DNA-damaging activities of twenty-four structurally diverse unsubstituted and substituted cyclic compounds in embryo-fetal chicken livers.

DNA-damaging activities of twenty-four structurally diverse unsubstituted and substituted cyclic compounds were assessed in embryo-fetal chicken livers. Formation of DNA adducts and strand breaks were measured using the nucleotide P-postlabelling (NPL) and comet assays, respectively. Unsubstituted monocyclic benzene, polycyclic fused ring compound naphthalene, covalently connected polycyclic ring compound biphenyl, and heterocyclic ring compound fluorene did not produce DNA damage.

Assessment and characterization of DNA adducts produced by alkenylbenzenes in fetal turkey and chicken livers.

Formation of DNA adducts by five alkenylbenzenes, safrole, methyl eugenol, eugenol, and asarone with either α- or β-conformation, was analyzed in fetal avian livers in two in ovo models. DNA reactivity of the carcinogens safrole and methyl eugenol was previously demonstrated in the turkey egg model, whereas non-genotoxic eugenol was negative. In the current study, alkenylbenzenes were also tested in the chicken egg model.

Expression of Genes Encoding for Xenobiotic Metabolism After Exposure to Dialkylnitrosamines in the Chicken Egg Genotoxicity Alternative Model.

The Chicken Egg Genotoxicity Assay (CEGA) demonstrated responsiveness to various DNA-reactive chemicals requiring metabolic activation, which implies broad bioactivation capability. To assess potential metabolic competence, expression profiles of metabolic genes in the embryo-chicken fetal liver were determined using microarray technology. Fertilized chicken eggs were injected under the CEGA protocol with vehicle (deionized water [DW]), the activation-dependent carcinogens, diethylnitrosamine (DEN), and N-nitrosodiethanolamine (NDELA) at doses producing no effect on survival.

In ovo testing of flavor and fragrance materials in Turkey Egg Genotoxicity Assay (TEGA), comparison of results to in vitro and in vivo data.

Genotoxicity of flavor and fragrance materials was assessed in Turkey Egg Genotoxicity Assay (TEGA) using P-nucleotide postlabeling (NPL) and comet assays to detect hepatic DNA adducts and strand breaks. Twenty materials having results in GADD45a-Gluc 'BlueScreen HC' genotoxicity assay, and standard in vitro and in vivo tests, were selected to evaluate the accuracy of TEGA. Quinoline (QUI) and 2-acetylaminofluorene (AAF) served as positive comparators.

Chicken egg fetal liver DNA and histopathologic effects of structurally diverse carcinogens and non-carcinogens.

Chicken egg fetal livers were evaluated for histopathological changes produced by four genotoxic hepatocarcinogens: 2-acetylaminofluorene (AAF), aflatoxin B (AFB), benzo[a]pyrene (BaP), diethylnitrosamine (DEN); four structurally related non- or weakly- carcinogenic comparators: fluorene (FLU), aflatoxin B (AFB), benzo[e]pyrene (BeP), N-nitrosodiethanolamine (NDELA); two epigenetic hepatocarcinogens: clofibric acid (CFA), phenobarbital (PB); and the non-carcinogen, D-mannitol (MAN). CFA, PB and MAN were also assessed for formation of DNA adducts using the P nucleotide postlabeling (NPL) assay and for DNA breaks using the comet assay. CFA was also assessed in enhanced comet assay for oxidative DNA damage induction.