Navegando por Autor "Martins, Helen Rodrigues"

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Clinical and laboratory status of patients with chronic Chagas disease living in a vector controlled area in Minas Gerais, Brazil, before and nine years after aetiological treatment.
(2009) Lana, Marta de; Lopes, Leonardo de Araújo; Martins, Helen Rodrigues; Bahia, Maria Terezinha; Assis, Girley Francisco Machado de; Wendling, Ana Paula Barbosa; Martins Filho, Olindo Assis; Montoya, Roberto Araújo; Dias, João Carlos Pinto; Viñas, Pedro Albajar; Coura, José Rodrigues
Twenty-eight Chagas disease patients (CD), 22 with the indeterminate clinical form (IND) and six with the cardiac or digestive form (CARD/DIG), were treated with benznidazole and underwent clinical and laboratorial analysis before (IND and CARD/DIG) and nine years after [patients after treatment (CDt), patients with the indeterminate clinical form at treatment onset (INDt) and with the cardiac or digestive form at treatment onset (CARD/DIGt)] treatment. The data demonstrate that 82.1% of CDt patients (23/28) remained clinically stable and 95.4% of the INDt (21/22) and 33.3% of the CARD/DIGt (2/6) patients showed unaltered physical and laboratorial examinations. The clinical evolution rate was 2%/year and was especially low in INDt patients (0.5%/year) relative to CARD/DIGt patients (7.4%/year). Positive haemoculture in treated patients was observed in 7.1% of the cases. None of the INDt (0/21) and 33.3% of the CARD/DIGt (2/6) patients displayed positive cultures. The PCR presented a positive rate significantly higher (85.2%, 23/27) than haemoculture and two samples from the same patient revealed the same result 57.7% of the patients. Conventional serology-ELISA on 16 paired samples remained positive in all individuals. Semi-quantitative ELISA highlighted significant decreases in reactivity, particularly in INDt relative to IND. Non-conventional serology- FC-ALTA-IgG, after treatment, showed positive results in all sera and 22 paired samples examined at seven and nine years after treatment, demonstrated significantly lower reactivity, particularly in INDt patients. This study was retrospective in nature, had a low number of samples and lacked an intrinsic control group, but the data corroborate other results found in the literature. The data also demonstrate that, even though a cure has not been detected in the none-treated patients, the benefits for clinical evolution were selectively observed in the group of INDt patients and did not occur for CARD/DIGt patients.
Development of a label-free immunosensor based on surface plasmon resonance technique for the detection of anti-Leishmania infantum antibodies in canine serum.
(2013) Souto, Dênio Emanuel Pires; Silva, Jussara Vieira; Martins, Helen Rodrigues; Reis, Alexandre Barbosa; Luz, Rita de Cássia Silva; Kubota, Lauro Tatsuo; Damos, Flavio Santos
In this work ,a surface Plasmon resonance (SPR) immune sensor was developed using an 11-mercaptoundecanoic acid (11-MUA) modified gold SPR sensor chip for the detection of anti- Leishmania infantum antibodies. The soluble antigens of L. infantum were securely immobilized on an SPR gold disk byan 11-MUA self-assembled monolayer. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) techniques were employed in the characterization of the antigenim mobilization. After the immune sensor construction, canine serum positive for visceral leishmaniasis was added to its surface and showed significant variation in the SPR angle, indicating excellent sensitivity of the technique for antigen–antibody interaction detection. Moreover, the addition of negative serum was accompanied by as maller response, demonstrating that the immunosensor shows good specificity against anti-L. infantum antibodies. Therefore, this work demonstrates the success ful development of an SPR sensor for anti- L. infantum antibodies detection in short time, showing a great perspective as asensing system of visceral leishmania sisinende micregions.
Effects of specific treatment on parasitological and histopathological parameters in mice infected with different Trypanosoma cruzi clonal genotypes.
