Proteins Flashcards
function of proteins
Nutrition Enzymes Buffers Colloid oncotic pressure Coagulation Immunity Transport
where are most proteins synthesized
liver
proteins can also be synthesized by
immune system (immunoglobulins)
total protein contains
albumin
globulins (α, β, γ)
2 major roles of albumin
transport protein
colloidal osmotic pressure
α1, α2, β globulins
Synthesized by the liver
Functions
‒ Inflammation
‒ Coagulation
‒ Transport proteins
γ globulins (IgG, IgM, IgA)
Synthesized by lymphoid tissue
Function: immunity
Fibrinogen
β globulin
Synthesized by the liver
Functions
‒ Coagulation
‒ Increases during inflammation (positive acute phase protein)
Used as a marker of inflammation
‒Horses, ruminants, camelids
Plasma
Liquid portion of blood that has not clotted
Contains all the proteins!!!
purple, green, and blue top tubes
Serum
Liquid portion of blood that remains after clotting
No fibrinogen
red and tiger top tubes
2 ways to measure protein
refractometer
chemistry analyzer
what interfere with TP measurement on a refractometer
lipids, cholesterol, glucose, urea, hemolysis
T/F icterus will interfere with TP measurement on a refractometer
FALSE!!!
T/F When the TP is reported as a PCV/TP and/or when it is reported on a CBC, it is measured by a refractometer
true
how do chemistry analyzers measure TP
Spectrophotometry
T/F spectrophotometry is more accurate that a refractometer and is very specific
true
When there is a discrepancy in a patient between the total protein measurement on a CBC and a total protein measurement on a chemistry, where is the most likely source of error?
CBC
If both the serum and plasma TP are measured on a chemistry panel from the same patient, which would you expect to be higher?
Plasma
what does movement of depend on with electrophoresis?
- Net charge
- Size and shape of the protein
- Strength of the electrical field
- Type of supporting medium
- Temperature
Proteins on the gel are stained and quantified with a
densitometer
Results are reported as a (electrophoresis)
electrophoretogram
- each protein: percent and absolute amount
Albumin
- Smallest protein
- highest net negative charge
- migrates fastest and closest to anode
globulins
- larger, do not migrate as far
- γ globulins, smallest negative charge; migrate the shortest distance
how is fibrinogen measured
Heat precipitation
- provides an estimate of fibrinogen (uses refractometry)
T/F TP is interpreted with albumin and globulins
true
what is the first thing you think of with hypoalbuminemia
INFLAMMATION!!!
2 main mechanisms of hypoalbuminemia
decreased production
abnormal loss
Hypoalbuminemia: decreased production examples
‒Inflammation (negative acute phase protein) KNOW ME
‒Liver failure or reduction in liver mass (portosystemic shunt)
‒Severe malnutrition, maldigestion, or malabsorption
Hypoalbuminemia: Abnormal loss examples
‒Blood loss (hemorrhage, GI parasites)
‒Intestinal loss: protein-losing enteropathy (PLE)
‒Urinary loss: protein-losing nephropathy (PLN)
‒3rd spacing dilution: effusions and vasculitis
‒Skin disease, burns
how do you find the cause of hypoalbuminemia
1st start with history, clinical signs, PE findings
2nd look to other laboratory findings
if the hypoalbuminemia is caused by hepatic insufficiency what other changes can be present
↓ Glucose
↓ Cholesterol
↓ Urea
↑ Globulins (usually): The liver is not filtering antigens.
if the hypoalbuminemia is caused by protein losing nephropathy what other changes can be present
↑ Cholesterol (usually)
Urinalysis: Increased protein
Urine protein: creatinine ratio
5 signs of nephrotic syndrome
Proteinuria
Hypoalbuminemia
Hypercoagulable (loss of antithrombin III)
Hypercholesterolemia
Ascites
Why might a patient with PLN be hypercoagulable?
Renal loss of antithrombin
what causes hyperalbuminemia
dehydration
3 main mechanisms of hypoglobulinemia
decreased production
abnormal loss
Failure of passive transfer (FPT) in neonates
hypoglobulinemia: decreased production examples
Severe combined immunodeficiency syndrome (SCIDS)
hypoglobulinemia: abnormal loss examples
‒Hemorrhage most common
‒Protein-losing enteropathy (PLE)
3 main mechanisms of hyperglobulinemia
Dehydration
Inflammation
Neoplasia
Hyperglobulinemia: inflammation examples
Infectious: bacterial, viral, fungal, protozoal
• K9 ehrlichiosis
• FIP
Non-infectious: immune-mediated disease, necrosis
polyclonal gammopathy=
inflammation
monoclonal gammopathy=
neoplasia
causes of panhypoprotienemia
blood loss
protein losing enterophathy
causes of panhyperproteinemia
dehydration
will you see a significant shift in TP if fibrinogen is removed?
no, measured in mg/dL; TP measured in g/dL
what kind of globulin if fibrinogen
β-globulin
2 causes of hypofibrinogenemia
liver failure
DIC
2 main mechanisms of hyperfibrinogenemia
inflammation
renal disease
hyperfibrinogenemia: inflammation
‒Positive acute phase reactant protein
‒Inflammatory cytokines → increased synthesis by the liver
hyperfibrinogenemia: renal disease (cats and cattle)
mechanism is unknown
