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Dive into the research topics where Mitsuaki Sekiya is active.

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Featured researches published by Mitsuaki Sekiya.


American Journal of Physiology-lung Cellular and Molecular Physiology | 2010

Complete lack of vitamin C intake generates pulmonary emphysema in senescence marker protein-30 knockout mice

Kengo Koike; Yoshitaka Kondo; Mitsuaki Sekiya; Yasunori Sato; Kazunori Tobino; Shin Iciro Iwakami; Sataro Goto; Kazuhisa Takahashi; Naoki Maruyama; Kuniaki Seyama; Akihito Ishigami

Vitamin C (VC) is a potent antioxidant and plays an essential role in collagen synthesis. As we previously reported, senescence marker protein-30 (SMP30) knockout (KO) mice cannot synthesize VC due to the genetic disruption of gluconolactonase (i.e., SMP30). Here, we utilized SMP30 KO mice deprived of VC and found that VC depletion caused pulmonary emphysema due to oxidative stress and a decrease of collagen synthesis by the third month of age. We grew SMP30 KO mice and wild-type (WT) mice on VC-free chow and either VC water [VC(+)] or plain water [VC(-)] after weaning at 4 wk of age. Morphometric findings and reactive oxygen species (ROS) in the lungs were evaluated at 3 mo of age. No VC was detected in the lungs of SMP30 KO VC(-) mice, but their ROS increased 50.9% over that of the VC(+) group. Moreover, their collagen content in the lungs markedly decreased, and their collagen I mRNA decreased 82.2% compared with that of the WT VC(-) group. In the SMP30 KO VC(-) mice, emphysema developed [21.6% increase of mean linear intercepts (MLI) and 42.7% increase of destructive index compared with VC(+) groups], and the levels of sirtuin 1 (Sirt1) decreased 16.8%. However, VC intake increased the MLI 16.2% and thiobarbituric acid reactive substances 22.2% in WT mice, suggesting that an excess of VC can generate oxidative stress and may be harmful during this period of lung development. These results suggest that VC plays an important role in lung development through affecting oxidant-antioxidant balance and collagen synthesis.


Lung | 2003

Serum vascular endothelial growth factor as a possible prognostic indicator in sarcoidosis.

Mitsuaki Sekiya; Akihiko Ohwada; Kayo Miura; S. Takahashi; Yoshinosuke Fukuchi

Sarcoidosis is a systemic granulomatous disorder of unknown etiology, which involves the lung, eye, liver, and other organs. Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis involved in an important role in the development of granuloma. However, only a limited number of studies have reported on the relationship between serum VEGF values and the clinical status of sarcoidosis. Concentrations of serum VEGF were determined in 33 patients with sarcoidosis. We investigated the correlation between serum VEGF values and extent of disease, prognosis, and radiographic stage compared with serum angiotensin converting enzyme (ACE) values as another candidate. Concentrations of serum VEGF in patients who received corticosteroid treatment were significantly higher than those of patients with spontaneous remission (p < 0.05). In addition, serum VEGF values in patients with extrathoracic involvements were significantly higher than those of patients with sarcoid lesions limited to the thoracic space (p < 0.05), accompanied by a tendency to increase the number of organs involved. The values of serum ACE revealed no relationship to the values of serum VEGF, administration of corticosteroid, or extrathoracic involvements. We concluded that serum VEGF values in patients with sarcoidosis is a predictive factor in determining extrathoracic organ involvements and as a parameter for deciding the necessity of treatment with corticosteroid. Serum VEGF might be a useful marker as a prognostic indicator in sarcoidosis.


American Journal of Respiratory Cell and Molecular Biology | 2013

Vitamin C Prevents Cigarette Smoke–Induced Pulmonary Emphysema in Mice and Provides Pulmonary Restoration

Kengo Koike; Akihito Ishigami; Yasunori Sato; Toyohiro Hirai; Yiming Yuan; Etsuko Kobayashi; Kazunori Tobino; Tadashi Sato; Mitsuaki Sekiya; Kazuhisa Takahashi; Yoshinosuke Fukuchi; Naoki Maruyama; Kuniaki Seyama

