Trace Elements and Anemia Quiz

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Questions and Answers

What is the best definitive test for human trace mineral element deficiency?

Urine specimen analysis

Clinical response to controlled supplementation (correct)

Hair analysis

Blood serum assay

Which method employs flame for trace and toxic metal analysis?

Graphite Furnace Atomic Absorption Spectrometry

X-Ray Fluorescence Spectrometry

Inductively Coupled Plasma Mass Spectrometry

Flame Atomic Absorption Spectrometry (correct)

Which of the following is NOT a cause of trace element deficiency?

Excess soil contamination (correct)

Increased catabolism

Nutritional deficiency

Inadequate supplementation due to Total Parenteral Nutrition

What is essential for ensuring analytic accuracy in trace element analysis?

Employment of ultra-pure reagents and clean room techniques Signup and view all the answers

How does zinc affect copper levels in the body?

Interferes with copper absorption Signup and view all the answers

Which of the following describes essential trace elements?

Elements whose deficiency impairs biochemical reactions Signup and view all the answers

Which trace element is primarily known for its role in electron and oxygen transport?

Iron Signup and view all the answers

What characterizes nonessential trace elements?

They are of medical interest mainly due to their toxicity Signup and view all the answers

Which trace elements influence vitamin or hormonal activity?

Zinc, Iodine, Chromium, Selenium Signup and view all the answers

Which method is NOT typically used for laboratory evaluation of aluminum?

NMR Spectroscopy Signup and view all the answers

What is the primary mode of exposure to aluminum?

Inhalation and parenteral injection Signup and view all the answers

Which statement about the excretion of aluminum is accurate?

95% of aluminum is excreted in urine Signup and view all the answers

Which population group has the highest risk for iron deficiency anemia?

Pregnant women Signup and view all the answers

Which of the following is NOT a feature associated with iron deficiency anemia (IDA)?

Hemosiderosis Signup and view all the answers

What does the Total Iron Binding Capacity (TIBC) measure?

Iron that could be bound by transferrin Signup and view all the answers

Which of the following statements regarding iron toxicity is correct?

Hemosiderosis does not cause demonstrable tissue damage. Signup and view all the answers

What is the preferred time to collect a sample for measuring Total Iron Content?

Early morning Signup and view all the answers

How is excess iron removed during the measurement of TIBC?

Using magnesium carbonate Signup and view all the answers

What percentage of the global population is affected by iron deficiency?

15% Signup and view all the answers

Which of the following factors does NOT contribute to iron deficiency?

Increased iron storage Signup and view all the answers

What laboratory evaluation method is used to assess iron metabolism disorders?

Hemoglobin and hematocrit Signup and view all the answers

What is the preferred specimen for detecting lead poisoning?

Whole venous blood Signup and view all the answers

Which form of mercury is considered very toxic and selectively accumulates in brain tissue?

Methyl mercury Signup and view all the answers

Which route of mercury exposure involves inhalation of mercury vapors?

Inhalation Signup and view all the answers

What is the essential trace element that functions in several oxidase enzymes?

Molybdenum Signup and view all the answers

Which of the following substances is used in dental amalgams?

Elemental mercury Signup and view all the answers

Which food sources are particularly high in molybdenum?

Grains, nuts, and legumes Signup and view all the answers

What role does selenium play in the body?

Defense against oxidative stress Signup and view all the answers

What is a disease associated with selenium deficiency that primarily affects children and young women in specific regions of China?

Keshan disease Signup and view all the answers

Which of these options describes the most harmful form of mercury exposure?

Elemental mercury vapor inhalation Signup and view all the answers

What are common symptoms of zinc deficiency observed in acrodermatitis enteropathica?

Alopecia and hyperpigmented skin lesions Signup and view all the answers

How does selenium's perception in human health change over the decades?

Toxic, then carcinogenic, then essential, then anticarcinogenic Signup and view all the answers

Which analytical methodology is essential for assessing trace mineral status?

Atomic absorption spectroscopy Signup and view all the answers

Which test methodology is useful for monitoring chelation therapy for lead exposure?

Urine test Signup and view all the answers

What condition can arise from chronic oral zinc supplementation due to its interference with copper absorption?

Copper deficiency Signup and view all the answers

What is the most common symptom of selenium toxicity?

Hair loss Signup and view all the answers

What major role does zinc play in the body?

