Exploring the developmental potential of adult mammalian somatic cells

In the traditional ciews on developmental biology,the process of a mammal from a zygote to an adult individual follows continuous changes of space and time environments and is the result of different expressions of target genes.It has long been known that this process is irreversible and the terminal differentiated adult cells,such as cardiac myocytes andneurons,will not divide and differentiate.But recent reports on the two hottest fields—cloning medicine and stem cell biology doubted these concepts.This may lead to a further understanding of the potentiality of mammal development and may provide great chances for commercial andd clinical practice.     

Effect of the control proliferation of astrocyte on the formation of glial scars by antisenseGFAP retrovirus

Astrocytes play an important role in the formation of glial scars. In order to investigate the effect of inhibitingGFAP gene expression on normal, reactive astrocytes and on glial scar formation, the efficiency of the recombinant antisenseGFAP retrovirus (PLBskG) on the growth, cell cycle, morphology andGFAP gene expression of astrocytesin vitro and on the formation of glial scarsin vivo has been studied by cell growth curves, flow cytometry, immunocytochemistry,in situ hybridization, RT-PCR and Southern blot. The results confirm the recombinant retrovirus (PLBskG) produced growth suppression and G1 arrest of the normal and injured astrocytes. The infected cells become round or ellipoid. The cell processes become fine or retracted. The intensity of staining ofGFAP is reduced. Expression ofGFAP mRNA is down regulated. However, in the control experiment, no obvious effects on the morphology or synthesis ofGFAP on cultured normal and scratched astrocytes infected by primary retrovirus vector (PLXSN) have been observed. The supernatant of PLBskG has been injected into an injured site by microinjectionin vivo. The number and process lengths of GFAP positive cells are obviously reduced around the injured site. The formation of the glial scar is inhibited, showing that the recombinant antisenseGFAP retrovirus can effectively inhibit the growth andGFAP expression of normal and injured astrocytesin vitro and the formation of glial scarin vivo. It is suggested thatGFAP plays an important role in glial scar formation.     

Induction of embryonic stem cells to hematopoietic cellsin vitro

In order to get hematopoietic cells from embryonic stem (ES) cells and to study development mechanisms of hematopoietic cells, the method of inducing embryonic stem cells to hematopoietic cells was explored by differenciating mouse ES cells and human embryonic cells in three stages. The differentiated cells were identified by flow cytometry, immunohistochemistry and Wright’s staining. The results showed that embryoid bodies (EBs) could form when ES cells were cultured in the medium with 2-mercaptoethanol (2-ME). However, cytokines, such as stem cell factor (SCF), thrombopoietin (TPO), interleukin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO) and granular colony stimulating factor (G-CSF), were not helpful for forming EBs. SCF, TPO and embryonic cell conditional medium were useful for the differentiation of mouse EBs to hematopoietic progenitors. Eighty-six percent of these cells were CD34⁺ after 6-d culture. Hematopoietic progenitors differentiated to B lymphocytes when they were cocultured with primary bone marrow stroma cells in the DMEM medium with SCF and IL-6. 14 d later, most of the cells were CD34^－CD38⁺. Wright’s staining and immunohistochemistry showed that 80% of these cells were plasma-like morphologically and immunoglubolin positive. The study of hematopoietic cells from human embryonic cells showed that human embryonic cell differentiation was very similar to that of mouse ES cells. They could form EBs in the first stage and the CD34 positive cells account for about 48.5% in the second stage.     

菊苣酸在 HepG2细胞中对SOSC3表达的调节作用

探讨菊苣酸(Chicoric acid,CRA)在人肝细胞系HepG2细胞中对细胞因子信号转导抑制分子3(Suppressor of cyto-kine signaling 3,SOCS3)表达的影响,用剂量为0、5和50μg.mL-1 CRA分别处理HepG2细胞24h后,经RT-PCR、Real-time PCR检测SOCS3基因的mRNA表达情况,再以上述不同剂量CRA分别处理细胞24h以及50μg.mL-1CRA分别处理HepG2细胞0、6、12、18和24h后,用Western blot法检测SOCS3基因的表达情况。研究结果显示CRA作用于HepG2细胞后,SOCS3基因的mRNA和蛋白表达水平随着CRA剂量增加而显著下降(p<0.01),且呈现一定的剂量依赖性;随着处理时间的增加,SOCS3蛋白表达水平下降更加明显,说明在翻译水平CRA不仅呈剂量依赖性,还呈时间依赖性下调SOCS3蛋白的表达。这些结果提示CRA可抑制SOCS3蛋白在HepG2细胞中的表达。     

