Scintillation autofluorographic assessment of isotope uptake in human glioma cells grown on microtitration plates using sodium salicylate.

We describe a simple method for detecting [35S]methionine-labeled protein in fixed human astrocytoma cells grown in 96-well microtitration plates using a modified scintillation autofluorographic method. Following isotopic labeling, cells are fixed in situ and a solution of salicylic acid in methanol is dried onto the cell layer. The fluorographic image is detected using blue-sensitive X-ray film attached to the base of the plate which, following development, can be quantitated using a scanning densitometer. The relationship between cell number and optical density is linear, and there is a close correlation between the dose-response curves generated by this method and alternative isotopic detection methods and cell counting. This assay provides a suitable alternative to the use of potentially toxic scintillation fluids based on organic solvents like toluene or xylene in chemosensitivity testing of human brain tumors.