Mucociliary transport and its assessment: a review

Naso-mucociliary Clearance Time among Patients with Chronic Rhinosinusitis in Ilorin, North-central Nigeria

CONTEXT

The mucociliary clearance system is an important component in the prevention of chronic inflammation of the nasal and paranasal sinus.

AIM

The study aims to establish the normal values of mucociliary clearance in our region and to study the variation in mucociliary activity in patients with chronic rhinosinusitis in Ilorin, North-central Nigeria.

SETTINGS AND DESIGN

This was a prospective, cross-sectional study using consecutive consenting participants in both the control and study groups carried out at both family medicine and otorhinolaryngology clinics among patients attending the clinics.

SUBJECTS AND METHODS

After ethical approval was sought, informed consent was obtained from patients, a modified version of the validated health questionnaire was filled, semi-structured questionnaires were also filled after which patient undergo anterior rhinoscopy, nasal patency test and spirometry was done. The saccharine test has been used to measure nasal-mucociliary clearance time in the past.

STATISTICAL ANALYSIS

All information were entered into SPSS version 20 and analysed descriptively, and results were presented in tables and figures.

RESULTS

Consecutive consenting 125 patients with rhinosinusitis (study group) and those without rhinosinusitis (control group) underwent naso-mucociliary clearance test. There were 34 males and 91 females with a male:female ratio of 1:2.6 among the study group and 55 males and 70 females with a male:female ratio of 1:1.3 for the control group. The age range was from 18 to 68 years with 18-40 years constituting the modal age group. The mean age for the studied group was 35.7 years while that of the control group was 33.1 years. The mean naso-mucociliary clearance time among the study group was 35.1 min standard deviation (SD = 12.32 ± 1.63), while among the control group, it was 14.8 min (SD = 5.59 ± 0.43).

CONCLUSION

Compared to the control group, there was a roughly 200% prolonged increase in the duration of naso-mucociliary clearance time among patients with rhinosinusitis. There was also a positive correlation with increasing age. Future studies comparing the pre-operative and post-operative treatment of rhinosinusitis will contribute to knowledge.

Enhancing Mucoadhesive Properties of Gelatin through Chemical Modification with Unsaturated Anhydrides

Gelatin is a water-soluble natural polyampholyte with poor mucoadhesive properties. It has traditionally been used as a major ingredient in many pharmaceuticals, including soft and hard capsules, suppositories, tissue engineering, and regenerative medicine. The mucoadhesive properties of gelatin can be improved by modifying it through conjugation with specific adhesive unsaturated groups. In this study, gelatin was modified by reacting with crotonic, itaconic, and methacrylic anhydrides in varying molar ratios to yield crotonoylated-, itaconoylated-, and methacryloylated gelatins (abbreviated as Gel-CA, Gel-IA, and Gel-MA, respectively). The successful synthesis was confirmed using 1H NMR, FTIR spectroscopies, and colorimetric TNBSA assay. The effect of chemical modification on the isoelectric point was studied through viscosity and electrophoretic mobility measurements. The evolution of the storage (G') and loss (G'') moduli was employed to determine thermoreversible gelation points of modified and unmodified gelatins. The safety of modified gelatin derivatives was assessed with an in vivo slug mucosal irritation test (SMIT) and an in vitro MTT assay utilizing human pulmonary fibroblasts cell line. Two different model dosage forms, such as physical gels and spray-dried microparticles, were prepared and their mucoadhesive properties were evaluated using a flow-through technique with fluorescent detection and a tensile test with ex vivo porcine vaginal tissues and sheep nasal mucosa. Gelatins modified with unsaturated groups exhibited superior mucoadhesive properties compared to native gelatin. The enhanced ability of gelatin modified with these unsaturated functional groups is due to the formation of covalent bonds with cysteine-rich subdomains present in the mucin via thiol-ene click Michael-type addition reactions occurring under physiologically relevant conditions.

Optimization of Pramipexole-Loaded In Situ Thermosensitive Intranasal Gel for Parkinson's Disease

The objective of the present work was to develop and optimize an intranasal in situ gel of Pramipexole dihydrochloride for enhanced drug delivery, better patient acceptability, and possible proper treatment of Parkinson's disease. Preliminary studies were performed to select formulation components and identify key variables affecting the formulation. The optimization of the in situ gelling system of Pramipexole dihydrochloride was achieved by applying 32 full factorial design using Design-Expert® software (Stat-Ease 9.0.6 version) and taking concentrations of Poloxamer 407 (X1) and HPMC K4M (X2) as independent variables. The gelling temperature, gel strength, and percentage of drug diffused after 8 h were taken as dependent variables. The software provided an optimized formulation, with 16.50% of X1 and 0.2% of X2 with the highest desirability. An in vivo drug retention time study was performed for the optimized formulation in Wistar rats. The results of the optimization process demonstrated that the selected gel formulation exhibited desirable characteristics, including gelation near body temperature, good gel strength, suitable viscosity, and sustained drug release. The optimized formulation displayed significantly higher drug retention, lasting about 5 h, versus the plain poloxamer gel formulation. Hence, it was concluded that the optimized formulation will remain affixed at the site of application for a significant time after intranasal administration and consequently sustain the release of the drug. The optimized formulation was found to be stable during the stability studies. The developed dosage form may improve patient compliance, enhance nasal drug residence, and offer sustained drug release. However, further clinical studies are necessary to validate these findings.

The prescription design and key properties of nasal gel for CNS drug delivery: A review

Central nervous system (CNS) diseases are among the major health problems. However, blood-brain barrier (BBB) makes traditional oral and intravenous delivery of CNS drugs inefficient. The unique direct connection between the nose and the brain makes nasal administration a great potential advantage in CNS drugs delivery. However, nasal mucociliary clearance (NMCC) limits the development of drug delivery systems. Appropriate nasal gel viscosity alleviates NMCC to a certain extent, gels based on gellan gum, chitosan, carbomer, cellulose and poloxamer have been widely reported. However, nasal gel formulation design and key properties for alleviating NMCC have not been clearly discussed. This article summarizes gel formulations of different polymers in existing nasal gel systems, and attempts to provide a basis for researchers to conduct in-depth research on the key characteristics of gel matrix against NMCC.

The effect of autosomal dominant polycystic kidney disease on mucociliary clearance

PURPOSE

Autosomal dominant polycystic kidney disease (ADPKD) is a renal disease with genetic transmisson. Mutations in the PKD1 and PKD2 genes, which encode integral membrane proteins of the cilia of primary renal tubule epithelial cells, are seen in ADPKD. The aim of this study was to evaluate the sinonasal epithelium, which is epithelium with cilia, by measuring the nasal mucociliary clearance time, and to investigate the effect of ADPKD on nasal mucociliary clearance.

METHODS

The study included 34 patients, selected from patients followed up in the Nephrology Clinic, and 34 age and gender-matched control group subjects. The nasal mucociliary clearance time (NMCT) was measured with the saccharin test.

RESULTS

The mean age of the study subjects was 47.15 ± 14.16 years in the patient group and 47.65 ± 13.85 years in the control group. The eGFR rate was determined as mean 72.06 ± 34.26 mL/min in the patient group and 99.79 ± 17.22 mL/min in the control group (p < 0.001). The NMCT was determined to be statistically significantly longer in the patient group (903.6 ± 487.8 s) than in the control group (580 ± 259 s) (p = 0.006).

CONCLUSIONS

The study results showed that the NMCT was statistically significantly longer in patients with ADPKD compared to the control group, but in the linear regression analysis results, no correlation was determined between eGFR and NMCT.

