Biomedical subjects

S Miyatake

Publications and source records attributed to S Miyatake.

At least 37 records · Page 2Linked to original sources

PubMed1999

Chromosomal mapping of two RBP-J-related genes: Kyo-T and RBP-L.

We have recently isolated two genes encoding proteins which have either homology or affinity to RBP-J, a transcription factor involved in Notch signaling. Kyo-T interacts with RBP-J and possibly regulates the function of RBP-J. RBP-L has a highly homologous region with RBP-J but the function of RBP-L is unknown. Fluorescence in situ hybridization analysis of human metaphase chromosomes localized Kyo-T and RBP-L to Xq26 and 20q12-13.1, respectively.

Base Sequence↗

PubMed1999

Radioimmunotherapy of human glioma xenografts in nude mice by indium-111 labelled internalising monoclonal antibody.

The potential of 111Indium (111In)-labelled internalising anti-integrin alpha 3 antibody GA17 in the radioimmunotherapy of human glioblastoma xenografts in nude mice was investigated. A radioisotope retention assay showed a rapid release of radioiodine from the glioblastoma cells after the binding of 125I-GA17, whilst 111In-GA17 was retained in the cells for a longer time period. The glioblastoma xenografts showed a high and prolonged uptake of 111In-GA17, and tumour uptake of 125I-GA17 was lower and decreased with time. In the mice which received two injections of 18.5 MBq of 111In-GA17, the growth of the subcutaneous tumour was significantly suppressed compared with the untreated group and mice injected with an 111In-labelled control antibody. These results indicate that GA17 was internalized into the glioblastoma cells and that 111In was retained within the cancer cells. The injection of a high-dose of 111In-GA17 can suppress the growth of tumour xenografts in nude mice.

Animals↗

PubMed1999

Adenovirus-mediated gene transfer of a truncated form of fibroblast growth factor receptor inhibits growth of glioma cells both in vitro and in vivo.

Basic fibroblast growth factor (FGF-2) and high affinity FGF receptor (FGFR) have been detected in the nucleus as well as the cytoplasm of many human gliomas, and are known to stimulate cellular proliferation and angiogenesis in the tumors. To investigate the effects of inactivation of FGFR on the growth of malignant gliomas, we constructed a replication-deficient recombinant adenovirus vector encoding a truncated form of chicken FGFR1 (AxCA delta FR). AxCA delta FR-infected cells were confirmed to express truncated FGFR protein by immunoblotting and FGF-2-dependent clonogenicity of NIH3T3 cells was suppressed by infection with this virus vector. Then human malignant glioma cell lines U-251MG and T98G, both of which have been reported to express FGF-2 and FGFR, were infected with AxCA delta FR. These infected cells showed nuclear as well as cytoplasmic expression of a truncated FGFR protein. Proliferation rate and the ability to form colonies in soft agar of the cells infected with this virus vector were significantly suppressed compared with those of uninfected and lacZ-expressing adenovirus-infected cells. Moreover, intratumoral injection of AxCA delta FR significantly suppressed the subcutaneous tumor growth of the glioma cells in nude mice. We concluded that inactivation of the cytoplasmic and nuclear FGFR using this truncated FGFR-expressing adenovirus vector can inhibit the growth of malignant gliomas both in vitro and in vivo.

3T3 Cells↗

PubMed1999

Mutant herpes simplex virus-mediated suppression of retinoblastoma.

PURPOSE: To test the ability of a mutant herpes simplex virus (HSV) hrR3 to inhibit growth of Y79 human retinoblastoma in vitro and in vivo. METHODS: Cultured Y79 cells were infected with multiplicities of infection (MOI) ranging from 0.004 to 0.1 of hrR3. Surviving cells were counted using trypan blue dye exclusion. Using X-gal staining, expression of the lacZ gene was examined in vitro on day 3 postinfection to evaluate viral replication. Nude mice harboring Y79 tumors subcutaneously received an intraneoplasmic injection of 5 x 10(7) plaque-forming units of hrR3. The tumor sizes were measured weekly. Expression of the lacZ gene was also examined on one week postinfection. RESULTS: There are 31% and 13% cells surviving in cultured Y79 cells infected by hrR3 at an MOI of 0.1 on days 3 and 5 postinfection respectively compared to those of mock-infected cells. Also more than 70% of Y79 cells were stained with X-gal at an MOI of 0.1 which demonstrated active viral replication in vitro. Virus-treated subcutaneous tumors were smaller than control tumors (p<<0.05, Student's t-test) on days 14, 21, and 28 postinfection. Positive X-gal staining was also observed in the tumor nodule which was challenged with this viral vector. CONCLUSIONS: We have demonstrated that hrR3 is capable of inhibiting Y79 tumor growth both in cell culture and in nude mice. These data suggest that gene therapy using this mutant HSV vector can be a new supplementary therapeutic modality for retinoblastoma.

