节杆菌9—2对皮质甾类C20-酮基的还原作用II．转化3β，17a，21-三羟基-5a-孕甾-20酮

根据多项物理性质,包括熔点、比旋值、分子旋光度、紫外光谱,红外光谱、核磁共振、质谱等的测定,确定节杆菌(Arthrobacter)9-2生物转化3β,17a,21-三羟基-5a-孕甾-3-酮(I)所生成的产物(Ⅱ)的分子结构为17a,20,21-三羟基-孕甾-1,4-二烯-3-酮,其中C20-羟基的构型是β-型。并讨论了该菌转化(I)的可能途径。     

酶稳定剂和还原剂对固定化葡萄糖氧化酶稳定性的影响

本文研究了几种酶稳定剂和还原剂对固定化葡萄糖稳定性的影响。血红蛋白能提高固定化葡萄糖氧化酶的活力,在投入酶蛋白量和血红蛋白量之比为1：10时效果最明显。此外,在底物反应液中,加入还原性物质亦能提高固定化葡萄糖氧化酶的使用稳定性,其中维生素c效果最显著。     

传入C纤维的兴奋在中电针“足三里”激活中缝大核中的作用

The purpose of the present work is to study whether the analgesia of "Zusanli" EA was mainly produced by its noxious effect. The antidromic C waves on N. peroneus communis innervating the area of "Zusanli" point were recorded. When "Zusanli" point was stimulated by trains of stimuli, the amplitude of the antidromic C wave was obviously decreased due to collision with the orthodromic stimulation. It was suggested that EA of "Zusanli" could excite some C fibers. It was observed that when the stimulation intensity reached the threshold of C fiber, the NRM neurons were obviously activated, and when it reached or exceeded the intensity for producing the maximal C wave, the NRM neurons were highly activated. Therefore, EA analgesia is probably produced mainly by its noxious stimulus component, especially carried by C fibers, via a negative feedback mechanism in modulating pain.     

锌和铜在生长抑素对链佐霉素引起的胰岛B细胞损伤的保护中的作用

我们以前的工作指出,生长抑素可以预防链佐霉素对大鼠胰岛B细胞的损伤。本工作测定给药前后大鼠血清和组织中Zn、Cu含量,以进一步观察链佐霉素破坏大鼠胰岛B细胞后生长抑素预防效应的可能机制。结果为:链佐霉素(STZ)(35mg/kg,ip)注射后24h的大鼠,血清Zn浓度下降,Cu浓度升高,Zn/Cu比值倒置;用生长抑素作预防性注射后,血清Zn浓度与正常对照水平相同,Cu浓度虽稍有升高,但Zn/Cu比值正常。保护组的血清Zn与损伤组比较,差异极为显著。两组的Zn/Cu比值同样也具有显著差异。在给药后72h,血清Zn/Cu比值在各组之间仍呈上述关系,但差异减小。在大鼠胰腺,注射链佐霉素后胰腺组织Zn浓度未见改变,但生长抑素作预防性注射可使组织锌含量增加。上述结果提示,在生长抑素对胰岛B细胞的保护机制中可能有Zn和Cu的参与。预防性注射生长抑素所引起的高Zn状态可能有利于机体细胞含Zn酶类的活性,增强已损伤细胞的修复。     

热应激时大鼠肺组织中β—肾上腺素受体的变化与膜磷...

To explore the relationship between the change of beta-adrenoceptor and the metabolism of phospholipids in lung tissue from acute heat stressed rats, the Bmax of beta-adrenoceptors, the activity of phospholipase A2 (PLA2), the content of phosphatidylcholine (PC) and phosphatidylserine (PS), and membrane fluidity in lung tissue of normal and heat stressed rats were investigated. The relevant parameter values mentioned above were 479 +/- 94 fmol/mg protein, 78.5 +/- 8.2 U, 53.5 +/- 1.7 mg/g.wet. w. and 425.1 +/- 68.1 micrograms/g.wet. w. respectively. Whereas in the heat stressed rats with rectal temperature raised to 42 degrees C for 15 min, the Bmax of beta-adrenoceptor was decreased by 43% (P less than 0.01), the activity of PLA2 increased by 83% (P less than 0.01), the contents of PC and PS decreased by 50% and 47% (P less than 0.01) respectively. A lower membrane fluidity in lung tissue for heat stressed rats was also demonstrated. The results suggest that the decreased binding sites of beta-adrenoceptor in lung tissue of rat during hyperthermia may be contributed to the activation of PLA2, which then accelerated the catabolism of phospholipids such as PC and PS in the cell plasma membrane, with a consequent alteration of membrane fluidity.     

伴刀豆蛋白A与活细胞膜作用的图像分析和多元统计

用图像分析与多元统计研究伴刀豆蛋白A(ConA)与活巨噬细胞膜受体结合时膜变形性随作用时间和ConA浓度的定量变化。结果表明膜面积增大,增大速率与ConA速度呈正相关。ConA浓度加大,膜园形系数减小,变形性增加,此等变化反应了细胞的活化。     

载脂蛋白B的分子生物学基础

载脂蛋白B(apoB)是富含甘油三酯和胆固醇的脂蛋白(CM、VLDL和LDL)特有的蛋白质成分。apoB₁₀₀是LDL受体的专一性配基,介导血中LDL-胆固醇(LDL-Ch)被外周组织细胞摄取和清除。载脂蛋白B基因遗传变异和apoB异常,血中LDL-Ch堆积,导致动脉粥样硬化发生是冠心病危险因素。     

利用~1H-NMR模拟谱研究二核苷酸A3′P(CH_3)5′A的构象性质

本文根据Altona等人的方法,在利用~1H-NMR模拟谱确定18℃、40℃、70℃三种温度下有关质子化学位移及偶合常数的基础上,分析了A3′P(CH_3)5′A的两种非对映异构体a和b的构象状态。它们与A3′P(OH)5′A相比发现:(1)在18℃时两个核糖环是S型构象占主要成分,并随温度升高S型构象成分增多;(2)磷酸骨架的扭角ε′和β′分别改变±15°及±4°;(3)在优势构象情况下,两个核糖环都部分重叠,而且A3′P(CH_3)5′A(a)的重叠程度比A3P′(CH_3)5′A(b)小;(4)腺嘌呤碱基都更倾向去堆积状态,而且随温度升高A3′P(CH_3)5′A(a)比A3′P(CH_3)5′A(b)有着更强的去堆积效应。