A 72-year-old man develops muscle wasting in his lower limbs…

A 72-year-old man develops muscle wasting in his lower limbs after being immobilized for 4 weeks due to a pelvic fracture. Microscopic evaluation reveals reduced cell size and increased activity of the ubiquitin-proteasome system. Which of the following best characterizes this type of cellular adaptation?

A 58-year-old man receives a kidney transplant. Two weeks la…

A 58-year-old man receives a kidney transplant. Two weeks later, his creatinine levels rise and a biopsy reveals infiltration of lymphocytes and evidence of vascular injury in the transplanted kidney. Which of the following best explains the immunologic basis of this reaction?