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T Ito

Publications and source records attributed to T Ito.

At least 433 records · Page 24Linked to original sources
PubMed2000

Compensatory coordination of release parameters in a throwing task.

The consistency and coordination of release parameters in ball-throwing movements were investigated. The authors used a newly developed index of coordination for release parameters (ICRP) that quantifies the degree of improvement of performance consistency caused by compensatory relationships among parameters (i.e., not caused by consistency of parameters). Eight participants practiced for 150 trials, with the nondominant hand, a ball-throwing task aimed at a stationary target. The magnitude of the ball-release velocity vector, among release parameters, as well as the performance was found to become consistent with practice. The ICRP score suggested that the release parameters were complementarily coordinated with one another, and that the coordination improved with practice. Those results indicate that compensatory relationships among varying release parameters contribute to reducing the variability of performance in a ball-throwing task whose goal is accuracy.

Adult↗
PubMed2000

Elevation of mRNA levels of tissue-type plasminogen activator and urokinase-type plasminogen activator in hippocampus and cerebral cortex following middle cerebral artery occlusion in rats.

Tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) have been used for thrombolitic therapy. In contrast, it is suggested that these compounds might be involved in neuronal cell damage. The activation and the function of tPA and uPA are less understood in ischemic brain tissue. Therefore, changes in tPA and uPA mRNA in rat brain tissue after MCA occlusion and in the neuronal cell line, PC12 cells, during the hypoxic stimulation were examined. Permanent middle cerebral artery (MCA) occlusion was induced by advancing a filament into the internal carotid artery in 36 adult male Sprague-Dawley rats. The ischemic cerebral cortex and contralateral cortex of MCA area, and bilateral hippocampus were collected at 0 (controls), 1, 3, 6, 12 and 24 h after occlusion. Hypoxia was induced in PC12 cells with a multigas incubator (set to 1% O2). The quantitative reverse transcription-polymerase chain reaction acted as a measurement of alteration in mRNA levels. The mRNA levels of tPA and uPA were significantly increased after MCA occlusion in the ischemic cerebral cortex. The magnitude of the increase in tPA and uPA mRNA in 24 h after occlusion was twice the value in sham-operated rat (0 h). The increases of tPA mRNA were time-dependent in insult and contralateral hippocampus. The increase of uPA mRNA was also seen in the hippocampus bilaterally, although the increase was more significant on the ipsilateral side. In PC12 cells, necrotic (approximately 35%) and apoptotic cells (approximately 65%) could be distinguished by hypoxic stimulus for 24 h, and the mRNA for tPA was significantly increased for 6 h-12 h, while the mRNA for uPA was not detected at any point in the study. Our results suggest that focal ischemia might result in the activation of these proteases not only in the insult but also in the contralateral brain tissue.

Animals↗
PubMed2000

Thymine carboxylation: nucleophilic addition of carbon dioxide radical anion.

PURPOSE: The nucleophilic addition properties of carbon dioxide radical anion (CO2*-) towards N1-substituted thymine derivatives in aqueous solution is studied for comparison with their one-electron reducing reactivity. MATERIAL AND METHODS: N2O-Saturated aqueous solutions of 1-methylthymine, 1,3-dimethylthymine, and thymidylyl(3'-->5')-thymidine containing excess formate ions were gamma-irradiated at 1.0Gy min(-1). Several carboxylated thymines were isolated by preparative HPLC and identified by GC-MS, NMR and X-ray crystallography. RESULTS: Along with one-electron reduction yielding N-substituted 5,6-dihydrothymines and C5--C5'-linked dihydrothymine dimers, the addition of CO2 radical anion(s) to the C5--C6 double bond of N-substituted thymines produced several mono- and di-carboxylic acids, among which N-substituted derivatives of 5,6-dihydrothymine-6-carboxylic acid [5-methyldihydroorotic acid (5-methyl-DHO)] were produced in the highest yield. Similar carboxylation by CO2 radical anions was also observed for thymine dinucleoside monophosphate. The X-ray structure of cis-5,6-dihydro-1-methylthymine-6-carboxylic acid (cis-1,5-dimethyl-DHO) was determined to show a chair conformation in the crystal. CONCLUSIONS: The CO2 radical anion is a nucleophilic radical with rather low reduction potential, thereby possessing a dual reactivity of radical addition preferentially at C6 and one-electron reduction towards thymine-related compounds.

