Mucociliary clearance in chronic sinusitis: related human nasal clearance and in vitro bullfrog palate clearance

Reversal of Chronic Rhinosinusitis-Associated Sinonasal Ciliary Dysfunction

Background

Although multiple etiologies contribute to the development of chronic rhinosinusitis (CRS), a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, leading to stasis of sinonasal secretions, with subsequent infection and/or persistent inflammation. Proper therapeutic intervention typically restores mucociliary activity, suggesting that the pathophysiological process(es) responsible for CRS-associated mucostasis may be reversible. We previously demonstrated a blunted response of CRS sinonasal cilia after purinergic stimulation. This study investigated whether the blunted ciliary response is unique to purinergic stimulation and addressed whether the blunted effect is primarily caused by local CRS-associated mediators or inherent genetic defects in ciliary function.

Methods

A dual temperature-controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal as well as cholinergic, adrenergic, and purinergic stimulation of cilia in human sinonasal mucosal explants. Additionally, enzymically dissociated sinonasal ciliated cells were maintained ex vivo in submersion, on glass coverslips, and assessed daily for purinergic ciliary beat frequency stimulation.

Results

Cholinergic and adrenergic stimulation generally were blunted in mucosal explants obtained from CRS patients. Ex vivo maintenance of samples demonstrated that the majority of CRS samples developed a stimulatory phenotype within 36 hours of culturing.

Conclusion

CRS is a common debilitating disease principally affecting sinonasal epithelial function with a resultant diminution of mucociliary transport. Presently, little is known about how this disease process affects the sinonasal epithelial ciliated cells. Our data suggest that ciliary response to environmental insults is blunted in a reversible manner in CRS patients.

Regional Analysis of Sinonasal Ciliary Beat Frequency

Background

Mucociliary clearance, a primary host defense mechanism, depends on mucus production and its clearance by the coordinated beating of cilia lining the airways. Numerous investigations have analyzed ciliary activity in brushings from the inferior turbinate. To date, only one study has investigated whether there exists variation in ciliary beat frequency (CBF) within the sinonasal cavity. We analyzed CBF from the inferior turbinate, uncinate process, and sphenoethmoid recess in nonsinusitis patients to determine regional variability of ciliary activity within the sinonasal cavity.

Methods

Explants of sinonasal epithelium were analyzed at 37°C. Beating cilia were visualized with differential interference contrast microscopy. Images were captured using a high-speed digital camera with a sampling rate of 250 frames per second. A one-dimensional tracking algorithm analyzed individual pixel grayscale values within each frame of the video. The differences in grayscale were plotted as a time-dependent waveform, and frequency was calculated as the inverse of the peak-to-peak distance. A minimum of three areas of beating cilia were analyzed per regional sample. Statistical analysis was performed with repeated-measures analysis of variance.

Results

Complete sampling of all three sites was accomplished in 10 patients. No difference in CBF within the sinonasal cavity was identified (p < 0.05). The mean CBF for all sites in all patients was 12.6 ± 2.9 Hz, in agreement with published values.

Conclusion

This study shows no regional differences in CBF within the sinonasal cavity, supporting previous work and validating analysis of inferior turbinate cilia.

Airway hydration and COPD

Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung's mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (1) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na(+) channel (ENaC) to maintain airway hydration; (2) ciliary beating; and (3) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure.

Increased expression of the epithelial anion transporter pendrin/SLC26A4 in nasal polyps of patients with chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is a multifactorial disease of unknown cause characterized by sinonasal inflammation, increased mucus production, and defective mucociliary clearance. Expression of Pendrin, an epithelial anion transporter, is increased in asthma and chronic obstructive pulmonary disease. Pendrin increases mucus production and regulates mucociliary clearance.

OBJECTIVES

We sought to investigate the expression of pendrin and the mucus-related protein Muc5AC in sinonasal tissues of control subjects and patients with CRS and to evaluate the regulation of pendrin expression in nasal epithelial cells (NECs) in vitro.

