Regulatory mechanisms of atrial fibrotic remodeling in atrial fibrillation

Electrical, contractile and structural remodeling have been characterized in atrial fibrillation (AF), and the latter is considered to be the major contributor to AF persistence. Recent data show that interstitial fibrosis can predispose to atrial conduction impairment and AF induction. The interplay between cardiac matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitors of MMPs (TIMPs), is thought to be critical in atrial extracellular matrix (ECM) metabolism. At the molecular level, angiotensin II, transforming growth factor-beta1, inflammation and oxidative stress are particularly important for ECM dysregulation and atrial fibrotic remodeling in AF. Therefore, we review recent advances in the understanding of the atrial fibrotic process, the major downstream components in this remodeling process, and the expression and regulation of MMPs and TIMPs. We also describe the activation of bioactive molecules in both clinical studies and animal models to modulate MMPs and TIMPs and their effects on atrial fibrosis in AF.     

Differential regulation of collagen types I and III expression in cardiac fibroblasts by AGEs through TRB3/MAPK signaling pathway

Advanced glycation end products (AGEs) play an important role in collagen deposition in diabetic cardiomyopathy. TRB3, a mammalian homolog of Drosophila tribbles, functions to increase glucose intolerance and regulates cell proliferation. We demonstrated that AGEs induce collagen type I expression but inhibit collagen type III expression, accompanied by increased TRB3 expression. Furthermore, the collagen type I induced byAGEs was down-regulated after inhibition of ERK and p38-MAPK, the collagen type III reduced by AGEs was up-regulated after inhibition of ERK. The expression of collagen types I and III regulated by AGEs through MAPK was partly reversed after treatment with TRB3 siRNA. It suggests that the TRB3/MAPK signaling pathway participates in the regulation of collagen types I and III by AGEs and may provide new therapeutic strategies for diabetic cardiomyopathy. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 08 May 2008; received after revision 25 June 2008; accepted 22 July 2008 M. Tang, M. Zhong: These two authors contributed equally to this work.     

组织培养技术在植物育种中的应用

总结了近些年来组织培养技术在植物育种上的应用，同时对这一技术的发展进行了展望．     

老年性退行性心瓣膜病302例临床分析

回顾性分析了308例老年性退行性心脏瓣膜病（SCVC），SCVC的临床特点。结果显示：主动脉瓣区病变率高（90．7％），与其他瓣膜区比较，P＜0．01；临床症状体征无特异性，杂音检出率低（主动脉瓣区仅为23．8％）；心律失常（47．7％）和心功能不全（47．1％）发生率高轨病率随着年龄的增大而增加。上述表明，SCVC对本病诊断价值较小 波检查是诊断本病的重要方法。     

轮槽铣刀闭式滚挤成对锻造

介绍一一种新型的轮槽铣刀锻造工艺－－以两件刀坯相挤成型，克服了单件滚挤端裂、废品率高的缺点，由于坯料逐渐缩径，使得金属组织密实，碳化物分布均匀，该铸造工艺不仅提高了刀具的性能和使用寿命，而且节省了钢材，提高了经济效益。     

磁场对哺乳动物脑组织、脑细胞及其超微结构影响的研究

用均匀交变磁场作用于小鼠后，对其进行了脑组织，脑细胞及其超微结构的形态学分析，结果表明，该磁场条件无损伤作用。     

从石蜡包埋组织高效提取RNA的优化及Shh的RT-PCR检测

从石蜡包埋组织中提取高质量的RNA是对肿瘤实体组织进行分子生物学研究的重要方法之一．利用人的胃肠道肿瘤材料，通过蛋白酶K消化，经酚-氯仿、异戊醇抽提去蛋白及异丙醇沉淀，优化了1套从石蜡包埋组织中提取RNA的方法，提高了所提取RNA的质量和产量．所得RNA经电泳检测，并进行RT-PCR扩增Shh(sonic hedgehog)信号分子，结果良好．故认为此提取RNA的方法值得推广．     

血管生成素-1基因治疗兔心肌梗塞的实验观察

探讨血管生成素_1(Ang1)基因经重组腺病毒介导转移促进心肌缺血区血管形成的作用 .应用共转染 2 93细胞 ,制备纯化Ang1重组腺病毒及LacZ重组腺病毒 .将Ang1重组腺病毒及LacZ重组腺病毒直接注射感染兔冠状动脉结扎后缺血心肌细胞 ,分别应用RT_PCR方法及X_gal染色测定外源基因在转导心肌中的表达 ,用免疫组化及冠状动脉造影方法观察缺血心肌内血管生长及侧支循环形成的情况 ,并用心脏超声检查观测了注射Ang1重组腺病毒后心功能变化 .结果显示重组腺病毒直接注射感染兔缺血心肌后能有效表达目的基因 ,X_gal染色显示LacZ基因转移后第 3、7、14、2 8d注射部位心肌均见蓝染 ,尤以 7d明显 ,RT_PCR测定提示Ang1基因在转移后第 3d心肌中即有表达 ,7、14d仍呈阳性表达 .转移 2 8d后新生毛细血管密度及侧支循环形成明显高于对照组 (P <0 .0 1) .心肌梗塞发生后各组的心功能随时间延长均有所改善但 14d内各组间无明显差异 ,2 8d后Ang1组改善幅度明显高于对照组 (P <0 .0 1) .本实验表明腺病毒介导的Ang1基因在兔缺血心肌中能有效表达 ,促进新生血管形成 ,改善心脏功能 .     

培养基及6BA与蔗糖浓度对白桦茎叶去分化率的影响

在培养白桦试管苗的去分化阶段进行不同培养基、6BA浓度、蔗糖浓度对茎、叶去分化率影响的比较试验，结果表明：以MS＋NAA0．1mg／L＋IBA0．5mg／L为基本培养基时，茎、叶的去分化效果较好，并且添加的蔗糖浓度越低，越适于茎的分化，浓度较高，越适于叶的分化。     

杉木茎段形成层组织cDNA文库的构建

为了分离和克隆与杉木木材形成相关的重要基因,笔者以杉木2~3年生枝条,5~6月份形成层活动期的茎段形成层组织为材料,用表达型噬菌体载体ZAP构建了cDNA文库。文库宿主菌为E.coliXL1-Blue,亚克隆空菌为E.coliXLOLR。试验结果表明:初级文库的库容量达到6.1×105pfu,扩增文库的滴度达到5.2×109pfu/mL,重组率达到95%,插入片段大小在0.5~3.0 kb。