Search PubMed⌕ Search

Biomedical subjects

T Ota

Publications and source records attributed to T Ota.

At least 91 records · Page 5Linked to original sources
PubMed2000

An integrated analysis and database system for full-length cDNA.

Annotation and database system of full-length cDNA sequences was developed. As the components of the system, ORF annotation system, functional annotation system based on database search results, mapping annotation system, and integrated retrieval and display system were developed. In the ORF annotation system integrated analyses using conventional tools are performed and useful retrieval interface using motif list are introduced. In the functional annotation system based on database search results, a new method that characterizes a given unknown cDNA was developed by using a profile of similarity level over words appearing in sequence database entries. In the mapping annotation system, we linked by similarity searches full-length cDNA sequences with database DNA sequences that are already mapped on chromosomes. By using these links, full-length cDNAs can be retrieved by the retrieval condition of physical mapping information. Genetic disease information mapped on the physical mapping site can also be displayed by this system. Furthermore, we constructed an integrated database system for these analyzed data, and thus enabled annotation and selection of full-length cDNAs from points of both gene function and mapping information.

Chromosome Mapping↗
PubMed1999

Motor neglect following left thalamic hemorrhage: a case report.

We present a report on a patient who developed unilateral motor neglect of the right hemibody after a left thalamic hemorrhage. He presented with pure motor neglect without aphasia, ideomotor apraxia, or unilateral spatial neglect due to a lesion in the centromedian parafascicular (CMPF) and ventrolateral (VL) nuclei of the left thalamus. Although unilateral motor neglect is usually associated with right hemispheric lesions, a left thalamic lesion may also result in isolated motor neglect.

Adult↗
PubMed1999

Decrease of metastatic ability after selection for intravasating ability in Lewis lung carcinoma (3LL) cell line.

The release of cancer cells from the primary site and penetration into blood vessels are obligatory preliminary steps for metastasis. To investigate the mechanism of such steps we isolated variant cells (designated as Int-3LL) possessing enhanced intravasating ability from Lewis lung carcinoma (3LL) cells by in vivo selection. In spite of the enhanced intravasating ability of Int-3LL, the spontaneous and experimental metastatic abilities of Int-3LL decreased significantly compared to parent cells. Such a cell line has never been reported so far. The matched pair of cell lines described in this report provides a useful system for investigating the primary steps of metastasis.

Animals↗
PubMed1999

Cross-linking of CD44 on rheumatoid synovial cells up-regulates VCAM-1.

CD44 is a ubiquitous molecule also known as hyaluronic acid or homing receptor. However, the cellular functions and its role in inflammation, for example, rheumatoid synovitis, are currently unknown. In this study, we propose a novel function for CD44. Using synovial cells from rheumatoid arthritis (RA) patients, we demonstrated that CD44 cross-linking and binding to hyaluronan augmented VCAM-1 expression and subsequently VCAM-1-mediated cell adhesion. Briefly, we found that 1) rheumatoid synovial cells highly expressed CD44; 2) cross-linking of CD44 markedly but transiently augmented VCAM-1 expression and its mRNA transcription much more than did IL-1beta and TNF-alpha; 3) hyaluronan, especially when fragmented, also up-regulated VCAM-1; 4) CD44 activated the transcription factor AP-1; and 5) the integrin-dependent adhesive function of RA synovial cells to T cells was also amplified by CD44 cross-linking. These results indicate that the adhesion of RA synovial cells to matrices such as hyaluronic acid through CD44 could up-regulate VCAM-1 expression and VCAM-1-mediated adhesion to T cells, which might in turn cause activation of T cells and synovial cells in RA synovitis. We therefore propose that such cross-talking among distinct adhesion molecules may be involved in the pathogenesis of inflammation, including RA synovitis.

Adjuvants, Immunologic↗
PubMed1999

Hydrogen peroxide-induced apoptosis mediated by p53 protein in glial cells.

