Biomedical subjects

M Ogata

Publications and source records attributed to M Ogata.

At least 73 records · Page 4Linked to original sources

PubMed2000

[Transurethral removal of the ureter by the intussusception method in the treatment of renal pelvic and ureteral tumors].

Between August 1986 and December 1998, 19 patients who had renal pelvic and upper ureteral tumors were treated with nephrectomy and transurethral removal of the ureter using the intussusception method. Removal of the ureter failed in 5 patients because of excessive ablasion of the ureter or insufficient electro-resection around the ipsilateral ureteral orifice. Excluding those patients, the safety of the operation and the intravesical recurrence were compared with the outcome in 12 patients undergoing partial cystectomy for similar tumors. The mean operating time was not significantly shorter with the intussusception method compared with partial cystectomy (190.4 versus 251.3 minutes), but the mean blood loss was significantly smaller (187.5 versus 460.2 ml) and the intussusception method did not require a blood transfusion. The mean term of hospitalization was 20.3 days for patients treated by the intussusception method which was significantly shorter than that for patient undergoing partial cystectomy (25.4 days). Intravesical recurrence was found in seven patients (50%) treated by the intussusception method and the 1- and 5-year recurrence-free rates were 69.2% and 30.8% respectively. There was no significant difference in the recurrence-free rates between the two surgical techniques. These results suggest that the intussusception method is superior to partial cystectomy in decreasing the operating time, blood loss and term of hospitalization. It can be an attractive option in selected cases, without increasing the risk of intravesical recurrence.

Adult↗

PubMed2000

[A family with heat-sensitive myotonia alternating with hypokalemic periodic paralysis].

We report a 34-year-old man with evident family history of paralysis and myotonia. He has noticed episodic morning paralysis alternating with muscle myotonia since the age of 10 years. When an episode of paralysis occurred, his serum potassium level decreased to 2.3 mEq/L and tended to increase to about 4.0 mEq/L when he complained myotonia. This case is obviously different from several already-known diseases, as it is perhaps the first case thermo-sensitive disorder of muscle activity in that the myotonia is induced by warm environment but paralysis occurs in the setting of cold ambient temperature and hypokalemia. Therefore, we are underway to perform molecular genetic analysis of ion channels since paramyotonia/hyperkalemic periodic paralysis is known to be associated with Na(+)-channel missense mutations, while hypokalemic periodic paralysis is with Ca(++)-channel. Addendum: After submission of the manuscript, we identified a novel mutation in Na+ channel alpha subunit. The detail of molecular aspect will be reported elsewhere.

Adult↗

PubMed2000

[Leukocytopenia and thrombocytopenia preceded by human parvovirus B19 infection: report of three adult cases].

In Saiki City, Oita, Japan, erythema infectiosum in children has been prevalent from June, 1999 to the time of writing (January, 2000). We present three adult cases of parvovirus B19-associated leukocytopenia and thrombocytopenia that developed during this epidemic. Between June and November, 1999, a 32-year-old woman, a 38-year-old woman, and a 63-year-old man were referred to our hospital for treatment of leukocytopenia and thrombocytopenia. All complained of common cold-like symptoms. Their WBC counts (percentage of neutrophils) were 1,000/microliter (70%), 1,900/microliter (40%) and 1,680/microliter (40%), their hemoglobin levels 9.4 g/dl, 9.8 g/dl and 14.9 g/dl, and their platelet counts 10.8 x 10(4)/microliter, 6.9 x 10(4)/microliter and 4.5 x 10(4)/microliter, respectively. The diagnosis of parvovirus B19 infection was documented by the presence of B19-specific IgM antibodies or serum positivity for viral DNA. In two cases, the leukocytopenia and thrombocytopenia resolved gradually. In the other case, leukocytopenia, thrombocytopenia and B19 infection persisted for more than two months. These cases suggest that parvovirus B19 may be a common cause of leukocytopenia and thrombocytopenia even in adult patients without hematological disorders (erythropoietic stress), and that testing for parvovirus infection is justified in such patients, even if anemia is slight, especially when erythema infectiosum is prevalent.

