溶血磷脂酸受体2调控胃癌细胞SGC-7901侵袭迁移以及增殖凋亡

为探讨LPA2是否可调节胃癌细胞SGC-7901的侵袭迁移及增殖凋亡,将LPA2 siRNA和pc DNA3.1-LPA2表达载体转染SGC-7901,转染后利用Western blotting检测LPA2、E-cadherin及Vimentin蛋白表达情况,Transwell实验检测细胞侵袭迁移能力,MTS实验检测细胞增殖,流式细胞仪检测凋亡情况。结果表明LPA2 siRNA对胃癌细胞SGC-7901敲除成功后,细胞内的E-cadherin表达增高,Vimentin表达降低;同时其侵袭、迁移和增殖能力降低,凋亡能力升高。细胞SGC-7901过表达LPA2后,细胞内的E-cadherin表达降低,Vimentin表达增加,其侵袭、迁移和增殖能力升高,凋亡能力降低。可见LPA2可调控胃癌细胞SGC-7901侵袭迁移以及增殖凋亡,为胃癌的治疗提供新的靶点。     

基于局部多项式逼近的图像去噪

为了兼得传统图像去噪算法的保边性与高效性的优点,本文根据图像空间相关性,设计了图像局部多项式逼近函数,理论上分析了局部逼近尺度,建立了局部多项式逼近去噪算法：首先对图像像素进行多项式拟合,构造局部多项式逼近函数;其次采用置信区间交集法则自适应选择局部多项式的逼近尺度;最后采用逼近算法对高斯噪声图像进行去噪.实验结果表明,本文算法继承了各向同性扩散的高效性和各向异性的保边性,同时弥补了各向异性扩散实时性较差的不足     

LPA法克隆嗜盐菌Halobacterium species xz515古紫质基因

Halobacterium species xz515是从中国西藏分离到的嗜盐菌，所含古紫质(古细菌视紫红质的简称命名为AR4)具有与其他已知菌视紫红质相反的质子释放和吸收的顺序而引起重视．连接反应介导的PCR扩增法(LPA)是一种克隆部分序列已知的基因的新型克隆方法．LPA法利用“酶切-连接-PCR”之组合，首先选定一组限制性内切酶，各自单独地酶切细菌总DNA样品，然后酶切产物分别与相应的寡聚核苷酸片段接头连接．连接液混合起来，作为扩增未知序列DNA的模板．通过这种方法，克隆到了包括完整AR4基因开放阅读框和0．4kb上游调控区域的总长度1．3kb的DNA片段．实验结果表明LPA法可以代替传统的构建基因组DNA文库的方法，可以快速有效地获得目标基因相关的序列．     

Autotaxin (NPP-2) in the brain: cell type-specific expression and regulation during development and after neurotrauma

Autotaxin is a secreted cell motility-stimulating exo-phosphodiesterase with lysophospholipase D activity that generates bioactive lysophosphatidic acid. Lysophosphatidic acid has been implicated in various neural cell functions such as neurite remodeling, demyelination, survival and inhibition of axon growth. Here, we report on the in vivo expression of autotaxin in the brain during development and following neurotrauma. We found that autotaxin is expressed in the proliferating subventricular and choroid plexus epithelium during embryonic development. After birth, autotaxin is mainly found in white matter areas in the central nervous system. In the adult brain, autotaxin is solely expressed in leptomeningeal cells and oligodendrocyte precursor cells. Following neurotrauma, autotaxin is strongly up-regulated in reactive astrocytes adjacent to the lesion. The present study revealed the cellular distribution of autotaxin in the developing and lesioned brain and implies a function of autotaxin in oligodendrocyte precursor cells and brain injuries. Received 18 September 2006; received after revision 30 October 2006; accepted 4 December 2006     

Lysophosphatidic acid up-regulates vascular endothelial growth factor-C and lymphatic marker expressions in human endothelial cells

Lysophosphatidic acid (LPA) is a low-molecular-weight lipid growth factor, which binds to G-protein-coupled receptors. Previous studies have shown that LPA enhances vascular endothelial growth factor-A (VEGF-A) expression in cancer cells and promotes angiogenesis process. However, the roles of LPA in lymphatic vessel formation and lymphangiogenesis have not been investigated. Here, we demonstrated that LPA up-regulated VEGF-C mRNA and protein expressions in human umbilical vein endothelial cells (HUVECs). Furthermore, the expression levels of lymphatic markers, including Prox-1, LYVE-1 and podoplanin, were enhanced in LPA-stimulated tube forming endothelial cells in vitro and in vivo. Moreover, we showed that pretreatment with MAZ51, a VEGFR-3 kinase inhibitor, and introduction of VEGFR-3 siRNA suppressed LPA-induced HUVEC tube formation and lymphatic marker expressions. These results demonstrated that LPA enhances expression of lymphatic markers through activating VEGF-C receptors in endothelial cells. This study provides basic information that LPA might be a target for therapeutics against lymphangiogenesis and tumor metastasis.     

The chatfield-prothero case study: Another look

The Chatfield-Prothero case study in time series, ‘Sales of a company X’, is analysed from a perspective different to that of the authors. More accurate forecasting performance for these data is obtained by adopting the following two tactics: (1) shifting from a problem in transformation of the original series to one of seasonality adjustment; (2) assuming a mixed seasonality type model in contrast to employing a multiplicative assumption.     

能量管理策略与员工工作结果关系的潜在剖面分析

基于努力-恢复模型和自我损耗理论，运用潜在剖面分析(LPA)，对企业中522名员工在工作中的能量管理策略类型进行了划分，并进一步对采用不同类型能量管理策略的员工在工作幸福感和工作绩效方面的异质性进行检验.研究表明，员工在工作中使用的能量管理策略包括回避能量使用型、工作能量使用型、休闲能量使用型和积极能量使用型4种类型.相比较而言，工作能量使用型和积极能量使用型员工的工作幸福感和工作绩效水平最高，且在结果上没有显著差异，休闲能量使用型次之，回避能量使用型最低.