Microsoft word - 2008gsi.s1.doc

SAMPLE ITEMS
BLOCK 1, ITEMS 1-50
A healthy 25-year-old man is undergoing an An otherwise healthy 3-week-old boy is brought exercise stress test. Which of the following is to the physician's office because of jaundice and most likely to occur in this man's skeletal muscle hepatomegaly, and his stools are loose, clay-colored, and acholic. Serum conjugated bilirubin (A) Decreased capillary hydrostatic pressure concentration is increased. Which of the following is the most likely cause of the (D) Increased oxygen concentration (E) Increased (B) Deficiency of glucuronosyltransferase (C) Hemolysis A 16-year-old boy has a 1-day history of pain in the right ear. He swims every morning. The right ear canal is red and swollen. He has pain when the auricle is pulled or the tragus is pushed. Which of the following is the most likely A man pushes a piano across the floor. At the wrist, the force is transmitted from the carpal bones to the radius. At the elbow, the force is transmitted from the ulna to the humerus. Which of the following structures transmits the force (A) Annular ligament (B) Bicipital aponeurosis (C) Flexor retinaculum (D) Intermuscular septum (E) Interosseous A normal peptide has 100 amino acids. Following mutation, it has only 20; 1–10 are the same as the normal peptide; 11–20 differ from the normal peptide. Which of the following (A) Nucleotide deletion in the codon for (B) Nucleotide deletion in codon 20 (C) Nucleotide deletion in the intervening The control curve shown in the graph illustrates the relationship between the initial velocity of a reaction and the substrate concentration for any enzyme obeying Michaelis-Menten kinetics. Which of the following is used as a metabolic Which of the following curves best represents energy source by erythrocytes after an overnight the result that would be obtained by halving the A 60-year-old man develops a tremor in his An 8-year-old boy needs to be coaxed to go to fingers. The tremor is most pronounced when he school and, while there, often complains of reaches for his coffee cup or points to an object. severe headaches or stomach pain. His mother Which of the following components of the motor frequently has to take him home because of his symptoms. At night, he tries to sleep with his parents. When they insist that he sleep in his own room, he says that there are monsters in his closet. Which of the following best explains this (D) Frontal eye field (E) Motor nucleus of the thalamus (A) Childhood schizophrenia (B) Normal concerns of latency-age A patient being treated with clindamycin for aspiration pneumonia develops diarrhea. The stool contains a toxin that kills cultured epithelial cells. Stool culture grows an anaerobic gram- positive rod. The same organism is cultured from his bedpan. Which of the following is most likely to sterilize the bedpan? An 18-year-old female athlete reports easy fatigability and weakness. Physical examination shows no abnormalities. Laboratory studies (B) Exposure to benzalkonium chloride for (C) Exposure to ethyl alcohol for 1 hour (D) Exposure to saturated steam (121°C) for An 18-year-old woman has gastroenteritis with nausea and vomiting and is able to ingest only small amounts of water. After 3 days, she develops light-headedness, especially when sitting or standing. Arterial blood gas analysis is Which of the following is the most likely most likely to show which of the following sets (B) Anxiety reaction with hyperventilation A 45-year-old man has abnormal circadian variation in body temperature, disruption of the A 10-year-old boy is severely burned. Nitrogen sleep-wake cycle, and an impaired nocturnal loss occurs during the first few days after the surge of secretion of melatonin. An MRI of the burn. During this acute period, which of the brain is most likely to show a lesion involving following substances plays a major role in In patients with AIDS, the failure to form granulomas in tissues infected by Mycobacterium tuberculosis is most likely due to which of the following? (B) Decreased production of tumor necrosis (C) Inability of T lymphocytes to provide (D) Inability of T lymphocytes to recruit Cells from a single population are suspended in solutions X and Y, and cell volume measurements are made. The graph shows the volume of cells in solution X (solid curve) and Hospital discharge of a 75-year-old man is solution Y (dashed curve). The results indicate delayed due to unavailability of a bed in a that solution Y, with respect to X, is which of the nursing home. He is bedridden and unable to attend to his personal needs. During a 3-day period, his pulse increases from 82/min to 125/min, and blood pressure decreases from 124/72 mm Hg to 100/55 mm Hg. Laboratory The nervous system increases the force of muscle contraction in a graded fashion primarily by recruitment of active motor units and by (A) Amplitude of action potentials of single (B) Duration of action potentials in single Which of the following is the most likely (E) Rate of synthesis of acetylcholine at the (D) Gastrointestinal hemorrhage (E) Syndrome of inappropriate ADH A 60-year-old woman who has had four children and completed menopause 6 years ago develops Gram-positive cocci in clusters are seen in urinary incontinence whenever she coughs, purulent fluid drained from a skin abscess. Rapid sneezes, or laughs. The physician should suggest identification of these organisms will be exercises to strengthen which of the following facilitated by evaluation of the clumping of latex beads coated with which of the following? (B) Interleukin-1 (IL-1) and factor VIII After infection with measles virus, a 6-year-old boy produces antibodies to all eight viral proteins. The next year he is again exposed to measles virus. Antibodies to which of the following viral proteins are most likely to be protective? (A) Hemagglutinin (B) Matrix (C) Nonstructural (D) Nucleocapsid (E) Polymerase A 45-year-old man has a left ventricular ejection fraction of 25% (N>55%) with diffuse hypokinesis. He has a sedentary life-style. He eats red meat up to 6 times weekly and drinks 4 alcoholic beverages daily. He is 185 cm (6 ft 1 in) tall and weighs 86 kg (190 lb); BMI is 25 kg/m2. His blood pressure is 90/60 mm Hg. Coronary arteriography shows no evidence of A 73-year-old woman has episodes of abdominal atherosclerosis. To prevent further heart damage, pain and increasingly severe constipation. Test of which of the following is the most appropriate the stool for occult blood is positive. The photomicrograph shows features of the resected colon. Which of the following is the most likely (B) Avoidance of alcohol (C) Ingestion of more vegetables and Oral administration of grapefruit juice increases A 1-day-old newborn is evaluated for possible the bioavailability of a variety of drugs, sepsis. Blood cultures grow gram-positive cocci including felodipine, midazolam, saquinavir, and in pairs and chains that agglutinate with group B verapamil. After oral administration of any one antiserum. The most likely epidemiologic risk of these drugs, which of the following is most factor for this infection involves bacterial likely to be increased in the presence of A 3-year-old boy with mental retardation has A 74-year-old man with urinary frequency and hepatosplenomegaly. Analysis of tissue obtained urgency has benign prostatic hyperplasia. He on biopsy of the liver shows unusually large refuses operative intervention but agrees to a trial amounts of glucocerebroside. Which of the of finasteride therapy. During the trial, synthesis following enzymes is most likely to be deficient? of which of the following substances is most (A) Hormone-sensitive lipase (B) Lipoprotein lipase A 23-year-old woman has a progressive increase Warfarin is administered to a 56-year-old man in her serum ȕ-human chorionic gonadotropin following placement of a prosthetic cardiac (ȕ-hCG) concentrations during an 8-week valve. The warfarin dosage is adjusted to period. A hydatidiform mole is removed, but the ȕ-hCG concentration continues to increase. trimethoprim-sulfamethoxazole therapy is begun Which of the following is the most likely for a recurring urinary tract infection. In addition to monitoring prothrombin time, which of the following actions should the physician take to (B) Choriocarcinoma (C) Ectopic pregnancy (C) Make no alterations in the dosage of A 30-year-old woman with a 1-week history of severe diarrhea feels dizzy when she stands up. Blood pressure (while supine) is 112/76 mm Hg with a pulse of 88/min; blood pressure (while standing) is 80/60 mm Hg with a pulse of An inherited metabolic disorder of carbohydrate 120/min. In addition to controlling her diarrhea, metabolism is characterized by an abnormally increased concentration of hepatic glycogen with intravenous administration of which of the normal structure and no detectable increase in observations suggest that the disease is a result of the absence of which of the following (B) Glucokinase (C) Glucose-6-phosphatase (D) Phosphoglucomutase A 60-year-old man has a 5-day history of productive cough and shortness of breath with exertion. In addition to a normal left lung base, examination of the chest in the area of the right A genetic male newborn has fully developed male sexual ducts and recognizable fallopian tubes. Which of the following processes was most likely disturbed during the embryonic Which of the following is the most likely (G) Pleuritis (H) Pneumothorax (I) Pulmonary Investigators are studying the use of a new grandmother have died of carcinoma of the laboratory test to identify patients with a breast refuses to have mammography. She says particular disease. The table below summarizes that she knows she is at risk but states, "I hate the results of initial research involving 200 having my breasts squashed–it's uncomfortable." Her physician would like her to have annual mammograms. Which of the following is most Test Result Negative 20 80 100
