Complexation of the anti-Trypanosoma cruzi drug benznidazole improves solubility and efficacy

The ruthenium complex,trans-[Ru(Bz)(NH3)(4)SO2](CF3SO3)(2) 1, Bz = benznidazole (N-benzyl-2-(2-nitro-1H-imidazol-1-yl)acetamide), is more hydrosoluble and more active (IC50try/1 h = 79 +/- 3 mu M) than free benznidazole 2 (IC50try/1 h > 1 mM). 1 also exhibits low acute toxicity in vitro (IC50macrophages > 1 mM) and in vivo (400 mu mol/kg < LD50 < 600 mu mol/kg) and the formation of hydroxylamine is more favorable in 1 than in 2 by 9.6 kcal/mol. In murine acute models of Chagas` disease, 1 was more active than 2 even when only one dose was administrated. Moreover, 1 at a thousand-fold smaller concentration than the considered optimal dose for 2 (385 mu mol/kg/day = 100 mg/kg/day), proved to be sufficient to protect all infected mice, eliminating the amastigotes in their hearts and skeletal muscles as observed in H&E micrographics.

Expression, purification and kinetic characterization of His-tagged glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi

Trypanosomes are flagellated protozoa responsible for serious parasitic diseases that have been classified by the World Health Organization as tropical sicknesses of major importance. One important drug target receiving considerable attention is the enzyme glyceraldehyde-3-phosphate dehydrogenase from the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease (T. cruzi Glyceraldehyde-3-phosphate dehydrogenase (TcGAPDH); EC 1.2.1.12). TcGAPDH is a key enzyme in the glycolytic pathway of T. cruzi and catalyzes the oxidative phosphorylation of D-glyceraldehyde-3-phosphate (G3P) to 1,3-bisphosphoglycerate (1,3-BPG) coupled to the reduction of oxidized nicotinamide adenine dinucleotide, (NAD(+)) to NADH, the reduced form. Herein, we describe the cloning of the T. cruzi gene for TcGAPDH into the pET-28a(+) vector, its expression as a tagged protein in Escherichia coli, purification and kinetic characterization. The His(6)-tagged TcGAPDH was purified by affinity chromatography. Enzyme activity assays for the recombinant His(6)-TcGAPDH were carried out spectrophotometrically to determine the kinetic parameters. The apparent Michaelis-Menten constant (K(M)(app)) determined for D-glyceraldehyde-3-phosphate and NAD(+) were 352 +/- 21 and 272 +/- 25 mu M, respectively, which were consistent with the values for the untagged enzyme reported in the literature. We have demonstrated by the use of Isothermal Titration Calorimetry (ITC) that this vector modification resulted in activity preserved for a higher period. We also report here the use of response surface methodology (RSM) to determine the region of optimal conditions for enzyme activity. A quadratic model was developed by RSM to describe the enzyme activity in terms of pH and temperature as independent variables. According to the RMS contour plots and variance analysis, the maximum enzyme activity was at 29.1 degrees C and pH 8.6. Above 37 degrees C, the enzyme activity starts to fall, which may be related to previous reports that the quaternary structure begins a process of disassembly. (C) 2010 Elsevier Inc. All rights reserved.

Experimental Chemotherapy against Trypanosoma cruzi Infection Using Ruthenium Nitric Oxide Donors

