Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2017-08-29T16:32:41Z No. of bitstreams: 2 Dissertação completa - CDALINE.pdf: 1677578 bytes, checksum: 70a6d704ab40032dc2f9a1952477236e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-08-29T16:32:41Z (GMT). No. of bitstreams: 2 Dissertação completa - CDALINE.pdf: 1677578 bytes, checksum: 70a6d704ab40032dc2f9a1952477236e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In the pharmaceutical area, plants and plant extracts are very important because they can serve as prototypes for the development of new drugs and as a source of pharmaceutical raw materials. Public health problems such as Chagas' disease and bacterial resistance to antimicrobials show a constant need for more efficient and safe drugs and active principles. In this context, the pharmacological study of plant species is extremely important. Among the plants with high medicinal potential, those of the genus Lonchocarpus stand out with several biological activities reported. The plant Lonchocarpus cultratus (Fabaceae) has proven action against sarcoma 180 and against Gram-positive bacteria. The main chemical constituents identified are cordoin, isocordoin, derricin and triterpenes. The objective of this study was to investigate the anti-bacterial action of the extracts of the seeds and roots from the L. cultratus species, to evaluate the anti-T.cruzi activity and the respective hemotoxicity of the extracts of the plant seeds and to carry out the chemical characterization of these extracts. The extracts hexane (LHS), dichloromethane (LDS) and methanolic (LMS) were obtained from plant seeds by successive macerations. The chemical characterization was performed by qualitative analytical methods and by 1H NMR. The anti-bacterial activity was evaluated by disc diffusion test, anti-T. Cruzi by direct counting method of the parasites in the Neubauer chamber and the hemotoxicity by UV method. Qualitative chemical tests showed that alkaloids, chalcones, coumarins, triterpenes and saponins are present in the roots and seeds of L. cultratus, flavonoids and steroids, only in the roots and tannins were not observed. Chalcones were identified by 1H NMR in LDS and LHS and steroids and terpenes in LMS. The LDS and LHS extracts showed activity against the epimastigote form of T. cruzi protozoan. The LDS results were better, showing inhibition of protozoan growth of 92.30% at the concentration of 175 μg.mL-1. The IC 50 value for this extract was 6.16 μg.mL-1 and at this concentration did not show toxicity to the red blood cells. The extracts studied did not present antimicrobial activity. The absence of anti-bacterial activity in the extracts of L. cultratus, especially in the root extract previously reported, suggests problems related to the stability or low concentration of bioactive chalcones in the extract. Although there is a need for additional research, anti-T. Cruzi and hemotoxicity obtained with the dichloromethane extract show an alternative potential for the treatment of Chagas' disease / Na área farmacêutica, as plantas e os extratos vegetais são muito importantes, pois podem servir como protótipos para o desenvolvimento de novos fármacos e como fonte de matérias-primas farmacêuticas. Problemas de saúde pública, como a doença de Chagas e a resistência bacteriana aos antimicrobianos, mostram a necessidade constante na busca de novos medicamentos e princípios ativos mais eficientes e seguros. Neste contexto, o estudo farmacológico de espécies vegetais é de extrema importância. Dentre as plantas com alto potencial medicinal, as do gênero Lonchocarpus destacam-se com diversas atividades biológicas relatadas. A planta Lonchocarpus cultratus (Fabaceae) possui ação comprovada frente ao sarcoma 180 e contra bactérias Gram-positivas. Os principais constituintes químicos identificados são a cordoina, a isocordoina, a derricina e triterpenos. Por ser uma planta pouco estudada e dando continuidade a estudos do grupo de pesquisa, o presente trabalho teve o objetivo de investigar a ação anti-bacteriana dos extratos das sementes e raízes da espécie L. cultratus, avaliar a atividade anti-T.cruzi e respectiva hemotoxicidade dos extratos das sementes da planta e realizar a caracterização química desses extratos. Os extratos hexânico (LHS), diclorometânico (LDS) e