人参皂甙Rg3对乳腺癌MCF-7线粒体凋亡途径的影响

目的探讨20(R)–人参皂甙Rg3(SPG-Rg3)对人乳腺癌MCF-7细胞的诱导凋亡作用及其可能机制。方法人乳腺癌细胞MCF-7细胞株分为空白对照组、实验对照组及SPG-Rg3多个浓度组。利用MTT法观察人参皂甙Rg3对MCF-7细胞生长的抑制作用,并计算出IC-50,进一步确定其有效浓度;流式细胞术检测人参皂甙Rg3作用后MCF-7细胞周期的变化;利用AnnexinV-EGFP/PI双染法,检测人参皂甙Rg3诱导MCF-7细胞凋亡情况;免疫细胞化学染色检测MCF-7细胞凋亡与Fas、FasL蛋白表达的关系。结果 SPG-Rg3作用48h的IC-50为244.54μg/mL。流式细胞仪检测Rg3使MCF-7的S期细胞比率明显增加(P<0.01),凋亡率明显增加(P<0.01)。免疫细胞化学显示Rg3能使MCF-7细胞胞浆内细胞色素C增加(P<0.01)。结论 SPG-Rg3能诱导乳腺癌MCF-7细胞凋亡,其机制可能与诱导线粒体释放细胞色素C有关。     

新型PPARα/γ双重激动剂618H抗2型糖尿病的实验研究*

目的：研究新型PPARα/γ双重激动剂C618H的抗2型糖尿病作用。方法：采用双荧光素酶报告基因系统，确证C618H对PPARα和PPARγ的激动活性；通过前脂肪细胞分化实验和降脂实验，进一步明确C618H的PPARα/γ双重激动作用；灌胃给药，观察C618H对db／db2型糖尿病小鼠的降糖降脂作用；PT—PCR方法研究C618H的作用机制。结果：C618H有较强的PPARα/γ双重激动活性；能够促进前脂肪细胞分化，降低高脂小鼠的血脂水平；对2型糖尿病小鼠有明显的降糖降脂作用；能够增加不同组织中脂蛋白脂酶（LPL）、脂肪组织特异的脂肪酸转运蛋白（aP2）和葡萄糖转运体4（GluT4）mRNA的表达。结论：C618H是PPARα/γ双重激动剂，对2型糖尿病具有较好的降糖降脂作用。     

溪桫化学成分研究

目的:研究楝科溪桫属植物溪桫[Chisocheton cumingianus subsp.balansae(C.Candolle)Mabber-ley]的小枝及茎皮化学成分。方法:利用正相、反相硅胶柱色谱、Sephadex LH-20凝胶柱色谱、制备HPLC等方法分离化合物,运用MS和NMR等波谱方法解析鉴定化合物结构。结果:从其乙醇提取物之三氯甲烷萃取部位中分离鉴定出10个化合物,分别为4个三萜类化合物:odoratone(1),grandifoliolenone(2),24-表-匹西狄醇A(24-epi-piscidinol A,3),chisiamol F(4);3个倍半萜类化合物:1β,6α-二羟基-4(15)-桉叶烯(1β,6α-dihydroxy-4(15)-eudesmene,5),1β,8α-二羟基-4(15)-桉叶烯(1β,8α-dihydroxy-4(15)-eudesmene,6),环氧泽泻烯(alismoxide,7);3个蒽醌类化合物:大黄酚(8),大黄素(9),大黄素甲醚(10)。结论:10个化合物均首次从该植物中分离得到。     

灵芝多糖拮抗环孢素A,氢化可的松及抗肿瘤药的免疫抑制作用

灵芝多糖在50,100和200μg·ml~1时可完全拮抗环孢素A,丝裂霉素C,氟尿嘧啶和阿糖胞苷对小鼠混合淋巴细胞反应(MLR)的轻度抑制(抑制50％以下)作用,部分拮抗氢化考的松对MLR的严重抑制(抑制50％以上)作用。     

用RP-HPLC法考察头孢噻利与维生素C的配伍稳定性

目的 考察注射用硫酸头孢噻利(第4代头抱类抗生素)与维生素C注射液在5%葡萄糖注射液中的配伍稳定性.方法 用反相高效液相色谱法,测定注射用硫酸头孢噻利与维生素C配伍后两者的含量变化,观察和检测配伍液的外观及pH值的变化.结果 室温下配伍液8h内,外观、pH值及含量无明显变化.结论 注射用硫酸头孢噻利与维生素C注射液在5%葡萄糖注射液中配伍后于室温下8h内可使用.     

