In general, the nasal cavity of turtles is divided into two chambers: the upper chamber, lined with the olfactory epithelium containing ciliated olfactory receptor cells, and the lower chamber, lined with the vomeronasal epithelium containing microvillous receptor cells. In the nasal cavity of soft-shelled turtles, however, differences between the upper and lower chamber epithelia are unclear d...

Eukaryotic cells discharge secretory products by fusion of secretory vesicles with the plasma membrane, a process that is often regulated. In neurons and endocrine cells, exocytosis uses intracellular Ca as the final trigger and can be enhanced in different ways by protein kinases. Thus, in pituitary gonadotropes, protein kinase C (PKC) increases the Ca sensitivity of exocytosis (Zhu et al., 20...

Evidence for recovery of surface membrane and its fusion with Golgi cisternae has been obtained previously in several glandular cells. This study was conducted to determine whether or not membrane is similarly retrieved from the surfaces of plasma cells from lymph nodes (of rats immunized with horseradish peroxidase [HRP]) and mouse myeloma cells (RPC 5.4 and X63 Ag 8 cell lines). Electron-dens...

The secretory vesicles of human neutrophils are rapidly mobilizable vesicles that contain several GPI-linked proteins, a characteristic feature of caveolae in other cells. To investigate whether secretory vesicles are structurally related to caveolae, we examined human neutrophils for the presence of caveolin, a major constituent of caveolae, by immunoblotting using monoclonal and polyclonal an...

Cystic fibrosis (CF) is caused by mutations in the gene coding for the CF transmembrane conductance regulator (CFTR). From human normal tracheal submucosal gland cells in culture, we identified endogenous CFTR as a 170 kDa protein, consistent with that of fully glycosylated, mature CFTR molecule. This observation led to the hypothesis that airway secretory glands could be an important site for ...

BACKGROUND Mucociliary transport (MCT) is a defense mechanism of the airway. To study the underlying mechanisms of MCT, we have both developed an experimental model of cultures, from human adenoid tissue of ciliated and secretory cells, and characterized the response to local chemical signals that control ciliary activity and the secretion of respiratory mucins in vitro. MATERIALS AND METHODS...

The mouse pituitary cell line, AtT-20, packages the adrenocorticotropic hormone (ACTH) in secretory vesicles and releases it when the cell is stimulated with secretagogues. These cells have the capacity, after transfection with the appropriate DNA, to package heterologous peptide hormones into the regulated secretory vesicles (Moore, H. P. H., M. D. Walker, F. Lee, and R. B. Kelly, 1983, Cell, ...

Chromogranin B (CgB, secretogranin I) is a secretory granule matrix protein expressed in a wide variety of endocrine cells and neurons. Here we generated transgenic mice expressing CgB under the control of the human cytomegalovirus promoter. Northern and immunoblot analyses, in situ hybridization and immunocytochemistry revealed that the exocrine pancreas was the tissue with the highest level o...

PURPOSE To calculate the hit probabilities by alpha-particles emitted by radon progeny for basal and secretory cell nuclei in the epithelium of the human tracheobronchial tree. MATERIALS AND METHODS The equilibrium activities on the surface of airway tubes were calculated using the ICRP66 model. The stopping-power and ranges of alpha-particles in tissue were adopted from ICRU49. A semi-analyt...