A 15-year-old boy is evaluated by a clinician for failure to develop normal male secondary sexual characteristics. Physical examination reveals small testes, a small penis, and gynecomastia. The boy has had some difficulties in school, and the parents say that the school psychometrist said he had an IQ of 90. This patient's condition is most likely to be related to which of the following?
A young man recently died during surgery
under general anesthesia. Symptoms prior to his death included muscle spasms,
hyperthermia, acidosis, and cardiac arrest. His family history is significant
for his father dying under similar conditions and an aunt having survived the
same complications during a hip replacement surgery. He is survived by his
wife, a son, and a daughter. DNA has been isolated from family members and a
Southern blot of restriction fragments from a specific region of chromosome
19 reveals the following pattern: Which of the following conclusions can
reasonably be drawn from these data?
A 14-year-old boy has just moved with his family from Brazil to the U.S. He starts complaining of shortness of breath and palpitations. Chest x-ray films demonstrate pulmonary congestion, and ECG shows alterations in heart rhythm. Echocardiography reveals biventricular dilatation with massive cardiac enlargement. An endomyocardial biopsy shows diffuse interstitial fibrosis, myocyte necrosis, chronic inflammation, and the presence of intracellular protozoan parasites. The patient may also develop which of the following complications?
A 25-year-old man presents with a chief complaint of persistent, high-pitched ringing noises in his ears. Questioning reveals that he has also been losing his balance lately. CT of the head demonstrates bilateral tumors involving the vestibulocochlear nerve. Which of the following chromosomes contains the tumor suppressor gene most likely to be involved in this case?
A 14-year-old patient is brought in by his parents because of a sore throat. On physical examination, he is febrile, and has pharyngeal erythema with a tonsillar abscess. A throat culture on sheep blood agar yields colonies of gram-positive cocci that are surrounded by a zone of complete hemolysis. The organism was also plated on mannitol salt agar; it grew well and caused the medium to turn yellow. Which of the following microorganisms is the most likely cause of the patient's illness?
A patient with rheumatoid arthritis mentions to her physician that after many years without dental problems, she has recently had seven dental caries filled. This finding suggests that she should be evaluated for which of the following diseases?
Which of the following hormones is secreted by anterior pituitary cells
During embryological development, hematopoiesis occurs in different organs at different times. Which of the following are the correct organs, in the correct sequence, at which hematopoiesis occurs embryologically?
Evaluation of an infant with a variety of congenital abnormalities reveals hypocalcemia due to a lack of parathyroid hormone. On x-ray, the thymic shadow is absent. A failure of development and differentiation of which of the following embryonic structures would most likely be responsible for the observed presentation?
An endocrinologist examines a patient suspected of having Riedel thyroiditis. Which of the following findings on physical examination would best help confirm the diagnosis?