Formaldehyde induces toxic effects and regulates the expression of damage response genes in BM-MSCs

In this study, we assessed the toxic effects of formaldehyde （FA） on mouse bone marrow mesenchymai stem cells （BM- MSCs）. Cytotoxicity was measured by using MTT assay. DNA strand breakage was detected by standard alkaline comet assay and comet assay modified with proteinase K （PK）. DNA-protein crosslinks （DPCs） were detected by KCI-SDS precipitation assay. We found that FA at a con- centration from 75 to 200 μM inhibited cell survival and induced DPCs over 125 μM. The PK-modified comet assay showed that FA-induced DNA strand breakage was increased in a dose-dependent manner from 75 to 200 μM. On the other hand, standard alkaline comet assay showed that DNA strand breakage was decreased with FA concen- tration over 125 μM. We confirmed by using Pearson cor- relation that there was a negative linear correlation between DPCs and survival rate （r = -0.987, P 〈 0.01） and positive linear relationships between DPCs and （i） sister chromatid exchange and （ii） micronucleus （r = 0.995, P〈 0.01; r = 0.968, P〈 0.01）. DNA damage RTz profiler polymerase chain reaction array was used to investigate the changes in the expression of damage response genes. Xpa and Xpc of the nucleotide excision repair pathway and Brca2, Rad51, and Xrcc2 of the homologous recombination pathway were all up-regulated in both 75 and 125 μM FA. However, the same genes were down-regulated with 175 μM FA. The expressions of Chekl and Husl, which are involved in cell cycle regulation, were altered in the same manner with 75, 125, and 175 μM FA. These results indicated that Xpa, Xpc, Brca2, Rad51, Xrcc2, Chekl, and Husl were essential for the BM-MSCs to counteract the effects of FA.     

Association of human leukocyte antigen E polymorphism with human cytomegalovirus reactivation in Chinese burn patients

The seroprevalence of human cytomegalovirus （HCMV） in adults increased steadily from 55% in developed countries to over 90% in developing countries like China [1]. As all her- pesviruses, HCMV establishes lifelong latency after primary infection. In immunocompetent individuals, host immune responses prevent the development of overt HCMV diseases. However, in immunoeompromised people who suffer from burn injuries, HCMV reactivation has been shown to lead to significant diseases with considerable morbidity and mortal- ity [2-4]. Recently, increasing evidence has suggested that HCMV reactivation might have been considerably underesti- mated in burn patients [5,6]. Review of the available litera- ture identifies 〉50% of HCMV antibody-positive burn patients may reactivate this virus [5,6]. Although the exact mechanisms of HCMV reactivation are still not clearly under- stood, the immune system and host genetics are thought to be the non-behavioral factors determining the acquisition of a reactivation.     

Jagged-1/Notch3 signaling transduction pathway is involved in apelin-13-induced vascular smooth muscle cells proliferation

The apelin/apelin receptor （APJ, apelin-angiotensin receptor-like 1） system is a newly deorphanized G protein- coupled receptor system. Both apelin and APJ that are important regulatory factors are expressed in the cardio- vascular system. Our previous studies demonstrated that apelin-13 significantly stimulated vascular smooth muscle cell （VSMC） proliferation. In this paper, our data sug- gested that the Jagged-l/Notch3 signaling transduction pathway is involved in apelin-13-induced VSMC prolifer- ation by promoting the expression of Cyclin D1. Results indicated that apelin-13 stimulates the proliferation of VSMC and the expression of Jagged-1 and Notch3 in con- centration- and time-dependent manners. The increased expression of Jagged-1 and Notch3 induced by apelin-13 could be abolished by extracellular signal-regulated protein kinase （ERK） blockade. PD98059 （ERK inhibitor） can inhibit the activation of Jagged-I/Notch3 induced by apelin- 13. Down-regulation of Notch3 using small interfering RNA inhibits the expression of Cyclin DI and prevents apelin- 13-induced VSMC proliferation. In conclusion, Jagged-I/ Notch3 signaling transduction pathway is involved in VSMC proliferation induced by apelin-13.     

