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Featured researches published by Ryota Okazaki.


Allergology International | 2011

Correlation between Asian dust storms and worsening asthma in Western Japan.

Masanari Watanabe; Akira Yamasaki; Naoto Burioka; Jun Kurai; Kazuhiko Yoneda; Atsushi Yoshida; Tadashi Igishi; Yasushi Fukuoka; Masaki Nakamoto; Hiromi Takeuchi; Hisashi Suyama; Toshiyuki Tatsukawa; Hiroki Chikumi; Shingo Matsumoto; Takanori Sako; Yasuyuki Hasegawa; Ryota Okazaki; Kazunori Horasaki; Eiji Shimizu

BACKGROUND Severe wind storms during spring in East Asia, called Asian dust storms (ADS), have been assessed in the past for their effect on health in Asian countries. Our objective was to study the ADS association with asthma symptoms in adult patients in Japan. METHODS We designed a telephone survey to assess ADS influence on upper and lower respiratory, ocular and cutaneous symptoms in 98 patients with adult asthma from April to May 2007. Peak expiratory flow (PEF) was also measured from February to May. RESULTS Worsening lower respiratory symptoms were noted by 22 of 98 patients during ADS in April, when Japanese cedar pollen levels also increased. During ADS in May, however, Japanese cedar and cypress pollen levels were not elevated, 11 patients had worsening of lower respiratory symptoms. None required emergency treatment for the exacerbation. Lower respiratory symptoms worsening most were cough and sputum; this was more common in patients with allergic rhinitis or atopy than in those without (P < 0.05). Min%Max differed significantly at 88.7 ± 6.6% during dust dispersion period, defined as the ADS day plus the next 6 days, versus 92.0 ± 5.3% during the 7-day period before a dust storm. CONCLUSIONS We found that ADS aggravated lower respiratory symptoms in adult patients with asthma, but this influence was mild.BACKGROUND Severe wind storms during spring in East Asia, called Asian dust storms (ADS), have been assessed in the past for their effect on health in Asian countries. Our objective was to study the ADS association with asthma symptoms in adult patients in Japan. METHODS We designed a telephone survey to assess ADS influence on upper and lower respiratory, ocular and cutaneous symptoms in 98 patients with adult asthma from April to May 2007. Peak expiratory flow (PEF) was also measured from February to May. RESULTS Worsening lower respiratory symptoms were noted by 22 of 98 patients during ADS in April, when Japanese cedar pollen levels also increased. During ADS in May, however, Japanese cedar and cypress pollen levels were not elevated, 11 patients had worsening of lower respiratory symptoms. None required emergency treatment for the exacerbation. Lower respiratory symptoms worsening most were cough and sputum; this was more common in patients with allergic rhinitis or atopy than in those without (P <0.05). Min%Max differed significantly at 88.7 ± 6.6% during dust dispersion period, defined as the ADS day plus the next 6 days, versus 92.0 ± 5.3% during the 7-day period before a dust storm. CONCLUSIONS We found that ADS aggravated lower respiratory symptoms in adult patients with asthma, but this influence was mild.


The Journal of Allergy and Clinical Immunology | 2009

Expression of functional leukotriene B4 receptors on human airway smooth muscle cells

Satoko Watanabe; Akira Yamasaki; Kiyoshi Hashimoto; Yasushi Shigeoka; Hiroki Chikumi; Yasuyuki Hasegawa; Takashi Sumikawa; Miyako Takata; Ryota Okazaki; Masanari Watanabe; Tsuyoshi Yokogawa; Miki Yamamura; Tatsuya Hayabuchi; William T. Gerthoffer; Andrew J. Halayko; Eiji Shimizu

