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Study Information
Study Attribute Value
CEBS Accession Number: 002-02380-0004-0000-9
Chemical Name: Malathion
CASRN: 121-75-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 973704_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: 09/21/1982    Harvest Time: 21.5 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 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Malathion 
25         
 100 3 0.030 3.0 1 0.010 1.0 1 0.010 1.0 1 0.010 1.0 
50         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0 
76         
 100 4 0.040 3.0 2 0.020 2.0 1 0.010 1.0 1 0.010 1.0 
101         
 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 
 0.062     
 50 24 0.480 34.0 15 0.300 24.0 9 0.180 18.0 0 0.000 0.0
Trend: 0.046 0.574 -0.341  
Probability: 0.482 0.283 0.633  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 09/21/1982    Harvest Time: 23.5 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: Negative (Not Specified) 
0         
 100 1 0.010 1.0 0 0.000 0.0 1 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Malathion 
303         
 100 12 0.120 10.0 7 0.070 7.0 3 0.030 3.0 2 0.020 2.0 
352         
 100 7 0.070 7.0 0 0.000 0.0 7 0.070 7.0 0 0.000 0.0 
402         
 100 86 0.860 48.0 28 0.280 23.0 58 0.580 40.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
15         
 50 14 0.280 24.0 8 0.160 16.0 6 0.120 12.0 0 0.000 0.0
Trend: 8.426 5.154 8.287  
Probability: 0.000 0.000 0.000