Anions↗
PubMed2000

Differential regulation of metalloproteinase production, proliferation and chemotaxis of human lung fibroblasts by PDGF, interleukin-1beta and TNF-alpha.

Fibroblast migration, proliferation, extracellular matrix protein synthesis and degradation, all of which play important roles in inflammation, are themselves induced by various growth factors and cytokines. Less is known about the interaction of these substances on lung fibroblast function in pulmonary fibrosis. The goal of this study was to investigate the effects of PDGF alone and in combination with IL-1beta and TNF-alpha on the production of human lung fibroblast matrix metalloproteinases, proliferation, and the chemotactic response. The assay for MMPs activity against FITC labeled type I and IV collagen was based on the specificity of the enzyme cleavage of collagen. Caseinolytis and gelatinolytic activities of secreted proteinases were analyzed by zymography. Fibronectin in conditioned media was measured using human lung fibronectin enzyme immunoassay. Cell proliferation was measured by 3H-Thymidine incorporation assay. Cell culture supernatants were tested for PGE2 content by ELISA. Chemotactic activity was measured using the modified Boyden chamber. Matrix metalloproteinase assay indicated that IL-1beta, TNF-alpha and PDGF induced intestitial collagenase (MMP-1) production. MMP assay also indicated that IL-1beta and TNF-alpha had inhibitory effects on MMP-2,9(gelatinaseA,B) production. Casein zymography confirmed that IL-1beta stimulated stromlysin (matrix metalloproteinase 3; MMP-3) and gelatin zymography demonstrated that TNF-alpha induced MMP-9 production in human lung fibroblast, whereas PDGF alone did not. PDGF in combination with IL-1beta and TNF-alpha induced MMP-3 and MMP-9 activity, as demonstrated by zymography. PDGF stimulated lung fibroblast proliferation in a concentration-dependent manner, whereas IL-1beta and TNF-alpha alone had no effect. In contrast, the proliferation of human lung fibroblasts by PDGF was inhibited in the presence of IL-1beta and TNF-alpha, and this inhibition was not a consequence of any elevation of PGE2. PDGF stimulated fibroblast chemotaxis in a concentration-dependent manner, and this stimulation was augmented by combining PDGF with IL-1beta and TNF-alpha. These findings suggested that PDGF differentially regulated MMPs production in combination with cytokines, and further that MMP assay and zymography had differential sensitivity for detecting MMPs. The presence of cytokines with PDGF appears to modulate the proliferation and chemotaxis of human lung fibroblasts.

Cell Division↗
PubMed2000

Effect of heparin and related glycosaminoglycan on PDGF-induced lung fibroblast proliferation, chemotactic response and matrix metalloproteinases activity.

Fibroblast migration, proliferation, extracellular matrix protein synthesis and degradation are the key events in various biological and pathological processes in pulmonary fibrosis. In addition, biopsy specimens from the lungs of patients with pulmonary fibrosis show increased numbers of mast cells which have metachromatic granules containing heparin, histamine and proteases. Little is known about how these products influence pulmonary fibrosis. In the present study, we investigated the effect of heparin and related glycosaminoglycans on PDGF-induced lung fibroblast proliferation and chemotactic response in vitro. In addition, we examined the effect of heparin on both the induction of matrix metalloproteinases (MMPs) and MMPs activity in lung fibroblasts in vitro. Heparin, de-N-sulphated heparin but not heparan sulphate inhibited PDGF-induced lung fibroblast proliferation. In contrast, only heparin inhibited PDGF-stimulated human lung fibroblast chemotaxis. Negatively charged poly-L-glutamic acid had no effect on either fibroblast proliferation or chemotaxis. Thus the negative charge alone cannot account for the ant-proliferative and anti-chemotactic effects of heparin. Furthermore, heparin and heparan sulphate also had no inhibitory effect on induction of MMPS, including MMP-1 (interstitial collagenase), MMP-2 (gelatinase A) and MMP-9 (gelatinase B). Only heparin inhibited both MMP-1 and MMP-2/MMP-9 activity. Additionally, tissue inhibitor of metalloproteinase type 1 (TIMP-1) and type 2 (TIMP-2) inhibited PDGF-stimulated human lung fibroblast chemotaxis. The ability of heparin to inhibit fibroblast chemotaxis may account for the inhibitory effect of heparin on MMP activity. The above results suggested that heparin and related glycosaminoglycans differentially regulate PDGF-induced lung fibroblast proliferation, chemotaxis and MMPs activity and further that these effects may have a key role in extracellular matrix remodeling in inflammatory lung disease.