Animals↗

PubMed1999

Comparison of pharmacokinetics of NS-105, a novel agent for cerebrovascular disease, in elderly and young subjects.

Pharmacokinetics of NS-105, a novel agent for cerebrovascular disease, in elderly subjects were compared with those in younger subjects. Fourteen healthy male volunteers (7 elderly subjects aged 68-79 years and 7 young subjects aged 20-32 years) were included in the study. In a parallel group design, a tablet containing 100 mg NS-105 was administered orally after breakfast. One young subject was excluded from the pharmacokinetic analyses owing to an insufficient urine collection. The maximum plasma concentration (Cmax) was higher in the elderly (3.06 +/- 0.69 vs. 2.13 +/- 0.34 micrograms/ml, the elderly vs. the young, mean +/- SD, p = 0.0117) and area under the plasma concentration curve (AUC) was also higher in the elderly (24.6 +/- 4.4 vs. 14.4 +/- 3.1 micrograms.hr/ml, p = 0.0006). There is a tendency that time to reach Cmax was longer in the elderly (2.1 +/- 1.1 vs. 1.3 +/- 0.5 hr, p = 0.1199), and a tendency of prolongation of elimination half-life. Urinary recovery of NS-105 was less in the elderly up to 8 h after administration, while total recovery of the dose was not different in the two groups. Total clearance was reduced in the elderly (0.076 +/- 0.013 vs. 0.121 +/- 0.025l/kg/hr, p = 0.0013) and the decrease seemed to be mainly due to a decrement in renal clearance of the drug in the elderly. A significant correlation was found between renal clearance of NS-105 and creatinine clearance of each subject (r = 0.583, p = 0.0364). These observations indicate that the plasma concentration of NS-105 will increase in elderly subjects mainly due to a decrement in renal clearance of the drug. Careful observation is needed when prescribing the drug to an elderly patient.

Adult↗

PubMed1999

Adenovirally expressed basic fibroblast growth factor rescues photoreceptor cells in RCS rats.

PURPOSE: To evaluate the abilities of recombinant adenovirus carrying the basic fibroblast growth factor (bFGF) gene to (1) produce bFGF protein in vitro and (2) rescue retinal photoreceptors in Royal College of Surgeons (RCS) rats in vivo. METHODS: Cultured human retinal pigment epithelial cells were infected with one of the following two replication-deficient adenoviral vectors that drive inserted genes by beta-actin promoter with cytomegalovirus enhancer: AxCAJSbFGF, which expresses the human bFGF gene, and AxCAlacZ, carrying the cDNA of bacterial beta-galactosidase as a viral control. These viruses and recombinant bFGF protein were also injected into the subretinal space of RCS rats at the age of 21 days. The production of bFGF was evaluated by an immunohistochemical method in vitro and in vivo. The secretion of bFGF produced in vitro was quantified by an enzyme-linked immunosorbent assay. The thickness of the outer nuclear layer (ONL) as a marker of photoreceptor cell rescue was estimated at 2, 28, and 56 days after the injections. RESULTS: AxCAJSbFGF produced human bFGF protein effectively both in vitro and in vivo. The semiquantitative analysis of ONL thickness revealed a significant protective effect of AxCAJSbFGF and the recombinant bFGF protein injection up to 56 days after injection. CONCLUSIONS: These results demonstrate that a recombinant adenoviral vector can achieve the transfer of bFGF gene in vitro and have a protective effect for photoreceptor cells in vivo. Gene therapy with a bFGF-expressing recombinant adenoviral vector may provide a new strategy with which to target retinal degenerative diseases.

