It has long been believed that the predominant toxic product of ionizing radiation is the hydroxyl free radical. Its short lifetime makes it extremely difficult to measure. However, the applicants have recently measured radiation induced hydroxyl radical production directly in a murine leg tumor in real time, using a new technique developed in their laboratory. The hydroxyl radical was detected at the site where it evolved with a novel very low frequency electron paramagnetic resonance (EPR) spectroscopy in combination with new, robust in vivo spin trapping techniques. This is a noninvasive technique, which does not involve injury or destruction of the animal/patient subject. These studies, although preliminary, will eventually correlate the evolution of free radicals with the biologic effect of ionizing radiation. This, for example, will allow the applicants to predict that component of radiation effect that can be modulated by scavenging hydroxyl radicals and develop strategies to optimally modulate those radiation effects. The conditions of the initial measurement, however, were extreme. The objective of this grant application is to further develop spin/trapping/low frequency EPR spectroscopy to localize radiation induced hydroxyl radical formation at clinically relevant radiation doses in vivo and in real time in intracellular, interstitial and vascular compartments. The investigators will use this technique to probe thiol protection from radiation damage to further understand basic mechanisms of the biological effect of ionizing radiation in animals.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA069538-02
Application #
2414437
Study Section
Biophysical Chemistry Study Section (BBCB)
Project Start
1996-07-01
Project End
2000-04-30
Budget Start
1997-05-01
Budget End
1998-04-30
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Chicago
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
225410919
City
Chicago
State
IL
Country
United States
Zip Code
60637
Cao, Guan-Liang; Zhang, Bin; Domachowske, Joseph B et al. (2002) Introduction of NOS II gene into primary cultures of bovine and human endothelial cells. Methods Mol Biol 196:239-45
Williams, Benjamin B; al Hallaq, Hania; Chandramouli, G V R et al. (2002) Imaging spin probe distribution in the tumor of a living mouse with 250 MHz EPR: correlation with BOLD MRI. Magn Reson Med 47:634-8
Tsai, Pei; Porasuphatana, Supatra; Halpern, Howard J et al. (2002) In vivo in situ detection of nitric oxide using low-frequency EPR spectroscopy. Methods Mol Biol 196:227-37
Stuehr, D; Pou, S; Rosen, G M (2001) Oxygen reduction by nitric-oxide synthases. J Biol Chem 276:14533-6
Rosen, G M; Tsai, P; Barth, E D et al. (2000) A one-step synthesis of 2-(2-Pyridyl)-3H-indol-3-one N-oxide: is it an efficient spin trap for hydroxyl radical? J Org Chem 65:4460-3
Zhang, B; Cao, G L; Domachowske, J et al. (2000) Stable expression of varied levels of inducible nitric oxide synthase in primary cultures of endothelial cells. Anal Biochem 286:198-205
Pou, S; Tsai, P; Porasuphatana, S et al. (1999) Spin trapping of nitric oxide by ferro-chelates: kinetic and in vivo pharmacokinetic studies. Biochim Biophys Acta 1427:216-26
Halpern, H J; Chandramouli, G V; Barth, E D et al. (1999) Diminished aqueous microviscosity of tumors in murine models measured with in vivo radiofrequency electron paramagnetic resonance. Cancer Res 59:5836-41
Pou, S; Keaton, L; Surichamorn, W et al. (1999) Mechanism of superoxide generation by neuronal nitric-oxide synthase. J Biol Chem 274:9573-80
Rosen, G M; Pou, S; Halpern, H J (1998) In vivo detection of free radicals in real time by low-frequency electron paramagnetic resonance spectroscopy. Methods Mol Biol 108:27-35

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