Miam

Assuming that a single laboratory test done on healthy volunteers has a 5% chance of falling outside the "normal" range, which of the following formulas expresses the probability of obtaining no abnormal results in eight statistically independent laboratory tests done on healthy subject?

(0.95)^8 OR 1-(0.05)^8

A 9-year-old boy is brought to the physician because he told his teacher that his fingers felt "funny" after he swung on the monkey bars 2 hours ago. Neurologic examination shows numbness and tingling in the ring and small fingers of the left hand. The physician concludes that the ulnar nerve may have been stretched while he was hanging from the bars. Which of the following other functions should be checked to assess the integrity of the ulnar nerve in the left limb?

Abduction of the index, middle, ring, and small fingers

An 18-year-old man has iof his feet and extensor tendons of his hands. Examination of tissue obtained on biopsy of one nodule shows a collection of foamy histiocytes within the dermis. His serum cholesterol concentration is 980 mg/dL, and serum lipoprotein electrophoresis shows a selective increase in LDL. Which of the following is most likely underlying disorder?

Absence of functional LDL receptors in hepatocytes

A 27-year-old man dies suddenly while playing handball. At autopsy, the heart weighs 750g and shows marked asymmetric septal hypertrophy with outflow obstruction the lesion is most likely to involve which of the following?

An autosomal dominant allele

50-year-old man with rheumatoid arthritis comes to the physician because of recent worsening of symptoms as well as increasing fatigue one month after starting therapy. Laboratory studies show: Hemoglobin 9.6g/dL Hematocrit 29% Mean Corpuscular volume 77 micro m Platelet count 200,000/mm Serum Iron 30 micro g/dL Total iron binding capacity 150 micro g/dL Which of the following is most likely diagnosis?

Anemia of chronic disease

Five tow-generation families with myotonic dystrophy are assessed. The table shows the ages of the onset of clinical symptoms in all affected individuals. Family Membe r Age of Onset(years) 1 Mother 44 Son 39 2 Father 51 Daughter 52 Daughter 27 3 Father 23 Son 3 Daughter 5 4 Mother 34 Son 27 Son 11 Daughter 1 5 Mother unaffected Father unaffected Daughter 42 Which of the following best explains these data findings about myotonic dystrophy?

Anticipation

A 68 year old man is brought to the emergency department because of a 3 day history of increasingly severe deep chest pain. He also has had shortness of breath, stridor, hoarseness, difficulty swallowing, and a nonproductive cough. He has a long-standing history of hypertension. He has smoked 2 packs of cigarettes daily for 45 years. His temperature is 37.2 degrees Celsius, pulse is 80/min, respirations are 15/min, and blood pressure is 160/94 mm Hg. The lungs are clear to auscultation. Physical examination shows a visible pulsation above the manbrium of the sternum and displacement of the trachea to the right. A murmur is heard in the second right intercostals space. Which of the following is the most likely diagnosis?

Aortic aneurysm

A patient with a 6- month history of heat intolerance, fatigue, episodes of tachycardia, and weight loss has a diffusely enlarged thyroid gland. Serum concentrations of triodothyronine (T3) and T4 are increased; thyroid stimulating hormone is decreased. Which of the following is the most likely diagnosis?

Autoimmune thyroid hyperplasia

A 86-year-old man with type I diabetes mellitus comes to the physician because of a two-year history of increasingly severe pain of his lower back, hips, knees, and legs. He has end stage renal disease that has been treated with dialysis for 20 years. Over the past year he has had two rib fractures and collapse of a lumbar vertebrae body that were not related to any apparent trauma. X-rays of the hands show subperiosteal erosions of the phalanges. A chronically increased serum concentration of which of the following is the most immediate cause of the skeletal findings?

Calcium

A patient with a 1-week history of diarrhea has reduced tissue turgor. Arterial pH is 7.3; serum bicarbonate concentration is 15 mEq/L. This patient is also likely to have which of the following?

Decreased arterial PCO2

A 26 year old woman comes to the physician because of a 3 day history of a low grade fever and sore throat. She has a history of illicit intravenous drug use. Her temperature is 38 degrees Celsius, pulse is 88/min, respirations are 28/min, and blood pressure is 138/88 mm Hg. Physical examination shows numerous white patches on the oropharynx numerous white patches on the oropharynx consistent with candidiasis. The patient is given a prescription for nystatin and counseled that further tests should be obtained to rule out an immunologic deficiency. Which of the following series of tests is most appropriate for this patient?

ELISA for HIV antibody, followed by western blot assay if positive

A 75-year-old woman is examined 3 weeks after undergoing operative repair of fracture of the right hip. Her physician plans to discharge her from the hospital and orders follow-up examinations with her primary care physician, physical therapy, and the use of a walker. In terms of payment for this outpatient health care, which of the following is the most appropriate next step when planning her discharge?

Ensure that the patient has part B of medicare insurance

A 60-year-old woman comes to the physician because of vaginal bleeding for 6 weeks. Menarche occurred at the age of 12 years, and menses had occurred at regular 30-day intervals. She had three term pregnancies by the age of 25 years. She has been receiving conjugated equine estrogen therapy since menopause 10 years ago. She has smoked 1 pack of cigarettes daily for 40 years. She drinks alcoholic beverages five times weekly. Physical examination and laboratory studies show no abnormalities. An endometrial biopsy specimen shows endometrial adenocarcinoma. Which of the following is the strongest predisposing rick factor for her biopsy findings?

Estrogen therapy

45-year-old homeless man is brought to the emergency department by police 30 min. after the onset of the generalized tonic clonic seizure. He has not eaten well for the past two weeks. On arrival, he has inebriated and is having tonic clonic movements of the extremities. His serum glucose concentration is 39 mg/dL. Intravenous administration of glucose stops the seizure, but the patient is responsible only to painful stimuli. Which of the following best explains this patient's decreased serum glucose concentration?

Ethanol induced increase of the NADH/NAD ratio

An otherwise healthy 25-year-old woman in the third trimester of an uncomplicated pregnancy has a hemoglobin concentration of 10.5 g/dL and a meacrit of 30%. The mean corpuscular volume and mean corpuscular hemoglobin are within the reference range. Which of the following is the most likely cause of her anemia?

Expansion of intravascular volume

An otherwise asymptomatic 52-year-old woman comes to the physician because of hot flashes. Her mensas have been irregular for the past 6 months. Which of the following is the most likely physiologic cause of her symptoms?

Failure of the ovaries to secrete 17 beta-estradiol

A previously healthy 20 year old woman has had a palpable lump in her right breast for the past 4 months. She has not had pain, swelling, or a nipple discharge. The lump is smooth, firm, round, mobile, nontender, and well delineated from underlying tissue. There are no changes in the skin around the lesion. Which of the following is the most likely diagnosis?

Fibroadenoma

A 42-year-old man comes to the physician because of chronic abdominal pain for three months. He describes his symptom as boring epigastric pain that is occasionally exacerbated by eating. He is an investment banker and describes his job as extremely stressful. Use of an over-the-counter histaminergic (H2)-receptors antagonist has mixed results. Vital signs are normal. Physical examination upper endoscopy showed no abnormalities. Which of the following is most likely diagnosis?

Generalized anxiety disorder

A 34-year-old woman with pyelonephritis has been treated with a bacterial antibiotic for four days with no improvement in her condition. And antibiotic that inhibits binding to the 30S ribosome, thereby blocking protein synthesis intracellularly, is added to her medication regimen. This antibiotic is most likely which of the following?

Gentamicin

An 82-year-old man is brought to the emergency department after his wife found him in bed this morning, unable to speak. The physician cannot elicit a history from him, either verbally or in writing. Neurologic examination shows weakness in his right lower face and right arm. When requested to do so, the patient contracts the muscles of his left arm with normal force. The patient most likely has which of the following types of aphasia?

Global

A 70-year-old man comes to the physician because of skin blistering for 1 week. He has had no oral lesions. Physical examination shows tense bullae in the joint folds of the upper and lower extremities. A biopsy specimen of the skin shows subepidermal blister formations. Direct immunofluoresence microscopy shows antibodies directed against proteins at the dermal-epidermal junction. Which of the following structures is most likely being targeted by the antibodies in this patient?

