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Akira Shimizu

Publications and source records attributed to Akira Shimizu.

At least 37 records · Page 2Linked to original sources
PubMed2006

Quantification of caveolin isoforms using quantitative real-time RT-PCR, and analysis of promoter CpG methylation of caveolin-1alpha in human T cell leukemia cell lines.

Caveolin-1, an essential structural component of caveolae, functions as a negative regulator for signal transduction and has been suggested to be a candidate tumor suppressor. Lack of caveolin-1 expression has been implicated in the pathogenesis of oncogenic cell transformation and tumorigenesis in many cancers. On the other hand, over-expression has also been associated with tumor progression and metastasis in prostate cancers. Hence, alteration of caveolin-1 expression has been proposed as a clinical marker for diagnosis and prognosis in various cancers. For precise analyses of the caveolin expression in human T cell leukemia cell lines, we measured the mRNA levels of caveolin isoforms, caveolin-1alpha, -1beta, -2, and -3 with real-time RT-PCR using external standards for each isoform. In the panel of human T cell leukemia cell lines tested, four cell lines expressed caveolin-1alpha, -1beta and -2, but not -3, which was consistent with the protein levels. The expression profiles in most cell lines are caveolin-1alpha > caveolin-1beta > caveolin-2. Two cell lines did not express either of the caveolin mRNAs. Methylation analyses for the CpG sites in the promoter region of a positive and a negative cell line did not show a clear correlation with the expression status, suggesting that mechanisms other than CpG methylation are involved in the regulation of caveolin-1alpha expression in human T cell leukemia cell lines.

Caveolin 1↗
PubMed2006

[A combination study of S-1 and docetaxel in patients with head and neck cancer].

We determined the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and efficacy of drug sequence on toxicities of the combination of S-1 and docetaxel for head and neck cancers. S-1 was administered at the full dose of 80 mg/m2 for two weeks and docetaxel on day 1 according to the following dose escalation schedule: level 1: 40 mg/m2, level 2: 50 mg/m2, and level 3: 60 mg/m2. DLT was observed in two cases of level 3. Although grade 3 leukopenia was observed in level 3, all of the toxicities were not severe. Recommended doses for the next phase evaluation were determined to be 80 mg/m2 of S-1 and 50 mg/m2 of docetaxel. Oral S-1 combination with docetaxel is a feasible and promising combination regimen that is appropriate for an outpatient setting.

Administration, Oral↗
PubMed2006

[Analysis of variant and modified structures of proteins by mass spectrometry--application for clinical laboratory test].

We have successfully applied soft ionization MS for the analysis of proteins in blood and tissues. This article is a summary of a lecture presented on March 8, 2006 in the Hall of Osaka Medical College at the time of the author's retirement from Osaka Medical College. The article addresses the detection and characterization of hemoglobin (Hb) variants, an improved reference method for HbAlc measurement, identification of variants of transthyretin (TTR) and Cu/Zn-superoxide dismutase (SOD-1) and the diagnostic application of the signals of modified forms of TTR. During the process of TTR analysis, we found unique isoforms of TTR, which showed changes of the cysteine (10th from amino terminal) residue to glycine, dehydroalanine, and S-sulfocysteine residues. Without the addition of sulfuric acid, the S-sulfonated adduct was generated, namely, sulfur was generated from the peptide or protein itself via dimer formation. These experiments suggest that transformation starts from beta-elimination of disulfide linkage to dehydroalanine and S-thiocysteine. Dehydroalanine reacts easily with H2O, generating serine, which changes to glycine. S-thiocysteine is oxidized easily to S-sulfocysteine. Such modified structures were never seen in SOD-1 and Hb in our extensive analyses by MS, although these molecules have free cysteine residue. Susceptibility to beta-elimination may depend on adjacent amino acids in the stereochemical structure of the protein. Basic amino acids located near cysteine 10, lysine residues at 9 and/or 15, may promote the reaction. As dehydroalanine in protein reacts strongly with other amino acids either in the molecule or between molecules, the reaction may generate cross-linking covalently or noncovalently, causing amyloidosis. Dehydroalanine reacts with cysteine, forming a thiazolidine ring, followed by cleavage of the peptide-bond at the N-terminal side of dehydroalanine. This type of non-enzymatic cleavage may occur in amyloidogenic precursor protein before fiber formation or in amyloid fibers.

