Biomedical subjects

Mine Harada

Publications and source records attributed to Mine Harada.

At least 127 records · Page 7Linked to original sources

PubMed2003

High-density lipoprotein binding rate differs greatly between genotypes 1b and 2a/2b of hepatitis C virus.

The hepatitis C virus (HCV) virion is associated with lipoproteins and immunoglobulins in the sera of patients with chronic hepatitis C; however, an accurate binding rate of HCV to lipoproteins or immunoglobulins has not yet been elucidated. Therefore, the accurate binding rate of HCV to low-density lipoproteins (LDL), high-density lipoproteins (HDL), and immunoglobulins was measured quantitatively by a real-time PCR assay. The immunoglobulin binding rate of HCV was found to be greater than 97.5% in most patients, as compared with an LDL binding rate of greater than 80% in most patients. In contrast, the HDL binding rate was greater than 98% in the genotype 2a/2b patients, while it varied in the genotype 1b patients. The genotype 2a/2b HCV not only had a higher LDL binding rate but also had a strikingly higher HDL binding rate than that of the genotype 1b HCV. These lipoprotein binding rates correlated neither to any patient's variables, including the serum apolipoprotein levels, nor to the viral load or the hypervariable region 1 (HVR 1) amino acid sequences. Most of the HCV virions in the sera of such patients have been shown to be associated simultaneously with immunoglobulins and LDL and/or HDL, but not exclusively.

Amino Acid Sequence↗

PubMed2003

Dynamics of Epstein-Barr virus load in pyothorax-associated lymphoma.

We treated a 73-year-old man who developed a pyothorax-associated pleural lymphoma after a 52-year history of tuberculous pleuritis. The lymphoma was classified histologically as a diffuse large, B-cell type. Epstein-Barr virus (EBV) was identified in the tumor by immunocytochemical and molecular methods. Chemotherapy both without and with the addition of rituximab was only minimally effective, but adding radiotherapy to chemotherapy reduced the tumor size, resulting in a partial remission. The EBV load measured by a quantitative real-time polymerase chain reaction correlated well with the tumor size and the serum lactate dehydrogenase concentration. Monitoring the EBV load may be useful in the management of pyothorax-associated lymphoma.

Empyema, Pleural↗

PubMed2003

Chronic graft-versus-host disease following varicella-zoster virus infection in allogeneic stem cell transplant recipients.

We describe 2 allogeneic stem cell transplantation patients who developed chronic graft-versus-host disease (GVHD) after dermatomal varicella-zoster virus (VZV) infection. Localized zoster did not respond to oral valaciclovir but did resolve with intravenous aciclovir. However, skin eruptions, eye/oral dryness, and liver dysfunction were observed at the healing stage of localized zoster, suggesting development of GVHD. Intensification of immunosuppressive therapy was required to control GVHD. Quantitative real-time PCR for VZV DNA was used to distinguish liver involvement by chronic GVHD from visceral dissemination of VZV in 1 patient. VZV infection may trigger chronic GVHD after allogeneic stem cell transplantation.

Chickenpox↗

PubMed2003

Limitin, an interferon-like cytokine, transduces inhibitory signals on B-cell growth through activation of Tyk2, but not Stat1, followed by induction and nuclear translocation of Daxx.

OBJECTIVE: Limitin, an interferon-like cytokine, suppresses B lymphopoiesis through ligation of the interferon-alpha/beta (IFN-alpha/beta) receptor. The aim of this study was to examine the intracellular signal transduction pathways activated by limitin. MATERIALS AND METHODS: The effects of limitin on cell growth, the activation of Jak kinase and Stat proteins, and the induction of interferon regulatory factor-1 (IRF-1) and Daxx were examined using the mouse pre-B-cell line 18.81, wild-type, and Tyk2-deficient mouse bone marrow cells. In addition, the change of localization of the Daxx protein after limitin treatment in wild-type and Tyk2-deficient mice was examined. RESULTS: Limitin phosphorylates Tyk2, Jak1, Stat1, and Stat2 and rapidly induces IRF-1 mRNA production. Phosphorylation of Stat1 by limitin is partially dependent on Tyk2. Suppression of B-cell growth by limitin, however, is severely impaired in the absence of Tyk2, whereas it is unaffected by the absence of Stat1. Limitin also induces the expression and nuclear translocation of Daxx, which is essential for IFN-alpha-induced inhibition of B-lymphocyte development. The absence of Tyk2 abrogates this induction of Daxx expression and nuclear translocation. CONCLUSIONS: Limitin suppresses B-cell growth through activation of Tyk2, resulting in the up-regulation and nuclear translocation of Daxx. This limitin-mediated signaling pathway does not require Stat1.

