Effect of low-dose phenobarbital on hepatic microsomal UDP-glucuronyl transferase activity

To determine whether hepatic microsomal enzyme induction occurs in rats following administration of phenobarbital at doses similar to those used in humans (0.5 to 7.5 mg/kg), UDP-glucuronyl transferase (UDPGT) and cytochrome P-450 activities were measured in liver homogenate and microsomal preparations from control rats and rats treated for 6 days with phenobarbital at 1 and 3 mg per kg per day. While no significant increases in liver weight and protein content of homogenate and microsomal preparations were observed with either dose of the drug, both UDPGT and P-450 activities were enhanced significantly following administration of phenobarbital at 3 mg per kg per day. The activity of P-450 was increased by approximately 30% and that of UDPGT by 15-24 and 45-66%, respectively, employing bilirubin and p-nitrophenol as the acceptor substrate. The extent of induction of bilirubin or p-nitrophenol UDPGT was similar when measured with "native" enzyme or with enzyme activated by UDP-N-acetyl glucosamine, digitonin or deoxycholate. These data suggest that the discordant effects of phenobarbital on UDPGT and cytochrome P-450 previously reported in humans and rats may not be attributable solely to differences in the drug doses employed.     

Phase I evaluation of 773U82-HCl in a two-hour infusion repeated daily for three days

One of a novel series of compounds (AMAPS or arylmethylaminopropanediols), 773U82-HCl has shown significant antitumor activity inin vitro and inin vivo tumor systems, but has less animal CNS toxicity than the lead compound in the same series (crisnatol). This study was designed to evaluate the pharmacokinetics, qualitative and quantitative toxicities of 773U82-HCl and to determine the recommended phase II dose (MTD) of 773U82-HCl given as a short infusion daily for 3 days every 3 weeks. Twenty-nine patients with refractory malignancies received 79 courses over 9 dose levels during this study. Doses ranged from 50 to 1060 mg/m²d×3 days. Due to the possibility of local hemolysis with concentrations > 1.5 mg/ml, drug was administered in solutions containing 1.5 mg/ml. Because large volumes were needed at the higher dose levels, the infusion duration was increased from 2 hours to 4 hours. Mild to moderate nausea, vomiting, fatigue, dizziness and headaches were observed. Myelosuppression was the dose limiting toxicity. The recommended phase II dose and schedule was determined to be 800 mg/m²d×3d every 3 weeks. 773U82-HCl plasma concentration-time data were analyzed using a two-compartment pharmacokinetic model. The t1/2 averaged 6 hours and the total body clearance was 75.9 L/hr/m². The volume of distribution (Vdss) was large, averaging 470 L/m².Abbreviations ECG electrocardiogram - t^1/2 half-life - Vdss volume of distribution - HPLC highperformance liquid chromatography - Vd_ss steady-state volume of distribution - AUC area under the concentration × time curve - CL total body clearance - C_max peak plasma level - V_c central volume of distribution     

人单核巨噬细胞泡沫化抑制剂筛选模型的建立及应用

目的: 建立人单核巨噬细胞泡沫化抑制剂筛选模型,筛选得到可抑制细胞泡沫化的抑制剂.方法: U937单核细胞经100 nmol·L-1佛波酯(PMA)诱导72 h分化为巨噬细胞后,换无血清培养液于96孔板中,每毫升含巨噬细胞1×106个,每孔再加入80 mg·L-1氧化的低密度脂蛋白(ox-LDL),37 ℃培养48 h,建立单核巨噬细胞泡沫化模型.利用微生物发酵液,或单一的化合物样品与其共孵育,油红.染色后观察细胞胞内变化,寻找对泡沫细胞形成有抑制作用的样品.利用基因工程技术表达的人清道夫受体A类II型的胞外部分,在本模型中可抑制巨噬细胞泡沫化的形成,进一步验证了模型的可行性.结果: 从2000 个微生物发酵液中筛选到6株微生物发酵液为阳性,从10个化合物中发现一个有抑制巨噬细胞泡沫化活性的新化合物.结论: 本模型可用于细胞泡沫化抑制剂的高通量筛选.     

κ-阿片受体与β1-肾上腺素受体交互作用抑制异丙肾上腺素诱导的心肌肥大

目的:观察选择性kappa阿片受体(kappaopioidreceptor,κOR)与β肾上腺素受体(βadrenergicreceptor,βAR)在心肌细胞肥大方面的交互作用。方法:以体外培养的乳鼠心肌细胞为模型,10μmol·L-1的异丙肾上腺素(β肾上腺素受体激动剂,βAR)诱导心肌肥大,观察1μmol·L-1的U50,488H(κOR激动剂,U50)对其作用。进一步探索在100nmol·L-1ICI118,551(β2AR阻断剂)存在情况下,κOR的激活对心肌肥大的作用。用Lowry’s法测心肌细胞的蛋白质含量;用消化分离法,并利用计算机图象分析系统测心肌细胞的体积;用[3H]leucine掺入法测定心肌细胞蛋白的合成。结果:异丙肾上腺素使心肌细胞总蛋白含量、体积、蛋白合成明显增加;1μmol·L-1的U50,488H使ISO诱导的心肌细胞总蛋白含量、体积、蛋白合成减少,这种作用可被选择性κOR阻断剂norBNI(norbinaltorphimine)抑制。在ICI118,551存在的情况下,U50也能起到减弱ISO诱导心肌细胞肥大的作用。结论:U50,488H通过激活κOR与β1AR交互作用抑制ISO所诱导的心肌细胞肥大。     

