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Study Information
Study Attribute Value
CEBS Accession Number: 002-02150-0010-0000-1
Chemical Name: Ethyl tellurac
CASRN: 20941-65-5
NTP Study Type: Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID: 326120
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: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 141r 133 209 49 65
    104 98 181 58
    150r 114 248 55
    87 102 185 71
Test Chemical Ethyl tellurac 
1.25      
 101 94 143 47 49
    93 79 152 55
    108 94 143 44
  
2.5       
 99 90 138 47 47
    83 96 124 50
    102 101 136 44
  
5         
 115# 89 241 70 80
    101 90 269 89
    138r 123 161 39
  
10         
 100 77 163 54 66
    73 77 173 79
    93 80 181 65
  
20         
 105 44 191 61 70
    56 22 125 75
    69 21 156 76
  
30         
 73 14 238 108 134*
    65 11 262 135
    61 6 289 157
  
40         
   
   
Positive Control Ethyl Methane Sulfonate 
250         
 84# 55 1023 405 389*
    95 65 1071 377
    92 69 1063 384

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         
 91 92 158 58 62
    94 98 162 58
    89 116 188 70
    92 94 174 63
Test Chemical Ethyl tellurac 
2.5       
 90# 71 135 50 56
    75 93 150 67
    99 107 150 51
  
5         
 89 103 174 65 56
    73 103 126 58
    75 100 100 45
  
10         
 84 100 253 100 79
    89 110 159 59
    103 111 236 76
  
20         
 75 52 148 66 58
    89 64 144 54
    108 71 172 53
  
30         
 71 28 239 112 96*
    84 29 216 86
    58 27 158 91
  
40         
 62# 16 222 120 106*
    81 13 247 101
    82 14 239 98
Positive Control Ethyl Methane Sulfonate 
250         
 65 49 998 510 449*
    76 56 951 415
    75 49 949 421

Induced S9 Trial: 1 Experiment Call: Positive
  Conc.
ug/mL 		Cloning
Efficiency 		Relative Total
Growth 		Mutant Colonies Mutant Frequency Avg Mutant Frequency
Vehicle Control Dimethyl Sulfoxide 
 0         
 267r 305 180 22 71
    74# 93 197 89
    98 89 182 62
    115 118 216 63
Test Chemical Ethyl tellurac 
 0.313     
 84 77 203 80 81
    75 80 177 78
    80 105 199 83
  
 0.625     
 83 89 218 88 80
    94 86 222 78
    103 110 232 75
  
1.25      
 91# 89 192 70 89
    78# 63 227 97
    94 69 279 99
  
2.5       
 62# 41 303 164 179*
    71 28 447 210
    73 52 359 165
  
5         
 78 26 403 171 196*
    70 17 394 189
    59 14 404 228
  
10         
 63# 3 412.5 219 165*
    69 4 276 133
    63 8 274 145
Positive Control 3-Methylcholanthrene 
2.5       
 67 42 866 429 410*
    73 58 844 387
    61 61 760 413

Induced S9 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         
 99# 127 79 27 34
    86 94 84 32
    86 107 102 39
    75 72 80 36
Test Chemical Ethyl tellurac 
2.5       
 75# 54 102 45 45
    87 69 112 43
    76 63 108 47
  
5         
 106 35 173 54 57*
    72 35 156 72
    79# 50 103 43
  
7.5       
 70 28 186 88 81*
    63 27 162 86
    95 32 195 68
  
10         
 79 31 194 82 91*
    67 22 170 85
    67 21 214 107
  
15         
 82 19 244 99 111*
    81 10 266 109
    63 14 235 124
Positive Control 3-Methylcholanthrene 
2.5       
 93 54 498 179 190*
    90 72 544 203
    83 77 469 188

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