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Sample records for gamma radiation-induced dna

  1. Gamma radiation-induced heritable mutations at repetitive DNA loci in out-bred mice

    International Nuclear Information System (INIS)

    Somers, C.M.; Sharma, R.; Quinn, J.S.; Boreham, D.R.

    2004-01-01

    Recent studies have shown that expanded-simple-tandem-repeat (ESTR) DNA loci are efficient genetic markers for detecting radiation-induced germ line mutations in mice. Dose responses following irradiation, however, have only been characterized in a small number of inbred mouse strains, and no studies have applied Esters to examine potential modifiers of radiation risk, such as adaptive response. We gamma-irradiated groups of male out-bred Swiss-Webster mice with single acute doses of 0.5 and 1.0 Gy, and compared germ line mutation rates at ESTR loci to a sham-irradiated control. To test for evidence of adaptive response we treated a third group with a total dose of 1.1 Gy that was fractionated into a 0.1 Gy adapting dose, followed by a challenge dose of 1.0 Gy 24 h later. Paternal mutation rates were significantly elevated above the control in the 0.5 Gy (2.8-fold) and 1.0 Gy (3.0-fold) groups, but were similar to each other despite the difference in radiation dose. The doubling dose for paternal mutation induction was 0.26 Gy (95% CI = 0.14-0.51 Gy). Males adapted with a 0.1 Gy dose prior to a 1.0 Gy challenge dose had mutation rates that were not significantly elevated above the control, and were 43% reduced compared to those receiving single doses. We conclude that pre-meiotic male germ cells in out-bred Swiss-Webster mice are sensitive to ESTR mutations induced by acute doses of ionizing radiation, but mutation induction may become saturated at a lower dose than in some strains of inbred mice. Reduced mutation rates in the adapted group provide intriguing evidence for suppression of ESTR mutations in the male germline through adaptive response. Repetitive DNA markers may be useful tools for exploration of biological factors affecting the probability of heritable mutations caused by low-dose ionizing radiation exposure. The biological significance of ESTR mutations in terms of radiation risk assessment, however, is still undetermined

  2. Inhibition of {gamma}-radiation induced DNA damage in plasmid pBR322 by TMG, a water-soluble derivative of vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopalan, R.; Nair, C.K.K. [Bhabha Atomic Research Centre, Mumbai (India); Wani, K.; Huilgol, N.G. [Nanavati Hospital and MRC, Vile Parle (India); Kagiya, Tsutomu V. [Kinki Research Foundation, Kyoto (Japan)

    2002-06-01

    Alpha-tocopherol monoglucoside (TMG), a water-soluble derivative of {alpha}-tocopherol, has been examined for its ability to protect DNA against radiation-induced strand breaks. Gamma radiation, up to a dose of 6 Gy (dose rate, 0.7 Gy/minute), induced a dose-dependent increase in single strand breaks (SSBs) in plasmid pBR322 DNA. TMG inhibited the formation of {gamma}-radiation induced DNA single strand breaks (SSBs) in a concentration-dependent manner; 500 {mu}M of TMG protected the single strand breaks completely. It also protected thymine glycol formation induced by {gamma}-radiation in a dose-dependent manner, based on an estimation of thymine glycol by HPLC. (author)

  3. Repair and gamma radiation-induced single- and double-strand breaks in DNA of Escherichia coli

    International Nuclear Information System (INIS)

    Petrov, S.I.

    1981-01-01

    Studies in the kinetics of repair of γ-radiation-induced single- and double-strand breaks in DNA of E. coli cells showed that double-strand DNA breaks are rejoined by the following two ways. The first way is conditioned by repair of single-strand breaks and represents the repair of ''oblique'' double-strand breaks in DNA, whereas the second way is conditioned by functioning of the recombination mechanisms and, to all appearance, represents the repair of ''direct'' double-strand breaks in DNA

  4. Radiation-induced electron migration along DNA

    International Nuclear Information System (INIS)

    Fuciarelli, A.F.; Sisk, E.C.; Miller, J.H.; Zimbrick, J.D.

    1994-04-01

    Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to nonrandom types of damage along DNA manifested distal to the sites of the initial energy deposition. Electron migration along DNA is significantly influenced by the DNA base sequence and DNA conformation. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution which compares to average migration distances of 6 to 10 bases for Escherichia coli DNA irradiated in solution and 5.5 base pairs for Escherichia coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5' to 3' direction along DNA. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation

  5. Gamma Radiation-Induced Template Polymerization Technique

    International Nuclear Information System (INIS)

    Siyam, T.

    2005-01-01

    Gamma radiation induced copolymerization of acrylamide sodiumacrylate (AM-AANa) in the presence and absence of the polymer additive was studied at low monomer concentration(1.4M/l). The results showed that the exponents of the dose rate for the polymerization rate was found to be 1.3 and 1.4 in the absence and in the presence of the polymer additive respectively. The molecular weight of the formed polymer increased by addition of the polymer to the system. In the presence of the polymer the comonomers polymerize on the added polymer. In the absence of the added polymer the comonomers polymerize according to the copolymerization process at the initial stage of the copolymerization. While at high conversion the residual comonomers polymerize on the formed macromolecular chains of the produced polymer. These studies showed that the copolymerization in the presence of added polymer is completely template copolymerization while in the absence of the polymer the copolymerization process is only template process with a high conversion

  6. Mitigation of gamma-radiation induced abasic sites in genomic DNA by dietary nicotinamide supplementation: Metabolic up-regulation of NAD{sup +} biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Batra, Vipen, E-mail: batravipen@gmail.com; Kislay, Binita

    2013-09-15

    Highlights: • Dietary nicotinamide increases enzyme dependent NAD{sup +} synthesis after irradiation. • Enhanced NAD{sup +} levels mitigate gamma (γ)-radiation induced abasic sites in DNA. • Dietary nicotinamide induces and prolongs expression of excision repair enzymes. • Nicotinamide reduces radiation-generated biomarker (8-oxo-dG) of DNA base damage. • Dietary nicotinamide reduces radiation inflicted DNA damage and delays apoptosis. - Abstract: The search for non-toxic radio-protective drugs has yielded many potential agents but most of these compounds have certain amount of toxicity. The objective of the present study was to investigate dietary nicotinamide enrichment dependent adaptive response to potential cytotoxic effect of {sup 60}Co γ-radiation. To elucidate the possible underlying mechanism(s), male Swiss mice were maintained on control diet (CD) and nicotinamide supplemented diet (NSD). After 6 weeks of CD and NSD dietary regimen, we exposed the animals to γ-radiation (2, 4 and 6 Gy) and investigated the profile of downstream metabolites and activities of enzymes involved in NAD{sup +} biosynthesis. Increased activities of nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide mononucleotide adenylyltransferase (NMNAT) were observed up to 48 h post-irradiation in NSD fed irradiated mice. Concomitant with increase in liver NAMPT and NMNAT activities, NAD{sup +} levels were replenished in NSD fed and irradiated animals. However, NAMPT and NMNAT-mediated NAD{sup +} biosynthesis and ATP levels were severely compromised in liver of CD fed irradiated mice. Another major finding of these studies revealed that under γ-radiation stress, dietary nicotinamide supplementation might induce higher and long-lasting poly(ADP)-ribose polymerase 1 (PARP1) and poly(ADP-ribose) glycohydrolase (PARG) activities in NSD fed animals compared to CD fed animals. To investigate liver DNA damage, number of apurinic/apyrimidinic sites (AP sites) and level of

  7. Relationship between radiation induced activation of DNA repair genes and radiation induced apoptosis in human cell line A431

    International Nuclear Information System (INIS)

    Bom, Hee Seung; Min, Jung Jun; Kim, Kyung Keun; Choi, Keun Hee

    2000-01-01

    The purpose of this study was to evaluate the relationship between radiation-induced acivation of DNA repair genes and radiation induced apoptosis in A431 cell line. Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and ℎRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, ℎRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. ℎRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.=20

  8. Gamma Radiation-Induced Mutations in Soybeans

    International Nuclear Information System (INIS)

    Smutkupt, S.

    1998-01-01

    The main objective of soybean radiation experiments was to create genetic variability in soybeans of various cultivars, mutants and mutation-derived lines with the aim of producing superior breeding lines with resistance to soybean rust (Phakopsora pachyhrizi Syd.) It took altogether 12 generations over six years after gamma irradiation if soybean seeds to produce the best resistant line (81-1-038) which a variety could be developed from it. This Line 81-1-038 showed a very good specific resistance to soybean rust, Thai race 2 and moderately resistance to Thai race 1. In the rainy season of 1985, Line 81-1-038 out yielded S.J.4 (a mother line) by 868 kg/ha in a yield trail at Suwan Farm, Pak Chong, Nakorn Rajchasima. This soybean rust mutant was later named D oi Kham

  9. Radiation induced DNA damage and repair in mutagenesis

    International Nuclear Information System (INIS)

    Strniste, G.F.; Chen, D.J.; Okinaka, R.T.

    1987-01-01

    The central theme in cellular radiobiological research has been the mechanisms of radiation action and the physiological response of cells to this action. Considerable effort has been directed toward the characterization of radiation-induced DNA damage and the correlation of this damage to cellular genetic change that is expressed as mutation or initiating events leading to cellular transformation and ultimately carcinogenesis. In addition, there has been a significant advancement in their understanding of the role of DNA repair in the process of mutation leading to genetic change in cells. There is extensive literature concerning studies that address radiation action in both procaryotic and eucaryotic systems. This brief report will make no attempt to summarize this voluminous data but will focus on recent results from their laboratory of experiments in which they have examined, at both the cellular and molecular levels, the process of ionizing radiation-induced mutagenesis in cultured human cells

  10. Prevention of gamma radiation induced anaemia in mice by diltiazem

    International Nuclear Information System (INIS)

    Nunia, V.; Goyal, P.K.

    2004-01-01

    Intraperitoneal administration of diltiazem (DTZ), half an hour prior to whole body gamma irradiation (2.5, 5.0, and 7.5 Gy), showed the protection of animals from radiation-induced anaemia. Radiation exposure significantly (p<0.001) reduced the number of pro- and normoblasts in bone marrow and red blood cell (RBC) counts, hemoglobin (Hb), hematocrit (Hct), and erythropoietin (EPO) level in blood, but increased myeloid/erythroid ratio. At all the radiation doses, the maximum decrease in these values was noted on the 3rd day, followed by a gradual recovery from the 7th day, but it was not recorded as normal even until the end of experimentation. In animals pretreated with DTZ, these values were measured higher at all the time periods in comparison to corresponding control, and these were almost normal at the last autopsy interval only at 2.5 Gy radiation dose. DTZ maintained the higher EPO level in blood, which acted on bone marrow and spleen colony forming unit for erythroblast (CFU-E), and stimulated such cells to produce RBCs. These results confirm that DTZ has the potency to alter anaemic condition favorably through the protection of bone marrow stem cells, and subsequently it maintains the higher number of pro-and normoblasts in bone marrow, RBC counts, Hb, Hct percentage, and EPO level in blood and the lower myeloid/erythroid ratio in bone marrow. (author)

  11. Comparison of gamma radiation - induced effects in two human prostate cancer cells

    International Nuclear Information System (INIS)

    Vucic, V.; Adzic, M.; Ruzdijic, S.; Radojcic, M.B. . E-mail address of corresponding author: vesnav@vin.bg.ac.yu; Vucic, V.)

    2005-01-01

    In this study, the effects of gamma radiation on two hormone refractory human prostate cancer cell lines, DU 145 and PC-3, were followed. It was shown that gamma radiation induced significant inhibition of cell proliferation and viability in dose dependent manner. Antiproliferative effects of radiation were similar in both cell lines, and more pronounced than cytotoxic effects. In addition to that, PC-3 cell line was more resistant to radiation -induced cytotoxicity. (author)

  12. Gamma radiation induced micronuclei and erythrocyte cellular abnormalities in the fish Catla catla

    Energy Technology Data Exchange (ETDEWEB)

    Anbumani, S. [Biodosimetry Laboratory, Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu 603102 (India); Mohankumar, Mary N., E-mail: marynmk@rediffmail.com [Biodosimetry Laboratory, Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu 603102 (India)

    2012-10-15

    Ionizing radiation induced DNA damage in fishes is a scarcely studied topic and very few studies are available in fishes exposed to ionizing radiation using the erythrocyte micronucleus assay under laboratory conditions. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of high and low levels of radiation that may ultimately result in ionizing radiation exposure to both humans and non-human biota. Fresh water fish, Catla catla were subjected to protracted (0.002 Gy/min) and acute (3.2 Gy/min) gamma radiation to a total dose of 5 Gy. Peripheral blood samples were collected at different intervals (days 3, 6, 12, 18, 30, 45, 90, 135, 202) and analyzed by the erythrocyte micronucleus assay. Nuclear anomalies observed were micronuclei (MN), deformed nuclei (DN), nuclear bud (NBu), nuclear bridge (NBr), vacuolated nucleus (VN), binucleated cell (BNC), apoptotic cells (AC) while cytoplasmic abnormalities detected were vacuolated cytoplasm (VC), anisochromasia (AN), echinocytes (EC) and enucleus (EN). Both exposures caused a statistically significant increase in nuclear and cytoplasmic abnormalities that correlated with micronucleus and other nuclear anomalies. However, the extent of damage is higher after an acute exposure lasting for a longer period leading to apoptosis. Nuclear and cytoplasmic abnormalities are the resultants of gamma radiation induced genotoxicity and cytotoxicity.

  13. Radiation induced chromosome aberrations and interphase DNA geometry

    International Nuclear Information System (INIS)

    Nasazzi, N.; Di Giorgio, M.; Otero, D.

    1995-01-01

    Ionizing radiation induces DNA double strand breaks (DSBs) and their interaction and illegitimate recombination produces chromosome aberrations. Stable chromosome aberrations comprise inter-chromosomal events (translocations) and intra-chromosomal events (inversions). Assuming DSBs induction and interaction is completely random and neglecting proximity effects, the expected ratio of translocations to inversions is F=86, based on chromosome arm lengths. We analyzed the number of translocations and inversions using G-banding, in 16 lymphocyte cultures from blood samples acutely irradiated with γ-rays (dose range: 0.5Gy-3Gy). Our results give F=13.5, significantly smaller than F=86. Literature data show similar small F values but strongly spread. The excess of inversions could be explained by a 'proximity effect', it means that more proximate DSBs have an extra probability of interaction. Therefore, it is possible to postulate a special chromosome arrangement during irradiation and the subsequent interval. We propose a model where individual chromosomes show spherical confinement with some degree of overlapping and DSBs induction proportional to cross section. We assume a DSBs interaction probability function with cut-off length = 1 μ. We propose that large spread in F data could be due to temporal variation in overlapping and spatial chromosome confinement. (author). 14 refs

  14. Modulation of radiation induced DNA damage by natural products in hemopoietic tissue of mice

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2014-01-01

    from the radiation induced DNA damage in spleenocytes. The data on DNA damage analysis by comet assay also showed significant reduction in radiation induced DNA damage in peripheral blood leukocytes of mice pre-treated with taurine. (author)

  15. Gamma radiation induced effects on slaughterhouse wastewater treatment

    International Nuclear Information System (INIS)

    Melo, Rita; Cabo Verde, Sandra; Branco, Joaquim; Botelho, M. Luisa

    2008-01-01

    A preliminary study using gamma radiation on slaughterhouse wastewater samples was carried out. Chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) results were obtained at a dose rate of 0.9 kGy h -1 . A decrease of COD, BOD and colour was observed after irradiation at high absorbed doses. The microbiological results, following irradiation in the same conditions, correlated with the BOD results. The results obtained highlight the potential of this technology for wastewater treatment

  16. Gamma radiation-induced synthesis and characterization of Polyvinylpyrrolidone nanogels

    Science.gov (United States)

    Ges, A. A.; Viltres, H.; Borja, R.; Rapado, M.; Aguilera, Y.

    2017-01-01

    Due to the importance of bioactive peptides, proteins and drug for pharmaceutical purpose, there is a growing interest for suitable delivery systems, able to increase their bioavailability and to target them to the desired location. Some of the most studied delivery systems involve encapsulation or entrapment of drugs into biocompatible polymeric devices. A multitude of techniques have been described for the synthesis of nanomaterials from polymers, however, the use of ionizing radiation (γ, e-), to obtain nano- and microgels polymer is characterized by the possibility of obtaining products with a high degree of purity. Although, in the world, electronic radiation is used for this purpose, gamma radiation has not been utilized for these purposes. In this paper is developed the formulation the formulation of Polyvinylpyrrolidone (PVP) nanogels synthesized by gamma radiation techniques, for their evaluation as potential system of drug delivery. Experiments were performed in absence of oxygen using aqueous solutions of PVP (0.05% -1%). Crosslinking reactions were carried out at 25° C in a gamma irradiation chamber with a 60Co source (MPX-γ 30). The Viscosimetry, Light Scattering, X-Ray Diffraction and Transmission Electron Microscopy (TEM), were used as characterization techniques.

  17. Gamma radiation induced effects on slaughterhouse wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Rita [Departamento de Fisica, Instituto Tecnologico e Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavem (Portugal)], E-mail: ritamelo@itn.pt; Cabo Verde, Sandra [Departamento de Fisica, Instituto Tecnologico e Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavem (Portugal); Branco, Joaquim [Departamento de Quimica, Instituto Tecnologico e Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavem (Portugal); Botelho, M. Luisa [Departamento de Fisica, Instituto Tecnologico e Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavem (Portugal)

    2008-01-15

    A preliminary study using gamma radiation on slaughterhouse wastewater samples was carried out. Chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) results were obtained at a dose rate of 0.9 kGy h{sup -1}. A decrease of COD, BOD and colour was observed after irradiation at high absorbed doses. The microbiological results, following irradiation in the same conditions, correlated with the BOD results. The results obtained highlight the potential of this technology for wastewater treatment.

  18. Gamma radiation induced mutant for improved yield components in sunflower

    International Nuclear Information System (INIS)

    Elangovan, M.

    2001-01-01

    Sunflower has become an important oilseed in the Indian vegetable oil pool following its introduction from Russia in 1969. It can be used for all quality products useful to humans. The need for genetic variability and new useful gene sources has necessitated that sunflower breeders and geneticists utilize a wide range of germplasm in their breeding programmes. The induction of mutations in sunflower by physical and chemical mutagens has been practiced quite intensively in the last two decades. The results recorded to date suggest that utilization of mutagenesis could be a great advantage in improving the sunflower crop. An induced mutation programme was undertaken to generate variability in the variety 'Morden' using gamma rays. The certified and genetically pure seeds were irradiated with 50, 100, and 150 Gy gamma rays and used for further studies. Selection in M 2 generations, raised from different treatments, revealed the presence of an erectophylly leaf mutant from 50 Gy treatment. The isolated mutant showed improved yield components like head diameter, 100- seed weight and yield per plant. The mutant was a plant with short petiole length and erect leaves. This type of leaf get sunlight throughout the day. From morning to afternoon, the first half of the leaf gets sunlight, and from afternoon to evening the second half of the leaf gets sunlight. As a result of getting sunlight the whole day, the plant had more photosynthetic products and grew vigorously. Plant height, head diameter and 100-seed weight had direct effect on seed yield, and the number of leaves and stem diameter influenced the seed yield indirectly. In the M 3 generation, the mutant showed an almost two-fold increase over the parent variety for all investigated characters, except that of the yield per plant where there was a three-fold increase. The present investigation has shown that there are remarkable possibilities of increasing the yield components in sunflower by induced mutations

  19. DNA Double-Strand Break Analysis by {gamma}-H2AX Foci: A Useful Method for Determining the Overreactors to Radiation-Induced Acute Reactions Among Head-and-Neck Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Goutham, Hassan Venkatesh; Mumbrekar, Kamalesh Dattaram [Division of Radiobiology and Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India); Vadhiraja, Bejadi Manjunath [Manipal Hospital, Bangalore, Karnataka (India); Fernandes, Donald Jerard; Sharan, Krishna [Department of Radiotherapy and Oncology, Shiridi Sai Baba Cancer Hospital and Research Centre, Kasturba Hospital, Manipal, Karnataka (India); Kanive Parashiva, Guruprasad; Kapaettu, Satyamoorthy [Division of Biotechnology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India); Bola Sadashiva, Satish Rao, E-mail: satishraomlsc@gmail.com [Division of Radiobiology and Toxicology, Manipal Life Sciences Centre, Manipal University, Manipal, Karnataka (India)

    2012-12-01

    Purpose: Interindividual variability in normal tissue toxicity during radiation therapy is a limiting factor for successful treatment. Predicting the risk of developing acute reactions before initiation of radiation therapy may have the benefit of opting for altered radiation therapy regimens to achieve minimal adverse effects with improved tumor cure. Methods and Materials: DNA double-strand break (DSB) induction and its repair kinetics in lymphocytes of head-and-neck cancer patients undergoing chemoradiation therapy was analyzed by counting {gamma}-H2AX foci, neutral comet assay, and a modified version of neutral filter elution assay. Acute normal tissue reactions were assessed by Radiation Therapy Oncology Group criteria. Results: The correlation between residual DSBs and the severity of acute reactions demonstrated that residual {gamma}-H2AX foci in head-and-neck cancer patients increased with the severity of oral mucositis and skin reaction. Conclusions: Our results suggest that {gamma}-H2AX analysis may have predictive implications for identifying the overreactors to mucositis and skin reactions among head-and-neck cancer patients prior to initiation of radiation therapy.

