大鼠骨髓间充质干细胞向多巴胺样神经细胞分化

目的探索大鼠骨髓间充质干细胞向多巴胺能样细胞分化。方法全骨髓培养法分离大鼠骨髓间充质干细胞;体外培养至第3代,用碱性成纤维细胞生长因子,抗坏血酸和表皮生长因子诱导分化;免疫荧光法鉴定胞质中的多巴胺神经元相关蛋白的表达;RT-PCR鉴定多巴胺神经元相关基因的表达;ELISA法检测上清及胞质中的多巴胺。结果诱导后,免疫荧光法检测到诱导后的细胞表达多巴胺神经元相关蛋白:酪氨酸羟化酶、多巴胺转运蛋白和神经核蛋白;RT-PCR检测到诱导后的细胞表达多巴胺神经细胞相关基因TH、AADC;ELISA法检测到诱导后的上清及胞质中有多巴胺分泌。结论间充质干细胞具有向多巴胺能样细胞分化的能力。     

Multiple imputation technique applied to appropriateness ratings in cataract surgery

Missing data such as appropriateness ratings in clinical research are a common problem and this often yields a biased result. This paper aims to introduce the multiple imputation method to handle missing data in clinical research and to suggest that the multiple imputation technique can give more accurate estimates than those of a complete-case analysis. The idea of multiple imputation is that each missing value is replaced with more than one plausible value. The appropriateness method was developed as a pragmatic solution to problem of trying to assess "appropriate" surgical and medical procedures for patients. Cataract surgery was selected as one of four procedures that were evaluated as a part of the Clinical Appropriateness Initiative. We created mild to high missing rates of 10%, 30% and 50% and compared the performance of logistic regression in cataract surgery. We treated the coefficients in the original data as true parameters and compared them with the other results. In the mild missing rate (10%), the deviation from the true coefficients was quite small and ignorable. After removing the missing data, the complete-case analysis did not reveal any serious bias. However, as the missing rate increased, the bias was not ignorable and it distorted the result. This simulation study suggests that a multiple imputation technique can give more accurate estimates than those of a complete-case analysis, especially for moderate to high missing rates (30 - 50%). In addition, the multiple imputation technique yields better accuracy than a single imputation technique. Therefore, multiple imputation is useful and efficient for a situation in clinical research where there is large amounts of missing data.     

北京地区汉族人群DNA修复基因XPD单核苷酸多态性与肺癌及食管癌风险的研究

目的：研究核苷酸切除修复基因XPD单核苷酸多态性与北京地区汉族人群肺癌及食管癌风险的关系。方法：采用以医院患者为基础的病例－对照研究方法，包括正常对照383人，肺癌患者351例，食管癌患者325例。以聚合酶链反应－限制性片段长度多态性方法分析了XPD基因Asp312 Asn和Lys751Gln多态性，比较不同基因型与肺癌及食管癌风险的关系，并探讨吸烟与基因多态交互作用对患癌风险的影响。结果：与携带312 Asp/Asp基因型者比较，携带至少1个312Asn等位基因者（即Asp/Asn和Asn/Asn基因型）罹患肺鳞癌的风险增加1．8倍（95％CI1．10－2．93），而与肺腺癌无关（校正的比值比为1．07，95％CI0．55－2．08）。分层分析显示，风险型等位基因312Asn和751Gln与吸烟有明显的交互作用。吸烟剂量≥29包／年且携带312Asn或751Gln者罹患肺鳞癌的风险最高，校正的比值比分别为12．44（95％CI4．97－31．17）和10．74（95％CI4．51－25．57）。XPD基因Asp312Asn和Lys751Gln多态与食管鳞癌风险无关。结论：XPD基因Asp312Asn和Lys751Gln多态是地区汉族人群肺鳞癌遗传易感因素，而与肺腺癌以及食管鳞癌风险无关，可能反映了不同组织学类型肺癌以及肺癌和食管癌之间的病因学差异。     

Three-dimensional forward solver and its performance analysis for magnetic resonance electrical impedance tomography (MREIT) using recessed electrodes