Preclinical factors affecting the interindividual variability in the clearance of the investigational anti-cancer drug 5,6-dimethylxanthenone-4-acetic acid

Cancer chemotherapy is characterized by significant interindividual variations in systemic clearance, therapeutic response, and toxicity. These variations are due mainly to genetic factors, leading to alterations in drug metabolism and/or target proteins. The aim of this study was to determine, using a human liver bank (N=14), the interindividual variations in the expression and activity of liver enzymes that metabolize the investigational anticancer drug 5,6-dimethylxanthenone-4-acetic acid (DMXAA), i.e cytochrome P450 (CYP1A2) and uridine diphosphate glucuronosyltransferase (UGT1A9/2B7). In addition, interindividual variations in enzyme inhibition, hydrolysis of DMXAA acyl glucuronide (DMXAA-G) by plasma and hepatic microsomes, and the binding of DMXAA by plasma proteins also were examined. The results indicated that there was approximately one order of magnitude of interindividual variation in the expression of CYP1A2 and UGT2B7, activity of the enzymes toward DMXAA, and inhibition potency (IC(50)) by diclofenac, cyproheptadine, and alpha-naphthoflavone. The enzyme activities toward DMXAA and IC(50) values were closely correlated with enzyme expression. There was a smaller (2- to 3-fold) variation in the enzyme-catalyzed hydrolysis of DMXAA acyl glucuronide in human plasma and liver microsomes (N=6) and in the binding of DMXAA by plasma proteins in humans. In conclusion, the interindividual variability of DMXAA disposition observed in vitro might reflect the greater elimination variability (>one order of magnitude) in Phase I cancer patients. The variability in DMXAA clearance in these cancer patients would be due mainly to differences in its metabolism and its metabolic inhibition by co-administered drugs. To a lesser extent, variability in the clearance of DMXAA could be due to the hydrolysis of its acyl glucuronide and/or its binding to plasma proteins. Further study is needed to examine the genotype-phenotype relationship, and the result, together with therapeutic drug monitoring may provide a useful strategy for optimizing DMXAA treatment.     

CYP2C9、CYP2C19、CYP3A4基因多态性对磺脲类降糖药代谢的影响

磺脲类口服降糖药在人体内主要经过肝脏代谢。肝脏中的细胞色素氧化酶P450是一种重要的药物代谢酶系统,在人群中存在基因多态性,导致药物疗效和不良反应在个体间存在着较大的差异。本文将对CYP450中的几种重要的代谢酶亚型CYP2C9、CYP2C19、CYP3A4的基本结构、基因多态性、种族差异及其对磺脲类降糖药代谢的影响作一综述。     

HPLC法测定华海乙肝泡腾颗粒剂中柴胡皂苷C的含量

目的：为控制华海乙肝泡腾颗粒剂的质量建立测定柴胡皂苷C的方法。方法：采用高效液相色谱法,色谱条件为：ODS柱,以甲醇－水（61：39）为流动相,流速1.0ml/min,检测波长203nm。结果：平均回收率99.3%,RSD＝1.34%。结论：此法可作为控制华海乙肝泡腾颗粒剂质量的方法之一。     

Mechanisms of hepatotoxicity.

