References of "De Pauw, Edwin"
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See detailOptoacoustic specific detection of prostate cancer using functionalized gold nanorods
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, October 10)

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See detailConformationally driven gas-phase H/D exchange of dinucleotide negative ions
Balbeur, Dorothée ULg; Dehareng, Dominique ULg; De Pauw, Edwin ULg

in Journal of the American Society for Mass Spectrometry (2007), 18(10), 1827-1834

Gas-phase hydrogen/deuterium exchange of six deprotonated dinucleoticles with CD3OD was performed in the second hexapole of a Fourier transform ion-cyclotron resonance (FTICR) mass spectrometer. To ... [more ▼]

Gas-phase hydrogen/deuterium exchange of six deprotonated dinucleoticles with CD3OD was performed in the second hexapole of a Fourier transform ion-cyclotron resonance (FTICR) mass spectrometer. To complete these experiments, dynamic simulations were carried out to investigate the different conformations adopted by the dinucleotides. In the experimental conditions and in integrating the experimental and theoretical results, H/D exchange was shown to be controlled by hydrogen accessibility and not by the chemical nature of the heteroatom bearing the exchangeable hydrogen. A model including simultaneous H/D exchanges at the experimental time scale was used to reproduce the dinucleotide H/D exchange kinetic plots. The relay mechanism was not relevant for dinucleotides. This allowed the H/D exchange rates to be directly linked to conformations. [less ▲]

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See detailExploring the Formation Pathways of DNA G-Quadruplex Architectures
Rosu, Frédéric ULg; Poncelet, Harmonie; Teulade-Fichou, Marie-Paule et al

Conference (2007, September 07)

Guanine-rich DNA strands can form the so-called G-quadruplex architectures due to the formation of quartets of guanines linked by 8 hydrogen bonds. G-quadruplexes are further stabilized by the inclusion ... [more ▼]

Guanine-rich DNA strands can form the so-called G-quadruplex architectures due to the formation of quartets of guanines linked by 8 hydrogen bonds. G-quadruplexes are further stabilized by the inclusion of cations between the G-quartets. The abundance of G-rich regions throughout the genome and their very presence in telomeric regions made G-quadruplexes interesting targets. NMR and crystallographic studies of G-quadruplex structures revealed amazing variety in the G-quadruplex topologies. The next challenge will be to understand the rules governing the formation of the various topologies, in order to predict relevant G-quadruplexes in the genome, and in order to act rationally on their formation or disruption. To date, only few experimental [1] or theoretical [2] studies have been devoted to investigating the mechanisms of G-quadruplex formation. We report here a detailed investigation of DNA G-quadruplex formation pathways using electrospray mass spectrometry (ESI-MS). The sequences TGnT (n = 3-6) were purchased from Eurogentec (Seraing, Beliugm). ESI-MS experiments were performed in the negative ion mode on a Q-TOF Ultima Global (Waters, Manchester, UK). The cation used was ammonium (up to 150 mM). Experiments were performed in the presence and absence of methanol (up to 20%) as co-solvent. ESI-MS allows counting both the number of strands and the number of cations in each intermediate. We could confirm the presence of transient dimer and trimer intermediates in low abundance. More unexpectedly, ESI-MS also reveals unambiguously the formation of pentamers which contain ammonium cations. The pentamers slowly convert into tetramers. Counting the number of included cations also revealed that, in the case of (TG6T)4, inclusion of four ammonium cations is fast, while the inclusion of the last ammonium ion is very slow. We also found that the addition of methanol (initially added to obtain higher ion intensities) significantly increases the rate of G-quadruplex formation. Finally, we also investigated the role of G-quadruplex ligands in the rate of formation of G-quadruplexes. We could classify the ligands according to their increase of G-quadruplex formation kinetics, and distinguish the intermediates. Interestingly, one ligand showed formation of a higher-order structure by bridging two G-quadruplexes. Acknowledgement: The authors thank the FRS-FNRS for their support. References: [1] J. Gros et al., Nucleic Acids Res., 2007, doi:10.1093/nar/gkm111. [2] R. Stefl et al., Biophys. J., 2003, 85(3), 1787-1804. [less ▲]

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See detailDevelopment of a new integrated biosensor system for an accurate diagnosis of prostate cancer using optoacoustic detection
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, June 09)

