Detection and Quantification of Leptospira interrogans in Hamster and Rat Kidney Samples: Immunofluorescent Imprints versus Real-time PCR

A major limitation in the clinical management and experimental research of leptospirosis is the poor performance of the available methods for the direct detection of leptospires. In this study, we compared real-time PCR (qPCR), targeting the lipL32 gene, with the immunofluorescent imprint method (IM) for the detection and quantification of leptospires in kidney samples from the rat and hamster experimental models of leptospirosis. Using a virulent strain of Leptospira interrogans serovar Copenhageni, a chronic infection was established in the rat model, which were euthanized 28 days post-infection, while the hamster model simulated an acute infection and the hamsters were euthanized eight days after inoculation. Leptospires in the kidney samples were detected using culture isolation, qPCR and the IM, and quantified using qPCR and the IM. In both the acute and chronic infection models, the correlation between quantification by qPCR and the IM was found to be positive and statistically significant (P<0.05). Therefore, this study demonstrates that the IM is a viable alternative for not only the detection but also the quantification of leptospires, particularly when the use of qPCR is not feasible

Development of a Methodology for Structural and Mechanical Characterization of Extended Sheets Made from Stainless Steels

Extended sheets are produced by a pressure cutting process to transform common sheets in expanded metal. These sheets are usually made of carbon steel, but due to their corrosion susceptible, studies have been developed with the aim to evaluate the viability of replacing these common steels by stainless steels. This study proposed an experimental method to characterize structural and mechanically samples of stainless steel extended sheets (410D, 444A, 439 and 304A) and a 1010 carbon steel sheet thicker than the others. This study has a practical importance because nowadays there are not standardized procedures to do this kind of evaluation. The obtained results showed that the methodology was effective for the proposed objective and that the expanded sheets made of stainless steels have a better performance in terms of mechanical strength compared to the 1010 steel sheet