UWorld_3.4

Question 1

IF/EM microscopy in Berger’s disease

Answer 1

• Berger = IgA nephropathy
• ==> IgA deposits @ mesangium on IF
  
  • electron dense material on EM

Question 2

Berger’s + extra-renal sx ==> dx?

Answer 2

• Henoch-Schonlein disease

1. skin = purpuric lesions on extensor surfaces of arms, legs, buttocks
2. GI = abdominal pain, N/V, intestinal bleeding and intussusception
3. rena = IgA nephropathy

Question 3

Psych terms:

Acting out =

Isolation =

Undoing =

Answer 3

• acting out = immature defense mechanism; e.g. throwing temper tantrum
• isolation = separation of idea and its accompanying emotions (e.g. w/very stressful/strong emotional situations)
  
  • veteran describing war atrocities in frank, non-emotional terms
• undoing = symbolically nullifying an unacceptable or guilt-provoking though, idea or feeling by confession or atonement

Question 4

Pathophysiology of hemochromatosis

Answer 4

• Hemochromatosis gene (HFE) on chromosome 6 mutation ==> increased iron absorption @ GI tract
  
  • most common mutation = cyst => tyr missense mutation @ aa 282
• one of most common inherited diseases; caucasians/N. european descent
• ==> elevated ferritin and liver cirrhosis

Question 5

Proteins that can be detected via Southwestern blot

Answer 5

• proteins that bind DNA: trxn factors, nucleases, histones
• trxn factors
  
  • c-Jun
  • c-Fos

Question 6

Ras =

Answer 6

• proto-oncogene
• codes for membrane-bound G-protein
• Ras ==> MAP kinase pathway ==> increased trxn

Question 7

S-100 =

Answer 7

• homodimeric calcium-binding proteins
• important in protein phosphorylation and cell growth/differentiation
• marker for cells of neural crest derivation
  
  • melanocytes
  • schwann cells
• marker for Langerhan;s cells and other dendritic cells

Question 8

Increased VMA excretion + adrenal mass ==> dx?

Answer 8

• pheochromocytoma
• arise @ adrenal medulla ==> paroxysmal secretion of catecholamines
• ==> intermittent H/A, palpitations, diaphoresis, HTN

Question 9

Characteristics of MEN syndromes

Answer 9

• MEN = multiple endocrine neoplasms
• MEN 1 (AD) = tumors of parathyroid, pancreas, and pituitary
• MEN 2A (AR) = medullary carcinoma of thyroid, pheochromocytoma, parathyroid tumor
• MEN 2B (AR) = medullary carcinoma of thyroid, pheochromocytoma, mucosal neuromas
• MEN 2A/2B <== RET (proto-oncogene) mutation
  
  • ==> MEN b/c organs are all derived from neural crest cells
  • NCS ==> 4 pharyngeal pouches + adrenal medulla
    
    • ph pouch 4 ==> parafollicular cells of thyroid ==> med. carcinoma of thyroid
    • NSCs ==> mesothelium of adrenal (adrenal medulla) ==> pheo

Question 10

Thyroid cancers (basic)

Answer 10

• parafollicular thyroid cells ==> medullary carcinoma of thyroid
• follicular thyroid cells ==>
  
  • papillary thyroid cancer
  • follicular thyroid cancer

Question 11

muscle/nerve important in eye adduction

Answer 11

• medial rectus m.
• CN III

Question 12

CN III course in brain

Answer 12

• oculmotor nucleus of midbrain
• emerges anterior to midbrain ==> orbit via superior orbital fissure

Question 13

Nerves that mediate corneal reflex

Answer 13

• sensory = nasociliary branch of first division of trigeminal n. (CN V₁)
  
  • enters orbit @ superior orbital fissure
• motor = temporal branch of facial n. (CN VII)

Question 14

Structures entering orbit via superior orbital fissure

Answer 14

• oculomotor nerve (CN III)
• nasociliary branch of CN V₁
• trochlear nerve (CN IV)
• abducens nerve (CN VI)
• superior opthalmic vein

Question 15

Two major types of immunization + mechanism of protection

Answer 15

1. immunize w/bacterial antigen (e.g. capsule-like proteins of S. pneumo)
   
   1. ==> circulating antibodies that activate complement and induce phagocytosis of bacteria
2. immunize w/toxoid (e.g. tetanus, diptheria)
   
   1. ==> circulating antibodies that neutralize bacterial products
   2. these antibodies do not destroy the bacteria itself as the disease is caused by toxins, not by circulating organisms

Question 16

Diuretic overuse impact on blood pH/gases

Answer 16

• diuretic overuse ==> compensatory increase in aldosterone
• aldosterone ==> sodium + H₂O retention + K⁺ and H⁺ loss @ kidneys ==> metabolic alkalosis
  
  • “contraction alkalosis”
• labs = high pH, high HCO₃, high pCO₂

Question 17

[MicroBio] Characteristics of Pseudomonas aeruginosa

Answer 17

• oxidase-positive, non-lactose fermenting, gram (-)
• ==> opportunistic pneumonia @ CF patients
• ==> UTIs in patients w/indwelling catheters

Question 18

[MicroBio] Characteristics of E. Coli

Answer 18

• lactose-fermenting
• gram (-) rode
• ==> complicated and uncomplicated UTIs

Question 19

[MicroBio] Characteristics of K. pneumoniae

Answer 19

• lactose-fermenting
• gram (-) rod
• ==> spontaneous bacterial peritonitis, nosocomial pneumonia, UTIs