Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology

Mind-Body Therapies in the Management of Otolaryngologic Disease: A State-of-the-Art Review of Randomized Controlled Trials

OBJECTIVE

To review and assess the peer-reviewed literature on the utility of mind-body therapy (MBT) as an adjunct treatment in the management of otolaryngologic disease.

DATA SOURCES

PubMed, Embase, and Cochrane.

REVIEW METHODS

Randomized control trials (RCTs) of MBTs in the management of otolaryngologic disease from 2002 to 2022 were identified and included according to predefined criteria. Interventions requiring expensive equipment were excluded because the goal of MBT is to be cost-conscious. All studies were subjected to a two-stage blinded screening, extraction, and appraisal process. The outcomes of the intervention and control groups were compared.

CONCLUSION

RCTs of MBTs, including breathing exercises (4), aromatherapy (2), biofeedback (2), meditation, (2), and yoga (2), have been studied in several otolaryngologic conditions, including septoplasty/rhinoplasty (3), head and neck cancer (2), facial palsy (2), and tinnitus (2). Most studies were of moderate risk of bias on appraisal, and each MBT studied was found to significantly reduce subjective and objective distress associated with the otolaryngologic condition in question.

IMPLICATIONS FOR PRACTICE

Despite a paucity of strong evidence supporting the universal use of MBTs, our review suggests that MBTs are cost-effective and easily deployable complementary tools in the management of otolaryngologic disease. Future large, methodologically rigorous RCTs are needed to address the limitations of the included studies, such as improper blinding and inappropriate statistical analysis. As MBTs are studied further, a case for their current use can be made because of their low cost and minimal risk to patients.

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

BACKGROUND

In 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.

METHODS

A 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.

RESULTS

The 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.

CONCLUSIONS

The 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.

Plasma Asymmetrıc Dımethylargınıne (ADMA) and Nıtrıc Oxıde (NO) Levels ın Patıents wıth Chronıc Pansınusıtıs

Chronic pansinusitis is a mucosal inflammation of the nose and all paranasal sinuses with severe inflammation of the upper airways. Asymmetric dimethylarginine (ADMA) is associated with oxidative stress. In this study, we aimed to examine the plasma levels and importance of ADMA and nitric oxide (NO) in patients with chronic pansinusitis. The study was conducted with a total of 64 patients. The study group included a total of 40 patients with chronic pansinusitis. (18 females, 22 males) (mean age 32.27 ± 10.02). The control group consisted of 24 patients (11 females and 13 males). The mean age of the patients in the control group was 31.35 ± 6.05 years. Nasal endoscopic examinations were performed in patients with a history of chronic pansinusitis and symptoms of chronic pansinusitis. Later, the diagnosis of chronic pansinusitis was confirmed with coronal paranasal sinus Computed tomography scans. Plasma ADMA levels were measured by ELISA method and NO levels were measured by Griess method. Plasma ADMA and NO levels of the patients and healthy volunteers were measured and the mean plasma levels of the two groups were compared. ADMA levels were significantly higher in the group with chronic pansinusitis compared to the control group (1.23 ± 0.41 μM and 0.28 ± 0.06 μM, respectively) (p < 0.001), while NO levels were significantly lower in the patient group compared to the control group (7.06 ± 1.07 μM and 12.25 ± 0.95, μM, respectively) (p < 0.001). Our results show that the increase in ADMA levels and the decrease in NO levels are associated with chronic pansinusitis. According to these results, increased plasma levels of ADMA in chronic pansinusitis may be useful in clinical use as a sign of increased oxidative stress.

In healthy subjects nasal nitric oxide does not correlate with olfactory sensitivity, trigeminal sensitivity, and nasal airflow

OBJECTIVE

The aim of the study was to determine the relationship between nasal nitric oxide (nNO) and olfactory sensitivity, trigeminal sensitivity and nasal airflow in healthy subjects.

STUDY DESIGN

This is a correlational study.

SETTING

This study was carried out in a tertiary referral centre.

PARTICIPANTS

Forty healthy participants were recruited.

MAIN OUTCOME MEASURES

nNO was measured using a chemiluminescence analyser (Niox Vero^® , Circassia AB, Uppsala, Sweden), olfactory sensitivity was determined using phenyl ethyl alcohol odour thresholds using the 'Sniffin' Sticks', trigeminal sensitivity was assessed with carbon dioxide delivered by an automated device, and nasal airflow was measured using the peak nasal inspiratory flow (PNIF).

RESULTS

The median nNO was 518 ppb (IQR =333) in the right nostril, and it was 567 ppb (IQR = 314) in the left nostril. The median odour threshold was 7.1 (IQR = 4.4), the median CO₂ threshold was 919 ms (IQR = 1297) and the mean PNIF was 108 L/min (SEM = 4.9). nNO did not correlate significantly with odour threshold, CO₂ threshold or PNIF (Spearman's |ρ|  <0.15, p > .18).

CONCLUSION

In healthy subjects, nNO does not appear to be associated with olfactory sensitivity, trigeminal sensitivity and PNIF.

[Radicality of maxillary sinus surgery and size of the maxillary sinus ostium]

Until the 1990s, radical sinus surgery was considered a standard procedure for maxillary sinus diseases, but it is no longer favored due to the high morbidity. Today, functional endoscopic sinus surgery (FESS) is considered the gold standard in sinus surgery. Modifications of surgical approaches also allow access to regions of the maxillary sinus that were previously difficult to reach. Depending on anatomy and pathology, different methods for widening the maxillary ostium can be selected. In type I sinusotomy, the natural ostium is widened dorsally by a maximum of 1 cm. Sinusotomy type II involves widening the natural ostium up to a maximum diameter of 2 cm. In sinusotomy type III, the natural ostium is widened dorsally to the posterior wall of the maxillary sinus and caudally to the base of the inferior turbinate. Beside the prelacrimal approach, more invasive approaches are the medial maxillectomy, in which the dorsal part of the inferior turbinate and the adjacent medial wall of the maxillary sinus is resected, as well as its modifications "mega antrostomy" and "extended maxillary antrostomy." Correct selection of the size of the maxillary sinus window is prerequisite for successful treatment and long-term postoperative success. Isolated purulent maxillary sinusitis can usually be treated by a type I sinusotomy. Sinusotomy type II addresses nasal polyps with involvement of the mucosa of the ostium, recurrent stenosis after previous surgery, chronic maxillary sinusitis due to cystic fibrosis, and purulent maxillary sinusitis with involvement of other adjacent sinuses. Sinusotomy type III is required for choanal polyps with attachment to the floor of the maxillary sinus, for extensive polyposis and fungal sinusitis, and for inverted papilloma. Particularly for (recurrent) disease and extensive interventions in the maxillary sinus, medial maxillectomy or a modification thereof may be required.

