ABSTRACT
Olfactory receptor neurons are produced continuously in mammalian olfactory epithelium in vivo, but in explant cultures neurogenesis ceases abruptly. We show that in vitro neurogenesis is prolonged by fibroblast growth factors (FGFs), which act in two ways. FGFs increase the likelihood that immediate neuronal precursors (INPs) divide twice, rather than once, before generating neurons; this action requires exposure of INPs to FGFs by early G1. FGFs also cause a distinct subpopulation of explants to generate large numbers of neurons continually for at least several days. The data suggest that FGFs delay differentiation of a committed neuronal transit amplifying cell (the INP) and support proliferation or survival of a rare cell, possibly a stem cell, that acts as a progenitor to INPs.
Subject(s)
Fibroblast Growth Factors/pharmacology , Olfactory Receptor Neurons/cytology , Animals , Base Sequence , Cell Cycle/drug effects , Cell Division/drug effects , Cells, Cultured , DNA Primers/chemistry , In Vitro Techniques , Mice , Molecular Sequence Data , Olfactory Mucosa/cytology , Receptors, Fibroblast Growth Factor/metabolism , Recombinant Proteins , Stem Cells/cytologyABSTRACT
The purpose of this phenomenologic study was to describe effects of a parental critical care hospitalization on the family as viewed by children. Interviews were conducted with eleven male phenomenologic techniques and showed these four major themes: (1) emotional turmoil, (2) family disruption, (3) need for support, and (4) minor illnesses. These disruptions are strong and need to be treated through nursing interventions.
