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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP status unknown, tested according to standard NTP methodology. Minor restrictions in reporting but otherwise adequate for assessment. Not all OECD required tester strains used, but main ones covered.

Data source

Reference
Reference Type:
publication
Title:
Genetic Toxicology - Salmonella (297396)
Author:
National Toxicology Program
Year:
1993
Bibliographic source:
Internet link. http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm

Materials and methods

Test guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
NTP Standard Protocol
Deviations:
yes
Remarks:
Not all OECD required tester strains used, but main ones covered.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
Histidine gene
Species / strain
Species / strain / cell type:
other: Salmonella strains TA1535, TA100, TA97 and TA98
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 and hamster liver S9
Test concentrations with justification for top dose:
0, 0.001, 0.002, 0.007, 0.013 and 0.027 µg/plate
Vehicle / solvent:
No data
Controls
Untreated negative controls:
yes
Positive controls:
yes
Positive control substance:
other: sodium azide, 9-aminoacridine, 2-nitrofluorene or 4-nitro-o-phenylenediamine, 2-aminoanthracene
Details on test system and experimental conditions:
The plate tests were conducted within a sealed dessicator (gas chamber) for exposure to gaseous substances.
Evaluation criteria:
A positive response was defined as a reproducible, dose-related increase in histidine-independent (revertant) colonies in any one strain/activation combination. An equivocal response was defined as an increase in revertants that is not dose related, is not reproducible, or is not of sufficient magnitude to support a determination of mutagenicity. A negative response was obtained when no increase in revertant colonies is observed following chemical treatment. There was no minimum percentage or fold increase required for a chemical to be judged positive or weakly positive.

Results and discussion

Test results
Species / strain:
S. typhimurium, other: Salmonella strains TA1535, TA100, TA97 and TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Cytotoxicity was observed (reduced numbers of colonies) at the higher dose levels in some tester strains in both the absence and presence of S9.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with metabolic activation both rat and hamster S9
negative without metabolic activation

Methane was Ames negative in all of the strains tested both with and without metabolic activation
Executive summary:

Methane was Ames negative in all of the strains tested both with and without metabolic activation