Biomedical subjects

T Nishi

Publications and source records attributed to T Nishi.

At least 19 recordsLinked to original sources

PubMed2004

Formation of advanced tokamak plasmas without the use of an ohmic-heating solenoid.

A new operational scenario of advanced tokamak formation was demonstrated in the JT-60U tokamak. This was accomplished by electron cyclotron and lower hybrid waves, neutral beam injection, and the loop voltage supplied by the vertical field and shaping coils. The Ohmic heating (OH) solenoid was not used but a small inboard coil (part of the shaping coil), providing less than 20% of total poloidal flux, was used. The plasma thus obtained had both internal and edge transport barriers, with an energy confinement time of 1.6 times H-mode scaling, a poloidal beta of 3.6, and a normalized beta of 1.6, and a large bootstrap current fraction (>90%). This result opens up a possibility to reduce, and eventually eliminate, the OH solenoid from a tokamak reactor, which will greatly improve its economic competitiveness.

Journal Article↗

PubMed2004

Involvement of apoptosis in syncytial cell death induced by canine distemper virus.

The Yanaka strain, a field isolate of Canine distemper virus (CDV), caused extensive syncytial cytopathic effects (CPEs) followed by cell death in vitro. Syncytium formation is an important aspect of CDV pathogenicity, but the mechanism of the fusion-induced cell death is still not understood. In this study, the involvement of apoptosis in the CDV-induced CPE was investigated. We also examined apoptosis in cells infected with a persistent strain of CDV, the Yanaka-BP strain derived from the Yanaka strain, because this strain does not cause obvious CPE. DNA laddering together with Terminal transferase dUTP nick endlabeling (TUNEL) assay indicated that the Yanaka strain infection, but not the Yanaka-BP infection induced apoptosis. In addition, flow cytometric analysis similarly indicated that the Yanaka-BP strain induced apoptosis significantly less frequently than the Yanaka strain did. Thus, absence of apoptosis may be implicated in the CPE and establishment of persistent CDV infection.

Animals↗

PubMed2004

In vivo transfer of a neuronal nitric oxide synthase expression vector into the rat bladder by electroporation.

OBJECTIVE: To investigate the possibility of in vivo gene transfer by attempting to transfer the neuronal nitric oxide synthase (nNOS) gene into rat bladder using electroporation. MATERIALS AND METHODS: The bladder was exposed through an abdominal midline incision in 8-week-old male rats. Plasmid DNA of the marker genes green fluorescent protein (GFP) and luciferase, and the nNOS gene, was then injected into the subserosal space of the bladder and electroporation applied. At 72 h after gene transfer, GFP and luciferase were assayed in the isolated bladder and immunohistochemical staining used to detect nNOS; NO(x) released from isolated bladder strips was also assessed using microdialysis and high-performance liquid chromatography. RESULTS: From the luciferase assay, 45 V, 1 Hz, 50 ms and eight pulses were selected as the optimum conditions for electroporation. Bladder specimens with GFP genes injected by electroporation showed bright and numerous sites of GFP expression in the smooth muscle layer. In rats with the nNOS gene injected by electroporation there was marked nNOS immunoreactivity, and NO(x) released from bladder strips was significantly greater than in the control groups. CONCLUSIONS: These results suggest that electroporation is a useful technique for in vivo gene transfer into rat bladder smooth muscles, and that the nNOS gene transferred by this procedure functionally expresses and contributes to NO production.

Animals↗

PubMed2003

Inhibitory effects of Helicobacter pylori infection on murine autoimmune gastritis.

