Showing papers in "Chemico-Biological Interactions in 1994"

TL;DR: This work has shown that the antioxidant-mediated activation of AP-1 relies on the de novo synthesis of c-fos and c-jun mRNAs, and SRE binding factors can be considered as primary antioxidant response factors, whileAP-1 itself is a secondary response factor.

TL;DR: Reduced intermediates of molecular oxygen, such as superoxide and hydrogen peroxide, are ubiquitous inorganic products of normal aerobic metabolism, but most cells require antioxidant protection against excessive production of these intermediates.

TL;DR: The role of reduced glutathione in the metabolism of arsenic is consistent with the previously described effects of this agent on the organismic toxicity of arsenic.

TL;DR: Sulfation of the phenolic hydroxyl group blocks the ORD of T4, while it strongly stimulates the IRD of both T4 and T3, indicating that sulfation is an important step in the irreversible inactivation of thyroid hormone.

TL;DR: It is now time to evaluate in humans the beneficial effect of antioxidants, and the more promising candidates for presenting synergistic effects when associated with N-acetyl cysteine seem to be beta-carotene, selenium and zinc.

TL;DR: Selenium deficiency is common in HIV positive patients as documented by low plasma and red blood cell levels of selenium, diminished activity of glutathione peroxidase, and low cardiac seleniam levels in AIDS hearts.

TL;DR: Little or no clear similarity was observed between the primary structures of enzymes N-sulfating aminosugars and those sulfating hydrophobic chemicals such as phenols, alcohols or amines, indicating that both types of enzymes diverged early in their evolutionary history.

TL;DR: Tyrosylprotein sulfotransferase has been purified and its substrate specificity characterized, and has been shown to be important for protein-protein interactions occurring during the intracellular transport of proteins and upon their secretion.

TL;DR: DNA was extracted from the white blood cells of human blood exposed to 131 microM sulfur mustard in vitro and shown to contain 470 pmol of 7-(2-hydroxyethylthio-ethyl) guanine per mg of DNA, demonstrating the applicability of this method to biological samples.

TL;DR: The involvement of the alcohol-inducible cytochrome P450 2E1 in the hepatoprotective mechanism of the plant flavonoid extract silymarin, and its main active component silybin, was investigated in isolated hepatocytes, and it is suggested that the antioxidant and free radical scavenging properties may account for most of the therapeutic effect of these compounds.

TL;DR: The estimates presented, however, do not invalidate arguments for a possible role of superoxide anions in intra- or pericellular signalling phenomena, and cross-talk between NO.- and O2-.-dependent signal routes is unlikely to be a relevant process under the conditions which prevail in the vascular system.

TL;DR: Initial observations on the effects of selenium supplementation in HIV-infected patients indicate that seenium causes symptomatic improvements and possibly slows the course of the disease.

TL;DR: Immunocytochemical studies in adult rat brain preparations with a polyclonal antibody that cross-reacts with MT-I and MT-II indicated that immunostaining was always nuclear in glial cells, whereas in neurons it was nuclear in the cerebral cortex, hippocampus and the granular layer of the cerebellum, and nuclear plus cytoplasmic in Purkinje cells in the brain stem.

TL;DR: It is shown that enzymatic sulfonation of members of several classes of proximate carcinogens containing C- or N-hydroxy groups converts them to electrophilic, mutagenic, and carcinogenic sulfuric acid ester metabolites in mouse liver.

TL;DR: The relevance of acyl-CoA accretion to human pathophysiology has now been well established, and identification of the relevant mechanism of toxicity can allow implementation of strategies to minimize the metabolic injury.

TL;DR: It is concluded that delta 4-VPA undergoes metabolic activation by both microsomal cytochrome P-450-dependent and mitochondrial coenzyme A-dependent processes, and that the resulting electrophilic intermediates, which are trapped in part by GSH, may mediate the hepatotoxic effects of this compound.

TL;DR: Three sulfotransferases catalysing the metabolic activation of potent carcinogenic polycyclic arylmethanols were purified from female Sprague-Dawley (SD) rat liver cytosol without loss of their enzyme activities in the presence of Tween 20 used for preventing the enzymes from aggregation during purification and identified as HSTs.

TL;DR: It was found that electron donating groups increased the rate of glucuronide conjugation, consistent with nucleophilic attack of the C-1 carbon of the UDP-glucuronic acid (UDPGA) by an SN2 mechanism, the first direct evidence for aSN2 mechanism in UDPGT catalysis.

TL;DR: Data from isolated rat hepatocytes indicate that other xenobiotics can modulate the formation and hydrolysis of ibuprofenyl-CoA by influencing inversion pathways, non-inversion pathways or both and accentuate inter-individual variability in response to 2-aryl-propionic acids.

TL;DR: Pharmacogenetic studies of ST enzymes in humans demonstrated that TS and TL PST activities in the human platelet are regulated by separate, common genetic polymorphisms.

TL;DR: 1-Hydroxymethylpyrene, 9-hydroxymethylanthracene and 6- Hydroxysteroid sulphotransferase a, which was stably expressed in Chinese hamster V79 cells, showed enhanced cytotoxicity in V79 rSTa-1 and V79r STa-2 cells, as compared with sulphotranferase-deficient control cells.

TL;DR: Sulfation is a major detoxication mechanism for endogenous compounds and xenobiotics performed by a family of sulfotransferase isoenzymes and the way in which endogenous and exogenous factors are able to influence their activity and expression will provide the information necessary to develop novel therapeutic strategies.

TL;DR: Findings suggest that VPA, which is an anticonvulsive drug frequently prescribed for the management of various seizure disorders, should not be recommended for treatment of epilepsy or other related illnesses in HIV-positive individuals.

TL;DR: The functional antioxidant activities of plant metabolites are illustrated and the use of these synergistic antioxidants from plants are proposed as a mechanism by which viral replication and cell killing in HIV infection can be inhibited.

TL;DR: Hydroxylation of meso-methyl groups with subsequent formation of reactive benzylic esters bearing a good leaving group (e.g. sulfate) was proposed as a possible biochemical mechanism of activation and tumorigenicity of methyl-substituted polycyclic aromatic hydrocarbons (PAHs).

TL;DR: Myeloperoxidase-dependent degradation of hyaluronic acid is inhibited by superoxide dismutase, desferrioxamine, iodide ion, bromide ions, mannitol, histidine and various antiinflammatory agents.

TL;DR: It is demonstrated that tissue and blood levels of UQ can be increased by exposure to appropriate chemical agents without elevating the concentration of cholesterol.

TL;DR: The vectorial transport of xenobiotics across the hepatocyte is mediated by various transport and transfer proteins that differ in ligand specificity and function, which will significantly advance the understanding of processes involved in xenobiotic toxicity and acquired resistance to chemical toxicity.

TL;DR: A series of halogenated propanes and propenes were studied for mutagenic effects in Salmonella typhimurium TA100 in the absence or presence of NADPH plus liver microsomes from phenobarbital-induced rats as an exogenous metabolism system to propose paths for the formation of genotoxic metabolites.

TL;DR: Free PM was detected in all spectra indicating that degradation of 4-GSCP gives rise to PM, the ultimate cytotoxic metabolite of CP, 4- GSCP therefore appears an important pool of phosphoramide mustard, which in turn can be deactivated by glutathione.