Numerical investigation of mucociliary clearance using power law and thixotropic mucus layers under discrete and continuous cilia motion

Mucus layer movement inside the airway system is an important phenomenon as the first defensive mechanism against pathogens. This research deals with the mucus velocity variations inside the nasal cavity using two different power law and thixotropic mucus layers. The cilia movement is replaced with four cyclic velocity profiles at the lower boundary of the mucus layer, while the upper boundary is exposed to the free-slip condition. The effects of boundary conditions and different fluid parameters are evaluated on the mucus flow. Furthermore, the replacement of power law and thixotropic mucus layers with a high viscous Newtonian mucus is examined under the free-slip condition at the mucus upper boundary. The adaptation rate is used as the criteria for replacing fluids instead of each other. The results show the mucus flow has enough time to adjust the changes from the lower boundary and the recovery stroke does not affect the mucus velocity in the effective stroke. Moreover, it is observed that the mucus flow variations are the same under the influence of recovery, breakdown, and breakdown exponent parameters. However, the effects of the exponent parameter on the mucus flow are more than the other two parameters in the recovery stroke. It is concluded that the assumption for replacing the power law mucus with a high viscous Newtonian one is acceptable. However, this assumption leads to the maximum error of 98.5% for thixotropic mucus in the recovery stroke.

Effects of indoor summer dehumidification and winter humidification on the physiological and subjective responses of the elderly

The purpose of this study was to clarify the physiological and subjective responses of the elderly to dehumidification in a humid summer and humidification in a dry winter compared with the young. Sixteen elderly and sixteen young subjects participated in the dehumidification experiment (DE) and 13 elderly and 15 young subjects participated in the humidification experiment (HE). The air temperature in the climate chamber was set at 28 °C, and humidity was decreased from 70% relative humidity (RH) to 50% RH for 90 min in the DE. The air temperature was set at 25 °C, and the humidity was increased from 30% RH to 50% RH for 90 min in the HE. Skin temperature, body weight, transepidermal water loss (TEWL), skin hydration state, saccharin clearance time (SCT), and blinking frequency were measured during exposure; whereby we evaluated humidity sensation, thermal sensation, and thermal comfort. Dehumidification caused a significant decrease in skin temperature in both age groups owing to greater insensible perspiration. Humidification significantly shortened the SCT in both age groups. TEWL increased significantly in the DE and decreased in the HE. For the physiological responses (skin temperature, skin physiology, SCT, and blinking frequency) to dehumidification and humidification, no distinct differences between the age groups were observed. However, subjective responses suggested that the elderly were less sensitive to humidity differences than the young in both the DE and HE.

Effects of continuous and discrete boundary conditions on the movement of upper-convected maxwell and Newtonian mucus layers in coughing and sneezing

Mucociliary clearance is an important phenomenon inside the respiratory system as a first defensive mechanism against pathogens. Therefore, any assumption considered for the mucociliary clearance and affects its functionality must be validated. The present research deals with the effects of boundary conditions on the movement of upper-convected Maxwell and high viscosity Newtonian mucus layers, numerically. Furthermore, the validity of replacing the viscoelastic mucus layer with a high viscosity Newtonian layer is evaluated. The airway surface liquid layer is considered a two-layer model including non-Newtonian mucus and Newtonian periciliary layers. Four cyclic boundary conditions are imposed at the mucus-periciliary interface as the cilia movement to obtain variations of mucociliary clearance. The upper boundary of the mucus layer is also exposed to different shear stress levels including free slip, cough, and sneeze conditions. By investigation of velocity variations inside mucus and periciliary layers, it is concluded the differences between viscoelastic and Newtonian mucus are not negligible. The maximum velocity differences between the two fluids are more than 52% and 215% during cough and sneeze, respectively. The results show there is a high order of dependency between the relaxation time and the imposed boundary conditions at the mucus-periciliary interface that leads to the invalidation of replacing two fluids with each other. Moreover, the results show substituting the viscoelastic mucus with a high viscosity Newtonian one depends on the mucus-periciliary interface boundary condition. If an independent time-varying boundary condition is used, the substitution leads to an error less than 7% under different shear stress levels. However, time-varying boundary condition shows 38% and 88% differences between high viscosity Newtonian and viscoelastic mucus layers. Furthermore, neglecting the recovery stroke leads to a velocity underestimation up to 50% by substituting viscoelastic mucus with a high viscosity Newtonian one. Therefore, replacing the viscoelastic mucus with a high viscosity Newtonian one is not acceptable for numerical simulations.

The relationship between Covid-19 and mucociliary clearance

BACKGROUND

The effect of Covid-19 infection on nasal mucociliary clearance (MCC) is unknown.

AIMS/OBJECTIVES

The aim of this study is to investigate the relationship between Covid-19 and nasal MCC in terms of smoking, Covid-19 symptoms and treatment.

METHODS

Thirty-six patients who were hospitalized in the pandemic ward due to Covid-19 and 36 volunteers (Covid-19 negative test result) who presented to the otolaryngology outpatient clinic with non-nasal symptoms were included in this study. The Saccharin test was performed in both groups to evaluate nasal MCC.

RESULTS

The patients and control groups were not significantly different in terms of age and gender. The nasal MCC time was significantly higher in the patient group compared to the control group (19.18 ± 10.84 min and 13.78 ± 8.18 min, p = .003).

CONCLUSIONS AND SIGNIFICANCE

In this study, we found that Covid-19 prolonged nasal MCC time regardless of age. We suggest that corticosteroids should be included in the treatment of Covid-19, both with its symptom reduction and its positive effect on MCC duration.

Intranasal Zolmitriptan-Loaded Bilosomes with Extended Nasal Mucociliary Transit Time for Direct Nose to Brain Delivery

This study aimed at delivering intranasal zolmitriptan directly to the brain through preparation of bilosomes incorporated into a mucoadhesive in situ gel with extended nasal mucociliary transit time. Zolmitriptan-loaded bilosomes were constructed through a thin film hydration method applying Box-Behnken design. The independent variables were amount of sodium deoxycholate and the amount and molar ratio of cholesterol/Span® 40 mixture. Bilosomes were assessed for their entrapment efficiency, particle size and in vitro release. The optimal bilosomes were loaded into mucoadhesive in situ gel consisting of poloxamer 407 and hydroxypropyl methylcellulose. The systemic and brain kinetics of Zolmitriptan were evaluated in rats by comparing intranasal administration of prepared gel to an IV solution. Statistical analysis suggested an optimized bilosomal formulation composition of sodium deoxycholate (5 mg) with an amount and molar ratio of cholesterol/Span® 40 mixture of 255 mg and 1:7.7, respectively. The mucoadhesive in situ gel containing bilosomal formulation had a sol-gel temperature of 34.03 °C and an extended mucociliary transit time of 22.36 min. The gelling system possessed enhanced brain bioavailability compared to bilosomal dispersion (1176.98 vs. 835.77%, respectively) following intranasal administration. The gel revealed successful brain targeting with improved drug targeting efficiency and direct transport percentage indices. The intranasal delivery of mucoadhesive in situ gel containing zolmitriptan-loaded bilosomes offered direct nose-to-brain drug targeting with enhanced brain bioavailability.

In Vitro Ciliotoxicity and Cytotoxicity Testing of Repeated Chronic Exposure to Topical Nasal Formulations for Safety Studies

Certain active drugs and excipients of nasal formulations may impair ciliary function and mucociliary clearance. The ciliary beat frequency (CBF) is a key parameter for determining mucociliary clearance rate, and in vitro assessments of CBF have proven to be accurate and reproducible. Since topical nasal formulations are applied with repeated doses, it is essential to elucidate their chronic, as opposed to acute, effect on mucociliary clearance and nasal mucosa. The aim of this study was to assess for the first time the ciliotoxicity and cytotoxicity of nasal sprays intended for chronic treatment (with repeated doses) using a previously designed set-up for CBF measurements. For 2 weeks, the 3D nasal MucilAir™ in vitro models were treated daily with undiluted or clinically relevant doses of mometasone nasal spray, placebo nasal spray, culture medium, or they were untreated. We demonstrated a dose-dependent and time-dependent (cumulative) effect of the nasal sprays on ciliary activity and cytotoxicity using CBF measurements and ultrastructural analysis, respectively. Our results indicate that repeated administration of clinically relevant doses of mometasone nasal spray is safe for in vivo use, which is in good agreement with a previous clinical study. Overall, our study suggests that such in vitro assays have great potential for topical nasal drug screening.

