NBME Or National Board Of Medical Examiners Trivia Quiz

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NBME Or National Board Of Medical Examiners Trivia Quiz - Quiz

Are you preparing for your medical exam? How good are you with diagnosis and medications? Do you know what drugs are prescribed when someone is diagnosed with advanced cervical cancer? Check out the online quiz to test your knowledge and learn more.


Questions and Answers
  • 1. 

    A 2-year old girl takes oral cephalexin for treatment of Impetigo caused by group A beta-hemolytic Streptococcus, Which of the following is the mechanism of action of this antibiotic in this patient?

    • A.

      Binding to bacterial 30S ribosomal subunits

    • B.

      Binding to bacterial 50S ribosomal subunits

    • C.

      Inhibition of bacterial dihydrofolate reductase

    • D.

      Interference with bacterial cell wall synthesis

    • E.

      Production of beta-lactamase

    Correct Answer
    D. Interference with bacterial cell wall synthesis
    Explanation
    Mechanism of the antibacterial effect
    - It is due mainly to the two following actions:
    1) Beta-lactam antibiotics bind to specific beta-lactam receptors called penicillin-binding proteins (PBPs) located on the cytoplasmic membrane. These proteins are enzymes endowed with various catalytic functions which are inhibited by the binding with the
    antibiotic. The most important enzymes inhibited are transpeptidases which catalyze the
    final cross-link step in the synthesis of murein (also called peptidoglycan ). Since peptidoglycan layers are constituents of bacteria cell wall, the ***synthesis of this wall is blocked.***
    2) Autolytic enzymes (called autolysins or murein hydrolases) are present in the cell wall and degrade the peptidoglycan. Beta-lactam antibiotics can activate these autolysins (apparently by blocking an autolysin inhibitor) so promoting the lysis of bacteria.

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  • 2. 

    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.

      Activation of hepatic adenylyl cyclase

    • B.

      Activation of muscle glycogen synthase

    • C.

      Activation of muscle phosphorylase

    • D.

      Activation of muscle protein phosphatase

    • E.

      Inhibition of hepatic protein kinase A

    Correct Answer
    A. Activation of hepatic adenylyl cyclase
    Explanation
    Activation of hepatic adenylyl cyclase leads to increased levels of cyclic adenosine monophosphate (cAMP) in the liver. This activates protein kinase A (PKA), which in turn phosphorylates and activates hepatic glycogen phosphorylase. Activated glycogen phosphorylase breaks down glycogen into glucose, leading to an increase in blood glucose concentration. Therefore, activation of hepatic adenylyl cyclase is the most likely cause of this patient's hyperglycemia.

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  • 3. 

    A 50-year old man comes to the physician because of a 2-month history of pain in his wrists, changes in skin color, and progressive fatigue. His brother has type 2 diabetes mellitus and cirrhosis. Physical examination shows bronze-colored skin, tenderness of the metacarpophalangeal joints in both hands, and hepatosplenomegaly. Serum studies show: AST 100 U/L ALT 110 U/L Ferritin 1200ng/mL Total iron-binding capacity 200ug/dL (N=250-400) Transferrin saturation 80% (N=20-50) Analysis of a liver biopsy specimen shows a markedly increased iron concentration and cirrhosis. Which of the following is the most likely cause of the findings in this patient?

    • A.

      Ncreased erythropoietin action

    • B.

      Increased intestinal iron absorption

    • C.

      Increased oral iron intake

    • D.

      Decreased erythropoiesis

    • E.

      Decreased iron excretion

    • F.

      Decreased serum transferrin concentration

    Correct Answer
    B. Increased intestinal iron absorption
    Explanation
    The patient's presentation of bronze-colored skin, hepatosplenomegaly, and increased iron concentration in a liver biopsy specimen is consistent with hemochromatosis. Hemochromatosis is a genetic disorder characterized by increased intestinal iron absorption, leading to iron overload in the body. The increased iron absorption results in iron deposition in various organs, including the liver, causing cirrhosis. The elevated ferritin levels and transferrin saturation also support the diagnosis of hemochromatosis. The patient's family history of cirrhosis and type 2 diabetes mellitus further suggests a hereditary form of hemochromatosis.

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  • 4. 

    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.

      Absence of perfusion in some areas that are ventilated

    • B.

      Absence of ventilation in some areas that are perfused

    • C.

      Absence of ventilation-perfusion mismatching

    • D.

      Decreased perfusion gradient from the apices to the bases of the lungs

    • E.

      Increased ventilation-perfusion ratios at lung bases compared with those at apices

    Correct Answer
    A. Absence of perfusion in some areas that are ventilated
    Explanation
    The patient's symptoms of sudden onset right-sided chest pain and shortness of breath, which worsens with inspiration, along with a clear lung auscultation, are suggestive of a pulmonary embolism. In a ventilation-perfusion lung scan, a pulmonary embolism would present as an absence of perfusion in some areas that are ventilated. This occurs because the blood flow to those areas is blocked by a clot, leading to a ventilation-perfusion mismatch. This finding is consistent with the patient's symptoms and clinical presentation.

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  • 5. 

    A 25-year old man is diagnosed with advanced testicular cancer. Combination chemotherapy is being considered. Cisplatin is included in the regimen because of its effect on which of the following?

    • A.

      Dihydrofolate reductase

    • B.

      DNA

    • C.

      Microtubules

    • D.

      Purine ring biosynthesis

    • E.

      Ribonucleotide reductase

    Correct Answer
    B. DNA
    Explanation
    Cisplatin crosslinks DNA in several different ways, interfering with cell division by mitosis. The damaged DNA elicits DNA repair mechanisms, which in turn activate apoptosis when repair proves impossible (from Wikipedia)

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  • 6. 

    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?

    • A.

      Acute compression fracture of the L-3 vertebral body

    • B.

      Herniated L-3 to L-4 intervertebral disc

    • C.

