共查询到20条相似文献,搜索用时 15 毫秒
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目的:探讨TIMP-3基因甲基化与结直肠癌临床病理指标和转移复发的关系。 方法: 采用巢式甲基化特异性PCR技术(nMSP法)检测100例结直肠癌组织和100例癌旁非癌组织TIMP-3基因甲基化;采用RT-PCR检测100例结直肠癌组织和100例癌旁非癌组织TIMP-3 mRNA的表达。 结果: 肿瘤组织TIMP-3 mRNA的表达阳性率为64%,肿瘤组织TIMP-3 mRNA的表达率明显低于癌旁非癌组织(P<0.01);TIMP-3 mRNA的表达率无淋巴结转移组(34/42)高于淋巴结转移组(30/58)(P<0.01),甲基化阳性率Duke’s C+D期伴淋巴结转移组明显高于Duke’s A+B期不伴淋巴结转移组(P<0.05)。结肠近端、分化程度差的结直肠癌组织甲基化阳性率明显高于远端直肠和分化程度高者(P<0.05)。 结论: TIMP-3基因甲基化容易发生在结肠近端、Duke’s C、D期、伴淋巴结转移、细胞分化差和浸润型结直肠癌患者。 相似文献
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目的:观察在免疫球蛋白的类别转换(CSR)过程中单个转换区(S区)的基因重组情况.方法:通过构建包含单个S区(FSα-2)基因序列的人工载体,使目的基因位于四环素敏感的启动子下游,并转染到一株能够在体外诱导CSR反应的B淋巴细胞系,经细胞因子诱导CSR后,用PCR扩增目的基因,再进行序列分析以观察此S区基因的变异及其依赖的因素.结果:在细胞因子的诱导下,单个S区基因在CSR时可以出现基因变异包括点突变、序列缺失及序列插入等变化,并且当抑制上游启动子时,S区基因变异显著下降,表明S区基因重组受控于基因转录.结论:CSR重组机制在单个S区中同样发挥作用. 相似文献
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Christian Huber Erwin Huber Andrea Lautner-Rieske Karlheinz F. Schble Hans G. Zachau 《European journal of immunology》1993,23(11):2860-2867
The L regions are parts of the Cχ proximal (p) and distal (d) copies of the human immunoglobulin x locus and are therefore called the Lp and Ld regions. The two regions with their 25 Vχ genes and pseudogenes have now been cloned, thus completing the cloning of the x locus. Lp has been linked to the neighboring Ap and B regions, while Ld was linked to Ad. There is good evidence that at the other side of Ld, i.e. towards the centromere, the end of the locus has been reached. Most of the cloning and linking was achieved by chromosomal walking, employing cosmid and phage λ clones. No such clones could be found for three small gaps. Two of them were closed by a polymerase chain reaction strategy; the third one was characterized by genomic blot hybridization experiments and eventually bridged by a yeast artificial chromosome clone. Early in evolution, a stretch of about 25 kb which comprised three VK genes near the 5′ end of the L region precursor must have been duplicated, such that the later duplication of large parts of the x locus resulted in the appeareance of two very similar three-gene regions in each, Lp and Ld. Two deletions in the central parts of the L regions, on the other hand, must have occurred after the duplication of the locus, since they are found in Lp and Ld in different positions. 相似文献
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To provide the building blocks for making synthetic antibody fragments we have used the polymerase chain reaction (PCR) to clone human variable (V) gene segments of λ light chains. The PCR primers were based on the sequences of known human Vλ segments, and were used to isolate 14 new Vλ segments (including 4 pseudogenes) from a single individual. We have compiled a sequence directory from this data and other sources to include all known human Vλ segments with open reading frames and we have identified a new Vx family (Vλ IX). Almost all of the segments (22/24) have different sequences in the complementarity-determining regions, setting a lower limit to the structural diversity of the antigen binding sites encoded by human Vλ genes in the human population. 相似文献
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The differentiation of memory B cells in germinal centers (GC) is selectively enhanced upon administration of antigen-antibody complexes. To characterize the repertoire of this response, we examined the rearranged immunoglobulin heavy chain variable (VH) genes from mouse splenic GC after a single immunization with either antigen, nitrophenyl (NP) hapten coupled to keyhole limpet hemocyanin, or with a preformed complex of antigen with a monoclonal anti-NP antibody of γ1 isotype. Among antigen-immunized mice, NP-reactive GC B cell populations in the antigen-induced GC consisted mostly of cells expressing the canonical V186.2 gene which contained, on average, 0.8 point mutations/VH gene by day 8 after immunization. These results are indicative of the beginning of somatic hypermutation and consistent with previously published analyses of NP antigen-driven GC. In contrast, the NP-specific B cells in GC that were