Hemidesmosomes

A 48-year-old man has the onset of shortness of breath and a nonproductive cough 2 days after undergoing a right knee operation. His temperature is 37.6°C (99.7°F), pulse is 122/min, respirations are 25/min, and blood pressure is 152/60 mm Hg. Pulse oximerty on 2 L/min of oxygen via nasal cannula shows an oxygen saturation of 85%. Physical examination shows swelling and tenderness of the left lower exteremity. Ventilation perfusion lung scans at the bedside show normal ventilation with a large perfusion defect in the right lower lung. The most appropriate next step in management is administration of which of the following?

Heparin

A developing fetus has failed to form kidney, which of the following processes is most likely to be affected in utero?

Production of amniotic fluid

A 56-year-old man with a history of alcohol dependence comes to the emergency department because of fever, night sweats, and a cough productive of bloody sputum. Laboratory studies of his sputum show numerous acid fast rods arranged in small arrays. Which of the following components of the casual organism may be directly cytotoxic to macrophages?

Teichoic acid

A male newborn is found to have a decreased blood thyroxine (T4) concentration on newborn screening. Physcial examination shows no abnormalities. Serum studies show decreased concentrations of triiodothyronine (T3) and T4. His serum free T4 and thyroid-stimulating hormone (TSH) concentrations are within the reference ranges. Which of the following best explains these findings?

Thyroid hormone binding globulin deficiency

A 36-year-old woman who is at 20 weeks' gestation comes to the physician for a scheduled examination. Her pregnancy has been uncomplicated, and her due date was established by ultrasonography at 10 weeks' gestation. Fundal height is greater than expected for gestational age. Ultrasonography shows markedly increased amniotic fluid volume. Which of the following abnormalities is the most likely cause of these findings?

Tracheoesophageal atresia

A 63 year old woman comes to the physician because of a 2 week history of daily episodes of severe, lancinating, left-sided facial pain. The pain, which occurs suddenly and lasts 30 to 60 seconds, shoots from the left ear down along the jawline. The pain is sometimes precipitated by chewing or brushing teeth. Vital signs are normal. Physical examination shows no abnormalities except for moderate dental caries. Which of the following is the most likely diagnosis?

Trigeminal neuralgia

A 48 year old man comes to the physician for a routine examination. He has a 6 month history of angina. His mother died at the age of 56 years of coronary artery disease. Physical examination shows no abnormalities. Serum studied show a total cholesterol concentration of 450mg/dL; LDL-cholestrol concentration is increased, and HDL-cholestrol and triglyceride concentrations are within the reference range. Following angiography and angioplasty of his circumflex coronary artery, treatment with a statin is begun. Statins are most likely to decrease this patients serum cholesterol concentration by which of the following mechanisms?

Upregulation of the LDL receptors

A patient with cancer who is undergoing radiation treatment develops the sudden onset of pain and tenderness on the left chest wall laterally, as well as mild fever and malaise. A vesicular eruption occurs that lasts for 3 weeks at the site of the pain. The most likely cause of this syndrome is reactivation of a latent infection caused by which of the following?

Varicella-zoster virus

This graph best depicts the natural history of which of the following human disorders?(image 279)

Yellow fever

A 30-year-old man comes to the physician because of a 2 day history of blood in his urine, dull flank plain, and voiding large amounts of urine. The patient states this his father died of an unknown kidney disease His blood pressure is 150/100 mm Hg. Physical examination shows bilateral renal masses. Laboratory studies show proteinuria and gross hematuria. A CT scan of the abdomen shows cystic masses in each of the kidneys; the right mass is larger than the left. A right nephrectomy is done; the surgical specimen is shown. The underlying defect most likely involves which of the following molecules? PICTURE

Polycystin

A 68-year-old woman is brought to the emergency department after her son finds her stuporous in her home. She reports that she was well when he last saw her two days ago. The patient is difficult to arouse. Temperature is 38.8*C (101.8*F), pulse is 110/min, and blood pressure is 80/50 mm Hg. The skin is flushed, warm, and dry. The remainder of the physical examination is normal. Laboratory studies show: Leukocyte count 27,500/mm Neutrophils 74% Lymphocytes 6% Band forms 18% Metamyelocytes 2% Urinalysis shows many leukocytes and gram-negative rods. Which of the following is the most likely explanation for the hypotension?

Multiple peripheral emboli

A 1-year-old girl has recurrent and chronic suppurative infections caused by staphylococci and some gram-negative rods. She recovers normally from viral infections. Examination of serum shows normal concentrations of complement components and immunoglobulins. Studies of leukocyte function are most likely to show defects in which of the following mechanisms?

Production of superoxide anions by neutrophils

A 27 year old man comes to the physician for a psychiatric evaluation at the request of his new employer because his coworkers think he is "very odd." He is employed as a computer repair specialist and lives alone. He refuses to socialize with anyone from work, and he has no friends that he sees regularly. He is extremely preoccupied with science fiction, the occult, and the afterlife, although he holds no particular religious beliefs. Which of the following personality disorders is the most likely explanation for his behavior?

Schizotypal

A 26-year-old man comes to the physician with his 27-year-old wife because of 2-year history of inability to conceive. Previous evaluation says his wife showed no abnormalities. Physical examination shows long upper and lower extremities and small tests. Laboratory status show an increased serum follicle- stimulating hormone concentration and estradiol: testosterone ratio. Cytogenetic studies show a 47,XXY karyotype molecular genetic studies show that one of the X chromosomes was inherited from the patient's father. An error of chromosome segregation most likely occurred during anaphase at which of the following stages of spermatogenesis in this patient' father?

Secondary spermatocyte

A 28-year-old nulligravid woman who has been unable to conceiver for 2 years undergoes an endometrial biopsy. Her menses occur at regular 28-intervals. Photomicrographs of the endometrial tissue are show. This patient is in which of the following phases of her menstrual cycle PICTURE

Secretory

A 27 year old primigravid woman at 39 weeks gestation is admitted to the hospital in labor. She has a 5 year history of type 2 diabetes mellitus currently treated with insulin. During the pregnancy, she has had difficulty controlling her serum glucose concentration. At a previous examination 1 week ago, her hemoglobin A1c was 8.4%. There is no family history of serious illness. On admission, the cervix is 100% effaced and 7 cm dilated; the vertex is at +1 station. Fetal weight is estimated at 4100 g (9 lb 1 oz). Which of the following is the most likely obstetric complication?

Shoulder dystocia

The frequency of Tay-Sachs carriers among Ashkenazi Jews is 1 in 30. The frequency of Tay-Sachs carriers among Caucasians of western European descent is approximately 1 in 300. Using this information, which of the following are the odds of having a child with Tay-Sachs if the mother is a Ashkenazi Jew and the father is a Caucasian of western European decent?

1 in 36000

In a survey of 100 households (average three residents per household), 45 individuals with asthma are detected. Which of the following is the best estimate of the prevalence of asthma?

15%

V = Vmax + (X) /divided Km+ (X) The Formula shown describes the rate of metabolism of drug X where v is the rate of metabolism, Vmax is the minimal rate of metabolism, and Michaelis constant (Km) is the plasma concentration at one half the maximum rate of metabolism. If the concentration of drug X is 100 times greater than the Km of the metabolic enzyme for drug X, which of the following conclusions is most appropriate?

A zero order rate of metabolism governs the reaction

35 year old man is brought to the emergency department because of a 2 hour history of severe fatigue and dizziness. He has had profuse, watery diarrhea for 8 hours despite a lack of oral intake. He recently returned from a medical relief trip to a remote village to Honduras. His temperature was 38.7 degrees Celsius, pluse is 122/min, and blood pressure is 90/50 mm Hg. Physical examination shows dry skin and decreased capillary refill. Test of the stool for occult blood is negative; the stool is gray and turbid. A Gram stain of the stool shows predominant gram-negative, common shaped bacteria; there are no qcychrocytes or lcukocytes. Which of the following best describes the mechanism of the toxin that caused these findings?

Activation by adenylyl cyclase

An 8-month-old is brought to the physician because of an onset of fearfulness over the past 2 weeks. Her mother describes her as a previously happy child who, at age 6 months, sat alone, ate and slept well, and was able to say "mama." She had been very sociable baby, but now she cries and clings to her mother when other adults try to pick her up. Which of the following best characterizes this patient in terms of cognitive, motor, and social development?