Becaplermin↗
PubMed2000

Protective effect of inducible type nitric oxide synthase against intracellular oxidative stress caused by advanced glycation end-products in vascular smooth muscle cells from stroke-prone spontaneously hypertensive rats.

OBJECTIVE: A recent study demonstrated that free radicals were involved in the maintenance of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP). However, the role of oxidative stress in hypertension and its related diseases in SHRSP remains unknown. On the other hand, advanced glycation end-products (AGEs) accumulate progressively in the vasculature with ageing, and have been identified to be as relevant mediators for various vascular complications. To elucidate whether nitric oxide (NO) produced by inducible type NO synthase (iNOS) in vascular smooth muscle cells (VSMC) taken from SHRSP and Wistar-Kyoto rats (WKY) attenuate AGEs-induced oxidative stress, we investigated the effect of NO donors and iNOS-induction in VSMC on intracellular oxidant level caused by AGEs. METHODS: The cells preincubated with or without NO donor, S-nitroso-n-acetylpenicillamine (SNAP) or 3-morpholinosydnonimine (SIN-1), IL-1beta and/or N(G)-monomethyl-L-arginine monoacetate (L-NMMA), were treated with AGEs, and the intracellular oxidant levels, total glutathione (GSH) levels, and gamma-glutamylcysteine synthetase (GCS) mRNA were determined. We also determined the expression of an iNOS in VSMC from SHRSP and WKY. RESULTS: The intracellular oxidant level of VSMC was induced by AGEs in a dose-dependent manner. NO donor dose-dependently reduced AGEs-stimulated intracellular oxidant level. Treatment with IL-1beta reduced the AGEs-stimulated intracellular oxidant level through increased NO production, whilst inhibition of NO production by L-NMMA reduced the inhibitory effect of IL-1beta. We also confirmed that NO production as well as the expression of iNOS mRNA and the protein itself were significantly decreased in response to IL-1beta in VSMC from SHRSP compared with WKY. We also confirmed that total GSH levels, decreased by AGEs, were restored by stimulation with IL-1beta. Increased GSH synthesis was due to enhanced expression of the rate-limiting enzyme for GSH synthesis, GCS. These results indicate that NO release, produced by iNOS in VSMC in response to cytokines, might play a protective role against AGEs-stimulated oxidative stress in VSMC. This protective effect of NO is decreased in SHRSP compared to WKY.

Albumins↗
PubMed2000

Ascorbic acid improves postischemic vasodilatation impaired by infusion of soybean oil into canine iliac artery.

This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.

Animals↗
PubMed2000

Nucleotide sequence and genome organization of apple latent spherical virus: a new virus classified into the family Comoviridae.

A virus with isometric virus particles (ca. 25 nm) was isolated from an apple tree and named Apple latent spherical virus (ALSV). Virus particles purified from infected Chenopodium quinoa formed two bands with densities of 1.41 and 1.43 g/cm(3) in CsCl equilibrium density-gradient centrifugation, indicating that the virus is composed of two components. The virus had two ssRNA species (RNA1 and RNA2) and three capsid proteins (Vp25, Vp24 and Vp20). The complete nucleotide sequences of RNA1 and RNA2 were determined to be 6815 nt and 3384 nt excluding the 3' poly(A) tail, respectively. RNA1 contains two partially overlapping ORFs encoding polypeptides of molecular mass 23 kDa ('23K'; ORF1) and 235 kDa ('235K'; ORF2); RNA2 has a single ORF encoding a polypeptide of 108 kDa ('108K'). The 235K protein has, in order, consensus motifs of the protease cofactor, the NTP-binding helicase, the cysteine protease and the RNA polymerase, in good agreement with the gene arrangement of viruses in the COMOVIRIDAE: The 108K protein contains an LPL movement protein (MP) motif near the N terminus. Direct sequencing of the N-terminal amino acids of the three capsid proteins showed that Vp25, Vp20 and Vp24 are located in this order in the C-terminal region of the 108K protein. The cleavage sites of the 108K polyprotein were Q/G (MP/Vp25 and Vp25/Vp20) and E/G (Vp20/Vp24). Phylogenetic analysis of the ALSV RNA polymerase domain showed that ALSV falls into a cluster different from the nepo-, como- and fabavirus lineages.