elicited by administration of immune complex represented a heterogeneous cell population expressing nine different germ-line segments of the V186.2/V3 (J558) gene family, i.e. V23, V24.8, C1H4, V3, CH10, V165.1, V102, V671.5 and V186.2. Moreover, the average frequency of mutations in these genes was 1.7, reaching up to 4 mutations/VH in some GC. Administration of the antigen NP in complex with specific antibody apparently alters the process of interclonal competition in the GC and results in loss of dominance by V186.2+ cells and nearly stochastic representation of diverse clono-types. These results suggest an important feedback regulation of the B cell repertoire by antibody and indicate a role for immune complexes in the activation of somatic hypermutation. 相似文献
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Thomas Kirschbaum Soheil Pourrajabi Ines Zocher Jürgen Schwendinger Verena Heim Franz Rschenthaler Verena Kirschbaum Hans G. Zachau 《European journal of immunology》1998,28(5):1458-1466
A detailed restriction map of a 430-kb contig comprising the single Cκ, the 5 Jκ and the adjoining 22 Vκ gene segments is presented. The first 12 Vκ genes following the JκCκ region belong to the Vκ21 family, the subsequent ones to the closely related families Vκ8 and Vκ19/28. Previous difficulties in cloning all Vκ21 genes can now be explained by the presence of a duplicated region in this part of the locus. The structure was established by analysis of yeast artificial chromosome, bacterial artificial chromosome and cosmid clones and by the so-called long template PCR technique. The distance between Cκ and the proximal Vκ21 gene is 22 kb and the average distances between the Vκ genes are about 20 kb. Of the 12 Vκ21 genes 5 were sequenced for the first time and 8 of the 12 genes were found to be expressed. Of the 10 Vκ8 and Vκ19/28 germline genes 9 are new; expression products of 8 of the 10 genes were known. The known 5 ′ , 3 ′ polarities allow to specify for the 22 Vκ genes whether they are rearranged to the JκCκ element by a deletion or an inversion mechanism. Also the formation of interesting rearrangement products in classical cell lines as MPC11, MOPC41 and PC 7043 can be explained now. The non-Vκ sequence L10 whose rearrangement by inversion has been described earlier (Hoechtl and Zachau, Nature 1983. 302:260 – 263) was now localized downstream of JκCκ. 相似文献
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《Pathology, research and practice》2020,216(5):152914
DNA methylation is one of the epigenetic mechanisms to regulate gene expression and frequently occurs in human cancer cells. T-cadherin (CDH13) is a new member of the cadherin superfamily and possesses multiple functions. Our study included 26 normal controls (NCs), 65 chronic hepatitis B patients (CHB), 14 liver cirrhosis patients (LC) and 157 hepatocellular carcinoma patients (HCC). We mainly focused on the mRNA expression and methylation status of CDH13 in peripheral blood mononuclear cells (PBMCs), which were detected by semi-quantitative real-time polymerase chain reaction (RT-qPCR) and methylation-specific polymerase chain reaction (MSP) respectively. The CDH13 mRNA level was lower in HCC, especially in early-stage of HCC than in NCs and CHB groups (p < 0.05). Methylation frequency of the CDH13 promoter was significantly higher in HCC patients than in the NCs and CHB groups (67.52 % vs 0.00 %, p < 0.001, 67.52 % vs 52.31 %, p < 0.05, respectively). CDH13 mRNA level was significantly and relatively lower in methylated groups than in unmethylated groups among the whole participants. The methylation level of CDH13 promoter in HCC might be influenced or partly influenced by some critical factors such as TBil, ALB and AFP (p < 0.05). As an important factor in signaling pathway regulating by CDH13 to promote carcinogenesis, JNK level was significantly higher in HCC which had a higher methylation frequency than in NCs, CHB and LC (p < 0.05). Furthermore, the combination of the methylated CDH13 level and AFP level showed a better score: AUC = 0.796 (SE = 0.031, 95 %CI 0.735–0.857; p < 0.001) in male and AUC = 0.832 (SE = 0.057, 95 %CI 0.721–0.944; p < 0.001) in female compared to AFP alone for diagnosing HCC from NCs, CHB and LC. The methylation of CDH13 promoter was an independent predictor for assessing the prognosis of HCC patients (r=-1.378 p < 0.05). In conclusion, hypermethylation of CDH13 in PBMCs was associated with the underexpression of mRNA and the high risk of HCC. The methylation status of the CDH13 promoter in PBMCs was a potential noninvasive biomarker to predict the prognosis of HCC patients. 相似文献
