Sabe-se que o flúor causa alterações químicas e celulares no osso, dependendo da dosagem e do tempo de exposição a esse elemento. Já foi demonstrado que alterações clínicas importantes, como a osteoporose, osteopetrose e esclerose óssea, podem ser geradas pela ingestão de flúor. Sabe-se que o flúor pode guiar os osteoblastos ao crescimento, sob doses e tempos de exposição específicos. A sensibilidade dos tecidos mineralizados ao fluoreto responde a mecanismos genéticos inerentes a cada população. Dentro de uma mesma espécie, diferentes linhagens apresentam um comportamento distinto frente a esse fármaco. Durante várias décadas, os estudos com fluoretos resumiram-se ao fluoreto de sódio, amplamente utilizado na prevenção das cáries dentárias. Recentemente, outras fontes de fluoretos como TiF4 e SnF2 têm sido buscadas, com intuito de potencializar as vantagens desse elemento. Porém não existem estudos ainda sobre o efeito do AlF3 sobre o tecido ósseo até a presente data. Desse modo, achamos oportuno investigar seu papel, quando administrado a células ósseas e para tal, investigamos a viabilidade e padrão de atividade das fosfatases desse sal (AlF3) quando administrado às células da linhagem pré-osteblástica MC3T3, em comparação ao NaF. Além disso, sabendo que diferentes células apresentam comportamento distinto ao tratamento com fluoretos, estudamos o papel do NaF quando administrado a duas linhagens celulares de camundongos com densidades ósseas distintas e com diferentes susceptibilidades ao fluoreto: C3H/HeJ e C57BL/6J (C3H e C57, alta e baixa densidades ósseas, respectivamente). As células também foram avaliadas quanto à viabilidade celular e ao perfil das fosfatases. Todos os resultados foram submetidos à Análise de Variância a três critérios e nos permitiu identificar que entre os sais de fluoreto, apenas o NaF promoveu alterações na viabilidade celular das células MC3T3. O AlF3 não exerceu influência na atividade da fosfatase alcalina quando consideramos as células pré-osteoblásticas, no entanto, o efeito desse fluoreto sobre a atividade das fosfatases ácidas totais e ácida resistente ao tartarato ocorre de modo dicotômico. Quando consideramos uma população celular heterogênea, coletada de calvária, como foi o caso das linhagens C3H e C57, verificamos que o NaF interferiu tanto sobre a proliferação, quanto a atividade das fosfatases de modo bastante distinto para ambas linhagens celulares. Assim concluimos que o NaF é capaz de exercer efeitos mais diversificados em diferentes tipos celulares, alterando viabilidade celular e atividade de enzimas; em contrapartida, o AlF3 produz efeitos mais especifícos e delimitados em pré-osteoblastos. / It is well known that fluoride causes chemical and cellular alteration on bone tissue, depending on the dosage and time of exposure to this element. Several studies have been conducted to show that some bone diseases, such as osteoporosis, osteopetrosis and esclerosis, can occur as a consequence of the excessive fluoride uptake. Fluoride can lead osteoblast to proliferate, under certain conditions as time and dosage. The same way, excessive dosages of fluoride can alter protein activity in osteoblasts, by changing the expression of retated genes. Sensitivity of mineralized tissues to fluoride depends on a genetic background inherent to each population. Within the same specie, different lineages present distint behavior to the ingestion of this íon. Over several decades, many researches focused on the study of NaF as the only source of fluoride, once it is wide spread used to the prevention of dental caries. More recently, different sources of fluoride have been assessed, like TiF4 e SnF2</sub, with the main aim to enhance biochemical and physical benefits of this element. Despite of this, none of these formulations have been tested to evaluate their effect on the bone tissue. Thus, we believe it is advisable to investigate viability and phosphatases activities of pre-osteoblast MC3T3 cells treated with Aluminium fluoride, compared to NaF treatments. Besides this, facing the knowledge that different cell lines have distinct behavior when treated with fluoride, we used two inbred strains of mice with distint mineral bone densities, C3H/HeJ (C3H, high bone density) and C57BL/6J (C57, low bone density), to assess the viability and phosphatases activities after the treatment with NaF. Overall results were tested by 3 way- Anova. AlF3 did not exibit influence over on alkaline phosphatase when pre-osteoblast cells are considered, but the effect of this fluoride salt on the activity of total and tartarate resistant acid phosphatases ocurrs on a dicotomic way. When we consider a mixed cell population, collected from calvária as for the C3H and C57 assays, NaF did interfered as with the proliferation rate as phosphatase activities on a very distinct fashion between the two lineages. Thus, it is possible to conclude that NaF is able to exert variable effects in different cell types and enzyme activities; on the other hand, AlF3 effects are more specific and surrounded in pre-osteblastic cells.