      Leaking aortic aneurysm

    • D.

      Perforated rectum

    • E.

      Perforated sigmoid colon

    Correct Answer
    C. Leaking aortic aneurysm
    Explanation
    Based on the given symptoms and findings, the most likely diagnosis is a leaking aortic aneurysm. The patient's presentation of sudden onset weakness, nausea, abdominal and back pain that radiates to the lower extremities, along with pale appearance, cold sweat, weak pulses in the lower extremities, and a faint bruit in the lower abdomen, are consistent with a ruptured or leaking abdominal aortic aneurysm. This is a life-threatening condition that requires immediate medical intervention. Acute compression fracture of the L-3 vertebral body, herniated L-3 to L-4 intervertebral disc, perforated rectum, and perforated sigmoid colon do not explain the full range of symptoms and findings seen in this patient.

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  • 7. 

    QUESTION & IS MISSING FROM THE ORIGINAL FILE

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
  • 8. 

    A 48-year old woman with ductal carcinoma of the right breast has a modified radical mastectomy. After the operation, she has winging of the scapula when she presses her outstretched arms against a wall. Which of the following nerves is most likely injured?

    • A.

      Axillary

    • B.

      Long thoracic

    • C.

      Lower subscapular

    • D.

      Suprascapular

    • E.

      Thoracodorsal

    Correct Answer
    B. Long thoracic
    Explanation
    The long thoracic nerve innervates the serratus anterior muscle, which is responsible for stabilizing the scapula against the thoracic wall. Injury to the long thoracic nerve can result in winging of the scapula, as seen in this patient when she presses her outstretched arms against a wall. The other nerves listed do not innervate the serratus anterior muscle and would not cause this specific symptom.

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  • 9. 

    A 78-year old man comes to the physician because of a 3-month history of increasingly severe back pain. He has had a 5.4-kg (12-lb) weight loss during this period. The pain occurs mostly at night, is exacerbated by movement, and is no longer relieved by aspirin. There has been no trauma to the area. He appears chronically ill. His pulse is 100/min, and blood pressure is 160/100 mm Hg. Physical examination shows point tenderness over L4-5 area; there are no skin lesions. Urinalysis shows 4+ proteins. A photomicrograph of findings from bone marrow aspiration is shown. Which of the following is the most likely diagnosis?

    • A.

      Hyperparathyroidism

    • B.

      Metastatic bone disease

    • C.

      Multiple myeloma

    • D.

      Osteitis deformans (Paget disease)

    • E.

      Waldenstrom macroglobulinemia

    Correct Answer
    C. Multiple myeloma
    Explanation
    The patient's presentation of severe back pain, weight loss, and point tenderness over the L4-5 area, along with the presence of 4+ proteins in the urine, is highly suggestive of multiple myeloma. Multiple myeloma is a malignancy of plasma cells that commonly presents with bone pain, hypercalcemia, renal failure, and anemia. The photomicrograph of findings from bone marrow aspiration would likely show an increase in abnormal plasma cells, confirming the diagnosis. Hyperparathyroidism, metastatic bone disease, Paget disease, and Waldenstrom macroglobulinemia do not typically present with the same constellation of symptoms and findings as seen in this patient.

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  • 10. 

    A 39-year old man comes to the physician because he has had an intense, stabbing pain behind his left eye for 5 nights. The headaches generally begin 1 hour after he goes to bed and last for about 1 hour. During the pain, he has left-sided nasal stuffiness and tearing from his left eye. He had a similar series of nightly headaches for 6 weeks several years ago. Which of the following is the most likely diagnosis?

    • A.

      Cluster headache

    • B.

      Factitious disorder

    • C.

      Generalized anxiety disorder

    • D.

      Sinusitis

    • E.

      Temporal arteritis

    • F.

      Tension-type headache

    Correct Answer
    A. Cluster headache
    Explanation
    Cluster headaches: recurrent brief attacks of sudden severe unilateral peri-orbital pain. Can occur unexpectedly, often at a specific time of day/year, particularly during sleep. Causes excruciating pain behind the eyes. Idiopathic

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  • 11. 

    A 40-year old man is brought to the emergency department after being involved in a motor vehicle collision. He is pronounced dead on arrival. He had a history of fever, headache, chills and pain in the upper right quadrant of the abdomen 5 days ago. 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.

      Apoptosis

    • B.

      Atrophy

    • C.

      Caseous necrosis

    • D.

      Coagulation necrosis

    • E.

      Dysplasia

    • F.

      Fatty change

    • G.

      Heterophagy

    • H.

      Liquefaction necrosis

    • I.

      Metaplasia

    Correct Answer
    A. Apoptosis
    Explanation
    The histologic findings of small shrunken hepatocytes with intense eosinophilic cytoplasm, fragmented nuclear chromatin, and cytoplasmic bleb formations suggest apoptosis. Apoptosis is a programmed cell death that occurs in response to various stimuli, such as infection or injury. It is characterized by cell shrinkage, chromatin condensation, and the formation of apoptotic bodies. In this case, the patient's symptoms of fever, headache, chills, and pain in the upper right quadrant of the abdomen may be indicative of an underlying infection or inflammation, which could trigger apoptosis in the liver cells.

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  • 12. 

    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.

      Celiac sprue

    • B.

      Irritable bowel syndrome

    • C.

      Ischemic colitis

    • D.

      Pancreatic insufficiency

    • E.

      Regional enteritis

    • F.

      Ulcerative colitis

    Correct Answer
    C. Ischemic colitis
    Explanation
    The patient's presentation of bloody diarrhea and diffuse abdominal pain, along with the findings of patchy ulceration on colonoscopy, is consistent with the diagnosis of ischemic colitis. Ischemic colitis occurs when there is a decrease in blood flow to the colon, leading to inflammation and ulceration. This can be caused by various factors, such as atherosclerosis, emboli, or low blood pressure. Given the patient's age and history of cerebral infarction, it is plausible that she may have vascular disease that has affected the blood supply to her colon, resulting in ischemic colitis.

