Trace Elements Flashcards
- is a crystalline silver-white ductile metal.
- is the most abundant metal in the earth’s crust (~8%).
- It is always found combined with other elements such as oxygen, silicon, and fluorine.
ALUMINUM
ALUMINUM can be combined with? (3)
oxygen, silicon, and fluorine
ALUMINUM: Approximately _____ to _____ inhaled and ______ to _____ of ingested aluminum are absorbed.
1.5% to 2%; 0.01% to 5%
The absorption efficiency of aluminum is dependent on (3)
- chemical form
- particle size (inhalation)
- concurrent dietary exposure to chelators such as citric acid
or lactic acid.
In plasma, aluminum is bound to ________ such as transferrin.
carrier proteins
In plasma, aluminum is bound to carrier proteins such as _______
transferrin
Aluminum binds to various ligands in the blood and
distributes to every organ, with highest concentrations ultimately found in (2)
- in bone (~50% of the body burden)
- lung tissues (~25% of the body burden)
Aluminum levels in lungs increase with ____.
age
______accounts for 95% of aluminum excretion with 2% eliminated in the ____.
Urine; bile
The mechanisms by which aluminum applies its toxicity are not well understood, though aluminum has been shown to interfere with a variety of?
Enzymatic processes
administration of aluminum to experimental animals is known to produce?
encephalopathy
Signs and symptoms of aluminum toxicity include (7)
- encephalopathy (stuttering, gait disturbance, myoclonic jerks, seizures, coma, abnormal EEG)
- osteomalacia or aplastic bone disease (painful spontaneous fractures, hypercalcemia, and tumorous calcinosis)
- proximal myopathy
- increased risk of infection
- microcytic anemia
- increased left ventricular mass
- decreased myocardial function
Aluminum toxicity occurs in people with _________ who are treated by dialysis with aluminum-contaminated solutions or oral agents that contain aluminum.
renal insufficiencies
The clinical manifestations of aluminum toxicity include (3)
- anemia
- bone disease
- progressive dementia with increased concentrations of
aluminum in the brain.
Prolonged intravenous feeding of preterm infants with
solutions containing aluminum is associated with?
impaired neurologic development
Aluminum is primarily measured using
ICP-MS or GFAAS
____ and _____ levels are useful in determining toxic exposures, monitoring exposure over time, and monitoring chelation therapy.
Urine and serum
is a ubiquitous element displaying both metallic and nonmetallic properties.
ARSENIC
For most people, ______ is the largest source of arsenic exposure (about 25 to 50 micrograms per day [μg/d]), with lower amounts coming from ______ and ______.
food; drinking water and air
The relation of clinical signs and symptoms to arsenic exposure depends on the (3)
- duration
- extent of the exposure to inorganic and methylated species of arsenic
- underlying clinical status of the patient
For acute arsenic exposure, the symptoms may include (6)
- gastrointestinal (nausea, emesis, abdominal pain, rice water diarrhea)
- bone marrow (pancytopenia, anemia, basophilic stippling)
- cardiovascular (EKG changes)
- central nervous system (encephalopathy, polyneuropathy)
- renal (renal insufficiency, renal failure)
- hepatic (hepatitis) systems
For chronic arsenic exposure, systems and symptoms
may include (4)
- dermatologic (Mees lines, hyperkeratosis, hyperpigmentation, alopecia)
- hepatic (cirrhosis, hepatomegaly)
- cardiovascular (hypertension, peripheral vascular disease)
- central nervous system (“socks and glove” neuropathy, tremor)
- malignancies (squamous cell skin, hepatocellular, bladder, lung, renal)
Chronic arsenic exposure has been shown to cause?
blackfoot disease (BFD)
ARSENIC: Doses of _______ g produce toxic symptoms. The lethal dose is reported to be between ______
0.01 to 0.05; 0.12 and 0.3
Immediate treatment of expected exposure consists of (2)
- lavage
- use of activated charcoal to reduce arsenic absorption
The most effective antidotes for arsenic poisoning are the
following chelating agents: (3)
- dimercaprol (a.k.a British anti-Lewisite, BAL)
- penicillamine
- succimer
In the year 2000, the U.S. FDA approved the use of arsenic trioxide for the treatment of _________, which is diagnosed in approximately 1,500 people in United States every year.
acute promyelocytic leukemia (APL)
Organic forms of arsenic such as ______ and _______ are commonly found in fish and seafood, are considered relatively nontoxic, and are cleared rapidly (1 to 2 days).
arsenocholine and arsenobetaine
Inorganic species of arsenic are _______ and occur naturally in rocks, soil, and groundwater.
highly toxic
Organic methylated arsenic compounds such as _____ and _____ are formed by hepatic metabolism of As(+3) and As(+5).
MMA and DMA
The __________ forms of arsenic are considered less toxic than As(+3) and As(+5); however, they are eliminated slowly (1 to 3 weeks).
methylated inorganic
Arsenic is primarily measured using (3)
- ICP-MS
- GFAAS
- HG-AAS.
is a soft, bluish-white metal, which is easily cut with a knife.
