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Biomedical subjects

M Narimatsu

Publications and source records attributed to M Narimatsu.

At least 19 recordsLinked to original sources
PubMed2004

In vitro estrogenicity of resin composites.

Previously, we have reported that sealants incorporating bisphenol A dimethacrylate showed estrogenicity by a reporter gene assay. This study tested the hypothesis that commercial composites, which contain various monomers and additives, exhibit estrogenic activity in vitro. The estrogenic activities of eluates obtained from 24 composites and 18 chemicals identified from the composites tested were examined with the use of the reporter gene assay. Among the 24 composites, 6 products were estrogenic, and among the 18 constituents, 1 photostabilizer, 2-hydroxy-4-methoxy-benzophenone (HMBP), 1 photoinitiator, 2,2-dimethoxy-2-phenyl-acetophenone (DMPA), and 1 inhibitor, 2,6-di-tert-butyl-p-cresol (BHT) had significant estrogenic activity. The concentration of HMBP in 4 estrogenic eluates was greater than the minimum concentration required for estrogenicity, and DMPA was found at a higher level than the minimum estrogenic concentration in the remaining 2 estrogenic specimens. These results suggest that the observed estrogenic activity of 6 composites is associated with the elution of either HMBP or DMPA.

Acetophenones↗
PubMed2001

Tissue-specific autoregulation of the stat3 gene and its role in interleukin-6-induced survival signals in T cells.

Signal transducer and activator of transcription 3 (STAT3) mediates signals of various growth factors and cytokines, including interleukin-6 (IL-6). In certain IL-6-responsive cell lines, the stat3 gene is autoregulated by STAT3 through a composite IL-6 response element in its promoter that contains a STAT3-binding element (SBE) and a cyclic AMP-responsive element. To reveal the nature and roles of the stat3 autoregulation in vivo, we generated mice that harbor a mutation in the SBE (stat3(mSBE)). The intact SBE was crucial for IL-6-induced stat3 gene activation in the spleen, especially in the red pulp region, the kidney, and both mature and immature T lymphocytes. The SBE was not required, however, for IL-6-induced stat3 gene activation in hepatocytes. T lymphocytes from the stat3(mSBE/mSBE) mice were more susceptible to apoptosis despite the presence of IL-6 than those from wild-type mice. Consistent with this, IL-6-dependent activation of the Pim-1 and junB genes, direct target genes for STAT3, was attenuated in T lymphocytes of the stat3(mSBE/mSBE) mice. Thus, the tissue-specific autoregulation of the stat3 gene operates in vivo and plays a role in IL-6-induced antiapoptotic signaling in T cells.

Animals↗
PubMed2000

Successfully treated descending necrotizing mediastinitis through mediansternotomy using a pedicled omental flap.

A 21-year-old man with an oropharyngeal abscess admitted to our institution was initially treated with systemic antibiotics but was referred to our department when his condition rapidly deteriorated. His respiratory insufficiency required circulatory support. A computed tomographic scan showed a parapharyngeal abscess descending into the mediastinum with multiple right-side capsulized empyema and pericardial effusion. We conducted emergency surgery through a mediansternotomy using a pedicled omental flap. Postoperative clinical and radiologic assessment showed a normal chest X-ray and primary wound healing without sternal dehiscence. Mediansternotomy using a pedicled omental flap offers excellent exposure for a complete one-stage operation with debridement of all affected tissues of the subauricular region, the mediastinum, and both pleural cavities. We conclude that this method yields good results for patients with acute widespread descending necrotizing mediastinitis.

Adult↗
PubMed2000

Dissection of signaling cascades through gp130 in vivo: reciprocal roles for STAT3- and SHP2-mediated signals in immune responses.

We generated a series of knockin mouse lines, in which the cytokine receptor gp130-dependent STAT3 and/or SHP2 signals were disrupted, by replacing the mouse gp130 gene with human gp130 mutant cDNAs. The SHP2 signal-deficient mice (gp130F759/F759 were born normal but displayed splenomegaly and lymphadenopathy and an enhanced acute phase reaction. In contrast, the STAT3 signal-deficient mice (gp130FXQ/FXXQ) died perinatally, like the gp130-deficient mice (gp130D/D). The gp130F759/F759 mice showed prolonged gp130-induced STAT3 activation, indicating a negative regulatory role for SHP2. Th1-type cytokine production and IgG2a and IgG2b production were increased in the gp130F759/F759 mice, while they were decreased in the gp130FXXQ/FXXQ immune system. These results indicate that the balance of positive and negative signals generated through gp130 regulates the immune responses.

