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Study Information
Study Attribute Value
CEBS Accession Number: 002-02504-0009-0000-2
Chemical Name: N,N'-Diethylthiourea
CASRN: 105-55-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 142424
Study Result: Positive


Table Instructions and Notes:
Studies are indicated to be "Nontoxic" when the observed reductions in relative total growth did not indicate that the maximum tolerated dose was achieved.

Nonactivation Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 58 115 176 101 101
    61# 106 192 105
    79# 79 231 98
Test Chemical N,N'-Diethylthiourea 
600         
 84 104 205 82 84
    82 104 210 86
  
1100         
 96# 77 363 126 130
    85# 65 340.5 134
  
1600         
 68# 43 1344 657 628*
    71# 40 1276.5 599
  
2100         
 31 16 2487 2689 2408*
    42 18 2660 2128
  
2600         
 31 9 1842 2002
Positive Control Methyl Methane Sulfonate 
15         
 34# 34 262.5 259 260*
    36# 28 283.5 261

Nonactivation Trial: 3 Experiment Call:
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 71 93 70 33 40
    97 101 106 36
    85 108 96 38
    69 99 110 53
Test Chemical N,N'-Diethylthiourea 
500         
 64 95 77 40 37
    72 83 75 35
  
1000         
 76 54 105 46 46
    95 64 129 45
  
1500         
 73 15 326 148 182*
    72 15 468 216
  
2000         
 63 7 868 460 600*
    50 6 1105 739
  
2500         
   
Positive Control Methyl Methane Sulfonate 
15         
 42 37 222 177 177*
    51 32 269 176

Footnotes:
Asterisks(*) indicate significant responses.
r = rejected value due to quality control criteria
# = reduced sample size because of the loss of one culture dish due to contamination