Nasal Nitric Oxide Concentration Research Articles

Whole-exome sequencing identified novel DNAH5 homozygous variants in two consanguineous families with primary ciliary dyskinesia.

Whole-exome sequencing identified novel DNAH5 homozygous variants in two consanguineous families with primary ciliary dyskinesia.

Numerical study on the distribution of nitric oxide concentration in the nasal cavity of healthy people during breathing

BackgroundIn the nasal cavity, nitric oxide (NO) is involved in many physiological functions, including antibacterial and antiviral activity, promotion of nasal mucociliary clearance, and regulation of blood vessel expansion in the nasal mucosa. We investigated the distribution of NO concentration in the nasal cavity of healthy individuals during breathing. MethodsA three-dimensional numerical model of the nasal airway, including the bilateral maxillary sinuses, was created to simulate NO distribution in the nasal cavity during normal breathing. The effect of different nasal airflow velocities and NO concentrations in the maxillary sinus on NO distribution in the nasal cavity was evaluated. The NO concentration in the nasal exhalation of 50 healthy people in Dalian was measured using an NO analyzer, and the growth rate of the NO concentration in the nasal cavity was measured under breath-holding conditions. ResultsThe distribution of NO concentration in the nasal cavity of healthy people during breathing was obtained from numerical simulation results. Lower the airflow rate, higher was the NO concentration and greater was the diffusion range in the nasal cavity. The NO concentration in the nasal cavity increased with an increase in its concentration in the maxillary sinus, indicating a linear relationship. The NO concentration in the nasal exhalation of healthy people in Dalian and the growth rate of the NO concentration in the nasal cavity under breath-holding conditions were obtained through experiments. The numerical results correspond with the experimental results. ConclusionsThe NO entered the nasal cavity mainly by diffusion and followed the convection flow of the respiratory air in the nasal cavity. NO concentration in the nasal cavity was related to the respiratory airflow velocity and NO concentration in the maxillary sinus. During inspiration, NO was present only in the nasal airway posterior to the maxillary sinus ostium, whereas during exhalation, the exhaled NO diffusely distributed throughout the nasal cavity.

Nasal and tracheobronchial nitric oxide production and its influence on oxygenation in horses undergoing total intravenous anaesthesia

BackgroundThe present study aimed to investigate the effect of endotracheal intubation on nasal and tracheal endogenous NO concentrations, gas exchange and oxygenation in horses undergoing general anaesthesia. In many species a major part of physiological nitric oxide (NO) production takes place in the nasopharynx. Inhaled NO acts as a pulmonary vasodilator and regulates lung perfusion and endotracheal intubation bypasses the nasopharynx. Six horses were randomly assigned to either the “intubated” (INT) or the “non-intubated” (nINT) treatment group. Horses were premedicated with dexmedetomidine (5 μg/kg IV). Anaesthesia was induced with 2.5 mg/kg ketamine and 0.05 mg/kg diazepam IV, and it was maintained by administration of a triple-drip (100 mg/kg/h guaifenesin, 4 mg/kg/h ketamine, 7 μg/kg/h dexmedetomidine). The horses were spontaneously breathing room air. Heart rate, cardiac output, arterial blood pressure, pulmonary arterial blood pressures and respiratory rate were recorded during a 100-min anaesthesia period. Arterial, venous and mixed venous blood samples were taken every 10 minutes and analysed for partial pressure of oxygen (PO2) and carbon dioxide (PCO2), oxygen saturation and haemoglobin content. Standard oxygenation indices were calculated. Nasal and tracheal endogenous NO concentration was determined by chemiluminescence.ResultsCardiovascular variables, respiratory rate, PO2, PCO2, oxygen saturation, haemoglobin content, CaO2, O2ER, P(a-ET)CO2 and Qs/Qt did not differ significantly between the two treatment groups. The P(A-a)O2 was significantly higher in INT (6.1 ± 0.3 kPa) compared to nINT (4.9 ± 0.1 kPa) (p = 0.045), respectively. The nasal (8.0 ± 6.2 ppb) and tracheal (13.0 ± 6.3 ppb) endogenous NO concentration differed significantly in INT (p = 0.036), but not in nINT (nasal: 16.9 ± 9.0 ppb; tracheal: 18.5 ± 9.5 ppb) (p = 0.215).ConclusionEndotracheal intubation reduces the nasal and tracheal endogenous NO concentration. The influence on pulmonary gas exchange and oxygenation is negligible in horses breathing room air.

