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S Tamura

Publications and source records attributed to S Tamura.

At least 37 records · Page 2Linked to original sources
PubMed2004

Foxp1 gene expression in projection neurons of the mouse striatum.

The developmental processes of maturation in the CNS are the result of specific events including mitogenesis, differentiation, and cell death which occur in a precise spatial and temporal manner. It has been reported that many transcription factors, including forkhead transcription factors, play a key role in these processes. First, we examined the expression pattern of the forkhead transcription factor Foxp1 in the adult CNS. Foxp1 was highly expressed in the striatum and moderately in the cerebral cortex, CA1/2 subfields of the hippocampus, and several thalamic nuclei. In situ hybridization combined with immunohistochemistry in the striatum of adult mice revealed that Foxp1 mRNA was detected in a subset of projection neurons, not in interneurons. In addition, the expression of Foxp1 mRNA was observed in the developing basal ganglia with the exception of the globus pallidus. Thus, Foxp1 mRNA was expressed in a subset of striatal projection neurons, probably the matrix neurons. The expression pattern of Foxp1 mRNA suggests that Foxp1 may play a role in the development and formation of a circuit in the basal ganglia, which is involving the matrix neurons.

Animals↗
PubMed2004

Conversion to cyclosporine provides valuable rescue therapy for living donor adult liver transplant patients intolerant to tacrolimus: A single-center experience at the University of Tokyo.

Tacrolimus-based immunosuppression is currently accepted as mainstream therapy in many transplant centers worldwide due to its potent immunosuppressive activity compared to cyclosporine. A tacrolimus-based regimen has been successfully used for our living donor liver transplantation (LDLT) recipients. Adverse effects such as neurotoxicity, nephrotoxicity, and new-onset diabetes mellitus, however, have limited its clinical application. In deceased donor liver transplantation, cyclosporine rescue therapy is valuable for such complications, but few reports have described a strategy for conversion in LDLT. Herein, we present our experience of conversion from tacrolimus to cyclosporine therapy in adult LDLT recipients. Among 203 recipients, 37 patients (18%) required conversion, primarily for neurotoxicity (41%), diabetes mellitus (16%), hematopoietic disorder (16%), and gastrointestinal intolerance (11%). Primary adverse events resolved within 2 months after conversion in 35/37 (94%) of the patients. For LDLT recipients unable to maintain effective immunosuppression with tacrolimus, conversion to cyclosporine is an effective option.

Adult↗
PubMed2004

Factors affecting metabolic and electrolyte changes after reperfusion in liver transplantation.

BACKGROUND: The metabolic and electrolyte changes were evaluated after various durations of cold and warm ischemia times to correlate ASA status with hemodynamic changes that may affect the severity of the reperfusion syndrome. PATIENTS AND METHODS: Sixty-one patients who underwent liver transplantation (OLT) were monitored by arterial pH, PaO2, PaCO2, HCO2, BE, K+, Ca2+, Na+, GL, and serial Ht at three specific times: after the skin incision (baseline), 10 minutes before reperfusion (T2), and 10 minutes after reperfusion (T3). Changes in metabolic parameters were correlated with ASA status, hemodynamic changes, time of OLT, as well as cold and warm ischemia times. RESULTS: The pH in ASA IV patients was significantly lower at T1 and T3, and PCO2 higher in ASA V at T1. A significant correlation was observed between pH, PaCO2, HCO3-, BE, Na+, Ca2+, and glucose with the phase of the procedure. The pH and HCO3- decreased significantly from T1 and T2, increasing during T3. Ca2+ fell from T1 to T2 increasing in T3. Mean glucose and sodium levels increase from T1 to T3. Mean BE dropped from T1 to T2 and increased at T3 without a significant correlation between the metabolic parameters in any phase of the study and the cold or warm ischemia times. Patients with a high ASA status showed an increased risk for cardiovascular collapse after reperfusion. CONCLUSIONS: Patients with advanced ASA status are more prone to metabolic and acid-base disturbances during reperfusion, without any relation to the cold or warm ischemia times. High ASA status shows an increased risk for cardiovascular collapse after reperfusion.

