S Ikeda

University of Nagasaki, Nagasaki-shi, Nagasaki-ken, Japan

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Publications (22)32.28 Total impact

  • Article: Significance of Tei-index alterations induced by acute preload reduction with hemodialysis.
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    ABSTRACT: The load dependence of Tei-index, an index to estimate combined systolic and diastolic ventricular functions, remains controversial. Moreover, its significance in the setting of acute preload reduction including hemodialysis (HD) remains unknown. Therefore, we examined the significance of the Tei-index in HD patients. Doppler echocardiographic parameters of 42 patients with normal left ventricular ejection fraction (LVEF) were evaluated before and after HD. Based on the index of body water excess calculated using a Crit-Line monitor, the patients were assigned to Group A (normal hydration approximately overhydration) and Group B (risk of pulmonary congestion). Group A was younger and had a shorter isovolumic relaxation time (IRT) than Group B before HD. Hemodialysis significantly increased the Tei-index of Group A, which was derived from prolonging IRT and isovolumic contraction time and shortening the ejection time without changing LVEF. Changes in the Tei-index (DeltaTei-index) significantly correlated with the rate at which blood volume decreased. They were derived from graphs generated using the Crit-Line monitor. Furthermore, the DeltaTei-index inversely correlated with the Tei-index before HD. These findings suggest that the Tei-index is preload-dependent, which is related to changes in volume and speed. Thus, the Tei-index should be cautiously interpreted according to various hemodynamic situations. However, the correlation between the DeltaTei-index and the Tei-index before HD implies that the latter could be a good indicator of effective fluid removal by HD.
    Clinical nephrology 08/2008; 70(1):41-7. · 1.17 Impact Factor
  • Article: Influence of hemodialysis on echocardiographic Doppler indices of the left ventricle: changes in parameters of systolic and diastolic function and Tei index.
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    ABSTRACT: Numbers of previous studies have evaluated the influence of dialysis-induced altered loading condition on Doppler-echocardiographic indices of left ventricle in patients with chronic renal failure. It has been suggested that most of Doppler-derived indices are preload-dependent. On the other hand, there are no studies that have evaluated the influence of hemodialysis on Tei index; a new Doppler-derived index obtained by isovolumetric contraction time plus isovolumetric relaxation time divided by ejection time. The aim of this study is to evaluate whether Tei index is also influenced by dialysis-induced altered loading condition as well as other Doppler-derived indices, and to assess the possibility that Tei index is also preload-dependent. Thirty-two patients with chronic renal failure (21 men and 11 women, aged 48-93 years) on maintenance hemodialysis were evaluated for Doppler-derived indices before and after hemodialysis. We studied parameters of diastolic function (peak velocities of mitral inflow in early diastole (E) and late diastole from atrial filling (A), ratio of A to E (A/E), deceleration time (DT), and isovolumetric relaxation time (IRT)), parameters of systolic function (ejection time (ET), pre-ejection period (PEP), ratio of PEP to ET (PEP/ET), and isovolumetric contraction time (ICT)) and Tei index. Hemodialysis resulted in significant decreases in E, increase in A/E, prolongation of IRT, no change in A and DT; significant prolongation of ICT and PEP, shortening of ET, and increase in PEP/ET and a significant increase in Tei index (0.42 +/- 0.16 vs 0.51 +/- 0.16, p < 0.0001). When patients were subdivided into 2 groups based on weight loss after hemodialysis (> or = 1.5 kg and < 1.5 kg), only the group that lost > or = 1.5 kg had significant change in Tei index before and after hemodialysis (0.40 +/- 0.15 vs 0.52 +/- 0.17, p = 0.0002). This study demonstrates that not only most of Doppler-derived indices but also Tei index is affected by dialysis-induced altered loading condition and suggests that Tei index is possibly preload-dependent.
    Clinical nephrology 03/2003; 59(3):180-5. · 1.17 Impact Factor
  • Article: Echocardiographic evaluation of right cardiac function in patients with chronic pulmonary diseases.
