Different expression of the catalytic alpha subunits of the AMP activated protein kinase--an immunohistochemical study in human tissue.

AMPK is an ubiquitously distributed multienzyme complex. It is an important energy sensor and regulator of cellular metabolic activity. In this study we analyzed for the first time the cellular distribution of the catalytically active subunits AMPKα1 and α2 in different human tissues by immunohistochemistry. We found different expression patterns for both isoforms. AMPKα2 expression clearly dominates in skeletal myocytes and cardiomyocytes, whereas AMPKα1 dominates in a number of secreting cells, like mammary glands, islets of langerhans and cells of the colon crypts.

A novel method for processing resin-embedded specimens with metal implants for immunohistochemical labelling.

A major technical problem in the processing of resin-embedded tissues is the adhesion of the tissue sample on glass slides for immunohistochemical labelling. We therefore established a novel protocol for processing such specimens with improved attachment of the tissue sample during resin removal (deplastification). In order to demonstrate the feasibility of the procedure we employed a panel of smooth muscle cell maturation markers. The technique makes use of a silicone glue (Elastosil E41; Wacker Chemie, München, Germany) to attach the tissue samples to the glass slides. This allows resin dissolution in xylene/2-methoxyethylacetate without detachment of the sample from the slide. Our results demonstrate successful immunohistochemical labelling with primary antibodies directed against: smooth muscle actin, smooth muscle myosin, h-caldesmon, desmin, vimentin and von Willebrand factor. In conclusion, we have established a new and successful method for resin-embedded sample adhesion on glass slides. The developed protocol is feasible for investigation of cells which are involved in intimal proliferation following stent implantation.