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S Tamura

Publications and source records attributed to S Tamura.

At least 235 records · Page 13Linked to original sources
PubMed1998

Contamination of mouse-adapted influenza virus with Sendai virus.

In our laboratory animal facility, Sendai virus (HVJ) contamination occurred in a negative flow rack used for experimental infection with 4 strains of mouse-adapted influenza virus (Inf.V). Anti-HVJ antibody (Ab) was detected in 35/42 mice in the rack. To specify the strain of Inf.V contaminated with HVJ, experimental infection was performed by using A, B and D strains of Inf.V in each vinyl isolator. Anti-HVJ Ab was detected in all mice infected with A strain at day 28 post-infection. As a result of experimental infection with A strain of Inf.V which was treated with anti-HVJ mouse serum, the virus suspension was determined not to contain HVJ and allowed for experimental use in our facility, Since then, HVJ contamination has not occurred in our facility.

Animals↗
PubMed1998

Multiple fractionated and single-dose irradiation of bone marrow. Evaluation by MR and correlation with histopathological findings.

PURPOSE: To evaluate the MR appearance of bone marrow during and after multiple fractionated and single-dose irradiation using SE sequences, with histopathological correlation. MATERIAL AND METHODS: The left hind limbs of Wistar rats were irradiated with doses of either 2 Gy x 10 fractions or 20 Gy as a single dose. MR images of the femora were taken on days 0, 1, 3, 5, 7, 10, 15, 20, 25, 30, 40, 50, 60, 90, 120, 150 and 180. T1-, proton-density- and T2-weighted images were obtained with SE sequences. The rats were sacrificed on days 3, 12, 40 and 180 for histological study. RESULTS: No significant change in the T1 relaxation time was observed in the fractionated group during the first 15 days after irradiation. T2 did not change during the initial 7 days. There were significant differences in T1 and T2 between nonirradiated and fractionated, and between fractionated and single-dose irradiated marrows (p < 0.01). Sinusoidal dilatation, decrease in cellularity, and hemorrhage were observed on day 3. Fat increased on/after day 12. The fractionated group showed mild changes compared to the single-dose irradiated group. CONCLUSION: The T1 and T2 relaxation times of bone marrow receiving multiple fractionated irradiation did not change significantly on SE sequences during the early phase. However, dilatation of sinusoids, hemorrhage, decrease in cellularity, and increase in fat content were observed. Single-dose irradiation resulted in marked and early changes in T1 and T2 of the bone marrow.

Animals↗
PubMed1998

Cytogenetic analysis of de novo acute myeloid leukemia with trilineage myelodysplasia in comparison with myelodysplastic syndrome evolving to acute myeloid leukemia.

Characteristics of karyotypes were analyzed in de novo acute myeloid leukemia (AML) with trilineage myelodysplasia (AML/TMDS) at initial diagnosis and compared with myelodysplastic syndrome (MDS) cases that had evolved to AML (MDS/AML). Abnormal karyotypes were seen in 11 of 19 patients with AML/TMDS and 13 of 16 MDS/AML cases. Trisomy 8 was observed in 3 AML/TMDS cases as a sole anomaly and was also present in 3 MDS/AML cases but not as a sole finding. Although MDS/AML frequently displayed monosomies or long-arm deletions of chromosome 5, 7 and 9, only one case exhibited long-arm deletion (of chromosome 7) in AML/TMDS. Two or more chromosome aberrations were found in some cases in both groups. These findings suggest that AML/TMDS had passed through several preleukemic stages at diagnosis, as has been well documented in MDS and MDS/AML. Additionally, clonal evolution may have already occurred in AML/TMDS, as MDS transformed to AML is associated with clonal evolution.

Acute Disease↗
PubMed1998

[Hemochromatosis].

Explore the source record for details and available documents.

Glucose Intolerance↗
PubMed1998

[Evaluation of brain tumor by 99mTc-MIBI: comparison study with 201Tl and predictivity of therapeutic effect].

We compared the detectability of 99mTc-MIBI and 201Tl-chloride for brain tumor in relationship with histopathology. We also evaluated correlation between therapeutic effect using ACNU, Cisplatine and the degree of MIBI tumor uptake. The subjects were 31 brain tumor histologically confirmed by operation or biopsy. Dual-isotope SPECT technique was performed at both 20 min and 180 min after tracer injection. A tumor to normal lung ratio on both early (ER) and delayed image (DR) and retention index (RI) were calculated. The positive rates of 99mTc-MIBI (90.3% and 77.4%) were comparable to that of 201Tl (90.3% and 80.6%). In the relationship with histopathology, both MIBI and Tl accumulated in 100% of glioblastoma (GBM), metastasis (meta), anaplastic astrocytoma and 25% of low grade astrocytoma on both early and delayed images. On semiquantitative analysis, there were no statistical significance among GBM, meta and anaplastic astrocytoma of ER, DR, RI in the both radiopharmaceuticals. However, both ER and DR in GBM tended to be higher than those of anaplastic astrocytoma. In spite of intense MIBI uptake, GBM patients died within six months except one patient. We concluded that MIBI can be helpful in detecting brain tumor as Tl. MIBI also might be useful in estimating the degree of malignancy in glioma. However, intense MIBI uptake did not mean favorable therapeutic effect in patients with GBM treated with ACNU and Cisplatine.

