35 results on '"Kenji Muraoka"'
Search Results
2. Identification of active and taxonomically diverse 1,4-dioxane degraders in a full-scale activated sludge system by high-sensitivity stable isotope probing
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Tomoyuki Hori, Daisuke Mayumi, Kenji Muraoka, Fumiaki Morishita, Yutaka Sugiyama, Hiroshi Habe, Yoshitomo Kikuchi, Atsushi Ogata, Daisuke Ichikawa, and Tomo Aoyagi
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0301 basic medicine ,Microorganism ,030106 microbiology ,Microbial Consortia ,Microbial metabolism ,Stable-isotope probing ,010501 environmental sciences ,Wastewater ,01 natural sciences ,Microbiology ,Article ,Dioxanes ,03 medical and health sciences ,Isotopes ,RNA, Ribosomal, 16S ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,Pollutant ,biology ,Bacteria ,Sewage ,Ribosomal RNA ,biology.organism_classification ,RNA, Bacterial ,Activated sludge ,Microbial population biology ,Environmental chemistry - Abstract
1,4-Dioxane is one of the most common and persistent artificial pollutants in petrochemical industrial wastewaters and chlorinated solvent groundwater plumes. Despite its possible biological treatment in natural environments, the identity and dynamics of the microorganisms involved are largely unknown. Here, we identified active and diverse 1,4-dioxane-degrading microorganisms from activated sludge by high-sensitivity stable isotope probing of rRNA. By rigorously analyzing 16S rRNA molecules in RNA density fractions of 13C-labeled and unlabeled 1,4-dioxane treatments, we discovered 10 significantly 13C-incorporating microbial species from the complex microbial community. 16S rRNA expression assays revealed that 9 of the 10 species, including the well-known degrader Pseudonocardia dioxanivorans, an ammonia-oxidizing bacterium and phylogenetically novel bacteria, increased their metabolic activities shortly after exposure to 1,4-dioxane. Moreover, high-resolution monitoring showed that, during a single year of operation of the full-scale activated sludge system, the nine identified species exhibited yearly averaged relative abundances of 0.001–1.523%, and yet showed different responses to changes in the 1,4-dioxane removal efficiency. Hence, the co-existence and individually distinct dynamics of various 1,4-dioxane-degrading microorganisms, including hitherto unidentified species, played pivotal roles in the maintenance of the biological system removing the recalcitrant pollutant.
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- 2018
3. Self-Holding Magneto-Optical Switch Integrated With Thin-Film Magnet
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Ken Okazeri, Shigehisa Arai, Nobuhiko Nishiyama, Yuya Shoji, Kenji Muraoka, Shigeki Nakagawa, and Tetsuya Mizumoto
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010302 applied physics ,Materials science ,business.industry ,01 natural sciences ,Waveguide (optics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Power (physics) ,Magneto optical ,010309 optics ,Electrical current ,Extinction (optical mineralogy) ,Magnet ,0103 physical sciences ,Optoelectronics ,Electrical and Electronic Engineering ,Current (fluid) ,Thin film ,business - Abstract
We demonstrate a novel self-holding function of a magneto-optical waveguide switch. The switching state is flipped by a pulsed current and maintained without any power supply by virtue of the nonvolatility of the thin-film magnet. Extinction ratios up to 15.4 dB were demonstrated. The switch state was controlled by a 1- $\mu \text{s}$ pulsed electrical current.
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- 2018
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4. Self-Holding Operation of Magneto-Optical Switch using Thin-Film Magnet
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Kenji Muraoka, Tetsuya Mizumoto, Yuya Shoji, Shigeki Nakagawa, Nobuhiko Nishiyama, Shigehisa Arai, and Ken Okazeri
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010302 applied physics ,Materials science ,business.industry ,Physics::Optics ,01 natural sciences ,Waveguide (optics) ,Power (physics) ,010309 optics ,Magnet ,Wavelength-division multiplexing ,0103 physical sciences ,Optoelectronics ,Current (fluid) ,Thin film ,business ,Electron-beam lithography ,Free-space optical communication - Abstract
A novel self-holding switch is demonstrated by a magneto-optical waveguide switch. The switching state is flipped by a pulsed current and maintained without any power supply by virtue of the non-volatility of thin-film magnet.
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- 2018
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5. Determining the Closed Flux Surface in a Helical Plasma in TOKASTAR-2 with an Electrostatic Probe
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Takaaki Fujita, Ryoma Yokoyama, Ryoichi Sugioka, Atsushi Okamoto, Kenji Muraoka, Takahiro Yamauchi, Hideki Arimoto, Hiromasa Itou, Masato Minoura, and Kohei Yasuda
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Surface (mathematics) ,Materials science ,Flux ,Plasma ,Condensed Matter Physics ,Molecular physics - Published
- 2018
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6. Synthesis of Conjugated Oligomers Having Aromatic and Enediyne Units Alternately in the Backbone that Show Intense Fluorescence Emission
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Yuuki Takayama, Hiroyuki Ohtani, Yuuki Nakano, Kenji Muraoka, Fumie Sato, and Kenichi Ishizuka
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Organic Chemistry ,Conjugated system ,Ring (chemistry) ,Photochemistry ,Biochemistry ,Fluorescence ,chemistry.chemical_compound ,chemistry ,Pyridine ,Intense fluorescence ,Thiophene ,Enediyne ,Physical and Theoretical Chemistry ,Benzene - Abstract
[structure: see text] Synthesis and fluorescence properties of pi-conjugated compounds having alternately an aromatic ring such as benzene, pyridine, and thiophene and an enediyne unit in the backbone are described.
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- 2004
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7. My Historical Studies of the 19th-Century BritainーA Personal Historyー
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Kenji, Muraoka
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- 2003
8. Engraftment and dissemination of T lymphocytes from primary haemophagocytic lymphohistiocytosis inscidmice
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Fumio Yanai, Eiichi Ishii, Yuhei Hamasaki, Shinsaku Imashuku, Masaki Yasukawa, Koichi Oshima, Miyoko Imayoshi, Masahiro Sako, Yong Dong Park, Atushi Ogawa, Kenji Muraoka, Nobuyuki Yoshida, Satoshi Kataoka, Kayoko Koide, and Masafumi Zaitsu
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Hemophagocytic lymphohistiocytosis ,Pathology ,medicine.medical_specialty ,biology ,CD68 ,Perforin Deficiency ,CD3 ,Hematology ,T lymphocyte ,medicine.disease ,Perforin ,Immunology ,biology.protein ,medicine ,Infiltration (medical) ,CD8 - Abstract
Summary. Although primary haemophagocytic lymphohistiocytosis (HLH) is a genetic disorder of T lymphocytes, it remains unclear why T lymphocytes of primary HLH patients preferentially infiltrate the central nervous system and peripheral blood, in addition to the reticuloendothelial systems. We engrafted Herpesvirus saimiri (HVS)-immortalized T-lymphocyte lines established from primary HLH patients into severe combined immunodeficient (scid) mice and examined their capacity to infiltrate mouse organs. A diffuse infiltration of human T lymphocytes was detected in each organ of scid mice treated with 1 × 106 T lymphocytes from all four primary HLH patients assessed, whereas no infiltration of T lymphocytes from healthy individuals was observed in any organ. The infiltration of T lymphocytes was mainly observed in the lung, brain and peripheral blood, in association with haemophagocytosis. These cells were positive for HLA-DR, CD3 and either CD8 or CD4, but negative for CD68. Certain markers of proliferation and apoptotic activities were highly positive in these cells. There was no difference between the infiltration pattern of T lymphocytes of primary HLH patients with a perforin deficiency and those without. By Southern blot analysis, T lymphocytes infiltrating mouse organs were observed to be polyclonal. These findings suggest that our murine model implementing HVS-immortalized human T lymphocytes is suitable to clarify the pathogenesis of primary HLH.
