Hiroshi Iwamoto

Hiroshima University, Hirosima, Hiroshima, Japan

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Publications (12)36.4 Total impact

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    ABSTRACT: Background and objectiveAirway resistance and reactance measured by forced oscillometry have been used to measure the severity of airway obstruction in chronic obstructive pulmonary disease (COPD) patients. The aims of this study were to assess the effects of tachypnoea on airway resistance and reactance and to correlate these with the severity of dyspnoea. We also evaluated the effects of short-acting β2-agonist (SABA) on these measurements.Methods Airway resistance and reactance were measured with an impulse oscillation system (IOS) in 20 COPD and 10 control participants during resting respiration and metronome-paced breathing at 20, 30 and 40 tidal breaths/min. The same measurements were made for COPD patients after SABA inhalation. Dyspnoea was evaluated using the modified Medical Research Council (MRC) scale.ResultsIn patients with COPD, higher respiratory rates increased expiratory and inspiratory resistance at 5 Hz (R5), the difference in respiratory resistance at 5 Hz and 20 Hz (R5–R20), resonant frequency and decreased expiratory reactance. The decreases in expiratory reactance from 20 to 40 tidal breaths/min were significantly correlated with MRC scores. SABA inhalation significantly reduced the effect of increased respiratory rate on the reactance measurements.Conclusions Characteristic changes in IOS measurements, particularly expiratory reactance, induced by increased respiratory rates, were correlated with severity of dyspnoea in COPD patients during their daily lives. IOS and paced breathing may be useful for assessing breathlessness in COPD.
    Respirology 10/2014; · 2.78 Impact Factor
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    ABSTRACT: BACKGROUND: Forced oscillometry is a non-invasive method to measure respiratory resistance and reactance. In this study, we investigated the characteristics of measurements obtained with an impulse oscillation system (IOS) for patients with interstitial lung disease (ILD). METHOD: IOS and spirometry were performed in 64 ILD patients, 54 asthma patients, 49 chronic obstructive pulmonary disease (COPD) patients, and 29 controls. Respiratory resistance and reactance were assessed as measurements averaged over several tidal breaths (whole-breath analysis) and as measurements separately averaged during inspiration and expiration (inspiratory-expiratory analysis). RESULTS: Whole-breath IOS analyses for ILD patients showed increased resistance at 5 Hz and decreased reactance at 5 Hz (X5) compared with controls, although these features were also found in asthma and COPD patients. Inspiratory-expiratory analysis demonstrated that the changes in X5 and reactance area (AX) between inspiration and expiration (ΔX5 and ΔAX, respectively) were significantly different from those in asthma patients, COPD patients, and controls. However, multiple linear regression analysis showed that the presence of ILD was independently associated with ΔX5, but not with ΔAX. Furthermore, ΔX5 was inversely correlated with vital capacity and diffusing capacity of carbon monoxide in ILD patients. CONCLUSIONS: Our results suggest that ΔX5 is a characteristic feature of IOS measurements in ILD patients, which is clearly different from those in asthma and COPD patients. This within-breath X5 change in ILD might be associated with its severity and physiological abnormality, although further studies are needed to investigate its cause.
    Respiratory medicine 04/2013; · 2.33 Impact Factor
  • Nihon Naika Gakkai Zasshi 05/2012; 101(5):1401-3.
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    ABSTRACT: Recent studies suggest that plasminogen activator inhibitor-1 (PAI-1), a major inhibitor of the fibrinolytic system, may promote the development of asthma. To further investigate the significance of PAI-1 in the pathogenesis of asthma and determine the possibility that PAI-1 could be a therapeutic target for asthma, this study was conducted. First, PAI-1 levels in induced sputum (IS) from asthmatic subjects and healthy controls were measured. In asthmatic subjects, IS PAI-1 levels were elevated, compared with that of healthy controls, and were significantly higher in patients with long-duration asthma compared with short-duration asthma. PAI-1 levels were also found to correlate with IS transforming growth factor-β levels. Then, acute and chronic asthma models induced by ovalbumin were established in PAI-1-deficient mice and wild-type mice that received intra-airway administrations of small interfering RNA against PAI-1 (PAI-1-siRNA). We could demonstrate that eosinophilic airway inflammation and airway hyperresponsiveness were reduced in an acute asthma model, and airway remodeling was suppressed in a chronic asthma model in both PAI-1-deficient mice and wild-type mice that received intra-airway administration of PAI-1-siRNA. These results indicate that PAI-1 is strongly involved in the pathogenesis of asthma, and intra-airway administration of PAI-1-siRNA may be able to become a new therapeutic approach for asthma.