It is now generally accepted that massive neuronal death due to oxidative stress is a regular feature of brains in neurodegenerative diseases. However, much less attention has been given to the death of glial cells. In this study, we examined p53-sensitive apoptosis of cells by using human glioblastoma A172 cells and p53-deficient mouse astrocytes. In human A172 cells, hydrogen peroxide (H2O2) caused cell death in a time- and concentration-dependent manner, accompanied by nucleosomal DNA fragmentation and chromatin condensation. After treatment with H2O2, p53 protein was highly expressed and protein levels of Bak, p21WAF1/CIP1 and GADD45 were also enhanced. However, the protein levels of Bcl-2 and Bax did not change. On the other hand, primary cultured astrocytes from p53-deficient mouse brain grew faster than wild-type and heterozygous astrocytes. In addition, p53-deficient astrocytes were more resistant to H2O2-induced apoptosis than wild-type and heterozygous astrocytes. These results suggest that glial proliferation and the repair of damaged DNA may be regulated by p53-induced p21WAF1/CIP1 and GADD45, and that glial apoptosis caused by oxidative stress may be mediated by p53-induced Bak.

Animals↗
PubMed1999

Effect of molecular weight, calcium stearate, and sterilization methods on the wear of ultra high molecular weight polyethylene acetabular cups in a hip joint simulator.

Orthopaedic surgeons must currently choose from several types of ultra high molecular weight polyethylene acetabular cups that differ in their material properties and in the methods used for their sterilization. Information on the wear resistance of these different cups may help in the selection process. This study included two separate tests for wear run on a hip simulator to investigate the effect of molecular weight, calcium stearate, and sterilization methods on the wear resistance of ultra high molecular weight polyethylene acetabular cups. Test 1 revealed nearly identical wear rates for acetabular cups with molecular weights in two distinct ranges, as well as for cups with molecular weights in the same range but with or without calcium stearate added. In Test 2, cups that were sterilized in air with gamma irradiation exhibited lower rates of wear than those sterilized with ethylene oxide, presumably due to the crosslinking induced by the irradiation. In addition, cups that were irradiated while packed in a partial vacuum to minimize oxygen absorbed in the surface layer initially showed lower rates of wear than those irradiated in air, with the wear rates becoming similar as wear penetrated the more oxidized surface layer and the more crosslinked subsurface region. Because these tests were run a few months after the irradiation, the potential effects of long-term oxidation of any residual free radicals in the irradiated materials could not be taken into account. After artificial aging to accelerate oxidative degradation of the materials, the wear rates could be markedly different. Analyses performed after wear indicated that the irradiated (i.e., crosslinked) cups exhibited a smaller proportion of, as well as shorter, fibrils in the wear debris and an increased crystallinity and melting temperature and that gamma irradiation in the low-oxygen environment reduced the level of oxidation and increased the level of crosslinking in the surface region of the cups.

Acetabulum↗
PubMed1999

Experimental evaluation of the effects of the intraportal administration of cyclic guanosine monophosphate on ischemia/reperfusion in the porcine liver.

This study was done to examine the protective effects of cyclic guanosine monophosphate (cGMP), a second messenger of nitric oxide, for ischemia/reperfusion injury of the liver, since it is known to induce vasodilatation and to inhibit platelet aggregation. Using an experimental model of porcine liver ischemia, 8-bromoguanosine 3',5' monophosphate, a cGMP analog, was continuously administered into the portal vein before ischemia and after reperfusion 30 min for each in the cGMP group (n = 6). Saline water was administered in the same way in the control group (n = 6). The cardiac output (CO), mean arterial blood pressure (MAP), portal venous flow (PVF), hepatic arterial flow (HAF), hepatic tissue blood flow (HTBF), and hepatic tissue cGMP level were determined. Hepatic enzymes and the bile discharge were also assessed as indicators of hepatic function. The hepatic tissue cGMP level was significantly higher, and PVF, HTBF, and the bile discharge were significantly greater in the cGMP group, while there were no remarkable differences between the groups with CO, MAP, HAF, and hepatic enzymes. In conclusion, the continuous supplementation of cGMP into the portal vein was found to be beneficial for preserving both the hepatic circulation and, consequently, the hepatic function after warm ischemia of porcine liver.

Analysis of Variance↗
PubMed1999

Fracture simulation of the femoral bone using the finite-element method: how a fracture initiates and proceeds.

Structural analysis of bones is now actively studied by many researchers using the finite-element method (FEM) to better understand the mechanism of bone fractures. Most previous studies, however, only obtained distribution patterns of stress or strain, and did not show how a fracture initiates and proceeds or how a fracture line grows. The purpose of this study was to simulate a fracture procedure using FEM and to assess its usefulness. Correlation of the strain value of the simulation and of the experiment was satisfactory (r = .81). The simulated fracture process and the consequent fracture lines were quite compatible with the experimental fracture. Quantitatively, however, there was a difference of yield load between the simulation and the experiment, i.e., 2000N and 8400N, respectively, likely caused by inaccuracies of material properties of the elements of the finite-element model.

