The accepted paradigm for radiation effects is that direct DNA damage via energy deposition is required to trigger the downstream biological consequences. The radiation-induced bystander effect is the ability of directly irradiated cells to interact with their nonirradiated neighbors, which can then show responses similar to those of the targeted cells. p53 binding protein 1 (53BP1) forms foci ...

The radiation-induced bystander effect is the phenomenon which non-irradiated cells exhibit effects along with their different levels as a result of signals received from nearby irradiated cells. Responses of non-irradiated cells may include changes in process of translation, gene expression, cell proliferation, apoptosis and cells death. These changes are confirmed by results of some In-Vivo s...

Chloroethylnitrosourea (CENU) chemotherapy is used for the treatment of melanoma tumors. The main mechanism of action of this anticancer agent is via DNA damage. We recently showed in murine experiments using a parental double B16 melanoma tumor model that, after treatment of primary tumors with cystemustine (CENU agent), untreated secondary tumors exhibited growth inhibition and metabolism dis...

Background The intention of cancer chemotherapy is to control the growth of cancer cells using chemical agents. However, the occurrence of second malignancies has raised concerns, leading to re-evaluation of the current strategy in use for chemotherapeutic agents. Although the mechanisms involved in second malignancy remain ambiguous, therapeutic-agent-induced non-DNA targeted effects like byst...

background: in this study, the bystander effect of radiation was evaluated on the regulation of cox-2, inos, and 8-ohdg in the lung tissues of sprague-dawley rats with and without pre-administration of melatonin. materials and methods: a 2×2 cm area of the pelvis of male sprague-dawley rats with and without pre-administration of melatonin (100 mg/kg) by oral and ip injection was irradiated with...

Currently, interactions between voxels are neglected in the tumor control probability (TCP) models used in biologically-driven intensity-modulated radiotherapy treatment planning. However, experimental data suggests that this may not always be justified when bystander effects are important. We propose a model inspired by the Ising model, a short-range interaction model, to investigate if and wh...

This study examined the bystander effect in cyberbullying. Using self-reported data from 257 Czech respondents who had witnessed a cyberbullying attack, we tested whether provided help decreased with increased number of other bystanders. We controlled for several individual and contextual factors, including empathy, social self-efficacy, empathic response to victimization, and relationship to t...

Although radiation-induced bystander effects have been well described over the past decade, the mechanisms of the signaling processes involved in the bystander phenomenon remain unclear. In the present study, using the Columbia University charged particle microbeam, we found that mitochondrial DNA-depleted human skin fibroblasts (rho(o)) showed a higher bystander mutagenic response in confluent...

Although radiation-induced bystander effects have been well described over the past decade, the mechanisms of the signaling processes involved in the bystander phenomenon remain unclear. In the present study, using the Columbia University charged particle microbeam, we found that mitochondrial DNA–depleted human skin fibroblasts (R) showed a higher bystander mutagenic response in confluent mono...

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/...