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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

"Análise imunohistoquímica do osteossarcoma em pacientes com e sem metástases e sua correlação prognóstica" / Immunohistochemistry analysis of osteosarcoma in patients with and without metastasis and its prognosis correlation

Abadi, Marcia Datz 06 December 2005 (has links)
As proteínas p53, MDM-2, c-Kit, ErbB-2, PCNA e p-glicoproteína foram estudadas em 42 amostras de osteossarcoma ao diagnóstico, através da técnica de imunohistoquímica, e foram correlacionados estes achados com o prognóstico destes pacientes. O p-53 foi positivo em 23,1% (9/39), PCNA em 71,4% (25/35), p-glicoproteína em 40,5% (15/37), MDM-2 em 34,8% (8/23), c-kit em 67,6% (25/37) e ErbB-2 em 17,9% (7/39). Na análise univariada, a presença de metástases ao diagnóstico, a positividade de p53 e ErbB-2 influenciaram o prognóstico individualmente, entretanto, na análise multivariada, a presença de metástase ao diagnóstico revelou-se o único fator de prognóstico estatisticamente significante / We study, by imunohistochemistry technique, the proteins p53, MDM-2, c-Kit, ErbB-2, PCNA and p-glycoprotein in samples of osteosarcoma tumors at diagnosis and its correlation with the prognosis of this patients. The p-53 was positive in 23,1% (9/39), PCNA in 71,4% (25/35), p-glycoprotein in 40,5% (15/37), MDM-2 in 34,8% (8/23), c-kit in 67,8%(25/37) and ErbB-2 in 17,9% (7/39) of the samples. In the univariate analysis, the presence of metastasis at diagnosis, the positivity of p-53 and ErbB-2 influenced the prognosis individually, otherwise, in the multivariate analysis, the presence of metastasis at diagnosis was the only prgnostic factor statistically significant
82

Trombofilias maternas hereditárias com e sem tromboembolismo venoso: resultados maternos e neonatais / Maternal inherited thrombophilias with or without venous thromboembolism: maternal and neonatal outcomes

André Luiz Malavasi Longo de Oliveira 06 July 2010 (has links)
O objetivo do presente estudo foi avaliar a diferença de resultados maternos e neonatais em gestações complicadas por trombofilias hereditárias em pacientes com e sem tromboembolismo venoso. Apesar do aumento de evidências, na literatura, sobre a associação de trombofilias congênitas e resultados obstétricos adversos, há ainda dúvida se pacientes trombofílicas com tromboembolismo venoso apresentam resultados maternos e neonatais piores que as pacientes trombofílicas sem tromboembolismo venoso. O estudo analisou 66 gestantes com trombofilias hereditárias, de forma retrospectiva observacional e comparativa, das quais 33 apresentavam tromboembolismo venoso e 36 o não apresentavam. Os principais desfechos relacionados a resultados maternos e neonatais adversos foram: pré-eclâmpsia grave, descolamento prematuro de placenta, restrição de crescimento fetal, natimortalidade, prematuridade e complicações hemorrágicas maternas. As trombofilias congênitas incluídas no estudo foram o fator V de Leiden (FVL), mutação da protrombina G20210A, mutação C677T do gene da 5,10-metilenotetrahidrofolato redutase (MTHFR), deficiência de proteína S, deficiência de proteína C e deficiência de antitrombina. Ambos os grupos apresentaram características populacionais similares. A ocorrência de complicações maternas e fetais/neonatais foi similar nos dois grupos: pré-eclâmpsia grave (P=0,097), descolamento prematuro de placenta (P=0,478), restrição de crescimento fetal (P=0,868), natimortalidade (P=0,359), prematuridade (P=0,441) e complicações hemorrágicas maternas (P=0,478). Este estudo concluiu que a presença de tromboembolismo venoso em gestantes com trombofilia hereditária apresenta resultados maternos e neonatais semelhantes àquelas com trombofilias hereditárias sem tromboembolismo venoso. / The aim of this study was to evaluate differences in maternal and neonatal outcomes in pregnancies complicated by inherited thrombophilias between patients with and without venous thromboembolism. Despite increasing evidence in the literature indicating an association between inherited thrombophilias and adverse obstetric outcomes, doubts remain whether thrombophilic patients with venous thromboembolism present poorer maternal and neonatal outcomes than thrombophilic patients without venous thromboembolism. In this retrospective, observational and comparative study, 66 pregnant women with inherited thrombophilias, including 33 with venous thromboembolism and 36 without thromboembolism, were investigated. The main end-points analyzed were severe pre-eclampsia, placental abruption, fetal growth restriction, stillbirth, preterm delivery, and maternal hemorrhagic complications. The congenital thrombophilias included in this study were factor V Leiden (FVL), prothrombin G20210A mutation, C677T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, protein S deficiency, protein C deficiency, and antithrombin deficiency. The two groups were similar in terms of population characteristics. The frequency of maternal and fetal/neonatal complications was similar in the two groups: severe pre-eclampsia (P=0.097), placental abruption (P=0.478), fetal growth restriction (P=0.868), stillbirth (P=0.359), preterm delivery (P=0.441), and maternal hemorrhagic complications (P=0.478). This study concluded that venous thromboembolism in thrombophilic patients does not worsen maternal or neonatal outcomes when compared to thrombophilic patients without venous thromboembolism.
83

