The Experts below are selected from a list of 133188 Experts worldwide ranked by ideXlab platform
L S Cederbaum - One of the best experts on this subject based on the ideXlab platform.
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molecular double core hole electron spectroscopy for chemical analysis
Journal of Chemical Physics, 2010Co-Authors: Motomichi Tashiro, Masahiro Ehara, H Fukuzawa, K Ueda, Christian Buth, Nikolai V Kryzhevoi, L S CederbaumAbstract:We explore the potential of double core hole electron spectroscopy for chemical analysis in terms of x-ray two-photon photoelectron spectroscopy. The creation of deep single and double core vacancies induces significant reorganization of valence electrons. The corresponding relaxation energies and the interatomic relaxation energies are evaluated by complete active space self-consistent field (CASSCF) calculations. We propose a method on how to experimentally extract these quantities by the measurement of single ionization potentials (Ips) and double core hole ionization potentials (DIps). The influence of the chemical environment on these DIps is also discussed for states with two holes at the same atomic site and states with two holes at two different atomic sites. Electron density difference between the ground and double core hole states clearly shows the relaxations accompanying the double core hole ionization. The effect is also compared to the sensitivity of single core hole Ips arising in single co...
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molecular double core hole electron spectroscopy for chemical analysis
arXiv: Chemical Physics, 2010Co-Authors: Motomichi Tashiro, Masahiro Ehara, H Fukuzawa, K Ueda, Christian Buth, Nikolai V Kryzhevoi, L S CederbaumAbstract:We explore the potential of double core hole electron spectroscopy for chemical analysis in terms of x-ray two-photon photoelectron spectroscopy (XTPPS). The creation of deep single and double core vacancies induces significant reorganization of valence electrons. The corresponding relaxation energies and the interatomic relaxation energies are evaluated by CASSCF calculations. We propose a method how to experimentally extract these quantities by the measurement of single and double core-hole ionization potentials (Ips and DIps). The influence of the chemical environment on these DIps is also discussed for states with two holes at the same atomic site and states with two holes at two different atomic sites. Electron density difference between the ground and double core-hole states clearly shows the relaxations accompanying the double core-hole ionization. The effect is also compared with the sensitivity of single core hole ionization potentials (Ips) arising in single core hole electron spectroscopy. We have demonstrated the method for a representative set of small molecules LiF, BeO, BF, CO, N2, C2H2, C2H4, C2H6, CO2 and N2O. The scalar relativistic effect on Ips and on DIps are briefly addressed.
John F. Tisdale - One of the best experts on this subject based on the ideXlab platform.
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efficient generation of β globin expressing erythroid cells using stromal cell derived induced pluripotent stem cells from patients with sickle cell disease
Stem Cells, 2017Co-Authors: Naoya Uchida, Atsushi Fujita, Thomas Winkler, Juan J Haromora, Duckyeon Lee, Matthew M Hsieh, John F. TisdaleAbstract:Human embryonic stem (ES) cells and induced pluripotent stem (Ips) cells represent an ideal source for in vitro modeling of erythropoiesis and a potential alternative source for red blood cell transfusions. However, Ips cell-derived erythroid cells predominantly produce e- and γ-globin without β-globin production. We recently demonstrated that ES cell-derived sacs (ES sacs), known to express hemangioblast markers, allow for efficient erythroid cell generation with β-globin production. In this study, we generated several Ips cell lines derived from bone marrow stromal cells (MSCs) and peripheral blood erythroid progenitors (EPs) from sickle cell disease patients, and evaluated hematopoietic stem/progenitor cell (HSPC) generation after Ips sac induction as well as subsequent erythroid differentiation. MSC-derived Ips sacs yielded greater amounts of immature hematopoietic progenitors (VEGFR2 + GPA−), definitive HSPCs (CD34 + CD45+), and megakaryoerythroid progenitors (GPA + CD41a+), as compared to EP-derived Ips sacs. Erythroid differentiation from MSC-derived Ips sacs resulted in greater amounts of erythroid cells (GPA+) and higher β-globin (and βS-globin) expression, comparable to ES sac-derived cells. These data demonstrate that human MSC-derived Ips sacs allow for more efficient erythroid cell generation with higher β-globin production, likely due to heightened emergence of immature progenitors. Our findings should be important for Ips cell-derived erythroid cell generation. Stem Cells 2017;35:586–596
