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Biomedical subjects

K Tabuchi

Publications and source records attributed to K Tabuchi.

At least 109 records · Page 6Linked to original sources
PubMed1994

Evaluation of the ventilation-perfusion ratio in lung diseases by simultaneous anterior and posterior image acquisition.

Ventilation and perfusion images were acquired during tidal breathing using 81mKr gas and 99mTc-MAA. Anterior and posterior functional images of V/Q and Q/V were simultaneously acquired in 34 subjects with various lung diseases and 6 healthy controls. Superimposed anterior and posterior images were constructed and histograms of the frequency distribution for ventilation, perfusion, and the V/Q ratio were displayed for both lungs as well as for the left and right lungs individually. Blood gas analysis and general lung function tests were also performed on the day before scintigraphy. A correlation between marked uneven distribution of V/Q and A-aDO2 was found. When the proportion of counts at V/Q < 0.67 and/or V/Q > 1.50 in the V/Q counts histogram was compared with A-aDO2, there was a significant positive correlation for anterior images (r = 0.684, p < 0.05), posterior images (r = 0.654, p < 0.05) and superimposed images (r = 0.696, p < 0.05). Superimposed images therefore showed the highest correlation. There was no correlation between the results of lung function testing and A-aDO2. Coronal SPECT images were also obtained in 15 patients and compared with the superimposed anterior and posterior planar images. There was a good correlation (r = 0.888, p < 0.001) between both the imaging methods regarding the marked uneven distribution of V/Q. Simultaneous anterior and posterior planar image acquisition reduces the examining time, is simple, and is noninvasive. The present results also suggest that it is useful for quantitative evaluation of the ventilation-perfusion ratio.

Adolescent↗
PubMed1994

Peripheral benzodiazepine stimulates secretion of growth hormone and mitochondrial proliferation in pituitary tumour GH3 cells.

High affinity receptors for peripheral benzodiazepines (PBD) are present within the pituitary gland. Whether these receptors influence cell growth, mitochondrial morphology and secretion of growth hormone was examined in pituitary tumour GH3 cells. Cells were incubated in medium with either 10% calf serum, or serum free medium, or serum free medium plus 10 nM of selective PBD ligands (PK11195 or Ro5-4864) or a central benzodiazepine ligand (clonazepam). Peripheral or central ligands had no effect on cell growth. Quantitative electron micrography, however, revealed that cells treated with PBDs had a 2.5-fold increase in the total mitochondrial area within cells, a 1.6-fold increase in the number of mitochondria, and a 2.0 to 2.7-fold increase on the number of dividing mitochondria compared to serum free controls. The activity of DNA polymerase gamma, which replicates mitochondrial DNA, was increased approximately 3 times the initial value after 6 h exposure to PBDs. The number of nucleolar organizer regions (NORs), which relate to the ultimate synthesis of cellular protein, showed a 1.4-fold increase in PBDs treated cells. Secretion of growth hormone was stimulated (240% of serum free control) by exposure to PBDs for 12 h. The central benzodiazepine ligand, clonazepam, had little effect on mitochondrial morphology or secretion of growth hormone. These findings suggest that PBD receptors may be involved in mitochondrial proliferation and may affect the secretion of pituitary hormones.

Adenoma↗
PubMed1994

[Contamination of healthy livestock with verocytotoxin producing Escherichia coli (VTEC), the first isolation from goats in Japan].

As part of the investigation on the source and route of infection with Verocytotoxin producing Escherichia coli (VTEC) in human beings, isolation of VTEC was attempted using fresh feces collected from healthy livestock (cattle, swine and goat) raised in Sagamihra, Yokohama and Hiratsuka cities from October, 1991 to March, 1992. VTEC could be isolated from 1 (1.0%) of 105 swine, 2 (3.6%) of 55 cattle and 2 (15.4%) of 13 goats. VTEC was isolated for the first time from goats in Japan. The combinations of the serotype and toxin type of the isolated strains were O116:H21 (VT2) and O163:H19 (VT2) for those isolated from the cattle, OUT:H19 (VT2vp) for that from the swine and OUT:H21 (VT1) for those from the goats. Since VTEC isolated from the cattle and goats were found to produce VT of the same serotypes as human VTEC, domestic animals were considered to be involved as a source of VTEC infection in human beings.

