基于能源细胞-组织架构的区域能源网需求响应研究挑战与展望

在能源互联网趋势下,区域能源网需求响应的研究对消纳可再生能源、实现供需平衡、增强电网灵活性与可靠性具有重要意义。围绕区域能源系统需求侧规划与运行优化这一主题,基于能源细胞-组织架构,从能源细胞内部、细胞间、细胞-组织间3个层次切入,具体分析了以微网、多微网为代表的需求侧负荷用户建模、能源管理规划、运行优化方式、信息能源耦合互动交流、电力市场配置等研究现状。然后结合数据处理和智能决策前沿技术,从预测、规划决策、市场机制三方面对区域能源系统需求响应的关键技术进行归纳。最后从实施规模、社会、经济、信息方面对区域能源网需求响应发展进行了展望。

关于细胞-组织视角的能源互联网分布式自治系统形态特征的讨论

以能源互联网为代表的能源工业核心方案促进了多种能源和电力的互动,极大地改变了多种复杂网络的结构层次和耦合模式。在此背景下,比较了信息互联网和能源互联网的特点,总结了能源互联网关键技术和研究难点,并提出能源路由器等物理设备在SoS(system of systems)概念下的全新意义。然后,在总结了目前能源互联网的几种架构和运行形态的基础上,提出细胞-组织(cell-tissue)视角下能源互联网的形态特征和描述方法,并在信息网络安全、运行状态评估和网络建模技术方法等诸多核心问题上,展望能源互联网现实应用的研究重点。

细胞-组织认知下的主动配电系统双层多目标控制策略

近年来,大规模的可再生能源已被广泛集成到电力系统中,配电系统的主导形式也从传统配电网逐渐转变到微网集群。由于风、光等可再生能源具有不确定性,为了优化可再生资源在电力系统中的整合效果,并考虑对微网集群的智能化管理以改善配网运行水平,基于"细胞-组织"结构提出了一种新型双层多目标动态能量管理策略;然后在主动配电系统中将主动配电网和微网集群之间的关系进行了分类,并提出能量博弈矩阵和双层多目标控制策略对主动配电网和微网集群的能量管理进行描述和实现;最后采用分层-带精英策略的快速非支配排序混合遗传算法(hierarchical genetic algorithm-NSGA-Ⅱ,HGA-NSGA-Ⅱ)求解能量管理问题,并通过对基于多微网的混合IEEE-33电力系统的仿真分析,验证了所提控制策略在功耗水平、能源利用率和仿真运算时间等方面上的优势。