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轮状病毒肠炎患儿免疫球蛋白和T细胞亚群的动态变化及其临床意义 总被引:5,自引:0,他引:5
目的研究轮状病毒肠炎(RVE)患儿血清中免疫球蛋白(Ig)和T细胞亚群的动态变化及其临床意义。方法采用透射比浊法和抗体致敏红细胞花环试验检测了38例生长发育正常的RVE患儿血清Ig和T细胞亚群。结果急性期血清IgG、IgA、IgM、CD3、CD4、CD4/CD8比值明显低于对照组及恢复期(P<0.01),尤其是IgA、CD4/CD8比值较对照组降低更为明显(P<0.001),CD8明显高于对照组及恢复期(P<0.01)。随着临床症状逐渐消失,恢复期IgG、IgA、IgM、CD3、CD4及CD4/CD8比值升高,CD降低并逐渐恢复正常,与对照组之间比较无显著性差异(P>0.05)。结论细胞免疫和体液免疫功能参与了RV的感染过程,IgA、CD4/CD8比值与疾病的预后有关 相似文献
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In wheat ctDNA,segments of ribosomal protein genes are dispersed repeats,probably conserved by nonreciprocal recombination 总被引:7,自引:0,他引:7
Summary Some dispersed repeated sequences and their flanking regions from wheat and maize ctDNAs have been characterized. Two sets of wheat ctDNA repeats were found to be the chloroplast ribosomal protein genesrpl2 andrpl23, plus nonfunctional segments of them, designatedrpl2 andrpl23. Pairwise comparisons were made between the wheatrp123 andrpl23, and the maizerp123 sequences. The precise patterns of homology suggest that the divergence of the wheat and maize nonfunctional (rpl23) sequences is being retarded by nonreciprocal recombination, biased by selection for individuals with functional (rpl23) sequences. The implied involvement of these sequences in mechanisms of homologous recombination, and therefore in the creation and spread of new ctDNA variants, is discussed. 相似文献
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EB病毒蛋白对免疫球蛋白产生的调节作用 总被引:2,自引:0,他引:2
目的检验EB病毒(Epstein-Barr Virus,EBV)蛋白对培养的人B细胞产生免疫球蛋白(Immunoglobulin,Ig)的影响.方法用UV灭活和热处理的EBV刺激培养的人脐带血B细胞,流式细胞仪检测UV灭活EBV组细胞CD5、CD3、CD4和CD8的表达,ELISA法检测培养上清中IgG和IgM,同时与EBV转化B细胞产生的IgG和IgM 作对比.结果第14天未检测到T细胞,CD5+B 细胞占43%;28天时CD5+B细胞占47%.UV灭活EBV组第10、18、22和26天IgG A值与对照组相比有显著差异(P<0.05),第10天以后各时间点IgM A值与对照组相比有显著差异(P<0.05).EBV转化培养B细胞40天,IgG和IgM A值与同期其它各组有显著差异(P<0.05).结论EBV蛋白有诱导Ig产生的作用. 相似文献
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Tabori U Mark Z Amariglio N Etzioni A Golan H Biloray B Toren A Rechavi G Dalal I 《Clinical genetics》2004,65(4):322-326
It has been recently shown that mutations in both of the recombination activating genes RAG1 and RAG2 are involved in each of the two different types of severe combined immunodeficiency (SCID) syndromes: T-B- SCID and Omenn's syndrome (OS). The objective of the study was to search for novel mutations in the RAG genes and to offer prenatal diagnosis for families that have been identified as at risk of T-B- SCID or OS. Mutation analyses of polymerase chain reaction products of RAG1/RAG2 genes were performed in 14 cases (T-B- SCID = 6 and OS = 8). Consanguinity was reported in seven (50%) families. Four missense mutations in the RAG2 gene in six of eight OS patients and in four of six T-B- SCID patients were detected. The C1845T transition leading to a Tre215Ile substitution is a novel mutation. All but one of the patients were homozygous for the detected mutations, possibly reflecting the consanguinity in these families and the relative rarity of the disease-causing mutations. In addition, three putative polymorphic sites were found. Prenatal diagnosis was offered to seven families, but three of them declined genetic counseling for religious reasons. In the remaining families, four pregnancies were successfully completed, and in one case, the family chose to have an abortion because of a homozygous mutation. Mutations in RAG1/RAG2 genes were detected in only some of the T-B- SCID or OS patients, and the molecular basis for the remaining cases has yet to be elucidated. Important factors such as religious beliefs need to be considered when offering prenatal diagnosis to certain families. 相似文献