If you have not taken Form 4, please do not read this thread, you will lose the ability to assess your progress when you take it.
Please post an answer and the explanation. Thanks so much.
A 72-year-old man comes to the emergency department because of a 2-hour episode of loss of vision in the left eye. He has never smoked. Laboratory studies show:
Mean corpuscular volume
Which of the following is the most appropriate initial therapy?
A)Administration of allopurinol
B)Administration of aspirin
C)Administration of chlorambucil
D)Administration of hydroxyurea
E)Administration of warfarin
A 45-year-old man has had four episodes of involuntary twitching of the right foot. Following the last episodes, he had a tonic-clonic seizure. Which of the following structures on the left is the most likely origin of the seizure?
A)Inferior frontal cortex
B)Inferior temporal cortex
D)Primary motor cortex
E)Supplementary motor cortex
A 77-year-old man has had repeated episodes of difficulty speaking, facial numbness, and clumsiness of the left hand. Doppler ultrasonography of his carotid arteries shows no abnormalities. Which of the following drugs is the most appropriate therapy to prevent future episodes?
A 23-year-old woman has skin blistering that results from a point mutation in a single gene. Epidermal cells in these patients become fragile and rupture. Which of the following is the most likely effect of the genetic mutation?
A)Defective transport of vesicles from the centrosome to the cell membrane
B)Disrupted assembly of keratin into intermediate filaments
C)Lack of GTP required to form polymers of tubulin
D)Phosphorylation of actin monomers to promote polymerization
A 75-year-old man has a painless mass in the left upper anterior neck. Examination of tissue obtained on biopsy shows partial replacement of a lymph node by a neoplasm; the neoplasm is composed of cohesive sheets of polygonal cells with granular eosinophilic cytoplasm, prominent intercellular bridges, and pleomorphic round nuclei. Immunocytochemical preparations show a strongly positive reaction of the neoplastic cells to a high-molecular-weight keratin antibody. There is no reaction to antibodies against vimentin and leukocyte common antigen (CD45). Which of the following is the most likely diagnosis?
E)Squamous cell carcinoma
A 78-year-old man comes to the physician because of progressive swelling of the right side of his face and neck and his right upper extremity. His right jugular vein is engorged. Which of the following diagnoses is most likely to be confirmed on an x-ray of the chest?
A)Aortic arch aneurysm
B)Mass in the upper lobe of the right lung
CRight cervical rib
E)Thoracic duct blockage in the posterior mediastinum
A 28-year-old woman with AIDS has chronic diarrhea of unknown origin. After the failure of typical treatment approaches, subcutaneous injections of octreotide are begun. Which of the following best describes the therapeutic benefit of this structure analogy of somatostatin as compared with native somatostatin?
A)Decreased lipid solubility
B)Decreased volume of distribution
C)Delayed onset of action
E)Prolonged duration of action
A 54-year-old man is brought to the emergency department because of a 2-week history of progressive shortness of breath with exertion and leg swelling. He now requires two pillows for sleeping because of shortness of breath when lying flat. He has had a 4.5-kg (10-lb) weight gain during this period. He has a 15-year history of type 2 diabetes mellitus and hypertension that are poorly controlled despite treatment with a variety of medications. Two months ago, he began receiving a new diabetic medication that has been titrated upward during the past month. Crackles are heard at the lung bases bilaterally. Cardiac examination shows an S3 gallop. There is 2+ peripheral edema of the lower extremities. Which of the following medications is the most likely cause of the new symptoms in this patient?
Two hours after the onset of chest pain, a 48-year-old man comes to the emergency department. An ECG indicates acute myocardial ischemia. He receives tissue plasminogen activator as thrombolytic therapy. Which of the following adverse effects is most likely?
A)Acute allergic reaction
A 26-year-old woman with stable asthma wheezes when exposed to cats. Which of the following is the most appropriate prophylactic therapy?
The largest proportional increase in left ventricular afterload and myocardial oxygen consumption is most likely to occur following a 20% increase in which of the following?
B)Coronary blood flow
D)Right atrial pressure
A previously healthy 63-year-old man comes to the physician because of difficulty starting urination, decreased force and size of the urine stream, and dribbling when he tries to stop urinating. Cystoscopy shows hypertrophy and thickening of the bladder wall and dilation of the ureters. If untreated, which of the following sequelae is most likely?
A)Renal papillary necrosis
C)Transitional cell carcinoma of the bladder
E)Urinary tract infection
Which of the following is the role of iodine in the biosynthesis of thyroxine (T4)?
A)It activates a membrane transporter that increases the import of tyrosine
B)It is added to tyrosine residues in thyroglobulin in the first step of T4 biosynthesis
C)It is covalently bound to free tyrosine to form T4
D)It is an essential cofactor for thyroperoxidase
An otherwise healthy 80-year-old man is scheduled for endoscopy for evaluation of rectal bleeding. A standard dose of midazolam is administered intravenously when the patient is admitted to the endoscopy suite. A few minutes later, he develops cyanosis and labored respirations and requires ventilation with an oxygenated resuscitation bag. An age-related increase in which of the following is the most likely cause of these adverse effects?
C)Plasma protein binding
D)Sensitivity to sedatives
E)Volume of distribution
A 16-year-old girl is febrile and incoherent but able to indicate that she has severe lower abdominal pain. Pelvic examination shows a foul-smelling cervicovaginal discharge, and a septic abortion is suspected. Which of the following procedures is most appropriate for identifying the microbial agents causing her infection?
A)Inoculation of anaerobic transport media at the bedside
B)Inoculation of the specimen into tissue culture
C)Quantitation of the bacteria in the discharge by using a calibrated inoculating loop
D)Streaking a swab specimen onto Thayer-Martin media at the bedside
E)Use of Löwenstein-Jensen and Sabouraud media for acid-fast bacteria and fungi, respectively
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
A 6-year-old girl who is recovering from a severe "strep" throat is brought to the physician because her urine has had a "smoky" appearance several times in the past week. Urinalysis shows trace amounts of blood and protein. Which of the following cell types initiates the repair mechanism necessary to resolve the proteinuria and hematuria?
F)Proximal tubule epithelial cells
Triiodothyronine (T3) is more potent than thyroxine (T4) for the treatment of hypothyroidism because of which of the following?
A)Active transport into target cells
B)Greater accumulation in mitochondria
C)Greater receptor affinity
D)Higher oral bioavailability
E)Longer plasma half-life