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S Iwamoto

Publications and source records attributed to S Iwamoto.

At least 19 recordsLinked to original sources
PubMed2005

Identification and characterization of novel peroxisome proliferator-activated receptor-gamma (PPAR-gamma) transcriptional variants in pig and human.

The peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is a member of the steroid/thyroid/retinoid receptor superfamily, and is primarily expressed in fat tissue. To date, two major PPAR-gamma isoforms have been identified in pig, PPAR-gamma1 and PPAR-gamma2. Porcine PPAR-gamma1a consists of two leader exons, designated A1 and A2, followed by six exons containing the open reading frame. Here, we report the isolation and characterization of three novel PPAR-gamma1 transcripts. PPAR-gamma1b is derived from exon A1, with exon A2 spliced out. PPAR-gamma1c and PPAR-gamma1d are derived from the new exon, A', containing exon A2 (gamma1c) or without exon A2 (gamma1d). Based on PCR analysis of PAC clones that included sequences from the 5'-untranslated region of the PPAR-gamma gene, the new A' exon is located between the known exons A1 and A2. We also isolated the human homologue to exon A', as well as the two new PPAR-gamma1c and -gamma1d splice variants, from human adipose tissue. Studies of the expression of porcine PPAR-gamma by real time reverse transcription-polymerase chain reaction analysis show that transcripts derived from exon A1 were not expressed at significantly different levels in visceral fat (lamina subserosa) or subcutaneous fat (back fat, inner and outer layer). In contrast, exon A'-derived transcripts were expressed at progressively higher levels in the inner and outer layers of subcutaneous fat than in visceral fat. The same expression pattern was also observed for PPAR-gamma2. We hypothesize that there are three promoters, which differentially regulate PPAR-gamma1 and PPAR-gamma2 gene expression, depending on the specific localization of the fat tissue.

Alternative Splicing↗
PubMed2004

Precision control of the surface structure of gelatin films using micropit plates.

We attempted to use micropit plates as a silicon mold in order to control the surface structures of gelatin films. The three-dimensional micropit plates, fabricated with micromachining technology, have uniform quadrangular or circular pits with side lengths or diameters from 25-400 microm and depths of 40 microm. The micropit plates were originally hydrophilic because of silanol groups on the surface. In order to facilitate peeling the aqueous gelatin film from the micropit plates, the plate was therefore modified with hexamethyldisilazane. Gelatin films with precisely microfabricated structures on the surfaces were obtained by using the modified micropit plates. The release behavior of the films with different surface structures was examined.

Electroplating↗
PubMed2002

[Long-term results of aortic arch replacement using combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion; comparison of result for atherosclerotic aneurysm and aortic dissection].

Between 1992 and 2001, 73 patients with aortic arch lesion underwent surgical treatment. The aneurysm was characterized by atherosclerosis in 54 patients (TAA) and by aortic dissection in 19 patients (DAA). All patients received graft replacement under combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion. The hospital mortality rate for all patients was 15.6%. The follow-up period of 61 survival patients ranged from 2 to 90 months (mean 33.2 months). The actuarial survival rate was 93.2%, 83.5%, and 79.7% at 1, 3, and 5 years, respectively. No significant difference was noted between TAA and DAA in the actuarial survival rate. The freedom from vascular complication was 97.9%, 95.8%, and 95.8% at 1, 3, and 5 years, respectively. The rate was significant higher in the patients of DAA than in those of TAA (TAA: 100%, 100%, and 100%, DAA: 90.9%, 81.8%, and 81.8%). The freedom from cardiac complication was 96.4%, 89.7%, and 84.1% at 1, 3, and 5 years, respectively. There was no significant difference between TAA and DAA. The freedom from cerebrovascular complication was 100%, 97.6%, and 83.4% at 1, 3, and 5 years, respectively. No significant difference was noted between TAA and DAA. The late result of surgical treatment for the aortic arch using combination of deep hypothermic circulatory arrest and retrograde cerebral perfusion was satisfied. The long-term survival rate was higher in TAA patient than in DAA one. The possibility remained that fatal vascular complication affected the long-term survival rate.

Aged↗
PubMed2001

A pivotal role of Rho GTPase in the regulation of morphology and function of dendritic cells.

