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Biomedical subjects

K Nishi

Publications and source records attributed to K Nishi.

At least 19 recordsLinked to original sources
PubMed2001

LIGHT, a member of the TNF superfamily, induces morphological changes and delays proliferation in the human rhabdomyosarcoma cell line RD.

LIGHT is a member of the tumor necrosis factor (TNF) superfamily, which binds two known receptors, lymphotoxin-beta receptor (LTbetaR) and the herpesvirus entry mediator (HVEM)/TR2. We investigated the effects of LIGHT on the human rhabdmyosarcoma cell line RD. LIGHT delayed cell proliferation and induced morphological changes of the cells. These effects were not shown by other TNF family ligands such as TNFalpha and LTalpha, which induced the transcriptional activity of nuclear factor-kappaB (NF-kappaB) and NF-kappaB-responsible chemokine productions in the same manner as did LIGHT. LTalpha1beta2, another TNF family ligand for LTbetaR, was shown to have similar activities in RD cells as LIGHT. Both LIGHT and LTalpha1beta2 induced the expression of muscle-specific genes such as smooth muscle (SM) alpha-actin, while TNFalpha and LTalpha did not. These findings indicate that LIGHT may be a novel inducer of RD cell differentiation associated with SM alpha-actin expression through the LTbetaR.

Actins↗
PubMed2001

Subthalamo-pallido-striatal axis: a feedback system in the basal ganglia.

Systemic administration of a dopamine D2 receptor blocker, haloperidol, but not vehicle, significantly increased the number of c-Fos-immunoreactive neurons in the globus pallidus (GP) in rats. Dual immunohistochemistry, a combination of c-Fos immunohistochemistry and retrograde tracing experiments with cholera toxin B (ChB), revealed that a subset of the c-Fos-immunoreactive GP neurons was pallidostriatal feedback neurons. Lesioning of the subthalamic nucleus (STN) by local injection of ibotenic acid inhibited the haloperidol-induced c-Fos expression in the GP neurons, suggesting that the activation of GP neurons is a result of increased excitatory drives from the STN. Therefore, the present findings are evidence of the existence of the subthalamo-pallido-striatal axis as a feedback system in the internal circuits of the basal ganglia.

Animals↗
PubMed2001

Molecular monitoring of bleomycin-induced pulmonary fibrosis by cDNA microarray-based gene expression profiling.

Pulmonary fibrosis is a progressive disorder whose molecular pathology is poorly understood. Here we developed an in-house cDNA microarray ("lung chip") originating from a lung-normalized cDNA library. By using this lung chip, we analyzed global gene expression in a murine model of bleomycin-induced fibrosis and selected 82 genes that differed by more than twofold intensity in at least one pairwise comparison with controls. Cluster analysis of these selected genes showed that the expression of genes associated with inflammation reached maximum levels at 5 days after bleomycin administration, while genes involved in the development of fibrosis increased gradually up to 14 days after bleomycin treatment. These changes in gene expression signature were well correlated with observed histopathological changes. The results show that microarray analysis of animal disease models is a powerful approach to understanding the gene expression programs that underlie these disorders.

Animals↗
PubMed2001

Fluorescence intermittency in self-assembled InP quantum dots.

Fluorescence intermittency in InP self-assembled dots is investigated by means of far field imaging and single dot spectroscopy. Based on our observation that blinking dots are found in the vicinity of scratches and the blinking frequency is drastically enhanced under a near-infrared laser irradiation, we attribute the origin of the fluorescence intermittency to a local electric field due to a carrier trapped at a deep localized center in the Ga0.5In0.5P matrix. The validity of this explanation is confirmed by a thermal activation-type behavior of the switching rate and artificial reproduction of the blinking phenomenon by an external electric field.

Journal Article↗
PubMed2001

Pyrrolidine inhibitors of human cytosolic phospholipase A2. Part 2: synthesis of potent and crystallized 4-triphenylmethylthio derivative 'pyrrophenone'.