All normal

A 4-month old boy is brought to the emergency department because of a one-day history of respiratory distress. His parents say that he has had progressive weakness and difficulty feeding during the past month. His respiration is 50/min. physical examination shows a enlarged tongue and generalize hypotonia. Serum concentrations of lactate, pyruvate, glucose, and uric acid are within the reference ranges. A chest x-ray shows cardio medically. A biopsy specimen of skeletal muscle shows increase glycogen. Impairment of which of the following enzymes is the most likely cause of the abnormal glycogen storage in this patient?

Alpha 1, 4 phosphate

During an experiment, a researcher examines T lymphocytes found in the peripheral blood of a human subject. In the majority of these lymphocytes, the T-lymphocyte receptor is composed of which of the following chains?

Alpha and beta

An 85 year old man with mild narrow angle glaucoma and stable angina pectoris begins taking an over the counter drug containing diphenhydramine. Seven days later, his intraocular pressure is markedly increased. The most likely factor responsible for the increased intraocular pressure in this patient is blockade of which of the following receptors?

Alpha-adrenergic

A 20-year-old woman comes to the physician because of easy bruising for 2 weeks. She had been in good health except for a viral respiratory illness 1 month ago. Laboratory studies show thrombocytopenia. A bone marrow smear is shown. Which of the following is the most likely cause of her thrombocytopenia? PICTURE

Aplastic anemia

A 98 year old woman is brought to the physician for a routine examination. She has type 2 diabetes mellitus and hypertension. Current medications include atenolol, hydrochlorothiazide, metformin, and glipizide. She has had no chest pain or shortness of breath. She lives with her 75 year old daughter and 50 year old grandson and says that she is feeling fine. She walks 2 miles daily. She does not drink alcohol or smoke cigarettes. She has had a 6.3 kg (14 Ib) weight loss since her last visit 3 months ago. She is 157 cm (5ft 2in) tall and now weighs 37 kg (82 lb); BME is 15 15kg/m^2. Physical examination shows multiple ecchymoses in various stages of healing on the upper extremities and torso. While assessing this patient's condition, it is most appropriate for the physician to ask which of the following?

Are you safe at home?

A 56-year-old woman develops a restrictive cardiomyopathy, proteinuria, and renal failure. She has a 35 year history of rheumatoid arthritis. Renal biopsy shows a glomerular deposition of eosinophillic hyaline material; a Congo red staining shows a characteristic berifringent pattern when observed under polarized light. Which of the following features best explains the obtaining properties of this material?

Beta pleated sheet structure

16. A 72 year-old men comes to the physician because of a 2-week history of a nonproductive cough. He has non-Hodgkin lymphoma treated with a variety of antineoplastic drugs. Physicals examination shows hyperpigmentation around the elbows. A chest x-ray shows diffuse infiltrates. Which of the following drugs is the most likely cause of this patient's symptoms?

Bleomycin

A 73-year-old man comes to the physician with his wife because of a three-year history of daytime sleepiness. His wife says he snores loudly. He is 183 cm tall in ways113kg; BMI is 34kg/m. his pulse is 84/min, respirations are 18/min, and blood pressure is 175/105 mm Hg. Physical examination shows congested conjunctivae and centripetal of the city. Serum studies show a glucose concentration of 250 mg/dL, creatinine concentration of 2 mg/dL, and uric acid concentrations of 10.1 mg/dL. Polysomnography confirms the diagnosis, and the treatment with nasal continuous positive airway pressure at night is started. This therapy will most likely cause a decrease of which of the following?

Blood pressure

A 6-day-old female newborn is brought to the physician by her parents because of a 3 day history of difficulty feeding, vomiting, and progressive lethargy. Her parents have noticed that her urine has a burnt sugar odor. Physical examination shows lethargy and hypotonia. Deficiency of which of the flowing is the most likely cause of these findings in this patient

Branched chain alpha keto acid

A 26 year old nullivgravid woman is evaluated because she has been unable to conceive for the past year. She has had amenorrhea for 10 months and galactorrhea for 3 weeks. She has no history of stress or head trauma. She takes acetaminophen occasionally. Renal and thyroid function studies are normal. Which of the following is the most appropriate drug therapy?

Bromocriptine

A 54 year old man goes to his physician because of "arthritis" of the wrists and fingers. He has swelling of the wrists and clubbing of the fingers. X-rays of both arms show periosteal new bone formation involving the distal radius and ulna bilaterally and bulbous enlargement of the phalanges. Which of the following is the most likely underlying disorder?

Bronchogenic carcinoma

21-year-old woman comes to the physician because of a 10-day history of difficulty walking. Two years ago, she had loss of vision in the left eye which improved over 2 months. Neurologic examination shows decreased visual acuity in the left eye with pallor of the optic disc. She has past-pointing on a finger-nose test. She has a broad-based gait. An MRI of the brain shows lesions in the white matter of the cerebellum. Which of the following best describes the pathogenesis of the disease process in this patient?

CD4+ T lymphocytes are activated by myelin basic protein

A 61-year-old man has had three episodes of painless gross hematuria during the past week. The left flank is mildly tender to palpation. Urinalysis shows blood but no WBC's, bacteria or cellular casts. He says to the physician, "tell me like it is. Do I have cancer?" Which of the following is the most appropriate response?

Cancer is one of the possible causes of blood in your urine. We will need to perform additional tests to determine the cause

A 64 Year old man had progressive difficulty breathing over the past 3 weeks. X - Rays of the chest show fluid accumulation in the left pleural cavity. The fluid is milky white, and a fatty supernatant separates on standing. Which of the following is the most likely cause of the fluid accumulation

Cancer that is obstructing lymphatics

A 68-year-old man with alcoholism comes to the physician because of fever, chills, and a cough productive of purulent sputum for 3 days. Blood cultures are positive. Gram stains of sputum and blood show gram-positive, lancet-shaped diplococcic. Administration of a vaccine directed against which of the following bacterial compounds most likely would have reduced the disease severity in this patient?

Capsular polysaccharide

A 62- year-old man comes to the physician because of a lesion on his right hand for 2 yuears. Physcial examination shows a 2-cm, ulcerated, encrusted lesion on the dorsal surface of the right hand. A biopsy specimen of the lesion shows atypical keratinocytes, numerous mitoses, and apoptonic cells. Which of the following proteins most effectively identifies apoptonic cells in the skin of this patient?

Caspase

A 28-year-old man comes to the emergency department because of a 6-hour history of cramping and severe left midabdominal pain. He had a single episode of vomiting. His temperature is 37 °C (98.6°F). Abdominal examination shows a mass in the midabdomen. A CT scan of the abdomen with contrast is shown; the abdominally is indicated by the arrows. Intussusception of which of the following portions of the intestinal tract is the most likely cause of this patient's pain? Image on 336

Cecum

During a study on exercise, a 26-year-old woman runs on a treadmill for 30 minutes. Cardiac output increases three-fold. During exercise, the subject is most likely to have the smallest change in blood flow in which of the following organs?

Cerebrum

A 3-year-old boy is brought to the physician by his parents because of increasing irritability and hyperactivity during the past 3 weeks. His mother say, "He hasn't been eating as much, and he no longer plays peekaboo." The patient is uncooperative during the examination and constantly chews on the head of a plastic toy soldier. His gait is clumsy. Physical examination shows abdominal tenderness on palpation. Which of the following is the most appropriate treatment for this patient?

Chelating agent therapy

28 year old man comes to the physician for advice about infertility. He and his wife have been trying unsuccessfully to have children for the past 5 years. After a history and a physical examination, a drug is administered daily for 7 days to evaluate the patient's hypothalamic-pituitary axis. This treatment causes doubling of the serum luteinizing hormone concentration, a 50% increase in the serum follicle-stimulating hormone concentration, and increases in serum testosterone and estradiol concentrations. Which of the following drugs is most likely being used?

Clomiphene

A 40-year-old woman with a 2-year history of occasional headaches comes to the physician because of a 1-month history of intermittent excruciating, penetrating pain behind left eye accompanied by left-sided nasal congestion. The pain usually awakens her from a sound sleep and occurs once or twice nightly. She has no aura before these episodes. She has no history of major medical illness. Menses occur at regular 28-day intervals. Current medications include ibuprofen and a multivitamin. Physical examination shows no abnormalities. This patient most likely has which of the following types of headache?

Cluster

A researcher wants to evaluate the association between an environmental risk factor and a disease that has an incidence rate of 2/1000 per year. Which of the following is the appropriate study design?