Inflammation, infection, and allergy of upper airways: new insights from national and real-world studies

The upper airways (UA) should be considered as a functional unit. Current functional anatomy divides URT in three, mutually dependent, "junction boxes": i) the ostio-meatal complex (OMC), ii) the spheno-ethmoidal recess (SER), and iii) the rhinopharynx (RP). Correct ventilation and effective mucociliary clearance of these sites significantly affect the healthy physiology of the entire respiratory system. The OMC, SER, and RP obstruction is the first pathogenic step in the inflammatory/infectious cascade of UA disorders. The inflammation of the respiratory mucosa is the main pathogenic factor for airway obstruction. Moreover, bacterial biofilm (a strategy modality of bacterial survival) is an important local cause of systemic antibiotic ineffectiveness, recurrent infections, and antibiotic resistance. Health microbiota guarantees UA wellness; on the contrary, dysbiosis promotes and worsens UA infections. Allergy, namely type 2 inflammation, is a common cause of UA obstruction such as promoting in turn infections. Fiberoptic endoscopy is a mandatory diagnostic tool in clinical practice. Nasal cytology, mainly concerning flow cytometry, allows defining rhinitis phenotypes so allowing a precision medicine approach. Several conventional therapeutic approaches are available, but efficacy and safety should be ever properly considered before the prescription. Also, complementary medicine plays a fruitful role in the management of UA diseases. National and real-world studies are reported and discussed as they may be useful in daily clinical practice.

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

OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Inflammatory Biomarkers During Bacterial Acute Rhinosinusitis

PURPOSE OF REVIEW

Diagnosis of bacterial acute rhinosinusitis is difficult. Several attempts have been made to clarify the diagnostic criteria. Inflammatory biomarkers are easily obtainable variables that could shed light on both the pathophysiology and diagnosis of bacterial acute rhinosinusitis. The purpose of this review article is to assess literature concerning the course of inflammatory biomarkers during acute rhinosinusitis and the use of inflammatory biomarkers in diagnosing bacterial acute rhinosinusitis.

RECENT FINDINGS

We included C-reactive protein, erythrocyte sedimentation rate, white blood cell counts, procalcitonin, and nasal nitric oxide in this review and found that especially elevated C-reactive protein and erythrocyte sedimentation rate are related to a higher probability of a bacterial cause of acute rhinosinusitis. Still, normal levels of these two biomarkers are quite common as well, or the levels can be heightened even during viral respiratory infection without suspicion of bacterial involvement. Elevated levels of C-reactive protein or erythrocyte sedimentation rate support diagnosis of bacterial acute rhinosinusitis, but due to a lack of sensitivity, they should not be used to screen patients for bacterial acute rhinosinusitis.

Xylitol nasal irrigation in the treatment of chronic rhinosinusitis

OBJECTIVE

To evaluate the efficacy of xylitol nasal irrigation (XNI) treatment on chronic rhinosinusitis (CRS) and to investigate the effect of XNI on nasal nitric oxide (NO) and inducible nitric oxide synthase (iNOS) mRNA in maxillary sinus.

MATERIALS AND METHODS

Patients with CRS were enrolled and symptoms were assessed by Visual Analog Scale (VAS) and Sino-Nasal Outcome Test 22 (SNOT-22). Nasal NO and iNOS mRNA in the right maxillary sinus were also examined. Then, they were treated with XNI (XNI group) or saline nasal irrigation (SNI, SNI group) for 30days, after which their symptoms were reassessed using VAS and SNOT-22, and nasal NO and iNOS mRNA in the right maxillary sinus were also reexamined.

RESULTS

Twenty-five out of 30 patients completed this study. The scores of VAS and SNOT-22 were all reduced significantly after XNI treatment, but not after SNI. The concentrations of nasal NO and iNOS mRNA in the right maxillary sinus were increased significantly in XNI group. However, significant changes were not found after SNI treatment. Furthermore, there were statistical differences in the assessments of VAS and SNOT-22 and the contents of nasal NO and iNOS mRNA in the right maxillary sinus between two groups.

CONCLUSIONS

XNI results in greater improvement of symptoms of CRS and greater enhancement of nasal NO and iNOS mRNA in maxillary sinus as compared to SNI.

Comparison of nasal nitric oxide levels between the inferior turbinate surface and the middle meatus in patients with symptomatic allergic rhinitis

BACKGROUND

Because of the anatomical complexity and the high output of the human nose, it has been unclear whether nasal nitric oxide (NO) serves as a reliable marker of allergic rhinitis (AR). We examined whether nasal NO levels in the inferior turbinate (IT) surface and the middle meatus (MM) differ in symptomatic AR patients.

METHODS

We measured fractional exhaled NO (FeNO) and nasal NO in normal subjects (n = 50) and AR patients with mild symptoms (n = 16) or moderate or severe symptoms (n = 27). Nasal NO measurements were obtained using an electrochemical analyzer connected to a catheter and an air-suction pump (flow rate 50mL/sec).

RESULTS

Compared to the normal subjects, the AR patients showed significantly higher nasal FeNO and nasal NO levels in the IT area. No significant difference in the MM area was observed among the three groups. The MM area showed higher NO levels than the IT area in all three groups. The ratio of nasal NO levels of the MM area to the IT area (MM/IT ratio) was significantly lower in the AR groups. The moderate/severe AR patients showed significantly higher nasal NO in the IT area (104.4 vs. 66.2ppb) and lower MM/IT ratios than those in the mild AR patients. The analysis of nasal brushing cells revealed significantly higher eosinophil cationic protein and nitrotyrosine levels in the AR groups.

CONCLUSIONS

Nasal NO assessment in the IT area directly reflects persistent eosinophilic inflammation and may be a valid marker to estimate the severity of AR.

Corticosteroid use does not alter nasal mucus glucose in chronic rhinosinusitis

OBJECTIVES

To evaluate nasal mucus glucose concentrations in patients with and without chronic rhinosinusitis and determine if corticosteroid therapy alters mucus glucose.

STUDY DESIGN

Prospective observational study.

SETTING

Single tertiary care center.

SUBJECTS

Ninety-five patients presenting to an otolaryngology clinic.

METHODS

Participants completed questionnaires that included a history of medical and surgical therapies as well as sinusitis-specific quality-of-life measurements. Nasal mucus was collected in an outpatient clinic using an open cell foam technique. The nasal mucus glucose concentrations of patients with and without chronic rhinosinusitis were compared to the use of systemic and topical glucocorticoid treatment.

RESULTS

A statistically significant difference was measured between mean nasal glucose secretions of control patients, 10.2 mg/dL, compared with patients diagnosed with chronic rhinosinusitis, 18.4 mg/dL (P < .0001). Use of corticosteroids, both topical and systemic, did not correlate with nasal glucose concentrations.

