Biomedical subjects

N Nishi

Publications and source records attributed to N Nishi.

At least 19 recordsLinked to original sources

PubMed2005

The potyvirus associated with the dappled fruit of Passiflora edulis in Kagoshima prefecture, Japan is the third strain of the proposed new species East Asian Passiflora virus (EAPV) phylogenetically distinguished from strains of Passion fruit woodiness virus.

A potyvirus (isolate IB) causing dappled or faded fruits and foliar mosaic symptoms of purple passionfruit, was found in the botanical garden of Kagoshima University, Japan. This isolate--differed in host range from isolates of Passion fruit woodiness virus (PWV)-AO, previously reported to cause "woodiness" in Japan. Isolates IB and AO had 83% amino acid identity in their coat proteins (CPs). In phylogenetic analysis, East Asian isolates IB, AO, and PWV-Taiwan clustered together, and were distinguishable from Australian PWV and Brazilian Cowpea aphid-borne mosaic virus isolates, which also cause "woodiness" in passionfruit. We propose the name "East Asian Passiflora virus (EAPV)" for the new potyvirus species.

Capsid Proteins↗

PubMed2005

Retinoic acid-inducible gene-I is induced by interleukin-1beta in cultured human gingival fibroblasts.

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box family protein, and details of its biological function are not known. We have studied the mechanism of the interleukin-1beta (IL-1beta)-induced RIG-I expression in human gingival fibroblasts in culture. We also addressed the possibility of enhanced expression of COX-2, RANTES and galectin-9 in fibroblasts overexpressed RIG-I. We stimulated cultured human gingival fibroblasts with IL-1beta and examined the expression of RIG-I mRNA and protein by reverse transcriptase-mediated polymerase chain reaction and Western blot analysis. The effect of cycloheximide, a protein synthesis inhibitor, on the IL-1beta-induced expression of RIG-I was examined. The expression of COX-2, RANTES, galectin-9 and monocyte chemoattractant protein-1 in gingival fibroblasts transfected with RIG-I cDNA was also examined. IL-1beta stimulated the expressions of mRNA and protein for RIG-I, in cultured fibroblasts, in a time- and concentration-dependent manner. Cycloheximide did not suppress the IL-1beta-induced RIG-I expression. Introduction of RIG-I cDNA into fibroblasts resulted in enhanced expression of COX-2 mRNA, and slightly enhanced the expression of mRNA for RANTES and galectin-9. In contrast, RIG-I overexpression did not alter the level of mRNA for monocyte chemoattractant protein-1. We conclude that IL-1beta stimulates RIG-I expression in human gingival fibroblasts.

Blotting, Western↗

PubMed2005

dsRNA enhances eotaxin-3 production through interleukin-4 receptor upregulation in airway epithelial cells.

The exacerbation of asthma during viral infections is mainly explained by neutrophils infiltrating into the airways. However, enhanced functions of eosinophils are also observed. The aim of this study was to reveal the mechanism of how eosinophils are activated during and after viral infection of the airways, using a model of viral infection. A synthetic double-stranded RNA, poly inosinic-cytidyric acid (poly(IC)), was transfected to a human airway epithelial cell line (BEAS-2B) and the primary bronchial epithelial cells, to mimic a viral infection. The production of chemokines from the cells was investigated. The transfection of poly(IC), alone, marginally affected the eotaxin-3 production of the cells. However, the transfection of poly(IC) prior to interleukin (IL)-4 stimulation enhanced eotaxin-3 production. Poly(IC) transfection increased mRNA and protein expressions of IL-4 receptor (R)alpha and IL-2Rgamma, components of the IL-4R. In BEAS-2B cells, IL-4-mediated phosphorylation of signal transducer and activator of transcription six was enhanced in poly(IC) transfected cells. This was reversed by the addition of anti-IL-4Ralpha antibody, suggesting the role of an increased number of IL-4 receptors in enhanced IL-4-induced eotaxin-3 production. Poly(IC)-induced upregulation of IL-4Ralpha was inhibited by treatment with cycloheximide or dexamethasone. In conclusion, these results suggest that viral airway infection may enhance interleukin-4-induced eotaxin-3 production through upregulation of the interleukin-4 receptor in airway epithelial cells.

Cells, Cultured↗

PubMed2004

Preparation of polysulfone hollow microspheres encapsulating DNA and their functional utilization.

