Toxicology

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Transcript Toxicology

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Substances that kill at high doses are actually
beneficial at low doses
 Arsenic – growth deficiency without it, syphilus,
cancer
 Clostridium botulinum - Botox
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Earliest use of poison was for
Socrates’ execution in 339 BC
Arsenic was most common
because it left no trace and
resembled death by natural
causes.
“Traite des poisons” by Mathieu
Orfila in 1814 gave first systematic
approach to identifying poisons in
the body.
James Marsh developed test to
detect arsenic in body tissues and
fluids.
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Dosage
Chemical or physical form of substance
How it enters the body
Body weight and physiological conditions of
the victim, age, and sex
Time period of exposure
Whether other chemicals are present
(synergism and antagonism)
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Use animals to get estimates
LD50 is the lethal dose for half of the
population within 4 hours (mg substance/kg
body weight)
Regulatory agencies
 FDA, EPA, Consumer Product Safety Commission,
DOT, OSHA
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Subtle brain damage, memory loss, faulty
thought processes
Most common exposure is through leadbased paints (banned in 1978)
2 tests for lead
 Reaction of dissolved lead with sulfide ion to form
insoluble, brown-black lead sulfide
 Reaction with an organic complexing agent,
sodium rhodizonate, to make a pink color
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Other sources: lead pipes, soil, leaded gas
(banned in 1995)
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Less than one half of 1% of all homicides are a
result of poison
Common poisons today are arsenic, cyanide,
and strychnine
Acute poisoning – high dose over short
period of time
Chronic poisoning – low dose over long
amount of time
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More common than poisonings
 John Belushi, Chris Farley, River Phoenix, Janis
Joplin, Jim Morrison, Jimi Hendrix, Marilyn
Monroe, Heath Ledger, Anna Nicole Smith
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Organic - Venom
 Snakes, bees
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Alcohols
Bacterial Toxins
 Botulism (neurotoxin), Clostridium tetani
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Heavy Metals and Pesticides
Bioterrorism Agents
 Ricin (waste product of castor oil)
 Anthrax (Bacillus anthracis)
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Most abused drug in America
40% of all traffic deaths are alcohol related
Ethanol affects the CNS
BAC ist he amount of alcohol in the blood
Present BAC limit is 0.08% so .08 grams of
alcohol for every 100 mL of blood
Average removal rate is 0.015% per hour
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BAC (male) = 0.071 x (volume consumed, oz)
x (% alc.)/body weight
BAC (female) = 0.085 x (volume consumed,
oz) x (% alc.)/body weight
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1 mL of blood contains as much alcohol as
2,100 mL of breath (based on Henry’s Law)