Effects of rapid maxillary expansion or alternating rapid maxillary expansion and constriction on nasal mucociliary clearance : A randomized clinical trial

PURPOSE

This parallel trial aimed to evaluate the changes in nasal mucociliary clearance (MCC) after a rapid maxillary expansion (RME) protocol or an alternating rapid maxillary expansion and constriction (Alt-RAMEC) protocol in orthodontic patients.

METHODS

This trial included 36 patients with a mean age of 14.38 years, with a narrow maxillary arch, bilateral posterior crossbite, no narrowing of the mandibular arch, no previous orthodontic treatment, and no nasal or systemic disease. Patients were randomly distributed into two groups (n = 18 each)-one group was treated with the RME protocol and the other group was treated with the Alt-RAMEC protocol. MCC was evaluated using the saccharine transit time (STT) test, which was measured for each individual before expansion (T0), after expansion (T1), and after a 4-month retention phase (T2). The study was single blinded, and blinding was applied only to the outcome assessor. The primary objective was to evaluate the effect of the Alt-RAMEC and RME protocols on MCC. The secondary objective was to determine the relationship between age, sex, and MCC. The χ ² test and independent samples t‑test were used to evaluate the data.

RESULTS

The STT decreased after expansion and retention in the RME group. In the Alt-RAMEC group, the STT decreased after expansion and slightly increased after retention. When the RME and Alt-RAMEC groups were compared, the STT showed a significant difference after expansion and retention (p < 0.05). No significant relationship was observed between age and sex and STT (p > 0.05).

CONCLUSION

This study demonstrated that the Alt-RAMEC protocol improved MCC and had a positive effect on nasal physiology by increasing the nasal volume more than that achieved by RME.

Assessment of mucociliary clearance as an indicator of nasal function in patients with COVID-19: a cross-sectional study

PURPOSE

We assessed the effects of COVID-19 infection on nasal mucociliary activity.

METHODS

The study was conducted in the pandemic wards of Adiyaman University Training and Research Hospital during April and May 2020. All patients admitted to the COVID-19 pandemic wards during the study period were invited to participate in the study. The study included 40 adults who agreed to participate and underwent a mucociliary clearance test successfully. The primary outcome was mucociliary clearance time and the secondary variables of interest were age, sex, and sino-nasal outcome test-22 scores. The control group included 40 concomitant healthy patients who visited the outpatient ear, nose and throat clinic with non-nasal symptoms.

RESULTS

The study included 40 COVID-19-positive patients and 40 healthy controls. The mean mucociliary clearance times of the study (15.53 ± 5.57 min) and control (9.50 ± 3.70 min) groups were significantly different (Z = 4.675, p < 0.001). However, the mucociliary clearance time was not significantly different between males and females (t = 0.590, p = 0.558).

CONCLUSIONS

Nasal mucociliary clearance time was prolonged in COVID-19 patients compared to healthy controls. Thus, we conclude that smell and taste are crucial symptoms that should not be overlooked in patients suspected of COVID-19 disease.

Rhinitis in patients with acquired hypothyroidism

OBJECTIVES

Our aim was to evaluate the rhinological changes during hypothyroid and euthyroid periods in patients with acquired hypothyroidism.

MATERIALS AND METHODS

The newly diagnosed 40 adult patients with hypothyroidism who presented to the Endocrinology clinic at a tertiary hospital were enrolled in the study. Patients having blood thyroid-stimulating hormone levels greater than 4.95 IU/dl were consulted to the ENT clinic. Nasal Obstruction Symptom Evaluation scores, Peak Nasal Inspiratory Flow rates and nasal mucociliary clearance time of patients were noted before and 4 months after the oral levothyroxine sodium tablet treatment.

RESULTS

Of the patients included in the study, 34 (85%) were females and 6 (15%) were males. The mean thyroid-stimulating hormone values before the treatment was 10.01 ± 3.31 IU/dl and 4.03 ± 2.45 IU/dl at the end of the treatment. The difference in values was statistically significant (p < 0.001). The mean mucociliary clearance time before treatment was 8.03 ± 3.29 min and 7.35 ± 2.87 min at the end of treatment. The decrease in mucociliary clearance time was statistically significant (p = 0.001). We did not detect any significant difference between pre- and posttreatment values of nasal obstruction symptom evaluation scores and peak nasal inspiratory flow rates.

CONCLUSION

The patients with hypothyroidism have prolonged mucociliary clearance time in hypothyroid period of the disease. Regarding to this data, we may recommend clinicians to follow-up these patients more closely for respiratory tract diseases and sinonasal infections.

Piribedil loaded thermo-responsive nasal in situ gelling system for enhanced delivery to the brain: formulation optimization, physical characterization, and in vitro and in vivo evaluation

Methyl cellulose (MC) based nasal in situ gels were developed to enhance the brain delivery of piribedil (PBD), an anti-Parkinson's drug. Different grades of MC and several solutes (NaCl, KCl, Na.Citrate, STPP, PEG-6000, sucrose, etc.) were screened to formulate thermo-responsive nasal in situ gelling systems. Formulations were evaluated for their sol-gel transition temperature and time, rheological behaviour, in vitro drug release, mucociliary clearance (MCC), ex vivo nasal toxicity, and in vivo brain availability studies in Wistar rats. Intranasal (i.n.) administration was carried out using a cannula-microtip setup to deliver PBD at the olfactory region of the nose. The concentration and viscosity grade of MC and also the concentration and type of solute used were found to affect the rheological behaviour of the formulations. Among the solutes tested, NaCl was found to be effective for formulating MC in situ gels. The developed in situ gels significantly delayed the MCC of PBD from the site of administration when compared with conventional suspension (p < 0.05). Further, formulations with higher gel strength showed lower in vitro drug release rate and longer intranasal residence (delayed MCC) (p < 0.05). The absolute brain availability (brain AUC_0-t) of PBD increased to 35.92% with i.n. delivery when compared to 4.71% with oral administration. Overall, it can be concluded that intranasal delivery of PBD is advantageous when compared to the currently practiced oral therapy. Graphical abstract.

Relationship between nasal mucociliary clearance and disease severity in children with allergic rhinitis: A comparative cross-sectional study

OBJECTIVES

Mucociliary clearance (MCC) is impaired due to chronic inflammation in allergic rhinitis. Our aim was to evaluate MCC in children with allergic rhinitis, to determine its relationship with disease severity and evaluate MCC change after nasal irrigation.

MATERIALS AND METHODS

Saccharin test was performed in 51 patients with allergic rhinitis and in 50 controls. Nasal irrigation was performed to the patients and saccharin test was repeated at the 10th minute. Total nasal symptom score (TNSS) and visual analogue scale (VAS) results were recorded. Patients were divided into mild/moderate-severe groups according to TNSS, VAS, and ARIA guidelines. Nasal MCC time (NMCCT) of the patients and the controls and NMCCT before and after nasal irrigation of the patients were compared. Correlations between NMCCT and TNSS/VAS were evaluated. NMCCTs of the mild and moderate-severe groups were compared. The cut-off values ​​were calculated to discriminate the patient group.