Acute-Phase Reaction↗
PubMed2000

Role of Gab1 in heart, placenta, and skin development and growth factor- and cytokine-induced extracellular signal-regulated kinase mitogen-activated protein kinase activation.

Gab1 is a member of the Gab/DOS (Daughter of Sevenless) family of adapter molecules, which contain a pleckstrin homology (PH) domain and potential binding sites for SH2 and SH3 domains. Gab1 is tyrosine phosphorylated upon stimulation of various cytokines, growth factors, and antigen receptors in cell lines and interacts with signaling molecules, such as SHP-2 and phosphatidylinositol 3-kinase, although its biological roles have not yet been established. To reveal the functions of Gab1 in vivo, we generated mice lacking Gab1 by gene targeting. Gab1-deficient embryos died in utero and displayed developmental defects in the heart, placenta, and skin, which were similar to phenotypes observed in mice lacking signals of the hepatocyte growth factor/scatter factor, platelet-derived growth factor, and epidermal growth factor pathways. Consistent with these observations, extracellular signal-regulated kinase mitogen-activated protein (ERK MAP) kinases were activated at much lower levels in cells from Gab1-deficient embryos in response to these growth factors or to stimulation of the cytokine receptor gp130. These results indicate that Gab1 is a common player in a broad range of growth factor and cytokine signaling pathways linking ERK MAP kinase activation.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Estrogenicity of fissure sealants and adhesive resins determined by reporter gene assay.

It is controversial whether the dental resinous materials containing 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), which is synthesized from the estrogenic compound bisphenol A (BPA), include unreacted BPA and/or can mimic the effects of natural steroid hormones. In the present study, the estrogenic activities of 3 fissure sealants and 5 adhesive resins, which were all unpolymerized, were determined by means of a reporter gene assay, and the relevance of the components to the estrogenicity was investigated. Two commercially available sealants were confirmed to have estrogenic activity, although none of the tested materials contained BPA. In contrast, hydrophobic monomer bisphenol A dimethacrylate (BPA-DMA), which is also estrogenic, was found to be included in these estrogenic sealants in an amount greater than the minimum concentration to show estrogenicity. This suggests that the estrogenicity of the two proprietary sealants was associated with BPA-DMA rather than with BPA.

Analysis of Variance↗
PubMed1999

STAT3 is required for the gp130-mediated full activation of the c-myc gene.

The signal transducers and activators of transcription (STAT) family members have been implicated in regulating the growth, differentiation, and death of normal and transformed cells in response to either extracellular stimuli, including cytokines and growth factors, or intracellular tyrosine kinases. c-myc expression is coordinately regulated by multiple signals in these diverse cellular responses. We show that STAT3 mostly mediates the rapid activation of the c-myc gene upon stimulation of the interleukin (IL)-6 receptor or gp130, a signal transducing subunit of the receptor complexes for the IL-6 cytokine family. STAT3 does so most likely by binding to cis-regulatory region(s) of the c-myc gene. We show that STAT3 binds to a region overlapping with the E2F site in the c-myc promoter and this site is critical for the c-myc gene promoter- driven transcriptional activation by IL-6 or gp130 signals. This is the first identification of the linkage between a member of the STAT family and the c-myc gene activation, and also explains how the IL-6 family of cytokines is capable of inducing the expression of the c-myc gene.

Animals↗
PubMed1999

Pericardio-peritoneal drainage using a subcostal approach.

A 56-year-old man admitted to our hospital for cardiac tamponade due to dilated cardiomyopathy did not respond to treatment by usual medical means or surgery. Pericardio-peritoneal drainage was conducted using a subcostal approach. Seven months later, the patient remains well and free of signs of pericardial tamponade. This method has proved to be safe and effective in patients with persistent massive pericardial effusion.