Adult↗
PubMed2004

Interferon treatment improves survival in chronic hepatitis C patients showing biochemical as well as virological responses by preventing liver-related death.

Interferon therapy for chronic hepatitis C reduces the risk of hepatocellular carcinoma, especially among virological and biochemical responders. However, little is known about the effect of interferon therapy on mortality. We studied the long-term effect of interferon therapy on mortality in patients with chronic hepatitis C. For this retrospective cohort study, 2954 patients with chronic hepatitis C were recruited, of whom 2698 received interferon therapy and 256 did not. The effect of interferon therapy on survival was assessed by standardized mortality ratio (SMR) based on published mortality data for the general Japanese population and by risk ratio calculated by proportional hazard regression. Over 6.0 +/- 2.2 years follow-up, death from liver-related diseases was observed in 69 (68%) of 101 deaths among interferon-treated patients and in 42 (81%) of 52 deaths among untreated patients. Compared with the general population, overall mortality was high among untreated patients (SMR: 2.7; 95% CI: 2.0-3.6) but not among interferon-treated patients (SMR: 0.9; 95% CI: 0.7-1.1). Liver-related mortality was extremely high among untreated patients (SMR: 22.2; 95% CI: 16.0-30.0) and less among interferon-treated patients (SMR: 5.5; 95% CI: 4.3-6.9). The risk of death from all causes was lower for interferon-treated than untreated patients (risk ratio: 0.47; 95% CI: 0.261-0.836; P = 0.01). The risk of death from liver-related diseases was significantly lower for sustained virological responders (risk ratio: 0.04; 95% CI: 0.005-0.301; P = 0.002) compared with untreated patients, but not for nonsustained virological responders. Sustained biochemical responders (risk ratio: 0.03; 95% CI: 0.004-0.230; P < 0.001) and transient biochemical responders (risk ratio: 0.18; 95% CI: 0.063-0.532; P = 0.002) showed a significantly reduced risk of death from liver-related death, whereas biochemical nonresponders did not. Hence interferon treatment improved survival in chronic hepatitis C patients showing a biochemical as well as a virological response by preventing liver-related deaths.

Adult↗
PubMed2004

Evaluation of endoscopic mucosal resection for laterally spreading rectal tumors.

BACKGROUND AND STUDY AIMS: We undertook this retrospective study to evaluate the frequency and prognosis of endoscopic treatment of laterally spreading tumors (LSTs) in the rectum. The recurrence rate for lesions of the lower rectum was compared with that of the upper rectum. PATIENTS AND METHODS: During the period from July 1989 to June 2002, a total of 1237 rectal tumors were detected. LSTs accounted for 6.9 % (85/1237) of all rectal tumors. A total of 224 tumors of the lower rectum were detected among the 1237 rectal tumors. LSTs accounted for 16.1 % (36/224) of all the lower rectal tumors. From 85 LST lesions, 67 were evaluated for their prognosis after endoscopic mucosal resection (EMR). Patients whose LSTs had been resected were followed up by endoscopy at the following frequencies: once 15 (22.4 %); twice (more than 1 year), 20 (29.9 %); three times (more than 3 years), 21(31.3 %); and four times or more (more than 5 years), 11 (16.4 %). RESULTS: A total of 67 patients with endoscopically treated LSTs were followed up by endoscopy. We observed recurrences in two lesions of the upper rectum (2/38, 5.3 %) and five lesions of the lower rectum (5/29, 17.2 %) (P = 0.2364); all seven lesions were resected piecemeal. LSTs whose horizontal margin reached the pectinate line frequently recurred in the lower rectum, at a rate of 80 % (4/5). However, all patients were completely cured by additional endoscopic resections, the greatest number of treatments being four. CONCLUSION: For early detection of recurrence and successful endoscopic cure, further colonoscopic examination within a few months after the first treatment is necessary.

Adenoma↗
PubMed2003

Development of autoimmune diabetes in glutamic acid decarboxylase 65 (GAD65) knockout NOD mice.

