The <Emphasis Type="Italic">Arg</Emphasis>194<Emphasis Type="Italic">Trp</Emphasis> polymorphism in DNA repair gene XRCC1 and the risk for sporadic late-onset Alzheimer's disease

Abstract Alzheimer's disease (AD) is defined pathologically by the presence of β-amyloid plaques, neurofibrillary tangles and extensive neuronal loss. Evidence indicates that increased DNA damage may contribute to neuronal loss in AD. Recently, it has been shown that in AD neurons have a reduced capacity for some types of DNA repair. Polymorphisms in DNA repair genes may be associated with differences in repair efficiency of DNA damage. Variants of several DNA repair genes, including the base excision repair gene XRCC1, have been described previously. We hypothesised that Arg194Trp polymorphism of XRCC1 gene may contribute to genetic susceptibility for AD. In order to test this hypothesis, we investigated Arg194Trp polymorphism at the XRCC1 gene in the DNA samples of 98 patients with AD and 95 healthy subjects. The frequency of the Trp allele was more pronounced among cases (11.2%) compared with controls (5.8%). On combining the homozygous and heterozygous variants of each codon, the variants seemed to be at twofold risk of AD, although the risk estimates were not statistically significant (OR=1.95, 95% CI 0.88–4.34, p=0.09). In addition, the 194Trp allele revealed a borderline significance (OR=2.05, 95% CI 0.96–4.37, p=0.056). According to our results, it may be speculated that the polymorphic variants of XRCC1 codon 194 have a role in the development of AD.     

Polymorphic distribution of Y-chromosome haplotype and mitochondrial DNA in the Bouyei people in China

In the evolution of humans, many kinds of mutations in the human genome have been accumulated, providing credible genetic evidence for the study of human origins and migrations. The "out-of-Africa" hypothesis of modern human evolution and the genetic origin of the Japanese has come about by studying mitochondrial DNA.l,2 Recently, researchers have recognized the power of Y-chromosome markers in resolving migratory patterns of modern humans as more and more Y-chromosome single nucleotide polymorphism markers have been found. The markers on the nonrecombinant part of the Y-chromosome allows for the reconstruction of intact haplotypes which are probably the best genetic tools to study human migrations. We can analyze the paternal history of some people in different areas by Y-chromosome haplotypes.     

日本血吸虫DNA疫苗研究进展

日本血吸虫病是一种严重危害人类健康的寄生虫病,目前,主要通过实施人畜吡喹酮为主的化疗来防治,但不能有效地防止再感染.日本血吸虫寿命长、危害大、动物宿主多,单一的药物不能阻断传播.     

单细胞凝胶电泳技术在生殖细胞DNA损伤检测中的应用

单细胞凝胶电泳技术(SCGE)是一种快速检测单个细胞DNA损伤的实验技术,在生殖细胞DNA损伤的检测中广泛应用。本综述系统介绍了SCGE在睾丸生精细胞、支持细胞、间质细胞、卵巢细胞以及卵母细胞等生殖细胞DNA损伤检测中的应用现状,并对SCGE在生殖毒性检测中的发展提出了展望。     

Observations on two members of the Swedish family with congenital dyserythropoietic anaemia,type III

Abstract: Two affected individuals of the Swedish family with CDA, type III, in which the disease is transmitted as an autosomal dominant character, were studied. Both cases displayed features hitherto undescribed in this family but described in patients with CDA, type III, in whom the inheritance may have been as an autosomal recessive character. Such features were: (a) haemosiderinuria, (b) grossly disorganised erythroblast nuclei, (c) differences in the ultrastructural appearances of individual nuclei within the same multinucleate erythroblast and (d) intraerythroblastic inclusions resembling precipitated globin chains. In both cases the giant mononucleate erythroblasts and the multinucleate erythroblasts had total DNA contents up to 28c (1c = haploid DNA content) and 48c respectively, and some DNA synthesising bi- and multinucleate erythroblasts contained one or more nuclei which were unlabelled with ³H-thymidine. These findings are similar to those in patients with the autosomal recessive type of disease. Thus no major phenotypic differences are yet apparent between cases of CDA, type III, with different patterns of inheritance. Analysis of the surface erythrocyte proteins of the 2 Swedish CDA, type III, patients with monoclonal antibodies recognising Band 3, glycophorins A, B, C and D, Rh, CD44, CD47, CD55, CD58, CD59, Lutheran, Kell, LW and acetylcholinesterase did not reveal any gross abnormality of expression of these proteins. A slightly altered expression of blood group antigens A and H was revealed by the lectins Dolichos biflorus and Ulex europaeus and the Mr of Band 3 as judged by SDS polyacrylamide gel electrophoresis was also slightly reduced, suggesting that there may be minor alterations in the degree of N-glycosylation of some red cell membrane constituents.     

