Le benzo[a]pyrène (BaP) est un contaminant environnemental de la famille des hydrocarbures aromatiques polycycliques ayant été classé cancérogène chez l’humain. Cependant, la relation entre l’exposition et les effets est toujours mal documentée. L’objectif de cette thèse était de mieux documenter la relation quantitative entre l’exposition au BaP, l’évolution temporelle des biomarqueurs d’exposition et l’apparition d’altérations biologiques précoces, à partir d’études expérimentales chez le rat. Dans un premier temps, nous avons déterminé l’effet de 4 doses de BaP (0.4, 4, 10 et 40 µmol/kg) sur plusieurs biomarqueurs d’exposition (3- et 7-OHBaP, 4,5- et 7,8-diolBaP, BaPtétrol et 1,6-, 3,6- et 7,8-diones-BaP), les adduits à l’ADN et l’expression de gènes impliqués dans le métabolisme du BaP, la réparation de l’ADN et le stress oxydatif. Le BaP et ses métabolites ont été mesurés dans le sang, les tissus et les excrétas, 8 h et 24 h après l’administration intraveineuse de BaP par chromatographie liquide à ultra haute performance (UHPLC) couplée à la fluorescence. Les adduits à l’ADN ont été quantifiés dans les poumons par immuno-essai en chémoluminescence. L’expression des gènes dans les poumons a été réalisée par PCR quantitative en temps réel (qRT-PCR). Les résultats ont révélé une bonne relation dose-excrétion pour le 3-OHBaP, le 4,5-diolBaP et le 7,8-diolBaP et ils ont également renforcé l’utilité du 4,5-diolBaP comme potentiel biomarqueur du BaP en plus du 3-OHBaP. De plus, l’augmentation dose-dépendante de la formation des adduits et de l’expression de certains gènes impliqués dans le métabolisme et le stress oxydatif a suggéré l’intérêt de ces derniers comme biomarqueurs d’effet précoce. Dans un second temps, nous avons évaluer le profil cinétique des biomarqueurs en lien avec la modulation temporelle de la formation des adduits à l’ADN et de l’expression génique, en utilisant la dose de 40 µmol/kg de BaP telle qu’établie dans l’étude précédente, avec une série de mesures sur une durée de 72 h après l’injection intraveineuse de BaP. Il est apparu que le 3- et le 7-OHBaP ainsi que le 4,5- et le 7,8-diolBaP semblaient être de bons biomarqueurs d'exposition; les hydroxyBaP et diolBaP présentaient des cinétiques différentes, mais tous ces métabolites étaient corrélés de façon significative aux adduits BaPDE dans les poumons. L’expression de certains gènes et l’étude de leur profil cinétique a également permis de faire des liens avec la formation des adduits et de mieux comprendre le métabolisme du BaP. Après ces résultats, il semblait alors logique de s’intéresser à l’effet de la voie d’exposition dans un context d’exposition multiple de la population. Les données mesurées dans le sang et les excréta, après administration de 40 µmol/kg de BaP par voie intraveineuse, intratrachéale, orale, et cutanée, ont encore une fois montré l'intérêt de mesurer plusieurs métabolites pour l’évaluation de l’exposition en raison des différences en fonction de la voie d’administration du composé et des différences dans la cinétique de plusieurs biomarqueurs, notamment entre les hydroxy (3- et 7-OHBaP) et les diols-BaP (4,5- et 7,8-diolBaP). Les résultats suggèrent aussi que la mesure de ratios de concentrations de différents métabolites pourrait aider à indiquer le moment et la principale voie d’exposition. Ces données ont permis une meilleure compréhension du continuum entre l’exposition et les effets. / Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon that has been classified as carcinogenic to humans. However, the relationship between exposure and effect is still poorly documented. The aim of this thesis was to document the quantitative relationship between exposure to BaP, the temporal evolution of biomarkers of exposure and the appearance of early biological alterations, by conducting experimental studies in rats. First, we determined the effect of four doses of BaP (0.4, 4, 10 and 40 µmol / kg) on several biomarkers of exposure (3- and 7-OHBaP, 4,5- and 7,8 -diolBaP, BaPtetrol and 1,6 -, 3,6 - and 7,8-dione-BaP), on DNA adducts and the expression of genes involved in the metabolism of BaP, DNA repair and oxidative stress. BaP and its metabolites were measured in blood, tissues and excreta, 8 h and 24 h after intravenous administration of BaP by ultra high performance liquid chromatography (UHPLC) coupled to fluorescence. The DNA adducts were quantified in lungs by chemiluminescence immunoassay. Gene expression in lungs was achieved by quantitative real time PCR (qRT-PCR). The results showed a good dose-excretion relationship