We synthesized a potent and crystallized human cytosolic phospholipase A2alpha inhibitor, pyrrophenone (6) which inhibits the isolated enzyme with an IC50 value of 4.2 nM. Pyrrophenone shows potent inhibition of arachidonic acid release, prostaglandin E2, thromboxane B2, and leukotriene B4 formation in human whole blood. The magnitudes of prostaglandin E2 and thromboxane B2 inhibition are the same as those of indomethacin.

Arachidonic Acid↗
PubMed2001

The cyclin-dependent kinase (CDK) inhibitor flavopiridol inhibits glycogen phosphorylase.

Flavopiridol has been shown to induce cell cycle arrest and apoptosis in various tumor cells in vitro and in vivo. Using immobilized flavopiridol, we identified glycogen phosphorylases (GP) from liver and brain as flavopiridol binding proteins from HeLa cell extract. Purified rabbit muscle GP also bound to the flavopiridol affinity column. GP is the rate-limiting enzyme in intracellular glycogen breakdown. Flavopiridol significantly inhibited the AMP-activated GP-b form of the purified rabbit muscle isoenzyme (IC50 of 1 microM at 0.8 mM AMP), but was less inhibitory to the active phosphorylated form of GP, GP-a (IC50 of 2.5 microM). The AMP-bound GP-a form was poorly inhibited by flavopiridol (40% at 10 microM). Increasing concentrations of the allosteric effector AMP resulted in a linear decrease in the GP-inhibitory activity of flavopiridol suggesting interference between flavopiridol and AMP. In contrast the GP inhibitor caffeine had no effect on the relative GP inhibition by flavopiridol, suggesting an additive effect of caffeine. Flavopiridol also inhibited the phosphorylase kinase-catalyzed phosphorylation of GP-b by inhibiting the kinase in vitro. Flavopiridol thus is able to interfere with both activating modifications of GP-b, AMP activation and phosphorylation. In A549 NSCLC cells flavopiridol treatment caused glycogen accumulation despite of an increase in GP activity, suggesting direct GP inhibition in vivo rather than inhibition of GP activation by phosphorylase kinase. These results suggest that the cyclin-dependent kinase inhibitor flavopiridol interferes with glycogen degradation, which may be responsible for flavopiridol's cytotoxicity and explain its resistance in some cell lines.

Adenosine Monophosphate↗
PubMed2001

Functional annotation of a full-length mouse cDNA collection.

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Animals↗
PubMed2001

Both the conserved and the unique gene structure of stomach-specific calpains reveal processes of calpain gene evolution.

The proteins nCL-2 and nCL-2' are members of the Ca2+-dependent cysteine protease (calpain) superfamily, with stomach-specific expression. Like other typical calpains, nCL-2 has three distinct domains, a protease, a C2-like, and a 5EF-hand Ca2+-binding domain, as well as the N-terminal propeptide region. On the other hand, nCL-2' lacks the C2-like and 5EF-hand domains but is otherwise identical to nCL-2, except for the three C-terminal residues. To examine the stomach-specific and presumed alternative expression mechanisms of nCL-2 and nCL-2', we have cloned and characterized the mouse gene for nCL-2 and nCL-2'. The mouse nCL-2 gene contains at least 23 exons, spanning more than 50 kb, and possesses an exon specific for nCL-2' in the middle. Therefore, nCL-2 and nCL-2' are generated by alternative splicing of the same gene, Capn8. Capn8 shows the highly conserved gene organization of the other typical calpain large subunit genes, CAPN1, CAPN2, CAPN3, CAPN9, CAPN11, and Capn12, except for the unique exon between exon 9 and exon 10 of Capn8, which encodes the 3' half of the nCL-2' transcript. No such exon in the corresponding regions was found in CAPN1, CAPN2, CAPN3, CAPN9, or CAPN11. Gene and cDNA structures of a presumed human orthologue of mouse nCL-2, CAPN8, were determined, revealing that it overlaps human CAPN2, the gene for the m-calpain large subunit, in head-to-head orientation at 1q32-41. These features of Capn8 and CAPN8 illustrate a process of calpain gene evolution, i.e., the protease, C2-like, and 5EF-hand domains presumably functioned as independent genes, and the calpain superfamily has evolved by ordered fusions of these ancestral gene units, with subsequent amplifications.

