Tutorials 1-3 Flashcards
What is latency?
The ability to induce a lifelong infection in a host cell.
How do viruses differ from normal host cells? (4)
- No functional ribosomes
- No cellular organelles
- Produce very few of the enzymes needed for viral replication
- Can encode genetic information into RNA
What is acyclovir?
A nucleoside analogue, used as a lifelong medication for immunosuppression and reduction of viral load of the HSV virus.
What are the six variants of the Herpes virus?
1) HSV1
2) HSV2
3) Epstein-Barr virus (EBV)
4) Cytomegalovirus (CMV)
5) Human herpes virus 5 (HHV6)
6) Varicella zoster virus (VZV)
What are the three major components of the herpes virus?
1) Herpes simplex virus (HSV)
2) Cytomegalovirus (CMV)
3) Epstein-Barr virus (EBV)
What is selective toxicity?
Ability of a drug to selectively target specific sites relative to the microorganism that is causing the infection without harming host cell. Basis for chemotherapy.
What is a nucleoside?
A base and a sugar bonded together.
What OTC medications is acyclovir incorporated into?
Cold sore medication (and prescriptions to treat Chickenpox)
How does acyclovir stop viral replication of HSV?
- Acyclovir is taken up by cell and phosphorylated a number of times by thymidine kinase (and other cellular enzymes) to produce acyclovir triphosphate.
- Acyclovir triphosphate competitively inhibits viral DNA polymerase.
- If incorporated, acyclovir is missing 3’ end of carbon, meaning elongation is impossible and chain termination occurs.
What are the steps of the viral life cycle?
1) Attachment to cell
2) Penetration of cell by endocytosis
3) Uncoating of viral contents
4) Biosynthesis
5) Assembly of new phage particles
6) Release
Where is creatine kinase at its highest concentrations?
Highly metabolically active tissues such as the muscle and brain.
How can creatine be ingested?
In red meat and fish.
Where is creatine endogenously produced in the body?
Pancreas, liver and kidneys.
What is creatine kinase used for?
Phosphorylation of creatine into creatine phosphate (energy store).
What can CK in the blood indicate?
Cell death as it leaks from cells upon death.
What is an isoenzyme?
Has the same function but different structures.
How many isoforms of CK are present in the body?
3
What are the different isoforms and where are they found?
MM - skeletal muscle tissue (85%)
MB - myocardium (15%)
BB - brain (mainly)
What is a myocardial infarction?
A heart attack caused by a blockage in the coronary arteries, preventing blood flow to the heart and resulting in cell death.
What are the molecular weights of both monomers?
Roughly the same (43kDa)
What are the isoelectric points of both monomers?
B is 5.2 whilst M is 6.7.
How can CK-MB levels show cell damage in the heart?
CK-MB levels in the blood are directly proportional to the amount of cell death in the heart as each myocyte is of equal volume and will release equal volume of CK into the blood upon death.
How can the isoforms of CK be separated?
Gel electrophoresis or column chromatography.
How is cell death caused in MIs?
- ATP is needed to maintain ion gradients in between the outside and inside of cells
- If blood flow is occluded, ATP is not delivered to cells and ion gradients are unregulated
- The unregulated ion gradients can lead the cell membrane to be compromised.
- Lysozyme can then leak out of the cell, causing self-digestion
- CK is then able to also leak out of the cell into the bloodstream where it is detected
