同型半胱氨酸及其代谢酶基因多态性与冠心病的关系

目的探讨血浆同型半胱氨酸(Hcy)水平及其代谢酶MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G基因多态性与冠心病的相关性。方法在川东北地区汉族人群中221例冠心病患者(冠心病组)和与之性别、年龄匹配的210例非冠心病患者(对照组)为研究对象。采用Hcy检测试剂盒(速率法)测定两组患者血浆Hcy水平,采用改良多重连接反应检测技术(i MLDR)检测目的基因,进行单核苷酸多态性(SNP)分型,分析两组之间Hcy水平及其Hcy代谢酶基因多态性分布情况。结果 (1)冠心病组血浆Hcy水平明显高于对照组(15.39±6.89μmol/L比12.90±6.44μmol/L,P0.05),Hcy在两组之间比较OR值为1.060(95%CI 1.021~1.100),差异具有统计学意义(P0.05)。(2)MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G在两组之间比较,无论是基因型分布频率还是等位基因分布频率均无统计学差异(P均0.05);基因-基因间交互作用分析发现,这四个基因位点在冠心病的发病过程中不存在交互作用(P0.05);基因-环境间交互作用分析发现,MTHFR C677T与吸烟、甘油三酯之间也不存在交互作用(P均0.05)。(3)血浆Hcy水平在冠心病MTHFR TT基因型组(19.72±11.51μmol/L)最高,且分别高于CC基因型组(13.99±4.77μmol/L,P0.05)及CT基因型组(15.44±6.25μmol/L,P0.05)。结论 Hcy可能增加川东北地区汉族人群冠心病的患病风险,MTHFR C677T TT基因型的冠心病患者血浆Hcy水平较高,未发现MTHFR C677T、MTHFR A1298C、MS A2756G、MTRR A66G基因多态性与冠心病发病相关。     

同型半胱氨酸代谢相关酶基因多态性与先天性心脏病的关系

目的研究同型半胱氨酸相关酶中亚甲基四氢叶酸还原酶(MTHFR)、蛋氨酸合成酶(MS)和蛋氨酸合成酶还原酶(MTRR)基因的多态性与先天性心脏病(CHD)的相关性。方法采用病例对照研究方法,以132例CHD患儿(疾病组)与107名健康儿童(对照组)的血白细胞为样本,应用聚合酶链反应-限制性片段长度多态性技术检测两组的MTHFR基因第677位点、MS基因第2756位点及MTRR第66位点的多态性,比较两组各自的基因型和等位基因的分布频率。结果MTHFR的677位点CC、CT和TT基因型在疾病组中分别为22.73%、51.52%、25.76%,在对照组中分别为42.99%、44.86%、12.15%,两组的分布频率差异有统计学意义。MS基因第2756位点AA、AG和GG基因型在疾病组和对照组中的分布频率差异无统计学意义。MTRR基因第66位点AA、AG和GG基因型在疾病组分别为25.00%、63.64%、11.36%,在对照组中分别为48.60%、42.05%、9.35%,两组的分布频率差异有统计学意义。结论①MTHFR及MTRR的基因多态性与CHD的发病具有一定程度的相关性,MS基因的多态性分布与CHD的发病无关;②MTHFR基因第677位点中的C/C及MTRR第66位点中的A/A均为CHD的保护基因;③两基因变异在CHD的发病中可能有协同作用。     

同型半胱氨酸水平与冠心病的关系

目的观察同型半胱氨酸(Hey)水平与冠心病(CHD)的关系,并探讨蛋氨酸合成酶还原酶(MTRR)A66G基因多态性、叶酸、维生素B12(VitB12)与Hcy水平及CHD的关系。方法 选择190例经冠状动脉造影证实的CHD患者(CHD组)和100例冠状动脉造影正常者为对照组。应用荧光偏振免疫分析法测定Hey水平,离子捕获分析法测定叶酸水平,微粒酶免疫分析法测定VitB12水平。聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法分析MTRRA66G基因多态性。结果 CHD组血Hcy水平显著高于对照组(15.8±8.8)μmol/L与(12.9±6.3)μmol/L,P=0.002。叶酸、VitB12水平与血Hcy水平呈负相关。叶酸、VitB12与CFD无关。MTRR A66G基因多态性GG纯合子、AG杂合子和AA野生型3种基因型组间血Hcy水平差异无显著性意义。(P=0.908)。MTRR A66G各基因型在CHD组和对照组的分布差异无显著性意义(P=0.198)。结论CHD患者血Hcy水平升高,叶酸、VitB12水平与血Hcy水平呈负相关。MTRR A66G基因多态性与血Hcy水平及与CHD均无关。     

