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NBME 13 – Flashcard

question

Researcher in pharmaceutical company designs new protease inhibitor that inhibits replication of HIV in T lymphocytes in culture – which of following findings is most likely to indicate that compound is working specifically as protease inhibitor?
answer

Lack of a mature core. – “-navir”; assembly of visions depends on HIV protease (pol gene) which cleaves polypeptide products of HIV mRNA into function parts; protease inhibitors prevent maturation of new viruses. 199
question

20 YO man comes to physician because of cramping abdominal pain and diarrhea during past 3 weeks; he has had a 10 lb weight loss during this period; pain is exacerbated following meals; went on camping trip in upstate NY 3 weeks ago, swimming in nearby lakes and hiking in mountains; vital signs are normal; which of following diagnostic tests identifies casual organism of patient’s condition?
answer

microscopic examination of stool for ova and parasites
question

a previously healthy 54 year old man comes to clinic because of light headedness for 6 hours; symptoms began after skiing at resort of 9000 ft; he has been taking carbonic anhydrase inhibitor since 2 days before arrival at resort; his bp is 110/60 mg Hg while sitting and 95/50 mm Hg while standing; which of the following is the most likely cause of his orthostatic hypotension?
answer

hypovolemia
question

22 yo woman comes to physician 3 months after she notes a painless, slowly enlarging mass on left side of her neck; physical examination shows a freely mobile, soft, cystic mass with cutaneous surface opening; physician explains that it is from incomplete fusion during embryonic development. which of following is most likely location of opening of duct leading to mass in this patient?
answer

anterior to the sternocleidomastoid muscle; branchial cleft cyst
question

What is most effective in decreasing patient’s risk for type II DM? (BMI – 30)
answer

low calorie
question

15 year old boy brought to physician because of painless swelling in left breast for 1 month; no family history of breast cancer. he is at 65th percentile for height and 70th percentile for weight; pulse is 65/min and bop is 118/76; mild facial acne, mustache hair, axillary hair; no adenopathy; left breast is mildly enlarged with palpable breast bud; right breast is normal with no gynecomastia; genitalia are tanner stage 3 – what’s most appropriate initial statement?
answer

this is a common condition for teenage boys and should resolve in time (unilateral; physiologic gynecomastia in teenagers)
question

a 60 year old man comes to the physician because of progressive weakness of his hands during the past 6 months. he works as a carpenter and has had difficulty handling his tools. he has smoked 1 pack of cigarettes daily for 45 years. he drinks 2 beers daily during the work week and 6 beers daily on weekends. physical examination shows no lymphadenopathy. there is decreased strength in upper and lower extremities and atrophy of muscles. he has diffuse hyperreflexia; fasciculations are noticed on muscles of hands and upper extremities. sensory examination is normal. over the course of this disease, which of the following findings is most likely?
answer

difficulty swallowing; ALS; UMN and LMN symptoms (fasciculations = LMN; hyperreflexia = UMN). presents with asymmetric limb weakness, fasciculations and atrophy; fatal; tx: riluzole
question

a 60 yo man has episodes of fluctuating weakness for the past 2 years; the weakness was 1st noticed when he had difficulty lifting books. at times, he has had drooping of the eyelids and double vision. recently, he has had difficulty climbing stairs and regurgitation of liquids into his nose. on physical examination – weakness increases with repeat exercise; x-ray shows mass in mediastinum. which of the following laboratory assays is most likely to be positive?
answer

acetylcholine receptor antibody; myasthenia gravis (associated with thymoma FFS)
question

which of the follows best describes T4 binding substance in blood and type of cellular receptor for T4 in peripheral tissues?
answer

globulin + nuclear receptor
question

44 yo man + 1 year history of angina pectoris comes to ER + increasingly severe chest pain during past 2 days + cardiac examinations hows S4 + ECG shows ST segment depression in precordial leads; given dose of MAB against platelet IIB/IIIA receptor; this antibody will prevent binding of which of the following substances to platelets?
answer

fibrinogen
question

18 yo man + high fever + sore throat + cervical lymph node enlargement for 8 days. latex agglutination test result for EBV antibody is positive. atypical cells with abundant lacey cytoplasm in peripheral blood smear are most likely derived from which of the following types of cells?
answer