METHODS

The expression and distribution of pendrin in sinonasal tissues was analyzed by using real-time PCR, immunoblot analysis, and immunohistochemistry. Differentiated NECs were used to study the regulation of pendrin expression.

RESULTS

Increased pendrin expression was observed in nasal polyp (NP) tissue of patients with CRS. Immunohistochemistry analysis revealed that pendrin was largely restricted to the epithelial layer. Pendrin expression significantly correlated with inflammatory cell markers, suggesting that the factors made by these cells might induce pendrin expression. Furthermore, both pendrin and periostin levels (a biomarker in asthma) correlated with IL-13 levels, suggesting that pendrin can be induced by this cytokine in sinonasal tissues. Expression of the mucus component protein Muc5AC correlated weakly with pendrin expression, indicating that pendrin might modulate mucus production in NPs. In cultured NECs pendrin expression was induced by TH2 cytokines and induced synergistically when TH2 cytokines were combined with IL-17A. Interestingly, human rhinovirus had a potentiating effect on IL-13-induced pendrin expression. Dexamethasone suppressed pendrin expression, suggesting that the therapeutic benefit of dexamethasone in asthmatic patients and those with CRS might involve regulation of pendrin expression.

CONCLUSIONS

TH2-mediated pendrin expression is increased in NPs of patients with CRS and might lead to increased inflammation, mucus production, and decreased mucociliary clearance.

Acquired cilia dysfunction in chronic rhinosinusitis

BACKGROUND

Cilia are complex and powerful cellular structures of the respiratory mucosa that play a critical role in airway defense. Respiratory epithelium is lined with cilia that perform an integrated and coordinated mechanism called mucociliary clearance. Mucociliary clearance is the process by which cilia transport the mucus blanket overlying respiratory mucosa to the gastrointestinal tract for ingestion. It is the primary means by which the airway clears pathogens, allergens, debris, and toxins. The complex structure and regulatory mechanisms that dictate the form and function of normal cilia are not entirely understood, but it is clear that ciliary dysfunction results in impaired respiratory defense.

METHODS

A literature review of the current knowledge of cilia dysfunction in chronic rhinosinsusitis was conducted.

RESULTS

Ciliary dysfunction may be primary, the result of genetic mutations resulting in abnormal cilia structure, or, more commonly, secondary, the result of environmental, infectious, or inflammatory stimuli that disrupt normal motility or coordination. Patients with chronic rhinosinusitis (CRS) have been found to have impaired mucociliary clearance. Many biochemical, environmental, and mechanical stimuli have been shown to influence ciliary beat frequency, and common microbial pathogens of respiratory mucosa such as Pseudomonas aeruginosa and Haemophilus influenzae have developed toxins that appear to interrupt normal mucociliary function. Furthermore, inflammatory mediators known to be present in patients with CRS appear to impair secondarily mucociliary clearance.

CONCLUSION

The goal of this article is to summarize the recent developments in the understanding of cilia dysfunction and mucociliary clearance in CRS.

Effect of prehydration on nasal mucociliary clearance in low relative humidity

OBJECTIVE

Nasal mucociliary clearance, which plays an important role in defending the respiratory system, tends to decrease under conditions of low relative humidity (RH). The purpose of this randomized cross-over study was to investigate the preventive effect of prehydration on nasal mucociliary clearance under low RH conditions.

METHODS

Fourteen young healthy subjects were assigned to three interventions: prehydration (6ml/kg body weight) using water (W), prehydration using a carbohydrate-electrolyte beverage (CE), and control conditions (Cont) with no prehydration. For each intervention trial, subjects sat for 4h in an environmental chamber (23°C, 10% RH). Nasal mucociliary clearance was measured by the saccharin transit time (ST). Furthermore, a dry sensation of the mucosa, urine volume, and body weight were measured at the baseline, 2h and 4h after entering the environmental chamber, respectively.

