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Biomedical subjects

H Yamane

Publications and source records attributed to H Yamane.

At least 37 records · Page 2Linked to original sources
PubMed2000

Identification of novel metabolites in the degradation of phenanthrene by Sphingomonas sp. strain P2.

Sphingomonas sp. strain P2, which is capable of utilizing phenanthrene as a sole carbon and energy source, was isolated from petroleum-contaminated soil in Thailand. Gas chromatography-mass spectrometry and (1)H and (13)C nuclear magnetic resonance analyses revealed two novel metabolites from the phenanthrene degradation pathway. One was identified as 5,6-benzocoumarin, which was derived by dioxygenation at the 1- and 2-positions of phenanthrene, and the other was determined to be 1,5-dihydroxy-2-naphthoic acid. Other metabolites from phenanthrene degradation were identified as 7, 8-benzocoumarin, 1-hydroxy-2-naphthoic acid and coumarin. From these results, it is suggested that strain P2 can degrade phenanthrene via dioxygenation at both 1,2- and 3,4-positions followed by meta-cleavage.

Biodegradation, Environmental↗
PubMed2000

Role of the rasGAP-associated docking protein p62(dok) in negative regulation of B cell receptor-mediated signaling.

Antigenic stimulation of the B-cell receptor (BCR) is a central event in the immune response. In contrast, antigen bound to IgG negatively regulates signals from the BCR by cross-linking it to the inhibitory receptor FcgammaRIIB. Here we show that upon cross-linking of BCR or BCR with FcgammaRIIB, the rasGAP-associated protein p62(dok) is prominently tyrosine phosphorylated in a Lyn-dependent manner. Inactivation of the dok gene by homologous recombination has shown that upon BCR cross-linking, p62(dok) suppresses MAP kinase and is indispensable for FcgammaRIIB-mediated negative regulation of cell proliferation. We propose that p62(dok), a downstream target of many PTKs, plays a negative role in various signaling situations.

Animals↗
PubMed2000

Positive and negative regulation of IL-12 receptor expression of naive CD4(+) T cells by CD28/CD152 co-stimulation.

IL-12 is a critical cytokine for polarizing naive CD4(+) T cells toward Th1 subset. Therefore, it is important to elucidate the mechanism of IL-12R expression of naive CD4(+) T cells. In this report, we present evidence to show that expression of both IL-12Rbeta1 and beta2 mRNA is regulated by signals mediated through CD28 and CD152. Naive CD4(+) T cells stimulated with anti-CD3 alone neither expressed IL-12Rbeta2 mRNA nor bound detectable level of rIL-12, although they expressed a very low level of IL-12Rbeta1 mRNA when stimulated with a high dose of anti-CD3. Expression of IL-12Rbeta1 and beta2 mRNA was induced by the co-ligation of CD3 and CD28, and it was down-regulated by the ligation of CD152. CD28 ligation induced not only IL-12Rbeta1 and beta2 mRNA expression, but also enhanced IFN-gammaR to mediate up-regulation of IL-12R by IFN-gamma.

Abatacept↗
PubMed2000

Saccharide production from methanol by transposon 5 mutants derived from the extracellular polysaccharide-producing bacterium Methylobacillus sp. strain 12S.

A CH3OH-utilizing bacterium that has the ability to produce extracellular polysaccharide (EPS) was isolated from a soil sample, and was identified as the obligate methylotroph Methylobacillus sp. strain 12S on the basis of its 16S rDNA sequence and growth-substrate specificity. The EPS produced by strain 12S was purified and the sugar composition was analysed by GC-MS and HPLC to reveal that the EPS was a heteropolymer composed of glucosyl, galactosyl, and mannosyl residues in the molar ratio 3:1:1. In order to produce mono- and/or oligosaccharides by single-step fermentation from CH3OH, stain 12S was mutagenized by transposon 5. Among eleven EPS-deficient mutants, three strains were found to accumulate significant amounts of reducing sugars in the media. The amounts of the reducing sugars produced by the mutants ( > ca. 700 mg glucose equivalent/l) were > 11-22 times higher than those produced by the wild-type strain (<ca. 60 mg glucose equivalent/l). The GC-MS analysis showed that all the mutants accumulated glucose, erythrose, threose and a disaccharide-like compound in the media.

