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Shin-Ichiro Nishimura

Publications and source records attributed to Shin-Ichiro Nishimura.

At least 73 records · Page 4Linked to original sources
PubMed2004

Structural assignment of isomeric 2-aminopyridine-derivatized oligosaccharides using MSn spectral matching.

Two isomeric pairs of 2-aminopyridine (PA)-derivatized fucosylated and non-fucosylated oligosaccharides (complex-type N-glycans of IgG) were analyzed using liquid chromatography/ion trap mass spectrometry (LC/ITMS) with a sonic spray ionization source and by varying the collision-induced dissociation voltage. Reproducibility of MS(n) (n = 2) spectra obtained by LC/ITMS was tested considering both fragment ions (m/z) and intensities. A comparison of their MS(n) spectra and evaluation of similarities (or matching), based on correlation coefficients between MS(n) spectra, was investigated as a possibility for structural assignment of the isomers. It is shown that such MS(n) spectral matching is useful and applicable to the structural assignment of relatively large fucosylated and sialylated PA-oligosaccharides released from IgG based on Bn- and Yn-type fragmentations of the corresponding [M+H+Na](2+) ions.

Aminopyridines↗
PubMed2003

An engineered hyaluronan synthase: characterization for recombinant human hyaluronan synthase 2 Escherichia coli.

The Class I hyaluronan synthase (HAS) is a unique glycosyltransferase synthesizing hyaluronan (HA), a polysaccharide composed of GlcUA and GlcNAc, by using one catalytic domain that elongates two different monosaccharides. As for the synthetic mechanism, there are two alternative manners for the sugar elongation process. Some bacterial HASs add new sugars to the non-reducing end of the acceptor to grow polymers. On the other hand, some vertebrate enzymes seem to transfer sugars to the reducing end. Expression of vertebrate HASs as active and soluble proteins will accelerate further precise insight into mechanisms of sugar elongation reactions by natural HASs. Since large scale production of HA polymers and oligomers would become powerful tools both for basic studies and new biotechnology to create functional carbohydrates in medicinal purposes, advent of an efficient method for the expression of HASs in Escherichia coli is strongly expected. Here we communicate the first success of the production of recombinant human HAS2 proteins composed of only the catalytic region in E. coli as the active form. It was demonstrated that an engineered HAS2 expressed in E. coli exhibited significant activity to synthesize a mixture of HAS oligomers from 8-mer (HA8) to 16-mer (HA16). Engineered HAS2 prepared herein elongated sugars from exogenous tetrasaccharide to form polymers with a direction to the non-reducing end. According to the present results, large scale production of engineered recombinant HASs is to be performed using E. coli that will provide practical and economic advantages in manufacturing enzymes for use in the synthesis of various oligomeric HA molecules and their industrial applications.

Catalytic Domain↗
PubMed2003

Design, synthesis, and evaluation of beta-galactosylceramide mimics promoting beta-glucocerebrosidase activity in keratinocytes.

We have established an efficient synthesis of mimics of beta-galactosylceramide (beta-GalCer) increasing a beta-glucocerebrosidase (beta-GlcCer'ase) activity that associates with the skin barrier function. Among the synthetic beta-GalCer analogues (6a-6e) described herein, compound 6e exhibited a potent effect on the activation of beta-GlcCer'ase function in vitro and reduced the transepidermal water loss (TEWL) level in a UVB-induced barrier disrupted mice model. These findings indicated that compound 6e could be useful for cosmetics and medicines to improve skin barrier function.

Animals↗
PubMed2003

Detection of genes with tissue-specific expression patterns using Akaike's information criterion procedure.

We applied a method based on Akaike's information criterion (AIC) to detect genes whose expression profile is considerably different in some tissue(s) than in others. Such observations are detected as outliers, and the method we used was originally developed to detect outliers. The main advantage of the method is that objective decisions are possible because the procedure is independent of a significance level. We applied the method to 48 expression ratios corresponding to various tissues in each of 14,610 clones obtained from the RIKEN Expression Array Database (READ; http://read.gsc.riken.go.jp). As a result, for several tissues (e.g., muscle, heart, and tongue tissues that contain similar cell types) we objectively obtained specific clones without any "thresholding." Our study demonstrates the feasibility of the method for detecting tissue-specific gene expression patterns.

Algorithms↗
PubMed2003

Cell wall engineering of living bacteria through biosynthesis.

Cell wall precursors that have been modified at their peptide moiety were incorporated into the living bacterial cell wall. Using chemically synthesized bacterial cell wall precursors, a variety of compounds could be attached to the bacterial surface. Escherichia coli took the modified precursors into the cell wall after EDTA treatment, whereas lactobacilli took the compounds more effectively without EDTA treatment. Microscopic observation showed that the incorporated ketone moiety retained its reactivity. On the basis of this strategy, any compound can be displayed on the bacterial surface. This strategy for bacterial cell surface engineering will open the door for new technologies and therapies utilizing bacteria.

