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K Urano

Publications and source records attributed to K Urano.

49 records · Page 3Linked to original sources
PubMed1988

Method for evaluating mutagenicity of water. I. A new method of preparing samples for mutagenicity test.

A sample preparation method for a convenient and quantitative mutagenicity test of water was developed using two new superior resinous adsorbents. One, CSP800, is a small particle size and highly porous polystyrene resin, and the other, CHPA25, is a small particle size and highly porous anion-exchange resin. CSP800 adsorbed more nonionic compounds from water than conventional resins, and CHPA25 adsorbed anionic compounds not adsorbed by conventional resins. Sample water (10 l) at pH 5 was fed at 550 ml h-1 into two columns in series, one containing 5 ml of CSP800 and the other 2 ml of CHPA25. The adsorbed substances were subsequently desorbed by DMSO from CSP800 and by 4 N NaNO3 from CHPA25, at 10 ml h-1. Various organic substances, which were measured by different indices such as total trihalomethanes (THM), total organic halogen (TOX) and the absorbence at 260 nm, could be recovered by this method much more efficiently and conveniently than by conventional methods.

Chromatography, Ion Exchange↗
PubMed1988

Method for evaluating mutagenicity of water. II. Conditions for applying new sample preparation method to the Ames test.

Conditions for the application of a new sample preparation method developed in a previous study using the small particle size and highly porous polystyrene and anion-exchange resins CSP800 and CHPA25 were investigated. The desorbing solvents DMSO and 4 N NaNO3 (0.5 ml), corresponding to 11 of water sample, could be dosed on a plate for the mutagenicity test, the Ames test. It was confirmed that trace impurities from the resins were not mutagenic. The mutagenicity of several drinking water samples was determined by this new method and evaluated quantitatively by converting to the concentrations of the standard mutagens, 4-nitroquinoline-1-oxide and 2-aminoanthracene, without S9 and with S9 respectively. Furthermore, the mutagenicity of the nonionic pollutants adsorbed on CSP800 and that of the anionic pollutants adsorbed on CHPA25 could be evaluated separately.

Dose-Response Relationship, Drug↗
PubMedDate not supplied

Convenient dioxin measuring method using an efficient sampling train, an efficient HPLC system and a highly sensitive HRGC/LRMS with a PTV injector.

An efficient sampling method for dioxins from flue gas, an efficient automatic purification and fractionation method by a new HPLC system using a sulfuric acid-silica/silica column, a Nitro column and a PGC column, and sensitive determination method by an economical HRGC/LRMS using a programmable temperature vaporization (PTV) injector were developed. It was confirmed that the dioxins could be easily collected by the proposed simple sampling train consisting of only two bottles, and the extracted sample could be purified sufficiently and separated as mono-ortho PCBs, non-ortho PCBs and PCDDs/PCDFs completely with the proposed HPLC system. The peak areas of GC/MS were increased linearly with the injection volume up to 40 microl by the PTV technique, and the sensitivity could be increased to 20 times higher than usual. This convenient measuring method can drastically reduce operation time, consumption of hazardous solvent and cost.

Air Pollutants↗
PubMedDate not supplied

Overexpression of human H-ras transgene is responsible for tumors induced by chemical carcinogens in mice.

Level of human prototype H-ras transgene expression in tumors induced by chemical carcinogens (N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea) was analyzed in human H-ras transgenic mice (CB6F1-TgrasH2 Jic mice). All forestomach tumors examined revealed about 2-fold overexpression of the human H-ras transgene with or without point mutation at codon 12 or codon 61. However, endogenous mouse H- and K-ras genes exhibited neither point mutation nor overexpression. These results suggested that increased levels of ras gene products in the cell played an important role in facilitating chemical carcinogenesis in transgenic mice.

Animals↗