(2004) Toledo, Max Jean de Ornelas; Bahia, Maria Terezinha; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Alves, Cíntia Fontes; Martins, Helen Rodrigues; Cruz, Ruth Elizabeth; Tafuri, Washington Luiz; Lana, Marta de
The goal of this study was to verify the effect of specific treatment on parasitological and histopathological parameters in mice experimentally infected with different Trypanosoma cruzi clonal genotypes. Twenty cloned stocks were selected, representative of the whole phylogenetic diversity of the protozoan and belonging to the clonal genotypes 19 and 20 (T. cruzi I) and 39 and 32 (T. cruzi II). The stocks were inoculated in 40 BALB/c mice divided into four groups: (i) treated with benznidazole, (ii) treated with itraconazole and (iii and iv) untreated control groups (NT) for each drug, respectively. Seven parameters related to parasitaemia curves and histopathological lesions were analysed. Four during the acute phase (AP) and three during both the AP and chronic phase (CP) of infection. Statistical comparison between benznidazole-treated and NT groups for the biological parameters showed significant differences for all genotypes. Benznidazole treatment led to lower patent period, maximum of parasitaemia, day of maximum parasitaemia and area under the parasitaemia curve for all genotypes analysed. Percentage of positive haemoculture during AP and CP was lower for genotypes 19 and 32. Tissue parasitism (TP) and inflammatory process (IP) during AP were lower for genotypes 19 and 32, respectively. In general, itraconazole treatment induced a smaller reduction in these same parameters between treated and NT animals in relation to benznidazole treatment. Our results indicate that phylogenetic divergence among T. cruzi clonal genotypes must be taken in account in chemotherapy and studies dealing with all aspects of the parasite and the disease.
Experimental benznidazole treatment of Trypanosoma cruzi II strains isolated from children of the Jequitinhonha Valley, Minas Gerais, Brazil, with Chagas disease.
(2015) Silva, Jaquelline Carla Valamiel de Oliveira e; Assis, Girley Francisco Machado de; Oliveira, Maykon Tavares de; Paiva, Nívia Carolina Nogueira de; Araújo, Márcio Sobreira Silva; Carneiro, Cláudia Martins; Martins Filho, Olindo Assis; Martins, Helen Rodrigues; Lana, Marta de
Trypanosoma cruzi strains from distinct geographic areas show differences in drug resistance and association between parasites genetic and treatment response has been observed. Considering that benznidazole (BZ) can reduce the parasite burden and tissues damage, even in not cured animals and individuals, the goal is to assess the drug response to BZ of T. cruzi II strains isolated from children of the Jequitinhonha Valley, state of Minas Gerais, Brazil, before treatment. Mice infected and treated with BZ in both phases of infection were compared with the untreated and evaluated by fresh blood examination, haemoculture, polymerase chain reaction, conventional (ELISA) and non-conventional (FC-ALTA) serologies. In mice treated in the acute phase, a significant decrease in parasitaemia was observed for all strains. Positive parasitological and/or serological tests in animals treated during the acute and chronic (95.1-100%) phases showed that most of the strains were BZ resistant. However, beneficial effect was demonstrated because significant reduction (p < 0.05%) and/or suppression of parasitaemia was observed in mice infected with all strains (acute phase), associated to reduction/elimination of inflammation and fibrosis for two/eight strains. BZ offered some benefit, even in not cured animals, what suggest that BZ use may be recommended at least for recent chronic infection of the studied region.
Genetic modulation in Be-78 and Y Trypanosoma cruzi strains after long-term infection in Beagle dogs revealed by molecular markers.
(2012) Veloso, Vanja Maria; Guedes, Paulo Marcos da Matta; Lana, Marta de; Martins, Helen Rodrigues; Carneiro, Cláudia Martins; Câmara, Antônia Cláudia Jácome da; D’Ávila, Daniella Alchaar; Caldas, Ivo Santana; Galvão, Lúcia Maria da Cunha; Chiari, Egler; Bahia, Maria Terezinha
The genetic profile of Trypanosoma cruzi was evaluated in parasite populations isolated from Beagle dogs experimentally infected with Be-78 and Y strains that present distinct biological and genetic characteristics. Molecular characterization of the isolates obtained 30 days and 2 years after infection was carried out. For typing MLEE, sequence polymorphisms of the mitochondrial cytochrome oxidase subunit II gene (COII) and RAPD profiles were used. The profiles of MLEE were the same for the parental Be-78 strains as their respective isolates. However, changes of MLEE profile were observed in two T. cruzi isolates from dogs inoculated with Y strain. Changes in the mitochondrial DNA (COII) and RAPD profiles of the Y strain were also observed. The dendogram constructed by UPGMA with RAPD results indicated two major branches. Global data show that the genetic modulation in polyclonal strains during the long-term infection occurred and was strain-dependent. This study still suggests that each host (here each dog) harbors a determinate T. cruzi population that may change or be modulated throughout long-term infection. This might to hinder the observation of correlation between the genetics of T. cruzi and their biological properties and behavior in different host species due to the complexity of the parasite-host interaction in which probably the genetic background of both should be considered.
Impact of dual infections on chemotherapeutic efficacy in balb/c mice infected with major genotypes of trypanosoma cruzi.
