Prion Diseases- Exam IV Flashcards
Rare, fatal, rapidly progressing neurodegenerative diseases that occur in humans and other animal species:
prion diseases
In prion diseases, a presence of ___ within the neuropil, results in production of a ___ appearance
small vacuoles; spongiform
The complex net of axonal, dendritic, and glial branchings that form the bulk of the central nervous system grey matter of the brain and in which the nerve cell bodies are embedded:
Neuropil
Describe prion diseases:
rare, fatal, rapidly progressive neurodegenerative diseases that occur in humans and other animal species
What animal prion diseases effect cattle?
bovine spongiform encephalopathy
What animal prion disease effects sheep and goats?
scrapie
Human prion diseases include: (5)
- Kuru
- Creutzfeldt-Jakob disease (CJD)
- Variant Creutzfeldt-Jakob disease (VCJD)
- Gerstmann-Straussler-Sheinker syndrome (GSS)
- Fatal familial insomnia (FFI)
Fatal neurodegenerative disease of sheep:
scrapie
Scrapie is demonstrated to be a ___ disorder
transmissible
Fatal neurodegenerative disease of humans recognized since the 1920s, demonstrated to be transmissible in the 1960s (humans to chimpanzees)
Creutzfeld-Jakob disease (CJD)
What are the early symptoms of CJD?
- memory problems
- behavioral changes
- poor coordination
- visual disturbances
What are the later symptoms of CJD?
- dementia
- involuntary movements
- blindness
- weakness
- coma
What is the outcome of CJD?
70% of people die within 1 year of diagnosis
It was discovered during the search for the infectious agents of CJD and scrapie, that infectious agents were ____ meaning they were not ___, therefore possible a ___.
filterable; not cellular, virus
When determining what the infectious material of scrapie and CJD was, ionizing radiation did not effect transmission, what did this mean?
The infectious material did not contain DNA or RNA
Since ionizing radiation did not affect the transmission of scrapie and CJD, the hypothesis of 1960s concluded that scrapie and CJD are caused by:
solely proteins
What term was created to describe scrapie and CJD:
Prion
The term prion means:
Proteinaceous infection
The cellular protein involved in prions:
PrP (prion protein)
Describe endogenous Prp:
normal disease in body that is not a disease agent
Endogenous Prp can adopts a couple of different conformations:
- normal
- disease-forming
The difference between a normal Prp and a disease-causing Prp occurs at the ____ level
conformational
What is significant about an endogenous Prp converting to prion form?
It can cause other endogenous Prps to convert to the disease causing form
What is responsible for encoding Prp protein?
PRNP gene on chromosome 20
The PrP gene displays:
polymorphism
What do we mean when we say the PrP gene displays polymorphism?
Variance of gene sequence which results in variance of amino acid sequence
Describe one area in the PrP sequence where may see polymorphism:
Met or Val at codon 129 of PRNP gene
What is the occurrence of seeing Met of Val at codon 129 of PrNP gene:
Met 60%
Val 40%
When an invidivual is homozygous for either Met of Val at codon 129 of the PRNP gene, what does this mean?
they are at increased risk of disease (CJD)
The scrapie/prion form of PrP (PrPSc) is resistant to ___ and accumulates in ___.
degradation; amyloid fibrils
PrPC (normal form of PrP) is strongly expressed in both ___ & ___ of the CNS
neurons and glial cells
What is the function of PrPC in the CNS?
regulates ion channels and neurotransmitter receptors at the pre- and postsynaptic levels
What is the median age at death with an individual with CJD?
68 years
What is the median age of death for an individual with variant CJD?
28 years
What is the median duration of illness for an individual with CJD?
4-5 months
What is the median duration of illness for an individual with variant CJD?
13-14 months
What clinical signs and symptoms of CJD?
dementia; early neurologic signs
What are the clinical signs and symptoms for variant CJD?
Prominent psychiatric/behavioral symptoms, painful dysthesias; delayed neurologic signs
Describe the accumulation of PrPSC in brain tissue in an individual with CJD compared to an individual with variant CJD:
CJD: variable accumulation
variant CJD: marked accumulation
What is clinical concern for prion disease?
prions may NOT be inactivated by means of routine surgical instrument sterilization procedures
The WHO and US CDC and Prevention recommend that instrumentation used in prion cases be:
immediately destroyed
Secondary to destruction instruments used in prion cases, it is recommended that ___ and ___ be used in combination to process instruments that come into contact with high-infectivity tissues
heat and chemical decontamination
Since the adoption of current sterilization procedures regarding prion disease instrumentation use in 1976, what have we seen?
no cases of iatrogenic transmission CJD that have been reported
