Relationship between mutations of mitochondrial DNA ND1 gene and type 2 diabetes

Background Recent studies have indicated that many mutations in mitochondrial (mt)DNA NDI gene region are related to diabetes mellitus. In this study we explored the relationship between various mtDNA ND1 gene mutations and type 2 diabetes mellitus (DM) among Chinese. Methods Using PCR restriction fragment length polymorphism (PCR-RFLP) analysis and gene sequencing, 4 spots of mtDNA (nt3243, nt3316, nt3394, nt3426) were screened in 478 diabetics and 430 non-diabetic subjects.Results In diabetic group, there were 13 carriers (2.72%)of 3316 G→A mutation,12 (2.51%) of 3394 T→C mutation and 2 (0.42%) of 3426A→G mutation. In controls, only 3394 T→C mutation was observed in 2 subjects (0.47%). There was significant difference in the frequency of 3316 and 3394 mutation between two groups (P<0.05, respectively). More subjects with mitochondrial DNA ND1 gene mutations had DM family history and greater tendency of maternal inheritance when compared to those patients without mutation in diabetic group（P<0.01）. A 3426 mutation diabetic pedigree was studied, and we found 12 maternal members in the family had the same mutation. Conclusion mtDNA ND1 gene mutations at nt3316 (G→A), nt3394 (T→C) and 3426 (A→G) might contribute to the pathogenesis of DM with other genetic factors and environment factors.     

Novel mitochondrial 16S rRNA mutation, 3200T→C, associated with adult-onset type 2 diabetes

Objective To investigate the role of a potential diabetes-related mitochondrial region, which includes two previously reported mutations, 3243A→G and 3316G→A, in Chinese patients with adult-onset type 2 diabetes. Methods A total of 277 patients and 241 normal subjects were recruited for the study.Mitochondrial nt 3116-3353, which spans the 16S rRNA, tRNA(leu(UUR)) and the NADH dehydrogenase 1 gene, were detected using polymerase chain reaction (PCR),direct DNA sequencing, PCR-restriction fragment length polymorphism and allele-specific PCR.Variants were analyzed by two-tailed Fisher exact test. The function of the variants in 16S rRNA were predicted for minimal free energy secondary structures by RNA folding software mfold version 3. Results Four homoplasmic nucleotide substitutions were observed, 3200T→C, 3206C→T, 3290T→C and 3316G→A.Only the 3200T→C mutation is present in the diabetic population and absent in the control population.No statistically significant associations were found between the other three variants and type 2 diabetes.The 3200T→C and 3206C→T nucleotide substitutions located in 16S rRNA are novel variants.The 3200T→C caused a great alteration in the minimal free energy secondary structure model while the 3206C→T altered normal 16S rRNA structure little. Conclusions The results suggest that the 3200T→C mutation is linked to the development of type 2 diabetes, but that the other observed mutations are neutral.In contrast to the Japanese studies, the 3316G→A does not appear to be related to type 2 diabetes.     

Point Mutation in the Parkin Gene on Patients with Parkinson''''s Disease

Summary;To investigate the distribution of possible novel mutations from parkin gene in variant sub-set of patients with Parkinson’s disease(PD)in China and explore whether parkin gene plays an im-portant role in the pathogenesis of PD,70 patients were divided into early-onset group and late-onsetgroup; 70 healthy subjects were included as controls.Genomic DNA from 70 normal controls andfrom those of PD patients were extracted from peripheral blood leukocytes by using standard proce-dures.Mutations of parkin gene(exon 1—12)in all the subjects were screened by PCR-single strandconformation polymorphism(SSCP),and further sequencing was performed in tue samples with ab-normal SSCP results,in order to confirm the mutation and its location.A new missense mutationGly284Arg in a patient and 3 abnormal bands in SSCP electrophoresis from samples of another 3 pa-tients were found.All the DNA variants were sourced from the samples of the patients with early-on-set PD.It was concluded that Parkin point mutation a     

Association of E-cadherin and β-catenin with metastasis in nasopharyngeal carcinoma