Bacteria↗
PubMed2003

Determination of etoposide serum concentrations in small pediatric samples by an improved method of reversed-phase high-performance liquid chromatography.

Several specific assays have been developed for the measurement of etoposide in biological fluids. As large samples are required for high sensitivity, these systems are not appropriate for a pediatric practice. In the present study, however, an improved method for the determination of serum levels of the anticancer drug etoposide was developed, using high-performance liquid chromatography with fixed-wavelength ultraviolet detection. Etoposide was extracted from serum using dichloromethane. The efficiency of extraction from serum was 85.7 +/- 7.7% for etoposide and 81.1 +/- 8.4% for diphenylhydantoin, the internal standard. The serum concentrations of etoposide were measured in 0.2-ml serum samples. The lower limit of detection was 50 ng/ml. Each measurement was completed within 5 min. The linear quantitation range for etoposide was 0.05-50 microg/ml. This assay presents an alternative method for routine measurement of serum levels of etoposide in the pediatric oncology setting.

Antineoplastic Agents, Phytogenic↗
PubMed2002

Inhibition of adhesion of type 1 fimbriated Escherichia coli to highly mannosylated ligands.

The inhibitory potencies of a number of mannosides, di- and trivalent mannosides, a set of mannose-terminating dendrimers, and five types of mannose-bearing neoglycoproteins were determined by using a binding assay that measures the binding of (125)I-labeled, highly mannosylated neoglycoprotein to a type 1 fimbriated Escherichia coli (K12) strain in suspension. The IC(50) values (the concentration of inhibitor that causes 50 % reduction in the bound (125)I-ligand to E. coli) obtained by this method were much lower than the equivalent values obtained by hemagglutination or in assays that involve microplate immobilization. Two important factors that strongly influence the affinity to E. coli adhesin are: 1) the presence of an alpha-oriented aglycon that has a long aliphatic chain or an aromatic group immediately next to the glycosyl oxygen, and 2) the presence of multiple mannosyl residues that can span a distance of 20 nm or longer on a relatively inflexible structure. The two best inhibitors, which are a highly mannosylated neoglycoprotein with the longest linking arm between a mannose and protein amino group and the largest mannosylated dendrimer (fourth generation), exhibited sub-nM IC(50) values.

Adhesins, Escherichia coli↗
PubMed2002

Cell-wall engineering of living bacteria.

The cell walls of living bacteria were chemically modified by adding cell-wall precursors. As the precursors to be incorporated into the cell wall, UDP-MurNAc pentapeptide, lipid I, and lipid II derivatives were synthesized. The aimed compounds were attached to the amine residue of lysine at the pentapeptide moiety. Fluorescein-attached UDP-MurNAc pentapeptide was efficiently incorporated into both Gram-positive and Gram-negative bacteria. In the case of Gram-negative bacteria, such as Escherichia coli, the permeability of the outer membrane (lipopolysaccharide layer) was enhanced by EDTA treatment before the incorporation. For Gram-positive bacteria, UDP-MurNAc derivatives were incorporated in the cell wall without EDTA treatment due to the lack of the lipopolysaccharide layer. Furthermore, instead of dyes, a ketone group was attached to the UDP-MurNAc pentapeptide. The ketone group was also delivered to the bacterial cell wall of lactic acid bacteria, giving a platform to attach large molecules on the surface.

Bacteria↗
PubMed2002

Germ cell survival through carbohydrate-mediated interaction with Sertoli cells.

Spermatogenesis is a precisely regulated process in which the germ cells closely interact with Sertoli cells. The molecular basis of this cell-cell adhesion is unknown. Here, we demonstrate that targeted disruption of Man2a2, a gene encoding alpha-mannosidase IIx (MX), an enzyme that forms intermediate asparagine-linked carbohydrates (N-glycans), results in Man2a2 null males that are largely infertile. The Man2a2 null spermatogenic cells fail to adhere to Sertoli cells and are prematurely released from the testis to epididymis. We identified an N-glycan structure that plays a key role in germ cell-Sertoli cell adhesion and showed that a specific carbohydrate was required for spermatogenesis.

Acetylglucosamine↗
PubMed2002

Risk-directed treatment of infant acute lymphoblastic leukaemia based on early assessment of MLL gene status: results of the Japan Infant Leukaemia Study (MLL96).

