metals Flashcards
what are the 3 major heavy metals
lead
arsenic
mercury
“LAM”
4 classifications of metals
-greatest toxicologic significance
-essential trace metals
-biological interest
-pharmacological interest
group 1A on the periodic table
they are essential elements
however, excess intake can induce toxicity
group IIA on the periodic table
basically nontoxic
(but beryllium causes lung fibrosis)
group IB on periodic table
basically nontoxic
group IIB on periodic table
strong covalent bonds - have affinity for thiol
2 kinds of therapy for heavy metal toxicity
chelators and compounds with a thiol group
which is the more toxic form of arsenic:
As2O3
As2O5
As2O3
4 chelating agents
EDTA
DMPS
DMSA
Tiron
how are EDTA and DMPS administered
IV
how is DMSA administered
orally
chelators ____ the excretion of lead
promote
chelators are drugs that supply the ____ group for heavy metals to be eliminated from the body
thiol
chelators bind heavy metals in which compartment
vascular - prevent it from reaching the organs
which heavy metal is the most significant toxin
LEAD
added to paint, dyes, gasoline, etc
lead poisoning is defined as >____mcg/deciliter of blood
10
___lead toxicities tend to PREDOMINATELY affect the CNS
organic
inorganic can too, but also affects other systems
differentiate between how organic vs inorganic forms of lead are absorbed
inorganic - ingestion or inhalation
organic - through the skin
only about ___% of an ingested dose of lead is absorbed in adults, and as much as ___% in children
10% adults
50% children
lead absorption is enhanced by deficiencies in….
iron, calcium, and zinc
____lead cations can pass the BBB and cause neurotoxicity
organo
which form of lead is biotransformed and which isnt
inorganic is NOT metabolized
organic is – by oxidative dealokylation
true or false
lead gets into multiple enzyme systems
true
lead inteferes with the production of ___ due to the presence of the sulfhydryl group
heme
gold standard for monitoring lead toxicity
blood lead level
lead accumulates in ____ and interferes with the enzyme ____
RBC
ferrocheletase
how to tell the growth of bones has been slowed by lead toxicity
lead lines on the bone
lead absorption in increased when a diet rich in ___ is consumed
FATS
also, low in iron, calcium, vitamin C
only metal that is liquid at room temp
mercury
mercury is toxic in ANY FORM, but which form is the most toxic?
organic mercury
4 symptoms of mercury poisoning
dark teeth
impaired concentration
tremor
blindness
elemental mercury when ingested vs inhaled
ingested - only mildly toxic bc its not well absorbed by the GI tract
as a vapor - can penetrate the CNS and be toxic
Organic is absorbed more completely thru the GI tract!!!