for 3- OHBaP , 4,5- and 7,8- diolBaP and they also showed the usefulness of 4,5- diolBaP as a potential biomarker of BaP in addition to 3- OHBaP. Furthermore, the dose-dependent increase in the formation of adducts and the expression of certain genes involved in metabolism and oxidative stress highlighted the latter as potentially interesting biomarkers of effect. The following study was designed to evaluate the toxicokinetic profile of biomarkers of exposure related to the temporal modulation of the formation of DNA adducts and gene expression, using a dose of 40 µmol/kg BaP as set out in the previous study, but with regular measurements during the 72-h period following intravenous injection of BaP. It appeared that the 3 - and 7- OHBaP and 4,5 - and 7,8- diolBaP seemed to be good biomarkers of exposure; hydroxyBaPs and diolBaPs exhibited different kinetics but all the metabolites were significantly correlated with BaPDE adducts in the lungs. The expression of genes and the study of their kinetic profile also allowed to assess the relationship with the formation of adducts and better understand the metabolism of BaP. Based on these results, it seemed logical to focus on the effect of the route of exposure. The data measured in the blood and excreta after intravenous, intratracheal, oral, and cutaneous administration of 40 mmol/kg BaP have once again demonstrated the importance of measuring several metabolites due to kinetic differences depending on the route of administration of the compound and among biomarkers, in particular between OHBaPs (3 - and 7 - OHBaP) and diolBaPs (4,5 - and 7,8- diolBaP). Results also suggest that measurements of concentration ratios of different metabolites could help indicate the time and the main route of exposure. Overall, these data allowed a better understanding of the continuum between BaP exposure and early effects.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-08-29T12:39:56Z No. of bitstreams: 1 arquivo total.pdf: 2695338 bytes, checksum: a378ea64a8ee3f1da67dc243ed293db5 (MD5) / Made available in DSpace on 2016-08-29T12:39:56Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 2695338 bytes, checksum: a378ea64a8ee3f1da67dc243ed293db5 (MD5) Previous issue date: 2015-05-29 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Despite advances in research oncology field, has been an increased incidence and mortality caused by cancer, consisting in a major public health problem. Literature reports, that Morita-Baylis Hillman adducts (MBHA) show promising biological activities, such as: antiparasitic, against Leishmania, Plasmodium sp. and Trypanosomes, as well as effect on sea urchin embryo development. To assess anticancer and anti-inflammatory potential of three AMBH: A2CN, and A3CN, A4CN, we used various biological models. In MTT assay, the adducts were potentially toxic to eight cancer cell lines tested (HL-60, MOLT-4, K562, K562-Lucena, MCF-7, HT- 29, L929 and B16F10), however A2CN was the most cytotoxic, with IC50 lower for most cells. Acute myeloid leukemia cells, HL-60 and MOLT-4, were more sensitive and A2CN had IC50 22 and 21 μM in these cells. In chronic myelogenic leukemia cells, K562 and Lucena, A2CN presented IC50 of 58 and 60 μM, respectively. A2CN has been less cytotoxic to normal cells in peripheral blood and normal human fibroblasts (FN1), and IC50 was 78 and 126 μM, respectively. The action mechanism induced by A2CN in K562 cells was studied at 15, 30 and 60 μM. The cell viability has not altered when analyzed with propidium iodide, using flow cytometry, showing that A2CN not induced necrosis in these cells. A2CN increased mitochondrial membrane depolarization by 20 % at highest concentration tested. Cytotoxicity of A2CN in K562 cells were related to cell cycle arrest in G1-phase at 15 μM, and Sphase at highest concentration (60 uM) and ROS production increased at the highest concentration tested. Cell cycle arrest in S-phase was related to high expression mRNA of p21, p27 and p53, together with decreased expression of cyclin D1. A2CN also augmented expression of Kv1.3 and Kv3.1 genes in K562 cells treated with 60 μM. In electrophysiological assays, using the whole-cell "patch clamp", A2CN (120 μM) promoted increase total K+ current in K562, and conductance K+ ion was elevated. The potassium channel blocker, 4-aminopyridine (4-AP) (1 mM) decreased the A2CN cytotoxicity in K562 cells analyzed by MTT reduction, indicating that K+ channels have been involved in its cytotoxicity. The in vitro anti-inflammatory activity of A2CN, A3CN and A4CN was evaluated in