RESULTS

ST was prolonged under the Cont conditions after entering the environmental chamber. Prehydration with CE led to a significantly lower ST compared to the Cont pretreatment at 2h, whereas the W trial showed no significance difference in comparison to the Cont values.

CONCLUSION

These results suggest that prehydration with a carbohydrate-electrolyte beverage is therefore beneficial for maintaining better nasal mucociliary clearance at least for 2h under low RH conditions.

Epithelium, cilia, and mucus: their importance in chronic rhinosinusitis

Chronic rhinosinusitis is a common disease resulting from inflammation of the sinonasal mucosa. It has long been recognized that patients with chronic rhinosinusitis have impaired capacity to clear sinonasal secretions. However, the cause of this pathologic process is not well understood. In this article the components of mucociliary clearance, including cilia, mucus production, and cilia beat frequency, are reviewed and alterations of the system discussed regarding contribution to the disease process.

Effects of topical drops and sprays on mucociliary transport time and nasal air flow

CONCLUSION

This study revealed that the nasal topical drops, which could be purchased without a proper prescription, should not be used randomly and non-selectively.

OBJECTIVE

To investigate the effect of nasal drops and sprays on the nasal air flow and mucociliary transport time (MTT) in healthy volunteers with no septal deviation and no history of frequent upper respiratory infection.

SUBJECTS AND METHODS

Saline, fluticasone propionate drops and sprays, mometasone furoate, budesonide, xylometasoline chloride, fusafungine spray, Ringer's lactate and sea water were selected as the agents to be investigated. Volunteers were subdivided into two subgroups according to their rhinomanometric scores: group 1 consisted of subjects with nasal respiration > or =500 ml at 150 daPa and group 2 consisted of those with nasal air flow <500 ml.

RESULTS

No statistically significant difference was found among the effects of these agents on MTT in group 1. In group 2, xylometasoline chloride, fluticasone propionate spray and sea water sprays prolonged the MTT. When the rhinomanometric scores at 150 daPa were assessed, use of xylometasoline chloride, fluticasone propionate drops, budesonide, fusafungine, sea water and Ringer's lactate were found to diminish the nasal air flow with respect to normal values in group 1. In group 2, no significant difference was noticed between normal values and values acquired after use of nasal drops. Comparing the same agents, we did not find a significant difference between groups 1 and 2 regarding MTT and nasal air flow.

In Vivo Effects of Citric Acid/Zwitterionic Surfactant Cleansing Solution on Rabbit Sinus Mucosa

Background

Chronic rhinosinusitis that is refractory to medical or surgical intervention may involve a particularly resistant form of infection known as a bacterial biofilm that is recalcitrant to antibiotics secondary to physical barrier characteristics. Recently, a novel sinus cleansing solution, citric acid/zwitterionic surfactant (CAZS) was shown to be extremely effective in disrupting biofilms in vitro. The purpose of this study was to determine the effects of CAZS on sinonasal epithelium in vivo compared with normal saline.

Methods

Indwelling catheters were placed into the right maxillary sinus of New Zealand white rabbits. CAZS solution or normal saline (10 mL) was instilled at a rate of 20 mL/minute into the sinus followed by aspiration. Rabbits were killed 1, 3, and 6 days after treatment. Mucosa from both maxillary sinuses was harvested and evaluated for physiological activity (ciliary beating) as well as morphological integrity of the epithelium by scanning electron microscopy.

Results

One day after treatment, beating cilia was evident with morphological analysis shown intact epithelium with 80–85% denudation of cilia compared with saline. Three days after treatment, ciliary activity was again noted with morphological evidence of persistent denuded cilia. By day 6 after treatment, the epithelium had regenerated cilia over the apical surface. Throughout the recovery period beating cilia was evident in CAZS-treated sinuses.

