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1.
研究从毛莨科唐松草属植物尖叶唐松草根部提取的新型醚键双生物碱-唐松草阿原碱对几种人体肿瘤细胞株的毒性作用。唐松草阿原碱以质量浓度从2.5μg/mL到100μg/mL作用于6种体外培养的肿瘤细胞株及2种正常细胞株,对其中4个肿瘤细胞株种表现了强烈的杀伤作用。IC50分别为:宫颈癌Hela37 μg/mL,肝癌LCC60μg/ml,胃癌MGC65μg/mL,非小细胞肺癌PLA-80182μg/mL,对2个正常细胞株的毒性分别为:肝细胞L-0265μg/mL,小鼠成纤维细胞NIH3T378μg/mL,而对另一株肝癌HepG2及乳腺癌细胞MCF-7无明显作用(IC50>100μg/mL)。  相似文献   

2.
硫酸甘油糖脂体外抑制肿瘤细胞增殖活性的研究   总被引:1,自引:0,他引:1  
目的:检测海藻硫酸甘油糖脂化合物(SQDG)的体外抗肿瘤活性,为寻找有效的抗癌新药提供理论依据.方法:采用MTT法检测SQDG对正常细胞的细胞毒性.在倒置显微镜下观察7种人类肿瘤细胞经SQDG处理72 h后的形态学变化,并用MTT法定量测定其生长抑制情况,同时应用流式细胞术检测细胞周期的改变.结果:SQDG对正常细胞Vero和MC的毒性都很小,其CC50值均大于500 μg/mL.它对人乳腺癌细胞MCF-7的生长抑制效果最明显,IC50值为69.1μg/mL,在质量浓度为125μg/mL时完全抑制MCF-7细胞生长.SQDG对H460、A549、HEp2和HeLa细胞也有一定的抑制效果,但对HepG2和A375细胞几乎没有影响.流式细胞术检测发现,SQDG能扰乱MCF-7的细胞周期,促使细胞凋亡或坏死,从而产生有效的生长抑制效果.但SQDC对H460和HepG2细胞周期的改变无统计学意义.结论:硫酸甘油糖脂SQDG对正常细胞无毒害,能选择性地有效抑制体外培养的乳腺癌细胞的生长,是一种有发展潜力的抗肿瘤药物.  相似文献   

3.
为研究苍耳子提取物对斑马鱼胚胎发育及运动行为的影响,取受精后12/24 h斑马鱼胚胎,将胚胎分别置于不同浓度苍耳子提取物溶液中,在作用不同时间后,显微镜下统计孵化率、死亡率和心率;取受精后120 h斑马鱼胚胎,用不同浓度苍耳子提取物处理60 min后,利用行为学分析系统统计各组斑马鱼在0~10、10~20、20~30 min内行为轨迹,基于游行距离与游行时间得到游行速度,并统计转圈值。结果表明,苍耳子提取物对受精后12 h斑马鱼胚胎的发育有毒性,使斑马鱼胚胎的孵化率降低,在提取物浓度大于15μg/mL时,孵化率低于40%;0.93μg/mL苍耳子提取物可提高24 h斑马鱼胚胎的心率(P≤0.01),当提取物浓度大于7.5μg/mL时,心率显著性降低(P≤0.01);在行为学分析中发现,当苍耳子提取物浓度大于3μg/mL时,游行速度与转圈均值明显增加。研究认为,苍耳子提取物对斑马鱼胚胎发育有毒性作用,能够兴奋斑马鱼胚胎心率并增加其游行速度。  相似文献   

4.
CHD5蛋白是一种ATP依赖性染色质重塑解旋酶,属于CHD家族.CHD家族成员在胚胎发育及肿瘤发生发展过程中具有重要的作用.前期研究发现CHD5在多种不同类型的肿瘤中发挥抑癌功能,但不清楚CHD5是否影响早期胚胎干细胞分化.本研究发现随着胚胎干细胞向神经前体细胞的分化,CHD5的表达显著上调.干扰CHD5的表达之后对细胞进行向神经前体细胞分化的诱导,发现POU5F1和NANOG等胚胎干细胞标志基因表达上调,Wnt信号通路激活,而PAX6和SOX1等神经前体细胞的标志基因表达得以抑制,表明CHD5在胚胎干细胞向神经前体细胞分化过程中具有重要功能.  相似文献   

5.
心肌细胞是研究心血管疾病的重要工具之一,但是人类心肌细胞较难获得和培养.为人类胚胎干细胞诱导分化成心肌细胞提供一个有用的实验方法和鉴定方案.人胚胎干细胞以其多向分化的特性为体外研究提供了细胞资源.在人胚胎干细胞诱导分化为心肌细胞的过程中,通过荧光定量聚合酶链式反应(polymerase chain reaction,PCR)检测发现,在分化过程中干细胞标记物Cripto,Dnmt3b,Wnt3,KIF4,Oct4,SOX2和Nanog表达下降,心肌特异性结构蛋白cTnT和α-actinin以及心脏前体细胞分化标记物Nkx2.5表达上升.分化完成后用免疫荧光检测心肌特异性结构蛋白Tnn T2和α-actinin,通过分析Tnn T2阳性细胞的比例,α-actinin阳性细胞的比例,以及Tnn T2和α-actinin双阳性细胞的比例发现,在所提出的胚胎干细胞诱导分化体系中,三者比例分别为90.80%,91.00%,90.91%,表明在此诱导分化条件下人胚胎干细胞可成功分化成为心肌细胞.成功建立了人胚胎干细胞来源的心肌细胞模型以及基于标记物荧光定量PCR及免疫荧光系统检测的鉴定方案,为未来心血管疾病的基础研究及心脏毒性药物检测奠定了一定的基础.  相似文献   