metanólico (LMS) foram obtidos de sementes da planta através de macerações sucessivas. A caracterização química foi realizada por meio de métodos analíticos qualitativos e por RMN 1H. A atividade anti-bacteriana foi avaliada por teste de difusão em disco, a anti-T. cruzi por método de contagem direta dos parasitas em câmara de Neubauer e a hemotoxicidade por método UV. Os testes químicos qualitativos mostraram que alcaloides, chalconas, cumarinas, triterpenos e saponinas estão presentes nas raízes e nas sementes da planta L. cultratus, flavonoides e esteroides, somente não foram observados nas raízes e taninos. Chalconas foram identificadas por RMN 1H, em LDS e LHS e esteroídes e terpenos em LMS. Os extratos LDS e LHS apresentaram atividade contra a forma epimastigota do protozoário T. cruzi. Os resultados do LDS foram melhores, mostrando inibição de crescimento do protozoário de 92,30% na concentração de 175 μg.mL-1. O valor de CI50 para este extrato foi 6,16 μg.mL-1 e nesta concentração não apresentou toxicidade para as hemácias. Os extratos estudados não apresentaram atividade antimicrobiana. A ausência de atividade anti-bacteriana nos extratos de L. cultratus, principalmente no extrato das raízes cuja propriedade foi reportada anteriormente, sugere problemas relacionados à estabilidade ou baixa concentração de chalconas bioativas no extrato. Embora haja necessidade de pesquisas adicionais, os resultados anti-T. cruzi e de hemotoxicidade obtidos com o extrato diclorometânico mostram potencial alternativa para o tratamento da Doença de Chagas.

A doença de Chagas possui uma importante relevância clínica, sendo uma das principais causas de mortalidade e morbidade na América Latina. As relações entre a lesão tecidual miocárdica e os defeitos na inervação autonômica na doença de Chagas são pouco conhecidas. Este trabalho descreve o desenvolvimento e aplicação de métodos de segmentação, corregistro e análise de imagens capazes de prover uma análise integrada das lesões teciduais através do imageamento de ressonância magnética (MRI), perfusão miocárdica e inervação autonômica, disponíveis através da tomografia de emissão de fótons (SPECT). O método proposto é baseado na segmentação e corregistro entre as imagens MRI e imagens SPECT usando 99mTc-MIBI e 123I-MIBG. Para realizar a segmentação do miocárdio, foi utilizada a técnica de Contorno Ativo Geodésico. A segmentação de fibrose em imagens MRI foi realizada com base na maximização da entropia de Tsallis. O corregistro não-rígido foi realizado através do método B-Spline. Os resultados de quantificação indicam correlações entre a presença de fibrose, desnervação e isquemia, além de mostrar a presença de regiões de miocárdio vivo, isquêmico e desnervado. Assim, a ferramenta desenvolvida fornece uma análise integrada de informação, permitindo uma melhor compreensão da relação entre o dano ao tecido do miocárdio e defeitos de inervação autonômica causadas pela doença de Chagas. / Chagas disease is of major clinical relevance, and a major cause of morbidity and mortality in Latin America. The relations between the myocardial tissue damage, myocardial perfusion and defects in autonomic innervations are poorly understood. This study proposes the development and application of image analysis methods capable of providing an integrated visualization and analysis of tissue injuries through enhanced magnetic resonance imaging (MRI), autonomic innervations and myocardial perfusion, available through photon emission tomography (SPECT). The proposed method is based on segmentation and registration between MRI images and SPECT images using 99mTc-MIBI and 123I-MIBG. To perform the segmentation of myocardium, we used Geodesic Active Contour. Fibrosis segmentation in MRI images was performed based on the algorithm of maximum Tsallis entropy. Nonrigid registrations was performed based on B-Spline method. The quantification results showed correlations between the presence of fibrosis, denervation and ischemia, as well as showing the regarded presence of regions of healthy myocardium, ischemic and denervated. Thus, the developed tool provides an integrated analysis of information contributing to a better understanding of the relationship between myocardial tissue damage and autonomic innervations injuries caused by Chagas disease.

