A new approach to automated CBMN scoring following high doses

Abstract

In recent years we have automated the CBMN assay using microvolumes of blood, processed in multiwell plates. We have seen that at doses above 6 Gy the detected yield of micronuclei actually declines with dose, likely because of mitotic delay, preventing cells from forming micronuclei and also, when using one color imaging, resulting in many false binucleated cells, consisting of two randomly-adjacent nuclei. By using the inverse mitotic index (the ratio of mononuclear to binuclear cells) to adjust the micronucleus yield we were able to obtain a monotonic increasing dose response curve at doses of up to at least 10 Gy from the same samples which generated dose-response curve with a peak near 6 Gy, when scored using the traditional micronucleus yield.

The Use of Image Processing and Analysis in Automated Biological Dosimetry

“…A secondary staining to identify the boundaries of each cell can also be performed, although this step is often omitted, likely because it significantly reduces throughput. More commonly, MN associated with the nucleus are predicted using the proximity method [20].…”

“…A research group from the Center for High-Throughput Minimally Invasive Radiation Biodosimetry at Columbia University has developed a robotic platform called Robotic Automated Biodosimetry Technology (RABiT) for the highthroughput processing of cytogenetic biodosimetry techniques, such as the CBMN assay and DCA [19,20]. In several of their recent publications, this group has described the development of RABiT-II, with the aim to implement standard cytogenetic assays in a 96-well plate format and analyzing them using commercial, automated, high-throughput screening platforms.…”