(2007) Martins, Helen Rodrigues; Silva, Rodrigo Moreira da; Valadares, Helder Magno Silva; Toledo, Max Jean de Ornelas; Veloso, Vanja Maria; Avelar, Danielle Marchetti Vitelli; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Bahia, Maria Terezinha; Martins Filho, Olindo Assis; Macedo, Andréa Mara; Lana, Marta de
The aim of this work was to investigate the impact of dual infections with stocks of Trypanosoma cruzi major genotypes on benznidazole (BZ) treatment efficacy. For this purpose, T. cruzi stocks representative of the genetic T. cruzi lineages, displaying different susceptibilities to BZ, belonging to the major T. cruzi genotypes broadly dispersed in North and South America and important in Chagas’ disease epidemiology were used. Therapeutic efficacy was observed in 27.8% of the animals treated. Following BZ susceptibility classification, significant differences were observed in dual infections on the major genotype level, demonstrating that combinations of genotypes 19 39 and genotypes 19 32 led to a shift in the expected BZ susceptibility profile toward the resistance pattern. Analysis on the T. cruzi stock level demonstrated that 9 out of 24 dual infections shifted the expected BZ susceptibility profile compared with the respective single infections, including shifts toward lower and higher BZ susceptibilities. Microsatellite identification was able to identify a mixture of T. cruzi stocks in 7.7% of the T. cruzi isolates from infected and untreated mice (6.9%) and infected and treated but not cured mice (9.0%), revealing in some mixtures of BZ-susceptible and -resistant stocks that the T. cruzi stock identified after BZ treatment was previously susceptible in single infections. Considering the clonal structure and evolution of T. cruzi, an unexpected result was the identification of parasite subpopulations with distinct microsatellite alleles in relation to the original stocks observed in 12.2% of the isolates. Taken together, the data suggest that mixed infections, already verified in nature, may have an important impact on the efficacy of chemotherapy.
Impacto de infecções mistas por clones de Trypanosoma cruzi pertencentes aos grupos genéticos principais sobre propriedades biológicas do parasito em camundongos BALB/C.
(Programa de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2005) Martins, Helen Rodrigues; Lana, Marta de
Oito estoques clonais de Trypanosoma cruzi, dois de cada umdos genótipos principais 19 e 20 (T. cruzi I), 39 (híbrido) e 32 (T. cruziII) foramcombinados em24 infecções mistas diferentes e estudadas emcamundongos BALB/c. Emcada uma das infecções mistas, os animais foraminoculados com5.000 tripomastigotas sanguíneos de cada clone por animal e comparados coma corresponde infecção monoclonal cujo inóculo foi de 10.000 tripomastigotas do clonepor animal. Foramanalisados oito parâmetros: percentual de infectividade, percentual de mortalidade e percentual de positividade da hemocultura, período pré-patente, período patente, pico máximode parasitemia, dia do pico máximode parasitemia e parasitemia. Três comparações foram realizadas: (a) infecção monoclonal x infecçãomista baseada nos valores esperados (b) infecção monoclonal x infecção mista baseada nos valores observados (c) valores esperados x valores observados para as infecções mistas. Ocorreramdiferenças significativas na maioira dos parâmetros estudados, tendo sido observadas diferentes percentagens de alterações, variando de 4,2 a 79,2%. A parasitemia foi o parâmetro que apresentou maior pencentagemde alteração ocorrendo empraticamente todas as combinações genotípicas de T. cruzi. Foi observado aumento significativo e moito misturas e diminuição em11, representando alterações em19 das 24 combinações. Em umdos casos, foi observado efeito inibitório recíproco completo de umclone sobre o outro. A análise dos outros quatros parâmetros assosiados a parasitemia também demonstraramdiferenças significativas entre os valores observados e esperados nas infecções duplas emdiferentes proporções: 45.83% para PPP, 62.5% para PP, 66.6% para PMP e 33.3% para DPMP. Quando esses parâmetros foramconsiderados em conjunto, 11, 14, 11, 11, 15 e seis diferenças entre os valores observados e esperados foramdetectadas nas combinações genotípicas 19+20, 19+39 19+32, 20+39, 39+32 e 20+32, respectivamente. O menor número de diferenças significativas ocorreu exatamente na mistura 20+32, comclones filogeneticamente mais distantes e biologicamente mais distintos. Esses resultados enfatizama importância de se considerar a possibilidade de ocorrência de infecções mistas e suas conseqüências para o hospedeiro, na patogênese e na evolução da doença de Chagas.
Impedimetric immunosensor for rapid and simultaneous detection of chagas and visceral leishmaniasis for point of care diagnosis.