A Single-Center, Randomized, 3-Way, Crossover Study to Evaluate the Effect of an Exhalation Delivery System on Nasal Nitric Oxide Concentrations in Patients with Chronic Rhinosinusitis Compared with Healthy Participants

Nasal nitric oxide (nNO) is produced within the sinuses and has anti-inflammatory activity. In patients with chronic rhinosinusitis (CRS), nNO is depressed, likely because inflammation restricts nNO release from the sinuses. The positive pressure produced by the Exhalation Delivery System (EDS) in the nasal cavity has the potential to open up the sinus ostia, allowing release of nNO. Increasing nNO may improve patient symptoms.

Study on nasal nitric oxide concentrations of 50 healthy individuals in Dalian

Objective:To measure the normal value of nasal nitric oxide（nNO） concentration of 50 healthy adults in Dalian. By investigating the changing trend of nitric oxide accumulation concentration in the nasal cavity when changing the duration of nasal non-ventilation under quiet state, to provide ideas for the noninvasive detection of the concentration of nitric oxide in the sinus and the patency of the sinus ostium. Methods:①The left and right nNO concentrations（LnNO, RnNO） of 50 healthy subjects in Dalian were measured by Sunvou-CA2122（Wuxi）, and the LnNO₁₀, LnNO₂₀, and LnNO₃₀ were measured through the left nasal cavity when the the time of nasal non ventilation was set for 10 s, 20 s, 30 s respectively. Ten subjects with good cooperation extended the time of nasal non ventilation to 50 s, and the measured nNO value was denoted as LnNO₅₀. ②Statistical analysis was performed by SPSS 19.0, and differences between two sides of nNO were analyzed by t-test, and the trend of changes in concentration of NO accumulation in the nasal cavity when changing the duration of nasal nonventilation was investigated by One-way repeated measures ANOVA. Results:①The mean LnNO concentration in 50 healthy subjects was （383.32±126.35） ×10⁻⁹, the mean RnNO concentration was （395.26±124.32） ×10⁻⁹, and there was no significant difference between the two side（P>0.05）, and the mean nNO was （389.29±124.85） ×10⁻⁹. ②The mean nNO concentration measured at 10, 20, and 30 seconds nasal nonventilation were （984.54±477.69） ×10⁻⁹ for LnNO₁₀, （1527.32±717.25） ×10⁻⁹ for LnNO₂₀, （2183.26±946.21） ×10⁻⁹ for LnNO₃₀, and（3083.00±1905.62） ×10⁻⁹ for LnNO₅₀ measured at prolonging nasal nonventilation time to 50 seconds for ten of these subjects; The difference in the presence of increased nNO concentrations measured after prolonged nasal nonventilation was statistically significant（P<0.01）. Conclusion:①The values of nNO of 50 healthy individuals in Dalian were（389.29±124.85） ×10⁻⁹. ②In healthy individuals, nNO can be measured unilaterally instead of bilaterally. ③In quiet condition, the duration of nasal nonventilation was prolonged for a certain period of time, and the nNO concentration showed a gradually increasing trend. It is expected to provide ideas for noninvasive detection of NO concentration in nasal sinuses and patency of nasal sinuses.

Measurements of upper and lower airway nitric oxide in healthy adults

Introduction. Nasal nitric oxide (NO) measurement can be a useful tool for monitoring upper airway diseases. However, there is a considerable lack of validation data. Aims. To evaluate the repeatability and intra-subject variations of nasal NO output (nV NO) in healthy adults and to study its correlation with lower airway NO parameters. Methods. nV NO was measured in healthy non-smokers at baseline (N = 31, age: 28 ± 6 years), after 1 h (N = 15), 1 d (N = 15), 1 week (N = 17), and compared using the Bland–Altman method. At baseline, lower airway NO parameters (F ENO, flux of NO in the conducting airways and alveolar NO concentration) were also measured and correlated to nV NO (Spearman correlation). Multivariate regression analysis was used to assess the factors influencing nV NO. Results. Baseline median nV NO was 465 (interquartile range (IQR) = 404–536) nL min−1. The mean differences between the baseline and repeated measurements were not significant (p > 0.05). The coefficient of repeatability (mean: 118, IQR = 88–181 nL min−1) and coefficient of variation (mean: 9.1%) were low. We found no correlation between nV NO and lower airway NO parameters (p > 0.05). Sex (β = −0.52, p = 0.02) and body weight (β = −0.65, p = 0.03) influenced nV NO (model: p = 0.04, R 2 = 0.31). Conclusion. nasal NO output has good repeatability in healthy adults. The NO productions of lower and upper airways are not related in health, but nasal NO output seems to be affected by sex and body weight.

