遺伝毒性試験・発癌性試験・発生毒性試験に関するパート３の改訂案

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Contents
Foreword
Introduction
1 Scope
2 Normative references
3 Definitions
4 Genotoxicity tests
5 Carcinogenicity tests
6 Reproductive toxicity tests
7 Test Report
Annex
A Flow chart
B Bibliography

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

International Standard ISO 10993-3 was prepared by Technical Committee ISO/TC 194, Biological evaluation of medical devices.

ISO 10993 consists of the following parts, under the general title Biological evaluation of medical devices:

- Part 1: Guidance on selection of tests
- Part 2: Animal welfare requirements
- Part 3: Tests for genotoxicity, carcinogenicity and reproductive toxicity
- Part 4: Selection of tests for interactions with blood
- Part 5: Tests for cytotoxicity: in vitro methods
- Part 6: Tests for local effects after implantation
- Part 7: Ethylene oxide sterilization residuals
- Part 9: Degradation of materials related to biological testing [Technical Report]
- Part 10: Tests for irritation and sensitization
- Part 11: Tests for system ic toxicity
- Part 12: Sample preparation and reference materials
- Part 13: Indentification and quantification of degradation products from polymers
- Part 14: Identification and quantification of degradation products from ceramics
- Part 15: Identification and quantification of degradation products from coated and uncoated metals and alloys
- Part 16: Toxicokinetic study design for degradation products and leachables
- Part 18: Material characterization

Future parts will deal with other relevant aspects of biological testing.
Annexes A and of this part of ISO 10993 are for information only.

Introduction

The basis for biocompatibility evaluation of medical devices is often empirical and driven by the relevant concerns for human safety. Not all test methods for the assessment of genotoxicity, carcinogenicity or reproductive toxicity are equally well developed, nor is their validity well established for the testing of medical devices.

Significant issues in test sample size and preparation, scientific understanding of disease processes and test validation can be cited as limitations of available methods. For example the biological significance of solid state carcinogenesis is poorly understood. It is expected that ongoing scientific and medical advances will alter our understanding and approaches to these important toxicity test methods. At the time the document was prepared, the test methods proposed were those most acceptable. Sound scientific alternatives to the proposed testing should be acceptable insofar as they address relevant matters of safety assessment.

In the selection of tests needed to evaluate a particular device, there is no substitute for a careful assessment of expected human uses and potential interactions of the device with various biological systems. These considerations will be particularly important in such areas as reproductive and developmental toxicology.

This part of ISO 10993 presents test methods for the detection of specific biological hazards, and therefore maximum test sensitivity is required. The interpretation of findings and implications for human health effects are beyond the scope of this part of ISO 10993. Because of the multitude of possible outcomes and the importance of such factors as extent of exposure, species differences and mechanical or physical considerations, risk assessment has to be performed on a case-by-case basis.

1 Scope

This part of ISO 10993 specifies tests for the following biological aspects:

- genotoxicity,
- carcinogenicity, and
- reproductive and developmental toxicity.

These are relevant in the biological evaluation of some categories of medical devices. Guidance on selection of tests is provided in ISO 10993-1. Where the need for the evaluation of the potential for genotoxicity, carcinogenicity or reproductive toxicity has been identified, they should be evaluated in accordance with this part of ISO 10993.

Most tests included in this part of the International Standard refer to the OECD guidelines for testing of chemicals. Reference to these tests is made by the term "OECD guideline(s)" followed by the appropriate test number(s).

At the time of testing, these tests are to be performed according to current OECD guidelines.

2 Normative references

The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.