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more efficient generation of β globin expressing erythroid cells using stromal cell derived induced pluripotent stem cells
Blood, 2015Co-Authors: Naoya Uchida, Thomas Winkler, Fujita Atsushi, Haromora J Juan, John F. TisdaleAbstract:Human embryonic stem (ES) cells and induced pluripotent stem (Ips) cells represent a potential alternative source for red blood cell transfusion. Using traditional embryoid body methods, Ips cell-derived erythroid cells predominantly produce e-globin and γ-globin without β-globin expression. We recently demonstrated that ES cell-derived sacs (ES sacs), known to express hemangioblast markers, allow for efficient erythroid cell generation with β-globin production, which is associated with emergence of CD34+ hematopoietic stem/progenitor cells (HSPCs) (2014 ASH). In the current study, we extend this work to evaluate erythroid cell generation using Ips cell lines generated from various sources including patients with sickle cell disease (SCD). To test our two hypotheses; (1) erythroid progenitor (EP)-derived Ips cells more efficiently differentiate to erythroid cells, and (2) stromal cell (ST)-derived Ips cells more efficiently emerge hemangioblast-like immature HSPCs which results in greater erythroid cell generation, we generated several clones of Ips cells which were derived from (1) EPs (6 clones) which were differentiated from peripheral blood mononuclear cells and (2) bone marrow STs (5 clones) in SCD patients. Transgene-free Ips cells were generated and characterized according to Merling et al. (Blood. 2013). These Ips cells and controls (2 clones of fibroblast (FB)-derived Ips cells and H1 ES cells) were used to generate ES/Ips sacs for 15 days. After a 2 day culture of ES/Ips sac-derived spherical cells on OP9 feeder cells, the suspension cells were differentiated into erythroid cells using human erythroid massive amplification culture for 13 days (Blood cells Mol Dis. 2002). Following ES/Ips sac generation, 3.5-4.8 fold greater amounts of CD34+CD45+ HSPCs emerged in both EP- and ST-derived Ips sacs, compared to FB-derived Ips sacs (p<0.01). After an additional 2 weeks of erythroid differentiation, we observed 4.5-8.7 fold greater amounts of GPA+ erythroid cells from both EP- and SC-derived Ips sacs, compared to FB-derived Ips sacs (p<0.01). Interestingly, ST-derived Ips sacs resulted in 1.4-2.0 fold greater amounts of CD34+CD45+ HSPCs and GPA+ erythroid cells (p<0.01), compared to EP-derived Ips sacs. Higher β-globin expression (21.5±4.3%) was observed by RT-qPCR in erythroid cells from ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (4.4±2.5% and 8.3±4.2%, respectively, p<0.01), which was comparable to ES sacs (23.3%). Sickle hemoglobin was detected by hemoglobin electrophoresis. The ES/Ips sac-derived erythroid cell generation was more strongly affected by cell sources (5-6 fold larger SD) than variations among Ips cell clones. These data demonstrate that ST-derived Ips sacs allow more efficient erythroid cell generation with higher β-globin production, compared to EP- and FB-derived Ips sacs. We hypothesized that ST-derived Ips sacs contain greater amounts of immature HSPCs (including hemogenic endothelium) and immature EPs (including megakaryoerythroid progenitors), since more expansion of ST-derived cells was observed during the late phase of erythroid differentiation, compared to EP- and FB-derived cells. We evaluated hemogenic endothelium markers at day 15, and observed 7.7 fold greater amounts of VEGFR+GPA- cells (p<0.01) and 1.3-1.4 fold greater amounts of CD31+CD34+ cells in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (not detectable VEGFR+GPA- cells in EP-derived Ips sacs). Before erythroid differentiation, 3.2-16.4 fold greater amounts of GPA+CD41a+ megakaryoerythroid progenitors were observed in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (p<0.05). In colony forming unit assays, 1.8-5.0 fold greater amounts of myeloid and erythroid colonies were observed in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (p<0.01). These data suggest that ST-derived Ips sacs more efficiently produce immature HSPCs and immature EPs, which may result in more efficient generation of erythroid cells with β-globin production. In summary, we demonstrated that human ST-derived Ips sacs allow for more efficient erythroid cell generation with higher β-globin production, which could be caused by heightened emergence of hemogenic endothelium in ST-derived Ips sacs. Our findings should be important for in in vitro Ips cell-derived erythroid cell generation with high β-globin expression. Disclosures Winkler: Novartis: Research Funding; GSK: Research Funding.
