1. Analysis of bromodeoxyuridine incorporation into DNA: comparison of gas chromatographic/mass spectrometric, CsCl gradient sedimentation, and specific radioactivity methods.
- Author
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Maybaum J, Kott MG, Johnson NJ, Ensminger WD, and Stetson PL
- Subjects
- Animals, Bromouracil analysis, Centrifugation, Density Gradient, Cesium, Gas Chromatography-Mass Spectrometry, Hydrolysis, Mice, Thymidine analysis, Tritium, Bromodeoxyuridine analysis, Chlorides, DNA analysis
- Abstract
A sensitive new method for the quantitation of 5-bromodeoxyuridine (BrdUrd) incorporated into DNA by GC/MS analysis of enzymatically released Thy and bromouracil (BrUra) is presented. The hydrolysis procedure was characterized and found to give uniform results when sample size was 1-10 micrograms DNA and incubation time for DNA digestion was between 40 min and 16 h. Samples of DNA containing 3H-labeled BrdUrd were analyzed in parallel by the GC/MS technique and by specific radioactivity and buoyant density measurements, in order to compare the three methods. The GC/MS procedure gave values for percentage replacement of Thy by BrUra which were higher than those obtained by specific activity and lower than those obtained by buoyant density. This GC/MS method can detect 1% replacement in a 1-microgram DNA sample, equivalent to approximately 10(5) cells or 0.1 mg tissue, and will permit sensitive and quantitative analysis of the presence of this chemotherapeutic agent/radiosensitizer in cellular DNA from biopsy samples of normal or tumor tissue.
- Published
- 1987
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