For an EPR spectral intensity standard useful for human biophysical dosimetry, the following are the requirements: 1) A solid standard which is non-hygroscopic 2) Should have an EPR spectrum which can be measured at room temperature. 3) The spectrum should be non-overlapping with the radiation-induced signals from teeth. 4) The standard sample should be easily prepared and standardized. Several groups have tried to develop such an EPR spectral intensity standard with the above mentioned properties but did not succeed. We have developed successfully a standard which complies with the criteria described above. In brief, we grew single crystals of the diamagnetic compound, 4-hydroxy 2,2,6,6 tetramethyl piperidine by slow evaporation. During crystal growth, we doped the paramagnetic molecule, 4-hydroxy 2,2,6,6 tetramethyl piperidine-1-oxyl, which has significant structural similarity with the host molecule. We obtained crystals using several concentrations of the dopant to arrive at an EPR spectrum with intensity in the range of the radiation-induced signals in the teeth.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Investigator-Initiated Intramural Research Projects (ZIA)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
National Cancer Institute Division of Basic Sciences
Zip Code
Flores-Santana, Wilmarie; Moody, Terry; Chen, Weibin et al. (2012) Nitroxide derivatives of non-steroidal anti-inflammatory drugs exert anti-inflammatory and superoxide dismutase scavenging properties in A459 cells. Br J Pharmacol 165:1058-67
Fabre, Kristin M; Saito, Keita; DeGraff, William et al. (2011) The effects of resveratrol and selected metabolites on the radiation and antioxidant response. Cancer Biol Ther 12:915-23
Matsumoto, Ken-ichiro; Hyodo, Fuminori; Anzai, Kazunori et al. (2011) Brain redox imaging. Methods Mol Biol 711:397-419
Davis, Ryan M; Mitchell, James B; Krishna, Murali C (2011) Nitroxides as cancer imaging agents. Anticancer Agents Med Chem 11:347-58
Davis, Ryan M; Matsumoto, Shingo; Bernardo, Marcelino et al. (2011) Magnetic resonance imaging of organic contrast agents in mice: capturing the whole-body redox landscape. Free Radic Biol Med 50:459-68
Davis, Ryan M; Sowers, Anastasia L; DeGraff, William et al. (2011) A novel nitroxide is an effective brain redox imaging contrast agent and in vivo radioprotector. Free Radic Biol Med 51:780-90
Samuni, Yuval; Ishii, Hisanari; Hyodo, Fuminori et al. (2010) Reactive oxygen species mediate hepatotoxicity induced by the Hsp90 inhibitor geldanamycin and its analogs. Free Radic Biol Med 48:1559-63
Samuni, Yuval; Flores-Santana, Wilmarie; Krishna, Murali C et al. (2009) The inhibitors of histone deacetylase suberoylanilide hydroxamate and trichostatin A release nitric oxide upon oxidation. Free Radic Biol Med 47:419-23