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S Ito

Publications and source records attributed to S Ito.

At least 19 recordsLinked to original sources
PubMed2007

Anodic oxidation and hydrothermal treatment of commercially pure titanium surfaces increases expression of bone morphogenetic protein-2 in the adherent macrophage cell line J774A.1.

The surface property of commercially pure titanium (cpTi) was improved by forming a thin hydroxyapatite (HA) layer by anodic oxidation and hydrothermal treatment (HA/cpTi). We hypothesize that the adhesion of macrophages to HA/cpTi surfaces is important to the process of osseointegration. This study investigates the effect of adhesion of macrophages to HA/cpTi surfaces on the expression of bone morphogenetic protein-2 (BMP-2). The murine macrophage cell line J774A.1 was cultured on HA/cpTi and polished cpTi (S/cpTi). Macrophage cell adhesion was examined by SEM, 0-72 h following plating onto HA/cpTi and S/cpTi. BMP-2 gene expression was examined by RT-PCR analysis. The level of BMP-2 secreted into the supernatant was measured using an ELISA assay. The extent of macrophage adhesion increased with time on both the HA/cpTi and S/cpTi surfaces, with a" higher degree of spreading observed on HA/cpTi than onS/cpTi surfaces after 24 or 72 h. The ratio of BMP-2 mRNA was higher on HA/cpTi than on S/cpTi after 24 h (0.348 vs. 0, p < 0.05) and 72 h (0.584 vs. 0.189, p < 0.05). After 24 h, secretion of BMP-2 was detected in cultures grown on HA/cpTi, but not on S/cpTi. After 72 h, secretion of BMP-2 was detected in cultures grown on S/cpTi, but the levels were higher in cultures grown on HA/cpTi. These findings show that macrophages have the capacity to adhere to HA/cpTi endosseous implants and provide a source of osteoinductive cytokines that may play a key role in the process of osseointegration.

Animals↗
PubMed2006

T-type Ca2+ channels mediate propagation of odor-induced Ca2+ transients in rat olfactory receptor neurons.

Propagation of odor-induced Ca(2+) transients from the cilia/knob to the soma in mammalian olfactory receptor neurons (ORNs) is thought to be mediated exclusively by high-voltage-activated Ca(2+) channels. However, using confocal Ca(2+) imaging and immunocytochemistry we identified functional T-type Ca(2+) channels in rat ORNs. Here we show that T-type Ca(2+) channels in ORNs also mediate propagation of odor-induced Ca(2+) transients from the knob to the soma. In the presence of the selective inhibitor of T-type Ca(2+) channels mibefradil (10-15 microM) or Ni(2+) (100 microM), odor- and forskolin/3-isobutyl-1-methyl-xanthine (IBMX)-induced Ca(2+) transients in the soma and dendrite were either strongly inhibited or abolished. The percentage of inhibition of the Ca(2+) transients in the knob, however, was 40-50% less than that in the soma. Ca(2+) transients induced by 30 mM K(+) were partially inhibited by mibefradil, but without a significant difference in the extent of inhibition between the knob and soma. Furthermore, an increase of as little as 2.5 mM in the extracellular K(+) concentration (7.5 mM K(+)) was found to induce Ca(2+) transients in ORNs, and such responses were completely inhibited by mibefradil or Ni(2+). Total replacement of extracellular Na(+) with N-methyl-d-glutamate inhibited none of the odor-, forskolin/IBMX- or 7.5 mM K(+)-induced Ca(2+) transients. Positive immunoreactivity to the Ca(v)3.1, Ca(v)3.2 and Ca(v)3.3 subunits of the T-type Ca(2+) channel was observed throughout the soma, dendrite and knob. These data suggest that involvement of T-type Ca(2+) channels in the propagation of odor-induced Ca(2+) transients in ORNs may contribute to signal transduction and odor sensitivity.

1-Methyl-3-isobutylxanthine↗
PubMed2006

Urinary retention can be the sole initial manifestation of acute myelitis.

Urinary retention is a frequent feature in patients with acute myelitis (AM). We here describe the result of a survey of 32 consecutive AM patients as to what extent of AM patients initially present with micturition disturbance. Among those, 3 patients (9%) were shown to have urinary retention as the initial sole manifestation, which was followed by dysesthesia of foot in 3 and leg weakness in 1; and the average interval between micturition disturbance and these second-appearing symptoms/signs was 11 days (8-15 days). Although initial presentation of urinary retention was not common, occurring in only 9% of all the AM patients, clinically it has relevance because patients who suffer urinary retention but have no obvious neurological symptoms may first see general physicians or urologists. In those patients, when obstructive disease has been excluded, AM should be considered.