ISO 10993-1:1997 Biological evaluation of medical devices - Part 1: Selection of tests
ISO 10993-2:1992 Biological evaluation of medical devices - Part 2: Animal welfare requirements
ISO 10993-6: 1994 Biological evaluation of medical devices - Part 6: Tests for local effects after implantation
ISO 10993-12: 1996 Biological evaluation of medical devices - Part 12: Sample preparation and reference materials

OECD Guidelines for testing of chemicals - Selected assays
- In vitro genotoxicity tests
471 Genetic Toxicology: Salmonella typhimurium, Reverse Mutation Assay.
472 Genetic Toxicology: Escherichia coli, Reverse Mutation Assay.
473 Genetic Toxicology: In vitro Mamalian Cytogenetic Test.
476 Genetic Toxicology: In vitro Mammalian Cell Gene Mutation Test.
479 Genetic Toxicology: In vitro Sister Chromatid Exchange Assay in Mammalian Cells.
480 Genetic Toxicology: Saccharomyces cerevisiae, Mitotic Recombination Assay.
481 Genetic Toxicology: Saccharomyces cerevisiae, Mitotic Recombination Assay.
482 Genetic Toxicology: DNA Damage and Repair/Unscheduled DNA Synthesis in Mammalian Cells In vitro.
XXX OECD draft Guideline "DNA Damage and Repair/unscheduled DNA synthesis in mammalian liver cells in vivo
- In vivo genotoxicity tests
474 Genetic Toxicology: Micronucleus Test.
475 Genetic Toxicology: in vivo Mammalian bone Marrow Cytogenetic Test - Chromosomal Analysis.
478 Genetic Toxicology: Rodent Dominant Lethal Test.
483 Genetic Toxicology: Mammalian Germ-Cell Cytogenetic Assay.
484 Genetic Toxicology: Mouse Spot Test.
485 Genetic Toxicology: Mouse Heritable Translocation Assay.
- Carcinogenicity tests
451 Carcinogenicity Studies.
453 Combined Chronic Toxicity/Carcinogenicity Studies.
- Reproductive toxicity tests
414 Teratogenicity.
415 One-Generation Reproduction Toxicity Study.
421 Reproduction/Developmental Toxicity Screening Test

Rules Governing Medicinal Products in the European Community. Volume 3. Guidelines on the Quality, Safety and Efficacy of Medicinal Products for Human Use. Commission of the European Community 1989. ISBN 92-825-9619-2.

3 Definitions

For the purposes of this part of ISO 10993, the definitions given in ISO 10993-1 and the following definitions apply.

3.1 genotoxicity test: Test that applies mammalian or non-mammalian cells, bacteria, yeasts or fungi to determine whether gene mutations, changes in chromosome structure, or other DNA or gene changes are caused by the test materials, devices and/or extracts from materials.

NOTE Tests on whole animals may also address these endpoints.

3.2 carcinogenicity test: Test to determine the tumorigenic potential of devices, materials, and/or extracts to either a single or multiple exposures over a period of the total life-span of the test animal.

NOTE These tests may be designed to examine both chronic toxicity and tumorigenicity in a single experimental study.

3.3 reproductive and developmental toxicity tests: Tests to evaluate the potential effects of devices, materials, and/or extracts on reproductive function, embryonic development (teratogenicity), and prenatal and early postnatal development.

3.4 maximum irnplantable dose (MID): Maximum amount of implant material (dose) that a test animal can tolerate without any adverse physical or mechanical effects.

NOTE To avoid unnecessary morbidity in animals on a long-term test, preliminary testing may be necessary.

3.5 energy-depositing device: Device intended to exert its therapeutic or diagnostic effect by the absorption of electromagnetic, ionic or ultrasonic radiation.

NOTE This does not include devices which deliver simple electrical current, such as electrocautery devices, pacemakers or functional electrical stimulators.

4 Genotoxicity tests

4.1 General

When the genetic toxicity of a medical device has to be experimentally assessed, a series of in vitro tests shall be used. This series shall include at least three assays. At least two of these should preferably use mammalian cells as a target. The tests should preferably cover the three levels of genotoxic effects: DNA effects, gene mutations and chromosomal aberations.

In vivo testing on animals shall only be carried out in accordance with subclause 4.1 of ISO 10993-2.

