Mercury Flashcards
what can mercury do to the brain
demyelination
what are the 3 forms of mercury
elemental, inorganic and organic
where is elemental mercury often found
in thermometers
what state is elemental mercury at room temperature
liquid
what is inorganic mercury
mercury bound to other elements
what is often mercury combined with in inorganic mercury
chloride
what are 2 types of organic mercury
methylmercury and dimethylmercury
where is methylmercury often found
in fish
what is the deal with dimethylmercury
a few millilitres can kill and it easily passes through the skin
what is the deal with mercury vapour
it is readily absorbed via the lungs so it is extremely hazardous
does mercury vapour absorb in the lungs easily? what %
yes, 80%
what happens if you swallow elemental mercury liquid
non toxic actually
what happens once you inhale elemental mercury
catalase in RBC convert it into inorganic or divalent form
how does elemental mercury accumulate in the CNS
because it is ionized so then its trapped once it enters the CNS
where does mercury get accumulated in the body
CNS
how does elemental mercury stay in the CNS (why is it trapped)
because it is ionized
what are the symptoms of ionized elemental mercury accumulation similar to
symptoms to inorganic poisoning
how is inorganic mercury often found
as metallic mercury (Hg) or as salts: Hg+ or Hg2+ often as Hg- chloride or sulfide
what is inorganic mercury often used for
batteries, plastics, fungicides
what are 2 bad things about inorganic mercury (general)
toxic, corrosive
what is the primary route of inorganic mercury entry
oral
what is oral entry of inorganic mercury absorption
poor, 10%
what is cinnabar
mercury sulfide
besides oral, how else can inorganic mercury enter the body
through skin
where does inorganic mercury accumulate + how
renal tubules via OATs
how does inorganic mercury accumulate in the renal tubules
via OATs
what is CNS penetration of inorganic mercury like (2)
very little because of low lipophilicity
-but slow elimination & chronic exposure can result in toxicity
what are 3 forms of organic mercury
aryl (ring), short and long chain alkyl compounds
how is organic mercury (like methylmercury) easily absorbed + %
easily through GI (50-90%)
what happens once organic mercury enters via GI (where does it go)
it is distributed to most organs, can pass BBB and placenta
can organic mercury pass BBB
yes
can organic mercury cross placenta
yeah :(
what happens once organic mercury is absorbed (what does it turn into)
inorganic form
what is the formula for methylmercury
CH3Hg+
what is a way that methylmercury can cause damage
it has high affinity for SH groups so it replaces the hydrogen (damage proteins, enzymes)
what is the most common way to be exposed to methylmercury
seafood
how much dimethylmercury can kill you
a few millilitres
what are acutes symptoms of elemental mercury as vapour toxicirt
bronchial irritation, pneumonites, can be fatal
-mercury vapor triad too
what is the mercury vapor triad
tremors, gingivitis and erethism
what is erethism
memory loss, excitability, insomnia, depression, shyness
what are 4 acute symptoms for inorganic hg toxicity
abdominal pain, nausea, vomiting, diarrhea
what happens to kidneys with inorganic hg toxicity (2)
acute binding to thiols, epithelial cell necrosis of proximal tubule
what happens with chronic low dose of inorganic mercury
immunologic glomerular disease, proteinurea (high MW)
what is the main type of toxicity with organic hg
neurotoxicity
cortex and cerebellum
where in the brain does organic hg effect the most
cortex and cerebellum
what are some bodily symptoms of organic hg toxicity
paresthesia, ataxia, weakness, coma, death
what is parathesia
numbness and tingling around mouth and lips (peripheral nerve damage)
what happens to the brain with organic hg toxicity (3)
edema, grey matter destruction, atrophy
list the following symptoms in order of least to most mercury required
death ataxia deafness paresthesia dysarthria (motor speech disorder)
paresthesia ataxia dysarthria (motor speech disorder) deafness death
what 3 major mechanisms are thought to cause methylmercury cytotoxicity
- increased inracellular Ca2+
- covalent modification of sulfhydryl groups
- increase oxidative stress
how does methylmercury cytotoxicity cause increased intracellular Ca++
release from intracellular stores via muscarinic receptor activation on ER followed by increase entry thru membrane bound channels
what happens to SH groups with methylmercury cytotoxicity
they become covalently modified
how does oxidative stress happen with methylmercury cytotoxicity
increase ROS or decrease GSH (not via fenton)
how does methylmercury cytotoxicity cause fenton reaction
it doesntttttt
what is the type of cell death that happens with methylmercury cytotoxicity and why
it depends on the level of exposure
what are 3 drugs that are used for Hg poisoning
DMPS, BAL and penicillamine
what is DMPS
chelator
which type of hg poisoning is DMPS good for
inorganic
what administration is DMPS
oral
what can DMPS do (2)
- penetrate into kidney cells to remove it
- remove mercury in some tissues (not brain)
can DMPS remove mercury from brain
no, but it might decrease neurotoxicity in chronic exposure
what is BAL used for (what type of Hg poisoning)
inorganic but not organic
what can BAL do
remove inorganic from kidneys
what is bad about BAL
injections are painful
what is penicillamine used for + how
chelator for methylmercury and mercury vapour
what happens to blood mercury levels with DMPS
decrease
what happens to urine mercury levels with DMPS
increase initially