Sabe-se que o flúor causa alterações químicas e celulares no osso, dependendo da dosagem e do tempo de exposição a esse elemento. Já foi demonstrado que alterações clínicas importantes, como a osteoporose, osteopetrose e esclerose óssea, podem ser geradas pela ingestão de flúor. Sabe-se que o flúor pode guiar os osteoblastos ao crescimento, sob doses e tempos de exposição específicos. A sensibilidade dos tecidos mineralizados ao fluoreto responde a mecanismos genéticos inerentes a cada população. Dentro de uma mesma espécie, diferentes linhagens apresentam um comportamento distinto frente a esse fármaco. Durante várias décadas, os estudos com fluoretos resumiram-se ao fluoreto de sódio, amplamente utilizado na prevenção das cáries dentárias. Recentemente, outras fontes de fluoretos como TiF4 e SnF2 têm sido buscadas, com intuito de potencializar as vantagens desse elemento. Porém não existem estudos ainda sobre o efeito do AlF3 sobre o tecido ósseo até a presente data. Desse modo, achamos oportuno investigar seu papel, quando administrado a células ósseas e para tal, investigamos a viabilidade e padrão de atividade das fosfatases desse sal (AlF3) quando administrado às células da linhagem pré-osteblástica MC3T3, em comparação ao NaF. Além disso, sabendo que diferentes células apresentam comportamento distinto ao tratamento com fluoretos, estudamos o papel do NaF quando administrado a duas linhagens celulares de camundongos com densidades ósseas distintas e com diferentes susceptibilidades ao fluoreto: C3H/HeJ e C57BL/6J (C3H e C57, alta e baixa densidades ósseas, respectivamente). As células também foram avaliadas quanto à viabilidade celular e ao perfil das fosfatases. Todos os resultados foram submetidos à Análise de Variância a três critérios e nos permitiu identificar que entre os sais de fluoreto, apenas o NaF promoveu alterações na viabilidade celular das células MC3T3. O AlF3 não exerceu influência na atividade da fosfatase alcalina quando consideramos as células pré-osteoblásticas, no entanto, o efeito desse fluoreto sobre a atividade das fosfatases ácidas totais e ácida resistente ao tartarato ocorre de modo dicotômico. Quando consideramos uma população celular heterogênea, coletada de calvária, como foi o caso das linhagens C3H e C57, verificamos que o NaF interferiu tanto sobre a proliferação, quanto a atividade das fosfatases de modo bastante distinto para ambas linhagens celulares. Assim concluimos que o NaF é capaz de exercer efeitos mais diversificados em diferentes tipos celulares, alterando viabilidade celular e atividade de enzimas; em contrapartida, o AlF3 produz efeitos mais especifícos e delimitados em pré-osteoblastos. / It is well known that fluoride causes chemical and cellular alteration on bone tissue, depending on the dosage and time of exposure to this element. Several studies have been conducted to show that some bone diseases, such as osteoporosis, osteopetrosis and esclerosis, can occur as a consequence of the excessive fluoride uptake. Fluoride can lead osteoblast to proliferate, under certain conditions as time and dosage. The same way, excessive dosages of fluoride can alter protein activity in osteoblasts, by changing the expression of retated genes. Sensitivity of mineralized tissues to fluoride depends on a genetic background inherent to each population. Within the same specie, different lineages present distint behavior to the ingestion of this íon. Over several decades, many researches focused on the study of NaF as the only source of fluoride, once it is wide spread used to the prevention of dental caries. More recently, different sources of fluoride have been assessed, like TiF4 e SnF2</sub, with the main aim to enhance biochemical and physical benefits of this element. Despite of this, none of these formulations have been tested to evaluate their effect on the bone tissue. Thus, we believe it is advisable to investigate viability and phosphatases activities of pre-osteoblast MC3T3 cells treated with Aluminium fluoride, compared to NaF treatments. Besides this, facing the knowledge that different cell lines have distinct behavior when treated with fluoride, we used two inbred strains of mice with distint mineral bone densities, C3H/HeJ (C3H, high bone density) and C57BL/6J (C57, low bone density), to assess the viability and phosphatases activities after the treatment with NaF. Overall results were tested by 3 way- Anova. AlF3 did not exibit influence over on alkaline phosphatase when pre-osteoblast cells are considered, but the effect of this fluoride salt on the activity of total and tartarate resistant acid phosphatases ocurrs on a dicotomic way. When we consider a mixed cell population, collected from calvária as for the C3H and C57 assays, NaF did interfered as with the proliferation rate as phosphatase activities on a very distinct fashion between the two lineages. Thus, it is possible to conclude that NaF is able to exert variable effects in different cell types and enzyme activities; on the other hand, AlF3 effects are more specific and surrounded in pre-osteblastic cells.

