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Radiation and Environmental Biophysics

Mikhail Sokolnikov, Dale Preston, Daniel O Stram
Exposure to ionizing radiation has well-documented long-term effects on cancer rates and other health outcomes in humans. While in vitro experimental studies had demonstrated that the nature of some radiation effects depend on both total dose of the radiation and the dose rate (i.e., the pattern of dose distribution over time), the question of whether or not the carcinogenic effect of radiation exposure depends on the dose rate remains unanswered. Another issue of interest concerns whether or not concomitant exposure to external gamma rays and inhaled plutonium aerosols has any effect on the external exposure effects...
September 30, 2016: Radiation and Environmental Biophysics
Atefeh Rostami, Mohammad Thaghi Bahreyni Toossi, Ameneh Sazgarnia, Shokouhozaman Soleymanifard
Due to biocompatibility and relative non-toxic nature, gold nanoparticles (GNPs) have been studied widely to be employed in radiotherapy as radio-sensitizer. On the other hand, they may enhance radiation-induced bystander effect (RIBE), which causes radiation adverse effects in non-irradiated normal cells. The present study was planned to investigate the possibility of augmenting the RIBE consequence of applying glucose-coated gold nanoparticles (Glu-GNPs) to target cells. Glu-GNPs were synthesized and utilized to treat MCF7 and QUDB cells...
September 9, 2016: Radiation and Environmental Biophysics
E A Shishkina, A Yu Volchkova, Y S Timofeev, P Fattibene, A Wieser, D V Ivanov, V A Krivoschapov, V I Zalyapin, S Della Monaca, V De Coste, M O Degteva, L R Anspaugh
This study summarizes the 20-year efforts for dose reconstruction in tooth enamel of the Techa riverside residents exposed to ionizing radiation as a result of radionuclide releases into the river in 1949-1956. It represents the first combined analysis of all the data available on EPR dosimetry with teeth of permanent residents of the Techa riverside territory. Results of electron paramagnetic resonance (EPR) measurements of 302 teeth donated by 173 individuals living permanently in Techa riverside settlements over the period of 1950-1952 were analyzed...
September 6, 2016: Radiation and Environmental Biophysics
Paul J Black, Adam S Miller, Jeffrey J Hayes
As humans, we are constantly exposed to ionizing radiation from natural, man-made and cosmic sources which can damage DNA, leading to deleterious effects including cancer incidence. In this work, we introduce a method to monitor strand breaks resulting from damage due to the direct effect of ionizing radiation and provide evidence for sequence-dependent effects leading to strand breaks. To analyze only DNA strand breaks caused by radiation damage due to the direct effect of ionizing radiation, we combined an established technique to generate dehydrated DNA samples with a technique to analyze single-strand breaks on short oligonucleotide sequences via denaturing gel electrophoresis...
November 2016: Radiation and Environmental Biophysics
Linda Walsh, Uwe Schneider
Determinations of the lowest colon dose, D min, below which there is a statistically significant excess relative risk of all solid cancer, when analyses are restricted to the range [0, D min], are of current interest in research related to radiation protection and risk assessment. In reviewing recent cancer mortality reports on the Life Span Study (LSS) of Japanese A-bomb survivors, reported D min values were found to vary between different reports. The report 12 (follow-up: 1950-1990) found a D min of 50 mGy, but the most recent report 14 (follow-up: 1950-2003) found a D min of 200 mGy...
September 1, 2016: Radiation and Environmental Biophysics
S Nishad, Anu Ghosh
Ionizing radiation (IR) is considered ubiquitous in nature. The immediate early genes are considered the earliest nuclear targets of IR and are induced in the absence of de novo protein synthesis. Many of these genes encode transcription factors that constitute the first step in signal transduction to couple cytoplasmic effects with long-term cellular response. In this paper, coordinated transcript response of fos and jun family members which constitute activator protein 1 transcription factor was studied in response to IR in human peripheral blood lymphocytes at the G0 stage...
September 1, 2016: Radiation and Environmental Biophysics
Miao Hu, Nan Hu, Dexin Ding, Weichao Zhao, Yongfu Feng, Hui Zhang, Guangyue Li, Yongdong Wang
This study aimed to evaluate the biological effects of gamma irradiation on zebrafish embryos. Different doses of gamma rays (0.01, 0.05, 0.1, 0.5 and 1 Gy) were used to irradiate zebrafish embryos at three developmental stages (stage 1, 6 h post-fertilization (hpf); stage 2, 12 hpf; stage three, 24 hpf), respectively. The survival, malformation and hatching rates of the zebrafish embryos were measured at the morphological endpoint of 96 hpf. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx) and glutathione S-transferase (GST) were assayed...
