Effect of human basic fibroblast growth factor on fibroblast proliferation, cell volume, collagen lattice contraction: in comparison with acidic type.

Human recombinant basic fibroblast growth factor (bFGF) is a potent mitogen for normal human dermal fibroblasts in the presence of heparin which binds to and stabilizes it. The optimal mitotic response is obtained with a concentration of 1 ng/ml of bFGF in monolayer cultures (non-differentiated fibroblasts) as well as in the better-differentiated fibroblasts obtained through the 'collagen lattices' culture system (fibroblasts embedded in a 3-dimensional collagen gel) achieving a doubling of the cell number in 8 days. Despite increasing the number of cells, bFGF decreases the ability of fibroblasts to contract collagen fibers.

Normal Merkel cells express a synaptophysin-like immunoreactivity.

Synaptophysin (SY), a specific component of the membrane of presynaptic vesicles, has been reported as a novel marker for neurons, certain neuroendocrine cells and their neoplasms including neuroendocrine carcinomas of the skin. The origin of the Merkel cells (MC) being far from clear, this study was performed to establish if normal MC express SY. It is demonstrated by immunofluorescence and immunoelectron microscopy using a monoclonal antibody SY38 to this glycoprotein that normal MC in man, rabbit and pigs express an SY-like reactivity.