Cohort study

A 49 year old man comes to the physician because of high lumbar back pain for 2 weeks. Physical examination shows no abnormalities. An MRI of the abdomen shows a tumor at the head of the pancreas with the appearance of a carcinoma. The patient declines all intervention. The initial manifestation of tumor growth in this patient will most likely be obstruction of which of the following?

Common bile duct

A 67-year-old man comes to the physician because he occasionally trips when he walks, especially when he is moving from the kitchen to the adjacent carpet living room. He says it is the right foot that seems to give him problems. Physical examination shows weakness on dorsiflexion and eversion of the right foot. The right ankle is normal bilaterally. Sensation to light touch and pinprick is decreased on the anterior aspect of the right lower extremity and the entire dorsum of the right foot; sensations on the left are normal. When asked to walk on his heels, he cannot lift his toes on the right side. Which of the following nerves is most likely affected?

Common fibular (peroneal)

A 3-year-old boy is brought to the emergency department by his mother because of a sore on his left foot 24 hours after stepping on a rotten piece of wood while walking barefoot. Physical examination shows a splinter embedded in the soul of the foot. The area around the splinter is warm, edematous, and there is possibly the wound. Which of the following mediators is most important in neutrophil chemotaxis towards the site of injury in this patient?

Complement

A 58-year-old man dies from heart failure that was refractory to therapy. At autopsy his heart weighs 490g. Sections of his heart are shown. Which of the following is the most likely diagnosis? Image 330

Congestive heart failure resulting from repeated infarcts

A 52-year-old woman with breast cancer comes to the physician for a follow-up examination. She had a 4-week course of radiation treatment 6 months ago. Her respirations are 26/min. Physical examinations show no recurrence of the cancer. A CT scan of the chest shows bilateral patches of atelectasis in the upper lung fields. The atelectasis in this patient most likely developed because of which of the following primary pathophysiologic processes?

Consolidation

A 37-year-old primigravid woman at 18 week's gestation comes to the physician with her husband for a follow-up visit. Ultrasonography at her last visit showed multiple fetal anomalies. Amniocentesis shows trisomy 13. The physician explains that the fetus will have multiple neurologic somatic defects and severe mental retardation; he notes that only 5% of those infants survive 3 years. The husband wants an elective abortion, but the patient is opposed to it. Which of the following is the most appropriate next step in management?

Continue routine prenatal care

A 19-year-old man is evaluated for signs of gastrointestinal bleeding. At lab, a 5-cm blind outpouching on the antimesenteric side of the terminal ileum, about 15 cm from the ileocecal valve, is resected. Pathologic examination of the resected segment will most likely show which of the following?

Crohn disease

A 52-year-old man who is in the hospital with malignant hypertension, heart failure, and a mild renal impairment is being treated with captopril, Nitroprusside, and furosemide. After 48 hours of therapy, his blood pressure is controlled, but he develops metabolic acidosis, lethargic, and difficult breathing which of the following substances most likely cause the adverse effects in this patient?

Cyanide

A 21-year-old man is brought to the emergency department 1 hour after the acute onset of left-sided chest pain and shortness of breath. The symptoms began while playing basketball with friends. He is 178cm tall and weighs 63kg; BMI is 20kg/m and pulse is 120/min, respirations are 30/min, and blood pressure is 124/86 mm Hg. Breath sounds are decreased on the left. There is hyper ressonance to percussion of the left hemithorax. A chest x-ray shows a sharp line adjacent to a radio lucent region without lung markings on the left side. Which of the following is the strongest predisposing factor for this patient's condition?

DUNNO A. Collision with another player B. Family history of asthma C. Gender and body habitus D. History of tobacco use E. Playing basketball

A 38-year-old woman has weakness and atrophy of the intrinsic muscles of both hands and decreased pain sensation in both upper extremities. Which of the following is the most likely cause of these findings?

Cystic lesion (syrinx) involving midline structures and both ventral horns in the cervical enlargement of the spinal cord

A previously healthy 55 year old man comes to the physician because of a 2 day history of pain and nausea. His temperature is 38.5 degrees Celsius (101.3 F), pulse is 88/min, respirations are 20/min, and blood pressure is 144/88 mm Hg. Physical examination shows acute low back tenderness. Urinalysis shows 3+ protein; numerous WBC's, epithelial, and bacteria; and a few RBCs. Treatment with a quinolone antibiotic is initiated, but his symptoms do not resolve. Urine culture grows Escherichia coli resistant to ciprofloxacin. The most likely cause of this resistance is a mutation in which of the following elements?

DNA gyrase

A 22-year-old woman with cystic fibrosis is brought to the emergency department because of progressive shortness of breath or 36 hours. She has a history of responding well to levofloxacin and aztreonam therapy. Her respirations are26/min. Bilateral coarse crackles and wheezes are heard on auscultation of the chest. Sputum cultures grow Pseudomonas aeruginosa. Despite treatment with levofloxacin and aztreonam, her condition does not improve. Laboratory studies show that the organism is highly resistant to levofloxacin. The most likely explanation for this resistance is a mutation of which of the following?

DNA topoisomerase II (DNA gyrase) and IV binding sites

An 18-year-old man comes to the physician because of non-pitting facial edema and difficulty breathing several hours after a dental procedure. He has a history of unexplained episodes of abdominal pain. His serum C2 concentration is found to be markedly decreased. Which of the following best explains this patient's illness

Decreased C1 esterase inhibitors

An 18-year-old woman develops sepsis after an abortion. Within 24 hours she becomes dyspenic, oliguric, and develops petechiae, ecchymoses, and bleeding from venipuncture site. Which of the following is the laboratory finding most consistent with this disease process?

Decreased plasma fibrinogen concentration

An un-immunized 15-month old boy who is infected with measles virus develops severe pneumonia and dies; he did not develop a maculopapular rash. Which of the following best explains this unusual course?

Defective T lymphocytes mediated immune response to measles virus

A 800-g (1-lb 12-oz) male newborn is delivered at 28 weeks' gestation to a 37-year-old woman, gravid 5, para 4. The mother had no prenatal care. His Apgar scores are 5 and 7 at 1 and 5 minutes, respectively. One hour after birth his pulse is 162/min, and respirations are 50/min. Physical examination shows cyanosis and retracting respirations with grunting and nasal flaring. Arterial blood gas analysis on 100% oxygen via nasal cannula shows a PCO2 of 50 mm Hg and PO2 of 53 mm Hg. He is intubated, and positive pressure ventilation is initiated. A chest x-ray shows diffuse consolidation. Administration of which of the following drugs to the mother during her pregnancy most likely would have decreased the likelihood of this newborn's condition?

Dexamethasone

A 1045 g (2-lb 5-oz) male newborn delivered at 28 weeks' gestation develops rapid breathing, grunting and subcostal retractions shortly after birth. Coarse rhonchi are heard on auscultation of the chest. A chest x-ray shows fine densities with a reticulogranular appearance bilaterally. Arterial blood gas analysis on room air shows decreased pH and Po2 and increased Pco2. A deficiency of which of the following is the most likely cause of the pulmonary disorder in this patient?

Dipalmitoylphosphatidylcholine

A 61-year-old woman is brought to the physician by her 62 year old husband because of a 9 month history of increasing forgetfulness. Her husband says "I'm worried because she forgets about dinner on the stove and its ends up being burned. Once she even left the bathtub running, and it overflowed and flooded the bathroom" He adds that she had always been a meticulous gardener, but now the flowerbeds have become uneven, with some of the areas flourishing and the others seemingly untouched. Physical examination shows no abnormalities. During the mental status examination the patient is pleasant and cooperative. She describes her mood and good. She admits to being forgetful and feels badly about upsetting her husband and burning the food so often. Her Mini-Mental status examination score is 22/30. Which of the following is the most appropriate pharmacist /therapy?

