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UNIVERSITY OF TORONTO Faculty of Arts and Sciences APRIL 2011 EXAMINATIONS LMP301H1S DURATION: 2 HOURS Examination Aids: Non-programmable calculators are allowed

Version A

SECTION I – MULTIPLE CHOICE (88 marks) The 44 questions are of equal value (2 marks). Select the most correct answer for each question. 1. Which of the following statements is TRUE regarding lipid biomarkers? i. ii. iii. iv. A. B. C. D. E. Total Cholesterol to HDL-C ratio is more sensitive for heart disease than cholesterol alone Elevated triglycerides are a defining criterion in metabolic syndrome Increase in lipoprotein(a) reflects accumulation of the small-dense form of LDL particles Measurement of Apo-A1 levels is useful in patients with metabolic syndrome at high risk i and ii i and iii iii and iv iv only All of the above (i, ii, iii and iv)

2. Which of the following statements is FALSE regarding regulation of body water? A. B. C. D. E. Receptors in the hypothalamus respond to increased osmolality and stimulate thirst As the effective circulating volume increases, aldosterone secretion is suppressed Congestive heart failure may arise from volume overload of the circulatory system Anti-diuretic hormone stimulates the Na+/K+ transporter to retain sodium and water Angiotensin II stimulates vasoconstriction and sodium resorption in the kidney

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3. Given the following test results: sodium potassium chloride bicarbonate glucose urea creatinine 146 mmol/L (135 - 147) 3.7 mmol/L (3.5 - 5.0) 100 mmol/L (96 - 108) 16 mmol/L (22 - 30) 4.1 mmol/L (4.0 - 6.0) 3.0 mmol/L (5.0 - 7.0) 110 µmol/L (60 - 120) osmolality ketones pH hydrogen ion PCO2 PO2 295 mOsm/kg (280 - 300) negative (negative) 7.45 (7.35 -7.45) 35 nmol/L (35 - 45) 25 mmHg (35 - 45) 75 mmHg (80 - 100)

Which of the following is the most likely explanation for a patient with no known previous medical history? A. B. C. D. E. Chronic respiratory acidosis Chronic respiratory alkalosis Acute respiratory alkalosis Metabolic acidosis Metabolic Alkalosis/Mixed Disorder

4. Which of the following is NOT a characteristic of cancer cells? i. ii. iii. iv. A. B. C. D. E. Loss of cell cycle control Loss of chromosome stability New patterns of gene expression Loss of growth control i and iv i and iii i, ii and iv i, iii and iv All of the above

5. Which storage form of iron is most readily available for mobilization? A. B. C. D. E. Hemosiderin Transferrin Ferritin Apoferritin Cytochrome

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6. Bilirubin is the product of which process? A. B. C. D. E. Protein catabolism in the liver Cholesterol metabolism in the liver Bile acid secretion Degradation of heme from the breakdown of red blood cells All of the above

7. The portal vein: i. i. iii. iv. A. B. C. D. E. Carries nutrient rich blood from the intestine to the liver Carries blood away from the liver Carries more blood to liver than the hepatic artery. Drains bile from liver to gall bladder i and iii i and iv ii and iii ii and iv None of the above

8. Which vascular system connects the gastro-intestinal tract to the liver? A. B. C. D. E. Portal Vein Central Hepatic Vein Hepatic Artery Biliary Tract None of the above

9. Hepatitis may result from: i. ii. iii. iv. A. B. C. D. E. Viral infection High sugar diet Chronic alcohol consumption Milk i.and ii i and iii ii and iii ii and iv All of the above (i, ii, iii, and iv)

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10. A new test was applied to a group of 3500 individuals. A total of 1302 tested positive with the new test. Using the gold-standard diagnostic test among with a positive result, 412 people were actually healthy. If the sensitivity of the new test is 92%, which of the following is TRUE? A. B. C. D. E. The prevalence is 37% The number of false negatives is 890 The number of true positives is 1198 The negative predictive value is 96% The efficiency is 68%

11. Which of the following is NOT a factor in the calculation of the 10-year risk score for cardiovascular disease? A. B. C. D. E. HDL-C Blood pressure Triglycerides Total Cholesterol Age

