La glycosylation est un processus enzymatique permettant l'ajout de sucres à des composés (sucres, lipides ou protides), modifiant ainsi leurs propriétés. La glycosylation est impliquée dans la détoxification des xénobiotiques et des variations d'activité des enzymes responsables ont été identifiées comme facteur de risque de cancer en particulier dans les organes exposés aux xénobiotiques. Dans la première partie de notre travail nous étudions l'impact des polymorphismes génétiques de certaines enzymes responsables de la détoxification (UGT1A7, GST et XRCC1) sur le risque de carcinome hépatocellulaire. Nous montrons que la combinaison de certains polymorphismes génétiques peut entraîner une augmentation du risque de CHC. Des modifications d'expression des glycoprotéines de surface ont été observées dans les cellules cancéreuses jouant un rôle dans leurs interactions avec le microenvironnement. Dans la seconde partie, nous étudions l'effet de l'inhibition des interactions des cellules de CHC/cellules endothéliales par le blocage du couple sialyl Lewis x/E-sélectine sur la croissance tumorale. Ce blocage est obtenu, d'une part par transfert du gène de la Fucosyl-transferase I, inhibant l'expression de sLex à la surface des cellules de CHC, et d'autre part, par utilisation de cimétidine ou d'amiloride permettant une inhibition de l'expression de la E-sélectine par les cellules endothéliales. Nous obtenons une inhibition de la croissance tumorale in vivo par blocage de la néoangiogénèse. Ces travaux permettent donc d'identifier des facteurs de risque génétiques de CHC et d'envisager une autre voie de traitement du CHC. / Glycosylation is an enzymatic process that consists of the addition of glycosyl groups to compounds (sugars, lipids or proteins), thus modifying their properties. Glycosylation is involved in the detoxification of xenobiotics and variations in activity of enzymes responsible have been identified as a potential risk factor for cancer in particular in organs in contact with the external environment. In the first part of our work we study the impact of polymorphisms of detoxification enzyme (UGT1A7, GST and XRCC1) on the risk of hepatocellular carcinoma. We show that the combination of genetic polymorphisms of such enzymes may increase the risk of HCC. Modifications in the expression of surface glycoproteins have been observed in cancer cells and play a role in their interactions with the tumoral microenvironment. In the second part, we study the effect of inhibition of interactions of HCC cells / endothelial cells on tumor growth by blocking the interaction between sialyl Lewis x and E-selectin. First, we achieved the inhibition of the expression of sLex on the surface of HCC cells by introducing fucosyl transferase- I gene in HCC cells. In a second part of our work we used cimetidine and amiloride to inhibit the expression of E-selectin by endothelial cells. This approach resulted in inhibition of HCC cells / endothelial cells interaction and thereby tumor growth inhibition in vivo. This effect is mediated by an inhibition of tumor neoangiogenesis. This work therefore identifies genetic risk factors for HCC and allows considering another way of treatment of HCC.

No presente trabalho foram realizados estudos de regiosseletividade das reações de abertura de 2,3-epoxipropanoato de etila (1) utilizando diferentes nucleófilos de selênio e algumas dessas reações foram desenvolvidas com a adição do ácido de Lewis trifluoreto de boro dietil éter (BF3·Et2O). A abertura desse oxirano ao utilizar os nucleófilos MeSeMgCl e MeSeLi-BF3·Et2O ocorreu seletivamente no Carbono C-3 formando o composto de interesse (3-metilseleno 2-hidroxipropanoato de etila), já ao utilizar MeSeLi (em ausência ácido de Lewis) a abertura procedeu-se seletivamente no carbono C-2 formando 2-metilseleno-3-hidroxipropanoato de etila. A reação com o nucleófilo (Na[PhSeB(OEt)3]) levou à mistura desses regioisômeros. O ácido de Lewis BF3·Et2O em presença do selenolato levou a inversão de regiosseletividade da reação de abertura do epóxido 1 e a razão estequiométrica de BF3·Et2O adicionada ao meio reacional correspondeu, proporcionalmente, a porcentagem de obtenção do produto de abertura em C-3 (Tabela 1). Os resultados obtidos sugeriram que BF3·Et2O altera a nucleofilicidade do selenolato (RMN de 77Se) a partir de uma interação selênio-boro. A formação da ligação Se-B pode ocorrer com ou sem a liberação de fluoreto e esse mecanismo foi investigado por meio do emprego de uma sonda fluorescente seletiva desse haleto. O mecanismo dessas reações também foram investigados por cálculos teóricos, os quais mostram-se totalmente coerentes com os resultados experimentais. / In the present work was studied reactions of regioselective opening of 2,3-epoxyester using different selenolatos and some of this reactions were developed by adding Lewis acid BF3·Et2O. The opening reaction of this oxirane using the nucleofilms MeSeMgCl and MeSeLi-BF3·Et2O occurred selectively in carbon C-3 forming the compound of interest (ethyl 3-methylselene 2-hydroxypropanoato of ethyl), already using MeSeLi (in Lewis acid absence) the reaction was selectively on C-2 carbon to form ethyl 2-methylselene-3-hydroxypropanoate. The reaction with the nucleophile (Na[PhSeB(OEt)3]) formed a mixing of these regioisomers. The Lewis acid BF3·Et2O in presence of selenolate reverses the regioselectivity of opening epoxide (1) reaction and the stoichiometric value of BF3·Et2O added in the reaction corresponded proportionally with the percentage of C-3 product (Table 1). The results suggested that BF3·Et2O alters the nucleophilicity of selenolate (77Se NMR) from a selenium-boron interaction. Se-B bond formation may occur with or without fluoride release and this mechanism has been investigated by the use of a selective fluorescent probe of that halide. The mechanism of these reactions was also investigated by theoretical calculations, which are fully consistent with the experimental results.