Chromatography, High Pressure Liquid↗
PubMed1999

Cytochrome c redistribution in apoptosis of guinea pig vestibular hair cells.

We examined the cellular location of cytochrome c in healthy and in streptomycin-damaged vestibular hair cells by immunohistochemistry. Staining for cytochrome c revealed an immunostain pattern that was consistent with a mitochondrial distribution of this enzyme in healthy hair cells, while in hair cells affected by aminoglycosides, a diffuse distribution in the cytoplasm was found together with apoptotic nuclear morphology. These findings suggest that redistribution of cytochrome c is involved in the pathway of apoptosis in vestibular hair cells induced by aminoglycosides.

Animals↗
PubMed1999

Effective stimulation for IL-12 p35 mRNA accumulation and bioactive IL-12 production of antigen-presenting cells interacted with Th cells.

Bioactive IL-12 is composed of two subunits, p35 and p40. In the APC-Th cell interaction, p40 mRNA accumulation in APC was shown to be up-regulated by stimulation with CD40 ligand (CD40L) on Th cells. However, the CD40-CD40L interaction scarcely induced p35 mRNA accumulation in APC. In the present experiments, p35 mRNA accumulation was induced in splenic macrophages/dendritic cells by the interaction with paraformaldehyde-fixed Th1 cells in the presence of Ag, and the p35 mRNA accumulation was abrogated by the inclusion of anti-I-A in cultures to block TCR/MHC class II interaction. The accumulation was also induced by the stimulation with agonistic anti-I-A. These results indicate that the interaction of the MHC class II molecule with TCR evokes an activation signal for p35 mRNA accumulation in APC. Furthermore, the production of bioactive IL-12 in macrophages/dendritic cells stimulated with CD40L was enhanced by the inclusion of agonistic anti-I-A. The p35 mRNA accumulation and IL-12 production of macrophages/dendritic cells induced by stimulation with OVA-specific fixed Th1 clone expressing CD40L were also enhanced by adding OVA in cultures. These results indicate that the p35 mRNA accumulation induced by MHC class II stimulation plays a role in bioactive IL-12 production.

Animals↗
PubMed1999

Involvement of nitric oxide in aminoglycoside vestibulotoxicity in guinea pigs.

Involvement of nitric oxide (NO) has been reported in physiological and pathological conditions in the inner ear. Recently, the presence of nitric oxide synthase (NOS) was demonstrated in the vestibular epithelium. In this study we used nicotinamide adenine dinucleotide phosphate-diapholase staining to monitor NOS activity during degeneration of guinea pig vestibular epithelia affected by streptomycin. Increased NOS activity was observed in affected epithelia in a dose- and time-dependent manner and a NOS inhibitor could protect hair cells from apoptosis. Additionally, cycloheximide significantly reduced NOS activity and the occurrence of apoptosis. These findings suggest that NO is involved in the degenerative process of vestibular epithelia caused by aminoglycosides.

Aminoglycosides↗
PubMed1999

Glutamate toxicity induced degeneration of outer hair cells with a temporal increase of nitric oxide production in the guinea pig cochlea.

The aim of this study was to examine the roles of glutamate (GLU) toxicity and involvement of nitric oxide (NO) in the pathogenesis of cochlear degeneration. We examined guinea pig cochleae following chronic exposure to GLU. Trypan blue extrusion and transmission electron microscopy were performed to evaluate degeneration in the organ of Corti. In parallel, nitric oxide synthase (NOS) activity was demonstrated by histochemical staining of NADPH diapholase. GLU treatment caused time-dependent degeneration of outer hair cells (OHCs) in conjunction with a temporal increase of NOS activity in the organ of Corti. This suggests that GLU may be involved in OHC degeneration under toxic conditions, with NO production possibly playing a role in this process.

Animals↗
PubMed1999

Cystine protects cochlear outer hair cells against glutamate toxicity.