Targeting breast cancer with natural forms of vitamin E and simvastatin

Gopalan, Archana 13 July 2012 (has links)
Breast cancer is the second leading cause of death due to cancer in women. A number of effective therapeutic strategies have been implemented in clinics to cope with the disease yet recurrent disease and toxicity reduce their effectiveness. Hence, there is a need to identify and develop more effective therapies with reduced toxic side effects to improve overall survival rates. This dissertation investigates the mechanisms of action of two natural forms of vitamin E and a cholesterol lowering drug, simvastatin, as a therapeutic strategy in human breast cancer cells. Vitamin E in nature consists of eight distinct forms which are fat soluble small lipids. Until recently, vitamin E was known as a potent antioxidant but emerging work suggests they may be resourceful agents in managing a number of chronic diseases including cancer. Anticancer properties of vitamin E have been identified to be limited to the γ- and δ- forms of both tocopherols and tocotrienols. Gamma-tocopherol ([gamma]T) and gamma-tocotrienol ([gamma]T3) have both already been identified to induce death receptor 5 (DR5) mediated apoptosis in breast cancer cells. Studies here show that similar to [gamma]T3, [gamma]T induced DR5 activation is mediated by c-Jun N-terminal kinase/C/EBP homologous protein (JNK/CHOP) proapoptotic axis which in part contributed to [gamma]T mediated dowregulation of c-FLIP, Bcl-2 and Survivin. Also, both agents activate de novo ceramide synthesis pathway which induces JNK/CHOP/DR5 proapoptotic axis and downregulates antiapoptotic factors FLICE inhibitory protein (c-FLIP), B-cell lymphoma 2 (Bcl-2) and Survivin leading to apoptosis. Simvastatin (SVA) has been identified to display pleiotropic effects including anticancer effects but mechanisms responsible for these actions have yet to be fully understood. In this dissertation, it was observed that simvastatin induced apoptosis in human breast cancer cells via activation of JNK/CHOP/DR5 proapoptotic axis and down regulation of antiapoptotic factors c-FLIP and Survivin which are in part dependent on JNK/CHOP/DR5 axis. The anticancer effects mediated by simvastatin can be reversed by exogenously added mevalonate and geranylgeranyl pyrophosphate (GGPP), implicating the blockage of mevalonate as a key event. Furthermore, work has been done to understand the factors responsible for drug resistance and identify therapeutic strategies to counteract the same. It was observed that development of drug resistance was associated with an increase in the percentage of tumor initiating cells (TICs) in both tamoxifen and Adriamycin resistant cells compared to their parental counterparts which was accompanied by an increase in phosphorylated form of Signal transducer and activator of transcription 3 (Stat3) proteins as well as its downstream mediators c-Myc, cyclin D1, Bcl-xL and Survivin. Inhibition of Stat3 demonstrated that Stat3 and its downstream mediators play an important role in regulation of TICs in drug resistant breast cancer. Moreover, SVA, [gamma]T3 and combination of SVA+[gamma]T3 has been observed to target TICs in drug resistant human breast cancer cells and downregulate Stat3 as well as its downstream mediators making it an attractive agent to overcome drug resistance. From the data presented here, the mechanisms responsible for the anticancer actions of [gamma]T, [gamma]T3 and SVA have been better understood, providing the necessary rationale to test these agents by themselves or in combination in pre-clinical models. / text
84