AIMS/HYPOTHESIS: Type 1 diabetes mellitus, a T-cell-mediated autoimmune disease, results from the selective destruction of insulin-producing pancreatic beta cells. Autoantibodies against beta-cell components are used clinically as sensitive markers of this disease; however, their physiological role has not been clear. To investigate the role of glutamic acid decarboxylase 65 (GAD65) in the development of the Type 1 diabetes of non-obese diabetic (NOD) mice, we analysed and characterised NOD mice with targeted disruption of the GAD65 gene. METHODS: GAD65-deficient mice were previously established. After backcrossing the knockout mutation onto the NOD genetic background for up to eight generations, female littermates of the three resulting genotypes were produced by intercrossing: GAD65 +/+ (n=23), GAD65 +/- (n=62), and GAD65 -/- (n=31). RESULTS: The cumulative incidence of autoimmune diabetes showed no significant difference among the three groups in longitudinal studies using the Kaplan-Meier method. Islet morphology showed that the progression of islet infiltration did not differ significantly between the three groups. CONCLUSION/INTERPRETATION: The cumulative incidence of autoimmune diabetes was not influenced by the GAD65 deficiency. These data suggest that GAD65 is not a major regulatory target of beta-cell autoimmunity in NOD mice.

Age Factors↗
PubMed2003

Localization of oncostatin M receptor beta in adult and developing CNS.

Oncostatin M (OSM) is a member of the interleukin-6 cytokine family, which is involved in definitive hematopoiesis, the development of liver, and local inflammation. However, little is known about the role of OSM in the murine CNS. Using Northern blot analysis, we examined the regional distribution of OSM receptor beta (OSMRbeta) mRNA in the adult CNS. OSMRbeta mRNA was observed predominantly in the olfactory bulb, and with low levels in the other regions. In situ hybridization shows that OSMRbeta gene expression was found in astrocytes of olfactory bulb, epithelial cells of choroid plexus, and meningeal cells in pia mater. In addition, we investigated the gene expression of OSMRbeta in the developing CNS at different time points. Its gene expression was first observed in large neurons of the hypoglossal nucleus at 14.5 days postcoitum, which was sustained until neonatal mice. OSMRbeta mRNA and protein were mainly localized in the ventral subnucleus of the developing hypoglossal nucleus. Our results suggest that OSM contributes to the development of specific subpopulations of both neurons and astrocytes in the murine CNS.

Animals↗
PubMed2003

Mucoepidermoid carcinoma of the esophagus treated by endoscopic mucosal resection.

Mucoepidermoid carcinoma is a mixed cell tumor with both adenocarcinomatous and squamous components. We report a rare case of superficial mucoepidermoid carcinoma of the esophagus with mucosal gastric cancer. Endoscopic mucosal resection was performed on a 67-year-old man with a slight but defined depressed lesion of the thoracic esophagus and two lesions of mucosal gastric cancer. Histological examination revealed that the lesion of the esophagus was a mucoepidermoid carcinoma and the two lesions of the stomach were well-differentiated adenocarcinoma. Since the mucoepidermoid carcinoma had only slightly invaded the submucosal layer, it was thought to arise from the ductal epithelium of the esophageal gland or the stratified squamous epithelium of the esophagus. Radiation therapy with a total dose of 60 Gy was performed and there has been no recurrence or metastasis to other organs during 36 months of follow-up.

Aged↗
PubMed2003

A novel radiopharmaceutical for detection of malignant melanoma, based on melanin formation: 3-iodo-4-hydroxyphenyl-L-cysteine.

The aim of this study was to develop a new artificial amino acid radiopharmaceutical labelled with radioiodine for detection of malignant melanoma, based on melanin formation. By considering the affinity for tyrosinase, a starting enzyme on the branching point to melanin biosynthesis, 3-[125I]iodo-4-hydroxyphenyl-L-cysteine (125I-L-PC) was synthesized and evaluated biologically. Labelling of 125I-L-PC using the chloramine-T method was carried out conveniently and efficiently in a short period of time, with high specific activity. In a biodistribution study, 125I-L-PC showed a low accumulation in normal tissue and relative retention in B16 melanoma. A high contrast image of peripheral tumour was obtained during autoradiography. During an in vitro accumulation study, inhibition of 125I-L-PC with a tyrosinase inhibitor suggested interaction of this tracer with tyrosinase. It indicates that the uptake mechanism of 125I-L-PC to melanoma tissue was dependent on high tyrosinase activity in melanoma cells. Thus, 125I-L-PC appears to be a promising radioiodinated amino acid radiopharmaceutical for imaging malignant melanoma in relation to melanin formation, namely specific metabolism with high tyrosinase activity.

