Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
The genotoxicity and/or toxicity of benzo(a)pyrene (BaP) were evaluated under different lighting conditions in larvae and embryos of the newt Pleurodeles waltl. Visible light alone (1,220 lx; 2.1 mW/cm2), UVA alone (250 microW/cm2), or BaP alone (500, 50, 25, 12.5 ppb) had no toxic effects on the larvae. Conversely, toxic effects were observed in animals exposed to BaP (500 ppb)+daylight, or BaP (> or = 25 ppb)+UVA. BaP solutions (50 or 12.5 ppb) were irradiated for 24 hr (Irr BaP) prior to being assayed in the dark. The genotoxicity of BaP (50 ppb) as evaluated in the micronucleus test (on day 8) was halved by its previous exposure to UVA, and was abolished at the lowest concentration (12.5 ppb). In other experiments, the larvae were exposed alternatively to BaP or Irr BaP (18 hr in the dark) and UVA (6 hr in water), every day for 8 days. All animals that had accumulated non-irradiated BaP (50 ppb) showed signs of severe toxicity, and 90% died before the end of the test. On the other hand, irradiated BaP (50 ppb) was 4-fold less toxic and half as genotoxic as non-irradiated BaP. In addition, exposure of the animals to UVA alone for 4 days prior to treatment with BaP did not affect the genotoxicity or toxicity of this hydrocarbon. In the dark, the embryotoxicity of BaP was markedly attenuated by the presence of the jelly coats (10% vs. 24%). With dejellied embryos, comparable mortality (24%) was observed after exposure to 25 ppb BaP for 54 or 312 hr. Although UVA alone did not affect growth of the embryos, the toxicity of BaP was enhanced by the combined action of the two agents together or in succession (BaP+UVA or BaP then UVA). Larvae were treated with an oil refinery effluent (EF). At the concentration employed (125 ml/l), EF was not found to be genotoxic in the dark. However, in animals exposed to both EF and UVA, there was a progressive increase in level of micronucleated erythrocytes with increasing duration of daily exposure to UVA (9, 15, 24 hr). Moreover, the genotoxic potential of irradiated EF+UVA was systematically below that of non-irradiated EF+UVA for all durations of exposure to ultraviolet light. Irradiation of this type of effluent might help reduce its harmful effects on aquatic species. Our results also suggest that metabolic activation is not necessary for hydrocarbons to induce toxic effects.
The genotoxicity and/or toxicity of benzo(a)pyrene (BaP) were evaluated under different lighting conditions in larvae and embryos of the newt Pleurodeles waltl. Visible light alone (1,220 lx; 2.1 mW/cm2), UVA alone (250 microW/cm2), or BaP alone (500, 50, 25, 12.5 ppb) had no toxic effects on the larvae. Conversely, toxic effects were observed in animals exposed to BaP (500 ppb)+daylight, or BaP (> or = 25 ppb)+UVA. BaP solutions (50 or 12.5 ppb) were irradiated for 24 hr (Irr BaP) prior to being assayed in the dark. The genotoxicity of BaP (50 ppb) as evaluated in the micronucleus test (on day 8) was halved by its previous exposure to UVA, and was abolished at the lowest concentration (12.5 ppb). In other experiments, the larvae were exposed alternatively to BaP or Irr BaP (18 hr in the dark) and UVA (6 hr in water), every day for 8 days. All animals that had accumulated non-irradiated BaP (50 ppb) showed signs of severe toxicity, and 90% died before the end of the test. On the other hand, irradiated BaP (50 ppb) was 4-fold less toxic and half as genotoxic as non-irradiated BaP. In addition, exposure of the animals to UVA alone for 4 days prior to treatment with BaP did not affect the genotoxicity or toxicity of this hydrocarbon. In the dark, the embryotoxicity of BaP was markedly attenuated by the presence of the jelly coats (10% vs. 24%). With dejellied embryos, comparable mortality (24%) was observed after exposure to 25 ppb BaP for 54 or 312 hr. Although UVA alone did not affect growth of the embryos, the toxicity of BaP was enhanced by the combined action of the two agents together or in succession (BaP+UVA or BaP then UVA). Larvae were treated with an oil refinery effluent (EF). At the concentration employed (125 ml/l), EF was not found to be genotoxic in the dark. However, in animals exposed to both EF and UVA, there was a progressive increase in level of micronucleated erythrocytes with increasing duration of daily exposure to UVA (9, 15, 24 hr). Moreover, the genotoxic potential of irradiated EF+UVA was systematically below that of non-irradiated EF+UVA for all durations of exposure to ultraviolet light. Irradiation of this type of effluent might help reduce its harmful effects on aquatic species. Our results also suggest that metabolic activation is not necessary for hydrocarbons to induce toxic effects.
A knowledge of the fate of a drug, its disposition (absorption, distribution, metabolism, and excretion, known by the acronym ADME) and pharmacokinetics (the mathematical description of the rates of these processes and of concentration-time relationships), plays a central role throughout pharmaceutical research and development. These studies aid in the discovery and selection of new chemical entities, support safety assessment, and are critical in defining conditions for safe and effective use in patients. ADME studies provide the only basis for critical judgments from situations where the behavior of the drug is understood to those where it is unknown: this is most important in bridging from animal studies to the human situation. This presentation is intended to provide an introductory overview of the life cycle of a drug in the animal body and indicates the significance of such information for a full understanding of mechanisms of action and toxicity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.