涎腺腺样囊性癌氩离子激光流式细胞术分析及其临床意义

为探讨流式细胞术对涎腺腺样囊性癌的诊断和预后估计的价值，对４１例腺样囊性癌行流式细胞术分析。结果，平均ＤＮＡ指数为１．１７９，Ｓ期细胞比例为２９．４９％，细胞增殖指数为４２．６７％，均明显高于正常组织。异倍体检出率为７０．７３％。随着肿瘤的增大和恶性程度的增加，其异倍体率、ＤＮＡ指数和Ｓ期细胞比例值也相应增加。流式细胞术为涎腺腺样囊性癌的病理诊断和确定恶性程度提供了有效的辅助诊断措施，但尚不能判断预后。     

荧光定量聚合酶链反应在尖锐湿疣诊断中的应用

目的　探讨荧光定量聚合酶链反应 (FQ - PCR)对尖锐湿疣 (CA )的诊断价值。方法　 FQ- PCR检测病理确诊的 CA患者 36份标本和健康人 84份标本 ;FQ- PCR及病理诊断同期检测临床送检病例 2 73份标本 ,并做诊断性试验评价。结果　 36例病理确诊的 CA患者 HPV6和 HPV11的 DNA FQ- PCR全部阳性 ,平均拷贝数为 1.0× 10 7± 1.0× 10 2 / m l;84例健康人 FQ- PCR全部阴性 ,平均拷贝数为 3× 10± 2× 10 / ml。 FQ- PCR与病理诊断符合率为 10 0 % ,CA患者与健康人拷贝数的差异有显著性 (P<0 .0 5 )。FQ- PCR与病理诊断对比得出 :灵敏度为 10 0 % ,特异度为 92 % ,误诊率为 0 .0 8,漏诊率为 0 ,准确度为 98.9% ,阳性预测值为 98.8% ,阴性预测值为 10 0 % ,阳性似然比为 12 .5 ,阴性似然比为 0。结论　 FQ - PCR能准确定量 ,灵敏度高 ,特异性强 ,快速 ,简便 ,可作为尖锐湿疣早期诊断的指标     

Detection of a human chromosomal translocation t(8;9) in a baby with multiple malformations using two-color fluorescence in situ hybridization

A human chromosomal translocation t(8;9) was detected using two-color fluorescence in situ hybridization with probes capable of staining the entire lengths of each of these chromosomes. The chromosome 8 probe was labeled with biotin and detected with Texas red, while the chromosome 9 probe was labeled with AAF and detected with FITC . In normal metaphase spreads, two metaphases from the proband, two red, one green and one part red and part green derivative chromosome were seen. The bicolor chromosome corresponded to translocation of a chromosome 8 segment to the distal part of the q region of one chromosome 9, as originally indicated by banding analysis. In interphase nuclei of the proband, four domains with bright fluorescence were recognized in many nuclei. Two were red, one was green, and the fourth had portions of both colors, indicating the presence of the translocation.     

Quantitative analysis of spermatogenic DNA synthesis in the rat using a monoclonal anti-5-bromodeoxyuridine antibody

Summary. The utility of the 5-bromodeoxy-uridine (BrdUrd) labelling technique for the quantitative analysis of spermatogenic deoxyribonucleic acid (DNA) synthesis was investigated in the rat. Rat testicles were labelled by a single intraperitoneal injection of 100 mg kg⁻¹ of BrdUrd. The testicles were removed 1 h after injection, fixed in Bouin's fluid and embedded in paraffin. BrdUrd-labelled cells were detected by immunohistochemical staining using a monoclonal anti-BrdUrd antibody. The number of BrdUrd-labelled tubules per total number of tubules (percent L.T.), the number of BrdUrd-labelled cells per total number of tubules (tubular ratio) and the number of BrdUrd-labelled cells per number of Sertoli cells (Sertoli cell ratio in BrdUrd-labelled cells) were calculated as indices of spermatogenic DNA synthesis during each stage of the seminiferous epithelial wave. BrdUrd labelling was found exclusively in the nuclei of spermatogonia and in preleptotene spermatocytes in the seminiferous epithelium. The percent L.T. was generally greater than 50%, except in stages VI, VII and XIV, and the tubular as well as Sertoli cell ratios in BrdUrd-labelled cells was greater than 2.0 and 0.15, respectively, in stages I, II-III, V, VIII, X, and XII. The tubular ratio and Sertoli cell ratio in BrdUrd-labelled cells along the seminiferous epithelial wave had two distinct peaks. The distribution of the tubular ratio using the BrdUrd-labelling technique correlated well with the distribution previously established by measuring tritiated thymidine uptake per tubule. Thus, the BrdUrd labelling technique, which is more efficient than the tritiated thymidine labelling technique, can be used to quantitatively evaluate spermatogenic DNA synthesis.