S Ogawa

Keio University, Edo, Tōkyō, Japan

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Publications (204)629.23 Total impact

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    ABSTRACT: We have demonstrated photosensitization reaction-induced electrical conduction block of myocardial tissue. Subcellular distribution of photosensitizer and electrophysiological cell response to this photosensitization reaction were studied with rat myocardial cells, in order to clarify the mechanism of the myocardial electrical conduction block with photodynamic therapy (PDT). Photofrin® was used as photo sensitizer in this study. The subcellular distribution of the photosensitizer was obtained by microscopic fluorescent observation. The sites of photosensitizer localization were deter mined by organelle fluorescent probe, Rhodamine® 123, to specify the mitochondria location. The myocardial cell response to the photosensitization reaction was studied by the observation of intracellular Ca2 +  dynamics. Intracellular free Ca2 + concentration in the myocardial cells was measured with fluorescent Ca2 +  indicator, Fluo-4 AM, by a high-speed Nipkow type confocal laser microscope during the PDT when the photosensitizer was distributed outside the cells or localized to intracellular compartments. We concluded that the Ca2 +  influx accompanied by cell membrane damage when the photosensitizer was distributed outside the cells or on the cell membrane was the possible mechanism of the myocardial electrical conduction block with the photosensitization reaction. KeywordsPhotodynamic therapy-photosensitization reaction-Photofrin®-electrical conduction block-Ca2 + 
    01/2010: pages 229-231;
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    ABSTRACT: Infertility patients are known to be at increased risk of endometrial carcinoma (EC) and atypical hyperplasia (AH). However, the incidence and clinical features of EC and AH in these patients remain to be clarified. In this study, we examined the rate at which a routine infertility workup revealed EC/AH and investigated the clinicopathological features of EC/AH detected in this way. Among patients diagnosed with EC or AH at the Jichi Medical University Hospital between the 10-year period from 1997 to 2006, six patients were referred from Tochigi Central Clinic, a specialized infertility facility. We report the clinicopathological features of these patients and calculate the incidence of EC/AH in patients who underwent infertility investigations at Tochigi Central Clinic. All six patients were younger than 40 and had early stage disease (final diagnosis: EC stage IA: 3, EC stage IB: 1, AH: 2). A total of 19 826 patients underwent routine infertility investigations at Tochigi Central Clinic during the same period. The incidence of EC/AH detected from these investigations was 0.03% (6/19 826) and that of EC was 0.02% (4/19 826): 5-10 times higher than the overall incidence in Japanese women of the same age. Routine infertility investigations may provide an opportunity to examine the corpus uteri of young women in whom examination is otherwise limited, contributing to the early detection of EC/AH.
    Human Reproduction 03/2009; 24(5):1045-50. · 4.67 Impact Factor
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    ABSTRACT: We have proposed a new type of atrial fibrillation treatment with the early state photodynamic therapy (PDT), in which the interval time between the photosensitizer injection and irradiation is shorter than that in conventional way. We had demonstrated the acute electrical blockade by the PDT with talaporfin sodium and a red (670 nm) diode laser in ex vivo and in vivo experiment using rat normal myocardial tissue. The previous study of intracellular Ca2+ concentration measurement in rat cardiac myocytes during the PDT indicated that Ca2+ influx induced by the plasma membrane damage might be the main cause of the acute reaction of myocardial tissue. We found that the cell damage of cardiac myocytes triggered by the PDT was mainly influenced by the site where the photosensitizer exists. In this study, we examined the relationship between the sites of talaporfin sodium existing and cell death phenotypes in response to the PDT, in order to clarify the mechanism of the acute electrical blockade induced by the PDT in myocardial tissue. The talaporfin sodium fluorescence was observed after the various incubation times to visualize the time-lapse intracellular photosensitizer localization. The distribution of the photosensitizer was dependent on the incubation time. The change in intracellular Ca2+ concentration during the PDT was examined with a fluorescent Ca2+ indicator by a high-speed Nipkow confocal laser microscope (CSU-X1, Yokogawa Electric Company). We obtained the Ca2+ dynamics during the PDT which can explain the PDT-induced cell death pathways. We concluded that the Ca2+ influx induced by plasma membrane damage is the possible mechanism of the electrical blockade by the early state PDT.© (2009) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
