载siRNA的纳米制剂研究进展

目的:为小干扰RNA(siRNA)纳米制剂递送的研究提供参考。方法:以"基因治疗""RNA干扰""小干扰RNA""载体系统""siRNA""Gene therapy""RNA interference""Protamine"等为关键词,组合查询1996-2016年在PubMed、中国知网、万方、维普等数据库中的相关文献,对载siRNA的纳米制剂的导入方法、载体类型及影响递送过程的主要因素进行综述。结果:共检索到相关文献500余篇,其中有效文献40篇。载siRNA的纳米制剂导入方法主要分为物理化学法和载体介导法。在载体介导法中的非病毒载体,不仅克服了siRNA半衰期短、生物利用度低等缺点,而且在一定程度上提高了siRNA的递送效率,是现代药剂学研究的一个热点。常用非病毒载体包括阳离子脂质体、二元复合物纳米载体、三元复合物纳米载体。载体靶向性修饰、粒径与表面电荷是递送siRNA纳米载体主要影响因素。siRNA的高效递送依赖于新的高效、低免疫原性载体的开发以及纳米制剂递送系统的优化。因此,可载siRNA的高效、低免疫原性纳米制剂的研究任重而道远。     

siRNA体内递送研究进展

RNA干扰(RNA interference,RNAi),是一种在动植物中存在的通过双链RNA诱导同源特异性序列转录后基因沉默的过程。虽然小干扰RNA (siRNA) 较单链反义寡核苷酸显示出更好的稳定性与基因沉默效果,但是作为新型的基因治疗药物,靶向递送siRNA是药物进入临床应用最主要的环节,siRNA体内有效作用发挥的关键在于它在体内能否高效递送至靶细胞并与靶基因结合。目前研究主要集中在siRNA的修饰方式与递送载体研究,以提高其体内的稳定性与靶向性。文中主要综述了siRNA的体内靶向递送障碍以及近几年siRNA非病毒递送载体脂质体、阳离子多聚物、纳米粒、胶束等方面的研究进展。     

siRNA新型非病毒载体递送策略新进展

小干扰RNA(siRNA)是一个靶向治疗和精确医学的代表性治疗工具，可通过序列特异性的RNA干扰(RNAi)沉默任何疾病相关基因的表达。然而，它的治疗前景历来受到体内半衰期短、递送困难和安全问题的限制。非病毒载体介导的药物递送已经成为克服这些局限性的一个成功策略，可实现siRNA在体内的有效递送，高效沉默靶基因。目前，已有多种药物处于临床试验中，4种基于siRNA的新型疗法已获得美国FDA的批准，标志着靶向疗法新时代的开始。该文概述了近年来基于siRNA的非病毒载体递送策略的新进展及其应用，并展望了siRNA药物研究的未来发展趋势。     

小干扰RNA非病毒递送载体的研究进展

虽然RNA干扰应用在哺乳动物细胞中的时间较短,但siRNA强效抑制靶基因表达的功能使它成为目前广泛研究的一种药物。siRNA作为新型的基因药物可有效治疗多种恶性疾病,比如癌症、病毒性感染疾病、遗传及代谢紊乱性疾病等。siRNA在体内不稳定,易被核酸酶降解,有触发免疫反应的倾向,因此选择安全稳定的载体将其递送到靶组织靶细胞是siRNA在体内发挥作用的前提。非病毒载体低毒、低免疫反应且结构可控,目前已被广泛使用来解决基因递送过程中遇到的困难。文章主要综述了近年来研究广泛的siRNA非病毒递送载体:脂质体、阳离子聚合物、树枝状大分子、无机纳米材料等。     

高分子聚合物用于siRNA递送系统的研究进展

小干扰RNA（siRNA）具有沉默互补的目标信使RNA（mRNA）从而抑制疾病相关基因表达的作用。因其高效性及特异性,siRNA具有作为基因药物的巨大潜力,但其在体内易受到血管屏障、内涵体及RNA酶等因素的影响,从而难以发挥药效。因此,设计高效的能够负载siRNA的纳米载体以使其富集至靶标是目前siRNA药物研发的重要任务,高分子聚合物纳米载体是目前研究热点之一。本文就高分子聚合物纳米载体实现siRNA药物递送的研究进展进行综述。     

小干扰RNA治疗药物载体递送技术研究进展

RNA干扰（RNAi）是一种控制靶基因表达的序列特异性调控机制。体内外研究结果表明,RNAi技术的应用对多种疾病治疗有巨大的前景,其瓶颈在于如何将基于RNAi的药物有效递送至靶细胞或靶组织。常用的载体递送系统可分为病毒载体系统和非病毒载体系统。研究载体递送系统需重点考虑的因素有脱靶效应、递送方式、免疫反应诱导及剂量等。如果这些关键问题能够解决,将大大增加RNAi成为治疗药物的可能性。     

壳聚糖衍生物作为siRNA纳米递送系统材料的研究进展

小干扰RNA(small interfering RNA,siRNA)在治疗疾病方面具有高效性、特异性、瞬时性等优良特性,是目前药物研发关注的焦点。但裸露的siRNA稳定性差、细胞摄取率低,难以发挥其基因沉默作用,因此需要一种优质的递送系统将其递送至靶细胞中,使其发挥作用。大部分纳米递送系统因毒性、载药问题不利于siRNA的转运,而壳聚糖衍生物具有较高的水溶性、安全性、稳定性,已受到广泛关注。本文综述了壳聚糖衍生物应用于siRNA纳米递送系统的研究进展,为正在进行纳米递送系统研究的科研工作者提供参考。     

siRNA分子非病毒纳米传递载体的研究进展

小分子干扰RNA (siRNA)的非病毒纳米传递载体与病毒载体比较,前者具有简便、安全和毒性小等特点,易于为临床所接受,因此近年的研究进展迅速.文中根据最近几年来国内外相关文献,对siRNA非病毒纳米传递载体的研究进行了综述.     

siRNA非病毒递送载体的研究现状

RNA干扰(RNA interference,RNAi)是近年发展起来的一种新技术。RNAi是指通过外源性或内源性的双链RNA在体内诱导靶基因mRNA产生特异性降解,进而引起不同水平的基因沉默。RNAi已经用于肿瘤、病毒感染、乙型肝炎等多种疾病的治疗。小干扰RNA(siRNA)是RNAi的效应分子,可在体内诱导RNAi效应。但是裸siRNA在体内容易被核酶(RNase)降解,且半衰期短,转染效率低。因此,siRNA需要借助递送载体进入细胞发挥治疗作用。病毒载体在基因治疗中有潜在的免疫原性、致突变等副作用。所以,非病毒载体成为当前的研究热点。本文对siRNA非病毒递送载体的研究现状进行了综述。     

非病毒siRNA载体研究进展

研发siRNA类药物成为人类未来药物的主攻方向之一。然而,siRNA自身的不稳定性以及体内复杂的环境限制了siRNA在体内安全有效的递送。因此,siRNA需要借助特定的载体才能发挥生物学效应。该文综述了非病毒类载体在提高siRNA体内递送效率方面的研究进展。     

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.

---

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.