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Study Information
Study Attribute Value
CEBS Accession Number: 002-01136-0001-0000-4
Chemical Name: 1-Phenyl-3-methyl-5-pyrazolone
CASRN: 89-25-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 837716_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  Negative 

Trial #: 1    Activation: No Activation    Date: 04/08/1985    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 1027 419 0.408 8.38 25.8 0.000
Test Chemical 1-Phenyl-3-methyl-5-pyrazolone 
50         
 50 1035 451 0.436 9.02 25.8 6.805 
166.7       
 50 1016 457 0.450 9.14 25.8 10.250 
500         
 50 1021 588 0.576 11.76 33.6 41.159 
1666.7       
 0 0 0 0.000 0.00 33.6 N/A
Positive Control Mitomycin-C 
 0.001     
 50 1025 542 0.529 10.84 25.8 29.608
Mitomycin-C 
 0.01      
 5 101 246 2.436 49.20 25.8 496.994
Trend: 5.373        
Probability: 0.000        

Trial #: 2    Activation: No Activation    Date: 04/17/1985    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         
 25 519 229 0.441 9.16 25.5 0.000
Test Chemical 1-Phenyl-3-methyl-5-pyrazolone 
249         
 25 517 277 0.536 11.08 33.3 21.429 
497.6       
 25 519 328 0.632 13.12 33.3 43.231 
753.8       
 25 519 448 0.863 17.92 33.3 95.633 
1000         
 0 0 0 0.000 0.00 33.3 N/A
Positive Control Mitomycin-C 
 0.001     
 25 520 286 0.550 11.44 25.5 24.651
Mitomycin-C 
 0.01      
 5 105 222 2.114 44.40 25.5 379.177
Trend: 8.664        
Probability: 0.000        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 04/09/1985    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 1035 439 0.424 8.78 25.8 0.000
Test Chemical 1-Phenyl-3-methyl-5-pyrazolone 
500         
 50 1033 412 0.399 8.24 25.8 -5.969 
1666.7       
 50 1026 402 0.392 8.04 25.8 -7.625 
5000         
 50 1038 472 0.455 9.44 25.8 7.206
Positive Control Cyclophosphamide 
 0.4       
 50 1036 734 0.708 14.68 25.8 67.037
Cyclophosphamide 
2         
 5 105 212 2.019 42.40 25.8 376.017
Trend: 0.918        
Probability: 0.179