Background This study was designed to detect methylation of E-cadherin gene promoter and gene mutation of β-catenin in exon 3 and their expression of protein and mRNA in primary tumor and lymph node metastatic tumor of nasopharyngeal carcinoma (NPC), and investigate the mechanism of invasion and metastasis of neoplastic cells in NPC. Methods Fourty-two fresh biopsy samples were taken from untreated NPC patients at the Affiliated Hospital of Sun Yat-sen Medical College, Sun Yat-sen University, Guangzhou, China during the period of 1999 -2002. Among them 21 were taken from primary tumors and the other 21 from lymph node metastatic tumors. The gene promoter methylation of E-cadherin was detected by methylation-specific PCR (MSP). The mutation in exon 3 of β-catenin was detected by direct sequencing analysis. RT-PCR, Western blot and immunohistochemical staining were used to detect the mRNA and protein expression patterns in both primary and metastatic tumors of NPC. Results Down-regulated expression of E-cadherin in metastatic tumor was compared with that in primary tumor. Reduced expression of E-cadherin was found to be correlated with lymph node metastatic tumor of NPC ( P = 0. 004) ; but there was no obvious correlation between primary and metastatic tumors in the expression of β-catenin (P = 0. 698). The mRNA expression level of Ecadherin in metastatic tumors decreased significantly compared with that in primary tumors. However, little change was observed in the mRNA level of β-catenin in different tumor tissues. Only 4 samples (19. 1%) displayed gene promoter methylation of E-cadherin in primary tumor and 10 samples (47. 6%) showed methylated form of E-cadherin. The gene promoter methylation of E-cadherin was more common in metastatic tumor than in primary tumor of NPC ( P =0. 024). Only 2 (4. 76% ) of the 42 samples showed mutations in exon 3 of β-catenin at 41 (T41A, ACC→GCC) and codon 47(S47T, AGT→ACT). The cytoplasmic and nuclear expression of β-catenin in tumor was not found in any samples of NPC. Conclusions The results suggest that the downregulation of E-cadherin results from the gene promoter aberrant methylation of E-cadherin and that the methylation of E-cadherin plays an important role in invasion and metastasis of tumor cells in NPC. However, β-catenin mutation is an infrequent event in NPC, and β-catenin is not a critical factor influencing the invasion and metastasis of tumor cells in NPC.     

Epidemiology and prevention of hepatitis B virus in China

Hepatitis B virus （HBV） infection is prevalent in China. Approximately 600 million people have ever been infected by HBV. About 130 million are HBV chronic carders and 30 million HB patients. Among them, 50% of HBV carriers are caused by carrier mothers to born infants. Around 300 000 people died of liver disease including liver cirrhosis and primary hepatocellular carcinoma each year and 50% of them died of primary hepatocellular carcinoma. HBV infection is not only the health problem but also becoming a social problem. HBV chronic carriers and patients have endured the great pressure from disease burden and social discrimination. According to the report of the national screening program of HBV released by the ministry of health in 2008, China has taken many effective measures to control the HBV infection, including vaccine immunization program, strengthening the management of blood sources and blood productions, prevention of nosocomial HBV infection, strengthening health education on HBV infection and safe injection techniques. The implementation of HB vaccine immunization program, which China officially introduced into the national immunization program since 1992, has dramatically reduced the incidence of HBV infection among infants and children. Integrated with other interventions, the rate of HBV infection decreased gradually. According to the survey of the national screening program of HBV in 2006, compared with the incidence of HBV in 1992, the incidence rate of HBsAg positive has decreased 26.36%, the number of children who have ever been infected by HBV decreased 80 million since 1992. However some problems are still existing. The solutions of low rate of vaccination in rural areas and migration population, lacking of practical measures on management of hepatitis B patients, the occurrence of health care acquired HBV infection, and low rate of vaccination among high risk groups have also been recommended.     

Detection of HBV and HCV Coinfection by TEM with Au Nanoparticle Gene Probes

Gold(Au) nanoparticle HBV DNA or HCV cDNA gene probes were prepared and were used to detect HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection directly by transmission electron microscopy(TEM).PCR identifying HBV and HCV in serum of patients with HBV and HCV coinfection was established.Alkanethiol-modified oligonucleotide was bound with self-made Au nanoparticles to form nanoparticle HBV DNA or HCV cDNA gene probes through covalent binding of Au-S.HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection was added to the detection system composed of nanoparticle HBV DNA and(or) HCV cDNA gene probes.The results showed that HBV DNA and HCV RNA could be specifically amplified by PCR.The zones of DNA amplification appeared in 431 bp and 323 bp respectively.When HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection were added to the detection system,TEM displayed the nanoparticles self-assembled into large network aggregates.It was concluded that the detection of HBV and HCV coinfection by TEM was convenient and efficient with high specificity and sensitivity.     

