The Experts below are selected from a list of 5952 Experts worldwide ranked by ideXlab platform

David G Grier - One of the best experts on this subject based on the ideXlab platform.

  • Methods of digital Video microscopy for colloidal studies
    Journal of Colloid and Interface Science, 1996
    Co-Authors: John C Crocker, David G Grier
    Abstract:

    We describe a set of image processing algorithms for extracting quantitative data from Digitized Video microscope images of colloidal suspensions. In a typical application, these direct imaging techniques can locate submicrometer spheres to within 10 nm in the focal plane and 150 nm in depth. Combining information from a sequence of Video images into single-particle trajectories makes possible measurements of quantities of fundamental and practical interest such as diffusion coefficients and pair-wise interaction potentials. The measurements we describe in detail combine the outstanding resolution of digital imaging with Video-synchronized optical trapping to obtain highly accurate and reproducible results very rapidly.

Andrej Khandoga - One of the best experts on this subject based on the ideXlab platform.

  • in vivo imaging and quantitative analysis of leukocyte directional migration and polarization in inflamed tissue
    PLOS ONE, 2009
    Co-Authors: Christoph A Reichel, Andrej Khandoga, Peter Bihari, Markus Rehberg, Fritz Krombach
    Abstract:

    Directional migration of transmigrated leukocytes to the site of injury is a central event in the inflammatory response. Here, we present an in vivo chemotaxis assay enabling the visualization and quantitative analysis of subtype-specific directional motility and polarization of leukocytes in their natural 3D microenvironment. Our technique comprises the combination of i) semi-automated in situ microinjection of chemoattractants or bacteria as local chemotactic stimulus, ii) in vivo near-infrared reflected-light oblique transillumination (RLOT) microscopy for the visualization of leukocyte motility and morphology, and iii) in vivo fluorescence microscopy for the visualization of different leukocyte subpopulations or fluorescence-labeled bacteria. Leukocyte motility parameters are quantified off-line in Digitized Video sequences using computer-assisted single cell tracking. Here, we show that perivenular microinjection of chemoattractants [macrophage inflammatory protein-1α (MIP-1α/Ccl3), platelet-activating factor (PAF)] or E. coli into the murine cremaster muscle induces target-oriented intravascular adhesion and transmigration as well as polarization and directional interstitial migration of leukocytes towards the locally administered stimuli. Moreover, we describe a crucial role of Rho kinase for the regulation of directional motility and polarization of transmigrated leukocytes in vivo. Finally, combining in vivo RLOT and fluorescence microscopy in Cx3CR1gfp/gfp mice (mice exhibiting green fluorescent protein-labeled monocytes), we are able to demonstrate differences in the migratory behavior of monocytes and neutrophils. Taken together, we propose a novel approach for investigating the mechanisms and spatiotemporal dynamics of subtype-specific motility and polarization of leukocytes during their directional interstitial migration in vivo.

Fritz Krombach - One of the best experts on this subject based on the ideXlab platform.

  • in vivo imaging and quantitative analysis of leukocyte directional migration and polarization in inflamed tissue
    PLOS ONE, 2009
    Co-Authors: Christoph A Reichel, Andrej Khandoga, Peter Bihari, Markus Rehberg, Fritz Krombach
    Abstract:

    Directional migration of transmigrated leukocytes to the site of injury is a central event in the inflammatory response. Here, we present an in vivo chemotaxis assay enabling the visualization and quantitative analysis of subtype-specific directional motility and polarization of leukocytes in their natural 3D microenvironment. Our technique comprises the combination of i) semi-automated in situ microinjection of chemoattractants or bacteria as local chemotactic stimulus, ii) in vivo near-infrared reflected-light oblique transillumination (RLOT) microscopy for the visualization of leukocyte motility and morphology, and iii) in vivo fluorescence microscopy for the visualization of different leukocyte subpopulations or fluorescence-labeled bacteria. Leukocyte motility parameters are quantified off-line in Digitized Video sequences using computer-assisted single cell tracking. Here, we show that perivenular microinjection of chemoattractants [macrophage inflammatory protein-1α (MIP-1α/Ccl3), platelet-activating factor (PAF)] or E. coli into the murine cremaster muscle induces target-oriented intravascular adhesion and transmigration as well as polarization and directional interstitial migration of leukocytes towards the locally administered stimuli. Moreover, we describe a crucial role of Rho kinase for the regulation of directional motility and polarization of transmigrated leukocytes in vivo. Finally, combining in vivo RLOT and fluorescence microscopy in Cx3CR1gfp/gfp mice (mice exhibiting green fluorescent protein-labeled monocytes), we are able to demonstrate differences in the migratory behavior of monocytes and neutrophils. Taken together, we propose a novel approach for investigating the mechanisms and spatiotemporal dynamics of subtype-specific motility and polarization of leukocytes during their directional interstitial migration in vivo.