Active Transport, Cell Nucleus↗

PubMed2003

Distinct costimulation dependent and independent autoreactive T-cell clones in primary biliary cirrhosis.

BACKGROUND & AIMS: Previous work has suggested that CD4+ CD28- or costimulation-independent T cells are increased in autoimmune diseases. In this study, we compared frequency and qualitative characteristics of autoreactive costimulation-independent or CD4+ CD28- T cells in primary biliary cirrhosis (PBC) by taking advantage of the well-defined immunodominant autoepitope of the E2 component of pyruvate dehydrogenase (PDC-E2). METHODS: We determined the frequency of costimulation-independent autoreactive T cells that respond to PDC-E2 163-176 and the frequency of CD4+ CD28- T cells. Finally, we determined the role of biliary epithelial cells (BEC) as both an antigen-presenting cell or, alternatively, as a target cell for T-cell-mediated cytotoxicity. RESULTS: The precursor frequency of costimulation-independent CD4+ T cells that respond to PDC-E2 163-176 and the frequency of CD4+ CD28- T cells were dramatically elevated in PBC. Furthermore, 2 types of T-cell clones that respond to PDC-E2 163-176 emerged from this study. One type was costimulation dependent and the other costimulation independent. Both types of clones lyse BEC in a similar effector target (E/T) ratio distribution. However, BEC did not help the proliferation of any T-cell clones. Furthermore, costimulation-independent T-cell clones do not become anergic by BEC. CONCLUSIONS: In PBC, costimulation-independent autoreactive T cells, which do not become anergic, increase and maintain the autoimmune response. In controls, although autoantigens are expressed on BEC and autoantigen-reactive T cells exist around BEC, autoantigen-reactive T cells are costimulation dependent and will become anergic and maintain peripheral tolerance.

Antigen-Presenting Cells↗

PubMed2003

Molecular mimicry of mitochondrial and nuclear autoantigens in primary biliary cirrhosis.

BACKGROUND & AIMS: The mechanism for development of primary biliary cirrhosis (PBC) remains enigmatic, but molecular mimicry has been implicated because of well-known cross-reactivity of human mitochondrial autoantigens and equivalent bacterial antigens. Virtually all patients with PBC have antimitochondrial autoantibodies (AMA), but, interestingly, approximately 50% also manifest antinuclear antibodies (ANA). METHODS: To determine whether generation of ANA are due to molecular mimicry of mitochondrial peptides, we established 6 T-cell clones selected by a peptide corresponding to the E2 subunit of mitochondrial pyruvate dehydrogenase complex and analyzed for reactivity to mimicry peptides derived from mitochondrial and nuclear autoantigens, including control sequences. RESULTS: For mitochondrial autoantigens, 1 peptide from the E2 subunit of the pyruvate dehydrogenase complex, 1 peptide from the E2 subunit of the oxo-glutarate dehydrogenase complex, 1 peptide from the E2 subunit of the branched-chain 2-oxoacid dehydrogenase complex, and 1 peptide from the E3-binding protein cross-reacted with these T-cell clones. For the nuclear autoantigens, 5 peptides from gp210 and 1 from Sp100 cross-reacted with these clones. Furthermore, 1 of 3 T-cell clones selected by recombinant gp210 protein reacted with a mimicry peptide corresponding to amino acids 188-201 of gp210, indicating that this part of the protein is a naturally processed immunodominant T-cell epitope. CONCLUSIONS: These results demonstrate molecular mimicry between mitochondrial and nuclear autoantigens in PBC and that a mimicry peptide may become an immunodominant T-cell epitope. These data have significance not only for PBC but also for the production of ANA in other disease processes.

