Plasma Proteins Flashcards
What protein is not synthesized by the liver?
Immunoglobulins (B cells and Plasma cells- transformed B cells)
Function of Plasma Proteins
Albumin exerts colloidal osmotic pressure- keeps the protein in our blood vessels. Nutrition, help maintain acid base (albumin= anion), enzymes, Abs, coag factors, hormones, acute phase proteins, transport substances (CALCIUM!)
What are the two main types?
Albumin- 55% of total protein (colloid osmotic pressure!)
Globulins- alpha, beta, and gamma. Include: Immunoglobulins, complement, transferrin (iron transporter), fibrinogen, CRP (c reactive protein), haptoglobin, SAA (serum amyloidase)
Acute phase proteins
Proteins that increase or decrease conc. in plasma in response to inflammatory cytokines. Involved in mediating fever, dropping iron in the face of inflamm (so bugs can’t get the iron), etc.
- extremely sensitive and rises first for inflammation.
- moderate APP, marked APP. Fibrinogen is only moderate which means only increases 5-10 fold, takes a couple weeks to go back down. A couple days to increase. A Marked rises rapidly and goes down rapidly.
Horse vet- use SAA.
Which of the following proteins is not a positive APP?
Negative APP
IN the face of inflamm. it is inhibited (albumin for example- synthesis is inhib.) in favor or producing globulins that are needed.
Positive APP
Fibrinogen for example- ramped up in the face of inflamm.
How do we measure APPs?
CBC, biochem- imp. to understand similarities. Measuring the same thing just in different ways.
Serum- blood has been allowed to clot. Measuring same proteins just minus fibrinogen and other proteins involved in the clotting process. SERUM WOULD BE LOWER (TOTAL PROTEIN)
Whereas plasma- fluid from whole blood- the blood tubes contain EDTA (an anticoagulant) (would be HIGHER because you are measuring all proteins)
What is a refractometer measuring?
Total solids (sometimes called total protein- should annotate by writing ref next to TP). Reported as part of CBC. False increase- glucose, urea, sodium, chloride, gross lipaemia. Haemolysis.
Why measure fibrinogen? How?
Acute phase response. (heating gets rid of fibrinogen). Measure TP of normal plasma vs. heated plasma. The difference equals fibrinogen amount. Using refractometer.
Serum TP
Huge advantage- can measure both TP and Albumin. But you can calculate globulins. Globulins= TP- Albumin. Need to know Globulin for diagnosis/ interpretation.
Serum Protein Electrophoresis
Rarely used in practice but allows quantification and separation of globulins. Differentiated types of globulins- helps with diagnosis. Could it be neoplasia? Was it monoclonal? Is inflammation? Separates proteins based on level of anion. Albumin is attracted most strongly to the source because it is a strong anion. Because it is serum- no fibrinogen.
What is serum missing?
Fibrinogen.
Dysproteinaemia
alternations in protein levels
Problem with refractometers
Is the protein level up or down. Can be useful to also use the PCBTB.
What is a common cause hyperproteinaemia?
Dehydration- equal rise in globulin and albumin. Relative increase due to plasma water loss. Pre-renal azotaemia. sunken eyes, skin tenting, tacky mucous membranes.
What is a common cause of hypoproteinaemia?
Haemorrhage (non selective loss)- so both globuns and albumins would be down
Hyperfibrinogenaemia
Dehydrated but also inflamm- how can you differentiate. Is it true inflamm on top of dehydration? Elevated PP: F ratio to help differentiate. e.g. > 15 in cattle or >20 in horses
Hyperglobulinaemia
Dehydration- relative increase due to plasma water loss.
Inflammation- abs. inc. due to production of positive acute phase proteins and immunoglobulins.
B-lymphocytes neoplasia- multiple myeloma. (need SPE to tell if neoplasia)
Monoclonal
Width is the same or less than albumin. Associated with neoplasia.
Polyclonal
Last peak is all the different types of IgG. Width is larger than albumin. Wide based immunoglobulin peak on electrophoresis. Associated with chronic inflammatory disease.
Massive laceration on a horse- what is happening with protein? Time?
Low protein due to haemorrhage. What if less than 4 hours ago? Protein would show normal. Haemorrhage and loss of protein would depend on when it occurs. 4-12 hours to manifest. TP will appear normal for 4-12 hours.
Hypoalbuminaemia causes
- Increased albumin loss
- Stop producing albumin
- Haemodilution (uncommon)- overzealous fluid therapy. Or rare disease- brain produces too much ADH- so much fluid accumulation.
Hypoalbuminaemia specific causes from increased loss of albumin
Increased loss:
Haemorrage (shows up after fluid redistribution), GI loss (protein losing enteropathy- pretty severe disease to see a drop in albumin), Renal loss, skin loss (protein losing dermatopathy- burns), protein rich effusion (pyothorax)
Hypoalbuminaemia- stop production
Decreased functional hepatic mass (more than 70-80% loss of function), inflamm (negative acute phase protein, mild can take a few days to manifest), maldigestion/ malabsorption (intestinal mucosa disease, exocrine pancreatic insufficiency), malnutrition/ cachexia