12. Which of the following statements are likely CORRECT? i. ii. iii. iv. A. B. C. D. E. Thyroid hormones are synthesized from tyrosine Hormone concentrations may vary due to episodic secretion Hypoglycemia suppresses growth hormone secretion The pancreas glands are mainly controlled by the hypothalamic-pituitary-axis i and ii i and iii ii and iii i, ii and iii All of the above (i, ii, iii and iv)

13. Which of the following statements is/are CORRECT regarding DHPLC? i. PCR contamination is not a concern with DHPLC ii. Homoduplexes have a higher melting temperature than those of the corresponding heteroduplexes iii. Single-stranded DNA will elute from the DHPLC cartridge first followed by doublestranded DNA iv. DHPLC is more powerful in screening homozygous mutations than PCR-RFLP

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A. B. C. D. E.

i only i and iv ii and iii i, ii and iv All of the above (i, ii, iii, and iv)

14. Which of the following is/are TRUE regarding a PCR-RFLP based molecular diagnostic method? i. ii. iii. iv. A. B. C. D. E. The target mutations destroy or create a restriction digestion site The optimal temperature for DNA synthesis by Taq polymerase is 37 degrees Celcius It could detect small insertion or small deletion It could be used for screening multiple mutations i only ii only i, iii and iv All of above (i, ii, iii, and iv) None of above

15. Which of following is NOT a risk factor for Type 2 diabetes? A. B. C. D. E. Advanced age Obesity Physical inactivity Smoking None of the above (All are risk factors)

16. A 34 year-old woman is in her 8th month of gestation. She is feeling increasingly tired and weak. Laboratory studies show her hemoglobin to be 97 g/L (120-160 g/L). On the peripheral blood smear, the RBCs show increased variation in size and shape, with many that are hypochromic and microcytic. Which of the following is the most likely cause? A. B. C. D. E. Iron deficiency Gestational Diabetes Hemochromatosis Vitamin B12 deficiency Folate deficiency

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17. Which of the following statements is likely CORRECT regarding liver necrosis? i. ii. iii. iv. A. B. C. D. E. It involves organized degradation and packaging of intracellular constituents The process is activated by TNFα It involves disruption of the membrane with leaking of intracellular contents It results in inflammatory responses i, ii and iii ii and iv iii and iv All of the above None of the above

18. Hepatitis A is a: A. B. C. D. E. Single stranded DNA virus Single stranded RNA virus Double stranded DNA virus Double stranded RNA virus Bacterial pathogen

19. A 39 year-old woman is pregnant with her first child and is given advice by a well-meaning friend. Which statement by the friend is most likely FALSE? A. B. C. D. E. Folic acid in the diet does not change the risk of trisomy 21 Other vitamins are also important and a multi-vitamin supplement is recommended There is good evidence now that ultrasound can be harmful to her unborn baby She should be sure to tell her doctor about pregnancy problems in other family members Folic acid supplements are not of equal benefit for other members of the family

20. In regard to dialysis, which of the following statements is TRUE? i. ii. iii. iv. A. B. C. D. E. Peritoneal dialysis makes use of the patient’s own peritoneum as a diffusion filter Hemodialysis restores the concentrations of potassium and urea back to the normal range Peritoneal dialysis looses efficiency over time and hemodialysis becomes necessary Overly rapid hemodialysis of blood can result in cerebral edema i and ii ii and iii i and iv i, iii and iv All of the above (i, ii, iii and iv)

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21. Which of the following markers of myocardial infarction are NOT entirely specific for cardiac injury? i. ii. iii. iv. A. B. C. D. E. Myoglobin Creatine kinase CK-MB Cardiac troponin i and ii i, ii and iii iii and iv ii only All of the above (i, ii, iii and iv)

22. Which of the following may be associated with metabolic alkalosis? i. ii. iii. iv. A. B. C. D. E. Conn’s syndrome Excessive vomiting Milk-alkali syndrome Diarrhea i and ii ii and iii i, ii and iii i and iv All of the above

