Heavy physical exercise decreases nitric oxide levels in the nasal airways in humans

A continuous production of nitric oxide (NO) takes place in human nasal airways. NO in the nasal airways is mainly derived from the paranasal sinuses. The factors that regulate NO synthesis in the upper airways are presently not known. We have investigated the effects of physical exercise on NO levels in the nasal airways. Nasal cavity NO levels were measured by chemiluminescence technique in five healthy non-smoking male subjects before, during and after 5 min of maximal exercise (245 W) on an ergometer cycle. In addition, in one subject NO levels were measured directly in the maxillary sinus during exercise. Nasal cavity NO levels were decreased by 47% after only 1 min of exercise compared with the control situation. A maximal 76% reduction was found at the end of the exercise period and thereafter NO levels slowly increased, reaching basal levels again in about 15–20 min. NO levels in the sinus decreased in a similar manner during exercise. The decrease in nasal cavity NO levels cannot be explained merely by dilution of nasal air due to changes in nasal cavity volume or increased ventilation. We conclude that the excretion of NO in the nasal airways is decreased acutely during heavy short term physical exercise.     

Nasal mucosal gene expression in patients with allergic rhinitis with and without nasal polyps

BACKGROUND: Nasal polyps are a common problem that is difficult to diagnose and treat, in part because the cause of nasal polyposis is unknown. Although information on the pathogenesis of polyposis is lacking, there are reports suggesting that a genetic predisposition underlies this disorder. OBJECTIVE: We sought to better understand the basis of nasal polyposis associated with allergic rhinitis. We hypothesize that the expression of unique genes is associated with the nasal polyposis phenotype. METHODS: We examined 12000 human genes transcribed in the nasal mucosa of patients with allergic rhinitis with and without nasal polyps. Biopsy specimens of the mucosa of patients with and without polyps were obtained after the patients refrained from the use of topical or systemic steroid therapy for 2 weeks. RESULTS: Thirty-four genes were differentially expressed between the patient groups, including those for inflammatory molecules and putative growth factors. The greatest differential expression identified by the array analysis was for a group of genes associated with neoplasia, including mammaglobin, a gene transcribed 12-fold higher in patients with polyps compared with control patients with rhinitis alone. Quantitative RT-PCR confirmed this differential expression and documented that the number of mammaglobin mRNA copies is actually 64-fold greater in tissues of patients with polyps versus control patients. The specificity of mammaglobin protein expression was evaluated by means of immunohistochemistry, which showed specific staining in nasal polyp mucosal goblet cells only in patients with polyps. CONCLUSION: These data suggest that nasal polyposis involves deregulated cell growth, using gene activation in some ways similar to a neoplasm. In addition, mammaglobin, a gene of unknown function associated with breast neoplasia, might be related to polyp growth.     

Nasal nitric oxide is increased in allergic rhinitis

Background Nitric oxide (NO) plays a major role in the regulation of vascular tone and in non-specific host defence. The epithelium in the paranasal sinuses was recently identified as the major site of NO production in the upper airways. Objective To investigate NO status in allergic rhinitis, we compared the NO concentration in the nasal cavities of control subjects (n= 19) and in patients with allergic rhinitis (n= 36) with symptoms (WS, n= 17) or without symptoms (WOS, n= 19) on the day of the test. Methods NO concentration was measured using a chemiluminescent analyser aspiring from each nasal cavity at a sampling flow rate of 0.7L/min, before and 10min after administration of a nasal vasoconstrictor. Results The mean NO concentration (± se) in the control was 235 ± 11 ppb and 225 ± 9 ppb in the right and left nostrils respectively, and was decreased by 14% and 12% by the nasal vasoconstrictor (P < 0.001). The NO concentration in patients with allergic rhinitis was significantly higher in the right and left nostrils (382 × 20 ppb and 396 ± 28 respectively, P < 0.0001 versus control). All WOS patients demonstrated normal or increased NO concentrations in both nostrils, whereas two WS patients showed decreased NO concentrations in the left nostril. Inhalation of a nasal vasoconstrictor increased NO concentration by 6% and 27% in the right and left nostrils respectively in WS patients. Conclusion Nasal NO concentration is increased in patients with allergic rhinitis. Interestingly, patients without symptoms on the day of the test also showed a clear-cut increase in nasal NO production, which could reflect a permanent inflammation of the sinus mucosa.     

