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Full-Text Articles in Physical Sciences and Mathematics

Interim Report On Data And Methods For Assessment Of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin Risks To Aquatic Life And Associated Wildlife, Steven P. Bradbury, Philip M. Cook, Russell J. Erickson, Robert L. Spehar, Gerald T. Ankney Mar 1993

Interim Report On Data And Methods For Assessment Of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin Risks To Aquatic Life And Associated Wildlife, Steven P. Bradbury, Philip M. Cook, Russell J. Erickson, Robert L. Spehar, Gerald T. Ankney

Steven P. Bradbury

In April, 1991 the Administrator of the U.S. Environmental Protection Agency (EPA) announced that the Agency would conduct a scientific reassessment of the risk of 2,3,7,8-tetrachlorodibenzo-p-dioxin (hereafter referred to as TCDD), and similar chemicals, to human health and the environment. Since 1985, EPA has classified TCDD, which it considers the most potent known animal carcinogen, as a probable human carcinogen. Sources of TCDD in the environment were subsequently regulated on the basis of animal cancer rates extrapolated to doses associated with human exposures. Recently, consensus has developed that the toxic effects of TCDD appear to be mediated by its binding …


Toxicokinetics And Metabolism Of Aniline And 4-Chloroaniline In Medaka (Oryzias Latipes), Steven P. Bradbury, Julia M. Dady, Patrick N. Fitzsimmons, Michelle M. Voit, Dean E, Hammermeister, Russell J. Erickson Jan 1993

Toxicokinetics And Metabolism Of Aniline And 4-Chloroaniline In Medaka (Oryzias Latipes), Steven P. Bradbury, Julia M. Dady, Patrick N. Fitzsimmons, Michelle M. Voit, Dean E, Hammermeister, Russell J. Erickson

Steven P. Bradbury

The in vivo toxicokinetics and in vitro hepatic microsomal metabolism of (14C)aniline and (14C)4-chloroaniline in medaka (Oryzias latipes) were investigated to provide a basis upon which to interpret the toxicological responses of small aquarium fish to aniline derivatives. During static aqueous exposures of up to 320 min, parent equivalents failed to reach steady state and results from depuration studies clearly demonstrated biphasic elimination. Due to low elimination rates, 40 to 20% of absorbed aniline and 4-chloroaniline doses, respectively, remained within the fish through 330 min postexposure. Based on an analysis of excreted metabolites, N-acetylation was the dominant route of in …


A Non-Invasive Neurotoxicity Assay Using Larval Medaka, Steven P. Bradbury, Dave Featherstone, Charles D. Drewes, Joel R. Coats Jan 1993

A Non-Invasive Neurotoxicity Assay Using Larval Medaka, Steven P. Bradbury, Dave Featherstone, Charles D. Drewes, Joel R. Coats

Steven P. Bradbury

We present a method for non-invasive electrophysiological analysis of rapid escape responses in intact, freely behaving larval medaka (Oryzias latipes) before and after short-term exposure to environmental toxicants. Recordings are obtained as a larval medaka swims in a small chamber of water above pairs of recording electrodes etched onto a printed circuit board. When the chamber is briefly vibrated by a sinusoidal pulse from a speaker attached to the grid, a stereotyped Mauthner cell-initiated escape response is evoked. The following parameters were quantified from recordings: 1) Mauthner axon conduction velocity, 2) delay between Mauthner axon spike and motoneuron spike in …