MTHFR基因多态性与急性心肌梗死的相关性分析

目的：研究同型半胱氨酸浓度及MTHFR基因多态性与急性心肌梗死（Acute myocardial infarction, AMI）之间的相关性。方法 ：选取我院2013年10月~2016年4月在我院就诊的60例AMI患者作为实验组,其中男性37例,女性23例,平均年龄66.3±10.4岁。选取同期我院行健康体检的人群60例作为对照组,其中男性39例,女性21例,平均年龄68.7±11.1岁。分别测定两组血浆同型半胱氨酸（Homocysteine,Hcy）浓度、叶酸浓度水平以及MTHFR基因的多态性。分析两组之间MTHFR基因 C677T 多态性的分布及 Hcy 水平。 结果：AMI组血浆Hcy浓度水平(18.74±3.71umol/L)明显高于对照组(10.74±5.11umol/L),差异具有明显统计学意义（P＜0.05）;AMI组患者的叶酸浓度水平(4.87±3.16ng/ml)明显低于对照组(9.71±2.97ng/ml)（P＜0.05）;叶酸与Hcy浓度水平之间呈负相关性;AMI组患者的MTHFR基因TT纯合子组的血浆Hcy水平(19.74±3.16umol/L)与CT杂合子(13.68±3.94umol/L)和CC纯合子(12.41±1.54umol/L)相比明显增高（P＜0.05）;与健康对照组相比AMI组TT纯合子的分布频率(AMI组36.67%,对照组16.67%)明显增高（P＜0.05）;并且AMI组的T等位基因频率（AMI组58.33%,对照组38.33%）明显增高（P＜0.05）。结论：Hcy在血浆中的浓度水平与AMI的发病之间有着密切的联系,MTHFR基因的多态性与AMI易感性密切相关,MTHFR基因T等位基因可能是导致AMI的风险基因突变。     

胃癌组织中叶酸水平与代谢酶亚甲基四氢叶酸还原酶基因多态性的关系研究

目的探讨人胃癌组织中叶酸水平与代谢酶亚甲基四氢叶酸还原酶(MTHFR)基因多态性的变化及其关系。方法收集38例晚期胃癌患者的癌区、癌旁和外周正常区域组织标本,以自动化学发光系统测定人胃癌组织叶酸含量,PCR-限制性内切酶片段长度多态性技术检测MTHFR基因677(C→T)和1298(A→C)两个常见多态,并以34例慢性浅表性胃炎(CSG)组织作为对照,分析叶酸、MTHFR基因多态性的变化及其关系。结果CSG对照组中叶酸含量[(5.48±2.15)ng/ml]明显高于胃癌组织[癌区(3.65±1.97)ng/ml,癌旁(4.01±2.11)ng/ml,外周正常组织(4.00±2.20)ng/ml],胃癌组织MTHFR基因的两个多态位点中,677CT基因型叶酸含量最高,而1298(A→C)多态则未见明显差异。677TT基因型与CC基因型相比有减少胃癌发生的趋势,但与其生物学行为关系不密切。677TT基因型高叶酸组与CC基因型低叶酸组相比发生胃癌的相对风险度为0.11(95%CI:0.01~1.02)。癌组织标本检测中未发现1298CC基因型。结论组织叶酸含量降低者发生胃癌风险明显增加。MTHFR基因多态性并不是胃癌的一个孤立危险因素,它和组织叶酸含量共同作用于胃癌发生。     