Este trabalho apresenta a síntese de complexos de ouro(III) com ligante (dietilaminotiocarbonil)benzimidoíla-morfolinil-tiossemicarbazona e co-ligante L variando entre Cl-, CN-, SCN-, C3H5OS2- e C9H13N. Para a caracterização destes complexos foram envolvidas diversas técnicas, como espectroscopia na região do infravermelho e do UV-Vis, ponto de fusão, condutividade, espectroscopia de ressonância magnética nuclear 1H e 13C, espectrometria de massas ESI(+)-MS e análise elementar (C,H,N). O estudo consiste na avaliação da influência do ligante L frente a atividade antitumoral e anti-Trypanossoma cruzi, assim como na avaliação de sua influência em interações com possíveis alvos biológicos (DNA e albumina). Nos experimentos biológicos foi verificada a potencial atividade antitumoral destes complexos em células HepG2, HeLa, DU-145 e MDA-MB-231, dando destaque aos resultados obtidos para os complexos do tipo [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) e [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) frente à célula MDA-MB-231, ao complexo [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) frente à célula DU-145 e ao complexo [AuSCN(dmstc)] o qual apresentou resultados promissores para todas as linhagens celulares tumorais avaliadas. Os ensaios in vitro contra cepas Tulahuen LacZ de Trypanossoma cruzi apresentaram resultados promissores, demonstrando uma elevada atividade contra o parasita e citotoxicidade geral negligenciável frente à células de baço de camundongo Swiss para todos os complexos avaliados, com exceção do complexo [Au(xant)(dmstc)]. Através do estudo de interação destes complexos com DNA-ct e albumina humana (HSA), é possível descartar o DNA como principal alvo biológico responsável pelas atividades observadas e sugerir uma adequada distribuição in vivo por meio da HSA. / This work describes the synthesis of gold(III) complexes with the ligand (diethylaminocarbonyl)benzimidoyl-morpholinyl thiosemicarbazone and the co-ligand L varying between Cl-, CN-, SCN-, C3H5OS2- and C9H13N. The complexes characterization involved various techniques such as melting point, conductivity, infrared, UV-Vis, 1H and 13C NMR spectroscopies, ESI(+)-MS mass spectrometry and elemental analysis (C, H, N). The study consists on the evaluation of the influence of the ligand L front anti-tumor and anti-Trypanosoma cruzi activities, as well as in assessing their influence on interactions with possible biological targets (DNA and albumin). The biological experiments showed potential antitumor activity for the complexes against HepG2, HeLa, DU-145 and MDA-MB-231 cells, especially the results obtained for the complexes of the type [AuCl(dmstc)] (IC50 = 8,05 ?molL-1) and [Au(xant)(dmstc)] (IC50 = 28,5 ?molL-1) against the MDA-MB-231 cell, the complex [AuCl(dmstc)] (IC50 = 8,37 ?molL-1) against the DU-145 cell, and the complex [AuSCN(dmstc)] which showed promising results for all tumor cells lines evaluated. In vitro assays against LacZ Tulahuen Trypanosoma cruzi presented promising results, showing high activity against the parasite with negligible general cytotoxicity against the Swiss mouse spleen cells in all evaluating complexes, except for complex [Au(xant)(dmstc)]. Through the studies of interaction of the complexes with DNA-ct and human albumin (HSA) can discard the DNA as the primary biological target responsible for the observed activities and suggest a proper distribution in vivo through the HSA.