"Análise imunohistoquímica do osteossarcoma em pacientes com e sem metástases e sua correlação prognóstica" / Immunohistochemistry analysis of osteosarcoma in patients with and without metastasis and its prognosis correlation

Marcia Datz Abadi 06 December 2005 (has links)
As proteínas p53, MDM-2, c-Kit, ErbB-2, PCNA e p-glicoproteína foram estudadas em 42 amostras de osteossarcoma ao diagnóstico, através da técnica de imunohistoquímica, e foram correlacionados estes achados com o prognóstico destes pacientes. O p-53 foi positivo em 23,1% (9/39), PCNA em 71,4% (25/35), p-glicoproteína em 40,5% (15/37), MDM-2 em 34,8% (8/23), c-kit em 67,6% (25/37) e ErbB-2 em 17,9% (7/39). Na análise univariada, a presença de metástases ao diagnóstico, a positividade de p53 e ErbB-2 influenciaram o prognóstico individualmente, entretanto, na análise multivariada, a presença de metástase ao diagnóstico revelou-se o único fator de prognóstico estatisticamente significante / We study, by imunohistochemistry technique, the proteins p53, MDM-2, c-Kit, ErbB-2, PCNA and p-glycoprotein in samples of osteosarcoma tumors at diagnosis and its correlation with the prognosis of this patients. The p-53 was positive in 23,1% (9/39), PCNA in 71,4% (25/35), p-glycoprotein in 40,5% (15/37), MDM-2 in 34,8% (8/23), c-kit in 67,8%(25/37) and ErbB-2 in 17,9% (7/39) of the samples. In the univariate analysis, the presence of metastasis at diagnosis, the positivity of p-53 and ErbB-2 influenced the prognosis individually, otherwise, in the multivariate analysis, the presence of metastasis at diagnosis was the only prgnostic factor statistically significant
85

Contribution du test de génération de thrombine in vitro à l'étude des troubles de la coagulation dans le drépanocytose / Contribution of in vitro thrombin generation in the study of coagulation abnormalities in sickle cell disease

