Michihiko Kitayama

Kanazawa Medical University, Kanazawa-shi, Ishikawa-ken, Japan

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Publications (12)32.64 Total impact

  • Article: Serum deoxyribonuclease I activity can be a useful diagnostic marker for the early diagnosis of unstable angina pectoris or non-ST-segment elevation myocardial infarction.
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    ABSTRACT: Recently, serum deoxyribonuclease I (DNase I) activity has been highlighted as a potential diagnostic marker for transient myocardial ischemia. To evaluate whether serum DNase I activity can be a useful biomarker for diagnosing unstable angina pectoris (UAP) or non-ST-segment elevation myocardial infarction (NSTEMI), we investigated serial changes in DNase I levels after chest pain in UAP and NSTEMI (UAP/NSTEMI) patients. Thirty-three and ten patients classified into the UAP/NSTEMI and the chest pain syndrome (CPS) group, respectively, were enrolled. The serum DNase I activity levels within 3h after chest pain and the absolute median value of percentage differences in serum DNase I activity levels from admission to 3h after hospitalization in the UAP/NSTEMI patients was significantly higher than those in the CPS patients. We evaluated the patients to show positive results for DNase I activity if the serum levels or percentage differences exceeded the corresponding cut-off values. The sensitivity and specificity of DNase I within 6h after chest pain in the UAP/NSTEMI patients without elevated levels of cardiac troponin T and the MB isoenzyme of creatine kinase were 89% and 88%, respectively. Serum DNase I activity can be a useful marker for the early diagnosis of UAP/NSTEMI after the onset of chest pain, irrespective of the evidence of myocardial injury.
    Journal of Cardiology 02/2012; 59(3):258-65. · 1.28 Impact Factor
  • Article: A quantitative coronary angiography-matched comparison between a prospective randomised multicentre cutting balloon angioplasty and bare metal stent trial (REDUCE III) and the Rapamycin-Eluting Stent Evaluation At Rotterdam Cardiology Hospital (RESEARCH) study.
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    ABSTRACT: There remains significant concern about the long-term safety of drug-eluting stents (DES). However, bare metal stents (BMS) have been used safely for over two decades. There is therefore a pressing need to explore alternative strategies for reducing restenosis with BMS. This study was designed to examine whether IVUS-guided cutting balloon angioplasty (CBA) with BMS could convey similar restenosis rates to DES. In the randomised REstenosis reDUction by Cutting balloon angioplasty Evaluation (REDUCE III) study, 521 patients were divided into four groups based on device and IVUS use before BMS (IVUS-CBA-BMS: 137 patients; Angio-CBA-BMS: 123; IVUS-BA-BMS: 142; and Angio-BA-BMS: 119). At follow-up, the IVUS-CBA-BMS group had a significantly lower restenosis rate (6.6%) than the other groups (p=0.016). We performed a quantitative coronary angiography (QCA) based matched comparison between an IVUS-guided CBA-BMS strategy (REDUCE III) and a DES strategy (Rapamycin-Eluting-Stent Evaluation At Rotterdam Cardiology Hospital, the RESEARCH study). We matched the presence of diabetes, vessel size, and lesion severity by QCA. Restenosis (>50% diameter stenosis at follow-up) and target vessel revascularisation (TVR) were examined. QCA-matched comparison resulted in 120-paired lesions. While acute gain was significantly greater in IVUS-CBA-BMS than DES (1.65±0.41 mm vs. 1.28±0.57 mm, p=0.001), late loss was significantly less with DES than with IVUS-CBA-BMS (0.03±0.42 mm vs. 0.80±0.47 mm, p=0.001). However, no difference was found in restenosis rates (IVUS-CBA-BMS: 6.6% vs. DES: 5.0%, p=0.582) and TVR (6.6% and 6.6%, respectively). An IVUS-guided CBA-BMS strategy yielded restenosis rates similar to those achieved by DES and provided an effective alternative to the use of DES.
    EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 08/2010; 6(3):400-6. · 3.29 Impact Factor
  • Article: Levels of serum deoxyribonuclease I activity on admission in patients with acute myocardial infarction can be useful in predicting left ventricular enlargement due to remodeling.
