肝素新作用的研究进展

肝素（heparin）是一种结构十分复杂，承担多种独特生物功能的糖胺聚糖。其最早从动物肝脏中提取而得，当时认为硫酸类肝素是肝素中的杂质，后来发现肝素只是硫酸类肝素中高度硫酸化、结构相对规则的部分，是一类由糖醛酸和氨基己糖组成的聚阴离子糖胺聚糖类大分子。在体内，它主要由肥大细胞合成和贮藏，且与组胺一起释放。     

多组分糖胺聚糖药物舒洛地特研究进展

舒洛地特是一种经过高度纯化的多组分糖胺聚糖类生化药物,主要由快速移动肝素和硫酸皮肤素两种组分构成。此文综述了舒洛地特的化学结构和活性以及最新药理与临床应用研究进展。     

扇贝糖胺聚糖的琼脂糖凝胶电脉分析

从海湾扇贝边中提取分离出扇贝糖胺聚糖,其红外光谱与肝素类似。将扇贝糖胺聚糖制品在0.06mol/L,pH8.6巴比妥缓冲系统中进行琼脂糖凝胶电泳分析,发现其电泳图谱显示单一区带;与糖胺聚糖标准品——肝素、透明质酸和6-硫酸软骨素对照,其电泳相对迁移率与肝素量为接近。     

透明质酸与临床疾病诊断的研究进展

糖类分子以聚糖及糖蛋白等形式在细胞表面构成一层与细胞生理功能密切相关的糖衣.其中糖胺聚糖(glycominoglycan),既往又被称为粘多糖(mucopolysaccharide),是构成细胞表面糖衣的主要成分.已糖、胺和己糖醛酸或非含氮单以糖苷键相连构成双糖基本单位,而酸性糖胺聚糖即由许多重复的双糖基本单位组成.该重复双糖的基本结构是GlcUA-β1,3-GlcNAc1,4,即由葡萄糖醛酸和N-乙酸葡萄糖胺以β13键连接而成.根据这种重复双糖结合骨架结构构成的不同,可将糖胺聚糖分为4类:透明质酸,硫酸软骨素,硫酸角质素和硫酸乙酰肝素及肝素.其中,透明质酸(Hyaluronic acid,HA)由25,000个重复双糖组成,是结构最简单、分子量最小的一类糖胺聚糖,但其分子量亦达1,000万[1].     

扇贝糖胺聚糖的琼脂糖凝胶电泳分析

从海湾扇贝边中提取分离出扇贝糖胺聚糖，其红外光谱与肝素类似。将扇贝糖胺聚糖制品在０．０６ｍｏｌ／Ｌ，ｐＨ８．６巴绥缓冲系统中进行琼脂糖凝胶电泳分析，发现其电泳图谱显示单一区带。与糖胺聚糖标准品－肝素，透明质酸和６－硫酸软骨素对照，其电泳相对迁移率和肝素最为接近。     

珍珠母贝中糖胺聚糖的提取分离纯化

目的:对马氏珍珠母贝中提取、分离得到的糖胺聚糖(glycosam inog lycans,GAG)进行化学组分研究。方法:样品经还原、水解和乙酰化,采用气相色谱-质谱法定性测定。结果:测定出马氏珍珠母贝中经提取、分离得到的GAG中的3种主要成分,其骨架结构分别与(硫酸乙酰)肝素、(硫酸)软骨素和透明质酸相符。结论:马氏珍珠母贝中提取分离的糖胺聚糖中含有肝素、软骨素和透明质酸。     

低分子多糖在阿尔茨海默病防治中的研究进展

β淀粉样蛋白(Aβ)级联学说揭示了Aβ在阿尔茨海默病(AD)的发病过程中起到了关键作用。越来越多的研究发现硫酸乙酰肝素蛋白聚糖及其糖链硫酸乙酰肝素(HS)能够与Aβ相结合并促进Aβ的产生与聚积,因此硫酸乙酰肝素蛋白聚糖和HS已成为研究AD防治方法的重要靶点。此文主要介绍了近年来低分子多糖尤其是HS类似物在AD防治中的研究进展。     

硫酸寡糖的抗炎和抗过敏作用

硫酸寡糖是以糖胺聚糖为原料 ,经人工半合成方法制备的含 4～ 12个己糖醛酸和氨基己糖的硫酸化衍生物 ,平均分子量为 2 2 0 0。研究表明 ,肝素抗变态反应的作用呈分子量依赖性 ,小分子的糖胺聚糖 (平均分子量 2 4 0 0 )作用比中分子量肝素 (ＭＭＷＨ ,平均分子量6 5 0 0 )和高分子量肝素 (ＨＭＷＨ ,平均分子量 10 5 0 0 )更强 ,且此作用是由其分子中非抗凝作用部分介导的 ,活性部分存在于分子量小于 2 5 0 0的分子链中。目前国内对肝素和低分子量肝素的药理作用和临床应用研究较多 ,对硫酸寡糖的研究未见报道。本实验观察了硫酸寡糖对急性…     

