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Biomedical subjects

S Ohno

Publications and source records attributed to S Ohno.

At least 199 records · Page 11Linked to original sources
PubMed2000

[Sjögren's syndrome with multiple bullae and pulmonary nodular amyloidosis].

We report a case of Sjögren's syndrome with pulmonary involvement diagnosed by open lung biopsy. The patient was a 62-year-old woman with antiphospholipid antibody syndrome. Her chest radiograph and CT scan showed multiple bullae diffusely scattered throughout the lung. The open lung biopsy specimens revealed marked inflammatory mononuclear cell infiltration and nodular amyloid deposits in the bronchiolar walls. The mechanism of bulla formation appeared to be the check valve mechanism caused by the narrowing of the airway by the bronchiolitis. The patient was treated with oral corticosteroids, and her symptoms and laboratory findings became stable.

Amyloidosis↗
PubMed2000

Prognostic factors in node-negative squamous cell carcinoma of the thoracic esophagus.

BACKGROUND: Among several clinicopathological factors influencing the outcome of patients with esophageal carcinoma, the presence or absence of lymph node metastasis is the most important. Prognostic indicators, however, in patients without lymph node involvement have not been fully understood. MATERIALS AND METHODS: Out of 247 patients with primary squamous cell carcinoma of the thoracic esophagus between February 1981 and December 1998, 154 patients (62.3%) underwent esophagectomy with curative intent; 78 patients (50.6%) had no lymph node metastasis. Clinicopathological characteristics of those node-negative 78 patients were investigated. RESULTS: Pathological tumor stages (pT) were pT1 in 44 patients, pT2 in 24 patients, pT3 in 9 patients, and pT4 in one patient. Forty-six patients are alive free of cancer and another one with pT2N0 tumor is alive with recurrence. Four patients died of recurrence; one in pT1 and three in pT3. The remaining 27 patients died of miscellaneous causes other than esophageal cancer. The 1-, 3-, 5-, and 10-year overall survival rates of all 78 patients including in-hospital mortality were 86.3%, 73%, 66.5%, and 34.6%, respectively. The 3- and 5-year survival rates were 75.4% and 67.7% for those with pT1, T2 tumor (n = 68) and 57.1% and 57.1% for those with pT3, T4 tumor (n = 10) (p = 0.0151). The factors influencing overall survival rate were patient age (< 65 vs. > or = 65), depth of invasion (pT1,T2 vs. pT3, T4), time of operation (< or = 420 min vs. > 420 min), and estimated blood loss (< or = 810 ml vs. > 810 ml). More elderly patients died of unrelated causes to esophageal cancer than younger patients. Among those four variables, the patient age (p = 0.0114) and depth of invasion (p = 0.0443) were independent prognosticators for survival determined by multivariate analysis. CONCLUSION: For follow-up of elderly patients with node-negative esophageal cancer, evaluation of medical problems is more important than detection of recurrence. pT2N0 stage tumors should be considered a group with an excellent prognosis like pT1N0 tumors.

Aged↗
PubMed1999

Deregulated expression of c-Myc in a translocation-negative plasmacytoma on extrachromosomal elements that carry IgH and myc genes.

The induced expression of c-Myc in plasmacytomas in BALB/c mice is regularly associated with nonrandom chromosomal translocations that juxtapose the c-myc gene to one of the Ig loci on chromosome 12 (IgH), 6 (IgK), or 16 (IgL). The DCPC21 plasmacytoma belongs to a small group of plasmacytomas that are unusual in that they appear to be translocation-negative. In this paper, we show the absence of any c-myc-activating chromosomal translocation for the DCPC21 by using fluorescent in situ hybridization, chromosome painting, and spectral karyotyping. We find that DCPC21 harbors c-myc and IgH genes on extrachromosomal elements (EEs) from which c-myc is transcribed, as shown by c-myc mRNA tracks and extrachromosomal gene transfer experiments. The transcriptional activity of these EEs is supported further by the presence of the transcription-associated phosphorylation of histone H3 (H3P) on the EEs. Thus, our data suggest that in this plasmacytoma, c-Myc expression is achieved by an alternative mechanism. The expression of the c-Myc oncoprotein is initiated outside the chromosomal locations of the c-myc gene, i.e., from EEs, which can be considered functional genetic units. Our data also imply that other "translocation-negative" experimental and human tumors with fusion transcripts or oncogenic activation may indeed carry translocation(s), however, in an extrachromosomal form.