CONCLUSION

Patients diagnosed with chronic rhinosinusitis have elevated nasal glucose concentrations compared with control patients, and this elevated nasal glucose level was independent of corticosteroid use. Nasal glucose may independently contribute to the pathophysiology of chronic rhinosinusitis.

The effect of high altitude on nasal nitric oxide levels

The aim of the present study was to investigate whether nasal nitric oxide (nNO) levels change in relation to high altitude in a natural setting where the weather conditions were favorable. The present study included 41 healthy volunteers without a history of acute rhinosinusitis within 3 weeks and nasal polyposis. The study group consisted of 31 males (76 %) and 10 females (24 %) and the mean age of the study population was 38 ± 10 years. The volunteers encamped for 2 days in a mountain village at an altitude of 1,500 m above sea level (masl) and proceeded to highlands at an altitude of 2,200 masl throughout the day. The measurements of nNO were done randomly, either first at the mountain village or at sea level. Each participant had nNO values both at sea level and at high altitude at the end of the study. The nNO values of sea level and high altitude were compared to investigate the effect of high altitude on nNO levels. The mean of average nNO measurements at the high altitude was 74.2 ± 41 parts-per-billion (ppb) and the mean of the measurements at sea level was 93.4 ± 45 ppb. The change in nNO depending on the altitude level was statistically significant (p < 0.001). The current investigation showed that nNO levels were decreased at high altitude even if the weather conditions were favorable, such as temperature, humidity, and wind.

The Staphylococcus aureus SrrAB two-component system promotes resistance to nitrosative stress and hypoxia

Staphylococcus aureus is both a commensal and a pathogen of the human host. Survival in the host environment requires resistance to host-derived nitric oxide (NO·). However, S. aureus lacks the NO·-sensing transcriptional regulator NsrR that is used by many bacteria to sense and respond to NO·. In this study, we show that S. aureus is able to sense and respond to both NO· and hypoxia by means of the SrrAB two-component system (TCS). Analysis of the S. aureus transcriptome during nitrosative stress demonstrates the expression of SrrAB-dependent genes required for cytochrome biosynthesis and assembly (qoxABCD, cydAB, hemABCX), anaerobic metabolism (pflAB, adhE, nrdDG), iron-sulfur cluster repair (scdA), and NO· detoxification (hmp). Targeted mutations in SrrAB-regulated loci show that hmp and qoxABCD are required for NO· resistance, whereas nrdDG is specifically required for anaerobic growth. We also show that SrrAB is required for survival in static biofilms, most likely due to oxygen limitation. Activation by hypoxia, NO·, or a qoxABCD quinol oxidase mutation suggests that the SrrAB TCS senses impaired electron flow in the electron transport chain rather than directly interacting with NO· in the manner of NsrR. Nevertheless, like NsrR, SrrAB achieves the physiological goals of selectively expressing hmp in the presence of NO· and minimizing the potential for Fenton chemistry. Activation of the SrrAB regulon allows S. aureus to maintain energy production and essential biosynthetic processes, repair damage, and detoxify NO· in diverse host environments.

The Hmp flavohemoglobin is required for nitric oxide resistance and is widely distributed in bacteria. Hmp expression must be tightly regulated, because expression under aerobic conditions in the absence of nitric oxide can exacerbate oxidative stress. In most organisms, hmp expression is controlled by the Fe-S cluster-containing repressor NsrR, but this transcriptional regulator is absent in the human pathogen Staphylococcus aureus. We show here that S. aureus achieves hmp regulation in response to nitric oxide and oxygen limitation by placing it under the control of the SrrAB two-component system, which senses reduced electron flow through the respiratory chain. This provides a striking example of convergent evolution, in which the common physiological goals of responding to nitrosative stress while minimizing Fenton chemistry are achieved by distinct regulatory mechanisms.

Paranasal sinus nitric oxide and migraine: a new hypothesis on the sino rhinogenic theory

Migraine is a debilitating illness that has no exact bio molecule to explain its pathology. After reviewing the neurophysiological and biochemical basis of the research findings of nitric oxide and migraine, I present to the best of my knowledge the first para sinus nitric oxide mediated neurobiophysiological hypothesis for migraine of sino rhinogenic origin. The diffused paranasal sinus nitric oxide in the nasal mucosa could be the primary molecule that initiates migraine and is termed Sinus Hypoxic Nitric Oxide Theory. This hypothesis regards repetitive or intermittent activation of the trigeminal sensory nerve and blood vessels in the nasal mucosa. Production of paranasal sinus nitric oxide is mainly induced by hypoxia due to several independent factors and the diffusion of paranasal sinus nitric oxide depends on the vulnerable surface area in the nasal cavity. Apart from the known trigeminal nociceptive impulse in the migraine, two main peripheral trigeminal nerve activating mechanisms may induce migraine. First the nerve endings of the nasal mucosa which are directly stimulated by diffused paranasal sinus nitric oxide are indirectly stimulated by vasoactive substances released by antidromic activation of the nerve, parasympathetic efferent of the nerve and sterile neurogenic inflammation. Secondly, the perivascular nerve of nasal mucosal and the meningial blood vessels are directly stimulated by either diffused paranasal sinus nitric oxide or by shear stress mediation. The nerve impulses of the trigeminal sensory nerve, projected at trigeminal nucleus caudalis to the central nerve system and low plasma magnesium due to the consequence of shear stress gives rise to the symptoms of migraine. Moreover sino rhinogenic impulses may mediate to disruption of inhibitory sensitization modulated of sensory input and cause sensory hiperexcitability. In addition neuronal stimulation proposed by some migraine hypotheses could also give rise to migraine headache when the sino rhinogenic vulnerable factors induce the migraine pathophysiology. Indeed this article explains a new pathophysiological initiation between sino rhinogenic nitric oxide effects and migraine and provides an initial step for the obscured or neglected etiologically important neuro vascular impulse generating pathway. The patients who are clinically suspected of having headaches should receive comprehensive sino rhinological examination and evaluation based on the sinus hypoxic nitric oxide theory. A standard surgical and medical management of migraine that links with the sinus hypoxic nitric oxide theory may restore the hypoxic state or reduce or remove the paranasal sinus nitric oxide diffusing surface. It warrants clinical testing.