Polysulfone hollow microspheres encapsulating DNA were prepared using a liquid-liquid phase separation technique. The microspheres were then used to absorb a DNA-binding intercalating material--ethidium bromide. The amount of DNA encapsulated in the microspheres depended on the concentration of the DNA solution used to prepare the microspheres, and the microsphere morphology depended on both the polymer concentration and the preparation conditions. The amount of ethidium bromide in the microspheres depended mainly on the amount of encapsulated DNA, and the microsphere morphology also affected the removal of the ethidium bromide. The new method of DNA encapsulation is proposed, and the microspheres encapsulating the DNA have the potential to be used in environmental applications.

Animals↗

PubMed2001

Identification of homologous biologically active sites on the N-terminal domain of laminin alpha chains.

Laminin, a multifunctional glycoprotein of the basement membrane, consists of three different subunits, alpha, beta, and gamma chains. To date, five different alpha chains have been identified. N-terminal domain VI in the alpha1 chain has various biological activities. Here we screened biologically active sequences on domain VI of the laminin alpha2, alpha3, and alpha5 chains using a large number of overlapping peptides. HT-1080 human fibrosarcoma cell attachment to the peptides was evaluated using peptide-coated plastic plates and peptide-conjugated Sepharose beads. We identified four cell adhesive sequences from laminin alpha2 chain domain VI, two sequences from the alpha3 chain, and two sequences from the laminin alpha5 chain. Sequences homologous to A13 (RQVFQVAYIIIKA, alpha1 chain 121-133) on all the alpha chains (FQIAYVIVKA, alpha2 chain 130-139; GQLFHVAYILIKF, alpha3 chain 96-108; FHVAYVLIKA, alpha5 chain 74-83) showed strong cell attachment activity. A5-16 (LENGEIVVSLVNGR, alpha5 chain 147-160) showed the strongest cell attachment activity in the plate assay, and the homologous peptide in the alpha3 chain promoted similar strong cell attachment activity. A5-16 and its homologous peptide in the alpha2 chain promoted moderate cell attachment, while the homologous peptide to A5-16 in the alpha1 chain did not show activity. A2-7 (SPSIKNGVEYHYV, alpha2 chain 108-120) showed cell attachment activity only in the plate assay, but homologous sequences in the alpha1, alpha3, and alpha5 chains did not promote activity. A2-7 promoted endothelial cell sprouting from aortic rings in vitro and melanoma colonization to murine lungs in vivo. However, none of the homologous peptides of A2-7 promoted experimental pulmonary metastasis by B16-BL6 melanoma cells. These results indicate that there are chain-specific active sites in domain VI of the laminin alpha chains, some of which contain conserved activities.

Amino Acid Sequence↗

PubMed2001

Interleukin-1beta stimulates galectin-9 expression in human astrocytes.

Galectin-9 is an eosinophil chemoattractant produced by activated T lymphocytes. We have addressed expression of galectin-9 in normal human astrocytes in culture. Expression of galectin-9 mRNA and protein were examined by reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immunofluorescent staining. Interleukin-1beta (IL-1beta) was found to enhance the galectin-9 expression in time- and concentration-dependent manners. Galectin-9 protein was detected in the membrane fraction, 105 000 x g precipitate, and immunofluorescent staining revealed diffuse cellular and perinuclear distributions. Dexamethasone pretreatment almost completely suppressed the production. We conclude that astrocytes produce galectin-9 in response to the stimulation with IL-1beta, and this may contribute to inflammatory reactions in the CNS.

Anti-Inflammatory Agents↗

PubMed2001

Potent expansion of human natural killer T cells using alpha-galactosylceramide (KRN7000)-loaded monocyte-derived dendritic cells, cultured in the presence of IL-7 and IL-15.

Natural killer T (NKT) cells have an extremely restricted T-cell receptor repertoire, in man consisting of a Valpha24 chain preferentially paired with a Vbeta11 chain, and play crucial roles in various immune responses. Characterization of circulating Valpha24(+)Vbeta11(+)-T cells is hampered by their low frequencies. The alpha-galactosylceramide KRN7000 was reported to be presented by CD1d to NKT cells. Since dendritic cells (DC) are potent antigen presenting cells, and have been shown to express CD1d, we analyzed whether these cells could efficiently mediate expansion of Valpha24(+)Vbeta11(+)-T cells. During a 7-day co-culture of peripheral blood mononuclear cells and KRN7000-loaded mature monocyte derived DC (moDC) in the presence of interleukin-7 (IL-7) and IL-15, we observed up to 76-fold expansion of Valpha24(+)Vbeta11(+)-T cells. The expanded Valpha24(+)Vbeta11(+)-T cells expressed the cytotoxic molecule granzyme B, showed negligible expression of Fas ligand and could be induced to express high levels of interferon-gamma, while retaining the capacity to produce IL-4. B cells, expressing CD1d, could also present KRN7000, but Valpha24(+)Vbeta11(+)-T cell expansion was only observed in the presence of IL-7 and/or IL-15. Considering the low frequency of circulating Valpha24(+)Vbeta11(+)-T cells, the present method for expansion of Valpha24(+)Vbeta11(+)-T cells using KRN7000-loaded mature moDC will be of value for the further characterization of this unique T cell subset.

