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Biomedical subjects

M Harada

Publications and source records attributed to M Harada.

At least 343 records · Page 19Linked to original sources
PubMed1998

Urocortin, a newly identified corticotropin-releasing factor-related mammalian peptide, stimulates atrial natriuretic peptide and brain natriuretic peptide secretions from neonatal rat cardiomyocytes.

The effect of urocortin (UCN), a recently characterized mammalian member of corticotropin-releasing factor (CRF)-related peptide and a putative endogenous ligand for CRF type 2 beta receptor in the regulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release, was investigated using cultured neonatal rat cardiomyocytes. Treatment with UCN (10(-10)-10(-6)M) resulted in significant increase in ANP and BNP secretions, and the effect of UCN on ANP and BNP secretions was more potent than that of CRF on an equimolar basis. The effect of UCN (10(-7)M) was completely blocked by alpha-helical CRF (9-41), a specific CRF type 2 receptor antagonist. The effect of UCN (10(-7)M) was not only blunted by cAMP-dependent protein kinase A (PKA) inhibitor, H-89 (10(-5)M), but also diltiazem (10(-7)M), a voltage-dependent Ca2+ channel blocker. Further, UCN stimulated cAMP production in cardiomyocytes. Also, UCN (10(-7)M) itself stimulated [3H]leucine uptake into neonatal rat cardiomyocytes and potentiated endothelin-1-induced increase of [3H]leucine uptake. These results suggest that activation of CRF type 2 receptor, especially type 2 beta receptor, with UCN induces ANP and BNP secretions, at least in part, via PKA pathway during cardiac hypertrophy.

Animals↗
PubMed1998

Characterization of a novel human natural killer-cell line (NK-YS) established from natural killer cell lymphoma/leukemia associated with Epstein-Barr virus infection.

A novel cell line was established from a patient with a leukemic-state nasal angiocentric natural killer (NK) cell lymphoma with systemic skin infiltration. The morphology of the leukemic cells was large-granular-lymphocyte (LGL), and their immunophenotype was CD2+, CD3-, CD5+, CD7+, CD16-, CD56+, and CD57-. The presence of Epstein-Barr viral (EBV) genome was shown in specimens from the patient's nose, skin, and peripheral blood by in situ hybridization using an EBV-encoded small RNA-1 probe or by Southern blotting using a terminal-repeat probe of the EBV genome. Leukemic cells were cocultured with a mouse stromal cell line (SPY3-2) in the presence of 100 U/mL recombinant human interleukin-2 and a novel stromal cell-independent cell line, NK-YS, was established. The NK-YS cells showed LGL morphology and expressed surface CD2, CD5, CD7, CD25, CD56, and CD95. The NK-YS cells retained cytotoxicity against K562 and Jurkat cells. A Southern blotting using a terminal-repeat probe of EBV showed that NK-YS and fresh leukemic cells had a clonal EBV genome, whereas the T-cell receptor beta and gamma chain genes of NK-YS were not rearranged. In an immunocytochemical analysis, the NK-YS cells showed a type-II latent infection of EBV. The NK-YS cells preserved the original characteristics of NK cell lymphoma/leukemia and will be a useful tool for the study of biological characteristics of EBV-associated nasal angiocentric NK cell lymphoma/leukemia.

Adult↗
PubMed1998

IL-4-producing NK1.1+ T cells are resistant to glucocorticoid-induced apoptosis: implications for the Th1/Th2 balance.

