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Kenji Saito

Publications and source records attributed to Kenji Saito.

18 recordsLinked to original sources
PubMed2006

Electron-transfer reduction of cup-stacked carbon nanotubes affording cup-shaped carbons with controlled diameter and size.

The electron-transfer reduction of cup-stacked carbon nanotubes (CSCNTs) with sodium naphthalenide and the subsequent treatment with 1-iodododecane results in electrostatically destacking of CSCNTs to afford cup-shaped carbons with controlled diameter and size. The dodecylated cup-shaped carbons were highly dispersed and stable in nonpolar solvents, such as THF, tetrachloroethylene, and chloroform, as compared with the pristine CSCNTs.

Journal Article↗
PubMed2006

Crystallization and preliminary X-ray diffraction study of an active-site mutant of pro-Tk-subtilisin from a hyperthermophilic archaeon.

Crystallization of and preliminary crystallographic studies on an active-site mutant of pro-Tk-subtilisin from the hyperthermophilic archaeon Thermococcus kodakaraensis were performed. The crystal was grown at 277 K by the sitting-drop vapour-diffusion method. Native X-ray diffraction data were collected to 2.3 A resolution using synchrotron radiation from station BL41XU at SPring-8. The crystal belongs to the orthorhombic space group I222, with unit-cell parameters a = 92.69, b = 121.78, c = 77.53 A. Assuming the presence of one molecule per asymmetric unit, the Matthews coefficient V(M) was calculated to be 2.6 A(3) Da(-1) and the solvent content was 53.1%.

Archaeal Proteins↗
PubMed2006

Stereoselective preparation, structures, and reactivities of phosphine-bridged mixed-metal trinuclear and pentanuclear complexes with tris[2-(diphenylphosphino)ethyl]phosphine.

The phosphine-bridged linear trinuclear and pentanuclear complexes with Pd(II)-Pt(II)-Pd(II), Ni(II)-Pt(II)-Ni(II), and Rh(III)-Pd(II)-Pt(II)-Pd(II)-Rh(III) metal-ion sequences were almost quantitatively formed by the stepwise phosphine-bridging reaction of the terminal phosphino groups of tris[2-(diphenylphosphino)ethyl]phosphine (pp3), which is the tetradentate bound ligand of the starting Pd(II) and Ni(II) complexes. The solid-state structures of the trinuclear complexes were determined by X-ray structural analyses, and the structures of the polynuclear complexes in solution were characterized by NMR spectroscopy. The trans and cis isomers of the trinuclear and pentanuclear complexes, which arise from the geometry around the Pt(II) center, were selectively obtained simply by changing the counteranion of the starting complexes: the tetrafluoroborate salts, [MX(pp3)](BF4) [M = Pd(II) or Ni(II), X = Cl- or 4-chlorothiophenolate (4-Cltp-)], gave only the trans isomers, and the chloride salt, [PdCl(pp3)]Cl, gave only the cis isomers. The formation of the trinuclear complex with the 4-Cltp- and chloro ligands, trans-[Pt(4-Cltp)2{PdCl(pp3)}2](BF4)2, proceeded with exchange between the thiolato ligand in the starting Pd(II) complex, [Pd(4-Cltp)(pp(3))](BF4), and the chloro ligands in the starting Pt(II) complex, trans-[PtCl2(NCC6H5)2], retaining the trans geometry around the Pt(II) center. In contrast, the formation reaction between [PdCl(pp3)]Cl and trans-[PtCl2(NCC6H5)2] was accompanied by the trans-to-cis geometrical change on the Pt(II) center to give the trinuclear complex, cis-[PtCl2{PdCl(pp3)}2]Cl2. The mechanisms of these structural conversions during the formation reactions were elucidated by the 31P NMR and absorption spectral changes. The differences in the catalytic activity for the Heck reaction were discussed in connection with the bridging structures of the polynuclear complexes in the catalytic cycle.

Journal Article↗
PubMed2006

Olfactory dysfunction in leprosy.