绵羊卵丘-卵母细胞复合体石蜡切片技术的改良

【目的】在绵羊有腔卵泡发育过程中,多层卵丘细胞紧密包绕着卵母细胞形成卵丘-卵母细胞复合体(cumulus-oocyte complex,COCs)特殊结构,存在于卵泡腔内。卵泡成熟后,绵羊COC从卵泡内排出,进入输卵管,等待受精。现有的卵丘-卵母细胞复合体蛋白鉴定技术,或者将包含各级卵泡的卵巢组织直接进行切片处理,或者将COCs从卵泡内分离,在完整卵丘-卵母细胞复合体水平上进行免疫染色。但这两种方法在检测绵羊有腔卵泡COCs中目的蛋白表达时,存在显著缺陷。研究旨在对常规石蜡组织切片技术进行改进,以期满足绵羊COCs蛋白鉴定需求。【方法】首先采用抽吸法从绵羊有腔卵泡内获得COCs,以石蜡包埋方式人为构建了一种可以进行切片处理的"包含多枚绵羊卵丘-卵母细胞复合体的仿组织结构"。然后以该特殊结构与健康绵羊卵巢组织为研究对象,分别采用改良与传统的石蜡组织免疫化学技术流程,检测了目的蛋白,尿激酶型纤溶酶原激活剂(urokinase-type plasminogen activator,uPA)与其受体(urokinase-type plasminogen activator recepter,uPAR),在绵羊COCs中的表达情况,比较了两种技术的免疫染色效果与染色流程差异。【结果】将所构建的绵羊COCs仿组织结构与正常绵羊卵泡组织,进行石蜡组织切片处理,经切片、贴片与脱蜡等步骤,分别形成了散在分布于载玻片上的COCs薄片与包含卵泡的卵巢组织薄层(厚度5μm)。经间接免疫染色处理后,结果显示:①目的蛋白在两种结构COCs中的表达是一致的,即uPAR在绵羊卵丘与卵母细胞上都有表达,而uPA只存在于绵羊卵丘细胞中;②在绵羊COCs薄片结构中,COCs整体形态完好,卵母细胞与外围卵丘细胞层次清晰,蛋白定位清楚,染色效果良好;在卵巢薄层结构中,绵羊卵泡内壁颗粒细胞与COCs等形态结构相对完整,卵母细胞蛋白定位清楚,但是卵丘细胞层次与蛋白表达较不清晰;③与绵羊卵巢组织石蜡切片技术相比较,绵羊COCs仿组织结构石蜡切片技术,在固定、脱水、透明、浸蜡以及脱蜡等步骤的处理时间都大大缩短,例如固定处理由24h缩短为2h;由逐级脱水的10h缩短为两级脱水的1h;透明由30min缩短为10min;软蜡与硬腊浸入由原来的6h缩短为1h;由逐级脱蜡的25min缩短为两级脱蜡的10min等。【结论】改进后的COCs仿组织石蜡切片染色技术,显示更优质的免疫定位与染色效果,不仅具有COCs获得率高、卵母与卵丘细胞形态层次清晰等优点,而且显著缩短了操作时间,简化了操作流程。该技术在保留COCs结构完整的基础上,有效检测了目的蛋白在绵羊卵丘-卵母细胞复合体中的表达模式,对于探明绵羊卵泡发育与卵母细胞成熟机制,具有重要意义。

还氧化酶-2在宫颈鳞状细胞癌中的表达研究

目的探讨还氧化酶-2(COX-2)在宫颈鳞状细胞癌中的表达及临床意义。方法采用免疫组化的方法对56例子宫颈鳞状细胞癌组织进行COX-2检测。结果肿瘤细胞中COX-2与肿瘤的分级分期呈高度正相关(P<0.01)。结论COX-2表达在宫颈鳞状细胞癌中对肿瘤的分级分期起到重要的作用。

即插即用能量组织日前负荷概率预测方法

随着对利用新能源的迫切需求,分布式能源将以“能量细胞”的形式分布在用户侧,并具有即插即用的特点。受到利益的驱动或稳定性的要求,“能量细胞”将组成形态各异的“能量组织”,而新形成的“能量组织”则存在历史数据较少的问题。针对“能量组织”中小样本日前负荷概率预测问题,提出基于pinball损失函数的深度长短时记忆(long short-term memory,LSTM)网络概率预测方法。为解决小样本下深度LSTM网络的过拟合问题,采用自底向上的层次聚类方法进行数据增强,并针对各个分位点进行并行预测。实验结果表明,所提方法能够获得较高的可靠性以及锐度较好的置信区间,可以为日前调度提供合理依据。

Reproduction of the Three-line Genic Male Sterile Line Parent Mian 7MB-1 （Brasscia Napus L.） and Seed Production of F1 Based on Somatic Tissue Culture