(2020) Cordeiro, Taís Aparecida Reis; Martins, Helen Rodrigues; Franco, Diego Leoni; Santos, Fred Luciano Neves; Celedon, Paola Alejandra Fiorani; Cantuária, Vinícius Lopes; Lana, Marta de; Reis, Alexandre Barbosa; Ferreira, Lucas Franco
In this work, a dual detection system based on an impedimetric immunosensor was developed for the first time for the simultaneous detection of anti-Trypanosoma cruzi and anti-Leishmania infantum antibodies in human and dog serum samples. The IBMP 8.1 and rLci1A/rLci2B recombinant antigens were immobilized over the surface of dual screen-printed carbon electrodes (W1 and W2) modified with poly (4-hydroxyphenylacetic acid). Under optimized conditions, the immunosensor recognized specific interactions for anti-T. cruzi antibodies up to a dilution of 1:10,240 and for anti-L. infantum up to 1:5120 in canine serum samples. Relative standard deviation (RSD) values of 2.8% for W1 and 3.6% for W2 were obtained for T. cruzi (W1) and L. infantum antigen (W2) samples in three different electrodes for 3 days (n = 9). The immunosensor was stored at 4 ◦C for 8 weeks, with activity retention of 70.2% in W1 and 78.2% in W2. The results using the recombinant proteins revealed that all antigens discriminated between negative and positive samples (p < 0.0001) in both dog and human groups, as well as no cross-reactivity could be detected among sera with other infections. With this approach, immunosensor-based diagnostic tests achieved 100% accuracy, suggesting that the antigens are eligible to enter Phase-II studies.
In-house ELISA method to analyze anti-Trypanosoma cruzi IgG reactivity for differential diagnosis and evaluation of Chagas disease morbidity.
(2012) Santos, Lilian da Silva; Torres, Rosália Morais; Assis, Girley Francisco Machado de; Bahia, Maria Terezinha; Martins, Helen Rodrigues; Carvalho, Andréa Teixeira de; Reis, Jordana Grazziela Alves Coelho dos; Viñas, Pedro Albajar; Martins Filho, Olindo Assis; Lana, Marta de
O objetivo foi desenvolver um método sorológico in-house de alta especificidade e sensibilidade para diagnosticar e monitorar a morbidade da doença de Chagas. Métodos: Para tal, a reatividade sorológica de IgG e subclasses foi testada em soros de pacientes chagásicos de Berilo, Vale do Jequitinhonha/MG/Brasil. A reatividade sorológica foi também avaliada em amostras de pacientes com outras doenças infecto-contagiosas relevantes, incluindo o HIV, vírus da hepatite C (VHC), sífilis (SYP), leishmaniose visceral (LV), leishmaniose tegumentar americana (LTA) e controles não infectados (NI) para verificar o desempenho do método. Outras análises foram feitas para avaliar a aplicabilidade desta metodologia no monitoramento da morbidade da doença de Chagas. Com este propósito os pacientes com doença de Chagas foram anteriormente classificados em três grupos: indeterminados (IND), cardíacos (CARD) e digestivos/mistos (DIG/Mis) conforme seu estado clínico. Resultados: A análise da reatividade sorológica de IgG total na diluição 1:40 mostrou ser uma abordagem importante no diagnóstico da doença de Chagas (100% de sensibilidade e especificidade e ausência de reação cruzada com as demais infecções). A análise das subclasses de IgG mostrou reação cruzada principalmente com NI, LV e LTA em todas as diluições. O grupo IND apresentou a maior reatividade para IgG3 e o grupo DIG/Mis apresentou nível mais elevado de IgG se comparados aos grupos IND e CARD. Conclusões: Estes achados demonstram que o método de ELISA in-house apresenta uma promissora aplicabilidade no diagnóstico diferencial e na avaliação da morbidade da doença de Chagas.
Label-free electrochemical impedance immunosensor based on modified screen-printed gold electrodes for the diagnosis of canine visceral leishmaniasis.
(2019) Cordeiro, Taís Aparecida Reis; Gonçalves, Marcus Vinícius do Carmo; Franco, Diego Leoni; Reis, Alexandre Barbosa; Martins, Helen Rodrigues; Ferreira, Lucas Franco
Leishmaniasis is a disease with high impact on public health in many countries. Visceral leishmaniasis (VL) is a vectorial zoonosis, with dogs as primary reservoirs in the domestic environment. VL presents high morbidity, mortality and importance in epidemiology in the American continent. In the present study, the first label-free electrochemical impedance immunosensor using screen-printed electrodes (SPEs) for the detection of anti-Leishmania infantum antibodies was developed. The soluble antigens of L. infantum were immobilized on an SPE by a 3-mercaptopropionic acid monolayer. Electrochemical impedance spectroscopy (EIS) was used for detecting bimolecular interactions occurring at the electrode surface. The addition of real samples consisting of canine and human sera positive and negative for VL presented high sensitivity and selectivity through EIS. Based on the results, a sensitive, specific, rapid and simple immunosensor was developed successfully with potential application for the serological diagnosis of leishmaniasis disease.