Catalyzing reactions involving more than 300 enzymes Signup and view all the answers

In diagnosing trace mineral deficiencies, what is essential for accurate assessment?

Careful inspection for symptoms and thorough understanding of causes Signup and view all the answers

What are the potential effects of inhaling zinc oxide fumes?

Metal fume fever Signup and view all the answers

What trace element-dependent enzyme activity measurement is helpful in determining trace element status?

Activity of a trace element-dependent enzyme Signup and view all the answers

What chronic condition is associated with low selenium levels and is characterized by osteoarthritis?

Kashin-Beck disease Signup and view all the answers

Study Notes

Trace Elements

Also known as micronutrients
Naturally occurring, homogeneous, inorganic substance
Humans require these in amounts less than 100 mg/day
Have specific in vivo metabolic functions
Cannot be effectively performed by other elements

Categories of Elements

Classified based on their biological effects, deficiency diseases and toxicity from overdose
Essential elements: deficiency impairs biochemical reactions that are corrected by replacement of the element
Possibly essential elements
Nonessential elements: primarily of medical interest because of their toxicity. Mostly metals except selenium and halogens (fluoride and iodine)

Roles of Trace Elements

Structural signal transduction and special catalytic properties (Zn, Cu, Mg)
Some trace elements are components of metalloenzymes and metalloproteins, acting as cofactors (Fe, Se, Mo, Cr)
Provides electron and oxygen transport (Cu)
Maintenance of macromolecule conformation (Zn, Cu)
Influences vitamin or hormonal activity (Zn, Cr, Se)

Possibly Essential Elements in Animals

Bromine
Cadmium
Lead
Strontium
Tin

Not Essential Elements

Aluminum
Antimony
Bismuth
Germanium
Mercury
Silver
Thallium
Titanium

Aluminum

Crystalline silver-white ductile metal
Most abundant metal in the Earth's crust
Good conductor of heat and electricity
Found in consumer products such as antacids, astringents, buffered aspirin, food additives, cosmetics, and antiperspirants
Non-essential

Aluminum - Mode of Exposure and Concentration in Organs

Mode of exposure: orally, through inhalation, and parenterally (injection)
In plasma, aluminum is bound to carrier proteins such as transferrin
Concentration in organs:
- Bone: 50%
- Lung tissues: 25%
- Excretion: urine (95%), bile (2%)

Lab Evaluation

Specimens: urine, serum
Methodologies: ICP-MS, GFAAS

ICP-MS

Inductively coupled plasma mass spectrometry
Plasma, interface, quadrupole, carrier gas, spray chamber, sample, ion lens, detector, nebulizer

GFAAS

Graphite furnace atomic absorption spectroscopy
Sample injection port, atomization chamber, graphite furnace, monochromator, detector, light source

Arsenic

Nonessential
Food is the largest source
Lower amounts come from drinking water and air
Commonly found in fish and seafood
Used as a wood preservative

Iron

Ferrous (Fe2+) and ferric (Fe3+) irons
Fourth most abundant element in the earth's crust and the most abundant transition metal
No excretory system for excess iron
Primary means of iron regulation: absorption of iron from the intestine

Iron Metabolism

Only the Fe2+ form can be absorbed by the intestine
Fe3+ is first reduced to Fe2+
Present in intestinal epithelial cells
Stored as ferritin or oxidized to Fe3+
Exported on the basolateral side and bound to apotransferrin for distribution in the body
Release of Fe3+ from intestinal cells is mediated by ferroportin and regulated by hepcidin

Iron - Amount in the body

3-5 g of iron in the body
Approximately 2-2.5 g is in hemoglobin, mostly in RBC and its precursors
Moderate amount of iron (130mg) is found in myoglobin
8mg is found in enzymes like peroxidases, cytochromes, and many of Kreb cycle's enzymes
Stored as ferritin or hemosiderin in bone marrow, spleen or liver
Only 3-5 mg of iron is found in plasma bound to transferrin, albumin, and free hemoglobin

Iron Deficiency

Affects 15% of the worldwide population
At risk: pregnant women, young children, adolescents, women of reproductive age
Caused by increased blood loss, decreased intake, or decreased release from ferritin
IDA (Iron Deficiency Anemia): most common anemia in the planet