Nasal drug delivery devices: characteristics and performance in a clinical perspective-a review

Nasal delivery is the logical choice for topical treatment of local diseases in the nose and paranasal sinuses such as allergic and non-allergic rhinitis and sinusitis. The nose is also considered an attractive route for needle-free vaccination and for systemic drug delivery, especially when rapid absorption and effect are desired. In addition, nasal delivery may help address issues related to poor bioavailability, slow absorption, drug degradation, and adverse events in the gastrointestinal tract and avoids the first-pass metabolism in the liver. However, when considering nasal delivery devices and mechanisms, it is important to keep in mind that the prime purpose of the nasal airway is to protect the delicate lungs from hazardous exposures, not to serve as a delivery route for drugs and vaccines. The narrow nasal valve and the complex convoluted nasal geometry with its dynamic cyclic physiological changes provide efficient filtration and conditioning of the inspired air, enhance olfaction, and optimize gas exchange and fluid retention during exhalation. However, the potential hurdles these functional features impose on efficient nasal drug delivery are often ignored. With this background, the advantages and limitations of existing and emerging nasal delivery devices and dispersion technologies are reviewed with focus on their clinical performance. The role and limitations of the in vitro testing in the FDA guidance for nasal spray pumps and pressurized aerosols (pressurized metered-dose inhalers) with local action are discussed. Moreover, the predictive value and clinical utility of nasal cast studies and computer simulations of nasal airflow and deposition with computer fluid dynamics software are briefly discussed. New and emerging delivery technologies and devices with emphasis on Bi-Directional™ delivery, a novel concept for nasal delivery that can be adapted to a variety of dispersion technologies, are described in more depth.

Inducible nitric oxide synthase plays important roles in allergic reactions of pollinosis in mice sensitized with pollen allergy

To elucidate the possible involvement of nitric oxide (NO) derived from inducible NO-synthase (iNOS) in the pathogenesis of patients with allergic rhinitis, we analyzed changes in the frequency of sneezing, plasma levels of NO metabolites, α-melanocyte-stimulating hormone (MSH) and immunoglobulin E and tracheal expression of IgA and mast cell tryptase in control and iNOS^−/− mice. Eight-week-old control and iNOS^−/− male C57BL/6j mice were sensitized with Cry j I antigen. After the last intranasal challenge of antigen, changes in the frequency of sneezing and plasma levels of IgE, α-MSH and NO metabolites and tracheal expression of iNOS, IgA and mast cell tryptase were analyzed by ELISA and immunohistochemistry using specific antibodies. The sensitization of mice with Cry j I antigen increased plasma levels of NO metabolites, α-MSH and IgE and tracheal expression of iNOS, IgA and mast cell tryptase in control not but in iNOS^−/− mice. Administration of N^G-nitro-L-arginine methyl ester strongly inhibited all these changes occurred in control mice. These results indicate that the symptom of pollinosis including sneezing is enhanced by iNOS derived NO through activation of α-MSH-receptor containing mast cells enriched with tryptase.

Two patterns of changes in nasal nitric oxide after lysine aspirin nasal challenge in patients with aspirin-exacerbated respiratory disease

BACKGROUND

Nasal nitric oxide (nNO) levels after nasal lysine acetylsalicylic acid (lys-ASA) challenge have not been determined. This study was designed to determine a pattern of changes after lys-ASA challenge in aspirin-exacerbated respiratory disease (AERD) patients and to evaluate the usefulness of nNO measurements in the assessment of lys-ASA nasal challenge outcome.

METHODS

Eighteen patients with aspirin hypersensitivity, nasal polyps, and asthma were included. Aspirin-tolerant control groups consisted of 10 healthy volunteers without asthma and nasal polyps and 10 patients with nasal polyps without asthma. All subjects underwent nasal challenge with lys-ASA. nNO was measured before and 1, 2, 4, and 24 hours after control solution and lys-ASA administration.

RESULTS

A significant fall in nNO levels was noted in AERD patients with a positive result to challenges at time points 1 hour (p = 0.0033), 2 hours (p = 0.0033), and 3 hours (p = 0.026) after lys-ASA. A trend toward higher nNO concentrations was observed after lys-ASA challenge at the 2-hour (p = 0.018) and 4-hour (p = 0.018) time points compared with baseline in subjects with AERD and a clinically negative result to the challenge. No significant changes in nNO levels after the challenge were observed in control groups. The combined increase and decrease in nNO levels gave the sensitivity as 0.94 and specificity 1.00 at best.

CONCLUSION

nNO levels decrease after lys-ASA nasal challenge in subjects with AERD and a clinically positive result of the challenge. An unexpected trend toward an increase in nNO levels is observed in subjects with AERD and a clinically negative result of the challenge.

Effects of nitric oxide in mucociliary transport

The airways are made up of ciliated epithelium which secretes mucous, protecting the respiratory tract from particles inhaled during breathing. Its is paramount to understand the physiology and the mechanisms involved in mucociliary activity. Literature suggests that Nitric oxide (NO), especially the one produced by iNOS expression, maintains the mucociliary function and the immune defense of the nasal cavity.

Aim

to assess NO participation and the enzymatic pathways in the production of NO and mucociliary transport, using constructive and inductive NO synthetase inhibitors, L-NAME and aminoguanidine, respectively.

Materials and methods

frog palates were prepared and immerse in ringer (control), L-NAME or aminoguanidine solutions. The palates were immerse in these solutions for four periods of 15 minutes. Mucociliary transport measures were carried out before and after each exposure.

Results

control palates maintained stable their transportation speed. L-NAME increased, while aminoguanidine reduced mucous transportation velocity.

Conclusion

unspecific cNOS block with L-NAME and relatively specific iNOS block with aminoguanidine results leads us to propose that depending on the pathway, the NO can increase or reduce mucociliary transport in frog palates.

Ventilator-Associated Pneumonia

The area of the alveolar epithelium of the lung is approximately 70 m². This area is constantly in contact with the ambient air and is therefore vulnerable to contamination with airborne microbes and particles of respirable size. Due to the configuration of the respiratory tract, airborne particles having diameters in the range of 0.5-2.0 μ can reach and deposit in the terminal part of the tracheobronchial tree - most bacteria are of this size. In reality, very few bacteria cause infections by spreading via the airborne route (e.g., mycobacteria, viruses, and legionella). Most bacteria cause pneumonia by first colonizing the upper respiratory tract and later descending into the tracheobronchial tree.

Nitric oxide metabolites as biomarkers for follow-up after chronic rhinosinusitis surgery

BACKGROUND

Nitric oxide (NO) has a variety of effects on the pathophysiology of the nasal cavity and seems to play an important role in inflammation. It is increased in the common cold but decreased in acute and chronic rhinosinusitis (CRS). Exhaled NO increases after endoscopic sinus surgery in CRS. In our previous study we showed that NO metabolite (nitrate and nitrite) levels are increased in the sinus cavity of CRS patients. We hypothesized that NO metabolite levels are increased to normal in the nasal lavage of CRS patients after endoscopic sinus surgery and NO metabolites in the nasal lavage can be used as indicators of the disease status after surgery.

METHODS

This study was performed on 52 patients with CRS who did not respond to medical therapy and who underwent surgery. NO metabolite levels were measured in nasal lavages of the patients before surgery and 2 months after surgery.

RESULTS

NO metabolite levels (mean +/- SEM) were 18.11 +/- 3.08 micromol/L and 35.97 +/- 4.64 micromol/L in nasal lavages of patients before and after surgery, respectively. The levels of NO metabolites were increased significantly (p < 0.01) after surgery in nasal lavages and patients reported significant improvement based on the visual analog scoring after the operation.

