2型糖尿病NEUROD1基因的研究

47例 2型糖尿病 (均 40岁以后发病 )家系先证者PCR SSCP检测出两种NEUROD1基因变异 ;Ala45Thr和Ile15 6Ile。 12 2例 40岁以后发病的 2型糖尿病患者和 13 2例正常对照Ala45Thr基因型和基因频率分布差异无显著性 ,提示NEUROD1基因Ala45Thr突变不是中国人 2型糖尿病的重要遗传因素。     

乙肝病毒基因型的分子生物学特性及其临床意义

乙肝病毒(HBV)基因型是在漫长的岁月中点突变累积形成的,反映了HBV自然感染史发生变异的特点,是病毒变异进化的结果。如果HBV基因序列的某些核酸的改变导致其编码产物抗原位点的改变,就逐渐构成了不同的血清型。目前已根据HBsAg的抗原决定簇的差异将HBV分为4种亚型(adr,adw,ayr,ayw),这些亚型还可进一步细分为9     

MODY3基因在早发家族性2型糖尿病发病中的作用

目的评估MODY3（HNF-1a）基因在中国家族性早发2型糖尿病（T2DM）发病中的作用。方法收集100个早发T2DM家系,PCR扩增先证者MODY3基因的外显子和外显子/内含子拼接区,产物直接测序。对发现的SNPs进行病例对照研究。结果发现5个非编码区DNA变异IVS1-16G〉A、IVS2-23C〉T、IVS5＋9C〉G、IVS7＋7A〉G、IVS9-24C〉T,4个编码区的同义突变Leu17Leu、Gly288Gly、Thr515Thr、Leu459Leu,3个编码区的错义突变Pro379Ala、Ile27Leu、Ser487Asp,其中Pro379Ala突变在一个家系中与糖尿病共分离;Ile27Leu和Ser487Asp与糖尿病不相关。结论MODY3在中国早发家族性T2DM中患病率不超过1%,在中国家族性T2DM发病中不起主要作用。     

尾加压素Ⅱ的基因多态性与2型糖尿病的相关性研究

目的探讨尾加压素Ⅱ(U-Ⅱ)基因Ser89Asn多态性和昆明地区汉族人群2型糖尿病(T2DM)的关系。方法利用聚合酶链式反应限制性片段长度多态性(PCR-RFLP)技术分析T2DM组163例和正常对照组80例U-Ⅱ基因第4外显子89位点由Ser置换成Asn的变异,即Ser89Asn。结果昆明地区汉族人群U-Ⅱ基因正常对照组Ser/Ser56例(70%),Ser/Asn19例(23·8%),Asn/Asn5例(6·2%),T2DM组Ser/Ser83例(50·0%),Ser/Asn67例(40·4%),Asn/Asn16例(9·6%),两组差异有统计学意义(χ2=8·809,P=0·012)。结论U-Ⅱ基因的Ser89Asn多态性和昆明地区汉族人群T2DM的发生有关。     

乙型肝炎病毒S基因变异、基因型与宫内感染免疫失败的关系

目的 探讨HBV S基因变异、基因型与宫内感染免疫失败的关系.方法选择东南大学附属南京第二医院出生的35例宫内感染免疫失败的幼儿及其母亲,实时荧光定量PCR法检测血清HBV DNA含量;并扩增其HBV S基因序列,测序并通过DNASTAR软件与基因库标准序列比对.结果幼儿及其母亲HBV DNA定量检测结果均＞1×106拷贝/mL;幼儿及母亲HBV S基因核苷酸变异率分别为11.4%和17.1%;母婴序列同源性＞99.3%;35对母婴中,23对HBV基因型为C型,血清型为adr亚型,12对为B型,血清型为adw亚型,母婴基因型相同.结论 HBV S基因是否变异可能不是高病毒血症患者宫内感染免疫失败的主要因素;基因分型并不能预测和评价新生儿是否发生宫内感染和免疫失败.     