RESULTS

The mean NMCCT of the patient group was higher than the controls. Mean NMCCTs were different between before and after irrigation. NMCCT was higher in uncontrolled/moderate-severe groups than in controlled/mild groups. NMCCT correlated positively with VAS and TNSS. The sensitivity and specificity of NMCCT>535s were found to be 86.27% and 94%, respectively.

CONCLUSIONS

In children with allergic rhinitis, the prolongation of MCC may be identified with the easily applicable saccharin test, the deterioration in MCC increases as disease severity increases. Nasal irrigation is important in children with allergic rhinitis to improve MCC.

Impact of Nasal Irrigation With Iodized Table Salt Solution on Mucociliary Clearance: Proof-of-Concept Randomized Control Trial

Introduction

Saline nasal irrigation is a common recommendation shared between the majority of clinical guidelines for sinusitis and rhinitis in adults and children. Studies involving homemade saline have typically involved the use of noniodized salt. However, the literature does not contain any descriptions for the use of iodized table salt in homemade saline solutions.

Objectives

To study the usefulness of iodized salt in homemade saline and its impact on mucociliary clearance (MCC).

Methods

Only healthy volunteers were enrolled in this randomized controlled trial. The sinonasal outcome test (SNOT)-22 and rhinoscopy were used to rule out any clinical evidence of sinusitis or rhinitis in the enrolled subjects. The saccharine clearance time (SCT) was used to evaluate MCC at baseline. Each candidate received 2 different nasal wash solutions—one containing iodized salt and the other containing noniodized salt—on different days. Visual analog scale pain scores were recorded while using each type of nasal wash. The SCT was assessed after each wash.

Results

Thirty-eight healthy candidates (18 men and 20 women) were enrolled in the study. All subjects were in their 30s. The mean baseline SCT was 10.92 minutes. The use of the noniodized salt solution led to a nonsignificant change ( P = .139) in mean SCT (9.68 min). In contrast, a significant change ( P = .035) was observed in mean SCT after the use of the iodized salt solution (9.06 min). However, the mean postirrigation SCT was not significantly different between solutions ( P = .31). No significant differences were observed in pain/discomfort experience between solutions.

Conclusion

MCC improved with both solutions. Interestingly, the improvement was significant, when the iodized salt nasal irrigation solution was used. This finding contradicts the conventional recommendation against the use of iodized salt in nasal rinse solution. Moreover, this solution was well tolerated. Further studies regarding the long-term safety are recommended.

Mucociliary clearance in patients with continuous ambulatory peritoneal dialysis

INTRODUCTION

Mucociliary clearance (MC) is a critical defense mechanism for the protection of the entire respiratory system. Nasal colonization of some pathogens and chronical nasal infections are important risk factors for peritonitis. Any disturbance in the MC causes stasis of secretions and secondary infections.

OBJECTIVE

The aim of the study was to evaluate the patients with chronic kidney disease (CKD) receiving continuous ambulatory peritoneal dialysis (CAPD) in terms of nasal MC. More specifically, the goal is to investigate the possible correlation between the nasal MC and peritonitis.

METHODS

Forty CAPD patients and 39 healthy volunteers were involved in the study. The nasal MC was evaluated with the saccharin test, in which a 1mm diameter saccharin particle was carefully placed on the antero-medial surface of inferior nasal concha. The time taken by the subjects from the placement of particle to the perception of the sweet taste was taken as mucociliary clearance time (MCT). The groups were compared in terms of MCT. The patient group was evaluated in terms of a peritonitis history, and the correlations with MC were analyzed.

RESULTS

Patient group with CKD consisted of 16 females and 24 males with a mean age of 32.4 years; healthy individuals in the control group consisted of 17 women and 22 men with a mean age of 33.3 years. There was not a significant difference in terms of mean MC time in patients with CKD when compared with the individuals in the control group. The comparison between the mean MCT in the patients who had a history of peritonitis and patients without peritonitis was statistically significant (p<0.05).

CONCLUSIONS

Unique for being conducted with patients in continuous ambulatory peritoneal dialysis, the current study shows that although the MC of CKD patients and healthy individuals is similar, patients with low rates of MC appear to present an increased incidence of peritoneal infection. Considering the small sample investigated, an invitation to future confirmatory studies would be appropriate.

Development of a computational fluid dynamics model for mucociliary clearance in the nasal cavity

Intranasal drug delivery has attracted significant attention because of the opportunity to deliver systemic drugs directly to the blood stream. However, the mucociliary clearance poses a challenge in gaining high efficacy of intranasal drug delivery because cilia continuously carry the mucus blanket towards the laryngeal region. To better understand mucus flow behaviour on the human nasal cavity wall, we present computational model development, and evaluation of mucus motion on a realistic nasal cavity model reconstructed from CT-scans. The model development involved two approaches based on the actual nasal cavity geometry namely: (i) unwrapped-surface model in 2D domain and (ii) 3D-shell model. Conservation equations of fluid motion were applied to the domains, where a mucus production source term was used to initiate the mucus motion. The analysis included mucus flow patterns, virtual saccharin tests and quantitative velocity magnitude analysis, which demonstrated that the 3D-shell model results provided better agreement with experimental data. The unwrapped-surface model also suffered from mesh-deformations during the unwrapping stage and this led to higher mucus velocity compared to experimental data. Therefore, the 3D-shell model was recommended for future mucus flow simulations. As a first step towards mucus motion modelling this study provides important information that accurately simulates a mucus velocity field on a human nasal cavity wall, for assessment of toxicology and efficacy of intranasal drug delivery.

Olfactory bulb volume and olfactory sulcus depth in patients with Behçet's disease

OBJECTIVE

To investigate olfactory bulb volume and olfactory sulcus depth in patients with Behçet's disease, using magnetic resonance imaging.

METHODS

Cranial magnetic resonance imaging scans of 27 adults with Behçet's disease (10 males and 17 females) and 27 healthy controls were examined. Olfactory bulb volume and olfactory sulcus depth were measured on coronal, T2-weighted, spectral pre-saturation with inversion recovery sequences.

RESULTS

Bilateral olfactory bulb volume and right-sided olfactory sulcus depth were significantly lower in the Behçet's disease group than in the control group (p < 0.05). Left-sided olfactory sulcus depth increased with Behçet's disease duration. In both groups, olfactory bulb volume was significantly higher in the left than the right side. There were no gender differences for olfactory bulb volume and olfactory sulcus depth. Positive correlations were determined between right- and left-sided olfactory bulb volume values and between right- and left-sided olfactory sulcus depth values.

CONCLUSION

Behçet's disease may decrease olfactory functions, related to lower olfactory bulb volume and olfactory sulcus depth. The affected vascular system and possibly damaged neural system, nasal mucosal lesions, and prolonged nasal mucociliary clearance time may cause olfactory dysfunction. Patient follow up is recommended, with magnetic resonance imaging examinations of the olfactory system if necessary.

Tailoring Formulations for Intranasal Nose-to-Brain Delivery: A Review on Architecture, Physico-Chemical Characteristics and Mucociliary Clearance of the Nasal Olfactory Mucosa

The blood-brain barrier and the blood-cerebrospinal fluid barrier are major obstacles in central nervous system (CNS) drug delivery, since they block most molecules from entering the brain. Alternative drug delivery routes like intraparenchymal or intrathecal are invasive methods with a remaining risk of infections. In contrast, nose-to-brain delivery is a minimally invasive drug administration pathway, which bypasses the blood-brain barrier as the drug is directed from the nasal cavity to the brain. In particular, the skull base located at the roof of the nasal cavity is in close vicinity to the CNS. This area is covered with olfactory mucosa. To design and tailor suitable formulations for nose-to-brain drug delivery, the architecture, structure and physico-chemical characteristics of the mucosa are important criteria. Hence, here we review the state-of-the-art knowledge about the characteristics of the nasal and, in particular, the olfactory mucosa needed for a rational design of intranasal formulations and dosage forms. Also, the information is suitable for the development of systemic or local intranasal drug delivery as well as for intranasal vaccinations.