Adult↗
PubMed1998

[Discrepancy between surgeon's binocular parallax perception and manipulation in the neurosurgical operation].

The application of virtual reality (VR) to the neurosurgical field has been increasing recently, however, the relation between the surgeon and the VR environment is rarely studied. We examined the trajectory of a surgical instrument during manipulation of a virtual object using a video-see-through microscope and a neurosurgical navigator (CANS Navigator) to find better surgeon-microscope interface. A resin cylindrical phantom was produced representing the surgical field, which included two 3 dimensionally arranged small spheres and a virtual 'gate'. The phantom was fixed and set under the microscope with a skull clamp mimicking conditions in an ordinary craniotomy. Firstly, the binocular parallax perception under microscope was examined. Experienced and inexperienced neurosurgeons were asked to learn the position of the virtual 'gate' for 3 minutes. Then, after 5 minutes to point with the navigator probe (suction tube), under various conditions; under the naked eyes, under the microscope, under the navigator without observing the phantom, and under the microscope with picture in picture (PIP) display of the navigational image. The positions of the suction tube were recorded at real time into the navigator for later analysis. Secondly, the task performance in this VR environment was studied by analyzing the trajectory of the suction tube from one sphere to the other sphere passing the virtual 'gate' under various conditions. A significant difference in pointing precision between experienced and inexperienced neurosurgeons was able to be observed only under microscope. This difference was mainly derived from overestimation of the depth of the virtual 'gate' by the inexperienced neurosurgeons. Among the above conditions, pointing under the microscope with PIP was able to be performed the most precisely and the most promptly. This study disclosed the presence of stereoscopic distortion in the microscope. The PIP display of the navigational image in the microscopic view remarkably improved the task performance, which could be accounted for by the correction of the somewhat distorted binocular parallax perception under the neurosurgical microscope by the provision of another visual key.

Brain↗
PubMed1998

[Aortic and mitral valve aneurysms complicated with infective endocarditis: a case report].

A rare case of aortic and mitral valve aneurysms complicated with infective endocarditis was accurately diagnosed by transesophageal echocardiography. A 57-year-old man with severe aortic regurgitation due to infective endocarditis was admitted to our hospital. Transthoracic echocardiography showed an aortic valve aneurysm on the right coronary cusp and perforations on the other cusps. Transesophageal echocardiography demonstrated a small aneurysm on the anterior leaflet of the mitral valve which was not clearly visualized by transthoracic echocardiography. Color Doppler echocardiography revealed severe aortic regurgitation and mild mitral regurgitation without perforation of the mitral valve aneurysm. Aortic valve replacement and mitral valvuloplasty of the anterior mitral leaflet were performed. The right coronary cusp of the aortic valve showed marked thinning with infiltration of inflammatory cells. The postoperative clinical course was uneventful.

Aortic Valve↗
PubMed1998

Pancreatic invasion as the prognostic indicator of duodenal adenocarcinoma treated by pancreatoduodenectomy plus extended lymphadenectomy.

UNLABELLED: Pancreatoduodenectomy has become the standard procedure in resection of the duodenal adenocarcinoma, and some adjuvant therapies can be added to obtain further improvement in postoperative outcome. However, for patient selection, it is necessary to have a predictive indicator showing, if possible before laparotomy, which instances are noncurable by surgery alone or need adjuvant therapies. METHODS: A retrospective analysis was made for 24 consecutive patients whose duodenal adenocarcinoma were treated by pancreatoduodenectomy plus a wide range of lymphadenectomies without any adjuvant therapies at Osaka Medical Center for Cancer and Cardiovascular Diseases. Patient survival rates were related to macroscopic and microscopic findings and to findings obtained by preoperative imaging techniques. RESULTS: The overall survival rate was 69% at 3 years and 57% at 5 years; locoregional recurrence was the primary cause of death. Although the 5-year survival rate was 44% in patients with nodal involvement and 76% in those without, this difference did not reach statistical significance (P = .079). Instead, invasion into the pancreatic parenchyma at a macroscopic level was the most significant prognostic factor; the 5-year survival rate was 78% in the 16 patients without and 16% in the 8 patients with pancreatic invasion (P = .0047). Invasion into the pancreas correlated well with the angiographic findings; the 5-year survival rate was 25% in patients whose angiograms delineated the pancreatic invasion and 83% in patients whose angiograms did not (P = .0084). CONCLUSION: When duodenal adenocarcinoma was treated by pancreatoduodenectomy plus a wide range of lymphadenectomy, pancreatic invasion at a macroscopic level was most associated with patient survival. Pancreatic invasion was well delineated by the preoperative angiogram, which would be helpful in patient selection.