Medical devices shall be tested for genotoxicity as specified in ISO 10993-1, except those made only from materials known to show no genotoxicity, when, moreover, all major components of extracts can be identified by suitable analytical methods and have been shown to have no genetic toxicity (see also table I of ISO 10993-1).

4.2 Sample preparation

Any material or device shall be in its "ready-to-use" form (i.e. as a final product) prior to any extraction or test procedure. Sample preparation shall be in accordance with ISO 10993-12. Tests shall be performed either on extracts or the dissolved material using appropriate media.

Where meaningful, two appropriate extractants shall be used, one of which is a physiological medium, the second a solvent such as dimethylsulfoxide (DMSO), which is reasonably compatible with the test system.

WARNING - DMSO is known to be cytotoxic in selected assay systems at greater than 5 g/l concentrations of aqueous solvent.

4.3 Test methods

4.3.1 In vitro genotoxicity

Test methods shall normally be chosen from the OECD Guidelines for testing of chemicals: 471, 472, 473, 476, 479, 480, 481 and 482.

NOTE Some devices incorporate substances designed to have an effect on cells, e.g. antibiotics or antiseptics that are designed to incorporate an effect on cells.

4.3.2 In vivo genotoxicity

If scientifically indicated or in vitro test results indicate potential genotoxicity, then in vivo genotoxicity tests shall be undertaken. Test methods shall normally be chosen from the OECD Guidelines for testing of chemicals: 474, 475, 478, 483, 484 and 485.

NOTE Recently transgenic animal test systems are being developed for genotoxicity testing. These tests may prove valuable for implant testing but their use had not been validated at the time of publication of this International Standard. References on test systems employing transgenic animals are given in A.1.

4.4 Test strategy

4.4.1 Genotoxicity testing shall begin with the following three in vitro endpoints:

1. a bacterial assay for gene mutations and
Note: e.g. according to OECD Guideline 471 or 472
2. a test for gene mutation in mammalian cells and
Note: e.g. according to OECD Guideline 476
3. a test for clastogenicity in mammalian cells and
Note: e.g. according to OECD Guideline 473.

The performance of only one single test is not sufficient for detecting all genotoxic carcinogens.

When all results are negative further testing is not necessary.

In the event of positive in vitro results either the lack of in vivo mutagenic potential should be established on the evaluation of biological safety or the evaluation of biological safety should be based on the assumption that the compound is mutagenic.

Note: Additional guidance is given in ICH [39].

4.2.2 If the in vitro clastogenicity test is positive, an in vivo test using somatic cells shall be performed. Use one of the following test systems:

1. metaphase analysis in rodent bone marrow according to OECD Guideline 475 or
2. micronucleus test in rodents according to OECD 474.

If one of the in vitro gene mutation tests is positive one of the following tests should be conducted:
1. ex vivo test to investigate unscheduled DNA synthesis according to OECD draft
Guideline DNA Damage and Repair/Unscheduled DNA synthesis in mammalian liver
cells in vivo or
2. a mouse spot test according to OECD Guideline 484.
Other test systems concerning genotoxicity can be performed in order to obtain additional information.

5 Carcinogenicity tests
5. 1 General
Carcinogenicity tests shall be undertaken as indicated in ISO 10993-1.
Situations suggesting the need for carcinogenicity testing may include the following:

a) resorbable materials and devices, unless there are significant and adequate data on human use or exposure;
b) materials and devices where positive results have been obtained in genetic toxicity testing on mammalian cells;
c) materials and devices introduced in the body and/or its cavities with a permanent or cumulative contact of 30 days or longer, except when significant and adequate human-use history is available.

In those cases where carcinogenicity testing is required but no effects have occurred in genotoxicity tests, clinical testing may be performed concurrently with carcinogenicity testing.

Where implantation does not represent the most appropriate route of exposure, scientifically justified alternatives should be considered.

5.2 Sample preparation

Sample preparation shall be in accordance with ISO 10993-12. Whenever possible the device shall be tested in its "ready-to-use" form. Otherwise a suitably formed implant in accordance with ISO 10993- 6 shall be made of the test material, with appropriate consideration of potential solid state carcinogenicity (Oppenheimer effect, see annex A.3, [15].

