TABLE E4. 



INDUCTION OF CHROMOSOMAL ABERRATIONS IN CHINESE HAMSTER OVARY CELLS 



BY NITROFURANTOIN (a) 



Trial 1 



Trial 2 



-S9(b) 



0.01 



0.00 



0.02 

 0.03 

 0,05 



1.0 

 0.0 



2.0 

 3.0 

 5.0 



Summary: Weakly positive 



(a) Study performed at Litton Bionetics, Inc, Abs = aberrations. Harvest time--20.0 hours. A detailed presentation of the tech- 

 nique for detecting chromosomal aberrations is presented by Galloway et al. ( 1985). Briefly, Chinese hamster ovary cells were 

 incubated with study compound or solvent (dimethyl sulfoxide) as indicated in (bl or (c). Cells were arrested in first metaphase 

 by addition of colcemid and harvested by mitotic shake-off, fixed, and stained in 6% Giemsa. 



(b) In the absence of S9, Chinese hamster ovary cells were incubated with study compound or solvent (dimethyl sulfoxide! for 8- 

 10 hours at 37° C. Cells were then washed, and fresh medium containing colcemid was added for an additional 2-3 hours fol- 

 lowed by harvest. 



(c) In the presence of S9, cells were incubated with study compound or solvent (dimethyl sulfoxide) for 2 hours at 37°C. Cells 

 were then washed, medium was added, and incubation was continued for 8- 10 hours. Colcemid was added for the last 2-3 hours 

 of incubation before harvest. S9 was from the liver of Aroclor 1254- induced male Sprague Daw ley rats. 



Nitrofurantoin, NTP TR 341 



198 