Desde a identificação do vírus da imunodeficiência humana (HIV, do inglês Human Immunodeficiency Virus) como agente causador da Síndrome da Imunodeficiência Adquirida (AIDS ? do inglês Acquired Immunodeficiency Syndrome), a busca para tratamentos seguros e eficazes contra o HIV transformou-se no principal foco para a descoberta de uma nova droga em todo o mundo. A AIDS aparece como um dos principais problemas de saúde pública para as próximas décadas, onde será o maior determinante de mortalidade na faixa etária entre 20 e 50 anos em praticamente todos os países do mundo. Tendo como objetivo relacionar a atividade de compostos biflavonóides anti-HIV-1 com algumas de suas propriedades moleculares, serão utilizados métodos de Mecânica Molecular e Química Quântica. O método de cálculo semi-empírico AM1 foi empregado para calcular um conjunto de propriedades moleculares dos 14 compostos biflavonóides com atividade anti-HIV-1. A seguir utilizar-se-á métodos estatísticos com a finalidade de separar os 14 compostos em duas classes, ativos e não ativos, de forma que se relacione qual as propriedades, dentre as calculadas, são responsáveis pela atividade dos compostos biflavonóides estudados. As técnicas estatísticas utilizadas foram a Análise de Componentes Principais (PCA: Principal Components Analysis), Análise Hierárquica de Agrupamentos (HCA: Hierarquical Clusters Analysis) e Análise de Discriminates por Passos (SDA: Stepwise Discriminant Analysis). Os estudos com PCA, HCA, e SDA mostraram que as variáveis HOMO (Highest Occupied Molecular Orbital - Orbital Molecular Ocupado de Maior Energia), LUMO (Lowest Unoccupied Molecular Orbital ? Orbital Molecular Desocupado de Menor Energia), e Área superficial são responsáveis pela separação dos compostos com alta e baixa atividade anti-HIV-1. O comportamento destas três propriedades pode ser útil na tentativa de se obter outros compostos biflavonóides com elevada atividade inibidora anti-HIV-1. / A set of 25 quinone compounds with anti-trypanocidal activity was studied by using the Density Functional Theory (DFT) method in order to calculate electronic atomic and molecular properties to be correlated with the biological activity. The chemometric methods Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), Stepwise Discriminant Analysis (SDA), Kth nearest neighbor (KNN) and Soft Independent Modeling of Class Analogy (SIMCA) were used to obtain possible relationships between the calculated descriptors and the biological activity studied and predict the anti-trypanocidal activity of new quinone compounds from a test set. Four descriptors were responsible for the separation between the active and inactive compounds: T5 (torsion angle), HOMO-1 (energy of the first molecular orbital below HOMO), QTS1 (sum of absolute values of the atomic charges) and VOLS2 (volume of the substituent at region B). These descriptors give information on the kind of interaction that occurs between the compounds and the biological receptor. The prediction study was done with a set of three new quinone compounds by using the PCA, HCA, SDA, KNN and SIMCA. Beside the five chemometric methods, the neural network method was used by employing the backpropagation algorithm. The four variables (T5, QTS1, VOLS2 and HOMO-1) were employed to validate the models constructed previously. The architecture of networks consisting of four neurons at input layers, ten neurons at intermediary layers and two neurons at output layers was adopted to observe the root mean square error between the true and desired output over the entire training set. The percentage of correct classification was 87.5%, and only one compound was predicted wrong in the test set, which indicates that the model is robust and could be able to make predictions. The docking studies were carried out with two different programs in the approach of ligands: the Autodock and FlexX. The docking results on trypanothione reductase enzyme showed that all studied compounds stay at second hydrophobic pocket in the outer region of the active site called the Z-site. The residues that could be specifically involved in the binding of ligands are Lys62, Thr66, Thr397, Thr463, Leu399, Ser464, Glu466 and Glu467, where the residues Thr66, Thr463 and Leu399 are conserved in different trypanothiones and could be used for the development of selective inhibitors against to the parasite enzyme.

