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Biomedical subjects

Y Matsuda

Publications and source records attributed to Y Matsuda.

At least 19 recordsLinked to original sources
PubMed2003

Antiferromagnetic vortex core in Tl(2)Ba(2)CuO(6+delta) studied by nuclear magnetic resonance.

Spatially resolved NMR is used to probe the magnetism in and around vortex cores of nearly optimally doped Tl(2)Ba(2)CuO(6+delta) (T(c)=85 K). The NMR relaxation rate T(-1)1 at the 205Tl site provides direct evidence that the antiferromagnetic (AF) spin correlation is significantly enhanced in the vortex core region. In the core region Cu spins show a local AF ordering with moments parallel to the layers at T(N)=20 K. Above T(N) the core region is in the paramagnetic state which is a reminiscence of the state above the pseudogap temperature (T(*) approximately 120 K), indicating that the pseudogap disappears within cores.

Journal Article↗
PubMed2003

Multiple superconducting phases in new heavy fermion superconductor PrOs4Sb12.

The superconducting gap structure of recently discovered heavy fermion superconductor PrOs4Sb12 was investigated by using thermal transport measurements in magnetic field rotated relative to the crystal axes. We demonstrate that a novel change in the symmetry of the superconducting gap function occurs deep inside the superconducting state, giving a clear indication of the presence of two distinct superconducting phases with twofold and fourfold symmetries. We infer that the gap functions in both phases have a point node singularity, in contrast to the familiar line node singularity observed in almost all unconventional superconductors.

Journal Article↗
PubMed2003

Discovery of temperature-dependent phenomena of muon-catalyzed fusion in solid deuterium and tritium mixtures.

A systematic experimental study on muon-catalyzed fusion was conducted using a series of solid deuterium and tritium mixtures. A variety of conditions were investigated, i.e., tritium concentrations from 20% to 70%, and temperatures from 5 to 16 K. With decreasing temperature, we observed an unexpected decrease in the muon cycling rate (lambda(c)) and an increase in the muon loss probability (W). The origins of these observed changes were interpreted by the temperature-dependence in the dt mu formation process for lambda(c) and that in the muon reactivation process after muon-to-alpha sticking for W.

Journal Article↗
PubMed2003

Non-contact sound velocities and attenuation measurements of several ceramics at elevated temperatures.

Laser ultrasonic technique has been employed to carry out the sound velocities and attenuation measurements as a function of temperature in alumina, two kinds of silicon nitride and partially stabilized zirconia (PSZ) samples. Accuracy of the laser technique used has been checked in terms of the diffraction effect and reproducibility of the results. Results of attenuation at room temperature have been compared with quartz transducer technique. In PSZ, velocity behavior has become non-linear and also, a peak in attenuation has been observed around 500 degrees C. In one of the silicon nitride sample, which uses glassy sintering agent, attenuation has shown a sharp peak around 950 degrees C. Interestingly, when the experiment was repeated from 800 to 1000 degrees C, this anomalous attenuation peak has disappeared, leaving a background increasing towards higher temperatures.

Journal Article↗
PubMed2003

Association between K469E allele of intercellular adhesion molecule 1 gene and inflammatory bowel disease in a Japanese population.

BACKGROUND AND AIMS: The genetic contribution to inflammatory bowel disease (IBD) is under investigation. Recent evidence indicates a significant linkage between a locus on chromosome 19p13 and IBD. We investigated the association between an intercellular adhesion molecule 1 gene (ICAM-1) polymorphism located on chromosome 19p13 and IBD in a Japanese population. METHODS: We compared 207 Japanese patients who had IBD (79 with Crohn's disease (CD); 128 with ulcerative colitis (UC)) with 103 unrelated Japanese controls. We determined R241G and K469E polymorphisms of the ICAM-1 gene using polymerase chain reaction (PCR) techniques. RESULTS: Both frequency and carriage rate of the K469 allele were significantly higher in IBD patients than in controls (allelic frequency, p(c)=0.0026; carriage rate, p(c)=0.0034; odds ratio 2.59; 95% confidence interval 1.42-4.68). Furthermore, the frequency of the K469 allele was significantly increased in both CD and UC. Subgroup analysis demonstrated that both K469 allelic frequency and K469 carriage rate were significantly higher in patients with the small bowel and colon type of CD and entire colitis compared with healthy controls. CONCLUSIONS: We identified an overall association between IBD and ICAM-1 K469 in a Japanese population. Further studies of this chromosome region are required to elucidate the gene responsible for IBD.

