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Biomedical subjects

K Tabuchi

Publications and source records attributed to K Tabuchi.

At least 91 records · Page 5Linked to original sources
PubMed1996

The cytocidal activity of OK-432-activated mononuclear cells against human glioma cells is partly mediated through the Fas ligand/Fas system.

We have been applying an adoptive immunotherapy protocol to patients with malignant brain tumors using OK-432-activated peripheral blood mononuclear cells (OK-MCs). In order to elucidate the mechanism of OK-MCs' cytotoxicity, we examined the expression of Fas ligand mRNA in OK-MCs and the cytocidal activity of these cells against a human glioma cell line, T98G which expresses a high level of Fas. The expression of Fas ligand mRNA was low in non-treated peripheral blood mononuclear cells and was elevated by treatment with OK-432, irrespective of the dose employed. Apoptosis of T98G cells induced by OK-MCs was unequivocally inhibited by the pretreatment of T98 G cells with ZB4 monoclonal antibody, which binds to Fas and blocks the binding of Fas ligand to Fas. These data indicate that the cytotoxic activity of OK-MCs via apoptosis seems to be at least partly mediated by the Fas ligand/Fas system. Adoptive immunotherapy using the Fas ligand/Fas system could be a new treatment modality for human malignant brain tumors.

Adjuvants, Immunologic↗
PubMed1996

[Two cases of breast cancer detected by 99mTc-tetrofosmin myocardial scintigraphy].

Breast cancer ranks the second position among the cancer of women in Japan. We report two cases of breast cancer detected by 99mTc-tetrofosmin. First case was 51 years old female with breast cancer (invasive papillotubular carcinoma) and dextrocardia. She received 99mTc-tetrofosmin myocardial scintigraphy to evaluate dextrocardia and suspicious coronary artery disease. A planar image of 99mTc-tetrofosmin myocardial scintigraphy showed myocardium at the right side, gall bladder at the left lower side and abnormal uptake on the left chest wall. Transaxial images of 99mTc-tetrofosmin myocardial SPECT showed myocardium at the right side and abnormal uptake on the left chest wall. Second case was 78 years old female with breast cancer (intracystic papillary carcinoma) and arrhythmia. 99mTc-tetrofosmin myocardial scintigraphy was performed to evaluate arrhythmia and suspicious coronary artery disease. A planar image of 99mTc-tetrofosmin myocardial scintigraphy shows hot nodule at the lateral side of the myocardium. Transaxial images of 99mTc-tetrofosmin myocardial SPECT showed abnormal uptake at the left lateral side on the chest wall. Both cases appeared illed foci as abnormal uptake with 99mTc-tetrofosmin scintigraphy, although histological diagnosis was different. We conclude that 99mTc-tetrofosmin scintigraphy is helpful for evaluating breast cancer.

Aged↗
PubMed1996

[Expression of apoptosis-related gene products in human brain tumors and apoptosis-inducing therapy].

To elucidate the mechanism of apoptosis in brain tumors, we analyzed the expression of apoptosis-related gene products in cultured glioma cells and biopsied brain tumor specimens. Fas, Bcl-2 family (Bcl-2, Bcl-x and Bax) and ICE family (ICE, Ich-1) were found to be involved in tumorigenesis of certain brain tumors. It was also clarified that OK-432 activated mononuclear cells could kill T98G glioblastoma cells by apoptotic mechanism through the Fas ligand/Fas system.

Apoptosis↗
PubMed1996

[Diagnostic value of high N-isopropyl-p-[123I] iodoamphetamine (IMP) uptake in brain tumors].

The diagnostic value of high N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) uptake in histologically proven intracranial tumors was evaluated in 54 patients with both early (15-35 min after injection) and delayed (4 hours) SPECT before treatment. Higher uptake in the tumor compared with normal cerebral cortex was observed in early scans in all of the five patients with primary intracranial malignant lymphoma, in two of 16 meningiomas, two of seven astrocytomas, one of three pituitary adenomas, and one central neurocytoma. Among these 11 cases all the malignant lymphomas showed persistent high uptake in delayed scans, whereas other tumors showed decreased uptake in delayed scans. This persistent high 123I-IMP uptake was characteristic of primary intracranial malignant lymphomas and was useful in the diagnosis of intracranial malignant lymphoma.

