Differentiation of Helicobacter pylori isolates by polymerase chain reaction-restriction fragment length polymorphism

Objective: To investigate the association between the diversity of urease gene and urease activity of clinical isolates of Helicobacter pylori (H. pylori). Methods: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of urease gene and rapid urease activity test were used to study the urease activity of different clinical isolates of H. pylori. Results: H. pylori clinical isolates were divided into 4 types according to their PCR-RFLP results of urease gene and urease activity. Type Ⅰ , possessing strong urease activity (0. 11) and presented 1 fragment of 1. 7 kb by PCR-RFLP, had close relations with gastric ulcer; type Ⅱ , with the weakest urease activity (0. 07) and 2 fragments (1. 3 and 0. 4 kb respectively) , was associated with duodenal bulb ulcer; type Ⅲ , with the strongest urease activity (0. 12) and 2 fragments (0. 4 and 0. 17 kb) with or without 1 fragment (0. 23 or 0. 37 kb) , was responsible for gastritis; type Ⅳ , with weak urease activity (0. 09) and 2 fragments (1. 5 and 0. 2 kb), was shown to be related to both gastric and duodenal bulb ulcers. Conclusion: The diversity of urease gene decides different urease activities of different clinical isolates of H. pylori, hence the different possibilities of pathogenesis due to this bacteria.

Research on the Correlation Between rs2110385 Polymorphisms of the Visfatin Gene and Nonproliferative Diabetic Retinopathy

Objective:To investigate the association between rs2110385 polymorphisms of the visfatin gene and the risk of type 2 diabetic retinopathy(DR).Methods:172 Han subjects were selected from Xi’an Shaanxi Province;140 patients with type 2 diabetes mellitus(T2DM)and 32 normal controls(NC)were selected from our hospital.Patients with diabetes were divided into a non-DR group(T2DM)(n=69)and a nonproliferative diabetic retinopathy Group(DR)(n=71)after dilated fundus photography and fundus fluorescein angiography.rs2110385/AluⅠgenotypes were detected by standardized polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP),and the differences in the detection rates of different genotypes in the above populations were compared.Results:1)The visfatin level in the DR Group was significantly higher than that in the NC and T2DM groups(P<0.05).2)The frequency of GG genotype and G allele of rs2110385 in the DR Group were higher than those in the T2DM and NC groups(80.3,69.6,50.0,86.6,79,65.6,P<0.05).3)There were significant differences in allele frequency and genotype frequency distribution of rs2110385 between the DR Group and the NC group(P<0.01).Conclusion:Visfatin increased in the nonproliferative diabetic retinopathy group and could be a potential indicator for the clinical prediction of DR.The G allele of the rs2110385 polymorphic site may be related to the risk of DR.

Association of TNF-α-238G/A and 308 G/A Gene Polymorphisms with Pulmonary Tuberculosis among Patients with Coal Worker’s Pneumoconiosis

Objectives Tumor necrosis factor-α （TNF-α） may play an important role in host＇s immune response to mycobacterium tuberculosis （M. tuberculosis） infection. This study was to investigate the association of TNF-α gene polymorphism with pulmonary tuberculosis （TB） among patients with coal worker＇s pneumoconiosis （CWP）. Methods A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-α gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism （PCR-RFLP）. Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher＇s exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplieative model with combined OR. All data were analyzed using SAS version 8.2 software. Results No significant difference in frequency of the TNF-α-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls （2,2=5.44, P=-0.07）. But difference in frequency of the TNF-α-308 A allele was identified between them （2,2-5.14, P=0.02）. No significant difference in frequencies of the TNF-α-238 genotype and allele （P=0.23 and P=0.09, respectively） was found between cases and controls either, with combined （GG and AA） OR of 3.96 （95% confidence interval of 1.30-12.09） at the -308 locus of the TNF-α gene, as compared to combination of the TNF-α-238 GG and TNF-α-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-α-238 GG and TNF-α-308 GA genotypes was 1.98 （95% CI of 1.06-3.71） for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-a-308 GG genotype and body mass index （OR=4.92）, as well as an interaction between the TNF-α-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-α-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated. Conclusions TNF-α-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-α-238 A allele was otherwise.

