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Featured researches published by Toru Ozawa.


Internal Medicine | 2016

A Simultaneous Evaluation of Occupational Stress and Depression in Patients with Lifestyle-related Diseases.

Nobutaka Inoue; Kazunori Otsui; Takayuki Yoshioka; Atsushi Suzuki; Toru Ozawa; Sachiyo Iwata; Asumi Takei

Objective Karoshi, which is the Japanese term for death from over-work, is usually the extreme result of cardiovascular diseases, and occupational stress plays a pivotal role in the pathogenesis. Depression is closely associated with atherosclerotic cardiovascular disease. The present study was undertaken to examine the relationship between occupational stress and depression. Methods We enrolled 231 consecutive outpatients with lifestyle-related diseases such as diabetes, hyperlipidemia and hypertension were enrolled. Occupational stress was measured by qualitative constructs assessing job control, job demands, and worksite social support using a job content questionnaire (JCQ). The job strain index measured by the ratio of job demands to job control was used as an indicator of the occupational stress. Depression was evaluated by the Self-rating Depression Scale (SDS). Results A univariate linear regression analysis showed the SDS scores to be positively correlated with job demands and the job strain index and negatively correlated with job control and worksite social support. Multiple regression analyses to predict the SDS scores demonstrated that job demands were positively associated with SDS scores and job control and worksite social support were negatively associated with SDS scores after controlling for other variables. The job strain index was positively related to SDS scores. Conclusion Occupational stress expressed as the job strain index was strongly associated with depression. By simultaneously using the SDS and JCQ, the health conditions of patients could be classified based on occupational stress and mental stress, and this classification could help to promote a healthy work environment and guide individual workers.


Journal of Cardiology | 2015

Effects of human atrial natriuretic peptide on myocardial performance and energetics in heart failure due to previous myocardial infarction.

Toru Ozawa; Toshiro Shinke; Junya Shite; Hideyuki Takaoka; Nobutaka Inoue; Hidenari Matsumoto; Satoshi Watanabe; Ryohei Yoshikawa; Hiromasa Otake; Daisuke Matsumoto; Daisuke Ogasawara; Mitsuhiro Yokoyama; Ken-ichi Hirata

BACKGROUND Human atrial natriuretic peptide (hANP) and spontaneous nitric oxide (NO) donor share cyclic guanosine monophosphate (cGMP) as a second messenger, but their effect on myocardium may differ. We compared the effect of hANP and sodium nitroprusside (SNP) on left ventricular (LV) mechano-energetics in heart failure (HF). METHODS Ten patients with HF due to previous myocardial infarction (LV ejection fraction: 45±3%) were instrumented with conductance and coronary sinus thermodilution catheters. LV contractility (Ees: slope of end-systolic pressure-volume relation) and the ratio of LV stroke work (SW) to myocardial oxygen consumption (SW/MVO2=mechanical efficiency) were measured in response to intravenous infusion of ANP (0.05 μg/kg/min) or SNP (0.3 μg/kg/min) to lower blood pressure by at least 10 mmHg, and changes in plasma cGMP. RESULTS SNP had no effect on Ees, SW, or MVO2, thus SW/MVO2 remained unchanged (40.54±5.84% to 36.59±5.72%, p=0.25). ANP increased Ees, and decreased MVO2 with preserved SW, resulting in improved SW/MVO2 (40.49±6.35% to 50.30±7.96%, p=0.0073). Infusion of ANP (10.42-34.95 pmol/ml, p=0.0003) increased cGMP levels, whereas infusion of SNP had no effect (10.42-12.23 pmol/ml, p=0.75). CONCLUSIONS Compared to SNP, the ANP-dependent increase in cGMP may ameliorate myocardial inotropy and energetics in HF.


