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Study Information
Study Attribute Value
CEBS Accession Number: 002-01694-0001-0000-3
Chemical Name: Benzidine
CASRN: 92-87-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 993740_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 12/09/1981    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 430 0.410 8.60 26.0 0.000
Test Chemical Benzidine 
1.6       
 50 1049 470 0.448 9.40 26.0 9.302 
5         
 50 1047 526 0.502 10.52 26.0 22.559 
16         
 37 774 526 0.680 14.22 26.0 65.788
Positive Control Mitomycin-C 
 0.005     
 25 524 669 1.277 26.76 26.0 211.460
Triethylenemelamine 
 0.015     
 25 524 820 1.565 32.80 26.0 281.759
Trend: 7.922        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 12/09/1981    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 1047 501 0.479 10.02 26.0 0.000
Test Chemical Benzidine 
50         
 50 1050 530 0.505 10.60 26.0 5.486 
160         
 50 1048 504 0.481 10.08 26.0 0.503 
500         
 50 1047 532 0.508 10.64 26.0 6.188
Positive Control Cyclophosphamide 
1         
 25 528 481 0.911 19.24 26.0 90.379
Trend: 0.666        
Probability: 0.253