NBME 13

What strucuture attaches to the cervical region and extends posteriorly

A 54 y/o woman comes to the physician because of a 5-day history of severe mid-back pain Physical examination shows point tenderness over the T6 vertebra. Serum studies show a calcium concentration of 13.4 mg/dl; urinalysis shows Bence Jones proteins. Which of the following is the most likely cause of this patient's hyper-calcemia?

Chronic mal-absoprtion + retinal degeneration + ataxia + motor dysfunction + low cholesterol

Exposure to paint thinner + Dilated pupils + vomiting, confusion, difficultly walking

Which of the following structures can be cut to decrease stomach acid output and decrease likelihood of ulcers forming in jejunum

Sequence analysis of mitochondrial DNA shows a mutation in 50% of the mothers mitochondria DNA and in 100% of each other children's mitochondrial DNA. A pedigree is shown. Which of the following genetic principles best explains the findings in this family?

A 52 year old man with a family history of renal failure comest to the physician because of abdominal pain over the last 6 months. He has been treated in the past for renal calculi and hypertension. Physical examination shows bilateral palpable masses in the upper abdomen. Urinalysis shows crenated erythrocytes and mild proteinuria. A CT scan of the abdomen identifies the cause of the patient's problem. Which of the following is the most likely diagnosis?

Previously healthy 6 y/o girl presents with abdominal pain + nausea + vomiting 4 hours after attending a friends birthday party; What is the cause of these findings?

A 39-year-old woman with end-stage renal disease caused by systemic lupus erythernatosus undergoes kidney transplantation from a living, unrelated donor. Despite aggressive immunosuppressive therapy, the transplant is rejected after 6 months. Analysis of a biopsy specimen of the transplant shows numerous infiltrating CD8+ T lymphocytes. Which of the following is the most likely cause of rejection of the transplant in this patient?

A male newborn is delivered at 38 weeks' gestation following an uncomplicated pregnancy. Twelve-hours later, he begins sucking frantically and crying inconsolably. He overreacts to stimuli around him and has a marked startle response. The symptoms slowly resolve over the next 2 to 3 weeks. The most likely explanation for these symptoms is maternal use of which of the following substances during pregnancy?

A 22-year-old woman comes to the physician for a follow-up examination. One year ago, she was diagnosed with a pulmonary embolism. Two years ago, she delivered a female stillborn at 23 weeks' gestation. Physical examination today shows no abnormalities. Laboratory studies show a platelet count of 250,000/mm3, a prothrombin time within the reference range, and an increased partial thromboplastin time. The findings in this patient are most consistent with which of the following conditions?

A 36-year-old man comes to the physician for a routine examination. He has a 5-year history of recurrent episodes of genital herpes treated with acyclovir. He says, "I`ve been taking the medication, but I still occasionally get lesions. When will I be cured?" The physician informs him that herpes simplex is a lifelong infection, with no cure at the present time. Which of the following best explains the longevity of the herpes simplex virus?

A mouse melanoma, B-16. is highly metastatic. A clone of the B-16 melanoma cells is injected intravenously into the tail vein of mice, and 3 weeks later tumor nodules are found in the lungs, liver, and ovaries. When an antibody to a liver cell surface antigen is injected 1 hour prior to injection of the B-16 melanoma cells, formation of tumor nodules in the liver is prevented, but tumor nodules develop in the ovaries and lungs. In vitro studies do not show any cytotoxic effect of the antibody on B-16 or hepatic cells. Which of the following processes is most likely to be affected by the antibody?

A study is conducted to assess the effectiveness of vitamin C in preventing common colds in children, Patients are randomly assigned to receive either vitamin C or no intervention. Outcome events (common cold) are reported by the parents on a monthly basis for 1 year. Results show that those taking vitamin C have fewer colds compared with those who received no intervention (p<0.05). Which of the following raises the most concern about the validity of the conclusion that vitamin C supplements prevent the common cold?

A 23-year-old woman is treated with acetazolamide to prevent acute altitude sickness 3 days before going on a mountain-climbing expedition. Acetazolamide acts predominately in which of the following areas of the kidney in this patient?

