Showing papers in "Chemico-Biological Interactions in 1973"

TL;DR: Epoxide hydrase activity is elevated substantially by pretreatment of rats with phenobarbital and to a lesser extent by pret treatment with 3-methylcholanthrene, and co-administration of cyclohexene oxide and chlorobenzene significantly reduces the rate of metabolism of [14C]chlorobenzenes and prevents the hepatic centrilobular necrosis caused by chlorobazene in rats.

TL;DR: Caffeine is found to reverse the alkylation-induced delay of DNA synthesis in both SM- and MNU-alkylated Chinese hamster cells, and it is proposed that caffeine sensitizes alkylated cells by inhibition of a post-replication DNA repair mechanism.

TL;DR: A concept is developed which suggests that all basic amines (group I) are oxidised by a flavine adenine nucleotide (FAD)-dependent enzyme system, whereas non-basic nitrogen-containing compounds (group III) are oxidation by a cytochrome P450-dependent system.

TL;DR: The hamster and perhaps other rodent cells exposed to low doses of UV are capable of DNA replication, by-passing the non-excised pyrimidine dimers, and the postulated repair process probably involves de novo DNA synthesis to seal the gaps in the nascent strand.

TL;DR: Enzymatic activities of liver microsomal preparations converting retrorsine to pyrrolic metabolites in vitro varied considerably between species but did not always correlate with the levels of bound pyr rolic metabolites formed in vivo following the administration of retrorine.

TL;DR: Comparison of C3H3 and 14CH3 labelling showed that the ratio 3H14C in the products was the same and equal to that in the original reagents, in accord with the concept that the methyl group is transferred intact, and not via diazomethane.

TL;DR: A comparison of guanine and derivatives in which the N-7, N-9 or both positions were blocked indicates that probably more than one site is available for reaction with Pt(en)Cl 2 .

TL;DR: The results are compatible with the hypothesis that CS2 requires metabolism for its liver toxicity, and the loss of the cytochrome observed with NADPH alone, which is associated with the formation of malonaldehyde, that due to CS2 still occurred in the presence of EDTA, even though the Formation ofmalonaldehyde was largely prevented.

TL;DR: Evidence is presented that the assay of urinary alkaline and acid phosphatase is the most sensitive method of detecting renal tubular damage in the dog.

TL;DR: Cytochrome P-450 difference spectra were obtained with microsomes prepared from several strains of the housefly, Musca domestica, that were susceptible or resistant to insecticides, and no correlation could be made between strains having known high mixed-function oxidase activity and any single cytochromeP-450 spectral characteristic.

TL;DR: The major site of inhibition of electron transport appeared to be between cytochromes b and c (c1) as indicated by comparison of systems employing various substrates which donate their electrons to various portions of the electron transport system.

TL;DR: Evidence is presented that the assay of N -acetyl-β-glucosaminidase activity in the serum and urine and the measurement of specific gravity of the urine provide the most sensitive method for the detection of papillary damage in the dog.

TL;DR: The susceptibilities of rats of various ages to hepatotoxic effects of retrorsine were compatible with the capacities of their livers to form and retain pyrrolic metabolites from the alkaloid in vivo, although young rats (under about 20 days) were more sensitive than older animals.

TL;DR: Adenine and adenosine react very slowly at 37° whereas other adenine derivatives react much more readily in the order: poly A > AMP > ApA > poly d(AT).

TL;DR: The results suggest that the ability of a given compound to induce drug metabolism is not only related to lipid solubility and pharmacokinetic characteristics but also to the nature of chemical groups present in the molecule.

TL;DR: Inhibition of protein synthesis by aflatoxin B1 was not secondary to other changes in the cell but was due to a direct action of the toxin on the polysomes.

TL;DR: Microsomal fractions were isolated from hepatic tissue, housefly abdomen and southern armyworm midgut by centrifugation of post-mitochondrial supernatant for 1 h at 105 000× g or by calcium sedimentation and low speed centrifugations.

TL;DR: Correlation of crystal structure analyses and model building of rigid molecules indicate the structural requirements for curariform activity and the structural differences between depolarizing and non-depolarizing neuromuscular blocking agents.

TL;DR: The binding of ethyl carbamate labelled with carbon-14 in the alkyl or carbonyl group to the DNA of mouse liver, lung and kidney has been studied in male Crackenbush mice and it was concluded that the bound molecule is probably an ethyl group.

TL;DR: The results of quantitative structure-activity analysis show that the potency of polycyclic hydrocarbons as inducers of microsomal arylhydrocarbon hydroxylase (AHH) can be quantitatively described in terms of hydrophobic interactions, chemical reactivity, and the ability to participate in charge-transfer interactions.

TL;DR: Observations support the suggestion that hydrolysis is the first step in the interaction of biologically active complexes with the components of living systems.

TL;DR: The hypothesis that the possible contribution given by the enhancement of lipid peroxidation to the pathogenesis of CCl 4 -induced fatty liver could depend on further structural and functional alterations occurring in the cytoplasmic environment of hepatocytes rather than the early radical attack onto the unsaturated lipids of liver microsomes is supported.

TL;DR: The data suggest that cis-PPC or cis -Pt(II) may associate with electron-rich areas of not only nucleic acids and proteins but also with body pools of free nucleotides and amino acids.

TL;DR: In this article, structure-activity relationships have been studied for a series of doubly charged, fully co-ordinated, 1,10-phenanthroline transition metal chelates differing in the metal ion or in the number and nature of the substituent groups present on the ligand by assaying their ability to inhibit the multiplication of influenza virus in chick allantoic cells.

TL;DR: Evidence is presented that the biologically effective concentration of a drug is that which binds to the cell surface, and the implications of the solubility and other physical properties of the alkylating agents are discussed.

TL;DR: Results obtained by alkylation under conditions where the native configuration of the tRNA was maintained show that the tertiary structure of the nucleic acid does not impart any specificity to the reaction with the nitrosamide producing 7-alkylguanine but the possibility that such specificity does exist for the minor products of alkylated tRNA cannot be excluded.