Hiroshi Ito

Okayama University, Okayama, Okayama, Japan

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Publications (639)2673.5 Total impact

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    ABSTRACT: We report the room-temperature and low-temperature transport properties of a poly(2,5-bis(3-hexadecylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT) film gated with an ionic liquid based on 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide at different annealing temperatures of the PBTTT film. By annealing the film up to 235 °C and subsequently cooling it, we observed a ribbonlike structure, as reported. For the 235-°C-annealed (ribbon phase) film, we could apply a higher voltage without any decrease in the channel conductivity than for the 180-°C-annealed (terrace phase) film. As a result, a charge mobility as high as 10 cm2 V−1 s−1 was achieved for the ribbon-phase film. The power-law behavior of the temperature dependence of the electrical conductivity at low temperatures, indicating the critical regime for the insulator–metal transition, was observed. The ribbon-phase film exhibits an even weaker temperature dependence with a smaller exponent of β = 0.10 than the terrace-phase film.
    No preview · Article · Mar 2016 · Japanese Journal of Applied Physics
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    ABSTRACT: Epicardial adipose tissue (EAT) volume is reported to be associated with coronary plaques. We evaluated whether non-invasive measurement of EAT thickness by echocardiography can predict high-risk coronary plaque characteristics determined independently by coronary computed tomography (CT) angiography. We enrolled 406 patients (mean age 63 years, 57 % male) referred for 64-slice CT. EAT was measured on the right ventricle free wall from a parasternal long-axis view at the end of systole. High-risk coronary plaques were defined as low-density plaques (<30 Hounsfield units) with positive remodeling (remodeling index >1.05). Patients were divided into thin or thick EAT groups using a cutoff value derived from receiver operator characteristic curve analysis for discriminating high-risk plaques. The receiver operator characteristic cutoff value was 5.8 mm with a sensitivity of 83 % and specificity of 64 % (area under the curve 0.77, 95 % confidence interval 0.70–0.83, p < 0.01). Compared with the thin EAT group, the thick EAT group had a high prevalence of low-density plaques (4 vs. 24 %, p < 0.01), positive remodeling (39 vs. 60 %, p < 0.01), and high-risk plaques (3 vs. 17 %, p < 0.01). Multiple logistic analysis revealed that thick EAT was a significant predictor of high-risk plaques (odds ratio 7.98, 95 % confidence interval 2.77–22.98, p < 0.01) after adjustment for covariates, including conventional risk factors, visceral adipose tissue area, and medications. The measurement of EAT thickness by echocardiography may provide a non-invasive option for predicting high-risk coronary plaques.
    No preview · Article · Feb 2016 · Heart and Vessels
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    ABSTRACT: Nanoparticles (NPs) have been used as a novel drug delivery system. Drug-incorporated NPs for local delivery might optimize the efficacy and minimize the side effects of drugs. Intravenous prostacyclin improves long-term survival in patients with pulmonary arterial hypertension (PAH), but it causes serious side effects such as catheter-related infections. We investigated the efficacy and safety of intratracheal administration of prostacyclin analog (beraprost)-incorporated NPs (BPS-NPs) in Sugen-hypoxia-normoxia and monocrotaline (MCT) rat models of PAH and in human PAH-pulmonary arterial smooth muscle cells (PASMCs). After a single administration, BPS-NPs significantly decreased right ventricular pressure, right ventricular hypertrophy and pulmonary artery muscularization in the both rat models. BPS-NPs significantly improved survival rate in the MCT rat model. No infiltration of inflammatory cells, hemorrhage or fibrosis was found in the liver, kidney, spleen and heart after administration of BPS-NPs. No liver or kidney dysfunction was found in blood examinations. BPS and BPS-NPs significantly inhibited proliferation of human PAH-PASMCs after 24 hours of treatment. BPS-NPs significantly continued to inhibit proliferation of human PAH-PASMCs at 24 hours after removal of BPS-NPs. BPS-NPs significantly induced apoptosis in PAH-PASMCs compared with that in non PAH-PASMCs. Intratracheal administration of BPS-NPs ameliorates pulmonary hypertension in PAH rat models by a sustained antiproliferative effect and pro-apoptotic effect on PAH-PASMCs.This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND), which permits downloading and sharing the work provided it is properly cited. The work cannot be changed in any way or used commercially.
    No preview · Article · Jan 2016 · Journal of Cardiovascular Pharmacology

