1. A spontaneous mutation in a culture of lymphocytes produces an inactive form of caspase-9. Which of the following is most likely occur in these lymphocytes?

O A) Continuous proliferation O B) Phagocytosis by neighboring cells O C) Release of intracellular contents O D) Release of toxic oxygen radicals into the extracellular space

2. A 44-year-old man with HIV infection comes to the physician because of a 3-week history of progressive watery diarrhea. His temperature is 35.9°C (96.6°F), pulse is 88/min when supine and 110/min when standing, respirations are 14/min, and blood pressure is 108/70 mm Hg when supine and 96/60 mm Hg when standing. Physical examination shows dry mucous membranes and no abdominal tenderness. His CD4+ T-lymphocyte count is less than 20/mm3 (N>500). Microscopic examination of a concentrated stool specimen stained with a modified acid-fast staining method shows multiple organisms. Which of the following is the most likely causal organism?

O A) Cryptosporidium parvum O B) Entamoeba histolytica O C) Giardia lamblia O D) Mycobacterium tuberculosis O E) Strongyloides stercoralis

3. Transgenic mice are generated that are incapable of expressing pj-microglobulin. Which of the following components of host defense is most likely to be altered in these mice?

O A) Complement O B ) CytotoxicTlymphocytes O C) lnterleukin-2 (IL-2) secretion O D) Natural killer cells O E) Neutrophils

4. A 35-year-old man Is brought to the emergency department 1 hour after he sustained a fracture of his left radius in a fall. He has end- stage renal disease and has been receiving hemodialysis for 10 years. An x-ray of the left upper extremity shows osteopenia. The most likely cause of the osteopenia is decreased synthesis and secretion of which of the following substances?

O A) CalcitoninO B) 1,25-Dihydroxycholecalciferol O C) Erythropoietin O D) Parathyroid hormone O E) Renin

5. A 36-year-old woman is brought to the emergency department by her husband because of a 3-day history of fever and increasing confusion. She is awake but slow to respond. Her temperature is 38.4°C (101.1°F). Physical and neurologic examinations show no other abnormalities. Examination of cerebrospinal fluid (CSF) obtained on lumbar puncture shows:

Pressure, opening normalAppearance clearGlucose 65 mg/dLProtein, total 85 mg/dLLeukocyte count 110/mm3

Lymphocytes 98%Erythrocyte count 3/mm3

A Gram stain of CSF shows no bacteria. A CT scan of the head shows an enhancing lesion within the right temporal lobe. Which of the following tests is most appropriate to confirm the diagnosis?

Diagnostic Test VirusO A) CSF antibody La CrosseO B) CSF culture herpes simplex© C) CSF culture La CrosseO D) CSF culture poliovirusO E) CSF polymerase chain reaction herpes simplex O F) Stool culture poliovirus

6. A 47-year-old man comes to the emergency department because of a 2-hour history of vomiting bright red blood. He has a 20-year history of alcoholism. Physical examination shows jaundice and scleral icterus. Endoscopy shows esophageal bleeding from the mucosa. The most likely cause of the bleeding is an indirect shunting of portal blood to the superior vena cava via which of the following veins?

O A) HepaticO B) Inferior mesentericO C) Left gastricO D) Right gastroepiploicO E) SplenicO F) Superior mesenteric

7. A 32-year-old man is brought to the emergency department 20 minutes after having a generalized tonic-clonic seizure. He has a 24-hour history of fever, headache, and intolerance of light. He is alert. His temperature is 40°C (104°F), pulse is 140/min, respirations are 24/min, and blood pressure is 90/55 mm Hg. He appears acutely ill. Neurologic examination shows no focal findings. Intravenous fluids are administered, and there is persistent bleeding around the intravenous site. Laboratory studies show:

Prothrombin time 16 sec (INR=1.1)Partial thromboplastin time 33 secFibrin degradation products increased

Which of the following changes is most likely in the blood coagulation process of this patient?