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  • 13. 

    Homologous pairing of chromosomes in prophase I is essential for which of the following normal processes?

    • A.

      Centromere division

    • B.

      Chromosome uncoiling

    • C.

      Crossing over

    • D.

      DNA replication

    Correct Answer
    C. Crossing over
    Explanation
    Homologous pairing of chromosomes in prophase I is essential for crossing over. During crossing over, homologous chromosomes exchange genetic material, resulting in genetic recombination. This process increases genetic diversity and ensures the proper segregation of chromosomes during meiosis. Centromere division, chromosome uncoiling, and DNA replication are not directly dependent on homologous pairing and crossing over.

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  • 14. 

    A 20-year-old man has had hemoptysis, hematuria, and a 10-kg (22-1b) weight loss over the past 3 months. Laboratory studies show a hypochromic microcytic anemia. Which of the following sets of microscopic findings is most likely in tissue obtained on biopsy of his kidney?

    • A.

      A

    • B.

      B

    • C.

      C

    • D.

      D

    Correct Answer
    B. B
  • 15. 

    A 72-year old man is brought to the emergency department because of a 1-week history of increasingly severe abdominal pain, diarrhea, and loss of appetite. He had had a fever for 2 days. His temperature is 38.3C (101F), and pulse is 106/min. Abdominal examination shows distention and rebound tenderness localized to the left lower quadrant. His leukocyte count is 18,000/mm3 (80% segmented neutrophils, 10% bands, and 10% lymphocytes). An abdominal CT scan shows a 7-mm, thickened colonic wall, and pericolic fat inflammation; there is a collection of contrast in this region. Which of the following is the most likely diagnosis?

    • A.

      Amebiasis

    • B.

      Collagenous colitis

    • C.

      Colon cancer

    • D.

      Diverticulitis

    • E.

      Ulcerative colitis

    Correct Answer
    D. Diverticulitis
    Explanation
    The most likely diagnosis in this case is diverticulitis. Diverticulitis is characterized by inflammation and infection of the diverticula, which are small pouches that can form in the colon. The patient's symptoms of abdominal pain, diarrhea, and loss of appetite, along with the physical examination findings of distention and rebound tenderness localized to the left lower quadrant, are consistent with diverticulitis. The presence of a thickened colonic wall and pericolic fat inflammation on the abdominal CT scan further support this diagnosis.

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  • 16. 

    A 26-year old primigravid woman delivers a 2948-g (6-lb 8-oz) male newborn at term. Six months ago, she received a vaccine, Streptococcus agalactiae (group B), serotype III, during a clinical trial. Screening indicated that she had generated an antibody response to this polysaccharide antigen within 1 month of the vaccine. This antibody was detected in her serum immediately prior to the onset of labor. Eight hours after delivery, the newborn appears progressively lethargic, and his temperature is 38.2C (100.8F). Cerebrospinal fluid and blood cultures grow S. agalactiae (group B), serotype III. It is suspected that the mother produced only one antibody isotype in response to the vaccine. This isotype is most likely which of the following?

    • A.

      IgA

    • B.

      IgD

    • C.

      IgE

    • D.

      IgG

    • E.

      IgM

    Correct Answer
    E. IgM
    Explanation
    The correct answer is IgM. IgM is the first antibody isotype produced during an immune response and is involved in the primary immune response. In this case, the mother received a vaccine and generated an antibody response to the polysaccharide antigen within 1 month. The presence of IgM in her serum prior to labor suggests that she produced IgM antibodies in response to the vaccine. IgM antibodies are typically produced early in an immune response and are involved in neutralizing pathogens and activating the complement system.

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  • 17. 

    A 52-year old man comes to the physician because of a 3-month history of epigastric abdominal pain; he also has had an unintentional 6.8-kg (15-lb) weight loss during this period. He has osteoarthritis treated with naproxen as needed. He immigrated to the USA from Japan 6 months ago. He eats mostly traditional Japanese food prepared by his wife. He has smoked 2 packs of cigarettes daily for 30 years and drinks three to four glasses of wine daily. He is 170 cm (5ft 7in) tall and now weighs 82kg (180 lb), BMI is 28 kg/m2. Physical examination shows epigastric tenderness. Upper gastrointestinal endoscopy shows a 4-cm ulcer in the stomach. Examination of a biopsy specimen of the lesion confirms adenocarcinoma. Which of the following is the strongest predisposing risk factor for this patient’s condition?

    • A.

      Alcohol use

    • B.

      Diet

    • C.

      Ethnicity

    • D.

      Naproxen use

    • E.

      Tobacco use

    Correct Answer
    B. Diet
    Explanation
    The strongest predisposing risk factor for this patient's condition is diet. The patient's history of unintentional weight loss and epigastric abdominal pain, along with the finding of a gastric ulcer confirmed to be adenocarcinoma, suggests the presence of gastric cancer. Diet plays a significant role in the development of gastric cancer, and the patient's traditional Japanese diet may be a contributing factor. Certain dietary factors, such as high salt intake, low fruit and vegetable consumption, and the consumption of smoked or pickled foods, have been associated with an increased risk of gastric cancer.

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  • 18. 

    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?

    • A.

      Autoimmune hyperactivation of nicotinic receptors

    • B.

      Autoimmune inactivation of muscarinic receptors

    • C.

      Desensitization of nicotinic receptors

    • D.

      Hypersensitization of muscarinic receptors

    • E.

      Insufficient release of acetylcholine

    Correct Answer
    C. Desensitization of nicotinic receptors
    Explanation
    The most likely cause of the increased muscle weakness in this patient is desensitization of nicotinic receptors. Myasthenia gravis is an autoimmune disorder characterized by the production of antibodies against nicotinic acetylcholine receptors at the neuromuscular junction. Neostigmine, a cholinesterase inhibitor, is commonly used to treat myasthenia gravis by increasing the availability of acetylcholine at the neuromuscular junction. However, long-term use of neostigmine can lead to desensitization of the nicotinic receptors, resulting in decreased responsiveness to acetylcholine and worsening muscle weakness.

