periodic acid-Schiff stain

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per·i·od·ic ac·id-·Schiff stain (PAS),

a tissue-staining procedure in which 1,2-glycol groupings are first oxidized with periodic acid to aldehydes that then react with the sulfite leucofuchsin reagent of Schiff and turn red-violet; strong staining occurs with polysaccharides, such as glycogen, and mucopolysaccharides of epithelial mucins, basement membranes, and connective tissue.
Synonym(s): PAS stain


Hugo, German chemist in Florence, 1834-1915.
Kasten fluorescent Schiff reagents - see under Kasten
ninhydrin-Schiff stain for proteins
periodic acid-Schiff stain - a tissue-staining procedure. Synonym(s): PAS stain
Schiff base - condensation products of aldehydes and ketones with primary amine. Synonym(s): aldimine
Schiff reagent - used for aldehydes and in histochemistry to detect polysaccharides, DNA, and proteins.

per·i·od·ic ac·id-Schiff stain

(PAS) (pērē-odik asid shif stān)
A clinical tissue-staining procedure.
References in periodicals archive ?
The results of the periodic acid-Schiff stain (Figure 1, A through C) for tissue glycogen showed basement-membrane thickening in connective tissues and basal laminae in FBMN, but in FSGS, it revealed a well-delineated, rounded glomerulosclerosis that adhered to the Bowman capsule, with the appearance of a small fibrosis.
Psammomatous calcification (A) and periodic acid-Schiff stain positive hyaline bodies (B) were seen in the tumour stroma (arrowed) (x100).
The periodic acid-Schiff stain did not demonstrate cytoplasmic staining of the cells in the epidermis.
And if you do a biopsy, always do a periodic acid-Schiff stain on the specimen," Dr.
Fungal elements were visible on periodic acid-Schiff stain.
Characteristically, the tumor cells were densely pigmented with melanin, which was positive for Fontana-Masson (Figure 3) and periodic acid-Schiff stains but negative for Berlin-blue stain.
Because hyaluronidase-sensitive material may be encountered in mesotheliomas, digested periodic acid-Schiff stains have been recommended for neutral ("epithelial") mucins because this finding is almost entirely restricted to adenocarcinoma.
Paraffin-embedded tissues from endobronchial biopsies, TBB, and postmortem lung samples were studied histologically using hematoxylin-eosin, Giemsa, and periodic acid-Schiff stains.
These organisms were gram-negative and highlighted by Warthin-Starry (Figure 4) and periodic acid-Schiff stains.
No hyaline globules were seen in the endothelial cells on hematoxylin-eosin or periodic acid-Schiff stains.