Computational modeling of nasal nitric oxide flux from the paranasal sinuses: Validation against human experiment.

Nitric oxide (NO) is important in respiratory physiology and airway defense. Although the paranasal sinuses are the major source of nasal NO, transport dynamics between the sinuses and nasal cavities are poorly understood. Exhaled nasal NO tracings were measured in two non-asthmatic subjects (one with allergic rhinitis, one without) using NO analyzer connected via face mask. We subsequently performed computational fluid dynamics NO emission simulations based on individual CT scans and compared to the experimental data. Simulated exhaled NO tracings match well with experimental data (r>0.84, p<0.01) for both subjects, with measured peaks reaching 319.6ppb in one subject (allergic-rhinitis), and 196.9ppb in the other. The CFD simulation accurately captured the peak differences, even though the initial sinus NO concentration for both cases was set to the same 9000ppb based on literature value. Further, the CFD simulation suggests that ethmoid sinuses contributed the most (>67%, other sinuses combined <33%) to total nasal NO emission in both cases and that diffusion contributes more than convective transport. By turning off diffusion (setting NO diffusivity to ~0), the NO emission peaks for both cases were reduced by >70%. Historically, nasal NO emissions were thought to be contributed mostly by the maxillary sinuses (the largest sinuses) and active air movement (convection). Here, we showed that the ethmoid sinuses and diffusive transport dominate the process. These findings may have a substantial impact on our view of nasal NO emission mechanisms and sinus physiopathology in general.

Analysis of the clinical features of Japanese patients with primary ciliary dyskinesia

ObjectivePrimary ciliary dyskinesia (PCD) is a rare hereditary disease. Most reports of PCD in Japan are case reports, and clinical analysis has not been performed. Differences in the causative genes might affect the clinical features in different ethnic groups. The purpose of this study was to clarify the clinical features of Japanese patients with PCD. MethodsWe performed a retrospective chart review of PCD patients seen at Mie University Hospital and patients whose blood samples were sent to us for genetic analysis from 2011 to 2020. Data on the following items were collected and analyzed: age at first visit to the hospital, age at diagnosis of PCD, process of referral to our facility, chief complaint, situs status, PrImary CiliARy DyskinesiA Rule (PICADAR) score, nasal nitric oxide concentration, otoscopic findings, rhinoscopic findings, and paranasal computed tomography scan findings. ResultsSixty-seven patients (24 male, 43 female) were diagnosed with PCD during the study period. Age at diagnosis ranged from 2 months to 69 years (median, 17 years). Respiratory symptoms (77%) were the most common complaint, followed by nasal (15%) and aural (8%) symptoms. Situs inversus was present in 17 (25%) cases. Only 2 cases had congenital cardiac anomalies. The mean PICADAR score was 7.3 (range, 3–14) points. Approximately 50% of tympanic membranes showed retraction, suggesting otitis media with effusion. The mean Lund-Mackay score was 12.8 (range, 7–17) points, suggesting that the radiographic findings were not always severe. There was no significant difference in the total Lund-Mackay score between patients with and without situs inversus (12.7 vs. 12.6, respectively). ConclusionSitus inversus was present in 25% of Japanese PCD patients, which is much lower than observed in other countries. This is a result of differences in the major disease-causing genes. The general rule that “situs inversus is observed in approximately 50% of PCD patients” cannot be applied, at least, in Japanese PCD patients.