The prostate cancer is the most common male-specific cancer observed in the European Union and is the second leading cause of cancer death in men in our industrialized countries. The choice of treatment ... [more ▼]

The prostate cancer is the most common male-specific cancer observed in the European Union and is the second leading cause of cancer death in men in our industrialized countries. The choice of treatment and its efficiency is largely dependent on the stage and on the degree of advancement of the cancer when it is diagnosed. Screening procedures like digital rectal examination (DRE) and free prostate specific antigen (PSA) level testing are well established but lack accuracy, yielding only 80% of prostate cancers diagnosed in an early stage. By providing a more accurate and precise tool for diagnosing prostate cancer in its early stages, the percentage of curable cancer patients would increase radically. Current imaging techniques have limited value, thus a major challenge in current prostate cancer oncology is to develop more accurate imaging assessments. An efficient imaging technique which significantly improves the sensitivity and specificity of diagnosing, staging and predicting the behaviour of prostate cancer would be extremely valuable. The ADONIS Project intends to prove the concept of using optoacoustic imaging in combination with biologically functionalized nanoparticles as an integrated biosensor based system for the production of specific and sensitive data for accurate diagnosis of prostate cancer. The achievement of this objective requires excellent know-how on a variety of scientific and technologic fields, brought by the partners of ADONIS, coming from five European countries, such as laser and ultrasound technologies and image reconstruction techniques, the bio-functionalization of nanoparticles, the system integration and, finally, experiments and competent evaluation of the results for their application potential. The development of the biosensor is firstly performed to target the Prostate Specific Membrane Antigen (PSMA), a transmembrane protein considered as a suitable biomarker for prostate cancer and which is under intense investigation for use as an imaging and therapeutic target. To allow the detection optimization of the biosensor, a 3D cellular culture technique (Rotating Cell Culture System) is developed with LNCaP cells (a human prostate carcinoma cell line reported to express PSMA) to be closest to the in vivo aspect for which a three-dimensional aspect of tumor for the biosensor detection is needed. Detection and localisation of PSMA on LNCaP cell surface was performed by immunostainning on monolayer culture and on spheroid slices. Then, by backscattered electron (BSE) microscopy analysis, detection of nanoparticles on cells surface shows the successful binding of the biosensor to the cells expressing PSMA. In prospect, the detection of the biosensor will be tested on large spheroids and finally tested on in vivo model. [less ▲]

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See detailDevelopment and validation of a multi-residue method for pesticide determination in honey using on-column liquid-liquid extraction and liquid chromatography-tandem mass spectrometry
PIRARD, Catherine ULg; Widart, Joëlle ULg; Nguyen, Bach Kim ULg et al

in Journal of Chromatography. A (2007), 1152(1-2), 116-123

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran ... [more ▼]

We report on the development and validation under ISO 17025 criteria of a multi-residue confirmatory method to identify and quantify 17 widely chemically different pesticides (insecticides: Carbofuran, Methiocarb, Pirimicarb, Dimethoate, Fipronil, Imidacloprid; herbicides: Amidosulfuron, Rimsulfuron, Atrazine, Simazine, Chloroturon, Linuron, Isoxaflutole, Metosulam; fungicides: Diethofencarb) and 2 metabolites (Methiocarb sulfoxide and 2-Hydroxytertbutylazine) in honey. This method is based on an on-column liquid liquid extraction (OCLLE) using diatomaceous earth as inert solid support and liquid chromatography (LC) coupled to mass spectrometry (MS) operating in tandem mode (MS/MS). Method specificity is ensured by checking retention time and theoretical ratio between two transitions from a single precursor ion. Linearity is demonstrated all along the range of concentration that was investigated, from 0.1 to 20 ng g(-1) raw honey, with correlation coefficients ranging from 0.921 to 0.999, depending on chemicals. Recovery rates obtained on home-made quality control samples are between 71 and 90%, well above the range defined by the EC/657/2002 document, but in the range we had fixed to ensure proper quantification, as levels found in real samples could not be corrected for recovery rates. Reproducibility is found to be between 8 and 27%. Calculated CC alpha and CC beta (0.0002-0.943 mg g(-1) for CC alpha, and 0.0002-1.232 ng g(-1) for CCP) show the good sensitivity attained by this rnulti-residue analytical method. The robustness of the method has been tested in analyzing more than 100 raw honey samples collected from different areas in Belgium, as well as some wax and bee samples, with a slightly adapted procedure. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailTop-Down Proteomics using Matrix-Enhanced ISD
Demeure, Kevin ULg; Quinton, Loïc ULg; Gabelica, Valérie ULg et al