Relationship between heterogeneity of HBV preS/S gene and intrauterine transmission

Objective: To study the relationship of the mutation of HBV preS/S gene in HBsAg carrying pregnant women and intrauterine transmission. Methods: Polymerase chain reaction (PCR) was used to amplify HBV preS/S gene from sera of 8 HBsAg carrying pregnant women, 4 women's neonates infected with HBV, and the other's neonates non-infected with. The PCR products were cloned and 5 clones were chosen from every woman for DNA sequencing. Results: Heterogeneity of HBV preS/S gene in HBsAg carrying pregnant women having intrauterine transmission was much higher than that from having not intrauterine transmission, and the divergence rate of nucleotide sequences also higher strikingly. Conclusion: High heterogeneity of HBV preS/S gene of HBsAg positive pregnant women may be relative to high rate of intrauterine transmis-     

Relation between hepatitis B virus genotypes and gene mutation of basic core promoter in Li nationality

Objective:To investigate the relation between hepatitis B virus(HBV) genotypes and the double mutation of A-to-T nucleotide(nt) 1762 and G-to-A nt 1764 in basic core promoter(BCP T1762/A1764) in patients of the Li nationality. Methods:Subjects were 125 HBV DNA positive patients that belong to the Li nationality on Hainan Island. HBV DNA genotype was determined by real time fluorimetry polymerase chain reaction. BCP T1762/A1764 mutation was performed using the direct sequencing method. Results:The prevalence rates of genotype B, genotype C, genotype D, genotype C and D mixed infection(genotype C＋D) and genotype B and D mixed infection (genotype B＋C) were 31.20%, 53.60%, 12.00%, 2.40% and 0.80% respectively. Mutation frequencies in patients infected with HBV genotype C(58.21%) were significantly higher than in those infected with other genotypes (P ＜0.01). The serum viral load of the patients with genotype C(5.74±1.21) was also higher than that of those with genotype B(P ＜0.01). Conclusion:The major genotypes in the Li nationality were genotype C and genotype B. The infection of genotype D and mixed infection also occurred in the Li nationality. Genotype C HBV has a higher replication rate, and the different degrees of pathogenecity among HBV genotypes may be related to BCP T1762/A1764 mutation frequency.     

Association of RFC-1 80A→G and MTHFR 677C→T polymorphisms with neural tube defects in Ukrainian population

【Objective】To evaluate the roles of 80A→G polymorphism of RFC-1 gene encoding the reduced folate carrier protein and 677C→T polymorphism of 5,10-methylenetetrahydrofolate reductase gene(MTHFR)in neural tube defects(NTD)risk in Ukrainian population.【Methods】The folate status,homocysteine levels and genotypes were assessed in 42 mothers of fetuses with spina bifida,anencephaly and encephalocele with the age of 19-40 years.Serum folate and plasma homocysteine levels were estimated using chemiluminescence technology.DNA was isolated from peripheral leukocytes obtained from blood using standard procedures.The presence of the RFC-1 80A→G polymorphism was investigated using polymerase chain reaction(PCR).Real time PCR was used to detect the presence of the 677C→T mutation in the MTHFR gene.【Results】Genotype frequencies for RFC-1 80A→G in NTD group were:homozygous wild type in 9(21.4%),heterozygous type in16(38.1%)women;17(40.5%)women surveyed were found homozygous for the mutant allele genotype of RFC-1(GG).Homozygous for the indicated mutation was found in 57.1%of women with fetal anencephaly in the past history and 29.6%of women with spina bifida fetuses.Allelic frequency in this group of women for allele A was 40.5%(34),for allele G was 59.5%(50).Among women with 80A/A genotype of RFC-1 gene reduced levels of serum folic acid were noticed only in 6(35.5%),but hyperhomocysteinemia was found in 10(58.8%)women.【Conclusion】80G→A polymorphism of RFC-1 gene is a potential genetic factor in the formation of fetus NTD in women of South Ukraine.     

乙型肝炎病毒X基因变异和慢性乙型肝炎患者临床与组织病理学指标的相关性

 目的 探讨慢性乙型肝炎患者肝组织内乙型肝炎病毒（HBV）X基因部分区段的变异与HBV相关各临床与组织病理学指标的关系。方法 以83例慢性乙型肝炎肝穿刺活检标本作为研究对象，20例HBV相关性肝细胞癌作为对照；HBV X基因变异的研究采用PCR扩增和直接双向测序。免疫组化二步法显示肝组织内四种病毒蛋白的表达；荧光实时定量PCR检测肝组织内HBV DNA含量。结果 HBV X基因nt1583～1793区段错义突变主要出现在对应的X蛋白aa87（nt1632、1633）、88（nt1635、1636）、116（nt1719）、118（nt1726、1727）、119（nt1730）、127（nt1752）、130（nt1762）和131（nt1764）位氨基酸。nt1725～1730（aa118/119）突变与肝组织内HBcAg显著低表达（P=0.006），和HBV DNA低拷贝数（P=0.004）明显相关，尤以ACTGAC（TD）型突变最为明显；相反，nt1762/1764（aa130/131）位点突变则伴肝组织内HBcAg显著高表达（P=0.005）和高水平的HBV DNA含量（P=0.006）。同时，肝癌组中nt1725～1730 野生型所占比率明显高于慢性肝炎（P<0.05），而nt1762/1764 突变型所占比率肝癌组与肝炎组相比显著增高（P<0.01）。结论 肝组织内，在nt1725～1730突变能显著降低HBcAg 的表达和HBV DNA水平，nt1762/1764突变则相反。肝组织内HBV的高负载可能与肝细胞癌的发生有关     