CADMIUM
Based on renal function (development of proteinuria), the reference dose for
cadmium in drinking water is _______ mg per kg per day (mg/kg/d), and the dose
for dietary exposure to cadmium is ______ mg/kg/d.
0.0005; 0.001
Absorption of cadmium is higher in ______ than in ______ due to differences in iron stores.
females than in males
The absorption of cadmium in cigarette smoke is
10% to 50%, and smokers of tobacco products have about _____ the cadmium abundance in their bodies as nonsmokers.
twice
For nonsmokers, the primary exposure
to cadmium is through ingested?
food
Ninety percent of ingested cadmium is excreted in the ______ due to the low absorbance of cadmium from the gut.
feces
CADMIUM: Toxicity is believed to be a result of ________ causing denaturation of the associated proteins, resulting in a loss of function.
protein-Cd adducts
Ingestion of high amounts of cadmium
may lead to a rapid onset with (3)
- severe nausea
- vomiting
- abdominal pain
_______ is a common presentation for chronic cadmium exposure, often resulting in slow-onset proteinuria.
Renal dysfunction
Acute effects of inhalation of fumes containing cadmium include respiratory distress due to (3)
- chemical pneumonitis
- edema
can cause death
Breathing of cadmium vapors can also result in (2)
- nasal epithelial damage
- lung damage
Cadmium exposure can affect the (5)
- liver
- bone
- immune
- blood
- nervous systems.
_______ can be used as a chelating agent in cadmium poisoning.
EDTA (ethylenediaminetetraacetic acid)
Cadmium is usually quantified by
- GFAAS
- ICP-MS
- CP-AES is also used
______ from the Greek word chroma (“color”), makes rubies red and emeralds green.
CHROMIUM (Cr)
Chromium exists in two main valency states:
- trivalent
- hexavalent
_____ is better absorbed and much more toxic than ______.
Cr(+6); Cr(+3)
Both _______ and ________ are involved in chromium absorption and transport.
transferrin and albumin
Transferrin binds the newly absorbed chromium at ______, while albumin acts as an _____ and ______ of chromium if the transferrin sites are saturated.
site B; acceptor and transporter
Transferrin binds the newly absorbed chromium at ______, while albumin acts as an _____ and ______ of chromium if the transferrin sites are saturated.
site B; acceptor and transporter
Other plasma proteins, including ____ and ____ and _____, bind chromium.
β- and γ-globulins and lipoproteins
_______ is an essential dietary element and plays a role in maintaining normal metabolism of glucose, fat, and cholesterol.
Cr(+3)
The estimated safe and adequate daily intake of chromium for adults is in the range of?
50 to 200 μg/d
Dietary chromium deficiency is relatively uncommon, and most cases occur in persons with specific clinical situations such as (3)
- total parenteral nutrition
- diabetes
- malnutrition
Chromium deficiency is characterized by (6)
- glucose intolerance
- glycosuria
- hypercholesterolemia
- decreased longevity
- decreased sperm counts
- impaired fertility
______ and ______ can result from contact with Cr(+6) salts.
Severe dermatitis and skin ulcers
Data suggest that a Cr(+3)–protein complex is responsible for the
allergic reaction
When inhaled, Cr(+6) is a respiratory tract irritant, resulting in (3)
- airway irritation
- airway obstruction
- possibly lung cancer
The target organ of inhaled chromium is the
- lung;
- the kidneys, liver, skin, and immune system may
also be affected.
Low-dose, chronic chromium exposure typically results only in
transient renal effects
Chromium may be determined by (3)
- GFAAS
- NAA
- ICP-MS
is a relatively soft yet tough metal with excellent electrical and heat conducting properties.
COPPER
Copper is an essential trace element found in four oxidation states
- Cu(0)
- Cu(+1)
- Cu(+2)
- Cu(+3)
is an important cofactor for several metalloenzymes and is critical for the reduction of iron in heme synthesis.
Copper
The copper content in the normal human adult is
50 to 120 mg
Copper is distributed through the body with the highest concentrations found in the
- liver
- brain
- heart
- kidneys
_____ copper accounts for about 10% of the total
copper in the body.
Hepatic
The amount of copper absorbed from the intestine is _____% to _____% of ingested copper.
50% to 80%
The average daily intake is approximately ______ or more of copper.
10 mg
The exact mechanisms by which copper is absorbed and transported by the intestine are unknown, but an _______ transport mechanism at low concentrations and _______ diffusion at high concentrations have been proposed.
active; passive
In the liver, copper is incorporated into ________ for distribution throughout the body.
ceruloplasmin
_____ is an α2-globulin, and each 132,000-molecular-weight molecule contains six atoms of copper.
ceruloplasmin
Copper deficiency is observed in
premature infants
copper absorption is impaired in
- severe diffuse diseases of small bowel
- lymph sarcoma
- scleroderma
Copper deficiency is related to
malnutrition, malabsorption,
chronic diarrhea, hyperalimentation, and prolonged feeding with low-copper,
total-milk diets.
