Biomedical subjects

N Sakata

Publications and source records attributed to N Sakata.

At least 19 recordsLinked to original sources

PubMed2006

High durability cementitious material with mineral admixtures and carbonation curing.

Nuclear waste repositories need highly durable cementitious materials to function for over thousands of years while resisting leaching and degradation. The durability of cementitious material can be effectively improved by reducing permeability and by changing cement hydrates to a less soluble matrix. This paper describes the properties of carbonated new cementitious materials containing belite-rich cement and gamma-2CaO.SiO2 as main components. In addition, the long-term leaching properties are investigated and compared with ordinary Portland cement by using a predictive leaching model.

Carbon↗

PubMed2006

Increased intensity of acute graft-versus-host disease after reduced-intensity bone marrow transplantation compared to conventional transplantation from an HLA-matched sibling in children.

Eight children underwent reduced-intensity stem cell transplantation (RIST) from an HLA-matched sibling. They received a fludarabine-melphalan based preparative regimen. Stem cell source was bone marrow, and GVHD prophylaxis consisted of cyclosporine A alone. Acute GVHD grade II-IV and grade III-IV were observed in four (50%) and three (37.5%), respectively, out of these eight patients. This incidence was significantly higher than that after conventional bone marrow transplantation, without severe tissue damage, in the same setting of stem cell source and GVHD prophylaxis. Although the number of patients is small, our results suggest that incidence of acute GVHD after RIST for children is significant. It should be remembered that RIST for children does not seem to be an easy transplant procedure from the viewpoint of acute GVHD, although RIST is less toxic.

Adolescent↗

PubMed2006

Simultaneous five cell-lineage flow cytometric analysis system for detection of leucocyte antibodies.

Although flow cytometric (FCM) analysis is one of the most widely used approaches to screen the presence of leucocyte antibodies, it has several drawbacks. First, neutrophils and, especially, monocytes exhibit high background reactivity. Second, to determine antibody specificity, it is often necessary to examine not only neutrophils and monocytes but also other lineage cells including T cells, B cells and platelets. Therefore, we attempted to establish an FCM analysis system in which four lineages of leucocytes and platelets are simultaneously tested with low background. FCM analysis was performed using ethylene diamine tetraacetic acid-anticoagulated whole blood as cell sample without any cell preparation. Discrimination of five cell lineages was carried out based on the differences in forward vs. side scatter distribution and in the expression of CD4, CD20 and CD14. When anti-HNA (human neutrophil antigen) 1b antiserum was applied to HNA 1b-positive blood samples, only neutrophils were unambiguously positive. When anti-Naka (anti-CD36) antiserum was applied, only platelets and monocytes were positive. The background reactivity of neutrophils and monocytes was low enough. When anti-human leucocyte antigen (HLA) class II antiserum was tested, only B-lymphocytes and monocytes were positive. When anti-HLA class I antiserum was tested, all the five-lineage cells were positive.

Antibodies↗

PubMed2006

Study of water quality distribution in Lake Biwa in consideration of runoff pollutant loads from its catchment basin.

Many strategies for water quality conservation in Lake Biwa are being carried out mainly by reducing runoff pollutant loads into the lake. But influence of the runoff load reduction on the water quality in Lake Biwa has not been clarified enough so far. This study is aimed at discussing methodology to estimate water quality distribution in Lake Biwa using runoff pollutant loads from its basin. The runoff loads from the basin are calculated by Macro Model with GIS database of the Lake Biwa basin, and the water quality distribution in the lake is estimated by the spline technique with the calculated runoff loads. As a result, it has been proved that the methodology has enough reproducibility to estimate the water quality distribution in Lake Biwa and is available to examine the water quality in the lake.

Conservation of Natural Resources↗

PubMed2005

Unrelated donor bone marrow transplantation for 100 pediatric patients: a single institute's experience.