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    ABSTRACT: It is clinically important to evaluate the severity of right ventricular (RV) overload in patients with chronic pulmonary diseases (CPD). For such evaluation, echocardiography has been widely used because the procedure is noninvasive and can be performed repeatedly. We evaluated the severity of RV overload in CPD patients to assess the usefulness of pulsed Doppler echocardiography. The A/E ratio and deceleration time of early RV inflow velocity correlated significantly with the mean pulmonary artery pressure (MPAP) both in patients with and without CPD. The acceleration time/RV ejection time (AcT/RVET) was significantly lower in CPD patients than control subjects and correlated significantly with MPAP. Furthermore, AcT/RVET improved in patients with mild respiratory failure after oxygen therapy, along with a decrease in MPAP. We also compared the new index of myocardial performance (NI) in control subjects and patients with pulmonary tuberculosis sequelae (TB) undergoing home oxygen therapy. The NI was significantly higher in the TB group. Although these results were satisfactory, the pulsed Doppler echocardiography has certain disadvantages because monitoring is influenced by anatomical factors and it is difficult to perform in patients with atrial fibrillation or tachycardia. We conclude that echocardiography using a Doppler method is a useful noninvasive technique for assessment of the right heart system. The precision of this procedure can be improved by combination with other echocardiographic indices of RV overload.
    Japanese Heart Journal 08/2001; 42(4):483-93. · 0.40 Impact Factor
  • Article: Successful removal of a left main coronary artery thrombus induced by vasospasm to the aorta [correction of vasospasm of the aorta] after the injection of contrast medium.
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    ABSTRACT: A 51-year-old woman with acute myocardial infarction underwent emergency coronary angiography. The patient had an episode of idiopathic thrombocytopenic purpura, and underwent splenectomy at the age of 36. On admission, platelet count in the peripheral blood was 43.2x10(4)/microl. During the initial emergency left coronary angiography, a thrombus was detected in the left main trunk. The thrombus was drawn back to the orifice of the left coronary artery, and finally disappeared into the aorta by injecting contrast media. After the thrombus disappeared, no stenotic lesion was detected in the left coronary artery. One month later, when acetylcholine-provocation coronary angiography was performed, marked vasospasm was detected in the left coronary arteries. Coronary thrombosis in the patient might have been induced by a coronary spasm, and the presence of thrombocytosis might also have affected the development of a coronary thrombus. However, it was spontaneously drawn back to the aorta by back flow of contrast media, which was injected via the entrance of the left coronary artery. A case of acute myocardial infarction whose thrombus occluded the left main coronary artery and was removed at first injection of contrast media is presented.
    Japanese Circulation Journal 07/2001; 65(6):579-80.
  • Article: [Oral administration of beraprost sodium did not exacerbate pulmonary hypertension with CREST syndrome].
    Nihon Naika Gakkai Zasshi 06/2001; 90(5):881-3.
  • Article: Diagnostic value of pulsed Doppler echocardiography in acute pulmonary thromboembolism--comparison with pulmonary angiography and pulmonary artery pressure.
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    ABSTRACT: The ratio of acceleration time to right ventricular ejection time (AcT/RVET) can be derived from the blood flow patterns recorded by pulsed wave Doppler echocardiography. In chronic cor pulmonale, AcT/RVET negatively correlates with pulmonary artery pressure (PAP). The present study evaluated the diagnostic value of AcT/RVET by comparing this variable with indices derived from pulmonary angiography (PAG) and PAP in 16 patients with acute pulmonary thromboembolism (APTE). AcT/RVET, PAP, and PAG severity indices (Miller index (MI) and UPET objective angiographic index (UI)) were measured during the acute phase on admission and the chronic phase after treatment. In the acute phase, AcT/RVET correlated with mean PAP (mPAP) (r=-0.68, p<0.05) and total pulmonary resistance (TPR) (r=-0.66, p<0.05), but not with MI or UI. During the chronic phase, AcT/RVET did not correlate with mPAP or TPR, but with both PAG indices (MI: r=0.76, p<0.05, UI: r=0.65, p<0.05). Before treatment of the APTE, AcT/RVET remained at low levels and could be used as an index of pulmonary hypertension. After treatment, however, following improvement of PAP, AcT/RVET was not useful for evaluating PAP, but might serve as an index for evaluating the volume of residual thrombi.
    Japanese Circulation Journal 04/2001; 65(3):171-6.
  • Article: Left ventricular mass and global function in essential hypertension after antihypertensive therapy.
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    ABSTRACT: This study compares left ventricular global function in 55 patients (25 with hypertrophy and 30 without hypertrophy) with essential hypertension, whose blood pressure had been stable for longer than 1 year, with that in 35 healthy subjects. Left ventricular global function was calculated using the echocardiographic Doppler index as described by Tei et al. (Tei index). No significant differences were observed in echocardiographic left ventricular systolic function between the three groups. Left ventricular global function differed significantly between the three groups, however, suggesting impaired left ventricular global function even in the absence of left ventricular hypertrophy. Similar changes were observed in the ratio of peak velocity of atrial systole to peak velocity of early diastole during left ventricular inflow waveform (A/E), indicating that this disorder mainly reflects impaired left ventricular diastolic function. Unlike A/E, the Tei index is not affected by increasing age, and, therefore, is appropriate for evaluating left ventricular global function in hypertensive patients, most of whom are middle-aged or older. This index may be useful for determining treatment strategy and evaluating treatment effects.
    The Journal of international medical research 02/2000; 28(1):9-19. · 0.90 Impact Factor
  • Article: Cardiac function in dialysis patients evaluated by Doppler echocardiography and its relation to intradialytic hypotension: a new index combining systolic and diastolic function.
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    ABSTRACT: AIM, PATIENTS AND METHODS: Cardiac function of 40 patients on maintenance dialysis was examined using a new Doppler index combining systolic and diastolic function. Immediately before dialysis, ultrasonic pulsed Doppler was used to measure right and left ventricular inflow and outflow waveforms. The sum of the isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) was calculated by subtracting the ejection time from the interval between the end of an inflow waveform and the start of the next inflow waveform. The new index was obtained by dividing the sum of the two isovolumetric times by the ejection time. Cardiac function was evaluated in dialysis patients and healthy controls using new indices of the right and left heart systems. RESULT: Indices of the right and left heart systems in dialysis patients were significantly higher than those in healthy controls. With respect to hypotension during dialysis, patients were divided into two groups, a group with decreased blood pressure (group A: 27 patients) and a group with normal blood pressure (group B: 13 patients). Only the left heart system index in group A was significantly higher. There were no significant differences in other M-mode Doppler indices between the two groups. CONCLUSION: The new index was a more sensitive evaluator of cardiac function and predictor of hypotension during dialysis compared to standard echocardiographic indices.
    Clinical nephrology 02/2000; 53(1):18-24. · 1.17 Impact Factor
  • Article: Serial changes in negative T wave on electrocardiogram in acute pulmonary thromboembolism.
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    ABSTRACT: A negative T wave is frequently observed in precordial ECG leads in patients with acute pulmonary thromboembolism. We investigated the clinical significance of negative T wave in 15 patients with acute pulmonary thromboembolism who were treated with thrombolytic agents by measuring the mean pulmonary artery pressure and ratio of right to left ventricular end-diastolic diameter using echocardiography and ECG. The study included only patients with massive acute pulmonary thromboembolism of a mean age of 65+/-9.7 years (+/-SD). A negative T wave was observed on admission in 10 patients but was later detected in 14 of the 15 patients. The mean amplitude of the negative T wave increased within 1 week then decreased after thrombolytic treatment. The peak negative amplitude of the T wave was observed from 1 to 7 days (mean, 2.6+/-1.8 days) and disappeared afterwards. During this period, improvements in both the mean pulmonary artery pressure (37.8+/-11.2 to 19.1+/-6.7 mmHg) and the ratio of right to left ventricular end-diastolic diameter (0.97+/-0.16 to 0.51+/-0.13) were noted in all patients. Our results suggest that an increase in the amplitude of negative T wave in precordial leads after thrombolytic therapy in patients with massive acute pulmonary thromboembolism reflects improvement in cardiopulmonary hemodynamics.
    International Journal of Cardiology 01/2000; 72(1):65-72. · 7.08 Impact Factor
  • Article: [Extra-intestinal complications of ulcerative colitis: arteriovenous thrombosis/embolism].
    Y Miyahara, S Ikeda
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    ABSTRACT: Thromboembolic episode is a well known extraintestinal complications of ulcerative colitis, but it is a rare complication in clinically. In the literature there are some interesting observations concerning the factors, may play a major role both in the pathogenesis and in the hypercoagulability in ulcerative colitis. However the exact mechanism of hypercoagulability in patients with ulcerative colitis is still unknown. We reviewed the incidence, the activity and severity of the basic disease, the pathogenesis, the treatment, the prognosis of thromboembolic phenomena in patients with ulcerative colitis.
    Nippon rinsho. Japanese journal of clinical medicine 12/1999; 57(11):2562-5.
  • Article: Liddle's syndrome in an elderly woman.
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    ABSTRACT: A 78-year-old woman with hypertension was hospitalized with acute bronchitis. However, she was also found to have hypernatremia, hypokalemia, and metabolic alkalosis. Detailed examination showed a low plasma renin activity and plasma aldosterone concentration. A provisional diagnosis of Liddle's syndrome was established and the patient was successfully treated with triamterene. Although Liddle's syndrome is generally considered an inherited hypertensive disease found in young people, a review of the literature indicated that muscle weakness is an important clinical finding in elderly patients with this disease. Liddle's syndrome should be considered in the differential diagnosis of hypertension even in elderly individuals.
    Internal Medicine 05/1998; 37(4):391-5. · 0.94 Impact Factor
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    Article: Iodine-123-metaiodobenzylguanidine myocardial imaging in patients with right ventricular pressure overload.
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    ABSTRACT: Iodine-123-metaiodobenzylguanidine ([123I]MIBG) has been used to evaluate the cardiac sympathetic nervous system, particularly that of the left heart. To clarify whether the right ventricular (RV) sympathetic neuronal function could be evaluated by [123I]MIBG myocardial imaging, we applied the technique in patients with pulmonary hypertension that was associated with either chronic pulmonary diseases or pulmonary vascular diseases. All patients underwent right heart catheterization, and right heart hemodynamics were determined during a clinically stable state. SPECT was performed in the resting state 15 min (early imaging) and 4 hr (delayed imaging) postadministration of [123I]MIBG. Seven regions of interest (ROI) were selected on the delayed short-axis images on the RV free wall, left ventricular (LV) free wall and interventricular septum (IVS). We calculated the IVS-to-LV uptake ratio from the scintillation counts of the ROI. Thallium-201 myocardial imaging was also performed within 1 wk after [123I]MIBG imaging. Images obtained with these techniques were analyzed for the RV-to-LV uptake ratio. The IVS-to-LV ratio on [123I]MIBG correlated negatively and significantly with the mean pulmonary arterial pressure (PAm). The RV-to-LV uptake ratio on 201Tl images correlated significantly with PAm. Our results suggest that the uptake ratio of [123I]MIBG in the IVS is a useful index for evaluating the severity of pulmonary hypertension, and that chronic RV pressure overload contributes to disturbances of the cardiac sympathetic nervous system.
    Journal of Nuclear Medicine 09/1996; 37(8):1343-6. · 6.38 Impact Factor
  • Article: [Primary pulmonary artery sarcoma (e.g. spindle cell sarcoma of the pulmonary artery, pulmonary artery leiomyosarcoma)].
    Y Miyahara, S Ikeda, T Naito
    Ryōikibetsu shōkōgun shirīzu. 02/1996;
  • Article: Pulsed Doppler echocardiographic assessment of changes in pulmonary artery pressure during oxygen breathing.
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    ABSTRACT: To validate the use of pulsed Doppler echocardiography in detecting changes in pulmonary artery pressure (PAP), several parameters of flow velocity profiles of the right ventricular outflow tract were compared with changes in PAP and pulmonary vascular resistance measured directly by cardiac catheterization. The study was performed in 33 patients with chronic pulmonary disease (chronic obstructive pulmonary disease or pulmonary fibrosis) or pulmonary thromboembolism, during room air and 100% oxygen breathing. Inhalation of 100% oxygen for 15 min significantly reduced PAP in patients with mild pulmonary hypertension (20 < or = mean PAP < or = 24 mm Hg; control: 21.3 +/- 1.3, O2: 17.9 +/- 2.2 mm Hg, p < 0.05) and those with severe pulmonary hypertension (mean PAP > or = 25 mm Hg; control 44.9 +/- 16.8, O2: 35.4 +/- 13.5 mm Hg, p < 0.05). It also significantly reduced the pulmonary vascular resistance and cardiac output in both groups. The ratio of acceleration time to right ventricular ejection time (AT/RVET), a parameter measured by Doppler echocardiography, correlated significantly with mean PAP during room air (r = 0.73, p < 0.0001) and oxygen breathing (r = 0.64, p < 0.0001). Furthermore, AT/RVET increased significantly in patients with mild pulmonary hypertension and those with severe pulmonary hypertension. Our results suggest that the Doppler technique provides a clinically useful, noninvasive index for assessing changes in PAP during oxygen breathing in patients with pulmonary hypertension complicating chronic pulmonary disease or pulmonary thromboembolism.
    Respiration 01/1996; 63(1):35-41. · 2.26 Impact Factor
  • Article: Assessment of right ventricular diastolic function by pulsed Doppler echocardiography in chronic pulmonary disease and pulmonary thromboembolism.
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    ABSTRACT: We evaluated right ventricular (RV) diastolic performance in 12 healthy subjects (control), 25 patients with chronic pulmonary diseases (CPD) and 6 patients with chronic pulmonary thromboembolism (PTE). Flow velocity patterns were determined by the pulsed Doppler technique. The values determined included acceleration time (AT), deceleration time (DT), and the ratio of the atrial contraction wave (A) to the rapid filling wave (R) (A/R ratio) from flow velocity patterns in the RV inflow tract. DT was significantly prolonged in the CPD and PTE groups compared with the control group, indicating dysfunction during the early (middle) filling period. The prolongation was marked in those patients with pulmonary hypertension. The A/R ratio was significantly higher in the CPD and PTE groups than in the control group, indicating a decrease in RV compliance. The A/R ratio increased slightly with the increase in the end-diastolic volume index. These results suggested that the pressure overload plays an important role in RV diastolic dysfunction in patients with pulmonary disease, and that preload contributes to the dysfunction.
    Respiration 02/1995; 62(5):237-43. · 2.26 Impact Factor
  • Article: Interpretation of extravascular thermal volume of the lung in patients with chronic pulmonary diseases.
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    ABSTRACT: To understand the significance of measured extravascular thermal volume of the lung (ETVL) in chronic pulmonary diseases, we measured ETVL using the double-indicator dilution technique in 17 emphysematous patients and 15 patients with pulmonary fibrosis. The level of ETVL in emphysema is significantly correlated with parameters reflecting the severity of the disease, including FEV1.0% (r = 0.54, p < 0.05), DLCO/VA (r = 0.54, p < 0.05), PaO2 (r = 0.61, p < 0.01), and mean pulmonary artery pressure (r = -0.61, p < 0.01). In pulmonary fibrosis, a significant inverse correlation was found between ETVL and PaO2 (r = -0.64, p < 0.02), DLCO/VA (r = -0.58, p < 0.05), and %VC (r = -0.61, p < 0.02). The mean level of ETVL in both groups of patients was lower than previously reported normal values. These results suggest that ETVL may reflect the decrease in pulmonary vasculature in emphysematous patients, while it may signify a decrease of pulmonary vasculature and increased volume of pulmonary interstitial tissue surrounding the pulmonary vasculature in pulmonary fibrosis. We conclude that ETVL may represent a good estimate of the condition of the pulmonary vasculature and interstitial tissue volume in patients with chronic pulmonary diseases.
    Respiration 02/1995; 62(6):302-6. · 2.26 Impact Factor
  • Article: Monitoring of nocturnal oxygen desaturation using pulse oximeter and apnomonitor in patients with chronic pulmonary disease.
    Y Miyahara, T Naito, S Ikeda
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    ABSTRACT: The relationship between the degree of nocturnal oxygen desaturation (NOD) and pulmonary hemodynamics, pulmonary function tests, and resting awake blood gases was evaluated in patients with chronic pulmonary diseases (CPD). The severity of NOD correlated with the degree of impairment of pulmonary hemodynamics, but not with pulmonary function tests or resting awake blood gases. NOD was markedly alleviated by oxygen inhalation in CPD patients who did not develop sleep apnea.
    Respiration 02/1995; 62(6):348-52. · 2.26 Impact Factor
  • Article: Ventilatory and pulmonary vascular responses to acute hypoxia are nonuniform in healthy man.
    T Naito, Y Miyahara, S Ikeda
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    ABSTRACT: The present study was undertaken to examine the pulmonary vascular and ventilatory responses to acute hypoxia in healthy individuals. Pulmonary hemodynamics and minute ventilation (VE) were serially measured during inhalation of 13% O2 for 15 min. There was a wide variability in the pulmonary vascular response to acute hypoxia, and a significant negative correlation between the initial increase in VE after the start of hypoxia (delta VE) and the percent increase in mean pulmonary arterial pressure (r = -0.646; p < 0.01). The fall in arterial oxygen tension significantly decreased in response to an increase in delta VE. These results support the view that a blunted ventilatory response to acute hypoxic stimulation enhances alveolar hypoxia, thereby favoring the constriction of pulmonary vasculature. Thus, our results suggest that the ventilatory response to acute hypoxia plays a significant role in the pulmonary vascular response to acute hypoxia.
    Respiration 01/1995; 62(4):185-9. · 2.26 Impact Factor
  • Article: [A case of obstructive sleep apnea syndrome with increased lung water during sleep].
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    ABSTRACT: A 22-year-old man was admitted to the department of plastic surgery in our university with diagnosis of ankylosis and microgeniea. His complaints were snoring and somnolence in the daytime, so we performed a Respigraph (Chest) that showed obstructive apnea during sleep. We diagnosed obstructive sleep apnea syndrome. So we observed pulmonary circulation and measured lung water using the double indicator dilution method (Nihon Koden, MTV-1100) during sleep. During the period of apnea, arterial oxygen pressure and mixed venous saturation decreased, reversely, mean pulmonary arterial pressure rose, lung water (ETV) and central blood volume increased. We considered that the increase of lung water during sleep apnea is caused by hemodynamic change due to hypoxia and increase of venous return. After operation, the value of blood gas assay and apnea index were improved.
    Kokyu to junkan. Respiration & circulation 01/1994; 41(12):1197-200.
  • Article: [A case of congenital sinus of Valsalva-right ventricule fistula].
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    ABSTRACT: A 58-year-Old male was admitted to our hospital because of heart murmur. This heart murmur had been first noticed when the patient was 7 years old, but he had no other symptoms. Color Doppler echocardiography and aortography showed that there was no deformity in the sinus of the Valsalva or in the connection to the right ventricle. Data of cardiac catheterization revealed that the shunt rate was 57% and Qp/Qs was 2.35. He was diagnosed as having congenital fistula of the Valsalva sinus to the right ventricle and an operation was recommended.
    Kokyu to junkan. Respiration & circulation 02/1990; 38(1):83-6.

Institutions

  • 2001
    • University of Nagasaki
      • Department of Internal Medicine II
      Nagasaki-shi, Nagasaki-ken, Japan
  • 1994–2001
    • Nagasaki University
      Nagasaki-shi, Nagasaki-ken, Japan