This is a combined method utilising the properties of both the PAS (see PAS) and Alcian blue (see Alcian blue) methods to demonstrate the full complement of tissue proteoglycans.
The rationale of the technique is that by first staining all the acidic mucins with Alcian blue, those remaining acidic mucins which are also PAS positive will be chemically blocked and will not react further during the technique. Those neutral mucins which are solely PAS positive will subsequently be demonstrated in a contrasting manner. Where mixtures occur, the resultant colour will depend upon the dominant moiety.
The combined result from the port-manteau method demonstrates both acidic- neutral- and mixtures of acidic and neutral mucins.
1. Diastase pre-treatment may be used to eliminate the presence of glycogen, prior to staining in Alcian blue.
2. Fixation not-critical, however fixation by aldehyde addition, eg glutaraldehyde, will produce non specific general PAS positivity.
Bring sections to distilled water.
Stain with Alcian blue 15 mins
Wash well in running tap water 2 mins
Rinse in distilled water
Treat with periodic acid 5 mins
Wash well in distilled water
Stain with Schiff's reagent 10 mins
Wash well in running tap water 5 mins
Stain nuclei with haematoxylin 1 min
Wash in running tap water 2 mins
Differentiate with acid alcohol
Wash and blue nuclei in Scott’s tap water
Wash in water
Dehydrate, clear and mount
acidic mucins ............................... blue
1. 1% Alcian blue in 3% aq acetic acid (see Alcian blue)
2. 0.5% aq periodic acid
3. Schiff's reagent (see PAS)