    02/2009;
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    ABSTRACT: We have proposed a new type of atrial fibrillation treatment with the early state photodynamic therapy (PDT), in which the interval time between the photosensitizer injection and irradiation is shorter than that in conventional way. We had demonstrated the acute electrical blockade by the PDT with talaporfin sodium and a red (670 nm) diode laser in ex vivo and in vivo experiment using rat normal myocardial tissue. The previous study of intracellular Ca2+ concentration measurement in rat cardiac myocytes during the PDT indicated that Ca2+ influx induced by the plasma membrane damage might be the main cause of the acute reaction of myocardial tissue. We found that the cell damage of cardiac myocytes triggered by the PDT was mainly influenced by the site where the photosensitizer exists. In this study, we examined the relationship between the sites of talaporfin sodium existing and cell death phenotypes in response to the PDT, in order to clarify the mechanism of the acute electrical blockade induced by the PDT in myocardial tissue. The talaporfin sodium fluorescence was observed after the various incubation times to visualize the time-lapse intracellular photosensitizer localization. The distribution of the photosensitizer was dependent on the incubation time. The change in intracellular Ca2+ concentration during the PDT was examined with a fluorescent Ca2+ indicator by a high-speed Nipkow confocal laser microscope (CSU-X1, Yokogawa Electric Company). We obtained the Ca2+ dynamics during the PDT which can explain the PDT-induced cell death pathways. We concluded that the Ca2+ influx induced by plasma membrane damage is the possible mechanism of the electrical blockade by the early state PDT.
    Proc SPIE 02/2009;
  • European Journal of Heart Failure Supplements 06/2005; 4(S1).
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    ABSTRACT: Dopamine treatment constitutes a major advance towards the management of severe ovarian hyperstimulation syndrome (OHSS) by causing renal and mesenteric vasodilatation as well as diuretic and positive inotropic actions. Docarpamine, an oral dopamine prodrug, is converted into dopamine after enteral administration, and the generated dopamine causes renal vasodilatation and diuresis. The purpose of this study was to assess whether docarpamine had beneficial effects in patients with OHSS. Twenty-seven patients, hospitalized because of OHSS and refractory to the initial therapy with intravenous albumin, were treated by docarpamine, after informed consent had been obtained. A 750-mg tablet of docarpamine was taken every 8 h. In some cases, the plasma levels of free dopamine were measured. The daily urinary outputs before and 1, 2, 3 and 4 days after the docarpamine treatment were 839 +/- 424 ml, 1121 +/- 608 ml, 1168 +/- 504 ml, 1325 +/- 815 ml and 1133 +/- 509 ml, respectively. There were significant differences between the first and each of the others (p < 0.05). In 19 (86.4%) of 22 patients treated, clinical symptoms associated with ascites were gradually improved after administrating docarpamine. The plasma free dopamine concentration rose to as high as 55.9 +/- 33.2 mg/ml during the first hour, which corresponded to the usual intravenous drip infusion treatment with dopamine. Moreover, there were no major adverse effects of docarpamine in this study. This was the first demonstration of docarpamine treatment in patients with intravenous albumin-resistant OHSS. Although no effect was seen in pregnant women, diuresis was increased in some women, and ascites decreased. These findings indicate that oral docarpamine administration could be one of the options in the management of patients with OHSS using dopamine therapy.
    Gynecological Endocrinology 08/2003; 17(4):281-6. · 1.30 Impact Factor
  • Circulation Journal. 01/2003; 67:738-741.