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  • 19. 

    A cluster of three cases of nosocomial pneumonia caused by a highly resistant strain of Klebiella pneumonia occurs in a 13-bed intensive care unit (ICU). Each patient in the ICU is in a private, enclosed room. Which of the following infection control measures is most likely to decrease the spread of this organism to the other patients in the ICU and elsewhere in the hospital?

    • A.

      Place infected patients in rooms with at least six air exchanges per hour

    • B.

      Place patients in rooms with negative air pressure

    • C.

      Place infected patients in rooms with positive air pressure

    • D.

      Promote thorough hand cleansing before and after medical personnel visit each patient

    • E.

      Require medical personnel to wear masks when visiting infected patients

    Correct Answer
    D. Promote thorough hand cleansing before and after medical personnel visit each patient
    Explanation
    Promoting thorough hand cleansing before and after medical personnel visit each patient is the most likely infection control measure to decrease the spread of the highly resistant strain of Klebiella pneumonia. Hand hygiene is a crucial aspect of infection control and can effectively prevent the transmission of pathogens. By ensuring that medical personnel properly clean their hands before and after visiting each patient, the risk of spreading the organism to other patients in the ICU and elsewhere in the hospital can be significantly reduced.

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  • 20. 

    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.

      Albendazole

    • B.

      Bithionol

    • C.

      Diethylcarbamazine

    • D.

      Niclosamide

    • E.

      Praziquantel

    Correct Answer
    E. Praziquantel
    Explanation
    Praziquantel is the correct answer because it is known to increase the permeability of cell membranes to calcium, leading to paralysis and death of parasites. This aligns with the results of the experiment described in the question. Albendazole, Bithionol, Diethylcarbamazine, and Niclosamide do not have the same mechanism of action as Drug X and therefore are not the most closely resembling option.

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  • 21. 

    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.

      Axillary nerve

    • B.

      Musculocutaneous nerve

    • C.

      Posterior cord of the brachial plexus

    • D.

      Radial nerve

    • E.

      Thoracodorsal nerve

    Correct Answer
    B. Musculocutaneous nerve
    Explanation
    The Musculocutaneous Nerve (C5-C7) innervates the flexors in the arm- the biceps brachii, brachialis, and Coracobrachialis. It then travels to the lateral forearm where it provides cutaneous innervation.

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  • 22. 

    A 6-year old boy is found to have almond-shaped eyes, temperature instability, mental retardation, hyperphagia, and obesity. Cytogenetic analysis shows a balanced translocation involving chromosome 15q11-q13. His father and paternal aunt are found to have an identical balanced translocation. His aunt’s 5-year old daughter has a history of inappropriate laughter, abnormal gait, and mental retardation. Which of the following genetic principles best explains the findings in this family?

    • A.

      Anticipation

    • B.

      Genetic drift

    • C.

      Heteroplasmy

    • D.

      Imprinting

    • E.

      Pseudodominant inheritance

    Correct Answer
    D. Imprinting
    Explanation
    Imprinting is the best genetic principle that explains the findings in this family. Imprinting refers to the differential expression of a gene depending on whether it is inherited from the mother or the father. In this case, the balanced translocation involving chromosome 15q11-q13 is likely disrupting the expression of imprinted genes in this region. This disruption leads to the clinical features observed in the affected individuals, such as almond-shaped eyes, mental retardation, and hyperphagia. The fact that both the father and paternal aunt have the same balanced translocation suggests that the translocation is inherited in an imprinted manner.

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  • 23. 

    The tracing shows contractile responses of a skeletal muscle preparation to electrical stimulation at five different frequencies. The amount of calcium sequestration in sarcoplasmic reticulurn is highest during which of the fallowing labeled responses?

    • A.

      A

    • B.

      B

    • C.

      C

    • D.

      D

    • E.

      E

    Correct Answer
    E. E
    Explanation
    The correct answer is E. Based on the given information, the amount of calcium sequestration in the sarcoplasmic reticulum is highest during response E. This can be inferred because response E shows the strongest contractile response to electrical stimulation. Since calcium is essential for muscle contraction, the higher the contractile response, the higher the amount of calcium sequestration in the sarcoplasmic reticulum.

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  • 24. 

    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.

      Selenium causes gastric cancer

    • B.

      Selenium exposure is unrelated to gastric cancer

    • C.

      Selenium is associated with a higher risk of gastric cancer

    • D.

      Selenium is associated with a lower risk of gastric cancer

    • E.

      Selenium is positively correlated with gastric cancer

    Correct Answer
    D. Selenium is associated with a lower risk of gastric cancer
    Explanation
    The most appropriate interpretation of the finding is that selenium is associated with a lower risk of gastric cancer. This is supported by the relative risk estimate of 0.3, which is less than 1. A relative risk less than 1 indicates a lower risk of the outcome (gastric cancer) in individuals with a high-selenium diet compared to those without. Additionally, the confidence interval of 0.1-0.8 suggests that the true relative risk falls within this range with 95% certainty. Therefore, it can be concluded that selenium is associated with a lower risk of gastric cancer.

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  • 25. 

    A male newborn delivered at 34 weeks gestation by an uncomplicated spontaneous vaginal delivery develops respiratory distress 30 minutes later. His respirations are 40/min. Physical examination shows cyanosis and lower rib retractions with respiration. Chest x-rays show fine densities with a reticulogranular appearance bilaterally. Which of the following is the most likely cause of these findings?

    • A.

      Erythroblastosis fetalis

    • B.

      Extralobar sequestration

    • C.

      Intracranial hemorrhage

    • D.