Vitamin C (VC) is a potent antioxidant and is essential for collagen synthesis. We investigated whether VC treatment prevents and cures smoke-induced emphysema in senescence marker protein-30 knockout (SMP30-KO) mice, which cannot synthesize VC. Two smoke-exposure experiments using SMP30-KO mice were conducted. In the first one (a preventive study), 4-month-old mice received minimal VC (0.0375 g/l) [VC(L)] or physiologically sufficient VC (1.5 g/l) [VC(S)] and exposed to cigarette smoke or smoke-free air for 2 months. Pulmonary evaluations followed when the mice were 6 months of age. The second study began after the establishment of smoke-induced emphysema (a treatment study). These mice no longer underwent smoke exposure but received VC(S) or VC(L) treatment for 2 months. Morphometric analysis was performed, and measurements of oxidative stress, collagen synthesis, and vascular endothelial growth factor in the lungs were evaluated. Chronic smoke exposure caused emphysema (29.6% increases of mean linear intercepts [MLI] and 106.5% increases of destructive index compared with the air-only group) in 6-month-old SMP30-KO mice, and this emphysema closely resembled human chronic obstructive pulmonary disease. Smoke-induced emphysema persisted in the VC(L) group after smoking cessation, whereas VC treatment provided pulmonary restoration (18.5% decrease of MLI and 41.3% decrease of destructive index compared with VC(L) group). VC treatment diminished oxidative stress, increased collagen synthesis, and improved vascular endothelial growth factor levels in the lungs. Our results suggest that VC not only prevents smoke-induced emphysema in SMP30-KO mice but also restores emphysematous lungs. Therefore, VC may provide a new therapeutic strategy for treating chronic obstructive pulmonary disease in humans.


Respirology | 2007

Ultrasonographic evaluation of the diaphragm in patients with amyotrophic lateral sclerosis.

Yasuko Yoshioka; Akihiko Ohwada; Mitsuaki Sekiya; Fumiyuki Takahashi; Jun Ueki; Yoshinosuke Fukuchi

Abstract:  Real‐time diaphragmatic movement was evaluated with ultrasonography in three patients with amyotrophic lateral sclerosis (ALS). The initial complaint of two patients was weakness of the extremities followed by dyspnoea later in the disease course, while the third patient had dyspnoea as the initial symptom. Ultrasonographic analyses revealed that the contractile function of the diaphragm was not maintained during maximum inspiratory effort, with unsatisfactory diaphragmatic excursion and no change in diaphragmatic thickness during respiration, indicating diaphragmatic paralysis. Ultrasonography may be useful for the diagnosis and follow up of diaphragmatic involvement with amyotrophic lateral sclerosis and other motor‐neuron diseases.


Respirology | 2002

Adenovirus vector-mediated transfer of 9 kDa granulysin induces DNA fragmentation in HuD antigen-expressing small cell lung cancer murine model cells

Mitsuaki Sekiya; Akihiko Ohwada; Masaharu Katae; Takashi Dambara; Isao Nagaoka; Yoshinosuke Fukuchi

Objective: Granulysin is a tumoricidal molecule secreted by cytotoxic T cells (CTL) and natural killer (NK) cells, that induces apoptotic cell death in tumour cells. It has been demonstrated that small cell lung cancer (SCLC) cell lines are susceptible to NK cells and lymphokine activated killer (LAK) cells, and HuD antigen is assumed to be a target molecule on SCLC cells for host cellular immunity.


Surgery Today | 2010

Thymic adenocarcinoma with sarcomatoid features characterized by intracaval tumor growth: Report of a case

Toshiji Ishiwata; Mitsuaki Sekiya; Tsutomu Suzuki; Takashi Matsuoka; Toshio Kumasaka; Kazuhisa Takahashi

Primary thymic adenocarcinoma is an extremely rare tumor. This report describes a case of thymic adenocarcinoma with a peculiar pathological feature and clinical course. A 54-year-old man complained of cough, dyspnea, and chest pain. Computed tomography scans revealed an anterior mediastinal mass with intracaval growth into the superior vena cava. No definitive diagnosis could be made after several examinations and palliative radiotherapy was performed. He passed away 56 days after the appearance of the initial symptoms. An autopsy revealed that the mediastinal tumor obstructed not only the superior vena cava but also the pulmonary arteries. The histological findings revealed the tumor to be an adenocarcinoma with sarcomatous features. The tumor was immunohistochemically positive for CD5 and negative for thyroid transcription factor-1. These results suggested the tumor to be a thymic adenocarcinoma with sarcomatoid features; furthermore, the tumor invaded the great vessels, thus resulting in a poor prognosis.


Respiratory investigation | 2015

Do respiratory comorbidities limit the diagnostic usefulness of ultrasound-guided needle aspiration for subpleural lesions?

Mitsuaki Sekiya; Kaku Yoshimi; Keiko Muraki; Shin-ichiro Iwakami; Shinsaku Togo; Shigeru Tamaki; Takashi Dambara; Kazuhisa Takahashi

