Histopathology.
Twelve mice were examined for gross and histologic abnormalities, including one male and one female MCAD−/− mouse 18-mo-old, one male and one female MCAD+/+ mouse 6-mo-old, two male and two female MCAD−/− mice 4-wk-old, and two male and two female MCAD+/+ mice 4-wk-old. Kidney, spleen, pancreas, liver, brain, heart, testicles, ovaries, and skeletal muscle were fixed by immersion in buffered 10% formalin, processed routinely for paraffin sectioning, sectioned at 5 μm, and stained with hematoxylin and eosin. Frozen liver sections were prepared using standard methods and sections were stained with Oil-red-O. Slides were examined without knowledge of genotype or age. Other mice were examined because of sporadic clinical disease. Those with visible cardiac enlargement were evaluated for cardiac lesions.