Deck XXI Flashcards Preview

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Flashcards in Deck XXI Deck (33)
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1
Q

What occurs in clotting after platelet activation?

A

Release of mediators (such as ADP and thromboxane A2) and conformational change of glycoprotein IIb/IIIa to bind fibrinogen and form a crosslinked plug.

2
Q

What is the mechanism of action of Abciximab?

A

A glycoprotein IIb/IIIa inhibitor. It inhibits its binding to fibrinogen.

3
Q

What conditions is Abciximab used to treat?

A

Unstable angina, acute coronary syndrome (esp in patients undergoing percutaneous coronary intervention).

4
Q

What is Glanzmann thrombasthenia?

A

Disorder characterized by defective glycoprotein IIb/IIIa on platelet surfaces causing mucocutaneous bleeding. No platelet clumping on peripheral smear.

5
Q

Which proteins drive angiogenesis?

A

Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF). Proinflammatory cytokines (like IGF-1 and INF-y) can indirectly promote angiogenesis through increased VEGF expression.

6
Q

What does ki-67 fraction measure?

A

Proliferation index (ie mitotic index)

7
Q

What condition is characterized by burr cells, helmet cells, and RBC fragments?

A

Traumatic hemolysis which can result from either microangiopathic hemolytic anemia or mechanical damage (i.e. prosthetic valve).

8
Q

What are Burr cells?

A

Erythrocytes with short, evenly spaced projections. They can occur as an artifact or in association with uremia, pyruvate kinase deficiency, microangiopathic hemolytic anemia, or mechanical damage.

9
Q

What distinguishes benign lymph node enlargement from malignant enlargement?

A

Benign enlargement in response to antigenic stimulation is associated with a polyclonal proliferation of lymphocytes; malignancy is associated with a monoclonal lymphocytic proliferation.

10
Q

What findings are seen on light microscopy of GBM?

A

Pseudopalisading tumor cells around areas of necrosis. Necrosis and hemorrhage are also seen on gross examination.

11
Q

What is the key metabolic difference between methotrexate and 5-FU?

A

Methotrexate prevents reduction of folic acid to tetrahydrofolate while 5-FU binds tetrahydrofolate and thymidylate synthetase in a stable reaction intermediate form thereby decreasing the amount of thymidylate synthetase available for thymidine synthesis.

12
Q

How does leucovorin (N5-formyl-tetrahydrofolate) rescue cells from MTX toxicity?

A

It is a tetrahydrofolate derivative that does not require reduction by dihydrofolate reductase before acting as a cofactor for thymidylate synthase. It thus bypasses the dihydrofolate reductase step inhibited by methotrexate.

13
Q

What is a common point in the mechanism of action of MTX and 5-FU?

A

Both effectively inhibit thymidylate formation. The effects of methotrexate can be overcome by folinic acid or leucovorin supplementation however.

14
Q

Myeloblasts stain positive for what?

A

Peroxidase (or myeloperoxidase) in auer rods.

15
Q

Describe the appearance of a myeloblast nucleus.

A

Folded/ bilobed nuclei containing multiple nucleoli. They contain auer rods.

16
Q

What are the clinical manifestations associated with hereditary spherocytosis?

A

Anemia, jaundice, splenomeagly with increased risk of pigmented gallstones and aplastic crisis (parvovirus B19 infection). These sx are caused by splenic sequestration.

17
Q

What test is diagnostic for hereditary spherocytosis?

A

Osmotic Fragility Test.

18
Q

What is the pattern of inheritance for hereditary spherocytosis?

A

Autosomal Dominant.

19
Q

What types of proteins are BRCA1 and BRCA2?

A

DNA repair genes.

20
Q

What laboratory abnormalities are characteristic of multiple myeloma?

A

Erythrocyte rouleaux formation on peripheral smear and Bence-Jones proteins in the urine.

21
Q

What reduces the risk of non-hereditary ovarian cancer?

A

OCPs. They decrease the total number of times that a woman ovulates in her lifetime and thus with fewer ovulatory cycles, there is less need for ovarian surface repair

22
Q

What is the most prominent adverse effect of Cisplatin?

A

Nephrotoxicity (acute tubular injury)

23
Q

What preventative measures must be undertaken for a patient on cisplatin?

A

Amifostine- a thiol based cytoprotective free radical scavenging agent used to decrease cumulative nephrotoxicity. Also, chloride diuresis (via IV NS) keeps cisplatin in the nonreactive state.

24
Q

Hemolytic anemia due to intravascular erythrocyte destruction results in what laboratory findings?

A

Increased serum indirect bilirubin, free hemoglobin in serum and urine, and increased LDH. It also causes decreased serum haptoglobin.

25
Q

What is haptoglobin?

A

A serum protein that binds to free hemoglobin and promotes its uptake by the reticuloendothelial system.

26
Q

When do haptoglobin levels characteristically decrease?

A

When significant quantities of hemoglobin are released into circulation (ex. intravascular hemolysis).

27
Q

What are the lymphoblast types in precursor B-ALL?

A

TdT+, CD10+, CD19+.

28
Q

What are the lymphoblast types in precursor T-ALL?

A

CD2, CD3, CD4, CD5, CD7, CD8, TdT, CD1a

29
Q

What disorders characteristically present with petechial lesions?

A

Platelet disorders.

30
Q

How does Desmopressin acetate (DDAVP) ameliorate symptoms of hemophilia A?

A

Stimulates release of factor VIII and vWF from endothelial cells which temporarily increases factor VIII. It has no effect in hemophilia B.

31
Q

What symptoms are associated with hemorrhagic disease of the newborn?

A

Cutaneous, GI, and intracranial bleeding due to vitamin K deficiency.

32
Q

Patients with Polycythemia Vera have increased incidence of what conditions?

A

Peptic ulceration, itching, gouty arthritis, reversible moderate hypertension.

33
Q

What type of protein is JAK2?

A

A non-receptor tyrosine kinase associated with the erythropoietin receptor (a type I cytokine receptor).