August 31, 2016: Radiation and Environmental Biophysics
Verónica A Trivillin, Leandro J Bruno, David A Gatti, Mariela Stur, Marcela A Garabalino, Andrea Monti Hughes, Jorge Castillo, Emiliano C C Pozzi, Luis Wentzeis, Hugo Scolari, Amanda E Schwint, Sara Feldman
Rheumatoid arthritis is a chronic autoimmune pathology characterized by the proliferation and inflammation of the synovium. Boron neutron capture synovectomy (BNCS), a binary treatment modality that combines the preferential incorporation of boron carriers to target tissue and neutron irradiation, was proposed to treat the pathological synovium in arthritis. In a previous biodistribution study, we showed the incorporation of therapeutically useful boron concentrations to the pathological synovium in a model of antigen-induced arthritis (AIA) in rabbits, employing two boron compounds approved for their use in humans, i...
August 27, 2016: Radiation and Environmental Biophysics
Murat Kurudirek
The objective of this work was to study water- and tissue-equivalent properties of some gel dosimeters, human tissues and water, for scattering of photons using the effective atomic number (Z eff). The Rayleigh to Compton scattering ratio (R/C) was used to obtain Z eff and electron density (N e ) of gel dosimeters, human tissues and water considering a 10(-2)-10(9) momentum transfer, q (Å(-1)). In the present work, a logarithmic interpolation procedure was used to estimate R/C as well as Z eff of the chosen materials in a wide scattering angle (1°-180°) and energy range (0...
August 27, 2016: Radiation and Environmental Biophysics
Engy R Rashed, Menna A El-Daly, Sawsan A Abd-Elhalim, Mona A El-Ghazaly
The current study aimed to investigate the effect of different low doses of gamma irradiation on hyperglycemia-induced brain injury. The aim was further extended to investigate the sub-chronic effect of low dose radiation on the neuronal damage induced by diabetes. To induce diabetes, male albino rats were injected with dexamethasone (10 mg/kg/day, for 9 successive days, subcutaneously). Different diabetic groups were irradiated with 0.1, 0.25 and 0.5 Gy. The effect of low dose gamma irradiation on the hyperglycemia-induced brain damage based was analyzed at two levels: oxidative stress and apoptosis...
August 26, 2016: Radiation and Environmental Biophysics
Mohammad Halimi, Ahmad Shahabi, Dariush Moslemi, Hadi Parsian, S Mohsen Asghari, Reyhaneh Sariri, Farshid Yeganeh, Ebrahim Zabihi
Radiation exposure in industrial accidents or nuclear device attacks is a major public health concern. There is an urgent need for markers that rapidly identify people exposed to ionizing radiation (IR). Finding a blood-based marker is advantageous because of the ease of sample collection. This study was designed to test the hypothesis that serum miR-34a could serve as an indicator of exposure to IR. Therefore, 44 women with breast cancer, where radiotherapy was part of their therapeutic protocol, were investigated in this study...
August 25, 2016: Radiation and Environmental Biophysics
Wolfgang-Ulrich Müller, Augusto Giussani, Werner Rühm, Jean-Francois Lecomte, John Harrison, Michaela Kreuzer, Christina Sobotzki, Joachim Breckow
ICRP suggested a strategy based on the distinction between a protection approach for dwellings and one for workplaces in the previous recommendations on radon. Now, the Commission recommends an integrated approach for the protection against radon exposure in all buildings irrespective of their purpose and the status of their occupants. The strategy of protection in buildings, implemented through a national action plan, is based on the application of the optimisation principle below a derived reference level in concentration (maximum 300 Bq m(-3))...
August 2016: Radiation and Environmental Biophysics
I Zaballa, M Eidemüller
Lung cancer mortality after radon exposure in the Wismut cohort was analyzed using the two-stage clonal expansion (TSCE) model. A total of 2996 lung cancer deaths among the 58,695 male workers were observed during the follow-up period between 1946 and 2003. Adjustment to silica exposure was performed to find a more accurate estimation of the risk of radon exposure. An additional analysis with the descriptive excess relative risk (ERR) model was carried out for comparison. The TSCE model that best describes the data is nonlinear in the clonal expansion with radon exposure and has a saturation level at an exposure rate of [Formula: see text]...
August 2016: Radiation and Environmental Biophysics
Parminder Singh, Komal Saini, Rosaline Mishra, Bijay Kumar Sahoo, Bikramjit Singh Bajwa
In this study, measurements of indoor radon ((222)Rn), thoron ((220)Rn) and their equilibrium equivalent concentration (EEC) were carried out in 96 dwellings from 22 different villages situated in Hamirpur district, Himachal Pradesh, India, by using LR-115 type II-based pinhole twin cup dosimeters and deposition-based progeny sensors (DRPS/DTPS). The annual average indoor (222)Rn and (220)Rn concentrations observed in these dwellings were 63.82 and 89.59 Bq/m(3), respectively, while the average EEC (attached + unattached) for (222)Rn and (220)Rn was 29...