      Pulmonary surfactant deficiency

    • E.

      Situs inversus

    Correct Answer
    D. Pulmonary surfactant deficiency
    Explanation
    The presentation of respiratory distress shortly after birth, along with cyanosis, lower rib retractions, and fine densities with a reticulogranular appearance on chest x-rays, suggests a diagnosis of pulmonary surfactant deficiency. Pulmonary surfactant is responsible for reducing surface tension in the alveoli, allowing for proper lung expansion and gas exchange. In premature infants, insufficient production or lack of surfactant can lead to respiratory distress syndrome (RDS). This condition is more common in premature infants, especially those born before 34 weeks gestation. Erythroblastosis fetalis, extralobar sequestration, intracranial hemorrhage, and situs inversus would not typically present with the same respiratory findings.

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  • 26. 

    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.

      Decreased oxygen consumption after phagocytosis

    • B.

      Defective neutrophil degranulation

    • C.

      Defective production of prostaglandins

    • D.

      Inability to produce hydrogen peroxide

    • E.

      Inability to produce hydroxyl-halide radicals

    Correct Answer
    E. Inability to produce hydroxyl-halide radicals
    Explanation
    This patient's recurrent yeast infections and deficiency of myeloperoxidase suggest a defect in the production of hydroxyl-halide radicals. Myeloperoxidase is an enzyme that catalyzes the production of hydroxyl-halide radicals, which are important for the killing of microorganisms by neutrophils. Without the production of these radicals, the patient's neutrophils would have impaired ability to kill microorganisms, leading to increased susceptibility to infections. Decreased oxygen consumption after phagocytosis, defective neutrophil degranulation, defective production of prostaglandins, and inability to produce hydrogen peroxide are not directly related to the production of hydroxyl-halide radicals and are therefore less likely to be the cause of the patient's increased susceptibility to infections.

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  • 27. 

    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.

      Application of heat

    • B.

      Compression sleeve

    • C.

      Diuretic therapy

    • D.

      Exercise therapy

    • E.

      Passive movement

    Correct Answer
    B. Compression sleeve
    Explanation
    After undergoing a radical mastectomy with removal of the axillary lymph nodes, the woman is experiencing painful edema in her left upper extremity. This is likely due to lymphedema, which occurs when lymphatic drainage is impaired. The most effective therapy for decreasing swelling in this patient is the use of a compression sleeve. Compression therapy helps to improve lymphatic flow and reduce fluid accumulation. Applying heat, diuretic therapy, exercise therapy, and passive movement may have some benefits, but they are not as effective as a compression sleeve in managing lymphedema.

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  • 28. 

    A 50-year-old man with a long-standing history of type 2 diabetes mellitus comes to the physician because of several fainting episodes and fatigue during the past month. He appears chronically ill. His temperature is 37°C (98.6°F), pulse is 95/min, respirations are 17/min, and blood pressure is 155/95mmHg. Physical examination shows pallor. Laboratory studies show: Hemoglobin 8 g/dL Hematocrit 24% Mean corpuscular hemoglobin 30 pg/cell Mean corpuscular hemoglobin concentration 33% Hb/cell Mean corpuscular volume 85 um3 Leukocyte count 8000/mm3 Platelet count 200,000/mm3 SERUM Urea nitrogen 60 mg/dL Creatinine 6 mg/dL Total bilirubin 0.9 mg/dL Which of the following is the most appropriate pharmacotherapy for this patient?

    • A.

      Cyclosporine

    • B.

      Deferoxamine

    • C.

      Erythropoietin

    • D.

      Filgrastim

    • E.

      Folic acid

    • F.

      Oprelvekin

    • G.

      Vitamin B12 (cyanocobalamin)

    Correct Answer
    C. Erythropoietin
    Explanation
    This patient presents with symptoms of anemia, including fatigue and pallor, and has laboratory findings consistent with anemia, such as low hemoglobin and hematocrit levels. The most appropriate pharmacotherapy for this patient is erythropoietin, which is a hormone that stimulates the production of red blood cells. Erythropoietin can be used to treat anemia in patients with chronic kidney disease, which is likely the cause of this patient's anemia given his elevated urea nitrogen and creatinine levels.

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  • 29. 

    A 4-year-old girl has had “puffy" eyes for the past 3 days. She has had an upper respiratory tract infection for the past week. A urine dipstick test shows 3+protein. Urinalysis shows no red or white blood cells or casts. Which of the following mechanisms is the most likely cause of this patient’s condition?

    • A.

      Attack by antiglomerular basement membrane antibodies

    • B.

      Damage to the loop of Henle

    • C.

      Damage to the proximal renal tubule

    • D.

      Loss of negative glomerular charge

    • E.

      Presence of a posterior urethral valve

    Correct Answer
    D. Loss of negative glomerular charge
    Explanation
    Loss of negative glomerular charge is the most likely cause of this patient's condition. The presence of puffy eyes and proteinuria (3+protein on urine dipstick test) suggests that there is an issue with the filtration process in the kidneys. The negative charge on the glomerular basement membrane normally repels negatively charged proteins, preventing them from being filtered into the urine. However, in this case, the negative charge is lost, allowing proteins to pass through and be excreted in the urine. This is known as loss of negative glomerular charge and is commonly seen in conditions such as nephrotic syndrome.

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  • 30. 

    30---MISSING FROM ORIGINAL

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
  • 31. 

    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.

      Neurotransmitter-gated Ca++ channels

    • B.

      Neurotransmitter-gated K+ channels

    • C.

      Neurotransmitter-gated Na+ channels

    • D.

      Voltage-gated Ca+ + channels

    • E.

      Voltage-gated K+ channels

    • F.