A 40-year-old woman is brought to the emergency department 30 minutes after sustaining severe chest injuries in a motor vehicle collision. Despite appropriate treatment, she dies 1 hour later. She had a 25-year history of a well-controlled seizure disorder. A photograph of a coronal section of the brain obtained at autopsy is shown. Which of the following is the most likely cause of this patient's seizure disorder?

A 72-year-old woman is admitted to the intensive care unit after undergoing immediate operative repair of a ruptured colonic diverticulum. During the next 2 weeks, she develops recurrent fevers. After a blood culture grows yeast, micafungin therapy is initiated. This drug most likely targets which of the following cellular structures?

A 60 year-old man comes to the physician because of weakness and light-headedness for 3 months. His diet consists of a healthy balance of fruits, vegetables, whole grains, and lean chicken and fish. He has a 10-year history of chronic autoimmune (Hashimoto) thyroiditis treated with thyroxine. Physical examination shows pallor. Serum studies show increased concentrations of methylmalonic acid and total homocysteine. A peripheral blood smear shows megaloblastic anemia. Which of the following is the most likely cause of the findings in this patient?

An 18-year-old man comes to the physician 6 hours after he twisted his ankle while playing football. Physical examination shows looseness of the lateral collateral ligament, suggestive of a tear. Lack of which of the following components in the ligament will most likely limit healing of this injury?

A 62-year-old man is brought to the emergency department because of a 3-hour history of progressive difficulty breathing and mild left shoulder pain. His symptoms began after he ran up several flights of stairs. He has poorly controlled hypertension and mild angina pectoris. He has smoked one-half pack of cigarettes daily for 40 years. He appears uncomfortable and has labored breathing. Diffuse crackles, rhonchi, and scattered wheezing are heard on auscultation of the posterior lung fields. His arterial Po2 is 58 mm Hg. Which of the following is the most likely diagnosis?

A previously healthy 25-year-old man is admitted to the hospital for treatment of viral pneumonia. He is mechanically ventilated because of respiratory failure due to hypoxemia. An open-lung biopsy specimen is obtained and shows a pattern of acute lung injury. The presence of which of the following in the biopsy specimen most clearly suggests diffuse alveolar damage rather than bronchiolitis obliterans-organizing pneumonia in this patient?

A 38-year-old woman at 32 weeks' gestation is brought to the physician because of a 2-day history of fever, nausea, vomiting, and muscle aches. She appears acutely ill. Her temperature is 39C (102.2F). pulse is 120/min, and respirations are 20/min. A photomicrograph of a Gram stain of an organism recovered from a blood culture is shown. Which of the following is the most likely causal organism?

A 76-year-old woman is brought to the emergency department because of a 3-hour history of severe headache, slurred speech, and confusion. She has a 2-year history of atrial fibrillation. She has difficulty understanding and answering questions, but she is cooperative. Ophthalmologic examination shows hemianopia and a tendency to gaze to the right. The pupils are normal sized and reactive to light. Neurologic examination shows left-sided numbness and paralysis that are more severe in the face and upper extremity than in the lower extremity. Which of the following arteries is most likely involved in this patient's condition?

An 82-year-old woman is admitted to the hospital for treatment of a small right pleural effusion. Physical examination shows dullness to percussion at the level of the 7th rib and below on the right. A thoracentesis is done. The patient is sitting up, supported by leaning against a bedside table. After preparing the skin and delivering a local anesthetic, into which of the following locations on the right is it most appropriate to insert the catheter?

A 55-year-old man with hepatic encephalopathy is brought to the physician because of confusion and increased lethargy during the past 24 hours. He has a history of cirrhosis of the liver caused by hepatitis C. He is easily arousable despite the lethargy. His temperature is 37C (98.6F), Physical examination shows scleral icterus, asterixis, a protuberant abdomen, and ascites. Test of the stool for occult blood is negative. Administration of which of the following drugs is most likely to improve this patients mental status?

Patient has Diabetes insipidus. Describe the tubular osmolality in the kidney

A 10 - year old boy who has had type 1 diabetes mellitus for 1 year is receiving insulin. One hour after his morning dose of insulin, he becomes tremulous and diaphoretic and has tachychardia. Several hours later, his symptoms resolve. His blood glucose concentration is now increased. Which of the following is the most likely cause of this patient's hyperglycemia?