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    ABSTRACT: Serum deoxyribonuclease I (DNase I) activity has recently been highlighted as a potential diagnostic marker for the early detection of an acute myocardial infarction (AMI). We evaluated whether the serum DNase I activity was associated with the parameters of the left ventricular (LV) remodeling after an AMI. We measured the serum DNase I activity in 45 patients with an AMI who were admitted to our hospital within approximately 4 h of the onset of their chest pain. We also evaluated the LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), and LV end-systolic volume (LVESV) of each patient by echocardiography at the time of admission and at 6 months after the onset of the AMI. The serum DNase I activity peaked at 3.5+/-2.0 h after the onset of the symptoms in the patients with an AMI, thereafter exhibiting a time-dependent decline within 12 h, and a return to the basal level within 24 h in almost all cases. Neither the LVEF, LVEDV, nor LVESV in each patient on admission exhibited a significant correlation to the peak levels of the serum DNase I activity. Although there was no correlation between the peak DNase I activity and LVEF at 6 months after the onset, a significant positive correlation of the peak DNase I activity with LVEDV and LVESV (r=0.48, p<0.001 and r=0.34, p=0.02, respectively) was found. Furthermore, the LVEDV at 6 months after the onset in the high DNase I activity group (> 17.9 U/L) were significantly higher than those in the low DNase I activity group (< or = 17.9 U/L) (118.0+/-28.2 ml vs 89.3+/-25.4 ml, p=0.026). The serum DNase I activity level may predict LV enlargement associated with remodeling after an AMI.
    Journal of Cardiology 05/2009; 53(2):196-203. · 1.28 Impact Factor
  • Article: [Marked PT-INR prolongation associated with appetite loss due to urinary tract infection in a late elderly case with chronic atrial fibrillation].
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    ABSTRACT: An 80-year old woman presented with macroscopic hematuria on June 4(th), 2008. She had been suffering from general malaise and appetite loss since about 10 days previously. She had received anticoagulant therapy with warfarin due to chronic atrial fibrillation and PT-INR was well controlled between 1.6-2.2. When she presented, PT-INR was 12.88, and urinary tract infection (UTI) and hypoalbuminemia (2.2 g/dl) were observed. Therefore, warfarin therapy was discontinued, and antibiotics and vitamin K were administered. Normalization of PT-INR resulted in the disappearance of hematuria and UTI improved as a result of antibiotics administration. As the appetite loss improved, for serum albumin level increased. The previous dose of warfarin achieved PT-INR around 1.8. Her drug compliance had been good, and she took no drug nor food which could interact with warfarin. We also found no liver dysfunction, acute renal failure, malignancy, nor hyper- or hypo-thyroidism. Hypoalbuminemia caused by appetite loss due to UTI seems very likely to increase concentration of circulating free warfarin resulting in extreme prolongation of PT-INR. Our findings in the present case may suggest that we should pay more attention on changes of drug pharmacokinetics in elderly patients because of their poor adaptation to their circumstances such as infection or dehydration.
    Nippon Ronen Igakkai Zasshi Japanese Journal of Geriatrics 01/2009; 46(6):541-4.
  • Article: Serum deoxyribonuclease I activity can be used as a novel marker of transient myocardial ischaemia: results in vasospastic angina pectoris induced by provocation test.
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    ABSTRACT: Serum deoxyribonuclease I (DNase I) activity has recently been highlighted as a potential diagnostic marker for detection of acute myocardial infarction. To evaluate whether serum DNase I activity is useful for detection of myocardial ischaemia, we investigated alteration of its levels after onset of vasospastic angina pectoris (VSAP), resulting in transient myocardial ischaemia, induced by the intracoronary ergonovine provocation test. Twenty-nine consecutive patients with suspected VSAP were subjected to the test. Patients were categorized as VSAP-positive (n = 13) or -negative (n = 16) based on development of angina. Serum samples were examined for DNase I activity before, immediately after, and 3, 6, and 24 h after the provocation tests. The serum DNase I activity increased significantly from the baseline 3 h after the provocation test in 11 patients of the VSAP-positive group whose levels of troponin T were within the normal range. Median of the percentage differences from the baseline in serum DNase I activity 3 h after the test was 32.1% (25th and 75th percentile: 28.6 and 42.0%, respectively; P = 0.000012). In the VSAP-negative group, levels of DNase I activity remained unchanged at any point of time after the provocation test. Transient myocardial ischaemia resulting from VSAP induces a significant elevation of serum DNase I activity. Therefore, serum DNase I activity may be applicable as a useful marker for detecting transient myocardial ischaemia.
