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Study Information
Study Attribute Value
CEBS Accession Number: 002-02445-0002-0000-9
Chemical Name: Methyl parathion
CASRN: 298-00-0
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 433667_CA
Study Result: Negative

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

Trial #:1   Activation: No Activation    Date: 01/04/1983    Harvest Time: 20.5 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: Negative (Not Specified) 
0         
 100 2 0.020 2.0 2 0.020 2.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl parathion 
25         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0 
75         
 100 16 0.160 6.0 5 0.050 4.0 1 0.010 1.0 10 0.100 1.0 
100         
 25 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
150         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.065     
 50 9 0.180 18.0 8 0.160 16.0 1 0.020 2.0 0 0.000 0.0
Trend: 1.646 1.500 0.245  
Probability: 0.050 0.067 0.403  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 01/12/1983    Harvest Time: 20.5 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: Negative (Not Specified) 
0         
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 3 0.030 3.0 2 0.020 2.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Methyl parathion 
200         
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 
250         
 100 6 0.060 6.0 3 0.030 3.0 3 0.030 3.0 0 0.000 0.0 
300         
 100 3 0.030 3.0 2 0.020 2.0 1 0.010 1.0 0 0.000 0.0 
350         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
10         
 50 10 0.200 16.0 6 0.120 10.0 4 0.080 6.0 0 0.000 0.0
Trend: 0.545 0.356 0.414  
Probability: 0.293 0.361 0.339