Showing papers on "Respiratory epithelium published in 1991"

Adenovirus-mediated transfer of a recombinant alpha 1-antitrypsin gene to the lung epithelium in vivo

Abstract: The respiratory epithelium is a potential site for somatic gene therapy for the common hereditary disorders alpha 1-antitrypsin (alpha 1AT) deficiency and cystic fibrosis. A replication-deficient adenoviral vector (Ad-alpha 1AT) containing an adenovirus major late promoter and a recombinant human alpha 1AT gene was used to infect epithelial cells of the cotton rat respiratory tract in vitro and in vivo. Freshly isolated tracheobronchial epithelial cells infected with Ad-alpha 1AT contained human alpha 1AT messenger RNA transcripts and synthesized and secreted human alpha 1AT. After in vivo intratracheal administration of Ad-alpha 1AT to these rats, human alpha 1AT messenger RNA was observed in the respiratory epithelium, human alpha 1AT was synthesized and secreted by lung tissue, and human alpha 1AT was detected in the epithelial lining fluid for at least 1 week.

Regulation of transepithelial ion transport and intracellular calcium by extracellular ATP in human normal and cystic fibrosis airway epithelium

Abstract: 1 The role of extracellular nucleotides in regulation of ion transport activities (short circuit current, Isc) of human respiratory epithelia was studied. 2 Application of nucleotides to the apical or basolateral membrane of human nasal epithelium induced a concentration-dependent increase in Isc. 3 The rank order of potency of purine- or pyrimidine-induced changes in Isc of normal human nasal epithelium when applied to the apical membrane (UTP greater than or equal to ATP greater than ATP gamma S greater than 2MeSATP greater than ADP beta S much greater than beta gamma MeATP greater than or equal to alpha beta MeATP) or basolateral membrane (2MeSATP greater than UTP greater than ATP greater than ATP gamma S greater than alpha beta MeATP greater than beta gamma MeATP) is consistent with involvement of a P2 purinoceptor. A similar rank order of potencies was observed for nucleotide effects on intracellular calcium measured by Fura-2 fluorescence using microspectrofluorimetry. 4 Similar nucleotide potency in the regulation of ion transport and intracellular calcium in cystic fibrosis (CF) airway epithelium (UTP greater than or equal to ATP) was observed, suggesting purinoceptors might be used to stimulate ion transport processes that would promote hydration of airway secretions and facilitate their clearance from CF lungs. 5 These data provide evidence for the regulation of ion transport by P2 purinoceptors in normal and cystic fibrosis human airway epithelium.

Cytokine (tumor necrosis factor, IL-6, and IL-8) production by respiratory syncytial virus-infected human alveolar macrophages.

Abstract: Human alveolar macrophages (AM) are susceptible to infection with respiratory syncytial virus (RSV), but the infection is abortive after the initial cycles of virus replication. We have investigated if RSV infection of AM results in the production of cytokines TNF, IL-6, and IL-8, all of which may modulate inflammatory and immune responses to the virus, as well as may directly protect respiratory epithelial cells against spread of infection. Within 1 h after interaction with RSV, increased mRNA levels were found for all three cytokines. Peak expression of the mRNAs occurred at 3 to 6 h. The virus most effectively induced TNF mRNA expression greater than IL-6 mRNA greater than IL-8 mRNA, as compared to cytokine mRNA expression induced by bacterial endotoxin. Inactivated virus was almost as effective as live virus in inducing and maintaining increased IL-6 and IL-8 mRNA over 16 h, whereas live infectious RSV was necessary for maintaining TNF mRNA expression over the same time. Protein concentrations of the different cytokines in the supernatants of infected AM reflected the increased levels of mRNA in the cells. Despite the high levels of cytokines with possible antiviral activity (TNF and IL-6) in the AM supernatants, neither supernatants nor rTNF when added to bronchial epithelial cells protected them from infection with RSV. However, TNF, IL-1, and RSV, but not IL-6, induced IL-8 and IL-6 mRNA expression by the bronchial epithelial cells suggesting that cytokines produced by RSV-infected AM may be more important in modulating the inflammatory response in infection than directly interfering with virus infection/replication of airway epithelium.