O A) Decreased fibrinolysis O B) Decreased microvascular thrombus formation O C) Decreased thrombin production O D) Increased circulating clotting factors O E) Increased plasmin generation O F) Increased platelet count

A 56-year-old man who is right-handed comes to the physician because of a 2-month history of progressive clumsiness in the right hand and difficulty finding words. Neurologic examination shows upper motoneuron weakness of the right upper extremity, and difficulty with naming and repetition. An MRI of the brain shows an infiltrating left frontal mass. Analysis of a stereotaxic biopsy specimen shows a grade II astrocytoma. Impaired activity of which of the following proteins is the most likely cause of this lesion?

9. A 74-year-old man undergoes surgical repair of an abdominal aortic aneurysm. During surgery he receives 1 liter loses. This volume of fluid excess is most likely to cause an acute decrease in which of the following hormones?

O A) Angiotensin II O B ) Atrial natriuretic peptide O C) Erythropoietin O D) Testosterone O E) Thyroxine (TJ

Lab Values F

10. A 5-year-old girl is brought to the physician by her parents for an initial physical examination. They recently moved to town, and they failed to bring any medical records. They state that the child was "behind" in most of her developmental milestones, and that her teeth erupted "late." During the last 3 years, she has sustained fractures of both upper extremities as well as her left lower extremity. The physician notes a distinct nasal quality to the child's voice. Her height is at the 10th percentile, and her weight is at the 30th percentile. Physical examination shows frontal bossing of the skull. X-rays confirm the healed fractures and show generalized increase in bone density, and widening of the metaphyses and diaphyses of the long bones. Which of the following are most likely to be defective in this patient?

O A) Chondroblasts O B) Chondrocytes O C) Myocytes O D) Osteoblasts O E) Osteoclasts O F) Osteocytes

11. A 45-year-old man is brought to the emergency department 1 hour after ingesting a near-lethal dose of phenobarbital. He is not responsive to painful stimuli, and his respirations are 5/min. Respiratory parameters of a healthy adult residing at sea level and breathing room air are represented by points X and T in the graphs shown. Which of the following two points most likely represent the respiratory parameters of this patient?

O A) X and T O B) Y and T O C) Y and V O D) Y and W O E) Z and T O F) Z and V O G) Z and W

12. A 68-year-old man comes to the physician because of a 6-week history of fatigue, difficulty concentrating, increased appetite, and an increased need for sleep; he has had a 2.3-kg (6-lb) weight gain during this period. He reports missing several days of work and not attending church during the past 3 weeks because he has been tired. He has a 10-year history of type 2 diabetes mellitus well controlled with diet and glyburide therapy. Over the past 2 years, his blood glucose concentrations by fingerstick and hemoglobin A 1c had been within the reference ranges. He drinks 1 to 2 beers on the weekends and does not use illicit drugs. Physical and neurologic examinations show no changes from his last visit. He makes poor eye contact and has a restricted affect. His serum glucose concentration is 220 mg/dL, and hemoglobin A1c is 10.6%. Otherwise, his complete blood count and metabolic profile (SMA-21) are within the reference range. Which of the following is the most likely cause of this patient's current lack of glycemic control?

O A) Adjustment reaction with depressed mood O B) DeliriumO C) Dementia, Alzheimer type O D) Major depressive disorder O E) Multi-infarct (vascular) dementia O F) Schizophrenia O G) Sleep apnea

13. A male newborn born at 30 weeks' gestation is admitted to the neonatal intensive care unit. His grandmother insists that the child given chamomile tea to treat his complications of prematurity. She gets agitated when the nursing staff tries to assure her that he being cared for appropriately. She requests that her grandson be transferred to another physician at another hospital. At the grandmother's insistence, she and the child's mother meet with the physician to discuss the grandmother's requests. After the physician listens to the grandmother's reason for wanting to use the tea, which of the following approaches is most appropriate?