Motomichi Tashiro - One of the best experts on this subject based on the ideXlab platform.
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molecular double core hole electron spectroscopy for chemical analysis
Journal of Chemical Physics, 2010Co-Authors: Motomichi Tashiro, Masahiro Ehara, H Fukuzawa, K Ueda, Christian Buth, Nikolai V Kryzhevoi, L S CederbaumAbstract:We explore the potential of double core hole electron spectroscopy for chemical analysis in terms of x-ray two-photon photoelectron spectroscopy. The creation of deep single and double core vacancies induces significant reorganization of valence electrons. The corresponding relaxation energies and the interatomic relaxation energies are evaluated by complete active space self-consistent field (CASSCF) calculations. We propose a method on how to experimentally extract these quantities by the measurement of single ionization potentials (Ips) and double core hole ionization potentials (DIps). The influence of the chemical environment on these DIps is also discussed for states with two holes at the same atomic site and states with two holes at two different atomic sites. Electron density difference between the ground and double core hole states clearly shows the relaxations accompanying the double core hole ionization. The effect is also compared to the sensitivity of single core hole Ips arising in single co...
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molecular double core hole electron spectroscopy for chemical analysis
arXiv: Chemical Physics, 2010Co-Authors: Motomichi Tashiro, Masahiro Ehara, H Fukuzawa, K Ueda, Christian Buth, Nikolai V Kryzhevoi, L S CederbaumAbstract:We explore the potential of double core hole electron spectroscopy for chemical analysis in terms of x-ray two-photon photoelectron spectroscopy (XTPPS). The creation of deep single and double core vacancies induces significant reorganization of valence electrons. The corresponding relaxation energies and the interatomic relaxation energies are evaluated by CASSCF calculations. We propose a method how to experimentally extract these quantities by the measurement of single and double core-hole ionization potentials (Ips and DIps). The influence of the chemical environment on these DIps is also discussed for states with two holes at the same atomic site and states with two holes at two different atomic sites. Electron density difference between the ground and double core-hole states clearly shows the relaxations accompanying the double core-hole ionization. The effect is also compared with the sensitivity of single core hole ionization potentials (Ips) arising in single core hole electron spectroscopy. We have demonstrated the method for a representative set of small molecules LiF, BeO, BF, CO, N2, C2H2, C2H4, C2H6, CO2 and N2O. The scalar relativistic effect on Ips and on DIps are briefly addressed.
Anna Falk - One of the best experts on this subject based on the ideXlab platform.
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derivation of human Ips cell lines from monozygotic twins in defined and xeno free conditions
Stem Cell Research, 2017Co-Authors: Elias Uhlin, Harriet Ronnholm, Kelly Day, Malin Kele, Kristiina Tammimies, Sven Bolte, Anna FalkAbstract:Human induced pluripotent stem (hIps) cell lines CTRL-9-II and CTRL-10-I were derived from healthy monozygotic twin donors using non-integrating RNA based Sendai virus reprogramming and cultured in a xeno-free chemically defined condition. The established hIps cell lines, CTRL-9-II and CTRL-10-I, are karyotypically normal, free from reprogramming vectors, display endogenously expression of pluripotency factors at levels similar to embryonic stem cells. The generated Ips cell lines demonstrate pluripotency by passing bioinformatics assay PluriTest and by embryonic body assay.
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treatment of a mouse model of spinal cord injury by transplantation of human induced pluripotent stem cell derived long term self renewing neuroepithelial like stem cells
Stem Cells, 2012Co-Authors: Yusuke Fujimoto, Anna Falk, Masahiko Abematsu, Keita Tsujimura, Tsukasa Sanosaka, Berry Juliandi, Katsunori Semi, Masakazu Namihira, Setsuro KomiyaAbstract:Because of their ability to self-renew, to differentiate into multiple lineages, and to migrate toward a damaged site, neural stem cells (NSCs), which can be derived from various sources such as fetal tissues and embryonic stem cells, are currently considered to be promising components of cell replacement strategies aimed at treating injuries of the central nervous system, including the spinal cord. Despite their efficiency in promoting functional recovery, these NSCs are not homogeneous and possess variable characteristics depending on their derivation protocols. The advent of induced pluripotent stem (Ips) cells has provided new prospects for regenerative medicine. We used a recently developed robust and stable protocol for the generation of long-term, self-renewing, neuroepithelial-like stem cells from human Ips cells (hIps-lt-NES cells), which can provide a homogeneous and well-defined population of NSCs for standardized analysis. Here, we show that transplanted hIps-lt-NES cells differentiate into neural lineages in the mouse model of spinal cord injury (SCI) and promote functional recovery of hind limb motor function. Furthermore, using two different neuronal tracers and ablation of the transplanted cells, we revealed that transplanted hIps-lt-NES cell-derived neurons, together with the surviving endogenous neurons, contributed to restored motor function. Both types of neurons reconstructed the corticospinal tract by forming synaptic connections and integrating neuronal circuits. Our findings indicate that hIps-lt-NES transplantation represents a promising avenue for effective cell-based treatment of SCI.
Naoya Uchida - One of the best experts on this subject based on the ideXlab platform.
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efficient generation of β globin expressing erythroid cells using stromal cell derived induced pluripotent stem cells from patients with sickle cell disease
Stem Cells, 2017Co-Authors: Naoya Uchida, Atsushi Fujita, Thomas Winkler, Juan J Haromora, Duckyeon Lee, Matthew M Hsieh, John F. TisdaleAbstract:Human embryonic stem (ES) cells and induced pluripotent stem (Ips) cells represent an ideal source for in vitro modeling of erythropoiesis and a potential alternative source for red blood cell transfusions. However, Ips cell-derived erythroid cells predominantly produce e- and γ-globin without β-globin production. We recently demonstrated that ES cell-derived sacs (ES sacs), known to express hemangioblast markers, allow for efficient erythroid cell generation with β-globin production. In this study, we generated several Ips cell lines derived from bone marrow stromal cells (MSCs) and peripheral blood erythroid progenitors (EPs) from sickle cell disease patients, and evaluated hematopoietic stem/progenitor cell (HSPC) generation after Ips sac induction as well as subsequent erythroid differentiation. MSC-derived Ips sacs yielded greater amounts of immature hematopoietic progenitors (VEGFR2 + GPA−), definitive HSPCs (CD34 + CD45+), and megakaryoerythroid progenitors (GPA + CD41a+), as compared to EP-derived Ips sacs. Erythroid differentiation from MSC-derived Ips sacs resulted in greater amounts of erythroid cells (GPA+) and higher β-globin (and βS-globin) expression, comparable to ES sac-derived cells. These data demonstrate that human MSC-derived Ips sacs allow for more efficient erythroid cell generation with higher β-globin production, likely due to heightened emergence of immature progenitors. Our findings should be important for Ips cell-derived erythroid cell generation. Stem Cells 2017;35:586–596
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more efficient generation of β globin expressing erythroid cells using stromal cell derived induced pluripotent stem cells
