The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform

Jeffrey Atkinson - One of the best experts on this subject based on the ideXlab platform.

  • Activation of metalloproteinase-2, loss of matrix Scleroprotein content and coronary artery calcification
    Atherosclerosis, 2001
    Co-Authors: Pascal Kieffer, Philippe Giummelly, Bruno Schjoth, Jean Pierre Carteaux, Jean Pierre Villemot, William Hornebeck, Jeffrey Atkinson
    Abstract:

    Plaques from the coronary arteries of explanted hearts showed massive calcification (15-fold increase) with a loss of Scleroproteins (-36%), an increase in the collagen to elastin ratio (twofold) and activation (+15%) of matrix metalloproteinase-2 (MMP-2). Plaque-free portions of the coronary artery gave results similar to those obtained with the internal mammary artery. There was a significant correlation between plaque calcification and MMP-2 activation, suggesting that the two processes may be linked.

  • Elastic properties and composition of the aortic wall in old spontaneously hypertensive rats.
    Hypertension (Dallas Tex. : 1979), 1999
    Co-Authors: Valérie Marque, Pascal Kieffer, Jeffrey Atkinson, Isabelle Lartaud-idjouadiene
    Abstract:

    We hypothesized that age-linked changes in the composition and elastic properties of the arterial wall occur earlier in hypertensive than in normotensive rats. We evaluated the consequences of hypertension and aging on aortic mechanics, geometry, and composition in 3-, 9-, and 15-month-old awake Wistar-Kyoto rats (WKY) (normotensive) and spontaneously hypertensive rats (SHR) (hypertensive). The elastic modulus of the thoracic aorta, calculated from aortic pulse wave velocity and geometry, was higher in young and adult SHR than in age-matched WKY, as was wall stress; however, isobaric pulse wave velocity and pulse wave velocity-pressure curves were similar. Elastic modulus, isobaric pulse wave velocity, and the slope of the pulse wave velocity-pressure curve dramatically increased in old SHR compared with age-matched WKY; there was no further elevation of blood pressure or wall thickness. Fibrosis did not develop with age in SHR, and the ratio of elastin to collagen decreased in a similar fashion with aging in both strains. In conclusion, although elastic properties of the aortic wall are not intrinsically modified in young and adult SHR in comparison to age-matched WKY, aging is associated with a dramatic stiffening of the aortic wall in old SHR but not in WKY. Changes in blood pressure, aortic wall geometry, or Scleroprotein composition do not appear to explain this age-linked aortic stiffening in SHR, suggesting that other mechanisms of disorganization of the media may be involved.

Nancy R. Forde - One of the best experts on this subject based on the ideXlab platform.

  • Probing the Mechanical Properties of Single Scleroproteins with Optical Tweezers
    Biophysical Journal, 2010
    Co-Authors: Benjamin P. B. Downing, Astrid Van Der Horst, Ming Miao, Fred W. Keeley, Nancy R. Forde
    Abstract:

    Stretching and relaxing single proteins provides quantitative information on their elasticity and other mechanical properties. This can be done with optical tweezers, a technique in which the ends of the protein are chemically attached to micron-scale spheres, used to manipulate the protein and measure its response. We are working on the application of this technique to Scleroproteins, nonglobular proteins whose mechanical properties are of direct relevance to their physiological roles. These proteins self-assemble into hierarchically organized load-bearing structures, often found in the extracellular matrix. The ability of optical tweezers to manipulate single molecules and higher-order structures suggests their application to probing the mechanical response at different hierarchies of assembly. Applying this technique to stretch these single proteins presents many challenges, including the production of constructs with appropriate labels for attachment to microspheres, relatively short contour lengths which can introduce experimental artifacts, and self-aggregation and binding interactions of these predominantly insoluble proteins, which make it difficult to isolate and manipulate single molecules. We discuss our work to overcome these challenges, with a specific focus on elastin.

Pascal Kieffer - One of the best experts on this subject based on the ideXlab platform.

  • Activation of metalloproteinase-2, loss of matrix Scleroprotein content and coronary artery calcification
    Atherosclerosis, 2001
    Co-Authors: Pascal Kieffer, Philippe Giummelly, Bruno Schjoth, Jean Pierre Carteaux, Jean Pierre Villemot, William Hornebeck, Jeffrey Atkinson
    Abstract:

    Plaques from the coronary arteries of explanted hearts showed massive calcification (15-fold increase) with a loss of Scleroproteins (-36%), an increase in the collagen to elastin ratio (twofold) and activation (+15%) of matrix metalloproteinase-2 (MMP-2). Plaque-free portions of the coronary artery gave results similar to those obtained with the internal mammary artery. There was a significant correlation between plaque calcification and MMP-2 activation, suggesting that the two processes may be linked.

