The Experts below are selected from a list of 54348 Experts worldwide ranked by ideXlab platform
Linda L. Demer - One of the best experts on this subject based on the ideXlab platform.
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Vitamin D and osteogenic differentiation in the Artery Wall.
Clinical journal of the American Society of Nephrology : CJASN, 2008Co-Authors: Jeffrey J. Hsu, Yin Tintut, Linda L. DemerAbstract:Vascular calcification is widespread, particularly in patients with chronic kidney disease, who receive, among other treatments, active vitamin D supplements. Emerging evidence indicates that vascular calcification is a regulated process that resembles embryonic endochondral osteogenesis, involving osteoblastic differentiation of vascular smooth muscle cells. In experimental animal models, high dosages of vitamin D consistently promote vascular calcification. In particular, the vitamin D–fed rat is frequently used as a model to assess putative regulators of calcific vasculopathy. The Artery Wall calcification in these animals most likely results from multiple mechanisms involving systems physiology of the complex, bone-vascular-renal-endocrine axis. Genetically engineered mice with upregulated vitamin D signaling pathways have also shed light on the molecular intermediaries, including fibroblast growth factor-23 and transcriptional intermediary factor 1-α. In contrast to the studies of animals, studies of humans show that vitamin D has an inverse relationship or little effect. This difference between in vitro and in vivo findings is most likely, again, due to the complex, systemic feedback regulatory mechanisms that control calcium-phosphate metabolism. Recent epidemiologic evidence suggests that there is a narrow range of vitamin D levels in which vascular function is optimized. Levels above or below this range seem to confer a significant increase in risk for cardiovascular disease. There is some evidence to suggest that dietary vitamin D may be carried by lipoprotein particles into cells of the Artery Wall and atherosclerotic plaque, where it may be converted to active form by monocyte-macrophages. These findings raise interesting questions regarding the effects of vitamin D intake on atherosclerotic calcification and cardiovascular risk.
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Return to Ectopia Stem Cells in the Artery Wall
Arteriosclerosis thrombosis and vascular biology, 2005Co-Authors: Linda L. Demer, Yin TintutAbstract:In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Rattazzi and colleagues demonstrate definitively that true cartilage and calcified cartilage tissue develop in the Artery Wall of the apoE (−/−) mouse.1 This key observation of neocartilage in a hyperlipidemic mouse provides strong support for the existence and function of vascular stem cells, and raises important questions about the origin of cells that produce ectopic tissue and the regulatory mechanisms determining their lineage identity. See page 1420 The origin of ectopic vascular tissue remains unknown. Some possibilities include transdifferentiation of mature smooth muscle cells, initial differentiation of immature cells, and/or dedifferentiation of mature cells followed by redifferentiation. It is not known whether the cells arise from the Artery Wall, perhaps as embryonic remnants, or migrate from the circulation, after release from another tissue, such as the marrow stroma. The spectrum of lineages represented in vascular ectopic tissue is similar to that of marrow stromal cells and mesenchymal stem cells, suggesting that ectopic tissue is a manifestation of adult mesenchymal stem cells. In the past year, 3 groups independently demonstrated multilineage potential in adult vascular cells in vitro and in vivo, including chondrogenic, osteogenic, leiomyogenic, and, in some cases, adipogenic lineages.2–4 …
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Mesenchymal stem cells and the Artery Wall.
Circulation research, 2004Co-Authors: Moeen Abedin, Yin Tintut, Linda L. DemerAbstract:The presence of ectopic tissue in the diseased Artery Wall is evidence for the presence of multipotential stem cells in the vasculature. Mesenchymal stem cells were first identified in the marrow stroma, and they differentiate along multiple lineages giving rise to cartilage, bone, fat, muscle, and vascular tissue in vitro and in vivo. Transplantation studies show that marrow-derived mesenchymal stem cells appear to enter the circulation and engraft other tissues, including the Artery Wall, at sites of injury. Recent evidence indicates that mesenchymal stem cells are also present in normal Artery Wall and microvessels and that they also may enter the circulation, contributing to the population of circulating progenitor cells and engrafting other tissues. Thus, the Artery Wall is not only a destination but also a source of progenitor cells that have regenerative potential. Although potential artifacts, such as fusion, need to be taken into consideration, these new developments in vascular biology open important therapeutic avenues. A greater understanding of how mesenchymal stem cells from the bone marrow or Artery Wall bring about vascular regeneration and repair may lead to novel cell-based treatments for cardiovascular disease.