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    ABSTRACT: Clinical experience suggests that sodium channel blockers are effective in converting atrial fibrillation of recent onset but not chronic atrial fibrillation. We investigated changes in the electrophysiologic effects of pilsicainide, a pure sodium channel blocker, on the canine atrium during chronic rapid pacing (400/min). Three pairs of bipolar electrodes were sutured to the right atrial appendage in six dogs. Five days later, rapid atrial pacing was started after baseline measurements of the effective refractory period (ERP), the intra-atrial conduction velocity, the atrial wavelength, and the inducibility of atrial fibrillation. These studies were repeated at 2, 7, and 14 days of pacing, both before and after pilsicainide administration. Before pacing, pilsicainide increased ERP more than it decreased conduction velocity, causing an increase of wavelength, particularly at faster rates. However, this use-dependent prolongation of ERP disappeared after 2 days of pacing. Thus, pilsicainide failed to prolong ERP during chronic pacing, allowing progressive shortening of wavelength in the remodeled atrium. The effect of sodium channel blockers on atrial refractoriness may decline as rapid atrial excitation persists, limiting the usefulness of these agents for the treatment of chronic atrial fibrillation.
    Journal of Cardiovascular Pharmacology 01/2002; 38(6):812-20. · 2.38 Impact Factor
  • Journal of Cardiovascular Electrophysiology 11/2001; 12(10):1202. · 3.48 Impact Factor
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    ABSTRACT: Increased neurohormone and cytokine concentrations are associated with adverse outcome in patients with congestive heart failure, so minimizing these increases may improve outcome, even in the acute phase of decompensated heart failure. The present study was designed to test the hypothesis that phosphodiesterase inhibitors, but not catecholamines, could favorably affect neurohormone and cytokine profiles in patients with acutely decompensated heart failure. Twenty-nine patients underwent monitoring using a Swan-Ganz catheter and were randomly allocated to receive phosphodiesterase inhibitors (PDEI group, n=19) or catecholamines (CA group, n=10). Pulmonary capillary wedge pressure decreased significantly in both groups and cardiac output showed a slight, but not statistically significant increase, in both groups. There was a significant decrease in plasma brain natriuretic peptide concentration in the PDEI group, but not in the CA group, whereas plasma interleukin-6 concentration increased in the CA group, but not in the PDEI group. Phosphodiesterase inhibitors favorably affect neurohormone and cytokine concentrations in patients with acutely decompensated heart failure.
    Japanese Circulation Journal 11/2001; 65(10):858-62.
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    ABSTRACT: A newly developed critical pathway has been applied to emergency medical care of patients with acute myocardial infarction (AMI) in the emergency department. The arrival-in-cath-lab interval (ACI) was selected as a clinical indicator of quality assurance, according to American Heart Association and American College of Cardiology guidelines. This report describes the first experience of applying the critical pathway to patients with AMI in an emergency department in Japan. The ACI of 35 AMI patients who underwent primary percutaneous transluminal coronary angioplasty during a 24-month period following application of the pathway were compared with those of 50 AMI patients during the 48 months before application of the pathway. The median ACI value was significantly reduced from 65.5 min to 50.0 min. Also, the proportion of patients with acceptably short ACI (<60 min) significantly improved from 42.0% to 68.6%.
    Japanese Circulation Journal 11/2001; 65(10):849-52.
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    ABSTRACT: Few previous reports have comprehensively screened all the anti-myocardial autoantibodies (AMCA) in relation to other clinical profiles in patients with idiopathic dilated cardiomyopathy (IDC), so the present study used both immunohistochemistry (FITC) and immunoblotting (IB) for screening patients with IDC in order to characterize the clinical significance of AMCA. Sera were collected from 100 patients with IDC and age-matched 100 healthy control subjects (CTL). For FITC, an unfixed frozen section of human myocardium was used for the standard indirect immunofluorescence; for IB, total cardiac homogenates of the same myocardium were blotted to serum at 2 sets of dilution (1:200 and 1:10,000). The positive rates of AMCA detection for each method were as follows (IDC vs CTL); 39% vs 6% for FITC, 38% vs 4% for IB (1:200), and 10% vs 0% for IB (1:10,000). Fifty-nine patients with IDC and 8 CTL were positive for AMCA by either method, and 18 patients with IDC and 2 CTL were positive for AMCA by both methods. IB-positivity at 1:200 was an independent predictor by multiple logistic regression analysis of non-sustained ventricular tachycardias as well as left ventricular end-diastolic diameter and plasma norepinephrine concentration.
    Japanese Circulation Journal 11/2001; 65(10):867-73.
