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ID-NAT and serology are complementary in detecting HBV infection in first-time donors, but HBV-DNA is superior to HBsAg detection in repeat donors.

The aims of this study were to characterize human American tegumentary leishmaniasis, which includes cutaneous, mucocutaneous and mucosal leishmaniasis, in Northwest Argentina, to determine the prevalence of double infection with Trypanosoma cruzi and to identify the species of Leishmania in this area. Most of the 330 leishmaniasis patients presented cutaneous ulcers (96.1%), 2.4% mucocutaneous and 1.5% the mucosal form ('espundia'). The aetiological agents, determined by isoenzyme electrophoresis, were identified as Leishmania (Viannia) braziliensis in 16 out of 20 isolates and in the remaining 4 as Leishmania (Leishimania) amazonensis, the first ever-documented in Argentina. Sera analysed by ELISA and IFA using complex antigen from both T. cruzi and L. braziliensis showed a very high percentage of positives (66.3-78.2%). When antigens for specific diagnosis of Chagas' disease were used, 40.9% of the leishmaniasis patients were also found to be infected by T. cruzi. These results indicate that the strong immune response against T. cruzi gave no protection to Leishmania, in spite of the serological cross-reaction between these parasites. In addition, we showed that more than 40% of the patients would be misdiagnosed as chagasic if complex antigens, as epimastigotes or soluble fraction from epimastigotes, were used in IFA or ELISA. This is of paramount importance not only because patients' treatment would be associated to misdiagnosis but the fact that in many countries in Central and South America, a positive test for Chagas' disease means a rejection for those seeking employment.

Dodecanethiol-stabilized platinum nanoparticles of less than 3 nm have been synthesized for the first time through a modified two-phase liquid-liquid route. The H 2 PtCl 6 precursor was transferred from water to toluene using tetra-n-octylammonium bromide, followed by the addition of dodecanethiol. Results obtained by Raman spectroscopy, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) indicate a reaction between the platinum precursor and the thiol, resulting in a Pt(II)-stable complex that cannot be reduced by sodium borohydride. The Pt nanoparticles were obtained by the reduction of the platinum precursor before the introduction of dodecanethiol. The time interval at which the dodecanethiol was added to the reaction was used to control the size of the nanoparticles. The formation of dodecanethiol-stabilized Pt nanoparticles with fcc structure and average diameter of 1.7, 2.2 and 2.4 nm was confirmed by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), XANES, and EXAFS. All of the obtained nanoparticles were electrocatalytically active for methanol oxidation, and the differences in catalytic activity between different samples were related to the size and morphology of the nanoparticles.

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Studies were carried out on the recovery rate and cysticerci location in bovines experimentally infected with Taenia saginata eggs. Three calves of 6.5 months and one with 19 months of age were infected orally with 2 x 10(4) eggs of Taenia saginata. A fifth calf served as control. After 90 days of infection, the animals were slaughtered and organs and skeletal muscles were inspected using a slicing technique every 5 mm. From the four infected calves, 702 cysticerci were recovered, of which 570 (81.2%) were alive and 132 (18.8%) were degenerated. The recovery rate ranged from 0.01 to 1.43% with an average of 0.88%. The cysticerci presented the following anatomical distribution: hioideos muscles 02 (0.28%), kidneys 03 (0.43%), tongue 07 (1.00%), liver 12 (1.71%), lungs 15 (2.14%), diaphragm 18 (2.56%), mastication muscles 25 (3.56%), heart 49 (6.98%), anterior muscle 323 (46.00%) and posterior muscle 248 (35.33%).
Foi avaliada a taxa de recuperação e localização de cisticercos em bovinos experimentalmente infectados com ovos de Taenia saginata. Três bezerros de 6,5 meses e um adulto com 19 meses de idade foram infectados, por via oral, com 2 x 10(4) ovos de Taenia saginata. Um quinto bezerro serviu como testemunha. Após 90 dias da infecção, os animais foram abatidos. Fez-se inspeção, de todos os animais, por fatiamento de órgãos e musculatura esquelética, com intervalo entre os cortes de, no máximo, cinco milímetros. Dos quatros bezerros desafiados foram recuperados 702 cisticercos sendo 570 (81,20%) vivos e 132 (18,80%) degenerados. A taxa de recuperação foi de 0,01% a 1,43% com média de 0,88%. Os 702 cistos encontrados apresentaram a seguinte distribuição anatômica: músculos hióideos 02 (0,28%), rins 03 (0,43%), língua 07 (1,00%), fígado 12 (1,71%), pulmões 15 (2,14%), diafragma 18 (2,56%), músculos da mastigação 25 (3,56%), coração 49 (6,98%), musculatura dianteira 323 (46,00%) e musculatura traseira 248 (35,33%). Na infecção experimental os cistos encontraram-se distribuídos por toda a musculatura dos animais, não mostrando predileção pelos tecidos normalmente pesquisados pelo serviço de inspeção (língua, coração, diafragma, músculos mastigatórios). Os dados da inspeção de rotina pode não estimar a real incidência da cisticercose bovina. Os bovinos adultos são mais resistentes a infecção por ovos de Taenia saginata, apresentando menor número de cisticercos e com maior número de cistos calcificados

Novel silver nanoparticles/polyaniline composites were obtained through a two-phase water/toluene interfacial reaction. We show that by rigorously controlling the reaction time, different structures of the nanocomposites can be obtained, such as a thin sheet of polyaniline around the silver nanoparticles or a polymer mass with nanoparticles homogeneously embedded within it. Samples were characterized by FT-IR, UV-vis-NIR and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, TEM, and HRTEM. Conductivity and current-voltage characteristics of the nanocomposites were measured, and the results indicate that different properties result from the different structures in which the nanocomposites were formed.