Heme-coag Flashcards
Contents of platelet alpha granules
Protein molecules:
Fibrinogen
PDGF
vWF
P-selectin
PF4
Contents of platelet dense bodies
Nonprotein molecules ADP ATP serotonin (5-HT) Calcium
GPIb/XI/V complex (CD42)
mediates platelt adhesion
Receptor for vWF
GPIIb/IIIa complex (CD41&CD61)
Mediates platelet aggregation,
fibrinogen receptor
GPIaIIa
Mediates platlet adhesion
Collagen receptors
GPIc/IIa complex
Fibronectin receptor
Composition of Heinz body
Clumps precipitated hemoglobin
Hermansky-Pudlak Syndrome
-abnormal dense granules (normally secrete ADP, ATP, 5-HT and calcium) -Epistaxis, oculocutaneous albinism, pulmonary fibrosis, granulomatous colitis -ceroid-like material within tissue macrophages -common in Puerto rico
hereditary spherocytosis
AD inheritance, ANK1 (ankyrin) gene -increased MCHC, and reticulocyte count -PB: spherocytes -sx of extravascular hemolysis Abnormal osmotic fragility and autohemolysis tests (DAT is neg vs AIHA)
hereditary elliptocytosis/ovalocytosis
AD, spectrin alpha chain gene mutations -PB: elliptocytes (twice as long as wide) >25% -*hereditary pyropoikilocytosis (HPP): most common in AA, RBCs sensitive to heat *Stomatocytic type (aka southeast asian ovalocytosis): protects against P. vivax
G6PD deficiency
*G6PD needed to produce NADPH adn reduced glutathione for protection from oxidants; X-linked recessive inheritance -RBCs hypersensitive to oxidant stress (sulfa drugs, nitrofurantoin, primaquine, fava beans, infection) resulting in episodic hemolysis -p/w extravascular hemolysis -PB: bite cells*, Heniz bodies, poikilocytosis, blister cells
Pyruvate kinase (PK) deficiency
-PK catalyzes rate limiting step in glycolysis pathway
AR inheritance
-echinocytes (“burr cells”)
major adult hgb
HbA alpha2 beta2
minor adult hgb
HBA2 alpha2 delta2
Variant beta chain “S”
AA6 Glu–>Val
Variant beta chain “C”
AA6 Glu–>Lys
Relative proportion of Hgb types in sickle cell trait
SA 35-45% HbS 50-65% HbA <3% HbA2
Relative proportion of Hgb types in sickle cell disease
homozygous SS RBC lifespan of 17 days
>80% HbS 1-20% HbF 1-4% HbA2 0% HbA
screening tests for sickle cell
metabisulfite dithionate
Right shift O2 binding curve
Decreased affinity hb acidosis, increased temp, hyperthermia, increased 2,3 DPG,
Left shift O2 binding curve
Increased affinity hb alkalosis, hypothermia, decreased 2,3 DPG