Y Toyama

Kagoshima University, Kagosima, Kagoshima, Japan

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Publications (13)58.44 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The association between myocardial infarction (MI) and the R353Q polymorphism of the Factor VII (FVII) gene, which reportedly influences FVII concentrations, activated Factor VII (FVIIa), or FVII antigen (FVIIag), remains controversial. The present case - control study in 127 Japanese men with their first MI at or before 45 years of age and 150 matched healthy controls was designed to clarify this association in premature MI. R353Q polymorphism was determined by polymerase chain reaction, and plasma concentrations of FVIIa and FVIIag were assayed. The distribution of the RR, RQ, and QQ genotypes with respect to R353Q polymorphism was 117, 10, and 0 in the patients, and 131, 17, and 2 in the controls. The Q allele was negatively associated with premature MI (odds ratio =0.41, p=0.038). The plasma concentration of FVIIa was slightly higher in patients (55.1+/-40.9 U/L) than in controls (44.8+/-20.2 U/L), but not significantly (p=0.078); the plasma concentration of FVIIag did not differ between patients (88.7+/-15.7%) and controls (87.0+/-9.0%) (p=0.557). Plasma FVIIa concentrations were influenced by R353Q polymorphism (p<0.001). The Q allele may be protective against premature MI.
    Circulation Journal 06/2004; 68(6):520-5. · 3.58 Impact Factor
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    ABSTRACT: The rapid cardiac troponin T (cTnT) test is widely used to detect myocardial necrosis in the emergency setting. This assay system is rapid and myocardial-specific, but the plasma cTnT concentration is difficult to determine quantitatively. A recently developed bedside cTnT and myoglobin (Mb) analyzer (CARDIAC system) was evaluated. The new CARDIAC system was used to measure plasma cTnT and Mb levels, and serum levels of creatine kinase MB isoenzyme (CK-MB), cTnT and Mb were measured by conventional assays in 160 consecutive emergency patients with suspected acute myocardial infarction. The sensitivity of cTnT for identifying acute myocardial infarction was 76%, significantly higher than that of Mb (67%, p < 0.01) and CK-MB (54%, p < 0.05). The diagnostic sensitivities in patients admitted < or = 3 hr and 3-6 hr after onset were 52% and 65% for cTnT, 60% and 90% for Mb, and 36% and 50% for CK-MB, respectively. These sensitivities of Mb were significantly higher than those of CK-MB but not cTnT. However, the sensitivity of cTnT (100%) was significantly higher than that of Mb (58%, p < 0.01) and CK-MB (70%, p < 0.001) in patients admitted > 6 hr after onset. The specificities of cTnT, Mb and CK-MB were 96%, 76% (p < 0.001 vs cTnT and CK-MB) and 95%, respectively. Therefore, cTnT (86%) had significantly (p < 0.001) higher diagnostic accuracy compared with Mb (71%) and CK-MB (75%). Combination diagnosis using cTnT and Mb showed the highest sensitivity (86%) compared with cTnT (p < 0.05) and Mb (p < 0.001). The correlation coefficients between the levels measured by CARDIAC system and those by ordinary assays were 0.98 in cTnT and 0.97 in Mb. Bedside rapid quantitative assays of cTnT and Mb are useful as a point of care test for the diagnosis of acute myocardial infarction.