Effects of human neutrophil elastase and Pseudomonas aeruginosa proteinases on human respiratory epithelium.

Abstract: It has been suggested that proteinase enzymes could play an important role in the pathogenesis of chronic bronchial infections including bronchiectasis and cystic fibrosis (CF). Because Pseudomonas aeruginosa frequently colonizes the respiratory tract in bronchiectasis and CF, we examined the in vitro effects of human neutrophil elastase (HNE) and proteinase enzymes produced by P. aeruginosa (elastase: PE; alkaline proteinase: PAP) on the ciliary beat frequency (CBF) and ultrastructure of human nasal ciliated respiratory epithelium. HNE (500 micrograms/ml) progressively reduced CBF and caused marked epithelial disruption; lower concentrations (100 and 20 micrograms/ml) also caused epithelial disruption but without slowing CBF. The effects of HNE (500 micrograms/ml) were completely abolished by adding alpha 1-antitrypsin (5 mg/ml). There was no synergy between HNE and pyocyanin, a product of P. aeruginosa which slows CBF. PE in phosphate-buffered saline also caused epithelial disruption without slowing CBF; however, PE in medium containing divalent metal ions caused CBF slowing as well as epithelial disruption at 100 micrograms/ml. PAP (500 micrograms/ml) had almost no effect on ciliated epithelium. The effects of HNE and PE on nasal and bronchial epithelium obtained from the same patient were similar. Light and transmission electron microscopy revealed that HNE and PE were cytotoxic and caused detachment of epithelial cells from neighboring cells and the basement membrane. There was cytoplasmic blebbing of the cell surface and mitochondrial damage; however, no increase of abnormalities in the ultrastructure of cilia on living cells was seen. These results support the hypothesis that HNE and PE contribute to the delayed mucociliary clearance and epithelial damage that is observed in patients with chronic bronchial infection.

Expression of the cystic fibrosis transmembrane conductance regulator gene in the respiratory tract of normal individuals and individuals with cystic fibrosis

Abstract: The most common mutation of the cystic fibrosis transmembrane conductance regulator gene, CFTR, associated with the clinical disorder cystic fibrosis (CF) is called "delta Phe508," a triple-base deletion resulting in loss of phenylalanine at residue 508 of the predicted 1480-amino acid CFTR protein. In the context that the lung is the major site of morbidity and mortality in CF, we evaluated airway epithelial cells for CFTR mRNA transcripts in normal individuals, normal-delta Phe508 heterozygotes, and delta Phe508 homozygotes to determine if the normal and delta Phe508 CFTR alleles are expressed in the respiratory epithelium, to what extent they are expressed, and whether there are relative differences in the expression of the normal and abnormal alleles at the mRNA level. Respiratory tract epithelial cells recovered by fiberoptic bronchoscopy with a cytology brush demonstrated CFTR mRNA transcripts with sequences appropriately reflecting the normal and delta Phe508 CFTR alleles of the various study groups. CFTR gene expression quantified by limited polymerase chain reaction amplification showed that in normal individuals, CFTR mRNA transcripts are expressed in nasal, tracheal, and bronchial epithelial cells at approximately 1-2 copies per cell, more than 100-fold greater than in pharyngeal epithelium. Importantly, allele-specific hybridization studies demonstrated that the normal and delta Phe508 CFTR alleles are expressed in the respiratory epithelium in similar amounts.

Anti-neutrophil elastase defense of the normal human respiratory epithelial surface provided by the secretory leukoprotease inhibitor.