Other Features of IDA

Pagophagia (craving ice)
Pica (craving of non-food substances: dirt, clay, laundry starch)
Glossitis (smooth tongue)
Restless legs
Angular stomatitis (cracking of corners of mouth)
Koilonychia (thin, brittle, spoon-shaped fingernails)

Iron Toxicity

Hemochromatosis: collective term for iron overload with or without tissue damage
Associated hereditary hemochromatosis (HH): leading to abnormally high iron absorption; affects liver function and often leads to hyperpigmentation of the skin
Hemosiderosis: iron overload without demonstrable tissue damage

Lab Evaluation (Iron)

Disorders of iron metabolism are evaluated by
- Hematocrit & hemoglobin
- RBC count & RBC indices
- Total iron level
- Percent saturation
- Transferrin
- Ferritin
- TIBC (Total iron-binding capacity)

Total Iron Content (Serum Iron)

Refers specifically to the Fe3+ bound to transferrin
Heparinized plasma may be used
Oxalate, citrate, EDTA binds iron and are unacceptable
Early morning sample is preferred due to diurnal variation

Total Iron Binding Capacity (TIBC)

Refers to the amount of iron that could be bound by saturating transferrin and other minor iron-binding proteins present in the serum or plasma sample
Direct measure of the available transferrin receptors
All TIBC methods require addition of excess iron to saturate transferrin
Excess iron is removed by adding magnesium carbonate to measure the bound iron
IDA have high TIBC; other anemias have low TIBC (non-iron deficiency)

Percent Saturation

Also known as transferrin saturation
An index of iron storage
Ratio of serum iron to TIBC
Normal values are around 1/3
IDA values significantly reduce to 1/5 or less

Lab Methodologies (various)

COLORIMETRY: Uses HCl and ferrozine → blue color; iron dyes: bathophenanthroline, tripyridyltriazine
ANODIC STRIPPING VOLTAMMETRY: First step in serum iron quantitation is separation from transferrin.
Serum iron is falsely elevated by hemolysis and affected by diurnal variation. Iron is highest in the morning
LAB METHODOLOGIES, Specimen: Whole venous blood (preferred over serum or plasma due to lead being mostly in red blood cells) Urine: useful for recent exposure or monitoring of chelation therapy
Radiographic methods: measure amount of lead in bones
Other methods: plasma aminolevulinic acid, whole blood Zinc protoporphyrin free erythrocyte protoporphyrin.

Lead

Plays no known role in normal human physiology
Lead-based household paints were banned in the US in 1972
Recent recalls of toys from China
Exposure primarily gastrointestinal and respiratory
99% of absorbed lead is taken up by erythrocytes, interfering with heme synthesis

Lead Poisoning

Lead blocks the action of:
- 6-aminolevulinic acid (ALA) synthetase
- 6-ALA dehydratase (ALAD)
- Coproporphyrinogen decarboxylase
- Ferrochelatase
This produces anemia

Lead Poisoning Additional Aspects

In addition, lead blocks two other enzymes: pyrimidine-5'-nucleotidase and Na-K dependent ATPase. This leads to diminished energy supply for red blood cells and decreased cell membrane integrity.
Because pyrimidine-5'-nucleotidase is needed to remove clumped RNA, lead inhibition results in RNA clumping observed as basophilic stippling of red blood cells.

Mercury

Also called quicksilver
Three naturally occurring oxidation states: Hg(0), Hg+, Hg2+
Organic mercury: Hg2+ attached to carbon atoms
Used in dental amalgams, electronic switches, germicides, fungicides, fluorescent light bulbs, OTC drugs, laxatives, diaper-rash ointments, eye drops, nasal sprays, and eye cosmetics (especially mascara).

Mercury - Routes of Exposure

Inhalation (primarily elemental mercury vapor)
Ingestion (HgCl2 and mercury-containing foods such as predatory fishes)
Cutaneous absorption (methyl mercury through skin and even through latex gloves)
Injection (liquid mercury and mercury-containing tattoo pigments)

Forms of Mercury

Elemental mercury vapors: highly absorbed and toxic; harmful effects on nervous, digestive and immune systems
Liquid elemental mercury: poorly absorbed and relatively nontoxic
Inorganic salts: affects the skin, eyes, GIT and kidneys
Methyl mercury: very toxic, highly selective for lipid-rich medium such as brain