Sonic hedgehog (Shh) is a secreted morphogen involved in patterning a wide range of structures in the developing embryo. When cells receive the Shh signal a cascade of effects begin which in turn regulate downstream target genes. The genes controlled by Sonic hedgehog provide messages instructing cells how to differentiate or when to divide. Disruption of the hedgehog signalling cascade leads to a number of developmental disorders and plays a key role in the formation of a range of human cancers. Patched, the receptor for Shh, acts as a tumour suppressor and is mutated in naevoid basal cell carcinoma syndrome (NBCCS). NBCCS patients display a susceptibility to tumour formation, particularly for basal cell carcinoma (BCC). The discovery of Patched mutations in sporadic BCCs and other tumour types further highlights the importance of this pathway to human cancer. The identification of genes regulated by hedgehog is crucial for understanding how disruption of this pathway leads to neoplastic transformation. It is assumed that the abnormal expression of such genes plays a large role in directing cells to divide at inappropriate times. Only a small number of genes controlled by Shh have been described in vertebrate tissues. In the work presented in this thesis a Sonic hedgehog responsive embryonic mouse cell line, C3H/10T1/2, was used as a model system for hedgehog target gene discovery. Known downstream target genes were profiled to determine their induction kinetics, building up a body of knowledge on the response to Shh for this cell type. During this work, it was discovered that C3H/10T1/2 cells do not become fully competent to respond to Shh stimulation until the cells reach a critical density, a factor that had to be taken into account when determining timepoints of interest for further investigation. Several techniques were employed to identify genes that show expression changes between Shh stimulated and control cells. In one of these techniques, RNA from cell cultures activated with Shh was used to interrogate cDNA microarrays, and this provided many insights into the downstream transcriptional consequences of hedgehog stimulation. Microarrays consist of thousands of spots of DNA of known sequence gridded onto glass slides. Experiments using this technology allow the expression level of thousands of genes to be measured simultaneously. Independent stimulation methods combined with northern blotting were used to investigate individual genes of interest, allowing genuine targets to be confirmed and false positives eliminated. This resulted in the identification of eleven target genes. Seven of these are induced by Sonic hedgehog (Thrombomodulin (Thbd), Glucocorticoid induced leucine zipper (Gilz), Brain factor 2 (Bf2), Nuclear receptor subfamily 4, group A, member 1 (Nr4a1), Insulin-like growth factor 2 (Igf2), Peripheral myelin protein 22 (Pmp22), Lim and SH3 Protein 1 (Lasp1)), and four are repressed (Secreted frizzled related proteins 1 and 2 (Sfrp1 and Sfrp2), Macrophage inflammatory protein-1 gamma (Mip-1?), and Anti-mullerian hormone (Amh)). The majority of these represent novel downstream genes not previously reported as targets of Shh. The new target genes have a diverse range of functions, and include transcriptional regulators and molecules known to be involved in regulating cell growth or apoptosis. The corroboration of genes previously implicated in hedgehog signalling, along with the finding of novel targets, demonstrates both the validity and power of the C3H/10T1/2 system for Shh target gene discovery. The identification of novel Sonic hedgehog responsive genes provides candidates whose abnormal expression may be decisive in initiating tumour formation and future studies will investigate their role in development and disease. It is expected that such findings will provide vital clues to the aetiology of various human cancers, and that an understanding of their roles may ultimately provide greater opportunities in the future design of anti-tumour therapies.

