Genetic Toxicology - Mammalian Cell Mutagenicity

Study Information
Study Attribute	Value
CEBS Accession Number:	002-01391-0013-0000-0
Chemical Name:	3,3'-Dimethylbenzidine
CASRN:	119-93-7
NTP Study Type:	Genetic Toxicology - Mammalian Cell Mutagenicity
NTP Study ID:	576643
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: No Call
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	93	104	103	37	37
			85	105	94	37
			82	112	97	39
			69	78	74	36
Test Chemical	3,3'-Dimethylbenzidine	13	63	90	113	60	47
			95	123	97	34	47
		26	77	105	113	49
		51	79	43	152	64	81*
			80	61	236	98	81*
		64	47	8	286	201
		80
		100

Positive Control	Ethyl Methane Sulfonate	500	32	23	957	992	1086*
			32	24	1088	1133
			30	25	1026	1134

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	63	104	56	29	25
			58	106	48	27
			57	94	31	18
			58	97	41	24
Test Chemical	3,3'-Dimethylbenzidine	26	53	84	81	51	44*
			58	78	63	36	44*
		33	59	95	79	44	44*
			66	102	86	43	44*
		41	36	27	107	100	75*
			39	54	58	50	75*
		51	40	17	108	91	95*
			31	18	91	99	95*
		64	18	3	60	112	94*
			27	6	61	75	94*
		80
		100

Positive Control	Ethyl Methane Sulfonate	500	45	57	915	673	687*
			40	48	772	643
			38	41	838	745

Nonactivation Trial: 3 Experiment Call: Positive
		Conc. ug/mL	Cloning Efficiency	Relative Total Growth	Mutant Colonies	Mutant Frequency	Avg Mutant Frequency
Vehicle Control	Dimethyl Sulfoxide	0	72	103	64	30	29
			75	92	80	36
			79	105	50	21
Test Chemical	3,3'-Dimethylbenzidine	26	73	94	64	29	37
			80#	104	105	44	37
		33	82	100	83	34	41
			73	100	105	48	41
		41	72	79	126	58	54*
			73	78	109	50	54*
		51	62	40	231	124	104*
			74	65	188	84	104*
		64	58	34	186	108	140*
			48	18	245	172	140*
		80	28	4	162	195	228*
			25	3	195	262	228*
		100

Positive Control	Ethyl Methane Sulfonate	500	50	44	821	544	537*
			44	48	736	564
			49	54	742	503

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	94	104	138	49	44
			82	89	140	57
			104	112	114	37
			87	95	89	34
Test Chemical	3,3'-Dimethylbenzidine	13	66	77	92	47	47
			72	90	80	37
			67	81	112	56
		26	89	84	141	53	50
			90	79	118	44
			91	96	148	54
		51	88	68	147	56	62
			106	89	237	74
			80	72	134	56
		102	88	90	93	35	49
			85	79	131	52
			81	69	145	60
		205	63	32	203	108	106*
			66	33	173	87
			66	35	240	122
		256	49	16	319	218	171*
			48	14	203	142
			45	13	206	152
		320					331*
			15	1	160	348
			15	1	143	314
		400


Positive Control	3-Methylcholanthrene	5	77	80	281	122	140*
			79	89	413	175
			81	87	297	122

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	65	127	85	44	41
			55	101	76	46
			61	72	61	34
Test Chemical	3,3'-Dimethylbenzidine	105	61	51	122	67	71*
			59	98	135	76	71*
		131	62#	47	179	97	75*
			52#	70	82	52	75*
		164	46#	38	155	112	115*
			53#	48	186	117	115*
		205	39#	28	108	92	87*
			39#	13	96	82	87*
		256	53#	30	127	80	83*
			46#	31	118	86	83*
		320
			12#	2	33	92
		400

Positive Control	3-Methylcholanthrene	5	57	85	387	226	221*
Positive Control			54	83	348	216	221*

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