T lymphocytes (161)
question

a screening test is used to detect prostate cancer in a population of 100,000 men. the test has a sensitivity of 70% and a specificity of 90%. the test is then used to screen a second population in which the prevalence of prostate cancer is different. which of the following is the most likely effect on the PPV of this test?
answer

increases as prevalence increase.
question

18 month old boy is brought to physician because of progressive facial abnormalities + slow growth during past 6 months. older brother with similar abnormalities who also has mental retardation. physical examination shows coarse facial features, hepatosplenomegaly + joint stiffness. his urine concentrations of derma tan sulfate and heparin sulfate are increased. deficiency of which of the following enzyme activities is most likely cause of findings in patient?
answer

idurinate sulfatase; hunter syndrome (mild hurler + aggressive behavior + no corneal clouding) (84)
question

a 43 year old woman with metastatic colon cancer has maintained remission by taking bevacizumab as a single agent. the ability to administer this agent despite it being a foreign antigen is a result of?
answer

the agent being a humanized antibody
question

a 32 year old woman comes to the physician because of a 1 month history of progressive shortness of breath and anxiety. she says that her symptoms become much more pronounced as the day progresses. BMI is 24. breath sounds are normal on auscultation of chest but patient has difficulty taking a long, deep breath. ABG shows pH of 7.33, pCO2 of 20, pO2 of 65 mm Hg; PFT shows decreased vital capacity, tidal volume, and expiratory reserve volume. residual volume is within normal range. which of the following is most underlying cause of patient’s condition?
answer

myasthenia gravis. worse as day progresses.
question

A 12 year old african american girl is brought to the emergency department by her mother because of a 6 hour history of fever and severe RIB PAIN. She has had numerous episodes in the past. Her paternal aunt and uncle have had similar symptoms since youth. Her temperaaaaaaature is 39. The lungs are clear to auscultation. Abdominal examination shows tenderness to palpation. A peripheral blood smear is shown in the photomicrograph. Which of the following is the most likely underlying cause of this patient’s symptoms?
answer

Polymerization of hemoglobin with hypoxic conditions due to amino acid substitution in the beta chain (400)
question

A 23-year-old man comes to the physician because of a low-grade fever, nasal congestion, and muscle aches for 1 week. He states that his girlfriend recently told him that his eyes appeared yellow. He has not had clay-colored stools or dark urine. His only medication is ibuprofen. He has no recent history of foreign travel tattoos, use of intravenous drugs, or exposure to blood products. He is 183 cm (68) tall and weighs 77 kg (170 lb); BMI is 23 kg/m2. Physical examination shows mild scleral icterus but no subungual icteris. The remainder of the examination shows no abnormalities. Serum studies show: Which of the following is the most likely diagnosis?
answer

gilbert syndrome; high unconjugated (indirect) bilirubin 376
question

A 5-year-old girl is brought to the physician because of listlessness, fatigue, and dull pain in the right upper quadrant of the abdomen. Her height and weight are below the 25th percentile. Laboratory findings indicate that the content of her β-globin chain is 15% to 20% of normal. Sequencing of the β-globin gene shows a point mutation in a sequence 3′ to the coding region in which AATAAA is converted to AACAAA. Consequently, the amount of mRNA for β-globin is decreased to 10% of normal. Which of the following functions in mRNA synthesis and processing is most likely encoded by the sequence AATAAA?
answer

cleavage and polyadenylation. (38)
question

A 25 year old woman comes to the physician because of a 2-day history of dec urine output despite ample fluid intake. she underwent operative removal of a perforated appendix 3 weeks ago. she received intravenous gentamicin for 2 wks. physical examination shows no abnormalities. lab studies show. Serum: urea nitroge: 35mg/dl creatinine: 2.9md/dl urine: specific gravity 1.010 protein 2+ Na+ 25mEq/L casts brown granula Histologic examination of this pts kidneys would most likely show necrotic cells in which of the following components of the nephron?
answer

proximal tubule; ATN (572)
question

A 62-year-old man is brought to the emergency department because of a 3-hour history of progressive difficulty breathing and mild left shoulder pain. His symptoms began after he ran up several flights of stairs. He has poorly controlled hypertension and mild angina pectoris. He has smoked one-half pack of cigarettes daily for 40 years. He appears uncomortable and has labored breathing. Diffuse crackles, ronchi, and scattered wheezing on auscultation of the posterior lung fields. His arterial PO2 is 58 mm Hg. Which of the following is the most likely diagnosis?
answer