Sonic hedgehog (Shh) is a secreted morphogen involved in patterning a wide range of structures in the developing embryo. When cells receive the Shh signal a cascade of effects begin which in turn regulate downstream target genes. The genes controlled by Sonic hedgehog provide messages instructing cells how to differentiate or when to divide. Disruption of the hedgehog signalling cascade leads to a number of developmental disorders and plays a key role in the formation of a range of human cancers. Patched, the receptor for Shh, acts as a tumour suppressor and is mutated in naevoid basal cell carcinoma syndrome (NBCCS). NBCCS patients display a susceptibility to tumour formation, particularly for basal cell carcinoma (BCC). The discovery of Patched mutations in sporadic BCCs and other tumour types further highlights the importance of this pathway to human cancer. The identification of genes regulated by hedgehog is crucial for understanding how disruption of this pathway leads to neoplastic transformation. It is assumed that the abnormal expression of such genes plays a large role in directing cells to divide at inappropriate times. Only a small number of genes controlled by Shh have been described in vertebrate tissues. In the work presented in this thesis a Sonic hedgehog responsive embryonic mouse cell line, C3H/10T1/2, was used as a model system for hedgehog target gene discovery. Known downstream target genes were profiled to determine their induction kinetics, building up a body of knowledge on the response to Shh for this cell type. During this work, it was discovered that C3H/10T1/2 cells do not become fully competent to respond to Shh stimulation until the cells reach a critical density, a factor that had to be taken into account when determining timepoints of interest for further investigation. Several techniques were employed to identify genes that show expression changes between Shh stimulated and control cells. In one of these techniques, RNA from cell cultures activated with Shh was used to interrogate cDNA microarrays, and this provided many insights into the downstream transcriptional consequences of hedgehog stimulation. Microarrays consist of thousands of spots of DNA of known sequence gridded onto glass slides. Experiments using this technology allow the expression level of thousands of genes to be measured simultaneously. Independent stimulation methods combined with northern blotting were used to investigate individual genes of interest, allowing genuine targets to be confirmed and false positives eliminated. This resulted in the identification of eleven target genes. Seven of these are induced by Sonic hedgehog (Thrombomodulin (Thbd), Glucocorticoid induced leucine zipper (Gilz), Brain factor 2 (Bf2), Nuclear receptor subfamily 4, group A, member 1 (Nr4a1), Insulin-like growth factor 2 (Igf2), Peripheral myelin protein 22 (Pmp22), Lim and SH3 Protein 1 (Lasp1)), and four are repressed (Secreted frizzled related proteins 1 and 2 (Sfrp1 and Sfrp2), Macrophage inflammatory protein-1 gamma (Mip-1?), and Anti-mullerian hormone (Amh)). The majority of these represent novel downstream genes not previously reported as targets of Shh. The new target genes have a diverse range of functions, and include transcriptional regulators and molecules known to be involved in regulating cell growth or apoptosis. The corroboration of genes previously implicated in hedgehog signalling, along with the finding of novel targets, demonstrates both the validity and power of the C3H/10T1/2 system for Shh target gene discovery. The identification of novel Sonic hedgehog responsive genes provides candidates whose abnormal expression may be decisive in initiating tumour formation and future studies will investigate their role in development and disease. It is expected that such findings will provide vital clues to the aetiology of various human cancers, and that an understanding of their roles may ultimately provide greater opportunities in the future design of anti-tumour therapies.