A 63-year old man comes to the emergency department 30 minutes after the sudden onset of right-sided chest pain and shortness of breath that began after a 10-hour drive in his truck. The pain is more sever with inspiration. He does not smoke cigarettes. His pulse is 110/min, and respirations are 32/min. the lungs are clear to auscultation. Which of the following findings is most likely on ventilation-perfusion lung scans?

A 70-year old man comes to the emergency department 30 minutes after the onset of weakness, nausea, and lower abdominal and back pain that radiates to the lower extremities. He appears pale and has a cold sweat. Pulse is 110/min and blood pressure is 90/60 mm Hg. Pulses in the lower extremities are weak. A faint bruit is heard in the lower abdomen. Muscle stretch reflexes are normal in both lower extremities. Which of the following is the most likely diagnosis?

During autopsy, histologic examination of a liver section shows disruption of the normal hepatic lobule. Small shrunken hepatocytes with intense eosinophilic cytoplasm, fragmented nuclear chromatin, and cytoplasmic bleb formations are noted. Which of the following processes is most likely occurring in the hepatocytes described?

A 72-year old woman comes to the emergency department because if bloody diarrhea for the past 12 hours and diffuse abdominal pain for the past 4 days. History includes a cerebral infarction 3 years ago from which she completely recovered. Examination shows watery stool with red blood. Colonoscopy shows patchy ulceration at the area near the splenic flexure. Which of the following is the most likely diagnosis?

A 31-year old woman is brought to the emergency department by her husband because of difficulty breathing and severe muscle weakness for 10 minutes. She has a 3-year history of myasthenia gravis treated with neostigmine. The husband reports that she doubled her dosage 2 days ago because she was feeling extraordinarily weak, but her weakness has increased since then. Which of the following events is the most likely cause of the increased muscle weakness in this patient?

During an experiment, Drug X is administered to treat trematode and cestode infestations. Results show that Drug X increases the permeability of the cell membranes to calcium, causing paralysis, dislodgement, and death of the parasite. Drug X most closely resembles which of the following?

A 23-year old woman is brought to the emergency department 45 minutes after sustaining an injury to her right shoulder when she was forcefully thrown into a swimming pool. The patient is holding her right arm in external rotation. There is an area of tenderness and absent sensation over the lateral aspect of the forearm. Immediately after reduction of the glenohumeral joint, she is unable to flex the elbow against gravity. Which of the following structures is most likely injured in this patient?

A prospective study examined the relationship between the development of gastric cancer and exposure to a diet rich in selenium. The investigators estimated the relative risk of gastric cancer to be 0.3 in individuals with a high-selenium diet (95% confidence interval 0.1-0.8). Which of the following is the most appropriate interpretation of this finding?

A 23-year old woman with type 1 diabetes mellitus is brought to the physician for a follow-up examination. She has a 2-year history of recurrent yeast infections. Genetic analysis shows a deficiency of myeloperoxidase. Which of the following is the most likely cause of the increased susceptibility to infections in this patient?

A 25-year old woman undergoes a radical mastectomy with removal of the axillary lymph nodes on the left side. After the operation, she develops painful edema of the left upper extremity. Which of the following therapies is most likely to decrease the swelling in this patient?

A 33-year-old woman who is right-handed is brought to the physician because of a 3-day history of progressive weakness and numbness of her arms and legs. Neurologic examination shows proximal and distal weakness of the upper and lower extremities. There is areflexia. Sensation to vibration and joint position is decreased in the fingers and toes. Nerve conduction studies show a slow conduction velocity in the median, ulnar, peroneal, and tibial nerves. These electrophysiologic findings most likely indicate impaired function of which of the following ion channels?

A study is conducted to evaluate the onset and course of cardiovascular disease in African American men and women in the USA. Census data from the year 2000 are used to select the study sample. A series of factors including family income and years of education is defined. Census data most representative of the national census data for the factors selected are used for sampling.Which of the following best describes this sampling technique?

