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M Takamiya

Publications and source records attributed to M Takamiya.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Detectability of diagonal branch disease with other branch lesions by 201TlCl exercised myocardial scintigraphy].

The detectability of coronary diagonal (Dx) branch disease in 24 patients (16 with myocardial infarction, 8 with angina pectoris; mean age of 56) with other branch (left anterior descending branch [LAD], left circumferential branch [LCX], or right coronary artery [RCA]) diseases was reviewed with 201TlCl exercised myocardial planar and SPECT images. In Dx branch disease with LAD #7 lesion (n = 10), Dx perfusion abnormality was detected in planar and SPECT images in 3 (30%) and 8 patients (80%), respectively. In Dx branch disease with LCX lesion (n = 7), Dx perfusion abnormality was detected in planar and SPECT images in 3 (43%) and 4 patients (57%), respectively. In Dx branch disease with RCA lesion (n = 7), Dx perfusion abnormality was detected in only 1 (14%) and 2 patients (29%), respectively. In conclusion, SPECT is a useful modality for detecting Dx branch disease, but it is sometimes hard to detect Dx branch disease with LCX and RCA lesions.

Coronary Disease↗
PubMed1993

Species specificity of pharmacological characteristics of CCK-B receptors.

Novel CCK-B receptor antagonists, tetronothiodin and L-156,586, showed different affinities for CCK-B receptors in brain membranes from human, rat, guinea pig and mouse. [125I]CCK-8 bound to these membranes with a similar affinity. However, tetronothiodin was most potent in rat (IC50 = 3.6 nM), followed by guinea pig (96 nM), human (210 nM) and mouse (280 nM). L-156,586 bound with highest affinity to membranes from guinea pig (11 nM), and with lowest affinity to membranes from mouse (220 nM). These results suggest the existence of species specificity of CCK-B receptors, and that these two compounds are useful tools for discrimination between these receptors.

Aged↗
PubMed1993

[Growth rates of aortic aneurysms as a risk factor in rupture: an evaluation with CT].

There is a lack of information on the rates of growth of aortic aneurysms. In the present study, the growth rates and survival rates of thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with aortic aneurysm managed nonoperatively have been followed more than 6 months with sequential X-ray computed tomography. The number of aneurysms was 211 (thoracic aortic aneurysm: 82, abdominal aortic aneurysm: 129). The growth rate of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/year, respectively. Aneurysms at the aortic arch (n = 34) grow at a higher average rate (0.56 cm/year) than aneurysms arising at other levels (p < 0.05). The survival rates showed the tendency that the higher the growth rate, the worse the survival rate. The survival rate of aortic arch aneurysm was significantly decreased when the growth rate was higher than the mean value. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with computed tomographic examination of size.

Adult↗
PubMed1993

[Detection of myocardial fatty components with ultrafast CT].

Intramyocardial fatty components are sometimes depicted by CT of the thorax. However, no studies have investigated the distribution, frequency and cause of these components by using statistical analysis. Three hundred forty-five patients with various cardiac diseases were examined with an ultrafast CT scanner, and intramyocardial fatty components were detected in 15 (4.3%) of them. The frequency of intramyocardial fatty components in each disease was as follows: 6% in ischemic heart disease, 7% in Kawasaki disease, 11% in hypertrophic cardiomyopathy (HCM), 18% in dilated cardiomyopathy (DCM) and 33% in arrhythmogenic right ventricular dysplasia (ARVD). Except for patients with HCM, the segments of the ventricles, where the fatty components were detected, agreed well with the segments with asynergy in left ventriculography and/or the segments with perfusion defect in T1 myocardial scintigraphy. Thus, ischemic fatty degeneration was considered to be a main factor in the production of intramyocardial fatty components in these diseases. The focus of arrhythmia was sometimes detected in the segments with intramyocardial fatty components in DCM and ARVD cases. It is suspected that intramyocardial fatty components sometimes produce arrhythmia in these diseases.

