6/5 UWorlds

Question 1

What is a better test for hypothyroidism, TSH or T3/T4

Answer 1

TSH

TSH levels will rise before T4 levels fall below normal

Question 2

Describe the role that troponin and tropomyosin play in muscle contraction

Answer 2

Tropomysin sits in the myosin-binding sites of actin

Troponin molecules are situated alongside tropomyosin

When Ca2+ binds to troponin C, the Troponin-Ca2+ complex pulls tropomyosin away, exposing the myosin-binding site

Question 3

What disorder is associated with decreased levels of hypocretin

Answer 3

Narcolepsy

Question 4

What bases (A, G, T, U) are present at the 5’ and 3’ splice site of the intron

Answer 4

5’ splice site = GU

3’ splice site = AG

Question 5

What is the single AA mutation in sickle cell vs. hemoglobin C

Answer 5

Sickle cell: Glutamic acid to Valine (THINK: G and V are more far apart so more severe)

Hb C: Glutamic acid to Lysine (THNK: G and L are closer together so milder)

Question 6

What is the presentation of Henoch-Schonlein purpura

Answer 6

• Due to IgA immune complex deposition
  
  • Follows URI infections
• Presentation:
  
  • Palpable purpura on buttocks and legs
  • Arthralgias
  • GI pain and bleeding
  • Hematuria – IgA nephropathy (aka Berger disease)

Question 7

Describe the origin and insertion of the ACL

Answer 7

• Originates on the lateral femoral condyle
• Courses anteriorly and medially to insert on the anterior intercondylar area of the tibia

Question 9

Describe the origin and insert of the posterior collateral ligament (PCL)

Answer 9

• Originates on the medial condyle of the femur
• Courses posteriorly to the posterior head of the tibia

Question 10

What are the CYP450 substrates

Answer 10

• Always Think When Outdoors:
  
  • A - Anti-epileptics
  • T - Theophylline
  • W - Warfarin
  • O - OCPs

Question 13

What are the CYP450 inducers

Answer 13

§ Corona, Guinness, ‘N’ PBRS induce Chronic alcoholism

· C - Carbamazepine

· G - Griseofulvin

· N - Nevirapine

· P - Phenytoin

· B - Barbiturates

· R - Rifampin

· S - St. John’s Wort

· Chronic alcoholism

Question 14

What are the CYP450 inhibitors

Answer 14

§ SICKFACES.COM:

· S - Sodium valproate

· I - Isoniazid

· C - Cimetidine

· K - Ketoconazole

· F - Fluconazole

· A - Acute alcohol abuse

· C - Chloramphenicol

· E - Erythromycin (macrolides)

· S - Sulfonamides

· C - Ciprofloxacin

· O - Omeprazole

· M - Metronidazole

Question 15

What is the clinical presentation of Legionella

Answer 15

Atypical pneumonia

Hyponatremia

Neuro sx (HA and confusion)

Diarrhea

High fever (over 104)

Question 16

What type of cardiac disease is typically associated with hemochromatosis

Answer 16

Dilated cardiomyopathy

Question 17

What type of individuals are eligible for Medicare

Answer 17

Patients > 65 y/o

Patients < 65 with certain disabilities, and those with end-stage renal disease, and ALS

Question 18

Describe the effects/time frame following an MI

Answer 18

• THINK:
  
  • Nothing
• 1 day à Coagulative necrosis
  
  • Inflammation
• 1 week
  
  • Granulation tissue
• 1 month
  
  • Scar formation
• < 4 hours
  
  • Gross changes:
    
    • None
  • Microscopic changes:
    
    • None
  • Complications:
    
    • Cardiogenic shock (cannot provide blood to organs)
    • Congestive heart failure (decreased ejection fraction)
    • Arrhythmias
• 4 – 24 hours:
  
  • Gross changes
    
    • Dark discoloration
  • Microscopic changes:
    
    • Coagulative necrosis (nucleus removed from dead cells)
    • Contraction bands (due to reperfusion injury from hypercontraction)
    • Wavy fibers with narrow, elongated myocytes
  • Complications:
    
    • Arrhythmia
• 1 – 3 days:
  
  • Gross changes
    
    • Hyperemia
  • Microscopic changes:
    
    • Neutrophils
  • Complications
    
    • Fibrinous pericarditis (neutrophils attaching the dead heart will leak out into pericardium)
      
      • Presents as chest pain with friction rub
• 4 – 7 days:
  
  • Gross changes:
    
    • Yellow pallor (due to WBC)
  • Microscopic changes
    
    • Macrophages
  • Complications
    
    • Rupture of ventricular free wall can lead to cardiac tamponade
    • Rupture of interventricular septum
    • Rupture of papillary muscle (fed by R coronary artery) leading to mitral insufficiency
• 1 -3 weeks:
  
  • Gross changes:
    
    • Red border emerges as blood vessel from normal tissue grow into necrotic tissue to form granulation tissue
  • Microscopic changes:
    
