Responses of antioxidant systems in the hepatocytes of common carp (Cyprinus carpio L.) to the toxicity of microcystin-LR.

The freshwater, bloom-forming cyanobacterium (blue-green alga) Microcystis aeruginosa produces a peptide hepatotoxin, which causes the damage of animal liver. Recently, toxic Microcystis blooms frequently occur in the eutrophic Dianchi Lake (300 km2 and located in the South-Western of China). Microcystin-LR from Microcystis in Dianchi was isolated and purified by high performance liquid chromatography (HPLC) and its toxicity to mouse and fish liver was studied (Li et al., 2001). In this study, six biochemical parameters (reactive oxygen species, glutathione, superoxide dismutase, catalase, glutathione peroxide and glutathione S-transferase) were determined in common carp hepatocytes when the cells were exposed to 10 microg microcystin-LR per litre. The results showed that reactive oxygen species (ROS) contents increased by more than one-time compared with the control after 6 h exposure to the toxin. In contrast, glutathione (GSH) levels in the hepatocytes exposed to microcystin-LR decreased by 47% compared with the control. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxide (GSH-Px) increased significantly after 6 h exposure to microcystin-LR, but glutathione S-transferase (GST) activity showed no difference from the control. These results suggested that the toxicity of microcystin-LR caused the increase of ROS contents and the depletion of GSH in hepatocytes exposed to the toxin and these changes led to oxidant shock in hepatocytes. Increases of SOD, CAT and GSH-Px activities revealed that these three kinds of antioxidant enzymes might play important roles in eliminating the excessive ROS. This paper also examined the possible toxicity mechanism of microcystin-LR on the fish hepatocytes and the results were similar to those with mouse hepatocytes.     

Optical response of the cultured bovine lens; testing opaque or partially transparent semi-solid/solid common consumer hygiene products

This study determines the relative ocular lens irritancy of 16 common partially transparent or non-transparent consumer hygiene products. The irritancy was found by measuring the changes in the sharpness of focus [referred to as the back vertex distance (BVD) variability] of the cultured bovine lens using a scanning laser In Vitro Assay System. This method consists of a laser beam that scans across the lens, and a computer, which then analyses the average focal length (mm), the BVD variability (mm), and the intensity of the beam transmitted. Lenses were exposed to the 16 hygiene products and the lens’ focusing ability was monitored over 192 h. The products are semi-solids or solids (e.g. gels, lotions, shampoos). They are categorized into six groups: shampoos, body washes, lotions, toothpastes, deodorant, and anti-perspirant. Damage (measured by > 1 mm BVD variability) occurred slower for the shampoos, especially in the case of baby shampoo. The results indicate that shampoos exhibit the lowest level of ocular lens toxicity (irritability) while the deodorant is the most damaging.     

聚甲基丙烯酸酯纳米粒作为反义寡核苷酸传递系统的研究聚甲基丙烯酸酯纳米粒作为反义寡核苷酸传递系统的研究

目的 研究聚甲基丙烯酸酯阳离子纳米粒作为反义寡核苷酸传递系统的可行性。方法 以Eudragit RL100和RS100为材料,采用溶剂-非溶剂法制备纳米粒,再与寡核苷酸混合即得载药纳米粒。用透射电镜观察其形态、粒径测定仪测定粒径、超滤法测定药物的包封率,通过台盼蓝拒染试验和红细胞溶血试验测定纳米粒的细胞毒性,用流式细胞仪测定荧光标记的寡核苷酸的入胞量。结果 纳米粒的形态规整、大小均匀,平均粒径为127 nm左右,几乎所有的药物被负载。使用聚甲基丙烯酸酯纳米粒作为反义寡核苷酸载体后,进入细胞内的药物量急剧增加,并有显著的剂量依赖性,但对细胞有轻微的毒性作用。结论 聚甲基丙烯酸酯阳离子纳米粒是一种稳定、高效的反义寡核苷酸传递系统。     

盐酸他克林前体药物的研究盐酸他克林前体药物的研究

目的制备盐酸他克林(THA)的酰化前体药物以提高其透过血脑屏障(BBB)的能力。方法THA和酸酐反应制得N-酰化-THA系列前体药物;考察了前体药物在不同介质中的降解情况,并以N-单丁酰-他克林(BTHA)为模型药物,考察其在小鼠体内的分布和降解情况。结果合成的化合物经¹HNMR,MS和IR鉴定为目标化合物。前体药物在不同介质中均较稳定。与原药相比,前药的脂水分布系数增大。BTHA主要分布于脑、血浆和肝脏中(最高浓度分别为17.572 5,13.140 0和22.827 9 mg·L^-1),在肺和心中的分布浓度很低(最高浓度分别为4.947 5和4.492 5 mg·L^-1)。BTHA在脑内的降解速率较慢,给药12 h后仍有较高浓度(2.415 9 mg·L^-1)。结论N-羧酰-THA系列前体药物提高了THA透过BBB的能力,有望成为脑内定向给药的有效途径。     

特区经济学的理论前提

实行特殊政策和实施特殊管理体制是世界经济特区共有的基本特征。正是这两个基本特征构成了特区经济学的两个理论前提。对经济特区实行特殊政策和实施特殊管理体制进行理论分析 ,目的在于为构筑特区经济学的理论体系作理论上的准备     