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Homeostasis of Lipid Oxidation in the Artery Wall
Cardiovascular Disease 2, 1995Co-Authors: Alan M. Fogelman, Linda L. Demer, Judith A. Berliner, M Navab, Ali Andalibi, Mary C. Territo, Feng Liao, Aldons J. LusisAbstract:The subendothelial space is a complex network of collagen fibers and connecting fibrils.1 Within two hours of injecting low density lipoprotein (LDL) into the femoral vein of a rabbit, the LDL was found trapped in the three dimensional matrix network.2 The trapped LDL appeared to bind to the collagen fibers near the junction of connecting fibrils.3 The bound LDL was no longer in solution and appeared to be trapped in a microenvironment that excluded water soluble antioxidants such as vitamin C.4 The LDL lipids were then exposed to oxidative products released by the surrounding Artery Wall cells and oxidation of a mild degree occurred such that the resulting LDL was so minimally modified that it’s bouyant density, Rf, and receptor recognition were not different from native LDL.5 However, this mildly oxidized LDL, when applied to endothelial cells in culture induced the endothelial cells to bind monocytes but not neutrophils and to produce a chemotactic factor that induced monocyte migration.5 All of the biologic activity in this mildly oxidized LDL was contained in the polar lipids.5 The mildly oxidized LDL induced endothelial cells to express the gene and protein for the potent macrophage differentiation factor M-CSF.6 The mildly oxidized LDL also induced endothelial cells and smooth muscle cells to express the gene and protein for the potent monocyte chemoattractant - monocyte chemotactic protein-1 (MCP-1).7 Injection of the mildly oxidized LDL into mice produced an increase in blood M-CSF and expression of JE, the mouse homologue of the MCP-1 gene.8 LDL given to co-cultures of human Artery Wall cells was sequestered in a microenvironment protected from aqueous antioxidants and, when recovered from the co-cultures, induced fresh co-cultures to express the gene and protein for MCP-1.
Han Wen - One of the best experts on this subject based on the ideXlab platform.
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coronary Artery Wall imaging in mice using osmium tetroxide and micro computed tomography micro ct
Journal of Anatomy, 2012Co-Authors: Vinay M Pai, Megan Kozlowski, Danielle Donahue, Elishiah Miller, Xianghui Xiao, Marcus Y Chen, Patricia S Connelly, Kenneth R Jeffries, Han WenAbstract:The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary Artery disease models, it is highly desirable to image coronary Artery Walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO(4) ) solution. As a tissue-staining contrast agent, OsO(4) is retained in the vessel Wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the Artery Wall visible in CT. Additionally, since OsO(4) preferentially binds to lipids, it highlights lipid deposition in the Artery Wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE(-/-) ) mice at 10 μm resolution. The results show that Walls of coronary arteries as small as 45 μm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO(4) and micro-CT permits the visualization of the coronary Artery Wall in intact mouse hearts.