    Journal of Cardiology 02/2003; 41(2):55-62. · 2.30 Impact Factor
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    ABSTRACT: The purpose of this study was to determine the mechanism by which 60 degrees C sauna treatment improves cardiac function in patients with chronic heart failure (CHF). We have previously reported that repeated 60 degrees C sauna treatment improves hemodynamic data and clinical symptoms in patients with CHF. We hypothesized that the sauna restores endothelial function and then improves cardiac function. Twenty patients (62 plus minus 15 years) in New York Heart Association (NYHA) functional class II or III CHF were treated in a dry sauna at 60 degrees C for 15 min and then kept on bed rest with a blanket for 30 min, daily for two weeks. Ten patients with CHF, matched for age, gender and NYHA functional class, were placed on a bed in a temperature-controlled (24 degrees C) room for 45 min as the nontreated group. Using high-resolution ultrasound, we measured the diameter of the brachial artery at rest and during reactive hyperemia (percent flow-mediated dilation, %FMD: endothelium-dependent dilation), as well as after sublingual administration of nitroglycerin (%NTG: endothelium-independent dilation). Cardiac function was evaluated by measuring the concentrations of plasma brain natriuretic peptide (BNP). Clinical symptoms were improved in 17 of 20 patients after two weeks of sauna therapy. The %FMD after two-week sauna treatment significantly increased from the baseline value, whereas the %NTG-induced dilation did not. Concentrations of BNP after the two-week sauna treatment decreased significantly. In addition, there was a significant correlation between the change in %FMD and the percent improvement in BNP concentrations in the sauna-treated group. In contrast, none of the variables changed at the two-week interval in the nontreated group. Repeated sauna treatment improves vascular endothelial function, resulting in an improvement in cardiac function and clinical symptoms.
    Journal of the American College of Cardiology 04/2002; 39(5):754-9. · 14.09 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2002; 39:134-134.
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    ABSTRACT: We sought to determine whether sauna therapy, a thermal vasodilation therapy, improves endothelial function in patients with coronary risk factors such as hypercholesterolemia, hypertension, diabetes mellitus and smoking. Exposure to heat is widely used as a traditional therapy in many different cultures. We have recently found that repeated sauna therapy improves endothelial and cardiac function in patients with chronic heart failure. Twenty-five men with at least one coronary risk factor (risk group: 38 +/- 7 years) and 10 healthy men without coronary risk factors (control group: 35 +/- 8 years) were enrolled. Patients in the risk group were treated with a 60 degrees C far infrared-ray dry sauna bath for 15 min and then kept in a bed covered with blankets for 30 min once a day for two weeks. To assess endothelial function, brachial artery diameter was measured at rest, during reactive hyperemia (flow-mediated endothelium-dependent dilation [%FMD]), again at rest and after sublingual nitroglycerin administration (endothelium-independent vasodilation [%NTG]) using high-resolution ultrasound. The %FMD was significantly impaired in the risk group compared with the control group (4.0 +/- 1.7% vs. 8.2 +/- 2.7%, p < 0.0001), while %NTG was similar (18.7 +/- 4.2% vs. 20.4 +/- 5.1%). Two weeks of sauna therapy significantly improved %FMD in the risk group (4.0 +/- 1.7% to 5.8 +/- 1.3%, p < 0.001). In contrast, %NTG did not change after two weeks of sauna therapy (18.7 +/- 4.2% to 18.1 +/- 4.1%). Repeated sauna treatment improves impaired vascular endothelial function in the setting of coronary risk factors, suggesting a therapeutic role for sauna treatment in patients with risk factors for atherosclerosis.
    Journal of the American College of Cardiology 10/2001; 38(4):1083-8. · 14.09 Impact Factor
  • Journal of Cardiac Failure - J CARD FAIL. 01/1999; 5(3):84-84.
  • Journal of Cardiac Failure - J CARD FAIL. 01/1999; 5(3):75-75.
