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The bronchiolar ciliated cells of rats usually contain two large electron-dense bodies which are individually surrounded by a unit membrane. They lie in a well-defined supranuclear position and may indent the nucleus. The dense material is digested by pepsin, suggesting it is composed of protein. The origin and function of these bodies are still unknown.
Examination of the epidermis of Rana temporaria in various stages of development revealed the presence of densely ciliated cells from the late neurula until shortly before metamorphosis. Unlike the other epidermal cells, these ciliated cells do not divide; once formed, they are constant in number until they disappear. In shape, size, and structure, however, they vary depending on stage of development and on their position in the body. In older larval stages and young tadpoles they are fully differentiated and strongly basophilic. Their function is to improve the hydrodynamic properties of the larval body, and hence ultimately to optimize the energy balance during locomotion.
Sendai virus is a common respiratory pathogen in rodents. In the airways of rats infected with Sendai virus, viral antigen is present in epithelial cells, but whether all types of epithelial cells are infected is unknown. Because each type of epithelial cell has specific functions that could be affected by viral infection, we asked whether ciliated cells, secretory cells, and basal cells of the rat tracheal epithelium become infected by Sendai virus. We inoculated pathogen-free rats intranasally with Sendai virus, killed the rats 1 to 12 days after inoculation, and prepared the tracheas for double-labeling immunohistochemistry and for electron microscopy. In other studies, we maximized the infection by inoculating rats with a 100-fold higher titer of the virus, by inoculating weanling rats, or by inoculating tracheal explants with Sendai virus in vitro. We also determined whether Sendai virus can infect basal cells of tracheal explants after removal of the overlying columnar epithelial cells. Immunohistochemical studies showed that at the peak of the infection (5 days after inoculation), 30% of the surface epithelial cells stained for Sendai virus antigen, but no basal cells were stained. Electron microscopic examination confirmed the presence of viral particles in ciliated cells and secretory cells, but none were found in basal cells. No basal cells were infected under the conditions that maximized the infection. We conclude that ciliated cells and secretory cells of the rat tracheal epithelium become infected by Sendai virus, but basal cells do not become infected.
Axonemal dyneins are molecular motors that drive the beating of cilia and flagella. We report here the identification and partial cloning of seven unique axonemal dynein heavy chains from rat tracheal epithelial (RTE) cells. Combinations of axonemal-specific and degenerate primers to conserved regions around the catalytic site of dynein heavy chains were used to obtain cDNA fragments of rat dynein heavy chains. Southern analysis indicates that these are single copy genes, with one possible exception, and Northern analysis of RNA from RTE cells shows a transcript of approximately 15 kb for each gene. Expression of these genes was restricted to tissues containing axonemes (trachea, testis, and brain). A time course analysis during ciliated cell differentiation of RTE cells in culture demonstrated that the expression of axonemal dynein heavy chains correlated with the development of ciliated cells, while cytoplasmic dynein heavy chain expression remained constant. In addition, factors that regulate the development of ciliated cells in culture regulated the expression of axonemal dynein heavy chains in a parallel fashion. These are the first mammalian dynein heavy chain genes shown to be expressed specifically in axonemal tissues. Identification of the mechanisms that regulate the cell-specific expression of these axonemal dynein heavy chains will further our understanding of the process of ciliated cell differentiation.