  20. Protective role of garlic against gamma radiation induced histological and histochemical changes in rat liver

    International Nuclear Information System (INIS)

    Abdel Motaal, N.A.; Abdel Maguid, A.

    2007-01-01

    The present work was planned to evaluate the radioprotective effect of garlic (Allium sativum) against the hazardous action of gamma radiation on liver of rat one and ten days post-exposure. Garlic was orally administered (100 mg/ kg body wt) to rats daily for two weeks before exposure to single dose whole body gamma-irradiation (5Gy). The results showed that exposure of rats to gamma- irradiation caused massive portal infiltration with inflammatory cells, dilatation of blood sinusoids, an increase in the number of Kupffer cells, vacuolation of some hepatocytes as well as pyknosis and karyolysis of hepatic nuclei in the liver tissue. Histochemical examination of liver one day post- irradiation illustrated weak to moderate glycogen particles. While, on ten days post-irradiation, a strong activity for glycogen was detected. The disturbance in carbohydrate metabolism is closely related to the radiation induced histological damage in the liver tissue. Administration of garlic for 2 weeks pre-irradiation reduced the radiation induced histopathological changes and showed marked protection against the tissue damaging effect of radiation. It could be concluded that treatment of rats with garlic before exposure to gamma-irradiation offered a noticeable radioprotective effect of the studied organ

  1. Protective effects of Nigella sativa on gamma radiation-induced jejunal mucosal damage in rats.

    Science.gov (United States)

    Orhon, Zeynep Nur; Uzal, Cem; Kanter, Mehmet; Erboga, Mustafa; Demiroglu, Murat

    2016-05-01

    The aim of this study was to compare the efficacy of Nigella sativa in protection of jejunal mucosa against harmful effects of gamma radiation. Radiotherapy group received abdominal gamma radiation of 15Gy in addition to physiological saline. Radiotherapy+Nigella sativa treatment group received abdominal gamma radiation of 15Gy in addition to Nigella sativa treatment in the amount of 400mg/kg. Radiotherapy and treatment groups were sacrificed 3 days after the exposure to irradiation. Then, jejunum samples were harvested for biochemical and histological assessment of mucosal injury. Nigella sativa treatment was found to significantly lower elevated tissue malondialdehyde (MDA) levels and, to raise reduced glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity in intestinal tissues samples. Single dose 15Gy gamma-irradiation was noted to result in a marked jejunal mucosal injury. Three days after exposure to irradiation, the villi and Lieberkühn crypts were observed as denuded, and villous height diminished. Concomitantly with inflammatory cell invasion, capillary congestion and ulceration were observed in the atrophic mucosa. Nigella sativa treatment significantly attenuated the radiation induced morphological changes in the irradiated rat jejunal mucosa. Nigella sativa has protective effects against radiation-induced damage, suggesting that clinical transfer is feasible. Copyright © 2016 Elsevier GmbH. All rights reserved.

  2. Activity of Lactobacillus casei and its gamma-radiation induced mutant in different types of milk

    International Nuclear Information System (INIS)

    Singh, J.; Ranganathan, B.

    1979-01-01

    Lactobacillus casei (RTS) and one of its gamma-radiation induced mutants, selected on the basis of increased proteolytic activity were individually inoculated in skimmed milk samples of different species. After incubation at 37 0 C for 24 hours, both the cultures produced higher titratable and volatile acidities and liberated more tyrosine in buffalo's milk as compared to either cow's or goat's milk. These cultures did not produce diacetyl or acetoin in different types of milk. It was further observed that the mutant was biochemically more active as compared to the parent culture. L. casei (RTS), irrespective of milk of different species. (orig.) [de

  3. Investigation of gamma radiation induced changes in local structure of borosilicate glass by TDPAC and EXAFS

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ashwani, E-mail: kashwani@barc.gov.in [Bhabha Atomic Research Centre, Radioanalytical Chemistry Division (India); Nayak, C.; Rajput, P. [Bhabha Atomic Research Centre, Atomic and Molecular Physics Division (India); Mishra, R. K. [Bhabha Atomic Research Centre, Waste Management Division (India); Bhattacharyya, D. [Bhabha Atomic Research Centre, Atomic and Molecular Physics Division (India); Kaushik, C. P. [Bhabha Atomic Research Centre, Waste Management Division (India); Tomar, B. S. [Bhabha Atomic Research Centre, Radioanalytical Chemistry Division (India)

    2016-12-15

    Gamma radiation induced changes in local structure around the probe atom (Hafnium) were investigated in sodium barium borosilicate (NBS) glass, used for immobilization of high level liquid waste generated from the reprocessing plant at Trombay, Mumbai. The (NBS) glass was doped with {sup 181}Hf as a probe for time differential perturbed angular correlation (TDPAC) spectroscopy studies, while for studies using extended X-ray absorption fine structure (EXAFS) spectroscopy, the same was doped with 0.5 and 2 % (mole %) hafnium oxide. The irradiated as well as un-irradiated glass samples were studied by TDPAC and EXAFS techniques to obtain information about the changes (if any) around the probe atom due to gamma irradiation. TDPAC spectra of unirradiated and irradiated glasses were similar and reminescent of amorphous materials, indicating negligible effect of gamma radiation on the microstructure around Hafnium probe atom, though the quaqdrupole interaction frequency (ω{sub Q}) and asymmetry parameter (η) did show a marginal decrease in the irradiated glass compared to that in the unirradiated glass. EXAFS measurements showed a slight decrease in the Hf-O bond distance upon gamma irradiation of Hf doped NBS glass indicating densification of the glass matrix, while the cordination number around hafnium remains unchanged.

  4. Radiation-induced luminescence from dry and hydrated DNA and related macromolecules

    International Nuclear Information System (INIS)

    Al-Kazwini, A.T.; O'Neill, P.; Fielden, E.M.; Adams, G.E.

    1988-01-01

    The radiation-induced luminescence from three types of fibrous DNA and a series of polydeoxynucleotides was measured under vacuum or in the presence of oxygen at 77 and 293K. The in-pulse emission spectra, generated by electrons with energies 50% water by wt (1.2:1 w/w, H 2 O/DNA), the in-pulse luminescence spectrum is similar to that of dry DNA. These findings are discussed in terms of energy or charge migration induced in DNA upon irradiation and the possible effects of conformational changes, caused by hydration, on charge migration. (author)

  5. Radiation-induced energy migration within solid DNA: The role of misonidazole as an electron trap

    International Nuclear Information System (INIS)

    Al-Kazwini, A.T.; O'Neill, P.; Adams, G.E.; Fielden, E.M.

    1990-01-01

    The in-pulse luminescence emission from solid DNA produced upon irradiation with electron pulses of energy below 260 keV has been investigated in vacuo at 293 K to gain an insight into the existence of radiation-induced charge/energy migration within DNA. The DNA samples contained misonidazole in the range 3 to 330 base pairs per misonidazole molecule. Under these conditions greater than 90% of the total energy is deposited in the DNA. The in-pulse radiation-induced luminescence spectrum of DNA was found to be critically dependent upon the misonidazole content of DNA. The luminescence intensity from the mixtures decreases with increasing content of misonidazole, and at the highest concentration, the intensity at 550 nm is reduced to 50% of that from DNA only. In the presence of 1 atm of oxygen, the observed emission intensity from DNA in the wavelength region 350-575 was reduced by 35-40% compared to that from DNA in vacuo. It is concluded that electron migration can occur in solid mixtures of DNA over a distance of up to about 100 base pairs

  6. Wheat Germ Oil Attenuates Gamma Radiation- Induced Skeletal Muscles Damage in Rats

    International Nuclear Information System (INIS)

    Said, U.Z.; Saada, H.N.; Shedid, Sh.M.; Mahdy, E.M.E.; Shousha, W.Gh.

    2008-01-01

    Muscular strength is important in sport as well as in daily activities. Exposure to ionizing radiation is thought to increase oxidative stress and damage muscle tissue. Wheat germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. The present study was designed to investigate the efficacy of wheat germ oil, on radiation-induced oxidative damage in rats skeletal muscle. Wheat germ oil was supplemented orally via gavages to rats at a dose of 54 mg/ kg body weight/day for 14 successive days pre- and 7 post-exposure to 5 Gy (one shot dose) of whole body gamma irradiation. Animals were sacrificed 7, 14 and 21 days post radiation exposure. The results revealed that whole body gamma-irradiation of rats induces oxidative stress in skeletal muscles obvious by significant elevation in the level of thiobarbituric acid reactive substances (TBARS) associated with significant decreases in the content of reduced glutathione (GSE1), as well as decreases in superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities. Irradiated rats showed, also, significant decreases in creatine phosphokinase (CPK), glutamate dehydrogenase (GDH) and glucose-6-phosphate dehydrogenase (G-6-PD) activities. Furthermore, total iron, total copper and total calcium levels were significantly increased in skeletal muscles of irradiated rats group compared to control group. Wheat germ oil treated-irradiated rats showed significantly less sever damage and remarkable improvement in all the measured parameters, compared to irradiated rats. It could be concluded that wheat germ oil by attenuating radiation induced oxidative stress might play a role in maintaining skeletal muscle integrity

  7. Effectiveness of grape seed extract on gamma radiation-induced hazards in albino rats

    International Nuclear Information System (INIS)

    Abd El Azime, A.S.

    2008-01-01

    The present study was designed to determine the possible protective effect of grape seed extract (GSE), rich in proanthocyanidins against gamma radiation-induced oxidative stress associated to serum metabolic disorders in the liver, heart and pancreas tissues of rats. Male albino rats received GSE (100 mg/day/Kg body weight), by gavages, for 14 successive days before whole body exposure to 5 Gy gamma radiation (shot dose). Animals were sacrificed 1, 14, and 28 days post radiation exposure. The results showed that in the irradiated group, tissues superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) activities were decreased significantly, while thiobarbituric acid reactive substances (TBARS) content was increased, which was in parallel with significant increases in the activity of serum lactate dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate and alanine aminotransferase (AST and ALT). Hyperglycemia, hyperinsulinaemia, hyperlipidaemia, decreases in red blood cells count (RBCs) count and hemoglobin (Hb) content were also observed in irradiated rats. n the GSE-treated irradiated group, significant increases of SOD, CAT, and GSH-Px activities with significant reduction of TBARS levels were observed in cardiac, liver, and pancreas tissues, in parallel to significant decreases in the activity of serum LDH, CPK, AST, and ALT compared with their corresponding values in the irradiated group. Moreover, serum glucose and insulin contents, RBCs count and Hb content were significantly improved in the GSE-treated irradiated rats. Furthermore, the marked increase in serum triglycerides and total cholesterol observed in irradiated rats, along with elevated LDL-C and decreased HDL-C levels were significantly improved in GSE treated rats. In conclusion, the present data demonstrate that GSE through its free radical scavenging and antioxidant properties attenuates ionizing radiation-induced oxidative injury suggesting that it may be a potential

  8. Radiation-Induced Graft Polymerization: Gamma Radiation and Electron Beam Technology for Materials Development

    International Nuclear Information System (INIS)

    Madrid, Jordan F.; Cabalar, Patrick Jay; Lopez, Girlie Eunice; Abad, Lucille V.

    2015-01-01

    The formation of functional hybrid materials by attaching polymer chains with advantageous tailored properties to the surface of a base polymer with desirable bulk character is an attractive application of graft copolymerization. Radiation-induced graft polymerization (RIGP) has been a popular approach for surface modification of polymers because of its merits over conventional chemical processes. RIGP, which proceeds primarily via free radical polymerization process, has the advantages such as simplicity, low cost, control over process and adjustment of the materials composition and structure. RIGP can be performed using either electron beam or gamma radiation and it can be applied to both synthetic and natural polymers. These merits make RIGP a popular research topic worldwide. Moreover, the materials synthesized and produced via RIGP has found applications, and were proposed to produce continuous impact, in the fields of medicine, agriculture, pollution remediation, rare earth and valuable metals recovery, fuel cell membrane synthesis and catalysis to name a few. From 2012 our group has performed electron beam and gamma radiation-induced graft polymerization of various monomers onto polymers of natural and synthetic origins (e.g. monomers - glycidyl methacrylate, styrene, acrylonitrile, N,N-dimethylaminoethyl methacrylate; base polymers – polyethylene/polypropylene nonwoven fabric, polypropylene nonwoven fabric pineapple fibers, cellulose nonwoven fabric microcrystalline cellulose). We tested these grafted materials for heavy metals (Pb, Ni, Cu) and organic molecule removal from aqueous solutions and E. coli activity (using reversible addition fragmentation chain transfer RAFT mediated grafting). The results clearly showed the success of materials modified via FIGP in these applications. Currently, we are studying the applications of grafted materials on treatment of waste waters from tanning industry, value addition to abaca nonwoven fabrics cell sheet

  9. Microfabricated electrochemical sensor for the detection of radiation-induced DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Rivas, G.; Ozsoz, M.; Grant, D.H.; Cai, X.; Parrado, C. [New Mexico State Univ., Las Cruces, NM (United States)

    1997-04-01

    An electrochemical biosensor protocol for the detection of radiation-induced DNA damage is described. The procedure employs a dsDNA-coated screen-printed electrode and relies on changes in the guanine-DNA oxidation signal upon exposure to ultraviolet radiation. The decreased signal is ascribed primarily to conformational changes in the DNA and to the photoconversion of the guanine-DNA moiety to a nonelectroactive monomeric base product. Factors influencing the response of these microfabricated DNA sensors, such as irradiation time, wavelength, and distance, are explored, and future prospects are discussed. Similar results are given for the use of bare strip electrodes in connection with irradiated DNA solutions. 8 refs., 4 figs.

  10. Protective effect of peach kernel extracts on radiation-induced DNA damage in human blood lymphocytes in the comet assay

    International Nuclear Information System (INIS)

    Kim, Jin Kyu; Lee, Chang Joo; Park, Tae Won; Chai, Young Gyu

    1999-01-01

    The alkaline single-cell gel electrophoresis (SCGE) assay, the comet assay, has been applied to the detection of DNA damage from a number of chemical and biological factors in vivo and in vitro. The comet assay is a novel method to assess DNA single-strand breaks, alkali-labile sites in individual cells. We evaluated the effect of peach kernel extracts on radiation-induced DNA damage in human blood lymphocytes using the comet assay. The lymphocytes, with or without pretreatment of the extracts, were exposed to 0, 0.1, 0.3, 0.5, 1.0 and 2.0 Gy of 60 Co gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in the comet assay, showed an excellent dose-response relationship. The treatment of the peach kernel extracts prominently reduced the DNA damage in irradiated groups compared to that in non-treated control groups. The result indicated that the extracts showed radioprotective effect on lymphocyte DNA when assessed by the comet assay

  11. Radiation induced apoptosis and initial DNA damage are inversely related in locally advanced breast cancer patients

    International Nuclear Information System (INIS)

    Pinar, Beatriz; Henríquez-Hernández, Luis Alberto; Lara, Pedro C; Bordon, Elisa; Rodriguez-Gallego, Carlos; Lloret, Marta; Nuñez, Maria Isabel; De Almodovar, Mariano Ruiz

    2010-01-01

    DNA-damage assays, quantifying the initial number of DNA double-strand breaks induced by radiation, have been proposed as a predictive test for radiation-induced toxicity. Determination of radiation-induced apoptosis in peripheral blood lymphocytes by flow cytometry analysis has also been proposed as an approach for predicting normal tissue responses following radiotherapy. The aim of the present study was to explore the association between initial DNA damage, estimated by the number of double-strand breaks induced by a given radiation dose, and the radio-induced apoptosis rates observed. Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp). Radio-induced apoptosis at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide. Radiation-induced apoptosis increased in order to radiation dose and data fitted to a semi logarithmic mathematical model. A positive correlation was found among radio-induced apoptosis values at different radiation doses: 1, 2 and 8 Gy (p < 0.0001 in all cases). Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46). A statistically significant inverse correlation was found between initial damage to DNA and radio-induced apoptosis at 1 Gy (p = 0.034). A trend toward 2 Gy (p = 0.057) and 8 Gy (p = 0.067) was observed after 24 hours of incubation. An inverse association was observed for the first time between these variables, both considered as predictive factors to radiation toxicity

  12. Measurement of 60CO gamma radiation induced attenuation in multimode step-index POF at 530 nm

    Directory of Open Access Journals (Sweden)

    Kovačević Milan S.

    2013-01-01

    Full Text Available As optical fibres are used ever more extensively in space applications, nuclear industry, medicine and high-energy physics experiments, it has become essential to investigate the influence of ionizing radiation on their characteristics. In this work, the radiation-induced attenuation at 530 nm is investigated experimentally in step-index multimode polymethyl-methacrylate plastic optical fibres exposed to low dose-rate gamma radiation. Cumulative doses ranged from 50 Gy to 500 Gy. The radiation induced attenuation has been empirically found to obey the power law RIA= aDb, where D is the total radiation dose and a and b are the constants determined by fitting.

  13. Repair of radiation-induced DNA damage in rat epidermis as a function of age

    International Nuclear Information System (INIS)

    Sargent, E.V.; Burns, F.J.

    1985-01-01

    The rate of repair of radiation-induced DNA damage in proliferating rat epidermal cells diminished progressively with increasing age of the animal. The dorsal skin was irradiated with 1200 rad of 0.8 MeV electrons at various ages, and the amount of DNA damage was determined as a function of time after irradiation by the method of alkaline unwinding followed by S 1 nuclease digestion. The amount of DNA damage immediately after irradiation was not age dependent, while the rate of damage removal from the DNA decreased with increasing age. By fitting an exponential function to the relative amount of undamaged DNA as a function of time after irradiation, DNA repair halftimes of 20, 27, 69, and 107 min were obtained for 28, 100-, 200-, and 400-day-old animals, respectively

  14. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Praveen Kumar, M.K., E-mail: here.praveen@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Shyama, S.K., E-mail: skshyama@gmail.com [Department of Zoology, Goa University, Goa 403206 (India); Sonaye, B.S. [Department of Radiation Oncology, Goa Medical College, Goa (India); Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A. [Department of Zoology, Goa University, Goa 403206 (India); Chaubey, R.C. [Radiation Biology and Health Science Division, Bhabha Atomic Research Centre, Mumbai (India)

    2014-05-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  15. Evaluation of γ-radiation-induced DNA damage in two species of bivalves and their relative sensitivity using comet assay

    International Nuclear Information System (INIS)

    Praveen Kumar, M.K.; Shyama, S.K.; Sonaye, B.S.; Naik, U Roshini; Kadam, S.B.; Bipin, P.D.; D’costa, A.; Chaubey, R.C.