The ruthenium NO donors of the group trans-[Ru(NO)(NH(3))(4)L](n+), where the ligand (L) is N-heterocyclic H(2)O, SO(3)(2 -), or triethyl phosphite, are able to lyse Trypanosoma cruzi in vitro and in vivo. Using half-maximal (50%) inhibitory concentrations against bloodstream trypomastigotes (IC(50)(try)) and cytotoxicity data on mammalian V-79 cells (IC(50)(V79)), the in vitro therapeutic indices (TIs) (IC(50)(V79)/IC(50)(try)) for these compounds were calculated. Compounds that exhibited an in vitro TI of >= 10 and trypanocidal activity against both epimastigotes and trypomastigotes with an IC(50)(try/epi) of <= 100 mu M were assayed in a mouse model for acute Chagas` disease, using two different routes (intraperitoneal and oral) for drug administration. A dose-effect relationship was observed, and from that, the ideal dose of 400 nmol/kg of body weight for both trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) (isn, isonicotinamide) and trans-[Ru(NO)(NH3) 4imN](BF4) 3 (imN, imidazole) and median (50%) effective doses (ED50) of 86 and 190 nmol/kg, respectively, were then calculated. Since the 50% lethal doses (LD(50)) for both compounds are higher than 125 mu mol/kg, the in vivo TIs (LD(50)/ED(50)) of the compounds are 1,453 for trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) and 658 for trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3). Although these compounds exhibit a marked trypanocidal activity and are able to react with cysteine, they exhibit very low activity in T. cruzi -glycosomal glyceraldehyde-3-phosphate dehydrogenase tests, suggesting that this enzyme is not their target. The trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) and trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) compounds are able to eliminate amastigote nests in myocardium tissue at 400-nmol/kg doses and ensure the survival of all infected mice, thus opening a novel set of therapies to try against trypanosomatids.

International study to evaluate PCR methods for detection of Trypanosoma cruzi DNA in blood samples from Chagas disease patients.

A century after its discovery, Chagas disease still represents a major neglected tropical threat. Accurate diagnostics tools as well as surrogate markers of parasitological response to treatment are research priorities in the field. The purpose of this study was to evaluate the performance of PCR methods in detection of Trypanosoma cruzi DNA by an external quality evaluation.

A reda����o de teses e disserta����es: estudo de aspectos ling����sticos e gram��ticais em monografias produzidas entre 1989 e 1993

Este trabalho trata de aspectos ling����sticos e gramaticais de teses de doutorado e de disserta����es de mestrado produzidas em uma escola superior de administra����o da cidade de S��o Paulo, no per��odo compreendido entre 1989 e 1993. O trabalho divide-se em tr��s partes. Na primeira, estudam-se as orienta����es de autores especializados na an��lise e na reda����o de textos. Com base em uma amostra de teses e disserta����es, examina-se como s��o - ou n��o - aplicadas nas frases essas orienta����es. S��o comentados os problemas de elabora����o de texto encontrados e s��o feitas recomenda����es. Na segunda parte, estudam-se as orienta����es de conceituados autores especializados em gram��tica normativa da l��ngua portuguesa. Com base na amostra das teses e disserta����es, examina-se como s��o aplicadas nos voc��bulos e nas frases essas orienta����es. S��o comentadas as dificuldades gramaticais encontradas e s��o feitas recomenda����es. S��o comentadas tamb��m dificuldades gramaticais da fala dos administradores. Na terceira parte, est��o as conclus��es suscitadas pelo exame da teoria e pelo exame da pesquisa realizada

Avalia����o do banco de disserta����es e teses da associa����o brasileira de antropologia: uma an��lise cienciom��trica

VITULLO, Nadia Aurora Vanti. Avalia����o do banco de disserta����es e teses da Associa����o Brasileira de Antropologia: uma an��lise cienciom��trica. 2001. 143 f. Disserta��ao (Mestrado) - Curso de Mestrado em Biblioteconomia e Ci��ncia da Informa����o, Pontif��cia Universidade Cat��lica de Campinas, Campinas, 2001.

Biblioteca digital de teses e disserta��oes: uma refer��ncia fundamental

OLIVEIRA, Raimundo Muniz de. Biblioteca digital de teses e disserta��oes: uma referencia fundamental. In: CINFORM ENCONTRO NACIONAL DE ENSINO E PESQUISA DA INFORMA��AO,HUMANISMO E DESENVOLVIMENTO CIENTIFICO E TECNOLOGICO,7.,2007,Salvador. Anais...Salvador:UFBA, 2007.Disponivel em:www.cinform.ufba.br>. Acesso em: 27 set. 2007. Acesso em: 27 set. 2010.

