Practice Test 12 - USMLE Step 1
20 questions. Answer them in any order, then submit to see your score and every explanation.
- The increased delivery of NaCl to the macula densa cells will trigger which of the following immediate responses as part of the tubuloglomerular feedback mechanism?
- A 35-year-old man has fever and graft tenderness 2 weeks after kidney transplant; creatinine is 3.0 mg/dL and Doppler is normal; he takes tacrolimus and mycophenolate. What is the most appropriate next step in management?
- The first heart sound (S1) is produced by the closure of which pair of valves?
- Given the slow-growing nature of the suspected organism, which medium will be incubated for up to 8 weeks to allow for growth?
- Which of the following hemodynamic changes is the most direct consequence of her underlying valvular lesion?
- A physiologist studies uterine spiral artery blood flow in late pregnancy and finds that local prostaglandin production is high. She administers indomethacin to a pregnant sheep and observes constriction of the ductus arteriosus in the fetus. Which of the following best explains why maternal non-steroidal anti-inflammatory drug (NSAID) therapy can lead to premature closure of the human fetal ductus arteriosus?
- A biopsy of this patient's thyroid gland would most likely reveal which of the following histologic findings?
- A case–control study matches each sepsis case with a control patient of the same age and sex. Investigators record whether each subject had an indwelling catheter during the previous week (yes/no). Which test is most appropriate to determine if catheter use is associated with sepsis in the matched pairs?
- Glucocorticoids are effective in treating acute rejection primarily through which of the following mechanisms?
- This maneuver is intended to transiently increase which of the following hemodynamic parameters to improve blood pressure?
- Which structural feature of Norovirus most contributes to its stability and ease of transmission via fomites and contaminated food?
- What is the mechanism of action of fomepizole in this setting?
- The enzyme responsible for converting homocysteine to methionine in this patient requires which of the following as a cofactor?
- Which of the following is the most appropriate interpretation of these findings?
- Which of the following is the most likely cause of this patient's electrolyte and acid-base disturbance?
- This study is primarily designed to measure which of the following test characteristics?
- This patient's syndrome is most likely caused by a tumor secreting which of the following hormones?
- Which virulence factor of this organism is antiphagocytic and shares antigenic similarity with human cardiac myosin, leading to this autoimmune complication?
- This fatal disorder results from a defect in the biogenesis of which cellular organelle?
- Which of the following best describes the fundamental immunologic defect in this patient?