Aged↗
PubMed1999

Comparison of bone mineral density at various skeletal sites with quantitative ultrasound parameters of the calcaneus for assessment of vertebral fractures.

This study investigated the role of quantitative ultrasound (QUS) for evaluation of fracture risk in comparison with bone mineral density (BMD) measurement. Our subjects were postmenopausal Japanese women (n = 260; age, 67 +/- 6.1 years) who were examined for bone densitometry, QUS, and spinal X-ray examination at our department between 1992 and 1996. The subjects were categorized into three groups by the number of atraumatic fractured vertebrae: NF, no vertebral fractures: F1, one vertebral fracture; F2, two or more vertebral fractures. We compared the measured parameters to determine their association with the number of fractured vertebrae. Differences among groups were compared and analyzed by Student's t-test. Odds ratios were also calculated after age adjustment, as well as age and lumbar or calcaneal parameters. Between NF and F1, lumbar BMD and BMD of the Ward's triangle showed more significant differences than other values, while between F1 and F2, whole-body BMD and QUS parameters showed more significant differences. Lumbar BMD also showed the highest age-adjusted odds ratio in differentiating F1 from NF. Although QUS parameters showed no power to differentiate between NF and F1, these values showed higher odds ratios than other measurements for discriminating between F1 and F2. Adjustment for bone density did not totally abolish the association between QUS parameters and vertebral fracture. Additionally, the combination of lumbar BMD and QUS ("stiffness") clearly showed a high power to discriminate NF from F1 + F2. In conclusion, we showed that QUS measurement is effective in evaluating fracture risk in advanced osteoporosis, while lumbar dual X-ray absorptiometry is effective in evaluating risk in early osteoporosis.

Aged↗
PubMed1999

Real-time, three-dimensional echocardiography: feasibility of dynamic right ventricular volume measurement with saline contrast.

BACKGROUND: The asymmetry and complex shape of the right ventricle have made it difficult to determine right ventricular (RV) volume with 2-dimensional echocardiography. Three-dimensional cardiac imaging improves visualization of cardiac anatomy but is also complex and time consuming. A newly developed volumetric scanning system holds promise of obviating past limitations. METHODS: Real-time, transthoracic 3-dimensional echocardiographic images of the right ventricle were obtained with a high-speed volumetric ultrasound system that uses a 16:1 parallel processing schema from a 2.5 MHz matrix phased-array scanner to interrogate an entire pyramidal volume in real time. The instrumentation was used to measure RV volume in 8 excised canine hearts; dynamic real-time 3-dimensional images were also obtained from 14 normal subjects. RESULTS: Three-dimensional images were obtained in vitro and in vivo during intravenous hand-agitated saline injection to determine RV volumes. The RV volumes by real-time 3-dimensional echocardiography are well correlated with those of drained in vitro (y = 1.26x - 9.92, r = 0.97, P <.0001, standard error of the estimate = 3.26 mL). For human subjects, the end-diastolic and end-systolic RV volumes were calculated by tracing serial cross-sectional, inclined C scans; functional data were validated by comparing the scans with conventional 2-dimensional echocardiographic indexes of left ventricular stroke volume. CONCLUSIONS: These data indicate that RV volume measurements of excised heart by real-time 3-dimensional echocardiography are accurate and that beat-to-beat RV quantitative measurement applying this imaging method is possible. The new application of real-time 3-dimensional echocardiography presents the opportunity to develop new descriptors of cardiac performance.

Animals↗
PubMed1999

Assessment of transmural coronary blood flow with intraoperative transesophageal color Doppler echocardiography during coronary revascularization.

Intraoperative color Doppler transesophageal echocardiography with a 4- to 7-MHz transducer was performed on 28 consecutive patients who underwent coronary artery bypass grafting to image and evaluate the transmural coronary blood flow before and after cardiopulmonary bypass. The transmural coronary flow was visualized in 26 (92.8%) of 28 patients in the inferior wall and in 13 (46.4%) of 28 patients in the lateral wall. The peak diastolic flow velocity of the transmural coronary artery in the inferior and lateral wall was significantly increased after coronary revascularization in patients with a successful bypass graft to the right coronary artery (from 34.0 +/- 19.7 to 64.9 +/- 30.9 cm/s, P <.001, n = 10) and to the left circumflex coronary artery (from 35.1 +/- 18.6 to 62.1 +/- 21.1 cm/s, P <.001, n = 10). No significant changes were observed in patients with no bypass graft to the right or left circumflex coronary artery. Coronary blood flow can be mapped and the velocity measured with Doppler transesophageal echocardiography with a high-frequency (4- to 7-MHz) transducer. Assessment of the transmural coronary flow may provide valuable information and aid in decision making during surgical revascularization.

