Showing papers on "Respiratory epithelium published in 1985"

Damage of the airway epithelium and bronchial reactivity in patients with asthma.

Abstract: We measured bronchial reactivity to inhaled histamine and prepared electron micrographs from bronchial biopsies from 8 asthmatic patients who never smoked (2 females, 6 males, 18 to 62 yr of age). Judging from their clinical histories and the need for medication and long-term follow-up of PEF values, 2 of them had mild asthma, 3 moderately severe, and 3 severe asthma. They had not experienced respiratory infections for at least 2 months prior to the study. The result, obtained from the cumulative dose-response curve, was expressed as the provocative dose (PD20) of histamine producing a 20% fall in forced expiratory volume in one second (FEV1). In 5 patients, the PD20 varied from 0.049 mg to 2.234 mg. In the sixth patient, only PD15 could be measured (5.187 mg). In 2 patients, the low initial FEV1 values, because of severe, partly irreversible obstruction, prevented the measurement of bronchial reactivity. Bronchial biopsies were taken with rigid tube bronchoscopy from 3 levels: (1) at the carina of the right upper lobe, (2) at the opening of the right middle or lower lobe, and (3) inside the right lower lobe. The specimens were prepared for both light and electron microscopy. Fresh biopsies showed that asthma patients can have epithelial destruction at all levels of the airways. The ciliated cells appeared to be the most destroyed cell type in the epithelium. Intraepithelial nerves and mast cells were seen. Epithelial destruction in the respiratory tract of the asthma patients with mild to severe bronchial hyperresponsiveness was prominent enough to expose the epithelial nerves for specific or nonspecific stimuli.

Respiratory epithelium inhibits bronchial smooth muscle tone

Abstract: The aim of the present study was to determine whether or not the respiratory epithelium can modulate the responsiveness of bronchial smooth muscle. Paired rings of canine bronchi (4–6 mm OD), in so...

The effect of airway epithelium on smooth muscle contractility in bovine trachea.

Abstract: In bovine tracheal smooth muscle the presence of airway epithelium significantly reduced the sensitivity and maximum contractile response to histamine, 5-hydroxytryptamine (5-HT) or acetylcholine. Muscle contraction induced by K+ and electrical field stimulation was of similar magnitude both in the presence or absence of adherent epithelium. The effect of epithelium on smooth muscle contractility was unaffected by pretreatment with indomethacin (10(-6) M) or mepacrine (5 X 10(-5) M). The relaxant response to isoprenaline was enhanced in the presence of epithelium, although this was significant only in the case of precontraction with 5-HT. It is concluded that the bronchial epithelium may produce a relaxant factor which is not a cyclooxygenase or lipoxygenase product. The production of this factor may be reduced or lost following epithelial damage and this may be important in the pathogenesis of bronchial hyperresponsiveness in asthma.

Lung Cell Biology

Abstract: The sections in this article are: 1 Basic Plan of the Cell 1.1 Cell Nucleus 1.2 Cytoplasmic Membrane Systems and Granules 1.3 Mitochondria 1.4 Ground Substance and Cytoskeleton 1.5 Plasma Membrane 2 Organization of Lung Cell Population 2.1 Histogenetic Origin of Lung Cells and Tissues 2.2 Differentiation of Functional Zones 2.3 Morphometry of Lung Cell Population 3 Epithelium 3.1 Epithelium of Conducting Airways 3.2 Alveolar Epithelium 4 Vascular Endothelium 4.1 Structure of Capillary Endothelium 4.2 Structure of Arterial and Venous Endothelium 4.3 Metabolic Functions of Endothelial Cells 5 Interstitial Cells 5.1 Cells Related to Connective Tissue Fibers 5.2 Interstitial Cells With Contractile Properties 5.3 Lymphatics and Free Cells 5.4 Nerves 6 Cells of Pulmonary Defense System 6.1 Alveolar and Interstitial Macrophages 6.2 Cells of Immune Defense System 6.3 Granulocytes 7 Mesothelial Cells of Pleura

Genesis of cilia and microvilli of rat nasal epithelia during pre-natal development. I: Olfactory epithelium, qualitative studies

