Effect of Amine Type on the Expression of Plasmid DNA by Cationized Dextran

The objective of this study is to prepare a non-viral carrier of gene expression from the polysaccharide dextran and evaluate the effect of amine compounds introduced to dextran on the level of gene expression. Dextran with a molecular weight of 74 × 10³ was cationized by the chemical introduction of different amine compounds. The cationized dextran was complexed with a plasmid DNA and the vitro gene transfection was investigated for HeLa cells. The level of gene expression depended on the amine compound introduced to dextran. The highest level was observed for the complex of spermine-introduced dextran and plasmid DNA. The highest cellular internalization and the best buffering effect were observed among every cationized dextran. Every complex did not show any cytotoxicity. It is concluded that the superior properties of spermine-introduced dextran enabled the plasmid DNA to enhance the expression level to a great extent compared with other cationized dextrans. Cationized dextran is a promising non-viral carrier of plasmid DNA.     

肝硬变门静脉高压症患者肝细胞凋亡与原癌基因表达的研究

目的探讨肝细胞凋亡与肝硬变及原癌基因的关系。方法取正常人及肝硬变门静脉高压症患者的肝组织。行透射电镜检查，并检测其凋亡细胞及原癌基因表达。结果肝硬变患者肝组织内的凋亡细胞及凋亡指数高于正常人；肝组织原癌基因c-myc，c-fos和bcl-2均呈过度表达，而正常人肝组织则无表达。结论肝细胞凋亡在肝硬变的演变过程中发挥一定作用，原癌基因c-myc，c-fos和bcl-2参与肝细胞凋亡的调控。     

结直肠癌中MEK2/ERK信号传导通路的研究

目的　研究丝裂原激活化蛋白激酶 (MAPK )中MEK2 /ERK信号传导通路在结直肠癌发生发展中的作用。方法　 ( 1)采用Westernblot检测 5 2例结直肠癌组织及其邻近肠黏膜中MEK 2蛋白的表达。 ( 2 )用丝裂原细胞外激酶 (MEK )抑制剂作用于结肠癌细胞系SW 480 ,然后以MTT法检测细胞增殖状态 ;用Westernblot检测MEK2 ,p ERK及其靶基因产物C myc的表达。结果　结直肠癌组织中MEK2蛋白表达水平明显高于邻近的肠黏膜 (P <0 .0 5 ) ,且与肿瘤的分化、Dukes分期及淋巴结转移有关 (P <0 .0 5 )。应用MEK的抑制剂后SW 480细胞中MEK2 ,p ERK ,C myc表达水平随作用时间延长而下降。结论　MEK2活性增高与结直肠癌细胞侵袭力有关 ,阻断MEK2 /ERK信号传导通路可以抑制结肠癌细胞的增殖 ,促进其凋亡。