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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards, well documented and acceptable for assessment (restriction: only three tester strains were used)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1977
Report Date:
1978

Materials and methods

Principles of method if other than guideline:
According to: Ames BN, McCann J, Yamasaki E (1975): Methods for detecting carcinogens and mutagens with the Salmonella/ mammalian-microsome mutagenicity test, Mutat Res 31: 47-364, with minor modifications
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: Toluidinbase/ 3,3´-Dimethyl-4,4´-diaminodiphenylmethane
- Physical state: solid, crystalline
- Analytical purity: 99%

Method

Species / strainopen allclose all
Species / strain:
other: Salmonella typhimurium TA 98, TA 100, TA 1537
Metabolic activation:
with and without
Metabolic activation system:
Liver S-9 mix from male rats treated with Aroclor 1254
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with
Metabolic activation system:
Liver S-9 mix from male rats treated with Aroclor 1254, phenobarbital or b-naphthaflavone
Test concentrations with justification for top dose:
3.15 - 3000 µg/plate
Vehicle:
DMSO
Controls
Solvent controls:
yes
Positive controls:
yes
Positive control substance:
other: see details on test system
Details on test system and conditions:
Standard platetest: The test compound dissolved in DMSO, bacterial suspension and top agar were mixed in the absence and presence of Aroclor 1254, phenobarbital or ß-naphthoflavone induced male rat liver S9-mix and poured into a minimal agar containing petri dish. After incubation for 2-3 days in the dark, his+ revertants were counted.
Test concentration without metabolic activation: 0, 31.5, 100, 315, 1000, 3000 µg/plate
Test concentration with metabolic activation: 0, 3.15, 10, 31.5, 100, 315, 1000, 3000 µg/plate
Every single experiment contained positive controls for checking the activity of the metabolizing system and the mutability of the bacteria as well as negative controls.

Positive controls:
Without metabolic activation: N-methyl-N'-nitro-N-nitrosoguanidine and benzo(a)pyrene-4,5-oxide for all strains
With metabolic activation: 3-methylcholanthrene, benzo(a)pyrene and 2-aminoanthracene for all strains
Evaluation criteria:
Positive results
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility of the result

Results and discussion

Test resultsopen allclose all
Species / strain:
other: S. typhimurium TA 100, TA 1537, TA 98
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity:
no, but tested up to precipitating concentrations
Remarks:
precipitation which was observed in concentrations >= 1000 µg/plate
Vehicle controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
other: S. typhimurium TA 100, TA 1537
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity:
other: precipitation was observed in concentrations >= 1000 µg/plate; cytotoxicity was obseved in TA100 in the same concentrations in one experiment.
Vehicle controls valid:
yes
Positive controls valid:
yes

Any other information on results incl. tables

Standard plate test (31.5 - 3000 µg/plate)
Strain Metabolic activation system mean revertants in Controls maximum revertant factor* dose dependency Assessment
TA 98 no 23 1.0 no negative
  yes (Aroclor 1254) 50 5.4 yes positive
TA 100 no 150 1.3 no negative
  yes (Aroclor 1254) 1st run 139 20.9 yes positive
  yes (Aroclor 1254) 2nd run 145 17.0 yes positive
  yes (Phenobarbital) 163 22.7 yes positive
  yes (b-Naphthaflavone) 140 12.0 yes positive
TA 1537 no 11 1.0 no negative
  yes (Aroclor 1254) 22 1.1 no negative
* in non-precipitating concentrations

Applicant's summary and conclusion