Abstract: Rat foetuses from intra-uterine days E13 through E22 (day before parturition) and adults were used for a qualitative electron-microscopic investigation of the development of ciliated/microvillous surfaces of the olfactory epithelium. In the E13 and most of the E14 embryos the epithelial surface is not yet characteristically olfactory. Apical cell profiles show primary cilia. These can arise at the epithelial surface or below. From E14 onwards the epithelial surface acquires olfactory characteristics. Dendritic endings of the olfactory receptor cells can be found amidst microvillous profiles of supporting cells. Either cell type may bear primary cilia. From E16 onwards the receptor cells sprout multiple olfactory cilia, but cells with primary cilia are found throughout pre-natal development. These primary cilia are, at least for a while, retained during the formation of the secondary cilia. Primary cilia always have distinct necklaces at their base. Otherwise, especially with respect to their tips, their morphology can vary. Originally they have expanded tips (up to E14); later on such wide tips are no longer encountered (E16 and E17). Primary cilia of receptor cells never have wide tips. Appreciable numbers of endings with tapering olfactory cilia are discerned around E18 and especially E19. Throughout pre-natal development posterior/superior parts of the septal olfactory epithelium are more precocious than anterior/inferior parts, in particular in the region of transition with the respiratory epithelium. This advance in development includes total densities of dendritic endings of olfactory receptor cells, densities of multiciliated endings alone and lengths of supporting cell microvilli. This difference is discussed with respect to the topography of the olfactory epithelial surface in adult animals. In addition to the systematic topographic variation, a number of more local, apparently not-systematically distributed, topographic variations present during development are described. Most of these also occur in adult animals and they include heterogeneity in length of supporting cell microvilli and the presence of patches of supporting cells with rounded apical protuberances, of patches displaying dendrites with polyaxonemes rather than individual cilia and of scattered atypical cells (neither typical olfactory receptor nor olfactory supporting cells). At their surfaces such atypical cells can resemble inner-ear hair cells. Relative to olfactory receptor and supporting cells there are only very few atypical cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Mesenchymal control of branching pattern in the fetal mouse lung.

Abstract: The effect of mesenchyme on specialization of respiratory epithelium in the fetal mouse was tested in organ cultures. Heterologous combinations were made between respiratory and non-respiratory lung epithelia and the corresponding mesenchymes. Isolated terminal respiratory buds of fetal mouse lungs were recombined with mesenchyme from chick lung parabronchi, mouse trachea or from the avascular, non-respiratory air sacs of chick lungs. Isolated non-branching chick air sacs were combined with mouse terminal bud mesenchyme or mesenchyme from the respiratory branches of chick lungs. Air sac epithelia branched in a pattern characteristic of the chick lung when combined with chick respiratory mesenchyme and in a pattern characteristic of mouse lung when combined with mouse terminal bud mesenchyme. Mouse terminal bud epithelia did not branch with either mouse tracheal mesenchyme or chick air sac mesenchyme but branched in a chick pattern with chick parabronchial mesenchyme. Electron microscopic examination of the cultures showed that all chick air sac epithelial cultures failed to produce surfactant (lamellar bodies) even when they branched. Control cultures of mouse terminal buds contained large numbers of lamellar bodies; mesenchyme which suppressed branching reduced the number of lamellar bodies to only a few in a small proportion of the cells. Culture medium supplemented with growth factors and hormones increased the number of lamellar bodies in heterologous mouse combinations but did not bring the number to control levels. Supplemented medium had no effect on lamellar body production by chick air sac epithelium. The results indicate that branching pattern is determined by the mesenchyme surrounding the epithelial primordium. However, the capacity to synthesize surfactant is determined by the source of the epithelium; mesenchyme may control the degree of expression but not the absolute presence or absence of the differentiated condition.

Neuroendocrine cells in the developing human lung: morphologic and functional considerations.