Animals↗
PubMed1999

Diabetes alters neurite regeneration from mouse retinal explants in culture.

We examined the effect of experimental diabetes on neurite regeneration from adult mouse retinal explants cultured in the presence of different concentrations of glucose. The numbers of regenerating neurites at 3, 6 and 10 days in culture at normal glucose concentration (7 mM) were significantly smaller in streptozotocin-induced diabetic C57BL/6 mice than in normal control mice. In contrast, treatment of retinal explants with high glucose concentration (57 mM) significantly diminished the number of regenerating neurites in the control mice, but not in the diabetic mice. These results suggest that retina in diabetic mice has impaired capability of neurite regeneration in a normal glucose environment, but is adaptable to a high glucose environment in vitro.

Animals↗
PubMed1999

Ultrastructural localization of neuropeptide Y and expression of its mRNA in the glomus cells distributed in the wall of the common carotid artery of the chicken.

In the chicken, glomus cells are widely distributed in the carotid body and in the wall of the common carotid artery and around its branches. The cells located in the wall of the common carotid artery express intense immunoreactivity for neuropeptide Y (NPY). They contain abundant dense-cored vesicles ranging from 70 to 220 nm in diameter. In this study, we examined ultrastructural localization of NPY in the glomus cells by using the postembedding immunogold method. Gold particles representing immunoreactivity for NPY were specifically localized on the dense-cored vesicles of the glomus cells. In addition, the localization of NPY mRNA in the glomus cells was examined by in situ hybridization with digoxigenin-labeled chicken NPY cRNA probe. A strong hybridization signal for NPY mRNA was detected in the glomus cells located in the wall of the common carotid artery. Few glomus cells of the carotid body, however, displayed labeling for NPY mRNA. Northern blot analysis with the chicken NPY exon 4 probe demonstrated that a single band for NPY mRNA was present in the poly (A) + RNA isolated from the common carotid artery where the glomus cells were distributed. Furthermore, the expression of NPY mRNA in the common carotid artery was confirmed by the reverse transcription-polymerase chain reaction. These results indicate that the chicken glomus cells are able to produce NPY but that the level of its translation varies according to the location of the cells.

Animals↗
PubMed1999

Membrane-anchored metalloprotease MDC9 has an alpha-secretase activity responsible for processing the amyloid precursor protein.

MDC9, also known as meltrin gamma, is a membrane-anchored metalloprotease. MDC9 contains several distinct protein domains: a signal sequence followed by a prodomain and a domain showing sequence similarity to snake venom metalloproteases, a disintegrin-like domain, a cysteine-rich region, an epidermal-growth-factor-like repeat, a transmembrane domain and a cytoplasmic domain. Here we demonstrate that MDC9 expressed in COS cells is cleaved between the prodomain and the metalloprotease domain. Further, when MDC9 was co-expressed in COS cells with amyloid precursor protein (APP695) and treated with phorbol ester, APP695 was digested exclusively at the alpha-secretory site in MDC9-expressing cells. When an artificial alpha-secretory site mutant was also co-expressed with MDC9 and treated with phorbol ester, APP secreted by alpha-secretase was not increased in conditional medium. Inhibition of MDC9 by a hydroxamate-based metalloprotease inhibitor, SI-27, enhanced beta-secretase cleavage. These results suggest that MDC9 has an alpha-secretase-like activity and is activated by phorbol ester.

ADAM Proteins↗
PubMed1999

Presenilin 1 suppresses the function of c-Jun homodimers via interaction with QM/Jif-1.