      Voltage-gated Na+ channels

    Correct Answer
    D. Voltage-gated Ca+ + channels
    Explanation
    The patient's symptoms, including weakness, numbness, and areflexia, along with the electrophysiologic findings of slow conduction velocity in multiple nerves, suggest a peripheral neuropathy. The decreased sensation to vibration and joint position indicates impaired proprioception, which is mediated by the dorsal columns of the spinal cord. Voltage-gated Ca+ + channels are responsible for the entry of calcium ions into the presynaptic terminal, triggering the release of neurotransmitters, including glutamate, which is essential for normal synaptic transmission in the dorsal columns. Impaired function of these channels could lead to the observed symptoms and electrophysiologic findings.

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  • 32. 

    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.

      Blocked randomization

    • B.

      Population-based

    • C.

      Sample of convenience

    • D.

      Self-selection

    • E.

      Sequential

    Correct Answer
    B. Population-based
    Explanation
    The given sampling technique is population-based because the study sample is selected based on census data, which is representative of the national census data for the factors selected. This means that the sample is chosen in a way that accurately reflects the characteristics of the population being studied, in this case, African American men and women in the USA.

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  • 33. 

    A 45-year-old man is brought to the emergency department because of a 6- hour history of severe headache and confusion. He says that it is the worst headache he has ever had. He appears lethargic. His blood pressure is 130/80 mm Hg. Physical examination shows nuchal rigidity. A CT scan of the head without contrast is shown. Which of the following is the most likely cause of this patient's condition?

    • A.

      Diffuse cerebral edema

    • B.

      Hydrocephalus

    • C.

      Large mass hi the posterior fossa

    • D.

      Subarachnoid hemorrhage

    • E.

      Subdural hematoma

    Correct Answer
    D. Subarachnoid hemorrhage
    Explanation
    The patient's presentation of severe headache, confusion, nuchal rigidity, and the worst headache he has ever had is highly suggestive of subarachnoid hemorrhage. Subarachnoid hemorrhage occurs when there is bleeding into the subarachnoid space, often due to rupture of an intracranial aneurysm. The presence of nuchal rigidity indicates meningeal irritation, which is a common finding in subarachnoid hemorrhage. A CT scan without contrast is the initial imaging modality of choice for suspected subarachnoid hemorrhage, and it may show evidence of blood in the subarachnoid space.

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  • 34. 

    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?

    • A.

      Alcohol

    • B.

      Amphetamine

    • C.

      Amyl nitrate

    • D.

      Cannabis

    • E.

      Heroin

    Correct Answer
    B. Amphetamine
    Explanation
    The patient's symptoms of behavioral changes, failing classes, staying out late, increased pulse and blood pressure, pupillary dilation, diaphoresis, agitated affect, and confused thought process are consistent with intoxication with amphetamines. Amphetamines are stimulant drugs that can cause increased energy, euphoria, and hyperactivity. They can also lead to impaired judgment, confusion, and agitation. The patient's exposure to a new neighborhood with drug-addicted and criminal teenagers suggests a potential source of amphetamine use.

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  • 35. 

    A 70-year-old man comes to the physician because of a rash for 7 days. Physical examination shows multiple 4-to s-cm tense bullae filled with clear fluid over the inner aspects of the forearms, lower abdomen, groin, and thighs_ Examination of a skin biopsy specimen shows a non-acantholytic blister with separation of the epidermis from the basement membrane. Serologic studies are most likely to show an autoantibody directed against which of the following?

    • A.

      Anchoring filaments

    • B.

      Collagen, type IV

    • C.

      Desmosomal proteins

    • D.

      Hemidesmosomal proteins

    • E.

      Intracellular adhesion molecule-1

    Correct Answer
    D. Hemidesmosomal proteins
    Explanation
    This is Bullous pemphigoid

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  • 36. 

    A 24-year-old man comes to the physician with his 25-year-old wife because they have been unable to conceive for 3 years_ The wife has been evaluated for infertility, and the test results were normal Analysis of the man's semen shows normal numbers of living sperm but they are immotile. In addition to infertility, this man is most likely to have which of the following associated conditions?

    • A.

      Cholelithiasis

    • B.

      Coronary artery disease

    • C.

      Fat malabsorption

    • D.

      Glomerulonephritis

    • E.

      Sinusitis

    Correct Answer
    E. Sinusitis
    Explanation
    This man is most likely to have sinusitis because the scenario suggests that the man has Kartagener syndrome, a condition characterized by immotile cilia. Kartagener syndrome is associated with primary ciliary dyskinesia, which can lead to chronic respiratory infections such as sinusitis. The other conditions listed are not typically associated with immotile cilia or infertility.

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  • 37. 

    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?

    • A.

      Metastatic colonic adenocaroinoma

    • B.

      Metastatic squarnous cell carcinoma of the larynx

    • C.

      Papillary carcinoma of the thyroid gland

    • D.

      Paraganglioma

    • E.

      Parathyroid adenoma

    Correct Answer
    D. Paraganglioma
    Explanation
    The presence of a 5-cm, rounded mass next to the bifurcation of the carotid artery, positive immunohistochemistry for synaptophysin, chromogranin, and neuron-specific enolase, and numerous electron-dense, membrane-bound neurosecretory granules seen on electron microscopy are all characteristic findings of a paraganglioma. Paragangliomas are neuroendocrine tumors that arise from the paraganglia, which are clusters of neuroendocrine cells located along the autonomic nervous system. They can occur in various locations, including the head and neck, and are often positive for neuroendocrine markers. In this case, the presence of the mass in the neck and the positive immunohistochemistry and electron microscopy findings support the diagnosis of a paraganglioma.

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  • 38. 

    A 25-year old man with cystic fibrosis comes to the physician because of a 3-day history of fever, cough, and progressive shortness of breath. His temperature is 38C (100.4F) and respirations are 32/min. Bilateral crackles and rhonchi are heard on auscultation of the chest. A nutrient agar plate seeded with bronchial secretions grows an aerobic, oxidase-positive, gram-negative rod that forms slimy colonies and produces pyocyanin. The organism does not ferment lactose. Treatment with multiple appropriate antibiotics has not led to eradication of the causal organism. Which of the following is the most likely explanation for the persistent colonization of this patient by organism?