Abstract: Secretory leukoprotease inhibitor (SLPI), a 12-kD nonglycosylated serine antiprotease with a high capacity for inhibiting neutrophil elastase (NE), is produced by cells of mucosal surfaces including the human lung. The molar concentrations of SLPI in total respiratory tract epithelial lining fluid (ELF) were 56 +/- 10% that of alpha 1-antitrypsin, suggesting SLPI may be more important for the anti-NE protection of the pulmonary epithelial surface than previously thought. However, evaluation demonstrated that SLPI in respiratory ELF was only one-third functional. Studies aerosolizing recombinant SLPI (rSLPI) to sheep demonstrated that in the short term, neither aerosolization and alveolar deposition nor the lavage procedure inactivated the SLPI molecule. In vitro studies with rSLPI demonstrated that exposure to oxidants did not modify the form of the molecule, while exposure to oxidants and NE caused the molecule to be cleaved from 12 to 8 kD. Consistent with this, evaluation of SLPI in lavage fluid of individuals with cystic fibrosis (a condition with oxidants and NE on the respiratory epithelium) showed that the SLPI was degraded. However, evaluation of SLPI in normal ELF by molecular sieve analysis and Western analysis demonstrated an intact 12-kD molecule, suggesting that the partial inactivation of SLPI in normals in vivo is not because it is complexed to NE or exposed to oxidants + NE. Together, these observations demonstrate that SLPI is present in large amounts in respiratory ELF, but since the majority of the SLPI is inactive, it likely does not play a significant role in protecting the normal respiratory epithelium, except perhaps in the upper airways where the levels of SLPI are the highest.

Interaction of Nontypable Haemophilus influenzae with Human Respiratory Mucosa In Vitro

Abstract: One laboratory strain (SH9) (n = 12) and five clinical isolates of unencapsulated Haemophilus influenzae replicated from 10(4) to 10(8) cfu/ml over 24 h in an organ culture of human respiratory mucosa in which only the intact mucosal surface is exposed. By transmission electron microscopy (TEM), bacteria were not seen in association with normal respiratory epithelium, even after incubation for 24 h. Histology and TEM morphometry demonstrated patchy and occasionally confluent damage to epithelia at this time, with bacteria associated only with cells that were structurally damaged. Scanning electron microscopy revealed an increased quantity of mucus in infected preparations; H. influenzae were associated with mucus by 14 h of incubation and with damaged epithelial cells by 24 h. Fimbriation of H. influenzae increased buccal cell adherence but did not facilitate association with normal respiratory epithelium and failed to increase epithelial damage or association with damaged cells. Epithelial damage may be prerequisite for association of H. influenzae with respiratory epithelium in vitro.

Wound repair of human surface respiratory epithelium.

Abstract: Surface airway epithelium is frequently injured by noxious inhaled agents, epithelial wound repair may be an important process by which the epithelial barrier integrity is maintained To evaluate the role of surface airway cells in the wound repair process, we developed an in vitro wounding model of human nasal epithelial respiratory cells in primary culture Circular wounds were made in the epithelial cell culture by detaching, with a glass capillary, approximately 50 cells from the collagen matrix Video microscopy and electron microscopy observations demonstrated the contribution of two main events during the repair process: the spreading of the cells at the edge of the wounded surface, and the migration of epithelial cell sheets Complete wound closure occurred within 5 to 8 h The inhibition of wound repair by cytoskeleton inhibitors or cellular protein synthesis inhibitors suggested that these factors are involved in the wound repair process of surface airway epithelium

Augmentation of Functional Prostaglandin E Levels on the Respiratory Epithelial Surface by Aerosol Administration of Prostaglandin E

Abstract: Prostaglandin E (PGE), a cyclooxygenase metabolite normally present in high concentrations in respiratory epithelial lining fluid (ELF), is capable of suppressing mesenchymal cell proliferation mediated by polypeptide-derived growth factors. Although PGE is normally abundant in respiratory ELF, PGE levels in ELF of individuals with idiopathic pulmonary fibrosis (IPF), a fibrotic lung disorder characterized by intraalveolar mesenchymal cell accumulation and fibrosis, were found to be 50%lower than normal (p < 0.01): that is, a relative PGE “deficiency” in ELF may enhance intraalveolar mesenchymal cell proliferation in IPF. With this background, it is rational to consider augmenting PGE levels in ELF as a future therapy for IPF. Since systemic administration of PGE is associated with significant adverse effects, in vitro and experimental animal studies were carried out to evaluate whether aerosol PGE administration could augment ELF PGE levels. Greater than 50%of a solution of PGE1 could be placed in drople...

Epithelial ion transport in the fetal and perinatal lung

Abstract: The lung is a complex organ whose intrauterine development depends on many factors, one of which is a continuous secretion of large volumes of Cl(-)-enriched fluid by the pulmonary epithelium. At birth this fluid must be cleared, and it is now known that this process depends in large part on active Na+ transport by the pulmonary epithelium. Only recently has it been possible to culture some of the different lung epithelial cells so that it is possible to investigate the role of individual epithelial cell types, their individual cellular transport mechanisms, and how these are affected by developmental lung maturity.