Abstract: The structure, distribution, and frequency of neuroendocrine (NE) cells in human fetal lung from early stages of development to term are described. Neuroendocrine cells were studied by electron microscopy and immunostaining for serotonin and bombesin, recently identified markers of these cells in human lung. The differentiation of NE cells within the airway epithelium proceeded centrifugally and followed the development of the bronchial tree. The first NE cells, identified at 8 weeks' gestation, appeared well-differentiated compared with adjacent epithelial cells, and were immunoreactive for serotonin. The first bombesin-immunoreactive cells were detected at 10 weeks' gestation. Fetal lungs from midgestation contained several ultrastructurally distinct NE cell types, distributed singly and in groups. Serotonin-immunoreactive cells were more frequent during early stages of development and were predominantly located in larger airways. Bombesin-immunoreactive cells became more numerous towards term and were concentrated in small peripheral airways. The well-differentiated appearance and large number of NE cells in fetal lung, and their increase in number towards term, suggest an important role for these cells during intrauterine life and neonatal adaptation. Whether this role involves neurohormonal regulation of fetal-neonatal pulmonary circulation or local (paracrine) or endocrine function requires further investigation.

An immunohistochemical characterization of rhesus monkey respiratory secretions using monoclonal antibodies.

Abstract: A series of 12 monoclonal antibodies was made against mucous and serous components of rhesus monkey trachea. These antibodies were used to localize secretory products in the respiratory epithelium by immunohistochemical methods. Mucous cells of the tracheal surface epithelium and submucosal glands were shown by histochemical methods to be a homogeneous population containing periodate-reactive sulfated glycoconjugates. Immunohistochemical staining using the monoclonal antibodies on glycol methacrylate sections serial to those stained histochemically revealed a more antigenically heterogeneous population of secretory cells. Four distinct staining patterns were observed with the 12 monoclonal antibodies. Eight antibodies reacted with most, but not all, mucous and serous cells. Two antibodies recognized subpopulations of secretory cells. One antibody stained tracheal mucous cells with a concentration of reaction product on the luminal border, and one antibody stained only serous cells within the glands. Ten o...

Pattern of distribution of T lymphocytes, Langerhans cells and HLA-DR bearing cells in normal human oral mucosa

Abstract: – The tissue distribution of helper/inducer and suppressor/cytotoxic T cells, Langerhans cells (LC) and HLA-DR bearing cells was determined in normal oral mucosa by use of monoclonal antibodies OKT4, OKT8, OK.T6 and OKIal, respectively. OKT4+ and OKT8+ cells were invariably present in normal oral epithelium and in the lamina propria. OKT8+ cells were consistently seen inside the basal cell layer of the epithelium. The distribution of LC in oral epithelium showed regional variation. In palatal epithelium LC were evenly distributed in the basal half of the epithelium, whereas in buccal mucosa the highest concentration of LC was seen in the epithelium overlying the tips of connective tissue papillae. OKIal stained dendritic cells in the epithelium and plump cells with small dendritic processes in the connective tissue. Some of the latter were located close to the basal cells of the epithelium. The consistent relationship between immunocompetent cells and the epithelium of the oral mucosa suggests the presence of a local immunologic defence barrier in the oral mucosa.

Fine structure of the epithelia of the vomeronasal organ of horse and cattle. A comparative study.

Abstract: The vomeronasal organ of both horses and cattle is a tubular structure situated bilaterally at the base of the nasal septum. In frontal plane the shape of its lumen is semilunar to crescent. The sensory epithelium lining the medial wall of the lumen contains receptor, supporting and basal cells with some surface modifications in both species. In the horse, a structure similar to a microprocess was observed among the microvilli of receptor cells. In cattle, a large mass of the cytoplasm of the receptor cell occasionally protrudes to form a bleb-like structure. The supranuclear cytoplasm of the receptor cells contain mitochondria, free ribosomes, rough endoplasmic reticula, Golgi apparatus, lysosomes and multivesicular bodies. Some receptor cells were pyknotic. In both species the respiratory epithelia of the lateral wall of the lumen contain ciliated, non-ciliated and basal cells. In the horse, this epithelium differs from that of other species in evidence of prominent secretory function.

Ultrastructure of the bronchial epithelium in three children with asthma.

