Cellular recognition of DNA damage and the subsequent repair processes may differ between neutrons and photons. Here we used the cytokinesis-block micronucleus assay to address the question whether neutrons induce a bystander effect in normal human lymphoblastoid cell lines. These data indicate that neutrons do not induce a bystander effect in these cells. Knowing the RBE is important for radiation oncologists to determine the dose prescription and the most effective radiotherapy treatment plan for cancer patients. [56] suggested that the gamma ray-induced bystander effect might have been suppressed by the neutron exposures. The same is true for tumours of the skin and subcutaneous tissue at a dose of 85 rad. Neutrons, depending on their energy, might be more effective in controlling certain tumor types where conventional photon therapy is ineffective [63] because the oxygen enhancement ratio, i.e. No bridges were observed in the 4% confidence intervals. Normal human lymphoblastoid cell lines (GM15036 and GM15510) obtained from the Coriell Cell Repository were used for these experiments because they have previously been shown to exhibit a bystander effect in response to gamma radiation [22], [24]. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. Buds were counted only if the stalk was thinner than the widest part of the bud. Ionizing radiation is also an effective method for treating tumors because it can be localized to the tumor and is a potent inducer of DNA double-strand breaks, a highly toxic form of DNA damage. These results suggest that a neutron bystander effect may be comprised of gene mutations. However, if a very small bystander effect was in fact induced by neutrons, then it may have been obscured by the DMSO, whereas the bystander effect induced by high levels of photons was too large to be masked by DMSO. The same set of analyses were performed for the neutron bystander data which included replicate experiments as an additional variable. Yang et al. It is very low. While many exist in nature, the majority are created in nuclear reactionsa. Four case series and a new case report have been published reporting the impact of HBOT as a treatment for radiation necrosis of the larynx. Both pre- and post-radiation treatment with DMSO is known to suppress DNA damage in irradiated cells [66]. S103-S110. The transportation control involved flasks that were transported with the cells that were irradiated, but remained inside the insulated box; these control flasks were further insulated with bubble wrap to maintain their temperature close to 37°C. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy), and irradiated-cell conditioned media (ICCM) was transferred to unirradiated cells. For each cell line, the neutron bystander experiment was performed twice, once each on different days. Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America, Affiliation Is the Subject Area "Micronuclei" applicable to this article? For the endpoints of micronuclei and nucleoplasmic bridges, we found no evidence to indicate that neutrons induce a bystander effect in normal human lymphoblastoid cells. It is also a problem in nuclear fissi… Neutron irradiation to high fluence will lead to changes in the properties of the structural materials. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The media-only control had values similar to the 0 Gy (control) for both endpoints. Radiation that produces light in order for photosynthesis to occur is a positive effect that radiation has on plant life 3⭐⭐This is a verified and trusted source Goto Source . However, this possibility seems unlikely in the work described here because we observed a bystander effect with an identical procedure involving DMSO when the same cell lines were exposed to photons. Since serotonin has been reported to play a role in the bystander effect [49] and is light sensitive, the bottles containing the culture media were wrapped in aluminum foil and stored in the dark. However, if the damage is not repaired correctly, a cell may die or eventually become cancerous. https://doi.org/10.1371/journal.pone.0098947.g004. here. However alpha particles will deposit their energy over a smaller volume (possibly only a few cells if they enter a body) and cause more damage to those few cells. [40] observed a significant decrease in the number of DNA double-strand breaks, micronuclei frequencies, and the extent of apoptosis in irradiated cells that were co-cultured with unirradiated bystander cells. [71] reported RBEs of 2.35 and 2.42 for fast neutrons in immature rat hippocampal cells, as determined by two different cell viability assays. The neutron beam is shaped by a primary collimator composed of iron and a secondary collimator made up of individually movable leaves composed of iron with cylindrical polyethylene inserts. Other sources of low level neutron irradiation may include occupational exposure to workers at nuclear power plants and accelerator facilities, astronauts, airline crews and passengers on high altitude flights [3]–[14], as well as radiation incidents such as the Hiroshima-Nagasaki atomic bomb explosions and the tsunami-induced radiation leak at the Fukushima Daiichi site in Japan [15]. Even though a bystander effect was not observed with the neutron exposures, we sought to determine whether photons might cause a bystander effect at the doses employed in these experiments. In addition, late effects such as chromosomal instability may increase susceptibility to cancer [21]. 0.2 Gy. With our data it is difficult to determine whether neutrons have the ability to suppress any bystander effect produced by photons because a source of uncontaminated neutrons is not available. C. Medvedovsky and B. V. Worgul (1991) Neutron Effects on the Lens.Radiation Research: October 1991, Vol. Hence, reevaluation of radiation protection standards may be required. The principal kinds of ionizing radiation are: The cell cultures were then incubated at 37°C for 28 hours. But the neutronic flash does not last. For experiments reported in this work, the average neutron energy is about 17 MeV, and the neutron mean free path in water is about 9 cm. Thus, cells that are directly damaged are not the sole targets of radiation exposure. The Tukey HSD test was used for post-hoc evaluations. Affiliation For more information about PLOS Subject Areas, click Neutrons were listed as a carcinogen for the first time in the Eleventh Report on Carcinogens [2]. For each experiment, the independent variables considered were cell line, dose, and the interaction between cell line and dose. 1s, pp. Vertical lines represent the 95% confidence intervals. Biomedical/nuclear engineer ely5: While gamma or Xray radiation is just photons that have to rely on funny electric and quantum effects to manipulate the "macro" word, neutrons are large enough to act like actual projectiles to molecules of smaller atoms (e.g. Citation: Seth I, Schwartz JL, Stewart RD, Emery R, Joiner MC, Tucker JD (2014) Neutron Exposures in Human Cells: Bystander Effect and Relative Biological Effectiveness. Understanding the biological effects of neutrons may also enable more refined evaluations of the standards for radiation protection and safety. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001). https://doi.org/10.1371/journal.pone.0098947.g001. These may include diarrhea, headache, hair loss, skin burns and poor healing, according to the Mayo Clinic 1.cause: These may include diarrhea The 1 Gy data are missing for GM15510 cells replicate 2 because the sample was lost. 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