  • No preview · Article · Jan 2016 · Circulation
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    ABSTRACT: Some types of migraine are associated with ischemic stroke. Although a right-to-left communication is linked with ischemic stroke, a causal relationship between migraine and right-to-left communication remains unclear. Furthermore, the efficacy of transcatheter closure of atrial communication on migraine is controversial. We aimed to evaluate the influence of transcatheter closure of atrial communication on migraine in patients with ischemic stroke. Thirty-eight consecutive patients with ischemic stroke who underwent transcatheter closure of atrial communication were enrolled. The prevalence, frequency, and severity of migraine were prospectively evaluated at baseline, 3 months, and >6 months after the procedure. Changes in migraine after the procedure were classified according to the frequency and severity of migraine: disappeared, improved, no-change, and worsening. Nineteen (50 %) of 38 patients suffered from migraine at baseline. No significant differences were observed in age, comorbidities, defect diameter, and atrial septal aneurysm between patients with migraine and patients without migraine. Among the 19 patients with migraine, migraine disappeared in 10 (53 %) patients and improved in 8 (42 %) patients at 3 months after transcatheter closure of atrial communication. At mean follow-up of 38 ± 28 months after the procedure, migraine disappeared in 12 (63 %) patients and improved in five (26 %) patients. No patients experienced worsening of migraine during the follow-up period. New-onset migraine was not observed in patients without migraine. Migraine is complicated in a half of patients with ischemic stroke related to atrial communication. Such migraine may disappear or improve after transcatheter closure of atrial communication.
    No preview · Article · Dec 2015 · Cardiovascular Intervention and Therapeutics
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    ABSTRACT: We obtained a new cation radical salt of bis(ethylenedithio) tetrathiafulvalene (ET) with kappa-type packing motif, kappa-(ET)(2)Ag(CN)[N(CN)(2)], by electrooxidation. In the salt, each ET layer is separated by polymeric {Ag(CN)[N(CN)(2)](-)}(infinity) layers, which are composed of Ag(I) ions trigonally coordinated to form an infinite zigzag chain of -NC-Ag-NC-Ag with pendant dicyanamides. The salt undergoes a superconducting transition with a midpoint critical temperature (T-c) of 6.6K and an onset T-c of 7.2 K, thereby indicating the highest T-c among ET superconductors formed with a polymeric Ag(I) complex anion.
    No preview · Article · Dec 2015 · Journal of the Physical Society of Japan
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    ABSTRACT: Electronic state of charge carriers, in particular, in highly doped regions, in thin-film transistors of a semicrystalline conducting polymer poly(2,5-bis(3-alkylthiophene-2-yl) thieno[3,2-b] thiophene), has been studied by using field-induced electron spin resonance (ESR) spectroscopy. By adopting an ionic-liquid gate insulator, a gate-controlled reversible electrochemical hole-doping of the polymer backbone is achieved, as confirmed from the change of the optical absorption spectra. The edge-on molecular orientation in the pristine film is maintained even after the electrochemical doping, which is clarified from the angular dependence of the g value. As the doping level increases, spin 1/2 polarons transform into spinless bipolarons, which is demonstrated from the spin-charge relation showing a spin concentration peak around 1%, contrasting to the monotonic increase in the charge concentration. At high doping levels, a drastic change in the linewidth anisotropy due to the generation of conduction electrons is observed, indicating the onset of metallic state, which is also supported by the temperature dependence of the spin susceptibility and the ESR linewidth. Our results suggest that semicrystalline conducting polymers become metallic with retaining their molecular orientational order, when appropriate doping methods are chosen. (C) 2015 AIP Publishing LLC.
    No preview · Article · Dec 2015 · Applied Physics Letters
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    ABSTRACT: Statin therapy targeting reduction of low-density lipoprotein cholesterol (LDL-C) decreases the risk of coronary heart disease (CHD) and all-cause mortality. However, a substantial number of cases of CHD are not prevented and residual risk factors remain unsettled. A high triglyceride (TG) level is considered to be an important and residual risk factor. Postprandial hyperlipidemia is a condition in which TG-rich chylomicron remnants are increased during the postprandial period and hypertriglycedemia is protracted. Postprandial hyperlipidemia evokes atherogenesis during the postprandial period. Several prospective studies have revealed that nonfasting serum TG levels predict the incidence of CHD. Values of TG, remnant lipoprotein cholesterol, and remnant lipoprotein TG after fat loading were significantly higher in diabetes patients with insulin resistance than in diabetes patients without insulin resistance. Endothelial dysfunction is an initial process of atherogenesis and it contributes to the pathogenesis of CHD. Postprandial hyperlipidemia (postprandial hypertriglyceridemia) is involved in the production of proinflammatory cytokines, recruitment of neutrophils, and generation of oxidative stress, resulting in endothelial dysfunction in healthy subjects, hypertriglyceridemic patients, or type 2 diabetic patients. Effective treatment has not been established till date. Ezetimibe or omega-3 fatty acids significantly decrease postprandial TG elevation and postprandial endothelial dysfunction. Ezetimibe or omega-3 fatty acids added to statin therapy reduce serum TG levels and result in good outcomes in patients with CHD. In conclusion, postprandial hyperlipidemia is an important and residual risk factor especially in patients with insulin resistance syndrome (metabolic syndrome) and diabetes mellitus. Further studies are needed to establish effective treatment.
    No preview · Article · Dec 2015 · Journal of Cardiology
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    Takashi Koyama · Hiroyuki Watanabe · Hiroshi Ito