Characterization of airway nitric oxide in allergic rhinitis: the effect of intranasal administration of L-NAME

BACKGROUND: Several studies have attempted to assess nasal nitric oxide (NO) levels in allergic rhinitis (AR). However, there seem to be differences in the results obtained. We therefore wanted to investigate this further by studying airway NO in AR and controls at several modalities, and also the effect of intranasal administration of the nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine-methyl ester.HCl (L-NAME). METHODS: Airway NO was determined through repeated measurements at three flow rates of air (0.5, 3, and 9 l/min), using a single-breath method and a method of nasal aspiration, in 18 patients with birch pollen AR during season and in 18 controls. RESULTS: Patients with AR were characterized by no difference in nasal but higher orally exhaled NO and a larger interindividual spread in nasal and orally exhaled NO compared to controls. We also found a greater reduction in nasal NO after L-NAME in patients compared to controls. DISCUSSION: These results indicate that several factors determine the levels of nasal NO in rhinitis. NO production in the nasal mucosa of patients with AR may be upregulated. On the other hand, this increase could be counteracted by swelling of the mucosa and secretions resulting in impaired NO diffusion from, for example, the paranasal sinuses, where particularly high levels of NO have been found. Also, the high background levels of NO from constitutive sources in the nose may blunt smaller increases in mucosal NO output. CONCLUSION: It seems that the methods for measurement of nasal NO need to be improved and standardized before we can consider to use this test in monitoring inflammation in AR.     

An open audit of montelukast, a leukotriene receptor antagonist, in nasal polyposis associated with asthma

BACKGROUND: Nasal polyposis occurs frequently in patients with intrinsic asthma, especially in those who are aspirin sensitive. It can be difficult to treat effectively, even with surgery and regular topical intranasal corticosteroids many patients are still symptomatic. OBJECTIVE: To investigate the response to montelukast, a leukotriene D4 receptor antagonist, as an add-on therapy to topical and inhaled corticosteroids in patients, both aspirin sensitive (AS) and aspirin tolerant (AT), with nasal polyposis and asthma. METHODS: Nasal polyposis symptoms were assessed by visual analogue scales; nasal polyps were assessed by nasendoscopy and via the measurement of nasal volumes by acoustic rhinometry. The nasal airway was assessed by nasal inspiratory peakflow (NIPF). Asthma was monitored using symptom scores and peak expiratory flow measurements. Aspirin sensitivity was assessed by history together with intranasal lysine aspirin challenge. Upper and lower airway nitric oxide measurements were made before and during treatment. RESULTS: Clinical subjective improvement in nasal polyposis occurred in 64% AT (P < 0.01), patients and 50% AS patients (P > 0.05); asthma improvement in 87% AT and 61% AS patients (P < 0.05 for both). Objective changes in peak flow occurred only in AT patients (P < 0.05). Acoustic rhinometry, nasal inspiratory peak flow and nitric oxide levels did not change significantly in any group, however, correlations were seen between nitric oxide levels and polyp scores and between nitric oxide levels and acoustic rhinometry changes. Improvement on montelukast therapy was not associated with any of the following variables: age, sex, skin prick test positivity, disease duration or aspirin sensitivity. (P > 0.05 for all). CONCLUSION: The findings are consistent with a subgroup of nasal polyps/asthma patients in whom leukotriene receptor antagonists are effective. This is not related to aspirin sensitivity. Further placebo-controlled studies need to be undertaken.     