Sonic hedgehog (Shh) is a secreted morphogen involved in patterning a wide range of structures in the developing embryo. When cells receive the Shh signal a cascade of effects begin which in turn regulate downstream target genes. The genes controlled by Sonic hedgehog provide messages instructing cells how to differentiate or when to divide. Disruption of the hedgehog signalling cascade leads to a number of developmental disorders and plays a key role in the formation of a range of human cancers. Patched, the receptor for Shh, acts as a tumour suppressor and is mutated in naevoid basal cell carcinoma syndrome (NBCCS). NBCCS patients display a susceptibility to tumour formation, particularly for basal cell carcinoma (BCC). The discovery of Patched mutations in sporadic BCCs and other tumour types further highlights the importance of this pathway to human cancer. The identification of genes regulated by hedgehog is crucial for understanding how disruption of this pathway leads to neoplastic transformation. It is assumed that the abnormal expression of such genes plays a large role in directing cells to divide at inappropriate times. Only a small number of genes controlled by Shh have been described in vertebrate tissues. In the work presented in this thesis a Sonic hedgehog responsive embryonic mouse cell line, C3H/10T1/2, was used as a model system for hedgehog target gene discovery. Known downstream target genes were profiled to determine their induction kinetics, building up a body of knowledge on the response to Shh for this cell type. During this work, it was discovered that C3H/10T1/2 cells do not become fully competent to respond to Shh stimulation until the cells reach a critical density, a factor that had to be taken into account when determining timepoints of interest for further investigation. Several techniques were employed to identify genes that show expression changes between Shh stimulated and control cells. In one of these techniques, RNA from cell cultures activated with Shh was used to interrogate cDNA microarrays, and this provided many insights into the downstream transcriptional consequences of hedgehog stimulation. Microarrays consist of thousands of spots of DNA of known sequence gridded onto glass slides. Experiments using this technology allow the expression level of thousands of genes to be measured simultaneously. Independent stimulation methods combined with northern blotting were used to investigate individual genes of interest, allowing genuine targets to be confirmed and false positives eliminated. This resulted in the identification of eleven target genes. Seven of these are induced by Sonic hedgehog (Thrombomodulin (Thbd), Glucocorticoid induced leucine zipper (Gilz), Brain factor 2 (Bf2), Nuclear receptor subfamily 4, group A, member 1 (Nr4a1), Insulin-like growth factor 2 (Igf2), Peripheral myelin protein 22 (Pmp22), Lim and SH3 Protein 1 (Lasp1)), and four are repressed (Secreted frizzled related proteins 1 and 2 (Sfrp1 and Sfrp2), Macrophage inflammatory protein-1 gamma (Mip-1?), and Anti-mullerian hormone (Amh)). The majority of these represent novel downstream genes not previously reported as targets of Shh. The new target genes have a diverse range of functions, and include transcriptional regulators and molecules known to be involved in regulating cell growth or apoptosis. The corroboration of genes previously implicated in hedgehog signalling, along with the finding of novel targets, demonstrates both the validity and power of the C3H/10T1/2 system for Shh target gene discovery. The identification of novel Sonic hedgehog responsive genes provides candidates whose abnormal expression may be decisive in initiating tumour formation and future studies will investigate their role in development and disease. It is expected that such findings will provide vital clues to the aetiology of various human cancers, and that an understanding of their roles may ultimately provide greater opportunities in the future design of anti-tumour therapies.

