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24 Cards in this Set
- Front
- Back
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How do cows get Bovine encephalopathy?
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Sheep are infected with scrapie --> then the sheep are fed to the cows , and the cows are then fed to humans
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Chronic Wasting Disease is a disease found in ___________.
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Deer
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What are the 2 ways that humans get infected with prions?
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1. Acquired infections
2. Mendelian transmission of a DOMINANT/autosomal gene. They are BOTH INFECTIOUS and INHERITED!!! (Or they can be sporadic) |
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How are prions absorbed when they are acquired by food?
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Taken in & absorbed in the GI tract at the PEYER's patches (mucosal lymphoid tissue) --> lymphoid cells phagocytose the particle and travel to other lymphoid sites such as the nodes/lymph/ and spleen --> they will replicate here --> if there is a nearby nerve, it will be taken up and moves back up the axon to the spinal cord and eventually the brain.
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Scrapie is a disease of ________?
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Sheep
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What are the 3 diseases that are slow viruses in animals?
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Scrapie --> Sheep
Bovine encephalopathy --> cows Chronic Wasting disease --> deer |
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What are human diseases caused by prions? What is their mechanism of transmission?
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Kuru --> A form of CJD that was transmitted to others during ritualistic eating of brains of dead relatives or through infection via the cutting of the skin during the slaughter of the body.
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What is the characteristic histological feature of encephalopathies?
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Vacuolization of brain tissue + spike balls found in the cerebellum
Alzheimers Disease: preogressive dementia due to amyloid plagues and NF tangles which are deposits of amyloid protein and tangles are intracellular accumulations of the cytoskeletal protein tau. |
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What are the two histological features seen in a brain of an Alzheimers pt?
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NF tangles & amyloid plaques
NF: cytoskeletal protein taue amyloid plagues: deposits of amyloid proteins |
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What areas of the brain are affected by AD?
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amygdala + hippocampus + surrounding areas
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What is the pathology of AD?
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There is a impairment of the catecholaminergic, seratonergic, and cholinergic transmission --> causing erosion of judgement, reasoning, verbal fluency, and cognition.
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___________ is an "industrialized" form of Kuru?
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CJD
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What is the clinical picture of a CJD patient?
Describe the gross & microscopic appearance of the brain? |
Dementia, paralysis, death
cortical atrophy/widening of sulci/gliosis; microscopically the brain appears vaculated as well. |
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What region of the brain is affected by CJD?
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The cerebral cortex
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Fatal familial insomnia affects what region of the brain?
GSS affects what region of the brain? What is the result of this damage? |
selective atrophy of the brain
cerebellar ataxia and as a result motor problems --> dementia less common |
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What are the characteristics of prions?
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animal-to-animal transmission
resistant to nucleases resistant to boiling/ UV/ radiation Lack antigenicity/immunogenicity produce encephalopathy (NOT encephalitis) |
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What is the mechanism of action of the prion?
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Causes a change in conformation of a normal cellular protein (PrP) to a diseased protein (PRPSc) --> the protein builds up in the brain and forms clumps that damage and destroy nerve cells which forms sponge-like holes in the brain and leads to mental and behavioral features of prion diseases.
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What is the difference between conventional and unconventional slow viruses?
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Conventional --> caused by typical viruses
Unconventional --> caused by nonconventional viruses: viroids/virusoid/satellite virus/prions |
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What is remarkable about prions?
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They are self-replicating and they DO NOT contain nucleic acids as do other infectious particles
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How do prions infect other normal proteins?
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When they enter into a cell, they cause the folding of a normal protein into a diseased protein and use the diseased protein as a template to make more
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What are some examples of conventional slow viruses?
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SSPE --> defective form of MEASLES
PML --> polyoma virus (BK, JC) Progressive Congenital Rubella Herpes simplex virus: acute encephalitis Rabies: Negri bodies HTLV-3 --> causes AIDS with incubation of 5-10 years. |
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After which virus do you contract SSPE? What does it cause?
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MEASLES!
Motor and mental degeneration; spasms |
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PML is associated with which class of viruses?
What happens in this disease? |
Polyoma (immunocompromised pts.)
In PML there is demyelination of the oligodendrocytes --> memory loss and loss of coordination --> typically seen in AIDS patients |
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What is the histological feauture of Rabies?
What feature of rabies makes it a slow virus? |
Negri bodies
It has a long incubation period |