Novel compound heterozygous mutations of DNAH5 identified in a pediatric patient with Kartagener syndrome: case report and literature review

BackgroundKartagener syndrome is a subtype of primary ciliary dyskinesia that may exhibit various symptoms including neonatal respiratory distress and frequent infections of the lung, sinus and middle ear because of the impaired function of motile cilia. In addition to typical symptoms of primary ciliary dyskinesia, patients with Kartagener syndrome also show situs inversus. It is an autosomal recessive disorder which is mostly caused by mutations in DNAH5. Kartagener syndrome is often underdiagnosed due to challenges in the diagnosis process. As next-generation sequencing becomes widely used in clinical laboratories, genetic testing provides an accurate approach to the diagnosis of Kartagener syndrome.Case presentationA 7-year-old female patient presented with runny nose of 6 years duration and recurrent cough with phlegm of 2 years duration. Kartagener syndrome was diagnosed through diagnostic tests such as nasal nitric oxide (NO) concentration and transmission electron microscopy, and after performing other exams that corroborated the diagnosis, such as computed tomography, bronchoscopy and hearing test. Whole-exome sequencing was performed for the patient and both parents. The pediatric patient was diagnosed as Kartagener syndrome with the typical symptoms of ciliary dyskinesia including bronchiectasis, sinusitis, conductive hearing loss and situs inversus along with a reduced nasal NO concentration and ciliary abnormalities. The patient carried two novel compound heterozygous mutations in DNAH5, NM_001369:c.12813G > A (p. Trp4271Term) and NM_001369:c.9365delT (p. Leu3122Term). Both mutations lead to premature stop codons and thus are pathogenic. The p. Trp4271Term and p. Leu3122Term mutations were inherited from the father and the mother of the patient individually. A literature review was also conducted to summarize DNAH5 mutations in pediatric patients with Kartagener syndrome across different ethnic groups.ConclusionsOur study provides a good example of the diagnosis of Kartagener syndrome in pediatric patients using a series of diagnostic tests combined with genetic testing. Two novel loss-of-function mutations in DNAH5 were identified and validated in a pediatric patient with Kartagener syndrome.

A Single-Center, Randomized, 3-Way, Crossover Study to Evaluate the Effect of an Exhalation Delivery System on Nasal Nitric Oxide Concentrations in Patients with Chronic Sinusitis

A Single-Center, Randomized, 3-Way, Crossover Study to Evaluate the Effect of an Exhalation Delivery System on Nasal Nitric Oxide Concentrations in Patients with Chronic Sinusitis

The impact of ivacaftor on sinonasal pathology in S1251N-mediated cystic fibrosis patients.

ImportanceSinonasal symptoms in patients suffering from cystic fibrosis can negatively influence the quality of life and sinuses can be a niche for pathogens causing infection and inflammation leading to a decrease of lung function. Ivacaftor, a potentiator of the Cystic Fibrosis Transmembrane Conductance Regulator protein, has shown improvement in pulmonary function in cystic fibrosis patients with different forms of class III gating mutations. However, the effects of ivacaftor on sinonasal pathology have hardly been studied.ObjectiveTo determine the impact of ivacaftor therapy on sinonasal pathology in patients with cystic fibrosis with an S1251N mutation.DesignProspective observational mono-center cohort study, between June 2015 and December 2016.SettingA tertiary referral center in Utrecht, The Netherlands.ParticipantsEight patients with cystic fibrosis with an S1251N mutation, treated with the potentiator ivacaftor were investigated.ExposuresIvacaftor (Kalydeco, VX-770) therapy. Computed tomography imaging of paranasal sinuses. Nasal nitric oxide concentration measurements and nasal endoscopy.Main outcomes and measuresPrimary outcome is opacification of paranasal sinuses examined with computed tomography scan analysis and scaled by the modified Lund-Mackay score before and one year after treatment. Secondary outcomes are nasal nitric oxide concentration levels, sinonasal symptoms and nasal endoscopic findings before and approximately two months and in some cases one year after treatment.ResultsComputed tomography scan analysis showed a significant decrease in opacification of the majority of paranasal sinuses comparing the opacification score per paranasal sinus before and after one year of treatment with ivacaftor. Median nasal nitric oxide levels significantly improved from 220.00 (IQR:136.00–341.18) to 462.84 (IQR:233.17–636.25) (p = 0.017) parts per billion. Likewise, the majority of sinonasal symptoms and nasal endoscopic pathology decreased or resolved at two months after the use of ivacaftor.Conclusion and relevanceIvacaftor appears to improve sinonasal outcome parameters and thereby sinonasal health in patients with cystic fibrosis with an S1251N mutation.

