大鼠GDNF基因的克隆表达及对PC12工程细胞的影响

克隆与表达大鼠胶质细胞源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)并观察其对PC12工程细胞的影响。从新生4天的SD大鼠海马组织中提取总RNA，通过RT-PCR方法，扩增出GDNFcDNA。构建表达质粒pET-GDNF，转化大肠杆菌BL21(DE3)，IPTG诱导GDNF表达并在Ni^2 -NTA柱上用一步复性法纯化和复性。把PCDNA3．0-GFRαl和pcDNA3．0-BET质粒双转染入PC12细胞，C-418筛选稳定克隆，构建PC12工程细胞。用GDNF刺激工程细胞，3天后观察其存活和分化。大鼠GDNFcDNA的克隆与表达获得成功，纯化和复性的重组GDNF蛋白可显著增强PC12-GFRαl—RET工程细胞的存活和分化。初步明确GDNF诱导PC12工程细胞存活和分化是通过RET-依赖途径。     

人端粒酶反转录酶基因转染人胚胎大脑皮质神经元的凋亡

背景：人端粒酶反转录酶重组腺病毒转染原代培养的人胚胎大脑皮质神经元,可以促进细胞生存,抑制凋亡。目的：观察人端粒酶反转录酶对β淀粉样蛋白(amyloid β-protein,Aβ)诱导人胚胎大脑皮质神经元凋亡的影响。方法：人胚胎大脑皮质神经元原代培养后,分为3组：对照组、Aβ_25-35组和人端粒酶反转录酶组。Aβ_25-35组和人端粒酶反转录酶组细胞在培养144 h后,用Aβ_25-35 5 μmol/L干预24 h。人端粒酶反转录酶组在Aβ_25-35      5 μmol/L干预72 h进行人端粒酶反转录酶基因转染。结果与结论：原代培养的人胚胎大脑皮质神经元培养7 d后,出现凋亡细胞,而Aβ_25-35干预后使凋亡细胞数量增加,而人端粒酶反转录酶可防止Aβ_25-35诱导的人胚胎大脑皮质神经元的凋亡。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

NDRG2基因反转录病毒载体的构建及表达

背景：NDRG2(N-Myc Downstream Regulated Gene 2)是一个新的抑癌基因,既可以增强经典抑癌通路的抗肿瘤效应,又可以对正常细胞的癌变起到监控。有关NDRG2在骨髓瘤发生中的功能和作用至今还未见报道。 目的：构建NDRG2基因反转录病毒表达载体,利用包装的病毒感染人骨髓瘤细胞系U266,检测NDRG2的表达情况。 方法：设计与合成引物,提取U266细胞的RNA,反转录和PCR扩增,经BamHⅠ和TaqⅠ双酶切,琼脂糖凝胶电泳,切胶回收进行连接转化,并再次酶切鉴定;并将构建的载体包装为反转录病毒,感染U266细胞,筛选出稳定表达NDRG2的U266细胞(U266-NDRG2)克隆扩大培养,利用Western blot实验检测筛选到的U266细胞中NDRG2的表达。 结果与结论：成功构建了携带NDRG2基因表达的重组载体pBaba-puro-NDRG2,并包装为反转录病毒,筛选到的U266细胞(U266-NDRG2)中NDRG2蛋白表达明显高于U266-cherry细胞和U266细胞。结果可见利用反转录病毒载体基因重组技术成功构建出携带相应基因的反转录病毒,为研究NDRG2在人骨髓瘤中的作用奠定了实验基础。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

CHD患者血浆ET-1、GMP-140和血清cTnI检测的临床意义

目的：探讨冠心病（CHD）患者血浆ET-1、GMP-140和血清心肌肌钙蛋白Ⅰ（cTnI）水平的变化及意义。方法：应用放射免疫分析和酶免法对96例CHD患者进行了血浆ET-1、GMP-140和血清cTnI水平的测定,其中稳定型心绞痛（SAP）36例,不稳定型心绞痛（UAP）41例,急性心肌梗死（AMI）19例。并与35例正常健康人作比较。结果：CHD患者血浆ET-1、GMP-140和血清cTnI水平均非常显著的高于正常人组（P〈0.01）,急性AMI组和UAP组又高于SAP组（P〈0.05）,且血清cTnI水平与血浆ET-1、GMP-140水平呈正相关。结论：检测CHD患者血浆ET-1、GMP-140和血清cTnI水平的变化对CHD的发生和发展以及疗效和预后观察均具有重要的临床意义。     

