Immuno/Hemolymp Flashcards
Azathioprine MOA
Purine antagonist (thiopurine analog)
inhibits RNA/DNA synthesis
T lymphocyte specific
Converted to 6-mercaptopurine (active form)
Corticosteroids MOA
Impair Fc-mediated phagocytosis
Inhibit antibody production
Reduce complement fixation
Induce T cell apoptosis
IVIG MOA
Blocks Fc receptors (reduce phagocytosis)
Eliminate pathogenic autoantibodies
Inhibit complement activation (blocks C3 and C4)
Interfere with B and T cell activation
Modulates cytokine synthesis
Fas - Fas ligand blockade
Cyclosporine MOA
Calcineurin inhibitor (inhibits T cell activation) Decreases cytokine production (IL-2 important for T cell proliferation)
Mycophenolate MOA
inhibits Inosine Monophosphate dehydrogenase
-inhibits purine synthesis
-T/B lymphocytes depend on de novo pathway
May induce apoptosis in activated T-cells
Impair dendritic cell maturation
Melatonin MOA
stimulate platelet generation (promotes megakaryocyte fragmentation)
inhibit inflammatory response
Leflunomide MOA
Inhibits dihydro-orotate dehydrogenase -pyrimidine synthesis inhibitor decrease DNA/RNA synthesis Inhibits T cell proliferation inhibits B cell antibody production
Vincristine MOA
Accelerated fragmentation of megakaryocytes
-inhibits assembly of microtubules (binds tubulin)
Impairs platelet destruction by macrophages
-inhibits assembly of microtubules
Cyclophosphamide MOA
alkylating agent
disrupts DNA replication
Danazol MOA
interfere with antibody production
interfere with complement and antibody binding
Rituximab MOA
human anti-CD20 B-cell antibody
(CD20 needed for activation, differentiation, growth)
Depletes B cells via complement cytotoxicity
Etanercept MOA
inhibits TNFa (decoy receptor: soluble recombinant TNFa receptor Fc)
Three primary mechanisms leading to anemia?
Blood loss, hemolysis, reduced erythropoesis
T/F: Hemophilia A & B, two serious coagulopathies, affect only males?
True
Examples of infectious agents leading to anemia in dogs and cats?
Dogs: Babesia, Ehrlichia, Anaplasma, Leishmania, Leptospira, Mycoplasma
Cats: FeLV/FIV, FIP, Mycoplasma, Cytauxzoon felis
T/F: Icterus will develop with serum bilirubin concentrations >1.5 mg/dl?
False- greater than 2 mg/dl
T/F: Pigmenturia is noted later in the disease process and only with severe hemolysis?
False- it tends to occur earlier in the disease process of hemolysis and can occur even when mild
Why is cyanosis not a clinical sign of anemia even when hypoxemia is present?
Cynosis can only occur with methemoglobinemia >20% associated with oxidative injury to RBCs (acetaminophen or onion toxicity); there must be at leats 5 g/dl of unoxygenated Hb in the capillaries for cyanosis to be appreciated clinically
List and describe (5) compensatory mechanisms that result in the typical signs of anemia
- Immediate shunting of blood away from tissues with low O2 demand (skin) and toward vital organs. Occurs by selective peripheral vasoconstriction and splenic contraction in dogs
- Cardiac output- increase in HR and contractility initially that increases supply of O2 blood to hypoxic tissues; this may cause a mild systolic flow murmur
- Oxygen delivery enhancement- reduction in Hb-O2 affinity caused by increased metabolic acidity (Bohr effect) and increase in 2,3-DPG in dog RBC
- Decreased activity levels, exercise intolerance, etc especially in acutely anemic animals
- Erythropoetin-mediated accelerated erythropoiesis; this takes 5-7 days
What makes cats more susceptible to formation of heinz bodies?
Feline spleens have a structural variation that results in impaired ability to remove oxidized red blood cells.
Feline hemoglobin also contains more SH groups that are available for oxidation.
Number of reticulocytes that indicates a nonregenerative anemia vs regenerative anemia?
Non-regenerative: 100,000/microliter
Why are nRBC not a good indicator of regeneration in small animals?
They are seen in diseases without anemia or regenerative bone marrow response, such as with lead poisoning, sepsis, heat stroke, neoplasia, HAC
Severe hypochromasia is nearly diagnostic for what type of anemia
Chronic blood loss
List three innate mechanisms of RBC to protect themselves from oxidative damage
Superoxide dismutase, catalase, glutathione peroxidase, glutathione, metHb reductase