Showing papers by "Chonbuk National University published in 2000"
TL;DR: Findings indicate that the Tie2 receptor, PI 3'-kinase, and Akt are crucial elements in the signal transduction pathway leading to endothelial cell survival induced by the paracrine activity of Ang1.
Abstract: Angiopoietin-1 (Ang1) is a strong apoptosis survival factor for endothelial cells. In this study, the receptor/second messenger signal transduction pathway for the antiapoptotic effect of Ang1 on human umbilical vein endothelial cells was examined. Pretreatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the Ang1-induced antiapoptotic effect. Ang1 induced phosphorylation of Tie2 and the p85 subunit of phosphatidylinositol 3'-kinase (PI 3'-kinase) and increased PI 3'-kinase activity in a dose-dependent manner. The PI 3'-kinase-specific inhibitors wortmannin and LY294002 blocked the Ang1-induced antiapoptotic effect. Ang1 induced phosphorylation of the serine-threonine kinase Akt at Ser473 in a PI 3'-kinase-dependent manner. Expression of a dominant-negative form of Akt reversed the Ang1-induced antiapoptotic effect. Ang1 mRNA and protein were present in vascular smooth muscle cells but not in endothelial cells. Cultured vascular smooth muscle cells, but not human umbilical vein endothelial cells, secreted Ang1. These findings indicate that the Tie2 receptor, PI 3'-kinase, and Akt are crucial elements in the signal transduction pathway leading to endothelial cell survival induced by the paracrine activity of Ang1.
620 citations
363 citations
TL;DR: Findings indicate that at high concentrations, Ang2, like Ang1, can be an apoptosis survival factor for endothelial cells through the activation of the Tie2 receptor, PI 3′-kinase and Akt, and thus may be a positive regulator of tumor angiogenesis.
Abstract: The angiopoietin-Tie2 system in endothelial cells is an important regulator of vasculogenesis and vascular integrity. High levels of angiopoietin-2 (Ang2) mRNA are observed in vascular activation during tumorigenesis. Although Ang2 is known to be a naturally occurring antagonist of angiopoietin-1 (Ang1) in vivo, the exact function of Ang2 itself is not known. Here, we found that a high concentration of Ang2 (800 ng/ml) acts as an apoptosis survival factor for endothelial cells during serum deprivation apoptosis. The survival effect of high concentration Ang2 was blocked by pre-treatment with soluble Tie2 receptor and the PI 3'-kinase-specific inhibitors, wortmannin and LY294002. Accordingly, 800 ng/ml of Ang2 induced phosphorylation of Tie2, the p85 subunit of phosphatidylinositol 3'-kinase (PI 3'-kinase), and serine-threonine kinase Akt at Ser473 in the human umbilical vein endothelial cells; lower concentrations of Ang2 (50 - 400 ng/ml) did not produce notable effects. These findings indicate that at high concentrations, Ang2, like Ang1, can be an apoptosis survival factor for endothelial cells through the activation of the Tie2 receptor, PI 3'-kinase and Akt, and thus may be a positive regulator of tumor angiogenesis. Oncogene (2000) 19, 4549 - 4552.
338 citations
TL;DR: Two kinds of adaptive control schemes for robot manipulator which has the parametric uncertainties are presented and the proposed controllers are robust not only to the structured uncertainty such as payload parameter, but also to the unstructured one such as friction model and disturbance.
Abstract: This paper presents two kinds of adaptive control schemes for robot manipulator which has the parametric uncertainties. In order to compensate these uncertainties, we use the FLS (fuzzy logic system) that has the capability to approximate any nonlinear function over the compact input space. In the proposed control schemes, we need not derive the linear formulation of robot dynamic equation and tune the parameters. We also suggest the robust adaptive control laws in all proposed schemes for decreasing the effect of approximation error. To reduce the number of fuzzy rules of the FLS, we consider the properties of robot dynamics and the decomposition of the uncertainty function. The proposed controllers are robust not only to the structured uncertainty such as payload parameter, but also to the unstructured one such as friction model and disturbance. The validity of the control scheme is shown by computer simulations of a two-link planar robot manipulator.
