title: A comparative evaluation of EPR and OxyLite oximetry using a random sampling of pO(2) in a murine tumor.
abstract: Methods currently available for the measurement of oxygen concentrations (oximetry) in viable tissues differ widely from each other in their methodological basis and applicability. The goal of this study was to compare two novel methods, particulate-based electron paramagnetic resonance (EPR) and OxyLite oximetry, in an experimental tumor model. EPR oximetry uses implantable paramagnetic particulates, whereas OxyLite uses fluorescent probes affixed on a fiber-optic cable. C3H mice were transplanted with radiation-induced fibrosarcoma (RIF-1) tumors in their hind limbs. Lithium phthalocyanine (LiPc) microcrystals were used as EPR probes. The pO(2) measurements were taken from random locations at a depth of approximately 3 mm within the tumor either immediately or 48 h after implantation of LiPc. Both methods revealed significant hypoxia in the tumor. However, there were striking differences between the EPR and OxyLite readings. The differences were attributed to the volume of tissue under examination and the effect of needle invasion at the site of measurement. This study recognizes the unique benefits of EPR oximetry in terms of robustness, repeatability and minimal invasiveness.
authors: Center for Biomedical EPR Spectroscopy and Imaging, Comprehensive Cancer Center, Davis Heart and Lung Research Institute, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors: Deepti S
authors: DS
authors: Vikram
authors: Anna
authors: A
authors: Bratasz
authors: Rizwan
authors: R
authors: Ahmad
authors: Periannan
authors: P
authors: Kuppusamy
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005260:Female; D005354:Fibrosarcoma / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000032:analysis*; D011897:Random Allocation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014018:Tissue Distribution
chemical_list: D010100:Oxygen
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