Animals↗
PubMed1994

Familial arteriovenous malformations of the brain--two case reports.

Familial arteriovenous malformation (AVM) of the brain is an uncommon entity. A 24-year-old female presented with sudden onset of left hemiparesis due to an AVM with a hematoma in the right frontal lobe, which was surgically removed. Her 23-year-old younger sister presented with motor aphasia and right hemiparesis due to an AVM with a hematoma in the left frontoparietal lobes, which was surgically removed. Thirty-two patients in 15 families have been described in total. The mean age of these patients was 28 years, with 15 males and 17 females. Multiple AVMs occurred in four patients (12.5%), more frequently than in non-familial cases.

Adult↗
PubMed1994

[Cerebellopontine angle lipoma with vascular anomaly: a case report].

A case was reported of cerebellopontine angle lipoma with vascular anomaly which was thought to be the remnant of fetal anastomosis of the posterior inferior cerebellar artery (PICA) and of the anterior inferior cerebellar artery (AICA). A 42 year-old man had been suffering from intermittent dizziness for a year. Worsening of dizziness after mild head trauma led him to visit a doctor who pointed out a cerebellopontine angle lesion. On admission to our hospital, neurological examination revealed no deficit. Computerized tomography (CT) scanning showed a low density mass in the right cerebellopontine angle, which was 1.5cm in diameter and showed no enhancement with intravenous contrast material. The attenuation value on CT of this lesion was--101 Hounsfield units. MRI showed a homogeneous mass, which was markedly hyperintense on T1 weighted image and proton image, isointense with chemical shift artifact on T2 weighted image and markedly hypointense on short TI IR (STIR) image. Signal characteristics on MRI were consistent with those of lipoma. Interestingly, MRI demonstrated the cranial nerves and vessels penetrating small lesion. The vertebral angiograms revealed the anastomosis of PICA and AICA with segmentally hypoplastic vertebral artery on the right side and the dilatation of the right distal AICA. Through a right suboccipital approach a yellowish mass in the right cerebellopontine angle was resected partially (about 50%). Only partial resection was possible because of the bleeding from small arteries and the tight adhesion to cranial nerves and brain stem. Histological findings of the surgical specimen were consistent with those of a lipoma. Postoperative neurological examination showed no neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Assessment of myocardial contraction and relaxation with 99mTc-tetrofosmin multi-gated myocardial SPECT].

Myocardial relaxation at the diastolic phase was not evaluated by multi-gated myocardial SPECT, although myocardial contraction at the systolic phase was studied by percent wall thickening and Bull's eye methods. We make out a myocardial volume curve and report to evaluate the myocardial relaxation using multi-gated myocardial SPECT. The study population consisted of 3 normal human subjects (3 male, 32-37 years old), 10 idiopathic cardiomyopathy, 10 coronary artery disease and 1 hypertensive heart disease combined with aortic regurgitation. All cases were injected 555 MBq of 99mTc-tetrofosmin (Amersham Healthcare Corporation) intravenously at rest. A triple detector gamma-camera (GCA-9300A, Toshiba Medical, Japan) and a data processing computer (GMS-5500A, Toshiba Medical, Japan) were used in this study. A cardiac cycle (R-R interval) was divided by 16 frames (50-80 msec per 1 frame). Eight myocardial volume curves were calculated at the anterior wall, apex and inferior wall of the vertical long axis view and were calculated at the septal wall, apex and lateral wall of the horizontal long axis view, respectively. The patterns of the myocardial volume curves were classified into 5 patterns (Normal pattern (N), Delayed Contraction pattern (DC), Delayed Relaxation pattern (DR), Mixed pattern (M) and Normal pattern with Decreased amplitude (ND)). Myocardial uptake was evaluated visually of grading into severe hypertrophy (5), hypertrophy (4), normal (3), mild hypoperfusion (2), hypoperfusion (1) and perfusion defect (0). We compared patterns of the myocardial volume curves to myocardial uptake in the same segments. It was possible to detect myocardial edge of the total 16 frames with 50-60% threshold in the normal volunteer and in patients with hypertrophic cardiomyopathy and to make a myocardial volume curve. The region of the severe myocardial perfusion defect could be detected with 20% threshold in patients with old myocardial infarction. In comparison with myocardial volume curves and myocardial uptake, 74.6% in the N pattern had a normal uptake (3), 66.7% in the ND pattern had a normal uptake (3), 61.5% in the DC pattern had a hypoperfusion segment (0, 1 or fill-in to normal uptake), 44.4% in the DR pattern had a hypertrophic segment (4, 5 or fill-in to increased uptake). The pattern of myocardial volume curve indicates myocardial contractility and relaxation in each myocardial segment.

