Scanning electron microscopic observations on cells grown in vitro. V. Human diploid cells can attach also with their upper surface.

When small glass particles are seeded on top of human diploid cells in a monolayer the cells attach firmly to the glass with their upper surface. In combination with this attachment fingerlike protrusions and small leading lamellae are formed de novo from the normally completely protrusion-free upper surface. These results are in contradition to findings from Vasiliev and Gelfand [10]. Our results indicate that attachment and adhesiveness must not unequivocally be in relation to the presence and formation of cellular protrusions.