Serum Proteins and Associated disorders Flashcards
Components of blood plasma
Non-cellular liquid layer of the blood obtained by sedimentation and centrifugation
Blood serum (prepared in laboratory)
Whole blood is allowed to coagulate before centrifugation. The resulting fluid is blood serum. Blood serum is blood plasma without blood coagulating factors
Function of albumin
1) Maintenance of osmotic pressure
2) Transport: calcium ions, free fatty acids, bilirubin, hormones and drugs
-Extensively synthesized in the liver and released into the blood
-Small and the most abundant serum protein
3) Binding and transport of calcium ions in the blood
Function of alpha and beta globulins
1) Enzymes
2) Transport
3) Inhibitor proteins
Function of gamma-globulins
Immune response
2 Causes of hypoaluminemia
1) Decreased synthesis of albumin: Kwashiorkor, Liver cirrhosis
2) Increased loss of albumin: Kidney disease-loss into urine due to damage of glomerulus basement membrane, Severe burns–damage of blood vessels leads to huge loss of serum
Alpha-1 globulin fraction includes:
1) Alpha-1 antitrypsin (>90%)
2) Alpha Fetoprotein (AFP)
3) Transcortin
4) Retinol binding protein
A reduced amount of alpha1-Antitripysin in the blood can lead to:
Excessive degradation of elastin in the lung and to emphysema
Hereditary deficiency of alpha1-Antitrypsin results from a defective:
Hepatic N-glycosylation and reduced release into the blood. This can lead to pulmonary and liver disease
Elevated neutrophil elastase:
Destroys elastin in the alveoli
Alpha fetoprotein (AFP) function and type of globulin
AFP is an alpha-globulin that is abundant in fetal plasma which has very low levels of albumin. It may have a function similar to albumin in fetal life. AFP level is low in healthy adults but it increases in cancer and is used as a serum marker for liver cancer.
High maternal serum AFP level may be an indicator of:
Neural tube defects (NTD)
Low maternal serum AFP level may be an indicator of
Down Syndrome
Transcortin and retinol-binding protein are what kind of globulins:
Alpha1-globulins that transport specific lipids in blood
Function of retinol-binding protein:
Transports retinol (vitamin A) in blood from the liver to the peripheral tissues
Transcortin function
alpha-1 globulin: transports 75% of cortisol in blood
Retinol-binding protein function
Retinol (Vitamin A) transport in blood from the liver to the peripheral tissues
The alpha-2 globulin fraction
- Alpha-2 Macroglobulin
- Ceruloplasmin
- Haptoglobin
Function and color of ceruloplasmin
-Ceruloplasmin is a blue alpha-2 globulin
1. Copper transport in blood
2. Ferroxidase activity
Wilson disease
Very low blood levels of ceruloplasmin as hepatic copper binding is deficient. Apoceruloplasmin (without copper) is released into the blood where it is degraded.
“Kayser-Fleischer rings” are present in which disease
Wilson disease
-Damage due to copper accumulation in the liver, leakage into the blood and deposits in brain, eyes, kidney and skin
-Hepatic dysfunction, neurologic and psychiatric symptoms
Haptoglobin
An alpha-2 globulin that binds to free hemoglobin dimers in the blood and prevents loss of Hb in urine.
-Haptoglobin-hemoglobin complex is taken up by macrophages. This explains why acute hemolysis leads to a low serum level of free haptoglobin.
The beta-globulin fraction
- Transferrin
- Hemopexin
- LDL (beta-lipoprotein)
Transferrin
A beta-globulin which transports ferric iron in blood between: intestine, liver, bone marrow and spleen
-Low transferrin saturation is found in patients with iron deficiency as fewer sites of transferrin are filled.
-High transferrin saturation is found in patients with iron overload (High serum iron leads to increased binding)
Function of hemopexin
Hemopexin is a beta-globulin that binds to free heme in the blood and prevents the loss of heme-iron
Antibody found in bloom and lymph and it is the first antibody to be produced in response to an antigen (infection)
IgM
(Smallest and most common) is found in all body fluids. It is produced by repeated exposure to the same antigen. IgG can cross the placenta giving passive immunity to the fetus and newborn
IgG
Is found in the lung, skin, mucous membranes and secreted in allergic reactions
IgE
Is found in body secretions and protects body surfaces. It is the main antibody found in human milk
IgA
IgD
Role in serum is uncertain
Multiple Myeloma
Tumor of the plasma cells and is an example of monoclonal gammopathy.
-Characterized by the presence of high amounts of a single type of immunoglobulin produced by a malignant clone of the cell.
The hepatic acute phase reaction
An overall positive response to prevent damage following an injury such as in:
-Infections
-Extreme stress
-Burns
-Major crush injury
-Allergy or other
Positive acute-phase reactants
Serum proteins that are synthesized in larger amount as they reduce inflammation and deprive microbes of iron.
Examples:
1. apha1-Antitrypsin
2. Ceruloplasmin
3. Haptoglobin
4. Hemopexin
5. Alpha-2 macroglobulin
Negative acute-phase reactants
Serum proteins that are synthesized in smaller amount in order to preserve amino acids for the increased synthesis of positive acute phase reactants.
Examples:
1. Albumin
2. Transcortin
3. Retinol-binding protein
4. Transferrin
C-reactive protein (CRP)
-A hepatic acute phase reactant that does not lead to a peak in SPEP
-Synthesized and released during inflammation and was first found in the blood of patients with acute inflammation. CRP was named after the fact that it reacted with the C-polypeptide of pneumococcus.