Blood Proteins↗
PubMed2005

Enhanced anti-fibrotic activity of plasmid DNA expressing small interference RNA for TGF-beta type II receptor for a mouse model of obstructive nephropathy by cationized gelatin prepared from different amine compounds.

The objective of this study is to increase the transfection efficiency of a plasmid DNA expressing small interference RNA (siRNA) for transforming growth factor-beta receptor (TGF-betaR) by various cationized gelatins of non-viral carrier and evaluate the anti-fibrotic effect with a mouse model of unilateral ureteral obstruction (UUO). Ethylenediamine, putrescine, spermidine or spermine was chemically introduced to the carboxyl groups of gelatin for the cationization. The plasmid DNA of TGF-betaR siRNA expression vector with or without complexation of each cationized gelatin was injected to the left kidney of mice via the ureter to prevent the progression of renal fibrosis of UUO mice. Irrespective of the type of cationized gelatin, the injection of plasmid DNA-cationized gelatin complex significantly decreased the renal level of TGF-betaR over-expression and the collagen content of mice kidney, in marked contrast to free plasmid DNA injection. It is concluded that retrograde injection of TGF-betaR siRNA expression vector plasmid DNA complexed with the cationized gelatin is available to suppress the progression of renal interstitial fibrosis.

Amines↗
PubMed2005

Vascularized thymic lobe transplantation in a pig-to-baboon model: a novel strategy for xenogeneic tolerance induction and T-cell reconstitution.

BACKGROUND: This laboratory has previously demonstrated the induction of allogeneic tolerance by vascularized thymic lobe (VTL) transplantation in miniature swine. We report here our initial attempt to induce tolerance by VTL transplantation in the clinically relevant, discordant, pig-to-baboon model of xenotransplantation. METHODS: Six baboons received xenografts of hDAF VTLs. Four of these baboons also received omental thymic tissue implants. All recipients were treated with an immunosuppressive conditioning regimen that included thymectomy, splenectomy, extracorporeal immunoadsorption of anti-alpha Gal antibodies, and T-cell depletion. Two control baboons received sham operations, of which one also received 5x10 hDAF porcine thymocytes/kg intravenously. RESULTS: Transplanted VTL grafts supported early thymopoiesis of recipient-type immature thymocytes, and facilitated engraftment of nonvascularized thymic omental implants. Recipients of the VTL grafts demonstrated donor-specific unresponsiveness in MLR assays, development of peripheral CD45RAhigh/CD4 double positive (DP) cells, and positive cytokeratin staining of thymic stroma in the grafts for 2 months following xenotransplantation. The control baboons did not show these markers of thymic reconstitution. The eventual return of Gal natural antibodies led to the destruction of graft epithelial cells and the rejection of all VTL grafts by 3 months posttransplantation. CONCLUSIONS: VTL transplantation from hDAF swine to baboons induced early thymopoiesis in the recipients and donor-specific cellular unresponsiveness in vitro. When coupled with additional strategies aimed at silencing humoral rejection, VTL transplantation may significantly prolong xenograft survival and result in long-term tolerance.

Animals↗
PubMed2005

alpha1,3-Galactosyltransferase gene-knockout pig heart transplantation in baboons with survival approaching 6 months.

BACKGROUND: The recent generation of alpha1,3-galactosyltransferase gene-knockout (GalT-KO) pigs has allowed investigation of the survival of GalT-KO pig organs in nonhuman primates. METHODS: Heterotopic heart transplantation from GalT-KO pigs was carried out in baboons (n=8) using a human antihuman CD154 monoclonal antibody-based immunosuppressive regimen. RESULTS: In six of the eight cases, graft survival extended to between approximately 2 and 6 months. All grafts developed thrombotic microangiopathy (TM). In particular, the clinical course of one baboon in which the graft functioned for 179 days is summarized. This baboon received aspirin (40 mg on alternate days) from day 4 in addition to heparin, which may have been a factor in the delay of onset and progression of TM and in prolonged graft survival. Maintenance therapy with anti-CD154 mAb, mycophenolate mofetil, and methylprednisolone was associated with persistently low numbers of CD3CD4 and CD3CD8 cells. Despite persisting depletion of these cells, no infectious complications occurred. CONCLUSIONS: It remains to be established whether TM is related to a very low level of natural preformed or T-cell-induced antibody deposition on the graft, inducing endothelial activation and injury, or to molecular incompatibilities in the coagulation mechanisms between pig and baboon, or to both. However, function of a pig organ in a baboon for a period approaching six months, which has not been reported previously, lends encouragement that the barriers to xenotransplantation will eventually be overcome.