A doença de Chagas, transmitida pelo protozoário Trypanosoma cruzi, afeta mais de 18 milhões de pessoas na América Latina e mesmo tendo sido descrita há 100 anos por Carlos Chagas, esta ainda representa um importante problema de saúde pública, sendo encontrados casos em 18 países em desenvolvimento na América do Sul e Central. No Brasil, o benzonidazol, (ROCHAGAN), é a única droga de atividade tripanocida disponível no mercado mesmo apresentando vários efeitos colaterais e limitada eficácia na fase crônica da infecção. Em vista da necessidade de novas substâncias com atividade biológica sobre T.cruzi, o interesse pela pesquisa vem crescendo com o intuito de se obter compostos capazes de atuarem sobre o parasita, desprovidos dos graves efeitos colaterais. Estudos desenvolvidos em nosso laboratório envolvendo lignanas demonstraram uma importante atividade destes compostos sobre as formas tripomastigotas sanguíneas. Assim este estudo tem como objetivo avaliar a atividade terapêutica de derivados de lignana dibenzilbutirolactônicas em sistema in vivo, em fase aguda e crônica da infecção por T. cruzi. Como critérios de estudo avaliamos o comportamento parasitêmico dos animais na fase aguda, quantificamos a enzima -galactosidase nos tecidos do fígado, baço e coração além da análise morfométrica dos tecidos. Com relação à parasitemia, dos animais na fase aguda, as substâncias cubebina e hinoquina, apresentaram significante redução parasitêmica comparado ao controle negativo e melhor atividade no tratamento pela via oral. Na análise por caracterização de -galactosidase, as substâncias apresentaram melhores resultados comparados ao controle positivo (Benzonidazol) e também melhor eficácia da resposta para o tratamento pela via oral. Nos resultados apresentados pela cariometria os grupos de tratamento com as substâncias cubebina e hinoquinina apresentaram valores próximos ao controle não infectado, mostrando que ocorreu uma resposta celular positiva comparado ao controle infectado. / Chagas disease, transmitted by the protozoan Trypanosoma cruzi, affects over 18 million people in Latin America. Even though it was described 100 years ago by Carlos Chagas, it still represents a major public health problem, and there are cases in 18 developing countries located in Central and South America. In Brazil, benznidazole (Rochagan) is the only trypanocidal drug available in the market; however, it has several side effects and limited efficacy in the chronic phase of the infection. In view of the need for new substances with biological activity against T. cruzi, there is growing interest in the search for compounds capable of acting on the parasite, but are devoid of serious side effects. Studies involving lignans developed in our laboratory have shown that these compounds are significantly active against bloodstream trypomastigotes. So this study aims to evaluate the therapeutic activity of derivatives of dibenzylbutyrolactone lignans in vivo, in the acute and chronic infection by T. cruzi. The present study examined the degree of parasitemia in the infected animals during the acute phase of the disease. To this end, the enzyme -galactosidase was measured in the tissues from the liver, spleen, and heart of infected animals, in addition to the morphometric analysis of these tissues. Cubebin and hinokinin led to significant reduction in parasitemia compared to the negative control, and better treatment was accomplished by the oral route. Concerning -galactosidase analysis, cubebin and hinokinin furnished better results compared to the positive control (Benznidazole), the most effective response to treatment being also achieved by oral route. Karyometry also revealed that cubebin and hinokinin were effective, giving values close to those obtained with the uninfected control, thereby showing that there was a positive cellular response.

A doença de Chagas é uma das doenças tropicais negligenciadas prioritárias para a Organização Mundial da Saúde (OMS). Endêmica na América Latina, é considerada atualmente um problema de saúde mundial, afetando diversos países na América do Norte, Europa, Ásia e Oceania. Estima-se que 8-10 milhões de pessoas estejam infectadas com o protozoário Trypanosoma cruzi. O tratamento disponível é limitado a dois fármacos que apresentam baixa eficácia e sérios efeitos adversos, o que torna evidente a urgência por novas alternativas terapêuticas. Esta dissertação de mestrado tem como objetivo o desenvolvimento de estudos das relações quantitativas entre a estrutura e atividade (QSAR, na sigla inglesa para quantitative structure-activity relationships) para duas séries de derivados do fenarimol com atividade anti-T. cruzi. Os compostos selecionados possuem considerável potência in vitro contra o parasita, além de atividade in vivo em modelos experimentais da doença, o que caracteriza o seu potencial para estudos em química medicinal. Neste contexto, estratégias de planejamento de fármacos foram utilizadas para a geração de modelos de QSAR preditivos. Foram utilizados os métodos holograma QSAR (HQSAR, na sigla inglesa para hologram QSAR); análise comparativa dos campos moleculares (CoMFA, na sigla inglesa para comparative molecular field analysis); e análise comparativa dos índices de similaridade estrutural (CoMSIA, na sigla inglesa para comparative molecular similarity indices). Os modelos gerados possuem alta capacidade de correlação interna e de predição externa, indicando também um conjunto de características estruturais responsáveis pela atividade anti-T. cruzi. Os resultados apresentados neste trabalho são úteis no planejamento de novos derivados do fenarimol com propriedades antichagásicas. / Chagas\' disease is considered by the World Health Organization (WHO) as one of the top neglected tropical diseases. Endemic in Latin America, it is currently a global public health problem, affecting several countries in North America, Europe, Asia and Oceania. The disease, caused by the protozoan parasite Trypanosoma cruzi, affects around 8-10 million people worldwide. The available treatment is limited to two drugs that present low efficacy and severe side effects, highlighting the urgent need for new therapeutic options. This masters dissertation focuses on the development of quantitative structure-activity relationships (QSAR) models for two series of fenarimol derivatives with activity against T. cruzi. The selected compounds exhibit substantial in vitro potency against the parasite, as well as in vivo activity in experimental models of the disease, which point out their potential for further studies in medicinal chemistry. In this context, drug design strategies were applied for the generation of predictive QSAR models. The methods employed were hologram QSAR (HQSAR); comparative molecular field analysis (CoMFA); and comparative molecular similarity indices (CoMSIA). The models possess high internal and external consistency, also indicating a set of structural features related to their anti-T. cruzi activity. The results reported herein are useful for the design of new fenarimol derivatives as new antichagasic agents.