LPS-stimulated RAW 264.7 macrophages. AMBHs did not reduced cell viability to concentration 20 μM, however, inhibited NO and ROS production induced by LPS. IL-1 β and IL-6 production was completely inhibited by 10 μM of AMBH, but no change in TNF-α levels. Expression of IL-1β and IL-6 genes were also altered by A2CN, A3CN and A4CN, but only A2CN was able to inhibit gene expression of cyclooxygenase-2 (COX-2). Therefore, it can be concluded that A2CN showed be potent anticancer activity, acting on molecular targets that are objects preclinical and clinical studies in oncology, such as p53, p21, p27 and cyclin D1, and proved to be a potent activator of potassium channels. Furthermore, adducts showed remarkable anti-inflammatory potential, a reduction of proinflammatory cytokines such as IL-1 β and IL-6 and COX-2 expression by A2CN. / Apesar dos avanços das pesquisas no campo da oncologia, existe um aumento na incidência do câncer e na mortalidade por esta doença, consistindo em um dos principais problemas de saúde pública. A literatura relata que os Adutos de Morita Baylis-Hillman (AMBH) apresentam atividades biológicas promissoras, tais como: antiparasitária, contra Leishmania sp., Plasmodium sp., e Trypanosoma cruzi, bem como, efeito no desenvolvimento de células embrionárias de ouriço-do-mar. Para avaliar o potencial anticâncer e anti-inflamatório de três AMBH: A2CN, A3CN e A4CN, utilizou-se vários modelos biológicos. Os resultados mostraram que no teste de redução do MTT, os adutos foram potencialmente citotóxicos para as oito linhagens cancerígenas testadas (HL-60, MOLT-4, K562, K562-Lucena, MCF-7, HT- 29, L929, B16F10), contudo A2CN foi o AMBH mais citotóxico, apresentando menor CI50 para a maioria das linhagens. As linhagens de leucemia mielóide aguda HL-60 e MOLT-4 foram as mais sensíveis, e A2CN apresentou CI50 de 22 e 21 μM nestas células. Nas células de leucemia mielóide crônica K562 e Lucena, A2CN apresentou CI50 de 58 e 60 μM, respectivamente. A2CN foi menos citotóxico para as células normais do sangue periférico e para a linhagem de fibroblastos humano normal (FN1), cuja CI50 foi de 78 e 126 μM, respectivamente. O mecanismo de ação de A2CN foi estudado nas células K562, nas concentrações de 15, 30 e 60 μM. A viabilidade da membrana celular não foi alterada, quando analisada com iodeto de propídeo em citômetro de fluxo, mostrando que, a molécula não induziu necrose nestas células. A2CN promoveu um aumento da despolarização da membrana mitocondrial em 20 %, na maior concentração testada, caracterizando um envolvimento da via intrínseca da apoptose. A atividade citotóxica de A2CN em K562 está relacionada à parada no ciclo celular na fase G1, a partir de 15 μM, e na fase S na maior concentração testada de 60 μM. A produção de ROS foi aumentada na maior concentração testada. A parada no ciclo celular na fase S está relacionada com o aumento na expressão do RNAm de p21, p27 e p53 e diminuição na expressão de ciclina D1. A expressão dos genes para Kv1.3 e Kv3.1 também foi aumentada nas células K562, tratadas com 60 μM. Nos ensaios eletrofisiológicos usando a técnica de whole-cell, “patch clamp”, A2CN (120 μM) promoveu um aumento na corrente total de K+ em K562, bem como, aumentou a condutância ao íon K+. O bloqueador de canal de potássio, 4-aminopiridina (4-AP) (1 mM) reduziu a citotoxicidade de A2CN nas células K562, analisadas pela redução do MTT, indicando que os canais de K+ estão envolvidos na citotoxicidade desta molécula. A atividade anti-inflamatória de A2CN, A3CN e A4CN, foi avaliada in vitro na linhagem de macrófagos Raw 264.7, estimulada com (1 μg/ml) de LPS. Os AMBH não reduziram a viabilidade das células até a concentração de 20 μM, contudo inibiram a produção de NO e a produção de ROS induzida pelo LPS a partir da menor concentração dos AMBH, de 2,5 μM. A produção das citocinas IL-1 e IL-6 foi completamente inibida por 10 μM dos AMBH, mas não houve alteração nos níveis de TNF-α. A expressão nos genes das citocinas IL-1 e IL-6, também foram alteradas por A2CN, A3CN e A4CN, porém, apenas A2CN foi capaz de inibir a expressão do gene da Ciclo-oxigenase-2 (COX-2). Isto posto, pode-se concluir que A2CN apresentou potente atividade anticâncer, atuando em alvos moleculares que são objetos de estudos pré-clínicos e clínicos na área oncológica, como p53, p21, p27 e ciclina D1, bem como demonstrou ser um potente ativador de canais de potássio. Além disso, os adutos apresentaram notável potencial anti-inflamatório, com diminuição de citocinas pró-inflamatórias como IL-1 e IL-6, e inibição da expressão de COX-2 por A2CN.

