Mucociliary transport function and damage of ciliated epithelium

The influence of epithelial damage on mucociliary transport was studied in relation to the amount of mucus. The mucosal epithelium of mucus-depleted frog palate was dissected and mounted on a plastic plate. Mechanical damages were created on the frog mucosa by pressing a different thickness of boards (2, 3, 5, and 8 mm). Two different amounts of frog mucus (7.9 microL [small amount of mucus (S-mucus]]) and 51.0 microL [large amount of mucus [L-mucus]]) were acpplied on the frog mucosa witih and without mucosal damage. There was no difference in mucociliary transport rate (MTR) on undamaged frog mucosa between S-mucus and L-mucus. However, on the damaged mucosa, MTR of S-miucus was significantly decreased compared with that of L-mucus. Moreover, capability of mucus transportation across the mucosal damage was significantly lower in S-mucus than in L-mnucus. Results indicate that the larger the mucus amount becomes, the more the mucus travels the damaged epithelium. Moreover, MTR of L-mucus was decreased with increasing the degree of epithelial damage. This study indicates that the degree of loss of cilia is an important factor of mucociliarn deceleration.     

Mucociliary activity and the diving reflex

It has previously been shown that mucociliary activity in the rabbit maxillary sinus is immediately increased after short-term exposure to such airway irritants as cigarette smoke and ammonia vapor. This increase is mediated through the stimulation of capsaicin-sensitive nerve endings. Besides producing the mucociliary effect, these irritants inhibit breathing, a response characteristic of the diving reflex in mammals. Whether an increase in mucociliary activity is part of the diving reflex was investigated by injecting 0.5 mL water into the nasopharynges of anesthetized rabbits. Mucociliary and respiratory responses were compared with the effects of mechanical stimulation (ie, rotating an intranasal catheter until sneezing occurred). Water challenge produced an increase in mucociliary activity of 21.6% +/- 2.4%, a response that began approximately 10 seconds after injection. Mucociliary acceleration was completely blocked by atropine, indicating a cholinergic mechanism, but was unaffected by pretreatment with capsaicin. The respiration rate was inhibited by about 45% after challenge with water. Pretreatment with atropine and capsaicin had no effect on this reduced respiratory rate. Mechanical stimulation of the nasal mucosa accelerated mucociliary activity. This response appeared approximately 4 seconds after stimulation was begun, and occurred simultaneously with the onset of sneezing. The peak increase was 22.0% +/- 2.1%. Sneezing was followed by an increase in the respiration rate of about 40%. Pretreatment with atropine or capsaicin had no effect on respiratory responses, but did inhibit mucociliary acceleration, suggesting that the response is mediated through cholinergic effector neurons after activation of capsaicin-sensitive nerve endings.(ABSTRACT TRUNCATED AT 250 WORDS)     

Regeneration of free grafted respiratory epithelium on severely altered lamina propria.

The lamina propria of nasal mucosa has been thought to play a key role in function and metabolism of respiratory epithelia by allowing exchange of various substances and migratory cells from blood vessels into the epithelium. Here we show that the lamina propria of mucosa transplanted to rat rectus abdominis muscle looses its typical structure and becomes vascularized connective tissue. In the subepithelial space of free grafted respiratory epithelia nasal glands, ducts and nerves degenerate and are no more detectable 3 weeks after transplantation. By contrast the epithelial cell layer regenerates, resulting in a healthy appearing mucosa. Histological and functional controls revealed that regenerated respiratory epithelium lies on a layer of vascularized connective tissue and displays normal cellular differentiation and ciliary function. The present experiments demonstrate that the lamina propria can be replaced by vascularized connective tissue without functional loss of the overlaying epithelium. Thus the results argue against a key role of lamina propria in mucosal function.     

Mucociliary activity and ultrastructural abnormalities of regenerated sinus mucosa in rabbits