Introdução: A morte súbita é a principal causa de morte na doença de Chagas, correspondendo de 55 a 65% dos casos. Observa-se que parte destas, ocorre em pacientes com função ventricular esquerda (FEVE) preservada, levando a acreditar que fatores desestabilizadores do substrato arritmogênico exercem um importante papel nestes eventos. Evidências já demonstraram a depressão parassimpática como fator contribuinte na gênese de arritmias diversas em presença de cardiopatia isquêmica. Assim, insiste-se na necessidade de se identificar precocemente quais os pacientes, no contexto da cardiopatia chagásica crônica, apresentam risco aumentado para o desenvolvimento de eventos arrítmicos complexos. Acredita-se que a avaliação autonômica identifique subgrupos distintos de risco. O presente estudo teve como objetivo determinar a sensibilidade do barorreflexo (SBR) em pacientes com doença de Chagas, nas formas indeterminada (GI) e arritmogênica com taquicardia ventricular não sustentada (GII) e com taquicardia ventricular sustentada (GIII) e, secundariamente, avaliar a associação entre a severidade da arritmia ventricular com o grau de comprometimento da SBR. Métodos: 42 pacientes foram submetidos à monitorização cardiovascular não invasiva pelo sistema Task Force ® onde foi determinada a SBR, utilizando o método da fenilefrina e analisada a variabilidade da frequência cardíaca (VFC) no domínio do tempo por meio da eletrocardiografia dinâmica de 24horas e a FEVE, por meio da ecocardiografia. Resultados: Observou-se diferença estatística significativa entre os grupos em relação à SBR em resposta à fenilefrina. O GIII apresentou o menor valor de SBR (6,09 ms/mmHg) quando comparado aos GII (11,84ms/mmHg) e GI (15,23ms/mmHg). Após comparação múltipla entre os grupos, verificou-se diferença significativa entre GI e GIII (p= 0,01). Quando se correlacionou SBR e densidade de extra-sístoles ventriculares (EV), observou-se que todos os pacientes portadores de baixa densidade de EV (< 10/hora) apresentavam SBR preservada (6,1ms/mmHg).Em contrapartida, entre aqueles com alta densidade de EV (>10/hora) somente 59% tinham SBR preservada (p=0,003). Nos pacientes com SBR deprimida (3,0-6,0 ms/mmHg) houve maior densidade de EV (p=0,01). Pacientes com SBR preservada apresentaram tanto função ventricular normal como moderadamente comprometida (66,7% com FEVE<40% e 79,5% com FEVE40%; p=0,62). O mesmo observou-se em pacientes com SBR moderadamente deprimida, (15,4% com FEVE<40% e 33,3% com FEVE40%; p=0,46). Não foi verificada correlação entre SBR e VFC. Ao se aplicar o modelo de regressão logística, observou-se que somente a SBR influenciou o aparecimento da taquicardia ventricular sustentada (p=0.028). Conclusão: A SBR está preservada na forma indeterminada da doença de Chagas e diminuída na forma arritmogênica. O comprometimento da SBR é progressivo e acompanha a evolução da doença, sendo mais intenso nos pacientes com arritmias ventriculares mais complexas. O grau de disfunção autonômica não se correlacionou com a função ventricular, mas, sim, com a densidade e a complexidade das arritmias / Introduction: Sudden death is the main cause of death in Chagas disease, corresponding to 55 to 65% of the cases. Some of these occur in patients with normal or almost normal left ventricular function (LVF), leading us to believe that factors that destabilize the arrhythmogenic substrate play an important role in these events. Evidences show parasympathetic depression to be a contributing factor in the genesis of diverse arrhythmias in the presence of ischemic heart disease. Thus, we insist on the need of an early identification of the patients, in the context of chronic Chagas heart disease, that are at increased risk of developing complex arrhythmic events. It is possible that autonomic assessment allows the identification of distinct risk subgroups. The objective of this study was to determine the baroreflex sensitivity (BRS) in patients with the indeterminate form of Chagas disease, (GI), and with the arrhythmogenic form of Chagas disease with nonsustained ventricular tachycardia (GII) and sustained ventricular tachycardia (GIII) and to assess the correlation between the severity of ventricular arrhythmia and the degree of BRS impairment. Methods: Forty-two patients were subjected