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Mobin Karimi - One of the best experts on this subject based on the ideXlab platform.

  • measuring cytotoxicity by bioluminescence imaging outperforms the standard chromium 51 release assay
    PLOS ONE, 2014
    Co-Authors: Mobin Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Cynthia L Baldwin
    Abstract:

    The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI)-based cytotoxicity assay to the standard radioactive chromium-release assay using an identical set of effector cells and tumor target cells. For this, we stably transduced several human and murine tumor cell lines to express luciferase. When co-cultured with cytotoxic effector cells, highly reproducible decreases in BLI were seen in an effector to target cell dose-dependent manner. When compared to results obtained from the chromium release assay, the performance of the BLI-based assay was superior, because of its robustness, increased signal-to-noise ratio, and faster kinetics. The reduced/delayed detection of cytotoxicity by the chromium release method was attributable to the association of chromium with structural components of the cell, which are released quickly by detergent solubilization but not by hypotonic lysis. We conclude that the (BLI)-based measurement of cytotoxicity offers a superior non-radioactive alternative to the chromium-release assay that is more robust and quicker to perform.

Cynthia L Baldwin - One of the best experts on this subject based on the ideXlab platform.

  • measuring cytotoxicity by bioluminescence imaging outperforms the standard chromium 51 release assay
    PLOS ONE, 2014
    Co-Authors: Mobin Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Cynthia L Baldwin
    Abstract:

    The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI)-based cytotoxicity assay to the standard radioactive chromium-release assay using an identical set of effector cells and tumor target cells. For this, we stably transduced several human and murine tumor cell lines to express luciferase. When co-cultured with cytotoxic effector cells, highly reproducible decreases in BLI were seen in an effector to target cell dose-dependent manner. When compared to results obtained from the chromium release assay, the performance of the BLI-based assay was superior, because of its robustness, increased signal-to-noise ratio, and faster kinetics. The reduced/delayed detection of cytotoxicity by the chromium release method was attributable to the association of chromium with structural components of the cell, which are released quickly by detergent solubilization but not by hypotonic lysis. We conclude that the (BLI)-based measurement of cytotoxicity offers a superior non-radioactive alternative to the chromium-release assay that is more robust and quicker to perform.

Jean-marie Krzesinski - One of the best experts on this subject based on the ideXlab platform.

  • reproducibility of gfr measured by chromium 51 edta and iohexol
    Nephrology Dialysis Transplantation, 2008
    Co-Authors: Pierre Delanaye, Etienne Cavalier, Marc Froissart, Jean-marie Krzesinski
    Abstract:

    We read with interest the article published by Bird et al about the reproducibility of measured GFR by iohexol and Cr-51-EDTA [ 1 ]. We would like to make one comment and to share our own results on this fundamental (although understudied) topic. As we already pointed out in a NDT editorial, we share the same reserves about the opportunity to index glomerular filtration rate (GFR) with body surface area [ 2 ]. Indexing GFR with extracellular fluid volume (ECV) may be viewed as more logical as one of the major functions of the kidney is to regulate ECV. However, the fact that reproducibility of the GFR is better when indexed with ECV than when indexed with BSA is not the definite proof to use ECV indexation. The only proof would be to have an absolute correlation between GFR and ECV and that this relationship would totally disappear between indexed GFR and ECV [ 2 ]. For these reasons, we think that reproducibility of GFR measurement must be calculated from absolute, non-indexed GFR. Can Bird et al give the reproducibility of their non-indexed GFR?

Francis Mimouni - One of the best experts on this subject based on the ideXlab platform.

  • Placental calcium transport during acute maternal hypermagnesemia in the rat.
    American journal of obstetrics and gynecology, 1993
    Co-Authors: Francis Mimouni, Zahir Mughal, G. Hammond
    Abstract:

    Our aim was to test the hypothesis that maternofetal placental calcium transfer rate decreases in experimentally induced acute maternal hypermagnesemia in the rat. We measured the unidirectional maternofetal clearance of calcium 45 and chromium 51-ethylenediaminetetraacetic acid across in situ perfused placentas of rats randomized to intravenous treatment with saline solution and magnesium sulfate (n = 5) or to saline solution only (n = 5) before placental perfusion. The maternofetal clearance of chromium 51-ethylenediaminetetraacetic acid provides a measure of placental "porosity" or passive permeability. The mean serum magnesium concentration increased to 5.3 +/- 0.6 mg/dl (2.18 +/- 0.25 mmol/L) in magnesium-infused rats, staying at 1.8 +/- 0.1 mg/dl (0.74 +/- 0.04 mmol/L) in control rats (p < 0.001). Neither the maternofetal clearance of calcium 45 nor that of chromium 51-ethylenediaminetetraacetic acid was affected by acute maternal hypermagnesemia. Within the range of hypermagnesemia studied, placental calcium transport remains unaffected.