308 citations
TL;DR: Angiopoietin-1-induced sprouting activity in endothelial cells may be accomplished by cytoskeletal changes and secretion of proteinases and may be largely mediated through intracellular PI 3'-kinase activation.
Abstract: Angiopoietin-1 (Ang1) is a strong inducer of endothelial cell sprouting, which is a first step in both angiogenesis and neovascularization. We examined the mechanisms underlying Ang1-induced cell sprouting using porcine pulmonary artery endothelial cells. Ang1 induced the nondirectional and directional migration of endothelial cells mediated through the Tie2 but not the Tie1 receptor. Ang1 induced tyrosine phosphorylation of p125(FAK), and this phosphorylation was dependent on phosphatidylinositol (PI) 3'-kinase activity. Ang1 induced the secretion of plasmin and matrix metalloproteinase-2 (MMP-2), which is inhibited by PI 3'-kinase inhibitors. Ang1 also induced the secretion of small amounts of proMMP-3 and proMMP-9 but not proMMP-1. Ang1 suppressed the secretion of tissue inhibitor of metalloproteinase-2 (TIMP-2), but not of TIMP-1. Addition of alpha(2)-antiplasmin, a combination of TIMP-1 and TIMP-2, or PI 3'-kinase inhibitors inhibited Ang1-induced sprouting activity. Therefore, Ang1-induced sprouting activity in endothelial cells may be accomplished by cytoskeletal changes and secretion of proteinases and may be largely mediated through intracellular PI 3'-kinase activation.
262 citations
TL;DR: Recombinant HFARP acts as an apoptosis survival factor for vascular endothelial cells, but does not bind to Tie1 or Tie2 (endothelial-cell tyrosine kinase receptors).
Abstract: Using degenerate PCR we isolated a cDNA encoding a novel 406- and 410-amino acid protein from human and mouse embryonic cDNAs and have designated it ‘hepatic fibrinogen/angiopoietin-related protein’ (HFARP). The N-terminal and C-terminal portions of HFARP contain the characteristic coiled-coil domains and fibrinogen-like domains that are conserved in angiopoietins. In human and mouse tissues, HFARP mRNA is specifically expressed in the liver. HFARP mRNA and protein are mainly present in the hepatocytes. HFARP has a highly hydrophobic region at the N-terminus that is typical of a secretory signal sequence and one consensus glycosylation site. Recombinant HFARP expressed in COS-7 cells is secreted and glycosylated. HFARP protein is present not only in the hepatocytes, but also in the circulating blood. Recombinant HFARP acts as an apoptosis survival factor for vascular endothelial cells, but does not bind to Tie1 or Tie2 (endothelial-cell tyrosine kinase receptors). These results suggest that HFARP may exert a protective function on endothelial cells through an endocrine action.
248 citations
TL;DR: In this article, the authors performed density-functional-based tight-binding calculations to search for adsorption sites and predict the maximum hydrogen storage capacity in carbon nanotubes.
202 citations
TL;DR: The Big Five factors have been used in psycholexical studies of personality structure in several languages as mentioned in this paper, in addition to variants of the Big Five factor, a sixth factor that has been given names suggesting honesty, suc...
Abstract: Psycholexical studies of personality structure in several languages have recovered, in addition to variants of the Big Five factors, a sixth factor that has been given names suggesting honesty, suc...
200 citations
TL;DR: In this article, the authors examined the relative importance of three pricing factors for American Depository Receipts (ADRs): the price of the underlying shares in the local currency, the relevant exchange rate, and the US market index.
Abstract: This paper extends previous research by considering three pricing factors for American Depository Receipts (ADRs): the price of the underlying shares in the local currency, the relevant exchange rate, and the US market index. Using both a vector autoregressive (VAR) model with a cointegration constraint and a seemingly-unrelated regression (SUR) approach, we examine the relative importance of, and the speed of adjustment of ADR prices to, these underlying factors. Our results show that while the price of the underlying shares is most important, the exchange rate and the US market also have an impact on ADR prices. While the bulk of the shocks to the pricing factors are reflected in the ADRs within the same calendar day, there are indications that the adjustments are not completed until the following day. Curiously, the ADRs appear to initially overreact to the US market index but underreact to changes in underlying share prices and exchange rates.