Adult↗

PubMed2001

Circulating V(alpha24+) Vbeta11+ NKT cell numbers are decreased in a wide variety of diseases that are characterized by autoreactive tissue damage.

Natural killer T (NKT) cells have been implicated as playing an important role in regulating immune responses. Defects in the NKT cell population were reported in animal autoimmune disease models and in distinct human autoimmune diseases. Here, we report that circulating V(alpha24+) Vbeta11+ NKT cell numbers are decreased in a broad variety of disorders with (auto)immune-mediated pathology, affecting the skin, bowel, central nervous system, and joints, regardless of disease duration or activity. Remarkably, normal circulating V(alpha24+) Vbeta11+ NKT cell numbers were found in Graves disease and coeliac disease. Since earlier studies noted a rise in NKT cells in myasthenia gravis, the picture emerges in which a defective NKT cell population is associated with autoreactive tissue damage rather than with the propensity to develop autoimmune disease. The present data support the idea that therapies aiming at the in vivo expansion of regulatory NKT cells might help to control immune-mediated damage in autoimmune disease.

Antigens, CD1↗

PubMed2001

UV-irradiation-induced DNA immobilization and functional utilization of DNA on nonwoven cellulose fabric.

Immobilization of double-stranded DNA onto nonwoven cellulose fabric by UV irradiation and utilization of DNA-immobilized cloth were examined. The immobilized DNA was found to be stable in water, with the maximum amount of fabric-immobilized DNA being approximately 20 mg/g of nonwoven fabric. The DNA-immobilized cloth could effectively accumulate endocrine disruptors and harmful DNA intercalating pollutants, such as dibenzo-p-dioxin, dibenzofuran, biphenyl, benzo[a]pyrene and ethidium bromide. Additionally, DNA-immobilized cloth was found to bind metal ions, such as Ag+, Cu2+, and Zn2+. The maximum amounts of bound Ag+, Cu2+, and Zn2+ onto DNA-immobilized cloth (1 g) were approximately 5, 2, and 1 mg, respectively. DNA-immobilized cloth containing Ag+ showed antibacterial activity against Escherichia coli and Staphylococcus aureus. DNA-immobilized cloth without metal ion and with Cu2+ or Zn2+ did not show antibacterial activity. These results suggest that immobilized DNA imparts useful functionality to cloth. DNA-immobilized cloth prepared by UV irradiation has potential to serve as a useful biomaterial for medical, engineering, and environmental application.

Cellulose↗

PubMed2001

Characterization and formation mechanism of water-insoluble DNA-matrix induced by UV irradiation.

We have prepared water-insoluble and nuclease resistant DNA-matrixes by UV irradiation. The UV-irradiated DNA-matrix could effectively accumulate and condense harmful DNA-intercalating compounds, such as acridine orange (AO) and ethidium bromide (EB), from diluted aqueous solutions. The binding constant of AO and EB for UV-irradiated DNA were determined to be 1.0 (+/- 0.2) x 10(5) M-1 and 6.8 (+/- 0.3) x 10(4) M-1, respectively; values consisted with reported results for non-irradiated DNA. In addition, the agarose gel electrophoresis and AFM measurements indicate that DNA matrix forms an intermolecular cross-linking structure with the radical reaction. The UV-irradiated DNA-matrixes have potential uses as a biomaterial filter for the removal of harmful DNA intercalating compounds.

Acridine Orange↗

PubMed2001

Effects of hostility and lifestyle on coronary heart disease among middle-aged urban Japanese.