Nasal nitric oxide in objective evaluation of chronic rhinosinusitis therapy

BACKGROUND: The assessment of the response of chronic rhinosinusitis (CRS) to therapy is difficult. Computerized tomographic (CT) scans cannot be repeatedly used so measures such as symptom scores, endoscopic findings, and parallel measures such as saccharin clearance time are employed instead. OBJECTIVE: To study the effect of CRS therapy on nasal nitric oxide and to see whether nasal nitric oxide level changes correlate with other assessments. METHODS: The study was a prospective randomized trial of patients with CRS, with or without polyps, who had failed initial medical therapy with douching and nasal corticosteroids and who then had abnormal CT scans. They were treated either medically or surgically, with follow up at 6 and 12 months whilst still taking nasal corticosteroids. Nasal nitric oxide was measured initially and at 6 and 12 months as well as symptom scores, endoscopy, polyp grading, and saccharin clearance time. RESULTS: Initial absolute nasal nitric oxide levels correlated inversely with CT scan changes, (P<0.001). The percentage rise in nasal nitric oxide seen on both medical and surgical treatment correlated with changes in symptom scores (P<0.001), saccharin clearance time (P<0.001), endoscopic changes (P<0.001), polyp grades (P<0.05 at 6 months, P<0.01 at 12 months) and surgical scores (P<0.01). There was no significant correlation with age, sex, smoking or allergy. CONCLUSION: Nasal nitric oxide, which is easily measured, provides a valuable non-invasive objective measure of the response of CRS to therapy. Topical nasal corticosteroids may be needed to reduce the contribution of nasal epithelial nitric oxide and allow that emanating from the sinuses to be measured.     

Nasal nitric oxide, the guardian of paranasal sinuses, is paradoxically increased by high doses of intravenous glucocorticoids

BACKGROUND: High concentrations of nitric oxide (NO) originating from a type-2 nitric oxide synthase (NOS2) located within the paranasal sinuses are measured in nasal air in man. NO is believed to play a central role in nonspecific defense of paranasal sinuses. Glucocorticoids (GCs), a therapeutic often used for a wide range of diseases, is known to strongly downregulate NOS2. AIMS OF THE STUDY: To investigate the effect of very high intravenous doses of GCs on nasal NO in man. METHODS: Nasal NO was measured in 15 patients without any history of allergy or chronic airway disorder who were treated for 3 days with a daily dose of 1000 mg methylprednisolone for an exacerbation of multiple sclerosis. Nasal NO was also measured in 30 matched control subjects. RESULTS: In control subjects, the maximal value of nasal NO [mean (SE)] was 233 (8) part per billion (ppb), and did not differ from patients with multiple sclerosis [maximum value: 219 (13) ppb; left nostril: 214 (12) ppb; right nostril: 215 (12) ppb]. After GCs treatment, nasal NO increased in patients [maximum value: 250 (13) ppb (P < 0.0001); left nostril: 249 (12) ppb (P < 0.0001); right nostril: 244 (13) ppb (P < 0.0001)]. CONCLUSIONS: We conclude that GCs do not decrease but even increase nasal NO.     

Evidence-based management of nasal polyposis by intranasal corticosteroids: from the cause to the clinic

Background: Nasal polyposis is an inflammatory disorder involving the mucosa of the nose and paranasal sinuses and affecting approximately 2-4% of the general population. Methods: A literature search of Medline and Embase was conducted to obtain an overview of the epidemiology, pathophysiology, and current treatment of nasal polyposis, focusing on evidence-based efficacy of intranasal corticosteroids (INSs) as primary and postoperative therapy. Recent research on INSs in nasal polyp treatment, along with notable historic findings, was reviewed. Results: Nasal polyps are mostly characterized by eosinophil infiltration, a complex inflammation of nasal mucosa, and possibly production of polyclonal IgE. Current treatment modalities include INSs, oral corticosteroids, and surgery; surgery is generally limited to those with an insufficient response to medical treatment. Because of their effects on eosinophil-dominated inflammation, INSs and oral corticosteroids are the primary medical treatment strategies. The very low (≤1%) systemic bioavailability of newer INSs minimizes the systemic adverse effects seen with oral corticosteroids. Conclusion:Based on randomized, controlled trials, guidelines recommend INSs as first-line therapy for nasal polyps and for care after polypectomy. Clinical data suggest INSs are effective in reducing polyp size and relieving nasal symptoms. INS treatment has also reduced nasal polyp recurrence in patients undergoing functional endoscopic sinus surgery. Treatment with these mainstay options has been found to improve quality of life, which, along with symptom improvement, is a key factor in disease treatment.     