In magnetic resonance electrical impedance tomography (MREIT), we try to reconstruct a cross-sectional resistivity (or conductivity) image of a subject. When we inject a current through surface electrodes, it generates a magnetic field. Using a magnetic resonance imaging (MRI) scanner, we can obtain the induced magnetic flux density from MR phase images of the subject. We use recessed electrodes to avoid undesirable artefacts near electrodes in measuring magnetic flux densities. An MREIT image reconstruction algorithm produces cross-sectional resistivity images utilizing the measured internal magnetic flux density in addition to boundary voltage data. In order to develop such an image reconstruction algorithm, we need a three-dimensional forward solver. Given injection currents as boundary conditions, the forward solver described in this paper computes voltage and current density distributions using the finite element method (FEM). Then, it calculates the magnetic flux density within the subject using the Biot-Savart law and FEM. The performance of the forward solver is analysed and found to be enough for use in MREIT for resistivity image reconstructions and also experimental designs and validations. The forward solver may find other applications where one needs to compute voltage, current density and magnetic flux density distributions all within a volume conductor.     

趋化因子受体CCR5反义RNA在真核细胞中的表达

目的 构建趋化因子受体CCR5反义RNA真核表达载体并获取重组假病毒颗粒以用于抗HIV-1研究，方法 用RT-PCR法从健康人外周血单个核细胞（PBMCs)中获得趋化因子受体CCR5翻译起始区的基因片段，并以正、反两个方面定向插入到真核表达载体pLXSN上，重组载体用脂质体转染剂（lipofectAMINE)转染PA317包装细胞，抗-G418克隆的细胞上清经逆转录后用荧光定量PCR（FQ-PCR）测定假病毒滴度，进一步感染NIH/3T3细胞。结果 CCR5正、反义RNA的真核表达载体。经PA317细胞包装形成的假病毒颗粒已成功地感染NIH/3T3细胞，目的基因在该细胞中得到整合与表达。结论 从PBMCs中获得的趋化因子受体CCR5基因片段通过逆转录病毒载体可转移至真核细胞中并得到表达，为进一步研究CCR5反义RNA的抗HIV-1作用奠定了基础。     

Postmenopausal oral estrogen therapy and blood pressure in normotensive and hypertensive subjects: the Estrogen in the Prevention of Atherosclerosis Trial

OBJECTIVE: To determine if 17beta-estradiol increases blood pressure in postmenopausal women. DESIGN: A total of 222 healthy postmenopausal women were randomly assigned to either 1 mg micronized 17beta-estradiol daily or placebo for 2 years. Blood pressure measurements were obtained every other month and common carotid artery intima-media thickness measured every 6 months. Statistical analyses comparing longitudinal changes in systolic and diastolic blood pressure between treatment groups used a mixed general linear model including interaction terms to evaluate variations by age or estradiol level. RESULTS: Both placebo and estradiol groups showed small declines in systolic and diastolic blood pressure during the trial among the normotensive subjects and subjects on antihypertensive medications. However, the decline did not differ significantly between the groups. Treatment effects on systolic blood pressure differed significantly by the age of the subject (interaction P value = 0.04) with younger women on estradiol showing on average a rise in systolic blood pressure, and older women a decline. The association between serum estradiol level and systolic blood pressure showed a similar modification with age (P = 0.03). Changes in systolic blood pressure in women on estradiol were positively correlated with intima-media thickness progression (P = 0.03). CONCLUSIONS: Overall, 17beta-estradiol did not influence changes in blood pressure in normotensive or hypertensive women. The effect of 17beta-estradiol treatment on systolic blood pressure may be influenced by a woman's age. Estradiol may increase systolic blood pressure in younger postmenopausal women, while having the opposite effect in older postmenopausal women.     

