MAGNETIC RESONANCE IMAGING STUDIES OF HEAVY METAL DISTRIBUTION

最近，已经有可能获得空间分辨率的 生物和化学物质的核自转。磁共振 磁共振成像(MRI)正迅速发展成为临床应用的重要工具 对多种人类疾病的诊断。这样的成像研究已经 几乎完全局限于质子的检测，这提供了 生物组织中丰富的质子化分子的图像：脂肪和 水。由于像的强度依赖于质子的密度， 在给定的样本体积下，以及对核弛豫特性的影响 这些质子，就有可能研究物种的分布 这会改变这些核弛豫参数。这种依赖是 使用所谓的‘造影剂’的基础，最典型的是螯合 顺磁离子，它增强了它们进入的区域的对比度 是由于它们对松弛参数的影响而传输的。在……里面 一般情况下，此类药物的使用可能与其他 毒性。我们已经进行了几个关于分布的研究 这些化合物，包括一种相对较新的实验试剂：GdHam， 这有点不寻常，因为它带着一个净正电荷。在……里面 与以前的研究不同的是，这些药物是通过 经腹腔或静脉注射，这些药物被用来 大鼠经侧脑室注射。这条路线 给药使我们能够研究脑脊液的动力学。 这项研究的一个有趣的结果是，这些药物的分布 测试似乎依赖于带正电荷的净电荷 像GdHam这样的分子倾向于与心室表面结合。 此外，脑内注射GdHam可最大限度地减少 我们注意到与静脉注射有关的呼吸窘迫 该制剂的腹膜腔内给药。核磁共振研究使用 脑内注射氮氧化物作为造影剂也已经被 在过去的一年里进行了。

It has recently become possible to obtain spatially resolved "images" of the nuclear spins of biological and chemical materials. Magnetic resonance imaging (MRI) is rapidly evolving into an important tool for the clinical diagnosis of a wide range of human pathologies. Such imaging studies have been almost exclusively limited to the detection of protons, which provide images of the abundant protonated molecules in biological tissues: fat and water. Since image intensity is dependent on the density of protons in a given sample volume, as well as on the nuclear relaxation properties of these protons, it becomes possible to study the distribution of species which can alter these nuclear relaxation parameters. This dependence is the basis for the use of so called 'contrast agents', most typically chelated paramagnetic ions, which enhance the contrast of regions into which they are transported as a result of their effects on relaxation parameters. In general , the use of such agents may be associated with additional toxicity. We have carried out studies of the distribution of several of these compounds, including a relatively new, experimental agent: GdHam, which is somewhat unusual in that it carries a net positive charge. In contrast to previous studies in which the agents are introduced via intraperitoneal or intravenous injection, these agents were administered to rats intracerebrally via the lateral ventricle. This route of administration allowed us to study the dynamics of the cerebrospinal fluid. One interesting result of this study is that the distribution of the agents tested appears to depend on the net charge, with positively charged molecules such as GdHam tending to associate with the ventricular surfaces. In addition, intracerebral administration of GdHam minimized the respiratory distress which we have noted to be associated with intravenous intraperitoneal administration of this agent. MRI studies using intracerebrally administered nitroxides as contrast agents have also been carried out during the past year.