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Study Information
Study Attribute Value
CEBS Accession Number: 002-01232-0001-0000-1
Chemical Name: 2,4-Toluene diisocyanate
CASRN: 584-84-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 644663_SCE
Study Result: Equivocal

Study Result: Equivocal
Activation Trial Trial Call
No Activation  1  Negative 
No Activation  2  Positive 
No Activation  3  Negative 
No Activation  4   
No Activation  5  Positive 
Induced Rat Liver S9  1_S9  Negative 
Induced Rat Liver S9  2_S9  Negative 

Trial #: 1    Activation: No Activation    Date: 04/24/1985    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 384 0.366 7.68 26.5 0.000
Test Chemical 2,4-Toluene diisocyanate 
5         
 50 1050 393 0.374 7.86 26.5 2.149 
16         
 50 1050 448 0.427 8.96 26.5 16.444 
50         
 50 1048 418 0.399 8.36 26.5 8.854 
160         
 50 1048 437 0.417 8.74 26.5 13.802 
500         
 0 0 0 0.000 0.00 26.5 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1046 582 0.556 11.64 26.5 51.852
Mitomycin-C 
 0.005     
 10 207 260 1.256 26.00 26.5 242.794
Trend: 2.048        
Probability: 0.020        

Trial #: 2    Activation: No Activation    Date: 06/04/1985    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 426 0.406 8.52 26.0 0.000
Test Chemical 2,4-Toluene diisocyanate 
200         
 50 1049 497 0.474 9.94 31.0 16.778 
300         
 50 1047 519 0.496 10.38 31.0 22.180 
400         
 50 1047 533 0.509 10.66 31.0 25.476 
500         
 50 1048 523 0.499 10.46 31.0 23.004
Positive Control Mitomycin-C 
 0.0E-4    
 50 1050 550 0.524 11.00 26.0 29.108
Mitomycin-C 
 0.005     
 10 209 242 1.158 24.20 26.0 185.397
Trend: 3.407        
Probability: 0.000        

Trial #: 3    Activation: No Activation    Date: 07/09/1985    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 458 0.437 9.16 26.0 0.000
Test Chemical 2,4-Toluene diisocyanate 
200         
 50 1048 490 0.468 9.80 31.0 6.885 
300         
 50 1050 509 0.485 10.18 31.0 10.818 
400         
 50 1048 515 0.491 10.30 31.0 12.338 
500         
 50 1050 515 0.490 10.30 31.0 12.124
Positive Control Mitomycin-C 
 0.0E-4    
 50 1047 577 0.551 11.54 26.0 25.983
Mitomycin-C 
 0.005     
 10 210 263 1.252 26.30 26.0 186.298
Trend: 1.987        
Probability: 0.023        

Trial #: 4    Activation: No Activation    Date: 08/20/1985    Trial Call:   
  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 1047 452 0.432 9.04 26.0 -11.546
Dimethyl Sulfoxide 
0         
 50 1047 511 0.488 10.22 26.0 0.000
Test Chemical 2,4-Toluene diisocyanate 
50         
 50 1051 547 0.520 10.94 26.0 6.638 
100         
 50 1046 543 0.519 10.86 26.0 6.364 
200         
 50 1049 560 0.534 11.20 31.0 9.380 
300         
 50 1049 563 0.537 11.26 31.0 9.966
Positive Control Mitomycin-C 
 0.0E-4    
 50 1051 572 0.544 11.44 26.0 11.511
Mitomycin-C 
 0.005     
 10 210 256 1.219 25.60 26.0 149.774
Trend: 1.578        
Probability: 0.057        

Trial #: 5    Activation: No Activation    Date: 10/08/1985    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 472 0.450 9.44 27.5 0.000
Test Chemical 2,4-Toluene diisocyanate 
250         
 50 1048 563 0.537 11.26 32.0 19.393 
300         
 50 1048 601 0.573 12.02 32.0 27.452 
350         
 50 1051 633 0.602 12.66 32.0 33.855 
400         
 24 503 317 0.630 13.21 32.0 40.063 
450         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.0E-4    
 50 1048 620 0.592 12.40 27.5 31.481
Mitomycin-C 
 0.005     
 10 210 260 1.238 26.00 27.5 175.161
Trend: 5.395        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 04/24/1985    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 1050 411 0.391 8.22 26.5 0.000
Test Chemical 2,4-Toluene diisocyanate 
16         
 50 1049 394 0.376 7.88 26.5 -4.045 
50         
 50 1046 386 0.369 7.72 26.5 -5.724 
160         
 50 1049 421 0.401 8.42 26.5 2.531 
500         
 0 0 0 0.000 0.00 26.5 N/A
Positive Control Cyclophosphamide 
 0.3       
 50 1051 808 0.769 16.16 26.5 96.407
Cyclophosphamide 
 0.6       
 10 210 255 1.214 25.50 26.5 210.219
Trend: 0.275        
Probability: 0.391        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 06/04/1985    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 471 0.449 9.42 26.0 0.000
Test Chemical 2,4-Toluene diisocyanate 
50         
 50 1046 445 0.425 8.90 26.0 -5.340 
100         
 50 1047 480 0.458 9.60 26.0 2.008 
250         
 50 1049 524 0.500 10.48 26.0 11.147 
500         
 50 1038 509 0.490 10.18 31.0 9.109
Positive Control Cyclophosphamide 
 0.2       
 50 1050 980 0.933 19.60 26.0 107.672
Cyclophosphamide 
 0.6       
 10 210 347 1.652 34.70 26.0 267.664
Trend: 2.374        
Probability: 0.009