OBJECTIVE: To explore the association between multi-dimensional aspects of hostility and coronary heart disease among middle-aged urban Japanese. SUBJECTS AND METHODS: We conducted a case-control study. Cases were consecutive patients with acute coronary syndrome admitted to a hospital in Japan. Fifty-three patients (45 men and 8 women) aged 35 to 65 were enrolled. For each case, two sex and age (+/-2 years) matched controls were recruited from among participants in a health check-up program at a health promotion center located in the same area as the hospital. Two questionnaires, both with four components, were used to measure hostility and coping with anger: the one was for anger, hostility, physical aggression and verbal aggression, and the other for aggression, social inhibition, guilt, and controlled affect. RESULTS: The scores of all components from two questionnaires were higher for cases than controls, but the differences were not significant. Multivariate analysis showed that anger, fat intake, alcohol consumption and house size were significantly associated with the etiology of acute coronary syndrome. CONCLUSION: Anger, lifestyle, and socioeconomic status play important roles for the etiology of coronary heart disease in middle-aged urban Japanese.

Case-Control Studies↗

PubMed2001

Collagen-binding domain of a Clostridium histolyticum collagenase exhibits a broad substrate spectrum both in vitro and in vivo.

The substrate spectrum of the tandem collagen-binding domain (CBD) of Clostridium histolyticumclass I collagenase (ColG) was examined both in vitro and in vivo. CBD bound to insoluble type I, II, III and IV collagens in vitro, and to skin, aorta, tendon, kidney, trachea and corneal tissues containing various types of collagen fibrils or sheets. CBD bound to all kinds of collagen fibrils regardless of their diameters and also bound to sheet-forming collagen in the glomerular basal lamina or Descemet's membrane of the cornea. This wide substrate spectrum expands possible applications of the drug delivery system we proposed previously (PNAS 95:7018-7023, 1998). Therapeutic agents fused with CBD will bind not only to subcutaneous tissues, but also to other tissues containing non-type I collagen.

Animals↗

PubMed2001

Radiosurgery-induced brain tumor. Case report.

The authors describe a case of glioblastoma multiforme (GBM) associated with previous gamma knife radiosurgery for a cerebral arteriovenous malformation (AVM). A 14-year-old boy had undergone radiosurgery for an AVM, which was performed using a 201-source 60Co gamma knife system at another institution. The maximum and margin radiation doses used in the procedure were 40 and 20 Gy, respectively. One year after radiosurgery, the patient noticed onset of mild left hemiparesis due to radiation necrosis. Six and one-half years after radiosurgery, at the age of 20 years, the patient experienced an attack of generalized tonic-clonic seizure. Magnetic resonance (MR) imaging revealed the existence of a brain tumor in the right parietal lobe. The patient underwent an operation and the histological diagnosis of the lesion was GBM. Ten months following the operation, that is, 99 months postradiosurgery, this patient died. To the best of the authors' knowledge, this is the first reported case of a neoplasm induced by radiosurgery for an AVM and the second case in which it occurred following radiosurgery for intracranial disease.

Brain Neoplasms↗

PubMed2001

[Neuroprotective effect of a neurotoxin, 3-nitropropionic acid, against hypoxic damage to the gerbil hippocampus: neuroprotection after the onset of hypoxic depolarization].

Ischemic/hypoxic tolerance induced by a subtoxic dose of neurotoxin, 3-nitropropionic acid(3-NPA), was recently reported as "chemical preconditioning". We previously showed that the neuroprotective effect by chemical preconditioning with 3-NPA was induced by prolonging the delay to hypoxic depolarization (HD) via activating adenosine receptors. In this study, we electrophysiologically assessed whether the protective effect of chemical preconditioning was potent after the onset of HD. An in vitro hippocampal slice model from adult gerbils was used to study the delay to HD during hypoxia and the recovery of synaptic responses after hypoxia. Hypoxia was sustained until a fixed period(8 min) following HD. These responses were examined in control slices and slices pretreated with subtoxic dose of 3-NPA(4 mg/kg) intraperitoneally at 3 hours prior to slice preparation. The delay to hypoxic depolarization in 3-NPA treated slices was significantly prolonged(p < 0.05). The field excitatory postsynaptic potential recovery after a fixed period of hypoxia under HD was also significantly improved in the 3-NPA treated group(48.6 +/- 23.8%) compared with the control group(29.2 +/- 12.2%) (p < 0.05). This finding indicates that chemical preconditioning with 3-NPA induces the neuroprotective effect against hypoxic damage after as well as before the onset of HD to the hippocampus.

Animals↗

PubMed2000

Human natural killer T cells acquire a memory-activated phenotype before birth.