Adult↗

PubMed2000

Bond strengths of self-etching primer adhesives to in vitro-demineralized dentin following mineralizing treatment.

PURPOSE: The purpose of this study was to determine if treatment of experimentally demineralized dentin with a calcium phosphate precipitating (CPP) solution could restore the bond strength of self-etching adhesives to that of normal mineralized control values. MATERIALS AND METHODS: The occlusal surfaces of human teeth were exposed for bonding. The teeth were assigned to a mineralized control group or one of three demineralized (40% phosphoric acid for 60 s) experimental groups. One of the experimental groups remained untreated, while the other two were treated with the CPP solutions for either 1 or 10 min. All experimental groups were then chemically dehydrated with ascending acetone concentrations to prevent shrinkage prior to bonding with Clearfil Liner Bond 2 (LB2) or MacBond II (MBII). Composite buildups were made and vertically, serially sectioned into multiple slabs about 0.7 mm thick. Each slab was then trimmed for microtensile bond testing and SEM examination. RESULTS: Both self-etching adhesives produced high bond strengths to control mineralized dentin (ca 42 and 37 MPa for LB2 and MBII, respectively). Acid etching with 40% phosphoric acid for 60 s followed by chemical dehydration significantly lowered (p < 0.05) bond strength to 26 and 27 MPa for LB2 and MBII, respectively, and created hybrid layers between 7 and 8 microns thick. When the demineralized dentin was treated with the CPP solution for 1 min, the bond strengths increased (p < 0.05) to 39 for LB2 and 42 MPa for MBII, and the hybrid layers were 11 microns thick. Increasing the CPP treatment time to 10 min lowered (p < 0.05) bond strengths but increased the hybrid layer thickness to 16 to 20 microns. CONCLUSION: The use of calcium phosphate precipitating solutions may permit higher bond strengths of self-etching primers to demineralized (e.g., caries-affected) dentin.

Acid Etching, Dental↗

PubMed1999

Estimating amounts of toluene inhaled by workers with protective mask using biological indicators of toluene.

Personal air samplers were attached to workers wearing protective masks to determine the levels of toluene vapor in the breathing zone. Concentrations of toluene in exhaled air, blood and urine; and hippuric acid and o-cresol concentrations in the urine of the workers were determined. Subsequently, toluene concentrations in the air inhaled by workers with and without gas masks were estimated by single and multiple regression equations. Analysis of single regression equations revealed that, compared with toluene concentrations in air, masks decreased the concentrations of the four biological exposure indicators: toluene in exhaled air, urinary toluene, urinary hippuric acid and urinary o-cresol by about 29% in average. Analysis by multiple regression equations showed a decrease of 38% in four biological indicators. Since average exposure to toluene in the shop was relatively low, the workers wore the masks only during high concentrations of toluene; they were, however, exposed to direct inhalation when the masks were removed in lower concentrations.

Adult↗

PubMed1999

Direct suppression of TCR-mediated activation of extracellular signal-regulated kinase by leukocyte protein tyrosine phosphatase, a tyrosine-specific phosphatase.

Leukocyte protein tyrosine phosphatase (LC-PTP)/hemopoietic PTP is a human cytoplasmic PTP that is predominantly expressed in the hemopoietic cells. Recently, it was reported that hemopoietic PTP inhibited TCR-mediated signal transduction. However, the precise mechanism of the inhibition was not identified. Here we report that extracellular signal-regulated kinase (ERK) is the direct target of LC-PTP. LC-PTP dephosphorylated ERK2 in vitro. Expression of wild-type LC-PTP in 293T cells suppressed the phosphorylation of ERK2 by a mutant MEK1, which was constitutively active regardless of upstream activation signals. No suppression of the phosphorylation was observed by LC-PTPCS, a catalytically inactive mutant. In Jurkat cells, LC-PTP suppressed the ERK and p38 mitogen-activated protein kinase cascades. LC-PTP and LC-PTPCS made complexes with ERK1, ERK2, and p38alpha, but not with the gain-of-function sevenmaker ERK2 mutant (D321N). A small deletion (aa 1-46) in the N-terminal portion of LC-PTP or Arg to Ala substitutions at aa 41 and 42 resulted in the loss of ERK binding activity. These LC-PTP mutants revealed little inhibition of the ERK cascade activated by TCR cross-linking. On the other hand, the wild-type LC-PTP did not suppress the phosphorylation of sevenmaker ERK2 mutant. Thus, the complex formation of LC-PTP with ERK is the essential mechanism for the suppression. Taken collectively, these results indicate that LC-PTP suppresses mitogen-activated protein kinase directly in vivo.

