A 78-year-old man dies suddenly from complications of acute kidney failure. An autopsy is performed and microscopic evaluation of the kidneys shows pale, swollen cells in the proximal convoluted tubules. Microscopic evaluation of the liver shows similar findings. Which of the following is the most likely underlying mechanism of these findings?
ADouble-stranded DNA breakage
BImpaired Na+/K+-ATPase pump activity
CFree radical formation
DCytochrome C release
ECytoplasmic triglyceride accumulation
An 84-year-old man is brought to the physician by the staff of a group home where he resides because of worsening confusion and decreased urinary output. His nurse reports that the patient has not been drinking much for the last 3 days. Examination shows a decreased skin turgor and dry oral mucosa. His pulse is 105/min and blood pressure is 100/65 mm Hg. His serum creatinine is 3.1 mg/dL and a urea nitrogen is 42 mg/dL. Urine studies show multiple brownish granular casts. Which of the following processes is most likely involved in the pathogenesis of this patient's condition?
AImmune complex deposition in mesangium
BLeukocytic infiltration of renal interstitium
CNecrosis of renal papillae
DNecrosis of tubular epithelial cells
EDisruption of glomerular podocytes
Nine days after being treated for a perforated gastric ulcer and sepsis, a 78-year-old woman develops decreased urinary output and malaise. She required emergency laparotomy and was subsequently treated in the intensive care unit for sepsis. Blood cultures grew Pseudomonas aeruginosa. The patient was treated with ceftazidime and gentamicin. She has type 2 diabetes mellitus, arterial hypertension, and osteoarthritis of the hips. Prior to admission, her medications were insulin, ramipril, and ibuprofen. Her temperature is 37.3°C (99.1°F), pulse is 80/min, and blood pressure is 115/75 mm Hg. Examination shows a healing surgical incision in the upper abdomen. Laboratory studies show: Hemoglobin count 14 g/dL Leukocyte count 16,400 mm3 Segmented neutrophils 60% Eosinophils 2% Lymphocytes 30% Monocytes 6% Platelet count 260,000 mm3 Serum Na+ 137 mEq/L Cl- 102 mEq/L K+ 5.1 mEq/L Urea nitrogen 25 mg/dL Creatinine 4.2 mg/dL Fractional excretion of sodium is 2.1%. Which of the following findings on urinalysis is most likely associated with this patient's condition?
ARBC casts
BWBC casts
CWaxy casts
DMuddy brown casts
EPigmented casts
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