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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
Study period:
1994-05-31 to 1994-06-13
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Version / remarks:
dated September 1, 1988
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: crystalline

Method

Target gene:
histidine operon
Species / strainopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
Rat liver S9 mix (phenobarbital/5,6-benzoflavon induced)
Species / strain:
E. coli WP2 uvr A
Additional strain characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
Rat liver S9 mix (phenobarbital/5,6-benzoflavon induced)
Test concentrations with justification for top dose:
313, 625, 1250, 2500 and 5000 µg/plate
Vehicle:
- Vehicle used: distilled water
- Justification for choice of solvent/vehicle: Good solubility in water.
Controls
Negative controls:
yes
Solvent controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Without S9-mix: 2-(2-Furyl)-3-(5-nitro-2-fury)acrylamide (TA 100, TA98, WP2 uvrA), Sodium azide (TA1535), 2-methoxy-6-chloro-9-[3-(2-chloroethyl)-aminoprpylamino]acridin (TA1537); With S9 mix: 2-Aminoanthracene (all strains)
Details on test system and conditions:
METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 min at 37°C
- Exposure duration: 48 h at 37°C

NUMBER OF REPLICATIONS: 2

NUMBER OF INDIVIDUAL EXPERIMENTS: 1

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
The test substance is judged to be positive, when the number of revertant colonies is more than twice of the negative control, and the dose relationship and the reproducibility are obtained.
Statistics:
no statistical analysis

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
yes
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
yes
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Additional information on results:
The results showed that the number of revertant colonies was less than twice of the negative control for all strains at any dose level with or wothout metabolic activation. The groth inhibition was observed in all strains at 5000 µg/plate. The positive controls showed a distinct increase of revertant colonies, and the positive controls and the negative controls were within a range of the background data of the laboratory. There were no fluctuations wich might have affected the test results because the sterility test confirmed the absence of micro organisms.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Cesium hydroxide was judged to have no reverse mutagenic potenial in Ames test with and without metabolic activation.
Executive summary:

The reverse mutation test with cesium hydroxide was performed on Salmonella typhimurium strains TA100, TA1535, TA98, TA1537, and Escherichia coli strain WP2 uvrA using the pre-incubation method with and without metabolic activation up to a limit concentration of 5000 µg/plate.

The results showed that the number of revertant colonies was less than twice of the negative control for all strains at any dose level with or without metabolic activation. The growth inhibition was observed in all strains at 5000 µg/plate. The positive controls showed a distinct increase of revertant colonies, and the positive controls and the negative controls were within a range of the background data of the laboratory. There were no fluctuations wich might have affected the test results because the sterility test confirmed the absence of micro organisms.

In conclusion, cesium hydroxide was judged to have no reverse mutagenic potenial under the conditions tested.