Leprosy (Hansen's disease) is associated with a high incidence of nasal pathology. Despite this fact, the influence of this disorder on the sense of smell is poorly understood. In this study, we administered a standardized 12-item odor identification test to 77 patients with three types of leprosy: tuberculoid (n = 9), borderline (n = 42), and lepromatous (n = 26). All three types exhibited significantly lower test scores than their respective age-, sex-, and smoking-habit-matched controls. Patients with lepromatous leprosy exhibited significantly lower test scores than those with the other two types. Only patients with lepromatous leprosy exhibited meaningful improvement in smell function after treatment. No association between disease duration, per se, and the severity of the olfactory deficit was present. Overall, 100% of the patients exhibited olfactory dysfunction, suggesting that earlier prevalence estimates based on nonstandardized olfactory testing have underestimated the prevalence of this problem.

Adult↗
PubMed2006

Ca2+-dependent maturation of subtilisin from a hyperthermophilic archaeon, Thermococcus kodakaraensis: the propeptide is a potent inhibitor of the mature domain but is not required for its folding.

Subtilisin from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 is a member of the subtilisin family. T. kodakaraensis subtilisin in a proform (T. kodakaraensis pro-subtilisin), as well as its propeptide (T. kodakaraensis propeptide) and mature domain (T. kodakaraensis mat-subtilisin), were independently overproduced in E. coli, purified, and biochemically characterized. T. kodakaraensis pro-subtilisin was inactive in the absence of Ca2+ but was activated upon autoprocessing and degradation of propeptide in the presence of Ca2+ at 80 degrees C. This maturation process was completed within 30 min at 80 degrees C but was bound at an intermediate stage, in which the propeptide is autoprocessed from the mature domain (T. kodakaraensis mat-subtilisin*) but forms an inactive complex with T. kodakaraensis mat-subtilisin*, at lower temperatures. At 80 degrees C, approximately 30% of T. kodakaraensis pro-subtilisin was autoprocessed into T. kodakaraensis propeptide and T. kodakaraensis mat-subtilisin*, and the other 70% was completely degraded to small fragments. Likewise, T. kodakaraensis mat-subtilisin was inactive in the absence of Ca2+ but was activated upon incubation with Ca2+ at 80 degrees C. The kinetic parameters and stability of the resultant activated protein were nearly identical to those of T. kodakaraensis mat-subtilisin*, indicating that T. kodakaraensis mat-subtilisin does not require T. kodakaraensis propeptide for folding. However, only approximately 5% of T. kodakaraensis mat-subtilisin was converted to an active form, and the other part was completely degraded to small fragments. T. kodakaraensis propeptide was shown to be a potent inhibitor of T. kodakaraensis mat-subtilisin* and noncompetitively inhibited its activity with a Ki of 25 +/- 3.0 nM at 20 degrees C. T. kodakaraensis propeptide may be required to prevent the degradation of the T. kodakaraensis mat-subtilisin molecules that are activated later by those that are activated earlier.

Archaeal Proteins↗
PubMed2005

A nutrigenomics database--integrated repository for publications and associated microarray data in nutrigenomics research.

In the current situation where microarray data in the field of nutritional genomics (nutrigenomics) are accumulating rapidly, there is imminent need for an efficient data infrastructure to support research workflow. We have established a web-based, integrated database of the publications and microarray expression data in the field of nutrigenomics. The registered data include links to external databases such as PubMed of the National Center for Biotechnology Information and public microarray databases that contain Minimum Information About a Microarray Experiment-compliant microarray expression data. Using this database, all data sets created will be effectively utilized and shared with other researchers. This database is built on an open-source database system and is freely accessible via the World Wide Web (http://a-yo5.ch.a.u-tokyo.ac.jp/index.phtml).

Databases, Genetic↗
PubMed2005

Elevated levels of human alpha -defensin in tears of patients with allergic conjunctival disease complicated by corneal lesions: detection by SELDI ProteinChip system and quantification.

PURPOSE: To analyze levels of alpha -defensin in the tears of allergic patients (with/without corneal lesions) comparing the results with those of normal control subjects. METHODS: Screening of the protein profiles of the tears of allergic patients with corneal epithelial lesions and normal controls was performed by surface enhanced laser desorption/ionization (SELDI) ProteinChip array initially. ELISA was then performed to quantify the levels of alpha -defensin in the tears of allergic patients (with/without corneal epithelial lesions) and normal control patients. RESULTS: Proteins expressing significant differences between patients and controls by SELDI analysis were examined. Several peptides with molecular weights similar to alpha -defensins were found to be expressed to a greater extent in allergic patients. ELISA was performed in tears of allergic patients and control subjects to ascertain the presence and increased expression of alpha -defensins in allergic patients. Concentrations of alpha -defensins in allergic patients with corneal epithelial lesions were significantly higher than those of allergic patients without epithelial lesions or normal controls. CONCLUSIONS: Alpha-defensins were found in greater concentrations in tears of allergic patients with corneal lesions. The antimicrobial effects of alpha -defensins may play a role in the prevention of secondary infection of corneal lesions in allergic patients. SELDI ProteinChip technology is a useful and effective tool in profiling the differential expression of proteins in tears.

