51Cr release

Exposure of various cells to ROIs (H2O2, OC1-) in vitro causes a multitude of biochemical alterations including (a) loss of intracellular ATP and NAD+, (b) stimulation of HMP shunt activity, (c) DNA strand breakage, (d) increase in oxidized protein thiol groups, (e) increase in intracellular Ca2+, (f) activation of poly(ADP-ribose) polymerase, (g) alterations in cell morphology, (h) inhibition of many biosynthetic pathways, (i) 51Cr release, (j) intracellular enzyme... 

Kim GGG, Donnenberg VSV, Donnenberg ADA, Gooding WW, Whiteside TLT (2007) A novel multiparametric flow cytometry-based cytotoxicity assay simultaneously immunophenotypes effector cells comparisons to a 4 h 51Cr-release assay. J Immunol Methods 325 16-66... 

Natural killer (NK) cells are a subpopulation of lymphocytes that can lyse a wide variety of tumor cells and some normal cells. They are classified as null cells, being neither B or T cells. The assay usually is an in vitro one in which target cells, labeled with 51Cr are exposed to the NK cell population, and the amount of radioactive 51Cr released is measured. NK cell activity is highest in young animals (mice 5-8 weeks of age), and is present in very low levels, if at all, in older animals. However, when older rats were exposed to C. parvum or BCG, there was an increase in the cytotoxicity of the lymphocyte population. 

Lymphocyte cell subset enumeration was done by the use of suitable fluorescent labeled monoclonal antibodies and a fluorescence activated cell sorter. Cytolytic activity of NK cells was tested against K562 cells, using a standard 51Cr release assay. 

Some cytotoxicity assays, such as dye incorporation by dead cells or 51Cr or fluorescein release by labeled cells, offer instantaneous results and are named viability tests. These tests are adequate for the identification of dead cells, but can overestimate cell survival over longer periods. Most of them cause membrane rupture and cell death. 

Evaluation of membrane integrity is the most commonly used measurement of cell viability, indicating instantaneous or progressive damage over a few hours, and can be performed by 51Cr or specific enzymes release or a dye exclusion assay. These assays are particularly important for toxic agents that exert a primary effect on membrane integrity. Nevertheless, quantification can be difficult due to cell loss by surface detachment or autolysis. 

Colsky AS, Peacock JS. 1990. Sodium pyruvate inhibits the spontaneous release of 51Cr from RBC in chromium release assays. J Immunol Methods 129 139-141. 

The radioactive chromium (51Cr) found in Columbia River sediments contaminated with effluent from a nuclear reactor facility was not released by the major cations of sea water or by 0.05 M CuS0424 . The results of previous work in this laboratory (New England Aquarium) showed that of the silver(I) and cadmium(II) adsorbed on the clay minerals kaolin and montmorillonite, in essentially deionized water, less than half was desorbed on mixing with sea water25 . One may postulate from results such as these that most of the heavy metals occluded within a complex organic... 

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