MAGNETIC RESONANCE IMAGING STUDIES OF HEAVY METAL DISTRIBUTION

在过去的十年中，磁共振成像(MRI)已经成为一种 重要的医疗诊断工具。这些图像中的对比度是 质子自旋密度在感兴趣体积中的函数，以及 这些自旋的松弛特性。改变的化学试剂 这些松弛属性可以改变观察到的对比度，因此 这些“造影剂”的分布已成为一种有用的诊断方法。 工具。有两种类型的试剂可用于此类目的：螯合剂 顺磁性离子，如何在临床上广泛应用，并稳定有机 激进分子。在过去的一年里，我们调查了以下因素 控制这些药物在大鼠大脑中的分布。特工们是 脑内引入，以评估潜在的诊断 这条管理途径的效用。结果发现，肯定的是 带电试剂包括裸露的金属离子以及一种螯合的Gd- HAM复合体与脑壁有很强的相关性 脑室。然而，尽管锰离子注入了 腹膜腔内迅速穿过血脑载体，观察到 对比并未显示与室壁有关。这 差异表明，给予IP的锰离子的行为更像 螯合离子，很可能与转铁蛋白络合。这些 最近，研究已经扩展到比较Gd-2的影响。 DTPA与几种稳定的有机自由基的反应。两个版本的比较 对比效应允许评估有机化合物的跨膜通量 激进分子。

Over the past decade, magnetic resonance imaging (MRI) has become an important medical diagnostic tools. The contrast in these images is a function of the density of proton spins in the volume of interest, and of the relaxation properties of these spins. Chemical agents which alter these relaxation properties can alter the observed contrast, and hence the distribution of these "contrast agents" has become a useful diagnostic tool. Two types of agents can be used for such purposes: chelated paramagnetic ions, how in widespread clinical use, and stable organic radicals. During the past year we have investigated the factors which govern the distribution of these agents in the rat brain. Agents were introduced intracerebrally in order to evaluate the potential diagnostic utility of this route of administration. It was found that positively charged agents including bare metal ions as well as a chelated Gadolinium- HAM complex were strongly associated with the walls of the cerebral ventricles. However, although manganese ions administered intraperitoneally rapidly crossed the blood brain carrier, the observed contrast did not indicate association with the ventricle walls. This difference indicates that manganese ions administered ip behave more like chelated ions, and are most probably complexed to transferrin. These studies have recently been extended to comparisons of the effects of Gd- DTPA with those of several stable organic radicals. Comparison of the contrast effects allow evaluation of the transmembrane flux of the organic radicals.