Lecture 8 "Iron and other proteins" Flashcards
What medications can alter iron levels?
antibiotics, birth control, estrogen, hypertension medicine, cholesterol medications, deferoxamine (removes excess iron from the body), gout medication, testosterone
What can increase iron level?
beta-thalassemia, alcoholic cirrhosis, high iron intake, hereditary hemochromatosis
What is the mechanism behind hereditary hemochromatosis increasing iron level?
HFE gene, impaired iron detection and regulation
How does alcoholic cirrhosis increase iron levels?
damage to liver leads to increased ferritin levels (iron storage)
What can decrease iron levels?
iron deficiency anemia, anemia of chronic disease, chronic renal failure, inadequate absorption, increased loss (from GI tract, nose bleeds, menstruation, cancer, trauma, phlebotomy), increased demand in pregnancy
What is the function of ferritin in the body?
it serves as the storage unit for iron
What allows the release of iron through the channels of ferritin when demands occur?
Iron is stored as Fe(III) and then it is oxidized to Fe(II) which allows the release
How much of the body’s iron is stored within ferritin?
15-20%
Where is ferritin stored?
liver, spleen, skeletal muscles, and bone marrow
What is an acute phase reactant?
when ferritin can increase in response to liver disease, cancer, inflammation, and infection
What is the gold standard in diagnosing iron deficiency anemia?
serum ferritin
What can cause increased ferritin?
hereditary hemochromatosis, excess iron intake/poisoning, chronic hepatitis, other chronic disease states (cancer, alcoholism)
What can cause decreased ferritin?
iron deficiency anemia
What are transferrin’s?
they are glycoproteins that are responsible for the transport of iron
How many iron molecules can transferrin bind?
2 iron molecules
How many transferrin binding sites are typically filled?
33%
Where is transferrin synthesized?
transferrin is synthesized in the liver and synthesis increase in a state of iron deficiency
What is total iron binding capacity?
The maximum amount of iron that serum proteins, mainly transferrin, can bind to. TIBC represents the potential from iron binding if ALL of the binding sites on a protein were filled.
What factors increase total iron binding capacity?
iron deficiency anemia, pregnancy, oral contraceptives, viral hepatitis
What factors decrease total iron binding capacity?
anemia of chronic disease, hemochromatosis, sideroblastic anemia
What is transferrin saturation a measurement of?
a percentage of the transferrin binding sites that are actually bound by iron
What causes increased transferrin saturation?
megaloblastic anemia, sideroblastic anemia, iron overload status, hemochromatosis
What causes decreased transferrin saturation?
iron deficiency anemia, chronic infection, malignancy, pregnancy, anemia of chronic disease
What are the components of plasma?
a large majority is water, the blood proteins (globulin, fibrinogen, albumin), nutrients (amino acids, lipids, sugars), and hormones and electrolytes
What are the different types of globulins?
alpha and beta globulins- produced by the liver and are involved in transportation or act as substrates
gamma globulins- produced by lymphoid tissue involved in immune system
What are some purposes Albumin serves?
Functions as the most important regulator of oncotic pressure within the vasculature system. Can also serve as a transporter for hormones, lipids, drugs and other substances.
What causes increased albumin levels?
dehydration
What causes decreased albumin levels?
liver disease, malabsorption, malnutrition, dilution by IV fluids, genetic variations and congenital causes, abnormal loss from renal disease, GI loss, Skin loss, severe burns
What is the function of alpha-1-antitrypsin?
It inhibits the action of many key enzymes that are released during inflammatory reactions in the lungs.
What is an example of an Alpha-1 globulin?
Alpha-1-antitrypsin
What are some deficient alpha-1-ntitrypsis manifestations?
chronic obstructive lung disease in adults, prolonged jaundice or hepatitis in infants, live dysfunction in children, portal hypertension, chronic hepatitis, cirrhosis, hepatocellular carcinoma
Where is ceruloplasmin made and what is its function?
it is made in the liver and is involved in copper transport within the body
What is an example of an alpha-2 globulin?
ceruloplasmin –> contains 6 or seven copper atoms
What causes increased ceruloplasmin?
oral contraceptives, first trimester of pregnancy, infections
What is the function of haptoglobin?
it is produced in the liver and its function is to bind to free hemoglobin when RBCs are destroyed.
What happens once haptoglobin is bound to hemoglobin?
It transports hemoglobin back to the liver where the heme is converted to bilirubin.
What happens to haptoglobin when there is an increase in RBC destruction?
The haptoglobin becomes depleted and its levels decrease.
What can cause hemolytic anemia?
hereditary abnormalities that cause increased RBC destruction, pathogens, infection, inflammation, and toxins
What can cause increased haptoglobin levels?
infection, inflammation, neoplastic disease, pregnancy, trauma, acute MI
What can cause decreased haptoglobin levels?
hemolytic anemia, transfusion reaction, artificial heart valves
What is the function of complement proteins?
they supplement the action of antibodies to destroy and eliminate pathogens from the body
Which complement proteins are considered acute phase reactants?
