Mix9

Question 1

What part of the body of the infant is typically affected by HPV infection?

Answer 1

True Vocal Cords. Produces symptoms like weak cry, hoarseness, and stridor. HPV has a tropism for stratified squamous epithelium which protectively lines areas that undergo frequent friction and abrasion.

This is why HPV can also affect cervix and anus.

Question 2

What’s the function of milrinone in treating acute decompensated HF?

Answer 2

Milrinone = selective PDE 3 inhibitor. Used in refractory HF due to LV systolic dysfunction. PDE3 converts cAMP to AMP. Increased cAMP serves 2 functions.

1. Positive inotropy - promote Ca2+ influx into cardiac myocyte
2. Vasodilation - ^ cAMP in vascular tissues&raquo_space; systemic arterial and venous dilation&raquo_space; decreased BP
   For this reason, don’t use milrinone in hypotensive Pt.

Question 3

What’s the MOA of darunavir in preventing HIV viral replication?

Answer 3

Protease inhibitor. HIV is transcribed into a single long polypeptide product that needs to be cleaved to activate. Protease inhibitors prevent the maturation of new viruses.

Question 4

Mut in sickle cell disease:

Answer 4

point mutation. missesense. glutamic acid to valine (pos 6) on B-globin gene. Autosomal recessive.

Question 5

Why do you get petechial rash with fat emboli?

Answer 5

Release of mediators from platelets which adhere to and coat the fat emboli&raquo_space; thrombocytopenia. Systemic activation of lipoprotein lipase and intravascular release of toxic levels of oleic acid also contributes.

Question 6

What are the 2 factors required for osteoclast differentiation?

Answer 6

1. Macrophage colony stimulating factor (induces differentiation from hematopoietic stem cell)
2. NFkB - stimulates osteoclast fusion, activation, and survival. Note that the receptor for NFkB signaling is RANK-L Receptor.

Rx - bisphosphonates for Pagets

Question 7

What are the diff indications for bupropion vs buspirone?

Answer 7

Bupropion = NE/dopamine reuptake inhibitor used for major depressive disorder and smoking cessation.

Buspirone = non benzo anxiolytic used for generalized anxiety disorder.

Question 8

What is the cause of lactic acidosis in septic shock?

Answer 8

Lactic acidosis in septic shock is due to tissue hypoxia, which impairs ox phosphorylation and causes shunting of pyruvate to lactate following glycolysis. Hepatic hypoperfusion also contributes to the buildup of lactic acid because liver is primary site of lactate clearance.

This can all happen if there is decreased O2 delivery as in cardiac or pulmonary failure&raquo_space; tissue ischemia/infarction.

Question 9

Alveolar ventilation equation vs minute ventilation equation:

Answer 9

minute ventilation = Tidal volume x breaths/min

alveolar ventilation = (Tidal vol - dead space) x breath/min

Alveolar ventilation does not include dead space volume

Question 10

What messed up muscle is responsible for Zenker diverticulum?

Answer 10

Zenker diverticulum is due to abnormal spasm or diminished relaxation of the cricopharyngeal muscle during swallowing. Food gets stuck in the back of the throat and forms a pouch (*increased intraluminal oropharyngeal intraluminal pressure forces herniation of pharyngeal mucosa through zone of muscle weakness&raquo_space; false diverticulum).

Generally presents in older Pt with oropharyngeal dysplasia, halitosis, regurg, and recurrent aspiration.

Question 11

What’s the most common cause of bronchiolitis in children?

Answer 11

RSV (neg ss linear nongsegmented RNA virus)

Question 12

How does Trypanosoma cruzii cause secondary achalasia?

Answer 12

Produces a neurotoxin that destroy the myenteric plexus and causes intramural, parasymp denervation of the smooth muscle. In the esophagus, this neurotoxin inhibits the LES&raquo_space; food getting “stuck” in the esophagus.

Can also cause megacolon and megaureter this way.

Question 13

Meckel’s diverticulum is an ileal outgrowth that results from failed obstruction of the ___

Answer 13

vitelline (omphalomesenteric) duct.

Generally presents as painless lower GI bleeding. May cause intussusception

Dx by pertechnetate study for uptake by ectopic gastric mucosa.

Question 14

Linezolid is an antibiotic (oxazoledinedione class) that functions by inhibiting 50s subunit and preventing formation of initiation complex. What other drug types should you never prescribe this with?

Answer 14

SSRI. Linezolid has some MAOi activity and when it is prescribed with an SSRI it can cause serotonin syndrome (autonomic instability, altered mental status, neuromuscular hyperactivity)

Question 15

Trastuzumab is a monoclonal Ab used against Her2 positive breast cancer. What kind of receptor does this bind to?

Answer 15

Her2 is a RTK

Question 16

Is Rb activated when hyperphosphorylated or hypophosphorylated?

Answer 16

Active form = hypophosphorylated

• Hyperphosphorylation of Rb allows for progression of cell cycle by releasing E2F transcription factor (allows progression of G1&raquo_space; S)

Question 17

Why can you use digoxin for A-fib with rapid ventricular response?

Answer 17

Digoxin slows ventricular rate by increasing parasymp tone&raquo_space; inhibition of AV nodal conduction.

Can enhance efferent parasymp ganglion transmission and potentiate end organ response to ACh&raquo_space; increased vagal output.