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PAS - Periodic Acid (Schiff) Stain kit
Кит за оцветяване PAS
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This kit is used for the histochemical staining of peripheral blood and bone marrow smears, and for carbohydrate radicles (e.g. Glycogen)
Content:
Feulgen Stain (Schiff) - 100 ml
Periodic Acid Solution - 250 ml
Haemalaum Mayers Solution - 100 ml
Results:
Positive P.A.S. substances.....magenta red
Nuclei............................................blue
 Principle
Periodic acid oxidizes selectively the following groups: 1,2 glycolic; primary aminic (1-hydroxy-2-aminic); secondary aminic (1-hydroxy-2-alkylaminic); 1-hydroxy-2-ketonic. Some methoxyl derivatives and alpha-ketones are oxidized as well, but they are not converted to aldehydes. During oxidating process the links between carbon atoms in 1,2 position break and consequently aldehydic groups are formed. In the following reaction, sulphurous fuchsin in Schiff reagent changes these 2 contiguous aldehydic groups into a insoluble stained compound similar to basic fuchsin. Three conditions are necessary for these reactions to take place:
1) hydroxylic groups must be free,
2) the compounds which form after oxidation must not spread in the tissue,
3) there must be enough aldehydic groups in the compounds for a histochemical survey.
Only macromolecules such as glycans and mucins are able to meet these demands. Periodic acid has been chosen as oxidizer because it arrests oxidation at aldehydic phase. Acid glycans do not react, except for monosulphuric heparin, since the presence of -SO3H group blocks reactive glycolic groups. |
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