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Applied Optics Mar 1991A photothermal laser interferometric system is described that has sufficient sensitivity to allow the detection of the hydrazines: hydrazine, monomethylhydrazine, and...
A photothermal laser interferometric system is described that has sufficient sensitivity to allow the detection of the hydrazines: hydrazine, monomethylhydrazine, and unsymmetrical dimethyihydrazine at part per billion concentrations. A line tunable CO(2) laser excites the trace hydrazine molecules in one arm of a modified Jamin interferometer illuminated with a single frequency He-Ne laser. The CO(2) laser beam intersects one of the He-Ne beams in the interferometer at a small angle, so there is no interaction of the IR and visible laser beams at any optical components in the system. The system operates with computer control of interferometer alignment, CO(2) excitation laser tuning, and data acquisition.
PubMed: 20582056
DOI: 10.1364/AO.30.000756 -
Food and Chemical Toxicology : An... Jan 1991N-Methyl N-formlhydrazine (1), a component of the mushroom Gyromitra esculenta, is a carcinogen. Its mode of action, however, is poorly understood. To determine the...
N-Methyl N-formlhydrazine (1), a component of the mushroom Gyromitra esculenta, is a carcinogen. Its mode of action, however, is poorly understood. To determine the intermediates that may form during the metabolism of 1, we examined its oxidative chemistry, identified the products and inferred the intermediates on the basis of these products. The incubation of 1 with rat liver microsomes was also studied and the metabolites determined and quantified. Both the chemical and the microsome-mediated oxidation of 1 yielded formaldehyde and acetaldehyde. The formation of acetaldehyde requires (i) the oxidation of 1 to a diazenium ion (I) or diazene (II) and (ii) fragmentation of I/II to formyl and methyl radicals. It is suggested that these radical intermediates may be important in understanding and elucidating carcinogenesis by 1.
Topics: Acetaldehyde; Animals; Chromatography, Gas; Chromatography, High Pressure Liquid; Formaldehyde; Free Radicals; Imides; Microsomes, Liver; Monomethylhydrazine; Oxidation-Reduction; Rats
PubMed: 1999305
DOI: 10.1016/0278-6915(91)90062-c -
The Journal of Biological Chemistry Dec 1990Methylhydrazine oxidation promoted by horseradish peroxidase-H2O2 or ferricyanide led to the generation of high yields of methyl radicals and to the formation of...
Methylhydrazine oxidation promoted by horseradish peroxidase-H2O2 or ferricyanide led to the generation of high yields of methyl radicals and to the formation of 7-methylguanine and 8-methylguanine upon interaction with calf thymus DNA. Methyl radicals were identified by spin-trapping experiments with alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone and tert-nitrosobutane. The methylated guanine products were identified in the neutral hydrolysates of treated DNA by high pressure liquid chromatography (HPLC) analysis and spiking with authentic samples. The structure of 8-methylguanine, a product not previously reported in enzymatic systems, was confirmed by HPLC chromatography, UV absorbance, and mass spectrometry. The formation of 8-methylguanine suggests a possible role for carbon-centered radicals as DNA-alkylating agents.
Topics: Alkylation; DNA; Electron Spin Resonance Spectroscopy; Free Radicals; Guanine; Horseradish Peroxidase; Hydrolysis; Mass Spectrometry; Monomethylhydrazine; Oxidation-Reduction; Spectrophotometry, Ultraviolet
PubMed: 2176204
DOI: No ID Found -
Lipids Aug 1990Peroxidation of lipids produces carbonyl compounds; some of these, e.g., malonaldehyde and 4-hydroxynonenal, are genotoxic because of their reactivity with biological...