Adult↗
PubMed1996

[Detection of early cardiac dysfunction in patients with transfusion-dependent aplastic anemia and chronic iron overload in childhood. Stress-velocity relation as a sensitive index by echocardiography].

In order to detect early-stage left ventricular dysfunction, we examined a load-independent index, that is, the stress-velocity relation, by echocardiography in 13 patients with aplastic anemia including pure red cell anemia. Even when left ventricular contractility and pump function were within the normal range, its afterload had a tendency to increase in transfusion-dependent patients. The patients who had impairment of cardiac pump function died of congestive heart failure within one year after abnormal findings in stress-velocity relation were detected. Therefore, the stress-velocity relation is a sensitive, useful and noninvasive index for detecting asymptomatic myocardial dysfunction in patients with transfusion-dependency and chronic iron overload. It is necessary for these patients to undergo examinations of echocardiography at regular intervals. In case of abnormally in the stress-velocity relation, treatment for afterload mismatch and more effective chelation should be recommended to reduce the burden on the heart. Thereby, the heart is kept in better condition and the prognosis of these patients will be improved.

Adolescent↗
PubMed1996

[Indication and result of hypothermic fibrillatory arrest in coronary artery bypass grafting].

Currently, cardioplegic arrest is used for almost all coronary artery bypass grafting (CABG). However, there are some cases in which aortic occlusion or the cardioplegic infusion is not desirable. In this paper, we discussed the indications and the usefulness of hypothermic fibrillatory arrest for CABG. From April 1992 to March 1995, CABG with hypothermic fibrillatory arrest was performed in 6 patients (3.9% of total CABG cases). The reasons of employing hypothermic ventricular fibrillation were as follows; calcified ascending aorta in 2 patients, coronary aneurysm associated with Behçet's decrease in 1, revascularization to the totally obstructed branches with poor left ventricular function in 2, and collateral circulation from bronchial artery with total obstruction of left main trunk in 1. The age range was 48 to 68 years with a mean of 59.0 +/- 7.8 years. Five patients had a history of myocardial infarction and 2 of them had a left ventricular ejection function less than 0.25. Surgical procedures consisted of elective ventricular fibrillation without aortic cross-clamp, systemic hypothermia and local pericardial cooling, left atrial or pulmonary artery venting, and local vessel isolation during distal anastomosis. Average number of grafts was 2.0 +/- 0.6, and 5 left internal thoracic arteries, 2 gastroepiploic arteries and 5 saphenous vein were used. Mean duration of ventricular fibrillation was 74.0 +/- 17.5 min. Postoperative angiography confirmed all bypasses patent. Only 1 patient, whose preoperative left ventricular ejection function was 0.20, died of heart failure 5 months after the operation. All other patients survived asymptomatically. Hypothermic fibrillatory arrest is useful and reliable technique in coronary artery bypass grafting when aortic occlusion or cardioplegic arrest is not desirable.

Aged↗
PubMed1995

Detection of DNA strand breaks associated with apoptosis in human brain tumors.

Apoptosis occurs spontaneously in a wide variety of neoplasms. However, it is difficult to detect apoptotic cells in routine histological sections because the cells undergoing apoptosis die singly and are then rapidly phagocytosed. Since DNA fragmentation is an important hallmark of apoptosis, visualization of DNA strand breaks in tissue sections provides the means for readily identifying apoptotic cells in situ. We have applied an in situ DNA strand break staining procedure for the quantitative estimation of apoptotic cells in surgical specimens of 62 different brain tumours. Positively stained apoptotic cells were observed in 25 (40.3%) cases and their percentage (apoptotic index) ranged from 0.1 to 8.9. Both fragmented and condensed nuclei of apoptotic cells and apoptotic bodies were stained. In addition, we assessed the proliferative activity of each specimen by immunostaining with the MIB-1 antibody (MIB-1 index) which detects the cell cycle phase-dependent Ki-67 antigen. Brain tumours with higher MIB-1 indices showed a tendency to higher apoptotic indices. The results of this study indicate that apoptosis occurs spontaneously in various brain tumours.