Modulation of neurogenic inflammation by neutral endopeptidase.

Abstract: The enzyme neutral endopeptidase (NEP) is bound to the membranes of selected cells in the airways that have receptors for tachykinins. The location of the enzyme, along with its selectivity of substrates (tachykinins are a preferred substrate), allows the enzyme to cleave tachykinins that come close to the cell-surface receptors. By cleaving and thus inactivating tachykinins released during stimulation of the sensory nerves, NEP limits the degree of neurogenic inflammation. Neutral endopeptidase exists in the basal cells of the airway epithelium, nerves, smooth muscle, glands, blood vessels, and perhaps other cells. Thus, the enzyme modulates smooth muscle contraction, gland secretion, cough, vascular permeability, and neutrophil adhesion. Decreased NEP activity occurs with epithelial removal, during respiratory viral infections, and during exposure to irritants (e.g., cigarette smoke and toluene diisocyanate). Delivery of recombinant NEP (rNEP) by aerosol suppressed cough responses during neurogenic infl...

Immunocytochemical localization of arachidonate 15-lipoxygenase in erythrocytes, leukocytes, and airway cells.

Abstract: In reticulocytes, the enzyme 15-lipoxygenase (15-LO) is believed to contribute to cellular differentiation, and in leukocytes and airway cells 15-LO generates inflammatory mediators. The recent availability of antibodies to 15-LO now allows us to determine which specific cells contain the enzyme, to characterize its subcellular localization, and to determine its expression at the translational level. A polyclonal antibody to recombinant human reticulocyte 15-LO was used with a standard immunofluorescent technique. In rabbit red blood cells, fluorescence appeared during the course of anemia. Early reticulocytes did not fluoresce, but more mature reticulocytes showed increased fluorescent intensity. Late reticulocytes contained little fluorescence. Among human leukocytes, only eosinophils fluoresced. In human trachea, 15-LO immunofluorescence was localized to epithelial cells, and both basal and ciliated cells fluoresced. In all cells studied, fluorescence was localized to the cytoplasm and was variable in degree among cells in each preparation. We conclude that the 15-LO of airway cells and eosinophils is immunologically related to the reticulocyte 15-LO. Furthermore, the variable fluorescence among cells (e.g., in epithelium) and during development (e.g., reticulocytes) suggests a role of 15-LO in cell growth and development.

Radon dosimetry based on the depth distribution of nuclei in human and rat lungs.

Abstract: Calculation of the absorbed dose by different lung cells is necessary for predicting the critical cells that are subject to injury from inhaled Rn and other alpha-particle sources. The absorbed dose was determined for cells in the airways of human and rat lungs, based on airway epithelial thickness and on cell cytoplasm and nuclear volume density as a function of depth from the luminal surface of the airway epithelium. The thickness of the stratified columnar epithelium of human airways varied from 57.8 micron in bronchi to 9.8 microns in bronchioles. The cell populations of all bronchi in human lungs were comparable. The cell populations of trachea and intrapulmonary airways in rats, however, were significantly different. Basal cell populations in rat trachea and human bronchi were similar and formed a nearly continuous layer. In rat bronchi, basal cells were not present in significant numbers. Measurements of epithelial thickness and volume density were used to estimate the absorbed dose for an alpha-particle source (214Po or 218Po) distributed uniformly in the mucus with an equivalent activity of 1 dpm per cm2 of epithelial surface. The following model predictions of dose to human bronchial epithelial cell nuclei for a 218Po alpha-particle source are provided in units of nanogray (nGy) for specific cell types: secretory 158, preciliated 114, ciliated 44, goblet 86, basal 78, and indeterminate cell nuclei 73. The absorbed dose to specific types of rat bronchial epithelial cell nuclei was also predicted: secretory 237, precillated 216, ciliated 203, goblet 204, basal 200, and indeterminate cell nuclei 166 nGy. These and other results indicate that human and rat airway dosimetry have significant differences that may contribute to the differences in cancer cell induction between the two species.