In all, 100 unrelated donor bone marrow transplantations (UD-BMT) were performed in our institute between October 1993 and January 2003. Of 93 evaluable patients, 73 patients had hematological malignancy, 13 had nonmalignancy and seven had lymphoproliferative disease. The estimated 9-year event-free survival (EFS) rate was 57.1+/-5.5% in all patients. In the following analyses of the patients with hematological malignancy, the standard group had significantly better EFS than the high-risk group (61.5+/-7.0 vs 35.6+/-9.7%, P=0.02), and the EFS rate of the tacrolimus (FK-506)+methotrexate (MTX)+/-methylprednisolone prophylactic group for graft-versus-host disease was superior to that of the FK-506 without MTX group (75.7+/-8.0 vs 55.8+/-7.6%, P=0.02). When we compared the EFS rates of the FK506+MTX+/-methylprednisolone (mPSL) group and the HLA-matched related donor BMT group in our institute, these were almost similar (75.7+/-8.1 vs 68.4+/-9.3%). Therefore, UD-BMT using FK-506+MTX+/-mPSL is a safe and useful method for children with hematological malignancy who require allogeneic BMT.

Adolescent↗

PubMed2004

A new diagnostic test for VLCAD deficiency using immunohistochemistry.

BACKGROUND: Muscle pathology is often unhelpful in elucidating the specific underlying abnormality in patients with metabolic myopathy with rhabdomyolysis, including very-long chain acyl-CoA dehydrogenase (VLCAD) deficiency. Biochemical analyses require large amounts of biopsy samples for each enzyme assay. OBJECTIVE: To develop a more efficient diagnostic method for VLCAD deficiency. METHODS: The authors performed immunohistochemical analysis using an antibody to VLCAD on muscles from 344 patients (226 men and 118 women) without a specific diagnosis who had at least one of the following symptoms: myoglobinuria, high CK level, muscle pain, muscle stiffness, sudden infant death syndrome, and Reye-like syndrome. RESULTS: Immunoreactivity to VLCAD was absent or markedly reduced in 13 patients. Biochemical analyses confirmed that all these patients had low enzymatic activity and reduced amount of protein. They all had the myopathic phenotype. The authors identified homozygous or compound heterozygous mutations in all of them. All recombinant proteins had reduced enzymatic activity except for 128G>A (G43D) and 796C>G (P266A) mutants, indicating that they are neutral polymorphisms. CONCLUSIONS: The new screening method for the detection of VLCAD deficiency using an immunohistochemical technique identified 13 new Japanese patients with VLCAD deficiency.

Acyl-CoA Dehydrogenase, Long-Chain↗

PubMed2004

In vivo MRS measurement of liver lipid levels in mice.

A magnetic resonance spectroscopy (MRS) procedure for in vivo measurement of lipid levels in mouse liver is described and validated. The method uses respiratory-gated, localized spectroscopy to collect proton spectra from voxels within the mouse liver. Bayesian probability theory analysis of these spectra allows the relative intensities of the lipid and water resonances within the liver to be accurately measured. All spectral data were corrected for measured spin-spin relaxation. A total of 48 mice were used in this study, including wild-type mice and two different transgenic mouse strains. Different groups of these mice were fed high-fat or low-fat diets or liquid diets with and without the addition of alcohol. Proton spectra were collected at baseline and, subsequently, every 4 weeks for up to 16 weeks. Immediately after the last MRS measurement, mice were killed and their livers analyzed for triglyceride level by conventional wet-chemistry methods. The excellent correlation between in vivo MRS and ex vivo wet-chemistry determinations of liver lipids validates the MRS method. These results clearly demonstrate that in vivo MRS will be an extremely valuable technique for longitudinal studies aimed at providing important insights into the genetic, environmental, and dietary factors affecting fat deposition and accumulation within the mouse liver.

Animals↗

PubMed2004

High frequency of QPY allele and linkage disequilibrium of granzyme-B in Epstein-Barr-virus-associated hemophagocytic lymphohistiocytosis.

Mediation of Epstein-Barr virus (EBV)-specific cytotoxicity in T lymphocyte via the perforin/granzyme pathway has been demonstrated; therefore, a study involving cytolytic molecules was essential for the clarification of hemophagocytic lymphohistiocytosis (HLH) pathogenesis. This investigation, which analysed the frequency of three allelic mutations of granzyme-B (55Q/R, 95P/A and 247Y/H) in patients with EBV-HLH and infectious mononucleosis, identified the high prevalence of the QPY haplotype in EBV-HLH patients in comparison with healthy controls. A > G polymorphism was also detected in intron 5; furthermore, nearly complete linkage disequilibrium was observed among these polymorphisms. The recessive role of the QPY haplotype of granzyme-B might be responsible for the pathogenesis of EBV-HLH. Cytotoxicity and DNA fragmentation of cytotoxic T lymphocytes did not differ among patients characterized by the QPY/QPY, RAH/RAH and QPY/RAH genotypes. This finding suggested that DNA fragmentation in target cells is mediated not only by granzyme-B but also by other molecules, including other granzymes or Fas.