This review addresses recent advances in specific mechanisms of hepatotoxicity. Because of its unique metabolism and relationship to the gastrointestinal tract, the liver is an important target of the toxicity of drugs, xenobiotics, and oxidative stress. In cholestatic disease, endogenously generated bile acids produce hepatocellular apoptosis by stimulating Fas translocation from the cytoplasm to the plasma membrane where self-aggregation occurs to trigger apoptosis. Kupffer cell activation and neutrophil infiltration extend toxic injury. Kupffer cells release reactive oxygen species (ROS), cytokines, and chemokines, which induce neutrophil extravasation and activation. The liver expresses many cytochrome P450 isoforms, including ethanol-induced CYP2E1. CYP2E1 generates ROS, activates many toxicologically important substrates, and may be the central pathway by which ethanol causes oxidative stress. In acetaminophen toxicity, nitric oxide (NO) scavenges superoxide to produce peroxynitrite, which then causes protein nitration and tissue injury. In inducible nitric oxide synthase (iNOS) knockout mice, nitration is prevented, but unscavenged superoxide production then causes toxic lipid peroxidation to occur instead. Microvesicular steatosis, nonalcoholic steatohepatitis (NASH), and cytolytic hepatitis involve mitochondrial dysfunction, including impairment of mitochondrial fatty acid beta-oxidation, inhibition of mitochondrial respiration, and damage to mitochondrial DNA. Induction of the mitochondrial permeability transition (MPT) is another mechanism causing mitochondrial failure, which can lead to necrosis from ATP depletion or caspase-dependent apoptosis if ATP depletion does not occur fully. Because of such diverse mechanisms, hepatotoxicity remains a major reason for drug withdrawal from pharmaceutical development and clinical use.     

HMGB1对宫颈癌HeLa细胞凋亡的影响及其作用机制

目的 观察HMGB1对人宫颈癌HeLa细胞生长及凋亡的影响并研究其可能的作用机制.方法 构建HMGB1高表达质粒和RNA干扰质粒,将HMGB1高表达质粒与RNA干扰质粒分别转染到HeLa细胞中,采用MTT实验、PI单染流式细胞术和Annexin V-PI双标法流式细胞术检测HeLa细胞的增殖活性、细胞周期和凋亡情况.采用RT-PCR和western blot法检测HMGB1基因沉默对Caspase-3、bcl-2 和细胞色素C表达的影响.结果 HMGB1高表达载体(pEGFP-N1-HMGB1)与阴性对照质粒分别转染到HeLa细胞,RT-PCR和Western blot结果显示HMGB1重组质粒转染HeLa后可明显增加HMGB1的mRNA 及蛋白表达(P＜0.05).HMGB1干扰病毒载体(HMGB1 SiRNA)与空白病毒载体分别转染到HeLa细胞中,RT-PCR和Western blot结果显示HMGB1 SiRNA转染HeLa后可明显抑制HMGB1的mRNA及蛋白表达(P＜0.05).MTT法检测HMGB1高表达及基因沉默后HeLa的细胞生长曲线,结果显示HMGB1高表达可明显提高HeLa的细胞生长速度(P＜0.05),HMGB1沉默后HeLa的细胞生长明显受到抑制(P＜0.05).PI 染色流式细胞仪结果显示:HMGB1过表达后,细胞正常增殖周期被加速(P＜0.05);HMGB1沉默后,细胞增殖周期被抑制(P＜0.05).Annexin V-PI双标法流式细胞仪结果显示,HMGB1过表达后,HeLa细胞凋亡率明显下降(P＜0.05);HMGB1沉默后,HeLa细胞凋亡率明显上升(P＜0.05).RT-PCR方法检测不同细胞组Caspase-3和bcl-2 mRNA的表达,结果显示:HMGB1基因沉默后,Caspase-3 mRNA的表达明显增加(P＜0.05),bcl-2 mRNA的表达明显减少(P＜0.05).Western blot结果显示:HMGB1 基因沉默后,细胞色素C和Caspase-3蛋白表达水平增加,bcl-2蛋白表达水平减少(P＜0.05).结论 HMGB1可提高HeLa细胞生长速度、增殖周期,抑制HeLa细胞凋亡.HMGB1基因沉默可抑制Hela细胞增殖,促进其凋亡.影响Caspase-3—细胞色素C途径及调节bcl-2的表达可能是其主要作用机制.