    2014-01-01

    Highlights: • Possible genotoxic effect of accidental exposure of aquatic fauna to γ radiation. • Relative sensitivity of bivalves to γ radiation is also analyzed using comet assay. • γ radiation induced significant genetic damage in both the species of bivalves. • P. malabarica and M. casta exhibited a similar level of sensitivity to γ radiation. • Comet assay may be used as a biomarker for the environmental biomonitoring. - Abstract: Ionizing radiation is known to induce genetic damage in diverse groups of organisms. Under accidental situations, large quantities of radioactive elements get released into the environment and radiation emitted from these radionuclides may adversely affect both the man and the non-human biota. The present study is aimed (a) to know the genotoxic effect of gamma radiation on aquatic fauna employing two species of selected bivalves, (b) to evaluate the possible use of ‘Comet assay’ for detecting genetic damage in haemocytes of bivalves as a biomarker for environmental biomonitoring and also (c) to compare the relative sensitivity of two species of bivalves viz. Paphia malabarica and Meretrix casta to gamma radiation. The comet assays was optimized and validated using different concentrations (18, 32 and 56 mg/L) of ethyl methanesulfonate (EMS), a direct-acting reference genotoxic agent, to which the bivalves were exposed for various times (24, 48 and 72 h). Bivalves were irradiated (single acute exposure) with 5 different doses (viz. 2, 4, 6, 8 and 10 Gy) of gamma radiation and their genotoxic effects on the haemocytes were studied using the comet assay. Haemolymph was collected from the adductor muscle at 24, 48 and 72 h of both EMS-exposed and irradiated bivalves and comet assay was carried out using standard protocol. A significant increase in DNA damage was observed as indicated by an increase in % tail DNA damage at different concentrations of EMS and all the doses of gamma radiation as compared to controls in

  16. {gamma}-Radiation-induced follicular degeneration in the prepubertal mouse ovary

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Joo [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Yoon, Yong-Dal [Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)]. E-mail: ydyoon@hanyang.ac.kr

    2005-10-15

    Prepubertal mice were whole-body irradiated with a mean lethal dose (LD{sub 50}) of {gamma}-radiation using a {sup 60}Co source with a total dose of 7.2 Gy and a dose rate of 12.0 cGy/min. At day 0 before the irradiation and at day 1, 2, and 3 after the irradiation, the ovaries were collected and the morphological changes were assessed. The ratios (%) of atretic or polymorphonuclear leukocytes (neutrophil)-infiltrated follicles in the largest cross sections were calculated. In the early atretic follicle of the control mouse ovary, both apoptotic and mitotic cells were observed and occasionally neutrophils were infiltrated into the follicle cavity. However, in the atretic follicles 2 days post-irradiation, numerous cell fragments, apoptotic cells and bodies, and especially, a number of neutrophils were observed. In the non-irradiated control, the ratios of atretic follicles were 58.0 {+-} 8.6 and 27.3 {+-} 11.2 (mean {+-} S.E.M.) in antral and preantral follicles, respectively. The ratios of the number of antral and preantral follicles with one or more neutrophils to the total number of atretic follicles were 29.3 {+-} 12.0. At 2 days post-irradiation, the ratios of atretic follicles were increased to 94.0 {+-} 3.4 and 86.9 {+-} 7.6 in antral and preantral follicles, respectively. The ratios of neutrophil-containing follicles among the atretic one were increased to 65.9 {+-} 11.5 and 57.8 {+-} 15.4 at 2 and 3 days after the irradiation, respectively. Taken together, the present results show that {gamma}-radiation induces apoptotic and inflammatory degeneration of mouse ovarian follicles. Besides, neutrophils may be involved in the acute atretic degeneration in {gamma}-irradiated mouse ovarian follicles.

  17. The effects of radioprotective agents on the radiation-induced DNA single strand breaks

    International Nuclear Information System (INIS)

    Rhiu, Sung Ryul; Ko, Kyung Hwan; Jung, In Yong; Cho, Chul Ku; Kim, Tae Hwan; Park, Woo Wiun; Kim, Sung Ho; Ji, Young Hoon; Kim, Kyung Jung; Bang, Hio Chang; Jung, Young Suk; Choi, Moon Sik

    1992-04-01

    With the increased use of atomic energy in science, industry, medicine and public power production, the probability of nuclear accidents certainly appears to be on the increase. Therefore, early medical diagnosis and first-aid are needed urgently to establish an efficient treatment. We carried out the studies of radiation protector such as DDC, MEA, WR-2721 and variety of decontaminator with a view to establishing the protective measure and diagnostic standards for safety of worker and neighbors living around the radiation area in case of occurring the accidental contamination. In this experiment, we examined radiation-induced DNA single strand breaks as one of the study on molecular biology of the response of cells to radiation because an understanding of the radiation-induced damage in molecular level would add to our knowledge of radiation protection and treatment. (Author)

  18. Radiation-induced DNA Double Strand Breaks and Their Modulations by Treatments with Moringa oleifera Lam. Leaf Extracts: A Cancer Cell Culture Model

    International Nuclear Information System (INIS)

    Boonsirichai, K.; Jetawattana, S.

    2014-01-01

    Gamma radiation brings deleterious effects upon human cells by inducing oxidative stress and DNA damages. Antioxidants have been shown to confer protective effects on irradiated normal cells. Moringa oleifera Lam. is a widely used nutritional supplement with antioxidant activities. This report showed that antioxidant-containing supplements, in addition to protecting normal cells, could protect cancer cells against genotoxic effects of gamma radiation. γ-H2AX immunofluorescent foci were utilized as an indicator of radiation-induced DNA double strand breaks. MCF-7 human breast adenocarcinoma cells were irradiated with 2-8 Gy gamma radiation. A linear relationship between the formation of γ-H2AX foci and radiation dose was observed with an average of 10 foci per cell per Gy. A 30-minute pretreatment of the cells with either the aqueous or the ethanolic extract of M. oleifera leaves could partially protect the cells from radiation-induced DNA double strand breaks. A pretreatment with 500 µg/mL aqueous extract reduced the number of foci formed by 15% when assayed at 30 minutes post-irradiation. The ethanolic extract was more effective; 500 µg/mL of its concentration reduced the number of foci among irradiated cells by 30%. The results indicated that irradiated cancer cells responded similarly to nutritional supplements containing antioxidants as irradiated normal cells. These natural antioxidants could confer protective effects upon cancer cells against gamma radiation. (author)

  19. Radiation-induced DNA Double Strand Breaks and Their Modulations by Treatments with Moringa oleifera Lam. Leaf Extracts: A Cancer Cell Culture Model

    Directory of Open Access Journals (Sweden)

    K. Boonsirichai

    2014-04-01

    Full Text Available Gamma radiation brings deleterious effects upon human cells by inducing oxidative stress and DNA damages. Antioxidants have been shown to confer protective effects on irradiated normal cells. Moringa oleifera Lam. is a widely used nutritional supplement with antioxidant activities. This report showed that antioxidant-containing supplements, in addition to protecting normal cells, could protect cancer cells against genotoxic effects of gamma radiation. -H2AX immunofluorescent foci were utilized as an indicator of radiation-induced DNA double strand breaks. MCF-7 human breast adenocarcinoma cells were irradiated with 2-8 Gy gamma radiation. A linear relationship between the formation of -H2AX foci and radiation dose was observed with an average of 10 foci per cell per Gy. A 30-minute pretreatment of the cells with either the aqueous or the ethanolic extract of M. oleifera leaves could partially protect the cells from radiation-induced DNA double strand breaks. A pretreatment with 500 µg/mL aqueous extract reduced the number of foci formed by 15% when assayed at 30 minutes post-irradiation. The ethanolic extract was more effective; 500 µg/mL of its concentration reduced the number of foci among irradiated cells by 30%. The results indicated that irradiated cancer cells responded similarly to nutritional supplements containing antioxidants as irradiated normal cells. These natural antioxidants could confer protective effects upon cancer cells against gamma radiation

  20. Analysis of ionizing radiation-induced foci of DNA damage repair proteins

    International Nuclear Information System (INIS)

    Veelen, Lieneke R. van; Cervelli, Tiziana; Rakt, Mandy W.M.M. van de; Theil, Arjan F.; Essers, Jeroen; Kanaar, Roland

    2005-01-01

    Repair of DNA double-strand breaks by homologous recombination requires an extensive set of proteins. Among these proteins are Rad51 and Mre11, which are known to re-localize to sites of DNA damage into nuclear foci. Ionizing radiation-induced foci can be visualized by immuno-staining. Published data show a large variation in the number of foci-positive cells and number of foci per nucleus for specific DNA repair proteins. The experiments described here demonstrate that the time after induction of DNA damage influenced not only the number of foci-positive cells, but also the size of the individual foci. The dose of ionizing radiation influenced both the number of foci-positive cells and the number of foci per nucleus. Furthermore, ionizing radiation-induced foci formation depended on the cell cycle stage of the cells and the protein of interest that was investigated. Rad51 and Mre11 foci seemed to be mutually exclusive, though a small subset of cells did show co-localization of these proteins, which suggests a possible cooperation between the proteins at a specific moment during DNA repair

  1. Enhancing repair of radiation-induced strand breaks in cellular DNA as a radiotherapeutic potential

    International Nuclear Information System (INIS)

    Nair, C.K.K.

    2014-01-01

    Protection of mammalian organisms including man from deleterious effects of ionizing radiation is of paramount importance and development of effective approaches to combat radiation damages using non-toxic radioprotectors is of considerable interest for defence, nuclear industries, radiation accidents, space travels, etc., besides the protection of normal tissues during radiotherapy of tumours. Many synthetic as well as natural compounds have been investigated in the recent past for their efficacy to protect the biological systems from radiation induced damages. They include sulfhydryl compounds, antioxidants, plant extracts, immune-modulators, and other agents. However, the inherent toxicity of many of the synthetic agents at the effective radio-protective concentration warranted further search for safer and more effective radio-protectors. In this context, therapeutic radioprotectors which are effective on post irradiation administration are of special relevance. One of the property that can be applied while screening for such radiation protective therapeutics is their ability to enhance repair of radiation-induced lesions in cellular DNA in terms of cellular repair index based on the parameters of the DNA following comet assay. Post irradiation administration of some natural and synthetic agents have shown their potential to enhance repair of radiation-induced strand breaks in cellular DNA in mice. These include phytoceuticals such as gallic acid, sesamol etc., extracts of medicinal plants such as Andrographis panniculata, and a few synthetic compounds such as tocopherol-mono-glucoside. The talk will give an overview of the work on DNA repair enhancement by a few natural and synthetic agents. (author)

  2. Model studies of radiation induced oxidation and reduction processes in DNA

    International Nuclear Information System (INIS)

    Hole, E.O.

    1992-01-01

    The papers presented in this thesis represent the major part of a systematic study of primary and secondary radiation induced damages in DNA. The magnetic resonance techniques EPR, ENDOR and FSE have been the experimental methods used. The study of radical formation in isolated DNA components under different environmental conditions demonstrates certain characteristics of the DNA components which are important in the study of DNA. It has been clearly demonstrated that the electrostatic environment, in particular the hydrogen bond pattern, is a vital factor for the secondary reaction scheme. Even radicals which are found in all related systems seem to be formed by different reaction pathways, depending upon the specific matrix. 92 refs., 2 figs., 6 tabs

  3. Monophosphate end groups produced in radiation induced strand breakage in DNA

    International Nuclear Information System (INIS)

    Kay, E.; Ward, J.F.

    1976-01-01

    A solution of DNA was gamma-irradiated and treated with monophosphatase for studies on the amount of inorganic phosphate released as a function of time. Studies were also conducted on: effect of alkali on yield of monophosphate end groups; induction of DNA strand breaks by treatment with DNAase; initial G values for monophosphate termini; and effect of alkali on radioinduced DNA damage

  4. Umbelliferone suppresses radiation induced DNA damage and apoptosis in hematopoietic cells of mice

    International Nuclear Information System (INIS)

    Jayakumar, S.; Bhilwade, H.N.; Chaubey, R.C.

    2012-01-01

    Radiotherapy is one of the major modes of treatment for different types of cancers. But the success of radiotherapy is limited by injury to the normal cells. Protection of the normal cells from radiation damage by radioprotectors can increase therapeutic efficiency. These radioprotectors can also be used during nuclear emergency situations. Umbelliferone (UMB) is a wide spread natural product of the coumarin family. It occurs in many plants from the Apiaceae family. In the present study radioprotective effect of UMB was investigated in vitro and in vivo. Anti genotoxic effect of Umbelliferone was tested by treating the splenic lymphocytes with various doses of UMB (6.5 μM - 50 μM) prior to radiation (6Gy) exposure. After the radiation exposure, extent of DNA damage was assessed by comet assay at 5 mm and two hours after radiation exposure. At both the time points, it was observed that the pretreatment of UMB reduced the radiation induced DNA damage to a significant extent in comparison to radiation control. UMB pretreatment also significantly reduced the radiation induced apoptosis enumerated by propidium iodide staining assay. Results of clonogenic survival assay using intestinal cell line showed that pretreatment with UMB significantly protected against radiation induced loss of colony forming units. To assess the anti genotoxic role of umbelliferone in vivo two different doses of UMB (20 mg/Kg and 40 mg/Kg of body weight) were injected into Swiss mice or with vehicle and exposed to radiation. Thirty minutes after the radiation comet assay was performed in peripheral leukocytes. Frequency of micro nucleated erythrocytes was scored in bone marrow cells. It was observed that UMB alone did not cause any significant increase in DNA damage in comparison to control. Animals which are exposed to radiation alone showed significant increase in DNA damage and micronuclei frequency. But animals treated with UMB prior to the radiation exposure showed significant decrease

  5. Normal formation and repair of γ-radiation-induced single and double strand DNA breaks in Down syndrome fibroblasts

    International Nuclear Information System (INIS)

    Steiner, M.E.; Woods, W.G.

    1982-01-01

    Fibroblasts from patients with Down syndrome (Trisomy 21) were examined for repair capability of γ-radiation-induced single strand and double strand DNA breaks. Formation and repair of DNA breaks were determined by DNA alkaline and non-denaturing elution techniques. Down syndrome fibroblasts were found to repair single strand and double strand breaks as well as fibroblasts from normal controls. (orig.)

  6. Carboplatin enhances the production and persistence of radiation-induced DNA single-strand breaks

    International Nuclear Information System (INIS)

    Yang, L.; Douple, E.B.; O'Hara, J.A.; Wang, H.J.

    1995-01-01

    Fluorometric analysis of DNA unwinding and alkaline elution were used to investigate the production and persistence of DNA single-strand breaks (SSBs) in Chinese hamster V79 and xrs-5 cells treated with the chemotherapeutic agent carboplatin in combination with radiation. Carboplatin was administered to cells before irradiation in hypoxic conditions, or the drug was added immediately after irradiation during the postirradiation recovery period in air. The results of DNA unwinding studies suggest that carboplatin enhances the production of radiation-induced SSBs in hypoxic V79 cells and xrs-5 cells by a factor of 1.86 and 1.83, respectively, when combined with radiation compared to the SSBs produced by irradiation alone. Carboplatin alone did not produce a measureable number of SSBs. Alkaline elution profiles also indicated that the rate of elution of SSBs was higher in cells treated with the carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs by a factor of 1.46 in V79 cells with 20 Gy irradiation and by a factor of 2.02 in xrs-5 cells with 20 Gy irradiation. When carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs is inhibited during this postirradiation incubation period (radiopotentiation) with a relative inhibition factor at 1 h postirradiation of 1.25 in V79 cells and 1.15 in xrs-5 cells. An increased production and persistence of SSBs resulting from the interaction of carboplatin with radiation may be an important step in the mechanism responsible for the potentiated cell killing previously from studies in animal tumors and in cultured cells. 31 refs., 7 figs

  7. Caffeine potentiates or protects against radiation-induced DNA and chromosomal damage in human lymphocytes depending on temperature and concentration

    International Nuclear Information System (INIS)

    Stoilov, L.M.; Mullenders, L.H.F.; Natarajan, A.T.

    1994-01-01

    The effect of caffeine on radiation-induced chromosomal aberrations and DNA strand breaks in unstimulated human lymphocytes was investigated. When present prior to and during the radiation exposure, caffeine treatment was found to cause either potentiation or protection against induction of chromosomal aberrations depending on the concentration and temperature. When the nucleoid sedimentation technique was applied, enhancement or reduction of radiation-induced DNA strand breaks by caffeine was also found to be dependent on temperature and caffeine concentration. It is proposed that caffeine, in addition to its suspected ability to influence DNA repair, can also influence the induction of DNA damage, leading to alterations in the yield of chromosomal aberrations

  8. Circular Mitochondrial DNA: A Geant4-DNA User Application for Evaluating Radiation-induced Damage in Circular Mitochondrial DNA.

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Moradi, Habiballah; Khanahmad, Hossein; Hosseini, Mohsen

    2017-01-01

    The aim of this study was to develop a nucleotide geometrical model of the circular mitochondrial DNA (mt-DNA) structure using Geant4-DNA toolkit to predict the radiation-induced damages such as single-strand breaks (SSB), double-strand breaks (DSB), and some other physical parameters. Our model covers the organization of a circular human mt genetic system. The current model includes all 16,659 base pairs of human mt-DNA. This new mt-DNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site-hit probabilities due to the impact of proton particles. The accuracy of the geometry was determined by three-dimensional visualization in various ring element numbers. The hit locations were determined with respect to a reference coordinate system, and the corresponding base pairs were stored in the ROOT output file. The coordinate determination according to the algorithm was consistent with the expected results. The output results contain the information about the energy transfers in the backbone region of the DNA double helix. The output file was analyzed by root analyzing tools. Estimation of SSBs and DSBs yielded similar results with the increment of incident particle linear energy transfer. In addition, these values seem to be consistent with the corresponding experimental determinations. This model can be used in numerical simulations of mt-DNA radiation interactions to perform realistic evaluations of DNA-free radical reactions. This work will be extended to supercoiled conformation in the near future.

  9. Nuclear aggregates of polyamines in a radiation-induced DNA damage model.

    Science.gov (United States)

    Iacomino, Giuseppe; Picariello, Gianluca; Stillitano, Ilaria; D'Agostino, Luciano

    2014-02-01

    Polyamines (PA) are believed to protect DNA minimizing the effect of radiation damage either by inducing DNA compaction and aggregation or acting as scavengers of free radicals. Using an in vitro pDNA double strand breakage assay based on gel electrophoretic mobility, we compared the protective capability of PA against γ-radiation with that of compounds generated by the supramolecular self-assembly of nuclear polyamines and phosphates, named Nuclear Aggregates of Polyamines (NAPs). Both unassembled PA and in vitro produced NAPs (ivNAPs) were ineffective in conferring pDNA protection at the sub-mM concentration. Single PA showed an appreciable protective effect only at high (mM) concentrations. However, concentrations of spermine (4+) within a critical range (0.481 mM) induced pDNA precipitation, an event that was not observed with NAPs-pDNA interaction. We conclude that the interaction of individual PA is ineffective to assure DNA protection, simultaneously preserving the flexibility and charge density of the double strand. Furthermore, data obtained by testing polyamine and ivNAPS with the current radiation-induced DNA damage model support the concept that PA-phosphate aggregates are the only forms through which PA interact with DNA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. The Role of DNA Methylation Changes in Radiation-Induced Bystander Effects in cranial irradiated Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Xue, Bei; Wang, Xinwen; Wang, Jiawen

    2016-07-01

    Heavy-ion radiation could lead to bystander effect in neighboring non-hit cells by signals released from directly-irradiated cells. The exact mechanisms of radiation-induced bystander effect in distant organ remain obscure, yet accumulating evidence points to the role of DNA methylation changes in bystander effect. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male Balb/c and C57BL mice were cranial exposed to 40, 200, 2000mGy dose of carbon heavy-ion radiation, while the rest of the animal body was shielded. The γH2AX foci as the DNA damage biomarker in directly irradiation organ ear and the distant organ liver were detected on 0, 1, 2, 6, 12 and 24h after radiation, respectively. Methylation-sensitive amplifcation polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that cranial irradiated mice could induce the γH2AX foci and genomic DNA methylation changes significantly in both the directly irradiation organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate were highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation in ear. The global DNA methylation changes tended to occur in the CG sites. We also found that the numbers of γH2AX foci and the genomic methylation changes of heavy-ion radiation-induced bystander effect in liver could be obvious 1 h after radiation and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in both directly radiation organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of radiation induced bystander effects in vivo. Keywords: Heavy-ion radiation; Bystander effect; DNA methylation; γH2

  11. Role of extracellular DNA oxidative modification in radiation induced bystander effects in human endotheliocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kostyuk, Svetlana V. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Alekseeva, Anna Yu.; Smirnova, Tatiana D.; Glebova, Kristina V.; Efremova, Liudmila V. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Baranova, Ancha [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); School of System Biology, George Mason University, Fairfax, VA 22030 (United States); Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2012-01-03

    The development of the bystander effect induced by low doses of irradiation in human umbilical vein endothelial cells (HUVECs) depends on extracellular DNA (ecDNA) signaling pathway. We found that the changes in the levels of ROS and NO production by human endothelial cells are components of the radiation induced bystander effect that can be registered at a low dose. We exposed HUVECs to X-ray radiation and studied effects of ecDNA{sup R} isolated from the culture media conditioned by the short-term incubation of irradiated cells on intact HUVECs. Effects of ecDNA{sup R} produced by irradiated cells on ROS and NO production in non-irradiated HUVECs are similar to bystander effect. These effects at least partially depend on TLR9 signaling. We compared the production of the nitric oxide and the ROS in human endothelial cells that were (1) irradiated at a low dose; (2) exposed to the ecDNA{sup R} extracted from the media conditioned by irradiated cells; and (3) exposed to human DNA oxidized in vitro. We found that the cellular responses to all three stimuli described above are essentially similar. We conclude that irradiation-related oxidation of the ecDNA is an important component of the ecDNA-mediated bystander effect.