Kationische Zinkkomplexe werden als katalytisch aktive Spezies zahlreicher Lewis-Säure-katalysierter Reaktionen vermutet. Die diesen Katalysereaktionen zugrunde liegenden Mechanismen sind jedoch unzureichend verstanden. Das Ziel der vorliegenden Dissertation ist die Synthese strukturell definierter kationischer Zinkorganyle als Modellverbindungen für katalytisch aktive Spezies zinkkatalysierter Reaktionen. Der Fokus liegt auf Zinkverbindungen mit Cyclopentadienylliganden (Cp-Liganden), da Cp-Liganden ungewöhnliche Bindungssituationen stabilisieren können. In dieser Arbeit wird die erfolgreiche Synthese und Charakterisierung mehrerer kationischer Zinkkomplexe des Pentamethylcyclopentadienylliganden (Cp*-Liganden) beschrieben. Ein gemeinsames Strukturmerkmal dieser Komplexe besteht in der Koordination des Zinkatoms durch einen Cp*-Liganden sowie durch Neutralliganden. Die hohe Elektrophilie dieser Verbindungen ließ sich durch Reaktivitätsuntersuchungen belegen. Ein weiterer Ansatz zur Stabilisierung kationischer Zinkverbindungen besteht in der Verwendung funktionalisierter Cp-Liganden, die über eine neutrale Donorgruppe in einer Seitenkette verfügen. Es wurden neutrale und kationische Zinkkomplexe amino- sowie thiofunktionalisierter Cp-Liganden synthetisiert und charakterisiert. Für die kationischen Komplexe konnte eine intramolekulare Stabilisierung des Zinkatoms durch die Donorgruppe nachgewiesen werden. Einige der in dieser Arbeit beschriebenen Zinkkomplexe wurden als Präkatalysatoren intermolekularer Hydroaminierungsreaktionen eingesetzt, wobei teilweise hohe katalytische Aktivitäten erreicht wurden. Untersuchungen zum Mechanismus der Katalysereaktionen zeigten, dass eine hohe Elektrophilie des Zinkzentralatoms für eine effektive Katalyse entscheidend ist. / Cationic zinc complexes are assumed to act as catalytically active species in various Lewis acid catalyzed reactions. However, the mechanisms of these reactions are poorly understood. The aim of this dissertation is to synthesize structurally well-defined cationic zinc organyls as model compounds for catalytically active species in zinc catalyzed reactions. The thesis focuses on zinc complexes bearing cyclopentadienyl (Cp) ligands, as Cp ligands can stabilize unusual bonding situations. The successful synthesis and characterization of several cationic zinc complexes with pentamethylcyclopentadienyl (Cp*) ligands is described. As a common structural feature of these complexes, the zinc center is coordinated by a Cp* ligand and additional neutral ligands. The highly electrophilic character of these compounds was proven in reactivity studies. A further approach to stabilize cationic zinc compounds is to apply functionalized Cp ligands featuring a donor group in a side chain. Neutral and cationic zinc complexes bearing amino- and thio-functionalized Cp ligands were synthesized and characterized. The cationic donor-functionalized complexes were shown to exhibit an intramolecular stabilization of the zinc atoms by the donor groups. Several zinc complexes which are described in this thesis were examined as precatalysts in intermolecular hydroamination reactions. In some cases high catalytic activities were achieved. Studies on the mechanism of the catalysis reactions revealed that the presence of a highly electrophilic zinc center is crucial for good catalytic performance.