Acute Disease↗
PubMed2006

Effects of intracerebroventricular infusions of arginine vasopressin in sheep.

In sheep, neither the in vivo effect of vasopressin administered by a method other than systemic infusion nor the central effects on behavior from the perspective of stress regulation has been fully elucidated in an intact animal. We examined changes in behavioral, adrenocorticotropic, and autonomic nervous functions after intracerebroventricular infusions of arginine vasopressin (AVP) to elucidate its central role. Intracerebroventricular infusions of AVP (0, 0.12, 1.2 and 12 microg/500 microl/30 min) evoked a dose-related increase in plasma cortisol concentration. There were significant treatment-related effects on the total duration of sham-chewing (Friedman's test, X2=12.75, p=.0052), on the total duration of bar-biting (Friedman's test, X2=15.0, p=.0018), and on the total duration of rubbing (Friedman's test, X2=12.0, p=.0074). AVP 12 microg treatment induced a greater degree of sham-chewing and bar-biting than the other three treatments did (Nemenyi multiple comparisons: p<0.1). These findings indicate, together with our previous findings, that AVP has the same corticotropic potential as corticotropin-releasing hormone infused intracerebroventricularly in equal molar concentrations. Although the degree to which central stress signaling pathways are involved in these responses remains speculative, the relationships between stereotypies and central AVP are of particular interest.

Animals↗
PubMed2006

Cardinium symbionts cause cytoplasmic incompatibility in spider mites.

Intracellular symbiotic bacteria belonging to the Cytophaga-Flavobacterium-Bacteroides lineage have recently been described and are widely distributed in arthropod species. The newly discovered bacteria, named Cardinium sp, cause the expression of various reproductive alterations in their arthropod hosts, including cytoplasmic incompatibility (CI), induction of parthenogenesis and feminization of genetic males. We detected 16S ribosomal DNA sequences similar to those of Cardinium from seven populations of five spider mite species, suggesting a broad distribution of infection of Cardinium in spider mites. To clarify the effect of Cardinium on the reproductive traits of the infected spider mites, infected mites were crossed with uninfected mites for each population. In one of the populations, Eotetranychus suginamensis, CI was induced when infected males were crossed with uninfected females. The other six populations of four species showed no reproductive abnormalities in the F(1) generation, but the possibility of CI effects in the F(2) generation remains to be tested. One species of spider mite, Tetranychus pueraricola, harbored both Cardinium and Wolbachia, but these symbionts seemed to have no effect on the reproduction of the host, even when the host was infected independently with each symbiont.

Animals↗
PubMed2006

Synthesis, characterization, and DFT-TDDFT computational study of a ruthenium complex containing a functionalized tetradentate ligand.

A ruthenium complex trans-[Ru(L)(NCS)2], L = 4,4' ''-di-tert-butyl-4',4' '-bis(carboxylic acid)-2,2':6',2' ':6' ',2' ''-quaterpyridine (N886), was synthesized and characterized by spectroscopic and electrochemical methods. The absorption spectrum of the N886 complex shows metal-to-ligand charge-transfer transitions in the entire visible region and quasi-reversible oxidation and reduction potentials at E(1/2) = +0.38 and -1.92 V vs ferrocene, respectively. The electronic spectra of the N886 complex were calculated by density functional theory (DFT)-time-dependent DFT, which qualitatively reproduces the experimental absorption spectra for both the protonated and deprotonated species. From the analysis of the computed optical transitions of N886, we assign its absorption bands as mixed Ru/SCN-to-quaterpyridine charge-transfer transitions, which extend from the near-IR to the UV regions. The panchromatic response of the N886 complex renders it as a suitable sensitizer for solar energy conversion applications based on titanium dioxide mesoporous electrodes. The preliminary results using the N886 complex as a sensitizer in a dye-sensitized solar cell, with an electrolyte containing 0.60 M butylmethylimidazolium iodide, 0.03 M I2, and 0.50 M tert-butylpyridine in a mixture of acetonitrile and valeronitrile (volume ratio 1:1), show 40% incident photon-to-current efficiencies, yielding under standard AM 1.5 sunlight a short-circuit photocurrent density of 11.8 +/- 0.2 mA/cm(2), an open-circuit voltage of 680 +/- 30 mV, and a fill factor of 0.73 +/- 0.03, corresponding to an overall conversion efficiency of 5.85%.

Journal Article↗
PubMed2006

v-Src requires Ras signaling for the suppression of gap junctional intercellular communication.

