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39 Cards in this Set
- Front
- Back
Hemophilia A (classic hemophilia)
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-Factor VIII Defect
-X-linked, Recessive -1 in 10,000 males |
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Hemophilia B (Christmas Disease)
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-Factor IX Defect
-X-linked -1 in 50,000 males |
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von Willebrand Disease
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-von Willebrand Factor Disease
-Not X-linked -1 in 1,000,000 -Looks like Factor VIII Deficiency (since vWF binds VIII in tenase) |
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Antithrombin Deficiency
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-Autosomal dominant trait
-2 to 5 in 10,000 -increased risk of arterial & venous thrombic disease |
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Coagulants
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-includes Factor VIIa, Factor VIII, & Factor IX
-various factors can be administered to treat hemophilia -factor VIIa does not activate factor IX in the absence of tissue factor (therefore factor X can't be activated) -therefore, factor VIIa can be added to blood without initiating the molecular response |
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Coumarin Drugs
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-anticoagulant
-aka warfarin (coumadin) -Vitamin K competitors |
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Heparin
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-anticoagulant
-interacts with & activates antithrombin |
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t-PA
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-anticoagulant
-activates plasmin to initiate fibrinolysis -reduces thrombolysis in early treatment of myocardial infarction |
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Aspirin
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-anticoagulant
-reduces platelet production of thromboxane A2 by inhibiting cyclooxygenases |
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Plavix
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-anticoagulant
-irreversible inhibitor of ADP receptors on platelet membrane |
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ReoPro, Intergrilin, & Aggrastat
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-anticoagulants
-inhibit platelet aggregation by blocking GPIIb-GPIIIa receptor -these inhibitors are reminiscent of Glanzmann Thrombasthenia --> a rare disease caused by a lack of this receptor |
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Platelet Count
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-important screening test in evaluating bleeding problems
-Bleeding problems observed when count is < 100,000uL -Become severe when count < 50,000uL |
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Activated Partial Thromboplastin Time (APTT)
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-test competence of intrinsic pathway after addition of exogenous Ca2+ and a partial thromboplastin (cephalin, kaolin, celite, powdered glass)
-time is prolonged with deficiency in any of the factors in intrinsic pathway or common pathway |
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Thromboplastin Time (PT)
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-tests function of extrinsic pathway by measuring clotting time after addition of a complete thromboplastin (ex. tissue factor) and exogenous Ca2+
-Prothrombin time is prolonged if there is a deficiency in Extrinsic Pathway or Common Pathway |
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Thrombin Time (TT)
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-tests fibrinogen level & function by measuring the clotting time after addition of thrombin
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Bleeding Time (BT)
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-time between infliction of a small standardized cut and the moment it stops bleeding
-rarely used anymore, difficult to standardize |
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Blood Groups
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-Inherited antigens on the surface of RBCs
-Important in transfusion -Important in hemolytic disease of newborns -ABO & Rh antigens are most important (although there are many) |
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Antigen
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-sugar molecules on surface of RBCs
-H antigens used in assembly of these antigens on cell surface -gene is an enzyme that allows one to add one sugar molecule at a time |
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Blood Antibodies
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-if you lack A antigen, you produce anti-A antibodies
-if you lack B antigen, you produce anti-B antibodies -These arise spontaneously (does not require exposure to make/have antibodies) -Usually IgM and IgG antibodies |
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Blood Allele Frequencies
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-polymorphic locus --> each allele maintained at greater than 1% in gene pool
-frequency of phenotypes varies in different populations |
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What are antigens?
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-glycoproteins & glycolipids
-located on RBC membranes -in most tissues (excpet CT, CNS, & some epithelia) -found in body fluids in 80% of people --> called secretors |
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Secretors
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-secrete ABO antigens in body fluids
-80% of people are secretors -controlled by a pair of alleles -SeSe & Sese are secretors -sese are non-secretors |
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Non-secretors
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-both secretors & non-secretors have glycoproteins in their body fluids
-non-secretors just don't have A, B, or H specificities in their body fluids |
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Chemistry of ABO
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-antigenic specificity determined by terminal monosaccharides on oligosaccharide chain
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H gene
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-codes for enzyme (alpha-L-fucosyltransferase), which adds fucose to the terminal galactose of the precursoroligosaccharide to produce H antigen
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A allele
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-codes for enzyme alpha-N-acetly-galactosaminyltransferase, which adds N-acetyl-D-galactosamine to the H antigen
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B allele
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-codes for enzyme alpha-D-galactosyltransferase, which adds D-galactose to the H antigen
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Persons with both A & B alleles
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-produce both enzymes
-some H antigen converted to A antigen & some is converted to B antigen |
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O allele
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-does not code for a functional enzyme
-people with OO --> have H antigen -people with AO or BO have A & H antigen or B & H antigen -nobody has anti-H antibodies |
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In the case of glycolipids, the oligosaccharide chain that carries A, B, and/or H antigenic specificity is attached to...
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the primary hydroxyl groups of sphingosine
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Bombay Phenotype
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-Extremely Rare
-Genotype hh -H gene is defective -No H antigen produced -Therefore A & B have no effect since there is no H subtance for A & B genes to act upon |
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Rh Blood Group (general)
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~85% of US population is positive for Rh anitgen (but genotype frequencies are variable among different populations)
-Rh antigen is part of membrane protein in RBCs |
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Rh Proteins
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-expected to have 12 or 13 transmembrane helical domains
-3 Cys palmitoylation sites -D differs from Ce by 35 amino acids |
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Weak D
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-variant of Rh protein
-produces D antigen at less than normal levels -may be incorrectly classified as Rh negative in blood typing |
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Rh null mutation
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-mutation in which D & CcEe proteins are absent
-these people either lack the DCE gene or have an abnormal regulator of it |
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Rh Blood Group
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-unlike ABO, antigen is a protein
-unlike ABO, antibodies do not occur until exposure of an Rh-negative person to the D antigen in Rh-positive blood -exposure occurs via transfusion or during pregnancy (after exposure to fetal blood) |
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Hemolytic Disease of the Newborn (HDN)
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-when mother is Rh-negative & fetus is Rh-positive
-mother produces antibodies that attack fetal RBCs, causing them to have a shortened lifespan -HDN can occur because of Rh incompatability between mother & fetus, ABO incompatability (mother O, fetus A or B), or an incompatability with other blood group systems like Kell or Duffy (very rare) -fetus will have Erythroblastosis Fetalis |
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Maternal Antigens
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-in ABO systems, maternal pre-existing antibodies are usually IgM and don't cross placenta
-Rh antigens are often IgG & are able to cross placenta |
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Erythroblastosis Fetalis
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-anemia developed due to incompatability between maternal fetal blood types during pregnancy
-mother's anitbodies attack fetal RBCs -Newborn child will be jaundice due to rapid destruction of RBCs --> increased bilirubin -hyperbilirubinemia must be treated to prevent kernicterus (unconjugated bilirubin in brain --> causes brain damage) |