O objetivo deste trabalho foi investigar o uso de NbCl5 como ácido de Lewis em reações de cicloadição. Foram estudadas algumas reações de cicloadição [2 + 2], Reações de Diels-Alder entre enonas e ciclopentadieno e Reações da aza-Diels-Alder com bases de Schiff, avaliando o efeito da temperatura e da concentração molar do NbCl5. A comparação dos rendimentos, dos produtos formados e do tempo de reação com NbCl5, também foi um ponto fundamental da pesquisa. As reações de cicloadição [2 + 2] foram realizadas entre ésteres propiólicos e diferentes tipos de alcenos (éteres enólicos de silício e alcenos alifáticos). Nas reações com os éteres enólicos de silício não foi verificada a formação dos respectivos adutos de ciclobuteno, pois o NbCl5 promove a quebra da ligação oxigênio-silício, não levando à formação do produto desejado. Nas reações com os alcenos alifáticos foi possível obter o respectivo aduto, porém com rendimentos menores que com outros ácidos de Lewis. Quanto às reações de Diels-Alder, foram investigadas as reações entre diferentes ciclo-enonas (dienófilos de baixa reatividade) com ciclopentadieno (dieno) na presença de NbCl5. Os resultados obtidos indicam que o NbCl5 é um bom ácido de Lewis para ativar reações de Diels-Alder, apresentando tempos reacionais menores e alta diastereosseletividade a temperaturas mais baixas, quando comparado com outros ácidos de Lewis. A possibilidade de efetuar reações do Diels-Alder a -78 0C é um dos aspectos de destaque neste trabalho, pois, além de demonstrar a forte ativação do sistema enona exercido pelo NbCl5, possibilita obter produtos com alta seletividade. Paralelamente aos estudos de sistemática reacional foram realizados estudos de elucidação estrutural completa de alguns dos compostos sintetizados, utilizando-se diversas técnicas de RMN (uni e bidimensionais), e o auxílio de cálculos teóricos. Nas reações de aza-Diels-Alder entre bases de Schiff e di-hidropirano, o NbCl5 se mostrou um ótimo catalisador para a síntese de derivados de piranoquinolinas. Estes derivados formam uma importante classe de produtos naturais que apresentam ampla atividade biológica. As reações foram conduzidas com baixas concentrações de nióbio e em tempos relativamente curtos, obtendo-se rendimentos variando de 72 a 96 %. Outro fator a se destacar é a alta diastereosseletividade encontrada nestas reações. Também foram realizados estudos da atividade tripanocida dos derivados de piranoquinolinas preparados através das reações de aza-Diels-Alder catalisadas por NbCl5. / The aim of this work was to investigate the use of NbCl5 as Lewis acid in cycloadittion reactions. We have studied [2 + 2] cycloaddition reactions, Diels-Alder reactions between enonas and cyclopentadiene and aza-Diels-Alder reactions with Schiff bases. The effects of the temperature and of the molar concentration of NbCl5 were also evaluated. Comparasion of reaction yields, obtained products as well as reation time with NbCl5 were also a key point on this work. The [2 + 2] cycloaddition reactions were performed using propiolic ester and different types of alkenes (silyl enol ethers and aliphatic alkenes). In the reactions with silyl enol ethers, formation of the corresponding cyclobutene aductts was not verified, since the NbCl5 promotes the rupture of oxygen-silicon bonds, and the desired product is not obtained. In the reactions with aliphatic alkenes, it was possible to obtain the adduct, however, in lower yields as compared to those obtained with others Lewis acids. Regarding the Diels-Alder reactions, we have investigated reactions using different cycloenones (dienophiles of low reactivity) with cyclopentadiene (diene) with NbCl5. The obtained results indicate that NbCl5 is a good Lewis acid to activate these Diels-Alder reactions, resulting in shorter reaction times and higher diastereoselectivity at lower temperatures than other Lewis acids. The possibility of carrying out Diels-Alder reaction at -78 0C is another remarkable aspect of this work. Besides demonstrating the strong activation of the enone system by NbCl5, it opens the possibility of obtaining high stereoselectivity. We have also performed studies of complete structural elucidation of some compounds by using different NMR techniques (uni and bidimensional), with the help of theoretical calculations. In the aza-Diels-Alder reactions between Schiff bases and dihydropyran, the NbCl5 was an excellent catalyst for the synthesis of pyranoquinoline derivatives. These derivatives are an importante class of natural products that exhibit wide range of biological activity. The reactions were carried out at low concentration of niobium and in relatively short times, resulting in yields varying from 72 to 96 %. Another aspect that should be remarked is the high diastereoselectivity found in these reactions. We have also carried out studies of tripanocydal activity of pyranoquinoline derivatives prepared through aza-Diels-Alder reactions catalyzed by NbCl5.