Animals↗
PubMed2005

Detection of macroscopic entanglement by correlation of local observables.

We propose a correlation of local observables on many sites in macroscopic quantum systems. By measuring the correlation one can detect, if any, superposition of macroscopically distinct states, which we call macroscopic entanglement, in arbitrary quantum states that are (effectively) homogeneous. Using this property, we also propose an index of macroscopic entanglement.

Journal Article↗
PubMed2005

Thrombotic microangiopathic glomerulopathy in human decay accelerating factor-transgenic swine-to-baboon kidney xenografts.

Models of pig-to-baboon xenografting were examined to identify the mechanisms and pathologic characteristics of acute humoral xenograft rejection (AHXR). Thymus and kidney (composite thymokidney) from human decay accelerating factor-transgenic swine were transplanted into baboons (n = 16) that were treated with an immunosuppressive regimen that included extracorporeal immunoadsorption of anti-alphaGal antibody and inhibition of complement activation. Morphologic and immunohistochemical studies were performed on protocol biopsies and graftectomy samples. All renal xenografts avoided hyperacute rejection. However, graft rejection coincided with the increase of anti-alphaGal antibody in the recipient's circulation. The 16 xenografts studied were divided into two groups dependent on the rapid return (group 1) or gradual return (group 2) of anti-alphaGal antibody after immunoadsorption. In group 1 (n = 6), grafts were rejected to day 27 with development of typical AHXR, characterized by marked interstitial hemorrhage and thrombotic microangiopathy in the renal vasculature. In group 2 (n = 10), grafts also developed thrombotic microangiopathy affecting mainly the glomeruli by day 30 but also showed minimal evidence of interstitial injury and hemorrhage. In the injured glomeruli, IgM and C4d deposition, subsequent endothelial cell death and activation with upregulation of von Willebrand factor and tissue factor, and a decrease of CD39 expression developed with the formation of fibrin-platelet multiple microthrombi. In this model, the kidney xenografts, from human decay accelerating factor-transgenic swine, in baboons undergo AHXR. In slowly evolving AHXR, graft loss is associated with the development of thrombotic microangiopathic glomerulopathy. Also, anti-alphaGal IgM deposition and subsequent complement activation play an important role in the mechanism of glomerular endothelial injury and activation and the formation of multiple microthrombi.

Acute Disease↗
PubMed2005

Delivery of plasmid DNA expressing small interference RNA for TGF-beta type II receptor by cationized gelatin to prevent interstitial renal fibrosis.

Renal interstitial fibrosis is the common pathway of chronic renal disease, while it causes end-stage renal failure. Transforming growth factor-beta (TGF-beta) is well recognized to be one of the primary mediators to induce accumulation of extracellular matrix (ECM) in the fibrotic area. Therefore, it is expected that local suppression of TGF-beta receptor (TGF-betaR) is one of the crucial strategies for anti-fibrotic therapy. The objective of this study is to investigate feasibility of small interference RNA (siRNA) for TGF-betaR in the selective degradation of TGF-betaR mRNAs, resulting in fibrotic inhibition. A plasmid DNA of TGF-betaR siRNA expression vector with or without complexation of a cationized gelatin was injected to the left kidney of mice via the ureter. Unilateral ureteral obstruction (UUO) was performed for the injected mice to evaluate the anti-fibrotic effect. The injection of plasmid DNA-cationized gelatin complex significantly decreased the level of TGF-betaR and alpha-smooth muscle actin (alpha-SMA) over-expression, the collagen content of mice kidney, and the fibrotic area of renal cortex, in contrast to free plasmid DNA injection. It is concluded that retrograde injection of TGF-betaR siRNA expression vector plasmid DNA complexed with the cationized gelatin is available to suppress progression of renal interstitial fibrosis.

Animals↗
PubMed2005

Diffusion dynamics of the Li+ ion on a model surface of amorphous carbon: a direct molecular orbital dynamics study.

