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strychnine is a _____?

rodenticide that was isolated from a plant

1

DDT is a ____?

organochlorine

2

what are general characteristics of organophosphates?

organophosphate = pesticide
degrades fast
used in flea collars, dips, fly, ant and roach bates

3

mechanism of action of organophosphates?

inhibits AchE causing cholinergic overstimulation

4

symptoms of anticholinesterase toxicity (organophosphates)

1. muscarinic (SLUDGE-M) - from excessive stimulation of GABA receptors
2. nicotinic receptors (responsible for shuttling ions back and forth across neurons and muscular junctions)
3. CNS - seizures

5

species specific symptoms of organophosphates (AChE inhibition)

horses = colic and dehdyration
ruminants = rumen stasis
dogs & cats = convulsions
cats = chlorpyrifos more nicotinic signs

6

how do you diagnose organophosphate (AchE inhibition) toxicity?

1. history and clinical signs
2. atropine challenge (if there is response to atropine its not OP toxicity)
3. decreased RBC AChE

7

treating organophosphate (AChE inhibition) toxicity

1. GI decontamination
2. atropine sulfate for muscarinic signs
3. oximes (protopam, 2-PAM) to reactivate AChE - bumps OP off AChE
4. diazepam
5. time

8

organophosphate-induced delayed neurotoxicity (OPIDN)

OP compounds that produce significant inhibition of neuropathy target esterase (NTE) which cause delayed neuropathy

9

what are symptoms of organophosphate-induced delayed neurotoxicity?

axonal degradation of long motor neurons - signs are hindlimb weakness and paralysis

10

what is the tx for organophosphate-induced delayed neurotoxicity?

none

11

general characteristics of ivermectin

- produced by soil fungus: streptomyces avermitils
- crosses the BBB!!
- collies, aussie shephards, shelties are super sensitive to ivermectin

12

what is fibrinil?

a GABA-A antagonist that works against roaches and is widely used

13

ivermectin: mechanism of action

GABA agonist

14

symptoms of ivermectin toxicity

mydriasis
respiratory depression
ataxia
coma
blindness
bradycardia

15

how to dx ivermectin toxicity

history
brain ivermectin concentration (>1000ppb)
can measure GI content, liver, fat and feces

16

treatment of ivermectin toxicity

GI decontamination (activated charcoal and saline cathartics)
short acting barbituates for convulsions
supportive care
epinephrine, fluids for anaphylaxis

17

what are mycotoxins

fungal metabolites that cause pathological, physiological and/or biochemical alterations usually on several organ systems simultaneously

18

slaframine - how is it produced?

by "black patch" fungus on red clover

19

where does slaframine toxicity generally occur?

central, south-east and south-west US where its humid, rainy and cool weather triggers growth

20

what is the MoA of slaframine?

it is an ACh mimic - acts primarily as a muscarinic cholinergic agonist especially in exocrine glands

21

symptoms of slaframine?

seen mostly in horses and cattle
"slobbers" - excessive salivation (sometimes only sign)
bloat, diarrhea, frequent urination
feed refusal

22

dx and tx of slaframine

dx by consumption, differentiate from OPs or botulism

tx by removing source, maintaining hydration and electrolytes, atropine

23

fumonisin is a metabolite of what?

fungas fusarium found on corn

24

what 3 isoforms does fumonisin form?

B1, B2, and B3 - B3 being most toxic

25

MoA of fumonisin

1. inhibits sphingosine-N-acteyltransferase causing increased levels of sphinganine which is cytotoxic.
- sphingosines are lipids that are important in cell signaling and integrity

2. affects vascular endothelial cells leading to stroke, hepatic injury and pulmonary edema.

26

what animals are susceptible to fumonisin?

horses, ponies, donkeys, swine and rabbits

27

what two diseases are linked to fumonisin?

equine leucoencephalomalacia (ELEM) and porcie pulmonar edema

28

porcine pulmonary edema: clinical signs

inactivity, increased respiratory rate, decreased HR, pulmonary edema within 4-7 days, respiratory distress

hepatic lesions consisting of apoptosis, necrosis and hepatocyte proliferation

29

porcine pulmonary edema: dx

1. analysis of feed
2. increase in serum and tissue sphingoid bases
3. increased ALT, ALP, GGT, total bilirubin, bile acids and cholesterol (indicating liver damage)