Nasal Nitric Oxide Measurement in Primary Ciliary Dyskinesia. A Technical Paper on Standardized Testing Protocols.

Nasal nitric oxide concentrations are extremely low in primary ciliary dyskinesia (PCD), and measurement of this nasal gas is recommended as a PCD diagnostic test in cooperative patients aged 5 years and older. However, nasal nitric oxide measurements must be performed with chemiluminescence analyzers using a standardized protocol to ensure proper results, because nasal nitric oxide values can be influenced by various internal and external factors. Repeat nasal nitric oxide testing on separate visits is required to ensure that low diagnostic values are persistent and consistent with PCD. This technical paper presents the standard operating procedures for nasal nitric oxide measurement used by the PCD Foundation Clinical and Research Centers Network at various specialty centers across North America. Adherence to this document ensures reliable nasal nitric oxide testing and high diagnostic accuracy when employed in a population with appropriate clinical phenotypes for PCD.

The Clinical Significance of Nasal Nitric Oxide Concentrations in Preschool Children with Nasal Inflammatory Disease

Background: Allergic rhinitis is an allergic inflammation of the nasal airways, and chronic rhinosinusitis is an inflammation of the paranasal sinuses. It can be induced by infection, allergy, or autoimmune problems. Diagnosis of these two diseases is made primarily based on clinical symptoms, allergen test, and imaging. The allergen test is invasive and expensive. The imaging test is harmful to children. Measurement of nasal nitric oxide (NNO) was noninvasive, without radiation, and inexpensive. This study was to evaluate the clinical significance of NNO in preschool children with nasal inflammatory diseases. Methods: A total of 55 cases of allergic rhinitis, including 35 mild cases and 20 moderate to severe cases, and 33 cases of chronic rhinosinusitis, including 18 mild cases and 15 moderate to severe cases were selected as the experimental group. Fifty healthy preschool children were chosen as the control group. The levels of NNO in all children were measured. The differences in the levels of NNO among allergic rhinitis, chronic rhinosinusitis, and the control group were compared. The levels of NNO in the control group were also analyzed. Results: The levels of NNO were significantly higher in preschool children with allergic rhinitis than in the control group, and the differences were significant. However, the levels of NNO in preschool children with chronic rhinosinusitis were lower than in the control group. In the control group, the levels of NNO were not significantly different between genders, and no significant correlation between NNO levels and the children’s height was found. Conclusion: As a noninvasive method for detecting nasal inflammatory diseases, measuring the levels of NNO had a high clinical significance in preschool children.

Efficacy of lianhuaqingwen granules in the management of chronic rhinosinusitis without nasal polyps.

Chronic rhinosinusitis (CRS) is a complicated disease with clinical symptoms that are impacted by the absence or presence of nasal polyps (CRSsNP or CRSwNP). Understanding of the different treatments of CRS is very significant in selecting appropriate therapies and preventing exacerbation relevant to this chronic inflammation. This study was aimed to evaluate the effect of Chinese traditional medicine lianhuaqingwen granules on CRSsNP. CRSsNP patients were enrolled and randomized into placebo or lianhuaqingwen (LHQW) granules treatment group (placebo or LHQW group). Their clinical symptoms were scored using Visual Analog Scale (VAS) and Sino-Nasal Outcome Test (SNOT)-22. Nitric oxide (NO) from nasal cavity and sinus and nasal resistance were also examined. Then, nasal biopsy samples and nasal lavage fluid (NLF) were obtained from these patients, and histologic characteristics of nasal mucosa and T cell subpopulations patterns in the NLF were evaluated. Finally, inflammatory mediators in the NLF were assessed in both groups. One hundred and forty patients with CRSsNP finished this one-month study. VAS and SNOT-22 scores and nasal resistance were all decreased distinctly after the treatment of LHQW, but not after placebo. However, the nasal NO concentration was increased in LHQW administration group in comparison with placebo group. There were significant differences in above parameters between these two treatments. Histologic changes in nasal mucosa were improved only in LHQW group. CD4+ and CD8+ T cells were all downregulated in the LHQW treatment group, but not in placebo group. Inflammatory mediators from the NLF were decreased in LHQW treatment group compared to placebo group. Furthermore, there were significant changes between these two groups in CD4+ and CD8+ T cell subpopulations and concentrations of inflammatory substances. These findings demonstrate that LHQW granules treatment may control the inflammation in nasal mucosa and result in the improvement of CRSsNP. This Chinese medicine might become a promising therapy in the management of this disease.

