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Sample records for chronic low-dose x-ray-irradiation

  1. Selective brain responses to acute and chronic low-dose X-ray irradiation in males and females

    International Nuclear Information System (INIS)

    Silasi, Greg; Diaz-Heijtz, Rochellys; Besplug, Jill; Rodriguez-Juarez, Rocio; Titov, Viktor; Kolb, Bryan; Kovalchuk, Olga

    2004-01-01

    Radiation exposure is known to have profound effects on the brain, leading to precursor cell dysfunction and debilitating cognitive declines [Nat. Med. 8 (2002) 955]. Although a plethora of data exist on the effects of high radiation doses, the effects of low-dose irradiation, such as ones received during repetitive diagnostic and therapeutic exposures, are still under-investigated [Am. J. Otolaryngol. 23 (2002) 215; Proc. Natl. Acad. Sci. USA 97 (2000) 889; Curr. Opin. Neurol. 16 (2003) 129]. Furthermore, most studies of the biological effects of ionizing radiation have been performed using a single acute dose, while clinically and environmentally relevant exposures occur predominantly under chronic/repetitive conditions. Here, we have used a mouse model to compare the effects of chronic/repetitive and acute low-dose radiation (LDR) exposure (0.5 Gy) to ionizing radiation on the brain in vivo. We examined the LDR effects on p42/44 MAPK (ERK1/ERK2), CaMKII, and AKT signaling-the interconnected pathways that have been previously shown to be crucial for neuronal survival upon irradiation. We report perturbations in ERK1/2, AKT, and CREB upon acute and chronic/repetitive low-dose exposure in the hippocampus and frontal cortex of mice. These studies were paralleled by the analysis of radiation effects on neurogenesis and cellular proliferation. Repetitive exposure had a much more pronounced effect on cellular signaling and neurogenesis than acute exposure. These results suggest that studies of single acute exposures might be limited in terms of their predictive value. We also present the first evidence of sex differences in radiation-induced signaling in the hippocampus and frontal cortex. We show the role of estrogens in brain radiation responses and discuss the implications of the observed changes

  2. Methylation changes in muscle and liver tissues of male and female mice exposed to acute and chronic low-dose X-ray-irradiation

    International Nuclear Information System (INIS)

    Kovalchuk, Olga; Burke, Paula; Besplug, Jill; Slovack, Mark; Filkowski, Jody; Pogribny, Igor

    2004-01-01

    The biological and genetic effects of chronic low-dose radiation (LDR) exposure and its relationship to carcinogenesis have received a lot of attention in the recent years. For example, radiation-induced genome instability, which is thought to be a precursor of tumorogenesis, was shown to have a transgenerational nature. This indicates a possible involvement of epigenetic mechanisms in LDR-induced genome instability. Genomic DNA methylation is one of the most important epigenetic mechanisms. Existing data on radiation effects on DNA methylation patterns is limited, and no one has specifically studied the effects of the LDR. We report the first study of the effects of whole-body LDR exposure on global genome methylation in muscle and liver tissues of male and female mice. In parallel, we evaluated changes in promoter methylation and expression of the tumor suppressor gene p16 INKa and DNA repair gene O 6 -methylguanine-DNA methyltransferase (MGMT). We observed different patterns of radiation-induced global genome DNA methylation in the liver and muscle of exposed males and females. We also found sex and tissue-specific differences in p16 INKa promoter methylation upon LDR exposure. In male liver tissue, p16 INKa promoter methylation was more pronounced than in female tissue. In contrast, no significant radiation-induced changes in p16 INKa promoter methylation were noted in the muscle tissue of exposed males and females. Radiation also did not significantly affect methylation status of MGMT promoter. We also observed substantial sex differences in acute and chronic radiation-induced expression of p16 INKa and MGMT genes. Another important outcome of our study was the fact that chronic low-dose radiation exposure proved to be a more potent inducer of epigenetic effects than the acute exposure. This supports previous findings that chronic exposure leads to greater genome destabilization than acute exposure

  3. Adaptive response of spermatogenic cell apoptosis selectively induced by low dose X-ray irradiation in mice

    International Nuclear Information System (INIS)

    Liu Guangwei; Dong Lihua; Liu Yang; Lv Zhe; Liu Shuchun; Gong Shouliang

    2003-01-01

    Objective: The adaptive response of spermatogenic cell apoptosis induced by whole-body X-ray irradiation at low doses was studied in mice. Methods: Kunming male mice were irradiated with an inductive dose (D1:75 mGy) and/or a challenging dose (D2:1.0, 2.0 or 3.0 Gy). Different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptotic percentages were analysed using flow cytometry (FCM). Results: When the mice were irradiated with D1 6 h before irradiation with D2, the apoptotic percentages of the spermatogonia and spermatocytes declined rapidly as compared with those in the groups irradiated with D2 only, and those of spermatids and spermatozoa showed no significant changes. When the interval times between D1 and D2 was 3, 6, 12 or 24 h, the apoptotic percentages in spermatogonia and spermatocytes reduced early, significantly and continued for a longer duration after smaller D2(1.0 and 2.0 Gy) irradiation, while the apoptotic percentages did not change after larger D2(3.0 Gy) irradiation. Conclusion: The adaptive response of apoptosis in spermatogonia and spermatocytes could be selectively induced by low dose X-ray irradiation. The adaptive response could be closely related to the D2 dose and interval time between D1 and D2

  4. Inhibitory effects of prior low-dose X-ray irradiation on carbon tetrachloride-induced hepatopathy in acatalasemic mice

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Kataoka, Takahiro; Taguchi, Takehito; Wang, Da-Hong; Mori, Shuji; Hanamoto, Katsumi; Kira, Shohei; Nomura, Takaharu

    2004-01-01

    The catalase activities in blood and organs of the acatalasemic (C3H/AnLCs b Cs b ) mouse of C3H strain are lower than those of the normal (C3H/AnLCs a Cs a ) mouse. We examined the effects of prior low-dose (0.5 Gy) X-ray irradiation, which reduced the oxidative damage under carbon tetrachloride-induced hepatopathy in the acatalasemic or normal mice. The acatalasemic mice showed a significantly lower catalase activity and a significantly higher glutathione peroxidase activity compared with those in the normal mice. Moreover, low-dose irradiation increased the catalase activity in the acatalasemic mouse liver to a level similar to that of the normal mouse liver. Pathological examinations and analyses of blood glutamic oxaloacetic and glutamic pyruvic transaminase activity and lipid peroxide levels showed that carbon tetrachloride induced hepatopathy was inhibited by low-dose irradiation. These findings may indicate that the free radical reaction induced by the lack of catalase and the administration of carbon tetrachloride is more properly neutralized by high glutathione peroxidase activity and low-dose irradiation in the acatalasemic mouse liver. (author)

  5. Effects of low-dose continuously fractionated X-ray irradiation on murine peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Xie Yi; Zhang Hong; Dang Bingrong; Hao Jifang; Guo Hongyun; Wang Xiaohu

    2007-01-01

    For estimating biological risks from low doses continual irradiation, we investigated the effects of exposure to continuously fractionated X-rays on murine immune system. The BALB/c mice were irradiated with 0.07Gy at the first day and 0.08 Gy/d in the following 12 days at a dose rate of 0.2 Gy/min. The peripheral blood lymphocyte cycle and death were determined by flow cytometry at the cumulative doses of 0, 0.07, 0.23, 0.39, 0.55, 0.71, 0.87 and 1.03 Gy respectively. The results showed that the cycle of peripheral blood lymphocyte was arrested in G 0 /G 1 at cumulative doses of 0.07, 0.23, 0.71 and 0.87 Gy, and in G 2 /M at cumulative doses of 0.39 and 1.03 Gy; the percentage of death of peripheral blood lymphocyte was ascended with dose increasing, and reached the death peak at cumulative doses of 0.71 Gy. The results suggested that low doses continual X-rays total-body irradiated could result in changes of cellular cycle and death, and some damages to immunocytes, which accorded to linear square model. (authors)

  6. Effect of low dose X-ray irradiation on apoptosis in spermatogenic cells of mouse testes

    International Nuclear Information System (INIS)

    Liu Guangwei; Liu Shuchun; Lu Zhe; Gong Shouliang

    2003-01-01

    To study the effects of low dose radiation (LDR) with different doses of X-rays on the apoptosis in spermatogenic cells of male Kunming mouse testes. The time-effect and dose-effect of apoptosis in the different stages of spermatogenic cell cycles of mouse testis after LDR with different doses of X-rays were studied with light microscope using the methods of TdT-mediated dUTP nick end labeling (TUNEL) and HE staining. The apoptosis of spermatogenic cells induced by LDR had a remarkable regularity in cell types. When the dose was 0.025 Gy, spermatogonium apoptosis was taken as main. With the dose increase of irradiation (0.025-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic rate of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarcely occurred after irradiation with low dose. The apoptosis of spermatogenic cells induced by LDR has a regular change, which provides a further experimental evidence for the mechanism study of hormesis by LDR

  7. EFFECT OF POLYPHENOLIC COMPLEX FROM WINE ON RATS ANTIOXIDANT ENZYMES ACTIVITY AT X-RAY IRRADIATION LOW DOSES

    Directory of Open Access Journals (Sweden)

    U. V. Datsyuk

    2014-04-01

    Full Text Available It is shown that the consumption of natural polyphenolic complex from grape wine in drinking water in the daily dose 2.5 ± 1.1 mg polyphenols/kg body mass of rats during the 10 day before exposure to radiation leads to increased of superoxide dismutase and gluthathione reductase activities in peripheral blood on 24 and 48 hours after full body X-ray irradiation (30 cGy. The of catalase, gluthathione peroxidase activities and the of the reactive thiobarbituric acid substances content in total lysates of peripheral blood within 72 hours after exposure are comparable to those in control rats. Marked decreased of catalase and superoxide dismutase activities at 24, 48 and 24 hours, respectively, was observed after exposure to ionizing radiation and increased content of lipid peroxidation products in all above mentioned time points. The decreased of superoxide dismutase and gluthathione peroxidase activities in lysates of rats aorta at 48 hour and increased content of the reactive thiobarbituric acid substances during 72 hours after radiation exposure were observed. The consumption of polyphenolic complex from wine did not change the superoxide dismutase and catalase activities in lysates of aorta rats treated with ionizing radiation, whereas gluthathione reductase and gluthathione peroxidase activities was increased during 72 hours after radiation influence. The content of TBA reactive substances was significantly decreased in lysates of aorta rats that were exposed to radiation and polyphenols of grape wine, compared with those of animals that were exposed to radiation alone.

  8. Effects of low dose X-ray irradiation on antigen presentation and IL-12 secretion in human dendritic cells in vitro

    International Nuclear Information System (INIS)

    Yan Peng; Jiang Qisheng; Li Fengsheng; He Rui; Wang Cuilan; Li Xiao

    2012-01-01

    Objective: To explore the effects of low dose X-ray irradiation on the ability of antigen presentation and IL-12 secretion in human dendritic cells that had been cultured for different time in vitro. Methods: The human peripheral blood mononuclear cells (PBMC) were collected and differentiated to dendritic cells (DCs) by rhGM-CSF and rhIL-4 treatment in vitro. The DCs were divided into 3 groups, group A: DCs were cultured for 2 d and then irradiated with 0.05, 0.1, 0.2 and 0.5 Gy X-rays; group B: DCs were cultured for 6 d and then irradiated as above; group C:DCs were cultured without irradiation.At 8 d of cell culture, the DCs were applied to activate T cells and CCK-8 was used to detect MLR (mixed lymphocyte reaction), and the antigen presentation ability of DCs was evaluated. MTT assay was also used to test the cell-killing effect of the activated T-cells on A549 cells. IL-12 in the culture medium of DCs was detected by ELISA. Results: After irradiation with 0.2 and 0.5 Gy X-rays, the antigen presentation ability of DCs was decreased in group A (t=2.79 and 3.71, P<0.05), but significantly increased in group B (t=3.60 and 3.11, P<0.05). The ability of the T cell activation was detected and the proliferation of A549 cells was slightly inhibited by the DCs in group A (t=2.89 and 2.91, P<0.05), but was obviously inhibited by the DCs in group B (t=2.91 and 2.82, P<0.05). Meanwhile,the level of IL-12 was dramatically decreased in group A (t=4.44 and 6.93, P<0.05), but was increased in group B (t=3.51 and 4.12, P<0.05). Conclusions: The abilities of antigen presentation and proliferation inhibition of DCs could be down-regulated by low dose (<0.5 Gy) of X-ray irradiation at the early stage of DCs, but was up-regulated at the late stage of DCs culture. (authors)

  9. DNA–PKcs–SIN1 complexation mediates low-dose X-ray irradiation (LDI)-induced Akt activation and osteoblast differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yong; Fang, Shi-ji [The Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou 215000 (China); Zhu, Li-juan [Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215021 (China); Zhu, Lun-qing, E-mail: xiaodongwangsz@163.com [The Center of Diagnosis and Treatment for Children’s Bone Diseases, The Children’s Hospital Affiliated to Soochow University, Suzhou, Jiangsu 215000 (China); Zhou, Xiao-zhong, E-mail: zhouxz@suda.edu.cn [The Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou 215000 (China)

    2014-10-24

    Highlights: • LDI increases ALP activity, promotes type I collagen (Col I)/Runx2 mRNA expression. • LDI induces DNA–PKcs activation, which is required for osteoblast differentiation. • Akt activation mediates LDI-induced ALP activity and Col I/Runx2 mRNA increase. • DNA–PKcs–SIN1 complexation mediates LDI-induced Akt Ser-473 phosphorylation. • DNA–PKcs–SIN1 complexation is important for osteoblast differentiation. - Abstract: Low-dose irradiation (LDI) induces osteoblast differentiation, however the underlying mechanisms are not fully understood. In this study, we explored the potential role of DNA-dependent protein kinase catalytic subunit (DNA–PKcs)–Akt signaling in LDI-induced osteoblast differentiation. We confirmed that LDI promoted mouse calvarial osteoblast differentiation, which was detected by increased alkaline phosphatase (ALP) activity as well as mRNA expression of type I collagen (Col I) and runt-related transcription factor 2 (Runx2). In mouse osteoblasts, LDI (1 Gy) induced phosphorylation of DNA–PKcs and Akt (mainly at Ser-473). The kinase inhibitors against DNA–PKcs (NU-7026 and NU-7441) or Akt (LY294002, perifosine and MK-2206), as well as partial depletion of DNA–PKcs or Akt1 by targeted-shRNA, dramatically inhibited LDI-induced Akt activation and mouse osteoblast differentiation. Further, siRNA-knockdown of SIN1, a key component of mTOR complex 2 (mTORC2), also inhibited LDI-induced Akt Ser-473 phosphorylation as well as ALP activity increase and Col I/Runx2 expression in mouse osteoblasts. Co-immunoprecipitation (Co-IP) assay results demonstrated that LDI-induced DNA–PKcs–SIN1 complexation, which was inhibited by NU-7441 or SIN1 siRNA-knockdown in mouse osteoblasts. In summary, our data suggest that DNA–PKcs–SIN1 complexation-mediated Akt activation (Ser-473 phosphorylation) is required for mouse osteoblast differentiation.

  10. X-ray irradiation of yeast cells

    Science.gov (United States)

    Masini, Alessandra; Batani, Dimitri; Previdi, Fabio; Conti, Aldo; Pisani, Francesca; Botto, Cesare; Bortolotto, Fulvia; Torsiello, Flavia; Turcu, I. C. Edmond; Allott, Ric M.; Lisi, Nicola; Milani, Marziale; Costato, Michele; Pozzi, Achille; Koenig, Michel

    1997-10-01

    Saccharomyces Cerevisiae yeast cells were irradiated using the soft X-ray laser-plasma source at Rutherford Laboratory. The aim was to produce a selective damage of enzyme metabolic activity at the wall and membrane level (responsible for fermentation) without interfering with respiration (taking place in mitochondria) and with nuclear and DNA activity. The source was calibrated by PIN diodes and X-ray spectrometers. Teflon stripes were chosen as targets for the UV laser, emitting X-rays at about 0.9 keV, characterized by a very large decay exponent in biological matter. X-ray doses to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. After irradiation, the selective damage to metabolic activity at the membrane level was measured by monitoring CO2 production with pressure silicon detectors. Preliminary results gave evidence of pressure reduction for irradiated samples and non-linear response to doses. Also metabolic oscillations were evidenced in cell suspensions and it was shown that X-ray irradiation changed the oscillation frequency.

  11. Radiation effects after low dose chronic long-term exposure

    International Nuclear Information System (INIS)

    Fliedner, T.M.; Friesecke, I.

    1997-01-01

    This document approaches the radiation effects after low dose chronic long-term exposure, presenting examples occurred, the pathophysiologic mechanisms for cell system tolerance in elevated radiation fields, and the diagnostic and therapeutic possibilities

  12. Effect of x-ray irradiated rat fetus mandible

    International Nuclear Information System (INIS)

    Han, Chang Gun; You, Dong Soo

    1978-01-01

    The effect of irradiation of x-ray to developing rat mandible in the gestation stage was focused on the study of mandible development and the side effect of x-ray irradiation. The author studied the effect of x-ray irradiation with the gestated rat and their offsprings. 100 rads, 200 rads, 300 rads and 400 rads of x-ray was irradiated in regular order schematically at the lower left abdomen of gestated rat. 18 1/2 days after conception, their offsprings were sacrificed and examined their developing mandible with histological findings. The results were as followed. 1. In the 100-200 rads irradiated rat offsprings, bony trabeclulation was revealed irregular shape. In combine with this finding, osteoblast and fibroblast were appeared shrunken of their nucleus and location of eccentric position. 2. In the 300-400 rads irradiated rat offsprings, decrease of fibroblast and osteoblast appearance in the periosteum were prominently observed and empty lacunae were frequently appeared in their bone matrix. 3. The advent of osteoclast and resorption of cortical bone were appeared in proportion to increasing of x-ray irradiation.

  13. Effects of ginger extract on testis enzymes of X-ray irradiated mice

    International Nuclear Information System (INIS)

    Zhao Shuhua; Li Jingshun; Wang Chunhua; Pan Qin; Yang Qiong

    2005-01-01

    Objective: To research the effects of extract of ginger on testis enzymes of X-ray irradiated mice. Methods: Mice were treated with three different doses of extract of ginger: high dose (9.3 mL·kg -1 ), middle dose (4.7 mL·kg -1 ), and low dose (2.3 mL·kg -1 ). All mice were irradiated once with 2.0 Gy X-ray. At the same time, the negative group (treated with vegetable oil only) and positive one (irradiated as well as extract of ginger groups after treated with vegetable oil) were set up. The changes of activities of enzymes in testes of mice were observed. Results: After irradiated, in the group of high dose the activity of G-6-PD was decreased but the activity of LDH was increased (P 0.05). In every group, SDH had no significant difference (P>0.05). Conclusion: The proper dose of extract of ginger has significant effects on stabilization of testis enzymes of X-ray irradiated mice. (authors)

  14. The effects of chronic low dose irradiation on drosophila melanogaster

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Moskalev, A.A.; Shaposhnikov, M.V.; Yuraneva, I.N.; Taskaev, A.I.

    2001-01-01

    It was investigated the influence of the chronic gamma-irradiation in the dose rate of 0.17 cGy/h on the rate of genetic variability and on the life-span in the laboratory strains of Drosophila melanogaster with genotypic distinguishes in mobile genetic elements and defects in the DNA repair processes. It is shown that the radiation-induced alteration of the traits under study depends from genotype of investigated strains. In the different strains we have observed an increase as well as a decrease of the mutation rate and life-span. Also it was established that irradiation leads to the frequencies of the GD-sterility and mutability of the snw and h(w+) in the P-M and H-E dysgenic crosses. The obtained results suggest that mobile genetic elements play an important role in the forming of genetic effects in response to low dose irradiation. (author)

  15. Quality control of X-ray irradiator by biological markers

    International Nuclear Information System (INIS)

    Miura, Miwa; Lukmanul Hakkim, F.; Yoshida, Masahiro; Matsuda, Naoki; Morita, Naoko

    2011-01-01

    The exposure of animals or cultured cells to radiation is the essential and common step in experimental researches to elucidate biological effects of radiation. When an X-ray generator is used as a radiation source, physical parameters including dose, dose rate, and the energy spectrum of X-ray play crucial roles in biological outcome. Therefore, those parameters are the important points to be checked in quality control and to be carefully considered in advance to the irradiation to obtain the accurate and reproductive results. Here we measured radiation dose emitted from the X-ray irradiator for research purposes by using clonogenic survival of cultured mammalian cells as a biological marker in parallel with physical dosimetry. The results drawn from both methods exhibited good consistency in the dose distribution on the irradiation stage. Furthermore, the close relationship was observed between cell survival and the photon energy spectrum by using different filter components. These results suggest that biological dosimetry is applicable to quality control of X-ray irradiator in adjunct to physical dosimetry and that it possibly helps better understanding of the optimal irradiating condition by X-ray users in life-science field. (author)

  16. Mucosal pathology of an experimental otitis media with effusion after X-ray irradiation

    International Nuclear Information System (INIS)

    Ohashi, Y.; Nakai, Y.; Ikeoka, H.; Esaki, Y.; Koshimo, H.; Onoyama, Y.

    1987-01-01

    Ten guinea pigs were irradiated with 30 Gy of x-radiation. Five were killed on the eighth day after irradiation, and the remainder were killed at the sixteenth day after irradiation. At the time of death, examination was made of the ciliary activity and the fine structure of the middle ear mucosa. Serous effusion was found in each tympanic cavity of all animals. It was shown also that the guinea pig, when irradiated with 30 Gy of x-radiation, exhibits pathologic abnormalities similar to those in humans with otitis media with effusion: degeneration of cilia or ciliated cells and changes in the vascular system (capillary injury and increased capillary permeability). Functional examinations showed that x-ray irradiation has delayed effects on ciliary activity, and the effects are much greater at the sixteenth day than at the eighth day. We speculate that the accumulation of effusion can be, at least partially, a consequence of ciliary dysfunction. The induction of sterile effusion by the use of x-ray irradiation provides a unique animal model for chronic otitis media with effusion of the serous type

  17. Investigations of X-ray irradiation of marine fish aboard

    International Nuclear Information System (INIS)

    Karnop, G.; Reinacher, E.; Antonacopoulos, N.; Meyer, V.

    1976-01-01

    Studies on X-ray irradiation of ocean perch, cod and coley (at doses of 50-150 krad) are described. The results show that irradiation within this dose range has no significant effect on the shelf-life of fish stored in ice. Although irradiation positively influenced bacteriological and chemical characteristics (e.g. reduction of total aerobic count, and inhibition of decomposition of N-containing compounds), the organoleptically-limited shelf-life of irradiated specimens was similar to that of non-irradiated specimens. Organoleptic changes in irradiated and in non-irradiated samples differed; this is attributed to the abnormal spoilage flora (mainly radiation-resistant Moraxella spp.) in the irradiated samples. (orig./HP) [de

  18. Simulation of X-ray irradiation on human hand

    International Nuclear Information System (INIS)

    Amaya, Fabiola; Montoya, Modesto

    2001-01-01

    Using the Monte Carlo code MCNP we simulate a human hand X-rays irradiation with radiodiagnostic energies to find the better range energy to make radiographs with the lowest dose and an optimal contrast. We calculate bone doses by considering a soft tissue - water - and calcium bone hand, which is irradiated with a million of X-rays photons from a punctual source. These photons are directed inside a conic angle on the hand. Afterwards, we simulate elements which normally compose bones (C, H, O, N, Mg, P, Ca, and S). We estimate bone dose considering: a) bone material (water, calcium and bone tissue); b) bone thickness (0.01; 0.1; 0.5; 1.0; 1.5 and 3.0 cm); and c) source-hand distance (30, 50, 70 and 90 cm). We calculate photon transmission percent through soft tissue and bone tissue and the statistics from the number of photons that reach the radiographic film after passing through soft tissue or bone tissue for our geometric configuration. We found that we can obtain a good image contrast by using X-rays with energies in the range of 20 to 40 keV. (author)

  19. Degradation of organophosphorus compounds by X-ray irradiation

    International Nuclear Information System (INIS)

    Trebse, P.; Arcon, I.

    2002-01-01

    Complete text of publication follows. Our research presented in this contribution aims to elucidate the degradation mechanisms of organophosphate pesticides as organic pollutants by X-ray irradiation. Diazinon, one of the most widely used pesticides in Slovenia, has been chosen as a model compound for the study of radiation induced degradation of organophosphorus pesticides. Recent studies have shown that the degradation of the pesticide at normal conditions (room temperature, exposure to daylight) is strongly enhanced when the pesticide is exposed to UV light (Hg lamp, λ=254 nm, XeCl excimer laser, λ=308 nm). In our study we irradiated the pesticide in aqueous media with a white x-ray beam from a conventional x-ray source. Mo X-ray tube operating at the high voltage of 55 kV and a current of 45 mA was used. The flux of the continuous X-ray beam was stabilized within 1%. Saturated water solution of the pesticide (volume: 4mL, conc. of 40 mg L -1 ) was inserted in 1 cm long lucite cell with 1 mm thick lucite windows. The whole volume of the solution in the cell was exposed to the unfiltered X-ray beam. The dose rate on the sample was about 1 mGy/s. Different irradiation times between 30 min to 120 min were chosen to study the dependence of the pesticide decomposition with the absorbed dose. Solid phase extraction was employed for sample extraction from the solution, and gas chromatography was used for the identification and quantification of the compounds. The results show that the concentration of the pesticide in the solution decreases exponentially with the exposure time, i.e. with the absorbed dose. At irradiation conditions described above, the time constant of the exponential decrease was 74 min

  20. Impact of X-ray irradiation on PMMA thin films

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Saman, E-mail: saman.khan343@gmail.com [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Rafique, Muhammad Shahid [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Anjum, Safia [Physics Department, Lahore College for Woman University, Lahore (Pakistan); Hayat, Asma [Physics Department, University of Engineering and Technology, Lahore (Pakistan); Iqbal, Nida [Faculty of Biomedical Engineering and Health Science, Universiti Teknologi Malaysia (UTM) (Malaysia)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer PMMA thin films were deposited at 300 Degree-Sign C and 500 Degree-Sign C using PLD technique. Black-Right-Pointing-Pointer These films were irradiated with different fluence of laser produced X-rays. Black-Right-Pointing-Pointer Irradiation affects the ordered packing as well as surface morphology of film. Black-Right-Pointing-Pointer Hardness of film decreases up to certain value of X-ray fluence. Black-Right-Pointing-Pointer Absorption in UV-visible range exhibits a non linear behavior. - Abstract: The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300 Degree-Sign C and 500 Degree-Sign C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76 mJ cm{sup -2}. Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV-vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300 Degree-Sign C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500 Degree-Sign C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV-visible region.

  1. Impact of X-ray irradiation on PMMA thin films

    International Nuclear Information System (INIS)

    Iqbal, Saman; Rafique, Muhammad Shahid; Anjum, Safia; Hayat, Asma; Iqbal, Nida

    2012-01-01

    Highlights: ► PMMA thin films were deposited at 300 °C and 500 °C using PLD technique. ► These films were irradiated with different fluence of laser produced X-rays. ► Irradiation affects the ordered packing as well as surface morphology of film. ► Hardness of film decreases up to certain value of X-ray fluence. ► Absorption in UV–visible range exhibits a non linear behavior. - Abstract: The objective of this project is to explore the effect of X-ray irradiation of thin polymeric films deposited at various substrate temperatures. pulsed laser deposition (PLD) technique is used for the deposition of PMMA thin films on glass substrate at 300 °C and 500 °C. These films have been irradiated with various X-rays fluences ranging from 2.56 to 5.76 mJ cm −2 . Characterization of the films (before and after the irradiation) is done with help of X-ray Diffractrometer, Optical Microscope, Vickers hardness tester and UV–vis spectroscopy techniques. From XRD data, it is revealed that ordered packing has been improved for the films deposited at 300 °C. However after irradiation the films exhibited the amorphous behavior regardless of the X-ray fluence. Film deposited at 500 °C shows amorphous structure before and after irradiation. Hardness and particle size of thin film have also increased with the increasing substrate temperature. However, the irradiation has reverse effect i.e. the particle size as well as the hardness has reduced. Irradiation has also enhanced the absorption in the UV–visible region.

  2. Effect of X-ray irradiation on germination of rice and wheat at different temperatures and pH levels of water

    International Nuclear Information System (INIS)

    Rajput, T.B.S.; Singh, Jaswant

    1981-01-01

    An experiment was conducted on the germination of ''Jaya'' rice (Oryza sativa Linn.) and ''Sonalika'' wheat (Triticum aestivum Linn. emend. Thell.) to study the effects of low doses of X-ray irradiation at different temperatures and pH levels of water. The percentage of germination was more at pH 7, and decreased with an increase or decrease in pH level. In most of the cases irradiation delayed the germination and proved to be harmful. But at 20deg C, 4 KR X-ray irradiation promoted the germination of rice by more than 15% at pH levels of 5.5-8.5. But in wheat no significant increase in germination percentage was noted at any combination of the parameters. (auth.)

  3. Linear luminescence for thin plastic scintillator under intense soft X-ray irradiation

    International Nuclear Information System (INIS)

    Ning Jiamin; Jiang Shilun; Xu Rongkun; Guo Cun

    2006-01-01

    The basic principle of soft X-ray power meter is introduced in the paper and the experimental process and the result of thin plastic scintillator linear luminescence under intense soft X-ray irradiation are described. A range of flux density of energy for thin plastic scintillator linear luminescence under intense soft X-ray irradiation is included. The upper limit of the flux density is 1.47 x 10 5 W/cm 2 . (authors)

  4. Changes of surface electron states of InP under soft X-rays irradiation

    International Nuclear Information System (INIS)

    Yang Zhian; Yang Zushen; Jin Tao; Qui Rexi; Cui Mingqi; Liu Fengqin

    1999-01-01

    Changes of surface electronic states of InP under 1 keV X-ray irradiation is studied by X-ray photoelectron spectroscopy (XPS) and ultraviolet ray energy spectroscopy (UPS). The results show that the soft X-ray irradiation has little effect on In atoms but much on P atoms. The authors analysed the mechanism of irradiation and explained the major effect

  5. Injury of the blood-testies barrier after low-dose-rate chronic radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Young Hoon; Bae Min Ji; Lee, Chang Geun; Yang, Kwang Mo; Jur, Kyu; Kim, Jong Sun [Dongnam Institute of Radiological and Medical Science, Busan (Korea, Republic of)

    2014-04-15

    The systemic effect of radiation increases in proportionally with the dose and dose rate. Little is known concerning the relationships between harmful effects and accumulated dose, which is derived from continuous low-dose rate radiation exposure. Recent our studies show that low-dose-rate chronic radiation exposure (3.49 mGy/h) causes adverse effects in the testis at a dose of 2 Gy (6 mGy/h). However, the mechanism of the low-dose-rate 2 Gy irradiation induced testicular injury remains unclear. The present results indicate that low-dose rate chronic radiation might affect the BTB permeability, possibly by decreasing levels of ZO-1, Occludin-1, and NPC-2. Furthermore, our results suggest that there is a risk of male infertility through BTB impairment even with low-dose-rate radiation if exposure is continuous.

  6. Studies on combination effects of peplomycin and x-ray irradiation

    International Nuclear Information System (INIS)

    Munenaga, Yasuichi

    1984-01-01

    In order to study effects and methods of combination of peplomycin (PEP) and x-ray irradiation, inhibitory effects on DNA synthesis were investigated with synchronized cells from the parotid gland of mice treated with isoproterenol (IPR) and inhibitory effects on cell proliferation were investigated with Ehrlich solid tumor cells. PEP had dose-dependent effects on the inhibition of DNA synthesis and on the prolongation of cell cycles in the IPR-treated mouse cells. When 3.0 and 5.0 mg/kg of PEP were combined with 200 rad of x-ray irradiation at the early phase of G 1 , synergistic effects on the inhibition of DNA synthesis were seen. This was most noted in the group with PEP 30 minutes before irradiation. PEP had also dose-dependent inhibitory effects on the proliferation of Ehrlich solid tumor cells. This was increased when x-ray irradiation was combined with PEP. Inhibitory effects on the proliferation of tumor cells were greater when PEP was given before x-ray irradiation than after x-ray irradiation, regardless of the amount. The greatest effect was seen in the group with PEP 30 minutes before irradiation, as well as in the experiment with IPR-treated mouse cells. (Namekawa, K.)

  7. Postharvest quality of dragon fruit (Hylocereus spp.) after x-ray irradiation quarantine treatment

    Science.gov (United States)

    The quality of three dragon fruit clones (Hylocereus sp.) was determined following x-ray irradiation for disinfestation of quarantine pests. Fruit were treated with irradiation doses of 0, 200, 400, 600, or 800 Gy and stored for 12 days at 10 °C. Irradiation did not affect soluble solids content, ti...

  8. Effect of X-ray irradiation on the physical and chemical quality of ...

    African Journals Online (AJOL)

    The use of irradiation as a phytosanitary treatment has expanded in recent years. It plays important roles in developed and developing countries, facilitating international trade in irradiated fresh fruit. To evaluate the potential of X-ray irradiation as a quarantine treatment for America red globe grapes, we investigated the ...

  9. X-ray irradiation on blood products for the purpose of prevention of PT-GVHD

    International Nuclear Information System (INIS)

    Tayama, Tatsuya; Naohara, Tooru; Haneda, Kenji; Juji, Takeo.

    1990-01-01

    X-ray irradiation on blood products is a common method to prevent the risk of inducing PT-GVHD, and has recently become to be used in Japan. We have tried X-ray irradiation on WB, CRC and PC using HITACHI X-ray Irradiation Apparatus MBR1520R, and studied its practical usefulness. In case of irradiation on blood bags as the minimum dose of 1,500 rads, these conditions are thought to be practical: 1) the use of 1.0 mm Al filter, 2) the distance of 550 nm from X-ray source, and 3) irradiation on 4 bags at the same time. But, it has also been noticed that total doses and qualities of X-ray absorbed into blood were different between upper and lower side of the bag. Bloods on upper side absorbed much doses and a wide range of X-ray, on the other hand, bloods on lower side absorbed less doses and hard X-ray. In these conditions, irradiated lymphocytes showed a complete inhibition of thymidine uptake in MLC test, still had 15% of activity in PHA stimulation. The qualities of other blood components have not changed before and after irradiation. X-ray irradiation is useful in a routine work of blood center, but problems of proper doses and a uniformity of irradiation are remained to be solved. (author)

  10. Effects of x-ray irradiation on mast cells and mastocalcergy in the connective tissue

    Energy Technology Data Exchange (ETDEWEB)

    Song, H. Y.; Rhee, S. J.; Son, M. H.; Choi, K. C. [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

    1982-09-15

    Experiments were performed to observe the influence of x-ray irradiation on mast cells and mastocalcergy in rats. Animals were irradiated single dose of x-ray. X-ray irradiation was applied to the whole body in doses either 100 rads or 150 rads (Cobalt-60 Teletherapy Unit). One day after irradiation the rats were injected lead acetate intravenously, followed by injection of compound 48/80 in the back subcutaneously. Animals were killed by decapitation at intervals, 1 hour, 5 hours, 1 day and 6 day after subcutaneous injection. Specimens of the abdominal and back skin were fixed in alcohol formol solution and stained with the following methods; H-E for observation of pathological changes of tissues, toluidine blue for demonstration of mast cells, von Kossa-azure A for demonstration of carbonate and phosphate, and chloranilic acid for demonstration of calcium. The following conclusions were obtained. Calciphylatic wheals are large size in the control group, medium size in 100 rads irradiation group and small size in 150 rads irradiation group. In x-ray irradiation groups the number of mast cells decreases more in the 150 rads than in the 100 rads irradiation. In the 100 rads x-ray irradiation group, histochemical study of the injection sites showed that calcium impregnated to mast cell granules and connective tissue fibers in 1 days after subcutaneous injection. The morphogenesis of this calcinosis was the same in the rat of 5 hour after subcutaneous injection of the control group. Whereas, 1 day after subcutaneous injection in 150 rads x-ray irradiation group calcium deposited more slightly than other groups.

  11. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    Science.gov (United States)

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  12. Alteration of cytokine profiles in mice exposed to chronic low-dose ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Suk Chul [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Lee, Kyung-Mi [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kang, Yu Mi [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Kwanghee [Global Research Lab, BAERI Institute, Department of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul 136-705 (Korea, Republic of); Kim, Cha Soon; Yang, Kwang Hee; Jin, Young-Woo [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of); Kim, Chong Soon [Department of Nuclear Medicine, Haeundae Paik Hospital, Inje University, Busan 612-030 (Korea, Republic of); Kim, Hee Sun, E-mail: hskimdvm@khnp.co.kr [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., 388-1, Ssangmun-dong, Dobong-gu, Seoul 132-703 (Korea, Republic of)

    2010-07-09

    While a high-dose of ionizing radiation is generally harmful and causes damage to living organisms, a low-dose of radiation has been shown to be beneficial in a variety of animal models. To understand the basis for the effect of low-dose radiation in vivo, we examined the cellular and immunological changes evoked in mice exposed to low-dose radiation at very low (0.7 mGy/h) and low (3.95 mGy/h) dose rate for the total dose of 0.2 and 2 Gy, respectively. Mice exposed to low-dose radiation, either at very low- or low-dose rate, demonstrated normal range of body weight and complete blood counts. Likewise, the number and percentage of peripheral lymphocyte populations, CD4{sup +} T, CD8{sup +} T, B, or NK cells, stayed unchanged following irradiation. Nonetheless, the sera from these mice exhibited elevated levels of IL-3, IL-4, leptin, MCP-1, MCP-5, MIP-1{alpha}, thrombopoietin, and VEGF along with slight reduction of IL-12p70, IL-13, IL-17, and IFN-{gamma}. This pattern of cytokine release suggests the stimulation of innate immunity facilitating myeloid differentiation and activation while suppressing pro-inflammatory responses and promoting differentiation of naive T cells into T-helper 2, not T-helper 1, types. Collectively, our data highlight the subtle changes of cytokine milieu by chronic low-dose {gamma}-radiation, which may be associated with the functional benefits observed in various experimental models.

  13. Cytogenetic investigations of persons exposed to professional chronic low-dose irradiation

    International Nuclear Information System (INIS)

    Rangelov, V.; Mitev, L.; Petrunov, P.; Vesselinova, L.

    2005-01-01

    The problem of long term influence of low-doses occupational irradiation is connected with the real assessment of their consequences. The current cytogenetic investigations were done on persons working under occupational chronic external partial irradiation. Accumulated doses of external irradiation are surveyed. Data give ground for suggestion about the relationship between accumulated dose and chromosomal aberrations. The additional damage factors (diagnostic investigations, chemical substances, tobacco addict) have done the more significant influence upon aberrations appearance increasing

  14. Chronic low dose radiation exposure and oxidative stress in radiation workers

    International Nuclear Information System (INIS)

    Ali, S.S.; Bhatt, M.B.; Kulkarni, MM.; Rajan, R.; Singh, B.B.; Venkataraman, G.

    1996-01-01

    Free radicals have been implicated in the pathogenesis of several human diseases. In this study free radical stress due to low dose chronic radiation exposures of radiation workers was examined as a possible atherogenic risk factor. Data on lipid profiles, lipid peroxidation and reduced glutathione content in blood indicated an absence of correlation with radiation doses up to 125 mSv. (author). 13 refs., 1 fig

  15. Metabolomics identifies a biological response to chronic low-dose natural uranium contamination in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Eric; Banzet, Nathalie; Defoort, Catherine; Bott, Romain; Dublineau, Isabelle; Aigueperse, Jocelyne; Gourmelon, Patrick; Martin, Jean-Charles; Souidi, Maâmar

    2013-01-01

    Because uranium is a natural element present in the earth's crust, the population may be chronically exposed to low doses of it through drinking water. Additionally, the military and civil uses of uranium can also lead to environmental dispersion that can result in high or low doses of acute or chronic exposure. Recent experimental data suggest this might lead to relatively innocuous biological reactions. The aim of this study was to assess the biological changes in rats caused by ingestion of natural uranium in drinking water with a mean daily intake of 2.7 mg/kg for 9 months and to identify potential biomarkers related to such a contamination. Subsequently, we observed no pathology and standard clinical tests were unable to distinguish between treated and untreated animals. Conversely, LC-MS metabolomics identified urine as an appropriate biofluid for discriminating the experimental groups. Of the 1,376 features detected in urine, the most discriminant were metabolites involved in tryptophan, nicotinate, and nicotinamide metabolic pathways. In particular, N -methylnicotinamide, which was found at a level seven times higher in untreated than in contaminated rats, had the greatest discriminating power. These novel results establish a proof of principle for using metabolomics to address chronic low-dose uranium contamination. They open interesting perspectives for understanding the underlying biological mechanisms and designing a diagnostic test of exposure.

  16. Late effects of chronic low dose-rate γ-rays irradiation on mice

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Sasagawa, Sumiko; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Sato, Fumiaki

    2002-01-01

    To evaluate late biological effects of chronic low dose-rate radiation, we are conducting two experiments. Experiment 1 - Late effects of chronic low dose-rate g-rays irradiation on SPF mice, using life-span and pathological changes as parameters. Continuous irradiation with g-rays for 400 days was performed using 137 Cs γ-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8,000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until they died a natural death. As of 2002 March 31, 3,999 of the total 4,000 mice have died. Preliminary analyses of data show that 20 mGy/day suggested a shortened life span in both sexes. Partial results show that the most common lethal neoplasms in the pooled data of non-irradiated control and irradiated male mice, in order of frequency, were neoplasms of the lymphohematopoietic system, liver, and lung. In female mice, neoplasms of the lymphohematopoietic system, soft tissue, and endocrine system were common. Experiment 2 - Effects on the progeny of chronic low dose-rate g-ray irradiated SPF mice: pilot study, was started in 1999 and is currently in progress. (author)

  17. The effects of chronic, low doses of Ra-226 on cultured fish and human cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaopei; Seymour, Colin; Mothersill, Carmel, E-mail: mothers@mcmaster.ca

    2016-07-15

    Purpose: To determine the chronic low-dose radiation effects caused by α-particle radiation from {sup 226}Ra over multiple cell generations in CHSE/F fish cells and HaCaT human cells. Methods: CHSE/F cells and HaCaT cells were cultured in medium containing {sup 226}Ra to deliver the chronic low-dose α-particle radiation. Clonogenic assay was used to test the clonogenic survival fractions of cells with or without being exposed to radiation from {sup 226}Ra. Results: The chronic low-dose radiation from {sup 226}Ra does have effects on the clonogenic survival of CHSE/F cells and HaCaT cells. When CHSE/F cells were cultured in {sup 226}Ra-medium over 9 passages for about 134 days, the clonogenic surviving fractions for cells irradiated at dose rates ranging from 0.00066 to 0.66 mGy/d were significantly lower than that of cells sham irradiated. For HaCaT cells grown in medium containing the same range of {sup 226}Ra activity, the clonogenic surviving fraction decreased at first and reached the lowest value at about 42 days (8 passages). After that, the clonogenic survival began to increase, and was significantly higher than that of control cells by the end of the experimental period. Conclusion: The chronic, low-dose high LET radiation from {sup 226}Ra can influence the clonogenic survival of irradiated cells. CHSE/F cells were sensitized by the radiation, and HaCaT cells were initially sensitized but later appeared to be adapted. The results could have implications for determining risk from chronic versus acute exposures to radium. - Highlights: • Cells were exposed to chronic low-dose α-radiation from {sup 226}Ra in medium with {sup 226}Ra. • The clonogenic survival of CHSE/F cells decreased when exposed to {sup 226}Ra for 134 days. • The clonogenic survival of HaCaT cells decreased at first and then increased. • The doubling time of both cells were not affected by this kind of radiation.

  18. SOFT X-RAY IRRADIATION OF SILICATES: IMPLICATIONS FOR DUST EVOLUTION IN PROTOPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Ciaravella, A.; Cecchi-Pestellini, C.; Jiménez-Escobar, A. [INAF—Osservatorio Astronomico di Palermo, P.za Parlamento 1, I-90134 Palermo (Italy); Chen, Y.-J.; Huang, C.-H. [Department of Physics, National Central University, Jhongli City, Taoyuan County 32054, Taiwan (China); Muñoz Caro, G. M. [Centro de Astrobiología (INTA-CSIC), Carretera de Ajalvir, km 4, Torrejón de Ardoz, E-28850 Madrid (Spain); Venezia, A. M., E-mail: aciaravella@astropa.unipa.it [ISMN—CNR, Via Ugo La Malfa 153, I-90146 Palermo (Italy)

    2016-09-01

    The processing of energetic photons on bare silicate grains was simulated experimentally on silicate films submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted sol–gel technique. Its chemical composition reflects the Mg{sub 2}SiO{sub 4} stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray-irradiated protoplanetary disks.

  19. Aqueous gold nanosols stabilized by electrostatic protection generated by X-ray irradiation assisted radical reduction

    International Nuclear Information System (INIS)

    Wang, C.-H.; Hua, Tzu-En; Chien, C.-C.; Yu, Y.-L.; Yang, T.-Y.; Liu, C.-J.; Leng, W.-H.; Hwu, Y.; Yang, Y.-C.; Kim, Chong-Cook; Je, Jung-Ho; Chen, C.-H.; Lin, H.-M.; Margaritondo, G.

    2007-01-01

    Reductant, stabilizer-free colloidal gold solutions were fabricated by a new room-temperature synchrotron X-ray irradiation method. The influence of process parameters such as the pH value and the exposure time on the structure of gold nanoparticles was investigated. The mechanisms underlying the X-ray-triggered reduction of gold ions and the formation of gold clusters are discussed in detail. The X-ray irradiation derived highly concentrated gold nanoparticles are readily to be re-dispersed and possess suitable colloidal stability within cellular environment. The characterization included a study of the possible cytotoxicity for the EMT-6 tumor cell line: the negative results indicate that the gold clusters produced with our approach are biocompatible

  20. Elimination of radical on the x-ray irradiated hydroxyapatite compounds

    International Nuclear Information System (INIS)

    Ohta, M.; Yasuda, M.; Miyazawa, C.; Okamura, H.; Suzuki, Y.

    2002-01-01

    We investigate the elimination of radical produced in a human tooth and synthetic calcium-deficient hydroxyapatite compounds after X-ray irradiation. Used samples were enamel and dentine of a human tooth and synthetic calcium-deficient hydroxyapatite (DAp), and stoichiometric hydroxyapatite (HAp). The ESR signal intensities at nearly g = 2 in the samples after X-ray irradiation were proportional to the absorbed dose in the range from 6 to 39 Gy. And these ESR signal intensities of the samples soaked in various ion containing fluids decreased with soaking time. Especially, the decrease in these ESR signal intensities was remarkably large in the samples soaked in Na 2 HPO 4 aqueous solution. This fact suggests that the surface layer of the samples easily dissolves in ion containing fluids

  1. Effect of x-ray irradiation ovary on interleukin 2 secretion in rats

    International Nuclear Information System (INIS)

    Huang Hui; Lin Yunlu; Zhang Haijun; Wang Hongfu

    1993-01-01

    The effects of interleukin 2 (IL-2) secretion were studied in a rat model by means of x-ray irradiated ovary. It was found that the reduction of estradiol (E 2 )in serum could promote lymphocyte blastogenesis and IL-2 secretion. There was also found a correlation between IL-2 production and the level of E 2 in serum (r = -0.952, P 2 might be associated with a decreased nonspecific immunity

  2. Ac-electrical conductivity of poly(propylene) before and after X-ray irradiation

    International Nuclear Information System (INIS)

    Gaafar, M.

    2001-01-01

    Study on the ac-electrical conductivity of poly(propylene), before and after X-ray irradiation within the temperature range 300-360 K are reported. The measurements have been performed in a wide range of frequencies (from 0 to 10 5 Hz) and under the effect of different X-ray irradiation doses (from 0 to 15 Gy). Cole-Cole diagrams have been used to show the frequency dependence of the complex impedance at different temperatures. The results exhibit semicircles which are consistent with existing equivalent circuit model. Analysis of the results reveal semiconducting features based mainly on a hopping mechanism. The study shows a pronounced effect of X-ray irradiation on the electrical conductivity at zero frequency σ DC . At the early stage of irradiation, σ DC increased as a result of free radical formation. As the irradiation progressed, it decreased as a result of crosslinking, then it increased again due to irradiation induced degradation, which motivates the generation of mobile free radicals. The study shows that this polymer is one among other polymers which its electrical conductivity is modified by irradiation

  3. Ac-electrical conductivity of poly(propylene) before and after X-ray irradiation

    Science.gov (United States)

    Gaafar, M.

    2001-05-01

    Study on the ac-electrical conductivity of poly(propylene), before and after X-ray irradiation within the temperature range 300-360 K are reported. The measurements have been performed in a wide range of frequencies (from 0 to 10 5 Hz) and under the effect of different X-ray irradiation doses (from 0 to 15 Gy). Cole-Cole diagrams have been used to show the frequency dependence of the complex impedance at different temperatures. The results exhibit semicircles which are consistent with existing equivalent circuit model. Analysis of the results reveal semiconducting features based mainly on a hopping mechanism. The study shows a pronounced effect of X-ray irradiation on the electrical conductivity at zero frequency σDC. At the early stage of irradiation, σDC increased as a result of free radical formation. As the irradiation progressed, it decreased as a result of crosslinking, then it increased again due to irradiation induced degradation, which motivates the generation of mobile free radicals. The study shows that this polymer is one among other polymers which its electrical conductivity is modified by irradiation.

  4. Study on the inactivation of intracellular enzyme molecules by X-ray irradiation

    International Nuclear Information System (INIS)

    Lee, S.B.

    1977-01-01

    Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzyme molecules were irradiated by the X-ray radiation under the condition of 65 kV, 1 Amp under the atmosphere of nitrogen gases and by 4 0 C. Thereby, irradiation doses were 580 KR/min(error: +-3%). After irradiation, the cell homogentes were prepared through liquid air techniques. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were 6.5x10 6 and 5.0x10 6 R respectively. These results showed one side that the inactivation process of the intracellular enzyme molecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzyme molecules was discussed. (author)

  5. Low-temperature crystallization of amorphous silicon and amorphous germanium by soft X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Heya, Akira, E-mail: heya@eng.u-hyogo.ac.jp [Department of Materials Science and Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671–2280 (Japan); Kanda, Kazuhiro [Laboratory of Advanced Science and Technology for Industry (LASTI), University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678–1205 (Japan); Toko, Kaoru; Sadoh, Taizoh [Department of Electronics, Kyushu University, 744 Nishi-ku, Motooka, Fukuoka 819–0395 (Japan); Amano, Sho [Laboratory of Advanced Science and Technology for Industry (LASTI), University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678–1205 (Japan); Matsuo, Naoto [Department of Materials Science and Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671–2280 (Japan); Miyamoto, Shuji [Laboratory of Advanced Science and Technology for Industry (LASTI), University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678–1205 (Japan); Miyao, Masanobu [Department of Electronics, Kyushu University, 744 Nishi-ku, Motooka, Fukuoka 819–0395 (Japan); Mochizuki, Takayasu [Laboratory of Advanced Science and Technology for Industry (LASTI), University of Hyogo, 3-2-1 Koto, Kamigori, Hyogo 678–1205 (Japan)

    2013-05-01

    The low-temperature-crystallization effects of soft X-ray irradiation on the structural properties of amorphous Si and amorphous Ge films were investigated. From the differences in crystallization between Si and Ge, it was found that the effects of soft X-ray irradiation on the crystallization strongly depended on the energy band gap and energy level. The crystallization temperatures of the amorphous Si and amorphous Ge films decreased from 953 K to 853 K and 773 K to 663 K, respectively. The decrease in crystallization temperature was also related to atoms transitioning into a quasi-nucleic phase in the films. The ratio of electron excitation and migration effects to thermal effects was controlled using the storage-ring current (photon flux density). Therefore, we believe that low-temperature crystallization can be realized by controlling atomic migration through electron excitation. - Highlights: • This work investigates the crystallization mechanism for soft X-ray irradiation. • The soft X-ray crystallization depended on the energy band gap and energy level. • The decrease in the crystallization temperature for Si and Ge films was 100 K. • This decrement was related to atoms transitioning into a quasi-nucleic phase.

  6. A new fully integrated X-ray irradiator system for dosimetric research

    International Nuclear Information System (INIS)

    Richter, D.; Mittelstraß, D.; Kreutzer, S.; Pintaske, R.; Dornich, K.; Fuchs, M.

    2016-01-01

    A fully housed X-ray irradiator was developed for use within lexsyg or Magnettech desktop equipment. The importance of hardening of the low energy photon radiation is discussed, its performance and feasibility is empirically shown and sustained by basic numerical simulations. Results of the latter for various materials are given for different X-ray source settings in order to provide estimates on the required setup for the irradiation of different geometries and materials. A Si-photodiode provides real-time monitoring of the X-ray-irradiator designed for use in dosimetric dating and other dosimetric application where irradiation of small samples or dosemeters is required. - Highlights: • Bench top X-ray irradiator provides variable dose-rates. • Simulation of low energy photon irradiation and hardening of X-ray. • Al-hardening for the irradiation of H_2O, BeO, Al_2O_3, quartz, feldspars and zircon. • Dosimetric dating equipment for luminescence and ESR.

  7. Adaptation dynamics of laboratory populations of Drosophila Melanogaster to low dose chronic ionizing irradiation

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Yushkova, E.A.

    2008-01-01

    In genetically non-uniform populations D. melanogaster in conditions of a chronic irradiation in a doze 10-11 about sGy/generation dynamics parameters of populations was investigated. It is established, that number of individuals in irradiated populations is lower, than in control. It is revealed, that viability of populations undergone to a chronic irradiation depends on their genotype. The gradual increase in fruitfulness, viability of individuals and decrease in a level of lethal mutations in a number of generations after of an irradiation in low doses is caused by adaptable opportunities of populations. (authors)

  8. MeV single-ion beam irradiation of mammalian cells using the Surrey vertical nanobeam, compared with broad proton beam and X-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Jeynes, J.C.G.; Merchant, M.J.; Kirkby, K.; Kirkby, N. [Surrey Ion Beam Center, Faculty of Engineering and Physical Science, University of Surrey, Guildford Surrey, GU2 7XH (United Kingdom); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: •Recently completed nanobeam at the Surrey Ion Beam Centre was used. •3.8-MeV single and broad proton beams irradiated Chinese hamster cells. •Cell survival curves were measured and compared with 300-kV X-ray irradiation. •Single ion irradiation had a lower survival part at ultra-low dose. •It implies hypersensitivity, bystander effect and cell cycle phase of cell death. -- Abstract: As a part of a systematic study on mechanisms involved in physical cancer therapies, this work investigated response of mammalian cells to ultra-low-dose ion beam irradiation. The ion beam irradiation was performed using the recently completed nanobeam facility at the Surrey Ion Beam Centre. A scanning focused vertical ion nano-beam was applied to irradiate Chinese hamster V79 cells. The V79 cells were irradiated in two different beam modes, namely, focused single ion beam and defocused scanning broad ion beam of 3.8-MeV protons. The single ion beam was capable of irradiating a single cell with a precisely controlled number of the ions to extremely low doses. After irradiation and cell incubation, the number of surviving colonies as a function of the number of the irradiating ions was measured for the cell survival fraction curve. A lower survival for the single ion beam irradiation than that of the broad beam case implied the hypersensitivity and bystander effect. The ion-beam-induced cell survival curves were compared with that from 300-kV X-ray irradiation. Theoretical studies indicated that the cell death in single ion irradiation mainly occurred in the cell cycle phases of cell division and intervals between the cell division and the DNA replication. The success in the experiment demonstrated the Surrey vertical nanobeam successfully completed.

  9. Effect of a low-dose x-ray irradiation on the development and differentiation of the cerebral cortex, (15)

    International Nuclear Information System (INIS)

    Hayashi, Yasushi; Hoshino, Kiyoshi; Hayasaka, Shizuka; Kameyama, Yoshiro

    1981-01-01

    Mice of 17 day's gestation received x-rays of 10 R, 25 R, or 100 R, and those of 13 or 15 day's gestation received 10 R in a single exposure. These irradiated fetuses were examined for the weight of the brain, thickness of the cerebral cortex, density of the cortical cells and branching of the pyramidal cells in the fifth layer of the cortex 12 weeks after birth. Decrease in the thickness of the cortex was observed in the mice which received 100 R at 17 day's gestation. A decrease in the branching index of the pyramidal cells was found in the mice which received 100 R. Although a decreasing tendency of the branching index was also recognized in those which received 10 R at 13 days of gestation, showing no statistically significant difference. (Ueda, J.)

  10. Gold nanoparticles: BSA (Bovine Serum Albumin) coating and X-ray irradiation produce variable-spectrum photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kuo-Hao [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China); Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Lai, Sheng-Feng [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Yan-Cheng; Chou, Wu-Ching [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China); Ong, Edwin B.L. [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Tan, Hui-Ru [Institute of Materials Research and Engineering, 3 Research Link, 117602 (Singapore); Tok, Eng Soon [Physics Department, National University of Singapore, 117542 (Singapore); Yang, C.S. [Center for Nanomedicine, National Health Research Institutes, Miaoli 350, Taiwan (China); Margaritondo, G. [Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Hwu, Y., E-mail: phhwu@sinica.edu.tw [Institute of Physics, Academia Sinica, Taipei 115, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung 202, Taiwan (China)

    2015-01-15

    We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emission bands, one due to BSA and the other related to gold. The emission properties did not change with time over a period of several months. - Highlights: • Gold nanoparticles (Au NPs) coated with Bovine Serum Albumin (BSA) are synthesized by x-ray irradiation. • BSA coated AuNPs with ∼1 nm size show strong photoluminescence in red by UV excitation. • The blue photoluminescence of BSA increase with x-ray irradiation. • Increase x-ray irradiation time during the synthesis shift the color of the colloid from red to blue.

  11. Gold nanoparticles: BSA (Bovine Serum Albumin) coating and X-ray irradiation produce variable-spectrum photoluminescence

    International Nuclear Information System (INIS)

    Lee, Kuo-Hao; Lai, Sheng-Feng; Lin, Yan-Cheng; Chou, Wu-Ching; Ong, Edwin B.L.; Tan, Hui-Ru; Tok, Eng Soon; Yang, C.S.; Margaritondo, G.; Hwu, Y.

    2015-01-01

    We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emission bands, one due to BSA and the other related to gold. The emission properties did not change with time over a period of several months. - Highlights: • Gold nanoparticles (Au NPs) coated with Bovine Serum Albumin (BSA) are synthesized by x-ray irradiation. • BSA coated AuNPs with ∼1 nm size show strong photoluminescence in red by UV excitation. • The blue photoluminescence of BSA increase with x-ray irradiation. • Increase x-ray irradiation time during the synthesis shift the color of the colloid from red to blue

  12. Genetic efficiency of low-dose chronic irradiation in mammals and fish

    International Nuclear Information System (INIS)

    Goncharova, R.; Ryabokon, N.; Smolich, I.; Slukvin, A.

    2001-01-01

    The problem of biological effects of low-dose chronic irradiation is central radiobiological problem and seems to be very important for human monitoring and risk assessment Since 1986 we are engaged in studying genetic effects of low-dose chronic irradiation in natural populations of small mammals (bank vole - Clethrioiiomys glareolus) inhabiting radiocontaminated monitoring sites, in laboratory hybrid mice CBA*C57BI/6 j exposed to chronic irradiation at radiocontaminated sites, as well as in pond carp (Cyprinus carpio) reared in fish farms in areas contaminated due to the Chernobyl accident. The mean ground depositions in monitoring sites were 8-2330 kBq/m 2 and the mean bottom depositions in ponds were 52-3235 Bq/kg for Cs 137. We used conventional cytogenetics and genetics tests [1-3] and the following approaches in studying on genetic effects of low-dose chronic irradiation: Radiation exposures from external γ- and internal α, β, γ-irradiation from incorporated radionuclides were estimated for each specimen tested. Regression analysis of dose-effect relationships based on comparison of individual genetic end-points with individual absorbed doses was carried out We observed statistically significant changes in the frequencies of genetic end-points, which have been studied in somatic and germ cells, as well as in embryos of irradiated mammals and fish. So, the frequencies of chromosome aberrations in bank vole populations had up to 7-fold increase in comparison with background and pre-accident levels. It is of great importance to emphasize high radio-sensitivity of fertilized eggs (zygotes) and pond carp, embryos produced by chronically irradiated parents. Regression analysis allowed to reveal dependence of the studied parameters' frequencies on radiation exposure namely on the concentrations of basic dose forming radionuclides, absorbed dose rate and whole body absorbed dose. In most cases, dose-effect relationships were better approximated by non

  13. Cytogenetic damage at low doses and the problem of bioindication of chronic low level radiation exposure

    International Nuclear Information System (INIS)

    Geras'kin, S.A.; Dikarev, V.G.; Nesterov, E.B.; Vasiliev, D.V.; Dikareva, N.S.

    2000-01-01

    The analysis undertaken by us of the experimentally observed cellular responses to low dose irradiation has shown that the relationship between the yield of induced cytogenetic damage and radiation dose within low dose range is non-linear and universal in character. Because of the relationship between the yield of cytogenetic damage and dose within low dose range is non-linear, the aberration frequency cannot be used in biological dosimetry in the most important in terms of practical application case. The cytogenetic damage frequency cannot be used in biological dosimetry also because of the probability of synergistic and antagonistic interaction effects of the different nature factors simultaneously acting on test-object in real conditions is high within low dose (concentration) range. In our experimental study of the regularities in the yield of structural mutations in conditions of combined influence of ionizing radiation, heavy metals and pesticides it was found that synergistic and antagonistic effects are mainly induced in conditions of combined action of low exposure injuring agents. Experiments on agricultural plants were carried out in 1986-1989 at the 30-km zone around Chernobyl NPP. It was shown that chronic low dose exposure could cause an inheritable destabilization of genetic structures expressing in increase of cytogenetic damage and yield karyotypic variability in offspring's of irradiated organisms. Obviously exactly this circumstance is the reason of the phenomenon found in our researches of significant time delay of cytogenetic damage reduction rate from radioactive pollution reduction rate from time past from the accident moment. Research of cytogenetic damage of reproductive (seeds) and vegetative (needles) plant organs of the Pinus sylvestris tree micropopulations growing in contrast by radioactive pollution level sites of the 30-km ChNPP zone and also in the vicinity of the industrial plant > for processing and temporary storage of

  14. Destroying the photoelectret in Bi12SiO20 by X-ray irradiation

    International Nuclear Information System (INIS)

    Vavrek, A. F.; Khristova, K. K.

    1987-01-01

    The destroying of the classical photoelectret state (PES) in bismuth silicon oxide (BSO) monocrystals during X-ray irradiation is investigated and the reciprocity law (RL) is examined. The sample is irradiated by nonfiltered X-rays with continuous spectrum and maximum energy of the photons 70 keV. The polaryzing voltage used is 85 V. The dependence of the destroyed PE charge on the time of X-ray irradiation of the sample with equal X-ray exposure in each point shows that the exposure rates higher than a certain 'critical' value cause a larger destroyed charge that is RL during X-ray irradiation. The 'critical' value is about 3x10 -5 A/kg. The dependence of the destroyed photoelectric (PE) charge on the irradiation time generally shows that the destroyed PE charge increases with the increase of the X-ray exposure. After some time the distruction of the charge is terminated and the sample seems to lose its X-ray sensitivity although a considerable PE charge (30-40% of the initial one) remains in it. At higher exposure rates (above the critical one for the RL) the maxmimum destroyed charge is smaller. According to the dependencies of the linear coefficients of X-ray attenuation in the investigated energy range the photoelectric absorption is dominating. The radiation is absorbed only in the near-surface region. Part of the sample remains nonexited and the PE charge which has been initially barrier distributed is destroyed as a result of the redistribution of the charges in the excitation region only. At sufficiently long irradiation time this redistribution is terminated, notwithstanding the fact that out of the excitation region the sample still remains polarized. The maximum destroyed PE charge during nonhomogeneous excitation under nonquasi-stationary conditions is smaller at higher exposure rates because of the lower values of the diffusion and drift length

  15. Central blood circulation in children at chronic combined low dose radiation and chemical action

    International Nuclear Information System (INIS)

    Arinchin, A.N.

    2000-01-01

    The state of central blood circulation and its hormonal regulation were studied in 1465 children living permanently under chronic low dose radiation and chemical action. Basic group consisted of 1093 children (579 boys and 514 girls) . 372 children (115 boys and 227 girls permanently living on 'clean' areas) were investigated in control group. Average age was 10,8 years old in basic group and 10,4 years old in the control group. Such parameters as arterial pressure, level of lead in blood and urine, adrenaline, noradrenaline and dophamine content in urine, thyroxine, iodothyronine, prostaglandins and cyclic AMP content in the blood serum has been controlled. Hypotensive states were determined to prevail in children living permanently under chronic low dose radiation and chemical action. The main pathogenic mechanism of this defeat is consider to be a reduction of the sympathoadrenal system activity combined with a decreasing of the thyroid system activity and of cyclic AMP level as well as predominance of prostaglandin depressive activity

  16. The effect of cepharanthin on the hemopoietic suppression by X-ray irradiation

    International Nuclear Information System (INIS)

    Mori, Masaharu; Kawasaki, Seiji; Sacho, Masanori; Awai, Michiyasu; Ono, Minoru; Sadahira, Yoshito.

    1989-01-01

    The effects of cepharanthin on the suppression of hemopoiesis by X-ray irradiation were studied. A whole body X-irradiation (3 Gy) induced decrease of leucocyte count, nucleated cell count of bone marrow, myeloid stem cell count (CFU-C), and spleen weight. Oral administration of cepharanthin (25 mg/kg BW or 50 mg/kg BW) tended to decrease these damage on hemopoiesis, and increased spleen weight on 5th day after irradiation. Histological examinations revealed that the administration of cepharanthin accerelated the hemopoietic recovery in the red pulp of spleen. (author)

  17. Indirect (x-ray) irradiation of encapsulated microtargets in the Iskra-5 facility

    International Nuclear Information System (INIS)

    Abzaev, F.M.; Bel'kov, S.A.; Bessarab, A.V.; Bondarenko, S.V.; Gaidash, V.A.; Garanin, S.G.; Dolgoleva, G.V.; Zhidkov, N.V.; Izgorodin, V.M.; Kirillov, G.A.; Kochemasov, G.G.; Litvin, D.N.; Martynenko, S.P.; Murugov, V.M.; Mkhitar'yan, L.S.; Pinegin, A.V.; Petrov, S.I.; Senik, A.V.; Suslov, N.A.; Bushuev, V.S.

    1998-01-01

    Experiments on the indirect (x-ray) irradiation of high-aspect-ratio capsules (with a diameter-to-thickness ratio ≅900) filled with DT gas are performed on the Iskra-5 laser facility. It is shown that all the characteristics measured (neutron yield, ion temperature, shell implosion time, etc.) are faithfully reproduced in calculations based on the one-dimensional SNDA (spectral nonequilibrium diffusion of absorption) program for nonequilibrium radiation gas dynamics. The calculations provide an explanation for the experimentally detected generation of a smaller number of neutrons in an experiment with a higher measured value for the ion temperature of DT gas

  18. EPR study of electron traps in x-ray-irradiated yttria-stabilized zirconia

    International Nuclear Information System (INIS)

    Azzoni, C.B.; Paleari, A.

    1989-01-01

    Single crystals of yttria-stabilized zirconia (12 mol % of Y 2 O 3 ) have been x-ray irradiated at room temperature. The electron paramagnetic resonance spectrum of the filled electron traps is analyzed in terms of a single oxygen vacancy type of defect with its symmetry axis along the left-angle 111 right-angle direction. The angular dependence of the linewidth and the asymmetry of the line shape are attributed to the disordered rearrangements of the anion sublattice surrounding the oxygen vacancy. This affects the local crystal fields and the directions of the symmetry axis of the defects

  19. EPR study of electron traps in x-ray-irradiated yttria-stabilized zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Azzoni, C.B.; Paleari, A. (Dipartimento di Fisica, Alessandro Volta dell' Universita di Pavia, via Bassi 6, 27100 Pavia, Italy (IT))

    1989-10-01

    Single crystals of yttria-stabilized zirconia (12 mol % of Y{sub 2}O{sub 3}) have been x-ray irradiated at room temperature. The electron paramagnetic resonance spectrum of the filled electron traps is analyzed in terms of a single oxygen vacancy type of defect with its symmetry axis along the {l angle}111{r angle} direction. The angular dependence of the linewidth and the asymmetry of the line shape are attributed to the disordered rearrangements of the anion sublattice surrounding the oxygen vacancy. This affects the local crystal fields and the directions of the symmetry axis of the defects.

  20. High linolenic acid mutant in soybean induced by X-ray irradiation

    International Nuclear Information System (INIS)

    Takagi, Y.; Hossain, A.B.M.M.; Yanagita, T.; Kusaba, S.

    1989-01-01

    Soybean [Glycine max (L.) Merr. cv. Bay] seeds were irradiated with X-rays (25kR) and the M 2 progeny was screened for changes in the fatty acid composition of seed oil. X-ray irradiation remarkably increased the variability of the fatty acid composition in the oil of the Bay cultivar. A mutant in which linolenic acid accounted for 18.4 per cent of the total oil cornpared with 9.4 per cent in the Bay cultivar was identified among 2006 M 2 plants. The M 3 generation of the mutant also showed a linolenic acid content approximately two times higher than that of the original variety

  1. Long-term effects of x-ray irradiation on reproductive function in male rats

    International Nuclear Information System (INIS)

    Varga, S.V.; Demchenko, V.N.; Chajkovskaya, L.V.; Reznikov, A.G.

    1994-01-01

    Reproductive function in male rats was studied in 1, 3 and 6 months after x-ray irradiation at doses of 2 and 3 Gy. It was been established that long-term effects of irradiation at a dose of 3 Gy are manifested through decrease in spermatozoa content in the epididymis and reduction of nucleie acid and protein content in the testes. Fertility of male rats under study significantly lowered shortly after irradiation and full recovery of fecundating ability was observed 6 months later. The effect of irradiation with a dose of 2 Gy was less pronounced

  2. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimitrova, A. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Georgieva, L. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Tzvetkova, E. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria)

    2006-09-15

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030+/-0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50days, an asymmetric singlet EPR line with g=2.0041+/-0.0005. Only apricot pulp gave a typical ''sugar-like'' EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g{sub ||}=2.0023+/-0.0003 and g{sub -}bar =2.0041+/-0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn{sup 2+} naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  3. Multifrequency EPR study on freeze-dried fruits before and after X-ray irradiation

    Science.gov (United States)

    Yordanov, N. D.; Aleksieva, K.; Dimitrova, A.; Georgieva, L.; Tzvetkova, E.