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    ABSTRACT: The use of transthoracic color and pulsed Doppler echocardiography to detect intramyocardial coronary artery flow in humans was evaluated in 18 normal healthy subjects (mean age 54 years) and in 16 patients with hypertrophic cardiomyopathy (HCM; mean age 59 years) to measure the intramyocardial coronary artery flow velocity at the ventricular septum and the apex using a 10-5 or 7-4 MHz transducer. Linear inflow color Doppler signals which passed the interventricular septum were demonstrated in 15 of 18 normal subjects (83%) and 15 of 16 patients with HCM (94%). The phasic flow velocities measured by pulsed Doppler echocardiography consisted of two forward flow signals in mid-systole (S-wave) and holodiastole (D-wave), and were obtained in 11 of 18 in normal subjects (61%) and 14 of 16 patients with HCM (88%). The mean peak velocities of the S- and D-waves in patients with HCM (mean [+/-SD] 27 +/- 9 and 86 +/- 23 cm/sec, respectively) were significantly (p < 0.05) higher than those in normal subjects (18 +/- 4 and 54 +/- 11 cm/sec, respectively). At the apex, linear inflow color Doppler signals which passed the myocardium perpendicularly during the whole diastole were demonstrated in 14 of 18 normal subjects (78%) and all 16 patients with HCM (100%). The phasic flow velocities were measured by pulsed Doppler echocardiography in 10 of 18 normal subjects (56%) and 15 of 16 patients with HCM (94%). The mean peak velocities in patients with HCM (74 +/- 27 cm/sec) were significantly (p < 0.05) higher than those in normal subjects (33 +/- 13 cm/sec). Transthoracic color and pulsed Doppler echocardiography can detect intramyocardial coronary artery flow in humans at the interventricular septum and the apex noninvasively.
    Journal of Cardiology 09/1997; 30(3):149-55. · 2.30 Impact Factor
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    ABSTRACT: A warm-water bath (WWB) or sauna bath (SB) has generally been considered inappropriate for patients with severe congestive heart failure (CHF). However, a comprehensive investigation of the hemodynamic effects of thermal vasodilation in CHF has not been previously undertaken. To investigate the acute hemodynamic effects of thermal vasodilation in CHF, we studied 34 patients with chronic CHF (mean age, 58 +/- 14 years). Clinical stages were New York Heart Association functional class II in 2, III in 19, and IV in 13 patients. Mean ejection fraction was 25 +/- 9%. After a Swan-Ganz catheter was inserted via the right jugular vein, the patient had a WWB for 10 minutes at 41 degrees C or an SB for 15 minutes at 60 degrees C. Blood pressure, ECG, echo-Doppler, expiration gas, and intracardiac pressures were recorded before, during, and 30 minutes after each bath. Oxygen consumption increased mildly, pulmonary arterial blood temperature increased by 1.2 degrees C, and heart rate increased by 20 to 25 beats per minute on average at the end of WWB or SB. Systolic blood pressure showed no significant change. Diastolic blood pressure decreased significantly during SB (P < .01). Cardiac and stroke indexes increased and systemic vascular resistances decreased significantly during and after WWB and SB (P < .01). Mean pulmonary artery, mean pulmonary capillary wedge, and mean right atrial pressures increased significantly during WWB (P < .05) but decreased significantly during SB (P < .05). These pressures decreased significantly from the control level after each bath (P < .01). Mitral regurgitation associated with CHF decreased during and 30 minutes after each bath. Cardiac dimensions decreased and left ventricular ejection fraction increased significantly after WWB and SB. In an additional study, plasma norepinephrine increased significantly during SB in healthy control subjects and in patients with CHF and returned to control levels by 30 minutes after SB. Hemodynamics improve after WWB or SB in patients with chronic CHF. This is attributable to the reduction in cardiac preload and afterload. Thus, thermal vasodilation can be applied with little risk if appropriately performed and may provide a new nonpharmacological therapy for CHF.
    Circulation 05/1995; 91(10):2582-90. · 15.20 Impact Factor
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    ABSTRACT: Doppler echocardiography is a widely used noninvasive technique to examine the mitral valve area (MVA) by obtaining mitral pressure half-time (PHT) and to assess the severity of the stenosis. However, several hemodynamic factors influence the PHT and may render the PHT data inaccurate in any measurement of MVA under certain conditions. Using a simple echo-Doppler (E-D) method, we assessed the MVA in a physiological equation. The mitral flow volume (MFV) is represented by MVA x transmitral mean flow velocity (mV) x diastolic filling time (DFT). Thus, the formula can be restated as MVA (cm2) = MFV (cm3)/mV (cm/sec) x DFT (sec). We measured MFV by M-mode, and mV and DFT by continuous wave Doppler echocardiography. This formula was tested in 43 patients with isolated mitral stenosis. MVA was obtained by the PHT and E-D methods, and the data obtained were validated against the results of cardiac catheterization. The results obtained using the E-D method showed much better correlation (r = 0.82) with those of catheterization than those with the PHT method (r = 0.52). The inter- and intraobserver variabilities were checked. The results obtained with the E-D method were found to be reproducible. To further validate the accuracy of the E-D method, MVA was measured by both methods at different R-R intervals after exercise and the results were compared. The MVA obtained by the PHT method showed marked variations; whereas, that obtained by the E-D method remained nearly constant. Similarly, in a patient with atrial fibrillation, the MVA assessed by the PHT method varied from beat to beat; whereas, the fluctuations in MVA were minimal using the E-D method. We concluded that the E-D method can be reliable and clinically easily applicable for the accurate assessment of MVA.