Animals↗
PubMed2003

Parathyroid scintigraphy with 99mTc-MIBI and 123I subtraction: a comparison with magnetic resonance imaging and ultrasonography.

The aim of this study was to evaluate the efficacy of 99mTc-MIBI and 123I subtraction scintigraphy for the detection of abnormal parathyroid glands to be referred for surgical treatment. Thirty-nine consecutive patients, including 35 primary and four secondary cases of hyperparathyroidism, were evaluated. 99mTc-MIBI/123I subtraction scintigraphy (MIBI/I) was performed on all patients, and the results were compared with delayed images of 99mTc-MIBI (D-MIBI), magnetic resonance imaging (MRI) and ultrasonography (US). The overall sensitivity of MIBI/I, MRI, US and D-MIBI was 55.9%, 43.4%, 50.8% and 39.0%, respectively. In cases of single-gland disease, the sensitivity of MIBI/I, MRI, US and D-MIBI was 62.1%, 48.3%, 55.2% and 44.8%, respectively. In cases of multi-gland disease, the sensitivity of MIBI/I, MRI, US and D-MIBI was 50.0%, 37.5%, 46.7% and 36.7%, respectively. In cases of parathyroid adenoma, the sensitivity of MIBI/I, MRI, US and D-MIBI was 71.4%, 50.0%, 71.4% and 50.0%, respectively. In cases of parathyroid hyperplasia, the sensitivity of MIBI/I, MRI, US and D-MIBI was 55.2%, 42.3%, 50.0% and 39.7%, respectively. It is concluded that 99mTc-MIBI/123I subtraction is more useful than the delayed imaging of 99mTc-MIBI, MRI and US.

Adolescent↗
PubMed2002

Development of a multilayer Fresnel zone plate for high-energy synchrotron radiation X-rays by DC sputtering deposition.

Hard X-ray microscopy with high spatial resolution ( or=20 keV) because a large thickness (aspect ratio) can be available. Various types of multilayer FZPs have been fabricated by DC sputtering deposition. Their focusing characteristics have been evaluated at the high-brilliance undulator beamline BL47XU of SPring-8. An optical system using a Cu/Al multilayer FZP (with an outermost zone width of 0.25 microm) as the focusing optics fabricated by the optimum deposition condition with precise film (zone) thickness control has attained an almost diffraction-limited microbeam of 0.3-0.35 microm at 8.9 keV. A line-and-space resolution test pattern has been observed: fine structures up to 0.2 microm were clearly observed in the measured image. This FZP has been working since 1995, keeping good focusing characteristics. It can be said from these results that a spatial resolution better than 0.1 microm in the high-energy X-ray region is in prospect by the development of a multilayer FZP with a narrower outermost zone width in the near future.

Journal Article↗
PubMed2002

Hard X-ray microbeam experiments with a sputtered-sliced Fresnel zone plate and its applications.

Hard X-ray microbeam experiments with sputtered-sliced Fresnel zone plates have been performed. Zone plates with an outermost zone width of 0.25 microm (#FZP1) and 0.1 microm (#FZP2) were fabricated and evaluated. In a scanning X-ray microscopy experiment, a line-and-space pattern with structure as fine as 0.1 microm was resolved using #FZP2 at an X-ray wavelength of 1 A. As an application of the microbeam technique, a two-dimensional distribution of constituent elements in forensic samples has been obtained (e.g. section view of human and elephant hairs) using fluorescent scanning microscopy.

Animals↗
PubMed2002

Zernike-type X-ray imaging microscopy at 25 keV with Fresnel zone plate optics.