5.3 Test methods

Carcinogenicity tests for medical devices are only performed as implantation tests. Carcinogenicity tests shall be performed in accordance with OECD Guidelines 451 or 453 after suitable modifications for implantable materials. Implantation shall be performed according to ISO 10993-6.

There will ordinarily be two dose levels, the maximum implantable dose (MID), and a fraction thereof (usually one half of the MID). The negative controls will generally include polyethylene implants or other materials whose lack of carcinogenic potential is documented in a comparable form and shape.

In carcinogenicity testing on rodents, the maximum implantable dose (MID) of a material or device should be applied. Where possible, this dose should be expressed as multiple of the worst case human exposure in milligrams per kilogram.

Tissues evaluated should include the implantation site and adjacent tissues.

NOTE 1 Suitable cell transformation systems may be used for carcinogenicity prescreening. Cell transformation tests have so far not been subject to International Standards or national standards. References on cell transformation test systems are given in A.2.

NOTE 2 See Official Journal of the European Communities L 133/73 from 30.5.1988 for In vitro-cell transformation test.

NOTE 3 There is also some evidence that two-step cell transformation assays can detect carcinogens which are non-genotoxic, but it is at this time not possible to conclude that all non- genotoxic carcinogens can be detected by cell transformation assays.

Therefore, carcinogenicity tests have to be performed as lifetime studies in vivo on at least one appropriate rodent species.

5.4 Test strategy

5.4.1 When according to ISO 10993-1 a chronic toxicity and carcinogenicity study shall be considered and it is determined that testing is necessary testing should be carried out according to OECD Guideline 453.

5.4.2 When according to ISO 10993-1 only a carcinogenicity study shall be considered and it is determined that testing is necessary testing should be carried out according to OECD 451.

NOTE: Information about a standard guide for performance of a lifetime study for the tumorigenic potential of implant material is given in [40] ASTM F 1439-39.

5.4.3 One animal species is sufficient for testing. The choice of this species shall be justified and documented

6 Reproductive toxicity tests

6.1 General

Reproductive toxicity tests should normally be considered for the following:

a) intrauterine devices (lUDs), or any other long-term contact devices likely to come into direct contact with reproductive tissues or the embryo/foe/us;

b) energy-depositing devices;
c) resorbable or leachable materials and devices.

There is no need for the testing of resorbable devices or devices containing leachable moieties where there is adequate and reassuring data from absorption, metabolism, distribution and on the reproductive toxicity of all major components identified in extracts of materials or devices.

6.2 Sample preparation
Sample preparation shall be in accordance with ISO 10993-12.
In the case of energy-depositing devices, whole-body irradiation of the animals with a multiple of the dose to be expected in humans should be applied.

When possible, IUDs, resorbable devices or devices containing leachable moieties shall be tested in their "ready-to-use" form. Otherwise a suitably formed implant shall be made of the test material.

The maximum implantable dose (MID) of a material or device should be applied. Where possible this dose should be expresse as a multiple of the worst case human exposure (in milligrams per kilogram).

6.3 Test methods

Assessment of effects on this first generation (f1) should be made according to absorption-kineric data and OECD Guidelines 414, 415 and 421. As the OECD guidelines were not intended for implantable devices the following modifications shall be considered:

- dose (in the case of energy-depositing devices),
- route of application,
- exposure time (elevated blood levels during organogenesis when possible).

NOTE Depending on intended human use and material characteristics, pert-/post-natal studies may be indicated (see also Rules Governing Medicinal Products in the European Community. Volume 3).

If information derived from other tests indicates potential effects on the male reproduction system, then appropriate tests for male reproductive toxicity shall be conducted.

NOTE Recently, in vitro reproductive test systems have been developed. They may be useful as a prescreening test method for reproductive toxicity. References to in vitro reproductive test systems are included in A.4.

