References of "De Pauw, Edwin"
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See detailAssessment of the impact of an old MSWI. Part1 : Level of PCDD/Fs and PCBs in surrounding soils and eggs
Pirard, Catherine; Focant, Jean-François ULg; Massart, Anne-Cécile ULg et al

in Organohalogen Compounds (2004), 66

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See detailDR-CALUX((R)) screening of food samples: evaluation of the quantitative approach to measure dioxin, furans and dioxin-like PCBs
Scippo, Marie-Louise ULg; Eppe, Gauthier ULg; De Pauw, Edwin ULg et al

in Talanta (2004), 63(5), 1193-1202

European legislation laid down maximum tolerable levels of dioxin in feed and food as well as analytical method requirements. In order to face with large monitoring programs, it was foreseen in the EU ... [more ▼]

European legislation laid down maximum tolerable levels of dioxin in feed and food as well as analytical method requirements. In order to face with large monitoring programs, it was foreseen in the EU strategy to integrate screening methods, using either a qualitative (screening) approach, or a quantitative approach. In this study, dioxin results obtained using the Dioxin Responsive Chemical-Activated LUciferase gene eXpression (DR-CALUX(R)) cell-based assay (quantitative approach), were compared with gas chromatography-high resolution mass spectrometry (GC-HRMS) analyses data. Instead of using World Health Organization-toxic equivalent factor (WHO-TEF), the comparison was based on the assessment of relative effective potencies (REPs) for each congener of the 17 toxic 2,3,7,8-polychlorodibenzo-p-dioxins/furans (PCDD/Fs) and 12 dioxin-like polychlorobiphenyls (DL-PCBs). According to published data, DR-CALUX(R)-REP evaluated here appear similar to WHO-TEF for PCDD/Fs while lower values were observed for DL-PCBs. We analyzed two "home made" contaminated fat samples, displaying both the same WHO-toxic equivalent quantities (WHO-TEQ) concentration (12 pg WHO-TEQ g(-1)). They were spiked with either a low or a high amount of DL-PCBs. In both cases, the DR-CALUX(R) measured concentration (picogram 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) eq. g(-1)) corresponded to the PCDD/Fs WHO-TEQ concentration only. A good agreement was nevertheless found between the DR-CALUX(R) measurements and the recalculated DR-CALUX(R)-TEQ contents (using DR-CALUX(R)-REP instead of WHO-TEF), demonstrating that the observed response was due, in both cases, to the addition of the responses of the standards added to the fat. By contrast, in real contaminated samples (feed or cod liver samples), DR-CALUX(R) measured concentrations were similar to WHO-TEQ GC-HRMS measured concentrations. But, depending on the PCDD/Fs and DL-PCBs congener content, the DR-CALUX(R) measured concentrations were either lower or higher than calculated DR-CALUX(R)-TEQ contents, demonstrating that possible co-extracted contaminants contributed to the CALUX response. Owing to these divergences, the quantitative determination of dioxin-like content in food and feed using CALUX as screening method is questionable, except for samples displaying constant congener patterns, in which cases, correction factors could be applied. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailInvestigation of non-covalent interactions between paramagnetic complexes and human serum albumin by electrospray mass spectrometry
Henrotte, Virginie; Laurent, Sophie ULg; Gabelica, Valérie ULg et al

in Rapid Communications in Mass Spectrometry : RCM (2004), 18(17), 1919-1924

Stable gadolinium(III) chelates are nowadays routinely used as contrast agents for magnetic resonance imaging (MRI). Their non-covalent binding to human serum albumin (HSA) has shown to improve their ... [more ▼]

