Convenient synthesis of D‐threo‐[dichloroacetyl 1–14C] chloramphenicol

A convenient synthesis of chloramphenicol labelled with carbon‐14 in the dichloroacetyl group at the 1 position is described. It was prepared as part of a 4‐step sequence from [1 ‐ ¹⁴C] glycine and the product was purified by preparative HPLC. A radiochemical yield of 47% was obtained based on [1 ‐ ¹⁴C] glycine and the product had a specific activity of 0.47 mCi/mmol. The procedure can be employed for the synthesis of high specific activity [¹⁴C] chloramphenicol, labelled at 1, 2 or both the positions of dichloroacetyl group. Copyright © 2005 John Wiley & Sons, Ltd.     

γ-亚麻酸乙酯的合成研究

目的确定合成γ 亚麻酸乙酯的最佳工艺路线。方法以黑加仑油为原料采用尿素包和、柱色谱法、酸催化法等联合方法分离及合成γ 亚麻酸乙酯。结果确定黑加仑油经 2～ 3次尿素包和 ,反应温度 80℃ ,反应时间90min ,3%盐酸作酸性溶媒 ,乙醇和γ 亚麻酸比例为 3∶1的制备工艺。结论酸催化法合成γ 亚麻酸乙酯工艺简便 ,易于操作 ,产品收率高、稳定性好。     

氯氟乙酯(21例)和地西泮(22例)治疗焦虑障碍的疗效和安全性比较

目的评价氯氟     

雷公藤提取物固体脂质纳米粒水分散体的制备及体外透皮吸收

制备雷公藤乙酸乙酯提取物固体脂质纳米粒水分散体,并初步研究了体外透皮行为.     

6,7-二氟-4-羟基-2-甲氧甲硫基-3-喹啉羧酸乙酯的合成

3,4-二氟苯胺在三乙胺存在下与二硫化碳生成芳基取代的二硫代氨基甲酸后与氯甲酸乙酯反应得到3,4-二氟苯基异硫氰酸酯,先后与由丙二酸二乙酯在无机碱中成的盐和氯甲基甲醚反应后加热环合,得到氟喹诺酮类抗菌剂普卢利沙星的中间体6,7-二氟-4-羟基-2-甲氧甲硫基-3-喹啉羧酸乙酯,总收率85.7%.     

氯氟乙酯(34例)和地西泮(32例)治疗焦虑障碍的疗效和安全性比较

当前 ,焦虑症及多种疾病引起的焦虑障碍日益增多 ,成为心理障碍中的一个难题 ,往往表现为自主神经的系列变化。氯氟乙酯 (ethylloflazepate)是由法国赛诺菲 (Sanofi)公司合成的新型苯二氮(benzodiazepines)类抗焦虑药[1,2 ] ,通过加强GABA的突触间传递 ,选择性抑制大脑边缘     

阿魏酸乙酯的药理活性及其机制研究

目的 :观察阿魏酸乙酯的药理活性及其机制。方法 :在兔富含血小板血浆 (PRP)中加入阿魏酸乙酯和阿魏酸 ,用ADP诱导血小板的集聚 ,用TYXN 91智能血液凝集仪观察血小板聚集率 ,激光共聚焦显微镜观察血小板细胞聚集时细胞内钙离子的变化情况。制备CCl4肝损伤小鼠模型 ,取血清测定谷丙转氨酶 (ALT)、谷草转氨酶 (AST)活性 ,取肝组织测定丙二醛 (MDA)水平及超氧化物歧化酶 (SOD)活性。结果 :不同浓度的阿魏酸乙酯 ,对ADP诱导的血小板聚集抑制百分数均显著高于等浓度的阿魏酸(n =8,P <0 .0 5 )。在阿魏酸乙酯作用下ADP诱导的血小板细胞内钙离子荧光强度的变化 (ΔFI)为4 .6± 1.7,明显低于对照组ΔFI值 (10 .3± 2 .6 ,n =8,P <0 .0 1)。阿魏酸乙酯可使肝损伤小鼠组织MDA、血清ALT、AST含量显著低于对照组 ,而肝组织的SOD水平显著高于对照组。结论 :阿魏酸乙酯抑制ADP诱导的血小板聚集作用及对CCl4引起的小鼠急性肝损伤的保护作用均比阿魏酸强。     

Effect of microfluidization parameters on the physical properties of PEG-PLGA nanoparticles prepared using high pressure microfluidization

The objective of this work was to develop uniformly distributed poly(ethylene glycol) grafted poly(lactide-co-glycolide) (PEG-PLGA) nanoparticles of mean size range ～100–200 nm using ethyl acetate as the solvent. In the multiple emulsion solvent evaporation method a high pressure microfluidization process was adopted to produce the W/O/W multiple emulsion. Non-toxic ethyl acetate was used to solubilize PEG-PLGA. The mean size of nanoparticles obtained was less than 180 nm. The particle size and size distribution were dependent on the microfluidization conditions applied. Mean particle size steadily increased from 121 nm at three passes to 172 nm at 20 passes of the microfluidizer, indicating that over-processing may be detrimental to PEG-PLGA nanoparticles prepared using this technique. There was no significant alteration of the PEG-PLGA matrix, as evidenced from the differential scanning calorimetric studies.     

Tissue‐specific and time‐dependent clonal expansion of ENU‐induced mutant cells in gpt delta mice

DNA mutations play a crucial role in the origins of cancer, and the clonal expansion of mutant cells is one of the fundamental steps in multistage carcinogenesis. In this study, we correlated tumor incidence in B6C3F1 mice during the period after exposure to N ‐ ethyl‐N‐nitrosourea (ENU) with the persistence of ENU‐induced mutant clones in transgenic gpt delta B6C3F1 mice. The induced gpt mutations afforded no selective advantage in the mouse cells and could be distinguished by a mutational spectrum that is characteristic of ENU treatment. The gpt mutations were passengers of the mutant cell of origin and its daughter cells and thus could be used as neutral markers of clones that arose and persisted in the tissues. Female B6C3F1 mice exposed for 1 month to 200 ppm ENU in the drinking water developed early thymic lymphomas and late liver and lung tumors. To assay gpt mutations, we sampled the thymus, liver, lung, and small intestine of female gpt delta mice at 3 days, 4 weeks, and 8 weeks after the end of ENU exposure. Our results reveal that, in all four tissues, the ENU‐induced gpt mutations persisted for weeks after the end of mutagen exposure. Clonal expansion of mutant cells was observed in the thymus and small intestine, with the thymus showing larger clone sizes. These results indicate that the clearance of mutant cells and the potential for clonal expansion during normal tissue growth depends on tissue type and that these factors may affect the sensitivity of different tissues to carcinogenesis. Environ. Mol. Mutagen. 58:592–606, 2017. © 2017 Wiley Periodicals, Inc.