AIM: Airways humidification during mechanical ventilation (MV) can be performed by means of heat and moisture exchangers (HME). Good performance of selected hygroscopic HME was shown in terms of tracheal temperature and humidity control and low tube obstruction rates. However, few data are available on their effects on tracheobronchial ciliated cells. The purpose of this study was to evaluate the effects of 2 different HME on ciliated cell during MV. METHODS: Twenty consecutive patients undergoing elective surgery lasting <4 h were randomly assigned to be treated with Rusch (Group 1) or Mediflux (Group 2) hygroscopic HME. The morphology of tracheobronchial ciliated cells was evaluated from cytologic smears of endotracheal aspirate. Smears were prepared by using the thin-prep processor, stained using the Papanicolau method and examined in triplicate: recognizable respiratory cells were graded on a six-point scale, according to the normal appearance of cilia, cytoplasm and nucleus. RESULTS: In Group 1, 178.3+37 cells were retrieved from aspirates and , 155.6+58 in Group 2 (NS). The score was 739+241 in Group 1 and 617+329 in Group 2 (NS). Cilia and end plate were undamaged in 80+17% and 81+20% cells respectively in Group 1 and in 56+23% and 62+22% cells respectively in Group 2 (P<0.01 and <0.05). CONCLUSIONS: During MV epithelial tracheobronchial cells can be affected by the humidification device used. Our findings suggest that the 2 HME tested in the present study have a different impact on ciliated cells structure.
As opposed to the virtually constant load exerted by water on the cilia of ciliated protozoa, the hydrodynamic load on respiratory cilia can undergo broad variations because of changes in the rheologic properties of mucus. When water-rowing ciliated cells are exposed to increased viscosity (1 to 50 cP), their beat frequency decreases exponentially. According to Newton's fluid dynamic theory, this outcome is expected for an engine that generates constant force. However, the findings reported here indicate that when mucus-propelling respiratory ciliated cells are exposed to high viscous loads, ranging from 12 to 150 cP, the frequency of ciliary beat decreases only slightly, whereas the beat amplitude remains virtually constant. These observations suggest that ciliated cells of the respiratory tract have a functional reserve that allows them to autoregulate their mechanical output in response to the changes in viscosity to which they are normally exposed in the airway.
Previous investigations of the expression of chromogranin A (CgA) have been performed primarily in neuroendocrine tissues containing amine and peptide secretory vesicles. More recently it has been shown that CgA, as a high capacity Ca2+ storage protein, interacts with the inositol 1,4,5-trisphosphate receptor/Ca2+ channel (InsP3R) which has been found to be selectively localized in oviductal cells of the mouse. To examine a possible role of this coupling in the Ca2+-dependent ciliary movement, we investigated the topographical and cellular distribution of cells positive for CgA and inositol 1,4,5-trisphosphate receptor type 2 (InsP3R2) in the bovine oviduct at different stages of the oestrous cycle. Using immunohistochemical techniques on paraffin-embedded tissue we have successfully shown that CgA is selectively expressed in ciliated cells of the bovine oviduct. The labelled cells show intense positive staining in the apical surface area in close vicinity to the ciliary apparatus. CgA-positive ciliated cells are most frequently observed at dioestrous while a lower number appears at oestrous. Additionally, secretory and intraepithelial neuroendocrine cells consistently do not stain with the CgA-antiserum. We then investigated whether the reported expression of the InsP3R in oviductal cells of the mouse corresponds to the expression of the InsP3R in bovine oviductal cells. Using a polyclonal antibody to the type 2 InsP3R, we found that the receptor is also selectively expressed in a similar matter to CgA in the apical cytoplasm of ciliated cells. This is the first morphological demonstration of the colocalization of CgA and InsP3R in epithelial ciliated cells of the bovine oviduct. Our results suggest that CgA and InsP3R could be involved in controlling the ciliary activity of oviductal epithelial cells.
An autopsy case of ciliated-cell adenocarcinoma of the pancreas was reported. A 65-year-old man, who had undergone subtotal gastrectomy because of advanced gastric carcinoma 6 years previously, died of obstructive jaundice. The autopsy revealed a primary tumor in the head of the pancreas and multiple metastatic foci in the liver, lungs, and regional lymph nodes. Histologically, the pancreatic tumor was moderately differentiated papillary adenocarcinoma with well developed cilia. The metastatic tumor also showed similar histology. Histologic and ultrastructural features of the tumor were described in detail and the cytogenesis of ciliated-cell adenocarcinoma was briefly discussed.