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- 2003
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9. Efficient and General Synthetic Method for Preparing Oligoenynes with Either trans- or cis-Olefinic Configuration
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Kenji Muraoka, Fumie Sato, Christophe Delas, and Yuuki Takayama
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Chemistry ,Organic Chemistry ,Physical and Theoretical Chemistry ,Variety (universal algebra) ,Biochemistry ,Combinatorial chemistry - Abstract
[reaction: see text] Efficient and practical synthesis of a variety of 1-iodo-4-trimethylsilylbut-1-en-3-yne derivatives with trans- and cis-olefinic configuration, and their repeated use as building blocks for the synthesis of trans- and cis-oligoenynes, respectively, are described.
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- 2003
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10. Identification of simultaneous mutation of fibrinogen α chain and protein C genes in a Japanese kindred
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Sachiko Kinoshita, Atsushi Shibuya, Eiichi Ishii, Kumiko Watanabe, Sumiko Inoue, Hiroko Iida, Naotaka Hamasaki, Kenji Muraoka, Machiko Wakiyama, Masafumi Zaitsu, Masako Kurihara, Yui Wada, and Miyuki Ono
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Mutation ,Hematology ,Biology ,Fibrinogen ,medicine.disease_cause ,medicine.disease ,Molecular biology ,Exon ,Protein C deficiency ,medicine ,Gene ,Protein C ,Fibrinogen alpha chain ,medicine.drug ,Blood coagulation test - Abstract
Afibrinogenaemia usually induces a bleeding tendency during infancy, whereas protein C deficiency increases susceptibility to thrombosis in children or adolescence. Mutations of these genes have been, therefore, established as independent risk factors for coagulation disorders. We describe the homozygous mutation of the fibrinogen alpha chain gene and additional heterozygous mutation of the protein C gene in a male infant who showed prolonged umbilical bleeding after birth. On examination, the plasma fibrinogen was undetectable, and the activity and antigen level of protein C were reduced. The patient showed no fibrinogen Aalpha chain as well as Bbeta and gamma chains by Western blotting. The sequencing analysis showed the homozygous deletion of 1238 bases from intron 3 at position 2008 to intron 4 at position 3245 in the fibrinogen alpha chain gene. Both parents were heterozygous carriers of this mutation. In this patient, an additional mutation was also detected in the protein C gene: the heterozygous deletion of exon 7 at position 6161-6163 or 6164-6166, resulting the deletion of one amino acid (Lys150 or 151). His mother was also a carrier of this mutation. As the simultaneous mutation of the fibrinogen alpha chain and protein C genes has not been previously reported, the influence of the interaction between these two mutations on the clinical manifestations of this patient should be carefully monitored for a long period.
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- 2002
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11. Soluble Interleukin-6 (IL-6) Receptor With IL-6 Stimulates Megakaryopoiesis From Human CD34+ Cells Through Glycoprotein (gp)130 Signaling
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Ryuhei Tanaka, Kiyoshi Yasukawa, Makoto Yoshida, Tatsutoshi Nakahata, Kaoru Yamada, Kohichiro Tsuji, Tadamitsu Kishimoto, Xingwei Sui, Tetsuya Taga, Kenji Muraoka, and Yasuhiro Ebihara
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medicine.medical_specialty ,Cellular differentiation ,medicine.medical_treatment ,Immunology ,Stem cell factor ,Cell Biology ,Hematology ,Biology ,Biochemistry ,Molecular biology ,Endocrinology ,Cytokine ,Cell culture ,Internal medicine ,Interleukin-6 receptor ,medicine ,Stem cell ,Progenitor cell ,Megakaryopoiesis - Abstract
We have recently shown that stimulation of glycoprotein (gp) 130, the membrane-anchored signal transducing receptor component of IL-6, by a complex of human soluble interleukin-6 receptor (sIL-6R) and IL-6 (sIL-6R/IL-6), potently stimulates the ex vivo expansion as well as erythropoiesis of human stem/progenitor cells in the presence of stem cell factor (SCF). Here we show that sIL-6R dose-dependently enhanced the generation of megakaryocytes (Mks) (IIbIIIa-positive cells) from human CD34+ cells in serum-free suspension culture supplemented with IL-6 and SCF. The sIL-6R/IL-6 complex also synergistically acted with IL-3 and thrombopoietin (TPO) on the generation of Mks from CD34+ cells, whereas the synergy of IL-6 alone with TPO was barely detectable. Accordingly, the addition of sIL-6R to the combination of SCF + IL-6 also supported a substantial number of Mk colonies from CD34+ cells in serum-free methylcellulose culture, whereas SCF + IL-6 in the absence of sIL-6R rarely induced Mk colonies. The addition of monoclonal antibodies against gp130 to the suspension and clonal cultures completely abrogated the megakaryopoiesis induced by sIL-6R/IL-6 in the presence of SCF, whereas an anti-TPO antibody did not, indicating that the observed megakaryopoiesis by sIL-6R/IL-6 is a response to gp130 signaling and independent of TPO. Furthermore, human CD34+ cells were subfractionated into two populations of IL-6R–negative (CD34+ IL-6R−) and IL-6R–positive (CD34+ IL-6R+) cells by fluorescence-activated cell sorting. The CD34+IL-6R− cells produced a number of Mks as well as Mk colonies in cultures supplemented with sIL-6R/IL-6 or TPO in the presence of SCF. In contrast, CD34+ IL-6R+cells generated much less Mks and lacked Mk colony forming activity under the same conditions. Collectively, the present results indicate that most of the human Mk progenitors do not express IL-6R, and that sIL-6R confers the responsiveness of human Mk progenitors to IL-6. Together with the presence of functional sIL-6R in human serum and relative unresponsiveness of human Mk progenitors to IL-6 in vitro, current results suggest that the role of IL-6 may be mainly mediated by sIL-6R, and that the gp130 signaling initiated by the sIL-6R/ IL-6 complex is involved in human megakaryopoiesis in vivo.
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- 1999
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12. Interferon-γ and Human Megakaryopoiesis
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Tatsutoshi Nakahata, Kenji Muraoka, and Kohichiro Tsuji
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Cancer Research ,CD34 ,Drug Synergism ,Stem cell factor ,Hematology ,Biology ,Hematopoietic Stem Cells ,Hematologic Diseases ,Hematopoiesis ,Interferon-gamma ,Haematopoiesis ,Immune system ,Oncology ,Immunology ,Cancer research ,medicine ,Cytokines ,Humans ,Interferon gamma ,Progenitor cell ,Megakaryocytes ,Cellular Senescence ,Thrombopoietin ,Megakaryopoiesis ,medicine.drug - Abstract
Interferon-gamma (IFN-gamma) exhibits various properties including antigrowth activity in neoplastic and normal cells and regulatory roles in immune responses and hematopoiesis, but studies of IFN-gamma effects on human megakaryopoiesis have been inconclusive. Recently we have used serum-free culture of purified CD34+ cells to demonstrate that IFN-gamma stimulates the proliferation of relatively mature megakaryocytic progenitors independently of thrombopoietin. It has been also shown that IFN-gamma stimulates the maturation of megakaryocytes, and has a significant synergism with stem cell factor in human megakaryopoiesis. Further studies are needed to clarify the in vivo effect of IFN-gamma on human megakaryopoiesis and the clinical relevance of IFN-gamma.