Adolescent↗
PubMed2002

Gap function with point nodes in borocarbide superconductor YNi2B2C.

To determine the superconducting gap function of YNi2B2C, the c-axis thermal conductivity kappa(zz) was measured in H rotated in various directions. The angular variation of kappa(zz) in H rotated within the ab plane shows a peculiar fourfold oscillation with narrow cusps. The amplitude of this fourfold oscillation becomes very small when H is rotated conically around the c axis with a tilt angle of 45 degrees. These results provide the first compelling evidence that the gap function has point nodes located along the a and b axes. This unprecedented gap structure challenges the current view on the pairing mechanism.

Journal Article↗
PubMed2002

Ganciclovir is effective for prophylaxis and treatment of human herpesvirus-6 in allogeneic stem cell transplantation.

Human herpesvirus 6 (HHV-6) infection and disease are serious complications of allogeneic hematopoietic stem cell transplantation (allo-SCT). Ganciclovir (GCV) is effective against HHV-6 in vitro but the antiviral susceptibility of HHV-6 has not been well characterized in vivo. We retrospectively compared the HHV-6 reactivation rate in pediatric allo-SCT recipients with and without GCV prophylaxis. The HHV-6 reactivation rate at 3 weeks after allo-SCT in patients without prophylactic GCV administration was significantly higher than that in those receiving prophylactic GCV (11/28 vs 0/13, P < 0.01). Five of 36 patients without prophylactic GCV showed clinical manifestations including skin rash, interstitial pneumonitis, persistent thrombocytopenia, enterocolitis and thrombotic microangiopathy, respectively. HHV-6-associated symptoms were observed in one of the 13 patients receiving prophylactic GCV. This patient showed fever, diarrhea and graft rejection concomitantly with a sudden increase of HHV-6 DNA copy number. Patients who received GCV for treatment of HHV-6 infection showed an improvement in symptoms and/or decrease of HHV-6 copy number. Thus, GCV is effective for treating HHV-6 disease after allo-SCT in vivo.

Antiviral Agents↗
PubMed2002

Tyrosine 759 of the cytokine receptor gp130 is involved in Listeria monocytogenes susceptibility.

Interleukin-6 family cytokines have been implicated in adaptive and innate immunity, hematopoiesis, and inflammation. This cytokine family shares a signal-transducing receptor subunit called gp130. gp130(F759/F759) knockin mice carry a point mutation at the SHP2-binding site of gp130 due to the replacement of tyrosine-759 (Y759 for human gp130) with phenylalanine (F). To explore the effect of this point mutation on the host response to bacterial infection, gp130(F759/F759) knockin mice were infected with Listeria monocytogenes. gp130(F759/F759) knockin mice began to die at 3 to 4 days post infection (p.i.) and showed higher mortality than did controls. Listeria titers at 3 days p.i. in the peritoneal cavity, spleen, and liver were significantly higher in gp130(F759/F759)knockin mice than in controls. Nitric oxide production, upregulation of the mRNA levels of a variety of cytokines, and listericidal activity in gp130(F759/F759) macrophages were unchanged. However, gp130(F759/F759) knockin mice displayed significantly lower levels of interferon (IFN)gamma in serum and in the culture supernatant from peritoneal exudate cells and splenocytes, in response to Listeria infection. These results suggest that the Y759 point mutation in gp130 attenuates the early phase of defense against Listeria infection, possibly owing to insufficient elevation of IFNgamma levels, and thus gp130 is a possible candidate gene for Listeria susceptibility.

