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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Correlations between in vivo tumor weight, oxygen pressure, 31P NMR spectroscopy, hypoxic microenvironment marking by beta-D-iodinated azomycin galactopyranoside (beta-D-IAZGP), and radiation sensitivity.

PURPOSE: The purpose of this study is to evaluate the amount of hypoxic fraction in a rodent tumor by means of polarographic oxygen electrode, phosphorus-31 magnetic resonance spectroscopy (31P-MRS), and a newly synthesized hypoxic marker, beta-D-iodinated azomycin galactopyranoside (beta-D-IAZGP). We also investigated the radiosensitivity for tumors of different weights. METHODS AND MATERIALS: Murine mammary carcinoma cells, FM3A, were subcutaneously implanted into the back of 5-week-old male C3H/He mice. beta-D-IAZGP radiolabeled with 123I or with 125I was injected intravenously into tumor-bearing mice, and marker distribution was measured by nuclear medicine procedures. Radiosensitivity of the tumor was measured by the in vivo/in vitro clonogenic assay. Tumor oxygenation status was also measured directly by polarographic oxygen electrodes and indirectly estimated from 31P-MR spectra. RESULTS: Higher accumulation of 123I-beta-D-IAZGP was observed in the tumors than in normal tissues at 24 h after administration. As to biodistribution of 125I-beta-D-IAZGP, the tumor/blood ratio varied widely, but correlated significantly with tumor weight. Mean oxygen pressure (pO2) values and ratios of nucleoside triphosphate beta to inorganic phosphate (beta-ATP/Pi) and of phosphocreatine to inorganic phosphate (PCr/Pi) decreased significantly with the increase in tumor volume. As tumor volume increased, the surviving fraction of cells from tumors irradiated in vivo increased significantly. CONCLUSIONS: The increase in tumor volume was significantly correlated with a reduction in mean pO2, a decrease in the ratios of beta-ATP/Pi or PCr/Pi, an increase in uptake of beta-D-IAZGP, and an increase in radioresistance. Because the uptake of beta-D-IAZGP can be measured noninvasively by nuclear medicine techniques, it could be clinically useful for monitoring hypoxia in human tumors.[1]

References

  1. Correlations between in vivo tumor weight, oxygen pressure, 31P NMR spectroscopy, hypoxic microenvironment marking by beta-D-iodinated azomycin galactopyranoside (beta-D-IAZGP), and radiation sensitivity. Saitoh, J., Sakurai, H., Suzuki, Y., Muramatsu, H., Ishikawa, H., Kitamoto, Y., Akimoto, T., Hasegawa, M., Mitsuhashi, N., Nakano, T. Int. J. Radiat. Oncol. Biol. Phys. (2002) [Pubmed]
 
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