To enhance the specific cytotoxic effects caused by the transfer of the E. coli cytosine deamlnase (cd) and lISVl-tk to CEA (carcinoembryonic antigen)-produeing cells, the expression of the ed-tk fusion gene, driven by the CEA promoter, was investigated followed by treatment with 5-FC and GCV in combination with radiation. The expression vector pCEAcd-tk, based on pcDNA3, was introduced into CEA-produeing cells using liposomes. In CEA-producing cells, the CEA promoter could efficiently drive the expression of the fusion suicide gene. The expression activity of the E. colcoli ed gene driven by the CEA promoter was about tbree times higher than that driven by the CMVCMV promoter in transfeeted LoVo cells. A combination of 5-FC and GCV could cause higher cytotoxicity to the cells expressing CD and TK than the use of a single prodrug alone. The cytotoxic effect after combining the two prodrugs with radiation was the highest among all treatments in vitro. In vivo, the result of a subrenal capsule assay showed that tile inhibition rates for 5-FC (0.5mg/g) and GCV (0.1rag/g) to GLC-82 cells transfected witb pCEAcd-tk were 18.04% and 55.00%, respectively. A combination of the prodrugs at the same dose resulted in a 152.50% inhibition rate. In addition, the bystander effect exerted by the pCEAcd-tk/5-FC+GCV system in vilro was greater than that induced by cd/5-FC or tk/GCV alone.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a cotton X-linked hereditary enzymopathy. We describe here the techniques based on matrix-assisted later desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and multiprimer extension (multi-PEX) to detect the most commnon Chinese G6PD mutations, which are the single-point mutations G-T at nt 1376, G-A at nt 1388, A-G at nt 95 G-T at nt 392. C-T at nt 1024, and C-T al nt 1311 Fifteen samples were genotyped using this method coupled with direct sequencing, after identification of G6PD mutations by ARMS. In this study, we identified a mutation G-Tat nt 1376, which had been G-A at nt 1388 using ARMS, while the result of seqnencthg corresponds with ours This indicates the reliability of this method. Furthermore. since it can scan six common Chinese G6PD mutations simultaneously in one mass spectrum, this approach could be used to fast diagnose these G6PD mutafions accurately in large-scale analysis.

目的基于变性高效液相色谱技术，建立一种不需测序和杂交的新的mtDNA控制区多态性分析系统。方法mtDNA控制区序列(包括HVI，HVⅡ和HVⅢ)被分为4个扩增片段，采用配对分析突变检测模式进行DHPLC分析。对DHPLC检测条件（包括柱温和洗脱梯度等）进行优化。对100个不同类型差异序列的组合配对以检验该方法的检测效力。结果10组序列相同的样本配对DHPLC图谱均只显示1个样品峰。对序列相差1个碱基～7个碱基、插入（/缺失）1个碱基、插入（/缺失）2个碱基等类型的90个扩增片段组合，用DHPLC进行分析，均得到≥2个样本峰的DHPLC图谱。序列差异检出率达100%。该技术可检测的异质性DNA成分的最小百分含量为10%。结论DHPLC-mtDNA控制区多态性分析系统快速、经济和实用。在检测mtDNA异质性方面较直接测序更灵敏。

为了探讨具有不同放射敏感性的CNE1、CNE2鼻咽癌细胞株中ATM/P13K区基因突变的情况，采用反转录聚合酶链式反应(RT--PCR)技术和PCR产物直接测序方法(荧光标记的ddNTPs循环测序)，对CNE1、CNE2中ATM的P13K关键区域进行突变检测。结果表明，所测CNEl、CNE2中的ATM/P13K区序列中没有发生突变，认为鼻咽癌细胞株CNE1、CNE2间内在的放射敏感性的差异可能与ATM/P13K区基因突变不相关。

背景与目的：ATM(Ataxia-telangiectasiamutant)蛋白与细胞放射敏感性密切相关。本研究探讨ATM蛋白在具有不同放射敏感性的鼻咽癌细胞系CNE1，CNE-中的表达。方法：采用免疫荧光标记技术，对CNEI、CNE2中的ATM蛋白进行激光扫描共聚焦显微镜(LSCM)分析。结果：ATM蛋白定位于细胞核及胞浆中，并以细胞核为主，且CNEI细胞核中ATM蛋白阳性细胞的荧光强度较CNE2强；半定量分析，CNE1中ATM蛋白表达的积分吸光度值为9×10，CNE2中为3×10。结论：ATM蛋白的表达在CNE1、CNE2中有差别，这种差别可能与它们所具有的不同放射敏感性有关。