Conference (2007, June 05)

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See detailAn immuno-PF2D-MS/MS proteomic approach for bacterial antigenic characterization: To Bacillus and beyond
Ruelle, Virginie ULg; Falisse-Poirier, Nandini; Elmoualij, Benaïssa ULg et al

in Journal of Proteome Research (2007), 6(6), 2168-2175

We are confronted daily to unknown microorganisms that have yet to be characterized, detected, and/ or analyzed. We propose, in this study, a multidimensional strategy using polyclonal antibodies ... [more ▼]

We are confronted daily to unknown microorganisms that have yet to be characterized, detected, and/ or analyzed. We propose, in this study, a multidimensional strategy using polyclonal antibodies, consisting of a novel proteomic tool, the ProteomeLab PF2D, coupled to immunological techniques and mass spectrometry ( i-PF2D-MS/MS). To evaluate this strategy, we have applied it to Bacillus subtilis, considered here as our unknown bacterial model. [less ▲]

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See detailGlobal strategy for the development of estrogenic compounds detection screening test
Collodoro, Mike ULg; Makasinga, Elu; Lemaire, Pascale ULg et al

Poster (2007, May)

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See detailIdentification of specific reachable molecular targets in human breast cancer using a versatile ex vivo proteomic method
Castronovo, Vincenzo ULg; Kischel, Philippe ULg; Guillonneau, Francois et al

in Proteomics (2007), 7(8), 1188-1196

Targeting of tumoral tissues is one of the most promising approaches to improve both the efficacy and safety of anticancer treatments. The identification of valid targets, including proteins specifically ... [more ▼]

Targeting of tumoral tissues is one of the most promising approaches to improve both the efficacy and safety of anticancer treatments. The identification of valid targets, including proteins specifically and abundantly expressed in cancer lesions, is of utmost importance. Despite state-of-the-art technologies, the discovery of cancer-associated target proteins still faces the limitation, in human tissues, of antigen accessibility to suitable high-affinity ligands such as human mAb bound to bioactive molecules. Terminal perfusion of tumor-bearing mice or ex vivo perfusion of human cancer-bearing organs with a reactive biotin ester solution has successfully led to the identification of novel accessible biomarkers. This methodology is however restricted to perfusable organs, and excludes most of the tissues of interest to targeted therapies, e.g. primary breast cancer and metastases. Herein, we report on the development of a new chemical proteomic method that bypasses the perfusion step and thus offers the potential to identify accessible molecular targets in virtually all types of animal and human tissues. We have validated our new procedure by identifying biomarkers selectively expressed in human breast carcinoma. Overall, this powerful technology may lay the ground not only for custom-made therapies in cancer, but also for the development of therapies that need to be selectively delivered in a specific tissue. [less ▲]

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See detailOverview on the ADONIS Project: Accurate Diagnosis of prostate cancer using Optoacoustic detection of biologically functionalized gold Nanoparticles - A new Integrated Biosensor System
Fleron, Maximilien ULg; Schol, Daureen ULg; Greisch, Jean-François et al

Poster (2007, March 21)

Overview on the ADONIS Project: Accurate Diagnosis of prostate cancer using Optoacoustic detection of biologically functionalized gold Nanoparticles - A new Integrated Biosensor System

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See detailMitoproteome plasticity of rat brown adipocytes in response to cold acclimation
Navet, Rachel ULg; Mathy, Grégory ULg; Douette, Pierre ULg et al

in Journal of Proteome Research (2007), 6(1), 25-33

Cold acclimation induces an adaptative increase in respiration in brown adipose tissue (BAT). A comparative analysis by two-dimensional differential in-gel electrophoresis of mitochondrial protein ... [more ▼]

Cold acclimation induces an adaptative increase in respiration in brown adipose tissue (BAT). A comparative analysis by two-dimensional differential in-gel electrophoresis of mitochondrial protein patterns found in rat control and cold-acclimated BAT was performed. A total of 58 proteins exhibiting significant differences in their abundance was unambiguously identified. Proteins implicated in the major catabolic pathways were up-regulated as were ATP synthase and mitofilin. Moreover, these results support the fact that adipocytes can balance their ATP synthesis and their heat production linked to UCP1-sustained uncoupling. [less ▲]

