Term
| How does the plasma half life of albumin vary among species? |
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Definition
| Albumin half life generally increases with increased body size e.g. 8 day in dogs, 20 days in horses, 2-3 weeks in cattle |
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Term
| What is a protein dyscrasia? |
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Definition
Protein dyscrasia = condition in which the protein has an abnormal structure
dysproteinemia = presence of normal protein at abnormal concentration or presence of abnormal protein in the blood (dyscrasia) |
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Term
| Which two major cytokines stimulate acute phase protein production by the liver? |
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Definition
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Term
| What is the major function of CRP? |
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Definition
| promotes binding of complement to bacteria and induces cytokine production |
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Term
| What is the major function of SAA? |
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Definition
| promotes recruitment of inflammatory cells to a site of inflammation |
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Term
| What is the major function of haptoglobin? |
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Definition
| binds hemoglobin dimers so that iron is not available to microorganisms |
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Term
| What is the major function of ceruloplasmin? |
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Definition
| Enzyme that transports copper and has oxidase activity (helps to convert ferrous (Fe+2) iron into ferric iron for transport in plasma via transferrin) |
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Term
| What is the major function of ferritin and what type of acute phase protein is it? |
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Definition
| storage form of iron (Ferric/Fe+3) mostly in tissues but some enters plasma, positive APP |
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Term
| What iron associated protein is a negative APP? |
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Definition
| Transferrin (major transport protein for Fe+3 in serum,) |
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Term
| What are the two major delayed response proteins (increase 1-3 weeks after onset of inflammation)? |
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Definition
Immunoglobulins (from B lymphs or plasma cells)
Complement proteins (mostly C3, a beta globulin) accumulate in plasma in some inflammatory conditions |
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Term
| Describe the principle for measuring total protein via refractometry |
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Definition
the degree of light refraction in an aqueous solution is proportional to the quantity of solids in the solution --> most solids in plasma are proteins to the refractive index is highly dependent on protein concentration
** use of a temperature compensated refractometer is recommended because its more accurate and requires less calibration |
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Term
| What concentration of glucose or urea is necessary to increased TP via refractometry by 0.6 g/dl? |
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Definition
700 mg/dl glucose
300 mg/dl urea
** so in most circumstances these analytes do not significantly affect total protein concentrations via refractometry |
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Term
| How does lipemia affect refractive index? |
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Definition
| lipemia increased the refractive index --> falsely increased total protein reading |
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Term
| Does hemolysis or icterus falsely increase total protein readings via refractometry? |
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Definition
| No, hemolysis can interfere with reading of the dividing line in the refractometer but neither will falsely increased the refractive index |
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Term
| Describe the principle for measuring total protein via the biuret reaction |
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Definition
copper binds to peptide bonds creating a violet colored complex, therefore the amount of color change (aka the number of peptide bonds) is proportional to the total protein concentration
** not all proteins react well to this reaction, not all proteins are pure polypeptides (e.g. lipoproteins) so they may make up a large proportion of protein in a substance but have fewer peptide bonds than pure polypeptides. |
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Term
| What is the major (positive) interferences associated with the biuret method of measuring total protein? |
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Definition
| hemolysis can cause positive interference Dextran (polysaccharide used as a plasma expander) can also cause a positive interference |
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Term
| What is the principle of the BCG dye-binding reaction for measurement of serum albumin? |
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Definition
BCG (Bromocresol Green), preferentially binds to albumin and produces a color change, the magnitude of which is proportional to the albumin concentration
** the degree of BCG binding varies amongst species, e.g. BCG binds more strongly to bovine albumin than to canine and feline albumin |
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Term
| How does hemolysis interfere with BCG albumin? |
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Definition
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Term
| How do triglycerides interfere with BCG albumin? |
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Definition
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Term
| How does the use of heparinized plasma affect BCG albumin concentrations? |
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Definition
Standard BCG assay: albumin concentrations were higher when using heparinized plasma compared to serum (a proportion of this difference is attributable to the presence of fibrinogen in the plasma samples <-- BCG can bind to fibrinogen).