Donepezil

During an experimental study, skin lesions resulting from group A streptococcus are examined in laboratory mice. A researcher produces a knockout mouse that lacks cathelicidin, an antimicrobial peptide produced by keratinocytes and active against group A streptococcus bacteria. A standard inoculation of the bacteria is then administered to the knockout mouse along with several other wild type and heterozygous knockout mice. The maximal area of necrotic skin ulceration caused by the inoculation is measured in each mouse, and the following data are obtained. The wild-type mouse has a lesion area of 50mm2. Which of the following test mice is most likely to be the homozygous knockout lacking cathelicidin? Mouse Lesion Area (mm2) A. A 100 B. B 50 C. C 30 D. D 25 E. E 0

Dunno

A 49-year-old man comes to the physician because of increasingly severe pain in his left hip during the past two months. He was recently discharged from a rehabilitation facility for treatment of alcoholism. He says "the pain gets so bad at times that it even hurts my golf game." He has pain with weight-bearing. Physical examination shows limited active and passive range of motion of the left hip. Hip x-rays showed no abnormalities. A coronal t1- weighted MRI is shown. Which of the following is most likely cause of this patient's pain? IMAGE

Dunno A. Avascular necrosis B. Hyperparathyroidism C. Osteitis deformans D. Septic arthritis E. Tuberculous osteomyelitis

A 23-year-old man is admitted to the hospital because of the tachypnea, dyspnea and increasing cyanosis. He aspirated gastric contents when vomited at a party the previous evening. An x-ray of the chest shows bilateral interstitial and terminal air space infiltrates. Which of the following is the most likely cause of the respiratory distress?

Fluid exudation in alveolar spaces

A 19-year-old woman with a 3-year history of type 1 diabetes mellitus is brought to the emergency department at 2:00 PM because of the confusion and tremulousness for the oast 30 minutes. She forgot to eat lunch after injecting her usual morning insulin dose. Serum glucose concentration is 24 mg/dL. Which of the following substances is also likely to have a low serum concentration in this patient?

Glucagon

A 70-year old man dies of coronary artery disease. He had a cerebral infarction 8 years ago. A photograph of a specimen of the brain stem is shown. Which of the following neurological deficits was most likely present in their patient after his cerebral infarction? Image on 388

Going to have to figure it out!

A 27-year old woman comes to the physician because of fever, malaise, abdominal pain, and vaginal discharge for 4 days. Her last menstrual period ended 5 days ago. She had an ectopic pregnancy 1 year ago. Her temperature is 38.3°C (101°F). Abdominal examination shows cervical motion tenderness. Her leukocyte count is 18,000/mm3. A pregnancy test is negative. Which of the following is the most likely diagnosis?

Gonorrhea

A 5-year-old girl with premature sexual development is diagnosed with precocious puberty. Pelvic examination shows a mass consistent with an ovarian tumor. Laboratory studies show decreased serum concentrations of gonadotropins and a marked increase in circulating estrogens. The ovarian tumor is most likely derived form which of the following cell types?

Granulosa cells

A 57-year-old man with alcoholism has a distended abdomen with shifting dullness and a fluid wave. He was caput medusa, palmar crythema, and spider angiomata. Which of the following is the most likely additional finding?

Gynecomastia

A 39-year-old man who is HIV positive comes to the physician because of painful swallowing for 2 weeks. He does not have hematemesis or melena. Examination of the oral cavity shows no lesions. Upper gastrointestinal endoscopy shows three ulcerations of the upper and mid esophagus ranging from 0.3 to 0.8 cm in diameter. The shallow ulcers are sharply demarcated and involve only the mucosa. Microscopic examination of biopsy specimens from the ulcer edges shows multinucleated cells with mauve-to-pink intranuclear unclusions. Which of the following viruses is the most likely cause of these findings?

Herpes Simplex Virus

A 34-year-old man with a 4-year history of AIDS comes to the physician because of the formation of irregularly shaped lesions on his foot as shown. Which of the following is the most likely causal organism? Image on 331

Herpes virus 8

A 40-year-old woman is brought to the physician by her husband because of a 3-year history of memory problems and decreased cognitive function. She has had personality changes including irritability, impulsiveness, and ____ during this period. Neurological examination shows irregular jerking movements of the upper and lower extremities. An MRI of the brain shows atrophy of the striatum. Which of the following is the most likely diagnosis?

Huntington disease

An autopsy, the heart of a 76 year old woman shows concentric enlargement of the left ventrile. Microscopic examination of the heart shows enlarged myocardial cells with large nuclei. Which of the following diseases was the most likely cause of the cardiac enlargement?

Hypertension

An 8-year-old boy with severe mental retardation is brought to the physician because of a 1-year history of self-mutilating behavior, including biting his fingers. His cousin has similar symptoms. Physical examination shows spasticity, chorea, and mutilation of the fingers, He is individual III-1 in the pedigree shown. This patient most likely has a deficiency of which of the following enzyme activities?

Hypoxantina-guanine-phosphoribosyltransferase

A 68-year-old man develops acute abdominal distention and severe abdominal pain. The abdomen is_______ to percussion, and high-pitched tinkles are audible on auscultation and all for abdominal quadrants. An abdominal x-ray shows dilated loops of small intestine that contain air fluid levels. There is visible in the right scrotal sac. Which of the following is most likely diagnosis?

Incarcerated hernia

A 21 year old man comes to the physician because of intermittent episodes of light brown urine during the past year associated with upper respiratory tract infections. His blood pressure is 145/85 mm Hg. Physical examination shows the other abnormalities. Urinalysis shows no other abnormalities. Urinalysis shown microscopic blood, 3+ protein, and several RBC casts. Immunohistochemical staining of a renal biopsy specimen is most likely to show granular deposits in the glomerular mesangium predominantly consisting of which of the following immunoglobulins?

IgA

A 54 year old woman has a recently diagnosed occlusion of the superior mesenteric artery near its origin. If significant collateral circulation is not present or fails to develop, she will have an increased risk for ischemia in which of the following parts of the gastrointestinal tract?

Ileum

A 50-year-old man who smokes two packs of cigarettes a day for 34 years has experienced gradually increasing shortness of breath on exertion, chronic cough productive of thick sputum, and frequent episodes of wheezing. The anterposterior diameter of his chest is increased. Diminished breath sounds and scattered rhonchi are audible throughout the lung fields. Which of the following laboratory anomalies is expected?

Increased blood HCO3

A 63-year-old man comes to the physician because of a 3-month history of difficulty sleeping. He indicates that he sleeps better if he sits upright in bed. His pulse is 90/min, and blood pressure is 110/60 mm Hg. Physical examination shows increased jugular venous pressure and mild ankle edema. Which of the following is the most likely cause of the edema in this patient?

Increased capillary hydrostatic pressure

A 78-year-old man _________ his daughter because of low_____three months. He underwent bilateral____ two years ago for prostate cancer. He speaks French fluently, but he knows only a few English words. His daughter offers to serve as a interpreter. After thinking the daughter for her offer, it is most appropriate for the physician to state which of the following?

It is best that I use a professional French interpreter

A 75-year-old man comes to the physician because of a 2-year history of decreased force of his urinary stream and a need to urinate several times throughout the night. His serum urea nitrogen (BUN) concentration is 55mg/dL, and serum creatinine concentration is 5.0mg/dL. Ultrasonography of the unrinary tract shows bilaterally hydronephrosis and dilated ureters. Which of the following is the most likely mechanism of this patient's renal failure?

Increased hydrostatic pressure in Bowman space

A 3 year old boy who recently immigrated to the USA is brought to the physician by his parents because of skeletal deformities and failure to thrive. He has had listlessness, irritability, and muscle weakness most of his life. Physical examination shows frontal bossing and flattening of the back of the skull, and defects in the enamel of the teeth. The chest wall has a groove that extends from the xiphoid process transversely toward the axillae, with flaring of the rib cage below the groove. The sternal ends of the ribs bulge at their costochondral junctions. The legs are bowed. Serum calcium and phosphorus concentrations are below the reference range. If the bone were examined, which of the following findings would be most likely?

Increased proportions of osteoid

A patient with supraventricular tachyarrhythmia may benefit from an increase in vagal stimulation to the heart because of which of the following effects?

Increased refractory period of the AV node

A 52-year-old woman has excessive thirst and frequent urination. There is no detectable glucose in the urine. All water is withheld for 6 hours. Which of the following findings is most consistent with the diagnosis of nephrogenic diabetes insipidus?

Increased serum ADH (vasopressin) concentration

A 32-year-old man with schizophrenia, undifferentiated type, is brought to the emergency department by his father at 9:00 PM because of increasing confusion and muscle stiffness over the past 12 hours. He takes haloperidol (5 mg twice daily) and benztropine (1 mg twice daily); his last dosage of medication was this morning. On arrival, his temperature is 38.9 C (102 F), pulse is 96/min and blood pressure is 150/92 mm Hg. He is mute and appears lethargic. Examination shows muscle rigidity in all extremities. Which of the following is most likely laboratory finding in the patient?

