凝胶剂中脂溶性茶多酚的含量测定

目的:建立凝胶剂中脂溶性茶多酚的含量测定方法,为制定脂溶性茶多酚凝胶剂质量控制标准提供依据。方法:以无水乙醇为提取溶剂,酒石酸亚铁为显色剂,采用比色法,在540 nm处测定含量。结果:脂溶性茶多酚在0～250 mg.(100 mL)-1浓度范围内线性关系良好(R2=0.9991),平均回收率为102.80%,相对标准偏差为0.93%(n=9)。结论:本法简单、精确、重复性好,可用于凝胶剂中脂溶性茶多酚的含量测定。

Enhanced Sporicidal Activity of Alcohol and Epigallocatechin-Palmitate-Based Hand Hygiene Formulations Comprised of Plant-Derived Compounds

Pathogenic spore-forming bacteria pose high risks to healthcare settings, as well as in the food and beverage industries. We reported recently that novel alcohol-based formulations containing plant-derived compounds, including epigallocatechin-3-gallate-palmitate (EGCG-P), a green tea polyphenol ester, provide > 99.99% inactivation of bacterial spores within 60 sec. Based on recently published data from our group and others, we hypothesize that a combination of EGCG-P and alcohol formulated with other plant-derived ingredients would achieve high sporicidal efficacy against a wide spectrum of bacterial spores and can provide novel hand hygiene methods against bacterial spores without toxicity. The objectives of the current study were to optimize two novel formulations with combinations of glycerol, citric acid, and EGCG-P to increase sporicidal activity and explore the rapid inactivation mechanisms and suitability for sporicidal products with broad-spectrum activities against aerobic and anaerobic bacterial spores. Methods included suspension testing of two formulations against spores from Bacillus cereus and Clostridium sporogenes, quantification of spore germination, and scanning electron microscopy. The results demonstrated that these novel formulations were able to reduce spore germination by >99.999% after 30 sec exposure in suspension tests, and rapidly caused physical damage to the spores. Additional studies are warranted to determine the suitability of the novel formulations for future hand hygiene use.

EGCG对日本血吸虫感染小鼠TIMP-1及α-SMA表达和肝纤维化的影响

目的观察表没食子儿茶素没食子酸酯(EGCG)对日本血吸虫感染小鼠干扰素-γ(IFN-γ)、白介素-13(IL-13)、金属蛋白酶组织抑制因子-1(TIMP-1)及α-平滑肌肌动蛋白(α-SMA)表达的影响,探讨EGCG抑制小鼠日本血吸虫病肝纤维化的作用及机制。方法随机将小鼠分为感染组及对照组(A组)。感染组小鼠用腹部贴片法感染日本血吸虫尾蚴(30±5)条/只后,随机分为感染模型组(B组)、EGCG治疗高剂量[400mg/(kg·d)]组(C组)、治疗低剂量[40mg/(kg·d)]组(D组)、高剂量佐吡喹酮治疗组(E组)、低剂量佐吡喹酮治疗组(F组),溶剂+吡喹酮对照组(G组),灌胃溶剂对照组(H组),每组10只。在血吸虫尾蚴攻击感染后第28d,用EGCG对应灌胃治疗,1次/d,连续治疗8周。其中E、F、G组在感染后第42、43d加用吡喹酮[500mg/(kg·d)]灌胃。实验结束后处死小鼠,测算肝体指数。留取肝脏组织和血清,采用ELISA法测定血清中IFN-γ、IL-13及TIMP-1含量,采用苏木素-伊红(HE)和Masson胶原纤维染色观察小鼠肝组织变性、虫卵肉芽肿与胶原沉积等病理改变,采用免疫组化法观察肝组织中α-SMA的表达。结果与对照组相比,各实验组小鼠肝体指数均升高,肝脏有虫卵肉芽肿形成、胶原沉积及肝纤维化,血清中IL-13、TIMP-1含量升高(P<0.05),肝细胞内α-SMA表达升高(P<0.05)。与感染模型组相比,EGCG高、低剂量治疗组及其佐吡喹酮组IL-13和TIMP-1含量及肝体指数均显著降低(P<0.05),虫卵肉芽肿面积减小,胶原沉积减轻。结论 EGCG可抑制α-SMA表达及TIMP-1分泌,其抗纤维化机制与抑制肝星状细胞(HSC)活化相关,EGCG与吡喹酮伍用可增强其抗血吸虫病肝纤维化作用。