  12. Radioprotective potential of Decalepis hamiltonii: a study on gamma radiation-induced oxidative stress and toxicity in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Pasha, Muzeer; Shivanandappa, T.; Ramesh, S.R.; Sanjeev, Ganesh

    2016-01-01

    Radiation-induced damage to normal tissues restricts the therapeutic use of radiation in clinical application for cancer treatment and thereby limits the efficacy of the treatment. The use of chemical compounds as radioprotectors is a desirable strategy to improve the therapeutic index of radiotherapy. However, most of the synthetic radioprotective compounds studied have shown to have undesirable properties of toxicity. There is a need for safer, natural radioprotective agents without compromising efficacy of the treatment. We have investigated the radioprotective potential of Decalepis hamiltonii (Dh) root extract which is rich in natural antioxidants by employing Drosophila melanogaster as a model. Irradiation of Drosophila with 100, 200, and 400 Gy of gamma radiation induced dose-dependent mortality. Elevation in the levels of thiobarbituric acid reactive substances (TBARS), the activities of catalase (CAT) and superoxide dismutase (SOD), and depletion of glutathione (GSH) content suggested radiation-induced oxidative stress. Pretreatment of flies with Dh root extract protected them from radiation-induced mortality and oxidative stress as evidenced by reduction in TBARS and restoration of the antioxidant enzymes, SOD and CAT, and GSH to control levels. This is the first report of radioprotective action of Dh root extract in D. melanogaster. (author)

  13. Study of the potential effect of selenium on gamma-radiation induced ovarian failure

    International Nuclear Information System (INIS)

    Said, R.S.M.

    2012-01-01

    Radiotherapy is a major factor contributing to female infertility by inducing premature ovarian failure (POF). Therefore, the need for an effective radioprotective agent is evident. The present study investigated the mechanism of potential radioprotective effect of sodium selenite on radiation-induced ovarian failure and whether sodium selenite can stimulate in vivo follicular development in experimental rats. Immature female Sprague-Dawely rats were either exposed to gamma radiation (3.2 Gy, LD 20 ), once and/or treated with sodium selenite (0.5 mg/kg), once daily for one week before irradiation. Follicular and oocyte development, apoptotic markers, proliferation marker as well as oxidative stress markers were assessed 24-h after irradiation. In addition, fertility assessment was performed after female rats became completely mature at two months of age. Sodium selenite significantly enhanced follicular development as compared to the irradiated group. Sodium selenite significantly reversed the oxidative stress effects of radiation that was evidenced by increasing in lipid peroxide level and decreasing in glutathione level, and glutathione peroxidase (GPx) activity. Assessment of apoptosis and cell proliferation markers revealed that caspase 3 and cytochrome c expressions markedly-increased, whereas, PCNA expression markedly-decreased in the irradiated group; in contrast, sodium selenite treatment prevented these alterations. Histopathological examination further confirmed the radioprotective efficacy of sodium selenite and its in-vivo effect on ovarian follicles’ maturation. In conclusion, sodium selenite showed a radioprotective effect and improved folliculogenesis through increasing ovarian granulosa cells proliferation, estradiol and FSH secretion, and GPx activity, whilst decreasing lipid peroxidation and oxidative stress, leading to inhibition of the apoptosis pathway through decreasing the expressions of caspase 3 and cytochrome c.

  14. Effects of hyperthermia on repair of radiation-induced DNA strand breaks

    International Nuclear Information System (INIS)

    Mills, M.D.; Meyn, R.E.

    1981-01-01

    Previous reports have suggested a relationship between the heat-induced changes in nucleoprotein and the hyperthermic enhancement of radiation sensitivity. In an effort to further understand these relationships, we measured the level of initial DNA strand break damage and the DNA strand break rejoining kinetics in Chinese hamster ovary cells following combined hyperthermia and ionizing radiation treatments. The amount of protein associated with DNA measured as the ratio of [ 3 H)leucine to [ 14 C]thymidine was also compared in chromatin isolated from both heated and unheated cells. The results of these experiments show that the initial level of radiation-induced DNA strand breaks is significantly enhanced by a prior hyperthermia treatment of 43 0 C for 30 min. Treatments at higher temperatures and longer treatments at the same temperature magnified this effect. Hyperthermia was also shown to cause a substantial inhibition of the DNA strand break rejoining after irradiation. Both the initial level of DNA damage and the rejoining kinetics recovered to normal levels with incubation at 37 0 C between the hyperthermia and radiation treatments. Recovery of these parameters coincided with the return of the amount of protein associated with DNA to normal values, further suggesting a relationship between the changes in nucleoprotein and the hyperthermic enhancement of radiation sensivivity

  15. Gamma ray radiation induced visible light absorption in P-doped silica fibers at low dose levels

    CERN Document Server

    Lu Ping; Kulkarni, N S; Brown, K

    1999-01-01

    A CCD Fiber Optic Spectrometer has been used to monitor the gamma ray radiation induced loss in P-doped fibers at different dopant concentrations (1, 5 and 10 mol%) with a light source (an incandescent bulb with a temperature of 2800-3000 K). The range of dose rates is limited to that used in medical applications (cancer treatments), that is 0.1 to 1.0 Gray per minute (Gy/min). At low integral dose level (<2.0 Gy) four absorption peaks were observed (470, 502, 540 and 600 nm) within the visible region. It has been observed that the radiation induced loss at 470 and 600 nm depends strongly on dose rate. At dose rates of 0.2 and 0.5 Gy/min the induced loss shows nonlinear relation to the total dose. However, at high dose rate (1.0 Gy/min) and low dose rate (0.1 Gy/min) it seems to have a linear dependence with total dose. The conversion from NBOHCs to GeX centers was observed during gamma radiation at low dose rates (0.1-0.5 Gy/min). At the wavelength of 502 and 540 nm, the radiation induced losses show exce...

  16. Spatiotemporal characterization of ionizing radiation induced DNA damage foci and their relation to chromatin organization

    Energy Technology Data Exchange (ETDEWEB)

    Costes, Sylvain V; Chiolo, Irene; Pluth, Janice M.; Barcellos-Hoff, Mary Helen; Jakob, Burkhard

    2009-09-15

    DNA damage sensing proteins have been shown to localize to the sites of DSB within seconds to minutes following ionizing radiation (IR) exposure, resulting in the formation of microscopically visible nuclear domains referred to as radiation-induced foci (RIF). This review characterizes the spatio-temporal properties of RIF at physiological doses, minutes to hours following exposure to ionizing radiation, and it proposes a model describing RIF formation and resolution as a function of radiation quality and nuclear densities. Discussion is limited to RIF formed by three interrelated proteins ATM (Ataxia telangiectasia mutated), 53BP1 (p53 binding protein 1) and ?H2AX (phosphorylated variant histone H2AX). Early post-IR, we propose that RIF mark chromatin reorganization, leading to a local nuclear scaffold rigid enough to keep broken DNA from diffusing away, but open enough to allow the repair machinery. We review data indicating clear kinetic and physical differences between RIF emerging from dense and uncondensed regions of the nucleus. At later time post-IR, we propose that persistent RIF observed days following exposure to ionizing radiation are nuclear ?scars? marking permanent disruption of the chromatin architecture. When DNA damage is resolved, such chromatin modifications should not necessarily lead to growth arrest and it has been shown that persistent RIF can replicate during mitosis. Thus, heritable persistent RIF spanning over tens of Mbp may affect the transcriptome of a large progeny of cells. This opens the door for a non DNA mutation-based mechanism of radiation-induced phenotypes.

  17. Solar ultraviolet radiation-induced DNA damage in aquatic organisms: potential environmental impact

    International Nuclear Information System (INIS)

    Haeder, Donat-P.; Sinha, Rajeshwar P.

    2005-01-01

    Continuing depletion of stratospheric ozone and subsequent increases in deleterious ultraviolet (UV) radiation at the Earth's surface have fueled the interest in its ecological consequences for aquatic ecosystems. The DNA is certainly one of the key targets for UV-induced damage in a variety of aquatic organisms. UV radiation induces two of the most abundant mutagenic and cytotoxic DNA lesions, cyclobutane pyrimidine dimers (CPDs) and pyrimidine pyrimidone photoproducts (6-4PPs) and their Dewar valence isomers. However, aquatic organisms have developed a number of repair and tolerance mechanisms to counteract the damaging effects of UV on DNA. Photoreactivation with the help of the enzyme photolyase is one of the most important and frequently occurring repair mechanisms in a variety of organisms. Excision repair, which can be distinguished into base excision repair (BER) and nucleotide excision repair (NER), also play an important role in DNA repair in several organisms with the help of a number of glycosylases and polymerases, respectively. In addition, mechanisms such as mutagenic repair or dimer bypass, recombinational repair, cell-cycle checkpoints, apoptosis and certain alternative repair pathways are also operative in various organisms. This review deals with the UV-induced DNA damage and repair in a number of aquatic organisms as well as methods of detecting DNA damage

  18. Complex DNA Damage: A Route to Radiation-Induced Genomic Instability and Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Ifigeneia V. Mavragani

    2017-07-01

    Full Text Available Cellular effects of ionizing radiation (IR are of great variety and level, but they are mainly damaging since radiation can perturb all important components of the cell, from the membrane to the nucleus, due to alteration of different biological molecules ranging from lipids to proteins or DNA. Regarding DNA damage, which is the main focus of this review, as well as its repair, all current knowledge indicates that IR-induced DNA damage is always more complex than the corresponding endogenous damage resulting from endogenous oxidative stress. Specifically, it is expected that IR will create clusters of damage comprised of a diversity of DNA lesions like double strand breaks (DSBs, single strand breaks (SSBs and base lesions within a short DNA region of up to 15–20 bp. Recent data from our groups and others support two main notions, that these damaged clusters are: (1 repair resistant, increasing genomic instability (GI and malignant transformation and (2 can be considered as persistent “danger” signals promoting chronic inflammation and immune response, causing detrimental effects to the organism (like radiation toxicity. Last but not least, the paradigm shift for the role of radiation-induced systemic effects is also incorporated in this picture of IR-effects and consequences of complex DNA damage induction and its erroneous repair.

  19. Protection of radiation induced DNA and membrane damages by total triterpenes isolated from Ganoderma lucidum (Fr.) P. Karst.

    Science.gov (United States)

    Smina, T P; Maurya, D K; Devasagayam, T P A; Janardhanan, K K

    2015-05-25

    The total triterpenes isolated from the fruiting bodies of Ganoderma lucidum was examined for its potential to prevent γ-radiation induced membrane damage in rat liver mitochondria and microsomes. The effects of total triterpenes on γ-radiation-induced DNA strand breaks in pBR 322 plasmid DNA in vitro and human peripheral blood lymphocytes ex vivo were evaluated. The protective effect of total triterpenes against γ-radiation-induced micronuclei formations in mice bone marrow cells in vivo were also evaluated. The results indicated the significant effectiveness of Ganoderma triterpenes in protecting the DNA and membrane damages consequent to the hazardous effects of radiation. The findings suggest the potential use of Ganoderma triterpenes in radio therapy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Possible Protective Effect of Aqueous Extract of Moringa oleifera Lam. on Gamma Radiation Induced-Oxidative Stress in Rats

    International Nuclear Information System (INIS)

    Abd El-Azime, A.Sh.; Kamal El-Dein, E.M.

    2014-01-01

    Medicinal herbs are used in indigenous system of medicine for various diseases. Moringa oleifera (M. oleifera) has a high medicinal value which has been recognized. The present study was designed to evaluate the protective effect of aqueous extract of M. oleifera leaves against whole body gamma radiation-induced toxicity in rats. Rats received orally by gavage the aqueous extract of M. oleifera leaves 300 mg/Kg body weight/day for 40 days and rats subjected to whole body gamma-irradiation at a dose of 5 Gy delivered as single exposure dose at day 35 of M. oleifera treatment rats and sacrificed at 5th day after irradiation. The results obtained showed that exposure to gamma radiation provoked a significant increase in serum gamma-glutamyl transpeptidase (γ-GT), alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP), glucose, total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and very low density lipoprotein cholesterol (vLDL-C) level. While high density lipoprotein cholesterol (HDL-C) and insulin level showed a significant decrease. Moreover a significant decrease of glutathione (GSH) content, superoxide dismutase (SOD) and catalase (CAT) activities associated to a significant increase of thiobarbituric acid reactive substances (TBARS) were recorded in blood and liver of rats. Treatment with M. oleifera significantly reduced the radiation-induced serum and liver biochemical disorders which was associated with a significant amelioration in antioxidant status in both liver and serum. The results indicated that M. oleifera might protect from radiation induced damage due to its ability to scavenge free radicals

  1. Effect of aqueous extract of saffron (crocus sativus L.) against gamma radiation-induced skeletal muscles damage in rats

    International Nuclear Information System (INIS)

    El-Tahawy, N.A; Said, U.Z

    2010-01-01

    Muscular strength is important in sport as well as in daily activities. Reactive oxygen species (ROS) and oxidative damage are the most important factors in radiation-induced acute damage to muscle tissue. Saffron, obtained from dried stigmas of Crocus sativus L. (Iridaceae), is a highly valued spice, commonly used in flavouring and food colouring in different parts of the world and is known to possess the richest source of carotenoids. The present study was designed to investigate the efficacy of an aqueous extract of saffron to protect against radiation-induced oxidative damage in rat's skeletal muscle. Saffron was supplemented orally, via gavages to rats at a dose of 80 mg/ kg body wt/ day for 2 week pre- and 1 week post-exposure to 5 Gy (one shot dose) of whole body gamma-irradiation. Animals were sacrificed 1, 2 and 3 weeks post radiation exposure. The results revealed that whole body gamma-irradiation of rats induce oxidative stress in skeletal muscles obvious by significant elevation in the level of thiobarbituric acid reactive substances associated with significant decreases in superoxide dismutase and catalase activities. Also, radiation-induces skeletal muscles damage evidenced by significant decreases in the level of pyruvic acid, creatine phosphokinase, glutamate dehydrogenase and glucose-6-phosphate dehydrogenase activities as well as significant increases in lactic acid, total iron, and copper and calcium levels. Saffron treated-irradiated rats showed significantly less severe damage and remarkable improvement in all the measured parameters, compared to irradiated rats. It could be concluded that saffron by attenuating radiation-induced oxidative stress might play a role in maintaining skeletal muscle integrity.

  2. Radiation-induced changes in DNA methylation of repetitive elements in the mouse heart

    Energy Technology Data Exchange (ETDEWEB)

    Koturbash, Igor, E-mail: ikoturbash@uams.edu [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Miousse, Isabelle R. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Sridharan, Vijayalakshmi [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Nzabarushimana, Etienne; Skinner, Charles M. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Melnyk, Stepan B.; Pavliv, Oleksandra [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Hauer-Jensen, Martin [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205 (United States); Nelson, Gregory A. [Departments of Basic Sciences and Radiation Medicine, Loma Linda University, Loma Linda, CA 92354 (United States); Boerma, Marjan [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States)

    2016-05-15

    Highlights: • Radiation-induced dynamic changes in cardiac DNA methylation were detected. • Early LINE-1 hypomethylation was followed by hypermethylation at a later time-point. • Radiation affected one-carbon metabolism in the heart tissue. • Irradiation resulted in accumulation of satellite DNA mRNA transcripts. - Abstract: DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation—proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ({sup 56}Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or {sup 56}Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with {sup 56}Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and

  3. [Ionizing radiation-induced DNA damage and its repair in human cells]. Progress report, [April 1, 1993--February 28, 1994

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The excision of radiation-induced lesions in DNA by a DNA repair enzyme complex, namely the UvrABC nuclease complex, has been investigated. Irradiated DNA was treated with the enzyme complex. DNA fractions were analyzed by gas chromatography/isotope-dilution mass spectrometry. The results showed that a number pyrimidine- and purine-derived lesions in DNA were excised by the UvrABC nuclease complex and that the enzyme complex does not act on radiation-induced DNA lesions as a glycosylase. This means that it does not excise individual base products, but it excises oligomers containing these lesions. A number of pyrimidine-derived lesions that were no substrates for other DNA repair enzymes investigated in our laboratory were substrates for the UvrABC nuclease complex.

  4. Inhibition of radiation-induced DNA strand breaks by hoechst 33258: OH-radical scavenging and DNA radical quenching

    International Nuclear Information System (INIS)

    Adhikary, A.; Bothe, E.; Von Sonntag, C.; Adhikary, A.

    1997-01-01

    The minor-groove-binding dye Hoechst 33258 has been found to protect pBR322 DNA in aqueous solution against radiation-induced single-strand breaks (ssb). This protective effect has been assumed to be largely due to the scavenging of the strand-break-generating OH radicals by Hoechst. From D 37 values for ssb at different Hoechst concentrations the value of the OH radical scavenging constant of DNA-bound Hoechst has been estimated at k Ho/DNA = 2.7 * 10 11 dm 3 mol -1 . This unexpectedly high value has led us to study the reactions of OH radicals with Hoechst in the absence and in the presence of double-stranded calf thymus DNA (ds DNA) by pulse radiolysis, and the formation of radiation-induced ssb by low angle laser light scattering. The D 37 /D 37 0 values at different Hoechst concentrations agree with the values obtained by Martin and al. and demonstrate the protection. However, this protection cannot be explained on the basis of OH radical scavenging alone using the above rate constants. There must, in addition, be some quenching of DNA radicals. Hoechst radicals are formed in the later ms time range, i.e a long time after the disappearance of the OH radicals. This delayed Hoechst radical formation has been assigned to a a reaction of DNA radicals with Hoechst, thereby inhibiting strand breakage. In confirmation, pulse radiolysis of aqueous solution of nucleotides in the presence of Hoechst yields a similar delayed Hoechst radical formation. The data indicate that in DNA the cross-section of this quenching has a diameter of 3 to 4 base pairs per Hoechst molecule. (N.C.)

  5. Ferulic acid (FA) abrogates γ-radiation induced oxidative stress and DNA damage by up-regulating nuclear translocation of Nrf2 and activation of NHEJ pathway.

    Science.gov (United States)

    Das, Ujjal; Manna, Krishnendu; Khan, Amitava; Sinha, Mahuya; Biswas, Sushobhan; Sengupta, Aaveri; Chakraborty, Anindita; Dey, Sanjit

    2017-01-01

    The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50 mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10 Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process.

  6. Influence of the complexity of radiation-induced DNA damage on enzyme recognition

    International Nuclear Information System (INIS)

    Palmer, Philip

    2002-01-01

    Ionising radiation is unique in inducing DNA clustered damage together with the simple isolated lesions. Understanding how these complex lesions are recognised and repaired by the cell is key to understanding the health risks associated with radiation exposure. This study focuses on whether ionising radiation-induced complex single-strand breaks (SSB) are recognised by DNA-PK and PARP, and whether the complexity of DSB influence their ligation by either DNA ligase lV/XRCC4 (LX) complex or T4 DNA ligase. Plasmid DNA, irradiated in aqueous solution using sparsely ionising γ-rays and densely ionising α-particles produce different yields of complex DNA damages, used as substrates for in vitro DNA-PK and PARP activity assays. The activity of DNA-PK to phosphorylate a peptide was determined using HF19 cell nuclear extracts as a source of DNA-PK. PARP ADP-ribosylation activity was determined using purified PARP enzyme. The activation of DNA-PK and PARP by irradiated DNA is due to SSB and not the low yield of DSB (linear plasmid DNA <10%). A ∼2 fold increase in DNA-PK activation and a ∼3-fold reduction in PARP activity seen on increasing the ionising density of the radiation (proportion of complex damage) are proposed to reflect changes in the complexity of SSB and may relate to damage signalling. Complex DSB synthesised as double-stranded oligonucleotides, with a 2 bp 5'-overhang, and containing modified lesions, 8-oxoguanine and abasic sites, at known positions relative to the termini were used as substrates for in vitro ligation by DNA ligase IV/XRCC4 or T4 ligase. The presence of a modified lesion 2 or 3 bp but not 4 bp from the 3'-termini and 2 or 6 bp from the 5'-termini caused a drastic reduction in the extent of ligation. Therefore, the presence of modified lesions near to the termini of a DSB may compromise their rejoining by non-homologous end-joining (NHEJ) involving the LX complex. (author)

  7. The Effect of a Grape Seed Extract on Radiation-Induced DNA Damage in Human Lymphocytes

    Science.gov (United States)

    Dicu, Tiberius; Postescu, Ion D.; Foriş, Vasile; Brie, Ioana; Fischer-Fodor, Eva; Cernea, Valentin; Moldovan, Mircea; Cosma, Constantin

    2009-05-01

    Plant-derived antioxidants due to their phenolic compounds content are reported as potential candidates for reducing the levels of oxidative stress in living organisms. Grape seed extracts are very potent antioxidants and exhibit numerous interesting pharmacologic activities. Hydroethanolic (50/50, v/v) standardized extract was obtained from red grape seed (Vitis vinifera, variety Burgund Mare—BM). The total polyphenols content was evaluated by Folin-Ciocalteu procedure and expressed as μEq Gallic Acid/ml. The aim of this study was to evaluate the potential antioxidant effects of different concentrations of BM extract against 60Co γ-rays induced DNA damage in human lymphocytes. Samples of human lymphocytes were incubated with BM extract (12.5, 25.0 and 37.5 μEq GA/ml, respectively) administered at 30 minutes before in vitro irradiation with γ-rays (2 Gy). The DNA damage and repair in lymphocytes were evaluated using alkaline comet assay. Using the lesion score, the radiation-induced DNA damage was found to be significantly different (pextract (except the lymphocytes treated with 37.5 μEq GA/ml BM extract). DNA repair analyzed by incubating the irradiated cells at 37° C and 5% CO2 atmosphere for 2 h, indicated a significant difference (pextract, immediately and two hours after irradiation. These results suggest radioprotective effects after treatment with BM extract in human lymphocytes.

