酸敏感响应型纳米药物递送系统在肿瘤治疗中应用的研究进展

癌症是危害人类生命健康的一类重大疾病。肿瘤组织与正常组织相比具有特殊的酸性微环境,利用此特殊性质,研究者设计了一系列具有酸敏感响应性的药物递送载体,用以增强抗肿瘤药物在肿瘤部位的富集、肿瘤组织的渗透和肿瘤细胞的摄取,同时加速药物在靶部位的释放,从而提高肿瘤治疗的效果。本文综述了响应于肿瘤微酸环境的纳米药物递送系统的设计及其在抗肿瘤治疗中的应用。     

基于肿瘤微环境的纳米靶向载体研究进展

目的:为纳米靶向载体研制提供参考。方法:以"肿瘤微环境""纳米靶向载体""靶向治疗""pH sensitive""Enzyme responsive""Redox responsive"等为关键词,组合查询2005-2016年在Pub Med、Elsevier、Springer Link、中国知网、万方、维普等数据库中的相关文献,对肿瘤组织微环境的特点和肿瘤微环境响应性纳米载药系统研究进行综述。结果与结论:共检索到相关文献235篇,其中有效文献39篇。肿瘤组织微环境主要特点包括微酸性、酶代谢异常、细胞内外存在还原性差异、存在影响肿瘤血管生成的因子和信号通路等。基于上述特点,分别研究出基于肿瘤滞留效应设计的纳米载体、pH响应型纳米载体、还原响应型纳米载体、酶响应型纳米载体、温度响应型纳米载体。与这些单响应载体比较,肿瘤微环境多重刺激响应型纳米载体更能充分发挥不同肿瘤微环境响应性物质之间的特点,对实现药物的特异性递送更有意义,这也将是今后的主要研究热点。     

温敏聚合物自组装纳米粒子在抗肿瘤药物递送中的应用

作为抗肿瘤治疗的主要手段,化疗最大的缺陷在于化疗药物缺乏肿瘤靶向性,易对正常组织产生高毒性,并导致治疗效果不理想。为了解决这一问题,越来越多的聚合物纳米载体被用于递送抗肿瘤药物,包括对温度刺激能作出响应的温敏聚合物自组装纳米载体。笔者综述了近年来温敏聚合物自组装载体及其纳米粒子的研究进展,并介绍了其在抗肿瘤药物递送中的应用。     

肿瘤微环境pH响应靶向载体设计研究进展

目的归纳和概括基于肿瘤微环境pH响应载体设计的方法与策略。方法以国内外具有代表性文献34篇为依据,对pH敏感靶向传递系统的设计原理方法进行分析、整理和归纳。结果 pH敏感靶向载体借助于其pH敏感基团对肿瘤微环境做出响应,可以实现药物的定向递送,杀死肿瘤细胞并降低药物对正常组织的毒副作用。结论构建pH敏感载体用作肿瘤的靶向治疗,具有重要的研究意义。     

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。     

抗肿瘤纳米药物的靶向递送及药代动力学模型研究进展

纳米技术兴起为癌症检测和治疗带来了新希望,大量研究已证明增强的肿瘤组织渗透性和滞留效应是纳米抗肿瘤药物发挥药效的关键,但是此效应也会受到体内多种因素的影响而导致纳米药物递送障碍和分布不均。这种递送障碍和分布不均主要是肿瘤血管系统异常和组织间液基质紊乱造成的。详细阐述纳米药物靶向病灶过程中的多重生理病理屏障,总结肿瘤组织微环境正常化调节手段,介绍若干用于描述抗肿瘤药物体内组织递送的生理药代动力学(PBPK)模型,为纳米药物的癌症治疗提供理论参考。     

RNA药物递送研究进展

核糖核酸(ribonucleic acid, RNA)药物可基于碱基互补配对原则,针对目的基因的碱基序列进行设计,精准调控基因表达,干预遗传病、罕见病和肿瘤等多种疾病,具备强大治疗潜力。然而,当前RNA药物在成药性方面仍受到众多因素制约,面临包括稳定性、半衰期、免疫原性、组织靶向性、细胞摄取和内涵体逃逸等多方面的挑战。本文介绍了近年来受到广泛关注的几种RNA药物,主要包括信使核糖核酸(messenger RNA, mRNA)、小干扰核糖核酸(small interfering RNA, siRNA)、小分子核糖核酸(microRNA, miRNA)和反义寡核苷酸(antisense oligonucleotide,ASO),总结了其体内作用机制和面临的挑战,概述了包括化学修饰、配体偶联、纳米载体在内的多种克服RNA体内递送瓶颈的递送策略;从制备及应用等方面,详述了RNA纳米递送载体中的脂质纳米粒、高分子聚合物载体及外泌体。本文旨在为发展高效安全的体内RNA递送技术提供理论依据和设计思路,促进RNA药物临床转化。     