Adenoviridae↗

PubMed1998

Purification, cDNA cloning and expression of human NG,NG-dimethylarginine dimethylaminohydrolase.

cDNA encoding N(G),N(G)-dimethylarginine dimethylaminohydrolase from rat kidney had been cloned [Kimoto, M., Sasakawa, T., Tsuji, H., Miyatake, S., Oka, T., Nio, N. & Ogawa, T. (1997) Biochim. Biophys. Acta 1337, 6-10]. The enzyme hydrolyzes N(G),N(G)-dimethyl-L-arginine and N(G)-monomethyl-L-arginine, which are known as endogenous inhibitors for the nitric oxide-generating system. In the present study, human N(G),N(G)-dimethylarginine dimethylaminohydrolase has been purified to homogeneity from liver and characterized. The cDNA clone encoding human N(G),N(G)-dimethylarginine dimethylaminohydrolase was isolated from a human kidney lambda gt10 library using a probe prepared from a plasmid containing the entire coding region of rat N(G),N(G)-dimethylarginine dimethylaminohydrolase. Its open reading frame encoded a protein of 285 amino acids with a molecular mass of 31,121 Da. The deduced amino acid sequence exhibits 93% identity with that of rat. The cDNA was expressed as a fusion protein in Escherichia coli and the recombinant protein exhibited enzyme activity which is the same as that of natural enzyme.

Amidohydrolases↗

PubMed1998

Src family tyrosine kinases associate with and phosphorylate CTLA-4 (CD152).

CTLA-4 (CD152) transduces inhibitory signals for T cell activation. Phosphorylation and dephosphorylation of tyrosine residue (Y)-165 in the cytoplasmic region of CTLA-4 play an important role in the signal transduction and in the cell surface. While signaling molecules such as SHP-2 and the p85 subunit of PI3 kinase associate with this tyrosine residue through SH2 domains upon phosphorylation, the adapter complex AP-2 interacts with the same tyrosine when dephosphorylated, leading to clathrin-mediated endocytosis of CTLA-4. We searched for the tyrosine kinase responsible for the phosphorylation of CTLA-4. Src family tyrosine kinases Fyn, Lyn, and Lck associate with CTLA-4 and phosphorylate both Y-165 and Y-182 that are mainly responsible for interaction with Fyn through its SH2 domain. SHP-2 associates with CTLA-4, in a Fyn-dependent manner. Our observations show that src family tyrosine kinases associate with and phosphorylate CTLA-4 and thereby have an important role in the signal transduction and the endocytosis of CTLA-4.

Abatacept↗

PubMed1998

Isolation and characterization of novel endogenous digitalis-like factors in the ovary of the giant toad, Bufo marinus.

We have previously described the structures of four novel unconjugated bufadienolides in the ovary of the toad, Bufo marinus. In this study, we report the separation and characterization of three novel bufadienolide conjugates. These compounds were purified by HPLC, and their structures were determined to be 11alpha, 19-dihydroxytelocinobufagin-3-(12-hydroxydodecanoic acid) ester, 11alpha,19-dihydroxytelocinobufagin-3-(14-hydroxy-7-tetra decenoic acid) ester, and 11alpha, 19-dihydroxytelocinobufagin-3-(14-hydroxytetradecanoic acid) ester on the basis of NMR and MS data. Numerous dicarboxylic acid esters of bufadienolides have previously been described, but the three bufadienolide conjugates described in this report differ from previously described esters in that they contain hydroxylated monocarboxylic acids. The function of these three conjugates is not known but they are, like bufotoxins, potent inhibitors of Na+, K+-ATPase and may play a developmental role in the differentiation of toad oocytes.

Animals↗

PubMed1998

Th2-specific DNase I-hypersensitive sites in the murine IL-13 and IL-4 intergenic region.

IL-4 and IL-13 are cytokines preferentially produced by Th2 cells, and their genes are located in close proximity on human chromosome 5 and mouse chromosome 11. To identify potential regulatory elements that confer Th2-specific expression of IL-4 and IL-13 genes, we constructed a physical map of the IL-13/IL-4 locus and conducted DNase I-hypersensitive (DH) site analysis using Th clones and in vitro-differentiated effector Th cells obtained from TCR transgenic mice. Three DH sites, HSS1, HSS2 and HSS3, were identified within the intergenic region between IL-13 and IL-4 genes. HSS3 was observed both in Th1 and Th2 cells as well as CD4+ naive T cells, while HSS1 and HSS2 were detected exclusively in Th2 cells. The correlation between differentiation into Th2 subtype and the appearance of HSS1 and HSS2 suggests that these regions may play a role in subtype-specific expression of the IL-13/IL-4 locus.

3' Untranslated Regions↗

PubMed1997

A novel acyl-CoA thioesterase enhances its enzymatic activity by direct binding with HIV Nef.