    European Heart Journal 01/2008; 28(24):2992-7. · 10.48 Impact Factor
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    Article: Role of a novel conduction pattern around the coronary sinus in cavotricuspid isthmus dependent right atrial flutter.
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    ABSTRACT: We tested our hypothesis that, in atrial flutter (AFL) dependent on the cavotricuspid isthmus (CTI), lower loop reentry is the common pathway route at the coronary sinus posterior site, and thus, dual loop reentry is a common circular pattern. We studied 25 patients with CTI-dependent AFL, 16 with chronic counterclockwise atrial flutter (CCW-AFL) and 9 with clockwise atrial flutter (CW-AFL) and determined the precise reentry circuitry, especially for conduction patterns around the coronary sinus orifice, using electroanatomical mapping. We measured post pacing interval and tachycardia cycle length during entrainment from sites within the flutter circuit. The coronary sinus anterior pacing site was within the AFL circuit in 16 of the 25 CCW-AFL patients, and in 6 of the 9 CW-AFL patients. Both the coronary sinus anterior and posterior sites were within the AFL circuit in 8 of 16 CCW-AFL and 8 of the 9 CW-AFL patients. Results of 3-dimensional activation mapping suggest that all of these patients have a dual loop reentry circuit, and that coronary sinus posterior conduction broke through the eustachian valve/ridge. Coronary sinus posterior conduction consisted of the flutter circuit and appeared to be critical for maintaining AFL.
    Journal of Cardiology 08/2007; 50(1):1-10. · 1.28 Impact Factor
  • Article: Impact of cutting balloon angioplasty (CBA) prior to bare metal stenting on restenosis.
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    ABSTRACT: While stent restenosis and late thrombosis still occur even with drug-eluting-stents (DES), there remains a need to explore other strategies for preventing restenosis. Five hundred and twenty-one patients were randomized: 260 to cutting-balloon angioplasty (CBA) before bare-metal stent (CBA-BMS) and 261 to balloon-angioplasty (BA) before BMS (BA-BMS). Intravascular ultrasound (IVUS)-guided procedures were performed in 279 (54%) patients and angiographic guidance was used in the remainder. Minimal lumen diameter was significantly greater in CBA-BMS than BA-BMS (2.65+/-0.40 mm vs 2.52+/-0.4 mm, p<0.01) and % diameter stenosis (%DS)-post was less in CBA-BMS than BA-BMS (14.0+/-5.9% vs 16.3+/-6.8%, p<0.01). %DS-follow-up was subsequently less in CBA-BMS than BA-BMS (32.4+/-15.1% vs 35.4+/-15.3%, p<0.05) associated with lower rates of restenosis in CBA-BMS than BA-BMS (11.8% vs 19.6%, p<0.05) and less target lesion revascularization (TLR) in CBA-BMS than BA-BMS (9.6% vs 15.3%, p<0.05). Patients were divided into 4 groups based on the device used before stenting and IVUS use (IVUS-CBA-BMS: 137 patients; Angio-CBA-BMS: 123; IVUS-BA-BMS: 142; and Angio-BA-BMS: 119). At follow-up IVUS-CBA-BMS had a significantly lower restenosis rate (6.6%) than Angio-CBA-BMS (17.9%), IVUS-BA-BMS (19.8%) and Angio-BA-BMS (18.2%, p<0.05). Restenosis and TLR were significantly lower in CBA-BMS than BA-BMS. This favorable outcome was achieved because of the lower restenosis rate conferred by the IVUS-guided-CBA-BMS strategy (6.6%). The restenosis rates obtained with this strategy were comparable to those achieved with DES.
    Circulation Journal 01/2007; 71(1):1-8. · 3.77 Impact Factor
  • Article: Assessment of global and regional left ventricular function by electrocardiographic gated N-13 ammonia positron emission tomography in patients with coronary artery disease.
