喜树碱与胰蛋白酶的相互作用

喜树碱(camptothecin,CPT)是从珙桐科乔木喜树中分离得到的一类重要抗癌药物,对动物肿瘤及白血病均有明显的抑制作用[1]。CPT分子为五环结构,含有一个吡咯[3,4-b]喹啉环,一个共轭吡啶环和一个α-羟基六元内脂环[2]。CPT通过嵌合抑制DNA拓扑异构酶Ⅰ的活性,对卵巢癌、结肠直肠癌     

4-磺酸基杯芳烃[6]对喜树碱的包合作用

采用荧光光谱研究了抗癌药物喜树碱(CPT)与4-磺酸基杯芳烃[6](SCX6)间的相互作用,结果表明二者形成了1∶1的包合物.通过计算测得包合物的结合常数和二者形成过程的热力学参数,主体分子和离子型客体之间除了通常的疏水作用力还有额外的静电作用力.包合物的形成提高了喜树碱的溶解度并保护了活性内酯环结构.     

喜树碱功能化修饰及抗肿瘤活性研究进展

喜树碱是一种重要的天然产物,具有很强的抗肿瘤活性。然而,喜树碱存在水溶性差、在生理条件下易水解而转为无活性的喜树碱羧酸盐等缺陷,限制了其通过静脉注射的临床应用。而对喜树碱的喹啉环、α-羟基内酯环进行功能化修饰可克服上述缺陷。本文就喜树碱结构的功能化修饰及其抗肿瘤活性进行了综述,以期为其他研究人员更快地开发出具有高效、低毒的新型喜树碱类抗癌药物提供参考。     

20(S)-O-喜树碱肉桂酸酯衍生物的合成及其抗肿瘤活性研究

为了提高喜树碱内酯环的稳定性降低其毒性, 增加其抗肿瘤效能, 以喜树碱为先导化合物, 通过酯化反应直接合成了17个20(S)-喜树碱肉桂酸酯衍生物, 并采用MTT法测定了对于人胃癌细胞SGC-7901的体外抗肿瘤活性, 活性测试结果表明有些化合物的抑制活性明显高于母体化合物喜树碱.     

抗癌活性喜树碱及其药用衍生物的化学合成

<正>喜树碱是由Wall等人[1]从我国引种的药用植物喜树中分离得到的具有五元并环结构的生物碱,具有广谱且优良的抗癌活性,是拓扑异构酶I的选择性抑制剂。目前用于临床治疗     

5-位烷基化取代的喜树碱衍生物的合成和抗肿瘤活性研究

喜树碱(Camptothecin,CPT)是美国化学家Wall和Wani在1966年首先从中国珙桐科植物喜树(Camptothecaacuminata)中提取出来的一种生物碱.试验表明它对许多实体瘤有抗肿瘤活性.药物学家对喜树碱分子的结构修饰,大多数集中在喜树碱的A,B和E环上.喜树碱的C环上5-位取代往往降低活性.我们在制备喜树碱烷基化衍生物过程中发现,喜树碱及其衍生物在碳酸钾和活泼溴代烷作用下得到5-位烷基化产物,用不同的溴代烷分别得到单取代或双取代产物.我们合成的5-位烷基化的喜树碱衍生物经过人肿瘤细胞(KB,KB/VCR,A549,HCT-8,Bel7402,A2780)的体外筛选实验,表明这一类化合物细胞毒性显著降低甚至丧失,这可能是因为取代基的空间位阻作用影响了D环羰基和受体的结合.     

喜树碱及其衍生物的聚乙二醇化学修饰药物研究进展

目的：喜树碱及其衍生物药物是一类重要的抗肿瘤药物,但其存在水溶性差、生物利用度低、毒副作用大等问题,喜树碱及其衍生物的聚乙二醇化学修饰具有十分诱人的前景,但目前国内研究较少,本文综述近年来喜树碱及其衍生物药物的聚乙二醇化学修饰研究进展。方法：以喜树碱（Camptothecin, CPT）、伊立替康（Irinotecan, CPT-11）、7-乙基-10-羟基喜树碱（7-ethyl-10-hydroxycamptothecin, SN38）、聚乙二醇（Polyethylene glycol, PEG）、聚乙二醇化喜树碱（PEG-CPT）等为关键词,查阅近几年国内外相关研究文献。结果与结论：综述了喜树碱及其衍生物的聚乙二醇化学修饰药物的研究进展与临床研究报道,为发掘结构明确、组成稳定的新型化学修饰药物提供理论基础和技术支撑。     

树脂吸附层析法分离喜树果中的喜果甙

自 1 96 6年 Wall等 [1] 首次从喜树植物中分离出喜树碱后 ,至今已有 2 0多种化学成分从中分离出来 ,包括喜树碱 (Camptothecine,CPT)、 1 0 -羟基喜树碱、 1 1 -羟基喜树碱、 1 0 -甲氧基喜树碱、喜树次碱、白桦脂酸及喜果甙 (Vincoside- lactam,VCS- LT)等 [2 ] .研究表明 ,喜树碱类化合物和喜果甙均具有抗癌活性 [3～ 5] .从喜树果中分离喜果甙对充分利用我国丰富的喜树资源具有重要意义 .目前文献报道的分离提取喜果甙方法主要是溶剂萃取和氧化铝柱层析法 [6] ,过程复杂 ,收率很低 .本文采用树脂吸附法对喜果甙进行分离纯化 ,再经…     