Modified BCG: albumin concentrations were lower when using heparinized plasma compared to serum |
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Term
| Why is BCP (bromcresyl purple) not typically used to measure albumin in veterinary species? |
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Definition
| BCP doesn't reliably bind to all mammalian albumin and results in false low albumin results in some species (e.g. dogs) |
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Term
| T/F globulin concentration on routine chemistry is measured |
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Definition
False- Globulin concentration is calculated
[TP]-[albumin] = [globulin] |
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Term
| Which species has only three globulin regions on serum protein electrophoresis? |
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Definition
Cattle (alpha, beta, gamma)
vs. dog, cat, horse which have 5 (alpha 1, alpha 2, beta 1, beta 2, gamma) |
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Term
| Which stains in electrophoretic systems have the greatest capability to detect small amounts of protein? |
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Definition
Coomassie brilliant blue
Amido black |
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Term
| Explain the principle of immunoelectrophoresis |
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Definition
| serum proteins are first separated by electrophoresis, then antibodies specific to certain immunoglobulin classes, heavy chains and/or light chains are placed in troughs cut adjacent to the separated proteins. Antibodies and proteins diffuse towards each other and form precipitant arcs if there is a positive reaction |
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Term
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Definition
a protein that doesn't dissolve in pure water (e.g. immunoglobulins)
*sia euglobulin test was originally used to screen for macroglobulins in people but is too nonspecific to be diagnostically useful |
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Term
| What region of the electrophoretogram does IgG3 migrate to? |
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Definition
alpha-2 globulin fraction
*this was described in a horse with multiple myeloma |
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Term
| What region of the electrophoretogram does IgG migrate to? |
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Definition
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Term
| What region of the electrophoretogram does IgM and IgA migrate to? |
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Definition
| beta-gamma junction or beta globulin region |
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Term
| What are two mechanisms for hypoalbuminemia concurrent with a monoclonal gammopathy? |
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Definition
Decreased albumin synthesis secondary to inflammatory cytokines
Negative feedback mechanism involving oncotic pressure receptor on hepatocytes |
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Term
| What type of light chain is most common in antibodies of most domestic species? |
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Definition
Lambda
light chains were 9:1 (lambda:kappa) in plasma cells of healthy dogs, cats, horses, and cattle
** although this may be due to poor cross reactivity with anti-human kappa light chain antibodies |
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Term
| What type of amyloidosis is associated with plasma cell neoplasia? |
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Definition
| AL amyloidosis (composed of immunoglobulin light chains) |
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Term
| What total protein (via refractometer) reading is compatible with 1000 mg/dL of IgG in calves? In horses |
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Definition
5.2 g/dL <-- if a healthy calf has TP equal or greater than 5.2 it has adequate passive transfer
6 g/dL <- adequate passive transfer in a horse
** If the calf is clinically ill a cut off of 5.5 g/dl may be preferable to confirm adequate passive transfer, as hemococentration could be affecting TP concentration rather than actual IgG concentration |
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Term
| T/F hypoalbuminemia attributable to a negative acute phase response will only be seen with chronic inflammatory disease? |
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Definition
| True- takes days to weeks, esp in animal with longer albumin half lives (horses and cattle) ** if inflammation is the ONLY cause the hypoalbuminemia will be mild |
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Term
| What are some potential eteiologies for hypoalbuminemia secondary to B lymphocyte neoplasia? |
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Definition
| inflammatory cytokines, negative feedback secondary to increased oncotic pressure, or end organ damage (e.g. decreased hepatic synthesis, glomerular injury, intestinal injury and malabsorption) |
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Term
| T/F intravascular hemolysis will lower haptoglobin concentrations |
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Definition
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Term
| Describe the principle for measuring fibrinogen concentration via the von Clauss modification of thrombin time method |
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Definition
A high concentration of thrombin is added to a diluted citrated plasma sample. The time it takes for the sample to clot (e.g. fibrin formation) depends primarily on the fibrinogen concentration of the plasma sample
** the lower the fibrinogen concentration, the more time until clot formation |
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Term
| What TP:Fib is compatible with inflammation in cattle? In horses? And what values in each species are compatible with dehydration? |
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Definition
<10 in cattle and <15 in horses
15 (cattle) and >20 (horses) = dehydration |
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Term
| What is a non-immunologic way of measuring haptoglobin? |
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Definition
| Assessment of hemoglobin binding either via spectral differences of bound vs. unbound hemoglobin or by diminished peroxidase activity |
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Term
| What is the principle analytic method for ceruloplasmin assays? |
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Definition
| Spectrophotometric assays based on oxidation of specific substrates |
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Term
| What is the only acute phase protein protein present in sufficient quantities to increase the total protein if increased? |
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Definition
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Term
| Other than inflammation what condition is associated with increased CRP in dogs? |
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Definition
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Term
| What medications can increased haptoglobin concentrations in dogs? |
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Definition
Glucocorticoids
Anthelminthics (potassium melarsonyl, levamisole hydrochloride, milbemycin oxime) |
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Term
| What medication can increase alpha-1-acid glycoprotein concentrations in dogs? |
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Definition
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Term
| What condition other than inflammation is associated with increased CRP in cattle? |
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Definition
| Lactation (esp. during first 4 months) |
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Term
| T/F serum ferritin concentration may increase in horses after strenuous exercise |
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Definition
| True- can remain elevated up to 2 days after exercise |
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Term
| What is the half life of maternal IgG in foals and calves? |
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Definition
| 20 days (up to 30 in some foals) |
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Term
| What concentrations of IgG are consistent with failure of passive transfer in foals? What concentrations are consistent with adequate passive transfer? |
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Definition
| 800 = Adequate passive transfer ** samples collected between 18-48hr after birth |
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Term
| What concentrations of IgG are consistent with failure of passive transfer in calves? |
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Definition
<500-800 = complete FPT
>1000-1600 = adequate passive transfer
** samples collected between 1-8 days after birth |
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Term
| What is considered the gold standard assay for measuring IgG in foals and calves? Describe the principle behind this method |
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Definition
Radial immunodiffusion
Principle: IgG from a serum sample diffused in a gel impregnated with anti (equine or bovine)-IgG antibodies for 18-24h. The diameter of the precipitant ring is proportional to the concentration of IgG in the serum
**caveats: usually too time consuming and expensive for clinical use, some assays in cattle have a positive proportional bias at high concentrations (e.g. overestimate IgG concentration in samples >2000 mg/dL), poor agreement between different RID tests |
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Term
| Describe the principle for the glutaraldehyde coagulation test to measure serum IgG in foals |
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Definition
10% glutaraldehyde promotes formation of molecular cross-links to coagulate basic proteins such as immunoglobulins and fibrinogen. Fibrinogen is absent in serum and there is very little IgM in neonatal foal serum most of the precipitate is proportional to IgG
*** the assay is not great for calves because to assess [IgG] at higher concentrations (1000-1600) to confirm adequate passive transfer, the serum sample needs to be diluted (can ID FPT if the serum does not gel or clot by 60 seconds, equates to <600 mg/dl) |
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Term
| Describe the principle for the ZnSO4 turbidity test to measure serum IgG in foals and calves |
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Definition
Sulfates selectively precipitate cationic (positively charged) proteins such as immunoglobulins. Degree of turbidity of a serum sample when a constant concentration of ZnSO4 is added corresponds to the amount of IgG (very little other Ig isotypes in neonates) and can be visually or spectrophotometrically assessed.