Calcium-Calmodulin-Dependent Protein Kinases↗

PubMed1999

Anti-tumor-promoting effects of phenylpropanoids on Epstein-Barr virus activation and two-stage mouse skin carcinogenesis.

In our joint project in the search for anti-tumor promoters from natural plant sources, we carried out a primary screening of 12 phenylpropanoids isolated from Boronia pinnata Sm. (Rutaceae) by examining their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All tested compounds in this study showed inhibitory activity against the EBV activation even at 1 x 10 mol ratio without any cytotoxicity. Among 12 phenylpropanoids tested, boropinal-C (1), boropinol-A (5), boropinol-C (9) and 3-(3'-methoxy-4'-prenyloxy)phenyl-1-propene (10), all having a 4'-(3-methylbut-2-enyloxy) group, a so-called prenyloxy group, showed more potent activities. Furthermore, 3-(3'-methoxy-4'-prenyloxy)phenyl-1-propene (10) also exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. This investigation indicated that certain phenylpropanoids might be valuable anti-tumor promoters.

Animals↗

PubMed1999

Regulation of phosphorylation level and distribution of PTP36, a putative protein tyrosine phosphatase, by cell-substrate adhesion.

Recently we have cloned a putative protein tyrosine phosphatase, PTP36/PTPD2/pez, which possesses a domain homologous to the N-terminal half of band 4.1 protein. In mouse fibroblasts adhered to substrates, PTP36 was phosphorylated on serine residues. PTP36 was found to make complexes with serine/threonine kinase(s), which phosphorylated PTP36 in vitro. PTP36 was dephosphorylated rapidly when the cell-substrate adhesion was disrupted and it was phosphorylated again along with the reattachment of the cells to fibronectin. Rephosphorylation of PTP36 seemed to depend on actin polymerization since it was inhibited by cytochalasin D. The cell detachment also induced the translocation of PTP36 into the membrane-associated cytoskeletal fraction. Staurosporine and ML-9, which inhibited the phosphorylation of PTP36 in vivo, induced the translocation of PTP36 too. On the contrary, when the dephosphorylation of PTP36 was inhibited by okadaic acid, no translocation of PTP36 was induced by the cell detachment. These results demonstrate that the cell-substrate adhesion and cell spreading regulates the intracellular localization of PTP36 most likely through its phosphorylation and therefore, PTP36 may play important roles in the signal transduction pathway of cell-adhesion.

Animals↗

PubMed1999

The transmembrane protein tyrosine phosphatase RPTPsigma modulates signaling of the epidermal growth factor receptor in A431 cells.

Attenuation of epidermal growth factor receptor signaling by the ganglioside G(M3) has previously been found to involve activation of an unknown protein-tyrosine phosphatase (PTP). In transient expression experiments we tested different PTPs for activation towards EGF receptor by G(M3). The transmembrane PTP RPTPsigma but not RPTPalpha or the SH2-domain PTP SHP-1 exhibited elevated activity towards EGF receptor in G(M3)-treated cells. The possible relevance of RPTPsigma for regulation of EGF receptor signaling activity was further explored in stable A431 cells lines inducibly expressing RPTPsigma or RPTPsigma antisense RNA. RPTPsigma expression clearly reduced EGF receptor phosphorylation. Also, soft agar colony formation of respective cell lines was reduced upon RPTPsigma expression whereas RPTPsigma antisense RNA expression augmented both, EGF receptor phosphorylation and soft agar colony formation. In addition, RPTPsigma antisense RNA expression rendered A431 cells resistant to inhibition of EGF receptor phosphorylation by G(M3). We propose that RPTPsigma participates in EGF receptor dephosphorylation in A431 cells, becomes activated by G(M3) via an unknown mechanism and is thereby capable to mediate attenuation of EGF receptor phosphorylation by G(M3).

