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Study Information
Study Attribute Value
CEBS Accession Number: 002-02439-0002-0000-2
Chemical Name: Methyl isocyanate
CASRN: 624-83-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 933693_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: 10/17/1985    Harvest Time: 20.5 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 5 0.050 4.0 1 0.010 1.0 4 0.040 3.0 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: Methyl isocyanate 
10.1       
 25 42 1.680 52.0 16 0.640 36.0 6 0.240 24.0 20 0.800 8.0 
15         
 25 60 2.400 64.0 24 0.960 44.0 16 0.640 40.0 20 0.800 8.0 
20.1       
 25 24 0.960 44.0 7 0.280 24.0 16 0.640 28.0 1 0.040 4.0 
25         
 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 
 0.04      
 100 11 0.110 10.0 5 0.050 4.0 6 0.060 6.0 0 0.000 0.0
Mitomycin-C 
 0.062     
 25 7 0.280 16.0 3 0.120 12.0 4 0.160 8.0 0 0.000 0.0
Trend: 6.600 4.811 5.192  
Probability: 0.000 0.000 0.000  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 10/17/1985    Harvest Time: 20.5 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 3 0.030 3.0 0 0.000 0.0 3 0.030 3.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 2 0.020 2.0 0 0.000 0.0 2 0.020 2.0 0 0.000 0.0
Test Chemical: Methyl isocyanate 
15         
 25 40 1.600 60.0 23 0.920 48.0 5 0.200 12.0 12 0.480 12.0 
20.1       
 25 53 2.120 52.0 17 0.680 40.0 16 0.640 32.0 20 0.800 8.0 
25         
 25 59 2.360 60.0 13 0.520 32.0 14 0.560 32.0 32 1.280 20.0 
30.5       
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Cyclophosphamide 
6.25      
 100 22 0.220 19.0 5 0.050 5.0 17 0.170 16.0 0 0.000 0.0
Cyclophosphamide 
12.5       
 25 27 1.080 56.0 14 0.560 36.0 12 0.480 28.0 1 0.040 4.0
Trend: 7.235 5.371 5.215  
Probability: 0.000 0.000 0.000  


Trial #:2   Activation: No Activation    Date: 01/30/1985    Harvest Time: 20.5 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         
 50 2 0.040 4.0 2 0.040 4.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 50 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Methyl isocyanate 
10.1       
 25 47 1.880 68.0 22 0.880 52.0 14 0.560 16.0 11 0.440 8.0 
15         
 25 40 1.600 64.0 14 0.560 40.0 15 0.600 52.0 11 0.440 8.0 
20.1       
 25 28 1.120 44.0 19 0.760 44.0 9 0.360 28.0 0 0.000 0.0 
25         
 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 
 0.05      
 50 15 0.300 20.0 9 0.180 12.0 6 0.120 12.0 0 0.000 0.0
Mitomycin-C 
 0.08      
 25 9 0.360 36.0 5 0.200 20.0 4 0.160 16.0 0 0.000 0.0
Trend: 4.629 4.243 4.441  
Probability: 0.000 0.000 0.000