Conclusion

This study shows that although CAZS acutely denudes respiratory cilia, the remaining cilia are active. Additionally, the epithelial barrier appears intact with active ciliogenesis, and reciliation of the mucosal surface occurring 6 days after treatment.

Impact of isotonic and hypertonic saline solutions on mucociliary activity in various nasal pathologies: clinical study

OBJECTIVE

To investigate the impact of nasal irrigation with isotonic or hypertonic sodium chloride solution on mucociliary clearance time in patients with allergic rhinitis, acute sinusitis and chronic sinusitis.

PATIENTS AND METHODS

Mucociliary clearance time was measured using the saccharine clearance test on 132 adults before and after 10 days' application of intranasal isotonic or hypertonic saline. Patient numbers were as follows: controls, 45; allergic rhinitis, 21; acute sinusitis, 24; and chronic sinusitis, 42. The results before and after irrigation were compared using the Wilcoxon t-test.

RESULTS

Before application of saline solutions, mucociliary clearance times in the three patient treatment groups were found to be significantly delayed, compared with the control group. Irrigation with hypertonic saline restored impaired mucociliary clearance in chronic sinusitis patients (p < 0.05), while isotonic saline improved mucociliary clearance times significantly in allergic rhinitis and acute sinusitis patients (p < 0.05).

CONCLUSION

Nasal irrigation with isotonic or hypertonic saline can improve mucociliary clearance time in various nasal pathologies. However, these solutions should be selectively prescribed rather than used based on anecdotal evidence. Further studies should be conducted to develop a protocol for standardised use of saline solution irrigation in various nasal pathologies.

Mucociliary clearance – a critical upper airway host defense mechanism and methods of assessment

PURPOSE OF REVIEW

Mucociliary clearance is a critical host defense mechanism of the airways. Effective mucociliary clearance requires appropriate mucus production and coordinated ciliary activity. The important role of these two components is best demonstrated in disorders such as primary ciliary dyskinesia and cystic fibrosis, both of which lead to lifelong recurrent respiratory tract infections. We review the methods used to analyze mucociliary clearance.

RECENT FINDINGS

Utilization of microdialysis probes has improved temporal resolution of mucociliary clearance in murine airways, availing many genetic mouse models to critical mucociliary clearance analysis, while improved fixation technique for transmission electron microscopy has allowed for detailed resolution of the airway surface liquid. High-speed digital video analysis has improved quantification of ciliary beat frequency while advancements in air-liquid interface culturing techniques have generated in-vitro models to investigate mucociliary clearance.

SUMMARY

Advancements in techniques for analysis of mucociliary clearance have improved our understanding of the interaction between the respiratory epithelium and the airway surface liquid, resulting in the ability to study pathologic processes involving mucociliary clearance in great detail.

Altered sinonasal ciliary dynamics in chronic rhinosinusitis

BACKGROUND

Although multiple etiologies contribute to the development of rhinosinusitis, a common pathophysiological sequelae is ineffective sinonasal mucociliary clearance, resulting in stasis of sinonasal secretions, with subsequent infection, and persistent inflammation. The respiratory cilia beat continually at a basal rate, while during times of stress, such as exercise or infection, ciliary beat frequency (CBF) increases, accelerating mucus clearance. Previous investigations have led to conflicting results with some authors reporting decreased CBF while others have found normal values of CBF in patients with chronic rhinosinusitis (CRS). Additionally, these studies have only analyzed basal CBF. The goal of this study was to compare the basal as well as the stimulated sinonasal CBF in patients with CRS versus controls.

METHODS

A dual temperature controlled perfusion chamber, differential interference contrast microscopy, and high-speed digital video were used to analyze both basal and adenosine triphosphate (100 microM)-stimulated CBF in human sinonasal mucosal explants.

RESULTS

Although no difference in basal CBF was detected between control and CRS patients, a marked difference in stimulated CBF was noted. Exogenously applied adenosine triphosphate resulted in a 50-70% increase of CBF in control tissue with a minimally observed CBF increase in explants from CRS patients.