    Full-text · Article · Nov 2015 · Circulation Journal
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    ABSTRACT: Background: A therapeutic strategy in patients with atrial septal defect (ASD) and significant pulmonary arterial hypertension (PAH) remains controversial. This study aimed to assess the effect of PAH-specific medications and subsequent transcatheter shunt closure (ie, a treat and repair strategy) in these patients.Methods and Results:Among 646 patients with ASD, 22 patients (mean age of 56±20 years) who had PAH [mean pulmonary artery pressure ≥25 mmHg and pulmonary vascular resistance (PVR) ≥3 Wood units] underwent successful transcatheter ASD closure. Prior to the procedure, 8 patients received PAH-specific medications (PHM group) and 14 patients did not (non-PHM group). Initially, the PHM group had higher PVR compared with non-PHM group (9.6±3.8 vs. 4.2±1.0 Wood units, P<0.01). After treatment with PAH-specific medications, PVR in this group decreased to 4.0±0.8 Wood units (P<0.01). No adverse events were observed in either the PHM or non-PHM group during or after the transcatheter procedure. In the PHM group, during a treatment period of 52±48 months, the World Health Organization Functional Classification significantly improved (3.0±0.5 to 2.0±0.0, P<0.01), as well as in the non-PHM group (2.1±0.6 to 1.5±0.5, P<0.01). Conclusions: Treat and repair strategy provided substantial improvement and no worsening of the WHO-FC, even in patients with ASD and significant PAH. Long-term hemodynamic follow-up is mandatory to evaluate the ultimate efficacy and safety of this new strategy.
    Full-text · Article · Nov 2015 · Circulation Journal
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    ABSTRACT: Objective Hepatopulmonary syndrome (HPS) is characterized by vascular dilatation and hyperdynamic circulation, while portopulmonary hypertension (POPH) is characterized by vasoconstriction with fibrous obliteration of the vascular bed. Vasoactive molecules such as nitric oxide (NO) are candidate factors for cirrhotic complications associated with these diseases. However, oxidative stress balance is not well characterized in HPS and POPH. The present objective is to investigate the oxidative stress and anti-oxidative stress balance and NO pathway balance in patients with potential HPS and POPH. Methods We recruited patients with decompensated cirrhosis (n=69) admitted to our hospital as liver transplantation candidates. Patients exhibiting partial pressure of oxygen lower than 80 mmHg and alveolararterial oxygen gradient (AaDO2) ≥15 mmHg were categorized as potentially having HPS (23 of 69 patients). Patients exhibiting a tricuspid regurgitation pressure gradient ≥25 mmHg were categorized as potentially having POPH (29 of 61 patients). Serum reactive oxygen metabolites were measured and anti-oxidative OXYadsorbent test (OXY) were performed, and the balance of these tests was defined as the oxidative index. The correlation between these values and the clinical characteristics of the patients were assessed in a crosssectional study. Results Potential HPS patients exhibited no correlation with oxidative stress markers. Potential POPH patients exhibited lower OXY (p=0.037) and higher oxidative index values (p=0.001). Additionally, the vascular NO synthase enzyme inhibiting protein, asymmetric dimethylarginine, was higher in potential POPH patients (p=0.049). The potential POPH patients exhibited elevated AaDO2, suggesting the presence of pulmonary shunting. Conclusion Potential POPH patients exhibited elevated oxidative stress with decreased anti-oxidative function accompanied by inhibited NO production. Anti-oxidants represent a candidate treatment for potential POPH patients.
