Kuppusamy P, Chzhan M, Vij K, Shteynbuk M, Lefer D J, Giannella E, Zweier J L
EPR Laboratories, Johns Hopkins University School of Medicine, Francis Scott Key Medical Center, Baltimore, MD 21224.
Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):3388-92. doi: 10.1073/pnas.91.8.3388.
It has been hypothesized that free radical metabolism and oxygenation in living organs and tissues such as the heart may vary over the spatially defined tissue structure. In an effort to study these spatially defined differences, we have developed electron paramagnetic resonance imaging instrumentation enabling the performance of three-dimensional spectral-spatial images of free radicals infused into the heart and large vessels. Using this instrumentation, high-quality three-dimensional spectral-spatial images of isolated perfused rat hearts and rabbit aortas are obtained. In the isolated aorta, it is shown that spatially and spectrally accurate images of the vessel lumen and wall could be obtained in this living vascular tissue. In the isolated rat heart, imaging experiments were performed to determine the kinetics of radical clearance at different spatial locations within the heart during myocardial ischemia. The kinetic data show the existence of regional and transmural differences in myocardial free radical clearance. It is further demonstrated that EPR imaging can be used to noninvasively measure spatially localized oxygen concentrations in the heart. Thus, the technique of spectral-spatial EPR imaging is shown to be a powerful tool in providing spatial information regarding the free radical distribution, metabolism, and tissue oxygenation in living biological organs and tissues.
据推测，诸如心脏等活体器官和组织中的自由基代谢及氧合作用可能会随空间限定的组织结构而变化。为了研究这些空间限定的差异，我们开发了电子顺磁共振成像仪器，能够对注入心脏和大血管的自由基进行三维光谱空间成像。利用该仪器，获得了分离灌注大鼠心脏和兔主动脉的高质量三维光谱空间图像。在分离的主动脉中，结果表明在这种活体血管组织中可以获得血管腔和壁的空间及光谱精确图像。在分离的大鼠心脏中，进行了成像实验以确定心肌缺血期间心脏内不同空间位置自由基清除的动力学。动力学数据表明心肌自由基清除存在区域和透壁差异。进一步证明电子顺磁共振成像可用于无创测量心脏中空间定位的氧浓度。因此，光谱空间电子顺磁共振成像技术被证明是一种强大的工具，可提供有关活体生物器官和组织中自由基分布、代谢及组织氧合作用的空间信息。
