背景与目的：有研究表明，尿中修饰核苷的含量在多数恶性肿瘤患者中有明显升高。本研究拟探讨检测尿中核苷在胃癌诊断中的意义。方法：应用高效液相色谱法分别检测50名正常人与48例胃癌患者尿中15种核苷的水平，48例胃癌患者中有25例同时接受了血清CEA检测。结果：50名正常人和48例胃癌患者尿中15种核苷的平均值分别依次为：Pseu 22.91±4.90，34.87±21.41；00.34±0.32，0.62±0.82；AO.58±0.16，0.96+0.75；C0.17±0.15，0.24±0.19：m 500.03±0.07，0.07±0.06：10.26±0.10，0.43±0.36；mlll.34±0.34，2.44±1.39；ac4CO.75±0.24，1.08±0.72；GO.09±0.04，0.14±0.10；X1.20±0.42，1.90±1.09：m2G0。61±0.16，1.00±0。69；m6A0。04±1.13，0.07±0.08：mIA2.26±0.56，3.71±2.21：m22C1.34±0.27，2.25±1.39；mIG0。80±0。25，1。41±0.86。癌患者尿中除m5U外，其余14种核苷的平均值明显高于正常人（P<0.05）；次黄嘌呤与肿瘤大小，淋巴结转移正相关（P<0.05）；黄嘌呤核苷与肿瘤淋巴结转移正相关（JD<0.05）。以其中15种核苷浓度作为数据矢量，结合主成分分析。投影判别法区分正常人和胃癌患者，63%的胃癌患者被识别。识别率大大高于CEA检测（12%）。结论：胃癌患者尿中修饰核苷水平升高，检测尿中修饰核苷对胃癌的初筛有。定的参考意义。

Accurate and fast genotyping of single nucleotide polymorphisms(SNPs)is important in the human genome project. Here an automated fluorescent method that can rapidly and accurately genotype multiplex known SNPs was developed by using a homemade kit, which has lower cost but higher resolution than commercial kit. With this method, oncogene K-ras was investigated, four known SNPs of K-ras gene exon 1 in 31 coloerctal cancer patients were detected. Results indicate that mutations were present in 8(26%)of 31 patients, and most mutations were localized in codon 12. The presence of these mutations is thought to be a critical step and plays an important role in human colorectal carcinogenesisas

对单核苷酸多态性（SNP）的概念及特性作了简要说明，介绍了14种检测SNP的方法，讨论了各种方法的原理及优缺点，并对目前SNP在遗传图的绘制、遗传病致病基因的搜寻、药物设计及法医学等方面的应用及其研究进展进行了综述。引用文献29篇。

对人类基因组中的单核苷酸多态性进行快速而准确的定位和分型是人类基因组计划的重要内容。本文利用SNaPshot试剂盒，建立了一种以多重引物延伸为基础、可同时对多个已知单核苷酸多态性位点进行快速而准确的遗传分型的方法。利用这一方法检测了20例大肠癌病人肿瘤组织中错配修复基因hMLH1和抑癌基因P53的8个单核苷酸多态性位点（包括5个突变热点），其中一例发现错配修复基因hMLH1的384位密码子处发生GTT→GAT的杂合性突变。对该基因外显子的直接测序结果与SNaPshot检测结果完全吻合，充分证明了该方法的可靠性。

Fluorescent-based single-strand conformation polymorphism(F-SSCP)analysis with capillary electrophoresis(CE)is the most common method for the detection of mutation because of its high sensitivity and resolution.In this study,we prepared an inexpensive linear polyacrylamide(LPA),and successfully applied it to CE-SSCP analysis and tandem CESSCP/heteroduplex analysis(HA)of the P53 gene on an ABI capillary genetic analyzer.A comparison of the sieving capabilities of a homemade LPA and commercial polydimethylacrylamide(PDMA)demonstrates that the homemade LPA has a higher resolution,a shorter analysis time,and is more suitable for tandem SSCP/HA than commercial PDMA.To show the usefulness,mutations of P53 gene exon 7-8 in 37 tumor samples were investigated by using homemade LPA.The results indicate that 10 mutations were found in 9 of 37 cases; the majority of P53 mutations were missense mutations,and 70% were located in exon 7,which plays an important role in neoplastic progression in human tumorigenesis.