Eighteen surgical specimens having an adenocarcinoma arising in Barrett's esophagus were reviewed, and special attention was paid to the presence of ciliated cells. The tumors were classified as glandular (9), papillary (4), diffuse (3) and mixed (2) types. Ciliated cells were observed in one specimen, in cystically dilated glands in Barrett's mucosa adjacent to a papillary adenocarcinoma. Ciliated tumor cells were found in three of the four papillary adenocarcinomas. The fourth papillary tumor, 1 mixed papillary-diffuse adenocarcinoma and the remaining 13 adenocarcinomas had no ciliated cells. Thus, the presence of cilia in exfoliated tumor cells from the esophagus should raise the suspicion of a papillary adenocarcinoma arising in Barrett's mucosa.
Studies of the ciliate cell cycle have moved from early examination of its biochemistry with heat-synchronized Tetrahymena through descriptive studies of Paramecium using small synchronous cell samples. These studies described what happens during the cell cycle and provided some initial insights into control, especially the idea that there was a point at which cells became committed to division. This early work was followed by an analytical phase in which the same small sample techniques, combined with gene mutations, were used to tease apart some major features of the regulation of cell growth kinetics, including regulation of macronuclear DNA content and regulation of cell size, the control of timing of initiation of macronuclear DNA synthesis, and the control of commitment to division in Paramecium. The availability of new molecular genetic approaches and new means of manipulating cells en masse made it possible to map out some of the basic features of the molecular biology of cell cycle regulation in ciliates. The challenge before us is to move beyond the 'me-too-ism' of validating the presence of basic molecular regulative machinery underlying the cell cycle in ciliates to a deeper analysis of the role of specific molecules in processes unique to ciliates or to analysis of the role of regulatory molecules in the control of cell process that can be uniquely well studied in ciliates.
Ciliated metaplasia (CM) of gastric mucosa is common in Japanese individuals but rare in whites. We studied 36 consecutive gastrectomies from Chinese individuals for the presence of CM. The gastrectomies were performed for adenocarcinoma (n = 22), benign ulcer (n = 13), and malignant lymphoma (n = 1). Ciliated metaplasia was found in 16 (44.4%) of the stomachs, with equal distribution between male and female patients. Ciliated metaplasia was present in 11 cases (50%) of adenocarcinoma and in five cases (38.5%) of benign ulcer, the difference being statistically insignificant. Contrary to previous studies, there was no increased frequency of CM in gastric mucosa harboring an intestinal-type adenocarcinoma compared with those with non-intestinal-type tumors. Ciliated metaplasia always co-existed with intestinal metaplasia. Colonization by Helicobacter pylori was not associated with an increased incidence of CM. In five cases (22.7%) of adenocarcinoma ciliated tumor cells were found, and all of these cases showed CM in the gastric mucosa. In one of these cases the whole tumor was composed of glands formed by ciliated cells. In the other cases there was a morphologically different nonciliated component. The cilia in the tumor cells showed light microscopic and ultrastructural changes identical to those of the cilia seen in CM affecting the nonneoplastic gastric mucosa. This study documents for the first time the co-existence of CM and ciliated adenocarcinoma in the same stomach. It is concluded that in the Hong Kong Chinese population CM is commonly present in gastric mucosa harboring an adenocarcinoma or benign ulcer. Adenocarcinomas with ciliated cells are strongly associated with CM.