Noubouossie, Fondjie-Denis 05 June 2013 (has links)
La drépanocytose est associée à un état d’hypercoagulabilité qui se manifeste sur le plan clinique par un risque augmenté de thromboses artérielles et veineuses. L’exploration de la coagulation chez les patients drépanocytaires montrait surtout une activation de la coagulation et des altérations des acteurs pro- et anticoagulants du système hémostatique. Les tests de coagulation globale de routine tels que l’aPTT et le PT sont peu sensibles aux états d’hypercoagulabilité. La fonction hémostatique globale des patients drépanocytaires était donc peu connue. Le test de génération de thrombine est un test de coagulation globale, sensible aux états d’hypo- et d’hypercoagulabilité, facile à réaliser de nos jours avec une bonne reproductibilité. Nous l’avons utilisé pour démontrer que la coagulation globale des enfants drépanocytaires était caractérisée par une accélération des réactions de formation de la thrombine et par une augmentation du potentiel de thrombine endogène. Nous avons par la suite montré que les taux élevés de microparticules pro-coagulantes et du facteur VIII chez les enfants drépanocytaires seraient les facteurs déterminant l’accélération des réactions de formation de thrombine tandis que la réduction de l’activité anticoagulante du système protéine C / protéine S serait le facteur déterminant l’augmentation du potentiel de thrombine endogène. Les marqueurs de l’hémolyse corrélaient significativement avec ces facteurs ainsi qu’avec les paramètres de génération de thrombine, suggérant que l’hémolyse serait le mécanisme pathologique à la base de l’augmentation du potentiel de génération de thrombine chez les enfants drépanocytaires. Les paramètres de génération de thrombine n’étaient pas significativement différents entre l’état de stabilité clinique et l’état de crise vaso-occlusive. Chez les enfants hétérozygotes composites, ces paramètres avaient des valeurs intermédiaires entre celles des enfants contrôles et celles des enfants drépanocytaires homozygotes. Près de 40 % des enfants drépanocytaires homozygotes avaient un potentiel hémostatique supérieur à la moyenne + 2DS des enfants contrôles du même âge. Ces enfants présentant une génération de thrombine élevée se distinguaient des autres par leur plus jeune âge, une plus grande intensité de l’hémolyse, une plus courte durée de traitement par l’hydroxyurée et des vélocités du flux sanguin au doppler transcrânien plus élevées. Ces données suggèrent davantage un lien entre le potentiel de génération de thrombine et la vasculopathie cérébrale chez les enfants drépanocytaires. L’analyse de 4 enfants ayant reçu une greffe de cellules souches hématopoïétiques montrait une tendance à la réduction du potentiel de génération de thrombine et des autres altérations de la coagulation trois mois après la greffe. Le test de génération de thrombine permet une meilleure exploration de la coagulation globale des enfants drépanocytaires. Sa réalisation sur sang total permettrait une analyse plus globale en intégrant la participation des éléments figurés du sang particulièrement les globules rouges./<p>Sickle cell disease is associated with a hypercoagulable state that express clinically by an increased risk of arterial and venous thrombosis. The exploration of coagulation in sickle cell patients showed mainly activation of coagulation and alterations pro-and anticoagulants actors of the hemostatic system. Routine global testing of coagulation such as the prothrombin time and the activated partial thromboplastin time are insensitive to hypercoagulable states. The overall hemostatic function in sickle cell disease was so little known. The thrombin generation test is a test of overall coagulation. It is sensitive to both hypo- and hypercoagulable states. It is easy to perform nowadays with good reproducibility. We used it to demonstrate that the overall coagulation of sickle cell disease children was characterized by an acceleration of the reactions of thrombin formation and an increase of the endogenous thrombin potential. We have subsequently shown that high levels of procoagulant microparticles and high levels of factor VIII in children with sickle cell disease are the factors determining the acceleration of reactions leading to thrombin formation. Our results also showed that the reduced activity of the protein C / S anticoagulant pathway is a determining factor of the increased endogenous thrombin potential in sickle cell children. Markers of hemolysis correlated significantly with these factors as well as the parameters of thrombin generation, suggesting that hemolysis is probably the pathological mechanism underlying the increased potential for thrombin generation in children with sickle cell disease. Nearly 40% of children with homozygous sickle cell disease had their hemostatic potential above the mean + 2SD that of controls children of the same age. These children with high thrombin generation differed from others by their younger age, greater intensity of hemolysis, a shorter duration of treatment with hydroxyurea. They also had higher velocity of blood flow using transcranial Doppler. These data further suggest a potential link between thrombin generation and cerebral vasculopathy in children with sickle cell disease. Analysis of four children who received hematopoietic stem cells transplantation showed a tendency towards a reversibility of thrombin generation and other alterations of coagulation three months after the transplant. Thrombin generation assay allows a better exploration of the global coagulation of sickle cell disease children. Its realization on whole blood would be a more comprehensive analysis as it would integrate the participation of blood cells particularly red blood cells. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished
86

Estudo genético de pacientes portadores de cardiomiopatia hipertrófica / Genetic study of patients with hypertrophic cardiomyopathy