Adipose Tissue↗
PubMed1993

[Detection of myocardial damage in patients with dilated cardiomyopathy using ultrafast CT].

The myocardial characteristics of DCM patients were investigated by ultrafast CT (UFCT), left ventriculography (LVG) and T1 myocardial scintigraphy (SCINTI). Late enhancement, focal wall thinning and intramyocardial fatty components were detected as focal abnormal findings by UFCT. The regions of asynergy detected by LVG and perfusion defect detected by SCINTI were well correlated with those of focal abnormal findings detected by UFCT. There were significant differences between patients with and without focal abnormal findings, in ejection fraction and end-diastolic pressure of left ventricle and the incidence of ventricular arrhythmia. It is possible that these focal abnormal findings represented focal ischemic myocardial damage in DCM patients. DCM patients were divided into two different functional groups by UFCT findings.

Adolescent↗
PubMed1993

Magnetic resonance imaging of pericardial malignant mesothelioma.

Magnetic resonance imaging of pericardial malignant mesothelioma in two patients is reported. Magnetic resonance imaging clearly depicted the tumor location and expansion, and was useful in delineating the anatomic extent of pericardial malignant mesothelioma.

Adult↗
PubMed1993

Medium-term results of percutaneous transluminal balloon aortic valvuloplasty with Inoue balloon catheter for congenital aortic stenosis.

Although percutaneous transluminal balloon aortic valvuloplasty (PTAV) has been performed for congenital aortic stenosis in infants and children for several years, its efficacy and the associated aortic regurgitation (AR) have not been widely discussed. Percutaneous transluminal balloon aortic valvuloplasty using an Inoue balloon catheter was performed for congenital aortic stenosis in 12 patients (4-16 years old) in this study. The systolic aortic valve pressure gradient ranged from 42 to 111 mmHg before PTAV and became < 50 mmHg immediately after PTAV in 10 cases (83%). Eight of these 10 patients had no increase in the gradient during subsequent observation for a period of 9-40 months. Aortic regurgitation increased immediately after PTAV in nine cases (75%). It increased from grade 1 to grade 2 in eight cases and from grade 1 to grade 3 in one patient; no significant enlargement of the left ventricular end-diastolic diameter and no significant change in the left ventricular end-diastolic pressure (LVEDP) or the cardiac index was observed during follow-up in these patients. There was a correlation between the diameter of the balloon and efficacy; an appropriate diameter was considered to be about 90% of the aortic annular diameter. Changes in the hemodynamic parameter after PTAV with an Inoue balloon were small in most patients and this procedure is considered to be a treatment that should be attempted prior to surgery for congenital aortic stenosis.

Adolescent↗
PubMed1993

Arrhythmogenic right ventricular dysplasia: evaluation with electron-beam CT.

The authors evaluated four cases of arrhythmogenic right ventricular dysplasia (ARVD) with electron-beam computed tomography (CT). Except for magnetic resonance imaging, non-invasive imaging techniques such as two-dimensional echocardiography and radionuclide angiography cannot always depict the abnormal morphology of the right ventricle. Definite diagnosis of ARVD requires the use of invasive cardiac cineangiography. Proper identification of right ventricular involvement in ARVD with CT helps in the diagnosis. Volume-mode CT clearly depicted an enlarged right ventricle with a scalloped surface of the free wall, conspicuous trabeculations with low attenuation, and abundant epicardial adipose tissue, which are characteristics of ARVD. Cinemode CT revealed reduced right ventricle function and abnormal wall motion. The authors propose that millisecond-order, electron-beam CT is a suitable noninvasive examination for evaluating the morphologic characteristics of the right ventricle and its function in ARVD.

Adult↗
PubMed1993

Detection of postural cerebral hypoperfusion with technetium-99m-HMPAO brain SPECT in patients with cerebrovascular disease.

Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.

Aged↗
PubMed1992

Tetronothiodin, a novel CCKB receptor ligand, antagonizes cholecystokinin-induced Ca2+ mobilization in a pituitary cell line.

We found a novel nonpeptide CCKB receptor antagonist, tetronothiodin (Ro 09-1468), in the culture broth of Streptomyces sp. NR0489. The structure of the compound (C31O8H38S), which has a 19-membered ring with an alpha-acyltetronic acid and tetrahydrothiophene moiety, is completely different from that of any known CCK receptor antagonist. Tetronothiodin inhibited [125I]CCK-8 binding to rat brain CCKB receptors with an IC50 of 3.6 nM, whereas it showed only weak affinity for rat CCKA receptors (IC50 = 70 microM). As demonstrated autoradiographically, tetronothiodin concentration dependently inhibited [125I]CCK-8 binding to CCKB receptors in rat forebrain slices. The effects of tetronothiodin on cytosolic Ca2+ concentrations in GH3 cells, a rat anterior pituitary tumor cell line, were investigated with the fura-2 method. Tetronothiodin inhibited CCK-8-induced Ca2+ mobilization without affecting basal cytosolic Ca2+ concentrations. In conclusion, tetronothiodin is a new, potent and highly selective CCKB receptor antagonist. It is a useful tool for investigating the pharmacological and physiological roles of CCKB receptors.

Animals↗
PubMed1992

[Echocardiography-guided transseptal left atrial puncture: a safe approach to percutaneous transvenous mitral commissurotomy].

Transseptal left atrial puncture has generally been carried out under fluoroscopic control. In our experience, cardiac tamponade occurred in 3 of 83 cases during transseptal puncture for percutaneous transvenous mitral commissurotomy (PTMC) and percutaneous transvenous aortic valvuloplasty (PTAV). We tried to perform the puncture under simultaneous fluoroscopic and 2DE guidance to decrease the rate of complications. As a result, no complication has occurred in 55 cases. Furthermore, 2DE indicated that directing the puncture needle towards 4 or 5 o'clock was inappropriate, but that 3 o'clock was an appropriate direction for puncture of the fossa ovalis of a left atrium dilated because of mitral stenosis. In conclusion, transseptal left atrial puncture can safely and easily be carried out under a combination of fluoroscopic and 2DE guidance, as this procedure displays the correct position and direction of the needle tip for interatrial septal puncture.

Adolescent↗
PubMed1992

[Growth rate of abdominal aortic aneurysms as measured by Computerized tomography].

To evaluate the growth rate of abdominal aortic aneurysms, sequential computed tomography (CT) examinations were performed on 125 nonoperated patients (M/F 101/24, mean age 67 +/- 8 years, 129 lesions) at intervals of at least 6 months. Growth rates of aneurysms were obtained by subtracting the first from the last diameter and adjusting for examination interval. Mean growth rate was 0.28 +/- 0.26 cm/year. Aneurysms with an initial diameter exceeding 4 or 5 cm showed significantly faster growth than smaller aneurysms. There was no significant correlation between growth rate and atherosclerogenic factors, but systolic blood pressure was significantly higher in patients whose aneurysms ruptured. Our study showed quantitatively that aneurysms with a large diameter have a rapid growth rate, the growth rate of infrarenal aneurysms is significantly faster than that of suprarenal aneurysms, and blood pressure control is important to prevent rupture.

Adult↗
PubMed1992

Evaluation of the susceptibility effect on gradient echo phase images in vivo: a sequential study of intracerebral hematoma.

Susceptibility effect of intracerebral hematoma was estimated on the phase images of gradient echo (GrE). Thirty-five hematomas were studied 3 hr to 5 yr after the onset, a total of 72 times with use of phase and magnitude images of GrE, as well as T1-, T2-, and density-weighted spin-echo (SE) images at 1.5 T. On the basis of the theory of electromagnetism, phase shift to hematoma was calculated for simplified models with concentric distribution of paramagnetic susceptibility. All hematomas were well visualized by the phase images, the pattern of which changed sequentially. The distribution of paramagnetic susceptibility could be estimated by correlating the observed phase shifts with the calculated one. SE images were necessary to presume the type of magnetic substances. A probable hypothesis of the evolution of intracerebral hematoma is proposed.

