title: Liquid scintillation based quantitative measurement of dual radioisotopes (3H and 45Ca) in biological samples for bone remodeling studies.
abstract: Acute and prolonged bone complications associated with radiation and chemotherapy in cancer survivors underscore the importance of establishing a laboratory-based complementary dual-isotope tool to evaluate short- as well as long-term bone remodeling in an in vivo model. To address this need, a liquid scintillation dual-label method was investigated using different scintillation cocktails for quantitative measurement of (3)H-tetracycline ((3)H-TC) and (45)Ca as markers of bone turnover in mice. Individual samples were prepared over a wide range of known (45)Ca/(3)H activity ratios. Results showed that (45)Ca/(3)H activity ratios determined experimentally by the dual-label method were comparable to the known activity ratios (percentage difference ∼2%), but large variations were found in samples with (45)Ca/(3)H activity ratios in range of 2-10 (percentage difference ∼20-30%). Urine and fecal samples from mice administered with both (3)H-TC and (45)Ca were analyzed with the dual-label method. Positive correlations between (3)H and (45)Ca in urine (R=0.93) and feces (R=0.83) indicate that (3)H-TC and (45)Ca can be interchangeably used to monitor longitudinal in vivo skeletal remodeling.
authors: Department of Therapeutic Radiology, University of Minnesota, 420 Delaware Street SE, Mayo Mail Code 494, Minneapolis, MN 55455, USA. huixx019@umn.edu
authors: Susanta K
authors: SK
authors: Hui
authors: M
authors: M
authors: Sharma
authors: M H
authors: MH
authors: Bhattacharyya
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D001842:Bone and Bones / Q000378:metabolism; D002132:Calcium Radioisotopes / Q000493:pharmacokinetics* / Q000652:urine*; D005243:Feces / Q000737:chemistry*; D008657:Metabolic Clearance Rate; D051379:Mice; D008807:Mice, Inbred BALB C; D012588:Scintillation Counting / Q000379:methods*; D014316:Tritium / Q000493:pharmacokinetics* / Q000652:urine*
chemical_list: D002132:Calcium Radioisotopes; D014316:Tritium