We previously reported that long-term exposure to glutamate (Glu) induced death of cochlear outer hair cells (OHCs). However, the mechanisms of OHC death induced by Glu were unclear. In the central nervous system, Glu is known to interfere with a cystine-Glu antiporter, leading to a decrease in cystine uptake and reducing the intracellular glutathione level. We therefore investigated the effect of cystine supplementation on degeneration of OHCs caused by long-term exposure to Glu. Supplementation of cystine significantly decreased the number of dying OHCs. These findings suggest that a cystine-Glu interaction may be involved in the mechanism of OHC degeneration caused by Glu.

Analysis of Variance↗
PubMed1999

Interaction between fibronectin and eosinophils in the growth of nasal polyps.

OBJECTIVES: The aim of this study was to determine roles of fibronectin and eosinophils in the etiology of nasal polyposis. STUDY DESIGN: We designed a cohort study of cases with nasal polyposis. Sampled nasal polyps were differentiated by their histopathologic characteristics, and compared by size and computed tomography (CT) stage. METHODS: The size of nasal polyps was determined on the basis of the endoscopic findings, and the extent of sinusitis was evaluated by CT staging. Nasal polyp samples were taken from 82 patients during ethmoidectomy and differentiated by morphologic characteristics, infiltration cell types, or fibronectin positivity. Then their sizes and CT stages were compared. In addition, correlation among these histological characteristics was analyzed. RESULTS: Nasal polyps showing edematous morphology, eosinophil infiltration, or fibronectin expression were significantly large in size. Concerning CT stages, only the infiltration cell type showed a significant difference. Significant correlation among edematous morphology, eosinophil infiltration, and fibronectin expression was also recognized. CONCLUSIONS: These findings suggest that interaction between eosinophils and fibronectin may play a role in edema formation, which contributes to the growth of nasal polyps.

Adolescent↗
PubMed1999

A prokaryotic gene cluster involved in synthesis of lysine through the amino adipate pathway: a key to the evolution of amino acid biosynthesis.

In previous studies we determined the nucleotide sequence of the gene cluster containing lys20, hacA (lys4A), hacB (lys4B), orfE, orfF, rimK, argC, and argB of Thermus thermophilus, an extremely thermophilic bacterium. In this study, we characterized the role of each gene in the cluster by gene disruption and examined auxotrophy in the disruptants. All disruptants except for the orfE disruption showed a lysine auxotrophic phenotype. This was surprising because this cluster consists of genes coding for unrelated proteins based on their names, which had been tentatively designated by homology analysis. Although the newly found pathway contains alpha-aminoadipic acid as a lysine biosynthetic intermediate, this pathway is not the same as the eukaryotic one. When each of the gene products was phylogenetically analyzed, we found that genes evolutionarily-related to the lysine biosynthetic genes in T. thermophilus were all present in a hyperthermophilic and anaerobic archaeon, Pyrococcus horikoshii, and formed a gene cluster in a manner similar to that in T. thermophilus. Furthermore, this gene cluster was analogous in part to the present leucine and arginine biosyntheses pathways. This lysine biosynthesis cluster is assumed to be one of the origins of lysine biosynthesis and could therefore become a key to the evolution of amino acid biosynthesis.

2-Aminoadipic Acid↗
PubMed1999

Diverse oxygenations catalyzed by carbazole 1,9a-dioxygenase from Pseudomonas sp. Strain CA10.

Carbazole 1,9a-dioxygenase (CARDO) from Pseudomonas sp. strain CA10 is a multicomponent enzyme that catalyzes the angular dioxygenation of carbazole, dibenzofuran, and dibenzo-p-dioxin. It was revealed by gas chromatography-mass spectrometry and 1H and 13C nuclear magnetic resonance analyses that xanthene and phenoxathiin were converted to 2,2',3-trihydroxydiphenylmethane and 2,2',3-trihydroxydiphenyl sulfide, respectively. Thus, for xanthene and phenoxathiin, angular dioxygenation by CARDO occurred at the angular position adjacent to the oxygen atom to yield hetero ring-cleaved compounds. In addition to the angular dioxygenation, CARDO catalyzed the cis dihydroxylation of polycyclic aromatic hydrocarbons and biphenyl. Naphthalene and biphenyl were converted by CARDO to cis-1, 2-dihydroxy-1,2-dihydronaphthalene and cis-2,3-dihydroxy-2, 3-dihydrobiphenyl, respectively. On the other hand, CARDO also catalyzed the monooxygenation of sulfur heteroatoms in dibenzothiophene and of the benzylic methylenic group in fluorene to yield dibenzothiophene-5-oxide and 9-hydroxyfluorene, respectively. These results indicate that CARDO has a broad substrate range and can catalyze diverse oxygenation: angular dioxygenation, cis dihydroxylation, and monooxygenation. The diverse oxygenation catalyzed by CARDO for several aromatic compounds might reflect the differences in the binding of the substrates to the reaction center of CARDO.