论环境安全视角下的我国灾害防治法制建设

当今社会正面临日趋严重且类型众多的灾害 ,构成生态环境安全的巨大威胁 ;各国大都注意发挥法制手段在灾害防治中不可替代的作用 ;我国系多灾国家 ,在减灾法治方面虽取得一定成就 ,但总体上还比较薄弱 ,加强该领域的法制建设有其必然性与重要意义 ;从我国环境安全保障角度及国际经验的比较来看 ,完善我国减灾法制建设的基本工作 ,涉及到减灾法制体系的理论研究、立法模式的选择及充实的方向、行政体制的理顺及执法司法功能的强化诸方面     

2-Methoxyestradiol Inhibits Longitudinal Bone Growth in Normal Female Rats

2-Methoxyestradiol (2-MeO-E₂), a major metabolite of 17β-estradiol, may function as a physiological tumor suppressor and is being investigated for clinical applications. It has been reported to target rapidly dividing cells. We investigated the effects of 2-MeO-E₂ on the growth plate of young rats because normal longitudinal bone growth requires rapid proliferation of cartilage and endothelial cells. Sexually mature (3-month-old) normal female rats were treated with 2-MeO-E₂ (100 mg/kg/day) for 13 days and it was found to have no effect on uterine weight but reduced serum cholesterol. The estrogen metabolite had no effect on either cortical or cancellous bone. In contrast, 2-MeO-E₂ dramatically reduced longitudinal bone growth rate at the proximal tibia from 55 ± 2 to 20 ± 2 μm/day (P < 0.001) and growth plate thickness from 153 ± 14 to 70 ± 6 μm (P < 0.001). The latter decrease was due to significant reductions in the height of both the proliferative (P < 0.001) and the hypertrophic (P < 0.001) zones. These results in normal female rats demonstrate that 2-MeO-E₂ inhibited longitudinal bone growth but had no effect on either radial bone growth or cancellous bone turnover. 2-MeO-E₂ was shown by these studies to have the ability to discriminate between bone and cartilage, as well as between reproductive and nonreproductive estrogen-target tissues. Thus, 2-MeO-E₂ is a naturally produced estrogen metabolite that demonstrates unique tissue selectivity. Received: 21 July 1999 / Accepted: 12 January 2000     

光动力和经皮氩氦系统冷消融联合治疗非小细胞性阻塞性肺癌

目的 研究联合应用光动力疗法和经皮氩氦系统冷消融，对不能切除性非小细胞性阻塞性肺癌的治疗价值。方法 41例非小细胞性阻塞性肺癌患者，或者固为肿瘤局部进展(按TNM分期为Ⅲb期)，或者因为肺功能差(严重阻塞性肺病)，被认为是不能切除性的。先予光动力疗法。静脉注射光敏剂Photofrin 2mg／kg(或血卟啉5mg／kg，华鼎药业)，48和72小时分别在支气管镜下输入630nm红色激光照射；再在B超或CT引导下通过氩氦系统进行经皮冷消融。按症状、肿瘤大小和生存期判断疗效。结果 41例经此种联合疗法治疗后，90．2％的患者主观症状有不同程度改善，症状积分治疗后明显降低，呼吸困难的改善最为明显；支气管镜复查，发现全部惠者支气管内肿瘤均得到不同程度消融，其中41．5％完全消失；CT复查发现肺内肿瘤CR34．1％，PR41．4％；X线片上，原有肺塌陷的病例中29．6％的塌陷完全消失，70．4％的肺塌陷减轻；半年和1年生存率分别达44和71％。无论光动力抑或经皮氩氦系统冷消融，均未发生严重并发症。结论 联合应用光动力疗法和氩氦系统经皮冷消融，能分别消除支气管内、外的病变，两者相辅相成，因而可提高不能切除性非小细胞性阻塞性肺癌的治疗效果。     

组合小片胶囊释放行为的研究及其数学模型嵌合组合小片胶囊释放行为的研究及其数学模型嵌合

目的制备硝苯地平(nifedipine，NP)的速释小片、缓释小片以及不同时滞的脉冲小片和延缓小片，多途径组合实现多次脉冲释药、定位释药、定速释药及快/慢释药系统等。方法采用非线性最小二乘法模型嵌合通用程序求出各小片释药的速率方程，比较4种方案的组合释药理论速率-时间曲线与实测值的差异。结果速率方程较为准确地描述了单片释药行为，速率-时间曲线中各种组合的体外释药实测值与各模拟方程迭加形成的理论曲线较接近，表明组合释药行为是可以理论表征的，因而组合设计可控，组合效应可预估。结论通过加和速率方程可预测由各种小片不同用量、不同组合灌装于胶囊内形成的多种释药行为。     

植物类中药材GAP认证技术体系的探讨

本文对中药材认证的法规和管理体系做了简要说明，对中药材生产过程中的规范化要求及其应开展的主要工作进行了探讨。分析了影响中药材质量的主要生产技术环节及其认证要求。介绍了GAP认证对人员、设备和档案的要求，并对认证准备工作中需要建立的文件、资料和档案系统提出了建议。