    AJP Lung Cellular and Molecular Physiology 09/2011; 301(6):L908-16. · 3.52 Impact Factor
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    ABSTRACT: Bisphosphonates are widely used for the treatment of metastatic skeletal tumors and hypercalcemia resulting from malignant tumors. Zoledronic acid (ZOL), a third-generation bisphosphonate agent, was recently demonstrated to show synergistic antitumor activity of ZOL when combined with chemotherapy in lung cancer patients. However, whether ZOL exerts direct antitumor activity on lung cancer remains unclear. Here, we report an atypical case encountered while treating a 57-year-old woman with pulmonary adenocarcinoma and multiple metastases of the liver, left adrenal gland, and bone. The nonskeletal lesions, consisting of the primary lesion and hepatic metastasis, regressed after treatment with ZOL alone. We believe this case demonstrates a possible antitumor effect of ZOL against lung cancer.
    Hiroshima journal of medical sciences 03/2011; 60(1):7-9.
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    ABSTRACT: S-1 is a novel oral fluorouracil prodrug that plays a role in non-small cell lung cancer (NSCLC). Docetaxel (DTX) is one of the standard agents for relapsed NSCLC. We performed a phase I study of DTX plus S-1 combination therapy as second-line treatment for NSCLC to determine the maximum tolerated dose (MTD) and recommended dose (RD). Patients with recurrent NSCLC, aged 20-74 years with an Eastern Cooperative Oncology Group performance status of 0-1 and measurable lesions, were enrolled. The treatment consisted of four dose levels. The patients received DTX (40-60 mg/m(2) intravenously on day 1) and S-1 (65-80 mg/m(2) orally, daily on days 1-14) for each 21-day cycle. Three to six patients were treated at each dose level with the two drugs, with MTD defined as the dose level at which dose-limiting toxicity (DLT) occurred in 33% of the patients. A total of 17 patients were enrolled. At dose level 4 (DTX, 60 mg/m(2); S-1, 80 mg/m(2)) 3 of 5 patients experienced DLT and this level was regarded as the MTD. Therefore, dose level 3 (DTX, 60 mg/m(2); S-1, 65 mg/m(2)) was selected as the RD for subsequent studies. The DLTs were neutropenia (grade 4) and mucositis (grade 3). The response rate was 5.9% (1 of 17 patients achieved a partial response) and 14 of 17 patients achieved stable disease. This combination regimen showed a tolerable and manageable profile in recurrent NSCLC and therefore warrants further evaluation.
    Oncology letters 01/2011; 2(1):167-170. · 0.24 Impact Factor
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    ABSTRACT: We have treated patients with non-small-cell lung cancer (NSCLC) who developed leptomeningeal metastases (LM) during gefitinib therapy, and then found symptomatic improvement following treatment change to erlotinib. Based on this experience, we wondered whether erlotinib could be detected in cerebrospinal fluid (CSF) when it was used for NSCLC patients with LM. This study was conducted to determine erlotinib concentrations in CSF and assess responses to erlotinib in patients with NSCLC developing LM during gefitinib therapy. Three advanced NSCLC patients with LM that developed during gefitinib therapy were treated with erlotinib. On day 28 after the initiation of erlotinib treatment, plasma and CSF were obtained and the concentrations of erlotinib in these samples were measured. Eastern Cooperative Oncology Group (ECOG) performance status (PS) and neurologic symptoms were determined. Erlotinib CSF penetration was 6.3% ± 6.1% (mean ± SD). In cases 1 and 2, we observed improvements in ECOG PS and neurologic symptoms. In case 3, cytological improvement was seen in the CSF. In each patient, deletion of exon 19 or exon 21 L858R mutation of the epidermal growth factor receptor (EGFR) gene was detected in carcinoma cells from the CSF. We report on 3 patients with NSCLC who had developed LM during gefitinib treatment and showed clinical improvements following change to erlotinib therapy. In all cases, small but measurable penetration of erlotinib into CSF was observed. Because EGFR mutations were detected in all cases, we suggest that erlotinib is a therapeutic option for LM carcinoma cells with EGFR mutations.
    Cancer Chemotherapy and Pharmacology 01/2011; 67(6):1465-9. · 2.80 Impact Factor
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    ABSTRACT: A 70-year-old woman with breast cancer treated with hormonal therapy had progressive shortness of breath for one month. Chest radiograph and computed tomography showed mild interstitial changes, but could not account for her respiratory failure. Lymphangitic carcinomatosis, drug-induced pneumonitis, idiopathic interstitial pneumonitis, opportunistic infection, and pulmonary edema were considered in the differential diagnosis of the CT findings. A perfusion scan revealed numerous small subsegmental perfusion defects in both lung fields. Bronchoalveolar lavage fluid (BALF) contained some cancer cells, suggesting lymphangitic carcinomatosis. Transbronchial biopsy (TBLB) specimen showed tumor emboli in small pulmonary arteries. Immunohistochemical findings of TBLB specimen were consistent with breast cancer cells. A diagnosis of tumor microembolism caused by breast cancer metastasis was made. Antemortem diagnosis of tumor microembolism is very difficult. Here, we report a case of tumor microembolism diagnosed by perfusion scan and TBLB.
    Nihon Kokyūki Gakkai zasshi = the journal of the Japanese Respiratory Society. 08/2009; 47(8):687-91.