Amino Acid Sequence↗

PubMed2003

Phase I/II study of altered schedule of cisplatin and etoposide administration and concurrent accelerated hyperfractionated thoracic radiotherapy for limited-stage small-cell lung cancer.

To improve the efficacy of a combination of cisplatin and etoposide and concurrent accelerated twice-daily thoracic radiotherapy against limited-stage small-cell lung cancer, we conducted a phase I/II study using an altered schedule of chemotherapy administration. Chemotherapy consisted of four cycles of cisplatin (days 1 and 8) and etoposide (days 1, 2, 8, and 9) every 4 weeks. Accelerated hyperfractionated thoracic radiation (1.5 Gy twice daily x 30 fractions, total dose of 45 Gy) was concurrently given with the first cycle of chemotherapy. The recommended doses of cisplatin and etoposide determined in the phase I study were 40 and 80 mg/m(2), respectively. In the phase II study, the overall response rate was 100% (complete response: 32%, partial response: 68%). By a median follow-up time of 29 months, median radiation-outfield progression-free survival was 13.4 months, while radiation-infield progression-free survival did not reach median value. The median overall survival time was 22.9 months, with survival rate of 48.4% at 2 years. Major toxicities were leukopenia and neutropenia (>/=grade 3, 92% each). The local control and overall survival demonstrated in this study were excellent. However, the insufficient distant control suggests a need for development of more active chemotherapy regimens.

Aged↗

PubMed2003

Promiscuous T cells selected by Escherichia coli: OGDC-E2 in primary biliary cirrhosis.

The etiology of primary biliary cirrhosis (PBC) remains enigmatic. One theory that has attracted attention proposes that PBC is induced via molecular mimicry with Escherichia coli. If molecular mimicry is responsible for the immunogenic response in PBC, then T cell clones specific for E. coli antigens should stimulate and be cross-reactive with peptides specific for the human immunodominant autoepitopes. To address this issue, we developed T cell clones specific for E. coli OGDC-E2 peptide. Importantly, we demonstrate the presence of T cell clones specific for E. coli OGDC-E2 that react promiscuously with the human mitochondrial equivalents. Indeed, there was a significant increase in the liver derived T cell precursor frequency of such reactivity and such liver clones were only found in patients with PBC. In conclusion, these data suggest that PBC is a multi-hit disease involving a genetic predisposition, a mucosal response, and activation of promiscuous T cells; such activation may occur either directly from bacterial antigens, or indirectly through chemically-modified bacterial antigens. Dissection of the mechanisms involved will lead not only to understanding the immunogenetic basis of PBC, but likely its pathogenic etiology.

Acyltransferases↗

PubMed2003

Bezold-Jarisch-like reflex during Brockenbrough's procedure for radiofrequency catheter ablation of focal left atrial fibrillation: report of two cases.

Brockenbrough's puncture technique has been widely conducted in the electrophysiologic laboratory. We report here two cases exhibiting a rare complication of this procedure, which arose during the conduct of catheter ablation using radiofrequency energy delivered to the pulmonary vein for the treatment of focal left atrial fibrillation. These cases exhibited marked sinus bradycardia and profound hypotension, suggestive of a Bezold-Jarisch-like reflex, observed immediately after Brockenbrough's procedure but before radiofrequency application. ST elevation in the inferior leads was also observed in spite of normal coronary angiograms. This unanticipated transient complication was treated by intravenous administration of atropine, which had no influence on the ablation procedure or prognosis. This is speculated to be attributable to the elevation of vagal tone caused by the mechanical effects of transseptal puncture on the interatrial vagal network.

Adult↗

PubMed2003

The lipocalin 24p3, which is an essential molecule in IL-3 withdrawal-induced apoptosis, is not involved in the G-CSF withdrawal-induced apoptosis.

