NBME Step 1 (Answered) Verified Solution

NBME Step 1 (Answered) Verified Solution Formation of hypnozoites -Pt has malaria → one of the features is that it forms hypnozoites and has the PBS shown Chloroquine resistance -Can happen but it is not a feature A 30M, who is a migrant farm worker presents to the ED b/c of a 1-wk Hx of fever, chills, & severe headache. He immigrated to the midwestern USA from Honduras 1 year ago. He is alert. Temp is 104F, pulse is 101/min, RR are 20/min, BP is 105/62. The lungs are clear to auscultation. Cardiac exam is normal. The abd is soft w/active bowel sounds. Neuro exam shows a supple neck; there is nu nuchal rigidity. He is oriented to person, place, & time. Labs show: -Hb---------------14 -Hct---------------42% -Leuko's----------4,6K -Neutro's----------57% -Lymph's-----------33% -Monocytes-------10% Urine -Color------clear yellow -Blood-------------1+ -Urobilinogen-----trace A pictomicrograph of a PBS is shown. This pt's overall condition is most likely caused by an infectious agent w/which of the following features? (Formation of hypnozoites OR Chloroquine resistance) Conjugation -Allows for transfer of DNA high frequency transfer via: 1-direct cell-to-cell contact 2-via a bridge-like connection pilus between two cells -Classically E.coli allows antibiotic resistance transfer to another species Transduction -Transfer of genetic material via a bacterial phage → Lytic page infects a bacterium, leading to cleavage of bacterial DNA → Parts of bacterial chromosomal DNA then b/c packaged in capsid → phage infects another bacteria In a study of antibiotic resistance, a strain of E.coli resistant to ampicillin but sensitive to streptomycin is cultured w/a strain of salmonella enteritidis sensitive to ampicillin but resistant to streptomycin. After 4 hrs of co-cultivation. the broth is plated onto a solid medium containing both ampicillin & streptomycin. S.enteritidis bacteria that are resistant to both antibiotics grow at a frequency rate of 1 per 100 cells. Which of the following is the most likely mechanism of the acquisition of ampicillin resistance by S.enteritidis? (Conjugation OR Transduction) 20 -Vd is calculated two ways 1-t1/2 = (0.7xVd)/CL OR VD=(C-initial)/Plasma conc We use the second eq so VD = 80mg/(4ug/mL) -but we must convert 4ug to mg so Vd = 80mg/(.004mg/mL) = 20,000mL -then convert to Liters 20,000mL/(1L/1000mL) = 20L An 80M is admitted to the hospital b/c of a 2 wks Hx of severe, persistent UTI. An 80-mg dose of Drug X is administered IV. Thirty mins after the infusion is complete, his serum conc of Drug X is 4ug/mL. Assuming a distribution t1/2 life of 3 mins & an elimination t1/2 of 24 hrs, the volume of distribution of this drug (in L) in the peripheral compartment is closest to which of the following? (2 OR 20) Negative strand RNA Also:PaRaMMyxovirus 1-Mumps & Measles 2-Parainfluenza 3-RSV Is Rubeola (measles) virus a (Negative strand RNA OR Postive strand RNA) Regular exercise -Prevents disease in healthy people → other primary preventions are: 1-Legislation to ban use of hazardous products (asbestos) or to mandate safe practices (seat belts, helmets) 2-Education about health & safe habits (eating well, exercise, not smoking) 3-Immunization Annual mammography -This is used to detect breast cancer only detects after it has already occurred → so secondary prevention → other examples include 1-Daily, low-dose aspirin OR diet and exercise programs after a stroke to prevent future strokes) 2-Modified work so injured of ill workers can return safely to job Tertiary 1-Cardiac or stroke rehab programs, chronic disease mgmt programs (DM, arthritis, depression) 2-Support groups 3-Vocational rehab programs to retrain workers A public health consultant is contacted by a HMO for recommendations about a primary health prevention techniques for a population of women ages 30-40 years. Which of the following is most appropriate primary preventative recommendation for this group? (Regular exercise OR Annual mammography) TGF-β -Wound healing -Stimulates angiogenesis & fibrosis (fibroblast migration & proliferation) - resolution of the inflammatory response TNF-α -Causes cachexia in malignancy -Maintains granulomas -Activates endothelium, causes WBC recruitment, vascular leak A pt presents w/a subcutaneous nodule. Micro exam of the nodule shows fibrous CT, M∅, multinucleated giant cells, fibroblasts, a few lymphocytes, & scattered fragments of polarizable foreign material. Which of the following substances that promotes fibroblast migration & proliferation most likely led to this lesion? (TGF-β OR TNF-α) The pt has another mutation that was not included in the previous analysis -For a pt to exhibit symptoms in CF they must have two dysfunctional alleles, which must be on the same gene The pt has a mutation in another gene for a protein that interacts w/ CFTR -CF is a AR disorder so two non-functional mutations are needed to see symptoms -If the pt has a mutation in a different gene she would not have symptoms A 3-week-old F newborn, presents for a follow-up exam after the results of a newborn screening showed an increase serum conc of immunoreactive trypsin. CF is suspected. At 4-months, her sweat chloride conc is 60mmol/L (N40). Molecular analysis that includes a panel pf the 70 most common CF transmembrane gene mutations is done. Results shows a mutation in one allele. Which of the following best explains the findings in this pt? (The pt has another mutation that was not included in the previous analysis OR The pt has a mutation in another gene for a protein that interacts w/ CFTR) G2 -DNA synthesis & mitosis G1 -Cells increase in size & get ready for DNA replication -Retinoblastoma & osteosarcoma affect here S -DNA replication occurs In which of the following stages of the cell cycle are mitotic cyclins synthesized? (S OR G2 OR G1) Granulation tissue -Pic shows granulation tissue -Also, 18 days after MI we would expect to see granulation tissue not granulomas A 52M, is admitted to the hospital for tmt of a massive acute MI. Tmt w/O2, β-blockers, aspirin, & reperfusion therapy is initiated. 18 days later, he develops v-fib, from which he cannot be resuscitated. A photomicrograph of cardiac tissue from the site of infarct obtained at autopsy is shown. Which of the following best describes the appearance of this pt's heart? (Granulation tissue OR Granuloma) 1 in 4 will have 25% β-globin function & may require occasional transfusions -Use punnet square, works out to 1 in 4 will be affected -Father → A A(not functional) -Mom → A a(affected) -Heme holds 4 so all expect one would be affected A 26M & his 25F, present for genetic counseling prior tp conception. both pts were previously found to have a microcytic anemia & an increased fraction of Hemoglobin A2. Genetic analysis shows that the man has a Hz null mutation of the β-globin gene, & the woman has a Hz mutation known to cause a 50% decrease in β-globin gene function of one allele. Which of the following best represents the β-globin function possibilities for this couple's offspring? (1 in 4 will have 25% β-globin function & may require occasional transfusions OR 1 in 2 will have 50% β-globin function w/out need for transfusions) Post-translational modification -Used in protein modification -Used to convert pro-hormones → hormones Alternative splicing -Used for gene expression (not protein modification) to make protein (not modify it) An experimental study is conducted to examine the function of the pro-opiomelanocortin gene. The gene is found to encode an mRNA from which protein products are generated. This protein serves as the precursor of ACTH hormone & β-lipotropin. Which of the following processes is necessary in order to generate these hormones? (Alternative splicing OR Post-translation modification) Lamins -Intermediate filaments, fibrous proteins that provide structural function & transcriptional regulation in the cell nucleus Tubulin -Used to make microtubules Which of the following terms best describes the fibrous proteins that