CONCLUSION

NO metabolite levels were decreased in nasal lavages of CRS patients and were increased to normal levels after surgery along with improvement of the disease. NO metabolite levels may be used as an indicator for the follow-up of patients after endoscopic sinus surgery.

Greater nasal nitric oxide output during inhalation: effects on air temperature and water content

The nose conditions the temperature and humidity of nasal air, and the nasal mucosal vasculature supplies heat and water for these processes. We hypothesize that nitric oxide (NO) modulates these processes through vasoactive effects on nasal mucosal vasculature. We measured the temperature, humidity and NO concentrations of nasal air during inhalation and exhalation across the nose and calculated net heat, water and NO output before (controls, n=7) and after inhibition of NO synthase by topical l-NAME (N=5) in healthy humans. We found that calculated NO output across the nasal passages is approximately three-fold greater during inhalation (503+/-105 nL/min) compared with exhalation (162+/-56 nL/min). Moreover, topical administration of l-NAME decreased nasal air temperature and humidity conditioning and NO output, but these effects were limited to inhalation. We conclude that nasal NO output is greater during inhalation than exhalation in humans. Our findings also support a role of nasal NO in temperature and humidity conditioning of nasal air.

Olfactory function and nasal nitric oxide

OBJECTIVE

To determine the relationship between nasal nitric oxide (nNO) concentration and its influence on olfactory function.

SETTING

Tertiary otolaryngology care centre.

PARTICIPANTS

Sixty-four patients suffering from chronic rhinosinusitis and 20 healthy subjects participated.

STUDY DESIGN

Prospective study.

OUTCOME MEASURES

The nNO concentration was measured by chemiluminescence and olfactory thresholds were measured with the phenyl ethanol threshold of the Sniffin' Sticks. In chronic rhinosinusitis patients this measure was done preoperatively and 3 months after endoscopic sinus surgery.

RESULTS

Healthy subjects had significantly higher nNO concentrations and better olfactory thresholds compared to the chronic rhinosinusitis patients, both before and after those had undergone sinus surgery. Olfactory thresholds and nNO concentrations remained unchanged after surgery in the chronic rhinosinusitis group. In the chronic rhinosinusitis group, nNO concentrations correlated positively with the olfactory threshold preoperatively (P < 0.0001) and 3 months after surgery (P < 0.05). In the control group, nNO production did not correlate with the olfactory thresholds (P > 0.05).

CONCLUSION

Olfactory function and nNO concentration correlate in chronic rhinosinusitis patients but not in healthy subjects. This suggests that both parameters do rather not directly influence each other but it might be the inflammatory processes found in chronic rhinosinusitis that affects olfaction and nNO. Nasal nitric oxide produced by the paranasal sinuses seems not to directly influence olfactory function.

Autonomic dysfunction, allergy and the upper airway

PURPOSE OF REVIEW

The autonomic nervous system has been implicated in the pathophysiology of chronic upper airway inflammatory disease for decades. We discuss the most recent literature with regard to autonomic nervous system dysfunction and chronic upper airway disease.

RECENT FINDINGS

Recently, state of the art autonomic nervous system testing has demonstrated autonomic nervous system dysfunction in patients with chronic upper airway inflammatory disease. This dysfunction has been characterized as hypoadrenergic.

SUMMARY

Autonomic nervous system dysfunction likely plays a role in chronic upper airway inflammatory disease. Further investigation may lead to a better understanding of the role of autonomic nervous system dysfunction in these disorders and, hence, opportunities for novel therapeutic modalities.

Nitric oxide: a new concept in chronic sinusitis pathogenesis

PURPOSE

Exhaled NO is produced mainly in paranasal sinuses and nasal mucosa. Nasal NO has been suggested to have a variety of effects in nasal cavity. Decreased exhaled NO is found in chronic sinusitis, and NO metabolite levels are increased in animal models of chronic sinusitis, suggesting a role for them in sinusitis pathogenesis. There was no data available on human NO metabolite level.

MATERIALS AND METHODS

We lavaged maxillary sinuses in a control and 2 patient groups. The control group was patients who underwent functional endoscopic sinus surgery (FESS) due to any other reason than chronic sinusitis. The patient groups had chronic rhinosinusitis with and without polyposis who underwent FESS. Maxillary sinuses were lavaged during FESS, and NO metabolites (nitrate and nitrite) were lavaged in the lavage fluid.

RESULTS

Nitric oxide metabolite levels (mean +/- SEM) were 8.085 +/- 1.43 mumol/L in healthy maxillary sinus lavage fluid and 18.04 +/- 3.51 and 16.78 +/- 2.91 mumol/L in chronic rhinosinusitis with and without polyposis, respectively. Lavage fluid of sinuses with chronic sinusitis had elevated levels of NO metabolites, which were significantly higher than the control group. The difference between the chronic sinusitis with and without polyposis groups was not significant.

CONCLUSIONS

Nitric oxide metabolites were significantly higher in maxillary sinuses of patients with chronic sinusitis. Elevated levels of NO and NO metabolites in sinusitis might damage healthy sinus epithelium. NO metabolites may have an important role in sinusitis pathogenesis.

Experimentally induced acute sinusitis and efficacy of vitamin A

CONCLUSIONS

Although antibiotics are the mainstays for treatment of sinusitis, they do not specifically treat tissue damage due to free radicals. We propose that antioxidant, anti-infective, immunomodulator vitamin A may be a useful addition in the management of sinusitis.

OBJECTIVES

Acute sinusitis is one of the most common diseases in humans. Vitamin A is a fat-soluble vitamin and essential for immunity, cellular differentiation, and maintenance of respiratory and gastrointestinal epithelial surfaces, growth, reproduction, and vision. The objective of this study was to investigate the therapeutic role of vitamin A on healing of acute sinusitis.

MATERIALS AND METHODS

This was a prospective controlled animal trial. Experimental sinusitis was induced by blocking the right nose and inoculating Streptococcus pneumoniae into the right maxillary sinuses. Left maxillary sinuses were used as controls. Rabbits were divided in to two groups. At 48 h after inoculation, group I received only parenteral ampicillin-sulbactam (50 mg/kg), group II was treated with parenteral ampicillin-sulbactam (50 mg/kg) and parenteral a dose of 100,000 IU vitamin A in palmitate form. All animals were sacrificed on the 10th day. Mucosal samples were excised from the infected and control sinuses for histopathologic examination, for measurement of activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), and for evaluation of levels of malondialdehyde (MDA) and nitric oxide (NO).

RESULTS

All the infected sinuses displayed signs of inflammation, but there was no statistically significant difference between the study and control groups. In our study, epithelial integrity as well as NO and MDA levels were better in the group receiving both antibiotic and vitamin A than the group receiving antibiotic alone. Nevertheless, SOD activity was significantly increased in the group receiving only antibiotics, compared with the control mucosal SOD activity. There was no difference between the groups as regards CAT and GSH activity.

