Showing papers in "Chemico-Biological Interactions in 1977"

TL;DR: The stereospecificity of both the monoxygenase system and, to a lesser extent, epoxide hydrase plays important roles in the metabolic activation of benzo[a]pyrene to carcinogens and mutagens.

TL;DR: An enhanced production of superoxide and hydrogen peroxide and the relatively low catalase content of heart tissue may be factors in the cardiotoxicity induced by adriamycin chemotherapy if a similar reaction occurs in vivo.

TL;DR: Isomers which are chlorinated in only one ring, or are chlorination in both rings but not in the para positions, have very little activity as inducers of liver enzymes.

TL;DR: Electron microscopic studies showed that both paraquat and diquat damage type I alveolar cells, but only paraqu at produces type II cell lesions, and there seems not to exist a straightforward relationship between this event and cell damage.

TL;DR: The liver was chosen as a model system since it is the main organ for the metabolism of foreign compounds containing all the enzymes necessary for an activation and since this organ provides ample DN A for the determination of low specific radioactivity.

TL;DR: There appears to be a relationship between the inhibition of tumor promotion and epidermal DNA synthesis, with fluocinolone acetonide not quite as effective on S-phase cells as on G-1 cells.

TL;DR: The results show that the hydrocarbon-nucleic acid products formed in mouse skin in vivo most probably arise from 3,4-dihydro-3, 4- dihydroxy-7-methylbenz(a)anthracene 1,2-oxide which, on the basis of this and other evidence, appears to be the reactive intermediate involved in the metabolic activation of 7- methylbenz (a) anthracene in this tissue.

TL;DR: It is suggested that the changes in the polarity and in the DNA binding ability of these derivatives are the main factors accounting for the difference in the in vivo activity of daunorubicin, adriamycin, and stereoisomers.

TL;DR: The present study shows that saccharin does not undergo a covalent binding to DNA of the liver or the bladder of male rats either, and the tumor induction is therefore probably due to a secondary darnage to the bladder.

TL;DR: Tissue accumulation, subcellular incorporation and soluble protein binding of 203Hg and 75Se in the liver and kidney were studied and PMA and MMC gave different changes suggesting that their interactions with selenite were indeed complex.

TL;DR: Evidence is presented supporting the similarity of this protein with mammalian metallothionein, and a major proportion of the water-soluble cadmium and copper in these molluscs is associated with a protein of molecular weight 10 800 daltons.

TL;DR: Evidence suggesting a shift of 75Se from the cytosol to the mitochondrial fraction in brain when CH3Hg+ was given is suggested, although a considerable portion of both isotopes eluted with proteins in the void vulume.

TL;DR: A Short Review is given of the biochemical neurotoxic mechanisms of common industrial solvents of various structures and the stability of the toxic metabolites appears to correlate with the development of neuropathy although this is structuredependent.

TL;DR: The pesticide pentachlorophenol known as an uncoupler of mitochondrial oxidative phosphorylation was shown to disturb liver microsomal detoxication functions by a selective inhibition of the terminal oxygenation enzyme P-450, suggesting the possible synergistic influence of chlorophenols on the carcinogenic effects of polyaromatic amines and hydrocarbons.

TL;DR: It is suggested that toxicity and DNA damage may result from the actions of toxic intermediates in the metabolic reduction of nitrofurans.

TL;DR: Administration of several vinyl chloride metabolites and closely related compounds to rats shows that chloroacetaldehyde and S -(carboxymethyl)cysteine, but not chloroacetic acid, lie on a pathway or pathways connecting vinyl chloride with thiodiglycollic acid.

TL;DR: It is concluded that the major intracellular binders of CPZ and related drugs are the nonpolar moieties of membrane phospholipids, whereby hydrophobic interactions are mainly involved.

TL;DR: Results suggested that at the dose level employed Cd regulated the biosynthesis of metallothionein in the liver at the transcriptional level and in the kidney at the translational level.

TL;DR: Some of the biochemical changes in rat kidney following the administration of mercuric chloride have been determined and the change in the pattern of urinary enzyme excertion closely paralleled the ultrastructural changes in the tubular cells.

TL;DR: Findings suggest that the photosensitization of the skin observed in patients treated with chlorpromazine might be due to DNA damage.

TL;DR: The extended life span of the cultures appeared due to prolonged survival of cells and not to increased growth rate since RA inhibited the rate of cellular proliferation, which normally follows cellular maturation during the first two weeks in culture.

TL;DR: The general pattern of the results suggests that phosphotriesters are not excised by cellular repair systems and are instead formed in the DNA of lung, liver, kidney, spleen and thymus.

TL;DR: Several other minor methylated products were found in liver and intestinal DNA of rats treated with DMN or MNU, and two of these products are believed to be N3-methylthymidine and O6-methyldeoxyguanosine.

TL;DR: Mitochondrial DNA damaged by carcinogens was not repaired during 4-20 h of post-treatment incubation of the cells and incorporation of labeled thymidine into the closed circular mitochondrial DNA, decreased by the treatment of cells with carcinogens, recovered during post- treatment incubation.

TL;DR: Methotrexate treatment of tumour-bearing mice, conjunction with purine/pyrimidine protection, can be more effective than conventional metotrexate/folinic acid treatment.

TL;DR: The inhibition of skin tumor initiation by 7,8-BF and 5,6-BF appears to be partially related to its ability to inhibit the formation of electrophilic intermediates.

TL;DR: The O6-methylguanine/7-methyl guanine ratio was approx.

TL;DR: Equilibrium dialysis studies indicate that Pt(en)Cl2 binds reversibly to DNA to a saturation value of 0.57 Pt: P, which is consistent with the platinum being bound both monofunctionally and bifunctionally.

TL;DR: The results obtained do not contradict the hypothesis that O6-alkylation of guanine in DNA is a critical event in the initiation of tumour induction by alkylating agents, however, the location of tumours produced in mice does not seem to depend solely on the formation and persistence of O6 -alkylguanines in DNA.

TL;DR: The results showed a good correlation between the responses obtained for the three tests by the different compounds; thus, the toxic potency and the capacity of inhibiting transcription and translation should be directed by a common chemical structure.