INTRODUÇÃO: O câncer de pulmão é a principal causa de morte por câncer em todo o mundo e muitos pacientes apresentam derrame pleural em um estágio avançado da doença, com alta morbidade e mortalidade. Entretanto, a patogênese do derrame maligno é ainda pouco compreendida e as opções terapêuticas são limitadas. OBJETIVO: 1) Estudar a fisiopatologia do derrame pleural maligno em modelo animal com células de Lewis em diferentes concentrações; 2) Avaliar os efeitos da terapia intrapleural com anti-VEGF e anti-EGFR e a frequência de mutações de EGFR e KRAS neste modelo. MÉTODOS: Foi utilizado modelo de neoplasia pleural com camundongos C57BL/6 e células de Lewis (LLC) dividido em duas etapas: estudo com diferentes concentrações de células LLC (0,1, 0,5 e 1,5x105) e avaliação de terapias-alvo. Após a padronização do modelo, quatro grupos de camundongos receberam tratamento intrapleural com anti-VEGF, anti-EGFR, anti-VEGF+anti-EGFR ou solução fisiológica (não tratados) 3, 7, 10 e 14 dias após a indução da neoplasia pleural com 0,5x105 células LLC. Em vinte animais de cada grupo foi avaliada a curva de sobrevida. 160 animais foram submetidos à eutanásia 7, 10, 14 ou 21 dias após e avaliados peso, mobilidade, volume de líquido pleural, marcadores inflamatórios, imunológicos e bioquímicos no líquido, presença de tumores e alterações histológicas em pleura, pulmão, rim, fígado e baço. Através de imunohistoquimica avaliou-se apoptose, proliferação tumoral, VEGF e EGFR. Analisou-se a expressão gênica do EGFR, VEGF, KRAS e ALK e a frequência de mutações do EGFR e KRAS. Análise estatística: One Way ANOVA, Kaplan-Meier, p < 0,05. RESULTADOS: Na etapa de padronização do modelo observamos que a concentração que manteve os parâmetros de neoplasia pleural com maior sobrevida foi de 0,5x105 células LLC. Na segunda etapa do estudo, a carcinomatose pleural foi letal com sobrevida máxima de 25 dias, sem diferença entre os grupos. Redução de peso foi observada em todos os grupos após 21 dias. A mobilidade foi melhor nos grupos que receberam anti-EGFR. O volume de líquido pleural foi maior no grupo não tratado durante todo o estudo. Parâmetros imunológicos e bioquímicos aumentaram temporalmente sendo mais evidentes no grupo sem tratamento. Implantes tumorais na pleura foram mais evidentes no grupo não tratado após 14 dias. A inflamação pulmonar foi mínima em todos os grupos. No grupo não tratado observou-se implantes tumorais no pericárdio e músculo cardíaco após 21 dias, esteatose hepática e renal após 14 dias e hiperplasia de polpa branca do baço no 21º dia. Altos índices de apoptose e menores índices de proliferação tumoral foram observados nos grupos que receberam tratamento com anti-EGFR e anti-VEGF+anti-EGFR. Houve mutação do gene KRAS e superexpressão gênica tumoral do EGFR e do KRAS. CONCLUSÃO: As terapias-alvo reduziram significativamente o derrame pleural, morbidade e parâmetros histológicos, embora sem impacto na sobrevida dos animais neste modelo experimental. Nossos dados indicam que a linhagem tumoral LLC possui um fenótipo tumoral agressivo demonstrado através da mutação do KRAS e superexpressão do EGFR, o que pode estar associado ao pior prognóstico e menor resposta aos inibidores do EGFR / INTRODUCTION: Lung cancer is the leading cause of death by cancer in the world. Many patients have pleural effusion in an advanced stage of the disease, with high morbidity and mortality. However, the pathogenesis of malignant pleural effusion is still poorly understood and the treatment options are limited. OBJECTIVE: 1) To study the pathophysiology of malignant pleural effusion in animal model with Lewis cells in different concentrations; 2) Evaluate the effects of the intrapleural therapy with anti-VEGF and anti-EGFR and the frequency of EGFR and KRAS mutations in this model. METHODS: We used pleural neoplasm experimental model with mice C57BL/6 and Lewis cells (LLC) divided into two steps: study with different concentrations of LLC cells (0.1, 0.5 and 1.5x105) and evaluation of targeted therapies. After the standardization of the model, four groups of mice received intrapleural treatment with anti-VEGF, anti-EGFR, anti-VEGF+anti-EGFR or saline (untreated) 3, 7, 10 and 14 days after induction of pleural neoplasm with injection of 0.5x105 LLC cells. In 20 animals of each group was evaluated the survival curve. 160 animals underwent euthanasia 7, 10, 14 or 21 days after and assessed weight, mobility, volume of pleural fluid, inflammatory, immunological and biochemical markers in the liquid, presence of tumor and histological changes in pleura, lung, kidney, liver and spleen. It was evaluated, through immunohistochemistry, tumor apoptosis and proliferation, VEGF and EGFR. Gene expression of EGFR, VEGF, KRAS and ALK and frequency of mutations of EGFR and KRAS were also evaluated. Statistical analysis: One Way ANOVA, Kaplan-Meier, p < 0.05. RESULTS: In the standardization of the model we observed that the concentration that kept parameters of pleural neoplasm with higher survival rate was 0.5x105 LLC cells. In the second stage, target-therapies, pleural carcinomatosis was lethal with maximum survival of 25 days, with no difference between the groups. Weight decrease was observed in all groups after 21 days. Mobility was better in groups that receiving anti-EGFR. Pleural fluid volume was greater in the untreated group throughout the