    • A.

      Bacteriophage superinfection

    • B.

      Biofilm formation the lower respiratory tract

    • C.

      Overgrowth of acapsular strains

    • D.

      Pyocyanin synthesis

    • E.

      Synthesis of exotoxin A

    Correct Answer
    B. Biofilm formation the lower respiratory tract
    Explanation
    The most likely explanation for the persistent colonization of this patient by the organism is biofilm formation in the lower respiratory tract. Biofilm is a protective layer formed by bacteria that allows them to adhere to surfaces and resist eradication by antibiotics. In cystic fibrosis patients, the thick mucus in the airways provides an ideal environment for biofilm formation. This biofilm protects the bacteria from antibiotics and the immune system, leading to chronic infections.

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  • 39. 

    A 57-year old man dies of myocardial infarction. At autopsy , examination of the tissue shows alveoli containing epithelial cells that are cuboidal in shape with electron dense lamellar bodies 1-2 u in diameter. These cells most likely produce which of the following?

    • A.

      Collagen, type I

    • B.

      Epinephrine

    • C.

      Histamine

    • D.

      IgG

    • E.

      Surfactant

    Correct Answer
    E. Surfactant
    Explanation
    The presence of cuboidal epithelial cells with electron dense lamellar bodies in the alveoli suggests that these cells are producing surfactant. Surfactant is a substance that reduces surface tension in the alveoli, preventing them from collapsing and facilitating gas exchange. This is important for maintaining proper lung function. The other options, such as collagen, type I, epinephrine, histamine, and IgG, are not associated with the production of surfactant.

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  • 40. 

    A 55-year-old man is brought to the emergency department 45 minutes after he collapsed at home. His pulse is 120/min, respirations are 16/min, and blood pressure is 80/45 mmHg. Physical examination shows no other abnormalities. His hemoglobin concentration is 8g/dL, hematocrit is 24%, and platelet count is 240,000/mm3. Endoscopy shows a bleeding duodenal ulcer, which is surgically repaired. He receives 4 units of packed red blood cells. Two days later, laboratory studies show: Hemoglobin 10 g/dL Hematocrit 30% SERUM Urea nitrogen 70 mg/dL Creatinine 3 mg/dL URINE Blood absent Sediment granular casts Volume 100 m1124 h Total protein 100 mg/24 h Sodium 50 mEq/L Fractional excretion of sodium 2.5% Osmolality 300 mOsmol/kg H20 Two weeks later, the urine sediment is clear and renal function is normal. Histologic examination of a renal biopsy specimen is most likely to show which of the following at this time?

    • A.

      Coagulation necrosis

    • B.

      Collagen scar

    • C.

      Granulation tissue

    • D.

      Lymphocytic infiltrate and fibrogenesis

    • E.

      Regenerating tubular epithelial cells

    Correct Answer
    E. Regenerating tubular epithelial cells
    Explanation
    The patient presented with acute kidney injury (AKI) following a significant blood loss due to a bleeding duodenal ulcer. The laboratory findings, including elevated urea nitrogen and creatinine levels, along with the presence of granular casts in the urine sediment, indicate acute tubular necrosis (ATN) as the cause of AKI. The subsequent improvement in renal function, as indicated by clear urine sediment and normal renal function two weeks later, suggests regeneration of the tubular epithelial cells. Therefore, the histologic examination of a renal biopsy specimen at this time is most likely to show regenerating tubular epithelial cells.

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  • 41. 

    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.

      Greater number of branches supplying the visceral pleura

    • B.

      Larger number of anastomoses with the intercostal arteries

    • C.

      Larger percentage of cardiac output

    • D.

      Larger volume of nutrient blood to the conducting airways

    • E.

      Lower-volume, higher pressure system

    Correct Answer
    C. Larger percentage of cardiac output
    Explanation
    The pulmonary circulation is responsible for oxygenating the blood and removing carbon dioxide, while the bronchial circulation supplies blood to the conducting airways of the lungs. Since the pulmonary circulation is directly involved in gas exchange, it is expected to have a larger percentage of cardiac output compared to the bronchial circulation. This is because a larger amount of blood needs to be oxygenated and circulated to the lungs for gas exchange to occur. Therefore, the correct answer is that the pulmonary circulation has a larger percentage of cardiac output.

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  • 42. 

    An otherwise healthy 23-year old woman comes to the physician because she has not had a menstrual period for 2 months. Menarche occurred at the age of 14 years, and menses had occurred at regular 28-day intervals. Pelvic examination shows blue-tinged vaginal mucosa. The uterus is somewhat soft in the lower segment and is about the size of an orange. The adnexa are nontender with normal-sized ovaries. Which of the following is the most appropriate next step to establish the diagnosis?

    • A.

      Measurement of serum follicle-stimulating hormone concentration

    • B.

      Measurement of serum thyroid-stimulating hormone concentration

    • C.

      Measurement of urine B-human chorlonic gonadotropin concentration

    • D.

      Ultrasonography of the pelvis

    • E.

      Endometrial biopsy

    Correct Answer
    C. Measurement of urine B-human chorlonic gonadotropin concentration
    Explanation
    The patient's presentation of amenorrhea, blue-tinged vaginal mucosa, and soft uterus suggests a diagnosis of Asherman syndrome, which is characterized by intrauterine adhesions that result in menstrual abnormalities. The most appropriate next step to establish the diagnosis is to measure urine B-human chorionic gonadotropin (hCG) concentration. This is because Asherman syndrome can cause a false-negative pregnancy test due to the inability of the endometrium to respond to hCG. Therefore, measuring urine hCG can help rule out pregnancy as a cause of the patient's amenorrhea and further support the diagnosis of Asherman syndrome.

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  • 43. 

    43. MISSING FROM ORIGINAL

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
  • 44. 