Presenilin 1 (PS1) is the causative gene for an autosomal dominant familial Alzheimer's disease (AD) mapped to chromosome 14. Here we show that QM/Jun-interacting factor (Jif)-1, a negative regulator of c-Jun, is a candidate to mediate the function of PS1 in the cell. We screened for proteins that bind to PS1 from a human embryonic brain cDNA library using the two-hybrid method and isolated one clone encoding the QM/Jif-1 gene. The binding of QM/Jif-1 to full-length PS1 was confirmed in vitro by pull-down assay, and in vivo by immunoprecipitation assays with human samples, including AD brains. Immunoelectronmicroscopic analysis showed that QM/Jif-1 and PS1 are colocalized at the endoplasmic reticulum, and the nuclear matrix in human brain neurons. Chloramphenicol acetyltransferase assays in F9 cells showed that PS1 suppresses transactivation by c-Jun/c-Jun but not by c-Jun/c-Fos heterodimers, consistent with the reported function of QM/Jif-1. By monitoring fluorescent recombinant protein and by gel mobility shift assays, PS1 was shown to accelerate the translocation of QM from the cytoplasm to the nucleus and to thereby suppress the binding of c-Jun homodimer to 12-O-tetradecanoylphorbol-13- acetate (TPA)-responsive element (TRE). PS1 suppressed c-jun-associated apoptosis by retinoic acid in F9 embryonic carcinoma cells, whereas this suppression of apoptosis is attenuated by mutation in PS1. Collectively, the novel function of PS1 via QM/Jif-1 influences c-jun-mediated transcription and apoptosis.

Adult↗
PubMed1999

Direct interaction of the beta-domain of VHL tumor suppressor protein with the regulatory domain of atypical PKC isotypes.

VHL tumor suppressor protein contains two domains, alpha and beta. The alpha-domain is involved in the formation of a large protein complex suggested to be involved in ubiquitin-mediated protein degradation. However, the role of the beta-domain, which may recognize the target proteins for protein degradation, remains unknown. Here we report that the beta-domain interacts directly with atypical PKC isotypes, PKCzeta and PKClambda. Further, the regulatory domain of aPKC is sufficient for this direct protein-protein interaction. Since aPKC isotypes have been implicated in the regulation of cell growth and apoptosis, these results suggest that aPKC isotypes are potential direct target of the VHL beta-domain.

Amino Acid Sequence↗
PubMed1999

Cloning and characterization of the murine PKC alpha promoter: identification of a retinoic acid response element.

Protein kinase C (PKC) is a family which consists of multiple isoforms whose distinct physiological roles within the cell are unknown. We have previously demonstrated that levels of PKC alpha mRNA, protein, and enzyme activity in B16 melanoma cells can be modulated by retinoic acid. We investigated this regulation by cloning and characterizing the promoter region of the murine PKC alpha gene. A 13 kb mouse genomic fragment containing the 5' flanking region, first exon, and first intron was isolated and sequenced. Two transcription initiation sites were identified at 919 and 925 bp upstream from the translation start site. The promoter region contained a TATA-like box at -93 bp upstream of the transcription start site, but no CAAT box. Promoter activity differed between cell lines and correlated with the levels of PKC alpha expressed in these cell lines. Reporter gene assays showed that the region between -179 and -452 bp likely contains a silencer element(s). The promoter activity of a -179 bp fragment in B16 cells was stimulated twofold by retinoic acid. Within this region (-93 to -65 bp) there is a retinoic acid response element. An oligonucleotide spanning this region specifically bound exogenous RAR-RXR heterodimers and endogenous RAR from B16 nuclear extracts. These results suggest that retinoic acid increases PKC alpha gene expression in B16 cells, at least in part, through direct transcriptional stimulation of its promoter.

Animals↗
PubMed1999

RGD-CAP ((beta)ig-h3) enhances the spreading of chondrocytes and fibroblasts via integrin alpha(1)beta(1).

In previous studies, RGD-CAP (collagen-associated protein containing the RGD sequence) isolated from a collagen fiber-rich fraction of pig cartilage was found to be orthologous to human (beta)ig-h3, which is synthesized by lung adenocarcinoma cells in response to transforming growth factor-beta. In the present study, we examined the effect of recombinant chick RGD-CAP on the spreading of chondrocytes and fibroblasts using RGD-CAP-coated dishes. When rabbit articular chondrocytes, chick embryonic sternal chondrocytes, rabbit peritoneal fibroblasts or human MRC5 fibroblasts were seeded on plastic dishes coated with RGD-CAP, cell spreading was enhanced compared with that on control dishes (bovine serum albumin- or beta-galactosidase-coated dishes). The effect of RGD-CAP on the cell spreading required divalent cations (Mg(2+) or Mn(2+)), and was reduced by EDTA. Monoclonal antibodies (mAbs) to the human integrin alpha(1) or beta(1) subunit, but not to the alpha(2), alpha(3), alpha(5) or beta(2) subunits, suppressed the RGD-CAP-induced spreading of human MRC5 fibroblasts. In a parallel experiment, the mAb to the alpha(5) subunit, but not the mAb to the alpha(1) subunit, suppressed fibronectin-induced spreading of these cells. These findings suggest that RGD-CAP is a novel ligand for integrin alpha(1)beta(1) that dose not bind to the RGD motif. Accordingly, an RGD-CAP fragment, which carries a deletion in the C-terminal region containing the RGD motif, was still capable of stimulating cell spreading.