BACKGROUND Leukotriene B4 (LTB4) increases in induced sputum and exhaled breath condensate in people with asthma. Furthermore, the T(H)2-type immune response and airway hyperresponsiveness induced by ovalbumin sensitization is markedly suppressed in LTB4 receptor (BLT) 1 null mice. These studies suggest that LTB4 may contribute to asthma pathophysiology. However, the direct effects of LTB4 on human airway smooth muscle (ASM) have not been studied. OBJECTIVES We sought to determine the expression of LTB4 receptors on human ASM and its functional role in mediating responses of human ASM cells, and the effect of LTB4 on these cells. METHODS Immunohistochemistry, RT-PCR, Western blotting, and flow cytometry were used to determine the expression of LTB4 receptors. To determine the effect of LTB4 on human ASM cells, cell proliferation was assessed by counting cells, and chemokinesis was assessed by gold particle phagokinesis assay. RESULTS We confirmed expression of both BLT1 and BLT2 in human ASM cells in bronchial tissue and in cell culture. LTB4 markedly induced cyclin D1 expression, proliferation, and chemokinesis of human ASM cells. LTB4 also induced phosphorylation of both p42/p44 mitogen-activated protein kinase (MAPK) and downstream PI3 kinase effector, Akt1. However, we observed no induction of c-Jun N-terminal kinase or p38 MAPK. Notably, LTB4-induced migration and proliferation of ASM cells were inhibited by the BLT1 specific antagonist, U75302, and by inhibitors of p42/p44 MAPK phosphorylation (U1026), and PI3 kinase (LY294002). CONCLUSIONS These observations are the first to suggest a role for a LTB4-BLT1 signaling axis in ASM responses that may contribute to the pathogenesis of airway remodeling in asthma.


International Journal of Environmental Health Research | 2009

Environmental tobacco smoke and its effect on the symptoms and medication in children with asthma

Akira Yamasaki; Keichi Hanaki; Katsuyuki Tomita; Masanari Watanabe; Yasuyuki Hasagawa; Ryota Okazaki; Tadashi Igishi; Kenta Horimukai; Kouji Fukutani; Yuji Sugimoto; Mitsunobu Yamamoto; Kazuhiro Kato; Toshikazu Ikeda; Tatsuya Konishi; Hirokazu Tokuyasu; Hiroki Yajima; Hitoshi Sejima; Takeshi Isobe; Eiji Shimizu

Environmental tobacco smoke (ETS) worsens asthmatic symptoms. We analyzed the relationship between levels of ETS and asthmatic symptoms and medication. We asked parents of 282 asthmatic children about the general condition, smoke exposure and medication. Patients were classified into three groups: no-ETS (no smoking), mild-ETS (smoking in the house but not in the same room as patient), and heavy-ETS (smoking in the same room as patient). We classified 116 children in no-ETS group, 124 children in mild-ETS group and 42 children in heavy-ETS group. The symptoms were worst and prevalence of leukotriene receptor antagonist and long-acting β2-agonist use were highest in heavy-ETS group. However, there was no statistical difference between no-ETS and mild-ETS groups in prevalence of anti-asthmatic drug use and symptoms. We conclude that a smoking ban in rooms used by asthmatic children is an easy way to reduce ETS, asthmatic symptoms and the use of anti-asthmatic drugs.


International Journal of Chronic Obstructive Pulmonary Disease | 2010

COPD is frequent in conditions of comorbidity in patients treated with various diseases in a university hospital.

Akira Yamasaki; Kiyoshi Hashimoto; Yasuyuki Hasegawa; Ryota Okazaki; Miki Yamamura; Tomoya Harada; Shizuka Ito; Soichiro Ishikawa; Hiroki Takami; Masanari Watanabe; Tadashi Igishi; Yuji Kawasaki; Eiji Shimizu

Background Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death and loss of disability-adjusted life-years. However, many COPD patients are not diagnosed because of underrecognition or underdiagnosis of this disease among many patients and physicians. One possible reason is underrecognition of spirometry. In this study, we examined the prevalence of airflow limitation and underlying disease in patients with airflow limitation. Methodology From April 2006 to March 2008, patients who had spirometry performed were examined. The original disease of patients, pulmonary function tests, smoking status, and respiratory symptoms were surveyed from their medical records. Results Of all patients who had spirometry performed, 15.8% showed airflow limitation (FEV1/FVC < 0.7). A variety of diseases were observed in patients with airflow limitation. Among all diseases, cardiovascular disease was the highest and gastrointestinal malignant disease had the second highest prevalence in patients with airflow limitation. Conclusion COPD might be frequent in conditions of comorbidity in patients treated for various diseases. Attention should be paid to the possibility of co-existence of COPD and the influence of COPD on these patients.


Pulmonary Pharmacology & Therapeutics | 2015

γ-Tocotrienol reduces human airway smooth muscle cell proliferation and migration.

