Transfer RNA-mediated regulation of ribosome dynamics during protein synthesis.

Translocation of tRNAs through the ribosome during protein synthesis involves large-scale structural rearrangement of the ribosome and ribosome-bound tRNAs that is accompanied by extensive and dynamic remodeling of tRNA-ribosome interactions. How the rearrangement of individual tRNA-ribosome interactions influences tRNA movement during translocation, however, remains largely unknown. To address this question, we used single-molecule FRET to characterize the dynamics of ribosomal pretranslocation (PRE) complex analogs carrying either wild-type or systematically mutagenized tRNAs.

Influence of polarization and wavelength on two-photon excited luminescence of single gold nanospheres.

The Brownian rotation of a nearly spherical gold particle capped with ligands can be observed in the correlation profile of the intensity of the two-photon excited luminescence. Here we report on a multi-parameter study of the luminescence properties, including spectral and polarization analysis of the signal at the single particle level. First, the data confirm the role of the radiative de-excitation of the surface plasmons in the luminescence process.

Emerging roles of JAK-STAT signaling pathways in adipocytes.

Twenty years ago, adipocytes were largely considered to be inert energy-storage depots. We now know that fat cells are highly insulin-sensitive with significant endocrine functions. Alterations in adipocyte development or function can contribute to metabolic disease, in particular type 2 diabetes.

Genetic toxicology in the 21st century: reflections and future directions.

A symposium at the 40th anniversary of the Environmental Mutagen Society, held from October 24-28, 2009 in St. Louis, MO, surveyed the current status and future directions of genetic toxicology. This article summarizes the presentations and provides a perspective on the future.

[Management of aortic coarctation in adult].

Coarctation of the aorta accounts for 7% of congenital heart diseases. It is estimated that currently approximatively 10,000 adult patients have been operated on for coarctation in France. Bicuspid aortic valve occurs in more than 50% of patients.

Impaired spatial and binocular summation for motion direction discrimination in strabismic amblyopia.

Amblyopia is characterised by visual deficits in both spatial vision and motion perception. While the spatial deficits are thought to result from deficient processing at both low and higher level stages of visual processing, the deficits in motion perception appear to result primarily from deficits involving higher level processing. Specifically, it has been argued that the motion deficit in amblyopia occurs when local motion information is pooled spatially and that this process is abnormally susceptible to the presence of noise elements in the stimulus.

Activity profiles of 309 ToxCast™ chemicals evaluated across 292 biochemical targets.

Understanding the potential health risks posed by environmental chemicals is a significant challenge elevated by the large number of diverse chemicals with generally uncharacterized exposures, mechanisms, and toxicities. The present study is a performance evaluation and critical analysis of assay results for an array of 292 high-throughput cell-free assays aimed at preliminary toxicity evaluation of 320 environmental chemicals in EPA's ToxCast™ project (Phase I). The chemicals (309 unique, 11 replicates) were mainly precursors or the active agent of commercial pesticides, for which a wealth of in vivo toxicity data is available.

Stable periodicity and negative circuits in differential systems.

We provide a counter-example to a conjecture of René Thomas on the relationship between negative feedback circuits and stable periodicity in ordinary differential equation systems (Kaufman et al. in J Theor Biol 248:675-685, 2007). We also prove a weak version of this conjecture by using a theorem of Snoussi.

Monocular blindness in Bayelsa state of Nigeria.

Background: Monocular blindness has not received much attention in developing countries despite its numerous disadvantages. A monocularly blind person is at high risk of being bilaterally blind. The objective of this study was to determine the causes of monocular blindness in the study population and to suggest strategies for prevention.

The Vibrio cholerae virulence regulatory cascade controls glucose uptake through activation of TarA, a small regulatory RNA.

Vibrio cholerae causes the severe diarrhoeal disease cholera. A cascade of regulators controls expression of virulence determinants in V. cholerae at both transcriptional and post-transcriptional levels.

Causes of blindness and low vision in Bayelsa State, Nigeria: a clinic based study.

Background: No data are yet available on the causes of blindness and low vision in Bayelsa State of Nigeria.

Objective: The study is to provide baseline data on the causes of blindness and low vision in Yenagoa, Bayelsa State, Nigeria.

Methods: A prospective study was conducted among new consecutive patients presenting at the eye clinic of Niger Delta University Teaching Hospital.

Use of in vitro HTS-derived concentration-response data as biological descriptors improves the accuracy of QSAR models of in vivo toxicity.

Background: Quantitative high-throughput screening (qHTS) assays are increasingly being used to inform chemical hazard identification. Hundreds of chemicals have been tested in dozens of cell lines across extensive concentration ranges by the National Toxicology Program in collaboration with the National Institutes of Health Chemical Genomics Center.

Objectives: Our goal was to test a hypothesis that dose-response data points of the qHTS assays can serve as biological descriptors of assayed chemicals and, when combined with conventional chemical descriptors, improve the accuracy of quantitative structure-activity relationship (QSAR) models applied to prediction of in vivo toxicity end points.

Endocrine profiling and prioritization of environmental chemicals using ToxCast data.

