1 Birth Defects Monitoring Systems: Accomplishments and Goals.- 1. Introduction.- 2. Further Reasons for Registering Malformations.- 3. Fundamentals of Malformation Registration.- 3.1. Identifying Malformations.- 3.2. Reporting Malformations.- 3.3. Coding.- 3.4. Storage of Information.- 4. What Should Be Monitored?.- 4.1. Gross and Minor Malformations.- 4.2. Multiple Malformations.- 4.3. Background Information Needed.- 5. The Problem of Ascertainment.- 6. Size of Population Monitored.- 7. Properties of Monitoring Systems and Ascertainment Rates.- 8. Detection of Changes in Prevalence.- 9. Limitations and Benefits of Monitoring Systems.- References.- 2 What Is a Teratogen? Epidemiological Criteria.- 1. Introduction.- 2. Definition of a Teratogen.- 3. Criteria of Judgment in Epidemiology.- 3.1. Strength of Association.- 3.2. Specificity of Association.- 3.3. Consistency of Association.- 3.4. Coherence with Other Data—Clinical and Laboratory.- 4. Dealing with Doubt.- 4.1. Data Consisting Entirely of Case Reports.- 4.2. Doubt Raised by Inconsistency.- 4.3. Where Confounding Cannot Be Controlled.- 5. Raising the Alert.- 5.1. Assessment of Changes over Time.- 5.2. The Range of Outcomes.- 5.3. The Definitions of Outcomes to Be Monitored and Their Baseline Frequencies.- 5.4. The Strength of Association.- 5.5. The Frequency of Exposure in the Population.- 5.6. The Etiological Fraction.- 5.7. Statistical Methods.- 6. Conclusion.- References.- 3 Congenital Hydrocephalus in Mice and Man.- 1. Introduction.- 2. Teratology.- 2.1. Hereditary (Spontaneous) Hydrocephalus.- 2.2. Exogenous (Induced) Hydrocephalus.- 3. Discussion.- References.- 4 Congenital Defects of Domestic and Feral Animals.- 1. Introduction.- 2. Definitions.- 3. Nature and Effect.- 4. Frequency.- 5. Causes.- 5.1. Environmental Factors.- 5.2. Genetic Factors.- 6. Specific Defects.- 6.1. Skeletal.- 6.2. Joints.- 6.3. Muscular.- 6.4. Central Nervous System.- 6.5. Storage Diseases.- 6.6. Ocular.- 6.7. Skin.- 6.8. Hair.- 6.9. Cardiovascular.- 6.10. Respiratory.- 6.11. Digestive.- 6.12. Hepatic.- 6.13. Large Body Cavities.- 6.14. Urinary.- 6.15. Reproductive.- 6.16. Metabolic.- 6.17. Immunodeficiency.- 6.18. Defective Twinning.- 7. Conclusions.- References.- 5 Transplacental Exposure to Diethylstilbestrol.- 1. Introduction.- 2. Clinical Research.- 2.1. Lower Genital Tract Anomalies.- 2.2. Upper Genital Tract Anomalies.- 2.3. Hormones and Enzymes.- 2.4. Reproduction.- 2.5. Cancer.- 3. Animal Research.- 3.1. Issues.- 3.2. Animal Models.- 3.3. Critique of Models.- 3.4. Cytology.- 3.5. Metabolism.- 3.6. Superimposed Carcinogens.- 3.7. Second-Generation Effects.- 4. Mechanism of Transplacental Carcinogenesis.- 4.1. First Generation.- 4.2. Second Generation.- 4.3. Abnormal Histogenesis.- References.- 6 Hormones, Growth Factors, and Their Receptors in Normal and Abnormal Prenatal Development.- 1. Introduction.- 2. Steroids.- 2.1. Glucocorticoids.- 2.2. Glucocorticoid-Induced Cleft Palate.- 2.3. Glucocorticoid Receptors in Secondary Palate Development.- 2.4. H-2 Influence on Glucocorticoid-Induced Cleft Palate.- 2.5. Glucocorticoid Effects on the Development of the Secondary Palate.- 2.6. Estrogens.- 3. Growth Hormones and Factors.- 3.1. Insulin.- 3.2. Somatomedins.- 3.3. Epidermal and Nerve Growth Factor.- 3.4. Hormonal Influences Mediated by Cyclic Nucleotides.- 4. Dioxins and Their Receptors in Teratology.- 5. Benzodiazepine and Opiate Receptors.- 6. Summary and Conclusions.- References.- 7 Vertebrate Limb Morphogenesis: A Review of Normal Development in a Model Experimental System with Applications toward Understanding Abnormal Limb Formation.- 1. Introduction.- 2. The Apical Ectodermal Ridge.- 2.1. Promotion of Axial Growth.- 2.2. Maintenance of Limb Vasculature.