The purpose of this study was to observe histologic findings in the regenerated maxillary sinus mucosa and restoration of ciliary activity by measuring the speed of mucociliary transport after complete surgical removal of the maxillary sinus mucosa. The maxillary sinuses of 32 rabbits were opened anteriorly and one side of the sinus mucosa of each animal was completely removed. In 16 animals, the natural ostia were widened, and, in another 16 animals, the natural ostia were left undisturbed. The contralateral, sham-operated sinus was used as a control for each animal. The animals of each group were reanesthetized and the maxillary sinuses were reopened at planned intervals. The speed of mucociliary transport toward the maxillary ostium, determined by India ink particle movement, was reduced to 6.4 mm/min, whereas it was 10.8 mm/min in the control side. Beating cilia were observed in 16% by dark-field microscopy, in contrast to 66% in the control sinus. Pseudostratified columnar epithelia without cilia were present in 12%, with the remaining consisting of pseudostratified ciliated columnar epithelia (88%). Light microscopic examination showed increase in submucosal fibrotic proliferation, decrease in submucosal glands, and infiltration of inflammatory cells. Under transmission electron microscopy, abnormal cilia such as compound cilia or edematous cilia were frequently found in the regenerated specimens. These observations suggest that mucociliary clearance of the regenerated sinus mucosa may be significantly diminished compared with that of the original mucosa.     

Differences in Mucociliary activity of volunteers undergoing Ramadan versus Nineveh fasting

This study, aimed to evaluate the difference in mucociliary clearance among volunteers who underwent Ramadan versus Nineveh fasting regimens as well as the difference between the fasting period and 4 weeks following the fasting period in both groups. In this study, two different fasting groups were established: Ramadan (fasting for an average of 15 h for 29 consecutive days, n = 40) and Nineveh (60 h of nonstop fasting, n = 26). Subjects in each group underwent saccharin testing twice: at the end of the fasting period prior to resumption of eating and at 4 weeks after the end of Ramadan or Nineveh fasting. Statistical analysis was performed using the Mann–Whitney U-test, Wilcoxon, Chi-square, and paired t test. A p value less than 0.05 was considered statistically significant. Forty subjects who underwent Ramadan fasting and 26 subjects who underwent Nineveh fasting were included in this study. Of the 66 study participants, 34 (51.5 %) were men and 32 (48.5 %) were women. Their median age was 31 years (range 17–70 years) for Nineveh fasting subjects and 40 years (range 17–70 years) for Ramadan fasting subjects. Chi-square tests revealed no significant difference between the Ramadan and Nineveh fasting groups in gender (p = 0.418), and the Mann-Whitney U-test showed no difference in age. A statistically significant difference was found in the mucociliary clearance time between the Nineveh fasting and non-fasting periods (p = 0.013). Using Wilcoxon signed-rank tests, we found no significant difference in the mucociliary clearance time between the Ramadan fasting and control (4 weeks after the fasting period) periods (p = 0.121). The percentage difference between the fasting and control periods was similar between groups and was not statistically significant for the Ramadan and Nineveh fasting groups (p = 0.086). The results of the present study indicated that long-term fasting with hypohydration contributed to the deterioration of nasal mucociliary clearance. Our data indicate that optimal hydration, sleep patterns, and fasting times contribute to proper mucociliary clearance.     

Reconstruction of defects following pharyngolaryngectomy with free transplanted jejunum

We report 10 patients undergoing pharyngo-laryngectomy in whom the pharyngeal defect was reconstructed with a free jejunal graft. This method is technically demanding. The advantages are excellent healing due to the excellent blood supply of the edges of the graft, and the almost unlimited supply of jejunum. The use of this method is justified by the immediate restoration of deglutition.     

Branching microvilli in the nasal respiratory epithelium

In an ultrastructural study of the respiratory epithelial covering of 14 human nasal mucous polyps, some of the microvilli overlying the ciliated cells were shown to exhibit a complex form of branching with a resultant increase in surface area. This apparently original observation is of uncertain significance but is not of definite pathological significance.     

Growth of human respiratory epithelium on collagen foil

BACKGROUND: Clinical application of bioartificial tracheal prosthesis must still be regarded as an experimental concept because restoration of a functional respiratory epithelium outlining the prosthesis is still not possible. Tissue engineering as a relatively new biotechnological discipline may offer new methods in expanding differentiated respiratory epithelium in vitro. In this study we compare two different cell and tissue culture procedures for growing human nasal mucosa on commercially available collagen foil. MATERIAL AND METHODS: Harvested specimens of human nasal mucosa (n = 6, 4 x 4 cm) were placed on collagen foil and incubated as tissue cultures for 4, 6 and 8 weeks. A suspension of enzymatically dispersed nasal epithelium seeded on collagen foil (5 x 10(5) cells) served as control. Cell growth and ciliary beat were monitored through an inverted microscope with Hoffman's modulation contrast and video set-up. Histological examination was performed after 4, 6 and 8 weeks. RESULTS: In the tissue cultures, the collagen foil was initially covered with fibroblasts growing from the mucosa specimen before epithelial cells spread out. The epithelial layer showed mostly ciliated cells which developed metachronous ciliary beat after 4 weeks in vitro. Ciliary activity was observed until the end of the experiments in 8 weeks. New cells on the suspension cultures were mesenchymal and did not exhibit any ciliary activity. CONCLUSIONS: Mucosa specimens seem to be more appropriate for tissue engineering of respiratory epithelium than cell suspensions from nasal epithelium. Collagen foil as tissue scaffold initiates epithelial-mesenchymal interaction and may play an important role in epithelial differentiation of new respiratory epithelium.     