    Full-text · Article · Nov 2015 · Internal Medicine
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    ABSTRACT: Two novel antiperovskite charge-transfer (CT) solids composed of a tetraselenafulvalene radical cation (TSF˙+), a dianionic molybdenum cluster unit [Mo6X14]2−, and a halogen anion (Y−) (X, Y = Cl, Br) were prepared by electrocrystallization. Their crystal structures and magnetic properties with regard to spin frustration are discussed together with those of isostructural tetrathiafulvalene (TTF) CT solids previously reported. Both TSF and TTF salts have an apex sharing distorted octahedral spin lattice with a rhombohedral R space group. The calculated overlap integrals based on the crystal structures and insulating nature of the TSF salts indicate that they are Mott insulators. Their spin susceptibilities obeyed the Curie–Weiss law and exhibited an antiferromagnetic ordering at lower temperatures for the TSF salts (Néel temperature, TN = 3.0 K for X = Y = Cl and 5.5 K for X = Y = Br) than the TTF salts. The Curie–Weiss temperatures (\textbarΘCW\textbar ∼ 1.6–6.3 K) for the TSF salts are lower than those of the TTF salts. For the TSF salts, spin-flop behavior was detected at 3.2 T for X = Y = Cl and 1.5 T for X = Y = Br at 1.9 K. Due to both the distortion of the octahedral geometry of the spin lattice and the anisotropic molecular orientation, the geometrical spin frustrations in TSF and TTF systems are weakened
    Full-text · Article · Oct 2015 · Journal of Materials Chemistry C
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    ABSTRACT: Background: Brugada syndrome (BrS)-type electrocardiogram (ECG) is concealed by complete right bundle-branch block (CRBBB) in some cases of BrS. Clinical significance of BrS masked by CRBBB is not well known.Methods and Results:We reviewed an ECG database of 326 BrS patients who had type 1 ECG with or without pilsicainide. "BrS masked by CRBBB" was defined on ECG as <2-mm elevation of the J point at the time of CRBBB in the right precordial leads, and BrS-type J-point elevation ≥2 mm at the time of normalized QRS complex on relieved CRBBB. We identified 25 BrS patients (7.7%) with persistent (n=12) or intermittent CRBBB (n=13). Relief of CRBBB by pacing was performed in patients with persistent CRBBB. The prevalence of BrS masked by CRBBB was 3.1% (10/326 patients). Three patients had type 1 ECG, and 7 patients had type 2 or 3 ECG on relief of CRBBB. Two of these 10 patients had lethal arrhythmic events during the follow-up period (mean, 86.4±57.2 months). There was no prognostic difference between BrS masked by CRBBB and other BrS. Conclusions: In a small BrS population, CRBBB can completely mask typical BrS-type ECG. BrS masked by CRBBB is associated with the same risk of fatal ventricular tachyarrhythmia as other BrS.
    Full-text · Article · Oct 2015 · Circulation Journal
  • Shin Makabe · Hiroyuki Watanabe · Hiroshi Ito