Abstract: The ultrastructure of the bronchial epithelium of three asthmatic girls was studied from material obtained during bronchoscopy. In all patients the large bronchi were lined with an altered pseudostratified ciliated epithelium having a severely damaged ciliary border. Injury to the ciliated cells was manifested by apical bleb formation, destruction of free kinocilia, pathological ciliogenesis, dilation of the spaces of the endoplasmic reticulum and Golgi complex, an increase in the number of vacuoles and lysosomes, and the appearance of altered mitochondria. The most outstanding feature of the epithelium was the marked hyperplasia of the goblet cells with the development of intraepithelial mucous glands. The mucous elements of the epithelium had discharged their mucus. Further, there were signs of mucus cell injury and degeneration. Squamous metaplasia of the pseudostratified epithelium was not observed.

Experimental bovine respiratory syncytial virus infection in conventional calves: ultrastructural respiratory lesions.

Abstract: The morphogenesis and repair of airway and alveolar injury induced by bovine respiratory syncytial virus (BRSV) was studied ultrastructurally in conventional calves to characterize pulmonary cell types susceptible to viral infection and cytopathologic changes associated with infection. Viral nucleocapsids and budding virions were present in tracheal and bronchial ciliated and nonciliated epithelial cells and mucous cells 3, 5, and 7 days after inoculation and in bronchiolar ciliated and nonciliated epithelial cells 5 days after inoculation. Mild interstitial pneumonia was observed 5 days after inoculation and was characterized by swelling of type 1 and type 2 alveolar epithelial cells, interstitial edema, and infiltration by lymphocytes and macrophages. Viral assembly and release in tracheal and bronchial epithelial cells was associated with loss of cilia from ciliated cells, formation of syncytial epithelial cells, swelling of mitochondria and endoplasmic reticulum, and cell necrosis. Neutrophils, lymphocytes, and macrophages were present in close association with the viral-infected and damaged epithelial cells. There was intercurrent hyperplasia of basal epithelial cells that, in association with other epithelial lesions, resulted in the loss of normal ciliated epithelium in these airways 5 and 7 days after inoculation. Regeneration of airway epithelium was largely completed by 10 days after inoculation, except in 1 of 4 calves that had failure of epithelial repair and that developed secondary bacterial pneumonia. Pulmonary ultrastructure in BRSV-inoculated calves 30 days after inoculation was indistinguishable from that in controls. The results demonstrated that BRSV can induce reversible alterations in airway epithelium, which may cause depression of mucociliary clearance and thereby enhance susceptibility to bacterial infection.

Bordetella pertussis tracheal cytotoxin.

Abstract: The most consistent pathological feature of pertussis is the selective colonization and subsequent destruction of ciliated cells in the respiratory epithelium. Phase I B. pertussis can reproduce the human respiratory tract cytopathology during in vitro infection of hamster tracheal organ cultures. However, most isolated biologically active components produced by B. pertussis (lymphocytosis-promoting factor, adenylate cyclase, dermonecrotic toxin, etc.) have no apparent cytopathic effect on the respiratory epithelium. We have purified a glycopeptide from the culture supernatant of virulent B. pertussis that mimics completely the ciliated cell pathology characteristic of pertussis (5). Tracheal cytotoxin (TCT) is released during log phase broth culture and consists of 15 amino acid residues as well as two amino sugars. The selective biological activity of TCT has been studied in tracheal organ cultures by light and electron microscopy. A series of pathological changes precedes the eventual extrusion of ciliated cells, while all other epithelial cell types appear ultrastructurally normal. TCT also causes a dose-dependent inhibition of DNA synthesis in cultured hamster trachea epithelial cells, providing a quantitative bioassay to monitor TCT activity during purification steps. Previously, TCT could be completely purified from oxidized glutathione (a major contaminant from the culture medium) only by high-voltage paper electrophoresis, a procedure not well suited for large scale work. We have now substituted a final column chromatography step that separates TCT from oxidized glutathione and other contaminating peptides. This change and other preparative scale adaptations now allow us to purify 150-250 nmol of biologically active TCT from one liter of culture supernatant (3-4 X 10(13) bacteria), a ten-fold increase over our previous batch size with no increase in processing time.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of differentiation of tracheal epithelial cells by retinoids.

