Chapter 56- Prions Flashcards
(24 cards)
Prion diseases are _____ that occur in____
rare,fatal, rapidly progressive neurodegenerative diseases; humans and other animal species
what is a neuropil
complex net of axonal, dendritic and glial branchings that forms the bulk of the CNS gray matter of the brain and in which the nerve cell bodies are embedded
what animal is affected by bovine spongiform encephalopathy
cattle
what animal is affected by scrapie
sheep and goats
what are the human prion diseases
- kuru
- creutzfeldt- Jakob disease (CJD)
- variant creutzfedlt- Jakob disease (variant CJD)
- Gertsmann- Straussler- Scheinker syndrom (GSS)
- fatal familial insomnia (FFI)
what is scrapie
- fatal neurodegenerative disease of sheep
- transmissible disorder
what is CJD
- fatal neurodegenerative disease of humans known since 1920’s
- proven to be transmissible in 1960s
what are the early symptoms of CJD
- memory problems
- behavioral changes
- poor coordination
- visual distrubances
what are the late symptoms of CJD
- dementia
- involuntary movements,
- blindness
-weakness
-coma
what percentage of people with CJD die within 1 year of diagnosis
70%
infectious agents of scrapie and CJD were _____ meaning ____
filterable; not cellular
what does the term prion mean
proteinaceous, infectious agent
describe how the prion shape is formed
PrPsc recruits PrP
what is the non prion from called
PrP or PrPc
PRNP gene on chromosome 20 encodes ____
PrP protein
describe PrP polymorphism
- Met or Val at codon 129 of PRNP gene
- 60% methionine codon
- 40% Valanine codon
- homozygote for either = increased risk of disease
what is PrPSc resistant to and where does is accumulate
- degradation
- amyloid fibrils
where is PrPC strongly expressed and what does it do
- in both neurons and glial cells of the CNS
- regulates ion channels and NT receptors at the pre and postsynaptic levels
what is the median age of death with CJD and variant CJD
- CJD: 68 years
- variant CJD: 28 years
what is the median duration of illness
- CJD: 4-5 months
- variant CJD: 13-14 months
what are the clinical signs and symptoms of CJD and variant CJD
- CJD: dementia, early neurologic signs
- variant CJD: prominent, psychiatric/behavioral symptoms; painful dysthesias, delayed neurologic signs
what is the amount of accumulation of PrPSC in brain tissue
-CJD: variable accumulation
- variable CJD: marked accumulation
Prions may not be inactivated by means of _____
routine surgical instrument sterilization procedures
the world health organization and the Us centers for disease control and prevention recoemmend that instrumentation used in such cases be _____
immediately destroyed after use
- heat and chemical decontamination be used in combination to process instruments that come in contact with high infectivity tissues
