Pulsed EPR imaging of nitroxides in mice

Hyodo, Fuminori ; Matsumoto, Shingo ; Devasahayam, Nallathamby ; Dharmaraj, Christopher ; Subramanian, Sankaran ; Mitchell, James B. ; Krishna, Murali C. (2009) Pulsed EPR imaging of nitroxides in mice Journal of Magnetic Resonance, 197 (2). pp. 181-185. ISSN 0022-2364

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.jmr.2008.12.018

Abstract

Nitroxides, unlike trityl radicals, have shorter T2 which until now were not detectable in vivo by a time-domain pulsed Electron Paramagnetic Resonance (EPR) spectrometer at 300 MHz since their phase memory times were shorter than the spectrometer recovery times. In the current version of the time-domain EPR spectrometer with improved spectrometer recovery times, the feasibility of detecting signals from nitroxide radicals was tested. Among the nitroxides evaluated, deuterated 15N-Tempone (15N-PDT) was found to have the longest T2. The signal intensity profile as a function of concentration of these agents was evaluated and a biphasic behavior was observed; beyond a nitroxide concentration of 1.5 mM, signal intensity was found to decrease as a result of self-broadening. Imaging experiments were carried out with 15N-PDT in solutions equilibrated with 0%, 5%, 10%, and 21% oxygen using the single point imaging (SPI) modality in EPR. The image intensity in these tubes was found to depend on the oxygen concentration which in turn influences the T2 of 15N-PDT. In vivo experiments were demonstrated with 15N-PDT in anesthetized mice where the distribution and metabolism of 15N-PDT could be monitored. This study, for the first time shows the capability to image a cell-permeable nitroxide in mice using pulsed EPR in the SPI modality.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Nitroxide; Oximetry; Pulsed EPR; Redox; Single Point Imaging
ID Code:51938
Deposited On:01 Aug 2011 07:37
Last Modified:01 Aug 2011 07:37

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