*** This assay is not routinely used in clinic
caveats-
hemolysis can falsely increase results if using spectrophotometry
Marked variation in results in cattle means the assay may not be accurate enough for clinical use.
turbidity occurs in foals between 4-500 (FPT is <200), so this test has been largely replaced in horses |
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Term
| Describe the principle for the Na2SO3 precipitant test for calf serum |
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Definition
Sulfates selectively precipitate cationic (positively charged) proteins such as immunoglobulins. Higher concentrations of sulfites can precipitate lower concentrations of IgG.
Solutions of 14%, 16%, and 18% are used. IF precipitates are seen at all concentrations [IgG] > 1500 mg/dl, If only at 16% and 18% [IgG] = 500-1500, if only at 18% [IgG] < 500
*caveats- semiquantitiative, only works for calves |
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Term
| List congenital immunodeficiencies in cattle |
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Definition
SEVERE COMBINE IMMUNODEFICIENCY (angus): marked lymphoid hypoplasia and no immunoglobunlin
SELECTIVE IGG2 DEFFICIENCY (red Danish cattle, also reported in a holstein)- lack only IgG2, other isotopes are normal
TRANSIENT HYPOGAMMAGLOBULINEMIA (simmental)- delayed production of immunoglobulins |
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Term
| Can you detect IgM or IgA deficiency with SEP? |
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Definition
| No, IgA and IgM represent only a small fraction of beta globulins so deficiency cannot be detected with routine SEP (usually need species specific RID assays etc). |
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Term
| Describe the major concept of the Gibbs-Donnan equilibrium |
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Definition
Sodium (major cation) and chloride (major anion) diffuse between the intravascular and interstitial space to maintain electroneutrality between the two compartments.
The movement of these electrolytes depends predominantly on the concentration of protein (mostly negatively charge b/c albumin is the main one) in the intravascular and interstitial spaces. Because there is more protein in the intravascular space --> greater osmolality in the blood compared with the interstitial space. Serum osmolality also contributes to the COP (although plasma proteins are still the major contributor) |
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Term
| What is the typical hydrostatic pressure of interstitial fluid |
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Definition
-3 mmHg (it's negative due to lymphatic drainage of interstitial spaces and pressure changes in the vena cava)
** so even in the venous side of capillaries where the hydrostatic pressure is low (~10mmHg) the net movement of fluid is into the vessel on the basis of hydrostatic pressure alone |
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Term
| T/F oncotic pressure changes throughout the capillary bed |
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Definition
| False- oncotic pressure depends on the amount of protein in the vasculature which should remain static throughout the capillary bed (vs. hydrostatic pressure which is higher at the arterial side of the capillary) |
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Term
| What substances can interfere with measurement of serum colloidal osmotic pressure |
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Definition
| hemoglobin (both in vivo or in vitro/sample collection associated) and samples that contain hemoglobin based oxygen carriers (e.g. oxyglobin) plasma expanders (e.g. hetastarch, dextran) --> cause positive interference |
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Term
| What proteins typically migrate to the alpha 1 region of a SPE? |
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Definition
alpha 1 lipoprotein (HDL)
alpha 1 antitrypsin and antichymotrypsin (both are positive acute phase proteins) |
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Term
| What proteins typically migrate to the alpha 2 region of a SPE? |
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Definition
alpha 2 macroglobulin (inactivates proteases)
Haptoglobin (binds and transported free Hgb)
**both are positive acute phase proteins |
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Term
| What protein typically migrates to the beta 1 region of a SPE? |
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Definition
transferrin (total iron binding capacity)
**negative acute phase protein |
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Term
| What proteins typically migrate to the beta 2 region of a SPE? |
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Definition
beta 2 lipoprotein (LDL)
C3b
IgM, IgA (not present in sufficient quantity to detect in health)
fibrinogen (if plasma is used) |
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