Short-term and seasonal variations of exhaled and nasal NO in healthy subjects

Nitric oxide (NO) is an important biological mediator with a variety of cellular and tissue functions. Fractional exhaled (FE(NO)) and nasal NO (FN(NO)) are known to be altered in several respiratory tract disease and disorders. However, there are rather few studies into the reproducibility of FE(NO) or FN(NO) measurements in healthy subjects. The aim of this study was to examine both short- and long-term variations of FE(NO) and FN(NO). In addition to intraday, day-to-day and week-to-week variations, the seasonal variation was assessed. The data revealed that FE(NO) and FN(NO) levels were lower in the mornings compared to the afternoon values. There were clinically significant correlations in day-to-day (morning values 121.4+/-37.5 vs. 119.8+/-29.6, r=0.868, P=0.000), week-to-week (morning values 121.4+/-37.5 vs. 128.0+/-32.1, r=0.637, P=0.000) and seasonal (winter 133.5+/-29.7, summer 138.1+/-47.6, autumn 121.4+/-37.5, r=0.624, P=0.000) values of FN(NO). Day-to-day (morning values 14.6+/-6.7 vs. 14.2+/-5.1, r=0.784, P=0.000) week-to-week (morning values 14.6+/-6.7 vs. 15.4+/-7.3, r=0.738, P=0.000) and seasonal (autumn 14.6+/-7.2, winter 16.6+/-6.4, summer 17.4+/-8.0, r=0.709, P=0.000) levels of FE(NO) were also highly reproducible. Serial FE(NO) and FN(NO) measurements can be used in the monitoring of respiratory tract inflammation. Due to the diurnal variation of FE(NO) and FN(NO,) in long-term follow-up the measurements should be performed at the same time of day.

Serum Nitrite/Nitrate and Arginase Levels in Patients with Allergic Rhinitis

Nitric oxide (NO) plays an important role in the regulation of upper respiratory function. Patients with untreated allergic rhinitis (AR) have an increased level of NO in the nasal cavity compared to normal individuals. We aimed to investigate serum levels of arginase and NO metabolites nitrite/nitrate in patients with AR during the symptomatic period. The patient and control groups consisted of 14 males and 12 females (mean age: 29, range: 20-40 years), and 10 males and 10 females (mean age: 27, range: 22-38 years), respectively. Nitrite/nitrate levels were 0.98 +/- 0.33 ng/ml in the patients with AR, and 0.78 +/- 0.26 ng/ml in the control group (p = 0.03). Arginase levels were 28.8 +/- 14.1 ng/ml in the patients with AR, and 20.8 +/- 13.5 ng/ml in the control group. The difference between the groups was statistically insignificant (p = 0.24). Our results support the view that NO plays an important role in the pathogenesis of AR, and NO metabolites may be used as a marker for monitoring the disease activity and therapy.

Effect of aqueous extracts of Ecballium elaterium rich, in the rabbit model of rhinosinusitis

This study was designated to investigate anti-inflammatory effect of aqueous extract of Ecballium elaterium, which is topically applied for treatment of rhinosinusitis as a traditional folk medicine in Turkey. Therapeutic potential of E. elaterium as an anti-inflammatory agent was examined by measurement of NO* metabolites in a rabbit model of rhinosinusitis. The results showed that both activity of NOS enzyme and concentration of NO* metabolites were significantly reduced by topical administration of E. elaterium extract in therapy group as compared to the control. Thus, the data suggest E. elaterium extract may have the potential to be used as anti-inflammation agent, and can be used in the treatment of rhinosinusitis diseases.

Autonomic function and dysfunction of the nose and sinuses

Patients with inflammatory disorders of the upper airway exhibit varying degrees of ANS dysfunction, including the sympathetic, parasympathetic,and sensory components. Current evidence is insufficient with regard to the exact role of ANS dysfunction and its relationship to these disorders.Thus, the interaction of the ANS and sinonasal inflammation deserves further study.

Radiological imaging of inflammatory lesions in the nasal cavity and paranasal sinuses

Paranasal sinus development and pneumatisation variants are described, and rhinosinusitis and different patterns of inflammatory sinonasal diseases are reviewed. Other inflammatory sinonasal diseases, e.g., fungal sinusitis, mucocele, pyocele and sinonasal manifestations in systemic diseases, are briefly described. Computed tomography (CT) is the primary modality in diagnosing and mapping suspected inflammatory sinonasal disease. Magnetic resonance (MR) imaging is complementary to CT if fungal sinusitis, pyocele or malignancy are suspected.

A novel method of measuring gas phase nitric oxide concentration in cell cultures

This is the first report on the measurement of nitric oxide (NO) concentrations in the gas phase in a squamous cell culture. The technique may permit the assessment of NO output under conditions that aim to mimic facets of pathology in relatively inaccessible tissues. The primary aim of this study was to devise a method to detect the NO concentration produced by cell cultures in the gas phase of a culture flask. A secondary aim was to determine whether the effect of hypoxia or radiation on NO production in a human squamous cell carcinoma cell culture would be detectable with this technique. The NO concentration was measured off-line using a rapid-response chemiluminescent analyzer. The gas samples were aspirated from cell culture flasks (i) under normal culture conditions, (ii) under conditions of hypoxia and (iii) following radiation of human head and neck squamous cell carcinoma cell line cultures. Elevated levels of the gas phase NO concentration were consistently obtained from the cell culture flasks using this experimental set-up. Hypoxia and radiation diminished NO production.

A comparison between nitric oxide output in the nose and sinuses: A pilot study in one volunteer

From a study of nitric oxide (NO) output in the nose and sinuses it seems that: (i) the results obtained regarding the regulation of NO output in the nose do not necessarily apply to the sinuses; (ii) the results obtained for one group of sinuses may not apply to another; and (iii) NO output in the sinuses does not behave as one would expect if it serves to protect against infection.A pilot study was undertaken in one subject to determine whether the control of NO output in the nose differs from that in the sinuses.NO output was measured by aspirating different gaseous concentrations of oxygen (and/or carbon dioxide) through the nasal airways or punctured maxillary and frontal sinuses before and after i.v. administration of L-arginine (20 mg/kg). In the absence of gaseous oxygen in the nose or maxillary antrum, the effect of L-arginine on NO output was the same as that in the presence of oxygen. In the frontal sinus, the effect of L-arginine on NO output was blocked by the absence of gaseous oxygen. NO output in the nose and frontal sinus showed similar changes after either i.v. administration of L-arginine or removal of oxygen from the air. NO output in the maxillary antrum was virtually unaffected by either procedure. NO output in the nose was largely unaffected by the gaseous carbon dioxide content but that in the frontal and maxillary sinuses was profoundly inhibited by it. In both sinuses, suppression of NO output by carbon dioxide was countered by oxygen. Alterations in the oxygen or carbon dioxide content of the maxillary antrum did not alter NO output in the frontal sinus, or vice versa. After i.v. infusion of L-arginine, nasal NO output remained elevated for >1 h.