Diffusion processes of the Li+ ion on a model surface of amorphous carbon (Li+C96H24 system) have been investigated by means of the direct molecular orbital (MO) dynamics method at the semiempirical AM1 level. The total energy and energy gradient on the full-dimensional AM1 potential energy surface were calculated at each time step in the dynamics calculation. The optimized structure, where Li+ is located in the center of the cluster, was used as the initial structure at time zero. The dynamics calculation was carried out in the temperature range 100-1000 K. The calculations showed that the Li+ ion vibrates around the equilibrium point below 200 K, while the Li+ ion moves on the surface above 250 K. At intermediate temperatures (300 K < T < 400 K), the ion moves on the surface and falls in the edge regions of the cluster. At higher temperatures (600 K < T), the Li+ ion transfers freely on the surface and edge regions. The diffusion pathway of the Li+ ion was discussed on the basis of theoretical results.

Journal Article↗
PubMed2005

Renal allograft rejection is prevented by adoptive transfer of anergic T cells in nonhuman primates.

Anergic T cells generated ex vivo are reported to have immunosuppressive effects in vitro and in vivo. Here, we tested this concept in nonhuman primates. Alloreactive T cells were rendered anergic ex vivo by coculture with donor alloantigen in the presence of anti-CD80/CD86 mAbs before adoptive transfer via renal allograft to rhesus monkey recipients. The recipients were briefly treated with cyclophosphamide and cyclosporine A during the preparation of the anergic cells. Thirteen days after renal transplantation, the anergic T cells were transferred to the recipient, after which no further immunosuppressive agents were administered. Rejection-free survival was prolonged in all treated recipients, and 3 of 6 animals survived long term (410-880 days at study's end). In the long-surviving recipients, proliferative responses against alloantigen were inhibited in a donor-specific manner, and donor-type, but not third-party, skin allografts were also accepted, which demonstrated that antigen-specific tolerance had been induced. We conclude that anergic T cells generated ex vivo by blocking CD28/B7 costimulation can suppress renal allograft rejection after adoptive transfer in nonhuman primates. This strategy may be applicable to the design of safe clinical trials in humans.

Adoptive Transfer↗
PubMed2005

Novel serpinopathy in rat kidney and pancreas induced by overexpression of megsin.

The intracellular polymerization of abnormal serine protease inhibitors (serpins) results in liver or neuronal cell abnormalities recently identified as "serpinopathies." It was demonstrated in transgenic rats that overexpression of megsin, a recently discovered serpin located in the kidney, produces renal and pancreatic lesions characteristic of serpinopathies. Megsin expression is elevated in a variety of organs, including kidney and pancreas. Periodic acid-Schiff-positive, diastase-resistant intracellular inclusions develop only in the kidney and the pancreas. They correspond to electron-dense deposits, shown to contain megsin by immunohistochemistry and immunoelectron microscopy. In the kidney, inclusions are located mainly in the endoplasmic reticulum of glomerular epithelial, distal, and collecting duct cells, and are associated with massive proteinuria and an impaired renal function. In the pancreas, similar inclusions are found in the exocrine and Langerhans islet cells, where islet beta cells are reduced as a result of apoptosis. They are associated with diabetes with low insulin levels. The animals have an impaired growth and die within 10 wk. Rats that overexpress a mutant megsin, characterized by a deficient conformational transition activity, do not develop the serpinopathy, suggesting that some conformational flexibility of the serpin is required for the development of serpinopathy. This model of serpinopathy is the first to involve the kidney and the pancreas.

Animals↗
PubMed2005

CpG inhibits IgE class switch recombination through suppression of NF kappa B activity, but not through Id2 or Bcl6.

The CpG motif in DNA plays a critical role in immunity via modulating the Th1/Th2 balance. In B cells, CpG-containing oligodeoxynucleotides (CpG ODNs) inhibit IL-4-mediated class switch recombination (CSR) to IgG1 and IgE through inhibition of the germline transcription (GLT) of these isotypes. However, the molecular mechanism of this inhibitory effect remains elusive. We showed here that Id2 and Bcl6, both of which inhibit IgE GLT and CSR, are not involved in this inhibitory pathway. We demonstrated that there is reduced activity of NF kappa B binding to the IgE promoter and a reduction of Irf4 protein in CpG ODN-treated B cells. These data indicate the critical role of NF kappa B and Irf4 in the regulation of IgE CSR through actions downstream of CpG signaling.

Animals↗
PubMed2005

Multiple SNPs in intron 7 of thyrotropin receptor are associated with Graves' disease.

