OBJECTIVE To investigate the effect of polyethylene imine glycol （PEI-PEG）/siRNA nanocomposites in the in vitro transfection of human gastric cancer SGC7901 cell lines and the down-regulation of gene expression of the adherence factor CD44v6. METHODS PEI-PEG/siRNA nanoparticles, in different N/P ratios, were synthesized and transfected into gastric cancer cells. Lipo2000/siRNA was used in the control group. The transfection efficiencies were observed under fluorescence microscope. The cytotoxicity of the nanoparticles was measured using the MTT assay （mononuclear cell direct cytotoxicity assay）, and the down-regulation effect of siRNA on CD44v6 gene was evaluated by Western blot. Based on the different N/P ratios, PEI-PEG/siRNA composites were synthesized and transfected into gastric cancer cells. Lipo2000/siRNA was used in the controls. The transfection efficiency was observed under fluorescence microscope. The cytotoxicity of the nanoparticles was measured using the MTT assay and the down-regulation effect of siRNA on CD44v6 gene was evaluated by Western blot. RESULTS After transfection, the transfection efficiency of the PEI-PEG/siRNA nanocomposites increased incrementally in N/P ratio value. The transfection efficiency improved with an increase in N/P ratio. When the N/P value was 15, fluorescence became more intense in the PEI-PEG/siRNA group than in the Lipo2000/siRNA group. At the same time, cell viability was （80.4 ± 5.6）% in the MTT reduction assay, which was similar to that in the Lipo2000/siRNA group. The results of Western blot analysis showed that the expression level of CD44v6 protein decreased to （59.7 ± 3.0）% after siRNA-CD44v6 was inhibited. CONCLUSION PEI-PEG could effectively form the nanocomposite in combination with siRNA, be transfected into the SGC7901 gastric cancer cell lines and inhibit CD44v6 protein expression. Moreover, as a genetic carrier, PEI-PEG copolymer has greater advantages, including high transfection e. ciency, less cytotoxicity and an easily alterable vect
目的构建库容量大、多样性好的核糖体展示单链抗体库,为进一步筛选单链抗体奠定基础。方法对2006年10月1日至11月31日收集于中山大学附属第二医院的人外周血(健康成人2名,胃癌3例,肠癌3例,胰腺癌1例,每例各5mL,新生儿2名各2mL)分离淋巴细胞,提取RNA;利用RT-PCR克隆出全套重链可变区基因(variable region of heavy chain,VH)、轻链可变区基因(variable region of light chain,VL);然后利用重叠延伸PCR技术连接构建VH-VL单链抗体库。并通过连接T-Vector转化E.coli JM109大肠埃希菌,经蓝白筛选,挑取阳性克隆测序以鉴定单链抗体组装。结果试验成功构建了单链抗体核糖体展示模板,其库容达1.1×1013。结论大容量核糖体展示单链抗体库的构建为筛选多种人源性单链抗体奠定了基础。
目的探讨广东地区急性胰腺炎(AP)的临床特点和发病规律。方法总结分析中山大学附属第二医院及广东省人民医院1986-2005年 AP 住院患者共1316例临床资料,并对结果进行统计分析。结果 1986-1990年间病例数占同期内、外科住院总人数的0.19%,1991-1995年间上升为0.36%,1996-2000年间升至0.54%,而2001-2005年间则高达为0.71%。1316例患者中胆源性胰腺炎占60.48%,其余依次为高脂血症胰腺炎、特发性胰腺炎。临床症状以上腹部疼痛为主,伴或不伴腰背部放射痛,多数伴有恶心、呕吐等消化道症状。动态增强 CT 扫描是明确诊断、严重度分级及发现并发症的准确影像学方法。非手术治疗1104例,死亡24例;手术治疗212例,死亡48例。结论 AP 发病例数逐年增多,AP 发病因素多而复杂,胆道疾病仍为主要病因。影像学检查有助于早期诊断及严重度分级,早期治疗可采用中西医结合的非手术疗法,严格掌握手术指征,合理使用内镜技术,均能取得理想的治疗效果。
