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排序方式: 共有9193条查询结果,搜索用时 15 毫秒
961.
962.
Z Guo J Wang L Meng Q Wu O Kim J Hart G He P Zhou J R Thistlethwaite M L Alegre Y X Fu K A Newell 《Journal of immunology (Baltimore, Md. : 1950)》2001,167(9):4796-4800
Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection. 相似文献
963.
用Factin 特异性FITCphalloidin荧光染料,观察肺炎链球菌(Streptococcus pneumoniae)作用A549细胞前后的Factin细胞骨架重排情况;用细胞松弛素D预处理A49细胞,观察肺炎链球菌对A549细胞的侵袭率;使用Datrolene预处理A549细胞,观察其与Factin细胞骨架重排百分率间是否存在剂量依赖关系;用Fura2/AM荧光探针负载A549细胞后测定肺炎链球菌粘附A549细胞后的胞内Ca2+浓度。结果发现肺炎链球菌作用A549细胞后,Factin细胞骨架呈块状、丝状聚集;而松弛素D可明显降低肺炎链球菌对A549细胞的侵袭率;肺炎链球菌粘附A549细胞后胞内Ca2+高于对照;Datrolene可部分抑制A549细胞Factin细胞骨架重排,且与Factin细胞骨架重排百分率间存在量效关系。以上结果提示肺炎链球菌可通过Ca2+细胞信号转导途径触发A549细胞Factin细胞骨架重排,进而导致肺炎链球菌侵袭A549细胞。 相似文献
964.
C Q Meng X S Zheng L A Holt L K Hoong P K Somers R R Hill U Saxena 《Bioorganic & medicinal chemistry letters》2001,11(14):1823-1827
A series of nitrobenzene compounds has been discovered as potent inhibitors of VCAM-1 expression and, therefore, potential drug candidates for autoimmune and allergic inflammatory diseases. Structure-activity relationship (SAR) studies showed that a nitro group and two other electron-withdrawing groups are essential for these compounds to be potent inhibitors of VCAM-1 expression. 相似文献
965.
花椒种籽油的含蜡量测定与脱蜡 总被引:7,自引:0,他引:7
花椒种籽油的含蜡量测定与脱蜡是长期困扰花椒种籽油处理的一项关键技术,本研究通过分析混合压榨制备的花椒种籽油,花椒籽种壳油及种仁油的含蜡量,研究了5种脱蜡方法脱除花椒籽油中蜡质的脱蜡效果,确定了脱除花椒籽油中蜡质的有效方法,研究结果表明,花椒籽油的含蜡量在15-20%,左右,而这些蜡质基本上都含在种壳油内一即种壳上,种仁油基本不含蜡质,脱除花椒籽油中蜡质的合理方法应是:(1)含蜡量相对较低的精制粗油可选用表面活性剂法脱蜡;(2)当含蜡量相对较高时,为降低脱蜡过程中油的耗损率可选用分步脱蜡法脱蜡;(3)需进行碱炼的油,可在碱炼过程中将蜡质与游离脂肪酸一半除去。 相似文献
966.
967.
968.
Wang Meng Feng Zhigang Li Xiaoxi Sun Shulan Lu Li 《Molecular and cellular biochemistry》2021,476(6):2561-2571
Molecular and Cellular Biochemistry - LncRNAs have been proposed to be associated with the tumorigenesis and progression of oral squamous cell carcinoma (OSCC). LncRNA HLA complex group 22 (HCG22)... 相似文献
969.
Wang Ting-Ting Zhu Chen-Ye Zheng Shuang Meng Cai-Cai Wang Tian-Tian Meng Dan-Hua Li Yi-Jun Zhu Hao-Miao Wang Feng-Shan Sheng Ju-Zheng 《Applied microbiology and biotechnology》2018,102(11):4785-4797
Applied Microbiology and Biotechnology - Avibacterium paragallinarum is a Gram-negative bacterium that causes infectious coryza in chicken. It was reported that the capsule polysaccharides... 相似文献
970.
Shu-Qun Liu Yan Tao Zhao-Hui Meng Yun-Xin Fu Ke-Qin Zhang 《Journal of molecular modeling》2011,17(2):289-300
The native serine protease proteinase K binds two calcium cations. It has been reported that Ca2+ removal decreased the enzyme’s thermal stability and to some extent the substrate affinity, but has discrepant effects on
catalytic activity of the enzyme. Molecular dynamics simulations were performed on the Ca2+-bound and Ca2+-free proteases to investigate the mechanism by which the calciums affect the structural stability, molecular motions, and
catalytic activity of proteinase K. Very similar structural properties were observed between these two forms of proteinase
K during simulations; and several long-lived hydrogen bonds and salt bridges common to both forms of proteinase K were found
to be crucial in maintaining the local conformations around these two Ca2+ sites. Although Ca2+ removal enhanced the overall flexibility of proteinase K, the flexibility in a limited number of segments surrounding the
substrate-binding pockets decreased. The largest differences in the equilibrium structures of the two simulations indicate
that, upon the removal of Ca2+, the large concerted motion originating from the Ca1 site can transmit to the substrate-binding regions but not to the catalytic
triad residues. In conjunction with the large overlap of the essential subspaces between the two simulations, these results
not only provide insight into the dynamics of the underlying molecular mechanism responsible for the unchanged enzymatic activity
as well as the decreased thermal stability and substrate affinity of proteinase K upon Ca2+ removal, but also complement the experimentally determined structural and biochemical data. 相似文献