Comparative insecticidal power of three pyrethroids on netting

Adult mosquitoes, Anopheles gambiae Giles and Culex quinquefasciatus Say (Diptera: Culicidae), were exposed for 3 min to replicate samples of polyester netting cut from replicate bednets treated with pyrethroid insecticide formulations at the recommended concentration (alphacypermethrin SC at 40mg ai/m2; cyfluthrin EW at 50 mg ai/m2; deltamethrin WT at 25 mg ai/m2), or treated with only a quarter of those dosages. After 4 months domestic use of the bednets in Malawi, chemical assays showed that pyrethroid deposits on the netting were somewhat less than the target concentrations. Comparing the pyrethroid bioassay results with Anopheles at both treatment concentrations, deltamethrin gave significantly higher mortality (99.7-100%) than the other compounds (alphacypermethrin 94-96%, cyfluthrin 80-89%). Culex bioassay mortality was lower (alphacypermethrin 56-74%; cyfluthrin 63-65%; deltamethrin 50-81 %) and results with the three pyrethroid insecticides at their recommended doses did not differ significantly.     

Bi- and tetraflavonoids from Aristolochia ridicula

From stems of Aristolochia ridicula, two biflavones, four unusual chalcone-flavone dimers and one tetraflavonoid were isolated. The structures of the seven compounds were elucidated by spectroscopic methods.     

Modelling T-cell-mediated suppression dependent on interactions in multicellular conjugates

Tolerance to peripheral body antigens involves multiple mechanisms, namely T-cell-mediated suppression of potentially autoimmune cells. Recent in vivo and in vitro evidence indicates that regulatory T cells suppress the response of effector T cells by a mechanism that requires the simultaneous conjugation of regulatory and effector T cells with the same antigen-presenting cell (APC). Despite this strong requirement, it is not yet clear what happens while both cells are conjugated. Several hypotheses are discussed in the literature. Suppression may result from simple competition of regulatory and effector cells for activation resources on the APC; regulatory T cells may deliver an inhibitory signal to effector T cells in the same conjugate; or effector T cells may acquire the regulatory phenotype during their interaction with regulatory T cells. The present article tries to further our understanding of T-cell-mediated suppression, and to narrow-down the number of candidate mechanisms. We propose the first general formalism describing the formation of multicellular conjugates of T cells and APCs. Using this formalism we derive three particular models, representing alternative mechanisms of T-cell-mediated suppression. For each model, we make phase plane and bifurcation analysis, and identify their pros and cons in terms of the relationship with the large body of experimental observations on T-cell-mediated suppression. We argue that accounting for the quantitative details of adoptive transfers of tolerance requires models with bistable regimes in which either regulatory cells or effectors cells dominate the steady state. From this analysis, we conclude that the most plausible mechanism of T-cell-mediated suppression requires that regulatory T cells actively inhibit the growth of effector T cells, and that the maintenance of the population of regulatory T cells is dependent on the effector T cells. The regulatory T cell population may depend on a growth factor produced by effector T cells and/or on a continuous differentiation of effector cells to the regulatory phenotype.     

In vitro regeneration from leaf explants of Neoregelia cruenta (R. Graham) L.B. Smith,an endemic bromeliad from Eastern Brazil

An efficient plant regeneration system was developed for the induction of direct shoot formation from leaves derived from seedlings of Neoregelia cruenta, an endemic Bromeliaceae of Eastern Brazil. Shoot differentiation occurred directly from the leaf bases. In vitro responses were influenced by seedling age and growth regulator combinations. Highest regeneration rates were obtained from explants excised from 7-week-old seedlings cultured in the presence of 22 μM BA and 2.5 μM NAA. Shoot conversion to whole plants was most effective in shoots formed in response to 4.4 or 8.8 μM BA combined with 2.5 μM NAA. This revised version was published online in June 2006 with corrections to the Cover Date.     

Terlipressin versus Norepinephrine in the Treatment of Hepatorenal Syndrome: A Systematic Review and Meta-Analysis

Background

Hepatorenal syndrome (HRS) is a severe and progressive functional renal failure occurring in patients with cirrhosis and ascites. Terlipressin is recognized as an effective treatment of HRS, but it is expensive and not widely available. Norepinephrine could be an effective alternative. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of norepinephrine compared to terlipressin in the management of HRS.

Methods

We searched the Medline, Embase, Scopus, CENTRAL, Lilacs and Scielo databases for randomized trials of norepinephrine and terlipressin in the treatment of HRS up to January 2014. Two reviewers collected data and assessed the outcomes and risk of bias. The primary outcome was the reversal of HRS. Secondary outcomes were mortality, recurrence of HRS and adverse events.