6.4 Test strategy
When testing is required this shall be according to OECD 414 and 415.

7 Test report
The test report shall include details of the following documentation, where relevant
a) description of material and/or device including intended use (e.g. chemical composition, processing, conditioning and surface treatment);
b) description of test methods, test conditions, test materials, procedures;
c) description of analytical methods including quantification limits;
d) statement of compliance to appropriate good laboratory practices
e) summery of results
f) statistical methods
g) interpretation and discussion of results
Further details about the required test report are given in the respective OECD guidelines.

Annex A
(informative)

A. 1 Literature on transgenic animals

[1] KOHLER, SW., PROVOST, GS., KRETZ, PL., DYCAICO, MI., SORGE, JA. And SHORT, JM. Development of a short-term in vitro mutagenesis assay: the effect of methylation on the recovery of a lambda phage shuttle vector from transgenic mice. Nucleic Acid Research. 1990, vol. 18, p. 3007-3013.

[2] SHORT, JM., KOHLER, SW. And PROVOST, GS. The use of lambda phage shuttle vectors in transgenic mice for development of a short term mutagenicity assay. In Mutation and the environment. Wiley-Liss: New York, 1990. P. 355-367.

A.2 Literature on cell transformation assays

[3] Advances in Modern Environment Toxicology, Vol. 1. Mammalian Cell Transformation by Chemical Carcinogens. N. Mishra, V. Dunkel, and M. Mehlman (eds). Senate Press: Princeton Junction (New Jersey, 08550), 1981.

[4] Transformation Assays of Established Cell Lines: Mechanisms and Application. T. Kakunaga and H. Yamasaki (eds). Proceedings of a Workshop Organized by IARC in Collaboration with the US National Cancer Institute and the US Environmental Protection Agency, Lyon 15-17 Feb. 1984. IARC Scientific Publication No. 67.

[5] BARRETT, JC., OHSHIMURA, M., TANAKA, N. And TSUTSUI, T. Genetic and Epigenetic Mechanisms of Presumed Nongenotoxic Carcinogens. In Banbury Report 25: Nongenotoxic Mechanisms in Carcinogenesis, 1987, p. 311- 324.

[6] OSHIMURA, M., HESTERBERG, TOO., TSUTSUI, T. And BARRETT, JC. Correlation of Asbestos-induced Cytogenetic Effects with Cell Transformation of Syran Hamster Embryo Cells in Culture. Cancer Res. Nov. 1984, vol. 44, p. 5017-5022.

[7] BARRETT, JC., OSHIMURA, M., TANAKA, N. And TSUTSUI, T. Role of Aneuploidy in Early and late Stages of Neoplastic Progression of Syrian Hamster Embryo Cells in Culture. In Aneuploidy. Wicki L. Dellargo, Peter E. Voytek and Alexander Hollaender (eds). Plenum Publishing, 1985.

[8] FITZGERALD, DJ. And YAMASAKI, H. Tumor promotion: models and assay systems. Teratogenesis Carcinog. Mutagen., 1990, vol. 10, No. 2, p. 89-102.

[9] KUROKI, T. And MATSUSHIMA, T. Performance of short-term tests for detection of human carcinogens. Mutagenesis, 1987, vol. 2, No. 1, p. 33-7.

[10] RAY VA., KIER, LD., KANNAN, KL., HAAS, RT., AULETTA, AK., WASSOM, IS. NESNOW, S. And WATERS, MD. An approach to identifying specialized batteries of bioassays for specific classes of chemicals: class analysis using mutagenicity and carcinogenicity relationships and phylogenetic concordance and discordance patterns. 1. Composition and analysis of the overall data base. A report of phase II of the U.S. Environmental Protection Agency Gene-Tox Program. Mutat Res, 1987, vol. 3, p. 197241.

[11] DUNKEL, VD., SCHECHTMAN, LM., TU, AS., SIVAK, A., LUBET, RA. And CAMERON, TP. Interlaboratory evaluation of the C3H/1OT1/2 cell transformation assay. Environ. Mol. Mutagen., 1988, vol. 12, No. 1, p. 12-31.