Molecular and biological characterization of Trypanosoma cruzi strains isolated from children from Jequitinhonha Valley, State of Minas Gerais, Brazil.
(2013) Silva, Jaquelline Carla Valamiel de Oliveira e; Assis, Girley Francisco Machado de; Oliveira, Maykon Tavares de; Valadares, Helder Magno Silva; Valle, Ítalo Faria do; Paiva, Nívia Carolina Nogueira de; Martins, Helen Rodrigues; Lana, Marta de
The biological diversity of Trypanosoma cruzi strains plays an important role in the clinical and epidemiological features of Chagas disease. Methods: Eight T. cruzi strains isolated from children living in a Chagas disease vector-controlled area of Jequitinhonha Valley, State of Minas Gerais, Brazil, were genetically and biologically characterized. Results: The characterizations demonstrated that all of the strains belonged to T. cruzi II, and showed high infectivity and a variable mean maximum peak of parasitemia. Six strains displayed low parasitemia, and two displayed moderate parasitemia. Later peaks of parasitemia and a predominance of intermediate and large trypomastigotes in all T. cruzi strains were observed. The mean prepatent period was relatively short (4.2±0.25 to 13.7±3.08 days), whereas the patent period ranged from 3.3±1.08 to 34.5±3.52 days. Mortality was observed only in animals infected with strain 806 (62.5%). Histopathological analysis of the heart showed that strains 501 and 806 caused infl ammation, but fi brosis was observed only in animals infected with strain 806. Conclusions: The results indicate the presence of an association between the biological behavior in mice and the genetic characteristics of the parasites. The study also confi rmed general data from Brazil where T. cruzi II lineage is the most prevalent in the domiciliary cycle and generally has low virulence, with some strains capable of inducing infl ammatory processes and fi brosis.
Persistence of PCR-positive tissue in benznidazole-treated mice with negative blood parasitological and serological tests in dual infections with Trypanosoma cruzi stocks from different genotypes.
(2008) Martins, Helen Rodrigues; Moreira, Lílian Figueiredo; Silva, Jaquelline Carla Valamiel de Oliveira e; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Avelar, Danielle Marchetti Vitelli; Bahia, Maria Terezinha; Martins Filho, Olindo Assis; Macedo, Andréa Mara; Lana, Marta de
Objectives: To assess different methodologies to better define an early post-therapeutic cure criterion after benznidazole treatment in BALB/c mice following mixed infection with dual Trypanosoma cruzi genotypes. Methods: According to the classical cure criteria, animals were classified as treated not cured (TNC 5 76.4%), treated cured (TC 5 12.5%) and dissociated (DIS 5 11.1%) using parasitological [fresh blood examination (FBE), blood culture (BC) and blood PCR] and serological methods [conventional serology (CS-ELISA) and non-conventional serology (NCS-FC-ALTA)]. Tissues were also evaluated by PCR. Results: FBE was able to detect patent parasitaemia in only 18.1% of TNC and therapeutic failure was detected in 79.1% and 97.2% of TNC by BC and blood PCR, respectively. CS-ELISA should not be used before 3 months after treatment since it may lead to false-negative results. At 3 months after treatment with benznidazole, NCS-FC-ALTA was more efficient for categorizing the groups of treated mice. In the TNC group, although a decreased frequency of PCR-positive tissue was observed in several host tissues, increased positivity was also observed, despite the T. cruzi genotype combination. All TC animals presented at least two positive tissue-PCR results. Conclusions: Our results confirm that NSC-FC-ALTA and blood PCR are the most suitable methods to early detect therapeutic failure in acute murine T. cruzi infection. Additionally, our data show that BC positivity is highly dependent upon the T. cruzi genotype combination. Moreover, our findings demonstrated that PCR tests performed on tissues from animals considered cured after benznidazole treatment still detected T. cruzi DNA, most probably indicating residual infection.
Tratamento com benzonidazol em camundongos infectados com misturas de populações do Trypanosoma cruzi pertencentes aos genótipos principais.