Many hematopoietic cells undergo apoptosis when deprived of specific cytokines. Lipocalin 24p3, reported to be induced in hematopoietic cells by interleukin 3 (IL-3) depletion, induces hematopoietic cell apoptosis despite the presence of IL-3. As granulocyte colony stimulating factor (G-CSF) depletion also induces the apoptosis of G-CSF-dependent cell line cells, we examined the effect of 24p3 on the apoptotic function induced by G-CSF depletion. 24p3 was induced by the depletion of IL-3, but not G-CSF, in cytokine-dependent cell lines. Although 24p3 suppressed growth induced by IL-3, it did not influence G-CSF-dependent cell growth. These observations show that 24p3 is not involved in the G-CSF withdrawal-induced apoptosis, although it is essential in IL-3 withdrawal-induced apoptosis.

Acute-Phase Proteins↗

PubMed2003

Detection of human herpesvirus-8 in peripheral blood mononuclear cells from adult Japanese patients with multicentric Castleman's disease.

Human herpesvirus-8 (HHV-8) encodes viral homologues of cellular genes, including viral interleukin 6 (vIL-6), which induces endogenous human IL-6 (hIL-6) secretion. Unregulated overproduction of hIL-6 in lymph nodes (LN) is thought to be responsible for the systemic manifestations of multicentric Castleman's disease (MCD). In the present study, we assessed the presence of HHV-8 and HHV-8-encoded viral homologues in LN and peripheral blood mononuclear cells (PBMC) from adult Japanese patients with MCD. HHV-8 DNA was amplified by nested polymerase chain reaction (PCR) and was detected in LN from 13 out of 16 MCD patients (81%). HHV-8 DNA was also detected in PBMC from six out of seven patients (86%) whose LN were positive for HHV-8 DNA. Because mRNA could not be successfully extracted from LN sections that were either formalin-fixed or embedded in paraffin, we examined the expression of mRNA for HHV-8-encoded viral homologues, such as vIL-6, vBCL-2, vCyclin-D and viral G-protein-coupled receptor (vGPCR) by nested reverse transcription (RT)-PCR in PBMC from 10 MCD patients. However, mRNA of these HHV-8-encoded viral homologues was not detected in any patients tested. Although our results do not indicate a role for HHV-8-encoded viral homologues in the pathogenesis of MCD, they do suggest that HHV-8 infection may be associated with MCD in adult Japanese patients.

Adult↗

PubMed2003

Over-expression of short isoforms of Helios in patients with adult T-cell leukaemia/lymphoma.

In previous studies, we demonstrated an over-expression of the dominant-negative isoform of the transcription factor Ikaros in patients with blast crisis of both chronic myelogenous leukaemia and B-cell acute lymphoblastic leukaemia (ALL). Recently, we reported an over-expression of the short isoforms of Helios, which is one of the members of the Ikaros gene family, in a patient with T-cell ALL. In the present study, we found over-expression of short isoforms of Helios in human T lymphotropic virus-I (HTLV1)-infected patients who had developed chronic and acute forms of adult T-cell leukaemia/lymphoma. In contrast, we could not detect any over-expression of short isoforms of Helios in healthy HTLV1 carriers. By Southern blotting, we detected a small deletion in the Helios gene locus of adult T-cell leukaemia/lymphoma patients. The present results suggest that Helios gene abnormalities might be one of the important mechanisms in the disease progression of HTLV1 infection.

Blotting, Southern↗

PubMed2003

Over-expression of the dominant-negative isoform of Ikaros confers resistance to dexamethasone-induced and anti-IgM-induced apoptosis.

In previous studies, we demonstrated an over-expression of the dominant-negative isoform of the transcription factor Ikaros, Ik-6, in patients with B-cell malignancies, including blast crisis of chronic myelogenous leukaemia and acute lymphoblastic leukaemia. To investigate the consequence of over-expression of Ik-6 in B cells, we constructed Ik-6 transfectants of the FDH-1 and Ramos cell lines. FDH-1, which was established from a patient with early pre-B acute lymphoblastic leukaemia, undergoes apoptosis with dexamethasone treatment, whereas Ramos undergoes apoptosis following anti-IgM antibody treatment. Compared with the wild type, the over-expression of Ik-6 rendered the FDH-1 and Ramos transfectants resistant to dexamethasone-induced and anti-IgM-induced apoptosis respectively. An immunoblotting study demonstrated bcl-2 upregulation in anti-IgM-induced Ramos Ik-6 transfectants, but not in FDH-1 Ik-6 transfectants. Further investigations of the mechanism of leukaemogenesis associated with the over-expression of Ik-6 are warranted.

