Chronic infusion of tritiated thymidine into mice with tumors

Abstract

A technique for the chronic infusion of mice is presented. Infusion of tritiated thymidine for 3 to 7 days labels most, but not all, of the cells of autochthonous breast tumors. Many of the unlabeled tumor cells are probably nonproliferating, but some may represent cells with exceptionally long intermitotic times.