表没食子儿茶素没食子酸酯(EGCG)体外抗日本血吸虫尾蚴作用的研究

目的观察表没食子儿茶素-3-没食子酸酯(Epigallocatechin-3-gallate,EGCG)对日本血吸虫尾蚴的体外杀伤作用及其超微组织结构的变化,探讨EGCG预防日本血吸虫尾蚴感染的效果,为进一步开展血吸虫尾蚴感染预防措施的研究提供实验数据。方法将日本血吸虫尾蚴分别置于空白对照组蒸馏水、药物处理组0.2%EGCG和1%EGCG溶液中,各处理0、30和60min,解剖镜下观察并摄像;分别选取以上3组处理30min的尾蚴进行扫描电镜观察。设置蒸馏水对照组、0.1%和1%EGCG溶液处理30min组尾蚴感染小白鼠,饲养43d后解剖小鼠,冲虫,观察感染情况。结果解剖镜下观察,蒸馏水对照组在0min和30min时尾蚴体态柔和,自由运动;60min时尾蚴虫体完整,蜷缩成团,活动停止。0.2%和1%EGCG处理组在30min时尾蚴剧烈运动,尾部急剧摆动、挛缩,体部发生变形,且1%EGCG处理组比0.2%EGCG处理组尾蚴运动更为剧烈,形态变形更明显;60min时,两组尾蚴尾部都已脱落且死亡。扫描电镜观察对照组尾蚴形态修长且虫体完整,口吸盘、头器和腹吸盘的结构正常,体部与尾部连接紧密,尾蚴体被表面光滑,体棘遍布全身,且头部和躯干部体棘的排列和棘的尖端都朝向身体后方。0.2%和1%EGCG处理30min组尾蚴体部高度收缩且皱褶不平,尾蚴口吸盘变形、肿大,腹吸盘肿胀、变窄,其中1%EGCG处理组比0.2%EGCG处理组尾蚴体部的收缩皱褶和腹吸盘变形更明显;两组EGCG处理组尾蚴体部与尾部连接松弛,尾端呈皱褶状变化,其中1%EGCG处理30min组尾蚴的尾部都已脱落,体表体棘散在分布,体棘紊乱、朝向不一,部分体棘脱落。动物感染试验显示对照组和0.1%EGCG处理组尾蚴感染小鼠的感染率均为100%,但0.1%EGCG处理组的减虫率为33.52%;1%EGCG处理组尾蚴感染小鼠的感染率为16.7%,减虫率81.87%。结论 EGCG对日本血吸虫尾蚴具有体外杀伤作用,发生的形态结构可能影响其侵袭宿主皮肤的能力。

茶多酚硬脂酸酯凝胶剂对银屑病动物模型的作用

目的研究茶多酚硬脂酸酯凝胶剂治疗银屑病的药效学。方法采用普萘洛尔诱发小鼠银屑病模型、小鼠尾部鳞片表皮颗粒层形成模型、磷酸组胺致豚鼠瘙痒模型、低分子右旋糖酐-40致小鼠瘙痒模型,研究茶多酚硬脂酸酯凝胶剂对上述银屑病动物模型的作用。结果茶多酚硬脂酸酯凝胶剂具有抑制普萘洛尔诱发小鼠银屑病模型表皮增生过快和异常角化、促进小鼠尾部鳞片表皮颗粒层形成、止痒等作用,与阴性凝胶剂对照组比较,差异有显著性。结论茶多酚硬脂酸酯凝胶剂对银屑病具有较好的治疗作用,开发应用前景良好。

The nature of friction: A critical assessment

Friction is an essential part of human experience.We need traction to walk,stand,work,and drive.At the same time,we need energy to overcome the resistance to motion,hence,too much friction costs excess energy to perform work,introducing inefficiencies.In the 21st century,we are facing the dual challenges of energy shortage and global warming from burning fossil fuels.Therefore,the ability to control friction has become a top priority in our world today.Yet our understanding of the fundamental nature of friction is still lacking.Friction has always been a subject of curiosity.Intensive study of the origin of friction began in the 16th century,after the pioneering work by Leonardo da Vinci.Yet progress in understanding the nature of friction has been slow,hampered by the lack of instrument to measure friction precisely.Ingenious experiments performed by Amontons,Coulomb,and others have yielded important insights to build the foundation of our understanding.Beginning in the late 1800s and early 1900s,the advent of steam engines,locomotives,followed by the automobiles airplanes,and space exploration demands a clear understanding of friction and the ability to control it for the machinery to last.Significant progress on how to apply and control friction in engineering friction was made through trial and error.At the beginning of the 21st century,a new dimension of nanoscale friction came into the picture in conjunction with the arrival of nanotechnology.Our understanding of atomic and molecular friction has been expanding rapidly.However,integration of the new found knowledge of nanofriction into engineering practices has been elusive.Why?What is the scaling relationship between atomic friction and macro-friction?Is it possible to predict friction at the macro-level from nanoscale results?Why nanofriction values often do not agree with the macrofriction values given the same materials pair?Could it be there is a length scale dependent characteristic friction value?In engineering practice,progress since the 1980s has been slow.Most of the effort has been focused on lubrication research such as elastohydrodynamic theories and solid lubricants.Friction mechanisms and failures have received relative little attention while nanofriction received much of the attention.Today,energy efficiency and renewable energy generation demand our immediate attention while we seek reduction in carbon emission.The ability to control friction becomes an essential step in seeking sustainable technologies.Friction,after all,is an indicator of energy efficiency.If we can reduce the unnecessary parasitic energy losses and increase our current energy efficiency,it will give us time to develop alternative energy sources.This paper examines our current understanding of friction,filling some voids with experimental data,and attempts to integrate the various pieces to identify the gaps of our knowledge,hopefully to spark new avenues of investigations into this important area.