    2006-09-01

    X-, K- and Q-band EPR studies on lyophilized whole pulp parts of blue plum, apricot, peach, melon as well as achens and pulp separately of strawberry before and after X-ray irradiation are reported. Before irradiation all samples show in X band a weak singlet EPR line with g=2.0030±0.0005, except melon, which is EPR silent. Immediately after irradiation all samples exhibit complex fruit-depending spectra, which decay with time and change to give, in ca. 50 days, an asymmetric singlet EPR line with g=2.0041±0.0005. Only apricot pulp gave a typical "sugar-like" EPR spectrum. Singlet EPR lines recorded after irradiation in X -band are K- and Q-band resolved as typical anisotropic EPR spectra with g=2.0023±0.0003 and g⊥=2.0041±0.0005. In addition, K- and Q-band EPR spectra of all samples show a superposition with the six EPR lines of Mn 2+ naturally present in the fruits. The saturation behavior of the EPR spectra of achens of lyophilized and fresh strawberry is also studied. The differences in g factors of samples before and after X-ray irradiation might be used for the identification of radiation processing of fruits in the case of pulp and the differences in the EPR saturation behavior might be used for the achens of strawberry.

  4. Radiation Safety of Gamma, Electron and X Ray Irradiation Facilities. Specific Safety Guide (Spanish Edition)

    International Nuclear Information System (INIS)

    2015-01-01

    The objective of this Safety Guide is to provide recommendations on how to meet the requirements of the BSS with regard to irradiation facilities. This Safety Guide provides specific, practical recommendations on the safe design and operation of gamma, electron and X ray irradiators for use by operating organizations and the designers of these facilities, and by regulatory bodies. SCOPE. The facilities considered in this publication include five types of irradiator, whether operated on a commercial basis or for research and development purposes. This publication is concerned with radiation safety issues and not with the uses of irradiators, nor does it cover the irradiation of product or its quality management. The five types of irradiator are: - Panoramic dry source storage irradiators; - Underwater irradiators, in which both the source and the product being irradiated are under water; - Panoramic wet source storage irradiators; - Electron beam irradiation facilities, in which irradiation is performed in an area that is potentially accessible to personnel, but that is kept inaccessible during the irradiation process; - X ray irradiation facilities, in which irradiation is performed in an area that is potentially accessible to personnel, but that is kept inaccessible during the irradiation process. Consideration of non-radiation-related risks and of the benefits resulting from the operation of irradiators is outside the scope of this Safety Guide. The practices of radiotherapy and radiography are also outside the scope of this Safety Guide. Category I gamma irradiators (i.e. 'self-shielded' irradiators) are outside the scope of this Safety Guide

  5. Thermally and optically stimulated luminescence correlated processes in X-ray irradiated KCl:Eu2+

    International Nuclear Information System (INIS)

    Chernov, V.; Melendrez Ao, R.; Piters, T.M.; Barboza-Flores, M.

    2001-01-01

    The effect of optical bleaching on thermoluminescence (TL) and thermal bleaching on optically stimulated luminescence (OSL) outputs in X-ray irradiated KCl : Eu 2+ have been investigated. The X-ray induced glow curves reveal three main peaks located at 370, 410 and 470 K. Illumination with 560 nm light leads to a drastic change of the TL glow curve. The 470 K peak is destroyed during bleaching. The other peaks initially increase in intensity and only after sufficiently long bleaching begin to decrease. After long-time bleaching, the TL peaks in X-ray irradiated crystals look like the TL peaks found in UV irradiated crystals. The effect of thermal bleaching on OSL is also very pronounced. The temperature dependencies show a step-by-step decrease of the OSL intensity correlated with the positions of the TL peaks. The result obtained shows that centers responsible for the TL peaks participate in OSL, but this participation seems not to be direct and is complicated by processes accompanying the F center bleaching

  6. Quantitative measurements of oxidative stress in mouse skin induced by X-ray irradiation

    International Nuclear Information System (INIS)

    Chi, Cuiping; Tanaka, Ryoko; Okuda, Yohei; Ikota, Nobuo; Ozawa, Toshihiko; Anzai, Kazunori; Yamamoto, Haruhiko; Urano, Shiro

    2005-01-01

    To find efficient methods to evaluate oxidative stress in mouse skin caused by X-ray irradiation, several markers and methodologies were examined. Hairless mice were irradiated with 50 Gy X-rays and skin homogenates or skin strips were prepared. Lipid peroxidation was measured using the skin homogenate as the level of thiobarbituric acid reactive substances. The level of lipid peroxidation increased with time after irradiation and was twice that of the control at 78 h. Electron spin resonance (ESR) spectra of skin strips showed a clear signal for the ascorbyl radical, which increased with time after irradiation in a manner similar to that of lipid peroxidation. To measure levels of glutathione (GSH) and its oxidized forms (GSSG) simultaneously, two high performance liquid chromatography (HPLC) methods, sample derivatization with 1-fluoro-2,4-dinitrobenzene and detection with a UV detector (method A) and no derivatization and detection with an electrochemical detector (method B), were compared and the latter was found to be better. No significant change was observed within 24 h after irradiation in the levels of GSH and GSSG measured by method B. The GSH/GSSG ratio may be a less sensitive parameter for the evaluation of acute oxidative stress caused by X-ray irradiation in the skin. Monitoring the ascorbyl radical seems to be a good way to evaluate oxidative stress in skin in vivo. (author)

  7. Effect of propolis feeding on rat tissues damaged by X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hoon; Seo, Eul Won [Andong National Univ., Andong (Korea, Republic of); Ji, Tae Jeong [Kaya Univ., Goryeong (Korea, Republic of)

    2007-06-15

    Present study aimed to investigate the radioprotective effects of propolis feeding on rat tissues damaged by X-ray irradiation. It was shown that the number of white blood cell in X-ray irradiated group supplemented with propolis increased as much to those of the control group and also the GOT activities among the blood components were decreased after propolis feeding. The mineral contents such as Mg, Fe, Ca, Mn, Cu, Mo, Ni, As in liver were increased as compared with those of the control group but maintained lower level than those of only irradiated groups, implying that the propolis feeding elevated the recovery capability of white blood cell effectively and propolis have a potential resistance to cell damage by X-ray. According to histological observations of the testis, intestine and liver tissues which are irradiated after feeding propolis, the numbers of damaged undifferentiated cells were decreased in testis and the shape of the goblet cells and inner and outer muscular layers in intestine were restored to the original state and the hepatocytes and interlobular veins were shown intact in liver, suggesting that propolis has a potential capacity to restore cell shapes or resist deformation of cell.

  8. In vitro X-ray irradiation of human peripheral blood T lymphocytes enhances suppressor function

    International Nuclear Information System (INIS)

    Ogawa, H.; Tsunematsu, T.

    1983-01-01

    The effect of in vitro X-ray irradiation on human peripheral blood T lymphocytes was studied with regard to their suppressor activity related to the concanavalin A (Con A)-induced suppressor system. To generate suppressor T lymphocytes, purified human T lymphocytes were incubated for 3 days in the first culture, with or without Con A. These lymphocytes were irradiated with various doses of X-ray before, mid or after the culture. After doing a second culture for 6 days, the suppressive influence of these cells on T lymphocyte proliferation rates stimulated with allogeneic mononuclear cells, and B lymphocyte proliferation rates stimulated with pokeweed mitogen was measured. Irradiation of cultures to which Con A had not been added induced much the same level of suppressor activity as seen in the cultures with Con A. The suppressor activity gradually increased with time from the irradiation to the suppressor cell assay. Suppressor T lymphocytes were resistant to X-ray irradiation and independent of DNA synthesis. However, irradiation-induced enhancement was minimal in cultures incubated with con A, regardless of the irradiation time. (author)

  9. Radioprotective effect of chitosan in sub-lethally X-ray irradiated mice

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Yoshikazu; Ikota, Nobuo; Arima, Hiromi; Watanabe, Yoshito; Yukawa, Masae; Ozawa, Toshihiko [National Inst. of Radiological Sciences, Chiba (Japan); Kim, Hee-Sun [Korea Hydro and Nuclear Power Corp., Seoul (Korea, Republic of). Radiation Health Research Inst.; Bom, Hee-Seung; Kim, Young-Ho [Chonnam Univ., Kwangju (Korea, Republic of). Hospital

    2003-03-01

    The radioprotective effect of chitosan was studied in mice following whole-body X-ray irradiation. C3H/He mice were exposed to 7 Gy, and their survival rates were examined. The survival rates of chitosan-diet mice were about 20% higher than those of mice on a standard diet, and the rates dropped sharply to a plateau at day 10 after X-ray irradiation. The chitosan-diet mice had an increased weight ratio of spleen to body within the experimental period. The leukocyte, thrombocyte, and erythrocyte counts as well as the hematocrit and hemoglobin levels were recovered significantly and more rapidly in the chitosan-diet mice than the standard-diet mice at day 14 after irradiation. The scavenging abilities of chitosan were evaluated by the electron spin resonance (ESR) spin-trapping method. These observations suggested that chitosan led to hematopoetic activation and leuko-cytogenesis in mice after sub-lethal dose irradiation, and that the biological response might be caused by radical trapping or scavenging. (author)

  10. Influence of low doses chronic contamination on the progression of atheromatous pathology

    International Nuclear Information System (INIS)

    Le-Gallic, Clelia

    2015-01-01

    Large amounts of radionuclides were released in the environment after the Chernobyl (1986) or Fukushima-Daichii (2011) nuclear accidents, and mostly cesium 137. Populations living in contaminated territories are chronically exposed to radionuclides by ingestion of contaminated food. There is a real interrogation about the potential effects that could be induced following such ionizing exposure on physiological functions in the long term. Concerning the cardiovascular system, there is a correlation between the irradiation dose and the appearance of cardiovascular diseases. However, when we focused on post-accidental situations, with a low dose exposure, available data are not all in accordance, due to multifactorial aspect of these pathologies. Epidemiological results should be interpreted carefully. Thus, the aim of my thesis is to complete epidemiological studies about chronic internal? low dose exposure, using cesium 137, in an atheromatous context. Atherosclerosis and its consequences are known to be the main cause of mortality/morbidity in industrialized countries. Predisposed animals (ApoE-/- mice) were exposed to 137 Cs through the drinking water. The concentration range was 4 to 100 kBq.L -1 , to surround concentration found in contaminated territories around Chernobyl. Exposure times were 3, 6 or 9 months to follow atherosclerosis progression. After 3 months exposure, for the early stages, mice exposed to the highest dose presented an increase in some inflammatory cytokines, notably IFN-γ and VCAM-1, with an intimal-medial thickness increased compared to non-exposed animals. Moreover, at this time exposure, we noticed concomitant variation of gene expression of pro and anti-oxidative enzymes (p47, p67, GPx). These effects are only transient and do not persist over the time. Indeed, after 6 and 9 months exposure, atheromatous plaque observed in the aortic sinus, present more stability parameters than the control group (collagen), with also a decrease in pro

  11. Successful treatment of chronic recurrent multifocal osteomyelitis using low-dose radiotherapy. A case report

    International Nuclear Information System (INIS)

    Dietzel, Christian T.; Vordermark, Dirk; Schaefer, Christoph

    2017-01-01

    Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, which lacks an infectious genesis and predominantly involves the metaphysis of long bones. Common treatments range from nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids at first onset of disease, to immunosuppressive drugs and bisphosphonates in cases of insufficient remission. The therapeutic use of low-dose radiotherapy for CRMO constitutes a novelty. A 67-year-old female patient presented with radiologically proven CRMO affecting the right tibia/talus and no response to immunosuppressive therapy. Two treatment series of radiation therapy were applied with an interval of 6 weeks. Each series contained six fractions (three fractions per week) with single doses of 0.5 Gy, thus the total applied dose was 6 Gy. Ten months later, pain and symptoms of osteomyelitis had completely vanished. Radiotherapy seems to be an efficient and feasible complementary treatment option for conventional treatment refractory CRMO in adulthood. The application of low doses per fraction is justified by the inflammatory pathomechanism of disease. (orig.) [de

  12. Clinical effects of chronic low doses irradiation (11 years after Chernobyl accident)

    International Nuclear Information System (INIS)

    Romanenko, A.Y.; Bebeshko, V.G.

    1997-01-01

    Estimation of clinical effects of influence low doses of irradiation as the result of the Chernobyl accident on the human organism is presented in this report. The results of the investigations are concerning to changings in different organs and systems of inhabitants of the contamination territories and among clean-up workers. Increasing of morbidity of digestive and nervous systems is notified. Increase of thyroid cancer, chronic thyroidities and hypothyreouses is resisted in clean-up workers in dynamic observation. Highly morbidity of bronchopulmonal system and blood circulation system is revealed. High level of compensative and adaptive reactions of immune and hemopoietic systems is notified. Excesses of leukemias and lymphomas in inhabitants of the contamination territories is not demonstrated but tendency for increasing quantity cases of oncohematological diseases (leukemias, lymphomas, MDS) among clean-up workers IV-VII 1986 are absent. A dynamic of health state of children injured as a result of Chernobyl accident is characterized with continues negative tendencies. (author)

  13. The two strategies of plants to cope with chronic low dose irradiation

    International Nuclear Information System (INIS)

    Grodzinsky, D.M.

    2005-01-01

    Full text: The adaptive responses of plants to an increase in radioactivity of environment were established in radiobiological researches carried out in the Zone of the Chernobyl Nuclear Power Station. It has been shown that there are two types of adaptive strategies to the environment contaminated with radionuclides, namely ontogenetic and phylogenetic strategies. The ontogenetic adaptive strategy is attained by induction of DNA reparation. Increasing of the genetic variability in irradiated population performs the phylogenetic adaptive strategy. The mechanism of this strategy is associated with induction of genetic instability. Rise in the frequency of genetic recombination as well as heterozygosity is at the time essential components of phylogenetic adaptation. Ontogenetic and phylogenetic adaptation strategies are an important feature in coping of plants to the elevated chronic irradiation. Most likely plant cells as a stress signal into adaptive responses perceive the low doses of irradiation. (author)

  14. Effect of low dose radiation on expression of p16 gene in chronic myelogenous leukemia cells

    International Nuclear Information System (INIS)

    Zhang Longzhen; Ding Xin; Li Xiangyang; Cen Jiannong; Shen Hongjie; Chen Zixing

    2010-01-01

    Objective: To investigate the effect of low dose radiation on the expression on p16 gene in chronic myelogenous leukemia. Methods: Leukemic stem cells (LSCs) which expressed CD34 +, CD38 - and CD123 + were isolated from bone marrow cells obtained from twenty patients newly-diagnosedas chronic myeloid leukemia with EasySep TM magnet beads. Hematopoietic stem cells (HSCs) which expressed CD34 + and CD38 - were isolated from human cord blood cells obtained from twenty full-term deliveries with EasySep TM magnet beads as control. HSCs vs LSCs samples were further divided into three dose groups, including 0, 12.5 and 50 cGy, respectively. RT-PCR and real-time quantitative reverse transcription-polymerase chain reaction methods were used to detect mRNA expression of p16 gene in HSCs and LSCs after irradiation. Cells were harvested at different time for detection of cell cycle and apoptosis by flow cytometer. Results: p16 mRNA level in CML-LSCs was increased slightly at 12.5 cGy, and significantly increased at 50 cGy (Z=-3.39, P 0 /G 1 stagewas increased 48 h after 12.5 cGy irradiation, and 72 h post-irradiation with 50 cGy. The apoptosis rate of CML-LSCs was gradually raised after LDR, especially at 72 h post-irradiation of 50 cGy [(17.75±11.760% vs (6.13±4.71)%, Z=-2.37, P<0.01]. Conclusions: p16 gene transcription could be up-regulated by low dose radiation, which might provide a theoretical evidence for CML therapy and LDR in leukemic clinical application. (authors)

  15. Effect of Low-Dose Aspirin on Chronic Acid Reflux Esophagitis in Rats.

    Science.gov (United States)

    Masuda, Takahiro; Yano, Fumiaki; Omura, Nobuo; Tsuboi, Kazuto; Hoshino, Masato; Yamamoto, Se Ryung; Akimoto, Shunsuke; Kashiwagi, Hideyuki; Yanaga, Katsuhiko

    2018-01-01

    Clinical role of low-dose aspirin (LDA) in pathogenesis of gastroesophageal reflux disease is by far controversial. This can be attributed to the paucity of basic research detailing the mechanism of LDA-induced esophageal mucosal injury (EI) on underlying chronic acid reflux esophagitis (RE). The aim of this study was to clarify the effect of LDA on chronic RE in rats. Esophagitis was induced in 8-week-old male Wistar rats by ligating the border between forestomach and glandular portion with a 2-0 silk tie and covering the duodenum with a small piece of 18-Fr Nélaton catheter. Seventy-eight chronic RE rat models were divided into five treatment groups, consisting of orally administered vehicle (controls), and aspirin doses of 2, 5, 50 or 100 mg/kg once daily for 28 days. EI was assessed by gross area of macroscopic mucosal injury, severity grade of esophagitis and microscopic depth of infiltration by inflammatory cells. Area of esophagitis in animals with aspirin dose of 100 mg/kg/day showed a 36.5% increase compared with controls, although it failed to achieve statistical significance (p = 0.812). Additionally, the rate of severe EI was increased in animals with aspirin dose of 100 mg/kg/day as compared with controls (p aspirin (100 mg/kg/day) contributed in exacerbating preexisting EI. LDA (2 and 5 mg/kg/day), on the other hand, did not affect chronic RE in this model. LDA seems to be safe for use in patients with chronic RE.

  16. The use of low dose methotrexate in children with chronic anterior and intermediate uveitis.

    Science.gov (United States)

    Malik, A R; Pavesio, C

    2005-07-01

    To assess the efficacy of low dose methotrexate (MTX) therapy for children with chronic anterior and intermediate uveitis. A retrospective case review of 10 children who received MTX for chronic uveitis at a tertiary referral centre was performed. The following data were recorded for each patient: age, sex, race, duration of uveitis, primary diagnosis, anatomical localisation of uveitis, corticosteroid therapy, dose range of MTX, duration of MTX therapy, and side effects of MTX therapy. Several clinical parameters were evaluated to study the effect of MTX. These included visual acuity, anterior chamber inflammation, and topical and oral corticosteroid requirement. After MTX VA of 6/6 or better was present in 100% right eyes and 80% left eyes (p = 0.055 and p = 0.016, respectively). Anterior chamber inflammation decreased in 60% of children after MTX (p = 0.0168). The requirement of topical steroid decreased from a mean of 5.6 times a day before MTX to 1.5 times a day after MTX (p = 0.005). The dose of oral steroid decreased from a mean of 18 mg per day to 2.85 mg per day (p = 0.012). The most common adverse effect was nausea (20%). No patient required discontinuation of MTX because of side effects. MTX is effective and safe for chronic anterior and intermediate uveitis in children. An increase awareness of its efficacy is required among paediatricians and ophthalmologists to prevent sight threatening complication of chronic uveitis and its treatment with long term use of steroids.

  17. The effect of sex differences on induction of intestinal metaplasia in x-ray irradiated rats

    International Nuclear Information System (INIS)

    Watanabe, Hiromitsu; Takizawa, Shoichi; Terada, Yoritake; Naito, Masashi; Naito, Yukiko

    1980-01-01

    The effects of sex differences and ovarian resection on induction of intestinal metaplasia in x-ray irradiated mice were discussed. 1,000 rad of x-ray was irradiated to the stomach of female and male mice twice at intervals of 3 days. The range of intestinal metaplasia in male mice was wider than that in female mice. A total of 400 rad was irradiated to the whole body of mice which underwent ovarian resection (group 1), mice which underwent autotransplantation of the ovary after ovarian resection (group 2), and mice which underwent sham-ovarian resection (group 3). The incidence of intestinal metaplasia in the group 1 was significantly higher than that in the group 3. The weight of the uterus decreased gradually in order of the group 3, group 2, and group 1. It was suggested from above-mentioned results that disappearance or lowering of femal sex hormones, that is, male or androphacy, induced intestinal metaplasia. (Tsunoda, M.)

  18. Two cases of fibrosarcoma occurring in the x-ray irradiated site

    International Nuclear Information System (INIS)

    Wakamatsu, Katsuo; Mochizuki, Masako.

    1975-01-01

    The histological examination was carried out on the following 2 cases: One case was a 46-year-old man with psoriasis vulgaris who received x-ray irradiation continually for about 10 years on the gluteal regions and the extensive sides of both elbows. An ulcer appeared on the irradiated site and about 2 weeks later a tumor appeared. The other case was a 77-year-old man with prurigo in the pudendal region. Although the dose and duration of irradiation are unknown, the tumors appeared in the irradiated site 6-7 years after the start of irradiation. The histological examination of these cases revealed the clinical findings of fibrosarcoma. In the review of literature, 8 cases of irradiation sarcoma in Japan were discussed. (Kanao, N.)

  19. Forming a structure of the CoNiFe alloys by X-ray irradiation

    Science.gov (United States)

    Valko, Natalia; Kasperovich, Andrey; Koltunowicz, Tomasz N.

    The experimental data of electrodeposition kinetics researches and structure formation of ternary CoNiFe alloys deposited onto low-carbon steel 08kp in the presence of X-rays are presented. Relations of deposit rate, current efficiencies, element and phase compositions of CoNiFe coatings formed from sulfate baths with respect to cathode current densities (0.5-3A/dm2), electrolyte composition and irradiation were obtained. It is shown that, the CoNiFe coatings deposited by the electrochemical method involving exposure of the X-rays are characterized by more perfect morphology surfaces with less developed surface geometry than reference coatings. The effect of the X-ray irradiation on the electrodeposition of CoNiFe coatings promotes formatting of alloys with increased electropositive component and modified phase composition.

  20. Effects of X-ray irradiation combined with hyperthermia on human bone marrow cells

    International Nuclear Information System (INIS)

    Xie Huaijiang; Niu Rongjiu; Liu Xiaodong; Liu Huanqin

    1996-01-01

    The authors report on the effects of X-ray irradiation combined with hyperthermia on human bone marrow cells (BMC) in vitro. Observation was made on the morphology of treated cells under optic microscope and ultrastructural changes under electron microscope. The change was not obvious at first after treatment i,e, only the vacuolar degeneration was observed in a few cells under the EM. The survival of BMC alone after irradiation decreased with increase of the irradiation dose. The morphological changes included vacuolar degeneration of cells, swelling of mitochondria, and disintegration of nuclear membranes. The survival rate of BMC after irradiation combined with hyperthermia was significantly lower than that after treatment by either of them alone (P<0.01). The morphological changes were as follows: the cell structure was destroyed, the cell support system and cell organelles were destroyed, the cell membrane and nuclear membranes were destroyed, and the cell plasma and nuclear sap overflowed

  1. Response of mesenchymal stem cells in mice to 3.5 Gy X-ray irradiation

    International Nuclear Information System (INIS)

    Su Wenxia; Liu Huimin; Chen Yonghong; Zeng Wen; Liu Wenli; Sun Hanying

    2011-01-01

    Objective: To investigate the response of mesenchymal stem cells in mice to medium-dose X-ray irradiation in vitro. Methods: The mouse mesenchymal stem cell line C3H10T1/2 was submitted to 3.5 Gy X-ray irradiation. Hoechst33258 staining of adherent cells and Annexin V-FITC staining and flow cytometry analysis of suspension cells were performed respectively to assess cellular apoptosis at 3, 6, 12, 24, 48, 72 h and 1 week after irradiation. SA-β-gal staining was performed to analyze the cellular senescence at 24, 48, 72 h and 1 week after irradiation. The mRNA level of both Fas with its ligand FasL and p53 with its downstream target p21 WAF1 were measured by Real-Time PCR analysis. The expression of Fas protein was determined by immunofluorescence staining. Results: An increased apoptosis was observed at 3 h after irradiation with apoptosis rate 11.72% ± 1.61% (t=9.01, P<0.01), the apoptosis rate reached the peak level at 12 h 20.52% ± 1.96% (t=16.27, P<0.01), and then declined progressively to normal level at 48 h 4.93% ±0.46% (t=2.26, P>0.05). The SA-β-gal positive rate of post-radiation cells at 72 h was 53.33% ± 5.62%, significantly higher than that of normal control 3.24% ± 0.39% (t=17.77, P<0.01). The level of Fas, FasL mRNA was found to be elevated 3 h after irradiation with a peak at 12 h, and no differences were found l week later. The level of Fas protein was observed to reach the peak at 12 h after irradiation. The occurrence of peak level of Fas/FasL mRNA and protein was consistent with that of apoptosis of C3H10T1/2 cell. A transient up-regulation of p53, p21 WAF1 mRNA expression was found at 12 h after irradiation followed by a significant increase later at 72 h after irradiation. The occurrence of the two peaks of p53, p21 WAF1 mRNA expression were coincident with that of cellular apoptosis and senescence, respectively. The levels of p53, p21 WAF1 mRNA in senescence group were significantly higher than those of apoptosis group (t=17.85, 13

  2. High linolenic acid mutant in soybean induced by X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Y. [Saga Univ. (Japan); Hossain, A. B.M.M.; Yanagita, T.; Kusaba, S.

    1989-12-15

    Soybean [Glycine max (L.) Merr. cv. Bay] seeds were irradiated with X-rays (25kR) and the M{sub 2} progeny was screened for changes in the fatty acid composition of seed oil. X-ray irradiation remarkably increased the variability of the fatty acid composition in the oil of the Bay cultivar. A mutant in which linolenic acid accounted for 18.4 per cent of the total oil cornpared with 9.4 per cent in the Bay cultivar was identified among 2006 M{sub 2} plants. The M{sub 3} generation of the mutant also showed a linolenic acid content approximately two times higher than that of the original variety.

  3. Impact of gold nanoparticles combined to X-Ray irradiation on bacteria

    International Nuclear Information System (INIS)

    Simon-Deckers, A.; Gouget, B.; Carriere, M.; Brun, E.; Sicard-Roselli, C.

    2008-01-01

    Recent increase of multi drug-resistant bacteria represents a crucial issue of public health. As innovative approaches are required to face that problem, those emerging from nano-technology are of great interest. In that context we propose the possibility to use gold nano-particles combined with ionising radiation to destroy pathogenic bacteria. For that, we investigated the potential X-Rays enhanced reduction of bacterial cell viability, following nanoparticle exposure, on a bacterial model, Escherichia coli. Our first concern was to confirm the absence of toxicity of the colloidal solution used. Then, we developed an X-Ray irradiation system and showed that gold nanoparticles increased the efficiency of ionising radiation to induce bacteria cell death. (authors)

  4. Characterization of X-ray irradiator RS-2000; Caracterizacao do irradiador de raios X RS-2000

    Energy Technology Data Exchange (ETDEWEB)

    Mazaro, Sarah Jessica; Pavoni, Juliana Fernandes [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Departamento de Fisica; Silva, Maelson do Nascimento; Bianchini, Adriano L.B.; Amaral, Leonardo Lira do, E-mail: sarahmazaro@yahoo.com.br [Universidade de Sao Paulo (HC/FMRP/USP), Ribeirao Preto, SP (Brazil). Hospital das Clinicas. Faculdade de Medicina. Servico de Radioterapia

    2014-04-15

    Gamma irradiators are being replaced by the x - rays ones which are more economical and have greater safety benefits compared to the radionuclide irradiators. Some tests are usually performed to ensure quality control while working with radiation, as constancy, linearity, repeatability, reproducibility, radiometric survey and security tests. Evaluating the technical parameters and the instrument and equipment performance quickly. The irradiator characterization determines its operation, by ensuring that the deposited dose is the one desired. This study aims to characterize x-rays irradiators through dosimetric tests. The equipment used in this study stable in dose rate free space and regularity for safety test. Furthermore, the measurements were reproducible with a maximum variation of 10% and the radiometric survey showed that the results are consistent with the exemption requirements of radiological protection described in regulatory position 3.01/001:2011. (author)

  5. Study of serotonin effect on the yield of some damages in DNA after ultraviolet and x-ray irradiations

    International Nuclear Information System (INIS)

    Ivanova, Eh.V.; Frajkin, G.Ya.

    1985-01-01

    Using thin-layer two-dimensional chromatography serotonin effect on the yield of thymine dimers and appearance of n-glycoside strand breaks in DNA (thymine yield) after ultraviolet and X-ray irradiation is studied. It is shown that bound with DNA serotonin decreases formation of induced by ultraviolet thymine dimers but doesn't affect on the quantity of N-glycoside bond breaks in thymidine residues caused by X radiation. The obtained data are discussed in relation to the problem on mechanisms of realization of serotonin protective effect in the processes of yeast Saccharomyces photoprotection from ultraviolet and X-ray irradiation lethal effect

  6. Long-term storage method for soft X-ray irradiated 'Hyuganatsu' pollen

    International Nuclear Information System (INIS)

    Yano, S.; Tanaka, M.; Ohara, N.

    2008-01-01

    The long-term storage conditions for 'Hyuganatsu ' pollen that had been irradiated with soft X-rays was examined. This study, was aimed at production of 'Tosa-buntan' without formation of nuclear fruit. 1. We evaluated the germination rate of pollen that had been irradiated with soft X-ray (500 or 1,000 Gy) and stored at 3 deg C, -20 deg C, and -40 deg C. The germination rate was the same as that of unirradiated pollen, even after storage for 1 year. Soft X-ray irradiation did not influence the storage attributes of pollen. 2. In unirradiated pollen and pollen that had been irradiated with soft X-ray (500 or 1,000 Gy), temperature conditions necessary for storing from 3 months to 1 year were -20 deg C or less, and pollen stored at -40 deg C had a higher germination rate after 1 year. 3. The germination rate was 1% or less in 4 months if silica gel was sealed into a gas barrier bag with 1,000 Gy-irradiated pollen at a rate of 10:1 (w/w). The ability to germinate was completely lost after 1 year in these conditions. 4. We evaluated the effect of sealing methods on 1,000 Gy-irradiated pollen stored at -20 deg C. There was no difference in germination rates among pollen stored in gas-barrier bags, vacuum-packaged pollen, and pollen stored with nitrogen in gas-barrier bags. Moreover, the germination rate of 750 Gy-irradiated pollen stored at -20 deg C decreased from 3 months onwards when pollen was stored with a free-oxygen absorber (Ageless ZP). 5. Pollen that was treated with acetone before or after soft X-ray irradiation (750 Gy) withstood long-term storage of 1 year. Long-term storage was possible if pollen was stored at -20 deg C, as is the case for rough pollen

  7. AG, TL, and IRSL dosimetric properties in X-ray irradiated HPHT diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Tolano, M.I. [Programa de Posgrado, Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Melendrez, R.; Lancheros-Olmos, J.C.; Soto-Puebla, D.; Chernov, V.; Pedroza-Montero, M.; Barboza-Flores, M. [Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, Hermosillo, Sonora, 83000, Mexico (Mexico)

    2014-10-15

    HPHT diamonds have been studied for several years for their potential in different applications. In previous studies it has been found that the thermoluminescence (TL) glow curves of ''as-grown'' HPHT diamonds are non-reproducible. In this work, we study the afterglow (AG), thermoluminescent (TL), and optically stimulated luminescence (OSL) response of commercial samples of synthetic HPHT type-Ib diamond crystals exposed to X-ray irradiation (0.75 mA, 35 kV) at a dose rate of 0.624 Gy/s, after a high gamma ({sup 60}Co) dose irradiation of 500 kGy followed by a thermal treatment at 1073 K for 1 h in nitrogen atmosphere. Deconvolution of the TL glow curves shows four peaks, located around 379, 509, 561, and 609 K. The crystals exhibit evident AG recorded for 300 s immediately after X-ray irradiation, due to the thermal emptying of the traps responsible for the low-temperature TL peaks (below 400 K). The stimulation of irradiated crystals with 870-nm light, creates pronounced OSL and destroys all TL peaks with the exception of the high-temperature peak at 609 K. The dose responses of the integrated AG, TL, and OSL are linear in the range of 0.6-5 Gy and saturated at higher doses. The reproducibility of AG, TL, and OSL measurements is about 5%. The fading in the first hour of storage in dark conditions at RT of TL signal of HPHT diamond is mainly associated to the emptying of the traps responsible for the 379-K TL peaks. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. X-ray irradiation of RC-MAP pre-stored for various numbers of days. Effect of X-ray irradiation on RC-MAP and reuse of RC-MAP after irradiation

    International Nuclear Information System (INIS)

    Yamada, Naotomo; Nagumo, Fumio; Kawasaki, Seiji; Matsuzaki, Miwako; Tadano, Jutaro

    1995-01-01

    X-ray irradiation is currently in wide use as a means of preventing post-transfusion graft-versus-host disease (PT-GVHD). In this study, we evaluated the effects of X-ray irradiation on RC-MAP pre-stored for various numbers of days, and assessed how long irradiated RC-MAP can be stored. RC-MAP was irradiated at a dosage of 15 Gy at 1, 7, 14, 21 or 28 days after blood collection. These specimens were referred to as group I, II, III, IV and V (X-ray-irradiated groups), respectively. Non-irradiated RC-MAP was used as the control. Results showed that plasma K concentration increased after X-ray irradiation. It is therefore advisable that RC-MAPs be used immediately in infants and in renal failure. However, to maximize the efficiency of blood product use, it seemed possible that groups I and II could be used within two weeks after irradiation, and group III within one week. On the basis of this increase in K concentration, however, groups IV and V plasma should be used immediately after irradiation. (author)

  9. Chronic low-dose ultraviolet-induced mutagenesis in nucleotide excision repair-deficient cells.

    Science.gov (United States)

    Haruta, Nami; Kubota, Yoshino; Hishida, Takashi

    2012-09-01

    UV radiation induces two major types of DNA lesions, cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidine photoproducts, which are both primarily repaired by nucleotide excision repair (NER). Here, we investigated how chronic low-dose UV (CLUV)-induced mutagenesis occurs in rad14Δ NER-deficient yeast cells, which lack the yeast orthologue of human xeroderma pigmentosum A (XPA). The results show that rad14Δ cells have a marked increase in CLUV-induced mutations, most of which are C→T transitions in the template strand for transcription. Unexpectedly, many of the CLUV-induced C→T mutations in rad14Δ cells are dependent on translesion synthesis (TLS) DNA polymerase η, encoded by RAD30, despite its previously established role in error-free TLS. Furthermore, we demonstrate that deamination of cytosine-containing CPDs contributes to CLUV-induced mutagenesis. Taken together, these results uncover a novel role for Polη in the induction of C→T transitions through deamination of cytosine-containing CPDs in CLUV-exposed NER deficient cells. More generally, our data suggest that Polη can act as both an error-free and a mutagenic DNA polymerase, depending on whether the NER pathway is available to efficiently repair damaged templates.

  10. Low-dose computed tomography volumetry for subtyping chronic lung allograft dysfunction.

    Science.gov (United States)

    Saito, Tomohito; Horie, Miho; Sato, Masaaki; Nakajima, Daisuke; Shoushtarizadeh, Hassan; Binnie, Matthew; Azad, Sassan; Hwang, David M; Machuca, Tiago N; Waddell, Thomas K; Singer, Lianne G; Cypel, Marcelo; Liu, Mingyao; Paul, Narinder S; Keshavjee, Shaf

    2016-01-01

    The long-term success of lung transplantation is challenged by the development of chronic lung allograft dysfunction (CLAD) and its distinct subtypes of bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). However, the current diagnostic criteria for CLAD subtypes rely on total lung capacity (TLC), which is not always measured during routine post-transplant assessment. Our aim was to investigate the utility of low-dose 3-dimensional computed tomography (CT) lung volumetry for differentiating RAS from BOS. This study was a retrospective evaluation of 63 patients who had developed CLAD after bilateral lung or heart‒lung transplantation between 2006 and 2011, including 44 BOS and 19 RAS cases. Median post-transplant follow-up was 65 months in BOS and 27 months in RAS. The median interval between baseline and the disease-onset time-point for CT volumetry was 11 months in both BOS and RAS. Chronologic changes and diagnostic accuracy of CT lung volume (measured as percent of baseline) were investigated. RAS showed a significant decrease in CT lung volume at disease onset compared with baseline (mean 3,916 ml vs 3,055 ml when excluding opacities, p volumetry is a useful tool to differentiate patients who develop RAS from those who develop BOS. Copyright © 2016 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

  11. Larval x-ray irradiation influences protein expression in pupae of the Oriental fruit fly, Bactrocera Dorsalis

    Science.gov (United States)

    Third instar larvae were exposed to X-ray treatment of the Oriental fruit fly, Bactrocera dorsalis. Irradiated pupae were collected daily. Biological performance parameters of pupae and adults of larvae treated with X-ray irradiation were evaluated. Standard proteomics procedures such as densitometr...

  12. ROS enhancement by silicon nanoparticles in X-ray irradiated aqueous suspensions and in glioma C6 cells

    International Nuclear Information System (INIS)

    David Gara, Pedro M.; Garabano, Natalia I.; Llansola Portoles, Manuel J.; Moreno, M. Sergio; Dodat, Diego; Casas, Oscar R.; Gonzalez, Mónica C.; Kotler, Mónica L.

    2012-01-01

    The capability of silicon nanoparticles to increase the yield of reactive species upon 4 MeV X-ray irradiation of aqueous suspensions and C6 glioma cell cultures was investigated. ROS generation was detected and quantified using several specific probes. The particles were characterized by FTIR, XPS, TEM, DLS, luminescence, and adsorption spectroscopy before and after irradiation to evaluate the effect of high energy radiation on their structure. The total concentration of O 2 •− /HO 2 • , HO • , and H 2 O 2 generated upon 4-MeV X-ray irradiation of 6.4 μM silicon nanoparticle aqueous suspensions were on the order of 10 μM per Gy, ten times higher than that obtained in similar experiments but in the absence of particles. Cytotoxic 1 O 2 was generated only in irradiation experiments containing the particles. The particle surface became oxidized to SiO 2 and the luminescence yield reduced with the irradiation dose. Changes in the surface morphology did not affect, within the experimental error, the yields of ROS generated per Gy. X-ray irradiation of glioma C6 cell cultures with incorporated silicon nanoparticles showed a marked production of ROS proportional to the radiation dose received. In the absence of nanoparticles, the cells showed no irradiation-enhanced ROS generation. The obtained results indicate that silicon nanoparticles of 1 O 2 upon X-ray irradiation opens novel approaches in the design of therapy strategies.

  13. Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation.

    Science.gov (United States)

    Attar, A; Lémann, M; Ferguson, A; Halphen, M; Boutron, M C; Flourié, B; Alix, E; Salmeron, M; Guillemot, F; Chaussade, S; Ménard, A M; Moreau, J; Naudin, G; Barthet, M

    1999-02-01

    Polyethylene glycol (PEG) 3350 is a non-absorbable, non-metabolised osmotic agent used in lavage solutions for gut cleansing. To compare the efficacy of PEG and lactulose in chronic constipation. A total of 115 patients with chronic constipation entered a multicentre, randomised, comparative trial. They initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were given an option to change the dose to one or three sachets/day, depending on response. Ninety nine patients completed the trial. After four weeks, patients in the PEG group (n=50) had a higher number of stools and a lower median daily score for straining at stool than patients in the lactulose group (n=49). Overall improvement was greater in the PEG group. Clinical tolerance was similar in the two groups, but flatus was less frequently reported in the PEG group. The mean number of liquid stools was higher in the PEG group but the difference was significant only for the first two weeks. There were no serious adverse events and no significant change in laboratory tests in either group. At the end of the study, the number of sachets used by the patients was 1.6 (0.7)/day in the PEG group and 2.1 (0.7)/day in the lactulose group. Sixty one patients completed a further two months open study of one to three sachets PEG daily; there was no loss of efficacy and no serious toxicity. Low dose PEG 3350 was more effective than lactulose and better tolerated.

  14. The metabolomic approach identifies a biological signature of low-dose chronic exposure to Cesium 137

    International Nuclear Information System (INIS)

    Grison, S.; Grandcolas, L.; Martin, J.C.

    2012-01-01

    Reports have described apparent biological effects of 137 Cs (the most persistent dispersed radionuclide) irradiation in people living in Chernobyl-contaminated territory. The sensitive analytical technology described here should now help assess the relation of this contamination to the observed effects. A rat model chronically exposed to 137 Cs through drinking water was developed to identify biomarkers of radiation-induced metabolic disorders, and the biological impact was evaluated by a metabolomic approach that allowed us to detect several hundred metabolites in biofluids and assess their association with disease states. After collection of plasma and urine from contaminated and non-contaminated rats at the end of the 9-months contamination period, analysis with a liquid chromatography coupled to mass spectrometry (LC-MS) system detected 742 features in urine and 1309 in plasma. Biostatistical discriminant analysis extracted a subset of 26 metabolite signals (2 urinary, 4 plasma non-polar, and 19 plasma polar metabolites) that in combination were able to predict from 68 up to 94% of the contaminated rats, depending on the prediction method used, with a misclassification rate as low as 5.3%. The difference in this metabolic score between the contaminated and non-contaminated rats was highly significant (P=0.019 after ANOVA cross-validation). In conclusion, our proof-of-principle study demonstrated for the first time the usefulness of a metabolomic approach for addressing biological effects of chronic low-dose contamination. We can conclude that a metabolomic signature discriminated 137 Cs-contaminated from control animals in our model. Further validation is nevertheless required together with full annotation of the metabolic indicators. (author)

  15. Successful treatment of chronic recurrent multifocal osteomyelitis using low-dose radiotherapy. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Dietzel, Christian T.; Vordermark, Dirk [Klinikum der Martin-Luther-Universitaet Halle-Wittenberg, Universitaetslinik und Poliklinik fuer Strahlentherapie, Halle (Saale) (Germany); Schaefer, Christoph [Klinikum der Martin-Luther-Universitaet Halle-Wittenberg, Universitaetsklinik und Poliklinik fuer Innere Medizin II, Halle (Saale) (Germany)

    2017-03-15

    Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, which lacks an infectious genesis and predominantly involves the metaphysis of long bones. Common treatments range from nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids at first onset of disease, to immunosuppressive drugs and bisphosphonates in cases of insufficient remission. The therapeutic use of low-dose radiotherapy for CRMO constitutes a novelty. A 67-year-old female patient presented with radiologically proven CRMO affecting the right tibia/talus and no response to immunosuppressive therapy. Two treatment series of radiation therapy were applied with an interval of 6 weeks. Each series contained six fractions (three fractions per week) with single doses of 0.5 Gy, thus the total applied dose was 6 Gy. Ten months later, pain and symptoms of osteomyelitis had completely vanished. Radiotherapy seems to be an efficient and feasible complementary treatment option for conventional treatment refractory CRMO in adulthood. The application of low doses per fraction is justified by the inflammatory pathomechanism of disease. (orig.) [German] Die chronisch rekurrierende multifokale Osteomyelitis (CRMO) ist eine seltene autoimmunologische Erkrankung und befaellt vorzugsweise die Metaphysen der langen Roehrenknochen. Die Therapie umfasst nichtsteroidale Antirheumatika (NSAIDs) und Kortikosteroide bei Erstbefall und reicht bis hin zu Immunsuppressiva und Bisphosphonaten bei insuffizientem Ansprechen. Die Anwendung einer niedrigdosierten Radiatio stellt ein therapeutisches Novum dar. Eine 67-jaehrige Patientin stellte sich mit einem radiologisch gesicherten Befall im Sinne einer CRMO im Bereich des rechten Talus und der Tibia vor. Eine initiale Behandlung mit Immunsuppressiva verblieb erfolglos. Wir fuehrten zwei Bestrahlungsserien im Intervall von 6 Wochen durch. Jede Serie bestand aus 6 Fraktionen (3 Fraktionen/Woche), mit einer Einzeldosis von jeweils 0,5 Gy. Die

  16. Hard X-ray irradiation of cosmic silicate analogs: structural evolution and astrophysical implications

    Science.gov (United States)

    Gavilan, L.; Jäger, C.; Simionovici, A.; Lemaire, J. L.; Sabri, T.; Foy, E.; Yagoubi, S.; Henning, T.; Salomon, D.; Martinez-Criado, G.

    2016-03-01

    Context. Protoplanetary disks, interstellar clouds, and active galactic nuclei contain X-ray-dominated regions. X-rays interact with the dust and gas present in such environments. While a few laboratory X-ray irradiation experiments have been performed on ices, X-ray irradiation experiments on bare cosmic dust analogs have been scarce up to now. Aims: Our goal is to study the effects of hard X-rays on cosmic dust analogs via in situ X-ray diffraction. By using a hard X-ray synchrotron nanobeam, we seek to simulate cumulative X-ray exposure on dust grains during their lifetime in these astrophysical environments and provide an upper limit on the effect of hard X-rays on dust grain structure. Methods: We prepared enstatite (MgSiO3) nanograins, which are analogs to cosmic silicates, via the melting-quenching technique. These amorphous grains were then annealed to obtain polycrystalline grains. These were characterized via scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) before irradiation. Powder samples were prepared in X-ray transparent substrates and were irradiated with hard X-rays nanobeams (29.4 keV) provided by beamline ID16B of the European Synchrotron Radiation Facility (Grenoble). X-ray diffraction images were recorded in transmission mode, and the ensuing diffractograms were analyzed as a function of the total X-ray exposure time. Results: We detected the amorphization of polycrystalline silicates embedded in an organic matrix after an accumulated X-ray exposure of 6.4 × 1027 eV cm-2. Pure crystalline silicate grains (without resin) do not exhibit amorphization. None of the amorphous silicate samples (pure and embedded in resin) underwent crystallization. We analyze the evolution of the polycrystalline sample embedded in an organic matrix as a function of X-ray exposure. Conclusions: Loss of diffraction peak intensity, peak broadening, and the disappearance of discrete spots and arcs reveal the amorphization

  17. Reproductive toxicity in rats after chronic oral exposure to low dose of depleted uranium

    International Nuclear Information System (INIS)

    Li Rong; Ai Guoping; Xu Hui; Su Yongping; Cheng Tianmin; Leng Yanbing

    2007-01-01

    Objective: To study the reproductive toxicity in rats induced by low dose of depleted uranium (DU). Methods: Male and female rats(F 0 generation) were exposed to DU in food at doses of 0, 0.4, 4 and 40 mg·kg -1 ·d -1 for 160 days, respectively. Then the activities of enzymes in testis and sexual hormone contents in serum were detected. Mature male rats were mated with female rats exposed to the same doses for 14 days. Pregnant rate and normal labor rate in F 0 rats were detected, as well as the survival rate and weight of F 1 rats within 21 d after birth. Results: No adverse effects of DU on fertility were evident at any dose in F 0 rats. Compared with control group, the rate of pregnancy, normal labor, survival of offspring birth and offspring nurture in F 1 generation of high-dose group reduced to 40.0%, 33.3%, 33.3%, and 33.3%, respectively. The sexual hormone contents in F 0 generation exposed increased, but those in Fl rats decreased significantly. The activities of lactate dehydrogenase-X (LDH-X) decreased in F 1 rats exposed to high-dose of DU, and those of sorbitol dehydrogenase (SDH), LDH and Na + -K + -ATPase decreased in F 1 rats exposed to DU. Conclusions: Reproduction function, growth and development of F 0 rats are not obviously affected after chronic oral exposure to DU, while the toxicity effects in F 1 generation was observed at any dose. (authors)

  18. Chronic ingestion of a low dose of caffeine induces tolerance to the performance benefits of caffeine.

    Science.gov (United States)

    Beaumont, Ross; Cordery, Philip; Funnell, Mark; Mears, Stephen; James, Lewis; Watson, Phillip

    2017-10-01

    This study examined effects of 4 weeks of caffeine supplementation on endurance performance. Eighteen low-habitual caffeine consumers (caffeine (1.5-3.0 mg · kg -1 day -1 ; titrated) or placebo for 28 days. Groups were matched for age, body mass, V̇O 2peak and W max (P > 0.05). Before supplementation, all participants completed one V̇O 2peak test, one practice trial and 2 experimental trials (acute 3 mg · kg -1 caffeine [precaf] and placebo [testpla]). During the supplementation period a second V̇O 2peak test was completed on day 21 before a final, acute 3 mg · kg -1 caffeine trial (postcaf) on day 29. Trials consisted of 60 min cycle exercise at 60% V̇O 2peak followed by a 30 min performance task. All participants produced more external work during the precaf trial than testpla, with increases in the caffeine (383.3 ± 75 kJ vs. 344.9 ± 80.3 kJ; Cohen's d effect size [ES] = 0.49; P = 0.001) and placebo (354.5 ± 55.2 kJ vs. 333.1 ± 56.4 kJ; ES = 0.38; P = 0.004) supplementation group, respectively. This performance benefit was no longer apparent after 4 weeks of caffeine supplementation (precaf: 383.3 ± 75.0 kJ vs. postcaf: 358.0 ± 89.8 kJ; ES = 0.31; P = 0.025), but was retained in the placebo group (precaf: 354.5 ± 55.2 kJ vs. postcaf: 351.8 ± 49.4 kJ; ES = 0.05; P > 0.05). Circulating caffeine, hormonal concentrations and substrate oxidation did not differ between groups (all P > 0.05). Chronic ingestion of a low dose of caffeine develops tolerance in low-caffeine consumers. Therefore, individuals with low-habitual intakes should refrain from chronic caffeine supplementation to maximise performance benefits from acute caffeine ingestion.

  19. Effects of mecobalamin on testicular dysfunction induced by X-ray irradiation in mice

    International Nuclear Information System (INIS)

    Oshio, Shigeru; Yazaki, Tsunetada; Umeda, Takashi; Ozaki, Satoru; Ohkawa, Isao; Tajima, Tetsuya; Yamada, Takeshi; Mohri, Hideo.

    1991-01-01

    Experimental testicular dysfunction was produced by X-ray irradiation to the testes in mice. Mecobalamin (CH 3 -B 12 ) was orally administered at a daily dose of 0.01, 0.1 or 1 mg/kg six times a week for 8 weeks from the next day after the irradiation. The control mice received physiological saline in the same manner. On 4th- and 6th-week after the irradiation, the weights of testes and epididymides were decreased, although those of the body and accessory sex glands (seminal vesicle, coagulating gland and prostate) were nearly equal to those of non-irradiated mice. At the same time, the diameter of seminiferous tubules decreased and sperm parameters (sperm count, sperm motility and sperm abnormality) deteriorated. When CH 3 -B 12 (1 mg/kg) was administered, the diameter of seminiferous tubules increased and sperm parameters improved as compared to those of the control. The results indicate that CH 3 -B 12 improved the experimental testicular dysfunction in mice induced by the irradiation. These results suggest that CH 3 -B 12 might accelerate testicular function. (author)

  20. Effect of x-ray irradiation on the dentin matrix formation

    Energy Technology Data Exchange (ETDEWEB)

    You, Dong Soo [Dept. of Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Chang, Won Sik [Dept. of Prosthodontics, College of Dentistry, Seoul National University, Seoul (Korea, Republic of); Whang, Sung Myung [Dept. of Oral Antomy, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1976-11-15

    The authors has observed the effect of X-ray irradiation on the dentin matrix formation of the albino rat fetuses. The lower abdomen of the pregnant rats were exposed to X-ray on the 9 1/2th day of gestation, respectively 150, 250 and 350 rads. The fetuses of the right side of the same pregnant rats which were not exposed to X-ray were as controls. The results were as follows: 1) In the 150 rads irradiated fetuses, predentin formation was identical with control groups, but the arrangement of od ontoblasts was distorted, subodontoblastic layer was condensed with pulp cells, and blood capillaries were enlarged. 2) In the 250 rads irradiation, dentin matrix was imperfect or osteodentin was occurred. Short columnar or cuboidal od ontoblasts were presented and pulp cells were dispersed. Blood capillaries were congested. 3) 350 rads irradiated fetuses showed osteodentin matrix and numerous degenerated odontoblasts. Their dental papilla sh owed reticular atrophy and enlarged capillary.

  1. Radioprotective effect of Ganoderma lucidum (Leyss. ex. Fr. ) Karst after X-ray irradiation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, H.Y.; Lian, S.L.; Lin, C.C. (Kaohsiung Medical College (Taiwan))

    1990-01-01

    Six to seven week old male mice of ICR strain were exposed to 500 or 650 cGy of X-ray during experiments to determine if Ganoderma lucidum could be a factor in modification of radiation damage. Continuous intraperitoneal injection of the extract from Ganoderma lucidum before or after irradiation of 500 and 650 cGy of X-ray was found to improve the 30-day survival fractions of ICR mice, but wasn't significant by statistical analysis. The administration also enhanced the recoveries of the body weights and increased the recovery of hemograms of irradiated mice from radiation damage by injecting before or after radiation exposure, especially for the treatment of 500 cGy irradiation. The 10-day CFUs was significantly higher for Ganoderma lucidum treated groups than for untreated groups. However, the differences of radioprotective effect between the X-ray irradiated groups with Ganoderma lucidum pretreated and post-treated were not significant (p greater than 0.05).

  2. Degradation and crosslinking of perfluoroalkyl polyethers under X-ray irradiation in ultrahigh vacuum

    International Nuclear Information System (INIS)

    Mori, S.; Morales, W.

    1989-03-01

    Degradation of three types of commercially available perfluoroalkyl polyethers (PFPE)-Demnum S200, Fomblin Z25, and Krytox 16256-by X-ray irradiation was studied by using X-ray photoemission spectroscopy (XPS) and a mass spectrometer under ultra-high-vacuum conditions. The carbons in the polymers were characterized by chemical shifts of Cls binding energies. Gaseous products containing COF2 and low-molecular-weight fluorocarbons were formed. From Fomblin Z25, which has acetal linkages (-OCF2O-), a large quantity of COF2 gas was evolved. Liquid products became tacky after a long irradiation time, and some did not dissolve in Freon. High-pressure liquid chromatography (HPLC) showed that molecular weight distribution became broader and that higher molecular weight polymers were formed from Demnum and Krytox. We concluded from these results that degradation and cross-linking took place simultaneously. Demnum crosslinked more easily than the other fluids. The time dependence of both XPS spectra of Cls and mass spectra showed that C-O-bonded carbons in PFPE'S were removed faster than other carbons. There was no substrate effect on the degradation reaction because the first-order rate constants calculated from the change of gaseous products were similar when stainless steel (440C) and gold-coated surfaces were used. Metal fluorides were formed on stainless steel during the reaction. A mechanism for the degradation of PFPE'S is discussed on the basis of their molecular structures

  3. X-ray irradiation activates K+ channels via H2O2 signaling.

    Science.gov (United States)

    Gibhardt, Christine S; Roth, Bastian; Schroeder, Indra; Fuck, Sebastian; Becker, Patrick; Jakob, Burkhard; Fournier, Claudia; Moroni, Anna; Thiel, Gerhard

    2015-09-09

    Ionizing radiation is a universal tool in tumor therapy but may also cause secondary cancers or cell invasiveness. These negative side effects could be causally related to the human-intermediate-conductance Ca2+-activated-K+-channel (hIK), which is activated by X-ray irradiation and affects cell proliferation and migration. To analyze the signaling cascade downstream of ionizing radiation we use genetically encoded reporters for H2O2 (HyPer) and for the dominant redox-buffer glutathione (Grx1-roGFP2) to monitor with high spatial and temporal resolution, radiation-triggered excursions of H2O2 in A549 and HEK293 cells. The data show that challenging cells with ≥1 Gy X-rays or with UV-A laser micro-irradiation causes a rapid rise of H2O2 in the nucleus and in the cytosol. This rise, which is determined by the rate of H2O2 production and glutathione-buffering, is sufficient for triggering a signaling cascade that involves an elevation of cytosolic Ca2+ and eventually an activation of hIK channels.

  4. Effects of hyperthermia, x-ray irradiation and their combination on ascites tumor cells of mice

    International Nuclear Information System (INIS)

    Kaneko, Itsuo

    1982-01-01

    Fibrosarcoma ascites tumor cells (PB8) from NMRI mice were used to investigate cell loss by hyperthermia and/or x-ray irradiation. The tumor cells were labelled by an injection of 125 I-deoxyuridine to the abdominal cavity of the donors 2 days before the physical treatments. The labelled cells, transfered in test tubes, were heated at 44 0 C for 10-20 min and/or irradiated by x-ray at 250-1612 rad, and were transplanted in the recipient abdominal cavity as soon as possible after the treatments. The radioactivity of the tumor cells, as an indicator of cell loss, was measured with a gamma spectrometer. In the irradiated group, the ratio of cell loss increased in a dose-dependent manner, starting from the 4th day after the transplantation to the 9th day. In the heated group, the ratio of cell loss increased in proportion to the heating time, starting without delay after transplantation. In the combination group, the effect of the treatments was more marked than that by each single treatment. In the early stage of this group, cell loss was by heating and then, from the 4th day, the irradiation effect mostly dominated. It is concluded from the above results that cell loss by heating or irradiation is independent and that the effect of the combination is additive. (author)

  5. Radioprotective effect of Ganoderma lucidum (Leyss. ex. Fr.) Karst after X-ray irradiation in mice

    International Nuclear Information System (INIS)

    Hsu, H.Y.; Lian, S.L.; Lin, C.C.

    1990-01-01

    Six to seven week old male mice of ICR strain were exposed to 500 or 650 cGy of X-ray during experiments to determine if Ganoderma lucidum could be a factor in modification of radiation damage. Continuous intraperitoneal injection of the extract from Ganoderma lucidum before or after irradiation of 500 and 650 cGy of X-ray was found to improve the 30-day survival fractions of ICR mice, but wasn't significant by statistical analysis. The administration also enhanced the recoveries of the body weights and increased the recovery of hemograms of irradiated mice from radiation damage by injecting before or after radiation exposure, especially for the treatment of 500 cGy irradiation. The 10-day CFUs was significantly higher for Ganoderma lucidum treated groups than for untreated groups. However, the differences of radioprotective effect between the X-ray irradiated groups with Ganoderma lucidum pretreated and post-treated were not significant (p greater than 0.05)

  6. X-ray irradiation induced reversible resistance change in Pt/TiO2/Pt cells.

    Science.gov (United States)

    Chang, Seo Hyoung; Kim, Jungho; Phatak, Charudatta; D'Aquila, Kenneth; Kim, Seong Keun; Kim, Jiyoon; Song, Seul Ji; Hwang, Cheol Seong; Eastman, Jeffrey A; Freeland, John W; Hong, Seungbum

    2014-02-25

    The interaction between X-rays and matter is an intriguing topic for both fundamental science and possible applications. In particular, synchrotron-based brilliant X-ray beams have been used as a powerful diagnostic tool to unveil nanoscale phenomena in functional materials. However, it has not been widely investigated how functional materials respond to the brilliant X-rays. Here, we report the X-ray-induced reversible resistance change in 40-nm-thick TiO2 films sandwiched by Pt top and bottom electrodes, and propose the physical mechanism behind the emergent phenomenon. Our findings indicate that there exists a photovoltaic-like effect, which modulates the resistance reversibly by a few orders of magnitude, depending on the intensity of impinging X-rays. We found that this effect, combined with the X-ray irradiation induced phase transition confirmed by transmission electron microscopy, triggers a nonvolatile reversible resistance change. Understanding X-ray-controlled reversible resistance changes can provide possibilities to control initial resistance states of functional materials, which could be useful for future information and energy storage devices.

  7. Influence of X-ray irradiation on metabolic effects of adrenaline

    International Nuclear Information System (INIS)

    Szyszko, A.

    1976-01-01

    Effects of X-ray irradiation in the whole-body dose of 650 R on changes in glycogen levels in liver, and in either diaphragm and skeletal muscles, and on blood glucose levels, induced in 10 min by adrenaline, were investigated in starved mice. One day after the exposure, the drops in liver glycogen levels due to starvation were found to be highly reduced by previous irradiation. This resulted in an over dozen-fold relative elevation of liver glycogen content in relation to starved not irradiated mice. The post-irradiation accumulation of liver glycogen was found to disappear after administration of adrenaline. Also in diaphragm and skeletal muscles, the changes in muscle glycogen content, induced by irradiation of starved mice, have turned out to be abolished or even reversed by adrenaline, what reflected in reduction of elevated levels and elevation of those reduced. In starved mice during first three days following irradition, adrenaline was found to be ineffective in increasing blood sugar levels, whereas this its effects was noted in either not irradiated mice or on the fourth day after irradiation. (author)

  8. Relationship between X-ray irradiation and chromosomal damage in bone marrow tissue of mice

    International Nuclear Information System (INIS)

    Chaubey, R.C.; George, K.P.; Sundaram, K.

    1976-01-01

    X-ray induced chromosomal damage in bone-marrow tissue of male mice was studied using micronucleus technique. Dose response relationship was evaluated. Male Swiss mice received whole body x-ray irradiation at different doses from 25-1000 rads. Animals were sacrificed at the end of 24 hours, bone-marrow smears were made and stained in May-Grunwald-Giemsa. The preparatians were scored for the following types of aberrations: micronuclei in young erythocytes-polychromatic cells and in the mature erythrocytes-normechromatic cells. A dose dependent increase in the frequency of micronuclei in polychromatic cells up to a dose of 100 rads was observed. In addition the effect of post-irradiation duration on the frequency of micronuclei in polychromatic and normochromatic cells were studied. Male Swiss mice were exposed to 200 rads x-rays and were then sacrificed at different time intervals after irradiation and bone-marrow preparations were made and scored. Maximum polychromatic cells with micronuclei were observed in 24 hours post-irradiated animals, thereafter a decrease in the frequency of polychromatic cells with micronuclei was observed in 40 hours post irradiated animals. (author

  9. Intraocular levels of methotrexate after oral low-dose treatment in chronic uveitis.

    Science.gov (United States)

    Puchta, Joachim; Hattenbach, Lars-Olof; Baatz, Holger

    2005-01-01

    To determine the intraocular levels of methotrexate in low-dose treatment of noninfectious uveitis. One day after oral administration, the methotrexate level was measured in the aqueous humor and serum of a patient with noninfectious uveitis, who underwent cataract surgery. A fluorescence polarization immunoassay was used for determination. After oral administration, methotrexate was only measurable in aqueous humor but not in serum. In uveitis, orally administered low-dose methotrexate reaches detectable levels in aqueous humor, even in the absence of detectable levels in serum. Copyright (c) 2005 S. Karger AG, Basel.

  10. In-situ measurement of the strain relaxation of GaN nanograins during X-ray irradiation

    International Nuclear Information System (INIS)

    Choe, Hyeokmin; Lee, Sanghwa; Sohn, Yuri; Kim, Chinkyo

    2008-01-01

    GaN nanograins were grown on a c-plane sapphire substrate and their strain relaxation due to X-ray irradiation was investigated in-situ by utilizing synchrotron xray scattering. The GaN nanograins were constantly exposed to the synchrotron X-ray and θ-2θ scans through the (002) Bragg peak of GaN were repeatedly carried out during the irradiation. The Bragg peak of the compressively strained GaN nanograins gradually shifted toward higher angle, which implies that the GaN nanograins in compressive strain experienced strain relaxation during X-ray irradiation. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Sister chromatid exchanges in X-ray irradiated blood lymphocytes from patients with hereditary diseases with radioresistant DNA synthesis

    International Nuclear Information System (INIS)

    Pleskach, N.M.; Andriadze, M.I.; Mikhel'son, V.M.; Zhestyanikov, V.D.

    1988-01-01

    X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum from 2 and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons in necessary for SCE formation. Therefore the rate of SCF in X-irradiated cells of these patients decreases

  12. ROS enhancement by silicon nanoparticles in X-ray irradiated aqueous suspensions and in glioma C6 cells

    Energy Technology Data Exchange (ETDEWEB)

    David Gara, Pedro M. [CITOMA, Fundacion Avanzar, Instituto de Terapia Radiante S.A., CIO La Plata (Argentina); Garabano, Natalia I. [University of Buenos Aires, Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, UBA (Argentina); Llansola Portoles, Manuel J. [UNLP, INIFTA, Departamento de Quimica, Facultad de Ciencias Exactas (Argentina); Moreno, M. Sergio [Centro Atomico Bariloche (Argentina); Dodat, Diego; Casas, Oscar R. [CITOMA, Fundacion Avanzar, Instituto de Terapia Radiante S.A., CIO La Plata (Argentina); Gonzalez, Monica C., E-mail: gonzalez@inifta.unlp.edu.ar [UNLP, INIFTA, Departamento de Quimica, Facultad de Ciencias Exactas (Argentina); Kotler, Monica L., E-mail: kotler@qb.fcen.uba.ar [University of Buenos Aires, Departamento de Quimica Biologica, Facultad de Ciencias Exactas y Naturales, UBA (Argentina)

    2012-03-15

    The capability of silicon nanoparticles to increase the yield of reactive species upon 4 MeV X-ray irradiation of aqueous suspensions and C6 glioma cell cultures was investigated. ROS generation was detected and quantified using several specific probes. The particles were characterized by FTIR, XPS, TEM, DLS, luminescence, and adsorption spectroscopy before and after irradiation to evaluate the effect of high energy radiation on their structure. The total concentration of O{sub 2}{sup Bullet -}/HO{sub 2}{sup Bullet}, HO{sup Bullet}, and H{sub 2}O{sub 2} generated upon 4-MeV X-ray irradiation of 6.4 {mu}M silicon nanoparticle aqueous suspensions were on the order of 10 {mu}M per Gy, ten times higher than that obtained in similar experiments but in the absence of particles. Cytotoxic {sup 1}O{sub 2} was generated only in irradiation experiments containing the particles. The particle surface became oxidized to SiO{sub 2} and the luminescence yield reduced with the irradiation dose. Changes in the surface morphology did not affect, within the experimental error, the yields of ROS generated per Gy. X-ray irradiation of glioma C6 cell cultures with incorporated silicon nanoparticles showed a marked production of ROS proportional to the radiation dose received. In the absence of nanoparticles, the cells showed no irradiation-enhanced ROS generation. The obtained results indicate that silicon nanoparticles of <5 nm size have the potential to be used as radiosensitizers for improving the outcomes of cancer radiotherapy. Their capability of producing {sup 1}O{sub 2} upon X-ray irradiation opens novel approaches in the design of therapy strategies.

  13. Thermoluminescence study of X-ray irradiated muscovite mineral under various heating rate

    International Nuclear Information System (INIS)

    Kalita, J.M.; Wary, G.

    2014-01-01

    The thermoluminescence (TL) glow curves of X-ray irradiated micro-grain natural muscovite were recorded within 298–520 K at various linear heating rates (2 K/s, 4 K/s, 6 K/s, 8 K/s and 10 K/s). Natural TL of muscovite was checked, but no significant TL was observed within 298–520 K in any heating rate. Within the heating rate 2–10 K/s only a low temperature distinct peak was observed in the temperature range 348–357 K. The TL parameters such as activation energy, order of kinetic, geometrical symmetry factor and pre-exponential frequency factor were investigated from the glow peak by Peak Shape (PS) method and Computerized Glow Curve Deconvolution (CGCD) technique. At lowest heating rate the glow peak obeys non-first order kinetic and at the highest heating rate it follows the second order kinetic. The variation of peak integrals, peak maximum temperatures, FWHM and activation energy with heating rates were investigated, and the glow curves at higher rates were found to be influenced by the presence of the thermal quenching. The thermal quenching activation energy and pre-exponential factor were calculated and found to be 2.31±0.02 eV and 3.46×10 14 s −1 , respectively. -- Highlights: • Muscovite is a silicate mineral with chemical formula KAl 2 (Si 3 Al)O 10 (OH,F) 2 . • TL of natural and X-ray induced muscovite was studied under various heating rates. • TL parameters were evaluated by Peak Shape and CGCD method. • Thermal quenching parameters (W and C) of muscovite were evaluated

  14. Biological X-ray irradiator characterization for use with small animals and cells.

    Science.gov (United States)

    Bruno, A Colello; Mazaro, S J; Amaral, L L; Rego, E M; Oliveira, H F; Pavoni, J F

    2017-03-02

    This study presents the characterization of an X-ray irradiator through dosimetric tests, which confirms the actual dose rate that small animals and cells will be exposed to during radiobiological experiments. We evaluated the linearity, consistency, repeatability, and dose distribution in the positions in which the animals or cells are placed during irradiation. In addition, we evaluated the performance of the X-ray tube (voltage and tube operating current), the radiometric survey (leakage radiation) and safety devices. The irradiator default setting was established as 160 kV and 25 mA. Tests showed that the dose rate was linear overtime (R2=1) and remained stable for long (constant) and short (repeatability) intervals between readings. The mean dose rate inside the animal cages was 1.27±0.06 Gy/min with a uniform beam of 95.40% (above the minimum threshold guaranteed by the manufacturer). The mean dose rate inside the cell plates was 0.92±0.19 Gy/min. The dose rate dependence with tube voltage and current presented a quadratic and linear relationship, respectively. There was no observed mechanical failure during evaluation of the irradiator safety devices and the radiometric survey obtained a maximum ambient equivalent dose rate of 0.26 mSv/h, which exempts it from the radiological protection requirements of the International Atomic Energy Agency. The irradiator characterization enables us to perform radiobiological experiments, and assists or even replaces traditional therapy equipment (e.g., linear accelerators) for cells and small animal irradiation, especially in early research stages.