(Programa de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2008) Martins, Helen Rodrigues; Lana, Marta de
O objetivo desse trabalho foi avaliar o impacto de infecções mistas por clones de Trypanosoma cruzi pertencentes aos quatro genótipos principais na eficácia terapêutica do Benzonidazol (BZ) em camundongos BALB/c. Para esta proposta, foram empregados dois clones do T. cruzi de cada genótipo com diferentes níveis de virulência e de susceptibilidade ao BZ, que foram combinados aos pares totalizando 24 misturas distintas avaliadas comparativamente às respectivas monoinfecções. O tratamento com BZ reduziu os níveis de parasitemia além de outros parâmetros relacionados na maioria das infecções mistas, exceto nas da combinação dos genótipos 39+32. As taxas de mortalidade dos animais tratados (IT) e seus controles (INT) não diferiram significativamente entre as monoinfecções e as infecções mistas. A cura após tratamento foi definida empregando o critério de cura clássico, proposto por Krettli & Brener (1982) por meio de métodos parasitológicos (exame de sangue a fresco-ESF, hemocultura-Hc e PCR no sangue) e sorológicos (ELISA e pesquisa de anticorpos antitripomastigotas vivos-AATV) e, permitiu classificar os animais em tratados não curados (TNC=72,2%), tratados curados (TC=19,1) e dissociados (DIS=8,7%). Em geral, o ESF apresentou baixa positividade para a detecção da falha terapêutica (18,1%). A Hc apresentou sensibilidade satisfatória para a maioria das infecções, exceto nos animais infectados com o genótipo 39 e com a combinação 39+32; enquanto a PCR foi o método parasitológico mais sensível, a despeito da diversidade genética do T. cruzi. Os dados demonstraram que a ELISA não deve ser utilizada em amostras coletadas antes de três meses após tratamento, uma vez que pode apresentar resultados falsos negativos. A AATV foi mais eficiente na categorização dos animais em relação à resposta terapêutica e na definição precoce de cura. Os dados do presente estudo elegem a AATV e a PCR em sangue como as técnicas mais adequadas para a definição precoce de cura após tratamento da fase aguda da infecção pelo T. cruzi no modelo murino. Um importante achado deste estudo foi a observação de resultados positivos da PCR em tecidos de animais considerados curados pelo critério clássico, sugerindo infecção residual. Uma importante questão levantada por esses resultados é se a cura parasitológica de fato existe. A avaliação dos perfis de susceptibilidade ao BZ das infecções mistas foi realizada pela comparação entre os índices de cura observado e o esperado e, revelou mudança em direção ao padrão de menor susceptibilidade ao BZ nas combinações 19+39 e 19+32. Entretanto, quando os resultados foram analisados em nível dos clones do T. cruzi, foram observadas mudanças em nove das 24 misturas tendo sido detectados tanto aumento como diminuição na susceptibilidade ao fármaco. A caracterização molecular da amostra Cuica cl1, até então considerada um clone, demonstrou ser constituída de fato por duas populações geneticamente distintas cuja dinâmica populacional pode mudar dependendo da manutenção laboratorial. Entretanto, essas duas populações não apresentaram diferenças no perfil de susceptibilidade ao BZ. Em geral, a PCR de microssatélites apresentou boa correlação com a análise de isoenzimas na identificação dos clones presentes nas amostras isoladas de animais TNC e INT e confirmou a relação filogenética previamente determinada entre os clones por meio das análises de isoenzimas e RAPD. Apesar da análise de microssatélites apresentar baixa eficiência na identificação dos clones diretamente no sangue e nos tecidos de animais INT e TNC, os resultados obtidos dessas amostras biológicas foram similares aos obtidos para clones caracterizados após o isolamento pela Hc. Foram detectadas misturas em 7,7% dos isolados provenientes de animais INT e TNC obtidos por Hc. Em algumas misturas, resultados interessantes foram detectados revelando a presença do clone mais susceptível nas monoinfecções. Considerando a estrutura clonal do T. cruzi, um resultado inesperado foi a identificação de 15,5% dos isolados apresentando subpopulações do parasito com alelos de microssatélites distintos comparados aos clones originais. Esses achados sugerem que em alguns casos o tratamento com Benzonidazol pode resultar em um desequilíbrio da relação parasito-hospedeiro e levar ao estabelecimento de um curso da infecção distinto. Em conjunto, esses achados sugerem que infecções mistas podem apresentar um importante impacto na eficácia terapêutica. Estudos futuros são necessários para o melhor entendimento dos mecanismos envolvidos nas mudanças genéticas e no perfil de susceptibilidade ao Benzonidazol observado nas infecções mistas e o real benefício do tratamento para o hospedeiro.
Trypanosoma cruzi : blood parasitism kinetics and their correlation with heart parasitism intensity during long-term infection of Beagle dogs.