Analysis of Variance↗

PubMed2003

The type 1 CD10/neutral endopeptidase 24.11 promoter: functional characterization of the 5'-untranslated region.

The cell surface zinc metalloproteinase CD10/neutral endopeptidase 24.11 (NEP) is expressed on normal and malignant lymphoid progenitors, granulocytes and a variety of epithelial cells. Because CD10/NEP functions as part of a regulatory loop that controls local concentrations of peptide substrates and associated peptide-mediated signal transduction, its role in each tissue is different depending on the availability of substrate. To characterize further how this widely distributed molecule is regulated differentially in each tissue, we analysed the major type 2 CD10/NEP promoter and found three functionally important transcription factor binding sites, one of which was identical to CCAAT-binding transcription factor/nuclear transcription factor Y. In this report, we analyse the type 1 CD10/NEP promoter and found a functionally important transcription factor binding site in the 5'-untranslated region. The results of the competition and supershift experiments demonstrated that the functionally important transcription factor was identical to Sp1. Our results suggest that ubiquitously expressed Sp1 may play an important role in differentiation stage-specific regulation of CD10/NEP expression in lymphoid lineage.

5' Untranslated Regions↗

PubMed2003

Intracellular signal transduction of interferon on the suppression of haematopoietic progenitor cell growth.

Interferon (IFN)-alpha and IFN-gamma suppress the growth of haematopoietic progenitor cells. IFN-alpha activates Janus kinase-1 (Jak1) and Tyrosine kinase-2 (Tyk2), followed by the phosphorylation of the signal transducers and activators of transcription, Stat1 and Stat2. IFN-gamma activates Jak1 and Jak2, followed by the activation of Stat1. Activated Stats bind the promoter regions of IFN-inducible genes. We evaluated the role of Tyk2 and Stat1 in the IFN-mediated inhibition of haematopoietic progenitor cell growth. While IFN-alpha (1000 U/ml) suppressed the number of granulocyte-macrophage colony-forming units (CFU-GM) or erythroid burst-forming units (BFU-E) from wild-type mouse bone marrow cells, this suppression was partially inhibited by a deficiency in Tyk2 and completely inhibited by a deficiency in Stat1. High levels of IFN-alpha (10,000 U/ml) suppressed the CFU-GM or BFU-E obtained from Stat1-deficient mice, but did not suppress this growth in cells from Tyk2-deficient mice. Stat1 was phosphorylated by IFN-alpha in Tyk2-deficient cells, although the level of phosphorylation was weaker than that observed in wild type mice. Thus, the inhibitory signal on haematopoietic progenitor cells mediated by IFN-alpha may be transduced by two signalling pathways, one regulated by Tyk2 and the other dependent on Stat1. IFN-gamma also suppressed the number of CFU-GM or BFU-E, and this pathway was mediated by IFN-gamma in a Stat1-dependent manner, independently of Tyk2.

Animals↗

PubMed2003

Non-B, non-T neoplasms with lymphoblast morphology: further clarification and classification.