O A) Explain that the tea will increase the child's risk for developing sloughing of the gastrointestinal mucosaO B) Gain the grandmother's support by acknowledging that she probably knows best and tell her that the tea will be

administered, but fail to do soO C) Inform the mother and the grandmother of the physician's credentials to assure them that the child is getting the best care

possibleO D) Negotiate a plan to give the tea when the child's gastrointestinal tract will allow administration of liquids

Lab Values F

14 A 69-year-old man is brought to the physician because of a 2-day history of pain of his right knee. During the past 3 years, he also has had recurrent episodes of pain of the left great toe and one episode of pain and swelling of the left elbow. These episodes improved following use of over-the-counter ibuprofen. He has hypertension, gastroesophageal reflux disease, and hypercholesterolemia. Current medications include hydrochlorothiazide, ranitidine, and atorvastatin. Physical examination shows erythema and warmth over the right knee. Nodules are present on the helix of the left ear, chin, right shoulder, middle back, and lower back. Which of the following nodules is most likely a tophus?

O A) Chin O B) Ear O C) Lower back O D) Middle back O E) Shoulder

15. A 3-year-old boy with sickle cell disease is brought to the emergency department because of severe leg pain for 2 hours. Physical examination shows hepatosplenomegaly and tenderness over the lower extremities. His hemoglobin concentration is 7 g/dL. A peripheral blood smear shows target cells, poikilocytes, and many sickled erythrocytes. Which of the following best describes the molecular basis for sickling in this patient?

O A) Gain of stabilizing hydrophobic interactions in the deoxygenated form of hemoglobin S O B) Gain of stabilizing hydrophobic interactions in the oxygenated form of hemoglobin S O C) Loss of stabilizing hydrogen bonds between water and the surface of hemoglobin S in the oxygenated state O D) Loss of stabilizing salt bridges in the deoxygenated form of hemoglobin S O E) Loss of stabilizing salt bridges in the oxygenated form of hemoglobin S

16. A 68-year-old woman comes to the physician because of visual problems for the past 2 weeks. Examination shows left homonymous hemianopia. Which of the following labeled structures in the MRI of the brain is most likely involved?

A

17. A 25-year-old man comes to the physician for an examination prior to starting a new job at a software company. He has been terminated from similar positions in the past because of his inability to work on group projects, lack of insight into his performance, and indifference to feedback from his supervisors. He has no history of major medical illness. He has few close relationships and spends most of his time at home working on computer programming activities. Physical examination shows no abnormalities. Mental status examination shows no abnormalities of thought, perception, or affect. This patient most likely has which of the following types of personality disorders?

O A) Antisocial O B) Borderline O C) Dependent O D) Narcissistic O E) Schizoid

18. A healthy 21 -year-old man is undergoing initial screening for intestinal polyps. Sigmoidoscopy shows multiple sessile andpedunculated polyps throughout the rectum and sigmoid colon. Physical examination shows poor dentition and several osteomas the mandible and skull. Which of the following is the most likely diagnosis?

O A) Cowden disease O B) Cronkhite-Canada syndrome O C) Gardner syndrome O D) Inflammatory mucosal polyps O E) Juvenile polyposis O F) Peutz-Jeghers syndrome

Lab Values F

19. A 42-year-old woman has the sudden onset of abdominal pain 1 day after undergoing abdominal hysterectomy because of leiomyomata uteri. Her temperature is 38.3°C (101°F). Abdominal examination shows tenderness over the right lower quadrant. Retrograde pyelography shows contrast in the left renal pelvis and none in the right renal pelvis. A structure that passes inferior to which of the following was most likely severed during the operation?

O A) Ovarian artery O B) Ovarian ligament O C) Mesosalpinx O D) Round ligament of the uterus

20. A 65-year-old man comes to the physician because of pain with urination and episodes of blood in his urine during the past 3 months. Physical examination shows no abnormalities. Cytologic examination of the urine shows transitional cell carcinoma. Which of the following findings on a biopsy of the urinary bladder is the strongest indication for cystectomy in this patient?