BACKGROUND AND AIM: Long term Helicobacter pylori infection leads to atrophic gastritis but the relation between H pylori infection and autoimmune related atrophic gastritis (AIG) remains unclear. We studied the effects of H pylori infection on the pathophysiology of AIG in mice. MATERIALS AND METHODS: BALB/c nu/nu mice (n=40) with or without H pylori infection received splenocytes from neonatally thymectomised mice to induce AIG. Half of the mice were orally infected with H pylori prior to AIG induction. Histological findings, and local and systemic immune responses were serially evaluated. RESULTS: Two and six months after transfer, parietal cells in uninfected mice were depleted while those in infected mice were well preserved. The degree of gland atrophy (p<0.01), hyperplasia (p<0.01), gastric pH (p<0.05), and serum gastrin levels of infected mice were significantly lower than those of uninfected mice. Serum antiparietal cell antibody levels gradually decreased in infected mice, and were significantly lower than those of uninfected mice at six months (p<0.05). Real time polymerase chain reaction studies revealed significantly higher interleukin 4 (p<0.05) and transforming growth factor beta (p<0.05) gene expression in the gastric mucosa in infected mice than in uninfected mice at both two and six months after AIG induction. CONCLUSIONS: H pylori infection inhibited the development of AIG in mice. Th2-type immune responses and transforming growth factor beta in the gastric microenvironment might be involved in the inhibitory effects of H pylori infection on the development of AIG, in which Th1-type responses have an important role.

Animals↗

PubMed2003

[Local advanced lung cancer invaded thoracic vertebral bodies with unruptured cerebral aneurysm].

A 57-year-old man presented with the chief complaint of left shoulder pain in June 2001, and paridrosis of left upper trunk and left upper limb in July 2001. Head magnetic resonance imaging (MRI) showed 8 mm sized unrupture aneurysm of left middle cerebral artery, and chest computed tomography (CT) showed the lung tumor invaded thoracic vertebral bodies. The local advanced lung carcinoma (cT4N0M0) and unrupture aneurysm of left middle cerebral artery was diagnosed. The prevented clipping of unrupture aneurysm was performed at 11th September 2001, and left upper lobectomy, hemivertebrectomy and reconstruction of thoracic vertebral body (Th 3-5) with Modul' ICS at 12th October 2001. The pathological findings revealed squamous cell carcinoma. The staging was pT4N0M0, IIIB. The postoperative course was uneventful. After the radiotherapy (50 Gy), chemotherapy (gemcitabine and vinorelbine) was performed. But the radiation pneumonia was occurred and chemotherapy was intermitted. The steroid was administrated due to the radiation pneumonia, and the complication was improved. He discharged at 17th April 2002 and had no recurrence. The prevented clipping of unrupture cerebral aneurysm and the reconstruction of thoracic vertebral body (Th 3-5) with Modul' ICS were useful for the radical operation of the local advanced lung cancer.

Carcinoma, Squamous Cell↗

PubMed2003

[Non-compromised grafting policy in off-pump coronary artery bypass].

BACKGROUND: The off-pump coronary artery bypass (OPCAB) has been prevalent around the world. However the most optimal selection of graft conduits has still been controversial. METHODS: Between January 2002 and April 2003, 126 consecutive isolated coronary artery bypass procedures were attempted to performed without cardiopulmonary bypass. A mean age of the patients was 69.3 (47-90). Fifteen patients were operated on emergently and 16 were urgently, including 15 patients requiring preoperative intra-aortic balloon pumping (IABP). Five patients underwent reoperative coronary bypass. RESULTS: All procedures were completed without cardiopulmonary bypass. The mean number of grafts per patient was 3.23 (range, 1 to 6). The skeletonized arterial conduits were aggressively used [117 left internal mammary artery (LIMA) to 155 sites, 70 right internal mammary artery (RIMA) to 79 sites, 57 right gastro-epiploic artery (RGEA) to 82 sites and 49 saphenous vein (SV) to 91 sites]. Cardiac-related hospital mortality was none. Angiographic assessment of grafts demonstrated that patency of LIMA, RIMA, RGEA and SV were 98.6%, 100%, 100%, and 97.6% respectively. CONCLUSION: OPCAB with skeletonized in situ arterial conduits is secure and feasible.

Aged↗

PubMed2002

Identification of DNA markers of tobacco linked to bacterial wilt resistance.

