Publications by authors named "Masatoshi Miyamura"

The matrix in the "Allende meteorite" was analyzed by high-spatial-resolution focused ion beam time-of-flight secondary ion mass spectrometry (FIB-TOF-SIMS), and consisted of fine grains with sizes of several micrometers. It is difficult to analyze the matrix particles individually. As FIB-TOF-SIMS has a high spatial resolution, it can analyze the matrix individually.

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Background: Thrombogenic milieu (TM) within the left atrium plays a pivotal role in the pathogenesis of thromboembolic events, for which anticoagulation treatment is indicated typically on the mandatory basis. Little is known, however, about which regimen of anticoagulation, warfarin or direct oral anticoagulants (DOACs), is more likely associated with TM. We evaluated relative relationship of the two treatment options with concurrently-observed TM in patients with nonvalvular atrial fibrillation (AF) who underwent transesophageal echocardiography.

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BACKGROUND The left atrial appendage (LAA) has considerable variations in its size, shape, and spatial relationship with other cardiac structures. Absence of the LAA is a congenital cardiac condition usually identified by an imaging modality intended for other purposes. Absence of the LAA has been described in a total of 19 case reports so far; however, no cases of "hypoplastic" LAA in a real sense have ever been reported.

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Background: Left atrial spontaneous echo contrast (LASEC) is common in patients with atrial fibrillation (AF), although scarce information exists on LASEC occurring in nonvalvular AF patients who have low thromboembolic risk scores. We therefore examined prevalence and determinants of LASEC under low CHADS or CHADS-VASc scores in these patients.

Methods: Among 713 patients who underwent transesophageal echocardiography, 349 with a CHADS score < 2 (CHADS group) (93 women, mean age 65 years) and 221 with a CHADS-VASc score < 2 (CHADS-VASc group) (39 women, mean age 62 years) were separately examined for clinical and echocardiographic findings.

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Background: Tissue Doppler imaging (TDI)-derived atrial electromechanical delay (AEMD) has been reported to be useful for detecting paroxysmal atrial fibrillation (PAF). However, its usefulness remains unknown when analyzed along with patients seemingly at high-risk for AF as controls. From this standpoint, we investigated whether AEMD would be of use for identifying patients with PAF.

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We herein report a woman diagnosed with cardiac sarcoidosis (CS) based on the presence of epithelioid granulomas in non-cardiac organs and clinical findings including sustained ventricular tachycardia (VT) and cardiac dysfunction. She stopped oral corticosteroid after 4 years of treatment, and an abnormal myocardial uptake of fluorine-18 fluorodeoxyglucose and sustained VT recurred 3.5 years later.

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Severe ventricular arrhythmias such as high-grade atrioventricular block and ventricular tachycardia may cause lethal conditions or sudden death in patients with cardiac sarcoidosis (CS). Physicians should examine patients carefully for these conditions and treat them appropriately. As arrhythmias are being better diagnosed and treated, physicians are increasingly aware of atrial arrhythmias, which have not been focused upon as CS-related conditions, in patients with CS.

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Cardiac sarcoidosis (CS) causes lethal arrhythmia and heart failure and has a poor prognosis; therefore, early detection and early stage treatment are important. However, diagnosis of isolated CS may be difficult in some cases owing to the low sensitivity of myocardial biopsy. Herein, we describe the case of a patient with isolated CS, showing change from negative to positive fluorine-18 fluorodeoxyglucose ( F-FDG) positron emission tomography (PET) uptake results within 9 months.

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Patients with chronic kidney disease (CKD) experiencing atrial arrhythmia are hypothesized to have elevated CHADS and CHADS-VASc scores, thereby predisposed to left atrial (LA) thrombus formation and subsequent thromboembolism. We examined possible association of LA thrombogenic milieu (TM) with CKD in patients with nonvalvular atrial fibrillation. A total of 581 patients (181 women; mean age, 67 years) who underwent transesophageal echocardiography were examined.

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Several studies have shown that subjects with higher serum bilirubin may have a lower risk of cardiovascular disorders. We herein investigated whether serum bilirubin concentration is associated with lower extremity ischemia among cardiology patients. In total, 935 patients without a history of angioplasty or bypass surgery of the lower limb arteries and who had bilateral ankle-brachial index measurements were included in the study.

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Background: Circulating soluble urokinase-type plasminogen activator receptor (suPAR), which can reflect immune activation and low-grade inflammation, may be a novel biomarker of cardiovascular disease.

Methods: We investigated the potential association between suPAR and the prevalence of atrial fibrillation (AF) by analyzing patients with either sinus rhythm, paroxysmal atrial fibrillation (PAF), or non-paroxysmal atrial fibrillation (NPAF), which indicates either permanent or persistent AF.

Results: Among 426 patients enrolled (mean age 71.

