1 Introduction.- 1.1 The Cytokeratins as a Member of the Intermediate Filament Protein Family.- 1.2 Coexpression of Intermediate Filaments.- 1.3 The Aim of This Study.- 2 Methodological Aspects.- 3 Fetal Development of Neuroectodermal Structures.- 4 Choroid Plexus and Ependyma.- 5 The Subcommissural Organ.- 6 Ciliary and Retinal Pigment Epithelia of the Eye.- 7 Heterogeneity in the Immunolocalization of Cytokeratin-Specific Monoclonal Antibodies in Neuroectodermal Structures.- 8 The Arachnoidea.- 9 Pituitary Gland Epithelia and Adenomas.- 9.1 Endocrine Cells and Pituitary Adenomas.- 9.2 Folliculostellate Cells and Rathke's Cysts.- 10 Cytokeratin in Glial Cells and in Tumors of Glial Origin.- 11 Cytokeratins in Nerve Cells.- 12 Neural Crest Derivatives.- 13 Cytokeratin Expression in Tumors of Neuroectodermal Origin.- 14 Implications on Cell Function and Differentation.- 15 Conclusions.- 16 Summary.- Refference.- Note Added in proof.