深圳市乙肝疫苗免疫失败者S基因分析

目的了解乙肝疫苗免疫失败者的HBVS基因的变异情况。方法采用流行病学、ELISA与分子生物学方法,筛选乙肝疫苗免疫失败者。采用聚合酶链反应（PCR）、基因克隆和测序的方法,对乙肝疫苗免疫失败者的HBVS基因进行分析,并与HBV参考序列s基因进行比较,分析其变异情况。结果从2564份受检者中．筛选出2例（0．78％e）HBsAg（-）／HBeAg（＋）／HBcAb（＋）乙肝疫苗免疫失败者（HBsl、HBs2）,经HBVDNA荧光定量PCR检测和HBVS基因PCR扩增,结果均为阳性,为B基因型。其S基因序列与参考序列（JX429908．1）相比,同源性为98．57％,且乙肝疫苗免疫失败者s基因在第363位和第467位分别由野生型的C变为A、G变为A,HBsAg121位和156位氨基酸C和w缺失。结论乙肝疫苗免疫失败者HBVS基因上第363位和第467位碱基存在错义突变（C→A和G→A）,改变了HBsAg的结构和抗原性。     

HBV YMDD变异与HBV-DNA水平的关系

目的 观察拉米夫定治疗慢性乙型肝炎病毒YMDD变异的产生与血清HBV-DVA水平的关系.方法 拉米夫定治疗慢性乙型肝炎患者106例,平均疗程32月(12～48月),治疗前及治疗中每4～6月采血,用荧光实时PCR定量检测HBV-DNA,采用错配聚合酶链反应-限制性片段长度多态性分析的方法检测HBVYMDD变异.分析出现YMDD变异组与非变异组治疗前HBV DNA水平差异.结果 YMDD变异组治疗前血清HBV DNA定量水平显著高于未产生YMDD变异(P＜0.01).结论 慢性乙型肝炎患者治疗前血清病毒载量水平越高,应用拉米夫定治疗越容易产生YMDD变异,且产生时间越早.血清病毒载量可作为应用拉米夫定治疗YMDD变异产生的早期预测指标.     

肝移植术后长期联合应用拉米夫定和小剂量乙肝免疫球蛋白预防乙型肝炎复发的疗效

目的评估肝移植术后长期联合应用拉米夫定(LAM)和小剂量乙肝免疫球蛋白(HBIG)预防乙型肝炎复发的疗效,探讨肝移植术后乙型肝炎病毒(HBV)再感染和乙型肝炎复发的长期联合预防方案。方法通过前瞻性研究中山大学附属第三医院肝脏移植中心1993年10月至2005年8月符合研究标准的190例肝移植,术后应用拉米夫定联合小剂量乙肝免疫球蛋白预防,出现LAM耐药时加用阿德福维(ADV)。依据乙肝病毒标志物、HBVDNA定量、YMDD变异、生化指标和组织病理学检查诊断HBV再感染和乙型肝炎复发。结果190例中出现再感染15例(7.9%),其中肝炎复发7例,加用ADV治疗好转5例,再移植2例;其余HBV再感染8例均加用ADV治疗,血清HBVDNA水平下降5例,转为阴性3例;HBsAg阴转1例。随访时间12～34个月,平均再感染时间8.3月。结论长期联合应用拉米夫定和小剂量乙肝免疫球蛋白可有效预防乙型肝炎复发,加用阿德福维可有效治疗拉米夫定耐药。     