O A) Multifocal transitional cell carcinoma in situ O B) Noninvasive high-grade papillary transitional cell carcinomaO C) Noninvasive low-grade transitional cell carcinoma with focal transitional cell carcinoma in situ O D) Papillary transitional cell carcinoma with invasion into detrusor muscle O E) Papillary transitional cell carcinoma with more than 10 mitotic figures per 10 high-power fields

21. A 25-year-old man is brought to the emergency department because of confusion and stupor for 1 hour. He is a nurse. This is his fourth similar episode within the past 4 months; he is asymptomatic between the episodes, which are not related to meals. Physical examination shows no abnormalities. Laboratory studies show a serum glucose concentration of 30 mg/dL. Serum glucose concentrations during his previous episodes have ranged from 20 mg/dL to 40 mg/dL. Dextrose resolved the symptoms during his previous visits. In addition to stabilizing the patient, which of the following is the most appropriate next step in establishing a diagnosis?

O A) 24-Hour urine collection for measurement of ACTH O B) Measurement of serum C-peptide concentration O C) Measurement of serum cortisol concentration O D) CT scan of the pancreas O E) Prednisone therapy

22. A 45-year-old man who works at a nuclear power plant is brought to the emergency department 1 hour following an accident in which he was exposed to high levels of radiation. The amount of exposure is not believed to be fatal. He appears agitated and fearful, but he currently has no symptoms. This patient is most likely to initially show which of the following types of symptoms?

O A) Cardiovascular O B) Gastrointestinal O C) Renal O D) Reproductive O E) Respiratory

23. A 31-year-old woman has her pituitary stalk inadvertently transected during an operation to remove a tumor adjacentto thehypothalamic area. Secretion of which of the following pituitary hormones is most likely to be increased in this patient as a result of the transection?

O A) ACTH O B) Growth hormone O C) Luteinizing hormone O D) ProlactinO E) Thyroid-stimulating hormone

A study is conducted to estimate the number of procedures performed by general internal medicine physicians. A questionnaire is mailed to 8000 randomly selected physicians. Of these, 5680 (71%) respond. Which of the following measurements most strongly suggests that the respondents represent a heterogeneous population with respect to the number of different procedures performed?

Mean Number of Procedures Performed Standard Deviation

25. Shining a light in either eye causes constriction of the pupil in the same eye (direct light reflex) and also in the contralateral eye (consensual light reflex). This clinical maneuver is a test of the functional integrity of which of the following areas of the nervous system?

O A) Medulla O B) Midbrain O C) PonsO D) Superior cervical ganglion O E) Visual cortex

26. A 26-year-old woman comes to the emergency department 2 hours after the acute onset of fever, chest pain, and shortness of breath. Echocardiography shows diffuse hypokinesis. A virus isolated from her pharynx is thought to be related to her heart disease. The virus is most likely which of the following?

O A) Coxsackievirus O B) Epstein-Barr virus O C) Herpes simplex virus O D) Measles virus O E) Parainfluenza virus

26. A 26-year-old woman comes to the emergency department 2 hours after the acute onset of fever, chest pain, and shortness of breath. Echocardiography shows diffuse hypokinesis. A virus isolated from her pharynx is thought to be related to her heart disease. The virus is most likely which of the following?

O A) Coxsackievirus O B) Epstein-Barr virus O C) Herpes simplex virus O D) Measles virus O E) Parainfluenza virus

27. A 30-year-old man with HIV infection comes to the physician because of a rash for 3 weeks. The rash is not pruritic or painful. He has not had fevers or chills, and there have been no recent changes in the soaps and detergents that he uses. He takes no medications. He does not smoke cigarettes or drink alcohol. His vital signs are within normal limits. Physical examination shows diffuse lesions on his chest, back, and arms similar to those shown in the photograph. There are no lesions on the palms or soles. Which of the following is the most likely diagnosis?