form the two-dimensional network on the inner surface of the nuclear membrane? (Lamins OR Tubulin) GnG -Pt has an issue making glucose via the GnG pathway → we know this b/c when given Glycerol or Fructose his blood sugar is not elevated (which if should be he could make glucose) -However, when galactose is given his blood sugar rises (galactose is basically converted to glucose almost immediately) A 3-month-old B, presents to the ED d/t SOB & listlessness for 3 hrs. He has had an upper RTI & has eaten poorly for the past 3 days. Temp is 98.6F, & RR are 30/min. PE shows lethargy & mild hepatomegaly. Labs show hypoglycemia, lactic acidemia, ketonemia, & metabolic acidosis. Following administration of glycerol or fructose on different days, his serum glucose conc do not increase. However, they do increase normally after the IV administration of galactose. A defect in which of the following liver metabolic pathways is the most likely cause of these findings? (FA oxidation OR GnG) Scar formation -OI usually affects type I collagen → type I collagen is seen in scar tissue Granulation tissue -Type III collagen → highly vascular tissue made up of small blood vessels, fibroblasts, & myofibroblasts - first phase of would repair A 4F, with OI has impaired wound healing. Which of the following components of wound healing is most likely to be affected as a direct result of her underlying disease? (Granulation tissue deposition OR Scar formation) Na+ -Blocks sodium channels -Causes paraesthesia of the lips & tongue, mouth tingling -followed be paresthesias in the extremities, hypersalivation, sweating, bradycardia, headache, weakness A 30M, develops tingling around the lips & mouth after consuming a small portion of fugu (puffer fish) in a Japanese restaurant. The liver of this fish contains tetrodotoxin, a substance that causes cardiac arrest when consumed in high doses. This pt's symptoms are most likely d/t the blocking action of tetrodotoxin on which of the following ion channels? (Na+ OR Ca+) Doxorubicin -Pt presents w/dilated cardiomyopathy → which presents w/: 1-SOB 2-Dyspnea on exertion 2-Narrow pulse pressure, systolic regurg murmur in presence of S3 3-pleural effusions & edema (Bibasilar crackles d/t fluid buildup 4-Orthopnea 5-Enlarged heart 6-Arrhythmias Bleomycin -cause of pulmonary fibrosis → which presents w/: 1-SOB 2-Dry cough 3-Fatigue 4-Unexplained wt loss 5-Aching muscles & joints 6-Clubbing of finger After completing 6 courses of chemo for cancer of the breast, a 45F, has SOB, dyspnea on exertion, & orthopnea. Basilar crackles are heard bilaterally, & there is an S3 gallop. CXR shows an enlarged heart, bilateral interstitial & alveolar edema, & bilateral pleural effusions. Which of the following is the chemo drug most likely to have caused these findings? (Bleomycin OR Doxorubicin) Increased Angio II conc -ARB stands for angio II receptor blocker A person is started on Losartan tmt. Which of the following is most likely to occur in this pt? (Increased aldosterone conc OR Increased Angio II conc) Increased Lymph flow -Histamine directly stimulates lymphatic vessel contraction which would ↑ lymph flow Decrease in hydrostatic interstitial pressure -Histamine ↑ the permeability of capillaries → which allows more blood to flow in leading to an ↑ in interstitial hydrostatic pressure A 24M, receives an injection of histamine in the brachial artery. Which of the following changes is most likely to occur in his forearm in response to the histamine? (Decreased interstitial hydrostatic pressure OR Increased Lymph flow) Palpable RV lift -The values show that there is blood mixing between the RV & LV → this is causing the pressure in the RV to increase to match the same pressure in the LV → this would cause a palpable RV lift Diastolic murmur -Would only occur w/ 1-Aortic regurg 2-Mitral/tricuspid stenosis -Neither would be seen in this pt A 10F, w/ a lifelong Hx of intermittent dyspnea presents for a follow-up. During an episode of dyspnea, she turns blue. The episode resolves