BACKGROUND The usefulness of ultrasound-guided needle aspiration for subpleural lesions has been reported. However, no reports have evaluated its usefulness and safety in patients with respiratory comorbidities such as chronic obstructive pulmonary disease (COPD) and interstitial pneumonia (IP), which can increase the risk of iatrogenic pneumothorax. In this study, we evaluated the influence of chronic respiratory diseases (CRDs) on the usefulness and safety of ultrasound-guided needle aspiration for subpleural lesions. METHODS Between January 2000 and September 2011, we examined 144 patients with intrapulmonary subpleural lesions. We retrospectively reviewed clinical data, including lesion size on thoracic computed tomography (CT), ultrasound findings, pathological findings obtained by ultrasound-guided needle aspiration, final diagnosis, and complications. RESULTS A positive definitive diagnosis was obtained in 74.3% of all 144 patients; 84.7% patients with malignant diseases, including lung cancer; and 26.9% patients with benign diseases. Of the 144 patients, 64 belonged to the CRD group and 80 to the non-CRD group. The former included 31 patients with COPD, six with emphysematous changes on thoracic CT, 17 with IP, and 10 with other diseases. The positive rate of diagnosis for malignant diseases was 84.7% in the CRD group, which was the same as that in the non-CRD group. With regard to complications related to ultrasound-guided aspiration, there were only two cases of pneumothorax in the CRD group and one in the non-CRD group. CONCLUSION Ultrasound-guided aspiration is safe and useful for subpleural lesions, particularly malignant lesions, even in patients with respiratory comorbidities such as COPD and IP.


Annals of Thoracic and Cardiovascular Surgery | 2016

Impact of Airflow Limitation on Comorbidities and Postoperative Complications in Patients Undergoing Thoracic Surgery: A Retrospective Observational Study

Kaku Yoshimi; Shiaki Oh; Kenji Suzuki; Yuzo Kodama; Mitsuaki Sekiya; Kuniaki Seyama; Yoshinosuke Fukuchi

PURPOSE To assess the frequency of airflow limitation (AFL), and the relationship between AFL and preoperative comorbidities or postoperative complications in patients who had undergone thoracic surgery. METHODS The medical records of patients who underwent non-cardiac thoracic surgery at our institution between August 1996 and January 2013 were retrospectively reviewed. On the basis of preoperative pulmonary function tests, patients were classified with those with FEV1/FVC <70% [AFL(+) group] or with FEV1/FVC ≥70% [AFL(-) group]. Patient characteristics, preoperative comorbidities and postoperative complications were compared between the groups. RESULTS Of the 3667 patients assessed, 738 (20.1%) were allocated to the AFL(+) group. AFL was an independent risk factor for three preoperative comorbidities: chronic obstructive pulmonary disease (odds ratio [OR]: 4.65), bronchial asthma (OR 4.30) and cardiac diseases (OR 1.41). Airflow limitation was also an independent risk factor for postoperative respiratory failure including long-term oxygen therapy (OR 2.14) and atelectasis (OR 1.90) in the patients who underwent lobectomy or partial resection of the lung. CONCLUSIONS Our retrospective study revealed that careful attention needs to be paid to airflow limitation in patients who undergo non-cardiac thoracic surgery since it appears to be an important feature of preoperative comorbidities and to increase postoperative complications.


Respiratory investigation | 2013

Solitary fibrous tumor of the pleura: Ultrasonographic imaging findings of 3 cases

Mitsuaki Sekiya; Kaku Yoshimi; Keiko Muraki; Kenji Suzuki; Takashi Dambara; Toshimasa Uekusa; Kazuhisa Takahashi

Solitary fibrous tumor (SFT) of the pleura is a rare tumor of mesenchymal origin. Although radiographic findings of thoracic computed tomography and magnetic resonance imaging in the evaluation of SFTs of the pleura have been documented, the value of ultrasonography is uncertain. We presented the ultrasonographic findings of 3 pathologically proven cases of SFTs arising from the visceral pleura. In all the cases, thoracic ultrasonography demonstrated homogeneous, hypoechoic, hemicycle, extrapulmonary lesions, which showed respiratory movement with the adjacent lung, consistent with pedunculated tumors. Preoperative thoracic ultrasonography could be useful in the evaluation of patients with pleural tumors, especially SFTs.


Journal of Medical Case Reports | 2012

Malignant lymphoma with diffuse cardiac involvement detected by multiple imaging examinations: a case report

Toshiji Ishiwata; Norihiro Harada; Ryo Ko; Munechika Hara; Mitsuaki Sekiya; Makoto Sasaki; Bunsei Nobukawa; Kazuhisa Takahashi

IntroductionIn malignant lymphoma, cardiac involvement, which usually forms pathologically focal and firm nodules in the cardiac walls, is considered to be a late manifestation of the disease.Case presentationWe describe the case of a 71-year-old Asian Japanese woman whose first presentation of lymphoma was congestive heart failure. Multiple imaging examinations and laboratory findings led to a presumed diagnosis of a malignant lymphoma. A tissue diagnosis of the mediastinal mass could not be performed due to our patient’s generally poor condition. Our patient received corticosteroid therapy, but died 42 days after her admission. An autopsy revealed lymphoid cells encircling her ventricular wall and infiltrating her endocardium. A histological examination confirmed the diagnosis of diffuse large B-cell lymphoma.ConclusionImaging examinations such as echocardiography, computed tomography with three-dimensional reconstruction, and gallium-67-citrate scintigraphy could clearly detect the diffuse cardiac involvement antemortem. A combination of these imaging techniques could provide a working diagnosis and allow empirical initiation of treatment in patients with poor general condition.

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