American Journal of Case Reports | 2015

Coconut Atrium in Long-Standing Rheumatic Valvular Heart Disease

Takahisa Onishi; Yuka Idei; Kazunori Otsui; Sachiyo Iwata; Atsushi Suzuki; Toru Ozawa; Koji Domoto; Asumi Takei; Shinya Inamoto; Nobutaka Inoue

Patient: Male, 76 Final Diagnosis: Rheumatic valvular heart disease Symptoms: Breathlessness and leg edema Medication: — Clinical Procedure: Medical treatment for heart failure Specialty: Cardiology Objective: Rare disease Background: Complete calcification of the left atrium (LA) is called “coconut atrium”, which decreases the compliance of LA, leading to the elevation of LA pressure that is transmitted to the right-side of the heart. The pathogenesis of LA calcification in patients with rheumatic heart disease is unknown; however, possible mechanisms include chronic strain force in the atrial wall and inflammation. We report here a patient with long-standing rheumatic valvular heart disease with coconut atrium. Case Report: A 76-year-old man presented with breathlessness and leg edema due to right-sided heart failure. He was diagnosed with rheumatic fever at 8 years of age. Mitral commissurotomy and the mitral and aortic valve replacement were previously performed to treat mitral and aortic valvular stenosis. The profile view of the chest X-ray indicated a diffuse calcified outline of the LA wall. A transthoracic echocardiogram revealed pulmonary hyper-tension and dilatation of both atria. Moreover, computed tomography showed nearly circumferential calcification of the LA wall. Despite intense medical treatment, he succumbed to heart failure. An autopsy demonstrated that the LA was markedly dilated, its wall was calcified, and its appearance was similar to the surface of an atherosclerotic aorta. Microscopic examination revealed intensive calcification in the endocardium. Minimal accumulation of inflammatory cells was noted. Although slight fibrosis was observed, the cardiac musculature was preserved. Conclusions: To the best of our knowledge, this is the first report that identifies the histological changes of LA calcification associated with long-standing rheumatic valvular heart disease.


American Journal of Case Reports | 2017

A Case with Recurrent Free-Floating Ball Thrombi in Left Atrium

Takayuki Yoshioka; Takeshige Mori; Yayoi Taniguchi; Sonoko Hirayama; Toru Ozawa; Sachiyo Iwata; Asumi Takei; Nobutaka Inoue

Patient: Female, 74 Final Diagnosis: Left atrial ball thrombus Symptoms: Abdominal discomfort • dyspnea Medication: — Clinical Procedure: — Specialty: Cardiology Objective: Rare disease Background: A free-floating ball thrombus in the left atrium is a rare clinical condition. However, the diagnosis of this condition has been facilitated by the advent and development of echocardiography and multi-detector row computed tomography (MDCT) and several cases have been reported. Case Report: We report a case of a 75-year-old woman who had recurrent giant spherical thrombi in the left atrium. She was diagnosed with chronic atrial fibrillation at 52 years of age. A pacemaker implantation was performed at 54 years of age because of a complete atrioventricular block; and mitral valve replacement was performed for severe mitral regurgitation at 62 years of age. She had a history of cerebral infarction and she was under treatment for chronic heart failure. Despite intensive anticoagulant therapy, she developed ball thrombi in the left atrium three times in six months. During hospitalization for acute myocardial infarction treated with percutaneous catheter intervention, transthoracic echocardiography and computed tomography (CT) revealed a free-floating giant spherical thrombus in the left atrium. She was treated with intensive anticoagulation therapy and the left atrial ball thrombus disappeared; however, two ball thrombi in the left atrium and left atrial appendage recurred after three months. Surgical removal of the thrombi and closure of the left atrial appendage were performed. Unfortunately, a ball thrombus in the left atrium recurred again after a further three months. Conclusions: The present case highlights the difficulty of treating refractory thrombi in the left atrium.


Journal of Cardiology Cases | 2015

A super-elderly case of abdominal aortic aneurysm associated with chronic disseminated intravascular coagulation

Kazunori Otsui; Mai Yamamoto; Humiaki Aoki; Toru Ozawa; Koji Domoto; Atsushi Suzuki; Sachiyo Iwata; Asumi Takei; Shinya Inamoto; Nobutaka Inoue

