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C. J. Dooley - One of the best experts on this subject based on the ideXlab platform.
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The presence of dimethyl- and diethyl-nitrosamines in deionized water
Food and Cosmetics Toxicology, 2005Co-Authors: Walter Fiddler, John W. Pensabene, Robert C. Doerr, C. J. DooleyAbstract:Summary Twenty seven of 42 samples of water exposed to deionizing resins contained from 0.03 to 0.34 ppb ( μ g/litre) Dimethylnitrosamine, as determined by gas-liquid chromatography combined with thermal energy analysis, a detection method claimed to be specific for nitrosamines. Twelve of these 27 samples, mainly from water obtained after resin regeneration, were confirmed as containing dimethyl-nitrosamine by gas-liquid chromatography-high resolution mass spectrometry. Two samples of water deionized at the Center, were confirmed as containing 0.33 and 0.83 diethylnitrosamine as well as the Dimethylnitrosamine. The origin of these nitrosamines is unknown at present.
Shinji Ogawa - One of the best experts on this subject based on the ideXlab platform.
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pathophysiological characteristics of Dimethylnitrosamine induced liver fibrosis in acute and chronic injury models a possible contribution of klf5 to fibrogenic responses
Digestive Diseases and Sciences, 2008Co-Authors: Fumihiro Ohara, Aisuke Nii, Yojiro Sakiyama, Megumi Tsuchiya, Shinji OgawaAbstract:Dimethylnitrosamine administration induces a rapid increase in collagen deposition with concomitant proliferation of hepatic stellate cells in rats. Here, we investigated the pathophysiological profiles of acute and chronic hepatic fibrosis states and attempted to determine the possible role of Kruppel-like factor-5 (KLF5) in this model. In acute study using a single drug injection, we observed a rapid transient increase of ALT and mRNA levels of KLF5 followed by increases in fibrosis-related genes. Repeated administration of Dimethylnitrosamine once a week caused early damage with severe fibrosis and sustained hepatocyte injury, while intermittent injections at 2-week intervals induced only modest fibrosis from 3 weeks. Weekly administration also induced profound upregulation of collagen I, α-smooth muscle actin, and KLF5 mRNA. In contrast, such continued augmentation was not observed after intermittent injections; KLF5 increased only after 3 weeks. These results suggested that Dimethylnitrosamine induced a rapid hepatic fibrogenic response with a possible participation of KLF5.
Thomas A. Grigliatti - One of the best experts on this subject based on the ideXlab platform.
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A rapid somatic genotoxicity assay in Drosophila melanogaster using multiple mutant mutagen-sensitive (mus) strains.
Mutagenesis, 1992Co-Authors: Daryl S. Henderson, Thomas A. GrigliattiAbstract:: Mutagen-sensitive (mus) mutations in Drosophila melanogaster render developing flies hypersensitive to the lethal effects of DNA-damaging agents. In principle, multiply mutant mus strains might then serve as sensitive in vivo indicators of a wide range of mutagens and genotoxic carcinogens. As a first step to evaluate that potential we characterized interactions between mus mutations in eight double mutants containing combinations of the second chromosomal mutations mus201D1, mus205B1, mus208B1, mus210B1 and mus211B1. We found that (i) all double mutants are fully viable in the absence of mutagen exposure, (ii) mus205B1 is epistatic to any other mus mutation with respect to methyl methanesulfonate (MMS) sensitivity, and (iii) in double mutants carrying any combination of mus201D1, mus210B1 or mus211B1, MMS sensitivity is increased in a synergistic manner. Based on those results, and on mutagen cross-sensitivity data of single mutants generated in previous studies, we constructed two triple mutant mus strains for use as testers in a simple genotoxicity assay. That assay measures the survival of DNA repair-deficient mus homozygotes relative to their repair-proficient heterozygous siblings. Those two classes of fly are easily distinguished from one another by their phenotypic markers. In addition, the heterozygotes serve as a relatively mutagen-insensitive internal control in all test vials. One tester strain (mus208B1 mus210B1 mus211B2) identified 11 of 12 chemical carcinogens as genotoxic (benzo[a]pyrene, cyclophosphamide, 1,2,3,4-diepoxybutane, diethylnitrosamine, Dimethylnitrosamine, ethyl methanesulfonate, formaldehyde, hexamethylphosphoramide, methyl methanesulfonate, methylnitrosourea and N-methyl-N'-nitro-N-nitrosoguanidine). Safrole and two noncarcinogens (benzo[e]pyrene and caprolactam) tested as nongenotoxic.(ABSTRACT TRUNCATED AT 250 WORDS)
Walter Fiddler - One of the best experts on this subject based on the ideXlab platform.
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The presence of dimethyl- and diethyl-nitrosamines in deionized water
Food and Cosmetics Toxicology, 2005Co-Authors: Walter Fiddler, John W. Pensabene, Robert C. Doerr, C. J. DooleyAbstract:Summary Twenty seven of 42 samples of water exposed to deionizing resins contained from 0.03 to 0.34 ppb ( μ g/litre) Dimethylnitrosamine, as determined by gas-liquid chromatography combined with thermal energy analysis, a detection method claimed to be specific for nitrosamines. Twelve of these 27 samples, mainly from water obtained after resin regeneration, were confirmed as containing dimethyl-nitrosamine by gas-liquid chromatography-high resolution mass spectrometry. Two samples of water deionized at the Center, were confirmed as containing 0.33 and 0.83 diethylnitrosamine as well as the Dimethylnitrosamine. The origin of these nitrosamines is unknown at present.
Fumihiro Ohara - One of the best experts on this subject based on the ideXlab platform.
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pathophysiological characteristics of Dimethylnitrosamine induced liver fibrosis in acute and chronic injury models a possible contribution of klf5 to fibrogenic responses
Digestive Diseases and Sciences, 2008Co-Authors: Fumihiro Ohara, Aisuke Nii, Yojiro Sakiyama, Megumi Tsuchiya, Shinji OgawaAbstract:Dimethylnitrosamine administration induces a rapid increase in collagen deposition with concomitant proliferation of hepatic stellate cells in rats. Here, we investigated the pathophysiological profiles of acute and chronic hepatic fibrosis states and attempted to determine the possible role of Kruppel-like factor-5 (KLF5) in this model. In acute study using a single drug injection, we observed a rapid transient increase of ALT and mRNA levels of KLF5 followed by increases in fibrosis-related genes. Repeated administration of Dimethylnitrosamine once a week caused early damage with severe fibrosis and sustained hepatocyte injury, while intermittent injections at 2-week intervals induced only modest fibrosis from 3 weeks. Weekly administration also induced profound upregulation of collagen I, α-smooth muscle actin, and KLF5 mRNA. In contrast, such continued augmentation was not observed after intermittent injections; KLF5 increased only after 3 weeks. These results suggested that Dimethylnitrosamine induced a rapid hepatic fibrogenic response with a possible participation of KLF5.