细胞色素2E1及谷胱甘肽S-转移酶M1基因多态性研究

目的了解湖南汉族、苗族、土家族正常人群细胞色素2E1(CYP2E1)及谷胱甘肽-S转移酶M1(GSTM1)基因多态性分布。方法2004年12月至2005年1月,采用聚合酶链式反应(PCR)聚合酶链式反应-限制性片段长度多态性(PCR-PFLP)方法对120名汉族,110名苗族,108名土家族正常人的GSTM1及CYP2E1的PstⅠ多态性进行了分析。结果CYP2E1(c1c2,c2c2)、GSTM1(-)基因型在湖南汉族、苗族和土家族同时具有CYP2E1(c1c2,c2c2)、GSTM1(-)基因型的频率分别为24·17%、18·19%、18·52%,各个民族间差异无显著性(P>0·05);CYP2E1及GSTM1基因型分布不受年龄性别的影响。结论湖南汉族、苗族和土家族CYP2E1及GSTM1基因多态性分布大体类似,但与国外其他种族显著不同。     

CYP2E1,GSTM1基因多态性与甘肃地区食管癌易感性

目的探讨细胞色素氧化酶P450,GSTM1的基因多态性与甘肃地区食管癌遗传易感性之间的以及基因—基因的交互作用。方法运用病例对照分子流行病学研究方法和聚合酶链反应方法对食管癌病例组和正常对照组基因DNA进行CYP2E1,GSTM1基因分型。结果CYP2E1基因pst1多态性的三种基因型在食管癌组和对照组的频率差异有统计学意义（χ2=12.59,P〈0.05）。携带C1/C1基因型个体发生食管癌的风险是携带其他基因型2.80倍（OR=2.80,95%C I=1.21-6.46）。食管癌组GSTM1（-）基因型频率显著高于对照组（χ2=10.292,P〈0.05）,携带GSTM1（-）的个体患食管癌的危险性显著高于GSTM1（＋）基因型的个体（OR=2.337,95%C I=1.39-3.93）。联合分析CYP2E1基因pst1多态性和GSTM1基因多态性,携带有C1/C1和GSTM1（-）基因型的个体患食管癌的风险高于携带GSTM1（＋）和C1/C2或C2/C2基因型的个体（OR=3.00,95%C I=1.7375-5.182）。结论CYP2E1,GSTM1基因多态性与食管癌易感性有关联,CYP2E1基因C1/C1基因型是食管癌的易感性基因,而GSTM1基因缺失使食管癌危险性增加,CYP2E1,GSTM1存在交互作用。     

ⅠⅡ相代谢酶基因多态性与食管癌遗传易感性的病例对照研究

目的研究细胞色素P450（CYP）1A1和谷胱甘肽转硫酶M1（GSTM1）和T1（CSlTrl）基因多态性与食管癌易感性的关系。方法应用PCR—RFLP技术对87例食管癌患者和162例无上消化道肿瘤的健康者的CYP1A1、GSTMl和GSlTrl的基因多态性进行分析。比较两组基因型频率的差异。结果食管癌组CYPlAlIle—Val多态位点各等位基因和基因频率与对照组比较，差别有统计学意义，其中Val／Val基因型在食管癌组的频率（29．9％）显著高于对照组（13．0％）（X^2=10．54，P〈0．01），OR值为3．10，95％CI为（1.57，6．14），而CYPlAl的Ⅱe／Val、Ⅱe／Ⅱe多态位点和GSTMl与GSTTl的缺失多态性的基因型频率与对照组比较，差别无统计学意义（P〉0．05）。结论CYPlAlVal／Val基因型为食管癌的重要易感因素之一，而GSTMl与GSTTl的基因型可能与食管癌的发生无关。     