Cell transformation by v-Src causes suppression of gap junctional intercellular communication (GJIC). Although tyrosine phosphorylation of connexin43 (Cx43), a gap junctional component, appears to be necessary for the suppression, involvement of other signaling remains unclear. We investigated the role of Ras signaling in the suppression of GJIC by v-Src. Conditional expression of either S17N Ras or mtGap1m dramatically recovered GJIC in v-Src-transformed cells. Although expression of S17N Ras or mtGap1m substantially decreased the levels of active Ras, tyrosine phosphorylation of cellular proteins including Cx43 remained unchanged. Similarly, treatment of v-Src-transfomed cells with a Ras farnesyltransferase inhibitor, manumycin A, restored GJIC, whereas tyrosine phosphorylation of Cx43 remained unchanged. Thus, these results strongly suggest that, in addition to Cx43 phosphorylation, constitutive activation of Ras signaling is required for the suppression of GJIC by v-Src.

Animals↗
PubMed2006

Superconductivity of doped Ar@C60.

The synthesis of a mg amount of pure argon containing fullerene allowed the synthesis of the first endohedral superconductors with critical temperatures lower than expected, an indication of the strong influence of the argon atom on the C60 cage.

Journal Article↗
PubMed2006

Hematopoietic stem cell transplantation for 30 patients with primary immunodeficiency diseases: 20 years experience of a single team.

We retrospectively analyzed our results of 30 patients with three distinctive primary immunodeficiency diseases (PIDs)--severe combined immunodeficiency (SCID, n = 11), Wiskott-Aldrich syndrome (WAS, n = 11) and X-linked hyper-immunoglobulin M (IgM) syndrome (XHIM, n = 8)--who underwent hematopoietic SCT (HSCT) during the past 20 years. Until 1995, all donors were HLA-haploidentical relatives with T-cell depletion (TCD) (n = 8). Since 1996, the donors have been HLA-matched related donors (MRD) (n = 8), unrelated BM (UR-BM) (n = 7) and unrelated cord blood (UR-CB) (n = 7). Twenty-seven of 30 patients had various pre-existing infections with or without organ damages before HSCT. Conditioning regimen and GVHD prophylaxis were determined according to disease, donor and pretransplant status. Although one of eight patients transplanted with TCD is alive with full engraftment, the other seven died. On the other hand, 18 of 22 patients transplanted without TCD are alive and well, including six of eight transplanted from MRD, seven of seven from UR-BM and five of seven from UR-CB. All 19 survivors did not require Ig supplementation after HSCT. These results indicate that UR-CBT as well as UR-BMT provides good results for PID comparable to MRD-SCT, and that early diagnosis, HSCT at early stage, careful supportive therapy and monitoring for various pathogens are important for the successful HSCT.

Adolescent↗
PubMed2006

Involvement of reduced sensitivity to Ca in beta-adrenergic action on airway smooth muscle.

BACKGROUND: It is well known that beta-adrenoceptor agonists (beta-agonists) cause relaxation in airway smooth muscle mediated by a reduction in the concentration of intracellular Ca2+ ([Ca2+](i)). However, little is currently known regarding whether reduced sensitization to Ca2+ is involved in the beta-adrenergic relaxation. OBJECTIVE: This study was designed to determine the intracellular mechanisms underlying suppression of Ca2+ sensitization in beta-adrenergic relaxation (Ca(2+)-independent relaxation by beta-agonists). Methods Isometric tension and [Ca2+](i) were simultaneously measured in fura-2-loaded strips isolated from guinea-pig tracheal smooth muscles. The relationships between tension and [Ca2+](i) were examined in the inhibitory action of isoprenaline (ISO) and other cAMP-related agents against methacholine-induced contraction. RESULTS: The concentration-inhibition curve for ISO against methacholine in tension was significantly dissociated from the curve for ISO in [Ca2+](i). In ISO-induced relaxation, a reduction in tension was significantly greater than that in [Ca2+](i.) This phenomenon was mimicked by other cAMP-related agents: forskolin and dibutyryl-cAMP. In contrast, the inhibitory action of SKF-96365, a non-selective inhibitor of Ca(2+) channels, was associated with that in [Ca2+](i). In the presence of Rp-cAMPS, an inhibitor of protein kinase A (PKA), ISO caused an equivalent relaxation with less reduction in [Ca2+](i). The effects of ISO were not affected by Y-27632, an inhibitor of Rho-kinase, or by bisindolylmaleimide, an inhibitor of protein kinase C. ISO failed to inhibit contraction elicited by calyculin A, an inhibitor of myosin phosphatase. Conclusion beta-Adrenergic action antagonizes not only Ca2+ mobilization but also Ca2+ sensitization in methacholine-induced contraction. The cAMP/PKA-independent, G(s)-direct action is more potent in Ca(2+)-independent relaxation by beta-agonists than the cAMP/PKA-dependent pathway. Moreover, myosin phosphatase is a fundamentally affected protein in the reduced response to Ca2+ mediated by beta-agonist. Our results may provide evidence that this Ca2+ desensitization is a novel target for a reliever medication using rapid-acting beta-agonists in acute asthma management.