Conjunctivitis, Allergic↗
PubMed2005

Preparation of a set of expression-ready clones of mammalian long cDNAs encoding large proteins by the ORF trap cloning method.

Although we have so far identified and sequenced >2000 human long cDNAs, known as KIAA cDNAs, half of them have yet to be functionally annotated. Expression-ready cDNA clones derived from these genes, where the open reading frame (ORF) of the gene of interest is placed under the control of an appropriate promoter, are critical for functional characterization of these gene products. In this study, we attempted to systematically convert original cDNA clones to expression-ready forms for native and fusion proteins. For this purpose, we developed a new method for ORF cloning based on a homologous recombination in Escherichia coli to avoid laborious manipulations and artificial introduction of mutations in ORF. Using 1589 putative full-length ORFs (from 1002 KIAA genes, 119 human known genes and 468 mouse genes) with an average size of 2.8 kb, we successfully prepared expression plasmids for 1463 native proteins and for 1343 fusion proteins by this method. The resultant expression-ready clones were examined using an in vitro transcription/translation system followed by SDS-polyacrylamide gel electrophoresis and by transient expression of GFP-fusion proteins in human embryonic kidney (HEK) 293 cells. This set of expression-ready clones of long cDNAs encoding large proteins would open a new route to experimentally analyze their functions on a proteomic scale, since unavailability of expression-ready clones for mammalian large proteins has been a major obstacle to the functional analysis of these cDNAs.

Animals↗
PubMed2005

A perspective on DNA microarray technology in food and nutritional science.

PURPOSE OF REVIEW: The functions of nutrients and other foods have been revealed at the level of gene regulation. The advent of DNA microarray technology has enabled us to analyze the body's response to these factors in a much more holistic manner than before. This review is intended to overview the present status of this DNA microarray technology, hoping to provide food and nutrition scientists, especially those who are planning to introduce this technology, with hints and suggestions. RECENT FINDINGS: The number of papers examining transcriptomics analysis in food and nutrition science has expanded over the last few years. The effects of some dietary conditions and administration of specific nutrients or food factors are studied in various animal models and cultured cells. The target food components range from macronutrients and micronutrients to other functional food factors. Such studies have already yielded fruitful results, which include discovery of novel functions of a food, uncovering hitherto unknown mechanisms of action, and analyses of food safety. SUMMARY: The potency of DNA microarray technology in food and nutrition science is broadly recognized. This technique will surely continue to provide researchers and the public with valuable information on the beneficial and adverse effects of food factors. It should also be acknowledged, however, that there remain problems such as standardization of the data and sharing of the results among researchers in this field.

Consumer Product Safety↗
PubMed2004

Collagen IV is essential for basement membrane stability but dispensable for initiation of its assembly during early development.

Basement membranes are specialized extracellular matrices consisting of tissue-specific organizations of multiple matrix molecules and serve as structural barriers as well as substrates for cellular interactions. The network of collagen IV is thought to define the scaffold integrating other components such as, laminins, nidogens or perlecan, into highly organized supramolecular architectures. To analyze the functional roles of the major collagen IV isoform alpha1(IV)(2)alpha2(IV) for basement membrane assembly and embryonic development, we generated a null allele of the Col4a1/2 locus in mice, thereby ablating both alpha-chains. Unexpectedly, embryos developed up to E9.5 at the expected Mendelian ratio and showed a variable degree of growth retardation. Basement membrane proteins were deposited and assembled at expected sites in mutant embryos, indicating that this isoform is dispensable for matrix deposition and assembly during early development. However, lethality occurred between E10.5-E11.5, because of structural deficiencies in the basement membranes and finally by failure of the integrity of Reichert's membrane. These data demonstrate for the first time that collagen IV is fundamental for the maintenance of integrity and function of basement membranes under conditions of increasing mechanical demands, but dispensable for deposition and initial assembly of components. Taken together with other basement membrane protein knockouts, these data suggest that laminin is sufficient for basement membrane-like matrices during early development, but at later stages the specific composition of components including collagen IV defines integrity, stability and functionality.