未经治疗的慢性乙型肝炎患者乙型肝炎病毒耐药变异、基因型和血清型研究

目的 研究未经核苷(酸)类似物(NA)治疗的慢性乙型肝炎患者HBV耐药变异、基因型、基因亚型和血清型特点.方法 从北京大学附属医院收集97例未经NA治疗的慢性乙型肝炎患者血清,用半巢式聚合酶链反应-直接测序法获得HBV全长逆转录酶区序列,用生物信息学技术筛查该区内11个经典耐药变异位点并鉴定基因型、基因亚型和血清型.用统计分析软件SPSS11.0进行t检验和χ~2检验. 结果 HBV在11个经典耐药变异位点上均为野生型氨基酸;B基因型和C基因型分别占36.1%(35/97)和63.9%(62/97),前者均属B2亚型,后者C2亚型占91.9%(57/62),C1亚型占6.5%(4/62),1例未能分出亚型.已知出生地的患者中,71.9%(23/32) B基因型感染者出生于我国南方地区,81.6%(40/49) C基因型感染者出生于北方地区,基因型地域分布特点明显,χ~2=23.19,P<0.01.血清型为adr者占60.8%(59/97),与C基因型相关;为adw者占38.1%(37/97),与B基因型相关,χ~2=87.83,P<0.01.结论 未经NA治疗的慢性乙型肝炎患者体内野毒株为优势株,其基因型、基因亚型和血清型与患者出生地有关.     

慢性乙型肝炎患者HBsAg亚型变化及其临床意义

慢性乙型肝炎患者的 HBsAg 除已知亚型以外,近年发现了 adwr 及 adyr 等新亚型。本文调查93例慢性活动性肝炎,均经组织学证实为本病,并经3年以上观察,应用单克隆抗体的酶免疫法(EIA)定时测定 HBsAg 亚型。结果①慢性乙型肝炎93例中,初诊时 HBsAg亚型为 adr 者64例,adw 者10例,ayr 者1例,adwr者18例.②初诊时 HBsAg 亚型为 adr 的64例中,在     

乙型肝炎病毒亚型基因分类方法及其应用

HBV亚型分类学基础HBV基因组中的S区负责编码不同亚型的表面抗原决定簇;其中的a为共同决定簇,w/r和d/y为相互排斥的亚型决定簇。因此可根据HBsAg,用血清学和免疫学方法将HBV分成adr、adw、ayr和ayw4个主要亚型。虽然也发现了一些特殊的亚型决定簇,如x、n、t、q、Re、j和k等,但并不常见。1975年巴黎国际会议上将HBsAg确定为10个亚型(表1)。由于各亚型之间的HBV-DNA核苷酸序列存在差异,导致其相应的氨基酸序列不同和酶切位点的变化。因此可在基因水平上对HBV进行分类。     

PPAR γ2基因Pro12Ala多态性与高血压病及血脂关系的研究

目的旨在探讨过氧化物酶体增殖物激活受体γ2(PPAR γ2)基因Pro12Ala多态性与高血压病及血脂的关系.方法随机选取湖北地区汉族人237例,其中,正常对照组112例,高血压病组125例.应用聚合酶链反应-限制性片段长度多态性技术,进行基因型检测,并用直接测序法加以证实.结果PPAR γ2基因Pro12Ala多态性的基因型及等位基因频率分布,在高血压病组和对照组间无显著性差异(P＞0.05),提示PPARγ2基因Pro12Ala多态性与高血压病的发病无关.但是在高血压病组中,PA/AA基因型者的血清低密度脂蛋白胆固醇(LDL-C)水平(3.53±0.59)mmol/L,较PP型者(2.47±0.45)mmol/L显著升高(P＜0.05).该变异与体重指数及血压、血糖水平无关(均为P＞0.05).结论PPAR γ2基因Pro12Ala多态性可能不是高血压病发病的遗传学标志.但该变异参与脂质异常的调节,高血压病患者中,PA/AA型者的血清LDL-C水平,较PP型者显著升高.     

结核分枝杆菌对左氧氟沙星与莫西沙星的交叉耐药性及gyrA和gyrB基因突变分析

目的研究结核分枝杆菌(Mycobacterium tuberculosis,MTB)对左氧氟沙星(levofloxacin,LVF)与莫西沙星(moxifloxacin,MXF)的交叉耐药性,分析gyrA和gyrB基因突变位点分布及突变位点与耐药水平的关系。方法采用改良罗氏培养基检测MTB标准菌株H37Rv、66株LVF耐药和55株LVF敏感的MTB临床分离菌株LVF和MXF的最低抑菌浓度(minimal inhibition concentra-tion,MIC)。通过PCR直接测序法测定gyrA和gyrB耐药基因片段。结果 MXF的MIC比LVF低2~4倍,MXF抗MTB菌株的活性是LVF的2~4倍。MTB标准菌株H37Rv未见gyrA和gyrB基因突变。66株LVF耐药和55株LVF敏感菌株均存在gyrA AGC95ACC(Ser→Thr)突变;55株LVF敏感菌株gyrA和gyrB基因未见其他突变。66株LVF耐药菌株中,40株(60.6%)gyrAGAC94(AAC或GGC或GCC或CAC或TAC)(Asp→Asn或Gly或Ala或His或Tyr)突变;19株(28.8%)gyrA GCG90GTG(Ala→Val)和1株(1.5%)gyrA GCG90AAG(Ala→Lys)(未见报导)双碱基突变;3株(4.6%)gyrA TCG91CCG(Ser→Pro)突变;1株(1.5%)gyrB GAC500AAC(Asp→Asn)突变;2株(3.0%)呈gyrA GAC94(AAC或GCC)(Asp→Asn或Ala)与gyrB GGG551AGG(Gly→Arg)(未见报导)双位点突变。gyrA GAC94(AAC或GGC)(Asp→Asn或Gly)突变引起FQs药物较高水平耐药;GAC94GCC(Asp→Ala)和GCG90GTG(Ala→Val)突变引起FQs药物较低水平耐药。结论 LVF与MXF之间存在交叉耐药,MXF MIC随LVF MIC增高而增高,但耐药水平不同。GyrA基因突变位点可能与耐药水平有关,有可能根据基因突变的位点分析耐药水平。     