Chronic disseminated intravascular coagulation (DIC) is a well-known complication of aortic aneurysm. A 91-year-old Japanese woman was admitted to our hospital because of massive purpura of the lower limbs. The presence of abdominal aortic aneurysm (AAA) had been pointed out from the age of 80 years, and its diameter had gradually increased. The AAA was composed of two portions, that is, a large upper and a small lower portion, and a large mural thrombosis was observed in the lower portion. The laboratory data led to the diagnosis of DIC, and AAA was the only identifiable cause of coagulopathy. The time course of exacerbation of AAA was consistent with the progression of thrombocytopenia and purpura. Therefore, we concluded that AAA was the underlying cause of DIC. Since DIC in aortic aneurysms is associated with excessive fibrinolysis, tranexamic acid was administered as anti-fibrinolytic therapy. After that, coagulopathy was drastically improved. Our patient responded successfully to anti-fibrinolytic therapy for coagulopathy. The present case illustrates the importance of evaluation of the diameter of an aneurysm as well as intraluminal thrombosis, which may play an important role in coagulopathy including DIC. It is necessary to monitor coagulation and fibrinolysis for the follow-up of patients with AAA. <Learning objective: We present a case report of an aged Japanese woman with abdominal aortic aneurysm associated with disseminated intravascular coagulation, and anti-fibrinolytic therapy drastically ameliorated her condition. Our case illustrates the importance of evaluation of the diameter of an aneurysm as well as conducting follow-up monitoring of coagulation and fibrinolysis.>.


American Journal of Case Reports | 2015

Vasospastic Angina in Identical Twins

Takayuki Yoshioka; Kazunori Otsui; Atsushi Suzuki; Toru Ozawa; Sachiyo Iwata; Asumi Takei; Nobutaka Inoue

Patient: Male, 58 Final Diagnosis: Vasospastic angina Symptoms: Chest pain Medication: — Clinical Procedure: Medical treatment Specialty: Cardiology Objective: Rare disease Background: The clinical conditions of various diseases, including coronary artery disease, are determined by genetics and the environment. Previous investigations noted the significance of genetic mutations and polymorphisms in cases of coronary spasm. Case Report: We report on monozygotic identical twins who almost simultaneously presented with vasospastic angina. The 58-year-old younger twin was admitted to our hospital because of persistent chest pain. An electrocardiogram showed an inverted T wave in the left precordial leads. Coronary angiographies revealed a short left main trunk (LMT) and 50% stenosis at the proximal portion of the left anterior descending artery (LAD). Infusion of acetylcholine to his left coronary artery caused marked vasoconstriction associated with a sensation of chest oppression. Nitroglycerine completely reversed this response. Based on these findings, we diagnosed Twin A with vasospastic angina. At nearly the same time, his identical twin brother was diagnosed with vasospastic angina at another hospital. Comparison of both coronary angiograms indicated similar structure of coronary vessels, including short LMT and mild stenosis at the proximal portion of LAD. Conclusions: These 2 cases highlight the importance of genetic factors in the pathogenesis of vasospastic angina. It may be important for individuals to receive medical attention if their identical twin presents with vasospastic angina.


European Heart Journal | 2006

Myocardial stiffness is an important determinant of the plasma brain natriuretic peptide concentration in patients with both diastolic and systolic heart failure

Satoshi Watanabe; Junya Shite; Hideyuki Takaoka; Toshiro Shinke; Yusuke Imuro; Toru Ozawa; Hiromasa Otake; Daisuke Matsumoto; Daisuke Ogasawara; Oscar Luis Paredes; Mitsuhiro Yokoyama


Journal of the American College of Cardiology | 2007

Catheter-Based Transcoronary Myocardial Hypothermia Attenuates Arrhythmia and Myocardial Necrosis in Pigs With Acute Myocardial Infarction

Hiromasa Otake; Junya Shite; Oscar Luis Paredes; Toshiro Shinke; Ryohei Yoshikawa; Yusuke Tanino; Satoshi Watanabe; Toru Ozawa; Daisuke Matsumoto; Daisuke Ogasawara; Mitsuhiro Yokoyama


Clinical Cardiology | 2004

Depletion of antioxidants is associated with no-reflow phenomenon in acute myocardial infarction.

Hidenari Matsumoto; Nobutaka Inoue; Hideyuki Takaoka; Katsuya Hata; Toshiro Shinke; Ryohei Yoshikawa; Hiroyuki Masai; Satoshi Watanabe; Toru Ozawa; Mitsuhiro Yokoyama


Thrombosis Journal | 2015

Global Thrombosis Test – a possible monitoring system for the effects and safety of dabigatran

Kazunori Otsui; Diana A. Gorog; Junichiro Yamamoto; Takayuki Yoshioka; Sachiyo Iwata; Atsushi Suzuki; Toru Ozawa; Asumi Takei; Nobutaka Inoue

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Atsushi Suzuki

National Institute of Advanced Industrial Science and Technology

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