Adult↗
PubMed1994

Induced expression and subcellular localization of the Bcl-2 protein in cultured glioma cells.

It has recently been shown that the bcl-2 gene is involved in the growth and development of certain tumors by suppressing apoptosis. To explore the possible involvement of the Bcl-2 protein in gliomas, three human glioma cell lines (T98G, A172, and U251) were examined for the presence of this protein. It could be documented by confocal laser microscopy that the Bcl-2 protein was localized mainly in mitochondria and nuclear membrane of T98G cells. Flow cytometric analysis revealed that 71-87% of the cultured glioma cells expressed the Bcl-2 protein. Treatment of U251 cells with ACNU for 24 h induced increased Bcl-2 protein expression; induction was dose dependent. Exposure of T98G and A172 cells to ACNU did not affect their Bcl-2 protein levels. Southern blot analysis revealed no chromosomal translocation in the cells studied. These findings suggest that Bcl-2 protein overexpression in glioma cells may partly contribute to tumor growth and tolerance to chemotherapeutic agents.

Blotting, Southern↗
PubMed1994

[Clipping of aneurysm arising from the posterior communicating artery itself by contralateral craniotomy: a case report].

A case of aneurysm arising from the posterior communicating artery itself clipped by contralateral frontotemporal craniotomy (pterional approach) is presented. A 65-year-old female developed sudden severe headache and chest pain in January of 1993. Neurological examination on admission revealed consciousness disturbance such as stupor and nuchal stiffness. CT-scan showed marked subarachnoid hemorrhage. She also suffered from acute myocardial ischemia and cardiac failure. Cerebral angiograms after recovery from cardiac dysfunction demonstrated three saccular aneurysms arising from the dilated right posterior communicating artery itself, the junction of the left internal carotid artery and the posterior communicating artery, and the bifurcation of the left middle cerebral artery. The left IC-PC junction aneurysm was thought to be ruptured because of its size and contour, so left frontotemporal craniotomy was undertaken. By the left pterional approach, successful clipping of all three aneurysms involving the one arising from the contralateral posterior communicating artery was achieved. The aneurysm at the posterior communicating artery itself was found to arise from the non-branching site and to project inferiorly, thus the successful clipping through the prechiasmal cistern could be performed without compromising any small perforating arteries.

Aged↗
PubMed1994

[A case of pineal teratoma with interesting radiological findings].

A rare case of mature pineal teratoma with interesting radiological findings in a 16-month-old infant is reported. The patient was referred to our clinic because of generalized convulsions. A CT scan showed marked hydrocephalus and a low density mass lesion without contrast enhancement in the pineal region. A CT cisternography demonstrated the lesion as a filling defect area on the image produced immediately after the emergent V-P shunt, and a filling area 24 hours later. The lesion was of signal intensity on T-1 weighted MR image and of high signal intensity on T-2 weighted MR image, equal to CSF intensity. These radiological findings were compatible with an arachnoid cyst in the quadrigeminal cistern, so we performed the excision of both anterior and posterior cyst walls using the occipital tentorial approach. However, the histology of the cyst wall was not compatible with that of an arachnoid cyst, showing neuroepithelial-like cell lining with positive staining for cytokeratine. The postoperative follow-up on MRI was continued for 31 months. An MRI performed 9 days after the first operation showed, compared with the gray matter, iso-signal intensity area and high signal intensity area on T-1 weighted image. At first, we thought this was because of bleeding of the pineal gland brought on by the operative maneuver. However, the mixed intensity lesion shown on T-1 weighted images gradually expanded and distorted, and finally showed the typical MR images for a teratoma. The operative findings using the occipital transtentorial approach were typical for a teratoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Arachnoid Cysts↗
PubMed1994

[Clinical evaluation of 99mTc-MAG3 renal imaging: comparison with 99mTc-DTPA, 99mTc-DMSA and 131I-OIH].

