Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 19 recordsLinked to original sources

PubMed2007

A new technique for assaying cytochrome P450 enzyme activity in a single cell.

A new microspectrofluorometric technique for measuring the ethoxyresorufin-O-deethylase (EROD) activity of cytochrome P450 (CYP)1A1 in single living cells is described. The system, which uses a perfusion chamber and an HPLC pump, allowed cells to be stained, fixed, blocked, and washed by injecting each treatment solution into the on-line carrier stream of buffer from the sampling block of the HPLC pump. After addition of the substrate 7-ethoxyresorufin, the fluorescence intensity of the metabolite resorufin was measured in individual cells. Fluorescence intensity steeply increased to a unique peak for each cell and then decreased to the basal level. Furthermore, CYP1A1 in each cell was stained with its antibody and quantified using the fluorescence intensity of an FITC-conjugated secondary antibody. EROD activity was normalized using the FITC fluorescence. The results show that the initial slopes and peak values of resorufin production by the cells were dependent on the CYP1A1 level. Treatment of hepatocytes with two nonspecific P450 inhibitors, cimetidine and SKF-525A, suppressed EROD activity.

Animals↗

PubMed2006

Therapeutic RNA interference of malignant melanoma by electrotransfer of small interfering RNA targeting Mitf.

Microphthalmia-associated transcription factor (Mitf) is critically involved in melanin synthesis as well as differentiation of cells of the melanocytic lineage. Some earlier studies suggested that Mitf is also essential in the survival of melanoma cells, but this notion remains controversial. We synthesized short interfering RNA (siRNA) duplexes corresponding to the mitf sequence and transfected them into B16 melanoma. Lipid-mediated transfection in vitro of Mitf-specific siRNA resulted in specific downregulation of Mitf and of the tyrosinase that is a transcriptional target of Mitf. This treatment also remarkably reduced the viability of melanoma cells by inducing apoptosis. To examine the potential feasibility of RNAi therapy against melanoma, B16 cells were subcutaneously injected into syngenic mice and siRNA was transfected into the pre-established tumor by means of electroporation. The Mitf-specific siRNA drastically reduced outgrowth of subcutaneous melanoma, while nonspecific siRNA failed to affect tumor progression. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-based analysis of tumor specimens demonstrated that the tumor cells transfected with Mitf-siRNA effectively underwent apoptosis in vivo. The present results indicate that Mitf plays important roles in melanoma survival. Intratumor electrotransfer of Mitf-specific siRNA may provide a powerful strategy for therapeutic intervention of malignant melanoma.

Animals↗

PubMed2006

Influence of the progression of cryptococcal meningitis on brain penetration and efficacy of AmBisome in a murine model.

BACKGROUND: AmBisome is a small unilamellar vesicle containing amphotericin B. AmBisome is generally unable to pass through the blood-brain barrier, but the distribution of AmBisome in the brain is increased by inflammation, and in consequence, AmBisome exhibits activity against fungal meningitis. We investigated the influence of the progression of cryptococcal meningitis on the brain penetration and efficacy of AmBisome. METHOD: Mice were infected intracerebroventricularly with Cryptococcus neoformans 4 h or 5 days prior to a single dose treatment. RESULTS: The brain tissue level and efficacy of AmBisome when administered 5 days after infection were greater than 4 h after infection. An immunohistochemical study showed that AmBisome-derived amphotericin B was localized at the infected site in the subarachnoid space. When AmBisome was compared with Fungizone at the maximum tolerated dose, 10 mg/kg AmBisome exhibited greater efficacy than 1 mg/kg Fungizone in both regimens. CONCLUSION: The brain penetration of AmBisome was enhanced by the progression of cryptococcal meningitis and correlated with the in vivo activity.

Amphotericin B↗

PubMed2006

Measurement of acoustic output power in a traveling wave engine.

We built and tested a double-loop thermoacoustic cooler consisting of an engine-loop, a branch resonator, and a cooler-loop. The cooling power of 6.4 W was obtained at the cooling temperature of 0 degrees C, when the input heat power of 416 W was supplied to the engine-loop. We measured the acoustic power and found that the output power emitted from the engine-loop was 12 W, and that the input acoustic power entering the cooler-loop was 6 W.

Journal Article↗

PubMed2006

Near-infrared spectral results of asteroid Itokawa from the Hayabusa spacecraft.