Apoptosis↗
PubMed1995

Evaluation of Tl-201 SPECT for monitoring the treatment of pulmonary and mediastinal tumors.

Tl-201 single photon emission computed tomography (SPECT) was performed in 88 patients with pulmonary or mediastinal tumors in order to evaluate its usefulness for the detection of disease and for the assessment of the effect of treatment. We also examined mediastinal and hilar lymph node metastasis from lung cancer. Tl-201 SPECT showed abnormal accumulation on delayed images in all lung cancer patients with tumor diameters more than 12 mm. In the 14 operated lung cancer patients, mediastinal and hilar lymph node metastases with diameters of more than 15 mm were imaged, but one with a diameter of 9 mm was missed. The retention index (RI) was 27.52 +/- 31.58 in malignant tumors and -13.67 +/- 8.15 in benign tumors (p < 0.05). The RI was significantly lower after treatment than before treatment. The interval until tumor recurrence or reactivation tended to be longer in patients who showed a significant decrease in the RI after therapy. These findings suggest the usefulness of the RI as an index of therapeutic efficacy.

Adenocarcinoma↗
PubMed1995

Dysembryoplastic neuroepithelial tumor: report of three cases.

BACKGROUND: Dysembryoplastic neuroepithelial tumor (DNT) is one of the mixed neuronal-glial tumors that should be differentiated from low-grade gliomas. The recognition and correct diagnosis of DNT is important because this tumor is curable by excision. METHODS: We report three cases of histologically proven DNTs with various image studies performed preoperatively and describe characteristic findings of them, as well as those of previous reports. RESULTS: In our three cases, computed tomography (CT) showed a well-defined, nonenhancing hypodense area. Magnetic resonance imaging (MRI) demonstrated a cortical mass of hypointensity on T1- and of marked hyperintensity on T2-weighted images. I-123-IMP or Tc-99m-HMPAO single-photon emission computed tomography (SPECT) images showed marked hypoperfusion of the lesion. Thallium-SPECT showed no uptake. CONCLUSIONS: I-123-IMP, Tc-99m-HMPAO, and Thallium-SPECT images, as well as CT and MRI, may be helpful in distinguishing DNT from low-grade gliomas.

Adult↗
PubMed1995

Tc-99m sestamibi uptake by malignant lymphoma and slow washout.

Tc-99m sestamibi has been used to detect primary brain tumors, lung tumors, and breast cancers. The authors report a patient who had superior vena cava (SVC) syndrome and underwent Tc-99m sestamibi and Tl-201 SPECT to differentiate the tumor from thrombus in the mediastinum because of an abnormal mass lesion on a contrast enhanced CT scan. An abnormal area of increased Tc-99m sestamibi uptake in the supra azygos area was demonstrated on early and delayed SPECT imaging. The washout of tumor uptake was slow. The removed tumor was confirmed to be malignant lymphoma.

Aged↗
PubMed1995

[Properties of a hemolysin produced by group C streptococci isolated from hemolytic streptococcal infection in formosan squirrels].

The hemolysin produced by group C streptococci (GCH) has an isoelectric point (pI) of 5.6 and a molecular weight of 32,000 and shows hemolytic activity in the absence of 2-mercaptoethanol (2-ME). The hemolytic activity of GCH was compared to that of streptolysin S (SLS). These hemolysins did not differ with respect to the binding and release of hemoglobin (Hb). GCH was bound to phospholipids on the membranes of target erythrocytes, followed by the rapid released of K+ and slow Hb release after a relatively long lag time. GCH showed a lower hemolytic efficiency than SLS, reflecting the fact that these hemolysins destroy erythrocytes by slightly different mechanisms.

Animals↗
PubMed1995

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

Bacterial Typing Techniques↗
PubMed1995

Aneurysm of a persistent primitive olfactory artery. Case report.

A ruptured anterior cerebral artery (ACA) aneurysm is reported in a patient in whom an anomalous ACA arose from the internal carotid artery at the bifurcation. The aberrant artery coursed anteriorly along the ipsilateral olfactory tract and made a hairpin turn posterior to the olfactory bulb, supplying the circulation of the ACA. Persistence of the primitive olfactory artery is suggested as an embryological origin of this vascular anomaly.

