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Question 1

How does huntingtin mutation in Hungtinton cause disease?

Answer 1

Transcriptional repression through histone deacetylation

Question 2

Does hypermethylation of the promoter region increase or decrease transcription?

Answer 2

Decrease

Question 3

Does the CAG repeat in Huntington cause a gain or loss of function of huntingtin protein?

Answer 3

deleterious (transcriptional repression) gain of function (increased histone deacetylation)

Question 4

Do acetylated histones bind more or less tightly to DNA?

Answer 4

Less

Question 5

What is the triad of Huntington manifestation?

Answer 5

BCD: behavioral abnormality, chorea, dementia

Question 6

What is the term for the tendency for a disease to increase severity and/or start earlier in subsequent generations? (esp trinucleotide repeats diseases)

Answer 6

Anticipation

Question 7

What is pleiotropy?

Answer 7

One gene mutation that leads to multiple phenotypic abnormalities

Question 8

What function do snRNPs serve?

Answer 8

Spliceosomes for removing introns

Question 9

What are the components of a nucelosome?

Answer 9

dsDNA wrapped around a histone protein core

Question 10

How is isoniazid activated by mycobacteria?

Answer 10

Processing by catalase–peroxidase, allowing it to inhibit mycolic acid synthesis

Question 11

Mechanism of mycobacterial resistance to Isoniazid?

Answer 11

Non-expression of catalase-peroxidase enzyme OR

modification of isoniazid’s mycolic acid synthesis enzyme binding site

Question 12

Mechanism of mycobacterial resistance to Rifampin?

Answer 12

Mutation in gene for DNA-dependent RNA polymerase

Question 13

Mechanism of mycobacterial resistance to Ethambutol?

Answer 13

Increased production of arabinosyl transferase

Question 14

What class is streptomycin? Mechanism of resistance?

Answer 14

Aminoglycoside that disables 30S ribosomal subunit. Resistance through modification of binding site.

Question 15

Mechanism of mycobacterial resistance to Pyrazinamide?

Answer 15

Modification of pyrazinamidase, which is necessary to activate it

Question 16

What is the timeframe for acute transplant rejection? Mechanism?

Answer 16

Acute is 1-4 weeks post-transplant. Mechanism is mediated by host T-lymphocyte sensitization against graft MHC.

Question 17

Prevention of acute transplant rejection? Treatment of active acute rejection?

Answer 17

Prevention: calcineurin inhibitors (cyclosporine, tacrolimus)

Tx: corticosteroids +calcineurin inhibitors

Question 18

What are the calcineurin inhibitors?

Answer 18

Cyclosporine, tacrolimus

Question 19

Mechanism for hyperacute transplant rejection?

Answer 19

Preformed anti-ABO ab causing immediate rejection through acute thrombosis of vascular supply.

Question 20

Timeline for chronic transplant rejection? Mechanism?

Answer 20

Timeline: years post-transplant

Mechanism: Host T and B cell sensitization against graft MHC

Question 21

MOA of calcineurin inhibitors?

Answer 21

Inhibit activation and proliferation of Th cells by inhibiting calcineurin and subsequent cytokine synthesis

Question 22

What is the typical brain morphology of prion diseases?

Answer 22

Spongiform encephalopathy, with vacuoles in the cytoplasm of neutrophils and neurons. These can transform to cysts. No inflammation

Question 23

Rapidly progressive dementia and myoclonic jerks are suggestive of what disease?

Answer 23

Creutzfeldt-Jakob disease

Question 24

How do you calculate renal PLASMA flow (RPF) using PAH clearance?

Answer 24

RPF = PAH clearance

PAH clearance = (urine PAH x urine flow rate)/plasma PAH

Question 25

How does RBF relate to RPF?

Answer 25

RBF = RPF/(1-hematocrit)

Question 26

Markers for small cell carcinomas?

Answer 26

Neuron-specific enolase Chromogranin Synaptophysin Neurofilaments

Question 27

What is vimentin useful for diagnosing?

