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Expression of foreign genes transferred into mammalian cells by electroporation has been studied. The pX1TK gene, pSV2Neo gene and pUCEJ oncogene have been introduced into MLTK-cells and NIH/3T3 cells, respectively. Stable transformation transient expression of TK gene by MLTK-cells as well as stable and malignant transformation of NIH/3T3 cells have been obtained. Transient expression frequency is about 80% and stable transformation frequency is about 10~(-4). Integration of foreign genes into the cellular genome was verified with molecular hybridization. Tumor development was observed after inoculation of transformed celts into nude mice. 相似文献
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A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2. 相似文献
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单分散磁性P(St/BA/MAA)微球的制备 总被引:10,自引:0,他引:10
在共沉淀法合成超细磁流体的基础上 ,以苯乙烯 (St)、丙烯酸丁酯 (BA)和甲基丙烯酸 (MAA)为共聚单体 ,在不同的介质体系中采用无皂乳液聚合法制备了单分散 ,粒径范围为 80~ 2 30nm的磁性P(St BA MAA)微球 .详细探讨了介质极性、磁流体中表面活性剂含量对磁性高分子微球粒径和单分散性的影响 .实验结果表明 ,在一定范围内随介质极性降低 ,磁性高分子微球的单分散性提高 ,随表面活性剂用量增加 ,单分散性变差 .总体来看 ,磁性高分子微球的单分散性与其表面静电斥力密切相关 ,过大或过小的静电斥力均会导致磁性高分子微球单分散性的降低 . 相似文献
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吴旻 《理化检验(化学分册)》2020,56(7):777-781
正在实验室常使用标准物质或质量控制物质、测量设备的期间核查、实验室内比对等方式对试验过程进行监控。同时,在AC7101/1G:2019《NADCAP对所有材料实验室的总体要求》的附录中要求各申请专业每年度需按照一定频次完成能力验证和内部比对试验,对于一些专业还专门提出了对人员的内部比对和对设备的内部比对的频次要求。为适应中国合格评定国家认可委员会(CNAS)的"确保结果有效性"的要求、国家航空航天和国防 相似文献
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G-banded chromosomes of primary cultures taken from mucosal epithelium adjacent to esophagealcancer (EC) were first analyzed. Consistent chromosomal changes, i. c. marker chromosomes, appeared in2 of seven specimens of esophageal epithelium. Some of the marker chromosomes are very similar to thosefound in EC8501 cell line. These results imply that the cytogenetic analyses of the mucosal epitheliumadjacent to EC may detect the numerical and structural chromosome aberrations occurring at the very be-ginning of carcinogenesis of esophageal epithelium. 相似文献
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With the use of the EB virus-producing lymphoblastoid cell line H_(18), an attempt wasmade to infect the monolayer cell culture of nasopharyngeal tissue from the normal tupaia,and an EB virus-producing, human-tupaia hybrid cell line was established. The mechanism of entry of EB virus into cells other than B lymphocytes is discussedin this paper. 相似文献
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一种存在于林县霉变玉米面中的新亚硝胺化合物——N-3-甲基丁基-N-1-甲基丙酮基亚硝胺(MAMBNA)已人工合成。利用新生金仓鼠肺成纤维细胞体外恶性转化模型,引入微粒体酶代谢激活系统检测了MAMBNA。实验结果,MAMBNA同已知的强化学致癌物N-甲基-N'-硝基-N-亚硝基胍和二乙基亚硝胺一样,能使体外培养的金仓鼠肺成纤维细胞发生恶性转化。证明MAMBNA是林县这一高癌地区的一种环境致癌物。本系统除可用于检测可疑环境致癌物外,尚可作为研究癌变机理的体外模型。 相似文献
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反义人myc基因的表达对食管癌细胞恶性生长的抑制 总被引:1,自引:0,他引:1
本文构建了一个含有反义人c-myc基因片段(第三外显子及3’旁侧序列)的逆转录病毒载体——pDAM3.用磷酸钙沉淀法将pDAM3导入病毒包装细胞PA317,经过筛选获得病毒效价8×10~5CFU/ml的单克隆病毒包装细胞,DNA杂交分析证实病毒载体序列稳定地整合到PA317细胞中.利用DAM3病毒成功地感染了人食管癌细胞系EC8712,得到G418抗性细胞EC-DAM3,RNA杂交结果表明EC-DAM3细胞中存在着大量的反义mycRNA分子.EC-DAM3细胞的生长速率较之EC8712细胞下降50%,[~3H]胸腺嘧啶核苷掺入降低45%,细胞在裸鼠体内形成肿瘤的能力受到明显抑制. 相似文献