[Objective] The aim was to study the reproduction of the three-line genic male sterile （GMS） lineparent Mian7MB-1 （B. NapusL.） and the seed production of F1 through somatic tissue culture. [Methed] Through hybridization, a new breeding material Mian 7MB-1 in three-line genic temporary maintainer line propagated by tissue culture was used to improve the sterile plant rate of rapeseed in dual-purpose recessive GMS line, such as Mian 7AB type, S45AB type, and etc. And then the variety comparative test was performed. [Result] In order to avoid some fertility restoration phenomena occurring during the process of self-reproduction, Mian 7AB was propagated in bulk with somatic tissue culture of temporary maintainer line plant stem. The propagated temporary maintainer line seedlings were applied to the breeding and seed production of net room male sterile line parent, promoting the sterile plant rate of the male sterile line parent to 91.7% -93.5%. The male sterile line parents per hectare were enough for the seed production of hybrid F1 in 7 500 -15 000 hm^2. [ Conclusion ] Compared with the original dual-purpose GMS line, the seed production ultilizing male sterile line with high sterile plant rate greatly reduced the labor, significantly improved the seed yield, ensuring the seed quality and forming a perfect breeding and seed production system.

Negative correlation of Nogo-A with the malignancy of oligodendroglial tumor

Objective Nogo-A is an axon regeneration inhibitor, and its function in central nervous system （CNS） is still unknown. The present study is to explore the relationship between the expression of Nogo-A and the malignancy of oligodendroglial tumors in patients. Methods Tumor tissue samples with different malignancy grade were obtained from the hospitals. The samples used for detection had been diagnosed as oligodendroglial tumors （oligodendroglioma or anaplastic oligodendroglioma）. The expression of Nogo-A was detected by irmnunohistochemistry and western-blot analysis. The correlation test between the Nogo-A expression and the morphological changes （the percentages of atypical cells and mitotic cells in the tumors） related to the malignancy of tumor tissues was performed. Results There was significant negative correlation between the Nogo-A expression and the morphological change of tumor tissues according to immunohistochemistry. Western-blot analysis also indicated that the gray value of Nogo-A protein band in the oligo- dendroglioma group was significantly higher than that in the anaplastic oligodendroglioma group. Conclusion Nogo-A expression was negatively correlated with the malignancy grade of oligodendroglial tumors.

Role of Tissue Factor Pathway Inhibitor-2 in Ovarian Tumor Migration and Invasion

Objective: To elucidate the relation between human tissue factor pathwayinhibitor-2 (TFPI-2) expression and ovarian tumor migration and invasion. Methods: Human TFPI-2expression vector pBos-Cite-neo/TFPI-2 was transfected into ovarian tumor cells line A2780- Afterthe transfected cells were selected by G418, transfected and nontransfected cells were screened forTFPI-2 mRNA and protein by reverse transcription-polymerase chain reaction and Western blotanalysis, respectively. The number of transfected or nontransfected cells passing through membraneof Boyden chamber was counted as the basis assessing tumor cells migratory and invasive behaviors.Results: Expression of mRNA and protein of TFPI-2 was detectable in transfected cells. In invasionassay, the number of TFPI-2-expressing cells to traverse a Matrigel-coated membrane was obviouslydecreased compared with that of nonexpressing cells (59.3±6.5 vs 109.7±5.5, P 【 0.01); While inmigration assay, no significant difference through a noncoated membrane was observed amongtransfected and nontransfected cells (114.7±8.6 vs 127.3±7.1, P 】 0.05). Conclusion: Expression ofTFPI-2 may strongly inhibit the invasive ability of ovarian tumor cells in vitro, but has no effecton the migratory ability which provides an experimental basis for genotherapy of human ovariantumor.

