溴氰菊酯对脂质体流动性影响的质子核磁共振研究

本文用质子核磁共振(~1H NMR)技术研究了溴氰菊醋对二豆蔻酰磷脂酰胆碱(DMPC)、二棕榈酰磷脂酰胆碱(DPPC)和二硬脂酰磷脂酯胆碱(DSPC)脂质体流动性的影响。结果表明,溴氰菊酯增加这三种脂质体的流动性。     

维生素B_(12)脂质体的制备及体外释放

由于抗恶性贫血药维生素B_(12)是在肝脏中贮藏,而脂质体具有靶器官定向作用的独特优点,因而设想以脂质体给药可以减少剂量并收到较好的效果。用维生素B_(12)盐酸盐分别与合成类脂L-α二棕榈酰磷脂酰胆碱(DPPC)和L-α二肉豆蔻酰磷脂酰胆碱(DMPC)制成脂质体,制备时或加进磷酸二鲸蜡酯或硬脂酰胺使脂质体带上负电或正电荷。具体制法是将10~(-4)M类脂,其中包括10%(克分子百分比)荷电物质置于圆底烧瓶内,以25ml氯仿溶解,在旋转蒸发器上于48°真空蒸发至呈干燥薄层。然后加进含50mgB_(12)、pH为7.0的0.01M磷酸盐缓冲液25ml,缓缓搅动,形成B_(12)的多层脂质体。将混悬液于4～6°放置96小时以保证类脂充分水合,离心后分散于磷酸盐缓冲液中,再经离心即得。     

新型阿霉素热敏脂质体的研制

目的:探讨以二棕榈酰磷脂酰胆碱(DPPC)和单棕榈酰磷脂酰胆碱(MPPC)为原料制备的温度敏感阿霉素脂质体的制备工艺和理化性质.方法:采用膜过滤挤压法和pH梯度法制备阿霉素脂质体,以紫外分光光度法检测样本中阿霉素含量,计算阿霉素热敏脂质体在不同温度下的药物释放特性,并对其包裹率、粒径,pH值进行研究.结果:阿霉素热敏脂质体在39℃下迅速释放,前20 s内释放药物50%,42℃下药物释放达到60%以上.包封率99.5%,平均粒径90.8 nm,pH值为6.5.结论:制备的热敏感阿霉素脂质体优于常规脂质体,具有良好的温度控释特性.     

正交试验优化硫酸长春新碱脂质体的制备工艺

目的制备性质稳定的硫酸长春新碱脂质体。方法采用单因素试验考察磷脂与胆固醇比例、药脂比、脂质浓度、载药温度、载药时间、外水相p H值对硫酸长春新碱脂质体包封率的影响。以包封率为指标,分别以氢化磷脂(SPC-3)和二硬脂酰磷脂酰胆碱(DSPC)为磷脂材料,通过正交试验考察载药温度、药脂比和载药时间对制备工艺的影响,优化出硫酸长春新碱脂质体的最佳制备工艺。结果硫酸长春新碱脂质体的最佳制备工艺为:将药物溶液(按照药物含量计)和空白脂质体溶液(按照脂质含量计)按照1∶20的比例混合,用Na2HPO4直接调节外水相p H值至7.2。SPC-3脂质体在65℃条件下载药,载药时间30 min。DSPC脂质体在60℃条件下载药,载药时间10 min。结论优选出的硫酸长春新碱脂质体的处方工艺稳定可行。     

高效液相色谱-电雾检测法测定两性霉素B脂质体中磷脂含量

目的：考察不同条件下两性霉素B脂质体中磷脂二硬酯酰磷脂酰甘油（DSPG）及氢化大豆磷脂酰胆碱（HSPC）的稳定性。方法：利用HPLGCAD法测定脂质体磷脂膜中各种类脂的含量，采用G色谱柱，流动相为甲醇-水，梯度洗脱，流速1．0mL·min^-1结果：DSPG，HSPC的平均回收率分别为100．01％，100．02％，RSD分别为0．56％，0．41％；DSPG，HSPC的日内精密度分别为0．14％，0．04％。4℃放置3个月HSPC含量均高于80％，DSPG含量均高于90％。结论：HPLC-CAD联合应用可以快速、高效、准确地检测脂质体中的磷脂及其降解产物的含量，制备的两性霉素B脂质体在4℃条件下具有较高的稳定性。     