细菌肝素前体(heparosan)合酶

肝素前体(heparosan)为糖胺聚糖家族一员,是某些细菌产生的荚膜多糖成分,同时也作为动物体内合成肝素、硫酸乙酰肝素的前体物,具有与肝素类似的多糖骨架。细菌heparosan合酶已引起广泛关注,因为此酶的应用可使通过化学或生物修饰生产肝素、硫酸乙酰肝素成为可能。此文对已发现的细菌heparosan合酶系统作一综述。     

HSPG和无HS-GAGs链HSPG体外抗乳腺癌的研究

目的：比较硫酸乙酰肝素蛋白聚糖（简称HSPG）和去硫酸乙酰肝素链（简称HS-GAGs链即HS链）的HSPG的体外抗人乳腺癌细胞MDA-MB-231的抗增殖和凋亡诱导作用。方法：对HSPG进行提取、纯化,硫酸乙酰肝素酶1水解HSPG的HS链;光学显微镜法观察两组分引起的细胞形态学的变化;MTT比色法检测两组分对肿瘤细胞生长曲线的影响;流式细胞术结合Annexin V-FITC及PI双染标记法观察两组分对肿瘤细胞凋亡的影响。结果：HSPG可致MDA-MB-231细胞脱落悬浮;MTT法检测结果显示HSPG对MDA-MB-231细胞增殖的抑制作用随浓度的增加而增强,而去HS链HSPG只有在高浓度时才呈现出抑制作用。HSPG能诱导MDA-MB-231的早期凋亡,而去HS链HSPG在高浓度（4 mg/mL）时对MDA-MB-231早期凋亡有诱导作用。结论：HSPG能诱导MDA-MB-231的早期凋亡和抑制细胞生长增殖。作用机制可能与HSPG的硫酸乙酰肝素链有关。     

Degraded and undegraded carrageenans and experimental gastric and duodenal ulceration

The prevention of histamine-induced gastric and duodenal ulceration in the guinea-pig has been examined using a series of undegraded and degraded carrageenans. Undegraded carrageenans were active at lower doses than degraded carrageenans. The high viscosity of the undegraded carrageenans in solution prevented their use in larger doses. Degradation of carrageenan without serious loss of sulphate, gives a product which allows the dose to be increased to an extent that its effect more than offsets the slight loss in activity caused by the degradation. No single feature of carrageenan structure can be related to anti-ulcer activity although degradation, and hence reduction of molecular size, generally reduces activity. Sulphate contents over 30% have little apparent effect on activity; κ-carrageenans were not consistently different in anti-ulcer activity from Λ-carrageenans. This contrasts with the antipeptic activity of carrageenans where κ-carrageenans are less active than their Λ-counter-parts. As with antipeptic activity, the degree of anti-ulcer activity is probably determined by a combination of structural features which includes molecular size and polyanionic properties.     

Affective and Anxiety Disorders and Alcohol and Drug Dependence:

Depression and anxiety frequently coexist in patients with substance use disorders. This clinically-oriented article examiens the relationship between these conditions and emphasizes data showing that substances of abuse can cause signs and symptoms of both depression and anxiety. These substance-related syndromes appear to have a different course and prognosis than uncomplicated, independent anxiety and major depressive disorders, and clinicians should consider the role of alcohol and other drugs in all patients presenting with these complaints. The authors will also outline an approach for diagnosing and managing patients with the combination of a substance use and depressive or anxiety disorder.     

Alcohol and Substance Use and Abuse in Women and Children

No abstract available for this article.     

Modelling and simulation of variability and uncertainty in toxicokinetics and pharmacokinetics

Two important methodological issues within the framework of the variability and uncertainty analysis of toxicokinetic and pharmacokinetic systems are discussed: (i) modelling and simulation of the existing physiologic variability in a population; and (ii) modelling and simulation of variability and uncertainty when there is insufficient or not well defined (e.g. small sample, semiquantitative, qualitative and vague) information available. Physiologically based pharmacokinetic models are especially suited for separating and characterising the physiologic variability from the overall variability and uncertainty in the system. Monte Carlo sampling should draw from multivariate distributions, which reflect all levels of existing dependencies in the intact organism. The population characteristics should be taken into account. A fuzzy simulation approach is proposed to model variability and uncertainty when there is semiquantitative, qualitative and vague information about the model parameters and their statistical distributions cannot be defined reliably.