Cardiac Tamponade↗
PubMed1998

Therapeutic usefulness of wild-type p53 gene introduction in a p53-null anaplastic thyroid carcinoma cell line.

Anaplastic thyroid carcinomas very often harbor the mutations in the tumor suppressor gene p53. We have previously shown that wild-type (wt) p53 gene introduction led to cell growth arrest, but not apoptosis, in p53-null anaplastic thyroid carcinoma cells. The present studies were designed to evaluate other therapeutic effects of wt-p53 gene introduction on p53-null thyroid carcinoma cells, as chemo- and radiosensitization and inhibition of angiogenesis have also been described recently as additional therapeutic advantages of wt-p53 gene introduction in tumor cells with p53 mutations. A p53-null anaplastic thyroid carcinoma cell line, FRO, and a FRO subline stably expressing a temperature-sensitive (ts) mutant of p53 (p53Val138), tsFRO, were used. ts-p53 functions as mutant and wt at nonpermissive (37 C) and permissive (32 C) temperatures, respectively. tsFRO showed a prolonged cell doubling time compared to parental FRO when cultured at 32 C, but the cell growth rate was similar between FRO and tsFRO at 37 C. The cytotoxic and clonogenic assays demonstrated that although the sensitivity to three different anticancer agents (cisplatin, 5-fluorocytosine, and doxorubicin) was unaltered, radiosensitivity was enhanced in tsFRO compared to FRO at 32 C. Unexpectedly, in studies on angiogenesis, expression levels of vascular endothelial growth factor (an angiogenic factor) messenger ribonucleic acid were similar between FRO and tsFRO, and thrombospondin-1 (an antiangiogenic factor) messenger ribonucleic acid and protein levels were about 2.5-fold lower in tsFRO than FRO at 32 C, although any difference could not be detected in their ability to inhibit in vitro angiogenesis with the culture medium conditioned by tsFRO and FRO at 32 C. These results suggest that p53-defective thyroid carcinomas may benefit from the combination of p53 gene therapy and radiotherapy. However, further study will be necessary to clarify the pathological significance of thrombospondin-1 in angiogenesis and thyroid tumor growth.

Antimetabolites, Antineoplastic↗
PubMed1998

Coronary revascularization and abdominal aortic aneurysm repair in a patient with Behçet's diseases.

Behçet's disease is a systemic disease characterized by oral aphta, genital ulcer, and ocular lesion. Arterial involvement is an uncommon complication of Behçet's disease, and it most frequently affects the abdominal aorta followed by the femoral artery and the pulmonary artery. Coronary lesions in Behçet's disease have been little reported in the literature. In this communication, we present a case with coronary artery stenosis and with subsequently developed supra-renal abdominal aortic aneurysm. The coronary lesions were revasculized with gastroepiploic artery, right internal mammary artery, and saphenous vein graft. Abdominal aortic repair was performed with partial cardiopulmonary stand by, because of the risk of coronary ischemia during the cross clamp including the celiac artery. To our knowledge, this is the first report of successful repair of combined lesions of the coronary and the abdominal aorta in a patient with Behçet's disease.

Aortic Aneurysm, Abdominal↗
PubMed1997

Association of Stat3-dependent transcriptional activation of p19INK4D with IL-6-induced growth arrest.

Signal transducer and activator of transcription 3 (Stat3) is the major mediator of the IL-6-induced signals regulating growth and differentiation. In the M1 myeloleukemic cell line, Stat3 is a critical transcription factor causing repression of c-myc and c-myb genes, expression of junB and IRF1, growth arrest at G1, and subsequent macrophage differentiation. To understand the mechanisms by which Stat3 causes such effects, we searched for other Stat3-regulated genes possibly involved in growth arrest. We identified this inducible molecule as p19INK4D using a specific antibody. Both p19INK4D mRNA and protein were rapidly induced by IL-6 treatment without requiring de novo protein synthesis and the induction was fully suppressed by dominant-negative forms of Stat3. Thus both Stat3-regulated events, repressions of c-myc and c-myb and induction of p19INK4D, are likely to be involved in IL-6-induced growth arrest in M1 cells.

Animals↗
PubMed1997

Stiff-man syndrome associated with antecedent myasthenia gravis and organ-specific autoimmunopathy.