  15. The effects of x-ray irradiation on the inner ear

    International Nuclear Information System (INIS)

    Kanagawa, Kiyoto

    1983-01-01

    Since the beginning of the 20th century, it has been known that the radiation can cause hearing loss, but the details of this process are not as well known as those of radiation effects on other organs. The author studied the effects of single dose of x-ray irradiation on the inner ear of guinea pigs by continuously measurement of cochlear microphonics (CM) and auditory brainstem responses (ABR) with permanent electrodes implanted on the round window and in the skull. With 2,000, 4,000, and 6,000 rad, slight conductive hearing impairment was observed in some guinea pigs. Severe sensorineural hearing loss was acutely induced by irradiation more than 8,000 rad. After 10,000 rad irradiation, both CM and ABR to air and bone conduction stimuli were usually enhanced by 20-50% above the pre-irradiation levels for one or two hours after completion of the irradiation, and they disappeared simultaneously about 6 hours after irradiation. Hearing impairment began earlier with increase in irradiation: about 10 hours at 8,000 rad, about 6 hours at 10,000 rad, and about 3 hours at 12,000 rad. Responses to high frequency sounds generally disappeared slightly earlier than those to low frequencies. The I-III interpeak latency of ABR didn't change after 10,000 rad irradiation. Endocochlear potential (EP) drop to about 30mV was observed about 7 hours after 10,000 rad irradiation. In the scanning electron micrographs, the sensory hairs in the outer and inner hair cells of every turn seemed to be normal 6 hours after 10,000 rad irradiation. In transmission electron microscopy, however, heavy damages were seen at the outer hair cells in the basal coil of the cochlea. (author)

  16. Biological X-ray irradiator characterization for use with small animals and cells

    Directory of Open Access Journals (Sweden)

    A. Colello Bruno

    Full Text Available This study presents the characterization of an X-ray irradiator through dosimetric tests, which confirms the actual dose rate that small animals and cells will be exposed to during radiobiological experiments. We evaluated the linearity, consistency, repeatability, and dose distribution in the positions in which the animals or cells are placed during irradiation. In addition, we evaluated the performance of the X-ray tube (voltage and tube operating current, the radiometric survey (leakage radiation and safety devices. The irradiator default setting was established as 160 kV and 25 mA. Tests showed that the dose rate was linear overtime (R2=1 and remained stable for long (constant and short (repeatability intervals between readings. The mean dose rate inside the animal cages was 1.27±0.06 Gy/min with a uniform beam of 95.40% (above the minimum threshold guaranteed by the manufacturer. The mean dose rate inside the cell plates was 0.92±0.19 Gy/min. The dose rate dependence with tube voltage and current presented a quadratic and linear relationship, respectively. There was no observed mechanical failure during evaluation of the irradiator safety devices and the radiometric survey obtained a maximum ambient equivalent dose rate of 0.26 mSv/h, which exempts it from the radiological protection requirements of the International Atomic Energy Agency. The irradiator characterization enables us to perform radiobiological experiments, and assists or even replaces traditional therapy equipment (e.g., linear accelerators for cells and small animal irradiation, especially in early research stages.

  17. SOFT X-RAY IRRADIATION OF PURE CARBON MONOXIDE INTERSTELLAR ICE ANALOGUES

    Energy Technology Data Exchange (ETDEWEB)

    Ciaravella, A.; Candia, R.; Collura, A. [INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Jimenez-Escobar, A.; Munoz Caro, G. M. [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Cecchi-Pestellini, C. [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Italy); Giarrusso, S. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy); Barbera, M., E-mail: aciaravella@astropa.unipa.it [Dipartimento di Scienze Fisiche and Astronomiche, Universita di Palermo, Sezione di Astronomia, Piazza del Parlamento 1, I-90134 Palermo (Italy)

    2012-02-10

    There is an increasing evidence for the existence of large organic molecules in the interstellar and circumstellar medium. Very few among such species are readily formed in conventional gas-phase chemistry under typical conditions of interstellar clouds. Attention has therefore focused on interstellar ices as a potential source of these relatively complex species. Laboratory experiments show that irradiation of interstellar ice analogues by fast particles or ultraviolet radiation can induce significant chemical complexity. However, stars are sources of intense X-rays at almost every stage of their formation and evolution. Such radiation may thus provide chemical changes in regions where ultraviolet radiation is severely inhibited. After H{sub 2}O, CO is often the most abundant component of icy grain mantles in dense interstellar clouds and circumstellar disks. In this work we present irradiation of a pure carbon monoxide ice using a soft X-ray spectrum peaked at 0.3 keV. Analysis of irradiated samples shows formation of CO{sub 2}, C{sub 2}O, C{sub 3}O{sub 2}, C{sub 3}, C{sub 4}O, and CO{sub 3}/C{sub 5}. Comparison of X-rays and ultraviolet irradiation experiments, of the same energy dose, shows that X-rays are more efficient than ultraviolet radiation in producing new species. With the exception of CO{sub 2}, X-ray photolysis induces formation of a larger number of products with higher abundances, e.g., C{sub 3}O{sub 2} column density is about one order of magnitude higher in the X-ray experiment. To our knowledge this is the first report on X-ray photolysis of CO ices. The present results show that X-ray irradiation represents an efficient photo-chemical way to convert simple ices to more complex species.

  18. Level of coenzyme A and the activity of certain dehydrogenases under chronic low dose X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cherkasova, L A; Novik, V A; Tsychun, G F [AN Belorusskoj SSR, Minsk. Inst. Fiziologii

    1975-01-01

    A study was made of the effect of long-term x ray irradiation (cumulative dose 50 R) on: the content of co-enzyme A (KoA) in the brain and liver, the activity of a number of oxydizing reducing enzymes in the brain mitochondria and heart muscle, and the blood glucocorticoid content. It was established that the metabolism of brain and liver KoA is quite stable, the enzymes of the brain tricarbonic acids and pyruvate-dehydrogenase cycle are labile.

  19. Low-dose radiation effects on the evolution of chronic dystrophical processes in cornea and clouding of crystalline lens

    International Nuclear Information System (INIS)

    Gajdaj, Yu.V.; Gajdaj, V.M.

    1993-01-01

    Low-dose radiation effects on the course of chronic dystrophical processes in cornea and the dynamics of crystalline lens clouding of involution age genesis are investigated in the patients participated in Chernobyl accident response. Examples of the concrete pathological cases are considered. It was stated that the above dose effects led to exacerbation of the chronic slack dystrophical processes in cornea and intensification of the development of cornea primary dystrophy. In a number of cases the intensification of development of crystalline lens clouding takes place resulted in the cataract for 2-3 years

  20. The induction of a tumor suppressor gene (p53) expression by low-dose radiation and its biological meaning

    International Nuclear Information System (INIS)

    Ohnishi, Takeo

    1997-01-01

    I report the induced accumulation of wild-type p53 protein of a tumor suppressor gene within 12 h in various organs of rats exposed to X-ray irradiation at low doses (10-50 cGy). The levels of p53 in some organs of irradiated rats were increased about 2- to 3-fold in comparison with the basal p53 levels in non-irradiated rats. Differences in the levels of p53 induction after low-dose X-ray irradiation were observed among the small intestine, bone marrow, brain, liver, adrenal gland, spleen, hypophysis and skin. In contrast, there was no obvious accumulation of p53 protein in the testis and ovary. Thus, the induction of cellular p.53 accumulation by low-dose X-ray irradiation in rats seems to be organ-specific. I consider that cell type, and interactions with other signal transduction pathways of the hormone system, immune system and nervous system may contribute to the variable induction of p53 by low-dose X-ray irradiation. I discussed the induction of p53 by radiation and its biological meaning from an aspect of the defense system for radiation-induced cancer. (author)

  1. Seizures associated with low-dose tramadol for chronic pain treatment

    Science.gov (United States)

    Beyaz, Serbülent Gökhan; Sonbahar, Tuğba; Bayar, Fikret; Erdem, Ali Fuat

    2016-01-01

    The management of cancer pain still poses a major challenge for clinicians. Tramadol is a centrally acting synthetic opioid analgesic. Its well-known side effects include nausea, vomiting, and dizziness; seizures are a rare side effect. Some reports have found that tramadol triggers seizure activity at high doses, whereas a few preclinical studies have found that this seizure activity is not dose-related. We herein present a case involving a patient with laryngeal cancer who developed seizures while on low-dose oral tramadol. PMID:27212778

  2. Evaluation of chronic infectious interstitial pulmonary disease in children by low-dose CT-guided transthoracic lung biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Heyer, Christoph M.; Lemburg, Stefan P.; Kagel, Thomas; Nicolas, Volkmar [Ruhr-University of Bochum, Institute of Diagnostic Radiology, Interventional Radiology and Nuclear Medicine, BG Clinics Bergmannsheil, Bochum (Germany); Mueller, Klaus-Michael [Ruhr-University of Bochum, Institute of Pathology, BG Clinics Bergmannsheil, Bochum (Germany); Nuesslein, Thomas G.; Rieger, Christian H.L. [Ruhr-University of Bochum, Pediatric Hospital, Bochum (Germany)

    2005-07-01

    Children with chronic infectious interstitial lung disease often have to undergo open lung biopsy to establish a final diagnosis. Open lung biopsy is an invasive procedure with major potential complications. Transthoracic lung biopsy (TLB) guided by computed tomography (CT) is a less-invasive well-established procedure in adults. Detailing the role of low-dose CT-guided TLB in the enhanced diagnosis of chronic lung diseases related to infection in children. A group of 11 children (age 8 months to 16 years) underwent CT-guided TLB with a 20-gauge biopsy device. All investigations were done under general anaesthesia on a multidetector CT scanner (SOMATOM Volume Zoom, Siemens, Erlangen, Germany) using a low-dose protocol (single slices, 120 kV, 20 mAs). Specimens were processed by histopathological, bacteriological, and virological techniques. All biopsies were performed without major complications; one child developed a small pneumothorax that resolved spontaneously. A diagnosis could be obtained in 10 of the 11 patients. Biopsy specimens revealed chronic interstitial alveolitis in ten patients. In five patients Chlamydia pneumoniae PCR was positive, in three Mycoplasma pneumoniae PCR was positive, and in two Cytomegalovirus PCR was positive. The average effective dose was 0.83 mSv. Low-dose CT-guided TLB can be a helpful tool in investigating chronic infectious inflammatory processes in children with minimal radiation exposure. It should be considered prior to any open surgical procedure performed for biopsy alone. In our patient group no significant complication occurred. A disadvantage of the method is that it does not allow smaller airways and vessels to be assessed. (orig.)

  3. The Safety and Efficacy of Low-Dose Naltrexone in the Management of Chronic Pain and Inflammation in Multiple Sclerosis, Fibromyalgia, Crohn's Disease, and Other Chronic Pain Disorders.

    Science.gov (United States)

    Patten, Denise K; Schultz, Bob G; Berlau, Daniel J

    2018-03-01

    Chronic inflammatory diseases are complex to treat and have an impact on a large number of patients. Due to the difficulty of treating these diseases and the great impact on quality of life, patients often seek off-label, complimentary, or alternative medicines to gain relief from symptoms. Low-dose naltrexone has been used off-label for treatment of pain and inflammation in multiple sclerosis, Crohn's disease, fibromyalgia, and other diseases. Naltrexone is a mu-opioid receptor antagonist indicated by the U.S. Food and Drug Administration for opioid and alcohol dependence. It is hypothesized that lower than standard doses of naltrexone inhibit cellular proliferation of T and B cells and block Toll-like receptor 4, resulting in an analgesic and antiinflammatory effect. It is the purpose of this review to examine the evidence of the safety, tolerability, and efficacy of low-dose naltrexone for use in chronic pain and inflammatory conditions. Currently, evidence supports the safety and tolerability of low-dose naltrexone in multiple sclerosis, fibromyalgia, and Crohn's disease. Fewer studies support the efficacy of low-dose naltrexone, with most of these focusing on subjective measures such as quality of life or self-reported pain. These studies do demonstrate that low-dose naltrexone has subjective benefits over placebo, but evidence for more objective measures is limited. However, further randomized controlled trials are needed to determine the efficacy of low-dose naltrexone due to insufficient evidence supporting its use in these disease states. This review provides practitioners with the extent of low-dose naltrexone evidence so that they can be cognizant of situations where it may not be the most appropriate therapy. © 2018 Pharmacotherapy Publications, Inc.

  4. Effects of Low Dose Chronic Radiation and Heavy Metals on Plants and Their Fungal and Virus Infections

    Directory of Open Access Journals (Sweden)

    A Dmitriev

    2009-06-01

    Full Text Available The effects of low dose chronic radiation on plant disease resistance and fungal and virus infections have been studied. The results obtained in the 10-km Chernobyl zone demonstrated a decrease in plant disease resistance and appearance of a "new" population of stem rust agents of cereal with a high frequency of more virulent clones. Radionuclide contamination and heavy metals lead to wider virus spread and a higher diversity of virus species. The Chernobyl zone is a territory of enhanced risk and potential threats for the environment. A special type of monitoring of microevolution processes in plant pathogens should provide better understanding of how serious these potential threats are.

  5. Response of the upper atmosphere to variations in the solar soft x-ray irradiance. Ph.D. Thesis

    Science.gov (United States)

    Bailey, Scott Martin

    1995-01-01

    Terrestrial far ultraviolet (FUV) airglow emissions have been suggested as a means for remote sensing the structure of the upper atmosphere. The energy which leads to the excitation of FUV airglow emissions is solar irradiance at extreme ultraviolet (EUV) and soft x-ray wavelengths. Solar irradiance at these wavelengths is known to be highly variable; studies of nitric oxide (NO) in the lower thermosphere have suggested a variability of more than an order of magnitude in the solar soft x-ray irradiance. To properly interpret the FUV airflow, the magnitude of the solar energy deposition must be known. Previous analyses have used the electron impact excited Lyman-Birge-Hopfield (LBH) bands of N2 to infer the flux of photoelectrons in the atmosphere and thus to infer the magnitude of the solar irradiance. This dissertation presents the first simultaneous measurements of the FUV airglow, the major atmospheric constituent densities, and the solar EUV and soft x-ray irradiances. The measurements were made on three flights of an identical sounding rocket payload at different levels of solar activity. The linear response in brightness of the LBH bands to variations in solar irradiance is demonstrated. In addition to the N2 LBH bands, atomic oxygen lines at 135.6 and 130.4 nm are also studied. Unlike the LBH bands, these emissions undergo radiative transfer effects in the atmosphere. The OI emission at 135.6 nm is found to be well modeled using a radiative transfer calculation and the known excitation processes. Unfortunately, the assumed processes leading to OI 130.4 nm excitation are found to be insufficient to reproduce the observed variability of this emission. Production of NO in the atmosphere is examined; it is shown that a lower than previously reported variability in the solar soft x-ray irradiance is required to explain the variability of NO.

  6. Effects of X-ray irradiation on the microbial growth and quality of flue-cured tobacco during aging

    International Nuclear Information System (INIS)

    Wang, J.J.; Xu, Z.C.; Fan, J.L.; Wang, Y.; Tian, Z.J.; Chen, Y.T.

    2015-01-01

    X-ray irradiation was evaluated for improving microbial safety and the quality of flue-cured tobacco during aging. Tobacco samples were irradiated at doses of 0, 1, 2, 3 and 5 kGy and stored for 12 months under normal storage conditions or in a high-humidity (RH>70%) room. Microbiological data indicated that the population of total aerobic bacteria was significantly decreased with increasing irradiation doses. In particular, a dose of 2 kGy was effective for the decontamination of fungi from the tested samples, with a 0.93 log CFU/g reduction for bacteria. The control and 1 kGy X-ray treated tobacco samples were became rotted and moldy after the 12th month, whereas those treated with 2, 3 and 5 kGy had no detectable mold during 12 months of storage at high humidity. Chemical measurements showed that irradiation up to 3 kGy did not affect the total nitrogen, nicotine, reducing and total sugars, ratio of total nitrogen to nicotine and sugar-to-nicotine ratio. Furthermore, sensory evaluation results also showed that X-ray irradiation did not affect sensory scores with irradiation at a dose <3 kGy. Based on these results, X-ray irradiation dose in the range of 2–3 kGy is recommended for the decontamination of fungi from flue-cured tobacco. - Highlights: • 2 kGy dose improved sufficiently the microbial safety of flue-cured tobacco. • The doses up to 3 kGy did not affect the chemical components. • A dose <3 kGy had no effect on sensory scores. • The recommended dose to irradiated flue-cured tobacco is the range of 2–3 kGy

  7. Radiosensitivity of grapevines. Empirical modelling of the radiosensitivity of some clones to x-ray irradiation. Pt. 1

    International Nuclear Information System (INIS)

    Koeroesi, F.; Jezierska-Szabo, E.

    1999-01-01

    Empirical and formal (Poisson) models were utilized, applying experimental growth data to characterize the radiosensitivity of six grapevine clones to X-ray irradiation. According to the radiosensitivity constants (k), target numbers (n) and volumes, GR 37 doses and energy deposition, the following radiosensitivity order has been found for various vine brands: Chardonnay clone type < Harslevelue K. 9 < Koevidinka K. 8 < Muscat Ottonel clone type < Irsai Oliver K. 11 < Cabernet Sauvignon E. 153. The model can be expanded to describe the radiosensitivity of other plant species and varieties, and also the efficiency of various radioprotecting agents and conditions. (author)

  8. The status of Tsukuba BNCT trial: BPA-based boron neutron capture therapy combined with X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T., E-mail: tetsu_tsukuba@yahoo.co.jp [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan)] [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Nakai, K. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Nariai, T. [Department of Neurosurgery, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo (Japan); Kumada, H.; Okumura, T.; Mizumoto, M.; Tsuboi, K. [Department of Radiation Oncology, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan); Zaboronok, A.; Ishikawa, E.; Aiyama, H.; Endo, K.; Takada, T.; Yoshida, F.; Shibata, Y.; Matsumura, A. [Department of Neurosurgery, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai 1-1-1, Tsukuba (Japan)

    2011-12-15

    The phase II trial has been prepared to assess the effectiveness of BPA (250 mg/kg)-based NCT combined with X-ray irradiation and temozolomide (75 mg/m{sup 2}) for the treatment of newly diagnosed GBM. BPA uptake is determined by {sup 18}F-BPA-PET and/or {sup 11}C-MET-PET, and a tumor with the lesion to normal ratio of 2 or more is indicated for BNCT. The maximum normal brain point dose prescribed was limited to 13.0 Gy or less. Primary end point is overall survival.

  9. Chronic use of low-dose aspirin is not associated with lower bone mineral density in the general population.

    Science.gov (United States)

    Bonten, T N; de Mutsert, R; Rosendaal, F R; Jukema, J W; van der Bom, J G; de Jongh, R T; den Heijer, M

    2017-10-01

    Low-dose aspirin is the cornerstone of secondary prevention of cardiovascular disease. Previous studies suggested that the use of aspirin is associated with an increased fracture risk. However, there is uncertainty whether this is due to an effect of aspirin on bone mineral density (BMD). Between 2008 and 2012, information on medication use and dual X-ray absorptiometry measured vertebral and femoral BMD of 916 participants was collected in the Netherland Epidemiology of Obesity study. The cross-sectional association between chronic low-dose aspirin use and BMD was estimated using linear regression, controlling for demography, body composition, comorbidity and other medication use which could affect BMD. A subgroup analysis in postmenopausal women (n=329) was conducted. After full adjustment, there was no difference between aspirin users and non-users for vertebral BMD (adjusted mean difference: 0.036 (95% CI -0.027 to 0.100) g/cm 2 ) and femoral BMD (adjusted mean difference: 0.001 (-0.067 to 0.069) g/cm 2 ). Also in the subgroup of postmenopausal women, aspirin use was not associated with lower vertebral (adjusted mean difference: 0.069 (-0.046 to 0.184) g/cm 2 ) or femoral BMD (adjusted mean difference: -0.055 (-0.139;0.029) g/cm 2 ). Chronic use of low-dose aspirin is not associated with lower BMD in the general population. The increased risk of fractures observed in aspirin users in previous studies is therefore more likely to be the result of common causes of aspirin use and fractures, but not of direct effects of aspirin on BMD. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  10. A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice.

    Science.gov (United States)

    Bilkei-Gorzo, Andras; Albayram, Onder; Draffehn, Astrid; Michel, Kerstin; Piyanova, Anastasia; Oppenheimer, Hannah; Dvir-Ginzberg, Mona; Rácz, Ildiko; Ulas, Thomas; Imbeault, Sophie; Bab, Itai; Schultze, Joachim L; Zimmer, Andreas

    2017-06-01

    The balance between detrimental, pro-aging, often stochastic processes and counteracting homeostatic mechanisms largely determines the progression of aging. There is substantial evidence suggesting that the endocannabinoid system (ECS) is part of the latter system because it modulates the physiological processes underlying aging. The activity of the ECS declines during aging, as CB1 receptor expression and coupling to G proteins are reduced in the brain tissues of older animals and the levels of the major endocannabinoid 2-arachidonoylglycerol (2-AG) are lower. However, a direct link between endocannabinoid tone and aging symptoms has not been demonstrated. Here we show that a low dose of Δ 9 -tetrahydrocannabinol (THC) reversed the age-related decline in cognitive performance of mice aged 12 and 18 months. This behavioral effect was accompanied by enhanced expression of synaptic marker proteins and increased hippocampal spine density. THC treatment restored hippocampal gene transcription patterns such that the expression profiles of THC-treated mice aged 12 months closely resembled those of THC-free animals aged 2 months. The transcriptional effects of THC were critically dependent on glutamatergic CB1 receptors and histone acetylation, as their inhibition blocked the beneficial effects of THC. Thus, restoration of CB1 signaling in old individuals could be an effective strategy to treat age-related cognitive impairments.

  11. Comparison of a low dose polyethylene glycol electrolyte solution with lactulose for treatment of chronic constipation

    OpenAIRE

    Attar, A; Lemann, M; Ferguson, A; Halphen, M; Boutron, M; Flourie, B; Alix, E; Salmeron, M; Guillemot, F; Chaussade, S; Menard, A; Moreau, J; Naudin, G; Barthet, M

    1999-01-01

    Background—Polyethylene glycol (PEG) 3350 is a non-absorbable, non-metabolised osmotic agent used in lavage solutions for gut cleansing. 
Aims—To compare the efficacy of PEG and lactulose in chronic constipation. 
Methods—A total of 115 patients with chronic constipation entered a multicentre, randomised, comparative trial. They initially received two sachets containing either PEG (13 g/sachet) or lactulose (10 g/sachet) and were given an option to change the dose to one ...

  12. Production of haploid plant of 'Banpeiyu' pummelo [Citrus maxima (Burm.) Merr.] by pollination with soft X-ray-irradiated pollen

    International Nuclear Information System (INIS)

    Yahata, Masaki; Yasuda, Kiichi; Kunitake, Hisato; Nagasawa, Kohji; Harusaki, Seiichi; Komatsu, Haruki

    2010-01-01

    To induce haploid plants in Citrus maxima (Burm.) Merr. 'Banpeiyu', we evaluated the effect of pollination with soft X-ray-irradiated pollen on fruit set and seed development, and carried out ovule culture. When 'Banpeiyu' pummelo pistils were pollinated with X-ray-irradiated pollen of 'Fukuhara' sweet orange [C. sinensis (L.) Osbeck], the exposure doses affected the fruit set. The number of seeds per fruit was also affected by the exposure dose, and tended to decrease as the dose increased; however, all developed seeds obtained from these crosses were diploid. In the ovule culture of 'Banpeiyu' pummelo, six embryoids shown haploidy were obtained in all treatments. One haploid plantlet with 9 chromosomes was regenerated from an embryoid in a culture of ovules established 40 days after pollination with 400 Gray (Gy)-irradiated pollen of 'Tosa-buntan' pummelo (C. maxima). This haploid was suggested to be derived from 'Banpeiyu' pummelo by random amplified polymorphic DNA (RAPD) and cleaved amplified polymorphic sequence (CAPS) analysis. (author)

  13. The increase of metallothionein content in rat liver induced by x-ray irradiation and its physiological function

    International Nuclear Information System (INIS)

    Shiraishi, Noriyuki; Miyahara, Masanobu; Utsumi, Kozo; Aono, Kaname; Inoue, Bunji.

    1982-01-01

    Whether or not stress promotes peroxidase reaction of lipids in vivo influences the biosynthesis of metallothionein (MT) was studied. After X-ray irradiation rats were exposed to oxygen, and the liver supernatant was examined. The Zn distribution in the liver supernatant fraction of 10,000 in molecular weight, which was attributed to MT in origin, was small in the control group, but was great in the stress group. The amount of Cd found to the 10,000 fraction (Zn in MT is relatively easily replaced by Cd) was extremely smaller in the control group than in the stress group. These data indicate that the amount of Zn is small, with no appreciable presence of MT, in the 10,000 fraction of the control group. The X-ray irradiated group showed a marked increase of Zn 5 and 7 days later, indicating a definite increase of MT, and the group exposed to O 2 showed similar phenomena, suggesting induction of MT synthesis in the rat liver. (Chiba, N.)

  14. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, Akihisa

    2002-01-01

    We investigated whether chronic irradiation at a low dose-rate interferes with the p53-centered signal transduction pathyway induced by radiation in human cultured cells and C57BL/6N mice. In in vitro experiments, we found that a challenge with X-ray irradiation immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge alone in glioblastoma cells (A-172). In addition, the levels of p53-centered apoptosis and its related proteins after the challenge were strongly correlated with the above-mentioned phenomena in squamous cell carcinoma cells (SAS/neo). In in vivo experiments, the accumulation of p53 and Bax, and the induction of apoptosis were observed dose-dependently in mouse spleen at 12 h after a challenge with X-rays (3.0 Gy). However, we found significant suppression of p53 and Bax accumulation and the induction of apoptosis 12 h after challenge irradiation at 3.0 Gy with a high doses-rate following chronic pre-irradiation (1.5 Gy, 0.001 Gy/min). These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced signaling and/or p53 stability. (author)

  15. Cancer and non-cancer brain and eye effects of chronic low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    Picano, Eugenio; Vano, Eliseo; Domenici, Luciano; Bottai, Matteo; Thierry-Chef, Isabelle

    2012-01-01

    According to a fundamental law of radiobiology (“Law of Bergonié and Tribondeau”, 1906), the brain is a paradigm of a highly differentiated organ with low mitotic activity, and is thus radio-resistant. This assumption has been challenged by recent evidence discussed in the present review. Ionizing radiation is an established environmental cause of brain cancer. Although direct evidence is lacking in contemporary fluoroscopy due to obvious sample size limitation, limited follow-up time and lack of focused research, anecdotal reports of clusters have appeared in the literature, raising the suspicion that brain cancer may be a professional disease of interventional cardiologists. In addition, although terminally differentiated neurons have reduced or mild proliferative capacity, and are therefore not regarded as critical radiation targets, adult neurogenesis occurs in the dentate gyrus of the hippocampus and the olfactory bulb, and is important for mood, learning/memory and normal olfactory function, whose impairment is a recognized early biomarker of neurodegenerative diseases. The head doses involved in radiotherapy are high, usually above 2 Sv, whereas the low-dose range of professional exposure typically involves lifetime cumulative whole-body exposure in the low-dose range of < 200 mSv, but with head exposure which may (in absence of protection) arrive at a head equivalent dose of 1 to 3 Sv after a professional lifetime (corresponding to a brain equivalent dose around 500 mSv). At this point, a systematic assessment of brain (cancer and non-cancer) effects of chronic low-dose radiation exposure in interventional cardiologists and staff is needed

  16. Determination of metal balance shift induced in small fresh water fish by X-ray irradiation using PIXE analysis

    International Nuclear Information System (INIS)

    Yukawa, M.; Aoki, K.; Iso, H.; Kodama, K.; Imaseki, H.; Ishikawa, Y.

    2005-01-01

    In the environmental pollution studies, it is very important to detect not only pollutants but also changes induced in organisms in the environment with various environmental stresses such as heavy metal toxicity radiation and agricultural chemicals. In the latter, monitoring is carried out using biological indicators to find out the changes, which have wide spectra from visible like deformity of the body to invisible such as changes in some enzyme activities. Changes of the balance of essential elements could occur in organisms to deal with the stresses. If we detect an elemental balance shift, we may see the environmental pollution in its early stages. Moreover, in the actual environment, combined effects, additive or reductive with coexistent elements or other stresses, is an important subject for investigation. Therefore, measurement of many elements in the biological indicator's simultaneously and determination of the distribution in the organisms are useful in clarifying the action of pollutants at sublethal levels. A small fresh water fish, Medaka can be used as one of the biological-indicators for determination of water quality. In the National Institute of Radiological Sciences (NIRS), an inbred strain of Medaka Orizias laptipes was established and has been maintained for the research purposes. Since the genetic background of inbred animals is almost uniform, the individual deviation among animals is very small. This characteristic is very useful to investigate the physiological effects of environmental stresses. We have continued to investigate the balance shift of essential elements induced in the bodies of Medaka by several stresses. In this paper, elemental content in various organs of the X-ray irradiated fish determined by PIXE method are reported in comparison with that of the control fish to observe the effect of the X-rays. Body size of Medaka is about 3 cm long, and the internal organs are very small (about l mm on average). PIXE is the most

  17. Low dose chronic Schistosoma mansoni infection increases susceptibility to Mycobacterium bovis BCG infection in mice

    DEFF Research Database (Denmark)

    Elias, D; Akuffo, H; Thors, C

    2005-01-01

    The incidence of mycobacterial diseases is high and the efficacy of Bacillus Calmette Guerin (BCG) is low in most areas of the world where chronic worm infections are common. However, if and how concurrent worm infections could affect immunity to mycobacterial infections has not been elucidated. ...

  18. Blood pressure response to conventional and low-dose enalapril in chronic renal failure

    DEFF Research Database (Denmark)

    Elung-Jensen, Thomas; Heisterberg, Jens; Kamper, Anne-Lise

    2003-01-01

    AIMS: In chronic renal failure, the clearance of most ACE inhibitors including enalapril is reduced. Hence, with conventional dosage, plasma enalaprilat may be markedly elevated. It is unclear whether this excess of drug exposure affords an improved control of blood pressure. The aim of the present...... study was to evaluate short-term blood pressure response to two different plasma levels of enalaprilat. METHODS: As part of an open, randomized, controlled trial of the effect of high and low dosage of enalapril on the progression of renal failure, short-term blood pressure response was evaluated. Data...... potassium concentrations at day 90 and patients in the low group experienced a slight increase in GFR. CONCLUSIONS: In moderate to severe chronic renal insufficiency the same degree of blood pressure control was achieved on low as well as moderate daily doses of enalapril. This was irrespective...

  19. Down-regulation of SMT3A gene expression in association with DNA synthesis induction after X-ray irradiation in nevoid basal cell carcinoma syndrome (NBCCS) cells

    International Nuclear Information System (INIS)

    Sugaya, Shigeru; Nakanishi, Hiroshi; Tanzawa, Hideki; Sugita, Katsuo; Kita, Kazuko; Suzuki, Nobuo

    2005-01-01

    Fibroblast cells derived from nevoid basal carcinoma syndrome (NBCCS) patients show increased levels of DNA synthesis after X-ray irradiation. Genes, whose expression is modulated in association with the DNA synthesis induction, were searched by using PCR-based mRNA differential display analysis in one of the NBCCS cell lines, NBCCS1 cells. Decreased levels of SMT3A gene expression were found in X-ray-irradiated NBCCS1 cells. This decrease was also shown by RT-PCR analysis in another cell line, NBCCS3 cells. In addition to NBCCS cells, normal fibroblast cells showed the DNA synthesis induction after X-ray irradiation when they were treated with antisense oligonucleotides (AO) for SMT3A. However, treatment of normal fibroblasts with the random oligonucleotides (RO) resulted in decreased levels of DNA synthesis after X-ray irradiation. Thus, down-regulation of SMT3A gene expression may be involved in the DNA synthesis induction after X-ray irradiation in the NBCCS cells at least tested

  20. Down-regulation of SMT3A gene expression in association with DNA synthesis induction after X-ray irradiation in nevoid basal cell carcinoma syndrome (NBCCS) cells

    Energy Technology Data Exchange (ETDEWEB)

    Sugaya, Shigeru [Department of Environmental Biochemistry, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Nakanishi, Hiroshi [Department of Clinical Molecular Biology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Tanzawa, Hideki [Department of Clinical Molecular Biology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Sugita, Katsuo [Department of Clinical Medicine, Faculty of Education, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522 (Japan); Kita, Kazuko [Department of Environmental Biochemistry, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan); Suzuki, Nobuo [Department of Environmental Biochemistry, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670 (Japan)]. E-mail: nobuo@faculty.chiba-u.jp

    2005-10-15

    Fibroblast cells derived from nevoid basal carcinoma syndrome (NBCCS) patients show increased levels of DNA synthesis after X-ray irradiation. Genes, whose expression is modulated in association with the DNA synthesis induction, were searched by using PCR-based mRNA differential display analysis in one of the NBCCS cell lines, NBCCS1 cells. Decreased levels of SMT3A gene expression were found in X-ray-irradiated NBCCS1 cells. This decrease was also shown by RT-PCR analysis in another cell line, NBCCS3 cells. In addition to NBCCS cells, normal fibroblast cells showed the DNA synthesis induction after X-ray irradiation when they were treated with antisense oligonucleotides (AO) for SMT3A. However, treatment of normal fibroblasts with the random oligonucleotides (RO) resulted in decreased levels of DNA synthesis after X-ray irradiation. Thus, down-regulation of SMT3A gene expression may be involved in the DNA synthesis induction after X-ray irradiation in the NBCCS cells at least tested.

  1. Combination of BMP-2-releasing gelatin/β-TCP sponges with autologous bone marrow for bone regeneration of X-ray-irradiated rabbit ulnar defects.

    Science.gov (United States)

    Yamamoto, Masaya; Hokugo, Akishige; Takahashi, Yoshitake; Nakano, Takayoshi; Hiraoka, Masahiro; Tabata, Yasuhiko

    2015-07-01

    The objective of this study is to evaluate the feasibility of gelatin sponges incorporating β-tricalcium phosphate (β-TCP) granules (gelatin/β-TCP sponges) to enhance bone regeneration at a segmental ulnar defect of rabbits with X-ray irradiation. After X-ray irradiation of the ulnar bone, segmental critical-sized defects of 20-mm length were created, and bone morphogenetic protein-2 (BMP-2)-releasing gelatin/β-TCP sponges with or without autologous bone marrow were applied to the defects to evaluate bone regeneration. Both gelatin/β-TCP sponges containing autologous bone marrow and BMP-2-releasing sponges enhanced bone regeneration at the ulna defect to a significantly greater extent than the empty sponges (control). However, in the X-ray-irradiated bone, the bone regeneration either by autologous bone marrow or BMP-2 was inhibited. When combined with autologous bone marrow, the BMP-2 exhibited significantly high osteoinductivity, irrespective of the X-ray irradiation. The bone mineral content at the ulna defect was similar to that of the intact bone. It is concluded that the combination of bone marrow with the BMP-2-releasing gelatin/β-TCP sponge is a promising technique to induce bone regeneration at segmental bone defects after X-ray irradiation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Blood pressure response to conventional and low-dose enalapril in chronic renal failure

    DEFF Research Database (Denmark)

    Elung-Jensen, Thomas; Heisterberg, Jens; Kamper, Anne-Lise

    2003-01-01

    AIMS: In chronic renal failure, the clearance of most ACE inhibitors including enalapril is reduced. Hence, with conventional dosage, plasma enalaprilat may be markedly elevated. It is unclear whether this excess of drug exposure affords an improved control of blood pressure. The aim of the present...... study was to evaluate short-term blood pressure response to two different plasma levels of enalaprilat. METHODS: As part of an open, randomized, controlled trial of the effect of high and low dosage of enalapril on the progression of renal failure, short-term blood pressure response was evaluated. Data...

  3. MDMA-assisted psychotherapy using low doses in a small sample of women with chronic posttraumatic stress disorder.

    Science.gov (United States)

    Bouso, José Carlos; Doblin, Rick; Farré, Magí; Alcázar, Miguel Angel; Gómez-Jarabo, Gregorio

    2008-09-01

    The purpose of this study was to investigate the safety of different doses of MDMA-assisted psychotherapy administered in a psychotherapeutic setting to women with chronic PTSD secondary to a sexual assault, and also to obtain preliminary data regarding efficacy. Although this study was originally planned to include 29 subjects, political pressures led to the closing of the study before it could be finished, at which time only six subjects had been treated. Preliminary results from those six subjects are presented here. We found that low doses of MDMA (between 50 and 75 mg) were both psychologically and physiologically safe for all the subjects. Future studies in larger samples and using larger doses are needed in order to further clarify the safety and efficacy of MDMA in the clinical setting in subjects with PTSD.

  4. Low-dose intravenous ketamine for postcardiac surgery pain: Effect on opioid consumption and the incidence of chronic pain.

    Science.gov (United States)

    Cogan, Jennifer; Lalumière, Geneviève; Vargas-Schaffer, Grisell; Deschamps, Alain; Yegin, Zeynep

    2017-01-01

    Recent meta-analyses have concluded that low-dose intravenous ketamine infusions (LDKIs) during the postoperative period may help to decrease acute and chronic postoperative pain after major surgery. This study aims to evaluate the level of pain at least 3 months after surgery for patients treated with a postoperative LDKI versus patients who were not treated with a postoperative LDKI. Administrative and Ethics Board approval were obtained for this study. We performed a retrospective chart review for all patients receiving LDKI, and equal number of age-, sex-, and surgery-matched patients who did not receive LDKI. Low-dose ketamine was prepared using 100 mg of ketamine in 100 ml of normal saline and run between 50 and 200 mcg/kg/h. We reviewed 115 patients with LDKI and 115 without LDKI. The average age was 63.1 years, 73% of the patients were men and sex was evenly distributed between LDKI and non-LDKI. The average duration of the ketamine infusions was 26.8 h with the average dose being 169.9 mg. At an average of 9 months after surgery, 42% of the ketamine group and 38% of the nonketamine group stated that they had had pain on discharge. Of these patients, 30% of the ketamine group and 26% of the nonketamine group still had pain at the time of the phone call. Women in both groups had more acute and chronic pain than men. These results show that LDKI does not promote a decrease in long-term postoperative pain.

  5. Augmentation of natural cytotoxicity by chronic low-dose ionizing radiation in murine natural killer cells primed by IL-2

    International Nuclear Information System (INIS)

    Sonn, Chung-Hee; Choi, Jong-Rip; Kim, Tae-Jin

    2012-01-01

    The possible beneficial effects of chronic low-dose irradiation (LDR) and its mechanism of action in a variety of pathophysiological processes such as cancer are a subject of intense investigation. While animal studies involving long-term exposure to LDR have yielded encouraging results, the influence of LDR at the cellular level has been less well defined. We reasoned that since natural killer (NK) cells constitute an early responder to exogenous stress, NK cells may reveal sentinel alterations in function upon exposure to LDR. When purified NK cells received LDR at 4.2 mGy/h for a total of 0.2 Gy in vitro, no significant difference in cell viability was observed. Likewise, no functional changes were detected in LDR-exposed NK cells, demonstrating that LDR alone was insufficient to generate changes at the cellular level. Nonetheless, significant augmentation of cytotoxic, but not proliferative, function was detected when NK cells were stimulated with low-dose IL-2 prior to irradiation. This enhancement of NK cytotoxicity was not due to alterations in NK-activating receptors, NK1.1, NKG2D, CD69 and 2B4, or changes in the rate of early or late apoptosis. Therefore, LDR, in the presence of suboptimal cytokine levels, can facilitate anti-tumor cytotoxicity of NK cells without influencing cellular proliferation or apoptosis. Whether these results translate to in vivo consequences remains to be seen; however, our data provide initial evidence that exposure to LDR can lead to subtle immune-enhancing effects on NK cells and may explain, in part, the functional basis underlying, diverse beneficial effects seen in the animals chronically exposed to LDR. (author)

  6. Morbidity rate of nervous system among medical personnel occupationally exposed to chronic low dose irradiation

    International Nuclear Information System (INIS)

    Jonkova, A.

    1987-01-01

    The morbidity rate of the nervous system among 1190 subjects, medical personnel, working with sources and environment of ionizing radiation was studied by the personal analysis of the diseases, written down in the personal out-patient department cards as well as of a control group of 870 medical workers of various other specialities. The morbidity rate of the nervous system among the medical personnel, exposed to chronic occupational radiation effect, was established not to be higher than that of the other medical workers - 38.0 and 40.3% respectively. Neuroses and peripheral nervous diseases have the greatest relative share in the structure of morbidity rate of the nervous system in both groups examined, with no statistical significance in the differences of the indices. The significantly higher incidence of autonome dystonias, established among the personnel from the X-ray departments and consulting rooms could be discussed in connection with the great relative share of the subjects from that group with a length of service over 15 years and had received the possible maximum cumulative equivalent doses. 3 tabs., 21 refs

  7. The performance of the anthraquinone/p-Si and the pyridine/p-Si rectifying device under X-ray irradiation

    International Nuclear Information System (INIS)

    Şahin, Yılmaz; Aydoğan, Şakir; Ekinci, Duygu; Turut, Abdulmecit

    2016-01-01

    Some X-ray irradiation-induced electrical characteristics of the Au/anthraquinone/p-Si and the Au/pyridine/p-Si junction devices have been investigated. The experimental ideality factors increased for both devices with increasing irradiation dose from 25 Gy to 150 Gy. These values ranged from 1.10 to 1.52 for Au/anthraquinone/p-Si and from 1.46 to 1.77 for Au/pyridine/p-Si, respectively. Furthermore, the barrier height of Au/anthraquinone/p-Si increased with increasing irradiation dose from 0.75 to 0.91 eV, whereas it displayed about a constant value for Au/pyridine/p-Si. In addition, the series resistance of both devices increased with x-ray dose too. The increase in the series resistance with x-ray irradiation has been attributed to the decrease in the active dopant densities. It was seen that the ionization damage is effective on most of the junction characteristics. The leakage current of the Au/anthraquinone/p-Si device decreased with x-ray irradiation since the irradiation induced the formation of electron-hole pairs and hydroquinone structure, and thus some of them are trapped by the interface states. The degradation of the I-V curves of Au/pyridine/p-Si/Al device is attributed to the variation of the surface or interface states distribution for the devices. The reverse and forward bias currents relatively increased after x-ray irradiation because of the decrease in bulk lifetime. In addition, ATR-FTIR spectra of anthraquinone and pyridine films showed that pyridine is more stable than anthraquinone under x-ray irradiation. - Highlights: • Two junction devices based on organic materials were fabricated. • The effect of the x-ray irradiation on devices were examined. • Both devices showed x-irradiation-dependence.

  8. The performance of the anthraquinone/p-Si and the pyridine/p-Si rectifying device under X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Yılmaz [Department of Physics, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Aydoğan, Şakir, E-mail: saydogan@atauni.edu.tr [Department of Physics, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Ekinci, Duygu [Department of Chemistry, Faculty of Sciences, University of Atatürk, 25240 Erzurum (Turkey); Turut, Abdulmecit [Department of Engineering Physics, Faculty of Sciences, Istanbul Medeniyet University (Turkey)

    2016-11-01

    Some X-ray irradiation-induced electrical characteristics of the Au/anthraquinone/p-Si and the Au/pyridine/p-Si junction devices have been investigated. The experimental ideality factors increased for both devices with increasing irradiation dose from 25 Gy to 150 Gy. These values ranged from 1.10 to 1.52 for Au/anthraquinone/p-Si and from 1.46 to 1.77 for Au/pyridine/p-Si, respectively. Furthermore, the barrier height of Au/anthraquinone/p-Si increased with increasing irradiation dose from 0.75 to 0.91 eV, whereas it displayed about a constant value for Au/pyridine/p-Si. In addition, the series resistance of both devices increased with x-ray dose too. The increase in the series resistance with x-ray irradiation has been attributed to the decrease in the active dopant densities. It was seen that the ionization damage is effective on most of the junction characteristics. The leakage current of the Au/anthraquinone/p-Si device decreased with x-ray irradiation since the irradiation induced the formation of electron-hole pairs and hydroquinone structure, and thus some of them are trapped by the interface states. The degradation of the I-V curves of Au/pyridine/p-Si/Al device is attributed to the variation of the surface or interface states distribution for the devices. The reverse and forward bias currents relatively increased after x-ray irradiation because of the decrease in bulk lifetime. In addition, ATR-FTIR spectra of anthraquinone and pyridine films showed that pyridine is more stable than anthraquinone under x-ray irradiation. - Highlights: • Two junction devices based on organic materials were fabricated. • The effect of the x-ray irradiation on devices were examined. • Both devices showed x-irradiation-dependence.

  9. Study on the effect of x-ray irradiation of seed on zinc uptake in maize (Zea Mays L.) plants

    International Nuclear Information System (INIS)

    Joshi, Gargi; Singh, K.P.; Joshi, G.C.

    2007-01-01

    The effects of irradiations by X-rays at the two dose levels (1.1 KR and 2.2 KR) of seeds on uptake of zinc ion in maize (Zea Mays L.) plants were studied. The uptake and internal distribution of zinc ion in the maize plants was carried out by incorporating radioactive zinc as zinc chloride (ZnCl 2 ) in the nutrient solution to the plants. The localization and translocation of radioactive zinc was studied employing phosphor imaging systems (FX). The radioactivity measurement has been carried out using solid scintillation counter. It was observed that zinc ions uptake was higher in plants out of 2.2 KR X-rays irradiated seeds. (author)

  10. Scintillation properties and X-ray irradiation hardness of Ce3+-doped Gd2O3-based scintillation glass

    International Nuclear Information System (INIS)

    Liu, Liwan; Shao, Chongyun; Zhang, Yu; Liao, Xili; Yang, Qiuhong; Hu, Lili; Chen, Danping

    2016-01-01

    Ce 3+ -doped Gd 2 O 3 -based scintillation glasses are prepared within an air or CO atmosphere. The effects of fluorine, lutetium, barium, and the melting atmosphere on the optical properties, scintillation properties and irradiation hardness are studied. Absorption spectra, luminescence spectra under UV and X-ray excitation, and the X-ray radiation-induced spectra are presented. The results show that the density can be increased by doping with fluorine, lutetium and barium. The luminescence intensity decreases after X-ray irradiation. Because of charge transfer quenching, fluorine and lutetium enhance the UV-excited and X-ray excited luminescence intensity, but barium decreases. Moreover, fluorine and lutetium are advantageous to irradiation hardness while barium is not. In addition, a non-reducing atmosphere provides a higher irradiation hardness than a reducing atmosphere. Fluorine-doped glass is promising to enhance luminescence intensity, promote irradiation hardness, and increase the density.

  11. Investigation of the yield process by deformation luminescence of X-ray irradiated KCl:Ca2+

    International Nuclear Information System (INIS)

    Nakamura, S.; Ida, K.; Ohgaku, T.

    2011-01-01

    It is found that deformation luminescence gives us information about the microscopic yield process of X-ray irradiated KCl:Ca 2+ . The stress-strain curve has a macroscopic yield point. But we find that luminescence appears to start before the macroscopic yield. This means that dislocation begin to move before the macroscopic yield because deformation luminescence is attributed to radiation-induced dislocation motion. The beginning of luminescence is considered to be the microscopic yield. Investigating the dependence of microscopic yield stress on strain rate and impurity concentration gives us additional information. The activation volume obtained from the dependence of microscopic yield stress on strain rate is comparable to the value estimated from the concentration of impurity. Then the dislocation starts to move overcoming impurity-vacancy dipoles as obstacles to dislocation motion. The dislocation density starts to increase at the microscopic yield point and then sharply increases to the macroscopic yield.

  12. Application of the autoblood treated by preliminary extracorporeal X-ray irradiation in the therapy of bronchial asthma patients

    International Nuclear Information System (INIS)

    Goguev, N.T.

    1985-01-01

    A therapeutic method including extracorporeal x-ray irradiation of the autoblood of patients with bronchial asthma complicated by cortisone dependence and polyvalent drug intolerance, has been elaborated and clinically tested. The use of this method brings about good short-term results in 90% of cases and good long-term results in 40% of cases (14-38 months). It provides an opportunity to give up corticosteroids in more than 60% of patients and to decrease the hormone dose in the rest of cortisone-dependent patients with bronchial asthma. The above therapeutic method can be used as an independent type of treatment, especially in the presence of polyvalent drug allergy and as an element of multiple modality therapy of bronchial asthma patients. The method was used under in-patient conditions only. No side effects were marked in the course of the clinical trial. To carry out this type of therapy, patients should be thoroughly screened

  13. Charge yield for cobalt-60 and 10-keV x-ray irradiations of MOS devices

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Fleetwood, D.M.; Schwank, J.R.; Hughes, K.L.

    1991-01-01

    In this paper the radiation response of MOS devices exposed to 60 Co and low-energy (∼10 keV) x-ray irradiation is evaluated as a function of electric field during exposure. Improved charge yield estimates are obtained for 60 Co irradiations at fields below 1 MV/cm by matching voltage shifts due to oxide-trap and interface-trap charge to an E -0.55 electric field dependence. Combining these improved charge yield estimates and calculated dose enhancement factors, the relative response of x-ray to 60 Co irradiations is accurately predicted for oxide electric fields from 0.03 MV/cm to 5.0 MV/cm. The ability to predict the relative response of x-ray to 60 Co irradiations should speed acceptance of x-ray testers as a hardness assurance tool

  14. Influence of silver and copper doping on luminescent properties of zinc-phosphate glasses after x-ray irradiation

    Science.gov (United States)

    Murashov, Alexander A.; Sidorov, Alexander I.; Shakhverdov, Teimur A.; Stolyarchuk, Maxim V.

    2017-11-01

    It is shown, experimentally, that in silver- and copper-containing zinc-phosphate glasses, metal molecular clusters are formed during the glass synthesis. X-ray irradiation of these glasses led to the considerable increase of its luminescence in visible spectral range. This effect is caused by the transformation of the charged metal molecular clusters into the neutral state. Luminescence and excitation spectra of the glass, doped with silver and copper simultaneously, change significantly in comparison with the spectra of glasses doped with one metal. The reason for this can be the formation of hybrid AgnCum molecular clusters. The computer simulation of the structure and optical properties of such clusters by the time-dependent density functional theory method is presented. It is shown that the optimal luminescent material for photonics application, in comparison with other studied materials, is glass, containing hybrid molecular clusters.

  15. Effects of X-ray irradiation on the expression of Pokemon gene in human lung adenocarcinoma cell line

    International Nuclear Information System (INIS)

    Liang Xiaofang; Zou Yue; Wang Lu; Jiang Qisheng; Li Fengsheng

    2012-01-01

    Objective: To study the dose and time effects of X-ray radiation on the expression of Pokemon gene and protein in human lung adenocarcinoma cell line A 549 . Methods: A 549 cells was exposed to different doses of X-ray (2, 4, 6 and 8 Gy), and the expression of Pokemon mRNA and protein of the cells was detected by using Quantitative real-time PCR and western-blotting at 2, 4, 8, 12, 24, and 48 h after irradiation. 3-( 4, 5-Dimethylthiazole-2-yl )-2, 5-diphenyltetrazolium bromide was used to detect the proliferation of A 549 cells at 1, 2, 3, 4, and 5 d after 2 Gy X-ray irradiation. The mock treated A 549 cells were used as the control. Results: The expression of Pokemon mRNA trended to decrease after irradiated with 4, 6 and 8 Gy in the earlier period and increased in the later period with statistical difference at the most time points (t =3.40 -154.76, P =0.000 -0.041). The expression of Pokemon protein trended to increase and reached the peak at 8 h after irradiated of 2, 4, 6 and 8 Gy with statistical difference at the most time points (t =4.18 - 89.64, P =0.000 - 0.039). Compared with the control, the proliferation of A 549 cells was significantly inhibited during 3 to 5 d after irradiation of 2 Gy (t =2.34 - 18.19, P =0.000 -0.040). Conclusions: X-ray irradiation may increase the expression of Pokemon mRNA and protein in A 549 cells, which might be correlated with radiation-resistance of A 549 cells. (authors)

  16. Effects of PTEN transfer on cell cycle progression and expression of P27kipl followed by X-ray irradiation

    International Nuclear Information System (INIS)

    Tian Mei; Wu Congmei; Liu Linlin; Piao Chunji; Li Xiuyi

    2007-01-01

    Objective: To investigate the effect of pEgr-hPTEN stable transfer combined with irradiation on the cell cycle progression and the expression of cell cycle kinase inhibitor P27 kipl protein of SHG-44 human glioma cells. Methods: pEgr-hPTEN vector containing the exogenous wild type PTEN gene was transfected into SHG-44 cells under mediation of lipofectamine in vitro, the positive cell clones were selected and amplified by using G418. Western blotting was used to measure the expression of PTEN protein. Transmission electron microscope was adopted to detect the cell ultrastructural changes and flow cytometry was adopted to analysis the changes of cell cycle progression and the expression of P27 kipl in SHG-44-sPTEN cells followed by different doses of X-ray irradiation. Results: Egr-1 promoter could be induced and activated by irradiation and then enhanced the expression of downstream PTEN gene within 5 Gy. The ultrastructure of SHG-44-sPTEN cells had many degenerative changes and many early apoptotic changes including the chromosome condensate around the nuclear envelope. pEgr-hPTEN stable transfer combined with X-ray irradiation could significantly induce G 1 arrest. The expression of P27 kipl proteins increased in SHG-44-sPTEN stable transfected cells. Conclusion: PTEN stable transfer combined with irradiation can significantly induce G 1 arrest. The molecular basis may be correlated with the enhanced expression of PTEN induced by irradiation and increased expression of cell cycle kinase inhibitor P27 kipl . (authors)

  17. Transforming growth factor beta 1 expression and inflammatory cells in tooth extraction socket after X-ray irradiation

    Directory of Open Access Journals (Sweden)

    Ramadhan Hardani Putra

    2016-06-01

    Full Text Available Background: Radiographic examination is often used in dentistry to evaluate tooth extraction complications. X-ray used in radiographic examination, however, has negative effects, including damage to DNA and inflammatory response during wound healing process. Purpose: This study aimed to analyze the effects of X-ray irradiation on transforming growth factor beta 1 (TGF-ß1 expression and number of inflammatory cells in tooth extraction sockets. Method: Thirty rats were divided into three groups, which consist of control group (with a radiation of 0 mSv, treatment group 1 (with a radiation of 0.08 mSv, and treatment group 2 (with a radiation of 0.16 mSv. These rats in each group were sacrificed on days 3 and 5 after treatment. Inflammatory cells which were observed in this research were PMN, macrophages, and lymphocytes. Histopathological and immunohistochemical examinations were used to calculate the number of inflammatory cells and TGF-ß1 expression. Obtained data were analyzed using SPSS 16.0 software with one way ANOVA and Tukey’s HSD tests. Result: There was no significant decrease in the number of PMN. On the other hand, there were significant decreases in the number of macrophages and lymphocytes in the sacrificed group on day-5 with the radiation of 0.16 mSv. Similarly, the most significant decreased expression of TGF-ß1 was found in the group sacrificed on day 5 with the radiation of 0.16 mSv. Conclusion: X-ray irradiation with 0.08 mSv and 0.16 mSv doses can decrease TGF-ß1 expression and number of inflammatory cells in tooth extraction sockets on day 3 and 5 post extraction.

  18. The Management of Patients with Chronic Subdural Hematoma Treated with Low-Dose Acetylsalicylic Acid: An International Survey of Practice.

    Science.gov (United States)

    Soleman, Jehuda; Kamenova, Maria; Guzman, Raphael; Mariani, Luigi

    2017-11-01

    The aim of this international survey was to investigate the current management of patients undergoing surgery for chronic subdural hematoma (cSDH) treated with low-dose acetylsalicylic acid (ASA). We administered a survey via e-mail to neurosurgeons with questions relating to the surgical treatment of cSDH, emphasizing their practices with patients treated with low-dose ASA. We received 157 responses, with a response rate of 22.4%. Almost 80% of the responders discontinue ASA treatment at least 5 days before surgery and 80.7% resume treatment after 5 days or more, and 27.6% discontinue treatment for at least 30 days. The main factor influencing ASA resumption time is the indication for ASA (54.5%), and postoperative imaging is concluded in 71.7%, Postoperative thrombosis prophylaxis is administered by 60% of the responders, and 50% apply it 24 hours after surgery. Almost 95% of the responders believe that better evidence is needed for the management of patients with cSDH treated with ASA. Guidelines for these patients exist in only 24.3% of the institutes. Most neurosurgeons discontinue ASA treatment for at least 7 days in the perioperative period of surgical evacuation of cSDH, even though recent studies show that early ASA resumption might be safe. Thrombosis prophylaxis is administered by only 60%, even though patients with cSDH are at high risk of developing thromboembolic complications. Better evidence and guidelines are warranted because the incidence of patients with cSDH under the treatment of ASA is increasing. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. induction of cytogenetic damage by low doses of acute and chronic gamma-radiation in mammalian and plant cells

    International Nuclear Information System (INIS)

    Zaichkina, S.I.; Aptikaeva, G.F.; Akhmadieva, A.Ch.; Rozanova, O.M.; Smirnova, E.N.; Rogova, N.J.; Ganassi, E.E.

    1997-01-01

    The problem of the biological action of low doses of mutagenic agents has received much attention recently. It is shown that the risk factors for low-dose exposure are greater that it was calculated by extrapolation from higher to lower doses. The aim of the present study was to investigate the effect of low doses on various biological objects including animal and plant cells. (authors)

  20. Induction of cytogenetic damage by low doses of acute and chronic gamma-radiation in mammalian and plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Zaichkina, S.I.; Aptikaeva, G.F.; Akhmadieva, A.Ch.; Rozanova, O.M.; Smirnova, E.N.; Rogova, N.J.; Ganassi, E.E. [Institute of Theoretical and Experimental Biophysics, Moscow (Russian Federation)

    1997-03-01

    The problem of the biological action of low doses of mutagenic agents has received much attention recently. It is shown that the risk factors for low-dose exposure are greater that it was calculated by extrapolation from higher to lower doses. The aim of the present study was to investigate the effect of low doses on various biological objects including animal and plant cells. (authors)

  1. Chronic low-dose γ-irradiation of Drosophila melanogaster larvae induces gene expression changes and enhances locomotive behavior

    International Nuclear Information System (INIS)

    Kim, Cha Soon; Lee, Byung Sub; Lee, In Kyung; Yang, Kwang Hee; Kim, Ji-Young; Nam, Seon Young; Seong, Ki Moon

    2015-01-01

    Although radiation effects have been extensively studied, the biological effects of low-dose radiation (LDR) are controversial. This study investigates LDR-induced alterations in locomotive behavior and gene expression profiles of Drosophila melanogaster. We measured locomotive behavior using larval pupation height and the rapid iterative negative geotaxis (RING) assay after exposure to 0.1 Gy γ-radiation (dose rate of 16.7 mGy/h). We also observed chronic LDR effects on development (pupation and eclosion rates) and longevity (life span). To identify chronic LDR effects on gene expression, we performed whole-genome expression analysis using gene-expression microarrays, and confirmed the results using quantitative real-time PCR. The pupation height of the LDR-treated group at the first larval instar was significantly higher (∼2-fold increase in PHI value, P < 0.05). The locomotive behavior of LDR-treated male flies (∼3 − 5 weeks of age) was significantly increased by 7.7%, 29% and 138%, respectively (P < 0.01), but pupation and eclosion rates and life spans were not significantly altered. Genome-wide expression analysis identified 344 genes that were differentially expressed in irradiated larvae compared with in control larvae. We identified several genes belonging to larval behavior functional groups such as locomotion (1.1%), oxidation reduction (8.0%), and genes involved in conventional functional groups modulated by irradiation such as defense response (4.9%), and sensory and perception (2.5%). Four candidate genes were confirmed as differentially expressed genes in irradiated larvae using qRT-PCR (>2-fold change). These data suggest that LDR stimulates locomotion-related genes, and these genes can be used as potential markers for LDR. (author)

  2. Experimental study on carcinoma of the stomach in rats induced by administration of N-methyl-N'-nitro-N-nitrosoguanidine and x-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Haizuka, S [Hiroshima Univ. (Japan).School of Medicine

    1979-12-01

    Induction of gastrointestinal cancer in 109 6-week-old wistar rats (54 males, 55 females) divided into 6 groups was carried out with various combinations of localized x-ray irradiation and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Carcinoma of the glandular part of the stomach and duodenum was found in 50% of the rats in group 1 (localized x-ray irradiation, 2000 R), in 73.3% in group 2 (80 ..mu..g/ml of MNNG in drinking water), in 52.9% in group 3 (x-ray irradiation, 2000 R; MNNG), in 78% in group 4 (x-ray irradiation + oral MNNG at the same time), and in 72.7% in group 5 (oral MNNG + x-ray irradiation). Group 6 was not treated. Most of the cases of carcinoma developed in the antrum of the glandular part of the stomach. Of the histological types of carcinoma, very differentiated tubular adenocarcinoma was the most frequent. Sarcoma of the glandular part of the stomach, which was frequently complicated by carcinoma, was seen in 14.2% of the rats in group 1 and in 45.5% in group 5. Two kinds of adenomatous hyperplasia of the gastroduodenal mucosa were noted in the treated groups. In group 1, only downward adenomatous hyperplasia was seen. In group 2, two kinds of adenomatous hyperplasia were located in the antrum only. In groups 3, 4, and 5, two kinds of adenomatous hyperplasia were found in the antrum and duodenum. Most of the cases of adenomatous hyperplasia were complicated by adenocarcinoma, which frequently results from a downward type of adenomatous hyperplasia. Intestinal metaplasia of the gastric mucosa occurred often in group 4 (71.4%) and group 5 (72.7%). Squamous metaplasia of the gastric mucosa occurred frequently in the limiting ridge. There was no difference between groups 1 and 2 regarding the incidence of squamous metaplasia (25%) while group 4 showed the highest rate (71.4%).

  3. A Study on the Effects of the X-Ray Irradiation and Thyroid Gland on the Erythropoietic System in Rabbit

    International Nuclear Information System (INIS)

    Kim, Kong Keun

    1967-01-01

    The effects of X-ray irradiation and the thyroid gland on the erythropoietic system were studied in the white male rabbits. The total body irradiation was done in doses of 250r and 500r to each of 5 rabbits for 10 days. The factors were 220 KV, 10 mA, FLI/4 Cu+1 mmAl (HVL:2.0 mmCu) 50 cm F.S.D. The thyroid dysfunction was experimentally induced by giving 2 mg of thyroid tablets per kg body weight for 15 days in 5 rabbits for hyperthyroidism and by giving 1.5 mC of 131 I per kg body weight in another 5 rabbits for hypothyroidism. Fourteen healthy rabbits were used as control. The hematologic changes and ferrokinetic data obtained from 59 Fe and apparent half survival of the red blood cells obtained from 51 Cr were compared. Following were the results: A. X-ray irradiated group; 1) There were no significant changes in hematologic findings except for leucopenia. A slight decrease of red blood cells was observed in 500r irradiated animals. 2) The decrease in the iron turnover rates of the plasma and red blood cells as well as in the red cell renewal rate were found in both groups. A significant decrease of the red cell iron utilization rate was observed in the 500r irradiated animals. 3) The apparent half survival times of the red blood cells were slightly, in the 250r (12.1±0.80 days), and markedly shortened in the 500r irradiated animals (9.8±1.38 days), the normal being 14.0±1.6 days. 4) It appears, therefore, that the anemia caused by X-ray irradiation is due to the inhibition of hemopoietic function and the excess destruction of the red blood cells. B. 1) The slight increase of the red blood cell count and circulating blood volume with the normal serum iron level were observed in the hyperthyoid group, while the decrease of the red and white blood cell counts, hemoglobin and hematocrit values with a marked decrease of the serum iron level in the hypothyroid group. 2) A marked decrease of the plasma iron disappearance rate with increase of plasma iron turnover

  4. Chronic dietary exposure to a low-dose mixture of genistein and vinclozolin modifies the reproductive axis, testis transcriptome, and fertility.

    Science.gov (United States)

    Eustache, Florence; Mondon, Françoise; Canivenc-Lavier, Marie Chantal; Lesaffre, Corinne; Fulla, Yvonne; Berges, Raymond; Cravedi, Jean Pierre; Vaiman, Daniel; Auger, Jacques

    2009-08-01

    The reproductive consequences and mechanisms of action of chronic exposure to low-dose endocrine disruptors are poorly understood. We assessed the effects of a continuous, low-dose exposure to a phytoestrogen (genistein) and/or an antiandrogenic food contaminant (vinclozolin) on the male reproductive tract and fertility. Male rats were exposed by gavage to genistein and vinclozolin from conception to adulthood, alone or in combination, at low doses (1 mg/kg/day) or higher doses (10 and 30 mg/kg/day). We studied a number of standard reproductive toxicology end points and also assessed testicular mRNA expression profiles using long-oligonucleotide microarrays. The low-dose mixture and high-dose vinclozolin produced the most significant alterations in adults: decreased sperm counts, reduced sperm motion parameters, decreased litter sizes, and increased post implantation loss. Testicular mRNA expression profiles for these exposure conditions were strongly correlated. Functional clustering indicated that many of the genes induced belong to the "neuroactive ligand-receptor interactions" family encompassing several hormonally related actors (e.g., follicle-stimulating hormone and its receptor). All exposure conditions decreased the levels of mRNAs involved in ribosome function, indicating probable decreased protein production. Our study shows that chronic exposure to a mixture of a dose of a phytoestrogen equivalent to that in the human diet and a low dose-albeit not environmental-of a common anti-androgenic food contaminant may seriously affect the male reproductive tract and fertility.

  5. Randomized study on hydroxyurea alone versus hydroxyurea combined with low-dose interferon-alpha 2b for chronic myeloid leukemia

    NARCIS (Netherlands)

    Kluin-Nelemans, JC; Delannoy, A; Louwagie, A; Le Cessie, S; Hermans, J; van der Burgh, JF; Hagemeijer, AM; Van den Berghe, H

    1998-01-01

    Interferon-alpha (IFN-alpha) is considered the standard therapy for chronic myeloid leukemia (CML) patients not suitable for allogeneic stem cell transplantation. From 1987 through 1992, 195 patients in the Benelux with recent untreated CML were randomized between low-dose IFN-alpha 2b (3 MIU, 5

  6. Chronic low-dose-rate ionising radiation affects the hippocampal phosphoproteome in the ApoE-/- Alzheimer's mouse model

    DEFF Research Database (Denmark)

    Kempf, S. J.; Janik, Dirk; Barjaktarovic, Zarko

    2016-01-01

    Accruing data indicate that radiation-induced consequences resemble pathologies of neurodegenerative diseases such as Alzheimer's. The aim of this study was to elucidate the effect on hippocampus of chronic low-dose-rate radiation exposure (1 mGy/day or 20 mGy/day) given over 300 days with cumula...

  7. Saffron extracts effect on processes in brain structures under exposure to x-ray irradiation of medium dose

    International Nuclear Information System (INIS)

    Rzaeva, A.

