07-22-2009, 07:50 AM
15. A dilute disinfectant kills 90% of a bacterial inoculum in 10 minutes. Which of the following is the shortest amount of time (in minutes) required to reduce an inoculum of 109 bacteria to less than 10 bacteria?
A) 10
B) 50
C) 100
D) 140
E) 180
NBME FORUM ;4
5. A 44-year-old man is brought to the emergency department because of a 5-hour history of severe epigastric pain that radiates to his back. He drank approximately twelve 12-ounce cans of beer before his pain began. Abdominal examination shows distention with generalized tenderness and no masses. His serum amylase activity is 500 U/L, and serum lipase activity is 325 U/L (N=14“280). Which of the following types of necrosis is most likely in this patient's retroperitoneum?
A) Caseous
B) Coagulative
C) Fat
D) Fibrinoid
E) Liquefactive
NBME FORM: 4
16. A 42-year-old man has a temperature of 39.2°C (102.6°F) and mild jaundice 2 days after transfusion of packed red cells for the treatment of chronic anemia. Laboratory studies show hyperbilirubinemia and a mild increase in serum lactate dehydrogenase activity. Which of the following findings will most likely be observed on analysis of peripheral blood cells?
A) Complement protein C3bi bound to monocytes
B) Degranulated neutrophils
C) Erythrocyte ghosts
D) HLA-DR upregulation in circulating CD3+ T lymphocytes
E) Immunoglobulin bound to erythrocytes
F) Nucleated erythrocytes
17. A screening test for colon cancer is administered to 1000 people with biopsy-proven colon cancer and to 1000 people without colon cancer. The test results are positive for 250 of the proven cases and 100 of those without colon cancer. The screening test is now to be used on a population of 100,000 people with a known prevalence rate of colon cancer of 80 per 100,000. Which of the following is the expected number of true positives and false positives in this population of 100,000 people?
True Positive False Positive
A) 20 9992
B) 20 89,928
C) 40 9992
D) 50 89,928
E) 60 9992
F) 60 89,928
G) 80 9992
H) 80 89,928
32. A 34-year-old woman is brought to the emergency department after she collapsed when she returned from a nonstop flight from New Delhi to New York City. She has smoked 1 pack of cigarettes daily for 16 years. She is sexually active and uses an oral contraceptive. Her pulse is 125/min, and blood pressure is 75/50 mm Hg. Physical examination shows jugular venous distention. The lungs are clear to auscultation. Pulmonary artery catheterization shows a pulmonary systolic/diastolic arterial pressure of 50/25 mm Hg (N=15“30/3“12) and a pulmonary artery wedge pressure of 5 mm Hg (N=8“16). Which of the following is the most likely cause of her pulmonary hypertension?
A) Decreased cardiac output
B) Increased left atrial pressure
C) Increased left ventricular diastolic pressure
D) Increased pulmonary blood flow
E) Increased pulmonary venous resistance
F) Occlusion of left ventricular outflow tract
G) Occlusion of pulmonary arteries
H) Pericardial tamponade
A) 10
B) 50
C) 100
D) 140
E) 180
NBME FORUM ;4
5. A 44-year-old man is brought to the emergency department because of a 5-hour history of severe epigastric pain that radiates to his back. He drank approximately twelve 12-ounce cans of beer before his pain began. Abdominal examination shows distention with generalized tenderness and no masses. His serum amylase activity is 500 U/L, and serum lipase activity is 325 U/L (N=14“280). Which of the following types of necrosis is most likely in this patient's retroperitoneum?
A) Caseous
B) Coagulative
C) Fat
D) Fibrinoid
E) Liquefactive
NBME FORM: 4
16. A 42-year-old man has a temperature of 39.2°C (102.6°F) and mild jaundice 2 days after transfusion of packed red cells for the treatment of chronic anemia. Laboratory studies show hyperbilirubinemia and a mild increase in serum lactate dehydrogenase activity. Which of the following findings will most likely be observed on analysis of peripheral blood cells?
A) Complement protein C3bi bound to monocytes
B) Degranulated neutrophils
C) Erythrocyte ghosts
D) HLA-DR upregulation in circulating CD3+ T lymphocytes
E) Immunoglobulin bound to erythrocytes
F) Nucleated erythrocytes
17. A screening test for colon cancer is administered to 1000 people with biopsy-proven colon cancer and to 1000 people without colon cancer. The test results are positive for 250 of the proven cases and 100 of those without colon cancer. The screening test is now to be used on a population of 100,000 people with a known prevalence rate of colon cancer of 80 per 100,000. Which of the following is the expected number of true positives and false positives in this population of 100,000 people?
True Positive False Positive
A) 20 9992
B) 20 89,928
C) 40 9992
D) 50 89,928
E) 60 9992
F) 60 89,928
G) 80 9992
H) 80 89,928
32. A 34-year-old woman is brought to the emergency department after she collapsed when she returned from a nonstop flight from New Delhi to New York City. She has smoked 1 pack of cigarettes daily for 16 years. She is sexually active and uses an oral contraceptive. Her pulse is 125/min, and blood pressure is 75/50 mm Hg. Physical examination shows jugular venous distention. The lungs are clear to auscultation. Pulmonary artery catheterization shows a pulmonary systolic/diastolic arterial pressure of 50/25 mm Hg (N=15“30/3“12) and a pulmonary artery wedge pressure of 5 mm Hg (N=8“16). Which of the following is the most likely cause of her pulmonary hypertension?
A) Decreased cardiac output
B) Increased left atrial pressure
C) Increased left ventricular diastolic pressure
D) Increased pulmonary blood flow
E) Increased pulmonary venous resistance
F) Occlusion of left ventricular outflow tract
G) Occlusion of pulmonary arteries
H) Pericardial tamponade