In addition to playing a crucial role in the pathogenesis of AIDS, HIV nef induces down-regulation of CD4 expression and TCR signaling and also regulates the sorting pathway in host T cells. To elucidate the Nef function in HIV progression, we searched for a cellular component which interacts with Nef. A human cDNA encoding a novel acyl-CoA thioesterase (hACTE-III) was isolated as an HIV nef-binding protein by yeast two-hybrid system. hACTE-III is homologous to E. coli thioesterase II but to none of the mammalian thioesterases and therefore belongs to a new type. hACTE-III exhibits enzymatic specificity for a broad range of fatty acyl-CoAs. The hACTE-III-binding region within Nef is localized in the central region (amino acids 109-152). hACTE-III greatly enhances its enzymatic activity upon direct binding to Nef. Considering that either Nef-overexpression or impaired fatty acid regulation induces alteration of subcellular morphology, the augmented hACTE-III function by Nef-binding might induce dysfunction of T cells.

Amino Acid Sequence↗

PubMed1997

Adenovirus-mediated gene transfer of basic fibroblast growth factor induces in vitro angiogenesis.

To investigate the possibility of adenovirus-mediated gene transfer in the treatment of vascular occlusive diseases, we constructed a replication-deficient recombinant adenovirus vector coding for human basic fibroblast growth factor (bFGF) and examined its effect on the proliferation and differentiation of vascular endothelial cells in vitro. Human umbilical vein endothelial cells (HUVECs) were successfully infected with high efficiency and expressed 18 kD protein which is immunoreactive to anti-bFGF monoclonal antibody. This protein was accumulated mainly in the nuclei of the cells, but was also detected in the culture medium although the complimentary DNA (cDNA) did not contain the classical secreting signal sequence. The proliferation assay of HUVECs infected with bFGF-expressing adenovirus revealed a significant increase in cell number over control. Infection with this virus also enhanced tubular formation of HUVECs on reconstituted basement membrane. Neovascularization and the formation of collateral vessels play important roles in minimizing tissue damage in ischemic disorders. These results imply that the use of bFGF-expressing recombinant adenovirus may be a suitable in vivo gene therapy for ischemic diseases.

Adenoviridae↗

PubMed1997

Overexpression of c-fos inhibits down-regulation of a cyclin-dependent kinase-2 inhibitor p27Kip1 in splenic B cells activated by surface Ig cross-linking.

Splenic B cells activated by surface Ig (sIg) cross-linking transiently express the c-fos gene within 0.5 h and then enter into S phase of the cell cycle within 48 h. To investigate a role of c-fos in cell cycle progression, we used splenic B cells from IFN-alphabeta-inducible c-fos transgenic mice (Mx-c-fos). In the absence of IFN, the cell cycle progression of Mx-c-fos B cells stimulated with anti-IgM Ab was similar to that in control B cells. The cell cycle was arrested in G1 phase when we added IFN to the culture within 12 h after anti-IgM Ab stimulation, suggesting that overexpression of c-fos until mid-G1 phase perturbs activation of the cell cycle regulatory machinery. In control B cells, cyclin E and cdk2 were induced within 24 to 48 h after stimulation, and this induction was accompanied by down-regulation of a cdk2 inhibitor p27Kip1. As a consequence of these activation processes, cdk2 kinase activity was induced in B cells in the late G1 phase. However, kinase activity was not detected in Mx-c-fos B cells, presumably because the down-regulation of p27 was perturbed. These data suggest that c-Fos can negatively control cell cycle regulatory machinery in sIg-stimulated B cells.

Animals↗

PubMed1997

Cloning and sequencing of cDNA encoding NG,NG-dimethylarginine dimethylaminohydrolase from rat kidney.

Three cDNA clones encoding NG,NG-dimethylarginine dimethylamino-hydrolase (EC 3.5.3.18) have been isolated from a rat kidney lambda gt11 library using a probe prepared by PCR on the basis of partially determined amino-acid sequences of the enzyme. The sequence analyses of the cDNAs established that the 3008 bp cDNA contains 855 bp open reading frame encoding 285 amino acids (M(r) 31414), 3'-flanking region (1722 bp) and 5'-flanking region (431 bp). The amino-acid sequences of all the peptides isolated from the purified enzyme were shown to be included in the deduced amino-acid sequence. Northern blotting analyses showed that the mRNA (4 kb) is ubiquitously expressed in various rat tissues.

Amidohydrolases↗

PubMed1997

Induction of interleukin-2 unresponsiveness and down-regulation of the JAK-STAT system upon activation through the T cell receptor.

