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991.
992.
晚孕期胎盘因子对小鼠淋巴细胞增殖的影响 总被引:1,自引:0,他引:1
通过晚孕期胎盘因子(PF)对小鼠淋巴细胞体外增殖的作用,探讨PF对正常机体免疫系统和免疫功能的效应。分离小鼠淋巴细胞,用ConA刺激其增殖,并分别与晚孕期不同浓度的PF作用,于48 h和72 h用活体染料羧基荧光素乙酰乙琥珀酰亚胺酯(CFSE)标记,流式细胞术检测增殖。于48 h碘化丙啶染色,流式细胞术检测细胞周期分布。结果显示,晚孕期PF在48 h和72 h时间点均能显著促进ConA诱导的小鼠淋巴细胞增殖反应,且效应与剂量呈正相关。晚孕期各浓度PF组G0期所占比率均显著低于对照组,且浓度越大,比率越低,组间两两比较有统计学意义。各浓度PF组S期所占比率均显著高于对照组,各浓度PF组G2/M期所占比率均显著高于对照组,25%PF组G2/M期所占比率均显著高于5%PF组和15%PF组。晚孕期PF通过促进小鼠淋巴细胞由G1期向S和G2/M期而促进ConA刺激小鼠淋巴细胞的增殖反应,提示PF具有免疫调节的功能,可以提高机体的免疫功能。 相似文献
993.
通过对HPV L1序列进行比对,发现HPV L1 C-末端存在长30个氨基酸残基的保守序列短肽;出于检测短肽是否可以诱生HPV多种型别交叉抗体的目的,将该序列短肽加弗氏佐剂用于日本大耳白兔和BALB/c小鼠免疫,然后用ELISA方法检测此免疫动物血清及其分泌物中的IgG抗体滴度,发现此免疫动物体内已诱生出高滴度的血清IgG抗体(>1∶20000);再用ELISA、免疫组织化学和Western blot的方法对此诱生血清抗体与HPV阳性宫颈癌细胞株的反应情况进行检测,发现这些短肽抗血清可与16、18型HPV L1很好地进行反应,其对照组呈现阴性。这一研究结果表明短肽可以诱生HPV多种型别交叉抗体。它对后续研发HPV L1广谱疫苗或检测试剂盒具有重要意义。 相似文献
994.
995.
Li Yingxian Chen Wei Zhao Linchun Zhang Ji-Quan Zhao Yonglong Li Chun Guo Bing Tang Lei Yang Yuan-Yong 《RSC advances》2022,12(32):20550
Amide is a fundamental group that is present in molecular structures of all domains of organic chemistry and the construction of this motif with high atom economy is the focus of the current research. Specifically, N-methyl amides are valuable building blocks in natural products and pharmaceutical science. Due to the volatile nature of methyl amine, the generation of N-methyl amides using simple acids with high atom economy is rare. Herein, we disclose an atom economic protocol to prepare this valuable motif under DABCO/Fe3O4 cooperative catalysis. This protocol is operationally simple and compatible with a range of aliphatic and (hetero)aromatic acids with very good yields (60–99%). Moreover, the Fe3O4 can be easily recovered and high efficiency is maintained for up to ten cycles.The generation of N-methyl amides using simple acids with high atom economy is rare owning to the volatile nature of methyl amine. Herein, an atom economic protocol was disclosed to prepare this valuable motif under DABCO/Fe3O4 cooperative catalysis.Amide is a fundamental group that is present in molecular structures of all domains of organic chemistry.1 It is widely distributed in natural products, synthetic drugs and functional polymers, and is also the key chemical connection in proteins.2 It has been shown that amide bond formation alone accounts for 65% of all preliminary screening reactions in the pharmaceutical industry.3 This means the generation of amide bonds with high atom efficiency is of high practical importance. And not surprisingly, ‘amide formation avoiding poor atom economy reagents’ was voted as the top challenge for organic chemistry by the ACS Green Chemistry Institute in 2007.3From synthetic point of view, the ideal way to produce amide bonds would be the direct coupling of readily available carboxylic acids and amines, but this process is thermodynamically unfavourable due to the formation of the corresponding carboxylate-ammonium salt,4 therefore, stoichiometric amount of coupling reagents, such as DCC, DIC, EDCI, HATU, HBTU, HCTU, SOCl2, BOP, acid chloride etc, are generally required to sidestep thermal conditions for amide bond formation.5 These reagents are highly successful, but the process generally suffers from poor atom economy and side products removal issue especially in the large-scale applications.5 To overcome these drawbacks, “nonclassical” amide bonds formation routes were investigated.6 In these processes, the catalyst takes the role of a coupling reagent in generating an active ester suitable for amidation in a waste-free manner. However, these processes have not been applied in the preparation of N-methyl amides, probably because the methyl amine was delivered in its hydrochloride salt, alcoholic or aqueous form due to its volatile nature.On a different note, N-methyl amides are extensively presented in numerous natural products and pharmaceutical molecules, as shown in Fig. 1,7 and the methylation of amides is a promising way to improve the pharmacological property of molecules.8 However, the synthesis of N-methyl amides compounds relies heavily on non-catalytic approaches.5,9 Catalytic approaches were also investigated by Hisaeda,10 Kundu,11 Li,12 Guo,13 Yu,14 Maruoka,15 Wang,16 Chen,17 Lamaty18 and their co-workers starting from nitriles, primiary amides, aldoximes, aldehydes, lignin, carbamoylsilane and alcohols. Until recently, Thakur,19 Marce,20 Sadeghzadeh21 and their co-workers developed elegant N-methyl amidation approach starting from carboxylic acids under nano-MgO, diatomite Earth@IL/ZrCl4 and Mg(NO3)2·6H2O catalysis respectively, while limitations like poor substrate scope or sophisticated tailored catalyst still persist. Mindful of all the above issues, developing an N-methyl amidation process of simple carboxylic acids, which is still of great challenge in synthesis, and establishing a broad (hetero)aryl scope with high atom economy from commercial available reagents and catalysts were critical considerations in this study. Moreover, the significance of N-methyl amides combined with our interests in the development of green synthetic approaches motivated us to explore the direct coupling of the carboxylic acids and isothiocyanates. To the best of our knowledge, this is the first successful work using isothiocyanatomethane to prepare N-methyl amides.Open in a separate windowFig. 1Marketed drugs bearing N-methyl amide group.Our initial investigation begins with phenylacetic acid and isothiocyanatomethane as model substrate for condition optimization. Using acetonitrile as solvent, only trace amount of product was detected under catalyst free or p-toluenesulfonic acid (PTSA) catalysis conditions ( Entry Additive Time (h) Catalyst Yield (%) 1 — 24 — 5 2 — 24 PTSA — 3 — 48 TEA 17 4 — 48 DBU 45 5 — 48 DMAP 43 6 — 48 DBN 51 7 — 48 DABCO 65 8 LiBr 48 DABCO 71 9 Mn(OAc)2 48 DABCO 75 10 MnO 48 DABCO 79 11 MgO 48 DABCO 88 12 Al2O3 48 DABCO 85 13 Fe3O4 48 DABCO 98 14 Fe3O4 24 DABCO 75 15b Fe3O4 48 DABCO 80