    A 16-year old boy has a 6-month history of type 1 diabetes mellitus and requires daily insulin injections. His blood glucose control has been poor recently, which the physician suspects may be related to the patient’s reluctance to self-administer insulin. Which of the following questions is the most appropriate to broach this issue with the patient?

    • A.

      “Giving yourself insulin injections can be difficult. What’s it like for you?”

    • B.

      “I get the feeling you have not been taking your insulin regularly. Would you like me to arrange some training for you by our nurses?”

    • C.

      “It’s been my experience that most poorly controlled diabetics have trouble giving themselves insulin. Do you have this problem?”

    • D.

      “You are clearly having difficulty with insulin injections. Would you like to arrange for a family member to give you your shots?”

    • E.

      “You seem to have missed your shots. How often has this happened?”

    Correct Answer
    A. “Giving yourself insulin injections can be difficult. What’s it like for you?”
    Explanation
    This question is the most appropriate because it allows the patient to express their feelings and experiences with self-administering insulin. It opens up a conversation about any difficulties or challenges the patient may be facing, without making assumptions or placing blame. This approach promotes open communication and understanding between the physician and the patient, which can help identify any barriers to insulin administration and find appropriate solutions.

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  • 45. 

    A 29-month old boy is brought to the physician by his mother because of a 2-week history of green nasal discharge and cough. He has a past history of frequent respiratory tract illnesses and pneumonia. The mother states that her son has a 6-month history of large, foul smelling stools and a salty taste when she kisses him. There is no family history of a similar condition. He is at the 5th percentile for height and below the 3rd percentile for weight. His temperature is 38.3C (100.9F). Abdominal examination shows distention. Genetic testing shows a mutation in the Phe residue at position 508 in the cystic fibrosis transmembrane conductance regulator gene. Which of the following types of modification is required prior to destruction of misfolded proteins in this patient’s proteasomes?

    • A.

      Dimerization

    • B.

      Glycosylation

    • C.

      Phosphorylation

    • D.

      Sulfation

    • E.

      Ubiquitination

    Correct Answer
    E. Ubiquitination
    Explanation
    The correct answer is ubiquitination. Ubiquitination is a post-translational modification process in which ubiquitin molecules are attached to proteins. This modification targets the proteins for degradation by the proteasome. In this patient with cystic fibrosis, there is a mutation in the cystic fibrosis transmembrane conductance regulator gene, leading to misfolded proteins. These misfolded proteins need to be destroyed, and this is achieved through ubiquitination followed by proteasomal degradation. Dimerization, glycosylation, phosphorylation, and sulfation are not directly involved in the degradation of misfolded proteins.

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  • 46. 

    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.

      Estradiol

    • B.

      Estrone

    • C.

      Follicle-stimulating hormone

    • D.

      Human chorionic gonadotropin

    • E.

      Luteinizing hormone

    • F.

      Testosterone

    Correct Answer
    F. Testosterone
    Explanation
    The patient's history of alcohol consumption and physical examination findings suggest that he has liver cirrhosis. Liver cirrhosis can lead to a decrease in testosterone production, which can cause erectile dysfunction. Testosterone is the primary male sex hormone responsible for maintaining sexual function. Therefore, decreased serum concentrations of testosterone are the most likely cause of this patient's erectile dysfunction.

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  • 47. 

    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.

      Decreased glycogen synthesis

    • B.

      Decreased myosin light chain phosphatase activity

    • C.

      Increased phosphatidyl degradation

    • D.

      Increased protein degradation

    • E.

      Mitochondria damage

    • F.

      Necrosis of muscle fibers

    Correct Answer
    D. Increased protein degradation
    Explanation
    The most likely cause of the decrease in calf circumference is increased protein degradation. This is because the patient had a ruptured Achilles tendon which required surgical repair and immobilization. Immobilization can lead to muscle atrophy and loss of muscle mass. Increased protein degradation is a key mechanism in muscle wasting and atrophy. Therefore, it is the most likely cause of the decrease in calf circumference.

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  • 48. 

    48. MISSING FROM ORIGINAL

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
  • 49. 

    A previously healthy 42-year old Asian woman is brought to the emergency department because of a 24-hour history of nausea, vomiting and progressive lethargy. She has smoked 1 pack of cigarettes daily for 25 years and drinks four glasses of wine daily. She uses high-dose acetaminophen daily for headaches. She does not use illicit drugs. She is 155 cm (5ft 1 in) tall and weighs 50 kg (110 lb); BMI is 21 kg/m2. She is responsive to painful stimuli. Initial laboratory studies show increased hepatic aminotransferase. Which of the following effects of alcohol most likely contributed to this patient’s condition?

    • A.

      Decreased generation of N-acetyl-p-benzoquinonelmine

    • B.

      Increased glucuronidation

    • C.

      Increased hepatic glutathione stores

    • D.

      Increased sulfation

    • E.

      Induction of cytochrome P450

    Correct Answer
    E. Induction of cytochrome P450
    Explanation
    The correct answer is "Induction of cytochrome P450." Alcohol is known to induce cytochrome P450 enzymes in the liver, leading to increased metabolism of drugs and toxins. This can result in increased production of toxic metabolites, such as N-acetyl-p-benzoquinonelmine, which can cause liver damage. In this case, the patient's symptoms of nausea, vomiting, and lethargy, along with the increased hepatic aminotransferase levels, are consistent with alcohol-induced liver injury.

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  • 50. 

    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.

      Bromocriptine

    • B.

      Clomiphene

    • C.

      Diethylstilbestrol

    • D.

      Ethinyl estradiol

    • E.

      Medroxyprogesterone

    Correct Answer
    B. Clomiphene
    Explanation
    Clomiphene is a SERM that an Estrogen receptor antagonist in the hypothalamus, which stops negative feedback, and increases GnRH => increase LH, FSH => jumpstarting ovulation

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