Toxicity: General, Solvents, Metals

Question 1

What is the mechanism of toxicity for OP pesticides? What enzyme do they inhibit? What neurotransmitter builds up? What are some s/s?

Answer 1

OPs inhibit AChE; which causes a buildup of ACh –> overstimulate receptors –> anxiety, seizures, tremors, emotional lability, visual disturbance, bronchospasm, arrhythmia, diarrhea

Question 2

What is the mechanism of toxicity for cyanide? It inhibits enzymes involved in what process? In what location? What necessary product can affected cells not produce?

Answer 2

CN inhibits enzymes involved in oxidative phosphorylation in the mitochondria. As a result, these cells cannot produce ATP.

Question 3

In general, what is the acute mechanism of toxicity for solvents?

Answer 3

Disrupt nerve cell membrane –> respiratory depression

Question 4

Alkanes; ex: pentane
Lipophilic or Hydrophilic?
What are liver (1) and nervous system (1) effects of chronic exposure?

Answer 4

Alkanes; ex: pentane
Lipophilic
liver necrosis; polyneuropathy

Question 5

Aromatic Hydrocarbons; ex: benzene, toluene, xylene
Describe their hemotoxic effects.
Which example is carcinogenic?

Answer 5

Aromatic Hydrocarbons; ex: benzene, toluene, xylene
destroy bone marrow, causing aplastic anemia
benzene –> leukemia

Question 6

Glycol Ethers; ex: ethyl cellusolve; butyl cellusolve
low vapor P; high H2O solubility;
Describe toxic effects related to nervous system (5) and hematology (1).
What other organ system does this class target?

Answer 6

Glycol Ethers; ex: ethyl cellusolve; butyl cellusolve
low vapor P; high H2O solubility;
demyelination; h/a; personality disorder; lethargy; blurred vision; aplastic anemia; reproductive effects

Question 7

Ketones; ex: MEK, MIBK

Describe CNS-related toxicity (6); peripheral neurotoxicity (2); and toxicity related to hexane (1)

Answer 7

Ketones; ex: MEK, MIBK
CNS: CNS depression, h/a, nausea, ataxia, lethargy, speech
PNS: peripheral neuropathy; polyneuropathy; potentiate hexane neurotoxicity

Question 8

Alcohols; ex: methanol, ethanol; CNS depressants; Describe hepatotoxicity (2); fetal toxicity (which alcohol?); visual toxicity (which alcohol?); toxicity related to chlorinated hydrocarbons

Answer 8

Alcohols; ex: methanol, ethanol; CNS depressants;

Fatty liver, cirrhosis; FAS (ethanol); blindness (methanol); potentiate chlorinated hydrocarbon toxicity

Question 9

Chlorinated Hydrocarbons; ex: chloroform, CCl4, TCE; non-flammable, high vapor P (intrusion); describe hepatotoxicity (2); cancers (2); fetal toxicity

Answer 9

Chlorinated Hydrocarbons; ex: chloroform, CCl4, TCE; non-flammable, high vapor P (intrusion); livery necrosis + fatty liver; kidney + liver cancer; mildly teratogenic

Question 10

Arsenic; Uses include smelting, paint pigment, and (2) others?; naturally occurs where (2)?; Which form is toxic? What enzymes does it affect?

Answer 10

Arsenic; smelting, paint pigment, firing agent, wood preservative; occurs in seafood, groundwater; trivalent form is toxic; hits mitochondrial respiratory enzymes

Question 11

Arsenic; Describe hepatotoxicity (2); carcinogenicity (4); and other systems targeted (4)

Answer 11

Arsenic; jaundice + cirrhosis; carcinogenic @ skin, lung, liver, leukemia; also toxic @ cardiac, renal, vascular, and neuro

Question 12

Cadmium; uses include smelting, paint pigment, batteries, and (2) others? High uptake via which route? Describe destination, accumulation and half-life.

Answer 12

Cadmium; uses include smelting, paint pigment, batteries, electroplating, galvanizing; High uptake via inhalation; binds to RBCs, accumulates in liver/kidney; long half-life (30y)

Question 13

Cadmium; Describe lung toxicity (2); What other (4) systems affected, including (1) unique disease?

Answer 13

Cadmium; COPD + lung cancer; nephrotoxicity + hypertension + digestive effects + “itai-itai” (skeletal)

Question 14

Lead; uses include paint, batteries, fuel additive, and (2) others? Exposure via lead paint what other source? Binds to RBCs and has what (3) destinations?

Answer 14

Lead; uses include paint, batteries, fuel additive, solder, nuclear shielding; Binds to RBCs, can deposit in skeleton, brain, and cross placenta

Question 15

Lead; describe neurotoxicity (3), enzyme inhibition (1), and what other (2) toxicity targets?

Answer 15

Lead; peripheral neuropathy (sub Pb for Ca), encephalopathy, IQ impairment; inhibits delta ALA; targets hearing + kidney

Question 16

Mercury; sources include burning fossil fuels, mining, and (1) other?; What is the major toxic form?; uses include switches, thermostats, thermometers, and what extractant use?

Answer 16

Mercury; sources include burning fossil fuels, mining, and degassing of crust; major toxic form: methyl mercury from bacteria; uses include switches, thermostats, thermometers, gold purification

Question 17

Elemental Hg can vaporize and target what system?; methyl mercury exposure via what route?; describe CH3-Hg accumulation; describe CH3-Hg targets (2)

Answer 17

Elemental Hg vaporizes, targets CNS; CH3-Hg exposure via ingestion; CH3-Hg does not accumulate (70d t1/2); hits brain, cross placenta

Question 18

Hg salts cause renal necrosis and what (3) GI effects?

Answer 18

Hg salts: renal necrosis, cramping + diarrhea + gastric bleeding

Question 19

Methyl mercury toxicity from chronic fish ingestion causes what unique disease? It causes fetal toxicity; describe neurotoxicity (6)

Answer 19

CH3-Hg toxicity from chronic fish ingestion –> Minimata Disease; numbness, ataxia, fatigue, vision/hearing impairment, tremor