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Comparison of binding of (/sup 3/H)misonidazole and (/sup 14/C)misonidazole in multicell spheroids

Journal Article · · Radiat. Res.; (United States)
DOI:https://doi.org/10.2307/3576506· OSTI ID:5828447

Uptake of (2-ring-/sup 14/C)misonidazole and (/sup 3/H)misonidazole with tritium in the side chain has been compared in 1-mm EMT-6/UW spheroids using liquid scintillation counting and autoradiography. The uptake of both labeled sensitizers as a function of incubation time was virtually identical. Uptake by the spheroids exceeded levels in the medium by 1 1/2 to 2 hr and was well modeled as a first-order binding process. The similar uptake of the two versions of this sensitizer labeled in different positions suggests that the metabolic actions which allow the drug to bind in hypoxic cells do not principally involve metabolites which separate the number 2 carbon of the imidazole ring from the side chain. The pattern of silver grains in autoradiographs was similar for both labeled sensitizers, with most labeled drug bound in an intermediate zone of cells between the necrotic center and the actively proliferating rim of the spheroids. The superior resolution possible with the tritiated compound showed that both nucleus and cytoplasm in viable looking cells were labeled while pycnotic cells were not labeled.

Research Organization:
Univ. of Washington, Seattle
OSTI ID:
5828447
Journal Information:
Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 101:3; ISSN RAREA
Country of Publication:
United States
Language:
English