Pulmonary edema
question

2. A 64 year old woman comes to the physician because of a 6 month history of heartburn and difficutly swallowing solid and liquid. She has not had nausea or vommitting. She also has a 2 year history of pain and swelling of her wrists and hands. She has not seen a physician in 5 years. She does not smoke. She takes no medications. PE shows no wrinkles on the face and neck. He vitals are within normal limits. There is synovial thickening of the wrists bilaterally. A photograpsh of the left hand is shown. Abdominal exam shows no abnormalities. Which of the following sets of findings is most likely on the esophageal manometry?
answer

esophageal peristalsis = decreased, LES tone = decreased
question

4. A 35 yr old man comes to the physician for a routine exam. He has a 5 yr hx of recurrent episodes of genital herpes treated with acyclovir. He says, “I’ve been taking the medication, but I still occasionally get lesions. When will I be cured?” The phsyiain informs him that herpes simplex is a lifelong infection, with no cure at the present time. Which of the following best explains the longevity of the herpes simplex virus?
answer

establishment of a latent infection in sensory nerve cells
question

An 18-year-old woman with mild mental retardation is brought to the physician because of a 3-day history of decreased ability to see in reduced light. She has a lifelong history of chronic diarrhea. Two years ago, she developed a lack of muscle control of her arms and legs, and generalized weakness. Her 16-year-old brother has had similar symptoms. Ophthalmologic examination shows bilateral retinitis pigmentosa. There is ataxia and loss of deep tendon reflexes. Laboratory studies show erythrocytes with spiny projections and a serum total cholesterol concentration of 40 mg/dL. Which of the following apolipoproteins is most likely deficient in this patient?
answer

ApoB (abetalipoproteinemia) (89)
question

previously healthy 32 yr old man is brought to emergency department because of 1 day history of intermittent flashing spots and blurred vision,vomitting,confusion and difficulty walking. he is a painter and says that yesturday he cleaned up spilled bottle of paint thinner. opthalmologic examination shows dilated pupils with hperemia of the optic disc and retinal edema.physical exam shows tachypnea.serum studies show an anion gap metabolic acidosis. the most appropriate pharmacotherapy for this pathient is most likely to inhibit activity of which of the following?
answer

alcohol dehydrogenase; fomepizole (68)
question

elderly woman with pleural effusion dullness at 7 th rib and below …thoracentesis to be done …best site for insertion of the catheter…
answer

above 9th rib in mid scapular line
question

76 yo woman has stroke, ophthalmologic examination shows hemianopia + tendency to gaze to the right; pupils are normal sized and reactive to light; neurologic examination shows left sided numbness and paralysis that are more severe in face and upper extremity than in lower extremity. which of the following arteries is most likely involved in patient’s condition?
answer

MCA: contralateral face and arm greater than leg weakness, some visual field cut and sensory.aphasia- left brainBrocas- inferior frontal, Wernicke-superior temporal gyrus; right brain NEGLECT parietal
question

A male newborn was delivered at 38 weeks gestation following an uncomplicated pregancy. 12 hours later, he begins sucking frantically and crying inconsolably. He overreacts to stimuli around him and has a marked startle response. Symptoms slowly resolve over the next 2-3 weeks. The most likely explanation for these symptoms is maternal use of which of the following substances during pregnancy?
answer

heroin
question

6. A healthy 21-year-old man dies suddenly of cardiac arrest after snorting cocaine. Cocaine-induced inhibition or which of the following is the most likely explanation for the cardiac arrest?
answer

NE reuptake (231)
question

A 22 y/o woman comes to the physician for a follow-up examination. One year ago, she was diagnosed with a pulmonary embolism. Two years ago, she delivered a female stillborn at 23 weeks’ gestation. Physical examination today shows no abnormalities. Lab studies show a normal platelet count, normal prothrombin time, and increased partial thromboplastin time. The findings in this patient are most consistent with which of the following conditions?
answer

