目的研究维康醇对肝癌细胞增殖、细胞周期和细胞凋亡作用的影响。方法以不同浓度维康醇处理对数生长期人肝癌细胞HepG2,利用MTT法测定维康醇对细胞的增殖抑制作用,流式细胞仪PI单染检测细胞周期分布情况的改变,流式细胞仪Annexin V FITC/PI双标记法检测细胞凋亡率。结果 MTT结果显示:维康醇对HepG2细胞具有明显的生长抑制作用并呈浓度和时间依赖性。流式细胞术结果显示:30μmol/L维康醇作用于HepG2细胞48 h后,处于G2/M期的细胞比例显著升高,同时伴随G1/G0期细胞比例下降,与对照组相比差异有统计学意义(P<0.05)。Annexin V FITC/PI染色检测结果显示:30μmol/L维康醇作用于HepG2细胞48 h后,细胞凋亡率显著升高,与对照组相比差异有统计学意义(P<0.05)。结论维康醇对肝癌细胞有明显的增殖抑制作用,并具有浓度和时间依赖性;维康醇通过引起细胞周期阻滞、诱导细胞凋亡发挥其抗肝癌作用。
贾斯丁.曼德斯(Justin Mendes),美国圣母学院文学学士,迈阿密大学法学博士,自2004年起,先后在沈阳理工大学、东北大学执教。文章描述了一位有经验的英语作为第二语言(Englishasa Second Language,ESL)教学的教师眼中的中国英语教育。作者提出,中国ESL教育的软肋在于标准的缺失,对英语语言教育目的的认识缺乏深度,教育的商品化,学生兴趣的缺乏和教师对学生潜能的低估;而优势在于学生自身所具有的文化传统、基本素质、学习态度和创造能力。
Biapenem, a new parenteral carbapenem, has been widely used for treating bacterial infections. A simple, effective and accurate method based on solid-phase extraction （SPE） and HPLC was developed for the quantitative determination of biapenem in human plasma. Stability and feasibility of the method was validated through a series of experiments. Using Vitamin B6 as an internal standard, analyte was separated on a Capcell Pak C18 column after SPE on Oasis hydrophilic-lipophilic balance （HLB） cartridge. The mobile phase was comprised of 0.05 mol/L NaH2PO4 （pH 5.7） and methanol （98：2, v/v） at a flow rate of 1.0 mL/min. Ultraviolet absorbance was measured at 300 nm. The calibration curve was linear in the concentration range of 0.04-50.00 μg/mL, and the lower limit of quantification was as low as 0.04 μg/mL. Recovery rates of biapenem at 0.10, 5.00, and 25.00 μg/mL were about 70%. The validated method has been successfully applied for quantifying biapenem in human samples and a pharmacokinetic study of 12 healthy volunteers who received three different doses （150, 300 and 600 mg） of biapenem by intravenous infusion. Our method has featured good accuracy and precision, and the processed sample was stable. Therefore, it can be propagated for clinical use.