高血压患者血浆同型半胱氨酸水平及亚甲基四氢叶酸还原酶基因多态性的研究

目的探讨高血压患者血浆同型半胱氨酸(Hcy)水平及亚甲基四氢叶酸还原酶(MTHFR)A1298C基因多态性对血浆Hcy水平的影响。方法选择原发性高血压患者145例,采用荧光偏振免疫法测定血浆Hcy水平,依据Hcy水平将研究对象分为H型高血压组及非H型高血压组。并应用聚合酶链反应-限制性内切酶片段长度多态性技术检测MTHFR基因多态性。结果 H型高血压组及非H型高血压组血浆平均Hcy水平分别为(16.74±6.14)μmol/L,(8.50±1.02)μmol/L,两者差异有统计学意义(P<0.05)。H型高血压组及非H型高血压组MTHFRA1298C多态位点AA、AC及CC基因型频率分布及C等位基因频率差异均无统计学意义(P>0.05)。AA、AC和CC 3种基因型间的平均血浆Hcy水平比较差异无统计学意义(P<0.05)。结论 H型高血压患者血浆Hcy水平较非H型高血压显著升高,MTHFR A1298C多态位点对血浆Hcy水平无明显影响。     

亚甲基四氢叶酸还原酶基因C677T、A1298C和G1793A多态性与血液透析患者血浆Hcy水平的关系

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因C677T、A1298C和G1793A多态性与血液透析患者血浆同型半胱氨酸(Hcy)水平的关系。方法接受血液透析的慢性肾衰竭患者(疾病组)88例的外周血标本,采用直接测序法对MTHFR基因3个标签(C677T、A1298C和G1793A)单核苷酸多态性(SNPs)进行基因分型,选取同期92例健康体检者的外周血作对比(对照组),比较两组以上SNPs位点基因型和等位基因的分布差异,采用酶联免疫吸附法检测血浆Hcy水平并比较疾病组MTHFR基因SNPs位点各基因型的血浆Hcy水平,以比值比(OR)及其95%置信区间(CI)评价以上SNPs发生Hcy升高的风险情况。结果两组C677T和G1793A基因型和等位基因分布差异有统计学意义(P0.05),其中疾病组C677T TT基因型和T等位基因的比例及G1793A AA基因型和A等位基因的比例明显高于对照组(P0.05)。疾病组血浆Hcy水平为(38.25±4.67)μmol/L,显著高于对照组的(19.36±2.59)μmol/L(P0.05)。疾病组C677T TT型的血浆Hcy水平高于CC、CT型,CT型高于CC型,G1793A AA型的血浆Hcy水平高于GG、GA型,GA型高于GG型,差异均有统计学意义(均P0.05)。C677T TT基因型较CC型血浆Hcy水平升高的风险升高至3.429倍(P0.05),而GA、GA+AA型血浆Hcy水平升高的风险未改变(P0.05);以C等位基因为参照,携带T等位基因者Hcy水平升高的风险升高至2.050倍(P0.05)。A1298C、G1793A位点血浆Hcy水平升高的风险均未改变(P0.05)。结论MTHFR C677T和G1793A携带突变基因者的血浆Hcy水平升高,其中C677TT等位基因的血浆Hcy水平升高的风险升高,在预测血液透析患者血浆Hcy水平异常上有一定价值。     

血浆同型半胱氨酸及其代谢酶基因多态性与溃疡性结肠炎的相关性研究

目的 探讨血浆同型半胱氨酸(Hcy)、叶酸和维生素B12水平及Hcy代谢酶基因多态性与溃疡性结肠炎(UC)的关系.方法 收集310例UC患者和936名正常对照者,采用聚合酶链反应-限制性片断长度多态性(PCR-RELP)法检测亚甲基四氢叶酸还原酶(MTHFR)C677T、A1298C、甲硫氨酸合成酶(MTR) A2756G和甲硫氨酸合成还原酶(MTRR) A66G基因多态性;并从中随机选取88例UC患者和100名正常对照者,采用循环酶法检测血浆Hcy水平,微粒子免疫化学发光法检测叶酸和维生素B12浓度.结果 UC患者MTHFR A1298C、MTR A2756G和MTRRA66G突变的等位基因及基因型频率均明显增高(P值均<0.01).UC患者Hcy平均水平为(21.73±6.59)mmol/L,较正常对照组显著增高[(12.47±5.01)mmol/L,P<0.01],而叶酸和维生素B12平均水平分别为(11.25±6.19)nmol/L和(322.81±128.47)pmol/L,明显较正常对照组降低[(15.28±7.72)nmol/L和(422.59±129.36)pmol/L,P值均<0.01].Logistic回归分析提示血浆Hcy、叶酸和维生素B12浓度是UC的独立危险因素(P值均<0.01).结论 Hcy代谢酶基因多态性及血浆Hcy、叶酸和维生素B12水平异常与UC明显相关,为临床采用叶酸、维生素B12补充疗法治疗UC提供了理论依据.     