Genetic Predisposition to Disease↗

PubMed2003

Graft-versus-tumor effect in a patient with advanced neuroblastoma who received HLA haplo-identical bone marrow transplantation.

A 5-year-old boy received CD34-positive HLA haplo-identical bone marrow transplantation from his father as treatment for refractory advanced neuroblastoma. He had residual disease in the para-aortic lymph nodes and multiple bones after the transplant. However, all of his residual disease had disappeared completely 3 years later. He developed grade I acute graft-versus-host disease (GVHD) but had no symptoms of chronic GVHD or any other complications. This case demonstrates the possibility of a graft-versus-tumor effect against neuroblastoma by HLA-mismatched allogeneic hematopoietic stem cell transplantation.

Bone Marrow Transplantation↗

PubMed2002

Polymorphisms of transforming growth factor-beta1 and transforming growth factor-beta1 type II receptor genes are associated with acute graft-versus-host disease in children with HLA-matched sibling bone marrow transplantation.

The aim of this study was to determine whether the gene polymorphisms of Th1/Th2 and immunoregulatory cytokines were associated with aGVHD in Japanese children receiving allogeneic bone marrow transplantation (allo BMT). We investigated polymorphisms of genes encoding interleukin (IL)-4, IL-4 receptor (IL-4 R), IL-10, transforming growth factor (TGF)-beta1, TGF-beta1 type II receptor (TGF-beta1 RII), interferon (IFN)-gamma, IFN-gamma type 2 receptor (IFN-gamma R2), and IFN regulatory factor (IRF)-1. Sixty-seven patients were treated with allo BMT from HLA-identical siblings, and aGVHD was observed in 38. TGF-beta1 codon 10 leucine (Leu) /proline (Pro) polymorphism in donors was associated with the development of aGVHD. Patients having donors with the Pro allele had aGVHD more frequently than those without Pro allele (30/45 vs 8/20, odds ratio = 3.00; P = 0.04). TGF-beta1 RII 1167 C/T polymorphism in recipients was also associated with the development of aGVHD. The incidence was significantly higher in recipients with T allele than in those without T allele (21/27 vs 16/35, odds ratio = 4.16; P = 0.01). In conclusion, genetic backgrounds of TGF-beta1 and TGF-beta1 RII may be involved in the development of aGVHD in HLA-matched sibling BMT in Japanese children.

Acute Disease↗

PubMed2002

Disseminated strongyloidiasis in nephrotic syndrome.

Strongyloides stercoralis is endemic in the southwestern islands Amami and Ryukyu in Japan. Systemic strongyloidiasis occurs in immunocompromised hosts. We report here on a 60-year-old patient with minimal-change nephrotic syndrome (MCNS) without eosinophilia or HTLV-I infection. She was treated with corticosteroid for MCNS and died of disseminated strongyloidiasis. The patient developed systemic purpura, ileus, respiratory distress, malabsorption, pancytopenia, pulmonary hemorrhage and sepsis due to Escherichia coli before death. Massive infestation with Strongyloides stercoralis was disclosed by autopsy, and the larvae was considered as a pathomechanism or exacerbating agent of nephrotic syndrome in endemic areas.

Fatal Outcome↗

PubMed2001

DNA/RNA-dependent ATPase activity is associated with ATBF1, a multiple homeodomain-zinc finger protein.

The AT motif-binding factor 1 (ATBF1)-A is a large transcription factor containing four homeodomains and 23 zinc finger motifs. It has a number of motifs involved in transcriptional regulation, and in addition, several motifs found in enzymes, such as ATPases and helicases. In this study, we examined whether ATPase activity is associated with the ATBF1-A molecule. A 263-amino acid segment of the ATBF1-A molecule, termed AHZ, which contains the ATPase A-motif, homeodomain IV and zinc finger 21, was expressed in Escherichia coli in the form of glutathione S-transferase fusion protein and analyzed for ATPase activity. We found that AHZ was able to hydrolyze ATP with K(m) 10.6 microM and K(cat) 0.055 min(-1) at 5 mM Mg(2+) and pH 7.75. AHZ retained bacterial DNA and removal of the DNA resulted in 70% decrease in ATPase activity. The addition of double- or single-stranded DNAs restored 70-75% ATPase activity and that of RNA restored 50-55% activity. Site-directed mutagenesis of the A-motif resulted in 34% reduction of ATPase activity with no significant loss of bound DNA. In contrast, mutation of homeodomain IV and zinc finger 21 resulted in 90 and 80% reduction of ATPase, respectively, with the loss of the ability to bind to DNA and RNA. These results show that ATBF1 has at least one enzyme activity in addition to regulation of DNA transcription. The ATPase activity associated with ATBF1-A is DNA/RNA-dependent and unique in that it requires both homeodomain and zinc finger motifs.