antiphospholipid syndrome (443)
question

A 22-year-old woman is admitted to the hospital because of a 10-day history of polydipsia and polyuria. She says that the urge to urinate often awakens her at night. She has been taking lithium carbonate for 2 years for bipolar disorder; her dosage was increased 6 months ago because of recurrent severe manic episodes. Her vital signs are within normal limits. Physical examination shows no abnormalities. Over the next 24 hours, urine excretion totals 6.5 L. Laboratory studies at this time show a serum sodium concentration of 148 mEq/L, serum osmolality of 315 mOsmol/kg, and urine osmolality of 75 mOsmol/kg. After administration of desmopressin, urine output and osmolality do not change. Which of the following findings in the nephron best describes the tubular osmolality, compared with serum, in this patient? Proximal Tubule — Juxtaglomerular Apparatus — Medullary Collecting Duct A) Hypertonic — hypertonic — hypertonic B) Hypertonic — hypertonic — hypotonic C) Hypertonic — hypotonic — hypotonic D) Isotonic — isotonic — isotonic E) Isotonic — hypotonic — hypertonic F) Isotonic — hypotonic — hypotonic G) Hypotonic — hypertonic — hypertonic H) Hypotonic — hypotonic — hypertonic I) Hypotonic — hypotonic — hypotonic
answer

F
question

Why hypotonic – hypotonic – hypotonic
answer

nephrogenic DI. The question is asking you what the values are in the absence of ADH action. You know the fluid is hypotonic in the medullary collecting duct since the kidneys are not responding to ADH and you’re not absorbing any water. That gets you down to B, C, F. Now you also know the fluid in the proximal tubule is isotonic since ADH doesn’t act on this, and the fluid in the PT is normally isotonic. So the correct answer is F.
question

A 54 yo woman with a 5 day history of severe mid-back pain. Exam shows point tenderness over T6 vertebrae. Serum calcium is 13.4 mg/dL, urinalysis shows Bence Jones proteins. What is the most likely cause of her hypercalcemia?
answer

local IL-1 and tumor necrosis factor effect; multiple myeloma (409)
question

A 2month old boy dies of meningitis despite appropeiate antibiotic therapy.culture of his csf grows myco.tb. two of his brothers died of atypical mycobacterial infections.which of the following immunodeficiencesmost likely explains the family history
answer

IFN-y receptor deficiency
question

A 76 year old man is admitted to the hospital because of a 2 week history of a persistent urinary tract infection. he is 165 cm(5ft 5in) and weighs 55kg(121 lb); BMI is 20 kg/m2). the physician plans to initiate treatment. A component of the initial treatment includes an intravenous bolus dose of an antibiotic to attain an intial peak serum conc. of 8mg/L. the vol of distribution of the antibiotic is 0.35L/kg. lab studies show a 24-hr urine creatinine clearance withing the reference range. which of the following is the most appropriate loading dose of this drug for this patient(in mg)?
answer

this is LD = CP X Vd/F here the cp is the desired peak concentration of drug which is 8 mg and vd is (0.35) and its given per kg so the weight is 55 f bioavailability which is 1 for IV LD= (8)(0.35)(55)/1=154 —> 150 mg is the ans
question

a 9 yo girl is brought to the ED with pain on movement of the right shoulder and a tender clavicle. an xray of the shoulder shows a non displaced fracture of the right clavicle. which of the following structures of the clavicle will most likely assist in producing new bone to heal this fracture?
answer

Periosteum contains progenitor cells that develop into osteoblasts; cells responsible for laying down new bone. (434)
question

A 23 year old woman comes to the physician because of t day hx of chills, nausea, and vomiting. She also has a 4 day history of flank pain, urinary frequency, and pain with urination. Her temp is 102 F pulse is 125/min, and BP 90/60. Physical examination shows right costovertebral angle tenderness. UA shows 25 WBC/hpf. A urine sample grows pink colonies on lactose-MAcConkey agar, produces a characteristic green sheen on eosin-methylene blue agar and is indole +. The production of which of the following by the bacterium aids in the virulence of the causal organism in this patient?
answer

E. Coli – pilus – adhesins*
question

A 49 yo man with pancreatic CA undergoes a whipple. During the procedure the cut end of stomach is joined to the jejunum. Which of the following nerve structures can be cut to decrease stomach acid output and decrease the likelihood of ulcers forming in the jejunum at the site of junction with the stomach?
answer

vagal trunks
question

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

Lymph node involvement
question

A 5-month old boy is brought to the physician because of a 5-day hx of difficulty feeding. PE shows macroglossia and enlargement of the anterior neck at the midline. A CT shows a 4-cm, well-defined, cystic structure in the neck. A remnent of which of the following is the most likely cause?
answer