    No preview · Article · Oct 2015

  • No preview · Article · Oct 2015 · Journal of the American College of Cardiology
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    ABSTRACT: Infective endocarditis (IE) associated with atrial septal defect (ASD) is extremely rare. However, tricuspid regurgitation (TR) secondary to right ventricular overload is a potential cause of IE, and once it occurs, the development of a paradoxical embolism may lead to fatal complications. We herein report the case of a 50-year-old woman who was admitted due to a persistent fever resistant to antibiotics. Echocardiography showed secundum ASD, moderate TR and a mobile vegetation measuring 15x10 mm attached to the tricuspid valve. Given the risk of developing a paradoxical embolism, urgent surgery was successfully performed.
    Full-text · Article · Oct 2015 · Internal Medicine

  • No preview · Article · Oct 2015

  • No preview · Article · Oct 2015 · Journal of Cardiac Failure

  • No preview · Article · Oct 2015 · Journal of Cardiac Failure
  • Takashi Koyama · Hiroyuki Watanabe · Hiroshi Ito

    No preview · Article · Oct 2015 · Journal of Cardiac Failure

Publication Stats

10k Citations
2,673.50 Total Impact Points

Institutions

  • 2009-2015
    • Okayama University
      • Department of Cardiovascular Medicine
      Okayama, Okayama, Japan
  • 2005-2015
    • Akita University
      • Department of Cardiovascular and Respiratory Medicine
      Akita, Akita, Japan
  • 2004-2015
    • Nagoya University
      • • Department of Molecular Design and Engineering
      • • Graduate School of Engineering
      • • Research Center for Materials Science
      • • Department of Micro-Nano Systems Engineering
      Nagoya, Aichi, Japan
  • 1991-2015
    • Kyoto University
      • Department of Physics II
      Kioto, Kyoto, Japan
  • 2014
    • Osaka City University
      • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan
  • 2011-2014
    • Fukaya Red Cross Hospital
      Fukaya, Saitama, Japan
    • Yokohama Ekisaikai Hospital
      Yokohama, Kanagawa, Japan
  • 2006-2012
    • Akita University Hospital
      Akita, Akita, Japan
  • 1992-2011
    • Sakurabashi Watanabe Hospital
      Ōsaka, Ōsaka, Japan
  • 2008
    • Juntendo University
      Edo, Tōkyō, Japan
  • 1997-2008
    • Chiba University
      • • Department of Oral Surgery
      • • Graduate School of Medicine
      Tiba, Chiba, Japan
  • 1995-2008
    • Yamaguchi University
      • • Department of Medical Bioregulation
      • • Yamaguchi University Hospital
      Yamaguti, Yamaguchi, Japan
    • Himeji Institute of Technology
      • Department of Material Science
      Himezi, Hyōgo, Japan
  • 2004-2006
    • Massachusetts General Hospital
      • Transplantation Biology Research Center
      Boston, MA, United States
  • 2003
    • University Hospital Medical Information Network
      Edo, Tōkyō, Japan
    • Musashino Red Cross Hospital
      Edo, Tōkyō, Japan
  • 1988-2002
    • Tokyo Medical and Dental University
      • • Department of Cardiovascular Medicine
      • • Department of Internal Medicine
      • • Department of Medicine
      Edo, Tōkyō, Japan
  • 1998-2001
    • Chiba University Hospital
      Tiba, Chiba, Japan