PURPOSE To evaluate the reproducibility of 2-[11C]thymidine positron emission tomography (PET) scanning in patients with advanced intra-abdominal malignancies. PATIENTS AND METHODS The reproducibility of 2-[11C]thymidine PET was studied by comparing interpatient and intrapatient variability (coefficient of variability, COV) of both blood and tissue data. Arterial plasma metabolite levels were...

The blastic transformation in vitro of peripheral blood lymphocytes was measured by the 72-hour uptake of tritiated thymidine ((3)H-6-thymidine) in 23 patients with mucosal ulcerative colitis, three patients with acute Crohn's colitis with rectal involvement, and seven normal subjects. The 23 patients with ulcerative colitis were subdivided into three groups, graded according to severity into s...

Previously, we demonstrated that, in some cell lines, exogenous applications of ascorbic acid (ASC) enhance the conversion frequency of white spruce (Picea glauca (Moench) Voss) somatic embryos, by stimulating mitotic activity in the apical meristems. To examine this event in more detail, we investigated the effects of ASC on de novo, salvage and degradation pathways of pyrimidine metabolism by...

We tested various thymidine analogues for induction of a senescence-like phenomenon in HeLa cells. CldU, BrdU, and IdU similarly induced the morphology of senescent cells and typical senescence markers. Thymidine analogues other than 5-halogenated forms caused only cell death. BrdU efficiently killed the cells in cooperation with irradiation with light and a brief treatment with Hoechst 33258, ...

Decarbazine induces DNA lesions in replicating DNA. We show here that deoxyribonucleosides, with the exception of thymidine, in doses of 250 microM or higher, prevent dacarbazine-induced DNA lesions. The DNA lesions that appear in the presence of thymidine can be prevented by aphidicolin, an inhibitor of DNA synthesis. Cytotoxicity analyses confirm that the combination thymidine-dacarbazine pre...

Isolated rat liver cells have been used to measure DNA repair synthesis induced by ultraviolet light and aflatoxin. Age, sex, and diet of the rats were found to influence DNA repair in rat liver cells, as measured by [3H]thymidine uptake by the cells. These effects were found to be due to variations in the thymidine pool size and should serve to indicate that high-specific-activity thymidine (i...

A single lymphocyte culture system is described which produces both reliable fragile X expression and elongated chromosomes for prometaphase analysis. This system, which is based on that described by Wheater and Roberts in 1987, involves the deoxycytidine release of a thymidine block. Eight fragile X positive subjects had an average expression level of 26%, with a range of 12% to 45%, using the...

Balanced pools of deoxyribonucleoside triphosphate precursors are required for DNA replication, and alterations of this balance are relevant to human mitochondrial diseases including mitochondrial neurogastrointestinal encephalopathy. In this disease, autosomal recessive TYMP mutations cause severe reductions of thymidine phosphorylase activity; marked elevations of the pyrimidine nucleosides t...

3-[5-{2-(2,3-Dihydroxyprop-1-yl)-o-carboran-1-yl}pentan-1-yl]thymidine (N5-2OH) is a first generation 3-carboranyl thymidine analog (3CTA) that has been intensively studied as a boron-10 ((10)B) delivery agent for neutron capture therapy (NCT). N5-2OH is an excellent substrate of thymidine kinase 1 and its favorable biodistribution profile in rodents led to successful preclinical NCT of rats be...

Thymidine depletion is toxic to virtually all actively growing cells. The fundamental mechanism responsible for thymidineless death remains unknown. One event thought to be critical in causing the toxicity of thymidine depletion is a sharp rise in the ratio of dUTP to dTTP and subsequent incorporation of dUTP into DNA. Maneuvers to alter dUTP levels appear to alter the toxicity of thymidine dep...