Chronic exposure of men or rodents to low frequency/high intensity (LFHI) noise causes a number of systemic changes that make up the so-called vibroacoustic disease (VAD), a disorder that includes alterations of the respiratory system, namely, of its epithelial layer. We have investigated here the susceptibility of the tracheal epithelium of Wistar rats to in utero and postnatal exposure to LFHI noise by comparing its ultrastructure with that of the tracheal epithelium of control rats and of animals exposed to LFHI noise only after reaching adulthood (8 weeks of age). Scanning electron microscopy (SEM) of the inner surface of rat trachea was used to determine the relative areas covered by ciliated and non-ciliated cells. In rats that were exposed in utero and postnatally to LFHI noise, we observed that out of 100 microm(2) of tracheal epithelium only 31 +/- 14 microm(2) were covered by cilia, whereas in control rats; ciliated cells occupied an average of 60 +/- 18 microm(2) out of 100 microm(2) of the epithelium; this difference between the two groups was statistically significant (p <0.05). In rats that were exposed to LFHI noise only after reaching adulthood, cilia covered 55 +/- 22 microm(2) out of 100 microm(2) of the luminal surface of the trachea, a value that, although lower than that of controls, was not found to be statistically different. We conclude that (1) the tracheal ciliated cells are damaged by exposure of rats to LFHI noise if the animals are kept under this environmental aggression during in utero and postnatal periods; (2) tracheal ciliated cells from adult rats are more resistant to the deleterious effects of LFHI noise than pleura or lung alveolar cells that were shown before to undergo marked changes upon chronic exposure of rats to LFHI noise. These findings suggest a note of caution regarding pregnant women and young children: they should be prevented from areas where LFHI noise occurs, namely, in aircraft and textile industries where this type of environmental hazard is often present.
Intestinal metaplasia of the gastric mucosa occurs commonly in aged Japanese patients and has been discussed in relation to the high incidence of gastric cancer in Japanese. Ciliated cells in the gastric mucosa have frequently been found in association with intestinal metaplasia in the pyloric gland and rarely in the cardiac gland in many Japanese patients, and exceptionally in one Chinese and in one Swedish patient. Electron microscopic examination of 12 Japanese patients has revealed that these structures are not metaplastic stereocilia, but true cilia. Ciliated cells have been found in the basal part of the gastric glands and never in the surface epithelium. The fine structure of the gastric cilia was almost the same as that of normal respiratory cilia. However, in the gastric cilia, most dynein arms were inconspicuous even after tannic acid fixation, indicating that ciliary beating of the gastric cilia is problematic. Abnormal cilia and basal bodies also were found. Ciliated cells have always occurred in association with intestinal metaplasia, therefore this phenomenon might be a type of metaplasia and is named "ciliated metaplasia" of the gastric mucosa.
We investigated the effect of beta-adrenoceptor stimulants on the canine tracheal ciliated cells. A mucosal specimen of the tracheal membranous cell was placed in a chamber containing Hanks' solution. Membrane potential was recorded by an intracellular microelectrode, and ciliary beating was measured by a photoelectrical technique. Isoproterenol and salbutamol in 10(-7) to 10(-4) M caused a concentration-dependent increase in both frequencies of ciliary beating and small electrical oscillatories were superimposed on the membrane potential. Theophylline also increased frequencies of both activities in doses of 10(-5) M and above. Onset of action of theophylline was later than that of isoproterenol or salbutamol. All the above drugs only slightly depolarized the membrane potential, in concentrations of 10(-4) M. Propranolol (10(-7)-10(-4) M) alone had little effect on ciliary beating and electrical activity. However, the effects of isoproterenol and salbutamol were effectively antagonized by propranolol (10(-5) M). Dibutyryl cyclic AMP (10(-7)-10(-4) M) caused concentration-dependent increases in ciliary beating and electrical activity. These results suggest that potent bronchodilators such as beta-stimulants and theophylline increase the activity of tracheal ciliated cells by stimulating the intracellular cyclic AMP system.
This study was based on a method of microphotometrical measurement of the ciliary beat of cells from the human upper respiratory tract. The ciliated cells were acquired by the tissue cultivation of small pieces of nasal mucosa obtained during surgical interventions in the paranasal sinuses. The experiments were performed in a chamber where the cells were superfused by a tyrode solution. The ciliary beat was measured by a microscope photometer built into an inverted microscope. During the measurements the diaphragm aperture of the photometer was positioned over the cilia in such a manner that the changes of light intensity resulting from the movement of the cilia could be registered. The frequency of the ciliary beat was estimated by counting the individual beats. The ciliary beat during control conditions was studied as well as the influence of temperature. Cooling of the experimental chamber resulted in a significant reduction of the frequency of the ciliary beat. The advantages of this single cell preparation of ciliated epithelia for pharmacological investigations are discussed.