Adult↗
PubMed1999

Real-time, 3-dimensional echocardiography acquires all standard 2-dimensional images from 2 volume sets: a clinical demonstration in 45 patients.

To test the hypothesis that real-time, 3-dimensional (3-D) echocardiography can obtain all standard 2-dimensional (2-D) views from acquisition of 2 volume sets, we scanned 45 patients (24 men, 21 women; mean age 49 +/- 17 years). This real-time 3-D device (VOLUMETRICS Medical Imaging, Durham, NC) uses a matrix phased array transducer in a 60 degree pyramidal volume. Images are displayed as 2 steerable, intersecting, conventional 2-D image sectors that can be oriented throughout 3-D space. By using this equipment, we were able to obtain 93.3% of standard views from a parasternal volume set and 85.2% of standard views from an apical volume set. The mean scanning time was 91 +/- 19 seconds for the parasternal volume set and 86 +/- 22 seconds for the apical volume set. We conclude that standard 2-D views can be obtained in the majority of patients by using this method. This equipment has the potential to substantially decrease the imaging time compared with the standard 2-D echocardiography.

Adolescent↗
PubMed1999

Assessment of regional wall motion abnormalities with real-time 3-dimensional echocardiography.

Accurate characterization of regional wall motion abnormalities requires a thorough evaluation of the entire left ventricle (LV). Although 2-dimensional echocardiography is frequently used for this purpose, the inability of tomographic techniques to record the complete endocardial surface is a limitation. Three-dimensional echocardiography, with real-time volumetric imaging, has the potential to overcome this limitation by capturing the entire volume of the LV and displaying it in a cineloop mode. The purpose of this study was to assess the feasibility of using real-time 3-dimensional (RT3D) echocardiography to detect regional wall motion abnormalities in patients with abnormal LV function and to develop a scheme for the systematic evaluation of wall motion by using the 3-dimensional data set. Twenty-six patients with high-quality 2-dimensional echo images and at least 1 regional wall motion abnormality were examined with RT3D echocardiography. For 2-dimensional echocardiography, wall motion was analyzed with a 16-segment model and graded on a 4-point scale from normal (1) to dyskinetic (4), from which a wall motion score index was calculated. Individual segments were then grouped into regions (anterior, inferoposterior, lateral, and apical) and the number of regional wall motion abnormalities was determined. The RT3D echocardiogram was recorded as a volumetric, pyramid-shaped data set that contained the entire LV. Digital images, consisting of a single cardiac cycle cineloop, were analyzed off-line with a computerized display of the apical projection. Two intersecting orthogonal apical projections were simultaneously displayed in cineloop mode, each independently tilted to optimize orientation and endocardial definition. The 2 planes were then slowly rotated about the major axis to visualize the entire LV endocardium. Wall motion was then graded in 6 equally spaced views, separated by 30 degrees, yielding 36 segments per patient. A higher percentage of segments were visualized with 2-dimensional versus RT3D echocardiography (97% vs 83%, respectively, P <.001). With the use of the 2-dimensional echocardiographic results as the standard, RT3D echocardiography detected 55 (96%) of 57 regional wall motion abnormalities. Analysis of the RT3D echocardiograms resulted in 3 false-negative and 5 false-positive findings. The total number of regional wall motion abnormalities was correctly classified by RT3D echocardiography in 19 (73%) of 26 patients. RT3D echocardiography detected 11 of 13 anterior, 19 of 20 inferoposterior, 9 of 9 lateral, and 15 of 15 apical wall motion abnormalities. An excellent correlation was found between the 2 techniques for assessment of the regional wall motion score index (r = 0.89, P <.001). This initial clinical study demonstrates the feasibility and potential advantages of RT3D echocardiography for the assessment of regional LV function. Compared with 2-dimensional echocardiography, this new method permits recording of the entire LV in a single beat, allowing the extent and location of the regional wall motion abnormalities to be determined.

Cardiomyopathy, Dilated↗
PubMed1999

Hamartoma of the urinary bladder.