Adult↗
PubMed1992

Quantitative assessment of myocardial enhancement with iodinated contrast medium in patients with ischemic heart disease by using ultrafast x-ray computed tomography.

BACKGROUND AND RATIONALE: The authors report the quantitation of myocardial enhancement using iodinated contrast medium in patients with ischemic heart disease. Twenty-eight patients with chronic ischemic heart disease and 11 controls were examined by ultrafast computed tomography (CT) using 100-msecond scans. METHODS: The authors analyzed M/L (ratio of post-contrast incremental increases in the left ventricular myocardial and luminal CT number) in early and late phases after contrast injection. RESULTS: In controls, mean values of early and late M/L were 30% and 51%, respectively. In infarcted or severely ischemic segments, early M/Ls (19%, 16%) were significantly small (P less than .001), whereas late M/Ls (90%, 63%) were higher (P less than .001, .01) than controls. Segments with infarction or severe ischemia were differentiated from mild or nonsignificant ischemia by using this parameter (sensitivity, 99%; specificity, 88%). CONCLUSIONS: M/L is useful for detection of the ischemic myocardium.

Contrast Media↗
PubMed1992

RelB, a new Rel family transcription activator that can interact with p50-NF-kappa B.

We have identified a serum-inducible gene, relB, which encodes a protein of 558 amino acids containing a region with high similarity to c-Rel and other members of the Rel family. Transcriptional activation analysis of GAL4-RelB fusion proteins in yeast cells reveals that RelB contains in its C-terminal 180 amino acids a transcriptional activation domain. The N-terminal part including the region of similarity with the Rel family shows no detectable transcriptional activity. RelB does not bind with high affinity to NF-kappa B sites, but heterodimers between RelB and p50-NF-kappa B do bind to different NF-kappa B-binding sites with a similar affinity to that shown by p50-NF-kappa B homodimers. However, RelB/p50-NF-kappa B heterodimers, in contrast to p50-NF-kappa B homodimers, transactivate transcription of a promoter containing a kappa B-binding site.

3T3 Cells↗
PubMed1992

Type A aortic dissection: evaluation with ultrafast CT.

The authors examined 17 patients with type A aortic dissection with ultrafast computed tomography (CT). Forty sections with 1-cm intervals, from the aortic arch to the aortic bifurcation, were scanned serially without breath holding within only 74 seconds. Except for two thrombosed dissections, all intimal flaps in the ascending aorta were demonstrated, and 14 (93%) of the 15 surgically proved intimal tears were depicted. An intimal tear in the aortic arch was missed. Since conventional scanning tends not to depict type A aortic dissection, millisecond-order ultrafast CT scanning has the potential to become the modality of choice for imaging of aortic dissection.

Adult↗
PubMed1992

Aortic aneurysms: growth rates measured with CT.

Because of a lack of information about the rates of growth of aortic aneurysms, such rates in thoracic and abdominal aortic aneurysms were determined. One hundred seventy-one patients with atherosclerotic aortic aneurysm managed nonoperatively were followed up for more than 6 months with sequential computed tomography (CT). There were 211 aneurysms (thoracic aortic, 82; abdominal aortic, 129). The growth rates of thoracic and abdominal aortic aneurysms were 0.42 and 0.28 cm/y, respectively. Aneurysms at the aortic arch (n = 34) grew at a faster average rate (0.56 cm/y) than aneurysms arising at other levels, even when the rate was corrected for the initial diameter. It is recommended that thoracic aortic aneurysms, especially aortic arch aneurysms, be followed frequently with CT examination of size.

Adult↗