Alternative Splicing↗
PubMed2001

Effect of round-edged acrylic intraocular lenses on preventing posterior capsule opacification.

PURPOSE: To clarify the extent to which the adhesiveness of an acrylic material influences the formation of posterior capsule opacification (PCO). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: Two types of AcrySof(R) intraocular lenses (IOLs) were prepared: round edged and tumbled. The AcrySof with round edges was implanted in 1 eye in a group of 4 rabbits and the tumbled IOL, in 1 eye in a group of 5 rabbits. In both groups, the contralateral eye received a conventional AcrySof with sharp optic edges. A histopathological examination was performed 3 weeks after surgery. RESULTS: With the round-edged AcrySof IOL, no capsular bend formed at the optic edge and abundant lens epithelial cells (LECs) migrated posteriorly. With the sharp-edged AcrySof lens, a sharp capsular bend formed and LEC migration was significantly inhibited. In eyes with a tumbled IOL, a capsular bend was created, but it was less marked than that created by the sharp-edged lens and there was slightly more LEC migration posteriorly. CONCLUSIONS: The AcrySof IOL lost its preventive effect on PCO when the optic was rounded. The effect of the AcrySof lens in preventing PCO is mainly a result of its rectangular, sharp-edged optic design. The acrylic material may play a complementary role by helping create a sharp capsular bend. Capsular bend formation is the key to the PCO preventive effect of an IOL.

Acrylic Resins↗
PubMed2001

Capsular bending ring to prevent posterior capsule opacification: 2 year follow-up.

PURPOSE: To evaluate the preventive effect of a capsular bending ring on anterior and posterior capsule (PCO) opacification in a 2 year clinical study. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: This study comprised 60 patients with senile cataract (35 women, 25 men) with a mean age of 69 years. An open poly(methyl methacrylate) capsular bending ring with a truncated edge profile designed to create a sharp bend in the equatorial capsule was implanted in 1 eye of patients with a hydroxyethyl methacrylate intraocular lens (IOL). The contralateral eye, which acted as a control, received an IOL but no ring. Patients were examined 6 months (n = 52), 1 year (n = 48), and 2 years (n = 42) postoperatively. Anterior capsule opacification was determined by slitlamp evaluation. Anterior capsule shrinkage (area within the capsulorhexis) and PCO were evaluated and scored using a computer software package for image analysis. Posterior capsule opacification was also measured by the rate of neodymium:YAG (Nd:YAG) capsulotomies. RESULTS: Anterior capsule opacification and shrinkage were significantly less in eyes with the ring. The mean PCO score was 0.235 +/- 0.215 (SD), 0.287 +/- 0.200, and 0.398 +/- 0.248 with the ring and 0.530 +/- 0.190, 0.670 +/- 0.225, and 1.111 +/- 0.298 without the ring at 6 months, 1 year, and 2 years, respectively (P <.01 at each follow-up). An Nd:YAG laser capsulotomy was performed in 4 eyes with and 17 eyes without the ring after 2 years (P <.01). CONCLUSIONS: The capsular bending ring significantly reduced anterior capsule fibrosis and shrinkage as well as PCO. The ring may be useful in patients who are at high risk of developing eye complications from capsule opacification that require Nd:YAG laser capsulotomy, in those expected to have vitreoretinal surgery and photocoagulation, and in cases of pediatric cataract.

Aged↗
PubMed2001

Selective expression of erg isoforms in human endothelial cells.

Erg and Fli-1 are closely related members of the ets family of transcription factors. There are at least five human Erg isoforms (Erg-1, Erg-2, Erg-3/p55(Erg), p49(Erg) and p38(Erg)) produced through differential mRNA splicing and alternative use of translational start codons. However, relatively little is known about the expression or function of these isoforms in vitro or their distribution in vivo. We used RT-PCR to screen a panel of primary and established human cell lines for erg and fli-1 consensus sequences. Whilst fli-1 was expressed in several human cell types, erg was detected mainly in endothelial cells. To identify which erg isoforms are expressed in endothelial cells we used RT-PCR, Northern blotting and 5'-RACE. Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like transcripts were detected in both microvascular and large vessel endothelial cells affinity-purified from different vascular beds. Moreover, these erg isoforms were present in both freshly isolated, and confluent endothelial cells following several passages in culture, indicating that endothelial erg expression in vitro may be broadly representative of that in vivo. The selective expression of the Erg-3/p55(Erg) and p38(Erg)/p38(Erg)-like isoforms in endothelial cells indicates their involvement in the regulation of endothelial-restricted genes.