瘤源性IDO2对黑色素瘤形成及生长的影响

目的研究B16-BL6细胞内IDO2基因表达对小鼠黑色素瘤生长、发展及抗肿瘤免疫的影响。方法通过G418药物筛选建立稳定细胞系B16-BL6/IDO2^+及B16-BL6/IDO2^+,q PCR法检测IDO2的表达,MTT实验检测IDO2表达对细胞增殖的影响;然后以构建的稳定细胞在小鼠体内建立肿瘤模型,观察IDO2表达对黑色素瘤形成、生长的影响;最后在处死小鼠后通过流式细胞术检测引流淋巴结内Treg、CD4^+/CD8^+T细胞百分比及T淋巴细胞凋亡率,LDH法检测肿瘤特异性细胞毒反应来观察肿瘤组织内IDO2表达对引流淋巴结内肿瘤免疫的影响。结果成功建立B16-BL6/IDO2^+及B16-BL6/IDO2^-稳定细胞系:B16-BL6/IDO2^-细胞持续稳定低表达IDO2且不受LPS及IFN-γ的诱导;与B16-BL6/IDO2^+细胞相比,B16-BL6/IDO2^-细胞在体外增殖速度减慢,体内实验显示其肿瘤生长速度减慢、肿瘤质量减轻;进一步流式细胞术结果发现:引流淋巴结内Treg百分比下降、CD8^+T细胞数量增加、T淋巴细胞的凋亡率减少;LDH法检测CD8^+细胞特异性特异性杀伤肿瘤细胞反应增强。结论黑色素瘤细胞内IDO2的表达参与体内肿瘤的生长过程,且能影响其引流淋巴结内肿瘤免疫反应。     

流式细胞仪分选非染色S期CHO细胞有助于提高聚乙烯亚胺的转染效率

目的利用流式细胞仪(flow cytometry,FCM)分选获得非染色、同步化的中国仓鼠卵巢(Chinese hamsterovary,CHO)细胞,观察聚乙烯亚胺(polyethylenimine,PEI)在不同周期CHO细胞的瞬时转染和稳定转染效率。方法悬浮培养CHODG44细胞,应用流式细胞仪的光学参数-前向角和侧向角,在细胞主群中设置12个门,然后进行分选。分选出的各门内细胞经碘化丙啶(PI)染色进行细胞周期检测。以PEI为载体分别向含G0/G1、S、G2/M比例较高的细胞亚群和未经分选的细胞转染含绿荧光蛋白(Green Fluorescence Protein,GFP)质粒,利用流式细胞仪检测瞬时转染、稳定转染效率。结果细胞DNA含量与侧向角相关,各细胞亚群G0/G1期细胞所占比例总体上随着侧向角的增大而减小,G2/M细胞所占比例随着侧向角的增大而增多。低侧向角的细胞亚群P2内G0/G1期细胞比例可达80.49%,中侧向角的细胞亚群P7内S期细胞比例可达61.14%,高侧向角的细胞亚群P13内G2/M期细胞比例可达49.88%。转染48h,GFP阳性细胞在G2/M期细胞比例较高的细胞亚群所占比例最高,但瞬时转染效率,S期细胞比例较高的细胞群大于G2/M期细胞比例较高的细胞群。转染2w,稳定转染效率仍为S期细胞比例较高的细胞亚群大于其它细胞亚群及未分选的混合细胞群。结论应用流式细胞仪的光学参数可以有效分选非诱导、无染色分别含有较高比例各周期时相的CHO细胞;PEI的转染效率与转染时细胞所处的细胞周期时相相关,且S期细胞亚群的瞬时和稳定转染效率均高于其它细胞周期亚群。     

表达H9N2禽流感病毒HA1蛋白的转基因和缓艾美耳球虫的构建

H9N2亚型禽流感病毒已经被证实可以传播到人类,对它存在的潜在危害已受到越来越多的关注。因此,研究安全而有效的H9N2禽流感病毒疫苗已迫在眉睫。为研究和缓艾美耳球虫作为活载体表达及运输禽流感病毒抗原的潜能,本研究构建了可稳定表达H9N2禽流感病毒HA1蛋白的转基因和缓艾美耳球虫。利用黄色荧光蛋白（YFP）及融合的乙胺嘧啶抗性基因（DHFR-TSm2m3）作为报告基因及筛选基因,我们将表达H9N2禽流感病毒HA1抗原的质粒载体核转球虫子孢子,接种鸡后在乙胺嘧啶药物的选择压力下进行筛选并连续传代获得转基因和缓艾美耳球虫系。利用染色体步移和免疫印迹证实了HA1基因的成功插入和表达;利用间接免疫荧光证实HA1蛋白定位于球虫子孢子细胞膜表面和头部。研究进一步发现,转基因球虫的繁殖力与野生球虫相当,感染后亦于第6d达到排卵囊高峰。该转基因和缓艾美耳球虫株具有作为疫苗活载体的潜能。     