Marsiglia, Júlia Daher Carneiro 02 August 2013 (has links)
Introdução: A cardiomiopatia hipertrófica (CH) é uma doença genética cardíaca primária, caracterizada por hipertrofia do ventrículo esquerdo, sem dilatação, geralmente assimétrica e predominantemente septal, com prevalência estimada em 1:500. Atualmente já foram descobertos 20 genes associados à doença, mas os genes mais frequentemente relacionados são o da Cadeia Pesada da ?-miosina (MYH7), Proteína C de Ligação da Miosina (MYBPC3) e Troponina T (TNNT2). O diagnóstico molecular dos pacientes é importante e custo-efetivo do ponto de vista de saúde pública, além de recomendado pela Sociedade Europeia de Cardiologia. Entretanto, o custo inicial do exame é muito alto, de forma que estudos tentam reduzir esse custo. Uma das propostas descritas utilizou o RNA extraído de leucócitos para sequenciamento com sucesso para o gene MYBPC3. Este trabalho tem como objetivo testar a metodologia de sequenciamento de RNA em larga escala e testar a aplicabilidade da mesma para os genes MYH7 e TNNT2, estimar as principais mutações envolvidas nos pacientes do estudo e estabelecer correlações entre os diferentes genótipos avaliados e os fenótipos dos grupos familiares portadores da doença. Métodos: Os sujeitos incluídos no estudo são portadores de cardiomiopatia hipertrófica nos quais foi feita uma coleta de sangue para extração de DNA e RNA. Foi utilizada nested PCR para amplificação do cDNA e PCR convencional para amplificação de DNA e posterior sequenciamento em sequenciador automático. As análises estatísticas dos dados clínicos foram realizadas utilizando-se ANOVA para comparação de médias e teste exato de Fisher para comparação de frequências. Resultados: O sequenciamento de RNA se mostrou problemático, com baixa taxa de amplificação, falsos positivos e possíveis falsos negativos, de forma que optou-se por utilizar o sequenciamento de DNA para identificação das alterações. Dos 268 pacientes estudados foi identificada uma mutação em 131 deles (48,8%). Das mutações encontradas, 78 (59,5%) estavam no gene MYH7, 50 (38,2%) no gene MYBPC3 e 3 (2,3%) no gene TNNT2. Foram identificadas 69 mutações diferentes, 24 delas ainda não descritas. Pacientes com mutação identificada possuíam em média idade de diagnóstico e idade atual menores, maior frequência cardíaca média e maior frequência de pacientes com taquicardia ventricular não sustentada quando comparados ao grupo sem mutação identificada. Pacientes com mutação no gene MYH7 possuíam maior tamanho de átrio esquerdo, maior frequência de fibrilação atrial e maior frequência de histórico familiar da doença do que pacientes com mutação em MYBPC3. Conclusões: A técnica sequenciamento de RNA extraído de leucócitos não é adequada para uma rotina de rastreamento em larga escala para CH devido à alta frequência de falsos positivos, possibilidade de falsos negativos e baixa taxa de amplificação, mas o sequenciamento de DNA, embora trabalhoso, se mostrou muito sensível para a análise. A identificação de uma mutação específica ainda não pode ser usada para prognóstico de gravidade da CH, mas as comparações de genótipo e fenótipo mostraram algumas relações interessantes que devem ser melhor avaliadas nos pacientes. Este é o primeiro trabalho a caracterizar a epidemiologia molecular da CH em pacientes brasileiros para os genes MYH7, MYBPC3 e TNNT2 / Introduction: Hypertrophic cardiomyopathy (HC) is a primary genetic cardiac disease characterized by left ventricular hypertrophy without dilation, usually asymmetric and predominantly septal, with an estimated prevalence of 1:500. There are 20 genes associated to the HC, but the ones more often related to the disease are ?-myosin heavy chain (MYH7), myosin binding protein C (MYBPC3) and troponin T (TNNT2). The molecular diagnosis of patients is important and cost-effective from the standpoint of public health, and recommended by the European Society of Cardiology. However, the initial cost of the exam is very high, so several studies are attempting to reduce it. One of the proposals described used the RNA extracted from leukocytes for sequencing successfully to the MYBPC3 gene. The present study aims to test the methodology for large-scale sequencing and test it\'s applicability to the MYH7 and TNNT2 genes, to estimate the main mutations involved in the studied patients and establish correlations between their genotypes and phenotypes. Methods: The subjects included in the study were patients previously diagnosed with hypertrophic cardiomyopathy in whom a blood sample was collected to DNA and RNA extraction. It was used nested PCR for cDNA amplification and conventional PCR for DNA amplification for posterior sequencing on an automatic sequencer. Statistical analyzes of clinical data were performed using ANOVA to compare means and Fisher\'s exact test for frequencies comparison. Results: The RNA sequencing was problematic with low rate of amplification, false positives and possible false negatives, so was used DNA sequencing to identify the mutations. Of the 268 patients studied a mutation was identified in 131 of them (48.8%). Among the mutations found, 78 (59.5%) were in the MYH7 gene, 50 (38.2%) in the MYBPC3 gene and three (2.3%) in the TNNT2 gene. We have identified 69 different mutations, 24 of them not yet described. Patients with an identified mutation had an average smaller age of diagnosis and current age, higher average cardiac frequency and higher frequency of patients with nonsustained ventricular tachycardia compared to those without an identified mutation. Patients with mutations in the MYH7 gene had larger left atrium size, higher frequency of atrial fibrillation and higher frequency of family history of the disease than patients with a mutation in the MYBPC3 gene. Conclusions: The technique of sequencing RNA extracted from leucocytes is not suitable for large scale routine screening for CH due to the high frequency of false positives, possibility of false negatives and low rate of amplification, but the DNA sequencing, though laborious, was very sensitive to the analysis. Identification of a specific mutation cannot yet be used for prognosis of the disease\'s severity, but comparisons of genotype and phenotype have shown some interesting relationships that should be further evaluated. The presente study is the first one to characterize the molecular epidemiology of hypertrophic cardiomyopathy in Brazilian patients for those three more important genes mentioned above
87