Association between histamine-containing mast cells and sensory nerves in the skin and airways of control and capsaicin-treated pigs

Abstract: The association between mast cells (visualized by routine staining and immunohistochemistry for histamine) and capsaicin-sensitive nerves (containing calcitonin gene-related peptide (CGRP) and substance P (SP)) was studied in the pig. In the 1-ethyl-3(3-diethylaminopropyl)carbodiimide (EDCDI)-fixed skin tissue, histamine-containing mast cells and CGRP/SP-positive nerves were found in close association around blood vessels. In the EDCDI-fixed airway mucosa, only single histamine-containing mast cells were detected. However, many alcian blue-positive mast cells were found, sometimes close to the airway epithelium where CGRP/SP-containing nerve fibres were absent 2 days after systemic capsaicin pretreatment, but no changes in the number and distribution of tissue mast cells, granulocytes or lymphocytes, or the number of blood leukocytes were detected. Local injection of allergen, histamine and capsaicin into the skin of pigs actively sensitized with ascaris antigen caused a rapid light red-flare (vasodilation) reaction. Allergen and histamine, but not capsaicin, also produced plasma protein extravasation. In contrast to the absent flare, the protein extravasation response still occurred in capsaicin-treated pigs. The sensitivity to ascaris antigen was mediated by an IgE-like antibody. We conclude that a functional and morphological relationship exists between histamine-containing mast cells and capsaicin-sensitive sensory nerves in the pig skin. Mast cells and sensory nerves are also found in the airway mucosa and appear to be closely associated with the epithelium.

Inflammation and cell-cell interactions in airway hyperresponsiveness.

Abstract: Airway hyperresponsiveness results from the conversion of normally reactive airways to a state of augmented responsiveness to constrictor stimuli. Although the mechanism accounting for the induction of airway hyperresponsiveness remains elusive, recent investigations have suggested that inflammation may be a sine qua non for human asthma. Numerous experimental models have demonstrated the necessity of circulating granulocytes as mediators of augmented bronchoconstriction during immune challenge. It is not known how granulocytes are targeted for selective migration to the conducting airways of the lung during hyperresponsive states; however, recent evidence implicates the upregulation of granulocyte adhesion molecules on both the endothelial and epithelial surfaces of the airway. There is evidence that during migration diapedesis, granulocytes interact with epithelial and endothelial cells to produce regionally secreted mediators that upregulate the responsiveness of adjacent airway smooth muscle and/or cause lumenal edema, thus augmenting the effect of constrictor stimuli. Most evidence suggests that the eosinophil is the most important granulocyte in these responses and that eosinophilic infiltration and activation may account for the unique, spasmodic, and cyclic nature of hyperreactive airways. The molecular biology of the eosinophil granule proteins has characterized four distinct substances, each of which exerts potential cytotoxic effects on airway epithelium by different mechanism. In addition, at least one of these proteins, the major basic protein, appears to cause direct, noncytotoxic stimulation of epithelial secretion that upregulates nonspecifically the response of airway smooth muscle to contractile stimuli. The recognition of inflammation as the essential component to airway hyperresponsiveness provides a fresh approach to a difficult problem and suggests a host of novel therapies for human asthma.

Differential adhesion of Pseudomonas aeruginosa to human respiratory epithelial cells in primary culture.

Abstract: Human nasal polyps in outgrowth culture were used to study the Pseudomonas aeruginosa adhesion to respiratory cells. By scanning electron microscopy, P. aeruginosa were seen associated with ciliated cells, but by transmission electron microscopy, bacteria were never seen at the interciliary spaces or attached along cilia, but were identified trapped at the extremities of cilia, usually as bacterial aggregates. A fibronectin-containing fibrillar material was seen associated with aggregated bacteria. By time-lapse video microscopy, bacteria were seen to aggregate in the culture medium following their addition to the culture wells. Progressively, these aggregates were trapped by cilia or attached to migrating cells of a lower cell layer that protruded beneath the upper layer cells, at the outgrowth periphery. P. aeruginosa adhesion to these lower cell layer migrating cells was significantly higher than to ciliated or nonciliated cells of the upper cell layer. Migrating cells were intensely labeled by the complexes Con A and arachis hypogea agglutinin (PNA)-FITC, in contrast to the other cells. The percentage of PNA-labeled cells with attached bacteria was significantly higher than that without bacteria. These results suggest that changes of cell surface glycoconjugates related with cell migration may favor P. aeruginosa adhesion to respiratory cells.