    2012-01-01

    Full text : Process of ionizing radiation on live organism is accompanied by interaction of free radicals (FR) with molecules of proteins, nucleic acids and lipids. In its turn, FR occurs subsequently by excitation and ionization of molecules. Besides all, ionizing radiation becomes the reason of accumulation in body tissues of toxic products (radio toxic) that strengthen beam effect. Endogenous antioxidatic system (EAS) of an organism plays a significant role in detoxication of redundant quantity of FR formed in cells. Ionizing radiation influences negatively to high-grade functioning of basic EAS enzymes. Besides, during radiation injuries, the level of FR increases. In case of its exhaustion and lack insertion of natural antioxidants (bioantioxidants) to organism plays a therapeutic role. Thus, in our work we used saffron extract in experiments with the purpose of studying its effect on the activity of antioxidant enzymes at radiation influence. Determination of proteins has been carried out with Lowry method. In the result of carried-out researches, it has been detected fixed dynamics of activity change of antioxidant enzymes in various brain structures of white rats within x-ray irradiation at medium dose, and joint impact of x-ray radiation of saffron extract. Under exposure to X-ray irradiation of medium dose in some brain structures decreasing of catalase activity was revealed. Tendency towards decreasing is more developed on the 3th day of irradiation. As opposed to catalase activity GPO activity was increased. Insertion of saffron extract to experimental animals (for 21 days before irradiation) conducive to prevention the decreasing of catalase activity stabilizes GPO activity and exerts an effective influence. Thereby, bioantioxidants have significant role in the regulation of processes occurred in tissues and cells under the influence of extreme factors. Antioxidant protection system of organism carries out continuous protection of organism from toxic

  8. Treatment of chronic hemodialysis patients with low-dose fenofibrate effectively reduces plasma lipids and affects plasma redox status

    Directory of Open Access Journals (Sweden)

    Makówka Agnieszka

    2012-07-01

    Full Text Available Abstract Dyslipidemia is common in chronic hemodialysis patients and its underlying mechanism is complex. Hemodialysis causes an imbalance between antioxidants and production of reactive oxygen species, which induces the oxidative stress and thereby may lead to accelerated atherosclerosis. Statins have been found to be little effective in end-stage kidney disease and other lipid-lowering therapies have been only scarcely studied. The study aimed to assess the effect of low-dose fenofibrate therapy on plasma lipids and redox status in long-term hemodialysis patients with mild hypertriglyceridemia. Twenty seven chronic hemodialysis patients without any lipid-lowering therapy were included in a double-blind crossover, placebo-controlled study. The patients were randomized into two groups and were given a sequence of either 100 mg of fenofibrate per each hemodialysis day for 4 weeks or placebo with a week-long wash-out period between treatment periods. Plasma lipids, high sensitive C-reactive protein (CRP, urea, creatinine, electrolytes, phosphocreatine kinase (CK, GOT, GPT and plasma thiols (total and free glutathione, homocysteine, cysteine and cysteinylglycine were measured at baseline and after each of the study periods. Plasma aminothiols were measured by reversed phase HPLC with thiol derivatization with 2-chloro-1-methylquinolinium tetrafluoroborate. Fenofibrate therapy caused a significant decrease of total serum cholesterol, LDL cholesterol and triglycerides and an increase of HDL cholesterol. The treatment was well tolerated with no side-effects but there was a small but significant increase of CK not exceeding the upper limit of normal range. There were no changes of serum CRP, potassium, urea, and creatinine and liver enzymes during the treatment. Neither total nor total free cysteinylglycine and cysteine changed during the study but both total and free glutathione increased during the therapy with fenofibrate and the same was observed

  9. Chronic exposure to low doses of pharmaceuticals disturbs the hepatic expression of circadian genes in lean and obese mice

    Energy Technology Data Exchange (ETDEWEB)

    Anthérieu, Sébastien; Le Guillou, Dounia; Coulouarn, Cédric; Begriche, Karima [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Trak-Smayra, Viviane [Pathology Department, Saint-Joseph University, Beirut (Lebanon); Martinais, Sophie [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Porceddu, Mathieu [Mitologics SAS, Hôpital Robert Debré, 48 Boulevard Sérurier, 75019 Paris (France); Robin, Marie-Anne [INSERM, U991, Université de Rennes 1, 35000 Rennes (France); Fromenty, Bernard, E-mail: bernard.fromenty@inserm.fr [INSERM, U991, Université de Rennes 1, 35000 Rennes (France)

    2014-04-01

    Drinking water can be contaminated with pharmaceuticals. However, it is uncertain whether this contamination can be harmful for the liver, especially during obesity. Hence, the goal of our study was to determine whether chronic exposure to low doses of pharmaceuticals could have deleterious effects on livers of lean and obese mice. To this end, lean and ob/ob male mice were treated for 4 months with a mixture of 11 drugs provided in drinking water at concentrations ranging from 10 to 10{sup 6} ng/l. At the end of the treatment, some liver and plasma abnormalities were observed in ob/ob mice treated with the cocktail containing 10{sup 6} ng/l of each drug. For this dosage, a gene expression analysis by microarray showed altered expression of circadian genes (e.g. Bmal1, Dbp, Cry1) in lean and obese mice. RT-qPCR analyses carried out in all groups of animals confirmed that expression of 8 different circadian genes was modified in a dose-dependent manner. For some genes, a significant modification was observed for dosages as low as 10{sup 2}–10{sup 3} ng/l. Drug mixture and obesity presented an additive effect on circadian gene expression. These data were validated in an independent study performed in female mice. Thus, our study showed that chronic exposure to trace pharmaceuticals disturbed hepatic expression of circadian genes, particularly in obese mice. Because some of the 11 drugs can be found in drinking water at such concentrations (e.g. acetaminophen, carbamazepine, ibuprofen) our data could be relevant in environmental toxicology, especially for obese individuals exposed to these contaminants. - Highlights: • The contamination of drinking water with drugs may have harmful effects on health. • Some drugs can be more hepatotoxic in the context of obesity and fatty liver. • Effects of chronic exposure of trace drugs were studied in lean and obese mouse liver. Drugs and obesity present additive effects on circadian gene expression and toxicity. • Trace

  10. Mathematical modeling predicts enhanced growth of X-ray irradiated pigmented fungi.

    Directory of Open Access Journals (Sweden)

    Igor Shuryak

    Full Text Available Ionizing radiation is known for its cytotoxic and mutagenic properties. However, recent evidence suggests that chronic sub-lethal irradiation stimulates the growth of melanin-pigmented (melanized fungi, supporting the hypothesis that interactions between melanin and ionizing photons generate energy useful for fungal growth, and/or regulate growth-promoting genes. There are no quantitative models of how fungal proliferation is affected by ionizing photon energy, dose rate, and presence versus absence of melanin on the same genetic background. Here we present such a model, which we test using experimental data on melanin-modulated radiation-induced proliferation enhancement in the fungus Cryptococcus neoformans, exposed to two different peak energies (150 and 320 kVp over a wide range of X-ray dose rates. Our analysis demonstrates that radiation-induced proliferation enhancement in C. neoformans behaves as a binary "on/off" phenomenon, which is triggered by dose rates 5000 mGy/h. Proliferation enhancement of irradiated cells compared with unirradiated controls occurs at both X-ray peak energies, but its magnitude is modulated by X-ray peak energy and cell melanization. At dose rates <5000 mGy/h, both melanized and non-melanized cells exposed to 150 kVp X-rays, and non-melanized cells exposed to 320 kVp X-rays, all exhibit the same proliferation enhancement: on average, chronic irradiation stimulates each founder cell to produce 100 (95% CI: 83, 116 extra descendants over 48 hours. Interactions between melanin and 320 kVp X-rays result in a significant (2-tailed p-value = 4.8 × 10(-5 additional increase in the number of radiation-induced descendants per founder cell: by 55 (95% CI: 29, 81. These results show that both melanin-dependent and melanin-independent mechanisms are involved in radiation-induced fungal growth enhancement, and implicate direct and/or indirect interactions of melanin with high energy ionizing photons as an important pro

  11. Effects of X-ray irradiation to genetic transformation of Eruca sativa Mill mediated by agrobacterium rhizogenes

    International Nuclear Information System (INIS)

    Wu Zhenhua; Zhang Hong; Liu Bin; Li Ning; Niu Bingtao; Wang Genxuan; Li Sha; Sun Peng

    2008-01-01

    To investigate the effects of X-ray irradiation to the hairy root induction of Eruca sativa Mill, and to provide basic experimental data for concerted reaction of irradiation to the Genetic transformation technology. The aseptic cotyledons of Eruca sativa Mill were jointly treated with the X-ray at dose of 5, 10, 15, 20 Gy respectively and the different infected time, then the influence of explant age, pre-culturing time, dose of X-ray and infected time were studied. Furthermore, the hairy roots were testified in molecular level by the polymerase chain reaction(PCR). The irradiation of X-ray at dose of 15 Gy can improve the frequency of Eruca sativa Mill hairy root induction in a dose-dependent manner. Moreover, the transformation frequency in pre-infection plus irradiation group is higher than that in pre-irradiation plus infection group at the same irradiation dose. In addition, the PCR analysis also demonstrated that rolB gene of T-DNA from Ri plasmid had been integrated into the genome of the transformed roots. The irradiation of X-ray has some positive effects on the hairy root induction of Eruca sativa Mill, and the optimal revulsive dose is 15 Gy ora little bit more. (authors)

  12. Effects of X-ray irradiation on expression of Pokemon gene in A549 cells of human lung adenocarcinoma

    International Nuclear Information System (INIS)

    Wang Lu; Zou Yue; Jiang Qisheng; Li Wei; Song Xiujun; Zhou Xiangyan; Wang Cuilan

    2011-01-01

    Objective: To study the dose-and time-effects of X-ray irradiation on the expression of Pokemon gene in A549 cells of human lung adenocarcinoma. Methods: A549 cells were cultured in vitro and exposed to X-rays with the doses of 2, 4, 6 and 8 Gy, respectively. Untreated A549 cells were used as control group. The relative levels of Pokemon mRNA expression in the cells were detected by using quantitative real-time PCR at 2, 4, 8, 12, 24, 48 and 72 h after irradiation. Results: The Pokemon mRNA expression levels decreased in the early period after irradiation (except 2 and 4 h after irradiation in 2 Gy group) and then increased in the later stage (48 h after irradiation) with significant statistical differences at the most time points in comparison with the control group (t=3.40-154.76, P<0.05). Conclusions: Higher doses of X-rays may degrade the expression of Pokemon mRNA in the human A549 cells and induce apoptosis in the early period, hut also may upgrade its expression in the later period, which might be correlated with the cell cycle regulation and DNA damage repair in the A549 cells. (authors)

  13. Effect of x-ray irradiation on maize inbred line B73 tissue cultures and regenerated plants

    International Nuclear Information System (INIS)

    Wang, A.S.; Cheng, D.S.K.; Milcic, J.B.; Yang, T.C.

    1988-01-01

    In order to enhance variation induced by the tissue culture process and to obtain agronomically desirable mutants, friable embryogenic tissue cultures of maize (Zea mays L.) inbred line B73 were x-ray irradiated with 11 doses [0-8.4 kilorads (kR)]. Reductions in callus growth rate and embryogenic callus formation occurred with increasing x-ray doses 20 d and 3 months after irradiation. Callus irradiated with 0.8 kR showed a significant increase in growth rate and a 20% increase in embryogenic callus 9 months after irradiation. A total of 230 R 0 plants were regenerated for evaluation. Pollen fertility and seed set of R 0 plants decreased with increasing x-ray dosage. Days to anthesis and plant height of R 0 plants varied among x-ray treatments but were generally reduced with higher dosages. The number of chromosomal aberrations increased with x-ray dosage. The R 1 seeds taken from R 0 plants were also grown and tested for mutant segregation. Plants regenerated from irradiated calli had a two- to 10-fold increase in mutations over plants regenerated from unirradiated control callus. Germination frequency of seeds from R 0 plants decreased with increasing x-ray dosage. Although chlorophyll mutants were most frequently observed, a number of vigorous plants with earlier anthesis date were also recovered

  14. The effect of X-ray irradiation on a red cell component in WB, WRC and LPRC

    International Nuclear Information System (INIS)

    Tayama, Tatsuya; Toyota, Kuroh; Nagahashi, Hisakata; Masuyama, Tetsuya; Haneda, Kenji; Juji, Takeo.

    1990-01-01

    In spite of the use of X-ray irradiation on blood products, few data about its effect on components are reported. We need more informations about a quality of irradiated red cell components. This study shows in vitro changes of irradiated red cell component in WB, WRC and LPRC as the minimum dose of 1,500, 3,000, and 5,000 rads. The fact as follows were observed in response to irradiated doses: 1) increased fragility of red cell membrane, 2) increased amount of plasma K and plasma Hb, and 3) decrease of ATP in WB.2,3-DPG, glucose, pH, Ht and Cl. The numbers of RBC, WBC and Platelet were not affected by irradiation with doses between 1,500 and 5,000 rads. According to these results, the followings are recommended: 1) irradiation with 1,500 rads is a proper method for WB, 2) in order to avoid the risk of increased plasma K, WB should be used within 1 week after irradiation, and WRC and LPRC should be used 24 hours after irradiation. (author)

  15. Influence of x-ray irradiation on the proliferative ability of the germinal layer cells of Echinococcus multilocularis

    International Nuclear Information System (INIS)

    Ohnishi, Kenji

    1986-01-01

    Influence of X-ray irradiation on the proliferative ability of the germinal layer cells of larval Echinococcus multilocularis was studied by using small sterile hydatids containing vesicles composed of a non-cellular laminated layer and a cellular germinal layer. The small sterile hydatids were irradiated by X-ray at dose levels of 5,000, 15,000, 25,000, 35,000, 45,000 or 55,000 R and implanted into the peritoneal cavity of Chinese hamsters. Fully developed hydatids were recognized in all cases irradiated at up to 35,000 R, when assessed 113 days after implantation. At 45,000 R, 2 out of 6 animals showed small, fully developed hydatids. No such hydatid was found in the other 4 animals nor in any of the animals implanted with hydatids irradiated at 55,000 R. No structural differences were observed between fully developed hydatids originating from the irradiated and non-irradiated small hydatids. These results indicate that the tolerance limit of the germinal layer cells is between 45,000 R and 55,000 R. (author)

  16. ROVIBRATIONALLY RESOLVED DIRECT PHOTODISSOCIATION THROUGH THE LYMAN AND WERNER TRANSITIONS OF H2 FOR FUV/X-RAY-IRRADIATED ENVIRONMENTS

    International Nuclear Information System (INIS)

    Gay, C. D.; Porter, R. L.; Stancil, P. C.; Abel, N. P.; Ferland, G. J.; Shaw, G.; Van Hoof, P. A. M.; Williams, R. J. R.

    2012-01-01

    Using ab initio potential curves and dipole transition moments, cross-section calculations were performed for the direct continuum photodissociation of H 2 through the B 1 Σ + u 1 Σ + g (Lyman) and C 1 Π u 1 Σ + g (Werner) transitions. Partial cross-sections were obtained for wavelengths from 100 Å to the dissociation threshold between the upper electronic state and each of the 301 bound rovibrational levels v''J'' within the ground electronic state. The resulting cross-sections are incorporated into three representative classes of interstellar gas models: diffuse clouds, photon-dominated regions, and X-ray-dominated regions (XDRs). The models, which used the CLOUDY plasma/molecular spectra simulation code, demonstrate that direct photodissociation is comparable to fluorescent dissociation (or spontaneous radiative dissociation, the Solomon process) as an H 2 destruction mechanism in intense far-ultraviolet or X-ray-irradiated gas. In particular, changes in H 2 rotational column densities are found to be as large as 20% in the XDR model with the inclusion of direct photodissociation. The photodestruction rate from some high-lying rovibrational levels can be enhanced by pumping from H Lyβ due to a wavelength coincidence with cross-section resonances resulting from quasi-bound levels of the upper electronic states. Given the relatively large size of the photodissociation data set, a strategy is described to create truncated, but reliable, cross-section data consistent with the wavelength resolving power of typical observations.

  17. Changes in regional blood flow of normal and tumor tissues following hyperthermia and combined X-ray irradiation

    International Nuclear Information System (INIS)

    Suga, Kazuyoshi

    1986-01-01

    Hyperthermia and X-ray irradiation were given to Ehrlich tumors, which were induced in the ventrum of the right hind foot of ICR mice, and to the normal tissues. Their effects on regional blood flow were examined using Xe-133 local clearance method. Blood flow of the normal tissues remained unchanged by heating at 41 deg C for 30 minutes, and increased by heating at 43 deg C and 45 deg C for 30 minutes. On the contrary, blood flow of the tumors decreased with an increase in temperature. When hypertermia (43 deg C for 30 minutes) was combined with irradiation of 30 Gy, decrease in blood flow of the tumors was greater than the normal tissues at 24 hours. Blood flow of the tumors depended on tumor size. The decreased amount of blood flow by hyperthermia was more for tumors > 250 mm 3 than tumors 3 . Blood flow ratios of tumor to normal tissues were also smaller in tumors > 250 mm 3 than tumors 3 . In the case of tumors 3 , blood flow tended to return to normal at 3 hr after heating at 43 deg C for 30 min. However, this was not seen in tumors > 250 mm 3 . (Namekawa, K.)

  18. Preventive effect of ganoderma lucidum (Reishi) on the suppression of hematopoietic system by X-ray irradiation

    International Nuclear Information System (INIS)

    Itoh, Hiroko; Nakata, Fukuyoshi; Sasaki, Hiroyuki; Ito, Hitoshi

    2013-01-01

    Reishi has been used for a roborant or the elixir of life from ancient times. In the present study, the preventive effects of Reishi on hematopoietic suppression from X-ray irradiation in mice were investigated. 5.0 Gy-irradiated mice induced the decrease of red blood cell, platelet, white blood cell, granulocytes, the index of spleen and thymus, and the number of spleen cells. Oral administration of Reishi tended to decrease these damage on hematopoiesis, and reticuloendothelial system. Reishi enhanced the degree of spleen cells-mediated sheep red blood cells (SRBC) hemolysis (quantitative hemolysis of SRBC). Reishi augmented the level of erythroid burst-forming cell (BFU-E), and accelerated the recovery of the number of BFU-E in X-irradiated mice, although Reishi did not influence red blood cell counts and colony-forming unit-erythropoetin dependent (CFU-E) number. A significant elevation in the CFU-GM (granulocytes-macrophages) level was observed. Histological examinations revealed that Reishi accerelated the hematopoietic recovery and decrease on damage of spleen and thymus. (author)

  19. The nuclear pore density in rat liver cells upon regeneration and total body X-ray irradiation

    International Nuclear Information System (INIS)

    Kuz'mina, S.N.; Troitskaya, L.P.; Mirkhamidova, P.A.; Bul'dyaeva, T.V.; Zbarskij, I.B.; Grigor'ev, V.B.; Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Virusologii)

    1979-01-01

    The nuclear pore density has been investigated in rat liver cells in the course of regeneration and X-ray irradiation. It has been found that the number of pore complexes (PC) per nuclear shell (NS) unit area in the liver cells is not constant. In an hour following whole-body irradiation of rats with a regenerating liver at the 1200 R dose the number of PC per 1 μm 2 of the nuclear shell area decreases by 5, 8 times as compared with the PC density in the regenerating liver cells of the irradiated rats, the PC degradation and structural rupture being observed. It has been established by means of the freezing-etching method which enables PC surfaces observation as for cytoplasma as well as for nucleoplasma that the PC peripheral granulas and the central granula consist of subparticles being approximately of the same size. The central granula forms a channel through which the material containing RNA passes from the nucleus to the cytoplasma. On the basis of the fact that the treatement by Triton X-100, disarranging the integrity of the NS membranous structure, preserves PC in relation to the fibrous layer as well as on the basis of the unequal nuclear pore state observed on the platinum-carbon replicas from nuclei splits it is supposed that PC can be formed in the nucleus and then in the course of repening ''built in'' PS

  20. Age and Chronicity of Administration Dramatically Influenced the Impact of Low Dose Paraquat Exposure on Behavior and Hypothalamic-Pituitary-Adrenal Activity

    Directory of Open Access Journals (Sweden)

    Chris A. Rudyk

    2017-07-01

    Full Text Available Little is known of the age-dependent and long-term consequences of low exposure levels of the herbicide and dopaminergic toxicant, paraquat. Thus, we assessed the dose-dependent effects of paraquat using a typical short-term (3 week exposure procedure, followed by an assessment of the effects of chronic (16 weeks exposure to a very low dose (1/10th of what previously induced dopaminergic neuronal damage. Short term paraquat treatment dose-dependently induced deficits in locomotion, sucrose preference and Y-maze performance. Chronic low dose paraquat treatment had a very different pattern of effects that were also dependent upon the age of the animal: in direct contrast to the short-term effects, chronic low dose paraquat increased sucrose consumption and reduced forced swim test (FST immobility. Yet these effects were age-dependent, only emerging in mice older than 13 months. Likewise, Y-maze spontaneous alternations and home cage activity were dramatically altered as a function of age and paraquat chronicity. In both the short and long-term exposure studies, increased corticosterone and altered hippocampal glucocorticoid receptor (GR levels were induced by paraquat, but surprisingly these effects were blunted in the older mice. Thus, paraquat clearly acts as a systemic stressor in terms of corticoid signaling and behavioral outcomes, but that paradoxical effects may occur with: (a repeated exposure at; (b very low doses; and (c older age. Collectively, these data raise the possibility that repeated “hits” with low doses of paraquat in combination with aging processes might have promoted compensatory outcomes.

  1. Genomic instability in mutation induction on normal human fibroblasts irradiated with chronic low-dose radiations in heavy-ion radiation field

    International Nuclear Information System (INIS)

    Suzuki, M.; Tsuruoka, C.; Uchihori, Y.; Yasuda, H.; Fujitaka, K.

    2003-01-01

    Full text: At a time when manned space exploration is more a reality with the planned the International Space Station (ISS) underway, the potential exposure of crews in a spacecraft to chronic low-dose radiations in the field of low-flux galactic cosmic rays (GCR) and the subsequent biological effects have become one of the major concerns of space science. We have studied both in vitro life span and genomic instability in cellular effects in normal human skin fibroblasts irradiated with chronic low-dose radiations in heavy-ion radiation field. Cells were cultured in a CO2 incubator, which was set in the irradiation room for the biological study of heavy ions in the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS), and irradiated with scattered radiations produced from heavy ions. Absorbed dose measured using a thermoluminescence dosimeter (TLD) and a Si-semiconductor detector was to be around 1.4 mGy per day when operating the HIMAC machine for biological experiments. The total population doubling number (tPDN) of low-dose irradiated cells was significantly smaller (79-93%) than that of unirradiated cells. The results indicate that the life span of the cell population shortens by irradiating with low-dose scattered radiations in the heavy-ion irradiation field. Genomic instability in cellular responses was examined to measure either cell killing or mutation induction in low-dose accumulated cells after exposing to X-ray challenging doses. The results showed that there was no enhanced effect on cell killing between low-dose accumulated and unirradiated cells after exposing to defined challenging doses of 200kV X rays. On the contrary, the mutation frequency on hprt locus of low-dose accumulated cells was much higher than that of unirradiated cells. The results suggested that genomic instability was induced in mutagenesis by the chronic low-dose irradiations in heavy-ion radiation field

  2. Neuropsychological effects of chronic low-dose exposure to polychlorinated biphenyls (PCBs: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Klett Martin

    2005-10-01

    Full Text Available Abstract Background Exposure to indoor air of private or public buildings contaminated with polychlorinated biphenyls (PCBs has raised health concerns in long-term users. This exploratory neuropsychological group study investigated the potential adverse effects of chronic low-dose exposure to specific air-borne low chlorinated PCBs on well-being and behavioral measures in adult humans. Methods Thirty employees exposed to indoor air contaminated with PCBs from elastic sealants in a school building were compared to 30 non-exposed controls matched for education and age, controlling for gender (age range 37–61 years. PCB exposure was verified by external exposure data and biological monitoring (PCB 28, 101, 138, 153, 180. Subjective complaints, learning and memory, executive function, and visual-spatial function was assessed by standardized neuropsychological testing. Since exposure status depended on the use of contaminated rooms, an objectively exposed subgroup (N = 16; PCB 28 = 0.20 μg/l; weighted exposure duration 17.9 ± 7 years was identified and compared with 16 paired controls. Results Blood analyses indicated a moderate exposure effect size (d relative to expected background exposure for total PCB (4.45 ± 2.44 μg/l; d = 0.4. A significant exposure effect was found for the low chlorinated PCBs 28 (0.28 ± 0.25 μg/l; d = 1.5 and 101 (0.07 ± 0.09 μg/l; d = 0.7. Although no neuropsychological effects exceeded the adjusted significance level, estimation statistics showed elevated effect sizes for several variables. The objectively exposed subgroup showed a trend towards increased subjective attentional and emotional complaints (tiredness and slowing of practical activities, emotional state as well as attenuated attentional performance (response shifting and alertness in a cued reaction task. Conclusion Chronic inhalation of low chlorinated PCBs that involved elevated blood levels was associated with a subtle attenuation of emotional well

  3. Chronic low-dose UVA irradiation induces local suppression of contact hypersensitivity, Langerhans cell depletion and suppressor cell activation in C3H/HeJ mice

    International Nuclear Information System (INIS)

    Bestak, Rosa; Halliday, G.M.

    1996-01-01

    It has previously been demonstrated that chronic low-dose solar-simulated UV radiation could induce both local and systemic immunosuppression as well as tolerance to a topically applied hapten. In this study, we have used a chronic low-dose UV-irradiation protocol to investigate the effects of UVA on the skin immune system of C3H/HeJ mice. Irradiation with UVA+B significantly suppressed the local and systemic primary contact hypersensitivity (CHS) response to the hapten 2,4,6-trinitrochlorobenzene. Furthermore, UVA+B reduced Langerhans cell (LC) and dendritic epidermal T cell (DETC) densities in chronically UV-irradiated mice. Ultraviolet A irradiation induced local, but not systemic, immunosuppression and reduced LC (32%) but not DETC from the epidermis compared to the shaved control animals. Treatment of mice with both UVA+B and UVA radiation also induced an impaired secondary CHS response, and this tolerance was transferable with spleen cells. (Author)

  4. Is low-dose amitriptyline effective in the management of chronic low back pain? Study protocol for a randomised controlled trial.

    Science.gov (United States)

    Urquhart, Donna M; Wluka, Anita E; Sim, Malcolm R; van Tulder, Maurits; Forbes, Andrew; Gibson, Stephen J; Arnold, Carolyn; Fong, Chris; Anthony, Shane N; Cicuttini, Flavia M

    2016-10-22

    Low back pain is a major clinical and public health problem, with limited evidence-based treatments. Low-dose antidepressants are commonly used to treat pain in chronic low back pain. However, their efficacy is unproven. The aim of this pragmatic, double-blind, randomised, placebo-controlled trial is to determine whether low-dose amitriptyline (an antidepressant) is more effective than placebo in reducing pain in individuals with chronic low back pain. One hundred and fifty individuals with chronic low back pain will be recruited through hospital and private medical and allied health clinics, advertising in local media and posting of flyers in community locations. They will be randomly allocated to receive either low-dose amitriptyline (25 mg) or an active placebo (benztropine mesylate, 1 mg) for 6 months. The primary outcome measure of pain intensity will be assessed at baseline, 3 and 6 months using validated questionnaires. Secondary measures of self-reported low back disability, work absence and hindrance in the performance of paid/unpaid work will also be examined. Intention-to-treat analyses will be performed. This pragmatic, double-blind, randomised, placebo-controlled trial will provide evidence regarding the effectiveness of low-dose antidepressants compared with placebo in reducing pain, disability, work absenteeism and hindrance in work performance in individuals with chronic low back pain. This trial has major public health and clinical importance as it has the potential to provide an effective approach to the management of chronic low back pain. Australian New Zealand Clinical Trials Registry: ACTRN12612000131853 ; registered on 30 January 2012.

  5. Interspecific transfer of only part of genome by fusion between non-irradiated protoplasts of Nicotiana glauca and X-ray irradiated protoplasts of N. Langsdorffii

    International Nuclear Information System (INIS)

    Itoh, K.; Futsuhara, Y.

    1983-01-01

    To transfer only part of genome, X-ray irradiated suspension cell protoplasts of N. langsdorffii were fused with suspension cell protoplasts of N. glauca by polyethylene glycol. Somatic hybrid calli were selected by the growth in the hormone-free medium. Some of somatic hybrid calli from fusion with irradiated protoplasts indicated the loss of small subunit polypeptide of fraction 1 protein which was coded by N. langsdorffii nuclear DNA. Cytological analysis provided an information on significant decrease of chromosomes in somatic hybrid calli from fusion with irradiated protoplasts, compared with the somatic hybrid calli from fusion with non-irradiated protoplasts. In addition, isozyme analysis revealed that somatic hybrid calli from fusion with irradiated protoplasts lost particular bands of N. langsdorffli. These results demonstrate the tranfer of only part of genome from N, langsdorffii to N, glauca by fusion with X-ray irradiated protoplasts

  6. A Threshold Exists in the Dose-response Relationship for Somatic Mutation Frequency Inducted by X-ray Irradiation of Drosophia

    International Nuclear Information System (INIS)

    Koana, T.; Takashima, Y.; Okada, M. O.; Ikehata, M.; Miyakoshi, J.; Sakai, K.

    2004-01-01

    The dose-response relationship of ionizing radiation and its stochastic effects has been thought to be linear without any thresholds. The basic data for this model was obtained from mutational assays in the male germ cells of fruits fly Drosophila melanogaster. However, carcinogenic activity should be examined more appropriately in somatic cells than in germ cells. Here, the dose-response relationship of X- ray irradiation and somatic mutation is examined in Drosophila. A threshold at approximately 1Gy was observed in the DNA repair proficient flies. In the repair deficient siblings, the threshold was smaller and the inclination of the dose-response curve was much steeper. These results suggest that the dose-response relationship between X-ray irradiation and somatic mutation has a threshold, and that the DNA repair function contributes to its formation. (Author) 35 refs

  7. Optically stimulated luminescence in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass

    Science.gov (United States)

    Nanto, H.; Nakagawa, R.; Takei, Y.; Hirasawa, K.; Miyamoto, Y.; Masai, H.; Kurobori, T.; Yanagida, T.; Fujimoto, Y.

    2015-06-01

    An intense optically stimulated luminescence (OSL) was observed, for the first time, in x-ray irradiated xSnO-(25-x)SrO-75B2O3 glass. It was found that the peak wavelength of OSL emission spectrum and its stimulation spectrum is about 400 nm and 600 nm, respectively. The OSL intensity is depended on the SnO contents (x=0.05-1.5) and the most intense OSL was observed in 1.0 mol% SnO doped glass. It was found that the OSL intensity is increased with increasing x-ray absorbed dose. Fairly good fading characteristics were observed in the x-ray irradiated glass, showing that this glass is useful as a candidate for OSL sensor materials for ionizing radiation monitoring.

  8. A track length estimator method for dose calculations in low-energy X-ray irradiations. Implementation, properties and performance

    Energy Technology Data Exchange (ETDEWEB)

    Baldacci, F.; Delaire, F.; Letang, J.M.; Sarrut, D.; Smekens, F.; Freud, N. [Lyon-1 Univ. - CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Centre Leon Berard (France); Mittone, A.; Coan, P. [LMU Munich (Germany). Dept. of Physics; LMU Munich (Germany). Faculty of Medicine; Bravin, A.; Ferrero, C. [European Synchrotron Radiation Facility, Grenoble (France); Gasilov, S. [LMU Munich (Germany). Dept. of Physics

    2015-05-01

    The track length estimator (TLE) method, an 'on-the-fly' fluence tally in Monte Carlo (MC) simulations, recently implemented in GATE 6.2, is known as a powerful tool to accelerate dose calculations in the domain of low-energy X-ray irradiations using the kerma approximation. Overall efficiency gains of the TLE with respect to analogous MC were reported in the literature for regions of interest in various applications (photon beam radiation therapy, X-ray imaging). The behaviour of the TLE method in terms of statistical properties, dose deposition patterns, and computational efficiency compared to analogous MC simulations was investigated. The statistical properties of the dose deposition were first assessed. Derivations of the variance reduction factor of TLE versus analogous MC were carried out, starting from the expression of the dose estimate variance in the TLE and analogous MC schemes. Two test cases were chosen to benchmark the TLE performance in comparison with analogous MC: (i) a small animal irradiation under stereotactic synchrotron radiation therapy conditions and (ii) the irradiation of a human pelvis during a cone beam computed tomography acquisition. Dose distribution patterns and efficiency gain maps were analysed. The efficiency gain exhibits strong variations within a given irradiation case, depending on the geometrical (voxel size, ballistics) and physical (material and beam properties) parameters on the voxel scale. Typical values lie between 10 and 103, with lower levels in dense regions (bone) outside the irradiated channels (scattered dose only), and higher levels in soft tissues directly exposed to the beams.

  9. Toward an organ based dose prescription method for the improved accuracy of murine dose in orthovoltage x-ray irradiators

    International Nuclear Information System (INIS)

    Belley, Matthew D.; Wang, Chu; Nguyen, Giao; Gunasingha, Rathnayaka; Chao, Nelson J.; Chen, Benny J.; Dewhirst, Mark W.; Yoshizumi, Terry T.

    2014-01-01

    Purpose: Accurate dosimetry is essential when irradiating mice to ensure that functional and molecular endpoints are well understood for the radiation dose delivered. Conventional methods of prescribing dose in mice involve the use of a single dose rate measurement and assume a uniform average dose throughout all organs of the entire mouse. Here, the authors report the individual average organ dose values for the irradiation of a 12, 23, and 33 g mouse on a 320 kVp x-ray irradiator and calculate the resulting error from using conventional dose prescription methods. Methods: Organ doses were simulated in the Geant4 application for tomographic emission toolkit using the MOBY mouse whole-body phantom. Dosimetry was performed for three beams utilizing filters A (1.65 mm Al), B (2.0 mm Al), and C (0.1 mm Cu + 2.5 mm Al), respectively. In addition, simulated x-ray spectra were validated with physical half-value layer measurements. Results: Average doses in soft-tissue organs were found to vary by as much as 23%–32% depending on the filter. Compared to filters A and B, filter C provided the hardest beam and had the lowest variation in soft-tissue average organ doses across all mouse sizes, with a difference of 23% for the median mouse size of 23 g. Conclusions: This work suggests a new dose prescription method in small animal dosimetry: it presents a departure from the conventional approach of assigninga single dose value for irradiation of mice to a more comprehensive approach of characterizing individual organ doses to minimize the error and uncertainty. In human radiation therapy, clinical treatment planning establishes the target dose as well as the dose distribution, however, this has generally not been done in small animal research. These results suggest that organ dose errors will be minimized by calibrating the dose rates for all filters, and using different dose rates for different organs

  10. Investigation of the internal electric field distribution under in situ x-ray irradiation and under low temperature conditions by the means of the Pockels effect

    International Nuclear Information System (INIS)

    Prekas, G; Sellin, P J; Veeramani, P; Davies, A W; Lohstroh, A; Oezsan, M E; Veale, M C

    2010-01-01

    The internal electric field distribution in cadmium zinc telluride (CdZnTe) x-ray and γ-ray detectors strongly affects their performance in terms of charge transport and charge collection properties. In CdZnTe detectors the electric field distribution is sensitively dependent on not only the nature of the metal contacts but also on the working conditions of the devices such as the temperature and the rate of external irradiation. Here we present direct measurements of the electric field profiles in CdZnTe detectors obtained using the Pockels electo-optic effect whilst under in situ x-ray irradiation. These data are also compared with alpha particle induced current pulses obtained by the transient current technique, and we discuss the influence of both low temperature and x-ray irradiation on the electric field evolution. Results from these studies reveal strong distortion of the electric field consistent with the build-up of space charge at temperatures below 250 K, even in the absence of external irradiation. Also, in the presence of x-ray irradiation levels a significant distortion in the electric field is observed even at room temperature which matches well the predicted theoretical model.

  11. Synchrotron X-ray irradiation effects on the device characteristics and the resistance to hot-carrier damage of MOSFETs with 4 nm thick gate oxides

    International Nuclear Information System (INIS)

    Tanaka, Yuusuke; Tanabe, Akira; Suzuki, Katsumi

    1998-01-01

    The effects of synchrotron x-ray irradiation on the device characteristics and hot-carrier resistance of n- and p-channel metal oxide semiconductor field effect transistors (MOSFETs) with 4 nm thick gate oxides are investigated. In p-channel MOSFETs, device characteristics were significantly affected by the x-ray irradiation but completely recovered after annealing, while the device characteristics in n-channel MOSFETs were not noticeably affected by the irradiation. This difference appears to be due to a difference in interface-state generation. In p-channel MOSFETs, defects caused by boron-ion penetration through the gate oxides may be sensitive to x-ray irradiation, causing the generation of many interface states. These interface states are completely eliminated after annealing in hydrogen gas. The effects of irradiation on the resistance to hot-carrier degradation in annealed 4 nm thick gate-oxide MOSFETs were negligible even at an x-ray dose of 6,000 mJ/cm 2

  12. Effect of localized intraoperative x-rays irradiation followed by intermittent external exposure on certain histochemical parameters related to pancreatic function

    International Nuclear Information System (INIS)

    Abdel-Azeem, M.G.

    2005-01-01

    The present study was carried out to evaluate the pancreatic enzyme activities in rabbits, whose splenic part of pancreas was exposed to local intraoperative radiation therapy (IORT) at level of 30 Gy X-rays followed by fractionated external radiation therapy (ERT) at a total dose of 40 Gy (2 Gy day after day) starting from the 15th day following the local intraoperative irradiation. The control pancreas was that received only external X-rays radiation without local irradiation. The exocrine pancreatic functions were assessed by determination of insulin hormone and enzyme activity of lipase as well as alkaline and acid phosphatases. After local X-rays irradiation on days 2 and 10 and after external X-rays irradiation on days 23 , 33 , 43 and 53, technovit-8100 plastic embedding (Kulzer and Heraeus) was used to prepare the cold blocks. The quantitative morphometric method was used to evaluate the histochemical pancreatic activity of the irradiated and control pancreas of each rabbit. Most of the studied parameters recorded non-significant changes as a result of the applied different levels of X-rays irradiation, which would give the chance to use this type of irradiation in pancreatic radiotherapy without any hazards to the pancreas

  13. Combined evaluation of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the identification of viable myocardium in patients with chronic coronary artery disease

    International Nuclear Information System (INIS)

    Pace, L.; Cuocolo, A.; Salvatore, M.; Perrone-Filardi, P.; Prastaro, M.; Vezzuto, P.; Crisci, T.; Dellegrottaglie, S.; Piscione, F.; Chiariello, M.; Mainenti, P.P.; Varrone, A.

    1998-01-01

    The purpose of this study was to evaluate whether combined evaluation by discriminant analysis of rest-redistribution thallium-201 tomography and low-dose dobutamine echocardiography enhances the accuracy in identifying viable myocardium in patients with chronic coronary artery disease. Rest-redistribution 201 Tl has high sensitivity but low specificity in identifying viable myocardium, while the opposite is true for low-dose dobutamine echocardiography. Forty-six patients underwent low-dose dobutamine echocardiography and rest-redistribution 201 Tl tomography on the same day. Rest echocardiography was repeated at least 30 days (mean 40±20) after myocardial revascularization. Discriminant analysis was applied to the results of 201 Tl tomography and dobutamine echocardiography to classify a/dyskinetic segments as viable or non-viable. In 92 a/dyskinetic segments that were revascularized, rest-redistribution 201 Tl tomography yielded an accuracy of 75%, while the accuracy of dobutamine echocardiography was 70% (P 201 Tl imaging are useful and complementary techniques for identifying viable myocardium in patients with chronic coronary artery disease. Combined evaluation by discriminant analysis significantly improves accuracy, although the cost-effectiveness of such an approach remains to be determined. (orig.)

  14. Expression and localization of Smad4 protein in mouse testis after whole-body X-ray irradiation

    International Nuclear Information System (INIS)

    Zhu Huaping; Zhang Yuanqiang; Zhao Jie; Zhao Yong; Ma Jing; Hou Wugang; Qi Yuhong

    2005-01-01

    The work is to determine whether and where Transforming growth factor-betas downstream Signaling molecule Smad4 is expressed in the testes after whole-body X-ray irradiation and shed light on the mechanisms of Transforming growth factor-betas/Smad signal pathway mediates cell fate decisions following X-ray exposure. Five groups of adult BALB/c mice, with ten mice in each group, received whole-body of X-ray at dose levels of 0.1 Gy, 0.5 Gy, 1.0 Gy, 1.5 Gy and 2.0 Gy. They were sacrificed at 16 hour, 1 week, 2 weeks, 3 weeks and 4 weeks after the irradiation. Cellular localization and expression changes were examined by immunohistochemical ABC method. Quantitative analysis of the immunostaining was made by an image analysis system. In the seminiferous tubules, the expression of Smad4 was modulated by irradiation. The immunostaining showed that 16 hour post-irradiation, there was a significant decline in the Leydig cell, and it was dose and time depended. In addition, the immunolocalization showed that Smad4 was not exclusively localized in the cytoplasm of Leydig cells, but also localized in various Stages of spermatogenesis after the exposure, especially in premeiotic spermatogonia and primary spermatocytes. There was just a little expression in the 2.0 Gy group 16 h after the irradiation and the 1.0 Gy and 1.5 Gy groups at 2 weeks after the irradiation. Therefore in the 0.1 Gy to 2.0 Gy groups at 3 weeks after the irradiation, the immunostaining positive cells were significantly increased in spermatogonia and primary spermatocytes. There was no significant change in sertoli cells with different doses and different times after the exposure. The different expression patterns and change by dose and time of Smad4, suggest that TGF-β/Smad signal pathway may affect aspect after X-ray impairment and Smad4 may play an important role during these periods. (authors)

  15. Chronic Low Dose Rate Ionizing Radiation Exposure Induces Premature Senescence in Human Fibroblasts that Correlates with Up Regulation of Proteins Involved in Protection against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Olga Loseva

    2014-07-01

    Full Text Available The risks of non-cancerous diseases associated with exposure to low doses of radiation are at present not validated by epidemiological data, and pose a great challenge to the scientific community of radiation protection research. Here, we show that premature senescence is induced in human fibroblasts when exposed to chronic low dose rate (LDR exposure (5 or 15 mGy/h of gamma rays from a 137Cs source. Using a proteomic approach we determined differentially expressed proteins in cells after chronic LDR radiation compared to control cells. We identified numerous proteins involved in protection against oxidative stress, suggesting that these pathways protect against premature senescence. In order to further study the role of oxidative stress for radiation induced premature senescence, we also used human fibroblasts, isolated from a patient with a congenital deficiency in glutathione synthetase (GS. We found that these GS deficient cells entered premature senescence after a significantly shorter time of chronic LDR exposure as compared to the GS proficient cells. In conclusion, we show that chronic LDR exposure induces premature senescence in human fibroblasts, and propose that a stress induced increase in reactive oxygen species (ROS is mechanistically involved.

  16. Effects of chronic exposure to low doses of ionizing radiation on the reproductive performance and outcome of an exposed population

    International Nuclear Information System (INIS)

    Mannino, J.A.

    1978-01-01

    This study was designed to test the hypothesis that low doses of ionizing radiation (cumulative dose less than 5.0 rads/yr) effects the reproductive history and/or outcome of a human population. Medically-related personnel who were exposed to low doses of radiation in the course of their employment were compared with medically-related personnel who were not routinely exposed to ionizing radiation. Each population consisted of 3000 persons from the states of Michigan and Ohio. Reproductive performance, history, and outcome of each sample population was compared statistically. Nineteen congenital defects and 47 postnatal defects were recorded for conceptions of the non-exposed population and 50 congenital defects and 83 postnatal defects were recorded for the exposed group. These groups were further broken down as to whether conception took place before, during, or after exposure and the results statistically analyzed. It was found that the exposure population had greater than expected numbers of postnatal defects and less than expected numbers of normal conceptions

  17. Updated estimates of survival and cost effectiveness for imatinib versus interferon-alpha plus low-dose cytarabine for newly diagnosed chronic-phase chronic myeloid leukaemia.

    Science.gov (United States)

    Reed, Shelby D; Anstrom, Kevin J; Li, Yanhong; Schulman, Kevin A

    2008-01-01

    For trials in which participants are followed beyond the main study period to assess long-term outcomes, economic evaluations conducted using short-term data should be systematically updated to reflect new information. We used 60-month survival data from the IRIS (International Randomized study of Interferon vs STI571) trial to update previously published cost-effectiveness estimates, based on 19 months of follow-up, of imatinib versus interferon (IFN)-alpha plus low-dose cytarabine in patients with chronic-phase chronic myeloid leukaemia. For patients treated with imatinib, we used the 60-month data to calibrate the survival curves generated from the original cost-effectiveness model. We used historical data to model survival for patients randomized to IFNalpha. We updated costs for medical resources using 2006 Medicare reimbursement rates and applied average wholesale prices (AWPs) and wholesale acquisition costs (WACs) to study medications. Five-year survival for patients randomized to imatinib was better than predicted in the original model (89.4% vs 83.2%). We estimated remaining life expectancy with first-line imatinib to be 19.1 life-years (3.8 life-years over the original model) and 15.2 QALYs (3.1 QALYs over the original estimate). Estimates for IFNalpha remained at 9.1 life-years and 6.3 QALYs. When we applied AWPs to study medications, incremental cost-effectiveness ratios (ICERs) were $US 51,800-57,500 per QALY. When we applied WACs, ICERs were $US 42,000-46,200 per QALY. Although the analysis revealed that the original survival estimates were conservative, the updated cost-effectiveness ratios were consistent with, or slightly higher than, the original estimates, depending on the method for assigning costs to study medications.

  18. Dose-rate effects and chronological changes of chromosome aberration rates in spleen cells from mice that are chronically exposed to gamma-ray at low dose rates

    International Nuclear Information System (INIS)

    Tanaka, Kimio; Kohda, Atsushi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Oghiso, Yoichi

    2006-01-01

    Dose-rate effects have not been examined in the low dose-rate regions of less than 60-600 mGy/h. Mice were chronically exposed to gamma-ray at 20 mGy/day (approximately 1 mGy/h) up to 700 days and at 1 mGy/day (approximately 0.05 mGy/h) for 500 days under SPF conditions. Chronological changes of chromosome aberration rates in spleen cells were observed along with accumulated doses at both low dose-rates. Unstable aberrations increased in a biphasic manner within 0-2 Gy and 4-14 Gy in 20 mGy/day irradiation. They slightly increased up to 0.5 Gy in 1 mGy/day irradiation. Chromosome aberration rates at 20 mGy/day and 1 mGy/day were compared at the same total doses of 0.5 Gy and 0.25 Gy. They were 2.0 vs. 0.53, and 1.0 vs. 0.47 respectively. Thus, dose-rate effects were observed in these low dose-rate regions. (author)

  19. Studies on possibility for alleviation of lifestyle diseases by low-dose irradiation or radon inhalation

    International Nuclear Information System (INIS)

    Kataoka, T.; Sakoda, A.; Yoshimoto, M.; Nakagawa, S.; Toyota, T.; Nishiyama, Y.; Yamato, K.; Ishimori, Y.; Kawabe, A.; Hanamoto, K.; Taguchi, T.; Yamaoka, K.

    2011-01-01

    Our previous studies showed the possibility that activation of the anti-oxidative function alleviates various oxidative damages, which are related to lifestyle diseases. Results showed that, low-dose X-ray irradiation activated superoxide dismutase and inhibits oedema following ischaemia-reperfusion. To alleviate ischaemia-reperfusion injury with transplantation, the changes of the anti-oxidative function in liver graft using low-dose X-ray irradiation immediately after exenteration were examined. Results showed that liver grafts activate the anti-oxidative function as a result of irradiation. In addition, radon inhalation enhances the anti-oxidative function in some organs, and alleviates alcohol-induced oxidative damage of mouse liver. Moreover, in order to determine the most effective condition of radon inhalation, mice inhaled radon before or after carbon tetrachloride (CCl 4 ) administration. Results showed that radon inhalation alleviates CCl 4 -induced hepatopathy, especially prior inhalation. It is highly possible that adequate activation of anti-oxidative functions induced by low-dose irradiation can contribute to preventing or reducing oxidative damages, which are related to lifestyle diseases. (authors)

  20. Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

    Science.gov (United States)

    Sadjadpour, Susan; Safarian, Shahrokh; Zargar, Seyed Jalal; Sheibani, Nader

    2016-01-01

    In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  1. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V.; Ershova, Liza S. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Osipov, Andrian N. [Federal Medial and Biological Center named after Burnazyan of the Federal Medical and Biological Agency (FMBTz named after Burnazyan of FMBA), Moscow (Russian Federation); State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya, 46, Moscow, 123098 (Russian Federation); Zhuravleva, Veronika F.; Pankratova, Galina V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N.; Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation)

    2015-09-15

    Highlights: • The chronic exposure to low-dose IR induces DSBs in human lymphocytes (TM index). • Exposure to IR decreases the level of human circulating DNA (cfDNA index). • IR induces an increase of DNase1 activity (DNase1 index) in plasma. • IR induces an increase of the level of antibodies to DNA (Ab DNA index) in plasma. • The ratio cfDNA/(DNase 1 × Ab DNA × TM) is a potential marker of human exposure to IR. - Abstract: The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism’s cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1 × Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab

  2. Sperm mRNA transcripts are indicators of sub-chronic low dose testicular injury in the Fischer 344 rat.

    Directory of Open Access Journals (Sweden)

    Sara E Pacheco

    Full Text Available Current human reproductive risk assessment methods rely on semen and serum hormone analyses, which are not easily comparable to the histopathological endpoints and mating studies used in animal testing. Because of these limitations, there is a need to develop universal evaluations that reliably reflect male reproductive function. We hypothesized that toxicant-induced testicular injury can be detected in sperm using mRNA transcripts as indicators of insult. To test this, we exposed adult male Fischer 344 rats to low doses of model testicular toxicants and classically characterized the testicular injury while simultaneously evaluating sperm mRNA transcripts from the same animals. Overall, this study aimed to: 1 identify sperm transcripts altered after exposure to the model testicular toxicant, 2,5-hexanedione (HD using microarrays; 2 expand on the HD-induced transcript changes in a comprehensive time course experiment using qRT-PCR arrays; and 3 test these injury indicators after exposure to another model testicular toxicant, carbendazim (CBZ. Microarray analysis of HD-treated adult Fischer 344 rats identified 128 altered sperm mRNA transcripts when compared to control using linear models of microarray analysis (q<0.05. All transcript alterations disappeared after 3 months of post-exposure recovery. In the time course experiment, time-dependent alterations were observed for 12 candidate transcripts selected from the microarray data based upon fold change and biological relevance, and 8 of these transcripts remained significantly altered after the 3-month recovery period (p<0.05. In the last experiment, 8 candidate transcripts changed after exposure to CBZ (p<0.05. The two testicular toxicants produced distinct molecular signatures with only 4 overlapping transcripts between them, each occurring in opposite directions. Overall, these results suggest that sperm mRNA transcripts are indicators of low dose toxicant-induced testicular injury in the rat.

  3. Growing central axons deprived of normal target neurones by neonatal X-ray irradiation still terminate in a precisely laminated fashion

    International Nuclear Information System (INIS)

    Laurberg, S.; Hjorth-Simonsen, A.

    1977-01-01

    Some studies are described on rat pups. The object was to study the fate of axons that normally terminate in a highly selective laminar fashion in the molecular layer of the medial limb of the dentate gyrus of the mammalian cerebral cortex when this is removed by neonatal X-ray irradiation. The rats were shielded with Pb, except for a field above the hippocampus and the dentate gyrus, and exposed to X-rays from a 250 kV source at a distance of 34 cm. (U.K.)

  4. DNA methylation and potential multigenerational epigenetic effects linked to uranium chronic low-dose exposure in gonads of males and females rats.

    Science.gov (United States)

    Elmhiri, G; Gloaguen, C; Grison, S; Kereselidze, D; Elie, C; Tack, K; Benderitter, M; Lestaevel, P; Legendre, A; Souidi, M

    2018-01-05

    An increased health problem in industrialised countries is the contemporary concern of public and scientific community as well. This has been attributed in part to accumulated environmental pollutants especially radioactive substances and the use of nuclear power plants worldwide. However, the outcome of chronic exposure to low doses of a radionuclide such as uranium remains unknown. Recently, a paradigm shift in the perception of risk of radiotoxicology has emerged through investigating the possibility of transmission of biological effects over generations, in particular by epigenetic pathways. These processes are known for their crucial roles associated with the development of several diseases. The current work investigates the epigenetic effect of chronic exposure to low doses of uranium and its inheritance across generations. Materials and Methods To test this proposition, a rodent multigenerational model, males and females, were exposed to a non-toxic concentration of uranium (40mgL -1 drinking water) for nine months. The uranium effects on were evaluated over three generations (F0, F1 and F2) by analysing the DNA methylation profile and DNMT genes expression in ovaries and testes tissues. Here we report a significant hypermethylation of testes DNA (p <0.005) whereas ovaries showed hypomethylated DNA (p <0.005). Interestingly, this DNA methylation profile was significantly maintained across generations F0, F1 and F2. Furthermore, qPCR results of both tissues imply a significant change in the expression of DNA methyltransferase genes (DNMT 1 and DNMT3a/b) as well. Altogether, our work demonstrates for the first time a sex-dependance and inheritance of epigenetic marks, DNA methylation, as a biological response to the exposure to low doses of uranium. However, it is not clear which type of reproductive cell type is more responsive in this context. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Thermoluminescent dosimeters for low dose X-ray measurements

    International Nuclear Information System (INIS)

    Del Sol Fernández, S.; García-Salcedo, R.; Sánchez-Guzmán, D.; Ramírez-Rodríguez, G.; Gaona, E.; León-Alfaro, M.A. de; Rivera-Montalvo, T.

    2016-01-01

    The response of TLD-100, CaSO_4:Dy and LiF:Mg,Cu,P for a range of X-ray low dose was measured. For calibration, the TLDs were arranged at the center of the X-ray field. The dose output of the X-ray machine was determined using an ACCU-Gold. All dosimeters were exposed at the available air kerma values of 14.69 mGy within a field 10×10 cm"2 at 80 cm of SSD. Results of LiF:Mg,Cu,P X-ray irradiated showed 4.8 times higher sensitivity than TLD-100. Meanwhile, TL response of CaSO_4:Dy exposed at the same dose was 5.6 time higher than TLD-100. Experimental results show for low dose X-ray measurements a better linearity for LiF:Mg,Cu,P compared with that of TLD-100. CaSO_4:Dy showed a linearity from 0.1 to 60 mGy - Highlights: • Low dose X-ray doses for personal dosimetry were measured. • Radiation dose (µGy ) for environmental dosimetry were determined. • Scattering radiation dose were measured by TLDs. • Linearity of pair TLD system was successful in the range of microgray. • Pair TLDs composed by CaSO_4:Dy and by LiF:Mg,Cu,P. is suggested for clinical dosimetry.

  6. Effects of chronic exposure of seeds and seeds and seedlings of Arabidopsis Thaliana by low doses of γ-radiation on plant growth and development

    International Nuclear Information System (INIS)

    Litvinov, S.V.

    2013-01-01

    Article presents the results of research on the effect of chronic γ-irradiation in small doses on A. Thaliana seedlings and seeds growth and development. Exposure rate for the seeds was 0,45 mGy/h (total absorbed dose 30 cSv) and 0,18 mGy/h for seedlings (total absorbed dose 3 cSv). Statistically significant differences in the germination capacity, in the time of primary leaf rosette formation, in the hypocotyl length were revealed between irradiated and control seedlings. Plants from irradiated seeds differed by the higher growth rate of stem, they flowered and fruited earlier, but they also characterized on average shorter vegetative cycle in comparison with control plants. In our experiments it is shown significant impact of chronic low doses of γ-irradiation of seeds and seedlings on the ontogeny in A. Thaliana and on the parameters that reflect the growth and development of the irradiated plants

  7. Soft x-ray irradiation effects of Li₂O₂, Li₂CO₃ and Li₂O revealed by absorption spectroscopy.

    Directory of Open Access Journals (Sweden)

    Ruimin Qiao

    Full Text Available Li(2O(2, Li(2CO(3, and Li(2O are three critical compounds in lithium-air and lithium-ion energy storage systems. Extensive measurements have been carried out to study the chemical species and their evolutions at difference stages of the device operation. While x-ray spectroscopy has been demonstrated to be one of the most powerful tools for such purpose, no systematic study on the irradiation effects have been reported. Here we carry out extensive time, position, and irradiation dependent Li K-edge soft x-ray absorption spectroscopy on these compounds with so far the best energy resolution. The ultra-high resolution in the current study allows the features in the absorption spectra to be well-resolved. The spectral lineshape thus serves as the fingerprints of these compounds, enabling the tracking of their evolution under x-ray irradiation. We found that both Li(2O(2 and Li(2CO(3 evidently evolve towards Li(2O under the soft x-ray irradiation with Li(2CO(3 exhibiting a surprisingly higher sensitivity to x-rays than Li(2O(2. On the other hand, Li(2O remains the most stable compound despite experiencing substantial irradiation dose. We thus conclude that high resolution soft x-ray spectroscopy could unambiguously fingerprint different chemical species, but special cautions on irradiation effects would be needed in performing the experiments and interpreting the data properly.

  8. Experimental analysis of embryogenesis of cerebellum in rat. II. Morphogenetic malformations following x-ray irradiation on day 18 of gestation

    International Nuclear Information System (INIS)

    Das, G.D.

    1977-01-01

    Rat embryos of 18 days gestation were exposed in utero to 170 R of x-ray irradiation. Embryos were collected six hours, 1, 2, and 3 days after irradiation, and animals of 2-, 6-, 15- and 30-day-old postnatal age were sacrificed. Six hours after irradiation pyknosis of cells was noticed in the external granular layer along the posterior aspect of the cerebellum. Neuroblasts, destined to differentiate into Purkinje cells, were found arrested in their migratory path. During subsequent periods of embryogenesis the external granular layer was found recovered, and clustering of the neuroblasts were disorganized and fragmented. This abnormal clustering of neuroblasts was permanent, and the external granular layer followed the same abnormal pattern in its growth. During postnatal development the internal granular layer also was found to follow the abnormal pattern of Purkinje cell layer. Those abnormal developmental events were seen to lead to malformed folia in the anterior regions of the cerebellum. In addition to it the cerebellum of x-ray irradiated animals appeared smaller than the normal. Issues having a bearing on the differential radiosensitivity of different cells, factors determining the small size of the cerebellum, and cellular events determining the morphogenetic malformations are discussed

  9. Dietary supplementation with low-dose omega-3 fatty acids reduces salivary tumor necrosis factor-α levels in patients with chronic periodontitis: a randomized controlled clinical study.

    Science.gov (United States)

    Keskiner, I; Saygun, I; Bal, V; Serdar, M; Kantarci, A

    2017-08-01

    Recent studies have demonstrated the beneficial effects of omega-3 polyunsaturated fatty acids (PUFAs) on physiological processes and on a variety of chronic inflammatory diseases, including periodontal diseases. In this study, we evaluated the impact of omega-3 PUFAs in conjunction with scaling and root planing (SRP) on salivary markers in patients with chronic periodontitis. Thirty systemically healthy subjects with chronic periodontitis were enrolled and randomly allocated into two groups. The control group (n = 15) was treated with SRP + placebo whereas the test group was treated with SRP and dietary supplementation of low-dose omega-3 PUFAs (6.25 mg eicosapentaenoic acid and 19.19 mg docosahexaenoic acid). Clinical parameters were taken at baseline, 1, 3 and 6 mo following therapy. Saliva samples were obtained at the same time intervals and analyzed for tumor necrosis factor-α (TNF-α) and superoxide dismutase (SOD). Both groups showed significant changes in clinical parameters in response to treatment compared to baseline with no significant difference between groups. Salivary TNF-α levels showed a statistically significant decrease in the test group at 6 mo compared to the control group. Salivary SOD levels increased significantly at 3 and 6 mo in the test group and at 6 mo in placebo groups compared to baseline with no statistically significant differences between the groups. The results demonstrated that dietary supplementation with low-dose omega-3 PUFAs improves salivary TNF-α without any significant impact on clinical parameters in patients with chronic periodontitis, suggesting that the systemic benefits of dietary omega-3 PUFAs may not be translated to periodontal health. (ClinicalTrials.gov ID NCT02719587). © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.R. Vivek, E-mail: prvkumar06@gmail.com [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Seshadri, M. [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jaikrishan, G. [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Das, Birajalaxmi [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-05-15

    Highlights: • Effect of chronic low dose natural radiation in radio adaptive response studied. • PBMCs of subjects from NLNRA and HLNRA were challenged with gamma radiation. • DNA damage and repair in PBMCs was compared using the alkaline comet assay. • Significant reduction in DNA damage in subjects of high dose group from HLNRA noted. • Probable induction of an in vivo radio adaptive response in subjects from HLNRA. - Abstract: This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year{sup −1}), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N = 43, range 1.07 mSv year{sup −1} to 5.55 mSv year{sup −1}) and 9.62 mSv (N = 34, range 6.07 mSv year{sup −1} to17.41 mSv year{sup −1}), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P = 0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from

  11. Low-Dose Tramadol and Non-Steroidal Anti-Inflammatory Drug Combination Therapy Prevents the Transition to Chronic Low Back Pain.

    Science.gov (United States)

    Inage, Kazuhide; Orita, Sumihisa; Yamauchi, Kazuyo; Suzuki, Takane; Suzuki, Miyako; Sakuma, Yoshihiro; Kubota, Go; Oikawa, Yasuhiro; Sainoh, Takeshi; Sato, Jun; Fujimoto, Kazuki; Shiga, Yasuhiro; Abe, Koki; Kanamoto, Hirohito; Inoue, Masahiro; Kinoshita, Hideyuki; Takahashi, Kazuhisa; Ohtori, Seiji

    2016-08-01

    Retrospective study. To determine whether low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy could prevent the transition of acute low back pain to chronic low back pain. Inadequately treated early low back pain transitions to chronic low back pain occur in approximately 30% of affected individuals. The administration of non-steroidal anti-inflammatory drugs is effective for treatment of low back pain in the early stages. However, the treatment of low back pain that is resistant to non-steroidal anti-inflammatory drugs is challenging. Patients who presented with acute low back pain at our hospital were considered for inclusion in this study. After the diagnosis of acute low back pain, non-steroidal anti-inflammatory drug administration was started. Forty patients with a visual analog scale score of >5 for low back pain 1 month after treatment were finally enrolled. The first 20 patients were included in a non-steroidal anti-inflammatory drug group, and they continued non-steroidal anti-inflammatory drug therapy for 1 month. The next 20 patients were included in a combination group, and they received low-dose tramadol plus non-steroidal anti-inflammatory drug combination therapy for 1 month. The incidence of adverse events and the improvement in the visual analog scale score at 2 months after the start of treatment were analyzed. No adverse events were observed in the non-steroidal anti-inflammatory drug group. In the combination group, administration was discontinued in 2 patients (10%) due to adverse events immediately following the start of tramadol administration. At 2 months, the improvement in the visual analog scale score was greater in the combination group than in the non-steroidal anti-inflammatory drug group (ppain to chronic low back pain.

  12. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Liza S; Osipov, Andrian N; Zhuravleva, Veronika F; Pankratova, Galina V; Porokhovnik, Lev N; Veiko, Natalia N

    2015-09-01

    The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism's cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1×Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab DNA and TM values may provide the information about the human organism's cell resistivity to chronic exposure to the low-dose IR and about the development of the adaptive response in the organism that is aimed, firstly, at the effective cfDNA elimination from the blood circulation, and, secondly - at survival of the cells, including the cells with the damaged DNA. Copyright © 2015. Published by Elsevier B.V.

  13. Assessment of pulmonary function using pixel indexes of multiple-slice spiral CT low-dose two-phase scanning in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Zhang Lihua; Wang Yunhua; Jiang Zhongbiao; Zhang Lejun; Sun Wanli; Zhang Chunming

    2012-01-01

    Objective: To explore the values of pixel indexes (PI) with multiple-slice spiral CT low-dose two-phase scanning for assessing the pulmonary function in chronic obstructive pulmonary disease (COPD). Methods: Thirty-six patients with COPD (COPD group)and 30 healthy people (control group)underwent pulmonary function test (PFT). Chest 64-MSCT low-dose (50 mAs) scanning at full inspiration and expiration, routine scanning (100 mAs) at inspiration were performed. The effective dose (ED) was calculated. The lung was divided into three regions (upper, middle, lower). PI of lung were divided into five groups: -960--1024, -910--960, -800--910, -700--800, -400--700. The PI -910 (sum of the PI under -910 HU) of low-dose scanning at each region were measured and calculated using pulmo software. All PI included PIin -910 , PIiex -910 , PIin -910 -PIiex -910 , PIiex -910 /PIin -910 and (PIin -910 -PIiex -910 )/PIin -910 . All patients underwent PFT within 3 days after 64-MSCT canning, FEV1% and FEV1/FVC were selected for comparison. Results: The PIin in three regions (-960 - -1024, -910 - -960, -800 - -910) were statistically significant between normal and COPD groups (U=0.00, 57.00, 20.50, P<0.01). The PIex in all regions were statistically significant (U=0.00, 0.00, 71.52, 191.00, 6.00, P<0.01). PI -910--1024 at expiration and inspiration were correlated with FEV1% and FEV1/FVC (r=-0.548, -0.664, -0.752, -0.781, P<0.01). PIin -910 , PIex -910 ,PIiex -910 /PIin -910 , (PIin -910 -PIex -910 )/PIin -910 had a good correlation with FEV1% and FEV1/FVC (r=-0.548, -0.664, -0.752, -0.781, -0.674, -0.642, 0.674, 0.642, P<0.01). Conclusion: Pixel indexes of 64-MSCT low-dose two-phase scanning can be used to evaluate pulmonary function in COPD patients. (authors)

  14. Use of low-dose oral theophylline as an adjunct to inhaled corticosteroids in preventing exacerbations of chronic obstructive pulmonary disease: study protocol for a randomised controlled trial.

    Science.gov (United States)

    Devereux, Graham; Cotton, Seonaidh; Barnes, Peter; Briggs, Andrew; Burns, Graham; Chaudhuri, Rekha; Chrystyn, Henry; Davies, Lisa; De Soyza, Anthony; Fielding, Shona; Gompertz, Simon; Haughney, John; Lee, Amanda J; McCormack, Kirsty; McPherson, Gladys; Morice, Alyn; Norrie, John; Sullivan, Anita; Wilson, Andrew; Price, David

    2015-06-10

    Chronic obstructive pulmonary disease (COPD) is associated with high morbidity, mortality, and health-care costs. An incomplete response to the anti-inflammatory effects of inhaled corticosteroids is present in COPD. Preclinical work indicates that 'low dose' theophylline improves steroid responsiveness. The Theophylline With Inhaled Corticosteroids (TWICS) trial investigates whether the addition of 'low dose' theophylline to inhaled corticosteroids has clinical and cost-effective benefits in COPD. TWICS is a randomised double-blind placebo-controlled trial conducted in primary and secondary care sites in the UK. The inclusion criteria are the following: an established predominant respiratory diagnosis of COPD (post-bronchodilator forced expiratory volume in first second/forced vital capacity [FEV1/FVC] of less than 0.7), age of at least 40 years, smoking history of at least 10 pack-years, current inhaled corticosteroid use, and history of at least two exacerbations requiring treatment with antibiotics or oral corticosteroids in the previous year. A computerised randomisation system will stratify 1424 participants by region and recruitment setting (primary and secondary) and then randomly assign with equal probability to intervention or control arms. Participants will receive either 'low dose' theophylline (Uniphyllin MR 200 mg tablets) or placebo for 52 weeks. Dosing is based on pharmacokinetic modelling to achieve a steady-state serum theophylline of 1-5 mg/l. A dose of theophylline MR 200 mg once daily (or placebo once daily) will be taken by participants who do not smoke or participants who smoke but have an ideal body weight (IBW) of not more than 60 kg. A dose of theophylline MR 200 mg twice daily (or placebo twice daily) will be taken by participants who smoke and have an IBW of more than 60 kg. Participants will be reviewed at recruitment and after 6 and 12 months. The primary outcome is the total number of participant-reported COPD exacerbations requiring

  15. [Study of genome instability using DNA fingerprinting of the offspring of male mice subjected to chronic low dose gamma irradiation].

    Science.gov (United States)

    Bezlepkin, V G; Vasil'eva, G V; Lomaeva, M G; Sirota, N P; Gaziev, A I

    2000-01-01

    By a polymerase chain reaction with an arbitrary primer (AP-PCR), the possibility of transmission of genome instability to somatic cells of the offspring (F1 generation) from male parents of mice exposed to chronic low-level gamma-radiation was studied. Male BALB/c mice 15 days after exposure to 10-50 cGy were mated with unirradiated females. Biopsies were taken from tale tips of two month-old offspring mice and DNA was isolated. The primer in the AP-PCR was a 20-mer oligonucleotide flanking the microsatellite locus Atp1b2 on chromosome 11 of the mouse. A comparative analysis of individual fingerprints of AP-PCR products on DNA-templates from the offspring of irradiated and unirradiated male mice revealed an increased variability of microsatellite-associated sequences in the genome of the offspring of the males exposed to 25 and 50 cGy. The DNA-fingerprints of the offspring of male mice exposed to chronic irradiation with the doses 10 and 25 cGy 15 days before fertilization (at the post-meiotic stage of spermatogenesis) showed an increased frequency of "non-parent bands". The results of the study point to the possibility of transmission to the offspring somatic cells of changes increasing genome instability from male parents exposed to chronic low-level radiation prior to fertilization.

  16. Clastogenic effects in human lymphocytes exposed to low and high dose rate X-ray irradiation and vitamin C

    International Nuclear Information System (INIS)

    Konopacka, M; Rogolinski, J.

    2011-01-01

    In the present work we investigated the ability of vitamin C to modulate clastogenic effects induced in cultured human lymphocytes by X-irradiation delivered at either high (1 Gy/min) or low dose rate (0.24 Gy/min). Biological effects of the irradiation were estimated by cytokinesis-block micronucleus assay including the analysis of the frequency of micronuclei (MN) and apoptotic cells as well as calculation of nuclear division index (NDI). The numbers of micronucleated binucleate lymphocytes (MN-CBL) were 24.85 ± 2.67% and 32.56 ± 3.17% in cultures exposed to X-rays (2 Gy) delivered at low and high dose rates, respectively. Addition of vitamin C (1-20 μg/ml) to the medium of cultures irradiated with the low dose rate reduced the frequency of micronucleated lymphocytes with multiple MN in a concentration-dependent manner. Lymphocytes exposed to the high dose rate radiation showed a U-shape response: low concentration of vitamin C significantly reduced the number of MN, whereas high concentration influenced the radiation-induced total number of micronucleated cells insignificantly, although it increased the number of cells with multiple MN. Addition of vitamin C significantly reduced the fraction of apoptotic cells, irrespective of the X-ray dose rate. These results indicate that radiation dose rate is an important exposure factor, not only in terms of biological cell response to irradiation, but also with respect to the modulating effects of antioxidants. (authors)

  17. Maintenance of remission with low-dose olopatadine hydrochloride for itch in well-controlled chronic urticaria

    Directory of Open Access Journals (Sweden)

    Makino T

    2012-09-01

    Full Text Available Teruhiko Makino,1 Yoshiaki Takegami,1 Mati Ur Rehman,1 Yoko Yoshihisa,1 Waka Ishida,2 Takashi Toyomoto,3 Tadamichi Shimizu11Department of Dermatology, University of Toyama, Toyama, Japan; 2Department of Dermatology, Niigata Central Hospital, Joetsu, Japan; 3Department of Dermatology, Saiseikai Takaoka Hospital, Takaoka, JapanBackground: The long-term follow-up of chronic urticaria (CU is important to ensure the adequate treatment of patients. Olopatadine hydrochloride is one of the second-generation nonsedating antihistamines.Methods: This study was designed to assess the optimal dose of olopatadine to suppress symptoms of chronic urticarial itch in well-controlled patients. After CU patients were treated with 10 mg olopatadine, patients having a visual analogue scale (VAS itch score of less than 20 were randomly allocated into one of three groups: 10 mg/day (n = 35, 5 mg/day (n = 30, or no medication (n = 32.Results: The suppressive effects of both the 5 mg and 10 mg olopatadine treatments on the VAS itch score were more significant and longer lasting over a period of 4 weeks than the no-medication treatment. Both the 5-mg group and the 10-mg group showed improved urticarial symptoms and maintained their VAS itch score within normal limits compared to the no-medication group. The differences between the 5-mg and 10-mg groups were not significant.Conclusion: These results demonstrate that treatment with olopatadine at a dose of 5 mg once daily is effective and safe for the management and prevention of CU symptoms for itch in well-controlled patients.Keywords: chronic urticaria, olopatadine, dose, antihistamine, itch, histamine

  18. Phase II study of palliative low-dose local radiotherapy in disseminated indolent non-Hodgkin's lymphoma and chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Jóhannsson, Jakob; Specht, Lena; Mejer, Johannes

    2002-01-01

    of the palliative effect of this regimen in patients with disseminated INHL or CLL. METHODS AND MATERIALS: Twenty-two patients (11 men, 11 women, median age 62 years, range 30-89) with disseminated INHL (n = 15) or CLL (n = 7) were treated with local low-dose RT, 2 Gy x 2 within 3 days, with the aim of achieving......PURPOSE: Indolent non-Hodgkin's lymphoma (INHL) and chronic lymphocytic leukemia (CLL) are highly sensitive to radiotherapy (RT). Previous retrospective studies have shown high response rates after local palliative RT of 4 Gy in 2 fractions, which prompted this prospective Phase II trial...... palliation from localized lymphoma masses. The patients were treated to a total of 31 different sites. Seventeen patients had previously been treated with chemotherapy. The median observation time after the start of RT was 8 months (range 3-26). RESULTS: All patients and all irradiated sites were assessable...

