Ken-Ichi Hakamada

Hirosaki University, Khirosaki, Aomori, Japan

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Publications (3)8.33 Total impact

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    ABSTRACT: Pancreatic endocrine tumor (PET) presents variable clinical features. Five subtypes of somatostatin receptor (SSTR) are involved in hormone secretion and cell proliferation. In this paper, we explore the correlation between the SSTR subtype messenger RNA (mRNA) expression and clinicopathological features of PET. Twenty-one cases of PET and 5 cases of pancreatic adenocarcinomas (AC) were studied. Using total RNA extracted from paraffin sections and fresh tissues, SSTR subtype mRNA was quantified by real-time polymerase chain reaction. The hormones and MIB1 index were examined using immunohistochemical techniques. The mRNA levels of SSTR1, SSTR2, SSTR3, and SSTR5 were high in PET compared with AC, whereas the expression of SSTR4 was low in PET and AC. Levels of each subtype did not vary with histological grades. Somatostatin receptor 2 levels in functioning tumors were slightly low compared with nonfunctioning tumors. Four distinct groups of PET were identified by hierarchical cluster analysis, and two of these groups showed reduced SSTR5 with elevation of MIB1 index. The study showed a heterogeneous expression profile of SSTR subtype mRNA and the association of reduction in SSTR5 with high proliferative activity. Such profiling of SSTR subtypes may provide useful information on tumor biology and treatment of PET.
    No preview · Article · Nov 2010 · Pancreas
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    ABSTRACT: Proteoglycans (PGs) are complex glycohydrates which are widely distributed in extracellular matrix (ECM). PGs are involved in the construction of ECM, cell proliferation and differentiation. ECM components are involved in transduction of proinflammatory responses, but it is still unknown whether PGs are involved in inflammatory response. In this study, we investigated the effect of PG extracted from salmon cartilage on the progression of experimental colitis-induced in severe combined immunodeficiency mice by cell transfer from interleukin-10 (IL-10)-/- mice. IL-10-/- cell-transferred mice showed weight loss, colon shortening and histological appearance of mild colitis. Daily oral administration of PG attenuated the clinical progression of colitis in a dose-dependent manner. Colitis-induced mice showed the elevated expression of IFN-γ, IL-12, TNF-α, IL-21, IL-23p19, IL-6, IL-17A and retinoic acid-related orphan receptor γt (RORγt) in lamina propria mononuclear cells (LPMCs) and oral administration of PG suppressed the expression of these factors. Conversely, expression of Foxp3 that induces CD4+CD25+ regulatory T cells in LPMCs was enhanced by PG administration. These findings suggested that salmon PG attenuated the progression of colitis due to suppression of inflammatory response by enhancement of regulatory T cell induction.
    No preview · Article · Oct 2010 · Biochemical and Biophysical Research Communications
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    ABSTRACT: We investigated the effect of p60, a virulence factor of Listeria monocytogenes, on host immune response in vitro and in vivo. Administration of p60 before a sublethal infection with L. monocytogenes enhanced innate host resistance in naïve mice. Mouse macrophage RAW264.7 cells produced tumor necrosis factor (TNF)-alpha in response to stimulation with recombinant p60. Toll-like receptor 4 may be involved in TNF-alpha production from RAW264.7 cells and enhanced host resistance induced by p60 administration. Our findings demonstrated that p60 modulates innate immune responses against L. monocytogenes infection.
    Full-text · Article · Mar 2010 · FEMS Immunology & Medical Microbiology