NaOH消蚀法制备脱细胞真皮基质修补腹壁疝

背景:与其他疝修补材料相比,脱细胞真皮基质具有易血管化、抗感染、从而可用替代传统补片用于感染腹壁缺损重建等特点。目的:观察NaOH消蚀法制备的脱细胞真皮基质作为修补材料应用于腹疝的应用价值。方法:以全厚猪皮制成脱细胞真皮基质,45只SD雄性大鼠制备腹壁疝模型,随机数字表法分为腹壁疝组:直接缝合皮肤,Marlex网组和脱细胞真皮基质组:分别应用大小为3.5cm×4.0cm的Marlex网和脱细胞真皮基质缝合皮肤;观察修复后1周时有无腹壁疝发生,脱细胞真皮基质组修复后1,2,3,5,10周分别取材,其中每周各组取4只用于苏木精-伊红染色,光镜观察。修复后第5周Marlex网组和脱细胞真皮基质组各取6只用于抗张力试验。结果与结论:术后1周脱细胞真皮基质组与Marlex网组腹壁疝发生率均显著低于腹壁疝组(P<0.001)。脱细胞真皮基质的胶原纤维无明显变化,即有少量成纤维细胞植入,术后2周可见新生血管,术后5周脱细胞真皮基质内部血管密度基本稳定。将单独脱细胞真皮基质片与Marlex网行抗张力试验,Marlex网的抗张力显著高于脱细胞真皮基质(P<0.001)。但植入体内5周后,脱细胞真皮基质筋膜组织的抗张力高于Marlex-筋膜组织(P<0.05)。提示复合消蚀制备的脱细胞真皮基质可以作为良好的疝修补材料。

何杰金氏病的免疫组织化学研究

对71例福尔马林固定、石蜡包埋的活检淋巴组织用ABC免疫组织化学法进行12种凝集素,LeuM_1,α_1-AT,α_1-ACT及Lys标记,发现PSA,ConA,LCA,RCA,PHA,PNA,α_1-AT,α_1-ACT及Lys对HD肿瘤细胞及H-M胞质阳性,并且两者胞质反应形式一致。这6种凝集素在H-M胞质可形成GB,形成GB的H-M称为G细胞。凝集素及α_1-AT,α_1-ACT及Lys标记结果支持HD瘤细胞来源于H-M.LeuM_1及PNA只对HD瘤细胞阳性,并标记少数H-M,对其余成分阴性,故LeuM_1及PNA对HD的诊断、鉴别诊断有意义。HD恶性程度越高,则G细胞越多。

Intermittent hypoxia attenuates ischemia/reperfusion induced apoptosis in cardiac myocytes via regulating Bcl-2/Bax expression

Intermittent hypoxia has been shown to provide myocardial protection against ishemia/reperfusion-induced injury.Cardiac myocyte loss through apoptosis has been reported in ischemia/reperfusion injury. Our aim was to investigate whether intermittent hypoxia could attenuate ischemia/reperfusion-induced apoptosis in cardiac myocytes and its potential mechanisms. Adult male Sprague-Dawley rats were exposed to hypoxia simulated 5000 m in a hypobaric chamber for 6 h/day, lasting 42 days. Normoxia group rats were kept under normoxic conditions. Isolated perfused hearts from both groups were subjected to 30 min of global ischemia followed by 60 min reperfusion.Incidence of apoptosis in cardiac myocytes was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and DNA agarose gel electrophoresis. Expressions of apoptosis related proteins,Bax and Bcl-2, in cytosolic and membrane fraction were detected by Western Blotting. After ischemia/reperfusion,enhanced recovery of cardiac function was observed in intermittent hypoxia hearts compared with normoxia group.Ischemia/reperfusion-induced apoptosis, as evidenced by TUNEL-positive nuclei and DNA fragmentation, was significantly reduced in intermittent hypoxia group compared with normoxia group. After ischemia/reperfusion,expression of Bax in both cytosolic and membrane fractions was decreased in intermittent hypoxia hearts compared with normoxia group. Although ischemia/reperfusion did not induce changes in the level of Bcl-2 expression in cytosolic fraction between intermittent hypoxia and normoxia groups, the expression of Bcl-2 in membrane fraction was upregulated in intermittent hypoxia group compared with normoxia group. These results indicated that the cardioprotection of intermittent hypoxia against ischemia/reperfusion injury appears to be in part due to reduce myocardial apoptosis. Intermittent hypoxia attenuated ischemia/reperfusion-induced apoptosis via increasing the ratio of Bcl-2/Bax, especially in membrane fraction.