Sinus CT scans and mediator release in nasal secretions after nasal challenge with cypress pollens

BACKGROUND: Involvement of paranasal sinuses has been suggested in allergic rhinitis but not clearly demonstrated. AIMS: To investigate the relationship between intermittent allergic rhinitis and computerized tomography (CT). METHODS: Twenty patients with intermittent rhinitis and sensitized to cypress pollens underwent unilateral nasal provocation tests (NPTs) using increasing concentrations of cypress pollens out of the pollen season. Sinus CT-scans were carried out just before a NPT and 24 h later. Nasal lavage was carried out just before a NPT, 30 min after a positive challenge and again 24 h later. Leucotriene C4/D4, intracellular adhesion molecule-1 and eosinophil cationic protein were measured in nasal secretions. RESULTS: Thirteen patients (65%) showed an alteration in their CT-scans after allergen challenge. Ten of them showed sinus changes controlateral to their allergenic provocation. Radiological changes mainly affected the osteomeatal complex and the ethmoid sinuses. Pre-existing abnormalities (13 of 20 cases) mainly concerned the maxillary sinuses. There was no correlation between CT-scan abnormalities and levels of mediators released in nasal secretions. CONCLUSIONS: We have shown that nasal allergen challenge can produce radiological changes in the paranasal sinuses. This mainly concerned the ethmoid sinuses.     

Increased expression and role of thymic stromal lymphopoietin in nasal polyposis

Purpose

Nasal polyposis is a chronic inflammatory disease of the upper airways often associated with asthma and characterized by markedly increased numbers of eosinophils, Th2 type lymphocytes, fibroblasts, goblet cells and mast cells. Previous studies have shown elevated levels of thymic stromal lymphopoietin (TSLP) in atopic diseases like asthma, atopic dermatitis and mainly in animal models of allergic rhinitis (AR). Here, we investigated the expression of TSLP in nasal polyps from atopics and non-atopics in comparison with the nasal mucosa and its potential role in nasal polyposis.

Methods

Messenger RNA expression for TSLP, thymus and activation-regulated chemokine (TARC) and macrophage derived chemokine (MDC) in nasal polyps and nasal mucosa of atopics and non-atopics was analyzed by real time PCR. Immunoreactivity for TSLP in nasal polyps and in the nasal mucosa of patients with AR and non-allergic rhinitis (NAR) was analyzed by immunohistochemistry. Eosinophil counts was analyzed by Wright-Giemsa staining and nasal polyp tissue IgE, by ELISA.

Results

Messenger RNA expression for TSLP,TARC and MDC was markedly higher in nasal polyps as compared to the allergic nasal mucosa. Immunoreactivity for TSLP was detected in epithelial cells, endothelial cells, fibroblasts and inflammatory cells of the nasal mucosa and nasal polyps. The number of TSLP+ cells was significantly greater in the nasal mucosa of AR than NAR patients. The number of TSLP+ cells in nasal polyps from atopics was significantly greater than that of non-atopics and that in the allergic nasal mucosa. The number of TSLP+ cells correlated well with the number of eosinophils and the levels of IgE in nasal polyps.

Conclusions

The high expression of TSLP in nasal polyps and its strong correlation to eosinophils and IgE suggest a potential role for TSLP in the pathogenesis of nasal polyps by regulating the Th2 type and eosinophilic inflammation.     

