Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > M19 - Prions (sterilisation) > Flashcards

M19 - Prions (sterilisation) Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Name prion based diseases.

A
  • Scrapie (BSE of cattle)
  • Creutzfeldt- Jakob disease
    (sporadic / inherited)
  • Gerstmann- straussler- Schenker
    -Kuru
    -New variant CJD
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the most common type of Creutzfeldt- Jacob disease (CJD)

A

Sporadic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

who is most effective by sporadic CJD?

A

patient over 60 years old (elderly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what happens in sporadic CJD?

A

rapid dementia to death (4.5 months)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

where are the highest levels of prions in sporadic CJD?

A

in CNS , also retina and sensory ganglia, but not in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the other type of CJD which effects younger patient in their 30s?

A

Variant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is variant CJD?

A

fatal Human neurodegenerative condition classified as transmissible spongiform encephalopathy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the risk of variant CJD?

A

Risk of person to person spread by contaminated surgical- instruments that have not been cleaned, disinfected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what prion protein is found in vCJD?

A

PrPsc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is important in CJD?

A

PRNP codon 129 of Prion Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what Amino acids are found are position 129?

A

methionine or valine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the different genotypes of vCJD

A
  • Homozygous MM
  • Homozygous VV
  • Heterozygous MV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the genotype of 177 of 178 cases of vCJD?

A

MM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what gene appears significant in CJD?

A

PrP gene

-amino acid variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the symptoms of vCJD?

A

-Average age 28 (65) -progressive dementia, sensory symptoms, unsteadiness,
involuntary movements, immobile & mute
death <14 mths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens in the brain in vCJD?

A
  • Brain vacuolation, neural apoptosis
  • Accumulate misfolded protease- resistant prion protein
  • Protease Resistant Prion protein PrPSc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is vCJD linked to?

A

BSE

18
Q

what is BSE?

A

infectious agent for scrapie resistant to treatments that destroy DNA

19
Q

what is a prion?

A
  • Proteinaceous infectious particle

- a protein that can replicate itself within the body

20
Q

Critically what are the 2 forms?

A

PrP^C , PrP ^Sc

21
Q

what is PrP^C converted to?

A

PrP^Sc

22
Q

what is PrP^Sc resistant to?

A

protease

23
Q

what does prions accumulate as?

A

Plaques

24
Q

what does newly converted PrP^Sc convert?

A

more PrP^C

25
Q

Describe PrP^C.

A
  • made normally by body
  • preferentially produced in neurons
  • functions in stability of myelin sheath and memory
  • chemically identical to PrP^Sc
26
Q

what is the amount of PrP^Sc proportional to?

A

infectivity

27
Q

what reduces infectivity of prions?

A
  • agents that destroy protein function

- antibodies to PrP^Sc

28
Q

what is the difference between prion and virus?

A 
Prion -NO Virus - YES
•  Immune response
•  Disinfection by
–  Formaldehyde
–  Proteases
–  Heat (80 ̊ C)
–  Ionizing &amp; UV radiati
29
Q

Describe the life cycle of prion in the body.

A
  • Uptake via Peyers Patches (intestine)
  • Circulates in blood
  • Accumulates (replicates?) in Lymphoid Tissue
  • Enters nerve or crosses blood/brain barrier
  • Accumulates in brain
30
Q

Describe the peripheral distribution of vCJD.

A

• Lymphoid tissue
– Tonsil,lymph node, spleen (unique to vCJD)
– Not salivary gland tissue
• Neural Tissue
– Trigeminal ganglion but not cranial nerve
• Blood
– 4 confirmed transfusion cases

31
Q

Assaying infective risk.

A
  • Use & reuse of surgical instruments
  • Standard ‘decontamination’ reduces risk
  • Risk (of contamination)
32
Q

what does the risk of contamination depend on?

A
  • number of infected people
  • length of incubation period
  • levels present in tissues
  • infective dose
33
Q

when can contamination and transmission occur?

A
  • surgery (CNS, eye, lymphoid tissue)
  • Dentistry
  • Inwards routes for transmission (tonsils , gums, tongue, dental pulp)
34
Q

Describe decontamination.

A 
•  Cleaning
–  removing mass of material 
•  Autoclaving
–  partially deactivates material
•  Files&amp;ReamersProblem;
–  difficulty removing material
–  Average 8-10 patients before discarded
–  USA single use
–  Contamination with dental pulp (?)
35
Q

How is there a new emphasis on removing prion material?

A
  • Washer-disinfectors automate process
  • Robust cleaning
  • Reduced exposure to sharp implements
36
Q

What decontamination is involved in vCJD patient?

A

dispose of instruments & avoid retraction of oral fluids

37
Q

What decontamination is involved in general patients?

A

autoclaving at 134 ̊C & immersion in 1M NaOH, or 1M NaOCl

38
Q

When assessing the risk of transmission by new infectious agent, what is unlikely?

A

• Damage epithelial of infected patient (tonsil).
Human dental pulp not yet shown to contain prions
• Survive cleaning/autoclaving.
• Come into contact with receptive surface on next patient.

39
Q

When assessing the risk of transmission by new infectious agent, what is likely?

A

• Limits to detection, scale of problem unknown
sub-clinical carriers
• Ability to survive autoclaving/ cleaning
files/reamers difficult to remove dental pulp
• Infective dose unknown
Large amount of endodontic surgery

40
Q

What are some prion research involving field?

A
  • model for neurodegenerative disorders
  • improved testing
  • treatments possible (drugs)

Microbiology (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions