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Biomedical subjects

M Takamiya

Publications and source records attributed to M Takamiya.

At least 73 records · Page 4Linked to original sources
PubMed1995

Scintigraphic assessment of silent myocardial ischaemia after early infarction using myocardial SPET imaging with 201Tl and 123I-MIBG.

To test the hypothesis that myocardial sympathetic denervation reflects silent myocardial ischaemia early after infarction, 12 patients with myocardial infarction but without post-infarction angina pectoris underwent single photon emission tomography (SPET) at rest with 201Tl and 123I-metaiodobenzylguanidine (MIBG) shortly after and 3 months after infarction. Short-axis SPET images at the basal, mid-ventricular and apical portions of the left ventricle were selected, and each short-axis image was divided into eight segments. Tracer uptake in each of the 24 segments was scored using a 4-point scale. The total score in each segment was calculated as the defect score for each image, and the difference between the total defect score for the 201Tl and 123I-MIBG images was calculated as the delta defect score. All 12 patients underwent exercise stress 201Tl scintigraphy 1 month after infarction, and they were divided into two groups: those patients with (Group A, n = 7) and those patients without (Group B, n = 5) transient perfusion defects in the peri-infarcted region without chest pain. For the 123I-MIBG defect score, a marked reduction at 3 months was observed in Group A (24 +/- 12 vs 13 +/- 6; P < 0.01), whereas the defect score remained unchanged in Group B (25 +/- 7 vs 23 +/- 8; N.S.). The delta defect score was significantly reduced in Group A (10 +/- 5 vs 6 +/- 4; P < 0.05), whereas it remained unchanged in Group B. The 123I-MIBG defect score early after infarction was higher than the exercise-induced 201Tl defect score (24 +/- 12 vs 20 +/- 9; P < 0.01), whereas at 3 months post-infarction it was lower than the exercise-induced 201Tl defect score (13 +/- 6 vs 20 +/- 9; P < 0.05). Moreover, effort chest pain during daily activities was noted in 5 of the 7 (71%) patients in Group A within 3 months post-infarction. The results of this study suggest that viable but denervated myocardium (mismatched 123I-MIBG defects) is present in peri-infarcted regions, and that myocardial sensory nervous disturbance, which may co-exist with sympathetic nervous denervation, may induce silent myocardial ischaemia in patients with myocardial infarction.

3-Iodobenzylguanidine↗
PubMed1995

Predicting the growth of aortic aneurysms: a comparison of linear vs exponential models.

The aim of the present study was to determine whether the growth curve of aortic aneurysms had a predictable pattern, specifically whether the growth pattern was better defined by a linear or exponential rate of growth. A twelve-year retrospective review was undertaken. The authors studied 59 patients with aortic aneurysm who have been followed up nonoperatively for more than three years with sequential computed tomographic (CT) scans. There was a total of 74 aortic aneurysms (thoracic aortic aneurysm [TAA]: 30, abdominal aortic aneurysm [AAA]: 44). The diameter of the aortic aneurysm was normalized by dividing by the initial diameter. Exponential (y = A exp [Bt]) and linear (y = C+Dt) regression curves of growth of aneurysmal diameters were calculated, where y is the normalized diameter and t is the time after first CT examination in months. In regression analysis, the values fit well to the exponential growth curves, giving high regression coefficients. Exponential regression equations of TAA and AAA were y = 1.0192 exp (0.0032t), r = 0.720 and y = 1.0129 exp (0.0045t), r = 0.789, respectively. The results in favor of the exponential curve analysis were slightly higher than those favoring the linear curve. This is the first study that showed the growth curves of aortic aneurysms. Aortic aneurysms may grow exponentially rather than linearly with time, and the growth curves might be useful for estimating the natural history or predicting the timing of surgery.

Adult↗
PubMed1995

Perfusion lung scanning before and after percutaneous transvenous mitral commissurotomy--early estimation of lung congestion relief.

Percutaneous transvenous mitral commissurotomy (PTMC) has recently been used to treat mitral stenosis. The aim of this study was to evaluate the usefulness of radionuclide perfusion lung scanning in assessing the effect of PTMC on the relief of lung congestion. We studied 30 patients (7 males and 23 females, mean age 55 years). Perfusion lung scannings were performed within 1 week before and after PTMC. We calculated the ratio of activity in the upper quarter to that in the lower quarter of the right lung (U/L) as an index of lung congestion. After PTMC, the mean mitral valve area increased from 1.1 +/- 0.3 to 1.9 +/- 0.4 cm2, the mean left atrial pressure decreased from 14.8 +/- 6.3 to 9.1 +/- 3.5 mmHg, the mean pulmonary artery pressure decreased from 22.7 +/- 8.6 to 17.4 +/- 6.3 mmHg, and the U/L ratio decreased significantly from 0.89 +/- 0.40 to 0.68 +/- 0.24 (p < 0.0001). The U/L ratio showed greater improvement (4.5%) in patients whose NYHA class improved (n = 19) than in those whose NYHA class did not improve after PTMC. The U/L ratio was closely related to mitral valve area, and left atrial and pulmonary artery pressures. The change in the U/L ration before and after PTMC also reflected symptomatic improvement. In conclusion, U/L ratios obtained from perfusion lung scannings before and after PTMC reflect mitral valve area and pressures, and can be used to assess lung congestion relief after PTMC.

Adult↗
PubMed1995

[Characteristics of regional sympathetic dysfunction in acutely ischemic myocardium assessed by 123I-metaiodobenzylguanidine imaging: impairment of myocardial norepinephrine uptake or retention].

To characterize regional cardiac sympathetic dysfunction due to myocardial ischemia, we examined 123I-metaiodobenzylguanidine (MIBG) myocardial distribution of initial 15-min and 4-hr delayed SPECT images in 14 patients with recent myocardial infarction (MI), 25 patients with vasospastic angina which was angiographically proven with elgonovine maleate (Gp VSAP) and 16 patients with chest pain syndrome and normal CAG findings (GpCP). In those with MI, the study was serially done at 2 weeks after (Gp MI-1) and at 3 months after the onset of MI (Gp MI-2). We estimated regional tracer uptake in 20 segments of tomographic images by using a 4-point scoring system (0 = normal, 1 = mild, 2 = moderate, 3 = severe reduction) and calculated the total defect score (IDS). In all patients with MI, the area of reduced MIBG uptake was more extensive than the 201Tl perfusion defect in the acute stage (Gp MI-1) indicating the presence of viable but denervated myocardial tissue. Also, the MIBG defect was persistently observed from initial (TDS: 24 +/- 13) to delayed imaging (TDS: 26 +/- 12). However, in the chronic stage (Gp MI-2), the initial MIBG uptake improved (TDS: 18 +/- 9) but the delayed uptake remained almost the same (TDS: 22 +/- 10) indicating high washout of MIBG from the ischemic myocardium. Fourteen in Gp VSAP and 14 in Gp CP showed the regional MIBG defect in the delayed image more extensively than in the initial image indicating high washout of MIBG in the involved myocardial regions. These results suggest that neuronal uptake of MIBG is impaired in the acute stage of MI although neuronal retention of MIBG is predominantly impaired in the chronic stage of MI or in Gps VSAP and CP.

3-Iodobenzylguanidine↗
PubMed1995

[Feasibility of the left ventricular volume measurement by acoustic quantification method: comparison with ultrafast computed tomography].

Acoustic quantification (AQ: the real-time automated boundary detection system) allows instantaneous measurement of cardiac chamber volumes. The feasibility of this method was evaluated by comparing the left ventricular (LV) volumes obtained with AQ to those derived from ultrafast computed tomography (UFCT), which enables accurate measurements of LV volumes even in the presence of LV asynergy, in 23 patients (8 with ischemic heart disease, 5 with cardiomyopathy, 3 with valvular heart disease). Both LV end-diastolic and end-systolic volumes obtained with the AQ method were in good agreement with those obtained with UFCT (y = 1.04 x - 16.9, r = 0.95; y = 0.87x + 15.7, r = 0.91; respectively). AQ was reliable even in the presence of LV asynergy. Interobserver variability for the AQ measurement was 10.2%. AQ provides a new, clinically useful method for real-time accurate estimation of the left ventricular volume.

Feasibility Studies↗
PubMed1995

[Detection of myocardial 123I-BMIPP distribution abnormality in patients with ischemic heart disease based on normal data file in bull's-eye polar map].

Visual interpretation of 123I-BMIPP (BMIPP) myocardial images has difficulties in detecting mild reduction in tracer uptake. We studied the significance of the objective assessment of myocardial BMIPP maldistributions at rest by using a Bull's-eye map and its normal data file for detecting ischemic heart disease. Twenty nine patients, 15 with prior myocardial infarction and 14 with effort angina were studied. The initial 15-min BMIPP image was evaluated by visual analysis and by generating the extent Bull's-eye map which exhibits regions with reduced % uptake under mean-2SD of 10 normal controls. The sensitivity for determining coronary lesions in non-infarcted myocardial regions with the extent map was superior to that with visual analysis (67% vs. 33%). In the regions supplied by the stenotic coronary artery, those which showed visually negative but positive in the map and which showed positive in both had higher incidence of wall motion abnormalities and severe coronary stenosis than those with normal findings in both. These results suggest that the objective assessment based on the normal data file in a Bull's-eye polar map is clinically important for improving the limitation of the visual interpretation in 123I-BMIPP imaging.

Adult↗
PubMed1995

[Usefulness of palliative care for the patients with recurrent gastric cancer by home-IVH].

Depending upon the type of cancer involved, the period of the end stage varies greatly, and with it decreases the quality of life (QOL). In gastric cancer, for example, the terminal stage is usually short and the QOL diminishes abruptly. Thus, it takes time keeping this decrease in QOL to minimum, despite the complications, so that the patient's last days will be even somewhat more acceptable. Improvement in QOL for the patient who cannot eat due to recurrent gastric cancer can be effectively achieved by alleviation through IVH. With this in mind, the conditions consonant with the application of home IVH are as follows: 1) The patient's pain can be kept under control at home. 2) The patient wishes to remain. 3)There is sufficient human support at home. The caretakers in the family, and especially the key person(s) must exert much effort and labor and they need rest as well. Home medical care in the terminal stage presupposes a social environment involving day care, short stay, and hospice nursing facilities of all kinds. At present, public services of this kind differ with the community, much remains uninformed to public, and clinic-hospital networking will be needed more than ever. In this difficult situation, the home-care medical services provided by the private sector are effective. These services are only for the short term, of course, and there will be a financial problem. Various measures (tax deduction, public assistance) must be considered to support the patients and caretakers.

Adult↗
PubMed1994

Diastolic suction in the human ventricle: observation during balloon mitral valvuloplasty with a single balloon.

Diastolic suction has been demonstrated experimentally as a ventricular negative pressure when the ventricle is allowed to relax completely in the absence of filling, but it has not been extensively studied in the in vivo human heart. In balloon mitral valvuloplasty with a single balloon, the mitral orifice is occluded and inflow is considered to be completely obstructed during a balloon inflation. To demonstrate diastolic suction in the human ventricle, we measured left ventricular pressure during valvuloplasty with a high-fidelity catheter tip manometer in 17 patients. Left ventricular pressure fell below zero during a balloon inflation in all patients (-2 to -12 mm Hg). The peak negative diastolic pressure showed significant correlations with end-systolic volume index (r = 0.53, p = 0.03) and with the ejection fraction (r = 0.80, p = 0.0001). Thus diastolic suction was demonstrated in the human beating heart, and the sucking effect was potent in the heart with small end-systolic volume and high-ejection fraction.

Adult↗
PubMed1994

Myocardial involvement in patients with sarcoidosis. An analysis of 75 patients.

