Chapter 56- Prions

Question 1

Prion diseases are _____ that occur in____

Answer 1

rare,fatal, rapidly progressive neurodegenerative diseases; humans and other animal species

Question 2

what is a neuropil

Answer 2

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

Question 3

what animal is affected by bovine spongiform encephalopathy

Answer 3

cattle

Question 4

what animal is affected by scrapie

Answer 4

sheep and goats

Question 5

what are the human prion diseases

Answer 5

• kuru
• creutzfeldt- Jakob disease (CJD)
• variant creutzfedlt- Jakob disease (variant CJD)
• Gertsmann- Straussler- Scheinker syndrom (GSS)
• fatal familial insomnia (FFI)

Question 6

what is scrapie

Answer 6

• fatal neurodegenerative disease of sheep
• transmissible disorder

Question 7

what is CJD

Answer 7

• fatal neurodegenerative disease of humans known since 1920’s
• proven to be transmissible in 1960s

Question 8

what are the early symptoms of CJD

Answer 8

• memory problems
• behavioral changes
• poor coordination
• visual distrubances

Question 9

what are the late symptoms of CJD

Answer 9

• dementia
• involuntary movements,
• blindness
  -weakness
  -coma

Question 10

what percentage of people with CJD die within 1 year of diagnosis

Answer 10

70%

Question 11

infectious agents of scrapie and CJD were _____ meaning ____

Answer 11

filterable; not cellular

Question 12

what does the term prion mean

Answer 12

proteinaceous, infectious agent

Question 13

describe how the prion shape is formed

Answer 13

PrPsc recruits PrP

Question 14

what is the non prion from called

Answer 14

PrP or PrPc

Question 15

PRNP gene on chromosome 20 encodes ____

Answer 15

PrP protein

Question 16

describe PrP polymorphism

Answer 16

• Met or Val at codon 129 of PRNP gene
• 60% methionine codon
• 40% Valanine codon
• homozygote for either = increased risk of disease

Question 17

what is PrPSc resistant to and where does is accumulate

Answer 17

• degradation
• amyloid fibrils

Question 18

where is PrPC strongly expressed and what does it do

Answer 18

• in both neurons and glial cells of the CNS
• regulates ion channels and NT receptors at the pre and postsynaptic levels

Question 19

what is the median age of death with CJD and variant CJD

Answer 19

• CJD: 68 years
• variant CJD: 28 years

Question 20

what is the median duration of illness

Answer 20

• CJD: 4-5 months
• variant CJD: 13-14 months

Question 21

what are the clinical signs and symptoms of CJD and variant CJD

Answer 21

• CJD: dementia, early neurologic signs
• variant CJD: prominent, psychiatric/behavioral symptoms; painful dysthesias, delayed neurologic signs

Question 22

what is the amount of accumulation of PrPSC in brain tissue

Answer 22

-CJD: variable accumulation
- variable CJD: marked accumulation

Question 23

Prions may not be inactivated by means of _____

Answer 23

routine surgical instrument sterilization procedures

Question 24

the world health organization and the Us centers for disease control and prevention recoemmend that instrumentation used in such cases be _____

Answer 24

immediately destroyed after use
- heat and chemical decontamination be used in combination to process instruments that come in contact with high infectivity tissues