细胞色素P450基因多态性与肺癌易感性的相关性分析

目的 探讨代谢活化酶细胞色素P4501A1（CYP1A1）、2D6（CYP2D6）、2E1（CYP2E1）和代谢解毒酶谷胱甘肽硫转移酶（GSTM1）与肺癌易感性的关系。方法采用PCR、PCR—RFLP技术检测原发性肺癌组（279例）及对照组（684例）的CYPlAI、CYP2D6、CYP2E1、GSTM1代谢酶基因型，对不同基因型在两组分布频率的差异进行OR值的统计分析。结果CYPlAl突变等位基因（m）、GSTMl功能缺失型（-）分别可使患肺癌的危险性增加1．64（OR=1．64，95％CI为1．21—2．22，P=0．001）和1．58倍（oR=1．58，95％CI为1，19—2．11，P=0．002）。其中CYPlAl与肺鳞癌、小细胞癌，GSTMl与肺鳞癌及肺腺癌明显相关（均P〈0．05）。同时携带GSTMI（-）和CYPlAl（m）可使患肺癌的危险性明显增加（OR=2．75，95％CI为1．73～4．39，P=O．OOO）。在重度吸烟人群携带GSTMl（-）、CYPlAl（m）、CYP2D6（W）或CYP2ElA基因型均可使患肺癌的危险性显著增加5．71—11．67倍（辟O．000）。结论携带GSTMI（-）及CYPlAl（m）等位基因型者患肺癌的危险性上升，二者有协同作用。在重度吸烟人群，CYP及GSTMl的检测有利于发现肺癌的高危人群。     

谷胱甘肽转硫酶M1基因多态性与溃疡性结肠炎易感性的关系

背景：谷胱甘肽转硫酶（GST）属Ⅱ相代谢酶，能催化亲电子底物与谷胱甘肽结合而排出体外。溃疡性结肠炎（UC）为复杂的多基因遗传性疾病，其发病机制至今不明。目的：探讨GSTM1基因多态性与UC易感性的关系。方法：采用聚合酶链反应（PCR）检测68例UC患者和140名健康对照者的GSTM1基因型，分析两组间GSTM1基因型分布频率的差异。结果：UC组GSTM1（-）基因型的分布频率显著高于健康对照组（63．2％对45．0％，P=0．014）。根据病变范围对UC组行分层分析，发现远端UC组GSTM1（-）基因型的分布频率显著高于广泛UC组（72．7％对45．8％。P=0．028）。结论：GSTM1基因多态性与UC易感性明显相关。     

CYP1A1、GSTM1基因多态性与肺癌遗传易感性的关系

目的 探讨CYP1A1 m1、m2位点和GSTM1基因多态性与肺癌遗传易感性的关系.方法采用病例对照研究方法和寡核苷酸芯片技术对110例山东汉族肺癌患者和125例正常对照者的基因组DNA进行CYP1A1、GSTM1基因多态性分析.结果 CYP1A1 m2位点、GSTM1基因型分布在肺癌组和对照组间存在统计学差异(P<0.05);携带CYP1A1 Val/Val基因型或GSTM1缺失基因型者患肺癌的危险性增高,其中吸烟个体患肺癌的风险进一步增加.结论 CYP1A1 m2位点和GSTM1基因多态性可能与肺癌发生有关,吸烟与CYP1A1、GSTM1基因具有协同作用.     

CYP1A1及GSTM1基因多态性对肺癌发病的影响

目的探讨代谢活化酶细胞色素P4501A1（CYP1A1）及谷胱甘肽硫转移酶M1（GSTM1）基因多态性和环境暴露与肺癌易感性的关系。方法用聚合酶链反应—限制性片段长度多态性技术测定158例肺癌患者和455例对照者的CYP1A1及GSTM1基因多态性。结果与对照组比较，肺癌组吸烟、粉尘接触频率明显升高，而摄入蔬菜水果及消毒水频率明显降低（P均〈0．01）；两组CYP1A1与GSTM1基因各类型分布无统计学差异；CYP1A1突变型基因及GSTM1缺陷型与吸烟有协同致肺癌作用。结论吸烟、接触粉尘均增加肺癌发生率，而摄入蔬菜水果及消毒水降低其危险性；吸烟可增加CYP1A1基因突变型或GSTM1基因缺陷型个体肺癌发生的危险性。     

