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81.
Kim EK Kwon KB Han MJ Song MY Lee JH Lv N Ka SO Yeom SR Kwon YD Ryu DG Kim KS Park JW Park R Park BH 《Experimental & molecular medicine》2007,39(2):149-159
We demonstrated previously that Coptidis rhizoma extract (CRE) prevented S-nitroso-N-acetylpenicillamine-induced apoptotic cell death via the inhibition of mitochondrial membrane potential disruption and cytochrome c release in RINm5F (RIN) rat insulinoma cells. In this study, the preventive effects of CRE against cytokine-induced beta-cell death was assessed. Cytokines generated by immune cells infiltrating pancreatic islets are crucial mediators of beta-cell destruction in insulin-dependent diabetes mellitus. The treatment of RIN cells with IL-1beta and IFN-gamma resulted in a reduction of cell viability. CRE completely protected IL-1beta and IFN-gamma-mediated cell death in a concentration-dependent manner. Incubation with CRE induced a significant suppression of IL-1beta and IFN-gamma-induced nitric oxide (NO) production, a finding which correlated well with reduced levels of the iNOS mRNA and protein. The molecular mechanism by which CRE inhibited iNOS gene expression appeared to involve the inhibition of NF-kappaB activation. The IL-1beta and IFN-gamma-stimulated RIN cells showed increases in NF-kappaB binding activity and p65 subunit levels in nucleus, and IkappaB alpha degradation in cytosol compared to unstimulated cells. Furthermore, the protective effects of CRE were verified via the observation of reduced NO generation and iNOS expression, and normal insulin-secretion responses to glucose in IL-1beta and IFN-gamma-treated islets. 相似文献
82.
Chenglin Y Yiqun Y Ye Z Na L Xiaoya L Jing L Ming J 《Langmuir : the ACS journal of surfaces and colloids》2012,28(25):9211-9222
Self-assembled polymeric micelles can be used as efficient particulate emulsifiers. To explore the relationship between the structure and the oil-water interfacial behavior of the micelle emulsifiers, a new type of amphiphilic random copolymer, poly{(styrene-alt-maleic acid)-co-[styrene-alt-(N-3,4-dihydroxyphenylethyl-maleamic acid)]} (SMA-Dopa), was synthesized, self-assembled into micelles, and used as emulsifiers. SMA-Dopa was synthesized via an aminolysis reaction between dopamine and commercial alternating copolymer poly(styrene-alt-maleic anhydride) (SMA). Dopamine moiety facilitated the self-assembly of the SMA-Dopa in selective-solvent into stable micelles, and increased the adsorption of the SMA-Dopa at the oil-water interface. Additionally, the structural transition of the self-assembled SMA-Dopa52 micelles in response to pH and salinity changes were confirmed by means of TEM, AFM, DLS, aqueous electrophoresis techniques, potentiometric titration, and pyrene fluorescence probe methods. Micelles shrunk with increasing salinity, and flocculation of the shrunken primary micelles occurred at salt concentration exceeding 0.1 M. The micelles swelled with increasing pH, and the disassociation of the SMA-Dopa52 micelles occurred at pH above approximately 6.5. The structure of the micelles plays a crucial role in the oil-water interfacial performance. Micelles with various structures were used as emulsifiers to adsorb at the styrene-water and toluene-water interfaces. The emulsifying characteristics demonstrated that self-assembled SMA-Dopa52 micelles with moderately swollen structure (at 2 < pH < 6) combine the advantages of the solid particulate emulsifiers and polymeric surfactants, possessing excellent emulsifying efficiency and good emulsion stability. Moreover, the emulsifying performance of the SMA-Dopa52 micelles could be enhanced by the addition of salt. 相似文献
83.
A new enzymatic process is reported, in which penicillin G acylase from Escherichia coli displays a promiscuous activity in catalyzing the Markovnikov addition of allopurinol to vinyl ester. 相似文献
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Monochalcoplatin: An Actively Transported,Quickly Reducible,and Highly Potent PtIV Anticancer Prodrug 下载免费PDF全文
Dr. Lili Ma Na Wang Rong Ma Cai Li Zoufeng Xu Dr. Man‐Kit Tse Prof. Dr. Guangyu Zhu 《Angewandte Chemie (International ed. in English)》2018,57(29):9098-9102
Recently, PtIV prodrugs have attracted much attention as the next generation of platinum‐based antineoplastic drug candidates. Here we report the discovery and evaluation of monochalcoplatin, a monocarboxylated PtIV prodrug that is among the most cytotoxic PtIV prodrugs to date. Compared with its dicarboxylated counterpart chalcoplatin, monochalcoplatin accumulates astonishingly effectively and rapidly in cancer cells, which is not ascribed to its lipophilicity. The prodrug is quickly reduced, causes DNA damage, and induces apoptosis, resulting in superior cytotoxicity with IC50 values in the nanomolar range in both cisplatin‐sensitive and ‐resistant cells; these IC50 values are up to 422‐fold higher than that of cisplatin. A detailed mechanistic study reveals that monochalcoplatin actively enters cells through a transporter‐mediated process. Moreover, monochalcoplatin shows significant antitumor activity in an in vivo colorectal tumor model. Our study implies a practical strategy for the design of more effective PtIV prodrugs to conquer drug resistance by tuning both cellular uptake pathways and activation processes. 相似文献
87.
基于《化学教育》等期刊文献和核心素养的研究成果,分析了关系式在初中化学计算中的地位和作用。通过“关系式在初中化学计算中的应用”课例,提出了高效复习的建议:要宏观认识复习课的目标和功能,帮助学生形成基本的化学观念、提高问题的解决能力、树立自信心。还应精心设计好各个微环节的活动,达到复习效益最大化。 相似文献
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以3-(对甲基)苯胺甲烯基-6-甲基-5,6-二氢-二氢吡喃-2,4'-二酮为例,用半经验量子化学方法和UHF/6-311G水平上的从头算研究了3-芳胺甲烯基-6-烷基-5,6-二氢-二氢吡喃-2,4'-二酮类农药化合物催化氢化的反应机理.通过对反应物、中间物和产物的生成热、净电荷、键序以及前线轨道能量的计算和分析认为标题化合物的催化氢化反应不仅发生了碳碳双键的加成反应,还同时发生了碳氮键的催化氢解反应. 相似文献