Adenocarcinoma↗
PubMed1998

Effects of superoxide and peroxynitrite on vascular tension in the human umbilical artery.

BACKGROUND: While nitric oxide (NO) has been demonstrated to regulate vascular tone, superoxide (O2-) may also have an important role in regulating tension in the human fetoplacental vasculature. We therefore evaluate the effects of O2- and peroxynitrite (ONOO-) on vascular tension in isolated human umbilical arteries. METHODS: Helical sections of umbilical arteries were obtained from healthy pregnant women who were delivered between weeks 37 and 39 of gestation. Changes in maximal potassium chloride (KCl)-induced tension were measured in umbilical artery segments with intact endothelium. RESULTS: We found that hypoxanthine plus xanthine oxidase significantly potentiated vascular tension, and that this effect was suppressed by pretreatment with L(NG)-monomethyl arginine (LNMA). Pretreatment with hypoxanthine plus xanthine oxidase, however, significantly inhibited the relaxation induced by the calcium ionophore A23187. 3-morpholinosydomine (SIN-1), which releases O2- and NO simultaneously produced a significant dose-dependent relaxation of vascular tension, which pretreatment with hemoglobin did not affect SIN-1-induced relaxation. Pretreatment with methylene blue significantly attenuated, while pretreatment with superoxide dismutase (SOD) significantly potentiated this effect. CONCLUSION: These findings suggest that O2- potentiates vascular tension in human umbilical artery, in part, by suppressing NO synthesis in the endothelium. The vasorelaxation by exogenously generated ONOO suggests that this moiety has biological relevance in vasoregulation of the human umbilical artery.

Female↗
PubMed1998

Scalp localization using a simple algorithm.

We have developed a simple algorithm for scalp localization for craniotomy. Using a series of CT/MRI data, the point on the scalp closest to the center of the lesion (T) is determined by our program. A plane (plane R) is defined by three points: bilateral auditory meati and T. Point S is the intersection of three planes: the plane R, the scalp surface and the midsagittal plane. The distance from either S or the ipsilateral external auditory meatus to T is measured along the scalp surface on the plane R. The distance from the nasion to S along the scalp surface on the midsagittal plane is also measured. To determine the craniotomy site, these distances are measured directly on a patient's scalp in the operating room. This simple and accurate method for scalp localization could be used by installing our program in conventional CT/MR scanners.

Aged↗
PubMed1997

CGP 57148, a tyrosine kinase inhibitor, inhibits the growth of cells expressing BCR-ABL, TEL-ABL, and TEL-PDGFR fusion proteins.

CGP 57148 is a compound of the 2-phenylaminopyrimidine class that selectively inhibits the tyrosine kinase activity of the ABL and the platelet-derived growth factor receptor (PDGFR) protein tyrosine kinases. We previously showed that CGP 57148 selectively kills p210BCR-ABL-expressing cells. To extend these observations, we evaluated the ability of CGP 57148 to inhibit other activated ABL tyrosine kinases, including p185BCR-ABL and TEL-ABL. In cell-based assays of ABL tyrosine phosphorylation, inhibition of ABL kinase activity was observed at concentrations similar to that reported for p210BCR-ABL. Consistent with the in vitro profile of this compound, the growth of cells expressing activated ABL protein tyrosine kinases was inhibited in the absence of exogenous growth factor. Growth inhibition was also observed with a p185BCR-ABL-positive acute lymphocytic leukemia (ALL) cell line generated from a Philadelphia chromosome-positive ALL patient. As CGP 57148 inhibits the PDGFR kinase, we also showed that cells expressing an activated PDGFR tyrosine kinase, TEL-PDGFR, are sensitive to this compound. Thus, this compound may be useful for the treatment of a variety of BCR-ABL-positive leukemias and for treatment of the subset of chronic myelomonocytic leukemia patients with a TEL-PDGFR fusion protein.