C3 and C4
When does the complement pathway begin?
The cascade begins when the first protein, C1, recognizes an antibody-antigen complex or when certain components of the surface of a bacteria or virus are recognized.
In the complement pathway what causes inflammation and opsonization?
When C3 is eventually cleaved.
What is the ultimate goal of the complement pathway?
to produce a membrane attack complex (MAC) and insert itself into the membrane of the pathogen, causing lysis and destruction
What is opsonization?
it is the coating of bacterial surfaces which enhances phagocytosis
When may complement levels be reduced?
in any disease that has an increased level of circulating immune complexes or autoimmune antibodies
When may measurement of complement proteins be useful?
in autoimmune diseases such a lupus or recurrent infections.
What is the CH50 test used for?
to measure immune processes or to detect complement deficiency
What is needed in order to have a normal CH50 test result?
all nine proteins C1-C9 must be present
When are C3 and C4 tests primarily used?
used to investigate the undetectable CH50 level
When can C3 and C4 tests be used?
used to monitor some disease such as SLE(lupus). also tested in the presence of certain fungal infections, gram negative septicemia, and shock
When can complement testing (C3,C4) levels be decreased?
systemic lupus erythematosus, bacterial infections, cirrhosis, hepatitis, malnutrition
When can complement testing (C3,C4) levels be increased?
cancer, ulcerative colitis
What produces immunoglobulin’s?
B lymphocytes that then become very specific against individual infections or foreign agents
Where is IgA typically found?
found in secretions along the mucosal epithelium
How does IgA allow for clearance of pathogens?
allows for clearance of pathogens by cilia or of toxins in the GI tract
Where is IgA present?
present in saliva, tears, colostrum, and mucus
What can IgA deficiency cause?
no symptoms can present or it can cause frequent respiratory infections, inflammation of GI tract, or unexplained asthma symptoms
What is IgD found to activate?
basophils and mast cells
When can concentration of IgD increase?
with chronic infections
What is IgE involved in?
key factor involved in allergic reactions and parasitic infections
What is the purpose of an Immunocap?
it can determine specific IgE antibodies against allergens such as dog, cat, dust mites, food, etc…. can also give a total IgE count
What is the most prevalent antibody in serum?
IgG… it also has the longest half life of 23 days
What is IgG responsible for?
responsible for immunity to bacteria and other microorganisms
What do IgM antibodies typically detect?
usually indicate recent infection
When are IgG and IgM testing commonly used?
Epstein Barr Virus, Cytomegalovirus, Herpes I/II testing, Varicella, measles, mumps, rubella
What is multiple myeloma?
a neoplastic disorder which causes proliferation of a monoclonal immunoglobulin, typically IgG and IgA
What parameters of the CMP measure electrolyte function and abnormalities?
sodium, potassium, chloride, CO2, anion gap, calcium
What parameters of the CMP measure renal function?
BUN and creatinine
What CMP parameters measure liver function?
bilirubin, alkaline phosphate, AST, ALP
What are some reasons why someone would order a CMP?
with abdominal pain to check for elevated liver enzymes and renal dysfunction… to evaluate abnormalities of glucose in diabetes… to evaluate potassium and renal function in the treatment of hypertension… to evaluate for liver dysfunction or liver toxicities with medication
What is the ICF predominantly comprised of?
potassium
What is the ECF predominantly comprised of?
sodium
How does the body maintain sodium homeostasis?
by regulating water intake and excretion in the kidneys
What hormones regulate sodium?
mainly antidiuretic hormone (ADH), aldosterone, naturietic hormone
What detects a increase in osmotic pressure?
Osmoreceptors
What detects a decrease in blood pressure?
baroreceptors (aortic arch, carotid sinus)
How can hypernatremia occur?
can result from increased sodium intake or increased water loss… but the body releases ADH and thirst in response
What is the intracellular concentration of potassium?
150 mEq/L
What is the concentration of serum potassium?
4MEq/L
What factors can increase potassium levels?
increased dietary or IV intake, crush injuries or infection, acidotic states
What factors decrease potassium levels?
deficient dietary or IV intake, fluid and electrolyte loss, alkalotic states, diuretics
What controls glucose levels?
glucagon and insulin
What hormones influence glucose levels?
adrenocorticosteroids, ACTH, epinephrine, growth hormone, thyroxine
What factors affect glucose levels on a CMP?
stress, pregnancy, glucose-containing IV fluids, some medications
What factors can increase glucose levels?
diabetes, acute stress response, pancreatitis, certain diuretics, corticosteroid therapy
What factors can decrease glucose levels?
insulinoma (insulin secreting tumor), insulin overdose, starvation, hypothyroidism
What is the main filtering structure in the kidney?
glomerulus
Where does Urea formation occur?
occurs in the liver as a result of the catabolism of protein into amino acids -> free ammonia is formed in the process
What does BUN overall represent?
the metabolic functioning of the liver and excretory function of the kidneys
When can there be an increase in blood urea nitrogen?
high protein diets, gastrointestinal bleeding, dehydration, certain medications, sepsis
When can there be a decrease in blood urea nitrogen levels?