23. Which of the following statements about the methionine synthase (MS) enzyme is CORRECT? A. It requires vitamin B6 (pyridoxine) as a cofactor B. A heme-iron moiety is incorporated in the catalytic centre C. It is encoded by multiple genes, which accounts for the complex inheritance pattern of NTDs D. The MS gene contains a SNP that may be associated with increased risk of NTDs E. Normal enzymatic function depends on the presence of a riboflavin (vitamin B2) derivative at its catalytic centre 24. Which of the following statements is most likely INCORRECT? A. B. C. D. E. Hemochromatosis is an autosomal recessive disorder Sickle cell anemia is an autosomal recessive disorder Symptomatic hemochromatosis occurs more often in males than females One of the manifestations of hemochromatosis is Type 1 diabetes Only a fraction of people with a mutant hemochromatosis genotype develop symptoms
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25. The hepatitis serology results are: HBsAg (neg), anti-HCV(neg), anti-HAV(IgG) (pos) and HBsAb (neg). The results are consistent with: A. B. C. D. E. Past infection with hepatitis C Past infection with hepatitis A Chronic infection with hepatitis B Acute infection with hepatitis B None of the above

26. Which of the following statements are TRUE regarding liver tests? i. ii. iii. iv. A. B. C. D. E. The ALT/AST ratio is approximately 3.5 GGT is elevated in cholestasis Conjugated bilirubin is water soluble and can be excreted in urine Alkaline phosphatase is elevated in cholestasis i, ii and iii i and iii ii, iii and iv ii and iv all of the above

27. Which of the following are commonly associated with glucose intolerance? i. ii. i. iv. A. B. C. D. E. Graves’ disease Addison’s disease Diabetes insipidus Polycystic ovarian syndrome i and iv ii and iii ii and iv iii and iv All of above (i, ii, iii, and iv)

28. A family doctor notices that her 39 year old patient’s serum creatinine rose from 100 to 110 mol/L (normal 60-120 mol/L) since his visit last year. She is NOT likely concerned because of which of the following possible explanations? A. B. C. D. E. He had taken up body building since his last visit He went to the another laboratory which has a different methodology The laboratory’s method is imprecise and needs to reduce variability in their assay All of the above None of the above
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29. Which of the following is NOT an advantage of biochemical testing? A. B. C. D. E. Common tests methods available in many laboratories that provide results quickly Tests are available that are sensitive and/or specific for certain diseases A small amount of sample is often enough for analysis Blood specimens are relatively easy and safe to obtain None of the above (All are true)

30. Which of the following pairs biochemical markers and corresponding organ/tissue of origin is INCORRECT? A. B. C. D. E. Atrial naturetic peptide / heart Gamma glutamyl transferase / liver Creatine kinase / muscle Erythropoietin / kidney Renin / adrenal

31. Given the following test results: sodium potassium chloride bicarbonate glucose urea creatinine 141 mmol/L (135 - 147) 5.1 mmol/L (3.5 - 5.0) 104 mmol/L (96 - 108) 11 mmol/L (22 - 30) 17.6 mmol/L (4.0 - 6.0) 7.4 mmol/L (5.0 - 7.0) 121 µmol/L (60 - 120) osmolality ketones pH hydrogen ion PCO2 PO2 310 mOsm/kg (280 - 300) 4+ (negative) 7.24 (7.35 -7.45) 58 nmol/L (35 - 45) 25 mmHg (35 - 45) 108 mmHg (80 - 100)

Which of the following is the most likely explanation for a patient with no known previous medical history? A. B. C. D. E. Acute respiratory acidosis Renal Failure Ketoacidosis Lactic acidosis Alcohol poisoning

32. The term cancer refers to: A. B. C. D. E. Cell division Uncontrolled growth Cell death A and B B and C

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33. Individuals with impaired fasting glucose and impaired glucose tolerance are at increased risk of the following EXCEPT: A. B. C. D. E. Type 2 diabetes Heart disease and stroke Type 1 diabetes Hypertension None of the above (All are risk factors)

34. The main routes of transmission for both hepatitis B and C include: i. ii. iii. iv. A. B. C. D. E. Ingestion of contaminated food/water Organ transplant/Blood transfusion Sexual transmission Perinatal (mother to child) i, ii and iii ii, iii and iv ii and iiii ii and iv All of the above

35. Which of following is NOT a risk factor for Type 1 diabetes? A. B. C. D. E. Family history Genetic background Autoimmune disease Environmental None of the above (All are risk factors)

36. According to the most recent Canadian Diabetes Association Guidelines, a diagnosis of Type 1 diabetes may be confirmed by the findings of: A. B. C. D. E. Weight loss Polydipsia and polyuria Oral glucose tolerance test of ≥ 7.0 mmol/L after 2 hours Random plasma glucose ≥ 11.1 mmol/L Fasting plasma glucose ≥ 7.0 mmol/L

