Benchmarking the Current Codex Alimentarius International Estimated Short-Term Intake Equations and the Proposed New Equations.

The International Estimated Short-Term Intake IESTI equations are used during the establishment of Codex Maximum Residue Limits. A recent proposal to revise the equations sparked international debate regarding selection of residue inputs and the appropriate level of consumer protection. The 49th Codex Committee on Pesticide Residues meeting recommended benchmarking the IESTI equations against distributions of actual exposures.

Comprehensive Analysis of the Value of Single Versus Multiple Year (Season) Crop Residue Data for Establishment of Maximum Residue Levels (MRLs).

Disharmony currently exists in regulatory requirements regarding whether multiple seasons of field residue trials are necessary. This analysis used historical residue data to evaluate whether the year in which trials are conducted is a significant contributor to the overall variability in field residue data. It was concluded that residue behavior is highly variable in nature, regardless of the season, that variation of residue data compiled from multiple years is not statistically greater than data resulting from trials conducted within any one year, and that variation across years does not result in large systematic differences in residue values or resulting Maximum Residue Limits compared to trials conducted in any single year.

The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish (Danio rerio).

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants with elevated concentrations in waters that may also experience hypoxia. Previous research has shown interactions between hypoxia and some PAHs (fluoranthene, α-naphthoflavone) but no interaction with others (benzo[a]pyrene (BaP), β-naphthoflavone). Here we examine how hypoxia (7.

Hypoxia inhibits induction of aryl hydrocarbon receptor activity in topminnow hepatocarcinoma cells in an ARNT-dependent manner.

Hypoxic events often occur in waters contaminated with toxic chemicals, including agonists of the aryl hydrocarbon receptor (AhR). HIF-1alpha, the mediator of cellular responses to hypoxia, shares a dimerization partner (ARNT) with AhR and reciprocal crosstalk may occur. Studies addressing AhR/hypoxia crosstalk in mammalian cells have produced contradictory results regarding whether reciprocal crosstalk actually occurs between these pathways and the role ARNT plays in this interaction.

Development of the morpholino gene knockdown technique in Fundulus heteroclitus: a tool for studying molecular mechanisms in an established environmental model.

A significant challenge in environmental toxicology is that many genetic and genomic tools available in laboratory models are not developed for commonly used environmental models. The Atlantic killifish (Fundulus heteroclitus) is one of the most studied teleost environmental models, yet few genetic or genomic tools have been developed for use in this species. The advancement of genetic and evolutionary toxicology will require that many of the tools developed in laboratory models be transferred into species more applicable to environmental toxicology.

Gap junctional hemichannel-mediated ATP release and hearing controls in the inner ear.

Connexin gap junctions play an important role in hearing function, but the mechanism by which this contribution occurs is unknown. Connexins in the cochlea are expressed only in supporting cells; no connexin expression occurs in auditory sensory hair cells. A gap junctional channel is formed by two hemichannels.