谷胱甘肽硫转移酶M1和T1基因多态性与燃煤型砷中毒发病的关系

目的探讨谷胱甘肽硫转移酶M1和T1（GSTM1、GSTT1）基因多态性与燃煤污染型砷中毒发病风险的关系。方法采用多重等位基因特异聚合酶链反应技术检测贵州省130名燃煤型砷中毒患者及140名健康个体的GSTM1和GSTT1基因多态性，并分析不同基因型与砷中毒发病的关系。结果砷中毒病例组和对照组GSTT1纯合缺失基因型（GSTT1^（-/-））的频率分别为58．5％和45．0％，组间比较差异有统计学意义（Х^2=6．246，P〈0．05）；携带GSTT1^（-/-）基因型个体发生砷中毒的风险是携带GSTT1非纯合缺失基因型（GSTT1^（＋/＋）or（-/-））个体的2．18倍[比值比（OR）adj=2．18，95％可信区间（CI）：1．183～4．018]。砷中毒病例组和对照组间GSTM1纯合缺失基因型（GSTM1^（-/-））频率的差异无统计学意义（P〉0．05）。基因型联合分析显示：携带GSTM1^（-/-）和GSTT1^（-/-）联合基因型的个体，其砷中毒的发病风险显著增加（ORadj=2．931，95％CI：1．024～8．387）。结论GSTT1^（-/-）基因型可能是燃煤型砷中毒发生的重要危险内因之一。     

SCNN1A基因多态性与土家族、苗族及汉族人群原发性高血压相关性的研究

目的:探讨上皮细胞钠通道α亚基(SCNN1A)基因单核苷酸多态性位点rs2228576与湘西土家族、苗族和汉族人群原发性高血压(EH)的相关性。方法:用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)技术分析土家族(120例)、苗族(117例)和汉族(125例)人群EH患者(EH组)与正常人群[正常对照组(土家族119例、苗族125例、汉族122例)]SCNN1A等位基因频率分布状况。结果:土家族、苗族和汉族均存在3种AA、AG及GG基因型;土家族、苗族和汉族正常对照组基因型频率分别为(0.109,0.538,0.353;0.152,0.472,0.376;0.164,0.541,0.295);各族EH组与正常对照组基因型频率差异均无统计学意义(χ2=5.662,P>0.843);等位基因频率差异均无统计学意义(χ2=3.538,P>0.618)。结论:3个民族均存在SCNN1A基因rs2228576多态性位点,但该多态性位点与3个民族EH无明显相关性。     

载脂蛋白E基因多态性与脑梗死的关系

目的探讨载脂蛋白E（apoE）基因多态性与脑梗死的关系。方法应用聚合酶链式反应-限制性片断长度多态性（PCR—RFLP）技术检测78例脑梗死患者和90名健康对照者apoE基因多态性分布特征。结果发现5种apoE基因型，脑梗死组E3／4基因型频率（23．1％）及ε4频率（14.7%）显著高于对照组（7．8％，5．0％），P〈0．05。而E3／3基因型频率（56．4％）及ε3频率（75.6%）显著低于对照组（78．9％，88．3％），P〈0．05。不同apoE基因型间胆固醇和低密度脂蛋白胆固醇水平差异有统计学意义（P〈0．05）。结论apoE基因多态性与脑梗死有关，并影响血脂水平。     

1-Naphthyl isocyanate and 1-naphthylamine as metabolites of 1-naphthylisothiocyanate

Abstract: The importance of the bioactivation of 1-naphthylisothiocyanate was studied. Forty minutes after 1-naphthylisothiocyanate administration to rats, bile was collected over a 2.5-h period; the liver was then excised and homogenized. 1-naphthylisothiocyanate and its metabolites in bile and liver of rats were identified and quantified using coupled gas chromatography-mass spectrometry. Three main compounds were found in all 1-naphthylisothiocyanate-treated animals. They were identified as 1-naphthyl isocyanate, 1-naphthylamine and the parent compound, 1-naphthylisothiocyanate. When rats were given cycloheximide, which attenuates 1-naphthylisothiocyanate toxicity, 30 min before 1-naphthylisothiocyanate (300 mg/kg), 1-naphthyl isocyanate concentration was significantly lower than in rats receiving only 1-naphthylisothiocyanate. The appearance of 1-naphthylamine was also inhibited by cycloheximide, although not to the same extent as 1-naphthyl isocyanate. On the other hand, phenobarbital, which potentiates 1-naphthylisothiocyanate hepatotoxicity, enhanced 1-naphthyl isocyanate and 1-naphthylamine formation. It is suggested that 1-naphthyl isocyanate, 1-naphthylamine and the highly reactive sulfur released from 1-naphthylisothiocyanate might be involved in the hepatotoxic effect of 1-naphthylisothiocyanate.     