John C Crocker - One of the best experts on this subject based on the ideXlab platform.

  • Methods of digital Video microscopy for colloidal studies
    Journal of Colloid and Interface Science, 1996
    Co-Authors: John C Crocker, David G Grier
    Abstract:

    We describe a set of image processing algorithms for extracting quantitative data from Digitized Video microscope images of colloidal suspensions. In a typical application, these direct imaging techniques can locate submicrometer spheres to within 10 nm in the focal plane and 150 nm in depth. Combining information from a sequence of Video images into single-particle trajectories makes possible measurements of quantities of fundamental and practical interest such as diffusion coefficients and pair-wise interaction potentials. The measurements we describe in detail combine the outstanding resolution of digital imaging with Video-synchronized optical trapping to obtain highly accurate and reproducible results very rapidly.

Ariane L Herrick - One of the best experts on this subject based on the ideXlab platform.

  • computerized nailfold Video capillaroscopy a new tool for assessment of raynaud s phenomenon
    The Journal of Rheumatology, 2005
    Co-Authors: Marina E Anderson, Danny P Allen, Tonia Moore, Val Hillier, C Taylor, Ariane L Herrick
    Abstract:

    OBJECTIVE: To develop a computer based nailfold Video capillaroscopy system with enhanced image quality and to assess its disease-subgroup resolving power in patients with primary and secondary Raynaud9s phenomenon (RP). METHODS: Using frame registration software, Digitized Video images from the microscope were combined to form a panoramic mosaic of the nailfold. Capillary dimensions (apex, arterial, venous, and total width) and density were measured onscreen. Significantly, the new system could guarantee analysis of the same set of capillaries by 2 observers. Forty-eight healthy control subjects, 21 patients with primary RP, 40 patients with limited cutaneous systemic sclerosis (lcSSc), and 11 patients with diffuse cutaneous SSc (dcSSc) were studied. Intra- and interobserver variability were calculated in a subset of 30 subjects. RESULTS: The number of loops/mm was significantly lower, and all 4 capillary dimensions significantly greater, in SSc patients versus controls plus primary RP patients (p

  • computerized nailfold Video capillaroscopy a new tool for assessment of raynaud s phenomenon
    The Journal of Rheumatology, 2005
    Co-Authors: Marina E Anderson, Danny P Allen, Tonia Moore, Val Hillier, C Taylor, Ariane L Herrick
    Abstract:

    OBJECTIVE: To develop a computer based nailfold Video capillaroscopy system with enhanced image quality and to assess its disease-subgroup resolving power in patients with primary and secondary Raynaud's phenomenon (RP). METHODS: Using frame registration software, Digitized Video images from the microscope were combined to form a panoramic mosaic of the nailfold. Capillary dimensions (apex, arterial, venous, and total width) and density were measured onscreen. Significantly, the new system could guarantee analysis of the same set of capillaries by 2 observers. Forty-eight healthy control subjects, 21 patients with primary RP, 40 patients with limited cutaneous systemic sclerosis (lcSSc), and 11 patients with diffuse cutaneous SSc (dcSSc) were studied. Intra- and interobserver variability were calculated in a subset of 30 subjects. RESULTS: The number of loops/mm was significantly lower, and all 4 capillary dimensions significantly greater, in SSc patients versus controls plus primary RP patients (p < 0.001 for all measures). When comparing control (+ primary RP) patients with SSc patients (lcSSc + dcSSc) the most powerful discriminator was found to be the number of loops/mm. Results for intra- and interobserver reproducibility showed that the limits of agreement were closer when both observers measured the same capillaries. CONCLUSION: The key feature of the newly developed system is that it improves reproducibility of nailfold capillary measurements by allowing reidentification of the same capillaries by different observers. By allowing access to previous measurements, the new system should improve reliability in longitudinal studies, and therefore has the potential of being a valuable outcome measure of microvessel disease/involvement in clinical trials of scleroderma spectrum disorders.