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Study Information
Study Attribute Value
CEBS Accession Number: 002-01694-0004-0000-6
Chemical Name: Benzidine dihydrochloride
CASRN: 531-85-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 445801_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 03/18/1987    Harvest Time: 12 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         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Benzidine dihydrochloride 
30         
 200 4 0.020 2.0 1 0.005 0.5 3 0.015 1.5 0 0.000 0.0 
50         
 200 15 0.075 5.0 11 0.055 3.5 4 0.020 2.0 0 0.000 0.0 
75         
 200 15 0.075 7.0 7 0.035 3.0 8 0.040 4.0 0 0.000 0.0 
100         
 143 19 0.133 10.5 10 0.070 6.3 9 0.063 5.6 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 38 0.190 14.0 14 0.070 6.0 24 0.120 10.0 0 0.000 0.0
Mitomycin-C 
 0.25      
 50 21 0.420 36.0 9 0.180 16.0 12 0.240 22.0 0 0.000 0.0
Trend: 4.857 3.953 3.255  
Probability: 0.000 0.000 0.001  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 03/18/1987    Harvest Time: 13 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         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Benzidine dihydrochloride 
50         
 200 16 0.080 4.5 5 0.025 2.5 11 0.055 2.5 0 0.000 0.0 
75         
 200 24 0.120 3.5 10 0.050 2.5 14 0.070 3.0 0 0.000 0.0 
100         
 200 30 0.150 6.0 17 0.085 4.0 13 0.065 4.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
2.5       
 200 34 0.170 16.0 8 0.040 4.0 26 0.130 13.0 0 0.000 0.0
Cyclophosphamide 
7.5       
 50 22 0.440 36.0 5 0.100 8.0 17 0.340 30.0 0 0.000 0.0
Trend: 2.566 2.529 2.220  
Probability: 0.005 0.006 0.013  


Trial #:2   Activation: No Activation    Date: 04/22/1987    Harvest Time: 12 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         
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0
Test Chemical: Benzidine dihydrochloride 
30         
 200 10 0.050 5.0 1 0.005 0.5 9 0.045 4.5 0 0.000 0.0 
50         
 200 14 0.070 6.5 3 0.015 1.5 11 0.055 5.0 0 0.000 0.0 
75         
 200 33 0.165 10.5 12 0.060 3.0 21 0.105 8.5 0 0.000 0.0 
100         
 105 38 0.362 23.8 14 0.133 13.3 24 0.229 18.1 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 34 0.170 13.0 11 0.055 5.0 23 0.115 9.5 0 0.000 0.0
Mitomycin-C 
 0.25      
 50 20 0.400 36.0 8 0.160 16.0 12 0.240 24.0 0 0.000 0.0
Trend: 6.659 5.577 5.587  
Probability: 0.000 0.000 0.000