study. Immunological and biochemical parameters have increased temporarily being most evident in the untreated group. Tumor implants in pleura were more apparent in the untreated group after 14 days. The lung inflammation was minimal in all groups. The untreated group showed tumor implants in the pericardium and heart muscle after 21 days, hepatic and renal steatosis after 14 days and spleen white pulp hyperplasia in 21 day. High rates of apoptosis and smaller tumor proliferation indices were observed in groups that received treatment with anti-VEGF and anti-EGFR+anti-EGFR. We also found gene KRAS mutation and tumoral gene overexpression of EGFR and KRAS. CONCLUSION: Targeted therapies reduced significantly the pleural effusion, morbidity and histological parameters, although without an impact on survival rate in this experimental model. Our data indicate that the tumor lineage LLC has an aggressive tumor phenotype shown by KRAS mutation and overexpression of EGFR, which can be associated with a worse prognosis and a lower response to EGFR inhibitors

Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2018-02-07T18:29:25Z No. of bitstreams: 1 ulissescamargo_tese.pdf: 700757 bytes, checksum: 68231dab9197a8717320c0e887f2b2f6 (MD5) / Made available in DSpace on 2018-02-07T18:29:25Z (GMT). No. of bitstreams: 1 ulissescamargo_tese.pdf: 700757 bytes, checksum: 68231dab9197a8717320c0e887f2b2f6 (MD5) Previous issue date: 2016-09-22 / Introduction. The spondyloarthritis encomprises a group of diseases strongly associated with HLA-B*27 gene. It has been proposed that genes not belonging to the major histocompatibility complex human influence the genesis of these diseases especially in patients HLA-B*27 negative. Objectives. The aim of this study was to test the hypothesis that the antigens of the ABO, Secretor and Lewis histo-blood systems are associated with spondyloarthritis, especially ankylosing spondylitis (AS). Material and methods. Three hundred and ninety-four patients with clinical suspicion of spondyloarthritis sent for identification of HLA-B*27 gene were analyzed. One hundred and nineteen (30.2%) had confirmed the diagnosis of spondyloarthritis according to the ASAS criteria. The remaining 275 (69.8%) were used as controls. The identification of HLA-B*27 gene was performed using the PCR-SSOP method. The identification of the antigens of the ABO, Secretor and Lewis histo-blood systems was performed using hemagglutination and PCR-RFLP methods. The exact Fisher's test, the chi-square, and the values of Odds Ratio (OR) and Confidence Interval set at 95% were calculated using the GraphPad INSTAT software, accepting the error of 5%. Results. No statistically significant differences were observed in the frequency of antigenic profiles of ABO (χ2: 1.152; p = 0.764; GL: 3), Secreto (χ2: 0.779; p = 0.377; GL: 1) and Lewis (χ2: 1.853; p = 0.396; GL: 2) histo-blood groups between patients and controls. The Lea antigen was more frequent in patients with AS compared to controls (OR: 1.833; 95% CI: 1025- 3284, p = 0.053). This antigen was strongly associated with AS in HLA-B*27 negative patients compared to controls (OR: 4.469; 95% CI: 1931-10342; p = 0.0007). This association remained only in males in the absence of HLA-B*27 gene (OR: 6.880; 95% CI: 1852-25564; p = 0.004). Conclusions. AS is associated to the Lea antigen in HLAB* 27 negative male patients. / Introdução. As espondiloartrites compreendem um grupo de doenças fortemente associadas ao gene HLA-B*27. Tem sido proposto que genes não pertencentes ao complexo principal de histocompatibilidade humano influenciam a gênese destas doenças especialmente nos pacientes HLA-B*27 negativos. Objetivos. O objetivo deste estudo foi testar a hipótese de que os antígenos dos sistemas histo-sanguíneos ABO, Secretor e Lewis estão associados à espondiloartrites, especialmente a espondilite anquilosante (EA). Material e método. Foram analisados 394 pacientes com suspeita clínica de espondiloartrites encaminhados para identificação do gene HLA-B*27. Cento e dezenove (30,2%) tiveram o diagnóstico de espondiloartrite confirmado de acordo com os critérios ASAS. Os 275 (69,8%) restantes compuseram o grupo controle. A identificação do gene HLA-B*27 foi realizada com o uso do método PCR-SSOP. A caracterização dos antígenos dos sistemas histo-sanguíneos ABO, Secretor e Lewis foi realizada com o uso dos métodos hemaglutinação e PCR-RFLP. O teste exato de Fisher, o qui-quadrado, os valores de Odds Ratio (OR) e do intervalo de confiança a 95% foram calculados com o uso do software GraphPad Instat, aceitando o erro de 5%. Resultados. Não foram observadas diferenças estatisticamente significantes nas frequências dos perfis antigênicos dos sistemas histo-sanguíneos ABO (χ2: 1.152; p=0,764; GL: 3), Secretor (χ2: 0.779; p=0,377; GL: 1) e Lewis (χ2: 1.853; p=0,396; GL: 2) de pacientes e controles. Foi observada maior frequência do antígeno Lea em pacientes com EA, comparados aos controles (OR: 1.833; IC 95%: 1.025 – 3.284; p=0,053). Este antígeno mostrou-se fortemente associado à EA em pacientes HLA-B*27 negativos comparados aos controles (OR: 4.469; IC 95%: 1.931 – 10.342; p=0,0007). Esta associação se manteve apenas no gênero masculino na ausência do gene HLA-B*27 (OR: 6.880; IC 95%: 1.852 – 25.564; p = 0,004). Conclusões. A EA está associada ao antígeno Lea nos pacientes masculinos HLA-B*27 negativos.