Reduced expression of E-cadherin/catenin complex in hepatocellular carcinomas

AIM： TO examine the immunoreactivity of E-cadherin and four subtypes of catenin family in human hepatocellular carcinomas （HCCs） and to investigate the correlation between expression of E-cadherin/ catenin complex and clinicopathologic parameters of HCC patients. METHODS： An immunohistochemical study for E-cadherin and catenins was performed on 97 formalin-fixed, paraffin-embedded specimens of HCC. RESULTS： Reduced expression of E-cadherin, ^-, 13-, y-catenin and p120 was observed in 69%, 76%, 63%, 71% and 73%, respectively. Both expressions of E-cadherin and catenin components were significantly correlated with tumor grade （P = 0.000）. It showed significant difference between expression of catenin members and tumor stage （P = 0.003, P = 0.017, P = 0.007 and P = 0.000, respectively）. The reduced expression of E-cadherin in HCCs was significantly correlated with intrahepatic metastasis （IM） and capsular invasion （P = 0.008, P = 0.03, respectively）. A close correlation was also observed between the expression of catenins and the tumor size （P = 0.002, P = 0.034, P = 0.016 and P = 0.000, respectively）. In addition, the expression of each catenin was found correlated with IM （P = 0.012, P = 0.049, P =0.026 and P = 0.014, respectively）. No statistically significant difference was observed between the expression level of E-cadherin/catenin complex and lymph node permission, vascular invasion and satellite nodules. Interestingly, only expression of p120 showed correlation with AFP value （P = 0.035）. The expression of E-cadherin was consistent with α-, β-, γ-catenin and p120 expression （P = 0.000）. Finally, the abnormal expression of E-cadherin/catenin complex was significantly associated with patients＇ survival （P = 0.0253, P = 0.0052, P = 0.003, P = 0.0105 and P = 0.0016, respectively）. Nevertheless, no component of E-cadherin/catenin complex was the independent prognostic factor of HCC patients. CONCLUSION： Down-regulated expressions of E-cadherin, catenins and p120 occur frequently in HCCs and contribute to the progression and development of tumor. It may be more exact and valuable to detect the co-expression of E-cadherin/catenin complex than to explore one of them in predicting tumor invasion, metastasis and patient＇s survival.

Interleukin-1 beta up-regulates tissue inhibitor of matrix metalloproteinase-1 mRNA and phosphorylation of c-jun N-terminal kinase and p38 in hepatic stellate cells

AIM： To study the relationship between interleukin-lbeta （IL-1β） up-regulating tissue inhibitor of matrix metalloproteinase-1 （TIMMP-1） mRNA expression and phosphorylation of both c-jun N-terminal kinase （INK） and p38 in rat heffatic stellate cells （HSC）. METHODS： RT-PCR was performed to measure the expression of TIMMP-1 mRNA in rat HSC. Western blot was performed to measure IL-1β-induced JNK and p38 activities in rat HSC. RESULTS： TIMMP-1 mRNA expression （1.191± 0.079） was much higher after treatment with IL-1β （10 ng/mL） for 24 h than in control group （0.545±0.091） （P〈0.01）. IL-1β activated INK and p38 in a time-dependent manner. After stimulation with IL-1β for 0, 5, 15, 30, 60 and 120 min, the INK activity was 0.982±0.299, 1.501±0.720, 2.133±0.882, 3.360±0.452, 2.181±0.789, and 1.385 ± 0.368, respectively. There was a significant difference in JNK activity at 15 min （P〈 0.01）, 30 min （P〈 0.01） and 60 min （P〈0.01） in comparison to that at 0 min. The p38 activity was 1.061±0.310, 2.050±0.863, 2.380±0.573, 2.973±0.953, 2.421±0.793, and 1.755 ± 0.433 at the 6 time points （0, 5, 15, 30, 60 and 120 min） respectively. There was a significant difference in p38 activity at 5 min （P〈0.05）, 15 min （P〈0.01）, 30 min （P〈0.01） and 60 min （P〈0.01） compared to that at 0 min. TIMMP-1 mRNA expression trended to decrease in 3 groups pretreated with different concentrations of SP600125 （10 μmol/L, 1.022±0.113; 20 μmol/L, 0.869±0.070; 40 μmol/L, 0.666±0.123）. Their decreases were all significant （P〈0.05, P〈0.01, P〈0.01） in comparison to control group （without SP600125 treatment, 1.163±0.107）. In the other 3 groups pretreated with different concentrations of SB203580 （10 μmol/L, 1.507±0.099; 20 μmol/L, 1.698±0.107; 40 μmol/L, 1.857±0.054）, the expression of TIMMP-1 mRNA increased. Their levels were higher than those in the control group （without SB203580 treatment, 1.027 ± 0.061） with a significant statistical significance （P〈 0.01）. CONCLUSION： IL-1β has a direct action on hepatic fibrosis by up-regulating TIMMP-1 mRNA expression in ratessionin in rate HSC.JNK and p38 mitogen-activated protein kinases （MAPKs） are involved in IL-1β-induced TIMMP-1 gene expression, and play a distinct role in this process, indicating that p38 and .INK pathways cooperatively mediate TIMP-1 mRNA expression in rat HSC.