Results

Four studies comprising 154 patients were included. All trials were considered to be at overall high risk of bias. There was no difference in the reversal of HRS (RR = 0.97, 95% CI = 0.76 to 1.23), mortality at 30 days (RR = 0.89, 95% CI = 0.68 to 1.17) and recurrence of HRS (RR = 0.72; 95% CI = 0.36 to 1.45) between norepinephrine and terlipressin. Adverse events were less common with norepinephrine (RR = 0.36, 95% CI = 0.15 to 0.83).

Conclusions

Norepinephrine seems to be an attractive alternative to terlipressin in the treatment of HRS and is associated with less adverse events. However, these findings are based on data extracted from only four small studies.     

Identification of species by multiplex analysis of variable-length sequences

The quest for a universal and efficient method of identifying species has been a longstanding challenge in biology. Here, we show that accurate identification of species in all domains of life can be accomplished by multiplex analysis of variable-length sequences containing multiple insertion/deletion variants. The new method, called SPInDel, is able to discriminate 93.3% of eukaryotic species from 18 taxonomic groups. We also demonstrate that the identification of prokaryotic and viral species with numeric profiles of fragment lengths is generally straightforward. A computational platform is presented to facilitate the planning of projects and includes a large data set with nearly 1800 numeric profiles for species in all domains of life (1556 for eukaryotes, 105 for prokaryotes and 130 for viruses). Finally, a SPInDel profiling kit for discrimination of 10 mammalian species was successfully validated on highly processed food products with species mixtures and proved to be easily adaptable to multiple screening procedures routinely used in molecular biology laboratories. These results suggest that SPInDel is a reliable and cost-effective method for broad-spectrum species identification that is appropriate for use in suboptimal samples and is amenable to different high-throughput genotyping platforms without the need for DNA sequencing.     

Physical mapping of rDNA genes corroborates allopolyploid origin in apomictic Brachiaria brizantha

Brachiaria (Trin.) Griseb belongs to the family Poaceae, and within the genus, apomixis or sexuality is present in different accessions of the same species. The majority of Brachiaria species are polyploid and apomictic, making strategies for crop improvement by breeding very intricate. In spite of the high frequency of apomictic polyploids, the relationship of polyploidy and hybridization with apomixis in Brachiaria is still unclear. Further analysis requires detailed knowledge regarding the genomic composition of the polyploids. The present work introduces the use of fluorescent in situ hybridization (FISH) into cytogenetic analysis of Brachiaria. Physical mapping of heterologous rDNA sequences, associated with conventional karyotyping of the B. brizantha diploid sexual (BRA 002747) and the tetraploid apomictic (BRA000591) accessions, provided evidence of the latter being of allopolyploid origin. Based on our results and on previous knowledge on apomixis in B. brizantha, we suggest that the origin of apomixis was probably a consequence of hybridization.     

Gall-inducing insect species richness as indicators of forest age and health

The changes in the plant community that occur during the process of succession affect the availability of resources for the community of herbivores. In this study, the richness of galling insects was evaluated in restored stands of Amazonian tropical rain forest of several ages (0-21 yr), as well as in areas of primary forest in Brazil. The richness of gallers increased with the age of the restored stands. Fifty-eight percent of the variation in the richness of galling insects was explained by forest stand age, but an increase in richness was observed at intermediate stages of succession. The greatest similarity among groups was found between the initial successional stages and intermediate ones. The results indicate a recovery of both host plants and insect community and that succession directly affects the richness and composition of these herbivores.     

IgG and IgM western blot assay for diagnosis of congenital toxoplasmosis

The aim of this study was to evaluate the utility of western blot (WB) analysis as a diagnostic tool for congenital toxoplasmosis in 215 newborn infants. The children were submitted to clinical examinations to assess macular, neurological and hearing signals. The WB results obtained were compared to the persistence of IgG antibodies at the end of 12 months, which is regarded as the "gold standard" diagnosis of congenital toxoplasmosis. Association between the WB results and the clinical signs presented by the infants was also assessed. Of the 215 children, 177 had a confirmed congenital toxoplasmosis diagnosis and 38 were uninfected. IgG-WB showed a sensitivity of 73.5% and a specificity of 97.4%. IgM-WB showed a sensitivity of 54.8% and a specificity of 94.7%. The IgG-WB and IgM-WB combination increased the sensitivity to 86.5%. The IgM-WB-positive children had a 1.4-fold greater risk of presenting active macular lesions than did those that were IgM-WB-negative. This study showed that the WB assay is a useful tool to confirm a diagnosis of congenital toxoplasmosis and that the IgM-WB-positive results can indicate active macular lesions in newborn infants.