6.
对氯化镉、硝酸铅、硫酸铜3种重金属单一以及联合情况下对早期斑马鱼胚胎发育毒性的影响进行考察,并采用不同浓度的迷迭香酸进行干预,同时观察96 hpf胚胎的死亡率和孵化率.Cd-Pb、Cd-Cu、Pb-Cu、Cd-Pb-Cu对斑马鱼胚胎的毒性作用类型分别为协同作用、协同作用、拮抗作用、协同作用.60μmol/L RA对斑马鱼胚胎死亡、幼鱼畸形及胚胎孵化率无明显影响.Cd~(2+)-Pb~(2+)-Cu~(2+)联合处理,胚胎死亡率明显上升,60μmol/L RA与Cd~(2+)-Pb~(2+)-Cu~(2+)联合处理,胚胎死亡率降低约20%(P<0.01);胚胎凋亡细胞数目明显减少,Bcl-2/Bax的基因表达水平明显上调(P<0.01),Caspase 3基因表达下调(P<0.05).表明RA对Cd~(2+)-Pb~(2+)-Cu~(2+)的联合毒性具有保护作用,其机制可能与上调Bcl-2/Bax,降低Caspase 3基因表达,减少胚胎细胞凋亡有关.  相似文献   

7.
目的:观察大蒜素对人肺腺癌细胞SLC-89增殖的影响。方法:不同浓度的大蒜素与SLC-89细胞共培养72 h,运用MTT法测定大蒜素的IC50。将IC50、IC50/2、IC50/4剂量的大蒜素与SLC-89细胞共培养72 h后,运用端粒重复序列扩增-酶联免疫吸附法分别测定细胞端粒酶活性,运用流式细胞技术测定细胞PCNA的表达率。加入等量生理盐水共培养作为对照组。结果:大蒜素能抑制SLC-89细胞的增殖,其IC50为79.8μg/mL,IC50和IC50/2剂量的大蒜素能显著抑制SLC-89细胞端粒酶的活性,IC50、IC50/2、IC50/4剂量的大蒜素都能显著抑制SLC-89细胞PCNA的表达。结论:大蒜素能抑制SLC-89细胞的增殖,其PCNA的表达比端粒酶活性更容易受到下调。  相似文献   

8.
目的探讨肉苁蓉水提液对猪早期体外发育胚胎中一氧化氮浓度的影响,以研究肉苁蓉促进猪胚胎发育的药理作用。方法将采集的猪卵母细胞随机分为试验组和对照组,试验组在胚胎培养时在基础液中加入50μg/mL肉苁蓉水提液。将培养至囊胚阶段的胚胎取出,用Griess试剂法测定囊胚细胞中NO含量。结果细胞中NO含量显著低于对照组(P<0.05)。结论肉苁蓉水提液减少了胚胎细胞中NO含量,这可能是其促进细胞体外发育的作用机理之一。  相似文献   

9.
胚胎干细胞是从哺乳动物胚胎发育早期的囊胚的内细胞团内分离出来的一类细胞,具有自我更新和全能性的基本特征.作者利用M13噬菌体展示技术筛选与未分化的小鼠胚胎干细胞R1表面特异结合的多肽.实验利用未分化的小鼠胚胎干细胞为筛选靶细胞,分化的小鼠胚胎干细胞为吸附细胞,进行3轮的消减筛选,经细胞ELISA鉴定,噬菌体DNA测序和多肽序列分析,得到13条能与小鼠胚胎干细胞特异结合的多肽.通过BLASTP比对发现有11个体内的同源蛋白,为进一步研究小鼠胚胎干细胞表面分子提供研究基础.  相似文献   

10.
采用响应面法优化同时提取牡丹籽粕多酚和黄酮并检测其抗氧化和降糖活性,最优工艺为乙醇质量分数90%,提取温度85℃,提取时间50 min,料液比1∶40,在此条件下得到的多酚和黄酮提取量分别为(17.59±0.82)mg/g、(0.74±0.09)mg/g,并采用D101大孔树脂对牡丹籽粕提取液进行纯化得到牡丹籽粕多酚和黄酮成分,该成分对DPPH自由基、ABTS自由基的清除能力的IC50值分别为(313.67±42.67)μg/mL、(243.67±22.12)μg/mL,对铁离子还原能力为(438.78±3.36)μmol TE/g,对α-葡萄糖苷酶的半数抑制浓度IC50值为(31.11±2.44)μg/mL,稍优于阿卡波糖IC50值(34.42±1.58)μg/mL.牡丹籽粕多酚和黄酮富集成分具有较好的抗氧化和降血糖活性.  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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