Trace Elements Flashcards
List the essential trace elements
Iron Zinc Copper Manganese Chromium Selenium
List the non-essential trace elements
Arsenic
Mercury
Lead
Cadmium
What tube is used for blood collection?
Royal blue top
2 main methods of testing for trace elements
Atomic Absorption
Atomic Emission
How does atomic absorption work?
Quantitates elements through absorption of optical radiation by free atoms in a gas phase.
Spectra of atoms is specific to absorbing elements
How does atomic emission work?
Liquid sample with element is concerted into an aerosol and delivered to a source where it receives energy & emits radiation.
Radiation measured and correlated to concentration of analyte
Non-essential elements are…
not needed for biological functions;
of medical interest for their toxic properties
Essential elements…
have function in the body. Need to determine both deficiency and toxicity.
Where does arsenic come from?
Natural substance in soil
Burning of fossil fuels
Agriculture uses
Contaminated ground water
How are people exposed to arsenic?
Food, water, inhalation
Forms of Arsenic
Inorganic (high toxicity)
Methylated (mild toxicity)
Organic (non-toxic)
Preferred sample for Arsenic testing
Urine
blood has short half-life; hair and nails used for chronic/long-term exposure
Symptoms of arsenic toxicity
GI symptoms
Bone marrow (pancytopenia, basophilic stippling)
CV, CNS, renal & hepatic problems
skin manifestation of arsenic toxicity
lesions on hands, soles of feet
Cadmium is absorbed primarily via ____
food
Samples for cadmium testing
random/24 hour urine, blood
Cadmium absorption higher in ____
females (related to iron stores)
____ have 2x the cadmium as _____ (hint: lifestyle)
smokers; non-smokers
Blood samples can be used to test for cadmium because ________
Cd binds to RBCs. Tested like HbA1C
Cadmium toxicity causes:
- Cancer
- Hindered brain development in kids
- Respiratory distress
- renal dysfunction
- also affects liver, bone, immune system and nervous system
Mercury exposure occurs by:
Inhalation, ingestion, injection
Toxicity occurs when mercury reacts with _________; binding _____ in proteins
sulfhydral groups;
cysteine
Forms of mercury
- Liquid environmental (non-toxic, but toxic in vapor form)
- Inorganic (non-toxic)
- Organic (toxic)
Organic mercury is toxic due to…
Being highly selective for lipid-rich neurons
S/S of mercury toxicity
Inhaled vapor: affects nervous, digestive & immune systems
Inorganic exposure: skin, eyes, GI symptoms, kidneys
Lead is primarily absorbed by:
GI and respiratory tracts
Lead used to be used in:
Paints, gasoline
Once absorbed, lead distributed to:
Soft tissues of liver, kidney, brain
Sample(s) for lead testing
Venous whole blood most common.
Hair and nails also used.
S/S of lead toxicity
CNS: clumsy/abnormal gait, HA, seizures
Neuropathy
Anemia
Lead causes _____ of RBCs
basophilic stippling
Copper in body commonly found in ____
Metalloenzymes
Wilson’s disease is copper ______
toxicity
Alpha-2 globulin that contains copper
Ceruloplasmin
What is Ceruloplasmin important in regulating?
Ionic states of Iron. Allows Fe to enter transferrin without forming toxic products.
What is Menkes Disease?
Fatally progressive brain disease caused by Copper deficiency.
What are common features of Menkes disease?
Kinky-steely hair, growth retardation.
Appears at 3 months, death at 5 years.
Disease of copper toxicity
Wilson’s disease
Wilson’s disease is a genetic condition resulting in ________ of copper
accumulation;
Copper gets deposited in tissues
Wilson’s disease causes:
accumulation of copper in tissues;
neurological and liver dysfunction;
Kayser-Fleischer rings
What are Kayser-Fleischer rings?
What condition are they seen in?
Green-brown discoloration of cornea;
Wilson’s disease
In Wilson’s Disease, serum copper levels are _______ and urinary copper is ____
Decreased; increased.
Treatment of Wilson’s disease
Penicillamine (binds copper)
Symptom’s of Wilson’s Disease:
Acute hemolytic anemia
Neurologic syndrome
Renal dysfunction (decreased GFR)
In Menkes, serum copper is _____ and urine copper is _______
decreased; increased
Zinc deficiency caused by:
old age, lactation, alcoholism, malnutrition
Zinc excess caused by:
Exposure to zinc fumes (zinc fume fever)
Zinc toxicity causes:
Pneumonia
Fever, cough, leg pain, chest pain, vomiting
Ionic states of iron:
Fe2: ferrous
Fe3: ferric
Storage forms of iron
Ferritin
Hemosiderin
Transport form of iron
Transferrin
Normal body iron content:
4-5 grams, more than half in RBCs
T/F: Iron homeostasis is controlled by excretion rather than absorption
False.