Abstract: An in vitro culture system of rabbit tracheal epithelial cells has been developed to study the regulation of differentiation of the respiratory epithelium on the molecular level. At high density in the absence of retinoids these cells become squamous, stratify, and ultimately form cross-linked envelopes. Several factors influence this terminal differentiation: high Ca2+ concentrations and serum factors promote, whereas retinoids and medium conditioned by fibroblasts inhibit this process. Terminal squamous cell differentiation is accompanied by several biochemical changes: the synthesis of proteoglycans is dramatically reduced and the expression of keratin intermediate filaments is altered. Besides the eight major keratins expressed in undifferentiated cells, terminally differentiated cells also express a 48 kDa keratin. The expression of this keratin correlates well with squamous cell differentiation and appears to be under the control of retinoic acid. The level at which these biochemical changes are regulated has yet to be established. Specific retinol- and retinoic acid-binding proteins have been identified in these cells; the correlation between binding and biological activity of retinoids in this system is in agreement with a role for these binding proteins in mediating the action of these agents.

Ultrastructural characterization of epithelial cell membranes in normal human conducting airway epithelium: A freeze‐fracture study

Abstract: Cell membranes of normal human nasal and tracheal epithelium were characterized by means of freeze-fracture preparations. These investigations illustrated a predictable variability in the distribution of membrane-associated particles on PF-faces of different cell types and in different regions of the same cell. Details of the fine structure and variability of tight junctional complexes in different cell types are presented as are ultrastructural perspectives of cell membrane involvement in ciliogenesis and in mucus secretion. Because ciliogenic profiles and nascent tight junctional complexes were observed more frequently in nasal epithelial cells, these features provided markers of cellular differentiation. Based on the frequent appearance of such indicators, these observations suggested that cell turnover may be more rapid in the region of the nasal turbinates than in the trachea. There was no appreciable evidence of ultrastructural variability between the epithelial cell membranes of similar cell types in the upper and lower respiratory tract.

Junctions of squamous epithelium with middle ear mucosa.

Abstract: Specimens obtained from the middle ear during surgery for cholesteatoma showed either abrupt junctions without metaplasia or junctions of varying width with metaplastic epithelium. Another form of junctional area showed pronounced inflammatory cell reaction with squamous epithelium projections growing into the stroma under the columnar epithelium. Immunofluorescent staining for cytokeratins showed distinct decoration of the columnar and metaplastic epithelia as well as of the basal cells of squamous epithelium. Prekeratin staining showed decoration of both squamous and metaplastic epithelium and no staining of the columnar epithelium. The findings suggest that metaplasia forms part of the migrating front of the squamous epithelium and alone plays no major role in cholesteatoma genesis.

Vitamin A deficiency and sensory function.

Abstract: Morphological investigation of tongue, olfactory epithelia, trachea and inner ear in vitamin A deficiency are reported. The results support assumptions concerning the loss of sensory function as been at least a secondary effect of alterations of the neighbourhood of the sensory cells caused by vitamin A deficiency. Taste buds are hindered in function by a dense layer of squamous cells and olfaction is decreased by atrophy of the surrounding respiratory epithelium. Inner ear functionality seems to be affected by vitamin A status via a stabilizing effect on the endolymph-perilymph barrier.

Glass fibers and vapor phase components of cigarette smoke as cofactors in experimental respiratory tract carcinogenesis.

