Figure 2.

 Staining for sialic acid. Control (A) case 7 showed faint brush border and goblet cell stain for sialic acid. (B) Stain for acetylated sialic acid showing the same pattern as in (A) but more strongly stained. Microvillous atrophy (case 2). (C) Stain for sialic acid showing similar distribution to alcian blue/periodic acid-Schiff stain. (D) Positive staining for acetylated sialic acid in apical cytoplasm and goblet cells. (E) Reduced staining following sulphuric acid digestion confirming the presence of acetylated sialic acid.