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Coronary Artery Wall imaging in mice using osmium tetroxide and micro‐computed tomography (micro‐CT)
Journal of anatomy, 2012Co-Authors: Vinay M Pai, Megan Kozlowski, Danielle Donahue, Elishiah Miller, Xianghui Xiao, Marcus Y Chen, Patricia S Connelly, Kenneth R Jeffries, Han WenAbstract:The high spatial resolution of micro-computed tomography (micro-CT) is ideal for 3D imaging of coronary arteries in intact mouse heart specimens. Previously, micro-CT of mouse heart specimens utilized intravascular contrast agents that hardened within the vessel lumen and allowed a vascular cast to be made. However, for mouse coronary Artery disease models, it is highly desirable to image coronary Artery Walls and highlight plaques. For this purpose, we describe an ex vivo contrast-enhanced micro-CT imaging technique based on tissue staining with osmium tetroxide (OsO(4) ) solution. As a tissue-staining contrast agent, OsO(4) is retained in the vessel Wall and surrounding tissue during the fixation process and cleared from the vessel lumens. Its high X-ray attenuation makes the Artery Wall visible in CT. Additionally, since OsO(4) preferentially binds to lipids, it highlights lipid deposition in the Artery Wall. We performed micro-CT of heart specimens of 5- to 25-week-old C57BL/6 wild-type mice and 5- to 13-week-old apolipoprotein E knockout (apoE(-/-) ) mice at 10 μm resolution. The results show that Walls of coronary arteries as small as 45 μm in diameter are visible using a table-top micro-CT scanner. Similar image clarity was achieved with 1/2000th the scan time using a synchrotron CT scanner. In 13-week-old apoE mice, lipid-rich plaques are visible in the aorta. Our study shows that the combination of OsO(4) and micro-CT permits the visualization of the coronary Artery Wall in intact mouse hearts.
Dhanjoo Ghista - One of the best experts on this subject based on the ideXlab platform.
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robust estimation of carotid Artery Wall motion using the elasticity based state space approach
Medical Image Analysis, 2017Co-Authors: Zhifan Gao, Huahua Xiong, Xin Liu, Heye Zhang, Dhanjoo GhistaAbstract:Abstract The dynamics of the carotid Artery Wall has been recognized as a valuable indicator to evaluate the status of atherosclerotic disease in the preclinical stage. However, it is still a challenge to accurately measure this dynamics from ultrasound images. This paper aims at developing an elasticity-based state-space approach for accurately measuring the two-dimensional motion of the carotid Artery Wall from the ultrasound imaging sequences. In our approach, we have employed a linear elasticity model of the carotid Artery Wall, and converted it into the state space equation. Then, the two-dimensional motion of carotid Artery Wall is computed by solving this state-space approach using the H ∞ filter and the block matching method. In addition, a parameter training strategy is proposed in this study for dealing with the parameter initialization problem. In our experiment, we have also developed an evaluation function to measure the tracking accuracy of the motion of the carotid Artery Wall by considering the influence of the sizes of the two blocks (acquired by our approach and the manual tracing) containing the same carotid Wall tissue and their overlapping degree. Then, we have compared the performance of our approach with the manual traced results drawn by three medical physicians on 37 healthy subjects and 103 unhealthy subjects. The results have showed that our approach was highly correlated (Pearson’s correlation coefficient equals 0.9897 for the radial motion and 0.9536 for the longitudinal motion), and agreed well (width the 95% confidence interval is 89.62 µm for the radial motion and 387.26 µm for the longitudinal motion) with the manual tracing method. We also compared our approach to the three kinds of previous methods, including conventional block matching methods, Kalman-based block matching methods and the optical flow. Altogether, we have been able to successfully demonstrate the efficacy of our elasticity-model based state-space approach (EBS) for more accurate tracking of the 2-dimensional motion of the carotid Artery Wall, towards more effective assessment of the status of atherosclerotic disease in the preclinical stage.
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MICCAI (3) - Carotid Artery Wall Motion Estimated from Ultrasound Imaging Sequences Using a Nonlinear State Space Approach
Lecture Notes in Computer Science, 2016Co-Authors: Zhifan Gao, Huahua Xiong, Xin Liu, Heye Zhang, Dhanjoo Ghista, Yuanyuan Sun, Yaoqin XieAbstract:It is very challenge to investigate the motion of the carotid Artery Wall in ultrasound images, because of the high nonlinear dynamics of this motion. In our study, the nonlinear dynamics of carotid Artery Wall motion is first approximated by our nonlinear state-space approach driven by a mathematical model of the mechanical deformation of carotid Artery Wall. Then, the two-dimensional motion of carotid Artery Wall is computed by solving the nonlinear state-space approach using the unscented Kalman filter. We have then evaluated the performance of our approach by comparing it with the manual tracing method (the correlation coefficient equals 0.9897 for the radial motion and 0.9703 for the longitudinal motion) and three other state-of-the-art methods for 73 subjects. The results indicate the reliable applicability of our approach in tracking the motion of the carotid Artery Wall and its potential usefulness in routine clinical diagnosis.
