Block 6

Question 1

Painless hematuria 2-3 days following an upper respiratory tract infection.

Diagnosis is made by detection of IgA deposits in mesangium of glomeruli on immunofluoresence microscopy.

Cola colored urine.

Answer 1

IgA nephropathy (Berger disease)

Question 2

IgA nephropathy w/ extra-renal syndrome

Skin: purpuric lesions on extensor surfaces of arms, legs, buttocks

GI: ab pain, vomiting, intestinal bleeding, intussusception

Renal: IgA nephropathy

Answer 2

Henloch-Schonlein disease

Question 3

filtration fraction equation

Answer 3

FF = GFR/RPF

where RPF = RBF*(1-hematocrit)

Question 4

what amino acids is elastin made up of?

Answer 4

non-polar amino acids: glycine, alanine, valine

also contains proline and lysine

Question 5

what happens to tropoelastin once it is in the extracellular space?

Answer 5

side chains of some of the lysine residues are covalently bound to form a desmosine crosslink

Question 6

what accounts for elastin’s resilient properties?

Answer 6

extensive desmosine crosslinking (interchain crosslinks involving lysine)

Question 7

in what patients do you see acyclovir resistant VZV (thymidine kinase deficient) and what do you treat it with instead?

Answer 7

tends to only be in AIDS patients

treat with cidofovir because it only requires cellular kinases for activation

Question 8

describe the mechanisms of acyclovir, valacyclovir, famciclovir, and ganciclovir

Answer 8

they are all nucleoside analogs that require both herpes viral and cellular kinases for conversion to their active nucleoside triphosphate form

Question 9

what nerve transmits information from the carotid sinus to the solitary nucleus of the medulla?

Answer 9

glossopharyngeal nerve

Question 10

what are the effects of doing vagal maneuvers such as carotid sinus massage and valsalva?

Answer 10

increase in parasympathetic activity and decrease HR through increase in AV node refractory period

Question 11

describe the pathogenesis of Crohn’s disease

Answer 11

increased activity of Th1 helper cells –> increased production of IL-2, IFN-gamma, and TNF causing subsequent intestinal injury.

Non-caseating granulomas are characteristic

Question 12

crypt abscesses and ulcers, bleeding, no granulomas, Th2 mediated

Answer 12

ulcerative colitis

Question 13

G-protein-linked receptors whose actions are mediated through various secondary messenger pathways

One identified pathway involves increased potassium efflux

Answer 13

mu opioid receptors

Question 14

binding of morphine to mu receptors results in…

Answer 14

G protein-coupled activation of K+ conductance causing hyperpolarization of post-synaptic neurons, blocking pain transmission

Question 15

what causes bile precipitation and biliary sludge?

Answer 15

gall bladder hypomotility

Question 16

an integrase inhibitor that disrupts the ability of HIV to integrate its genome into the host’s chromosomes, thus preventing host cellular machinery from being used to synthesize HIV or mRNA

Answer 16

raltegravir

Question 17

what should you think with the following scenario:

a depressed patient who is getting treatment presents with hypotension, tachycardia, QRS prolongation, frequent premature beats

Answer 17

TCA overdose, which has quinidine-like effect on heart

Question 18

antidote to TCA overdose

Answer 18

hypertonic sodium bicarbinate (NaHCO3)

Question 19

results from an acquired mutation in the PIGA gene that causes absence of the GPI anchor and associated deficiency of CD55 & CD59 complement inhibitor proteins

causes anemia from complement activation

Answer 19

paroxysmal nocturnal hemoglobinuria

Question 20

what is the triad seen in paroxysmal nocturnal hemoglobinuria?

Answer 20

1) hemolytic anemia
2) hypercoagulability
3) pancytopenia

Question 21

HIV gag gene

Answer 21

group-specific antigens in virion core, nucleocapsid proteins p24 and p7

Question 22

HIV pol gene

Answer 22

reverse transcriptase, integrase, protease

Question 23

HIV env gene

Answer 23

envelope glycoproteins gp120 & gp41

Question 24

structural genes of HIV

Answer 24

gag, pol, env

Question 25

regulatory genes of HIV

Answer 25

tat, rev, vif, vpr, nef, vpu

tat and rev are required for relication, the rest are not and are considered accessory genes

Question 26

in patients with essential fructosuria (fructokinase deficiency), what is the primary method of metabolizing dietary fructose?

Answer 26

metabolism of fructose by hexokinase to fructose-6-phosphate

Question 27

what is required for allergens to cause degranulation?

Answer 27

cross-linking of 2 IgE molecules on the surface of the cell by one molecule of allergen

Question 28

digoxin’s side effects

Answer 28

• AV block leading to escape beats –> ventricular tachyarrhythmia
• hyperkalemia
• fatigue, blurry vision, changes in color perception, nausea, vomiting, diarrhea, ab pain, HA, dizziness, delerium

Question 29

characterized by medullary carcinoma of the thyroid, pheochromocytoma, and oral and intestinal mucosal neuromas

Answer 29

MEN2B

Question 30

what is MEN2A associated with that MEN2B is not?

Answer 30

MEN2A is associated with parathyroid hyperplasia

Question 31

delayed type hypersensitivity reactions (DTH)

Answer 31

examples: contact dermatitis, granulomatous inflammation, TB skin test, candida extract skin reaction

mediated by Th1-lymphocytes that release IFN-gamma to cause recruitment and stimulation of macrophages

take days to reach their peak activity