- 2.3. Structural Organization.- 3. Mesoderm and Limb Patterns.- 3.1. Origin of Limb Mesenchymal Cells.- 3.2. Pattern Formation.- 4. Extracellular Matrix.- 4.1. Collagen.- 4.2. Proteoglycan.- 4.3. Fibronectin.- 4.4. Cell-Matrix Interaction.- 5. Cell Death.- 5.1. Patterns of Necrosis.- 5.2. Pattern Variation.- 6. Limb Mutants.- 6.1. Limbless.- 6.2. Wingless.- 6.3. Talpid.- 6.4. Eudiplopodia.- 6.5. Stumpy.- 6.6. BrachypodismH.- 7. Dysmorphogenesis.- 7.1. Amelia.- 7.2. Hemimelia.- 7.3. Phocomelia.- 7.4. Syndactyly and Polydactyly.- 8. Summary.- References.- 8 Teratogenicity of Experimental and Occupational Exposure to Industrial Chemicals.- 1. Introduction.- 2. Alcohols (Ethanol).- 3. Aldehydes.- 3.1. Formaldehyde.- 3.2. Acetaldehyde.- 4. Heavy Metals.- 4.1. Lead.- 4.2. Mercury and Organic Mercury Compounds.- 4.3. Cadmium.- 5. Halogenated Hydrocarbons (Chlorinated Solvents).- 5.1. Chloroform.- 5.2. Carbon Tetrachloride.- 5.3. Trichloroethylene.- 5.4. Perchloroethylene.- 5.5. Methyl Chloride.- 5.6. Methylene Chloride.- 5.7. Methylchloroform.- 5.8. Ethylene Dibromide.- 5.9. Ethylene Dichloride.- 6. Ketones.- 6.1. Acetone.- 6.2. Methyl Ethyl Ketone.- 7. Organic Solvents.- 7.1. Benzene.- 7.2. Toluene.- 7.3. Xylene.- 7.4. Ethylene Glycol Monomethyl Ether and Ethylene Glycol Monoethyl Ether.- 8. Plastics and Related Chemicals.- 8.1. Styrene.- 8.2. Vinyl Chloride.- 8.3. Vinylidene Chloride.- 8.4. Acrylonitrile.- 8.5. Acrylamide.- 8.6. Epichlorohydrin.- 8.7. Phthalates.- 8.8. Acrylates.- 8.9. Urethan.- 8.10. Chloroprene.- 8.11. Alkylene Oxides.- 9. Chlorobenzenes and Carbon Monoxide.- 9.1. Monochlorobenzene.- 9.2. o- and p-Dichlorobenzene.- 9.3. Tetrachlorobenzenes.- 9.4. Hexachlorobenzene.- 9.5. Carbon Monoxide.- 10. Discussion and Conclusions.- References.- 9 Critical Assessment of Genetic Effects of Ionizing Radiation on Pre- and Postnatal Development.- 1. Introduction.- 2. Prologue.- 3. The Human Experience.- 3.1. Diagnostic and Therapeutic Use of X-Rays and Radioactive Materials.- 3.2. Occupational Exposure.- 3.3. Geographic Areas with “High” Natural or Man-Made Background Exposures.- 3.4. The Offspring of A-Bomb Survivors.- 4. Permissible Exposures.- 5. Future Directions.- 6. Glossary.- References.- 10 Adverse Effects in Humans and Animals of Prenatal Exposure to Selected Therapeutic Drugs and Estimation of Embryo-Fetal Sensitivity of Animals for Human Risk Assessment: A Review.- 1. Introduction.- 2. Aspirin and Salicylates.- 2.1. Human Studies.- 2.2. Animal Studies.- 2.3. Pharmacokinetics and Metabolism.- 2.4. Extrapolation of Hazards to Human Fetus.- 3. Progestational Agents.- 3.1. Progesterone and Hydroxyprogesterone.- 3.2. Testosterone and Its Derivatives.- 3.3. Progestogen and Estrogen.- 3.4. Diethylstilbestrol.- 4. Anticonvulsant Drugs.- 4.1. Human Studies.- 4.2. Animal Studies.- 5. Phenothiazines.- 5.1. Human Studies.- 5.2. Animal Studies.- 6. Meprobamate.- 6.1. Human Studies.- 6.2. Animal Studies.- 6.3. Extrapolation of Hazards to Human Fetus.- 7. Pregnancy Toxemia and Reserpine.- 7.1. Human Studies.- 7.2. Animal Studies.- 7.3. Extrapolation of Hazards to Human Fetus.- 8. Thalidomide.- 8.1. Human Studies.- 8.2. Animal Studies.- 8.3. Pharmacokinetics and Metabolism.- 8.4. Extrapolation of Hazards to Human Fetus.- 9. Isoniazid.- 9.1. Human Studies.- 9.2. Animal Studies.- 9.3. Extrapolation of Hazards to Human Fetus.- 10. Tetracyclines.- 10.1. Human Studies.- 10.2. Animal Studies.- 11. Aminopterin.- 11.1. Human Studies.- 11.2. Animal Studies.- 11.3. Extrapolation of Hazards to Human Fetus.- 12. Methotrexate.- 12.1. Human Studies.- 12.2. Animal Studies.- 12.3. Pharmacokinetics and Metabolism.- 12.4. Extrapolation of Hazards to Human Fetus.- 13. Fetal Sensitivity in Animals Relative to Humans: Conclusions.- 14. Summary.- References.