细胞色素CYP2E1和GST M1与肺癌易感性的病例对照研究

目的 探讨谷胱甘肽转硫酶 (GST)和细胞色素CYP2E1多态性与肺癌易感性的关系。方法 选取广州市广东籍新发肺癌病人 91例及同期非肺部疾患及相同性别的病人 91例作匹配 ,调查他们的吸烟、饮酒等因素的暴露情况。用聚合酶链式反应 (PCR)和限制性片段长度多态性 (RFLP)技术检测CYP2E1和GST的基因多态性。结果 CYP2E1C1C1基因型与C1C2基因型比较 ,其OR为 1.82 (95 %CI =0 .95～ 3.4 0 ) ,GSTM 1基因缺失型的OR值为 1.2 6 (0 .6 9～ 2 .30 ) ,而两者联合分析时 ,则可增加患肺癌的危险 ,其OR值为 2 .13(0 .82～ 5 .5 6 ) ,但无统计学意义 (P >0 .0 5 )。吸烟与肺癌关系密切 ,其OR值为 2 .82(1.5 6～ 5 .12 ) ,当吸烟与这两种基因型协同作用时 ,可明显提高患肺癌的危险性 ,携带CYP2E1C1C1基因型的吸烟者的OR值为 5 .4 2 (2 .0 5～ 14 .32 ) ,GSTM1基因缺失型的吸烟者的OR值为 4 .38(1.81～ 10 .6 1)。多因素logistic回归分析结果表明 :文化程度 (OR为 0 .6 3,0 .4 5～ 0 .86 )、吸烟量 (OR为 1.5 6 ,1.14～ 2 .14 )、无抽油烟机 (OR为 3.77,1.4 8～ 9.5 6 )、食用动物油(OR为 1.6 7,1.2 5～ 2 .2 4 )、胡萝卜 (OR为 0 .4 7,0 .2 2～ 0 .98)、饮酒 (OR为 6 .5 8,1.5 3～ 2 8.3)、直系亲属肺癌史 (OR为 3.75 。

肝细胞癌Rb基因缺失的研究

应用PCR－RFLP技术检测了24例肝细胞癌抑癌基因Rb杂合缺失，发现25％（3／12）的肝细胞癌存在内含子1的缺失。同时用Rb基因cDNA为探针Southern杂交检测了10例肝细胞癌，发现2例分别在4．5Kb和9．8Kb，7．5Kb处缺失。所有发生Rb基因缺失的肝癌均为进展期。该结果表明：抑癌基因Rb的缺失可能参与了肝癌的进展过程。

育龄妇女雌激素受体β基因RsaⅠ多态性调查

目的 雌激素受体 β是一种核调节蛋白 ,其介导雌激素发挥多重作用。雌激素受体 β基因突变与某些疾病的发生有关 ,本文调查了雌激素受体基因RsaⅠ突变在女性人群中的分布。方法 采用PCR -RFLP方法检测ER β基因第 5外显子 1 0 82位核苷酸G -A突变。结果 1 0 1名女性人群中 ,ERβ基因RsaⅠ纯合突变型基因的频率为 9 9% ,杂合突变型基因的频率为 4 4 5 5 % ,野生型基因的频率为 4 5 5 5 % ,R等位基因的频率为 32 1 8,r等位基因的频率为 6 7 82 %。结论 陕西农村女性人群ERβ基因RsaⅠ多态性高于德国、新加坡妇女的突变率。需进一步研究该基因突变与疾病的相关性。

Aerobic biodegradation of di-n-butyl phthalate by Xiangjiang River sediment and microflora analysis

Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently,the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d,generating two main degraded products:mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP,the dominant family in the final enrichment culture is clustered with the Comamonas sp.,the remaining are affiliated with Sphingomonas sp.,Hydrogenophaga sp.,Rhizobium sp.,and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.

Is type Ⅰ alpha 2 collagen gene responsible for intracranial aneurysm in Northeast China?

In this study, we investigated whether a single nucleotide polymorphism （rs42524 G 〉 C） in the type I alpha 2 collagen gene was associated with sporadic ruptured intracranial aneurysm or its clinical characteristics in patients from Northeast China. Genotyping of the rs42524 G 〉 C polymorphism was carried out using a polymerase chain reaction-restriction fragment length polymorphism assay. The data showed that the frequency of the rs42524 GC ＋ CC genotype was significantly higher than the GG genotype among intracranial aneurysm patients whose Hunt and Hess grading scale was 〉 3. In addition, the rs42524 G 〉 C genotype was found to have a statistically significant association with intracranial aneurysm risk. These findings indicate that the type I alpha 2 collagen gene gene may be involved in a predisposition to intracranial aneurysm in the Northeast Chinese population. Crucially, the rs42524 C allele may be an important risk factor for increased severity of the condition in patients with ruptured intracranial aneurysms.