  8. The use of recombinant DNA techniques to study radiation-induced damage, repair and genetic change in mammalian cells

    International Nuclear Information System (INIS)

    Thacker, J.

    1986-01-01

    A brief introduction is given to appropriate elements of recombinant DNA techniques and applications to problems in radiobiology are reviewed with illustrative detail. Examples are included of studies with both 254 nm ultraviolet light and ionizing radiation and the review progresses from the molecular analysis of DNA damage in vitro through to the nature of consequent cellular responses. The review is dealt with under the following headings: Molecular distribution of DNA damage, The use of DNA-mediated gene transfer to assess damage and repair, The DNA double strand break: use of restriction endonucleases to model radiation damage, Identification and cloning of DNA repair genes, Analysis of radiation-induced genetic change. (UK)

  9. Detection, characterization and measure of a new radiation-induced damage in isolated and cellular DNA

    International Nuclear Information System (INIS)

    Regulus, P.

    2006-10-01

    Deoxyribonucleic acid (DNA) contains the genetic information and chemical injury to this macromolecule may have severe biological consequences. We report here the detection of 4 new radiation-induced DNA lesions by using a high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) approach. For that purpose, the characteristic fragmentation of most 2'-deoxy-ribo nucleosides, the loss of 116 Da corresponding to the loss of the 2-deoxyribose moiety, was used in the so-called neutral loss mode of the HPLC-MS/MS. One of the newly detected lesions, named dCyd341 because it is a 2'-deoxycytidine modification exhibiting a molecular weight of 341 Da, was also detected in cellular DNA. Characterization of this modified nucleoside was performed using NMR and exact mass determination of the product obtained by chemical synthesis. A mechanism of formation was then proposed, in which the first event is the H-abstraction at the C4 position of a 2-deoxyribose moiety. Then, the sugar modification produced exhibits a reactive aldehyde that, through reaction with a vicinal cytosine base, gives rise to dCyd341. dCyd341 could be considered as a complex damage since its formation involves a DNA strand break and a cross-link between a damaged sugar residue and a vicinal cytosine base located most probably on the complementary DNA strand. In addition to its characterization, preliminary biological studies revealed that cells are able to remove the lesion from DNA. Repair studies have revealed the ability of cells to excise the lesion. Identification of the repair systems involved could represent an interesting challenge. (author)

  10. Grape (Vitis vinifera) extracts protect against radiation-induced oxidative stress and DNA damage

    International Nuclear Information System (INIS)

    Singha, Indrani; Das, Subir Kumar; Saxena, S.; Gautam, S.

    2016-01-01

    Ionizing radiation (IR) causes oxidative stress through the overwhelming generation of reactive oxygen species (ROS) in the living cells leading further to the oxidative damage to biomolecules. Grapes (Vitis vinifera) contain several bioactive phytochemicals and are the richest source of antioxidant. In this study, we investigated and compared in vitro antioxidant activity and DNA damage protective property of the grape extracts of four different cultivars, including the Thompson seedless, Flame seedless, Kishmish chorni and Red globe. The activities of ascorbic acid oxidase and catalase significantly (p<0.01) differed among extracts within the same cultivar, while that of peroxidase and polyphenol oxidase did not differ significantly among extracts of any cultivar. In vitro antioxidant activities were assessed by ferric-reducing antioxidant power (FRAP) assay and ABTS. The superoxide radical-scavenging activity was higher in the seed as compared to the skin or pulp of the same cultivar. DNA damage was evaluated in acellular system using pBR322 plasmid relaxation. Grape extract was able to effectively scavenge free radicals in vitro. It could significantly prevent radiation-induced DNA damage. Furthermore, the protective action of grape depends on the source of extract and type of the cultivars. (author)

  11. Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

    Energy Technology Data Exchange (ETDEWEB)

    Stenerl& #246; w, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn; Stenerlow, Bo

    2008-04-29

    Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation of genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy in the initial DSB yield. These heat-released DSBs were repaired within 60-90 min in all tested cells, including M059K cells treated with wortmannin or DNA-PKcs defect M059J cells. Furthermore, cells lacking XRCC1 or Poly(ADP-ribose) polymerase-1 (PARP-1) rejoined both total DSBs and heat-released DSBs similar to normal cells. In summary, the presence of heat-labile sites have a substantial impact on DSB induction yields and DSB rejoining rates measured by pulsed-field gel electrophoresis, and HLS repair is independent of DNA-PKcs, XRCC1 and PARP.

  12. The cellular environment in computer simulations of radiation-induced damage to DNA

    International Nuclear Information System (INIS)

    Moiseenko, V.V.; Hamm, R.N.; Waker, A.J.; Prestwich, W.V.

    1988-01-01

    Radiation-induced DNA single- and double-strand breaks were modeled for 660 keV photon radiation and scavenger capacity mimicking the cellular environment. Atomistic representation of DNA in B form with a first hydration shell was utilized to model direct and indirect damage. Monte Carlo generated electron tracks were used to model energy deposition in matter and to derive initial spatial distributions of species which appear in the medium following radiolysis. Diffusion of species was followed with time, and their reactions with DNA and each other were modeled in an encounter-controlled manner. Three methods to account for hydroxyl radical diffusion in cellular environment were tested: assumed exponential survival, time-limited modeling and modeling of reactions between hydroxyl radicals and scavengers in an encounter-controlled manner. Although the method based on modeling scavenging in an encounter-controlled manner is more precise, it requires substantially more computer resources than either the exponential or time-limiting method. Scavenger concentrations of 0.5 and 0.15 M were considered using exponential and encounter-controlled methods with reaction rate set at 3x10 9 dm 3 mol -1 s-1. Diffusion length and strand break yields, predicted by these two methods for the same scavenger molarity, were different by 20%-30%. The method based on limiting time of chemistry follow-up to 10 -9 s leads to DNA damage and radical diffusion estimates similar to 0.5 M scavenger concentration in the other two methods. The difference observed in predictions made by the methods considered could be tolerated in computer simulations of DNA damage. (author)

  13. Gamma radiation induced mutagenesis of lysobacter enzymogenes for enhanced chitinolytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Kim, Kyoung Youl; Senthilkumar, M. [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-03-15

    Two chitinase producing strains CHI2 and CHI4 were isolated from soybean rhizosphere soil. Both the strains belonged to Lysobacter enzymogenes as indicated by 16S rDNA sequence analysis. Though strain CHI2 and CHI4 produced extracellular chitinase, they differ in their chitinolytic activity. CHI4 produced approximately three times the higher amounts of enzyme than that of CHI2 under specified conditions. CHI2 produced 535.67 U I{sup -1} of chitinase after 48 h incubation with a specific activity of 3.91 U mg{sup -1} of protein while strain CHI4 produced 1584.13 U I{sup -1} of chitinase with a specific activity of 10.88 U mg{sup -1} protein. SDS-PAGE analysis indicated that the molecular weight of chitinase enzyme was approximately 45 kDa. A faint band with a molecular weight of 55 kDa reveals the possibility for the isolates to gamma rays at their LD{sub 99} value (0.23 kGy). Totally, 11 mutants of CHI2 and CHI4 are reported to have enhanced chitinase activity. Several leaky mutant clones with decreased enzyme activity and a defective mutant (CHI2-M16) with complete loss of chitinase activity were also dentified. CHI4-M18, CHI4-M8 and CHI4-M29 showed 78.8, 41.5, and 31.9% increased chitinase activity over type CHI4.

  14. Effect of Pre-Gamma Irradiation Induction of Metallothionein on potentially Radiation-Induced Toxic Heavy Metals Ions In Rats

    International Nuclear Information System (INIS)

    El-Shamy, El.

    2004-01-01

    Metallothionein, which is a cystein-rich metal binding protein, can act as free radical scavenger and involved in resistance to heavy metal toxicity. The induction of synthesis has been shown to protect organs from the toxic effect of radiation. This study aimed to stud the effects of pre-irradiation induction of by heavy metal (Zinc sulfate) on potentially gamma radiation-induced toxic heavy metals ions in rate liver and kidney tissues. Forty eight albino rats were included in this study. They were divided into eight groups each of six animals. Two control groups injected with saline. Two Zinc sulfate-treated groups injected with zinc sulfate, two Irradiated groups exposed to a single dose level (7 Gy) of whole body gamma irradiation and two combined zinc sulfate and irradiation groups injected with zinc sulfate and exposed to whole body gamma irradiation (at dose 7 Gy). Animals of all groups were sacrificed 24 and 48 hours after last either zinc sulfate dose or irradiation. Samples of liver and kidney's tissues were subjected to the following investigations: Estimation of tissue heavy Metals (Zinc, Iron and Copper), and tissue (MT). After irradiation, liver and kidney MT were increased approximately 10-fold and 2-fold respectively after irradiation. Accumulation of zinc and iron in both liver and kidney tissues were detected, while accumulation of copper only in the liver tissues. The pre-irradiation treatment with zinc sulfate (Zn SO4) resulted in highly significant decrease in zinc, iron, and copper levels in both liver and kidney tissues in comparison with irradiation groups. Conclusion, it can be supposed that pre-irradiation injection of ZnSO 4 exerted protective effect against the potentially radiation-induced toxic heavy metals ions through MT induction

  15. Low intensity microwave radiation induced oxidative stress, inflammatory response and DNA damage in rat brain.

    Science.gov (United States)

    Megha, Kanu; Deshmukh, Pravin Suryakantrao; Banerjee, Basu Dev; Tripathi, Ashok Kumar; Ahmed, Rafat; Abegaonkar, Mahesh Pandurang

    2015-12-01

    Over the past decade people have been constantly exposed to microwave radiation mainly from wireless communication devices used in day to day life. Therefore, the concerns over potential adverse effects of microwave radiation on human health are increasing. Until now no study has been proposed to investigate the underlying causes of genotoxic effects induced by low intensity microwave exposure. Thus, the present study was undertaken to determine the influence of low intensity microwave radiation on oxidative stress, inflammatory response and DNA damage in rat brain. The study was carried out on 24 male Fischer 344 rats, randomly divided into four groups (n=6 in each group): group I consisted of sham exposed (control) rats, group II-IV consisted of rats exposed to microwave radiation at frequencies 900, 1800 and 2450 MHz, specific absorption rates (SARs) 0.59, 0.58 and 0.66 mW/kg, respectively in gigahertz transverse electromagnetic (GTEM) cell for 60 days (2h/day, 5 days/week). Rats were sacrificed and decapitated to isolate hippocampus at the end of the exposure duration. Low intensity microwave exposure resulted in a frequency dependent significant increase in oxidative stress markers viz. malondialdehyde (MDA), protein carbonyl (PCO) and catalase (CAT) in microwave exposed groups in comparison to sham exposed group (pmicrowave exposed groups (pmicrowave exposed animal (pmicrowave exposed groups as compared to their corresponding values in sham exposed group (pmicrowave radiation induces oxidative stress, inflammatory response and DNA damage in brain by exerting a frequency dependent effect. The study also indicates that increased oxidative stress and inflammatory response might be the factors involved in DNA damage following low intensity microwave exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Palliative effects of lutein intervention in gamma-radiation-induced cellular damages in Swiss albino mice.

    Science.gov (United States)

    Vasudeva, Vidya; Tenkanidiyoor, Yogish Somayaji; Radhakrishna, Vishakh; Shivappa, Pooja; Lakshman, Srikanth Patil; Fernandes, Ronald; Patali, Krishna Ananthapura

    2017-01-01

    Radiation-induced hematological, biochemical, and cytogenetic damages to the normal cells are major concerns in the field of radiotherapy. The carotenoids and their derivatives have been the source of antioxidants with wide range of medicinal applications. The objective is to evaluate the protective effects of lutein, a carotenoid, against radiation-induced cellular and tissue damages. Swiss albino mice were grouped into 5, 50, 250, and 500 mg/kg b.wt. of lutein treatment groups, a sham and vehicle control group. The groups were irradiated with a lethal dose of 10 Gy y'-radiation. The mortality was recorded for 30 days to optimize the protective dose against radiation. The mice were administered with the compound orally for 15 consecutive days and irradiated with a sublethal dose of 6Gy. The hematological changes in blood and antioxidant parameters were determined in liver, kidney homogenates, and hemolysate/serum. The hematological parameters were recorded using an automated cell counter. The antioxidants such as malondialdehyde (MDA), glutathione (GSH), superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase were spectrophotometrically determined. The red blood cell, white blood cell count, lymphocyte count, hemoglobin, platelet levels, and hematocrit value were found to be decreased in the irradiated groups. Lutein pretreatment maintains near-normal levels of these parameters indicating resistance/recovery from the radiation-induced damages. The antioxidant levels were found to be reduced in all the irradiated groups. However, lutein pretreatment (50 mg/kg b.wt.) has increased the catalase activity of hemolysate. Lutein pretreatment has reduced the MDA levels in hemolysate, when administered at doses of 5, 250, and 500 mg/kg b.wt. in comparison to its control. The study demonstrates the radioprotective potential of lutein by maintaining the hematological and antioxidant homeostasis.

  17. Glutathione requirement for the rejoining of radiation-induced DNA breaks in misonidazole-treated cells

    International Nuclear Information System (INIS)

    Edgren, M.; Revesz, L.

    1985-01-01

    The role of glutathione (GSH) in the rejoining of radiation-induced single-strand DNA breaks (ssb) was studied in human fibroblast cultures sensitized to radiation by a 30 min treatment with 1 mM misonidazole (MISO). Hypoxically irradiated cells, deficient in GSH, either inherently, or due to a 16 h incubation with 1 mM buthionine sulphoximine (BSO), rejoined the breaks after MISO treatment at a lower rate and to a lesser extent than did GSH-proficient cells. Without MISO treatment, the hypoxically induced ssb were rejoined in the GSH-deficient cells as effectively as in the proficient cells. It is concluded that a large proportion of the breaks which arise after hypoxic irradiation in the presence of MISO are of a different type to those which arise in the absence of the drug, and require a particular GSH-dependent, enzymatic repair system. This requirement for rejoining in hypoxically irradiated, MISO-treated cells is similar to that seen earlier in MISO-untreated, oxically irradiated cells, and suggests that the ssb induced by radiation in the presence of MISO or oxygen are of a similar nature. (author)

  18. Dose-dependent and gender-related radiation-induced transcription alterations of Gadd45a and Ier5 in human lymphocytes exposed to gamma ray emitted by 60Co

    International Nuclear Information System (INIS)

    Tavakoli, H.; Manoochehri, M.; Mosalla, S. M. M.; Ghafori, M.; Karimi, A. A.

    2013-01-01

    Growth arrest DNA damage-inducible 45a gene (Gadd45a) and immediate early response gene 5 (Ier5) have been emphasised as ideal radiation bio-markers in several reports. However, some aspects of radiation-induced transcriptional alterations of these genes are unknown. In this study, gender-dependency and dose-dependency as two factors that may affect radiation induced transcription of Gadd45a and Ier5 genes were investigated. Human lymphocyte cells from six healthy voluntary blood donors (three women and three men) were irradiated in vitro with doses of 0.5-4.0 Gy from a 60 Co source and RNA isolated 4 h later using the High Pure RNA Isolation Kit. Dose and gender dependency of radiation-induced transcriptional alterations of Gadd45a and Ier5 genes were studied by quantitative real-time polymerase chain reaction. The results showed that as a whole, Gadd45a and Ier5 gave responses to gamma rays, while the responses were independent of radiation doses. Therefore, regardless of radiation dose, Gadd45a and Ier5 can be considered potential radiation bio-markers. Besides, although radiation-induced transcriptional alterations of Gadd45a in female and male lymphocyte samples were insignificant at 0.5 Gy, at other doses, their quantities in female samples were at a significantly higher level than in male samples. Radiation induced transcription of Ier5 of females samples had a reduction in comparison with male samples at 1 and 2 Gy, but at doses of 0.5 and 4 Gy, females were significantly more susceptible to radiation-induced transcriptional alteration of Ier5. (authors)

  19. Effects of a Mangifera indica L. stem bark extract and mangiferin on radiation-induced DNA damage in human lymphocytes and lymphoblastoid cells.

    Science.gov (United States)

    Rodeiro, I; Delgado, R; Garrido, G

    2014-02-01

    Mangifera indica L. (mango) stem bark aqueous extract (MSBE) that has antioxidant, anti-inflammatory and immunomodulatory properties, can be obtained in Cuba. It is rich in polyphenols, where mangiferin is the main component. In this study, we have tested DNA damage and protection effects of MSBE and mangiferin on primary human lymphocytes and lymphoblastoid cells. Cell suspensions were incubated with the products (50-1000 μg/ml) for experiments on damage induction, and evaluation of any potential protective effects (5-100 μg/ml) for 60 min at 37 °C. Irradiation was performed using a γ-ray source, absorbed dose 5 Gy. At the end of exposure, DNA damage, protection and repair processes were evaluated using the comet assay. MSBE (100-1000 μg/ml) induced DNA damage in a concentration dependent manner in both cell types tested, primary cells being more sensitive. Mangiferin (200 μg/ml) only induced light DNA damage at higher concentrations. DNA repair capacity was not affected after MSBE or mangiferin exposure. On the other hand, MSBE (25 and 50 μg/ml) and mangiferin (5-25 ug/ml) protected against gamma radiation-induced DNA damage. These results show MSBE has protector or harmful effects on DNA in vitro depending on the experimental conditions, which suggest that the extract could be acting as an antioxidant or pro-oxidant product. Mangiferin was involved in protective effects of the extract. © 2013 John Wiley & Sons Ltd.

  20. Radiation-induced bystander effects and the DNA paradigm: An 'out of field' perspective

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, C.B.

    2006-01-01

    Over the past 20 years there has been increasing evidence that cells and the progeny of cells surviving a very low dose of ionizing radiation [μ-mGy] can exhibit a wide range of non-monotonic effects such as adaptive responses, low dose hypersensitivity and other delayed effects. These effects are inconsistent with the expected dose-response, when based on extrapolation of high dose data and cast doubt on the reliability of extrapolating from high dose data to predict low dose effects. Recently the cause of many of these effects has been tentatively ascribed to so-called 'bystander effects'. These are effects that occur in cells not directly hit by an ionizing track but which are influenced by signals from irradiated cells and are thus highly relevant in situations where the dose is very low. Not all bystander effects may be deleterious although most endpoints measured involve cell damage or death. In this commentary, we consider how these effects impact the historical central dogma of radiobiology and radiation protection, which is that DNA double strand breaks are the primary radiation-induced lesion which can be quantifiably related to received dose and which determine the probability that a cancer will result from a radiation exposure. We explore the low dose issues and the evidence and conclude that in the very low dose region, the primary determinant of radiation exposure outcome is the genetic and epigenetic background of the individual and not solely the dose. What this does is to dissociate dose from effect as a quantitative relationship, but it does not necessarily mean that the effect is ultimately unrelated to DNA damage. The fundamental thesis we present is that at low doses fundamentally different mechanisms underlie radiation action and that at these doses, effect is not quantitatively related to dose

  1. DNA copy number analysis from mice with radiation-induced acute myeloid leukemia

    Data.gov (United States)

    National Aeronautics and Space Administration — Certain mouse strains such as CBA C3H and RFM have high incidence of radiation-induced acute myeloid leukemia (AML). The data in this series wer generated by using...