We constructed a human recombinant parainfluenza virus type 3 (rPIV3) that expresses enhanced green fluorescent protein (GFP) and used this virus, rgPIV3, to characterize PIV3 infection of an established in vitro model of human pseudostratified mucociliary airway epithelium (HAE). The apical surface of HAE was highly susceptible to rgPIV3 infection, whereas only occasional cells were infected when virus was applied to the basolateral surface. Infection involved exclusively ciliated epithelial cells. There was little evidence of virus-mediated cytopathology and no spread of the virus beyond the ciliated cell types. Infection of ciliated cells by rgPIV3 was sensitive to a neuraminidase specific for alpha2-6-linked sialic acid residues, but not to a neuraminidase that cleaves alpha2-3- and alpha2-8-linked sialic acid residues. This provided evidence that rgPIV3 utilizes alpha2-6-linked sialic acid residues for initiating infection, a specificity also described for human influenza viruses. The PIV3 fusion (F) glycoprotein was trafficked exclusively to the apical surface of ciliated cells, which also was the site of release of progeny virus. F glycoprotein localized predominately to the membranes of the cilial shafts, suggesting that progeny viruses may bud from cilia per se. The polarized trafficking of F glycoprotein to the apical surface also likely restricts its interaction with neighboring cells and could account for the observed lack of cell-cell fusion. HAE derived from cystic fibrosis patients was not more susceptible to rgPIV3 infection but did exhibit limited spread of virus due to impaired movement of lumenal secretions due to compromised function of the cilia.
The presence of ciliated cells has been demonstrated by scanning and transmission electron microscopy in corneal endothelium. This study has been carried out on human cornea in normal and pathological cases and on rabbit's normal cornea. Another study has been lead on regeneration of endothelium after freeze destruction. The cilia cells described have a normal structure. The cilia has nine peripheral groups of tubules without any tubule in the center. The cilia seem to be more numerous in case of corneal disease and during the regeneration of corneal endothelium. The authors compare the presence of ciliated cells in different tissues. This suggest that the potency to form single cilia is present in almost every kind of tissue but there is no proof of their pathological importance. In the corneal endothelium, as in the kidney, cilia seem to have no function of fluid transportation but the possibility for cilia to be a receptor is discussed.
The presence of ATP and adenosine receptors and their role in controlling ciliary activity in oviductal ciliated cells was studied by measuring the ciliary beat frequency (CBF) in oviductal tissue cultures. ATP, adenosine, and related compounds increased the CBF in a dose-dependent manner. We established that P2 receptors of subtype 2Y(2) and P1 receptors of subtype A(2a) mediated the responses to ATP and adenosine, respectively. We found evidence to suggest that stimulation of ciliary activity by ATP requires D-myo-inositol 1,4, 5-trisphosphate [Ins(1,4,5)P(3)] metabolism, intracellular Ca(2+) mobilization, and protein kinase C activation. On the other hand, the adenosine effect is mediated by activation of a G(s) protein-dependent pathway that enhances cAMP intracellular levels. To study the interaction between P2 and P1 receptors, cells were stimulated simultaneously with both agonists. We observed a synergistic increase of the CBF even at agonist concentrations (100 nM) that did not produce a significant response when added separately to the culture. Furthermore, a blocker of the cAMP pathway produced a reduction of the ATP response, whereas a blocker of the Ins(1,4,5)P(3) pathway also produced an inhibition of the adenosine response. Our evidence demonstrates that both ATP and adenosine receptors are present in a single ciliated cell and that a mechanism of cross talk could operate in the transduction pathways to control ciliary activity.