    • Granulation tissue with fibroblasts, collage, and blood vessels
  • Complications:
    
    • Arrhythmias
• Months:
  
  • Gross changes
    
    • White scar
  • Microscopic changes:
    
    • Fibrosis
  • Complications
    
    • Aneurysm (scar is not as strong as myocardium)
    • Mural thrombus and embolism (secondary to aneurysm)
    • Dressler syndrome (antibodies against pericardium) occurring 6-8 weeks after infarction
      
      • Chest pain, pericardial friction, and persistent fever

Question 19

What disease typically presents with anemia, renal insufficiency, back pain, and hypercalcemia

Answer 19

Multiple myeloma:

• Malignant proliferation of monoclonal plasma cell within the marrow
  
  • Recall: Plasma cells = mature B-cells that produce immunoglobulin
  • M spike
• Classic presentation:
  
  • Anemia – plasma cells packed in bone marrow inhibit production of other cells (Rouleauz formation)
  • Renal insufficiency – excessive antibodies plug up kidney and form casts
  • Back pain – plasma cells activate osteoclasts
  • Hypercalcemia – plasma cells stimulate osteoclasts

Question 20

What are the 2 types of gastric cancer

Answer 20

Intestinal and diffuse

Question 21

Which gastric cancer is associated with H. Pylori and chronic gastritis

Answer 21

Intestinal type

Question 22

What is a characteristic carcinogen associated with i_ntestinal type_ gastric cancer

Answer 22

Nitrosamines (smoked foods)

This is why intestinal gastric cancer is so prevalent in Japan

Question 23

Describe histology of diffuse gastric cancer

Answer 23

• Signet ring cells (mucin-filled cells with peripheral nuclei)
• Stomach wall grossly thickened and leathery (linitis plastica)

Question 24

What cancer is associated with HTLV-1

Answer 24

Adult T-cell leukemia/lymphoma

Question 25

What disease is cyclin D1 associated with?

Answer 25

Mantle cell lymphoma t(11;14) * THINK: You dine (D1) at a table with a double candle holder (11) on the mantle

Question 26

Describe the mechanism by which Cyclin D1 is an oncogene

Answer 26

Cyclin D activates CDK4 The cyclinD/CDK4 kinase comples phosphorylates Rb protein, allowing progression from G1 to S phase

Question 27

Is p53 an oncogene or a tumor suppressor

Answer 27

* Tumor suppressor

Question 28

What condition is seen with one mutated p53 (only needs one more to express disease)

Answer 28

Li Fraumeni syndrome

Question 29

Describe how unmutated p53 normally prevents uncontrolled cell growht

Answer 29

* Blocks transition from G1 to S phase * In response to DNA damage, p53: * Slows cell cycle and upregulates repair enzymes * If DNA repair is not possible, p53 induces apoptosis * P53 urpegulates BAX, which disrupts Bcl2 (which usually stabilizes the mitochondrial membrane to that cytochrome C doesn’t lead out and activate apoptosis)

Question 30

Is a Rb an oncogene or a tumor suppressor?

Answer 30

tumor suppressor

Question 31

Describe how unmutated Rb usually prevents uncontrolled cell growth

Answer 31

* Blocks transition from G1 to S phase * Rb “holds” the E2F transcription factor, which is necessary for transition to S phase * E2F is release when Rb is phosphorylated by CylinD/CDK4 complex * Rb mutation results in constitutively free E2F, allowing for uncontrolled progression through the cell cycle and uncontrolled growth of cells

Question 32

Is Bcl-2 an oncogene or a tumor suppressor?

Answer 32

Oncogene

Question 33

Describe the function of unmutated Bcl-2

Answer 33

Bcl2 inhibit apoptosis Bcl2 stabilizes the mitochondrial membrane, blocking the release of cytochrome C Disruption of Bcl2 allows cytochrome c to leave the mitochondria and activate apoptosis

Question 34

What disease is associated with Bcl-2 mutation?

Answer 34

Follicular lymphoma t(14;18) * THNK: 18 y/o is when you can buy a gun and start killing people (apoptosis) * Apoptosis occurs in the follicle

Question 35

What inflammatory cells are increased in COPD?

Answer 35

* Inflammatory cells that are increased: neutrophils, macrophages, CD8+ cells * They secrete enzymes and proteases that cause and perpetuate both alveolar destruction of emphysema and mucus hypersecretion found in chronic bronchitis

Question 36

What is the enzyme deficiency and presentation of acute intermittent porphyria

Answer 36

* Deficiency of Porphobilinogen (PBG) deaminase * THINK: Acute intermittent = guys hollering “damn” (deam-inase) intermittently at A CUTE pretty big girl (PBG) walking by * Symptoms – 5 P’s * Painful abdomen, Port wine colored urine (due to increase PGB), Polyneuropathy, Psychological disturbances, Precipitated by drugs (CYP450 inducers), alcohol, and starvation * Treatment * Glucose + heme à inhibition of ALA synthase

