Analysis of (1) Glyoxal-Induced DNA Cross-Links in Human White Blood Cell DNA and (2) Etheno Adducts and 8-Hydroxy-2’-deoxyguanosine in Human Urine by Stable Isotope Dilution Liquid Chromatography-Nanospray Ionization Tandem Mass Spectrometry

• Main Authors: Ya-lan chang, 張雅嵐
• Other Authors: Chen, Hauh-Jyun Candy
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/57758824654267224051

碩士 === 國立中正大學 === 化學暨生物化學研究所 === 100 === There are many reactive chemicals in our living environment which could reactive with DNA forming DNA adducts. There are two parts in my thesis. In the first part, we developed a highly sensitive and specific quantitative assay for simultaneous detection and quantification of dG-gx-dA and dG-gx-dC cross-links by stable isotope dilution nanoflow liquid chromatography nanospray ionization tandem mass spectrometry (nanoLC-NSI/MS/MS) under the highly selective reaction monitoring (H-SRM) mode. Levels of dG-gx-dC and dG-gx-dA in human placenta DNA are 5.92 and 6.39 in 108 normal nucleotides, respectively. Levels of dG-gx-dC and dG-gx-dA are 1.44 ± 1.17 and 1.70 ± 1.08 in 108 normal nucleotides ,respectively, in 11 smokers’ white blood cell (WBC) DNA, and those in 9 nonsmokers’ WBC DNA are 0.81 ± 0.62 and 0.79 ± 0.85 in 108 normal nucleotides, respectively. Thus, it is clinically feasible using this highly sensitive assay to investigate the potential of these cross-links as low-invasive biomarkers for glyoxal-induced DNA damage and in disease development and prevention. In the second part, we developed a highly specific and sensitive method for simultaneous quantification of etheno DNA adducts: εAde, εCyt, 1,N2-εGua, and 8OHdG in human urine by stable isotope dilution capillary LC-NSI/MS/MS under the H-SRM mode. The urine concentration of εAde, εCyt, 1,N2-εGua, and 8OHdG are 52.2 ± 82.4, 21.2 ± 24.7, 76.6 ± 53.9 pg/mL and 2.82 ± 1.52 ng/mL in 4 smokers’ urine samples, respectively, and those in 8 nonsmokers’ urine samples are 40.8 ± 44.8, 55.6 ± 89.5, 69.6 ± 116.7 pg/mL and 2.64 ± 2.67 ng/mL, respectively. This capillary LC-NSI/MS/MS method provides a useful assay in measuring etheno and oxidative adducts as noninvasive biomarkers in cancer risk assessment.