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Electron Paramagnetic Resonance Imaging of Tumor Heterogeneity and Oxygà © nationin a Murine Model 1
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kuppusamy, Periannan Afeworki, Mobae Shankar, Ravi A. Coffin, Deborah Krishna, Murali C. Hahn, Stephen M. Mitchell, J. Brian A. Zweier, Jay L. |
| Copyright Year | 2006 |
| Abstract | Nitroxides are redox-sensitive probes, which are useful in noninvasively delineating tissue heterogeneity especially with respect to metabolic activ ity and tissue oxygénation.Recent studies have shown that nitroxides are in vitro and in vivo radioprotectors and selectively protect normal tissue compared to tumor tissue. It has been postulated that the basis for selective radioprotection of normal tissues is greater bioreduction of nitroxides in tumor tissue compared to normal tissue. The aim of the present study was to investigate the distribution and lifetime of nitroxides in tumor and normal tissues. Mice were implanted with tumor cells (RIF-1) in the thigh, and the tumor was allowed to grow to about 10-15 mm in diameter. After i.v. infusion of nitroxides, in vivo electron para magnetic resonance spectroscopy and imaging of the tumor were per formed using a specially built bridged-loop surface resonator. The pharmacokinetic and spatial distribution of the nitroxides in tumor tissue were followed and compared with those in normal tissue. Three-dimensional spatial images showed significant heterogeneity in the nitroxide distribu tion as well as reduction rates. The nitroxide reduction rates were signif icantly higher in tumors than in the normal tissue. Measurements using spin label oximetry showed a substantial difference in the level of oxygén ation between normal tissue (muscle) and tumor tissue. Average/>O2 levels in tumor tissue were found to be 3-fold lower than in a corresponding volume of normal tissue. The lower />(), levels in tumor compared to normal tissue may explain the more rapid reduction of nitroxides in these tissues. This study demonstrates that electron paramagnetic resonance imaging can perform noninvasive anatomical as well as functional imag ing and provide in vivo physiological information regarding cellular me tabolism in tumor and normal tissues. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://cancerres.aacrjournals.org/content/canres/58/7/1562.full.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