The Effect of the Modified Endoscopic Lothrop Procedure on the Mucociliary Clearance of the Frontal Sinus in an Animal Model

Background

The surgical management of recalcitrant frontal sinus disease has been a dilemma for otolaryngologists for many years. Although the osteoplastic flap with obliteration has been the gold standard of treatment for years, the modified endoscopic Lothrop (MEL) procedure recently has been advocated as an alternative. However, little is known about the effect of this procedure on the mucociliary drainage of the frontal sinuses postoperatively and this animal study addresses this issue.

Methods

Fourteen sheep underwent the MEL procedure. The sheep were randomized regarding the use of postoperative irrigation via minitrephines. Each sheep had a nuclear medicine γ-scintigraphy frontal sinus clearance study via minitrephines performed on each frontal sinus preoperatively and then 3 months postoperatively. Then, the results of these studies were compared.

Results

The scans revealed a trend toward faster clearance times postoperatively. However, this decrease was not statistically significant. Importantly, there was no trend or significant increase in clearance times postoperatively. Also, the use of postoperative irrigation was associated with a nonsignificant trend toward faster clearance times postoperatively.

Conclusion

The MEL procedure has no adverse effects on the mucociliary clearance of the frontal sinus at 3 months postoperatively. Irrigation of the frontal sinus in the immediate postoperative period showed a trend toward improved postoperative mucociliary function at 3 months.

Agomelatine-based in situ gels for brain targeting via the nasal route: statistical optimization, in vitro, and in vivo evaluation

Agomelatine (AGM) is an antidepressant drug with a low absolute bioavailability due to the hepatic first pass metabolism. AGM-loaded solid lipid nanoparticles were formulated in the form of an in situ gel to prolong the intranasal retention time and subsequently to increase the absorbed amount of AGM. The optimized in situ gel formula had a sol-gel transition temperature of 31 °C ± 1.40, mucociliary transport time of 27 min ±1.41%, released after 1 and 8 h of 46.3% ± 0.85 and 70.90% ± 1.48. The pharmacokinetic study of the optimized in situ gel revealed a significant increase in the peak plasma concentration, area under plasma concentration versus time curve and absolute bioavailability compared to that of the oral suspension of Valdoxan® with the values of 247 ± 64.40 ng/mL, 6677.41 ± 1996 ng.min/mL, and 37.89%, respectively. It also gave drug targeting efficiency index of 141.42 which revealed more successful brain targeting by the intranasal route compared to the intravenous route and it had direct transport percent index of 29.29 which indicated a significant contribution of the direct nose to brain pathway in the brain drug delivery.

How does radioactive iodine affect the nose?

OBJECTIVES/HYPOTHESIS

To determine the effect of radioactive iodine (RAI) treatment on the nasal mucosa and nasal functions.

STUDY DESIGN

Prospective clinical study.

METHODS

This study included 41 patients (31 female and 10 male) who were treated with RAI for papillary thyroid carcinoma. A visual analogue scale (VAS) was used for subjective evaluation of nasal symptoms. The saccharine test, nasal Schirmer test, and acoustic rhinometry were used for objective evaluation of nasal functions. All tests were administered at baseline (before RAI treatment), and then 1 month and 1 year post-RAI treatment. Only 21 of the patients could be evaluated after 1 year of treatment and were included in the study's analysis.

RESULTS

VAS obstruction and dryness scores 1 month and 1 year post-RAI were significantly higher than the baseline scores (P < .05 and P < .05, respectively). Mean cross-sectional area values 1 month and 1 year post-RAI did not differ significantly from baseline values (P > .05 and P > .05, respectively). Schirmer test results 1 month and 1 year post-RAI treatment were significantly lower than at baseline (P < .05 and P < .05, respectively). Saccharine test results 1 month and 1 year post-RAI were significantly higher than at baseline (P < .05).

CONCLUSIONS

RAI treatment can adversely affect the nasal mucosa. Nasal dryness and obstruction can occur immediately after RAI treatment. Additional research is warranted to further elucidate the effects of RAI treatment on nasal function.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2698-2702, 2017.

Late-term Effects of Surgery on Nasal Functions in Patients who Underwent Total Laryngectomy Surgery

Introduction  There is a common opinion that losing airway functions in total laryngectomy patients cause changes in nasal physiological rates. Studies conducted to review the subject present gaps, especially in terms of objective measurements.

Objective  We evaluated late-term effects of surgery on nasal functions in patients who underwent total laryngectomy surgery more than two years ago.

Methods  We included in the study 22 patients who had undergone total laryngectomy, as well as 24 healthy subjects with similar demographic characteristics as the control group. We performed acoustic rhinometry for intranasal volume and cross-sectional area measurements, saccharin test for measurement of nasal mucociliary clearance, and smell identification test for evaluation of olfactory function in the patient and control groups. We compared and statistically analyzed the data obtained from the groups.

Results  In our study, although late-term (>2 years) measurements were not statistically significant, we detected more nasal passage patency in the patient group than in the control group. In smell identification test, lower scores were obtained in the patient group. The difference between measurements in both groups was statistically significant.

Conclusion  We believe that since the upper respiratory tract is disabled due to tracheostomy in patients with total laryngectomy, atrophy occurs in the late term and, consequently, nasal mucociliary clearance is impaired. We also see diminished olfactory function in total laryngectomy patients.

Tolerability of Nasal Delivery of Humidified and Warmed Air at Different Temperatures: A Randomised Double-Blind Pilot Study

Objectives. Delivery of warmed, humidified air via nasal high flow therapy could potentially reduce replication of temperature-sensitive viruses in the upper respiratory tract. This study investigates whether nasal high flow therapy is well tolerated by healthy adults at 37°C and 41°C. Methods. In this randomised, double-blind, controlled crossover pilot trial, nasal high flow therapy was used to deliver humidified air at 35 L/min, at either 37°C or 41°C, for three one-hour sessions of use over one day. The alternative was delivered at least 14 days later. Ten healthy, nonsmoking adults were asked, via questionnaire after each day's use, whether they would use nasal high flow therapy while being unwell with a cold or flu if it was demonstrated to improve symptoms. Results. All participants completed both interventions. Eighty percent responded “yes” to future use of nasal high flow therapy, for both 37°C and 41°C. There was no significant change from baseline in saccharin times following either intervention or in the following morning. Conclusions. Delivering humidified air via nasal high flow therapy at both 37°C and 41°C is well tolerated by healthy adults. This supports investigation into the potential use of nasal high flow therapy as treatment in viral upper respiratory tract infections. Trial Registration. This trial is registered with ACTRN12614000183684 (tolerability study of nasal delivery of humidified & warmed air).

Assessment of nasal mucociliary activity in patients with Behçet's disease

OBJECTIVE

To investigate nasal mucociliary clearance in patients with Behçet's disease.

METHODS

Thirty patients with Behçet's disease, diagnosed on the basis of criteria defined by the International Study Group for Behçet's Disease, and 30 healthy individuals were recruited. In both groups, individuals with conditions that could affect nasal mucociliary clearance were excluded. Nasal mucociliary clearance time was evaluated using saccharin tests. The time between placement of a saccharin tablet and the tasting of the saccharin was measured and recorded as the saccharin clearance time.

RESULTS

The mean nasal mucociliary clearance time was significantly longer in the Behçet's disease patients than in the control subjects (p < 0.001). Furthermore, there was a positive correlation between Behçet's disease duration and nasal mucociliary clearance time (p < 0.001, r = 0.882).