Background: The prioritization of chemicals for toxicity testing is a primary goal of the U.S. Environmental Protection Agency (EPA) ToxCast™ program.

Ligand-induced anisotropy of the two-photon luminescence of spherical gold particles in solution unraveled at the single particle level.

Here we report on the visible luminescence properties of individual spherical gold particles in solution, obtained by two-photon excited fluorescence correlation spectroscopy and by an original dual Rayleigh-fluorescence method, correlating the Rayleigh scattering and the luminescence fluctuations of the same particle. The results demonstrate that the power needed to observe the two-photon excited visible luminescence depends on the illuminated particle and that the corresponding emission is anisotropic at low power. These observations combined with the evolution of the dynamics of the luminescence with respect to excitation power are interpreted by the presence of unique emissive surface states that are randomly switched off and on by the heat-induced movement of the molecular coating.

Advancing exposure characterization for chemical evaluation and risk assessment.

A new generation of scientific tools has emerged to rapidly measure signals from cells, tissues, and organisms following exposure to chemicals. High-visibility efforts to apply these tools for efficient toxicity testing raise important research questions in exposure science. As vast quantities of data from high-throughput screening (HTS) in vitro toxicity assays become available, this new toxicity information must be translated to assess potential risks to human health from environmental exposures.

OASIS-C: development, testing, and release. An overview for home healthcare clinicians, administrators, and policy makers.

The Outcomes and ASsessment Information Set Version C (OASIS-C) is the most comprehensive update to OASIS since its inception. This article describes the background and rationale for the changes, the testing process, an overview of the changes, and a description of the quality measures that will be generated from the use of OASIS-C.

Interest of β-blockers in patients with right ventricular systemic dysfunction.

Background: β-blockers improve the prognosis of patients with cardiac failure due to left ventricular systolic dysfunction. The aim of this study was to assess the efficacy of β-blockers in patients with dysfunctional systemic right ventricle.

Methods: Fourteen patients with systemic right ventricle following a Mustard or a Senning operation for the transposition of the great arteries, or congenitally corrected transposition were included in the study.

Mercury human exposure through fish consumption in a reservoir contaminated by a chlor-alkali plant: Babeni reservoir (Romania).

Purpose: Chlor-alkali plants are one of the most important point sources of mercury to aquatic environment. The problem of Hg contamination has been studied in a region, Rm Valcea (Romania), impacted by the wastewater discharge of a chlor-alkali plant. The purpose of the present study is to evaluate the current status of mercury pollution in the Babeni reservoir (Olt River) and the exposure of local population via fish consumption to mercury originating from the chlor-alkali plant.

In vitro screening of environmental chemicals for targeted testing prioritization: the ToxCast project.

Background: Chemical toxicity testing is being transformed by advances in biology and computer modeling, concerns over animal use, and the thousands of environmental chemicals lacking toxicity data. The U.S.

Ectopic expression of H-1 parvovirus NS1 protein induces alterations in actin filaments and cell death in human normal MRC-5 and transformed MRC-5 SV2 cells.

When grown in human cell lines, oncolytic H-1 parvovirus (H-1PV) replication preferentially occurs in transformed cells, which ultimately die upon infection. H-1PV-induced cytotoxicity is mainly due to P4 promoter-driven NS1 protein expression. Infection of untransformed cells generally does not induce deleterious effects because the P4 promoter is not activated.

Impact of environmental chemicals on key transcription regulators and correlation to toxicity end points within EPA's ToxCast program.

Exposure to environmental chemicals adds to the burden of disease in humans and wildlife to a degree that is difficult to estimate and, thus, mitigate. The ability to assess the impact of existing chemicals for which little to no toxicity data are available or to foresee such effects during early stages of chemical development and use, and before potential exposure occurs, is a pressing need. However, the capacity of the current toxicity evaluation approaches to meet this demand is limited by low throughput and high costs.

Real-world emission factors for antimony and other brake wear related trace elements: size-segregated values for light and heavy duty vehicles.

Hourly trace element measurements were performed in an urban street canyon and next to an interurban freeway in Switzerland during more than one month each, deploying a rotating drum impactor (RDI) and subsequent sample analysis by synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). Antimony and other brake wear associated elements were detected in three particle size ranges (2.5-10, 1-2.

Ethnic differences in the relationships of anthropometric measures to metabolic risk factors in Asian patients at risk of atherothrombosis: results from the REduction of Atherothrombosis for Continued Health (REACH) Registry.

The aim of the study is to examine the relationships between 4 anthropometric indices and metabolic risk factors (hypertension, atherogenic dyslipidemia, and glucose intolerance) in different Asian ethnic groups of patients at risk of atherothrombosis. We analyzed the baseline data of 11 017 Asian patients with established atherothrombotic cardiovascular diseases or at least 3 atherothrombotic risk factors. In East and South Asians, the graded relationships of body mass index (BMI) with the presence of at least 2 metabolic risk factors remained significant after adjustment for waist circumference (top vs bottom quartile--East Asians: odds ratio, 2.