Glial and Neuronal Marker Proteins in the Silicone Chamber Model for Nerve Regeneration

Abstract: In the present study, neuronal and Schwann cell marker proteins were used to biochemically characterize the spatiotemporal progress of degeneration/regeneration in the silicone chamber model for nerve regeneration. Rat sciatic nerves were transected and the proximal and distal stumps were inserted into a bridging silicone chamber with a 10-mm interstump gap. Using dot immunobinding assays, S-100 protein and neuronal intermediate filament polypeptides were measured in different parts of the nerve 0–30 days after transaction. In the most proximal nerve segment, all the measured proteins were transiently increased. In the proximal and distal stumps adjacent to the transection, the studied proteins were decreased indicating degeneration of the nerve. Within the silicone chamber, the regenerating nerve expressed the Schwann cell S-100 protein already at 7 days, whereas the neurofilament polypeptides appeared later. These observations are corroborated by previous morphological studies. The biochemical method described provides a new and fast approach to the study of nerve regeneration.     

S-100 alpha-like immunoreactivity in tubules of rat kidney. A clue to the function of a "brain-specific" protein

The localization of the alpha and beta subunits of S-100 protein was studied in normal tissue where the identification of three subclasses of S-100 containing cells was derived: i) cells that contain both alpha and beta subunits; ii) cells that contain only the alpha subunit; and iii) cells that contain only the beta subunit. In this study monospecific antibodies against the S-100 alpha and beta subunits were used to characterize the S-100-like immunoreactivity in the rat kidney: Certain cells in the distal nephron, i.e., the connecting piece, collecting ducts, and the thin limb of Henle's loop, contained S-100 alpha immunoreactivity. Proximal tubules, the thick ascending limb of Henle's loop, the distal tubules, and the juxtaglomerular apparatus were negative. No S-100 beta immunoreactivity was found in kidney tubules. However, Schwann cells of renal pelvic nerves contained S-100 beta immunoreactivity. The presence of S-100 alpha antigen in certain cells of the kidney gives further support to the assumption that the alpha subunit of S-100a is related to cells that are highly involved in pH, electrolyte, and water regulation.     

PURIFICATION OF SOLUBLE GLYCOPROTEINS FROM HUMAN NERVOUS TISSUE AND LIVER

—The isolation of some water-soluble, 50% methanol-soluble glycoproteins from human normal brain, human ependymoma and human liver is reported. One of them (AM protein) has a similar, or even identical, electrophoretic mobility to brain-specific protein S-100 under certain electrophoretic conditions. Although bands of identical mobility are found in both brain and liver samples, we lack experimental evidence, at the present stage of this work, to draw conclusions on the identity (or relatedness) of such proteins. On the other hand, the brain-soluble glycoproteins appear to be antigenically different from brain protein S-100, from brain α₂-glycoprotein and from GP 350 glycoprotein.