کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5860471 1133187 2014 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Noninvasive measurement of smoking-associated N3-ethyladenine and N7-ethylguanine in human salivary DNA by stable isotope dilution nanoflow liquid chromatography-nanospray ionization tandem mass spectrometry
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم محیط زیست بهداشت، سم شناسی و جهش زایی
پیش نمایش صفحه اول مقاله
Noninvasive measurement of smoking-associated N3-ethyladenine and N7-ethylguanine in human salivary DNA by stable isotope dilution nanoflow liquid chromatography-nanospray ionization tandem mass spectrometry
چکیده انگلیسی


- Simultaneous quantification of ethylpurines in salivary DNA by nanoLC-NSI/MS/MS.
- Only 20 μg of DNA isolated from about 3 mL of saliva is needed.
- Levels of 7-ethylguanine were significantly higher in smokers than in nonsmokers.

Evidence showed that ethylating agents are contained in cigarette smoke, which damage DNA producing ethylated DNA adducts, including N3-ethyladenine (3-EtAde) and N7-ethylguanine (7-EtGua). These two ethylpurines can be depurinated spontaneously and be repaired by enzymes and they have been detected in human urine. In this study, a highly specific and sensitive assay based on stable isotope dilution nanoflow liquid chromatography nanospray ionization tandem mass spectrometry (nanoLC-NSI/MS/MS) was used to measure 3-EtAde and 7-EtGua in human salivary DNA. These ethylpurines were released from DNA by neutral thermal hydrolysis and then enriched by a solid-phase extraction column before nanoLC-NSI/MS/MS analysis. The detection limits (S/N ≥ 3) of 3-EtA and 7-EtG were 15 fg (92 amol) and 10 fg (56 amol), respectively, injected on-column. The lower quantification limits of 3-EtAde and 7-EtGua were both 100 fg, i.e. 620 and 560 amol, respectively, corresponding to 9.4 and 8.6 adducts in 109 normal nucleotides, respectively, starting with as little as 20 μg of DNA isolated from an average of 3 mL of saliva. The mean (±SD) levels of 3-EtAde in 15 smokers and 15 nonsmokers were 12.6 ± 7.0 and 9.7 ± 5.3 in 108 normal nucleotides, respectively, while those of 7-EtGua were 14.1 ± 8.2 and 3.8 ± 2.8 in 108 normal nucleotides in smokers and nonsmokers, respectively. Levels of 7-EtGua, but not 3-EtAde, were statistically significantly higher in smokers than in nonsmokers (p < 0.0001). Furthermore, salivary 7-EtGua levels are significantly correlated with the number of cigarettes smoked per day as well as with the smoking index. This highly specific and sensitive stable isotope dilution nanoLC-NSI/MS/MS assay might be feasible in measuring 7-EtGua in human salivary DNA as a noninvasive biomarker for DNA damage induced by cigarette smoking.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Toxicology Letters - Volume 225, Issue 1, 10 February 2014, Pages 27-33
نویسندگان
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