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Study Information
Study Attribute Value
CEBS Accession Number: 002-01390-0001-0000-6
Chemical Name: 3,3'-Dimethoxybenzidine-4,4'-diisocyanate
CASRN: 91-93-0
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 921234_SCE
Study Result: Weakly Positive

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

Trial #: 1    Activation: No Activation    Date: 08/17/1989    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 1030 495 0.481 9.90 31.0 0.000
Dimethyl Sulfoxide 
0         
 50 1024 489 0.478 9.78 26.0 -0.633
Test Chemical 3,3'-Dimethoxybenzidine-4,4'-diisocyanate 
6.7       
 50 1032 515 0.499 10.30 31.0 3.839 
20         
 50 1035 534 0.516 10.68 31.0 7.358 
67         
 50 1031 605 0.587 12.10 31.0 22.104 
200         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1045 564 0.540 11.28 26.0 12.304
Mitomycin-C 
 0.004     
 10 210 201 0.957 20.10 26.0 99.163
Trend: 3.363        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 09/12/1989    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 1036 448 0.432 8.96 26.0 -5.692
Dimethyl Sulfoxide 
0         
 50 1049 481 0.459 9.62 31.0 0.000
Test Chemical 3,3'-Dimethoxybenzidine-4,4'-diisocyanate 
13         
 50 1043 501 0.480 10.02 31.0 4.757 
25         
 50 1040 501 0.482 10.02 31.0 5.059 
50         
 50 1049 672 0.641 13.44 31.0 39.709 
100         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1051 686 0.653 13.72 26.0 42.348
Mitomycin-C 
 0.004     
 10 211 188 0.891 18.80 26.0 94.315
Trend: 5.557        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 08/17/1989    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 1047 480 0.458 9.60 26.0 0.000
Negative (Not Specified) 
0         
 50 1036 355 0.343 7.10 26.0 -25.256
Test Chemical 3,3'-Dimethoxybenzidine-4,4'-diisocyanate 
2         
 50 1041 439 0.422 8.78 26.0 -8.015 
6.7       
 50 1045 458 0.438 9.16 26.0 -4.401 
20         
 50 1038 587 0.566 11.74 26.0 23.352 
67         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Cyclophosphamide 
 0.125     
 50 1033 614 0.594 12.28 26.0 29.650
Cyclophosphamide 
 0.5       
 10 210 226 1.076 22.60 26.0 134.744
Trend: 3.475        
Probability: 0.000