Caesium hydroxide

Genetic toxicity: in vitro

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 for cross-reference:

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

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

Test material information

Constituent 1

Reference substance name:

Caesium hydroxide

EC Number:

244-344-1

EC Name:

Caesium hydroxide

Cas Number:

21351-79-1

Molecular formula:

CsHO

IUPAC Name:

caesium hydroxide

Constituent 2

Reference substance name:

Cesium hydroxide

IUPAC Name:

Cesium hydroxide

Test material form:

solid: crystalline

Method

Target gene:

histidine operon

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type 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 / solvent:

- Vehicle used: distilled water
- Justification for choice of solvent/vehicle: Good solubility in water.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle 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 experimental 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 results

Test results 1

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

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.

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

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.