Factors Associated with Physician Agreement on Verbal Autopsy of over 27000 Childhood Deaths in India

Introduction

Each year, more than 10 million children younger than five years of age die. The large majority of these deaths occur in the developing world. The verbal autopsy (VA) is a tool designed to ascertain cause of death in such settings. While VA has been validated against hospital diagnosed cause of death, there has been no research conducted to better understand the factors that may influence individual physicians in determining cause of death from VA.

Methodology/Principal Findings

This study uses data from over 27,000 neonatal and childhood deaths from The Million Death Study in which 6.3 million people in India were monitored for vital status between 1998 and 2003. The main outcome variable was physician agreement or disagreement of category of death and the variables were assessed for association using the kappa statistic, univariate and multivariate logistic regression using a conceptual hierarchical model, and a sensitivity and specificity analysis using the final VA category of mortality as the gold standard. The main variables found to be significantly associated with increased physician agreement included older ages and male gender of the deceased. When taking into account confounding factors in the multivariate analysis, we did not find consistent significant differences in physician agreement based on the death being in a rural or urban area, at home or in a health care facility, registered or not, or the respondent''s gender, religion, relationship to the deceased, or whether or not the respondent lived with the deceased.

Conclusions/Significance

Factors influencing physician agreement/disagreement to the greatest degree are the gender and age of the deceased; specifically, physicians tend to be less likely to agree on a common category of death in female children and in younger ages, particularly neonates. Additional training of physician reviewers and continued adaptation of the VA itself, with a focus on gender and age of the deceased, may be useful in increasing rates of physician agreement in these groups.     

Use of the novel technique of analytical ultracentrifugation with fluorescence detection system identifies a 77S monosomal translation complex

A fundamental problem in proteomics is the identification of protein complexes and their components. We have used analytical ultracentrifugation with a fluorescence detection system (AU-FDS) to precisely and rapidly identify translation complexes in the yeast Saccharomyces cerevisiae. Following a one-step affinity purification of either poly(A)-binding protein (PAB1) or the large ribosomal subunit protein RPL25A in conjunction with GFP-tagged yeast proteins/RNAs, we have detected a 77S translation complex that contains the 80S ribosome, mRNA, and components of the closed-loop structure, eIF4E, eIF4G, and PAB1. This 77S structure, not readily observed previously, is consistent with the monosomal translation complex. The 77S complex abundance decreased with translational defects and following the stress of glucose deprivation that causes translational stoppage. By quantitating the abundance of the 77S complex in response to different stress conditions that block translation initiation, we observed that the stress of glucose deprivation affected translation initiation primarily by operating through a pathway involving the mRNA cap binding protein eIF4E whereas amino acid deprivation, as previously known, acted through the 43S complex. High salt conditions (1M KCl) and robust heat shock acted at other steps. The presumed sites of translational blockage caused by these stresses coincided with the types of stress granules, if any, which are subsequently formed.     

Differential isotopic fractionation during Cr(VI) reduction by an aquifer-derived bacterium under aerobic versus denitrifying conditions

We studied Cr isotopic fractionation during Cr(VI) reduction by Pseudomonas stutzeri strain RCH2. Despite the fact that strain RCH2 reduces Cr(VI) cometabolically under both aerobic and denitrifying conditions and at similar specific rates, fractionation was markedly different under these two conditions (ε was ～2‰ aerobically and ～0.4‰ under denitrifying conditions).     

The role of selective breeding and biosecurity in the prevention of disease in penaeid shrimp aquaculture

About 3.5 million metric tons of farmed shrimp were produced globally in 2009 with an estimated value greater than USD$14.6 billion. Despite the economic importance of farmed shrimp, the global shrimp farming industry continues to be plagued by disease. There are a number of strategies a shrimp farmer can employ to mitigate crop loss from disease, including the use of Specific Pathogen Free (SPF), selectively bred shrimp and the adoption of on-farm biosecurity practices. Selective breeding for disease resistance began in the mid 1990s in response to outbreaks of Taura syndrome, caused by Taura syndrome virus (TSV), which devastated populations of farmed shrimp (Litopenaeus vannamei) throughout the Americas. Breeding programs designed to enhance TSV survival have generated valuable information about the quantitative genetics of disease resistance in shrimp and have produced shrimp families which exhibit high survival after TSV exposure. The commercial availability of these selected shrimp has benefitted the shrimp farming industry and TSV is no longer considered a major threat in many shrimp farming regions. Although selective breeding has been valuable in combating TSV, this approach has not been effective for other viral pathogens and selective breeding may not be the most effective strategy for the long-term viability of the industry. Cost-effective, on-farm biosecurity protocols can be more practical and less expensive than breeding programs designed to enhance disease resistance. Of particular importance is the use of SPF shrimp stocked in biosecure environments where physical barriers are in place to mitigate the introduction and spread of virulent pathogens.     