Dendritic cell (DC) is the most potent activator of CD4+ T cells and has unique dendrites and veils. To explore the function of Rho in DC, exoenzyme C3 from Clostridium botulinum was used as a specific inhibitor of Rho. Treatment of DC with C3 (DC/C3) resulted in profound morphological changes by losing dendrites and emerging of shrunk membrane processes that were in parallel with marked reduction of polymerized actin in the marginal area. Inactivation of Rho-associated coiled coil-containing kinase (p160ROCK) by a specific ROCK inhibitor Y-27632 also led to disappearance of dendrites of DC with retaining large membrane expansions. In scanning electron microscopy, untreated DCs interacted with CD4+ T cells more efficiently than DC/C3. Conjugate formation assay showed that the number of DCs associated with CD4+ T cells was 2-fold higher in untreated DCs than that of DC/C3. Alloantigen-presenting capacity of DC/C3 was significantly suppressed in a dose-dependent manner. Because C3 treatment did not affect the surface expression of HLA, costimulatory, and adhesion molecules of DC, we examined cytokine production of DC and naive CD4+ T cells to further elucidate the inhibitory mechanism of MLR. Unexpectedly, DC/C3 increased IL-12 production after LPS stimulation. Naive CD4+ T cells cocultured with DC/C3 produced the increased percentage of IFN-gamma-producing cells, whereas the percentage of IL-2-producing T cells was decreased. These results demonstrate that Rho GTPase in DC controls both characteristic shape and immunogenic capacity.

ADP Ribose Transferases↗
PubMed2001

Reactivity of autoantibodies of autoimmune hemolytic anemia with recombinant rhesus blood group antigens or anion transporter band3.

The specificity of autoantibodies in autoimmune hemolytic anemia (AIHA) has been studied using the serological procedure and immunoprecipitation technique with rare phenotype red cells. We attempted to analyze specificity using recombinant rhesus (Rh) blood group and band3 antigens expressed on erythroleukemic cell lines, KU812E. The autoantibody eluates were isolated by the acid elution procedure from the red cells of 20 AIHA patients. The recombinant Rh antigens, RhD, cE, ce, CE, and chimera antigens CE-D and D-CE, were obtained by retroviral cDNA transduction into KU812E cells, and the cell line expressing the antigens was cloned. Band3 cDNA was also obtained and introduced into KU812E and cloned KU812 expressing RhcE. The reactivities of AIHA eluates with recombinant Rh and band3 antigens were studied by flow cytometry. Fifteen eluates reacted with at least one of the RhcE, ce, or CE antigens, and four eluates reacted with RhD. Seven eluates with strong Rh specificity were studied further using chimera antigen. Five eluates showed reduced or lost reactivity, although two eluates reacted identically with the chimera antigens as wild type. These results indicated that conformational epitopes constituted by RhD or CE specific exofacial peptide loops are important for autoantibodies in most cases. Seven eluates reacted with band3, five exclusively. The coexpression study of RhcE and band3 did not enhance the expression of either antigen nor the reactivity with patient eluates, indicating that association of Rh and band3 was not involved in the appearance of autoantigen.

Anemia, Hemolytic, Autoimmune↗
PubMed2001

Regression of lymph node metastases by immunotherapy using autologous breast tumor-lysate pulsed dendritic cells: report of a case.

A 50-year-old woman was diagnosed as having stage IV breast cancer with bilateral supraclavicular lymph node metastasis resistant to CAF therapy. She received immunotherapy using autologous tumor lysate-pulsed dendritic cells (DCs). Four cycles of DC injection into the right supraclavicular lymph nodes resulted in regression of bilateral supraclavicular lymphogenous metastasis. Histological studies revealed an accumulation of CD45+ T lymphcytes in the regressive lymph nodes. This case suggests that immunotherapy with DCs may be a safe and promising approach for the treatment of advanced breast cancer.

Adjuvants, Immunologic↗
PubMed2001

Differential responsiveness of cord and adult blood monocytes to hepatocyte growth factor.