178 citations
TL;DR: In this paper, the contact resistance between a carbon nanotube and metal electrodes decreases by several orders of magnitude and becomes long-term stable when the nanotubes contacted by Ti-Au electrodes was annealed by a rapid thermal annealing method at 600-800 °C for 30 s.
Abstract: The contact resistance between a carbon nanotube and metal electrodes decreases by several orders of magnitude and becomes long-term stable when the nanotube contacted by Ti-Au electrodes was annealed by a rapid thermal annealing method at 600-800 °C for 30 s. The contact resistances of the annealed samples are in the range 0.5-50 kΩ at room temperature, depending on the electrical properties of the nanotube. The short and relatively low-temperature annealing process enables us to make a surface Ti-nanotube contact suitable for electrical measurements. For the samples with relatively low contact resistances (0.5-5 kΩ) at room temperature, the contact resistance remained constant or decreased slightly as the temperature was lowered. Those with a relatively high contact resistance (5-50 kΩ), on the other hand, showed increasing contact resistance with a lowering of the temperature.
177 citations
TL;DR: The data suggest that staurosporine-induced apoptosis in osteoblasts may occur via activation of JNK1, caspase-3-like proteases, and transcriptional factors including AP-1 and NF- kappa B.
TL;DR: It is suggested that carbon nanotubes can survive selectively during the oxidative etching process with a precise control of annealing temperature, in good agreement with experimental results of purification process of carbon Nanotubes.
Abstract: Adsorption and desorption of an oxygen molecule on carbon nanotubes are investigated using density functional calculations. Several precursor states exist at the edge of armchair nanotubes, whereas an exothermic adsorption takes place at the edge of zigzag nanotubes. We also estimate desorption barriers of a CO molecule from nanotubes as well as fullerenes and amorphous phases. Our calculations suggest that carbon nanotubes can survive selectively during the oxidative etching process with a precise control of annealing temperature, in good agreement with experimental results of purification process of carbon nanotubes.
TL;DR: It was observed that the ECs were adhered more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions.
TL;DR: It has been observed that the SOTS gives fairly comparable in vitro release features as that of commercialized push-pull osmotic tablet system, such as an approximately constant rate up to 24 h and independence of release media and agitation rate.
TL;DR: Genotypic profile and clinicopathologic features of nasal‐type natural killer (NK)/T‐cell lymphoma of nasal and extranasal origin and NK precursor lymphoma are defined and described.
Abstract: BACKGROUND
This study aimed to define genotypic profile and to describe the clinicopathologic features of nasal-type natural killer (NK)/T-cell lymphoma of nasal and extranasal origin and NK precursor lymphoma.
METHODS
NK/T-cell lymphomas from the upper aerodigestive tract (n = 45), skin (n = 2), gastrointestinal tract (n = 3), and soft tissue (n = 2) and NK precursor neoplasms (n = 3) were studied. Immunophenotype was analyzed by immunohistochemistry and flow cytometry. In situ hybridization with EBER 1/2 RNA probes was performed. T-Cell Receptor (TCR)–γ gene rearrangement was analyzed by seminested polymerase chain reaction with heteroduplex analysis. Overall survival rate was correlated with clinicopathologic parameters and compared by Wilcoxon test.
RESULTS
Clonal TCR-γ gene rearrangement was detected in 3 of 31 upper aerodigestive and 1 of 2 skin tumors. When immunostained using paraffin embedded tissue, 6 upper aerodigestive lymphomas were negative for CD56 in which 4 cases lacked clonal TCR gene rearrangement. Epstein–Barr virus (EBV) mRNA was detected in 33 upper aerodigestive tumors including 26 of 29 nasal tumors (90%), and 7 of 10 extranasal tumors (70%). There was no histologic, immunophenotypic, or genotypic differences according to the lineage and EBV association in upper aerodigestive lymphomas. Among the patients with upper aerodigestive tumors, overall 1-year survival rate was 41%, and correlated well with the stage (P 0.05). Median survival rate of lymphomas from other sites excluding upper aerodigestive tract was not significantly different from that of upper aerodigestive lymphomas with same stage (P > 0.05). Unlike nasal-type NK/T-cell lymphomas, NK precursor lymphoma involved the bone marrow and lymph nodes at initial presentation or in the course of disease. Tumor cells were positive for TdT in all and myeloid markers in two. TCR gene rearrangement was germ line.
