Environmental and Nutritional Diseases Flashcards
R&C Ch 9
Phase I reactions; most important catalyst; outcome
Hydrolysis, Oxidation, Reduction; Cytochrome P-450 enzyme system; Detoxify or convert into active compounds
Phase II reaction, and outcome
Glucuronidation, sulfation, methylation, conjugation with glutathione (GSH); form water-soluble compounds
What do CYPs contain? Where do they live?
Heme; mostly hepatocytes, in SER
What do CYPs do (two possibilities)? What by-product is produced?
Either detoxify xenobiotics or convert them to active compounds; ROS
What does lead bind to? What does it do? What are effects?
Binds sulfhydryl groups in proteins; interferes with calcium metabolism; Blood, skeletal, neuro, GI, renal toxicities
How does lead affect blood?
Interferes with heme synthesis and incorporation of Fe into heme, so microcytosis and anemia, and interferes with ATPases, so hemolysis
What does mercury bind to? What does it do? What are effects?
Binds sulfhydryl group in certain proteins; CNS demyelination and AKI, so CNS and renal toxicity
What does arsenic bind to? What does it do? What systems are affected?
Binds cytochrome C, interfering with cellular metabolism; GI, nervous, skin, heart
What does cadmium do? What systems are affected
Increases production of ROS (cause unknown); Kidneys and lungs***
Most of acetaminophen is detox’d by what? Excreted how?
Phase II enzymes; urine
Rest of acetaminophen is metabolized by what? Into what?
CYP to NAPQI
What happens to NAPQI normally? What happens with acetaminophen toxicity?
NAPQI normally conjugated with GSH
Unconjugated NAPQI accumulates, causing hepatocellular injury
How does NAPQI cause injury?
Binds proteins which damages cell membranes, depletes GSH, so hepatocytes more susceptible to ROS
How does aspirin cause injury?
Acetylates platelet COX, blocking the production of thromboxane A2 irreversibly, so decreased clotting
Stimulates respiratory center to cause respiratory alkalosis
Superficial
Partial-thickness
Full-thickness burns
Superficial- confined to epidermis
Partial-thickness- injury to the dermis
Full-thickness burns- extend to subcutaneous tissue
What causes malignant hyperthermia?
Mutations in RYR1 (ryanodine receptor) leading to rapid release in calcium levels and muscle contraction and heat production
Nonionizing radiation vs ionizing
Nonionizing- UV rays, infrared light
Ionizing- X rays, gamma rays, particles; removes electrons, so damages DNA
Ionizing causes chromosome breakage and translocations
Which vitamins are fat soluble? What’s the implication of this?
A, D, E, K; More readily stored in body
Three major functions of vitamin A
Vision
Regulation of cell growth and differentiation
Lipid metabolism
Where is most vitamin A stored?
In Ito cells in the liver
Vitamin A metabolism
Absorbed by enterocytes, transported to liver in chylomicrons, Apolipoprotein E receptor stimulates uptake in hepatocytes, transported to tissues by retinol binding protein
Vitamin A deficiency causes
Night blindness, squamous metaplasia
Vitamin A toxicity causes
Bone pain, fractures, teratogenic
Purpose of vitamin D
Maintain plasma Ca and phosphorus
