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R J Norstrom

Publications and source records attributed to R J Norstrom.

58 records · Page 4Linked to original sources
PubMedDate not supplied

Immunoquantitation of cytochromes P450 1A and P450 2B and comparison with chlorinated hydrocarbon levels in archived polar bear liver samples.

The present study examined the utility of an immunoblot method for quantitation of cytochrome P450 isozymes in archived liver samples as a bioassay of exposure to halogenated hydrocarbons. Hepatic microsomes were prepared from 44 archived polar bear (Ursus maritimus) liver homogenates that had been stored at approximately -40 degrees C for 9-10 years and analyzed on blots probed with antibodies to rat cytochromes P450 1A1 and P450 2B1. The results revealed a positive correlation between cytochrome P450 1A and total polychlorinated biphenyl (PCB) levels in the archived liver samples, suggesting that cytochrome P450 1A was induced in polar bears by environmental exposure to PCBs.

Animals↗
PubMedDate not supplied

Toxicological response and its reversibility in rats fed Lake Ontario or Pacific coho salmon for 13 weeks.

Lake Ontario coho salmon were known to contain a mixture of chemical contaminants. A previous study demonstrated that rats fed the Lake Ontario fish-supplemented diet for 28 days exhibited mild biochemical and histological changes. The purpose of the present study was to determine the effects due to a longer term of exposure and the reversibility of these effects. Growth rate and food consumption were not affected by feeding the animals with Lake Ontario or Pacific fish-supplemented diets for 13 weeks. No deaths were observed. Decreased spleen weights were observed in groups of males fed 1.45%, 5.8% Lake Ontario and 2.9% Pacific diet. After a 13 week recovery the spleen weights returned to normal. Decreased serum potassium was observed in male rats fed 2.9% Lake Ontario diet, and all levels of Pacific diet for 13 weeks, and was not evident following maintenance on normal diet. Serum glucose was not affected by the 13-week period of treatment, however; a reduction in this parameter occurred in male rats fed the two highest doses of Lake Ontario diet and all doses of Pacific diet following the 13-week recovery period. Minor hematological changes occurred only in the male rats fed either Lake Ontario or Pacific diet following a 13 week recovery period and included reduced marrow myeloid cells and myeloid/erythroid ratio. Hepatic microsomal ethoxyresorufin deethylase activity was significantly increased in rats ingesting Lake Ontario diet. Mild histological changes occurred in the liver and thyroid of the treated males, and in the liver and kidney of the treated females. These changes were attributed to the chemical residues and/or the fish diet. Data presented here indicated that the Lake Ontario fish-supplemented diet can cause mild biochemical, hematological and histological changes but most of these were reversible when exposure was terminated.

Animals↗
PubMedDate not supplied

Long-term preservation of egg and tissue homogenates for determination of organochlorine compounds: freezing versus freeze-drying.

Storage of wet egg homogenates at temperatures from -18 degrees to -28 degrees C was more suitable for long-term preservation than freeze-drying. Changes in residue levels of heptachlor epoxide, oxychlordane, dieldrin, hexachlorobenzene,p,p'-DDE, mirex, and PCBs were not significant over a 3-year period in fresh herring gull egg homogenates stored at -18 degrees to -28 degrees C. Compounds with gas chromatographic retention times shorter than hexachlorobenzene vaporized during freeze-drying at a rate proportional to their volatility. Evaporative losses of components with vapor pressures less than hexachlorobenzene did not occur in naturally contaminated herring gull eggs after storage at room temperature for up to 1 year. Higher losses of all compounds, up to 25% for p,p'-DDE, occurred in freeze-dried whole-body herring gull homogenates. Easily dehydrochlorinated compounds were rapidly degraded in freeze-dried chicken egg homogenate at room temperature: The half-life of p,p'-DDT and p,p'-DDD was about 20 days, and that of alpha- and gamma-hexachlorocyclohexane was much less than 16 days. About one-third of oxychlordane in herring gull eggs was lost in 1 year under these conditions, but none was lost after freeze-drying when the homogenate was stored at -18 degrees to -28 degrees C.

Eggs↗