(2008) Veloso, Vanja Maria; Guedes, Paulo Marcos da Matta; Andrade, Isabel Mayer de; Caldas, Ivo Santana; Martins, Helen Rodrigues; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Lana, Marta de; Galvão, Lúcia Maria da Cunha; Bahia, Maria Terezinha; Chiari, Egler
The goals of the present study were to evaluate the kinetics of blood parasitism by examination of fresh blood, blood culture (BC) and PCR assays and their correlation with heart parasitism during two years of infection in Beagle dogs inoculated with the Be-78, Y and ABC Trypanosoma cruzi strains. Our results showed that the parasite or its kDNA is easily detected during the acute phase in all infected animals. On the other hand, a reduced number of positive tests were verified during the chronic phase of the infection. The frequency of positive tests was correlated with T. cruzi strain. The percentage of positive BC and blood PCR performed in samples from animals inoculated with Be-78 and ABC strains were similar and significantly larger in relation to animals infected with the Y strain. Comparison of the positivity of PCR tests performed using blood and heart tissue samples obtained two years after infection showed two different patterns associated with the inoculated T. cruzi strain: (1) high PCR positivity for both blood and tissue was observed in animals infected with Be-78 or ABC strains; (2) lower and higher PCR positivity for the blood and tissue, respectively, was detected in animals infected with Y strains. These data suggest that the sensitivity of BC and blood PCR was T. cruzi strain dependent and, in contrast, the heart tissue PCR revealed higher sensitivity regardless of the parasite stock.
Trypanosoma cruzi : effect of benznidazole therapy combined with the iron chelator desferrioxamine in infected mice.
(2008) Francisco, Amanda Fortes; Vieira, Paula Melo de Abreu; Arantes, Jerusa Marilda; Pedrosa, Maria Lúcia; Martins, Helen Rodrigues; Silva, Maísa; Veloso, Vanja Maria; Lana, Marta de; Bahia, Maria Terezinha; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
Iron chelators have been employed in various studies aimed at evaluating the relationship between the iron status of the host and the development of infection. In the present study, the effects of benznidazole (BZ) therapy in combination with the iron chelator desferrioxamine (DFO) on the development of infection in mice inoculated with Trypanosoma cruzi Y strain have been investigated. Infected mice treated with DFO presented lower levels of parasitemia compared with infected untreated animals. Therapy with BZ for 21 days, with or without DFO, led to decreased parasitemia and reduced mortality, but BZ in combination with DFO treatment for 35 days (BZ/DFO-35) gave 0% mortality. All infected groups presented lower levels of iron in the liver, but serum iron concentrations were greater in DFO-35 and BZ/DFO-35, whereas hemoglobin levels were higher in BZ/DFO-35 and lower in DFO-35 compared with other treated groups. The percentage cure, determined from negative hemoculture and PCR results in animals that had survived for 60 days post-infection, was 18% for BZ and BZ/DFO-35, 42% for BZ combined with DFO for 21 days, and 67% for DFO-35. The results demonstrate that modification in iron stores increases BZ efficacy.
Trypanosoma cruzi : immunoglobulin isotype profiles during the acute phase of canine experimental infection with metacyclic or blood trypomastigotes.
(2008) Vital, Wendel Coura; Carneiro, Cláudia Martins; Martins, Helen Rodrigues; Lana, Marta de; Veloso, Vanja Maria; Carvalho, Andréa Teixeira de; Bahia, Maria Terezinha; Oliveira, Rodrigo Corrêa de; Martins Filho, Olindo Assis; Tafuri, Wagner Luiz; Reis, Alexandre Barbosa
A detailed investigation has been carried out about the serological profiles of groups of dogs experimen-tally infected with metacyclic (MT) or blood (BT) trypomastigotes of Berenice-78 Trypanosoma cruzi strain. Peripheral blood was collected from infected dogs and uninfected controls, weekly during 35 days following the acute phase of infection, and immunoglobulin profiles were determined by ELISA. Dogs infected with BT exhibited unaltered levels of IgG2, increases in IgM, IgE, IgA, IgG and IgG1. In contrast, dogs infected with MT presented unaltered levels of IgE and IgG1 and an increase in IgM, IgA, IgG and IgG2 levels. Compared with the MT group, animals infected with BT showed significant increases in IgM on days 7, 14 and 28, in IgA on days 7, 14 and 21, in IgE on days 7 and 14, in IgG on days 14 and 28, and in IgG1 on days 7, 14 and 21. Parasitemia levels of the infected animals were measured over the same time period. No correlations were found between the immunoglobulin profiles and the parasi-temia levels. The results demonstrated that the inoculum source (BT or MT) influence the immunoglob-ulin isotype profile that may drive distinct outcome of acute canine Chagas disease
Trypanosoma cruzi : impact of dual-clone infections on parasite biological properties in BALB/c mice.
