A 40-year-old man is pulled from the ocean after a boating accident and resuscitated. Six hours later, the patient develops acute renal failure. Kidney biopsy reveals evidence of karyorrhexis and karyolysis in renal tubular epithelial cells. Which of the following biochemical events preceded these pathologic changes?

Decrease in intracellular pH. During periods of ischemia, anaerobic glycolysis leads to the overproduction of lactate and a decrease in intracellular pH. Lack of O2 during myocardial ischemia blocks the production of ATP Pyruvate is reduced to lactate in the cytosol and lowers intracellular pH. The acidification of the cytosol initiates a downward spiral of events that propels the cell toward necrosis. The other choices point to changes in the opposite direction of what would be expected in irreversible cell injury.Diagnosis: Acute tubular necrosis