  • Elastic properties and composition of the aortic wall in old spontaneously hypertensive rats.
    Hypertension (Dallas Tex. : 1979), 1999
    Co-Authors: Valérie Marque, Pascal Kieffer, Jeffrey Atkinson, Isabelle Lartaud-idjouadiene
    Abstract:

    We hypothesized that age-linked changes in the composition and elastic properties of the arterial wall occur earlier in hypertensive than in normotensive rats. We evaluated the consequences of hypertension and aging on aortic mechanics, geometry, and composition in 3-, 9-, and 15-month-old awake Wistar-Kyoto rats (WKY) (normotensive) and spontaneously hypertensive rats (SHR) (hypertensive). The elastic modulus of the thoracic aorta, calculated from aortic pulse wave velocity and geometry, was higher in young and adult SHR than in age-matched WKY, as was wall stress; however, isobaric pulse wave velocity and pulse wave velocity-pressure curves were similar. Elastic modulus, isobaric pulse wave velocity, and the slope of the pulse wave velocity-pressure curve dramatically increased in old SHR compared with age-matched WKY; there was no further elevation of blood pressure or wall thickness. Fibrosis did not develop with age in SHR, and the ratio of elastin to collagen decreased in a similar fashion with aging in both strains. In conclusion, although elastic properties of the aortic wall are not intrinsically modified in young and adult SHR in comparison to age-matched WKY, aging is associated with a dramatic stiffening of the aortic wall in old SHR but not in WKY. Changes in blood pressure, aortic wall geometry, or Scleroprotein composition do not appear to explain this age-linked aortic stiffening in SHR, suggesting that other mechanisms of disorganization of the media may be involved.

Benjamin P. B. Downing - One of the best experts on this subject based on the ideXlab platform.

  • Probing the Mechanical Properties of Single Scleroproteins with Optical Tweezers
    Biophysical Journal, 2010
    Co-Authors: Benjamin P. B. Downing, Astrid Van Der Horst, Ming Miao, Fred W. Keeley, Nancy R. Forde
    Abstract:

    Stretching and relaxing single proteins provides quantitative information on their elasticity and other mechanical properties. This can be done with optical tweezers, a technique in which the ends of the protein are chemically attached to micron-scale spheres, used to manipulate the protein and measure its response. We are working on the application of this technique to Scleroproteins, nonglobular proteins whose mechanical properties are of direct relevance to their physiological roles. These proteins self-assemble into hierarchically organized load-bearing structures, often found in the extracellular matrix. The ability of optical tweezers to manipulate single molecules and higher-order structures suggests their application to probing the mechanical response at different hierarchies of assembly. Applying this technique to stretch these single proteins presents many challenges, including the production of constructs with appropriate labels for attachment to microspheres, relatively short contour lengths which can introduce experimental artifacts, and self-aggregation and binding interactions of these predominantly insoluble proteins, which make it difficult to isolate and manipulate single molecules. We discuss our work to overcome these challenges, with a specific focus on elastin.

Yvonne Joseph - One of the best experts on this subject based on the ideXlab platform.

  • Marine Spongin: Naturally Prefabricated 3D Scaffold-Based Biomaterial.
    Marine Drugs, 2018
    Co-Authors: Teofil Jesionowski, Małgorzata Norman, Sonia Żółtowska-aksamitowska, Iaroslav Petrenko, Yvonne Joseph
    Abstract:

    The biosynthesis, chemistry, structural features and functionality of spongin as a halogenated Scleroprotein of keratosan demosponges are still paradigms. This review has the principal goal of providing thorough and comprehensive coverage of spongin as a naturally prefabricated 3D biomaterial with multifaceted applications. The history of spongin’s discovery and use in the form of commercial sponges, including their marine farming strategies, have been analyzed and are discussed here. Physicochemical and material properties of spongin-based scaffolds are also presented. The review also focuses on prospects and trends in applications of spongin for technology, materials science and biomedicine. Special attention is paid to applications in tissue engineering, adsorption of dyes and extreme biomimetics.