The thiopurine antimetabolites 6-thioguanine and 6-mercaptopurine are important chemotherapeutic drugs in the treatment of childhood acute lymphoblastic leukaemia. Measurement of metabolites of these thiopurines is important because correlations exist between levels of these metabolites and the prognosis in childhood acute lymphoblastic leukaemia. The reversed-phase method for the determination...

-When thioguanine-resistant V79 cells are introduced into spinner flasks containing V79 multicell spheroids, the mutant cells attach to the surface of the spheroids. The composite spheroids thus formed consist of external, thioguanineresistant (TGr) and internal, thioguanine-sensitive cells. Cell sorting with a Becton Dickinson FACS II was used to determine the relative position of TGr cells an...

onists, azaserine (O-diazoacetyl-L-serine) and DON (6diazo-5-oxo-L-norleucine), in combination with either 6mercaptopurine or 6-thioguanine, synergistically inhibit the growth of a spectrum of transplanted neoplasms of rodents ; these results have been summarized in a recent review (20). In man, although the glutarnine analogs have not proved useful, the purinethiols have achieved some importan...

Cultured Chinese hamster cells were labeled with 6-3H-thymidine or 5-methyl-3H-thymidine and allowed to accumulate damage from 3H decays for various periods of time while frozen. The frequencies of cells resistant to 6-thioguanine or ouabain and the amount of DNA damage (i.e., number of single-strand breaks) were determined and compared with the mutation frequencies resulting from X and ultravi...

Cell culture studies have been performed to compare the mutagenic potential and the induction of sister chromatid exchanges for hematoporphyrin derivative photoradiation, ionizing radiation, and UV radiation. The mutation frequency in Chinese hamster ovary cells at the hypoxanthine-guanine phosphoribosyltransferase locus was measured using resistance to 6-thioguanine. Phenotypic expression time...

A selective method was devised for the isolation of "revertants" from polyoma-transformed sublines derived from BHK21/13 Syrian hamster fibroblasts. A hybrid, polyploid subline was obtained by growing together, in mixed culture in the presence of aminopterin, two variant BHK21/13 sublines lacking either inosinic acid pyrophosphorylase or thymidine kinase. Whereas these variant sublines were res...

The metabolism of 9-butyl thioguanine (9-BTG)1 was studied in normal tissues and the Ehrlich ascites tumor with and without pretreatment with azaserine. The study of the distribution and metabolism of the drug was facilitated by the synthesis of 9-butyl-6-thioguanine-8-C14. The results showed that 9-BTG was rapidly cleared from the blood, rapidly catabolized, and that the metabolites were rapid...

ase is also described. Radioactivity in plasma, brain, and muscle was determined after administration of 6-mercap topurine, 6-mercaptopurine ribonucleoside, 6-thioguanine, or 6-thioguanine ribonucleoside in mice or rats. At the times chosen for tissue sampling, there were no major differences in brain uptake between the base and ribonu cleoside pairs. Muscle radioactivity ranged from 3 to 7 tim...