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Study Information
Study Attribute Value
CEBS Accession Number: 002-02551-0001-0000-6
Chemical Name: N-Methylcarbamic acid, ethyl ester
CASRN: 105-40-8
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 350735
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: 1 Experiment Call: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 80 112 79 33 25
    97 89 54 19
    125r 145 75 20
    82# 99 58 24
Test Chemical N-Methylcarbamic acid, ethyl ester 
3000         
 12 6 82 222 89*
    117# 64 95 27
    98 99 52 18
  
4000         
 54 31 66 41 35
    107 53 95 30
    93 53 98 35
  
5000         
 81 50 77 32 28
    113 63 80 24
    188r 72 109 19
Positive Control Methyl Methane Sulfonate 
5         
 75 36 547 243 191*
    83 60 465 188
    89# 60 386 144

Nonactivation Trial: 2 Experiment Call: Negative and Non-Toxic
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 74 151 75 34 28
    67 79 50 25
   
    68 70 52 25
Test Chemical N-Methylcarbamic acid, ethyl ester 
500         
 86 76 58 23 33
    66 80 80 40
    54 51 57 35
  
1000         
 62 72 68 37 35
    64 22 64 34
    87 65 93 36
  
2000         
 66 71 45 23 30
    61 42 62 34
    69 64 70 34
  
3000         
 59 44 70 39 30
    87 64 55 21
    56 49 51 31
  
5000         
 61 48 63 35 34
    74 39 76 34
    57 32 58 34
Positive Control Methyl Methane Sulfonate 
5         
 43# 29 788 608 416*
    55 65 500 302
    55 28 555 337

Induced S9 Trial: 1 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 76 102 102 45 43
    76 103 93 41
    73 92 62 28
    78 103 137 59
Test Chemical N-Methylcarbamic acid, ethyl ester 
500         
 60 144 68 38 36
    66 106 72 37
    57 169 55 32
  
1000         
 72# 70 109 50 50
    81 138 104 43
    59 135 103 58
  
2000         
 61 120 140 76 64*
    79 96 175 74
    105 176 136 43
  
3000         
 52 106 102 65 60
    55 104 89 54
    73 109 130 59
  
4000         
 60 94 115 64 72*
    48 54 152 106
    64 100 85 45
  
5000         
 41 54 132 106 93*
    63 65 150 80
Positive Control 3-Methylcholanthrene 
2.5       
 61 53 638 347 310*
    64 97 463 240
    56 94 571 342

Induced S9 Trial: 2 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 100 123 72 24 30
    114 93 90 26
    100 96 128 43
    73 88 61 28
Test Chemical N-Methylcarbamic acid, ethyl ester 
500         
 75 74 145 65 55*
    88 109 122 46
    88 87 145 55
  
1000         
 101 75 181 60 50*
    88 95 117 44
    109 98 154 47
  
2000         
 90 72 147 55 71*
    72 47 209 97
    94 43 174 62
  
3000         
 60 60 161 90 79*
    79 70 180 76
    82 72 173 70
  
4000         
 84 71 180 72 82*
    84 71 200 79
    79 49 226 96
  
5000         
 72 46 164 76 74*
    115 70 208 60
    91 57 234 85
Positive Control 3-Methylcholanthrene 
2.5       
 91 65 608 223 176*
    85 69 400 156
    107 68 478 149

Induced S9 Trial: 3 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Water 
 0         
 109 110 91 28 29
    93 95 75 27
    95 89 73 26
    79 106 85 36
Test Chemical N-Methylcarbamic acid, ethyl ester 
500         
 96 84 78 27 31
    80 83 51 21
    64 68 83 44
  
1000         
 86 63 107 41 36
    92 60 107 39
    87 80 71 27
  
2000         
 84 68 126 50 59*
    67 47 121 60
    61 34 124 68
  
3000         
 72 64 143 67 56*
    91 72 148 54
    80 66 112 47
  
4000         
 103 87 132 43 50*
    88 68 143 54
    69 50 113 54
  
5000         
 93 77 146 52 52*
    84 81 116 46
    87 73 151 58
Positive Control 3-Methylcholanthrene 
2.5       
 74 36 709 321 253*
    78 65 528 227
    82 63 523 213

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