Showing papers in "Chemico-Biological Interactions in 1995"

TL;DR: Nitric oxide at concentrations as low as 3 nM is expected to compete efficiently for superoxide near the surface of endothelial cells, based on competition kinetics.

TL;DR: The new SOD bands are possibly oxidized forms of this enzyme and can be considered as useful early biomarkers of oxidative stress due to transition metals or organic xenobiotics.

TL;DR: RNase protection assays demonstrated that in man each FMO gene displays a distinct developmental and tissue-specific pattern of expression.

TL;DR: The phototoxicity of BaP is found to be highly phototoxic while quinones that included menadione, danthron, phenanthrene-quinone and hydroquinone were not, and only the green algae almost completely metabolized BaP to dihydrodiols, indicating that algae are important in their ability to degrade PAHs.

TL;DR: Iron and copper ions mediate generation of reactive oxygen radicals from O2 and H2O2 by the Fenton reaction: these radicals are capable of damaging DNA and metallothionein may protect DNA from damage by sequestering copper and preventing its participation in redox reactions.

TL;DR: Analysis of rate constants affected by protonated lipophilic amines indicates that these allosteric effectors apparently modify enzyme structure so as to affect two or more rate constants and, depending on the nature and concentration of the xenobiotic substrate, protonate amines can either stimulate or inhibit catalytic activity.

TL;DR: Several DNA-adducts, similar to those formed in mouse kidney after OTA treatment, were detected in monkey kidney cells, which make Vero cells suitable for genotoxic and cytotoxic studies in relation to the metabolism of nephrotoxic xenobiotics such as OTA.

TL;DR: Data is reported on the kinetics of the reactions, the stability of the adducts at physiological pH, product yields, UV-spectroscopic data at different pH values, and the synthesis, isolation and structural characterization by FAB/MS and NMR of the stableadducts of acetaldehyde with dGuo.

TL;DR: Comparison of the effects on in vitro cytotoxicity with in vivo antitumor and antimetastatic action points out that these compounds reduce metastasis formation by a mechanism unrelated to a direct tumor cell cytot toxicity.

TL;DR: The above results indicate that through a copper-redox cycling mechanism the copper-mediated oxidation of HQ generates reactive oxygen species which may participate in DNA damage.

TL;DR: The data in hand point to a new trans platinum antitumour complex with a mechanism of action different from that of cis-DDP and classical analogues.

TL;DR: In this paper, the authors developed procedures for quantification of sulfoxide enantiomers and tertiary amine N-oxide diastereomer metabolites arising from the action of the adult human liver and other flavin-containing monooxygenases (FMOs).

TL;DR: A potential mechanism for neurotoxicity of artemisinin and its derivatives that involves the endoperoxide bridge is proposed which is also known to be necessary for their antimalarial action.

TL;DR: The hypothesis that 4HA was more readily converted to the reactive intermediate than TNT was supported by the increased levels of covalent adduct formation when [14C]4HA was incubated directly with liver microsomes, and the initial reduction of the nitro group can be catalyzed by NADPH cytochrome P450 reductase alone but cyto Chrome P450 is needed in the reduction ofThe hydroxylamine to the amine

TL;DR: Data obtained, from the inhibition of oxygen consumption by rat liver mitochondria, demonstrated that all of the twenty acetogenins tested are active with IC50 values in the range of 15-800 nM/mg protein, which indicates complete understanding of the utility and potential of this new group of very potent compounds.

TL;DR: The radical-scavenging ability of BVIT and VLC did not correlate with their effects on microsomal lipid peroxidation, and the stimulation of lipid per oxidation by thiamin, pyridoxine and carnitine suggests that supplementation of large amounts of these compounds may not be desirable.

TL;DR: Elevated amounts of modified DNA bases were found in most cancerous tissues when compared to the controls, and the association of the modified bases with the processes of aging and carcinogenesis deserves further investigation.

TL;DR: 3-ring PAHs did not competitively bind to the mouse hepatic cytosolic aryl hydrocarbon (Ah) receptor suggesting that 3-ringPAHs are a new class of Cyp1a-2 inducers which do not act through the Ah receptor.

TL;DR: The results of these studies indicate that both the In and As moieties of InAs are biologically active following InAs exposure and that the enzymes in the heme pathway, such as ALAD, may have great utility as markers of exposure/toxicity for these agents.

TL;DR: The results suggest that liver injury resulting from insufficient respiration involves reductive stress which releases intracellular Fe, converts xanthine dehydrogenase toxanthine oxidase and causes mitochondrial oxygen activation, and the cell's antioxidant defences are compromised and ATP catabolism contributes to oxygen activation.

TL;DR: Although the activities of antioxidant and phase II enzymes were elevated by both GTP and phenolic metabolites of benzene, GTP counteracted the lowering GSH caused by phenolic molecules of Benzene in rat liver, suggesting that GTP-phenolic fractions are antagonistic in their response to AOS, especially hydroxyl radical.

TL;DR: The results demonstrate that, despite their pentavalent oxidation state, these arsenic species are not analogs for phosphate, and that, over a 24 h incubation period, the reduction of As(V) to As(III) may account for 30% of the total As in rabbit erythrocytes.

TL;DR: The metabolism and distribution of a single oral dose of 25 mumol 14C-labelled 3,3',4,4'-tetrachlorobiphenyl (14C-TCB) were investigated in pregnant female Wistar rats and their fetuses and hydroxylated metabolites of polychlorinated biphenyls may play a role in the development toxicity of these compounds.

TL;DR: There may be a threshold cytotoxicity level for QMs related to their reactivity which may affect the relative toxicities of 4-alkyl-2-methoxyphenols.

TL;DR: It is suggested that the 3-MeSO2 derivatives studied are possibly potent phenobarbital-like inducers of microsomal drug-metabolizing enzymes by the parent PCB congeners.

TL;DR: T tertbutylhydroperoxide was found to induce a specific alteration of the skeletal network at the horizontal junction sites involving spectrin, actin, and protein 4.1 and thus to modify the cytoskeletal assembly, consistent with the hypothesis that oxidative stress plays a key role in the haemolytic process.

TL;DR: The presence of AcMDA in urine and as a hemoglobin adduct indicates that MDA was bioavailable after MDI exposure and may contribute significantly to the carciongenic potential of MDI, since MDA has been shown to be carcinogenic in animals.

TL;DR: DNA breaking was inhibited by hydrogen donors butyl hydroxyanisole and ethanol, thiol compounds L-cysteine and 2-mercaptoethanol, and spin-trapping agents DMPO and PBN, indicating the direct contribution of the carbon-centered radical to the breaking.

TL;DR: Data suggest that none of these agents alone would be successful antivesicant agents and different mechanisms are involved in production of HD-induced dark basal cells, microvesicles and the vascular response; unfortunately, blocking of the cellular toxicity as evidenced by dark basal cell formation did not prevent vesication, suggesting that other mechanisms must be operative and that there is a multistep, biochemical process that leads to a final lesion.

TL;DR: FMOs may also play a role in the in vivo metabolism of endogenous homocysteine S-conjugates, since S-benzyl-L-cysteine can be considered a model for these compounds.