Made available in DSpace on 2015-05-14T13:21:25Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2013817 bytes, checksum: 3393f3576fe03283e4e7fd592df689eb (MD5) Previous issue date: 2013-03-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents microwave irradiation promoting synthetic studies that producing by the first time indolizine-2-carbonitrile (1) and indolizine-2-carboxylate (2) in good to high yields (70% and 81%, respectively) in one step from Morita-Baylis- Hillman adducts (MBHA) 2-(hydroxy(pyridin-2-yl)methyl)acrylonitrile (10) and methyl 2-(hydroxy(pyridin-2-yl)methyl)acrylate (9) respectively. These compounds were subsequently transformed in excellent yields on three 2-indolizine derivatives know in the literature. they are: indolizin-2-yl methanamine (5), 99%, indolizin-2-ylmethanol (6), 100%, indolizine-2-carboxylic acid (3), 100%, in new more three Indolizine, namely : tert-butyl (indolizin-2-ylmethyl) carbonate (7), 99% new, butyl-indolizine-2- carboxylate(4), 94% new, tert-butyl (indolizin-2-ylmethyl)carbamate (8), 86% new. All of the adducts were characterized by infrared physical methods, Gas Chromatography coupled to Mass Spectrometry and Nuclear Magnetic Resonance (1 H NMR and 13 C NMR).All syntheses were developed in this study appropriate industry standards. The reaction activation by microwave irradiation (MO) has been widely used in most synthetic stages of this work, leading to high chemical yields and reduced reaction times. The eight synthesized compounds were in silico designed aiming to present potential selective activities as modulators of ion channels. These activities were suggested by the high score values obtained by using Molinspiration cheminformatics program. / Este trabalho apresenta um estudo sintético promovido por irradiação de micro-ondas, produzindo pela primeira vez a 2-Indolizina-carbonitrila (1) e a 2- Indolizina-carboxilato de metila (2) em bons a altos rendimentos (70% e 81% de rendimentos respectivamente) em uma única etapa, a partir dos Adutos de Morita- Baylis-Hillman (AMBH) 2 (hidroxi(piridin-2-il)metil)acrilonitrila(10) e metil 2- (hidroxi(piridin-2-il)metil)acrilato(9) respectivamente. Estes compostos foram subseqüentemente transformados em excelentes rendimentos em mais três derivados 2-indolizínicos já conhecidos na literatura, a saber: indolizin-2-il metanamina (5), 99%, indolizin-2-il metanol (6), 100%, acido Indolizina-2- carboxílico(3), 100%, e mais três inéditos , a saber: terc-butil (indolizin-2-il metil) carbonato(7), 99% inédito , butil Indolizina-2-carboxilato (4), 94% inédito, e terc-butil (indolizin-2-il metil)carbamato (8), 86% inédito. Todos os Adutos foram caracterizados através dos métodos físicos de Infravermelho, Cromatografia Gasosa acoplada a Espectrometria de Massas e Ressonância Magnética Nuclear (RMN1H e RMN13C). Todas as sínteses neste trabalho foram desenvolvidas em padrões convenientes a indústria. A ativação reacional por irradiação de microondas (MO) foi amplamente utilizada na maioria das etapas sintéticas deste trabalho, conduzindo aos altos rendimentos químicos e aos tempos reacionais reduzidos. Os oito compostos sintetizados foram idealizados in silico objetivando apresentarem potenciais atividades seletivas como moduladores de canais iônicos. Estas atividades foram sugeridas pelos altos valores obtidos de score usando o programa quimioinformático Molinspiration.

This work deals with studying a molecular mechanism of anticancer effect of a new platinum - based drug. The qualities of still unknow dinuclear platinum komplex (BBR3571-DACH) were parallelly studied together with clinically time-tested and used mononuclear platinum complex DACH. Earlier essays demostrated, that DNA is the critical target for the cytostatic activity of platinum compounds. Altered properties of DNA and binding characteristics of these two platinum compounds were monitored by several different bioanalytical methods (differential pulse polarography, UV-VIS spectrophotometry, fluorescence spectrophotometry, CD spectroscopy and electrophoresis) after modification of DNA by both of platinum complexes. For the compounds BBR3571-DACH and DACH it was determined that the DNA binding is rapid and bifunctional. The stabilizing effect on DNA was significant particularly after modification of DNA by dinuclear komplex, while denaturating effect wasn´t proved at all. The results also indicate that dinuclear platinum complex BBR3571-DACH probably does not participate on formation of long-range cross-links like other early studied polynuclear platinum complexes.

The main aim of this work was to compare the genotoxicity of organic extracts from different size fractions of aerosol particles (1-10 µm, 0,5-1 µm, 0,17-0,5 µm) collected by high volume cascade impactors in various localities of the Czech Republic differing in the extent of the environmental pollution (Březno - strip mine, Dobré Štěstí - highway, Praha - city center, Láz - background station). Genotoxicity was determined in acellular assay of calf thymus DNA (CT-DNA) with and without S9 metabolic activation by analysis of DNA adducts induced by extractable organic matter (EOM) from the particulate matter (PM) by 32 P-postlabeling and the ability of extracts to induce oxidative DNA damage was evaluated using the competitive ELISA test. The main finding of this work is that most of the observed genotoxicity is connected with fine particles (<1 µm). The concentration of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) in EOMs indicate that fine fractions bound the highest amount of c-PAHs in all sampling sites. This fact might be related to a higher specific surface of this fraction as compared with a course fraction and a higher mass as compared with a condensational fraction. As for aerosol mass, both fine and condensational fractions are effective carriers of c-PAHs. Similarly, the DNA...