Thyroglossal Duct
question

An investigator is studying beta2-receptors in female experimental animals. Epinephrine is injected intramuscularly into the animals, and the effects on beta2-adrenoreceptors are then observed. Which of the following physiologic effects is most likely to be observed in these animals? A) Increased myocardial contractility B) Internal urethral sphincter contraction C) Lipolysis (WRONG) D) Pilomotor contraction E) Pupillary dilation F) Uterine relaxation (RIGHT?
answer

Uterine relaxation (234)
question

A 60 yd old man comes to physician becasue of a 2 yr history of progressive shotness of breath with exertion. His two younger sibling have had similar symptoms. His mother died of dilated cardiomyopathy. Physician exam show jugular venous distention and ankle edema. There is hepatomegaly. Inspiratory crackles are heard over both lung bases. A chest x-ray shows cardiomegaly and pulmonary congestion; angiography confirms dilated cardiomyopathy. An atrial endocardial biopsy specimen shows abnormal sarcomeres ith paracrystalline inclusions in mitochondria. Sequencing of mitochondrial DNA shows a G-to-A transition. This results in an added A:T base pair to the 3 inch end of the tRNA, thus shortening the C loop. Which of the following is the most likely effect of this mutation of mitochondrial function?
answer

decreased protein synthesis (40)
question

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

Iron deficiency anaemia + oesophageal webs + glossitis/stomatitis = Plummer-Vinson syndrome (360)
question

An epidemiologist is investigating an outbreak of diarrhea among a total of 1000 consumers of vegetables. Of those consumers, 800 people ate tomatoes and 200 people ate lettuce.A total of 400 people became ill,80 of these people ate tomatoes, and 40 people ate lettuce. Which of the following indicates the probability of having developed diarrhea in people who consumed lettuce?
answer

Take the number of people who became ill eating lettuce (40) / the total number of people who ate lettuce (200) 40/200 = 0.2
question

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 male cousin has similar symptoms. Physical examination shows spasticity, chorea, and mutilation of the digits. Laboratory studies are most likely to show which of the following abnormalities?
answer

hyperuricemia
question

3. A 46 year old man receives diagnosis of SCC of the esophagus. A barium swallow is shown Esophagectomy at the region (there was an accompanying image) is most likely to involve ligation of arterial branches of which of the following vessels?
answer

Esophageal arteries are branches of the aorta
question

An experimental model of treatment for sickle cell disease involves reactivating the genes that code for the b chains of fetal hemoglobin. This treatment is most likely to increase the affinity of hemoglobin for which of the following?
answer

Oxygen (631)
question

An autopsy is done on a 50 year old man who died of pneumonia despite 5 days of abx in the icu. 15 year h/o EtOH abuse. Saggital section of cerebellum is shown. Based on this pathology which of the following findings was most likely present on neurological examination?
answer

gait ataxia, ipsilateral (481)
question

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

Nitric oxide; nitrites (632)
question

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

pulmonary surfactant deficiency
question

31 yo woman comes to the ER with difficult breathing and muscle weakness for 10 minutes. She has a 3 year history of myasthenia gravis treated with neostigmine. The husband reports that she double her doses 2 days ago but her weakness increase since then. Which of the following event is most likely responsible for the increase of the weakness of this patient?
answer

desensitization of nicotinic receptors; myasthenia gravis (445)
question

15 yr old boy brought due to behavioral changes. Hes failing school. Pulse 110, rr 24/min, bp: 140/85. Pupillary dilation and diaphoresis. His affect is agitated and his thought process is confused. What is he intoxicated with?
answer

amphetamine
question

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 155/95 mm Hg. Physical examination shows pallor. Laboratory studies show: Hb: 8 g/dL Htc: 24% MCH: 30 pg/cell MCHC: 33% Hb/cell MCV: 85 pm3 Leukocytes: 8000/mm3 Platelets: 200,000/mm3 Serum Urea Nitrogen 60 mg/dL Serum Creatinine: 6 mg/dL Serum Total Bilirubin 0.9 mg/dL Which of the following is the most appropriate pharmacotherapy for this patient
answer

EPO
question

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 not use illicit drugs. She is 155cm (5ft 1 in) tall and weighs 50 kg (110 lb); BMI is 21 kg/m2. She is responsive to painful stimuli. Initial lab studies show increased hepatic aminotransferase. Which of the following effects of alcohol most likely contributed to this patient’s condition?
answer

