Toxicology Exam 2

Mycotoxin produced by the fungus Fusarium

fumonisin

Fumonisins produce what lesion in pigs

pulmonary edema

What organ does fumonisin target in horses

brain

What organ does fumonisin target in rats, rabbits, and sheep

kidney

What toxin produces liver damage in multiple species but targets specific organs in different species, like the lungs in pigs

fumonisin

A pig ingests moldy corn, fumonisin will cause decreased contractility and what sided heart failure in order to invoke pulmonary edema

left

3 toxins that cause peripheral vascular dysfunction

ergot, fescue, and black walnut

Claviceps purpurea is the name for what fungus

ergot

Ergot is a fungus that infects

grains

Ergonovine, Ergotamine, ergorpeptines are the toxic agents produced by

claviceps purpurea

Ergot causes toxic effects by working agonistically at biogenic amine receptors for

Epinephrine, serotonin, and dopamine

By working agonistically at epinephrine, serotonin, and dopamine receptors this produces what effect that leads to gangrene of extremities

vasoconstriction

A goat eats rye and later begins to have seizures, paralysis, and gangrenous extremities. A urine sample was collected and what toxin was found

ergot

The most common variety of tall fescue grass

kentucky 31

What fungal endophyte has a mutualistic relationship with tall fescue grass and protects it from pests by producing alkaloids

Neotyphodium coenophialum

3 toxic effects produced by the endophyte on tall fescue grass

vascular dysfunction, altered thermoregulation, and altered hormone regulation

Toxic agent of fescue

ergovaline

Ergovaline is an ergopeptine alkaloid produced by endophytes on what plant

tall fescue grass

A cow is seen panting, drooling, not eating, not shedding, not moving, with heavy respirations and a gangrenous foot and spending a lot of time in the water. What toxin did they get into

fescue grass

What is the most prevalent alkaloid in fescue

ergovaline

A horse develops laminitis after the owner changes the bedding in it’s stall to

black walnut shavings

Main toxic component of black walnut

juglone

Juglone is absorbed through

the skin and coronary band

Juglans nigra

black walnut

How do you treat black walnut toxicity

remove from source and NSAIDs

Warfarin is an anticoagulant drug that works by inhibiting

vitamin K reductase

Vitamin K dependent coagulation factors

X, IX, VII, II

Molding of sweet clover promotes the likelihood that what will form in the hay

dicoumarol

First generation anticoagulants require how many feedings to produce toxicity

multiple

What generation anticoagulant is warfarin

1st

Intermediate anticoagulants are more toxic than 1st generation anticoagulants because

they require fewer feedings

What is an example of an intermediate anticoagulant

diphacinone

2nd generation anticoagulants are highly toxic to nontarget species after how many feedings

1

What is an example of a 2nd generation anticoagulant

brodifaucoum

Which is the most potent anticoagulant brodifacoum, bromethalin, diphacinone, or warfarin

brodifacoum

What is the antidote to anticoagulant rodenticides

vitamin K1

Can owners treat rodenticide poisonings with OTC vitamin K1

No, it is insufficiently potent to be effective

Examples of alliums

garlic, onion, leeks, chives, scallions, and shallots

Alliums contain what toxic component

organosulfoxides

Chewing alliums converts organosulfoxides into

a complex mix of sulfur-containing organic compounds

Toxic doses with alliums are

just approximations and variable

Alliums cause damage to RBCs via

oxidative hemolysis

Hemoglobin in what species is 2-3x more suscpetible to oxidative damage by alliums

cats

Catalase antioxidant activity in RBCs is low in what species and therefore makes it easier for alliums to cause oxidative damage

dogs

Heniz bodies form after the consumption of alliums because

sulfhemoglobin is less soluble and therefore precipitates, aggregates, and binds to the cell membrane

