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Study Information
Study Attribute Value
CEBS Accession Number: 002-01391-0002-0000-8
Chemical Name: 3,3'-Dimethylbenzidine
CASRN: 119-93-7
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 520009_CA
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1   
Induced Rat Liver S9  1_S9  Questionable 
No Activation  2   
Induced Rat Liver S9  2_S9  Positive 
No Activation  3  Weakly Positive 

Trial #:1   Activation: No Activation    Date: 01/20/1982    Harvest Time: 18.5 hour(s)   Trial Call:   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0
Test Chemical: 3,3'-Dimethylbenzidine 
50         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
100         
 100 42 0.420 14.0 7 0.070 6.0 3 0.030 3.0 32 0.320 5.0 
200         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C 
125         
 50 19 0.380 28.0 9 0.180 8.0 10 0.200 9.0 0 0.000 0.0
Trend: 3.128 2.487 0.453  
Probability: 0.001 0.006 0.325  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 12/22/1981    Harvest Time: 10.5 hour(s)   Trial Call: Questionable   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0 1 0.010 1.0
Test Chemical: 3,3'-Dimethylbenzidine 
225         
 100 3 0.030 3.0 1 0.010 1.0 1 0.010 1.0 1 0.010 1.0 
450         
 100 40 0.400 36.0 0 0.000 0.0 40 0.400 36.0 0 0.000 0.0 
4000         
 50 1 0.020 2.0 1 0.020 2.0 0 0.000 0.0 0 0.000 0.0 
4500         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
5000         
 50 1 0.020 2.0 0 0.000 0.0 0 0.000 0.0 1 0.020 2.0
Positive Control: Cyclophosphamide 
25         
 75 9 0.120 12.0 4 0.053 5.0 4 0.053 5.0 1 0.013 1.0
Cyclophosphamide 
50         
 100 15 0.150 12.0 9 0.090 9.0 5 0.050 3.0 1 0.010 1.0
Trend: -0.043 0.718 -0.238  
Probability: 0.517 0.237 0.594  


Trial #:2   Activation: No Activation    Date: 12/22/1981    Harvest Time: 10.5 hour(s)   Trial Call:   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 2 0.020 2.0 2 0.020 2.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: 3,3'-Dimethylbenzidine 
500         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C 
1         
 50 23 0.460 34.0 8 0.160 14.0 12 0.240 20.0 3 0.060 3.0
Trend: 0.000 0.000 0.000  
Probability: 0.000 0.000 0.000  


Trial #:2_S9   Activation: Induced Rat Liver S9    Date: 01/27/1982    Harvest Time: 19.3 hour(s)   Trial Call: Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 3 0.030 3.0 2 0.020 2.0 1 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0
Test Chemical: 3,3'-Dimethylbenzidine 
400         
 100 3 0.030 3.0 0 0.000 0.0 3 0.030 3.0 0 0.000 0.0 
460         
 100 21 0.210 13.0 9 0.090 4.0 12 0.120 11.0 0 0.000 0.0 
500         
 100 21 0.210 12.0 2 0.020 2.0 19 0.190 11.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
20         
 50 35 0.700 52.0 23 0.460 38.0 12 0.240 10.0 0 0.000 0.0
Trend: 3.527 2.012 3.216  
Probability: 0.000 0.022 0.001  


Trial #:3   Activation: No Activation    Date: 01/27/1982    Harvest Time: 19.3 hour(s)   Trial Call: Weakly Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 4 0.040 4.0 4 0.040 4.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: 3,3'-Dimethylbenzidine 
125         
 100 3 0.030 3.0 2 0.020 2.0 1 0.010 1.0 0 0.000 0.0 
150         
 100 7 0.070 6.0 5 0.050 4.0 2 0.020 2.0 0 0.000 0.0 
180         
 100 53 0.530 12.0 10 0.100 7.0 3 0.030 3.0 40 0.400 4.0
Positive Control: Mitomycin-C 
125         
 50 55 1.100 46.0 21 0.420 32.0 24 0.480 14.0 10 0.200 1.0
Trend: 2.494 1.219 1.840  
Probability: 0.006 0.111 0.033