Preparation and in vitro studies of microencapsulated cells releasing human tissue inhibitor of metalloproteinase-2

Objective: To prepare microencapsulated cells releasing human tissue inhibitor of metalloproteinase-2 (TIMP-2), and investigate their biological characteristics in vitro. Methods: Chinese hamster ovary (CHO) cells were stably transfected with a human TIMP-2 expression vector, encapsulated in barium alginate microcapsules and cultured in vitro. Morphological appearance of the microcapsules was observed under a light microscope. Cell viability was assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Enzyme linked immunosorbent assay (ELISA) and reverse zymography were used to confirm the release of biologically active TIMP-2 from the microcapsules. Cryopreservation study of the microencapsulated cells was carried out using dimethyl sulfoxide (DMSO) as preservative agent. Results: The microcapsules appeared like a sphere with diameter of 300–600 μm. The surface of the capsule wall was clearly smooth. The microencapsulated cells survived well and kept proliferating over the 6 weeks observed. No significant difference in TIMP-2 secretion was found between encapsulated and unencapsulated cells. Reverse zymography confirmed the bioactivity of MMP (matrix metalloproteinase) inhibition of TIMP-2. The cryopreservation process did not damage the microcapsule morphology nor the viability of the cells inside. Conclusion: Microencapsulated engineered CHO cells survive at least 6 weeks after preparation in vitro, and secrete bioactive TIMP-2 freely from the microcapsules.     

无脑儿心脏的组织学观察与比较

目的:探讨无脑儿与正常胎儿心脏结构的差异,为畸形胎儿的心脏发育研究提供形态学方面的资料。方法:用H.E染色,通过光镜观察无脑儿及正常胎儿的心脏结构。结果:无脑儿心脏的蒲肯野细胞数量明显低于同龄正常胎儿。结论:无脑儿神经系统发育异常影响其心脏内蒲肯野细胞的发育。     

试论非线性编辑系统的性能

非线性编辑系统是近年来比较流行的一种电视编辑系统 ,采用该系统编辑电视节目 ,电视信号基本没有损失。非线性编辑系统主要由计算机和编辑软件及外部设备来完成编辑工作的。作为电视工作者必须要掌握和了解非线性编辑系统的基本性能和特点 ,以及在电视节目制作中的实际应用     

COMPUTER SIMULATION FOR ELECTRICALLY DRIVEN MOTION OF FLUID

In this paper,an equation system of electrohydrodynamics(EHD)based onthe fluid motion equations is discussed.Emphasis is put on the effects of electrical forceand surface tension upon the fluid motion.The Marker and Cell method is used to set up acomputational simulation program of electrically driven motion of fluid.With the help ofthe program,a cylindrical fluid under the influences of electrical field and surface tensionhas been calculated.The result is in good agreement with the experimental observation.     

Review:DNA-damage response network at the crossroads of cell-cycle checkpoints, cellular senescence and apoptosis

Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senes- cence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving “sensor” proteins that sense the damage, and transmit signals to “transducer” proteins, which, in turn, convey the signals to numerous “effector” proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.     

与上网相关的注册表安全技术

如今，互连网与人们的生活息息相关，但上网产生问题不少，特别是某些网站对注册表的修改让许多用户无所适从，烦恼不已，因此，懂得相关注册表的知识就显得尤为重要。     

A novel cell search scheme for OFDM cellular systems

INTRODUCTION Owing to its inherent ability to combat the multi-path fading channel, the modulation technology of orthogonal frequency division multiplexing (OFDM) has been widely used in many high-rate data transmissions such as digital video broadcasting (DVB-T), wireless local area network (IEEE 802.11a) and broadband wireless access (IEEE 802.16e). Re-cently, it is accepted as the most promising candidate for E-UTRA downlink (3GPP TSG-RAN-1, 2006a), which is a super 3G cell…     

Say Goodbye…Let's Roll: The Social Dynamics of Wireless Networks on September 11

This article describes the use of wireless telecommunication media within the different locations directly affected by the hijackings on September 11. Comparisons across these different contexts provides an empirical anchor to more general themes concerning the social dynamics of wireless in the unfolding events of this day. An indication is given of how the important social role of wireless phones in this crisis could redefine public views on wireless media and thereby shape policy and regulation in the years ahead.     

浅议教育类期刊编辑的市场意识

目前，教育类期刊市场面临着历史性的发展机遇，同时市场的竞争也日益激烈，要求编辑树立市场意识，从编辑的角度参与期刊的市场竞争。教育类期刊编辑的市场意识主要包括读意识、竞争意识、创新意识、经营意识和法律意识。     

Toxic effects of Litsea elliptica Blume essential oil on red blood cells of Sprague-Dawley rats

Litsea elliptica Blume leaves have been traditionally used as medicinal herbs because of its antimutagenicity, che-mopreventative and insecticidal properties. In this study, the toxic effects of L. elliptica essential oil against Sprague-Dawley rat's red blood cells (RBCs) were evaluated. L. elliptica essential oil was given by oral gavage 5 times per week for 3 treated groups in the doses of 125, 250, and 500 mg/(kg body weight), respectively, and the control group received distilled water. Full blood count, RBC osmotic fragility, RBC morphological changes, and RBC membrane lipid were analyzed 28 d after the treatment. Although L. elliptica essential oil administration had significantly different effects on hemoglobin (Hb), mean cell hemoglobin concentration (MCHC), mean cell volume (MCV), and mean cell hemoglobin (MCH) in the experimental groups as compared to the control group (P<0.05), the values were still within the normal range. L. elliptica induced morphological changes of RBC into the form of echinoeyte. The percentage of echinocyte increased significantly among the treated groups in a dose-response manner (P<0.001). The concentrations of RBC membrane phospholipids and cholesterol of all treated groups were significantly lower than those of control group (P<0.001). However, the RBC membrane osmotic fragility and total proteins of RBC membrane findings did not differ significantly between control and treated groups (P>0.05). It is concluded that structural changes in the RBC membrane due to L. elliptica essential oil administration did not cause severe membrane damage.