(1993) Binding of L-selectin to the vascular sialomucin
Rat Muc4 (sialomucin
complex) reduces binding of anti-ErbB2 antibodies to tumor cell surfaces, a potential mechanism for herceptin resistance.
Potentiation of metastasis by cell surface sialomucin
complex (rat MUC4), a multifunctional anti-adhesive glycoprotein.
complex) expression in alivary gland tumors and squamous cell carcinoma of the upper aerodigestive tract.
Support for the latter includes (1) presence of neutral mucins, acidic sulphomucins, and sialomucins
within the villous adenoma and in cystitis glandularis (6) and (2) a similar genetic makeup between villous adenoma and the dysplastic regions of flat metaplastic mucosa.
After being deparaffinised and hydrated, the sections were stained with hematoxylin-eosin (HandE) and Masson's trichrome stain to determine the general structure of stomach regions, the periodic acid schiff (PAS) for determinating neutral mucins, glycogen, and other periodate reactive carbohydrates (sialidaselabile, sialomucins
and weakly sulphated mucins), alcian blue (pH 2.5) for identifyi ng acidic mucins, alcian blue (pH 2.5)- Periodic acid Schiff (PAS) for differentiating acidic and neutral mucins, combined aldehyde fuchsin- alcian blue (pH 2.5) (AF-AB) for differentiating of acidic mucins with sulphate and carboxyl groups.
With AF-AB staining few acini are stained blue showing presence of sialomucins
while very few are stained purple confirming the presence of very few sulfomucins.
In normal gastrointestinal mucosa, sulfomucins are present exclusively in the colon compared to the complete exclusion of the small intestine, where sialomucins
are produced.10 However few previous reports have shown that the mucin present in the metaplastic mucosa of ileostomies is colonic type.5,6
Moreover, YST cell cytoplasm may stain with PAS due to glycogen content but never with mucicarmine since mucicarmine stains acidic sialomucins
Since phenylhydrazine blocks specially the aldehyde produced by neutral glycoprotein, only the aldehyde formed by sialomucins
and sulfomucins remain reactive to PAS (Pearse; Bancroft & Cook).
Glickman et al (8) evaluated multilayered epithelium in samples obtained from 17 patients and found that its glandular cells expressed neutral mucins, sialomucins
, and sulfomucins at rates comparable to Barrett esophagus (88%, 100%, and 71% of cases, respectively, versus 100%, 100%, and 76%, respectively).
A variable proportion of cells have intracytoplasmic lumina containing demonstrable sialomucins
with the mucicarmine and Alcian blue stains.