64 research outputs found

    Contribution of hematopoietic stem cells in blood vessel formation

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    Vascular development consists of vasculogenesis and angiogenesis. The system of TIE2-Angiopoietin (Ang) is involved in angiogenesis. TIE2 regulates adhesion and dissociation between endothelial cells and mural cells, and survival, apoptosis, and chemotaxis of endothelial cells. Ang-2, which is produced by endothelial cells under tissue hypoxia, has been suggested to be a key regulator for the initiation of endothelial cell sprouting from pre-existing vessels. Although Ang-2 binds to TIE2, it does not promote activation of TIE2 on endothelial cells. Ang-2 produced from endothelial cells under hypoxia inhibits the binding of Ang-1 to TIE2. On the other hand, Ang-1 promotes activation of TIE2 and adhesion between endothelial cells and mural cells. Therefore, endothelial cells dissociated from mural cells by Ang-2 are free to move to avascular area where oxygen or nutrient is needed. We recently found that hematopoietic stem cells produce Ang-1 and promote chemotaxis and network formation of TIE2-positive endothelial cells. Moreover, hematopoietic stem cells change their fate into mural cell and stabilize the vessel structure. This novel function may be applied clinically to promote neovascularization by transplanting the hematopoietic stem cells at the desired site.Biomedical Reviews 2003; 14: 1-8

    Transformation of LEV-type zeolite into less dense CHA-type zeolite

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    Hydrothermal conversion of LEV-type zeolite into CHA-type zeolite occurred in the absence of both an organic structure-directing agent and a seed crystal. The LEV-CHA transformation proceeds from a more dense zeolite (LEV) to a less dense one (CHA). When amorphous aluminosilicate hydrogels were used as starting materials, the CHA-type zeolite was not obtained under the present hydrothermal synthesis conditions. From the fact that the LEV-CHA transformation proceeded at lower alkalinity conditions, it was suggested that locally ordered aluminosilicate species (nanoparts) produced by decomposition/dissolution of the starting LEV-type zeolite contribute to the transformation process. On the other hand, at higher alkalinity than that used for the CHA-type zeolite synthesis, LEV-LTA transformation occurred effectively and selectively. These results suggest that there is a large difference in the structures of nanoparts generated by decomposition/dissolution of the starting zeolite in the LEV-CHA and LEV-LTA transformations

    Synthesis of high-silica CHA type zeolite by interzeolite conversion of FAU type zeolite in the presence of seed crystals

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    The influence of seed crystals on the interzeolite conversion of FAU type zeolite into CHA type zeolite was investigated in the presence of benzyltrimethylammonium hydroxide as a structure-directing agent under various hydrothermal synthesis conditions. Pure and highly crystalline CHA type zeolites with a wide range of Si/Al ratios were obtained in a shorter crystallization time as compared with those obtained without seed crystals. Furthermore, we achieved the first successful synthesis of high-silica CHA type zeolite in the absence of Na(+) cations by increasing the seed content. The protonated CHA type zeolite with a Si/Al ratio of ca. 15 yielded the highest propylene yield of ca. 48 C-% in ethanol conversion into light olefins

    Removal of accidentally ingested large foreign object via the anus after watchful waiting

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    One of the commonest complaints, for which a patient arrives in hospitals, is the presence of foreign body. It could be due to accidental ingestion or any other cause which leads to presences of a foreign body in the gastrointestinal tract. It is believed that foreign objects larger than 5–6 cm in size are unlikely to pass through the duodenum. Here, we describe a case wherein the patient accidentally swallowed a 7-cm-sized mouthguard that could not be removed by emergency upper gastrointestinal endoscopy but was subsequently removed via the anus after a period of watchful waiting

    Cultivated Grapevines Represent a Symptomless Reservoir for the Transmission of Hop Stunt Viroid to Hop Crops: 15 Years of Evolutionary Analysis

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    Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics

    Optimal labeling condition of antibodies available for immunofluorescence endoscopy

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    Purpose: In recent years, labeled antibodies have been used for diagnostic imaging in many studies. In this study, we investigated the mode of binding in antibodies labeled with ICG derivatives newly developed for the diagnosis of microcarcinomas, and evaluated the optimal binding molar ratio between the labeling compounds and antibody. Methods: MUC1 antibody and ICG derivatives (ICG-ATT and ICG-sulfo-OSu) were used. ICG derivatives noncovalently bound to the antibody were removed with ethyl acetate, and the ratio of ICG derivatives covalently bound to the labeled antibody was confirmed. During purification of the labeled antibody, the amount of each labeling compound reacting with 1molecule of the antibody varied as follows: 4, 8, 16, and 32molar equivalents. Subsequently, the intensity of fluorescence was evaluated by spectroscopy and infrared fluoroscopy. Results : The ratio of residual ICG derivative labeling the antibody was 67.4% for ICG-ATT and 65.0% for ICG-sulfo-OSu. When fluorescent antibody labeled with ICG-ATT at anF/Pratio of 2.94or 4.18wasused, specific and clear fluorescent images of the antigen were obtained. When ICG-ATT-labeled antibody at an F/P ratio of 6.50 or 6.75 was used, the fluorescence intensity decreased and the fluorescent images of antigen became unclear. Conclusions: It was found that the ICG-ATT-labeled antibody was a more specific and sensitive marker than ICG-sulfo-OSu-labeled antibody, and that lower binding molar ratios of ICG-ATT were more useful for labeling the antibody

    2006ネン ニ トクシマシ シロヤマ ニ ショクジュ サレタ ホルトノキ ノ ナエギ ノ ゲンジョウ : セイイク ジョウキョウ ト ホルトノキ イオウビョウ カンセン ジョウキョウ ニツイテ

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    Elaeocarpus zollingeri (synonym: E. sylvestris) was one of dominant trees in Mt. Shiroyama in the Tokushima City until 1970s, however, most of adult trees have died by Elaeocarpus yellows. To prevent extinction 300 nursery trees were planted at the foot of the mountain by local volunteers in 2006. In this study we investigated their survival, growth, and infection status of the disease. We found 40 nursery trees have survived (survival rate was 13%). Survived trees were abundant in areas facing the south, and most trees disappeared in areas facing the north and the west. Growth of the trees was well also in areas facing the south. Among the survived 40 nursery trees, we found three trees infected with phytoplasma, the pathogen of Elaeocarpus yellows, based on PCR analysis. It is not clear when they were infected with phytoplasma, whether they have infected after the plantation or they already had phytoplasma in the seed. Anyway, the fact that only a few tree is infected must be gratifying in considering the conservation E. zollinger in Mt. Shiroyama

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    ゼオライト合成におけるゼオライト転換法の可能性

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