喜树碱结构与活性的关系

喜树碱是从我国特有植物喜树中分离得到的。它是一种广谱抗癌药物，对多种肿瘤有疗效，但同时也有副作用。为了寻找一种既具抗癌活性，毒性又小的喜树碱类似物，国外学者对喜树的五个环分别进行了修饰，并对修饰产物进行了药理研究，找到了抗癌活性与结构之间的关系。本文着重介绍他们的研究结果并简要总结一下喜树碱的结构、性质。     

喜树碱衍生物的合成研究进展

目前有不少关于对喜树碱分子结构改进和修饰的报道，许多高活性的喜树碱衍生物相继问世。其中，10-经基喜树碱、拓普替康、伊立替康以及9-氨基、9-硝基喜树碱、7-乙基-10-羟基喜树碱等在临床显示了广泛的抗癌活性。本文综述对喜树碱衍生物的一些最新合成进展。参考文献19篇。     

HEPT类化合物的QSAR研究

为定量结构／活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法（Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物（1－[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构／活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。     

From the Micro- to the Macro-: Managing the Conservation of the Warship,Vasa

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large-scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re-treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.     

液滴荧光传感与计算机联用技术在微量分析中的应用

通过在LS55型荧光-磷光-发光分光光度计上加装液滴产生及调节附件,采用计算机采集与分析处理数据,成功地研制了双通道液滴光化学传感装置.利用葡聚糖凝胶对复合维生素B中不同组分的选择性吸附来达到分离与同时检测的目的,并将其用于复合维生素B药片的分析,取得了满意的结果.     

Using of the Agglomeration-in-liquid for the Technology of the Fine Materials

The content of the fine and ultrafine particles in the raw material results in difficulty of the separation, the loss of the valuable components and ecological contamination. Secondary using of the fine particles is impossible without their granulation. This problem has been solved by the agglomeration-in-liquid method.An agglomeration-in-liquid method is a process to produce agglomerates in a liquid phase from solid particles suspended in the liquid. The surface of solid particles and the binding liquid must be of identical polarity, but the continuous phase must be of the opposite polarity. The water solutions of the surfactant are the binding liquids or the organic liquids.     

On the scaling of the interface energy of the liquid clusters in the disordered nanoporous medium

Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.     

Copper-containing dendromesogens: the influence of the metal on the mesomorphism

The synthesis and liquid crystalline behaviour of the first and second generations of a dendrimeric structure based on poly(propyleneimine)(DAB-dendr(NH₂)_x) are reported. 4-(4-n-Alkoxybenzoyloxy)salicylaldehydes are used as mesogenic moieties attached at the peripheral amino groups of the dendrimers giving rise to dendromesogens with four and eight mesogenic branches. From these dendromesogens, considered as organic ligands, were prepared six metal-containing dendrimers which incorporate two or four copper atoms in their structures. All the dendrimeric ligands and three of the metal-containing dendrimers exhibit liquid crystalline properties which were studied by optical microscopy, DSC, X-ray diffraction and EPR spectroscopy.     

On the quality of the hardness kernel and the Fukui function to evaluate the global hardness

An approximated hardness kernel, which includes the second derivative with respect to the density of the kinetic energy, the electron-electron coulomb repulsion, and the exchange density functionals, has been tested for the calculation of the global hardness. The results obtained for a series of 40 cations and neutral systems and 16 anions represent in most cases an improvement of the results obtained using the HOMO-LUMO gap approach and indicate the viability of this approach to evaluate global hardness. In addition, the relevance of the Fukui function approximation and the role of the three components of the hardness kernel in the evaluation of the global hardness have been analyzed.     

Influence of the Position of the Connecting Spacer of the Chromophore on the Nonlinear Optical Response

A new chromophore, C1 , based on a similar DπA‐structure as in the FTC ‐chromophore but with a hydroxyalkyl spacer perpendicular to the direction of the dipole moment was synthesized. Both chromophores and the CLD ‐chromophore were used to prepare high T_g nonlinear optical vinyl polymers. The influence of the position of the spacer on the DπA‐system on the NLO response of the resulting polymers was investigated.

     

光亮剂对银电沉积行为的影响

用电势阶跃法和旋转圆盘电极法 (RDE)以及SEM和XRD测试手段 ,初步研究了光亮剂对氰化体系中银电沉积行为的影响 .研究表明 ,光亮剂的加入并未导致银电沉积成核机理的改变 ,但显著增强了镀液的微观平整效应 ,并且所得镀层的表观光滑程度明显改善 .XRD测试亦同时表明光亮剂的加入并未改变镀层的择优取向