Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01015-0021-0000-2
Chemical Name:	1,1,1-Trichloroethane
CASRN:	71-55-6
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	920365
Study Result:	Equivocal

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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. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	97	100	41	14	21
			124r	133	57	15
			117#	123	87	25
			80	77	58	24
Test Chemical	1,1,1-Trichloroethane	0.05	67	65	30	15	18
			94	78	66	23
			110	110	47	14
		0.1	93#	78	42	15	13
			106	100	34	11
			91#	102	40.5	15
		0.2	114	98	51	15	14
			135r	92	73	18
			115	94	45	13
		0.4


Positive Control	Ethyl Methane Sulfonate	500	23	6	727	1054	1084*
			27#	13	718.5	887
			11	4	413	1311

Nonactivation Trial: 2 Experiment Call: Negative and Non-Toxic
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	85#	86	57	22	22
			85	102	64	25
			93	111	49	18
Test Chemical	1,1,1-Trichloroethane	0.05	79	90	63	27	24
			82	91	53	22
			81	88	60	25
		0.1	70	81	41	19	28
			69#	86	82	40
			63#	68	49.5	26
		0.2	75	86	59	26	30
			80#	71	81	34	30
		0.4	81	81	56	23	26
			84	69	75	30	26
		0.5	70#	69	51	24	26
			75	16	63	28
			81	69	75	31
			89	80	58	22
Positive Control	Ethyl Methane Sulfonate	500	11	5	393	1156	1156*
			8r	2	360	1440
			5r	1	348	2320

Nonactivation Trial: 3 Experiment Call: No Call
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	127r	124	83	22	34
			118	116	101	28
			88	92	89	34
			76	91	91	40
Test Chemical	1,1,1-Trichloroethane	0.05	60	78	37	20	22
			94	55	68	24	22
		0.1	72#	61	31	14	24
			75	60	67	30
			53	60	42	26
		0.2	122r	81	40	11	17
			83	59	55	22
			90	87	33	12
Positive Control	Ethyl Methane Sulfonate	500	4r	1	168	1600
			4r	1	134	1218
			2r	0	125	1923

Nonactivation Trial: 4 Experiment Call: Negative
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	112	110	114	34	26
			102#	87	78	26
			111	111	69	21
			95	92	63	22
Test Chemical	1,1,1-Trichloroethane	0.05	113	109	42	12	21
			117#	82	85	24
			108	99	88	27
		0.1	97	81	57	20	19
			103	95	70	23
			99	97	42	14
		0.2	109	68	87	27	24
			104	71	66	21	24
		0.4	94#	47	52.5	19	28
			94	8	82	29
			112	6	120	36
		0.5


Positive Control	Ethyl Methane Sulfonate	250	92	58	1115	404	375*
			81#	48	916.5	380
			94	51	961	341

Nonactivation Trial: 5 Experiment Call: Negative and Non-Toxic
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	67	80	113	56	54
			64	116	105	55
			64	102	106	55
			69	102	100	49
Test Chemical	1,1,1-Trichloroethane	0.05	65	105	97	50	48
			57	93	83	49
			52	101	72	46
		0.1	53	95	75	47	55
			42	75	86	69
			71#	105	105	49
		0.2	72	91	161	75	59
			68	88	93	45
			54	82	93	58
		0.3	66	75	104	52	52
			74	76	116	53
			86	92	134	52
		0.4	53	55	96	60	60
			55	16	109	66
			59#	59	93	53
Positive Control	Ethyl Methane Sulfonate	250	32	25	721	751	788*
			25	19	692	941
			33#	40	670	672

Non-Induced S9 Trial: 1 Experiment Call: Rejected
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	72	96	290	134	126
			73	88	260	118
			77	110	323	140
			80	106	273	114
Test Chemical	1,1,1-Trichloroethane	0.05	65	65	252	129	171
			34#	21	213	210
			55	32	285	173
		0.1	39	25	241	206	172
			61	34	217	118
			49	30	281	191
		0.2	57	30	322	189	189*
			68#	27	426	210
			66	35	331	166
		0.3	68	35	365	179	225*
			47	27	343	245
			60	19	450	250
		0.4					296*
			49	10	362	245
			48	15	497	346
		0.5