E) induction of cytochrome p450; acetaminophen undergoes mainly glucuronidation and sulfation in the liver and also via P450 is converted to N-acetyl-p-benzoquinoneimine(toxic metabolite).So in chronic alcoholic states, there is induction of cytochrome P450 and more conversion of acetaminophen to the above toxic compound with the resultant liver injury.
question

Q.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 gastic cnacer 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?
answer

Glutathione peroxidase uses Glutathione, and Selenium as a cofactor to convert peroxides into water, thus reducing oxidative damage to the colon.
question

a 70 year old man comes to the physiscian becuase of rash for 7 days. physical examination shows multiple 4 to 6 cm tense bullae filled with clear fluid over the inner aspect of the forearms, lower abdomen, groin and thighs. examination of a skin bopsy specimen shows nonacantholytic 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
answer

hemidesmosomes
question

A 9 yr old boy is brought the Emergency dept because of fever chest pain, and migratory join pain of his shoulders, hips, and knees for 2 days. Four weeks ago, he had a febrile pharyngitis, which resolved 2 wks later without treatment. His temp is 102.2 F. The lungs are clear to ausc. A pericardial friction rub and quiet heart sounds are heard. Throat cultures do not grow any pathogens. Lab testing shows increased anitbody titers to streptolysin O. The greastest risk for death at this time is which of the following/
answer

Rheumatic fever can cause myocarditis and this can happen with pericarditis. Keys to this are the pericardial friction rub and quiet heart sounds (pericarditis)
question

2. 10 yr old boy with type 1 diabetes is receiving insulin. One hour after his morning dose he becomes tremulous and diaphoretic and has tachycardia. Several hours later his symptoms resolve. What is the cause of the patients hyperglycemia?
answer

activation of hepatic adenylyl cyclase
question

A 10 year old boy who has type one DM for one year is taking insulin.One hour after his morning dose of insulin he becomes tremulous and diaphoretic and has tachycardia. Seceral hours later his symptoms resolve.his blood glucose concentration is now increased. which of the following is the most likely cause of his 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.
answer

activation of hepatic adenylyl cyclase (81)
question

Tracings of skeletal muscle responses to electrical stimulation and asked which one represented the highest amt of calcium sequestered in the SR
answer

first one is when you have the most calcium in the SR. When you get to the later ones with just a huge continuous contractile spike (tetanus), less calcium is in the SR and more calcium is in the cytosol (low stimulus frequency)
question

Autopsy on a 46 yo woman who died of adenocarcinoma of the colon. Exam of neck shows 5 cm roundd mass next to bifurcation of carotid artery. Immunohistochemistry is positive for synaptophysin, chromogranin and neuron-specific enolase. EM show numerous electron dense, membrane bound neurosecretory granules. Exam of adrenal glands shows no masses. Most likely diagnosis?
answer

paraganglioma
question

An investigator studying the molecular events in the underlying causes of an autoimmune disease develops a collection of monoclonal antibodies to ribosomal proteins. One of the monoclonal antibodies is found to inhibit the ribosome peptidyl transferase. Which of the following is most likely affected in the presence of this antibody?
answer

Establishment of covalent bonding between amino acids
question

otherwise healthy 23 y/o female w/no menstrual period for 2 months. Regular 28 day cycle up to now. Pelvic exam shows blue-tinged vaginal mucosa. Uterus is somewhat soft in lower segment & about the size of an organge. Adnexa nontender; normal sized-ovaries. What is the most appropriate next step in diagnosis?
answer

measure urine b-HCG
question

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 vaccination. 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 38.2°C (100.8°F). 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
answer

IgM; doesn’t cross placenta
question

x myeloperoxidase – which of the following is the most likely cause of increased susceptibility to infections in this patient?
answer

inability to produce hydroxy-halide radicals (105)
question

a 6 year old boy is found to have almond shaped eyes, temperature instability, mental retardation, hyperphagia, and obesity; balanced translocation involving chromosome 15; cousin has history of inappropriate laughter, abnormal gait and mental retardation….what genetic principle best explains findings in this family?
answer

imprinting
question

A cluster of three cases of nosocomial pneumonia caused by a highly resistant strain of Klebsiella pneumoniae 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 other patients in the ICU and elsewhere in the hospital?
answer

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

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?
answer

Larger percentage of CO