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Study Information
Study Attribute Value
CEBS Accession Number: 002-01907-0001-0000-0
Chemical Name: Coumarin
CASRN: 91-64-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 020274_SCE
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1  Weakly Positive 
No Activation  2  Positive 
Induced Rat Liver S9  1_S9  Negative 

Trial #: 1    Activation: No Activation    Date: 05/26/1982    Trial Call: Weakly Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1044 465 0.445 9.30 26.0 0.000
Test Chemical Coumarin 
50         
 50 1047 549 0.524 10.98 26.0 17.726 
160         
 50 1044 580 0.556 11.60 26.0 24.731 
500         
 50 1047 526 0.502 10.52 28.0 12.794
Positive Control Mitomycin-C 
 0.005     
 25 524 603 1.151 24.12 26.0 158.365
Trend: 2.057        
Probability: 0.020        

Trial #: 2    Activation: No Activation    Date: 12/15/1982    Trial Call: Positive   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1043 426 0.408 8.52 26.0 0.000
Test Chemical Coumarin 
100         
 50 1048 589 0.562 11.78 26.0 37.603 
200         
 50 1047 683 0.652 13.66 26.0 59.716 
300         
 50 1038 582 0.561 11.64 26.0 37.278
Positive Control Mitomycin-C 
 0.005     
 25 523 732 1.400 29.28 26.0 242.676
Trend: 5.722        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 05/26/1982    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 100 2094 1029 0.491 10.29 26.0 0.000
Test Chemical Coumarin 
160         
 50 1044 580 0.556 11.60 26.0 13.055 
500         
 50 1039 581 0.559 11.62 26.0 13.795 
1600         
 50 1043 503 0.482 10.06 26.0 -1.860
Positive Control Cyclophosphamide 
1         
 100 2094 1714 0.819 17.14 26.0 66.569
Trend: 0.424        
Probability: 0.336