Bacterial wilt caused by Ralstonia solanacearum is one of the most destructive soil-borne diseases in the world. Breeding resistant commercial varieties of tobacco is difficult because most donor candidates' resistance is controlled by polygenes. In this paper, we demonstrate the identification of useful DNA markers for bacterial wilt-resistant tobacco breeding. One hundred and seventeen markers were identified by the amplified fragment length polymorphism (AFLP) method between W6, a burley variety with resistance originating from a Japanese domestic variety, Hatano, and Michinoku 1, a commercial burley wilt-susceptible variety, using 3,072 primer combinations. These markers were analyzed in 125 doubled haploid lines, derived from F(1) hybrids between W6 and Michinoku 1, and a linkage map consisting of ten linkage groups was drawn. The resistance phenotype of each of these lines was investigated on the basis of the average of disease severity obtained from field trials over two growing cycles. Quantitative trait loci (QTL) analysis was performed on the marker phenotypes and the resistance phenotype of each line. One QTL for the bacterial wilt resistance of W6 and DNA markers associated with this QTL were identified on a linkage group consisting of 15 markers, 32 cM in length. This QTL explained more than 30% of the variance in resistance among these lines.

Burkholderia↗

PubMed2002

Expression of lymphocyte-specific chemokines in human malignant glioma: Essential role of LARC in cellular immunity of malignant glioma.

Lymphocytes are frequently observed in human malignant glioma, the mechanism(s) underlying their appearance is not fully understood. To clarify tumor immunity in malignant gliomas, we analyzed the expression of 8 novel lymphocyte-specific chemokines in human glioma cell lines and glioma tissues by RT-PCR, Northern blot, immunoblot and immunohistochemistry, and examined the correlation with the infiltration of various subsets of lymphocytes. For the 8 chemokines examined (LARC, TARC, ELC, SLC, PARC, LEC, HCC-2, and SCM-1alpha), expression of LARC was clearly detectable in all 12 glioma cell lines by RT-PCR. Additionally, expression of TARC and SCM-1alpha was detectable in the majority of glioma cell lines. However, the expression level of most chemokines was low, so that Northern blot analysis could not demonstrate their expression with the exception of LARC in 2 cell lines. Expression of LARC mRNA and LARC protein was strongly induced by phorbol myristate ester in U87 MG cells. The production of LARC protein was demonstrated in 4 of 8 glioblastoma tissues by immunoblotting, and 9 of 33 samples (27.3%) by immunohistochemistry. Interestingly, the positivity of LARC staining was significantly correlated with the infiltration of CD8-, CD4-, and CD45R0-positive cells (p<0.001). Although the constitutive expression level of LARC is low, certain stimulations could strongly induce its expression, and play a crucial role in the tumor immunity of human malignant glioma.

Blotting, Northern↗

PubMed2001

Laparoscopic lumbar sympathectomy for lower-limb disease.

BACKGROUND: The standard procedure for sympathectomy is open surgery. The oblique retroperitoneal approach is popular because it provides good visibility, albeit at the expense of requiring a long skin incision. Chemical sympathectomy has been introduced as a less invasive means of achieving sympatholysis; however, this method is also associated with a significant incidence of incomplete block and transient denervation. Laparoscopic surgery is a new approach that simplifies various surgical procedures. The aim of our report was to evaluate the benefits of endoscopic retroperitoneal surgery for lumbar sympathectomies. METHODS: Between March 1997 and April 2000, seven patients underwent laparoscopic lumbar sympathectomy in our department (all men, with an average age or 45.1 years). The predominant presenting symptoms were unilateral pain at rest and lower-extremity coldness. Symphaectomy was performed using a retroperitoneal approach on six patients and an anterior transperitoneal approach on one patient. After laparoscopic lumbar sympathectomy, skin thermometry was carried out on all patients. RESULTS: The postoperative skin temperature of the affected leg rose to 36.6 +/- 0.5 degrees C, as compared to 33.8 +/- 0.8 degrees C preoperatively. After laparoscopic lumbar sympathectomy, none of the patients complained of neuralgia. All patients achieved sustained symptomatic relief, and no major postoperative complications were noted. CONCLUSIONS: Lumbar sympathectomy can be performed laparoscopically. Currently, our standard technique is the retroperitoneal approach. More clinical experience and long-term follow-up will ultimately determine if this will become the procedure of choice. However, we believe that a learning period is necessary for this technique to be fully mastered.