Body rigorously conserves Fe- very little is lost. Regulates by absorption.
Dietary iron ingested in _____ form
Ferric (Fe3)
After iron is ingested, it must be ______ in stomach and then ______ in intestine.
reduced to Fe2;
oxidized to Fe3
_______ form of iron stored as ferritin
Ferric (Fe3)
Ferritin = _______ + _________
Ferric ion + apoferritin
If apoferritin quantities are insufficient to store iron, iron gets deposited into tissues as ________
hemosiderin
Usually only ____ of transferrin binding sites are used
1/3
T/F: Ferritin levels generally reflect total Fe stores in body
True (per Mitch)
Total iron refers to:
Fe3 bound to transferrin, not Fe circulating as free Hgb
Sample requirements for iron studies
serum or heparinized plasma
not EDTA or other anticoagulants
Why is EDTA not used to test for iron?
Binds iron. Only heparinized plasma should be used.
Iron in serum/plasma measured by:
Spectrophotometric methods
Steps for iron quantitation:
- Release Fe3 from protein via acidification
- Reduce Fe3 to Fe2 by ascorbic acid/reducing agent
- Complex Fe2 with color reagent and measure
TIBC refers to:
amount of iron that could be bound by saturating transferrin and other binding proteins
Ferritin has ______ relationship with transferrin
Inverse
% iron saturation =
Serum Fe / TIBC * 100
Transferrin is a ______ acute phase protein
negative
Transferrin increased in ______
Iron deficiency
Transferrin decreased in ________
Iron overload, chronic infection, or malignancy
Ferritin increased in_______
iron overload, chronic infection, malignancy, viral hepatitis
Ferritin decreased in
iron deficiency
Iron Deficiency causes
Increased loss of iron
Decreased intake/absorption
Decreased release from ferritin
Increased demand on body stores
Fe Deficiency results Total iron: Ferritin: Transferrin: TIBC: % Saturation:
Total: Decreased Ferritin: Decreased Trans: Increased (more available sites) TIBC: Increased % Sat: Decreased
Heme results from Fe deficiency
Decreased RBC ct.
Micro/hypo
Decreased MCH/MCHC
Iron overload referred to as:
Hemochromotosis
Hemochromotosis usually seen as a ________ condition
Hereditary (abn high Fe absorption)
Other causes of iron toxicity
Increased RBC destruction
Decreased Fe utilization
Increased absorption of iron
Defective storage or release of iron
What does Hereditary hemochromotosis cause?
Tissue damage
Hyperpigmentation of skin
Hepatomegaly with liver dysfunction
HH treated by
phlebotomy or chelation
Iron toxicity lab results Total Iron: ferritin: Transferrin: TIBC: % Sat:
Total: Increased Ferritin: Increased Trans: decreased TIBC: decreased (binding sites used up) % sat: Increased
Multiple blood transfusions can cause ______ __________
iron overload
Chromium helps:
maintain normal metabolism of glucose, fat, and cholesterol
Chromium deficiency results in:
Diabetes-like hyperglycemia
Forms of Chromium
Cr(III): Essential
Cr(IV): toxic, carcinogen
Chromium in blood is bound to…
Transferrin
Cr(III) toxicity causes:
allergy-like reaction
Can see _____ Ca, AlkP & Phos in manganese deficiency
increase
Manganese deficiency can cause:
Blood clotting defects, hypocholesterolemia, dermatitis, epilepsy, heart and bone issues, stunted growth
Manganese toxicity can cause:
Nausea/vomiting, HA, memory loss, compulsive laughing & crying
Chronic Manganese deficiency may resemble:
Parkinson’s
Molybdenum found in these foods:
peas, lentils, beans, grains, nuts
T/F: Molybdenum deficiency and toxicity are common
False. They’re rare.
Molybdenum vital to ____ _______ in liver
sulfite oxidase (breaks down sulfite)
Production of uric acid requires this essential element:
Molybdenum
Selenium exposure happens via:
food and sometimes water
_____ is a constituent of glutathione
Selenium
Selenium is closely related with ____
Vitamin E
Keshan disease is:
Selenium deficiency affecting children and women of child-bearing age in China
Kashin-Beck is:
Endemic osteoarthritis in adolescent and preadolescents in northern China, N. Korea, and eastern Siberia.
(areas with low soil selenium levels)
Selenium toxicity caused by:
Selenium sulfide- not found in foods. Possible carcinogen.
