A healthy 42-year-old woman with a history of anxiety attacks sits in the hospital waiting room as her 3-year-old daughter undergoes open heart surgery for a septal malformation. The woman experiences a feeling of suffocation and is obviously hyperventilating. She informs her husband that she feels faint and has blurred vision. Which of the following is most likely to relieve the symptoms caused by hyperventilation?
A patient, who appears to be female, is found to be 46,XY. The patient's vagina is very shallow, ending in a blind pouch, and there are palpable masses in the labia. The diagnosis of testicular feminization syndrome is made. Which of the following was most likely present during the early fetal life of this individual?
Which of the following would be expected to be decreased in a patient with chronic hypertension secondary to renal artery stenosis?
A surgeon performs an exploratory laparotomy, producing a large incision in the patient's abdomen. Poor blood supply to which of the following is most likely to cause problems during the healing process?
A premature infant develops progressive difficulty breathing over the first few days of life. Deficient surfactant synthesis by which of the following cell types may have contributed to the baby's respiratory problems?
During development, the formation of the kidney is induced by which of the following structures?
A 40-year-old woman presents to the emergency department because of hematuria. Laboratory analyses show significant proteinuria, bacteria and white cells in the urine, and a blood urea nitrogen (BUN) of 40 mg/dL with a creatinine of 4.0 mg/dL. Ultrasonography reveals enlarged kidneys, and she is given a provisional diagnosis of polycystic renal disease. Which of the following is likely to be decreased in this patient?
A 30-year-old pregnant woman of Jewish descent presents to a physician with painful oral ulcers. Physical examination demonstrates widespread erosions of her mucous membranes. Close examination reveals a friable mucosa, but no well-defined aphthous ulcers. Biopsy of perilesional mucosa demonstrates acantholysis; direct immunofluorescence demonstrates an intraepidermal band of IgG and C3. Which of the following is the most likely diagnosis?
An experimental serologic test is
developed to detect the presence of HIV antibody. Epidemiological analysis
reveals the results shown below. What is the sensitivity of this test?
A 60-year-old alcoholic smoker abruptly develops high fever, shakes, a severe headache, and muscle pain. He initially has a dry, insignificant cough, but over the next few days he develops marked shortness of breath requiring assisted ventilation. Chest x-ray demonstrates homogeneous radiographic shadowing that initially involves the left lower lobe but continues to spread until both lungs are extensively involved. Culture of bronchoalveolar lavage fluid on buffered charcoal yeast extract (BCYE) demonstrates a coccobacillary pathogen. Which of the following is the most likely causative organism?