Adult↗

PubMed2001

Rectal immunization with antigen-containing microspheres induces stronger Th2 responses than oral immunization: a new method for vaccination.

The rectum as an effective site for induction of systemic and local immunity has received little attention. Rectal immunization with microspheres-containing ovalbumin (MS-OVA) was tested for its ability to elicit systemic and mucosal immune responses. Rectal immunization with MS-OVA enhanced both Th2 dominant OVA-specific IgG levels in the serum and OVA-specific IgA levels in fecal extracts more prominently than did oral immunization. Cytokine analysis of CD4(+) T cells indicated a predominant induction of Th2-type responses compared to Th1-type responses following rectal immunization compared to oral immunization. These results demonstrate that rectal immunization with microspheres could be an effective new vaccination method.

Administration, Oral↗

PubMed2001

NaBH4 in N-methylpyrrolidone: a safe alternative for hydride displacement reaction.

Enhanced reactivity of NaBH4 was observed as a solution in N-methylpyrrolidone (NMP). Thus, a simple protocol for debromination of alkyl bromide and sulfonate is devised with NMP as a key solvent. Also described is a new mixed borohydride system, NaBH4-LiOTf-NMP, which works as an alternative to NaBH3CN for the SN2 type displacement. No reports have ever revealed usefulness of NMP in borohydride reduction.

Borohydrides↗

PubMed2001

Arg-735 of the 100-kDa subunit a of the yeast V-ATPase is essential for proton translocation.

The vacuolar (H(+))-ATPases (V-ATPases) are ATP-dependent proton pumps that acidify intracellular compartments and pump protons across specialized plasma membranes. Proton translocation occurs through the integral V(0) domain, which contains five different subunits (a, d, c, c', and c"). Proton transport is critically dependent on buried acidic residues present in three different proteolipid subunits (c, c', and c"). Mutations in the 100-kDa subunit a have also influenced activity, but none of these residues has proven to be required absolutely for proton transport. On the basis of previous observations on the F-ATPases, we have investigated the role of two highly conserved arginine residues present in the last two putative transmembrane segments of the yeast V-ATPase a subunit (Vph1p). Substitution of Asn, Glu, or Gln for Arg-735 in TM8 gives a V-ATPase that is fully assembled but is totally devoid of proton transport and ATPase activity. Replacement of Arg-735 by Lys gives a V-ATPase that, although completely inactive for proton transport, retains 24% of wild-type ATPase activity, suggesting a partial uncoupling of proton transport and ATP hydrolysis in this mutant. By contrast, nonconservative mutations of Arg-799 in TM9 lead to both defective assembly of the V-ATPase complex and decreases in activity of the assembled V-ATPase. These results suggest that Arg-735 is absolutely required for proton transport by the V-ATPases and is discussed in the context of a revised model of the topology of the 100-kDa subunit a.

Adenosine Triphosphate↗

PubMed2001

The amino-terminal domain of the vacuolar proton-translocating ATPase a subunit controls targeting and in vivo dissociation, and the carboxyl-terminal domain affects coupling of proton transport and ATP hydrolysis.