CONCLUSION

Dynamic regulation of respiratory ciliary activity is critical for the respiratory epithelium to adapt to varying environmental situations. Thus, diminished or absent adaptation could predispose the sinonasal cavity to accumulation of inhaled infectious and noxious particulate matter resulting in infection/inflammation. Our findings suggest that CRS patients have decreased sinonasal ciliary adaptation to environmental stimuli.

Composition, morphology and mechanics of hagfish slime

Hagfish slime consists of mucins and protein threads that are released from slime glands and mix with seawater to produce an ephemeral material with intriguing physical properties. We recently characterized the mechanics of the slime's fibrous component, and here we report the first mechanical properties of the mucin component and the slime as a whole. Our results suggest that hagfishes can produce remarkable quantities of the slime because it is almost three orders of magnitude more dilute than typical mucus secretions. Mechanical experiments using whole slime produced in vitro demonstrate that the slime threads dominate the slime's material properties and impart elasticity. Mucins impart viscosity at the strain rates tested and are important for rapid deployment of the slime. We also found that slime threads are tapered at both ends, which suggested to us that hagfish slime might best be modeled as a discontinuous fibre-reinforced composite. Our measurements demonstrate that the mucins are not capable of providing shear linkage between threads, but this is not necessary because the threads are long enough to span an entire slime mass. Our findings suggest that hagfish slime consists mainly of bulk seawater entrained between mucin-coated threads, and in this way functions more like a fine sieve than coherent mucus. These results are consistent with the hypothesis that the slime has evolved as a defense against gill-breathing predators.

Mucoactive medications and airway disease

Airway mucociliary clearance depends on the properties and volume of secreted mucus, ciliary function and mucociliary interactions. In chronic airway diseases, mucus viscoelasticity is higher than the optimal values for mucociliary clearance. The mucous glycoproteins (MGs) are produced by goblet and submucosal gland cells and are the most important determinant of the viscoelasticity of normal respiratory mucus, although with chronic infection and inflammation neutrophil-derived DNA and F-actin assume an important role. The quantities and structures of MGs mainly determine the rheological properties of mucus. Mucolytic agents, such as the thiols with free sulphydryl groups (classic mucolytics) and proteolytic enzymes (peptide mucolytics) change the conformation of mucus and lead to the reduction of viscoelasticity. Mucoregulatory medications such as glucocorticoids and macrolide antibiotics may decrease the hypersecretion of MGs.

The nose and paranasal sinuses physiology and anatomy

The paranasal sinuses and nose are much more than two cavities behind a projection on the centre of the face. They humidify, filter, warm, and sense what we breathe. The anatomy and physiology interact forming a dynamic system. The anatomy, airflow, nasal resistance, its turbulence, the nasal cycle - a process by which the turbinates or cushions lining the nose alternatively swell and congest from side to side, can all potentially influence the nasal delivery of drugs. Along with these factors mucus rheology and mucociliary clearance influence the removal of substances delivered to the nose. The health of the nose and its immunological response to what is inhaled, be it pollutants, allergens, drugs or vaccines, all need to be considered. It is a fascinating sensor for the body, not only detecting the potentially harmful substances such as smoke, but its psychosexual aspects have far reaching implications and the olfactory pathway has potential as a pathway for the delivery of drugs.

Hypertonic saline decreases ciliary movement in human nasal epithelium in vitro

Various saline solution formulae are frequently used in patients with rhinosinusitis. Osmolarity affects ciliary beat frequency (CBF); however, little is known about the effects of saline solutions on ciliary activity of nasal epithelial cells. The aim of this study was to assess whether CBF of normal turbinate mucosa is affected by hypertonic, isotonic, or hypotonic saline solution in vitro and whether histologic changes are associated with the alteration of ciliary movement. We assessed variations of CBF after exposure to 0.06%, 0.12%, 0.9%, 3.0%, or 7.0% saline solutions and histologic changes were examined by transmission electron microscopy. Isotonic and hypotonic solutions produced no ciliary slowing; however, ciliostasis was observed within a few minutes in 3.0% or 7.0% solution. The histologic changes demonstrated that the ciliary slowing might be attributed to epithelial damage by fluid transport toward the surrounding medium. In conclusion, hypertonic saline solutions decrease CBF and disrupt nasal epithelial cells in vitro.