Estudo genético de pacientes portadores de cardiomiopatia hipertrófica / Genetic study of patients with hypertrophic cardiomyopathy

Júlia Daher Carneiro Marsiglia 02 August 2013 (has links)
Introdução: A cardiomiopatia hipertrófica (CH) é uma doença genética cardíaca primária, caracterizada por hipertrofia do ventrículo esquerdo, sem dilatação, geralmente assimétrica e predominantemente septal, com prevalência estimada em 1:500. Atualmente já foram descobertos 20 genes associados à doença, mas os genes mais frequentemente relacionados são o da Cadeia Pesada da ?-miosina (MYH7), Proteína C de Ligação da Miosina (MYBPC3) e Troponina T (TNNT2). O diagnóstico molecular dos pacientes é importante e custo-efetivo do ponto de vista de saúde pública, além de recomendado pela Sociedade Europeia de Cardiologia. Entretanto, o custo inicial do exame é muito alto, de forma que estudos tentam reduzir esse custo. Uma das propostas descritas utilizou o RNA extraído de leucócitos para sequenciamento com sucesso para o gene MYBPC3. Este trabalho tem como objetivo testar a metodologia de sequenciamento de RNA em larga escala e testar a aplicabilidade da mesma para os genes MYH7 e TNNT2, estimar as principais mutações envolvidas nos pacientes do estudo e estabelecer correlações entre os diferentes genótipos avaliados e os fenótipos dos grupos familiares portadores da doença. Métodos: Os sujeitos incluídos no estudo são portadores de cardiomiopatia hipertrófica nos quais foi feita uma coleta de sangue para extração de DNA e RNA. Foi utilizada nested PCR para amplificação do cDNA e PCR convencional para amplificação de DNA e posterior sequenciamento em sequenciador automático. As análises estatísticas dos dados clínicos foram realizadas utilizando-se ANOVA para comparação de médias e teste exato de Fisher para comparação de frequências. Resultados: O sequenciamento de RNA se mostrou problemático, com baixa taxa de amplificação, falsos positivos e possíveis falsos negativos, de forma que optou-se por utilizar o sequenciamento de DNA para identificação das alterações. Dos 268 pacientes estudados foi identificada uma mutação em 131 deles (48,8%). Das mutações encontradas, 78 (59,5%) estavam no gene MYH7, 50 (38,2%) no gene MYBPC3 e 3 (2,3%) no gene TNNT2. Foram identificadas 69 mutações diferentes, 24 delas ainda não descritas. Pacientes com mutação identificada possuíam em média idade de diagnóstico e idade atual menores, maior frequência cardíaca média e maior frequência de pacientes com taquicardia ventricular não sustentada quando comparados ao grupo sem mutação identificada. Pacientes com mutação no gene MYH7 possuíam maior tamanho de átrio esquerdo, maior frequência de fibrilação atrial e maior frequência de histórico familiar da doença do que pacientes com mutação em MYBPC3. Conclusões: A técnica sequenciamento de RNA extraído de leucócitos não é adequada para uma rotina de rastreamento em larga escala para CH devido à alta frequência de falsos positivos, possibilidade de falsos negativos e baixa taxa de amplificação, mas o sequenciamento de DNA, embora trabalhoso, se mostrou muito sensível para a análise. A identificação de uma mutação específica ainda não pode ser usada para prognóstico de gravidade da CH, mas as comparações de genótipo e fenótipo mostraram algumas relações interessantes