Prions Flashcards
t/f are prions viruses?
FALSE
types of prions
- transmissible spongiform encephalopathies
- bovine spongiform encephalopathy
- scrapie
- Chronic wasting disease
mad cow disease
bovine spongiform encephalopathy
transmitted by feeding cow meat and bone meal to other cows
strict rules govern animal feed and screening of animals is done
what has scrapie
sheep and goats
chronic eating disease
deer, elk, antelope
transmitted through cuts in the skin
how does human disease from prions come
from eating nervous tissue or the tongue of diseased animals
Creutzfeldt-Jakob disease
in humans rare degenerative invariably fatal brain disorder about 1 per million persons can be sporadic, hereditary or acquired
sporadic Creutzfeldt- jakob disease
at least 85% of the cases
acquired Creutzfeldt- jakob disease
from transplants
<1% of cases
inherited Creutzfeldt- jakob disease
from a mutant proteins
5-10% of cases in the US
vCJD outbreak
in the UK from beef in the 90s and killed 177
eating meat, tongue of diseased animals
Kuru
cannibalism
from eating human brains
papua New Guinea
diagnosis
patients referred due to behavioral changes
must rule out other causes of dementia including treatable encephalitis and meningitis
by protein detection from biopsies or brain sectioning on autopsy
diseases by prions
progressive disease; have vacuolization of the grey matter of the brain
long term- 20 or more years until symptoms
neurological impairment- anxiety, memory loss, mode changes etc
movement problems: muscle twitching, spasms
loss of speech, coma and death
can prions be detected by Antibodies
no
because they do not induce an immune response
prion disease treatment
NONE
Prions are
Single proteins found in the nervous system on the surface on the neurons in the brain
What happens when prions contact normal cellular proteins
They contact and induce a normal cellular protein to change shape and to become a prion protien
Infectious protein hypothesis
When a normal protein converts to the prion form
PrPc= the prion cellular counterpart
PrPres= prions
The prions turn only their own cellular counterpart into prions
They will not, do not affect other proteins
Affected regions of the human brain that are affected by different TSEs
- Cerebrum
- Thalamus
- spinal cord
- cerebellum
Proteins prions proteins are extremely hard to inactivate. Why?
Resistant to:
- Routine autoclaving
- Proteases
- Organic solvents
- Alkaline cleaners
- UV light
- Radiation
- Ethanol
- Formaldehyde
To inactivate need:
1N NaOH or undiluted bleach
And autoclaving at 121C for 1 hour
What is TSE
Transmissible spongiform encephalopathy