Eicosanoids and Platelet-activating Factor in Allergic Respiratory Diseases

Abstract: The nature of the lipid mediators released at an inflammatory site in the airways is dependent not only on the individual cells and inflammatory stimuli present but also on a complex interaction between neighboring cells and their lipid products. These lipid mediators share overlapping activities, and current research is directed toward determining the critical molecules involved in the pathogenesis of particular inflammatory states.How may the release of these lipid mediators play a role in the pathogenesis of asthma? Allergic persons after inhalation of specific allergen have a dual bronchospastic response. The early asthmatic response occurring shortly after allergen challenge is most likely secondary to the action of bronchoconstrictor molecules (e.g., LTC4, PGD2, PAF) released by human lung mast cells as a consequence of IgE-mediated degranulation. An inflammatory process then occurs in the airways that is characterized by an influx of eosinophils and neutrophils into the airway epithelium and bronch...

Calcium regulation of ciliary beat frequency in human respiratory epithelium in vitro.

Abstract: 1. The changes in ciliary beat frequency (CBF) of human nasal respiratory epithelial cells were measured in vitro with a photometric technique following exposure to either 4-bromo-calcium ionophore A23187 (4-Br-A23187) or trifluoperazine (TFP), an inhibitor of calmodulin-sensitive calcium-dependent protein kinases. Changes in intracellular free calcium concentrations in response to 4-Br-A23187 were studied using a fluorescent dye (Fura-2). 2. Addition of 10(-5) M-4-Br-A23187 caused a time-dependent (P less than 0.01) rise in CBF. The increment in CBF was statistically significant 10 min after challenge (+10%; P less than 0.01) and was sustained for at least 1 h, with maximal stimulation after 40 min (+ 18%; P less than 0.01). 3. Exposure to 10(-5) M-4-Br-A23187 caused an immediate increase in intracellular free calcium concentration, which preceded the rise in CBF. 4. TFP (10(-4) M) caused a reduction of baseline CBF (-10%; P less than 0.01) and prevented the expected rise when the cells were subsequently exposed to 10(-5) M-4-Br-A23187. 5. We conclude that: (1) calcium ionophore stimulates the CBF of human respiratory cells; (2) this effect is mediated through a calmodulin-sensitive system, since it is abolished in the presence of TFP; (3) the same pathway appears to control the basal CBF of these cells, since TFP also decreases CBF.

Effect of cyclic AMP on ciliary activity of human respiratory epithelium

Abstract: In order to investigate the effect of cyclic adenosine monophosphate (cAMP) on ciliary beat frequency (CBF) in human respiratory epithelium, cells were brushed from the inferior nasal turbinates of three groups of ten subjects: awake adults (aged 20-34 yrs), anaesthetized children (2-15 yrs) and anaesthetized adults (19-61 yrs). Cells from the awake adults were also studied after storage for 24 h in tissue culture medium. CBF was measured in vitro with a photometric technique at room temperature (22.0 +/- 1.5 degrees C). Samples were mounted in a perfusion chamber and challenged with either control solutions, dibutyryl cAMP (10(-4) or 10(-3) M), or the cyclic nucleotide-dependent protein kinase inhibitor 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H-7). Dibutyryl cAMP (10(-3) M) caused a significant increase in CBF in all groups studied: awake adults (+1.1 Hz; p less than 0.01), anaesthetized children (+1.2 Hz; p less than 0.01), anaesthetized adults (+1.2 Hz; p less than 0.01), stored cells (+1.1 Hz; p less than 0.01). This response was inhibited by preincubation with H-7 (10(-4) and 10(-3) M). It is concluded that cAMP is a regulator of ciliary activity in human respiratory epithelium.

Reconstitution of tracheal grafts with a genetically modified epithelium

Abstract: A rational approach to the development of gene therapies for cystic fibrosis requires a better understanding of the cellular targets for gene transfer in the airway epithelium. We have used recombinant retroviruses to study the dynamics and lineage relationships of a regenerating rat tracheal epithelium. Primary cultures of tracheal epithelial cells were exposed to lacZ-transducing retroviruses and subsequently seeded into denuded trachea that were implanted into BALB/c (nu/nu) mice. The grafts developed a fully differentiated mucociliary epithelium containing large clones of lacZ-expressing cells with virtually all cell types represented within each clone. These data are most consistent with gene transfer into a putative progenitor cell that is capable of extensive self renewal and pleuripotent development. Vector-specific variation in transgene expression was noted in the various cell types.

Transcellular sodium transport in cultured cystic fibrosis human nasal epithelium.

Abstract: Cystic fibrosis (CF) airway epithelia exhibit raised transepithelial Na+ transport rates, as determined by open-circuit isotope fluxes and estimates of the amiloride-sensitive equivalent short-circ...

Effects of Bordetella pertussis infection on human respiratory epithelium in vivo and in vitro.

Abstract: Bordetella pertussis infection probably involves attachment to and destruction of ciliated epithelial cells, but most previous studies have used animal tissue. During an epidemic, nasal epithelial biopsy specimens of 15 children (aged 1 month to 3 1/2 years) with whooping cough were examined for ciliary beat frequency, percent ciliation of the epithelium, and ciliary and epithelial cell ultrastructure. In addition, the in vitro effects of filtrates from a 24-h broth culture and of tracheal cytotoxin derived from B. pertussis on human nasal tissue organ culture were measured. B. pertussis was cultured from nasal swabs from 12 children. The mean ciliary beat frequency of their nasal biopsy specimens, 11.3 Hz (range, 10.4 to 13.0 Hz) was similar to that found in biopsy specimens from 10 normal children (mean, 12.5 Hz; range, 11.8 to 13.5 Hz). The abnormalities of the epithelium observed in 14 of 15 patients were a reduction in the number of ciliated cells, an increase in the number of cells with sparse ciliation, an increase in the number of dead cells, and extrusion of cells from the epithelial surface. In vitro, neither culture filtrate nor tracheal cytotoxin had any acute effect on ciliary function, but culture filtrate and tracheal cytotoxin (1 and 5 microM, respectively) caused extrusion of cells from the epithelial surface of turbinate tissue, loss of ciliated cells, an increased frequency of sparsely ciliated cells, and toxic changes in some cells. These changes were dose dependent and progressive, and between 36 and 90 h ciliary beating ceased. The observations made with patient tissue confirm that B. pertussis infection damages ciliated epithelium, and the in vitro experiments suggest that tracheal cytotoxin may be responsible for the abnormalities observed in vivo.

Drug-metabolizing enzymes in liver, olfactory, and respiratory epithelium of cattle.

Abstract: The drug-metabolizing enzymes of olfactory and respiratory epithelium of cattle were determined. The data of nasal tissues were compared to those of bovine liver. Both oxidative and nonoxidative enzyme activities were investigated. Many compounds including testosterone were used as substrates for the P450-dependent monooxygenase activities. The results demonstrated that the P450 content and all the activities assayed including reduced nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase were much higher in the olfactory than in the respiratory mucosa and for some activities (hexamethyl-phosphoramide and dimethylnitrosamine N-demethylase, aniline hydroxylase, and ethoxycoumarin O-deethylase) the values in the olfactory tissue were even markedly higher than those of liver. Also the activities of some nonoxidative enzymes such as glutathione S-transferase, uridine 5′-diphosphate (UDP)-glucuronyl-transferase, and epoxide hydrolase were higher in the olfactory than in the respiratory mucosa but lower than in liver. The results taken together suggest that the olfactory and respiratory epithelium of cattle, which contain in addition to a wide array of nonoxidative enzymes multiple forms of P450, can be useful and easily available tissues to study the biotrans-formation processes of odorants.

