A 48-year-old man complaining of chest pain is brought to the emergency room. Physical examination followed by echocardiography demonstrates aortic stenosis. His coronary blood flow is increased. Which of the following is the most likely explanation for the increased coronary blood flow in this individual?
A 45-year-old man presents to the emergency department with severe headache and vomiting. A CT scan shows a well-circumscribed cystic lesion within the 3rd ventricle; there is no calcium deposition. The cyst is surgically removed. On histologic examination, the wall of the cyst consists of a single layer of mucin-producing columnar epithelium with a ciliated apical surface. Which of the following is the most likely diagnosis?
A 36-year-old female is brought to the emergency room by her husband who says that she 'complained of a severe headache then lost consciousness.' She has a history of hypertension and had been on several different medications. The examining physician notes that she is unable to move her arms and legs, but can blink her eyes. When the physician asks her to blink twice if she can hear him, she promptly does so. In which of the following structures is this woman's lesion most likely located?
A child develops a tumor of the cerebellum. Biopsy reveals evidence of both neuronal and glial differentiation. Which of the following is the most likely diagnosis?
Which of the following complications is currently the major limitation to the long-term success of cardiac transplantation?
A 56-year-old man visits his physician with complaints of complete exhaustion after mowing the lawn in his small front yard. He also complains of dizziness, irritability, difficulty sleeping, and loss of libido. On physical examination, the man's skin, conjunctiva, and oral mucosa are pale. A blood test indicates the man's hemoglobin is 7 g/dL. Which of the following findings is also likely to be present in this man?
An 8-month-old female child is brought to medical attention because her first four teeth show several discrete, discolored, circumferential bands that show very little enamel. Excessive levels of which of the following may have produced this defect?
A 2-year-old retarded child is evaluated by a metabolic specialist. The child's history is significant for failure to thrive and progressive neurologic deterioration, including deafness and blindness.
An increase in which of the following best explains the mechanism by which the cardiac output increases in severe anemia?
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