Proteins, lipids, carbs Ch 6 D&P Flashcards
Compare serum to plasma proteins.
Plasma has everything, Serum is missing fibrinogen, factor V and factor VIII. (think serum separator)
What accounts for the majority of colloid osmotic pressure of plasma and why?
Albumin. Due to abundance and small size.
What influence does albumin have on coagulation? So what may happen with low albumin?
It dampens platelet aggregation and augments AT III and so low albumin > prothrombotic implications.
What are the types of globulins and where do they come from?
- Alpha and Beta (lipoproteins, acute phase proteins and some globulins like IgM and IgA) ( Made in the Liver.)
- Gamma (B lymphocytes and plasma cells)
What are the different ways to measure TOTAL protein and how sensitive are they in the different types of fluids (3)?
- Biuret method (colorimetric, spectrophotometric) > accuracy for plasma or serum, accurate from 1-10g/dl.
- Precipitation and Dye binding assays > for small amounts, accurate from 10-200mg/dl, for CSF or urine proteins.
- REfractometry for plasma, serum and body cavities (read in g/dL); high conc of glucose, urea, sodium, chloride, lipemia, hemolysis, any turbidity may falsely elevate readings. Icterus doesn’t affect the reading as long as the sample is clear.
How is albumin measured individually most often? What is an alternative way to measure it?
Bromcresol green dye binding method (this is different from total protein measurement).
False high test results occur when levels are very low cause it can bind to other proteins.
Serum protein electrophoresis is an alternative way to quantitate albumin.
How is globulin concentration determined?
Usually calculated by subtracting albumin from total protein in a serum sample.
What Serum IgG concentrations tell you there is failure of passive transfer in a foal or calf?
Below 200mg/dL at 24-48 hrs.
200-400 mg/dL = partial failure
> 800mg/dL = good to go
What are the IgG screening tests for failure of passive transfer? (4)
Zinc sulfate turbidity Latex agglutination Glutaraldehyde coagulation ELISA (remember "LEGZ")
When would you have a decrease or increase in A:G ratio?
Decrease > Renal proteinuria and/or Ig production following following Ag stimulation.
Increase > lack of IgG production in adults or lack of colostrum in foals or calves.
NOTE: THE BODY DOESN’T OVERPRODUCE ALBUMIN.
How is fibrinogen concentration determined?
- Indirectly by refractometry using two centrifuged hct tubes and measuring fibrinogen and then heating the other and measuring it (fibrinogen is precipitated by heat denaturation) and subtracting them and you get fibrinogen in mg/dL.
The method is crude and can be used for hyperfibrinogenemia but not really for hypofibrinogenemia. - its more accurate to determine thrombin clotting time, or use direct automated measurement.
What does hyperalbuminemia tell you?
Dehydration, an absolute increase in albumin doesn’t really happen. (Globulins would also be increased so A:G would be normal unless something else is going on).
What does hyperfibrinogenemia tell you?
Inflammatory or neoplastic dz, its an acute phase protein, and also in dehydration. Early inflammation in large animals. Not on serum biochemical profiles cause its only in plasma.
Hyperglobulinemia may occur under what conditions?
Infection or inflammation
Near term pregnancy
Birds prior to egg laying
Acute phase response cause mild increase (alpha globulins mostly, some beta)
Besides inflammation, or tissue injury, what else results in production of acute phase proteins?
Estradiol
Physical stress
Steroid administration
(extra-hepatic production may also occur)
What stimulates production of acute phase proteins?
IL-1, IL-6, TNF, from macrophages at site of injury and maybe other cells too.
In terms of identifying an inflammatory response, which values are most useful?
- Acute phase proteins (more sensitive than WBC count, can be used in early detection and monitoring response to treatment).
- WBC count
Which tumors often have an elevation of acute phase proteins?
Lymphomas or tumors with significant inflammation.
What are examples of early responding acute phase proteins (within 24 hours) and later responding ones (w/in 48 hours and later)?
Rapid > Amyloid A, C reactive protein
Later > Haptoglobin, fibrinogen, LPS binding protein
(note amyloid a is better than fibrinogen cause it occurs faster and is higher)
Which acute phase protein has the greatest cross-species utility?
Which is best for dogs?
Dogs and cats?
Ruminants and horses?
Cross spp > Serum amyloid A
Dogs > C reactive protein
Dogs and cats > alpha 1 acid glycoprotein
Ruminants and horses > Haptoglobin
If you don’t have blood what may be used to test for acute phase protein?
Saliva
Which coagulation proteins are considered acute phase proteins?