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    ABSTRACT: We report a case of Wolff-Parkinson-White syndrome coexistent with atresia of the coronary sinus (CS) ostium and persistence of the left superior vena cava. The accessory pathway was located at the blind end of the CS, which was bumped with mechanical loss of preexcitation during mapping by a catheter from within the CS. The accessory pathway was successfully ablated with radiofrequency energy applied to this site from the right atrium. This unique combination of anatomically matched anomalies may be important in suggesting a potential embryologic link between the accessory pathway and the coronary vein.
    Journal of Cardiovascular Electrophysiology 10/2001; 12(9):1080-2. · 3.48 Impact Factor
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    ABSTRACT: We investigated the recovery of electrophysiological parameters from electrical remodeling after conversion of chronic lone atrial fibrillation in humans. Clinical studies have shown that the longer atrial fibrillation lasts, the more difficult it becomes to maintain the sinus rhythm after cardioversion. To explore the effects of the duration of atrial fibrillation on changes of electrophysiological parameters after conversion, we determined the atrial effective refractory period and P wave duration during right atrial pacing at 1 and 24 h after electrical cardioversion in 15 patients with chronic lone atrial fibrillation (median duration, 6 months). By 24 h after cardioversion, the effective refractory period at a pacing cycle length of 600 ms increased from 225+/-19 to 254+/-27 ms. However, the P wave duration did not decrease significantly 24 h after conversion. As the duration of atrial fibrillation became longer, the prolongation of effective refractory period was more delayed (P<0. 001, r=0.82), and the shortening of P wave duration was significantly smaller within 24 h after cardioversion (P<0. 001, r=0.67). After cardioversion of chronic lone atrial fibrillation, the recovery of shortened atrial refractoriness and prolonged intraatrial conduction time is dependent on the duration of preexisting atrial fibrillation.
    International Journal of Cardiology 08/2001; 79(2-3):183-9. · 6.18 Impact Factor
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    ABSTRACT: A 62 year old man was admitted for evaluation of recurrent episodes of syncope. A surface ECG showed frequent repetitive premature ventricular complexes of right ventricular outflow tract origin. Ventricular fibrillation was inducible by programmed electrical stimulation but otherwise cardiac evaluation was unremarkable. A diagnosis of idiopathic ventricular fibrillation was made and an implantable cardioverter-defibrillator (ICD) was installed. However, spontaneous ventricular fibrillation recurred, requiring repeated ICD discharges. The ventricular fibrillation was reproducibly triggered by a single premature ventricular complex with a specific QRS morphology. Radiofrequency catheter ablation was carried out to eradicate this complex. No ventricular fibrillation has developed after this procedure, and the patient does not require drug treatment.
    Heart (British Cardiac Society) 08/2001; 86(1):E3. · 5.01 Impact Factor
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    ABSTRACT: We sought to determine the prevalence of right bundle branch block (RBBB) and ST segment elevation in the working Japanese population, as well as the event rate during a three-year prospective follow-up period. A poor prognosis of RBBB and ST segment elevation has been reported in Europe and South America, even in asymptomatic patients; however, a large population of asymptomatic patients with sporadic RBBB and ST segment elevation has not been studied. Ten thousand 12-lead electrocardiograms (ECGs) were obtained during annual check-ups of working adults in the Tokyo area. This three-year prospective follow-up study consisted of 105 patients, including 20 with ventricular fibrillation, 18 with syncope and 67 who were asymptomatic. They were registered from 46 institutions in Japan. The prevalence of ECG abnormalities in working adults was 0.16%. A coved-type ST segment elevation was related to a history of cardiac events, and 18% of registered patients had PR prolongation and 9.5% had left-axis deviation. The cumulative cardiac event-free rate was 67.6% in the symptomatic group and 93.4% in the asymptomatic group (p = 0.0004) after three years. The recurrence rate of cardiac events in symptomatic patients was similar to that reported previously, but it was very low in sporadic asymptomatic patients. The ECG findings may help us to select patients for further examination and more accurate evaluation of their prognoses.
