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1.
描述了Laminin五肽(YIGSR)对胃癌细胞系MGc-803的体外抑制作用,在多肽浓度为1mg/ml时抑制率高达73%。抑制作用的机理可能是Laminin五肽竞争了肿瘤细胞上Laminin受体,从而封闭了肿瘤细胞对基底膜的结合及增殖。因此,利用Laminin五肽一类的药物有可能为肿瘤术后防止扩散提供一个新方法。  相似文献   

2.
拓扑特肯体内外抗肿瘤作用的研究   总被引:1,自引:0,他引:1  
测定了拓扑特肯对5种体外培养人肿瘤细胞株的生长抑制作用及对小鼠移植性肿瘤的抑制作用。结果显示拓扑特肯对各体外肿瘤细胞都有明显的细胞毒作用,除了人胃癌BGC-803的IC50为3.87μg/mL外,对其它瘤株的IC50均小于0.1μg/mL。在1.0mg/kg,2.0mg/kg剂量下,拓扑特肯对小鼠肉瘤S180的抑制率分别为32.0%、33.8%;对小鼠肝癌H22的抑制率分别为31.4%、42.1%  相似文献   

3.
水稻根谷氨酰胺合成酶同工酶某些性质研究   总被引:1,自引:1,他引:0  
对水稻根两种不同形式的胺合成酶进行了动力学性质研究,GSm对热比较稳定,而GSb比较敏感,GS2a的最适温度为55℃,GSrb为43℃,GSrc的最适PH都为7.5GSra对L-谷氨酸,经胺和ATP的表观Kia分别为4.16,0.60和0.34,而GS分别为51.73,0.60和0.58,MSO对两均表现为竞争性抑制作用。  相似文献   

4.
研究了谷氨酸阴离子(G-)和晶种对其晶体二次成核与生长的影响.结果表明成核速率随晶种粒度和晶种量减少而减少;在高过饱和度时G-对成核有促进作用,而在低过饱和度时则有抑制作用;晶体生长速率随粒度减小而增大;G-对晶体生长有抑制作用;结晶时使用粒度小的晶种可得到粒度分布较均匀的晶体.  相似文献   

5.
固相合成胸腺五肽的分离与纯化   总被引:2,自引:0,他引:2  
胸腺五肽(TP5)是一种很有发展前景的药物,具有胸腺素的全部生理功能固相合成法是胸腺五肽生产的主流技术,目前,对固相合成的五肽一般采用反相色谱技术纯化,但效率低、成本高,仅限于小规模制备实验采用离子交换法纯化,并进行了方案优化,发现在pH4.4醋酸盐缓冲液平衡、盐梯度洗脱条件下纯化TP5,一步分离纯度可达98.23%该法可以满足大规模制备的要求,且成本很低  相似文献   

6.
目的:探讨维生素A抑制Shope肿瘤细胞生长的机理。方法:电镜观察Shope肿瘤细胞凋亡的形态学改变:琼脂糖凝胶电泳进行DNA片段化;流式细胞仪检测凋亡细胞的百分比。结果:电镜下可VA诱导的Shope肿瘤细胞变小,细胞浆固缩,染色质聚集并靠近核膜,在1.5%琼脂糖凝胶电泳中,Shope肿瘤细胞DNA呈现明显的阶梯状图谱。流式细胞仪检测经10-5MV作用24h、48h、72h后,凋亡细胞百分比分别为:17.1%、22.4%、32.4%。结论:以上结果表明,VA对Shope肿瘤细胞有明显的抑制作用。  相似文献   

7.
报道了青霉素G钠对绿巨人愈伤组织诱导、分化及苗生长的初步结果。试验表明:青霉素G钠对诱导叶片愈伤组织的产生有抑制作用,而对愈伤组织的分化有促进作用,效果最好的浓度为60万u·L^-1,平均每块愈伤组织可分化7.0个不定芽;低浓度的青霉素G钠(20万u·L^-1)对试管苗的生长有促进作用,同时也促进根系的发育;而高浓度的青霉素G钠对试管苗的生长有抑制作用,并随着浓度的提高而增强,在生根培养基中添加低  相似文献   

8.
抑癌基因p27是一个细胞周期依赖性激酶抑制子CKI(CDK inhibitor),对细胞周期起着负调控的作用,将p27基因克隆到表达载体pcDNA,转染到肿瘤细胞MCF7中,筛选到稳定表达株.p27基因的过量表达确实对肿瘤细胞的生长产生了抑制作用,并且引发了部分肿瘤细胞的凋亡.  相似文献   

9.
用SDS-PAGE对经超声波处理的气味沙雷氏菌全菌体进行分离,切胶分别洗脱,经丙酮沉淀、脱盐处理后得到九个蛋白组分,将九个组分分别用L929,QGY肿瘤细胞为靶细胞进行细胞毒性试验(MTT),经初步鉴定从此且分具有抗癌细胞活性,组分F6相对分子质量范围为28000-33000,其抑制50%细胞生长的蛋白浓度(IC50);对L929细胞为0.046mg/ml对QGY细胞为0.01250mg/ml,活  相似文献   

10.
海藻真菌抗肿瘤活性的初步研究   总被引:2,自引:2,他引:0  
从福建漳州浯屿岛和漳州浮宫海岸潮问带采集到的10种海藻中分离到66株海藻真菌.采用MTT法对其发酵液乙酸乙酯抽提物的抗肿瘤活性进行检测.发现34株菌株对KB和/或Raji肿瘤细胞具有显著的抑制活性,占供测菌株的52%.其中对KB细胞有抑制作用的菌株有21株.对Raji细胞有抑制作用的菌株有30株.对两种肿瘤细胞均有抑制作用的菌株有17株.分别占活性菌株的62%、88%和50%.实验结果表明,海藻真菌是潜在的抗肿瘤药物资源.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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