Animals↗
PubMed1999

Intratumoral neovascularization and growth pattern in early gastric carcinoma.

BACKGROUND: The growth pattern of early gastric carcinoma, based on a volumetric analysis, reflects biologic characteristics of the tumor. The authors investigated the microvessel density (MVD), expression of vascular endothelial growth factor (VEGF), and growth patterns in early gastric carcinoma. METHODS: Ninety-four tissue specimens resected from patients with early gastric carcinoma invading the submucosal layer were examined. Microvessel quantification was performed immunohistochemically using a monoclonal antibody against factor VIII-related antigen. VEGF expression was studied using an anti-VEGF polyclonal antibody. Growth patterns were defined as follows: Pen A type: expansively penetrating growth; Pen B type: infiltratively penetrating growth; Super type: superficially spreading growth. RESULTS: The mean MVD was 16.9 (range, 5.2-43.0). MVD was significantly higher in tumors with venous invasion (P<0.01), lymphatic vessel invasion (P<0.05), and lymph node metastases (P<0.05) compared with MVD in tumors without venous or lymphatic vessel invasion or lymph node metastases. The VEGF-positive rate of Pen A type tumors was 66.7% (18 of 27), that Pen B type was 10.0% (1 of 10), that of Super type was 19.4% (6 of 31), and that of the unclassified type was 15.4% (4 of 26). The VEGF-positive rate in patients with Pen A type tumors was significantly higher than that in patients with the other three growth patterns(P<0.01). MVD in patients with Pen A type tumors (25.9+/-9.2) was significantly higher than that in patients with Super type tumors (12.6+/-5.4) (P<0.01). Patients with Pen A type tumors had a poorer prognosis than patients whose tumors had other growth patterns (P<0.05). According to multivariate analysis, VEGF expression and lymphatic vessel invasion were significant prognostic factors. CONCLUSIONS: Pen A type gastric carcinoma tends to secrete VEGF, thus inducing tumor angiogenesis and resulting in venous invasion. Intensive follow-up is necessary for patients with Pen A type tumors, because this tumor type has a greater propensity for hematogenous metastasis.

Aged↗
PubMed1999

Enhancement of cell adhesion and spreading by a cartilage-specific noncollagenous protein, cartilage matrix protein (CMP/Matrilin-1), via integrin alpha1beta1.

Cartilage matrix protein (CMP; also known as matrilin-1), one of the major noncollagenous proteins in most cartilages, binds to aggrecan and type II collagen. We examined the effect of CMP on the adhesion of chondrocytes and fibroblasts using CMP-coated dishes. The CMP coating at 10-20 micrograms/ml enhanced the adhesion and spreading of rabbit growth plate, resting and articular chondrocytes, and fibroblasts and human epiphyseal chondrocytes and MRC5 fibroblasts. The effect of CMP on the spreading of chondrocytes was synergistically increased by native, but not heated, type II collagen (gelatin). The monoclonal antibody to integrin alpha1 or beta1 abolished CMP-induced cell adhesion and spreading, whereas the antibody to integrin alpha2, alpha3, alpha5, beta2, alpha5beta1, or alphaVbeta5 had little effect on cell adhesion or spreading. The antibody to integrin alpha1, but not to other subunits, coprecipitated 125I-CMP that was added to MRC5 cell lysates, indicating the association of CMP with the integrin alpha1 subunit. Unlabeled CMP competed for the binding to integrin alpha1 with 125I-CMP. These findings suggest that CMP is a potent adhesion factor for chondrocytes, particularly in the presence of type II collagen, and that integrin alpha1beta1 is involved in CMP-mediated cell adhesion and spreading. Since CMP is expressed almost exclusively in cartilage, this adhesion factor, unlike fibronectin or laminin, may play a special role in the development and remodeling of cartilage.

Animals↗
PubMed1999

Protein kinase C regulates integrin-induced activation of the extracellular regulated kinase pathway upstream of Shc.

