Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-02902-0003-0000-8
Chemical Name:	Thioacetamide
CASRN:	62-55-5
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	G77936
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: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	68	121	58	29	24
			45r	80	36	27
			58	83	29	17
			68	96	54	27
Test Chemical	Thioacetamide	156	64	96	41	21	21
			70	77	57	27
			68	70	29	14
		313	78	111	41	18	20
			71	105	56	26
			57	93	28	16
		625	58	100	60	34	29
			58	83	39	22
			60	88	55	31
		1250	54	62	47	29	23
			69	103	45	22
			63	89	34	18
		2500	47	29	72	51	47*
			52	34	73	47
			46	26	58	42
		5000	41	10	119	96	81*
			10r	1	46	153
			56	25	108	65
Positive Control	Ethyl Methane Sulfonate	500	23	17	513	760	678*
Positive Control			28	26	501	596	678*

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	67	104	50	25	23
			54	102	37	23
			70	97	48	23
			75	97	47	21
Test Chemical	Thioacetamide	156	82	116	50	20	23
			89	119	51	19
			82	95	70	28
		313	69	106	37	18	23
			67	90	51	25
			55	98	43	26
		625	82	118	59	24	26
			69	105	52	25
			85	107	70	27
		1250	73	93	78	35	34
			86	89	78	30
			62	97	69	37
		2500	96	33	238	83	71*
			69	35	146	70
			79	39	146	61
		5000	38	3	191	168	157*
			62	8	226	122
			64	5	350	182
Positive Control	Ethyl Methane Sulfonate	500	29	22	613	693	645*
			31#	30	537	577
			33	22	647	664

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	78	85	47	20	18
			79	96	35	15
			92	106	41	15
			87	112	56	21
Test Chemical	Thioacetamide	625	92	88	55	20	23
			72	84	50	23
			61	80	45	25
		1250	70	67	43	21	20
			93	79	48	17
			66	78	45	23
		1875	86	45	48	19	18
			83	30	34	14
			83	32	51	20
		2500	58	17	26	15	42*
			95	22	80	28
			22	6	54	83
		3750	82	11	75	31	26
			76	13	63	28
			64	10	40	21
		5000	70	10	58	28	40*
			72	11	91	42
			72	10	107	50
Positive Control	Ethyl Methane Sulfonate	500	44	24	894	682	575*
			49	29	748	511
			59	37	941	533

Nonactivation Trial: 4 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Water	0	103	101	89	29	31
			97	102	78	27
			96	97	108	38
Test Chemical	Thioacetamide	250	93	82	77	28	31
			83	82	83	33	31
		500	89#	81	81	30	32
			104	95	103	33
			94	98	90	32
		1000	95	27	135	48	52*
			82	29	121	49
			85	31	154	61
		2000					118*
			36	1	148	139
			55	2	159	97
		3000


Positive Control	Ethyl Methane Sulfonate	250	68#	34	1088	535	545*
			50	32	922	621
			68	39	974	477

Induced S9 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	64	81	192	99	79
			87	99	213	82
			71	111	159	75
			89	108	159	60
Test Chemical	Thioacetamide	313	60	56	143	80	75
			84	99	177	70	75
		625	86	79	177	69	63
			75	107	127	56	63
		1250	81	104	141	58	71
			58	71	146	84	71
		2500	65	62	183	93	81
			61	76	124	68	81
		5000	95	55	218	77	75
			63	50	137	73	75
Positive Control	3-Methylcholanthrene	5	37	14	536	489	488*
Positive Control			46	14	671	486	488*

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	83	95	205	82	77
			90	119	183	68
			93	89	200	72
			73	97	190	87
Test Chemical	Thioacetamide	78	97	82	224	77	89
			76	71	192	84
			82	82	259	106
		156	95	90	246	86	81
			80	103	179	74
			59	80	145	82
		313	88	113	196	74	90
			77	91	272	118
			76	47	178	78
		625	84	143	143	57	88
			75	87	223	99
			69	64	225	108
		1250	75	97	212	94	93
			74	76	202	91
			79	94	220	93
		2500	74	98	160	73	81
			81	74	194	80
			78	87	210	90
		5000	74#	78	202	91	99
			60	80	189	105
			66	78	199	101
Positive Control	3-Methylcholanthrene	5	33	7	690	708	677*
			34	6	674	667
			34	8	662	655

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