Changes of CD8+CD28-T regulatory cells in rat model of colitis induced by 2,4-dinitrofluorobenzene

AIM:To determine the changes of CD8+ T subsets especially CD8+CD28-T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB). METHODS:The rat model of experimental colitis was induced by enema with DNFB.Ten days later,colonic intraepithelial and splenic lymphooltes were isolated from colitis animals (n=16) and controls (n=8).The proportion of CD8+ T cells,CD8+CD28+ T cells and CD8+CD28-T regulatory cells were determined by flow cytometry. RESULTS:The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea,weight loss and colonic histopathology.The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen:34.6±7.24 % vs 33.5±9.41%, colon:14.0±8.93 % vs 18.0±4.06 %,P>0.05).But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen:11.3±2.26 % vs 5.64±1.01%, colon:6.50±5.37 % vs 1.07±0.65 %,P<0.05).In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen:23.3±6.14 % vs 27.8±9.70 %,P=0.06; colon:7.52±4.18 % vs 16.9±4.07 %,P<0.05).The proportion of CD8+CD28-T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen:33.3±5.49 % vs 18.4±7.26 %, colon:46.0±14.3 % vs6.10±3.72 %,P<0.005). CONCLUSION:Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility.The proportion of CD8+CD28-T regulatory cells in rats with experimental colitis is increased,which may be associated with the pathogenesis of colitis.

Promoter hypomethylation and reactivation of MAGE-A1 and MAGE-A3 genes in colorectal cancer cell lines and cancer tissues

AIM： To verify the expression and methylation status of the MAGE-A1 and MAGE-A3 genes in colorectal cancer tissues and cancer cell lines. METHODS： We evaluated promoter demethylation status of the MAGE-A1 and MAGE-A3 genes by RT-PCR analysis and methylation-specific PCR （MS-PCR）, as well as sequencing analysis, after sodium bisulfite modification in 32 colorectal cancer cell lines and 87 cancer tissues. RESULTS： Of the 32 cell lines, MAGE-A1 and MAGE-A3 expressions were observed in 59% and 66%, respectively. Subsequent to sodium bisulfite modification and MSPCR analysis, the promoter hypomethylation of MAGE-A1 and MAGE-A3 was confirmed in both at 81% each. Promoter hypomethylation of MAGE-A1 and MAGE-A3 in colorectal cancer tissues was observed in 43% and 77%, respectively. Hypomethylation of MAGE-A1 and MAGE-A3 genes in corresponding normal tissues were observed in 2% and 6%, respectively. CONCLUSION： The promoter hypomethylation of MAGE genes up-regulates its expression in colorectal carcinomas as well as in gastric cancers and might play a significant role in the development and progression of human colorectal carcinomas.