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    ABSTRACT: We previously reported a mouse model of bronchial asthma showing eosinophilic inflammation, but not airway hyperresponsiveness (AHR), after prolonged antigen exposure. This model showed an increase of IL-12 in the lung. The aim of this study was to investigate the role of IL-12p40 in a murine asthma model with prolonged antigen exposures. An ovalbumin (OVA)-induced asthma model was first established in wild-type (WT) and IL-12p40-deficient (IL-12p40(-/-)) mice. Both strains of mice were further exposed to either OVA (prolonged exposure group) or phosphate-buffered saline (positive control group) 3 days per week for 3 weeks. During week 4, both groups of mice were given a final challenge with OVA. Prolonged antigen exposures resulted in marked suppression of airway eosinophilia in both WT and IL-12p40(-/-) mice. However, AHR persisted in IL-12p40(-/-) but not in WT mice. There were no significant differences of IL-5, IL-13 or IFN-gamma levels in bronchoalveolar lavage fluid between WT and IL-12p40(-/-) mice. The hydroxyproline content of the lung and peribronchial fibrosis were, however, significantly increased in IL-12p40(-/-) mice. The results suggest that endogenous IL-12p40 is essential for inhibition of AHR and peribronchial fibrosis, but not eosinophilic inflammation, in a murine asthma model with prolonged antigen exposures.
    Clinical & Experimental Allergy 12/2008; 39(2):290-8. · 4.79 Impact Factor
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    ABSTRACT: The airway inflammation of chronic obstructive pulmonary disease (COPD) demonstrates a poor response to the anti-inflammatory actions of corticosteroids. However, long-acting beta(2)-agonists and low-dose theophylline are reported to have a possible anti-inflammatory effect in COPD. The aim of this study was to compare the effects of treatment between theophylline and the tulobuterol patch (transdermal patch preparation designed to yield sustained beta(2)-agonistic effects for 24h) on airway inflammation in addition to quality of life (QOL) and pulmonary function in mild-to-moderate COPD. The study subjects consisted of 26 patients with COPD who were treated with theophylline or tulobuterol for 8 weeks with a wash-out period of 4 weeks in a randomized open-label crossover study. We prospectively investigated the differential cell counts and levels of inflammatory markers in induced sputum before and after treatment with theophylline and tulobuterol. We also examined pulmonary function and quality of life (QOL) as assessed by St. George's Respiratory Questionnaire. In the induced sputum, the total inflammatory cell count and number of neutrophils were significantly reduced by treatment with low-dose theophylline. Neither of these parameters was significantly changed by treatment with tulobuterol. Pulmonary function measurements such as FEV(1), FEV(1) % pred, FVC, PEF, MEF(50), and MEF(25) were significantly improved by the treatment with low-dose theophylline but not tulobuterol. The total QOL scores, levels of interleukin 8 and myeloperoxidase in the supernatants of induced sputum, and serum levels of hypersensitive C-reactive protein were not significantly changed by either of the treatments. These results suggest that treatment with low-dose theophylline but not the tulobuterol patch may have anti-inflammatory effects and improve pulmonary function in mild-to-moderate COPD.
    Pulmonary Pharmacology &amp Therapeutics 11/2008; 21(6):874-8. · 2.54 Impact Factor
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    ABSTRACT: Chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality from cardiovascular disease. Although a close association between COPD and atherosclerosis has been speculated, such scientific information is limited. To evaluate subclinical atherosclerosis in smokers with airflow limitation. The subjects of this study were healthy middle-aged men. Smokers with airflow limitation (n = 61) and age-matched control smokers (n = 122) and control never-smokers (n = 122) without airflow limitation were included in the present study. Subjects with diabetes, acute infection, and respiratory disease other than COPD were excluded beforehand. All subjects underwent chest radiogram, spirometry, blood sampling, and carotid ultrasonography. We determined carotid intima-media thickness and focal atheromatous plaque as indicators of subclinical atherosclerosis. Mean carotid intima-media thickness was greater in smokers with airflow limitation than in control smokers (P < 0.01) and control never-smokers (P < 0.005). Focal carotid plaque was significantly more prevalent in smokers with airflow limitation than in control never-smokers (P < 0.005). Multivariate analyses showed significant associations between thickened intima-media thickness and decreased percent predicted FEV(1) (P = 0.001) and between plaque and log(10) C-reactive protein (P = 0.013) independent of age, pack-years of smoking, body mass index, peripheral mean arterial pressure, heart rate, glucose, and low-density lipoprotein cholesterol. Smokers with airflow limitation had exaggerated subclinical atherosclerosis. This study suggests that middle-aged men who are susceptible to COPD may also be susceptible to vascular atherosclerosis by smoking, and atherosclerotic change starts early in the disease process of COPD.
    American Journal of Respiratory and Critical Care Medicine 10/2008; 179(1):35-40. · 11.04 Impact Factor
  • European Respiratory Journal 07/2008; 31(6):1379-80. · 6.36 Impact Factor