que devem ser melhor avaliadas nos pacientes. Este é o primeiro trabalho a caracterizar a epidemiologia molecular da CH em pacientes brasileiros para os genes MYH7, MYBPC3 e TNNT2 / Introduction: Hypertrophic cardiomyopathy (HC) is a primary genetic cardiac disease characterized by left ventricular hypertrophy without dilation, usually asymmetric and predominantly septal, with an estimated prevalence of 1:500. There are 20 genes associated to the HC, but the ones more often related to the disease are ?-myosin heavy chain (MYH7), myosin binding protein C (MYBPC3) and troponin T (TNNT2). The molecular diagnosis of patients is important and cost-effective from the standpoint of public health, and recommended by the European Society of Cardiology. However, the initial cost of the exam is very high, so several studies are attempting to reduce it. One of the proposals described used the RNA extracted from leukocytes for sequencing successfully to the MYBPC3 gene. The present study aims to test the methodology for large-scale sequencing and test it\'s applicability to the MYH7 and TNNT2 genes, to estimate the main mutations involved in the studied patients and establish correlations between their genotypes and phenotypes. Methods: The subjects included in the study were patients previously diagnosed with hypertrophic cardiomyopathy in whom a blood sample was collected to DNA and RNA extraction. It was used nested PCR for cDNA amplification and conventional PCR for DNA amplification for posterior sequencing on an automatic sequencer. Statistical analyzes of clinical data were performed using ANOVA to compare means and Fisher\'s exact test for frequencies comparison. Results: The RNA sequencing was problematic with low rate of amplification, false positives and possible false negatives, so was used DNA sequencing to identify the mutations. Of the 268 patients studied a mutation was identified in 131 of them (48.8%). Among the mutations found, 78 (59.5%) were in the MYH7 gene, 50 (38.2%) in the MYBPC3 gene and three (2.3%) in the TNNT2 gene. We have identified 69 different mutations, 24 of them not yet described. Patients with an identified mutation had an average smaller age of diagnosis and current age, higher average cardiac frequency and higher frequency of patients with nonsustained ventricular tachycardia compared to those without an identified mutation. Patients with mutations in the MYH7 gene had larger left atrium size, higher frequency of atrial fibrillation and higher frequency of family history of the disease than patients with a mutation in the MYBPC3 gene. Conclusions: The technique of sequencing RNA extracted from leucocytes is not suitable for large scale routine screening for CH due to the high frequency of false positives, possibility of false negatives and low rate of amplification, but the DNA sequencing, though laborious, was very sensitive to the analysis. Identification of a specific mutation cannot yet be used for prognosis of the disease\'s severity, but comparisons of genotype and phenotype have shown some interesting relationships that should be further evaluated. The presente study is the first one to characterize the molecular epidemiology of hypertrophic cardiomyopathy in Brazilian patients for those three more important genes mentioned above
88