Made available in DSpace on 2014-12-17T15:42:00Z (GMT). No. of bitstreams: 1 JulioCOS_DISSERT.pdf: 1559177 bytes, checksum: 5d76456c4b64130c51ab0adec9c84e15 (MD5) Previous issue date: 2010-08-16 / This research aims at identifying the learning problems in newly undergraduate students at university, interpreting the nature and causes of these problems, offering subsidies to overcome these difficulties and enabling a meaningful learning through which students give meaning to their learning. As an object for this work was chosen the theme Chemical Bonds - where were studied the forces between atoms to form molecules, compound ions and ionic crystalline structures - and is characterized as one of the most important subjects of Chemistry. In research, it was used a questionnaire with five open questions, answered by 147 students from the early periods of degrees in Chemistry at Universidade Federal do f Rio Grande do Norte. The answers revealed uncertainty on the part of students, both conceptual and representation, with superficial justifications, always using the octet rule to describe models of chemical bonds. Results suggest that these students had inadequate training in high school and that the examinations for entrance into the ranks were made according to flexible criteria less demanding in terms of knowledge. These observations have led to the conclusion that for future changes, it is necessary for high schools and in the early periods in universities favoring the adoption of pedagogical approaches in context and applying strategies to overcome the teaching of superficial memorization on Chemical Bonds, which probably have applied to the teaching of other subjects of chemistry / Este trabalho teve o objetivo de identificar problemas de aprendizagem em alunos de gradua??o rec?m ingressante na universidade, interpretar a natureza e as causas desses problemas, oferecendo subs?dios para supera??o de tais dificuldades e possibilitando uma aprendizagem significava atrav?s da qual o aluno atribua sentido em seu aprendizado. Para o desenvolvimento desse trabalho foi escolhido o tema Liga??es Qu?micas - onde se estudam as for?as que agem entre os ?tomos para formar mol?culas, ?ons compostos ou estruturas cristalinas i?nicas -, que se caracteriza como um dos mais importantes assuntos da Qu?mica. Para isso, utilizou-se um question?rio com cinco perguntas abertas, respondidas por 147 estudantes dos per?odos iniciais das gradua??es em Qu?mica da Universidade Federal do Rio Grande do Norte. As respostas obtidas revelaram inseguran?a dos estudantes, tanto em termos conceituais quanto de representa??o, com justificativas superficiais, recorrendo sempre ? regra do octeto para descrever modelos de liga??es qu?micas. Os resultados sugerem que esses estudantes tiveram uma forma??o inadequada, no ensino m?dio e que os exames para ingresso nas gradua??es se fizeram segundo crit?rios pouco exigentes em termos de conhecimentos. As observa??es feitas levam ? conclus?o de que, para mudan?as futuras, ? necess?rio que escolas de ensino m?dio e dos per?odos iniciais nas universidades privilegiem a ado??o de m?todos pedag?gicos contextualizados, aplicando estrat?gias para superar o ensino memor?stico e superficial sobre Liga??es Qu?micas, o que, provavelmente, se aplica ao ensino de outros temas da Qu?mica

INTRODUÇÃO: O câncer de pulmão é a principal causa de morte por câncer em todo o mundo e muitos pacientes apresentam derrame pleural em um estágio avançado da doença, com alta morbidade e mortalidade. Entretanto, a patogênese do derrame maligno é ainda pouco compreendida e as opções terapêuticas são limitadas. OBJETIVO: 1) Estudar a fisiopatologia do derrame pleural maligno em modelo animal com células de Lewis em diferentes concentrações; 2) Avaliar os efeitos da terapia intrapleural com anti-VEGF e anti-EGFR e a frequência de mutações de EGFR e KRAS neste modelo. MÉTODOS: Foi utilizado modelo de neoplasia pleural com camundongos C57BL/6 e células de Lewis (LLC) dividido em duas etapas: estudo com diferentes concentrações de células LLC (0,1, 0,5 e 1,5x105) e avaliação de terapias-alvo. Após a padronização do modelo, quatro grupos de camundongos receberam tratamento intrapleural com anti-VEGF, anti-EGFR, anti-VEGF+anti-EGFR ou solução fisiológica (não tratados) 3, 7, 10 e 14 dias após a indução da neoplasia pleural com 0,5x105 células LLC. Em vinte animais de cada grupo foi avaliada a curva de sobrevida. 160 animais foram submetidos à eutanásia 7, 10, 14 ou 21 dias após e avaliados peso, mobilidade, volume de líquido pleural, marcadores inflamatórios, imunológicos e bioquímicos no líquido, presença de tumores e alterações histológicas em pleura, pulmão, rim, fígado e baço. Através de imunohistoquimica avaliou-se apoptose, proliferação tumoral, VEGF e EGFR. Analisou-se a expressão gênica do EGFR, VEGF, KRAS e ALK e a frequência de mutações do EGFR e KRAS. Análise estatística: One Way ANOVA, Kaplan-Meier, p < 0,05. RESULTADOS: Na etapa de padronização do modelo observamos que a concentração que manteve os parâmetros de neoplasia pleural com maior sobrevida foi de 0,5x105 células LLC. Na segunda etapa do estudo, a carcinomatose pleural foi letal com sobrevida máxima de 25 dias, sem diferença entre os grupos. Redução de peso foi observada em todos os grupos após 21 dias. A mobilidade foi melhor nos grupos que receberam anti-EGFR. O volume