Induction of transformation of human respiratory epithelium in vitro

Summary Malignancy is the result of multistep transformational changes of normal somatic cells. In the case of respiratory epithelial malignancies this process lasts for several years. Many methods have been explored to mimic this process in an extracorporal model. In the present investigation we combined several of these methods. Organ cultures were prepared from tracheal specimens and were then consecutively treated with human papilloma virus, benzo(a)pyrene, methylnitronitrosoguanine and tetradecanoyl phorbol acetate. Identical numbers of organ cultures from the same specimen were maintained without exposure to carcinogens. After 6 weeks these cultures were further cultivated either in mixed cultures (MC) with autologous isotopic fibroblasts or under the kidney capsule of the nude mouse (SRC). These two methods were combined after a few months: MC cells were transplanted under the SRC or SRC transplants were explanted in cell culture. This long-term selection procedure revealed striking differences between control and treated organ cultures. Three-dimensional structures containing epithelial cells were isolated from both organ cultures but survived more than 3 months only from treated cultures. Only MC from treated organ cultures produced nodules under SRC. The incidence and morphology of the nodules in the SRC were directly related to carcinogen treatment, with more nodules with pronounced epithelial cell atypia obtained from treated organ cultures. MC and SRC showed the importance of a time factor for selecting cells with changed growth behavior —increased time increased the incidence of such cells.     

Neonatal lingual choristoma with respiratory and gastric epithelium

Lingual choristomas are rare entities that typically present as benign cystic masses that are lined with a variety of heterotopic epithelia. Lingual choristomas that are lined with respiratory and/or gastric or intestinal mucosa are believed to derive from pluripotential cells of the embryonic foregut. We describe a neonate with a lingual cyst that was lined predominantly by respiratory epithelium and focally by gastric foveolar epithelium, and we review the terminology, etiology, and management of lingual cysts of presumed foregut origin.     

Does the use of free transplanted jejunum segments in advanced laryngeal and hypopharyngeal cancer prolong survival? A matched-pair analysis]

The effect of free transplanted jejunum autografts, inserted after resection of extensive squamous cell carcinoma of the larynx and hypopharynx is evaluated in terms of survival and the development of local and regional recurrences. In a matched-pair analysis, 22 patients with jejunum transplants were compared with 44 patients with the same performance status, in whom after laryngopharyngectomy, the pharynx had been closed with local mucosa. The cumulative survival rate was calculated using the Kaplan-Meier method; the statistical comparison of the survival curves of the two groups was made with the Mantel-Haezel test. Patients of the study group had a statistically significant (p less than = 0.01) better survival rate than those of the control group, the 50% survival rate being 36 and 11 months, respectively. Local recurrences occurred in 9.1% of the patients in both the study group and in controls, and regional recurrences in 40.8 and 43.2%, respectively. This militates against the possibility that the surgery in patients in whom reconstruction with jejunum was possible might have been more radical. Further, it may be speculated that the statistically significant better survival rate is due to the jejunum itself, presumably to a tumourprotective effect of the lymphatic tissue of the transplant.     

The distribution of free calcium ions in the cholesteatoma epithelium

The distribution of free calcium ions in normal skin and cholesteatoma epithelium was investigated using the oxalate precipitation method. In agreement with previous observations, we could demonstrate a calcium ion gradient in normal epidermis where the cells in stratum basale and spinosum reside in an environment containing relatively low concentrations of calcium ions, whereas the outer stratum granulosum contained abundant calcium. The concentration declined precipitously in the stratum corneum. In contrast, in cholesteatomas, the gradient was perturbed in some areas of the nucleated layers and areas appeared where oblong accumulations of free calcium ions were found basally in the stratum. These findings provide evidence that fluctuations in epidermal calcium in cholesteatoma epithelium may underlie the abnormal desquamation, may contribute to the formation of an abnormal permeability barrier and may regulate terminal events in epidermal differentiation.     

