儿童脊肌萎缩症运动神经元生存基因缺失分析

目的评价聚合酶链反应-限制性片段长度多肽性（PCR-RFLP）分析技术在脊肌萎缩症（SMA）临床诊断中的价值，分析端粒侧运动神经元生存基因（SMNt）表达与SMA临床分型之间的关系。方法对临床拟诊为SMA的23例患儿同时采用临床诊断标准和PCR-RFLP分析技术进行诊断，两种结果对比，分析灵敏度、特异度、Kappa值及P值。结果（1）临床诊断与PCR-RFLP基因诊断结果比较：23例拟诊患儿中临床确诊为SMA者18例，非SMA者5例。PCR-RFLP技术检测结果：5例非SMA者，SMNt基因检测均无缺失；18例确诊SMA者，SMNt基因缺失者15例，无SMNt基因缺失者3例，缺失频率为83．3％。此方法的灵敏度为83．3％，特异度为100％，阳性预测值100％，阴性预测值62．5％，真实性为86．96％，Kappa值为0．685。（2）SMA不同临床分型中SMNt基因7、8号外显子缺失检测结果：Ⅰ型患者以7、8号外显子缺失为主，SMNt基因缺失频率100．0％；Ⅲ型患者以7号外显子缺失为主，SMNt基因缺失频率为66．7％；Ⅰ型患者7、8号外显子联合缺失频率较Ⅲ型高（P〈0．05）。结论（1）PCR-RFLP分析技术简便、快捷、特异性高，敏感性好，适用于临床儿童型SMA的基因诊断，尤其对于SMAI型患者。（2）SMNt基因7、8号外显子联合缺失常常提示病情严重，预后不良；单独缺失提示病情较轻，预后较好。     

中外六个猪种FUT1基因多态性研究

目的对6个中外猪种共245头猪的FUT1基因进行了研究。方法采用PCR-RFLP技术。结果与结论Hin6I位点上，大白猪、长白猪、杜洛克猪3个外来猪种均存在多态，且以敏感型（GG型和AG型）居多；山西黑猪、太原花猪、马身猪3个本地猪种的所有检测样品都表现为GG型。     

急性白血病病人ECR1基因多态性与红细胞免疫功能的关系

目的:探讨急性白血病病人红细胞补体受体Ⅰ型分子(ECR1)基因密度多态性与红细胞免疫黏附功能的相关性。方法:急性白血病46例,正常对照50例,采用PCR-RFLP法测定RBC-CR1基因型。以红细胞黏附花环试验测定RBC-C3b受体花环率(RBC-C3bRR)及免疫复合物花环率(RBC-C ICR)。结果:①与对照组比,急性白血病病人RBC-C3bRR下降,RBC-C ICR上升(P<0.01);②急性白血病病人HH型、HL型LL型分别是60.87%、30.44%、8.69%,突变率是39.13%,与对照组相比无统计学意义(P>0.05);③在急性白血病组内,HL型的RBC-C3bRR为17.23±5.74,低于HH型的26.06±6.21;RBC-C ICR为7.36±2.45,高于HH型的4.63±2.00,其差异有统计学意义(P<0.01)。结论:急性白血病病人RBC免疫功能低下,ECR1基因缺陷对病人的RBC免疫能力下降有一定影响。不同ECR1基因型的人群红细胞免疫功能有差异,HH型的红细胞免疫黏附功能强于HL型。     

重庆地区汉族人群CD14基因启动子区-159 T→C多态性及其与LPS反应分析

目的观察重庆地区汉族人群CDl4基因启动子区-159单核甘酸多态性（single nucleotide polymorphism，SNP）分布特征，及其与CDl4表达和脂多糖（1ipopolysaccharide，LPS）反应的关系。方法选择298例重庆地区汉族健康个体，采用限制性片段长度多态性法（restrictionfragment lengthpoly-morphism，RFLP）进行基因分型，检测LPS刺激前后外周血单核．巨噬细胞mCDl4荧光强度和血浆sCDl4浓度。结果重庆地区汉族人群CD14—159T／T、T／C、C／C基因型频率分别为32．21％、50．67％和17．11％，样本符合Hardy．Weinberg平衡，正常情况下，不同基因型mCD14水平差异不明显，而sCD14浓度有显著性差异（P＜0．05），LPS刺激能增强mCD14和sCD14的表达，但各基因型的增强幅度没有明显差异。结论重庆地区汉族人群CD14—159SNP等位碱基以T为主，T→C变异可抑制sCD14的表达，但对mCD14表达和LPS刺激反应的影响可能不明显。     

Improvement in HLA-DQB typing by PCR-RFLP: Introduction of a constant restriction site in one of the primers for digestion control

The PCR-RFLP method previously reported by Inoko is a powerful technique for HLA class II typing. The reliability of RFLP interpretation depends on complete digestion by restriction endonucleases using a modified primer with restriction sites as an internal digestion control. The use of restriction enzymes which recognize specific HLA DQB allelic variations makes HLA DQB genotyping possible.     

Polymorphism of the human retinoid X receptor beta and linkage disequilibrium with HLA-DPB1

The human retinoid X receptor beta (RXRB) gene is localized in the major histocompatibility complex (MHC) region between DPB1 and RING2. The RXRB gene sequence reported by different investigators suggests that the gene may be polymorphic. In this study, we confirmed one polymorphism by sequencing genomic DNA from four Caucasian individuals. We also developed a restriction fragment length polymorphism (RFLP) analysis to detect this specific polymorphism. Linkage analysis studies between RXRB alleles and a number of HLA markers showed significant linkage disequilibrium between RXRB*T and HLA-DPB1*0401.     