The authors studied 75 nonselected patients (30 men and 45 women; mean age 48 years) with sarcoidosis retrospectively to assess the applicability of nuclear examinations for detecting myocardial involvement. All patients were studied with Tl-201 myocardial perfusion scan (TMPS), Ga-67 myocardial scan (GMS), and left ventricular ejection fraction (LVEF) using ECG-gated radionuclide ventriculography. The positive GMS group had a significantly higher occurrence of abnormality on TMPS (100%) than the negative GMS group (41%). Patients with TMPS abnormality and positive GMS showed significantly lower LVEF (36.3%) than those of normal perfusion or negative GMS. When LVEF decreased, occurrences of TMPS abnormality and positive GMS increased. The authors demonstrate that in patients with sarcoidosis LVEF was closely related to TMPS and GMS, and LVEF reflected the progression of sarcoid heart disease and can be considered a reliable indicator of cardiac function. Patients with sarcoidosis with TMPS abnormality and positive GMS should be thought to have myocardial sarcoidosis and their cardiac functions can be assessed by ECG-gated radionuclide ventriculography, while the remaining patients should be examined with TMPS and GMS periodically for detection of myocardial involvement.

Adult↗
PubMed1994

Clinical studies on the sites of production and clearance of circulating adrenomedullin in human subjects.

Adrenomedullin is a novel hypotensive peptide, newly discovered in pheochromocytoma. Because immunoreactive adrenomedullin is present in human plasma, adrenomedullin may play a role in regulating blood pressure. A recent report showed that human adrenomedullin mRNA is expressed not only in pheochromocytoma but also in the normal adrenal medulla, kidney, lung, and ventricle. However, whether or not these organs actually release adrenomedullin into the circulation remains unknown. To investigate the sites of production and degradation of adrenomedullin in human subjects, we obtained blood samples from various sites and measured immunoreactive adrenomedullin concentrations. In study 1, blood samples were obtained from the infrarenal inferior vena cava, suprarenal inferior vena cava, superior vena cava, right atrium, right ventricle, pulmonary artery, pulmonary capillary, left ventricle, and aorta during cardiac catheterization in 15 patients with ischemic heart disease (67 +/- 10 years). In study 2, blood samples were taken from the infrarenal inferior vena cava, suprarenal inferior vena cava, right and left renal veins, and left adrenal vein in 5 hypertensive patients (42 +/- 14 years) suspected of having renovascular hypertension. In study 3, peripheral venous blood samples were obtained in 2 patients (males, 45 and 36 years old) with pheochromocytoma at rest and during hypertensive attacks. Plasma adrenomedullin concentrations were measured by a newly developed radioimmunoassay. In study 1, there were no significant differences in plasma adrenomedullin concentrations in various sites of the right-side circulation. There was no step-up of plasma adrenomedullin levels in the coronary sinus. However, the plasma concentration of adrenomedullin in aorta was slightly but significantly lower than in pulmonary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1994

[A case of inflammatory abdominal aortic aneurysm with associated inferior vena caval and bilateral ureteral obstruction].

One year ago, a 48-year-old man complained of dyspnea, and was diagnosed as mitral valve regurgitation and aortic dissection. He underwent mitral valve replacement and aortic arch grafting. He was also pointed out to have an inflammatory aortic aneurysm (IAAA) in the infrarenal abdominal aorta, but did not undergo surgery. At this admission, he had lumbago and low grade fever probably due to deterioration of the IAAA. On the preoperative radionuclide studies, inferior vena caval obstruction and bilateral ureteral obstruction or severe stenosis were demonstrated by 99mTc-MAA venography and 123I-OIH renogram, respectively. 67Ga scan showed faint abnormal accumulation at the IAAA. He underwent surgery. IAAA had a thick wall in white and hard fibrotic tissue adhered closely to duodenum, jejunum, inferior vena cava and bilateral ureters. After surgery, his renal function was improved. In this case, radionuclide studies were useful for detecting the inferior vena caval obstruction, assessing renal function and inflammatory activity.

Aneurysm, Infected↗