Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and...Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and 1,7-dimethylxanthine(17X) and assess the activity of cytochrome P-450 CYP2A6.Methods The contents of five major metabolites of caffeine in the urine were determined by RP-HPLC method.Frequency distribution histogram was drawn by calculating the 17U/(AFMU+1X+1U+17X+17U) and then evaluated the activity of CYP2A6.Results The frequency distribution histograms of CYP2A6 approximately indicated three distinct groups,the cut of point is 0.23 between fast metabolizer and intermediate type.And the cut of point is 0.15 between slow metabolizer and intermediate type.Conclusion The method is simple and rapid,suitable for the determination of metabolites of caffeine in urine.The method can be used to assay the activity of CYP2A6.展开更多
目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2...目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2014年6月。使用Rev Man 5.3和Stata 11.2进行统计分析。结果共纳入7篇文献进入分析,文献质量评价结果显示纳入研究质量良好。一般资料结果显示,在东方人种中,CYP2A6＊1/＊1（W/W）频率平均为25.6%;CYP2A6＊4A,＊7,＊9,＊10存在一种突变（W/V）频率平均为48.8%,CYP2A6＊4A,＊7,＊9,＊10存在2种突变（V/V）频率平均为25.6%。Meta分析发现：1突变型V/V与野生型W/W及突变型W/V患者的S-1化疗敏感性差异有统计学意义,合并优势比（OR）为0.27（95%CI：0.14~0.51）;2野生型W/W与突变型W/V及V/V生存HR差异有统计学意义,合并HR值为1.71（95%CI：0.99~2.94）。结论 CYP2A6＊4A,＊7,＊9,＊10与晚期肿瘤患者S-1化疗获益存在一定关联性。但因为纳入研究的数量有限,需要有大样本、多变量的分析研究来进一步证实和完善本研究结果。展开更多
AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites ...AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites in 24 Chinese healthy volunteers. METHODS: 100 mg of caffeine was given to each subject as a probe drug and the urine samples of 0-12 h were collected. Urine samples were extracted with chloroform/isopropanol (9∶1, v/v) under acerbic environment (pH 3.5) and separated on a Hypersil BDS C18 column with gradient elution. The mobile phase was composed of phase A (acetonitrile) and phase B (10 mmol/L ammonium formate/formic acid (998/2, v/v) (pH 3.5) from 98/2 to 70/30, the detection wave length was 280 nm. CYP1A2 phenotype was calculated from the metabolite ratio of (AFMU+1X+1U)/17U, CYP2A6 from the ratio of 17U/(17U+17X+1U+1X+AFMU), NAT2 from the ratio of AFMU/(AFMU+1U+1X) and XO from the ratio of 1U/1X+1U. RESULTS: The calibration curves of AFMU, 1U, 1X, 17U, 17X, 137X were linear over the range of 1.25-160 μmol/L, yielding correlation of coefficients from 0.991 to 0.999. The LOD were 2.5 ng/mL for AFMU, 1X, 1U and 1 ng/mL for 17U, 17X, 137X. Recoveries for the analytes wereranged from 81%-94%, Intra-and Inter-day coefficients of variation were ranged from 2.56%-9.48% and 5.74%-10.91%, respectively. After logarithmic transformation of these metabolite ratios, phenotype of CYP1A2, CYP2A6, NAT2 were shown normal distribution, while the phenotype of XO was shown non-normal distribution with two subjects appearing with very low metabolic capacity. It was also found a negative association between the phenotype of CYP2A6 and CYP1A2 which might be explained by the fact that CYP2A6 plays an influential role in 17X metabolism. CONCLUSION: In brief, the experiment demonstrates an accurate, stable and replicable HPLC method for phenotyping of these enzymes in Chinese volunteers.展开更多