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- 1998
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13. Synergistic Action of Flt3 and gp130 Signalings in Human Hematopoiesis
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Stewart D. Lyman, Kenji Muraoka, Tatsutoshi Nakahata, Xingwei Sui, Ryuhei Tanaka, Makoto Yoshida, Kaoru Yamada, Kohichiro Tsuji, and Yasuhiro Ebihara
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medicine.medical_specialty ,Immunology ,CD34 ,Antigens, CD34 ,Receptors, Cell Surface ,Stem cell factor ,Biology ,Biochemistry ,Antigens, CD ,Proto-Oncogene Proteins ,Internal medicine ,hemic and lymphatic diseases ,Cytokine Receptor gp130 ,medicine ,Humans ,Progenitor cell ,Cells, Cultured ,Stem Cell Factor ,Membrane Glycoproteins ,Interleukin-6 ,Antibodies, Monoclonal ,Receptor Protein-Tyrosine Kinases ,Drug Synergism ,Cell Biology ,Hematology ,Fetal Blood ,Receptors, Interleukin-6 ,Molecular biology ,Hematopoiesis ,Haematopoiesis ,Endocrinology ,fms-Like Tyrosine Kinase 3 ,Cell culture ,Fms-Like Tyrosine Kinase 3 ,Erythropoiesis ,Myelopoiesis ,Signal Transduction - Abstract
We recently showed that c-kit signal synergizes with glycoprotein (gp)130 signal mediated by a complex of interleukin (IL)-6 and soluble IL-6 receptor (IL-6/sIL-6R) to stimulate the expansion of human primitive hematopoietic progenitor cells and erythropoietin-independent erythropoiesis. In the present study, we examined the effect of a ligand for Flt3 (FL), whose receptor tyrosine kinase is closely related to c-kit, in combination with IL-6/sIL-6R on human hematopoiesis in vitro. In serum-containing methylcellulose clonal culture of cord blood CD34+ cells, whereas FL alone stimulated only granulocyte-macrophage (GM) colony formation, erythroid bursts and mixed colonies in addition to GM colonies were induced by FL with IL-6/sIL-6R, but not IL-6/sIL-6R alone. In suspension culture, CD34+ cells generated a small number of myeloid cells in the presence of FL or IL-6/sIL-6R alone. However, the addition of IL-6/sIL-6R to the culture with FL induced the generation of a significant number of erythroid cells and megakaryocytes in addition to myeloid cells. The combination of FL and IL-6/sIL-6R also induced a remarkable expansion of GM colony- and erythroid burst-forming cells and multipotential progenitors, although FL or IL-6/sIL-6R alone induced the generation of only a small number of progenitors for GM colonies. The synergistic effects of FL and IL-6/sIL-6R were confirmed in serum-free clonal and suspension cultures. In addition, the addition of anti-human gp130 monoclonal antibodies abrogated the synergistic action. These results indicate that Flt3 signal, as well as c-kit signal, synergizes with gp130 signal to stimulate human myelopoiesis, erythropoiesis and megakaryopoiesis, and the expansion of primitive multipotential hematopoietic progenitor cells.
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- 1997
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14. Thrombopoietin alone stimulates the early proliferation and survival of human erythroid, myeloid and multipotential progenitors in serum‐free culture
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Hiroshi Miyazaki, Ryuhei Tanaka, Tatsutoshi Nakahata, Kenji Muraoka, Yasuhiro Ebihara, Makoto Yoshida, and Kohichiro Tsuji
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endocrine system ,Cell Survival ,Antigens, CD34 ,Stem cell factor ,Biology ,Culture Media, Serum-Free ,Precursor cell ,Humans ,Progenitor cell ,Cells, Cultured ,Thrombopoietin ,Blood Cells ,Recombinant Human Thrombopoietin ,food and beverages ,hemic and immune systems ,Hematology ,Fetal Blood ,Hematopoietic Stem Cells ,Molecular biology ,Haematopoiesis ,Cell culture ,embryonic structures ,Immunology ,Cytokines ,Stem cell ,Megakaryocytes ,Cell Division - Abstract
We examined the effects of recombinant human thrombopoietin (TPO, c-Mpl ligand) on the proliferation and differentiation of human haemopoietic progenitors other than megakaryocytic progenitors using serum-free cultures. TPO alone supported the generation of not only megakaryocytic (MK) but also blast cell (blast) colonies from cord blood CD34+ cells. Delayed addition of a cytokine cocktail (cytokines; interleukin (IL)-3, IL-6, stem cell factor, erythropoietin, granulocyte-macrophage colony-stimulating factor, and TPO) to cultures with TPO alone on day 7 induced various colonies including granulocyte-macrophage (GM) colonies, erythroid bursts (E), granulocyte-erythrocyte-macrophage-megakaryocyte (GEMM) colonies. Replating experiments of blast colonies supported by TPO alone for culture with cytokines revealed that approximately 60% of the blast colonies contained various haemopoietic progenitors. Single cell cultures of clone-sorted CD34+ cells indicated that TPO supported the early proliferation and/or survival of both primitive and committed haemopoietic progenitors. In serum-free suspension cultures, TPO alone significantly stimulated the production of progenitors for MK, GM, E and GEMM colonies as well as long-term culture-initiating cells. These effects were completely abrogated by anti-TPO antibody. These results suggest that TPO is an important cytokine in the early proliferation of human primitive as well as committed haemopoietic progenitors, and in the ex vivo manipulation of human haemopoietic progenitors.
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- 1997
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15. Outbreak of acute glomerulonephritis in children: Observed association with the T1 subtype of group A streptococcal infection in Northern Kyushu, Japan
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Kohji Shimazaki, Kenji Muraoka, Mikiko Ide, Tatsuo Masuyama, Toshiro Hara, Tatsuhiko Koga, Hideto Yamaguchi, Kazuo Moriya, Eiichi Ishii, Satoshi Honjo, and Sumio Miyazaki
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Adult ,Male ,Serotype ,Adolescent ,Streptococcus pyogenes ,medicine.disease_cause ,Group A ,Disease Outbreaks ,Serology ,Glomerulonephritis ,Japan ,Streptococcal Infections ,Group A streptococcal infection ,Humans ,Medicine ,Serotyping ,Child ,Aged ,business.industry ,Incidence (epidemiology) ,Infant ,Outbreak ,Middle Aged ,medicine.disease ,Child, Preschool ,Acute Disease ,Pediatrics, Perinatology and Child Health ,Immunology ,Rheumatic fever ,Female ,Rheumatic Fever ,business - Abstract
Group A streptococcal infection is associated with the occurrence of acute glomerulonephritis (AGN) and rheumatic fever (RF). A surveillance study in the Saga area, in northern Kyushu, Japan, showed a small variation in the reported number of group A streptococcal infections in the period 1988-94. However, of the AGN cases reported in this period, more than half were observed in 1992. In order to examine whether some change had occurred in the serotype distribution of Streptococcus pyogenes during the period, patients in the Saga area diagnosed as having group A streptococcal infection and patients with AGN or RF were analyzed. Serological T-typing of S. pyogenes was carried out for patients with group A streptococcal infections, and the association between the occurrence of AGN or RF and the distribution of each different T subtype was analyzed. M-typing of S. pyogenes was also carried out and the correlation between T and M types was examined. From 1988 to 1994, the annual number of patients with group A streptococcal infections in the Saga area showed a small variation, range 65-100 patients/year. Of the 42 patients with AGN and three with RF observed in this period, 27 with AGN (64%) and one with RF (33.3%) were detected in 1992. Only the T1 subtype increased in 1992; the other T subtypes showed little variation in incidence. The number of patients with the T1 subtype was significantly correlated with the occurrence of AGN by regression analysis (P < 0.01). Of the 170 subjects tested for both T and M subtypes, 44 of the 45 T1-typed subjects had the M1 protein. Our epidemiological study suggested that the T1 subtype of streptococcal infection was associated with an outbreak of AGN in 1992 in the Saga area.