The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth in the surface reflectance of asteroid 25143 Itokawa. Spectral shape over the 1-micrometer absorption band indicates that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites. Diversity in the physical condition of Itokawa's surface appears to be larger than for other S-type asteroids previously explored by spacecraft, such as 433 Eros.

Journal Article↗

PubMed2006

Phase separation in A-site-ordered perovskite manganite LaBaMn2O6 probed by 139La and 55Mn NMR.

139La- and 55Mn-NMR spectra demonstrate that the ground state of the A-site-ordered perovskite manganite LaBaMn2O6 is a spatial mixture of the ferromagnetic and antiferromagnetic regions, which are assigned to the metallic and the insulating charge ordered state, respectively. This exotic coexisting state appears below 200 K via a first-order-like formation of the antiferromagnetic charge ordered state inside the ferromagnetic metal one. The Mn spin-spin relaxation rate indicates that the ferromagnetic region coexisting with the antiferromagnetic one in LaBaMn2O6 is identical to the bulk ferromagnetic metal phase of the disordered form La0.5Ba0.5MnO3 in spite of the absence of A-site disorder. This suggests a mesoscopic rather than nanoscopic nature of the ferromagnetic region in LaBaMn2O6.

Journal Article↗

PubMed2006

Heavy-fermion-like state in a transition metal oxide LiV2O4 single crystal: indication of Kondo resonance in the photoemission spectrum.

We have performed a vacuum ultraviolet laser excited photoemission spectroscopy on a d-electron heavy-fermion-like material LiV2O4 single crystal. We observed a sharp peak structure in the density of states at approximately 4 meV above the Fermi level (E(F)). The evolution of the peak height corresponds well with the crossover behavior to the heavy-fermion-like state as observed in the thermal and transport properties. The position, shape, and temperature (T) dependence of the peak structure is quite similar to the Kondo resonance observed in conventional f-electron heavy Fermion compounds.

Journal Article↗

PubMed2006

Interferon-gamma is causatively involved in experimental inflammatory bowel disease in mice.

Cytokines may be crucially involved in the pathogenesis of inflammatory bowel diseases (IBD), but it remains controversial whether interferon (IFN)-gamma, a typical proinflammatory cytokine, is an essential mediator to cause the disorders. In the present study, IFN-gamma(-/-) and wild-type (WT) C57BL/6 mice were fed 2.5% dextran sodium sulphate (DSS) in drinking water for 7 days, in order to investigate DSS-induced intestinal inflammation. The DSS-treated WT mice exhibited a robust production of IFN-gamma in the gut, a remarkable loss of body weight, as well as high rate of mortality (60%). In striking contrast, IFN-gamma deficient mice did not develop DSS-induced colitis, as indicated by the maintenance of body weight and survival rate of 100%. Severe intestinal inflammation was demonstrated exclusively in WT animals in terms of the shortening of the bowel as well as the elevation of the disease activity index, myeloperoxidase (MPO) activity and serum haptoglobin level. Histological study of DSS-treated WT intestine revealed disruption of mucosal epithelium and massive infiltration of inflammatory cells, while the organ from IFN-gamma(-/-) mice remained virtually normal in appearance. Enzyme-linked immunosorbent assay (ELISA) analyses indicated abundant production of three chemokines, i.e. monokine induced by interferon-gamma (MIG), interferon-inducible protein 10 (IP-10) and monocyte chemoattractant protein-1 (MCP-1), in the DSS-irritated intestine of WT but not of IFN-gamma(-/-) mice. The present results demonstrate clearly that IFN-gamma plays indispensable roles in the initiation of DSS colitis, and some chemokines are produced in an IFN-gamma-dependent fashion.

Acute Disease↗

PubMed2006

Composite large cell neuroendocrine carcinoma and adenocarcinoma of the common bile duct.

Large cell neuroendocrine carcinoma (LCNEC) is a high grade type of neuroendocrine tumour with an aggressive clinical course. This report describes the first case of LCNEC combined with an adenocarcinoma component in the common bile duct. A 68 year old man presented with jaundice. Severe stenosis of the bile duct was revealed by endoscopic retrograde cholangiography, and adenocarcinoma cells were detected by brush cytology. Pancreaticoduodenectomy was performed, and the patient died of disease three months after surgery. A tumour measuring 2.0 cm in diameter was located in the intrapancreatic portion of the bile duct. Histologically, the tumour consisted of a LCNEC component and a well differentiated adenocarcinoma component. There were transitional areas between the two components. Immunohistochemically, LCNEC cells were reactive for neuroendocrine markers, but no specific hormonal expression was found. Chromogranin A positive cells were found in some areas of the adenocarcinoma component. These findings are consistent with the theory that both of the carcinoma components originated from a common pluripotent stem cell.