Increased serum creatinine kinase activity

A 27-year-old woman is brought to the emergency department 30minutes after she was ejected through the windshield during a motor vehicle collision. She was the unrestrained front-seat passenger. Physical examination shows marked edema and tenderness of the jaw. A Panorex x-ray of the mouth is shown. Which of the following additional structures is most likely injured by this abnormality? IMAGE

Inferior alveolar nerve

A 15-year-old man is brought to the physician two days after the onset of double vision and drowsiness. Three weeks ago, he began using over-the-counter cimetidine for dyspepsia. He has epilepsy treated with phenytoin for the past two years. Physical examination shows nystagmus and an ataxic gait. Which of the following effects of cimetidine on phenytoin is the most likely cause of the adverse effects in this patient?

Inhibition of metabolism

A 5-year-old boy who is HIV-positive is brought to the physician by his mother for an examination before starting kindergarten. His mother says, " he's never been in school before. Do I have to inform the school that he is HIV-positive?" Vital signs are within normal limits physical examination shows no abnormalities. Which of the following initial statements by the physician is most appropriate?

It's up to you. The school should already have universal precautions related to blood-borne infections in place THIS FEELS WRONG

A 67 year old man with hypertension is brought to the emergency department because of the sudden onset of a headache followed by right-sided paralysis. He is unable to speak. Five minutes later, his left pupil dilates to 7 mm and is unresponsive to light. Soon thereafter, he develops bilateral decerebrate posturing. Which of the following is the most likely cause of his condition?

Lacunar infarction

A 49-year-old woman comes to the physician because she had a lump in the lower inner quadrant of her right breast for the past month. The mass is hard and appears to be fixed to the underlying musculature. Histological examination of the exercise 2.1 cm mass shows tumor cells infiltrating the breast tissue and chords and tubules. The cells are small with hyperchromatic nuclei and occasional mitoses. Occasional invasion into lymphatics is seen. Tumor cells are found in one of the four lymph nodes examined. Which of the following characteristics is most useful in defining the stage of the tumor?

Invasion of lymphatics

A 16-year-old boy is brought to the physician by his father because he has no signs of puberty. Sexual development is Tanner stage 2. Physical examination shows a circumcised penis. The testes are soft and small with a volume of 5 mL (N=20-30). The prostate is firm, nontender, and of appropriate size. There are no lesions or discharge. His serum testosterone concentration is in the prepubertal range. Measurement of which of the following hormones in serum is most likely to determine whether the decreased serum testosterone concentration is a result of a lack of pituitary hormone stimulus in this patient?

LH

Investigators are interested in comparing the mortality rate in different parts of the country. They use raw (unadjusted) vital statistics to compare mortality rates in the Northeast, Southeast, Midwest, Southwest, and Northwest USA. They find significant (p<0.05) differences in mortality rate by region and conclude that some regions of the country have more toxic environments than others. Which of the following raises the most concern about the validity of this conclusion?

Lack of randomization

A 40-year-old man comes to the physician because of a 2-month history of lethargy. He is employed as a biochemist as a local food processing plant. In college, he worked as a laboratory assistant in a perfume factory and was exposed to various hydrocarbons, including benzene, for 4 years. This occupational exposure increases his risk for which of the following?

Leukemia

A 6-year-old boy is brought to the physician because of a 1-year history of stereotypical blinking, facial grimacing and shoulder shrugging. The symptoms have been occurring several times a day and are somewhat accompanied by snorting noises. When asked by the physician, the patient voluntarily suppresses the movements for a few seconds. After 5 seconds, he has a rebound burst of exaggerated movements. Which of the following is the most likely comorbid disorder in this patient?

Obsessive-Compulsive disorder

A 25-year-old woman at 38 weeks's gestation undergoes an oxytocin stress test to evaluate the integrity of the placental circulation. Based on the results, a full-scale induction of labor with oxytocin is started. Treatment with oxytocin is most likely to active which of the following substances in this patient's uterine smooth muscle

Ligand-gated calcium channels

A 35-year-old man with Chagas disease comes to the emergency department because of a 2-hour history of moderate chest pain. He has had a 2-kg (4.4-lb) weight loss during the past 2 months. His pulse is 100/min, respirations are 25/min, and blood pressure is 135/90 mm Hg. An ECG shows no abnormalities. A barium swallow shows a dilated esophagus with beak-like narrowing sphincter (LES). A biopsy specimen of the LES is most likely to show which of the following?

Loss of neurons in the myenteric plexus

During an experiment an investigator isolates an annormal elastin with unusual instability from the connective tisse of mice. Analysis of the elastin shows a decreased number of desmosine cross-links. Upon amino acid analysis, the concentration of which of the following amino acids in the abnormal protein would be most likely different when compared with normal elastin?

Lysine or Proline

A 4 year old boy with chronic granulomatous disease is brough to the physician by his parents for a follow-up examination. He has a 2-year history of recurrent catalase positive fungal and bacterial granulomatous infections that have been inconsistently responsive to trimethoprimsulfamethoxazole, dicloxaciltin, and itraconazole. Physical examination shows no additional abnormalities. Treatment with interferon gamma is begun. Activity of which of the following cells is most likely to be significantly increased in this patient after exposure to this drug?

Macrophages producing IL-1

A 75-year-old woman falls and fractures her hip while getting out of a car. Laboratory's studies inlude: Serum Calcium 9.5 mg/dL Phosphate 4.0 mg/dL Alkaline phosphates 50U/L Urea nitrogen (BUN) 10mg/dL Which of the following bone disorders is most likely to have predisposed to the hip fracture?

Osteoporosis

1-year-old girl is brought to the physician because of a 5-day history of lethargy, fever, cough, runny nose, and puffy red eyes and a 1-day history of rash. Physical examination shows a temperature of 40°C (104°F), a confluent maculopapular rash, conjunctival injection, a mucopurulent nasal discharge, an erythematous pharynx, and many small, irregular rose-red spots with a bluish white speck in the center on the buccal mucosa. The most likely cause of her condition is infection with which of the following viruses?

Measles virus

A 28 year old woman is unable to oppose her thumb after accidentally cutting her wrist. Which of the following nerves was most likely injured?

Median

A 40 year old woman comes to the physician because of a 6 month history of dryness of her mouth and itching and burning of her eyes. Physical examination shows inflammation of both corneas and sclerae, enlarged salivary glands, and a paucity of saliva. Serum antinuclear antibody assay is positive. She is told that she is at risk for developing a lymphoma. Which of the following is the most likely mode of inheritance?

Multifactorial

A 60-year-old man comes to the emergency department because of the sudden onset of acute abdominal pain and tenderness, nausea, vomiting, and bloody diarrhea 2 hours ago. He has a history of cirrhosis and hepatocellular carcinoma. His blood pressure is 99/50 mm Hg. His abdominal wall becomes rigid, with the loss of bowel sounds. During surgical intervention, half of the small intestine is found to have a dark purple-red hemorrhagic appearance. Which of the following is the most likely cause?

Mesenteric venous thrombosis

51. A 34-year-old woman has nonexcertional chest pain and palpitations. She has had repeated episodes of anxiety over the past 6 months. She has a midsystolic click. Echocardiography is most likely to show which of the following?

Mitral valve prolapse

An investigator is recording the amplitude of the end plate potential (EPP) in a single striated muscle fiber on stimulation of the motor nerve. The graph shows the frequency distribution for EPP's of various amplitudes for all to stimuli that produce a response. Which of the following shows the correct rank order for mode, median, and mean values from the smallest to largest? GRPAH

Mode < Median < Mean

A 20-year-old woman comes to the student health clinic because of a fever and a constant, hacking, nonproductive cough for the past 2 weeks. She has also had shortness of breath when climbing stairs during the same time. Temperature is 39.5°C (103.1°F). Crackles are heard through the right lung field. X-ray of the chest shows increased interstitial markings in the right middle and lower lobe. Which of the following is the most likely causal organism?

Mycobacterium TB

A 22-year-old man comes to the emergency department 30 minutes after he sustained a 15-cm laceration of his right arm. The wound is sutured. Eight weeks later, there is a well-healed scar. Which of the following cells is the most likely cause of the wound contracture in this patient?

