CC: HMPS, RBC Oxidation and Anemia

Question 1

What happens to RBCs in the lungs with respect to oxidation?

Answer 1

RBCs are exposed to high amounts of Free Radical in the lungs as well as the arterial system.

Question 2

What two parts of the RBC are affected by oxidative damage?

Answer 2

Membrane and Hemoglobin (pretty much all that they’re made up of)

Question 3

What happens when oxygen is exposed to fatty acids (fats in general)?

Answer 3

Hydrogen Peroxide formation.

Question 4

What happens to oxygen when it receives an extra electron?

Answer 4

Superoxide anion

Question 5

What happens when H2O2 is combined with Superoxide anion?

Answer 5

Hydroxyl Radical - really bad ass

Question 6

What happens when Fe++ (normal hemoglobin iron) is exposed to H2O2?

Answer 6

Fe+++ (methemoglobin) and hydroxyl radical formation.

Methemoglobin tends to precipitate too ==> Heinz Bodies

Question 7

What are Heinz Bodies?

Answer 7

precipitated Methemoglobin in RBCs

Question 8

How can you reverse some of the damage from methemoglobin (Fe+++) damage?

Answer 8

Methemoglobin (Fe+++) reductase use NADH to get back to Hemoglobin (Fe++)

Question 9

What is the typical result of damage to RBCs?

Answer 9

Hemolytic Anemia

Question 10

What causes Heinz Body formation specifically in Horses? (other things do too)

Answer 10

Red Maple Leaves

Question 11

What do onions and garlic do to an animal?

Answer 11

Heinz Body formation in Horses, Cows, Cats, Dogs and Primates (yes us too!)

Question 12

Why should you not give acetaminophen to cats? (with respect to this topic)

Answer 12

Heinz Body formation –> hemolytic anemia

Question 13

What does propylene glycol do to cats? Why would this be an issue in their diet?

Answer 13

Heinz Body formation –> hemolytic anemia

It was used as a humectant to keep food moist but was banned from cat foods by the FDA in 1996.

Question 14

What does superoxide dismutase do?

Answer 14

It takes the oxygen radical and makes H2O2 and Oxygen.

Question 15

How does the body protect against H2O2?

Answer 15

CATALASE takes H2O2 and makes oxygen and water.

Question 16

How does Glutathione Peroxidase protect the body against oxidative damage?

Answer 16

It can perform 2 reactions:
H2O2 + Glutathione –> Water and GSSG

Lipid-OOH (oxidative damage to lipid) + Glutathione –> Lipid-OH (not perfect, but less damaged) + GSSG + Water

Question 17

How does Glutathione Reductase protect the body against oxidative damage?

Answer 17

using NADPH it will break GSSG back to GSH/Glutathione so it (Glutahione) can continue to protect against oxidative damage via Glutathione Peroxidase.

This uses a cofactor FAD which is different from the FAD we know and love in TCA Cycle/ETC.

Question 18

How is Glutathione (GSH) made? Where does it come from?

Answer 18

Glutamate + Cysteine + ATP –> gamma-Glutamylcysteine + Glycine + ATP –> Glutathione.

It now has a free sulfhydryl group which is used in antioxidant defense system.

Question 19

What would you expect from a Glucose-6-Phosphate Dehydrogenase deficiency?

Answer 19

It is the first enzyme in HMPS: can’t make NADPH!!!

Cannot restore Glutathione back to its original reduced state –> messes up antioxidant defense system ==> HEMOLYTIC ANEMIA

Question 20

What seemingly harmless drugs cause G-6-PDH deficiency? (Eng question)

Answer 20

antimalarials, antipyretics, sulfa antibiotics

These drugs work on sulfhydryl/disulfide bonds.

Question 21

What’s up with rabbits and this enzyme G-6-PDH?

Answer 21

They have LOW levels to begin with.

Acetylphenylhydrazine and Primaquine Phosphate are BAD for rabbits

Question 22

What inhibits G-6-PDH in sheep liver?

Answer 22

Penicillin, Cefazolin, Sulbactam, amikacine

Question 23

How come Fava Beans are bad?

Answer 23

Animals deficient in G-6-PDH are prone to fava bean poisoning

Question 24

What is the potential effect on PCV hematocrit with a thiamine/B1 deficiency?

Answer 24

Lowers it –> Hemolytic anemia = less RBCs = lower PCV