  • Placental calcium transport during acute maternal hypermagnesemia in the rat
    American Journal of Obstetrics and Gynecology, 1993
    Co-Authors: Francis Mimouni, Zahir Mughal, Gail Hammond
    Abstract:

    OBJECTIVE: Our aim was to test the hypothesis that maternofetal placental calcium transfer rate decreases in experimentally induced acute maternal hypermagnesemia in the rat. STUDY DESIGN: We measured the unidirectional maternofetal clearance of calcium 45 and chromium 51-ethylenediaminetetraacetic acid across in situ perfused placentas of rats randomized to intravenous treatment with saline solution and magnesium sulfate (n = 5) or to saline solution only (n = 5) before placental perfusion. The maternofetal clearance of chromium 51-ethylenediaminetetraacetic acid provides a measure of placental “porosity” or passive permeability. RESULTS: The mean serum magnesium concentration increased to 5.3 ± 0.6 mg/dl (2.18 ± 0.25 mmol/L) in magnesium-infused rats, staying at 1.8 ± 0.1 mg/dl (0.74 ± 0.04 mmol/L) in control rats (p CONCLUSION: Within the range of hypermagnesemia studied, placental calcium transport remains unaffected.

  • Effects of maternally administered epidermal growth factor on placental permeability
    American Journal of Obstetrics and Gynecology, 1991
    Co-Authors: Francis Mimouni, Steven B. Hoath, Gail Hammond
    Abstract:

    Epidermal growth factor is a well-studied modulator of epithelial membrane structure and function. Mammalian placentas are a rich source of epidermal growth factor receptors, but the role of epidermal growth factor in placental pathophysiologic conditions is unclear. To determine whether epidermal growth factor could affect mechanisms of placental transfer, we used an in situ rat placental perfusion model. Fourteen Sprague-Dawley rats that were 20 days pregnant were randomized to epidermal growth factor or placebo during placental transport experiments. We chose ethylenediaminetetraacetate tagged with chromium 51 as a marker of placental permeability. Epidermal growth factor treatment led to a dramatic increase of maternofetal clearances of chromium 51-ethylenediaminetetraacetate. We conclude that maternally administered epidermal growth factor has a potent action on placental permeability.

Taku Kambayashi - One of the best experts on this subject based on the ideXlab platform.

  • measuring cytotoxicity by bioluminescence imaging outperforms the standard chromium 51 release assay
    PLOS ONE, 2014
    Co-Authors: Mobin Karimi, Taku Kambayashi, Michael H Bachmann, Ana M Salicioni, Edward M. Behrens, Cynthia L Baldwin
    Abstract:

    The chromium-release assay developed in 1968 is still the most commonly used method to measure cytotoxicity by T cells and by natural killer cells. Target cells are loaded in vitro with radioactive chromium and lysis is determined by measuring chromium in the supernatant released by dying cells. Since then, alternative methods have been developed using different markers of target cell viability that do not involve radioactivity. Here, we compared and contrasted a bioluminescence (BLI)-based cytotoxicity assay to the standard radioactive chromium-release assay using an identical set of effector cells and tumor target cells. For this, we stably transduced several human and murine tumor cell lines to express luciferase. When co-cultured with cytotoxic effector cells, highly reproducible decreases in BLI were seen in an effector to target cell dose-dependent manner. When compared to results obtained from the chromium release assay, the performance of the BLI-based assay was superior, because of its robustness, increased signal-to-noise ratio, and faster kinetics. The reduced/delayed detection of cytotoxicity by the chromium release method was attributable to the association of chromium with structural components of the cell, which are released quickly by detergent solubilization but not by hypotonic lysis. We conclude that the (BLI)-based measurement of cytotoxicity offers a superior non-radioactive alternative to the chromium-release assay that is more robust and quicker to perform.