Tomoya Harada; Akira Yamasaki; Hiroki Chikumi; Kiyoshi Hashimoto; Ryota Okazaki; Miki Takata; Takehito Fukushima; Masanari Watanabe; Jun Kurai; Andrew J. Halayko; Eiji Shimizu

AIMS Vitamin E is an antioxidant that occurs in 8 different forms (α, β, γ, and δ tocopherol and tocotrienol). Clinical trials of tocopherol supplementation to assess the impact of antioxidant activity in asthma have yielded equivocal results. Tocotrienol exhibits greater antioxidant activity than tocopherol in several biological phenomena in vivo and in vitro. We tested the effect of tocotrienol on human airway smooth muscle (ASM) cell growth and migration, both of which mediate airway remodeling in asthma. MAIN METHODS We measured platelet-derived growth factor-BB (PDGF-BB)-induced ASM cell proliferation and migration by colorimetric and Transwell migration assays in the presence and absence of γ-tocotrienol (an isoform of tocotrienol). KEY FINDINGS PDGF-BB-induced ASM cell proliferation and migration were inhibited by γ-tocotrienol. This effect was associated with inhibition of RhoA activation, but it had no effect on p42/p44 mitogen-activated protein kinase (MAPK) or Akt1 activation. We confirmed that pharmacological inhibition of Rho kinase activity was sufficient to inhibit PDGF-BB-induced ASM cell proliferation and migration. SIGNIFICANCE γ-Tocotrienol could impart therapeutic benefits for airway remodeling in asthma by inhibiting human ASM cell proliferation and migration.


World Journal of Gastrointestinal Oncology | 2010

Gastric metastasis by primary lung adenocarcinoma

Ryota Okazaki; Hideyuki Ohtani; Kenichi Takeda; Takashi Sumikawa; Akira Yamasaki; Shingo Matsumoto; Eiji Shimizu

The diagnosis of gastric metastasis from lung cancer is relatively rare in living patients. We describe a case of Type 4 tumor-like metastasis due to primary lung cancer diagnosed with immunohistochemical staining while the patient was alive. A 68-year-old man was admitted to our hospital because of epigastric pain. Gastrointestinal endoscopy revealed a Type 4 tumor and the histological examination showed poorly differentiated adenocarcinoma. His chest X-ray showed mass shadow in the right upper lung field. The resected specimens showed moderately differentiated adenocarcinoma., The diagnosis of gastric metastasis from lung cancer was made by immunohistochemical staining of the lung and gastric tumors which showed positive staining for Thyroid transcriptional factor-1. Diagnosis of gastric metastasis, especially Type 4 metastasis by lung cancer is difficult. However, immunohistochemical staining is very helpful for diagnosis of primary lung cancer metastasis at sites such as the gastrointestinal tract which are not normally prone to metastatis.


International Journal of Chronic Obstructive Pulmonary Disease | 2015

Causes of death in patients with asthma and asthma–chronic obstructive pulmonary disease overlap syndrome

Tomoya Harada; Akira Yamasaki; Takehito Fukushima; Kiyoshi Hashimoto; Miki Takata; Masahiro Kodani; Ryota Okazaki; Kenichi Takeda; Masanari Watanabe; Jun Kurai; Eiji Shimizu

Background The administration of inhaled corticosteroids and worldwide usage of several asthma guidelines have improved asthma mortality. Elderly patients with asthma show high mortality rates, and may have several comorbidities, including overlap with chronic obstructive pulmonary disease (COPD). Among patients showing asthma overlapped with COPD (asthma–COPD overlap syndrome; ACOS), mortality is worse than for asthma alone. Therefore, we investigated comorbidities, malignancies, and causes of death in patients with asthma and ACOS. Methods This was a retrospective study. From January 2000 to March 2012, 650 patients were followed up at Tottori University Hospital. Medical records were reviewed to collect data regarding patient characteristics and comorbidities, and causes of death were recorded for patients who died during the study period. Results Eighty-seven patients died during the study period. The most frequent cause of death was malignancy. The proportion of malignant disease was 21.7% in all patients, 19.4% in patients with asthma alone, and 32.4% in patients with ACOS. One patient died from an asthma attack during this period. Conclusion The most frequent cause of death in patients with asthma and ACOS was malignant disease. It is necessary to control not only asthma but also comorbidities in patients with asthma, especially in those with ACOS.