Physiologic and hypertonic saline solutions impair ciliary activity in vitro

OBJECTIVE/HYPOTHESIS

Physiologic saline (NaCl 0.9%) is commonly used in treating acute and chronic rhinosinusitis. Moreover, physiologic saline is used as a control medium, vehicle, or solvent in studies on ciliary beat frequency (CBF). Hypertonic saline (NaCl 7% and 14.4%) has been applied in attempts to enhance mucociliary transport in patients with cystic fibrosis or asthma and in healthy subjects. Therefore the objective of this study is to document in vitro effects of saline solutions in different concentrations on CBF.

STUDY DESIGN

Experimental, in vitro.

METHODS

The effects on CBF of cryopreserved mucosa of the sphenoidal sinus was measured by a photoelectrical method. Initial frequencies, measured in Locke-Ringer's solution (LR), were compared with CBF after exposure to NaCl in concentrations of 0.9%, 7.0%, and 14.4% (w/v).

RESULTS

NaCl 0.9% has a moderately negative effect on CBF. The 7% solution leads to a complete ciliostasis within 5 minutes, although this effect turns out to be reversible after rinsing with LR. A hypertonic solution of 14.4% has an irreversible ciliostatic effect.

CONCLUSION

LR is an isotonic solution that has no effect on CBF. Therefore it is probable that this solution is more appropriate than saline for nasal irrigation and nebulization or antral lavage. Moreover, the results of this study suggest that mucolytic effects induced by hyperosmolarity should be attained preferably with hypertonic saline 7% in patients with cystic fibrosis or asthma. At this concentration, the ciliostatic effect is reversible, whereas irreversible changes are to be expected at higher concentrations.

Current concepts in the management of paediatric rhinosinusitis

It is well recognized that adenoid hypertrophy and allergic rhinitis are common in children and that recurrent upper respiratory tract infections are a fact of life. The main causes of symptoms associated with rhinosinusitis in children are rhinorrhoea, nasal obstruction, mouth breathing, hyponasal speech and snoring. Most children grow out of adenoid hypertrophy and recurrent colds by the age of eight to 10 and this means that the main treatment strategy should therefore be conservative and not surgical. An explanation to anxious parents, simple non-invasive measures such as teaching nose-blowing, the use of saline sprays or a trial of allergen avoidance and age-appropriate topical nasal anti-inflammatory sprays should be tried before surgery is even contemplated. Because repeated infections are so common, antibiotics given for chronic nasal discharge often have only short-lived effects. Rhinosinusitis in children is not a surgical disease and 'watchful waiting' is advised. Any treatment should first of all be safe, as even without any intervention the problem usually resolves with time. It is likely that growth and maturation of the immunological response to pathogens play a major role in resolution of the disease. There are few exceptions to this principle: nasal polyps (indicating possible cystic fibrosis), and periorbital cellulitis where an assessment of vision, parenteral antibiotics, and if there is concern about the possibility of a subperiosteal abscess, computerized tomography (CT) and drainage of any pus is indicated.

Nasal mucociliary clearance of chronic sinusitis in relation to rheological properties of nasal mucus

The role of the viscosity (eta') and elasticity (G') of nasal mucus in nasal mucociliary clearance (MCC) in chronic sinusitis (CS) was studied. The nasal mucus was collected from 17 patients with CS, and both eta' and G' were determined by an oscillating sphere magnetic rheometer. Following the nasal mucus collection, nasal MCC was measured by a radioisotope method in the patients and 22 normal subjects. Nasal MCC in the patients was significantly reduced compared with that in the normal subjects (p < .05). No significant correlation was noted between nasal MCC and eta', or between nasal MCC and G'. The results suggest that factors other than eta' and G' of nasal mucus may control nasal MCC in CS.