CONCLUSIONS
Most upper aerodigestive nasal-type NK/T-cell lymphomas among Koreans are genotypically of NK derivation and few belong to T lineage. Presence or absence of EBV has no significant correlation with the histologic changes and the lineage of these lymphomas. Cancer 2000;89:2106–16. © 2000 American Cancer Society.
TL;DR: In this article, the authors investigated the atomic and electronic structures of threading edge dislocations of GaN using self-consistent charge density-functional tight-binding approaches.
Abstract: We investigate atomic and electronic structures of the threading edge dislocations of GaN using self-consistent-charge density-functional tight-binding approaches. Full-core, open-core, Ga-vacancy, and N-vacancy edge dislocations are fully relaxed in our total-energy scheme. The Ga-vacancy dislocation is the most stable in a wide range of Ga chemical potentials, whereas full-core and open-core dislocations are more stable than others in the Ga-rich region. Partial dehybridization takes place during the lattice relaxation near the dislocation in all cases. The dangling bonds at Ga atoms mostly contribute to the deep-gap states, whereas those at N atoms contribute to the valence-band tails. All the edge dislocations can act as deep trap centers, except the Ga-vacancy dislocation, which may act as an origin of yellow luminescence.
01 Jan 2000
TL;DR: In this paper, the authors defined genotypic profile and described the clinicopathologic features of nasal-type natural killer (NK)/T-cell lymphoma of nasal and extranasal origin and NK precursor lymphoma.
Abstract: BACKGROUND. This study aimed to define genotypic profile and to describe the clinicopathologic features of nasal-type natural killer (NK)/T-cell lymphoma of nasal and extranasal origin and NK precursor lymphoma. METHODS. NK/T-cell lymphomas from the upper aerodigestive tract (n = 45), skin (n = 2), gastrointestinal tract (n = 3), and soft tissue (n = 2) and NK precursor neoplasms (n = 3) were studied. Immunophenotype was analyzed by immunohistochemistry and flow cytometry. In situ hybridization with EBER 1/2 RNA probes was performed. T-Cell Receptor (TCR)-y gene rearrangement was analyzed by seminested polymerase chain reaction with heteroduplex analysis. Overall survival rate was correlated with clinicopathologic parameters and compared by Wilcoxon test. RESULTS. Clonal TCR-y gene rearrangement was detected in 3 of 31 upper aerodigestive and 1 of 2 skin tumors. When immunostained using paraffin embedded tissue, 6 upper aerodigestive lymphomas were negative for CD56 in which 4 cases lacked clonal TCR gene rearrangement. Epstein-Barr virus (EBV) mRNA was detected in 33 upper aerodigestive tumors including 26 of 29 nasal tumors (90%), and 7 of 10 extranasal tumors (70%). There was no histologic, immunophenotypic, or genotypic differences according to the lineage and EBV association in upper aerodigestive lymphomas. Among the patients with upper aerodigestive tumors, overall 1-year survival rate was 41%, and correlated well with the stage (P 0.05). Median survival rate of lymphomas from other sites excluding upper aerodigestive tract was not significantly different from that of upper aerodigestive lymphomas with same stage (P > 0.05). Unlike nasal-type NK/T-cell lymphomas, NK precursor lymphoma involved the bone marrow and lymph nodes at initial presentation or in the course of disease. Tumor cells were positive for TdT in all and myeloid markers in two. TCR gene rearrangement was germ line. CONCLUSIONS. Most upper aerodigestive nasal-type NK/T-cell lymphomas among Koreans are genotypically of NK derivation and few belong to T lineage. Presence or absence of EBV has no significant correlation with the histologic changes and the lineage of these lymphomas.