  2. Detection and Repair of Ionizing Radiation-Induced DNA Double Strand Breaks: New Developments in Nonhomologous End Joining

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chen [Departments of Biochemistry and Molecular Biology and Oncology, and Southern Alberta Cancer Research Institute, University of Calgary, Calgary (Canada); Lees-Miller, Susan P., E-mail: leesmill@ucalgary.ca [Departments of Biochemistry and Molecular Biology and Oncology, and Southern Alberta Cancer Research Institute, University of Calgary, Calgary (Canada)

    2013-07-01

    DNA damage can occur as a result of endogenous metabolic reactions and replication stress or from exogenous sources such as radiation therapy and chemotherapy. DNA double strand breaks are the most cytotoxic form of DNA damage, and defects in their repair can result in genome instability, a hallmark of cancer. The major pathway for the repair of ionizing radiation-induced DSBs in human cells is nonhomologous end joining. Here we review recent advances on the mechanism of nonhomologous end joining, as well as new findings on its component proteins and regulation.

  3. Gamma radiation induced enhancement in the antioxidant and radioprotective activities of flavonoids

    International Nuclear Information System (INIS)

    Arul Anantha Kumar, A.; Sonwani, Swetha; Bakkiam, D.

    2018-01-01

    Recently γ-radiation has been used as a tool to induce structural changes in natural biomolecules to enhance their biological and physiological properties. Flavonoids are a family of plant derived polyphenolic compounds having considerable scientific and therapeutic importance. Structurally they are the benzo-γ-pyrone derivatives containing phenolic and pyrane rings. Flavonoid radioprotection is an intense area of research thanks to features like natural origin, effectiveness at non-toxic dose levels and lack of side effects. But till date no report is available on the effect of γ-radiation mediated enhancement in radioprotection activity of flavonoids. In view of this the present study was carried out to determine the γ-radiation induced structural changes in selected flavonoids i.e. apigenin, naringenin and genistein and also to explore the possibility of enhancement in their antioxidant and radioprotective activities

  4. Chromatin structure influence the sensitivity of DNA to ionizing radiation induced DNA damage

    International Nuclear Information System (INIS)

    Gupta, Sanjay

    2016-01-01

    Chromatin acts as a natural hindrance in DNA-damage recognition, repair and recovery. Histone and their variants undergo differential post-translational modification(s) and regulate chromatin structure to facilitate DNA damage response (DDR). During the presentation we will discuss the importance of chromatin organization and histone modification(s) during IR-induced DNA damage response in human liver cells. Our data shows G1-phase specific decrease of H3 serine10 phosphorylation in response to DNA damage is coupled with chromatin compaction in repair phase of DDR. The loss of H3Ser10P during DNA damage shows an inverse correlation with gain of γH2AX from a same mono-nucleosome in a dose-dependent manner. The loss of H3Ser10P is a universal phenomenon as it is independent of origin of cell lines and nature of genotoxic agents in G1 phase cells. The reversible reduction of H3Ser10P is mediated by opposing activities of phosphatase, MKP1 and kinase, MSK1 of the MAP kinase pathway. The present study suggests distinct reversible histone marks are associated with G1-phase of cell cycle and plays a critical role in chromatin organization which may facilitate differential sensitivity against radiation. Thus, the study raises the possibility of combinatorial modulation of H3Ser10P and histone acetylation with specific inhibitors to target the radio-resistant cancer cells in G1-phase and thus may serve as promising targets for cancer therapy. (author)

  5. Molecular characterization of a complex site-specific radiation-induced DNA double-strand break

    International Nuclear Information System (INIS)

    Datta, K.; Dizdaroglu, M.; Jaruga, P.; Neumann, R.D.; Winters, T.A.

    2003-01-01

    Radiation lethality is a function of radiation-induced DNA double-strand breaks (DSB). Current models propose the lethality of a DSB to be a function of its structural complexity. We present here for the first time a map of damage associated with a site-specific double-strand break produced by decay of 125 I in a plasmid bound by a 125 I-labeled triplex forming oligonucleotide ( 125 I-TFO). The E. coli DNA repair enzymes, endonuclease IV (endo IV), endonuclease III (endo III), and formamidopyrimidine-DNA glycosylase (Fpg), which recognize AP sites, and pyrimidine and purine base damage respectively, were used as probes in this study. 125 I-TFO bound plasmid was incubated with and without DMSO at -80 deg C for 1 month. No significant difference in DSB yield was observed under these conditions. A 32 base pair fragment from the upstream side of the decay site was isolated by restriction digestion and enzymatically probed to identify damage sites. Endo IV treatment of the 5'-end labeled upper strand indicated clustering of AP sites within 3 bases downstream and 7 bases upstream of the targeted base. Also, repeated experiments consistently detected an AP site 4 bases upstream of the 125 Itarget base. This was further supported by complementary results with the 3'-end labeled upper strand. Endo IV analysis of the lower strand also shows clustering of AP sites near the DSB end. Endo III and Fpg probing demonstrated that base damage is also clustered near the targeted break site. DSBs produced in the absence of DMSO displayed a different pattern of enzyme sensitive damage than those produced in the presence of DMSO. Identification of specific base damage types within the restriction fragment containing the DSB end was achieved with GC/MS. Base damage consisted of 8-hydroguanine, 8-hydroxyadenine, and 5-hydroxycytosine. These lesions were observed at relative yields of 8-hydroguanine and 5-hydroxycytosine to 8-hydroxyadenine of 7.4:1 and 4.7:1, respectively, in the absence

  6. Inhibition of radiation-induced EGFR nuclear import by C225 (Cetuximab) suppresses DNA-PK activity

    International Nuclear Information System (INIS)

    Dittmann, Klaus; Mayer, Claus; Rodemann, Hans-Peter

    2005-01-01

    Background and purpose: Inhibition of EGFR-function can induce radiosensitization in tumor cells. Purpose of our investigation was to identify the possible molecular mechanism of radiosensitization following treatment with anti-EGFR-antibody C225 (Cetuximab). Materials and methods: The effect of C225 on radiation response was determined in human cell lines of bronchial carcinoma (A549) and breast adenoma cells (MDA MB 231). The molecular effects of C225 on EGFR-function after irradiation were analyzed applying western blotting, immune-precipitation and kinase assays. Effects on DNA-repair were detected by quantification of γ-H2AX positive foci 24 h after irradiation. Results: The EGFR specific antibody C225 induced radiosensitization in A549 and also in MDA MB 231 cells. Radiosensitization in A549 was associated with blockage of radiation-induced EGFR transport into the nucleus, and immobilized the complex of EGFR with DNA-dependent protein kinase (DNA-PK) in the cytoplasm. As a consequence radiation-induced DNA-PK activation was abolished, a process that is essential for DNA-repair after radiation exposure. Likewise C225 treatment increased the residual amount of γ-H2AX-positive foci 24 h after irradiation in A549 and in MDA MB 231 cells. Conclusions: Our results suggest that irradiation induced DNA-PK activation-essential for DNA repair-may be hampered specifically by use of the anti-EGFR-antibody C225. This process is associated with radiosensitization

  7. Radiation-induced DNA damage and repair in radiosensitive and radioresistant human tumour cells measured by field inversion gel electrophoresis

    International Nuclear Information System (INIS)

    Smeets, M.F.M.A.; Mooren, E.H.M.; Begg, A.C.

    1993-01-01

    Radiation-induced DNA damage induction and repair was measured in two human squamous carcinoma cell lines with differing radiosensitivities. Experiments were carried out with field inversion gel electrophoresis (FIGE), adapted to measure DNA double strand break (DSB) induction and repair in unlabelled cells. The sensitivity of the method was increased by introducing a hybridization membrane into the agarose gel. Damaged DNA accumulated on one spot on the membrane resulting in high local concentrations. This DNA was quantified using radioactively-labelled total human DNA as a probe. Radiosensitivity differences at physiological temperatures could not be explained by differences in either induction or repair of DNA damage as measured by pulsed field gel electrophoresis. (author)

  8. Gamma radiation-induced Impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens

    International Nuclear Information System (INIS)

    Khoshbin khoshnazar, A. R; Jahanshahi, M; Azami, N. S

    2012-01-01

    Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells

  9. Dose-Related Effects of Acetylsalicylic acid (ASA) on Gamma Radiation-Induced Teratogenicity in Pregnant Albino Rats

    International Nuclear Information System (INIS)

    Ibrahim, M.F.

    2013-01-01

    Reviews of acetylsalicylic acid (ASA), a widely used nonsteroidal anti- inflammatory drug, has consistently suggested a possible association between prenatal ASA ingestion and adverse effects in the pregnant mothers and their developing fetuses. The objective of the current study was to comprehensively define the effect of relatively low and high doses of ASA (25 mg/kg body wt. and 200 mg/kg body wt. respectively) on gestating rats and their possible impact on the irradiated ones. Therefore 36 pregnant rats were randomly divided into 6 equal groups. Three rat groups were daily orally gavaged from the 7th to the 18th gestational days with: distilled water (Group 1), 25 mg/kg body wt. ASA (Group 2) and 200 mg/kg body wt. ASA (Group 3). The other three groups similarly received the same previous treatments besides 2 Gy whole body gamma irradiation of each, to serve as: Group 4 (distilled water + irradiation), Group 5 (25 mg/kg body wt. ASA + irradiation) and Group 6 (200 mg/kg body wt. ASA + irradiation). All rat groups were sacrificed on the 20th day of pregnancy and the uterine contents were examined. The lower ASA dose (25 mg/kg body wt.) treated group (Group 2) displayed healthy mothers and fetuses whereas that of the higher dose (200 mg/kg body wt.) (Group 3) despite not showing significant maternal or fetal mortalities, yet the intrauterine contents presented fetal developmental disorders including stunted growth and resorption together with some head and limb anomalies including plagiocephaly, marked acampsia and acrocontracture. Meanwhile, results have unexpectedly shown a radioprotective role of the lower ASA dose (25 mg/kg. body wt.) (Group 5) to pregnant rats and their fetuses as inspected by its efficacy in retrieving the radiation induced maternal weight loss together with its noticeable ameliorating effects on the intrauterine lethality of the affected fetuses and their externally detected abnormalities in addition toits effectiveness in retaining some

  10. Moderate acute intake of de-alcoholised red wine, but not alcohol, is protective against radiation-induced DNA damage ex vivo-Results of a comparative in vivo intervention study in younger men

    Energy Technology Data Exchange (ETDEWEB)

    Greenrod, W. [CSIRO Health Sciences and Nutrition, Genome Health and Nutrigenomics Laboratory, PO Box 10041, Adelaide BC, SA 5000 (Australia); Department of Clinical and Experimental Pharmacology, University of Adelaide, South Australia (Australia); Stockley, C.S. [Australian Wine Research Institute, South Australia (Australia); Burcham, P. [Department of Clinical and Experimental Pharmacology, University of Adelaide, South Australia (Australia); Abbey, M. [CSIRO Health Sciences and Nutrition, Genome Health and Nutrigenomics Laboratory, PO Box 10041, Adelaide BC, SA 5000 (Australia); Fenech, M. [CSIRO Health Sciences and Nutrition, Genome Health and Nutrigenomics Laboratory, PO Box 10041, Adelaide BC, SA 5000 (Australia)]. E-mail: michael.fenech@hsn.csiro.au

    2005-12-11

    Moderate intake of wine is associated with reduced risk of cardiovascular disease and possibly cancer however it remains unclear whether the potential health benefits of wine intake are due to alcohol or the non-alcoholic fraction of wine. We therefore tested the hypothesis that the non-alcoholic fraction of wine protects against genome damage induced by oxidative stress in a crossover intervention study involving six young adult males aged 21-26 years. The participants adhered to a low plant phenolic compound diet for 48 h prior to consuming 300 mL of complete red wine, dealcoholised red wine or ethanol on separate occasions 1 week apart. Blood samples were collected 0.5, 1.0 and 2.0 h after beverage consumption. Baseline and radiation-induced genome damage was measured using the cytokinesis-block micronucleus assay and total plasma catechin concentration was measured. Consumption of dealcoholised red wine significantly decreased the gamma radiation-induced DNA damage at 1 and 2 h post-consumption by 20%. In contrast alcohol tended to increase radiation-induced genome damage and complete wine protected against radiation-induced genome damage relative to alcohol. The observed effects were only weakly correlated with the concentration of total plasma catechin (R = -0.23). These preliminary data suggest that only the non-alcoholic fraction of red wine protects DNA from oxidative damage but this effect cannot be explained solely by plasma catechin.

  11. Moderate acute intake of de-alcoholised red wine, but not alcohol, is protective against radiation-induced DNA damage ex vivo-Results of a comparative in vivo intervention study in younger men

    International Nuclear Information System (INIS)

    Greenrod, W.; Stockley, C.S.; Burcham, P.; Abbey, M.; Fenech, M.

    2005-01-01

    Moderate intake of wine is associated with reduced risk of cardiovascular disease and possibly cancer however it remains unclear whether the potential health benefits of wine intake are due to alcohol or the non-alcoholic fraction of wine. We therefore tested the hypothesis that the non-alcoholic fraction of wine protects against genome damage induced by oxidative stress in a crossover intervention study involving six young adult males aged 21-26 years. The participants adhered to a low plant phenolic compound diet for 48 h prior to consuming 300 mL of complete red wine, dealcoholised red wine or ethanol on separate occasions 1 week apart. Blood samples were collected 0.5, 1.0 and 2.0 h after beverage consumption. Baseline and radiation-induced genome damage was measured using the cytokinesis-block micronucleus assay and total plasma catechin concentration was measured. Consumption of dealcoholised red wine significantly decreased the gamma radiation-induced DNA damage at 1 and 2 h post-consumption by 20%. In contrast alcohol tended to increase radiation-induced genome damage and complete wine protected against radiation-induced genome damage relative to alcohol. The observed effects were only weakly correlated with the concentration of total plasma catechin (R = -0.23). These preliminary data suggest that only the non-alcoholic fraction of red wine protects DNA from oxidative damage but this effect cannot be explained solely by plasma catechin

  12. Radiation induced asymmetries in mitotic recombination: evidence for a directional bias in the formation of asymmetric hybrid DNA in yeast

    International Nuclear Information System (INIS)

    Friedman, L.R.; Sobell, H.M.

    We have examined radiation-induced mitotic recombination using two alleles (his1-36, his1-49) in the his1 gene. When the haploid containing his1-36 is irradiated with varying doses of γ rays and then mated with the unirradiated strain containing his1-49, analyses of the selected prototrophs show them to be primarily + +/+ 49. If, on the other hand, the haploid strain containing his1-49 is the irradiated parent, the prototrophic diploids are primarily + +/36 +. In control experiments, where either both strains are irradiated or not irradiated, no such asymmetries are found. These data indicate that the irradiated haploid chromosome tends to be the recipient of genetic information. We interpret these results as indicating a directional bias in the formation of hybrid DNA in radiation-induced mitotic recombination, and discuss these results in terms of current models of genetic recombination

  13. Elucidaton of DNA methylation changes in response to ionizng radiation induced double strand breaks

    Energy Technology Data Exchange (ETDEWEB)

    Herrlitz, Maren Linda

    2014-07-04

    would be an effect of overexpression or be indicative of a possible function in these nuclear subcompartments is yet to be elucidated. Additionally, by using flow cytometry analysis, exposure to IR and concomitant overexpression of TET2CD-GFP strongly induced 5hmC formation, therefore suggesting a function of TET2 in response to irradiation. Recruitment analysis showed that the TET2 catalytic domain was recruited to UV laser-induced but not X-rays- or heavy ion-induced damage sites. Endogenous TET2, which was analyzed in high TET2 expressing human fibroblasts, was recruited to damage sites after irradiation with heavy ions or X-rays. As 5hmC is the direct product of the catalytic activity of TET enzymes, local 5hmC formation and abundance at damage sites was investigated. It was observed that 5hmC accumulated at heavy ion- as well as X-ray-induced DNA double strand breaks (DSBs). In addition, investigating 5hmC foci over time after irradiation with X-rays revealed that 5hmC formation and kinetics is similar to that of γH2AX foci, whereby every 5hmC focus co-localized with γH2AX. However, this did not hold true for all γH2AX foci, whose total number was always higher than that of 5hmC. Furthermore, 5hmC (and γH2AX) foci formation was almost unaffected by the inhibition of DNA-PKcs' enzymatic activity. Conversely, 5hmC and γH2AX foci persistence was significantly delayed after DNA-PKcs inhibition. Results obtained in this thesis show that DNA methylation changes (5hmC formation) take place within the time frame of one replication cycle after exposure to IR and that these changes can be observed at sites of DSBs. 5hmC at DSBs might be formed by the oxidative function of TET2, which was shown to be recruited to DSBs. However, involvement of the other TET enzymes in 5hmC production cannot be excluded. Therefore, these results suggest a role of 5hmC in the response to IR induced DSBs, whereby the here presented data suggest that the fast, radiation induced

  14. Radiation-induced decomposition of the purine bases within DNA and related model compounds

    International Nuclear Information System (INIS)

    Cadet, J.; Berger, M.

    1985-01-01

    This survey focuses on recent developments in the radiation chemistry of purine bases in nucleic acids and related model compounds. Both direct and indirect effects of ionizing radiation are investigated with special emphasis on the structural characterization of the final decomposition products of nucleic acid components. Available assays for monitoring radiation-induced base lesions are critically reviewed. (author)

  15. Individual repair of radiation-induced DNA double-strand breaks in lymphocytes. Implications for radiation-induced dermatitis in breast cancer

    International Nuclear Information System (INIS)

    Melchior, Patrick Wilhelm

    2011-01-01

    Purpose: Adjuvant 'whole breast radiotherapy' (WBRT) is the standard of care after breast conserving surgery in women with breast cancer. Throughout different cancer stages the addition of WBRT leads to significantly improved rates of freedom from local failure and overall survival. WBRT is generally well tolerated. A 5-10%-rate of severe acute or long-term side effects is commonly observed. For both radiation-mediated tumor-cell-elimination and induction of side effects, DNA-double-strand-breaks (DSB) presumably play the decisive role. The intensity of normal tissue reactions in radiotherapy can, in part, be attributed to the intrinsic DSB repair-capacity. In this study in vivo and in vitro experiments are carried through in order to assess DSB repair-kinetics in blood lymphocytes of women with breast cancer. These findings are to be correlated with the degree of radiation-induced normal tissue toxicity. Patients and Methods: Eighteen patients with breast cancer, in whom WBRT was indicated, were examined. A total WBRT dose of 50 Gy (single dose 2 Gy) with an additional boost-radiotherapy to the initial tumor-region to a total dose of 60-66 Gy was administered. DSB repair was determined by means of counting γ-H2AX foci in blood lymphocytes at predefined points in time, i.e. before and 0.5 h; 2.5 h; 5 h and 24 h after in vivo irradiation (1st fraction of WBRT) and before and 0.5 h; 2.5 h and 5 h after in vitro irradiation with increasing radiation doses in the range of 10 - 500 mGy. Acute normal tissue toxicity was scored on the basis of a modified RTOG-classification (main aspects were erythema and dry or moist skin desquamation). Results: DSB repair-halflife-times did not differ between patients with a higher or lower than average incidence of acute side effects. In patients with 'above average' side effects larger irradiation volumes were treated (volume surrounded by the 50%-isodose). Adjusted for these, no single patients showed elevated residual γ-H2AX foci

  16. cDNA cloning and transcriptional controlling of a novel low dose radiation-induced gene and its function analysis

    International Nuclear Information System (INIS)

    Zhou Pingkun; Sui Jianli

    2002-01-01

    Objective: To clone a novel low dose radiation-induced gene (LRIGx) and study its function as well as its transcriptional changes after irradiation. Methods: Its cDNA was obtained by DDRT-PCR and RACE techniques. Northern blot hybridization was used to investigate the gene transcription. Bioinformatics was employed to analysis structure and function of this gene. Results: LRIGx cDNA was cloned. The sequence of LRIGx was identical to a DNA clone located in human chromosome 20 q 11.2-12 Bioinformatics analysis predicted an encoded protein with a conserved helicase domain. Northern analysis revealed a ∼8.5 kb transcript which was induced after 0.2 Gy as well as 0.02 Gy irradiation, and the transcript level was increased 5 times at 4 h after 0.2 Gy irradiation. The induced level of LRIGx transcript by 2.0 Gy high dose was lower than by 0.2 Gy. Conclusion: A novel low dose radiation-induced gene has been cloned. It encodes a protein with a conserved helicase domain that could involve in DNA metabolism in the cellular process of radiation response

  17. Screening of gamma radiation-induced pathogen resistance rice lines against Xanthomonas oryzae pv. oryzae

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Chan Ju; Lee, Ha Yeon; Kim, Woong Bom; Ahmad, Raza; Moon, Jae Sun; Kwon, Suk Yoon [Korea Research Institute of Beoscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Dong Sub [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-09-15

    Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of M{sub 3}, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In M{sub 4} generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

  18. Radiation-induced reduction of diuron by gamma-ray irradiation

    International Nuclear Information System (INIS)

    Zhang Jibiao; Zheng Zheng; Zhao Tan; Zhao Yongfu; Wang Lianhong; Zhong Yun; Xu Yue

    2008-01-01

    Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L -1 and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl - ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with ·OH and e aq - . The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H 2 O 2 , HCO 3 - , NO 3 - , NO 2 - , CH 3 OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO 3 - , NO 2 - , CH 3 OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation

  19. Radiation-induced reduction of diuron by gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jibiao [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zheng Zheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)], E-mail: zzheng@nju.edu.cn; Zhao Tan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhao Yongfu [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Institute of Atomic Energy, Jiangsu Academy of Agriculture Sciences, Nanjing 210014 (China); Wang Lianhong; Zhong Yun; Xu Yue [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2008-03-01

    Diuron degradation efficiencies and the proposed mechanism by gamma-ray irradiation were investigated. Several factors that might affect the degradation values were further examined. The UV absorbances at 200-400 nm and diuron concentration decreased with the increase of radiation dose. When diuron initial concentration was 18.5 mg L{sup -1} and 1.0 kGy was selected as the radiation dose, diuron removal value and loss of total organic carbon were 100 and 34.1%, respectively. However, the concentration of Cl{sup -} ion increased with the increase of radiation dose. The process could be depicted by first order reaction kinetics and the reaction was mainly caused by the reaction of diuron with {center_dot}OH and e{sub aq}{sup -}. The degradation efficiency decreased with the increase of initial concentration at the same radiation dose. H{sub 2}O{sub 2}, HCO{sub 3}{sup -}, NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid as additives reduced the degradation efficiency. Furthermore, the increase of NO{sub 3}{sup -}, NO{sub 2}{sup -}, CH{sub 3}OH and humic acid would result in the decrease of the degradation values. The pH value could affect the removal efficiency and the degradation process was enhanced in acid condition. The pH value became lower with increasing radiation dose after gamma-ray irradiation.