Blood, 2015Co-Authors: Naoya Uchida, Thomas Winkler, Fujita Atsushi, Haromora J Juan, John F. TisdaleAbstract:Human embryonic stem (ES) cells and induced pluripotent stem (Ips) cells represent a potential alternative source for red blood cell transfusion. Using traditional embryoid body methods, Ips cell-derived erythroid cells predominantly produce e-globin and γ-globin without β-globin expression. We recently demonstrated that ES cell-derived sacs (ES sacs), known to express hemangioblast markers, allow for efficient erythroid cell generation with β-globin production, which is associated with emergence of CD34+ hematopoietic stem/progenitor cells (HSPCs) (2014 ASH). In the current study, we extend this work to evaluate erythroid cell generation using Ips cell lines generated from various sources including patients with sickle cell disease (SCD). To test our two hypotheses; (1) erythroid progenitor (EP)-derived Ips cells more efficiently differentiate to erythroid cells, and (2) stromal cell (ST)-derived Ips cells more efficiently emerge hemangioblast-like immature HSPCs which results in greater erythroid cell generation, we generated several clones of Ips cells which were derived from (1) EPs (6 clones) which were differentiated from peripheral blood mononuclear cells and (2) bone marrow STs (5 clones) in SCD patients. Transgene-free Ips cells were generated and characterized according to Merling et al. (Blood. 2013). These Ips cells and controls (2 clones of fibroblast (FB)-derived Ips cells and H1 ES cells) were used to generate ES/Ips sacs for 15 days. After a 2 day culture of ES/Ips sac-derived spherical cells on OP9 feeder cells, the suspension cells were differentiated into erythroid cells using human erythroid massive amplification culture for 13 days (Blood cells Mol Dis. 2002). Following ES/Ips sac generation, 3.5-4.8 fold greater amounts of CD34+CD45+ HSPCs emerged in both EP- and ST-derived Ips sacs, compared to FB-derived Ips sacs (p<0.01). After an additional 2 weeks of erythroid differentiation, we observed 4.5-8.7 fold greater amounts of GPA+ erythroid cells from both EP- and SC-derived Ips sacs, compared to FB-derived Ips sacs (p<0.01). Interestingly, ST-derived Ips sacs resulted in 1.4-2.0 fold greater amounts of CD34+CD45+ HSPCs and GPA+ erythroid cells (p<0.01), compared to EP-derived Ips sacs. Higher β-globin expression (21.5±4.3%) was observed by RT-qPCR in erythroid cells from ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (4.4±2.5% and 8.3±4.2%, respectively, p<0.01), which was comparable to ES sacs (23.3%). Sickle hemoglobin was detected by hemoglobin electrophoresis. The ES/Ips sac-derived erythroid cell generation was more strongly affected by cell sources (5-6 fold larger SD) than variations among Ips cell clones. These data demonstrate that ST-derived Ips sacs allow more efficient erythroid cell generation with higher β-globin production, compared to EP- and FB-derived Ips sacs. We hypothesized that ST-derived Ips sacs contain greater amounts of immature HSPCs (including hemogenic endothelium) and immature EPs (including megakaryoerythroid progenitors), since more expansion of ST-derived cells was observed during the late phase of erythroid differentiation, compared to EP- and FB-derived cells. We evaluated hemogenic endothelium markers at day 15, and observed 7.7 fold greater amounts of VEGFR+GPA- cells (p<0.01) and 1.3-1.4 fold greater amounts of CD31+CD34+ cells in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (not detectable VEGFR+GPA- cells in EP-derived Ips sacs). Before erythroid differentiation, 3.2-16.4 fold greater amounts of GPA+CD41a+ megakaryoerythroid progenitors were observed in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (p<0.05). In colony forming unit assays, 1.8-5.0 fold greater amounts of myeloid and erythroid colonies were observed in ST-derived Ips sacs, compared to EP- and FB-derived Ips sacs (p<0.01). These data suggest that ST-derived Ips sacs more efficiently produce immature HSPCs and immature EPs, which may result in more efficient generation of erythroid cells with β-globin production. In summary, we demonstrated that human ST-derived Ips sacs allow for more efficient erythroid cell generation with higher β-globin production, which could be caused by heightened emergence of hemogenic endothelium in ST-derived Ips sacs. Our findings should be important for in in vitro Ips cell-derived erythroid cell generation with high β-globin expression. Disclosures Winkler: Novartis: Research Funding; GSK: Research Funding.
