Survivin启动子介导的胞嘧啶脱氨酶(CD)自杀基因的抗肿瘤研究

目的 探讨Survivin启动子介导的CD/5-FC自杀系统的抗肿瘤效果.方法 利用Survivin启动子替换pEGFP-N1载体上的巨细胞病毒(CMV)启动子,构建重组表达载体pSurP-EGFP,通过报告基因绿色荧光蛋白(GFP)的表达确定Survivin启动子的特异性;将酿酒酵母的胞嘧啶脱氨酶(CD)基因克隆在pSurP-EGFP中,构建成重组载体pSurP-CD,转染肿瘤细胞后利用毛细管电泳仪检测前药5-氟胞嘧啶(5-FC)的转化效率,同时分析肿瘤细胞的凋亡.结果 GFP的表达表明Survivin启动子具有较好的肿瘤靶向性;毛细管电泳检测表明CD能够有效地将5-FC转化为5-FU,显微镜观察和流式分析表明了Survivin启动子介导的CD的抗肿瘤效果.结论 Survivin启动子能有效地介导CD自杀基因的表达,具有较好的靶向性抗肿瘤效果.     

血管内皮生长因子受体启动子驱动双自杀基因联合survivin反义寡核苷酸对结直肠癌细胞及血管内皮细胞的特异性杀伤作用

目的探讨腺病毒介导血管内皮生长因子受体（KDR）启动子驱动的CDglyTK融合基因（AdKDR-CDsbrTK）体系联合survivin反义寡核苷酸（ASODN）对结直肠癌细胞（sw620）及血管内皮细胞（ECV304）的特异性杀伤作用。方法将质粒pAdEasy—KDR-CDglyTK在293细胞内包装、扩增产生重组腺病毒。体外感染表达KDR的SW620、ECV304细胞株,同时用survivin ASODN转染同一细胞株,观察腺病毒的感染效率和ASODN的转染情况。应用RT．PCR和Western印迹检测CDglyTK和survivin基因的表达．MTT法测定两者联合应用对细胞株的杀伤效应和旁观者效应。结果survivin ASODN可转染重组腺病毒感染的细胞,并且两者的转染及感染效率无明显变化。CDglyTK可在SW620、ECV304细胞株高效表达。survivin ASODN可明显降低survivin蛋白表达。各基因治疗组细胞存活率明显低于阴性对照组（P〈0．001）。survivinASODN与AdKDR—CDglyTK基因联用后。随着前药浓度的增加,细胞存活率迅速下降,两者联合作用与单一基因作用相比,差异具有统计学意义（P〈0．05）。但在GCV100μg／ml、5-FC 2000μg／ml时,联合基因治疗组细胞存活率略低于单用AdKDR-CDglyTK,两者间差异无统计学意义（P〉0．05）。Survivin ASODN和AdKDR—CDglyTK联合作用,在前药浓度较低时表现为协同效应,并具有更明显的旁观者效应。结论KDR启动子调控的AdKDR-cDglyTK体系和survivin ASODN基因联合,较单一基因具有更强的特异性杀伤结直肠癌细胞及血管内皮细胞的作用。     

Suicidal thinking in multiple sclerosis

Purpose.?Studies demonstrate that suicidal ideation ((SI)) is greater in persons with multiple sclerosis ((MS)) than in the general population. SI may offer some MS patients a mechanism for feeling in control of their lives, in the face of a daunting, unpredictable disease. In this study, we determined what specific mental constructs or perceptual themes occur for MS patients experiencing SI, while also examining the construct of ‘control’ as a central theme.

Methods.?Individual interviews ((N == 16)) were audiotaped, transcribed and qualitatively analysed by two independent raters to test for key themes in MS patients reporting SI.

Results. In relation to SI, eight key themes were identified by both raters as having been expressed in interviews: perceived loss of control, increased family tension, loneliness, hopelessness and frustration, physical and psychological impact of MS, loss of perceived masculinity or femininity, regaining control and failure to achieve desired or expected role functioning. We created a model to explain the emergence of these themes as they contribute to SI among patients with MS. All participants indicated that perceived loss of control elicited thoughts of suicide.

Conclusion.?Perceived loss of control appears to be a major disease related burden associated with SI in MS patients.     

Adenoviral gene therapy of gastrointestinal tumour metastases in the liver

Summary

Gastrointestinal cancers are the second most common cause of cancer death. Once metastasised, 5 year survival is < 5% in gastrointestinal cancer. Because the liver is the preferred site for distant organ metastasis of colon cancer, treatment of hepatic metastases remains a challenge for experimental cancer therapy approaches. Gene therapy provides tools to combat cancer on a molecular level. In contrast to conventional chemotherapy, vectors are used to insert DNA into tumour cells, neighbouring parenchymal cells, or cells involved in the cellular immune defense. The shuttle vectors are of nonviral or viral origin. Adenoviral vectors have been developed for high efficiency in vivo gene transfer and expression. The incorporation of foreign DNA can result in direct tumour cell killing, using suicide genes. Cytokine genes, or genes encoding for tumour-specific antigens recognised by the cellular host immune system, can result in anti-tumoral immune stimulation. Experimental suicide-gene expression in hepatic metastasis of gastrointestinal tumours, utilising thymidine kinase and cytosine deaminase, results in significant tumour necrosis and regression. Intratumoral interleukin-2 and interleukin-12 gene expression can induce a systemic cellular antitumoral immune response, with long-term survival demonstrating the potential of this new therapeutic approach in cancer therapy.     

High prevalence of suicide risk in people living with HIV: who is at higher risk?

A cross-sectional study was developed to evaluate suicide risk and associated factors in HIV/AIDS patients at a regional reference center for the treatment of HIV/AIDS in southern Brazil. We assessed 211 patients in regard to suicide risk, clinical and sociodemographic characteristics, drug use, depression, and anxiety. Suicide risk was assessed with Mini International Neuropsychiatric Interview, Module C. Multivariate analysis was performed using Poisson regression. Of the total sample, 34.1% were at risk of suicide. In the multivariate analysis, the following variables were independently associated with suicide risk: female gender; age up to 47 years; unemployment; indicative of anxiety; indicative of depression; and abuse or addiction on psychoactive substances. Suicide risk is high in this population. Psychosocial factors should be included in the physical and clinical evaluation, given their strong association with suicide risk.