Genotyping of Hepatitis C virus (HCV) in infected patients from South India

Hepatitis C virus shows substantial nucleotide sequence diversity distributed throughout the viral genome. In the present study genotyping for Hepatitis C virus (HCV) infected patients was based on RFLP analysis of 5' UTR and using type specific primers of NS5B regions. It was observed that 60% of the patients (30 patients with chronic hepatitis) were infected with variants of genotype 1 and 40% of the patients (4 chronic hepatitis patients, 12 patients with chronic renal failure and 4 cirrhosis) were infected with variants of type 3 of HCV. None of the cirrhotic patients and patients with chronic renal failure, in the present study, were infected with type 1 of HCV. While PCR-RFLP, typing was rapid in conjunction with the primers used for RT-PCR, NS5 typing was helpful in determining the subtype. There was good correlation between the two typing methods and this method can be used as a cost-effective method for studying large number of samples. The study shows that predominant genotypes of HCV in South India include type 1 and 3. Type 3 seems to be transmitted nosocomially as suggested by the results in patients with chronic renal failure, as these patients are exposed to multiple medical interventions.     

Identification and phylogenetic relationship of Iranian strains of various Leishmania species isolated from cutaneous and visceral cases of leishmaniasis based on N-acetylglucosamine-1-phosphate transferase gene

The identity of Iranian Leishmania species has been resolved to some extent by some genetic markers. In this study, based on N-acetylglucosamine-1-phosphate transferase (nagt) gene, we further elucidated the identity and phylogeny of the prevalent species in this country. DNAs of 121 isolates belonging to cutaneous leishmaniasis (CL) patients, canine visceral leishmaniasis (CVL) cases, and Rhombomys opimus rodents were amplified by targeting a partial sequence of nagt gene. All the amplicons were analyzed with restriction fragment length polymorphism (RFLP) using Acc1 enzyme, and 49 amplicons representing different reservoir hosts were sequenced and aligned with similar sequences from GenBank database. The RFLP analysis revealed that 41 CL patients were infected Leishmania tropica and 36 with Leishmania major. Among 10 CVL isolates, 6 were identified as Leishmania infantum and 4 as L. tropica. Amongst 34 rodents’ isolates, 11 and 23 isolates exhibited patterns similar to those of L. major, and L. tropica/Leishmania turanica, respectively. The sequencing results from all CL patients, CVL cases, and 4 reservoir rodents were in agreement with RFLP analysis and showed 99–100% homologies with the registered species of L. major, L. tropica, and L. infantum from Turkey, Tunisia, Iraq and Israel. Of the 7 rodent isolates exhibiting RFLP patterns similar to L. tropica/L. turanica, 3 exhibited the highest homologies (99–100%) with L. turanica and 4 with Leishmania gerbilli. The 49 nagt DNA sequences were grouped into five clusters representing L. major, L. tropica, L. infantum, L. turanica and L. gerbilli species, encompassing 19 haplotypes. No correlation was observed between intraspecies divergence and geographic distribution of haplotypes. The L. tropica haplotypes exhibited more homologies with those of L. infantum than L. major (97.2% vs. 96.9%), a probable indication to the potential ability of L. tropica to visceralize. Characterization of Iranian Leishmania isolates using nagt gene allowed unambiguous identification of five prevalent species with a high-resolution phylogeny.     

Typing of sandflies from Greece and Cyprus by DNA polymorphism of 18S rRNA gene

A simple and reliable technique was developed to distinguish Phlebotomine sandflies by restriction fragment length polymorphism of PCR-amplified (PCR-RFLP) 18S rDNAs. Seven morphologically identified sandflies species from several localities of Greece and Cyprus were studied, and specific patterns were developed by double digesting amplified 18S rDNAs with Hpall and Rsal. Three additional species of the sub-genus Larroussius were distinguished by a second double digestion with Accl and Banl. We have successfully applied the method on samples in which morphological characters were badly distinguished due to poor storage conditions and in larval stages.     

多浪羊和中国美利奴羊MHC-DRB1基因多态性与包虫病的遗传易感性

目的探讨多浪羊和中国美利奴(新疆军垦型)羊MHC-DRB1基因的多态性与包虫病的遗传易感性。方法利用巢式PCR扩增192只多浪羊和199只中国美利奴(新疆军垦型)羊(其中各有70只和98只为棘球蚴病感染——包虫病阳性)MHC-DRB1基因第二外显子,其296bp扩增产物经SacI、Hin1I和HaeIII3种限制性内切酶进行RFLP多态性分析。结果多浪羊和中国美利奴羊的MHC-DRB1基因第二外显子在SacI、Hin1I和HaeIII酶切位点存在丰富的多态性,两绵羊品种均检测出了2、2和6种等位基因,但基因型分别为3、3、18和3、3、15种。DRB1第二外显子的第159,173,177,178,208,225位碱基上存在多态性。结论将两绵羊品种包虫病阴性和阳性羊的等位基因频率和基因型频率分别进行了分析比较,结果提示多浪羊等位(基因HaeIII a与包虫病的易感性相关(P<0.05);基因型SacI ab和HaeIII cf与包虫病的抗性相关(P<0.05),SacI bb,Hin1I ab和HaeIII aa 3种基因型与包虫病的易感性相关(P<0.05),而基因型HaeIIIbe和HaeIII ef与包虫病的易感性具有较强的相关性(P<0.01)。中国美利奴(新疆军垦型)羊等位基因HaeIII d与包虫病的易感性相关(P<0.05);基因型SacI ab和HaeIII ee与包虫病的抗性相关(P<0.05),而基因型HaeIII bd与包虫病的易感性相关(P<0.05)。