Tissue-specific and time-dependent clonal expansion of ENU-induced mutant cells in gpt delta mice.

DNA mutations play a crucial role in the origins of cancer, and the clonal expansion of mutant cells is one of the fundamental steps in multistage carcinogenesis. In this study, we correlated tumor incidence in B6C3F1 mice during the period after exposure to N-ethyl-N-nitrosourea (ENU) with the persistence of ENU-induced mutant clones in transgenic gpt delta B6C3F1 mice. The induced gpt mutations afforded no selective advantage in the mouse cells and could be distinguished by a mutational spectrum that is characteristic of ENU treatment.

Contrast-enhanced sonography of pancreatic ductal carcinoma using agent detection imaging.

Purpose: The aim of this study was to evaluate the enhancement behavior of pancreatic ductal carcinoma by contrast-enhanced sonography with agent detection imaging (ADI), and to clarify the origin of microbubble signals by comparisons with histological findings of resected specimens.

Methods: The subjects were 21 patients with resectable pancreatic carcinoma. The final histological diagnosis was tubular adenocarcinoma in 20 cases, and anaplastic carcinoma in one case.

[Significance of tissue thymidine phosphorylase and dihydropyrimidine dehydrogenase activities in ovarian cancer].

Thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) are important enzymes in the pyrimidine salvage pathway. In the meantime, TP and DPD are a converting enzyme of 5'-DFUR to 5-FU and the major catabolic enzyme of 5-FU, respectively. Because little is known about their protein expressions in ovarian cancers, we investigated TP and DPD protein expressions quantitatively in 24 ovarian cancers and their normal counterparts by ELISA.