primary liver disease/failure, low protein diets, over hydration
What is creatinine?
a byproduct of catabolism of creatine phosphate which is involved in the contraction of skeletal muscles
Where is creatinine filtered?
filtered by the glomerulus of the kidney
What is creatinine values typically used for?
used with the BUN to obtain information about functioning of kidneys and the GFR
What is creatinine production dependent on?
muscle mass
What can increase creatinine levels?
disorders of renal function, urinary tract obstruction, diabetic nephropathy, rhabdomyolysis, gigantism, acromegaly
What can decrease creatinine levels?
debilitation, decreased muscle mass
Where is calcium more abundant?
more abundant in the ECF than the ICF
What is calcium most involved in?
muscle contraction, cardiac function, neural transmission, clotting cascade
What are the three forms of calcium in the body?
protein bound 40%, complexed 12%, and ionized 48%
What are the protein bound types of calcium?
mostly albumin, but also to alpha, beta 1&2, gamma globin
What are the complexed types of calcium?
w/ phosphate, citrate, bicarbonate, sulfate
What are the ionized types of calcium?
free calcium in its active form
What regulates calcium?
parathyroid hormone (PTH), which is secreted by the parathyroid glands which are located on the thyroid gland
What happens as calcium levels decrease?
PTH is released and calcium is reabsorbed by the kidneys, released from bone and absorption from GI tract is increased
What other test should be ordered if a person had elevated calcium levels?
Ionized calcium (unaffected by albumin protein levels), PTH, check albumin level
What factors can increase calcium levels?
hyperparathyroidism, vitamin D intoxication, tumors, acromegaly
What factors can decrease calcium levels?
hyperparathyroidism, vitamin D deficiency, hypoalbuminemia, malabsorption
What is bilirubin a component of?
bile
Where is bilirubin typically formed?
typically the spleen and reticuloendothelial system
What is unconjugated bilirubin?
when heme is catabolized and forms biliverdin which then becomes bilirubin… before in the liver
What is conjugated bilirubin?
once in the liver the bilirubin is conjugated with glycuronide
What is indirect bilirubin?
unconjugated
What is direct bilirubin?
conjugated
What occurs when bilirubin levels are too high?
jaundice can occur when total serum bilirubin levels exceed 2.5 mg/dL
What is a negative effect of unconjugated bilirubin?
it can pass through the blood brain barrier so if levels are too high and stay high mental retardation and encephalopathy can occur ( >15 mg/dL is critical)
What are some causes of indirect hyperbilirubinemia?
hepatocellular dysfunction (hepatitis, cirrhosis, neonatal hyperbilirubinemia), any disease that increases RBC destruction (transfusion reactions, sickle cell anemia, hemolytic anemia), many medications
What are some causes of direct hyperbilirubinemia?
gallstones, obstruction of extra hepatic ducts by tumor or other cause, liver metastases (obstruction)
What are the main components of serum protein?
albumin: most abundant
globulins
How does renal disease affect serum protein levels?
the glomerulus becomes less able to filter proteins and overwhelms the ability of the renal tubules to reabsorb protein -> leads to loss of protein in urine
What factors cause hyperproteinemia?
dehydration, malignancy, infection
What factors cause hyperproteinemia?
hepatic failure or disease, malnutrition states, malabsorption states, renal failure of disease
What are the functions of albumin?
important regulator of osmotic balance between intravascular and interstitial spaces (albumin pulls water into circulatory system)… act as transporter for drugs, bilirubin, thyroid hormones, and other hormones or enzymes
Why is albumin a poor indicator of nutrition status?
because it has a long half life… pre-albumin is better
What factors can increase albumin levels?
dehydration due to concentration of albumin
What factors can decrease albumin levels?
malnutrition, pregnancy, hepatic disease or failure, protein-losing nephropathies
What enzymes are included in a CMP to test liver function?
alkaline phosphate ALP, aspartate aminotransferase AST, alanine aminotransferase ALT
When can liver function tests have abnormalities?
when there is injury to hepatocytes from alcohol, metabolic disorders, or medications
What is the function of Alkaline Phosphotase?
functions in growth and development of bones, teeth and many other tissues -> essential for bone mineralization
Where are the highest concentrations of ALP?
liver, biliary tract, bone
When is ALP increased? pertaining to liver disorders
cirrhosis of the liver, obstruction of the biliary tract, live tumors, drugs that are toxic to liver
When is ALP elevated? pertaining to bond disorders
cancers that metastasize to the bone, primary cancer of the bone, post-fracture, hyperparathyroidism, growing children
Where is aspartate aminotransferase found in the body?
in metabolic tissue such as heart, liver, skeletal muscle -> if damage occurs in an of these tissues AST is released into circulation and its level increases
When is AST elevated?
liver disease, tumors involving the liver, infectious mononucleosis, skeletal muscle disease or trauma (burns, myositis, muscular dystrophy)
When is Alanine aminotransferase increased?
myositis, myocardial infarction, hepatotoxic drugs, cirrhosis, hepatitis