Positive Control	3-Methylcholanthrene	3.5	44	39	515	393	415*
			45	40	590	437
			45#	27	563	415

Induced S9 Trial: 1 Experiment Call: Positive
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	92	105	100	36	38
			82	86	106	43
			103	109	108	35
Test Chemical	1,1,1-Trichloroethane	0.0078	91	56	91	33	44
			99	107	159	54	44
		0.0156	102	111	154	50	57
			79	86	148	63	57
		0.0313	88	73	176	66	62*
			102	99	176	58	62*
		0.0625	85	84	133	52	44
			96	120	102	36	44
		0.125	106	75	133	42	49
			103	110	176	57	49
		0.25	96	69	217	75	82*
			97	58	256	88	82*
Positive Control	3-Methylcholanthrene	5					419*
			21	2	211	343
			22	2	326	494

Induced S9 Trial: 2 Experiment Call: Positive
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	93	93	167	60	49
			80	110	102	43
			95	87	134	47
			95	110	135	47
Test Chemical	1,1,1-Trichloroethane	0.025	87	75	241	92	68
			87	86	127	48
			100	96	193	65
		0.05	95	71	149	52	59
			101	92	189	62
			89	90	168	63
		0.1	118	92	224	63	69
			104	73	242	77
			98	78	196	66
		0.2	99	73	219	74	83*
			84	58	244	97
			103	68	236	77
		0.3	95	61	261	91	98*
			85	26	281	110
			84	17	232	92
		0.4	62	11	263	141	104*
			64	7	181	94
			98	41	228	78
		0.5


Positive Control	3-Methylcholanthrene	5	23	3	231	342	371*
			27	4	282	350
			28	3	358	421

Induced S9 Trial: 3 Experiment Call: Negative and Non-Toxic
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	99	107	121	41	38
			93	101	90	32
			106#	90	114	36
			90	102	111	41
Test Chemical	1,1,1-Trichloroethane	0.05	82	55	85	34	38
			66	74	83	42
			91	113	107	39
		0.1	86	66	75	29	34
			74	76	91	41
			90	83	85	32
		0.2	76	64	87	38	45
			88	82	138	52
			90	82	121	45
		0.3	76	57	77	34	35
			65	64	82	42
			78	65	70	30
		0.4	78	39	123	52	58*
			65	7	112	58
			82	60	156	63
		0.5	75	23	146	65	55
			77	27	103	45
			65	8	111	57
Positive Control	3-Methylcholanthrene	5	32	4	380	398	369*
			31	5	344	374
			35	6	349	334

Induced S9 Trial: 4 Experiment Call:
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	86	102	100	39	33
			95	107	100	35
			89	101	70	26
			102#	90	92	30
Test Chemical	1,1,1-Trichloroethane	0.05	79	55	70	30	32
			87	113	84	32
			64	75	68	36
		0.1	70	76	78	37	30
			86	83	71	28
			82	66	64	26
		0.2	86	82	114	44	42
			70	61	75	36
			85	82	119	47
		0.3	74	58	67	30	32
			64	66	70	37
			75	65	62	28
		0.4	79	60	134	56	49
			76	40	98	43
			61	6	87	48
		0.5	72	26	83	38	49*
			72	23	127	59
			62	8	92	49
Positive Control	3-Methylcholanthrene	5	28	5	269	324	318*
			31	5	269	289
			29	4	298	341

Induced S9 Trial: 5 Experiment Call: Negative and Non-Toxic
		Conc. uL/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	100	115	52	17	24
			104#	93	81	26
			98	105	69	23
			104#	86	85.5	28
Test Chemical	1,1,1-Trichloroethane	0.1	96	74	100	35	29
			95	95	64	23
			78	66	71	31
		0.2	98#	78	99	34	31
			95	82	85	30
			94	65	85	30
Positive Control	3-Methylcholanthrene	2.5	96	56	638	221	218*
			88#	56	592.5	225
			79	54	491	207

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