A 15-year-old boy is brought to the physician by his father because of behavioral changes during the past month. He has been failing his classes at school and staying out late at night. His father reports that the family moved to a new neighborhood 2 months ago, and that the local teenagers are mall drug addicts and criminals." His pulse is 110/min, respirations are 24/min. and blood pressure is 140/85 mm Hg. Physical examination shows pupillary dilation and diaphoresis. On mental status examination, his affect is agitated, and his thought process is confused. Intoxication with which of the following substances is the most likely cause of this patient's symptoms?

An autopsy is done on a 46-year-aid woman who died of adenocarcinoma of the colon. Examination of the neck shows a 5-cm, rounded mass next to the bifurcation of the carotid artery. A section of the mass is shown in the photomicrograph. Immunohistochemistry of the section is positive for synaptophysin, chromogranin and neuron-specific enolase_ Electron microscopy shows numerous electron-dense, membrane-bound neurosecretory granules. Examination of the adrenal glands shows no masses. Which of the following is the most likely diagnosis?

What is the most likely reason for the persistent colonization of P. aeruginosa in bronchopneumonia

Twenty subjects participate in a study of cardiopulmonary physiology. The pulmonary circulation of these subjects most likely has which of the following characteristics compared with their bronchial circulation?

A 40-year old man comes to the physician because of a 6-month history of difficulty maintaining an erection during sexual intercourse. He has consumed ½ L of bourbon daily for 15 years. His pulse is 88/min and his blood pressure is 130/80 mm Hg. Examination shows scleral icterus and spider anglomata over the trunk. The liver span is 5 to 6 cm in the midclavicular line. The spleen tip is palpated 5 to 6 cm below the left costal margin. Decreased serum concentrations of which of the following is the most likely cause of this patient's erectile dysfunction?

. A 32-year old woman comes to the physician because she has not been able to conceive for 5 years. Previous fertility examinations of her husband showed no abnormalities. Menses occur at regular 28-day intervals. Her blood pressure is 110/70 mm Hg. Physical and pelvic examinations show no abnormalities. Hysterosalpingography shows normal findings. Her serum hormone concentrations are within the reference range. Which of the following is the most appropriate pharmacotherapy for this patient's infertility?

A previously healthy 40-year old man is brought to the emergency department 1 hour after the onset of severe pain in his left leg while playing tennis. He is found to have ruptured the left Achilles tendon and undergoes operative repair and long leg cast immobilization. Six months later, the left calf shows a 2-cm decrease in circumference compared with the right calf. Which of the following is the most likely cause of this decrease?

A 47-year-old woman comes to the physician because she wants to "do something about my wrinkles." Physical examination shows fine wrinkles in photodamaged skin on the face. Treatment with tretinoin is started. Collagen synthesis will most likely be increased in this patient by which of the following mechanisms?

A 54-year-old man has a squamous cell carcinoma of the right lung. Analysis of his germline DNA shows two alleles, m and n, at the microsatellite locus Z tightly linked to the p53 gene. Similar analysis of the neoplastic cells shows the presence of the m allele only. These findings are most likely due to which of the following processes?

A 49-year-old man is brought to the emergency department 30 minutes after fainting in the street. He regained consciousness 1 minute after fainting. He says that he has had watery diarrhea during the past 5 days, which has not improved with fasting. He has not changed his diet or travelled overseas recently. His blood pressure is 90160 mm Hg. Physical examination shows a flushed face and dehydration. Serum studies show a potassium concentration of 2 mEg/L and glucose concentration of 150 mg/dL. He is admitted to the hospital, and intravenous fluid replacement is started. Over the next day, he passes a stool with a volume of 3.5 L. Which of the following is the most likely cause of this patients diarrhea?

A 60-year-old woman comes to the physician because of a 2-day history of flank pain and pain with urination. She has hypertension, recurrent urinary tract infections, and hypothyroidism. Her temperature is 37°C (98.6`F), pulse is 961min, and blood pressure is 152192 mm Hg. Physical examination shows no other abnormalities. Urinalysis shows 3+ blood, 1+ leukocytes, and few bacteria. Ultrasonography of the abdomen shows a large calculus filling the entire right renal pelvis. The renal calculus in this patient is most likely composed of which of the following substances?