兔肌源性干细胞的生物学特性及表型研究

目的:探讨兔肌源性干细胞(MDSCs)的分离及特征和表型研究。方法:取1.5月龄新西兰兔大腿肌肉，采用差速贴壁分离Preplate技术，分别用Ⅺ胶原酶、dispase蛋白酶以及胰蛋白酶分步消化肌肉，并用差速贴壁法分离晚期贴壁的细胞，流式细胞仪(FCM)、免疫细胞化学以及Western blotting等检测初步确定细胞表型。结果:进行连续6 d的差速贴壁分离。第3 d开始得到较多量的圆形或短梭形细胞，簇样生长，体积明显小于骨骼肌细胞及其它杂细胞，10 d左右汇合，有极强的融合生长倾向。细胞在汇合度<30%传代可较好地保持原形态，流式细胞仪检测示MDSCs>80%为desmin+，>70%为Bcl-2+，>95%为CD45-，免疫细胞化学定性示desmin+。Western blotting检测显示随着细胞的纯化，α-SMA表达越来越弱。而细胞高汇合度(>50%)或低血清培养时极易融合成肌管或肌细胞链，skeletal myosin+。结论:MDSCs具有desmin、Bcl-2高水平表达和CD45极低水平表达的特性，具有多向分化能力的MDSCs是组织工程研究的一种新型种子细胞。     

先天性巨结肠患者人类巨细胞病毒UL144基因多态性的研究

目的研究人类巨细胞病毒（human cytomegalovirus,HCMV）UL144基因在先天性巨结肠（Hirschsprung＇s disease,HD）临床株中的多态性,探讨HCMV UL144基因多态性与致病性之间的关系.方法随机选取53个先天性巨结肠患儿痉挛段结肠手术标本及经荧光定量PCR方法检测HCMV DNA为阳性的4个HD患儿的尿标本,对照组为无症状或仅有皮肤轻度黄疸的6个尿标本.应用巢式聚合酶链反应的方法,扩增HCMV UL144基因开放阅读框架（ORF）,扩增阳性的临床株进行双向DNA测序,最后通过DNAclub、Bioedit、DNAstar、GeneDoc等软件进行分析.结果23份HD痉挛段肠组织（46%）及4份尿标本HCMV UL144基因扩增阳性,并且完成测序.种系进化树分析结果显示25个HD患儿的DNA序列分为3个基因型,G1A型64.0%,G2型24%,G3型12%.与对照组比较,经χ^2检验,χ^2=10.93,P为0.012;其中HD临床株G1A和G3型基因经Fisher检验,P为0.015,差异具有统计学意义.全结肠型、长段型及普通型HD分散分布于UL144各个基因型中.结论HD与HCMV感染有关,HCMV可能是HD的病因之一;在HD患儿中,HCMV感染以UL144基因G1A型为主;HD的临床分型与HCMV UL144基因分型无关.     

Forensic characteristics and phylogenetic analysis of 23 Y-STR loci in the Miao population from Guizhou province,southwest China

Background: Investigation of haplotype/allele frequency data of Y-STR loci in ethnically diverse populations is essential for forensic reference database construction and genetic application. However, the population genetic characteristics of the Chinese Miao minority from Guizhou Province remain uncharacterised.

Aim: To assess forensic characteristics for 23 Y-Chromosomal STR loci in Guizhou Miao and explore population genetic relationships with geographically neighbouring populations.

Subjects and methods: Twenty-three Y-Chromosomal STRs were genotyped using the Powerplex^® Y23 system in 103 unrelated Chinese Miao males from Guizhou Province, southwest China. Haplotypes and forensic parameters were obtained. Population relationships of Guizhou Miao with others were revealed using AMOVA and an MDS plot.

Results: A total of 96 haplotypes were identified with overall haplotype diversity (HD) and discrimination capacity (DC) of 0.9985 and 0.9320, respectively. Genetic differentiation was observed with most of the comparison populations, prominently for Guizhou Shui.

Conclusion: The 23 Y-STR loci were highly polymorphic and discriminating in the Guizhou Miao population and could be used for forensic practice and population genetic studies. Population relationship analysis revealed Guizhou Miao had a close genetic relationship with geographically close Guizhou Gelao, as well as Han majorities derived from different regions.     

器官培养在研究人食管上皮癌变中的应用

将组织块置于明胶海绵上,摇摆器官培养,4～6周后成人食管粘膜仍保持良好的结构形态,具有活跃生长的上皮细胞和良好的腺体结构;将组织块贴壁,静置外植块—细胞培养,成人食管粘膜和胎儿食管组织块可存活2～3个月,提供大量生长旺盛的上皮细胞。成人食管癌旁粘膜培养利于观察细胞癌前改变,可能较易于诱发癌变;胎儿食管具有正常背景,利于研究细胞癌变的全过程.二者配合可组成研究人食管上皮癌变的完整体外实验系统。