The use and acceptance of Other Scientifically Relevant Information (OSRI) in the U.S. Environmental Protection Agency (EPA) Endocrine Disruptor Screening Program.

The U.S. Environmental Protection Agency (EPA) Endocrine Disruptor Screening Program (EDSP) currently relies on an initial screening battery (Tier 1) consisting of five in vitro and six in vivo assays to evaluate a chemical's potential to interact with the endocrine system.

Lessons learned, challenges, and opportunities: the U.S. Endocrine Disruptor Screening Program.

In 1996, the U.S. Congress passed the Food Quality Protection Act and amended the Safe Drinking Water Act (SDWA) requiring the U.

Animal use and lessons learned in the U.S. High Production Volume Chemicals Challenge Program.

Background: Launched by the U.S. Environmental Protection Agency (EPA) in 1998, the High Production Volume (HPV) Challenge Program was developed to address the perceived gap in basic hazard information for the 2,800 chemicals produced or imported into the United States in quantities of ≥ 1 million pounds per year.

Application of an integrated testing strategy to the U.S. EPA endocrine disruptor screening program.

New approaches to generating and evaluating toxicity data for chemicals are needed to cope with the ever-increasing demands of new programs. One such approach involves the use of an integrated testing and evaluation strategy based on the specific properties and activities of a chemical. Such an integrated strategy, whether applied to existing or future programs, can promote efficient use of resources and save animals.

Expression of the winged helix/forkhead gene, foxn4, during zebrafish development.

The winged-helix/forkhead transcription factor gene, foxn4, is expressed in the nervous system of developing and adult zebrafish. Prominent expression sites include the olfactory placode, the basal layer of the olfactory epithelium, the neuroepithelium of the developing retina, the germinal zone of the differentiated eye, regions of motoneuron development in the neural tube and periventricular regions of the brain. The adult thymus is the only major site of foxn4 expression outside of the nervous system.

T cells and the thymus in developing zebrafish.

The expression of genes encoding T cell receptor (TCR) alpha was used to follow the development of the thymus and to analyze the distribution of T cells in zebrafish. In the thymus, expression was first detected, by in situ hybridization, at four days post fertilization. In RNA extracted from whole fish, TCRalpha transcripts were also detected at four days and reached adult levels at three weeks.