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See detailAbsorption, disposition and excretion of polybrominated diphenyl ethers (PBDEs) in chicken
Pirard, Christian ULg; De Pauw, Edwin ULg

in Chemosphere (2007), 66(2), 320-325

Except for fish, no toxicokinetic data on polybrominated diphenyl ethers (PBDEs) is available on relevant animals for the human food chain. In the present work, absorption, elimination through eggs and ... [more ▼]

Except for fish, no toxicokinetic data on polybrominated diphenyl ethers (PBDEs) is available on relevant animals for the human food chain. In the present work, absorption, elimination through eggs and disposition of PBDEs in laying chickens were studied and compared to dioxin behaviour. Hens were fed with diet containing 3.4 mg/kg feed of PBDEs and 0.95 ng TEQ/kg feed of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs). PBDEs have been demonstrated to show drastically different behaviours from PCDD/Fs and dioxin-like compounds. Excretion of PBDEs increased for two weeks and then decreased to nearly 0%. Sixty-two percent of ingested 2,2',4,4'-tetraBDE (BDE-47) were found in excreta after two weeks, suggesting a reductive debromination of PBDEs in the digestive tract. PBDE level in eggs increased during five weeks and reached 24 microg/g fat. After then, levels decreased to 3 microg/g fat at the end of the trial. PBDE bioconcentration factors estimated for abdominal fat varied from 0.7 for BDE-47 to 2 for BDE-183. [less ▲]

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See detailRational selection of the optimum MALDI matrix for top-down proteomics by in-source decay
Demeure, Kevin ULg; Quinton, Loïc ULg; Gabelica, Valérie ULg et al

in Analytical Chemistry (2007), 79(22), 8678-8685

in-source decay (ISD) in MALDI leads to c- and z-fragment ion series enhanced by hydrogen radical donors and is a useful method for sequencing purified peptides and proteins. Until now, most efforts to ... [more ▼]

in-source decay (ISD) in MALDI leads to c- and z-fragment ion series enhanced by hydrogen radical donors and is a useful method for sequencing purified peptides and proteins. Until now, most efforts to improve methods using ISD concerned instrumental optimization. The most widely used ISD matrix is 2,5-dihydroxybenzoic acid (DHB). We present here a rational way to select MALDI matrixes likely to enhance ISD for top-down proteomic approaches. Starting from Takayama's model (Takayama, M. J. Am. Soc. Mass Spectrom. 2001, 12, 1044-9), according to which formation of ISD fragments (c and z) would be due to a transfer of hydrogen radical from the matrix to the analyte, we evaluated the hydrogen-donating capacities of matrixes, and thus their ISD abilities, with spirooxazines (hydrogen scavengers). The determined hydrogen-donating abilities of the matrixes are ranked as follows: picolinic acid (PA) > 1,5-diaminonaphtalene (1,5-DAN) > DHB > sinapinic acid > alpha-cyano-4-hydroxycinnamic acid. The ISD enhancement obtained by using 1,5-DAN compared to DHB was confirmed with peptides and proteins. On that basis, a matrix-enhanced ISD approach was successfully applied to sequence peptides and proteins up to similar to 8 kDa. Although PA alone is not suitable for peptide and protein ionization, ISD signals could be further enhanced when PA was used as an additive to 1,5-DAN. The optimized matrix preparation was successfully applied to identify larger proteins by large ISD tag researches in protein databases (BLASTp). Coupled with an adequate separation method, ISD is a promising tool to include in a top-down proteomic strategy. [less ▲]

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See detailDiscovery of a natural thiamine adenine nucleotide
Bettendorff, Lucien ULg; Wirtzfeld, Barbara; Makarchikov, Alexander F et al

in Nature Chemical Biology (2007), 3(4), 211-212

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine ... [more ▼]

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine triphosphate (AThTP, 1), or thiaminylated ATP. We discovered AThTP in Escherichia coli and found that it accumulates specifically in response to carbon starvation, thereby acting as a signal rather than a cofactor. We detected smaller amounts in yeast and in plant and animal tissues. [less ▲]

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See detailData quality of the serum analysis of PCDD, PCDF and PCB in the French dioxin and incinerators study
Pascal, M.; Eppe, Gauthier ULg; Zeghnoun, A. et al

in Organohalogen Compounds (2007), 69

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