The 100-kDa "a" subunit of the vacuolar proton-translocating ATPase (V-ATPase) is encoded by two genes in yeast, VPH1 and STV1. The Vph1p-containing complex localizes to the vacuole, whereas the Stv1p-containing complex resides in some other intracellular compartment, suggesting that the a subunit contains information necessary for the correct targeting of the V-ATPase. We show that Stv1p localizes to a late Golgi compartment at steady state and cycles continuously via a prevacuolar endosome back to the Golgi. V-ATPase complexes containing Vph1p and Stv1p also differ in their assembly properties, coupling of proton transport to ATP hydrolysis, and dissociation in response to glucose depletion. To identify the regions of the a subunit that specify these different properties, chimeras were constructed containing the cytosolic amino-terminal domain of one isoform and the integral membrane, carboxyl-terminal domain from the other isoform. Like the Stv1p-containing complex, the V-ATPase complex containing the chimera with the amino-terminal domain of Stv1p localized to the Golgi and the complex did not dissociate in response to glucose depletion. Like the Vph1p-containing complex, the V-ATPase complex containing the chimera with the amino-terminal domain of Vph1p localized to the vacuole and the complex exhibited normal dissociation upon glucose withdrawal. Interestingly, the V-ATPase complex containing the chimera with the carboxyl-terminal domain of Vph1p exhibited a higher coupling of proton transport to ATP hydrolysis than the chimera containing the carboxyl-terminal domain of Stv1p. Our results suggest that whereas targeting and in vivo dissociation are controlled by sequences located in the amino-terminal domains of the subunit a isoforms, coupling efficiency is controlled by the carboxyl-terminal region.

Adenosine Triphosphatases↗

PubMed2001

Analysis of codon usage diversity of bacterial genes with a self-organizing map (SOM): characterization of horizontally transferred genes with emphasis on the E. coli O157 genome.

With increases in the amounts of available DNA sequence data, it has become increasingly important to develop tools for comprehensive systematic analysis and comparison of species-specific characteristics of protein-coding sequences for a wide variety of genomes. In the present study, we used a novel neural-network algorithm, a self-organizing map (SOM), to efficiently and comprehensively analyze codon usage in approximately 60,000 genes from 29 bacterial species simultaneously. This SOM makes it possible to cluster and visualize genes of individual species separately at a much higher resolution than can be obtained with principal component analysis. The organization of the SOM can be explained by the genome G+C% and tRNA compositions of the individual species. We used SOM to examine codon usage heterogeneity in the E. coli O157 genome, which contains 'O157-unique segments' (O-islands), and showed that SOM is a powerful tool for characterization of horizontally transferred genes.

Algorithms↗

PubMed2001

Expression and localization of the mouse homologue of the yeast V-ATPase 21-kDa Subunit c" (Vma16p).

We have identified a cDNA encoding the mouse homologue of the yeast V-ATPase 21-kDa subunit c" (Vma16p). The encoded protein contains 205 amino acid residues with five putative membrane spanning segments and shows 48% identity and 64% similarity to the yeast protein. Despite this homology, however, the mouse cDNA does not complement the phenotype of a yeast strain in which the VMA16 gene has been disrupted. Northern blot analysis demonstrated that the 21-kDa subunit is expressed in most tissues examined and showed an expression pattern almost identical to that of the 16-kDa proteolipid subunit (subunit c). The presence of multiple mRNA species suggests the existence of alternatively spliced forms of the 21-kDa subunit which, from Southern blot analysis, are derived from a single gene. Promoter analysis using the luciferase reporter gene revealed that a region 186 bases upstream of the initiation site is sufficient to show a low level of transcriptional activity but that transcription is significantly enhanced by inclusion of the region -186 to -706. The 21-kDa protein was Myc-tagged and the 16-kDa protein was HA-tagged and the tagged proteins were co-expressed in COS-1 cells in order to study their intracellular localization by immunofluorescence microscopy. Both proteins showed significant punctate and perinuclear staining and were predominantly co-localized throughout the cell, consistent with their presence in the same V(0) complexes. Selective permeabilization of cells with digitonin (to permeabilize the plasma membrane) or Triton X-100 (to permeabilize both intracellular and plasma membranes) followed by immunofluorescence microscopy revealed that the carboxyl terminus of the 21-kDa subunit is exposed on the cytoplasmic side of the membrane whereas the carboxyl terminus of the 16-kDa subunit is located on the lumenal side of the membrane.

3T3 Cells↗

PubMed2001

Intratumoral delivery of interleukin 12 expression plasmids with in vivo electroporation is effective for colon and renal cancer.

