Hiroyuki Ito

Saitama Medical University, Saitama, Saitama-ken, Japan

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Publications (9)9.2 Total impact

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    ABSTRACT: Eicosapentaenoic acid (EPA) has been reported to augment endothelial function and improve clinical outcomes in patients with coronary artery disease (CAD). The purpose of this study was to determine whether EPA could improve residual endothelial dysfunction despite adequate lipid-lowering with statin in CAD patients. Eighty patients with established CAD, who had been on statin treatment and had serum low-density lipoprotein cholesterol (LDL-C) levels <100 mg/dl, were randomly assigned to receive either 1,800 mg of EPA daily plus statin (EPA group, n = 40) or statin alone (Control group, n = 40). Lipid profiles and flow-mediated dilation (FMD) were assessed just before and after more than 3 months of treatment in both groups. Only patients who had impaired FMD (<6 %) before randomization were enrolled. After treatment for 5.2 ± 1.7 months, the EPA group showed a significant increase in the serum concentration of EPA and EPA to arachidonic acid (AA) (EPA/AA) ratio (62.5 ± 38.1 to 159.8 ± 53.8 μg/ml, 0.45 ± 0.34 to 1.20 ± 0.55, p < 0.01 for both). In the EPA group, serum triglycerides significantly decreased (150.7 ± 92.9 to 119.3 ± 60.7 mg/dl, p = 0.02), whereas no significant change was seen in the Control group. FMD, the primary study endpoint, showed a significant improvement in the EPA group (2.6 ± 1.6 % to 3.2 ± 1.6 %, p = 0.02), whereas no significant change was observed in the Control group (2.7 ± 1.6 % to 2.4 ± 1.7 %, p = 0.29). EPA improved endothelial function and impaired FMD in patients with established CAD who were on optimal statin therapy.
    Cardiovascular Drugs and Therapy 10/2013; · 2.67 Impact Factor
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    ABSTRACT: Aortopulmonary artery fistula is uncommon, but the clinical outcome is often lethal. A 76-year-old man with a history of acute thoracic aortic dissection 6 years previously was admitted with dyspnea. A chest x-ray showed pleural effusion and pulmonary congestion. Transthoracic echocardiography revealed preserved systolic function, but continuous and abnormal flow from the distal aortic arch into the pulmonary artery (PA). Transesophageal echocardiography (TEE) in the Doppler color-flow mode demonstrated a left-to-right shunt between a large distal aortic arch aneurysm and the left PA via an aortopulmonary fistula and a pressure gradient across the shunt of 56 mmHg. Contrast-enhanced computed tomography showed that the aneurysm compressed the PA. Aortography also revealed a large distal aortic arch aneurysm and almost simultaneous contrast enhancement of the aorta and the PA. Right-heart catheterization showed a significant increase in oxygen saturation between the right ventricle and the PA. A left-to-right shunt due to a distal aortic arch aneurysm rupturing into the left PA was diagnosed based on these findings. TEE was very helpful in confirming the presence and precise location of the fistula.
    Echocardiography 01/2013; · 1.26 Impact Factor
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    ABSTRACT: How coronary distensibility contributes to stable or unstable clinical manifestations remains obscure. We postulated that the heterogeneous plaque distensibility is associated with unstable clinical presentations in patients with acute coronary syndrome (ACS). Seventeen and 19 ACS-related and -unrelated lesions, respectively, were visualized using intravascular ultrasound imaging with simultaneous intracoronary pressure recording. Systolic and diastolic lumen cross-sectional areas were measured at the lesion site and at five evenly spaced sites between the proximal and distal reference sites. The coronary distensibility index and stiffness index β were calculated for each site and averaged for each coronary segment. Maximal distensibility index, standard deviation and the difference between maximal and minimal distensibility indices within each segment were significantly higher in the ACS-related than -unrelated plaques (5.6 ± 2.3 vs. 3.7 ± 1.8, p < 0.001, 2.1 ± 0.9 vs. 1.1 ± 0.6, p < 0.001 and 5.3 ± 2.3 vs. 2.8 ± 1.5, p < 0.001, respectively). Moreover, the difference in the distensibility index between the lesion site of ACS-related plaques and the immediate proximal site was significantly larger (2.88 ± 2.35 vs. 1.17 ± 1.44, p = 0.022) than that in ACS-unrelated plaques. Coronary artery distensibility is longitudinally more heterogeneous in ACS-related than-unrelated plaques, especially between the lesion and the immediate proximal site.
    Clinical Research in Cardiology 02/2012; 101(7):545-51. · 3.67 Impact Factor