Functional Morphology of Epithelium of the Small Intestine

Abstract: The sections in this article are: 1 General Considerations 1.1 Supporting Elements of Epithelium 1.2 Compartmentalization of Epithelium 1.3 Contribution of the Paracellular Pathway to Secretion and Absorption 1.4 Polarity of Epithelial Cells 2 Structure of “Absorbing” Epithelial Cells 2.1 Villus Absorptive Cells 2.2 M Cells 3 Structure of “Secreting” Epithelial Cells 3.1 Undifferentiated Crypt Cells 3.2 Goblet Cells 3.3 Enteroendocrine Cells 3.4 Paneth Cells 4 Structure of Epithelial Cells not Currently known to have Absorptive or Secretory Function 4.1 Tuft Cells 4.2 Cup Cells

Calcitonin gene-related peptide and its mRNA in pulmonary neuroendocrine cells and ganglia.

Abstract: The occurrence of calcitonin gene-related peptide (CGRP) and it's mRNA was studied in lungs of rats and piglets using in situ hybridization with two synthetic oligonucleotide probes followed by immunocytochemistry (ICC). CGRP mRNA was present in pulmonary neuroendocrine cells (PNEC) of both the solitary type and cluster type (neuroepithelial body; NEB) at all levels of the airway epithelium from bronchi to alveoli. The distribution of labelled cells was similar to that previously described with ICC. The 44-mer probe provided stronger hybridization signal than the 34-mer and the two combined increased labelling slightly. Formalin fixation reduced labelling and tended to increase background. Labelling for CGRP mRNA was evenly distributed over the cytoplasm, whereas CGRP-like immunoreactivity (LI) usually was of highest intensity toward the base of the PNEC, suggesting basal accumulation of synthesized peptide. CGRP-LI was also observed in occasional rat ganglia and in some, but not all, piglet ganglia. These local neurons may contribute to the CGRP fibers of airways and vasculature, and could theoretically bridge their dendrites and axons between NEB and the effector organ (e.g. artery or arteriole) thus accomplishing a function similar to the postulated axon reflex.

Rat Lung Alveolar Type I Epithelial Cell Injury and Response to Hyperoxia

Abstract: Hyperoxia has been shown to cause extensive lung injury, which involves all components of the alveolar septum, although the type I epithelium has generally been reported to be resistant to significant injury. Electron microscopic morphometry was performed to define changes in volumes of subcellular components of alveolar epithelial cells in rats exposed to 85% O2 for 0, 7, and 14 d. Because of their large size, type I cells in control animals actually contain a greater volume of most of the organelles involved in cell metabolism than do type II cells. Hyperoxic exposure causes a dramatic change in the subcellular composition of the average type I cell, suggesting significant injury and/or response. Injury was suggested by the finding that lysosomes plus peroxisomes increased 1,250% after 7 d in hyperoxia and remained elevated by 200% after 14 d of exposure. Volumes of mitochondria, rough endoplasmic reticulum, smooth endoplasmic reticulum, and Golgi apparatus increased by 100%, 51%, 91%, and 500%, respect...

Proliferation, differentiation and ciliary beating of human respiratory ciliated cells in primary culture

Abstract: The growth, differentiation, ciliary beating pattern and frequency of human respiratory ciliated cells in primary culture were studied by scanning and transmission electron microscopy and by videomicroscopy. The epithelial cells were obtained as outgrowth from explants of adult nasal polyps. When the explants were grown on type-I and type-IV collagen substrates in a standard serum-free, hormone-supplemented medium, a high percentage of ciliated cells (range 29±5% to 37±6%) was present within 2 days of culture. After 5 days of culture, the percentage of ciliated cells near the explant was 51±5%. Most of the cultured ciliated cells (85%) were characterized by individual cilia showing a coordinated movement during the beat cycle and a beating frequency (13.3±1.3 Hz) similar to that reported in vivo. In the other 15% of the ciliated cells, the dyskinetic cilia were aggregated into clumps and characterized by a rigid and planar bending movement and a lower (P<0.01) beating frequency (10.7±1.4 Hz). It is suggested that the latter type of cell, already described during fetal development, might be an intermediate type of ciliated cell which appears temporarily during the surface respiratory epithelial differentiation.

The airway epithelium : physiology, pathophysiology, and pharmacology

Abstract: In 18 contributed chapters (including one by the editors), this reference discusses molecular, biochemical, physiological, and pharmacological roles of the epithelium both in healthy and diseased airways providing detailed descriptions of the structures and functions of different airway epithelial c