3/14 UWORLD- test # 41

Question 1

Q2. PrP structural conversion from alpha helix to beta pleated sheet

• what disease is this?
• histological change?

Answer 1

Creutzfeldt-Jakob disease (mad cow disease)

spongiform transformation of grey matter

Question 2

Q 1. Ecocardiogram: aorta lying anterior, inferior, and to right of pulmonary artery.

• what is going on?
• which embryological step is messed up?

Answer 2

• transposition of great vessels
• failure of aorticopulmonary septum spiraling

transposition of great vessels occur as aorticopulmonary septum develops in parallel (without spiraling)

Question 3

Q 3. What protein does RAS encode? This protein is in active form when bound to what molecule?

Answer 3

G-protein that mediates RAS-MAPK signaling pathway

GTP bound form is active form

Question 4

Q 6. What is null hypothesis? What is alternative hypothesis?

Answer 4

null hypothesis: hypothesis claiming no difference

alternative hypothesis: hypothesis claiming there is difference

Question 5

Q 6. What is type 1 error? (alpha)

Answer 5

rejecting null hypothesis even though there is no difference in reality

Question 6

Q 6. What is type 2 error? (beta)

Answer 6

accepting null hypothesis even though there is difference in reality

REJECTING NULL FIRST, ACCEPT NULL SECOND
rejecting null hypothesis- type 1 error
accepting null hypothesis- type 2 error

Question 7

Q 6. What is statical power?

Answer 7

1-beta. related to probability of making type 2 error. The greater the statistical power is, the less chance for making type 2 error

Question 8

Q 8. Psychological term “operant conditioning”

• definition
• what are two types? define/example for each

Answer 8

• behavior is produced as it produces punishment or award

1. punishment: decrease behavior
   - positive: giving decrease behavior
   - negative: removal of award decrease behavior
2. reinforcement: increase behavior
   - positive: giving award increases behavior
   - negative: removal of punishment increases behavior

*POSITIVE or NEGATIVE = GIVING or REMOVAL

Question 9

Q 9. What does metyrapone do? what is metyrapone stimulation test look for?

Answer 9

• metyrapone blocks 11-beta-hydroxylase, preventing cortisol synthesis
• metyrapone stimulation test detects whether hypothalamus-pituitary axis is intact. with normal HPA response, blockade of 11-beta-hydroxylase should stimulate further release of ACTH

Question 10

Q 10. bad news. patient does not want to know it possibly due to cultural values. Should physician inform the bad news?

Answer 10

no.

patients have their right to refuse to receive medical information

Question 11

Q 11. CGD- increased risk of infection to what bugs?

Answer 11

catalase positive

N- Norcadia
P- Pseudomona
L- Listeria
A- Aspergilios
C- Candida
E- E coli
S- Staph
S-Serratia
B- B cepacia
H-H.pylori

Question 12

Q 14. Strep pneumo: cocci? or diplococci?

Answer 12

diplococci

Question 13

Q 15. Fever, vomiting, diarrhea, muscle plains, diffuse macular rash resembling sun burn. What is going on?

Answer 13

toxic shock syndrome (TSS)

Question 14

Q 15. TSS (toxic shock syndrome) is mediated by what two cells?

Answer 14

T cells and macrophage

macrophage as antigen presenting cell -> clonal expansion of T cells

Question 15

Q 16. Is etanercept monoclonoal antiboy? what is it?

Answer 15

soluble receptor decoy protein (TNF-alpha receptor)

Etanercept is NOT monoclonal antibody

Question 16

Q 19. With continuous infusion of drug that follows fist-order kinetics, when does drug reach to steady-state level?

Answer 16

about 4-5 half life

Question 17

Q 20. What is macrosomia? what is the common cause of it?

Answer 17

big fetus

maternal diabetes with poor glycemic control

Question 18

Q 20. macrosomic baby due to maternal diabetes. Will baby have transient or persistent hypoglycemia? why?

Answer 18

transient hypoglycemia

insulin synthesized by baby due to glucose transferred from mom will degenerate in several days.

Question 19

Q 21. What is cardiac manifestation of carcinoid syndrome? which side?

Answer 19

valvular fibrous plaques
Right side (before entering pulmonary system)

Question 20

Q 22. For what is D-xylose absorption test used for? what disease? Is it pancreatic enzyme dependent?

Answer 20

D-xylose is monosacchride that does not need to be broken down by pancreatic enzyme. Pancreatic enzyme independent.

D-xylose absorption test is used for brush boarder integrity. Can be used for celiac disease diagnosis

Question 21

Q 24. What is calcitriol?

Answer 21

active vitamin D: (1,25)- OH

Question 22

Q 25. What is leucovorin? what is it used for

Answer 22

folinic acid

to reverse methotrexate induced myelosuppression

Question 23

Q 24. polycystic kidney disease. Changes in
- phosphate
- PTH
- calcitriol
explain physiology

Answer 23

• phosphate: increased, due to reduced phosphate excretion
• PTH: increased, to get rid of phosphate
• calcitriol: decreased, hyperphosphatemia induces
  FGF-23 expression (Fibroblast Growth Factor-23), which blocks phosphate reabsorption. FGF-23 also inhibits calcitriol synthesis.
• it is PHOSPHATE that triggers everything

Question 24

Q 27. Ciprofloxacin: interaction with CYP-450?

Answer 24

CYP-450 inhibitor

Question 25

Q 29. indication of clozapine?

Answer 25

(other) treatment resistant schizophrenia

• think like this: clozapine can cause nasty side effects (agranulocytosis, cardiac myopathy), you only use it for treatment resistant schiz.
  In fact, clozapine is the only drug known for superior efficacy for treatment resistant schiz

Question 26

Q 31. lysed strain A bacteria (that has virulence factor) + live strain B bacteria (that does not have virulence factor)
=> gained infectivity. What mechanism is this?

Answer 26

transformation

DNA released from lysed bacteria is intracellulary transformed to live bacteria, and incorporated into genome => infectivity

Question 27

Q 32. neutrophil findings in megloblastic anemia? why?

Answer 27

hypersegmented neutrophil
megaloblastic anemia is caused by impaired DNA synthesis, making cells divide less.
Less cell division leads to hypersegmentation in neutrophils

Question 28

Q 33. What is parakeratosis? example?

Answer 28

retention of nuclei in corneum startum

ex: psorasis

Question 29

Q 33. Actinic keratosis has increased risk for developing what skin disorder? What predicts its likely to happen?

Answer 29

squamous cell carcinoma

degree of epithelial dysplasia is proportional to risk of squamous cell carcinoma development

Question 30

Q 34. What is pulmonary septic emboli

Answer 30

septic infection may cause tricuspid valve endocarditis (most likely to IV drug users), causing emboli formation

Question 31

Q 35. Suggestion to reduce recurrent kidney stone?

Answer 31

copious water drinking

hydration can dissolve stones

Question 32

Q 37. How does selective arteriole dilator causes increased sodium and fluid retention?

Answer 32

selective arteriole dilator -> baroreceptor sensor due to lowered BP -> increased sympathetic tone -> b1 receptor on JGA -> more renin

Question 33

Q 38. How may multiple sclerosis affect bladder?

Answer 33

bladder hypertonia

-> urinary incontinence

Question 34

Q 39. What part of female reproductive system shows cuboidal epithelial on histology?

Answer 34

ovary

Question 35

Q 40. Which part of aorta is the most common site of rupture due to trauma?

Answer 35

aortic isthmus (near the point where ligamentum arteriosum is attached)