Test 4: 45 principles part 1

Question 1

most common toxins of tremorgenic mycotoxins

Answer 1

penitrem A (moldy walnuts)
roquefortine C (soft cheeses)

at least 20 mycotoxins have been identified as tremorgens- most commonly associated with penicillium species

Question 2

tremorgenic mycotoxins cause intoxication in what type of animals

Answer 2

a bunch

dogs, cattle, sheep, rabbits, rodents, poultry

molds that lead to tremors

Question 3

how does tremorgenic mycotoxins work

Answer 3

several proposed theories

May vary both between specific toxins and individual susceptible species

• Penitrem-A inhibits the inhibitory neurotransmitter glycine in mice
• Another tremorgen, verruculogen, reduces concentrations of GABA in the brain

Question 4

treatment for tremorgenic mycotoxins

Answer 4

Diazepam and methocarbamol

if not responding to diazepam: barbiturates (pentobarbital)

Question 5

how to decontaminate tremorgenic mycotoxin intoxication

Answer 5

sedate and gastric lavage if pt has not vomited

activated charcoal and a cathartic

sedation will decrease risk of tremor and ET tube will prevent aspiration

Question 6

general treatment for tremorogenic mycotoxin poisoning

Answer 6

• Thermoregulation
• Treat for shock
• Intravenous fluid support
• Prognosis good with early and aggressive treatment
• No long-term sequelae expected

Question 7

1947 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA): Non-food, non-drug substances had to be shown to be —

Answer 7

safe and efficacious

Question 8

alternate term for poison, any agent capable of producing a deleterious response in a biological system

Answer 8

toxicants

Question 9

poison that originates from biological processes

Answer 9

toxin

Question 10

Toxicity vs toxicosis

Answer 10

Toxicity = quantity or amount that causes a toxic effect

Toxicosis = disease state that results from exposure to a poison

Question 11

threshold dose vs LD50 vs median lethal dose

Answer 11

Threshold dose = highest dose of toxicant at which toxic effects are not observed

Lethal dose 50% or LD50 = the dose at which 50% of the animals die

Median lethal dose (MLD) = used interchangeably with LD50

Question 12

NOEL and NOAEL

Answer 12

no observed effect
level

no observed adverse effect level

Question 13

LOEL and LOAEL

Answer 13

LOEL: lowest observed effect level

LOAEL: lowest observed adverse effect level

Question 14

the — the therapeutic index, the safer the chemical

Answer 14

larger

TI= LD50/ED50

if large number, there is a wide dose that can be given before toxic effects

Question 15

the smaller the standard safety margin the — the chemical

Answer 15

more dangerous

SSM= LD1/ED99

standard safety margin (SSM)= margin of safety (MoS)

Question 16

chronic toxic effects may occur if chemicals —, toxic effects products are — or there is — between exposures

Answer 16

accumulate

irreversible

insufficient recovery time

Question 17

additive effect vs synergistic effect

Answer 17

additive: 2+3=5

synergistic: 2+3=20 (greater than the sum of the individual, occur if one chemical affects the solubility, binding, metabolism, or excretion of
the other

Question 18

potentiation

Answer 18

one otherwise non-toxic or only mildly-toxic chemical enhances the toxicity of another chemical

0 + 2 = 20

• Isopropanol is not hepatotoxic, however enhances the hepatotoxicity of carbon tetrachloride

Question 19

antagonism can work in three ways

Answer 19

Physiologic – epinephrine antagonizes hypotensive effects of phenobarbital

Chemical – calcium EDTA complexes with lead

Metabolic – ethyl alcohol competes with ethylene glycol (EG), preventing EG’s activation to toxic metabolites

Question 20

for dose response what three assumptions are made

Answer 20

• The chemical interacts with a molecule or receptor site to produce a response
• The production of the response, or degree of response, is correlated to concentration of the chemical at that receptor site
• The concentration of the chemical at the receptor site is related to the dose of chemical received

Question 21

hormesis

Answer 21

Some xenobiotics impart beneficial or stimulatory effects at low doses but have adverse effects at higher doses

selenium, Vit A

Question 22

cadmium will cause – is ingested, inhaled or touched

Answer 22

Oral exposure → renal lesions

Inhalation exposure → lungs 1st +/- kidneys

Dermal exposure → produces little if any toxicity

Question 23

Felines possess limited —capabilities, so must rely on the less- efficient sulfate & cysteine conjugation pathways compared to dogs

Answer 23

glucuronidation

Question 24

why are young animals usually more susceptible to toxins

Answer 24

• GI mucosa and blood-brain barrier are less developed
• Drug-metabolizing enzymes are generally less active
• Higher proportions of body water and lower proportions of body fat influence distribution and storage of drugs and chemicals