Tetatogenic inheritance Flashcards
what is tetraogenesis
-abnormal development influenced by drugs, viruses, chemicals, radiation, inutero
-therefore a mammalian phenomenon
-environmental influenced during gestation
examples of tetraogenesis
-twisted leg (cattle)
-cyclopia (lambs)
-cleft pallet (cattle, dogs)
-heart defects (sheep)
what is the biological threshold
-developmental processes that occur on a fixed schedule
-at a fixed period in gestation, disruptions or delays cause that organ to be incompletely developed
neural tube closure in humans
-start with your neural plate flat open and you anterotary and postouitary side
-neural groove somites (folding)
-then develop neural fold (starts to zip/close)
-completely closes and turns into neural tube
what happens if ends dont close in neural tube closure
spina bifida
what is spina bifida
-neural tube doesnt close by day 25 in gestation
-more common in cockasians and hispanic
-but environmental factors play a big role
causes spinal bifida risks
-maternal folic acid deficiency
-exposure to high temperatures in early pregnancy (pronged fever or hot tub use)
-maternal insulin dependent diabetes
-medications (anti seizure)
cleft lip and palate
-in utero development of face at 7-9wks (cattle)
-fixed time period of facial development
-delay (fever, virus)
-face not finished
-failed fusion of nasal process
-more common in bulldog breeds (genetic component?)
-maybe multifactorial but also congenital so not sure where to classify
-more common when more then one child effected
-drugs due to illness
-smoking
teratogenesis factors
-genetic background:
-predisposition to the teratogen
-predisposition to the malformation
-exposure:
-time & length
-dose
teratogenesis generlizations
-animal pregnant or lactating at time of exposure (rarely through male)
-few effects last from prior conception
-most effects have a two week delay
-“preimplantation” a “safe” period or embryo dies
-primarly congenital defects
developmental stage at time of exposure
blastocyst-lethality
organogenesis-structural defect
histogenesis-microscopic changes
growth-stunting
access of the teratogenic agent
-direct:
-radiation
-microwave
-ultrasound
-indirect
-maternal blood via the placenta (alters absorption and doses)
physical teratogens
-temperature:
-fever, overheating, hypothermia
-ultrasound:
-high frequency sound wave used to direct preg test but has possibility of thermal damage
-electromagnetic field:
-power towers
-appears more bone abnormalities but not 100% confirmed or denied
biological teratognes
-malnutrition
-viruses
-disease
-twinning
different types of malnutrition teratogens
-malnutritioin
-specific dietary deficiencies
-specific foods
malnutrition teratogen
-generally low birth weigh
specific dietary deficiencies
twisted legs (arthogruposis)
due to manganese deficencies
specific teratogen foods
-locoweed
-lupine
-veratrum spp
-sudan grass
-tobacco stocks
lupine
-grows in cypresshills region
-crooked calf disease
-high conc of alkaloids
locoweed
abortions+malformations in sheep and cattle
vetatrum spp
-grows in foot hills
-cyclopia in lambs if ewes ingest about day 14 of gestation
-poison of the rizomes on plant
sudan grass
-arthrogryposis in horses
-also cows but not as severe
-not native to NA
tobacco stocks
-byproduct of the cig industry
-when fed to pigs piglets developed stiff and swollen joints
-and a lot of stillborn
tetarogen=nicotine
biological teratogen: viruses (bovine viral diarrhea)
-abortion
-CNS damage
-persistent in infected calves
-weak small
biological teratogen: disease-diabeates
-diabetes in dogs
-spikes and dips in glucose prob the teratogen
-babies born from diabetics= higher congenital defects (spinabifida)
biological teratogen: twinning mortality
-twin mortality:
-horses (draft twin more easy)
-90% abort
-~50% of live births survive
-cattle: 30-40% abort
biological teratogen twin morbidity
-premature birth typical
-low birth weigh (~75% of average)
-respiratory problems (under developed lungs)
-positioning effects
-limb deformities
-freemartinism
chemical teratogens
-food additives
-pollutants
-drugs
chemical teratogens: food additives
-ethoxyguin (dog food preservative)
-skin problems
-abortion?
-animal feed additive
-reduction of use- several countries do now allow use
chemical teratogens: pollutants
sour gas
-increased sulfur because plants take it up which decreases selenium
-white muscle disease in calves
chemical teratogens: drugs (wormers)
-albendazole
-anury- agenesis of the tail, anus, CNS in cattle & sheep
-rumental ok in lactation sheep and animals
-ivermectin found to be ok during gestation
chemical teratogens: drugs (antibiotics)
-chloramphenicol
-can not be used in food producing animals
-aplastic anemia in humans (bone marrow damage form milk)
-would this occur in pups?
-regulations are made to protect humans not animals
chemical teratogens: drugs (medications)
-prescribes for seizures
-can cause a broad spectrum of major defects (5/77 human pregnancies)
-and mildly depressed congenital and language abillities
-but… frequent seizures can cause hypoxia and fetal distress and/or defects
