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24 Cards in this Set

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what is the difference between a teratogen and a mutagen?
mutagen - agent that causes mutations in a gene in either mother or father

teratogen - really must affect the mother, ie if father drinks alcohol this will not cause fetal alcohol syndrome
What is thalidomide?
treats leprosy

if taken between 21-35 days
after implantation causes limb reduction (symmetrical) heart defects cleft lip ear malformations and duodenal atresia
FDA rating of teratogenicity
class A
A - no risk
B - no human risk
c - unknown human risk
D - evidence of human risk
E - fetal risk outweighs any benefit to mother
looks like genetic abnormality but really was environmental

ie) Holt-Oram syndrome, maternal diabetes embryopathy, VATER association)

* V = Vertebral anomalies; and
* A = Anal atresia (no hole at the bottom end of the intestine);
* C = Cardiac defect, most often ventricular septal defect;
* TE = TracheoEsophageal fistula (communication between the esophagus and trachea) with esophageal atresia (part of the esophagus is not hollow);
* R = Renal (kidney) abnormalities; and
* L = Limb abnormalities, most often radial dysplasia (abnormal formation of the thumb or the radius bone in the forearm).
Maternal infections
Taxoplasmosis - cat feces
Rubella -

Cytomegalovirus -
Herpes - transplacental transmission (usually in birth canal exposure)usually go for cesarean

others - varicella, parvovirus, syphilis pg 369
exposure to a teratogen in the first trimester will most likely cause? what about in late pregnancy?
first trimester - probably CNS , later hearing impairements and cataracts
Drug ingestations or environmental exposure:
prior to 8 weeks all or none rule results in miscarriage, 8-15 weeks there is a dose response , later exposure has an increased risk for leukemia (timing is important)

radiation can cause cytoenetic breakage
drug ingestations:
first trimester exposure - more than 2oz a day = fetal alcohol syndrome, small head, delay in development and facial appearance
drug ingestation:
and symptoms for each,
what do you do to reduce risk?
ie dilantin
cleft lip small size fingernail hypoplasia, developmental delay

valproic acid -neural tube defects if exposure n first trimester

reduce risk - folic acid summplements 2-3 mo before pregnancy
Maternal Diabetes
type I - insulin dependent
fetuses have hyperglycemia in first trimester, results in malformations

Gestational diabetes - glucose levels in third trimester cause macrosomia(lrg size)
Maternal systemic lupus and Phenylketonuria
lupus -increased miscarriage risk

PKU - dose relationship with microcephaly and congenital heart disease
so many suits it was taken off the market, but never formally proved to be a teratogen,
birth and after
preconception - none
pre-implant - some protection
predifferentiation - "all or nothing effect"
organogenesis - most affected here
postorganogenesis - some agents can cause effects thruout preg
birth - not teragotenic effect
What would the dose response curve be affected by?
metabolite clearance
enzymes for degradation
alcohol and cigarettes
Genetic susceptibility depends on?
fetal modifier genes, how conceptus interacts with environmental factors,
maternal rate of absoprtion, animal studies reduce human risk
congenital malformation, isolation vs several
isolation - look for other malformations

pattern of anomolies - could be a synd/assoc, numbers might change
start off intrinsically abnormal
destructive, process starts off normally and then destroyed
ie amniotic band sequence
TERATOLOGY, structure of tissue was normal, intro of teratogen
blood clot causing disruption of normal development
things were working well and prevented it from developing normally, structure still there, just different, ie oligohydramnios, uterus presses on foot and foot grows abnormally
started off abnormally in terms of single tissue and the tissue develops abnormally

achondroplasia - abnormal bone growth
etiolog (urethral obstruction, etc ) --> oligohydramnios --> phenotype (pulmonary hypoplasia, failed lung development)

seq. - pathogenic feature that leads to a phenotype, BUT the etiology can be diff, is can be from urethral obstruction or chronic leakage or polycystic kidney disease, all these lead to the sequence of oligohydramnios
developmental fields
a developmental field would be ex) pharyngeal pouch (becomes parathyroid, facial structures, etc)

george syndrome
know underlying problem and see patterns
genetic counseling, know when to do it and underlying ideas