Adenocarcinoma↗

PubMed2006

Reactive lymphoid hyperplasia of the liver in a patient with multiple carcinomas: a case report and brief review.

A rare case of reactive lymphoid hyperplasia (RLH) of the liver in a 75-year-old woman admitted to hospital for surgical treatment of gastric, caecal and colon carcinomas is described here. Two nodular lesions in the left and right lobes of the liver were clinically diagnosed as metastatic tumours by computed tomography of the abdomen. A demarcating grey-white mass of size 1.4 cm was observed in a partially resected liver specimen. On examining the lesion microscopically, it was found to be composed of hyperplastic lymphoid follicles, lymphocytes, plasma cells, other inflammatory cells and interlaced hyalinised fibrous tissues. In the portal tracts around the lesion, chronic inflammatory cell infiltrates were seen, but no interface hepatitis or lymphoid follicle was observed. No evidence of monoclonality was observed by immunohistochemistry for B and T cell markers, in situ hybridisation for kappa and lambda light chains, and polymerase chain reaction analysis of immunoglobulin heavy chains or T cell receptor beta and gamma gene rearrangements. Bcl-2 immunoreactivity was not observed in the germinal centre. Epstein-Barr virus (EBV) antigen (latent membrane protein-1) and EBV-encoded small RNAs were not detected. A proliferation neither of myofibroblasts nor of cells positive for follicular dendritic cell markers was observed. RLH, formerly known as pseudolymphoma, has been reported of the liver in only 14 cases and is considered to be a differential diagnosis of small nodular lesions of the liver. That RLH has an inflammatory reactive nature, not a neoplastic disposition, and that EBV does not participate in the pathogenesis of RLH is supported by this case.

Adenocarcinoma↗

PubMed2006

Antigen clearing from porcine heart valves with preservation of structural integrity.

Bioprostheses currently used for replacement of diseased cardiovascular tissue are preserved and partially protected from immune rejection through chemical fixation. However, after implantation, chemically preserved (fixed) material has limited durability and lacks the ability to revitalize through cellular ingrowth and remodeling. As an alternative to fixation, we aimed at thoroughly removing antigens from tissue, leaving an intact scaffold, suitable for integration and revitalization in the host. Extensive washing of porcine heart valves with a mixture of two detergents (SDS and Triton X-100) yielded an intact matrix devoid of cells and depleted of soluble proteins that was minimally immunogenic in rabbits. A detailed characterization of the biomechanics and durability of the tissue is under way. If the lack of immunogenicity is confirmed in primates, our results would suggest that a detergent-washed, unfixed porcine heart valve can be an attractive non-inflammatory scaffold for heart valve regeneration in humans.

Animals↗

PubMed2006

Urinary liver-type fatty acid-binding protein levels for differential diagnosis of idiopathic focal glomerulosclerosis and minor glomerular abnormalities and effect of low-density lipoprotein apheresis.

AIMS: Focal glomerulosclerosis (FGS) and minor glomerular abnormalities are kidney diseases characterized by massive proteinuria. Urinary liver-type fatty acid-binding protein (L-FABP), an intracellular carrier protein of free fatty acids, is expressed in proximal tubules of the human kidney. Patients with FGS show significant improvement with low-density lipoprotein (LDL) apheresis. The aim of the present study was to determine whether urinary L-FABP levels differ between patients with FGS and those with minor glomerular abnormalities and whether levels are altered by LDL apheresis. PATIENTS AND METHODS: There were 24 patients with minor glomerular abnormalities (nephrotic stage, n = 14, remission stage, n = 10), 17 patients with FGS, and 20 healthy age-matched subjects were included in the present study. Urinary L-FABP levels were measured by enzyme-linked immunosorbent assay and compared. All patients with minor glomerular abnormalities at the nephrotic stage received prednisolone for 6 months, and all FGS patients received some form of immunosuppression therapy with prednisolone, cyclophosphamide or mizoribine for 12 months. LDL apheresis was performed in eight FGS patients with drug-resistant nephrotic syndrome. RESULTS: Urinary L-FABP levels were significantly higher in the 17 FGS patients (82.0 +/- 44.4 microg/g.Cr) than in the 24 patients with minor glomerular abnormalities (10.2 +/- 8.4 microg/g.Cr) (p < 0.01) and in the 20 healthy subjects (7.4 +/- 4.2 microg/g.Cr) (p < 0.01). Urinary L-FABP levels differed little between nephrotic stage and remission stage in patients with minor glomerular abnormalities. Urinary L-FABP levels were significantly higher in the eight drug-resistant FGS patients (122.6 +/- 78.4 microg/g.Cr) than in the nine drug-sensitive FGS patients (45.9 +/- 32.0 microg/g.Cr). Urinary L-FABP levels did not correlate with levels of other clinical markers including serum creatinine, urinary protein, and urinary N-acetyl-beta-D- glucosaminidase. In the eight drug-resistant FGS patients, LDL-apheresis significantly reduced urinary protein excretion (p < 0.01) and urinary L-FABP levels (p < 0.01). CONCLUSIONS: Urinary L-FABP may be a useful diagnostic indicator for differentiation between FGS and minor glomerular abnormalities. LDL apheresis may be effective in ameliorating tubulointerstitial lesions associated with FGS.

