Showing papers in "Chemico-Biological Interactions in 1981"

TL;DR: These findings are further support of the previous postulate that GSH depletion per se might lead to an increased lipid peroxidation, possibly due to its lack as a part of the cellular defence system against endogenous toxic intermediates.

TL;DR: Data imply that chromate crosses the cell membrane, is reduced to the trivalent form and induces stable linkages of DNA to protein.

TL;DR: It was concluded that the most stable conformation of all biphenyls with or without ortho-substitutents is non-planar and that neigher planarity nor symmetry is an inherent requirement for receptor binding.

TL;DR: In this article, the role of urinary versus biliary excretion of N-hydroxy arylamines in relation to bladder and colon carcinogenesis was discussed. And the authors showed that 2-NA and 2-NN appear to share common metabolic pathways which yield free N-HO-2-NA as a putative ultimate urinary bladder carcinogen.

TL;DR: The binding of chemical carcinogen and mutagen hemoglobin would appear to be generic so that it could be developed into a dose monitor for a large number of known carcinogens and mutagens.

TL;DR: The uptake and concentration of radioactivity associated with hydroquinone and catechol by bone marrow and lymphoid organs can occur independently of the metabolism of benzene in these tissues and is reduced under conditions in which the animal is less susceptible to benzene toxicity.

TL;DR: It is concluded that the compound described by these authors, 7-N-(2-oxoethyl)guanine is in fact the major product of base alkylation in DNA after exposure to vinyl chloride.

TL;DR: The results suggest that PCB isomers and congeners substituted at at least two meta positions, at two ortho positions and containing a 2,3-4-trichloro substitution pattern on one ring are mixed-type inducers; in addition, the effects of 2,2',3,4,4',5,6-hexachlorobiphenyl were also consistent with a mixed pattern of induction.

TL;DR: Only those isomers producing testicular damage were found to alter zinc metabolism by increasing the urinary excretion of zinc and by depleting the concentration of this element in testicular tissues.

TL;DR: The data show that human cells can recover from cisplatin toxicity and that, during recovery, cells repair interstrand cross-links and remove platinum adducts from DNA, suggesting that cytotoxicity is a function of the amount of damage remaining in DNA at the time that cells enter the proliferative cycle.

TL;DR: Carbonyl compounds released during the NADPH-Fe dependent peroxidation of liver microsomal lipids and identified as 4-hydroxyalkenals inhibit protein synthesis in a rabbit reticulocyte lysate.

TL;DR: The present results are consistent with lipid peroxidation being a major contributory factor to the decrease in glucose-6-phosphatase activity observed in CCl4-induced liver injury.

TL;DR: These studies provide further evidence that drug-metabolizing activities in fish liver are readily induced by chemicals like TCDD or PAH, but they fail to demonstrate induction after treatment of sheepshead with inducers of the PB type.

TL;DR: Cytochrome P-450 of glutamic acid pyrolysis products, 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole (Glu-P-2), to mutagenic metabolites was studied using Salmonella typhimurium TA98 as a tester strain.

TL;DR: It is stressed that Cr(VI), if not completely reduced to Cr(III) by extracellular and endoplasmic constituents, can reach the cell nucleus and directly interact with DNA.

TL;DR: Variability in the induction response to the various pretreatment was observed among the three strains, whereas the activities of epoxide hydrolase and glutathione-S-transferase in control larvae were comparable in the different strains,Whereas the content of cytochrome P-450 and BP monooxygenase activity was higher in the Hikone R strain.

TL;DR: The changes in the level of protein binding in vitro brought about by these pretreatments are quantitatively similar to the relative changes in AFB1-dihydrodiol tris complex production induced by the two compounds indicating a role for this metabolite in protein binding.

TL;DR: The results indicate that the mutagenic effect of a chemical is not dependent simply on the quantity of theAdducts, but may vary with structure of its adducts.

TL;DR: The distinctive induction of nucleotide excision repair and base excison repair prior to the onset of DNA replication suggests that separate DNA repair complexes may be formed during the eucaryotic cell cycle.

TL;DR: Chinese hamster ovary cells in cell culture were utilized to study the cytotoxic and mutagenic activity of benzo[a]pyrene and the dependence of the induction of 6-thioguanine(TG)-resistant mutants on parameters such as BP concentration, amount of S9 protein, ionic composition of the S9 mix and treatment time was determined.

TL;DR: The results suggest that carbanions are not formed as major intermediates and suggest that one-electron transfer reactions predominate in the reductive metabolism of carbon tetrachloride and halothane.

TL;DR: It appeared that the exposure to polycyclic aromatic hydrocarbons, especially the carcinogenic ones, was followed by synthesis of a new aldehyde dehydrogenase form, differentiated from the normally existing cytosolic alde Hyde dehydrogen enzyme by its ability to oxidize benzaldehyde in the presence of NADP.

TL;DR: The qualitative and quantitative effects of various modulators of metabolism (enzyme inhibitors, apparently homogeneous epoxide hydrolase, glutathione, supernatant fraction) were investigated and the results are discussed with respect to possible ultimate carcinogens.

TL;DR: It is suggested that hepatic Zn-thionein has an essential function in the Zn metabolism of the liver, but is unlikely to control the supply of Zn to other organs in the newborn rat.

TL;DR: The method is suitable for measuring the incorporation of other radiolabelled xenobiotics to proteins of both microsomes and other subcellular fractions and for the analysis of binding to isolated proteins.

TL;DR: An important role for glucuronidation and sulfation in the inactivation and elimination of polycyclic aromatic hydrocarbons is suggested.

TL;DR: The studies suggest that the hydroxylamine is probably the reactive reduction metabolite responsible for the in vivo and in vitro binding of misonidazole to cellular macromolecules.

TL;DR: Results obtained from experiments indicated the involvement of the cytochrome P -450-dependent monooxygenases in the metabolism of precocene II and the concurrent covalent binding and a highly reactive (3,4-epoxy-6,7-dimethoxy-2,2-dimethylchromane (precocene-3, 4-epoxide) was thus suggested as a crucial metabolic intermediate which may be responsible for the histopathological changes seen in rat liver.

TL;DR: The use of tyrosinase provides a convenient model for the detection of the actual inhibitory interaction of a free-radical (semiquinone) with a biologically important macromolecule, reverse transcriptase, and suggests that the common intermediate of oxidation ofQuinols or reduction of quinones is the active species.

TL;DR: Low-temperature whole-body autoradiography and autoradography with heated sections in C57Bl mice injected with N-[14C]nitrosodiethylamine showed a homogenously distributed volatile radioactivity in most tissues--indicating an ability of the non-metabolized substance to freely pass the biological membranes and distribute evenly in the intra- and extracellular tissue-water.