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- 1996
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16. Erythropoietin-independent erythrocyte production: signals through gp130 and c-kit dramatically promote erythropoiesis from human CD34+ cells
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Xingwei Sui, Tatsutoshi Nakahata, Kenji Muraoka, S Tajima, Kiyoshi Yasukawa, Kohichiro Tsuji, Ryuhei Tanaka, Tetsuya Taga, Yasuhiro Ebihara, Kenji Ikebuchi, and Tadamitsu Kishimoto
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Erythrocytes ,medicine.drug_class ,Cellular differentiation ,Immunology ,CD34 ,Antigens, CD34 ,Stem cell factor ,Biology ,Monoclonal antibody ,Antigens, CD ,hemic and lymphatic diseases ,Cytokine Receptor gp130 ,medicine ,Humans ,Immunology and Allergy ,Erythropoiesis ,Erythropoietin ,Stem Cell Factor ,Membrane Glycoproteins ,Interleukin-6 ,Cell Differentiation ,Articles ,Receptors, Interleukin ,Hematopoietic Stem Cells ,Receptors, Interleukin-6 ,Molecular biology ,Recombinant Proteins ,Clone Cells ,Kinetics ,Proto-Oncogene Proteins c-kit ,Haematopoiesis ,Stem cell ,Cell Division ,Signal Transduction ,medicine.drug - Abstract
Erythropoietin (EPO) is the primary humoral regulator of erythropoiesis and no other factor has previously been reported to support proliferation and terminal maturation of erythroid cells from hemopoietic stem cells. Here we show that stimulation of glycoprotein (gp130) by a combination of recombinant human soluble interleukin 6 receptor (sIL-6R) and IL-6 but not sIL-6R or IL-6 alone can support proliferation, differentiation, and terminal maturation of erythroid cells in the absence of EPO from purified human CD34+ cells in suspension culture containing stem cell factor (SCF). A number of erythroid bursts and mixed erythroid colonies also developed in methylcellulose culture under the same combination. The addition of anti-gp130 monoclonal antibodies but not anti-EPO antibody to the same culture completely abrogated the generation of erythroid cells. These results clearly demonstrate that mature erythroid cells can be emerged from hemopoietic progenitors without EPO in vitro. Together with the previous reports that human sera contain detectable levels of sIL-6R, IL-6, and SCF, current data suggest that gp130 signaling in association with c-kit activation may play a role in human erythropoiesis in vivo.
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- 1996
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17. gp130 and c-Kit signalings synergize for ex vivo expansion of human primitive hemopoietic progenitor cells
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Kenji Ikebuchi, Yasuhiro Ebihara, Tadamitsu Kishimoto, Xingwei Sui, Kenji Muraoka, Kohichiro Tsuji, Tetsuya Taga, S Tajima, Kiyoshi Yasukawa, and Ryuhei Tanaka
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Macromolecular Substances ,CD34 ,Antigens, CD34 ,Stem cell factor ,Biology ,Colony-Stimulating Factors ,Antigens, CD ,Proto-Oncogene Proteins ,Precursor cell ,Granulocyte Colony-Stimulating Factor ,Receptors, Colony-Stimulating Factor ,medicine ,Humans ,Progenitor cell ,Erythropoietin ,Cells, Cultured ,Interleukin 3 ,Multidisciplinary ,Dose-Response Relationship, Drug ,Interleukin-6 ,Infant, Newborn ,Antibodies, Monoclonal ,Granulocyte-Macrophage Colony-Stimulating Factor ,Receptor Protein-Tyrosine Kinases ,Receptors, Interleukin ,Fetal Blood ,Hematopoietic Stem Cells ,Colony-stimulating factor ,Receptors, Interleukin-6 ,Molecular biology ,Recombinant Proteins ,Clone Cells ,Proto-Oncogene Proteins c-kit ,Haematopoiesis ,Granulocyte macrophage colony-stimulating factor ,Cytokines ,Interleukin-3 ,Cell Division ,Research Article ,medicine.drug - Abstract
gp130, a signal-transducing receptor component of interleukin 6 (IL-6), associates with an IL-6 and IL-6 receptor (IL-6) complex and transduces signals. To examine the role of gp130 signaling in the expansion of human hemopoietic progenitor cells, we tested the effects of a recombinant soluble human IL-6 receptor (sIL-6R) and/or IL-6 in combination with other cytokines on purified human umbilical cord blood CD34+ cells, using methylcellulose clonal assay and suspension culture in the presence or absence of serum. A combination of sIL-6R and IL-6 (sIL-6R/IL-6), but not sIL-6R or IL-6 alone, was found to dramatically stimulate expansion of hemopoietic progenitor cells as well as CD34+ cells in the presence of stem cell factor. Significant generation of multipotential hemopoietic progenitors over a period of 3 weeks in suspension culture and efficient formation of colonies, especially multilineage and blast cell colonies, in methylcellulose assay supplemented with a combination of sIL-6R/IL-6 together with stem cell factor were observed in serum-containing and serum-free culture. Addition of anti-gp130 monoclonal antibodies or anti-IL-6R monoclonal antibodies to the above cultures dose-dependently inhibited the expansion of progenitor cells in suspension culture and also completely blocked the formation of multilineage colonies in methylcellulose culture. These findings demonstrated that the significant expansion of human primitive hemopoietic progenitors could be achieved with the gp130 and c-Kit signalings initiated by the sIL-6R/IL-6 complex in the presence of stem cell factor and suggested the possible application of this method for ex vivo expansion of CD34+ cells for bone marrow transplantation.
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- 1995
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18. Nucleation and Growth Phenomena in Producing Monodispersed Lead Sulfate Particles by Reactive Crystallization
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Kenji Muraoka, Daisuke Katou, Izumi Hirasawa, and Ken Toyokura
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Lead sulfate ,Chemistry ,law ,General Chemical Engineering ,Inorganic chemistry ,Nucleation ,Crystal growth ,General Chemistry ,Crystallization ,law.invention - Abstract
本研究では, 回分攪拌槽を用いて, 鉛イオン10-2mol/l, ゼラチン5wt%, 酢酸3.48mol/lを含む水溶液に, 硝酸鉛及び硫酸ナトリウム水溶液 (濃度0.025~0.4mol/l) をそれぞれ別の供給管より攪拌翼近傍に, 連続的に供給し, 攪拌回転数400rpmで混合することにより, 鉛イオン過剰で等モル反応させて硫酸鉛結晶を生成した。この生成過程において, 装置内の結晶を経時的に採取し, 個数基準の粒径分布を実測するとともに, 結晶の形状, 表面状態の変化を観察した.この結果, 原料モル濃度0.4~0.5mol/lを境に核発生が認められる場所が変化することを示し, この現象を装置内過飽和度比と関連づけて考察した.さらに本実験条件下で比較的単分散の均一微粒子が得られる範囲において, 反応初期は不安定な状態の結晶が生成するが, その後安定な菱形になることが観察された.安定な状態の結晶の成長過程は, 供給原料がすべて装置内結晶の成長により消費されるように成長することを示し, また製品となる核の生成速度が原料過飽和度比の5乗に比例する実験式を提出した.