Question 37

What is the enzyme deficiency and presentation of porphyria cutanea tarda

Answer 37

* Deficiency of Uroporphyrinogen decarboxylase * Symptoms * · Blistering cutaneous photosensitivity * · Hyperpigmentation * · Hypertrichosis (extra hair) * · Tea colored urine * · Exacerbated with alcohol consumption * · Associated with Hepatitis C * (THINK of a stereotypical homeless man) * Alcoholic, face blistered and dark from sun, facial hair, liver disease

Question 38

What is the presentation of ALA synthase deficiency

Answer 38

Sideroblastic anemia

Question 39

What enzymes are deficient in lead poisoning

Answer 39

ALA dehydratase Ferrochelatase

Question 40

What personality disorder is characterized by hypersensitvity to rejection and socially timid

Answer 40

Avoidant

Question 41

What personality disorder is characterized by disregard for and violation of rights of others; impulsive

Answer 41

Antisocial

Question 42

Is pulomanary hypoplasia a consequence of poly- or oligohydramnios

Answer 42

Oligohydramnios

Question 43

What is the MOA of viral integrase inhibitors

Answer 43

Precents viral dsDNA (already transcribed from viral RNA via reverse transciptase) from inserting itself into host cell DNA

Question 44

What is the MOA of Rifaximin in hepatic encephalopathy

Answer 44

* Is a poorly absorbed antibiotic that will remain in the GI lumen and can eradicate ammonia producing intestinal bacteria * Used to treat hepatic encephalopathy

Question 45

What is the treatment for febrile seizures

Answer 45

Supportive care Can also give antipyretics (acetaminophen or ibuprofen) to decrease fever and improve patient comfort, although this will not reduce risk of further seizures

Question 46

Is Zollinger-Ellison syndrome more likely to cause gastric ulcers or duodenal ulcers

Answer 46

Duodenal - ZE is a tumor of pancreas or duodenum

Question 47

What is the effect of administering secretin to a patient with a gastrinoma?

Answer 47

Secretin paradoxically stimulates gastrin release from gastrinomas

Question 48

What is the function of eosinophils, both in parasitic defense and in type I HSR

Answer 48

* Parasitic defense * § Stimulated by IL-5 produced by Th2 cells and mast cells * § Eosinophils contain Fc receptors that can be bound to IgE or IgE * § These antibodies will bind to parasites, triggering eosinophil degranulation and release of cytotoxic proteins and reactive oxygen intermediates to destroy the parasits * This is antibody-dependent cell-mediated cytotoxicity (ADCC) * Type I HSR * § Eosinophils synthesize prostaglandins, leukotrienes, and cytokines that contribute to the inflammation seen in late-phase type 1 HSR and chronic allergic reactions

Question 49

Do prostaglandins keep ductus arteriosus opened or closed? And thus, are NSAIDs (e.g. Indomethacin) used to maintain patency or close the ductus?

Answer 49

* PDA normally relies on PGE2 to remain open, which declines at birth, allowing DA to close * NSAIDs (e.g. Indomethacin) can be used if you need to promote CLOSURE of the DA

Question 50

An interscalane nerve block, targeting the brachial plexus and used to anesthetize the shoulder and upper arm, may also cause paralysis to what structure?

Answer 50

Diaphragm Causes transient ipsilateral diaphragmatic paralysis in nearly all patients by anesthetizing the roots of the phrenic nerve as they pass through the interscalene sheath This nerve block should be avoided in patients with chronic lung disease or contralateral phrenic nerve dysfunction

Question 51

Which of the acetylcholine esterase inhibitors acts both peripherally and centrally (crosses BBB)?

Answer 51

Physostigmine So can be used to treat atropine overdose

Question 52

Intoxication with what drug causes these sx: Violent behavior, dissociation, hallucinations, amnesia, nystagmus, ataxia

Answer 52

o PCP (phencyclidine) § Hallucinogen

Question 53

Intoxication with what drug causes these sx: Visual hallucinations, euphoria, dysphoria/panic, tachycardia/HTN

Answer 53

o LSD § Hallucinogen

Question 54

Intoxication with what drug causes these sx: Euphoria, agitation/psychosis, chest pain, seizures, tachycardia/HTN, mydriasis

Answer 54

o Cocaine § Stimulant

Question 55

· Intoxication with what drug causes these sx: · Violent behavior, psychosis, diaphoresis, tachycardia/HTN, choreiform movements, tooth decay

Answer 55

o Methamphetamine § Stimulant

Question 56

· Intoxication with what drug causes these sx:· Increased appetite, euphoria, dysphoria/panic, slow reflexes, impaired time perception, dry mouth, conjunctival injection

Answer 56

o Marijuana § Psychoactive

Question 57

Intoxication with what drug causes these sx:Euphoria, depressed mental status, miosis, respiratory depression, constipation

Answer 57

o Heroin § Opioid