CONCLUSION

The results suggest that nasal mucociliary clearance time is longer in Behçet's disease patients than in control subjects, and is positively correlated with disease duration.

Micro-anatomical and functional assessment of ciliated epithelium in mouse trachea using optical coherence phase microscopy

Motile cilia perform a range of important mechanosensory and chemosensory functions, along with expulsion of mucus and inhaled pathogens from the lungs. Here we demonstrate that spectral domain optical coherence phase microscopy (SD-OCPM), which combines the principles of optical coherence tomography (OCT) and confocal microscopy, is particularly well-suited for characterization of both morphology and the ciliary dynamics of mouse trachea. We present micro-anatomical images of mouse trachea, where different cell types can be clearly visualized. The phase contrast, which measures the sub-nanometer changes in axial optical pathlength is used to determine the frequency and direction of cilia beatings.

Effects of rapid maxillary expansion on nasal mucociliary clearance

OBJECTIVE

To evaluate the changes in nasal mucociliary clearance in orthodontic patients after rapid maxillary expansion (RME) therapy.

MATERIALS AND METHODS

Forty-two children (25 boys and 17 girls) participated in this study. The RME group consisted of 21 patients (mean age, 13.8 years), who had undergone RME at the initiation of orthodontic treatment. The control group consisted of 21 subjects (mean age, 13.6 years), who were attending the department of orthodontics for active orthodontic treatment. The nasal mucociliary clearance was assessed by the saccharin test. Saccharin transit times (STTs) were measured for each treated subject before expansion (T1), after RME (T2), and after a 3-month retention period (T3). Records were obtained at the same time intervals for each group.

RESULTS

The STT decreased significantly in the RME group after expansion and retention (P < .05). A statistically significant difference was found when the STTs of the control and RME groups were compared after expansion and retention (P < .05).

CONCLUSIONS

The STTs of young orthodontic patients with maxillary narrowness and without any history of nasal or systemic disease were within normal limits. However, RME increased the mucociliary clearance in patients who had maxillary narrowness, having positive effects on nasal physiology and increasing nasal cavity volume.

The effect of cilia and the mucociliary clearance on successful drug delivery

Nasal mucociliary clearance is one of the most important factors affecting nasal delivery of drugs and vaccines. This is also the most important physiological defense mechanism inside the nasal cavity. It removes inhaled (and delivered) particles, microbes and substances trapped in the mucus. Almost all inhaled particles are trapped in the mucus carpet and transported with a rate of 8-10 mm/h toward the pharynx. This transport is conducted by the ciliated cells, which contain about 100-250 motile cellular appendages called cilia, 0.3 µm wide and 5 µm in length that beat about 1000 times every minute or 12-15 Hz. For efficient mucociliary clearance, the interaction between the cilia and the nasal mucus needs to be well structured, where the mucus layer is a tri-layer: an upper gel layer that floats on the lower, more aqueous solution, called the periciliary liquid layer and a third layer of surfactants between these two main layers. Pharmacokinetic calculations of the mucociliary clearance show that this mechanism may account for a substantial difference in bioavailability following nasal delivery. If the formulation irritates the nasal mucosa, this mechanism will cause the irritant to be rapidly diluted, followed by increased clearance, and swallowed. The result is a much shorter duration inside the nasal cavity and therefore less nasal bioavailability.

Mucociliary transport and histopathological changes in rotation flaps of the nasal mucosa

Normal mucociliary transport in the mucoperichondrium of the nasal septum is from a distal (anterior) to proximal (posterior) direction. This study was to determine the direction of mucociliary transport and histopathological changes in nasal mucosal rotation flaps when their transport directions were anatomically reversed. Thirty-two rabbits were divided into four groups. Surgical septal rotational flaps were prepared in the experimental groups. Group I was the control group. The distal aspect of the flap was sutured through a large septal window to the other side of the nasal septum, thus changing the direction of the flap. Evaluation was performed 1 week, 1 month and 9 months later with each of these groups named as groups II, III, and IV, respectively. The rate and direction of the mucociliary transport was determined and histopathological investigations were performed from the flaps. The direction of mucociliary transport was observed to continue as distal to proximal direction in the rotated segments. The mucociliary transport rate was found to be decreased in group II, nearly normal in group III, and in normal limits in group IV after surgery. Intense inflammation and decreased number of cilia were present in group II. The inflammation was milder in group III and the epithelium was found to be nearly normal in group IV. The originally programmed direction of mucociliary transport in the nasal rotation flaps is maintained and is not altered or reprogrammed. Histopathological changes revert back to normal from an inflammatory state to reach pre-surgical status over time.

Nasal in-situ gels for delivery of rasagiline mesylate: improvement in bioavailability and brain localization

Intranasal thermosensitive gel for rasagiline mesylate (RM) was developed for effective treatment of Parkinson's disease. Intranasal gels were prepared by combination of poloxamer 407 and poloxamer 188 (1:1) with mucoadhesive polymers (carbopol 934 P and chitosan). The formulations were evaluated for sol-gel transition temperature, in-vitro drug release and in-vivo mucociliary transit time. Further, optimal intranasal gel formulations were tested for in-vivo pharmacokinetic behavior, nasal toxicity studies and brain uptake studies. It was found that optimal formulations had acceptable gelation temperature (28-33 °C) and adequate in-vitro drug release profile. Pharmacokinetic study in rabbits showed significant (p < 0.05) improvement in bioavailability (four- to six-folds) of the drug from intranasal gels than oral solution. Chronic exposure studies in Wistar rats showed that these intranasal gels were non-irritant and non-toxic to rat nasal mucosa. Estimation of RM in rat brain tissue showed significant (p < 0.01) improvement in uptake of RM form intranasal gel formulations than nasal solution.

Evaluation of nasal mucociliary activity in iatrogenic hypothyroidism

Our aim was to evaluate the effects of iatrogenic, acute and deep hypothyroidism on nasal mucociliary clearance. A total of 46 patients undergoing total or near total thyroidectomy for differentiated thyroid cancer between March and June 2012, and scheduled to undergo radioactive iodine (I-131) ablation therapy followed with an induced hypothyroidism for routine screening were included in the study. Mucociliary clearance test was made during hypothyroid and euthyroid periods in all the patients included in the study. Of the 46 patients included in the study, 37 (%80.4) were females, 9 (%19.6) were males, and the average mucociliary clearance times were 16.78 and 9.58 min during hypothyroid and euthyroid periods, respectively. When the results were compared statistically, mucociliary clearance time measured during hypothyroidism period was found to be significantly longer than the one measured during euthyroid period. Mucociliary clearance time was found to be long during iatrogenic acute and deep hypothyroid periods. During these periods, patients should be followed closely for lower and upper respiratory tract infections.

Enhanced brain targeting of curcumin by intranasal administration of a thermosensitive poloxamer hydrogel

OBJECTIVES

The aim of this study was to develop a curcumin intranasal thermosensitive hydrogel and to improve its brain targeting efficiency.

METHODS

The hydrogel gelation temperature, gelation time, drug release and mucociliary toxicity characteristics as well as the nose-to-brain transport in the rat model were evaluated.

KEY FINDINGS

The developed nasal hydrogel, composed of Pluronic F127 and Poloxamer 188, had shorter gelation time, longer mucociliary transport time and produced prolonged curcumin retention in the rat nasal cavity at body temperature. The hydrogel release mechanism was diffusion-controlled drug release, evaluated by the dialysis membrane method, but dissolution-controlled release when evaluated by the membraneless method. A mucociliary toxicity study revealed that the hydrogel maintained nasal mucosal integrity until 14 days after application. The drug-targeting efficiencies for the drug in the cerebrum, cerebellum, hippocampus and olfactory bulb after intranasal administration of the curcumin hydrogel were 1.82, 2.05, 2.07 and 1.51 times that after intravenous administration of the curcumin solution injection, respectively, indicating that the hydrogel significantly increased the distribution of curcumin into the rat brain tissue, especially into the cerebellum and hippocampus.

