Deck XV

Question 1

What result in the Schilling test indicates dietary deficiency of vitamin B12?

Answer 1

Normal urinary excretion of radiolabeled vitamin B12 suggests normal absorption and thus B12 deficiency is due to poor intake.

Question 2

What Schilling test result indicates pernicious anemia?

Answer 2

Diminished urinary excretion of radiolabeled B12. Normal excretion after administration of intrinsic factor is diagnostic of pernicious anemia. Low excretion of B12 after intrinsic factor administration indicates malabsorption syndromes like pancreatic insufficiency, bacterial overgrowth, short gut syndrome.

Question 3

What type of leukemia can be treated by all trans retinoic acid (ATRA)?

Answer 3

Acute promyelocytic leukemia.

Question 4

What gene is fused in patients with APL?

Answer 4

PNL/RARa. The fusion prevents the gene from signalling for proper cellular differentiation.

Question 5

Define anaplastic and describe the features of an anaplastic tumor.

Answer 5

Neoplastic cells that demonstrate a complete lack of differentiation. Tumors bear no resemblance to the tissue of origin and are composed of pleomorphic cells with large, hyperchromatic nuclei that grown in a disorganized fashion. Anaplastic tumors may also contain many abnormal mitoses and giant tumor cells.

Question 6

What is pure red cell aplasia (PRCA)?

Answer 6

A rare form of marrow failure characterized by severe hypoplasia of marrow erythroid elements in the setting of normal granulopoiesis and thrombopoiesis.

Question 7

What conditions are associated with pure red cell aplasia?

Answer 7

Thymoma (autoimmune condition), lymphocytic leukemias, parvovirus B19 infection.

Question 8

What three lab findings are diagnostic of hemolytic anemia?

Answer 8

Elevated LDH, indirect billirubinemia, anemia.

Question 9

What condition is diagnosed by a positive osmotic fragility test?

Answer 9

Spherocytosis.

Question 10

What is a complication of hemolytic anemia?

Answer 10

Pigmented gallstones (composed of calcium bilirubinate, bilirubin polymers, calcium salts)

Question 11

In a lesion involving the jugular foramen, what are the symptoms of jugular foramen (Vernet) syndrome?

Answer 11

CN IX, X, XI dysfunction. Loss of taste from posterior 1/3 of tongue (IX), reduced parotid gland secretion (IX), loss of gag reflex (IX, X), dysphagia (IX, X), dysphonia/ hoarseness (CN X), soft palate drop with uvular deviation towards normal side (X), STM and trapezius paresis (XI).

Question 12

What symptoms are common in a patient with von Willebrand disease?

Answer 12

Easy bleeding from mucosal sites including gingivae, nasal mucosa, GI tract, menorrhagia.

Question 13

Name the two roles of von Willebrand Factor.

Answer 13

Carrier protein for factor VIII; Aids in platelet adhesion to injured blood vessels during clotting by binding platelet glycoproteins and exposed collagen on injured blood vessel walls.

Question 14

Cytokeratin is used as an immunohistochemical marker of what type of tissues?

Answer 14

Epithelial-derived tissues.

Question 15

What is encoded by the HER2/neu oncogene?

Answer 15

A transmembrane glycoprotein with intracellular tyrosine kinase activity. It is a member of the family of epidermal growth factor receptors.

Question 16

What factor, when administered in vitro to animals produces symptoms of cachexia?

Answer 16

TNF-a

Question 17

What symptoms are associated with a factor V Leiden deficiency?

Answer 17

Va is resistant to inactivation by protein C, an antithrombotic. This causes hypercoaguability.

Question 18

Follicular lymphoma is associated with what translocation and what gene expression abnormality?

Answer 18

t(14,18) translocation with Bcl2 overexpression. Bcl2 is a protooncogene (anti-apoptotic effects) causing cell immortality.

Question 19

What are the side effects associated with Vincristine?

Answer 19

Neurotoxicity- peripheral neuropathy. This is the dose limiting side effect.

Question 20

What is the mechanism of action of vincristine (and other vinca alkaloids)?

Answer 20

Inhibition of microtubule polymerization after binding to b-tubulin. M-phase specific agents.

Question 21

How do reticulocyte count, hemoglobin, and erythrocyte count levels change in a patient with a vitamin B deficiency who is started on replacement therapy?

Answer 21

Reticulocyte count increases dramatically upon initiation and hemoglobin and erythrocyte count levels rise more gradually.

Question 22

What are the major adverse effects associated with Ganciclovir?

Answer 22

Neutropenia, anemia, thrombocytopenia, impaired renal function.

Question 23

What is the major side effect associated with zidovudine?

Answer 23

Bone marrow suppression (anemia, granulocytopenia, etc,)

Question 24

What are fibronectins?

Answer 24

Large glycoproteins produced by fibroblasts and some epithelial cells. It binds to integrins, matrix collagen, and glycosaminoglycans and serve as a mediator of normal cell adhesion and migration.

Question 25

How is integrin mediated adhesion of cells to the basement membrane and extracellular matrix mediated?

Answer 25

Through binding of integrins to fibronects, collagen, and laminin.

Question 26

What is the mechanism of action of etoposide?

Answer 26

Inhibition of the sealing activity of topoisomerase II. It causes chromosomal breaks to accumulate in dividing cells and ultimately causes cell death.

Question 27

What is the difference between the actions of topoisomerase I vs topoisomerase II?

Answer 27

Topoisomerase I makes single stranded nicks to relieve negative supercoiling, topoisomerase II induces transient breaks in both DNA strands simultaneously to relieve both positive and negative supercoiling.

Question 28

What two conditions is etoposide most commonly used to treat?

Answer 28

Testicular cancer and small cell lung cancer.

Question 29

What are the two most common organisms causing bacteriemia in sickle cell patients?

Answer 29

Streptococcus pneumoniae followed by hemophilus influenza

Question 30

What is the most common cause of osteomyelitis in a child with sickle cell anemia?

Answer 30

Salmonella (followed by staph. a and e. coli)