A Zernike-type imaging microscope using a sputtered-sliced Fresnel zone plate (SS-FZP) has been developed and tested at an X-ray energy of 25 keV. The SS-FZP was used as an objective. A copper (Cu) phase plate was placed at the back focal plane of the SS-FZP in order to produce phase contrast. The performance of the Zernike-type imaging microscope was tested with a gold (Au) mesh and a resolution test pattern at undulator beamline 47 of SPring-8. The Au mesh and the resolution test pattern could be imaged in transmission with a magnification of x10.2. Owing to the Cu phase plate, different image contrast was observed compared with the bright-field image contrast. Tantalum microstructures down to 0.5 microm line-and-space have been observed on spatial resolution test patterns.

Journal Article↗
PubMed2002

Watching ripples on crystals.

We present a new method for imaging surface phonon focusing and dispersion at frequencies up to 1 GHz that makes use of ultrafast optical excitation and detection. Animations of coherent surface phonon wave packets emanating from a point source on isotropic and anisotropic solids are obtained with micron lateral resolution. We resolve rounded-square shaped wave fronts on the (100) plane of LiF and discover isolated pockets of pseudosurface wave propagation with exceptionally high group velocity in the (001) plane of TeO(2). Surface phonon refraction and concentration in a minute gold pyramid is also revealed.

Journal Article↗
PubMed2002

Increased plasma HB-EGF associated with obesity and coronary artery disease.

The mechanism by which the obese subjects are more associated with vascular disease remains unclear. We reported that the adipose tissues produce and secrete many bioactive molecules, conceptualized as adipocytokines. Heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), produced locally by vascular macrophages and smooth muscle cells, has been suggested to induce the migration and proliferation of vascular smooth muscle cells. The current study reveals that (1) HB-EGF mRNA is abundantly expressed in human adipose tissue, (2) HB-EGF mRNA increases in the fat tissues of obese mice, (3) plasma HB-EGF levels increase in parallel with fat accumulation in human, and (4) the subjects with coronary artery disease have higher plasma HB-EGF levels, associated with fat accumulation. These results suggest that increased plasma HB-EGF derived from the accumulated fat contributes to the higher incidence of vascular disease in obesity, proposing HB-EGF as an adipocytokine directly linking adipovascular axis.

Adipose Tissue↗
PubMed2002

Augmentation effect of postprandial hyperinsulinaemia on growth of human hepatocellular carcinoma.

BACKGROUND: Cirrhotic patients with hepatocellular carcinoma (HCC) frequently have impaired glucose metabolism. AIMS: To investigate whether impaired glucose metabolism affects the growth rate of the tumour. PATIENTS AND METHODS: Tumour doubling time (DT), assessed by ultrasound imaging analysis, was measured in 60 patients with single small HCC (diameter <30 mm). DT was compared with plasma insulin and glucose concentrations following the oral glucose tolerance test (OGTT). The effect of continuous infusion of octreotide (a somatostatin analogue 200 microg/day) for three months on DT in five cases was assessed. RESULTS: The 60 patients were divided into two groups because the median DT was 140 days: rapid growth group (DT 140 days, n=30). Fasting plasma insulin concentration and area under the plasma insulin curve (AUC(ins)) of the OGTT (10.4 (6.2) microU/ml and 262 (152) microU/ml/h, respectively; mean (SD)) in the rapid growth group were significantly higher than those in the slow growth group (7.6 (4.3) and 146 (140), respectively) (p=0.041 and p=0.0006, respectively). In contrast, fasting plasma glucose concentration and area under the plasma glucose curve (AUC(gluc)) in the rapid growth group were significantly lower than those in the slow growth group (p=0.0003 and p=0.0012, respectively). Univariate and multivariate analyses of logistic regression models demonstrated that AUC(ins) was a significant factor contributing to the growth rate of HCC (p=0.001 and p=0.016, respectively). AUC(ins) significantly decreased after octreotide treatment (p<0.02) but AUC(gluc) did not significantly change. DT after treatment increased in three of the five patients and could not be calculated in the remaining two patients because of no change in the diameter of the tumour. CONCLUSIONS: These data suggest that postprandial hyperinsulinaemia is associated with accelerated HCC growth.

Area Under Curve↗