The highly sensitive gammaH2AX foci assay shows that CM-enhanced radiation damage incurred in peripheral lymphocytes during CT. However, it is unknown whether long-term bioeffects of low-dose ionizing radiation from CT examinations, such as cancer, are increased by using CM.

γ-H2AX immunofluorescence microscopy allows one to determine dose-related effects on x-ray-induced DSB levels and to consider individual factors which cannot be monitored by physical dose measurements.

gamma-H2AX immunofluorescence microscopy is a reliable and sensitive method for measuring the induction and repair of DNA damage caused by ionizing radiation during angiography. To estimate radiation doses delivered during procedures and to consider patients individual repair capacity, postangiography DSB-yields should be compared with DSB-yields after fractioned in vitro irradiation imitating examination conditions.

The tested formulation of antioxidants significantly reduced formation of γ-H2AX and 53BP1 foci after irradiation at a radiologic radiation dose typical for computed tomographic imaging; administration 60 minutes prior to irradiation seems to be appropriate and leads to a significant reduction in foci.

We established an orthotopic animal model of colon cancer in mice and applied this model to study the antitumor effects of B7-H3, the newest member of the B7 family of costimulatory molecules. Colon-26 murine colon adenocarcinoma cells were inoculated into the cecal subserosum of mice to induce colon tumor growth. The tumor growth rate and the survival time of the mice were observed. A stable B7-H3 transfected Colon-26 cell line was established and the immunogenic effect was investigated. All mice implanted with wild-type tumor cells had tumor growth in the colon and died. The mean survival rate was 23 days. Mice implanted with C26-B7-H3 had a significantly prolonged survival time of 38 days. Our data suggest that B7-H3 exerts an antitumor effect on adenocarcinoma of the colon and may be considered as an adjuvant immunotherapy in the treatment of colon cancers. Our orthotopic animal model of colon cancer in mice could be applied to in vivo experimental studies of colon cancer.