Sonic hedgehog (Shh) is a secreted morphogen involved in patterning a wide range of structures in the developing embryo. When cells receive the Shh signal a cascade of effects begin which in turn regulate downstream target genes. The genes controlled by Sonic hedgehog provide messages instructing cells how to differentiate or when to divide. Disruption of the hedgehog signalling cascade leads to a number of developmental disorders and plays a key role in the formation of a range of human cancers. Patched, the receptor for Shh, acts as a tumour suppressor and is mutated in naevoid basal cell carcinoma syndrome (NBCCS). NBCCS patients display a susceptibility to tumour formation, particularly for basal cell carcinoma (BCC). The discovery of Patched mutations in sporadic BCCs and other tumour types further highlights the importance of this pathway to human cancer. The identification of genes regulated by hedgehog is crucial for understanding how disruption of this pathway leads to neoplastic transformation. It is assumed that the abnormal expression of such genes plays a large role in directing cells to divide at inappropriate times. Only a small number of genes controlled by Shh have been described in vertebrate tissues. In the work presented in this thesis a Sonic hedgehog responsive embryonic mouse cell line, C3H/10T1/2, was used as a model system for hedgehog target gene discovery. Known downstream target genes were profiled to determine their induction kinetics, building up a body of knowledge on the response to Shh for this cell type. During this work, it was discovered that C3H/10T1/2 cells do not become fully competent to respond to Shh stimulation until the cells reach a critical density, a factor that had to be taken into account when determining timepoints of interest for further investigation. Several techniques were employed to identify genes that show expression changes between Shh stimulated and control cells. In one of these techniques, RNA from cell cultures activated with Shh was used to interrogate cDNA microarrays, and this provided many insights into the downstream transcriptional consequences of hedgehog stimulation. Microarrays consist of thousands of spots of DNA of known sequence gridded onto glass slides. Experiments using this technology allow the expression level of thousands of genes to be measured simultaneously. Independent stimulation methods combined with northern blotting were used to investigate individual genes of interest, allowing genuine targets to be confirmed and false positives eliminated. This resulted in the identification of eleven target genes. Seven of these are induced by Sonic hedgehog (Thrombomodulin (Thbd), Glucocorticoid induced leucine zipper (Gilz), Brain factor 2 (Bf2), Nuclear receptor subfamily 4, group A, member 1 (Nr4a1), Insulin-like growth factor 2 (Igf2), Peripheral myelin protein 22 (Pmp22), Lim and SH3 Protein 1 (Lasp1)), and four are repressed (Secreted frizzled related proteins 1 and 2 (Sfrp1 and Sfrp2), Macrophage inflammatory protein-1 gamma (Mip-1?), and Anti-mullerian hormone (Amh)). The majority of these represent novel downstream genes not previously reported as targets of Shh. The new target genes have a diverse range of functions, and include transcriptional regulators and molecules known to be involved in regulating cell growth or apoptosis. The corroboration of genes previously implicated in hedgehog signalling, along with the finding of novel targets, demonstrates both the validity and power of the C3H/10T1/2 system for Shh target gene discovery. The identification of novel Sonic hedgehog responsive genes provides candidates whose abnormal expression may be decisive in initiating tumour formation and future studies will investigate their role in development and disease. It is expected that such findings will provide vital clues to the aetiology of various human cancers, and that an understanding of their roles may ultimately provide greater opportunities in the future design of anti-tumour therapies.

Este trabalho descreve um novo modelo murino para o estudo da infecção crônica pelo T. cruzi usando o clone Sylvio X10/4. A infecção crônica de camundongos C3H/HePAS é caracterizada por intensas lesões inflamatórias no coração que podem ser comparáveis às observadas na doença de Chagas humana. Lesões moderadas também estavam presente na musculatura estriada esquelética desses animais. No coração dos animais crônicos foram detectados parasitas viáveis, confirmando a hipótese de que o desenvolvimento da patologia cardíaca na doença de Chagas está diretamente relacionada com a persistência do T. cruzi no tecido inflamado. Em contraste, camundongos A/J cronicamente infectados desenvolvem lesões no fígado e no músculo estriado, enquanto que no coração, não foram observados lesões nem parasitas. A análise fenotípica das gerações F1 e F2 (A/J X C3H/HePAS) sugere que a predisposição genética para desenvolver lesões teciduais na infecção pelo T. cruzi é heterogênea uma vez que a patologia no coração e no fígado é segregada na geração F2. Nossos resultados corroboram a hipótese que a heterogeneidade na patologia observada em pacientes com a doença de Chagas (ausência ou presença de lesões cardíacas ou digestivas) pode ser atribuída a fatores genéticos. / This work describes a novel murine model of the chronic infection by T. cruzi using the clone Sylvio X10/4. The infection in the C3H/HePAS mouse strain is characterized by intense inflammatory lesions in the heart, which can be comparable to the observed in the human Chagas\' disease. Moderate striated muscle lesions are also present in C3H/HePAS mice. In the heart of the chronic animals viable parasites were detected, confirming the hypothesis that the development of the heart pathology in the Chagas\' disease is related to parasite persistence in the inflamed tissue. By contrast, in infected A/J mice, develop lesions in the liver and skeletal muscle, while in the heart, lesions nor parasites were not observed. The phenotypic analysis of the generations F1 and F2 (A/J X C3H/HePAS) mice suggests that the genetic predisposition to develop the inflammatory lesions caused by T. cruzi is heterogeneous because the heart and liver pathology segregate in the F2 generation. These findings raise the hypothesis that the pathology heterogeneity observed in humans with Chagas\' disease (absence and presence of cardiac or digestive chronic lesions) can be attributed to host genetic factors.

