2,134 research outputs found

    Comparative analysis of the JAK/STAT signaling through erythropoietin receptor and thrombopoietin receptor using a systems approach

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    <p>Abstract</p> <p>Background</p> <p>The Janus kinase-signal transducer and activator of transcription (JAK/STAT) pathway is one of the most important targets for myeloproliferative disorder (MPD). Although several efforts toward modeling the pathway using systems biology have been successful, the pathway was not fully investigated in regard to understanding pathological context and to model receptor kinetics and mutation effects.</p> <p>Results</p> <p>We have performed modeling and simulation studies of the JAK/STAT pathway, including the kinetics of two associated receptors (the erythropoietin receptor and thrombopoietin receptor) with the wild type and a recently reported mutation (JAK2V617F) of the JAK2 protein.</p> <p>Conclusion</p> <p>We found that the different kinetics of those two receptors might be important factors that affect the sensitivity of JAK/STAT signaling to the mutation effect. In addition, our simulation results support clinically observed pathological differences between the two subtypes of MPD with respect to the JAK2V617F mutation.</p

    Korea's developmental program for superconductivity

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    Superconductivity research in Korea was firstly carried out in the late 70's by a research group in Seoul National University (SNU), who fabricated a small scale superconducting magnetic energy storage system under the financial support from Korea Electric Power Company (KEPCO). But a few researchers were involved in superconductivity research until the oxide high Tc superconductor was discovered by Bednorz and Mueller. After the discovery of YBaCuO superconductor operating above the boiling point of liquid nitrogen (77 K)(exp 2), Korean Ministry of Science and Technology (MOST) sponsored a special fund for the high Tc superconductivity research to universities and national research institutes by recognizing its importance. Scientists engaged in this project organized 'High Temperature Superconductivity Research Association (HITSRA)' for effective conducting of research. Its major functions are to coordinate research activities on high Tc superconductivity and organize the workshop for active exchange of information. During last seven years the major superconductivity research has been carried out through the coordination of HITSRA. The major parts of the Korea's superconductivity research program were related to high temperature superconductor and only a few groups were carrying out research on conventional superconductor technology, and Korea Atomic Energy Research Institute (KAERI) and Korea Electrotechnology Research Institute (KERI) have led this research. In this talk, the current status and future plans of superconductivity research in Korea will be reviewed based on the results presented in interim meeting of HITSRA, April 1-2, 1994. Taejeon, as well as the research activity of KAERI

    Oral propranolol therapy in 23 infants with infantile hemangioma

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    Background Infantile hemangioma (IH) is a common vascular tumor in pediatric patients, and is commonly treated with propranolol. We describe our experiences with dosage, response to treatment, and side effects in 23 IH patients treated with propranolol. Methods For this nonrandomized comparative cohort study, the authors enrolled 23 patients treated with propranolol. Photographs were taken before propranolol administration and at 3, 6, 9, and 12 months after treatment. Treatment responses were objectively analyzed with a computer program. Results There were three male and 20 female patients. Common tumor locations were the head and neck (13 cases, 56.5%), trunk (four cases, 17.4%), extremities (three cases, 13.0%), and combined locations (three cases, 13.0%). The response to propranolol was significantly lower in patients with two or more lesions than in patients with a single lesion in terms of both color fading (P<0.001) and size reduction (P<0.001). In male patients (42.2±3.9), the change in a-values, indicating coloration, was higher than in female patients (19.8 ±13.8)(P<0.001). In patients who started treatment before 6 months after birth, the size reduction was greater than in their counterparts (62.3%; range, 3.0%–93.0% vs. 15.8%; range, 1.0%–79.0%; P<0.001). Conclusions Propranolol is an efficacious treatment with a good safety profile. In patients with a single lesion, the response to treatment was better in terms of color fading and size reduction. Furthermore, male patients responded better to propranolol treatment in terms of color fading than female patients, and starting treatment before 6 months after birth was more advantageous for size reduction

    Deep Seawater flow Characteristics Around the Manganese Nodule Collecting Device

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    AbstractFlow field characteristics with outflow discharge from a collecting device in deep seawater while gathering manganese nodules have been analyzed by CFD. Numerical model is used for the analysis with CFD program of FLUENT. It is assumed that the collecting device is 4.5×5.4×6.7m with outflow speed = 1.75 m/s and the current speed = 0.1m/s.Overall seawater flow field characteristics are largely influenced by the outflow discharge from the collecting device and manganese nodule particle behavior. The outflow discharge effect reaches to about few times of the collecting device in back. As simulation results, flow velocity and streamline distributions are compared including turbulence kinetic energyvariation. This study will be useful for optimal design for manganese nodule collecting device system in deep sea

    Hu.4-1BB-Fc fusion protein inhibits allergic inflammation and airway hyperresponsiveness in a murine model of asthma