Adenosine Triphosphatases↗

PubMed2001

Contribution of anaphylatoxin C5a to late airway responses after repeated exposure of antigen to allergic rats.

We attempted to elucidate the contribution of complement to allergic asthma. Rat sensitized to OVA received repeated intratracheal exposures to OVA for up to 3 consecutive days, and pulmonary resistance was then estimated for up to 6 h after the last exposure. Whereas the immediate airway response (IAR) in terms of R(L) tended to decrease in proportion to the number of OVA exposures, late airway response (LAR) became prominent only after three. Although premedication with two kinds of complement inhibitors, soluble complement receptor type 1 (sCR1) or nafamostat mesylate, resulted in inhibition of the IAR after either a single or a double exposure, the LAR was inhibited after the triple. Premedication with a C5a receptor antagonist (C5aRA) before every exposure to OVA also inhibited the LAR after three. Repeated OVA exposure resulted in eosinophil and neutrophil infiltration into the bronchial submucosa which was suppressed by premedication with sCR1 or C5aRA. Up-regulation of C5aR mRNA was shown in lungs after triple OVA exposure, but almost no up-regulation of C3aR. Pretreatment with sCR1 or C5aRA suppressed the up-regulation of C5aR expression as well as cytokine messages in the lungs. The suppression of LAR by pretreatment with sCR1 was reversed by intratracheal instillation of rat C5a desArg the action of which was inhibited by C5aRA. In contrast, rat C3a desArg or cytokine-induced neutrophil chemoattractant-1 induced cellular infiltration into the bronchial submucosa by costimulation with OVA, but these had no influence on the LAR. These differences might be explained by the fact that costimulation with OVA and C5a synergistically potentiated IAR, whereas that with OVA and either C3a or cytokine-induced neutrophil chemoattractant-1 did not. C5a generated by Ag-Ab complexes helps in the production of cytokines and contributes to the LAR after repeated exposure to Ag.

Airway Resistance↗

PubMed2001

Positive and negative regulation of myogenic differentiation of C2C12 cells by isoforms of the multiple homeodomain zinc finger transcription factor ATBF1.

The ATBF1 gene encodes two protein isoforms, the 404-kDa ATBF1-A, possessing four homeodomains and 23 zinc fingers, and the 306-kDa ATBF1-B, lacking a 920-amino acid N-terminal region of ATBF1-A which contains 5 zinc fingers. In vitro, ATBF1-A was expressed in proliferating C2C12 myoblasts, but its expression levels decreased upon induction of myogenic differentiation in low serum medium. Forced expression of ATBF1-A in C2C12 cells resulted in repression of MyoD and myogenin expression and elevation of Id3 and cyclin D1 expression, leading to inhibition of myogenic differentiation in low serum. In contrast, transfection of C2C12 cells with the ATBF1-B isoform led to an acceleration of myogenic differentiation, as indicated by an earlier onset of myosin heavy chain expression and formation of a higher percentage of multinucleated myotubes. The fourth homeodomain of ATBF1-A bound to an AT-rich element adjacent to the E1 E-box of the muscle regulatory factor 4 promoter mediating transcriptional repression. The ATBF1-A-specific N-terminal region possesses general transcription repressor activity. These results suggest that ATBF1-A plays a role in the maintenance of the undifferentiated myoblast state, and its down-regulation is a prerequisite to initiate terminal differentiation of C2C12 cells.

Animals↗

PubMed2001

Glycoxidation and lipid peroxidation of low-density lipoprotein can synergistically enhance atherogenesis.