BACKGROUND: Hamartomas of the urinary bladder are extremely rare. We report on a case in a 58-year-old female who presented with the chief complaint of pain on urination. METHODS/RESULTS: Cystoscopy revealed a solid tumor on the left posterior wall of the bladder. Transurethral resection of the tumor failed to provide a definitive pathological diagnosis of the tumor. Thus, we performed partial cystectomy. The pathological diagnosis was hamartoma arising from the urinary bladder. CONCLUSION: This is the ninth case diagnosed as urinary bladder hamartoma to be reported in the literature.

Cystoscopy↗
PubMed1999

Two cases of metastatic bladder cancers showing diffuse thickening of the bladder wall.

Metastatic bladder cancer showing diffuse thickening of the bladder wall is very rare. We report two cases of metastatic bladder cancer arising from a stomach cancer and acute lymphocytic leukemia. Hydronephrosis and diffuse thickening of the bladder wall were revealed by ultrasonography and computed tomography. Transurethral biopsy and percutaneous whole wall needle biopsy of the bladder were useful for diagnosis. The possibility of metastasis or recurrence of prior and other malignancies should therefore be considered when the clinical features described here are encountered.

Adenocarcinoma↗
PubMed1999

Expression of endothelin 3 by mesenchymal cells of embryonic mouse caecum.

BACKGROUND: Mutations in endothelin 3 (EDN3) and endothelin B receptor (EDNRB) genes cause terminal colonic aganglionosis in mice, and mutations in these genes have also been linked to the terminal aganglionosis seen in human Hirschsprung's disease. However, details of EDN3 expression during embryogenesis are lacking, and consequently the cellular mechanism by which EDN3 regulates innervation of the terminal gut is unclear. AIMS: To localise the expression of EDN3 and EDNRB in the embryonic mouse gut. METHODS: Expression of EDN3 and EDNRB mRNA was analysed by reverse transcription polymerase chain reaction and in situ hybridisation. RESULTS: High levels of EDN3 mRNA expression were restricted to mesenchymal cells of the caecum before and after the arrival of neural crest cells. In contrast, EDNRB expression along the gut displayed a time dependent pattern similar to those of the protein tyrosine kinase ret and the neural crest cell marker PGP9.5. CONCLUSIONS: Mesenchymal cells of the caecum express high levels of EDN3 mRNA during embryogenesis and hence the production of EDN3 at the caecum is likely to act on neural crest cells as a paracrine factor necessary for subsequent innervation of the terminal gut.

Animals↗
PubMed1999

[A case of mixed connective tissue disease with microscopic polyarteritis nodosa associated with perinuclear-antineutrophil cytoplasmic antibody and anti-glomerular basement membrane].

A 46-year-old female was admitted to our hospital due to general fatigue, systemic edema and dyspnea with history of systemic sclerosis (SSc). The patient was diagnosed as mixed connective tissue disease (MCTD) based on Raynaud phenomenon, a high anti-RNP antibody level and clinical symptoms and laboratory findings suggesting SSc, dermatomyositis (DM) and systemic lupus erythematosus (SLE). After the admission, both alveolar hemorrhage and a rapidly progressive glomerulonephritis (RPGN) also developed and laboratory findings showed a positive remark of myeloperoxydase-antineutrophil cytoplasmic antibody (MPO-ANCA) and anti-glomerular basement membrane (GBM) antibody. She was therefore re-diagnosed as microscopic polyarteritis nodosa (microscopic PAN) combined with MCTD and treatment with high dose prednisolone and steroid pulse therapy dramatically improved general conditions and lung symptoms, but maintenance dialysis was persistent because of irreversible renal failure. However, 3 months after the admission, she died of acute exacerbation of interstitial pneumonitis that was unresponsive to steroid pulse therapy. Autopsy revealed interstitial pneumonitis with alveolar hemorrhage and crescentic glomerulonephritis (CrGN), in which immunofluorescent microscopy showed no deposition in agreement with pauciimmune type. The histological findings supported the diagnosis; primary microscopic PAN combined with MCTD, which is a quite rare case, to our knowledge. Furthermore, co-existence of MPO ANCA and anti-GBM antibody, clinical and histological findings of the case also lead us to reconsider the relevance of these antibodies to pathogenesis and/or categories of microscopic PAN and Goodpasture's syndrome.

Antibodies, Antineutrophil Cytoplasmic↗