Mice with a Deletion of Rsph1 Exhibit a Low Level of Mucociliary Clearance and Develop a Primary Ciliary Dyskinesia Phenotype.

Primary ciliary dyskinesia (PCD) is a genetically and phenotypically heterogeneous disease caused by mutations in over 40 different genes. Individuals with PCD caused by mutations in RSPH1 (radial spoke head 1 homolog) have been reported to have a milder phenotype than other individuals with PCD, as evidenced by a lower incidence of neonatal respiratory distress, higher nasal nitric oxide concentrations, and better lung function. To better understand genotype-phenotype relationships in PCD, we have characterized a mutant mouse model with a deletion of Rsph1. Approximately 50% of cilia from Rsph1-/- cells appeared normal by transmission EM, whereas the remaining cilia revealed a range of defects, primarily transpositions or a missing central pair. Ciliary beat frequency in Rsph1-/- cells was significantly lower than in control cells (20.2 ± 0.8 vs. 25.0 ± 0.9 Hz), and the cilia exhibited an aberrant rotational waveform. Young Rsph1-/- animals demonstrated a low rate of mucociliary clearance in the nasopharynx that was reduced to zero by about 1 month of age. Rsph1-/- animals accumulated mucus in the nasal cavity but had a lower bacterial burden than animals with a deletion of dynein axonemal intermediate chain 1 (Dnaic1-/-). Thus, Rsph1-/- mice display a PCD phenotype similar to but less severe than that observed in Dnaic1-/- mice, similar to what has been observed in humans. The results suggest that some individuals with PCD may not have a complete loss of mucociliary clearance and further suggest that early diagnosis and intervention may be important to maintain this low amount of clearance.

Adjuvant electrostimulation therapy for chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is one of the most common chronic diseases in Germany and is often accompanied by years of chronic rhinosinusitis. According to the current German guideline "Rhinosinusitis", the nasal application of salt solutions, topical corticosteroids and in individual cases also systemic corticosteroids appear useful for a symptomatic therapy of CRS. The evidence for other therapeutic procedures such as acupuncture, homeopathy and phytotherapeutics is seen as insufficient. The aim of the present study was to investigate whether anti-inflammatory effects of electrostimulation therapy can also be demonstrated in CRS. randomized, prospective single center study, primary setting; 16 patients with moderate chronic rhinosinusitis with polyps (cRScNP), corresponding to a Lund / Mackay score of 6-12; home based electrostimulation therapy (EST) with amplitude modulated current (base frequency of 4000 Hz, frequency band of 100-250 Hz) over 2 weeks adjuvant to a concurrent sinusitis therapy with topical corticosteroids; measurement of nasal nitric oxide concentration and self-assessment of complaints with the questionnaire instrument SNOT-20 GAV; survey points t0 before EST, t1 after EST, t2 6 weeks after t1. Home based EST was performed by 16 patients. The results indicate that the positive effects of electrostimulation therapy in inflammatory processes also exist in CRS. Adjuvant transsinuidal electrostimulation could thus enrich the conservative therapy of CRS. Further studies with larger collectives are desirable.

Numerical study on nitric oxide transport in human nasal airways

Any slight clinical problem in the nasal system may result in inconveniences in our daily lives, being related with respiratory ventilation and nitric oxide (NO) concentration in the respiratory air. It is known that NO is produced and absorbed by the mucosal layer, especially in the nasal system and its concentration is upregulated or downregulated along with nasal inconveniences or nasal deformities. This study numerically investigates the air flows and the transport of gaseous NO in the human nasal system comprising nasal cavity and paranasal sinuses in order to understand the relations among nasal air flow rates, NO concentrations, and nasal structures. Using commercial mesh generation and fluid dynamics simulation codes, we predicted flow fields in the nasal system according to respiration volumes flowing through nasal cavity and entrance diameters of maxillary sinus. Three dimensional simulations with sinusoidal respiratory flow rates show that NO concentrations in frontal sinus are greater than 10000 ppb that are considerably higher than those in other systems, since the former has only one ostium of small diameter while other systems have two gateways of nasal air flowing in and out. Therefore, major mechanism for NO transportation in the former is diffusion, while those in the latter are both convection and diffusion. Concentrations of NO exhaled from nasal cavity are less than 100 ppb and those in maxillary sinus are greater than 2000 ppb, which agree well with experimental observations available in literature.