Peroxidation of lipids produces carbonyl compounds; some of these, e.g., malonaldehyde and 4-hydroxynonenal, are genotoxic because of their reactivity with biological nucleophiles. Analysis of the reactive carbonyl compounds is often difficult. The methylhydrazine method developed for malonaldehyde analysis was applied to simultaneously measure the products formed from linoleic acid, linolenic acid, arachidonic acid, and squalene upon ultraviolet-irradiation (UV-irradiation). The photoreaction products, saturated monocarbonyl, alpha,beta-unsaturated carbonyls, and beta-dicarbonyls, were derivatized with methylhydrazine to give hydrazones, pyrazolines, and pyrazoles, respectively. The derivatives were analyzed by gas chromatography and gas chromatography-mass spectrometry. Lipid peroxidation products identified included formaldehyde, acetaldehyde, acrolein, malonaldehyde, n-hexanal, and 4-hydroxy-2-nonenal. Malonaldehyde levels formed upon 4 hr of irradiation were 0.06 micrograms/mg from squalene, 2.4 micrograms/mg from linolenic acid, and 5.7 micrograms/mg from arachidonic acid. Significant levels of acrolein (2.5 micrograms/mg) and 4-hydroxy-2-nonenal (0.17 micrograms/mg) were also produced from arachidonic acid upon 4 hr irradiation.
Topics: Acetaldehyde; Acrolein; Aldehydes; Arachidonic Acid; Arachidonic Acids; Chromatography, Gas; Formaldehyde; Gas Chromatography-Mass Spectrometry; Linoleic Acid; Linoleic Acids; Linolenic Acids; Lipid Peroxidation; Lipids; Malondialdehyde; Monomethylhydrazine; Squalene; Ultraviolet Rays
PubMed: 2120528
DOI: 10.1007/BF02538089 -
Boletin de Estudios Medicos Y Biologicos 1990The placenta is a vascular organ within the uterus, connected to the fetus by the umbilical cord; it is the structure through which the fetus is nourished. In the rat...
The placenta is a vascular organ within the uterus, connected to the fetus by the umbilical cord; it is the structure through which the fetus is nourished. In the rat placenta, three regions can be identified: the decidua basalis, the basal zone, and the labyrinth. In the present work, doses of 4.2 mg/kg of Natulán (Roche), as used for human therapy, were administered orally to pregnant rats. The number of glycogenic cells from the basal zone of the placenta was increased, which allows us to suggest that Natulán causes an inhibition of glycolysis, by blocking the metabolism of the placenta, as proposed by Warburg.
Topics: Animals; Female; Glycolysis; Monomethylhydrazine; Placenta; Pregnancy; Procarbazine; Rats
PubMed: 2103745
DOI: No ID Found -
The Journal of Biological Chemistry Mar 1990The dissimilatory nitrite reductase, cytochrome cd1, from Pseudomonas aeruginosa (ATCC 19429) was irreversibly inactivated by methyl- or phenylhydrazine but was only...
The dissimilatory nitrite reductase, cytochrome cd1, from Pseudomonas aeruginosa (ATCC 19429) was irreversibly inactivated by methyl- or phenylhydrazine but was only reduced by hydrazine itself. The reaction required oxygen and several turnovers, approximately four, of the cytochrome acting to transfer reducing equivalents from phenylhydrazine to oxygen. The reaction with methyl- or phenylhydrazine altered the visible spectrum of the cytochrome. Bands characteristic of reduced heme c appeared plus new features that were not characteristic of either oxidized or reduced heme d1. Extraction of the heme from phenylhydrazine-treated cytochrome yielded a covalently modified form of the original heme d1. Visible, 1H NMR, and mass spectra were obtained on the purified modified heme and on the metal-free esterified derivative. The spectroscopic data indicate that the modification was the regiospecific substitution of the 5 meso-proton by a phenyl group.