We report on an antitumor treatment involving electrogene therapy (EGT), a newly developed in vivo gene transfer method using electroporation. We carried out in vivo EGT in a subcutaneous model of CT26 colon carcinoma cells, using plasmid DNAs encoding interleukin 12 (IL-12) subunits. For this purpose, we developed two IL-12 expression systems: a cotransfer system using a plasmid encoding the IL-12 p40 subunit and a plasmid encoding the IL-12 p35 subunit, and a single-vector system using a plasmid expressing a p40-p35 fusion protein. Both transfer systems significantly inhibited the growth of CT26 tumor. Immunohistochemical analysis of IL-12 EGT-treated tumors revealed enhanced infiltration of CD8(+) cells into the tumor tissue, while reverse transcriptase-polymerase chain reaction confirmed the increased expression of interferon gamma within treated tumors. The same IL-12 EGT applied to the nude mouse model was not effective, suggesting the critical role of T cell infiltration in this treatment. The inhibitory effects revealed in experiments in which previously treated mice were rechallenged with a second inoculation of CT26 tumor cells suggested that IL-12 EGT may also establish partial systemic antitumor immunity. The growth of IL-12 EGT-treated Renca tumors, a renal cell carcinoma, was also significantly inhibited. These findings suggest that EGT of the IL-12 gene has the potential to be an effective anticancer gene therapy.

Animals↗

PubMed2001

An efficient conversion of 5-nitroisatin into 5-nitroindole derivative.

Our process research on OPC-35564 revealed that a mixed borohydride reducing agent (ZrCl4/NaBH4) in DME (Itsuno system) afforded a rapid and direct conversion of N-alkyl-nitroisatin into nitroindole nucleus. Comparison with other reducing agents indicated the superiority of the present system and the key function of ZrCl4. For the manipulation of base-labile isatin, a useful procedure for its N-alkylation using Cu2CO3 is also presented.

Alkylation↗

PubMed2001

Yeast V-ATPase complexes containing different isoforms of the 100-kDa a-subunit differ in coupling efficiency and in vivo dissociation.

The 100 kDa a-subunit of the yeast vacuolar (H(+))-ATPase (V-ATPase) is encoded by two genes, VPH1 and STV1. These genes encode unique isoforms of the a-subunit that have previously been shown to reside in different intracellular compartments in yeast. Vph1p localizes to the central vacuole, whereas Stv1p is present in some other compartment, possibly the Golgi or endosomes. To compare the properties of V-ATPases containing Vph1p or Stv1p, Stv1p was expressed at higher than normal levels in a strain disrupted in both genes, under which conditions V-ATPase complexes containing Stv1p appear in the vacuole. Complexes containing Stv1p showed lower assembly with the peripheral V(1) domain than did complexes containing Vph1p. When corrected for this lower degree of assembly, however, V-ATPase complexes containing Vph1p and Stv1p had similar kinetic properties. Both exhibited a K(m) for ATP of about 250 microm, and both showed resistance to sodium azide and vanadate and sensitivity to nanomolar concentrations of concanamycin A. Stv1p-containing complexes, however, showed a 4-5-fold lower ratio of proton transport to ATP hydrolysis than Vph1p-containing complexes. We also compared the ability of V-ATPase complexes containing Vph1p or Stv1p to undergo in vivo dissociation in response to glucose depletion. Vph1p-containing complexes present in the vacuole showed dissociation in response to glucose depletion, whereas Stv1p-containing complexes present in their normal intracellular location (Golgi/endosomes) did not. Upon overexpression of Stv1p, Stv1p-containing complexes present in the vacuole showed glucose-dependent dissociation. Blocking delivery of Vph1p-containing complexes to the vacuole in vps21Delta and vps27Delta strains caused partial inhibition of glucose-dependent dissociation. These results suggest that dissociation of the V-ATPase complex in vivo is controlled both by the cellular environment and by the 100-kDa a-subunit isoform present in the complex.

Enzyme Activation↗