Molecular epidemiological study of hepatitis B virus in Thailand based on the analysis of pre-S and S genes.

Aims: This study was undertaken to determine the prevalence and characteristics of hepatitis B virus (HBV) genotypes, antigen subtypes, "a" determinant variants and pre-S gene mutations circulating on a large scale in Thailand. Methods: The sequences of the Pre-S1, Pre-S2 and S regions were determined in serum samples of 147 HBsAg and HBV DNA-positive subjects who had been enrolled from the nationwide seroepidemiological survey conducted on 6213 individuals in 2004. Results: The results showed that genotypes C, B and A accounted for 87.1%, 11.6% and 1.3%, respectively. The distribution of the HBV antigen subtypes was: adr (84.4%), adw (14.2%) and ayw (1.4%). Regarding the "a" determinant, 2/43 (4.65%) and 2/104 (1.92%) samples of vaccinated and non-vaccinated subjects, respectively, displayed mutations, all ofwhich were Thr126Asn. Sequencing analysis showed the pre-S mutations in 14 (9.5%) samples, with pre-S2 deletion as the most common mutant (4.1%) followed by pre-S2 start codon mutation (2.9%), both pre-S2 deletion and start codon mutation (2.0%), and pre-S1 deletion (0.7%). The pre-S mutations were associated with older age and higher mean serum HBsAg level. Conclusion: This study demonstrated that HBV genotype/subtype C/adr and B/adw were the predominant strains circulating in Thailand. The "a" determinant variants seemed to be uncommon, and might not be attributed to vaccine-induced mutation.     

Significance of the minor i and t determinants of hepatitis B virus in hepatocellular carcinoma

Stored sera from asymptomatic hepatitis B virus (HBV) carriers and hepatitis B virus surface antigen-positive hepatocellular carcinoma (HCC) patients were tested for HBV subtypes, such as subtype determinants d, y, w, r and also antigenic determinants isoleucine (i) and threonine (t) by direct S gene nucleotide sequencing. Significant changes in minor i and t determinants in hepatocellular carcinoma patients with adr hepatitis B carriers were seen. The adr subtype with t determinant was present in 14/25 (56%) of HCC patients compared with only two of 28 (7%) in asymptomatic hepatitis B carriers ( P < 0.001). However, the adr subtype with i determinant was present in nine of 25 (36%) of the HCC patients and also present in 24/28 (86%) of asymptomatic carriers ( P < 0.001). No significant changes were seen with the adw subtypes. These results show that i and t minor determinant changes are more common with adr subtypes associated with HCC than with the adw subtype. Whether these subtle changes are pathologically relevant or only a polymorphism of hepatitis B genotypes will depend on subsequent follow-up studies.     

Clustering of Different Subtypes of Hepatitis B Surface Antigen in Families of Patients with Chronic Liver Diseases

Clustering of hepatitis B surface antigen (HBsAg) with both subtypes adr and adw in three families of patients with chronic liver diseases or hepatocellular carcinoma was demonstrated in Taiwan where adw is the main subtype. The subtype in the children was similar to that in their mothers, suggesting maternal transmission. In all the family units clustered with different subtypes, the same pattern occurred, invariably with fathers carrying HBsAg/adr and the children carrying HBsAg/adw. The subtype difference clearly rules out the transmission of hepatitis B virus (HBV) from father. Horizontal infection with the locally dominant adw-subtyped HBV in the children of fathers carrying HBsAg/adr explains the discrepancy of the subtypes in these families. Clustering of two HBsAg-positive brothers with hepatocellular carcinoma in one of the families was found. That both adr-subtyped and adw-subtyped HBV are capable of inducing chronic active hepatitis in another family suggests that host factors are probably more important in determining the clinical course of HBV infection.     