Topics: Chromatography, Gel; Chromatography, High Pressure Liquid; Cytochromes; Electron Transport Complex IV; Hydrazines; Hydroquinones; Kinetics; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Monomethylhydrazine; Nitrite Reductases; Oxygen Consumption; Phenylhydrazines; Pseudomonas; Spectrophotometry
PubMed: 2155216
DOI: No ID Found -
Toxicology and Applied Pharmacology Feb 1990The effects of phenylhydrazine (PHZ) and monomethylhydrazine (MMH) on the deformability of human erythrocytes and ghosts in relation to Heinz body formation are... (Comparative Study)
Comparative Study
The effects of phenylhydrazine (PHZ) and monomethylhydrazine (MMH) on the deformability of human erythrocytes and ghosts in relation to Heinz body formation are investigated using the sensitive flow EPR (electron paramagnetic resonance) method. The decrease in deformability starts even before Heinz body formation is recognized and is enhanced with PHZ as Heinz bodies are attached on the inner surface of the membrane, but remains at a low level in MMH-treated cells in which Heinz bodies are formed mostly away from the membrane surface. Dithioerythritol recovers part of the lost deformability by MMH but has no effect in PHZ-treated cells or in the ghosts. The membrane fluidity measurements by 12-doxyl stearate indicate that there are two distinct modes of spin-label interaction in PHZ-treated cell membrane, the one corresponding to more immobilization gaining with the PHZ concentration, while MMH has only minor effects on fluidity. The motional freedom of membrane proteins probed with maleimide label shows that the membrane binding of hemoglobin denatured with PHZ causes more immobilization than that with MMH. These observations and Fe(III) EPR absorptions of the treated cells and ghosts are interpreted on the basis of the difference in reaction products (denatured hemoglobin) by the two reagents: the ones with PHZ preferentially bind to the membrane proteins, such as band 3, resulting in a perturbation of the membrane viscoelastic properties, while MMH-denatured hemoglobins remain mostly in the cytosol as Heinz bodies, or in the polymeric form contributing to the internal viscosity.
Topics: Cyclic N-Oxides; Dithiothreitol; Electron Spin Resonance Spectroscopy; Erythrocyte Deformability; Erythrocyte Membrane; Heinz Bodies; Hemoglobins; Humans; Membrane Fluidity; Methylhydrazines; Monomethylhydrazine; Phenylhydrazines; Protein Denaturation; Spin Labels
PubMed: 2154065
DOI: 10.1016/0041-008x(90)90021-l -
Free Radical Biology & Medicine 1989Isolated hepatocytes and liver microsomes incubated with monomethyl-1,1 dimethyl- and 1,2 dimethyl-hydrazines produced free radical intermediates which were detected by...
Isolated hepatocytes and liver microsomes incubated with monomethyl-1,1 dimethyl- and 1,2 dimethyl-hydrazines produced free radical intermediates which were detected by ESR spectroscopy by using 4-pyridyl-1-oxide-t-butyl nitrone (4-POBN) as spin trapping agent. The spectral features of the spin adducts derived from all three hydrazine derivatives corresponded to the values reported for the methyl free radical adduct of 4-POBN. In the microsomal preparations inhibitors of the mixed function oxidase system and the destruction of cytochrome P450 by pretreating the rats with CoCl2 all decreased the free radical formation. Methimazole, an inhibitor of FAD-containing monoxygenase system, similarly decreased the activation of 1,1 dimethyl-hydrazine, but not that of monomethyl- and 1,2 dimethyl-hydrazines. The addition to liver microsomes of physiological concentrations of glutathione (GSH) lowered by approx. 80% the intensities of the ESR signals. Consistently, incubation of isolated hepatocytes with methyl-hydrazines decreased the intracellular GSH content, suggesting that GSH can effectively scavenge the methyl free radicals. The results obtained suggest that methyl free radicals could be the alkylating species responsible for the toxic and/or carcinogenic effect of methyl-hydrazines.
Topics: Animals; Biotransformation; Cytochrome P-450 Enzyme Inhibitors; Dimethylhydrazines; Electron Spin Resonance Spectroscopy; Free Radicals; Glutathione; Liver; Male; Methylhydrazines; Microsomes, Liver; Mixed Function Oxygenases; Monomethylhydrazine; Nitrogen Oxides; Pyridines; Rats; Rats, Inbred Strains; Spin Labels
PubMed: 2536341
DOI: 10.1016/0891-5849(89)90152-4 -
Bulletin of Environmental Contamination... Dec 1988
Topics: Biodegradation, Environmental; Carbon Radioisotopes; Gram-Negative Aerobic Bacteria; Methylhydrazines; Monomethylhydrazine; Pseudomonas; Soil Microbiology; Soil Pollutants
PubMed: 3148345
DOI: 10.1007/BF02021046 -
Bulletin of Environmental Contamination... Sep 1988
Topics: Bacteria, Aerobic; Carbon Dioxide; Colorimetry; Fungi; Methylhydrazines; Monomethylhydrazine; Soil Microbiology
PubMed: 3146358
DOI: 10.1007/BF01688893