  20. Application of capillary gas chromatography-mass spectrometry to chemical characterization of radiation-induced base damage of DNA: implications for assessing DNA repair processes

    International Nuclear Information System (INIS)

    Dizdaroglu, M.

    1985-01-01

    The application of capillary gas chromatography-mass spectrometry (GC-MS) to the chemical characterization of radiation-induced base products of calf thymus DNA is presented. Samples of calf thymus DNA irradiated in N 2 O-saturated aqueous solution were hydrolyzed with HCOOH, trimethylsilylated, and subjected to GC-MS analysis using a fused-silica capillary column. Hydrolysis conditions suitable for the simultaneous analysis of the radiation-induced products of all four DNA bases in a single run were determined. The trimethylsilyl derivatives of these products had excellent GC properties and easily interpretable mass spectra; an intense molecular ion (M+.) and a characteristic (M-CH 3 )+ ion were observed. The complementary use of t-butyldimethylsilyl derivatives was also demonstrated. These derivatives provided an intense characteristic (M-57)+ ion, which appeared as either the base peak or the second most intense ion in the spectra. All mass spectra obtained are discussed

  1. Gamma radiation-induced preparation of some acrylamide polymers for treatment of waste water

    International Nuclear Information System (INIS)

    Siyam, T.; Hanna, E.

    1992-01-01

    Water-soluble acrylamide copolymers such as: poly (acrylamide-co-sodium) [P(AM-CO-AA Na)], (acrylamide-CO-diallylethylamine-hydrochloride) [P(AM-CO-DAEA-H Cl)] and poly (acrylamide-sodium acrylate-diallylethylamine-hydrochloride) [P(AM-AANa-DAEA-H Cl)] were prepared by gamma radiation-initiated polymerization of the corresponding co monomer or termonomer solutions. The prepared copolymers were used in the treatment of water (metal sulphate solutions). It was found that the polymer efficiency increases with increasing the PH-value and the polymer concentration. The efficiency of the different polymers compared in what concerns elimination of Cu++ and Mg++. The polymer dosage depends on the hydration sheath of the cation. The mechanism for interaction of each polymeric chains with the ions of waste water was also discussed. 3 figs, 1 tab

  2. Genetic signatures from amplification profiles characterize DNA mutation in somatic and radiation-induced sports of chrysanthemum

    International Nuclear Information System (INIS)

    Trigiano, R.N.; Scott, M.C.; Caetano-Anolles, G.

    1998-01-01

    The chrysanthemum (Dendranthema grandiflora Tzvelev.) cultivars 'Dark Charm', 'Salmon Charm', 'Coral Charm' and 'Dark Bronze Charm' are either radiation-induced mutants or spontaneous sports of 'Charm' and constitute a family or series of plants that primarily differ in flower color. These cultivars, which were difficult to differentiate genetically by DNA amplification fingerprinting (DAF), were easily identified by using arbitrary signatures from amplification profiles (ASAP). Genomic DNA was first amplified with three standard octamer arbitrary primers, all of which produced monomorphic profiles. Products from each of these DNA fingerprints were subsequently reamplified using four minihairpin decamer primers. The 12 primer combinations produced signatures containing approximately 37% polymorphic character loci, which were used to estimate genetic relationships between cultivars. Forty-six (32%) unique amplification products were associated with individual cultivars. The number of ASAP polymorphisms detected provided an estimate of the mutation rate in the mutant cultivars, ranging from 0.03% to 1.6% of nucleotide changes within an average of 18 kb of arbitrary amplified DAF sequence. The ASAP technique permits the clear genetic identification of somatic mutants and radiation-induced sports that are genetically highly homogeneous and should facilitate marker assisted breeding and protection of plant breeders rights of varieties or cultivars

  3. Cloning of low dose radiation induced gene RIG1 by RACE based on non-cloned cDNA library

    International Nuclear Information System (INIS)

    Luo Ying; Sui Jianli; Tie Yi; Zhang Yuanping; Zhou Pingkun; Sun Zhixian

    2001-01-01

    Objective: To obtain full-length cDNA of radiation induced new gene RIG1 based on its EST fragment. Methods: Based on non-cloned cDNA library, enhanced nested RACE PCR and biotin-avidin labelled probe for magnetic bead purification was used to obtain full-length cDNA of RIG1. Results: About 1 kb of 3' end of RIG1 gene was successfully cloned by this set of methods and cloning of RIG1 5' end is proceeding well. Conclusion: The result is consistent with the design of experiment. This set of protocol is useful for cloning of full-length gene based on EST fragment

  4. Gamma and electron beam radiation induced physico-chemical modifications of poly(propylene)

    Science.gov (United States)

    Yagoubi, N.; Peron, R.; Legendre, B.; Grossiord, J. L.; Ferrier, D.

    1999-05-01

    The homopolymer PP, a plastic material used as packaging and for medical products, must be subjected to a form of sterilization. Nowadays, one kind of this technology uses ionising radiation, which can be γ-rays or electron beams. In order to study the structural modifications of polymer syringes which could occur following these treatments at different doses (25-150 kGy), several analytical techniques have been used. DSC provided information on changes in the cristallinity of the polymer. The thermal evaluation was supplemented by testing the rheological properties of polypropylene. In addition, Reversed Phase Liquid Chromatography (HPLC) with a quaternary elution gradient was carried out for the evaluation of the degradation of the additives. Thermogravimetric analysis (TGA) coupled with Fourier transform infrared (TGA/FTIR) was used to measure the desorption of food simulating liquid (CH 2Cl 2). First, the results obtained proved that the γ-rays as well as the electron beam induced degradation of the polymer and its additives. Next, we compared the effects of gamma and electron beam irradiation to determine which of these two processes better maintained the integrity of the irradiated product.

  5. Development of gamma radiation induced mutants of Nipponbare and their characteristics

    International Nuclear Information System (INIS)

    Antipuesto, M.W.; Braceros, R.C.; Pastor, H.M.; Padolina, T.F.

    2005-01-01

    Nipponbare, a japonica rice subspecies, was the variety sequenced by the Syngenta Team and the International Rice Genome Sequencing Project (IRGSP). It was also selected for the production of mutated population for its use in these projects and for possible application of generated mutants in functional genomics. The basic seed stock of Nipponbare was also taken from the same source of the IRGSP through the National Rice Germplasm Evaluation and Enhancement Center in Stutgart, Arkansas. The authors have produced a total of 1,063 M3 gamma radiated mutants in their collection. However, only 342 desirable mutants were pursued for phenotyping. As a result, 47 agronomically important line were isolated for further characterization for any altered response to biotic, and physiological traits. Initial result from the SSR genotyping using SSR markers (RM 312, RM 323, RM 208, RM 138, RM 156, RM 261, RM 164, and RM 122), the mutants that were assayed exhibited the same allelic pattern as the wild type and therefore, it showed the same nuclear genetic background of the wild type

  6. Acetylation dynamics of human nuclear proteins during the ionizing radiation-induced DNA damage response

    DEFF Research Database (Denmark)

    Bennetzen, Martin; Andersen, J.S.; Lasen, D.H.

    2013-01-01

    Genotoxic insults, such as ionizing radiation (IR), cause DNA damage that evokes a multifaceted cellular DNA damage response (DDR). DNA damage signaling events that control protein activity, subcellular localization, DNA binding, protein-protein interactions, etc. rely heavily on time...

  7. Gamma-radiation induced damage of proteins in the thick fraction of egg white

    Directory of Open Access Journals (Sweden)

    MARIJA VUCKOVIC

    2005-11-01

    Full Text Available The thick fraction of egg white saturated with either N2O or Ar was irradiated in the dose range 1.5–45 kGy at 60Co gamma source. The gel structure decomposition and other processes accompanied with changes in protein molecular mass were followed by Sephadex G-200 exclusion chromatography, denaturing SDS-polyacrylamide gel electrophoresis, viscosity and turbidity measurements. The complex behaviour of viscosity was observed in the N2O saturated sample (where the hydrated electron was converted into the OH radical; the initial abrupt decrease that radually slows down reaching the minimum at 12 kGy (hmin = 2.7 mPa s followed by the slow rise was measured. The Ar saturated sample ([eaq-] ~ [OH] showed both the significantly faster initial decrease and lower viscosity minimum (hmin = 2.2 mPa s. The combined Sephadex G-200 exclusion chromatography and denaturing SDS-polyacrylamide gel electrophoresis data revealed that the three-dimensional egg white (hydrated gel structure was (efficiently decomposed even in the N2O saturated sample. The protein scission was detected in the entire dose range studied, while the protein agglomeration is not noticed at low doses (around 1.5 kGy; however, it dominates at higher doses. In the highest dose region studied, the loss of structure in SDS-PAGE chromatograms indicates that the agglomerates are formed from protein fragments rather than from intact proteins. The continuous linear increase in turbidity was measured. The results obtained indicate that ionizing radiation causes the breakdown of the protein network of the thick fraction of egg white via the reduction of S–S bridges by the hydrated electron and the protein fragmentation due to the direct action of ionizing radiation. The protein agglomeration is initiated by the reaction of the OH radical; its inefficiency at low doses is attributed to the glucose antioxidant properties and radical immobility.

  8. Increase of RhoB in {gamma}-radiation-induced apoptosis is regulated by c-Jun N-terminal kinase in Jurkat T cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chun-Ho [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of); Won, Misun; Choi, Chung-Hae; Ahn, Jiwon; Kim, Bo-Kyung [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of); Song, Kyung-Bin [Department of Food Science and Technology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Kang, Chang-Mo, E-mail: kangcm@kcch.re.kr [Laboratory of Cytogenetics and Tissue Regeneration, KIRAMS, Seoul 139-706 (Korea, Republic of); Chung, Kyung-Sook, E-mail: kschung@kribb.re.kr [Genome Research Center, KRIBB, Daejeon 305-806 (Korea, Republic of)

    2010-01-08

    The Ras-related small GTP-binding protein RhoB is known to be a pro-apoptotic protein and immediate-early inducible by genotoxic stresses. In addition, JNK activation is known to function in {gamma}-radiation-induced apoptosis. However, it is unclear how JNK activation and {gamma}-radiation-dependent RhoB induction are related. Here we verified the relationship between JNK activation and RhoB induction. RhoB induction by {gamma}-radiation occurred at the transcriptional level and transcriptional activation of RhoB was concomitant with an increase in RhoB protein. {gamma}-Radiation-induced RhoB expression was markedly attenuated by pretreatment with a JNK-specific inhibitor, SP600125, but not by a p38 MAPK inhibitor, SB203580. Inhibition of JNK caused a decrease in early apoptotic cell death that correlated with RhoB expression. However, PI3K inhibition had no significant effects, indicating that the AKT survival pathway was not involved. The siRNA knockdown of JNK resulted in a decrease in RhoB expression and the siRNA knockdown of RhoB restored cell growth even in the {gamma}-irradiated cells. These results suggest that RhoB regulation involves the JNK pathway and contributes to the early apoptotic response of Jurkat T cells to {gamma}-radiation.

  9. Radiation-induced upregulation of gene expression from adenoviral vectors mediated by DNA damage repair and regulation.

    Science.gov (United States)

    Nokisalmi, Petri; Rajecki, Maria; Pesonen, Sari; Escutenaire, Sophie; Soliymani, Rabah; Tenhunen, Mikko; Ahtiainen, Laura; Hemminki, Akseli

    2012-05-01

    In the present study, we evaluated the combination of replication-deficient adenoviruses and radiotherapy in vitro. The purpose of the present study was to analyze the mechanism of radiation-mediated upregulation of adenoviral transgene expression. Adenoviral transgene expression (luciferase or green fluorescent protein) was studied with and without radiation in three cell lines: breast cancer M4A4-LM3, prostate cancer PC-3MM2, and lung cancer LNM35/enhanced green fluorescent protein. The effect of the radiation dose, modification of the viral capsid, and five different transgene promoters were studied. The cellular responses were studied using mass spectrometry and immunofluorescence analysis. Double strand break repair was modulated by inhibitors of heat shock protein 90, topoisomerase-I, and DNA protein kinase, and transgene expression was measured. We found that a wide range of radiation doses increased adenoviral transgene expression regardless of the cell line, transgene, promoter, or viral capsid modification. Treatment with adenovirus, radiation, and double strand break repair inhibitors resulted in persistence of double strand breaks and subsequent increases in adenovirus transgene expression. Radiation-induced enhancement of adenoviral transgene expression is linked to DNA damage recognition and repair. Radiation induces a global cellular response that results in increased production of RNA and proteins, including adenoviral transgene products. This study provides a mechanistic rationale for combining radiation with adenoviral gene delivery. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. FTS is responsible for radiation-induced nuclear phosphorylation of EGFR and repair of DNA damage in cervical cancer cells.

    Science.gov (United States)

    Muthusami, Sridhar; Prabakaran, D S; Yu, Jae-Ran; Park, Woo-Yoon

    2015-02-01

    Radiation-induced nuclear stabilization and phosphorylation of epidermal growth factor receptor (EGFR) confers radioresistance. Understanding of the factor(s) regulating the nuclear stabilization and phosphorylation of EGFR is important for the modulation of radioresistance. Present study was designed to delineate the regulation of EGFR nuclear stabilization and phosphorylation by fused toes homolog (FTS), an oncoprotein, which is responsible for the radioresistance in cervical cancer cells. A cervical cancer cell line, ME180 was used. Radiation-induced change in the levels of EGFR, p-EGFR and FTS were evaluated in the cytoplasm and nucleus using Western blot analyses. FTS was silenced using siRNA-based approach. Interaction between EGFR and FTS was assessed using immunofluorescence and immunoprecipitation analyses. Double-strand breaks (DSB) of DNA were assessed using γ H2AX. Radiation increased the levels of EGFR and FTS in the cytoplasm and nucleus. EGFR and FTS are in physical association with each other and are co-localized in the cells. FTS silencing largely reduced the nuclear stabilization and phosphorylation of EGFR and DNA-protein kinase along with increased initial and residual DSBs. EGFR and FTS physically associate with each other and FTS silencing radiosensitizes ME180 cells through impaired nuclear EGFR signaling.

  11. Radiation-Induced Upregulation of Gene Expression From Adenoviral Vectors Mediated by DNA Damage Repair and Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Nokisalmi, Petri; Rajecki, Maria; Pesonen, Sari; Escutenaire, Sophie [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland); Soliymani, Rabah [Protein Chemistry Unit, Department of Anatomy, Institute of Biomedicine, Biomedicum Helsinki (Finland); Tenhunen, Mikko [Department of Radiation and Oncology, Helsinki University Central Hospital, Helsinki (Finland); Ahtiainen, Laura [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland); Hemminki, Akseli, E-mail: akseli.hemminki@helsinki.fi [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland)

    2012-05-01

    Purpose: In the present study, we evaluated the combination of replication-deficient adenoviruses and radiotherapy in vitro. The purpose of the present study was to analyze the mechanism of radiation-mediated upregulation of adenoviral transgene expression. Methods and Materials: Adenoviral transgene expression (luciferase or green fluorescent protein) was studied with and without radiation in three cell lines: breast cancer M4A4-LM3, prostate cancer PC-3MM2, and lung cancer LNM35/enhanced green fluorescent protein. The effect of the radiation dose, modification of the viral capsid, and five different transgene promoters were studied. The cellular responses were studied using mass spectrometry and immunofluorescence analysis. Double strand break repair was modulated by inhibitors of heat shock protein 90, topoisomerase-I, and DNA protein kinase, and transgene expression was measured. Results: We found that a wide range of radiation doses increased adenoviral transgene expression regardless of the cell line, transgene, promoter, or viral capsid modification. Treatment with adenovirus, radiation, and double strand break repair inhibitors resulted in persistence of double strand breaks and subsequent increases in adenovirus transgene expression. Conclusions: Radiation-induced enhancement of adenoviral transgene expression is linked to DNA damage recognition and repair. Radiation induces a global cellular response that results in increased production of RNA and proteins, including adenoviral transgene products. This study provides a mechanistic rationale for combining radiation with adenoviral gene delivery.

  12. The prevention of radiation-induced DNA damage and apoptosis in human intestinal epithelial cells by salvianic acid A

    Directory of Open Access Journals (Sweden)

    Yanjun Zhang

    2014-07-01

    Full Text Available The topic of radiation always provokes public debate, and the uses of radiation for therapeutic and other purposes have always been associated with some anxiety. Salvia miltiorrhiza Bunge has been widely used for the treatment of various diseases including cerebrovascular diseases, coronary artery diseases, and myocardial infarction. Salvianolic acid A (SAA d (+-(3,4-dihydroxyphenyl lactic acid is the principal effective, watersoluble constituent of Salvia miltiorrhiza Bunge. In our present study, radiation-induced DNA damage and apoptosis in human intestinal epithelial cells (HIEC in the presence and absence of SAA were examined. We investigated the effects of SAA on ROS formation and the activity of enzymatic antioxidants (SOD, the lipid peroxidative index and the levels of non-enzymatic antioxidant (GSH. Finally, we investigated whether the reduction of radiation-induced cell death caused by SAA might be related to mitochondria-dependent apoptosis. Present findings indicate that SAA is a promising radioprotective agent with a strong antioxidant activity. SAA exerted its protective action on the proliferative activity of HIEC cells as evidenced by decreased cytotoxicity after exposure to γ-radiation. It is possible that SAA achieved its radioprotective action, at least in part, by enhancing DNA repair and the activity of antioxidant enzymes, by scavenging ROS and by inhibiting the mitochondria-dependent apoptotic pathway.

  13. Attenuation of radiation-induced DNA damage due to paracrine interactions between normal human epithelial and stromal cells

    International Nuclear Information System (INIS)

    Saenko, V.A.; Nakazawa, Yu.; Rogounovitch, T.I.; Suzuki, K.; Mitsutake, N.; Matsuse, M.; Yamashita, S.

    2007-01-01

    Complete text of publication follows. Objective: Developmentally, every tissue accommodates different types of cells, such as epitheliocytes and stromal cells in parenchymal organs. To better understand the complexity of radiation response, it is necessary to evaluate possible cross-talk between different tissue components. This work was set out to investigate reciprocal influence of normal human epithelial cells and fibroblasts on the extent of radiation-induced DNA damage. Methods: Model cultures of primary human thyrocytes (PT), normal diploid fibroblasts (BJ), PT/BJ cell co-culture and conditioned medium transfer were used to examine DNA damage in terms of γ-H2AX foci number per cell or by Comet assay after exposure to different doses of γ-rays. Results: In co-cultures, the kinetics of γ-H2AX foci number change was dose-dependent and similar to that in individual PT and BJ cultures. The number of γ-H2AX foci in co-cultures was significantly lower (∼25%) in both types of cells comparing to individual cultures. Reciprocal conditioned medium transfer to individual counterpart cells prior to irradiation resulted in approximately 35% reduction in the number γ-H2AX foci at 1 Gy and lower doses in both PT and BJ demonstrating the role of paracrine soluble factors. Comet assay corroborated the results of γ-H2AX foci counting in conditioned medium transfer experiments. In contrast to medium conditioned on PT cells, conditioned medium collected from several human thyroid cancer cell lines failed to establish DNA-protected state in BJ fibroblasts. In its turn, medium conditioned on BJ cells did not change the extent of radiation-induced DNA damage in cancer cell lines tested. Conclusion: The results imply the existence of a network of soluble factor-mediated paracrine interactions between normal epithelial and stromal cells that could be a part of natural mechanism by which cells protect DNA from genotoxic stress.

