The effects of normal metaboliteson the toxicity and antitumor activity of methotrexate against leukemia L1210 in DBA/2J mice were evaluated by a systemthat allows for long-term continuous i.v. infusion of unrestrained mice. In normal female DBA/2J mice, the infusion of methotrexatealone for 48 hr produceda 50% lethal dose of 6 mg/kg/day. Coadministrationof thymidine(5 g/kg/ day) and methotrexa...

From marker rescue, sequencing, transcript, and latency analyses of the thymidine kinase-negative herpes simplex virus mutant dlsactk and studies using the thymidine kinase inhibitor Ro 31-5140, we infer that the virus-encoded thymidine kinase is required in murine trigeminal ganglia for acute replication and lytic gene expression, for increasing the numbers of cells expressing latency-associat...

The synthesis of vaccinia virus-induced thymidine kinase is normally arrested several hours after infection. In thymidine kinase-deficient LM cells infected with IHD strain of vaccinia virus, arrest occurs whether or not viral DNA synthesis is inhibited. With virus inactivated by UV irradiation, enzyme synthesis takes place, but arrest is abolished. It is suggested that an early viral genetic f...

In an earlier study (10), it was shown that exogenous thymidine is incorporated into a precursor "pool" during the period between deoxyribonucleic acid (DNA) syntheses. The possibility was not examined, however, that the ability of cells to incorporate thymidine into the pool varied with the mitotic stage at the time of exposure. Available evidence indicates that the ability of cells to incorpo...

The purpose of this study was to determine the relationship between 2-[(11)C]thymidine positron emission tomography (PET) in vivo-derived parameters and the ex vivo Ki-67 index of proliferation in human tumors. The study comprised 17 treatment-naïve patients with advanced intra-abdominal malignancies. Tumor thymidine kinetics were measured using 2-[(11)C]thymidine PET. Tissue data were analyzed...

Isoelectric focusing was used as the final step in the isolation of thymidine phosphorylase which was found to have an isoelectric point of 4.1. Analytical acrylamide gel electrophoresis showed the purified enzyme preparation contained one major protein band which stained for thymidine phosphorylase activity and usually a minor, faster migrating band devoid of activity. Inactivation of thymidin...

background: the organochlorine ddt has estrogenic activity but the mechanism underlying the estrogenic activity of this pesticide remains unclear. in the present investigation here, we studied the transcriptional effects of a synthetic organochlorine pesticide o,p’-ddt [1.1.1.-trichloro-2-(o-chlorophenyl)-2-p-chloriphenyl ethane] and its metabolite p,p'-dde (2-2-bis(4/chlorophenyl)-1-1-dic...