分子信标PCR检测脲原体U.Parvum和U.Urealyticum

目的 建立2个快速、同步检测脲原体U．Parvum和U．Urealyticum的分子信标PCR反应体系。方法 依据脲原体尿素酶B基因序列，设计分别针对U．Parvum和U．Urealyticum的特异性分子信标探针及引物，建立2个分子信标PCR反应体系。通过对脲原体标准株扩增后荧光强度的检测、分子信标S／B值测定以及进行特异性和敏感性实验，对2个体系进行评价并设定2个分子信标PCR反应体系的cutoff值。结果 U．Parvum和U．Urealyticum的分子信标S／B值均〉20。2个分子信标PCR体系能够检测U．Parvum、U．Urcalyticum标准株DNA．与其他14株细菌（包括5株有尿素酶细菌）无交叉反应，检测限度均为10拷贝／μl的重组质粒DNA。U．Parvum分子信标PCR反应体系的cutoff值为3．89．U．Urealyticum分子信标PCR反应体系的cutoff为5．32。结论 2个分子信标PCR反应体系能够快速、同步进行脲原体的分种鉴别，具有高度特异性和灵敏性。     

Neuromedin U及其受体的研究进展

NeuromedinU作为一种脑肠多肽 ,其外周生物活性包括刺激平滑肌、增加血压、增加血流、改变小肠离子传输、控制局部血流、调节肾上腺皮质素等功能 ,已发现neuromedinU在中枢神经系统的作用为减少食物摄取和体重。该文就neuromedinU及其受体的结构、组织分布和生理学功能等研究进行综述。     

寡核苷酸表达谱揭示异烟肼耐药对结核分支杆菌致病性的影响

目的研究结核分支杆菌异烟肼耐药菌株与H37Rv异烟肼敏感菌株感染巨噬细胞后差异表达的基因. 方法利用高密度cDNA芯片检测巨噬细胞U937感染结核分支杆菌异烟肼耐药菌株与H37Rv后的基因表达谱的差异. 结果两者诱导巨噬细胞的差异表达基因有53条,异烟肼耐药菌株比敏感菌株诱导多种趋化因子和细胞免疫增强的细胞因子表达上调和免疫抑制细胞因子IL-10等表达下调. 结论异烟肼耐药对细菌毒力有明显的影响,异烟肼耐药菌株的致病力下降,异烟肼耐药菌株容易被宿主免疫系统清除;结果为耐多药结核病控制提供依据;骨桥接素和巨噬细胞趋化因子等,在抗异烟肼耐药结核分支杆菌感染免疫中的作用值得深入研究.     

白藜芦醇通过下调CD44表达抑制胶质瘤U251细胞增殖和侵袭

目的 探讨白藜芦醇对脑胶质瘤细胞增殖和侵袭的影响及可能的分子调控机制。方法 体外培养胶质瘤U251细胞,分别用浓度为0μmol/L、50μmol/L、100μmol/L、150μmol/L白藜芦醇继续培养48 h,参考Lipofectamine2000TM说明书将pcDNA3.1/CD44(CD44过表达)、pcDNA3.1（过表达对照）等质粒转染胶质瘤U251细胞并培养24 h进行后续实验。利用CCK-8法检测细胞增殖,利用Transwell实验检测细胞侵袭;RT-PCR和免疫印迹法检测细胞CD44、CyclinD1、CDK4、MMP2和MMP9的mRNA和蛋白表达。结果 白藜芦醇明显抑制U251细胞的增殖和侵袭能力（P<0.05）,而且呈浓度依赖性（P<0.05）;所以,用150μmol/L白藜芦醇进行CD44干预实验。白藜芦醇明显抑制U251细胞CD44、CyclinD1、CDK4、MMP2和MMP9的mRNA和蛋白表达（P<0.05）,而且呈浓度依赖性（P<0.05）。CD44过表达明显抑制白藜芦醇对胶质瘤U251细胞增殖和侵袭的抑制作用（P<0....     

桑黄总三萜的提取及其体外抗脑胶质瘤U251活性

目的:优化药用真菌桑黄总三萜的超声提取工艺并测定其对脑胶质瘤U251生长的抑制作用.方法:采用正交设计试验对超声辅助提取过程中影响桑黄总三萜得率的乙醇体积分数、超声时间、超声温度和料液比等因素进行优化;采用MTT比色法测定桑黄总三萜对U251细胞株增殖的抑制率,应用倒置相差显微镜观察桑黄总三萜对肿瘤细胞形态结构的影响.结果:超声辅助提取桑黄总三萜的最佳工艺条件为70％乙醇,超声提取20 min,温度60℃,料液比1∶25.在此条件下,桑黄总三萜提取率可达9.40 mg·g-1.桑黄总三萜对脑胶质瘤U251细胞株有抑制增殖作用,且表现出浓度依赖关系,倒置相差显微镜下可见部分细胞形成凋亡小体.结论:采用超声辅助提取桑黄总三萜时间短、得率高,是一种高效、快捷的方法,桑黄总三萜可抑制脑胶质瘤U251细胞株的增殖,诱导肿瘤细胞凋亡.