研究者業績
基本情報
研究分野
1論文
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NEUROSCIENCE RESEARCH 68 E348-E348 2010年 査読有り
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JOURNAL OF MASS SPECTROMETRY 41(6) 810-814 2006年6月 査読有りThe Aconitum species (Ranunculaceae) are widely distributed in northern Asia and North America. Their roots are popularly used in herbal medicines in China and Japan. Many cases of accidental, suicidal and homicidal intoxication with this plant have been reported; some of these were fatal because the toxicity of Aconitum is very high. It is thus important to detect and quantify Aconitum alkaloids in body fluids, with high sensitivity. We have developed a simple and sensitive method for measuring four kinds of Aconitum alkaloids (aconitine, hypaconitine, jesaconitine and mesaconitine) by LC/electrospray (ESI)-time-of-flight (TOF)-MS. For all of them, only molecular ions were observed at an orifice voltage of 75 V; at 135 V, base peaks corresponding to [M - 60 + H](+) ions were observed. These four compounds and methyllycaconitine (internal standard) in human plasma samples were purified by solid-phase extraction. The four extracted compounds were completely separated in mass chromatograms; the calibration curves showed good linearity in the range 10-300 ng/ml, and the detection limits were estimated to be 0.2-0.5 ng/ml. Using our method, we also determined the amounts of these compounds in tuber samples. The present method is applicable in clinical and forensic toxicology. Copyright (c) 2006 John Wiley & Sons, Ltd.
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Japanese Journal of Forensic Toxicology 23(1) 37-40 2005年We have developed a simple and sensitive method for determining acetonitrile and propionitrile in human whole blood using capillary gas chromatography (GC) with cryogenic oven trapping. After heating 0.5 ml of a whole blood sample containing both nitriles and 0.5 ml of distilled water in a 7-ml vial at 75°C for 15 min, 5 ml of the headspace vapor was drawn into a 10-ml syringe and injected to GC with a flame thermionic detector. A sharp peak was obtained for acetonitrile at -10°C of the initial oven temperature. The extraction efficiencies for acetonitrile and propionitrile were 0.27 and 0.40%, respectively. For quantitation of acetonitrile, propionitrile was used as internal standard, and vise versa. The calibration curves for both compounds gave good linearity in the range of 0.2-6 μg/ml whole blood. The detection limits (signal to noise ratio = 3) were 0.05 μg/ml for acetonitrile and 0.01 μg/ml for propionitrile. The coefficients of intra-day variations were 1.0% at 0.4 μg/ml and 1.7% at 2 μg/ml for acetonitrile 7.1 % at 0.4 μg/ml and 1.0% at 2 μg/ml for propionitrile. This method can be applicable for determining these nitriles in whole blood samples in acute and chronic intoxication cases. ©2005 Japanese Association of Forensic Toxicology. All rights reserved.
MISC
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LEGAL MEDICINE 13(4) 205-209 2011年7月DNA methylation in gene promoter regions influences gene expression. Circadian clock genes play an important role in the formation of a biological clock and aberrant methylation of these genes contributes to several disorders. In this study, we examined forensic autopsy specimens to determine whether DNA methylation status in the promoter regions of nine circadian clock genes (Per1, Per2, Per3, Cry1, Cry2, Bmal1, Clock, Tim, and Ck1e) is related to a change in acquired diathesis and/or causes of death. Methylation-specific PCR and direct sequencing methods revealed that the promoters of Per1, Cry2, Bmal1, Clock, and Ck1e were unmethylated in all the forensic autopsy specimens, while the promoters of Per2, Per3, Cry1, and Tim were partially methylated. Methylation status varied between individuals and between tissues in the same patient. A detailed analysis of methylation patterns in the Cry1 promoter region revealed that the patterns also varied between individuals and the Cry1 promoter had highly methylated patterns in two cases that had been exposed to methamphetamine. These results suggest that the methylation status of clock gene promoters varies between individuals. Methamphetamine use may influence methylation in the Cry1 gene promoter region and disturb circadian rhythmicity. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
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FORENSIC TOXICOLOGY 28(2) 110-114 2010年7月 査読有りA number of reports are available in the literature that describe liquid chromatography-mass spectrometry (LC-MS) and LC-tandem mass spectrometry (LC-MS-MS) analysis of amanitins, very toxic mushroom toxins, in biological samples. However, the extractive pretreatment methods and LC separation column materials vary remarkably according to the different reports. This communication presents a very simple and sufficiently sensitive method for LC-MS analysis of amanitins. A plasma sample was diluted with distilled water and buffer solution, and applied to a Discovery DSC 18 column (500 mg packing material), followed by washing with distilled water and elution with methanol. The extract, after evaporation and reconstitution in mobile phase solution, was subjected to LC-MS analysis with a conventional octadecyl LC separation column. The selected ion monitoring of alpha-amanitin and beta-amanitin at m/z 919-921 and m/z 920-922, respectively, gave symmetrical peaks and good separation of both amanitin peaks. Using an external calibration method, linearity, detection limits, recovery rates, and precision were tested; they were all satisfactory. To our knowledge, the present method gives the simplest LC-MS analysis for amanitins among those so far reported. We recommend the method for use in actual forensic and clinical toxicological analysis of amanitins in biological samples.
講演・口頭発表等
1所属学協会
1共同研究・競争的資金等の研究課題
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日本学術振興会 科学研究費助成事業 2014年4月 - 2018年3月
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日本学術振興会 科学研究費助成事業 2008年 - 2010年
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日本学術振興会 科学研究費助成事業 2006年 - 2009年
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日本学術振興会 科学研究費助成事業 2005年 - 2007年
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日本学術振興会 科学研究費助成事業 2003年 - 2005年
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日本学術振興会 科学研究費助成事業 2001年 - 2003年
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日本学術振興会 科学研究費助成事業 1995年 - 1996年
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日本学術振興会 科学研究費助成事業 1994年 - 1994年
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日本学術振興会 科学研究費助成事業 1990年 - 1992年