OBJECTIVE: The purpose of this study was to clarify the role of glycoxidation and lipid peroxidation of low-density lipoprotein (LDL) in atherogenesis. METHODS AND RESULTS: We examined the formation of N(epsilon)-(carboxymethyl) lysine (CML), a glycoxidation product, and malondialdehyde (MDA), a lipid peroxidation product, in vitro and their co-localization in human atherosclerotic lesions. Immunochemical analysis revealed that CML was formed in a time-dependent manner by human LDL incubated with copper ions and glucose, i.e. an in vitro model of glycoxidation of LDL. When LDL was exposed to copper ions alone, a small amount of CML was formed, however this was significantly less in oxidized LDL than glycoxidative LDL. In contrast, MDA formation was observed in both oxidation and glycoxidation of LDL, but not in glycation of LDL. Hexitol-lysine (HL), an Amadori product, was formed by both glycation and glycoxidation of LDL, but not by oxidation of LDL. Immunohistochemical analysis showed that CML and MDA accumulated mainly in macrophage/foam cells, while pyrraline, a non-oxidative product of glycation, and apolipoprotein B were localized in the extracellular matrix in atherosclerotic lesions. Atheromas were positive for CML and MDA, but negative for pyrraline. Macrophage/foam cells in atherosclerotic lesions exhibited co-localization of macrophage scavenger receptor-A with CML and MDA, but not with pyrraline. CONCLUSION: Our results suggest that glycoxidation and lipid peroxidation of LDL synergistically promote the development of atherosclerotic lesions through interaction with macrophage scavenger receptor-A.

Adult↗

PubMed2001

Alternative splicing of Rh blood group polypeptide mRNA produces a novel transcript containing a short nucleotide insertion on human erythroleukemia K562 cells.

A novel isoform of the human Rh blood group polypeptide cDNA was isolated from human erythroleukemic K562 cells. This isoform was produced by deletion of the sequences derived from exons 2 and 3 of the RHCE gene and insertion of 44-bp into the resulting junction between exon 1 and 4 derived sequence. The deduced amino acid sequence revealed that the 44-bp insertion sequence contains an in-frame stop codon that causes premature chain termination. A sequence homology search using GenBank showed that the inserted sequence was derived from the intron between exons 1 and 2 of the RHCE gene. Moreover, analysis of the region surrounding the inserted sequence indicated that the insert was a cryptic exon flanked by consensus donor and acceptor splice sequences. This novel transcript was most likely produced by alternative splicing.

Alternative Splicing↗

PubMed2001

Pneumococcal arthritis affects performance status in patients with chronic GVHD of the skin following allogeneic bone marrow transplantation.

We encountered 2 patients with pneumococcal arthritis following bone marrow transplantation (BMT). Both patients received grafts from unrelated human lymphocyte antigen (HLA)-matched donors and had suffered from chronic graft-versus-host disease (GVHD). One, a 10-year-old boy, suffered from Epstein-Barr virus-related lymphoproliferative disease (EB-LPD) and received oral 6-mercaptopurine and methotrexate to manage lymphadenopathy. Twenty-four months after BMT and 7 months after the onset of EB-LPD, pneumococcal arthritis occurred in both knee joints. The other patient, a 10-year-old girl, received multiagent immunosuppressive therapy for her chronic GVHD. At 51 months following BMT, pneumococcal arthritis occurred in her left knee joint. Chronic GVHD of the skin delayed the recovery from the arthritis in both patients. This complication is quite rare but can be very serious, in regard to the patient's performance status following BMT. Although vaccination against pneumococcus or preventive antibiotics should be administered to high-risk patients, early diagnosis and treatment may be the best strategy for pneumococcal arthritis.

Anti-Bacterial Agents↗

PubMed2001

Nucleotide sequence of BamHI family satellite DNA and its unit length polymorphism in bluegill sunfish Lepomis macrochirus.

We have isolated and sequenced a member of tandem repetitive DNA containing BamHI site (BamHI family satellite DNA) from bluegill sunfish Lepomis macrochirus. PCR amplification with specific primers was performed to define the size of unit length repeat of the BamHI family satellite DNA, revealing that there were two distinct size of DNA fragments (0.9 kb and 1.3 kb) in the PCR products. The longer fragment (1.3 kb) consisted of internal sub-duplication of shorter fragment (0.9 kb). We have compared the size of PCR products among four fish populations, and found that both fragments co-existed in one population whereas the longer fragment was dominant in other three populations. The results may reflect ongoing homogenization of satellite DNA type over a short evolutionary time scale.

Animals↗