Molybdenum

An essential trace element
Component of xanthine oxidase, aldehyde oxidase, and sulfite oxidase
Binds molybdenum in the form of a cofactor called molybdopterin
Grains, nuts, and legumes (peas, lentils, beans) are good sources
Can cross the placental barrier and increase intake, increasing levels in the mother's liver

Selenium

Considered a toxic element (1930s), carcinogen (1940s), essential element (1950s) and anticarcinogen (1960s)
Constituent of glutathione peroxidase, associated with vitamin E functions that are important in defense against oxidative stress
Involved in the metabolism of thyroid hormones: deiodinase, thioredoxin reductase

Selenium - Deficiency & Toxicity

Deficiency associated with cardiomyopathy, skeletal muscle weakness and osteoarthritis
- Keshan disease: endemic cardiomyopathy affecting mostly children and child-bearing age in some areas of China
- Kashin-Beck disease: endemic osteoarthritis occurring during adolescent and preadolescent years in certain parts of China and other regions
Toxicity: hair loss, garlic breath, irritability, mild nerve damage, nail damage

Zinc

Second only to iron in importance as an essential trace element
The most common catalytic metal ion in the cytoplasm of cells
Main biochemical role seen in its influence on the activity of more than 300 enzymes (oxidoreductases, transferases, lyases, isomerases, and lipases)

Genetic Zinc Deficiency

Acrodermatitis enteropathica: rare autosomal recessive disorder with impaired intestinal absorption and transport of zinc
Symptoms: hyperpigmented skin lesions, pustular and bullous dermatitis, alopecia, growth retardation, diarrhea, secondary infection, irritability, lethargy, and depression

Zinc Toxicity

Inhalation of zinc oxide fumes is the most common cause of metal fume fever
Chronic oral zinc supplementation interferes with copper absorption and may cause copper deficiency.

Analytical Considerations (Trace Elements)

Assessment of trace mineral status difficult, requiring specialized analytical instruments (AAS, AES)
Serum measurements complicated by associated diseases that affect circulating binding proteins (e.g., albumin)
Diagnosis dependent on high degree of suspicion, careful inspection of signs and symptoms, understanding of predisposing causes, and resolution of symptoms with therapeutic trial.

Analytical Considerations - Specimen Collection

Trace elements must be carefully analyzed using clean room techniques and ultra-pure reagents (e.g., type I water)
Reference materials and strict quality control are requisite in each assay run to ensure analytic accuracy.
Special collection and handling necessary; ubiquitous biological materials (needles, syringes, stoppers) can contaminate samples.
Remedy: use trace element-free syringes, evacuated tubes with fitted siliconized needles, acid-washed glassware, use standard reference materials

Causes of Deficiency

Decreased intake (nutritional deficiency)
Total parenteral nutrition (inadequate supplementation)
Increased utilization (increased catabolism)
Interactions between trace elements (e.g., zinc, copper) or other nutrients (zinc, vitamin C)
Increased excretion
Disease states (insufficient intestinal absorption: acquired; malabsorption, intestinal resection; genetic; mutation resulting in lack of protein needed to absorb the element)

Lab Methodologies

Atomic Absorption Spectrometry (AAS):
- Most commonly used for trace and toxic metal analysis
- Flame AAS: uses flame; used in measurement of copper, iron, zinc, LOQ (limit of quantification) - parts per million (mg/L)
- GFAAS: uses graphite furnace; used in the measurement of selenium, cadmium, lead
Atomic Emission Spectroscopy (AES):
- Uses flame or inductively coupled plasma
- Liquid sample converted into aerosol, delivered to source for atom excitation
- Isolates specific wavelengths
- Measures radiation intensity, photographic film (obsolete) replaced by photomultipliers and array-based detector systems.

Elemental Speciation

Toxicity of the elements depends on their chemical form
e.g., Arsenic:
- Arsenobetaine: nontoxic form
- Methylated forms: intermediate in toxicity
- Inorganic arsenic (As(V), As(III)): highly toxic
Hyphenated techniques: allow determination of elemental species
Combination of two or more complementary analytical techniques.

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Description

Test your knowledge on trace minerals and their role in human health with this quiz. Covering topics from deficiencies to methods of analysis, this quiz will challenge your understanding of essential and nonessential trace elements. Perfect for students in nutrition or biomedical fields.