Generation of Reactive Oxygen and Nitrogen - Goueli Flashcards
Why are oxygen radicals and RNOS important?
Produce cellular dysfunction by reacting (extracting electrons from): Lipids Proteins Carbohydrates DNA
What does Nitro Blue-Tetrazolium Test?
Tests the phagocytic function of polymorphonuclear leukocytes (PMNLs)
What is Chronic Granulomatous Disease?
phagocytes (neutrophils, eosinophils, monocytes/macrophages) have genetic defects in NADPH oxidase
What is Chronic Granulomatous Disease characterized by?
Recurrent life-threatening bacterial and fungal infections and granuloma formation
What allows for infections with catalase positive microbes to survives in the phagosome?
Catalase degrades small amount of hydrogen peroxidase produced by infecting microbes
What microbes are catalase positive?
Aspergillus S. aureus Serratia Nocardia B. cepacia
What is the cause of Ischemia-Reperfusion Injury?
Caused by cytotoxic ROS derived from oxygen in the blood that re-perfuses previously hypoxic cells
What is the mechanism of Ischemia-Reperfusion Injury?
Insufficient O2 → decreased ATP → increased Na+ and Ca2+ levels
The reduced state of e- carriers in the absence of oxygen and loss of mitochondrial ion gradients or membrane integrity leads to what?
Increased superoxide production when oxygen becomes available during reperfusion
What is the typical isozyme of NADPH oxidase and where is the defect located?
- Generally has six different subunits (two in the cell membrane-alpha and beta) and four from the cytosol
- Genetic defect can be in any of four of these genes that encode these subunits
Catalase negative organisms generate enough hydrogen peroxide for what to occur?
Other highly reactive compounds are produced within the phagocytic vacuole of Chronic Granulomatous Disease neutrophils and macrophages, leading to effective microbial killing