Yin Tintut - One of the best experts on this subject based on the ideXlab platform.
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Vitamin D and osteogenic differentiation in the Artery Wall.
Clinical journal of the American Society of Nephrology : CJASN, 2008Co-Authors: Jeffrey J. Hsu, Yin Tintut, Linda L. DemerAbstract:Vascular calcification is widespread, particularly in patients with chronic kidney disease, who receive, among other treatments, active vitamin D supplements. Emerging evidence indicates that vascular calcification is a regulated process that resembles embryonic endochondral osteogenesis, involving osteoblastic differentiation of vascular smooth muscle cells. In experimental animal models, high dosages of vitamin D consistently promote vascular calcification. In particular, the vitamin D–fed rat is frequently used as a model to assess putative regulators of calcific vasculopathy. The Artery Wall calcification in these animals most likely results from multiple mechanisms involving systems physiology of the complex, bone-vascular-renal-endocrine axis. Genetically engineered mice with upregulated vitamin D signaling pathways have also shed light on the molecular intermediaries, including fibroblast growth factor-23 and transcriptional intermediary factor 1-α. In contrast to the studies of animals, studies of humans show that vitamin D has an inverse relationship or little effect. This difference between in vitro and in vivo findings is most likely, again, due to the complex, systemic feedback regulatory mechanisms that control calcium-phosphate metabolism. Recent epidemiologic evidence suggests that there is a narrow range of vitamin D levels in which vascular function is optimized. Levels above or below this range seem to confer a significant increase in risk for cardiovascular disease. There is some evidence to suggest that dietary vitamin D may be carried by lipoprotein particles into cells of the Artery Wall and atherosclerotic plaque, where it may be converted to active form by monocyte-macrophages. These findings raise interesting questions regarding the effects of vitamin D intake on atherosclerotic calcification and cardiovascular risk.
-
Return to Ectopia Stem Cells in the Artery Wall
Arteriosclerosis thrombosis and vascular biology, 2005Co-Authors: Linda L. Demer, Yin TintutAbstract:In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology , Rattazzi and colleagues demonstrate definitively that true cartilage and calcified cartilage tissue develop in the Artery Wall of the apoE (−/−) mouse.1 This key observation of neocartilage in a hyperlipidemic mouse provides strong support for the existence and function of vascular stem cells, and raises important questions about the origin of cells that produce ectopic tissue and the regulatory mechanisms determining their lineage identity. See page 1420 The origin of ectopic vascular tissue remains unknown. Some possibilities include transdifferentiation of mature smooth muscle cells, initial differentiation of immature cells, and/or dedifferentiation of mature cells followed by redifferentiation. It is not known whether the cells arise from the Artery Wall, perhaps as embryonic remnants, or migrate from the circulation, after release from another tissue, such as the marrow stroma. The spectrum of lineages represented in vascular ectopic tissue is similar to that of marrow stromal cells and mesenchymal stem cells, suggesting that ectopic tissue is a manifestation of adult mesenchymal stem cells. In the past year, 3 groups independently demonstrated multilineage potential in adult vascular cells in vitro and in vivo, including chondrogenic, osteogenic, leiomyogenic, and, in some cases, adipogenic lineages.2–4 …
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Mesenchymal stem cells and the Artery Wall.