A 76-year-old man with congestive heart failure comes to the physician because of a 1-month history of shortness of breath after walking up a flight of stairs. He has had frequent nausea, and he has had to use two pillows to sleep during this period. Diffuse, moist crackles are heard over bath lungs. There is pitting edema above the ankles. Which of the following best describes the function of the product secreted by the atrial myocytes in this patient?

A 32-year-old man comes to the physician because of back pain and joint stiffness for 3 months. His symptoms improve after mild exercise. During this illness, he also has had fatigue and a 3.2-kg (7-1b) weight loss. Physical examination and x-rays of the sacroiliac joints confirm a diagnosis of ankylosing spondylitis. Which of the following laboratory tests would be most appropriate for the patient's two children to evaluate their susceptibility to this disease?

A 55-year-old man comes to the physician because of intermittent heartburn during the past 3 months. He says that he has approximately two episodes weekly during which he develops burning pain between his chest and abdomen when he lies down for a nap after dinner. A bitter taste sometimes accompanies the pain. He often has an alcoholic drink before dinner and several glasses of wine with the meal. He is 178 cm (5 ft 10 in) tail and weighs 113 kg (250 lb); BMI is 36 kg/m2. Physical examination shows no other abnormalities. In addition to weight loss and decreased alcohol consumption, which of the following drugs is most appropriate for this patient?

A 92-year-old man is brought to the emergency department because of a 6-hour history of chest pain and shortness of breath. A diagnosis of congestive heart failure is made. Diuretic therapy is initiated, and his symptoms resolve over the next 3 days. However, his pulse remains at 44(min, and he has fatigue with minimal exertion. His physician believes that he should receive a pacemaker, however, the patient has expressed a desire to forego all invasive procedures. The physician presents the benefits of the pacemaker fully, but he describes the risks and follow-up in a cursory manner. The patient consents to the procedure. This physician has violated which of the following ethical principles?

A female newborn is delivered al 34 weeks gestation in an advanced-care setting where special delivery systems are available. The diagnosis of persistent pulmonary hypertension is made. Considering that the newborn can be carefully monitored for methemoglobinemia, which of the following is the most appropriate therapy?

A 19-year-old woman comes to the physician because of increasingly severe pain in the right hip during the past month. She has a 4-year history of refractory inflammatory bowel disease with arthritis in the hands treated with corticosteroids for the past 2 years, An x-ray of the pelvis shows collapse of the superior half of the right femoral head with preservation of the articular cartilage. The left hip appears normal. Which of the following is the most likely cause of the hip abnormality?

A 25-year-old man receives a bupivacaine injection for median nerve block as treatment of camel tunnel syndrome. Which of the following is the mechanism of action of this drug on the membrane?

A 33-year-old woman comes to the physician 3 days after she found a mass in her right breast on self-examination. Examination of the right breast shows a 2.5-cm, hard mass in the upper outer quadrant of the right breast. A photograph of the resected mass is shown. Which of the following characteristics of the lesion best predicts this patient's prognosis?

A 32-year-old man has had generalized band-like headaches and dizziness almost every day for the past 6 months. Physical examination and CT scan of the head show no abnormalities. Which of the following additional findings in this patient is consistent with a diagnosis of hypochondriasis rather than undifferentiated somatoform disorder?

Orlistat

A 26-year-old woman comes to the physician's office because of a 13.5-kg (30-1b) weight gain, irregular menstrual periods, constipation, and fatigue for the past 6 months. She also complains of increased difficulties with concentration and memory for the past month. Physical examination shows a blood pressure oil45/84 mm Hg, dry skin, and decreased muscle stretch reflexes at the ankles. Serum cholesterol concentration is 310 mg/dL, arid serum potassium concentration is 4.0 mEq/L, Determination of which of the following serum concentrations is most likely to confirm the diagnosis?

A 38-year-old woman is brought to the emergency department after being found lying on the sidewalk. She is conscious but says she is too weak to stand. Physical examination shows a red, swollen, tender tongue; angular stomatitis; and spoon-shaped nails. Hemoglobin and mean corpuscular volume are decreased. Which of the following is the most likely diagnosis?