Nitric oxide in upper airways inflammatory diseases

In the human respiratory tract, the main production sites of exhaled nitric oxide (NO) are the nose and paranasal sinuses. In the upper airways, NO has been suggested to be involved at different levels with regulatory, protective, defensive or deleterious effects. Therefore, we review some aspects of the origin, metabolism, and functions of NO in the upper airways, together with the role of NO in some upper airways inflammatory diseases. Furthermore, we discuss the recent improvements in nasal NO measurements, which may be useful to better characterize the involvement of the NO produced by nose and paranasal sinuses in upper airways inflammatory diseases such as allergic rhinitis, nasal polyposis, sinusitis, primary ciliary dyskinesia, and cystic fibrosis. Received 9 May 2006; returned for revision 19 June 2006; accepted by M. Parnham 21 September 2006     

The effect of endogenous nitric oxide on mechanical ciliostimulation of human nasal mucosa

BACKGROUND: Endogenous nitric oxide (NO) production by the inducible NO-synthase is enhanced in the nasal respiratory epithelium of patients with allergic rhinitis. Recent experimental data suggest endogenous NO to be strongly involved in the regulation of ciliary activity, the driving force of the mucociliary transport system. OBJECTIVE: In this study, we investigated the effect of endogenous NO on mechanical stimulation of ciliary activity in a nasal mucosa explant model. METHODS: Cultures of nasal mucosa explants were incubated with TNF-alpha and bacterial lipopolysaccharides (LPS) to enhance endogenous NO production. Direct in vitro NO imaging was performed by the fluorescent NO-indicator DAF-2 DA and laser scanning confocal microscopy. Ciliary beat frequency (CBF) was determined using a photoelectric technique. Mechanical stimulation was performed by two consecutive flow increments in a closed perfusion chamber. Endogenous NO-synthesis was blocked by l-NAME before the second flow stimulation. RESULTS: Under control conditions the mean rise of CBF relative to baseline was 30.2% during the first flow increment and 30.7% during the second flow increment. Blocking of the endogenous NO synthesis in TNF-alpha/LPS-stimulated cultures reduced baseline CBF by 10.6+/-2.1% (P<0.05) but the effect of mechanical ciliostimulation on CBF remained unchanged (36.0% vs. 38.2%). CONCLUSION: In conclusion, endogenous NO- and Ca(2+)-dependent mechanical stimulation of ciliary activity probably use independent intracellular signalling pathways. The combination of both effects on ciliary activity is likely to improve the local defence against inhaled allergens in patients with nasal allergies.     

United airways again: high prevalence of rhinosinusitis and nasal polyps in bronchiectasis

Background: Although various relationships between the lower and upper airways have been found, the association of bronchiectasis with chronic rhinosinusitis and nasal polyps has not been thoroughly evaluated. This study was undertaken to examine the association of idiopathic and postinfective bronchiectasis with chronic rhinosinusitis and nasal polyposis. Methods: In a prospective study, 56 patients with idiopathic and 32 with postinfective bronchiectasis were evaluated for chronic rhinosinusitis and nasal polyposis by using EP³OS criteria and assessing: symptoms score, nasal endoscopy, sinonasal and chest CT scan, nasal and lung function and nasal and exhaled NO. Results: Most bronchiectasis patients (77%) satisfied the EP³OS criteria for chronic rhinosinusitis, with anterior (98.5%) and posterior (91%) rhinorrhea and nasal congestion (90%) being the major symptoms. Patients presented maxillary, ethmoidal and ostiomeatal complex occupancy with a total CT score of 8.4 ± 0.4 (0–24). Using endoscopy, nasal polyps with a moderate score of 1.6 ± 0.1 (0–3) were found in 25% of patients. Nasal NO was significantly lower in patients with nasal polyposis (347 ± 62 ppb) than in those without them (683 ± 76 ppb; P < 0.001), and inversely correlated (R = ?0.36; P < 0.01) with the ostiomeatal complex occupancy. In the chest CT scan, patients with chronic rhinosinusitis showed a higher bronchiectasis severity score (7.2 ± 0.5; P < 0.001) than patients without (3.7 ± 0.7). The prevalence of chronic rhinosinusitis, nasal polyps and other outcomes were similar in idiopathic and postinfective bronchiectasis. Conclusions: The frequent association of chronic rhinosinusitis and nasal polyposis with idiopathic and postinfective BQ supports the united airways concept, and it suggests that the two type of bronchiectasis share common etiopathogenic mechanisms.     

