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Study Information
Study Attribute Value
CEBS Accession Number: 002-02759-0002-0000-7
Chemical Name: Pyrimethamine
CASRN: 58-14-0
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 074874_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 01/26/1983    Harvest Time: 14 hour(s)   Trial Call: Negative   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 3 0.030 3.0 1 0.010 1.0 2 0.020 2.0 0 0.000 0.0
Test Chemical: Pyrimethamine 
20         
 100 5 0.050 5.0 0 0.000 0.0 5 0.050 5.0 0 0.000 0.0 
64         
 100 7 0.070 7.0 1 0.010 1.0 6 0.060 6.0 0 0.000 0.0 
200         
 100 9 0.090 9.0 2 0.020 2.0 7 0.070 7.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.15      
 50 20 0.400 26.0 7 0.140 10.0 13 0.260 18.0 0 0.000 0.0
Trend: 1.883 0.898 1.642  
Probability: 0.030 0.185 0.050  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 01/26/1982    Harvest Time: 14 hour(s)   Trial Call: Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Dimethyl Sulfoxide 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Pyrimethamine 
20         
 100 7 0.070 6.0 1 0.010 1.0 6 0.060 5.0 0 0.000 0.0 
64         
 100 9 0.090 8.0 1 0.010 1.0 8 0.080 7.0 0 0.000 0.0 
200         
 100 9 0.090 9.0 0 0.000 0.0 9 0.090 9.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
15         
 50 10 0.200 20.0 3 0.060 6.0 7 0.140 14.0 0 0.000 0.0
Trend: 2.449 0.003 2.551  
Probability: 0.007 0.499 0.005