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Study Information
Study Attribute Value
CEBS Accession Number: 002-03029-0002-0000-8
Chemical Name: alpha-Methylstyrene
CASRN: 98-83-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 235924_CA
Study Result: Negative

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

Trial #:1   Activation: No Activation    Date: 05/29/1986    Harvest Time: 10 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         
 200 4 0.020 2.0 2 0.010 1.0 2 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 200 6 0.030 3.0 2 0.010 1.0 4 0.020 2.0 0 0.000 0.0
Test Chemical: alpha-Methylstyrene 
100.5       
 200 1 0.005 0.5 0 0.000 0.0 1 0.005 0.5 0 0.000 0.0 
150         
 200 2 0.010 1.0 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0 
200         
 200 5 0.025 2.5 3 0.015 1.5 2 0.010 1.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.25      
 200 15 0.075 7.0 7 0.035 3.5 8 0.040 3.5 0 0.000 0.0
Mitomycin-C 
 0.75      
 25 19 0.760 56.0 6 0.240 20.0 12 0.480 40.0 1 0.040 4.0
Trend: -0.295 0.690 -0.988  
Probability: 0.616 0.245 0.838  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 05/29/1986    Harvest Time: 12 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         
 200 6 0.030 3.0 0 0.000 0.0 6 0.030 3.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 200 3 0.015 1.5 1 0.005 0.5 2 0.010 1.0 0 0.000 0.0
Test Chemical: alpha-Methylstyrene 
100.5       
 200 7 0.035 3.5 3 0.015 1.5 4 0.020 2.0 0 0.000 0.0 
150         
 200 8 0.040 4.0 5 0.025 2.5 2 0.010 1.0 1 0.005 0.5 
200         
 200 6 0.030 3.0 2 0.010 1.0 3 0.015 1.5 1 0.005 0.5
Positive Control: Cyclophosphamide 
7.5       
 200 27 0.135 12.5 8 0.040 4.0 19 0.095 8.5 0 0.000 0.0
Cyclophosphamide 
37.5       
 25 19 0.760 56.0 6 0.240 24.0 12 0.480 40.0 1 0.040 4.0
Trend: 0.970 0.765 0.101  
Probability: 0.166 0.222 0.460  


Trial #:2   Activation: No Activation    Date: 07/30/1986    Harvest Time: 10 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         
 200 4 0.020 2.0 2 0.010 1.0 2 0.010 1.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 200 2 0.010 1.0 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0
Test Chemical: alpha-Methylstyrene 
37.7       
 200 9 0.045 3.5 4 0.020 2.0 3 0.015 1.0 2 0.010 1.0 
50.3       
 200 5 0.025 2.5 2 0.010 1.0 3 0.015 1.5 0 0.000 0.0 
125.7       
 200 3 0.015 1.5 1 0.005 0.5 1 0.005 0.5 1 0.005 0.5 
251.3       
 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 
 0.25      
 200 21 0.105 9.5 6 0.030 3.0 13 0.065 6.0 2 0.010 1.0
Mitomycin-C 
 0.75      
 25 17 0.680 48.0 4 0.160 16.0 13 0.520 40.0 0 0.000 0.0
Trend: 0.050 -0.307 -0.039  
Probability: 0.480 0.621 0.516  


Trial #:2_S9   Activation: Induced Rat Liver S9    Date: 07/30/1986    Harvest Time: 12 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         
 200 6 0.030 3.0 1 0.005 0.5 4 0.020 2.0 1 0.005 0.5
Dimethyl Sulfoxide 
0         
 200 5 0.025 2.0 4 0.020 1.5 1 0.005 0.5 0 0.000 0.0
Test Chemical: alpha-Methylstyrene 
37.7       
 200 8 0.040 3.5 4 0.020 2.0 4 0.020 1.5 0 0.000 0.0 
50.3       
 200 5 0.025 2.0 2 0.010 1.0 3 0.015 1.0 0 0.000 0.0 
125.7       
 200 10 0.050 5.0 5 0.025 2.5 4 0.020 2.0 1 0.005 0.5 
251.3       
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
7.5       
 200 25 0.125 8.0 16 0.080 4.5 9 0.045 4.0 0 0.000 0.0
Cyclophosphamide 
37.5       
 25 16 0.640 56.0 9 0.360 36.0 7 0.280 24.0 0 0.000 0.0
Trend: 1.626 0.689 1.257  
Probability: 0.052 0.245 0.104