Inhibition of procarcinogen-bioactivating human CYP1A1, CYP1A2 and CYP1B1 enzymes by melatonin

Abstract:  Administration of melatonin to rodents decreases the incidence of tumorigenesis initiated by benzo[ a ]pyrene or 7,12-dimethylbenz[ a ]anthracene, which requires bioactivation by cytochrome P450 enzymes, such as CYP1A1, CYP1A2 and CYP1B1, to produce carcinogenic metabolites. The present study tested the hypothesis that melatonin is a modulator of human CYP1 catalytic activity and gene expression. As a comparison, we also investigated the effect of melatonin on the catalytic activity of CYP2A6, which is also a procarcinogen-bioactivating enzyme. Melatonin (3–300 μ m ) decreased 7-ethoxyresorufin O -dealkylation catalyzed by human hepatic microsomes and recombinant CYP1A1, CYP1A2 and CYP1B1, whereas it did not affect coumarin 7-hydroxylation catalyzed by hepatic microsomes or recombinant CYP2A6. Melatonin inhibited CYP1 enzymes by mixed inhibition, with apparent K _i values (mean ± S.E.M.) of 59 ± 1 (CYP1A1), 12 ± 1 (CYP1A2), 14 ± 2 (CYP1B1) and 46 ± 8 μ m (hepatic microsomes). Additional experiments indicated that melatonin decreased benzo[ a ]pyrene hydroxylation catalyzed by hepatic microsomes and CYP1A2 but not by CYP1A1 or CYP1B1. Treatment of MCF-10A human mammary epithelial cells with melatonin (up to 300 μ m ) did not affect basal or benzo[ a ]pyrene-inducible CYP1A1 or CYP1B1 gene expression. Consistent with this finding, melatonin did not influence reporter activity in aryl hydrocarbon receptor-dependent pGudluc6.1-transfected MCF-10A cells treated with or without benzo[ a ]pyrene, as assessed in an in vitro cell-based luciferase reporter gene assay. Overall, melatonin is an in vitro inhibitor of human CYP1 catalytic activity, and it may be useful to develop potent analogues of melatonin as potential cancer chemopreventive agents that block CYP1-mediated chemical carcinogenesis.     

The target of ezetimibe is Niemann-Pick C1-Like 1 (NPC1L1)

Ezetimibe is a potent inhibitor of cholesterol absorption that has been approved for the treatment of hypercholesterolemia, but its molecular target has been elusive. Using a genetic approach, we recently identified Niemann-Pick C1-Like 1 (NPC1L1) as a critical mediator of cholesterol absorption and an essential component of the ezetimibe-sensitive pathway. To determine whether NPC1L1 is the direct molecular target of ezetimibe, we have developed a binding assay and shown that labeled ezetimibe glucuronide binds specifically to a single site in brush border membranes and to human embryonic kidney 293 cells expressing NPC1L1. Moreover, the binding affinities of ezetimibe and several key analogs to recombinant NPC1L1 are virtually identical to those observed for native enterocyte membranes. KD values of ezetimibe glucuronide for mouse, rat, rhesus monkey, and human NPC1L1 are 12,000, 540, 40, and 220 nM, respectively. Last, ezetimibe no longer binds to membranes from NPC1L1 knockout mice. These results unequivocally establish NPC1L1 as the direct target of ezetimibe and should facilitate efforts to identify the molecular mechanism of cholesterol transport.     