To elucidate the mechanisms by which glucocorticoids promote Th2-type responses, we investigated the influence of dexamethasone (DEX) on both cytokine production and viability of NK1.1+ T cells. The in vivo administration of DEX enhanced the IL-4 production of spleen cells and liver mononuclear cells in wild-type mice, but not in beta2m-deficient mice. DEX reduced the cellularity of conventional T cells, but not that of NK1.1+ T cells, in both spleen and liver, suggesting an increased proportion of NK1.1+ T cells. Moreover, the proportion of IL-4-producing NK.1 + T cells increased in the DEX-injected mice. These results suggest that DEX induced IL-4 production through the preferential survival of IL-4-producing NKI.1+ T cells. In investigating the reason for the preferential survival of NK1.1+ T cells, we found that NK1.1+ T cells were resistant to DEX-induced apoptosis and expressed a higher level of intracellular Bcl-2 compared with conventional NKI.1- T cells. In addition, splenic and hepatic NK1.1+ T cells were resistant to radiation-induced apoptosis. Collectively, our findings revealed an important role for NK1.1+ T cells in the regulation of Th1/Th2 balance by glucocorticoids and their possible functions under various apoptotic stimuli.

Animals↗
PubMed1998

A randomized trial of hybrid administration of cyclophosphamide, doxorubicin, and vincristine (CAV)/cisplatin and etoposide (PVP) versus sequential administration of CAV-PVP for the treatment of patients with small cell lung carcinoma: results of long term follow-up.

BACKGROUND: In an attempt to determine the efficacy of cyclophosphamide, doxorubicin, and vincristine (CAV)/cisplatin and etoposide (PVP) hybrid chemotherapy (HYB), a rapidly alternating chemotherapy, in patients with small cell lung carcinoma (SCLC), the authors conducted a randomized study to compare HYB with CAV-PVP sequential chemotherapy (SEQ). METHODS: Patients in the HYB group received the 3-drug CAV combination on Day 1 and the 2-drug PVP combination on Day 8, repeated every 4 weeks for up to 6 cycles. Patients in the SEQ group received 3 cycles each of CAV and PVP sequentially every 4 weeks, delivered on Days 1 and 8. All responding patients with limited disease (LD) received thoracic irradiation (50 gray) after chemotherapy. RESULTS: Between April 1988 and October 1992, 129 patients were evaluated fully. There were no significant differences in the treatment outcome between patients in the HYB and SEQ groups in terms of the complete response rate (59% for LD patients and 21% for extensive disease [ED] patients in the HYB group vs. 45% for LD patients and 16% for ED patients in the SEQ group), or median survival time (17.9 months for LD patients and 9.7 months for ED patients in the HYB group vs. 20.6 months for LD patients and 12.2 months for ED patients in the SEQ group). CONCLUSIONS: Hybrid CAV-PVP therapy is effective for the treatment of SCLC, but appears to be no better than sequential therapy with the same regimen.

Adult↗
PubMed1998

Role of the endogenous production of interleukin 12 in immunotherapy.

Previous studies demonstrated that injecting mice with the cytokine interleukin 12 (IL-12) could significantly suppress the growth of a number of tumors, including murine B16 melanoma. In this report, the persistence of the antitumor effects of IL-12 is investigated. The i.p. injection of IL-12 (0.1 microg) on days 14, 16, 18, 20, and 22 was found to significantly suppress the growth of s.c. inoculated B16 melanoma for up to 2 weeks after the last injection of IL-12. Interestingly, the IL-12 serum level 4 days after the last injection of IL-12 was significantly elevated in tumor-bearing mice compared with that of IL-12-treated normal mice. The in vivo depletion of either CD4+ or CD8+ T cells abrogated the antitumor activity of IL-12 and diminished the apparent autocrine stimulation of IL-12 release seen after IL-12 treatment. Resection of the tumor-draining lymph nodes (LNs) but not of the spleen abrogated the antitumor effect of IL-12 treatment as well as the elevation of serum IL-12. Expression of mRNA encoding IL-12 as well as CD40 ligand (CD40L) was detected in the tumor-draining LNs but not in the spleen of tumor-bearing mice after IL-12 treatment. Furthermore, the antitumor activity observed after IL-12 treatment was diminished by the in vivo administration of either anti-IL-12 or anti-CD40L monoclonal antibodies. Collectively, these results suggest that the endogenous production of IL-12 resulting from the CD40-CD40L interaction between antigen-presenting cells and CD4+ T cells in the tumor-draining LNs may play a role in the persistence of the antitumor effects seen after IL-12 treatment.