Animals↗

PubMed1999

Simultaneous determination of the urinary metabolites of toluene, xylene and styrene using high-performance capillary electrophoresis. Comparison with high-performance liquid chromatography.

A simple and rapid method using high-performance capillary electrophoresis (HPCE) for the simultaneous determination of the urinary metabolites of toluene, xylene and styrene, plus creatinine and uric acid in human urine specimens and standard solutions is described. The compounds were well separated from each other on a fused-silica capillary utilizing a 20 mM sodium tetraborate buffer (pH 9.65) with 15 mM beta-cyclodextrin and UV detection at 200 and 225 nm. The total analysis time was less than 6 min per sample. The capillary zone electrophoresis (CZE) method shows a good correlation with the high-performance liquid chromatography (HPLC) method with respect to urinary hippuric acid concentrations in the urine specimens of subjects exposed to the vapors of a solvent mixture of toluene and xylene. In comparing these two techniques, HPCE was found to be superior to HPLC because the analysis time is shorter, and the separation of m-MHA and p-MHA takes a long time with HPLC.

Calibration↗

PubMed1999

Chemotactic response toward chemokines and its regulation by transforming growth factor-beta1 of murine bone marrow hematopoietic progenitor cell-derived different subset of dendritic cells.

Dendritic cells (DCs) are highly specialized antigen-presenting cells that distribute widely in all organs. DCs initiate the primary immune response and activate naive T cells and B cells responsible for the acquired immunity. In this study, CCR7 mRNA was proved to be expressed in DCs and their precursors derived from murine bone marrow-derived hematopoietic progenitor cells (HPCs), whereas CCR1 mRNA was expressed in both CD11b-/dullCD11c+ and CD11b+hiCD11c+ DC precursors. CCR6 mRNA was not detected in any murine DC populations. In agreement with the chemokine receptor mRNA expression by each population in the DC differentiation pathway, SLC (also termed as MIP-3beta), one of the ligands for CCR7, strongly and selectively chemoattracted both CD11b-/dullCD11c+ and CD11b+hiCD11c+ DC precursors (days 6 to 7) and more mature DCs (days 13 to 14). We have recently found that transforming growth factor-beta1 (TGF-beta1), a cytokine that is essential for the appearance of Langerhans cells in the skin, polarizes murine HPCs to generate Langerhans-like cells through monocyte/macrophage differentiation pathway. We observed here that TGF-beta1 not only inhibited the expression of CCR7 in DCs and DC precursors derived from HPCs, but also inhibited the migration of these cells in response to SLC. This is the first report describing the chemokine and chemokine receptors responsible for murine DC migration and downregulation of DC migration by TGF-beta1.

Animals↗

PubMed1999

Effects of overexpression of PTP36, a putative protein tyrosine phosphatase, on cell adhesion, cell growth, and cytoskeletons in HeLa cells.

Non-receptor-type putative protein tyrosine phosphatase-36 (PTP36), also known as PTPD2/Pez, possesses a domain homologous to the N-terminal half of band 4.1 protein. To gain insight into the biological function of PTP36, we established a HeLa cell line, HtTA/P36-9, in which the overexpression of PTP36 was inducible. PTP36 expressed in HeLa cells was enriched in the cytoskeleton near the plasma membrane. There was little endogenous PTP36 detectable in uninduced HtTA/P36-9 cells or in the parental HeLa cells. Upon induction of PTP36 overexpression, HtTA/P36-9 cells spread less well, grew more slowly, and adhered to the extracellular matrix proteins less well than uninduced cells. Moreover, decreases in the actin stress fibers and the number of focal adhesions were observed. The tyrosine phosphorylation of the focal adhesion kinase induced by lysophosphatidic acid was suppressed in the HtTA/P36-9 cells overexpressing PTP36. These results indicate that PTP36 affects cytoskeletons, cell adhesion, and cell growth, thus suggesting that PTP36 is involved in their regulatory processes.