Animals↗
PubMed2002

Rapid detection of phylloplane bacterium Enterobacter cloacae based on chitinase gene transformation and lytic infection by specific bacteriophages.

AIMS: To establish a rapid and efficient method for detecting Enterobacter cloacae based on chitinase gene transformation and lytic infection by virulent bacteriophages. METHODS AND RESULTS: A phylloplane strain of E. cloacae was isolated from tomato leaves and transformed with a chitinase gene. Transformed bacteria were collected from single colonies and infected with newly isolated, virulent bacteriophages in the presence of the chitinase substrate 4-methylumbelliferon (4MU)-(GlcNac)3. To assay chitinase activity in the lysates, the product 4MU was measured spectrofluorophotometrically or visibly detected under u.v. irradiation. Chitinase gene-transformed bacteria obtained from single colonies could be specifically identified in 30 min by the emission of 4MU fluorescence following lysis caused by phage infection. CONCLUSIONS: The chitinase gene was used as a reporter gene to construct a new system for easy and rapid monitoring of transgenic strains of E. cloacae released in the environment, in combination with specific recognition by virulent bacteriophages. SIGNIFICANCE AND IMPACT OF THE STUDY: The assay is simple, rapid, inexpensive, easy to perform and applicable to other strains. The system can be used for the routine monitoring of bacteria, which is important because of the increased use of transgenic strains of E. cloacae as an antagonistic biological control agent for plant diseases.

Bacteriophage Typing↗
PubMed2002

Chromosome assignment of eight SOX family genes in chicken.

Chromosome locations of the eight SOX family genes, SOX1, SOX2, SOX3, SOX5, SOX9, SOX10, SOX14 and SOX21, were determined in the chicken by fluorescence in situ hybridization. The SOX1 and SOX21 genes were localized to chicken chromosome 1q3.1-->q3.2, SOX5 to chromosome 1p1.6-->p1.4, SOX10 to chromosome 1p1.6, and SOX3 to chromosome 4p1.2-->p1.1. The SOX2 and SOX14 genes were shown to be linked to chromosome 9 using two-colored FISH and chromosome painting, and the SOX9 gene was assigned to a pair of microchromosomes. These results suggest that these SOX genes form at least three clusters on chicken chromosomes. The seven SOX genes, SOX1, SOX2, SOX3, SOX5, SOX10, SOX14 and SOX21 were localized to chromosome segments with homologies to human chromosomes, indicating that the chromosome locations of SOX family genes are highly conserved between chicken and human.

Animals↗
PubMed2002

Chromosome rearrangements between chicken and guinea fowl defined by comparative chromosome painting and FISH mapping of DNA clones.

Chromosome homology between chicken (Gallus gallus) and guinea fowl (Numida meleagris) was investigated by comparative chromosome painting with chicken whole chromosome paints for chromosomes 1-9 and Z and by comparative mapping of 38 macrochromosome-specific (chromosomes 1-8 and Z) and 30 microchromosome-specific chicken cosmid DNA clones. The comparative chromosome analysis revealed that the homology of macrochromosomes is highly conserved between the two species except for two inter-chromosomal rearrangements. Guinea fowl chromosome 4 represented the centric fusion of chicken chromosome 9 with the q arm of chicken chromosome 4. Guinea fowl chromosome 5 resulted from the fusion of chicken chromosomes 6 and 7. A pericentric inversion was found in guinea fowl chromosome 7, which corresponded to chicken chromosome 8. All the chicken microchromosome-specific DNA clones were also localized to microchromosomes of guinea fowl except for several clones localized to the short arm of chromosome 4. These results suggest that the cytogenetic genome organization is highly conserved between chicken and guinea fowl.

Animals↗
PubMed2002

Molecular cloning and characterization of novel centromeric repetitive DNA sequences in the blue-breasted quail (Coturnix chinensis, Galliformes).