Animals↗
PubMed1997

Structure and alternative promoters of the mouse glutamic acid decarboxylase 67 gene.

gamma-Aminobutyric acid is synthesized by glutamic acid decarboxylase (GAD), which has two forms, GAD65 and GAD67. Genomic clones coding mouse GAD67 (mGAD67) have been isolated. The restriction map of the overlapping clones covers a region of more than 45 kb of genomic DNA. The mGAD67 gene contains 16 translated exons in addition to an exon which is preferentially expressed in foetal brain. The rapid amplification of 5'-cDNA ends showed that mGAD67 gene transcripts have two different 5'-untranslated regions. Analysis of the genomic clones encompassing the 5'-exons revealed that the two transcripts arose from a single gene by alternative splicing using two different donor sites and a common acceptor. The exons were found 1.5 and 0.6 kb upstream of exon 1. The corresponding promoter regions of these exons have a number of putative regulatory elements, including Sp1- and Krox-24-binding sites. Analysis of mGAD67 transcripts demonstrated that each of the 5'-untranslated exons was expressed in mouse brain. In contrast, exon 0A, but not exon 0B, was expressed in mouse testis and pancreas. These results suggest that these transcripts may be regulated under the control of independent promoters.

Alternative Splicing↗
PubMed1997

Specificity of different isoforms of protein phosphatase-2A and protein phosphatase-2C studied using site-directed mutagenesis of HMG-CoA reductase.

We have expressed the catalytic domain of Chinese hamster HMG-CoA reductase, and 13 point mutations involving the region around the single phosphorylation site for AMP-activated protein kinase. After phosphorylation, these were used to test the specificity of isoforms of protein phosphatase-2A [bovine PP2A(C) (catalytic subunit) and PP2A1 (ABC heterotrimer)] and protein phosphatase-2C (human alpha; mouse alpha, beta1, beta2, beta3, beta4, beta5). PP2A1 had > 50-fold higher activity for HMG-CoA reductase variants than PP2A(C), but their relative selectivity for different variants was similar. Although the specificities of PP2A and PP2C were distinct, no dramatic differences in selectivity were observed between different PP2C isoforms.

AMP-Activated Protein Kinases↗
PubMed1997

CYP1A1, CYP2E1 and GSTM1 polymorphisms are not associated with susceptibility to squamous-cell carcinoma of the esophagus.

We investigated the genetic polymorphisms of CYP1A1, CYP2E1 and GSTM1 in Japanese esophageal cancer patients (n = 53) with a histological diagnosis of squamous-cell carcinoma, to determine whether susceptibility to esophageal cancer is associated with these polymorphisms. There were no significant differences in the frequency distribution of any one of the 3 polymorphisms between esophageal cancer patients and 132 healthy Japanese controls. The genotype distributions in tobacco smokers or alcohol drinkers were also quite similar for male patients and male controls. The age at onset of esophageal cancer was also similar for patients with any genotype of the 3 polymorphisms. We conclude that the 3 polymorphisms are unlikely to be associated with esophageal cancer susceptibility.

Adult↗
PubMed1997

Isolation and characterization of mouse nasal-associated lymphoid tissue.

A method for isolation of mouse nasal-associated lymphoid tissue (NALT), which is a principal mucosal lymphoid tissue of the respiratory tract in rodents, was developed. The paired lymphoid organs could be separated from the upper jaw by peeling away the palate where NALT was localized bilaterally on the posterior side. About 3 x 10(5) lymphocytes could be obtained from one NALT fragment. The NALT lymphocyte fraction from normal BALB/c mice contained T- and B-cells in about equal numbers, and contained about 4 times as many CD4+ T-cells as CD8+ T-cells when analyzed with a FACScan fluorescence analyzer. The composition of the NALT lymphocytes was similar to that of the lymphocytes from the portion of the nasal cavity remaining after isolation of the NALT. The NALT lymphocyte fraction from mice infected 7 days previously with influenza virus was also characterized. The numbers of NALT T- and B-cells from the infected mice were approximately 2 and 3 times higher than those of non-infected mice, respectively. In parallel with the cell increase, NALT lymphocytes produced IFN-gamma when cultured for 24 h and contained cells secreting influenza virus-specific IgA and IgG antibodies. The results suggest that this method can be successfully used for investigating cellular dynamics of mucosal immunology in the upper respiratory tract.

Animals↗
PubMed1997

Hard X-ray microbeam experiment at the Tristan main ring test beamline of the KEK.

A hard X-ray microbeam with zone-plate optics has been tested at the MR-BW-TL beamline on the Tristan main ring of the KEK, and preliminary experiments on scanning microscopy have also been performed. A sputtered-sliced Fresnel zone plate with an Au core and Ag/C multilayer is used as an X-ray focusing device. The outermost zone width of the zone plate is 0.25 microm. A focused spot size of approximately 0.5 mum has been achieved at an X-ray energy of 8.54 keV. In a scanning X-ray microscopy experiment, test patterns with submicrometer fine structure have been clearly resolved.

Journal Article↗