Amino Acid Sequence↗
PubMed2000

Comparative genome analysis of the mouse imprinted gene impact and its nonimprinted human homolog IMPACT: toward the structural basis for species-specific imprinting.

Mouse Impact is a paternally expressed gene encoding an evolutionarily conserved protein of unknown function. Here we identified IMPACT, the human homolog of Impact, on chromosome 18q11. 2-12.1, a region syntenic to the mouse Impact locus. IMPACT was expressed biallelically in brain and in various tissues from two informative fetuses and in peripheral blood from an informative adult. To reveal the structural basis for the difference in allelic expression between the two species, we elucidated complete genome sequences for both mouse Impact ( approximately 38 kb) and human IMPACT ( approximately 30 kb). Sequence comparison revealed that the two genes share a well-conserved exon-intron organization but bear significantly different CpG islands. The mouse island lies in the first intron and contains characteristic tandem repeats. Furthermore, this island serves as a differentially methylated region (DMR) consisting of a hypermethylated maternal allele and an unmethylated paternal allele. Intriguingly, this intronic island is missing from the nonimprinted human IMPACT, whose sole CpG island spans the first exon, lacks any apparent repeats, and escapes methylation on both chromosomes. These results suggest that the intronic DMR plays a role in the imprinting of Impact.

Alleles↗
PubMed2000

Overexpression of a gene encoding a cytochrome P450, CYP78A9, induces large and seedless fruit in arabidopsis.

An activation tagging screen in which the cauliflower mosaic virus 35S enhancer was inserted randomly into an Arabidopsis genome homozygous for the floral homeotic mutation apetala2-1 (ap2-1) resulted in a line (28-5) with extraordinarily wide, heart-shaped ovaries. The ovary of the 28-5 ap2-1 mutant shows an oval shape because of increased numbers of enlarged cells. When the ap2-1 mutation is crossed out of the genetic background, more elongated rather than wider fruits are obtained. Normally, Arabidopsis fruits will develop to a normal size only when the ovules are present and fertilized. In the 28-5 single mutant, the siliques keep growing despite failure of fertilization and can reach nearly normal size. When wild-type pollen was used to pollinate the mutant pistil, the pollinated 28-5 silique became >10% longer and 40% wider than a wild-type silique, although producing very few seeds. The enhancer insertion in line 28-5 acts by hyperactivating a cytochrome P450 gene, CYP78A9. The pistil of 28-5 ap2-1 mutant flowers shows a structure similar to that of Capsella bursa-pastoris, a distant mustard relative of Arabidopsis, suggesting that the processes regulated by the CYP78A9-encoded protein may be involved in evolutionary control of carpel shape.

Arabidopsis↗
PubMed2000

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Explore the source record for details and available documents.

Journal Article↗
PubMed2000

Effect of the sialyl Lewis X (SLe(x)) moiety on splenic accumulation of SLe(x)-carboxymethylpullulan conjugate.

Sialyl Lewis X (SLe(x)), an E-selectin ligand, was conjugated with carboxymethylpullulan (CMPul) and the disposition characteristics of this conjugate after intravenous administration were investigated using mice with ear edema. The concentration of 3H-labeled SLe(x)-CMPul in the spleen was significantly high. When CMPul was modified with a saccharide unable to bind to E-selectin, this splenic accumulation was not observed. The uptake of radiolabeled SLe(x)-CMPul by the spleen was completely inhibited by a 100-fold molar of cold SLe(x)-CMPul but not by a sialyl N-acetyllactosamine-CMPul conjugate (SLN-CMPul). Microautoradiography analyses revealed that SLe(x)-CMPul accumulated in the marginal zone of the spleen.

Animals↗
PubMed2000

[Influenza virus surveillance in Tama, Tokyo--viral examinations in 1996/97, 1997/98, 1998/99, and 1999/2000 seasons].

