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Study Information
Study Attribute Value
CEBS Accession Number: 002-01391-0003-0000-9
Chemical Name: 3,3'-Dimethylbenzidine dihydrochloride
CASRN: 612-82-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 979364_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: 04/09/1982    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 1033 413 0.400 8.26 26.0 0.000
Negative (Not Specified)
0         
50 1041 391 0.376 7.82 26.0 -6.054
Test Chemical 3,3'-Dimethylbenzidine dihydrochloride
 0.5       
50 1044 420 0.402 8.40 26.0 0.623
1.6       
50 1047 429 0.410 8.58 26.0 2.485
5         
50 1038 451 0.434 9.02 26.0 8.675
16         
50 1047 486 0.464 9.72 26.0 16.102
50         
50 1039 638 0.614 12.76 26.0 53.587
Positive Control Mitomycin-C
 0.005     
50 1049 1578 1.504 31.56 26.0 276.255
Trend: 7.319        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 07/10/1982    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 Negative (Not Specified)
0         
50 1044 381 0.365 7.62 26.0 -20.688
3,3'-Dimethylbenzidine dihydrochloride
0         
50 1041 479 0.460 9.58 26.0 0.000
Test Chemical 3,3'-Dimethylbenzidine dihydrochloride
5         
50 1046 465 0.445 9.30 26.0 -3.387
10         
50 1044 576 0.552 11.52 26.0 19.905
20         
50 1038 605 0.583 12.10 26.0 26.670
40         
50 1035 767 0.741 15.34 26.0 61.054
60         
50 1041 862 0.828 17.24 26.0 79.958
80         
0 0 0 0.000 0.00 26.0 N/A
Positive Control Mitomycin-C
 0.005     
50 1050 1393 1.327 27.86 26.0 188.322
Mitomycin-C
 0.01      
50 1045 2049 1.961 40.98 26.0 326.129
Trend: 13.686        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 04/09/1982    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         
50 1042 464 0.445 9.28 26.0 0.000
Negative (Not Specified)
0         
50 1039 475 0.457 9.50 26.0 2.666
Test Chemical 3,3'-Dimethylbenzidine dihydrochloride
1.6       
50 1044 417 0.399 8.34 26.0 -10.301
5         
50 1049 435 0.415 8.70 26.0 -6.876
16         
50 1039 460 0.443 9.20 26.0 -0.576
50         
50 1032 407 0.394 8.14 26.0 -11.435
160         
50 1038 439 0.423 8.78 26.0 -5.023
500         
50 1037 484 0.467 9.68 26.0 4.813
Positive Control Cyclophosphamide
2         
50 1047 3560 3.400 71.20 26.0 663.577
Trend: 0.852        
Probability: 0.197