Hematopoietic Effects of TCNU in Mice

Carmustine has been in clinical use since the 1960s and has proved efficacious in many treatment protocols. It has, however, been limited in its applications because of delayed hematopoietic toxicity which results in curtailment of treatment. A new derivative based on taurine, 1-(2-chloroethyl)-3-/2-(dimethylaminosulfonyl)ethyl-1-nitrosourea, has been developed and we have investigated its effects with a view to assessing the possibility of its being a causative agent for long-term marrow damage. We have found that while this new compound is less hematoxic than carmustine, it still demonstrates significant residual impairment of blood cell formation after application to mice. This impairment is noted in the CFU-S (stem cell) numbers and in the microenvironmental populations responsible for forming an ectopic site of hemopoiesis, persists for at least 180 days after the cessation of treatment, and may therefore be considered irreversible.