IHC of MCT1 in serial 6-μm sections of frozen human muscle after immersion in various fixatives for 30 min at 4C. (A) Unfixed section; (C) methanol, same field; (D) acetone, same field; (B) unfixed section, primary antibody omitted, different field, light decreased to increase refractive effects. Asterisks identify the same fibers in A, C, D. (E-H) A different field; again, the asterisks identify the same fibers in all four sections. (E) unfixed section; (F) formalin; (G) methanol; (H) ethanol. The essential feature for comparison is the plasmalemmal staining, not the cytoplasmic staining.