A long-held central dogma of radiation biology has been that the carcinogenic effects of ionizing radiation (IR) are induced by the direct and radiolytic actions of IR on nuclear DNA. Numerous investigations, however, have revealed that several cancer relevant effects of IR can occur in cells that have received only cytoplasmic or plasmalemmal membrane exposure to IR. Further, mounting evidence...

A protective effect of exogenous carbon monoxide (CO), generated by CO releasing molecule ticarbonyldichlororuthenium (II) dimer (CORM-2), on the bystander cells from the toxicity of radiation-induced bystander effect (RIBE) was revealed in our previous study. In the present work, a possible mechanism of this CO effect was investigated. The results from medium transfer experiments showed that α...

Densely ionizing (high-LET) galactic cosmic rays (GCR) contribute a significant component of the radiation risk in free space. Over a period of a few months-sufficient for the early stages of radiation carcinogenesis to occur-a significant proportion of cell nuclei will not be traversed. There is convincing evidence, at least in vitro, that irradiated cells can send out signals that can result ...

The radiation-induced bystander effect (RIBE) is a phenomenon whereby unexposed cells exhibit molecular symptoms of stress exposure when adjacent or nearby cells are traversed by ionizing radiation (IR). Recent data suggest that RIBE may be epigenetically mediated by microRNAs (miRNAs), which are small regulatory molecules that target messenger RNA transcripts for translational inhibition. Here...

It has long been accepted that radiation-induced genetic effects require that DNA be hit and damaged directly by the radiation. Recently, evidence has accumulated that in cell populations exposed to low doses of alpha particles, biological effects occur in a larger proportion of cells than are estimated to have been traversed by alpha particles. The end points observed include chromosome aberra...

Ever since the discovery of X-rays was made by Röntgen more than a hundred years ago, it has always been accepted that the deleterious effects of ionizing radiation such as mutation and carcinogenesis are attributable mainly to direct damage to DNA. Although evidence based on microdosimetric estimation in support of a bystander effect appears to be consistent, direct proof of such extranuclear/...

The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and non-targeted effects. The exogenous NO was generated using an NO donor, S-nitroso-N-acetylpenicillamine (SNAP). The...

Untargeted effects of ionizing radiation (de novo effects in the unirradiated descendants or neighbors of irradiated cells) challenge widely held views about the mechanisms of radiation-induced DNA damage with implications for the health consequences of radiation exposures particularly in the context of the induction of malignancy. To investigate in vivo untargeted effects of sparsely ionizing ...