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Naoki Okamoto

Publications and source records attributed to Naoki Okamoto.

9 recordsLinked to original sources
PubMed2006

Induction of promotive rather than suppressive immune responses from a novel NKT cell repertoire Valpha19 NKT cell with alpha-mannosyl ceramide analogues consisting of the immunosuppressant ISP-I as the sphingosine unit.

A 2-substituted 2-aminopropane-1,3-diol or 2-aminoethanol is the minimum structure required for the immunosuppressive activity of ISP-I, an antibiotic isolated from the culture broth of Isaria sinclairil. A series of alpha-mannosyl ceramide (alpha-ManCer) analogues was derived from 2-substituted 2-aminopropane-1,3-diols or 2-aminoethanols in place of sphingosine. The newly synthesized glycosides were evaluated for their effects on immune responses. In contrast to the immunosuppressive activity of the precursors, the alpha-ManCer analogues induced immunopromotive responses from invariant Valpha19-Jalpha26 transgenic mouse lymphocytes more effectively than the original alpha-ManCer. Collectively, it is strongly suggested that the 2-substituted 2-aminopropane-1,3-diols and 2-aminoethanols mimic sphingosine in the alpha-ManCer analogues so that they potentially acquire specific antigenicity toward Valpha19 NKT cell, a novel NKT cell subset.

Animals↗
PubMed2006

A flexible representation of omic knowledge for thorough analysis of microarray data.

BACKGROUND: In order to understand microarray data reasonably in the context of other existing biological knowledge, it is necessary to conduct a thorough examination of the data utilizing every aspect of available omic knowledge libraries. So far, a number of bioinformatics tools have been developed. However, each of them is restricted to deal with one type of omic knowledge, e.g., pathways, interactions or gene ontology. Now that the varieties of omic knowledge are expanding, analysis tools need a way to deal with any type of omic knowledge. Hence, we have designed the Omic Space Markup Language (OSML) that can represent a wide range of omic knowledge, and also, we have developed a tool named GSCope3, which can statistically analyze microarray data in comparison with the OSML-formatted omic knowledge data. RESULTS: In order to test the applicability of OSML to represent a variety of omic knowledge specifically useful for analysis of Arabidopsis thaliana microarray data, we have constructed a Biological Knowledge Library (BiKLi) by converting eight different types of omic knowledge into OSML-formatted datasets. We applied GSCope3 and BiKLi to previously reported A. thaliana microarray data, so as to extract any additional insights from the data. As a result, we have discovered a new insight that lignin formation resists drought stress and activates transcription of many water channel genes to oppose drought stress; and most of the 20S proteasome subunit genes show similar expression profiles under drought stress. In addition to this novel discovery, similar findings previously reported were also quickly confirmed using GSCope3 and BiKLi. CONCLUSION: GSCope3 can statistically analyze microarray data in the context of any OSML-represented omic knowledge. OSML is not restricted to a specific data type structure, but it can represent a wide range of omic knowledge. It allows us to convert new types of omic knowledge into datasets that can be used for microarray data analysis with GSCope3. In addition to BiKLi, by collecting various types of omic knowledge as OSML libraries, it becomes possible for us to conduct detailed thorough analysis from various biological viewpoints. GSCope3 and BiKLi are available for academic users at our web site http://omicspace.riken.jp.

Journal Article↗
PubMed2005

Synthetic alpha-mannosyl ceramide as a potent stimulant for an NKT cell repertoire bearing the invariant Valpha19-Jalpha26 TCR alpha chain.

A NKT cell repertoire is characterized by the expression of the Valpha19-Jalpha26 invariant TCR alpha chain (Valpha19 NKT cell). This repertoire, as well as a well-established Valpha14-Jalpha281 invariant TCR alpha(+) NKT cell subset (Valpha14 NKT cell), has been suggested to have important roles in the regulation of the immune system and, thus, is a major therapeutic target. Here, we attempted to find specific antigens for Valpha19 NKT cells. Valpha19 as well as Valpha14 NKT cells exhibited reactivity to alpha-galactosyl ceramide (alpha-GalCer). Thus, a series of monoglycosyl ceramides with an axially oriented glycosidic linkage between the sugar and ceramide moiety were synthesized and their antigenicity to Valpha19 NKT cells was determined by measuring their immune responses in culture with glycolipids. Comprehensive examinations revealed substantial antigenic activity for Valpha19 NKT cells by alpha-mannosyl ceramide.

Animals↗
PubMed2004

Generation of Valpha14 NKT cells in vitro from hematopoietic precursors residing in bone marrow and peripheral blood.