Childhood Parapneumonic Effusions

STUDY OBJECTIVES

Biochemical and inflammatory markers in pleural inflammation were evaluated in pediatric cases of parapneumonic effusions, and interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha concentrations were tested for possible differentiation of the complicated nature of effusions.

PATIENTS

Twenty-eight patients (12 female) who were admitted to Hacettepe University Childrens' Hospital over a 2-year period were included in the study.

MEASUREMENTS

Patients were grouped according to the stage of effusion. Pleural fluid leukocyte count, neutrophil ratio, pH, protein, glucose levels, lactate dehydrogenase (LDH) levels, TNF-alpha levels, IL-8 levels, and nitrite levels were obtained.

RESULTS

Of these patients, 13 had empyema, 10 had complicated parapneumonic effusions (CPEs), and 5 had uncomplicated parapneumonic effusions (UPEs). Protein and glucose levels decreased, leukocyte count, neutrophil ratio, TNF-alpha levels, nitrite levels, and IL-8 levels increased progressively as the stage of the disease progressed. IL-8 levels, but not TNF-alpha and nitrite levels, were statistically different among the groups. IL-8, TNF-alpha, and nitrite levels all correlated positively with each other (all p < or = 0.001), and pH correlated negatively with these markers (all p < or = 0.001). At a cutoff value of 76.6 pg/mL, TNF-alpha discriminated between CPEs and UPEs with a sensitivity of 50%, a specificity of 100%, and an accuracy of 78%. At a cutoff value of 701.6 pg/mL, IL-8 differentiated CPE and UPE with a sensitivity of 80%, a specificity of 80%, and an accuracy of 86%.

CONCLUSIONS

Progressive changes in common biochemical markers (ie, pH, and protein, glucose, and LDH levels) are interrelated during stages of pleural inflammation. IL-8 may be used as an alternative marker for discriminating between CPEs and UPEs in pediatric parapneumonic effusions.

Nitric oxide level in the nasal and sinus mucosa after exposure to electromagnetic field

OBJECTIVE

The purpose of this study was to examine the changes in nitric oxide (NO) level in the nasal and paranasal sinus mucosa after exposure radiofrequency electromagnetic fields (EMF).

STUDY DESIGN AND SETTING

Thirty male Sprague-Dawley rats were randomly grouped as follows: EMF group (group I; n, 10), EMF group in which melatonin received (group II; n, 10) and the control (sham operated) group (group III; n, 10). Groups I and II were exposed to a 900 MHz. Oral melatonin was given in group II. Control rats (group III) were also placed in the tube as the exposure groups, but without exposure to EMF. At the end of 2 weeks, the rats were sacrificed, and the nasal and paranasal sinus mucosa dissected. NO was measured in nasal and paranasal mucosa.

RESULTS

The nasal and paranasal sinus mucosa NO levels of group I were significantly higher than those of the control group (group III) ( P < 0.05). However, there was no statistically significant difference between group II and the control group (group III) regarding NO output ( P > 0.05).

CONCLUSION

Exposure to EMF released by mobile phones (900 MHz) increase NO levels in the sinus and nasal mucosa.

SIGNIFICANCE

Increased NO levels may act as a defense mechanism and presumably related to tissue damage. In addition, melatonin may have beneficial effect to prevent these changes in the mucosa.

Effect of WEB 2170 BS, platelet activating factor receptor inhibitor, in the rabbit model of sinusitis

Platelet activating factor (PAF), a potent inflammatory mediator, is a biologically active phospholipid. Recent studies have shown that PAF may play an important role in the pathogenesis of inflammation. WEB 2170 BS has been shown to be a PAF antagonist both in vitro and in vivo. Nitric oxide (NO) is present in the mammalian nasal airways and originates primarily from the paranasal sinuses. Measurement of NO is thought to be a surrogate marker of upper airway inflammation. In this study, the antiinflammatory effects of WEB 2170 BS were investigated in a rabbit model of sinusitis. To induce experimental sinusitis, we applied killed Staphylococcus aureus percutaneously to the maxillary sinus of rabbits without occlusion of the natural ostium. Either WEB 2170 BS solution or placebo was administered intraperitoneally 2 hours before sinus inoculation, and this procedure was repeated twice daily for 4 days. The outcome of the treatment was determined by the measurement of NO metabolite levels and NO synthase activity in the samples of sinus mucosa and by histopathologic evaluation of sinus mucosa. The pathological grading was determined by the number of inflammatory cells found in the sinus mucosa. The levels of NO metabolites and NO synthase activity were found to be significantly lower in the WEB 2170 BS-treated group than in the control group. Histopathologic analysis of the sinus mucosa indicated decreased inflammation in the treated group as compared to the controls. These results demonstrate that WEB 2170 BS may produce significant anti-inflammatory effects in this model of sinusitis.

Expression of nitric oxide synthases in nasal mucosa from a mouse model of allergic rhinitis

Nitric oxide (NO), which is produced by nitric oxide synthase (NOS), has been recently identified as a multifunctional mediator. As for nasal tissue, however, the distribution and expression patterns of 3 isoforms of NOS, including neuronal NOS (nNOS, type I NOS), inducible NOS (iNOS, type II NOS), and endothelial NOS (eNOS, type III NOS), are still unclear. To evaluate the function of NO in the pathophysiology of nasal allergy, we investigated the distribution of NOSs in the nasal mucosa of C57BL/6 mice with allergic rhinitis to the house dust mite, Dermatophagoides farinae. Immunoreactivity to each isoform of NOS was immunohistochemically observed. In the allergic nasal mucosa, many eosinophils had infiltrated. Immunoreactivity to NOS types I and III was localized to the surface epithelial and vascular endothelial cells in both allergic and control groups without a statistically significant difference. In contrast, the type II NOS immunoreactivity was weak in normal mice and increased after allergic sensitization. The type II NOS expression of the surface epithelial and vascular endothelial cells was significantly elevated in the allergic group as compared with the control group. These findings suggest that a large amount of NO may be produced in the nasal mucosa of mice by type II NOS after allergic sensitization and that type II NOS may play an important role in the pathogenesis of allergic rhinitis.