Bibblioteca Digital de Teses e Disserta����es: uma estrat��gia de preserva����o digital

CUNHA, Jacqueline de Ara��jo. Biblioteca Digital de Teses e Disserta����es: uma estrat��gia de preserva����o da mem��ria cient��fica. 2009. 141f. Disserta����o (Mestrado)- Programa de P��s-Gradua����o em Ci��ncia da Informa����o. Universidade Federal da Para��ba, Jo��o Pessoa, 2009.

Biblioteca Digital de Teses e Disserta����es: grau de utiliza����o pelos mestrandos do curso de Ci��ncia da Informa����o das Universidades P��blicas Brasileiras

A pesquisa aborda o uso das Tecnologias de Informa����o e Comunica����o, que vem revolucionando as atividades e ocasionando muitas mudan��as relacionadas ao acesso e uso de informa����es. O objetivo foi analisar o grau de utiliza����o do conhecimento cient��fico produzido pelos Programas de P��s-Gradua����o das Universidades P��blicas Brasileiras, atrav��s da BDTD, pelos mestrandos dos referidos programas. Nos procedimentos metodol��gicos realizados, procurou-se inicialmente analisar o amplo espectro da popula����o do corpus da pesquisa. Em raz��o da impossibilidade de trabalhar com os Programas de P��s-Gradua����o como um todo, optou-se por fazer um recorte, elegendo os cursos de P��s-Gradua����o em Ci��ncia da Informa����o, vez que estes representam o principal segmento social de interesse da pesquisa. Foi utilizado o m��todo de estudo de usu��rios, onde se optou por adotar o grupo, ���estudos orientados aos usu��rios���, que identifica as necessidades e comportamento de acesso e uso da informa����o. Para coletar os dados, elaborou-se um question��rio semi-estruturado com 25 quest��es, que versavam sobre o uso, dificuldades de acesso e recupera����o da informa����o, bem como a satisfa����o na utiliza����o dessa fonte informacional. Dentre os v��rios resultados obtidos, podemos destacar o fato de que a maioria dos mestrandos (71,8%) s�� teve contato com a BDTD somente no momento em que se encontrava cursando o mestrado e, somente 24,3%, tiveram contato durante a gradua����o. Estes resultados representam um problema, que pode afetar o bom desempenho do projeto BDTD, o qual consiste em disseminar e divulgar a produ����o cient��fica dos Programas de P��s-Gradua����o das Universidades P��blicas Brasileiras para a sua comunidade. Foi observado tamb��m, que os mestrandos oriundos do curso de Biblioteconomia tende a ter contato com a BDTD bem mais cedo do que mestrandos de outros cursos de gradua����o. A fim de minimizar o problema detectado, prop��e-se uma divulga����o mais eficaz na gradua����o atrav��s de dois procedimentos: Primeiro, o docente deve fazer uma divulga����o mais eficaz da BDTD junto aos discentes de todos os cursos de gradua����o; segundo: dever�� ser feita a divulga����o na m��dia eletr��nica, atrav��s da inser����o de ��cones da BDTD, nos portais dos Departamentos dos Cursos de Gradua����o das Universidades P��blicas Brasileiras. Acredita-se que com estes procedimentos seja poss��vel aperfei��oar o uso dessa fonte de informa����o cient��fica.

Bibliotecas digitais de teses e disserta����es brasileiras: paradigma do acesso livre �� informa����o cient��fica

A evolu����o da comunica����o cient��fica ao longo do tempo e o impacto causado pela A evolu����o da comunica����o cient��fica ao longo do tempo e o impacto causado pela A evolu����o da comunica����o cient��fica ao longo do tempo e o impacto causado pela se analisar as contribui����es da Biblioteca Digital de Teses e Disserta����es (BDTD)para a comunica����o cient��fica atual, destacando possibilidades emergentes e desafios a serem superados. Apresenta uma breve evolu����o da comunica����o cient��fica ao longo do tempo; discute os impactos causados pela Internet na comunica����o, disponibiliza����o e acessibilidade de informa����es t��cnico-cient��ficas; e caracteriza BDTD destacando os desafios a serem superados. Dentre eles est��o, a quest��o dos direitos autorais que ocasionam a baixa ades��o dos autores ao projeto piloto do IBICT para disponibilizar teses e disserta����es no meio eletr��nico. Para este desafio, s��o apontadas sugest��es.

