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Study Information
Study Attribute Value
CEBS Accession Number: 002-01389-0003-0000-6
Chemical Name: 3,3'-Dimethoxybenzidine
CASRN: 119-90-4
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 014473_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 
Induced Rat Liver S9  2_S9  Positive 

Trial #: 1    Activation: No Activation    Date: 09/09/1980    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 1048 424 0.405 8.48 26.0 0.000
Test Chemical 3,3'-Dimethoxybenzidine 
 0.005     
 50 1050 432 0.411 8.64 26.0 1.693 
 0.05      
 50 1046 394 0.377 7.88 26.0 -6.898 
 0.5       
 50 1048 415 0.396 8.30 26.0 -2.123 
5         
 50 43 474 11.023 9.48 26.0 2624.616 
50         
 50 1043 727 0.697 14.54 26.0 72.284
Positive Control Triethylenemelamine 
 0.025     
 50 1051 2429 2.311 48.58 26.0 471.242
Trend: 17.753        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 02/04/1981    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 1050 422 0.402 8.44 26.0 0.000
Test Chemical 3,3'-Dimethoxybenzidine 
 0.5       
 50 1049 425 0.405 8.50 26.0 0.807 
1.6       
 50 1049 456 0.435 9.12 26.0 8.160 
5         
 50 1049 515 0.491 10.30 26.0 22.154 
16         
 50 1048 598 0.571 11.96 26.0 41.977 
50         
 50 1047 825 0.788 16.50 26.0 96.058
Positive Control Triethylenemelamine 
 0.025     
 50 1050 2661 2.534 53.22 26.0 530.569
Trend: 13.373        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 09/09/1980    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         
 50 1052 368 0.350 7.36 26.0 0.000
Test Chemical 3,3'-Dimethoxybenzidine 
 0.005     
 50 1053 443 0.421 8.86 26.0 20.266 
 0.05      
 50 1047 406 0.388 8.12 26.0 10.853 
 0.5       
 50 1048 405 0.386 8.10 26.0 10.474 
5         
 50 1050 419 0.399 8.38 26.0 14.076 
50         
 50 1049 433 0.413 8.66 26.0 18.000
Positive Control Cyclophosphamide 
1.5       
 50 1049 1706 1.626 34.12 26.0 364.913
Trend: 1.536        
Probability: 0.062        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 02/04/1981    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 1049 450 0.429 9.00 26.0 0.000
Test Chemical 3,3'-Dimethoxybenzidine 
50         
 50 1048 418 0.399 8.36 26.0 -7.022 
160         
 50 1048 461 0.440 9.22 26.0 2.542 
500         
 50 1049 465 0.443 9.30 26.0 3.333 
1600         
 50 1048 546 0.521 10.92 26.0 21.449 
5000         
 50 1049 719 0.685 14.38 26.0 59.778
Positive Control Cyclophosphamide 
1.5       
 50 1050 1957 1.864 39.14 26.0 334.475
Trend: 9.163        
Probability: 0.000