Adult↗

PubMed2006

[Aortic valve replacement for the small aortic annulus].

Aortic valve surgery for the small aortic annulus is still challenging for surgeons. Recently, the new types of high performance prosthesis have been developed and the chance of an aortic root enlargement (ARE) is decreasing. In this study, we propose the ideal strategy of the aortic surgery for the small aortic annulus. We analyzed the clinical records of 158 patients who underwent aortic valve replacement from August 1999 to October 2005 in our institution. The small aortic annulus was observed in 38 patients (24%). Fourteen patients of this group underwent ARE. Patient-prosthesis mismatch (PPM) was less frequently observed in patients with ARE compared to those without ARE. The additional time required for ARE was not considerable, and neither ischemic time nor cardiopulmonary bypass time was significantly prolonged by ARE. In conclusion, we have to select a prosthesis with sufficient orifice area to avoid PPM, otherwise we should choose an option of ARE. For this consideration, we definitely need the chart that demonstrates the relationship between the nominal size of various types of prostheses and the size of a patient's annulus that those prostheses actually fit.

Aged↗

PubMed2005

Oxidative stress by glutathione depletion induces osteonecrosis in rats.

OBJECTIVE: We recently implicated in vivo oxidative stress in the development of osteonecrosis in a steroid-induced osteonecrosis model in the domestic rabbit. In the present experiment we devised a new non-traumatic model using the rat to investigate the relationship between oxidative stress and the development of osteonecrosis. METHODS: Seven 24-week-old male Wistar rats were subcutaneously injected with the pro-oxidant buthionine sulphoximine (BSO) 500 mg/kg for 14 consecutive days (group B) and eight rats received injections of vehicle (physiological saline; group N). The rats in both groups were killed after 14 days, and their bilateral femurs were examined histopathologically. Blood levels of reduced glutathione (GSH), total cholesterol (T-cho) and triglycerides (TG) were also determined. RESULTS: GSH was significantly decreased in group B compared with group N (P < 0.01). No significant differences were found in T-cho or TG. Osteonecrosis was not detected in any animal in group N in contrast to five of seven animals in group B (P < 0.05). CONCLUSION: BSO is an inducer of oxidative stress, in particular interfering with the synthesis of GSH in vivo. In the present study, GSH levels were markedly reduced by BSO, whereas neither T-cho nor TG was significantly changed. The high rate of osteonecrosis noted in group B suggests that oxidative stress alone may be sufficient to promote the development of osteonecrosis at certain sites.

Animals↗

PubMed2005

Anomalous magnetic properties near the spin-flop bicritical point in Mn(2)AS(4) (A = Si and Ge).

The magnetic properties of the single crystalline Mn(2)AS(4) (A = Si and Ge) with an olivine structure, which are the uniaxially anisotropic antiferromagnets (the b axis as an easy axis), were investigated. Near the Néel temperature, both compounds exhibit the contrastive magnetic responses along the c axis, namely, the spontaneous weak ferromagnetism in A = Si and the significant enhancement of the differential susceptibility (dM/dH) under the small magnetic field in A = Ge. When A = Ge, we also observed the evolution of dM/dH along the axis at low temperatures. We discuss these phenomena on the basis of the magnetic field-temperature (H-T) phase diagram with the spin-flop bicritical point (H(BP), T(BP). The role of the thermal or quantum fluctuation was stressed.

