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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  Weakly Positive 
No Activation  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