Oxidative injury to RBCs and the formation of Heinz bodies by sulfur-containing organic compounds

allium toxicity

If a dog eats pennies past 1983, what kind of toxicitiy are you worried about

zinc

Regenerative hemolytic anemia, hemoglobinuria, but no methemoglobinemia in a dog that has ingested pennies

zinc toxicity

APAP is an abbreviation for

acetaminophen

Acetaminophen is metabolized where

liver

Glucoronidation is very important for metabolizing acetaminophen, which species does very little glucoronidation

cats

2 toxic metabolites of acetaminophen

NAPQI, PAP

Very reactive toxic metabolite of APAP

NAPQI

NAPQI is usually conjugated with what so that it is rapidly eliminated and does not cause toxicity

glutathione

What APAP metabolite causes oxidative stress

PAP

Why are cats more sensitive to acetaminophen toxicity

they lack glucuronidation

Excess APAP overwhelms sulfation, glucuronidation, and glutathione pathways leading to

excess NAPQI, increased PAP, and depletion of glutathione

Primary toxic metabolite of acetaminophen

NAPQI

The biggest problem associated with acetaminophen toxicity in dogs

hepatic injury

The biggest problem associated with acetaminophen toxicity in cats

hematologic injury

Facial/paw edema, brown blood, cyanosis, heinz bodies in cats

acetaminophen toxicity

Treatment for acetaminophen toxicity

N-acetylcysteine

How does N-acetylcysteine treat acetaminophen toxicity

replaces glutathione stores, enhances detoxification of NAPQI, decreases oxidative stress, and lessens potential for liver injury

60-80% of blood supply to the liver

portal vein

20-40% of blood supply to the liver

hepatic artery

The portal drains blood from the GIT into the

liver

Which liver zone is the least oxygenated

centrilobular zone (3)

Which liver zone is the most oxygenated

Periportal zone (1)

Which zone of the liver is the 1st to encounter toxins from the GIT

periportal zone (1)

Liver zone that is most susceptible to hypoxia

Centrilobular zone (3)

Area of the liver where most metabolic transformation takes place

centrilobular zone (3)

1st pass effect

things absorbed by the GIT pass through the liver 1st before systemic circulation

The liver is exposed to the highest concentration of toxin from the GIT because of the

1st pass effect

Bioaccumulation of metals and vitamins occurs in what organ

liver

High levels of iron in zone 1 of the liver

lipid peroxidation

Bedlington terriers are genetically known for buildup of what in the liver

copper

Enterohepatic recycling

the liver is exposed to the same toxin over and over again because the liver is supplied by the portal vein which drains blood from the GIT into the liver, and then the liver secretes bile into the GIT

Bioactivation and metabolism occur in what zone of the liver

centrilobular zone (3)

Focal necrosis

randomly distributed individual hepatocytes or clusters

Zonal necrosis typically occurs where

Centrilobular zone

Bridging necrosis

confluent zones of necrosis that extend between zones of the lobule and between lobules

Panlobular or massive necrosis

hepatocyte loss throughout the lobule with loss of lobular architecture

Consumption of senecio and crotalaria cause exposure to what hepatotoxin

pyrrolizidine alkaloids

What kind of animals are highly resistant to pyrrolizidine alkaloids

small ruminants, rabbits, and guinea pigs

Why are small herbivores resistant to pyrrolizidine alkaloids

associated with a low rate of production of reactive metabolites and a high rate of activity of detoxifying enzymes

Primary effect of crotalaria

pulmonary damage with hepatic effects

Toxic principle of crotalaria

monocrotaline and spectabiline

Crotalaria is a soil builder that supports nitrogen fixing bacteria and contains what hepatotoxin

pyrrolizidine alkaloids

Which is worse the pulmonary or hepatic damage caused by crotalaria

pulmonary

Tansy ragwort

senecio

Showy rattlebox

crotalaria

Senecio contains what hepatotoxin that causes liver necrosis in cattle

pyrrolizidine alkaloids

Where are pyrrolizidine alkaloids metabolized

liver

Potent electrophiles that react with DNA, proteins, and AAs

pyrrolizidine alkaloids

Acute liver failure, anorexia, depression, icterus, edema is what kind of pyrrolizidine alkaloid intoxication

acute

Photosensitivity, icterus, and increased susceptibility to other liver insults details what kind of pyrrolizidine alkaloid intoxication

chronic

Is there any treatment for pyrrolizidine alkaloid intoxication

no

A cow presents with increased liver enzymes, bilirubin, and hepatic necrosis with fibrosis and biliary proliferation, photosensitivity, icterus, and there is no treatment for this intoxication. What toxin did the cow get into and how long ago?

chronic intoxication with pyrrolizidine alkaloids

What are 2 types of plants that contain pyrrolizidine alkaloids

crotalaria and senecio

You should not attempt to identify the type of mushroom because it can be very dangerous and invite liability. In most cases how will you deal with mushroom intoxications

decontaminate, monitor for clinical syndromes, and treat accordingly