While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from t...While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from the three subjects, we discovered that the three subjects possessed the whole CYP2A6 gene deletion (CYP2A6*4C), a novel genetic polymorphism of the CYP2A6 gene. Genetically engineered Salmonella YG7108 cells expressing human CYP2A6 or CYP2E1 together with the NADPH-CYP reductase were established in our laboratory to compare the mutagen-producing capacity of these enzymes for various N-nitrosamines. We found that CYP2E1 was responsible for the metabolic activation of N-nitrosamines with relatively short alkyl chains, whereas CYP2A6 was involved in the metabolic activation of N-nitrosamines possessing relatively bulky alkyl chains such as a tobacco-specific nitrosamine, NNK, which has been known to cause lung tumor in rodents. Thus, to examine a hypothesis that individuals possessing the CYP2A6*4C have the reduced risk of lung cancer due to the lack of the capacity of the metabolic activation of certain carcinogens in tobacco smoke, a case-control study was performed.展开更多
目的分析西安汉族人群CYP2A6基因拷贝数多态性及其与吸烟行为的关联性。方法选取2021年9月—2023年6月在西安区域医学检验中心体检的西安汉族居民3500例为研究对象。根据受试者是否吸烟,将其分为吸烟组(2233例)和不吸烟组(1267例),根据...目的分析西安汉族人群CYP2A6基因拷贝数多态性及其与吸烟行为的关联性。方法选取2021年9月—2023年6月在西安区域医学检验中心体检的西安汉族居民3500例为研究对象。根据受试者是否吸烟,将其分为吸烟组(2233例)和不吸烟组(1267例),根据吸烟组受试者吸烟程度将其进一步分为轻度吸烟亚组(476例)和重度吸烟亚组(1757例)。采用TaqMan®Copy Number Assays试剂盒检测受试者CYP2A6基因拷贝数多态性。结果3500例受试者中,CYP2A6基因拷贝数为0者32例(0.91%),CYP2A6基因拷贝数为1拷贝者632例(18.06%),CYP2A6基因拷贝数为2拷贝者2737例(78.20%),CYP2A6基因拷贝数为≥3拷贝者99例(2.83%)。吸烟组CYP2A6基因拷贝数为0、1拷贝者占比低于不吸烟组,CYP2A6基因拷贝数为2拷贝、≥3拷贝者占比高于不吸烟组(P<0.05)。轻度吸烟亚组与重度吸烟亚组CYP2A6基因拷贝数多态性比较,差异无统计学意义(P>0.05)。结论西安汉族人群CYP2A6基因缺失率较高,达18.97%;西安汉族人群CYP2A6基因拷贝数多态性与吸烟行为可能存在关联,且CYP2A6基因缺失个体不易形成烟草依赖,而CYP2A6基因拷贝数多态性可能与吸烟程度不存在关联。展开更多
文摘Aim To establish a HPLC method for determining five major metabolites of caffeine in the urine,5-acetylamino-6-formylamino-3-methyluracil(AFMU),1-methylxanthine(1X),1-methyluric acid(1U),1,7-dimethyluric acid(17U) and 1,7-dimethylxanthine(17X) and assess the activity of cytochrome P-450 CYP2A6.Methods The contents of five major metabolites of caffeine in the urine were determined by RP-HPLC method.Frequency distribution histogram was drawn by calculating the 17U/(AFMU+1X+1U+17X+17U) and then evaluated the activity of CYP2A6.Results The frequency distribution histograms of CYP2A6 approximately indicated three distinct groups,the cut of point is 0.23 between fast metabolizer and intermediate type.And the cut of point is 0.15 between slow metabolizer and intermediate type.Conclusion The method is simple and rapid,suitable for the determination of metabolites of caffeine in urine.The method can be used to assay the activity of CYP2A6.
文摘目的运用系统回顾和Meta分析的方法评价CYP2A6基因多态性与S-1化疗获益的关系。方法检索Pubmed、CNKI、CBM和万方中文数据库,按照纳入和排除标准筛选关于CYP2A6基因与S-1化疗获益相关的病例对照研究或队列研究,检索时限为数据库建库至2014年6月。使用Rev Man 5.3和Stata 11.2进行统计分析。结果共纳入7篇文献进入分析,文献质量评价结果显示纳入研究质量良好。一般资料结果显示,在东方人种中,CYP2A6＊1/＊1（W/W）频率平均为25.6%;CYP2A6＊4A,＊7,＊9,＊10存在一种突变（W/V）频率平均为48.8%,CYP2A6＊4A,＊7,＊9,＊10存在2种突变（V/V）频率平均为25.6%。Meta分析发现：1突变型V/V与野生型W/W及突变型W/V患者的S-1化疗敏感性差异有统计学意义,合并优势比（OR）为0.27（95%CI：0.14~0.51）;2野生型W/W与突变型W/V及V/V生存HR差异有统计学意义,合并HR值为1.71（95%CI：0.99~2.94）。结论 CYP2A6＊4A,＊7,＊9,＊10与晚期肿瘤患者S-1化疗获益存在一定关联性。但因为纳入研究的数量有限,需要有大样本、多变量的分析研究来进一步证实和完善本研究结果。