脂蛋白脂酶基因Ser447Ter变异对血脂的影响

目的　探讨脂蛋白脂酶 (LPL)基因Ser447Ter变异是否影响血脂水平。方法　 2 52例受试者 ,其中 1 32例冠心病患者及 1 2 0例非冠心病者。采用聚合酶链式反应 限制性片段多态性方法检测LPL基因多态性。结果　LPL基因Ser447Ter突变杂合子 (CG型携带者 )和纯合子 (GG型携带者 )血甘油三酯浓度 [(1 1 7± 0 55)mmol L]低于无Ser447Ter突变者 [CC型携带者 ,(1 64± 1 1 1 )mmol L] ,P<0 0 1 ;前者高密度脂蛋白 胆固醇水平 [(1 2 4± 0 2 7)mmol L]高于后者 [(1 1 3± 0 2 7)mmol L] ,P <0 0 5 ;这种效应女性携带者更为明显。但是 ,男女两性Ser447Ter各基因型的比例相近。结论　LPLSer447Ter突变可影响血脂水平 ,且存在男女性别差异 ,各LPL基因型的分布无性别差异     

亚甲基四氢叶酸还原酶677C→T及1298A→C基因多态性与糖尿病心血管病变的相关性

目的探讨亚甲基四氢叶酸还原酶(MTHFR)基因多态性与糖尿病心血管并发症(DC)的关系. 方法应用PCR-RFLP法检测84例健康人(NC)和158例2型糖尿病患者[分为无DC(NDC)和DC组]的MTHFR677C→T及1298A→C基因多态性,比较各组间基因型分布和等位基因频率. 结果 DC组MTHFR677 TT基因型分布及T等位基因频率均高于NC或NDC组,且叶酸水平较低(P<0.001); 各组间MTHFR1298A→C基因型分布及等位基因频率差异无统计学意义(P>0.05);MTHFR基因型、年龄是DC的危险因子. 结论 MTHFR677C→T突变与DC的发生有关.     

Alternative adaptations, speciation, and phylogeny (A Review)

Alternative adaptations—different adaptive phenotypes maintained in the same life stage and the same population but not necessarily simultaneously expressed in the same individual—represent contrasting character sets produced by the same genome, in effect allowing a single species to occupy more than one sympatric niche. Such alternatives are particularly likely to give rise to novel adaptations because of selection for extreme dissimilarity between them and because established traits buffer populations against extinction while independently expressed alternatives evolve in new directions. Particular alternatives can be suddenly fixed in populations with little or no genetic change, leading to a period of rapid evolution (especially, of morphology) exaggerating the characteristics of the newly fixed form. This burst of change would facilitate rapid speciation and could produce “punctuated” patterns of evolution. Evidence from a wide variety of organisms shows that alternative phenotypes are exceedingly common in nature and that they are probably important in speciation and macroevolution. Although many of these ideas and observations have been noted piecemeal by previous authors, bringing them together demonstrates the probable importance of alternative adaptations in the origin of major evolutionary novelties and calls for a revision of current and traditional ideas about the role of behavior and ontogeny in the genesis of organic diversity.     

A maximal function associated to the curve (t, t)

The authors prove that [Formula: see text] is bounded from L^P(R²) to L^P(R²) for 1 < p ≤ ∞.     

The role of the D(2) dopamine receptor (D(2)R) in A(2A) adenosine receptor (A(2A)R)-mediated behavioral and cellular responses as revealed by A(2A) and D(2) receptor knockout mice