Full activation of T cells with antigen (Ag) and antigen-presenting cells initiates effector functions and proliferation. When T cells are re-stimulated through the T cell receptor (TCR) after a primary stimulation with Ag, growth arrest and cell death are induced. Activation of a T cell clone by cross-linking of TCR induces interleukin (IL)-2 unresponsiveness and ultimately cell death. While the proliferative signal delivered by IL-2 induces c-myc, bcl-2 and cyclin D3 expression, the expression of bcl-2 and cyclin D3 is completely suppressed upon TCR stimulation. Furthermore, TCR stimulation induces a decrease in the protein levels of JAK3 and STAT5, suggesting that IL-2 unresponsiveness and growth arrest of T cells result from down-regulation of JAK3 and STAT5.

Animals↗

PubMed1997

Th1 and Th2 subsets equally undergo Fas-dependent and -independent activation-induced cell death.

Stimulation of previously activated T cells results in apoptosis, termed activation-induced cell death (AICD). Recent analysis revealed that the Fas/Fas ligand (FasL) interaction is predominantly involved in AICD of T cells. Furthermore, based on the analysis of various T cell clones and lines, it has been reported that FasL is expressed mainly in Th1 but not in Th2 cells. However, the exact expression pattern of FasL and its function in normal activated T cells has not been determined. In the present study, by utilizing completely differentiated Th1 and Th2 cell populations obtained from ovalbumin-specific T cell receptor (TCR)-transgenic mice, the FasL expression on Th1 and Th2 was determined. Furthermore, involvement of Fas-FasL interaction in AICD of Th1 and Th2 cells was analyzed by two approaches: one was the inhibition of AICD by anti-FasL monoclonal antibodies, and the other AICD of Th1/Th2 subsets from TCR-transgenic mice backcrossed to lpr mice. We demonstrated that Th2 cells express FasL on the cell surface at a level similar to that expressed by Th1 cells, and that both subsets were equally susceptible to the Fas-mediated AICD. These observations suggest not only that the expression of FasL is not always correlated with Th subsets as defined by the cytokine-producing profile, but also that the responses of both Th1 and Th2 subsets are regulated by Fas-mediated AICD. Finally, analysis of the kinetics of AICD revealed a novel Fas/FasL-independent pathway in its initial stage. These findings revealed the precise function of Fas/FasL-mediated as well as Fas/FasL-independent AICD in the regulation of helper T cell responses.

Animals↗

PubMed1997

Tyrosine phosphorylation controls internalization of CTLA-4 by regulating its interaction with clathrin-associated adaptor complex AP-2.

CTLA-4 is a costimulation receptor that binds to the same ligands, CD80 and CD86, as CD28 with high affinity and is transiently expressed on the cell surface of activated T cells. CTLA-4 delivers an inhibitory signal through association of a phosphotyrosine-containing motif in the cytoplasmic domain with Syp tyrosine phosphatase. We now demonstrate that CTLA-4 interacts with the mu2 subunit of the plasma membrane-associated adaptor complex, AP-2, through the same motif involved in the interaction with Syp, except that the interaction with mu2 requires unphosphorylated tyrosine. The interaction with mu2 likely induces rapid internalization of CTLA-4 from the cell surface. Our results suggest that the phosphorylation state of a single tyrosine residue determines whether CTLA-4 delivers a negative signal or is internalized.

Abatacept↗

PubMed1997

Boron neutron capture therapy: preliminary study of BNCT with sodium borocaptate (Na2B1 2H1 1SH) on glioblastoma.

To plan the optimal BNCT using BSH for glioblastoma patients, the 10B concentration in tumor and blood was investigated in 11 newly diagnosed glioblastoma patients. All patients received 20 mg BSH/kg body weight 2.5-16 hrs prior to tumor removal. The quantitative distribution of 10B was determined by prompt gamma ray spectrometry and/or alpha-track autoradiography. 10B distribution in tumors was heterogeneous, +/- 25% of scattering at the microscopic level, and the distribution was also heterogeneous at the tissue level. 10B concentration in blood decreased in bi-exponential decay as a function of the time after the end of the administration. The T/B ratio showed non-exponential increase with large variation. The maximum T/B ratio would be around 1. The tumor/normal brain (T/N) ratio of 10B concentration was 11.0 +/- 3.2. The 10B content in normal brain is originated in vascular 10B in parenchyma, since the 10B content in normal brain to blood (N/B ratio) being compatible with the blood content in parenchyma. These values allow for BNCT, using thermal neutrons, on brain tumors located less than approximately 3.3 cm in depth from the brain surface of neutron incidence, providing that the dose on the normal endothelium is controlled to less than the tolerance limit. In our preliminary study of BNCT, a 31% 3-year survival was achieved over all for 16 glioblastoma patients and a 50% 2-year survival was achieved on 8 glioblastoma patients in our recent dose escalation study based on these data.

Borohydrides↗