Novel Natural Allelic Variations at the Rht-1 Loci n Wheat

Plant height is an important agronomic trait. Dramatic increase in wheat yield during the ＂green revolution＂ is mainly due to the widespread utilization of the Reduced height （Rht）-1gene. We analyzed the natural allelic variations of three homoeologous loci Rht-A1, Rht-B1, and Rht-D1 in Chinese wheat （Triticum aestivum L.） micro-core collections and the Rht-B1/D1 genotypes in over 1,500 bred cultivars and germplasms using a modified EcoTILLING. We identified six new Rht-A1 allelic variations （Rht-Alb-g）, eight new Rht-B1 allelic variations （Rht-Blh-o）, and six new Rht-D1 allelic variations （Rht-Dle-j）. These allelic variations contain single nucleotide polymorphisms （SNPs） or small insertions and deletions in the coding or uncoding regions, involving two frame-shift mutations and 15 missenses. Of which, Rht-Dle and Rht-Dlh resulted in the loss of interactions of GID1-DELLA-GID2, Rht-Blicould increase plant height. We found that the Rht-Blh contains the same SNPs and 197 bp fragment insertion as reported in Rht-Blc. Further detection of Rht-Blh in Tibet wheat germplasms and wheat relatives indicated that Rht-Blc may originate from Rht-Blh. These results suggest rich genetic diversity at the Rht-1 loci and provide new resources for wheat breeding.     

血管内皮细胞生长因子基因-2578C/A多态性与中国北方汉族人群银屑病易感性的相关性研究

目的:探讨血管内皮细胞生长因子(vascular endothelial cell growth factor,VEGF)基因-2578 C/A单核苷酸多态性位点与中国北方地区银屑病易感性的相关性.方法:随机收集2005年10月至2007年5月在哈尔滨医科大学附属一、二院皮肤科门诊就诊的246例寻常型银屑病患者(实验组)和271名正常对照个体(对照组)的外周静脉血,使用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法分析VEGF-2578 C/A多态位点基因型,并进行统计学分析.结果:在实验组中,VEGF-2578 C/A等位基因频率分别为74.80％、25.20％;在正常对照组中,VEGF-2578 C/A等位基因频率分别为76,59％、23.41％,两组VEGF-2578 C/A多态位点基因型的分布差异无统计学意义(P＞0.05).结论:VEGF基因-2578 C/A的多态性与中国北方汉族人群银屑病的易感性无明显相关性.     

NDRG2在大鼠肺缺血再灌注损伤中的表达

目的:通过建立大鼠肺缺血再灌注损伤(Lung ischemia-reperfusion injury,LIRI)模型,观察肺缺血再灌注损伤后,肺组织中N-myc下游调节基因2(N-myc downstream regulated gene,NDRG2)表达水平的变化.方法:将70只健康成年雄性SD大鼠随机分成对照组(C)、缺血组(I)、缺血再灌注组(I/R)(后两组各含3个亚组),每组10只.麻醉固定大鼠,颈部切口行气管插管.右侧开胸,肺缺血组依次分别选择游离夹闭右肺门(即右主支气管,右肺动、静脉)缺血30 min、60 min、120 min后,麻醉处死大鼠获取肺组织.肺缺血再灌注组同样选择游离夹闭右肺门,于夹闭右肺门60 min后松开,分别取再灌注30 min、60 min、120m in后麻醉处死大鼠获取肺组织样本.采用免疫组化对肺组织NDRG2进行蛋白定位检测、RT-PCR对肺组织NDRG2 mRNA含量进行检测、Western-blot对肺组织NDRG2蛋白含量进行检测.结果:肺缺血组与对照组比较,肺组织NDRG2的表达无明显变化(P＞0.05);肺缺血再灌注组与对照组比较,NDRG2蛋白含量和mRNA表达量逐渐下降,在60 min时达最低,之后又有所回升,但仍低于对照组(P＜0.05).结论:肺缺血再灌注损伤可下调肺组织中NDR G2的表达含量,NDRG2可能是肺缺血再灌注损伤的靶向调控位点.     

