Airway inflammation in severe asthma is not well characterized but may involve neutrophils. We have compared induced sputum profiles in patients with asthma of varying severity and normal control subjects. We have also measured exhaled nitric oxide (NO) as a noninvasive marker of inflammation. Asthma severity was based on clinical features before treatment and the minimum medication required to maintain asthma control at the time of sputum induction, and classified as (1) mild: treated with inhaled beta(2)-agonist occasionally (n = 23; FEV(1), 91%; peak expiratory flow (PEF) variability, 10.5%), (2) moderate: requiring medium dose inhaled steroids to maintain control (n = 16; FEV(1), 88%; PEF variability, 9.1%), and (3) severe: despite using inhaled and oral steroids (n = 16; FEV(1), 61%; PEF variability, 36.2%). The asthmatic patients were nonsmokers with evidence of airway hyperresponsiveness or reversible airway obstruction, and free of respiratory tract infection for at least 6 wk. Sputum revealed significantly increased neutrophil numbers in severe asthma (53.0 [38.4- 73.5]%, p < 0.05) compared with mild asthma (35.4 [29.8-46.1]%) and normal control subjects (27.7 [20.6-42.2]%). Interleukin-8 (IL-8) and neutrophil myeloperoxidase (MPO) levels were increased in asthmatic patients, with the highest levels in severe asthma. Eosinophil numbers were increased in both mild and severe asthma, but interleukin-5 (IL-5) levels were highest in mild asthma, whereas eosinophil cationic protein (ECP) levels were highest in severe asthma. Exhaled NO levels were highest in asthmatic untreated with corticosteroids, but there was no significant difference between asthmatics using corticosteroids (Groups 2 and 3), regardless of clinical asthma severity. This confirms the role of eosinophils in asthma but suggests a potential role of neutrophils in more severe asthma.

steroids 4 and the levels are not modulated by bronchodilator therapy. 5 However, in asthmatic Background -Eosinophils in induced sputum and exhaled nitric oxide (NO) are subjects receiving inhaled corticosteroids the levels are reduced. 6 This suggests that exhaled currently used as non-invasive markers in the assessment of airway inflammation in NO may be used as a surrogate marker of airway inflammation. asthma. As both sputum eosinophils (%) and exhaled NO are raised in asthmaticThe number of sputum eosinophils and the amount of eosinophil cationic protein (ECP) subjects not receiving inhaled steroids and decreased following corticosteroid in induced sputum is associated with asthma severity. There are correlations between sputherapy, a relationship between them is plausible.tum eosinophils and sputum ECP levels with FEV 1 . 7-9 Also, sputum obtained from asthMethods -Exhaled NO was measured by chemiluminescence analyser, sputum in-matics under exacerbation contain very high numbers of eosinophils 7 10 11 but they are reduction by 3.5% saline inhalation, and bronchial responsiveness was measured as duced following corticosteroid treatment. 13This evidence justifies the validity of using PC 20 FEV 1 methacholine in 35 stable asthmatic patients using 2 agonist alone and sputum eosinophil number or sputum levels of ECP to monitor asthma severity. the correlation between these non-invasive markers of airway inflammation was Bronchial hyperresponsiveness (BHR), an exaggerated bronchoconstrictor response to instudied. Results -There were significant cor-haled stimuli, is a key feature of asthma and may be used as an indicator of asthma severity. relations between exhaled NO and PC 20 (r=−0.64), exhaled NO and sputum eos-BHR relates closely to the severity of asthma, the frequency of symptoms, and the need for inophils (%) (r=0.48), and also between sputum eosinophils (%) and PC 20 (r= treatment.14 The aim of our study was to examine the −0.40). Conclusion -The correlation between ex-relationship between exhaled NO and other non-invasive markers of inflammation, inhaled NO and PC 20 suggests that exhaled NO or the mechanisms leading to its in-cluding the number of eosinophils, the amount of ECP in induced sputum, and BHR, and also crease may contribute to airway hyperresponsiveness in asthma. Furthermore, its relationship with % predicted FEV 1 . Such a correlation would allow us to evaluate the the relationship between sputum eosinophils (%), exhaled NO, and PC 20 high-clinical utility of exhaled NO and its potential as a surrogate marker of airway inflammation light the potential use of eosinophils (%) in induced sputum and exhaled NO to in asthma. monitor the severity of asthma. (Thorax 1998;53:91-95)

We show here that upconversion phosphors can be imaged both by infrared excitation and in a scanning electron microscope. We have synthesized and characterized for this work up-converting phosphor nanoparticles nonaggregated nanocrystals of size range 50-200 nm. We have investigated the optical properties of 50-200 nm nanoparticles and found a square dependence of the emitted visible fluorescence on the infrared excitation and verified that under electron excitation similar narrow band emission spectra can be obtained as is seen with IR upconversion. The viability of the nanoparticles for biological imaging was confirmed by imaging the digestive system of the nematode worm Caenorhabditis elegans, and we have confirmed using energy-dispersive X-ray analysis that the up-conversion nanoparticles can be identified in a scanning electron microscope at high spatial resolution.

Peroxynitrite is a potent oxidant formed by the rapid reaction of the free radicals nitric oxide (NO) and superoxide. It causes airway hyperresponsiveness and airway epithelial damage, enhances inflammatory cell recruitment, and inhibits pulmonary surfactant. Asthma is characterized by increased airway hyperresponsiveness, airway epithelial shedding, and inflammation. We examined the production of peroxynitrite and the expression of inducible nitric oxide synthase (iNOS) in airways of asthmatic patients compared to normal control subjects. We also performed a double-blind, crossover randomized-order, placebo-controlled study on 10 asthmatic patients to study the effects of inhaled glucocorticoid treatment (Budesonide) on the formation of peroxynitrite and NO. Fiberoptic bronchial biopsies were examined by immunohistochemistry with antiserum to nitrotyrosine, a marker of protein nitration by peroxynitrite. We also examined the expression of iNOS by immunohistochemistry and in situ hybridization, and measured exhaled NO by chemiluminescence. We correlated the airway production of peroxynitrite with pulmonary functions and airway responsiveness. In airway passages of control subjects, there was weak or no nitrotyrosine immunoreactivity. In contrast, there was strong immunoreactivity for nitrotyrosine in the airway epithelium and inflammatory cells in the airways of persons with asthma. Budesonide treatment resulted in a significant reduction in nitrotyrosine immunoreactivity. Expression of iNOS was evident in the airway pithelium of controls and asthmatic patients, but was significantly more abundant in asthmatic patients. The presence of nitrotyrosine in the airway epithelium (r=-0.841, P<0.0001; r=-0.771, P=0.0004) and inflammatory cells (r=-0.727, P=0014; r=-0.681, P=0.004) correlated inversely with methacholine PC20 and forced expiratory volume in 1 s, respectively. Asthma is associated with increased peroxynitrite formation in the airways, which is reduced after Budesonide treatment. The potent oxidant peroxynitrite may contribute to airway obstruction and hyperresponsiveness and epithelial damage in asthma.