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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  Weakly Positive 
No Activation  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