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Study Information
Study Attribute Value
CEBS Accession Number: 002-02900-0001-0000-4
Chemical Name: Theophylline
CASRN: 58-55-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 298713_SCE
Study Result: Positive

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

Trial #: 1    Activation: No Activation    Date: 03/26/1984    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 504 0.480 10.08 26.0 0.000
Test Chemical Theophylline 
10         
 50 1050 533 0.508 10.66 26.0 5.754 
30         
 0 0 0 0.000 0.00 26.0 N/A 
100         
 50 1049 668 0.637 13.36 26.0 32.666 
300         
 50 1033 713 0.690 14.26 34.0 43.796 
600         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.0015    
 50 1046 776 0.742 15.52 26.0 54.557
Mitomycin-C 
 0.01      
 5 105 223 2.124 44.60 26.0 342.460
Trend: 7.396        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 05/24/1984    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 1045 522 0.500 10.44 26.0 0.000
Test Chemical Theophylline 
201         
 50 1049 828 0.789 16.56 26.0 58.016 
300         
 50 1041 886 0.851 17.72 32.0 70.384 
405         
 50 1042 736 0.706 14.72 36.0 41.402 
510         
 0 0 0 0.000 0.00 36.0 N/A
Positive Control Mitomycin-C 
 0.0015    
 50 1042 712 0.683 14.24 26.0 36.791
Mitomycin-C 
 0.01      
 5 103 241 2.340 48.20 26.0 368.409
Trend: 5.878        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 03/26/1984    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 528 0.504 10.56 26.0 0.000
Test Chemical Theophylline 
100         
 50 1049 507 0.483 10.14 26.0 -4.160 
300         
 50 1047 582 0.556 11.64 26.0 10.227 
600         
 50 1048 536 0.511 10.72 26.0 1.418
Positive Control Cyclophosphamide 
 0.4       
 50 1045 756 0.723 15.12 26.0 43.456
Cyclophosphamide 
2         
 5 105 148 1.410 29.60 26.0 179.502
Trend: 1.113        
Probability: 0.133