平板运动试验中室性早搏ST段下移诊断冠状动脉病变的价值

探讨平板运动试验中室性早搏(VPCs)ST段下移程度对反映冠状动脉(简称冠脉)病变的价值。将休息和平板运动试验中均发生VPCs并且在3个月内进行冠脉造影的92例患者按冠脉造影结果分成冠心病组和非冠心病组,比较两组VPCsST段下移程度,下移程度与冠脉狭窄程度的关系以及VPCsST段下移诊断冠心病的价值。结果:冠心病组运动中VPCsST段下移及ST/R均大于非冠心病组。其中ST/R>10%对冠心病诊断灵敏度为91%,特异度为75%;对单支、2支、3支血管病变诊断灵敏度分别为84%、91%、100%。冠脉狭窄≥90%组运动中VPCsST段下移和ST/R大于狭窄为50%~69%组。结论:运动试验中VPCsST段下移可作为诊断冠心病的有效参考指标,其下移程度可能与冠脉狭窄程度有关。     

Engineering tropane biosynthetic pathway in Hyoscyamus niger hairy root cultures

Scopolamine is a pharmaceutically important tropane alkaloid extensively used as an anticholinergic agent. Here, we report the simultaneous introduction and overexpression of genes encoding the rate-limiting upstream enzyme putrescine N-methyltransferase (PMT) and the downstream enzyme hyoscyamine 6 beta-hydroxylase (H6H) of scopolamine biosynthesis in transgenic henbane (Hyoscyamus niger) hairy root cultures. Transgenic hairy root lines expressing both pmt and h6h produced significantly higher (P < 0.05) levels of scopolamine compared with the wild-type and transgenic lines harboring a single gene (pmt or h6h). The best line (T(3)) produced 411 mg/liter scopolamine, which was over nine times more than that in the wild type (43 mg/liter) and more than twice the amount in the highest scopolamine-producing h6h single-gene transgenic line H(11) (184 mg/liter). To our knowledge, this is the highest scopolamine content achieved through genetic engineering of a plant. We conclude that transgenic plants harboring both pmt and h6h possessed an increased flux in the tropane alkaloid biosynthetic pathway that enhanced scopolamine yield, which was more efficient than plants harboring only one of the two genes. It seems that the pulling force of the downstream enzyme (the faucet enzyme) H6H plays a more important role in stimulating scopolamine accumulation in H. niger whereas the functioning of the upstream enzyme PMT is increased proportionally. This study provides an effective approach for large-scale commercial production of scopolamine by using hairy root culture systems as bioreactors.     

A genomewide study identifies the Wnt signaling pathway as a major target of p53 in murine embryonic stem cells

Both p53 and the Wnt signaling pathway play important roles in regulating the differentiation of mouse embryonic stem cells (mESCs). However, it is not known whether they directly and/or functionally crosstalk in mESCs. Here we report a surprising antidifferentiation function of p53 in mESCs through directly regulating the Wnt signaling pathway. A chromatin-immunoprecipitation-based microarray (ChIP-chip) and gene expression microarray assays reveal that the Wnt signaling pathway is significantly (P value, 0.000048) overrepresented in p53-regulated genes in mESCs. The expression of five Wnt ligand genes is robustly induced by various genotoxic and nongenotoxic insults in a p53-dependent manner. Moreover, the induction of these Wnt genes is greatly attenuated in mouse embryonic fibroblast (MEF) cells and ESC-derived neural stem/progenitor cells, suggesting that the induction is mESC specific. It is established that the activation of the Wnt signaling pathway inhibits the differentiation of mESCs. Consistent with this notion, we detected an antidifferentiation activity from the conditioned medium (CM) collected from UV (UV)-treated mESCs. This antidifferentiation activity can be lowered by either the addition of Wnt antagonists into the CM or the reduction of p53 levels in UV-treated mESCs. Therefore, reminiscent of its dual functions on death and survival in somatic cells, p53 appears to regulate both prodifferentiation and antidifferentiation programs in mESCs. Our findings uncover a direct and functional connection between p53 and the Wnt signaling pathway, and expand the catalog of p53 regulated genes in mESCs.     

野生型p53对肝癌细胞POLD1基因表达及细胞恶性表型的影响

目的:探讨野生型p53对人肝癌细胞SMMC-7721细胞增殖和细胞恶性表型影响的一种可能机制,方法:设计并构建p53特异性小干扰shRNA绿色荧光真核表达质粒(p53-siRNA)和表达EGFP-p53融合蛋白的p53绿色荧光真核增强表达质粒(pEGFP-p53),通过脂质体Lipofection-2000介导转染,将...     

口袋书联合歌诀教学法提高规培护士耳穴定位能力的研究

目的 探讨口袋书联合耳穴歌诀教学法对提高规培护士基础耳穴定位能力的效果,为临床提供一种新的教学方法.方法 采用前后对照研究方法,选取本院60名来源于省内外某3所西医护理学院毕业需要的规培护士,2018年入职的30名规培护士为对照组,2019年入职的30名规培护士为试验组.对照组采用常规教学方法,试验组在对照组基础上采用...     

Review of a new bone tumor therapy strategy based on bifunctional biomaterials

INTRODUCTION Bone tumors involve the invasion of tumors into bone tissue and are classified as either primary tumors or metastatic tumors. Osteosarcoma is a wel...     

氟对机体的生理与毒理作用研究进展

氟是自然界广泛分布的元素之一,它以各种化学形态广泛分布于土壤、水和空气中,几乎所有的动植物体内均含氟,在自然界的氟常以无机或有机化合物形式存在。随着科学的发展、社会的进步,纯净水、直饮水已走进寻常百姓家中,走进学校、工厂机关,给人们带来便利。但也有学者提出,纯净水对人