快速检测乙型肝炎病毒前核心区基因变异株方法的建立与初步应用

用聚合酶链反应（ＰＯＲ）选择性地扩增血清标本中乙型肝炎病毒（ＨＢＶ）基因前Ｃ区（Ｐｒｅ－Ｃ）后，以三种寡核苷酸探针Ｍ０（野毒株基因序列）、Ｍ１（ｎｔ．１８９８位点突变株基因序列）、Ｍ２（ｎｔ．１９９８位及ｎｔ．１９０１位上双点突变株基因序列）在极其严谨的条件下分别杂交，检测ＥＢＶＰｒｅ－Ｃ的最常见变异，结果本法具有根高的特异性。应用上述方法检测了３１份乙肝病人的血清标本，结果７份ＨＢｅＡｇ阳性标本中，有４份ＰＣＲ阳性，均与Ｍ０探针杂交，未出现变异；２４份抗－ＨＢｅ阳性标本中，有１０份ＰＣＲ阳性，其中８份表现为Ｍ０伴Ｍ１和（或）Ｍ２阳性，一份为野毒株，另一份与三种探针均不杂交。     

外源辅助T淋巴细胞表位影响HBV S基因DNA免疫的体液免疫应答

目的　探讨外源辅助T淋巴细胞 (HTL)表位对HBVS基因体液免疫应答的影响。方法选用 2种通用HTL表位 ,破伤风类毒素的氨基酸残基 (aa) 830 843片段 (TTE)和人工HTL表位(PADRE) ,以及 3种特异性HTL表位 ,结核杆菌热休克蛋白 6 5的aa1 2 0片段 (TBE)、风疹蛋白E2 4的aa5 4 6 5片段 (ME)和沙眼衣原体热休克蛋白 6 0的aa35 48片段 (CE) ,以单个表位或复合表位形式插入HBVS基因的翻译起始密码下游而构建成真核表达载体。 10 0 μg重组载体DNA免疫BALB/c小鼠 ,3周加强 1次 ,共 3次 ,第三次加强接种后 1月取血采用Abbott试剂盒检测抗 HBs。结果　HBVS基因真核表达载体pHB和 6种外源HTL表位HBVS基因真核表达载体pHB TBE、pHB PADRE、pHB TTE、pHB MTE2、pHB MTE3和pHB MTE5构建成功 ,DNA免疫的抗 HBs水平 (IU/L)分别为 10± 5 ,5± 5 ,49±7,2 9± 6 ,16± 8,2 3± 7和 2 8± 8。单个表位中 ,TTE和PADRE具有良好的免疫促进作用 ,而TBE无促进作用。复合表位均有不同程度的免疫增强作用。结论　部分外源HTL表位对HBVS基因的体液免疫应答有促进作用 ,复合表位中的单个表位间的促进作用无协同或迭加效果。表位PADRE可能用于新型高效乙肝疫苗的研制 ,而复合表位MTE5可能用于能克服人类白细胞抗原多态性的乙肝补种疫     

乙肝病毒基因分型检测芯片的构建及初步应用

目的:构建乙肝病毒(HBV)常见基因型的分型芯片,并应用分型芯片调查HBV基因型分布。方法:应用生物信息学软件针对乙肝病毒4种常见基因型的特征区域和保守区域分别设计分型探针和通用探针,在优化条件下通过重复杂交及分型测序检验芯片的重复性与可靠性后应用于临床,对150例不同类型的乙肝患者进行HBV基因分型。结果:分型探针和通用探针检测重现率分别为94.7%及100%,反馈的测序结果与芯片分型结果完全一致;经芯片分型发现辽宁省HBV基因型分别为C型占68.7%,B型占22.7%,B、C混合型占8.7%,未发现A、D型。结论:基因芯片技术为乙肝病毒基因分型提供了快速准确的检测方法,辽宁地区HBV基因型分布以B、C两型为主,C型占主要优势。     

地高辛标记寡核苷酸探针对慢性乙肝患者前C基因突变的检测

目的　研究慢性乙肝患者乙肝病毒（ＨＢＶ）前Ｃ区突变情况。方法　用多聚酶链反应（ＰＣＲ）结合地高辛标记的寡核苷酸探针Ｍ０（野毒株）、Ｍ１（１８９８位变异株）、Ｍ２（１８９８／１９０１位变异株）对１６５例慢性乙肝患者前Ｃ区突变情况进行检测。结果　其中１２例ＨＢｓＡｇ（＋）,ＨＢｅＡｇ（＋）,抗ＨＢｅ（－）,抗ＨＢｃ（＋）患者,ＨＢＶＤＮＡ阳性率为１００％,突变株检出率为８．３％。１５３例ＨＢｓＡｇ（＋）,ＨＢｅＡｇ（－）,抗ＨＢｅ（＋）,抗ＨＢｃ（＋）患者,ＨＢＶＤＮＡ总阳性率为１６．３％,突变株总检出率为８４％。结论　前Ｃ基因突变株主要存在于抗ＨＢｅ阳性的慢性乙肝患者体内,ＰＣＲ结合地高辛标记的寡核苷酸探针杂交技术,操作简便快捷,利于临床推广应用。