    Journal of Cardiology 02/1992; 22(1):159-69. · 2.30 Impact Factor
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    ABSTRACT: Our clinical experience suggests that anxiety may provoke the augmentation of the degree of mitral valve prolapse (MVP) and change the mitral inflow velocity pattern in patients with MVP. To evaluate this systematically, we recorded 2-dimensional (2-D) and pulsed wave Doppler echocardiograms during acute mental stress in eight patients with MVP and eight age-matched normal subjects. Acute mental stress was administered by applying arithmetical task or reminding each patient of their most uncomfortable memories. Heart rate and blood pressure were significantly increased during mental stress and returned to the control level within a few minutes after its release in both groups. 2-D and Doppler echocardiograms were constantly recorded before, during and after acute mental stress. MVP was prominently augmented during mental stress in three of the eight patients. During mental stress, the mitral inflow velocity decreased in the rapid filling phase (R) and increased in the atrial filling phase (A), resulting in significant increase of the A/R in seven of the eight patients with MVP, especially in the patients associated with an increase of MVP. In normal subjects, mitral valve prolapse did not develop and the A/R was minimally increased or remained almost the same during mental stress. In conclusion, mental stress echocardiography seems to be a useful provocation test for the assessment of MVP and it is further expected to propose a lot of potential applications as a new method of stress echocardiography.
    Journal of cardiology. Supplement. 02/1990; 23:61-9; discussion 70-2.
  • Journal of Cardiology 02/1990; 20(4):1021-4. · 2.30 Impact Factor
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    ABSTRACT: The acute hemodynamic effects of thermal vasodilation caused by exposure to hot water bath or sauna in chronic congestive heart failure were investigated in 32 patients (mean age 57 +/- 15 years old) with dilated cardiomyopathy (25 idiopathic and 7 ischemic). The clinical symptoms were New York Heart Association Class II in 2 patients, III in 17 and IV in 13, and the mean ejection fraction was 25 +/- 9% (9-44%). Exposure to hot water bath was for 10 minutes at 41 degrees C in a semi-sitting position, and to sauna for 15 minutes at 60 degrees C in a supine position using a special far infrared ray sauna chamber. Blood pressure, electrocardiogram, two-dimensional and Doppler echocardiograms, expiration gas, and intracardiac pressure tracings were recorded before (control), during, and 30 minutes after hot water bath or sauna. 1. The increase in oxygen consumption was only 0.3 Mets during hot water bath or sauna, and returned to the control level 30 minutes later. 2. The deep temperature in the main pulmonary artery increased by 1.0-1.2 degrees C on average at the end of hot water bath or sauna. 3. Heart rate increased significantly (p < 0.01) by 20-25/min during bathing and still increased 30 min later. 4. Systolic blood pressure did not change significantly during and after hot water bath or sauna, while, diastolic blood pressure decreased significantly during (p < 0.05) and after sauna (p < 0.01), and after hot water bath (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
    Journal of Cardiology 24(3):175-83. · 2.30 Impact Factor

Publication Stats

225 Citations
58.44 Total Impact Points

Institutions

  • 1990–2004
    • Kagoshima University
      • • Department of Cardiovascular Surgery
      • • Department of Internal Medicine
      • • Department of Rehabilitation and Physical Medicine
      Kagosima, Kagoshima, Japan