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9. Electrospray ion chromatography-tandem mass spectrometry of bromate at sub-ppb levels in water

Author

Charles, L., Pepin, D., and Casetta, B.

Subjects
Chromatographic analysis -- Methods, Mass spectrometry -- Usage, Ions -- Analysis, Water -- Analysis, Bromides -- Analysis, Chemistry
Abstract

An electrospray ion chromatography - tandem mass spectrometry (IC-MS/MS) method has been developed for the analysis of bromate ions in water. This IC-MS/MS method improves the limit of detection of bromate ions by a factor of 10. The method consists of solid phase extraction with an ion exchange column and elution of the analyte with water/methanol ammonium sulfate eluent online with a negative ion electrospray mass spectrometry detection. SPE requires sample pretreatment to remove any major ions that displace bromate, consisting of eliminating S[[O.sub.4].sup.2-], [Cl.sup.-], and HC[[O.sub.3].sup.-] ions respectively with barium-form, silver-form, and acid ([H.sup.+]-form) exchange resins. The methanolic sulfate eluent permits IC-MS coupling via an electrospray interface. Br[[O.sub.3].sup.-] was selected in the first quadrupole (Q1) at two m/z values, 127 and 129, according to the isotope contributions of 79Br and 81Br. After fragmentation in the collision cell (second quadrupole, Q2), the third quadrupole (Q3) analyzes the product ions as [(M - O).sup.-], [(M - 20).sup.-], and [(M - 30).sup.-]. Among the six recordable transitions, four were selected, the other two yielding high background. A lowered resolution raised sensitivity by a factor of up to 3. The limit of quantitation of this method was 0.1 [[micro]gram]/L.

Published
1996

20. Effect of p53 activity on the sensitivity of human glioblastoma cells to PARP-1 inhibitor in combination with topoisomerase I inhibitor or radiation

Author

Sabbatino, F., Fusciello, C., Somma, D., Pacelli, R., Poudel, R., Pepin, D., Leonardi, A., Carlomagno, C., Della Vittoria Scarpati, G., Ferrone, S., Pepe, Stefano, Francesco, Sabbatino, Celeste, Fusciello, Domenico, Somma, Pacelli, Roberto, Ravin, Poudel, David, Pepin, Leonardi, Antonio, Carlomagno, Chiara, Giuseppina Della Vittoria, Scarpati, Soldano, Ferrone, and Stefano, Pepe

Subjects
Ionizing, Histology, DNA Repair, Type I, Poly (ADP-Ribose) Polymerase-1, Combinatorial strategy, Poly(ADP-ribose) Polymerase Inhibitors, Article, Cell Line, Cell Line, Tumor, Radiation, Ionizing, Antineoplastic Combined Chemotherapy Protocols, Humans, Cell Proliferation, P53, Tumor, Radiation, Radiotherapy, Cell Cycle, Cell Biology, Flow Cytometry, Combined Modality Therapy, human glioblastoma cell lines, PARP inhibitor, DNA Topoisomerases, Type I, Quinazolines, Glioblastoma, Topotecan, DNA Damage, Topoisomerase I Inhibitors, Tumor Suppressor Protein p53, 2734, DNA Topoisomerases
Abstract

Poly (ADP-Ribose) polymerase-1 (PARP-1) is involved in the DNA repairing system by sensing and signaling the presence of DNA damage. Inhibition of PARP-1 is tested in combination with DNA damaging agents such as topoisomerase I inhibitors or ionizing radiations (RT) for the treatment of glioblastoma (GBM). Disruption of p53, widely prevalent in GBMs, plays a major role in DNA repairing system. The current study investigates whether p53 activity has an effect on the sensitivity of human GBM cells to PARP-1 inhibitors in combination with topoisomerase I inhibitor topotecan (TPT) and/or RT. Human GBM cell lines carrying a different functional status of p53 were treated with PARP-1 inhibitor NU1025, in combination with TPT and/or RT. Cytotoxic effects were examined by analyzing the antiproliferative activity, the cell cycle perturbations, and the DNA damage induced by combined treatments. PARP inhibition enhanced the antiproliferative activity, the cell cycle perturbations and the DNA damage induced by both TPT or RT in GBM cells. These effects were influenced by the p53 activity: cells carrying an active p53 were more sensitive to the combination of PARP inhibitor and RT, while cells carrying an inactive p53 displayed a higher sensitivity to the combination of PARP inhibitor and TPT. Our study suggests that p53 activity influences the differential sensitivity of GBM cells to combined treatments of TPT, RT, and PARP inhibitors. © 2014 International Society for Advancement of Cytometry.

Published
2014

47. Effects of Humic Substances and Phenolic Compounds on the In VitroToxicity of Aluminium

Author

Sauvant, M.P., Pepin, D., and Guillot, J.

Abstract

The effects of natural chelators [humic acids (HA), caffeic acid (CFA), p-coumaric acid (PCA), protocatechuic acid (PA), vanillic acid (VA), salicylic acid (SA), and 4-hydroxyacetophenone (HY)] and effects of well-known chelators [EDTA and citric acid (CA)] on the in vitrotoxicity of aluminium (Al) were investigated with the L-929 murine, Vero simian, and MRC-5 human cell lines. Moderate in vitrocytotoxic effects were induced by Al on the three cell lines (IC50values ranking from 5.6 to 7.6 mM). Furthermore, an increased toxicity was observed when Al was concurrently administered with CA, SA, VA, PCA, and HY. Inversely, significant cytoprotective effects were noted with EDTA, HA, CFA, and PA. The role of chelators, and especially the position and the number of reactive moieties of the phenolic compounds tested, can be highlighted to explain the different toxicological Al behavior observed.

Published
1999
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49. Antigenic relatedness between phospholipases A 2from Naja najavenom and from mammalian cells

Author

Masliah, J., Kadiri, C., Pepin, D., Rybkine, T., Etienne, J., Chambaz, J., and Bereziat, G.

Abstract

Polyclonal antiserum was prepared against phospholipase A 2from Naja najaand used to prepare a purified antibody. It cross-reacted with the antigen, and with intracellular mammalian PLA 2. This antibody was immunoreactive and inhibited the PLA 2activity of Naja najaand of guinea pig alveolar macrophages or rat lymphocytes. By immunoblotting, this antiserum revealed one band of PLA 2from Naja naja(14 kDa) and 3 bands for guinea pig alveolar macrophages and rat lymphocytes (30, 45 kDa and a minor band of 14 kDa). These results show an antigenic relatedness between an extracellular PLA 2and membrane-bound PLA 2from two different mammalian species and cell types.

Published
1987
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50. Etude du conditionnement d'une eau minérale en récipient de polyéthylène téréphtalate

Author

Pepin, D, Communal, P.Y., and Dupire, B.

Abstract

La qualité des eaux embouteillées en récipients de matière plastique peut être par des composés générateurs de goût. Le polyéthylène téréphtalate (PET) est un polymère dont la dégradation conduit à la formation d'acétaldéhyde qui confère à l'eau un goût prononcé.Le dosage de l'acétaldéhyde jumelé à une étude organoleptique, au cours d'un test de compatibilité du PET et d'une eau minérale carbo-gazeuse, a permis de mettre en évidence l'intérêt du dosage de l'acétaldéhyde dans le matériau et la nécessité de recourir à une modélisation dans l'impossibilité de fixer des conditions expérimentales incontestables pour ce type de test.

Published
1983
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