[12] JONES, CA., HUBERMAN, E:, CALLAHAM, MF., TU, A., HALLOWEEN, W., PALLOTA, S., SIVAK, A., LUBET, RA., AVERY, MD., KOURI, RE., SPALDING, J. And TENNANT, RW. An interlaboratory evaluation of the Syrian hamster embryo cell transformation assay using eighteen coded chemicals. Toxicology in vitro, 1988, vol.2, No. 2, p. 103- 116.

A.3 Literature on genotoxicity and carcinogenicity testing

[13] Department of Health. Guidelines for the testing of chemicals for mutagenicity. Londong: HMSO, 1989. (Report on Health and Social Security Subjects No. 35).

[14] Department of Health. Guidelines for the evaluation of chemicals for carcinogenicity. London: HMSO, 1992. (Report on Health and Social Security Subjects No. 42).

[15] OPPENHEIMER, BS., OPPENHEIMER, ET. And STOUT, AP. Sarcomas induced in rats by implanting cellophane. Proc. Soc. Exp. Biol. Med., 1948, vol. 67, No. 33.

[16] BRAND, KG., JOHNSON, KH and BUON, LC. Foreign Body, Tumorgenesis CRC Crit. Rev. In Toxicology, October 1976, p. 353.

[17] BRAND, L. And BRAND, KG. Testing of Implant Materials for Foreign Body Carcinogenesis. In Biomaterials, 1980, p. 819. G.D. Winter, D.F. Gibbons, H. Plenk Jr. (Eds). Advances in Biomaterials, vol. 3. New YorkL. J. Wiley, 1982.

[18] Biological Bases for Interspecies Extrapolation of Carcinogenicity Data. Hill TA., Wands, RC., Leukroth RW. Jr. (eds). (Prepared for the Center for Food Safety and Applied Nutrition, Food and Drug Administration, Department of Health and Human Services, Washington, D.C.) July 1986, Bethesda (MD): Life Science Research Office, Federation of American Societies for Experimental Biology.

[19] National Toxicology Program Report of the BTP Ad Hoc Panel on Chemical Carcinogenesis Testing and Evaluation, August 1984, Board of Scientific Counselors.

A.4 Literature on reproductive toxicity testing

[20] 1990 Guideline for toxicity studies of drugs manual, Chapter 4: Reproductive and developmental toxicity studies. First edition. Editorial Supervision by New Drugs Division, Pharmaceutical Affairs Bureau, Ministry of Health and Welfare, Yakuji Nippo Ltd.

[21] Gabrielson, JL. and LARSSON, KS. Proposal for improving risk assessment in reproductive toxicology. Pharmacology & Toxicology, 1990, vol. 66, p. 10-17.

[22] BARRACH, HJ. and NEUBERT, D. Significance of Organ Culture Techniques for Evaluation of Prenatal Toxicity. Archives of Toxicology, 1980, vol. 45, p. 161-187.

[23] NEUBERT, D., BLANKENBURG, G., CHAHOUD, I., FRANZ, G., HERKEN, R., KASTNER, M., KLUG, S., KROGER, 1., KROWKE, R., LEWANDOWSKI, C., MERKER, HJ. And SCHULZ, T. Results of in Vivo and in Vitro Studies for Assessing Prenatal Toxicity. Environmental Health Perspectives, 1986, vol. 70, p. 89-103.

[24] SADLER, TOO., HORTON, WE. And WARNER, CW. Whole Embryo Culture: A Screening Technique for Teratogens? Teratogenesis, Carcinogenesis, and Mutagenesis, 1982, vol. 2, p. 243-253.

[25] FANTEL, AG. Culture of Whole Rodent Embryos in Teratogen Screening. Terarogenesis, Carcinogenesis, and Mutagenesis, 1982, vol. 2, p. 231-253.