Monocytes as antigen-presenting cells play an important role in host defence. There are several cytokines affecting monocyte function. We demonstrate that both adult and cord blood monocytes constitutively express hepatocyte growth factor (HGF) receptor, MET. HGF significantly down-regulated MET expression of adult blood monocytes, compared with cord blood monocytes, when cultured either in RPMI-1640 containing 10% FBS or serum-free medium. Surface levels of MET correlated with c-met mRNA levels both in adult and cord blood when cultured. MET expression was down-regulated by treating with actinomycin D or cycloheximide. HGF stimulated DNA synthesis of adult monocytes, but not cord blood. HGF enhanced antigen-presenting capacity of adult blood monocytes but not cord blood monocytes. HGF up-regulated HLA class I expression in adult monocytes but not in cord blood monocytes. The current results suggest that the failure of cord blood monocytes to respond to HGF may be responsible, in large part, for their functional immaturity.

Adult↗
PubMed2001

Molecular characterization of weak D phenotypes by site-directed mutagenesis and expression of mutant Rh-green fluorescence protein fusions in K562 cells.

BACKGROUND AND OBJECTIVES: Mutations detected in 161 weak D samples from Caucasians have been classified into 16 types. Because flow cytometry using monoclonal anti-D antibodies (mAbs) has shown that weak D red cells display type-specific antigen density, these mutations in transmembranous regions have been assigned weak D phenotypes. The present study attempts to confirm or refute this assignment. MATERIALS AND METHODS: We amplified DNA from four Japanese weak D samples using the polymerase chain reaction (PCR), and directly sequenced the amplified DNA. Using site-directed mutagenesis, we constructed three vectors expressing mutant RHDs-- G212C, V270G (weak D type 1) and G358A (type 2)--in K562 cells. The expression of RhD antigens was examined by flow cytometry using mAbs. RESULTS: A new mutation resulting in a conversion at amino acid residue 212 (Gly to Cys) was detected in a Japanese weak D sample. K562 cells transduced with mutant RhD cDNA reacted weakly in a type-specific manner with mAbs. CONCLUSIONS: The mutations--G212C (new weak D type), V270G (weak D type 1) and G358A (type 2)-- in transmembranous regions had obvious effects on the D epitopes recognized by mAbs. The results of this study provide direct evidence that these mutations can account for weak D phenotypes.

Antibodies, Monoclonal↗
PubMed2001

Functional immaturity of cord blood monocytes as detected by impaired response to hepatocyte growth factor.

BACKGROUND: Monocytes as antigen-presenting cells play an important role in host defense and transplantation. However, there are little reports on cord blood monocytes, and the role of monocytes in cord blood transplantation is largely unknown. METHODS AND RESULTS: There are several cytokines affecting monocyte function. These include interferon-gamma, interleukin-4, interleukin-10, granulocyte macrophage-colony stimulating factor and hepatocyte growth factor (HGF). We investigated the effect of these cytokines on antigen-presenting capacity (APC) of cord and adult blood monocytes. Using either mononuclear cells or purified CD4+ T cells as responder cells, HGF enhanced APC of adult monocytes most effectively among these cytokines. In contrast, cord blood monocytes failed to respond to HGF. As HLA, costimulatory and adhesion molecules may affect APC function, we examined these antigens of monocytes following HGF stimulation. The HGF upregulated integrin alpha5 subunit (CD49e) and intercellular adhesion molecule-1 (CD54) was expressed in adult blood monocytes, but not in cord blood. In kinetic studies, HGF downregulated c-met protein/HGF receptor expression of adult monocytes in lower concentrations and at shorter incubation time as compared with that of cord blood. CONCLUSIONS: The results suggest that impaired response of cord blood monocytes to HGF may be responsible, in large part, for their functional immaturity.

Adult↗
PubMed2001

The p75 neurotrophin receptor, relative to other Schwann cell and melanoma markers, is abundantly Expressed in spindled melanomas.

