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Biomedical subjects

D A Wright

Publications and source records attributed to D A Wright.

116 records · Page 7Linked to original sources
PubMedDate not supplied

Effects of tributyltin on survival, growth, morphometry, and RNA-DNA ratio of larval striped bass, Morone saxatilis.

Effects of tributyltin (TBT) on survival, growth, morphometry, and RNA-DNA ratio in larval striped bass (Morone saxatilis) were assessed in three experiments. In Experiment I, 13 day old larvae were exposed to 0, 0.067, 0.766, or 2.284 micrograms TBT/L for 6 days. All larvae exposed to 2.284 micrograms/L died by day 5; exposure to 0.766 micrograms/L significantly reduced survival relative to controls (59.8% vs. 81.8%). Significant, concentration-dependent decreases in body depth occurred in larvae exposed to 0.067 and 0.766 micrograms/L. In Experiment II, all 16 day old larvae exposed to 1.498 micrograms/L died by day 6. Survival, weight, and morphometry parameters were not significantly different in larvae exposed to 0, 0.052, or 0.444 micrograms/L for 6 days. In Experiment III, survival was similar in 21 day old larvae exposed to 0, 0.055, 0.281, or 0.514 micrograms/L for 7 days. Notochord length and dry weight decreased significantly in larvae exposed to 0.514 micrograms/L. Weight and morphometry parameters were more sensitive indicators of sublethal stress than RNA-DNA ratio. Maximum TBT concentrations reported in Chesapeake Bay marinas are likely to cause increased larval mortality. Longer-term studies are needed to assess effects at less than 0.050 micrograms/L, which may be more representative of habitat conditions.

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PubMedDate not supplied

Effect of dietary cholesterol on apolipoprotein E synthesis in the rabbit.

Female New Zealand White rabbits were fed either rabbit chow or rabbit chow plus 1% (w/w) cholesterol for 14 days. The chow-fed rabbits had normal plasma lipoprotein profiles on agarose gel electrophoresis, 59 +/- 5 mg of cholesterol and 5.5 +/- 0.4 mg of apolipoprotein E (apoE) per dl of serum. The cholesterol-fed rabbits had significant amounts of beta-VLDL in their serum, 1870 +/- 140 mg of cholesterol and 96 +/- 12 mg of apoE per dl of serum. Relative rates of apoE synthesis were determined by incubating hepatocytes in culture medium containing [3H]leucine for 15 min at 37 degrees C and expressing the radioactivity incorporated into immunoprecipitable apoE as a percentage of the radioactivity incorporated into total protein. Hepatocytes from cholesterol-fed rabbits had twice the relative rate of apoE synthesis (1.05 +/- 0.18%) of hepatocytes from chow-fed rabbits (0.55 +/- 0.07%). This increase in synthesis could be a major contributor to the 17-fold increase in serum apoE levels in the cholesterol-fed rabbit.

Animals↗
PubMedDate not supplied

Pathology of fathead minnows (Pimephales promelas) exposed to chlorine dioxide and chlorite.

Fathead minnows (Pimephales promelas) were exposed to the biocide chlorine dioxide (0.13 and 0.19 mg l-1) for up to 12 h and to its primary decomposition product, chlorite (177 and 304 mg l-1), for up to 96 h followed by recovery periods of up to 14 days. Chlorine dioxide exposure produced dose-dependent gill pathology including epithelial lifting, hypertrophy, hyperplasia, lamellar fusion, and necrosis. Complete recovery, even in fish with severe hypertrophy and lamellar fusion, was achieved within 4 days. Chlorite did not produce gill pathology even at a lethal exposure level (304 mg l-1 for 96 h) but did elicit a chronic inflammatory response with a marked increase in circulating and fixed phagocytes within hematopoietic and vascular tissues. This study indicates that chlorine dioxide is approximately 1000 times more toxic to fathead minnows than chlorite. Further, exposure of fathead minnows to these distinct but related compounds is consistently associated with very different pathologies.

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