Mutational analysis of Ras hotspots in patients with urothelial carcinoma of the bladder

BACKGROUND Mutational activation of Ras genes is established as a prognostic factor for the genesis of a constitutively active RAS-mitogen activated protein kinase pathway that leads to cancer.Heterogeneity among the distribution of the most frequent mutations in Ras isoforms is reported in different patient populations with urothelial carcinoma of the bladder(UCB).AIM To determine the presence/absence of mutations in Ras isoforms in patients with UCB in order to predict disease outcome.METHODS This study was performed to determine the mutational spectrum at the hotspot regions of H-Ras,K-Ras and N-Ras genes by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP)and DNA sequencing followed by their clinical impact(if any)by examining the relationship of mutational spectrum with clinical histopathological variables in 87 UCB patients.RESULTS None of the 87 UCB patients showed point mutations in codon 12 of H-Ras gene;codon 61 of N-Ras gene and codons 12,13 of K-Ras gene by PCR-RFLP.Direct DNA sequencing of tumor and normal control bladder mucosal specimens followed by Blastn alignment with the reference wild-type sequences failed to identify even one nucleotide difference in the coding exons 1 and 2 of H-Ras,NRas and K-Ras genes in the tumor and control bladder mucosal specimens.CONCLUSION Our findings on the lack of mutations in H-Ras,K-Ras and N-Ras genes could be explained on the basis of different etiological mechanisms involved in tumor development/progression,inherent genetic susceptibility,tissue specificity or alternative Ras dysfunction such as gene amplification and/or overexpression in a given cohort of patients.

Detection of genotypic clarithromycin-resistant Helicobacter pylori by string tests

AIM: To evaluate the utility of the string test to detect genotypic clarithromycin-resistant Helicobacter pylori (H. pylori) by polymerase chain reaction (PCR)-restriction fragment length polymorphism.

PCR-RFLP and AP-PCR of rbcL and ITS of rDNA Show That × Taxodiomeria peizhongii （ Taxodium × Cryptomeria） Is not an Intergeneric Hybrid

Taxodiorneria peizhongii Z. J. Ye, J. J. Zhang et S. H. Pan was regarded as a new Intergenerlc hybrid between Taxodlum mucronatum Tenore （as the female donor） and Cryptomeria fortunei Hoolbrenk ex Otto et Dletr （as the male donor）. To confirm the authenticity of the intergeneric hybrid, we analyzed the rbcL gene and the Internal transcribed spacer （ITS） of 26S-18S ribosomal RNA gene of the three species using polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） and arbitrarily primed PCR （AP-PCR）, and ob- tained the following results：i） Taxodiomeria peizhongii had the same RFLP maps of the rbcL gene and the ITS as Taxodlum mucronatum, but was different from C. fortunei; II） a 311-bp PCR amplification product was obtained In C. fortunei by AP-PCR of ITS, but was not found in Taxodiomeria peizhongii. Our results have demonstrated that C. fortunei did not provide any genome for Taxodiomeria peizhongii, Implying that T. peizhongii Is not an Intergenerlc hybrid between the two species.

Glacial Refugia of Ginkgo biloba and Human Impact on Its Genetic Diversity:Evidence from Chloroplast DNA

Variations in the trnK region of chloroplast DNA were investigated in the present study using polymerase chain reactionrestriction fragment length polymorphism to detect the genetic structure and to infer the possible glacial refugia of Ginkgo biloba L. in China. In total, 220 individuals from 12 populations in China and three populations outside China were analyzed, representing the largest number of populations studied by molecular markers to date. Nineteen haplotypes were produced and haplotype A was found in all populations. Populations in south-western China, including WC, JF, PX, and SP, contained 14 of the 19 haplotypes and their genetic diversity ranged from 0.771 4 to 0.867 6. The TM population from China also showed a high genetic diversity （H = 0.848 5）. Most of the genetic variation existed within populations and the differentiation among populations was low （GsT = 0.2）. According to haplotype distribution and the historical record, we suggest that populations of G. biloba have been subjected to extensive human impact, which has compounded our attempt to infer glacial refugia for Ginkgo. Nevertheless, the present results suggest that the center of genetic diversity of Ginkgo is mainly in south-western China and in situ conservation is needed to protect and preserve the genetic resources.