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Biomedical subjects

R D Dey

Publications and source records attributed to R D Dey.

45 records · Page 3Linked to original sources
PubMed1986

Characterization of human pulmonary endocrine cells maintained in vitro.

Endocrine cells located in the epithelium of human fetal airways contain the amine, 5-hydroxytryptamine (5HT), and the peptide, bombesin (BOM), but difficulties in studying these cells experimentally have slowed progress in understanding their functional roles. This investigation describes an in vitro method to maintain pulmonary neuroendocrine cells (PNEC) in organ culture. Bronchial trees from human fetal lungs were dissected free of adherent blood vessels and lung tissue. Explants of the airways were placed in culture dishes containing defined tissue culture medium for five days. Using indirect immunofluorescence, 5HT- and BOM-like immunoreactive cells were observed both in nonincubated airways and in explants maintained for five days in organ culture. The number of 5HT-immunoreactive cells/0.1 mm2 of airway epithelium was not significantly different in the two groups, although there was a significant reduction in 5HT content measured by HPLC after the five-day culture period. The diameter of dense core vesicles and the number of dense core vesicles/micron2 of endocrine cell cytoplasm in cultures were not significantly different from non-incubated controls. Treatment of the explants with the 5HT-synthesis inhibitor p-chlorophenylalanine resulted in a significant reduction both in the number of 5HT-containing cells/0.1 mm2 of airway epithelium and in the 5HT content. These results demonstrate that both 5HT and BOM content in endocrine cells of explants from human fetal airways can be well maintained in organ culture for at least 5 days and that they are responsive to pharmacologic inhibition of 5HT synthesis.

Bombesin↗
PubMed1985

Deficient vasoactive intestinal peptide innervation in the sweat glands of cystic fibrosis patients.

The innervation of acini and ducts of eccrine sweat glands by immunoreactive, vasoactive intestinal peptide-containing nerve fibers was sharply reduced in seven patients with cystic fibrosis compared to eight normal subjects. The decrease in innervation by this neuropeptide, which has been shown to promote blood flow and the movement of water and chloride across epithelial surfaces in other systems, may be a basic mechanism for the decreased water content and relative impermeability of the epithelium to chloride and other ions that characterize cystic fibrosis.

Adolescent↗
PubMed1984

Ultrastructural immunocytochemical localization of 5-hydroxytryptamine in gastric enterochromaffin cells.

Enterochromaffin (EC) cells in the gastrointestinal tract are known to contain 5-hydroxytryptamine (5HT). The probable ultrastructural localization of 5HT in the dense core vesicles ( DCVs ) of EC cells is based on the use of histochemical techniques, such as argentaffinity and the potassium dichromate reaction. In the present paper we describe an immunocytochemical method for specifically localizing 5HT in EC cells by electron microscopy. Pieces of mucosa from the pyloric region of the rabbit stomach were prepared for electron microscopy by fixation in 0.5% glutaraldehyde-picric acid-formaldehyde without osmication , and then embedded in LX-112. Thick sections (1 micron) were mounted on glass slides and processed for the fluorescence immunocytochemical localization of 5HT. Thin sections (60-90 nm) were mounted on formvar-coated slot grids and processed for the ultrastructural immunocytochemical localization of 5HT. Both the thick and thin sections were processed by an identical procedure, beginning with a 30-min incubation in anti-5HT antiserum diluted 1:1400, followed by an IgG-FITC-gold-labeled second antibody. Fluorescent EC cells were consistently observed in the thick sections of gastric mucosa. By carefully trimming and sectioning the adjacent block face, the identical EC cell could be identified by electron microscopy. A quantitative analysis revealed the number of gold particles in EC cells to be significantly greater over the cores of DCVs than over the non-core cytoplasm or over the nucleus. Absorption of the primary antiserum with 5HT abolished all labeling, while absorption with a 5HT precursor, 5-hydroxytryptophan, did not significantly reduce core labeling. Non-EC epithelial cells were not labeled. These results demonstrate that immunoreactive 5HT in EC cells is stored in the cores of DCVs .

Animals↗
PubMed1983

Histochemical and ultrastructural characterization of serotonin-containing cells in rabbit tracheal epithelium.

Tracheal endocrine cells (TECs) that contain serotonin have been characterized previously by staining with ferric ferricyanide. In the present article, the ferric ferricyanide staining reaction has been used to locate the TECs in deplasticized thick sections of Epon-embedded rabbit tracheas. Adjacent thin sections of the same cell were subsequently observed by electron microscopy. The TECs were filled with dense-core vesicles (DCVs) located in the cytoplasm between the nucleus and the lumen and also lateral to the nucleus. In a separate experiment, pieces of rabbit trachea were treated with a solution of glutaraldehyde-dichromate to demonstrate the presence of amines. High levels of chromium were detected in the DCVs by energy-dispersive X-ray analysis. The results from these studies have correlated the ultrastructure of a serotonin-containing endocrine cell present in rabbit tracheal epithelium with a cell type previously characterized only by light and fluorescence histochemical methods. The results also indicate that serotonin in these cells is stored in the DCVs.

Animals↗
PubMed1981

Morphology, histochemistry, and distribution of serotonin-containing cells in tracheal epithelium of adult rabbit.

We have investigated morphologic and histochemical characteristics of serotonin-containing epithelial cells in tracheas from adult rabbits, using the Falck-Hillarp freeze-dried formaldehyde vapor technique. An intracellular formaldehyde-induced fluorescent substance was identified as serotonin by microspectrofluorometric techniques. Fluorescence microscopy and subsequent histochemical staining of the same sections demonstrated that serotonin-containing cells were argentaffin-, argyrophil-, and ferric ferricyanide-positive. The serotonin-containing epithelial cells were more numerous in ventral than in dorsal aspects of trachea. The number of detectable fluorescent cells was reduced after reserpine administration but was not affected by injecting the amine precursor L-dihydroxyphenylalanine (L-DOPA). The emission peak of the fluorophore was not significantly shifted after L-DOPA injections. The cells may regulate tracheobronchial-pulmonary function by releasing serotonin or other as yet unidentified biologically active substances.

Animals↗
PubMed1981

Localization of VIP-immunoreactive nerves in airways and pulmonary vessels of dogs, cat, and human subjects.

VIP-containing neurons were localized in lungs from dogs, cat, and human subjects by means of the indirect immunofluorescence technique. Nerve fibers and terminals were observed in the smooth muscle layer and glands of airways, and within the walls of pulmonary and bronchial vessels, especially at the medial-adventitial junction. VIP-positive nerve cell bodies were identified in ganglia located in the walls of bronchi. These findings provide an anatomic basis for the possible modulation of airway and pulmonary vascular function by this neuropeptide.

Animals↗