The low redox potential of guanines (G 1.29 V vs. NHE) compared to other nucleobases, makes them potentially susceptible to attack by exogenous and endogenous damaging species. This property of guanine has also been utilized for the development of several anticancer agents including the well-known platinum complexes, cisplatin and carboplatin. The two closely related nickel complexes, NiCR and NiCR-2H, exhibit significant differences in cytotoxicity towards MCF-7 cancer cells. In the first part of this work, we explain this difference using biochemical and biophysical approaches to study their interactions with duplex DNA. The nickel complexes were found to selectively oxidize guanines in bulged DNA structures in the presence of oxidant and notably NiCR-2H oxidizes guanines more efficiently than NiCR. According to 1 H NMR studies, NiCR-2H binds strongly to the N7 position of dGMP compared to NiCR and could be an important oxidation product of NiCR under physiological conditions. The second part of this work focuses on the secondary DNA structures known as G-quadruplex formed in the guanine rich telomeric region. G-quadruplex is formed by stacking of G-quartets (a coplanar cyclic array of four Gs) on top of each other. Its formation is known to inhibit the activity of the reverse transcriptase telomerase that is overexpressed in 80-90% cancer cells. The guanines in telomeric DNA are readily oxidized due to their low redox potential and the major oxidation product is 7, 8-dihydro-8-oxoguanine (OxodG). OxodG (0.58 V vs. NHE) can further be oxidized in the presence of one electron oxidants and the resulting product forms adducts with endogenous nucleophiles such as spermine. In light of these findings, we hereby designed and synthesized novel bifunctional perylene derivatives that can selectively bind to the telomeric DNA via G-quadruplex formation and subsequently react with OxodG in close proximity. These compounds have strong binding affinity towards G-quadruplex and can significantly stabilize the OxodG containing G-quadruplex motif by end stacking on the upper G-quartet. The effect of these compounds on telomerase activity and cytotoxicity towards Hep3B cancer cells was also evaluated.

No description available.

This Thesis extends our fundamental knowledge of high-oxidation-state chemistry and in particular compounds of Xe(VIII), Xe(VI), and Ir(V). The crystal structure of XeVIIIO4 was obtained and provides important information on this fundamentally interesting endothermic and shock-sensitive compound. Macroscopic amounts of XeO3F2 have been prepared for the first time. Although the low-temperature Raman spectrum of solid XeO3F2 exhibits some frequency shifts and band splittings of the bending modes, the spectrum is similar to the Raman spectrum of the previously reported matrix-isolated compound. The crystal structures of decomposition and byproducts resulting from the syntheses of XeO3F2 have been obtained for [XeF5][HF2]∙XeOF4 and XeF2∙XeO2F2. The solid-state structure of xenon trioxide, XeO3, was reinvestigated by low-temperature single-crystal X-ray diffraction and shown to exhibit polymorphism that is dependent on crystallization conditions. The previously reported α-phase (orthorhombic, P212121) only forms upon evaporation of aqueous HF solutions of XeO3. In contrast, two new phases, β-XeO3 (rhombohedral, R3) and gamma-XeO3 (rhombohedral, R3c) have been obtained by slow evaporation of aqueous solutions of XeO3. The extended structures of all three phases result from Xe=O----Xe bridge interactions among XeO3 molecules that arise from the amphoteric donor-acceptor nature of XeO3. The Xe atom of the trigonal pyramidal XeO3-unit has three Xe---O secondary bonding interactions. The orthorhombic α-phase displays the greatest degree of variation among the contact distances and has a significantly higher density than the rhombohedral phases. The ambient-temperature Raman spectra of solid α- and gamma-XeO3 have also been obtained and assigned for the first time. Xenon trioxide interacts with CH3CN and CH3CH2CN to form O3XeNCCH3, O3Xe(NCCH3)2, O3XeNCCH2CH3, and O3Xe(NCCH2CH3)2. Their low-temperature single-crystal X-ray structures show that the xenon atoms are consistently coordinated to three electron-donor atoms which result in pseudo-octahedral environments around their xenon atoms. The adduct series provides the first examples of a neutral xenon oxide bound to nitrogen bases. Energy-minimized gas-phase geometries and vibrational frequencies were obtained for the model compounds O3Xe(NCCH3)n (n = 1−3) and O3Xe(NCCH3)n∙[O3Xe(NCCH3)2]2 (n = 1, 2). The natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), electron localization function (ELF), and molecular electrostatic potential surface (MEPS) analyses were carried out to further probe the nature of the bonding in these adducts. Xenon trioxide forms adducts with the polytopic nitrogen base ligands: hexamine, DABCO, 2,2’-bipyridine, 1,10-phenanthroline, and 