  19. Low doses effects

    International Nuclear Information System (INIS)

    Tubiana, M.

    1997-01-01

    In this article is asked the question about a possible carcinogens effect of low dose irradiation. With epidemiological data, knowledge about the carcinogenesis, the professor Tubiana explains that in spite of experiments made on thousand or hundred of thousands animals it has not been possible to bring to the fore a carcinogens effect for low doses and then it is not reasonable to believe and let the population believe that low dose irradiation could lead to an increase of neoplasms and from this point of view any hardening of radiation protection standards could in fact, increase anguish about ionizing radiations. (N.C.)

  20. Chronic exposure of adult, postnatal and in utero rat models to low-dose 137Cesium: impact on circulating biomarkers

    International Nuclear Information System (INIS)

    Manens, Line; Grison, Stéphane; Bertho, Jean-Marc; Lestaevel, Philippe; Guéguen, Yann; Benderitter, Marc; Aigueperse, Jocelyne; Souidi, Maâmar

    2016-01-01

    The presence of 137 Cesium ( 137 Cs) in the environment after nuclear accidents at Chernobyl and more recently Fukushima Daiichi raises many health issues for the surrounding populations chronically exposed through the food chain. To mimic different exposure situations, we set up a male rat model of exposure by chronic ingestion of a 137 Cs concentration likely to be ingested daily by residents of contaminated areas (6500 Bq.l −1 ) and tested contaminations lasting 9 months for adult, neonatal and fetal rats. We tested plasma and serum biochemistry to identify disturbances in general indicators (lipids, proteins, carbohydrates and electrolytes) and in biomarkers of thyroid, heart, brain, bone, kidney, liver and testis functions. Analysis of the general indicators showed increased levels of cholesterol (+26%), HDL cholesterol (+31%), phospholipids B (+15%) and phosphorus (+100%) in the postnatal group only. Thyroid, heart, brain, bone and kidney functions showed no blood changes in any model. The liver function evaluation showed changes in total bilirubin (+67%) and alkaline phosphatase (–11%) levels, but only for the rats exposed to 137 Cs intake in adulthood. Large changes in 17β-estradiol (–69%) and corticosterone (+36%) levels affected steroidogenesis, but only in the adult model. This study showed that response profiles differed according to age at exposure: lipid metabolism was most radiosensitive in the postnatal model, and steroid hormone metabolism was most radiosensitive in rats exposed in adulthood. There was no evidence of deleterious effects suggesting a potential impact on fertility or procreation.

  1. Metabolomics reveals dose effects of low-dose chronic exposure to uranium in rats: identification of candidate biomarkers in urine samples.

    Science.gov (United States)

    Grison, Stéphane; Favé, Gaëlle; Maillot, Matthieu; Manens, Line; Delissen, Olivia; Blanchardon, Éric; Dublineau, Isabelle; Aigueperse, Jocelyne; Bohand, Sandra; Martin, Jean-Charles; Souidi, Maâmar

    2016-01-01

    Data are sparse about the potential health risks of chronic low-dose contamination of humans by uranium (natural or anthropogenic) in drinking water. Previous studies report some molecular imbalances but no clinical signs due to uranium intake. In a proof-of-principle study, we reported that metabolomics is an appropriate method for addressing this chronic low-dose exposure in a rat model (uranium dose: 40 mg L -1 ; duration: 9 months, n = 10). In the present study, our aim was to investigate the dose-effect pattern and identify additional potential biomarkers in urine samples. Compared to our previous protocol, we doubled the number of rats per group (n = 20), added additional sampling time points (3 and 6 months) and included several lower doses of natural uranium (doses used: 40, 1.5, 0.15 and 0.015 mg L -1 ). LC-MS metabolomics was performed on urine samples and statistical analyses were made with SIMCA-P+ and R packages. The data confirmed our previous results and showed that discrimination was both dose and time related. Uranium exposure was revealed in rats contaminated for 9 months at a dose as low as 0.15 mg L -1 . Eleven features, including the confidently identified N1-methylnicotinamide, N1-methyl-2-pyridone-5-carboxamide and 4-hydroxyphenylacetylglycine, discriminated control from contaminated rats with a specificity and a sensitivity ranging from 83 to 96 %, when combined into a composite score. These findings show promise for the elucidation of underlying radiotoxicologic mechanisms and the design of a diagnostic test to assess exposure in urine, in a dose range experimentally estimated to be above a threshold between 0.015 and 0.15 mg L -1 .

  2. Effects of x-ray irradiation on the induction of. cap alpha. -amylase synthesis by gibberelic acid in the aleurone system of barley

    Energy Technology Data Exchange (ETDEWEB)

    Zellner, H

    1974-01-01

    The influence of ionizing radiation on a system without DNA replication and cell division was investigated with the aid of GA/sub 3/-induced ..cap alpha..-amylase synthesis in aleurone cells of barley. The reaction of the system was determined by dose effect curves (after irradiation of one half of the endosperms in rest) for the synthesis and secretion of ..cap alpha..-amylase, protein, and reducing sugars. The system proves to be highly radiation-resistant. The course of the synthesis of ..cap alpha..-amylase after X-ray irradiation with varying doses during enzyme synthesis suggests that transcription occurs in the middle of the lag-phase and is the most sensitive stage in enzyme synthesis, while translation alone is less sensitive to radiation.

  3. In vivo and in situ investigative results of repair and recovery processes during ontogenesis, after X-ray irradiation of bean seeds

    International Nuclear Information System (INIS)

    Koeroesi, F.; Jezierska-Szabo, E.; Szoeke, P.

    1999-01-01

    When exposing plant organs to high doses of ionizing radiation, disorders in growth and development or even lethality may occur. With the aim of modelling this phenomenon, seeds of bean, variety Echo Elit, were irradiated with a 300 Gy dose of X-ray irradiation (120 kV; 4.5 mA). In order to characterize repair and recovery at plant level, the biological production and photosynthetic pigments of the plants during ontogenesis in vivo and changes in their electric capacitance were continuously monitored and recorded via a computer-aided and -controlled data acquisition system. According to the data obtained, the repair in the biosynthesis of photosynthetic pigments will have been completed by the beginning of flowering. It may be assumed from the capacitance measurements made at 11 a.m. According to this postulation the process of repairing X-ray injuries might be finished by the beginning of pod formation without the plants actually recovering. (author)

  4. Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Ali [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey)], E-mail: alibabam2001@yahoo.com; Tatar, Abdulgani; Oztas, Sitki [Department of Genetics, Faculty of Medicine, Ataturk University, 25240 Erzurum (Turkey); Seven, Bedri; Varoglu, Erhan [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey); Yesilyurt, Ahmet [Department of Genetics, Faculty of Medicine, Ataturk University, 25240 Erzurum (Turkey); Ayan, Arif Kursad [Department of Nuclear Medicine, Faculty of Medicine, Medical School, Ataturk University, Erzurum (Turkey)

    2009-07-15

    Introduction: Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). Methods: The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. Results: In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). Conclusions: This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

  5. Evaluation of the genotoxic effects of chronic low-dose ionizing radiation exposure on nuclear medicine workers

    International Nuclear Information System (INIS)

    Sahin, Ali; Tatar, Abdulgani; Oztas, Sitki; Seven, Bedri; Varoglu, Erhan; Yesilyurt, Ahmet; Ayan, Arif Kursad

    2009-01-01

    Introduction: Nuclear medicine workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation may have damaging effects on chromosomes. In the present study, we investigated the genotoxic effects of ionizing radiation on nuclear medicine workers. We used two different indicators of genotoxicity methods: sister chromatid exchange (SCE) and micronucleus (MN). Methods: The present research was carried out using 21 nuclear medicine workers (11 females and 10 males) during two periods: during normal working conditions and after a 1-month vacation. The radiation dose varied from 1.20 to 48.56 mSv, which accumulated during the occupational exposure time between two vacations. Peripheral blood samples were taken from each subject for two distinct lymphocyte cultures (SCE and MN) in each period. Results: In nearly all subjects, SCE values increased significantly during radiation exposure compared to the postvacation period (P<.05). Similarly, MN frequencies in most of the subjects increased significantly during radiation exposure compared to the postvacation period (P<.05). Conclusions: This study revealed that both SCE and MN frequencies in most of the subjects were significantly higher during exposure to ionizing radiation than after a 1-month vacation period. However, this genotoxic effect was reversible in most of the subjects.

  6. On the development of neoplasma in dogs after chronic gamma-irradiation at a low dose rate

    International Nuclear Information System (INIS)

    Yakovleva, V.I.

    1978-01-01

    In order to estimate end effects of chronic prolonged gamma irradiation of dogs, an exposure of 80 animals to irradiation was terminated and they were followed up closely. Out of 80 animals 30 dogs (Ist series) were irradiated for 3 years and 50 dogs (2 series) for 6 years. The dogs were exposed to irradiation at doses of 21 to 190 rad per year. Out of the total number of animals 22 dogs died. Post-mortem examinations showed neoplasms in 13 animals (7 malignant and 12 benign neoplasms). The highest number of tumors developed in dogs of the 2 series (10 out of 11) one-two years after irradiation (6 malignant tumors-malignant pheochro--mocytoma of adrenals; malignant adenoma of the hypophysis: polymorphocellular sarcoma of the liver; leucomyosarcoma of the uterus; blader cancer; breast cancer; and 10 benign tumors-pancreatic adenoma; liver angioma; 2 papillary adenomas of the prostate; 3 renal adenomas; lipoma; polyps of the gall-bladder). Animals of the 1-st series displayed 3 neoplasms (1 malignant tumor-bladder tumor and 2 benign tumors-liver hepatoma and spleen angioma) 4-5 years after irradiation

  7. A study on relation between nitroxyl radical reduction potency and X-ray irradiation on mouse lung using L-band electron spin resonance

    International Nuclear Information System (INIS)

    Taneike, Makoto; Sho, Keizen; Morita, Rikushi

    1999-01-01

    Changes in nitroxy radical reduction potency (''reduction potency''), caused by different doses and different number of fractions of X-ray irradiation were studied using a L-band electron spin resonance system on mouse lungs into which 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (hydroxy-TEMPO) was introduced through the trachea. The ''reduction potency'' lineally decreased as the irradiation dose increased from 1.0 to 5.0 Gy, but no further decrease was observed at higher doses of 7.5 and 10 Gy. The reduction potency'' dropped at 20 min after each irradiation, but it recovered to the control levels after 1 week in all 3 groups of single dose of 10 Gy, 3 fractions and 5 fractions in a similar manner. Although the levels of the ''reduction potency'' were kept high in the groups of fractionated irradiation through 1-4 weeks after irradiation, the levels dropped again in the single dose group at 1 week and the levels were kept significantly low until 4 weeks after irradiation. suggesting that the fractionation of X-ray irradiation would also be effective to prevent the deterioration of the ''reduction potency''. Pre-treatment with sufficient ascorbic acid inhibited the lowering effects of radiation on the ''reduction potency'' in a dose dependent manner. Furthermore the levels of the reduction potency'' ever elevated higher than those of controls with the large amount of ascorbic acid of 750 mg/kg or more, suggesting that the large amounts of ascorbic acid could prevent the adverse effects associated with radiation therapy for the lung malignancy. (author)

  8. Influence of different iodinated contrast media on the induction of DNA double-strand breaks after in vitro X-ray irradiation.

    Science.gov (United States)

    Deinzer, Christoph K W; Danova, Daniela; Kleb, Beate; Klose, Klaus J; Heverhagen, Johannes T

    2014-01-01

    The objective of this work was to examine differences in DNA double-strand break induction in peripheral blood lymphocytes after in vitro X-ray irradiation between iodinated contrast agents. Four different iodinated X-ray contrast agents--three of them with two different iodine concentrations--and mannitol (negative control; concentration of 150 mg mannitol per ml blood) were pipetted into blood samples so that there was a concentration of 0, 7.5 or 15 mg of iodine per ml blood in the samples. Negative controls without contrast medium (0 mg of iodine per ml blood) were also processed for every irradiation dose. The tubes were exposed to 0, 20 or 500 mGy in vitro X-ray irradiation. After that, the lymphocytes were separated by using density-gradient centrifugation. Fluorescence microscopy was applied to determine the average number of γH2AX-foci per lymphocyte in the presence or absence of different contrast media or mannitol. Differences in the number of γH2AX-foci were statistically analysed by one-way ANOVA and post-hoc Tukey's honestly significant difference test. Iodinated contrast agents led to a statistically significant increase in DNA double-strand breaks after in vitro irradiation. This effect increased statistically significant with rising radiation dose and appeared independent of the contrast agent used (iopromid, iodixanol, iomeprol, iopamidol). A statistically significant difference in DNA damage between the different tested contrast agents was not found. Therefore, the increase in DNA double-strand breaks depends solely on the amount of iodine applied. For evaluation of clinical consequences, our findings could be tested in further animal studies. Copyright © 2014 John Wiley & Sons, Ltd.

  9. Low dose X -ray effects on catalase activity in animal tissue

    Science.gov (United States)

    Focea, R.; Nadejde, C.; Creanga, D.; Luchian, T.

    2012-12-01

    This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, pbonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

  10. Examination of Chronic Smoking Behavior and Eligibility for Low-Dose Computed Tomography for Lung Cancer Screening Among Older Chinese Male Smokers.

    Science.gov (United States)

    Li, Chien-Ching; Matthews, Alicia K; Dong, XinQi

    2017-07-01

    Low-dose computed tomography lung cancer (LDCT) screening is an effective way to decrease lung cancer mortality. Both Medicare and private insurers offer coverage of LDCT screening to beneficiaries who are at high risk of developing lung cancer. In this study, we examined rates and predictors of chronic smoking behavior and eligibility for coverage of LDCT screening among older Chinese men living in the greater Chicago area. Data were obtained from the Population Study of Chinese Elderly in Chicago, a population-based survey of community-dwelling, older Chinese adults in the Chicago metropolitan area. Eligibility criteria according to Centers of Medicare and Medicaid Services (CMS) and U.S. Preventive Services Task Force (USPSTF) for LDCT screening were used. Multivariate logistic regression was conducted to determine predictors of chronic smoking behavior which was operationalized as meeting criteria for LDCT screening. A quarter of the sample were current smokers and 42.5% reported a prior history of smoking. Eighteen percent and 22% of older Chinese men met the eligibility criteria for appropriateness for CMS and USPSTF LDCT screening, respectively. Furthermore, education, marital status, and number of children were significantly associated with chronic smoking behavior. Older Chinese men with chronic smoking behavior are at high risk of developing lung cancer and nearly one in five meet eligibility for LDCT screening. Increased outreach and education regarding early detection of lung cancer and smoking cessation are needed for this vulnerable and high-risk population. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Low dose epidemiologic studies

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    In this chapter the BEIR committee has reviewed low-dose irradiation studies since the BEIR III report. They have considered the carcinogenic effectiveness of low-LET in populations exposed to radiation from a number of different sources: diagnostic radiography; fallout from nuclear weapons testing; nuclear installations; radiation in the workplace and high levels of natural background radiation

  12. Iterative reconstruction technique vs filter back projection: utility for quantitative bronchial assessment on low-dose thin-section MDCT in patients with/without chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Hisanobu; Seki, Shinichiro; Sugimura, Kazuro [Kobe University Graduate School of Medicine, Division of Radiology, Department of Radiology, Kobe, Hyogo (Japan); Ohno, Yoshiharu; Nishio, Mizuho; Matsumoto, Sumiaki; Yoshikawa, Takeshi [Kobe University Graduate School of Medicine, Advanced Biomedical Imaging Research Centre, Kobe (Japan); Kobe University Graduate School of Medicine, Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe (Japan); Sugihara, Naoki [Toshiba Medical Systems Corporation, Ohtawara, Tochigi (Japan)

    2014-08-15

    The aim of this study was to evaluate the utility of the iterative reconstruction (IR) technique for quantitative bronchial assessment during low-dose computed tomography (CT) as a substitute for standard-dose CT in patients with/without chronic obstructive pulmonary disease. Fifty patients (mean age, 69.2; mean % predicted FEV1, 79.4) underwent standard-dose CT (150mAs) and low-dose CT (25mAs). Except for tube current, the imaging parameters were identical for both protocols. Standard-dose CT was reconstructed using filtered back-projection (FBP), and low-dose CT was reconstructed using IR and FBP. For quantitative bronchial assessment, the wall area percentage (WA%) of the sub-segmental bronchi and the airway luminal volume percentage (LV%) from the main bronchus to the peripheral bronchi were acquired in each dataset. The correlation and agreement of WA% and LV% between standard-dose CT and both low-dose CTs were statistically evaluated. WA% and LV% between standard-dose CT and both low-dose CTs were significant correlated (r > 0.77, p < 0.00001); however, only the LV% agreement between SD-CT and low-dose CT reconstructed with IR was moderate (concordance correlation coefficient = 0.93); the other agreement was poor (concordance correlation coefficient <0.90). Quantitative bronchial assessment via low-dose CT has potential as a substitute for standard-dose CT by using IR and airway luminal volumetry techniques. circle Quantitative bronchial assessment of COPD using low-dose CT is possible. (orig.)

  13. MiR-34a is up-regulated in response to low dose, low energy X-ray induced DNA damage in breast cells

    International Nuclear Information System (INIS)

    Stankevicins, Luiza; Almeida, Carlos Eduardo de; Moura Gallo, Claudia Vitoria de; Almeida da Silva, Ana Paula; Ventura dos Passos, Flavia; Santos Ferreira, Evelin dos; Menks Ribeiro, Maria Cecilia; G David, Mariano; J Pires, Evandro; Ferreira-Machado, Samara Cristina; Vassetzky, Yegor

    2013-01-01

    MicroRNAs are non-coding RNAs involved in the regulation of gene expression including DNA damage responses. Low doses of low energy X-ray radiation, similar to those used in mammographic exams, has been described to be genotoxic. In the present work we investigated the expression of miR-34a; a well described p53-regulated miRNA implicated in cell responses to X-ray irradiation at low doses. Non-cancerous breast cell line MCF-10A and cancerous T-47D and MCF-7 cell lines were submitted to a low-energy X-ray irradiation (ranging from 28–30 Kv) using a dose of 5 Gy. The expression level of miR-34a, let-7a and miR-21 was assessed by qRT-PCR at 4 and 24 hours post-irradiation. DNA damage was then measured by comet assay and micronuclei estimation in MCF-10A and MCF-7 cell lines, where an increase of miR-34a levels could be observed after irradiation. The rate of apoptotic cells was estimated by nuclear staining and fluorescence microscopy. These experiments were also performed at low doses (3; 12 and 48 mGy) in MCF-10A and MCF-7 cell lines. We have observed an increase in miR-34a expression 4 hours post-irradiation at 5 Gy in MCF-10A and MCF-7 cell lines while its level did not change in T-47D, a breast cancer cell line bearing non-functional p53. At low doses, miR-34a was up-regulated in non-tumoral MCF-10A to a higher extent as compared to MCF-7. MiR-34a levels decreased 24 hours post-irradiation. We have also observed DNA damage and apoptosis at low-energy X-ray irradiation at low doses and the high dose in MCF-10A and MCF-7 4 and 24 hours post-irradiation relative to the mock control. Low energy X-ray is able to promote DNA strand breaks and miR-34a might be involved in cell responses to low energy X-ray DNA damage. MiR-34a expression correlates with X-ray dose, time after irradiation and cell type. The present study reinforces the need of investigating consequences of low dose X-ray irradiation of breast cells

  14. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  15. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  16. Protective effects of the fermented milk Kefir on X-ray irradiation-induced intestinal damage in B6C3F1 mice

    International Nuclear Information System (INIS)

    Teruya, Kiichiro; Nakamichi, Noboru; Shirahata, Sanetaka; Myojin-Maekawa, Yuki; Shimamoto, Fumio; Watanabe, Hiromitsu; Tokumaru, Koichiro; Tokumaru, Sennosuke

    2013-01-01

    Gastrointestinal damage associated with radiation therapy is currently an inevitable outcome. The protective effect of Kefir was assessed for its usefulness against radiation-induced gastrointestinal damage. A Kefir supernatant was diluted by 2- or 10-fold and administered for 1 week prior to 8 Gray (Gy) X-ray irradiation at a dose rate of 2 Gy/min, with an additional 15d of administration post-irradiation. The survival rate of control mice with normal drinking water dropped to 70% on days 4 through 9 post-irradiation. On the other hand, 100% of mice in the 10- and 2-fold-diluted Kefir groups survived up to day 9 post-irradiation (p<0.05 and p<0.01, respectively). Examinations for crypt regeneration against 8, 10 and 12 Gy irradiation at a dose rate of 4 Gy/min revealed that the crypt number was significantly increased in the mice administered both diluted Kefir solutions (p<0.01 for each). Histological and immunohistochemical examinations revealed that the diluted Kefir solutions protected the crypts from radiation, and promoted crypt regeneration. In addition, lyophilized Kefir powder was found to significantly recover the testis weights (p<0.05), but had no effects on the body and spleen weights, after 8 Gy irradiation. These findings suggest that Kefir could be a promising candidate as a radiation-protective agent. (author)

  17. Charge recombination process in X-ray irradiated pyrene-doped polystyrene as studied by optically detected electron spin resonance and magnetic field dependence of the recombination fluorescence

    International Nuclear Information System (INIS)

    Okazaki, Masaharu; Tai, Yutaka; Toriyama, Kazumi

    1993-01-01

    The optically-detected ESR (ODESR) spectrum and magnetic field dependence on recombination fluorescence were observed for X-ray irradiated pyrene-doped polystyrene at temperatures of 242-348 K. The ODESR intensity as a function of the pyrene concentration, 0.1-8.9 wt%, showed an unusual minimum at about 1.0%. Two phases were separated in the magnetic field dependence of the fluorescence: one was sharp and saturates at fields of over 50 mT, while the other was broad with a dip at around 60-150 mT. The cause of this dip was naturally attributed to the ST -1 level crossing. The sharp magnetic field effect also showed a minimum at around a concentration of 1.0 wt%. These novel findings have been interpreted using a recombination model modified from the previous one for pyrene-doped ethylene-propylene rubber and polyethylene. The essential points of the present model are: (1) although electron hopping within the polystyrene molecule is rapid, electron transfer at the last step of recombination between the polystyrene anion and the pyrene cation proceeds at a moderate rate; (2) the hole-transfer rate in the polymer chain is moderate; (3) electron hopping between the doped pyrene molecules is very much dependent on the concentration; (4) hole hopping between the pyrenes is inhibited. (author)

  18. DUOX 1 is induced in human thyroid cells submitted to X-Ray irradiation and is responsible for the bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Boufraqech, M.; Chevallier Lagente, O.; Weyemi, U.; Talbot, M.; Al Ghuzlan, A.; Courtin, F.; Bidart, J.M.; Schlumberger, M.; Dupuy, C. [UMR 8200 CNRS, Institut Gustave Roussy, Villejuit (France); Ameziane el Hassani, R. [UBRM, Centre National de l' Energie, des Sciences et des Techniques Nucleaires, Rabat (Morocco)

    2012-07-01

    Radiation-induced bystander effect is the mechanism by which cells that have not been directly exposed to ionizing radiation behave like exposed cells: they die or show chromosomal instability and other phenotypic abnormalities. Bystander cells may be either adjacent or at some distance from the exposed cells. Irradiated cells release soluble factors that can be transferred through cell culture medium to non-irradiated cells. These factors include cytokines and reactive oxygen species (ROS). The aim of this study was to identify the ROS generating system induced by X-ray irradiation of human thyroid cells that could be responsible for the bystander effect. Irradiation of human thyroid epithelial cells (HTori-3 cells) induced an extracellular production of H{sub 2}O{sub 2} after 4 days that was related to the radiation dose. Our study shows that radiation exposure increases DUOX-1 expression after several days, suggesting that this H{sub 2}O{sub 2} generating system could be responsible for the late bystander effect. This could have a potential importance for radiation risk assessment and for cancer radiotherapy

  19. Exploring the doping dependence of the Mott transition on X-ray irradiated crystals of {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, Sebastian; Tutsch, Ulrich; Naji, Ammar; Lang, Michael [Physikalisches Institut, Goethe-Universitaet Frankfurt (Germany); Sasaki, Takahiko [Institute for Materials Research, Tohoku University, Aoba-ku, Sendai, Miyagi (Japan)

    2011-07-01

    The quasi two-dimensional organic charge-transfer salt {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl exhibits a rich pressure vs. temperature phase diagram, including Mott-insulating and metallic phases separated by a first order transition line. By applying moderate pressures of {proportional_to}30 MPa (300 bar), the ratio of the kinetic energy to the onsite Coulomb repulsion t/U can be changed sufficiently to cross this phase transition line. Our objective is to study the effect of carrier doping and the accompanying changes of the first-order transition line and its second-order critical endpoint. We used X-ray irradiation to introduce charge carriers into the material, doping it away from half filling. We present resistivity data for the temperature range 5 K

  20. PSK, a biological response modifier, modifies p53 expression, mitosis and apoptosis in X-ray irradiated mouse embryos. Possible cellular mechanism of the anti-teratogenic effect

    International Nuclear Information System (INIS)

    Kagohashi, Yukiko; Naora, Hiroyuki; Otani, Hiroki

    2002-01-01

    We previously showed that PSK, a biological response modifier, suppressed X-ray irradiation induced ocular anomalies in mouse embryos. In the present study, in mouse embryos irradiated at E7.5, PSK, when administered immediately after irradiation, suppressed mitosis and increased apoptosis as compared with embryos not treated with PSK at 12 hrs after irradiation. In the irradiated embryos, p53, which is normally expressed at a high level in early embryos, increased at 6 hrs and decreased at 12 hrs after irradiation. In the irradiated and PSK-treated embryos, the p53 level did not change at 6 hrs, increased at 12 hrs and decreased at 24 hrs after irradiation. This timing of PSK-induced delayed increase of p53 coincided with that of the PSK-induced decrease in mitosis and increase in apoptosis. These results suggested that PSK modified the p53 level and affected cell proliferation and apoptosis, which might contribute to the suppression of teratogenesis. (author)

  1. Effect of Hind-Limb Suspension and X-Ray Irradiation on the Mechanical and Chemical Properties of Rat Femur and Tibia Bones

    Science.gov (United States)

    Heacox, Hayley; Hill, Brent; Mehta, Rahul; Barajas, Jordan; Freyaldenhoven, Sidney; Dobretsov, Max; Chowdhury, Parimal

    It is known that space conditions such as microgravity and cosmic radiation have detrimental effects on the skeletal system of humans, such as decreased bone mineral density. This research studies the changes in mechanical properties, elasticity, and chemical properties, calcium and phosphorus content, of rat femur and tibia bones when exposed to hind-limb suspension and x-ray irradiation, simulated microgravity and cosmic radiation. It is hypothesized that if microgravity and cosmic radiation lead to decreased bone mineral density, then these conditions will produce weakened bones, lower elastic moduli and abnormal concentrations of calcium and phosphorus, as compared to bones not subject to these conditions. A technique known as three-point bending was employed to estimate the Young's (elastic) modulus for the leg bones. To investigate the chemical nature of the bones, a Scanning Electron Microscope (SEM) was utilized to take cross-sectional images and to perform energy dispersive x-ray spectroscopy. Ultimately, the results produced by this research will aid in quantifying the effects of spaceflight and may be used in developing a treatment to counteract such effects. This work supported by a RID and CRP Grant from Arkansas Space Grant Consortium.

  2. Room temperature Q-band electron magnetic resonance study of radicals in X-ray-irradiated L-threonine single crystals

    International Nuclear Information System (INIS)

    Vanhaelewyn, Gauthier; Vrielinck, Henk; Callens, Freddy

    2014-01-01

    In the past, decennia radiation-induced radicals were successfully identified by electron magnetic resonance (EMR) in several solid-state amino acids and sugars. The authors present a room temperature (RT) EMR study of the stable radicals produced by X-ray-irradiation in the amino acid L-threonine (CH 3 CH(OH)CH(NH3 + )COO - ). Its chemical structure is similar to that of the well-known dosimetric material L-alanine (CH 3 CH(NH3 + )COO - ), and radiation defects in L-threonine may straightforwardly be compared with the extensively studied L-alanine radicals. The hyperfine coupling tensors of three different radicals were determined at RT using electron nuclear double resonance. These results indicate that the two most abundant radicals share the same basic structure CH 3 .C(OH)CH(NH3 + )COO - , obtained by H-abstraction, but are stabilised in slightly different conformations. The third radical is most probably obtained by deamination (CH 3 CH(OH).CHCOO - ), similar in structure to the stable alanine radical. (authors)

  3. Influence of neuraminidase and X-ray irradiation (2 Gy and 8 Gy) on microvilli and membrane invaginations of Ehrlich ascites tumor cells in monolayer culture

    International Nuclear Information System (INIS)

    Laudenbach, G.; Baganz, O.; Pfab, R.; Hess, F.; Schachtschabel, D.O.

    1987-01-01

    A monolayer culture (Eagle basal medium plus 10% of fetal calf serum) of Ehrlich ascites tumor cells was exposed to X-radiation with 2 Gy and 8 Gy and treated with Vibrio cholerae neuraminidase alone or combined with sublethal X-ray irradiation (2 Gy). Pictures of the Ehrlich ascites tumor cells taken with the electron microscope were investigated in order to find out any cell surface modifications due to membrane invaginations and microvilli. The results showed that the rate of microvilli as well as that of membrane invaginations became higher with the increasing X-ray dose (2 Gy; 8 Gy). Following to neuraminidase treatment there was a considerable augmentation of membran invaginations as compared to control cells, whereas the number of microvilli was slightly reduced. As it has been already described before, the influence of neuraminidase produced an increased endocytosis activity and a strengthening of the cytoskeleton. Combined treatment with neuraminidase and sublethal X-radiation (2 Gy) caused a higher rate of membrane invaginations than each method alone; the number of microvilli was slightly increased by combined treatment. The conclusion is drawn that these structure modifications are due to reparation processes induced by radiation on the one hand and to an enzymic action of neuraminidase on the cell surface on the other hand. (orig.) [de

  4. N-Acetyl Cysteine does not prevent liver toxicity from chronic low dose plus sub-acute high dose paracetamol exposure in young or old mice

    Science.gov (United States)

    Kane, Alice-Elizabeth; Huizer-Pajkos, Aniko; Mach, John; McKenzie, Catriona; Mitchell, Sarah-Jayne; de Cabo, Rafael; Jones, Brett; Cogger, Victoria; Le Couteur, David G; Hilmer, Sarah-Nicole

    2016-01-01

    Paracetamol is an analgesic commonly used by people of all ages, which is well documented to cause severe hepatotoxicity with acute over-exposures. The risk of hepatotoxicity from non-acute paracetamol exposures is less extensively studied, and this is the exposure most common in older adults. Evidence on the effectiveness of N-acetyl cysteine (NAC) for non-acute paracetamol exposures, in any age group, is lacking. This study aimed to examine the effect of long-term exposure to therapeutic doses of paracetamol and sub-acute paracetamol over-exposure, in young and old mice, and to investigate whether NAC was effective at preventing paracetamol hepatotoxicity induced by these exposures. Young and old male C57BL/6 mice were fed a paracetamol-containing (1.33g/kg food) or control diet for 6 weeks. Mice were then dosed orally 8 times over 3 days with additional paracetamol (250mg/kg) or saline, followed by either one or two doses of oral NAC (1200mg/kg) or saline. Chronic low-dose paracetamol exposure did not cause hepatotoxicity in young or old mice, measured by serum alanine aminotransferase (ALT) elevation, and confirmed by histology and a DNA fragmentation assay. Sub-acute paracetamol exposure caused significant hepatotoxicity in young and old mice, measured by biochemistry (ALT) and histology. Neither a single nor double dose of NAC protected against this toxicity from sub-acute paracetamol in young or old mice. This finding has important clinical implications for treating toxicity due to different paracetamol exposure types in patients of all ages, and implies a need to develop new treatments for sub-acute paracetamol toxicity. PMID:26821200

  5. No adaptive response is induced by chronic low-dose radiation from Ra-226 in the CHSE/F fish embryonic cell line and the HaCaT human epithelial cell line

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaopei, E-mail: shix22@mcmaster.ca; Mothersill, Carmel; Seymour, Colin

    2016-11-15

    Purpose: To determine whether chronic low-dose α-particle radiation from Ra-226 over multiple cell generations can lead to an adaptive response in CHSE/F fish embryonic cells or HaCaT human epithelial cells receiving subsequent acute high-dose γ-ray radiation. Methods: CHSE/F and HaCaT cells were exposed to very low doses of Ra-226 in medium for multiple generations prior to being challenged by a higher dose γ-ray radiation. The clonogenic assay was used to test the clonogenic survival of cells with or without being pretreated by radiation from Ra-226. Results: In general, pretreatment with chronic radiation has no significant influence on the reaction of cells to the subsequent challenge radiation. Compared to unprimed cells, the change in clonogenic survival of primed cells after receiving challenge radiation is mainly due to the influence of the chronic exposure, and there's little adaptive response induced. However at several dose points, pretreatment of CHSE/F fish cells with chronic radiation resulted in a radiosensitive response to a challenge dose of γ-ray radiation, and pretreatment of HaCaT cells resulted in no effect except for a slightly radioresistant response to the challenge radiation which was not significant. Conclusion: The results suggest that chronic low-dose radiation is not effective enough to induce adaptive response. There was a difference between human and fish cells and it may be important to consider results from multiple species before making conclusions about effects of chronic or low doses of radiation in the environment. The term “radiosensitive” or “adaptive” make no judgment about whether such responses are ultimately beneficial or harmful. - Highlights: • No obvious adaptive response is induced by chronic low-dose radiation from Ra-226. • Priming radiation from Ra-226 sensitized CHSE/F cells to the challenge radiation. • Linear model is inconsistent with current work using chronic low-dose radiation.

  6. Automated assessment of aortic and main pulmonary arterial diameters using model-based blood vessel segmentation for predicting chronic thromboembolic pulmonary hypertension in low-dose CT lung screening

    Science.gov (United States)

    Suzuki, Hidenobu; Kawata, Yoshiki; Niki, Noboru; Sugiura, Toshihiko; Tanabe, Nobuhiro; Kusumoto, Masahiko; Eguchi, Kenji; Kaneko, Masahiro

    2018-02-01

    Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by obstruction of the pulmonary vasculature by residual organized thrombi. A morphological abnormality inside mediastinum of CTEPH patient is enlargement of pulmonary artery. This paper presents an automated assessment of aortic and main pulmonary arterial diameters for predicting CTEPH in low-dose CT lung screening. The distinctive feature of our method is to segment aorta and main pulmonary artery using both of prior probability and vascular direction which were estimated from mediastinal vascular region using principal curvatures of four-dimensional hyper surface. The method was applied to two datasets, 64 lowdose CT scans of lung cancer screening and 19 normal-dose CT scans of CTEPH patients through the training phase with 121 low-dose CT scans. This paper demonstrates effectiveness of our method for predicting CTEPH in low-dose CT screening.

  7. Basic study on low dose radiation effect: SOD activity of immune organs and hemogram in rats

    International Nuclear Information System (INIS)

    Yamaoka, Kiyonori; Kaneko, Ichiro; Mizutani, Takeo; Nakano, Kazushiro; Edamatsu, Rei; Mori, Akitane.

    1989-01-01

    We examined the effect of low dose radiation on SOD activities of immune organs such as thymus, spleen, bone marrow in rats and hematological findings changes. Animals were exposed to radiation in a wholebody fashion, 4 hours before sacrifice. SOD activities in thymus and bone marrow cells from the rats X-ray irradiated at doses of 0.25∼0.50 Gy/10 min were enhanced in comparison with those of non-irradiated rats. The enhancement was also observed in spleen cells obtained from group of rats irradiated at 0.05 Gy/10 min. Radiation exposure with over 0.50 Gy/10 min gave rats inhibitory responses in those immune organs. The changes in homogram were not observed with γ-ray exposure of less than 0.10 Gy/10 min. (author)

  8. Suppression of experimental tractional retinal detachment by low-dose radiation therapy

    International Nuclear Information System (INIS)

    Meredith, T.A.; Ficker, L.; Stevens, R.; Olkowski, Z.; Anderson, M.; Hartmann, J.; Crocker, I.

    1988-01-01

    We used a standardized model of traction retinal detachment (TRD) created by cellular membranes in the rabbit to test the effects of low-dose radiation therapy in suppressing TRD. The vitreous and lens were removed from pigmented rabbits, and homologous conjunctival fibroblasts were grown in cell culture. After resolution of postoperative inflammation, 50,000 fibroblasts in 0.1 mL of culture fluid were injected into the vitreous cavity. Ten eyes were maintained as controls. Nineteen eyes received 6 Gy (600 rad) of x-ray irradiation one to three hours after cellular injection. Eyes were monitored weekly for three weeks with indirect ophthalmoscopy. Seven (70%) of ten control eyes developed TRD at one week; no additional TRDs were noted at weeks 2 and 3. Significantly smaller numbers of irradiated eyes developed TRD: at week 1, two (11%) of 19; at week 2, five (28%) of 18; and at week 3, five (29%) of 17

  9. Generation of a panel of somatic cell hybrids containing unselected fragments of human chromosome 10 by X-ray irradiation and cell fusion: Application to isolating the MEN2A region in hybrid cells

    International Nuclear Information System (INIS)

    Goodfellow, P.J.; Povey, S.; Nevanlinna, H.A.; Goodfellow, P.N.

    1990-01-01

    We have used X-ray irradiation and cell fusion to generate somatic cell hybrids containing fragments of human chromosome 10. Our experiments were directed towards isolating the region of the MEN2A gene in hybrids and to use those as the source of DNA for cloning and mapping new markers from near the MEN2A locus. A number of hybrid clones containing human sequences that are tightly linked to the MEN2A gene were identified. Some 25% of our hybrids, however, proved to contain more than one human chromosome 10-derived fragment or showed evidence of deletions and/or rearrangements. A detailed analysis of the human content of X-ray irradiation hybrids is required to assess the integrity and number of human fragments retained. Despite retention of multiple human-derived fragments, these hybrids will prove useful as cloning and mapping resources

  10. Impact of low-dose chronic exposure to Bisphenol A (BPA) on adult male zebrafish adaption to the environmental complexity: Disturbing the color preference patterns and reliving the anxiety behavior.

    Science.gov (United States)

    Li, Xiang; Sun, Ming-Zhu; Li, Xu; Zhang, Shu-Hui; Dai, Liang-Ti; Liu, Xing-Yu; Zhao, Xin; Chen, Dong-Yan; Feng, Xi-Zeng

    2017-11-01

    The extensive usage of xenobiotic endocrine disrupting chemicals (XEDCs), such as Bisphenol A (BPA), has created obvious threat to aquatic ecosystems worldwide. Although a comprehensive understanding of the adverse effect of BPA on behaviors and physiology have been proven, the potential impact of low-dose BPA on altering the basic ability of aquatic organism in adapting to the surrounded complex environment still remains elusive. In this research, we report that treatment of adult male zebrafish with chronic (7 weeks) low-dose (0.22 nM-2.2 nM) BPA, altered the ability in adapting the complex environment by disturbing the natural color preference patterns. In addition, chronic 50 ng/L (0.22 nM) BPA exposure alleviated the anxiety behavior of male zebrafish confronted with the novel environment by enhancing the preference towards light in the light/dark preference test. This phenotype was associated with less expression of serotonin (5-TH) in the hypothalamus and the down-regulation of tyrosine hydroxylase (TH) in brain tissues. As such, our results show that low-dose BPA remnant in surface waters altered zebrafish behavior that are known to have ecological and evolutionary consequences. Here we reported that the impact of chronic low-dose BPA exposure on the basic capability of zebrafish to adapt to the environmental complexity. Specifically, BPA at low concentration, under the environmental safety level and 3000-fold lower than the accepted human daily exposure, interfered with the ability to discriminate color and alleviate anxiety induced by the novel environment, which finally altered the capability of male zebrafish to adapt to the environmental complexity. These findings revealed the ecological effect of low-dose BPA and regular BPA concentration standard are not necessarily safe. The result also provided the consideration of retuning the hazard concentration level of BPA. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. THE RESPONSE OF METAL-RICH GAS TO X-RAY IRRADIATION FROM A MASSIVE BLACK HOLE AT HIGH REDSHIFT: PROOF OF CONCEPT

    Energy Technology Data Exchange (ETDEWEB)

    Aykutalp, A.; Meijerink, R.; Spaans, M. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700-AV Groningen (Netherlands); Wise, J. H., E-mail: aycin.aykutalp@sns.it, E-mail: meijerink@astro.rug.nl, E-mail: spaans@astro.rug.nl, E-mail: jwise@physics.gatech.edu [Center for Relativistic Astrophysics, Georgia Institute of Technology, 837 State Street, Atlanta, GA 30332 (United States)

    2013-07-01

    Observational studies show that there is a strong link between the formation and evolution of galaxies and the growth of their supermassive black holes. However, the underlying physics behind this observed relation is poorly understood. In order to study the effects of X-ray radiation on black hole surroundings, we implement X-ray-dominated region physics into Enzo and use the radiation transport module Moray to calculate the radiative transfer for a polychromatic spectrum. In this work, we investigate the effects of X-ray irradiation, produced by a central massive black hole (MBH) with a mass of M = 5 Multiplication-Sign 10{sup 4} M{sub Sun }, on ambient gas with solar and zero metallicity. We find that in the solar metallicity case, the energy deposition rate in the central region ({<=}20 pc) is high due to the high opacity of the metals. Hence, the central temperatures are on the order of 10{sup 5}-10{sup 7} K. Moreover, due to the cooling ability and high intrinsic opacity of solar metallicity gas, column densities of 10{sup 24} cm{sup -2} are reached at a radius of 20 pc from the MBH. These column densities are about three orders of magnitudes higher than in the zero metallicity case. Furthermore, in the zero metallicity case, an X-ray-induced H II region is already formed after 5.8 Myr. This causes a significant outflow of gas ({approx}8 Multiplication-Sign 10{sup 6} M{sub Sun }) from the central region; the gas reaches outflow velocities up to {approx}100 km s{sup -1}. At later times, {approx}23 Myr after we insert the MBH, we find that the solar metallicity case also develops an X-ray-induced H II region, but it is delayed by {approx}17 Myr compared to the zero metallicity case.

  12. SOFT X-RAY IRRADIATION OF H{sub 2}S ICE AND THE PRESENCE OF S{sub 2} IN COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Escobar, A.; Munoz Caro, G. M. [Centro de Astrobiologia (CSIC-INTA), Carretera de Ajalvir, km 4, Torrejon de Ardoz, 28850 Madrid (Spain); Ciaravella, A.; Candia, R.; Micela, G. [INAF-Osservatorio Astronomico di Palermo, P.za Parlamento 1, 90134 Palermo (Italy); Cecchi-Pestellini, C., E-mail: munozcg@cab.inta-csic.es [INAF-Osservatorio Astronomico di Cagliari, Strada n.54, Loc. Poggio dei Pini, I-09012 Capoterra (Canada) (Italy)

    2012-06-01

    Little is known about the effects of X-rays in interstellar ices. To understand the sulfur depletion in dense clouds and the presence of S{sub 2} in comets, we simulated experimentally the soft X-ray processing (0.3 keV) of H{sub 2}S ice for the first time. Experiments were performed under ultrahigh vacuum conditions at 8 K using infrared and quadrupole mass spectrometry to monitor the solid and gas phases, respectively. A UV irradiation experiment using a similar dose was made for comparison. After X-ray irradiation, an infrared absorption appears near 4.0 {mu}m which is attributed to H{sub 2}S{sub 2} formation in the ice. This identification is also supported by the desorption at 133 K of m/z 66, 65, 64, corresponding to the mass fragments of H{sub 2}S{sub 2}. The H{sub 2}S{sub 2} species is expected to be present in interstellar and cometary ices that were processed by X-rays. Further irradiation leads to dissociation of this molecule forming S{sub 2} and larger S-molecules up to S{sub 8}, which may explain the depletion of sulfur in dense clouds. CS{sub 2} was so far the parent molecule proposed for S{sub 2} formation in comets. But the abundance of H{sub 2}S{sub 2}, formed by irradiation of pure H{sub 2}S or H{sub 2}S in an H{sub 2}O-ice matrix, should be larger than that of CS{sub 2} in the ice, the latter requiring a carbon source for its formation. Based on our experimental results, we propose that S{sub 2} in comets could be formed by dissociation of H{sub 2}S{sub 2} in the ice.

  13. Prediction of improvement in global left ventricular function in patients with chronic coronary artery disease and impaired left ventricular function: rest thallium-201 SPET versus low-dose dobutamine echocardiography

    International Nuclear Information System (INIS)

    Pace, L.; Salvatore, M.; Perrone-Filardi, P.; Dellegrottaglie, S.; Prastaro, M.; Crisci, T.; Ponticelli, M.P.; Piscione, F.; Chiariello, M.; Storto, G.; Della Morte, A.M.

    2000-01-01

    Accurate assessment of myocardial viability permits selection of patients who would benefit from myocardial revascularization. Currently, rest-redistribution thallium-201 scintigraphy and low-dose dobutamine echocardiography are among the most used techniques for the identification of viable myocardium. Thirty-one consecutive patients (all men, mean age 60±8 years) with chronic coronary artery disease and reduced left ventricular ejection fraction (31%±7%) were studied. Rest 201 Tl single-photon emission tomography (SPET), low-dose dobutamine echocardiography and radionuclide angiography were performed before revascularization. Radionuclide angiography and echocardiography were repeated after revascularization. An a/dyskinetic segment was considered viable on 201 Tl SPET when tracer uptake was >65%, while improvement on low-dose dobutamine echocardiography was considered a marker of viability. Increase in global ejection fraction was considered significant at ≥5%. In identifying viable segments, rest 201 Tl SPET showed higher sensitivity than low-dose dobutamine echocardiography (72% vs 53%, P 201 Tl SPET in group 1 than in group 2 (2.6±1.9 vs 0.6±1.2, P 201 Tl SPET and post-revascularization changes in ejection fraction (r=0.52, P 201 Tl SPET had a higher sensitivity (82% vs 53%, P=0.07) and showed a trend towards higher accuracy and specificity (77% vs 58%, and 71% vs 64%, respectively) as compared with low-dose dobutamine echocardiography. In conclusion, these findings suggest that when severely reduced global function is present, rest 201 Tl SPET evaluation of viability is more accurate than low-dose dobutamine echocardiography for the identification of patients who will benefit most from revascularization. (orig.)

  14. Low-Dose Radiation Promotes Dendritic Cell Migration and IL-12 Production via the ATM/NF-KappaB Pathway.

    Science.gov (United States)

    Yu, Nan; Wang, Sinian; Song, Xiujun; Gao, Ling; Li, Wei; Yu, Huijie; Zhou, Chuanchuan; Wang, Zhenxia; Li, Fengsheng; Jiang, Qisheng

    2018-04-01

    For dendritic cells (DCs) to initiate an immune response, their ability to migrate and to produce interleukin-12 (IL-12) is crucial. It has been previously shown that low-dose radiation (LDR) promoted IL-12 production by DCs, resulting in increased DC activity that contributed to LDR hormesis in the immune system. However, the molecular mechanism of LDR-induced IL-12 production, as well as the effect of LDR on DC migration capacity require further elucidation. Using the JAWSII immortalized mouse dendritic cell line, we showed that in vitro X-ray irradiation (0.2 Gy) of DCs significantly increased DC migration and IL-12 production, and upregulated CCR7. The neutralizing antibody against CCR7 has been shown to abolish LDR-enhanced DC migration, demonstrating that CCR7 mediates LDR-promoting DC migration. We identified nuclear factor kappaB (NF-κB) as the central signaling pathway that mediated LDR-enhanced expression of IL-12 and CCR7 based on findings that 0.2 Gy X-ray irradiation activated NF-κB, showing increased nuclear p65 translocation and NF-κB DNA-binding activity, while an NF-κB inhibitor blocked LDR-enhanced expression of IL-12 and CCR7, as well as DC migration. Finally, we demonstrated that 0.2 Gy X-ray irradiation promoted ATM phosphorylation and reactive oxygen species generation; however, only the ATM inhibitor abolished the LDR-induced NF-κB-mediated expression of IL-12 and CCR7. Altogether, our data show that exposure to LDR resulted in a hormetic effect on DCs regarding CCR7-mediated migration and IL-12 production by activating the ATM/NF-κB pathway.

  15. Neural Plasticity Associated with Hippocampal PKA-CREB and NMDA Signaling Is Involved in the Antidepressant Effect of Repeated Low Dose of Yueju Pill on Chronic Mouse Model of Learned Helplessness

    Directory of Open Access Journals (Sweden)

    Zhilu Zou

    2017-01-01

    Full Text Available Yueju pill is a traditional Chinese medicine formulated to treat syndromes of mood disorders. Here, we investigated the therapeutic effect of repeated low dose of Yueju in the animal model mimicking clinical long-term depression condition and the role of neural plasticity associated with PKA- (protein kinase A- CREB (cAMP response element binding protein and NMDA (N-methyl-D-aspartate signaling. We showed that a single low dose of Yueju demonstrated antidepressant effects in tests of tail suspension, forced swim, and novelty-suppressed feeding. A chronic learned helplessness (LH protocol resulted in a long-term depressive-like condition. Repeated administration of Yueju following chronic LH remarkably alleviated all of depressive-like symptoms measured, whereas conventional antidepressant fluoxetine only showed a minor improvement. In the hippocampus, Yueju and fluoxetine both normalized brain-derived neurotrophic factor (BDNF and PKA level. Only Yueju, not fluoxetine, rescued the deficits in CREB signaling. The chronic LH upregulated the expression of NMDA receptor subunits NR1, NR2A, and NR2B, which were all attenuated by Yueju. Furthermore, intracerebraventricular administration of NMDA blunted the antidepressant effect of Yueju. These findings supported the antidepressant efficacy of repeated routine low dose of Yueju in a long-term depression model and the critical role of CREB and NMDA signaling.

  16. Neural Plasticity Associated with Hippocampal PKA-CREB and NMDA Signaling Is Involved in the Antidepressant Effect of Repeated Low Dose of Yueju Pill on Chronic Mouse Model of Learned Helplessness.

    Science.gov (United States)

    Zou, Zhilu; Chen, Yin; Shen, Qinqin; Guo, Xiaoyan; Zhang, Yuxuan; Chen, Gang

    2017-01-01

    Yueju pill is a traditional Chinese medicine formulated to treat syndromes of mood disorders. Here, we investigated the therapeutic effect of repeated low dose of Yueju in the animal model mimicking clinical long-term depression condition and the role of neural plasticity associated with PKA- (protein kinase A-) CREB (cAMP response element binding protein) and NMDA (N-methyl-D-aspartate) signaling. We showed that a single low dose of Yueju demonstrated antidepressant effects in tests of tail suspension, forced swim, and novelty-suppressed feeding. A chronic learned helplessness (LH) protocol resulted in a long-term depressive-like condition. Repeated administration of Yueju following chronic LH remarkably alleviated all of depressive-like symptoms measured, whereas conventional antidepressant fluoxetine only showed a minor improvement. In the hippocampus, Yueju and fluoxetine both normalized brain-derived neurotrophic factor (BDNF) and PKA level. Only Yueju, not fluoxetine, rescued the deficits in CREB signaling. The chronic LH upregulated the expression of NMDA receptor subunits NR1, NR2A, and NR2B, which were all attenuated by Yueju. Furthermore, intracerebraventricular administration of NMDA blunted the antidepressant effect of Yueju. These findings supported the antidepressant efficacy of repeated routine low dose of Yueju in a long-term depression model and the critical role of CREB and NMDA signaling.

  17. Mimicking the effects of spaceflight on bone: Combined effects of disuse and chronic low-dose rate radiation exposure on bone mass in mice

    Science.gov (United States)

    Yu, Kanglun; Doherty, Alison H.; Genik, Paula C.; Gookin, Sara E.; Roteliuk, Danielle M.; Wojda, Samantha J.; Jiang, Zhi-Sheng; McGee-Lawrence, Meghan E.; Weil, Michael M.; Donahue, Seth W.

    2017-11-01

    During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions. This study was designed to investigate the skeletal effects of low-dose rate gamma irradiation (8.5 cGy gamma radiation per day for 20 days, amounting to a total dose of 1.7 Gy) when administered simultaneously to disuse from HLS. The goal was to determine whether continuous, low-dose rate radiation administered during disuse would exacerbate bone loss in a murine HLS model. Four groups of 16 week old female C57BL/6 mice were studied: weight bearing + no radiation (WB+NR), HLS + NR, WB + radiation exposure (WB+RAD), and HLS+RAD. Surprisingly, although HLS led to cortical and trabecular bone loss, concurrent radiation exposure did not exacerbate these effects. Our results raise the possibility that mechanical unloading has larger effects on the bone loss that occurs during spaceflight than low-dose rate radiation.

  18. The synergistic radiosensitizing effect of tirapazamine-conjugated gold nanoparticles on human hepatoma HepG2 cells under X-ray irradiation

    Directory of Open Access Journals (Sweden)

    Liu X

    2016-07-01

    Full Text Available Xi Liu,1–4 Yan Liu,1–4 Pengcheng Zhang,1–4 Xiaodong Jin,1–3 Xiaogang Zheng,1–4 Fei Ye,1–4 Weiqiang Chen,1–3 Qiang Li1–3 1Institute of Modern Physics, 2Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, 3Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou, 4School of Life Science, University of Chinese Academy of Sciences, Beijing, People’s Republic of China Abstract: Reductive drug-functionalized gold nanoparticles (AuNPs have been proposed to enhance the damage of X-rays to cells through improving hydroxyl radical production by secondary electrons. In this work, polyethylene glycol-capped AuNPs were conjugated with tirapazamine (TPZ moiety, and then thioctyl TPZ (TPZs-modified AuNPs (TPZs-AuNPs were synthesized. The TPZs-AuNPs were characterized by transmission electron microscopy, ultraviolet-visible spectra, dynamic light scattering, and inductively coupled plasma mass spectrometry to have a size of 16.6±2.1 nm in diameter and a TPZs/AuNPs ratio of ~700:1. In contrast with PEGylated AuNPs, the as-synthesized TPZs-AuNPs exhibited 20% increment in hydroxyl radical production in water at 2.0 Gy, and 19% increase in sensitizer enhancement ratio at 10% survival fraction for human hepatoma HepG2 cells under X-ray irradiation. The production of reactive oxygen species in HepG2 cells exposed to X-rays in vitro demonstrated a synergistic radiosensitizing effect of AuNPs and TPZ moiety. Thus, the reductive drug-conjugated TPZs-AuNPs as a kind of AuNP radiosensitizer with low gold loading provide a new strategy for enhancing the efficacy of radiation therapy. Keywords: AuNPs, radiation enhancement, synergistic effect, human hepatoma cells, hydroxyl radical production

  19. Low doses effects and gamma radiations low dose rates

    International Nuclear Information System (INIS)

    Averbeck, D.

    1999-01-01

    This expose wishes for bringing some definitions and base facts relative to the problematics of low doses effects and low dose rates effects. It shows some already used methods and some actual experimental approaches by focusing on the effects of ionizing radiations with a low linear energy transfer. (N.C.)

  20. Low dose epidemiology

    International Nuclear Information System (INIS)

    Tirmarche, M.; Hubert, P.

    1992-01-01

    Actually, epidemiological studies have to establish if the assessment of cancer risk can be verified at low chronic radiation doses. The population surveillance must be very long, the side effects and cancers of such radiation appearing much later. In France, this epidemiological study on nuclear workers have been decided recently. Before describing the experiment and french projects in epidemiology of nuclear workers, the authors present the main english and american studies

  1. On the question of radiation exposure of the cervical vertebral column in the palliative X-ray irradiation in case of therapy-resistant scapulohumeral periarthritis with local cervical syndrome and/or cervicobrachial syndrome

    International Nuclear Information System (INIS)

    Hoenle, R.

    1985-01-01

    An improvement is achieved by palliative X-ray irradiation in about 70% out of 47 patients with scapulohumeral periarthritis and local cervival syndrome and/or cervicobrachial syndrome which was hitherto resistant to medicomechanical treatment. Higher rates of success (84%) can be achieved if the patients present an identical symptomatology, but less severe alterations of the vertebral column, even if the vertebral column is not irradiated. In case of severe alterations of the vertebral column, the success of palliative irradiation is diminished, even if the cervical vertebral column is additionally irradiated. (orig.) [de

  2. Question of radiation exposure of the cervical vertebral column in the palliative X-ray irradiation in case of therapy-resistant scapulohumeral periarthritis with local cervical syndrome and/or cervicobrachial syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Hoenle, R

    1985-08-01

    An improvement is achieved by palliative X-ray irradiation in about 70% out of 47 patients with scapulohumeral periarthritis and local cervival syndrome and/or cervicobrachial syndrome which was hitherto resistant to medicomechanical treatment. Higher rates of success (84%) can be achieved if the patients present an identical symptomatology, but less severe alterations of the vertebral column, even if the vertebral column is not irradiated. In case of severe alterations of the vertebral column, the success of palliative irradiation is diminished, even if the cervical vertebral column is additionally irradiated.

  3. Chemoimmunotherapy for relapsed/refractory and progressive 17p13-deleted chronic lymphocytic leukemia (CLL) combining pentostatin, alemtuzumab, and low-dose rituximab is effective and tolerable and limits loss of CD20 expression by circulating CLL cells.

    Science.gov (United States)

    Zent, Clive S; Taylor, Ronald P; Lindorfer, Margaret A; Beum, Paul V; LaPlant, Betsy; Wu, Wenting; Call, Timothy G; Bowen, Deborah A; Conte, Michael J; Frederick, Lori A; Link, Brian K; Blackwell, Sue E; Veeramani, Suresh; Baig, Nisar A; Viswanatha, David S; Weiner, George J; Witzig, Thomas E

    2014-07-01

    Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients with purine analog refractory disease or TP53 dysfunction still have limited treatment options and poor survival. Alemtuzumab-containing chemoimmunotherapy regimens can be effective but frequently cause serious infections. We report a Phase II trial testing the efficacy and tolerability of a short-duration regimen combining pentostatin, alemtuzumab, and low-dose high-frequency rituximab designed to decrease the risk of treatment-associated infections and to limit the loss of CD20 expression by CLL cells. The study enrolled 39 patients with progressive CLL that was either relapsed/refractory (n = 36) or previously untreated with 17p13 deletion (17p13-) (n = 3). Thirteen (33%) patients had both 17p13- and TP53 mutations predicted to be dysfunctional, and eight patients had purine analog refractory CLL without TP53 dysfunction. Twenty-six (67%) patients completed therapy, with only five (13%) patients having treatment-limiting toxicity and no treatment-related deaths. Twenty-two (56%) patients responded to treatment, with 11 (28%) complete responses (four with incomplete bone marrow recovery). Median progression-free survival was 7.2 months, time to next treatment was 9.1 months, and overall survival was 34.1 months. The majority of deaths (82%) were caused by progressive disease, including transformed diffuse large B-cell lymphoma (n = 6). Correlative studies showed that low-dose rituximab activates complement and natural killer cells without a profound and sustained decrease in expression of CD20 by circulating CLL cells. We conclude that pentostatin, alemtuzumab, and low-dose high-frequency rituximab is a tolerable and effective therapy for CLL and that low-dose rituximab therapy can activate innate immune cytotoxic mechanisms without substantially decreasing CD20 expression. © 2014 Wiley Periodicals, Inc.

  4. Inhibition of proliferation and energy metabolism of Cloudman melanoma cells by aphidicolin and X-ray irradiation in vitro. Hemmung der Proliferation und des Energiestoffwechsels von Cloudman-Melanomzellen in vitro durch Aphidicolin und Gammastrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Merte, H [Marburg Univ. (Germany). Abt. fuer Strahlentherapie, Medizinisches Zentrum fuer Radiologie; Schachtschabel, D O [Marburg Univ. (Germany). Inst. fuer Physiologische Chemie; Plamper, G [Marburg Univ. (Germany). Abt. fuer Strahlentherapie, Medizinisches Zentrum fuer Radiologie; Pfab, R [Marburg Univ. (Germany). Abt. fuer Strahlentherapie, Medizinisches Zentrum fuer Radiologie

    1994-06-01

    Purpose: The present investigation is concerned with the effect of aphidicolin (a tetracyclic diterpenoid) and X-ray irradiation - alone or in combination - on cell proliferation, protein production, glucose consumption and lactate production of in vitro cultured Cloudman melanoma cells. Methods: Monolayer cultures of Cloudman melanoma cells in exponential growth phase were irradiated with 2, 4 or 6 Gy (Cobalt-60) or treated for 96 h with 0.1, 0.2 or 1.0 [mu]g/ml aphidicolin. Further, the combination of 0.1 or 0.2 [mu]g/ml aphidicolin with the above mentioned radiation doses were investigated. Measurements were performed in regard to changes of cell number, protein content, glucose consumption and lactate production. Results: Single treatments resulted in a dose-dependent inhibition of cell proliferation, protein production, glucose consumption and lactate production. Combined treatment with aphidicolin and irradiation caused an augmentation of the respective single effects. The inhibitory effects were more pronounced under serum-free than serum-containing culture conditions. Influence of aphidicolin and irradiation did not result in an immediate cell death, but in a state of unbalanced growth with enlarged cells (in part with an increased number of nuclei) and an increased cellular protein content. Conclusions: The combination of aphidicolin with X-ray irradiation caused a stronger effect than the respective single treatments. (orig.)

  5. Damage to the testes of a marine fish, the plaice (Pleuronectes platessa), induced by chronic exposure to low dose rate radiation

    International Nuclear Information System (INIS)

    Knowles, J.F.

    1999-01-01

    Although most authorised disposals of liquid radioactive waste are to the sea, effects of chronic radiation exposure on reproductive endpoints in a marine fish have not so far been investigated. For this reason we have carried out a series of experiments into effects of chronic radiation exposure on plaice, a commercially important marine food species which spends much of its life in contact with sea bed sediments where exposure from radioactive contaminants have been shown to be highest

  6. Low dose X –ray effects on catalase activity in animal tissue

    International Nuclear Information System (INIS)

    Focea, R; Nadejde, C; Creanga, D; Luchian, T

    2012-01-01

    This study was intended to investigate the effect of low-dose X ray-irradiation upon the activity of catalase (CAT) in freshly excised chicken tissues (liver, kidney, brain, muscle). The tissue samples were irradiated with 0.5Gy and 2Gy respectively, in a 6 MV photon beam produced by a clinical linear accelerator (VARIAN CLINAC 2100SC). The dose rate was of 260.88cGy/min. at 100 cm source to sample distance. The catalase level was assayed spectrophotometrically, based on reaction kinetics, using a catalase UV assay kit (SIGMA). Catalase increased activity in various tissue samples exposed to the studied X ray doses (for example with 24 % in the liver cells, p<0.05) suggested the stimulation of the antioxidant enzyme biosynthesis within several hours after exposure at doses of 0.5 Gy and 2 Gy; the putative enzyme inactivation could also occur (due to the injuries on the hydrogen bonds that ensure the specificity of CAT active site) but the resulted balance of the two concurrent processes indicates the cell ability of decomposing the hydrogen peroxide-with benefits for the cell physiology restoration for the chosen low dose radiation.

  7. The effect of well-characterized, very low-dose x-ray radiation on fibroblasts.

    Science.gov (United States)

    Truong, Katelyn; Bradley, Suzanne; Baginski, Bryana; Wilson, Joseph R; Medlin, Donald; Zheng, Leon; Wilson, R Kevin; Rusin, Matthew; Takacs, Endre; Dean, Delphine

    2018-01-01

    The purpose of this study is to determine the effects of low-dose radiation on fibroblast cells irradiated by spectrally and dosimetrically well-characterized soft x-rays. To achieve this, a new cell culture x-ray irradiation system was designed. This system generates characteristic fluorescent x-rays to irradiate the cell culture with x-rays of well-defined energies and doses. 3T3 fibroblast cells were cultured in cups with Mylar® surfaces and were irradiated for one hour with characteristic iron (Fe) K x-ray radiation at a dose rate of approximately 550 μGy/hr. Cell proliferation, total protein analysis, flow cytometry, and cell staining were performed on fibroblast cells to determine the various effects caused by the radiation. Irradiated cells demonstrated increased proliferation and protein production compared to control samples. Flow cytometry revealed that a higher percentage of irradiated cells were in the G0/G1 phase of the cell cycle compared to control counterparts, which is consistent with other low-dose studies. Cell staining results suggest that irradiated cells maintained normal cell functions after radiation exposure, as there were no qualitative differences between the images of the control and irradiated samples. The result of this study suggest that low-dose soft x-ray radiation might cause an initial pause, followed by a significant increase, in proliferation. An initial "pause" in cell proliferation could be a protective mechanism of the cells to minimize DNA damage caused by radiation exposure. The new cell irradiation system developed here allows for unprecedented control over the properties of the x-rays given to the cell cultures. This will allow for further studies on various cell types with known spectral distribution and carefully measured doses of radiation, which may help to elucidate the mechanisms behind varied cell responses to low-dose x-rays reported in the literature.

  8. Chemoimmunotherapy for Relapsed/Refractory and Progressive 17p13 Deleted Chronic Lymphocytic Leukemia (CLL) Combining Pentostatin, Alemtuzumab, and Low Dose Rituximab is Effective and Tolerable and Limits Loss of CD20 Expression by Circulating CLL Cells

    Science.gov (United States)

    Zent, Clive S.; Taylor, Ronald P.; Lindorfer, Margaret A.; Beum, Paul V.; LaPlant, Betsy; Wu, Wenting; Call, Timothy G.; Bowen, Deborah A.; Conte, Michael J.; Frederick, Lori A.; Link, Brian K.; Blackwell, Sue E.; Veeramani, Suresh; Baig, Nisar A.; Viswanatha, David S.; Weiner, George J.; Witzig, Thomas E.

    2014-01-01

    Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients with purine analogue refractory disease or TP53 dysfunction still have limited treatment options and poor survival. Alemtuzumab containing chemoimmunotherapy regimens can be effective but frequently cause serious infections. We report a phase II trial testing the efficacy and tolerability of a short duration regimen combining pentostatin, alemtuzumab, and low dose high frequency rituximab (PAR) designed to decrease the risk of treatment associated infections and limit loss of CD20 expression by CLL cells. The study enrolled 39 patients with progressive CLL that was either relapsed/refractory (n=36) or previously untreated with 17p13 deletion (17p13-)(n=3). Thirteen (33%) patients had both 17p13- and TP53 mutations predicted to be dysfunctional and eight patients had purine analogue refractory CLL without TP53 dysfunction. Twenty-six (67%) patients completed therapy with only five (13%) patients having treatment limiting toxicity, and no treatment related deaths. Twenty-two (56%) patients responded to treatment with 11 (28%) complete responses (four with incomplete bone marrow recovery). Median progression free survival was 7.2 months, time to next treatment 9.1 months, and overall survival 34.1 months. The majority of deaths (82%) were caused by progressive disease including transformed diffuse large B cell lymphoma (n=6). Correlative studies showed that low dose rituximab activates complement and NK cells without a profound and sustained decrease in expression of CD20 by circulating CLL cells. We conclude that PAR is a tolerable and effective therapy for CLL and that low dose rituximab therapy can activate innate immune cytotoxic mechanisms without substantially decreasing CD20 expression. PMID:24723493

  9. Effect of omega 3 fatty acids plus low-dose aspirin on both clinical and biochemical profiles of patients with chronic periodontitis and type 2 diabetes: a randomized double blind placebo-controlled study.

    Science.gov (United States)

    Elwakeel, N M; Hazaa, H H

    2015-12-01

    The aim of this study was, first, to investigate the effect of omega 3 (ω3) fatty acids plus low-dose aspirin with closed debridement in the treatment of patients with periodontitis and type 2 diabetes mellitus (DM), and second, to estimate the expression of monocyte chemoattractant protein-3 (MCP-3) in response to the supposed modulatory therapy. Forty patients with chronic periodontitis and type 2 DM were equally divided into groups 1 (patients received ω3 plus low-dose aspirin for 6 mo) and 2 (patients received placebo during the same period). Evaluation was done clinically (pocket depth, clinical attachment loss, gingival index and plaque index) and biochemically by estimating levels of interleukin 1β and MCP-3 in gingival crevicular fluid, plus investigating the effect of treatment on glycemic control by levels of glycated hemoglobin A1c in serum. All data were collected at baseline, 3 and 6 mo after treatment. Subjects of group 1 showed a highly significant reduction in pocket depth, clinical attachment loss, gingival index (p ≤ 0.01) after 3 and 6 mo compared to group 2. Glycated hemoglobin A1c levels showed a reduction in both groups at the end of the study period, with a non-significant difference (p > 0.05). Furthermore, the treatment protocol showed a significant reduction in levels of MCP-3 and interleukin 1β at 3 and 6 mo compared to the placebo group. Within the limits of the present study, ω3 plus low-dose aspirin proved effective as an adjunct to closed periodontal therapy in the management of patients with periodontitis and type 2 DM. Moreover, MCP-3 was proven to be effective both in the pathogenesis of the disease and as a biomarker in evaluating the response to periodontal treatment. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Phase II study of palliative low-dose local radiotherapy in disseminated indolent non-Hodgkin's lymphoma and chronic lymphocytic leukemia

    DEFF Research Database (Denmark)

    Jóhannsson, Jakob; Specht, Lena; Mejer, Johannes

    2002-01-01

    Indolent non-Hodgkin's lymphoma (INHL) and chronic lymphocytic leukemia (CLL) are highly sensitive to radiotherapy (RT). Previous retrospective studies have shown high response rates after local palliative RT of 4 Gy in 2 fractions, which prompted this prospective Phase II trial of the palliative...