Stable gadolinium(III) chelates are nowadays routinely used as contrast agents for magnetic resonance imaging (MRI). Their non-covalent binding to human serum albumin (HSA) has shown to improve their efficacy. Non-covalent interactions lead to complex formation that can be quantified by several techniques that are mostly tedious and time-consuming. In this study, electrospray ionization mass spectrometry (ESI-MS) was used to investigate the interaction between HSA and several gadolinium(III) complexes. The results were compared with those obtained in the liquid phase. Four gadolinium complexes were investigated: Gd-DTPA 1, Gd-C4Me-DTPA 2, Gd-EOB-DTPA 3, and MP-2269 4. Relaxometry studies show that complexes 1 and 2 have no significant affinity for HSA, while complexes 3 and 4 have increasing affinities for the protein. 1:1 and 1:2 complexes between HSA and MP-2269 were detected by ESI-MS for a twofold excess of the contrast agent, whereas a ligand/protein molar ratio of 4:1 was necessary to observe a 1:1 stoichiometry for Gd-EOB-DTPA, an observation that is in good agreement with the known weaker affinity of the contrast agent for the protein. At a fourfold molar excess, no supramolecular complex was observed for Gd-DTPA I and Gd-C4Me-DTPA 2; a tenfold molar excess was necessary to detect a 1:1 complex, confirming the very weak affinity of these contrast agents for HSA. [less ▲]

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See detailInfluence of the capillary temperature and the source pressure on the internal energy distribution of electrosprayed ions
Gabelica, Valérie ULg; De Pauw, Edwin ULg; Karas, Michael

in International Journal of Mass Spectrometry (2004), 231(2-3), 189-195

The internal energy distributions in a heated capillary nano-electrospray source have been determined using the "survival yield" method. At low capillary temperatures, the internal energy distribution is ... [more ▼]

The internal energy distributions in a heated capillary nano-electrospray source have been determined using the "survival yield" method. At low capillary temperatures, the internal energy distribution is characterized by a low-energy tail, which can be attributed to a fraction of ions not fully desolvated in the heated capillary. This low-energy tais is shown to disappear when the source pressure is increased. This explains why increased source pressure is favorable in the case of highly hydrophilic compounds or non-covalent complexes in order to achieve sufficient desolvation without fragmentation. It is also shown that "high temperature-low voltage" are not equivalent to "low temperature-high voltage" source conditions. These observations are important for fundamental issues as well as for source-CID mass spectral library searching applications. [less ▲]

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See detailComparison of the rat and mouse cell lines commercially available for CALUX bioassays
Goeyens, Leo; Windal, Isabelle; Scippo, Marie-Louise ULg et al

in Organohalogen compounds (2004), 66

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See detailLevels of contamination for various pollutants present in Belgian human plasma
Van Wouwe, Nathalie; Covaci, Adrian; Kannan, Kurunthachalam et al

in Organohalogen Compounds (2004)

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See detailDIOXIN BODY BURDEN AMONG BLOOD DONORS BEFORE AND AFTER THE BELGIAN DIOXIN/PCB INCIDENT
Debacker, Noemi; Sasse, André; Van Wouwe, Nathalie et al

in Organohalogen Compounds (2004)

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See detailApplication of the CALUX bioassay for epidemiological study: analyses of Belgian human plasma
Van Wouwe, Nathalie; Debacker, Noemi; Sasse, André et al

in Organohalogen Compounds (2004)

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See detailIdentification of specific biomarkers related to the effects of pollutants on the immune system of marine mammals
Brenez, Cécile; Gerkens, Pascal; Jauniaux, Thierry ULg et al

Poster (2003, December)

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See detailDioxin/polychlorinated biphenyl body burden, diabetes and endometriosis: findings in a population-based study in Belgium
Fierens, S.; Mairesse, H.; Heilier, J. F. et al

in Biomarkers : Biochemical Indicators of Exposure, Response, & Susceptibility to Chemicals (2003), 8(6), 529-534

Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants widely distributed in the food chain, which is the main source of human exposure. Their effects on human health at background ... [more ▼]

Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants widely distributed in the food chain, which is the main source of human exposure. Their effects on human health at background exposure levels are still poorly understood. Recent epidemiological evidence suggests a possible association between these pollutants and diabetes. We report here the results of a population-based study in Belgium on 257 (142 women and 115 men) environmentally exposed subjects, including 10 cases of endometriosis and nine cases of diabetes. Seventeen 2,3,7,8-polychlorinated dibenzodioxins/dibenzofurans (PCDD/Fs or dioxins), four coplanar PCBs (International Union of Pure and Applied Chemistry [IUPAC] nos 77, 81, 126 and 169) and 12 PCB markers ( IUPAC nos 3, 8, 28, 52, 101, 118, 138, 153, 180, 194, 206 and 209) were quantified in serum fat from fasting blood samples in order to estimate the body burden of these pollutants. Whilst no difference was found between women with endometriosis and their controls, diabetic patients had significantly increased serum levels of dioxins, coplanar PCBs and the 12 PCB markers. After adjustment for age and other covariates, serum total toxic equivalent activity (sum of PCDD/Fs and coplanar PCBs) and 12 PCB marker concentrations in diabetics were 62% (p=0.0005) and 39% (p=0.0067) higher, respectively, than in controls. The risk of diabetes was significantly increased in subjects in the top decile for adjusted concentrations of dioxins (odds ratio 5.1, 95% confidence interval [CI] 1.18-21.7), coplanar PCBs (odds ratio 13.3, 95% CI 3.31-53.2) or 12 PCB markers (odds ratio 7.6, 95% CI 1.58-36.3). These findings warrant further studies to assess the significance of the associations between diabetes and environmental exposure to polychlorinated pollutants. [less ▲]

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See detailSelective interaction of ethidium derivatives with quadruplexes: An equilibrium dialysis and electrospray ionization mass spectrometry analysis
Rosu, Frédéric ULg; De Pauw, Edwin ULg; Guittat, Lionel et al

in Biochemistry (2003), 42(35), 10361-10371

The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to directly inhibit telomerase activity. The reactivation of this enzyme in ... [more ▼]

The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to directly inhibit telomerase activity. The reactivation of this enzyme in immortalized and most cancer cells suggests that telomerase is a relevant target in oncology, and telomerase inhibitors have been proposed as new potential anticancer agents. In this paper, we have analyzed the selectivity of four ethidium derivatives and ethidium itself toward different G-quadruplex species, with electrospray mass spectrometry and competitive equilibrium dialysis and evaluated their inhibitory properties against telomerase. A selectivity profile may be obtained through electrospray ionization mass spectrometry (ESI-MS), which is in fair agreement with competitive equilibrium dialysis data. It also provides unambiguous data on the number of binding sites per nucleic acid (maximal number of two ethidium derivatives per quadruplex, in agreement with external stacking). Our experiments also demonstrate that one compound (4) is the most active and selective G-quadruplex ligand within this series and the most selective telomerase inhibitor in a modified TRAP-G4 assay. [less ▲]

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See detailComprehensive Analysis of PBDEs, PCDD/Fs and PCBs
PIRARD, Catherine ULg; De Pauw, Edwin ULg; Focant, Jean-François ULg

Conference (2003, August)

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See detailDioxin accumulation in residents around incinerators
Fierens, S.; Mairesse, H.; Hermans, C. et al

in Journal of Toxicology and Environmental Health. Part A (2003), 66(14), 1287-1293

To evaluate the human exposure impact of municipal waste incinerators, dioxin and coplanar polychlorinated biphenyl (PCB) concentrations were determined in blood of 84 subjects who resided approximately ... [more ▼]