Cell Adhesion↗

PubMed1999

Inactivation of mitogen-activated protein kinases by a mammalian tyrosine-specific phosphatase, PTPBR7.

Mitogen-activated protein kinase (MAPK) is inactivated through dephosphorylation of tyrosyl and threonyl regulatory sites. In yeast, both dual-specificity and tyrosine-specific phosphatases are involved in dephosphorylation. In mammals, however, no tyrosine-specific phosphatase has been identified molecularly to dephosphorylate MAPK in vivo. Recently, we and others have cloned a murine tyrosine-specific phosphatase, PTPBR7/PTP-SL, which is expressed predominantly in the brain. Here we report inactivation of the extracellular signal-regulated kinase (ERK) family MAPK by PTPBR7. PTPBR7 made complexes with ERK1/ERK2 in vivo and dephosphorylated ERK1 in vitro. When overexpressed in mammalian cells, wild-type PTPBR7 suppressed the phosphorylation and activation of ERK by epidermal growth factor (EGF), nerve growth factor (NGF), and constitutively active MEK1, a mutant MAPK kinase. In contrast, catalytically inactive and ERK-binding-deficient mutants revealed little inhibition on the ERK cascade. These results indicate that PTPBR7 suppresses MAPK directly in vivo.

Animals↗

PubMed1999

Transforming growth factor-beta1 polarizes murine hematopoietic progenitor cells to generate Langerhans cell-like dendritic cells through a monocyte/macrophage differentiation pathway.

We have recently demonstrated that CD11b-/dullCD11c+ and CD11b+hiCD11c+ dendritic cell (DC) precursor subsets represent two distinct DC differentiation pathways from murine bone marrow lineage-phenotype negative (Lin-)c-kit+ hematopoietic progenitor cells (HPCs) stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) + stem cell factor (SCF) + tumor necrosis factor alpha (TNFalpha). We show here that transforming growth factor-beta1 (TGF-beta1) significantly inhibits the generation of these CD11b-/dullCD11c+ and CD11b+hiCD11c+ DC precursors. Phenotypically, this inhibitory effect was accompanied by markedly suppressed expression of Ia and CD86 antigens as well as major histocompatibility complex (MHC) class II transactivator (CIITA) and CC-chemokine receptor 7 (CCR7) mRNAs in Lin-c-kit+ HPC cultures stimulated with GM-CSF + SCF + TNFalpha at day 6. TGF-beta1 could also suppress mature DC differentiation from CD11b+hiCD11c+ DC precursors, but not the differentiation from CD11b-/dullCD11c+ DC precursors. In the absence of TNFalpha, TGF-beta1 markedly suppressed the expression of CIITA and CCR7 mRNAs in GM-CSF + SCF-stimulated Lin-c-kit+ HPCs at either day 6 or day 12 and induced the differentiation solely into monocytes/macrophages as evident in morphology, active phagocytic, and endocytic activities. These cells expressed high levels of F4/80 and E-cadherin antigens, but low or undetectable levels of Ia, CD86, and CD40 molecules. However, upon the stimulation with TNFalpha + GM-CSF, these cells could further differentiate into mature DCs expressing high levels of Ia and E-cadherin, characteristics for Langerhans cells (LCs), and gained the capacity of enhancing allogenic MLR. Taken together, all of these findings suggest that TGF-beta1 polarizes murine HPCs to generate LC-like DCs through a monocyte/macrophage differentiation pathway.

Animals↗

PubMed1999

Neuron-specific enolase as an effective immunohistochemical marker for injured axons after fatal brain injury.