Base Sequence↗
PubMed2001

The properties of ryanodine-sensitive Ca(2+) release in mouse gastric smooth muscle cells.

1. Under voltage-clamped conditions, gastric smooth muscle cells of BALB/c mice developed spontaneous (STOCs) and caffeine- (I(CAF)) and carbachol-induced (I(CCh)) transient outward currents. 2. In fura-2 microscopic measurements of intracellular Ca(2+) concentration ([Ca(2+)](i)), caffeine and carbachol (CCh) provoked similar transient [Ca(2+)](i) elevations. 3. Both I(CCh) and CCh-induced [Ca(2+)](i) elevation of single smooth muscle cells occurred in an 'all-or-nothing' fashion in contrast to the reproducible caffeine responses. 4. On the basis of the suppression of STOCs and I(CAF) by nicardipine, tetraethylammonium and iberiotoxin, but not by charybdotoxin nor apamin, it was suggested that both currents were generated by large conductance type Ca(2+)-activated K(+) channels. 5. In measurements of isometric tension, caffeine produced relaxation of gastric smooth muscle strips in a concentration-dependent manner (0.1 -- 3 mM). The concentration-dependent relaxation with caffeine was mimicked by dibutyryl cyclic AMP which produced potentiation of contraction triggered by 50 mM KCL. 6. At caffeine concentrations >3 mM, a transient contraction followed by relaxation was provoked as the quasi maximal response to caffeine. In the quasi maximal response, caffeine acted as a potent relaxant in smooth muscle strips precontracted with 50 mM KCl or 3 microM CCh. 7. The relaxation with caffeine was significantly accelerated in those strips precontracted with KCl or CCh. All these results suggest that ryanodine-sensitive Ca(2+) release, which is triggered by caffeine, is an important modifier of Ca(2+) homeostasis in the cytoplasm and the contractility of gastric smooth muscle cells of mice.

Animals↗
PubMed2001

Near-field spectroscopy of single quantum dots at room temperature.

The observation of photoluminescence spectra of self-assembled single InGaAs quantum dots at room temperature was performed under weak excitation conditions using a near-field scanning optical microscope. Operation in illumination-collection mode with a highly sensitive double-tapered optical fibre probe enabled detection of weak photoluminescence signals at room temperature with high efficiency and high spatial resolution. Each single quantum dot was imaged with a spatial resolution of about 250 nm, which corresponded to a quarter of the wavelength of the photoluminescence from quantum dots. The photoluminescence yields of individual quantum dots were widely distributed and were found to decrease with photoluminescence energy. This result serves as a clue to be pursued for better understanding of the thermal excitation of the carrier from confined states in quantum dots.

Journal Article↗
PubMed2001

Inhibition of lens epithelial cells by Fas-specific antibody activating Fas-Fas ligand system.

PURPOSE: To detect cell specific apoptosis factors, Fas and Fas ligand, and the common intracellular apoptosis modulators, interleukin-1 beta converting enzyme (ICE)-like protease (caspase 1), Bcl-2, Bcl-xL and Bax in lens epithelial cells (LEC) of human cataracts. To study the effects of Fas-stimulating monoclonal antibody on inhibition of LEC proliferation. METHODS: Reverse-transcriptase-polymerase chain reaction (RT-PCR) was used to detect Fas, Fas ligand, caspase 1, Bcl-2, Bcl-xL and Bax, after cDNA was synthesized from the total RNA isolated from human cataractous LEC obtained by capsulotomy during cataract surgery. Fas-stimulating monoclonal antibody was added at the concentrations of 10, 30, 100, 300 and 1000 ng/ml to the incubation medium of human cataractous LEC; and the specimens were incubated for 24 h at 37 degrees C with 5% CO(2) circulation and 100% humidity. The specimens were then stained with Hoechst 33342, and the number of apoptotic cells was counted. RESULTS: Fas, caspase 1, Bcl-2, Bcl-xL and Bax mRNA were detected by RT-PCR. Fas ligand mRNA was not detected by RT-PCR. At each concentration, Fas-stimulating monoclonal antibody significantly inhibited LEC proliferation. CONCLUSIONS: Human cataractous LEC expressed mRNA of Fas and various modulators of apoptosis pathways. Fas-stimulating monoclonal antibody may have the potential to prevent posterior capsule opacification after cataract surgery by inhibiting LEC proliferation.