4,4’-bipyridine. The adducts were conveniently synthesized in aqueous or CH3CN solutions and are stable at room temperature. The crystal structures of hexamine∙2XeO3, hexamine∙XeO3∙H2O, 2,2’-bipyridine∙XeO3, 1,10-phenanthroline∙XeO3, and 4,4’-bipyridine∙XeO3 have been determined by low-temperature single-crystal X-ray diffraction. The structures consist of XeO3 molecules bridged by the ligands to form extended supramolecular networks with Xe---N bonds which range from 2.634(3) to 2.829(2) Å. Raman spectroscopy was used to characterize and probe the room-temperature stabilities of these adducts. The reaction of 1,4-diazabicyclo[2.2.2]octane (DABCO) with XeO3 in aqueous solutions yields thin, plate-shaped crystals which are severely twinned whereas the reaction of DABCO with XeO3 in the presence of HF forms [DABCOH]2[F2(XeO3)2]∙H2O and [DABCOH2][F][H2F3] which were also characterized by low-temperature X-ray crystallography and Raman spectroscopy. A reversible temperature-dependent phase transition occurred for [DABCOH]2[F2(XeO3)2]∙H2O. The structures of 2,2’-bipy∙XeO3 and 1,10-phen∙XeO3 provide the first examples of noble-gas chelates. The structure of hexamine∙XeO3∙H2O provides the first instance in which a noble-gas centre is coordinated by water. These compounds also represent the first examples of sp2- and sp3-hybridized N---Xe(VI) bonds and are rare examples of noble-gas compounds that are air-stable at ambient temperatures. Adducts between XeO3 and three molar equivalents of the nitrogen bases, pyridine and 4-dimethylaminopyridine (4-DMAP), have been synthesized and characterized. The crystal structures of (C5H5N)3XeO3, {(CH3)2)2NC5H4N}3XeO3∙H2O have been determined by low-temperature single-crystal X-ray diffraction. The reaction of hydrolyzed XeF6 in acetonitrile with pyridine or 4-DMAP afforded [C5H5NH]4[HF2]2[F2(XeO3)2] and [(CH3)2NC5H4NH][HF2]∙XeO3 which were characterized by low-temperature X-ray crystallography and Raman spectroscopy. The structures contain pyridinium cations that are hydrogen bonded to the fluoride coordinated to XeO3 and can be viewed as pyridinium fluoroxenates. The structure of (CH3)2NC5H5N∙XeO3∙H2O contains a water molecule that is hydrogen bonded to two oxygen atoms of two adjacent XeO3 molecules. The pyridine adduct, (C5H5N)3XeO3, was found to be relatively insensitive to shock, whereas the 4-DMAP adduct was extremely shock sensitive. The number of isolable compounds which contain different noble-gas−element bonds is limited for xenon and even more so for krypton. Examples of Xe−Cl bonds are rare and prior to this work, no definitive evidence for a Xe−Br bonded compound existed. The syntheses, isolation, and characterization of the first compounds to contain Xe−Br bonds ([N(C2H5)4]3[Br3(XeO3)3] and [N(CH3)4]4[Br4(XeO3)4]) and their chlorine analogues are described. The bromo- and chloroxenate salts are stable in the atmosphere at room temperature and were characterized in the solid state by Raman spectroscopy, low-temperature single-crystal X-ray diffraction, and in the gas phase by quantum-chemical calculations. They are the only known examples of cage anions that contain a noble-gas element. The Xe−Br and Xe−Cl bonds are weakly covalent and can be viewed as σ-hole interactions, similar to halogen bonds. Xenon trioxide reacts with alkali metal fluorides and chlorides to form a variety of room-temperature stable fluoro- and chloroxenate salts. The reaction of XeO3 with various ratios of KF in water afforded three new compounds. The crystal structures of α-K[F(XeO3)2], β-K[F(XeO3)2], α-K[FXeO3], K2[F2(XeO3)] have been determined. The reaction of XeO3 with aqueous CsF resulted in Cs3[F3(XeO3)2]. The XeVI−F bond lengths range from 2.3520(18) to 2.5927(17) Å. No stable product was isolated when [N(CH3)4]F was the fluoride source, but in the presence of HF, crystals of [N(CH3)4]3[HF2]2[H2F3]∙2XeO3 were obtained. The reaction of KCl with XeO3 in equimolar amounts resulted in the formation of K[ClXeO3] whereas the analogous reaction with CsCl yielded Cs3[Cl3(XeO3)4]. Attempts to synthesize Xe–P and Xe–S bonded compounds were unsuccessful and instead resulted in adducts between XeO3 and O-bases such as the phosphine oxide adduct, {(C6H5)3PO}2XeO3 and dimethylsulfoxide (DMSO) adduct {(CH3)2SO}3(XeO3)2. Although DMSO was found to be resistant to oxidation by XeO3, no significant Xe---S bonding interactions were observed. Acetone was found to be highly resistant to oxidation by XeO3 and forms {(CH3)2CO}3XeO3 at low temperatures. The reaction of pyridine-N-oxide yielded large crystals of (C5H5NO)3(XeO3)2 in which the structure contains short chains in contrast with ((CH3)2SO)3(XeO3)2 whose structure consists of discrete dimers. The reaction of XeO3 with the oxidatively resistant main-group oxide anion source, [N(CH3)4][OTeF5] in CH3CN solvent afforded [N(CH3)4][F5TeOXeO3(CH3CN)2]. Xenon trioxide reacts with potassium hydroxide to form the previously known K4[XeO6]∙2XeO3 salt which was characterized