Animals↗
PubMed1998

Detection of telomerase activity in prostate needle-biopsy samples.

BACKGROUND: Telomerase in an enzyme ribonucleoprotein responsible for cell immortality and oncogenesis. Telomerase activity has been detected in most cancers, including prostate cancer. To verify whether the detection of telomerase in prostate needle biopsy samples could have diagnostic value, we blindly assayed telomerase activity in samples from patients who were clinically suspected of having prostate cancer. METHODS: A total of 183 prostate biopsy samples was obtained from 63 patients who were suspected of having prostate cancer. Telomerase activity was determined by polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP) assay. An internal telomerase assay standard (ITAS) was used in this study to distinguish false negatives. RESULTS: Telomerase activity was detected in 17 of 19 (89.5%) patients with prostate cancer (chi(2) test, P < 0.005). In 39 of 42 (92.9%) biopsy samples from these 19 prostate cancer patients, confirmed histologically as prostate cancer, telomerase activity (chi(2) test, P < 0.005) was detected. Meanwhile, we also found one false-positive sample. In contrast, all of 44 normal or benign prostate disease patients (124 biopsy specimens) were telomerase-negative. We also revealed that poorly differentiated prostate cancer often expresses a high level of telomerase activity. The area of cancer tissue in biopsy specimens was not associated with relative telomerase activity. CONCLUSIONS: This study suggests that determination of telomerase activity in prostate needle-biopsy samples might be a useful tool for detecting prostate cancer.

Adenocarcinoma↗
PubMed1998

Selective separation of trypsin from pancreatin using bioaffinity in reverse micellar system composed of a nonionic surfactant.

Selective separation of trypsin from a mixture involving many kinds of contaminating proteins, i.e., pancreatin, was achieved using trypsin inhibitor immobilized in the reverse micelles, which were composed of a nonionic surfactant, tetra-oxyethylene monodecylether. To determine the efficient operations throughout the whole separation process we examined the operating conditions, which affect the immobilization efficiency of trypsin inhibitor and also the forward and backward extractions of trypsin. Fifty percent of the recovery of trypsin from pancreatin was realized with no loss of activity of the recovered trypsin.

Animals↗
PubMed1998

Radioimmunodetection of human myeloma xenografts with a monoclonal antibody directed against a plasma cell specific antigen, HM1.24.

BACKGROUND: To develop a new immunologic approach to multiple myeloma, the authors generated a monoclonal antibody against a human plasma cell specific antigen, HM1.24. Their previous study showed the antitumor effect of this antibody in severe combined immunodeficiency (SCID) mice bearing human myeloma xenografts. In the current study, the efficacy of anti-HM1.24 immunoglobulin (Ig) G and its F(ab')2 fragment were evaluated for radioimmunologic detection of the myeloma xenografts. METHODS: SCID mice bearing subcutaneous RPMI 8226 tumors were injected with 125I-labeled antibodies, and radioactivity in the tumor and normal tissues was measured. Radioimmunoscintigraphy and autoradiography were performed to investigate the distribution of the antibodies. RESULTS: In comparative biodistribution studies, the maximum tumor localization index of anti-HMl.24 F(ab')2 fragment was significantly higher than that of anti-HM1.24 IgG. Anti-HM1.24 F(ab')2 consistently had higher tumor-to-tissue ratio than anti-HM1.24 IgG and gave distinct tumor images by radioimmunoscintigraphy. Autoradiographic study showed that anti-HM1.24 F(ab')2 penetrated the tumor mass more uniformly than whole IgG antibody. CONCLUSIONS: These results indicate that anti-HM1.24 antibody has the potential to provide a new approach to the immunodetection and immunotherapy of multiple myeloma and related plasma cell dyscrasias.

Animals↗
PubMed1998

Natural killer-like nonspecific tumor cell lysis mediated by specific ligand-activated Valpha14 NKT cells.