Functional Characterization of Actin Sequestering Proteins in Plasmodium berghei

Hliscs, Marion 17 January 2012 (has links)
Plasmodien spp. sind obligat intrazellulär lebende Parasiten, welche einen evolutionär konservierten aktinabhängigen molekularen Motor für die Fortbewegung und den Wirtszellein- und -austritt nutzen. In dieser Arbeit werden die Aktinregulatoren Adenylyl- Zyklase- assoziierte Protein (C-CAP), Profilin sowie die Aktin depolymerizierenden Faktoren 1 und 2 (ADF1, ADF2) in Plasmodium berghei charakterisiert. Die Geninaktivierung von C-CAP besitzt keinen Einfluss auf die Entwicklung von pathogenen Blutstadien. C-cap(-) Ookineten bewegen sich jedoch deutlich langsamer, sind aber in der Lage den invertebraten Wirt zu infizieren. Defekte treten während der extrazellulären Replikationsphase im Mosquito auf und führen zu Abbruch des Lebenszykluses. Die erfolgreiche Komplementierung der Defekte mit dem orthologen Gen aus Cryptosporidium parvum CpC-CAP bestätigt die funktionale Redundanz zwischen beiden Proteinen. Profilin, als ein weiteres G-Aktin bindendes Protein, ist hingegen nicht in der Lage die Defekte des c-cap(-) Parasiten auszugleichen. Mittels transgener Parasiten welche ein C-CAPmCherry Fusionsprotein exprimieren, wird das C-CAP Protein im Zytoplasma lokalisiert. Erstmals wird mit dieser Arbeit ein G-Aktin bindendes Protein, C-CAP beschrieben, welches eine essentielle Funktion während der Oozystenreifung in Plasmodium berghei besitzt. Die Transkription der Aktinregulatoren Profilin, ADF1 und ADF2 wird in Sporozoiten drastisch herunterreguliert und Profilin kann als Protein nicht mehr nachgewiesen werden. Um die Funktion von C-CAP und Profilin zu überprüfen, wurden beide Proteine spezifisch in Sporozoiten überexprimiert. Diese Parasiten sind nicht in der Lage die Speicheldrüsen des Wirtes zu besiedeln, was zum Abbruch des Lebenszykluses führt. Anhand dieser Ergebnisse entwickele ich ein „minimalistisches“ Model zur Beschreibung der Aktinregulation in Sporozoiten in welchem das ADF1 als regulatorisches Protein im Mittelpunkt steht. / Plasmodium spp. are obligate intracellular parasites, which employ an conserved actin-dependent molecular motor machinery that facilitates their motility, host cell invasion and egress. In this work I report implications of the actin-regulators adenylyl cyclase-associated protein (C-CAP), profilin and actin depolymerization factor 1 and 2 (ADF1, ADF2) in distinct and previously unanticipated cellular processes during the life cycle of in the rodent malarial parasite Plasmodium berghei. Fluorescent tagging of the endogenous C-CAP genetic locus with mCherry revealed cytosolic distribution of the protein. Gene deletion demonstrates that the G-actin binding protein C-CAP is entirely dispensable for the pathogenic blood stages. Ookinetes show reduced motility, but are competent infecting the mosquito host. Defects emerging in the extracellular replication phase, leading to attenuation of oocyst maturation. Successful trans-species complementation with the C. parvum C-CAP ortholog, rescues the c-cap(-) phenotype and proves functional redundancy. The actin regulator profilin fails to rescue the defects of c-cap(-) parasites, despite sharing its actin sequestering activity with C-CAP. Taken together, C-CAP is the first G-actin sequestering protein of Plasmodium species that is not required for motility but performs essential functions during oocyst maturation. Characterization of the actin regulators profilin, ADF1 and ADF2 revealed dramatic transcriptional down-regulation and the absence of the profilin protein in sporozoites. To test whether G-actin binding proteins interfere with sporozoite functions, I ectopically overexpressed of profilin and C-CAP stage-specifically in sporozoites. This conducted to abolishment of salivary gland invasion and lifecycle arrest. Based on these unexpected findings and the available literature data, I developed a “minimalistic model” for actin regulation in sporozoites that predicts ADF1 as the main actin-turnover regulating factor.

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