CONCLUSIONS

A thermosensitive curcumin nasal gel was developed with favourable gelation, release properties, biological safety and enhanced brain-uptake efficiency.

Does passive smoking have an effect on nasal mucociliary clearance?

OBJECTIVE

The aim of this study is to review the literature about nasal mucociliary clearance (MCC) and passive smoking in otorhinolaryngology by clearly explaining their relationship in a cross-sectional study.

STUDY DESIGN AND SETTING

This cross-sectional study was conducted at the Umraniye Education and Research Hospital in Turkey. Umraniye Education and Research Hospital Ethical Committee approved the study, and informed consents of the patients were obtained.

METHODS

Our study consisted of patients who presented to the Ear-Nose-Throat Department of Istanbul Umraniye Education and Research Hospital between February 2011 and July 2011. Three groups of subjects were evaluated: 15 passive smokers (group 1), 17 active smokers (group 2), and 15 healthy matched controls (group 3). All patients were asked to answer our questions regarding their smoking history, and nasal MCC time was assessed for all individuals of the 3 groups.

RESULTS

The mean MCC value was 23.59 ± 12.41 in the smoking group, 12.6 ± 4.67 in the passive smoking group, and 6.4 ± 1.55 in the healthy group. The comparison of MCC values between the smoking group and passive smoking group and between the smoking group and healthy group revealed statistically significant differences (P < .01). There was also a significant difference between the MCC values of the passive smoking group and the healthy group (P < .01). In addition, we compared MCC values according to exposure number of cigarettes.

CONCLUSION

In this study, we conclude that passive smoking affects nasal MCC. Both active and passive smoking increases nasal MCC time when compared with healthy controls.

Endoscopic dacryocystorhinostomy appears to impair nasal mucociliary clearance

We conducted a prospective study of 50 adults to investigate changes in nasal mucociliary clearance following endoscopic intranasal dacryocystorhinostomy (DCR). Each operation was performed with the use of a drill to perforate the lateral nasal wall in order to reach the lacrimal sac. Each patient's mucociliary clearance time (MCT) was determined by the saccharin test on both the operated and nonoperated sides; the preoperative times were compared with postoperative measurements made 1 and 3 months following DCR. Preoperatively, the mean MCTs were 14.48 minutes on the operated side and 14.50 minutes on the nonoperated side-not a statistically significant difference (p > 0.05). Postoperatively, the corresponding MCTs were 25.22 and 14.98 minutes at 1 month and 18.44 and 15.62 minutes at 3 months. On the operated side, both postoperative MCTs were significantly longer than the preoperative value (p < 0.001), while on the nonoperated side, neither postoperative MCT was significantly different from the preoperative value (p > 0.05). Also, the postoperative MCTs were significantly longer on the operated side than on the nonoperated side at both 1 month (p < 0.001) and 3 months (p < 0.05). Only 1 of the 50 operations was considered to be unsuccessful; the reason for this surgical failure was the patient's ongoing complaints of chronic postoperative dacryocystitis. We conclude that endoscopic DCR disturbs mucociliary clearance. Changes in MCTs may be attributable to injury to the nasal mucosa or to the continuous flow of tears through the nasal mucosa.

Quantitative single-exposure x-ray phase contrast imaging using a single attenuation grid

A single-exposure quantitative method of x-ray phase contrast imaging, suitable for animal in vivo observations, is described and shown experimentally both for a known static sample and an ex vivo biological airway. The ability to acquire the desired information within a single exposure is important for dynamic samples, as is sufficient sensitivity to reveal small variations in the composition or thickness of such a sample. This approach satisfies both these needs by analyzing how a reference grid pattern is deformed by the presence of the sample, similar to a Shack-Hartmann sensor. By resolving the shift of the pattern into horizontal and vertical components, a quantitative phase depth map is recovered, sensitive to both sharp edges as well as low phase gradients.

Measuring critical care air support teams' performance during extended periods of duty

The Royal Air Force (RAF) Critical Care Air Support Teams (CCASTs) aeromedically evacuate seriously injured service personnel. Long casualty evacuation chains create logistical constraints that must be considered when aeromedically evacuating patients. One constraint is the length of a CCAST mission and its potential effect on team member performance. Despite no evidence of patient care compromise, the RAF has commissioned a study to investigate whether CCAST mission length influences performance. Describing and understanding the role of a CCAST enabled fatigue to be defined. Factors essential to studying fatigue were then identified that were used to develop a theoretical model for designing a study to measure the effects of fatigue on CCAST performance. Relevant factors include the patient's clinical condition, team members' cognition and vigilance levels, and the occupational aviation environment. Further factors influencing overall performance include the duration and complexity of patient interventions, mission length, circadian influences, and fatigue countermeasures.

Chemosensory loss: functional consequences of the world trade center disaster

BACKGROUND

Individuals involved in rescue, recovery, demolition, and cleanup at the World Trade Center (WTC) site were exposed to a complex mixture of airborne smoke, dust, combustion gases, acid mists, and metal fumes. Such exposures have the potential to impair nasal chemosensory (olfactory and trigeminal) function.

OBJECTIVE

The goal of this study was to evaluate the prevalence of chemosensory dysfunction and nasal inflammation among these individuals.

METHODS

We studied 102 individuals who worked or volunteered at the WTC site in the days and weeks during and after 11 September 2001 (9/11) and a comparison group with no WTC exposure matched to each participant on age, sex, and job title. Participants were comprehensively evaluated for chemosensory function and nasal inflammation in a single session. Individual exposure history was obtained from self-reported questionnaires.

RESULTS

The prevalence of olfactory and trigeminal nerve sensitivity loss was significantly greater in the WTC-exposed group relative to the comparison group [prevalence ratios (95% confidence intervals) = 1.96 (1.2-3.3) and 3.28 (2.7-3.9) for odor and irritation thresholds, respectively]. Among the WTC responders, however, individuals caught in the dust cloud from the collapse on 9/11 exhibited the most profound trigeminal loss. Analysis of the nasal lavage samples supported the clinical findings of chronic nasal inflammation among the WTC-exposed cohort.

CONCLUSIONS

The prevalence of significant chemosensory impairment in the WTC-exposed group more than 2 years after their exposure raises concerns for these individuals when the ability to detect airborne odors or irritants is a critical safety factor.

RELEVANCE TO CLINICAL PRACTICE

This outcome highlights the need for chemosensory evaluations among individuals with exposure to acute high or chronic levels of airborne pollutants.

Deleterious effect of smoking and nasal septal deviation on mucociliary clearance and improvement after septoplasty

OBJECTIVES

To investigate the effect of septal deviation, septoplasty, and smoking upon nasal mucociliary clearance by using saccharine test.

METHODS

Included in this study were 40 patients (15 women and 25 men) who had septal deviation and septoplasty surgery performed between March and June 2006. Patients are classified into three groups: group I (n = 20) nonsmoking patients who had septoplasty surgery, group II (n = 20) smoking patients who had septoplasty surgery, and the control (n = 20) group. None of the control group has nasal breathing problem or smoking history. For determining preoperative and postoperative nasal mucociliary clearance (MCC) time, a saccharine test was performed on the patients 1 day before surgery and at the third month of postoperative control.

