Table 1. Effect of different fixation agents and fixation methods on antigen detection.

fixation solution	antigen preservation	morphology	number of animals
perfusion fixation			8
• Bouin solution	+ +(+)	+ + +	2
• Acid formalin (4%)	+ + (+)	+ + +	3
• Neutral buffered formalin (10%)	+ +	+ + +	3
immersion fixation			24
• Bouin solution	+ +	+ + (+)	2
• acid formalin (4%)	+ +	+ + (+)	6
• neutral buffered formalin (10%)	+ (+)	+ + (+)	6
• Carnoy-fixation	− −	+ +	2
• Zinc-fixation	+ (+)	−	2
• Glyo Fixx (Shandon)	+	+ +	2
• Zinc Formal-Fixx (Shandon)	(+)	+ +	2
• Notox Histological Fixative (Quartett)	−/+	+ +	2

To establish the immunohistochemical detection of CK1δ several fixation methods and fixatives had been used. Paraffin embedded tissue sections were immunostained for CK1δ using different fixation solutions and fixation methods. Comparison of the perfusion with the immersion fixation method revealed only slight regional differences in the preservation of CK1δ and in the morphology of the tissue especially when acidic formalin or Bouin's fluid were used as fixatives. − no effect on antigen detection or morphology; + weak effect on antigen detection or morphology; ++ medium effect on antigen detection or morphology ; +++ strong effect on antigen detection or morphology. (+) indicates intermediate effect, for instance ++(+) indicates intermediate level between medium and strong effect.