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- 1995
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19. Measurement of Tokamak Plasma with the External Helical Field Using a High-Speed Camera in TOKASTAR-2
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Yusuke Shimooka, Atsushi Okamoto, Ryoichi Sugioka, Hideki Arimoto, Tatsuya Sakito, Hiromasa Itou, Ryoma Yokoyama, Kouhei Yasuda, Kenji Muraoka, and Takaaki Fujita
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Physics ,Tokamak ,Field (physics) ,High-speed camera ,business.industry ,Magnetic confinement fusion ,Plasma ,Condensed Matter Physics ,01 natural sciences ,Electromagnetic radiation ,010305 fluids & plasmas ,law.invention ,Magnetic field ,Optics ,law ,0103 physical sciences ,Plasma diagnostics ,010306 general physics ,business - Published
- 2016
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20. Development of Magnetic Flux Surface Measurement Method on TOKASTAR-2
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Kenji Muraoka, Yusuke Shimooka, Takaaki Fujita, Atsushi Okamoto, Hideki Arimoto, Ryoma Yokoyama, Tatsuya Sakito, Hiromasa Itou, Ryoichi Sugioka, and Kouhei Yasuda
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Tokamak ,Materials science ,law ,Surface measurement ,Development (differential geometry) ,Condensed Matter Physics ,Magnetic flux ,Stellarator ,law.invention ,Computational physics ,Electron gun - Published
- 2016
- Full Text
- View/download PDF
21. Site-Selective Monotitanation of Dialkynylpyridines and Its Application for Preparation of Highly Fluorescent ?-Conjugated Oligomers
- Author
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Kenji Muraoka, Fumie Sato, Takeshi Hanazawa, Tomohiro Andou, Yuuki Takayama, Mizuki Takahashi, and Hiroyuki Ohtani
- Subjects
chemistry.chemical_compound ,Trimethylsilyl ,chemistry ,Enyne ,Reagent ,Pyridine ,Polymer chemistry ,Site selective ,General Medicine ,Conjugated system ,Fluorescence - Abstract
Reaction of Ti(O-i-Pr)4/2i-PrMgCl reagent with 2,n-bis[(trimethylsilyl)ethynyl]pyridines, where n is 3, 4, 5, and 6, or with 3,4-bis[(trimethylsilyl)ethynyl]pyridines, proceeded with excellent site-selectivity to afford the corresponding monotitanated complex. Synthetic application of the reaction was demonstrated by an efficient preparation of π-conjugated oligomers having pyridine and enyne units alternately, which possess intense blue fluorescence emission.
- Published
- 2005
- Full Text
- View/download PDF
22. Site-selective monotitanation of dialkynylpyridines and its application for preparation of highly fluorescent pi-conjugated oligomers
- Author
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Fumie Sato, Kenji Muraoka, Takeshi Hanazawa, Yuuki Takayama, Tomohiro Andou, Mizuki Takahashi, and Hiroyuki Ohtani
- Subjects
Trimethylsilyl ,Enyne ,Chemistry ,Organic Chemistry ,Conjugated system ,Photochemistry ,Biochemistry ,Fluorescence ,chemistry.chemical_compound ,Reagent ,Polymer chemistry ,Pyridine ,Site selective ,Physical and Theoretical Chemistry - Abstract
Reaction of Ti(O-i-Pr)(4)/2i-PrMgCl reagent with 2,n-bis[(trimethylsilyl)ethynyl]pyridines, where n is 3, 4, 5, and 6, or with 3,4-bis[(trimethylsilyl)ethynyl]pyridines, proceeded with excellent site-selectivity to afford the corresponding monotitanated complex. Synthetic application of the reaction was demonstrated by an efficient preparation of pi-conjugated oligomers having pyridine and enyne units alternately, which possess intense blue fluorescence emission.
- Published
- 2004
23. Highly practical and general synthesis of monodisperse linear pi-conjugated oligoenynes and oligoenediynes with either trans- or cis-olefin configuration
- Author
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Christophe Delas, Yuuki Takayama, Minoru Uemura, Kenji Muraoka, and Fumie Sato
- Subjects
Olefin fiber ,Trimethylsilyl ,Linear polymer ,Dispersity ,Absolute configuration ,General Chemistry ,Conjugated system ,Biochemistry ,Combinatorial chemistry ,Catalysis ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Polymer chemistry ,Molar mass distribution - Abstract
Efficient and practical synthesis of a variety of 1-iodo-4-(trimethylsilyl)but-1-en-3-yne derivatives 1 and 2 with trans- and cis-olefin configuration was described. Their repeated use as building blocks allowed the facile synthesis of trans- and cis-oligoenynes, respectively. Development of a highly practical method for preparing monodisperse trans- and cis-oligoenediynes having the effective conjugation length was also accomplished by using 5 and 4, which can be readily prepared from 1 and 2, respectively.
- Published
- 2003
24. Measurement of Plasma Behavior with High Speed Cameras in TOKASTAR-2
- Author
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Hiromasa Itou, Yuusuke Shimooka, Tatsuya Sakito, Tomohiro Ueda, Takaaki Fujita, Kenji Muraoka, and Hideki Arimoto
- Subjects
Thesaurus (information retrieval) ,Tokamak ,Materials science ,High-speed camera ,law ,Computer graphics (images) ,Plasma ,Condensed Matter Physics ,Stellarator ,law.invention - Published
- 2015
- Full Text
- View/download PDF
25. Identification of simultaneous mutation of fibrinogen alpha chain and protein C genes in a Japanese kindred
- Author
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Kumiko, Watanabe, Atsushi, Shibuya, Eiichi, Ishii, Masako, Kurihara, Sumiko, Inoue, Miyuki, Ono, Yui, Wada, Machiko, Wakiyama, Masafumi, Zaitsu, Hiroko, Iida, Kenji, Muraoka, Sachiko, Kinoshita, and Naotaka, Hamasaki
- Subjects
Male ,Heterozygote ,Blotting, Western ,DNA Mutational Analysis ,Homozygote ,Infant, Newborn ,Fibrinogen ,Protein C Deficiency ,Blood Coagulation Disorders ,Afibrinogenemia ,Polymerase Chain Reaction ,Blotting, Southern ,Japan ,Case-Control Studies ,Humans ,Blood Coagulation Tests ,Gene Deletion ,DNA Primers ,Protein C - Abstract
Afibrinogenaemia usually induces a bleeding tendency during infancy, whereas protein C deficiency increases susceptibility to thrombosis in children or adolescence. Mutations of these genes have been, therefore, established as independent risk factors for coagulation disorders. We describe the homozygous mutation of the fibrinogen alpha chain gene and additional heterozygous mutation of the protein C gene in a male infant who showed prolonged umbilical bleeding after birth. On examination, the plasma fibrinogen was undetectable, and the activity and antigen level of protein C were reduced. The patient showed no fibrinogen Aalpha chain as well as Bbeta and gamma chains by Western blotting. The sequencing analysis showed the homozygous deletion of 1238 bases from intron 3 at position 2008 to intron 4 at position 3245 in the fibrinogen alpha chain gene. Both parents were heterozygous carriers of this mutation. In this patient, an additional mutation was also detected in the protein C gene: the heterozygous deletion of exon 7 at position 6161-6163 or 6164-6166, resulting the deletion of one amino acid (Lys150 or 151). His mother was also a carrier of this mutation. As the simultaneous mutation of the fibrinogen alpha chain and protein C genes has not been previously reported, the influence of the interaction between these two mutations on the clinical manifestations of this patient should be carefully monitored for a long period.