    Journal of the American College of Cardiology 07/2001; 37(7):1916-20. · 14.09 Impact Factor
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    ABSTRACT: Based on the results of the Cardiac Arrhythmia Suppression Trial (CAST), strategies for the treatment of tachyarrhythmias have changed rapidly. The Japanese Antiarrhythmics Long-Term (JALT) study was planned to investigate the present methods for choosing antiarrhythmic drugs, and the effects on long-term prognosis in patients with tachyarrhythmias in Japan. Following a 6-month preliminary study (JALT-1), there was a multicenter nonrandomized prospective study (JALT-2), with a 2-year follow-up, of patients with paroxysmal atrial fibrillation (PAF), sustained ventricular tachycardia (SVT) and nonsustained VT (NSVT). Four hundred fifty-five patients were registered, and 361 of them (79%) were analyzed. Cerebral infarction occurred in 10 of 193 patients (5.2%) with PAF. Transition to chronic AF was observed in 21 patients (10.9%), but in none of the patients receiving Ca antagonist therapy. Twenty-five patients died: 5 deaths were arrhythmic, 10 were because of pump failure, and 9 were noncardiac. The most significant difference in drug selection between JALT-1 and JALT-2 was the increase in the use of slow kinetic Na channel blockers for PAF and the decrease in the use of the same agents for VT in the JALT-2 study. A marked change of therapeutic strategy occurred in JALT-2 compared with JALT-1. Most patients with a poor prognosis had underlying heart diseases and heart failure, but the per annum rate of death by arrhythmia and pump failure in JALT-2 was less than that in JALT-1.
    Japanese Circulation Journal 04/2001; 65(4):275-8.
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    ABSTRACT: Although immunoapheresis removing autoantibodies against the second extracellular domain of beta(1)-adrenergic receptors (ARs) improves cardiac function in patients with cardiomyopathy, the underlying mechanisms have not been defined. We examined the role of autoimmunity against the domain in the development of cardiac dysfunction in vivo. Japanese white rabbits were immunized with a synthetic peptide corresponding to the second extracellular loop of beta(1)-AR once a month with (beta+biso rabbits, n=10) or without (beta rabbits, n=13) bisoprolol treatment (2 mg/kg per day). Control rabbits received vehicle without bisoprolol treatment (n=13). Autoantibodies of IgG isotype against the domain were persistently detected in beta and beta+biso rabbits. Purified IgG from sera of beta and beta+biso rabbits increased cAMP production in a rabbit cardiac membrane preparation, which was blocked by bisoprolol. At 3 months, beta-AR uncoupling with increased G protein-coupled receptor kinase 5 (GRK5) expression was found in beta rabbits. At 6 months, left ventricular hypertrophy was noted with hemodynamic derangements in beta rabbits. This was accompanied by decreased beta(1)-AR density and increased inhibitory G protein and GRK5 expression, which were related to marked decrease in membrane cAMP production. These changes in beta rabbits at 6 months were prevented in beta+biso rabbits. There was no difference in the plasma norepinephrine concentration in the 3 groups over the observation period. Thus, autoimmunity against the second extracellular loop of beta(1)-ARs induced profound beta-AR desensitization and myocardial hypertrophy in vivo, associated with cardiac dysfunction. Sustained sympathomimetic-like actions of autoantibodies against the domain may be partly responsible for these changes.
    Circulation Research 04/2001; 88(6):578-86. · 11.86 Impact Factor

Publication Stats

4k Citations
629.23 Total Impact Points

Institutions

  • 1980–2009
    • Keio University
      • • School of Medicine
      • • Department of Internal Medicine
      Edo, Tōkyō, Japan
  • 1997–2001
    • Jichi Medical University
      • Department of Obstetrics and Gynecology
      Tochigi, Tochigi-ken, Japan
  • 1991–2001
    • Toho University
      • Department of Internal Medicine
      Funabashi, Chiba-ken, Japan
  • 1998
    • Tokyo Dental College
      Edo, Tōkyō, Japan
  • 1987–1998
    • The University of Tokyo
      • • Institute of Medical Science
      • • Institute for Solid State Physics
      Tokyo, Tokyo-to, Japan
  • 1990
    • Osaka University
      • Department of Electronics and Materials Physics
      Suita, Osaka-fu, Japan
  • 1978–1979
    • Thomas Jefferson University Hospitals
      • Division of Hospital Medicine
      Philadelphia, Pennsylvania, United States