after she squats. A systolic murmur was heard at birth. Today, a grade 4/6 systolic murmur is heard at the pulmonic area, radiating widely to the back & left side. Cardiac catheterization shows: -Aorta------82% -VC--------70% -Pul artery--70% -RA--------70% -LA--------95% -RV--------70% -LV--------82% Which of the following is most likely in this pt? (Diastolic murmur OR Palpable RV lift) Adenosine -Potent vasodilator at the organ level Prostacyclin (PGI2) -Involved in homeostasis → inhibits platelet activation Prostaglandin F2 -Carboprost → used as abortifacient to induce labor A 28M, has a BP cuff placed around his left arm; the cuff in inflated to totally occlude the arterial blood flow for 2 mins & is then removed. BF in the left arm increases by 50% during the next 3 mins & then decreases to control values. Which of the following humoral substances is most likely involved? (Adenosine OR PGI2) SVR(↑), PVR(↓), PCWP (↑) -In cardiogenic shock the: 1-SVR is always increased 2-PVR always decreased (d/t vasodilation) 3-PCWP → can be either (↑/↓) A 65M, present to ED 30 mins after sudden onset of SOB & chest discomfort in his chest. He says he feels weak & apprehensive. His pulse is 110/min, RR is 22/min, BP is 100/80. PE shows diaphoresis. An ECG shows ST elevation in the anterior leads. Compared w/a healthy man of the same age, which of the following sets of cardiopulmonary changes is most likely in the pt? (SVR(↑), PVR(↓), PCWP(↑) OR SVR(↑), PVR(↑), PCWP(↓) Decreased blood volume -Bed rest leads to an elevated HR → despite an elevated HR, VO2 max is reduced from decreased SV & CO as a result from decreased VR associated w/lower circulating blood volume An otherwise healthy 35M, sustains a fracture of the left pelvis in a MVC. A 3-week period of bed rest for this pt is most likely to cause which of the following physiological changes? (Decreased blood volume OR Decreased plasma sodium volume) Polyneuropathy -May present w/: 1-Numbness, weakness, or burning pain 2-presents on the same areas on both sides of body 3-Usually presents in distal → proximal pattern Syringomyelia -Most common in the 3rd & 4th decades of life [pt is 19] → presents w/: 1-Firs symptom → Loss of pain & temp in cape like distribution (back & arms) 2-Flaccid paralysis 3-Decreased deep tendon reflexes 4-Fasciculations A 19M, has had weakness of the muscles of her neck & extremities for the past week. Bladder & bowel function is normal. Position sense is impaired. Which of the following is the most likely Dx? (Polyneuropathy OR Syringomyelia) Pineal gland -Vertical gaze palsies are most commonly caused by a lesion in midbrain → the pineal gland is in close proximity to the midbrain PPRF -Would present as horizontal gaze palsy A 22F, present b/c of nausea & vomiting for 1 wk. She has a 6-month Hx of headaches. She works as a data entry tech & has recently found it difficult to focus on the text. She also has had trouble looking up from her desk at the clock on the wall w/out moving her head. Neuro exam shows marked vertical gaze palsy & impaired accommodation. Horizontal gaze is normal. An MRI of the brain is most likely to show a tumor at which of the following locations? (Pineal gland OR PPRF) Presenilin -Early onset AZ is associated w/: 1-Presenilin-1 gene on Ch14 2-Presenilin-2 gene on Ch1 -Presenilin is associated w/*degrading Amyloid-β proteins* Amyloid A & β2 microglobulin -Early onset AZ is associated w/ Amyloid β precursor protein (AβPP) gene on chromosome 21 [Not Amyloid A or β2 micro globulin] A 56 year old pt dies from complications associated w/ Alzheimers. This disorder most likely indicates a mutation in a gene encoding for which of the following proteins? (β2 microglobulin OR Presenilin OR Amyloid A) Inhalant abuse -Signs include: 1-Bilateral injected conjunctivae 2-Runny nose 3-Unusual smelling breath 4-loss of appetite 5-Anxiety 6-Sores around mouth Impetigo -Usually presents in kids aged 2-5 [pt is 12] -Would present as bullous impetigo on non-bullous impetigo (single lesion) RF