August 2016: Radiation and Environmental Biophysics
Venkateswarlu Raavi, Safa Abdul Syed Basheerudeen, Vijayalakshmi Jagannathan, Santosh Joseph, Nabo Kumar Chaudhury, Perumal Venkatachalam
Gamma-H2AX (γ-H2AX) assay is a marker to measure double-strand breaks in the deoxyribonucleic acid. Variables such as age, oxidative stress, temperature, genetic factors and inter-individual variation have been reported to influence the baseline γ-H2AX focus levels. Therefore, knowledge on baseline frequency of γ-H2AX foci in a targeted population would facilitate reliable radiation triage and dose estimation. The objective of the present study was to establish the baseline data using blood samples from healthy volunteers (n = 130) differing in age, occupation and lifestyle as well as from occupationally exposed health workers (n = 20)...
August 2016: Radiation and Environmental Biophysics
Tiina S Tuovinen, Mikko Kolehmainen, Päivi Roivainen, Timo Kumlin, Sari Makkonen, Toini Holopainen, Jukka Juutilainen
In radioecology, transfer of radionuclides from soil to plants is typically described by a concentration ratio (CR), which assumes linearity of transfer with soil concentration. Nonlinear uptake is evidenced in many studies, but it is unclear how it should be taken into account in radioecological modeling. In this study, a conventional CR-based linear model, a nonlinear model derived from observed uptake into plants, and a new simple model based on the observation that nonlinear uptake leads to a practically constant concentration in plant tissues are compared...
August 2016: Radiation and Environmental Biophysics
Daniel G Achel, Antonio M Serafin, John M Akudugu
Large-scale radiological events require immediate and accurate estimates of doses received by victims, and possibly the first responders, to assist in treatment decisions. Although there are numerous efforts worldwide to develop biodosimetric tools to adequately handle triage needs during radiological incidents, such endeavours do not seem to actively involve sub-Saharan Africa which currently has a significant level of nuclear-related activity. To initiate a similar interest in Africa, ex vivo radiation-induced γH2AX expression in peripheral blood lymphocytes from fourteen healthy donors was assessed using flow cytometry...
August 2016: Radiation and Environmental Biophysics
Jing Wang, Lina Yin, Junxiang Zhang, Yaping Zhang, Xuxia Zhang, Defang Ding, Yun Gao, Qiang Li, Honghong Chen
Establishing a rat model suitable for γ-H2AX biodosimeter studies has important implications for dose assessment of internal radionuclide contamination in humans. In this study, γ-H2AX, p-ATM and p-DNA-PKcs foci were enumerated using immunocytofluorescence method, and their protein levels were measured by Western blot in rat blood lymphocytes and granulocytes exposed to γ-rays compared with human blood lymphocytes and granulocytes. It was found that DNA double-strand break repair kinetics and linear dose responses in rat lymphocytes were similar to those observed in the human counterparts...
August 2016: Radiation and Environmental Biophysics
Lydia Laschinsky, Leonhard Karsch, Elisabeth Leßmann, Melanie Oppelt, Jörg Pawelke, Christian Richter, Michael Schürer, Elke Beyreuther
Regarding the long-term goal to develop and establish laser-based particle accelerators for a future radiotherapeutic treatment of cancer, the radiobiological consequences of the characteristic short intense particle pulses with ultra-high peak dose rate, but low repetition rate of laser-driven beams have to be investigated. This work presents in vitro experiments performed at the radiation source ELBE (Electron Linac for beams with high Brilliance and low Emittance). This accelerator delivered 20-MeV electron pulses with ultra-high pulse dose rate of 10(10) Gy/min either at the low pulse frequency analogue to previous cell experiments with laser-driven electrons or at high frequency for minimizing the prolonged dose delivery and to perform comparison irradiation with a quasi-continuous electron beam analogue to a clinically used linear accelerator...
August 2016: Radiation and Environmental Biophysics
B Grosche, M Birschwilks, H Wesch, A Kaul, G van Kaick
It is well known that exposures like those from (226)Ra, (224)Ra and Thorotrast(®) injections increase the risk of neoplasia in bone marrow and liver. The thorium-based radioactive contrast agent Thorotrast(®) was introduced in 1929 and applied worldwide until the 1950s, especially in angiography and arteriography. Due to the extremely long half-life of several hundred years and the life-long retention of the thorium dioxide particles in the human body, patients suffer lifetime internal exposure. The health effects from the incorporated thorium were investigated in a few cohort studies with a German study being the largest among them...
August 2016: Radiation and Environmental Biophysics
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