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Immunoglobulin G4 (IgG4)-related disease is an emerging new clinicopathological disorder that is characterized by elevation of serum IgG4 levels and histological findings of IgG4-positive plasmacytic infiltration. IgG4-related disease may appear synchronously or metachronously in a wide variety of organs. The current patient was found to have pericardial effusion and retroperitoneal fibrosis.

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Background: Acute cholecystitis sometimes displays symptoms and electrocardiographic changes mimicking cardiovascular problems. It may also coexist with cardiovascular disorders. We analyzed the clinical characteristic of the cardiac patients who were diagnosed with acute cholecystitis during hospitalization in the cardiology department.

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Ezetimibe is as an inhibitor of NPC1L1 protein, which has a key role in cholesterol absorption. The aim of this study was to evaluate the influence of ezetimibe on the plasma lipid profile, atherosclerotic lesions, and cardiomyocyte ultrastructure in an animal model of atherosclerosis with intermittent hypoxia. Apolipoprotein E-knockout mice received a high-fat diet for 30 days.

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Background: Atrial fibrillation (AF) occurs more frequently among patients with renal dysfunction. We investigated the possible association between prevalence of AF and serum fibroblast growth factor 23 (FGF23), which has been shown to be increased in subjects with renal dysfunction.

Methods And Results: Among the total enrollment of 851 cardiac patients, 188 patients had AF (paroxysmal AF, 95; non-paroxysmal AF, 93).

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We have previously reported that intermittent hypoxic stress, which is relevant to sleep apnea syndrome (SAS), increases oxidative stress and induces left ventricular (LV) remodeling. Celiprolol, a β1-selective adrenoreceptor blocker, is known to have not only an antihypertensive effect but also an antioxidant effect through releasing nitric oxide. The aim of this study was to examine the hypothesis that celiprolol might ameliorate the LV remodeling induced by intermittent hypoxia through its antioxidant effect.

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We herein report the case of a 53-year-old man with severe coronary ischemia who underwent successful coronary artery bypass surgery. Of note, he had hypercholesterolemia and presented with multiple large tendinous xanthomas and thickened Achilles tendons that had been present for more than two decades. Together with a family history of dyslipidemia, the patient was diagnosed as having familial hypercholesterolemia.

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Mutation in the transthyretin (TTR) gene may clinically manifest as cardiomyopathy. Here, we describe 69-year-old and 72-year-old brothers who were diagnosed as having TTR-related familial amyloid cardiomyopathy by endomyocardial biopsy at different hospitals at around the same time. They were not from an endemic area of familial amyloid polyneuropathy.

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Infected aortic aneurysm and inflammatory aortic aneurysm each account for a minor fraction of the total incidence of aortic aneurysm and are associated with periaortic inflammation. Despite the similarity, infected aortic aneurysm generally shows a more rapid change in clinical condition, leading to a fatal outcome; in addition, delayed diagnosis and misuse of corticosteroid or immunosuppressing drugs may lead to uncontrolled growth of microorganisms. Therefore, it is mandatory that detection of aortic aneurysm is followed by accurate differential diagnosis.

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Sleep apnea syndrome increases the risk of cardiovascular morbidity and mortality. We previously reported that intermittent hypoxia increases superoxide production in a manner dependent on nicotinamide adenine dinucleotide phosphate and accelerates adverse left ventricular (LV) remodeling. Recent studies have suggested that hydrogen (H(2)) may have an antioxidant effect by reducing hydroxyl radicals.

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Postprandial hyperglycemia (PPH) and intermittent hypoxia related to the sleep apnea syndrome are important predictors of cardiovascular disease. We investigated the effects of intermittent hypoxia on pathological changes in the left ventricular (LV) myocardium caused by PPH in lean mice and evaluated the influence of acarbose, an α-glucosidase inhibitor. Male C57BL/6J mice aged 8 weeks were exposed to intermittent hypoxia (8 h/day during the daytime) or kept under normoxia.

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We have reported previously that intermittent hypoxia related to sleep apnea induces cardiovascular remodeling secondary to the oxidative stress. The aim of this study was to examine the effect of pitavastatin as an antioxidant to prevent intermittent hypoxia-induced left ventricular (LV) remodeling in mice without hypercholesterolemia. Eight-week-old male C57BL/6J mice (n=35) were exposed to intermittent hypoxia (30 s exposure to 5% oxygen, followed by 30 s exposure to 21% oxygen) for 8 h per day during the daytime or maintained under normoxic conditions; in addition, they were either treated with pitavastatin (3 mg kg(-1) per day) or vehicle for 10 days.

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Aims: Recurrent hypoxia due to sleep apnea syndrome is implicated in cardiovascular events, especially in diabetic patients, but the underlying mechanisms remain controversial. We previously reported that angiotensin II receptor blockers can improve hypoxia-induced left ventricular remodeling. The aim of this study was to examine the effect on left ventricular remodeling of adding a calcium channel blocker to angiotensin II receptor blocker therapy in diabetic mice exposed to recurrent hypoxia.

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