Registration Dossier

Diss Factsheets

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, minor restrictions in reporting but otherwise adequate for assessment.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
Principles of method if other than guideline:
Tested using a standard protocol: Galloway SM, Bloom AD, Resnick MA, Margolin BH, Nakamura F, Archer P, Zeiger E (1985): Development of a standard protocol for in vitro cytogenetic testing with Chinese hamster ovary cells: Comparison of results for 22 compounds in two laboratories. Environ Mutagen 7:1-51.
GLP compliance:
not specified
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium diethyldithiocarbamate
EC Number:
205-710-6
EC Name:
Sodium diethyldithiocarbamate
Cas Number:
148-18-5
Molecular formula:
C5H11NS2.Na
IUPAC Name:
sodium (diethylcarbamothioyl)sulfanide

Method

Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
- Source : Dr. Sheila Galloway (Litton Bionetics, Kensington, MD)
- Type and identity of media: McCoy's 5A (modified) medium (KC Biological, Lenexa, KS)
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes
- Growth and treatment conditions: Galloway SM, Bloom AD, Resnick MA, Margolin BH, Nakamura F, Archer P, Zeiger E (1985): Development of a standard protocol for in vitro cytogenetic testing with Chinese hamster ovary cells: Comparison of results for 22 compounds in two laboratories. Environ Mutagen 7:1-51.
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced S9 rat liver microsomal fraction (Microbiological Associates, Kensington, MD)
Test concentrations with justification for top dose:
Without metabolic activation, 1st experiment: 0.0; 0.1; 0.3 and 1.0 µg/ml;
With metabolic activation: 0.0; 15.2; 50.7 and 152 µg/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
- Stock solutions were prepared at 500 mg/ml, or at the limit of solubility, and diluted 1:100 in medium to obtain a high test concentration of 5 mg/ml
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

Without metabolic activation:
DURATION
- Exposure duration: 8 hours
- Fixation time (start of exposure up to fixation or harvest of cells): After 8 hours of exposure, cells are washed to remove the test chemical, and treated with colcemid (10E-6 M) for 2-2.5 hr before cell harvest.

With metabolic activation:
DURATION
- Exposure duration: 2 hours
- Incubation period: incubated at 37°C with medium for 8 hr.
- Fixation time (start of exposure up to fixation or harvest of cells): After incubation, colcemid was added and the cells were harvested 2 hr later.

STAIN (for cytogenetic assays): slides were stained in 5% Giemsa for 5 min

NUMBER OF REPLICATIONS: one

NUMBER OF CELLS EVALUATED: One hundred cells were scored for each of three concentrations

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index

OTHER EXAMINATIONS:
Cells were analyzed for the following categories of chromosomal aberrations: "Simple,"defined as chromatid gap, break, fragment, and deletion, chromosome gap and break, double minutes; "complex" rearrangements such as interstitial deletion, triradial, quadriradial, ring, dicentric chromosome; and "other," defined as pulverized chromosome, polyploid cell, or endoreduplicated cell. Chromatid and chromosome gaps were recorded but were not used for evaluation. The frequency of polyploid or endoreduplicated cells was only noted when it seemed excessive; however, these categories were never included in the totals for statistical analysis.
Statistics:
The statistical procedures for evaluation of test data are described in Galloway SM. Armstrong MA, Reuben C, Colman S, Brown C, Cannon AD. Bloom AD, Nakamura F, Ahmed M, Duk S, Rimpo J, Margolin BH, Resnick MA, Anderson B, Zeiger E (1987): Chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells: Evaluations of 108 chemicals. Environ Mol Mutagen l0(Suppl 10):1-175.

Results and discussion

Test results
Species / strain:
Chinese hamster Ovary (CHO)
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
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1. Results of chromosome aberration test with sodium diethyldithiocarbamate in the absence of metabolic activation.

Dose (μg/ml)

Cells

Percentage cells with aberrations

Total

Simple

Complex

0.0000

100

3.00

3.00

0.00

0.1000

100

1.00

1.00

0.00

0.3000

100

4.00

4.00

0.00

1.0000

100

0.00

0.00

0.00

Positive control (MMC) 5.000

50

72.00

46.00

48.00

Table 2. Results of chromosome aberration test with sodium diethyldithiocarbamate with metabolic activation.

Dose (μg/ml)

Cells

Percentage cells with aberrations

Total

Simple

Complex

0.0000

100

2.00

2.00

0.00

15.2000

100

6.00

5.00

1.00

50.7000

100

4.00

3.00

1.00

152.0000000

100

4.00

4.00

0.00

Positive control (CP) 50.0000

50

42.00

24.00

30.00

Applicant's summary and conclusion