During the 1996/97, 1997/98, 1998/99, and 1999/2000 seasons, isolations of influenza virus and/or confirmations of hemagglutinin gene of virus from the throat swab of patients in 9 medical institutions in Tama, Tokyo were carried out by RT-PCR and tissue culture with MDCK cells. In 1996/97 and 1997/98 seasons, type A (H3N2) was the predominant type of influenza virus, which was 85% in the 1996/97 and 97% in the 1997/98, but small-scale outbreaks with type B virus was also confirmed in the 1996/97 season (during the 8th and 10th week). On the other hand, in the other two seasons, 2 different kinds of types of virus were discovered, which was type A (H3N2) and type B in 1998/99 season, and H3N2 and H1N1 of type A virus in 1999/2000 season. In the 1998/99 season, type A (H3N2) prevailed in the first half, and type B gradually replaced type A (H3N2) after the 5th week in 1999, whereas 2 different kinds of type A in the 1999/2000 mixed during the outbreak. From the presented data, the difference of mode by age groups and year could be explained. Namely, most specimens and positive cases in 1996/97 and 1997/98 seasons were those from low age groups (fifteen years of age and below). In 1998/99 and 1999/2000 seasons, the number of specimens from high age groups (sixteen years of age or over) accounted for above 50%, and about 70% of type A (H3N2)-positive cases. Contrary, the frequency of type B virus in 1998/99 season and type A (H1N1) in 1999/2000 season was higher in the low age groups than the high ones.

Hemagglutination, Viral↗
PubMed2000

A new class of genetic element, staphylococcus cassette chromosome mec, encodes methicillin resistance in Staphylococcus aureus.

We have previously shown that the methicillin-resistance gene mecA of Staphylococcus aureus strain N315 is localized within a large (52-kb) DNA cassette (designated the staphylococcal cassette chromosome mec [SCCmec]) inserted in the chromosome. By sequence determination of the entire DNA, we identified two novel genes (designated cassette chromosome recombinase genes [ccrA and ccrB]) encoding polypeptides having a partial homology to recombinases of the invertase/resolvase family. The open reading frames were found to catalyze precise excision of the SCCmec from the methicillin-resistant S. aureus chromosome and site-specific as well as orientation-specific integration of the SCCmec into the S. aureus chromosome when introduced into the cells as a recombinant multicopy plasmid. We propose that SCCmec driven by a novel set of recombinases represents a new family of staphylococcal genomic elements.

Amino Acid Sequence↗
PubMed2000

Pulsed-field gel electrophoresis-based molecular comparison of vibrio cholerae O1 isolates from domestic and imported cases of cholera in Japan.

Sixty-seven Vibrio cholerae O1 El Tor isolates (36 domestic and 31 imported) were classified into 19 subtypes by NotI- and SfiI-digested pulsed-field gel electrophoresis. Twenty-five of 36 domestic and 4 imported isolates were assigned to a NotI-A1-SfiI-A1 subtype, suggesting that this pulse type is widely distributed in Asia and Japan.

Bacterial Typing Techniques↗
PubMed2000

New Ehrlichia species closely related to Ehrlichia chaffeensis isolated from Ixodes ovatus ticks in Japan.

Seven Ehrlichia strains (six HF strains and one Anan strain) that were obtained from laboratory mice by intraperitoneally inoculating homogenates of adult Ixodes ovatus collected in Japan were characterized. 16S rRNA sequences of all six HF strains were identical, and the sequences were 99.7, 98.2, and 97.7% identical to those of Anan strain, Ehrlichia chaffeensis (human monocytic ehrlichiosis agent), and E. muris, respectively. Partial GroEL amino acid sequencing also revealed that the six HF strains had identical sequences, which were 99.0, 98.5, and 97.3% identical to those of E. chaffeensis, the Anan strain, and E. canis, respectively. All HF strains were lethal to mice at higher dosages and intraperitoneal inoculation, whereas the Anan or E. muris strain induced only mild clinical signs. Light and electron microscopy of moribund mice inoculated with one of the HF strains revealed severe liver necrosis and the presence of numerous ehrlichial inclusions (morulae) in various organs. The study revealed that members of E. canis genogroup are naturally present in Ixodes ticks. HF strains that can cause severe illness in immunocompetent laboratory mice would be valuable in studying the pathogenesis and the roles of both cellular and humoral immune responses in ehrlichiosis caused by E. canis genogroup.

Amino Acid Sequence↗