Sleep-disordered breathing children: Measurement of nasal nitric oxide and fractional exhaled nitric oxide.

To assess the clinical significance of nasal nitric oxide (nNO) and fractional exhaled nitric oxide (FeNO) concentrations in children with sleep-disordered breathing (SDB). Enrolled in this study were 30 children with SDB and 15 healthy children. The nNO and FeNO concentrations were measured noninvasively using a NIOX MINO system (Aerocrine AB, Solna, Sweden). SPSS statistics 20.0 software (IBM SPSS statistics 20.0, Armonk, NY, USA) was used to analyze the data. The median (25th and 75th percentiles) nNO concentration of SDB children measured in parts per billion (ppb) was 111.0 (44.0; 349.0) ppb; FeNO concentration of SDB children was 12.0 (9.8; 14.0) ppb. The nNO concentration of healthy children was 52.0 (22.0; 139.0) ppb; FeNO concentration of healthy children was 12.0 (10.0; 16.0) ppb. Compared to healthy children, nNO concentration was significantly higher in children with SDB (Z = -2.215, P = 0.027). Correlation analysis showed that SDB children's nNO concentration directly correlated with apnea-hypopnea index (AHI; r = 0.429, P = 0.018), and inversely correlated with nadir oxygen saturation (SaO2; r = -0.482, P = 0.007). No other polysomnographic parameters significantly correlated with nNO concentration. Our data suggest that nNO concentration might be useful for diagnosis and evaluation of disease severity in SDB children. Furthermore, these results suggest that nNO concentration has a greater prognostic value than FeNO concentration.

Recent advances in primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a genetic disease inherited in an autosomal recessive manner. The prevalence of PCD is estimated to be 1 in 20,000 live births. Congenital abnormality of the primary cilia results in situs inversus in 50% of patients. Decreased function of motile cilia causes chronic rhinosinusitis, otitis media with effusion, bronchiectasis and infertility. Cases with situs inversus are considered to show "Kartagener's syndrome", and diagnosis is not difficult. However, in cases without situs inversus, the diagnosis is much more troublesome. PCD without situs inversus is thus probably underdiagnosed. Prolonged chronic cough represents an important symptom that is seen in most patients. The diagnosis of PCD requires the presence of the characteristic clinical phenotypes and either: (1) specific ciliary ultrastructural defects identified by transmission electron microscopy in biopsy samples of respiratory epithelium; or (2) identification of mutation in one of the genes known to be associated with PCD. Nasal nitric oxide concentration is extremely low in PCD, and this could be useful for screening of the disease. At present, no fundamental therapies are available for PCD. Diagnosis in the early stages is important to prevent progression of bronchiectasis and deterioration of lung function by guidance for daily life, immunization, cessation of smoking and prompt therapy at the time of respiratory tract infection. Since PCD is inherited in an autosomal-recessive manner, genetic counseling is necessary after definite diagnosis.

Measurement of nasal and fractional exhaled nitric oxide in children with upper airway inflammatory disease: Preliminary results

ObjectivesTo assess the clinical significance of nasal nitric oxide (nNO) and fractional exhaled nitric oxide (FeNO) concentrations in children with upper airway inflammatory disease. MethodsFifteen healthy children, 30 with allergic rhinitis (AR), 10 with non-allergic rhinitis (NAR), and 30 with sleep disordered breathing (SDB) were enrolled. The FeNO and nNO concentrations were measured non-invasively using a NIOX MINO system. ResultsBoth nNO and FeNO were significantly higher in children with AR than in healthy children (P=0.000 and P=0.000, respectively). Compared to healthy children, nNO was also significant higher in children with NAR (P=0.011) or SDB (P=0.027). In contrast, FeNO did not differ from controls in children with NAR or SDB. ConclusionsOur data suggest that nNO has potential value for diagnosing upper airway inflammation. Moreover, elevated FeNO distinguishes allergic from non-allergic rhinitis.