A new family of centromeric highly repetitive DNA sequences was isolated from EcoRI-digested genomic DNA of the blue-breasted quail (Coturnix chinensis, Galliformes), and characterized by filter hybridization and chromosome in situ hybridization. The repeated elements were divided into two types by nucleotide length and chromosomal distribution; the 578-bp element predominantly localized to microchromosomes and the 1,524-bp element localized to chromosomes 1 and 2. The 578-bp element represented tandem arrays and did not hybridize to genomic DNAs of other Galliformes species, chicken (Gallus gallus), Japanese quail (Coturnix japonica) and guinea fowl (Numida meleagris). On the other hand, the 1,524-bp element was not organized in tandem arrays, and did hybridize to the genomic DNAs of three other Galliformes species, suggesting that the 1,524-bp element is highly conserved in the Galliformes. The 578-bp element was composed of basic 20-bp internal repeats, and the consensus nucleotide sequence of the internal repeats had homologies to the 41-42 bp CNM repeat and the XHOI family repeat of chicken. Our data suggest that the microchromosome-specific highly repetitive sequences of the blue-breasted quail and chicken were derived from a common ancestral sequence, and that they are one of the major and essential components of chromosomal heterochromatin in Galliformes species.

Animals↗
PubMed2002

X-chromosomal localization of mammalian Y-linked genes in two XO species of the Ryukyu spiny rat.

Ryukyu spiny rats (genus Tokudaia), which are endemic to the central part of the Nansei Shoto archipelago in Japan, have unique karyotypes with odd numbers of chromosomes and no cytologically recognizable Y chromosome. The chromosome numbers of Tokudaia osimensis from Amamioshima and of Tokudaia sp. from Tokunoshima are 2n = 25 and 2n = 45, respectively, with a putative single X chromosome. The mouse X probe hybridized to the unpaired X chromosome, except for the distal part of the short arm in a female specimen of T. osimensis and in one male and one female of Tokudaia sp. Fluorescence in situ hybridization with the Tspy (testis-specific protein, Y-encoded) gene from both male and female cells of Tokudaia sp. by PCR localized Tspy to the distal part of the long arm of the X chromosome. Another Y-related gene, Zfy, from Tokudaia sp. was also localized to the same region in both species. Although the Sry gene is absent in this species, the present results suggest that the Y-chromosome segment carrying functional Y-linked genes, such as Tspy and Zfy, is translocated onto the distal part of the long arm of the X chromosome.

Animals↗
PubMed2002

Biallelic expression of Z-linked genes in male chickens.

In birds, females are heterogametic (ZW), while males are homogametic (ZZ). It has been proposed that there is no dosage compensation for the expression of Z-linked genes in birds. In order to examine if the genes are inactivated on one of the two Z chromosomes, we analyzed the allelic expression of the B4GALT1 and CHD-Z genes on Z chromosomes in male chickens. One base substitution was detected among 15 chicken breeds and lines examined for each gene, and cross mating was made between the breeds or lines with polymorphism. cDNAs were synthesized from cultured cell colonies each derived from a single cell of an F1 male embryo. The allelic expression of the B4GALT1 gene was examined by restriction fragment length polymorphism analysis of the PCR products digested with RSAI, and that of the CHD-Z gene by the single nucleotide primer extension (SNuPE) method. Both of the genes displayed biallelic expression, suggesting that these Z-linked genes were not subject to inactivation in male chickens. Comparison between expression levels in males and females by real-time quantitative PCR suggested that expression was compensated for the CHD-Z gene but not for the B4GALT1 gene.

Alleles↗
PubMed2001

Proprotein convertase PACE4 is down-regulated by the basic helix-loop-helix transcription factor hASH-1 and MASH-1.