- Published
- 2002
26. Restricted diversification of T-cells in chronic active Epstein-Barr virus infection: potential inclination to T-lymphoproliferative disease
- Author
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Shouichi Ohga, Akihiko Nomura, Nobuhiro Kimura, Hidetoshi Takada, Shunji Yamamori, Kenji Muraoka, Toshiro Hara, Mituyuki Nagano, Hiromichi Take, and Kohichi Ohshima
- Subjects
Male ,Epstein-Barr Virus Infections ,Herpesvirus 4, Human ,Adolescent ,T-Lymphocytes ,Hepatosplenomegaly ,Receptors, Antigen, T-Cell ,Biology ,medicine.disease_cause ,Antibodies, Viral ,Gene Rearrangement, T-Lymphocyte ,Polymerase Chain Reaction ,Herpesviridae ,Virus ,Superantigen ,medicine ,Humans ,Child ,Cytopenia ,T-cell receptor ,Hematology ,DNA ,medicine.disease ,Virology ,Epstein–Barr virus ,Lymphoproliferative Disorders ,Blotting, Southern ,Immunology ,Chronic Disease ,DNA, Viral ,Splenomegaly ,Female ,Viral disease ,medicine.symptom ,Hepatomegaly - Abstract
To assess the abnormal T-cell expansion in chronic active Epstein-Barr virus infection (CAEBV), T-cell antigen receptor (TCR) repertoire was analyzed in four patients with the disease. All fulfilled the diagnostic criteria of CAEBV, presenting with fever, hepatosplenomegaly, cytopenia, abnormal high titers of anti EBV-antibodies, and positive EBV genome of unknown cause. Southern blotting probed with EBV-terminal repeats and TCR Cbeta gene indicated clonal expansion of the infected cells in 3 and 2 patients, respectively. The number of CD4+ HLA-DR+ cells appreciably increased in patients 1 (59%) and 2 (24%), who had a coronary aneurysm and central nervous system involvement, respectively. TCR gene expression examined by the inverse polymerase chain reaction methods revealed that Vbeta gene usages were preferential in all patients (Vbeta7 and Vbeta12: patient 1, Vbeta4: patient 2, Vbeta13: patients 3 and 4), compared with those in healthy controls. Valpha18 gene expression was remarkably high in patients 1 and 2. Moreover, Jbeta gene expression was skewing in the reigning Vbeta clones in all patients. Vbeta4-Jbeta1.5 and Vbeta13-Jbeta1.5 genes were clonally expressed in patients 2 and 4, respectively. These results suggest that CAEBV is associated with the restricted diversity of T-cells, which may stem from the sustained expansion of oligoclonal T-cells possibly driven by conventional viral antigens, but not, superantigens. Although the study is limited by the small number of patients, the unbalanced T-cell repertoire might contribute to the evolution of T-lymphoproliferative disease, otherwise, imply the innate defective immunity to EBV in CAEBV patients.
- Published
- 1999
27. Soluble interleukin-6 (IL-6) receptor with IL-6 stimulates megakaryopoiesis from human CD34(+) cells through glycoprotein (gp)130 signaling
- Author
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Xingwei Sui, Kohichiro Tsuji, Yasuhiro Ebihara, Ryuhei Tanaka, Kenji Muraoka, Makoto Yoshida, Kaoru Yamada, Kiyoshi Yasukawa, Tetsuya Taga, Tadamitsu Kishimoto, and Tatsutoshi Nakahata
- Subjects
Membrane Glycoproteins ,Interleukin-6 ,Immunology ,Lysosome-Associated Membrane Glycoproteins ,Antigens, CD34 ,Cell Differentiation ,Cell Biology ,Hematology ,Fetal Blood ,Hematopoietic Stem Cells ,Biochemistry ,Receptors, Interleukin-6 ,Recombinant Proteins ,Thrombopoietin ,Antigens, CD ,Humans ,Interleukin-3 ,Megakaryocytes ,Signal Transduction - Abstract
We have recently shown that stimulation of glycoprotein (gp) 130, the membrane-anchored signal transducing receptor component of IL-6, by a complex of human soluble interleukin-6 receptor (sIL-6R) and IL-6 (sIL-6R/IL-6), potently stimulates the ex vivo expansion as well as erythropoiesis of human stem/progenitor cells in the presence of stem cell factor (SCF). Here we show that sIL-6R dose-dependently enhanced the generation of megakaryocytes (Mks) (IIbIIIa-positive cells) from human CD34(+) cells in serum-free suspension culture supplemented with IL-6 and SCF. The sIL-6R/IL-6 complex also synergistically acted with IL-3 and thrombopoietin (TPO) on the generation of Mks from CD34(+) cells, whereas the synergy of IL-6 alone with TPO was barely detectable. Accordingly, the addition of sIL-6R to the combination of SCF + IL-6 also supported a substantial number of Mk colonies from CD34(+) cells in serum-free methylcellulose culture, whereas SCF + IL-6 in the absence of sIL-6R rarely induced Mk colonies. The addition of monoclonal antibodies against gp130 to the suspension and clonal cultures completely abrogated the megakaryopoiesis induced by sIL-6R/IL-6 in the presence of SCF, whereas an anti-TPO antibody did not, indicating that the observed megakaryopoiesis by sIL-6R/IL-6 is a response to gp130 signaling and independent of TPO. Furthermore, human CD34(+) cells were subfractionated into two populations of IL-6R-negative (CD34(+) IL-6R-) and IL-6R-positive (CD34(+) IL-6R+) cells by fluorescence-activated cell sorting. The CD34(+) IL-6R- cells produced a number of Mks as well as Mk colonies in cultures supplemented with sIL-6R/IL-6 or TPO in the presence of SCF. In contrast, CD34(+) IL-6R+ cells generated much less Mks and lacked Mk colony forming activity under the same conditions. Collectively, the present results indicate that most of the human Mk progenitors do not express IL-6R, and that sIL-6R confers the responsiveness of human Mk progenitors to IL-6. Together with the presence of functional sIL-6R in human serum and relative unresponsiveness of human Mk progenitors to IL-6 in vitro, current results suggest that the role of IL-6 may be mainly mediated by sIL-6R, and that the gp130 signaling initiated by the sIL-6R/ IL-6 complex is involved in human megakaryopoiesis in vivo.
- Published
- 1999
28. Thrombopoietin-independent effect of interferon-gamma on the proliferation of human megakaryocyte progenitors
- Author
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Xingwei Sui, Tatsutoshi Nakahata, Kenji Muraoka, Makoto Yoshida, Kaoru Yamada, Kohichiro Tsuji, Yasuhiro Ebihara, and Ryuhei Tanaka
- Subjects
Mitosis ,Stem cell factor ,Antigens, CD34 ,Platelet Glycoprotein GPIIb-IIIa Complex ,Biology ,Culture Media, Serum-Free ,Interferon-gamma ,Megakaryocyte ,medicine ,Humans ,Interferon gamma ,Progenitor cell ,Thrombopoietin ,Megakaryocytopoiesis ,Interleukin 3 ,Receptors, Interferon ,Stem Cell Factor ,Dose-Response Relationship, Drug ,Interleukin-6 ,Antibodies, Monoclonal ,Drug Synergism ,Hematology ,DNA ,Flow Cytometry ,Hematopoietic Stem Cells ,Molecular biology ,Haematopoiesis ,medicine.anatomical_structure ,Immunology ,Interleukin-3 ,Megakaryocytes ,Cell Division ,medicine.drug - Abstract
Flow cytometric study revealed that almost all CD34+ cells in human umbilical cord blood expressed interferon-gamma receptor (IFN-gammaR). To clarify the precise functional roles of IFN-gammaR in human CD34+ cells, we examined the effect of IFN-gamma alone and in combination with various cytokines on the growth of haemopoietic progenitor cells in CD34+ cells using a serum-free clonal culture. Surprisingly, IFN-gamma alone supported only megakaryocyte (MK) colonies in a dose-dependent manner with a plateau level at 1000 U/ml of IFN-gamma. IFN-gamma at 1000 U/ml induced 10 +/- 1.2 MK colonies from 1 x 10(3) CD34+ cells, whereas thrombopoietin (TPO), interleukin (IL)-3, stem cell factor (SCF) or IL-6 alone induced 22 +/- 4.0, 22 +/- 4.2, 4 +/- 0.6 and 0 MK colonies, respectively. The addition of anti-IFN-gamma monoclonal antibody (mAb) to the IFN-gamma culture completely abrogated MK colony formation, whereas the mAb had no effect on TPO-dependent production of MK colonies. In contrast, although anti-TPO polyclonal Ab almost completely blocked TPO-dependent MK colony formation, it failed to inhibit the generation of MK colonies induced by IFN-gamma, suggesting that the observed effect of IFN-gamma on the proliferation of human MK progenitor cells is independent of TPO. The addition of IFN-gamma to culture with TPO or SCF significantly augmented the development of MK colonies, whereas it did not affect IL-3-dependent MK colony formation. Additionally, IFN-gamma induced the increase of DNA content of cultured glycoprotein IIb/IIIa-positive megakaryocytes. These results suggest that IFN-gamma may have regulatory roles in human megakaryocytopoiesis.