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    ABSTRACT: Electrocardiographic gated 13N-ammonia positron emission tomography (PET) enables simultaneous assessment of myocardial blood flow and left ventricular (LV) function. The aim of this study was to assess the accuracy of gated 13N-ammonia PET for evaluating global and regional LV function in patients with coronary artery disease (CAD) in comparison with conventional left ventriculography (LVG). Fifty-four patients with CAD underwent gated 13N-ammonia PET and LVG. The LV end-diastolic and end-systolic volumes (LVEDV, LVESV) and ejection fraction (LVEF) by gated 13N-ammonia PET were calculated using Cedars-Sinai automated quantitative gated single photon emission computed tomography (QGS) and compared with those obtained by LVG. The regional wall motion (RWM) was visually scored, and compared with that on LVG. There were good correlations between the 2 methods for LVEF, LVEDV and LVESV (R=0.828, R=0.821 and R=0.874 respectively). The RWM assessed by gated 13N-ammonia PET also agreed well with that by LVG (complete agreement was 70.4%, kappa=0.58). Gated 13N-ammonia PET combined with QGS works reasonably well for the assessment of both global and regional LV function in CAD patients, although additional calibration may be necessary.
    Circulation Journal 03/2005; 69(2):177-82. · 3.77 Impact Factor
  • Article: Ischemic preconditioning and morphine attenuate myocardial apoptosis and infarction after ischemia-reperfusion in rabbits: role of delta-opioid receptor.
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    ABSTRACT: We examined whether ischemic preconditioning (IPC) attenuates ischemia-reperfusion injury, in part, by decreasing apoptosis and whether the delta-opioid receptor (DOR) plays a pivotal role in the regulation of apoptosis. Rabbits were subjected to 30-min coronary artery occlusion (CAO) and 180 min of reperfusion. IPC was elicited with four cycles of 5-min ischemia and 10-min reperfusion before CAO. Morphine (0.3 mg/kg iv) was given 15 min before CAO. Naloxone (Nal; 10 mg/kg iv) and naltrindole (Nti; 10 mg/kg iv), the respective nonselective and selective DOR antagonists were given 10 min before either morphine or IPC. Infarct size (%risk area) was reduced from 46 +/- 3.8 in control to 11.6 +/- 1.0 in IPC and 19.5 +/- 3.8 in the morphine group (means +/- SE; P < 0.001 vs. control). Nal blocked the protective effects of IPC and morphine, as shown by the increase in infarct size to 38.6 +/- 7.2 and 44.5 +/- 1.8, respectively. Similarly, Nti blocked IPC and morphine-induced protection. The percentage of apoptotic cells (revealed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay) decreased in IPC (3.6 +/- 1.9) and morphine groups (5.2 +/- 1.2) compared with control group (12.4 +/- 1.6; P < 0.001). Nti pretreatment increased apoptotic cells 11.2 +/- 2.2% in IPC and 12.1 +/- 0.8% in morphine groups. Nal failed to block inhibition of apoptosis in the IPC group (% of cells: 5.7 +/- 1.3 vs. 3.6 +/- 1.9 in IPC alone; P > 0.05). These results were also confirmed by nucleosomal DNA laddering pattern. We conclude that IPC reduces lethal injury, in part, by decreasing apoptosis after ischemia-reperfusion and activation of the DOR may play a crucial role in IPC or morphine-induced myocardial protection.
    AJP Heart and Circulatory Physiology 10/2004; 287(4):H1786-91. · 3.71 Impact Factor
  • Article: Imbalance of sex hormone levels in men with coronary artery disease.