Panorama brasileiro das bibliotecas digitais de teses e disserta����es

As bibliotecas de teses e disserta����es t��m um papel fundamental para o desenvolvimento cient��fico e cultural de um pa��s. Nesse sentido, buscou-se, de modo geral, analisar o panorama brasileiro das bibliotecas digitais de teses e disserta����es. Especificamente, objetivou-se caracterizar a sociedade da informa����o enquanto contexto das BDTD; caracterizar os v��rios tipos de bibliotecas surgidos a partir da inser����o das novas tecnologias de informa����o e comunica����o; identificar as diretrizes norteadoras da implanta����o de BDTD; e levantar as BDTD existentes no Brasil. Para tato, al��m de levantamento bibliogr��fico, realizou-se uma pesquisa nos sites de institui����es de ensino superior brasileiras que j�� disp��e de bibliotecas digitais de teses e disserta����es em funcionamento. A an��lise e interpreta����o destes dados nos permite considerar que no Brasil as BDTD encontram-se num est��gio embrion��rio, sendo relevante pesquisar a hist��rica implanta����o e configura����o desse novo modelo de biblioteca.

Anticorpos anti-trypanosoma cruzi como preditivos de infec����o por leishmania infantum

Leishmania infantum and Trypanosoma cruzi are trypanosomatids of medical importance and are, respectively, the etiologic agents of visceral leishmaniasis (VL) and Chagas disease (CD) in Brazil. People infected with L. infantum or T. cruzi may develop asymptomatically, enabling the transmission of pathogens through blood transfusion and / or organs. The assessment of the infection by T. cruzi is included among the tests performed for screening blood donors in Brazil, however, there is no availability of tests for Leishmania. Serological tests for T. cruzi are very sensitive, but not specific, and may have cross-reactions with other microorganisms. Thus, the aim of this study was to determine the prevalence of Leishmania infection in blood donors and assess whether the serological test for T. cruzi detect L. infantum. Among the 300 blood samples from donors, discarded in 2011, 61 were T. cruzi positive, 203 were from donors with other infections and 36 were from handbags with low blood volume, but without infection. We also assessed 144 samples from donors without infections and able to donate blood, totaling 444 subjects. DNA was extracted from blood samples of all to perform quantitative PCR (qPCR) to detect Leishmania DNA. The buffy coat obtained from all samples was grown in Schneider medium supplemented and NNN. All samples were evaluated for the presence of anti-Leishmania antibody. The serological results indicate a percentage of 22% of Leishmania infection in blood samples obtained from discarded bags. A total of 60% of samples positive in ELISA for T. cruzi were negative by IFI, used as confirmatory test, ie 60% false positive for Chagas. Among these samples false positive for Chagas, 72% were positive by ELISA for Leishmania characterizing the occurrence of cross reaction between serologic assays. Of the 300 cultures performed, 18 grew parasites that were typed by qPCR and specific isoenzymes, found the species Leishmania infantum crops. Among the 18 cultures, 4 were purged from scholarships for low volume and all negative serology blood bank, thus demonstrating that there is a real risk of Leishmania transmission via transfusion. It is concluded that in an area endemic for leishmaniasis in Brazil, serological diagnosis performed to detect infection by T. cruzi among blood donors can identify infection by L. infantum and although cause false positive for Chagas, this cross-reactivity reduces the risk of Leishmania infection via blood transfusion, since tests are not applied specific detection of the parasite. In this way, there remains the need to discuss the implementation of a specific serological screening test for Leishmania in endemic countries such as Brazil