Environmental/toxicology cram Flashcards
Phase 1 and 2
Phase II biotransformation- In general, ingested chemicals are modified by the body to increase excretion and thereby limit toxic action. Chemicals modified by phase I reactions can be further metabolized by a variety of phase II reactions. Phase I metabolism includes oxidation, reduction and hydrolysis. Phase II reactions act to further increase hydrophilicity of the chemical, hastening its excretion. Phase II principally involves conjugation or synthesis reactions.
An alkaline toxin is excreted faster in acid urine.
An alkaline toxin is excreted faster in acid urine. Things are excreted better in an ionized state. An alkaline substance will be able to ionize when in acidic solution. When you suspect a child of having aspirin (acetylsalicylic acid) toxicity, you alkalinize the urine.
Toxins eliminated – protein bound/non-protein bound excreted the same?
Toxins eliminated – protein bound/non-protein bound excreted the same? No, lipid soluble toxins are passively reabsorbed. Only free compounds unbound by plasma proteins are filtered by the glomerulus. Tubular reabsorption-ionized and polar compounds are poorly reabsorbed they remain in the urine and are excreted.
IV administration of drugs is the quickest route of absorbtion, followed by:
IV administration of drugs is the quickest route of absorbtion, followed by:
IP, inhalation, IM, oral, SQ, ID and topical.
toxicant, toxin, toxicity, toxicosis/poisoning/intoxication
Toxicant- synonym for poison
Toxin- toxicant produced by living organism
Toxicity- amount of toxicant it takes to produce poisoning usually dose ie mg/kg
Toxicosis, poisoning, intoxication- disease state induced by toxicant
hazard, dose reponse, LC50, effectiveC50
Hazard- Likelihood of poisoning under conditions of use
Dose-response- any increase in dose will cause graded increase in response
LC50: dosage lethal concentration in 50% of animals,
LC50/EffectiveC50: Therapeutic Index
acute, subhronic, chronic
Acute toxicity- first 24 hrs (subacute 7-30 days)
Subchronic- <90 days (generally 30-90 days)
Chronic >90 days
half life, first order kinetics, zero order, lethal synthesis
Half life: time needed for ½ of a chemical to be eliminated. 20 ½ life periods will virtually eliminate chemical residues from the body.
First order kinetics: constant fraction per unit of time eliminated
Zero order kinetics: constant amount per unit of time eliminated
Lethal Synthesis: metabolized product may be more toxic than original compound
cat toxins
Cats lack gluconyl transferase therefore cannot metabolize phenols (aspirin, Tylenol)
atropine
Atropine- a sympathetic cholinergic blocking (antichloinergic) agent, a naturally occurring belladonna alkaloid, a parasympatholytic
2 PAM-
2 PAM- is a reactivator of acetylcholinerase.
GI toxins
GI: Blister Beetle, Mustard seeds, Corn, Cockle, Nightshade, Oleander, Castor bean (from which the very toxic RICIN comes from), chinaberry, tung, pokeweed, sesbania (coffee weed, bladder pod, rattlebox), azalea (rhododendron), baccaris (salt bush), Black locust, Hairy Vetch, Slaframine from fungus of Red Clove
Hematopoietic toxins
Hematopoietic system: Anemia &Hemoglobinuria, Bracken fern, Sweet clover (Meliotus), Cynanide, Cherry, Johnson Grass, Rye, Rape, Kale, Red Maple leaves, fresh onions
hepatic toxins
Hepatic: Aflatoxin, Lantana, Kleingrass, Zamia, Cotton, St Johnswort, Lupine, Cocklebur
Pyrrolizidine Alkaloids ragwort (Senecia jacobea), woolly groundsel (Senecia), Rattleweed (Crotalaria). Plants eaten in drought. Cattle, horses, pigs most susceptible Goats and sheep require 20 x more plant material
renal toxins
Renal: Black Locust, Quercus-oakbud, acorn poisoning, Oxalate-(beet, halogeton, greasewood, rhubarb, pigweed)
cardiovascular toxins
Cardiovascular: Cardiac glycoside containing: Milkweed, Laurel, Oleander, Dogbane, Lily of the Valley, Azalea, Foxglove. Japanese Yew, Jessamine, Halogeton, Pigweed, Oak, Digitalis, Jimsonweed, Gossypol (Cottonseed). Fungi: Ergot (Claviceps), Tall Fescue. White snakeroot; Rayless Goldenrod; Rhododendron
neuro toxins
Neurological: Seizure/tremors Bracken fern; Locoweed; Tremorgenic mycotoxins; Dallis grass; Ryegrass staggers, Centaurea spp- Yellow star Thistle & Russian Knap-weed, Poison Hemlock, water hemlock, nightshades, cycads, milkweeds
repro toxins
Reproductive Failure: Fescue forage prolonged feeding or grazing on endophyte-infected fescue during late pregnancy. Remove mares from fescue pastures or hay 6-8 weeks prior to foaling.
pulmonary toxins
Pulmonary: Locoweed, rumen microbes converting Tryptophan to 3 methylindole-“green grass sickness/Fog Fever”. Perilla mint, moldy sweet potatoes
Tetratogenic toxins
Tetratogenic:Lupine, poison hemlock, locoweed (astragalus) tobacco, lead tree, false hellbore
Mycotoxins that are teratogenic, cause abortion, infertility: rubratoxin, ochratoxin, slaframine, zearalenone, aflatoxin
Viruses that are teratogenic BVD, Blue tongue, akabane, and Ibaraki
Paspalitrems (ergot of Dallis Grass – Paspalum dilatatum) Cattle, Horses
Indol alkaloids are derivatives of LSD; inhibit GABA with signs of excitement, ataxia, tremors,
Slaframine (Red Clover or some other legumes infected with Rhizoctonia leguminicola) Cattle, Horses
Horses, Cattle
Slaframine has parasympathetic effects with production Called slobber factor, blackpatch. Signs: SLUD
T-2 Toxin
swine, Cattle, Sheep
Severe toxicosis characterized by leukopenia, petechiae, lymphoid and thymic depletion
Aflatoxins- Aspergillus flavus and parasiticus on peanuts, corn, soybeans
Primarily B1 most toxic seen in drought years,
Poultry, Ducklings most affected.
Baby pigs, calves, dogs. Signs- ADR, hepatitis, Chronic-wt loss, anorexic
Contaminated feed can be mixed with good feed to dilute. Can be fed to less affected animals.
Should not be fed to dairy cows. Residue in milk (M1) toxic at >300 ppb
Only aflatoxin is potentially detected by direct fluorescence, a yellow-green glow that results from a coincidental metabolite of Aspergillus flavus known as kojic acid.
Aflatoxin in corn- 40 ppm- action level is 20 ppm. What can farmer do to dispose of 50K bushels of corn? Ans: dilute to half with clean feed; feed to any livestock dairy no? mix with some chemical to reduce aflatoxin? No. FDA considers aflatoxins adulterants.
Algae Poisoning
Blue-green algae (cyanobacteria)
Anabeana, microcystis
Ruminants and birds more sensitive than monogastrics
Signs- dead w/ algae in mouth; in gut
ANTU Toxicity
alpha-napthlythiourea
Pets/livestock.
Signs- vomiting, HYPERSALIVATION, cough: PULMONARY EDEMA
Arsenic Poisoning
Trivalent (arsenite) 5-10 x more toxic
Pentavalent (arsenate) ant baits
activated charcoal; BAL (dimercaprol), sodium thiosulfate
Source: lead arsenate (pink powder) in storage areas, leaking herbicide containers, burned wood dumped in pasture, sweet ant baits