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    Purpose4-1BB (CD 137) is a costimulatory molecule expressed on activated T-cells. Repression by 4-1BB is thought to attenuate Th2-mediated allergic reactions. The aim of this study was to investigate the effect of 4-1BB on allergic airway inflammation in a murine asthma model.MethodsBALB/c mice were sensitized to and challenged with ovalbumin (OVA). Hu.4-1BB-Fc was administered 1 day before the first OVA sensitization or 1 day after the second OVA sensitization. Following antigen challenge, airway responsiveness to methacholine was assessed and bronchoalveolar lavage (BAL) fluid was analyzed. Total immunoglobulin (Ig) E, OVA-specific IgE, IgG1, and IgG2a levels in sera were measured by enzyme-linked immunosorbent assay. Lung pathology was also evaluated.ResultsIn mice treated with Hu.4-1BB-Fc before the first OVA sensitization, there was a marked decrease in airway hyperresponsiveness, total cell count, and eosinophil count in the BAL fluid. In addition, Hu.4-1BB-Fc treatment decreased serum OVA-specific IgG1 levels and increased serum IgG2a level significantly compared with the corresponding levels in mice sensitized to and challenged with OVA. Hu.4-1BB-Fc-treated mice also showed suppressed peribronchial and perivascular inflammatory cell infiltration. In contrast, treatment with Hu.4-1BB-Fc 1 day after sensitization had no effect on airway hyperresponsiveness and showed less suppression of inflammation in lung tissue.ConclusionAdministration of Hu.4-1BB-Fc can attenuate airway inflammation and hyperreactivity in a mouse model of allergic airway inflammation. In addition, administration before sensitization may be more effective. These findings suggest that 4-1BB may be a useful therapeutic molecule against asthma

    Serum high mobility group box-1 (HMGB1) is closely associated with the clinical and pathologic features of gastric cancer

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    <p>Abstract</p> <p>Background</p> <p>High mobility group box-1 (HMGB1) is a newly recognized factor regulating cancer cell tumorigenesis, expansion and invasion. We investigated the correlation between the serum HMGB1 levels and the clinical and pathologic features of gastric cancer and evaluated the validity of HMGB1 as a potential biomarker for the early diagnosis of gastric cancer.</p> <p>Methods</p> <p>A total of 227 subjects were classified into 5 disease groups according to the 'gastritis-dysplasia-carcinoma' sequence of gastric carcinogenesis and their serum levels of HMGB1 were analyzed by an enzyme-linked immunosorbent assay (ELISA) method. Clinical parameters, International Union Against Cancer (UICC) TNM stage, cancer size, differentiation or lymphatic invasion, vascular or perineural invasion and prognosis were used as analysis variables.</p> <p>Results</p> <p>The serum HMGB1 levels were significantly different among disease groups (ANOVA, <it>p < 0.05</it>) and HMGB1 levels tended to increase according to the progression of gastric carcinogenesis. Serum HMGB1 levels were significantly associated with depth of invasion, lymph node metastasis, tumor size, and poor prognosis (<it>p < 0.05</it>). However, HMGB1 levels were not associated with patient gender or age, differentiation of tumor cells, or lymphatic, vascular and perineural invasion, or the existence of distant metastasis in advanced cancer (<it>p > 0.05</it>). The sensitivity and specificity of serum HMGB1 was 71% and 67% (cut-off value of 5 ng/ml) for the diagnosis of early gastric cancer, and 70% and 64% (cut-off value of 4 ng/ml) for the diagnosis of high-risk lesions, respectively. These values were greater than those for carcinoembryonic antigen (CEA) (30–40% of sensitivity).</p> <p>Conclusion</p> <p>HMGB1 appears to be a useful serological biomarker for early diagnosis as well as evaluating the tumorigenesis, stage, and prognosis of gastric cancer.</p

    Dehydrogenation of ammonia-borane by cationic Pd(II) and Ni(II) complexes in a nitromethane medium: hydrogen release and spent fuel characterization

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    A highly electrophilic cationic PdII complex, [Pd(MeCN)_4][BF_4]_2 (1), brings about the preferential activation of the B–H bond in ammonia-borane (NH3·BH3, AB). At room temperature, the reaction between 1 in CH_3NO_2 and AB in tetraglyme leads to Pd nanoparticles and formation of spent fuels of the general formula MeNH_xBO_y as reaction byproducts, while 2 equiv. of H_2 is efficiently released per AB equiv. at room temperature within 60 seconds. For a mechanistic understanding of dehydrogenation by 1, the chemical structures of spent fuels were intensely characterized by a series of analyses such as elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), solid state magic-angle-spinning (MAS) NMR spectra (^2H, ^(13)C, ^(15)N, and ^(11)B), and cross polarization (CP) MAS methods. During AB dehydrogenation, the involvement of MeNO2 in the spent fuels showed that the mechanism of dehydrogenation catalyzed by 1 is different from that found in the previously reported results. This AB dehydrogenation derived from MeNO_2 is supported by a subsequent digestion experiment of the AB spent fuel: B(OMe)_3 and N-methylhydroxylamine ([Me(OH)N]_2CH_2), which are formed by the methanolysis of the AB spent fuel (MeNH_xBO_y), were identified by means of ^(11)B NMR and single crystal structural analysis, respectively. A similar catalytic behavior was also observed in the AB dehydrogenation catalyzed by a nickel catalyst, [Ni(MeCN)_6][BF_4]_2 (2)
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