Seventeen cases of spindled melanomas and eleven cases of epithelioid melanomas were immunolabeled with various melanoma and Schwann cell markers. Standard melanoma markers included S100, HMB45, HMB50, tyrosinase, and Melan A. Schwann cell markers included the p75 neurotrophin receptor (p75NTR), glial fibrillary acidic protein (GFAP), and the L1 adhesion protein. The degree of immunocytochemical labeling was scored by levels of both intensity and pervasiveness. The results confirmed a distinct difference in labeling between epithelioid and spindled melanomas. The p75NTR was strongly expressed in spindled melanomas and weakly expressed in the epithelioid melanomas. The usual melanoma markers, including HMB45, HMB50, MelanA, and tyrosinase had the reverse pattern, being strongly expressed in virtually all epithelioid melanomas, but rarely expressed in the spindled variants. S100 was unique among the markers in being expressed by both epithelioid and spindled melanomas. Glial fibrillary acidic protein and L1 adhesion protein were expressed moderately, with preferential labeling of the spindled melanomas. The greatest immunophenotypic difference between spindled and epithelioid melanomas was the high abundance of p75NTR expression in spindled melanomas. The functional significance of the high level of p75 neurotrophin receptor expression may contribute to the high predisposition of perineural extension in the desmoplastic subset of spindled melanomas.

Biomarkers, Tumor↗
PubMed2001

Expression of cell-cycle regulator p27 is correlated to the prognosis and ER expression in breast carcinoma patients.

Cell cycle inhibitor p27 is variously expressed in breast carcinoma. A possible association between the expression of p27 and the prognosis of breast carcinoma remains to be elucidated. We investigated the expression of p27 and cyclin D1 in a retrospective series of 216 breast carcinomas immunohistochemically. Expression of p27 (p27 LI) ranged from 0 to 93.6% (median 62.4%). There was a positive association between p27 LI and cyclin D1 (p < 0.01) and between p27 LI and ER (p < 0.0001). In the combination study of p27 LI and cyclin D1 expression, the patients classified as low p27 LI/cyclin D1 negative had a poorer prognosis than those in other categories. p27 was identified as an independent prognostic factor by the multivariate Cox proportional hazard model with a relative risk of death of disease of 4.1 (p < 0.05; vs. high p27 LI compared to the median). Assessment of p27 expression and examination of both p27 LI and cyclin D1 expression may identify breast carcinoma patients who would benefit from adjuvant therapy.

Adult↗
PubMed2001

The effect of anabolic steroid on the distribution of muscle fiber in rat hind limb.

This study evaluates the effect of anabolic steroid hormone (nandrolone decanoate, 19-Nortestosterone; ND) on histomorphometry and distribution of muscle fiber in the rat tibialis anterior (TA) muscle compared with the control rats. Three male Wistar rats aged of 5 weeks were daily received subcutaneous injection of 0.3 cc vehicle oil included 1mg ND for 6 weeks. Two control (C) rats were done only vehicle oil by the same manner as the experimental (E) group. The TA muscle was stained for myofibrillar adenosine triphosphatease with preincubation at pH 4.35, after cryosectioning at the thickness of 10 microm. Muscle fibers were classified into type I, IIA, IIX, and IIB. The E group showed significantly smaller than the C group in body weight. In histomorphometry, the cross-sectional area of type IIB fibers in the E group showed narrow range, and shifted smaller than those in the C groups. The distribution of type I fibers was restricted to the deep region in the E group. The anabolic steroid facilitated toward the older rat type on distribution and proportion of muscular tissue.

Aging↗
PubMed2000

Cloning and characterization of erythroid-specific DNase I-hypersensitive site in human rhesus-associated glycoprotein gene.

Rhesus-associated glycoprotein is a critical co-factor in the expression of rhesus blood group antigens. We identified and cloned an erythroid-specific major DNase I-hypersensitive site located about 10 kilobases upstream from the translation start site of the RHAG gene. A short core enhancer sequence of 195 base pairs that corresponded with the major hypersensitive site and possessed position- and orientation-independent enhancer activity in K562 cells. In vitro DNase I footprint analysis revealed four protected regions in the core enhancer; two GATA motifs, an Ets-like motif and an unknown motif. The GATA motifs bound GATA-1 and mutagenesis analysis revealed that the proximal one is critical for the enhancing activity. Homology plot analysis using the 5' sequence of the mouse RHAG gene revealed four homologous stretches and multiple insertions of repetitive sequences among them; four LINE/L1 and four Alu in the human and as well as one LINE/L1 and one LTR/MaLR in the mouse gene. The highly conservative enhancer region was flanked by SINE and LINE/L1 in both species. These results suggest that the 5'-flanking sequence of RHAG gene is a preferable target sequence for retroviral transposition and that the enhancer was inserted in the same manner, resulting in the acquisition of erythroid dominant expression.

Animals↗