Effect of natural seasonal pollen exposure and repeated nasal allergen provocations on elevation of exhaled nitric oxide

Background:  Exhaled nitric oxide (FENO) is a marker for allergic airway inflammation. We wondered whether in patients with intermittent allergic rhinitis only (i) natural pollen exposure and (ii) artificial pollen exposure by repeated nasal allergen provocations may lead to an elevation of FENO.
Methods:  In two prospective studies, we compared the FENO of nonatopic controls with the FENO of nonasthmatic individuals with mild intermittent rhinitis to tree and/or grass pollen. Study I: 13 atopic individuals and seven controls had measurements of FENO, blood eosinophils and eosinophilic cationic protein (ECP) before, during and after pollen season. Study II: 16 atopic individuals and 12 controls had nasal allergen provocations on four following days out of pollen season, with daily measurements of FENO before, 2 and 6 h after provocation, and determination of blood eosinophils, ECP and FEV1 at baseline, on days 5 and 10–12.
Results:  Natural pollen exposure (study I) caused a significant elevation of FENO in allergic individuals. Nasal allergen provocations (study II) did not elicit a statistically significant rise neither of FENO nor of blood eosinophils between baseline and day 5. However, a subgroup of four individuals with a rise of blood eosinophils during nasal allergen provocations showed also a rise of FENO.
Conclusions:  We suppose that in allergic rhinitis a concomitant reaction of the bronchial system is dependent on a strong local inflammation leading to a generalized immune stimulation.     

Nitric oxide evaluation in upper and lower respiratory tracts in nasal polyposis

Background A decrease in nasal nitric oxide (NO) and an increase in exhaled NO have been demonstrated in patients with nasal polyposis (NP).
Objectives The aims were to evaluate the flux of NO from the three compartments of the respiratory tract, namely, upper nasal, lower conducting and distal airways, and to search for relationships between NO parameters and indexes of upper and lower disease activity (bronchial reactivity and obstruction). The effect of medical treatment of polyposis was also evaluated.
Methods Seventy patients with polyposis were recruited. At baseline, pulmonary function tests (spirometry, plethysmography, bronchomotor response to deep inspiration using forced oscillation measurement of resistance of respiratory system, methacholine challenge, multiple flow rates of exhaled NO and nasal NO measurements) were performed together with an assessment of polyposis [clinical, endoscopic and computed tomography (CT) scores].
Results Statistical relationships were demonstrated between nasal NO flux and severity scores (clinical: ρ=−0.31, P =0.015; endoscopic: ρ=−0.57, P <0.0001; CT: ρ=−0.46, P =0.0005), and between alveolar NO concentration and distal airflow limitation (FEF_25–75, ρ=−0.32, P =0.011). Thirty-six patients were assessed after 11 [7–13] (median [interquartile]) months of medical treatment, demonstrating an improvement in clinical and endoscopic scores, an increase in nasal NO flux, a decrease in NO flux from conducting airways, an improvement in the mild airflow limitation (forced expiratory volume in 1 s, FEF_25–75, even in non-asthmatic patients) and a decrease in the bronchoconstrictor effect of deep inspiration.
Conclusions The medical treatment of NP improves both airway reactivity and obstruction, whatever the presence of asthma, suggesting a functional link between upper and lower airway functions.     