The newly developed 99mTc-labeled renal imaging agent, mercaptoacetyltriglycine (MAG3), is a tubular secreted compound. It is expected the most suitable agent to measure renal function and image urinary tract because of the excellent imaging properties and availability of 99mTc and preferred biological qualities of radiohippurates. We examined 15 patients (8 males, 7 females, mean age 55 years old) with renal and urinary tract disease. After drinking 400 ml of water, 185, 370 or 555 MBq of 99mTc-MAG3 was injected with the supine position. Dynamic scans were acquired for 20 minutes on a large field of view gamma camera (ZLC-7500 Siemens Medical Inc.) linked to a computer system (Scintipac-2400 Shimadzu Co.) in a 64 x 64 matrix. Regions of interest (ROI) were placed around each kidney. Curves of 12 seconds frame rate were generated from all two ROIs over the 20 minutes study. The time to peak count (Tmax) and time from peak count to a half count (T1/2) were calculated from the curve data. 99mTc-DTPA renal imaging was examined to the same patients with the same method like 99mTc-MAG3. The renogram of 131I-orthoiodohippurate (OIH) was performed with probe method. The excellent quality of the renal image was obtained with 185-555 MBq of 99mTc-MAG3 compared with the same dose of 99mTc-DTPA respectively. The diagnostic value of 99mTc-MAG3 renal imaging was as well as 99mTc-DMSA renal imaging. The Tmax of 99mTc-MAG3 renogram was same value of that of both 99mTc-DTPA and 131I-OIH renogram. The T1/2 of 99mTc-MAG3 renogram was significantly lower than that of 99mTc-DTPA renogram. The T1/2 of 99mTc-MAG3 renogram was slightly higher that of 131I-OIH renogram. We conclude that the renal imaging of 99mTc-MAG3 was able to acquire the most excellent image and the proper renogram pattern as same as 131I-OIH renogram.

Adult↗
PubMed1993

Development of simulation models for protein folding in a thermal annealing process--I: A simulation of BPTI folding by the pearl necklace model.

A model system is proposed to simulate the folding processes of proteins during thermal annealing. This system consists of four subsystems: (i) the pearl necklace model with isotropic inter-residue interactions; (ii) the extended pearl necklace model with anisotropic interaction potentials; (iii) molten globule phase dynamics; and (iv) final generation of the three-dimensional structure of a given protein. In this paper results obtained with the pearl necklace model are reported. This model consists of spherical elements and virtual bonds of 3.8 A in length and is intended to simulate dynamical processes at relatively high temperature where entropic terms play a dominant role. Inter-residue interactions are composed of spherical soft repulsive potentials and hydrophobic interactions inherent to respective residues. A simulation of folding processes of BPTI starting from the fully extended conformation indicated that intermediates, even at early stages of folding, are not randomly coiled but assume organized structures that resemble, to some extent, the native conformation.

Aprotinin↗
PubMed1993

Frontal lobe tumor associated with late-onset seizure and psychosis: a case report.

This is a report of a 55-year-old woman with a 6-year history of uncontrollable complex partial seizure and severe delusion. A computed tomography (CT) brain scan showed a nonenhanced low density area with an ill-defined mass located at the right frontal lobe. Magnetic resonance imaging (MRI) demonstrated an area of hyperintensity on T2-weighted images. After a tumorectomy, the patient gradually recovered from the seizures and delusion. A histological diagnosis showed a mixed oligoastrocytoma or dysembryoplastic neuroepithelial tumor (DNT). The clinical and pathological features of the tumor as well as its relation to psychosis were discussed.

Biopsy↗
PubMed1993

[Studies on hemolytic streptococcal infection: 1). Outbreak of group C hemolytic streptococcal infection in Formosan squirrels].