Adhesion of fibroblasts to extracellular matrices via integrin receptors is accompanied by extensive cytoskeletal rearrangements and intracellular signaling events. The protein kinase C (PKC) family of serine/threonine kinases has been implicated in several integrin-mediated events including focal adhesion formation, cell spreading, cell migration, and cytoskeletal rearrangements. However, the mechanism by which PKC regulates integrin function is not known. To characterize the role of PKC family kinases in mediating integrin-induced signaling, we monitored the effects of PKC inhibition on fibronectin-induced signaling events in Cos7 cells using pharmacological and genetic approaches. We found that inhibition of classical and novel isoforms of PKC by down-regulation with 12-0-tetradeconoyl-phorbol-13-acetate or overexpression of dominant-negative mutants of PKC significantly reduced extracellular regulated kinase 2 (Erk2) activation by fibronectin receptors in Cos7 cells. Furthermore, overexpression of constitutively active PKCalpha, PKCdelta, or PKCepsilon was sufficient to rescue 12-0-tetradeconoyl-phorbol-13-acetate-mediated down-regulation of Erk2 activation, and all three of these PKC isoforms were activated following adhesion. PKC was required for maximal activation of mitogen-activated kinase kinase 1, Raf-1, and Ras, tyrosine phosphorylation of Shc, and Shc association with Grb2. PKC inhibition does not appear to have a generalized effect on integrin signaling, because it does not block integrin-induced focal adhesion kinase or paxillin tyrosine phosphorylation. These results indicate that PKC activity enhances Erk2 activation in response to fibronectin by stimulating the Erk/mitogen-activated protein kinase pathway at an early step upstream of Shc.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Administration of an IL-12-encoding DNA plasmid prevents the development of chronic graft-versus-host disease (GVHD).

The transfer of DBA/2 spleen cells into (C57BL/10 x DBA/2)F1 mice induces chronic graft-vs-host disease (GVHD), which is characterized by the production of Th2 cytokines, hypergammaglobulinemia, and immune complex-mediated glomerulonephritis like systemic lupus erythematosus. IL-12 strongly induces the production of Th1 cytokines and reduces Th2 activity in vivo. In this study, the effect of gene therapy on the development of murine chronic GVHD was examined using an IL-12-encoding plasmid (pCAGGSIL-12), with the expectation that it might regulate Th1/Th2 activity and have a beneficial impact on the clinical manifestations of disease. pCAGGSIL-12 or its p40 antagonist plasmid (pCAGGSp40) were injected i.m. every 3 wk in GVHD-induced (C57BL/10 x DBA/2)F1 mice. A total of 100 microg of pCAGGSIL-12 improved the Th1/Th2 balance in vivo, suppressed the production of IgG, and significantly reduced the development of glomerulonephritis. GVHD was exacerbated by injection of the pCAGGSp40 antagonist. Our results demonstrate that GVHD can be treated successfully by the administration of an IL-12-encoding plasmid, and that such therapy does not induce acute GVHD.

Animals↗
PubMed1999

Human hepatitis B virus X protein is detectable in nuclei of transfected cells, and is active for transactivation.

Subcellular localization and transactivation of human hepatitis B virus X protein (HBx), a plausible causative factor for hepatocellular carcinogenesis, were studied in transiently transfected cells. The transactivation was detected not only by the cis-element driven chloramphenicol acetyltransferase (CAT) assay but also by immunostaining of CAT protein cotransfected into human hepatoma cell line HepG2. Scanning fluorescence microscopy showed the majority of immunological signals of HBx to be at the perinuclear region of transfected cytoplasm. HBx was also clearly detectable in the nucleus, though less intensely expressed. This was confirmed by Western analysis and coimmunoprecipitation of HBx with transcription factor IIB (TFIIB) in subcellular fractionations. The percentage of HBx-positive cells coincided with that of CAT-positive cells, and confocal laser microscopy revealed the coexistence of CAT signals in GFP-HBx positive cells. The SV40 large T antigen nuclear localization signal (NLS) appended HBx, regardless of whether NLS was added to the N- or C-terminus, transactivated all the examined X-responsive elements (XRE) similarly as did wild-type HBx. Similar results were obtained in p53 negative Saos-2 cells. The detected nuclear HBx may be involved in modulating the transcription at the promoter level whereas the HBx in cytoplasm may be working through signal transduction pathways.

Cell Nucleus↗