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37. Which of the following statements is FALSE regarding acute renal failure? A. B. C. D. E. Protein deposition of myoglobin in the nephron leads to glomerulonephritis Toxins may cause loss of renal function due to tubular necrosis Urinary renal stones may block urine flow Treatment with fluids can reverse the condition if caused by hypotensive shock None of the above (All are true)

38. Which of the following statements are FALSE regarding congenital hypothyroidism? i. Severe cases were also called myxedema ii. It is included in newborn screening programs iii. If the affected infants are left untreated, they can develop mental retardation iv. TSH supplementation is the effective treatment A. B. C. D. E. i and iv i and ii ii and iii i, ii and iii All of the above are false

39. Which of the following is NOT a conventional tumour marker? A. B. C. D. E. Immunoglobulins Human Chorionic Gonadotropin (HCG) Progesterone Calcitonin Creatinine

40. Which of the following statements is INCORRECT? A. B. C. D. E. PKU carriers have 50% of Phenylalanine hydroxylase (PAH) enzyme activity PKU carriers have no phenylalanine hydroxylase (PAH) enzyme activity Tyrosine is the main product of the PAH enzyme reaction PKU may be due to phenylalanine hydroxylase enzyme defects PKU may be due to biopterin defects

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41. Which of the following reasons would NOT constitute a justification to include a test in a newborn screening panel? A. The disorder produces irreversible tissue/organ damage by the time clinical signs are evident B. Effective treatment is available that prevents irreversible damage C. A reliable screening test can be provided at low cost D. Testing can help identify other affected family members E. None of the above (All are valid reasons) 42. Which enzyme is involved in the conversion of unconjugated bilirubin (insoluble form) to conjugated bilirubin (soluble form)? A. B. C. D. E. Gamma glutamyl transferase UDP-glucuronyltransferase Heme oxygenase Aspartate aminotransferase None of the above

43. The major risk factors for hepatitis A include: i. ii. iii. iv. A. B. C. D. E. Eating food prepared by an infected person Living in close quarters with other individuals (e.g. students, prisoners) Travel to countries with endemic hepatitis A infection and poor sanitary conditions Obtaining multiple tattoos i and iii i, ii and iii ii and iv iv only All of the above

44. The hepatitis serology results are: HBsAg (neg), HBcAb-IgM (neg), HBsAb (pos) and antiHCV (neg). These results are most consistent with: A. B. C. D. E. Past infection with hepatitis B Chronic infection with hepatitis C Acute infection with hepatitis B Acute infection with hepatitis C None of the above

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SECTION II – Short Answer (12 marks) 1. The following conditions are caused by the defect in a receptor or receptor signalling pathway. Complete the table with either the name of the affected receptor or the name of the disease. (2.5 marks) Disease Familial Hypocalciuric Hypercalcemia Resistant Ovary Syndrome Vitamin D receptor PTH receptor Testicular Feminization Syndrome Receptor

2. Dynamic tests are used in the diagnosis of endocrine diseases. Complete the table with either the name of the disease or the corresponding dynamic test. Also fill in the biochemical marker(s) which should be measured for each test. (5.5 marks)

Disease Acromegaly Diabetes Mellitus Secondary hypothyroidism Kallmann’s Syndrome

Dynamic test

Biochemical marker(s)

FSH/LH Dexamethasone suppression test ACTH stimulation test

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3. What are the representative levels of the listed biochemical markers in chronic renal failure patient? Write INCREASED, DECREASED or NORMAL in the blank space beside each marker. (2 marks) Biochemical marker Level in chronic renal failure (Increased / Decreased / Normal) -----------------------------------------------------------------------------------------------------------------

PTH Phosphate GFR Blood Pressure

4. A 70 year-old woman attended her physician complaining of generalized bone pain and tetany. She had been diagnosed with liver cirrhosis five years ago and her condition was poorly controlled. Which of the following serum biochemistry result(s) is/are likely consistent with her condition? Fill in TRUE or FALSE in the blank space beside the result. (2 marks) Test Result Ca: 2.80 mmol/L (Normal 2.2 – 2.6) PTH: 0.6 pmol/L (Normal 1.3 – 7.6) 25(OH) vitamin D: 15 nmol/L (deficiency level