  11. A prospective study of whether radiation pneumonitis is influenced by low-dose irradiated lung volume in primary lung cancer with chronic pulmonary disease

    International Nuclear Information System (INIS)

    Niibe, Yuzuru; Hayakawa, Kazushige; Masuda, Noriyuki; Yoshimura, Hirokuni

    2007-01-01

    The current study prospectively investigated the optimal dose-volume condition in cases of lung cancer with chronic pulmonary disease compared to those without chronic pulmonary disease. Cases of primary lung cancer treated with intended curative radiation therapy were registered in the current study. Their fraction size was limited to 2-3 Gy, so-called standard fractionation. They were prescribed a total dose of 60 Gy for non-small cell lung cancer (NSCLC; n=17) and a total dose of 54 Gy for small cell lung cancer (SCLC; n=4). Of the 21 patients enrolled in this study, 4 had chronic pulmonary disease (study arm), and the others had no chronic pulmonary disease (control arm). Seven received chemotherapy. Symptomatic radiation pneumonitis occurred in 5. Of the four patients in the study arm, two (50%) experienced symptomatic radiation pneumonitis; only 3 of the 17 patients in the control arm (17.6%) experienced symptomatic radiation pneumonitis. Furthermore, the median V 20 of patients who experienced symptomatic radiation pneumonitis in the study arm was 14%, which was higher than that of patients with no symptomatic radiation pneumonitis in the study arm, 5.8%. On the other hand, in the control arm, the median V 20 of patients with symptomatic radiation pneumonitis was 14.2%, about the same as that of patients with no symptomatic radiation pneumonitis in the control arm, 15.1%. The current study suggested that, as much as 15% of V 20 , might play an important role in cases of lung cancer with chronic pulmonary disease. (author)

  12. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates.

    Science.gov (United States)

    Garnier-Laplace, J; Geras'kin, S; Della-Vedova, C; Beaugelin-Seiller, K; Hinton, T G; Real, A; Oudalova, A

    2013-07-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background ~100 nGy/h up to ~10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate-effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution - SSD). We found that the best estimate of the median value (HDR50) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Are radiosensitivity data derived from natural field conditions consistent with data from controlled exposures? A case study of Chernobyl wildlife chronically exposed to low dose rates

    International Nuclear Information System (INIS)

    Garnier-Laplace, J.; Geras’kin, S.; Della-Vedova, C.; Beaugelin-Seiller, K.; Hinton, T.G.; Real, A.; Oudalova, A.

    2013-01-01

    The discrepancy between laboratory or controlled conditions ecotoxicity tests and field data on wildlife chronically exposed to ionising radiation is presented for the first time. We reviewed the available chronic radiotoxicity data acquired in contaminated fields and used a statistical methodology to support the comparison with knowledge on inter-species variation of sensitivity to controlled external γ irradiation. We focus on the Chernobyl Exclusion Zone and effects data on terrestrial wildlife reported in the literature corresponding to chronic dose rate exposure situations (from background∼100 nGy/h up to ∼10 mGy/h). When needed, we reconstructed the dose rate to organisms and obtained consistent unbiased data sets necessary to establish the dose rate–effect relationship for a number of different species and endpoints. Then, we compared the range of variation of radiosensitivity of species from the Chernobyl-Exclusion Zone with the statistical distribution established for terrestrial species chronically exposed to purely gamma external irradiation (or chronic Species radioSensitivity Distribution – SSD). We found that the best estimate of the median value (HDR 50 ) of the distribution established for field conditions at Chernobyl (about 100 μGy/h) was eight times lower than the one from controlled experiments (about 850 μGy/h), suggesting that organisms in their natural environmental were more sensitive to radiation. This first comparison highlights the lack of mechanistic understanding and the potential confusion coming from sampling strategies in the field. To confirm the apparent higher sensitive of wildlife in the Chernobyl Exclusion Zone, we call for more a robust strategy in field, with adequate design to deal with confounding factors. -- Highlights: ► Discrepancy between controlled tests and Chernobyl effects data on wildlife was examined. ► We proposed a method to correct the dosimetry used for Chernobyl wildlife. ► Wildlife from the

  14. Effect of treatment with cyclophosphamide in low doses upon the onset of delayed type hypersensitivity in mice chronically infected with Trypanosoma cruzi: involvement of heart interstitial dendritic cells

    Directory of Open Access Journals (Sweden)

    Torriceli Souza The

    2013-09-01

    Full Text Available Acute infection with Trypanosoma cruzi results in intense myocarditis, which progresses to a chronic, asymptomatic indeterminate form. The evolution toward this chronic cardiac form occurs in approximately 30% of all cases of T. cruzi infection. Suppression of delayed type hypersensitivity (DTH has been proposed as a potential explanation of the indeterminate form. We investigated the effect of cyclophosphamide (CYCL treatment on the regulatory mechanism of DTH and the participation of heart interstitial dendritic cells (IDCs in this process using BALB/c mice chronically infected with T. cruzi. One group was treated with CYCL (20 mg/kg body weight for one month. A DTH skin test was performed by intradermal injection of T. cruzi antigen (3 mg/mL in the hind-footpad and measured the skin thickness after 24 h, 48 h and 72 h. The skin test revealed increased thickness in antigen-injected footpads, which was more evident in the mice treated with CYCL than in those mice that did not receive treatment. The thickened regions were characterised by perivascular infiltrates and areas of necrosis. Intense lesions of the myocardium were present in three/16 cases and included large areas of necrosis. Morphometric evaluation of lymphocytes showed a predominance of TCD8 cells. Heart IDCs were immunolabelled with specific antibodies (CD11b and CD11c and T. cruzi antigens were detected using a specific anti-T. cruzi antibody. Identification of T. cruzi antigens, sequestered in these cells using specific anti-T. cruzi antibodies was done, showing a significant increase in the number of these cells in treated mice. These results indicate that IDCs participate in the regulatory mechanisms of DTH response to T. cruzi infection.

  15. Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation.

    Science.gov (United States)

    Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

    2015-02-01

    Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  16. New radiobiological findings bearing on the 1977 ICRP recommendations. [Sensitivity of mouse and monkey prenatal oocytes to chronic, low-dose, tritium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, R.L.

    1979-02-14

    Recent experiments on low-level irradiation during development raise questions relevant to ICRP Publication 26. Mice and monkeys were studied; the measured endpoint was the radiation-induced loss of female germ cells. Three issues are examined. The first is the numerical value of Q (quality factor) appropriate for low-energy beta rays. Comparisons of tritium with gamma radiation were made under conditions of chronic, low-level exposure, and the relative biological effectiveness (RBE) was found to approach 3. Its bearing on ICRP's recommendations concerning Q applicable to tritium is discussed. Second, female germ cells in squirrel monkeys before birth were discovered to be extraordinarily radiosensitive, more easily destroyed than those of mice. If this holds for other primates too, it has radiation-protection implications hitherto overlooked. Third, the contrast between massive germ-cell loss from chronic exposure in prenatal squirrel monkeys and reported radioresistance of oocytes to acute exposure in rhesus monkeys, unless due to species difference, suggests that during development protracted irradiation may be especially injurious. This also could have important radiation-protection implications and is under investigation. (ERB)

  17. Radioprotective Effect of Alk(enyl Thiosulfates Derived from Allium Vegetables against DNA Damage Caused by X-Ray Irradiation in Cultured Cells: Antiradiation Potential of Onions and Garlic

    Directory of Open Access Journals (Sweden)

    Hye-Sook Chang

    2012-01-01

    Full Text Available To evaluate a radioprotective effect of sodium n-propyl thiosulfate (NPTS and sodium 2-propenyl thiosulfate (2PTS derived from onions and garlic, respectively, rat hepatoma H4IIE cells and mouse lymphoma L5178Y cells were preincubated with each of these compounds for 48 hours at 37°C before receiving 10 Gy of X-ray irradiation. Cell damage caused by the irradiation was quantified as comet tail moment, which represents the degree of DNA damage. X-ray-induced DNA damage was significantly decreased in both H4IIE and L5178Y cells by micromolar concentrations of NPTS and 2PTS compared with the control without the compounds. The protective effect was more potent with 2PTS than NPTS. Onions and garlic have antiradiation potential.

  18. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    International Nuclear Information System (INIS)

    May, J.C.; Rey, L.; Lee, C.-J.; Arciniega, Juan

    2004-01-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine

  19. Evaluation of components of X-ray irradiated 7-valent pneumococcal conjugate vaccine and pneumococcal vaccine polyvalent and X-ray and gamma-ray irradiated acellular pertussis component of DTaP vaccine products

    Energy Technology Data Exchange (ETDEWEB)

    May, J.C. E-mail: may@cber.fda.gov; Rey, L. E-mail: louis.rey@bluewin.ch; Lee, C.-J.; Arciniega, Juan

    2004-10-01

    Samples of pneumococcal vaccine polyvalent, 7-valent pneumococcal conjugate vaccine, and two different diphtheria and tetanus toxoids and acellular pertussis vaccines adsorbed were irradiated with X-rays and/or gamma-rays (Co-60). Mouse IgG and IgM antibody responses (ELISA) for types 9V, 14, 18C, and 19F pneumococcal polysaccharides and conjugates indicated that the polysaccharides were more tolerant of the radiation than the conjugates. The mouse antibody response for the detoxified pertussis toxin (PT) antigen, filamentous hemagglutinin antigen (FHA), pertactin (PRN), and fimbriae types 2 and 3 (FIM) antigens for the appropriate vaccine type indicated that the antibody response was not significantly changed in the 25 kGy X-ray irradiated vaccines frozen in liquid nitrogen compared to the control vaccine.

  20. Low dose irradiation reduces cancer mortality rates

    International Nuclear Information System (INIS)

    Luckey, T.D.

    2000-01-01

    . Increased production of many molecules (interleukins, interferons, leukotrienes, chemotactic agents, and mitogens) related to immunity are found in mice exposed to low dose irradiation (Lim, S.-Z., Biologic Effects of Low Level Exposures to Radiation and Related Agents, pp.15-16, 1993). Those plus many enzymes and cofactors are inter- and intra-cellular agents involved in gene expression, T-cell maturation, phagocytosis, signal transduction, antigen reception and antibody production. This basic science information has been utilized for cancer therapy in Japanese and United States clinics. With the usual radio-, chemo- and surgical therapy, the 10 year survival of non-Hodgkin's lymphoma was 59%; when this was augmented by low dose irradiation, survival was 80% (Sakamoto, K., ICONE-7 Abstracts, p 50-51, 1999). Low dose irradiation of the mid-section of the body was effective. This area includes many elements of the immune system: the spleen with its germinal centers and lymphoid follicles, the liver with its phagocytosing Kupffer cells, kidney phagocytes, and the lamina propria and Peyer's patches of the intestinal wall. Irradiation of either the head and chest or the groin-legs area was unresponsive. Chronic low dose irradiation redness premature cancer mortality 51%. Standards should be revised with health, not risks, as the goal. Safe supplementation with ionizing radiation would provide a new plateau of health for people and wealth for nations. (author)

  1. Effects of chronic low-dose radiation exposure and non-radiation factors on eye pathology in the Techa River Cohort

    International Nuclear Information System (INIS)

    Mikryukova, L.D.; Akleyev, A.V.

    2008-01-01

    Full text: As a result of the Mayak PA activities, radioactive wastes were discharged into the Techa River over the period 1949-1956. Data on eye pathology among Techa riverside residents chronically exposed to radiation (external and internal) have been collected and analyzed. The cohort which includes persons of the two genders born before 1950 gives one of the rare opportunities to assess the risk of late effects on human health associated with small-dose radiation exposure. Currently, the cohort numbers 29,749 individuals. In terms of ethnicity, 80 % of the cohort members are Slavs, and 20 % are Tartars and Bashkirs. The first study and analyses of eye pathology were conducted for this cohort during the period from 2001 through 2004. It was established that the cumulative rate of eye disease incidence increased with age and exposure dose. The relative risk value for development of ophthalmopathy among members of the study group was estimated taking into account the potential effects of gender, ethnicity and attained age. The relative risk value was 2.42 per 1 Gy of absorbed dose to soft tissues (95 % CI: 1.94; 3.03). With increase in attained age by 10 years an 8 % increase in the incidence of eye pathology was registered (p<0.001). The rate of eye disease incidence estimated for women was significantly higher than that for men (p<0.05 %). No significant differences were noted in the coefficient of eye disease incidence calculated for different ethnic groups. The structure of ophthalmopathy registered in residents of the Techa riverside villages chronically exposed in the dose range from 0 to 1,180 mGy is characterized by prevalence of cataracts, retinal and chorioid disorders. The rates of eye disease incidence were found to be dependent on external exposure dose; the highest doses were observed in the dose groups with doses 25 mGy. A statistically significant increase in the incidence of retinal angiosklerosis and a manifest tendency to develop cataracts was

  2. X-ray irradiation and Rho-kinase inhibitor additively induce invasiveness of the cells of the pancreatic cancer line, MIAPaCa-2, which exhibits mesenchymal and amoeboid motility

    International Nuclear Information System (INIS)

    Fujita, Mayumi; Otsuka, Yoshimi; Yamada, Shigeru; Iwakawa, Mayumi; Imai, Takashi

    2011-01-01

    Tumor cells can migrate and invade tissue by two modes of motility: mesenchymal and amoeboid. X-ray or γ-ray irradiation increases the invasiveness of tumor cells with mesenchymal motility through the induction of matrix metalloproteinases (MMP), and this increase is suppressed by MMP inhibitors (MMPI). However, the effects of X-ray or γ-ray irradiation on the invasiveness of tumor cells with amoeboid motility remain unclear. We investigated the effect of irradiation on amoeboid motility by using cells of the human pancreatic cancer line, MIAPaCa-2, which exhibits both modes of motility. The X-ray-induced invasiveness of MIAPaCa-2 cells was associated with the upregulation of MMP2 at both the RNA and protein levels and was inhibited by MMPI treatment. Amoeboid-mesenchymal transition was slightly induced after irradiation. The MMPI treatment caused mesenchymal-amoeboid transition without significant increase in invasiveness, while the ROCK inhibitor (ROCKI) stimulated amoeboid-mesenchymal transition and enhanced invasiveness under both non-irradiated and irradiated conditions. This ROCKI-induced transition was accompanied by the upregulation of MMP2 mRNA and protein. Exposure to both irradiation and ROCKI further enhanced MMP2 expression and had an additive effect on the invasiveness of MIAPaCa-2 cells. Additionally, exposure to MMPI led to significant suppression of both radiation-induced and the basal invasiveness of MIAPaCa-2 cells. This suggests that ROCKI treatment, especially with concomitant X-ray irradiation, can induce invasion of cancer cells and should be used only for certain types of cancer cells. Simultaneous use of inhibitors, ROCKI and MMPI may be effective in suppressing invasiveness under both X-ray-irradiated and non-irradiated conditions. (author)

  3. Impulsiveness, overactivity, and poorer sustained attention improve by chronic treatment with low doses of l-amphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD).

    Science.gov (United States)

    Sagvolden, Terje

    2011-03-30

    ADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Overactivity, impulsiveness, and inattentiveness are presently regarded as the main clinical symptoms. There is no biological marker, but there is considerable evidence to suggest that ADHD behavior is associated with poor dopaminergic and noradrenergic modulation of neuronal circuits that involve the frontal lobes. The best validated animal model of ADHD, the Spontaneously Hypertensive Rat (SHR), shows pronounced overactivity, impulsiveness, and deficient sustained attention. The primary objective of the present research was to investigate behavioral effects of a range of doses of chronic l-amphetamine on ADHD-like symptoms in the SHR. The present study tested the behavioral effects of 0.75 and 2.2 mg l-amphetamine base/kg i.p. in male SHRs and their controls, the Wistar Kyoto rat (WKY). ADHD-like behavior was tested with a visual discrimination task measuring overactivity, impulsiveness and inattentiveness. The striking impulsiveness, overactivity, and poorer sustained attention seen during baseline conditions in the SHR were improved by chronic treatment with l-amphetamine. The dose-response curves were, however, different for the different behaviors. Most significantly, the 0.75 mg/kg dose of l-amphetamine improved sustained attention without reducing overactivity and impulsiveness. The 2.2 mg/kg dose improved sustained attention as well as reduced SHR overactivity and impulsiveness. The effects of l-amphetamine to reduce the behavioral symptoms of ADHD in the SHR were maintained over the 14 days of daily dosing with no evidence of tolerance developing.

  4. A Randomised, Controlled Comparison of Low-Dose Polyethylene Glycol 3350 plus Electrolytes with Ispaghula Husk in the Treatment of Adults with Chronic Functional Constipation.

    Science.gov (United States)

    Wang, Hui-Ji; Liang, Xiao-Mei; Yu, Zhong-Lin; Zhou, Li-Ya; Lin, San-Ren; Geraint, Mike

    2004-01-01

    To compare the efficacy and safety of polyethylene glycol (PEG) 3350 plus electrolytes (PEG+E; Movicol((R))) with that of ispaghula husk (psyllium; Konsyl((R))) in the treatment of constipation. Male or female adults with chronic functional constipation. This was a randomised, controlled, open-label, parallel-group trial. Study treatment was either PEG+E 13.8g/sachet dissolved in water twice daily or ispaghula husk 3.5g/sachet dissolved in water twice daily for a period of 2 weeks. Assessments were at baseline and after 1 and 2 weeks' therapy and by patient daily diary card. The primary outcome measures were weekly defaecation rate, stool consistency according to the Bristol Stool Form scale, time to first defaecation, and overall efficacy, which combined defaecation rate, stool consistency and difficulty on defaecation. Adverse effects were recorded and laboratory assessments were performed before and at the end of the treatment period. Sixty-three patients were randomised to each treatment group. Treatment was highly effective in 50/63 patients in the PEG+E group compared with 26/63 in the ispaghula husk group, and the overall efficacy rates were 92% and 73%, respectively (p = 0.005). PEG+E increased the mean weekly defaecation rate from 1.18 (SD 0.77) at baseline to 7.95 (SD 3.49) after 1 week and 8.48 (SD 3.55) after 2 weeks. In the ispaghula husk group the mean weekly defaecation rate increased from 1.33 (SD 0.68) at baseline to 5.33 (SD 2.81) after 1 week and to 5.71 (SD 2.49) after 2 weeks. The treatment differences for defaecation rates were all statistically significant (p PEG+E or ispaghula husk normalised stools in 55/63 (87.3%) and 42/63 (66.7%) of patients (p PEG 3350 plus electrolytes is more effective and more rapid in its onset of action than ispaghula husk, and is equally well tolerated.

  5. Activation of chemical biological defense mechanisms and remission of vital oxidative injury by low dose radiation

    International Nuclear Information System (INIS)

    Yamaoka, K.; Nomura, T.; Kojima, S.

    2000-01-01

    the effect of low-dose X-ray irradiation on the synthesis of glutathione peroxidase (GSHP x ), which is an antioxidant that catalyzes this reaction. The results suggest that H 2 O 2 produced by increased SOD activity can be detoxicated into H 2 O and O 2 due to simultaneous enhancement of the GSHP x activity by X-ray irradiation at 20 cGy, in contrast to irradiation at 400 cGy. The results also show the enhancement in enzyme activities by induction of their synthesis shortly after irradiation at 20 cGy. Moreover, as this phenomenon was observed in BALB/c mice (which are more radiation sensitive compared to other mouse strains) and radiation-resistant C57BL/6NJcl mice, it was considered to be a common phenomenon in the rat spleen. Remission of vital oxidative injury by low dose radiation: (1) We studied the effects of a single post whole-body low-dose radiation (50 cGy of γ-ray) on mice with ferric nitrilotriacetate (Fe 3+ - NTA)-induced transient hepatopathy. As a result, low-dose radiation accelerated the rate of recovery. Based on the changes in glutamic oxaloacetic transaminase activities, glutamic pyruvic transaminase activities and liquid peroxide levels, it was shown that hepatopathy improved by low dose radiation 3 hours after Fe 3+ - NTA administration. This may be because of the enhancement of antioxidant agents such as total glutathione (GSH+GSSG), glutathione peroxidase, glutathione reductase and γ-glutamylcysteine synthetase by low-dose radiation. These findings suggest that low-dose radiation relieved functional disorder at least in the livers of mice with active oxygen species related diseases. (2) Indications for treatment at the Misasa Hot Spring, a radon producing radioactive spring, include hypertension, diabetes mellitus and pain. To clarify its mechanisms of action on these conditions, we evaluated dynamic changes in blood components such as vasoactive substances after radon inhalation. Vasodilation, alleviation of diabetic symptoms and morphine

  6. A pragmatic, phase III, multisite, double-blind, placebo-controlled, parallel-arm, dose increment randomised trial of regular, low-dose extended-release morphine for chronic breathlessness: Breathlessness, Exertion And Morphine Sulfate (BEAMS) study protocol.

    Science.gov (United States)

    Currow, David; Watts, Gareth John; Johnson, Miriam; McDonald, Christine F; Miners, John O; Somogyi, Andrew A; Denehy, Linda; McCaffrey, Nicola; Eckert, Danny J; McCloud, Philip; Louw, Sandra; Lam, Lawrence; Greene, Aine; Fazekas, Belinda; Clark, Katherine C; Fong, Kwun; Agar, Meera R; Joshi, Rohit; Kilbreath, Sharon; Ferreira, Diana; Ekström, Magnus

    2017-07-17

    Chronic breathlessness is highly prevalent and distressing to patients and families. No medication is registered for its symptomatic reduction. The strongest evidence is for regular, low-dose, extended- release (ER) oral morphine. A recent large phase III study suggests the subgroup most likely to benefit have chronic obstructive pulmonary disease (COPD) and modified Medical Research Council breathlessness scores of 3 or 4. This protocol is for an adequately powered, parallel-arm, placebo-controlled, multisite, factorial, block-randomised study evaluating regular ER morphine for chronic breathlessness in people with COPD. The primary question is what effect regular ER morphine has on worst breathlessness, measured daily on a 0-10 numerical rating scale. Uniquely, the coprimary outcome will use a FitBit to measure habitual physical activity. Secondary questions include safety and, whether upward titration after initial benefit delivers greater net symptom reduction. Substudies include longitudinal driving simulation, sleep, caregiver, health economic and pharmacogenetic studies. Seventeen centres will recruit 171 participants from respiratory and palliative care. The study has five phases including three randomisation phases to increasing doses of ER morphine. All participants will receive placebo or active laxatives as appropriate. Appropriate statistical analysis of primary and secondary outcomes will be used. Ethics approval has been obtained. Results of the study will be submitted for publication in peer-reviewed journals, findings presented at relevant conferences and potentially used to inform registration of ER morphine for chronic breathlessness. NCT02720822; Pre-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  7. Analysis of the Effect of Chronic and Low-Dose Radiation Exposure on Spermatogenic Cells of Male Large Japanese Field Mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant Accident.

    Science.gov (United States)

    Takino, Sachio; Yamashiro, Hideaki; Sugano, Yukou; Fujishima, Yohei; Nakata, Akifumi; Kasai, Kosuke; Hayashi, Gohei; Urushihara, Yusuke; Suzuki, Masatoshi; Shinoda, Hisashi; Miura, Tomisato; Fukumoto, Manabu

    2017-02-01

    In this study we analyzed the effect of chronic and low-dose-rate (LDR) radiation on spermatogenic cells of large Japanese field mice ( Apodemus speciosus ) after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident. In March 2014, large Japanese field mice were collected from two sites located in, and one site adjacent to, the FNPP ex-evacuation zone: Tanashio, Murohara and Akogi, respectively. Testes from these animals were analyzed histologically. External dose rate from radiocesium (combined 134 Cs and 137 Cs) in these animals at the sampling sites exhibited 21 μGy/day in Tanashio, 304-365 μGy/day in Murohara and 407-447 μGy/day in Akogi. In the Akogi group, the numbers of spermatogenic cells and proliferating cell nuclear antigen (PCNA)-positive cells per seminiferous tubule were significantly higher compared to the Tanashio and Murohara groups, respectively. TUNEL-positive apoptotic cells tended to be detected at a lower level in the Murohara and Akogi groups compared to the Tanashio group. These results suggest that enhanced spermatogenesis occurred in large Japanese field mice living in and around the FNPP ex-evacuation zone. It remains to be elucidated whether this phenomenon, attributed to chronic exposure to LDR radiation, will benefit or adversely affect large Japanese field mice.

  8. Statistical and low dose response

    International Nuclear Information System (INIS)

    Thorson, M.R.; Endres, G.W.R.

    1981-01-01

    The low dose response and the lower limit of detection of the Hanford dosimeter depend upon may factors, including the energy of the radiation, whether the exposure is to be a single radiation or mixed fields, annealing cycles, environmental factors, and how well various batches of TLD materials are matched in the system. A careful statistical study and sensitivity analysis were performed to determine how these factors influence the response of the dosimeter system. Estimates have been included in this study of the standard deviation of calculated dose for various mixed field exposures from 0 to 1000 mrem

  9. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    International Nuclear Information System (INIS)

    Korzeneva, Inna B.; Kostuyk, Svetlana V.; Ershova, Elizaveta S.; Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V.; Porokhovnik, Lev N.; Veiko, Natalia N.

    2016-01-01

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  10. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Ershova, Elizaveta S. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation); Skorodumova, Elena N.; Zhuravleva, Veronika F.; Pankratova, Galina V.; Volkova, Irina V.; Stepanova, Elena V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190 Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Veiko, Natalia N. [Research Centre for Medical Genetics, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); V. A. Negovsky Research Institute of General Reanimatology, Moscow, 107031 (Russian Federation)

    2016-09-15

    Highlights: • A transcribed region of human ribosomal repeat is resistant to double-strand breaks in the environment of a raised endonuclease activity. • Hybridization-based techniques are preferable for the analysis of damaged and/or oxidized genomic fragments, rather than the qRT-PCR method. • A chronic exposure to the low-dose IR induces an elevation of the rDNA content in the human circulating cfDNA as compared to cellular DNA. • An exposure to IR entails a decrease of the level of the human circulating satellite III (1q12) as compared to cellular DNA (RsatIII index). • The RrDNA/RsatIII ratio is a potential marker of a chronic IR individual exposure. - Abstract: A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N = 88) and tritium β-radiation (N = 88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the

  11. Influence of serum extraction from the culture medium and of sublethal X-ray irradiation upon microvilli and invaginations of the membrane of Ehrlich ascites tumor cells in monolayer culture

    International Nuclear Information System (INIS)

    Laudenbach, G.; Pfab, R.; Hess, F.; Schachtschabel, D.O.

    1984-01-01

    In order to find out modifications of microvilli and invaginations, the cellular surfaces of Ehrlich ascites tumor cells in monolayer culture (basal medium of Eagle + 10% fetal calf serum) were investigated with the aid of electron-microscopic cross-sections. The tumor cells had been cultured without serum 24 hours prior to investigation or irradiated with 2 Gy. Morphometric evaluation after cell culture in a serum-free medium showed a reduced number of microvilli and a diminution of sections of microvilli. As already described before, a reduction of cell proliferation, of the microtubule-microfilament system, and of the endocytosis activity occurs under these serum-free conditions. The number of invaginations (related to a constant membrane part) was reduced by nearly 50% after serum extraction. Similarly to serum extraction, sublethal X-ray irradiation reduced the sections of microvilli, whereas the number of microvilli increased slightly. Contrary to the effect of serum extraction, the irradiated cells showed twice as many invaginations as the non-irradiated control cells. These differences in the surface structures are interpreted as a result of modified growth stimulations (+- serum) and radiogenic reparation processes. (orig.) [de

  12. Human circulating ribosomal DNA content significantly increases while circulating satellite III (1q12) content decreases under chronic occupational exposure to low-dose gamma- neutron and tritium beta-radiation.

    Science.gov (United States)

    Korzeneva, Inna B; Kostuyk, Svetlana V; Ershova, Elizaveta S; Skorodumova, Elena N; Zhuravleva, Veronika F; Pankratova, Galina V; Volkova, Irina V; Stepanova, Elena V; Porokhovnik, Lev N; Veiko, Natalia N

    A single exposure to ionizing radiation (IR) results in an elevated cell-free DNA (cfDNA) content in the blood plasma. In this case, the cfDNA concentration can be a marker of the cell death in the organism. However, a chronic exposure to a low-dose IR enhances both the endonuclease activity and titer of antibodies to DNA in blood plasma, resulting in a decrease of the total concentration of circulating cfDNA in exposed people. In this case, the total cfDNA concentration should not be considered as a marker of the cell death in an exposed body. We assumed that a pool of the cfDNA circulating in the exposed people contains DNA fragments, which are resistant to a double-strand break formation in the environment of the elevated plasma endonuclease activity, and can be accumulated in the blood plasma. In order to test this hypothesis, we studied the content of GC-rich sequences (69%GC) of the transcribed region of human ribosomal repeat (rDNA), as well as the content of AT-rich repeat (63%AT) of satellite III (1q12) in the cfDNA samples obtained from 285 individuals. We have found that a chronic exposure to gamma-neutron radiation (N=88) and tritium β-radiation (N=88) evokes an increase of the rDNA content (RrDNA index) and a decrease of the satellite III content (RsatIII index) in the circulating cfDNA as compared with the cfDNA of non-exposed people (N=109). Such index that simultaneously displays both the increase of rDNA content and decrease of satellite III content in the cfDNA (RrDNA/RsatIII) can be recommended as a marker of chronic processes in the body that involve the elevated cell death rate and/or increased blood plasma endonuclease activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Low Dose Risk, Decisions, and Risk Communication

    International Nuclear Information System (INIS)

    Flynn, James

    2002-01-01

    The overall research objective was to establish new levels of information about how people, groups, and communities respond to low dose radiation exposure. This is basic research into the social psychology of individual, group, and community responses to radiation exposures. The results of this research are directed to improving risk communication and public participation in management of environmental problems resulting from low dose radiation

  14. Low dose irradiation and biological defense mechanisms

    International Nuclear Information System (INIS)

    Sugahara, Tsutomu; Sagan, L.A.; Aoyama, Takashi

    1992-01-01

    It has been generally accepted in the context of radiation protection that ionizing radiation has some adverse effect even at low doses. However, epidemiological studies of human populations cannot definitively show its existence or absence. Furthermore, recent studies of populations living in areas of different background radiation levels reported some decrease in adverse health effects at high background levels. Genetic studies of atomic bomb survivors failed to produce statistically significant findings on the mutagenic effects of ionizing radiation. A British study however, suggests that a father's exposure to low dose radiation on the job may increase his children's risk of leukemia. On the other hand, many experimental studies have raised the possibility that low doses of ionizing radiation may not be harmful or may even produce stimulating or adaptive responses. The term 'hormesis' has come to be used to describe these phenomena produced by low doses of ionizing radiation when they were beneficial for the organisms studied. At the end of the International Conference on Low Dose Irradiation one conclusion appeared to be justified: radiation produces an adaptive response, though it is not universally detected yet. The conference failed to obtain any consensus on risk assessment at low doses, but raised many problems to be dealt with by future studies. The editors therefore believe that the Proceedings will be useful for all scientists and people concerned with radiation protection and the biological effects of low-dose irradiation

  15. GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, F.; Molina, M.; Berthier-Vergnes, O.; Lamartine, J. [Universite de Lyon, Lyon, F-69003 (France); Universite Lyon 1, Lyon, F-69003 (France); CNRS, UMR5534, Centre de Genetique Moleculaire et Cellulaire, Villeurbanne, F-69622 (France); Malet, C.; Ginestet, C. [Centre Leon Berard, Service de Radiotherapie, Lyon F-69008 (France); Martin, M.T. [Laboratoire de Genomique et Radiobiologie de la Keratinopoiese, CEA, IRCM, Evry F-91000 (France)

    2009-07-01

    Background: The general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown. Results: The present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knockdown was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide micro-arrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGF{beta} signalling and stress response. Conclusion: Taken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation. (authors)

  16. GATA3 is a master regulator of the transcriptional response to low-dose ionizing radiation in human keratinocytes

    International Nuclear Information System (INIS)

    Bonin, F.; Molina, M.; Berthier-Vergnes, O.; Lamartine, J.; Malet, C.; Ginestet, C.; Martin, M.T.

    2009-01-01

    Background: The general population is constantly exposed to low levels of radiation through natural, occupational or medical irradiation. Even if the biological effects of low-level radiation have been intensely debated and investigated, the molecular mechanisms underlying the cellular response to low doses remain largely unknown. Results: The present study investigated the role of GATA3 protein in the control of the cellular and molecular response of human keratinocytes exposed to a 1 cGy dose of X-rays. Chromatin immunoprecipitation showed GATA3 to be able to bind the promoter of 4 genes responding to a 1 cGy exposure. To go further into the role of GATA3 after ionizing radiation exposure, we studied the cellular and molecular consequences of radiation in GATA3 knock-down cells. Knockdown was obtained by lentiviral-mediated expression of an shRNA targeting the GATA3 transcript in differentiated keratinocytes. First, radiosensitivity was assessed: the toxicity, in terms of immediate survival (with XTT test), associated with 1 cGy radiation was found to be increased in GATA3 knock-down cells. The impact of GATA3 knock-down on the transcriptome of X-ray irradiated cells was also investigated, using oligonucleotide micro-arrays to assess changes between 3 h and 72 h post-irradiation in normal vs GATA3 knock-down backgrounds; transcriptome response was found to be completely altered in GATA3 knock-down cells, with a strong induction/repression peak 48 h after irradiation. Functional annotation revealed enrichment in genes known to be involved in chaperone activity, TGFβ signalling and stress response. Conclusion: Taken together, these data indicate that GATA3 is an important regulator of the cellular and molecular response of epidermal cells to very low doses of radiation. (authors)

  17. Effects of low dose radiation on tumor growth and changes of erythrocyte immune function and activity of SOD in tumor-bearing mice

    International Nuclear Information System (INIS)

    Yu Hongsheng; Lu Yanda

    2001-01-01

    Objective: To study the effect of low dose radiation on tumor growth and changes of erythrocyte immune function and activity of SOD in the tumor-bearing mice. Methods: Kunming strain male mice were implanted with S 180 sarcoma cells in the right inguen subcutaneously as an experimental in situ animal model. Six hours before implantation the mice were given 75 mG whole-body X-ray irradiation and tumor-formation rate was counted 5 days late. From then, every two days the tumor volume was measured to draw a tumor growth curve. Fifteen days later, all mice were killed to measure the tumor weight, observe the necrosis area and the tumor-infiltration lymphoreticular cells (TIL) in the tumor pathologically. At the same time, erythrocyte immune function and activity of SOD were tested. Results: (1) The mice pre-exposed to low dose radiation had a lower tumor formation rate than those without a pre-exposed (P < 0.05). (2) The tumor growth slowed down significantly in mice receiving a low does irradiation; The average tumor weight in mice receiving a low dose irradiation was lighter too (P < 0.05). (3) The tumor necrosis areas were larger and TILs were more in the irradiation group than those of the control group. (4) The erythrocyte immune function and activity of SOD in the irradiation group were all higher significantly than those of the control group ( P < 0.05). Conclusion: Low dose radiation could markedly increase anti-tumor ability of the organism and improve the erythrocyte immune function and activity of SOD in red cells, suggesting it could be useful in clinical cancer treatment

  18. Low-dose ionizing irradiation triggers a 53BP1 response to DNA double strand breaks in mouse spermatogonial stem cells.

    Science.gov (United States)

    Le, Wei; Qi, Lixin; Li, Jiaxuan; Wu, DengIong; Xu, Jun; Zhang, Jinfu

    2016-01-01

    The present study aims to examine the effect of low-dose ionizing irradiation on DNA double strand breaks (DSB) in mouse spermatogonial stem cells (SSCs) and reveal the underlying pathways for the DNA repair for DSB in SSCs. Eighteen one-month-old mice were divided into 6 groups and sacrificed separately at 45 minutes, 2 hours, 24 hours, 48 hours, and 72 hours after 0.1Gy X-ray irradiation (mice without receiving ionizing irradiation served as control). After perfusion fixation, testes were removed, sectioned, and followed by staining of γH2AX, 53BP1, Caspase 3, and promyelocytic leukemia zinc-finger (PLZF) for analysis among the different groups. The staining was observed by immunofluorescence visualized by confocal laser scanning. After low-dose irradiation, only 53BP1, but not Caspase3 or γH2AX was upregulated in PLZF positive SSCs within 45 minutes. The expression level of 53BP1 gradually decreased 24 hours after irradiation. Moreover, low-dose irradiation had no effect on the cell number and apoptotic status of SSCs. However other spermatogenic cells highly expressed γH2AX shortly after irradiation which was dramatically reduced following the events of DNA repair. It appears that low-dose ionizing irradiation may cause the DNA DSB of mouse spermatogenic cells. 53BP1, but not γH2AX, is involved in the DNA repair for DSB in SSCs. Our data indicates that 53BP1 plays an important role in the pathophysiological repair of DNA DSB in SSCs. This may open a new avenue to understanding the mechanisms of DNA repair of SSCs and male infertility.

  19. Chronic treatment of (R)-α-lipoic acid reduces blood glucose and lipid levels in high-fat diet and low-dose streptozotocin-induced metabolic syndrome and type 2 diabetes in Sprague-Dawley rats.

    Science.gov (United States)

    Ghelani, Hardik; Razmovski-Naumovski, Valentina; Nammi, Srinivas

    2017-06-01

    (R)- α -lipoic acid ( ALA ), an essential cofactor in mitochondrial respiration and a potential antioxidant, possesses a wide array of metabolic benefits including anti-obesity, glucose lowering, insulin-sensitizing, and lipid-lowering effects. In this study, the curative effects of ALA (100 mg/kg) on a spectrum of conditions related to metabolic syndrome and type 2 diabetes ( T2D ) were investigated in a high-fat diet (HFD)-fed and low-dose streptozotocin (STZ)-induced rat model of metabolic syndrome and T2D . The marked rise in the levels of glucose, triglycerides, total-cholesterol, LDL-cholesterol, and VLDL-cholesterol in the blood of HFD-fed and low-dose STZ-injected rats were significantly reduced by ALA treatment. Furthermore, ALA treatment significantly increased the serum HDL-cholesterol levels and tended to inhibit diabetes-induced weight reduction. Mathematical computational analysis revealed that ALA also significantly improved insulin sensitivity and reduced the risk of atherosclerotic lesions and coronary atherogenesis. This study provides scientific evidence to substantiate the use of ALA to mitigate the glucose and lipid abnormality in metabolic syndrome and T2D .

  20. Reduced oxygen enhancement ratio at low doses

    International Nuclear Information System (INIS)

    Palcic, B.; Skarsgard, L.D.

    1984-01-01

    The oxygen depletion rate in cell suspensions was measured using a Clark electrode. It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below 0.1μm, the levels which could give any significant enhancement to radiation inactivation by x-rays. The measured O/sub 2/ depletion rates were comparable to those reported in the literature. Chinese hamster cells (CHO) were made hypoxic by gas exchange, combined with metabolic consumption of oxygen by cells at 37 0 C. Full survival curves were determined in the dose range 0 to 3Gy using the low dose survival assay. The results confirmed the authors' earlier finding that the OER decreases at low doses. The authors therefore believe that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay

  1. LOW DOSE RISK, DECISIONS, and RISK COMMUNICATION

    International Nuclear Information System (INIS)

    Flynn, James

    2002-01-01

    The objective of this project is to conduct basic research on how people receive, evaluate, and form positions on scientific information and its relationship to low-dose radiation exposure. There are three major areas of study in our research program. First is the development of theories, frameworks and concepts essential to guiding data collection and analysis. The second area is a program of experimental studies on risk perception, evaluation of science information, and the structure of individual positions regarding low-dose exposures. Third is the community-level studies to examine and record how the social conditions, under which science communications take place, influence the development of attitudes and opinions about: low-dose exposures, the available management options, control of radiation risks, and preferences for program and policy goals

  2. Exposure to low doses of ionizing radiations

    International Nuclear Information System (INIS)

    Le Guen, B.

    2008-01-01

    The author discusses the knowledge about the effects of ionizing radiations on mankind. Some of them have been well documented (skin cancer and leukaemia for the pioneer scientists who worked on radiations, some other types of cancer for workers who handled luminescent paints, rock miners, nuclear explosion survivors, patients submitted to radiological treatments). He also evokes the issue of hereditary cancers, and discusses the issue of low dose irradiation where some surveys can now be performed on workers. He discusses the biological effects of these low doses. He outlines that many questions remain about these effects, notably the influence of dose level and of dose rate level on the biological reaction

  3. Biological influence from low dose and low-dose rate radiation

    International Nuclear Information System (INIS)

    Magae, Junji

    2007-01-01

    Although living organisms have defense mechanisms for radioadaptive response, the influence is considered to vary qualitatively and quantitatively for low dose and high dose, as well as for low-dose rate and high-dose rate. This article describes the bioresponse to low dose and low-dose rate. Among various biomolecules, DNA is the most sensitive to radiation, and accurate replication of DNA is an essential requirement for the survival of living organisms. Also, the influence of active enzymes resulted from the effect of radiation on enzymes in the body is larger than the direct influence of radiation on the body. After this, the article describes the carcinogenic risk by low-dose radiation, and then so-called Hormesis effect to create cancer inhibition effect by stimulating active physiology. (S.K.)

  4. Carcinogenesis induced by low-dose radiation

    Directory of Open Access Journals (Sweden)

    Piotrowski Igor

    2017-11-01

    Full Text Available Although the effects of high dose radiation on human cells and tissues are relatively well defined, there is no consensus regarding the effects of low and very low radiation doses on the organism. Ionizing radiation has been shown to induce gene mutations and chromosome aberrations which are known to be involved in the process of carcinogenesis. The induction of secondary cancers is a challenging long-term side effect in oncologic patients treated with radiation. Medical sources of radiation like intensity modulated radiotherapy used in cancer treatment and computed tomography used in diagnostics, deliver very low doses of radiation to large volumes of healthy tissue, which might contribute to increased cancer rates in long surviving patients and in the general population. Research shows that because of the phenomena characteristic for low dose radiation the risk of cancer induction from exposure of healthy tissues to low dose radiation can be greater than the risk calculated from linear no-threshold model. Epidemiological data collected from radiation workers and atomic bomb survivors confirms that exposure to low dose radiation can contribute to increased cancer risk and also that the risk might correlate with the age at exposure.

  5. Stimulation of seeds by low dose irradiation

    International Nuclear Information System (INIS)

    Lawson, Helen

    1976-05-01

    The first section of the bibliography lists materials on the stimulation of seeds by low dose irradiation, with particular reference to stimulation of germination and yield. The second section contains a small number of selected references on seed irradiation facilities. (author)

  6. Effect of low doses of ionizing radiation on human health

    International Nuclear Information System (INIS)

    Kovalenko, A.N.

    1990-01-01

    Data are reported on the possible mechanism of biological effects of low doses of ionizing radiation on the human body. The lesioning effect of this radiation resulted in some of the persons in the development of disorders of the function of information and vegetative-regulatory systems determined as a desintegration syndrome. This syndrome is manifested in unspecific neuro-vegetative disorders of the function of most important physiological and homeostatic system of the body leading to weakening of the processes of compensation and adaptation. This condition is characterized by an unspecific radiation syndrome as distinct from acute or chronic radiation disease which is a specific radiation syndrome

  7. Mammography-oncogenecity at low doses

    International Nuclear Information System (INIS)

    Heyes, G J; Mill, A J; Charles, M W

    2009-01-01

    Controversy exists regarding the biological effectiveness of low energy x-rays used for mammography breast screening. Recent radiobiology studies have provided compelling evidence that these low energy x-rays may be 4.42 ± 2.02 times more effective in causing mutational damage than higher energy x-rays. These data include a study involving in vitro irradiation of a human cell line using a mammography x-ray source and a high energy source which matches the spectrum of radiation observed in survivors from the Hiroshima atomic bomb. Current radiation risk estimates rely heavily on data from the atomic bomb survivors, and a direct comparison between the diagnostic energies used in the UK breast screening programme and those used for risk estimates can now be made. Evidence highlighting the increase in relative biological effectiveness (RBE) of mammography x-rays to a range of x-ray energies implies that the risks of radiation-induced breast cancers for mammography x-rays are potentially underestimated by a factor of four. A pooled analysis of three measurements gives a maximal RBE (for malignant transformation of human cells in vitro) of 4.02 ± 0.72 for 29 kVp (peak accelerating voltage) x-rays compared to high energy electrons and higher energy x-rays. For the majority of women in the UK NHS breast screening programme, it is shown that the benefit safely exceeds the risk of possible cancer induction even when this higher biological effectiveness factor is applied. The risk/benefit analysis, however, implies the need for caution for women screened under the age of 50, and particularly for those with a family history (and therefore a likely genetic susceptibility) of breast cancer. In vitro radiobiological data are generally acquired at high doses, and there are different extrapolation mechanisms to the low doses seen clinically. Recent low dose in vitro data have indicated a potential suppressive effect at very low dose rates and doses. Whilst mammography is a low

  8. New risk estimates at low doses

    International Nuclear Information System (INIS)

    Fry, R.J.M.

    1992-01-01

    The age of molecular radiation epidemiology may be at hand. The techniques are available to establish with the degree of precision required to determine whether agent-specific mutations can be identified consistently. A concerted effort to examine radiation-induced changes in as many relevant genes as possible appears to be justified. Cancers in those exposed to low doses of ionizing radiation should be chosen for the investigation. Parallel studies of radiation-induced cancers in experimental animals would not only complement the human studies, but perhaps reveal approaches to extrapolation of risk estimates across species. A caveat should be added to this optimistic view of what molecular studies might contribute to the knotty problem of risk estimates at low doses. The suggestions are made by one with no expertise in the field of molecular biology

  9. Cytogenetic effects of low-dose radiation

    International Nuclear Information System (INIS)

    Metalli, P.

    1983-01-01

    The effects of ionizing radiation on chromosomes have been known for several decades and dose-effect relationships are also fairly well established in the mid- and high-dose and dose-rate range for chromosomes of mammalian cells. In the range of low doses and dose rates of different types of radiation few data are available for direct analysis of the dose-effect relationships, and extrapolation from high to low doses is still the unavoidable approach in many cases of interest for risk assessment. A review is presented of the data actually available and of the attempts that have been made to obtain possible generalizations. Attention is focused on some specific chromosomal anomalies experimentally induced by radiation (such as reciprocal translocations and aneuploidies in germinal cells) and on their relevance for the human situation. (author)

  10. Epigenomic Adaptation to Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gould, Michael N. [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-30

    The overall hypothesis of this grant application is that the adaptive responses elicited by low dose ionizing radiation (LDIR) result in part from heritable DNA methylation changes in the epigenome. In the final budget period at the University of Wisconsin-Madison, we will specifically address this hypothesis by determining if the epigenetically labile, differentially methylated regions (DMRs) that regulate parental-specific expression of imprinted genes are deregulated in agouti mice by low dose radiation exposure during gestation. This information is particularly important to ascertain given the 1) increased human exposure to medical sources of radiation; 2) increased number of people predicted to live and work in space; and 3) enhanced citizen concern about radiation exposure from nuclear power plant accidents and terrorist ‘dirty bombs.’

  11. Radiation effects of high and low doses

    International Nuclear Information System (INIS)

    El-Naggar, A.M.

    1998-01-01

    The extensive proliferation of the uses and applications of atomic and nuclear energy resulted in possible repercussions on human health. The prominent features of the health hazards that may be incurred after exposure to high and low radiation doses are discussed. The physical and biological factors involved in the sequential development of radiation health effects and the different cellular responses to radiation injury are considered. The main criteria and features of radiation effects of high and low doses are comprehensively outlined

  12. Estimation of radiation risks at low dose

    International Nuclear Information System (INIS)

    1990-04-01

    The report presents a review of the effects caused by radiation in low doses, or at low dose rates. For the inheritable (or ''genetic''), as well as for the cancer producing effects of radiation, present evidence is consistent with: (a) a non-linear relationship between the frequency of at least some forms of these effects, with comparing frequencies caused by doses many times those received annually from natural sources, with those caused by lower doses; (b) a probably linear relationship, however, between dose and frequency of effects for dose rates in the region of that received from natural sources, or at several times this rate; (c) no evidence to indicate the existence of a threshold dose below which such effects are not produced, and a strong inference from the mode of action of radiation on cells at low dose rates that no such thresholds are likely to apply to the detrimental, cancer-producing or inheritable, effects resulting from unrepaired damage to single cells. 19 refs

  13. Deep learning for low-dose CT

    Science.gov (United States)

    Chen, Hu; Zhang, Yi; Zhou, Jiliu; Wang, Ge

    2017-09-01

    Given the potential risk of X-ray radiation to the patient, low-dose CT has attracted a considerable interest in the medical imaging field. Currently, the main stream low-dose CT methods include vendor-specific sinogram domain filtration and iterative reconstruction algorithms, but they need to access raw data whose formats are not transparent to most users. Due to the difficulty of modeling the statistical characteristics in the image domain, the existing methods for directly processing reconstructed images cannot eliminate image noise very well while keeping structural details. Inspired by the idea of deep learning, here we combine the autoencoder, deconvolution network, and shortcut connections into the residual encoder-decoder convolutional neural network (RED-CNN) for low-dose CT imaging. After patch-based training, the proposed RED-CNN achieves a competitive performance relative to the-state-of-art methods. Especially, our method has been favorably evaluated in terms of noise suppression and structural preservation.

  14. Low doses of gamma radiation in soybean

    International Nuclear Information System (INIS)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C.; Arthur, Valter; Arthur, Paula B.; Franco, Caio H.

    2017-01-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  15. Modification of damage following low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Nelson, J.M.; Metting, N.F.

    1988-01-01

    At very low doses the damage-interaction mechanism is responsible for very little lethal or potentially lethal damage, and repair of the latter should essentially disappear. An alternative model suggests that potentially lethal damage is either repaired with a constant half time or misrepaired at a rate which is proportional to the square of the damage concentration. In this case, as the dose decreases, the probability of misrepair decreases faster than the probability of repair, and repair becomes a more pronounced feature of the cell response. Since the consequence of unrepaired damage is an important question in determining the effects of low doses of radiation delivered at low dose rates, we have attempted to determine which of these two types of models is consistent with the response of plateau-phase CHO cells. In the earlier experiments, there was no indication of repair after a 50-rad exposure with a 24-hour split dose or plating delay; in fact, immediate plating resulted in survival slightly above control and delayed plating in survival slightly below the control value

  16. Low doses of gamma radiation in soybean

    Energy Technology Data Exchange (ETDEWEB)

    Franco, José G.; Franco, Suely S.H.; Villavicencio, Anna L.C., E-mail: zegilmar60@gmail.com, E-mail: gilmita@uol.com.br, E-mail: villavic@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Arthur, Valter; Arthur, Paula B., E-mail: arthur@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Franco, Caio H. [Universidade Federal de São Paulo (UNIFESP), SP (Brazil). Departamento de Microbiologia, Imunologia e Parasitologia

    2017-07-01

    The degree of radiosensitivity depends mostly on the species, the stage of the embryo at irradiation, the doses employed and the criteria used to measure the effect. One of the most common criteria to evaluate radiosensitivity in seeds is to measure the average plant production. Dry soya seeds were exposed to low doses of gamma radiation from source of Cobalt-60, type Gammecell-220, at 0.210 kGy dose rate. In order to study stimulation effects of radiation on germination, plant growth and production. A treatment with four radiation doses was applied as follows: 0 (control); 12.5; 25.0 and 50.0 Gy. Seed germination and harvested of number of seeds and total production were assessed to identify occurrence of stimulation. Soya seeds number and plants were handled as for usual seed production in Brazil. The low doses of gamma radiation in the seeds that stimulate the production were the doses of 12.5 and 50.0 Gy. The results show that the use of low doses of gamma radiation can stimulate germination and plant production. (author)

  17. Biological effects of low doses of radiation at low dose rate

    International Nuclear Information System (INIS)

    1996-05-01

    The purpose of this report was to examine available scientific data and models relevant to the hypothesis that induction of genetic changes and cancers by low doses of ionizing radiation at low dose rate is a stochastic process with no threshold or apparent threshold. Assessment of the effects of higher doses of radiation is based on a wealth of data from both humans and other organisms. 234 refs., 26 figs., 14 tabs

  18. Plants as warning signal for exposure to low dose radiation

    International Nuclear Information System (INIS)

    Rusli Ibrahim; Norhafiz Talib

    2012-01-01

    The stamen-hair system of Tradescantia for flower colour has proven to be one of the most suitable materials to study the frequency of mutations induced by low doses of various ionizing radiations and chemical mutagens. The system has also been used successfully for detecting mutagenic synergisms among chemical mutagens and ionizing radiations as well as for studying the variations of spontaneous mutation frequency. In this study of radiobiology, the main objective is to observe somatic mutation (occurrence of pink cells from blue cells) induced on stamen hairs of five Tradescantia sp. available in Malaysia after exposure to low doses of chronic gamma irradiation using Gamma Green House. Pink cells appeared only on Tradescantia Pallida Purpurea stamen hairs after 13 days of exposure to irradiation with different doses of gamma rays. The highest number of stamens with pink cells was recorded from flowers irradiated with the highest dose of 6.37 Gy with 0.07 Gy/ h of dose rate. The lowest number of stamens with pink cells was recorded with an average of 0.57, irradiated with the lowest dose of 0.91 Gy with 0.01 Gy/ h of dose rate. There were no pink cells observed on Tradescantia Spathaceae Discolor after exposure to different doses of gamma rays. Similar negative results were observed for the control experiments. The principal cells in this assay are the mitotic stamen hair cells developing in the young flower buds. After exposure to radiation, the heterozygous dominant blue character of the stamen hair cell is prevented, resulting in the appearance of the recessive pink color. Furthermore, no pink cell appears on all species of Tradescantia spathaceae after irradiated with different doses of gamma rays. The sensitivity of the Tradescantia has been used widely and has demonstrated the relation between radiation dose and frequency of mutation observed at low doses which can contribute to the effects of low doses and their consequences for human health. This system

  19. Low-dose aripiprazole for refractory burning mouth syndrome

    Directory of Open Access Journals (Sweden)

    Umezaki Y

    2016-05-01

    Full Text Available Yojiro Umezaki,1 Miho Takenoshita,2 Akira Toyofuku2 1Psychosomatic Dentistry Clinic, Dental Hospital, 2Psychosomatic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan Abstract: We report a case of refractory burning mouth syndrome (BMS ameliorated with low dose of aripiprazole. The patient was a 66-year-old female who had suffered from chronic burning pain in her tongue for 13 months. No abnormality associated with the burning sensation was detected in the laboratory tests and the oral findings. Considering the clinical feature and the history together, we diagnosed the burning sensation as BMS. The BMS pain was decreased by aripiprazole (powder 1.0 mg/d, though no other antidepressants had satisfying pain relief. It could be supposed that the efficacy of aripiprazole is caused by dopamine stabilization in this case, and BMS might have a subtype that is reactive to aripiprazole. Further studies are needed to confirm the efficacy of aripiprazole for BMS. Keywords: burning mouth syndrome, low-dose aripiprazole, chronic pain

  20. Metabolomics: new prospects in low-dose radio-toxicology

    International Nuclear Information System (INIS)

    Souidi, Maamar; Grison, Stephane

    2014-01-01

    There is recurring public concern regarding the health impact of chronic exposure to low-dose ionizing radiation. This concern is further heightened when possible sources of exposure are identified, such as disused mines, the operation of nuclear facilities and radioactive waste disposal facilities, accidental release from fuel cycle facilities or the possible return of residents to areas contaminated following a reactor accident, such as the one that occurred at Fukushima. In keeping with the guidelines set out in the European strategic research agenda for MELODI, IRSN is conducting an extensive, largely experiment-based, research program to acquire scientific data to respond to this concern. The program has already revealed that chronic ingestion of cesium-137 or uranium induces many subtle, generally slight, metabolic changes, the overall biological effects of which remain to be studied. A recent 'broad-spectrum' analytical technique known as metabolomics was used to pinpoint these metabolic changes. (authors)

  1. Harderian Gland Tumorigenesis: Low-Dose and LET Response

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Polly Y. [SRI International, Menlo Park, CA (United States). Biosciences Div.; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Cucinotta, Francis A. [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Health Physics and Diagnostic Sciences; Bjornstad, Kathleen A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Bakke, James [SRI International, Menlo Park, CA (United States). Biosciences Div.; Rosen, Chris J. [SRI International, Menlo Park, CA (United States). Biosciences Div.; Du, Nicholas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Fairchild, David G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.; Cacao, Eliedonna [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Health Physics and Diagnostic Sciences; Blakely, Eleanor A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Life Sciences Div.

    2016-04-19

    Increased cancer risk remains a primary concern for travel into deep space and may preclude manned missions to Mars due to large uncertainties that currently exist in estimating cancer risk from the spectrum of radiations found in space with the very limited available human epidemiological radiation-induced cancer data. Existing data on human risk of cancer from X-ray and gamma-ray exposure must be scaled to the many types and fluences of radiations found in space using radiation quality factors and dose-rate modification factors, and assuming linearity of response since the shapes of the dose responses at low doses below 100 mSv are unknown. The goal of this work was to reduce uncertainties in the relative biological effect (RBE) and linear energy transfer (LET) relationship for space-relevant doses of charged-particle radiation-induced carcinogenesis. The historical data from the studies of Fry et al. and Alpen et al. for Harderian gland (HG) tumors in the female CB6F1 strain of mouse represent the most complete set of experimental observations, including dose dependence, available on a specific radiation-induced tumor in an experimental animal using heavy ion beams that are found in the cosmic radiation spectrum. However, these data lack complete information on low-dose responses below 0.1 Gy, and for chronic low-dose-rate exposures, and there are gaps in the LET region between 25 and 190 keV/μm. In this study, we used the historical HG tumorigenesis data as reference, and obtained HG tumor data for 260 MeV/u silicon (LET ~70 keV/μm) and 1,000 MeV/u titanium (LET ~100 keV/μm) to fill existing gaps of data in this LET range to improve our understanding of the dose-response curve at low doses, to test for deviations from linearity and to provide RBE estimates. Animals were also exposed to five daily fractions of 0.026 or 0.052 Gy of 1,000 MeV/u titanium ions to simulate chronic exposure, and HG tumorigenesis from this fractionated study were compared to the

  2. Bioavailability of diclofenac potassium at low doses

    Science.gov (United States)

    Hinz, Burkhard; Chevts, Julia; Renner, Bertold; Wuttke, Henrike; Rau, Thomas; Schmidt, Andreas; Szelenyi, Istvan; Brune, Kay; Werner, Ulrike

    2005-01-01

    Aim Diclofenac-K has been recently launched at low oral doses in different countries for over-the-counter use. However, given the considerable first-pass metabolism of diclofenac, the degree of absorption of diclofenac-K at low doses remained to be determined. The aim of this study was to determine the bioavailability of low-dose diclofenac-K. Methods A randomized, three-way, cross-over study was performed in 10 subjects. Each received diclofenac-K, 22.5 mg via short-term i.v. infusion and orally at single doses of 12.5 mg and 25 mg. Results Mean (± SD) times to maximal plasma concentration (tmax) of diclofenac were 0.48 ± 0.28 h (12.5 mg) and 0.93 ± 0.96 h (25 mg). The absolute bioavailability of diclofenac-K after oral administration did not differ significantly in the 12.5-mg and 25-mg dose group (63.1 ± 12.6% vs. 65.1 ± 19.4%, respectively). The 90% confidence intervals for the AUC∞ and AUCt ratios for the two oral regimes were 82.6, 103.4% (point estimate 92.4%) and 86.2, 112.9% (point estimate 98.6%), respectively. These values were within the acceptance criteria for bioequivalence (80–125%). Conclusions Our data indicate that diclofenac-K is rapidly and well absorbed at low dose, and are consistent with a rapid onset of action of the drug. Abbreviations AUC, area under plasma concentraton-time curve; Cmax, peak plasma concentration; CI, confidence interval; COX, cyclooxygenase; D, dose; F, absolute bioavailability; tmax, time to reach Cmax. PMID:15606444

  3. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    Ionizing radiation of cosmic or terrestrial origin is part of the environment in which all living things have evolved since the creation of the universe. The artificial radioactivity generated by medical diagnostic and treatment techniques, some industrial activities, radioactive fallout, etc. has now been added to this natural radioactivity. This article reviews the biological effects of the low doses of ionizing radiation to which the population is thus exposed. Their carcinogenic risk cannot simply be extrapolated from what we know about high-dose exposure. (author)

  4. Low dose radiation and diabetes mellitus

    International Nuclear Information System (INIS)

    Zhao Hongguang; Gong Shouliang; Cai Lu

    2006-01-01

    Induction of hormesis and adaptive response by low-dose radiatio (LDR) has been extensively indicated. It's mechanism may be related with the protective protein and antioxidants that LDR induced, which take effects on the diabetes mellitus (DM) and other diseases. This review will summarize available dat with emphasis on three points: the preventive effect of LDR on the development of diabetes, the therapeutic effect of LDR on diabetic complications and possible mechanisms by which LDR prevents the development of diabetes and diabetic complications. Finally, the perspectives of LDR clinical, diabetes-related implication are discussed. (authors)

  5. Direct or photostimulated luminescence after X-Ray irradiation of divalent europium in alkaline earth compounds containing some halides; Luminescence directe ou photostimulee apres irradiation X de l'europium divalent dans des familles de composes alcalino-terreux comportant un halogene

    Energy Technology Data Exchange (ETDEWEB)

    Merigou, C

    1990-10-15

    With a view for digitizing of radiological images, the luminescent properties of divalent europium in diverse halogen compounds involving strontium or barium have been studied. In halogen-rich compounds (MCl{sub 2}, M{sub 4}OCl{sub 6}, M{sub 5}SiO{sub 4}Cl{sub 6},... where M is Sr or Ba), the thermal extinction of the emission begins only above 300 K. High densities of coloured spots have been produced with X-ray irradiation. The combining of these 2 features has led to the obtention of high yields for argon laser stimulated luminescence in the case of Sr{sub 5}SiO{sub 4}Cl{sub 5}Br:Eu halogen silicate. Although these yields are high they stay below that of BaXF:Eu which is usually used in photon-stimulated screens.

  6. Low-dose effect on blood chromosomes

    International Nuclear Information System (INIS)

    Pohl-Rueling, J.

    1992-01-01

    Linear dose response relationships of biological effects at low doses are experimentally and theoretically disputed. Structural chromosome aberration rates at doses ranging from normal background exposures up to about 30 mGy/yr in vivo and up to 50 mGy in vitro were investigated by the author and other scientists. Results are comparable and dose effect curves reveal following shapes; within the normal burden and up to 2-10 mGy/yr in vivo rates they increase sharply to about 3-6 times the lowest values; subsequent doses either from natural, occupational or accidental exposures up to about 30 mGy/yr yield either constant aberration rates, assuming a plateau, or perhaps even a decrease. In vitro experiments show comparable results up to 50 mGy. Other biological effects seem to have similar dose dependencies. The non-linearity of low-dose effects can be explained by induction of repair enzymes at certain damage to the DNA. This hypothesis is sustained experimentally and theoretically by several papers in literature. (author). 14 refs., 5 figs

  7. Low and very low doses, new recommendations?

    International Nuclear Information System (INIS)

    Foucher, N.

    1999-01-01

    The topic of the seminar organized by the world council of nuclear workers (WONUC) was the effects of low or very low doses on human health. Discussions centred round the linearity of the relation between dose and effect in the evaluation and management of the health hazard. The recommendations proposed by ICPR (international commission for radiological protection) are based on this linearity as a precaution. On the one hand it is remembered that low dose irradiation might be beneficial. It has been proved that the irradiation of the whole body is efficient in case of Hodgkin lymphoma. On the other hand it is remembered that doses as low as 10 mSv in utero have led to an excess of cancer in children. Studies based on experimentally radio-induced cancers have been carried out in Japan, China, Canada and France.Their results seem to be not consistent with the hypothesis of linearity. During the last decade a lot of work has been made but a conclusion is far to be reached, it is said that the American department of energy (DOE) has invited bids in 1999 to launch research programs in order to clarify the situation. (A.C.)

  8. Clinical characteristic of epidemic hepatitis in case of the effect of low dose irradiation

    International Nuclear Information System (INIS)

    Geras'kov, O.P.; Shubik, V.M.

    1990-01-01

    Clinical course of infections hepatitics B, developed on the background of pulmonary tuberculosis in people, who were subjected to chronic low dose ionizing radiation, indicated more frequent cases of severe and medium-severe forms of morbidity as compared to non-irradiated patients and those with no comitant pulmonary tuberculosis. However the reconvalescence terms, hepatitis size normalization, urine colour in different group patients did not differ essentially. The data obtained testify to the absence of significant peculiarities in the course of infections hepatitis B, combined with pulmonar tuberculosis under conditions of chronic low dose ionizing radiation. 3 refs.; 3 tabs

  9. Biological Effects of Low-Dose Exposure

    CERN Document Server

    Komochkov, M M

    2000-01-01

    On the basis of the two-protection reaction model an analysis of stochastic radiobiological effects of low-dose exposure of different biological objects has been carried out. The stochastic effects are the results published in the last decade: epidemiological studies of human cancer mortality, the yield of thymocyte apoptosis of mice and different types of chromosomal aberrations. The results of the analysis show that as dependent upon the nature of biological object, spontanous effect, exposure conditions and radiation type one or another form dose - effect relationship is realized: downwards concave, near to linear and upwards concave with the effect of hormesis included. This result testifies to the incomplete conformity of studied effects of 1990 ICRP recomendations based on the linear no-threshold hypothesis about dose - effect relationship. Because of this the methodology of radiation risk estimation recomended by ICRP needs more precisian and such quantity as collective dose ought to be classified into...

  10. Low Dose Ionizing Radiation Modulates Immune Function

    International Nuclear Information System (INIS)

    Nelson, Gregory A.

    2016-01-01

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a 'Th2 polarized' immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in

  11. Low Dose Ionizing Radiation Modulates Immune Function

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Gregory A. [Loma Linda Univ., CA (United States)

    2016-01-12

    In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses from 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the

  12. Low-dose aripiprazole for refractory burning mouth syndrome.

    Science.gov (United States)

    Umezaki, Yojiro; Takenoshita, Miho; Toyofuku, Akira

    2016-01-01

    We report a case of refractory burning mouth syndrome (BMS) ameliorated with low dose of aripiprazole. The patient was a 66-year-old female who had suffered from chronic burning pain in her tongue for 13 months. No abnormality associated with the burning sensation was detected in the laboratory tests and the oral findings. Considering the clinical feature and the history together, we diagnosed the burning sensation as BMS. The BMS pain was decreased by aripiprazole (powder) 1.0 mg/d, though no other antidepressants had satisfying pain relief. It could be supposed that the efficacy of aripiprazole is caused by dopamine stabilization in this case, and BMS might have a subtype that is reactive to aripiprazole. Further studies are needed to confirm the efficacy of aripiprazole for BMS.

  13. State of human genome at low-doses ecological influences

    International Nuclear Information System (INIS)

    Mel'nov, S.B.; Rytik, P.G.; Kruchinskij, N.G.; Kovalev, V.A.; Palamar, L.A.; Senyuk, O.F.

    2005-01-01

    The results of analysis of the state of genome (amounts of single strand breaks in DNA) of the persons exposed to influence of complex 'Chernobyl factor' in remote terms after a failure on ChNPP are resulted. Findings allowed to expose the increase of level of single strand breaks in DNA at the chronically irradiated persons mainly carry adaptive character and probably can be related to instability of genome. Thus at organism level growth of mutational pressure and strengthening of instability of cellular genome is related to the change of spectrum of biological characteristics, in particular individual reaction of somatic cells of victims on additional mutagens influences. The indicated changes can testify to existence of potential risk of remote genetic consequences of long-term irradiation influence in low doses

  14. Genetic effects of low-dose irradiation in Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Zajnulin, V.G.; Shaposhnikov, M.V.; Yuraneva, I.N.

    2000-01-01

    Influence of chronic γ-irradiation at the dose rate of 0.17 cGy/h on the rate of genetic variability in the laboratory strains of Drosophila Melanogaster with genotypic distinguishes by families of mobile genetic elements and of systems of hybrid disgenesis and also violations in reparation processes control mechanisms. It was shown that the rates of induction of recessive lethal mutations depended on genotype of investigated strains. In the different strains an increase as well as a decrease of the mutation rate were observed. Also in was established that irradiation leads to the increase in frequencies of the gonads sterility and mutability of the sn w and h(w + ) in the P-M and H-E dysgenic crosses. Obtained results suggest that mobile genetic elements play an important role in the forming of genetic effects in response to low dose irradiation [ru

  15. Multidisciplinary European Low Dose Initiative (MELODI). Strategic research agenda for low dose radiation risk research

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M. [Federal Office for Radiation Protection, BfS, Department of Radiation Protection and Health, Neuherberg (Germany); Auvinen, A. [University of Tampere, Tampere (Finland); STUK, Helsinki (Finland); Cardis, E. [ISGlobal, Barcelona Institute for Global Health, Barcelona (Spain); Durante, M. [Institute for Fundamental Physics and Applications, TIFPA, Trento (Italy); Harms-Ringdahl, M. [Stockholm University, Centre for Radiation Protection Research, Stockholm (Sweden); Jourdain, J.R. [Institute for Radiological Protection and Nuclear Safety, IRSN, Fontenay-aux-roses (France); Madas, B.G. [MTA Centre for Energy Research, Environmental Physics Department, Budapest (Hungary); Ottolenghi, A. [University of Pavia, Physics Department, Pavia (Italy); Pazzaglia, S. [Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Rome (Italy); Prise, K.M. [Queens University Belfast, Belfast (United Kingdom); Quintens, R. [Belgian Nuclear Research Centre, SCK-CEN, Mol (Belgium); Sabatier, L. [French Atomic Energy Commission, CEA, Paris (France); Bouffler, S. [Public Health England, PHE, Chilton (United Kingdom)

    2018-03-15

    MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website (http://www.melodi-online.eu/sra.html). (orig.)

  16. Advanced Computational Approaches for Characterizing Stochastic Cellular Responses to Low Dose, Low Dose Rate Exposures

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Bobby, R., Ph.D.

