Prions and Prion-Mediated diseases Flashcards Preview

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Flashcards in Prions and Prion-Mediated diseases Deck (27)
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1

What lead to CJD iatrogenic transmission?

Transmission of CDJ occurred despite sterilization of instrumentation used on pts

2

What is the only way to destroy and prion?

Incinerate them

3

Where would the prion protein (PRNP) be found?

Naturally occurring CNS protein encoded by the PRNP gene

4

What are some characteristics of the prion protein?

Non-pathogenic
Single disulfide bond
N-glycosylated
Attatched to plasma membrane by a C terminal
PrPc largely alpha helical
Structured and unstructured region

5

What occurs based on the Protein only hypothesis by Prusiner?

Only protein contributes to this spongiform encephalopathy
Protein misfolds and becomes PrPsc (scrapie) and accumulates plaques in brain

6

As they start to stack up what does PrPsc form?

Fibrils

7

What are the characteristics of PrPres?

Abnormal, partially protease resistant, prion disease associated isoform of PrP
Largely synonymous with PrPsc

8

What occurs in the autocatalytic model what seeded PrP polymerization occurs?

Confirmational converstion of PrPc to PrPres is rare unless cataluzed by contact with a pre-existing PrPres multimer

9

What occurs in the noncatalytic model?

Confirmational interchange between PrPc and PrPres conformations is rapid but PrPres conformer is poorly populated unless stabilized

10

What does PrPc do normally?

Not really known but expected to act in signal transduction primarily in neurites

11

What protein is similar to PrPc?

Doppel

12

What is amino acid 106-126?

Neurotoxic prion protein fragment

13

What are prions?

Proreinaceous infectious particles

14

How can abnormal prions occurs?

From animal to animal
Spontaneous mutation

15

What does the pathological form of prion do?

Binds to normal isoform, causes normal changes to abnormal confirmation

16

What is the main difference between normal and abnormal PrP?

Normal: Helical, degradation by proteases
Abnormal: Beta-pleated protein, resistant to degredation by proteases

17

In transmissible spongiform encephalopathies, what does the brain show?

Scrapie-associated fibrils
Vacuolization and atrocytosis

18

What are the types of spongiform encephalopathies that effect humans?

CJD
Variant CJD
Gerstmann-Straussler syndrome
Fatal familial insomnia
Kuru

19

How is Kuru transmitted?

Eating the brain tissue of deceased family members or open sores

20

What gets scrapie?

Sheep

21

What are the characteristics of scrapie?

Neurodegenerative disease
Caused by contact with placenta and placental fluids in infected ewes

22

What are the three route of acquisition of Creutzfeldt-Jacob disease (CJD)?

Sporadic
Familial
Iatrogenic (transplanted corneas, incorrect brain electrode sterilization, pituitary growth hormone injection from cadavers)

23

What are the clinical manifestation of CJD?

Insidious onset of psychomotor disturbances
Progressive memory loss
Dec cognition
Myoclonus
Death within months from symptom onset

24

Where does variant CJD come from?

Cows

25

How do someone acquire vCJD?

Eating infected meat from cattle infected with BSE

26

What id different in vCJD from CJD?

Different prion protein
Younger age onset
Sensory disturbances, psychiatric issues
Different electrical patterns

27

What is the proposed pathogenesis of vCJD?

Orally ingested prions absorbed and transported to blood and lymph fluid
Peripheral replication in the spleen, tonsils or other lymph tissue
Prions transported to brain by peripheral nerves
Cross BBB