TL;DR: During the cloning of genes for VEGF related proteins, a mouse cDNA that can encode for a protein of 345 amino acids is isolated and a comparison of the amino acid sequence reveals that this predicted gene product displays 95% identity to human PDGF-C.
TL;DR: This paper presents the reverse jacket transform [RJT] and a simple decomposition of its matrix, which is used to develop a fast algorithm for the RJT, and represents in particular the systematical block-wise sparse matrix of extending-method for [J]/sub N/.
Abstract: This paper presents the reverse jacket transform [RJT] and a simple decomposition of its matrix, which is used to develop a fast algorithm for the RJT. The matrix decomposition is of the form of the matrix products of Hadamard matrices and successively lower order coefficient matrices. This decomposition very clearly leads to a block circular sparse matrix factorization of the reverse jacket [RJ]/sub N/ matrix. The main property of [RJ]/sub N/ is that the inverse matrices of its elements can be obtained very easily and have a special structure. [RJ]/sub N/ is derived using the weighted Hadamard transform corresponding to the Hadamard matrix [H]/sub N/ and a basic symmetric matrix /spl Lambda/. Each element of [RJ]/sub N/ is a generalized for polygonal subsampling and canonical Smith form. In this paper we represent in particular the systematical block-wise sparse matrix of extending-method for [RJ]/sub N/.
TL;DR: Results suggest that TNF-α-induced inflammatory angiogenesis might be facilitated by the induction of Ang2, an important regulator of vasculogenesis and vascular integrity.
TL;DR: Results indicate that, in endothelial cells, LPS can directly enhance angiogenesis by inducing MMP-2 activation mediated through an NF-kappaB pathway.
TL;DR: The monolithic osmotic tablet system was found to be able to deliver nifedipine at the rate of approximate zero-order up to 24 h, independent of both environmental media and agitation rate, and substantially comparable with the push-pull osmotics tablet.
TL;DR: Ang1 promotes the survival of endothelial cells in irradiation- and mannitol-induced apoptosis through Tie2 receptor binding and PI3-kinase activation, and could be beneficial in maintaining normal endothelial cell integrity during intracoronary irradiation or systemicMannitol therapy.
Abstract: Background and Purpose—Angiopoietin-1 (Ang1) is a vasculogenic factor that signals through the endothelial cell–specific Tie2 receptor tyrosine kinase. We recently reported that Ang1 prevented apoptosis induced by serum deprivation in endothelial cells. In this study, we examined whether Ang1 prevents apoptosis in endothelial cells treated with irradiation or clinical concentrations of mannitol. Methods and Results—Ang1 prevented irradiation- and mannitol-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Pretreatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the antiapoptotic effect of Ang1. Two phosphatidylinositol 3′-kinase (PI3-kinase)–specific inhibitors, wortmannin and LY294002, blocked the Ang1-induced antiapoptotic effect. The antiapoptotic potency of Ang1 was similar to or greater than that of vascular endothelial growth factor, basic fibroblast growth factor, and endothelin-1. Ang1 also prevented apoptosis in cultured endothelial cells from p...
TL;DR: In this article, a new spinel material, oxysulfide, has been synthesized using a sol-gel method, and the cathode fabricated using the material shows the capacities of 89.5, 125, and 196 mAh/g in the 4 V (4.3 to 3.5 V) and both the 3 and 4 V regions, respectively.
Abstract: A new spinel material, oxysulfide , has been synthesized using a sol‐gel method. The cathode fabricated using the material shows the capacities of 89.5, 125, and 196 mAh/g in the 4 V (4.3 to 3.0 V), 3 V (2.4 to 3.5 V) and both the 3 and 4 V regions (4.3 to 2.4 V), respectively. This material exhibits no capacity loss after 30 cycles in both the 3 and 4 V regions during cycling. It was found that S doping was very effective in suppressing the formation of the tetragonal phase of in potential ranges of 2.4 to 4.3 V. © 2000 The Electrochemical Society. All rights reserved.
