clinical vingettes Flashcards
Please describe the pathophysiology of Alzheimer’s disease.
Lifelong buildup of Amyloid-ß42, leads to plaques; these plaques cause inflammatory responses, neurofibrillary tangles, and widespread neuronal dysfunction and loss.
What role does post translational amyloid precursor protein processing play in the pathogenesis of Alzheimer’s disease?
When the amyloid precursor protein is first cleaved by ß secretase and then by γ secretase and the remaining protein is 42 kilobases (Aß42) a disease state is possible.
What are some interventions that could delay onset or prevent development of Alzheimer’s?
Find a better vaccine that creates safe antibodies to amyloids Optimally find a way to decrease beta secretaseIncrease Aß42 clearance w/statins/other drugsDecrease Aß42 toxicity
What is the relationship between prion proteins and infectious prions at the protein level?
The prion protein is the product of a chromosomal gene. All mamillian brains contain the gene that codes for the prion protein. The infectious prion is simply an alternative form of the prion protein.
How can prion disease be sporadic?
Two normal forms of the prion protein can associate and spontaneously turn into the beta pleated sheet infectious version of the same protein.
How can prion disease be infectious?
One can be exposed to dangerous prions through food or surgery and become infected.
How can prion disease be heritable?
About 10% of cases occur this way. There can be a mutation in the prion protein gene that leads to the formation of the infectious prion protein.
What is the relationship between bovine spongiform encephalitis (BSE) and variant Creutzfeldt Jakob disease (vCJD)?
In Britain, the peak in vCJD occurred about 6-8 years after the peak in BSE in cattle. This is because people were eating the cattle and the prion was taking its sweet time to come into effect as some do. Moo.
What is a prion strain”?”
Some types of prions have distinct characteristic features such as incubation time in defined host, clinical signs, distribution of protease resistant PrP in brain of affected animal. These features are stable on serial propagation. Certain biochemical properties of PrPSc appear to be strain-specific.
Describe the criteria for classifying a hereditary cancer syndrome as Li Fraumeni syndrome.
Threefold:1. Proband with sarcoma diagnosed before 45 years of age, AND2. A first degree relative with any cancer under 45 years of age, AND3. A first or second degree relative with any cancer under 45, or a sarcoma at any age.
What is the Knudson two hit hypothesis?
First, a hit could damage a germline p53 allele and mutate it (tumor suppressor). Then, a second hit to the DNA could damage another gene, like an oncogene, and activate it. Then you get cancer.
What is the function of p53 in response to UV exposure?
p53 protects us from UV light and the damage that it causes to the genome.