[26] KIMMEL, GL., SMITH, K., KOCHHAR, DW. And PRATT, RM. Overview of in Vitro Teratogenicity Testing: Aspects of Validation and Application to Screening. Teratogenesis, Carcinogenesis, and Mutagenesis, 1982, vol. 2, p. 221-229.

[27] Culture Techniques, Applicability for Studies on Prenatal Differentiation and Toxicity. D. Neubert and HJ Merker (eds.). Berlin: Walter de Gruyter, 1981.

[28] In Vitro Methods in Developmental Toxicology: Use in Defining Mechanisms and Risk Parameters. GL. Kimmel and DM. Kochhar (eds.). Boca Raton (Florida): CRC Press, 1990.

[29] In Vitro Embryotoxicity and Teratogenicity Tests. F. Homburger and AH. Goldberg (eds.). Concepts in Toxicology, vol. 3. Basel: KARGER, 1985.

[30] BRENT, RL. Predicting Teratogenic and Reproductive Risks in Humans from Exposure to Various Environmental Agents Using In Vitro Techniques and In Vivo Animal Studies. Cong. Anom., 1988, vol. 28 (Suppl.), S41-S55.

[31] TSUCHIYA, T., NAKAMURA, A., IIO, T. And TAKAHASI, A. Species Differences between Rats and Mice in the Teratogenic Action of Ethylenethiourea: In Vivo/In vitro Tests and Teratogenic Activity of Sera Using an Embryonic Cell Differentiation System. Toxicology and Applied Pharmacology, 1991, vol. 109, p. 1-6.

[32] TSUCHIYA, T., BURGIN, H., TSUCHIYA, M., WINTERNITZ, P. and KISTLER, A. Embryolethality of new herbicides is not detected by the micromass teratogen tests. Arch. Toxicol, 1991, vol. 65, p. 145-149.

[33] KISTLER, A., TSUCHIYA, T., TSUCHIYA, M. And KLAUS, M. Teratogenicity of arotinoids (retinoids) in vivo and in vitro. Arch. Toxicol., 1990, vol. 64, p. 616-622.

[34] TSUCHIYA, T., TAKAHASHI, A., ASADA, S., TAKAKUBO, F., OHSUMI- YAMASHITA, N. And ETO, K. Comparative Studies of Embryotoxic Action of Ethylenethiourea in Rat Whole Embryo and Embryonic Cell Culture. Teratology, 1991, vol. 43, p. 319-324.

[35] FLINT, OP. An in vitro test for teratogens: its practical application. Fd. Chem. Toxic., 1986, vol. 24, Nos. 6/7, p. 627-631.

[36] SCHMID, BP. And CICUREL, L. Application of the post-implantation rat embry culture system to in vitro teratogenicity testing. Fd. Chem. Toxic., 1986, vol. 24, Nos. 6/7, p. 623-626.

[37] Report of the in vitro teratology task force, Organized by the Devision of Toxicology, Office of Toxicological Sciences, Center for Food Safety and Applied Nutrition, Food and Drug Administration. Environmental Health Perspectives, 1987, vol. 72, p. 200235.

[38] BASS, R., ULBRICH, B., HILDEBRANDT, AG., WEISSINGER, I., DOI, O., BAEDER, C., EUMERO, S., HARADA, Y., LEHMANN, H., MANSON, J., NEUBERT, D., OMORI, Y., PALMER, A. SULLIVAN, F., TAKAYAMA, S. And TANIMUTA, T. Draft guideline on detection of toxicity to reproduction for medical products. Adverse Drug React. Toxicol. Rev., 1991, vol. 9, No. 3, p. 127-141.

[39] ICH (International Conference on Harmonisation of technical requirements for Registration of Pharmaceuticals for human use); Harmonized Tripartite Guideline (Draft), Guidance on specific aspects of regulatory genotoxicity tests for pharmaceuticals.

[40] ASTM F 1439-39 Standard guide for performance of lifetime bioassay for the tumorgenic potential of implant materials