(2006) Martins, Helen Rodrigues; Toledo, Max Jean de Ornelas; Veloso, Vanja Maria; Carneiro, Cláudia Martins; Coelho, George Luiz Lins Machado; Tafuri, Washington Luiz; Bahia, Maria Terezinha; Valadares, Helder Magno Silva; Macedo, Andréa Mara; Lana, Marta de
Herein, we have analyzed major biological properties following dual-clone Trypanosoma cruzi infections in BALB/c mice. Eight T. cruzi clonal stocks, two of each principal genotype, including genotype 19 and 20 (T. cruzi I), hybrid genotype 39 (T. cruzi) and 32 (T. cruzi II) were combined into 24 diVerent dual-clone infections. Special attention was given to characterize biological parameters assayed including: prepatent period, patent period, maximum of parasitemia, day of maximum parasitemia, area under the parasitemia curve, infectivity, mortality, and hemoculture positivity. Our Wndings clearly demonstrated that features resultant of dual-clone infections of T. cruzi clonal stocks did not display either the characteristics of the corresponding monoclonal infections or the theoretical mixture based on the respective monoclonal infections. SigniWcant changes in the expected values were observed in 4.2–79.2% of the mixtures considering the eight biological parameters studied. A lower frequency of signiWcant diVerences was found for mixtures composed by phylogenetically distant clonal stocks. Altogether, our data support our hypothesis that mixed T. cruzi infections have a great impact on the biological properties of the parasite in the host and re-emphasizes the importance of considering the possible occurrence of natural mixed infections in humans and their consequences on the biological aspects of ongoing Chagas’ disease.
Trypanosoma cruzi : treatment with the iron chelator desferrioxamine reduces parasitemia and mortality in experimentally infected mice.
(2007) Arantes, Jerusa Marilda; Pedrosa, Maria Lúcia; Martins, Helen Rodrigues; Veloso, Vanja Maria; Lana, Marta de; Bahia, Maria Terezinha; Tafuri, Washington Luiz; Carneiro, Cláudia Martins
The effects of prolonged treatment with iron chelator (desferrioxamine) on the development of infection in mice inoculated with Y Trypanosoma cruzi were determined. Infected/treated mice presented lower levels of parasitemia and reduced mortality rate compared with infected/non-treated animals. The five out of twenty infected/treated mice that survived the acute phase of infection showed negative hemoculture and positive ELISA in the acute and chronic phases and positive PCR in the acute phase: in the chronic phase, three of the animals presented negative PCR. The single surviving infected/non-treated animal exhibited positive hemoculture, PCR and ELISA in both phases of infection. Infected groups presented lower levels of iron in the liver compared with treated/non-infected or non-treated/ non-infected animals. The serum iron levels of the infected/non-treated group were higher on the 21st day post-infection in comparison with control and infected/treated groups. These results suggest that decrease of iron in the host leads to T. cruzi infection attenuation.
Trypanosoma cruzi Discret Typing Units (TcII and TcVI) in samples of patients from two municipalities of the Jequitinhonha Valley, MG, Brazil, using two molecular typing strategies.
(2015) Oliveira, Maykon Tavares de; Assis, Girley Francisco Machado de; Silva, Jaquelline Carla Valamiel de Oliveira e; Machado, Evandro Marques de Menezes; Silva, Glenda Nicioli da; Veloso, Vanja Maria; Macedo, Andréa Mara; Martins, Helen Rodrigues; Lana, Marta de
Background: Trypanosoma cruzi is classified into six discrete taxonomic units (DTUs). For this classification, different biological markers and classification criteria have been used. The objective was to identify the genetic profile of T. cruzi samples isolated from patients of two municipalities of Jequitinhonha Valley, MG, Brazil. Methods: Molecular characterization was performed using two different criteria for T. cruzi typing to characterize 63 T. cruzi samples isolated from chronic Chagas disease patients. The characterizations followed two distinct methodologies. Additionally, the RAPD technique was used to evaluate the existence of genetic intragroup variability. Results: The first methodology identified 89 % of the samples as TcII, but it was not possible to define the genetic identity of seven isolates. The results obtained with the second methodology corroborated the classification as TcII of the same samples and defined the classification of the other seven as TcVI. RAPD analysis showed lower intra-group variability in TcII. Conclusions: The results confirmed the preliminary data obtained in other municipalities of the Jequitinhonha Valley, showing a predominance of TcII, similar to that verified in northeast/south axis of Brazil and the first detection of TcVI in the study region. The second protocol was more simple and reliable to identify samples of hybrid character.