de líquido pleural foi maior no grupo não tratado durante todo o estudo. Parâmetros imunológicos e bioquímicos aumentaram temporalmente sendo mais evidentes no grupo sem tratamento. Implantes tumorais na pleura foram mais evidentes no grupo não tratado após 14 dias. A inflamação pulmonar foi mínima em todos os grupos. No grupo não tratado observou-se implantes tumorais no pericárdio e músculo cardíaco após 21 dias, esteatose hepática e renal após 14 dias e hiperplasia de polpa branca do baço no 21º dia. Altos índices de apoptose e menores índices de proliferação tumoral foram observados nos grupos que receberam tratamento com anti-EGFR e anti-VEGF+anti-EGFR. Houve mutação do gene KRAS e superexpressão gênica tumoral do EGFR e do KRAS. CONCLUSÃO: As terapias-alvo reduziram significativamente o derrame pleural, morbidade e parâmetros histológicos, embora sem impacto na sobrevida dos animais neste modelo experimental. Nossos dados indicam que a linhagem tumoral LLC possui um fenótipo tumoral agressivo demonstrado através da mutação do KRAS e superexpressão do EGFR, o que pode estar associado ao pior prognóstico e menor resposta aos inibidores do EGFR / INTRODUCTION: Lung cancer is the leading cause of death by cancer in the world. Many patients have pleural effusion in an advanced stage of the disease, with high morbidity and mortality. However, the pathogenesis of malignant pleural effusion is still poorly understood and the treatment options are limited. OBJECTIVE: 1) To study the pathophysiology of malignant pleural effusion in animal model with Lewis cells in different concentrations; 2) Evaluate the effects of the intrapleural therapy with anti-VEGF and anti-EGFR and the frequency of EGFR and KRAS mutations in this model. METHODS: We used pleural neoplasm experimental model with mice C57BL/6 and Lewis cells (LLC) divided into two steps: study with different concentrations of LLC cells (0.1, 0.5 and 1.5x105) and evaluation of targeted therapies. After the standardization of the model, four groups of mice received intrapleural treatment with anti-VEGF, anti-EGFR, anti-VEGF+anti-EGFR or saline (untreated) 3, 7, 10 and 14 days after induction of pleural neoplasm with injection of 0.5x105 LLC cells. In 20 animals of each group was evaluated the survival curve. 160 animals underwent euthanasia 7, 10, 14 or 21 days after and assessed weight, mobility, volume of pleural fluid, inflammatory, immunological and biochemical markers in the liquid, presence of tumor and histological changes in pleura, lung, kidney, liver and spleen. It was evaluated, through immunohistochemistry, tumor apoptosis and proliferation, VEGF and EGFR. Gene expression of EGFR, VEGF, KRAS and ALK and frequency of mutations of EGFR and KRAS were also evaluated. Statistical analysis: One Way ANOVA, Kaplan-Meier, p < 0.05. RESULTS: In the standardization of the model we observed that the concentration that kept parameters of pleural neoplasm with higher survival rate was 0.5x105 LLC cells. In the second stage, target-therapies, pleural carcinomatosis was lethal with maximum survival of 25 days, with no difference between the groups. Weight decrease was observed in all groups after 21 days. Mobility was better in groups that receiving anti-EGFR. Pleural fluid volume was greater in the untreated group throughout the study. Immunological and biochemical parameters have increased temporarily being most evident in the untreated group. Tumor implants in pleura were more apparent in the untreated group after 14 days. The lung inflammation was minimal in all groups. The untreated group showed tumor implants in the pericardium and heart muscle after 21 days, hepatic and renal steatosis after 14 days and spleen white pulp hyperplasia in 21 day. High rates of apoptosis and smaller tumor proliferation indices were observed in groups that received treatment with anti-VEGF and anti-EGFR+anti-EGFR. We also found gene KRAS mutation and tumoral gene overexpression of EGFR and KRAS. CONCLUSION: Targeted therapies reduced significantly the pleural effusion, morbidity and histological parameters, although without an impact on survival rate in this experimental model. Our data indicate that the tumor lineage LLC has an aggressive tumor phenotype shown by KRAS mutation and overexpression of EGFR, which can be associated with a worse prognosis and a lower response to EGFR inhibitors

Ces travaux de thèse portent sur l’élaboration et l’étude des propriétés thermomécaniques de polymères dynamiques incorporant des dérivés borés. Tout en appliquant ce concept sur une variété d’architectures macromoléculaires : copolymères fonctionnels, briques di- et tri-fonctionelles, deux réactivités distinctes du bore ont été étudiées et exploitées. Une large gamme de méthodes de caractérisation a été utilisée pour mener à bien ce projet : spectroscopies FTIR et RMN sous différents stimuli, ainsi que de nombreuses analyses thermiques et mécaniques. Dans un premier temps, nous avons considéré la formation de paires de Lewis frustrées entre des acides de Lewis (organoboranes) et des bases de Lewis (amines et phosphines) stériquement encombrés, cette interaction pouvant être fortement modulée par la participation d’un troisième composé tels que des molécules de gaz. Ainsi, nous avons été capables de former des réseaux dynamiques réticulables de façon réversible avec le dioxyde de carbone. Dans un