The CYD-TDV dengue vaccine was efficacious against VCD and severe VCD and led to fewer hospitalizations for VCD in five Latin American countries where dengue is endemic. (Funded by Sanofi Pasteur; ClinicalTrials.gov number, NCT01374516.).

The products of the Rhizobium leguminosarum hyp gene cluster are necessary for synthesis of a functional uptake [NiFe] hydrogenase system in symbiosis with pea plants, and at least for HypB and HypF, a role in hydrogenase-specific nickel metabolism has been postulated (L. Rey, J. Murillo, Y. Hernando, E. Hidalgo, E. Cabrera, J. Imperial, and T. Ruiz-Argiieso, Mol. Microbiol. 8:471-481, 1993). The R. leguminosarum hypB gene product has been overexpressed in Escherichia coli and purified by immobilized nickel chelate affinity chromatography in a single step. The purified recombinant HypB protein was able to bind 3.9 + 0.1 Ni2+ ions per HypB monomer in solution. Co2+, Cu2+, and Zn2+ ions competed with Ni2+ with increasing efficiency.Monospecific HypB antibodies were raised and used to show that HypB is synthesized in R. eguminosarum microaerobic vegetative cells and pea bacteroids but not in R. leguminosarum aerobic cells. HypB protein synthesized by R. kguminosarum microaerobic vegetative cells could also be isolated by immobilized nickel chelate affinity chromatography. A histidine-rich region at the amino terminus of the protein (23-HGHHHH DGHHDHDHDHDHHRGDHEHDDHHH-54) is proposed to play a role in nickel binding, both in solution and in chelated form.Rhizobium leguminosarum bv. viciae possesses an H2 uptake system that is able to oxidize H2 generated by the nitrogenase complex as a byproduct of the N2 reduction reaction (8,40). This system consists of an uptake [NiFe] hydrogenase and accessory proteins, and it is only expressed in the plant symbiotic state. The main features of the system have been studied by our laboratory in the Pisum-pea bacteroid symbiosis. The genetic determinants for the H2 uptake system are clustered in a 15-kb DNA region (hup region) in the symbiotic plasmid (21,22). This region has been sequenced, and 17 potential genes have been identified. The first six genes constitute the hydrogenase structural operon and include the genes hupS and hupL, encoding the hydrogenase polypeptides (13), and four additional genes, hupCDEF (14). A five-gene cluster containing hupGHIJK has been identified downstream the hydrogenase structural operon (38 Purification of the HypB protein by Ni(II)-NTA-agarose chromatography. The Ni(II)-nitrilotriacetic acid (NTA)-agarose matrix was obtained from Diagen (Dusseldorf, Germany), and the manufacturer's recommendations for its use (12) were followed, with minor modifications as follows.(i) Denaturing conditions. Frozen cells from a 100-ml induced culture were lysed in the presence of 6 M guanidineHCl (3.5 ml), and cell extracts were applied to an Ni(II)-NTAagarose column (2 by 0.8 cm). Proteins were stepwise eluted by means of buffers of decreasing pH, 8.0, 6.3, 5.9, and 4.5, all of which contained 8 M urea, at a flow rate of 0.5 ml min-1. Fractions (1 ml) were collected, and portions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Coomassie blue staining (18).(ii) Nondenaturing conditions. All the manipulations were carri...

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Rhizobium leguminosarum bv. viciae expresses an uptake hydrogenase in symbiosis with peas (Pisum sativum) but, unlike all other characterized hydrogenoxidizing bacteria, cannot express it in free-living conditions. The hydrogenase-specific transcriptional activator gene hoxA described in other species was shown to have been inactivated in R. leguminosarum by accumulation of frameshift and deletion mutations. Symbiotic transcription of hydrogenase structural genes hupSL originates from a ؊24͞؊12 type promoter (hupS p ). A regulatory region located in the ؊173 to ؊88 region was essential for promoter activity in R. leguminosarum. Activation of hupS p was observed in Klebsiella pneumoniae and Escherichia coli cells expressing the K. pneumoniae nitrogen fixation regulator NifA, and in E. coli cells expressing R. meliloti NifA. This activation required direct interaction of NifA with the essential ؊173 to ؊88 regulatory region. However, no sequences resembling known NifA-binding sites were found in or around this region. NifA-dependent activation was also observed in R. etli bean bacteroids. NifAdependent hupS p activity in heterologous hosts was also absolutely dependent on the RpoN -factor and on integration host factor. Proteins immunologically related to integration host factor were identified in R. leguminosarum. The data suggest that hupS p is structurally and functionally similar to nitrogen fixation promoters. The requirement to coordinate nitrogenase-dependent H 2 production and H 2 oxidation in nodules might be the reason for the loss of HoxA in R. leguminosarum and the concomitant NifA control of hup gene expression. This evolutionary acquired control would ensure regulated synthesis of uptake hydrogenase in the most common H 2 -rich environment for rhizobia, the legume nodule.