We studied the morphologic, immunohistochemical, and clinical characteristics of 158 cases of lymphoblastic lymphoma. Based on immunophenotyping and cell lineage, cases were classified into B-cell type (CD20,CD19 or CD79a+, n = 53), T-cell type (surface CD3+, n = 84), and non-B, non-T type (B cell marker- and surface CD3-, n = 21). The latter group was further divided based on immunohistochemistry into: 1) CD7+ stem cell lymphoma (CD7+SCL) [CD4-, CD7+, CD33+/-, CD56-], 2) blastic natural killer cell lymphoma (B-NKL) [CD4-, CD7+/-, CD33-, CD56+, CD123-], 3) myeloid/NK precursor cell leukemia (M/NKL) [CD4-, CD7+, CD33+, CD56+], and 4) CD4+CD56+ hematodermic malignancy (CD4+CD56+) type [CD4+, CD7+/-, CD33-, CD56+, CD123+]. The CD7+SCL and M/NKL types frequently exhibited bone marrow invasion and mediastinal masses. All CD4+CD56+ types were associated with skin lesions. B-NKL type is included into Blastic NK lymphoma in new World Health Organization classification with CD4+CD56+ type. But the cases of B-NKL were more reminiscent of CD7+SCL or M/NKL type than the CD4+CD56+ type, both clinically and histologically. We propose that blastic NK lymphoma, a disease entity in the new WHO classification, should be divided into two types based on phenotypes and clinical features. The non-B, non-T lymphomas exhibited poorer prognoses, similar to that of B-cell lymphomas, than T-cell type tumors (P = 0.009). Among the 21 tumors, the prognosis of the four subtypes did not differ significantly; however, cases receiving aggressive chemotherapy and stem cell transplantation had a more favorable prognosis than those receiving only traditional chemotherapy and radiation therapy (P = 0.0089).

Adolescent↗

PubMed2003

Transplanted human cord blood cells give rise to hepatocytes in engrafted mice.

Recent studies suggest that rodent hepatocytes may be derived from hematopoietic stem cells. In the current study, the potential hematopoietic origin of hepatocytes was addressed using xenogeneic transplantation of human cord blood cells. CD34(+) or CD45(+) human cord blood cells were transplanted into "conditioned" newborn NOD/SCID/beta2-microglobulin(null) mice. At 4 to 5 months post-transplantation, livers of the recipient mice were cryosectioned and examined for evidence of human hepatocyte engraftment using RT-PCR to detect human albumin mRNA, immunohistochemistry to detect human hepatocytic proteins, and fluorescence in situ hybridization (FISH) to detect the presence of human centromeric DNA. Analysis of the bone marrow of transplanted mice revealed that 21.0-45.9% of the cells were human CD45(+) cells. FISH analysis of frozen sections of transplanted mouse liver revealed the presence of engrafted cells positive for human centromeric DNA. That engrafted human cells functioned as hepatocytes was indicated by the expression of human albumin mRNA, as judged by RT-PCR. FISH analysis with human and mouse centromeric DNA probes excluded spontaneous cell fusion as the cause for the generation of human hepatocytes. Human cord blood cells can give rise to hepatocytes in a xenogeneic transplantation model. This model will be useful to further characterize the cord blood progenitors of hepatocytes.

Animals↗

PubMed2003

The iron-binding protein Dps confers hydrogen peroxide stress resistance to Campylobacter jejuni.

We identified and characterized the iron-binding protein Dps from Campylobacter jejuni. Electron microscopic analysis of this protein revealed a spherical structure of 8.5 nm in diameter, with an electron-dense core similar to those of other proteins of the Dps (DNA-binding protein from starved cells) family. Cloning and sequencing of the Dps-encoding gene (dps) revealed that a 450-bp open reading frame (ORF) encoded a protein of 150 amino acids with a calculated molecular mass of 17,332 Da. Amino acid sequence comparison indicated a high similarity between C. jejuni Dps and other Dps family proteins. In C. jejuni Dps, there are iron-binding motifs, as reported in other Dps family proteins. C. jejuni Dps bound up to 40 atoms of iron per monomer, whereas it did not appear to bind DNA. An isogenic dps-deficient mutant was more vulnerable to hydrogen peroxide than its parental strain, as judged by growth inhibition tests. The iron chelator Desferal restored the resistance of the Dps-deficient mutant to hydrogen peroxide, suggesting that this iron-binding protein prevented generation of hydroxyl radicals via the Fenton reaction. Dps was constitutively expressed during both exponential and stationary phase, and no induction was observed when the cells were exposed to H(2)O(2) or grown under iron-supplemented or iron-restricted conditions. On the basis of these data, we propose that this iron-binding protein in C. jejuni plays an important role in protection against hydrogen peroxide stress by sequestering intracellular free iron and is expressed constitutively to cope with the harmful effect of hydrogen peroxide stress on this microaerophilic organism without delay.

Bacterial Proteins↗