Made available in DSpace on 2016-08-19T17:47:11Z (GMT). No. of bitstreams: 1 ANILDES IRAN PEREIRA SOUSA.pdf: 116617 bytes, checksum: 14ba38e42bfb1dbd3eba6477cff88f65 (MD5) Previous issue date: 2008-04-16 / The babassu mesocarp (Orbignya phalerata, Arecaceae) is popularly used in Maranhão, northeast of Brazil, as food and as medicine. It was the aim of this work to evaluate the effect of the babassu mesocarp extract (BME) on the biochemical parameters in mice bearing Ehrlich Ascitic tumor. C3H/HePas (N = l0 for group) with age of 120 and 240 days, were treated orally with BME (2mg/mL) during 15 or 30 days. At the end of this period the animals received, by intraperitoneal route, l06 cells of Ehrlich tumor. The animals were sacrificed ten days after the tumor implantation, when it was obtained the serum and the tumoral cells. The total number of tumoral cells was quantified in Neubauer chamber with aid of an optic microscope. The concentration of cholesterol, LDL, HDL, VLDL, triglicérides, total proteins and albumin was determined in serum, by colorimetric assay. The oral treatment with BME significantly increases on the number of tumoral cells. BME also affect the lipidic profile due to a strong reduction on the concentration of total cholesterol and HDL, LDL fractions. It was also observed a significant increase on the triglycerides concentration. Besides, the values of VLDL and total proteins were larger than the control in animals treated with EAB. Based on this, it is reasonable to propose that the reduction of cholesterol seems to be increased the tumor virulence. Additionally it was observed that BME induced a variable effect on blood biochemistry. Those results altogether makes BME unfeasible for using in the treatment of tumors with the same characteristics of the Ehrlich ascitic tumor. / O mesocarpo de babaçu (Orbignya phalerata, Arecaceae) é popularmente usado no Maranhão, nordeste do Brasil, como alimento e medicamento. Esse trabalho avaliou o efeito do tratamento com extrato bruto aquoso do mesocarpo de babaçu (EAB) na bioquímica sanguinea de camundongos C3H/HePas que desenvolveram o tumor de Ehrlich. Camundongos C3H/HePas (n= l0 por grupo), com idade de 120 e 240 dias, receberam, via oral, ad libitum, EAB (2mg/mL) durante 15 ou 30 dias. Em seguida ao último dia do tratamento os animais receberam, via intraperitoneal, l06 células de tumor de Ehrlich. Os animais foram sacrificados dez dias após a implantação do tumor, quando foram obtidos o soro e as células tumorais. As células foram quantificadas em câmara de Neubauer com auxílio de microscópio ótico de luz comum e o soro foi utilizado para determinar, por ensaios colorimétricos, a concentração de colesterol, triglicérides, proteínas totais e albumina. O tratamento com EAB induziu aumento significativo no número de células tumorais em camundongos C3H/HePas. A determinação do perfil lipídico mostrou que o tratamento com EAB resultou na redução da concentração de colesterol total e das frações HDL, LDL e no aumento da concentração de triglicérides . Além disso, os valores de VLDL e de proteínas totais foram maiores do que o controle em animais tratados previamente com EAB. Assim, é possível concluir que o tratamento oral com EAB aumenta a invasividade do tumor, possivelmente por reduzir a concentração de colesterol. Adicionalmente, o consumo de EAB tem efeitos variáveis sobre alguns parâmetros bioquímicos do sangue, dependendo da idade e do tempo de tratamento, o que inviabiliza o seu uso no tratamento de tumores com as mesmas características do tumor ascítico de Ehrlich.