Natural killer T (NKT) cells have recently been shown to play an important role in the rejection of malignant tumors and in the regulation of autoimmune diseases. Potent antitumor effects of the marine sponge-derived NKT cell ligand KRN7000 were observed in mice. Therefore, the elucidation of the natural ligand of NKT cells, which is currently still unknown, might have important clinical consequences for the treatment of cancer and autoimmune diseases. Analysis of cord blood mononuclear cells from healthy term infants demonstrated that in sharp contrast with the vast majority of cord blood lymphocytes, human NKT cells have already acquired a memory-activated phenotype before birth. This observation indicates that NKT cells encounter a natural ligand during fetal life and that this ligand is unlikely to be of microbial origin.

Adult↗

PubMed2000

Requirement of divalent galactoside-binding activity of ecalectin/galectin-9 for eosinophil chemoattraction.

We have previously isolated and cloned a novel eosinophil chemoattractant (ECA) from a human T-cell-derived expression library. This ECA, termed ecalectin, is a variant of human galectin-9, a member of a beta-galactoside binding animal lectin family, which contains two conserved carbohydrate recognition domains (CRDs). In the present study, we addressed whether carbohydrate binding activity is required for the ECA activity of ecalectin and whether both CRDs are essential for this activity. Recombinant full-length wild-type ecalectin (ecalectin-WT) and N-terminal and C-terminal CRD (ecalectin-NT and -CT, respectively) were generated. All of these recombinant proteins exhibited affinity for lactose, a property shared by galectins, but ecalectin-WT exhibited substantially higher hemagglutination activities than ecalectin-NT and -CT. Furthermore, ecalectin-WT showed over 100-fold higher ECA activity than ecalectin-NT and -CT; combination of recombinant domain fragments did not reconstitute the ECA and hemagglutination activities of the full-length protein. ECA activity of ecalectin-WT was inhibited by lactose in a dose-dependent manner. Site-directed mutation of positions Arg(65) of ecalectin-NT and Arg(239) of ecalectin-CT to an aspartic acid residue resulted in the loss of both lactose-binding and ECA activities. We conclude that divalent galactoside-binding activity is required for eosinophil chemoattraction by ecalectin.

Antigens, Differentiation↗

PubMed2000

Functional coupling of GABA(B) receptors with G proteins that are sensitive to N-ethylmaleimide treatment, suramin, and benzalkonium chloride in rat cerebral cortical membranes.

Although it is known that GABA(B) receptors are negatively coupled to adenylyl cyclase, the detailed selectivity of functional interaction between GABA(B) receptors and Gi subfamily members is still ambiguous. (+/-)-Baclofen-stimulated high-affinity GTPase activity, which was competitively antagonized by 2-hydroxy-saclofen, was attenuated by pretreatment of the membranes with N-ethylmaleimide (NEM) in a concentration- and incubation period-dependent manner. The NEM-pretreated (50 microM, 15 min at 4 degrees C) membranes restored the (+/-)-baclofen-sensitive high-affinity GTPase activity when reconstituted with pertussis toxin-sensitive bovine brain G proteins. Among recombinant rat Galpha subunits, G(i alpha(-2)) appeared most effective as compared with other subunits (G(i alpha(-2)) > G(i alpha(-3) > G(i alpha(-1) = G(o alpha). The GABA(B) receptor-mediated high-affinity GTPase activity was also completely eliminated by 100 microM suramin and by 100 microM benzalkonium chloride. These results indicate that GABA(B) receptors in rat cerebral cortex couple to NEM-sensitive G proteins, in particular Gi2, which are sensitive to suramin and benzalkonium chloride.

Adenylate Cyclase Toxin↗

PubMed2000

Open pergolide treatment of tricyclic and heterocyclic antidepressant-resistant depression.

BACKGROUND: Recently, a dopamine hypothesis of depression was put forward, and several studies have demonstrated that direct and indirect dopamine agonists have antidepressant effects. METHODS: Using Clinical Global Impressions, we evaluated the efficacy of 4-week treatment of pergolide as an antidepressant adjuvant involving 20 unipolar depressed patients who were refractory to standard treatment with antidepressants. RESULTS: One patients (5%) were very much improved, seven (35%) much improved, four (20%) minimally improved, six (30%) no change or worse, and two (10%) not assessed. There was no significant difference in any clinical factors between the pergolide responder and non-responder group. LIMITATIONS: This study was a non-blind open trial, and pergolide was added to tricyclic and heterocyclic antidepressants. CONCLUSION: Pergolide may be useful as an antidepressant adjuvant, suggesting a potential role for dopamine-2 stimulation in the antidepressant response.

Adult↗