A 5-year-old boy is brought to the physician by his mother because of progressive clumsiness and fatigue during the past 6 months. He says that his legs are tired. He was delivered at term after an uncomplicated pregnancy. He has met all developmental milestones, although there was some delay compared with other children his age. He is alert. He has difficulty rising from the chair, he uses his arms to push himself into a standing position. He is unable to jump with both feet together. Physical examination shows hypertrophy of the calf muscles. This patient most likely has weak hip adduction as a result of dysfunction of the muscle inserting onto the femur from which of the following locations?

A 63-year-old woman comes to the physician because of a 2-month history of a drooping left eyelid, intermittent pain of her left eye, and an unusually large pupil. Her husband has told her that the eye appears to be "looking sideways." Ophthalmologic examination shows ptosis, lateral strabismus, and mydriasis of the left eye. An MRI of the brain shows an aneurysm of the left posterior communicating artery. The function of which of the following muscles is most likely to remain intact in this patient?

A 25-year-old medical student whose father had alcoholism and died of cirrhosis initially gets angry at patients with alcoholism. Over the course of training, he continues to recognize that working with these types of patients is distressing to him, but he learns methods of dealing more effectively with them. Which of the following mental mechanisms best describes his ability to effectively control his emotions?

A 22-year-old nulligravid woman develops right flank pain 3 days after undergoing an appendectomy and right ovarian resection because of an appendiceal abscess. Menses occur at regular 28-day intervals. Vital signs are within normal limits. Physical examination shows mild right flank tenderness. The most likely cause of this patient's pain is the accidental ligation of which of the following structures on the right?

A 23-year-old woman comes to the physician because of a 3-week history of persistent cough that is worsened by the cold air in her drafty apartment. She does not smoke, takes no medications, and has no history of asthma or chronic pulmonary disease. Physical examination shows no abnormalities. Short-term cough suppressant treatment is initiated with a drug that does not cause constipation and has a low potential for substance abuse. This drug is most likely which of the following?

A 95-year-old man who is a resident de skilled nursing care facility is brought to the emergency department because of a 1-day history of temperatures to 39.4°C (102.9°F), headache, cough, and muscle aches. Several other residents have similar symptoms. Physical examination shows no other abnormalities. Treatment with a neuraminidase inhibitor is begun. This drug most likely will inhibit which of the following processes, therefore decreasing the duration of this patent's symptoms?

A 30-year-old woman is brought to the emergency department 6 hours after the onset of severe abdominal pain and confusion. Her brother, father, and paternal grandmother had similar problems. Two weeks ago, she began a low-calorie diet. Her pulse is 120/rnin, and blood pressure is 1601110 mm Hg. Physical examination shows restlessness, excess sweating, and tremors. There is no abdominal tenderness. Urine studies show an increased porphobilinogen concentration. Which of the following is the most likely pattern of inheritance causing this patient's condition?

A throat culture grows group A Streptococcus. Because he is allergic to penicillin, treatment with erythromycin is begun. His condition improves during the next 2 days. The effectiveness of this antibiotic is most likely due to which of the following actions in protein synthesis?

A male newborn at 34 weeks' gestation is delivered vaginally. Physical examination shows no abnormalities except for a 1-cm, raised, red area on the anterior section of the neck. His mother is concerned, and the physician explains that the lesion is a hemangioma, a benign growth. This neoplasm most likely originated in which of the following tissues?

A 3-year-old girl is found to have a grade 4/6, loud, harsh, high-pitched holosystolic murmur that radiates over the precordium and a palpable thrill at the left sternal border. Which of the following defects is most likely in this patient?

Physical examination shows an enlarged right ovary. The result of a urine pregnancy test is negative. Ultrasonography of the pelvis confirms the presence of an enlarged ovary, and Doppler ultrasonography shows decreased adnexal flow. Which of the following structures is most likely affected in this patient?

Physical examination shows a typical male-pattern distribution of hair. Genital examination shows no abnormalities. Serum studies shows thyroid-stimulating hormone concentration of 2 µU/mL, prolactin concentration of 120 ng/mL, and total testosterone concentration of 25 mmol/L (N=10— 35). Semen analysis shows a markedly decreased sperm count with impaired motility. An MRI of the brain shows a 1-cm lesion in the pituitary gland. Administration of which of the following is the most appropriate treatment for this patient?