(A) Exaggerate her risk for breast cancer Which of the following is the approximate (C) Offer analgesia prior to mammography (D) Show her photographs of the results of (E) Tell her that the therapeutic relationship A 50-year-old man with a history of alcoholism A cardiac catheterization is done in a healthy has difficulty with short-term memory. He is person. The blood sample withdrawn from the unable to recall the date and cannot remember catheter shows 60% oxygen saturation, and the what he ate for breakfast this morning. He thinks pressure recording shows oscillations from a the examiner is a long-lost friend and carries on a maximum of 26 mm Hg to a minimum of 14 mm conversation with the examiner as if they have Hg. The catheter tip was located in which of the known each other for years. His long-term memory appears intact. The patient dies shortly thereafter of a myocardial infarct. Pathologic examination of his brain is most likely to disclose an abnormality involving which of the An inexpensive screening test for a disease is available through analysis of venous blood. The distributions of blood concentrations for persons with and without the disease are depicted in the graph. The disease is irreversible and fatal if not Two chemicals are isolated from the body. When discovered and treated early. Which of the administered at the same time, these chemicals following letters represents the most appropriate induce gastric acid secretion that is four times as cutoff point between normal and abnormal? great as that induced by either one alone. The two chemicals are most likely to be which of the following? (A) Acetylcholine and secretin (B) Gastrin and cholecystokinin (C) Gastrin and Several contiguous cells are labeled with a physician's office because of poor weight gain despite large food intake. He has had two membranes. One cell is experimentally bleached episodes of pneumonia and has frequent bulky with light that destroys the dye, but the cell soon stools. He coughs frequently. X-rays of the lungs recovers dye fluorescence. This recovery is best show increased markings and hyperinflation. explained by the presence of which of the Trypsin is absent in a fresh stool sample, and the following structures between the bleached cell fat content is increased. Which of the following is the most likely cause of this infant's disorder? (B) Defective ion transport at epithelial (E) Tight junctions (zonulae occludentes) (D) Inability to synthesize apolipoprotein B (E) Villous atrophy of the jejunum A 31-year-old man with a history of epilepsy has a major motor (grand mal) seizure. Laboratory Genes of laterality, such as iv or inv, determine values obtained immediately after cessation of the right-left axis ("sidedness"). A mutation in a laterality gene is the most logical explanation for a child who was born with which of the Hepatitis A virus (HAV) is resistant to solvents such as chloroform and 20% diethyl ether, while Which of the following is the most likely acid- HIV-1 is sensitive to such solvents. This resistance is best explained by absence of which of the following in HAV? (A) High anion gap metabolic acidosis (B) High anion gap respiratory acidosis (E) Normal anion gap respiratory acidosis A 6-year-old boy has a large intra-abdominal mass in the midline just above the symphysis pubis. During an operation, a cystic mass is A 66-year-old man has become increasingly found attached to the umbilicus and to the apex short-tempered with his wife. He has diarrhea, of the bladder. Which of the following is the weight loss, and weakness in the proximal muscles. He has atrial fibrillation and tachycardia. Which of the following is the most (C) Hyperthyroidism (D) Mitral valve prolapse (E) Pheochromocytoma A 25-year-old man is started on clozapine for A 76-year-old man with a history of prostatic schizophrenia, paranoid type. He had been hypertrophy has the recent onset of increased unsuccessfully treated for the past 2 months with difficulty urinating. Symptoms began shortly haloperidol. The patient should be monitored for after he started taking a nasal decongestant orally for cold symptoms. Which of the following types of receptors is most likely to be involved in these (B) Decreased leukocyte count (C) Decreased platelet count (D) Nicotinic receptor at the neuromuscular A 49-year-old man is taken to the emergency department because of neck pain that began after the car he was driving was hit in the rear by a pick-up truck. X-rays of the neck show no cervical fractures. A diagnosis of "whiplash" is made, and he is fitted with a neck brace. Several hours later he begins to have headaches and numbness in the scalp over the left occipital region. The most likely cause is compression of which of the following structures on the left? (A) Cervical spinal cord (B) Ophthalmic division of the trigeminal (C) Second cervical nerve root (D) Spinal accessory nerve (E) Vertebral The graph shows urine/plasma osmolarity versus urinary flow rate in a healthy human subject. Which of the following most likely produced the change from X to Y? (A) Oral ingestion of 1 L of water (B) Oral ingestion of 200 mL of a 0.9% (D) Oral ingestion of 200 mL of a 3% saline

Source: http://histol.med.stu.edu.cn/USMLE/2008step1%E6%A8%A1%E6%8B%9F%E8%80%83%E8%AF%951.pdf