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991.
本文采用放射性同位素标记的方法研究了嵌段聚醚型聚氨酯在纯纤维蛋白原溶液中和稀释血浆中的表面纤维蛋白原吸附性规律,考察了聚醚型聚氨酯的特性粘数及溶液体系中的NaCl浓度对材料表面纤维蛋白原吸附性的影响,结果表明,随着聚合物特性粘数的增大,材料表面的纤维蛋白原吸附量呈降低的趋势;溶液体系中盐浓度的降低导致纤维蛋白原凝固性增强,在纯纤维蛋白原溶液中,材料表面纤维蛋白原的吸附量相应增多,而在稀释血浆中,纤维蛋白原的吸附量相应减少,在达到最低值后又有上升的趋向,表明纤维蛋白原在材料表面的吸附还受血浆中其它大分子的影响。 相似文献
992.
Human mini-chromosomes in mouse embryonal stem cells 总被引:3,自引:2,他引:3
We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb
in size into mouse embryonal stem cells. Although these human mini-
chromosomes are stable in hamster and chicken cells, they re-arrange or
segregate aberrantly in the embryonal stem cells and are rapidly lost in
the absence of selection. However, one of the mini-chromosomes re-
arranged, acquired mouse centromeric sequences and was then stably
maintained for at least 60 population doublings in culture. This mini-
chromosome, which is 4 Mb in size, is a candidate for a mouse germ line
chromosome vector.
相似文献
993.
994.
本文分别应用标准12导联系统,Frank正交导联系统和改良Frank正交导联系统记录健康人36例、陈旧性心肌梗塞42例的心室碎裂电位,通过分析这些导联系统中相互垂直或近似垂直的导联上VFP的形态,数量关系,发现改良Frank正导联系统记录VFP较其它导联系统更科学,合理,且操作方便。 相似文献
995.
Kim D Hur DY Kim YS Lee K Lee Y Cho D Kang JS Kim YI Hahm E Yang Y Yoon S Kim S Lee WB Park HY Kim YB Hwang YI Chang KY Lee WJ 《Human immunology》2002,63(7):576-587
Burkitt lymphoma (BL) is a tumor with the characteristics of germinal center B cells. We previously reported that the CM1 (centrocyte/-blast marker 1) molecule is expressed only in germinal center B cells, specifically, in a subpopulation of centroblasts and centrocytes. In the present study, we investigated the apoptosis induced by anti-CM1 in the Ramos and Raji human BL cell lines. The Ramos is protected from apoptosis by the crosslinking of sIgM and the calcium ionophore by the ligation of CD40 with anti-CD40 monoclonal antibodies (mAb) or soluble CD40 ligand (sCD40L). In this investigation on the effect of CM1 on apoptosis in BL cell lines, we found that cellular signaling by CM1 induces apoptosis and decreases cell viability, in BL cell lines cultured for 24 hours with protein-G agarose beads conjugated anti-CM1 mAb. Stimulation by CD40 ligated with sCD40L protected Raji cells from CM1-induced apoptosis, but did not protect Ramos cells. Furthermore, after anti-CM1 mAb stimulation, CD95 expression was upregulated and CD40 expression was unaltered or slightly decreased in Ramos cells, whereas CD95 was downregulated and CD40 was slightly upregulated in Raji cells. The engagement of CD40 by sCD40L enhanced CD95 expression, but the level of CM1 expression was unchanged in Ramos. However, sCD40L downregulated both CD95 and CM1 expression in Raji. In addition, the caspase-8 specific inhibitor blocked CM1-induced apoptosis in Ramos cells, but not in Raji cells. Increased mitochondrial membrane permeabilization was observed only in Raji cells. Moreover, the effector caspase inhibitor, z-DEVD, blocked CM1-mediated apoptosis in both cell lines. We found that CM1-induced apoptosis is achieved via different initiation pathways, which are cell-type dependent. 相似文献
996.
目的为了进一步探索VGF的生物学功能方法分别构建了痘苗病毒天坛株生长因子(Vacciniagrowthfactor,VGF)基因细胞膜外结构域(VGFsl)的真核及原核表达系统,在相应的细胞中获得了单独表达(真核)和融合表达(原核)。结果初步纯化的VGFsl表达产物能够与上皮生长因子(EGF)的受体结合,并刺激受体中酪氨酸残基发生磷酸化反应。与EGF相比,VGFsl表达产物刺激EGF受体自身磷酸化的能力更强。结论上述结果为VGF在病毒感染过程中的作用以及VGF作为新型多肽类药物的研究提供了有价值的线索。 相似文献
997.
In the rabbit, lens disruption produced very little histological changes in the retina. However, lens disruption after skin graft produced an alarming picture with infiltration of inflammatory cells and degeneration of retinal layers. 相似文献
998.
J. H. Lee S. S. Lee J. S. Park S. Lee M. H. Yang T. Y. Yoon 《Journal of Korean medical science》1995,10(6):399-405
Recent studies have suggested a probable association between Epstein-Barr virus (EBV) and nasal/nasopharyngeal T cell lymphomas but the role of oncogenes or tumor suppressor genes is poorly understood. We have studied the frequency of p53 expression and its relation to the EBV infection in 33 Korean patients with head and neck (H&N) lymphomas. All cases (23 B cell & 10 T cell) were immunostained for p53 protein using the mAb D07 (Novocastra) and the avidin biotin peroxidase method. EBER in situ hybridization was performed using a fluorescein conjugated EBV oligonucleotide probe (Dako). Among 33 lymphomas, 16 cases stained positively for p53 protein. P53 expression was frequent both in higher grade lymphomas and in advanced stage. Nine cases were EBER positive, EBER was more commonly found in T cell lymphomas than in B cell lymphomas (70% vs 8.7%). EBER positive lymphomas showed a higher frequency of p53 positivity than EBER negative lymphomas (78% vs 38%), although the difference was not statistically significant (p = 0.095). These findings indicate altered expression of p53 protein occurs in H&N lymphomas, especially in late event lymphoma progression and appears to play a role in the development of EBER positive T cell lymphomas. 相似文献
999.
弓形虫分离株表膜脂肪酸的色质谱分析 总被引:2,自引:0,他引:2
本文采用有机质谱法(GC/MS)对弓形虫不同分离株,虫体表膜脂肪酸的种类和含量进行观察分析,实验结果表明弓形虫速殖子细胞膜含有6种主要脂肪酸,范围在C14-C18之间,分别为肉豆寇酸、棕榈油酸、软脂酸、硬脂酸、油酸和亚油酸,而油酸和软脂酸约占总脂肪酸含量的70%(52-84%)。本室自畸胎儿分离获得的SH多个虫株的脂肪酸含量及组分与国际标准人源RH株相一致,而SH4,SH(10)与PP株,RT株相似,与平行观察的人和哺乳动物细胞膜的脂肪酸在含量与组分上均有明显差异,为鉴定分离的弓形虫株提供了实验依据。 相似文献
1000.
Roland S. Liblau Cecelia I. Pearson Kevan Shokat Roland Tisch Xiao-Dong Yang Hugh O. McDevitt 《Immunological reviews》1994,142(1):193-208