A synthetic peptide vaccine involving the product of the pre-S(2) region of hepatitis B virus DNA: protective efficacy in chimpanzees.

The S gene encoding the major surface polypeptide of hepatitis B virus is preceded by the region pre-S(2) with a capacity to code for 55 amino acid residues. In the product of region pre-S(2), the sequence of 19 amino acid residues (amino acids 14-32 from the N terminus) representing an area of high local hydrophilicity is shared by viral strains of subtypes adr, ayw, and ayr; residue 22, phenylalanine, is replaced by leucine in a strain of the other subtype, adw. A synthetic peptide vaccine involving these 19 amino acid residues, when given to two chimpanzees, raised antibodies that bound to viral particles and protected the animals from challenge with 10(6) chimpanzee infectious doses of hepatitis B virus.     

Identification of hepatitis B virus vertical transmission from father to fetus by direct sequencing

To identify the possibility of hepatitis B virus (HBV) vertical transmission from father to fetus, eight male HBV carriers whose wives were negative for any HBV marker and their eight aborted fetuses who had been infected with HBV in utero, were studied. S gene 451 approximately 660 nucleotide sequence of HBV in 6 cases of father/fetus pairs and C gene 2022 approximately 2321 nucleotide sequence in the other 2 cases of father/fetus pairs were amplified by nested polymerase chain reaction (NPCR), and sequenced. HBV DNA was detected in the semen and spermatid of male HBV carriers. The homologies of HBV sequences between father and fetus were very high. Six father/fetus pairs had the same subtype adw. The sequences of the fragment were identical between father and fetus in 4 cases. Especially in case 3, both father and fetus had the same point mutation, which caused an amino acid substitution at codon 126. The other two cases had point mutations in the fetus at nucleotide positions 491, 494, 546, 581 resulting in amino acid substitution at codons 113, 114, 131, 143. The C gene 2022 approximately 2321 nucleotide sequences in two cases were identical. There were eleven common point mutations between father and fetus, but those mutations did not cause phenotypic changes. Our finding suggested that HBV vertical transmission from father to fetus was present. A HBV carrier father may transmit the virus to his fetus by spermatid.     

Neutralization epitope responsible for the hepatitis B virus subtype-specific protection in chimpanzees

Neutralizing monoclonal antibody (BX-182) directed against the d determinant of hepatitis B virus (HBV) surface antigen protected chimpanzees from infection by HBV subtype adw but not by subtype ayw, as demonstrated by intravenously inoculating a mixture of the antibody with the respective subtype of the virus. To elucidate the mechanism underlying the subtype-specific protection, a combinatorial approach of screening random peptide phage libraries, bioinformatics, and structure analysis was used in this study to identify the neutralization epitope responsible for the observed protection. The epitope was mapped at the N terminus of the pre-S1 region of the hepatitis B surface antigen between residues 17 and 21, of which the residues Val-18/Pro-19 were critical for antibody binding. Alignment of amino acid sequences derived from diverse genetic variants of HBV revealed that the epitope was present in ad subtypes and in their corresponding genotypes A, B, C, F, and H. By contrast, this epitope was not found in a majority of ay subtypes or in genotypes D, E, and G, where the antigenic residues Val-18/Pro-19 within the epitope were replaced by Thr/Ser, Thr/Thr, or Ala/Ser, respectively, resulting in a drastic conformational change of the epitope. These data indicate that, by binding discriminately to the subtype "d" epitope in the pre-S1 region, neutralizing antibody BX-182 protects chimpanzees from HBV infection in a subtype-specific manner, suggesting a potential escape mechanism for HBV genetic variants.     

Hepatitis B surface antigen disappearance and hepatitis B surface antigen subtype: a prospective, long-term, follow-up study of Japanese residents of Okinawa, Japan with chronic hepatitis B virus infection.

