FREE RADICAL INJURY, AMYLOIDOSIS Flashcards
(29 cards)
What are free radicals?
Chemical species with an unpaired electron in their outer orbit.
How are free radicals physiologically generated?
During oxidative phosphorylation, where cytochrome c oxidase transfers electrons to oxygen.
What are the types of oxygen free radicals?
Superoxide (O2ꜙ), hydrogen peroxide (H2O2), and hydroxyl radicals (˙OH).
What pathological conditions generate free radicals?
Ionizing radiation, inflammation, metal toxicity (Fe2+), and drug metabolism via the P450 system.
How do free radicals cause cellular injury?
By peroxidation of lipids and oxidation of DNA and proteins, leading to aging and oncogenesis.
What mechanisms eliminate free radicals?
Antioxidants, enzymatic breakdown (superoxide dismutase, glutathione peroxidase, catalase), and metal carrier proteins.
What is the role of superoxide dismutase?
It converts superoxide (O2ꜙ) into hydrogen peroxide (H2O2).
What is glutathione peroxidase?
An enzyme in mitochondria that detoxifies free radicals using glutathione.
What is the role of catalase?
It breaks down hydrogen peroxide (H2O2) into water and oxygen.
What is carbon tetrachloride (CCl4) toxicity?
CCl4 is converted to CCl3 free radical in the liver, causing liver damage and fatty change.
What is reperfusion injury?
Reoxygenation of ischemic tissue generates free radicals, leading to further damage.
What is amyloidosis?
A disorder where misfolded proteins deposit in extracellular spaces, damaging tissues.
What are the common features of amyloid proteins?
Beta-pleated sheet configuration and Congo red staining with apple-green birefringence under polarized light.
What are the types of amyloidosis?
Systemic (primary and secondary) and localized amyloidosis.
What is primary amyloidosis?
Systemic deposition of AL amyloid derived from immunoglobulin light chain, often linked to multiple myeloma.
What is secondary amyloidosis?
Systemic deposition of AA amyloid derived from serum amyloid-associated (SAA) protein.
What conditions increase SAA protein levels?
Chronic inflammation, malignancy, and Familial Mediterranean Fever (FMF).
What are the symptoms of systemic amyloidosis?
Nephrotic syndrome, restrictive cardiomyopathy, tongue enlargement, malabsorption, hepatosplenomegaly.
What is the most commonly involved organ in amyloidosis?
The kidney.
How is amyloidosis diagnosed?
Tissue biopsy (abdominal fat pad or rectal biopsy) with Congo red staining.
What is the treatment for amyloidosis?
Damaged organs must be transplanted; amyloid deposits cannot be removed.
What is senile cardiac amyloidosis?
Non-mutated transthyretin deposits in the heart, usually asymptomatic.
What is familial amyloid cardiomyopathy?
Mutated transthyretin deposits in the heart, leading to restrictive cardiomyopathy.
What is the prevalence of familial amyloid cardiomyopathy?
5% of African Americans carry the mutated gene.