We previously reported the generation of Valpha14 invariant TCR+ (Valpha14i) NK1.1+ natural killer T (NKT) cells in the cytokine-activated suspension culture of murine fetal liver cells. In this study, we attempted to apply this finding to the induction of Valpha14i NKT cell differentiation in the culture of hematopoietic precursors residing in bone marrow or peripheral blood. Preferential generation of NKT cells was found in the culture of Thy-1(+)-depleted bone marrow cells in the presence of culture supernatant from Con A-stimulated spleen T cells and a combination of recombinant IL-3, IL-4, IL-7 and GM-CSF. NKT cell development from peripheral blood hematopoietic precursors was induced when they were cultured on stromal cell monolayers prepared from Thy-1(+)-depleted bone marrow or fetal liver cells, suggesting that certain environments derived from hematopoietic organs are required for the induction of NKT cells from precursors in vitro. A significant fraction of NKT cells generated in the culture were positive for staining with CD1-alpha-galactosylceramide tetramer, indicating that Valpha14i NKT cells were the major subset among the NKT cells. The present methods for obtaining NKT cells in the culture of bone marrow or peripheral blood cells are applicable to the treatment of patients suffering from diseases with numerical and functional disorders of NKT cells.

Animals↗
PubMed2004

Combination chemotherapy of gemcitabine and vinorelbine for patients in stage IIIB-IV non-small cell lung cancer: a phase II study of the West Japan Thoracic Oncology Group (WJTOG) 9908.

OBJECTIVES: Vinorelbine (V) and gemcitabine (G) are two active single agents used in the treatment of non-small cell lung cancer (NSCLC). A multicenter clinical trial (West Japan Thoracic Oncology Group (WJTOG) 9908) was conducted to evaluate the efficacy and toxicity of V and G in patients (pts) with advanced NSCLC. METHODS ELIGIBILITY CRITERIA: no previous chemotherapy; performance status (PS) 0 or 1; age <75 years old. V, 25mg/m2, was given as a 2-3 min IV infusion, followed by a 30 min IV infusion of G, 1000 mg/m2, on days 1 and 8 of each 21-day cycle. RESULTS: From April 2000 to September 2000, 52 pts were enrolled in the study. Two pts were ineligible. Baseline characteristics: median age 60, males 30 (60%), Eastern Cooperative Oncology Group (ECOG) PS 0/1=21/29 (58%), stage IIIB/IV=12/38 (76%), adenocarcinoma=35 (70%). The median number of cycles administered was 2. Fifty pts were evaluable for response. The response rate was 18% by the Response Evaluation Criteria in Solid Tumors (RECIST) (no complete response (CR), 9 partial response (PR), 25 stable disease, 12 progressive disease, 4 not evaluable). Grade III/IV toxicities were as follows: neutropenia grade III/IV=66%, anemia grade III/IV=16%, thrombocytopenia grade III/IV=2%, nausea grade III/IV=10%, vomiting grade III/IV=0%, documented infection grade III/IV=10%, skin rash grade III/IV=2%, and hepatic grade III/IV=8%. There were no treatment-related deaths. The median time to progression was 4.1 months. The overall median survival time (MST) was 13.9 months (range, 2.4 to >16.2 months) with a median follow-up time of 13.9 months. The MST for stage IIIB and stage IV was >14.5 and 12.7 months, respectively. The overall estimated 1-year survival rate was 55.4%. CONCLUSIONS: This regimen has modest activity and is very well tolerated, with an encouraging 1-year survival rate.

Adult↗
PubMed2004

Automatic quantification of morphological traits via three-dimensional measurement of Arabidopsis.

Many mutants have been isolated from the model plant Arabidopsis thaliana, and recent important genetic resources, such as T-DNA knockout lines, facilitate the speed of identifying new mutants. However, present phenotypic analysis of mutant screens depends mainly on qualitative descriptions after visual observation of morphological traits. We propose a novel method of phenotypic analysis based on precise three-dimensional (3D) measurement by a laser range finder (LRF) and automatic data processing. We measured the 3D surfaces of young plants of two Arabidopsis ecotypes and successfully defined two new traits, the direction of the blade surface and epinasty of the blade, quantitatively. The proposed method enables us to obtain quantitative and precise descriptions of plant morphologies compared to conventional 2D measurement. The method will open a way to find new traits from mutant pools or natural ecotypes based on 3D data.

Algorithms↗
PubMed2004

Development of reconstituted embryos derived from somatic cell nuclei in the rabbit.

Production of cloned laboratory animals is helpful in the establishment of medical models. In this study, we examined to produce reconstituted embryos derived from somatic cell nuclei, and to establish embryonic stem (ES) cell lines from the embryo in rabbits. Metaphase II (M-II) oocytes from superovulated rabbit were used as nuclear recipients. Nuclear donor cells were fibroblasts collected from a Dutch Beleted rabbit. The M-II chromosome and the 1st polar body were aspirated, and a fibroblast was inserted into the perivitelline space of the enucleated oocyte. The pairs were electrofused for cell membrane fusion using a cell fusion apparatus, and reconstituted embryos were produced. The embryos were activated and cultured in modified HTF medium and DMEM. The embryos developed to the blastocyst stage were removed their zona pellucida, and they were cultured on the feeder cell layer. As a result of having observed development of reconstituted embryos, 21.2% of the embryos were developed to the blastocyst stage. In the embryos cultured on the feeder cells, the adhesion on feeder cells was observed. We obtained inner cell mass (ICM) colony derived from reconstituted embryos. At present, we are investigating to establish the ES cell lines derived from the embryos reconstituted by nuclear transfer.

Adenine↗