RESULTS

Preoperative and postoperative nasal MCC time in patients of group I are statistically significantly lower than the group II (p < 0.01). Postoperative MCC time in group I and II is significantly decreased compared with preoperative MCC time, statistically (p < 0.01). Preoperative and postoperative MCC time of group I and group II is significantly higher than MCC time of the control group (p < 0.01).

CONCLUSION

Nasal septal deviation and smoking deteriorates nasal MCC time and this result can be shown easily with the saccharine test. Properly performed septoplasty surgery decreases nasal MCC time during the late postoperative period but MCC times are still longer than normal. The saccharine test can be used for following up the effect of septoplasty upon nasal mucosa.

Objective monitoring of nasal patency and nasal physiology in rhinitis

Nasal obstruction can be monitored objectively by measurement of nasal airflow, as evaluated by nasal peak flow, or as airways resistance/conductance as evaluated by rhinomanometry. Peak flow can be measured during inspiration or expiration. Of these measurements, nasal inspiratory peak flow is the best validated technique for home monitoring in clinical trials. The equipment is portable, relatively inexpensive, and simple to use. One disadvantage, however, is that nasal inspiratory peak flow is influenced by lower airway as well as upper airway function. Rhinomanometry is a more sensitive technique that is specific for nasal measurements. The equipment, however, requires an operator, is more expensive, and is not portable. Thus, it is applicable only for clinic visit measures in clinical trials. Measurements require patient cooperation and coordination, and not all can achieve repeatable results. Thus, this objective measure is best suited to laboratory challenge studies involving smaller numbers of selected volunteers. A nonphysiological measure of nasal patency is acoustic rhinometry. This sonic echo technique measures internal nasal luminal volume and the minimum cross-sectional area. The derivation of these measures from the reflected sound waves requires complex mathematical transformation and makes several theoretical assumptions. Despite this, however, such measures correlate well with the nasal physiological measures, and the nasal volume measures have been shown to relate well to results obtained by imaging techniques such as computed tomography scanning or magnetic resonance imaging. Like rhinomanometry, acoustic rhinometry is not suitable for home monitoring and can be applied only to clinic visit measures or for laboratory nasal challenge monitoring. It has advantages in being easy to use, in requiring little patient cooperation, and in providing repeatable results. In addition to nasal obstruction, allergic rhinitis is recognized to be associated with impaired mucociliary clearance and altered nasal responsiveness. Measures exist for the monitoring of these aspects of nasal dysfunction. Although measures of mucociliary clearance are simple to perform, they have a poor record of reproducibility. Their incorporation into clinical trials is thus questionable, although positive outcomes from therapeutic intervention have been reported. Measures of nasal responsiveness are at present largely confined to research studies investigating disease mechanisms in allergic and nonallergic rhinitis. The techniques are insufficiently standardized to be applied to multicenter clinical trials but could be used in limited-center studies to gain insight into the regulatory effects of different therapeutic modalities.

Scaling of the first ethmoturbinal in nocturnal strepsirrhines: olfactory and respiratory surfaces

Turbinals (scroll bones, turbinates) are projections from the lateral wall of the nasal fossa. These bones vary from simple folds to branching scrolls. Conventionally, maxilloturbinals comprise the respiratory turbinals, whereas nasoturbinals and ethmoturbinals comprise olfactory turbinals, denoting the primary type of mucosa that lines these conchae. However, the first ethmoturbinal (ETI) appears exceptional in the variability of it mucosal covering. Recently, it was suggested that the distribution of respiratory versus olfactory mucosae varies based on body size or age in strepsirrhine primates (lemurs and lorises). The present study was undertaken to determine how the rostrocaudal distribution of olfactory epithelium (OE) versus non-OE scales relative to palatal length in strepsirrhines. Serially sectioned heads of 20 strepsirrhines (10 neonates, 10 adults) were examined for presence of OE on ETI, rostral to its attachment to the nasal fossa wall (lateral root). Based on known distances between sections of ETI, the rostrocaudal length of OE was measured and compared to the length lined solely by non-OE (primarily respiratory epithelium). In 13 specimens, the total surface area of OE versus non-OE was calculated. Results show that the length of non-OE scales nearly isometrically with cranial length, while OE is more negatively allometric. In surface area, a lesser percentage of non-OE exists in smaller species than larger species and between neonates and adults. Such results are consistent with recent suggestions that the olfactory structures do not scale closely with body size, whereas respiratory structures (e.g., maxilloturbinals) may scale close to isometry. In primates and perhaps other mammals, variation in ETI morphology may reflect dual adaptations for olfaction and endothermy.

Benzalkonium chloride and nasal mucociliary clearance: a randomized, placebo-controlled, crossover, double-blind trial

BACKGROUND

Benzalkonium chloride (BKC) has been considered an innocuous preservative for prescription drugs.

METHODS

We performed a double-blind, placebo-controlled, randomized, crossover, single-center trial with a 3-week washout period in 43 healthy volunteers comparing the effect of 3-week use of saline nasal spray containing BKC 0.01% to preservative-free saline t.i.d. on nasal mucociliary clearance rate. Evaluations were done at the beginning and the end of each period by gamma-scintigraphy with technetium99m-labeled strontium.

RESULTS

Nasal mucociliary clearance rate was significantly impaired by BKC with a difference of 1.23 mm x min(-1) (p < 0.01) between periods.

CONCLUSION

BKC in the concentration used in nasal preparations impaired mucociliary clearance in healthy individuals after 3 weeks of use. Presently, when preservative-free alternatives are available, BKC could be a risk without benefit.

Effect of 1-deamino 8-D-arginine vasopressin spray on nasal cytology and mucociliary clearance in patients with nocturnal enuresis

OBJECTIVE

To determine any possible adverse effect of 1-deamino 8-D-arginine vasopressin (DDAVP) spray on nasal cytology and mucociliary clearance in patients with nocturnal enuresis.

METHODS

Twenty-two children aged 6-16 enrolled in the study. Epithelial surface cells samples were taken from the nasal mucosa and mucociliary clearance time was calculated before and 1 and 6 months after administration of DDAVP spray.

RESULTS

No qualitative changes in the epithelial surface cells and mucociliary clearance time were observed at 1 and 6 months after therapy.

CONCLUSION

Based on the findings of the present study, DDAVP spray can be used for 6 months in children without apparent risk of damage to the epithelial surface cells and mucociliary clearance time.

High-speed digital imaging method for ciliary beat frequency measurement

The aim of this study was to develop a high-speed digital imaging system and related software for ciliary beat frequency (CFB) analysis in order to establish an automated and reliable method that is observer independent and faster compared to the conventional computerized microscope photometry method. Using primary human nasal epithelial cell cultures, the CBF was recorded with a computerized microscope photometry system and a high-speed digital imaging system. To obtain a wide range of frequencies, glycocholate (0.5%) and chlorocresol (0.005%) were used as ciliostimulatory and cilio-inhibitory reference compounds, respectively. The mean values in hertz (+/- s.d.) obtained with the photometry and high-speed digital imaging systems were: controls 8.2 +/- 0.9 and 7.9 +/- 1.1; chlorocresol 5.0 +/- 0.9 and 5.1 +/- 1.1; glycocholate 9.8 +/- 1.0 and 9.7 +/- 0.8. A similar increase (by 20 and 24%) and decrease (by 38 and 35%) in CBF was determined by the two methods after glycocholate and chlorocresol treatment, respectively. The mean difference between the photometry and high-speed digital imaging methods was 0.2 +/- 0.6 Hz, and the Bland-Altman limits of agreement were from -1.0 to +1.4 Hz, suggesting that the results obtained by these two methods could be used interchangeably. These results show the reliability of the high-speed digital imaging system and the software developed for in-vitro CBF measurements. The advantages of the system include: (i) fast data acquisition and calculation, (ii) whole field automated CBF analysis and (iii) reduction in selection bias.