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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study has been assessed for the use in a category approach. According to the methodology and to the extent of available details, the study has been judged as reliable with restrictions.

Data source

Reference
Reference Type:
publication
Title:
MICRONUCLEUS TESTS IN MICE ON 39 FOOD ADDITIVES AND EIGHT MISCELLANEOUS CHEMICALS
Author:
HAYASHI M, KISHI M, SOFUNI T, ISHIDATE M JR
Year:
1988
Bibliographic source:
Food Chem Toxicol. 26(6): 487-500

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
Remarks:
No significant deviation.
GLP compliance:
not specified
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in the paper): sodium d-tartrate (CAS 868-18-8)
- degree of purity 99.5%

Test animals

Species:
mouse
Strain:
other: ddY
Sex:
male
Details on test animals and environmental conditions:
Animals were fed with pellets CE-2 and water ad libitum.

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
saline solution
Duration of treatment / exposure:
1st study: single intraperitoneal administration was performed.
2nd study: multiple administrations; four injections with 24-hr intervals between them were performed.
Frequency of treatment:
1st study: single intraperitoneal administration was performed.
2nd study: multiple administrations; four injections with 24-hr intervals between them were performed.
Post exposure period:
Sampling were performed after 26 hours from the last injection.
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
900 mg/Kg
Basis:
other: single dose injected by i.p. route
Remarks:
Doses / Concentrations:
2700 mg/Kg
Basis:
other: single dose injected by i.p. route
Remarks:
Doses / Concentrations:
1800 mg/Kg
Basis:
other: single dose injected by i.p. route
Remarks:
Doses / Concentrations:
3600 mg/Kg
Basis:
other: single dose injected by i.p. route
Remarks:
Doses / Concentrations:
1000 mg/Kg
Basis:
other: doser level used in multiple administration study (2nd study)
No. of animals per sex per dose:
6 males per dose level.
6 males per negative control.
3 males per positive control.
Control animals:
yes, concurrent vehicle
Positive control(s):
Mitomicyn C (MMC) was used as positive control.

Examinations

Tissues and cell types examined:
The proportion of polychromatic erythrocytes (PCEs) among the total erythrocytes was also evaluated by observing 1000 erythrocytes on the same slide.
Statistics:
Before evaluating the test data statistically, the frequencies of MNPCEs in concurrent negative and positive control groups were compared with the control charts of historical data to confirm the technical validity of the experiment. To estimate the true spontaneous level, it should be more reliable to use historical control data instead of the results from concurrent controls which could fluctuate.
According to the historical negative control data accumulated separately in the two laboratories, the number of MNPCEs per mouse followed binomial distributions with P = 0.00200 and n = 1000.
A two-stage statistical procedure was used. In the first step of the procedure the frequency of MNPCEs in each treatment group was compared with the binomial distribution specified by historical control data from the laboratory where the test was performed. In the second step, the dose-response relationship was tested by the Cochran-Armitage trend test (Armitage, 1955; Cochran, 1954; Margolin & Risko, 1988). A positive result was recorded only when one or more treatment group(s) showed a statistically significant difference (P< 0.01) from the spontaneous level of MNPCEs and the trend test indicated a positive dose response (P < 0.05). This procedure was not applied to tests with multiple treatments which, in most cases, contained only one dose group. Such data were evaluated statistically using the first step only.
A Monte-Carlo simulation study showed that the probability of a type I error (the probability of a false positive), in this two-step procedure was, in general, closer to the nominal significance level (P= 0.01) than that of the usual conditional binomial test (Kastenbaum & Bowman, 1970) which has been widely used to evaluate micronucleus test data.
Similarly, this method was a more powerful method of analysis than the conditional binomial test. A detailed description of this statistical procedure will be reported separately.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
yes
Remarks:
Four males were died following single administration of 3600 mg/kg of the substance.
Vehicle controls valid:
yes
Negative controls valid:
not specified
Positive controls valid:
yes
Additional information on results:
The absence of genotoxicity (intended as frequencies of micronucleates PCEs) was observed togheter with a reduction of frequencies of PCEs which could be related to the capability of the substance of reaching the target (PCE).

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
The test substance was found negative following single and multiple administrations. Indeed, the substance does not showed a significant induction of micronuclei in this test when compared with negative control and historical control data.