text: <unk> <unk><unk>  (PAS) is a<unk> ing method used in histology and pathology. This method is primarily used to identify glycogen in tissues. The reaction of<unk> <unk>  selectively oxidizes the glucose residues, creates aldehydes that react with the<unk>  reagent and creates a purple-magenta color. A suitable basic<unk>  is often used as a counterstain.<unk> ing is mainly used for<unk> ing structures containing high proportion of carbohydrate macromolecules (glycogen, glycoprotein, proteoglycans), typically found in eg. connective tissues, mucus, and basal laminae.<unk> ing can be used to distinguish between different types of glycogen storage diseases.
option_0: Periodic acid-Schiff stain
option_1: Silver stain
option_2: Dark field microscopy
option_3: Microscopy
option_4: Immunofluorescence
option_5: Lauge-Hansen classification
option_6: Fluorescence in situ hybridization
option_7: Seidel test