O A) Herpes simplex O B) Human papillomavirus infection O C) Kaposi sarcoma O D) Molluscum contagiosum O E) Rickettsia rickettsii infection O F) SyphilisO G) Varicella-zoster virus infection

27. A 30-year-old man with HIV infection comes to the physician because of a rash for 3 weeks. The rash is not pruritic or painful. He has not had fevers or chills, and there have been no recent changes in the soaps and detergents that he uses. He takes no medications. He does not smoke cigarettes or drink alcohol. His vital signs are within normal limits. Physical examination shows diffuse lesions on his chest, back, and arms similar to those shown in the photograph. There are no lesions on the palms or soles. Which of the following is the most likely diagnosis?

O A) Herpes simplex O B) Human papillomavirus infection O C) Kaposi sarcoma O D) Molluscum contagiosum O E) Rickettsia rickettsii infection O F) SyphilisO G) Varicella-zoster virus infection

28. A 52-year-old woman dies 9 months after being diagnosed with well-differentiated ductal carcinoma of the right breast metastatic the brain, lung, and liver. Her mother and one of her sisters also have died of breast cancer. Which of the following molecular abnormalities is most likely to be found in this patient?

O A) Amplification of the HER2 gene in somatic cells O B) Amplification oftheN-myc gene in neoplastic cells O C) Deletion of the Rb locus in healthy somatic cells O D) Fusion of the BCR and C-ABL genes in neoplastic cells O E) Germline inactivation of the BRCA1 gene

29. A 50-year-old woman dies of a myocardial infarction. A photograph of the brain obtained at autopsy is shown; the arrows indicate an abnormality. Based on the image shown, which of the following findings was most likely present in this patient prior to her death?

O A) Decreased visual acuity O B) Difficulty swallowing O C) Double vision O D) Hearing loss O E) Loss of sense of smell

30. A 52-year-old woman comes to the physician because of nausea, intermittent bloating, and diarrhea for 5 days. She underwent; gastric bypass operation 1 month ago and has had a 9-kg (20-lb) weight loss since then. Abdominal examination shows mild distention. Which of the following is the most likely cause of this patient's symptoms?

O A) Absence of functional parasympathetic ganglia in the large bowel O B) Hypersecretion of acidO C) Rapid emptying of hyperosmolar chyme into the small bowel O D) Spasm of the pyloric sphincter O E) Surgical interruption of vagal fibers to the stomach

31. A 20-year-old woman is admitted to the hospital because of weakness of the legs, generalized severe abdominal pain, persistent vomiting, and port-wine-colored urine for 8 hours. She began taking an oral contraceptive 1 month ago. She has a history of three similar episodes for which she did not seek medical attention. Physical examination shows abdominal tenderness and guarding. There is weakness of the lower extremities and decreased muscle stretch reflexes. Urine studies are most likely to show an increased concentration of which of the following?

O A) Bilirubin O B) Cystine O C) Homogentisic acid O D) Porphobilinogen O E) Uric acid

32. A 45-year-old woman receives injections of botulinum toxin into the facial muscles surrounding her eyes to reduce wrinkles. This acts by interfering with which of the following mechanisms?

O A) Action of acetylcholinesterase in primary and secondary synaptic clefts O B) Binding of acetylcholine to postsynaptic receptors O C) Diffusion of acetylcholine across the synaptic cleft O D) Release of acetylcholine into the primary synaptic cleft O E) Release of Ca2* into the cytosol of the axon terminal

33. A 44-year-old man with invasive bladder cancer undergoes a neurosurgical procedure for the relief of severe low back and pelvic pain on the right. The most likely location of the lesion is at which of the following labeled sites in the cross section of a normal spinal cord?

O A) O B ) O C) O D) O E) O F )

34. A previously healthy 47-year-old woman comes to the physician because of a 3-week history of easy fatigability, proximal muscle weakness, pruritus, constipation, and lower abdominal pain. Her mother, who is still alive, had a tumor in her thyroid gland and another one in her adrenal gland surgically removed. The patient is found to have renal calculi and a parathyroid adenoma. Follow-up genetic testing is recommended. Which of the following genes should be tested?