We have recently identified alpha-galactosylceramide (alpha-GalCer) as a specific ligand for an invariant Valpha14/Vbeta8.2 T cell receptor exclusively expressed on the majority of Valpha14 NKT cells, a novel subset of lymphocytes. Here, we report that alpha-GalCer selectively activates Valpha14 NKT cells resulting in prevention of tumor metastasis. The effector mechanisms of the ligand-activated Valpha14 NKT cells seem to be mediated by natural killer (NK)-like nonspecific cytotoxicity. Indeed, the cytotoxic index obtained by alpha-GalCer-activated Valpha14 NKT cells was reduced by the addition of cold target tumor cells or by treatment with concanamycin A, which inhibits activation and secretion of perforin, but not by mAbs against molecules involved in the NKT cell recognition and conventional cytotoxicity, such as CD1d, Vbeta8, NK1. 1, Ly49C, Fas, or Fas ligand. These results suggest that the ligand-activated Valpha14 NKT cells kill tumor cells directly through a CD1d/Valpha14 T cell receptor-independent, NK-like mechanism.

Animals↗
PubMed1998

An open rectifier potassium channel with two pore domains in tandem cloned from rat cerebellum.

Tandem pore domain K+ channels represent a new family of ion channels involved in the control of background membrane conductances. We report the structural and functional properties of a TWIK-related acid-sensitive K+ channel (rTASK), a new member of this family cloned from rat cerebellum. The salient features of the primary amino acid sequence include four putative transmembrane domains and, unlike other cloned tandem pore domain channels, a PDZ (postsynaptic density protein, disk-large, zo-1) binding sequence at the C terminal. rTASK has distant overall homology to a putative Caenorhabditis elegans K+ channel and to the mammalian clones TREK-1 and TWIK-1. rTASK expression is most abundant in rat heart, lung, and brain. When exogenously expressed in Xenopus oocytes, rTASK currents activate instantaneously, are noninactivating, and are not gated by voltage. Because rTASK currents satisfy the Goldman-Hodgkin-Katz current equation for an open channel, rTASK can be classified an open rectifier. Activation of protein kinase A produces inhibition of rTASK, whereas activation of protein kinase C has no effect. rTASK currents were inhibited by extracellular acidity. rTASK currents also were inhibited by Zn2+ (IC50 = 175 microM), the local anesthetic bupivacaine (IC50 = 68 microM), and the anti-convulsant phenytoin ( approximately 50% inhibition at 200 microM). By demonstrating open rectification and open probability independent of voltage, we have established that rTASK is a baseline potassium channel.

Acids↗
PubMed1998

Systemic administration of interleukin-12 can restore the anti-tumor potential of B16 melanoma-draining lymph node cells impaired at a late tumor-bearing state.

We investigated the effect of the systemic administration of interleukin (IL)-12 on the anti-tumor potential of tumor-draining lymph nodes (LNs). Tumor-draining LN cells on day 10 after s.c. inoculation of B16 melanoma showed a significant anti-tumor effect against established pulmonary metastases after in vitro expansion, whereas those on either day 20 or 30 exhibited an impaired anti-tumor potential. However, i.p. injections of IL-12 (0.5 microg) on days 18, 20 and 22 significantly increased the total number of tumor-draining LN cells on day 24 and, furthermore, restored their anti-tumor potential after in vitro expansion. In addition, i.p. injection of IL-12 (0.1 microg) on days 20, 22, 24, 26 and 28 significantly suppressed the growth of s.c.-inoculated B16 melanoma and finally cured the tumors in 6 of 12 mice (50%), whereas dissection of the tumor-draining LNs on day 18, prior to the IL-12 treatment, decreased both the IL-12-induced anti-tumor effect and the percentage of cured mice (8.3%). Cured mice acquired a specific protective immunity. Collectively, our results indicate that the systemic administration of IL-12 can restore the immunotherapeutic potential of tumor-draining LNs, which was impaired at the late tumor-bearing state, and that the IL-12-induced systemic anti-tumor activity is preceded by the restoration of an anti-tumor response in tumor-draining LNs.