Animals↗
PubMed2004

[Autologous peripheral blood stem cell transplantation for Japanese multiple myeloma patients: results of a feasibility study].

A feasibility study on high-dose therapy with autologous peripheral blood stem cell transplantation (HDT/PBSCT) was performed in Japanese patients with multiple myeloma (MM). Twenty evaluable patients younger than 65 years old with stage II/III MM were enrolled in this study. Three courses of VAD were used as initial chemotherapy. High-dose etoposide or cyclophosphamide followed by G-CSF was used for PBSCH, and 1.2-89.3 (median 23.4) x 106/kg of CD34+ cells were collected. Single (11 patients) or tandem (9 patients) HDT with melphalan (MEL) 200 mg/m2 or MEL 140 mg/m2 plus TBI 10 Gy were performed. The incidence of grade 4 toxicity (COG) was 10% and treatment-related mortality was 5%. Complete response and tumor reduction of more than 75% were obtained in 4 (21%) and 16 (84%) out of 19 patients, respectively. The actuarial 3-year overall survival (OS) and event-free survival (EFS) after PBSCT/HDT were 65.6% and 22.0%, respectively. The median EFS duration was 18 months. These preliminary results indicated that HDT/PBSCT is feasible for Japanese MM patients. A prospective randomized clinical trial will be required to assess the efficacy.

Adult↗
PubMed2003

Two distinct pathways for the formation of hydroxy FA from linoleic acid by lactic acid bacteria.

Twenty-three of 86 strains of lactic acid bacteria transformed linoleic acid into hydroxy FA. Two distinct conversion pathways were in operation. Two strains of Lactobacillus acidophilus and a strain of Pediococcus pentosaceus produced 13(S)-hydroxy-9-octadecenoic acid 113(S)-OH 18:11 and 10,13dihydroxyoctadecanoic acid (10,13-OH 18:0) as main and minor products, respectively, whereas 13 strains, including L. casei subsp. casei, L. paracasei subsp. paracasei, L. rhamnosus, L. lactis subsp. cremoris, and Streptococcus salivarius subsp. thermophilus produced 10-hydroxy-12-octadecenoic acid (10-OH 18:1). Seven strains of L. plantarum converted linoleic acid to 10-hydroxyoctadecanoic acid (10-OH 18:0) through 10-OH 18:1. Linoleic acid at 2 g/L was converted by L. acidophilus IFO13951T to 1.3 g of 13(S)-OH 18:1 and 0.09 g of 10,13-OH 18:0 in 7 d. Lactobacillus paracasei subsp. paracasei JCM 1111 produced 10-OH 18:1 in 91% yield, and L. plantarum JCM 8341, 10-OH 18:0 in 59% yield from linoleic acid (2 g/L) under optimal conditions. To our knowledge, this is the first report on the production of 13(S)-OH 18:1 by lactic acid bacteria other than ruminal bacteria, and of 10,13-OH 18:0 by any bacteria.

Fatty Acids↗
PubMed2002

Basement membrane type IV collagen molecules in the choroid plexus, pia mater and capillaries in the mouse brain.

We investigated the differential distribution of basement membrane type IV collagen a chains in the mouse brain by immunohistochemistry using a chain-specific monoclonal antibodies. Subendothelial basement membranes were found to contain alpha1 and alpha2 chains. Basement membranes surrounding smooth muscle cells on blood vascular walls were immunoreactive for alpha1 and alpha2 chains but not for alpha5 and alpha6 chains. Interestingly, the pia mater contained a thin basement membrane which was positive for alpha1, alpha2, alpha5, and alpha6 chains, suggesting that glia limitans superficialis coheres basement membranes containing [alpha1(IV)]2alpha2(IV) and [alpha5(IV)]2alpha6(IV) molecules. In contrast, capillaries always possessed thin basement membranes of [alpha1(IV)]2alpha2(IV) molecules. Cerebrospinal fluid is produced through filtration of blood at the choroid plexus, where two distinct basement membranes were detected by anti-al and anti-alpha2 antibodies. The subendothelial basement membrane appeared to consist of [alpha1(IV)]2alpha2(IV) molecules, whereas the subependymal basement membrane in the choroid plexus was strongly positive for alpha3, alpha4, and alpha5 chains, indicating that the filtering unit was composed of alpha3(IV)alpha4(IV)alpha5(IV) molecules. That the specific localizations of these molecules are shared by renal glomeruli and the choroid plexus leads us to hypothesize that the supramolecular network containing alpha3(IV) alpha4(IV)alpha5(IV) molecules may function as a permeability selective barrier.