Our previous studies using microsatellite markers near or in the TSH receptor (TSHR) gene revealed significant association between autoimmune thyroid disease (AITD) in Japanese patients and TSHR microsatellite alleles. In the present study, we performed a case-control analysis of AITD using single-nucleotide polymorphisms (SNPs) spaced 3-50 kb apart spanning the TSHR gene. We observed significant associations between AITD/Graves' disease (GD)/Hashimoto's thyroiditis and multiple SNPs. Specifically, the SNP JST022302 and several adjacent SNPs in intron 7 of the TSHR gene were significantly associated with GD (P = 0.039-0.0004) but not Hashimoto's thyroiditis. Furthermore, we identified three haplotype blocks around intron 7 by linkage disequilibrium analysis. A single SNP haplotype [AATG(CT)6(TT)AG] in the haplotype block including JST022302 showed significant association with GD in haplotype case-control analysis (P = 0.0058). These findings suggest that alleles of intron 7 of the TSHR gene contribute to GD susceptibility.

Case-Control Studies↗
PubMed2005

Cell shrinkage evoked by Ca2+-free solution in rat alveolar type II cells: Ca2+ regulation of Na+-H+ exchange.

The effects of intracellular Ca2+ concentration, [Ca2+]i, on the volume of rat alveolar type II cells (AT-II cells) were examined. Perfusion with a Ca2+-free solution induced shrinkage of the AT-II cell volume in the absence or presence of amiloride (1 microm, an inhibitor of Na+ channels); however, it did not in the presence of 5-(N-methyl-N-isobutyl)-amiloride (MIA, an inhibitor of Na+-H+ exchange). MIA decreased the volume of AT-II cells. Inhibitors of Cl(-)-HCO3- exchange, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) also decreased the volume of AT-II cells. This indicates that the cell shrinkage induced by a Ca2+-free solution is caused by a decrease in NaCl influx via Na+-H+ exchange and Cl(-)-HCO3- exchange. Addition of ionomycin (1 microm), in contrast, induced cell swelling when AT-II cells were pretreated with quinine and amiloride. This swelling of the AT-II cells is not detected in the presence of MIA. Intracellular pH (pHi) measurements demonstrated that the Ca2+-free solution or MIA decreases pHi, and that ionomycin increases it. Ionomycin stimulated the pHi recovery after an acid loading (NH4+ pulse method), which was not noted in MIA-treated AT-II cells. Ionomycin increased [Ca2+]i in fura-2-loaded AT-II cells. In conclusion, the Na+-H+ exchange activities of AT-II cells, which maintain the volume and pHi, are regulated by [Ca2+]i.

Animals↗
PubMed2005

Bowen's disease involving the urethra.

Bowen's disease developing on mucous or mucocutaneous regions is clinically called erythroplasia of Queyrat. We report herein a 56-year-old male with Bowen's disease extending from the penis shaft to the glans penis, and urethral meatus. Physical examination revealed bright red velvety plaques on the prepuce and glans penis and an irregularly pigmented scaly lesion on the dorsum of his penis shaft. Histopathological findings of both lesions were compatible with those of Bowen's disease, supporting the concept that erythroplasia of Queyrat and Bowen's disease should be regarded as one clinicopathologic entity. A partial penectomy was finally performed, because tumor cells were pathologically observed in the mucous epithelium of the urethra. Although several therapeutic modalities exist for Bowen's disease on the external genitalia, treatment options are limited when Bowen's disease extends to the urethral meatus. We discussed the recent therapeutic modalities in genital Bowen's disease.

Biopsy, Needle↗
PubMed2005

Cholesterol crystal embolization: skin manifestation, gastrointestinal and central nervous symptom treated with corticosteroid.

Cholesterol crystal embolization (CCE) is characterized by tissue ischemia secondary to occlusion of small arteries. It may occur spontaneously but more often follows radiological interventional procedures or vascular surgery. This systemic disease affects multiple organs, including skin, kidney, brain, eye, and gastrointestinal tract. We reported a Japanese male CCE patient with cutaneous manifestations of livedo reticularis, diarrhea, clouding of consciousness, and acute renal failure. Histopathological examination demonstrated multiple biconvex clefts in a vessel of the subcutis. Corticosteroid administration improved his consciousness, diarrhea and skin lesions. Awareness of the skin manifestations of CCE is essential for dermatologists to make an early diagnosis and prescribe appropriate treatment.

Administration, Oral↗