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Study Information
Study Attribute Value
CEBS Accession Number: 002-01146-0001-0000-5
Chemical Name: 2',3'-Didehydro-3'-deoxythymidine
CASRN: 3056-17-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 665471_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 01/30/1990    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 Negative (Not Specified) 
0         
 50 1045 313 0.300 6.26 26.0 -26.596
Dimethyl Sulfoxide 
0         
 50 1044 426 0.408 8.52 26.0 0.000
Test Chemical 2',3'-Didehydro-3'-deoxythymidine 
17         
 50 1045 426 0.408 8.52 26.0 -0.096 
50         
 50 1045 469 0.449 9.38 26.0 9.989 
167         
 50 1041 562 0.540 11.24 26.0 32.305 
500         
 0 0 0 0.000 0.00 31.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1045 605 0.579 12.10 26.0 41.883
Mitomycin-C 
 0.004     
 10 210 183 0.871 18.30 26.0 113.561
Trend: 4.727        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 04/10/1990    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 2',3'-Didehydro-3'-deoxythymidine 
0         
 50 1051 357 0.340 7.14 26.0 -2.471
Dimethyl Sulfoxide 
0         
 50 1048 365 0.348 7.30 26.0 0.000
Test Chemical 2',3'-Didehydro-3'-deoxythymidine 
63         
 50 1049 468 0.446 9.36 26.0 28.097 
125         
 50 1046 469 0.448 9.38 26.0 28.739 
250         
 50 1046 512 0.489 10.24 26.0 40.542 
500         
 0 0 0 0.000 0.00 31.0 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1050 534 0.509 10.68 26.0 46.023
Mitomycin-C 
 0.004     
 10 209 186 0.890 18.60 26.0 155.526
Trend: 4.684        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 01/30/1990    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 Negative (Not Specified) 
0         
 50 1047 447 0.427 8.94 26.0 11.990
Dimethyl Sulfoxide 
0         
 50 1044 398 0.381 7.96 26.0 0.000
Test Chemical 2',3'-Didehydro-3'-deoxythymidine 
500         
 50 1041 410 0.394 8.20 26.0 3.312 
1667         
 50 1038 443 0.427 8.86 26.0 11.950 
5000         
 50 1043 483 0.463 9.66 26.0 21.473
Positive Control Cyclophosphamide 
 0.125     
 50 1049 695 0.663 13.90 26.0 73.791
Cyclophosphamide 
 0.5       
 10 210 223 1.062 22.30 26.0 178.550
Trend: 3.114        
Probability: 0.001