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 ?
c) Rare, small diastaseresistant globular inclusions, PAS stain with diastase.
PAS stain further identified ribbon like, non-septate hyphae along with developing spores (Figures 6).
PAS stain showed an enlarged intracytoplasmic band with PAS positive granules in the apical pole of enterocytes in contrast to the thin uniform linear staining of the brush border in the normal mucosa (Figs.
The PAS stain demonstrated moderate amounts of glycogen within the cytoplasm of the tumour cells.
Analysis of human erythrocyte membranes isolated by SDS-PAGE followed by PAS stain, revealed the presence of four SGPs and initially identified as PAS-1, PAS-2 and PAS-3 bands (Fairbanks et al.
The PAS stain showed indistinct checker board pattern in which muscle fibers are deeply and lightly stained positive (Fig.
uveitis systemic steroids PAS stain 1 -- No + 2 -- No + 3 + Yes + 4 -- Yes + 5 + Yes + 6 + Yes + 7 -- Yes + 8 + Yes + 9 NR NR ND 10 + Yes ND 11 + Yes ND 12 NR NR ND 13 -- No ND 14 -- No ND 15 -- Yes ND 16 + Yes ND 17 + Yes ND 18 + Yes ND 19 + Yes ND Patient.
Also the PAS stain was particularly useful when applied to whole mounts from Atlantic cod making it easier to identify the outline of small POFs compared to PVF that were less intensely stained.
A Congo red stain (for amyloid) was negative and a PAS stain (for mucin) was positive (Fig.
Cytoplasmic glycogen can often be detected by PAS stain or electron microscopy.
After one month of the primary operation, some brain tissue was taken out with a small elliptical incision under local anaesthesia for serial histological evaluation by Haematoxylin and Eosin stain, (10) PAS stain, (11) Van Gieson stain, (12) Gomori stain, (13) Giemsa stain, (14) etc.
PAS stain revealed numerous tangles of fungal hyphae, both in the necrotic areas (Fig.