Mucociliary clearance and buffered hypertonic saline solution

Nasal irrigations have been used for centuries without any scientific data to determine efficacy. For 10 years, the senior author has used buffered hypertonic saline nasal irrigation for patients with acute/chronic sinusitis and for those having undergone sinus surgery. A simple study was undertaken using volunteers without any significant sinonasal disease. Patients served as their own control using a saccharin clearance test before any nasal irrigation was used. Patients then used one of two solutions to irrigate their nose-buffered normal saline or buffered hypertonic saline-and were then retested. On a separate day, the control test was repeated, followed by irrigation with the alternate solution and a second saccharin clearance test. The outcome showed buffered hypertonic saline nasal irrigation to improve mucociliary transit times of saccharin, while buffered normal saline had no such effect.

Sinusitis in childhood

There is much to be learned about sinusitis in children. The appropriate choice and timing of diagnostic tests, correct type and duration of antibiotic treatment, role of allergy management and adjuvant drugs, and indications for and limits of endoscopic sinus surgery remain to be defined. Technological advances have been introduced and accepted as standard with little validation. Well-thought-out, controlled studies of diagnostic and treatment modalities are needed to address these issues and to better understand the function of the sinuses in health and illness.

Effect of atropine on nasal mucociliary clearance

To investigate the effect of atropine on mucociliary function, nasal mucociliary clearance was measured with two methods in eight healthy men before and after subcutaneous injection of atropine sulphate. The movement of two different tracers placed 1.5 cm posterior to the inferior turbinate tip was measured. The transport rate of a resin particle tagged with 99mTc was measured. The clearance of 10 microliters saline labelled with 99mTc was monitored and the clearance rate calculated. Whereas atropine lowered the resin particle transport rate, the saline method did not reveal any difference in clearance rate after injection of atropine. Since the former method measures the transport of particles in the gel phase (the outer mucous layer) and the latter measures the clearance of both gel and sol (periciliary fluid) layers, it is postulated that the slowing of mucociliary transport by atropine is due to alterations in the gel layer.

The effect of submucous resection of the nasal septum on mucociliary transport and nasal airway

This paper reports changes in ciliary function following submucous resection of the nasal septum in 36 adult patients assessed by measuring mucociliary clearance time with a saccharine particle using the method described by Andersen et al. The alterations in mucociliary clearance time were compared with active anterior rhinomanometry. Following surgery, changes in symptoms of nasal obstruction as recorded by questionnaire were largely consistent with changes in mucociliary function and to a lesser extent with rhinomanometry. It is suggested that patients with a mucociliary clearance time of less than 10 min in the more blocked nostril may be less likely to benefit from surgery.

The effect of an orally administered proteolytic enzyme on the elasticity and viscosity of nasal mucus

We have evaluated the effect of serratiopeptidase (SER), a proteolytic enzyme, on the elasticity and viscosity of the nasal mucus in adult patients with chronic sinusitis. SER was administered in a dose of 30 mg/day orally for 4 weeks. Nasal mucus was collected from the nasal cavities of each patient before (week 0) and 4 weeks after the start of the medication (week 4). The storage modulus (G') and the dynamic viscosity (eta') of each specimen of nasal mucus were determined by an oscillating sphere magnetic rheometer at frequencies of 0.5, 1, 5, 10 and 20 Hz at a constant temperature of 25 degrees C. The dynamic viscosity (eta') of the mucus at week 4 was significantly lower than that at week 0 (at frequencies of 5, 10 and 20 Hz). No significant differences were observed in the storage modulus (G') between the mucus at week 0 and week 4. SER reduced the viscosity but not the elasticity of the nasal mucus. These findings are discussed in relation to mucociliary clearance.