to noninvasive cardiovascular monitoring using the Task Force® system. The phenylephrine method was used to determine BRS, 24- hour dynamic electrocardiography was used to analyze heart rate variability (HRV) over time and echocardiography was used to determine LVF. Results: A statistical difference was observed between the groups regarding their BRS to phenylephrine. GIII presented the lowest BRS value (6.09 ms/mmHg) when compared with GII (11.84ms/mmHg) and GI (15.23ms/mmHg). After multiple comparisons among the groups, a significant difference was found between GI and GIII (p=0.01). When BRS was correlated with ventricular extrasystole (VE) density, all patients who had low VE density (<10/hour) had preserved BRS (6.1ms/mmHg). On the other hand, only 59% of those with high EV density (>10/hour) had preserved BRS (p=0.003). In patients with moderately depressed BRS (3.0-6.0 ms/mmHg) there was a greater density of EV (p=0.01). Patients with preserved BRS had preserved or moderately compromised LVF (66.7% with LVF<40% and 79.5% with LVF40%; p=0.62) as had patients with moderately depressed BRS (15.4% with LVF<40% and 33.3% with LVF40%; p=0.46). There was no correlation between BRS and LVF. When the logistic regression model was applied, only BRS influenced the presence of sustained ventricular tachycardia (p=0.028). Conclusion: BRS is preserved in indeterminate Chagas disease and diminished in the arrhythmogenic form. The BRS impairment is progressive as the disease progresses, being more evident in patients with more complex ventricular arrhythmias. The degree of autonomic dysfunction did not correlate with ventricular function but with the density and complexity of the arrhythmias

This project describes and analyzes explanatory models of Chagas disease among people in a highly endemic area of eastern Bolivia, and examines the role that cultural and structural factors play in shaping explanatory models of this disease. Dressler (2001) characterizes medical anthropology as divided between two poles; the constructivist, which focuses on the "meaning and significance that events have for people," and the structuralist, which emphasizes the relationships between the components of a given society. This project endeavors to synthesize structuralist and constructivist perspectives by understanding the interaction between structural processes and explanatory models of Chagas disease. The research took place in the spring of 2013, in collaboration with the Centro Medico Humberto Parra, a non-profit clinic servicing low income populations in Palacios, Bolivia and surrounding communities. Semistructured interviews (n=68) and consensus analysis questionnaires (n=48) were administered to people dealing with Chagas disease, and free lists of possible treatments were collected. Overall, participants largely accepted the biomedical model, but also emphasized the emotional and social aspects of Chagas disease. The consensus analysis procedure indicated a clear shared model of Chagas disease, with coherent social, vector, symptoms, and ethnomedical domains. Furthermore, the model differed between groups based on ethnicity, gender, income and occupation. Significant differences were found in cultural knowledge of the disease based on community of residence and occupation status, two clear markers of how people are tied into the global economy. In the interviews, participants associate their Chagas disease with structural factors including poverty, rural living and traditional housing. They describe substantial barriers to getting biomedical care for their disease despite the existence of a free treatment program in Bolivia. However, participants reported numerous ethnomedical treatments; the study identified 39 ethnomedical treatments for Chagas disease and 66 for its cardiac symptoms. In sum, explanatory models include structural processes that shape disease, and are in turn influenced by these processes. In Bolivia, although structural constraints limit the scope of biomedical treatment, ethnomedical approaches to the disease are in a process of dynamic growth. The methods used here for assessing the structural component of the explanatory model of Chagas disease can be replicated in future research on explanatory models or political economy of health.

