國家衛生研究院 NHRI:Item 3990099045/2480

NHRI > National Institute of Environmental Health Sciences > Louis W. Chang(1999-2009) > Periodical Articles > Item 3990099045/2480

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Title:	Simultaneous determination of N-7-alkylguanines in DNA by isotope-dilution LC-tandem MS coupled with automated solid-phase extraction and its application to a small fish model
Authors:	Chao, MR;Wang, CJ;Yen, CC;Yang, HH;Lu, YC;Chang, LW;Hu, CW
Contributors:	Division of Environmental Health and Occupational Medicine
Abstract:	In the present study, we report the development of a sensitive and selective assay based on LC (liquid chromatography)MS/MS (tandem MS) to simultaneously measure N7-MeG (N-7- methylguanine) and N7-EtG (N-7-ethylguanine) in DNA hydrolysates. With the use of isotope internal standards (N-15(5)-N7-MeG and N-15(5)-N7-EtG) and on-line SPE (solid-phase extraction), the detection limit of this method was estimated as 0.42 fmol and 0.17 fmol for N7-MeG and N7-EtG respectively. The high sensitivity achieved here makes this method applicable to small experimental animals. This method was applied to measure N-7-alkylguanines in liver DNA from mosquito fish (Gambusia affinis) that were exposed to NDMA (N-nitrosodimethylamine) and NDEA (N-nitrosodiethylamine) alone or their combination over a wide range of concentrations (1-100 mg/l). Results showed that the background level of N7-MeG in liver of control fish was 7.89 +/- 1.38 mu mol/mol of guanine, while N7-EtG was detectable in most of the control fish with a range of 0.05-0.19 mu mol/mol of guanine. N7-MeG and N7-EtG were significantly induced by NDMA and NDEA respectively, at a concentration as low as 1 mg/l and increased in a dose-dependent manner. Taken together, this LC-MS/MS assay provides the sensitivity and high throughput required to evaluate the extent of alkylated DNA lesions in small animal models of cancer induced by alkylating agents.
Keywords:	Biochemistry & Molecular Biology
Date:	2007-03-15
Relation:	Biochemical Journal. 2007 Mar;402(Pt. 3):483-490.
Link to:	http://dx.doi.org/10.1042/BJ20061447
JIF/Ranking 2023:	http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=NHRI&SrcApp=NHRI_IR&KeyISSN=0264-6021&DestApp=IC2JCR
Cited Times(WOS):	https://www.webofscience.com/wos/woscc/full-record/WOS:000244941400008
Cited Times(Scopus):	http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=33947200792
Appears in Collections:	[Louis W. Chang(1999-2009)] Periodical Articles

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