Normal bovine adrenocortical cells and some human fibroblasts can be transformed by SV40T and H-Ras in a Ras-dependent manner. We recently reported that high levels of Ras derived from 5' LTR of retrovirrus can in...Normal bovine adrenocortical cells and some human fibroblasts can be transformed by SV40T and H-Ras in a Ras-dependent manner. We recently reported that high levels of Ras derived from 5' LTR of retrovirrus can induce highly malignant and fast growing tumors, while lower levels of Ras derived from internal ribosome entry site(IRES) promotes slower tumor growth and loss of malignancy. Ras derived from CMV promoters resulted in much lower Ras levels and loss of tumor malignancy and growth. Further studies showed that the tumors formed in the presence of lower levels of Ras and dominant negative P53(P53DD) had fewer apoptotic cells and grew faster than the tumors formed from cells with same level Ras and SV40T. Our studies suggest that low levels of Ras are insufficient to inhibit apoptosis induced by pRb inactivation. In contrast, high levels of Ras not only allow normal cells to exit senescence and form tumors, but also protect against pRb inhibition-induced cell apoptosis.展开更多
文摘目的探讨重组牛碱性成纤维细胞生长因子(recombinant bovine basic fibroblast growth factor,rb-bFGF)滴眼液对白内障术后干眼症患者泪液分泌、角膜损伤和氧化应激指标水平的影响。方法选取接受白内障手术并出现干眼症的患者120例作为研究对象,用随机数字表法分为观察组和对照组,每组60例。对照组用聚乙二醇滴眼液治疗,观察组在此基础上加用rb-bFGF滴眼液治疗。比较2组治疗前和治疗后泪液分泌量[SchirmerⅠ试验(SchirmerⅠtest,SIT)]、角膜损伤程度[角膜荧光素染色(fluorescein staining of the cornea,FL)评分]、泪膜破裂时间(tear film break up time,BUT)和氧化应激指标[超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malonaldehyde,MDA)和过氧化脂质(lipid peroxide,LPO)],并对临床疗效及安全性进行评价。结果观察组的总有效率高于对照组(P>0.05)。治疗后,2组SIT、FL评分、BUT和氧化应激指标均改善(P<0.05),且观察组改善效果更佳(P<0.05)。2组不良反应发生情况比较差异无统计学意义(P>0.05)。结论rb-bFGF滴眼液治疗白内障手术后干眼症疗效确切,可显著促进患者泪液分泌,减轻角膜损伤,延长泪膜破裂时间,改善氧化应激指标的水平。
文摘Normal bovine adrenocortical cells and some human fibroblasts can be transformed by SV40T and H-Ras in a Ras-dependent manner. We recently reported that high levels of Ras derived from 5' LTR of retrovirrus can induce highly malignant and fast growing tumors, while lower levels of Ras derived from internal ribosome entry site(IRES) promotes slower tumor growth and loss of malignancy. Ras derived from CMV promoters resulted in much lower Ras levels and loss of tumor malignancy and growth. Further studies showed that the tumors formed in the presence of lower levels of Ras and dominant negative P53(P53DD) had fewer apoptotic cells and grew faster than the tumors formed from cells with same level Ras and SV40T. Our studies suggest that low levels of Ras are insufficient to inhibit apoptosis induced by pRb inactivation. In contrast, high levels of Ras not only allow normal cells to exit senescence and form tumors, but also protect against pRb inhibition-induced cell apoptosis.