Periostin过表达对鼻咽癌6-10B细胞侵袭和迁移的影响及机制

目的探讨外源表达periostin蛋白对鼻咽癌(NPC)6-10B细胞侵袭和迁移能力的影响及机制。方法采用脂质体转染技术建立稳定高表达periostin的6-10B细胞,RT-PCR结合Western blotting检测转染效率,Tanswell分析periostin高表达后6-10B细胞侵袭和迁移能力的改变,明胶酶谱法检测基质金属蛋白酶(MMPs)活性的变化;免疫组织化学检测整合素(integrin)αvβ5在转染periostin前后6-10B细胞中的表达以及其与periostin在鼻咽癌和正常鼻咽黏膜组织中的表达,image-pro Plus 6.0软件进行图像分析及吸光度测定,统计学分析鼻咽癌组织中periostin和integrinαvβ5表达强度的相关性。结果 Periostin过表达的6-10B细胞侵袭、迁移能力明显增强,细胞培养上清中MMP-2、MMP-9活性增加,integrinαvβ5在periostin过表达的6-10B细胞及NPC组织的表达明显强于对照组,Spearman相关性分析显示,integrinαvβ5和periostin在NPC组织中的表达强度成正相关(r=0.682,P=0.000)。结论外源表达periostin能促进NPC的侵袭和转移,其机制可能是通过与NPC细胞膜上integrinαvβ5受体结合而提高MMPs的活性。     

A Web-Based Program Improves Physical Activity Outcomes in a Primary Care Angina Population: Randomized Controlled Trial

Background

Angina affects more than 50 million people worldwide. Secondary prevention interventions such as cardiac rehabilitation are not widely available for this population. An Internet-based version could offer a feasible alternative.

Objective

Our aim was to examine the effectiveness of a Web-based cardiac rehabilitation program for those with angina.

Methods

We conducted a randomized controlled trial, recruiting those diagnosed with angina from general practitioners (GPs) in primary care to an intervention or control group. Intervention group participants were offered a 6-week Web-based rehabilitation program (“ActivateYourHeart”). The program was introduced during a face-to-face appointment and then delivered via the Internet (no further face-to-face contact). The program contained information about the secondary prevention of coronary heart disease (CHD) and set each user goals around physical activity, diet, managing emotions, and smoking. Performance against goals was reviewed throughout the program and goals were then reset/modified. Participants completed an online exercise diary and communicated with rehabilitation specialists through an email link/synchronized chat room. Participants in the control group continued with GP treatment as usual, which consisted of being placed on a CHD register and attending an annual review. Outcomes were measured at 6-week and 6-month follow-ups during face-to-face assessments. The primary outcome measure was change in daily steps at 6 weeks, measured using an accelerometer. Secondary outcome measures were energy expenditure (EE), duration of sedentary activity (DSA), duration of moderate activity (DMA), weight, diastolic/systolic blood pressure, and body fat percentage. Self-assessed questionnaire outcomes included fat/fiber intake, anxiety/depression, self-efficacy, and quality of life (QOL).

Results

A total of 94 participants were recruited and randomized to the intervention (n=48) or the usual care (n=46) group; 84 and 73 participants completed the 6-week and 6-month follow-ups, respectively. The mean number of log-ins to the program was 18.68 (SD 13.13, range 1-51), an average of 3 log-ins per week per participant. Change in daily steps walked at the 6-week follow-up was +497 (SD 2171) in the intervention group and –861 (SD 2534) in the control group (95% CI 263-2451, P=.02). Significant intervention effects were observed at the 6-week follow-up in EE (+43.94 kcal, 95% CI 43.93-309.98, P=.01), DSA (–7.79 minutes, 95% CI –55.01 to –7.01, P=.01), DMA (+6.31 minutes, 95% CI 6.01-51.20, P=.01), weight (–0.56 kg, 95% CI –1.78 to –0.15, P=.02), self-efficacy (95% CI 0.30-4.79, P=.03), emotional QOL score (95% CI 0.01-0.54, P=.04), and angina frequency (95% CI 8.57-35.05, P=.002). Significant benefits in angina frequency (95% CI 1.89-29.41, P=.02) and social QOL score (95% CI 0.05-0.54, P=.02) were also observed at the 6-month follow-up.

Conclusions

An Internet-based secondary prevention intervention could be offered to those with angina. A larger pragmatic trial is required to provide definitive evidence of effectiveness and cost-effectiveness.

Trial Registration

International Standard Randomized Controlled Trial Number (ISRCTN): 90110503; http://www.controlled-trials.com/ISRCTN90110503/ISRCTN90110503 (Archived by WebCite at http://www.webcitation.org/6RYVOQFKM).     

Fluorinated poly(propylenimine) dendrimers as gene vectors

The use of poly(propylenimine) (PPI) dendrimers as gene delivery vectors is limited by their low transfection efficacy and serious cytotoxicity. In this study, we prepare a series of efficient and low cytotoxic gene vectors based on PPI dendrimers using a facile fluorination strategy. Fluorinated G3, G4, and G5 PPI dendrimers show comparable or superior transfection efficacies to six representative transfection reagents such as Lipofectamine 2000, jetPEI, branched poly(ethyleneimine), SuperFect, PolyFect, as well as arginine-modified dendrimer on both HEK293 and HeLa cells. These fluorinated PPI dendrimers exhibit low cytotoxicity on the transfected cells because they achieve optimal transfection efficacy at extremely low nitrogen to phosphorus (N/P) ratios. In addition, the synthesized materials show high transfection efficacy on 3D multicellular spheroids. These results demonstrate that fluorination is a promising strategy to improve the transfection efficacy of PPI dendrimers while reducing the cytotoxicity of these cationic polymers.