Animals↗
PubMed1998

Molecular cloning and partial characterization of a tobacco cDNA encoding a small bZIP protein.

Here we report the isolation of a tobacco cDNA which is a counterpart gene of rice low-temperature-induced lip19. Expression of the gene (termed tbz17) is also positively controlled by low temperature but fairly moderately compared with the low-temperature-responsiveness of rice lip19 and the maize counterpart gene, mlip15. The predicted gene product (termed TBZ17) is a bZIP protein of 145 amino acids and shows about 45% identity with rice LIP19 and maize mLIP15 proteins. DNA binding studies indicate that TBZ17 has quite similar DNA binding characteristics to that of mLIP15. The results suggest that low-temperature-induced gene(s) encoding a DNA binding factor with bZIP motif is omni-present in higher plants.

Amino Acid Sequence↗
PubMed1998

Dipeptidyl peptidase III is a zinc metallo-exopeptidase. Molecular cloning and expression.

We have purified dipeptidyl peptidase III (EC 3.4.14.4) from human placenta. It had a pH optimum of 8.8 and readily hydrolysed Arg-Arg-beta-naphthylamide. Monoamino acid-, Gly-Phe-, Gly-Pro- and Bz-Arg-beta-naphthylamides were not hydrolysed at all. The enzyme was inhibited by p-chloromercuriphenylsulphonic acid, metal chelators and 3,4-dichloroisocoumarin and contained 1 mol of zinc per mol of enzyme. The zinc dissociation constant was 250 fM at pH 7. 4 as determined by the zinc binding study. We isolated, by immunological screening of a Uni-ZAP XR cDNA library constructed from rat liver mRNA species, a cDNA clone with 2633 bp encoding the rat enzyme. The longest open reading frame encodes a 827-residue protein with a theoretical molecular mass of 92790 Da. Escherichia coli SOLR cells were infected with the pBluescript phagemid containing the cloned cDNA and established the overexpression of a protein that hydrolysed Arg-Arg-beta-naphthylamide. The recombinant protein was purified and the amino acid sequence of the protein was confirmed. We presumed that the putative zinc-binding domain involved in catalysis was present in the recombinant enzyme. It was a novel zinc-binding motif in that one amino acid residue was inserted into the conserved HEXXH motif characteristic of the metalloproteinases.

Amino Acid Sequence↗
PubMed1998

Bone marrow necrosis in a patient with acute myeloblastic leukemia during administration of G-CSF and rapid hematologic recovery after allotransplantation of peripheral blood stem cells.

Allogeneic peripheral blood stem cell transplantation from an HLA-identical sibling was performed for a 38-year-old male with refractory acute myeloblastic leukemia. The patient was conditioned with total body irradiation (TBI) and high-dose cytosine arabinoside (Ara-C). G-CSF (300 microg/body) was started for priming of residual leukemic cells 24 hr before the beginning of TBI (day -9). However, intolerable generalized bone pain appeared shortly after the start of first dose of G-CSF, and persisted for 3 days in spite of the cessation of G-CSF. Posttransplant hematopoietic engraftment was very rapid. Bone marrow biopsy specimens on day 14 and 30 showed typical bone marrow necrosis histologically. This is the first case of bone marrow necrosis during administration of G-CSF, and our experience suggests that PBSC could repopulate hematopoiesis in spite of severe bone marrow necrosis.

Adult↗
PubMed1998

The present mercury contents of scalp hair and clinical symptoms in inhabitants of the Minamata area.