O A ) BRCA1 O B) BRCA2 O C ) CFTRO D) p53 tumor suppressor gene O E) Ret

35. A previously healthy 42-year-old man comes to the physician because of fever, chills, and nonproductive cough for 3 days. He works in construction. His temperature is 39.5°C (103.1 °F). Bilateral inspiratory crackles and diffuse expiratory wheezing are heard on auscultation of the chest. Sputum cultures grow Legionella pneumophila. Once this organism establishes its presence in this patient's alveoli, which of the following mechanisms is most integral to clearing the organism from his alveoli?

O A) B-lymphocyte-mediated immunity O B) Complement-mediated lysis O C) Ingestion by type II pneumocytes O D) Mucociliary clearance O E) T-lymphocyte-mediated immunity

36. A 65-year-old woman comes to the clinic 8 weeks after she found a lump in her right breast on self-examination. Physical examination shows dimpling over the mass. Mammography of the breast shows a 4-cm mass in the lower lateral quadrant of the right breast. The dimpling of the skin is most likely due to traction of the tumor on which of the following structures?

O A) Branches of the cutaneous pectoral nerves O B) Lactiferous ducts O C) Mammary arteries and veins O D) Mammary lymphatics O E) Suspensory (Cooper) ligaments

37. A 19-year-old primigravid woman delivers a healthy male newborn at term. She asks if breast-feeding would be good for her baby. She is told that breast-feeding would result in passive transfer of her immunity to the baby. This would involve the movement of dimeric IgA molecules through polarized epithelial cells to reach the ductal lumen. Which of the following best describes this process?

O A) Endocytosis O B) Phagocystosis O C) Pinocytosis O D) Sorting O E) Transcytosis

38. A 54-year-old man comes to the physician because of a 2-week history of numbness of his hands and feet. He began a course of daily treatment with isoniazid 6 months ago after the result of a PPD skin test was positive. Physical examination and a chest x-ray at that time showed no abnormalities. Physical examination at this visit shows sensation to pinprick that is decreased in the extremities. Which of the following is the most appropriate pharmacotherapy for this patient?

O A) NiacinO B) Vitamin B, (thiamine)O C) Vitamin B2 (riboflavin)O D) Vitamin B6(pyridoxine)O E) Vitamin B12(cyanocobalamin)

I. During an experiment, the following data are obtained from an anesthetized dog: Mean glomerular capillary hydrostatic pressure (HPGC) Mean Bowman space hydrostatic pressure (HPBS) Mean glomerular capillary oncotic pressure (nGo) Mean Bowman space oncotic pressure (nBS) Coefficient of filtration (Kf)Renal blood flow Hematocrit Filtration fraction

0 minutes. Which of the following is most likely in this animal after the

O A) Increased filtration fraction O B) Increased HPBS O C) Increased Kf O D) Decreased mean nGC O E) Decreased renal blood flow

40. A 33-year-old woman with hypertension is treated with a calcium-channel blocker that is known to slow conduction through the atrioventricular node. Which of the following components of an ECG will be affected most by this drug?

O A) PR interval O B) QRS amplitude O C) QRS width O D) QT interval O E) Sinus rate

41. An unconscious 40-year-old woman is brought to the emergency department after taking an overdose of a drug. For which of the following drugs is a method for active removal from the blood available using an immunologic strategy?

O A) Chlorambucil O B) Digoxin O C) Parathion O D) Phenoxybenzamine O E) Tranylcypromine

42. A 70-year-old man comes to the emergency department because of shortness of breath for 2 hours. He had a myocardial infarction 2 years ago. A chest x-ray shows bilateral Kerley B lines and bilateral pleural effusions that are greater on the right. If a thoracentesis were done, laboratory studies would show:

Which of the following processes best explains the pleural fluid findings?