Abstract: Syrian golden hamsters were given intratracheal instillations of glass fibers with or without BP suspended in saline, once a fortnight for 52 weeks; the experiment was terminated at week 85. No tumors of the respiratory tract were observed in hamsters treated with glass fibers alone. There was no indication that glass fibers enhanced the development of respiratory tract tumors induced by BP. In another study Syrian golden hamsters were exposed to fresh air or to a mixture of 4 major vapor phase components of cigarette smoke, viz. isoprene (800----700 ppm), methyl chloride (1000----900 ppm), methyl nitrite (200----190 ppm) and acetaldehyde (1400----1200 ppm) for a period of at most 23 months. Some of the animals were also given repeated intratracheal instillations of BP or norharman in saline. Laryngeal tumors were found in 7/31 male and 6/32 female hamsters exposed only to the vapor mixture, whereas no laryngeal tumors occurred in controls. The tumor response of the larynx most probably has to be ascribed entirely to the action of acetaldehyde. Simultaneous treatment with norharman or BP did not affect the tumor response of the larynx. Acetaldehyde may occur in the vapor phase of cigarette smoke at levels up to 2000 ppm. Chronicmore » inhalation exposure of rats to acetaldehyde at levels of 0 (controls), 750, 1500 or 3000----1000 ppm resulted in a high incidence of nasal carcinomas, both squamous cell carcinomas of the respiratory epithelium and adenocarcinomas of the olfactory epithelium. It was discussed that acetaldehyde may significantly contribute to the induction of bronchogenic cancer by cigarette smoke in man.« less

Orthogonal arrays in normal and injured respiratory airway epithelium.

Abstract: Orthogonal arrays are found on plasma membranes of glial cells, in the central nervous system, on muscle plasma membranes at neuromuscular junctions, and on a variety of epithelial cells. These structures have been correlated with ion flux. With the aid of freeze fracture technique, orthogonal particle arrays were found on plasma membranes on airway epithelial cells of rats and hamsters. They have been found in abundance at the base of secretory cells throughout normal airway epithelium. These structures were found to increase in number during regeneration in response to injury and they were found in great numbers on plasma membranes of all airway cells in response to acute and chronic NO2 exposure. The lateral and basal plasma membranes of the respiratory epithelium are a new source for studying orthogonal arrays. The normal number and distribution of these arrays can be perturbed in response to mechanical and chemical injury.

A cystic teratoma in skin.

Abstract: This is a report of a child who had a subcutaneous cyst that was filled with cornified cells and hair and lined by respiratory epithelium with seromucous glands and partly by squamous epithelium like that of the follicular infundibulum to which epithelial structures of adnexa were attached The cyst wall was encircled incompletely by fascicles of mature smooth muscle Differential diagnosis is discussed and cystic teratoma in skin is suggested as a proper term for the condition

Orthogonal Arrays in Normal and Respiratory Airway Epithelium Injured

Abstract: Orthogonal arrays are found on plasma membranes of glial cells, in the central nervous system, on muscle plasma membranes at neuromuscular junctions, and on a variety of epithelial cells These structures have been correlated with ion flux With the aid of freeze fracture technique, orthogonal particle arrays were found on plasma membranes on airway epithelial cells of rats and hamsters They have been found in abundance at the base of secretory cells throughout normal airway epithelium These structures were found to increase in number during regeneration in response to injury and they were found in great numbers on plasma membranes of all airway cells in response to acute and chronic NO2 exposure The lateral and basal plasma membranes of the respiratory epithelium are a new source for studying orthogonal arrays The normal number and distribution of these arrays can be perturbed in response to mechanical and chemical injury Orthogonal particle assemblies (rectangular arrays) are closely packed 6-nm intramembrane particles arranged in a square lattice These assemblies have been found on the P-face of freeze-fractured plasma membranes of a variety of cells (1- 11) Mammalian astrocytes, in particular, can be identified in freeze fractures by the abundance of these structures on their plasma membrane (12) The biochemical nature of these particles and their function in the membrane have not been determined It has been speculated that these structures are associated with ion flux, at least in astrocytes (13) In this report we describe a rich source for these orthogonal structures in respiratory epithelium of rats and hamsters We also describe conditions that increase their abundance, thereby perhaps providing a mechanism whereby these struc- tures could be biochemically characterized and their function determined

Histology and ultrastructure of the human esophageal epithelium. I. Normal and parakeratotic epithelium.

Abstract: The authors present a histological and ultrastructural analysis of normal and parakeratotic human esophageal epithelium. Parakeratosis is encountered frequently during routine examinations of noncancerous esophageal mucosa in patients with carcinoma of the esophagus. Morphologically, this alteration corresponds to an incomplete keratinization of the esophageal epithelium with an excessive accumulation of keratin microfilaments, nuclear maturation reaching the stages of pyknosis and lysis, and anomalies in surface cell desquamation.