Signs of copper deficiency include (4)
(1) neutropenia and hypochromic anemia in the early stages
(2) osteoporosis and various bone and joint abnormalities that reflect deficient copper-dependent cross-linking of bone collagen and connective tissue
(3) decreased pigmentation of the skin and general pallor
(4) in the later stages, possible neurologic abnormalities (hypotonia, apnea, psychomotor retardation).
Subclinical copper depletion contributes to an increased risk of
coronary heart disease
An extreme form of copper deficiency is seen in?
Menkes’ disease
Copper-induced emesis has a characteristic ______ color.
blue-green
______ disease is a genetically determined copper accumulation disease that usually presents between the ages of 6 and 40 years.
Wilson’s disease
Clinical findings include neurologic disorders, liver dysfunction, and Kayser-Fleischer rings (green-brown discoloration) in the cornea caused by copper deposition.
Wilson’s disease
Early diagnosis of Wilson’s disease is important because complications can be effectively prevented, and in some cases, the disease can be halted with use of (2)
zinc acetate or chelation therapy
Copper is measured by (4)
- AAS
- ICP-MS
- ICP-AES
- ASV
is fourth most abundant element in the earth’s crust and the most abundant transition metal.
Iron (Fe)
Of the 3 to 5 g of iron in the body, approximately ____ to _____ g of iron is in hemoglobin, mostly in RBCs and red cell precursors.
2 to 2.5 g
Iron is also stored as _____ and ______, primarily in the bone marrow, spleen, and liver.
ferritin and hemosiderin
Increased blood loss, decreased dietary iron intake, or decreased release from ferritin may result in?
iron deficiency
Iron overload states are collectively referred to as _________, whether or not tissue damage is present.
hemochromatosis (HH)
______ has been used to specifically designate a condition of iron overload as demonstrated by an increased serum iron and total iron-binding capacity (TIBC) or transferrin, in the absence of demonstrable tissue damage.
Hemosiderosis
Measurement of serum iron concentration refers specifically to the Fe+3 bound to transferrin and not to the iron circulating as free hemoglobin in serum.
Total Iron Content (Serum Iron)
refers to the theoretical amount of iron that could be bound if transferrin and other minor iron-binding proteins present in the serum or plasma sample
were saturated.
Total Iron-Binding Capacity
is the ratio of serum iron to TIBC.
Percent Saturation
Transferrin is measured by immunochemical methods such as
nephelometry
Transferrin is increased in ________ and decreased in ______ and ______.
iron deficiency; iron overload and HH
Transferrin may also be decreased in _______ and _______.
chronic infections and malignancies
Ferritin is decreased in ________ and increased in _______ and _______
iron deficiency anemia; iron overload and HH.
_________ is soft, bluish white, highly malleable, and ductile. It is a poor conductor of electricity and heat and is resistant to corrosion.
LEAD
Exposure to lead is primarily ________ or ________.
respiratory or gastrointestinal.
Certain substances, such as iron, calcium, magnesium, alcohol, and fat, may ________ lead absorption, while low dietary zinc, ascorbic acid, and citric acid can _______ the absorption
of lead.
weaken; enhance
Lead exposure primarily arises in two settings:
- childhood exposure, usually
through paint chips - adult occupational exposure in the smelting, mining, ammunitions, soldering, plumbing, ceramic glazing, and construction industries.
LEAD: The most common specimen type is whole venous blood, the result of which is commonly referred to as the?
blood lead level or BLL
LEAD: ________ is a preferred method of analysis, although ICP-AES and GFAAS are also used.
ICP-MS
also called quicksilver, is a heavy, silvery metal. Along with bromine, ________ is one of only two elements that are liquid at room temperature and pressure.
mercury
There are three naturally occurring oxidation states of mercury:
Hg(0), Hg(+1), and Hg(+2).
MRECURY: Routes of exposure include (5)
(1) inhalation, primarily as elemental mercury vapor but occasionally as dimethyl mercury;
(2) ingestion of HgCl2 and mercury-containing foods such as predatory fish species;
(3) cutaneous absorption of methyl mercury through the skin and even through latex gloves;
(4) injection of relatively inert liquid mercury and mercury-containing tattoo pigments;
(5) dental amalgams
Low levels of manganese have been associated with
- epilepsy
- hip abnormalities
- joint disease
- congenital malformation
- heart and bone problems
- stunted growth in children
Chronic manganese toxicity resembles _________ with akinesia, rigidity, tremors, and masklike faces.
Parkinson’s disease
_______ toxicity causes nausea, vomiting, headache, disorientation, memory loss, anxiety, and compulsive laughing or crying.
Manganese toxicity
Manganese is measured by (2)
ICP-MS and GFAAS
is a hard, silvery white metal occurring naturally as
molybdenite, wulfenite, and powelite.
MOLYBDENUM
______ can cross the placental barrier, and high levels of molybdenum in the diet of the mother can increase the molybdenum in the liver of the neonate.
Molybdenum
Molybdenum is vital to human health through its inclusion in at least three enzymes:
xanthine oxidase, aldehyde oxidase, and sulfite oxidase.
The active site of these enzymes binds molybdenum in the form of a cofactor _______
“molybdopterin.”
