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11 Cards in this Set
- Front
- Back
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teratogen definition
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an exogenous agent inducing abnormalities of development- sensitive period between weeks 3 and 8 of gestation (all-or-none phenomenon), after that the deficits tend to be functional and not structural
including: drugs, viruses, radiation, hyperthermia, and maternal illnesses |
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Paternal teratogenesis
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1) induction of genetic damage in sperm
2) sperm acts as a physical carrier of the agent (i.e. in animals, cocaine injected into rats causes the pregnancies fostered by these rats to have birth defects) 3) seminal fluid transfer- agents found in the seminal fluid may be able to transfer teratogens Occupational risks= exposure to solvents- janitors, painters, printers, fire fighters |
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dose-response effects
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The greater the exposure during pregnancy the more severe the phenotypic effect
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prednisone birth defect
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cleft palate
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Identification of human teratogens
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Suspect, if after exposure there is:
1. Abrupt increase in defect 2. Distinct pattern of malformation 3. Coincidence of increase with an agent 4. Sufficient number of cases 5. Known exposure to agent in pregnancy 6. Absence of other factors |
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FDA’s Use-in-pregnancy Drug Rating
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Category A = controlled studies show NO risk
Category B = no evidence of risk in humans Category C = risk cannot be ruled out Category D = contraindicated in pregnancy (ex. thalidomide) |
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Thalidomide
Usage Defects |
used to relieve nausea and cause sedation (R enantomer only), anti-inflammatory for leprosy (must register with STEPS)
Mechanism- intercalates into guanine rich regions (ex. GC Box in promoters and regulatory regions) Defects (S enantomer only):bilateral limb reduction, defects in external ears, kidneys and heart permanently altered gene expression in these people- their kids will have birth defects too |
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Fetal alcohol syndrome
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most common cause of mental retardation and birth defects
Characteristic facial features, growth deficiency of prenatal onset, mental retardation *1-2 drinks/day deleterious to some fetuses *Binge drinking more harmful than steady drinking at particular times: Leads to neuronal apoptosis |
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Fetal alcohol effect (FAE)
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some but not all of the symptoms of FAS and attention deficit disorder
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Diethylstilbestrol (DES)
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Used to prevent miscarriages (actually causes them!)
Effects seen 20-30 years later: vaginal adenocarcinoma; also abnormalities of cervix and uterus genital abnormalities and noncancerous growth in males even grandchildren get genital abnormalities |
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Exogenous Retinoids (ex Acutane)
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Usage: Acne (Acutane) or psoriasis (Soriatane)
Defects: hydrocephaly, heart defects, small head, mental retardation, and craniofacial abnormalities *worse if combined with Alcohol |