Myofibroblast

A 51-year-old man has a cardiac output of 5L/min and a right atrial pressure of 0mm Hg at rest. The solid curve in the graph shows the relationship between right atrial pressure and cardiac output in a normal heart. Which of the following letter points best represents the change in this relationship, 5 seconds after a large arteriovenous fistula opens? GRAPH

NO IDEA

A 56-year-old man with a 20-year history of chronic back pain undergoes operative placement of an electrode in his midbrain for pain management. Previous physical and neurological examinations showed no abnormalities. When the implant is activated, the patient reports a marked decrease in pain. Administration of which of the following substance would most likely result in the return of the patient's pains?

Naloxone

A 74-year-old man with emphysema and lung cancer is brought to the clinic by a social worker because of his wasted appearance. His wife of 50 years died eight months ago. He is impoverished, and his diet consists primarily of cereal and toast. He has lost 13.6 kg(30lbs) in the past six months. He has temp oral muscle wasting, sunken eyes, loose skin, and edema of the lower extremities. He appears despondent and withdrawn. Serum albumin concentration is 2.5 g/dL. An x-ray of the chest shows a large mass in the hilum of the right lung. Which of the following best explains the edema?

Negative nitrogen balance

A 23-year-old man begins a weight-lifting regimen three times weekly. After 6 months, he has an increase in the size of his skeletal muscle fibers. Which of the following best explains this finding?

New myofibrils within the cell

Following a wedding reception that was attended by 75 people, 25 adults develop low-grade fever, of abdominal cramping, vomiting, and diarrhea. The symptoms began 24 to 36 hours after the event and resolve without treatment in 3 to 4 days. Studies of stool specimens from several of the patients showed no occult blood; No leukocytes are seeing on microscopic examination, and stool cultures grow on no pathogens. Several family members exhibit similar symptoms three days after the initial outbreak. Which of the following is most likely casual organism?

Norovirus

A three-month-old girl is admitted to the hospital for operative repair of a hernia. Physical examination shows bilateral inguinal hernias and normal external genitalia. During the operation bilateral testes and a line ending vagina are found, and internal genitalia are absent. Chromosomal analysis indicates a 46,XY karyotype. These findings are most likely due to a mutation in the gene that encodes which of the following types of receptors?

Nuclear

A patient cannot see a test object placed in the left visual field of the left eye or the right visual field of the right eye. The most likely cause is a lesion in which of the following parts of the visual pathway?

Optic chiasm

Astronauts exposed to zero gravity for up to 1 year show negative calcium balance throughout the space flight. Which of the following descriptions of cellular activity is the most likely explanation for these findings?

Osteoclast is greater than osteoblast

A 30 year old woman has several tan papules on the dorsal surface of her left hand. Examination of tissue obtained on excision of a papule shows verrucous epidermal hyperplasia with koilocytosis in the superficial epidermal layer. Which of the following viruses is the most likely cause of this benign proliferation?

Papillomavirus

During evalution for infertility, a 30 year old woman is found to have a bicornuate uterus with a midline ulterine septum. The septum represents an abnormal remnant of which of the following?

Paramesonephritic ducts

A 70-year-old man is brought to the physician by his daughter because of the progressive onset of confusion over the past year. His daughter says, "He forgets the names of his friends and is always leaving the faucet running or the TV on. He's been so much slower doing anything for the last couple of year compared with the past." His pulse is 68/min and regular, and blood pressure is 126/74 mm Hg. His voice is soft, and his posture is stooped. His pupils are equal in size, round, and reactive to light. His muscles are hypertonic. He has a resting tremor bilaterally. There is intermittent resistance when the physician moves one arm from maximal flexion to maximal extension. He walks with a shuffling gait. Which of the following is the most likely diagnosis?

Parkinson's disease

Following an operation, a 65-year-old patient as a long region that is under ventilated but well perfused. This condition will lead to an increase of which of the following?

Physiologic shunt

A 35-year-old primigravid woman at approximately 36 weeks gestation comes to the emergency department because of a six-hour history of heavy vaginal bleeding. She has had no prenatal care. Ultrasonography shows that the placenta is located over the cervical os. Attempts to stop the bleeding or unsuccessful, and she undergoes a cesarean Delivery. Which of the following is the most likely diagnosis?

Placenta previa

After sustaining nonpenetrating trauma to the chest in an automible accident. a 20 year o.man has tachypnea and dyspnea. Examination shows decreased breath sounds, hyperresonace to percussion, , and decreased diaphragmatic to percussion, , and decreased diaphragmatic excursions, all on the right . X-ray of the chest is most likely to show which of the following?

Pneumothorax

A 53-year-old man comes to the physician because of a 6-day history of shortness of breath, cough, and pleuritic chest pain. His temperature is 38.9C (102 F), and respirations are 35/min. sputum is purulent and rust colored. Physical examination shows decreased breath sounds, and crachles are heard at the left base. A gram stain of sputum shows gram-positive diplococcic. A chest x-ray shows left-sided lobar consolidation. Which of the following anatomic structures most likely allowed rapid spread of organisms between alveoli to involve the entire left love in this patient?

Pores of Kohn

A 50-year-old man develops shortness of breath 3 days after starting a new medication. Forced vital capacity maneuvers before and after starting the drug are shown in the graph. The patient is most likely taking which of the following drugs? GRAPH

Pronanolol

29-year-old woman comes to the physician because of irregular menstrual periods since menarche at the age of 12 years. She is evaluated, and the diagnosis of polycystic ovarian syndrome is made. After explaining the diagnosis, the physician discusses behavioral changes, including dietary modification and exercise as part of her treatment plan. Which of the following is most likely to result in patient adherence to this plan?

Provide follow-up appointments to assess the patient's progress in attaining her goals

A 66-year-old man comes to the physician because of a two month history of inability to achieve an erection since starting a new relationship. He has had spontaneous nocturnal erections during this period. He had sexual intercourse 1 to 2 times weekly until his wife of 40 years died eight months ago. His pulse is 72/min, an blood pressure is 128/74 mm Hg. Physical examination shows 2/4 femoral pulses without bruits and 2/4 dorsalis pedis and posterior tibial pulses bilaterally. Deep tendon reflexes are 2/4 with a normal relaxation phase. Which of the following is most likely cause of erectile impotence in this patient?

Psychogenic factors

A 70-year-old man is admitted to the hospital for evaluations of the recent loss of mental function. He has a history of weight loss. He is not taking any drugs. Vital signs are normal, and he is not he hydrated. Aside from mild disorientation, findings on neurological examination are unremarkable. He has mild anemia. Laboratory studies show: Serum NA 110mEq/L Cl 85mEq/L K 4.4 mEq/l Urea Nitrogen (BUN) 15 mg/dL Creatinine 0.9 mg/dL Plasma osmolarity 250 mOsmol/kg Urine osmolarity 750 mOsmol/kg Which of the following is most likely diagnosis?

Pulmonary neoplasm

Feedback inhibition of the activity of the enzyme that catalyzed this reaction is critical in the control of the de novo synthesis of which of the following? Diagram on image 484

Pyrimidine nucleotides

A 2296-g (5-lb 1-oz) female newborn delivered to and 18 year old primigravid woman after a vaginal delivery. The mother had no prenatal care. Examination of the newborn showed jaundice. Laboratory studies show severe ______ with evidence of hemolysis and hyperbilirubinemia. The newborn has Rh-positive erythrocytes: the mother is Rh-negative. Administration of which of the following to the mother during the pregnancy most likely would have prevented this complication in the newborn?

Rh 0(D) immune globulin

Persons at risk for severe influenza are vaccinated every year because of antigenic variation. This variation can be ether a result of antigenic drift (minor) or antigenic shift (major) changes in the antigenic composition of viral proteins. Which of the following is the most likely genetic mechanism of the antigenic shift?

Reassortment

A 71-year old man sleeps only 5 hours per night. Although he feels rested, he is concerned that he is not getting enough sleep. Which of the following is the most appropriate action?

Reassure him that 5 hours of sleep is probably normal for him

A 50 year old woman comes to the physician requesting botulinum toxin type A treatment for her facial wrinkles. Physical examination shows wrinkles in the forehead and at the corners of each eye. Botulinum toxin is administered to these areas. Blockade of which of the following is most likely to occur in this patient?

Release of neurotransmitter from axon terminals

Based on the graph of p-aminohippurate (PAH) concentration versus PAH secretion, which of the following is lower at point Y than at point X? image 284

Renal blood flow

A 25 year old man comes to the physcician because of a 2 month history of persistent headaches. He has a family history of retinal hemangioblastoma, pancreatic cysts, and renal tumors. Funduscopic examination shows bilateral papilledema. MRI of the brain shows a midline cerebellar tumor that is found to be a cerebellar hemangioblastoma. This patient is at risk fr developing which of the following types of tumors?

