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Study Information
Study Attribute Value
CEBS Accession Number: 002-01802-0001-0000-4
Chemical Name: C.I. Pigment red 23
CASRN: 6471-49-4
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 115073_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 07/22/1986    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 401 0.382 8.02 26.0 0.000
Test Chemical C.I. Pigment red 23 
5         
 50 1049 486 0.463 9.72 26.0 21.313 
10         
 50 1049 474 0.452 9.48 26.0 18.317 
16         
 50 1046 513 0.490 10.26 26.0 28.419 
30         
 50 1047 560 0.535 11.20 26.0 40.051 
50         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 495 0.472 9.90 26.0 23.559
Mitomycin-C 
 0.005     
 10 211 299 1.417 29.90 26.0 271.051
Trend: 4.965        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 11/11/1986    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 1050 432 0.411 8.64 26.0 0.000
Test Chemical C.I. Pigment red 23 
10         
 50 1050 441 0.420 8.82 26.0 2.083 
16         
 50 1049 462 0.440 9.24 26.0 7.046 
30         
 50 1048 515 0.491 10.30 26.0 19.440 
50         
 26 546 271 0.496 10.42 31.5 20.637
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 520 0.496 10.40 26.0 20.485
Mitomycin-C 
 0.005     
 10 210 307 1.462 30.70 26.0 255.324
Trend: 3.383        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 07/22/1986    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 1048 444 0.424 8.88 26.0 0.000
Test Chemical C.I. Pigment red 23 
16         
 50 1049 445 0.424 8.90 26.0 0.130 
30         
 50 1048 500 0.477 10.00 26.0 12.613 
50         
 50 1049 487 0.464 9.74 26.0 9.580 
100         
 50 1049 506 0.482 10.12 26.0 13.855
Positive Control Cyclophosphamide 
 0.1       
 50 1049 610 0.582 12.20 26.0 37.256
Cyclophosphamide 
 0.6       
 10 210 325 1.548 32.50 26.0 265.294
Trend: 2.412        
Probability: 0.008