    2003-06-27

    OAK - B135 This project final report summarizes modeling research conducted in the U.S. Department of Energy (DOE), Low Dose Radiation Research Program at the Lovelace Respiratory Research Institute from October 1998 through June 2003. The modeling research described involves critically evaluating the validity of the linear nonthreshold (LNT) risk model as it relates to stochastic effects induced in cells by low doses of ionizing radiation and genotoxic chemicals. The LNT model plays a central role in low-dose risk assessment for humans. With the LNT model, any radiation (or genotoxic chemical) exposure is assumed to increase one¡¯s risk of cancer. Based on the LNT model, others have predicted tens of thousands of cancer deaths related to environmental exposure to radioactive material from nuclear accidents (e.g., Chernobyl) and fallout from nuclear weapons testing. Our research has focused on developing biologically based models that explain the shape of dose-response curves for low-dose radiation and genotoxic chemical-induced stochastic effects in cells. Understanding the shape of the dose-response curve for radiation and genotoxic chemical-induced stochastic effects in cells helps to better understand the shape of the dose-response curve for cancer induction in humans. We have used a modeling approach that facilitated model revisions over time, allowing for timely incorporation of new knowledge gained related to the biological basis for low-dose-induced stochastic effects in cells. Both deleterious (e.g., genomic instability, mutations, and neoplastic transformation) and protective (e.g., DNA repair and apoptosis) effects have been included in our modeling. Our most advanced model, NEOTRANS2, involves differing levels of genomic instability. Persistent genomic instability is presumed to be associated with nonspecific, nonlethal mutations and to increase both the risk for neoplastic transformation and for cancer occurrence. Our research results, based on

  17. Low dose irradiation facilitates hepatocellular carcinoma genesis involving HULC.

    Science.gov (United States)

    Li, Yuan; Ge, Chang; Feng, Guoxing; Xiao, Huiwen; Dong, Jiali; Zhu, Changchun; Jiang, Mian; Cui, Ming; Fan, Saijun

    2018-03-24

    Irradiation exposure positive correlates with tumor formation, such as breast cancer and lung cancer. However, whether low dose irradiation induces hepatocarcinogenesis and the underlying mechanism remain poorly defined. In the present study, we reported that low dose irradiation facilitated the proliferation of hepatocyte through up-regulating HULC in vitro and in vivo. Low dose irradiation exposure elevated HULC expression level in hepatocyte. Deletion of heightened HULC erased the cells growth accelerated following low dose irradiation exposure. CDKN1, the neighbor gene of HULC, was down-regulated by overexpression of HULC following low dose irradiation exposure via complementary base pairing, resulting in promoting cell cycle process. Thus, our findings provide new insights into the mechanism of low dose irradiation-induced hepatocarcinogenesis through HULC/CDKN1 signaling, and shed light on the potential risk of low dose irradiation for the development of hepatocellular carcinoma in pre-clinical settings. © 2018 Wiley Periodicals, Inc.

  18. low dose irradiation growth in zirconium

    International Nuclear Information System (INIS)

    Fortis, A.M.

    1987-01-01

    Low dose neutron irradiation growth in textured and recrystallized zirconium, is studied, at the Candu Reactors Calandria temperature (340 K) and at 77 K. It was necessary to design and build 1: A facility to irradiate at high temperatures, which was installed in the Argentine Atomic Energy Commission's RA1 Reactor; 2: Devices to carry out thermal recoveries, and 3: Devices for 'in situ' measurements of dimensional changes. The first growth kinetics curves were obtained at 365 K and at 77 K in a cryostat under neutron fluxes of similar spectra. Irradiation growth experiments were made in zirconium doped with fissionable material (0,1 at % 235 U). In this way an equivalent dose two orders of magnitude greater than the reactor's fast neutrons dose was obtained, significantly reducing the irradiation time. The specimens used were bimetallic couples, thus obtaining a great accuracy in the measurements. The results allow to determine that the dislocation loops are the main cause of irradiation growth in recrystallized zirconium. Furthermore, it is shown the importance of 'in situ' measurements as a way to avoid the effect that temperature changes have in the final growth measurement; since they can modify the residual stresses and the overconcentrations of defects. (M.E.L.) [es

  19. Very low dose and dose-rate X-ray induced adaptive response in human lymphocytes at various cell cycle stages against bleomycin induced chromatid aberrations

    International Nuclear Information System (INIS)

    Hossein Mozdarani; Moghadam, R.N.

    2007-01-01

    Complete text of publication follows. Objective: To study the adaptive response induced by very low doses of X-rays at very low dose rate in human lymphocytes at different cell cycle stages followed by a challenge dose of bleomycin sulphate at G2 phase. Materials and Methods: Human peripheral blood lymphocytes before (G0) and after PHA stimulation (G1 and G2) were exposed to 1 and 5 cGy X-rays generated by a fluoroscopy unit with a dose rate of 5.56 mGy/min and challenged with 5 μg/ml bleomycin sulphate (BLM) 48 hours after culture initiation. Mitotic cells were arrested at metaphase by addition of colcemid in cultures 1.5 h before harvesting. Harvesting and slide preparation was performed using standard method. 100 well spread metaphases were analyzed for the presence of chromatid type aberrations for each sample. Results: Results obtained indicate that there is a linear relationship between the dose of BLM and chromatid aberrations below 5 μg/ml (R=0.93, p<0.0001). The results also show that pretreatment of lymphocytes with low dose X-rays at G0, G1 and G2 phases of the cell cycle significantly reduced the sensitivity of lymphocytes to the clastogenic effects of BLM in G2. Much lower frequencies of chromatid aberrations were observed in X-ray irradiated lymphocytes following BLM treatment (p<0.05). The magnitudes of adaptation induced at different phases of the cell cycle were not significantly different. Furthermore, there was no a significant difference in the magnitude of adaptive response induced by either 1 or 5 cGy X-rays. Conclusion: These observations might indicate that resistance of pre-exposure of lymphocytes to very low doses of X-rays protects them from clastogenic effects of BLM. This effect might be due to initial DNA damage induced in these cells leading to provocation of an active DNA repair mechanism independent of cell cycle stage.

  20. The health effects of low-dose ionizing radiation

    International Nuclear Information System (INIS)

    Dixit, A.N.; Dixit, Nishant

    2012-01-01

    It has been established by various researches, that high doses of ionizing radiation are harmful to health. There is substantial controversy regarding the effects of low doses of ionizing radiation despite the large amount of work carried out (both laboratory and epidemiological). Exposure to high levels of radiation can cause radiation injury, and these injuries can be relatively severe with sufficiently high radiation doses. Prolonged exposure to low levels of radiation may lead to cancer, although the nature of our response to very low radiation levels is not well known at this time. Many of our radiation safety regulations and procedures are designed to protect the health of those exposed to radiation occupationally or as members of the public. According to the linear no-threshold (LNT) hypothesis, any amount, however small, of radiation is potentially harmful, even down to zero levels. The threshold hypothesis, on the other hand, emphasizes that below a certain threshold level of radiation exposure, any deleterious effects are absent. At the same time, there are strong arguments, both experimental and epidemiological, which support the radiation hormesis (beneficial effects of low-level ionizing radiation). These effects cannot be anticipated by extrapolating from harmful effects noted at high doses. Evidence indicates an inverse relationship between chronic low-dose radiation levels and cancer incidence and/or mortality rates. Examples are drawn from: 1) state surveys for more than 200 million people in the United States; 2) state cancer hospitals for 200 million people in India; 3) 10,000 residents of Taipei who lived in cobalt-60 contaminated homes; 4) high-radiation areas of Ramsar, Iran; 5) 12 million person-years of exposed and carefully selected control nuclear workers; 6) almost 300,000 radon measurements of homes in the United States; and 7) non-smokers in high-radon areas of early Saxony, Germany. This evidence conforms to the hypothesis that

  1. Effects of low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Masse, R.

    2006-01-01

    Several groups of human have been irradiated by accidental or medical exposure, if no gene defect has been associated to these exposures, some radioinduced cancers interesting several organs are observed among persons exposed over 100 to 200 mSv delivered at high dose rate. Numerous steps are now identified between the initial energy deposit in tissue and the aberrations of cell that lead to tumors but the sequence of events and the specific character of some of them are the subject of controversy. The stake of this controversy is the risk assessment. From the hypothesis called linear relationship without threshold is developed an approach that leads to predict cancers at any tiny dose without real scientific foundation. The nature and the intensity of biological effects depend on the quantity of energy absorbed in tissue and the modality of its distribution in space and time. The probability to reach a target (a gene) associated to the cancerating of tissue is directly proportional to the dose without any other threshold than the quantity of energy necessary to the effect, its probability of effect can be a more complex function and depends on the quality of the damage produced as well as the ability of the cell to repair the damage. These two parameters are influenced by the concentration of initial injuries in the target so by the quality of radiation and by the dose rate. The mechanisms of defence explain the low efficiency of radiation as carcinogen and then the linearity of effects in the area of low doses is certainly the least defensible scientific hypothesis for the prediction of the risks. (N.C.)

  2. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  3. Low dose radiation enhances the Locomotor activity of D. melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Ki Moon; Lee, Buyng Sub; Nam Seon Young; Kim, Ji Young; Yang, Kwang Hee; Choi, Tae In; Kim, Cha Soon [Radiation Effect Research Team, Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd., Gyeongju (Korea, Republic of)

    2013-04-15

    Mild stresses at low level including radiation can induce the beneficial effects in many vertebrate and invertebrate species. However, a large amount of studies in radiation biology have focused on the detrimental effects of high dose radiation (HDR) such as the increased incidence of cancers and developmental diseases. Low dose radiation (LDR) induces biologically favorable effects in diverse fields, for example, cancer development, genomic instability, immune response, and longevity. Our previous data indicated that LDR promotes cells proliferation of which degree is not much but significant, and microarray data explained that LDR irradiated fruit flies showing the augmented immunity significantly changed the program for gene expression of many genes in Gene Ontology (GO) categories related to metabolic process. Metabolic process in development one of major contributors in organism growth, interbreeding, motility, and aging. Therefore, it is valuable to examine whether LDR change the physiological parameters related to metabolism, and how LDR regulates the metabolism in D. melanogaster. In this study, to investigate that LDR influences change of the metabolism, a representative parameter, locomotor activity. In addition, the activation of several cellular signal molecules was determined to investigate the specific molecular mechanism of LDR effects on the metabolism. We explored whether ionizing radiation affects the motility activity. We performed the RING assays to evaluate the locomotor activity, a representative parameter presenting motility of fruit flies. HDR dramatically decreased the motor activity of irradiated flies. Surprisingly, the irradiated flies at low dose radiation in both acute and chronic showed the significantly increased locomotor activity, compared to non-irradiated flies. Irradiation would induce change of the several signal pathways for flies to respond to it. The activation of some proteins involved in the cells proliferation and stress

  4. Effects of low dose mitomycin C on experimental tumor radiotherapy

    International Nuclear Information System (INIS)

    Yang Jianzheng; Liang Shuo; Qu Yaqin; Pu Chunji; Zhang Haiying; Wu Zhenfeng; Wang Xianli

    2001-01-01

    Objective: To evaluate the possibility of low dose mitomycin C(MMC) as an adjunct therapy for radiotherapy. Methods: Change in tumor size tumor-bearing mice was measured. Radioimmunoassay was used to determine immune function of mice. Results: Low dose Mac's pretreatment reduced tumor size more markedly than did radiotherapy only. The immune function in mice given with low dose MMC 12h before radiotherapy was obviously higher than that in mice subjected to radiotherapy only (P<0.05), and was close to that in the tumor-bearing mice before radiotherapy. Conclusion: Low dose MMC could improve the radiotherapy effect. Pretreatment with low dose MMC could obviously improve the immune suppression state in mice caused by radiotherapy. The mechanism of its improvement of radiotherapeutic effect by low dose of MMC might be due to its enhancement of immune function and induction of adaptive response in tumor-bearing mice

  5. Low-dose effects of hormones and endocrine disruptors.

    Science.gov (United States)

    Vandenberg, Laura N

    2014-01-01

    Endogenous hormones have effects on tissue morphology, cell physiology, and behaviors at low doses. In fact, hormones are known to circulate in the part-per-trillion and part-per-billion concentrations, making them highly effective and potent signaling molecules. Many endocrine-disrupting chemicals (EDCs) mimic hormones, yet there is strong debate over whether these chemicals can also have effects at low doses. In the 1990s, scientists proposed the "low-dose hypothesis," which postulated that EDCs affect humans and animals at environmentally relevant doses. This chapter focuses on data that support and refute the low-dose hypothesis. A case study examining the highly controversial example of bisphenol A and its low-dose effects on the prostate is examined through the lens of endocrinology. Finally, the chapter concludes with a discussion of factors that can influence the ability of a study to detect and interpret low-dose effects appropriately. © 2014 Elsevier Inc. All rights reserved.

  6. Recovery Profiles of T-Cell Subsets Following Low-Dose Total Body Irradiation and Improvement With Cinnamon

    International Nuclear Information System (INIS)

    Zheng, Xiaodan; Guo, Yuqi; Wang, Lei; Zhang, Honghai; Wang, Shaobo; Wang, Li; An, Lei; Zhou, Xianbin; Li, Xia; Yao, Chengfang

    2015-01-01

    Purpose: Inefficient T-cell reconstitution from x-ray–induced immune damage reduces antitumor response. To understand the profile of T-cell reconstitution after irradiation will overcome the barrier of antitumor immunity. This study aimed to identify the recovery profile of T-cell subsets following x-ray irradiation and to highlight the role of cinnamon on efficient T-cell restoration postexposure in the antitumor response. Methods and Materials: CD3"+, CD8"+, and CD4"+ T cells and Th1, Th2, Th17, and regulatory T (Treg) cells were evaluated at different time points after single low-dose total body irradiation (SLTBI) with or without cinnamon treatments. T-bet, GATA3, RORγt, and Foxp3 signaling specific for Th1, Th2, Th17, and Treg were also analyzed by RT-PCR assay. The effects of cinnamon on efficient T-cell subset reconstitution was confirmed in a lung melanoma model in irradiated mice. Results: Reconstitution of CD4"+ T cells was delayed more than that of CD8"+ T cells in T-cell restoration after SLTBI. The production of IFNγ by Th1 or Tc1 cells was sharply decreased and was accompanied by reduced T-bet mRNA, even when total T-cell numbers had recovered; the frequencies of Th17 and Treg cells and their specific transcription factors (RORγt and Foxp3, respectively) were obviously increased. Irradiation-induced inefficient T-cell reconstitution impaired the antitumor capacities in the lung melanoma model. Pretreatment with cinnamon in irradiated mice accelerated the generation of Th1 and reduced the differentiation of Treg cells by activating T-bet and limiting transcriptions of Foxp3. Improvement resulting from cinnamon pretreatment on the efficient T-cell recovery profile from SLTBI promoted antitumor immunity in the lung melanoma model. Conclusions: T-cell reconstitution from SLTBI was characterized by impaired Th1 and elevated Th17 and Treg cells. Cinnamon effectively improved the imbalance of T-cell subsets by promoting the proliferation of Th1 and

  7. Recovery Profiles of T-Cell Subsets Following Low-Dose Total Body Irradiation and Improvement With Cinnamon

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Xiaodan [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); School of Medicine and Life Science, University of Jinan-Shandong Academy of Medical Science, Jinan (China); Guo, Yuqi [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); Wang, Lei [Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan (China); Zhang, Honghai [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); Wang, Shaobo [Shandong University, Jinan (China); Wang, Li [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); An, Lei [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); School of Medicine and Life Science, University of Jinan-Shandong Academy of Medical Science, Jinan (China); Zhou, Xianbin; Li, Xia [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China); Yao, Chengfang, E-mail: yaocf9941@163.com [Key Laboratory for Tumor Immunology and Traditional Chinese Medicine Immunology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan (China)

    2015-12-01

    Purpose: Inefficient T-cell reconstitution from x-ray–induced immune damage reduces antitumor response. To understand the profile of T-cell reconstitution after irradiation will overcome the barrier of antitumor immunity. This study aimed to identify the recovery profile of T-cell subsets following x-ray irradiation and to highlight the role of cinnamon on efficient T-cell restoration postexposure in the antitumor response. Methods and Materials: CD3{sup +}, CD8{sup +}, and CD4{sup +} T cells and Th1, Th2, Th17, and regulatory T (Treg) cells were evaluated at different time points after single low-dose total body irradiation (SLTBI) with or without cinnamon treatments. T-bet, GATA3, RORγt, and Foxp3 signaling specific for Th1, Th2, Th17, and Treg were also analyzed by RT-PCR assay. The effects of cinnamon on efficient T-cell subset reconstitution was confirmed in a lung melanoma model in irradiated mice. Results: Reconstitution of CD4{sup +} T cells was delayed more than that of CD8{sup +} T cells in T-cell restoration after SLTBI. The production of IFNγ by Th1 or Tc1 cells was sharply decreased and was accompanied by reduced T-bet mRNA, even when total T-cell numbers had recovered; the frequencies of Th17 and Treg cells and their specific transcription factors (RORγt and Foxp3, respectively) were obviously increased. Irradiation-induced inefficient T-cell reconstitution impaired the antitumor capacities in the lung melanoma model. Pretreatment with cinnamon in irradiated mice accelerated the generation of Th1 and reduced the differentiation of Treg cells by activating T-bet and limiting transcriptions of Foxp3. Improvement resulting from cinnamon pretreatment on the efficient T-cell recovery profile from SLTBI promoted antitumor immunity in the lung melanoma model. Conclusions: T-cell reconstitution from SLTBI was characterized by impaired Th1 and elevated Th17 and Treg cells. Cinnamon effectively improved the imbalance of T-cell subsets by promoting the

  8. Endometrial safety of ultra-low-dose estradiol vaginal tablets

    DEFF Research Database (Denmark)

    Simon, James; Nachtigall, Lila; Ulrich, Lian G

    2010-01-01

    To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17ß-estradiol vaginal tablets in postmenopausal women with vaginal atrophy.......To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17ß-estradiol vaginal tablets in postmenopausal women with vaginal atrophy....

  9. Endometrial safety of ultra-low-dose estradiol vaginal tablets

    DEFF Research Database (Denmark)

    Simon, James; Nachtigall, Lila; Ulrich, Lian G

    2010-01-01

    To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17β-estradiol vaginal tablets in postmenopausal women with vaginal atrophy.......To evaluate the endometrial hyperplasia and carcinoma rate after 52-week treatment with ultra-low-dose 10-microgram 17β-estradiol vaginal tablets in postmenopausal women with vaginal atrophy....

  10. Study of genomic instability induced by low dose ionizing radiation

    International Nuclear Information System (INIS)

    Seoane, A.; Crudeli, C.; Dulout, F.

    2006-01-01

    The crews of commercial flights and services staff of radiology and radiotherapy from hospitals are exposed to low doses of ionizing radiation. Genomic instability includes those adverse effects observed in cells, several generations after the exposure occurred. The purpose of this study was to analyze the occurrence of genomic instability by very low doses of ionizing radiation [es

  11. Comparision the value of detecting myocardial viability between low dose dobutamine stress MRI and echocardiography

    International Nuclear Information System (INIS)

    He Yi; Zhang Zhaoqi; Yu Wei; Miao Cuilian; Zhao Yike; Yan Zixu

    2006-01-01

    Objective: To Compare the diagnostic value between low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI in detecting myocardial viability of chronic myocardial infarction. Methods: Rest and low dose dobutamine (5, 10 μg·kg -1 ·min -1 ) stress transthrotic echocardiography and cine-MRI were performed in 30 patients with chronic myocardial infarction. 24 patients underwent successful revascularization and 10 of them underwent another rest cine-MRI study to assess segmental myocardial functional recovery. Left ventricular were divided into 16 segments, the criteria of viability in different techniques is: MRI: dobutamine induced systolic wall thickening was ≥2 mm in akinetic or diskinetic segments at rest; Echocardiography: wall motion score reduced at least 1 after dobutamine stress in akinetic or' diskinetic segments at rest. Results: One hundren and eight segments showed wall motion abnormalities of 30 patients, 65 and 56 segments shows positive reaction, 43 and 52 segments shows negativereaction in MRI and echocardiography after dobutamine stress respectively. Kappa value of the two techniques is 0.75, concordance in both techniques is 88%. Twenty-four segments showed functional recovery, 14 segments remained dysfunction 3-6 months after revascularization, the sensitivity, specificity and accuracy of detecting myocardial viability in chronic myocardial infarction in MRI and echocardiography is 95.8% vs 79.2% (P>0.05), 85.7% vs 85.7% (P>0.05), 92.1% vs 81.6% (P>0.05) respectively. The sensitivity and accuracy of MRI is a little higher. Conclusion: The ability of detecting myocardial viability by both low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI is similer, the sensitivity and accuracy of MRI is a little higher. (authors)

  12. A single low dose of Fe ions can cause long-term biological responses in NL20 human bronchial epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Qianlin; Wang, Jingdong; Cao, Jianping; Yang, Hongying [Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, School of Radiation Medicine and Protection, Suzhou, Jiangsu (China); Liu, Wei [Soochow University, Department of Radiotherapy and Oncology, Second Affiliated Hospital, Suzhou, Jiangsu (China)

    2018-03-15

    Space radiation cancer risk may be a potential obstacle for long-duration spaceflight. Among all types of cancer space radiation may induce, lung cancer has been estimated to be the largest potential risk. Although previous animal study has shown that Fe ions, the most important contributor to the total dose equivalent of space radiation, induced a higher incidence of lung tumorigenesis per dose than X-rays, the underlying mechanisms at cellular level remained unclear. Therefore, in the present study, we investigated long-term biological changes in NL20 human bronchial epithelial cells after exposure to Fe ion or X-ray irradiation. We found that compared with sham control, the progeny of NL20 cells irradiated with 0.1 Gy of Fe ions showed slightly increased micronucleus formation, significantly decreased cell proliferation, disturbed cell cycle distribution, and obviously elevated intracellular ROS levels accompanied by reduced SOD1 and SOD2 expression, but the progeny of NL20 cells irradiated with 0.9 Gy of X-rays did not show any significant changes. More importantly, Fe ion exposure caused much greater soft-agar colony formation than X-rays did in the progeny of irradiated NL20 cells, clearly suggesting higher cell transformation potential of Fe ions compared with X-rays. These data may shed the light on the potential lung tumorigenesis risk from Fe ion exposure. In addition, ATM inhibition by Ku55933 reversed some of the changes in the progeny of Fe ion-irradiated cells but not others such as soft-agar colony formation, suggesting complex processes from DNA damage to carcinogenesis. These data indicate that even a single low dose of Fe ions can induce long-term biological responses such as cell transformation, etc., suggesting unignorable health risk from space radiation to astronauts. (orig.)

  13. Risk at Low Doses: Scientific knowledge, uncertainties and management

    International Nuclear Information System (INIS)

    Giusssani, A.; Ballarini, F.; Ottolenghi, A.

    2002-01-01

    Most of the applications of ionizing radiation in the medical field, for the exposed workers as well as the majority of patients undergoing diagnostic examinations, can be seen as low situations. Epidemiological information is however available for dose and dose rates higher than the values typical of most medical situation. Main source of information is the Life Span Study (LSS) of Japanese. A-bomb survivors, supplemented by studies of selected groups of exposed workers (uranium miners, radium painters) or radiotherapy patients with a detailed follow-up history. All of these group studies, however, suffer from one or more of the following limitations: - lack of adequate dosimetry - lack of a reliable control group for the necessary comparison - influence of concomitant factors (not always easy to find out) - influence of social conditions. In addition exposed study populations are different than the population of patients for which the risk estimates are needed in the medical situation. Recent studies aimed to evaluate the available data on the cohorts of the inhabitants of the Techa river settlements as well as of the workers of the Mayak nuclear facilities may provide in the future useful information on large populations chronically exposed to relatively low doses. (Author)

  14. Biological responses to low dose rate gamma radiation

    International Nuclear Information System (INIS)

    Magae, Junji; Ogata, Hiromitsu

    2003-01-01

    Linear non-threshold (LNT) theory is a basic theory for radioprotection. While LNT dose not consider irradiation time or dose-rate, biological responses to radiation are complex processes dependent on irradiation time as well as total dose. Moreover, experimental and epidemiological studies that can evaluate LNT at low dose/low dose-rate are not sufficiently accumulated. Here we analyzed quantitative relationship among dose, dose-rate and irradiation time using chromosomal breakage and proliferation inhibition of human cells as indicators of biological responses. We also acquired quantitative data at low doses that can evaluate adaptability of LNT with statistically sufficient accuracy. Our results demonstrate that biological responses at low dose-rate are remarkably affected by exposure time, and they are dependent on dose-rate rather than total dose in long-term irradiation. We also found that change of biological responses at low dose was not linearly correlated to dose. These results suggest that it is necessary for us to create a new model which sufficiently includes dose-rate effect and correctly fits of actual experimental and epidemiological results to evaluate risk of radiation at low dose/low dose-rate. (author)

  15. Cancer risk of low dose/low dose rate radiation: a meta-analysis of cancer data of mammals exposed to low doses of radiation

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu; Magae, Junji

    2008-01-01

    Full text: Linear No Threshold (LNT) model is a basic theory for radioprotection, but the adaptability of this hypothesis to biological responses at low doses or at low dose rates is not sufficiently investigated. Simultaneous consideration of the cumulative dose and the dose rate is necessary for evaluating the risk of long-term exposure to ionizing radiation at low dose. This study intends to examine several numerical relationships between doses and dose rates in biological responses to gamma radiation. Collected datasets on the relationship between dose and the incidence of cancer in mammals exposed to low doses of radiation were analysed using meta-regression models and modified exponential (MOE) model, which we previously published, that predicts irradiation time-dependent biological response at low dose rate ionizing radiation. Minimum doses of observable risk and effective doses with a variety of dose rates were calculated using parameters estimated by fitting meta-regression models to the data and compared them with other statistical models that find values corresponding to 'threshold limits'. By fitting a weighted regression model (fixed-effects meta-regression model) to the data on risk of all cancers, it was found that the log relative risk [log(RR)] increased as the total exposure dose increased. The intersection of this regression line with the x-axis denotes the minimum dose of observable risk. These estimated minimum doses and effective doses increased with decrease of dose rate. The goodness of fits of MOE-model depended on cancer types, but the total cancer risk is reduced when dose rates are very low. The results suggest that dose response curve for cancer risk is remarkably affected by dose rate and that dose rate effect changes as a function of dose rate. For scientific discussion on the low dose exposure risk and its uncertainty, the term 'threshold' should be statistically defined, and dose rate effects should be included in the risk

  16. Low dose vitamin C, vitamin E or L-arginine supplementation and ...

    African Journals Online (AJOL)

    The effect of chronic low-dose supplementation with vitamin C (300mg/day for 6 weeks in adults or 100mg/day for 6 weeks in children) or vitamin E (100 IU/day for 6 weeks in adults) or L-Arginine (1g/day for 6 weeks in adults) in ameliorating the pathophysiology and combating the deleterious effects of sickle cell disease in ...

  17. Low-dose Ketamine Versus Morphine for Acute Pain In the ED: A Randomized Controlled Trial

    Science.gov (United States)

    2015-03-01

    pain [18,27,30,31]. Another unique aspect of this study was the use of the RASS score to capture the cognitive and behavioral effects of the study...pregnant or breast-feeding, history of chronic oxygen-dependent pulmonary disease, hepatic cirrhosis, or dialysis dependent, presence of intracranial...studies have evaluated low-dose ketamine as an adjunct to opioid therapy [29,30], as the sole agent without comparison[27], and in a retrospective

  18. On the effect of small radiation doses: Desoxyribonucleic acid (DNA) synthesis and DNA repair of thymus, spleen, and bone marrow cells in the rat after fractionated total body X-ray irradiation. Zur Wirkung kleiner Strahlendosen: Desoxyribonukleinsaeure-(DNA-)Synthese und DNA-Reparatur von Thymus-, Milz- und Knochenmarkszellen der Ratte nach fraktionierter Ganzkoerperroentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Tempel, K.; Ehling, G. (Muenchen Univ. (Germany, F.R.). Inst. fuer Pharmakologie, Toxikologie und Pharmazie)

    1989-09-01

    After three to seven days following to fractionated total body X-ray irradiation (TBI) (four expositions with doses of 0.3 to 5.0 cGy per fraction at intervals of 24 hours), a maximum 50 percent stimulation of the semiconservative DNA synthesis (SDS) of spleen cells was measured in vitro. This was not dependent of the fact if an acute high-dose (400 and/or 800 cGy) unique irradiation was applied after the fractionated TBI at the moment of stimulation. A significant increase of {sup 3}H-thymidine incorporation into the DNA of bone marrow and thymus cells was only found when doses of 1.25 cGy per fraction had been used. After fractionated TBI with doses of {ge}5 cGy per fraction, an increase of DNA synthesis resistant to hydroxyurea ('unprogrammed' DNA synthesis, UDS) was demonstrated in spleen cells. The UV-simulated UDS decreased proportionately. The sedimentation of thymus, spleen, and bone marrow nucleoids in a neutral saccharose gradient gave no evidence of an increased DNA repair capacity after fractionated TBI. Whereas the SDS stimulation by fractionated TBI with small doses can be explained by a modified proliferation behavior of exposed cells, the UDS behavior of spleen cells after considerably higher radiation doses suggests regenerative processes correlated with an increased number of cells resistant to hydroxyurea and cells presenting an UV repair deficiency. These findings can be considered to be a further proof of the assumed immune-stimulating effect of small radiation doses. (orig.).

  19. Detectability of Sungrazing Comet Soft X-ray Irradiance

    Directory of Open Access Journals (Sweden)

    Su Yeon Oh

    2007-12-01

    Full Text Available Originating from the Oort cloud, some comets disappear to impact against the Sun or to split up by strong gravitational force. Then they don't go back to the Oort cloud. They are called sungrazing comets. The comets are detected by sublimation of ices and ejection of gas and dust through solar heat close to the Sun. There exists the charge transfer from heavy ions in the solar wind to neutral atoms in the cometary atmosphere by interaction with the solar wind. Cometary atoms would be excited to high electronic levels and their de-excitation would result in X-ray emission, or it would be scattering of solar X-ray emission by very small cometary grains. We calculated the X-ray emission applying the model suggested by Mendis & Flammer (1984 and Cravens (1997. In our estimation, the sungrazing comet whose nucleus size is about 1 km in radius might be detectable within a distance of 3 solar radius from the sun on soft X-ray solar camera.

  20. Deaths of cancer cells observed after X-Ray irradiation

    International Nuclear Information System (INIS)

    Kuwahara, Yoshikazu; Oikawa, Toshiyuki; Ochiai, Yasushi; Fukumoto, Motoi; Kurihara, Ai; Noma, Naoto; Shimura, Tsutomu; Fukumoto, Manabu; Ohkubo, Yasuhito

    2011-01-01

    Radiation induces cell death by apoptosis, autophagy (autophagic cell death, APCD), necrosis, which are respectively called type I, II, III programmed cell death, senescence, mitotic catastrophe, etc. This paper mainly describes details of authors' studies on APCD of clinically relevant radioresistant (CRR) HepG2-8960-R cells established from proliferating survivor even after repeated X-irradiation of >30 days x 2 Gy/day to the parent HepG2 cells. Autophagy forms autophagosome where many proteins are thoroughly degraded differing from proteasomal ubiquitin system, has been known essentially related to death and survival of injured cells under certain tissue conditions, and is distinguishable from other modes of cell death by morphological and cytochemical means. One of important authors' findings is as follows. APCD of CRR cells is normally seen in 20% and of the parent strain, 5%. When they are X-irradiated at 10 Gy, APCD of the latter is more (70%) than the former (40%), and no APCD is induced by 2 Gy x 5 days in the former in contrast to the latter. APCD by radiation is thus conceivably suppressed in CRR cells, suggesting that their radioresistance can be reversed by treatment to induce APCD. Autophagy is usually suppressed by mammalian target of rapamycin (mTOR), and when CRR cells are treated with rapamycin, they become radiosensitive to the comparable level to the parent HepG2. When HepG2 cells are treated with 3-methyladenine, an inhibitor of autophagy, or Beclin siRNA, they become radioresistant. For effectiveness of APCD induction and suppression on cancer therapy, results are contradictory in certain reports and autophagy should be a problem to be further elucidated from radiation biology aspect. (author)

  1. Discoid lupus erythematosus exacerbated by X-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Eedy, D J; Corbett, J R

    1988-05-01

    The authors describe a patient, previously known to have discoid lupus erythematosus (LE) developing a LE rash in the precise distribution of radiation therapy given for the treatment of a bronchogenic neoplasm.

  2. Discoid lupus erythematosus exacerbated by X-ray irradiation

    International Nuclear Information System (INIS)

    Eedy, D.J.; Corbett, J.R.

    1988-01-01

    The authors describe a patient, previously known to have discoid lupus erythematosus (LE) developing a LE rash in the precise distribution of radiation therapy given for the treatment of a bronchogenic neoplasm. (author)

  3. Effects of soft x-ray irradiation on cell ultrastructure

    International Nuclear Information System (INIS)

    Ford, T.W.; Page, A.M.; Stead, A.D.; Foster, G.F.

    1993-01-01

    The future of X-ray microscopy lies mainly in its potential for imaging fresh, hydrated biological material at a resolution superior to that of light microscopy. For the image to be accepted as representing the cellular organization of the living cell, it is essential that artifacts are not introduced as a result of the image collection system. One possible source of artifacts is cellular damage resulting from the irradiation of the material with soft X-rays. Cells of the unicellular alga Chlorella have been examined by transmission electron microscopy (TEM) following exposure to different doses of monochromatic (380eV) soft X-rays. Extreme ultrastructural damage has been detected following doses of 10 3 -10 4 Gy, in particular loss of cellular membranes such as the internal thylakoid membranes of the chloroplast. This is discussed in relation to dosage commonly used for imaging by soft X-ray microscopy

  4. Risk of cancer subsequent to low-dose radiation

    International Nuclear Information System (INIS)

    Warren, S.

    1980-01-01

    The author puts low dose irradiation risks in perspective using average background radiation doses for standards. He assailed irresponsible media coverage during the height of public interest in the Three-Mile Island Reactor incident

  5. Topics on study of low dose-effect relationship

    International Nuclear Information System (INIS)

    Yamada, Takeshi; Ohyama, Harumi

    1999-01-01

    It is not exceptional but usually observed that a dose-effect relationship in biosystem is not linear. Sometimes, the low dose-effect relationship appears entirely contrary to the expectation from high dose-effect. This is called a 'hormesis' phenomena. A high dose irradiation inflicts certainly an injury on biosystem. No matter how low the dose may be, an irradiation might inflict some injury on biosystem according to Linear Non-Threshold hypothesis(LNT). On the contrary to the expectation, a low dose irradiation stimulates immune system, and promotes cell proliferation. This is called 'radiation hormesis'. The studies of the radiation hormesis are made on from four points of view as follows: (1) radiation adaptive response, (2) revitalization caused by a low dose stimulation, (3) a low dose response unexpected from the LNT hypothesis, (4) negation of the LNT hypothesis. The various empirical proofs of radiation hormesis are introduced in the report. (M . Suetake)

  6. Development of Plant Application Technique of Low Dose Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek (and others)

    2007-07-15

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources.

  7. Low dose rate Ir-192 interstitial brachytherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Oki, Yosuke; Dokiya, Takushi; Yorozu, Atsunori; Suzuki, Takayuki; Saito, Shiro; Monma, Tetsuo; Ohki, Takahiro [National Tokyo Medical Center (Japan); Murai, Masaru; Kubo, Atsushi

    2000-04-01

    From December 1997 through January 1999, fifteen prostatic cancer patients were treated with low dose rate Ir-192 interstitial brachytherapy using TRUS and perineal template guidance without external radiotherapy. Up to now, as no apparent side effects were found, the safety of this treatment is suggested. In the future, in order to treat prostatic cancer patients with interstitial brachytherapy using I-125 or Pd-103, more investigation for this low dose rate Ir-192 interstitial brachytherapy is needed. (author)

  8. Development of Plant Application Technique of Low Dose Radiation

    International Nuclear Information System (INIS)

    Chung, Byung Yeoup; Kim, Jae Sung; Lim, Yong Taek

    2007-07-01

    The project was carried out to achieve three aims. First, development of application techniques of cell-stimulating effects by low-dose radiation. Following irradiation with gamma-rays of low doses, beneficial effects in crop germination, early growth, and yield were investigated using various plant species and experimental approaches. For the actual field application, corroborative studies were also carried out with a few concerned experimental stations and farmers. Moreover, we attempted to establish a new technique of cell cultivation for industrial mass-production of shikonin, a medicinal compound from Lithospermum erythrorhizon and thereby suggested new application fields for application techniques of low-dose radiation. Second, elucidation of action mechanisms of ionizing radiation in plants. By investigating changes in plant photosynthesis and physiological metabolism, we attempted to elucidate physiological activity-stimulating effects of low-dose radiation and to search for radiation-adaptive cellular components. Besides, analyses of biochemical and molecular biological mechanisms for stimulus-stimulating effects of low-dose radiation were accomplished by examining genes and proteins inducible by low-dose radiation. Third, development of functional crop plants using radiation-resistant factors. Changes in stress-tolerance of plants against environmental stress factors such as light, temperature, salinity and UV-B stress after exposed to low-dose gamma-rays were investigated. Concerned reactive oxygen species, antioxidative enzymes, and antioxidants were also analyzed to develop high value-added and environment-friendly functional plants using radiation-resistant factors. These researches are important to elucidate biological activities increased by low-dose radiation and help to provide leading technologies for improvement of domestic productivity in agriculture and development of high value-added genetic resources

  9. Review of European research trends of low dose radiation risk

    International Nuclear Information System (INIS)

    Iwasaki, Toshiyasu; Yoshida, Kazuo

    2010-01-01

    Large research projects on low dose radiation effects in Europe and US over the past decade have provided limited scientific knowledge which could underpin the validation of radiation protection systems. Recently in Europe, there have been repeated discussions and dialogues to improve the situation, and as the consequence, the circumstances surrounding low dose radiation risks are changing. In 2009, Multidisciplinary European Low Dose Initiative (MELODI) was established as a trans-national organization capable of ensuring appropriate governance of research in the pursuit of a long term shared vision, and Low Dose Research towards Multidisciplinary Integration (DoReMi) network was launched in 2010 to achieve fairly short term results in order to prove the validity of the MELODI approach. It is expected to be very effective and powerful activities to facilitate the reduction of uncertainties in the understanding of low dose risks, but the regulatory requests rushing the reinforcement of radiological protection regulations based on the precautional principles are more increasing. To develop reasonable radiological protection systems based on scientific evidences, we need to accelerate to collect scientific evidences which could directly underpin more appropriate radiation protection systems even in Japan. For the purpose, we Japan need to develop from an independent standpoint and share as a multidisciplinary vision a long term and holistic research strategy which enables to enhance Japanese advantages such as low dose rate facilities and animal facilities, as soon as possible. (author)

  10. Life span and tumorigenesis in mice exposed to continuous low dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Tanaka, Satoshi; Braga-Tanaka III, Ignacia; Takabatake, Takashi; Ichinohe, Kazuaki; Tanaka, Kimio; Matsumoto, Tsuneya; Sato, Fumiaki

    2004-01-01

    Two experiments were conducted to evaluate late biological effects of chronic low dose-rate radiation. 1: Late effects of chronic low dose-rate gamma-ray irradiation on SPF mice, using life span and pathological changes as parameters. Continuous irradiation for approximately 400 days was performed using 137 Cs gamma-rays at dose-rates of 20 mGy/day, 1 mGy/day and 0.05 mGy/day with accumulated doses equivalent to 8000 mGy, 400 mGy and 20 mGy, respectively. All mice were kept until their natural death. Statistical analyses show that the life spans of the both sexes irradiated at 20 mGy/day (p<0.0001) and of females irradiated at 1 mGy/day (p<0.05) were significantly shorter than those of the control group. There was no evidence of lengthened life span in mice continuously exposed to very low dose-rates of gama-rays. Pathodological examinations showed that the most frequently observed lethal neoplasms in males were malignant lymphomas, liver, lung, and soft tissue neoplasms, whereas, in females, malignant lymphomas and soft tissue neoplasms were common. No significant difference in the causes of death and mortality rates between groups. Hematopoietic neoplasms (malignant lymphoma and myeloid leukemia), liver, lung and soft tissue neoplasms, showed a tendency to appear at a younger age in both sexes irradiated at 20 mGy/day. Experiment 2: effects on the progeny of chronic low dose-rate gamma-ray irradiated SPF mice: preliminary study. No significant difference was observed between non-irradiated group and irradiated group with regards to litter size, sex ratio and causes of death in F1 and F2 mice. (author)

  11. Ameliorative effects of low dose/low dose-rate irradiation on reactive oxygen species-related diseases model mice

    International Nuclear Information System (INIS)

    Nomura, Takaharu

    2008-01-01

    Living organisms have developed complex biological system which protects themselves against environmental radiation, and irradiation with proper dose, dose-rate and irradiation time can stimulate their biological responses against oxidative stress evoked by the irradiation. Because reactive oxygen species are involved in various human diseases, non-toxic low dose/low dose-rate radiation can be utilized for the amelioration of such diseases. In this study, we used mouse experimental models for fatty liver, nephritis, diabetes, and ageing to elucidate the ameliorative effect of low dose/low dose-rate radiation in relation to endogenous antioxidant activity. Single irradiation at 0.5 Gy ameliorates carbon tetrachloride-induced fatty liver. The irradiation increases hepatic anti-oxidative system involving glutathione and glutathione peroxidase, suggesting that endogenous radical scavenger is essential for the ameliorative effect of low dose radiation on carbon tetrachloride-induced fatty liver. Single irradiation at 0.5 Gy ameliorates ferric nitrilotriacetate-induced nephritis. The irradiation increases catalase and decreases superoxide dismutase in kidney. The result suggests that low dose radiation reduced generation of hydroxide radical generation by reducing cellular hydroperoxide level. Single irradiation at 0.5 Gy at 12 week of age ameliorates incidence of type I diabetes in non-obese diabetic (NOD) mice through the suppression of inflammatory activity of splenocytes, and resultant apoptosis of β-cells in pancreas. The irradiation activities of superoxide dismutase and catalase, which coordinately diminish intracellular reactive oxygen species. Continuous irradiation at 0.70 mGy/hr from 10 week of age elongates life span, and suppresses alopecia in type II diabetesmice. The irradiation improved glucose clearance without affecting insulin-resistance, and increased pancreatic catalase activity. The results suggest that continuous low dose-rate irradiation protect

  12. Low Dose Suppression of Neoplastic Transformation in Vitro

    Energy Technology Data Exchange (ETDEWEB)

    John Leslie Redpath

    2012-05-01

    This grant was to study the low dose suppression of neoplastic transformation in vitro and the shape of the dose-response curve at low doses and dose-rates of ionizing radiation. Previous findings had indicated a suppression of transformation at dose <10cGy of low-LET radiation when delivered at high dose-rate. The present study indicates that such suppression extends out to doses in excess of 100cGy when the dose (from I-125 photons) is delivered at dose-rates as low as 0.2 mGy/min and out to in excess of {approx}25cGy the highest dose studied at the very low dose-rate of 0.5 mGy/day. We also examined dose-rate effects for high energy protons (which are a low-LET radiation) and suppression was evident below {approx}10cGy for high dose-rate delivery and at least out to 50cGy for low dose-rate (20cGy/h) delivery. Finally, we also examined the effect of low doses of 1 GeV/n iron ions (a high-LET radiation) delivered at high dose-rate on transformation at low doses and found a suppression below {approx}10cGy that could be attributable to an adaptive response in bystander cells induced by the associated low-LET delta rays. These results have implications for cancer risk assessment at low doses.

  13. Exposure of luminous marine bacteria to low-dose gamma-radiation.

    Science.gov (United States)

    Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

    2017-04-01

    The study addresses biological effects of low-dose gamma-radiation. Radioactive 137 Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity

    International Nuclear Information System (INIS)

    Kudryasheva, N.S.; Rozhko, T.V.

    2015-01-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1 – absence of effects (stress recognition), 2 – activation (adaptive response), and 3 – inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. - Highlights: • Luminous bacteria demonstrate nonlinear dose-effect relation in radioactive solutions. • Response to low-dose radiation includes 3 stages: threshold, activation, inhibition. • ROS are responsible for low-dose effects of alpha-emitting radionuclides. • Luminous marine bacteria are a convenient tool to study radiation hormesis

  15. Effects of low dose radiation on tumor-bearing mice

    International Nuclear Information System (INIS)

    Feng Li; Hou Dianjun; Huang Shanying; Deng Daping; Wang Linchao; Cheng Yufeng

    2007-01-01

    Objective: To explore the effects of low-dose radiation on tumor-bearing mice and radiotherapy induced by low-dose radiation. Methods: Male Wistar mice were implanted with Walker-256 sarcoma cells in the right armpit. On day 4, the mice were given 75 mGy whole-body X-ray radiation. From the fifth day, tumor volume was measured, allowing for the creation of a graph depicting tumor growth. Lymphocytes activity in mice after whole-body X-ray radiation with LDR was determinned by FCM. Cytokines level were also determined by ELISA. Results: Compared with the radiotherapy group, tumor growth was significantly slower in the mice pre-exposed to low-dose radiation (P<0.05), after 15 days, the average tumor weight in the mice pre- exposed to low-dose radiation was also significantly lower (P<0.05). Lymphocytes activity and the expression of the CK in mice after whole-body y-ray radiation with LDR increased significantly. Conclusions: Low-dose radiation can markedly improve the immune function of the lymphocyte, inhibit the tumor growth, increase the resistant of the high-dose radiotherapy and enhance the effect of radiotherapy. (authors)

  16. Low Dose Vaporized Cannabis Significantly Improves Neuropathic Pain

    Science.gov (United States)

    Wilsey, Barth; Marcotte, Thomas D.; Deutsch, Reena; Gouaux, Ben; Sakai, Staci; Donaghe, Haylee

    2013-01-01

    We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling either medium dose (3.53%), low dose (1.29%), or placebo cannabis with the primary outcome being VAS pain intensity. Psychoactive side-effects, and neuropsychological performance were also evaluated. Mixed effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the two active dose groups’ results (p>0.7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo vs. low dose, 2.9 for placebo vs. medium dose, and 25 for medium vs. low dose. As these NNT are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being, for all intents and purposes, as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well-tolerated, and neuropsychological effects were of limited duration and readily reversible within 1–2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. PMID:23237736

  17. Risks to health from radiation at low dose rates

    International Nuclear Information System (INIS)

    Gentner, N.E.; Osborne, R.V.

    1997-01-01

    Our focus is on whether, using a balance-of-evidence approach, it is possible to say that at a low enough dose, or at a sufficiently low dose rate, radiation risk reduces to zero in a population. We conclude that insufficient evidence exists at present to support such a conclusion. In part this reflects statistical limitations at low doses, and in part (although mechanisms unquestionably exist to protect us against much of the damage induced by ionizing radiation) the biological heterogeneity of human populations, which means these mechanisms do not act in all members of the population at all times. If it is going to be possible to demonstrate that low doses are less dangerous than we presently assume, the evidence, paradoxically, will likely come from studies of higher dose and dose rate scenarios than are encountered occupationally. (author)

  18. Biological effects of low-dose ionizing radiation exposure

    International Nuclear Information System (INIS)

    Reinoehl-Kompa, Sabine; Baldauf, Daniela; Heller, Horst

    2009-01-01

    The report on the meeting of the Strahlenschutzkommission 2007 concerning biological effects of low-dose ionizing radiation exposure includes the following contributions: Adaptive response. The importance of DNA damage mechanisms for the biological efficiency of low-energy photons. Radiation effects in mammography: the relative biological radiation effects of low-energy photons. Radiation-induced cataracts. Carcinomas following prenatal radiation exposure. Intercellular apoptosis induction and low-dose irradiation: possible consequences for the oncogenesis control. Mechanistic models for the carcinogenesis with radiation-induced cell inactivation: application to all solid tumors in the Japanese atomic bomb survivors. Microarrays at low radiation doses. Mouse models for the analysis of biological effects of low-dose ionizing radiation. The bystander effect: observations, mechanisms and implications. Lung carcinoma risk of Majak workers - modeling of carcinogenesis and the bystander effect. Microbeam studies in radiation biology - an overview. Carcinogenesis models with radiation-induced genomic instability. Application to two epidemiological cohorts.

  19. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, Suthakar, E-mail: s.ganapathy@neu.edu [Center for Drug Development, Northeastern University, Boston (United States); Li, Ping [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Fagman, Johan [The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden); Yu, Tianqi; Lafontant, Jean [Center for Drug Development, Northeastern University, Boston (United States); Zhang, Guojun [The First Affiliated Hospital, Zhengzhou University, Zhengzhou (China); Chen, Changyan [Center for Drug Development, Northeastern University, Boston (United States); The Institute of Clinic Sciences, Sahlgrenska Academy, Gothenburg (Sweden)

    2016-09-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  20. Low doses of arsenic, via perturbing p53, promotes tumorigenesis

    International Nuclear Information System (INIS)

    Ganapathy, Suthakar; Li, Ping; Fagman, Johan; Yu, Tianqi; Lafontant, Jean; Zhang, Guojun; Chen, Changyan

    2016-01-01

    In drinking water and in workplace or living environments, low doses of arsenic can exist and operate as a potent carcinogen. Due to insufficient understanding and information on the pervasiveness of environmental exposures to arsenic, there is an urgent need to elucidate the underlying molecular mechanisms of arsenic regarding its carcinogenic effect on human health. In this study, we demonstrate that low doses of arsenic exposure mitigate or mask p53 function and further perturb intracellular redox state, which triggers persistent endoplasmic reticulum (ER) stress and activates UPR (unfolded protein response), leading to transformation or tumorigenesis. Thus, the results suggest that low doses of arsenic exposure, through attenuating p53-regulated tumor suppressive function, change the state of intracellular redox and create a microenvironment for tumorigenesis. Our study also provides the information for designing more effective strategies to prevent or treat human cancers initiated by arsenic exposure.

  1. Regulatory aspects of low doses control in Albania

    International Nuclear Information System (INIS)

    Dollani, K.; Kushe, R.

    1997-01-01

    In the present paper are described the status of regulatory aspects of low doses control as well as the existing procedures for their implementation in Albania. According to new Radiological Protection Act, approved by Parliament in 1995, the establishment of the infrastructures in radiation protection area is in course, accompanied by the installation and functioning of new equipment for low dose control. Based in many years experience it is concluded that personal doses of the workers added by practices in Albania are 1/10 of dose Emits. Some particular cases of overexposured workers were investigated. Last times the elements of the optimisation procedures (QA and QC) are outlined in the frame of improving regulatory aspects of low doses control. (author)

  2. Low-Dose Risk, Decisions, and Risk Communication

    International Nuclear Information System (INIS)

    Flynn, James; Slovic, Paul

    2001-01-01

    To conduct basic research on how people receive, evaluate, and form positions on scientific information and its relationship to low-dose radiation exposure. There are three major areas of study in our research program. First is the development of theories, frameworks and concepts essential to guiding data collection and analysis. The second area is a program of experimental studies on risk perception, evaluation of science information, and the structure of individual positions regarding low dose exposures. This involves the study of existing knowledge and the evaluation of science information presented within a variety of formats, as educational information, news media stories, and alternative communication methods (personal contact, small group interaction, email and internet, etc.). Third is the community-level studies to examine and record how the social conditions, under which science communications take place, influence the development of attitudes and opinions about: low- dose exposures, the available management options, control of radiation risks, and preferences for program and policy goals

  3. Effects of low dose radiation and epigenetic regulation

    International Nuclear Information System (INIS)

    Jiao Benzheng; Ma Shumei; Yi Heqing; Kong Dejuan; Zhao Guangtong; Gao Lin; Liu Xiaodong

    2010-01-01

    Purpose: To conclude the relationship between epigenetics regulation and radiation responses, especially in low-dose area. Methods: The literature was examined for papers related to the topics of DNA methylation, histone modifications, chromatin remodeling and non-coding RNA modulation in low-dose radiation responses. Results: DNA methylation and radiation can regulate reciprocally, especially in low-dose radiation responses. The relationship between histone methylation and radiation mainly exists in the high-dose radiation area; histone deacetylase (HDAC) inhibitors show a promising application to enhance radiation sensitivity, no matter whether in low-dose or high-dose areas; the connection between γ-H2AX and LDR has been remained unknown, although γ-H2AX has been shown no radiation sensitivities with 1-15 Gy irradiation; histone ubiquitination play an important role in DNA damage repair mechanism. Moreover, chromatin remodeling has an integral role in DSB repair and the chromatin response, in general, may be precede DNA end resection. Finally, the effect of radiation on miRNA expression seems to vary according to cell type, radiation dose, and post-irradiation time point. Conclusion: Although the advance of epigenetic regulation on radiation responses, which we are managing to elucidate in this review, has been concluded, there are many questions and blind blots deserved to investigated, especially in low-dose radiation area. However, as progress on epigenetics, we believe that many new elements will be identified in the low-dose radiation responses which may put new sights into the mechanisms of radiation responses and radiotherapy. (authors)

  4. Low-dose vaporized cannabis significantly improves neuropathic pain.

    Science.gov (United States)

    Wilsey, Barth; Marcotte, Thomas; Deutsch, Reena; Gouaux, Ben; Sakai, Staci; Donaghe, Haylee

    2013-02-01

    We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling medium-dose (3.53%), low-dose (1.29%), or placebo cannabis with the primary outcome being visual analog scale pain intensity. Psychoactive side effects and neuropsychological performance were also evaluated. Mixed-effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the 2 active dose groups' results (P > .7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo versus low-dose, 2.9 for placebo versus medium-dose, and 25 for medium- versus low-dose. As these NNTs are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well tolerated, and neuropsychological effects were of limited duration and readily reversible within 1 to 2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. The analgesia obtained from a low dose of delta-9-tetrahydrocannabinol (1.29%) in patients, most of whom were experiencing neuropathic pain despite conventional treatments, is a clinically significant outcome. In general, the effect sizes on cognitive testing were consistent with this minimal dose. As a result, one might not anticipate a significant impact on daily functioning. Published by Elsevier Inc.

  5. The researches on the effects of low doses irradiation

    International Nuclear Information System (INIS)

    2009-02-01

    All research conducted as part of 'Risc-Rad' and those conducted by actors in international programs on low doses allow progress in understanding mechanisms of carcinogenesis associated with irradiation. The data do not question the use in radiation protection, risk estimation models based on a linear increase of the risk with the dose of radiation. Nevertheless, they show that the nature of biological responses induced by low doses of radiation has differences with the responses induced by high doses of radiation. They also show the diversity of effects/dose relationships as the mechanism observed and the importance of genetic predisposition in the individual sensitivity to low doses of radiation. It is therefore essential to continue to bring new data to better understand the complex biological effects and their impact on the establishment of radiation protection standards. In addition, the results have often been at the cellular level. The diversity of responses induced by radiations is also a function of cell types observed, the aging of cells and tissue organization. It is essential to strengthen researches at the tissue and body level, involving in vitro and in vivo approaches while testing the hypothesis in epidemiology with a global approach to systems biology. Over the past four years, the collaboration between partners of 'Risc-Rad' using experimental biology approaches and those using mathematical modeling techniques aimed at developing a new model describing the carcinogenesis induced by low radiation doses. On an other hand, The High level expert group on European low dose risk research (H.L.E.G.) develop programmes in the area of low dose irradiation (Germany, Finland, France, Italy and United Kingdom). It proposed a structure of trans national government called M.E.L.O.D.I. ( multidisciplinary european low dose initiative). Its objective is to structure and integrate European research by gathering around a common programme of multidisciplinary

  6. Some remarks on the significance of low doses

    International Nuclear Information System (INIS)

    Cigna, A.A.

    1989-12-01

    The criteria of the present system of individual dose limitation are considered as well as the evolution of the limiting values. The assumption of the linearity of the dose-effect relationship without any threshold is probably the best approach to adopt for recommendations in radiation protection and for accounting the doses acquired by exposure to ionizing radiation. On the other hand the present evaluation of the natural background could imply a different dose-effect relationship in the low doses region and perhaps the existence of a threshold. Therefore the extrapolations which are usually made after exposures of different groups of people to low doses cannot be considered as scientifically sound. (author)

  7. Immunomodulatory Effects of Macrolide Antibiotics - Part 2 : Advantages and Disadvantages of Long-Term, Low-Dose Macrolide Therapy

    NARCIS (Netherlands)

    Altenburg, J.; de Graaff, C. S.; van der Werf, T. S.; Boersma, W. G.

    2011-01-01

    The available evidence for long-term, low-dose treatment with 14- and 15-membered ring macrolides in non-cystic fibrosis (CF) bronchiectasis, COPD, chronic sinusitis, and asthma is reviewed with special attention to possible adverse effects and the emergence of resistance during long-term macrolide

  8. Pre-irradiation at a low dose-rate blunted p53 response

    International Nuclear Information System (INIS)

    Takahashi, A.; Ohnishi, K.; Asakawa, I.; Tamamoto, T.; Yasumoto, J.; Yuki, K.; Ohnishi, T.; Tachibana, A.

    2003-01-01

    Full text: We have studied whether the p53-centered signal transduction pathway induced by acute radiation is interfered with chronic pre-irradiation at a low dose-rate in human cultured cells and whole body of mice. In squamous cell carcinoma cells, we found that a challenge irradiation with X-ray immediately after chronic irradiation resulted in lower levels of p53 than those observed after the challenge irradiation alone. In addition, the induction of p53-centered apoptosis and the accumulation of its related proteins after the challenge irradiation were strongly correlated with the above-mentioned phenomena. In mouse spleen, the induction of apoptosis and the accumulation of p53 and Bax were observed dose-dependently at 12 h after a challenge irradiation. In contrast, we found significant suppression of them induced by challenge irradiation at a high dose-rate when mice were pre-irradiated with chronic irradiation at a low dose-rate. These findings suggest that chronic pre-irradiation suppressed the p53 function through radiation-induced p53-dependent signal transduction processes. There are numerous papers about p53 functions in apoptosis, radiosensitivity, genomic instability and cancer incidence in cultured cells or animals. According to our data and other findings, since p53 can prevent carcinogenesis, pre-irradiation at a low dose-rate might enhance the predisposition to cancer. Therefore, it is possible that different maximal permissible dose equivalents for the public populations are appropriate. Furthermore, concerning health of human beings, studies of the adaptive responses to radiation are quite important, because the radiation response strongly depends on experience of prior exposure to radiation

  9. Low-dose memantine attenuated morphine addictive behavior through its anti-inflammation and neurotrophic effects in rats.

    Science.gov (United States)

    Chen, Shiou-Lan; Tao, Pao-Luh; Chu, Chun-Hsien; Chen, Shih-Heng; Wu, Hsiang-En; Tseng, Leon F; Hong, Jau-Shyong; Lu, Ru-Band

    2012-06-01

    Opioid abuse and dependency are international problems. Studies have shown that neuronal inflammation and degeneration might be related to the development of opioid addiction. Thus, using neuroprotective agents might be beneficial for treating opioid addiction. Memantine, an Alzheimer's disease medication, has neuroprotective effects in vitro and in vivo. In this study, we evaluated whether a low dose of memantine prevents opioid-induced drug-seeking behavior in rats and analyzed its mechanism. A conditioned-place-preference test was used to investigate the morphine-induced drug-seeking behaviors in rats. We found that a low-dose (0.2-1 mg/kg) of subcutaneous memantine significantly attenuated the chronic morphine-induced place-preference in rats. To clarify the effects of chronic morphine and low-dose memantine, serum and brain levels of cytokines and brain-derived neurotrophic factor (BDNF) were measured. After 6 days of morphine treatment, cytokine (IL-1β, IL-6) levels had significantly increased in serum; IL-1β and IL-6 mRNA levels had significantly increased in the nucleus accumbens and medial prefrontal cortex, both addiction-related brain areas; and BDNF levels had significantly decreased, both in serum and in addiction-related brain areas. Pretreatment with low-dose memantine significantly attenuated chronic morphine-induced increases in serum and brain cytokines. Low-dose memantine also significantly potentiated serum and brain BDNF levels. We hypothesize that neuronal inflammation and BDNF downregulation are related to the progression of opioid addiction. We hypothesize that the mechanism low-dose memantine uses to attenuate morphine-induced addiction behavior is its anti-inflammatory and neurotrophic effects.

  10. Health effects of low doses at low dose rates: dose-response relationship modeling in a cohort of workers of the nuclear industry

    International Nuclear Information System (INIS)

    Metz-Flamant, Camille

    2011-01-01

    The aim of this thesis is to contribute to a better understanding of the health effects of chronic external low doses of ionising radiation. This work is based on the French cohort of CEA-AREVA NC nuclear workers. The mains stages of this thesis were (1) conducting a review of epidemiological studies on nuclear workers, (2) completing the database and performing a descriptive analysis of the cohort, (3) quantifying risk by different statistical methods and (4) modelling the exposure-time-risk relationship. The cohort includes monitored workers employed more than one year between 1950 and 1994 at CEA or AREVA NC companies. Individual annual external exposure, history of work, vital status and causes of death were reconstructed for each worker. Standardized mortality ratios using French national mortality rates as external reference were computed. Exposure-risk analysis was conducted in the cohort using the linear excess relative risk model, based on both Poisson regression and Cox model. Time dependent modifying factors were investigated by adding an interaction term in the model or by using exposure time windows. The cohort includes 36, 769 workers, followed-up until age 60 in average. During the 1968- 2004 period, 5, 443 deaths, 2, 213 cancers, 62 leukemia and 1, 314 cardiovascular diseases were recorded. Among the 57% exposed workers, the mean cumulative dose was 21.5 milli-sieverts (mSv). A strong Healthy Worker Effect is observed in the cohort. Significant elevated risks of pleura cancer and melanoma deaths were observed in the cohort but not associated with dose. No significant association was observed with solid cancers, lung cancer and cardiovascular diseases. A significant dose-response relationship was observed for leukemia excluding chronic lymphatic leukemia, mainly for doses received less than 15 years before and for yearly dose rates higher than 10 mSv. This PhD work contributes to the evaluation of risks associated to chronic external radiation

  11. Late effects of low-dose ionizing radiation on man

    International Nuclear Information System (INIS)

    Brilliant, M.D.; Vorob'ev, A.I.; Gogin, E.E.

    1987-01-01

    One of the most important problems, being stated before the medicine by the accident, which took place in Chernobyl in 1986- the problem of the so-called ionizing radiation low dose effect on a man's organism, is considered because a lot of people were subjected to low dose action. The concept of low doses of radiaion action and specificity of its immediate action in comparison with high dose action is considered. One of the most important poit while studying low dose action is the necessity to develop a system including all irradiated people and dosimetry, and espicially to study frequencies and periods of tumor appearance in different irradiated tissues. The results obtained when examining people who survived the atomic explosion in Japan and on the Marshall islands are analyzed. They testify to the fact that radiation affets more tissues than the clinical picture about the acute radiation sickness tells, and that tumors developing in them many years after radiation action tell about radiosensitivity in some tissues

  12. Use of combined paracetamol and low dose ketamine in pain ...

    African Journals Online (AJOL)

    Objective: To determine the effectiveness of Paracetamol and low dose Ketamine in controlling burn pain during dressings. Setting: The burns ward of Moi Teaching and Referral Hospital, a 750 bed capacity tertiary centre in Western Kenya. Subjects: Consenting patients were recruited to the study on admission. Babies and ...

  13. Low-dose aspirin and risk of intracranial bleeds

    DEFF Research Database (Denmark)

    Cea Soriano, Lucía; Gaist, David; Soriano-Gabarró, Montse

    2017-01-01

    cohort of nonusers of low-dose aspirin at baseline were followed (maximum 14 years, median 5.4 years) to identify incident cases of ICB, with validation by manual review of patient records or linkage to hospitalization data. Using 10,000 frequency-matched controls, adjusted rate ratios (RRs) with 95...

  14. Biological effects of very low doses of ionizing radiation

    International Nuclear Information System (INIS)

    Evseev, V.S.

    1987-01-01

    The paper deals with a qualitative microdosimetric analysis of a new radiobiological phenomenon (physiological reaction of the cell as a whole to very low doses of ionizing radiations). The analysis is aimed at identifying the type of the primary interaction of radiation with the cell and finding its place in the cell

  15. Advance of study on hormesis of low dose radiation

    International Nuclear Information System (INIS)

    Su Liaoyuan

    2003-01-01

    There have been growing interests in recent years over the effects of low doses of ionizing radiation on human. The paper gives a brief review on the LDR studies, which include LDR-induced hormesis and adaptive response, LDR experiments in vivo or in vitro and epidemiologic investigation, and clinical applications of LDR as well

  16. Low dose CT simulation using experimental noise model

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Satori; Zamyatin, Alexander A. [Toshiba Medical Systems Corporation, Tochigi, Otawarashi (Japan); Silver, Michael D. [Toshiba Medical Research Institute, Vernon Hills, IL (United States)

    2011-07-01

    We suggest a method to obtain system noise model experimentally without relying on assumptions on statistical distribution of the noise; also, knowledge of DAS gain and electronic noise level are not required. Evaluation with ultra-low dose CT data (5 mAs) shows good match between simulated and real data noise. (orig.)

  17. CARCINOGENIC EFFECTS OF LOW DOSES OF IONIZING RADIATION

    Science.gov (United States)

    Carcinogenic Effects of Low Doses of Ionizing RadiationR Julian Preston, Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711The form of the dose-response curve for radiation-induced cancers, particu...

  18. Malignant melanoma of the tongue following low-dose radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-03-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented.

  19. Malignant melanoma of the tongue following low-dose radiation

    International Nuclear Information System (INIS)

    Kalemeris, G.C.; Rosenfeld, L.; Gray, G.F. Jr.; Glick, A.D.

    1985-01-01

    A 47-year-old man had a spindly malignant melanoma of the tongue many years after low-dose radiation therapy for lichen planus. To our knowledge, only 12 melanomas of the tongue have been reported previously, and in none of these was radiation documented

  20. Topics on study of low dose-effect relationship

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Takeshi [Toho Univ., School of Medicine, Tokyo (Japan); Ohyama, Harumi

    1999-09-01

    It is not exceptional but usually observed that a dose-effect relationship in biosystem is not linear. Sometimes, the low dose-effect relationship appears entirely contrary to the expectation from high dose-effect. This is called a 'hormesis' phenomena. A high dose irradiation inflicts certainly an injury on biosystem. No matter how low the dose may be, an irradiation might inflict some injury on biosystem according to Linear Non-Threshold hypothesis(LNT). On the contrary to the expectation, a low dose irradiation stimulates immune system, and promotes cell proliferation. This is called 'radiation hormesis'. The studies of the radiation hormesis are made on from four points of view as follows: (1) radiation adaptive response, (2) revitalization caused by a low dose stimulation, (3) a low dose response unexpected from the LNT hypothesis, (4) negation of the LNT hypothesis. The various empirical proofs of radiation hormesis are introduced in the report. (M . Suetake)

  1. Health hazards of low doses of ionizing radiations. Vo. 1

    International Nuclear Information System (INIS)

    El-Naggar, M.A.

    1996-01-01

    Exposure to high doses of ionizing radiation results in clinical manifestations of several disease entities that may be fatal. The onset and severity of these acute radiation syndromes are deterministic in relation to dose magnitude. Exposure to ionizing radiations at low doses and low dose rates could initiate certain damage in critical molecules of the cell, that may develop in time into serious health effects. The incidence of such delayed effects in low, and is only detectable through sophisticated epidemiological models carried out on large populations. The radiation damage induced in critical molecules of cells may develop by stochastic biochemical mechanisms of repair, residual damage, adaptive response, cellular transformation, promotion and progression into delayed health effects, the most important of which is carcinogenesis. The dose response relationship of probabilistic stochastic delayed effects of radiation at low doses and low dose rates, is very complex indeed. The purpose of this review is to provide a comprehensive understanding of the underlying mechanisms, the factors involved, and the uncertainties encountered. Contrary to acute deterministic effects, the occurrence of probabilistic delayed effects of radiation remains to be enigmatic. 7 figs

  2. Mechanisms of Low Dose Radio-Suppression of Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Engelward, Bevin P. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2009-09-16

    The major goal of this project is to contribute toward the elucidation of the impact of long term low dose radiation on genomic stability. We have created and characterized novel technologies for delivering long term low dose radiation to animals, and we have studied genomic stability by applying cutting edge molecular analysis technologies. Remarkably, we have found that a dose rate that is 300X higher than background radiation does not lead to any detectable genomic damage, nor is there any significant change in gene expression for genes pertinent to the DNA damage response. These results point to the critical importance of dose rate, rather than just total dose, when evaluating public health risks and when creating regulatory guidelines. In addition to these studies, we have also further developed a mouse model for quantifying cells that have undergone a large scale DNA sequence rearrangement via homologous recombination, and we have applied these mice in studies of both low dose radiation and space radiation. In addition to more traditional approaches for assessing genomic stability, we have also explored radiation and possible beneficial effects (adaptive response), long term effects (persistent effects) and effects on communication among cells (bystander effects), both in vitro and in vivo. In terms of the adaptive response, we have not observed any significant induction of an adaptive response following long term low dose radiation in vivo, delivered at 300X background. In terms of persistent and bystander effects, we have revealed evidence of a bystander effect in vivo and with researchers at and demonstrated for the first time the molecular mechanism by which cells “remember” radiation exposure. Understanding the underlying molecular mechanisms by which radiation can induce genomic instability is fundamental to our ability to assess the biological impact of low dose radiation. Finally, in a parallel set of studies we have explored the effects of heavy

  3. Randomized phase 2 study of low-dose decitabine vs low-dose azacitidine in lower-risk MDS and MDS/MPN.

    Science.gov (United States)

    Jabbour, Elias; Short, Nicholas J; Montalban-Bravo, Guillermo; Huang, Xuelin; Bueso-Ramos, Carlos; Qiao, Wei; Yang, Hui; Zhao, Chong; Kadia, Tapan; Borthakur, Gautam; Pemmaraju, Naveen; Sasaki, Koji; Estrov, Zeev; Cortes, Jorge; Ravandi, Farhad; Alvarado, Yesid; Komrokji, Rami; Sekeres, Mikkael A; Steensma, David P; DeZern, Amy; Roboz, Gail; Kantarjian, Hagop; Garcia-Manero, Guillermo

    2017-09-28

    Hypomethylating agents (HMAs) improve survival in patients with higher-risk myelodysplastic syndromes (MDS) but are less well-studied in lower-risk disease. We compared the safety and efficacy of low-dose decitabine vs low-dose azacitidine in this group of patients. Adults with low- or intermediate 1-risk MDS or MDS/myeloproliferative neoplasm (MPN), including chronic myelomonocytic leukemia, according to the International Prognostic Scoring System, were randomly assigned using a Bayesian adaptive design to receive either azacitidine 75 mg/m 2 intravenously/subcutaneously daily or decitabine 20 mg/m 2 intravenously daily for 3 consecutive days on a 28-day cycle. The primary outcome was overall response rate (ORR). Between November 2012 and February 2016, 113 patients were treated: 40 (35%) with azacitidine and 73 (65%) with decitabine. The median age was 70 years; 81% of patients were intermediate 1-risk patients. The median number of cycles received was 9. The ORRs were 70% and 49% ( P = .03) for patients treated with decitabine and azacitidine, respectively. Thirty-two percent of patients treated with decitabine became transfusion independent compared with 16% of patients treated with azacitidine ( P = .2). Cytogenetic response rates were 61% and 25% ( P = .02), respectively. With a median follow-up of 20 months, the overall median event-free survival was 18 months: 20 and 13 months for patients treated with decitabine and azacitidine, respectively ( P = .1). Treatment was well tolerated, with a 6-week mortality rate of 0%. The use of low-dose HMAs is safe and effective in patients with lower-risk MDS and MDS/MPN. Their effect on the natural history of lower-risk disease needs to be further studied. This trial was registered at clinicaltrials.gov (identifier NCT01720225). © 2017 by The American Society of Hematology.