Animals↗
PubMed2002

[Development of overt hemolytic anemia after splenectomy for thrombocytopenia in Evans syndrome with negative Coombs test].

A 69-year-old man was diagnosed as having idiopathic thrombocytopenic purpura (ITP) in April 2000, and treated with prednisolone (PSL) without effect. Splenectomy performed in June 2000 had only a transient and marginal influence on his platelet count. Two months later, he developed autoimmune hemolytic anemia (AIHA) without Coombs test positivity, and his diagnosis was changed to Coombs-negative Evans syndrome. Treatment with PSL led to recovery of his hemoglobin level, but not his platelet count. Although the mechanism responsible for development of AIHA after splenectomy in this patient with ITP remains unknown, close observation is required for any association with other autoimmune diseases such as SLE.

Anemia, Hemolytic↗
PubMed2002

[WT1 gene expression in patients with acute myelogenous leukemia or high risk myelodysplastic syndrome successfully treated with the CAG regimen].

Ten patients with acute myelogenous leukemia or high risk myelodysplastic syndrome who had achieved complete remission following treatment with the CAG regimen were monitored for peripheral blood WT1 expression mRNA levels. Induction therapy with the CAG regimen did not seem to be enough to lower WT1 expression levels to the normal range. In comparison with patients who received intensive chemotherapy for post-remission therapy, those who received only CAG therapy showed higher levels of WT1 expression and more easily relapsed. These data suggest that CAG therapy alone might not be sufficient to maintain complete remission and WT1 monitoring could be useful in the choice of appropriate post-remission therapy after achieving remission with the CAG regimen.

Aclarubicin↗
PubMed2002

[Small lymphocytic lymphoma during the course of pure red cell aplasia].

A 29-year-old woman was diagnosed as having pure red cell aplasia (PRCA) in 1983. Her serum and IgG inhibited erythroid colony formation of bone marrow cells from a normal individual, suggesting antibody-mediated suppression of erythropoiesis. She was first successfully treated with corticosteroids, azathiopurine and cyclophosphamide. However, she relapsed in 1995 and her anemia became refractory to immunosuppressive therapy. In 1998, she developed systemic lymph node enlargement and was diagnosed as having B-cell small lymphocytic lymphoma. Combination chemotherapy resulted in regression of the lesion, but failed to improve the anemia. In this patient's case, we can speculate that B cells producing autoantibodies against erythroid cells have undergone transformation, or alternatively that the immunosuppressive state caused by the PRCA therapy promoted generation of a neoplastic B cell clone.

Female↗
PubMedDate not supplied

Application of a novel protein biochip technology for detection and identification of rheumatoid arthritis biomarkers in synovial fluid.

We compared protein profiles of the synovial fluid of patients with rheumatoid arthritis and osteoarthritis by using surface-enhanced laser desorption/ionization mass spectrometry technology. With this approach, we identified a protein expressed specifically in the synovial fluid of the patients with rheumatoid arthritis. During the investigation, we found several reproducible and discriminatory biomarker candidates for distinction between rheumatoid arthritis and osteoarthritis. Among these candidates, a 10 850 Da protein peak was the clearest example of a single signal found specifically in the rheumatoid arthritis samples. This candidate was purified using a size-exclusion spin column followed by gel electrophoresis and subsequently identified by peptide mapping and post-source decay (PSD) analysis. The results clearly indicate that the protein is myeloid-related protein 8, which was verified by the enzyme immunoassay. It is known that the myeloid-related protein 8 level in serum and synovial fluid is related to disease activity in juvenile rheumatoid arthritis. The results suggest that the ProteinChip platform is useful to detect and identify protein biomarkers expressed specifically in diseases or in some stage of diseases.

Arthritis, Rheumatoid↗