by Raman spectroscopy and low-temperature X-ray crystallography. The reaction of MgO with XeO3 yielded single crystals of [Mg(OH2)6]4[XeO6(XeO3)12O2]∙12H2O, which also contains perxenate-XeO3 interactions. Alkali metal carbonates also incorporate XeO3 into their crystal lattices. Raman spectra of M2[CO3(XeO3)n]∙xH2O (M = Na, K, Rb) were recorded and contain intense bands assigned to the XeO3 stretching modes and very weak bands assigned to the [CO3]2− modes. The reaction of dilute aqueous solutions of XeO3 with RbOH and atmospheric CO2 afforded single crystals of Rb2[CO3(XeO3)2]∙2H2O which were characterized by low-temperature X-ray crystallography. Attempts to incorporate XeO3 into other polyatomic anion salts such as KMnO4, NaClO3, and NaNO3 were unsuccessful. The reaction of IrO2 with XeF6 in aHF provided [Xe2F11][IrF6], whereas the reaction of IrO2 with KrF2 with ClF3 in anhydrous HF solvent provided [ClO2][Ir2F11] and [ClO2][(μ-OIrF4)3]. The structure of [(μ-OIrF4)3]− consists of a six membered Ir3O3 ring with four terminal fluorine atoms on each Ir atom. It was also found that ClF3 forms an adduct with [Xe2F11][HF2] in which the structural parameters of ClF3 are very similar to that of solid ClF3. The [ClO2][Ir2F11] salt provides the first structural information on the [Ir2F11]− anion and the [(μ-OIrF4)3]− anion represents the first isolated iridium oxide fluoride species. / Thesis / Doctor of Philosophy (PhD) / Xenon is a noble-gas element which is located in the far right-hand column of the periodic table and was previously thought to be chemically unreactive and incapable of forming compounds. In 1962, it was shown that xenon reacts with the most reactive compounds, such as elemental fluorine, but the resulting xenon compounds are themselves highly reactive. This Thesis extends the chemistry of some of the most unstable and chemically reactive xenon compounds that are currently known. One such compound, xenon trioxide, tends to easily detonate unless carefully handled. Methods of stabilizing xenon trioxide were developed and its behaviour with compounds which resulted in formation of new xenon compounds was studied. The molecular structures of these compounds were investigated in the solid with particular emphases on their chemical bonding. Iridium is one of the most chemically resistant metals known. Highly reactive xenon and krypton compounds were used synthesize new iridium compounds.

Le benzo-a-pyrène (BaP) est un hydrocarbure aromatique polycyclique (HAP) cancérogène pour l’homme, qui contamine toutes les sphères de notre environnement. Son métabolite, le BaP-7,8-diol-9,10-époxyde (BPDE) est considéré comme son cancérogène ultime. Le BPDE se lie à l’ADN, formant des adduits qui doivent être réparés et qui seraient responsables des dommages à l’ADN et de la cancérogenèse induite par le BaP. Les adduits BPDE-ADN et les dommages à l’ADN (bris simple-brin [BSB] à l’ADN, aberrations chromosomiques [AC], échanges entre chromatides-sœurs [ÉCS] et micronoyaux [MN]) ont été mesurés dans les lymphocytes humains exposés à de faibles concentrations de BaP, provenant de jeunes volontaires non-fumeurs et en santé. Suite à l’exposition au BaP, le niveau d’adduits BPDE-ADN et la fréquence des AC et des MN augmentent significativement, puis diminuent aux concentrations les plus élevées de BaP testées, suggérant une induction du métabolisme de phase II du BaP. Lors de la mesure des ÉCS, nous obtenons une courbe dose-réponse linéaire, indiquant la production d’un autre type de lésions devant être réparées par le système de réparation par recombinaison homologue. Ces lésions pourraient être des bris à l’ADN ou des bases oxydées (8-OH-dG), ce qui est suggéré par l’analyse des corrélations existant entre nos biomarqueurs. Par ailleurs, la comparaison de la courbe dose-réponse des hommes et des femmes montre que des différences existent entre les sexes. Ainsi, les ÉCS, les AC et les MN sont significativement augmentés chez les hommes à la plus faible concentration de BaP, alors que chez les femmes cette augmentation, quoique présente, est non significative. Des différences interindividuelles sont également observées et sont plus importantes pour les adduits BPDE-ADN, les MN et les AC, alors que pour les ÉCS elles sont minimes. Les analyses statistiques effectuées ont permis d’établir que quatre facteurs (niveau d’exposition au BaP, adduits BPDE-ADN, fréquence des AC et nombre de MN par cellule micronucléée) expliquent jusqu’à 59 % de la variabilité observée dans le test des ÉCS, alors qu’aucun facteur significatif n’a pu être identifié dans le test des AC et des MN. L’analyse du mécanisme de formation de nos biomarqueurs précoces permet de suggérer que les bris à l’ADN et les bases oxydées devraient être classées comme biomarqueurs de dose biologique efficace, au sein des biomarqueurs d’exposition, dans le continuum exposition-maladie du BaP, étant donné qu’ils causent la formation des biomarqueurs de génotoxicité (ÉCS, AC et