Expression of γ-synuclein in colorectal cancer tissues and its role on colorectal cancer cell line HCT116

AIM: To investigate the expression pattern of γ-synuclein in colorectal cancer (CRC) tissues, and to study the effects of γ-synuclein on CRC cell line HCT116 biological features in vitro.METHODS: The expression pattern of γ-synuclein was determined in 54 CRC tissues and 30 tumor-matched nonneoplastic adjacent tissues (NNAT) 5 cm away from the tumor via real-time quantitative reverse transcription PCR (RT-PCR) and immunohistochemistry. The relationship between γ-synuclein protein expression and clinicopathological factors of CRC tissues was analyzed. Three small interfering RNA (siRNA) targeting γ-synuclein mRNA plasmids were constructed and transfected into the CRC cell line HCT116. The stable cell lines were selected with G-418 for 28 d, and the biological features of these cells were examined by cell growth curve, soft agar assay, and cell migration and invasion assays in vitro. RESULTS: The expression of γ-synuclein mRNA and protein was much higher in CRC tissue samples than in NNAT samples (P = 0.02, P = 0.036). There was a significant correlation between the γ-synuclein protein expression and clinical stage and lymph node involvement of CRC (P = 0.02, P = 0.033). In functional analysis we found that down-regulation of γ-synuclein expression in HCT116 cells could inhibit the growth, colony formation rate, and migration and invasion ability of HCT116 cells.CONCLUSION: Increased expression of γ-synuclein in CRC tissues and the biological effects of reduced γ-synuclein expression on HCT116 cells suggest that γ-synuclein may play a positive role in the progression of CRC.

Shp2-mediated molecular signaling in control of embryonic stem cell self-renewal and differentiation

A key issue to be addressed in stem cell biology is the molecular signaling mechanism controlling embryonic stem （ES） cell pluripotency. Stem cell properties are dictated by specific transcription factors and epigenetic processes such as DNA methylation and chromatin remodeling. Several cytokines/growth factors have been identified as critical ES cell regulators. However, there is a gap in our knowledge of the intracellular signaling pathways linking extracellular signals to transcriptional regulation in ES cells. This short review discusses the physiological role of Shp2, a cytoplasmic tyro- sine phosphatase, in the molecular switch governing ES cell self-renewal versus differentiation. Shp2 promotes ES cell differentiation, mainly through bi-directional modulation of Erk and Stat3 pathways. Deletion of Shp2 in mouse ES cells results in more efficient self-renewal. This observation provides the impetus to develop Shp2 inhibitors for maintenance and amplification of ES cells in culture.

Nuclear β-catenin expression as a prognostic factor in advanced colorectal carcinoma

AIM： To investigate the changing pattern of β-catenin expression and its prognostic value in advanced colorectal cancer （CRC）. METHODS： Archival tumor samples were analyzed for β-catenin using immunohistochemistry （IHC） in 95 patients with advanced CRC. RESULTS： Membranous β-catenin expression was found in the normal colorectal epithelium. Almost 100% of CRC cases showed membranous and cytoplasmic expression, and 55 （58%） cases showed nuclear expression. In univariate （Kaplan-Meier） survival analysis, only the nuclear index （NI） was a significant predictor of disease free survival （DFS） （P = 0.023; n = 35）, with a NI above the median associated with longer DFS （34.2 too） than those with a NI below the median （15.5 too） （P = 0.045, ANOVA）. The other indices were not significant predictors of DFS, and none of the three tested indices （for membranous, cytoplasmic, or nuclear expression） predicted diseasespecific survival （DSS）. However, when dichotomized as positive or negative nuclear expression, the former was a significant predictor of more favorable DFS （P = 0.041） and DSS （P = 0.046）. CONCLUSION： Nuclear β-catenin expression provides additional information in predicting patient outcome in advanced CRC.

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

Objective： To prepare microencapsulated cells releasing human tissue inhibitor ofmetalloproteinase-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 ~tm. 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.