Background: Neonates admitted to neonatal intensive care units (NICU) are exposed to a wide variety of drugs, most without any data on safety and efficacy. Objective: To describe the drugs prescribed to different groups of neonates hospitalized in a NICU, and to analyze off-label use and harmful potential of drugs, in terms of the potential risks. Methods: This was a six-month retrospective cohort study of drug use in a NICU, with neonates who were inpatients for a period of over 24 hours, and using prescription data from electronic medical records. Drug information found in the package leaflets, in the British National Formulary for Children 2012-2013, and in the Thomson Micromedex database were compared. Drugs and excipients considered potentially harmful were evaluated according to the literature. Results: One hundred ninety-two neonates were included in the study, with a mean gestational age (GA) of 33.3 weeks (SD ± 4.3), 75.0 % were preterm, with an average of 18.8 days of hospitalization (SD ± 18.1), and a total of 3617 neonates-day. 3290 prescriptions were registered, on average 17.1 prescriptions/neonate (SD ± 17.9) and 8.8 drugs/neonate (SD ± 5.9). The number of prescriptions and drugs was higher in neonates with GA <31 weeks (p <0.05). Anti-infectives for systemic use, blood, alimentary tract and metabolism drug groups were more frequent, varying according to the GA. Neonates (99.5 %) were exposed to unlicensed drugs (UL) and off label use (OL), more frequently in GA <28 weeks (p <0.05). Most OL drugs used were indicated for newborns. 15 potentially harmful drugs were used in more than 70 % of the neonates, and most were OL; exposure to harmful excipients occurred in 91.6 % of the neonates, a percentage even higher when considering immature neonates. Conclusions: Immature neonates in a Brazilian NICU are exposed to a variety of OL, UL and potentially harmful drugs and excipients.

SummaryThe Tat (twin-arginine translocation) system mediates export of periplasmic proteins in folded conformation. Proteins transported via Tat contain a characteristic twin-arginine motif in their signal peptide. Genetic determinants ( tatABC genes) of the Tat system from Rhizobium leguminosarum bv. viciae were cloned and characterized, and a tatBC deletion mutant was constructed. The mutant lacked the ability for membrane targeting of hydrogenase, a known Tat substrate, and was impaired in hydrogenase activity. Interestingly, in the absence of a functional Tat system, only small, white nodules unable to fix nitrogen were induced in symbiosis with pea plants. Analysis of nodule structure and location of green fluorescent protein (GFP)-tagged bacteria within nodules indicated that the symbiotic process was blocked in the tat mutant at a stage previous to bacteria release into cortical cells. The R. leguminosarum Tat-deficient mutant lacked a functional cytochrome bc 1 complex. This was consistent with the fact that R. leguminosarum Rieske protein, a key component of the symbiosis-essential cytochrome bc 1 complex, contained a typical twin-arginine signal peptide. However, comparative analyses of nodule structure indicated that nodule development in the tat mutant was arrested at an earlier step than in a cytochrome bc 1 mutant. These data indicate that the Tat pathway is also critical for proteins relevant to the initial stages of the symbiotic process.

BOOK REVIEW*REY, Luís -Dicionário de termos técnicos de medicina e saúde. 2ª edição. Rio de Janeiro, Guanabara Koogan, 2003. 950p. ilus. ISBN 85-277-0848-5 O objetivo deste livro é ser um dicionário informativo, de manejo fácil e prático, destinado a médicos, biomédicos, profissionais de saúde pública, dentistas, farmacêuticos, laboratoristas, biólogos etc., bem como a estudantes, mestrandos, doutorandos e professores ou pesquisadores das áreas médicas e afins. É um livro técnico, sem ser obra especializada em campos restritos. Como tal, ele preenche um vazio em nossa literatura científica, pois as publicações existentes são antigas ou traduções de dicionários escritos em outros idiomas e preparados para usuários de países onde os riscos para a saúde, as patologias, os problemas de saúde pública ou os modos de abordá-los são diferentes dos nossos. Grande ênfase foi posta nas bases científicas da prática médica moderna, que incluem, além da morfologia, fisiologia e patologia, setores especiais como bioquímica e biologia molecular, genética, ecologia, epidemiologia, farmacodinâmica e imageamento.

Pneumococcal carriage rate was higher in healthy children than in children with pneumonia. Penicillin and cotrimoxazole resistance rates were high, especially among those attending day-care centers.