Recently, it has been reported that a diagnosis of diffuse axonal injury in cases with a short survival period can be made with the use of immunolabelling for beta-amyloid precursor protein (APP). We examined whether immunostaining for neuron-specific enolase (NSE) can also be a useful marker for the detection of axonal injury in its early stages. Sections of the corpus callosum from 19 cases of head injury and from 9 cases of no head injury were immunostained for NSE and stained by the standard Holmes' silver method. For comparison, serial sections from several cases were immunostained for APP. Immunostaining for NSE as well as for APP, labelled injured axons in head injury cases with as early as 1.5 h survival where Holmes' staining failed to detect any changes of axons. Since NSE and APP labelled only injured axons but not normal axons, the results were readily interpretable. These findings indicate that NSE should be an effective marker for the detection of axonal injury in its early stages.

Adolescent↗

PubMed1999

Influence of TNF microsatellite polymorphisms (TNFa) on age-at-onset of insulin-dependent diabetes mellitus.

The TNF-alpha gene is located in the HLA region and has been implicated in the pathogenesis of Type I (insulin-dependent) diabetes mellitus (IDDM). We investigated the frequency of TNFa microsatellite alleles in 76 young-onset IDDM patients, 65 adult-onset IDDM patients, and 90 control subjects. We also examined the association of these TNFa alleles with HLA-DRB1 alleles, HLA-class I alleles, and TNF-alpha production. The frequency of the TNFa2 and TNFa9 alleles was increased in the young-onset IDDM patients compared to control subjects, but the increased frequency of TNFa2 was not significant after the correction for the number of comparisons was made. We did not find any association of TNFa2 or TNFa9 with any of the HLA-DRB1 alleles. In contrast, the frequency of the TNFa13 allele was decreased in both the young-onset and the adult-onset IDDM patients compared to the control subjects, but the difference lost significance after the correction was made in the adult-onset IDDM. The TNFa13 allele was strongly associated with DRB1*1502. Patients with TNFa2 or TNFa9 had greater TNF-alpha production, while those positive for TNFa13 had lower TNF-alpha production than patients with non-TNFa2, a9, and a13 alleles. These results suggest that TNFa polymorphisms are associated with age-at-onset of IDDM and influence the inflammatory process of pancreatic beta cell destruction in the development of IDDM.

Adolescent↗

PubMed1999

Extracellular matrixes influence alpha-smooth muscle actin expression in cultured porcine lens epithelial cells.

PURPOSE: To determine whether extracellular matrix (ECM) influences the expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in cultured porcine lens epithelial cells (LECs). METHODS: Porcine LECs were cultured for 6 days in an F-12 nutrient mixture supplemented with 5% fetal bovine serum on wells that were coated with laminin, fibronectin, type I collagen, or type IV collagen. LECs cultured on uncoated wells served as a control. Alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the ratio of the number of alpha-SMA-positive cells to the total number of cells, the P/T ratio, was calculated. RESULTS: The P/T ratio of the LECs on the uncoated dishes was about 5%. LECs cultured on wells coated with laminin or type IV collagen significantly reduced the ratio, whereas fibronectin or type I collagen had no effect. CONCLUSIONS: The ECM influences alpha-SMA expression in cultured porcine LECs.

Actins↗

PubMed1999

Translocation of tyrosine-phosphorylated TCRzeta chain to glycolipid-enriched membrane domains upon T cell activation.

Recent studies point to glycolipid-enriched membrane (GEM) microdomains as the critical sites for TCR-mediated signal transduction. However, whether the TCR complex is localized in the GEM domain is not well-defined. In the present study, we analyzed localization of the TCR-CD3 complex in the GEM domain by isolating the GEM fraction with sucrose density gradient centrifugation. Although 10% of TCRzeta chains was localized in the GEM fraction, most of the TCR complexes were excluded from the GEM before and after T cell activation, and the amount of TCRzeta in the GEM was not increased after activation. However, the tyrosine-phosphorylated form of TCRzeta was strongly concentrated in the GEM fraction upon TCR engagement. A kinetic study revealed that tyrosine phosphorylation of TCRzeta occurred initially in the Triton X-100-soluble membrane fraction followed by the accumulation of phosphorylated TCRzeta in the GEM. Thus, these results indicate that phosphorylated TCRzeta migrates into the GEM domains on T cell activation. We speculate that the GEM microdomains may function as a reservoir of activation signals from triggered TCR.

Animals↗