Factors V, VIII and fibrinogen.
Which acute phase protein may be good for monitoring pancreatitis in dogs versus cats?
C reactive protein in dogs.
Serum amyloid A in cats.
What is haptoglobin?
Acute phase protein considered more sensitive than fibrinogen. It binds free hemoglobin and decreases in intravascular hemolysis..
Increases occur in Cushings or steroid admin.
What is Ceruloplasmin?
Copper transport protein. Acute phase protein.
Another important acute phase protein set involving the immune system>
Complement proteins, especially C3.
What is alpha1 acid glycoprotein?
Acute phase protein.
Often elevated in lymphoma, produced by lymphocytes too. (other tumors too)
Increased in FIP and useful to support the dx.
Name three other important acute phase proteins not previously mentioned?
TNF alpha
LPS binding protein
Hepcidin (controls iron availability)
What are 5 important negative acute phase proteins?
Albumin Transferrin (iron txport protein; think cattle and pigs) alpha 2 macroglobulin in cattle Cortisol binding protein Alpha 1 apolipoprotein
What happens with gloulins during nephrotic syndrome?
Increased LDL, beta-lipoprotein, VLDL and alpha 2 macroglobulin result in increased alpha 2 globulins on the serum electrophoretogram. LDL and others increase to to albumin loss nad hypoproteinemia with edema and protein uria.
Which acute phase protein are considered beta globulins?
Transferrin, IgM, hemopexin and/or complement C3 (may also increase in acute liver dz)
Whats indicated by increase in the beta and gamma globulin regions of the serum electrophoretogram?
Ig elevations and these are chronic phase proteins
Bridging of the beta and alpha regions in the serum electrophoretrogram is highly suggestive of what condtion?
Chronic active hepatitis.
Polyclonal gammopathy is associated with what THREE groups of conditions?
Inflammatory
Immune mediated
Liver dz
Monoclonal gammopathy is caused by what and where is the peak on the serum electrophoretogram?
- Also referred to as paraproteinemia
- Produced by a single clone of B lymphocytes or plasma cells.
- Can be located in the ALPHA, BETA or Gamma regions.
- Due to lymphoid neoplasia (plasma cell myeloma, lymphoma, chronic lymphocytic leukemia, macroglobulinemia.
Which non neoplastic conditions may result in Monoclonal gammopathy?
Canine amyloidosis Canine ehrlichiosis Canine visceral leishmaniasis FIP Plasmacytic gastroenteritis
What other important clin path abnormality is seen with monoclonal gammopathy?
Bence Jones proteinuria due to overproduction of IG light chains. Can detect in urine on electrophoresis.
What are some common causes of hypoalbuminemia?
- decreased production due to liver dz, pregnancy, lactation, intestinal malabsorbtion, cachexia, EPI etc.
- Loss of albumin via hemorrhage, proteinuria of renal dz, PLE, exudative skin lesion, burns, intestinal parasitism, high protein effusions
- Nephrotic syndrome (proteinuria, hypoalbuminemia, hypercholesterolemia, azotemia)
- The mild decrease in albumin associated with inflammation as a negative acute phase protein is offset by the increase in alpha and beta globulins so you won’t see hypoproteinemia.
What are the causes of hypoglobulinemia? (3)
Failure of passive transfer
SCID
Agammaglobulinemia; selective IgM, IgA, IgG deficiencies;
What is the main cause of hypofibrinogenemia and how is it detected?
DIC
Thrombin time is best to detect it, heat precipitation is not sensitive enough.
What is the major contributor to COP / colloid osmotic pressure? How is it evaluated?
Plasma proteins, mostly albumin.
Evaluated using colloid osmometer (even works in patients tx’d with synthetic colloids.)
What are troponins?
Intracellular myofibrillar proteins involved in calcium ion regulated striated muscle contraction.
What are the isoforms of troponin used to assess cardiac muscle?
Troponins I and T (cTnI, cTnT).
- cTnI is more sensitive (note the “I” also present in sensitive) and magnitude correlates with severity of injury. (ie in cats with hyperthyroidism, horses on endurance rides and dogs with GDV).(also used to diff cardiac versus non cardiac dyspnea in cats.)
- cTnT increases associated with more severe injury.
What are natruiuretic peptides, endothelin and beta type natriuretic peptides?
- They are indicators of sympathetic nervous system cardio responses and early responders in cardiac injury and are followed by
- endothelin, which indicates alterations in the vasculature.
- Beta type natriuretic peptides show greater utility in diff’ing cardiac from non-cardiac causes of dyspnea than cTnI or atrial natriuretic peptides.