脉象信号的特征提取与识别方法

中医脉象信号的研究在中医诊断中具有重要的意义。为了探索由中医脉象信号识别海洛因吸毒者的有效方法,研究了中医脉象信号特征提取的倒双谱与三阶倒谱熵算法。在简洁而准确地论述算法的基础上,估计了20例海洛因吸毒者与20例健康正常人脉象信号的倒双谱的对角切片分量。在大量实验结果的基础上,选取对角切片在m=n=1处的抽样幅值、在特定区域内抽样幅值的三阶倒谱熵作为每例脉搏波信号的2个特征参数,并构成特征向量。以平方马氏距离为准则设计了分类器,该分类器对40个特征向量的准确识别率为87.5%。研究结果表明,提出的特征提取与分类器设计方法对海洛因吸毒者脉象信号的识别具有一定的意义。     

手指自主按键运动中脑磁图信号的相干性分析

为了获取手指运动过程中不同脑功能区之间的联系,以及这种功能性联系在时频域和空间的变化,记录了与手指运动相关的脑磁图信号,然后对其进行相干性分析,并计算了不同位置信号之间的相干性系数。通过时频分析进一步探讨了在α(5～15Hz)、β(16～25Hz)、lowγ(30～45Hz)3个频带的不同皮层区联系随时间的变化关系。结果表明:α、β、lowγ 3个频带与所选参考信号相干性呈现出位置大致相同,相干强度和相干范围均从α到lowγ依次递减,相干性系数随时间而变化,进而推论出相干性的变化表明对侧运动皮层存在不同的神经模式,而且这些神经模式也是随时间变化的,由此反映出不同功能区的联系在时频域的变化。     

一类非线性感染率病毒动力学模型分析

构建了一类具有非线性感染率的病毒动力学模型并分析了它的全局动力学性态.结果表明引入的非线性感染率不会影响病毒感染的最终结局,是一类无害非线性感染率.     

线性对称三弹簧振子振动的数值研究

从线性对称三弹簧振子系统振动的非线性微分方程出发进行数值求解,在不同系统参数和初始条件下,给出振子的振动图像．研究几种情况下振动数值周期的变化规律,得到了较好的结果．     

NHE3 phosphorylation via PKCη marks the polarity and orientation of directionally migrating cells

Endogenous electric fields (EF) may provide an overriding cue for directional cell migration during wound closure. Perceiving a constant direction requires active sodium-hydrogen exchanger (pNHE3) at the leading edge of HEK 293 cells but its activation mechanism is not yet fully understood. Because protein kinase C (PKC) is required in electrotaxis, we asked whether NHE3 is activated by PKC during wound healing. Using pharmacological (pseudosubstrate and edelfosine) inhibition, we showed that inhibition of PKCη isoform impairs directional cell migration in HEK 293 cells in the presence of a persistent directional cue (0.25–0.3 V/mm of EF for 2 h). Further, we found that pNHE3 forms complexes with both PKCη and ?-tubulin, suggesting that these molecules may regulate the microtubule-organizing center. In addition, cellular pNHE3 content was reduced significantly when PKCη was inhibited during directional cell migration. Taken together, these data suggest that PKCη-dependent phosphorylation of NHE3 and the formation of pNHE3/PKCη/?-tubulin complexes at the leading edge of the cell are required for directional cell migration in an EF.     

高扇入与/或逻辑的设计与实现

针对高性能浮点乘加部件中的应用需求,全定制设计了高性能52位或门和108位与门.设计中使用HSPICE工具进行电路模拟,模拟时使用CSM 0.13 μm最慢工艺参数,电源电压为1.2 V,温度为25℃.根据各种实现方式的电路特性,使用相应的理论上电路最大延时的输入激励进行模拟,输入激励的频率为1.25 GHZ,斜率为输入激励周期的10%.输出延时是每个输入周期中输入电压的50%到输出电压的50%之间的时间,最大延时是所有输入数据中的最长延时.根据不同的逻辑类型,设计实现了5种52位或门;选取了静态互补CMOS逻辑、np-CMOS逻辑两种直接实现的108位与门,并选取了多米诺逻辑间接实现方式.对比模拟结果可以得到,全定制设计实现的52位或门和108位与门在速度、功耗和面积方面都具有较优的综合性能.