3/20 UWORLD test #56

Question 1

Q 2. vaccine recommended annually

• what vaccine is this? why annually?
• who is recommended?
• what is in the vaccine? (injection)
• what immune response?

Answer 1

• influenza virus vaccine, annual recommendation due to variable circulating strains per year
• anyone above > 6month of age
• injection vaccine is killed one
  (nasal: live attenuated)
• B cell humoral response

Question 2

Q 3. What is possible consequences (3) of torsades?

Answer 2

• sudden cardiac death: Torsades is consided as ventricular arrythmia
• syncopes
• seizure

Question 3

Q 4. Markers for acute leukemias

• Acute lymphocytic - B and T
• Acute myeloid leukemia

Answer 3

• T cell: CD2-CD8, TdT+
• B cell: CD 10, 19,20, TdT+
• AML: MPO+ (myeloperoxidase)
• TdT (terminal deoxynucleotidyl transferase) is positive for all types of lymphoblast

Question 4

Q 5. histologic finding for Hashimoto

Answer 4

mononuclear cell infiltration with germinal centers

Question 5

Q 7. Apart from CN8, what other trigeminal nerve is associated with sound? innervate what muscle? how exactly is it associated with sound? (volume? pitch? or other?)

Answer 5

CN7

stapedius

auditory volume modulation by reducing noise

Question 6

Q 9. bone stuffs going on with hearing impairment. diagnosis?

Answer 6

Paget’s

Question 7

Q 9. What is receptor for activated nuclear factor kappa-B ligand?

Answer 7

RANK-L

Receptor for Activated Nuclear factor Kappa-b Ligand

Question 8

Q 9. Describe morphologic feature of mature osteoclast

Answer 8

multinucleated cell

Question 9

Q 9. Describe development of osteoclast. What is role of OPG (OsteoProteGerin)?

Answer 9

hematopoeitic stem cell

• > stimulation by M-CSF (macrophage colony stimulating factor)
• > osteoclast precursor -> stimulated by RANK-L
• > mature mutinucleated osteoclast

OPG works as RANK-L decoy receptor, preventing osteoclast maturation

Question 10

Q 11. Where is aortic regurgitation heard?

Answer 10

left sternal border

Question 11

Q 12. ethanol intoxication might impair what metabolism pathway? explain (which step of that specific metabolism is particularly impaired?)

Answer 11

ethanol detoxication -> increased NADH/NAD+ ratio
(alcohol dehydrogenase: requires NAD+)

impaired gluconeogenesis, which also requires NAD+

Particularly, conversion of malate to oxaloacetate
(only malate can cross from mitochondria to cytoplasm. malate then subsequently transformed back to oxaloacetate) requires NAD+: malate dehyrogenase

Question 12

Q 13. Why carbon tetrachloride is toxic?

Answer 12

it causes radical injury

Question 13

Q 14. Where does tibial nerve run?

Answer 13

posteriorly

so does tibial artery/vein

Question 14

Q 16. Enfuvirtide: what is target of this drug?

Answer 14

HIV anti-viral medication
target gp 41
-> prevents penetration of viral particle into target cells

Question 15

Q 17. What is exact mechanism of spironlactone?

Answer 15

aldosterone receptor antagonist

• I thought it is ROMK specific, but NO.
  it can reduce aldosterone mediated sodium retention/ hydrogen secretion as well.

Question 16

Q 18. which histone protein is located outside of the histone core?

Answer 16

H1

H1 serves as linker DNA. It binds to nucleosome outside of histone core and stabilizes chromatin fiber

Question 17

Q 19. How is tamoxifen metabolized to active metabolite?

Answer 17

CYP450

Question 18

Q 24. INH requires what for the activation? how does this explain bacterial resistance against INH?

Answer 18

INH needs to be processed by mycobacterial catalase peroxidase (encoded by KatG)

KatG mutation -> resistance against INH

Question 19

Q 26. Define positive skew

Answer 19

mean > median > mode

Question 20

Q 26. Define negative skew

Answer 20

mode> median > mean

• whether it is positive or negative skew, median is in the middle all the time

Question 21

Q 28. Noise induced hearing loss is result of damage to what structure? where is this structure located?

Answer 21

serociliated hair cells

sterociliated hair cells are located in organ of corti

Question 22

Q 29. What is the most common cause of death from diabetes patient?

Answer 22

coronary artery disease -> MI

• i picked renal failure, but NO. it is CAD

Question 23

Q 30. Patient previously diagnosed with ulcerative colitis, severe abdominal pain, abdominal disintention, signs of shock (hypotension, fever). what is going on? what is preferred method for diagnosis?

Answer 23

toxic megacolon

preferred imaging x-ray. colonoscopy or barium contrast study is not preferred due to potential risk for perforation. Ultrasound is not good way either. it is normally for stones (gallstone, kidney stone) or retriperitoneal bleeding

• toxic megacolon is serious life threatening complication of ulcerative colitis

Question 24

Q 31. Which immune response is required to eliminate Listeria? why?

Answer 24

cell mediated cytotoxic T cell

Listeria has tumbling motility. Using rocket tail, it can move intracellularly and spread cell to cell across membrane. so it can evade antibody

Question 25

Q 32. Defective mineralization of osteoid: what disease is this?

Answer 25

osteomalcia/ rickets

osteoid requires Ca2+ and PO4 for mineralization

Question 26

Q 34. multiple oxalate crystal in kidney tubule: what is going on?

Answer 26

ethylene glycol or vitamin C

-> toxic renal injury

Question 27

Q 40. What structure of elastin is responsible for its elasticity?

Answer 27

interchain CROSS-LINKING