NITROXIDES AS POTENTIAL CONTRAST ENHANCING AGENTS FOR MRI APPLICATION - INFLUENCE OF STRUCTURE ON THE RATE OF REDUCTION BY RAT HEPATOCYTES, WHOLE LIVER HOMOGENATE, SUBCELLULAR-FRACTIONS, AND ASCORBATE
NITROXIDES AS POTENTIAL CONTRAST ENHANCING AGENTS FOR MRI APPLICATION - INFLUENCE OF STRUCTURE ON THE RATE OF REDUCTION BY RAT HEPATOCYTES, WHOLE LIVER HOMOGENATE, SUBCELLULAR-FRACTIONS, AND ASCORBATE
复制标题
DOI：
10.1002/mrm.1910050603
复制
发表时间：
1987-12-01
影响因子：
3.3
通讯作者：
ROSEN, GM
中科院分区：
文献类型：
--
作者：
KEANA, JFW;POU, S;ROSEN, GM
着眼于发展的氮氧化物作为潜在的对比增强剂的MRI应用，我们比较了大鼠全肝匀浆，肝细胞，亚细胞组分，和抗坏血酸（10当量过量）的24氮氧化物的不同结构的减少率。我们的结果表明，五元环氮氧自由基和α-羧基α-在所有体系中，芳基叔丁基氮氧自由基比六元环和杂环取代的氮氧自由基对生物还原的抵抗力显著更强。在六元环氮氧自由基的情况下，带负电荷或带正电荷的基团的存在增加了抗坏血酸还原的敏感性。羧酸基团的存在往往会增强所有氮氧自由基对肝匀浆，肝细胞和亚细胞组分的还原的抵抗力，反式氮氧自由基表现出最好的整体抵抗力对生物还原。选定的氮氧化物的T1弛豫率进行了测量，发现是相似的。
With an eye toward the development of nitroxides as potential contrast enhancing agents for MRI applications, we have compared the rates of reduction of 24 nitroxides of diverse structures by rat whole liver homogenate, hepatocytes, subcellular fractions, and ascorbate (10 eq excess). Our results indicate that five-membered ring nitroxides and .alpha.-carboxy .alpha.-aryl tert-butyl nitroxides are significantly more resistant toward bioreduction than six-membered ring and heterocyclic-substituted nitroxides in all systems. In the case of six-membered ring nitroxides the presence of either negatively charged or positively charged groups increases the susceptibility toward ascorbate reduction. The presence of carboxylate groups tends to enhance the resistance of all the nitroxides toward reduction by liver homogenate, hepatocytes, and subcellular fraction, trans-Azethoxyl nitroxides exhibited the best overall resistance toward bioreduction. The T1 relaxivities of selected nitroxides were measured and found to be similar.