- Published
- 1997
29. Defective response to thrombopoietin and impaired expression of c-mpl mRNA of bone marrow cells in congenital amegakaryocytic thrombocytopenia
- Author
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Toshiro Hara, Sumio Miyazaki, Eiichi Ishii, Hiroyuki Koga, Tatsutoshi Nakahata, S Yamamoto, Hideto Yamaguchi, Kenji Muraoka, and Koichiro Tsuji
- Subjects
Stem cell factor ,Biology ,Megakaryocyte ,Bone Marrow ,Proto-Oncogene Proteins ,medicine ,Humans ,Thrombopoiesis ,RNA, Messenger ,Receptors, Cytokine ,Thrombopoietin ,Megakaryocytopoiesis ,Thrombocytosis ,Infant ,Hematology ,medicine.disease ,Hematopoietic Stem Cells ,Thrombocytopenia ,Neoplasm Proteins ,Proto-Oncogene Proteins c-kit ,medicine.anatomical_structure ,embryonic structures ,Immunology ,Congenital amegakaryocytic thrombocytopenia ,Female ,Bone marrow ,Megakaryocytes ,Receptors, Thrombopoietin ,Cell Division - Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is an uncommon disorder in newborns and infants, characterized by isolated thrombocytopenia and megakaryocytopenia in the first year without physical anomalies. The defect of thrombopoiesis is not well understood. Recently, thrombopoietin (TPO), the ligand for the c-mpl receptor, was cloned. Accumulating evidence from in vitro and in vivo studies indicate that TPO plays a key role in the regulation of megakaryocytopoiesis. In this study we examined the effect of TPO on megakaryocyte colony formation from a patient with CAMT using a plasma-containing methylcellulose clonal culture. The in vitro results demonstrated a defective response to TPO in megakaryocyte colony formation from bone marrow mononuclear cells (MNC) of the patient. although interleukin-3 (IL-3) but not stem cell factor (SCF) induced only a small number of megakaryocyte colonies. These findings indicated that thrombocytopenia in CAMT could not be corrected by administration of TPO in vitro. Additionally, clonal cultures containing SCF, IL-3, IL-6 and erythropoietin showed decreased numbers of erythroid and myelocytic progenitors in the bone marrow of the patient. The serum TPO level measured by enzyme-linked immunosorbent assay was significantly higher than that in healthy controls. By PCR, marrow MNC from healthy children and from a patient with essential thrombocytosis expressed c-mpl mRNA, whereas no c-mpl mRNA was detected in marrow MNC from the patient with CAMT. There was no difference in the CD34 expression and c-kit mRNA between the CAMT patient and healthy children. The results of this study suggest that the pathophysiology in CAMT may be a defective response to TPO in haemopoietic cells through impaired expression of c-mpl mRNA.
- Published
- 1997
30. Analysis of interleukin 6 receptor and gp130 expressions and proliferative capability of human CD34+ cells
- Author
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Minoru Yoshida, Tadamitsu Kishimoto, Kaoru Yamada, Kohichiro Tsuji, Tetsuya Taga, S Tajima, Kiyoshi Yasukawa, Xingwei Sui, Kenji Muraoka, Tatsutoshi Nakahata, Ryuhei Tanaka, and Yasuhiro Ebihara
- Subjects
Adult ,Immunology ,CD34 ,Cell Culture Techniques ,Stem cell factor ,Antigens, CD34 ,Bone Marrow Cells ,Cell Count ,Biology ,Antigens, CD ,Cytokine Receptor gp130 ,Immunology and Allergy ,Humans ,Progenitor cell ,Thrombopoietin ,Erythroid Precursor Cells ,Interleukin 3 ,Stem Cell Factor ,Membrane Glycoproteins ,Interleukin-6 ,Macrophages ,Infant, Newborn ,Receptors, Interleukin ,Articles ,Fetal Blood ,Flow Cytometry ,Hematopoietic Stem Cells ,Molecular biology ,Receptors, Interleukin-6 ,Haematopoiesis ,Cell culture ,Cell Division ,Granulocytes - Abstract
We recently demonstrated that stimulation of gp130 by a combination of soluble interleukin 6 receptor (sIL-6R) and IL-6 but not IL-6 alone significantly stimulates the ex vivo expansion of primitive hematopoietic progenitors and the generation of erythroid cells from human CD34+ cells in the presence of stem cell factor (SCF). Here, we show that gp130 is found low positively on most CD34+ cells, whereas IL-6R is expressed on only 30-50% of these cells. Although most of the colonies generated from FACS-sorted CD34+IL-6R+ cells were granulocyte/macrophage (GM) colonies, CD34+IL-6R- cells gave rise to various types of colonies, including erythroid bursts, GM, megakaryocytes, and mixed colonies in methylcellulose culture with a combination of IL-6, sIL-6R, and SCF. Similar results were obtained in culture supplemented with a combination of IL-3, IL-6, SCF, granulocyte colony-stimulating factor, erythropoietin, and thrombopoietin. A limiting dilution analysis of long-term culture-initiating cells (LTC-IC) showed that the CD34+IL-6R- cells contained a larger number of LTC-IC than did the CD34+IL-6R+ cells. In a serum-free suspension of CD34+IL-6R- cells, the addition of sIL-6R to the combination of IL-6 and SCF dramatically increased the total and multipotential progenitors, whereas CD34+IL-6R+ cells failed to do so under the same conditions. These results indicate that most of the erythroid, megakaryocytic, and primitive human hematopoietic progenitors are included in the IL-6R- populations, and the activation of gp130 on these progenitors can be achieved by a complex of IL-6-sIL-6R, but not by IL-6 alone. The present culture system using IL-6, sIL-6R, and SCF may provide a novel approach for ex vivo expansion of human primitive hematopoietic progenitors.
- Published
- 1996
31. Characterization of peripheral blood progenitor cells (PBPC) mobilized by filgrastim (rHuG-CSF) in normal volunteers: dose-effect relationship for filgrastim with the character of mobilized PBPC
- Author
-
Kenji Muraoka, Tatsutoshi Nakahata, Jun Aizawa, Kenji Ikebuchi, Ryuhei Tanaka, Yasuhiro Ebihara, Kohichiro Tsuji, Kazuo Kodama, Fumimaro Takaku, and Tadahiro Matsudaira
- Subjects
Adult ,Male ,Filgrastim ,Microgram ,medicine.medical_treatment ,CD34 ,Antigens, CD34 ,Pharmacology ,Subcutaneous injection ,Granulocyte Colony-Stimulating Factor ,medicine ,Humans ,Progenitor cell ,Cells, Cultured ,Dose-Response Relationship, Drug ,business.industry ,Hematology ,Flow Cytometry ,Hematopoietic Stem Cells ,Recombinant Proteins ,Granulocyte colony-stimulating factor ,Cytokine ,Immunology ,Stem cell ,business ,medicine.drug - Abstract
Filgrastim (rHuG-CSF)-mobilized peripheral blood progenitor cells (PBPC) in healthy Japanese volunteers were characterized in detail using two clonal cell culture systems and double-colour flow cytometry to detect multilineage colony-forming cells and subsets of CD34+ cells. The kinetics of PBPC during the administration of filgrastim was studied, and possible differences in the character of progenitor cells relative to given doses of filgrastim were investigated. Filgrastim was administered subcutaneously to normal volunteers for 7 d at doses of 100, 200 or 400 microgram/m2 (10 per cohort). Treatment with 100 or 200 microgram/m2 filgrastim was well tolerated; however, the 400 microgram/m2 dose level was not completed because of bone pain and myalgia. The treatment strikingly mobilized various types of progenitor cells, including highly proliferative megakaryocytic colony-forming cells. The number of progenitor cells peaked on days 5 and 6. The fold increase of circulating progenitor cells from the baseline value in the volunteers treated with 200 microgram/m2 filgrastim was more pronounced than in those treated with 100 microgram/m2. Treatment with 200 microgram/m2 also released the less mature progenitor cells (i.e. mixed colony-forming cells CD34+/33- cells, and CD34+/HLA-DR-cells) into circulation better than the 100 microgram/m2 dose. These results suggest that daily subcutaneous injection with 200 microgram/m/2 filgrastim for 5 d will effectively mobilize, both qualitatively and quantitatively, PBPC in healthy donors.