A total of 191 fishermen and their family (32-82 years) living in some mercury-polluted areas along the Shiranui Sea volunteered for the present study. They made a living by fishery and had formerly eaten the methyl mercury-contaminated fish and shellfish caught there. The questionnaire on subjective symptoms, fish eating habits, and past living history was conducted on the subjects. In addition, they were clinically examined in detail by several neurologists and scalp hair was collected. With six exceptions, all the 185 subjects showed a normal total mercury level in hair (<10 ppm). The ratio of methyl mercury to total mercury was 79-94% on the average for each group examined, suggesting indirect contamination (perhaps through the food chain). Despite their low mercury level in scalp hair, however, the subjects showed various neurological symptoms, particularly, sensory disturbance (such as the glove and stocking type), at a very high rate. Thus, it seems fair to state that, in addition to officially recognized Minamata disease patients, there still exist many people with atypical, slight Minamata disease on the coast of the Shiranui Sea. The current hair mercury level is not necessarily useful as a criterion for diagnosing chronic Minamata disease because of the long lapse of time.

Adult↗
PubMed1998

Heat shock proteins and the antitumor T cell response.

Heat shock proteins (HSP) have been shown to participate in the antitumor T cell response. First, HSP play a crucial role in the intracellular pathway for antigen processing where HSP can make complexes with a broad spectrum of cellular proteins and peptides through their chaperone functions. In this pathway, macrophages are required for processing the chaperoned peptides to make stable molecules with the major histocompatibility complex (MHC) class I molecules, even when HSP-peptide complexes are exogenously administered. Through this pathway, vaccination with HSP-peptide complexes is thus able to elicit the response of CD8+ T cells specific for the chaperoned peptides. These findings suggest an essential role of HSP in 'cross-priming' and their usefulness for antitumor vaccination with tumor peptides. Second, HSP have been suggested to be expressed on the cell surface by transformation and, in addition, to function as antigen-presenting molecules for double negative T cells. Third, HSP derived from tumor cells have reportedly been recognized by T cells with either T cell receptor (TCR)-alphabeta or TCR-gammadelta. These lines of evidence therefore indicate that HSP may be potentially promising target molecules for antitumor T cell immunotherapy.

Animals↗
PubMed1998

Drug susceptibility of PCA in WBB6F1-W/Wv mice.

Our previous study revealed that passive cutaneous anaphylaxis (PCA) can be produced in congenitally mast cell-deficient WBB6F1-W/Wv (abbreviated as W/Wv) mice on sensitization with undiluted or slightly diluted allogeneic and xenogeneic antisera but not on sensitization with allogeneic monoclonal immunoglobulin (Ig)E and IgG1 antibodies regardless of the antibody concentration [1]. In view of these findings, the present study was conducted to characterize PCA in this strain from its drug susceptibilities using mast cell-bearing WBB6F1-(+)/+ (abbreviated as +/+) and B6D2F1 mice as references. PCA in W/Wv mice mediated by a low dilution (1:4) of hyperimmune serum to bovine serum albumin of the B6D2F1 mouse origin was markedly suppressed by CV-6209, an antagonist of platelet-activating factor (PAF), but not by antihistamines such as cyproheptadine and oxatomide. In contrast, PCA in +/+ and B6D2F1 mice mediated by a high dilution (1:128) of the anti-serum (virtually by IgG1 antibody) was nearly completely suppressed by antihistamines but not by CV-6209. A remarkable difference between PCA in W/Wv and reference mice was also observed in the susceptibility to monoclonal anti-mouse granulocyte (Gr-1) antibody: PCA in W/Wv mice was potently suppressed by the 1- to 3-day pretreatment with this antibody but that in references was not at all. Putting these present results together with the previous finding that anti-granulocyte antibody greatly reduces circulatory Gr-1+ leukocytes, 1 to 3 days after the treatment [2], it is highly probable that PCA in W/Wv mice mediated by some antibody isotypes other than IgE and IgG1 is produced by PAF mainly released from Gr-1+ cells, while IgG1 antibody-mediated PCA in mast cell-bearing reference mice is evoked by histamine derived from mast cells. PCA homologous to that in W/Wv mice could also be produced in the reference mice on sensitization with undiluted or slightly diluted antiserum, when generalized blueing due to excess IgG1 antibody was removed by the oxatomide treatment before the antigen challenge.

Animals↗