Anthracenes↗
PubMed1999

Double high-dose chemotherapy supported by autologous transplantation of peripheral blood stem cells for treatment of an elderly patient with small-cell lung cancer.

We report a 62-year-old male with extensive disease small-cell lung cancer (SCLC) who was successfully treated with double high-dose chemotherapy supported by autologous peripheral blood stem cell transplantation (auto-PBSCT). This patient achieved a partial response with 3 cycles of induction chemotherapy. After the peripheral blood stem cell mobilization, two cycles of high-dose ICE regimen (ifosfamide 3,000 mg/m2 at days 1 to 5, carboplatin 400 mg/m2 at days 1, 3, 5, and etoposide 500 mg/m2 at days 1, 3, 5) could be given with further regression of the tumor and acceptable toxicities. This successful case suggests the feasibility of double high-dose ICE with auto-PBSCT in elderly patients with SCLC.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Aspergillus osteomyelitis in a child who has p67-phox-deficient chronic granulomatous disease.

Here we describe Aspergillus osteomyelitis of the tibia in a 9-year-old boy who has an autosomal recessive form of chronic granulomatous disease (CGD). The patient showed a p67-phagocyte oxidase (phox) deficiency, which is rare type of CGD in Japan. The initial treatment which consisted of surgical debridement and antibiotic therapy with amphotericin B (AMPH), did not control the infection. Aspergillus fumigatus (A. fumigatus) pure isolated from drainage fluid and necrotic bone tissue demonstrated less susceptible to antifungal agents, including AMPH, fluconazole and flucytosine. Recombinant interferon gamma was then administrated, and it was effective in controlling the course of severe invasive aspergillosis. This report indicates the use of interferon gamma might be helpful in control for Aspergillus osteomyelitis of the tibia in a child with CGD demonstrated p67-phox deficiency refractory to conventional therapy with AMPH.

Amphotericin B↗
PubMed1999

Loss of HLA haplotype in lung cancer cell lines: implications for immunosurveillance of altered HLA class I/II phenotypes in lung cancer.

Loss of expression of HLA class I antigens has been demonstrated in a wide variety of tumors and is considered to be one of the mechanisms whereby tumors escape T-cell surveillance. Genomic DNA of MHC class I/II molecules in seven lung cancer cell lines was investigated and compared with that in peripheral blood mononuclear cells. In three cell lines, OU-LC-A1, OU-LC-A2, and OU-LC-AS1, a loss of HLA haplotype was observed. Aberrations of HLA class I/II in tumor cell lines should be considered when MHC-restricted phenomena in vitro models are assessed and clinical use of tumor vaccination in vivo is considered.

Carcinoma, Non-Small-Cell Lung↗
PubMed1998

Minimum light intensity required to suppress nocturnal melatonin concentration in human saliva.

We set out to determine the minimum intensity of light able to suppress nocturnal melatonin levels as measured in normal human saliva. Five healthy male volunteers were exposed to light at different intensities (<10, 500, 1000, 2500, and 5000 lux) in a repeated measure design. Suppression of melatonin was dependent on both light intensity and duration of light exposure. Minimum intensities of light suppressing nocturnal melatonin levels were calculated as 393, 366, 339, and 285 lux for exposure durations of 30, 60, 90, and 120 min, respectively. Minimum effective intensity and duration of light exposure showed a linear inverse relationship. These results suggest that less intensity of light than previously reported suffices to suppress melatonin in humans, and that caution is required in interpreting studies using long exposure to dim light as a background condition.

Adult↗