O A) Decreased vascular hydrostatic pressure O B) Decreased vascular oncotic pressure O C) Decreased vascular permeability O D) Increased vascular hydrostatic pressure O E) Increased vascular oncotic pressure O F) Increased vascular permeability

Serum total protein Pleural fluid

7 g/dL

Specific gravity Total protein

1.008 1 g/dL 500/mm: 0.2

Leukocyte countPleural fluid:plasma lactate dehydrogenase ratio

43. A 23-year-old woman comes to the physician because of a 1 -day history of fever, nausea, and vomiting. She also has a 4-day history of pain with urination and urinary urgency and frequency. She appears ill. Her temperature is 39°C (102.2°F), pulse is 125/min, and blood pressure is 96/60 mm Hg. Physical examination shows suprapubic and flank tenderness. Urinalysis shows 30 WBC/hpf. Which of the following best describes the virulence factor of the causal organism?

O A) Lipoteichoic acid O B) M protein O C) P pili O D) Protein F O E) Pyrogenic exotoxin

44. A 63-year-old man is brought to the emergency department 30 minutes after the sudden onset of constricting chest pain that radiates to his back and left shoulder. ECG confirms acute myocardial infarction. He dies 20 minutes later. Which of the following is most likely on light microscopic examination of the myocardium?

O A) Congested, dilated capillaries O B) Macrophage infiltration O C) Neutrophilic infiltration O D) Normal histologic findings O E) Nuclear pyknosis, karyolysis, and karyorrhexis

45. A 60-year-old man with a 10-year history of alcoholism is admitted to the hospital for treatment of acute esophageal bleeding. He is scheduled for an operation. In order to decrease the portal venous pressure to the esophageal veins, it is most beneficial to join the portal vein to which of the following veins?

O A) Gastroduodenal O B) Inferior vena cava O C) Left gastroepiploic O D) Splenic O E) Superior mesenteric

46. A study is conducted comparing British bus drivers, who remain seated while working, with bus conductors, who walk and climb steps to the second deck of the bus. The body weights of drivers and conductors are the same at the outset of the study, as judged by the size of their dispensed uniforms and belts. The two groups' weights are compared over a 20-year period. The study finds that bus drivers gain more weight and are more likely to have a myocardial infarction than bus conductors. Which of the following best describes the design of this study?

O A) Case-control O B) Case series O C) Cohort O D) Cross-sectional O E) Randomized clinical trial

47. A healthy 24-year-old man is participating in a study of swallowing. The manometric pressure changes that occur while this swallows are shown. Which of the following traces best represents muscle activity in the upper esophageal sphincter?

48. A 6-year-old girl has had recurrent life-threatening infections caused by coagulase-positive staphylococci since the age of 3 months. Her leukocyte count is 9500/mm3. Immunoglobulin concentrations are: IgA 200 mg/dL; IgG 1800 mg/dL; IgM 250 mg/dL. Which of the following tests will most likely establish the diagnosis?

O A) Determination of antibody titers to Staphylococcus aureus O B) Immunoelectrophoresis O C) NADPH oxidase test O D) Peripheral blood CD4+ T-lymphocyte count O E) Tuberculin and Candida skin tests

49. A 40-year-old man undergoes extensive skin grafting to the face after sustaining burns over 50% of his total body surface area. At the time of discharge, he refuses to leave the burn unit because "people will look at me funny." Which of the following best explains this response?

O A) Body dysmorphic disorder O B) Common concern of persons with facial burns O C) Ideas of reference O D) Narcissistic personality disorder O E) Oppositional defiant disorder

50. A 62-year-old man comes to the physician because of a 1 -year history of urinary hesitancy, decreased urinary stream, and frequent urination, especially at night. He feels that his bladder never fully empties. Physical examination shows diffuse enlargement of the prostate, with no tenderness. Urinalysis shows no protein, glucose, RBCs, or WBCs. His serum prostate-specific antigen concentration is 1.5 ng/mL (N<4). Which of the following is the most appropriate treatment?

O A) Restriction of dietary sodium intake O B) a-Adrenergic antagonist O C) Antibiotic with activity against gram-negative rods O D) Competitive inhibitor of prostate estrogen receptors O E) Diuretic acting at the loop of Henle