco et al

Scientific journal (2003)

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See detailA stepwise approach for chemical risks assessment at the workplace
Mairiaux, Philippe ULg; Balsat, Alain; Dujardin, Marc ULg et al

in Strasser, H.; Kluth, K.; Rausch, H. (Eds.) et al Quality of work and products in enterprises of the future (2003)

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See detailSeparation, identification and quantitation of ceramides in human cancer cells by liquid chromatography–electrospray ionization tandem mass spectrometry
Fillet, Marianne ULg; Van Heugen, Jean-Claude ULg; Servais, Anne-Catherine ULg et al

in Journal of Chromatography. A (2002), 949

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation and programmed cell death. Qualitative and quantitative analysis of these second ... [more ▼]

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation and programmed cell death. Qualitative and quantitative analysis of these second messengers requires sensitive and specific analytical methods to detect endogenous levels of individual ceramide species and to differentiate between them. Nine synthetic ceramides were separated by liquid chromatography coupled to tandem mass spectrometry on a C bonded silica 18 column. The lipids were eluted in gradient elution mode using a mixture of water, acetonitrile and 2-propanol as mobile phase. They were detected by reaction monitoring performed on positive ion electrospray generated ions. Collision-induced fragmentations conducted on ceramides produced a well characteristic product ion at m/z 264, making multiple reaction monitoring (MRM) well suited for various ceramides quantitative measurements. After optimization of the extraction step, the proposed methodology was able to identify and quantify different ceramide species issued from human cancer cells. The method could be validated for C , C and C ceramides, quantified at the nanogram level. The validation exhibits good 16 18 20 results with respect to linearity, accuracy and precision. [less ▲]

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See detailComparison of monooxygenase activities and cytochrome P-450 isozyme concentrations in human liver microsomes.
Beaune, P H; Kremers, P G; Kaminsky, L S et al

in Drug Metabolism and Disposition : The Biological Fate of Chemicals (1986), 14(4), 437-42

Concentrations of three human liver microsomal cytochrome P-450 isozymes and 20 different monooxygenase activities were determined in human liver microsomal preparations. The results of correlation ... [more ▼]

Concentrations of three human liver microsomal cytochrome P-450 isozymes and 20 different monooxygenase activities were determined in human liver microsomal preparations. The results of correlation analysis suggest that: there are important variations in the amounts of the three cytochrome P-450 isozymes measured, particularly P-450(8) and P-450(9); aldrin epoxidase, d-benzphetamine N-demethylase, and S-warfarin 4-hydroxylase activities are linked to cytochrome P-450(5); aryl hydrocarbon (benzo(a)pyrene) hydroxylase and 4-nitroanisole-O-demethylase activities are linked to P-450(8); hydroxylations at the 4'-, 6-, 7-, and 8-positions of R-warfarin are closely linked to each other but are not correlated with other measured monooxygenase activities or P-450 isozyme levels; and P-450(9) is not related to any of the catalytic activities tested. Thus, certain monooxygenase activities can be attributed to specific cytochrome P-450 isozymes. This approach should be useful in suggesting the roles of different cytochromes P-450 in drug metabolism in man which can be further examined using in vitro and in vivo methods. [less ▲]

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See detailCardiovascular effects of intravenous tolmesoxide in hypertensive patients.
Scheen, André ULg; Luyckx, A. S.; De Graeve, Jean ULg

in Archives Internationales de Pharmacodynamie et de Thérapie (1981), 251(2), 322-34

Tolmesoxide, a potent vasodilating compound, was infused intravenously (0.5 to 3.5 mg/kg b.w., rate of infusion: 2.5 to 10.0 mg/min during 7--25 min, 2 or 3 successive infusions separated by a 30 min rest ... [more ▼]

Tolmesoxide, a potent vasodilating compound, was infused intravenously (0.5 to 3.5 mg/kg b.w., rate of infusion: 2.5 to 10.0 mg/min during 7--25 min, 2 or 3 successive infusions separated by a 30 min rest period) in 7 hypertensive patients. An abrupt fall in blood pressure and heart rate occurred in 4 patients whereas 2 patients exhibited almost no hemodynamic response. The remaining case suffering from renovascular hypertension responded with a progressive dose-dependent decrease in blood pressure. No obvious correlation could be demonstrated between the drug plasma levels (ranging between 1.0 and 11.1 microgram/ml) and the hemodynamic effects among the 7 patients studied. [less ▲]

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