文摘AIM: Caffeine metabolite ratios in urine can be used to evaluate the activity of CYP1A2, CYP2A6, NAT2 and XO in vivo. In this study, an HPLC method was developed to quantify the concentrations of caffeine metabolites in 24 Chinese healthy volunteers. METHODS: 100 mg of caffeine was given to each subject as a probe drug and the urine samples of 0-12 h were collected. Urine samples were extracted with chloroform/isopropanol (9∶1, v/v) under acerbic environment (pH 3.5) and separated on a Hypersil BDS C18 column with gradient elution. The mobile phase was composed of phase A (acetonitrile) and phase B (10 mmol/L ammonium formate/formic acid (998/2, v/v) (pH 3.5) from 98/2 to 70/30, the detection wave length was 280 nm. CYP1A2 phenotype was calculated from the metabolite ratio of (AFMU+1X+1U)/17U, CYP2A6 from the ratio of 17U/(17U+17X+1U+1X+AFMU), NAT2 from the ratio of AFMU/(AFMU+1U+1X) and XO from the ratio of 1U/1X+1U. RESULTS: The calibration curves of AFMU, 1U, 1X, 17U, 17X, 137X were linear over the range of 1.25-160 μmol/L, yielding correlation of coefficients from 0.991 to 0.999. The LOD were 2.5 ng/mL for AFMU, 1X, 1U and 1 ng/mL for 17U, 17X, 137X. Recoveries for the analytes wereranged from 81%-94%, Intra-and Inter-day coefficients of variation were ranged from 2.56%-9.48% and 5.74%-10.91%, respectively. After logarithmic transformation of these metabolite ratios, phenotype of CYP1A2, CYP2A6, NAT2 were shown normal distribution, while the phenotype of XO was shown non-normal distribution with two subjects appearing with very low metabolic capacity. It was also found a negative association between the phenotype of CYP2A6 and CYP1A2 which might be explained by the fact that CYP2A6 plays an influential role in 17X metabolism. CONCLUSION: In brief, the experiment demonstrates an accurate, stable and replicable HPLC method for phenotyping of these enzymes in Chinese volunteers.
文摘While we studied pharmacokinetics of SM-12502 which was under development as an anti-PAF agent, we found three subjects showing a slow metabolic phenotype in its pharmacokinetics. Analyzing the genes for CYP2A6 from the three subjects, we discovered that the three subjects possessed the whole CYP2A6 gene deletion (CYP2A6*4C), a novel genetic polymorphism of the CYP2A6 gene. Genetically engineered Salmonella YG7108 cells expressing human CYP2A6 or CYP2E1 together with the NADPH-CYP reductase were established in our laboratory to compare the mutagen-producing capacity of these enzymes for various N-nitrosamines. We found that CYP2E1 was responsible for the metabolic activation of N-nitrosamines with relatively short alkyl chains, whereas CYP2A6 was involved in the metabolic activation of N-nitrosamines possessing relatively bulky alkyl chains such as a tobacco-specific nitrosamine, NNK, which has been known to cause lung tumor in rodents. Thus, to examine a hypothesis that individuals possessing the CYP2A6*4C have the reduced risk of lung cancer due to the lack of the capacity of the metabolic activation of certain carcinogens in tobacco smoke, a case-control study was performed.
文摘目的分析西安汉族人群CYP2A6基因拷贝数多态性及其与吸烟行为的关联性。方法选取2021年9月—2023年6月在西安区域医学检验中心体检的西安汉族居民3500例为研究对象。根据受试者是否吸烟,将其分为吸烟组(2233例)和不吸烟组(1267例),根据吸烟组受试者吸烟程度将其进一步分为轻度吸烟亚组(476例)和重度吸烟亚组(1757例)。采用TaqMan®Copy Number Assays试剂盒检测受试者CYP2A6基因拷贝数多态性。结果3500例受试者中,CYP2A6基因拷贝数为0者32例(0.91%),CYP2A6基因拷贝数为1拷贝者632例(18.06%),CYP2A6基因拷贝数为2拷贝者2737例(78.20%),CYP2A6基因拷贝数为≥3拷贝者99例(2.83%)。吸烟组CYP2A6基因拷贝数为0、1拷贝者占比低于不吸烟组,CYP2A6基因拷贝数为2拷贝、≥3拷贝者占比高于不吸烟组(P<0.05)。轻度吸烟亚组与重度吸烟亚组CYP2A6基因拷贝数多态性比较,差异无统计学意义(P>0.05)。结论西安汉族人群CYP2A6基因缺失率较高,达18.97%;西安汉族人群CYP2A6基因拷贝数多态性与吸烟行为可能存在关联,且CYP2A6基因缺失个体不易形成烟草依赖,而CYP2A6基因拷贝数多态性可能与吸烟程度不存在关联。
