Showing papers in "Chemico-Biological Interactions in 1970"

TL;DR: The ability of the alkylating agent-resistant sub-line of the Yoshida sarcoma to recover from DNA alkylation by mustard gas has been compared with the original drug-sensitive tumour line to explain the observed 20-fold difference in drug sensitivity in terms of DNA repair mechanisms.

TL;DR: The mechanism for C - and N -oxygenation and the release of electrophilic metabolites associated with the latter process is discussed and the electron-donor properties of aromatic amines are discussed.

TL;DR: A heterogeneous composition and specialization of smooth rat liver microsomes is apparent in the control rat and also in the differential response of these membranes to phenobarbital and 3-methylcholanthrene induction.

TL;DR: A new drug-metabolizing enzyme that hydroxylates coumarin in position 3 of the ring has been demonstrated in the liver of the rat and the activity returned to normal within 2 weeks of cessation of treatment.

TL;DR: Some of the observed changes appear to be related to those previously observed in preneoplastic liver cells and hepatoma cells of 2-AAF-treated rats and may, therefore, berelated to the carcinogenic activity of 1-AAF.

TL;DR: Radioactivity of injected [14C]DMNA was also associated with the guanine and adenine skeletons; in the DNA of the susceptible lung the specific radioactivities of both purines were appreciably higher than in theDNA of the resistant lung.

TL;DR: The data suggest a covalent binding of 4NQO or its derivatives with purine bases of DNA, which was not adsorbed on DEAE-cellulose column chromatography.

TL;DR: The ribosomal RNA appears to become degraded after the development of a drug-induced autophagic vacuole in the cell while RNA species of higher eiectrophoretic mobility increased in amount.

TL;DR: ANS was not found to be a substrate of the hepatic microsomal NADPH-dependent oxidase system, but was an inhibitor of certain microsome enzymes when added to incubation mixtures in vitro.

TL;DR: It is concluded that two types of DAB-reductase activity exist, one which is sensitive to the toxic action of Dab and which is more concentrated in the smooth microsomes, and another which is unaffected by DAB metabolites andWhich is the NADPH-cytochrome c reductase flavoprotein.

TL;DR: The experiments suggest that the selective unmas-king was related to an intercalative deformation of RNA-helices, while the unspecific reaction was due to a more general interference of positively charged aromatic compounds with the tertiary RNA structure.

TL;DR: Evidence is presented that methionyl-tRNA synthetase of rabbit reticulocytes can exist in different polymeric states and phosphonic acid analogues of isoleucine, valine and leucine were shown, for the first time, to be specific inhibitors of the corresponding aminoacyl-t RNA synthetases.

TL;DR: The halogenated triphosphate not only exerted a greater inhibitory effect than deoxythymidine triph phosphate, but also afforded greater protection to thermal inactivation.

TL;DR: Phenobarbital in vitro is without effect on either the 5'-UMPase activity of the microsomes or the ribonuclease activity of cellular fractions.

TL;DR: No recovery from sub-lethal damage could be demonstrated in spite of the presence of a significant shoulder on the dose response curve for HeLa cells treated with isopropyl methanesulphonate (IMS), a compound with a short half hydrolysis time.

TL;DR: It appears that insulin secretion may proceed from several (or at least from two) ultrastructural events according to the preparation and/or the stimulus used, and intracytoplasmic release of secretory material through intracellular solubilization of β-granules is the predominant mode of insulin secretion in cultured fetal explants.

TL;DR: It appears that for tumour development a proliferative response must occur in the presence of carcinogen.

TL;DR: A theory involving the linkage of two cellular entities by the dimethanesulphonoxy-alkanes is discussed in an attempt to explain the mode of action of this chemical series.

TL;DR: The binding of [3H]ortho-aminoazotoluene to liver DNA, RNA and protein was similar to that in non-hepatectomised mice during the periods of increased DNA synthesis and the second period of increased mitosis.

TL;DR: The results suggest that the synthesis of pre-ribosomal RNA in the nucleolus proceeds but that its further processing is impaired.

TL;DR: P,p'-DDMU [1,1-di(4-chlorophenyl)-2-chloroethylene] exhibited anomalous behaviour in causing elevated G-6-P dehydrogenase levels, which may be due to interference in protein metabolism primarily by the unsaturated analogues and metabolites of p,p-DDT.

TL;DR: Findings suggest that the larvicidal and chemosterilant activities of filipin are due to the formation of a complex of Filipin and cholesterol which prevent the uptake and utilization of sufficient dietary cholesterol for vital processes.

TL;DR: When strain and organ specificity are varied the levels of binding to DNA, RNA and protein correlate well with carcinogenicity, as shown in mice injected with tritiated 2-naphthylamine.

TL;DR: The findings suggest that the normal RNA-DNA ratio in the livers of rats fed both 3'MeDAB and chloramphenicol might be relevant to the protection against hepatocarcinogenesis afforded by this drug.

TL;DR: It is shown that Adrenal-dependent stress, which can be induced by carcinogenic amines in vivo, amplifies the shift towards the deleterious N-oxygenation pathway caused by electrophilic agents in microsomal systems.