In vitro diagnosis of chronic nasal inflammation

BACKGROUND: Differential diagnosis of chronic nasal inflammation is insufficient when based solely on clinical examination and radiography of paranasal sinuses. Patients complain about more or less similar symptoms. Activation of mast cells and eosinophils is pivotal in nasal inflammation. OBJECTIVE: To compare tryptase and eosinophilic cationic protein (ECP) in nasal secretions in different forms of chronic nasal inflammation and to establish norm values. METHODS: The study included 1710 patients presenting with nasal complaints. Nasal secretions were gained by the cotton wool method and analysed for tryptase, as a marker of mast cell activation, and for ECP, as a marker of tissue eosinophilia and activation. Patients were grouped according to their diagnosis: chronic, non-allergic rhinosinusitis (sinusitis, n=194), non-allergic nasal polyposis (polyposis, n=138), non-allergic rhinitis with eosinophilia syndrome (NARES, n=198), isolated perennial allergic rhinitis (AR) (n=126), isolated seasonal AR (n=132), and patients allergic to both, seasonal and perennial allergens (n=193). Seven hundred and twenty-nine patients with nasal complaints due to a deviated septum and without any nasal inflammation served as controls. RESULTS: Nasal tryptase was highly significantly (P<0.001) elevated in polyposis, NARES, and in AR. ECP was highly significantly (P<0.001) elevated in all groups of patients suffering from chronic nasal inflammation. Based on our data and method we established norm values (95% confidence interval of mean value) for nasal tryptase in healthy adults, ranging from 12.0 to 18.7 ng/mL and for ECP ranging from 84.4 to 102.6 ng/mL. CONCLUSION: Mast cells and eosinophils are involved in non-allergic and allergic forms of chronic nasal inflammation. We established an in vitro assay for tryptase and ECP in nasal secretions and defined norm values based on our data and method. In vitro measurement of biological markers in nasal secretions provides important information for differential diagnosis and therapeutic strategies of chronic nasal inflammation.     

The increased number of epithelial mast cells in nasal polyps and adjacent turbinates is not allergy-dependent

Respiratory epithelial mast cells are an expression of airway inflammatory processes. Nasal epithelial mast cells are known to be increased in allergic rhinitis and have now been examined in patients with nasal polyps. Metachromatic cell counts (mean +/- standard error) expressed as the sum of large mast cells, atypical mast cells and basophils in epithelial scrapings of the inferior turbinates, assessed after Carnoy's fixation and toluidine blue staining (pH 0.5), were 37.5 +/- 29 in non-allergic normal control subjects (n = 11), 435 +/- 130 in polyp patients who were allergic (n = 18), and 699 +/- 267 in polyp patients who were not allergic (n = 8). Metachromatic cell counts in epithelial scrapings obtained in vivo from nasal polyps of allergic patients (n = 8) were 1769 +/- 962, and 2308 +/- 1544 from polyps of non-allergic patients (n = 5); metachromatic counts were 2089 +/- 633 in epithelial scrapings from excised polyps of allergic patients (n = 14) and 2214 +/- 640 from polyps of non-allergic patients (n = 13). It is concluded that the number of metachromatic cells in the epithelium of nasal polyps and the adjacent nasal mucosa is elevated compared with normal nasal epithelium and the increased number does not depend upon allergy.     

Nasal nitric oxide and nasal allergy

Measurements of nasal nitric oxide (nNO) are attractive because they are completely noninvasive and can easily be performed. The measurements may be useful in the early diagnosis of patients with chronic airway disorders such as Kartager's syndrome and cystic fibrosis. The possible use of nNO measurements in the diagnosis and treatment of allergic rhinitis still needs to be further evaluated because of the variable and also contradicting findings of nNO concentrations in this disease. In this review we will discuss the origin, production and measurement of nNO as well as the effect of allergic rhinitis, nasal allergen challenge and medication on nNO. Subsequently, we examine published data on allergic rhinitis and nNO, and summarize the effect of treatment of rhinitis on nNO. Finally, we discuss the potential future role for nNO in the diagnosis and management of allergic rhinitis.