second temps, nous avons mis en évidence une nouvelle réactivité dans les esters boroniques cycliques impliquant une ouverture de cycle à haute température, assistée par la présence de nucléophiles. Cette réaction a été mise à profit pour former des polymères réticulés dynamiquement, pouvant atteindre des températures de transition vitreuse jusqu’à 220°C et dé-réticulables par dilution avec un bon solvant du polymère (apolaire). Cette réactivité a été appliquée à une variété de polymères accessibles par copolymérisation radicalaire (styrène, éthylène, acétate de vinyle, acrylate de butyle) ou par post-fonctionnalisation de polymères commerciaux (polybutadiène) / This thesis focuses on the development and study of thermomechanical properties of dynamic polymers incorporating borylated derivatives. While applying this concept to a variety of macromolecular architectures: functional copolymers, di- and tri-functional bricks, two distinct reactivities of boron have been explored. A wide range of characterization methods has been used to carry out this project: FTIR and NMR spectroscopies under numerous stimuli, as well as many thermal and mechanical analyses. In a first step, we considered the formation of Frustrated Lewis Pairs between Lewis acids (organoboranes) and Lewis bases (amines and phosphines) sterically hindered, as this interaction can be strongly modulated by the participation of a third compound such as gas molecules. Thus, we have been able to form dynamic networks reversibly crosslinkable with carbon dioxide. In a second step, we demonstrated a new reactivity in cyclic boronic esters involving a ring-opening at high temperature, assisted by the presence of nucleophiles. This reaction has been used to form dynamically crosslinked polymers, which can reach glass transition temperatures up to 220°C and de-crosslinkable by dilution in a good (apolar) polymer solvent. This reactivity has been applied to a variety of polymers accessible by radical copolymerization (styrene, ethylene, vinyl acetate, butyl acrylate) or by post-functionalization of commercial polymers (polybutadiene)

Die feste nichtkristalline Lewis-Säure Aluminiumchlorofluorid (ACF, AlCl(x)F(3-x), x = 0.05 .. 0.3) hat die höchste bisher bekannte Lewis-Acidität aller heterogenen Katalysatoren. Sie erreicht die Stärke von Antimonpentafluorid SbF5 und übertrifft sie in manchen Fällen sogar. In dieser Arbeit wurden die Bulk-Struktur des ACF und der sehr ähnlichen Verbindung Aluminiumbromofluorid (ABF) mittels IR-, ESR-, NMR- und Röntgenabsorptionsspektroskopie studiert. Die Oberfläche der Verbindungen wurde durch die Adsorption von Gasen bei niedrigen Temperaturen untersucht, sowie durch IR- und ESR-Spektroskopie adsorbierter Sondenmoleküle. Das thermische Verhalten dieser nichtkristallinen Verbindungen wurde mittels DTA verfolgt. Die Lewis-Acidität kleiner Modellverbindungen wurde NMR-spektroskopisch und mit ab initio Methoden untersucht. Alle Daten wurden mit denen der gut charakterisierten und bekannten Modifikationen des Aluminiumfluorids (AlF3) verglichen. Die kombinierten Ergebnisse der Messungen an beiden festen Phasen erlauben die Entwicklung eines Strukturmodells für diese Verbindungen, das die meisten spektroskopischen Daten und die außergewöhnlich hohe Lewis-Acidität erklären kann. Beide Phasen sind sehr ähnlich zueinander. Das Vorhandensein des schwereren Halogens (Cl, Br) erzeugt eine Störung des Netzwerkes und verhindert die Ausbildung geordneter Strukturen. Der Grad der Unordnung in diesen Phasen ist höher als bei allen anderen Verbindungen des Aluminiumfluorids. Daraus resultiert eine gestörte Oberfläche, was wiederum zu koordinativ ungesättigtem Aluminium an der Oberfläche führt. Die sauren Zentren in ACF und ABF sind stärker als in anderen aluminiumhaltigen Lewis-Säuren. / The solid non-crystalline Lewis acid aluminum chlorofluoride (ACF, AlCl(x)F(3-x), x = 0.05 .. 0.3) has the highest Lewis acidity of any heterogeneous catalyst known so far. It reaches the acidity of antimony pentafluoride (SbF5) and in some cases even exceeds it. In this work the bulk structure of ACF and of the very similar compound aluminium bromofluoride (ABF) was studied by IR, ESR, NMR, and X-ray absorption spectroscopy. The surface of the compounds was investigated by adsorption of gases at low temperatures, as well as by IR and ESR spectroscopy of adsorbed probe molecules. The thermal behavior of these non-crystalline compounds was followed by DTA. The Lewis acidity of small model compounds was studied by NMR spectroscopy and ab initio calculations. All data were compared to those of well characterized known samples of the different modifications of aluminum fluoride (AlF3). The combined results of the measurements of both solid phases allow to set up a structure model for these compounds which can explain most of the spectrocopic data and the extraordinary high Lewis acidity. Both phases are very similar to each other. The occurrence of the heavier halogen (Cl, Br) causes a perturbation of the network and prevents it from forming ordered structures. The degree of disorder of these phases is higher than for any other known compounds of aluminum fluoride. This results in an disordered surface which leads to coordinatively unsaturated aluminum at the surface. The acidic centers of ACF and ABF are stronger than in any other aluminum containing Lewis acid.