肿瘤微环境调节型细胞器靶向递药系统的研究进展

近年来,利用机体免疫系统进行抗肿瘤的免疫疗法受到了广泛关注。然而抑制性肿瘤微环境限制了免疫治疗的效果,因此克服肿瘤微环境及其中的免疫抑制性细胞的作用成为肿瘤免疫疗法的一大热点。纳米制剂具有重新编程免疫抑制性微环境的巨大潜力,为免疫治疗提供了有效策略。随着主动靶向性纳米载体技术的不断发展和对药物作用位点研究的不断深入,具有更精准主动靶向功能的亚细胞器靶向性纳米载体材料也受到越来越多的关注。本文简要介绍了各亚细胞器与肿瘤的关系,概述了基于酸碱性调节、活性氧含量、免疫原性及免疫抑制细胞的肿瘤微环境特点的纳米药物靶向递送系统的设计策略与研究进展,为亚细胞器途径靶向递药系统的构建及其在肿瘤免疫治疗方面的应用提供借鉴和参考。     

肿瘤微环境响应型纳米凝胶递药系统的研究进展

肿瘤微环境响应型纳米凝胶因其独特的凝胶三维网状结构,同时具备良好的生物相容性、体内循环时间长等特性,使其在纳米药物递送领域受到越来越多的关注。根据不同的肿瘤微环境,主要可分为生物微环境响应型纳米凝胶及物理微环境响应型纳米凝胶2大类。通过对这2大类肿瘤微环境响应型纳米凝胶在药物递送中的研究进展的综述,以期为更精准智能的纳米凝胶递药系统的研发提供参考。     

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。     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

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.     

Lung disease and PKCs

The lung offers a rich opportunity for development of therapeutic strategies focused on isozymes of protein kinase C (PKCs). PKCs are important in many cellular responses in the lung, and existing therapies for pulmonary disorders are inadequate. The lung poses unique challenges as it interfaces with air and blood, contains a pulmonary and systemic circulation, and consists of many cell types. Key structures are bronchial and pulmonary vessels, branching airways, and distal air sacs defined by alveolar walls containing capillaries and interstitial space. The cellular composition of each vessel, airway, and alveolar wall is heterogeneous. Injurious environmental stimuli signal through PKCs and cause a variety of disorders. Edema formation and pulmonary hypertension (PHTN) result from derangements in endothelial, smooth muscle (SM), and/or adventitial fibroblast cell phenotype. Asthma, chronic obstructive pulmonary disease (COPD), and lung cancer are characterized by distinctive pathological changes in airway epithelial, SM, and mucous-generating cells. Acute and chronic pneumonitis and fibrosis occur in the alveolar space and interstitium with type 2 pneumocytes and interstitial fibroblasts/myofibroblasts playing a prominent role. At each site, inflammatory, immune, and vascular progenitor cells contribute to the injury and repair process. Many strategies have been used to investigate PKCs in lung injury. Isolated organ preparations and whole animal studies are powerful approaches especially when genetically engineered mice are used. More analysis of PKC isozymes in normal and diseased human lung tissue and cells is needed to complement this work. Since opposing or counter-regulatory effects of selected PKCs in the same cell or tissue have been found, it may be desirable to target more than one PKC isozyme and potentially in different directions. Because multiple signaling pathways contribute to the key cellular responses important in lung biology, therapeutic strategies targeting PKCs may be more effective if combined with inhibitors of other pathways for additive or synergistic effect. Mechanisms that regulate PKC activity, including phosphorylation and interaction with isozyme-specific binding proteins, are also potential therapeutic targets. Key isotypes of PKC involved in lung pathophysiology are summarized and current and evolving therapeutic approaches to target them are identified.     

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.