Circulation research, 2004Co-Authors: Moeen Abedin, Yin Tintut, Linda L. DemerAbstract:The presence of ectopic tissue in the diseased Artery Wall is evidence for the presence of multipotential stem cells in the vasculature. Mesenchymal stem cells were first identified in the marrow stroma, and they differentiate along multiple lineages giving rise to cartilage, bone, fat, muscle, and vascular tissue in vitro and in vivo. Transplantation studies show that marrow-derived mesenchymal stem cells appear to enter the circulation and engraft other tissues, including the Artery Wall, at sites of injury. Recent evidence indicates that mesenchymal stem cells are also present in normal Artery Wall and microvessels and that they also may enter the circulation, contributing to the population of circulating progenitor cells and engrafting other tissues. Thus, the Artery Wall is not only a destination but also a source of progenitor cells that have regenerative potential. Although potential artifacts, such as fusion, need to be taken into consideration, these new developments in vascular biology open important therapeutic avenues. A greater understanding of how mesenchymal stem cells from the bone marrow or Artery Wall bring about vascular regeneration and repair may lead to novel cell-based treatments for cardiovascular disease.
Zhifan Gao - One of the best experts on this subject based on the ideXlab platform.
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robust estimation of carotid Artery Wall motion using the elasticity based state space approach
Medical Image Analysis, 2017Co-Authors: Zhifan Gao, Huahua Xiong, Xin Liu, Heye Zhang, Dhanjoo GhistaAbstract:Abstract The dynamics of the carotid Artery Wall has been recognized as a valuable indicator to evaluate the status of atherosclerotic disease in the preclinical stage. However, it is still a challenge to accurately measure this dynamics from ultrasound images. This paper aims at developing an elasticity-based state-space approach for accurately measuring the two-dimensional motion of the carotid Artery Wall from the ultrasound imaging sequences. In our approach, we have employed a linear elasticity model of the carotid Artery Wall, and converted it into the state space equation. Then, the two-dimensional motion of carotid Artery Wall is computed by solving this state-space approach using the H ∞ filter and the block matching method. In addition, a parameter training strategy is proposed in this study for dealing with the parameter initialization problem. In our experiment, we have also developed an evaluation function to measure the tracking accuracy of the motion of the carotid Artery Wall by considering the influence of the sizes of the two blocks (acquired by our approach and the manual tracing) containing the same carotid Wall tissue and their overlapping degree. Then, we have compared the performance of our approach with the manual traced results drawn by three medical physicians on 37 healthy subjects and 103 unhealthy subjects. The results have showed that our approach was highly correlated (Pearson’s correlation coefficient equals 0.9897 for the radial motion and 0.9536 for the longitudinal motion), and agreed well (width the 95% confidence interval is 89.62 µm for the radial motion and 387.26 µm for the longitudinal motion) with the manual tracing method. We also compared our approach to the three kinds of previous methods, including conventional block matching methods, Kalman-based block matching methods and the optical flow. Altogether, we have been able to successfully demonstrate the efficacy of our elasticity-model based state-space approach (EBS) for more accurate tracking of the 2-dimensional motion of the carotid Artery Wall, towards more effective assessment of the status of atherosclerotic disease in the preclinical stage.
-
MICCAI (3) - Carotid Artery Wall Motion Estimated from Ultrasound Imaging Sequences Using a Nonlinear State Space Approach
Lecture Notes in Computer Science, 2016Co-Authors: Zhifan Gao, Huahua Xiong, Xin Liu, Heye Zhang, Dhanjoo Ghista, Yuanyuan Sun, Yaoqin XieAbstract:It is very challenge to investigate the motion of the carotid Artery Wall in ultrasound images, because of the high nonlinear dynamics of this motion. In our study, the nonlinear dynamics of carotid Artery Wall motion is first approximated by our nonlinear state-space approach driven by a mathematical model of the mechanical deformation of carotid Artery Wall. Then, the two-dimensional motion of carotid Artery Wall is computed by solving the nonlinear state-space approach using the unscented Kalman filter. We have then evaluated the performance of our approach by comparing it with the manual tracing method (the correlation coefficient equals 0.9897 for the radial motion and 0.9703 for the longitudinal motion) and three other state-of-the-art methods for 73 subjects. The results indicate the reliable applicability of our approach in tracking the motion of the carotid Artery Wall and its potential usefulness in routine clinical diagnosis.
