mutagenic potency at the thymidine kinase ( tk ) locus in mouse lymphoma l5178y cells ( expressed as induced trifluorothymidine ( tft ) -resistant mutants/total dose ) was assessed for 4 agents ( ethyl methanesulphonate ( ems ) , benzidine , 1,8-dinitropyrene ( 1,8-dnp ) and icrf 159 ) using short ( 3-4 h ) and long ( 21-24 h ) exposure times .
C1708726
locus
C0007634
cells