Hematology Flashcards
What clinical features are necessary to consider Thrombotic Thrombocytopenic purpura?
Microangiopathic hemolytic anemia and Thrombocytopenia
What causes Thrombotic Thrombocytopenic purpura?
Inhibition or deficiency of ADAMTS13 (cleaves vWF), leading to vWF multimers
What is the deficiency in Acute Intermittent Porphyria?
Porphobilinogen deaminase
What is the treatment for Acute Intermittent Porphyria?
Hemin- downregulates aminolevulinate synthase
What mutations are common in hereditary spherocytosis?
Scaffolding proteins- ankyrin and spectrin
What are the symptoms associated with hereditary spherocytosis?
hemolytic anemia, jaundice, and splenomegaly. Infection can trigger acute hemolytic crisis
Why can’t mature erythrocytes produce heme?
Mitochondria are required for the first and last 3 steps of heme synthesis
How does posttranscriptional silencing work?
miRNAs and siRNAs are incorporated into RNA-induced silencing complexes. If the RISC and mRNA are a perfect match, they mRNA will be cleaves. If they are a partial match, there will be translational repression, because the ribosome cannot bind
What are the major mechanisms of cell death via ionizing radiation?
DNA double strand break
Free radical formation
What is the surface marker for monocyte-macrophage lineage?
CD14
What is pure red cell aplasia? With which diseases is it associated?
Rare form of marrow failure characterized by hypoplasia of marrow erythroid elements in the setting of normal granulopoiesis and thrombopoiesis.
Associated with thymoma, lymphocytic leukemias, and parvo b19
Why is desmopressin beneficial to patients with von willebrand disease?
Increases vWF factor release from endothelial cells. Also raises circulating levels of factor VIII (hemophilia A)
What is the drug of choice in treatment of heparin-induced thrombocytopenia?
Direct thrombin inhibitor (-rudin, argatroban, dabigatran)
also, stop heparin
Which myeloproliferative disorders have a mutation in JAK2?
Essential thrombocytosis
Polycythemia vera
Primary Myelofibrosis
What is primary myelofibrosis?
Megakaryocytic hyperplasia stimulates fibroblasts, leading to replacement of marrow space with collagen. Hepatosplenomegaly is due to extramedullary hematopoiesis. Teardrop cells
Name the steps and special proteins involved in inflammatory leukocyte migration
- Margination
- Rolling: Sialylated carb groups bind to L-Selectin on neutrophils or E/P-selectin on endothelial cells
- Activation
- Tight adhesion and crawling: Neutrophilic CD 18 beta 2 integrins bind to endothelial ICAM-1
- Transmigration: Neutrophil integrin attachment to PECAM-1
What are the types of leukocyte adhesion deficiencies?
Type 1: absence of CD18, recurrent skin infections sans pus, delayed detachment of umbilical cord
Type 2: less severe
Type 3: similar to type 1
What are the symptoms associated with polycythemia vera?
aquagenic pruritis, facial plethora, splenomegaly
What causes polycythemia vera?
mutation in JAK2, a cytoplasmic (non-receptor) tyrosine kinase
What are heterophile antibodies?
Abs which react to antigens from animal erythrocytes
Which malignancies are associated with EBV?
Burkitt Lymphoma (especially endemic) Nasopharyngeal carcinoma
What are the stop codons?
UAA, UGA, UAG
What determines the prognosis of colorectal adenocarcinoma?
Tumor stage
What is the histological appearance of the spleen in SS patients after repeated infarction?
significant scarring, fibrosis, and atrophy
Why do SS patient have increased folic acid demand?
Increased erythrocyte turnover
What is a common histochemical marker for epithelial-derived tumors?
cytokeratin
What does the HER2 oncogene do?
codes for a human epidermal growth factor receptor with tyrosine kinase activity in the intracellular domain- activates epithelial growth and differentiation, reduces apoptosis.
What drug can be used for HER2 + carcinomas?
Trastuzumab
What are the steps involved in basement membrane penetration?
- detach by reducing E-cadherin expression
- Attach to BM by increasing Laminin
- Invade by releasing proteolyic enzymes
What is haptoglobin?
The thing in blood that binds to hemoglobin after hemolysis
What happens when there is a point mutation in the kozak consensus sequence of the beta globin?
ribosome does not assemble–> translation is not initiated–> beta thalassemia
What symptoms are worrisome for spinal metastases?
advanced age, progressive and persistent pain that is worse at night, not relieved by rest or analgesics, and is accompanied by systemic symptoms
Addition of what substance to a folate-deficient medium can reduce apoptosis?
Thymidine
What are the symptoms of infectious mononucleosis?
sore throat, myalgias, malaise, lymphadenopathy, splenomegaly, and fever
How does EBV infect lymphocytes?
binds to CD-21 on B-cells and infects them. Reactive (atypical) CD 8 T-cells then kill the virally infected B cells
How do reactive (atypical) T-cells look?
Larger with abundant cytoplasm, eccentrically placed nucleus, and cells membrane that conforms to border of other cells.
What stage of the cell cycle do Vinka alkaloids inhibit?
M phase by binding to beta tubulin and preventing polymerization of microtubule proteins
What are the signs and symptoms of multiple myeloma?
bone pain, fatigue, anemia, kidney dz, and hypercalcemia
What is the mechanism of action of bortezomib (boronic acid containing peptide) in MM?
In MM too much Ig is being made- bortezomib inhibits the proteasome, so there is accumulation of toxic intracellular proteins and proapoptotic proteins
Where does complement (C1) bind the Fc portion of IgG or IgM?
The Fc portion closer to the hinge region
What is a common cause for bleeding complications in neonates that do not receive normal care?
Vitamin K deficiency- need prophylactic supplementation. Vit K needed for gamma carboxylation
Which other enzyme deficiency can present similarly to G6PD deficiency?
Glutathione reductase- Along with NADPH, it is necessary for reduction of oxidized glutathione.