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Study Information
Study Attribute Value
CEBS Accession Number: 002-01542-0002-0000-6
Chemical Name: 5-Methoxypsoralen
CASRN: 484-20-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 197424_CA
Study Result: Positive

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

Trial #:1   Activation: No Activation    Date: 11/06/1990    Harvest Time: 12 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         
 200 2 0.010 1.0 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0
Test Chemical: 5-Methoxypsoralen 
500         
 200 35 0.175 11.5 7 0.035 3.5 28 0.140 8.5 0 0.000 0.0 
1000         
 200 47 0.235 15.5 11 0.055 4.5 35 0.175 12.5 1 0.005 1.0 
1600         
 200 77 0.385 19.5 19 0.095 8.0 58 0.290 16.5 0 0.000 0.0 
2500         
 200 53 0.265 17.5 9 0.045 4.5 42 0.210 12.5 2 0.010 2.0
Positive Control: Mitomycin-C 
 0.0625    
 200 45 0.225 18.0 17 0.085 7.0 27 0.135 11.0 1 0.005 1.0
Mitomycin-C 
 0.25      
 50 21 0.420 36.0 5 0.100 8.0 16 0.320 30.0 0 0.000 0.0
Trend: 5.582 2.891 4.914  
Probability: 0.000 0.002 0.000  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 11/06/1990    Harvest Time: 13 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         
 200 2 0.010 1.0 1 0.005 0.5 1 0.005 0.5 0 0.000 0.0
Test Chemical: 5-Methoxypsoralen 
500         
 200 14 0.070 6.0 5 0.025 2.5 9 0.045 4.5 0 0.000 0.0 
1000         
 200 21 0.105 8.5 5 0.025 2.0 15 0.075 7.0 1 0.005 1.0 
1600         
 200 10 0.050 5.0 4 0.020 2.0 6 0.030 3.0 0 0.000 0.0 
2500         
 200 17 0.085 6.5 3 0.015 1.5 14 0.070 5.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
2.5       
 200 25 0.125 10.0 4 0.020 2.0 20 0.100 9.0 1 0.005 1.0
Cyclophosphamide 
7.5       
 50 17 0.340 32.0 7 0.140 14.0 10 0.200 18.0 0 0.000 0.0
Trend: 2.102 0.555 1.836  
Probability: 0.018 0.289 0.033  


Trial #:2   Activation: No Activation    Date: 11/15/1990    Harvest Time: 12 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         
 200 2 0.010 1.0 0 0.000 0.0 2 0.010 1.0 0 0.000 0.0
Test Chemical: 5-Methoxypsoralen 
300         
 200 37 0.185 13.5 4 0.020 2.0 32 0.160 12.0 1 0.005 1.0 
500         
 200 50 0.250 15.0 11 0.055 4.5 38 0.190 13.5 1 0.005 1.0 
1000         
 200 91 0.455 26.0 24 0.120 10.0 66 0.330 22.0 1 0.005 1.0 
1600         
 200 41 0.205 13.0 12 0.060 5.5 29 0.145 11.0 0 0.000 0.0 
2500         
 200 12 0.060 5.5 3 0.015 1.5 9 0.045 4.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.0625    
 200 37 0.185 17.5 12 0.060 6.0 24 0.120 11.5 1 0.005 1.0
Mitomycin-C 
 0.25      
 50 22 0.440 32.0 11 0.220 18.0 11 0.220 22.0 0 0.000 0.0
Trend: 1.979 2.319 1.428  
Probability: 0.024 0.010 0.077