Developmental Toxicology

Question 1

types of teratogens

Answer 1

maternal factors

drugs

infectious agents

physical agents

Question 2

TORCH agents

Answer 2

Toxoplasmosis

Syphilis

Rubella

Cytomegalovirus

Herpes

Question 3

teratogen

Answer 3

agents that generally have desirable effects on the viability of the embryo or its development

accounts for about 6-7% of malformations

Question 4

factors that determine teratogenic effects

Answer 4

nature of teratogen, timing and duration of exposure, and dose

Question 5

principles of developmental toxicology

Answer 5

teratogens act with specificity

teratogens demonstrate a dose-effect relationship

the effect that a teratogenic agent has on a developing fetus depends on the stage of development which the fetus is exposed

the genotype of the mother and the fetus influence susceptibility of teratogens

there are differences between species

Question 6

thalidomide

Answer 6

produces phocomelia

Question 7

phenytonin

Answer 7

produces nail and 5th finger hypoplasia

Question 8

trimethadione

Answer 8

produces cleft palate

Question 9

When do most teratogens have their effects?

Answer 9

during organogenesis, 2-8 weeks after conception

Question 10

epoxide hydrolase

Answer 10

an enzyme when deficient makes the fetus more susceptible to the teratogenic effects of phenytoin, resulting in fetal hydantoin syndrome

Question 11

What are the factors that affect how much of a teratogen a fetus is exposed to?

Answer 11

maternal dose

route of administration

factors affecting biodistribution in the mother

efficiency with which the drug crosses the placenta

fetal genotype

duration of exposure

Question 12

maternal factors that can lead to malformations

Answer 12

maternal diabetes mellitus, uncontrolled PKU

Question 13

maternal diabetes mellitus

Answer 13

causes a 3-fold increase in congenital malformations

risk appears to be inversely related to the extent of glycemic control

specific malformations are associated with DM such as caudal regression syndrome, spin and lower extremity malformations, congenital heart disease, retnal and CNS malformations

Question 14

uncontrolled maternal PKU

Answer 14

causes malformation in >90% of infants

defects include microcephaly, mental retardation, congenital heart defects

Question 15

Warfarin Embryopathy and Chondrodysplasia punctata (X-linked)

Answer 15

examples of phenocopies

symptoms for both include hypoplasia of nasal cartilage, shory distal phalanges, small naisls, chondroplasia punctata, and short stature

both caused by defects of arylsulfatase E