Synthesis of 7-(tetrahydropyran-2-yl)- and 7-(4-acetoxytetrahydropyran-2-yl)-ε-rhodomycinone and 7-(tetrahydropyran-2-yl)-ε-pyrromycinone

The ¹³C.n.m.r spectra of water-soluble and -insoluble glucans synthesized by enzymes isolated from six strains of Streptococcus mutans are interpreted. The glucans are shown to be composed primarily of α(1→3)- and α-(1→6)-linked glucosyl residues, and the relative abundance of each linkage is estimated from peak areas. Treatment of water-insoluble glucans with dextranase is found to result in water-soluble and -insoluble products, the former enriched in α-(1→6)-linkages and the latter in α-(1→3)-linkages. The structural conclusions arrived at by ¹³C-n.m.r. spectroscopy are consistent with data from methylation analysis and ¹H-n.m.r. spectroscopy.     

一个平衡易位t(2;7)家系的染色体分析

引起流产所能观察到的遗传因素,主要是染色体异常。近年来,细胞遗传学的研究发现,具有平衡易位的夫妇容易造成流产。 本文报告的就是因反复流产而前来求诊的一对夫妇,经检查,女方为t(2;7)平衡易位携带者,其家系3代中有4人均有同样的平衡易位染色体。     

Synthesis of 7-(β-D-Glucopyranosyl)-6-Thiotheophylline and 7-(α-D-Arabinopyranosyl)-6-Thiotheopwlline. Conformational Study of the Peracetyl Derivatives.

Abstract

The synthesis of two 7-glycosyl-6-thiotheophylline nucleosides where the sugar moieties are β-D-glucose (1b) and α-D-arabinose (2b) is reported. The syn-anti equilibrium of the peracetyl derivatives was studied by the line-shape and the ¹H-NMR nOe methods, and molecular mechanics analysis.     

血管紧张素-(1-7)在动脉粥样硬化中的作用

血管紧张素-(1-7)［angiotensin(1-7), Ang-(1-7) ］是肾素-血管紧张素系 统(renin-angiotensin system, RAS)的新成员之一. 与血管紧张素Ⅱ(Ang Ⅱ)比 较,Ang-(1-7)在高血压及动脉粥样硬化等疾病中发挥着心血管保护作用. 最新研究 发现,Ang-(1-7)在平滑肌细胞增殖及迁移、内皮细胞功能、脂质代谢的这些动脉粥样硬化相关病理发展过程中起着重要作用,能够抑制动脉粥样硬化斑块的形成及加强斑块的稳定性. 本文就Ang-(1-7)与动脉粥样硬化疾病相关的最新研究进展进行综述,讨论Ang-(1-7)在动脉粥样硬化中的作用机制,也为Ang-(1-7)相关的ACE2/Ang -(1-7)/Mas轴作为未来临床治疗途径提供思路.     

血管紧张素-(1-7)的舒血管效应

实验采用兔外周动脉离体标本,在预收缩血管后,用血管紧张素[angiotensin-(1-7),Ang-(1-7)]舒张血管,比较Ang-(1-7)对外周各血管床的舒张效应并分析其产生机制。结果显示：(1)Ang-(1-7)可剂量依赖性舒张血管,但舒张作用有所不同;(2)Ang-(1-7)的舒张作用在很大程度上依赖于内皮的NO系统;(3)Ang-(1-7)的舒张血管效应不通过AT1和AT2受体。上述结果提示：Ang-(1-7)可能作用于内皮上的非AT1和AT2受体,通过调节NO释放而起舒血管作用。