Dans ce travail de thèse, nous nous sommes intéressés à la synthèse et l'utilisation d'outils chimiques pour l'étude des interactions intermoléculaires dans le domaine des nanostructures et dans celui de la biologie.<br />Dans ce but, nous avons développé une famille de molécules, les triazatrinaphthylènes (TrisK), se caractérisant par un large coeur aromatique ainsi que par la diversité des chaînes latérales qui peuvent y être introduites, leur nature gouvernant le type d'application désirée.<br />L'introduction de chaînes lipophiles confère aux TrisKs des propriétés d'auto-assemblage sur des surfaces. Les monocouches auto-assemblées obtenues sont étudiées par microscopie à effet tunnel (STM). Ces études constituent un premier pas dans la caractérisation des TrisKs en tant qu'éventuels composants actifs dans le domaine des matériaux organiques.<br />La substitution des TrisKs par des chaînes aminées leur apporte de l'hydro-solubilité, les rendant particulièrement adaptés pour le ciblage d'une structure particulière d'ADN,<br />l'ADN G-quadruplexe. Cette structure est actuellement étudiée de manière intensive pour son rôle central dans ce qui pourrait constituer une nouvelle stratégie anti-cancéreuse. Nous avons également développé l'utilisation de complexes de platine pour interagir sélectivement avec ces structures.

Els oòcits de vertebrats es troben aturats a la profase I de la primera meiosi (PI). Durant el procés anomenat oogènesi, els oòctits sintetitzen i emmagatzemen grans quantitats d'ARN missatgers(ARNm)que els seran necessaris per la compleció de la meiosi.I,per posteriorment, aturar-se de nou a la metafase de la segona divisió meiòtica (MII) per l'activitat del factor citostàtic(CSF).D'aquestes divisions en destaca el fet que transcorren en absència de transcripció, i per tant depenen totalment en l'activació traduccional dels ARNm anteriorment esmentats que han estat acumulats durant l'oogènesi. L'activació traduccional d'aquests missatgers és principalment induïda per l'elongació de les cues d'adenines(cues de poli(A)), aquest procés és mediat per les seqüències de poliadenilació citoplasmàtiques (CPE)presents a la regió 3' no tradudïda (3'UTR)dels ARNm. El moment i la longitud de la poliadenilació dels ARNm que contenen CPEs estan finament regulats, de manera que en combinació amb la degradació de proteïnes, s'estableixen els patrons específics d'expresió de les proteïnes que condueixen la meiosi (Shmitt et al., 2002; de Moor and Richter, 1997; Ballantyne et al., 1997; Mendez et al., 2002; Charlesworth et al., 2002). Fins a la data, no s'havia descrit que la deadenilació (escurçament de la cua de poli(A)) fos necessària per la progressió meiòtica. En aquesta tesi s'ha descrit, a partir d'un cribatge d'abast genòmic, una ruta de retroalimentació negativa requerida per a la sortida de la primera metafase meiòtica. La nova ruta identificada, a més té la particularitat d'actuar a nivell traduccional regulant l'expressió de proteïnes que participen directament en la progressió meiòtica. L'element central d'aquesta nova ruta és la proteïna C3H-4, que a la vegada és regulada per poliadenilació citoplasmàtica. C3H-4 crea la retroalimentació negativa interaccionant amb elements ARE de les regions 3'UTR, promovent la deadenilació del ARNm al qual s'uneix. D'entre les seves dianes hem identificat Emi1 i Emi2, ambdós reguladors de l'activitat de l'APC/C, crítica per la divisió cel·lular.