Adrenergic beta-Agonists↗
PubMed2006

Glomerulonephritis in children with mixed connective tissue disease.

AIMS: Mixed connective tissue disease (MCTD) has overlapping clinical features with systemic lupus erythematosus (SLE). Renal biopsy is necessary for all children with SLE to evaluate the prognosis, because they are at a quite high risk of developing renal complications. Furthermore, lupus nephritis and hypocomplementemia usually precede the appearance of clinical manifestations. Immune complex-mediated nephritis is one of the major complications of MCTD. Juvenile MCTD is known to be associated with a higher risk of nephritis than adult MCTD. However, it is uncertain whether all children with MCTD should be subjected to a renal biopsy, and whether most of those with hypocomplementemia present nephropathy, as in patients with SLE. We examined the histopathological characteristics of juvenile MCTD nephritis, the importance of renal biopsy and the implications of hypocomplementemia in our patients and reported cases of MCTD. MATERIAL AND METHODS: We performed renal biopsy in 11 children with MCTD and found 6 patients with glomerulonephritis. In addition, we studied the frequency and the characteristics of glomerulonephritis in 71 cases of juvenile MCTD (our 11 patients and 60 reported cases). We also analyzed the relationship between hypocomplementemia and pathological features in 41 cases of MCTD nephritis (23 adults, 18 children). RESULTS: 6 of our 11 patients had glomerulonephritis, but of them four had no abnormality in urinalysis at the time of biopsy. In 5 patients renal biopsy showed normal findings. Review of 71 cases of juvenile MCTD showed that of them 28% presented latent asymptomatic nephritis at the time of biopsy. Membranous nephropathy (MN) and mesangial proliferative glomerulonephritis (MPG) were common in MCTD. Interestingly, hypocomplementemia was more frequently observed in patients with MN or mixed form of MN and MPG (MPG/MN) than simple MPG based on our review of 41 cases (p < 0.01). CONCLUSION: A more aggressive indication of renal biopsy should be considered in children with MCTD because of the high incidence of non-clinical nephritis. The hypocomplementemia observed in patients with MCTD suggests the high frequency of glomerulonephritis, including membranous lesions.

Adolescent↗
PubMed2005

Zinc modulates primary afferent fiber-evoked responses of ventral roots in neonatal rat spinal cord in vitro.

Zinc ions (Zn(2+)) are known to modulate the functions of a variety of channels, receptors and transporters. We examined the effects of Zn(2+) on the reflex potentials evoked by electrical stimulation and responses to depolarizing agents in the isolated spinal cord of the neonatal rat in vitro. Zn(2+) at low concentrations (0.5-2 microM) inhibited, but at high concentrations (5 and 10 microM) augmented, a slow depolarizing component (slow ventral root potential). Zn(2+) had no effect on fast components (monosynaptic reflex potential; fast polysynaptic reflex potential). Unlike Zn(2+), strychnine (5 microM), a glycine receptor antagonist, and (S),9(R)-(-)-bicuculline methobromide (10 microM), a GABA(A) receptor antagonist, potentiated both fast polysynaptic reflex potential and slow ventral root potential. Zn(2+) (5 microM) did not affect depolarizing responses to glutamate and N-methyl-D-aspartate. Zn(2+) enhanced the substance P-evoked depolarization in the absence of tetrodotoxin (0.3 microM) but not in its presence. The dorsal root potential was inhibited by (S),9(R)-(-)-bicuculline methobromide (10 microM) but not by Zn(2+) (5 microM). The Zn(2+)-potentiated slow ventral root potential was inhibited by the N-methyl-D-aspartate receptor antagonists, ketamine (10 microM) and DL-2-amino-5-phosphaonovaleric acid (50 microM) but not by P2X receptor antagonists, pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (30 microM) and 2',3'-O-(2,4,6-trinitrophenyl)ATP (10 microM). Ketamine (10 microM) and DL-2-amino-5-phosphaonovaleric acid (50 microM) almost abolished spontaneous activities increased by Zn(2+). It is concluded that Zn(2+) potentiated slow ventral root potential induced by primary afferent stimulation, which was mediated by the activation of N-methyl-D-aspartate receptors but not by activation of P2X receptors or blockade of glycinergic and GABAergic inhibition. Zn(2+) does not seem to directly affect N-methyl-D-aspartate receptors. The release of glutamate from interneurons may play an important role in Zn(2+)-induced potentiation of slow ventral root potential in the spinal cord of the neonatal rat.

Animals↗