Teratogens2 1 (1)

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Prescription Drugs

Transcript of Teratogens2 1 (1)

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Prescription Drugs

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Prescription Drugs

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Higher order question: What factors influence how severely teratogens influence the developing organism? Most vulnerable in the early stages of pregnancy More frequent exposure and higher doses =

more severe damage Poor nutrition, lack of prenatal care, and

presence of multiple teratogens can worsen effects

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Effect depends on organism: Thalidomide: human fetus extremely sensitive; no effect on

rats or rabbits

Importance of timing of exposure: During the zygote period: Fluids do not mix with mother’s,

not as susceptible. Embryonic period: Organs are forming and are especially

vulnerable. Fetal period: Growth retardation and tissue damage.

Rubella in mothers affect 2-3% in the zygote period; 50% in the early embryo period (1st month); 22% in the late embryo period (2nd month); 6-8% in the early fetal period (3rd month).

What factors influence how severely teratogens influence the developing organism?

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What common teratogens haven’t been discussed?

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Alcohol: F e t a l A lc o h o l S y n d r o m e ( F A S ) : A

cluster of abnormalities that appear in the offspring of mothers who drink alcohol heavily during pregnancy

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Fetal Alcohol Syndrome

Facial abnormalities Heart problems Lower IQ

Developmental lag Poor attention Poor social skills

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Study on effects of moderate drinking (Streissguth, 1989)

Low versus moderate consumption of alcohol Less than 1.5 oz (1/4 glass) alcohol/day More than 1.5 o z alcohol/ day

Design features: Large sample (n= 421) Longitudinal (prenatal to 4 yrs old) Control for: education race, smoking, aspirin,

antibiotics, illicit drugs, sex & birth order, preschool attendance

Findings: Moderate consumption lowers IQ by 4

points 3 times greater risk for IQ lower than 85

by age 4 Poor heart and lung function at birth

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Alcohol interferes with migration of neurons during brain development

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Amount of alcohol ingested does not uniquely determine severity of FAS

Susceptibility is affected by the mother’s physiological state: Age Nutritional status Overall health, etc.

Effects of agents on the mother might be negligible or temporary

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Street Drugs

M a r i ju a n a : Growth retardation Premature birth Poorer verbal and memory development at 4 years of age

C o c a in e a n d C r a c k : Growth retardation Spontaneous abortion Premature birth Withdrawal symptoms such as tremors and irritability

H e r o in a n d m e t h a d o n e : Deficient growth SIDS Withdrawal symptoms Premature birth

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Study on cocaine and tobacco useNess et al., 1999

A large inner city sample n = 400, miscarriages n = 570, no miscarriage Adjusted for demographics and other drug use

Findings: S e l f -r e p o r t e d c o c a in e u s e : neither

drug was significantly related to miscarriage A c t u a l u s e w a s d e t e r m in e d b y

a n a ly s is o f u r in e a n d h a ir s a m p le s : both drugs were significantly related to miscarriage Cocaine increased probability of miscarriage 1.4

times Smoking increases probability of miscarriage 1.8

times

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Cocaine “crack” babies of the 1990s

Child born to mother who used crack-cocaine during pregnancy

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Once written off as “lost generation” Susceptible to prenatal stroke,

irreversible brain damage, or a heart attack

Withdrawal symptoms at birth Increased risk of mental

retardation and cerebral palsy Deficits in information-

processing, and attention to tasks

The Parent Child Intervention Program was established specifically to help prenatally drug-exposed youngsters. Teachers try to provide a carefully monitored and highly structured environment for the students.

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Crack babies are now seen as 1990s myth because adopted babies do well

It was the post-natal environment, combined with prenatal vulnerability, that led to learning disabilities and ADHD in cocaine-exposed children

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Addendum: Theorists working in new or unexplored domains often borrow ideas from well understood domains

E x a mp l e : T h e s o la r s y s t e m m a y h a v e s e r v e d a s t h e s o u r c e

D o m a in f o r N e i l B o h r ' s m o d e l o f t h e a t o m .

S o u r c e d o m a in : S o la r s y s t e m ' s p la n e t s a r e k e p t c ir c l in g a r o u n d t h e s u n b y g r a v it a t io n a l f o r c e s

T a r g e t d o m a in : e le c t r o n s c i r c le t h e m a s s f o r m e d b y p r o t o n s a n d n e u t r o n s

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Characteristics of the Stages of Organogenesis

N o t u r n in g b a c k : T im e ( v ia a m a t u r a t io n a l

c lo c k ) d r iv e s t h e s t a g e s O r g a n s c a n o n ly

d i f f e r e n t ia t e d u r in g a c e r t a in p e r io d

N o s e c o n d c h a n c e s D e v e lo p m e n t p r o c e e d s v ia : In c r e a s in g d i f f e r e n t ia t io n

o f s t r u c t u r e s In c r e a s in g in t e g r a t io n o f

s t r u c t u r e s

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Prenatal development: “No turningback…

F r e u d b o r r o w e d " n o t u r n in g b a c k , n o s e c o n d c h a n c e s " f r o m s t u d ie s o f m a m m a l ia n p r e n a t a l d e v e lo p m e n t w h e n h e f o r m u la t e d h is t h e o r y o f h u m a n p e r s o n a l i t y d e v e lo p m e n t .