Lung | 2007

Sjogren's Syndrome with Multiple Bullae Caused by Lymphocytic Interstitial Pneumonia

Hirokazu Tokuyasu; Etsuko Watanabe; Ryota Okazaki; Yuji Kawasaki; Ryutaro Kikuchi; Noritaka Isowa; Hideyuki Ohnuma; Hiroshi Miura; Eiji Shimizu; Yoichiro Kobashi

The mechanism of parenchymal bulla formation is poorly understood. It has been postulated that the mechanism of bullae formation probably involves inflammatory cell infiltration into the bronchial wall, resulting in narrowing of the airways. Thus, cell infiltration acts as a check valve mechanism [1]. Although several pulmonary disorders have been described in patients with Sjogren’s syndrome, cystic or bullous lung disease is rare [2]. Because our patient was of child-bearing age and a nonsmoker, we needed to determine whether the bullae was associated with Sjogren’s syndrome or caused by lymphangioleiomyomatosis (LAM). The bullae that are characteristic of LAM are 5–15 mm in diameter, have thin walls, and are homogeneously


International Journal of General Medicine | 2010

Cough and asthma diagnosis: physicians’ diagnosis and treatment of patients complaining of acute, subacute and chronic cough in rural areas of Japan

Akira Yamasaki; Keichi Hanaki; Katsuyuki Tomita; Masanari Watanabe; Yasuyuki Hasagawa; Ryota Okazaki; Miki Yamamura; Kouji Fukutani; Yuji Sugimoto; Kazuhiro Kato; Masahiro Kodani; Toshikazu Ikeda; Tatsuya Konishi; Yuji Kawasaki; Hirokazu Tokuyasu; Hiroki Yajima; Hitoshi Sejima; Takeshi Isobe; Eiji Shimizu

Background: Cough is one of the most common reasons for visiting a clinic. The causes of cough differ according to the duration of cough. Infectious disease is commonly observed in acute cough while noninfectious disease is commonly observed in chronic cough. On the other hand, cough is frequently observed in patients with asthma/cough variant asthma (CVA). Objective: In this study, we investigated the causes of cough in a rural region in Japan and the clinical examination and treatment for the patients diagnosed as asthma/CVA. Methods: We analyzed 124 patients who complained of cough. Results: The most common reason for acute cough was respiratory tract infection while asthma/CVA is the most common reason for subacute and chronic cough. The diagnostic procedure for asthma/CVA depends on clinical symptoms in asthmatic patients with acute cough. While in asthmatic patients with subacute and chronic cough, diagnosis of asthma depends on clinical examinations including chest radiogram, immunoglobulin E, white blood cells counts, sputum examination or spirometry as well as symptoms. For the treatment of asthma, the use of long-acting β2-stimulant was dominant in asthmatic patients with acute cough while the use of leukotriene receptor and inhaled corticosteroid were dominant in asthmatic patients with subacute or chronic cough. Conclusions: Diagnosis and treatment for asthma differs according to the duration of cough. Simple guidelines for asthma/CVA according to the duration of cough might be necessary for diagnosis and treatment of asthma/CVA for general physicians especially in rural areas.


Respiratory medicine case reports | 2018

An onion farmer with a case of hypersensitivity pneumonitis caused by Aspergillus niger

Tomohiro Sakamoto; Akira Yamasaki; Yoshihiro Funaki; Tomoya Harada; Ryota Okazaki; Yasuyuki Hasegawa; Yuriko Sueda; Takehito Fukushima; Masahito Morita; Akihiro Yamamoto; Masahiro Kodani; Eiji Shimizu

A 62-year old man was admitted to our hospital with a 2-week complaint of a dry cough, general fatigue, and dyspnea on effort. He has been an onion farmer for several years and developed these symptoms after cleaning up onion peels with air compressors. A chest roentgenogram and computed tomography showed a ground glass shadow in the bilateral upper lung field. Cellular analysis of the bronchoalveolar lavage fluid showed elevated total cell numbers and lymphocytes. Transbronchial lung biopsies revealed a non-caseating granuloma with both epithelioid cells and Langhans giant cells. After the admission, these symptoms and radiological findings gradually improved without any treatment. Then, a returning-home provocation test was positive only when he worked cleaning up onion peels with air compressors. A. niger was cultured from his workplace and black mold from the onion peels. The precipitation antibody and the antigen were both positive for Aspergillus. Therefore, we diagnosed this case as hypersensitivity pneumonitis caused by inhalation of A. niger. Although hypersensitivity pneumonia caused by A. niger is rare, physicians should aware the possibility of this condition in farmers because A niger is ubiquitously present in several vegetables and fruits.

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