Aged↗
PubMed2001

Purification, molecular cloning, and immunohistochemical localization of dipeptidyl peptidase II from the rat kidney and its identity with quiescent cell proline dipeptidase.

We purified dipeptidyl peptidase II (DPP II) to homogeneity from rat kidney and determined its physicochemical properties, including its molecular weight, substrate specificity, and partial amino acid sequence. Furthermore, we screened a rat kidney cDNA library, isolated the DPP II cDNA and determined its structure. The cDNA was composed of 1,720 base pairs of nucleotides, and 500 amino acid residues were predicted from the coding region of cDNA. Human quiescent cell proline dipeptidase (QPP) cloned from T-cells is a 58-kDa glycoprotein existing as a homodimer formed with a leucine zipper motif. The levels of amino acid homology were 92.8% (rat DPP II vs. mouse QPP) and 78.9% (rat DPP II vs. human QPP), while those of nucleotide homology were 93.5% (rat DPP II vs. mouse QPP) and 79.4% (rat DPP II vs. human QPP). The predicted amino acid sequences of rat DPP II and human and mouse QPP possess eight cysteine residues and a leucine zipper motif at the same positions. The purified DPP II showed similar substrate specificity and optimal pH to those of QPP. Consequently, it was thought that DPP II is identical to QPP. Northern blot analysis with rat DPP II cDNA revealed prominent expression of DPP II mRNA in the kidney, and the order for expression was kidney >> testis > or = heart > brain > or = lung > spleen > skeletal muscle > or = liver. In parallel with Northern blot analysis, the DPP II antigen was detected by immunohistochemical staining in the cytosol of epithelial cells in the kidney, testis, uterus, and cerebrum.

Amino Acid Sequence↗
PubMed2001

Mutation of an arginine biosynthesis gene causes reduced pathogenicity in Fusarium oxysporum f. sp. melonis.

Restriction enzyme-mediated integration (REMI) mutagenesis was used to tag genes required for pathogenicity of Fusarium oxysporum f. sp. melonis. Of the 1,129 REMI transformants tested, 13 showed reduced pathogenicity on susceptible melon cultivars. One of the mutants, FMMP95-1, was an arginine auxotroph. Structural analysis of the tagged site in FMMP95-1 identified a gene, designated ARG1, which possibly encodes argininosuccinate lyase, catalyzing the last step for arginine biosynthesis. Complementation of FMMP95-1 with the ARG1 gene caused a recovery in pathogenicity, indicating that arginine auxotrophic mutation causes reduced pathogenicity in this pathogen.

Arginine↗
PubMed2001

Carotid endarterectomy with external shunt: a new device and indication for use: technical note.

OBJECTIVE: We designed a new external shunt system and evaluated its indications and efficacy in patients undergoing carotid endarterectomy (CEA). METHODS: In 8 of 332 CEA procedures, external shunts were placed between the common carotid artery and the internal carotid artery (ICA). This procedure was implemented for one of two indications: 1) a change in electroencephalographic and/or somatosensory evoked potential readings immediately after ICA occlusion, or 2) elongation of the ICA made safe insertion of an internal shunt impossible. In addition, a shunt was placed between the common carotid artery and the external carotid artery to establish collateral circulation from the external carotid artery to the intracranial circulation, which is essential during ICA occlusion. RESULTS: All external shunts were functional, and electroencephalography and somatosensory evoked potentials demonstrated no significant abnormalities during the CEAs. All patients awoke from surgery without manifestation of new neurological deficits. CONCLUSION: Our new external shunt device proved safe and efficacious in cases that did not permit the placement of an internal shunt.

Aged↗