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    ABSTRACT: The slurries-containing tetra-n-butyl ammonium bromide (TBAB) solution and its semiclathrate hydrate have attracted a lot of interest as latent heat transport media. These hydrate slurries contain some microparticles of crystal, and the size and shape of these hydrate particles could affect the mobility of slurries. Hence, it is essential to investigate the efficient hydrate-slurry preparation methods and the effect of hydrate particles on the fluid property of slurries for the application to latent heat transport media. In the present study, the effect of agitation on particle size distribution and aggregation of particles was studied to prepare easily flowing TBAB hydrate slurries that were suitable for fluid transport. First of all, the effects of impeller rotational speed and impeller type on the particle size and frequency of aggregation were investigated. The results suggested that the particle size distribution and the frequency of particle aggregation are strongly affected by the intensity of shear rate and its uniformity, which was controllable with impeller type and its rotation speed.
    International Journal of Chemical Engineering 01/2012; 2012.
  • KAGAKU KOGAKU RONBUNSHU 01/2010; 36(1):1-16. · 0.37 Impact Factor
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    ABSTRACT: Isolated mixing region in agitated vessel with rotated two-bladed paddle impeller and no baffle was visualized experimentally and its structural property was investigated in detail. A set of thin filaments spirally wrapping around the core of the toroidal isolated mixing region is observed under low Reynolds number conditions, which is smaller than 60. Three-dimensional geometrical structure of filament in isolated mixing region depends on the periodical perturbations caused by the rotating impeller. We have succeeded in the determination of three-dimensional geometrical structure of filament in isolated mixing region based on relation between the movement of fluid particle and filament numbers and/or wire turns. Interestingly, the wire turns of filaments are opposite to movements of fluid particles.
    Chemical Engineering Science - CHEM ENG SCI. 01/2009; 64(24):5173-5181.
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    ABSTRACT: Preventing left ventricular (LV) remodeling after coronary artery bypass graft surgery (CABG) is important to avoid long-term congestive heart failure. The present study evaluated the effects of angiotensin converting enzyme inhibitors (ACEIs) and beta-blockers on LV remodeling. Twenty-three patients with angina pectoris and 36 with old myocardial infarction underwent CABG. We assessed end diastolic volume index (EDVI), end systolic volume index (ESVI), and ejection fraction (EF) using left ventriculography before and after CABG. Changes in EDVI, ESVI, and EF were studied in the ACEI, beta-blocker, and control groups. Although EDVI was reduced in the ACEI group, ESVI and EF improved only slightly, whereas in the group given beta-blockers, ESVI was reduced, EF improved, and EDVI was minimally reduced. These results indicate that ACEIs and beta-blockers both protect against LV remodeling, although through different mechanisms.
    International Heart Journal 08/2008; 49(4):385-90. · 1.23 Impact Factor
  • International Heart Journal - INT HEART J. 01/2008; 49(4):385-390.
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    ABSTRACT: Recently, slurries with phase change materials (hereafter, PCM) having latent heat have been received much attention as a high-density heat transportation system. So far, it has been reported that the thermal ability of slurries containing tetra-n-butyl ammonium salt solutions and their semi-clathrate hydrate: tetra-n-butyl ammonium bromide (TBAB) and fluoride (TBAF) as latent heat transport media is favorable. In the present study, the viscosity characteristics of TBAB or TBAF solutions and their hydrate-slurries were measured at various concentrations of solutions by use of a stress-control-type rheometer with parallel-plate device. The apparent viscosity of both solution and hydrate slurries increases as the temperature decreases, which may be caused by the increase of solid (hydrate particle) fraction in solution. The hydrate slurries exhibit the behavior like pseudo-plastic fluid. The viscosity characteristics of these hydrate slurries can be treated by use of only solid fraction despite different unit-cell structure between TBAB and TBAF hydrates. In addition, a very small amount of surfactant drastically reduces the apparent viscosity of hydrate slurries, which may be caused by the electric repulsion of surfactant-adsorbed hydrate particles. NOMENCLATURE C: concentration [wt%] H f : hydrate fraction in slurries [-] m, n: arbitrary real number [-] T: temperature [K] !: shear rate [s -1 ] ": apparent viscosity [Pa • s] #: shear stress [Pa] INTRODUCTION Gas hydrates are one of clathrate inclusion compounds, which are stabilized by guest species in the cavity of cages. These hydrate cages are composed of the hydrogen-bonded water molecules. The hydrate structure mainly depends on the size and shape of enclathrated guest species.

Publication Stats

4 Citations
9.20 Total Impact Points

Institutions

  • 2008–2013
    • Saitama Medical University
      • Saitama Medical Center
      Saitama, Saitama-ken, Japan
  • 2009–2012
    • Osaka University
      • Graduate School of Engineering Sciences
      Suika, Ōsaka, Japan