Between mid-October to mid-November 1992, of 500 freely-ranging Formosan and striped squirrels kept at Garden Y in the suburbs of Kanagawa Prefecture, 414 (82.8%) suddenly died one after another by bleeding from the nasal and oral cavities after developing a mild facial swelling. Isolation of microbes including viruses were carried out from the Formosan squirrels that had suddenly died. Various organs from these animals were histologically examined. 1. In bacteriological tests, beta-hemolytic streptococcal strains were isolated in a pure culture from 5 (83.3%) of 6 Formosan squirrels that had died suddenly. By serological analysis, 14 isolated strains were serotyped as group C according to the classification of Lancefield. From their biochemical characteristics, these were identified as Streptococcus equi subsp. zooepidemicus. A drug sensitivity test revealed that ABPC, PCG, SBPC, CMX and CPZ are highly sensitive against the isolates. 2. In the virological test, the viral isolation was applied for three blind passages by primary cultured kidney cells of Formosan squirrels, but no evidence of CPE was obtained. 3. At autopsy, a pathological change was detected mainly in the lungs. Histopathological examinations revealed severe hypertrophic changes of the alveolar wall in the entire pulmonary lobe. Severe congestion, hemorrhagic pneumonia, neutrophils and macrophages infiltration were observed in the hypertrophic alveolar wall. In the other cases, thrombi were observed in the branches of the pulmonary artery. Other organs demonstrated no remarkable histopathological changes. 4. Streptococcal strains were not isolated from the pharynx in all of the employees working at this garden.

Animals↗
PubMed1993

[A basic study of multi-gated single photon emission computed tomography with thallium-201].

A Multi-gated SPECT was acquired commonly in 64 x 64 matrix and 8 frames per cardiac cycle (64 x 64/8F). But it was not established that 64 x 64 matrix and 8 frames per cardiac cycle were the most suitable in multi-gated SPECT. Five normal volunteers were examined multi-gated 201Tl SPECT with 5 acquisition modes of 128 x 128 matrix/16 frames, 128 x 128/8F, 64 x 64/32F, 64 x 64/8F using multi-detector SPECT system (GCA-9300). And we calculated percent wall thickening (%WT) [%WT = (ES counts - ED counts)/ED counts] in 9 cases with 64 x 64/8F. The images quality of both 128 x 128/16F and 128 x 128/8F was not clear in compared with images of both 64 x 64/16F and 64 x 64/8F, because the end-diastolic phase of 128 x 128/16F images showed a decreased uptake of 201Tl in the antero-apical region. Although 64 x 64 (8) images had only 8 frames per cardiac cycle, we could observe systolic and diastolic phase and we could calculate %WT. The %WT (M +/- SD) of horizontal long axis images were 48 +/- 15 (sept. basal), 48 +/- 19 (sept. apical), 65 +/- 29 (apex), 49 +/- 22 (lat. apical) and 40 +/- 15 (lat. basal).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Autopsy report of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis: diagnosis with the immunoglobulin gene rearrangements analysis.

We report a case of primary CNS B-cell lymphoma indistinguishable from multiple sclerosis (MS). MRI of the head showed the spontaneous disappearance of the white matter lesions and the progressive cerebral atrophy. The brain biopsy failed to make a diagnosis of CNS lymphoma but rather suggested MS. Although the primary CNS lymphoma was suspected at autopsy, the immunohistochemical study showed the CNS-infiltrating lymphoid cells comprising both T-cells and B-cells. Analysis of the immunoglobulin and T-cell receptor gene rearrangements first provided evidence of primary CNS B-cell lymphoma.

Atrophy↗
PubMed1992

Drug resistant plasmid of Actinobacillus pleuropneumoniae isolated from swine pleuropneumonia in Thailand.

Actinobacillus pleuropneumoniae, isolated from the pneumonic lung tissue of pigs, was resistant to streptomycin, sulfadiazine and tetracycline. This isolate, TA5, possessed 2 plasmids (pTA51 = 3.7 Kb, pTA52 = 6.2 Kb); one of the plasmids (pTA52) was coded for resistance to SM and SA. Another isolate of A. pleuropneumoniae, TA8, also possessed 2 plasmids (pTA81 = 3.7 Kb, pTA82 = 4.4 Kb), with a plasmid (pTA82) coded for resistance to SM and SA. All 4 plasmids were not transmissible and small.

Actinobacillus Infections↗