To determine the natural course of hepatitis B surface antigen (HBsAg) disappearance in chronic hepatitis B virus (HBV) infection and the factors related to its disappearance, 946 HBsAg carriers in Okinawa, Japan were prospectively followed for up to 19 years (mean = 9.2 years). The disappearance of HBsAg, as determined by radioimmunoassay (RIA), was observed in 62 (6.6%) and the overall annual disappearance rate was 0.79%/year. Its disappearance was more frequent in 60 (7.4%) of 815 serum samples negative for hepatitis B e antigen (HBeAg) by RIA at entry compared with only two (1.5%) of 131 serum samples that were HBeAg positive by RIA at entry (P < 0.05). Stepwise logistic regression analysis showed that age and HBsAg subtype were significantly associated with HBsAg disappearance (both P < 0.05), and that carriers with subtype adr (odds ratio = 2.87) had an increased probability of clearing HBsAg compared with carriers with subtype adw. Conversely, HBeAg disappearance was earlier in those with the adw subtype than in those with adr. Hepatitis B virus DNA was not detected by the polymerase chain reaction after HBsAg disappearance in any of the 62 from whom it had disappeared. The HBsAg titer, as measured by reverse passive hemagglutination, was related to the time to its disappearance; the higher the titer, the longer the time to disappearance. These findings suggest that HBeAg negativity, a more advanced age, and low titers of HBsAg are favorable factors for HBsAg disappearance in the natural course of chronic HBV infection. Moreover, HBsAg subtype adr was a predictive factor for HBsAg disappearance, whereas subtype adw was predictive of early HBeAg disappearance.     

HBV core sequence: definition of genotype-specific variability and correlation with geographical origin

There are eight genotypes and nine subtypes of HBV. Small differences in geographical origin are associated with sequence changes in the surface gene. Here, we compared core gene sequences from different genotypes and geographical regions. Specific combinations of 24 amino acid substitutions at nine residues allowed allocation of a sequence to a subtype. Six of these nine residues were located in different T cell epitopes depending on HBV geographical area and/or genotype. Thirty-seven nucleotide changes were associated uniquely with specific genotypes and subtypes. Unique amino acid and nucleotide variants were found in a majority of sequences from specific countries as well as within subtype ayw2 and adr. Specific nucleotide motifs were defined for Korean, Indian, Chinese, Italian and Pacific region isolates. Finally, we observed amino acid motifs that were common to either South-east Asian or Western populations, irrespective of subtype. We believe that HBV strains spread within constrained ethnic groups, result in selection pressures that define sequence variability within each subtype. It suggests that particular T cell epitopes are specific for geographical regions, and thus ethnic groups; this may affect the design of immunomodulatory therapies.     

Maternal transmission of hepatitis B surface antigen in patients with hepatocellular carcinoma in Taiwan

To determine the source of the highly prevalent hepatitis B virus (HBV) infection in our patients with hepatocellular carcinoma (HCC), we examined hepatitis B surface antigen (HBsAg) and its subtypes and antibody in 11 patients with HCC and their parents. All the patients were positive for HBsAg. Eight (73%) of the mothers were also HBsAg-positive, whereas only one of the seven fathers was an HBsAg carrier (P = 0.025). The observation is compatible with maternal transmission as a source of HBV infection in most of our patients with HCC. The subtype was identifiable in 10 patients, 9 with HBsAg/adw and one with adr. The subtype was identical in the patient--mother carrier pairs, suggesting that HBV infection in the patient and the mother is intimately related. This is further evidenced by the observation of a relatively uncommon adr subtype in one patient--mother pair. These observations suggest that the HBV infection in our patients results from vertical transmission from their carrier mothers probably long before the development of HCC.     

表面抗原和抗体双阳性慢性乙型肝炎病毒感染者病毒S基因的变异分析

目的 了解HBsAg和抗-HBs双阳性慢性HBV感染者的S基因变异情况.方法 分别对8例HBsAg和抗-HBs双阳性(实验组)及9例HBsAg阳性、抗-HBs阴性慢性HBV感染者(对照组)的S基因进行PCR扩增并测序,将测序结果进行对比分析.基因型和血清型分布比较、主要亲水区变异位点数比较采用Fisher'S精确检验,核苷酸和氨基酸序列的同源性比较采用t检验.结果 感染HBV的基因型分布:实验组为B型2例、C型6例,对照组为B型6例、C型3例,两组间差异无统计学意义(P>0.05);血清型分布:实验组为adw 2例、adr 5例、ayr 1例,对照组为adw 6例、adr 3例,两组间差异无统计学意义(P>0.05).实验组和对照组HBV前S1区的核苷酸替换率(2.29%比1.8%)和氨基酸替换率(2.66%比1.59%)差异无统计学意义(t值分别为1.56和1.39,P值均>0.05),前S2区的核苷酸替换率(1.74%比0.91%)差异有统计学意义(t=4.68,P<0.01),氨基酸替换率(3.18%比2.05%)差异无统计学意义(t=1.85,P>0.05);S区的核苷酸替换率(2.13%比0.81%)和氨基酸替换率(4.37%比1.52%)差异有统计学意义(t值分别为6.00和5.32,P值均<0.01).主要亲水区内外均存在氨基酸的替换,"a"决定簇变异相对较高(P<0.05).结论 HBsAg和抗-HBs双阳性慢性HBV感染者的S基因变异率相对较高.