Journal Article↗

PubMed2005

Serial changes in plasma brain natriuretic peptide concentration at the infarct and non-infarct sites in patients with left ventricular remodelling after myocardial infarction.

OBJECTIVES: To clarify the role of infarct and non-infarct sites on left ventricular (LV) remodelling after myocardial infarction by measuring brain natriuretic peptide (BNP) from each site. METHODS AND RESULTS: BNP from the aorta and the anterior interventricular vein (AIV) was measured in 45 patients with first anterior myocardial infarction at one, six, and 18 months. The LV was significantly dilated (> 10 ml/m(2) of end diastolic volume from one to 18 months) in 20 patients (remodelling (R) group) but not in 25 others (non-remodelling (NR) group). Patient characteristics and LV functions did not differ significantly at one month but plasma BNP concentration was higher in group R than in group NR (336 (288) v 116 (106) pg/ml, p < 0.01), predicting the degree of LV dilatation. The difference in BNP concentration between the aortic root and AIV (DeltaBNP), reflecting BNP secreted from the infarct site, did not differ at one month. In both groups BNP and DeltaBNP significantly decreased from one to six months (p < 0.05) and decreased from six months to 18 months, but the change was not significant. BNP and DeltaBNP were significantly higher in group R than in group NR after six months, when LV dilatation was not evident in both groups. CONCLUSION: Enhanced BNP secretion at one month in the non-infarct and infarct ventricular sites predicts subsequent LV dilatation (that is, remodelling). The slower process of LV remodelling decreased BNP secretion at both sites. Thus, BNP concentration should be useful for monitoring ventricular remodelling after infarction.

Cardiomyopathy, Dilated↗

PubMed2005

Pigmented cutaneous papillomatosis (pigmented epidermal nevus) in three pug dogs; histopathology, electron microscopy and analysis of viral DNA by the polymerase chain reaction.

Canine pigmented epidermal nevus (CPEN) is a skin disorder of some breeds of dog characterized by multiple black plaques of the haired and non-haired skin. Three cases of pigmented cutaneous papillomatosis (previously described also as CPEN) in pug dogs were investigated histopathologically, immunohistochemically and electron microscopically. Additionally, DNA analyses with the polymerase chain reaction (PCR) were performed in two cases. Many nuclei of the stratum granulosa were diffusely immunolabelled for specific structural antigens of bovine papillomavirus (subgroup A), but nuclear inclusion bodies were not detected by retrospective examination of haematoxylin and eosin-stained sections of the affected skin. Aggregates of small numbers of viral particles (ranging from 37 to 43 nm in diameter) with a hexagonal structure were sparsely scattered throughout the nuclei of some of the superficial keratinocytes. PCR amplification targeted for the L1 gene of papillomavirus cloned from a case of CPEN yielded an expected fragment of 194-bp in the two CPEN cases examined but not in a case of canine oral papilloma.

Animals↗

PubMed2005

Reduced-intensity stem-cell transplantation for adult acute lymphoblastic leukemia: a retrospective study of 33 patients.

Efficacy of reduced-intensity stem-cell transplantation (RIST) for acute lymphoblastic leukemia (ALL) was investigated in 33 patients (median age, 55 years). RIST sources comprised 20 HLA-identical related donors, five HLA-mismatched related, and eight unrelated donors. Six patients had undergone previous transplantation. Disease status at RIST was first remission (n=13), second remission (n=6), and induction failure or relapse (n=14). All patients tolerated preparatory regimens and achieved neutrophil engraftment (median, day 12.5). Acute and chronic graft-versus-host disease (GVHD) developed in 45 and 64%, respectively. Six patients received donor lymphocyte infusion (DLI), for prophylaxis (n=1) or treatment of recurrent ALL (n=5). Nine patients died of transplant-related mortality, with six deaths due to GVHD. The median follow-up of surviving patients was 11.6 months (range, 3.5-37.3 months). The 1-year relapse-free and overall survival rates were 29.8 and 39.6%, respectively. Of the 14 patients transplanted in relapse, five remained relapse free for longer than 6 months. Cumulative rates of progression and progression-free mortality at 3 years were 50.9 and 30.4%, respectively. These findings suggest the presence of a graft-versus-leukemia effect for ALL. RIST for ALL is worth considering for further evaluation.

Adolescent↗