Renal cell carcinoma

A healthy 40-year-old man is participating in a study in which he is given an intravenous injection of insulin to induce hypoglycemia. The graph shows serum concentrations of catecholamines act baseline and the peak values at the nadir of serum glucose. Which of the following most likely underlies the different magnitude of the epinephrine and norepinephrine responses? GRAPH

Reuptake of norepinephrine into sympathetic synapsis

A 32 year old man with HIV infection comes to the physician for a follow-up examination. He has been treated with highly active antiretroviral therapy (HAART) for the past 6 years during which time his plasma HIV viral load has been undetectable. His plasma HIV viral load has now increased, and antiretroviral resistance is suspected. HIV genotype analysis confirms that the virus has resistance mutations. Based on this finding, which of the following are most likely mutated?

Reverse transcriptase and protease

A 25-year-old woman comes to the physician because of a 6-month history of joint pain that has been poorly responsive to treatment with aspirin. Physical examination shows bilateral swelling of the proximal interphalangeal joints, metacarpophalangeal joints, and the wrists; there is weakness of grasp. A few small nodules are palpated beneath the skin around the joints of the fingers. Which of the following is the most likely diagnosis?

Rheumatoid arthritis

A neoplasm in the apical region of the left lung blocks the thoracic duct in the base of the neck. From which of the following structures will lymph continue to flow along its normal, unaltered pathway?

Right breast

A 60-year-old man is brought to the emergency department after being thrown from his car and striking a guardrail in a high-speed automobile collision. He was the unrestrained driver. Physical examination shows blood at the urethral meatus and fractures of the pelvis and the left femur. A Foley catheter is unable to be inserted. Which of the following is the most likely explanation?

Ruptured bladder

An 18 year old woman receives general anesthesia for extraction of wisdom teeth. After 5 minutes, she has generalized hypertonicity of skeletal muscles and increased body temperature. The most appropriate treatment is a drug that decreases which of the following?

Sarcoplasmic Ca2+ release

A full term newborn has respiratory distress. Imagining studies show herniation of abdominal contents into the left pleural cavity. Maldevelopment of which of the following structures is most likely to have cause the defect of the diaphragm?

Septum transversum

A 2950-g (6-lb 8-oz) female newborn is delievered at 38 weeks' gestation. Physical examination shows a patch of hair on the midback at midline and localized discoloration of the skin. There are no abnormal neurologic findings. An MRI of the spine shows absence of the spinous processes but an intact dural sheath. Which of the following is the most likely diagnosis?

Spina bifida

A 20-year old man comes to the emergency department because of a 12 hour history of fever and chills after he injured his right thigh shows warmth, edema, and tenderness. There are abrasions and two deep puncture wounds. He leaves against medical advice without treatment. Three weeks later, he is brought to the emergency department because of a 12 hour history of fever and right leg pain. Blood cultures are negative. An x-ray of the right thigh shows irregular areas of cortical lucency in the femoral diaphysis adjacent to a nondisplaced fracture. Which of the following is the most likely casual organism?

Staph Aureus

A 25-year-old man comes to the physician because of a 6-week history of daytime fatigue, irritability, and emotional liability; he has had 4.5-kg (10-lb) weight loss during this period. He says that he is sleep-deprived, but he is unable to fall asleep readily. He is a medical student and has recently finished an intensive care unit notation where he often worked days and nights. He currently on an outpatient rotation and will be starting vacation next week. Physical examination shows no abnormalities. Which of the following recommendations by the physician is most appropriate to improve this patient's sleep hygiene?

Stay in bed, even if you can't fall asleep OR Try getting up the same time every day, even if you didn't get much sleep

A 60-year-old woman is being treated for primary hyperparathytoidism. She has an increased serum calcium concentration and a decreased serum phosphate concentration. A Ct scan of the neck shows an enlarged mass in the lower left pole of the thyroid gland. During surgical resection of the neoplasm, the three other parathyroid glands appear small and atrophic. Examination of tissue obtained on excision of the neoplasm shows parathyroid adenoma. Which of the following in the most likely explanation for the appearance of the three remaining parathyroid glands?

Stenosis of the inferior thyroid artery

A 25-year-old woman is admitted ot the hospital because pf septic shock. She underwent splenectomy 6 months ago after she sustained traumatic injury during a motor vehicle collision. Her temperature is 39.4°C (103°F), and blood pressure is 80/40 mm Hg. Coarse tubular breath sounds are heard bilaterally and egophoney is heard at the right base. A chest x-ray shows bilateral pulmonary opacities, dense consolidation at the base of the right lung and a possible right-sided effusion. Which pf the following is the most likely causal organism?

Strep pneumoniae

A 65 year old man who recently emigrated from Brazil comes to the physician because of an 8 month history of shortness of breath and fatigue. Physical examination shows edema of the lower extremities. A chest x-ray shows cardiomegaly. AN endomyocardial biopsy specimen shows individual myofiber necrosis with a mixed inflammatory infiltrate of neutrophils, T lymphocytes, macrophages, and eosinophils. Which of the following is the most likely causal organism?

Trypanosoma cruzi

A 45 year old woman with chronic myelogenous leukemia comes to the physician for a follow up examination. Physical examination shows pallor and bleeding gums. Laboratory studies show a leukocyte count of 90,000/mm^3 (60% blasts) and a platelet count of 27,000/mm^3. A drug regimen of mitoxantrone, vinblastine, and thioguanine is initiated, with no improvement. During the last cycle of scheduled treatment, a sample of the blast cells is harvested, and the intracellular concentrations of mitoxantrone and vinblastine in these blast cells are found to be undetectable. An increase in which of the following mechanisms best explains this observation?

Thiopurine methyltransferase activity in the leukemic cells

A 6 month-old girl is brought to the physician by her parents because of irritability and frequent crying during the past 2 weeks. Her mother says "Sometimes when she's not crying, she gets very quiet and it seems like she's not breathing. Physical examination shows prominent scalp veins in the frontal region and mild buldign of the anterior fontanel. An MRI of the brain shows stenosis of the cerebral aqueduct. Cerebrospinal fluid flow is most likely prevented between which of the following structures in this patient?

Third and fourth ventricles

A 27-year-old woman comes to the physician because of vaginal bleeding for 3 weeks. Her first pregnancy ended with a spontaneous abortion 8 months ago. She has not been able to afford medical treatment since undergoing dilation and curettage at that time. Physical examination shows an enlarged uterus. Her serum β-human chorionic gonadotropin concentration is markedly increased. Ultrasonography of the pelvis shows materials within the endometrial cavity and no intrauterine pregnancy. A CT scan shows a necrotic intrauterine mass and metastatic nodules in the lungs. Which of the following is the most likely site of origin of this patient's condition?

Trophoblastic tissue

A 6-year-old boy is brought to the physician because of a 2-year history of progressive stiffness and difficulty walking. Physical examination shows dystonia of the lower extremities. And MRI of the brain shows no abnormalities. In lumbar puncture is done. Cerebrospinal fluid analysis shows a markedly decrease homovanillic acid concentration. A deficiency of which of the following enzymes is most likely to cause this patient symptoms?

Tyrosine hydroxylase

A 40 year old man is drowsy and uncooperative and has involuntary rapid movements in both eyes for 2 weeks. He cannot remember what day it is or what he has been doing for the week. Deficiency of which of the following vitamins is most likely to cause this syndrome?

Vitamin B1 (thiamine)

A 42-year-old woman comes to the physician for a follow-up examination. She has a 22-year history of major depressive disorder. She shows the physician a letter from her insurance company stating that phenelzine, which she has taken for the past 10 years to treat her condition, will no longer be covered under her pharmacy's benefit plan. The letter states that she will need to speak with her doctor about prescribing a different medication. During the first 10 years of the patient's care, she failed to respond to many other antidepressants and was admitted to the hospital for depressive episodes on several occasions, she attempted suicide twice. Since starting phenelzine therapy, her symptoms have improved and she has been able to maintain a job and get married. The patient asks the physician what should be done in light of this new information. Which of the following responses by the physician is most appropriate?

We will file an appeal to your insurance company explaining why you need this medication