A 42-year-old man has an autoimmune disorder resulting in proximal muscle weakness of the lower extremities. Arrows in the photomicrograph shown indicate membranes that contain high concentrations of channels that are targeted by this condition. Which of the following is the most likely diagnosis?

A 45-year-old woman has a 2-week history of a heart murmur and hepatomegaly. She has a 3-month history of flushing with hypotension and crampy diarrhea. Which of the following is the most likely site of a primary neoplasm in this patient?

A 42-year-old man comes to the physician because of a 4-week history of muscle cramping and pain. Two months ago, he began treatment with simvastatin (80 mg daily) for hypercholesterolemia. After 1 month, marked improvement was noted in his serum LDL-cholesterol concentration, but serum triglyceride concentration remained increased. At that time, gemfibrozil was added to his regimen to decrease his triglyceride concentration. Physical examination today shows no abnormalities. This patient's myalgia is most likely related to which of the following effects of gemfibrozil on simvastatin?

A 3-year-old girl is brought to the emergency department by her mother 1 hour alter she was found with a half-empty bottle other grandmother's diabetes medication. The mother tells the physician that the child consumed approximately 25 metformin tablets. Physical examination shows no abnormalities. This patient is at greatest risk for which of the following serum abnormalities?

Physical examination shows weakness of the left lower extremity. Serum studies show an increased lactate concentration. Analysis of a calf muscle biopsy specimen obtained from the left lower extremity shows ragged red fibers. Which of the following metabolic processes is most likely impaired in this patient?

A 25-year-old woman comes to the physician because of a 2-day history of decreasing urine output despite ample fluid intake. She underwent operative removal of a perforated appendix 3 weeks ago. She received intravenous gentamicin for 2 weeks. Physical examination shows no abnormalities. Laboratory studies show: Histologic examination of this patient's kidneys would most likely show necrotic cells in which of the following components of the nephron?

A researcher in a pharmaceutical company designs a new protease inhibitor that inhibits replication of HIV in T lymphocytes in culture. In subsequent assays, which of the following findings is most likely to indicate that the compound is working specifically as a protease inhibitor?

A 65-year-old woman with diabetic ketoacidosis has had a fever and proptosis of the left eye over the past 3 days. She is unable to move the left eye. A black eschar is present on the nasal mucosa. Which of the following is the most likely diagnosis?

A 44-year-old woman has had pain, swelling. and stiffness in both hands over the past 6 months. The pain and stiffness are worst in the mornings, but symptoms improve with activity. Examination shows painless nodules on the extensor surfaces of the arms and tenderness and swelling of the metacarpophalangeal and proximal interphalangeal joints. Which of the following is involved in the pathologic process affecting her joints?

A 60-year-old woman with a 1-year history of diabetes mellitus has had decreasing vision over the past year. Examination of the eyes shows milky opacity of both lenses. Which of the following aberrant metabolites of glucose is most likely responsible for the formation of this abnormality?

A 12-year-old African American girl is brought to the emergency department by her mother because of a 6-hour history of fever and severe rib pain. She has had numerous episodes in the past. Her paternal aunt and uncle have had similar symptoms since youth. Her temperature is 39°C (102.2°F). The lungs are clear to auscultation. Abdominal examination shows tenderness to palpation. A peripheral blood smear is shown in the photomicrograph. Which of the following is the most likely underlying cause of this patient's symptoms?

Sequencing of the B-globin gene shows a point mutation in a sequence 3' to the coding region in which AATAAA is converted to AACAAA. Consequently, the amount of mRNA for B-globin is decreased to 10% of normal. Which of the following functions in mRNA synthesis and processing is most likely encoded by the sequence AATAAA?

55-year-old man recovered from a stroke 2 months ago He lives alone. He is at increased risk for which of the following psychiatric disorders?

An investigator breeds a transgenic strain of mice that develops severe fasting hypoglycemia. Administration of glucagon does not correct the hypoglycemia, but administration of epinephrine results in an increase in the serum glucose concentration. Which of the following proteins is most likely defective in this mouse strain?

54 y/o has light headness after skiing at an altitude of 2743 + He has been taking a carbonic anhydrase inhibitor since 2 days before arrival at the resort + He has orthostatic hypotension; Why does the patient have hypotension?