- Published
- 1996
32. Role of glycoprotein 130 and c-Kit signaling in proliferation and differentiation of human hematopoietic progenitor cells
- Author
-
Yasuhiro Ebihara, Tatsutoshi Nakahata, Kohichiro Tsuji, Kenji Muraoka, S Tajima, Xingwei Sui, and Ryuhei Tanaka
- Subjects
Pharmacology ,Cancer Research ,Stem Cell Factor ,Interleukin-6 ,Cellular differentiation ,CD34 ,Stem cell factor ,Antigens, CD34 ,Cell Differentiation ,Biology ,Toxicology ,Glycoprotein 130 ,Fetal Blood ,Hematopoietic Stem Cells ,Molecular biology ,Haematopoiesis ,Oncology ,Humans ,Pharmacology (medical) ,Progenitor cell ,Signal transduction ,Stem cell ,Cell Division ,Glycoproteins ,Signal Transduction - Abstract
Glycoprotein (gp) 130, a receptor component for interleukin 6 (IL-6), can associate with a soluble IL-6 receptor (sIL-6R) – IL-6 complex. To examine the role of gp130 signaling in human hematopoietic progenitor-cell proliferation and differentiation, we studied the effects of the sIL-6R – IL-6 complex in combination with other cytokines on human CD34+ cells in clonal and suspension cultures. The sIL-6R – IL-6 complex, but not sIL-6R or IL-6 alone, in the presence of stem-cell factor (SCF) produced dramatic increases in the populations of various cell lineages, including erythroid cells and various hematopoietic progenitors, in suspension culture. Significant numbers of colonies of (particularly) multilineage and blast cells were generated in methylcellulose culture supplemented with a combination of sIL-6R – IL-6 complex and SCF. Addition of anti-gp130 monoclonal antibodies (MAbs) and anti-IL-6R MAbs to the above-mentioned cultures dose-dependently inhibited the generation of cells of various lineages and of progenitor cells in suspension culture and completely blocked multilineage colony production in methylcellulose culture; an anti-erythropoietin antibody did not cause inhibition. These findings demonstrate that both proliferation and differentiation of hematopoietic progenitor cells can be induced through gp130 and c-Kit signaling, indicating that progenitor cells are responsive to the sIL-6R – IL-6 complex, even though they do not express IL-6R. Together with previous studies showing that detectable levels of sIL-6R, IL-6, and SCF are present in human serum, these results suggest that gp130 signaling may play an important role in human hematopoiesis in vivo.
- Published
- 1996
33. [Untitled]
- Author
-
Tatsutoshi Nakahata, Kenji Muraoka, Tahara Tomoyuki Tahara, Akira Ishiguro, Yuji Inaba, Takashi Kato, Hiroshi Miyazaki, and Toshikazu Shimbo
- Subjects
medicine.medical_specialty ,business.industry ,food and beverages ,hemic and immune systems ,Hematology ,medicine.disease ,Gastroenterology ,Severe thrombocytopenia ,In vitro ,medicine.anatomical_structure ,Megakaryocyte ,hemic and lymphatic diseases ,Internal medicine ,embryonic structures ,Platelet production ,medicine ,Platelet ,Achondroplasia ,business ,Nephritis ,Thrombopoietin - Abstract
Thrombopoietin (TPO), produced mainly in the liver, is a major regulator of platelet production. Serum TPO levels are generally increased in thrombocytopenia. We report a case of a 12-year-old boy with chronic severe thrombocytopenia, achondroplasia and nephritis. Severe chronic thrombocytopenia was found at 9 months of age. It was resistant to any treatment. Studies on megakaryocytic colonies in vitro revealed that the marrow cells responded well to TPO and no plasma inhibitor was found. Although hepatic function test results were normal, serum TPO levels in the patient (0.94 fmol/ml) were consistent with those in age-matched children (0.49-1.75 fmol/ml). Chronic thrombocytopenia requires individual evaluation before clinical trials with TPO.
- Published
- 1997
- Full Text
- View/download PDF
34. Examination of a 2-Equation Model of Turbulence for Calculating the Viscous Flow around Ships
- Author
-
Kenji Muraoka
- Subjects
Physics::Fluid Dynamics ,Boundary layer ,Classical mechanics ,Flow velocity ,K-epsilon turbulence model ,Turbulence ,Turbulence kinetic energy ,Turbulence modeling ,Potential flow around a circular cylinder ,Mechanics ,K-omega turbulence model ,Mathematics - Abstract
This paper is concerned with the calculation method of viscous flow around ships based on the assumption of partially parabolic flow and the K epsilon model of turbulence (Spalding 1975, Muraoka 1979). Inlet conditions for the K epsilon model of turbulence are improved in comparison with the previous paper (Muraoka 1979). The validity of K epsilon model of turbulence is examined through calculating the flow around the axisymmetric bodies and comparing the results with the experiment of Huang et al. (1978). The results give fine agreements with the experiment in not only velocity profile and pressure variation but also turbulent properties when it adopts reasonable conditions at inlet plane. The examination is extended to the flow around ships, and the results are that the agreement of velocity profiles between calculation and experiment is better than that in the previous paper and that the turbulent properties seem to represent the phenomena. It can be believed that the 2-equation model of turbulence is a more useful tool than any other 0- or 1-equation model in considering the turbulence around ships. (Author)
- Published
- 1980
- Full Text
- View/download PDF
35. Wake Distribution of Ship and Model on Full Ship Form
- Author
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Masaaki Namimatsu, Seiya Yamashita, Kenji Muraoka, and Hitoshi Kushimoto
- Subjects
Engineering ,business.industry ,Flow (psychology) ,Pitot tube ,Wake ,Response amplitude operator ,Pressure sensor ,law.invention ,Vortex ,Stern ,Distribution (mathematics) ,law ,business ,Marine engineering - Abstract
In order to investigate the wake distribution of full ships, the measurements of the flow around the sterns of a ship and its model were carried out with five-hole pitot tubes. On the ship, a 200, 000 D. W. T. tanker, the measured section was situated at about 4. 5% of Lpp forward from A. P., and on the model some other sections were added besides the corresponding one.The pressures through the five-hole pitot tubes were measured by using the auto-balancing pressure transducers and the digital record system.From the experimental results it was confirmed that the complicated flow, so-called stern vortex, existed in the ship wake as well as in the model wake and the method to estimate the wake distribution of a ship from that of the model, which Dr. Sasajima had presented, was good for such a full ship. Moreover, when applying this method to the estimation of the directions of flow in the ship wake, the estimated directions of flow were in considerable agreement with the experimental values.
- Published
- 1973
- Full Text
- View/download PDF
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