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    ABSTRACT: Sex hormones are thought to play a key role in atherogenesis, but the available evidence is inconclusive, partly because of a lack of accuracy in measurement. The aim of the study was to investigate the potential role of sex hormones in coronary atherosclerosis. We prospectively applied a simple highly-sensitive method using solid-phase extraction followed by radioimmunoassay. Both phases were carried out using commercially available kits to determine levels of estradiol (E2). We also measured the levels of free testosterone (FT), dehydroepiandrosterone sulfate, luteinizing hormone, follicle-stimulating hormone, and progesterone in 236 consecutive male patients with angiographically-defined stable coronary artery disease and in 143 disease-free and age-matched controls. The levels of highly-sensitive E2 and FT in patients and controls differed slightly in opposing directions, but neither difference reached statistical significance. However, the ratio of FT to highly-sensitive E2 in patients was significantly higher than in the controls (mean +/- SD; 2.50 +/- 1.89 versus 2.06 +/- 1.14, P = 0.018), and this difference remained significant after adjustments for age and body mass index had been made. Multiple regression analysis revealed that age, the association of diabetes, and the presence of coronary atherosclerosis were significantly and independently associated with the values of the FT/highly-sensitive E2 ratio. Other hormones examined did not differ significantly between the patients and the controls. Highly-sensitive E2 measurement demonstrated a significant imbalance of FT to E2 in male patients with coronary artery disease, but individual sex hormone levels did not differ between the patients and the controls.
    Coronary Artery Disease 07/2004; 15(4):199-203. · 1.24 Impact Factor
  • Article: Pretreatment with tyrosine kinase inhibitor attenuates the reduction of apoptosis 24 h after ischemic preconditioning.
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    ABSTRACT: We investigated whether ischemic preconditioning (PC) attenuates ischemia/reperfusion-induced injury in part by decreasing apoptosis and whether tyrosine kinase (TK) can regulate the signaling pathway leading to apoptosis in delayed cardioprotection. Six groups of rabbits were studied in the early phase (EP) and in the delayed phase (DP): (1) sham-operated control animals were received vehicle only (Veh-sham); (2) rabbits that received I.V. genistein (a nonspecific TK inhibitor) 10 min before ischemia (Gen-sham); (3) rabbits that received I.V. daidzein (an inactive structural analog of genistein) 10 min before ischemia (Dzn-sham); (4) rabbits preconditioned with 4 cycles of 5-min occlusion of left anterior descending coronary artery (LAD) and 10-min reperfusion (PC); (5) rabbits that received I.V. genistein, 10 min before PC (Gen-PC); (6) rabbits that received I.V. daidzein 10 min before PC (Dzn-PC). All rabbits underwent 30-min ischemia followed by 180-min reperfusion. Infarct size in the PC, Gen-PC, and Dzn-PC groups in the EP was significantly (p < 0.0001) reduced relative to controls Gen and Dzn. Delayed cardioprotection was blocked significantly (p < 0.0001) by genistein. In the EP, apoptosis was significantly (p < 0.0001) decreased in PC, Gen-PC, and Dzn-PC groups relative to controls Gen and Dzn. In the DP, a reduction of apoptosis was not seen in the Gen-PC group. This study suggests that PC reduces ischemic injury in part by decreasing apoptosis after ischemia/reperfusion and also that TK phosphorylation is involved in the signal transduction cascade leading to the decline of apoptosis in the DP.
    The Japanese Journal of Physiology 04/2004; 54(2):143-51. · 1.04 Impact Factor
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    Article: Case report: unstable angina with flow-fatty acid metabolism mismatch and reverse flow-glucose metabolism mismatch patterns.
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    ABSTRACT: A 79-year-old man with unstable angina underwent an emergency coronary angiography, and percutaneous balloon angioplasty was performed for LCX. Left ventriculography showed hypokinesis in the posterior wall, inferior and apical wall immediately after the PCI therapy. The defects on 123I-BMIPP SPECT seen in the inferior, posterior and lateral wall were more extensive than those observed on 99mTc-MIBI SPECT, and a flow-fatty acid metabolism mismatch pattern was observed. The 18F-FDG PET showed reduced uptake in the lateral segment, although 13N-NH3 PET showed normal perfusion, and a reverse flow-glucose metabolism mismatch pattern was observed. Left ventriculography showed significant improve to normal contraction on the 3-month follow up, and there was not significantly reduced uptake in 99mTc-MIBI SPECT, 123I-BMIPP SPECT, 13N-NH3 PET or 18F-FDG PET.
    Annals of Nuclear Medicine 01/2004; 17(8):699-702. · 1.50 Impact Factor