Rheological properties of middle ear effusions from children with otitis media with effusion

Freshly harvested middle ear effusions (MEE) were collected from children with otitis media with effusion. Both elasticity (G') and viscosity (eta') of the MEE were determined by an oscillating sphere magnetic rheometer and compared with transportability of the MEE on mucus-depleted frog palates. A maximum value of transport was obtained at G' of about 20 dyne/cm2 (at 1 Hz), and below this value there was a significant positive correlation between the transport rate and log G'. Above 20 dyne/cm2, the negative correlation between the transport rate and log G' was significant. This shows there is a sharp increase in transport with increase in G' up to 20 dyne/cm2, and at the higher value of G' there is a slow decrease in transport with increasing G'. A similar significant correlation between the transport rate and log eta' was observed.

Possible mechanisms of reduction of nasal mucociliary clearance in chronic sinusitis

Nasal mucus was collected from 38 patients with chronic sinusitis. Following this collection, nasal mucociliary clearance (ST) was measured by the saccharin granule technique. Nasal mucus was used for in vitro frog palate clearance studies and then compared with the in vivo ST. The mucociliary transport rate of nasal mucus on mucus-depleted frog palate (MTR on frog palate) was 5.93 +/- 1.04 mm/min in the patients whose ST was within normal range (group A), and was 5.54 +/- 1.94 mm/min in the patients whose ST was above the normal range (group B). Significant differences were not observed in MTR on frog palate between groups A and B and no significant correlation was noted between ST and MTR. These results suggest that factors other than the rheological properties of nasal mucus control nasal mucociliary clearance in patients with chronic sinusitis.

Reversibility of reduced mucociliary clearance in chronic sinusitis

Nasal mucociliary clearance was measured before and after treatment in patients with chronic sinusitis. Nasal mucociliary transit time before the study was greater than 36 min in 8 out of 14 patients who were treated with S-carboxymethylcysteine, and in 9 out of 22 patients who were treated by repeated antral lavage. The nasal mucociliary clearance was significantly improved by both treatment regimens. This may indicate that the malfunction of the nasal mucociliary system is not the cause of chronic sinusitis but an effect of chronic inflammation of the respiratory mucosa.

Rheological properties of middle ear effusion and their role on mucociliary clearance

The viscoelastic properties of freshly harvested middle ear effusion (MEE) from children were determined by an oscillating sphere magnetic rheometer and compared with transportability of MEE on mucus-depleted frog palate. The elastic modulus (G') at 1 Hz of MEE from 43 untreated ear was ranged from 1.9 to 1,790 dyn/cm2 and the mean value was 28.4 dyn/cm2. The dynamic viscosity (eta') at 1 Hz of the same samples was ranged from 0.2 to 146 poise with the mean value of 3.4 poise. A maximum value of transport was obtained at G' of about 20 dyn/cm2, and below this value there was a significant positive correlation between the transport rate and log G'. Above 20 dyn/cm2, the negative correlation between the transport rate and log G' was significant. A similar significant correlation between the transport rate and log eta' was observed.

Abnormal nasal mucociliary clearance in patients with rhinitis and its relationship to concomitant chest disease

Nasal mucociliary clearance was measured using a saccharin technique in 172 patients with perennial rhinitis (76 also had asthma) and in 121 patients with chronic infected rhinosinusitis (40 had asthma, 35 had bronchiectasis). All patient groups had significantly longer mean nasal mucociliary clearance times than that of a group of healthy subjects. Grossly prolonged clearance (greater than 60 minutes) occurred in significantly more patients with the clinical syndrome of chronic infected rhinosinusitis and bronchiectasis than in the syndromes of chronic infected rhinosinusitis with or without asthma, and perennial rhinitis with or without asthma. The abnormal clearance was shown not to be due to an intrinsic ciliary defect by in vitro examination of nasal cilia but probably to be due to a combination of mucus and ciliary factors in vivo.