We studied the effectiveness of risk-directed therapy for infants younger than 13 months of age with acute lymphoblastic leukaemia (ALL). Fifty-five infants were assigned to different treatment programs (from December 1995 to December 1998) on the basis of their MLL gene status at diagnosis. Forty-two cases (76.3%) had a rearranged MLL gene (MLL+) and were treated with remission induction therapy followed by sequential intensive chemotherapy, including multiple genotoxic agents (MLL9601 protocol). Haematopoietic stem cell transplantation (HSCT) was attempted if suitable donors were available. Thirteen infants (23.7%) were classified as MLL- and treated for 2.5 years with intensive chemotherapy for high-risk B-ALL (MLL9602 protocol). Complete remission was induced in 38 of the 42 infants (90.5%) with MLL+ ALL and in all 13 patients (100%) with MLL- disease. In the MLL+ subgroup, the estimated event-free survival (EFS) rate at 3 years post diagnosis was 34.0% +/- 7.5%, compared with 92.3% +/- 7.4% in the MLL- subgroup (overall comparison, P = 0.001 by log-rank analysis). Both age less than 6 months (hazard ratio = 6.87, 95% CI = 0.91-52.3; P = 0.013) and central nervous system (CNS) involvement at diagnosis (hazard ratio = 2.92 95% CI = 1.29-6.63; P = 0.015) were significant independent predictors of an inferior outcome. These findings indicate a strategic advantage in classifying infant ALL as either MLL+ or MLL- early in the clinical course and selecting therapy accordingly. Standard chemotherapy for high-risk B-lineage ALL appeared adequate for MLL- cases. Novel therapeutic initiatives are warranted for infants with MLL+ disease, particularly those with initial CNS leukaemic involvement or age less than 6 months, or both.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

High-dose chemotherapy in children with metastatic hepatoblastoma.

BACKGROUND: Despite the advent of effective chemotherapy,a poor prognosis has been reported for patients with metastatic hepatoblastoma. To improve this prognosis, we conducted high-dose chemotherapy with autologous bone marrow rescue in patients with metastatic hepatoblastoma. METHODS AND RESULTS: Three patients were treated with high-dose chemotherapy. In patient 1, high-dose chemotherapy was given after the patient's first pulmonary relapse. Additional pulmonary metastases, which developed more than 6 months after high-dose chemotherapy, were treated by multiple thoracotomy without additional chemotherapy. Patient 2 presented additional pulmonary metastases soon after the end of the first thoracotomy and high-dose chemotherapy. Because of a decreased serum alpha-fetoprotein level after re-excision of the pulmonary metastases, a second round of high-dose chemotherapy was performed. In patient 3, multiple pulmonary metasteses responded to preoperative chemotherapy and disappeared according to the chest computed tomography. Intensive treatment with a high-dose chemotherapeutic regimen was performed at the end of postoperative chemotherapy. All three patients are alive and well, more than 6 years after receiving their diagnosis. CONCLUSION: The role of high-dose chemotherapy in treatment of metastatic hepatoblastoma could not be clarified,because of the small number of patients. However, the better outcome of our patients indicates that multimodal therapy, including high-dose chemotherapy, may improve the outcome of the patients with metastatic hepatoblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Low plasma levels of hemostatic proteins during the induction phase in children with acute lymphoblastic leukemia: A retrospective study by the JACLS. Japan Association of Childhood Leukemia Study.

BACKGROUND: Thromboembolic and bleeding events are serious complications associated with the administration of L-asparaginase (ASP) during the induction phase in children with acute lymphoblastic leukemia (ALL). Prophylactic supplementation of plasma-derived coagulation products remains controversial. The purposes of this study were to examine the plasma levels of hemostatic proteins during the induction phase and the efficacy of prophylactic replacement of plasma-derived products. METHODS: A multicenter retrospective survey on the incidence of hemostatic complications and the frequency of prophylactic replacement of plasma-derived products among children with ALL who under went ASP therapy was conducted. All patients were treated according to the Japan Association of Childhood Leukemia Study (JACLS) ALL-97 protocol. RESULTS: Thirty-six (67%) of the 54 JACLS-treatment centers responded and provided information on 127 patients. Clinically relevant hemostatic complications occurred in two patients (1.6%;2/127); one patient suffered intracranial bleeding 5 days after beginning the protocol, and the second patient suffered an ischemic attack during an ASP treatment. The administration of ASP(10 000 u/m2 x six doses) led to significant reductions in the plasma fibrinogen (180 +/- 74 to 105 +/- 57 mg/dL),antithrombin III (AT III) (126 +/- 21 to 73 +/- 18%),and plasminogen levels (97 +/- 17 to 52 +/- 18%). These laboratory parameters returned to normal levels 2 weeks after completion of the ASP treatment. Forty-eight patients (38%)received AT III concentrate (AT III-supplement group). The AT III level of the AT III-supplement group was significantly lower than that of the AT III non-supplement group, not only during the ASP therapy, but also prior to the ASP therapy. A greater percentage of patients in the AT III-supplement group received fresh-frozen plasma and in greater amounts than those in the AT III non-supplement group. CONCLUSIONS: Severe hemorrhage and thrombosis were uncommon in the ALL patients who underwent ASP therapy in comparison with the degree of coagulation changes. Prophylactic administration of AT III concentrate or fresh-frozen plasma did not demonstrate clear beneficial effects in the treatment of ALL in preventing thromboembolic events.

Antineoplastic Agents↗