人工外泌体共递送siRNA和蛋白的递送系统的设计及体外评价

本文制备了人工外泌体,共传递蛋白和核酸,实现多组分药物高效安全共传递。采用阳离子脂质赋形剂二油酰基三甲基铵丙烷(dioleyl trimethylammonium propane, DOTAP)修饰聚乳酸-羟基乙酸共聚物(polylactic acidglycolic acid copolymer, PLGA)基质来设计优化的制剂,双乳化法制备包裹蛋白和核酸的PLGA/DOTAP纳米粒,再用逆相蒸发法制备最外层的膜结构,此膜结构由二棕榈酰磷脂酰胆碱(1, 2-dipalmitoyl-sn-glycero-3-phosphocholine,DPPC)、二油酰磷脂酰胆碱(1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC)、二硬脂酰磷脂酰胆碱(1,2-distearoylsn-glycero-3-phosphocholine, DSPC)、胆固醇及膜蛋白组成,通过超声分散和挤出的方式形成人工外泌体结构,并分析其物理特性和传递效果性质。结果表明,人工外泌体粒径约为156.13 nm,带负电荷(-18.23±0.57 mV),能高效共传递蛋白和siRN...     

从脂质体两性霉素B中分离两性霉素B的固相萃取法

两性霉素B是重要的抗霉菌抗生素,为了减少其毒性,现采用与磷脂(二肉豆蔻酰磷脂酰胆碱DMPC和二肉豆蔻酰磷脂酰甘油DMPG)结合成脂质体两性霉素B。脂质体两性霉素B制剂含有5mg/ml两性霉素B和6.5mg/ml类脂体(7ml DMPC和3 mlDMPG)于生理盐水中。由于类脂体的干扰使微生物法测定两性霉素B效价结果偏低,因此在测定前需将类脂体预先分离除去,常规的萃取方法分离类脂体的效果不佳,从TLC实验表明,硅胶板用氯仿:甲醇:丙酮:水:氨水(65∶30∶5∶2∶2)展开时二个类脂体和药物之间的迁移行为有较大差别,提示可用硅胶     

6-羧基荧光素脂质体的肺吸收

本文通过测定荧光标记6-羧基荧光素(CF),比较包裹在中性双肉豆蔻酰磷脂酰胆碱(DMPC)/胆固醇(分子比1∶1)和负电荷DMPC/胆固醇/联十六烷基磷酸酯(DCP)(分子比1∶1∶0.2)脂质体中水相标记物的肺生物利用度。脂质体采用薄膜法制备,以0.25mol/L CF水溶液水化,再用超声波将多层脂质体分散制成以上两种脂质体,用凝胶层析和超滤除去未包裹的CF,平均粒径分别     

鬼臼毒素二棕榈酰磷胆碱脂质体治疗尖锐湿疣的临床研究

目的评价0.5%鬼臼毒素二棕榈酰磷脂酰胆碱(DPPC)脂质体治疗尖锐湿疣的临床效果和安全性。方法73例尖锐湿疣患者随机分为两组,治疗组(51例)用0.5%鬼臼毒素DPPC脂质体,对照组(58例)用0.5%鬼臼毒素酊剂。两组给药途径为外用,疗程7～21d。结果0.5%鬼臼毒素DPPC脂质体与0.5%鬼臼毒素酊剂治疗尖锐湿疣的治愈率分别为90.20%和91.38%,无显著性差异(P>0.05)。但治疗组不良反应和复发率明显低于对照组(P<0.05)。结论0.5%鬼臼毒素DPPC脂质体与0.5%鬼臼毒素酊剂具有相似的疗效,但其安全性高,复发率低。     

磷脂组成对包裹蛋白和多肽抗原脂质体抗体应答的影响

作者对皮下注射由双棕榈酰磷脂酰胆碱(DPPC)/双豆蔻酰磷脂酰甘油(DMPG)、DP-PC/双棕榈酰磷脂酰乙醇胺(DPPE)、DPPC/磷脂酰丝氨酸(PS)配制的、含牛血清白蛋白(BSA)、鼠单克隆抗体(McAb)GK1.5或21肽[来自于人类免疫缺陷症病毒(HIV)gp12O第二保守区的第254-274位氨基酸]的脂质体诱生抗体的能力进行了研究,同时也观察了口服含重组曼氏血吸虫28kDa谷胱甘肽-S-转移酶(Sm28GST)的上述脂质体诱生分泌性IgA(sIgA)、IgE和IgG的情况,并与明矾(Alum)和胞壁酰二肽(MDP)佐剂作对照.作者将雌性CD_1小鼠分成5组,分别于0、14天皮下免疫(1)抗原(Ag,5μg);(2)Alum/Ag(lmg/5μg);(3)MDP/Ag(50μg/     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.