  4. Personal dosimetry statistics and specifics of low dose evaluation

    International Nuclear Information System (INIS)

    Avila, R.E.; Gómez Salinas, R.A.; Oyarzún Cortés, C.H.

    2015-01-01

    The dose statistics of a personal dosimetry service, considering 35,000+ readings, display a sharp peak at low dose (below 0.5 mSv) with skewness to higher values. A measure of the dispersion is that approximately 65% of the doses fall below the average plus 2 standard deviations, an observation which may prove helpful to radiation protection agencies. Categorizing the doses by the concomitant use of a finger ring dosimeter, that skewness is larger in the whole body, and ring dosimeters. The use of Harshaw 5500 readers at high gain leads to frequent values of the glow curve that are judged to be spurious, i.e. values not belonging to the roughly normal noise over the curve. A statistical criterion is shown for identifying those anomalous values, and replacing them with the local behavior, as fit by a cubic polynomial. As a result, the doses above 0.05 mSv which are affected by more than 2% comprise over 10% of the data base. The low dose peak of the statistics, above, has focused our attention on the evaluation of LiF(Mg,Ti) dosimeters exposed at low dose, and read with Harshaw 5500 readers. The standard linear procedure, via an overall reader calibration factor, is observed to fail at low dose, in detailed calibrations from 0.02 mSv to 1 Sv. A significant improvement is achieved by a piecewise polynomials calibration curve. A cubic, at low dose is matched, at ∼10 mSv, in value and first derivative, to a linear dependence at higher doses. This improvement is particularly noticeable below 2 mSv, where over 60% of the evaluated dosimeters are found. (author)

  5. Detecting airway remodeling in COPD and emphysema using low-dose CT imaging

    Science.gov (United States)

    Rudyanto, R.; Ceresa, M.; Muñoz-Barrutia, A.; Ortiz-de-Solorzano, C.

    2012-03-01

    In this study, we quantitatively characterize lung airway remodeling caused by smoking-related emphysema and Chronic Obstructive Pulmonary Disease (COPD), in low-dose CT scans. To that end, we established three groups of individuals: subjects with COPD (n=35), subjects with emphysema (n=38) and healthy smokers (n=28). All individuals underwent a low-dose CT scan, and the images were analyzed as described next. First the lung airways were segmented using a fast marching method and labeled according to its generation. Along each airway segment, cross-section images were resampled orthogonal to the airway axis. Next 128 rays were cast from the center of the airway lumen in each crosssection slice. Finally, we used an integral-based method, to measure lumen radius, wall thickness, mean wall percentage and mean peak wall attenuation on every cast ray. Our analysis shows that both the mean global wall thickness and the lumen radius of the airways of both COPD and emphysema groups were significantly different from those of the healthy group. In addition, the wall thickness change starts at the 3rd airway generation in the COPD patients compared with emphysema patients, who display the first significant changes starting in the 2nd generation. In conclusion, it is shown that airway remodeling happens in individuals suffering from either COPD or emphysema, with some local difference between both groups, and that we are able to detect and accurately quantify this process using images of low-dose CT scans.

  6. Protective effect of low dose caffeine on psychological stress and cognitive function.

    Science.gov (United States)

    Çakır, Özgür Kasımay; Ellek, Nurfitnat; Salehin, Nabila; Hamamcı, Rabia; Keleş, Hülya; Kayalı, Damla Gökçeoğlu; Akakın, Dilek; Yüksel, Meral; Özbeyli, Dilek

    2017-01-01

    Caffeine is an adrenergic antagonist that enhances neuronal activity. Psychological stress depresses cognitive function. To investigate the effects of acute and chronic low dose caffeine on anxiety-like behavior and cognitive functions of acute or chronic psychological stressed rats. Acute or chronic caffeine (3mg/kg) was administered to male Sprague Dawley rats (200-250g, n=42) before acute (cat odor) and chronic variable psychological stress (restraint overcrowding stress, elevated plus maze, cat odor, forced swimming) induction. Anxiety and cognitive functions were evaluated by hole-board and object recognition tests. The brain glutathione and malondialdehyde assays, myeloperoxidase, nitric oxide (NO), superoxide dismutase (SOD), luminol and lucigenin activity and histological examination were done. ANOVA and Student's t-test were used for statistical analysis. The depressed cognitive function with chronic stress exposure and the increased anxiety-like behavior with both stress inductions were improved via both caffeine applications (pcaffeine pretreatments in chronic stressed rats, and chronic caffeine in acute stressed ones reduced the elevated myeloperoxidase activities (pcaffeine (pcaffeine (pcaffeine decreased SOD activity (pcaffeine. The increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved with both acute and predominantly chronic caffeine pretreatments by decreasing oxidative damage parameters. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Comparison of hyperuricemia in type 2 diabetics on low dose aspirin and not on low dose aspirin

    International Nuclear Information System (INIS)

    Malik, M.I.

    2013-01-01

    Objective: To compare the frequency of hyperuricemia in type 2 diabetes patients who are taking low dose aspirin with those patients who are not taking low dose aspirin. Study design: Quasi experimental study. Place and duration of study: This study was carried out at Military Hospital Rawalpindi for a period of two years (June 2006-May 2008). Patients and Methods: Sixty diabetic patients were selected who were taking low dose aspirin comparing group A and sixty diabetic patients who were not taking aspirin were placed in group B. These patients were selected from the OPD through non probability convenience sampling. All these patients were being followed up in medical outpatient quite regularly on fort-nightly basis. Data had been collected through a carefully designed questionnaire. Results: In group A, 90% of the patients had uric acid less than 445 micro mol/l and 10% of the patients had uric acid more than 445micro mol/l. Whereas in group B 100% of the patients had uric acid less than 445umol/l, there was a statistically significant difference between the two groups (p< 0.05). Conclusion: Aspirin in low doses cause hyperuricemia and regular monitoring of uric acid is mandatory to prevent its adverse effects. (author)

  8. Impacts of low doses of pesticide mixtures on liver cell defence systems

    OpenAIRE

    Zucchini-Pascal, Nathalie; Dupont, Gwendoline; Razpotnik, Andrej; Fouche, Edwin; De Sousa, Georges; Rahmani, Roger

    2012-01-01

    Low amounts of residual pesticides are present in the environment, often as mixtures of chemicals which contaminate drinking water and food, being a source of chronic exposure for humans and a growing matter of concern in public health policy. Despite of the needs and growing investigation, little is known about the impact of low doses and mixtures of these chemicals on human health. The purpose of this study was to enlighten if modifications of liver cell metabolic- and/or defence-related ca...

  9. Evaluation of a combination of low-dose ketamine and low-dose midazolam in terminal dyspnea-attenuation of "double-effect"

    Directory of Open Access Journals (Sweden)

    Abhijit Kanti Dam

    2008-01-01

    Full Text Available Aim: Of all symptoms in palliative medicine those concerning respiration are most excruciating and difficult to treat. Reticence about the use of morphine for palliation of dyspnea is common, especially in nonmalignant diseases, as there is a fear of causing respiratory depression, particularly where Chronic Obstructive Pulmonary Disease (COPD exists. This factor is also compounded by the lack of availability of morphine in parts of developing countries. Ketamine has excellent anesthetic and analgesic effects in addition to being easily available. It produces bronchodilatation and does not produce respiratory or cardiovascular depression. The author seeks to evaluate the role of low-dose (0.2 mg/kg ketamine and midazolam (0.02 mg/kg in the attenuation of terminal dyspnea. Methods: Sixteen patients with terminal dyspnea, admitted to the Critical Care Unit (CCU with cancer and other noncancer diagnoses were recruited. The subjective component of dyspnea was assessed using the Graphic Rating Scale (GRS, which has values from 0 - 10, 10 being maximum dyspnea. Each patient received a low-dose of ketamine and midazolam for relief of dyspnea. All the patients received low-flow (2 L/min. oxygen therapy via nasal cannula. Immediately after admission, all the patients were reassured and nursed in a decubitus position of their choice. The GRS was recorded at the point of admission, 10 minutes after starting oxygen therapy, and ten minutes after administration of low-dose ketamine and midazolam. Hemodynamic parameters were also recorded at these three points. Result: All the patients who enrolled in our study had significant dyspnea at admission, as was evident from the GRS scores of 8.250 (SD 0.91, respiratory rate of 28.56 (SD 5.0, mean arterial blood pressure (MABP of 102.7 (SD 14.63, pulse rate of 115.62 (SD 23.3, and SpO2 of 92.43 (SD 2.38. All the patients benefited from the combination of ketamine and midazolam, as evidenced by the statistically

  10. A Paradigm Shift in Low Dose Radiation Biology

    Directory of Open Access Journals (Sweden)

    Z. Alatas

    2015-08-01

    Full Text Available When ionizing radiation traverses biological material, some energy depositions occur and ionize directly deoxyribonucleic acid (DNA molecules, the critical target. A classical paradigm in radiobiology is that the deposition of energy in the cell nucleus and the resulting damage to DNA are responsible for the detrimental biological effects of radiation. It is presumed that no radiation effect would be expected in cells that receive no direct radiation exposure through nucleus. The risks of exposure to low dose ionizing radiation are estimated by extrapolating from data obtained after exposure to high dose radiation. However, the validity of using this dose-response model is controversial because evidence accumulated over the past decade has indicated that living organisms, including humans, respond differently to low dose radiation than they do to high dose radiation. Moreover, recent experimental evidences from many laboratories reveal the fact that radiation effects also occur in cells that were not exposed to radiation and in the progeny of irradiated cells at delayed times after radiation exposure where cells do not encounter direct DNA damage. Recently, the classical paradigm in radiobiology has been shifted from the nucleus, specifically the DNA, as the principal target for the biological effects of radiation to cells. The universality of target theory has been challenged by phenomena of radiation-induced genomic instability, bystander effect and adaptive response. The new radiation biology paradigm would cover both targeted and non-targeted effects of ionizing radiation. The mechanisms underlying these responses involve biochemical/molecular signals that respond to targeted and non-targeted events. These results brought in understanding that the biological response to low dose radiation at tissue or organism level is a complex process of integrated response of cellular targets as well as extra-cellular factors. Biological understanding of

  11. Addition of low-dose ketamine to midazolam and low-dose bupivacaine improves hemodynamics and postoperative analgesia during spinal anesthesia for cesarean section

    Directory of Open Access Journals (Sweden)

    Ahmed Sobhy Basuni

    2016-01-01

    Conclusion: Intrathecal low-dose ketamine combined with midazolam and low-dose bupivacaine stabilizes hemodynamics and prolongs postoperative analgesia without significant side-effects in parturients undergoing CS.

  12. Repair and dose-response at low doses

    International Nuclear Information System (INIS)

    Totter, J.R.; Weinberg, A.M.

    1977-04-01

    The DNA of each individual is subject to formation of some 2-4 x 10 14 ion pairs during the first 30 years of life from background radiation. If a single hit is sufficient to cause cancer, as is implicit in the linear, no-threshold theories, it is unclear why all individuals do not succumb to cancer, unless repair mechanisms operate to remove the damage. We describe a simple model in which the exposed population displays a distribution of repair thresholds. The dose-response at low dose is shown to depend on the shape of the threshold distribution at low thresholds. If the probability of zero threshold is zero, the response at low dose is quadratic. The model is used to resolve a longstanding discrepancy between observed incidence of leukemia at Nagasaki and the predictions of the usual linear hypothesis

  13. Response of human fibroblasts to low dose rate gamma irradiation

    International Nuclear Information System (INIS)

    Dritschilo, A.; Brennan, T.; Weichselbaum, R.R.; Mossman, K.L.

    1984-01-01

    Cells from 11 human strains, including fibroblasts from patients with the genetic diseases of ataxia telangiectasia (AT), xeroderma pigmentosum (XP), and Fanconi's anemia (FA), were exposed to γ radiation at high (1.6-2.2 Gy/min) and at low (0.03-0.07 Gy/min) dose rates. Survival curves reveal an increase inthe terminal slope (D 0 ) when cells are irradiated at low dose rates compared to high dose rates. This was true for all cell lines tested, although the AT, FA, and XP cells are reported or postulated to have radiation repair deficiencies. From the response of these cells, it is apparent that radiation sensitivities differ; however, at low dose rate, all tested human cells are able to repair injury

  14. Low dose CT in early lung cancer diagnosis: prevalence data

    International Nuclear Information System (INIS)

    Cardinale, Luciano; Cortese, Giancarlo; Ferraris, Fabrizio; Perotto, Fabio; Fava, Cesare; Borasio, Piero; Dogliotti, Luigi; Novello, Silvia; Scagliotti, Giorgio

    2005-01-01

    Purpose. Lung cancer has a high mortality rate and its prognosis largely depends on early detection. We report the prevalence data of the study on early detection of lung cancer with low-dose spiral CT underway at our hospital. Materials and methods. Since the beginning of 2001, 519 asymptomatic volunteers have undergone annual blood tests, sputum tests, urinalyses and low-dose spiral CT. The inclusion criteria were age (55 years old), a history of cigarette smoking and a negative history for previous neoplastic disease. The diagnostic workup varied depending on the size and CT features of the nodules detected. Results. At baseline, the CT scan detected nodules> 5 mm in 22% of subjects; the nodules were single in 42 and multiple in 71. In 53% of cases the findings were completely negative, while in 122 (23.4%) nodules with a diameter [it

  15. Low-Dose Aspirin for the Prevention of Preeclampsia.

    Science.gov (United States)

    Fantasia, Heidi Collins

    2018-02-01

    Preeclampsia is a hypertensive disorder specific to pregnancy that remains a significant cause of maternal and neonatal morbidity and mortality. Identification of women who are most at risk for preeclampsia is imprecise. Because of the potential negative health consequences of preeclampsia for women and newborns and the lack of effective screening mechanisms preventing preeclampsia is an important component of prenatal care. Researchers have documented that low-dose aspirin, taken daily after the first trimester, can decrease the development of preeclampsia and reduce the incidence of preterm birth and birth of small-for-gestational-age infants. This column includes an overview of low-dose aspirin in pregnancy and a review of current recommendations from leading national organizations. © 2018 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses.

  16. The assessment of the carcinogenic effects of low dose radiation

    International Nuclear Information System (INIS)

    Tubiana, M.; Lafuma, J.; Masse, R.; Latarjet, R.

    1991-01-01

    It is concluded that the exclusion of patients for the purposes of risk estimation, the choice of a particular relative risk projection model and of a dose reduction factor equal to 2 are all decisions which result in an overestimation of the actual risk. These choices can be understood when the aim is radiation protection and when it is safer to overestimate the risk; however, they are open to criticism if the aim is a realistic assessment of the risk. For low doses, below 50 mSv/year, and when all causes of uncertainty are added, the actual risk might be markedly lower than the risk estimated with the ICRP (1991) carcinogenic risk coefficient and the DRF estimated by ICRP. Future studies should aim at providing direct and more precise assessments of risk coefficients in the low dose region. (Author)

  17. Gamma regularization based reconstruction for low dose CT

    International Nuclear Information System (INIS)

    Zhang, Junfeng; Chen, Yang; Hu, Yining; Luo, Limin; Shu, Huazhong; Li, Bicao; Liu, Jin; Coatrieux, Jean-Louis

    2015-01-01

    Reducing the radiation in computerized tomography is today a major concern in radiology. Low dose computerized tomography (LDCT) offers a sound way to deal with this problem. However, more severe noise in the reconstructed CT images is observed under low dose scan protocols (e.g. lowered tube current or voltage values). In this paper we propose a Gamma regularization based algorithm for LDCT image reconstruction. This solution is flexible and provides a good balance between the regularizations based on l 0 -norm and l 1 -norm. We evaluate the proposed approach using the projection data from simulated phantoms and scanned Catphan phantoms. Qualitative and quantitative results show that the Gamma regularization based reconstruction can perform better in both edge-preserving and noise suppression when compared with other norms. (paper)

  18. Low-dose effects hypothesis and observations on NPP personal

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, R.; Acheva, A.; Boteva, R.; Chobanova, N.; Djounova, J.; Gyuleva, I.; Ivanova, K.; Kurchatova, G.; Milchev, A.; Negoicheva, K.; Nikolov, V.; Panova, D.; Pejankov, I.; Rupova, I.; Stankova, K.; Zacharieva, E. [Radiobiology Department, National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

    2013-07-01

    In the modern world the use of various sources of ionizing radiation is nearly ubiquitous. They have numerous applications in industry, medicine, science, agriculture, etc. Radiation doses to workers nevertheless are commensurable to the natural background exposure. Published data on the health effects of occupational radiation exposure are often contradictory. Addressing the issue of „negative” (bystander effects, genomic instability) and „positive” (adaptive response, radiation hormesis) effects of low doses is important and has a significant social and economic impact. In this paper we summarize the results of our extensive monitoring of nuclear power plant (NPP) staff. We believe it is a cohort suitable for analysis of health effects at low doses, because of their good medical and dosimetric control. Our results rather support the idea of absence of adverse health effects in NPP workers. (author)

  19. Effect of low-dose radiation on ocular circulation

    International Nuclear Information System (INIS)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro

    1999-01-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  20. Cystoid Macular Edema Induced by Low Doses of Nicotinic Acid

    Directory of Open Access Journals (Sweden)

    Daniela Domanico

    2013-01-01

    Full Text Available Cystoid macular edema (CME is a condition that involves the macula, causing painless vision loss. In this paper, we report a case of niacin-induced bilateral cystoid macular edema (CME in a middle-age woman taking low dose of niacin (18 mg of nicotinic acid. Optical coherence tomography (OCT showed retinal thickening and cystoid spaces in both eyes, whereas fluorescein angiography (FA; HRA 2, Heidelberg Engineering revealed the absence of fluorescein leakage also in later phases. Four weeks after discontinuation of therapy there were a complete disappearance of macular edema at funduscopic examination and an improvement of visual acuity in both eyes. Furthermore OCT showed a normal retinal profile in both eyes. In our opinion considering the wide availability of niacin, medical monitoring and periodical examination should be considered during niacin administration. To our knowledge, this is the first report in the literature that described the very low-dose niacin-induced bilateral niacin maculopathy.

  1. Effect of low-dose radiation on ocular circulation

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1999-05-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  2. Low-dose radiation-induced endothelial cell retraction

    International Nuclear Information System (INIS)

    Kantak, S.S.; Onoda, J.M.; Diglio, C.A.; Harper Hospital, Detroit, MI

    1993-01-01

    The data presented here are representative of a series of studies designed to characterize low-dose radiation effects on pulmonary microvascular endothelium. Data suggest that post-irradiation lung injuries (e.g. oedema) may be induced with only a single fraction of therapeutic radiation, and thus microscopic oedema may initiate prior to the lethal effects of radiation on the microvascular endothelium, and much earlier than would be suggested by the time course for clinically-detectable oedema. (author)

  3. Late effects of low doses and dose rates

    International Nuclear Information System (INIS)

    Paretzke, H.G.

    1980-01-01

    This paper outlines the spectrum of problems and approaches used in work on the derivation of quantitative prognoses of late effects in man of low doses and dose rates. The origins of principal problems encountered in radiation risks assessments, definitions and explanations of useful quantities, methods of deriving risk factors from biological and epidemiological data, and concepts of risk evaluation and problems of acceptance are individually discussed

  4. Effects of low doses; Effet des faibles doses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B. [Electricite de France (EDF-LAM-SCAST), 93 - Saint-Denis (France)

    2001-07-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  5. Fruit-flies in low-dose exposure experiments

    International Nuclear Information System (INIS)

    Zajnullin, V.G.; Moskalev, A.A.; Shaposhnikov, M.V.; Sheptyakova, A.I.

    2002-01-01

    In vivo exposure of fruit-flies of Drosophila melanogaster line to low doses provided new data indicating that mechanisms of induced genetic instability are involved in radiation-induced alteration of genotype. It is true for increase of genetic variance due to change in transposition number, for change in adaptation capabilities due to modification of gene expression, and for mutability-associated reparation and apoptosis. (author)

  6. Transportable, Low-Dose Active Fast-Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mihalczo, John T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wright, Michael C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McConchie, Seth M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Archer, Daniel E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Palles, Blake A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This document contains a description of the method of transportable, low-dose active fast-neutron imaging as developed by ORNL. The discussion begins with the technique and instrumentation and continues with the image reconstruction and analysis. The analysis discussion includes an example of how a gap smaller than the neutron production spot size and detector size can be detected and characterized depending upon the measurement time.

  7. Biological effects of low doses of ionising radiation

    International Nuclear Information System (INIS)

    Osmak, M.

    1998-01-01

    A study was performed with the aim to examine whether the progeny of cells that had been repeatedly irradiated with low doses of gamma rays will change their sensitivity to cytotoxic agents. Four mammalian cell lines were used in the experiment. It was found that the progeny of cells irradiated in this way do not change their sensitivity to gamma rays but would change their sensitivity to various cytostatics drugs. (A.K.)

  8. Effect of low dose ionizing radiation upon concentration of

    International Nuclear Information System (INIS)

    Viliae, M.; Kraljeviae, P.; Simpraga, M.; Miljaniae, S.

    2004-01-01

    It is known that low dose ionizing radiation might have stimulating effects (Luckey, 1982, Kraljeviae, 1988). This fact has also been confirmed in the previous papers of Kraljeviae et al. (2000-2000a; 2001). Namely, those authors showed that irradiation of chicken eggs before incubation by a low dose of 0.15 Gy gamma radiation increases the activity aspartateaminotrasferases (AST) and alanine-aminotransferases (ALT) in blood plasma of chickens hatched from irradiated eggs, as well as growth of chickens during the fattening period. Low doses might also cause changes in the concentration of some biochemical parameters in blood plasma of the same chickens such as changes in the concentration of total proteins, glucose and cholesterol. In this paper, an attempt was made to investigate the effects of low dose gamma radiation upon the concentration of sodium and potassium in the blood plasma of chickens which were hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy. Obtained results were compared with the results from the control group (chickens hatched from nonirradiated eggs). After hatching, all other conditions were the same for both groups. Blood samples were drawn from heart, and later from the wing vein on days 1, 3, 5, 7, 10, 20, 30 and 42. The concentration of sodium and potassium was determined spectrophotometrically by atomic absorbing spectrophotometer Perkin-Elmer 1100B. The concentration of sodium and potassium in blood plasma of chickens hatched from eggs irradiated on the 19th day of incubation by dose of 0.15 Gy indicated a statistically significant increase (P>0.01) only on the first day of the experiment. Obtained results showed that irradiation of eggs on the 19th day of incubation by dose of 0.15 Gy gamma radiation could have effects upon the metabolism of electrolytes in chickens. (Author)

  9. Low dose monitoring by double implant technique in IC fabrication

    International Nuclear Information System (INIS)

    Ahmad, I.B.; Weidemann, J.

    1995-01-01

    The utilisation of low dose implant monitoring (using Boron) in a manufacturing line has been discussed. The utilisation of phosphorus ions as the second implant dose were also studied as comparison. The technique relies on the fact that the sheet resistant of doped layer will increase significantly when damaged by relatively low implant dose. The technique is very sensitive and applicable for adjusting the channel dose so that an accurate threshold voltage in MOS device could be achieved

  10. adverse effects of low dose methotrexate in rheumatoid arthritis patients

    International Nuclear Information System (INIS)

    Gilani, S.T.; Khan, D.A.; Khan, F.A.; Ahmed, M.

    2012-01-01

    To determine the frequency of adverse effects attributed to Methotrexate (MTX) toxicity and serum minimum toxic concentration with low dose MTX in Rheumatoid Arthritis (RA) patients. Study Design: Cross-sectional observational study. Place and Duration of Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology, Rawalpindi, from March 2010 to March 2011. Methodology: One hundred and forty adult patients of RA receiving low dose MTX (10 mg/week) for at least 3 months, ere included by consecutive sampling. Blood samples were collected 2 hours after the oral dose of MTX. Serum alanine transaminase and creatinine were analyzed on Hitachi and blood counts on Sysmex analyzer. Serum MTX concentration was measured on TDX analyzer. Results: Out of one hundred and forty patients; 68 males (49%) and 72 females (51%), 38 developed MTX toxicity (27%), comprising of hepatotoxicity in 12 (8.6%), nephrotoxicity in 3 (2.1%), anaemia in 8 (5.7%), leucopenia in 2 (1.4%), thrombocytopenia in 3 (2.1%), pancytopenia in 2 (1.4%), gastrointestinal adverse effects in 5 (3.6%) and mucocutaneous problems in 3 (2.1%). Receiver operating characteristic curve revealed serum minimum toxic concentration of MTX at cutoff value of 0.71 mu mol/l with a sensitivity of 71% and specificity of 76%. Conclusion: Adverse effects of low dose MTX were found in 27% of RA patients, mainly comprising of hepatotoxicity and haematological problems. MTX toxicity can be detected by therapeutic drug monitoring of serum concentration of 0.71 mu mol/l with sensitivity of 71% and specificity of 76% in the patients on low dose MTX maintenance therapy. (author)

  11. Global DNA methylation responses to low dose radiation exposure

    International Nuclear Information System (INIS)

    Newman, M.R.; Ormsby, R.J.; Blyth, B.J.; Sykes, P.J.; Bezak, E.

    2011-01-01

    Full text: High radiation doses cause breaks in the DNA which are considered the critical lesions in initiation of radiation-induced cancer. However, at very low radiation doses relevant for the general public, the induction of such breaks will be rare, and other changes to the DNA such as DNA methylation which affects gene expression may playa role in radiation responses. We are studying global DNA methylation after low dose radiation exposure to determine if low dose radiation has short- and/or long-term effects on chromatin structure. We developed a sensitive high resolution melt assay to measure the levels of DNA methylation across the mouse genome by analysing a stretch of DNA sequence within Long Interspersed Nuclear Elements-I (LINE I) that comprise a very large proportion of the mouse and human genomes. Our initial results suggest no significant short-term or longterm) changes in global NA methylation after low dose whole-body X-radiation of 10 J1Gyor 10 mGy, with a significant transient increase in NA methylation observed I day after a high dose of I Gy. If the low radiation doses tested are inducing changes in bal DNA methylation, these would appear to be smaller than the variation observed between the sexes and following the general stress of the sham-irradiation procedure itself. This research was funded by the Low Dose Radiation Research Program, Biological and Environmental Research, US DOE, Grant DE-FG02-05ER64104 and MN is the recipient of the FMCF/BHP Dose Radiation Research Scholarship.

  12. Exercise and Sport Performance with Low Doses of Caffeine

    OpenAIRE

    Spriet, Lawrence L.

    2014-01-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5–13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (

  13. MELODI: The 'Multidisciplinary European Low-Dose Initiative'

    International Nuclear Information System (INIS)

    Belli, M.; Salomaa, S.; Ottolenghi, A.

    2011-01-01

    The importance of research to reduce uncertainties in risk assessment of low and protracted exposures is now recognised globally. In Europe a new initiative, called 'Multidisciplinary European Low Dose Initiative' (MELODI), has been proposed by a 'European High Level and Expert Group on low-dose risk research' (www.hleg.de), aimed at integrating national and EC (Euratom) efforts. Five national organisations: BfS (DE), CEA (FR), IRSN (FR), ISS (IT) and STUK (FI), with the support of the EC, have initiated the creation of MELODI by signing a letter of intent. In the forthcoming years, MELODI will integrate in a step-by-step approach EU institutions with significant programmes in the field and will be open to other scientific organisations and stakeholders. A key role of MELODI is to develop and maintain over time a strategic research agenda (SRA) and a road map of scientific priorities within a multidisciplinary approach, and to transfer the results for the radiation protection system. Under the coordination of STUK a network has been proposed in the 2009 Euratom Programme, called DoReMi (Low-Dose Research towards Multidisciplinary Integration), which can help the integration process within the MELODI platform. DoReMi and the First MELODI Open Workshop, organised by BfS in September 2009, are now important inputs for the European SRA. (authors)

  14. Low dose effects detected by micronucleus assay in lymphocytes

    International Nuclear Information System (INIS)

    Koeteles, G.J.; Bojtor, I.; Kubasova, T.; Horvath, G.

    1997-01-01

    The effects of low doses of X-rays between 0.01 and 1 Gy were studied on whole blood samples of various individuals using the cytokinesis-blocked lymphocyte micronucleus assay as an endpoint. The adaptive response could be induced in G 0 cells by 0.01 Gy followed by 1 Gy challenging dose within a time period of 8 hours, in vitro. The probability distribution of micronucleus increments in those samples which had received very low doses in the range 0.01-0.05 Gy proved to be of asymmetrical type (i.e. lognormal) -very likely to the same shape which has been verified for unirradiated (control) population - while the variable turned to be normally distributed at or above 1 Gy. Profound changes have been experienced in the main characteristics of the linear dose - response relationship and in regression parameters, as well, when successively lessened dose ranges were studied toward 0.01 Gy. In the range below ∼ 0.2 Gy the response were found to be unrelated to the absorbed dose. These findings suggest that in (very) low dose range a higher attention should be needed to biological parameters like repair, protective mechanisms and antioxidant capacities, rather than to the absorbed radiation energy only. (author)

  15. Problems linked to effects of ionizing radiations low doses

    International Nuclear Information System (INIS)

    Anon.

    1995-10-01

    The question of exposure to ionizing radiations low doses and risks existing for professional and populations has been asked again, with the recommendations of the International Commission of Radiation Protection (ICRP) to lower the previous standards and agreed as guides to organize radiation protection, by concerned countries and big international organisms. The sciences academy presents an analysis which concerned on epidemiological and dosimetric aspects in risk estimation, on cellular and molecular aspects of response mechanism to irradiation. The observation of absence of carcinogen effects for doses inferior to 200 milli-sieverts and a re-evaluation of data coming from Nagasaki and Hiroshima, lead to revise the methodology of studies to pursue, to appreciate more exactly the effects of low doses, in taking in part, particularly, the dose rate. The progress of molecular and cellular biology showed that the extrapolation from high doses to low doses is not in accordance with actual data. The acknowledge of DNA repair and carcinogenesis should make clearer the debate. (N.C.). 61 refs., 9 annexes

  16. Low-dose prophylactic craniospinal radiotherapy for intracranial germinoma

    International Nuclear Information System (INIS)

    Schoenfeld, Gordon O.; Amdur, Robert J.; Schmalfuss, Ilona M.; Morris, Christopher G.; Keole, Sameer R.; Mendenhall, William M.; Marcus, Robert B.

    2006-01-01

    Purpose: To report outcomes of patients with localized intracranial germinoma treated with low-dose craniospinal irradiation (CSI) followed by a boost to the ventricular system and primary site. Methods and Materials: Thirty-one patients had pathologically confirmed intracranial germinoma and no spine metastases. Low-dose CSI was administered in 29 patients: usually 21 Gy of CSI, 9.0 Gy of ventricular boost, and a 19.5-Gy tumor boost, all at 1.5 Gy per fraction. Our neuroradiologist recorded three-dimensional tumor size on magnetic resonance images before, during, and after radiotherapy. Results: With a median follow-up of 7.0 years, 29 of 31 patients (94%) are disease free. One failure had nongerminomatous histology; the initial diagnosis was a sampling error. Of 3 patients who did not receive CSI, 1 died. No patient developed myelopathy, visual deficits, dementia, or skeletal growth problems. In locally controlled patients, tumor response according to magnetic resonance scan was nearly complete within 6 months after radiotherapy. Conclusions: Radiotherapy alone with low-dose prophylactic CSI cures almost all patients with localized intracranial germinoma. Complications are rare when the daily dose of radiotherapy is limited to 1.5 Gy and the total CSI dose to 21 Gy. Patients without a near-complete response to radiotherapy should undergo resection to rule out a nongerminomatous element

  17. Ageing effects of polymers at very low dose-rates

    International Nuclear Information System (INIS)

    Chenion, J.; Armand, X.; Berthet, J.; Carlin, F.; Gaussens, G.; Le Meur, M.

    1987-10-01

    The equipment irradiation dose-rate into the containment is variable from 10 -6 to 10 -4 gray per second for the most exposed materials. During qualification, safety equipments are submitted in France to dose-rates around 0.28 gray per second. This study purpose is to now if a so large irradiation dose-rate increase is reasonable. Three elastomeric materials used in electrical cables, o'rings seals and connectors, are exposed to a very large dose-rates scale between 2.1.10 -4 and 1.4 gray per second, to 49 KGy dose. This work was carried out during 3.5 years. Oxygen consumption measurement of the air in contact with polymer materials, as mechanical properties measurement show that: - at very low dose-rate, oxygen consumption is maximum at the same time (1.4 year) for the three elastomeric samples. Also, mechanical properties simultaneously change with oxygen consumption. At very low dose-rate, for the low irradiation doses, oxygen consumption is at least 10 times more important that it is showed when irradiation is carried out with usual material qualification dose-rate. At very low dose-rate, oxygen consumption decreases when absorbed irradiation dose by samples increases. The polymer samples irradiation dose is not still sufficient (49 KGy) to certainly determine, for the three chosen polymer materials, the reasonable irradiation acceleration boundary during nuclear qualification tests [fr

  18. Biochemical and cellular mechanisms of low-dose effects

    International Nuclear Information System (INIS)

    Feinendegen, L.E.; Booz, J.; Muehlensiepen, H.

    1988-01-01

    The question of health effects from small radiation doses remains open. Individual cells, when being hit by single elemental doses - in low-dose irradiation - react acutely and temporarily by altering control of enzyme activity, as is demonstrated for the case of thymidine kinase. This response is not constant in that it provides a temporary protection of enzyme activity against a second irradiation, by a mechanism likely to be via improved detoxification of intracellular radicals. It must be considered that in the low-dose region radiation may also exert protection against other challenges involving radicals, causing a net beneficial effect by temporarily shielding the hit cell against radicals produced by metabolism. Since molecular alterations leading to late effects are considered a consequence of the initial cellular response, late effects from small radiation doses do not necessarily adhere to a linear dose-effect relationship. The reality of the linear relationship between the risk of late effects from high doses to small doses is an assumption, for setting dose limits, but it must not be taken for predicting health detriment from low doses. (author)

  19. Exercise and sport performance with low doses of caffeine.

    Science.gov (United States)

    Spriet, Lawrence L

    2014-11-01

    Caffeine is a popular work-enhancing supplement that has been actively researched since the 1970s. The majority of research has examined the effects of moderate to high caffeine doses (5-13 mg/kg body mass) on exercise and sport. These caffeine doses have profound effects on the responses to exercise at the whole-body level and are associated with variable results and some undesirable side effects. Low doses of caffeine (caffeine doses (1) do not alter the peripheral whole-body responses to exercise; (2) improve vigilance, alertness, and mood and cognitive processes during and after exercise; and (3) are associated with few, if any, side effects. Therefore, the ergogenic effect of low caffeine doses appears to result from alterations in the central nervous system. However, several aspects of consuming low doses of caffeine remain unresolved and suffer from a paucity of research, including the potential effects on high-intensity sprint and burst activities. The responses to low doses of caffeine are also variable and athletes need to determine whether the ingestion of ~200 mg of caffeine before and/or during training and competitions is ergogenic on an individual basis.

  20. Intracranial germinomas: a case for low dose radiation therapy alone

    International Nuclear Information System (INIS)

    Harrigan, Patricia M.; Loeffler, Jay S.; Shrieve, Dennis; Tarbell, Nancy J.

    1995-01-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose ≤ 2550 cGy, and spine dose ≤ 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of ≤ 2550 cGy and 9 pts were treated with spinal RT of ≤ 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of ≤ 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy followed

  1. Intracranial germinomas: a case for low dose radiation therapy alone

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, Patricia M; Loeffler, Jay S; Shrieve, Dennis; Tarbell, Nancy J

    1995-07-01

    Purpose: To determine the optimal dose and treatment outcome of patients treated with radiation for intracranial germinoma. Materials and Methods: Between 1975 and 1995, 39 patients with a diagnosis of intracranial germinoma were treated with radiation (RT) to the central nervous system. All but one pt received whole brain (WB) RT, (median dose: 3240 cGy range: 1500-4437 cGy) and a boost to the tumor volume (median total tumor volume dose: 5200 cGy, range: 3960-5950 cGy). Thirty-one pts received RT to the spine (median dose: 2500, range: 1875-3750). Eleven pts were treated with low dose RT and a tumor volume boost, (WB dose {<=} 2550 cGy, and spine dose {<=} 2160 cGy). Five pts were treated with cisplatin-based chemotherapy and low dose WB RT. Fifteen pts were biopsy-proven and 18 presented with multiple midline germinomas (MMG). Among all pts, 33% had serum or CSF positive for low levels of HCG and none of 19 (9 biopsy-proven) germinomas measured positive for AFP tumor marker. Six of 22 (27%) pts who had spine imaging or CSF cytology had evidence of tumor seeding. The male-to female-ratio was 1.4. Median age at diagnosis was 14 yrs for male pts and 9.5 yrs for females (p=.02, overall age range: 1-31 yrs). Median follow-up for survivors is 64 months (range: 1-226 months). Toxicity of treatment relative to dose was assessed. Results: The 5-yr. actuarial rate of disease-free survival (DFS) and overall survival for presumed germinomas was 97%. No pts died of germinoma. One pt died of a shunt infection who had received concurrent chemotherapy and low dose whole brain RT. Among the low dose RT alone group 6 pts received whole brain RT of {<=} 2550 cGy and 9 pts were treated with spinal RT of {<=} 2160 cGy without chemotherapy. Two of these pts had CSF cytology positive for tumor seeding. Additionally, 8 pts received a total dose to the tumor volume of {<=} 4800 cGy without chemotherapy. The 5-yr DFS was 100%. Five pts were treated with cisplatin-based chemotherapy

  2. Biological effects of low-dose radiation on human population living in high-background radiation areas of Kerala coast

    International Nuclear Information System (INIS)

    Das, Birajalaxmi

    2016-01-01

    High-level natural radiation areas (HLNRA) of Kerala coast is densely populated and known for its wide variation in background radiation dose levels due to uneven distribution of monazite in the beach sand. The background radiation dose varies from 1 to 45 mGv/y. The areas with >1.5mGy/y is considered as HLNRA. Human population inhabiting in this area are exposed to low-dose chronic radiation since generations. Hence, this population provides an ideal situation to study dose response and adaptive response, if any, due to natural chronic low-dose exposure. It has been investigated extensively to study the biological and health effects of long-term low-dose/low-dose radiation exposure. So far over 150, 000 newborns monitored from hospital-based study did not reveal any significant difference in the incidence of any of the malformations and stillbirth between HLNRA and adjacent control areas. A case-control study on cleft lip/palate and mental retardation did not show any association with background radiation dose. Cytogenetic investigation of over 27,000 newborns did not show any significant increase in the frequency of chromosome aberrations and karyotype anomalies. DNA damage endpoints, such as micronuclei, telomere length and DNA strand breaks, did not reveal any significant difference between control and exposed population. Studies on DNA damage and repair revealed efficient repair of DNA strand breaks in HLNRA individuals. Molecular studies using high throughput microarray analysis indicated a large number of genes involved in various molecular and cellular pathways. Indications of in vivo radioadaptive response due to natural chronic low-dose exposure in this population have important implications to human health. (author)

  3. New approach for food allergy management using low-dose oral food challenges and low-dose oral immunotherapies.

    Science.gov (United States)

    Yanagida, Noriyuki; Okada, Yu; Sato, Sakura; Ebisawa, Motohiro

    2016-04-01

    A number of studies have suggested that a large subset of children (approximately 70%) who react to unheated milk or egg can tolerate extensively heated forms of these foods. A diet that includes baked milk or egg is well tolerated and appears to accelerate the development of regular milk or egg tolerance when compared with strict avoidance. However, the indications for an oral food challenge (OFC) using baked products are limited for patients with high specific IgE values or large skin prick test diameters. Oral immunotherapies (OITs) are becoming increasingly popular for the management of food allergies. However, the reported efficacy of OIT is not satisfactory, given the high frequency of symptoms and requirement for long-term therapy. With food allergies, removing the need to eliminate a food that could be consumed in low doses could significantly improve quality of life. This review discusses the importance of an OFC and OIT that use low doses of causative foods as the target volumes. Utilizing an OFC or OIT with a low dose as the target volume could be a novel approach for accelerating the tolerance to causative foods. Copyright © 2015 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  4. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity.

    Science.gov (United States)

    Kudryasheva, N S; Rozhko, T V

    2015-04-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1--absence of effects (stress recognition), 2--activation (adaptive response), and 3--inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Low-dose CT: new tool for screening lung cancer?

    International Nuclear Information System (INIS)

    Diederich, S.; Wormanns, D.; Heindel, W.

    2001-01-01

    Lung cancer is the leading cause of death from malignant tumours as it is very common and has a poor prognosis at advanced tumour stages. Prognosis could be improved by treatment at early stages. As these stages are usually asymptomatic, a diagnostic test that would allow detection of early tumour stages in a population at risk could potentially reduce mortality from lung cancer. Previous approaches using chest radiography and sputum cytology in smokers have been disappointing. Fluorescent bronchoscopy and molecular markers are not yet applicable in clinical routine. Because of its high sensitivity for small pulmonary nodules, which are the most common manifestation of early lung cancer, CT appears suitable as a screening test. Low-dose examination parameters can and should be used for this purpose. From clinical practice it is well known that chest CT often demonstrates small pulmonary nodules, which do not represent lung cancer. Therefore, non-invasive diagnostic algorithms are required to avoid unnecessary biopsies in benign lesions. In preliminary studies of low-dose CT using algorithms based on size and density of detected nodules a large proportion of asymptomatic lung cancers and a large proportion of early, resectable tumour stages were found with a small proportion of invasive procedures for benign nodules. Before this technology can be recommended for broad application, however, further information is required regarding appropriate inclusion criteria (smoking habits, age groups) and screening intervals. Most importantly, further data are required to clarify whether lung cancer screening using low-dose CT can actually reduce mortality from lung cancer. (orig.)

  6. Low-dose multislice CT in febrile neutropenic patients

    International Nuclear Information System (INIS)

    Wendel, F.; Jenett, M.; Hahn, D.; Sandstede, J.; Geib, A.

    2005-01-01

    Purpose: to define the value of low-dose multislice CT in a clinical setting for early detection of pneumonia in neutropenic patients with fever of unknown origin. Materials and methods: thirty-five neutropenic patients suffering from fever of unknown origin with normal chest X-ray underwent unenhanced low-dose CT of the chest (120 kV, 10 eff. mAs, collimation 4 x 1 mm) using a multislice CT scanner. Axial und frontal slices with a thickness of 5 mm were calculated. If no pneumonia was found, standard antibiotics were given and a repeated examination was performed if fever continued. In case of pneumonia, antimycotic therapy was added and a follow-up CT was performed within one week. Regression or progression of pneumonia at follow-up served as evidence of pneumonia; lowering of fever within 48 h or inconspicuous follow-up CT was regarded as absence of pneumonia. Results: ten of 35 patients had pneumonic infiltration, which decreased or increased on follow-up CT in 3 and 6 patients, respectively. One patient revealed leucemic infiltration by bronchoalveolar lavage. Twenty-five of 35 patients had no evidence of pneumonia. Twenty of these patients were free of fever within 48 h under antibiotics; one patient died due to his basic illness. Out of 4 patients with persisting fever, 3 patients had no pneumonia on repeated examination; one patient showed disseminated micronodular infiltration. Frontal reconstructions helped to differentiate infiltration from atelectasis in 4 patients. Sensitivity and specificity for the detection of pneumonia at the first examination were 90% and 96%, negative predictive value was 96%. Conclusion: low-dose multislice CT should be performed in neutropenic patients having a fever of unknown origin and normal chest X-ray. (orig.)

  7. Development of new chemical dosimeter for low dose range

    International Nuclear Information System (INIS)

    Mhatre, Sachin G.V.; Adhikari, S.

    2012-01-01

    Accurate measurement of low dose radiation in complex systems is of utmost importance in radiation biology and related areas. Ferrous Benzoic acid Xylenol orange (FBX) system is being widely used for measurement of low dose gamma radiation because of its reproducibility and precision. However, an additional step, i.e., dissolution of benzoic acid in water at higher temperature followed by cooling at room temperature is involved for the preparation of this dosimeter. This makes it inconvenient as a ready to use dosimeter. In the present work, the organic molecule, sorbitol has been used for measurement of low doses of radiation. The advantages of using sorbitol are its ready availability and instantaneous water solubility. Owing to its dissolution at room temperature, possible errors those are involved in calculation of dose due to thermal oxidation of ferrous ions during preparation of the FBX dosimetric solution could be made insignificant in the proposed dosimeter. In the present system, sorbitol acts as radiolytic sensitizer for the oxidation of ferrous ion, and xylenol orange forms a 1:1 complex specifically with ferric ions. Thus, the analytical detection limit of ferric ions is enhanced compared to other systems. Final composition of the dosimetric solution is; 0.5 mol/m 3 xylenol orange, 10 mol/m 3 sorbitol and 0.2 mol/m 3 ferrous ion in 50 mol/m 3 sulfuric acid. Radiolytic sensitization in combination with analytical enhancement of the ferrous based system, allows us to measure radiation dose in the range of 0.05 Gy–12 Gy with ease and high reproducibility.

  8. Uncommon toxicity of low-dose methotrexate: case report

    Directory of Open Access Journals (Sweden)

    Zohreh Yousefi

    2015-10-01

    Full Text Available Background: Standard treatment of Gestational Trophoblastic Disease (GTD is chemotherapy. Single-agent chemotherapy regime including Methotrexate (MTX or Actinomycin. Single-agent is widely used in treatment of persistent trophoblastic disease. We reported an uncommon toxicity of low-dose single-agent methotrexate in a patient. Case Presentation: A 20-year-old woman, primary gravid after two months missed period and spotting with diagnosis of incomplete abortion with uterine size equivalent of ten weeks pregnancy (8-10 cm underwent evacuation curettage. In serial follow-up, based on rise of beta-hCG titer and absence of metastatic disease, it was categorized as low-risk persistent trophoblastic disease. She was referred to gynecology oncology center of Ghaem Hospital, Mashhad University of Medical Sciences in May 2014. Because of rise of beta-hCG titer, after complete metastatic work-up and lack of disease in other sites, persistent disease was diagnosed and candidate for chemotherapy (single agent low-dose. The patient received first course of therapy with MTX (50 mg/m², intra muscular. Unfortunately, after two days of treatment she developed uncommon severe toxicity, fever, severe nausea and vomiting, tachycardia, and generalized weakness. Also, we found hematologic abnormality (WBC: -14000-15000 µI, platelet- 540 µI and sever neutropenia, and abnormal rising in liver function test (SGOT, SGPT (three to four times and renal function test (BUN and Creatinine (two times. In addition, she had disseminated erosive lesion in all of body especially in face. Due to the fatal side effects of chemotherapy, she was admitted to intensive care unit (ICU. Fortunately, after two to three weeks, she was improved by conservative management. After few weeks beta-hCG titer was in normal limit. However she had normal serial beta-hCG in one year of follow-up. Conclusion: It is important to emphasis unpredictable side effects of chemotherapy with low-dose

  9. Exposure to low dose ionising radiation: Molecular and clinical consequences.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2014-07-10

    This review article provides a comprehensive overview of the experimental data detailing the incidence, mechanism and significance of low dose hyper-radiosensitivity (HRS). Important discoveries gained from past and present studies are mapped and highlighted to illustrate the pathway to our current understanding of HRS and the impact of HRS on the cellular response to radiation in mammalian cells. Particular attention is paid to the balance of evidence suggesting a role for DNA repair processes in the response, evidence suggesting a role for the cell cycle checkpoint processes, and evidence investigating the clinical implications\\/relevance of the effect.

  10. Low-Dose Radiation Induces Genes Promoting Cell Survival

    International Nuclear Information System (INIS)

    Liu, Shu-Zheng; Chen, Dong; Mu, Ying

    1999-01-01

    Apoptosis is an important process controlling homeostasis of the body. It is influenced by stimuli constantly arising from the external and internal environment of the organism. It is well known that radiation could induce apoptosis of cells in vitro and in vivo. However, the dose-effect relationship of apoptosis extending to the low-dose range has scarcely been studied. Here, the molecular basis of the phenomenon is explored by examining the changes in expression of some of the proapoptotic and antiapoptotic genes

  11. A consideration of low dose radiation effects on human health

    International Nuclear Information System (INIS)

    Shimada, Yoshiya; Nishimura, Mayumi; Imaoka, Tatsuhiko; Kakinuma, Shizuko

    2011-01-01

    On March 11, 2011, an earthquake categorized as 9 Mw occurred off the northeast coast of Japan. The subsequent destructive tsunami disabled emergency units of Fukushima Dai'ichi Nuclear Power Plant and caused partial meltdown of reactors and explosions. Resulting radiation releases forced large evacuations, bore concerns about food and water and fears against human health. In this manuscript, we described the effect of radiation, especially low dose radiation below 100 mSv, on cancer risk, focusing on fetuses and children. (author)

  12. Anti-tumor effect of low dose radiation in mice

    International Nuclear Information System (INIS)

    Fan Zhengping; Lu Jiaben; Zhu Bingchai

    1997-01-01

    The author reports the effects of the total body irradiation of low dose radiation (LDR) and/or the local irradiation of large dose on average tumor weights and tumor inhibitory rates in 170 mice inoculated S 180 sarcoma cell, and the influence of LDR on average longevity in 40 tumor-bearing animals. Results show (1) LDR in the range of 75∼250 mGy can inhibit tumor growth to some extent; (2) fractionated irradiation of 75 mGy and local irradiation of 10 Gy may produce a synergism in tumor growth inhibition; and (3)LDR may enhance average longevity in ascitic tumor-bearing mice

  13. Uterine malignant degeneration after low-dose endometrial irradiation

    International Nuclear Information System (INIS)

    Nikkanen, V.; Salmi, T.; Groenroos, M.

    1980-01-01

    The effectiveness of low-dose intrauterine irradiation for benign diseases and its possible carcinogenic effect on the uterus was studied in 190 patients who were treated during the years 1952-1974. The indications for irradiation were premenopausal functional bleeding, leukemia, hemophilia, fibroids, endometriosis or other benign reason. Radiation was also performed on patients with severe neurologic diseases that contraindicated surgery and on some mentally retarded patients whose restlessness and epileptic seizures were aggravated premenstrually and during menstruation. The mean follow-up period was 15 years. Uterine bleeding recurred in 21 percent of the patients. No cases of uterine malignant degeneration were found. (author)

  14. From Chernobyl to Fukushima: the effect of low doses

    International Nuclear Information System (INIS)

    Aurengo, A.

    2011-01-01

    This Power Point presentation describes the Fukushima's reactors, recalls some data about the earthquake and tsunami, and indicates their consequences for the operation of the power station (notably the loss of cooling means). It identifies some design errors for the Chernobyl's and Fukushima's power stations, outlines differences between these two cases. It gives assessment of doses receives by external irradiation around Fukushima, of the dose rate evolution, of the sea contamination. It gives some data about the Chernobyl accident (radioactivity evolution). After some data about health consequences of Chernobyl, health risks and more particularly biological risks associated to low doses are described. Protection measures are evoked, as well as psycho-social impacts

  15. Application of low dose radiation for preservation of sea foods

    International Nuclear Information System (INIS)

    Venugopal, V.; Nair, P.M.

    1994-01-01

    Treatment of food with low doses of gamma radiation has been recognized to have two main advantages. These consist of: (1) improvement of food safety by elimination of pathogens and (2) reduction of microbial spoilage and extension of shelf life of perishable items by reducing the number of viable spoilage organisms. Studies during the last few decades have conclusively proved the beneficial effects of radiation with respect to fishery products. The three potential areas of application to fish products include: (i) radurization for shelf life extension (ii) radicidation to eliminate food borne pathogens in the products and (iii) radiation treatment to dried products to control insects

  16. Suppressing effect of low-dose ionizing radiation on incidence of type I diabetes of NOD mice

    International Nuclear Information System (INIS)

    Nomura, T.; Makino, N.; Oda, T.; Sakai, K.

    2002-01-01

    In the present study we examined the effects of 0.5 Gy of ionizing radiation, given acutely or chronically, on the incidence of type I diabetes in non-obese diabetic mice was examined. NOD mice are characterized by a progressive loss of insulin-producing cells in the pancreas by autoimmune mechanisms. The results suggest that the suppressive effects on the onset of he diabetes by the low dose irradiation are explain by the induction of the antioxidative activity

  17. Biologically based modelling and simulation of carcinogenesis at low doses

    International Nuclear Information System (INIS)

    Ouchi, Noriyuki B.

    2003-01-01

    The process of the carcinogenesis is studied by computer simulation. In general, we need a large number of experimental samples to detect mutations at low doses, but in practice it is difficult to get such a large number of data. To satisfy the requirements of the situation at low doses, it is good to study the process of carcinogenesis using biologically based mathematical model. We have mainly studied it by using as known as 'multi-stage model'; the model seems to get complicated, as we adopt the recent new findings of molecular biological experiments. Moreover, the basic idea of the multi-stage model is based on the epidemiologic data of log-log variation of cancer incidence with age, it seems to be difficult to compare with experimental data of irradiated cell culture system, which has been increasing in recent years. Taking above into consideration, we concluded that we had better make new model with following features: 1) a unit of the target system is a cell, 2) the new information of the molecular biology can be easily introduced, 3) having spatial coordinates for checking a colony formation or tumorigenesis. In this presentation, we will show the detail of the model and some simulation results about the carcinogenesis. (author)

  18. Low doses of neutrons induce changes in gene expression

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Chang-Liu, C.M.; Panozzo, J.; Libertin, C.R.

    1993-01-01

    Studies were designed to identify genes induced following low-dose neutron but not following γ-ray exposure in fibroblasts. Our past work had shown differences in the expression of β-protein kinase C and c-fos genes, both being induced following γ-ray but not neutron exposure. We have identified two genes that are induced following neutron, but not γ-ray, exposure: Rp-8 (a gene induced by apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency (HIV). Rp-8 mRNA induction was demonstrated in Syrian hamster embryo fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.5 cGy/min) and at high dose rate (12 cGy/min). The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measures of CAT activity and CAT transcripts following irradiation demonstrated an unresponsiveness to γ rays over a broad range of doses. Twofold induction of the HIV-LTR was detected following neutron exposure (48 cGy) administered at low (0.5 cGy/min) but not high (12 cGy/min) dose rates. Ultraviolet-mediated HIV-LTR induction was inhibited by low-dose-rate neutron exposure

  19. Low dose iodine-131 therapy in solitary toxic thyroid nodules

    International Nuclear Information System (INIS)

    Prakash, Rajeev

    1999-01-01

    Forty patients with solitary hyperfunctioning thyroid nodules were treated with relatively low dose radioiodine therapy, 131 I doses were calculated taking into account thyroid mass and radioiodine kinetics to deliver 100 μCi/g of estimated nodule weight corrected for uptake. Patients remaining persistently hyperthyroid at four months after the initial therapy were retreated with a similarly calculated dose. Cure of the hyperthyroid state was achieved in all patients, total administered dose in individual cases ranging from 3-17 mCi. 28 of the 40 patients required a single therapy dose. 36 patients were euthyroid after a 4.5 year mean follow-up period. Four cases developed post therapy hypothyroidism requiring replacement therapy. Nodules regressed completely in nine cases following 131 I treatment, with partial regression in size in 19 patients. Control of hyperthyroid state in cases of solitary toxic thyroid nodules can be satisfactorily achieved using relatively low dose radioiodine therapy with low incidence of post therapy hypothyroidism. (author)

  20. Development of microcontroller based instrumentation for low dose implantation

    International Nuclear Information System (INIS)

    Suresh, K.; Saravanan, K.; Panigrahi, B.K.; Nair, K.G.M.

    2011-01-01

    In experiments like ion implantation based ion track formations, the sample is implanted to low doses of the order of 10 10 ions/cm 2 , limiting the ion beam currents to be less than 1-5 x 10 -12 A. However the standard current integrators available are not sensitive to very low currents, causing an unacceptable high level of error in dose measurement. Hence a low dose implantation measurement system has been developed. It consists of a very sensitive low current preamplifier with full scale input 1nA/100pA, a standard current integrator, a microcontroller based interface circuit, which are connected to a personal computer(PC) through USB. Two types of the software are developed for the system: the microcontroller firmware using C and windows based virtual instrument programs using LabVIEW 7.0. Necessary precautions associated with pA level measurement like rigidly fastened good quality cables, low ripple DC power supply, shielding, close mounting of the preamplifier to the sample are adopted. After necessary calibrations with an ECIL make low current source, the system has been put into regular use. Design and development details, salient features are discussed in this paper. (author)

  1. Exposures at low doses and biological effects of ionizing radiations

    International Nuclear Information System (INIS)

    Masse, R.

    2000-01-01

    Everyone is exposed to radiation from natural, man-made and medical sources, and world-wide average annual exposure can be set at about 3.5 mSv. Exposure to natural sources is characterised by very large fluctuations, not excluding a range covering two orders of magnitude. Millions of inhabitants are continuously exposed to external doses as high as 10 mSv per year, delivered at low dose rates, very few workers are exposed above the legal limit of 50 mSv/year, and referring to accidental exposures, only 5% of the 116 000 people evacuated following the Chernobyl disaster encountered doses above 100 mSv. Epidemiological survey of accidentally, occupationally or medically exposed groups have revealed radio-induced cancers, mostly following high dose-rate exposure levels, only above 100 mSv. Risk coefficients were derived from these studies and projected into linear models of risk (linear non-threshold hypothesis: LNT), for the purpose of risk management following exposures at low doses and low dose-rates. The legitimacy of this approach has been questioned, by the Academy of sciences and the Academy of medicine in France, arguing: that LNT was not supported by Hiroshima and Nagasaki studies when neutron dose was revisited; that linear modelling failed to explain why so many site-related cancers were obviously nonlinearly related to the dose, and especially when theory predicted they ought to be; that no evidence could be found of radio-induced cancers related to natural exposures or to low exposures at the work place; and that no evidence of genetic disease could be shown from any of the exposed groups. Arguments were provided from cellular and molecular biology helping to solve this issue, all resulting in dismissing the LNT hypothesis. These arguments included: different mechanisms of DNA repair at high and low dose rate; influence of inducible stress responses modifying mutagenesis and lethality; bystander effects allowing it to be considered that individual

  2. Low-Dose Ribavirin Treatments Attenuate Neuroinflammatory Activation of BV-2 Cells by Interfering with Inducible Nitric Oxide Synthase

    Directory of Open Access Journals (Sweden)

    Iva Bozic

    2015-01-01

    Full Text Available Microglia play a key role in defending central nervous system from various internal and external threats. However, their excessive and/or chronic activation is associated with deleterious effects in a variety of neurodegenerative diseases. Previously, we have shown that ribavirin when applied in clinically relevant dosage (10 μM modulates activated microglia in complex fashion inducing both anti- and proinflammatory effects, simultaneously causing cytotoxicity. Here, we examined potential of low-dose ribavirin (0.1 and 1 μM to modulate activated BV-2 microglia. Morphological and functional activation of BV-2 cells was achieved with lipopolysaccharide (LPS stimulation. Our results demonstrated that low-dose ribavirin did not induce cell death, while 10 μM ribavirin promoted LPS induced apoptosis. We determined that 1 μM ribavirin was equally efficient in deactivation of LPS induced morphological changes as 10 μM ribavirin treatment. Ribavirin showed halfway success in reducing markers of functional activation of microglia. Namely, none of the doses had effect on LPS triggered production of proinflammatory cytokine tumor necrosis factor alpha. On the other hand, low-dose ribavirin proved its effectiveness in reduction of another inflammatory mediator, nitric oxide, by inhibiting inducible form of nitric oxide synthase. Our results imply that low-dose ribavirin may alleviate nitrosative stress during neuroinflammation.

  3. Low-Dose Ribavirin Treatments Attenuate Neuroinflammatory Activation of BV-2 Cells by Interfering with Inducible Nitric Oxide Synthase

    Science.gov (United States)

    Bozic, Iva; Savic, Danijela; Jovanovic, Marija; Bjelobaba, Ivana; Laketa, Danijela; Nedeljkovic, Nadezda; Stojiljkovic, Mirjana; Pekovic, Sanja; Lavrnja, Irena

    2015-01-01

    Microglia play a key role in defending central nervous system from various internal and external threats. However, their excessive and/or chronic activation is associated with deleterious effects in a variety of neurodegenerative diseases. Previously, we have shown that ribavirin when applied in clinically relevant dosage (10 μM) modulates activated microglia in complex fashion inducing both anti- and proinflammatory effects, simultaneously causing cytotoxicity. Here, we examined potential of low-dose ribavirin (0.1 and 1 μM) to modulate activated BV-2 microglia. Morphological and functional activation of BV-2 cells was achieved with lipopolysaccharide (LPS) stimulation. Our results demonstrated that low-dose ribavirin did not induce cell death, while 10 μM ribavirin promoted LPS induced apoptosis. We determined that 1 μM ribavirin was equally efficient in deactivation of LPS induced morphological changes as 10 μM ribavirin treatment. Ribavirin showed halfway success in reducing markers of functional activation of microglia. Namely, none of the doses had effect on LPS triggered production of proinflammatory cytokine tumor necrosis factor alpha. On the other hand, low-dose ribavirin proved its effectiveness in reduction of another inflammatory mediator, nitric oxide, by inhibiting inducible form of nitric oxide synthase. Our results imply that low-dose ribavirin may alleviate nitrosative stress during neuroinflammation. PMID:26413464

  4. Scientific conception on mechanisms of calcium homeostasis disorders under low dose effect of ionizing radiation

    International Nuclear Information System (INIS)

    Abylaev, Zh.A.; Dospolova, Zh.G.

    1997-01-01

    Scientific conception of probable consequences of calcium homeostasis disorders in personals, exposed to low dose effect of ionizing radiation has been developed. Principle positions of the conception is that pathologic processes development have different ways of conducting. During predominance of low doses of external gamma-radiation there is leading pathologic mechanism (mechanism 1) of disorder neuroendocrine regulation of both the calcium and the phosphor. In this case sicks have disorders of both the vegetative tonus and the endocrine status. Under internal irradiation (mechanism 2) there is disfunction of organs and systems (bore changes and disorders of hormone status). These changes are considered as consequence of negative action on organism of incorporated long-living radionuclides. Radio-toxic factors action (mechanism 3) provokes the excess of hormones, which acting on bone tissue and could be cause of steroid osteoporosis. Influence of chronic stress factor (mechanism 4) enlarges and burden action on organism of low radiation doses. It is emphasized, that decisive role in development of pathologic processes has mechanism of disturbance of neuroendocrine regulation of calcium exchange

  5. Facility for gamma irradiations of cultured cells at low dose rates: design, physical characteristics and functioning

    International Nuclear Information System (INIS)

    Esposito, Giuseppe; Anello, Pasquale; Pecchia, Ilaria; Tabocchini, Maria Antonella; Campa, Alessandro

    2016-01-01

    We describe a low dose/dose rate gamma irradiation facility (called LIBIS) for in vitro biological systems, for the exposure, inside a CO_2 cell culture incubator, of cells at a dose rate ranging from few μGy/h to some tens of mGy/h. Three different "1"3"7Cs sources are used, depending on the desired dose rate. The sample is irradiated with a gamma ray beam with a dose rate uniformity of at least 92% and a percentage of primary 662 keV photons greater than 80%. LIBIS complies with high safety standards. - Highlights: • A gamma irradiation facility for chronic exposures of cells was set up at the Istituto Superiore di Sanità. • The dose rate uniformity and the percentage of primary 662 keV photons on the sample are greater than 92% and 80%, respectively. • The GEANT4 code was used to design the facility. • Good agreement between simulation and experimental dose rate measurements has been obtained. • The facility will allow to safely investigate different issues about low dose rate effects on cultured cells.

  6. Multilevel mechanisms of stimulatory effect of low dose radiation on immunity

    International Nuclear Information System (INIS)

    Shu-Zeng Liu

    1992-01-01

    Attention is paid to the effects of low level ionizing radiation on humans. The conference is devoted to low dose radiation and defense mechanisms of the body. Due to the importance of the immune system in body resistance, special attention has been given to host defense mechanisms following exposure to different doses of ionizing radiation. The immune system has long been known to be highly sensitive to moderate to high doses of ionizing radiation with immuno-depression as one of the most important causes of death in acute radiation syndrome. However, the dose-effect relationship of immune functions has been found to be quite different in the low dose range, especially with doses within 0.1 Gy. With doses above 0.5 Gy most immunologic parameters show a dose dependent depression. With doses between 0.1-0.5 Gy there may be no definite changes in immune functions. Doses within 0.1 Gy, given in single or chronic exposures, have been found to stimulate many immune responses. (author). 16 refs., 2 figs., 7 tabs

  7. Immunomodulatory Properties and Molecular Effects in Inflammatory Diseases of Low-Dose X-Irradiation

    International Nuclear Information System (INIS)

    Rödel, Franz; Frey, Benjamin; Manda, Katrin; Hildebrandt, Guido; Hehlgans, Stephanie; Keilholz, Ludwig; Seegenschmiedt, M. Heinrich; Gaipl, Udo S.; Rödel, Claus

    2012-01-01

    Inflammatory diseases are the result of complex and pathologically unbalanced multicellular interactions. For decades, low-dose X-irradiation therapy (LD-RT) has been clinically documented to exert an anti-inflammatory effect on benign diseases and chronic degenerative disorders. By contrast, experimental studies to confirm the effectiveness and to reveal underlying cellular and molecular mechanisms are still at their early stages. During the last decade, however, the modulation of a multitude of immunological processes by LD-RT has been explored in vitro and in vivo. These include leukocyte/endothelial cell adhesion, adhesion molecule and cytokine/chemokine expression, apoptosis induction, and mononuclear/polymorphonuclear cell metabolism and activity. Interestingly, these mechanisms display comparable dose dependences and dose-effect relationships with a maximum effect in the range between 0.3 and 0.7 Gy, already empirically identified to be most effective in the clinical routine. This review summarizes data and models exploring the mechanisms underlying the immunomodulatory properties of LD-RT that may serve as a prerequisite for further systematic analyses to optimize low-dose irradiation procedures in future clinical practice.

  8. Immunomodulatory Properties and Molecular Effects in Inflammatory Diseases of Low-Dose X-Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Rödel, Franz [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany); Frey, Benjamin [Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen (Germany); Manda, Katrin; Hildebrandt, Guido [Department of Radiotherapy and Radiation Oncology, University of Rostock, Rostock (Germany); Hehlgans, Stephanie [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany); Keilholz, Ludwig [Department of Radiotherapy, Clinical Center Bayreuth, Bayreuth (Germany); Seegenschmiedt, M. Heinrich [Strahlenzentrum Hamburg Medizinisches Versorgungszentrum, Hamburg (Germany); Gaipl, Udo S. [Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen (Germany); Rödel, Claus, E-mail: franz.roedel@kgu.de [Department of Radiotherapy and Oncology, University Hospital of Frankfurt, Johann Wolfgang-Goethe Universität, Frankfurt am Main (Germany)

    2012-09-25

    Inflammatory diseases are the result of complex and pathologically unbalanced multicellular interactions. For decades, low-dose X-irradiation therapy (LD-RT) has been clinically documented to exert an anti-inflammatory effect on benign diseases and chronic degenerative disorders. By contrast, experimental studies to confirm the effectiveness and to reveal underlying cellular and molecular mechanisms are still at their early stages. During the last decade, however, the modulation of a multitude of immunological processes by LD-RT has been explored in vitro and in vivo. These include leukocyte/endothelial cell adhesion, adhesion molecule and cytokine/chemokine expression, apoptosis induction, and mononuclear/polymorphonuclear cell metabolism and activity. Interestingly, these mechanisms display comparable dose dependences and dose-effect relationships with a maximum effect in the range between 0.3 and 0.7 Gy, already empirically identified to be most effective in the clinical routine. This review summarizes data and models exploring the mechanisms underlying the immunomodulatory properties of LD-RT that may serve as a prerequisite for further systematic analyses to optimize low-dose irradiation procedures in future clinical practice.

  9. Bolus versus continuous low dose of enalaprilat in congestive heart failure with acute refractory decompensation.

    Science.gov (United States)

    Podbregar, M; Voga, G; Horvat, M; Zuran, I; Krivec, B; Skale, R; Pareznik, R

    1999-01-01

    The first dose of angiotensin-converting enzyme (ACE) inhibitors may trigger a considerable fall of blood pressure in chronic heart failure. The response may be dose-related. To determine hemodynamic and systemic oxygenation effects of low-dose enalaprilat, we administered intravenous enalaprilat (0.004 mg/kg) as bolus (group B) or continuous 1-hour infusion (group C) in 20 patients with congestive heart failure due to ischemic heart disease with acute decompensation refractory to inotropic, vasodilator and diuretic therapy. Hemodynamic and systemic oxygenation variables were recorded at baseline (+0 min), +30, +60, +120, +180, and +360 min after the start of intervention. Mean arterial pressure (MAP) (p < 0. 001), mean pulmonary artery pressure (MPAP) (p < 0.001), pulmonary artery occlusion pressure (PAOP) (p < 0.001), oxygen extraction ratio (ER) (p < 0.026) decreased regardless of enalaprilat application. Compared to group B, there was in group C prolonged decrease of MAP, MPAP, PAOP, ER and increase of pulmonary artery oxyhemoglobin saturation in regard to baseline values. Cardiac index, heart rate, central venous pressure and oxygen consumption index did not change. A low