Ultrastructural localization of epidermal growth factor receptor in human parotid gland.

The epidermal growth factor receptor (EGFR) is widely distributed in several organs in which, following interaction with its ligand, it can affect development and differentiation. The aim of this study was to define the distribution of EGFR in human parotid gland by means of a post-embedding immunogold staining method. Normal human parotid glands obtained at surgery were routinely prepared for electron microscopy. Semithin and ultrathin sections were treated for immunocytochemistry using a mouse monoclonal antibody specific for EGFR and a goat anti-mouse gold conjugated secondary antiserum. At the light microscope level, EGFR reactivity was revealed by a specific dark staining in both acinar and ductal cells. At the electron microscope level, EGFR was strongly stained in the cytoplasmic compartments and occasionally labeled on cell surfaces. In acinar cells, it appeared to be associated with small vesicles of uncertain nature that were scattered among the secretory granules. EGFR-positive vesicles were also observed in the ductal cells, with the most intense labeling being localized in striated ducts. Since cytoplasmic vesicles were previously found to be EGF-positive, these results may be due to the presence of the EGF-EGFR complex that is internalized after binding of EGF to the surface EGFR.

Algebra: solucionario de A.Baldor

Contenido:1.Suma 2.Resta 3.Signos de agrupacion 4.Multiplicacion 5.Division 6.Productos y cocientes notables 7.Teorema del residuo 8.Ecuaciones enteras de primer grado con una incognita 9.Problemas sobre ecuaciones enteras de primer grado con una incognita 10.Descomposicion factorial 11.Maximo comun divisor 12.Minimo comun multiplo 13.Fracciones algebraicas.Reduccion de fracciones 14.Operaciones con fracciones algebraicas 15.Ecuaciones numericas fraccionarias d eprimer grado con una incognita 16.Ecuaciones literales de primer grado con una incognita 17.Problemas sobre ecuaciones fraccionarias de primer grado 18.Formulas 19.Desigualdades.Inecuaciones 20.Funciones.