2.1 Acute inflammation part 3 Flashcards
What are the two means of destroying phagocytosed material?
Oxygen dependent and independent
What is the enzyme that converts Oxygen to superoxide?
NADPH oxidase
What is the enzyme that converts superoxide to H2O2?
Superoxide dismutase
What is the enzyme that converts H2O2 to HOCl?
myeloperoxidase
What is the most effective mechanism to kill phagocytosed material? What is involved with this?
- O2 dependent killing
- HOCl generated by the oxidative burst destroys phagocytosed microbes
What is the defect in chronic granulomatous disease? Inheritance pattern?
-XLR or AR deficiency in NADPH oxidase, causing a loss of oxygen dependent killing
What are the organisms that are catalase positive?
Cats Need PLACESS
Nocardia Pseudomonas Listeria Aspergillus Candida E. Coli Staph Serratia
What are the obligate aerobes?
Nagging Pests Must Breathe
- Nocardia
- Pseudomonas cepacia
- Mycobacterium TB
- Bordetella
Why is it that pts with chronic granulomatous disease do not have trouble killing catalase negative bacteria?
H2O2 produced by bacteria can be converted to HOCl. (NADPH is sooner in the pathway)
What is the function of catalase?
H2O2 to H2O
What is the nitroblue tetrazolium test involved in diagnosing chronic granulomatous disease?
Turns blue if NADPH oxidase can convert O2 to O2-
remains colorless if not
What is the usual presentation of MPO deficiency?
- Asymptomatic but increased risk for candida infections
- NBT test normal
What is the defect in MPO deficiency? What are they at increased risk of developing? Result of the NBT test?
- Defective conversion of H2O2 to HOCl
- Increased risk for candidal infx
- NBT test is normal
What is the MOA of O2 independent killing?
occurs via enzymes present in leukocyte secondary granules (lysozyme and MBP)
What happens to the PMNs when the infection has resolved?
Undergo apoptosis within 24 hours of resolution