Answer 27

Sarcomas

Question 28

What are cold agglutinins?

Answer 28

Ab against erythrocytes caused by Mycoplasma pneumoniae, EBV, or hematologic malignancy; that lead to agglutination at low temps

Question 29

Mechanism of penicillin resistance? What do you give?

Answer 29

Penicillinase (beta-lactamas) Can give beta-lactamase resistance drugs: oxacillin, nafcillin, methicillin

Question 30

Mechanism of methicillin resistance? Other drugs also resistant?

Answer 30

Alterations in penicillin-binding protein (PBP) structure. Resistant to all beta-lactam agents: oxacillin, nafcillin, methicillin, CEPHALOSPORINS, CARBAPENEMS, etc

Question 31

Resistance to what drugs is conferred by active efflux?

Answer 31

Tetracycline and sulfonamides

Question 32

Resistance to what drugs is conferred by mutation in DNA gyrase?

Answer 32

Fluoroquinolones

Question 33

Resistance to what drug is conferred by mutation in RNA polymerase?

Answer 33

Rifampin

Question 34

What is the first line, disease modifying drug for RA?

Answer 34

Methotrexate

Question 35

What disease-modifying drugs can be added to methotrexate for RA?

Answer 35

Leflunomide and TNF-a inhibitors (etanercept, infliximab, adalimumab)

Question 36

What are the TNF-a inhibitors?

Answer 36

Etanercept, infliximab, adalimumab

Question 37

Methotrexate MOA?

Answer 37

inhibit dihydrofolate reductase, blocking folinic acid synthesis

Question 38

What is the serum inhibitor of extracellular elastase?

Answer 38

alpha1-antitrypsin

Question 39

What would you likely find in the lungs and liver of a patient with a1-AT deficiency?

Answer 39

Lungs: PANacinar emphysema Liver: cirrhosis

Question 40

What is the best drug for treating a woman with osteoporosis who has HTN/CHF?

Answer 40

HCTZ

Question 41

What is the proposed reason for effectiveness of spironolactone in CHF patients?

Answer 41

Inhibition of aldosterone effects, not so much the diuresis

Question 42

Why is activation of the RAAS system bad in CHF patients?

Answer 42

Aldosterone can cause ventricular remodeling, leading to cardiac fibrosis

Question 43

What to give for Alzheimers?

Answer 43

Donepezil (cholinesterase inhibitor), vit E (alpha tocopherol), or Memantine (NMDA-R antagonist)

Question 44

What is a type 2 error (beta)?

Answer 44

Probability of wrongly ACCEPTING null hypothesis

Question 45

What is a type 1 error (alpha)?

Answer 45

Probability of wrongly REJECTING null hypothesis Basically the p-value

Question 46

What is statistical power the "opposite" of?

Answer 46

``` type 2 (beta) error Power = 1 - beta ```

Question 47

Chronic lymphedema is a risk factor for what?

Answer 47

Cutaneous angiosarcoma

Question 48

Axillary lymph node dissection due to what procedure is a risk factor for chronic lymphedema?

Answer 48

Radical mastectomy

Question 49

What is the most potent stimulator for neutrophil chemotaxis?

Answer 49

LTB4

Question 50

Leukotrienes are produced from arachidonic acid by what enzyme?

Answer 50

5-lipoxygenase

Question 51

Demyelination of axons in MS is due to depletion of what cells?

Answer 51

Oligodendrocytes

Question 52

These sx should remind you of what: neuropsych sx incl. Parkinsonian tremor, rigidity, ataxia, slurred speech, drooling, personality changes, depression, paranoia, catatonia

Answer 52

Wilson disease

Question 53

What is the risk of metastasis in a horizontally growing malignant melanoma?

Answer 53

None

Question 54

What is the best prognostic indicator for malignant melanoma?

Answer 54

Depth of invasion (Breslow thickness)

Question 55

What is suggested with bilateral hilar adenopathy and elevated serum calcium and ACE levels?

Answer 55

Sarcoidosis