Effects of aqueous extracts of Satureja hortensis L. on rhinosinusitis treatment in rabbit

Satureja hortensis L. (Lamiaceae) is an annual herb that used as traditional folk medicine in Eastern Anatolia region of Turkey for treatment of different infectious diseases and disorders. This study was designated to investigate anti-inflammatory effect of aqueous extract (250 mg/kg) of Satureja hortensis. Therapeutic potential of Satureja hortensis as an anti-inflammatory agent was examined by measurement of NO* metabolites and histological changes in a rabbit model of rhinosinusitis. The results showed that both activity of NOS enzyme and concentration of NO* metabolites were significantly reduced by topical administration of Satureja hortensis extract. Histological examination demonstrated no edema and/or reduced inflammation in therapy group as compared to the control. Thus, the data suggest Satureja hortensis extract may have the potential to be used as anti-inflammation agent, and can be used in the treatment of rhinosinusitis diseases.

The Effect of Topical Fluticasone on Nasal Nitric Oxide Levels in a Patient with Allergic Rhinitis

Nitric oxide (NO) in exhaled breath is produced primarily by the upper respiratory airway mucosa. The nasal output of this gas is increased in patients with allergic rhinitis. We performed a study on a 41 -year-old nonsmoking male volunteer with allergic rhinitis to investigate the effect of fluticasone nasal spray on nasal NO output (VNO). A total of 28 nasal NO measurements from both nostrils were taken during the 2-month period of June and July 2002. During the second half of the study period (treatment phase), the patient took fluticasone in doses of 100 μg per nostril once a day. During the treatment phase, nasal NO measurements were taken 10 days after the initiation of treatment. In addition, we also recorded the patient's nasal symptom scores and the grass pollen counts in the greater Pittsburgh area. The patient's mean VNO was 989.9 nl/min prior to treatment and 787.7 nl/min following treatment—a statistically significant 20.4% decrease (p<0.01) The findings of our study support the observation that topical nasal steroid treatment decreases NO production in sinonasal mucosa.

Nitric oxide (NO) and obstructive sleep apnea (OSA)

Nitric oxide (NO) and obstructive sleep apnea are inseparable. Obstructive sleep apnea could be described as the intermittent failure to transport the full complement of nasal NO to the lung with each breath. There NO matches perfusion to ventilation. NO is utilized by the efferent pathways that control the unequal, inspiratory battle between the pharyngeal dilators and the closing negative pressures induced by the thoracic musculature. Recurrent cortical arousals are a major short-term complication, and the return to sleep after each arousal uses NO. The long-term complications, namely hypertension, myocardial infarction, and stroke, might be due to the repeated temporary dearth of NO in the tissues, secondary to a lack of oxygen, one of NO's two essential substrates.

Expression of inducible nitric oxide synthase in antrochoanal polyps

OBJECTIVE

Antrochoanal polyp (ACP) is a polypoid lesion originating from the maxillary sinus, emerging from the ostium and extending to the choana. Although the etiologic causes of ACP are not known completely, it presents a fairly uniform clinical appearance. Nitric oxide (NO) has an important role in non-specific immunoreactions and inflammation in various tissues and has a main regulatory role in airway function and seems to involve in pathomechanism of several respiratory system diseases. NO is synthesized by the effect of three isoforms of nitric oxide synthase i.e. inducible NOS (iNOS). Some studies revealed that ACP has some different characteristics from the ordinary nasal polyps. In the present study, in order to compare ACP with allergic and non-allergic nasal polyps (NANP), we detected and localized the iNOS expression and also evaluate some histological parameters.

METHODS

Twenty-six cases were chosen from the files and four controls were used. The cases were separated as follows: normal inferior turbinate mucosa as control (n=4) ACPs (n=8), allergic nasal polyps (ANP) (n=9), and NANP (n=9). Five-micrometer thick sections were prepared from the paraffin sections of polyps and normal nasal mucosa to quantify the iNOS expression. iNOS protein was observed in the cytoplasm of epithelial and stromal inflammatory cells. iNOS protein expression in the groups was assessed according to the intensity of staining and histomorphological parameters, oedema, lymphocytic and eosinophilic cell infiltration were detected semi quantitatively.

RESULTS

iNOS expressions, either stromal or epithelial, were not different from each other among the four groups. Although it is not statistically significant, we noted that ANP and ACP frequently showed moderate and severe iNOS protein expression in epithelial and stromal parts when compared with NANPs and controls. Also, iNOS expression was significantly higher in the stroma of the ANPs than NANPs (P=0.012).

CONCLUSIONS

ACPs and ANPs have frequently showed moderate and significant epithelial and stromal iNOS expression. Further studies are needed in large groups to elucidate differences between ACP and the other nasal polyps.

Prevalence of endothelial nitric oxide synthase gene polymorphisms in patients with atopic asthma

BACKGROUND

Asthma is a common multifactorial disease, the aetiology of which is attributable to both environmental and genetic factors. The endothelial nitric oxide synthase (NOS3) gene has been implicated in asthma pathogenesis.

OBJECTIVE

This study investigated associations of 27 base-pair tandem repeat polymorphism in intron 4 and the Glu298Asp (G894T) variant of the NOS3 gene with atopic asthma in a Czech population.

METHODS

Polymerase chain reaction was used to determine the NOS3 genotypes in subjects with atopic asthma (n = 163) and random controls (n = 209).

RESULTS

The NOS3 allele or genotype distributions did not differ significantly between the control and asthma groups. However, the common genotype (bb) of the NOS3 polymorphism in intron 4 was found to be significantly associated with total IgE levels (P = 0.006), specific IgE levels for feathers (P = 0.0002) and a positive skin prick test for hay (P = 0.004). In one atopic patient, we identified an additional 27-bp repeat in the NOS3 gene (NOS3c), which occurred in heterozygous combination with the NOS3b allele (NOS3b/c genotype). In addition, we describe a new polymorphism (A5495G) in the NOS3 gene, which was in almost complete linkage disequilibrium with the NOS3 repeat polymorphism in intron 4. The Glu298Asp variant was not associated with asthma and/or related atopic phenotypes in our study.

CONCLUSION

Neither the NOS3 'b' allele nor the NOS3 'b/b' genotype showed any general association with atopic asthma, but they were associated with atopy-related phenotypes. We conclude that the NOS3 gene polymorphisms may act as disease modifiers in atopic asthma phenotype in our population.

A Method for off-line Nasal Nitric Oxide Measurement

We conducted a study to test the accuracy of an immediate and delayed off-line technique for measuring nasal nitric oxide (NO) by comparing it with on-line measurements. With the assistance of one volunteer, we obtained these measurements during 30 sessions over a period of 2 months. Off-line measurements were made immediately following the acquisition of NO samples and 1, 2, and 4 hours later. NO samples were obtained from nasal air collected in syringes. We found that the correlation between on-line measurements and the immediate and delayed off-line measurements ranged from 95 to 98%, according to a Bland-Altman analysis. We conclude that off-line nasal NO measurements can be reliably used in clinical practice and research projects, thus obviating the need for patients/subjects to be in close proximity to the analyzer. Off-line nasal NO measurements can effectively substitute for on-line measurements when the latter technique is not practical.