Structure and Function of Cyanobacterial DHDPS and DHDPR.

Lysine biosynthesis in bacteria and plants commences with a condensation reaction catalysed by dihydrodipicolinate synthase (DHDPS) followed by a reduction reaction catalysed by dihydrodipicolinate reductase (DHDPR). Interestingly, both DHDPS and DHDPR exist as different oligomeric forms in bacteria and plants. DHDPS is primarily a homotetramer in all species, but the architecture of the tetramer differs across kingdoms. DHDPR also exists as a tetramer in bacteria, but has recently been reported to be dimeric in plants. This study aimed to characterise for the first time the structure and function of DHDPS and DHDPR from cyanobacteria, which is an evolutionary important phylum that evolved at the divergence point between bacteria and plants. We cloned, expressed and purified DHDPS and DHDPR from the cyanobacterium Anabaena variabilis. The recombinant enzymes were shown to be folded by circular dichroism spectroscopy, enzymatically active employing the quantitative DHDPS-DHDPR coupled assay, and form tetramers in solution using analytical ultracentrifugation. Crystal structures of DHDPS and DHDPR from A. variabilis were determined at 1.92 Å and 2.83 Å, respectively, and show that both enzymes adopt the canonical bacterial tetrameric architecture. These studies indicate that the quaternary structure of bacterial and plant DHDPS and DHDPR diverged after cyanobacteria evolved.

Comparison of pregnancy characteristics and outcomes between HIV-infected and HIV-non-infected women in Brazil.

The aim of this study is to evaluate the characteristics of pregnant women whether they are HIV infected or not and their prenatal care. It is a cross-sectional study. HIV-infected women were derived from a cohort study of all HIV-infected pregnant women followed from 1995 to 2005, at the Instituto de Puericultura e Pediatria Martagão Gesteira - Rio de Janeiro. HIV-non-infected women were derived from a random sample of all pregnant women who gave birth at Rio de Janeiro municipality between 1999 and 2001. All relevant sociodemographic, clinical, and pregnancy outcomes data were retrieved from both studies. To evaluate the prenatal care, we calculated the Kotelchuck Modified Index (KMI). The index is based on the months of initiation of prenatal care and the proportion of visits observed in each trimester, according to gestational age at birth. Comparisons were performed using Student t- and chi-square tests. Variables with p-value < 0.25 were included in an unconditional logistic regression model. There were 713 HIV-infected women and 2145 HIV-non-infected women. Variables independently associated with HIV status were: inadequate KMI (OR=4.08, 95% CI=3.17-5.24); lower educational level (OR=1.32, 95% CI=1.04-1.68); does not live with a partner (OR=3.54, 95% CI=2.66-4.64); lower family income (OR=4.71, 95% CI=3.62-6.14); tobacco use (OR=2.17, 95% CI=1.63-2.88); and hypertension (OR=1.47, 95% CI=1.01-2.17). Prematurity was not independently associated with HIV status. Although in Brazil, the HIV care is free of charge, pregnant women are still having difficulty to reach the specialized care. Better access to care must be offered to this population and studies of prematurity in the HIV-infected women must evaluate their prenatal care.

[Analysis of adequacy and effectiveness in the use of tocolytics in preterm labor]. / Anlise da adequação e da efetividade do uso de tocolíticos no trabalho de parto prematuro.

The objective of this study was to assess quality of care for premature labor at public maternity facilities in Rio de Janeiro, Brazil, using referents, indicators, and standards of care derived from scientific evidence. The standard utilized in the process analysis for use of betamimetic tocolytics was 100%, considering the related referents. For outcome analysis, the standard applied was the occurrence of premature delivery in 11% of patients within 24 h and in 24% of patients (referent) within 48 h of hospital admission. Use of tocolytics was observed in 18.7% of patients admitted in premature labor. At gestational age from 28 weeks to 33 weeks and 6 days, especially critical for neonatal survival, tocolytics were used in 32.6% of patients. Premature birth occurred in 59% of patients within 24 h and in 64% within 48 h. These outcomes were consistent with the low rate of utilization of tocolytics. Effectiveness of care for preterm labor measured by rate of premature birth was low. Results of the corresponding process and outcomes analysis were consistent.

Estimating the effectiveness of perinatal care technologies by expert opinion.

The majority of technologies in use in perinatal care were organized into 45 technological functions. Forty-six experts from 19 different regions of Brazil and other Latin American countries then selected a "basic package" (BP) of 15 technological functions. Considering the 12 main causes of perinatal mortality in Brazil, the experts estimated the number of preventable deaths, assuming universal coverage by the BP and the additional reductions that could be obtained by gradually adding other technological functions to the BP. A simulation was performed for the 26 states of Brazil to identify regional priorities for the diffusion of technological functions. For most regions, the BP appears to be the most effective intervention, with the potential of reducing perinatal mortality by 33%, followed by "coordination of services and referral of pregnant women" (14%), and "treatment of respiratory conditions" (11.8%).