TL;DR: Examination of the effects on the pulmonary circulation and lung fluid balance of different ventilation strategies using large versus small inflation volumes in an animal model of bronchopulmonary dysplasia found chronic lung injury from prolonged mechanical ventilation after premature birth inhibits the normal postnatal decrease in pulmonary vascular resistance and leads to lung edema from increased fluid filtration pressure.
Abstract: Chronic lung disease of early infancy, or bronchopulmonary dysplasia, is a frequent complication of prolonged mechanical ventilation after premature birth. Pulmonary hypertension and edema are common features of this condition, which is often attributed to long-term, repetitive overinflation of incompletely developed lungs. The overall objective of this work was to examine the effects on the pulmonary circulation and lung fluid balance of different ventilation strategies using large versus small inflation volumes in an animal model of bronchopulmonary dysplasia. We studied 16 newborn lambs that were delivered prematurely (124 ± 3 d gestation, term = 147 d) by cesarean section and mechanically ventilated for 3 to 4 wk. Ten lambs were ventilated at 20 breaths/min, yielding a tidal volume of 15 ± 5 mL/kg, and six lambs were ventilated at 60 breaths/min, yielding a tidal volume of 6 ± 2 mL/kg. All lambs received surfactant at birth and had subsequent surgery for closure of the ductus arteriosus and catheter placement to allow serial measurements of pulmonary vascular resistance and lung lymph flow. Chronic lung injury, documented by serial chest radiographs and postmortem pathologic examination, developed in all lambs irrespective of the pattern of assisted ventilation. Pulmonary vascular resistance, which normally decreases during the month after birth at term, did not change significantly from the first to the last week of study. Lung lymph flow, an index of net transvascular fluid filtration, increased with time in lambs that were ventilated at 20 breaths/min, but not in lambs ventilated at 60 breaths/min. Lymph protein concentration decreased with time, indicative of increased fluid filtration pressure, without evidence of a change in lung vascular protein permeability. Postmortem studies showed interstitial lung edema, increased pulmonary arteriolar smooth muscle and elastin, decreased numbers of small pulmonary arteries and veins, and decreased capillary surface density in distal lung of chronically ventilated lambs compared with control lambs that were killed either 1 d (same postconceptional age) or 3 wk (same postnatal age) after birth at term. Thus, chronic lung injury from prolonged mechanical ventilation after premature birth inhibits the normal postnatal decrease in pulmonary vascular resistance and leads to lung edema from increased fluid filtration pressure. These abnormalities of the pulmonary circulation may contribute to the abnormal respiratory gas exchange that often exists in infants with bronchopulmonary dysplasia.
TL;DR: Results suggest that polymorphisms of the ecNOS gene, but not the ACE gene, may be associated with the development of lung cancer.
Abstract: The objectives of this study were to examine the possible involvement of endothelial nitric oxide synthase (ecNOS) and angiotensin-converting enzyme (ACE) genes in the genetic basis of lung cancer. Two hundred eighteen patients with lung cancer and 121 healthy subjects were included in this study. The ecNOS and ACE genotypes were determined in all subjects by polymerase chain reaction. The distribution of genotypes of ecNOS gene was significantly different in the lung cancer group than in the control population. ACE genotype distribution was not significantly different in the lung cancer group compared with the control group. These results suggest that polymorphisms of the ecNOS gene, but not the ACE gene, may be associated with the development of lung cancer.
TL;DR: Corn steep liquor which is commonly used in bioindustry is a good alternative substrate for high priced glucose for the hybrid promoter and suggests a cost effective means for commercial mass production of GO using recombinant yeast.
TL;DR: In this article, the crystal structure of nanowires was determined by multi-channel X-ray diffractometry (MC-XRD), FT-Raman spectroscopy and transmission electron microscopy (TEM).
TL;DR: Analysis of distribution patterns of the major vascular gap junction proteins in the murine kidney suggests that the abundance of Cx40-containing gap junctions may be important for coordinating function of cells within individual blood vessels, while their absence in juxtaglomerular regions of the arterioles may prevent conduction of signals between the glomerulus and afferent or efferent arteriols.