Trypanosoma cruzi, the etiologic agent of Chagas disease, infects a variety of wild mammals in the southern United States, but it has only recently been isolated from raccoons trapped in the state of Kentucky. The purpose of the present study was to use a molecular genotyping approach, followed by DNA sequencing to determine the genotypes (type I, or types IIa-IIe) of 15 of the Kentucky isolates. DNA samples were prepared from 15 T. cruzi- isolates using a Qiagen mini kit, and PCR amplification was performed using published primers for the 24S α rDNA sequence (D71 and D72), the non-transcribed spacer of the mini-exon genes (TC, TC1, and TC2), the 18S rDNA sequence (V1 and V2), and TCZ1 and TCZ2 primers that amplify a 188-base pair segment of the repetitive 195-bp nuclear DNA sequence of T. cruzi. DNA sequencing (ABI 3130 Genetic Analyzer) was performed on all amplification products obtained from the PCR analysis of the RW2 and RB12 isolates (randomly selected to represent both Warren and Barren counties of Kentucky; the number started with an “R” which stood for raccoon, a “W” for Warren County or a “B” for Barren County, followed by a number which represented the order in which animal was trapped). The resulting sequences were edited before analysis using the BLAST database of the National Center for Biotechnology Information (NCBI) Genbank. All 15 isolates were positively confirmed as T. cruzi based upon PCR amplification of a 195 bp repetitive genomic DNA sequence, and all 15 isolates showed identical PCR amplification results with all 4 sets of T. cruzi-specific primers. Two positive PCR samples were randomly selected for further DNA sequence analysis, and all samples were positively identified as the type IIa genotype of T. cruzi with max identities ranging from 94%-99%. The results of this study confirm that all hemoculture isolates obtained from raccoons trapped in Warren and Barren counties of Kentucky are T. cruzi. Furthermore, all BLAST comparisons of amplicon DNA sequences showed high sequence identity to type IIa strains of T. cruzi. The type IIa strain of T. cruzi is the most commonly reported genotype from raccoons trapped in the U.S.A.

Only 6 autochthonous cases of human Chagas disease have been documented in the U.S.A., however, as many as 5% of immigrants from Latin America may be infected with the etiologic agent, Trypanosoma cruzi. The parasite has been isolated from a variety of wild mammals, particularly in the southeastern region of the U.S.A. The goal of our study was to determine if the sylvatic cycle of T. cruzi infection occurs in Kentucky, and, if present, to assess the prevalence of infection in Warren and Barren counties. Raccoons and opossums were live-trapped between June and December, 2007. Animals were anesthetized with isoflurane, and blood samples were collected using a vacutainer system. Sera were frozen at -80oC for subsequent analysis, and whole blood samples were inoculated, in duplicate, into liver infusion tryptose (LIT) medium and cultured at 27oC. Seventeen T. cruzi isolates from raccoons have been positively identified by hemoculture. A total of 25/44 (57%) raccoon samples were found to be positive by hemoculture or serological analysis. In Warren County 18/25 (72%) of raccoons tested positive for T. cruzi and 7/19 raccoons (37%) in Barren County were positive for the parasite. Eighteen of 43 (42%) of the sera collected from opossums in Warren County and 3 of 5 (60%) from Barren County were judged to be positive by either enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay tests (IFAT). There were no positive hemoculture results for the opossum samples. The infection rates found in the current study for raccoons were slightly higher than those reported in previous studies in the U.S.A. However, the overall prevalence of T. cruzi in opossums (determined by serological analysis) was consistent with previous studies performed in the southeast. To our knowledge, this is the first report of T. cruzi from the state of Kentucky.