Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02902-0002-0000-7
Chemical Name:	Thioacetamide
CASRN:	62-55-5
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	G54577
Study Result:	Positive

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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: Inconclusive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	68	101	64	32	47
Vehicle Control			64	99	120	63	47
Test Chemical	Thioacetamide	1311	71	89	69	32	32
			79	110	75	32	32
		1638	80	90	80	33	40
			68	85	93	46	40
		2048	74	57	130	59	57
			74	72	121	55	57
		2560	78	60	113	48	42
			71	52	76	36	42
		3200	69	33	98	47	42
			68	62	73	36	42
		4000	57	25	104	61	53
			63	36	84	44	53
Positive Control	Ethyl Methane Sulfonate	500	42	38	666	524	521*
Positive Control			42	38	653	518	521*

Nonactivation Trial: 2 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	77	99	76	33	28
Vehicle Control			75	101	50	22	28
Test Chemical	Thioacetamide	1049	93	134	58	21
			144r	195	81	19
		1311	78	86	49	21	30
			99	114	113	38	30
		1638	74	89	103	47	34
			94	136	61	22	34
		2560	81	86	146	60	47*
			92	109	95	34	47*
		3200	110	134	133	40	61*
			45	49	108	81	61*
		4000	76	98	85	37	42
			84	127	120	47	42
Positive Control	Ethyl Methane Sulfonate	500	34	25	862	841	823*
Positive Control			39	25	950	805	823*

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	112	98	117	35	44
			123r	108	149	40
			116	112	130	37
			115	90	202	59
Test Chemical	Thioacetamide	408	109	73	165	51	48
			119	90	161	45	48
		454	131r	88	186	47
			115	81	231	67
		504	94	63	148	53	56
			100	72	178	59	56
		560	124r	64	275	74
			110	59	270	82
		623	106	44	263	83	80*
			90	29	209	78	80*
		692	87	22	330	127	117*
			77	19	249	107	117*
		769	69	12	339	165	177*
			59	9	337	189	177*
		854	41	3	248	201	213*
			42	4	284	225	213*
Positive Control	Ethyl Methane Sulfonate	500	61	42	1104	603	566*
Positive Control			72	46	1143	529	566*

Non-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	114	111	122	36	42
			90	87	117	43
			122r	117	146	40
			103	102	148	48
Test Chemical	Thioacetamide	839	90	41	131	49	49
			92	85	134	48	49
		1048	86	58	159	62	70*
			94	35	218	77	70*
		1311	82	42	252	102	89*
			78	42	179	76	89*
		1638	91	76	220	80	80*
			84	56	204	81	80*
		2048	85	65	255	101	101*
			73	44	221	101	101*
		2560	90	89	225	84	85*
			80	65	207	86	85*
		3200	116	97	230	66	70*
			93	69	204	73	70*
		4000	130r	95	242	62
			107	71	225	70
		5000	79	59	248	105	96*
			76	50	200	88	96*
Positive Control	3-Methylcholanthrene	7	75	43	503	223	206*
			86	47	521	201
			100	59	581	195

Non-Induced S9 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	87	113	145	56	57
			83	96	118	47
			74	93	154	69
			80	97	137	57
Test Chemical	Thioacetamide	2560	90	99	209	78	81
			75	75	179	80
			77	70	193	84
		3200	82	83	234	95	86*
			93	102	223	80
			92	91	234	84
		4000	96#	101	168	58	76
			76	80	203	89
			93	85	224	80
		5000	90	94	198	73	85*
			77	77	204	89
			83#	91	234	94
Positive Control	3-Methylcholanthrene	7	61	39	418	228	223*
			59	51	426	242
			69#	63	408	199

Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	82	111	316	128	133
Vehicle Control			72#	89	298	137	133
Test Chemical	Thioacetamide	1966	94	77	322	114
		2458	85	68	384	150	159
			90#	68	451	168	159
		3072	76	57	343	150	162
			88	58	458	173	162
		3840	74	52	422	189	181
			87	57	449	172	181
		4800	81	58	496	205	223*
			87#	53	629	241	223*
		6000	83	55	409	164	160
			79	53	366	155	160
Positive Control	3-Methylcholanthrene	5	37	19	525	469	469*

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	114	111	196	57	60
			91	92	167	61
			133r	133	216	54
			111	97	200	60
Test Chemical	Thioacetamide	1638	108	67	292	90	88
			111	65	282	85	88
		2048	132r	85	324	82
			132r	67	312	79
		2560	115	46	314	91	100*
			104	64	342	109	100*
		3200	92	78	279	102	104*
			103	71	330	107	104*
		4000	95	67	377	132	121*
			117	64	383	109	121*
		5000	108	77	418	130	138*
			85	60	373	146	138*
Positive Control	3-Methylcholanthrene	5	86	49	698	272	271*
			68	43	586	287
			66	43	508	255

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	93	111	64	23	26
			90	107	45	17
			83	101	77	31
			70	82	67	32
Test Chemical	Thioacetamide	1310	66	68	133	67	62*
			74	70	125	56	62*
		1640	71	74	126	59	54*
			78	78	112	48	54*
		2050	73	81	113	52	68*
			64	63	161	84	68*
		2560	67	57	180	90	66*
			64	59	80	42	66*
		3200	76	70	140	62	58*
			76	68	125	55	58*
		4000	84	79	121	48	57*
			73#	69	145.5	67	57*
		5000	63	57	98	52	51*
			79	73	119	50	51*
Positive Control	3-Methylcholanthrene	5	55	39	394	241	232*
			46	33	289	210
			49	35	362	246

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