甲型H1N1与季节性H1N1流感病毒血凝素基因比较分析

目的分析泰安市2008～2009年度季节性流感与2009年度甲型H1N1流感病原学检测结果 ,比较季节性H1N1与甲型H1N1血凝素基因变异情况。方法选择国家级流感监测哨点医院以及暴发疫情的疫点,采集流感样病例的鼻咽拭子标本,通过RealtimePCR进行病毒检测,用MDCK细胞进行病毒分离,通过RT-PCR扩增血凝素HA1片段的基因并测序,利用生物信息学进行序列分析。结果 2008～2009年共检测鼻咽拭子标本283份,分离出流感病毒33株,分离阳性率为11.67%,其中季节性H1N1亚型31株。2009年5月1日～12月31日,检测鼻咽拭子标本996份,流感核酸检测阳性417份,阳性率为41.86%,其中甲型H1N1337份,季节性H1N1亚型1份。6株季节性H1N1病毒均在多个氨基酸位点上发生变异,与疫苗株A/Brisbane/59/2007(H1N1)比较,有11个位点发生了突变,其中5个位点位于抗原决定簇上;测序成功的6株甲型H1N1病毒在多个氨基酸位点发生变异,与疫苗株A/California/07/2009(H1N1)比较,有6个位点发生突变,其中1个位点位于抗原决定簇的B区。结论 2008～2009年度季节性H1N1为优势株,甲流暴发后,甲型H1N1成为绝对优势毒株。季节性H1N1分离株有多处氨基酸替换,抗原决定簇B区变异频繁;甲型H1N1病毒分离株的基因有变异,但关键位点第222位仍为D(天冬氨酸),与疫苗株相比抗原决定簇的关键位点变化不大。     

Characterization of MTHFR,GSTM1, GSTT1, GSTP1, and CYP1A1 genotypes in childhood acute leukemia

The role of methylenetetrahydrofolate reductase (MTHFR C677T), glutathione S-transferases (GSTM1 and GSTT1 null, GSTP1 Ile105Val), and cytochromes p450 (CYP1A1*2A) genotypes in the etiology of childhood leukemia was simultaneously investigated. 144 Turkish children with acute lymphoblastic leukemia (ALL) and 33 with acute nonlymphoblastic leukemia (ANLL) were studied and compared with 185 healthy pediatric controls. The frequency of MTHFR genotype was insignificantly higher in ALL (7.7%) and ANLL (6.3%) than in controls (4.4%). Equal distribution of the GSTM1 null genotype was detected between ALL patients and controls (55%), while its incidence was slightly higher in ANLL patients (61.3%). Although GSTT1 null genotype was insignificantly lower in ALL patients (20.9%) than controls (22.7%), it was significantly underrepresented in ANLL patients (6.5%) (P = 0.05, OR 0.24, 95% CI 0.05-1.03). The homozygous frequency of GSTP1 genotype did not differ significantly between groups of ALL (3.7%), ANLL patients (9.1%) and controls (4.9%). Homozygous CYP1A1*2A genotype was underrepresented in ALL patients (1%) as compared to control (4.8%) but the differences did not reach to statistical significance (OR 0.21; 95% CI 0.03-1.72). Homozygosity for this genotype was not detected in ANLL patients. No particular association was noted between different combinations of combined genotypes and risk of development of childhood ALL and ANLL. These results suggested that there are no significant associations between the studied genotypes and the risk of developing either form of acute leukemia except GSTT1 null and homozygosity for CYP1A1 genotypes that may play protective roles in the development of ANLL in Turkish children.     

Cytochrome 1A1 and 1B1 gene diversity in the Zanzibar islands

Amodiaquine (AQ) is a 4‐aminoquinoline widely used in the treatment of malaria as part of the artemisinin combination therapy (ACT). AQ is metabolised towards its main metabolite desethylamodiaquine mainly by cytochrome P450 2C8 (CYP2C8). CYP1A1 and CYP1B1 play a minor role in the metabolism but they seem to be significantly involved in the formation of the short‐lived quinine‐imine. To complete the genetic variation picture of the main genes involved in AQ metabolism in the Zanzibar population, previously characterised for CYP2C8, we analysed in this study CYP1A1 and CYP1B1 main genetic polymorphisms. The results obtained show a low frequency of the CYP1A1*2B/C allele (2.4%) and a high frequency of CYP1B1*6 (approximately 42%) followed by CYP1B1*2 (approximately 27%) in Zanzibar islands. Genotype data for CYP1A1 and CYP1B1 show a low incidence of fast metabolisers, revealing a relatively safe genetic background in Zanzibar’s population regarding the appearance of adverse effects.