Toxicants Affecting the Circulatory & Hematopoietic Systems (11) Flashcards
What are fumonisins?
mycotoxins produced by the fungus fusarium overticillioides
What does fumonisin induce in pigs?
porcine pulmonary edema
inhibits L type Ca2+ channel which decreases myocardial contractility = L-sided heart failure = pulmonary edema
What organ do fumonisins primarily target in pigs? Horses?
pigs: lungs
horses: brain
What are major factors in the content of ergot containing grain?
growing conditions
storage
What are the toxic principles in ergot toxicity?
ergonovine
ergotamine
lysergic acid amides
ergopeptines
What is the mechanism of toxicity of ergot?
acts agonistically at biogenic amine receptors in the animal’s body
Which molecules does ergot mimic in the body?
NE & epinephrine, dopamine, serotonin
What are clinical signs of ergot toxicity?
convulsions, hallucinations, abortion, paralysis, GI disturbance, gangrene of extremities
affects level of coronary band
What is fescue toxicity?
infected by the endophyte Neotyphodium coenophialum
How is fescue toxicity different than ergot toxicity?
fescue has an endophyte growing into the plant while ergot is on the outside
What is the most prevalent ergopeptine in fescue toxicity?
ergovaline - 90%
also have ergonovine and ergo line alkaloids
Why do cattle migrate to water with fescue toxicity?
ergovaline causes vasoconstriction (alpha-adrenergic) which makes them harder to regulate their body temperature
What is fescue foot?
having hoof lesions primarily at the coronary band because of blood supply
What is the toxin in black walnut?
juglone
What is the MOA for black walnut and which species does it affect? What does it cause?
wood shavings used for bedding for horses —> absorbed through then coronary band and skin
laminitis
horses
Blood and bone marrow toxicity may be a result of ____
off-target inhibition, leading to decreased bone marrow response or a result of peripheral effects
leads to destruction of blood cells
ROS - react with cells.ar proteins, lipids, other molecules = hemolysis
What happens with Warfarin toxicity?
interferes with the clotting cascade
blocks vitamin K reductase
What happens with warfarin blocking vitamin K reductase?
remains at oxidized form of vitamin K
How do you treat rodenticide toxicity?
add reduced version of vitamin K
What is the toxic agent in sweet clover?
coumarin —> dicoumarol which acts similar to warfarin and is an anticoagulant
All anticoagulants have the basic ____ and ______ nucleus
coumarin
indanedione
What do first generation anticoagulants require?
multiple feedings to result in toxicity
warfarin, pinion, coumafuryl, coumachlor
What do “intermediate” anticoagulants require?
fewer feedings than “first generation” chemicals, and thus are more toxic to non target species
diphacinone
What are characteristics of “second generation” anticoagulants?
highly toxic to non target species after a single feeding
ex. single feeding could kill rat
What is the toxic principle in allium plants?
Trauma to the plant, like chewing, converts organosulfoxides to a sulfur-containing organic compounds
What is the toxicologic mechanism for allium toxicity?
oxidative hemolysis, which occurs when the concentration of oxidants in the erythrocyte exceeds the capacity of the antioxidant metabolic pathways
causes oxidative hemolysis, red blood cells break up → Hb released → hemolytic anemia
Why are allium spp. so toxic to dogs? Cats?
Dogs: catalase antioxidant activity in erythrocytes is low
Cats: 2-3x more susceptible to oxidative damage than the Hb in other species
What does Allium form on red blood cells? Why?
Heinz bodies
sulfhemoglobin is less soluble than hemoglobin, so it precipitates, aggregates, and binds to the cell membrane
How does one get zinc toxicity?
What is the mechanism of toxicity of acetominophen in cats?
normally is metabolized by the UDP-glurcuronosyl transferase, but cats DO NOT have glucoronidase, so goes through the cytochrome P-450 pathway and is converted into N-acetyl-p-benzoquinoneimine which is toxic
In acetaminophen toxicity, what regenerates glutathione (GSH)?
N-actyl cysteine