To evaluate the human exposure impact of municipal waste incinerators, dioxin and coplanar polychlorinated biphenyl (PCB) concentrations were determined in blood of 84 subjects who resided approximately 18 yr in the vicinity of two old incinerators, one located in a rural area (n = 51) and the other in an industrial area (n = 33). These subjects were compared with 63 controls from an unpolluted area. While no change was found in contaminant levels in residents living around the incinerator in the industrial area, subjects residing around the incinerator in the rural area possessed significantly higher serum levels of dioxins (38 vs. 24 pg TEQ/g fat) and coplanar PCBs (10 vs. 7 pg TEQ/g fat) than controls. These results were confirmed by multiple-regression analysis, showing that residence around the incinerator in the rural area (partial r(2) = .18) was the major contributor to dioxin accumulation followed by age (partial r(2) = .07). A two-way analysis of variance (ANOVA) on age-adjusted dioxin levels revealed a significant interaction between residence around incinerators and the consumption of fat from local origin, especially bovine and poultry products. Although age-adjusted dioxin levels in controls did not vary with local animal fat consumption, concentrations of dioxins in subjects living around the incinerators increased proportionally to their intake of local animal fat, with almost a doubling in subjects with a fat intake higher than 150 gfat/wk. Extrapolation from these data suggests that a significant increase of dioxin body burden is likely to occur only when dioxin emissions exceed 5 ng TEQ/Nm(3), a threshold considerably above most emissions standards currently in force. [less ▲]

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See detailSurvey of commercial pasteurised cows' milk in Wallonia (Belgium) for the occurrence of polychlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls
Focant, Jean-François ULg; Pirard, Catherine; Massart, Anne-Cécile ULg et al

in Chemosphere (2003), 52(4), 725-733

Congener-specific analyses of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 4 non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 35 ... [more ▼]

Congener-specific analyses of 7 polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs) and 4 non-ortho (coplanar) polychlorinated biphenyls (cPCBs) were performed on 35 samples of commercial long-life pasteurised cows' milk issued from eight different brands available in Walloon supermarkets (Belgium). The observed congener profile was characteristic of milk samples issued from industrialised countries with good inter and intra-brand reproducibility's. The PCDDs to PCDFs ratio was equal to 1.8 in concentration. The toxic equivalent (TEQ based on WHO-TEF) value for PCDD/Fs in all analysed milks was 1.09+/-0.30 pg TEQ/g fat (range 0.86-1.59), which is below the recommended EU non-commercialisation threshold value of 3 pg TEQ PCDD/Fs/g of milk fat. The mean TEQ value including cPCBs was 2.23+/-0.55 pg TEQ/g fat. These PCBs actually contributed for 49+/-8.6% of the total TEQ. Among PCDD/Fs and cPCBs, tetrachloro dibenzo-p-dioxin (TCDD), pentachloro dibenzo-p-dioxin (PeCDD), pentachloro dibenzofurans (PeCDFs) and 3,3',4,4',5-pentachloro biphenyl (PCB-126) were the most important contributors to the TEQ. Estimated daily intake (EDI) due to consumption of such milks was 0.34 pg TEQ/kg of body weight/day for PCDD/Fs and 0.69 pg TEQ/kg of body weight/day when cPCBs were included. [less ▲]

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See detailNew strategy for comprehensive analysis of polybrominated diphenyl ethers, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls by gas chromatography coupled with mass spectrometry
Pirard, Catherine; De Pauw, Edwin ULg; Focant, Jean-François ULg

in Journal of Chromatography. A (2003), 998(1-2), 169-181

A strategy for determination of polybrominated diphenyl ethers, polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyls on fatty matrices has been established. After ... [more ▼]

A strategy for determination of polybrominated diphenyl ethers, polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyls on fatty matrices has been established. After extraction, the proposed method allows the purification and the fractionation of all target groups of compounds in a simple multi-step automated clean-up. Furthermore, their subsequent analysis is carried out using a single benchtop mass spectrometer, in four separate injections. Required sensitivity considering levels found in the environment is attained using electron impact ionisation followed by tandem in time mass spectrometry. The whole method has been evaluated on standard solution and quality control samples consisting of fortified beef fat. Sensitivity, selectivity, accuracy and repeatability were tested with satisfactory results. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailMeasurable impact of an old MSWI on the level of dioxins in free-range chickens and eggs grown in its vicinity
Pirard, C.; Focant, Jean-François ULg; Massart, A. C. et al

in Organohalogen Compounds (2003), 60-65

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