Aneurysm, Ruptured↗
PubMed1995

[Clinical usefulness of dipyridamole loading 99mTc-tetrofosmin myocardial scintigraphy].

This study performed to establish the most suitable method in one-day protocol and to evaluate clinical usefulness of 99mTc-tetrofosmin myocardial scintigraphy after dipyridamole infusion. Image quality and liver overlapping of the myocardial SPECT were evaluated in 107 patients with old myocardial infarction (42 cases), angina pectoris (53 cases) and others (12 cases). Left ventricular wall motion and coronary artery stenosis were compared to myocardial uptake score in 55 patients who received cardiac catheterization. The suitable image quality was acquired in early SPECT images using 259 MBq of 99mTc-tetrofosmin. The overlapping between inferior wall and liver uptake was able to minimize over 45 minutes interval from injection of 99mTc-tetrofosmin to data acquisition. The segments of normal wall motion had no perfusion defect of the myocardial SPECT in all cases (100% (148/148)). The segments of abnormal wall motion had decreased myocardial uptake of the myocardial SPECT (77% (24/31)). The agreement between coronary artery stenosis and decreased myocardial uptake was 96% (24/25) in right coronary artery, 87% (26/30) in left anterior descending coronary artery and 83% (19/23) in left circumflex coronary artery. These data suggests that image quality of dipyridamole loading 99mTc-tetrofosmin myocardial scintigraphy. Myocardial perfusion in the 99mTc-tetrofosmin myocardial scintigraphy is good correlation to both left ventricular wall motion and coronary artery stenosis.

Adult↗
PubMed1994

Visualization of DNA double strand breaks in the gerbil hippocampal CA1 following transient ischemia.

To clarify the relationship between delayed neuronal death and apoptosis, we made an attempt to detect DNA strand breaks in the gerbil hippocampal CA1 pyramidal neurons following transient ischemia by an in situ DNA double strand breaks staining. The condensed nuclei of neurons in CA1 were occasionally seen and positively stained 3 days after ischemia. The degenerating dark neurons with condensed nuclei in CA1 markedly increased in number and were clearly stained for DNA strand breaks 5 days after ischemia, whereas normal-looking nuclei remained unstained. No neurons were stained in other hippocampal subfields and dentate gyrus. The present study strongly indicates that the CA1 pyramidal neurons die through an apoptotic process.

Animals↗
PubMed1994

[Three-dimensional CT imaging of pulmonary nodules using helical scan CT].

To evaluate the usefulness of three-dimensional (3D) imaging of pulmonary nodules from helical scan CT images, 3D reconstructions were performed in 23 patients, using a CEMAX VIPstation. These cases included 15 lung cancers, six metastatic lung cancers, an aspergilloma and a tuberculoma. The equipment used was a Toshiba CT system, the X force. Helical scan CT data were acquired using up to 20 continuous 1.5 sec rotations with an X-ray beam width of 5 mm and a couchtop movement speed of 5 mm/1.5 sec, and during a single breath-hold. Axial images were reconstructed at a section interval of 2 mm. Helical scan CT permits axial images to be reconstructed at any desired position within the scanned area, and provides images without interslice gaps caused by respiratory movement. Therefore, high-quality 3D images can be obtained from these data. Concerning the optimum threshold range of CT number of 3D reconstruction, we clarified the lower and upper limits (lower/upper), as follows: 1) Solid pulmonary nodule: (-700-(-)400/-100 HU) 2) Tumor invaded to pleura or chest wall: (-700-(-)400/-200 HU) 3) Pulmonary nodule with cavity: (-700-(-)400/50 HU) 4) Small pulmonary nodule (< 10 mm): (-750-(-)600/-100 HU) In all cases, it was possible not only to demonstrate abnormal findings three-dimensionally, but also to grasp anatomical relationships among the pulmonary nodule, bronchi, vessels and chest wall. In conclusion, it was considered that 3D CT imaging provided additional anatomical information and was very useful.

Adenocarcinoma↗