Screening for White Spot Syndrome Virus (WSSV) in pink shrimp (Penaeus paulensis) from Rocha Lagoon, Uruguay.

Penaeus paulensis (pink shrimp) is an important resource for small-scale fisheries in the brackish coastal lagoons of Uruguay. No viral diseases have been detected in shrimp populations in the Uruguayan territory. The presence of viral pathogens, such as White Spot Syndrome Virus (WSSV) and Infectious Hypodermal Haematopoietic Necrosis Virus (IHHNV) in wild shrimp populations has been previously reported in Brazil and Argentina. We investigated the presence of WSSV in wild populations of penaeid shrimp from Rocha Lagoon, Uruguay. We sampled 70 specimens of juvenile P. paulensis and assessed the presence of these viral pathogens using nested PCR and histology. Gill tissue from the 70 samples was divided into 14 pools of 5 individuals for DNA extraction and PCR analysis. We also retested each pooled sample individually. The nested PCR procedure described in the WOAH aquatic animal manual was used. A subset of 20 individual specimens were also processed using standard histological techniques. The results showed that WSSV was not detected in the pooled or individually tested samples. We found no evidence of the presence of the viral genome or gill lesions in the samples analysed. This indicates that the fishery is still likely to be free of WSSV infection. The procedures and information generated can be used as a baseline study for future implementation of surveillance programmes in the country.

A Study on Truncated Newton Methods for Linear Classification.

Truncated Newton (TN) methods have been a useful technique for large-scale optimization. Instead of obtaining the full Newton direction, a truncated method approximately solves the Newton equation with an inner conjugate gradient (CG) procedure (TNCG for the whole method). These methods have been employed to efficiently solve linear classification problems. However, even in this deeply studied field, various theoretical and numerical aspects were not completely explored. The first contribution of this work is to comprehensively study the global and local convergence when TNCG is applied to linear classification. Because of the lack of twice differentiability under some losses, many past works cannot be applied here. We prove various missing pieces of theory from scratch and clarify many proper references. The second contribution is to study the termination of the CG method. For the first time when TNCG is applied to linear classification, we show that the inner stopping condition strongly affects the convergence speed. We propose using a quadratic stopping criterion to achieve both robustness and efficiency. The third contribution is that of combining the study on inner stopping criteria with that of preconditioning. We discuss how convergence theory is affected by preconditioning and finally propose an effective preconditioned TNCG.

Mass mortality associated with a frog virus 3-like Ranavirus infection in farmed tadpoles Rana catesbeiana from Brazil.

Ranaviruses (Iridoviridae) are increasingly associated with mortality events in amphibians, fish, and reptiles. They have been recently associated with mass mortality events in Brazilian farmed tadpoles of the American bullfrog Rana catesbeiana Shaw, 1802. The objectives of the present study were to further characterize the virus isolated from sick R. catesbeiana tadpoles and confirm the etiology in these outbreaks. Sick tadpoles were collected in 3 farms located in Goiás State, Brazil, from 2003 to 2005 and processed for virus isolation and characterization, microbiology, histopathology, and parasitology. The phylogenetic relationships of Rana catesbeiana ranavirus (RCV-BR) with other genus members was investigated by PCR with primers specific for the major capsid protein gene (MCP) and the RNA polymerase DNA-dependent gene (Pol II). Sequence analysis and multiple alignments for MCP products showed >99% amino acid identity with other ranaviruses, while Pol II products showed 100% identity. Further diagnostics of the pathology including histology and transmission electron microscopy confirmed the viral etiology of these mass deaths. As far as we know, this is the first report of a ranaviral infection affecting aquatic organisms in Brazil. Additionally, our results suggest that American bullfrogs may have served as a vector of transmission of this virus, which highlights the potential threat of amphibian translocation in the world distribution of pathogens.

Modeling cancer drug response through drug-specific informative genes.

Recent advances in pharmacogenomics have generated a wealth of data of different types whose analysis have helped in the identification of signatures of different cellular sensitivity/resistance responses to hundreds of chemical compounds. Among the different data types, gene expression has proven to be the more successful for the inference of drug response in cancer cell lines. Although effective, the whole transcriptome can introduce noise in the predictive models, since specific mechanisms are required for different drugs and these realistically involve only part of the proteins encoded in the genome. We analyzed the pharmacogenomics data of 961 cell lines tested with 265 anti-cancer drugs and developed different machine learning approaches for dissecting the genome systematically and predict drug responses using both drug-unspecific and drug-specific genes. These methodologies reach better response predictions for the vast majority of the screened drugs using tens to few hundreds genes specific to each drug instead of the whole genome, thus allowing a better understanding and interpretation of drug-specific response mechanisms which are not necessarily restricted to the drug known targets.

A novel dense CO(2) supercritical fluid technology for the development of microparticulate delivery systems containing ketoprofen.

VarioSol® is an innovative, solvent-free technology able to produce microparticles exploiting near-critical CO(2) properties as spraying and cooling agent. The aim of the present work was to evaluate the feasibility to produce in a single processing step by VarioSol® technology, oral ketoprofen-loaded microparticles with gastro-protective properties. The obtained products were powders composed of regular in shape and small in diameter microparticles, characterized by high drug content (40%) and good flow properties. Microparticles were composed by anionic lipids scarcely soluble at acidic pH, blended with gastro-resistant polymers of the methacrylate type. In vitro drug release results indicated that the drug was rapidly delivered from the microparticulate systems in phosphate buffer at pH 6.8, while in acidic medium, the microparticles were able to retard the drug release process but without reaching complete gastro-resistance. However, the results obtained in this study, although non optimal, are not far from the specifications required for gastro-resistant release products (i.e., no more than 10% drug released after 1h at pH 1.0) according to EMA guidelines and represent a good starting point for future formulation development.