儿童急性淋巴细胞白血病特异性标记物的精准检测方法研究

目的：T细胞和免疫球蛋白重链基因重排是微小残留病灶水平的特异性标记物,而微小残留病灶的水平与儿童急性淋巴细胞白血病的复发强烈相关。应用传统的聚合酶链式反应方法来监测IgH／TCR基因重排不仅耗时、耗人力,而且敏感度较低。本研究旨在探索一种更为高效和敏感与实用的监测IgH／TCR基因重排的精准检测方法。方法：应用多重PCR技术检测26个患有急性淋巴细胞白血病的儿童的外周血样品中的标记物,这些儿童是在中国哈尔滨市最近两年内被诊断的患者。分别应用基因扫描和毛细血管电泳方法检测IgH（FRI,FRII,FRⅢ）／TCR（TCRB,TCRγ）基因重排和分析PCR产物的片段。结果：IgH／TCR基因重排和对IgH基因重排的阳性率分别为92．3％和75％,在26个病例中,4个复发病人的IgH的三个片段（FRI,FRII,FRⅢ）基因重排显示阳性。进一步分析显示复发与ign基因重排呈线性相关。结论：实验与临床应用表明,基因扫描这种方法对于IgH／TCR基因重排的检测是可靠的、实用的,因而可用于儿童急性淋巴细胞白血病的诊断和随访。     

《自然-通讯》：科学家发明可激活抑癌基因物质

蛋白质P53是一种重要的抑癌基因,又被称为癌变克星。它能促使受损的细胞自杀,防止产生癌变,但这个基因常常失效。凯泽等人利用计算机模拟和实验室检验发现,Stictin能够部分激活癌细胞中处于休眠状态的蛋白质P53,使其重新发挥作用。     

纳米金-聚乙烯亚胺基因载体的制备

目的:基因方法治疗癌症近年来取得了很大的突破,因此基因载体的构建显得尤为重要.其中纳米基因载体合成简单,成本低廉,并能够包裹、浓缩、保护核苷酸使其免受核酸酶降解,因此纳米材料广泛地应用于基因输送.我们拟开展聚乙烯亚胺-纳米金基因载体的制备及其表征.方法:采用层层包裹技术制备基因载体,首先通过柠檬酸钠还原法制备纳米金颗粒后,应用11-巯基十一烷酸对金颗粒进行修饰,使其表面带有羧基,然后进一步将带有氨基的低分子量聚乙烯亚胺与羧基进行连接.应用动态光散射(DLS),紫外可见光谱(UV)和透射电子显微镜(TEM)对构建的纳米基因载体进行表征.结果:成功制备了聚乙烯亚胺-纳米金基因载体,检测表明每一步制备出的产物纳米尺寸在20-30nm之间,液体均匀稳定,分散系数(PDI)在0.2以下,Zeta电位测定表明,每步的产物电荷变化与外层包裹的反应物有关.尽管金颗粒外层包裹聚乙烯亚胺,但是总体上纳米载体尺寸没有发生太大的变化,TEM检测表明每一步形成了均匀的、单分散的、球状的纳米颗粒.结论:我们通过层层包裹技术成功制备了聚乙烯亚胺-纳米金基因载体,在进一步开展的生物活性的检测中,希望通过纳米载体的携带作用,将基因转染进靶细胞,从而检测相关基因对靶细胞的沉默作用,提高基因药物的应用,为开发新型基因药物提供基础.     

中国汉族人群CXCR2基因＋1235C/T多态与急性冠脉综合征的关联研究

目的：炎症反应在动脉粥样斑块变化的病理过程中发挥着重要的作用。本研究探讨CXCR2基因＋1235 C/T单核苷酸多态与中国汉族人群急性冠脉综合征发病的相关关系。方法：本研究采用聚合酶链反应-限制性片段长度多态性方法对675例急性冠脉综合征的患者和636例对照组进行检测,分析CXCR2基因＋1235 C/T单核苷酸多态的基因型和等位基因频率的分布情况,同时收集济南军区总医院心内科经冠脉造影证实为阳性的急性冠脉综合征患者360例及对照者360例,对上述关联分析的结果进行复制实验的印证。结果：CXCR2基因＋1235 C/T单核苷酸多态三种基因型（CC型,CT型和TT型）在急性冠脉综合征组分布频率分别为39.3%,45.3%和15.1%,在对照组分别为41.7%,47.2%和11.1%,CXCR2基因＋1235 C/T基因型和等位基因频率对照组和急性冠脉综合征组之间存在统计学差异（P〈0.05）。Logistic回归校正性别、年龄、体重指数、吸烟、高血压、高脂血症、糖尿病等冠心病的易患因素后,CXCR2基因＋1235 C/T多态与急性冠脉综合征的发病存在相关关系（P〈0.05）。结论：CXCR2基因＋1235 C/T多态与急性冠脉综合征发病存在相关关系,CXCR2基因＋1235 C/T多态可能是中国汉族人群急性冠脉综合征发病的独立危险因子。