MN). Par ailleurs, le test des AC et des MN ont permis de confirmer l’action clastogénique du BaP en plus de mettre en évidence des effets aneugènes affectant surtout la ségrégation des chromosomes lors de la division cellulaire. Ces effets aneugènes, reliés à l’étape de progression dans la cancérogenèse, pourraient être particulièrement importants puisque l’exposition au BaP et aux HAP est chronique et dure plusieurs années, voire des décennies. La compréhension des mécanismes régissant la formation des biomarqueurs étudiés dans cette étude, ainsi que des relations existant entre eux, peut être appliquée à de nombreux contaminants connus et émergents de notre environnement et contribuer à en évaluer le mode d’action. / Benzo-a-pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) classified as carcinogenic to human, and is present throughout our environment. Metabolic activation of BaP leads to production of BaP-7,8-diol-9,10-epoxide (BPDE), considered as its ultimate carcinogenic metabolite. BPDE can bind to DNA, forming BPDE-DNA adducts at the origin of BaP-induced DNA damage and carcinogenesis. BPDE-DNA adducts and DNA damages (DNA single-strand breaks [SSBs], chromosomal aberrations [CAs], sister chromatid exchanges [SCEs] and micronuclei [MNs]) are measured in human lymphocytes exposed to low BaP concentrations, taken from non-smoking healthy young subjects. Following BaP exposure, BPDE-DNA adduct levels, as well as CA and MN frequencies raise significantly, and then decrease to the higher BaP concentrations tested, suggesting metabolic enzyme saturation or induction of BaP phase II metabolism. As for SCEs test, a linear dose response curve is obtained, suggesting that production of additional DNA lesions requiring homologous recombination repair may occur. These lesions could be DNA breaks or oxidized DNA bases (8-OH-dG), as indicated by correlation analysis performed between our biomarkers. Additionally, when comparing the dose-response curves for men and women separately, some differences show up. Indeed, SCEs, CAs, and MNs are significantly increased in men at the lowest BaP concentration tested, while in women, this increase is present but not significant. Interindividual differences are also present and are more considerable for BPDE-DNA adducts, MNs and CAs, whereas they are very low for SCEs. Statistical analysis showed that four factors (BaP exposure level, BPDE-DNA adducts, CA frequency and number of MN per micronucleated cell) significantly explained up to 59 % of observed variability in SCE test, while no such factors could explain the observed variability in CA and MN test. Following analysis of mechanisms underlying the formation of early biomarkers, we suggest a modification of the Exposure-Disease Continuum of BaP. We propose that DNA breaks and oxidized DNA bases should be classified as biomarkers of biologically effective dose (part of the exposure biomarkers), as their presence are at origin of early biomarkers of genotoxicity (SCEs, CAs and MNs). On the other hand, CA and MN tests confirmed clastogenic properties of BaP, and highlighted aneugenic effects influencing mostly chromosome segregation during cell division. These aneugenic effects, linked to the progression step of carcinogenesis, could be of particular importance given that exposure to BaP and other PAHs (smoking, occupational exposure) are chronic and may last for decades. Understanding the mechanisms playing a role in early biomarkers formation, as well as the relations existing between them, can be largely applied in our environment to many known and emerging contaminants, thus contributing to characterize their mode of action.

Nitroaromatic compounds are mutagenic and carcinogenic substances present in environment. Most of nitroaromatic compounds are potent mutagens in bacterial and mammalian systems. They are also carcinogens causing development of tumors, primarily in the liver, lung and mammary glands. 3-Nitrobenzanthrone (3-NBA, 3-nitro-7H-benz [de] anthracene-7-one) is one of the polycyclic aromatic nitro compounds possesing high toxic effects. 3-NBA is an environmental pollutant present in diesel exhaust and was also detected in soil and in rain water. 2-Nitrobenzanthrone (2-NBA, 2-nitro-7H-benz [de] anthracene-7-one) is an isomer 3-NBA, which also occurs as a pollutant in air. Although the 2-NBA is a weakly toxic substance, its high abundance in air could exhibit a high health risk to humans. This thesis investigates the metabolism of 3-NBA and its isomeric derivate, isomer 2 NBA, under anaerobic and aerobic conditions. To study the metabolism of these compounds, microsomal systems isolated from the liver of rats pretreated with Sudanem I, -naphthoflavone, phenobarbital, ethanol and pregnenolon 16-carbonitrile (PCN), the inducers of cytochromes P450 1A, 2B, 2E1 and 3A, were used. We also used mouse models, a control mouse line (wild type WT) and mice with deleted gene of NADPH:CYP reductase in the liver, thus absenting...