Figure 1.
Synthetic pathway of the nucleoside tracers.
(A) 5-Iodo-2′-deoxyuridine (IUdR) is esterified on both hydroxyl groups of the deoxyribose. (B) The diesterified derivatives are trialkystannylated at position 5 of the uracil ring. (C) The tributyltannyl group is selectively exchanged by iodine-125 (radioiodination).
Figure 2.
HPLC separation on an aminopropyl-modified normal phase.
Merged HPLC chromatograms of each precursor and its corresponding iodine-125 labeled tracer (HPLC method B).
Table 1.
Susceptibility to N-glycosidic bond cleavage by thymidine phosphorylase after 0.5 and 6 h (n = 4) of incubation.
Figure 3.
Time-dependent in vitro DNA incorporation of Ac2[125I]IUdR and Piv2[125I]IUdR compared to [125I]IUdR (control).
The amount of each tracer was determined in the RNA, DNA, small molecule and protein fraction after incubation (for 0.25, 0.5, 1, 3 and 6 h) in 3 different tumor cell lines; (A) in glioma cells of the rat (CRL2397), (B) murine glioma cells (GL261) and (C) rat pheochromocytoma cells (PC12). The percentage of incubation dose was related to total protein. Values are presented as mean ± SEM (n = 3).
Table 2.
Relative radioactivity distribution of iodonucleosides 24/6 Mice (n = 6 for each tracer).
Table 3.
Uptake of iodonucleosides in tumor tissue in vivo (n = 3 for each tracer).