Learning by the parasitoid wasp, Aphidius ervi (Hymenoptera: Braconidae), alters individual fixed preferences for pea aphid color morphs

Learning, defined as changes in behavior that occur due to past experience, has been well documented for nearly 20 species of hymenopterous parasitoids. Few studies, however, have explored the influence of learning on population-level patterns of host use by parasitoids in field populations. Our study explores learning in the parasitoid Aphidius ervi Haliday that attacks pea aphids, Acyrthosiphon pisum (Harris). We used a sequence of laboratory experiments to investigate whether there is a learned component in the selection of red or green aphid color morphs. We then used the results of these experiments to parameterize a model that examines whether learned behaviors can explain the changes in the rates of parasitism observed in field populations in South-central Wisconsin, USA. In the first of two experiments, we measured the sequence of host choice by A. ervi on pea aphid color morphs and analyzed this sequence for patterns in biased host selection. Parasitoids exhibited an inherent preference for green aphid morphs, but this preference was malleable; initial encounters with red aphids led to a greater chance of subsequent orientation towards red aphids than predicted by chance. In a second experiment, we found no evidence that parasitoids specialize on red or green morphs; for the same parasitoids tested in trials separated by 2 h, color preference in the first trial did not predict color preference in the second, as would be expected if they differed in fixed preferences or exhibited long-term (> 2 h) learning. Using data from the two experiments, we parameterized a population dynamics model and found that learning of the magnitude observed in our experiments leads to biased parasitism towards the most common color morph. This bias is sufficient to explain changes in the ratio of aphid color morphs observed in field sites over multiple years. Our study suggests that for even relatively simple organisms, learned behaviors may be important for explaining the population dynamics of their hosts.     

Stomatal sensitivity to vapour pressure deficit of temperate and tropical evergreen rainforest trees of Australia

Although rainforests of eastern Australia grow in regions of high precipitation, there is a shift from a summer dry season in the temperate south to a winter dry season in the tropical north. Therefore, rainforest trees of eastern Australia provide an opportunity to investigate stomatal sensitivity of mesic trees to vapour pressure deficit (VPD) along a gradient in seasonality of precipitation. Eight rainforest canopy tree species were selected to cover the latitudinal range of rainforests in eastern Australia. Seedlings of these species were grown for a year in glasshouses under ambient conditions or at low VPD and water vapour exchange of leaves was measured during summer. Tropical species, which experience summer-dominant precipitation, showed higher stomatal sensitivities to VPD than temperate species, which experience winter-dominant precipitation. Growing plants under a low VPD increased stomatal sensitivity to increasing VPD in most species. The high stomatal sensitivity to VPD of the tropical species is consistent with the infrequent water stress experienced during their growing season and suggests a high susceptibility to water deficits. In contrast, temperate species may use other mechanisms to maintain photosynthesis under the relatively drier conditions of the temperate growing season.     

Transport of physiological nucleosides and anti-viral and anti-neoplastic nucleoside drugs by recombinant Escherichia coli nucleoside-H(+) cotransporter (NupC) produced in Xenopus laevis oocytes

The recently identified human and rodent plasma membrane proteins CNT1, CNT2 and CNT3 belong to a gene family (CNT) that also includes the bacterial nucleoside transport protein NupC. Heterologous expression in Xenopus oocytes has established that CNT1-3 correspond functionally to the three major concentrative nucleoside transport processes found in human and other mammalian cells (systems cit, cif and cib, respectively) and mediate Na(+) - linked uptake of both physiological nucleosides and anti-viral and anti-neoplastic nucleoside drugs. Here, one describes a complementary Xenopus oocyte transport study of Escherichia coli NupC using the plasmid vector pGEM-HE in which the coding region of NupC was flanked by 5'- and 3'-untranslated sequences from a Xenopus beta-globin gene. Recombinant NupC resembled human (h) and rat (r) CNT1 in nucleoside selectivity, including an ability to transport adenosine and the chemotherapeutic drugs 3'-azido-3'-deoxythymidine (AZT), 2',3'- dideoxycytidine (ddC) and 2'-deoxy-2',2'-difluorocytidine (gemcitabine), but also interacted with inosine and 2',3'- dideoxyinosine (ddl). Apparent affinities were higher than for hCNT1, with apparent K(m) values of 1.5-6.3 microM for adenosine, uridine and gemcitabine, and 112 and 130 microM, respectively, for AZT and ddC. Unlike the relatively low translocation capacity of hCNT1 and rCNT1 for adenosine, NupC exhibited broadly similar apparent V(max) values for adenosine, uridine and nucleoside drugs. NupC did not require Na(+) for activity and was H(+) - dependent. The kinetics of uridine transport measured as a function of external pH were consistent with an ordered transport model in which H(+) binds to the transporter first followed by the nucleoside. These experiments establish the NupC-pGEM-HE/oocyte system as a useful tool for characterization of NupC-mediated transport of physiological nucleosides and clinically relevant nucleoside therapeutic drugs.     

Protein folding as posttranslational regulation: evolution of a mechanism for controlled plasma membrane expression of a G protein-coupled receptor

Recent studies reveal that a number of G protein-coupled receptors (GPCRs) and other proteins are expressed inefficiently at the site normally associated with their biological action. In the case of some GPCRs, large amounts of receptor (perhaps more than half) may be destroyed without ever binding ligand or even arriving at the plasma membrane. For the human GnRH receptor (GnRHR), this apparent inefficiency has evolved under strong and convergent evolutionary pressure. The result is a human GnRHR molecule that is delicately balanced between either expression at the plasma membrane (PM) or retention/degradation in the endoplasmic reticulum, an effect mediated by engagement with the cellular quality control system. This balance appears to be the reason that the human receptor, but not the rat or mouse counterpart (which are more robustly routed to the PM), is highly susceptible to single-point mutations that result in disease. A single change in net charge is sufficient to tip the balance in favor of the endoplasmic reticulum and diminish GnRHR available at the PM. The apparent paradox that results from observing convergent pressure for evolution of a receptor that is both inefficiently produced and highly susceptible to mutational disease suggests that this approach must offer a strong advantage. This review focuses on the evolved mechanisms and considers that this is an underappreciated mechanism by which the cell controls functional levels of receptors and other proteins at the posttranslational level.