CHAPT 57: HEAVY METALS Flashcards
Pure Baby Katzung Content
The
toxicity profiles of metals differ, but most of their effects appear
to result from interaction with _______ groups of enzymesand regulatory proteins.
sulfhydryl
organic compounds with 2 or more electronegative groups that form stable bonds with cationic metal atoms.
Chelators
Chelators function as chemical _________ (agonist or antagonist)
antagonists
used as antidotes in the treatment of heavy metal poisoning
Chelators
Heavy metal that serves no useful purpose in the body and can damage the hematopoietic tissues, liver, nervous system, kidneys, gastrointestinal tract, and reproductive system
Lead
a major environmental hazard because it is present in the air and water throughout the world
Lead
The primary signs of this syndrome are acute abdominal colic and central nervous system (CNS) changes, including, particularly in children, acute encephalopathy.
Acute lead poisoning
also known as plumbism
Chronic lead poisoning
Signs include peripheral neuropathy (wrist-drop is characteristic), anorexia, anemia, tremor, weight loss, and gastrointestinal symptoms.
Chronic lead poisoning
Chronic lead poisoning is treated via chelation therapy with ____ ________
oral succimer
presents as growth retardation, neurocognitive deficits, and developmental delay in children
Chronic lead poisoning
High dietary
________ impedes lead absorption.
calcium
poisoning due to tetraethyl lead or tetramethyl lead contained in “antiknock” gasoline additives
Organic lead poisoning
widely used in industrial processes and is also present in certain soils and released during the burning of coal
Arsenic
results in severe gastrointestinal discomfort, vomiting, “rice-water” stools, and capillary damage with dehydration and shock
Acute arsenic poisoning
In acute arsenic poisoning, a ______,_______ odor may be detected in the breath and the stools.
sweet; garlicky
Acute arsenic poisoning is treated via chelation therapy with ________
dimercaprol
causes skin changes, hair loss, bone marrow depression and anemia, and chronic nausea and gastrointestinal disturbances
Chronic arsenic poisoning
an occupational hazard
formed during the refinement and processing of certain metals and
is used in the semiconductor industry
Arsine gas
causes a unique form of toxicity characterized by massive hemolysis
Arsine
used as seed dressings and fungicides
Organic mercury
used in materials in dental laboratories and in the manufacture of wood preservatives, insecticides, and batteries
Inorganic mercury
usually occurs through inhalation of inorganic elemental mercury
Acute mercury poisoning
Chronic mercury intoxication has
been treated with _______ and _______, but their efficacy has not
been established.
succimer; unithiol
_________ may redistribute mercury to the CNS and should not be used in chronic exposure to elemental mercury.
Dimercaprol
first recognized in connection with
an epidemic of neurologic and psychiatric disease in the village of Minamata, Japan
Organic mercury poisoning
occurs frequently in small children
Acute iron poisoning
the chelating agent
of choice for Iron poisioning
Deferoxamine
Chronic excessive intake of iron can lead to
hemosiderosis or hemochromatosis
is a bidentate chelator; that is, a chelator that forms 2 bonds with the metal ion, preventing the metal’s binding to tissue proteins and permitting its rapid excretion
Dimercaprol (BAL)
acute arsenic and mercury poisoning and, in combination with EDTA, for lead poisoning.
Dimercaprol
Dimercaprol is a/an _____ liquid that must be given parenterally.
oily
Long-term use of Dimercaprol is associated with __________ and
increased prothrombin time.
thrombocytopenia
is a water-soluble
bidentate congener of dimercaprol
Succimer (DMSA)
used for the oral treatment of lead toxicity in children and adults.
Succimer
Succimer is also
effective in ______ and _________ poisoning, if given within a few
hours of exposure.
arsenic; mercury
A water-soluble derivative of dimercaprol
Unithiol
MOA of Unithiol
Orally or Intravenously
causes a low incidence of dermatological reactions, usually mild
Unithiol
a derivative of penicillin, another bidentate chelator
Penicillamine
The major uses of penicillamine
treatment of copper poisoning and Wilson’s disease
an efficient polydentate chelator of many divalent cations, including calcium, and trivalent cations
Ethylenediaminetetraacetic Acid (EDTA; edetate)
The primary use of EDTA is in the treatment of
lead poisoning
To prevent dangerous hypocalcemia, EDTA is given as the _______ ________ salt.
calcium disodium
The most important adverse effect of EDTA is nephrotoxicity, including
renal tubular necrosis
a polydentate bacterial product with an extremely
high and selective affinity for iron and a much lower affinity for aluminum
Deferoxamine
competes poorly for heme iron in hemoglobin and cytochromes
Deferoxamine
a newer tridentate
chelator with selectively high affinity for iron
Deferasirox
used parenterally in the treatment of acute iron intoxication and in the treatment of iron overload caused by blood transfusion
Deferoxamine
an oral drug approved for treatment of iron overload
Deferasirox
Rapid intravenous administration of deferoxamine can
cause _______ release
histamine
a hydrated crystalline compound in which Fe2+ and Fe3+ atoms are coordinated with cyanide groups in a cubic
lattice structure.
Prussian blue
Prussian blue is approved for the treatment of contamination with radioactive ______ and intoxication
with _______ salts.
cesium; thallium
