Ischameia Reperfusion

Question 1

What is preconditions?

Answer 1

One or more brief periods of ischameia –> temporary protection against subsequent ischaemic injury,

Question 2

What mechanisms are thought to allow preconditioning to protect?

Answer 2

Adenosine release (substrate for FR formation)
NO (beneficial signalling)
Prostaglandin induction of HSP
ROS (small amounts induce antioxidants).

Question 3

What are the sources of free radical production in repercussion?

Answer 3

Xanthine Oxidase
Mitochondrial Leakage
Infiltrating neutrophils
Neutrophil Activations

Question 4

What evidence implicates a role for xanthine oxidase?

Answer 4

Allopurinol (XO inhibitor) - protects against a range of ischameia related pathologies.

Question 5

What are the sources of transition metals in IR?

Answer 5

Cell tissue injury
Acidoses –> Tf releases iron stores.
H2O2 attacks Mb –> iron release.
Erythrocyte damage during bypass (Hb release some).