共查询到19条相似文献,搜索用时 125 毫秒
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生长抑素及其结构修饰的研究进展 总被引:5,自引:1,他引:5
生长抑素 (SST)是一种抑制脑垂体分泌生长激素的神经调节肽 ,SST通过其不同亚型的受体介导而发挥多种生物学作用。使用不同方法对SST进行结构修饰可获得不同的具有研究意义和治疗作用的结构修饰物。此文介绍了SST及其结构修饰的研究进展 相似文献
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雷公藤内酯醇的结构修饰研究进展 总被引:8,自引:0,他引:8
雷公藤Tripterygium wilfordii Hook.f.,俗名断肠草,系卫矛科雷公藤属木质藤本植物,生长于山地林缘阴湿处,分布于长江流域以南各地及西南地 相似文献
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目的 对香菇多糖化学结构的修饰方法及其生物活性进行系统总结。方法 通过查阅近年来中英文相关文献,对香菇多糖已经报道的化学结构修饰方法及修饰后的生物活性进行了系统分析,总结阶段性进展。结果 香菇多糖结构修饰方法有化学修饰,包括硫酸化、羧甲基化、磷酸化及与金属离子螯合法等,物理修饰和生物修饰法等。不同的修饰方法对香菇多糖的生物活性有较大的影响。结论 结构修饰及其药理活性的深入研究仍是香菇多糖一个重要的研究方向。 相似文献
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青霉烯是一类非典型β-内酰胺类抗生素,能用于治疗由多种耐药菌引起的重症感染。青霉烯主要分为硫取代、碳取代、杂环取代和β-内酰胺酶抑制剂。本文综述了近年来此类药物结构修饰和构效关系的研究进展,为进一步的新药研究提供参考。 相似文献
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多糖结构修饰研究进展 总被引:19,自引:0,他引:19
多糖结构修饰能提高或赋予多糖活性,降低某些多糖的毒副作用。本文对多糖结构修饰的方法,包括化学,生物和物理等方法进行了阐述,并指出对多糖结构修饰进行系统深入地研究将推动糖药物学和糖生物学的发展。 相似文献
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自西罗莫司作为免疫抑制剂应用于临床以来,便受到了人们的广泛关注。随着研究的深入,其生物利用度低、疏水性差以及结构不稳定等缺点的存在,使得该抗生素的临床应用受到了一定的限制,因此开发新型西罗莫司衍生物具有重要的研究和应用价值。近年人们对西罗莫司进行了大量的结构修饰研究,并从中获得了一系列有价值的衍生物。本文对西罗莫司结构修饰的最新研究进展作了一个简要的综述,并重点对几个结构修饰成功的西罗莫司衍生物作了较为详细的介绍。 相似文献
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Involvement of somatostatin receptor subtypes in membrane ion channel modification by somatostatin in pituitary somatotropes 总被引:10,自引:0,他引:10
1. Growth hormone (GH) secretion from pituitary somatotropes is mainly regulated by two hypothalamic hormones, GH-releasing hormone (GHRH) and somatotrophin releasing inhibitory factor (SRIF). 2. Somatotrophin releasing inhibitory factor inhibits GH secretion via activation of specific membrane receptors, somatostatin receptors (SSTRs) and signalling transduction systems in somatotropes. 3. Five subtypes of SSTRs, namely SSTR1, 2, 3, 4 and 5, have been identified, with the SSTR2 subtype divided into SSTR2A and SSTR2B. All SSTRs are G-protein-coupled receptors. 4. Voltage-gated Ca(2+) and K(+) channels on the somatotrope membrane play an important role in regulating GH secretion and SRIF modifies both channels to reduce intracellular free Ca(2+) concentration and GH secretion. 5. Using specific SSTR subtype-specific agonists, it has been found that reduction in Ca(2+) currents by SRIF is mediated by SSTR2 and an increase in K(+) currents is mediated by both SSTR2 and SSTR4 in rat somatotropes. 相似文献