PACE4 is a mammalian subtilisin-like proprotein convertase that activates transforming growth factor (TGF)-beta-related proteins such as bone morphogenetic protein 2 (BMP2), BMP4 and Nodal and exhibits a dynamic expression pattern during embryogenesis. We recently determined that the 1 kb 5'-upstream region of the PACE4 gene contains 12 E-box (E1-E12) elements and that an E-box cluster (E4-E9) acts as a negative regulator [Tsuji, Yoshida, Hasegawa, Bando, Yoshida, Koide, Mori and Matsuda (1999) J. Biochem. (Tokyo) 126, 494-502]. It is known that the mammalian achaete-scute homologue 1 (MASH-1) binds specifically to an E-box (CACCTG) sequence in collaboration with E47, a ubiquitously expressed basic helix-loop-helix (bHLH) factor. To identify the roles of the bHLH factor and E-box elements in regulating PACE4 gene expression in neural development, we analysed the effects of human achaete-scute homologue 1 (hASH-1) on PACE4 gene expression with various neuroblastoma cell lines. The expressions of PACE4 and hASH-1 are correlated inversely in these cell lines. The overexpression of hASH-1 or MASH-1 causes a marked decrease in endogenous PACE4 gene expression but has no effect on the expression of other subtilisin-like proprotein convertases such as furin, PC5/6 and PC7/8. In contrast, other neural bHLH factors (MATH-1, MATH-2, neurogenin 1, neurogenin 2, neurogenin 3 and E47) did not affect PACE4 gene expression. Furthermore, an E-box cluster was a negative regulatory element for the promoter activity in NBL-S cells expressing hASH-1 at high level as determined by a luciferase assay. Binding of hASH-1 to the E-box cluster was confirmed by gel mobility-shift assay. In the present study we identified the PACE4 gene as one of the targets of hASH-1, which is a key factor in the initiation of neural differentiation. These results suggest that the alteration of PACE4 gene expression by hASH-1 causes rapid changes in the biological activities of TGF-beta-related proteins via post-translational modification of these proteins.

Basic Helix-Loop-Helix Proteins↗
PubMed2001

Mice lacking Ca(v)2.3 (alpha1E) calcium channel exhibit hyperglycemia.

To investigate the functional role of Ca(v)2.3 channel in glucose homeostasis, we performed in vivo glucose tolerance and insulin tolerance tests together with stress-induced glucose release tests using mice deficient in Ca(v)2.3 channel (Ca(v)2.3-/-). The Ca(v)2.3-/- mice were significantly heavier than wild-type mice. In glucose tolerance and insulin tolerance tests, Ca(v)2.3-/- mice showed a significantly higher blood glucose level compared to wild-type mice. However, stress-induced blood glucose changes in Ca(v)2.3-/- mice were similar to those in wild-type mice. These results suggest that Ca(v)2.3 channel plays a role in glucose homeostasis by reducing insulin sensitivity and that Ca(v)2.3-/- mice exhibit symptoms resembling non-insulin-dependent diabetes mellitus.

Animals↗
PubMed2001

Cloning, genomic structure and chromosomal localization of the gene encoding mouse DNA helicase RECQL5beta.

Five members of the RecQ helicase family, RECQL, WRN, BLM, RTS and RECQL5, have been found in human and three of them (WRN, BLM and RTS) were disclosed to be the genes responsible for Werner, Bloom and Rothmund-Thomson syndromes, respectively. RECQL5 (RecQ helicase protein-like 5) was isolated as the fifth member of the family in humans through a search of homologous expressed sequence tags. The gene is expressed with at least three alternative splicing products, alpha, beta and gamma. Here, we isolated mouse RECQL5 beta and determined the DNA sequence of full-length cDNA as well as the genome organization and chromosome locus. The mouse RECQL5 beta gene consists of 2949 bp coding 982 amino acid residues. Comparison of amino acid sequence among human (Homo sapiens), mouse (Mus musculus), Drosophila melanogaster and Caenorhabditis elegans RECQL5 beta homologs revealed three portions of highly conserved regions in addition to the helicase domain. Nineteen exons are dispersed over 40 kbp in the genome and all of the acceptor and donor sites for the splicing of each exon conform to the GT/AG rule. The gene is localized to the mouse chromosome 11E2, which has a syntenic relation to human 17q25.2-q25.3 where human RECQL5 beta exists. Our genetic characterizations of the mouse RECQL5 beta gene will contribute to functional studies on the RECQL5 beta products.

Amino Acid Sequence↗