Japanese Journal of Allergology

Objective: Recently many of the inhaled drugs are provided as dry powder formula and prescribed for such diseases as COPD and asthma exacerbation. Inspiratory flow rate through the dry powder device (DPI) has a significant influence on therapeutic response in these disease conditions. We planned to measure flow vs. pressure relationships of almost all of the DPIs available in Japan. Methods: Driving pressure (P_I) and flow through the DPI were measured and the linear regression lines between P_I and flow^2 were drawn. Results: The slope and intercept of the regression lines were as follows: Turbuhaler for Pulmicort 79.26(l/s)^2/cmH_2O, 626(l/s)^2, Turbuhaler for Symbicort 88.99, 688, Twisthaler 56.37, 478, Diskus 125.98, 872, Diskhaler, 166.98, 780, Handihaler, 54.88, 498, Clickhaler, 78.37, 452. We drew P_I vs flow curves of each DPIs for instruction of DPI devices to the patients. Conclusion: Inspiratory pressure is an excellent parameter to indicate optimal flow through DPI. Early escalation of medication may be important in the patients using Turbuhaler or Twisthaler that has higher resistance in inspiratory channel.

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Background: The fraction of exhaled nitric oxide (FeNO) is a useful marker of asthma control. The FeNO measurement with two offline methods and NIOXmino may be more affordable, no studies have examined the differences in FeNO values measured with various methods in adult asthmatics. Methods: The study population comprised 39 stable asthmatics treated with inhaled steroids at our outpatient clinic. FeNO values were measured by two offline methods (Sievers and CEIS), NIOXmino. Results: FeNO_<NIOXmino> values were significantly correlated with those of FeNO_<Sievers> (r=0.935, p<0.001) and FeNO_<CEIS> (r=0.908, p<0.001). However, FeNO_<NIOXmino>, values were low compared with FeNO_<Sievers> (FeNO_<NIOXmino>=0.848×FeNO_<Sievers>) and FeNO_<CEIS> (FeNO_<NIOXmino>=0.672×FeNO_<CEIS>). Conclusion: Differences exist in the values of FeNO measured by various methods: conversion equations are needed to compare the FeNO values among these three methods.

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Background: Therapeutic effect of omalizumab was studied in Japanese patients with severe asthma. Methods: Omalizumab was administered to 10 patients with bronchial asthma diagnosed as severe or very severe persistent asthma according to Asthma Prevention Management Guideline 2009, Japan (JGL 2009). Therapeutic efficacy was assessed 16 weeks after starting the treatment using Asthma Control Test (ACT), pulmonary function tests, and the peripheral eosinophil counts. In addition, number of acute exacerbation in 16-week period after starting the treatment was compared with that in 16-week period before the treatment and the previous year respectively. The questionnaire whether or not to continue omalizumab was conducted 16 weeks after starting the treatment. Results: The total ACT score rose from 14.8 to 19.1 and peripheral eosinophil count decreased from 355.2/μl to 209.8/μl after starting the treatment. Peak expiratory flow and forced expiratory volume in one second also increased, though differences were insignificant. Number of acute exacerbation decreased from 3.0 times before the treatment and 2.4 times the same time last year to 1.3 times after starting the treatment. The result of the questionnaire revealed that patients wanted to discontinue because of financial burden, ambulant burden, and side effect, but no one responded to be ineffective. In fact, only the one discontinued omalizumab. Conclusion: Omalizumab produced improvement in subject symptoms and reduced acute exacerbation in patients with severe or very severe persistent asthma. The future challenge is to reduce financial and ambulant burden on patients.

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Background: Increased osmolality of the airway surface fluid due to water loss associated with hyperventilation is considered to be a cause of exercise-induced asthma (EIA). Aim: We investigated the influence of changes in osmolality on airway epithelial ion transport in guinea pigs. Methods: We explored from measuring open circuit potential difference in challenge with hypertonic saline or mannitol. Results: Diphenylamine-2-carboxylate (DPC), amiloride, and disodium cromoglycate (DSCG) prevented an increase of the potential difference (PD) after exposure of tracheal mucosa to 0.9-10.8% hypertonic saline solutions (HSSs) (p<0.05, p<0.01, and p<0.01, respectively on 1.8%). An increase of the PD was observed after a single dose of 1.8% hypertonic saline solution (HSS) was applied to the mucosa, but no increase was observed after a single exposure to a 585mOsm/kg aqueous mannitol solution (585AMS). The results remained the same when a Cl-free solution was used as the perfusate. The change of airway epithelial cell thickness was only suppressed significantly by DPC (p<0.01) after 1.8% HSS challenge. Conclusions: Not only the change of osmolality, but also changes of the Cl^- and Na^+ concentrations in airway surface fluid seem to have an important influence on the PD. cAMP-dependent Cl^- channel may have a role, and the same mechanism may provoke EIA.

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