Teratological method

A selective compilation of papers on safety evaluation and regulation of chemicals, including the impact of regulations and improvement of methods, has been published as a book, edited by Homburger (ref. 13). Out of 34 papers, two are devoted directly to teratogens and address current in vivo reproductive toxicity and teratology methods, and new perspectives in tests for teratogenicity. 

Animal studies of the effect of PBB exposure on pregnancy have been carried out on the cow, monkey, mouse and rat. A number of these studies employed acceptable teratological methods to determine PBB teratogenicity (ref. 80, pp. 440ff). These are described in some detail in Barlow and Sullivan, and will be discussed only briefly here. When pregnant female mice were fed 200 ppm PBBs on days 4-16 and 8-16, the incidence of fetal mortality and resorption was greater for the 4-16 cohort, with reduced fetal body weight in the 8-16 cohort. Live litter size was also reduced at lOOppm in the 8-16 cohort. 

Schwetz et al." exposed rats and mice to 300 ppm tetrachloroethylene for 7 h/day on days 6-15 of pregnancy. The dams were killed just before term and the fetuses examined by acceptable teratological methods but results are given on a per litter basis only. The number of treated animals in each case was 17 and the number of controls (air exposed) 3 0 for both rat and mouse studies. 

Murray et al. exposed groups of 35-37 mice to 0 or 500 ppm benzene for 7 hr/day on days 6-15 of pregnancy. Acceptable teratological methods were used. There was no evidence of maternal toxicity. There were no effects on implants/dam, live fetuses/dam, resorptions/dam or malformation rates. Fetal body weight was significantly reduced and delayed ossification significantly increased in fetuses from the benzene group. 

Christian, M.S. and Hoberman, A.M. (1989). Current in vivo reproductive toxicity and developmental toxicity (teratology) test methods. In A Guide to General Toxicology, 2nd ed. (Marquis, J.A. and Hayes, A.W., Eds.). S. Karger, Basel, Switzerland, pp. 91-100. 

Wilson, J. (1965). Methods for administering agents and detecting malformations in experimental animals. In Teratology, Principles and Techniques (Wilson, J.G. and Warkany, J., Eds.). University of Chicago Press, pp. 262-277. 

Smithells RW, Sheppard S. Teratogenicity testing in humans a method demonstrating safety of Bendectin. Teratology 1978 17 31-6. 

Dietary administration is not recommended, except for materials of low toxicity and for which gavage administration is not practical. Rabbits generally have very variable food consumption, and dietary administration is not suitable. Inhalation dosing is appropriate for some substances both whole body and nose only exposure are possible for teratology studies (10) and it is recommended that the same exposure method is used as in previous toxicity studies. 

Ikegawa S et al (1992) Comparison of the alkaline solution method and Salewski s method in the usefulness for detecting implantation sites. Teratology 46 37B... 

Key words Vaccines, Developmental toxicology, DART, Teratology, Preclinical methods... 

Key words DART, Teratology, Fertility, Preclinical methods. Embryo-fetal development, Embryotoxicity. 

Gaylor DW (1978) Methods and concepts of biometrics applied to teratology. In Wilson JG, Fraser FC (eds) Handbook of teratology, vol I. Plenum, New York, pp 429-444... 

Holson RR, Paule MG, Scalzo FM ed. (1990) Methods in behavioral toxicology and teratology. Neurotoxicol Teratol, 12(5). 

Welsch F (1990) Short term methods of assessing developmental toxicity hazard. In alter H ed. Issues and reviews in teratology, Vol. 5. New York, Plenum Press, pp 115-153. 

Sample Volume <100 L, High Concentration Factors. Lyophiliza-tion is a feasible process for concentrating limited numbers of 50-100-L samples to relatively high degrees of concentration (e.g., 3000-fold to dryness). Thus, it is one method of choice for the preparation of samples for in vivo tests (including teratology tests). 

Adams J (1986) Methods in behavioral teratology. In Riley EP Vorhees CV eds. Handbook of behavioral teratology. New York, Plenum Press, pp 67-97. 

Buelke-Sam J Kimmel CA (1979) Development and standardization of screening methods for behavioural teratology. Teratology, 20 17-29. 

Gaylor, D. W. "Methods and Concepts of Biometrics Applied to Teratology" In "Handbook of Teratology 4 Research Procedures and Data Analysis" Wilson, J. G. Fraser, F. C., Eds. Plenum Press, New York, N. Y. 1978 Chap. 14. 

Maizlish NA, Parra G, Feo O Neurobehavioural evaluation of Venezuelan workers exposed to inorganic lead. Occup Environ Med 52 408-414, 1995 Mantere P, Hanninen H, Hernberg S Subclinical neurotoxic lead effects two-year follow-up studies with psychological test methods. Neurobehavioral Toxicology and Teratology 4 725-727, 1982... 

The recent discovery of high-level thallium pollution in the environment has focused attention on the teratogenicity (fetus malformation). For detailed investigations in this field a method is required which enables the quantitative detection of thallium in extremely small tissue samples (embryos, placenta tissues etc.) thus permitting to establish a correlation between measured values and teratological findings. Regarding the pharmacokinetics of thallium in a test animal (mouse) the first results obtained by FDMS have been reported . 

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