Organotypic (raft) culture of biopsy-derived upper respiratory epithelium

OBJECTIVE: The objective of this study was to derive a reliable technique for culturing biopsy-derived upper respiratory epithelium in a system that supports epithelial differentiation and simulates the normal epithelial life cycle. STUDY DESIGN: The authors conducted a prospective study of modification and development of an in vitro tissue culture method. METHODS: Thirty biopsy specimens from 16 individuals with recurrent respiratory papillomatosis and chronic tonsillitis, pretreated to prevent bacterial and fungal overgrowth, were digested with trypsin to create a supernatant of individual cells. The cells were plated and incubated. At 14 to 16 days, the resulting colonies were placed on a wire cloth raft and fed through diffusion from the underlying culture medium in an air-liquid interface. RESULTS: Eight specimens were successfully cultured for an average of over 32 days. The longest duration of sustained growth was 60 days. Low-risk human papillomavirus specimen-based cultures reproduced infection in cultured squamous epithelium with corresponding histopathologic features indicating a high level of stratification and differentiation. CONCLUSIONS: Unlike commercially available cell lines, biopsy-derived material is predisposed to contamination, and successful in vitro culture and experimentation creates many unique challenges. An organotypic culture system, capable of reproducing the differentiation-dependent replication cycle of human papillomavirus, may be used for culturing biopsy-derived specimens for a variety of studies.     

Cellular differentiation after free grafting of respiratory epithelia

Summary Since there have been few investigations on the free grafting of respiratory epithelia, the aim of our present experiments was to establish whether it was possible to carry out such grafting in an animal model. Purebred strains of Lewis blood group rats were used to avoid host-versus-graft rejections of mucous membrane transferred from a donor to a recipient animal. Respiratory epithelia from the nasal septum were transplanted to the rectus abdominis muscle. Muscle and epithelial layers were then removed 4 months later. Using light and electron microscopy the function of the grafted ciliated epithelia — i.e. of the ciliated and goblet cells -could be demonstrated. These findings showed that respiratory epithelia heal when grafted onto a recipient site which has an adequate blood supply but do not lose their initial differentiation or functions. The results obtained in this experiment are important clinically for reconstruction of the respiratory tracts.     

Histologic study of the effect of postoperative irradiation on free transplanted jejunal segments

After the reconstruction of defects resulting from the resection of advanced tumors from the upper aerodigestive tract using free microvascular anastomized jejunum, the autotransplant is influenced by local radiotherapy (cumulative dose 50-70 Gray). Biopsies were taken from 15 patients, stained with haemotoxilin-eosin and Giemsa and compared by means of light microscopy with jejunum taken at the time of transplantation. It was possible to observe a widened mucosal and submucosal space two to three months after radiotherapy, similar to the clinical impression of a radiogenic enteritis. The villi were flat and shortened with no or slight epithelial lesions. Additionally, it was possible to observe an inflammatory infiltration consisting mainly of neutrophilic granulocytes, edemas, and telangiectases. The latter were also evident in nonirradiated autotransplanted jejunum and are therefore not only caused by irradiation. One year after radiotherapy the mucosal membrane was atrophic. Fibrosis was to be seen in the lamina propria, accompanied by widened muscularis mucosae. The submucosal space was also widened and fibrotic to a varying degree. It was possible to detect varying stages of alteration in the vascular system up to a complete obliteration. After two years, changes were more pronounced. At no time could any alteration in the nervous system of the plexus submucosus be observed. All of these changes have to be interpreted as a consequence of irradiation. However, lubrication of the mucosal surface and the motility of the transplant are not altered severely by irradiation and therefore the desired functions of the free transplanted jejunal grafts, such as swallowing and phonation, are carried out sufficiently.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cytologic aspects of the nasal respiratory epithelium throughout the menstrual cycle

A prospective study was performed to investigate the changes in nasal cytology that occur in healthy premenopausal women throughout the menstrual cycle. Eighty-eight women with an ovulatory menstrual cycle underwent nasal sampling with a cytobrush by direct vision of the middle and inferior nasal turbinates during the follicular, periovular, and luteal phases of the menstrual cycle, and the specimens were evaluated with the maturation index. Hematoxylin-eosin staining showed the cytologic aspects of the nasal respiratory epithelium and of vaginal smears according to the three different phases of the menstrual cycle. Along with the vaginal cells, the nasal respiratory epithelium is an ovarian steroid target.