The A(2A)R is largely coexpressed with D(2)Rs and enkephalin mRNA in the striatum where it modulates dopaminergic activity. Activation of the A(2A)R antagonizes D(2)R-mediated behavioral and neurochemical effects in the basal ganglia through a mechanism that may involve direct A(2A)R-D(2)R interaction. However, whether the D(2)R is required for the A(2A)R to exert its neural function is an open question. In this study, we examined the role of D(2)Rs in A(2A)R-induced behavioral and cellular responses, by using genetic knockout (KO) models (mice deficient in A(2A)Rs or D(2)Rs or both). Behavioral analysis shows that the A(2A)R agonist 2-4-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine reduced spontaneous as well as amphetamine-induced locomotion in both D(2) KO and wild-type mice. Conversely, the nonselective adenosine antagonist caffeine and the A(2A)R antagonist 8-(3-chlorostyryl)caffeine produced motor stimulation in mice lacking the D(2)R, although the stimulation was significantly attenuated. At the cellular level, A(2A)R inactivation counteracted the increase in enkephalin expression in striatopallidal neurons caused by D(2)R deficiency. Consistent with the D(2) KO phenotype, A(2A)R inactivation partially reversed both acute D(2)R antagonist (haloperidol)-induced catalepsy and chronic haloperidol-induced enkephalin mRNA expression. Together, these results demonstrate that A(2A)Rs elicit behavioral and cellular responses despite either the genetic deficiency or pharmacological blockade of D(2)Rs. Thus, A(2A)R-mediated neural functions are partially independent of D(2)Rs. Moreover, endogenous adenosine acting at striatal A(2A)Rs may be most accurately viewed as a facilitative modulator of striatal neuronal activity rather than simply as an inhibitory modulator of D(2)R neurotransmission.     

Cytochrome P450 (CYP) 1A2, sulfotransferase (SULT) 1A1, and N-acetyltransferase (NAT) 2 polymorphisms and susceptibility to urothelial cancer

Purpose Arylamines are suspected to be the primary causative agent of urothelial cancer in tobacco smoke. In the human liver, arylamines are N-hydroxylated by a cytochrome P450 (CYP)1A2-catalyzed reaction, which produces a substrate for O-esterification that can be catalyzed by N-acetyltransferases (NAT) or sulfotransferases (SULT). Recently, several polymorphisms of CYP1A2, SULT1A1, and NAT2 that affect their activities have been reported.Methods In this study, 306 Japanese patients with urothelial transitional cell carcinoma and 306 healthy controls were compared for frequencies of CYP1A2, SULT1A1, and NAT2 genotypes.Results The frequencies of NAT2 intermediate or slow acetylator genotype were significantly higher in the urothelial cancer patients than in the healthy control subjects [odds ratio (OR)=1.49, 95% confidence interval (95% CI) 1.06–2.09, OR=3.23, 95% CI 1.72–6.08, respectively]. Stratifying by amount of smoking, among subjects who consumed >33.5 pack-years and carried the SULT1A1 *1/*1 or NAT2 slow acetylator genotype, the OR was 1.73 (95% CI 1.01–2.97) whereas it was 7.31 (95% CI 1.90–28.05) in non-smokers who carried the homozygous wild genotype, respectively. The relationships between CYP1A2, SULT1A1, and NAT2 polymorphisms and clinical findings including tumor differentiation, stage, and recurrence rate were analyzed. Only associations between NAT2 genotype and pathological findings were admitted, and the higher OR of NAT2 intermediate and slow acetylator genotype was more likely to present to a low-grade tumor (G1) among heavy-smokers.Conclusions Our results suggest that SULT1A1 *1/*1 and NAT2 slow acetylator genotypes might modulate the effect of carcinogenic arylamines contained in tobacco smoke, and that the modulation of NAT2 intermediate and slow acetylator genotype has a tendency to present a higher risk for highly differentiated tumors among heavy-smokers.     

Chronic Obstructive Pulmonary Disease (COPD) and Vapors,Gases, Dusts,or Fumes (VGDF): A Meta-analysis

To evaluate the association between the risk of chronic obstructive pulmonary disease (COPD) and exposure to vapors, gases, dusts, or fumes (VGDF), we conducted a meta-analysis of epidemiological studies. We searched for studies investigating the relationship between COPD and occupational exposure to VGDF in the adult population. The bibliographic search was conducted in databases (PubMed and Google Scholar). Eleven studies that met predetermined inclusion criteria were included in the meta-analysis. We calculated the pooled odds ratio (OR) with its 95% confidence interval (CI) of COPD for exposure to VGDF using a random-effects model. The presence of publication bias was explored. There was moderate heterogeneity among the included studies (I² = 54.3%). In a random-effects model meta-analysis, the pooled OR for exposure to VGDF was 1.43 for COPD (95% CI: 1.19–1.73) compared with no exposure to VGDF. Publication bias was not observed in this study. Our study suggests that exposure to VGDF is associated with a higher risk of COPD. Further prospective cohort studies are needed to confirm this association.