DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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Item 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 deBackground: 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.Item Hematological alterations during experimental canine infection by Trypanosoma cruzi.(2012) Guedes, Paulo Marcos da Matta; Veloso, Vanja Maria; Mineo, Tiago Wilson Patriarca; Silva, Juliana Santiago; Crepalde, Geovam Pereira; Caldas, Ivo Santana; Nascimento, Manuela Sales Lima; Lana, Marta de; Chiari, Egler; Galvão, Lúcia Maria da Cunha; Bahia, Maria TerezinhaPara confirmar que cães Beagle são um bom modelo para doença de Chagas, foram avaliadas as alterações hematológicas durante as fases aguda e crônica em cães Beagle infectados com as cepas Y, Berenice-78 (Be-78) e ABC de Trypanosoma cruzi, correlacionando os sinais clínicos com a curva de parasitemia. Foi demonstrado que a fase aguda da infecção foi marcada por letargia e perda de apetite. Simultaneamente, observou-se anemia, leucocitose e linfocitose. Ainda, foram descritas alterações hematológicas e sinais clínicos positivamente correlacionados com a parasitemia durante a infecção experimental com as três cepas de T. cruzi estudadas, demonstrando que a infecção em cães Beagle constitui um modelo fidedigno para a doença de Chagas.Item IgG isotype profile is correlated with cardiomegaly in Beagle dogs infected with distinct Trypanosoma cruzi strains.(2008) Guedes, Paulo Marcos da Matta; Veloso, Vanja Maria; Gollob, Kenneth John; Afonso, Luís Carlos Crocco; Caldas, Ivo Santana; Vianna, Priscila; Lana, Marta de; Chiari, Egler; Bahia, Maria Terezinha; Galvão, Lúcia Maria da CunhaA systematic study following infection by various strains of the protozoan parasite, Trypanosoma cruzi, and the simultaneous monitoring of the humoral immune response together with the elicited cellular response, could add greatly to our understanding of differences between strains of this important human pathogen. In that sense, acute and chronic infections with distinct T. cruzi strains (Y, Berenice-78 and ABC) in Beagle dogs were studied through a longitudinal evaluation of immunoglobulin G (IgG), IgG1 and IgG2 isotypes (by ELISA and flow cytometry (FC)), as well as measurements of peripheral blood mononuclear cell (PBMC) proliferation over a 100-week period, and their correlation with cardiomegaly. Our results show that infected animals presenting cardiomegaly showed lower or absent levels of IgG1 during the chronic phase of the infection, when compared to those that did not show an increase in heart weight. In that manner, our results suggest that IgG1 could be used as a marker for cardiac pathogenicity in Chagas disease.Item Trypanosoma cruzi : induction of benznidazole resistance in vivo and its modulation by in vitro culturing and mice infection.(2008) Santos, Fabiane Matos dos; Caldas, Sérgio; Cáu, Stêfany Bruno de Assis; Crepalde, Geovam Pereira; Lana, Marta de; Coelho, George Luiz Lins Machado; Veloso, Vanja Maria; Bahia, Maria TerezinhaThrough a continuous in vivo drug pressure protocol, using mice as experimental model, we induced benznidazole resistance in Trypanosoma cruzi stocks. Full resistance was obtained for four out of five T. cruzi stocks analyzed. However, the number of benznidazole doses (40–180), as well as the time (4–18 months) necessary to induce resistance varied among the different T. cruzi stocks. The resistance phenotype remained stable after T. cruzi stocks has been maintained by 12 passages in mice (six months) and in acellular culture for the same time. However, the maintenance of resistant parasite for 12 months in acellular culture induces a reduction in its level of benznidazole resistance, while no alteration was detected in parasite maintained for the same time in mice. The data showed the stability of the resistance acquired by drug pressure, but suggest the possibility of reversible changes in the resistance levels after maintenance for long time in acellular culture.Item Trypanosoma cruzi : acute and long-term infection in the vertebrate host can modify the response to benznidazole.(2008) Caldas, Sérgio; Santos, Fabiane Matos dos; Lana, Marta de; Diniz, Lívia de Figueiredo; Coelho, George Luiz Lins Machado; Veloso, Vanja Maria; Bahia, Maria TerezinhaWe analyzed the influence of Trypanosoma cruzi maintenance in different hosts (dog and mouse) on its susceptibility to benznidazole treatment. Five T. cruzi stocks were isolated from dogs inoculated with Be-62 or Be-78 strain (both sensitive to benznidazole) 2–10 years ago, and the benznidazole sensitivity was then determined using the mouse as experimental model. The different T. cruzi stocks obtained from long-term infected dogs showed 50–90% drug resistance right after isolation. However, maintenance of these T. cruzi stocks in mice, by successive blood passages (2.5 years), led to either a decrease or stability of the drug resistance pattern and an increase in parasite virulence. We also demonstrated the effectiveness of the induction of parasitemia reactivation by cyclophosphamide immunosuppression in the evaluation of the response to the specific drug treatment.Item Myenteric plexus is differentially affected by infection with distinct Trypanosoma cruzi strains in Beagle dogs.(2014) Paiva, Nívia Carolina Nogueira de; Fonseca, Kátia da Silva; Vieira, Paula Melo de Abreu; Diniz, Lívia de Figueiredo; Caldas, Ivo Santana; Moura, Sandra Aparecida Lima de; Veloso, Vanja Maria; Guedes, Paulo Marcos da Matta; Tafuri, Washington Luiz; Bahia, Maria Terezinha; Carneiro, Cláudia MartinsChagasic megaoesophagus and megacolon are characterised by motor abnormalities related to enteric nervous system lesions and their development seems to be related to geographic distribution of distinct Trypanosoma cruzi subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T. cruzi strains and necropsied during the acute or chronic phase of experimental disease for post mortem histopathological evaluation of the oesophagus and colon. Both strains infected the oesophagus and colon and caused an inflammatory response during the acute phase. In the chronic phase, inflammatory process was observed exclusively in the Be-78 infected animals, possibly due to a parasitism persistent only in this group. Myenteric denervation occurred during the acute phase of infection for both strains, but persisted chronically only in Be-78 infected animals. Glial cell involvement occurred earlier in animals infected with the Y strain, while animals infected with the Be-78 strain showed reduced glial fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic phase. These results suggest that although both strains cause lesions in the digestive tract, the Y strain is associated with early control of the lesion, while the Be-78 strain results in progressive gut lesions in this model.