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Biomedical subjects

G C Becking

Publications and source records attributed to G C Becking.

48 records · Page 3Linked to original sources
PubMedDate not supplied

Ninety-day toxicity of photomirex in the male rat.

Photomirex (8-monohydromirex) is a demonstrated environmental contaminant and was observed in previous short-term studies to produce lesions in the liver, thyroid and testes of male rats. The present study was undertaken to confirm those observations and to determine the effects after a longer period of exposure. Male rats were fed photomirex for 13 weeks at levels of 0.20, 1.0, 5.0, 25 and 125 ppm in the diet. Deaths were observed in animals receiving the highest dose. Decreased body weight gain and food intake were also observed in that group. Liver weights were increased at 5.0 ppm photomirex and higher. Photomirex caused changes in several biochemical parameters including serum sorbitol dehydrogenase and hepatic aniline hydroxylase activities. Dose-related histological abnormalities were observed in the thyroid and liver starting at the lowest dose level. These results confirm earlier findings and show that photomirex is a potent hepato- and thyrotoxin.

Aniline Hydroxylase↗
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

The absorption, distribution and excretion of photomirex in the rat.

The absorption, distribution, and excretion of photomirex were investigated in the rat. Photomirex was absorbed slowly after oral administration, appeared in the blood at 1.5 hr, and reached the peak concentration 4 hr after dosing. Elimination from the blood was studied in rats receiving single intravenous doses; the semilog-arithmic decay curve was found to be triphasic. The highest concentrations were present in the rat, liver, and skin. Approximately 38--42% of the orally dosed photomirex was excreted in the feces in the first 3 days and 51--55% was eliminated in 28 days. Only trace amounts of photomirex were found in the urine (less than 0.09% of the total dose in 24 hr). Photomirex constituted about 95% of the total radioactivity found in the tissues and feces. No metabolite was detected in the radioactive material extracted from tissues or feces.

Animals↗