We describe a case of stiff-man syndrome accompanied by diabetes mellitus, Hashimoto's thyroiditis and the antecedent myasthenia gravis. The diagnosis of stiff-man syndrome was made based on not only clinical findings and the characteristic electromyographic pattern but also the presence of antibodies to glutamic acid decarboxylase in the serum and cerebrospinal fluid. Stiff-man syndrome is known to be associated with organ-specific autoimmunopathy including insulin-dependent diabetes mellitus. The present case is the first one that stiff-man syndrome was preceded by myasthenia gravis of organ-specific autoimmunopathy. Stiff-man syndrome in the present case probably represents the one of fully expressed manifestations from the broad spectrum of organ-specific autoimmunopathy caused by the loss of self-tolerance.

Adult↗
PubMed1997

[Stanford type A aortic dissection with closed false lumen: analysis of prognostic factors at initial CT or MRI].

Nineteen patients with Stanford type A acute aortic dissection with closed false lumen were reviewed. In the follow-up examinations, ulcerlike projection (ULP) in the ascending aorta (AA) or aortic arch (AR) was identified in 8 of 19 patients. In 5 of these 8 patients, acute cardiac tamponade occurred and 3 of them died. In the other 11 patients, there was no mortality, and only one patient underwent elective surgery. The appearance of ULP in the AA/AR is considered an indication for urgent surgery because it is regarded as a precursor of lethal complications such as cardiac tamponade. The purpose of this study was to investigate predictors of the appearance of ULP in the AA/AR with early imagings (CT or MRI) before the appearance of ULP. The patients were divided into two groups: patients with ULP in the AA/AR (8 patients) and others (11 patients). Initial CT or MRI findings of the thoracic aorta were retrospectively statistically analyzed in each group. Three predictive factors were statistically significant for the appearance of ULP in the AA/AR (diameter of the AA > or = 5 cm, thickness of the false lumen of the AA > or = 1 cm, thickness of the false lumen of the AA > or = that of the descending aorta). Close attention should be paid, if any of these 3 factors is observed at initial CT or MRI.

Aged↗
PubMed1996

The role of low-density lipoprotein apheresis as postoperative care of bypass grafting for chronic arterial occlusion.

Since November 1989, low-density lipoprotein apheresis has been applied to patients with intractable hyperlipidaemia following bypass grafting for chronic arterial occlusion of the lower extremities. The treatment group comprised six patients (four men, two women) with arteriosclerosis obliterans. In five patients, the ankle pressure index deteriorated and intermittent claudication recurred due to atherosclerotic progression. Results of low-density lipoprotein apheresis were dramatic; the deteriorated ankle pressure index and intermittent claudication improved significantly after several applications of low-density lipoprotein apheresis. Significant angiographic improvement was obtained in two patients. It is concluded that low-density lipoprotein apheresis appears to be an efficient method to preserve graft patency and treat postoperative patients with deteriorated ankle pressure index.

Angiography↗
PubMed1993

[Axillo-femoral bypass for adult form of extreme coarctation of the aorta--the long term prognosis].

A 33-year-old female with adult form of extreme coarctation underwent axillo-femoral bypass grafting. The postoperative hemodynamic improvement was remarkable. The patient spent excellent quality of life without any hypotensive drug or anticoagulant agent for 14 years until pseudoaneurysms of the bypass graft ruptured. The patient was saved by an emergency operation with 2 steps of surgical procedures. The first step was making the new axillo-femoral bypass at the contralateral side, then the diseased graft was replaced by a new graft as the second step. The postoperative catheterization revealed no pressure gradient between the upper and lower extremities, and the bilateral API's were over 100%. The pseudoaneurysm of the graft seemed to be caused by the stabbed needle holes for the dearing of the graft and the instrument for the partial occlusion of the graft. We learned from this experience that the needle holes of the graft should be repaired by plegeted sutures, and Fogarty clamp or the clamp with rubber sheath should be used for clamping graft. The axillo-femoral bypass is, of course, not a first choice procedure for extreme coarctation, but the hemodynamic improvement was achieved in our case. Therefore, it may be still useful for the compromised host as an alternative procedure to the radical correction.

Adult↗