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Octreotide had been exploited as a targeting ligand for nanoparticle tumor localization overexpressing somatostatin receptor. In addition to particle size and other physiochemical properties, ligand density had great influence on the delivery of active targeted nanoparticles. Herein, octreotide-targeted liposomal doxorubicin was constructed with different ligand density by post-inserting HSPE-PEG4000-Octreotide into pre-formed liposome. The octreotide ligand insertion was confirmed by activity detection of octreotide in HSPE-PEG4000-Octreotide with synchronous fluorescence. 1% octreotide density could achieve the best uptake efficiency on NCI-H-446 and SMMC-7721 cell lines among all liposomes. Octreotide-grafted long-circulating liposome (Oct-SSL) was prepared based on 1% octreotide density. The results showed that the insertion of PEG reduced cellular uptake and cytotoxicity. However, Oct-SSL showed a higher MRT compared with Oct-L showing the relative higher long circulating effect in pharmacokinetic study. Oct-SSL also showed tumor growth inhibition of twofold compared with other groups in Heps xenograft model mice. Oct-SSL with suitable ligand density and PEG modification exhibited significant effective tumor targeting for antitumor drug delivery. 相似文献
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近期的红霉素化学修饰研究导致了新型酮基内酯类抗生素和新的动能内酯类消化道动力药物的发现,前者具有抗大环内酯耐药菌活性,而后者放大了红霉素的消化道运动促进作用。本文针对酮基内酯和动能内酯研究的新进展做一简单综述。 相似文献
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目的生长抑素的分子量及其一级结构的测定。方法应用电喷雾质谱法(ESI-MS)测定了环肽药物生长抑素的分子量,用2-巯基乙醇将生长抑素的双硫键还原,再用源内碰撞诱导解离技术进行测定,根据其典型碎片离子确证其氨基酸序列。结果测得生长抑素准分子离子峰[M+H]+ m/z 1 637.8, [M+Na]+ m/z 1 659.5及[M+2Na-H]+ m/z 1 681.5,[M+2H]2+ m/z 819.5及[M+H+Na]2+ m/z 830.3,表明生长抑素的分子量为1 636.7,与理论值一致。将双硫键还原后,用CID技术进行测定,得到了一系列y和b系列的特征碎片离子,证实生长抑素还原产物的氨基酸序列为A-G-C-K-N-F-F-W-K-T-F-T-S-C。结论用ESI-MS法测得的生长抑素的分子量及一级结构与理论值相符。 相似文献
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Crider AM 《Mini reviews in medicinal chemistry》2002,2(5):507-517
Somatostatin (SRIF) is a cyclic peptide that occurs in two biologically active forms, SRIF-14 and SRIF-28. These peptides inhibit the secretion of many other peptides, including insulin and glucagon, function as neurotransmitters or neuromodulators, and exhibit potent antiproliferative activity. Recent research has led to the development of nonpeptide SRIF ligands with high affinity and selectivity at all SRIF receptor subtypes. Additionally, the newly discovered sst(2)and sst(3) antagonists will greatly facilitate our understanding of these receptors. These novel nonpeptide SRIF agonists and antagonists may have therapeutic potential in a variety of disease states. 相似文献
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通过查阅、整理、分析和总结相关文献资料,了解到:从3种开唇兰属植物中分离到包括金线莲苷在内的8种丁酸衍生物葡萄糖苷;金线莲苷具有降血糖、降血脂、保肝护肝和改善骨质疏松等的作用;人工合成金线莲苷方法包括化学方法,化学方法和酶促法相结合两种方法。金线莲苷药理活性确切,但其自然资源匮乏,人工合成金线莲苷得率低、条件难控制,因此,今后将围绕提高开唇兰植物中金线莲苷的提取率,明确金线莲苷体内的具体作用机制,并将其用于临床研究,明晰金线莲苷的生物合成途径展开。 相似文献