摘要:

Caenorhabditis eleganshas proven useful in toxicity testing of known toxicants, but its potential for assessing the toxicity of new pharmaceuticals is relatively unexplored. In this study the procedures used in aquatic testing of toxicants were modified to permit testing of small amounts (<40 mg) of gadolinium-based magnetic resonance imaging (MRI) compounds. Five blinded compounds were tested. The toxicity of these compounds determined usingC. eleganswas compared to existing mammalian test system data (minimum lethal dose [MLD] values for mice). Four of five compounds tested had the same relative sensitivity withC. elegansas with the mouse test system. Testing withC. elegansis efficient and could markedly reduce the cost of screening potentially useful compounds.

ISSN:1528-7394    

DOI:10.1080/00984100050195125

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Hepatic cytochrome P-450 (CYP450) isozymes are involved in xenobiotic detoxification and steroid metabolism. Seals are highly exposed to polychlorinated biphenyls (PCBs) in the environment, resulting in CYP450 induction, which may have concomitant effects on CYP450 steroid metabolism. Experiments were conducted to determine rates of steroid metabolism in harbor seal (Phoca vitulina

ISSN:1528-7394    

DOI:10.1080/00984100050195134

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants that accumulate to toxic levels in the food chain. UsingSpisula solidissima(surf clam) embryos as a developmental model, it was shown that Aroclor 1254 specifically targets two neuronal structures during embryonic development. Embryos were exposed to 1, 10, or 100 ppm Aroclor 1254 or an acetone vehicle control posthatching for 24, 48, and 72 h. Embryos labeled with a serotonin antibody or a neural antigen antibody and a rhodamine-conjugated secondary antibody were viewed by confocal microscopy. The cerebropleural ganglion showed a decrease both in serotonin production and in the size of the serotonin-synthesizing region upon exposure to 10 and 100 ppm Aroclor 1254. These decreases were detectable as early as 48 h postfertilization. When exposed to 100 ppm Aroclor 1254, the primitive neural plexus, which coordinates the movements of the mouth and velum, showed a delay in onset and cessation of expression of a molluscan-specific neural antigen. Exposure to Aroclor 1254 did not affect the overall growth and morphology of the embryos. In addition, analyses of total protein profiles and heat-shock protein 70 levels showed that exposure to Aroclor 1254 did not trigger protein degradation or cause a stress or shock response. These results show that exposure of Spisula embryos to Aroclor 1254 specifically targets neurogenesis while having no effect on the overall growth of the embryo.

ISSN:1528-7394    

DOI:10.1080/00984100050195143

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

ISSN:1528-7394    

DOI:10.1080/00984100050195152

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

ISSN:1528-7394    

DOI:10.1080/00984100050195161

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor

摘要:

Styrene is a widely used chemical that has been shown to cause lung tumors in mice but not in rats. Styrene toxicity appears to be related to its bioactivation to styrene oxide, and this occurs almost exclusively in Clara cells. An important pathway in the detoxification of styrene oxide is via epoxide hydrolase to yield styrene glycol. When mouse Clara cells were incubated with racemic styrene oxide,R-styrene glycol was the predominant metabolite, giving anR/Sratio of 3.6. When the pure styrene oxide enantiomers were used as substrates, the corresponding styrene glycols were the predominant but not exclusive metabolites. Activity was slightly higher with theS-styrene oxide than with theR-styrene oxide. Addition of reduced glutathione to the incubation medium resulted in an increase in epoxide hydrolase activity, perhaps by decreasing oxidative stress. Mouse Clara cells thus show the capacity for detoxifying styrene oxide.

ISSN:1528-7394    

DOI:10.1080/00984100050195170

出版商:Informa UK Ltd    

年代:2000

数据来源: Taylor