include: 1-Poverty 2-Crowding 3-Poor hygiene 5-Underlying scabies infection A 12B, presents b/c of a persistent rash around his nose & mouth for 4 months. He has also had a decreased appetite & an unintentional wt loss (10-lbs) during the past 3 months. His mother states, "The rash developed shortly after he started at his new school. I wonder if he keeps getting into something. I've tried hydrocortisone cream, but it didn't work." She adds, "And now his grades are failing, & he's not eating as much as he used to. I hope he's not depressed b/c of the rash." The rash began as mild redness & then became dry & started to flake. The pt says there is no pain or discomfort w/the rash. PE shows injection of both conjunctivae, an eczematous eruption extending inferiorly from the nasolabial fold to the upper lip, & erythematous nasal mucosa that is friable w/gold stippling. When asked, he states that his mood is fine. Which of the following is the most likely cause of this pt's condition? (Impetigo OR Inhalant abuse) Hyporeflexia -"B" Is the dorsal root ganglion → it contains the Afferent limbs for the reflex arc → damage to these cells results in Hyporeflexia Fibrillations -would be seen if damage was to the area labeled D A 60F, is receiving cisplatin for advanced transitional cell carcinoma. She develops paresthesias, & the med is stopped. The med likely damaged the largest cells in the region labeled "B" in the diagram. The damage to the cells would most likely lead to which of the following motor signs? (Fibrillations OR Hyporeflexia) Lower motor neurons -Pt presents w/ all the classic lower motor neuron signs & symptoms Internal capsule -Cant be internal capsules b/c pt would present w/UMN syndrome → she would not have fasciculations, atrophy, and weakness A 55F, presents d/t a 3-month Hx of difficulty using her hands & a 3-wks Hx of muscle cramps. She has had a 20-lbs wt loss during the past 5-wks. Neuro exam, shows tongue fasciculations & LE weakness & atrophy. Sensory exam is normal. A lesion at which of the following sites is the most likely cause of these findings? (Internal capsule OR Lower motor neurons) Fusion of the sclerotomes Immediately after spontaneous vaginal delivery, a full-term male newborn is found to have a tuft of hair midline in the lumbar region. Palpation of the area shows an absence of spinous processes in that region. Imaging studies show no additional abnormalities. The most likely cause of this defect was failure of which of the following events during gestation? (Formation of the neural tube OR Fusion of the sclerotomes) Neural crest cells -Vestibular schwannomas (acoustic neuromas) -S-100+ made from neural crest cells Glioblasts -Would be a glioblastoma A 59F, has a 10-yrs Hx of progressive right-sided hearing loss. An MRI of the head shows a large cerebellopontine angle mass that has compressed the vestibulocochlear nn on the right. The mass most likely arose from which of the following cells types? (Glioblasts OR Neural crest cells) Synaptobrevin -Pt presents w/Tetanus (lockjaw) → presents w/ 1-Spasms of Jaw that then progress to the entire body (Chest, neck, back, Abd muscles, buttocks - may all be affected) 2-Fever, headache, sweating 3-Trouble swallowing 4-HTN 5-Tachycardia Pathophysio -Toxin blocks inhibitory neurotransmitters glycine & GABA across the synoptic cleft → nerve impulses are not inhibited so spasms occur → Toxin cleaves Synaptobrevin II & prevents the release of neurotransmitters Acetocholinesterase -Botulism binds to nerves which use ACh (not esterase) → toxin cleaves SNARE proteins [not synaptobrevin] A 37M, farmworker presents to the ED b/c of a 12-hrs Hx of severe pain in his abdomen & legs & painful spasms of the jaw. PE shows marked spasms of the maseter & abd musculature. During the exam, a loud noise in the exam room triggers a painful spasm & respiratory compromise requiring intubation. Administration of antitoxin prevents further symptoms, but the pt continues to require sedation & ventilatory support for the