  14. The influence of chromatin structure on the frequency of radiation-induced DNA strand breaks: a study using nuclear and nucleoid monolayers

    International Nuclear Information System (INIS)

    Ljungman, M.

    1991-01-01

    To assess the influence of chromatin structure on the frequency of radiation-induced DNA strand breaks, the alkaline unwinding technique was applied to nuclear and nucleoid monolayers. These chromatin substrates were prepared by treating human fibroblasts grown as monolayers with the nonionic detergent Triton X-100 and varying concentrations of cations. The chromatin structure was modified either by a stepwise removal of DNA-bound proteins by extraction in increasing concentrations of monovalent salt, or by the addition or deletion of mono- and divalent cations to condense or decondense the chromatin, respectively. It was found that the stepwise removal of DNA-bound proteins from the chromatin dramatically increased the frequency of radiation-induced DNA strand breaks. The DNA-bound proteins showed a qualitative difference in their ability to protect the DNA where proteins removed by salt concentrations above 1.0 M exerted the greatest protection. Furthermore, the frequency of radiation-induced DNA strand breaks was found to be 6 times lower in condensed chromatin than in decondensed chromatin and about 80 times lower than in protein-depleted chromatin. It is concluded that the presence of DNA-bound proteins and the folding of the chromatin into higher-order structures protect the DNA against radiation-induced strand breaks

  15. Radioprotective effect of methanolic root extract of Loeseneriella arnottiana on radiation induced DNA damage in human lymphocytes in vitro

    International Nuclear Information System (INIS)

    Prajna, P.S.

    2012-01-01

    Intense exposure to ionization radiation by accidental, occupational or therapeutical purpose causes cellular damage mainly by formation of excessive reactive oxygen species (ROS) or by free radicals. Humans are intentionally exposed to ionising radiation for diagnostic or therapeutic purposes. The use of ionising radiation in cancer therapy may lead to transient and/or permanent injury to normal tissues within the treatment field. To increase the therapeutic index of radiation therapy, various modes of radioprotection have been developed that selectively reduce cytotoxic effects to normal tissues. Because radiation-induced cellular damage is attributed primarily to the harmful effects of free radicals, molecules with radical scavenging properties are particularly promising as radioprotectors. Loeseneriella arnottiana, a member of family Hippocrateaceae, is a climbing shrub used by traditional medicine practitioners. To study the antioxidant activity and radioprotective effect of methanolic root extract of Loeseneriella arnottiana against electron beam radiation induced DNA damage in human lymphocytes. Loeseneriella arnottiana roots were dried and extracted using methanol by solvent extraction method. Antioxidant activity was measured by DPPH method. DNA damage was assessed by comet assay parameters. The lymphocytes were incubated for one hour with two different concentrations 10 μg and 50 μg of root extract before exposure to 2 Gy electron beam radiation. 30 μg of methanolic root extract of Loeseneriella arnottiana exhibited 96% radical scavenging activity comparable to 15 μg of ascorbic acid. In reducing power assay it showed dose dependent increase in absorbance indicating that extract is capable of donating hydrogen atoms. Pretreatment of lymphocytes with 10 μg and 50 μg of root extract before irradiation resulted in reduction in the Comet length, Olive tail moment, percentage of DNA in tail when compared to the radiation control group. Results of this

  16. Hippophae leaf extract (SBL-1) countered radiation induced dysbiosis in jejunum of total body 60Cobalt gamma - irradiated mice

    International Nuclear Information System (INIS)

    Beniwal, C.S.; Madhu Bala

    2014-01-01

    Single dose of SBL-1 administered at the rate 30 mg/kg body weight (b.w.) 30 min prior to whole body 60 Co-gamma-irradiation at lethal dose (10 Gy), rendered >90% survival in comparison to zero survival in the non-SBL-1 treated 60 Co-gamma-irradiated (10 Gy) mice population (J Herbs Spices Med Plants, 2009; 15(2): 203-215). Present study investigated the effect of SBL-1 on jejunal microbiota in lethally irradiated mice. Study was performed with inbred Swiss albino Strain 'A' male mice (age 9 weeks) weighing 28±2 g. The animals were maintained under controlled environment at 26±2℃; 12 h light/dark cycle and offered standard animal food (Golden feed, Delhi) as well as tap water ad libitum. Metagenomic DNA was extracted, purified and quantified from jejunum of the mice. Universal primers (27f and 1492r) were used to amplify the 16S rRNA DNA from the metagenomic DNA. Amplicons were sequenced, vector contamination and chimeras were removed. The sequences (GenBank Accession No: KF681283 to KF681351) were taxonomically classified by using Sequence Match program, Ribosomal Database Project as well as by nucleotide-BLAST (E-value: 10, database: 16S rRNA gene sequences, Bacteria and Archea). Phylogenetic Tree was prepared using MEGA 5.2 package, using maximum likelihood algorithm after sequence alignment by MUSCLE. Thermus aquaticus was used as out-group to construct rooted tree. Branch stability was assessed by bootstrap analysis. Untreated animals and the animals treated with SBL-1 had 100% Lactobacillus; 60 Co gamma-irradiated animals had 55% Cohaesibacter (Alphaproteobacteria); 27% Mycoplasma (Tenericutes) and only 18% Lactobacillus; animals treated with SBL-1 prior to irradiation had 89% Lactobacillus and 11% Clostridium. This study demonstrated that treatment with SBL-1 at radioprotective doses before total body irradiation with lethal dose (10 Gy) countered the jejunal dysbiosis. (author)

  17. IL-18 reduces ultraviolet radiation-induced DNA damage and thereby affects photoimmunosuppression.

    NARCIS (Netherlands)

    Schwarz, Agatha; Maeda, Akira; Ständer, Sonja; Steeg, Harry van; Schwarz, Thomas

    2006-01-01

    UV-induced DNA damage has been recognized as the major molecular trigger for photoimmunosuppression. IL-12 prevents UV-induced immunosuppression via its recently discovered capacity to reduce DNA damage presumably via induction of DNA repair. Because IL-18 shares some biological activities with

  18. The Role of DNA Methylation Changes in Radiation-Induced Transgenerational Genomic Instability and Bystander Effects in cranial irradiated Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Gao, Yinglong; Zhang, Baodong

    Heavy-ion radiation could lead to genome instability in the germline, and therefore to transgenerational genome and epigenome instability in offspring of exposed males. The exact mechanisms of radiation-induced genome instability in directly exposed and in bystander organ remain obscure, yet accumulating evidence points to the role of DNA methylation changes in genome instability development. The potential of localized body-part exposures to affect the germline and thus induce genome and epigenome changes in the progeny has not been studied. To investigate whether or not the paternal cranial irradiation can exert deleterious changes in the protected germline and the offsprings, we studied the alteration of DNA methylation in the shielded testes tissue. Here we report that the localized paternal cranial irradiation results in a significant altered DNA methylation in sperm cells and leads to a profound epigenetic dysregulation in the unexposed progeny conceived 3 months after paternal exposure. The possible molecular mechanisms and biological consequences of the observed changes are discussed. Keywords: Heavy-ion radiation; Transgenerational effect; Genomic Instability Bystander Effects; DNA methylation.

  19. Radiation-induced depression of DNA synthesis in cultured mammalian cells

    International Nuclear Information System (INIS)

    Povirk, L.F.

    1977-01-01

    A 313-nm light source was constructed in order to study the mechanisms by which ultraviolet and ionizing radiations inhibit DNA synthesis. It was found that in CHO, MDBK and HeLa cells, grown for one generation in the DNA sensitizer bromodeoxyuridine (BrdUrd), 313-nm light inhibited DNA synthesis with a pattern similar to that of the effect of x-rays on normal cells. A biphasic dose response curve for inhibition of total synthesis was observed, with a sensitive component representing depression of initiation of new replicons and a resistant component representing interference with elongation of replicons already growing at the time of irradiation. Since the BrdUrd plus 313-nm light treatment produces DNA lesions similar to those produced by x-rays (base damage, strand breaks, crosslinks) these results suggest that the effect of x-rays on DNA synthesis is mediated by DNA damage. In experiments with synchronized cells, it was found that in cells in which about half the chromosomes had incorporated BrdUrd, 313-nm light inhibited replication of the BrdUrd-containing DNA, but had no effect on the replication of the unsubstituted DNA in the same cell. Thus the information that DNA is damaged appears to be propagated along the DNA molecule from the sites of damage to the replication initiation sites as some kind of conformational change, possibly a relaxation of superhelical tension. Target theory calculations suggest that a single DNA lesion prevents the initiation of several adjacent replicons

  20. Repair of endogenous and ionizing radiation-induced DNA damages: mechanisms and biological functions

    International Nuclear Information System (INIS)

    Boiteux, S.

    2002-01-01

    The cellular DNA is continuously exposed to endogenous and exogenous stress. Oxidative stress due to cellular metabolism is the major cause of endogenous DNA damage. On the other hand, ionizing radiation (IR) is an important exogenous stress. Both induce similar DNA damages: damaged bases, abasic sites and strand breakage. Most of these lesions are lethal and/or mutagenic. The survival of the cell is managed by efficient and accurate DNA repair mechanisms that remove lesions before their replication or transcription. DNA repair pathways involved in the removal of IR-induced lesions are briefly described. Base excision repair (BER) is mostly involved in the removal of base damage, abasic sites and single strand breaks. In contrast, DNA double strand breaks are mostly repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). How DNA repair pathways prevent cancer process is also discussed. (author)

  1. Reduction of arsenite-enhanced ultraviolet radiation-induced DNA damage by supplemental zinc

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Karen L.; King, Brenee S.; Sandoval, Monica M.; Liu, Ke Jian; Hudson, Laurie G., E-mail: lhudson@salud.unm.edu

    2013-06-01

    Arsenic is a recognized human carcinogen and there is evidence that arsenic augments the carcinogenicity of DNA damaging agents such as ultraviolet radiation (UVR) thereby acting as a co-carcinogen. Inhibition of DNA repair is one proposed mechanism to account for the co-carcinogenic actions of arsenic. We and others find that arsenite interferes with the function of certain zinc finger DNA repair proteins. Furthermore, we reported that zinc reverses the effects of arsenite in cultured cells and a DNA repair target protein, poly (ADP-ribose) polymerase-1. In order to determine whether zinc ameliorates the effects of arsenite on UVR-induced DNA damage in human keratinocytes and in an in vivo model, normal human epidermal keratinocytes and SKH-1 hairless mice were exposed to arsenite, zinc or both before solar-simulated (ss) UVR exposure. Poly (ADP-ribose) polymerase activity, DNA damage and mutation frequencies at the Hprt locus were measured in each treatment group in normal human keratinocytes. DNA damage was assessed in vivo by immunohistochemical staining of skin sections isolated from SKH-1 hairless mice. Cell-based findings demonstrate that ssUVR-induced DNA damage and mutagenesis are enhanced by arsenite, and supplemental zinc partially reverses the arsenite effect. In vivo studies confirm that zinc supplementation decreases arsenite-enhanced DNA damage in response to ssUVR exposure. From these data we can conclude that zinc offsets the impact of arsenic on ssUVR-stimulated DNA damage in cells and in vivo suggesting that zinc supplementation may provide a strategy to improve DNA repair capacity in arsenic exposed human populations. - Highlights: • Low levels of arsenite enhance UV-induced DNA damage in human keratinocytes. • UV-initiated HPRT mutation frequency is enhanced by arsenite. • Zinc supplementation offsets DNA damage and mutation frequency enhanced by arsenite. • Zinc-dependent reduction of arsenite enhanced DNA damage is confirmed in vivo.

  2. Ionizing Radiation-Induced DNA Damage and Its Repair in Human Cells

    Energy Technology Data Exchange (ETDEWEB)

    Dizdaroglu, Miral

    1999-05-12

    DNA damage in mammalian chromatin in vitro and in cultured mammalian cells including human cells was studied. In the first phase of these studies, a cell culture laboratory was established. Necessary equipment including an incubator, a sterile laminar flow hood and several centrifuges was purchased. We have successfully grown several cell lines such as murine hybridoma cells, V79 cells and human K562 leukemia cells. This was followed by the establishment of a methodology for the isolation of chromatin from cells. This was a very important step, because a routine and successful isolation of chromatin was a prerequisite for the success of the further studies in this project, the aim of which was the measurement of DNA darnage in mammalian chromatin in vitro and in cultured cells. Chromatin isolation was accomplished using a slightly modified procedure of the one described by Mee & Adelstein (1981). For identification and quantitation of DNA damage in cells, analysis of chromatin was preferred over the analysis of "naked DNA" for the following reasons: i. DNA may not be extracted efficiently from nucleoprotein in exposed cells, due to formation of DNA-protein cross-links, ii. the extractability of DNA is well known to decrease with increasing doses of radiation, iii. portions of DNA may not be extracted due to fragmentation, iv. unextracted DNA may contain a significant portion of damaged DNA bases and DNA-protein cross-links. The technique of gas chromatography/mass spectrometry (GC/MS), which was used in the present project, permits the identification and quantitation of modified DNA bases in chromatin in the presence of proteins without the necessity of first isolating DNA from chromatin. This has been demonstrated previously by the results from our laboratory and by the results obtained during the course of the present project. The quality of isolated chromatin was tested by measurement of its content of DNA, proteins, and RNA, by analysis of its protein

  3. Ionizing Radiation-Induced DNA Damage and Its Repair in Human Cells

    International Nuclear Information System (INIS)

    Dizdaroglu, Miral

    1999-01-01

    DNA damage in mammalian chromatin in vitro and in cultured mammalian cells including human cells was studied. In the first phase of these studies, a cell culture laboratory was established. Necessary equipment including an incubator, a sterile laminar flow hood and several centrifuges was purchased. We have successfully grown several cell lines such as murine hybridoma cells, V79 cells and human K562 leukemia cells. This was followed by the establishment of a methodology for the isolation of chromatin from cells. This was a very important step, because a routine and successful isolation of chromatin was a prerequisite for the success of the further studies in this project, the aim of which was the measurement of DNA darnage in mammalian chromatin in vitro and in cultured cells. Chromatin isolation was accomplished using a slightly modified procedure of the one described by Mee ampersand Adelstein (1981). For identification and quantitation of DNA damage in cells, analysis of chromatin was preferred over the analysis of ''naked DNA'' for the following reasons: i. DNA may not be extracted efficiently from nucleoprotein in exposed cells, due to formation of DNA-protein cross-links, ii. the extractability of DNA is well known to decrease with increasing doses of radiation, iii. portions of DNA may not be extracted due to fragmentation, iv. unextracted DNA may contain a significant portion of damaged DNA bases and DNA-protein cross-links. The technique of gas chromatography/mass spectrometry (GC/MS), which was used in the present project, permits the identification and quantitation of modified DNA bases in chromatin in the presence of proteins without the necessity of first isolating DNA from chromatin. This has been demonstrated previously by the results from our laboratory and by the results obtained during the course of the present project. The quality of isolated chromatin was tested by measurement of its content of DNA, proteins, and RNA, by analysis of its protein

  4. Radiosensitive Down syndrome lymphoblastoid lines have normal ionizing-radiation-induced inhibition of DNA synthesis

    International Nuclear Information System (INIS)

    Ganges, M.B.; Robbins, J.H.; Jiang, H.; Hauser, C.; Tarone, R.E.

    1988-01-01

    The extent of X-ray-induced inhibition of DNA synthesis was determined in radiosensitive lymphoblastoid lines from 3 patients with Down syndrome and 3 patients with ataxia telangiectasia (AT). Compared to 6 normal control lines, the 3 AT lines were abnormally resistant to X-ray-induced inhibition of DNA synthesis, while the 3 Down syndrome lines had normal inhibition. These results demonstrate that radiosensitive human cells can have normal X-ray-induced inhibition of DNA synthesis and provide new evidence for the dissociation of radioresistant DNA synthesis. (author). 27 refs.; 1 fig.; 1 tab

  5. Factors influencing heterogeneity of radiation-induced DNA-damage measured by the alkaline comet assay

    International Nuclear Information System (INIS)

    Seidel, Clemens; Lautenschläger, Christine; Dunst, Jürgen; Müller, Arndt-Christian

    2012-01-01

    To investigate whether different conditions of DNA structure and radiation treatment could modify heterogeneity of response. Additionally to study variance as a potential parameter of heterogeneity for radiosensitivity testing. Two-hundred leukocytes per sample of healthy donors were split into four groups. I: Intact chromatin structure; II: Nucleoids of histone-depleted DNA; III: Nucleoids of histone-depleted DNA with 90 mM DMSO as antioxidant. Response to single (I-III) and twice (IV) irradiation with 4 Gy and repair kinetics were evaluated using %Tail-DNA. Heterogeneity of DNA damage was determined by calculation of variance of DNA-damage (V) and mean variance (Mvar), mutual comparisons were done by one-way analysis of variance (ANOVA). Heterogeneity of initial DNA-damage (I, 0 min repair) increased without histones (II). Absence of histones was balanced by addition of antioxidants (III). Repair reduced heterogeneity of all samples (with and without irradiation). However double irradiation plus repair led to a higher level of heterogeneity distinguishable from single irradiation and repair in intact cells. Increase of mean DNA damage was associated with a similarly elevated variance of DNA damage (r = +0.88). Heterogeneity of DNA-damage can be modified by histone level, antioxidant concentration, repair and radiation dose and was positively correlated with DNA damage. Experimental conditions might be optimized by reducing scatter of comet assay data by repair and antioxidants, potentially allowing better discrimination of small differences. Amount of heterogeneity measured by variance might be an additional useful parameter to characterize radiosensitivity

  6. Studies on the Use of Gamma Radiation-Induced for Preparation of Some Modified Resins for the Separation of Some Metal Ions

    International Nuclear Information System (INIS)

    Abo-Zahra, S.F.

    2012-01-01

    The work carried out in the present thesis is based on preparation, characterization and applications of some modified resins such as: poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin), poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin and poly(hydroxamic acid) P(HA) resin. Poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin) was prepared by template polymerization of maleic acid (MA) monomer on poly(acrylamide) P(AAm) hydrogel as a template polymer in the presence of N,N'-methylenebisacrylamide (NMBA) as a crosslinker using gamma radiation-induced technique. Poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin was prepared by template polymerization of acrylic acid (AA) and acrylonitrile (AN) monomers on P(AAm) hydrogel as a template polymer in the presence of NMBA as a crosslinker using gamma radiation-induced technique. The conversion of nitrile group to amidoxime one was carried out by the treatment of the prepared resin with an alkaline solution of hydroxylamine. Poly(hydroxamic acid) P(HA) resin was prepared from the reaction of the corresponding water-soluble P(AAm) previously prepared by gamma radiation-induced with hydroxylamine hydrochloride in an alkaline medium. The functional groups on the prepared polymeric resins were confirmed by using Fourier transform infrared (FTIR) spectra. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) measurements, scanning electron microscopy (SEM) and electron spin resonance (ESR) measurements were performed to evaluate the properties of the prepared polymeric resins, free or complexed with metal ions such as Cu 2+ metal ions.

  7. Deficiency of the DNA repair protein nibrin increases the basal but not the radiation induced mutation frequency in vivo

    International Nuclear Information System (INIS)

    Wessendorf, Petra; Vijg, Jan; Nussenzweig, André; Digweed, Martin

    2014-01-01

    Highlights: • lacZ mutant frequencies measured in vivo in mouse models of radiosensitive Nijmegen Breakage Syndrome. • Spontaneous mutation frequencies are increased in lymphatic tissue due to Nbn mutation. • Single base transitions, not deletions, dominate the mutation spectrum. • Radiation induced mutation frequencies are not increased due to Nbn mutation. - Abstract: Nibrin (NBN) is a member of a DNA repair complex together with MRE11 and RAD50. The complex is associated particularly with the repair of DNA double strand breaks and with the regulation of cell cycle check points. Hypomorphic mutation of components of the complex leads to human disorders characterised by radiosensitivity and increased tumour occurrence, particularly of the lymphatic system. We have examined here the relationship between DNA damage, mutation frequency and mutation spectrum in vitro and in vivo in mouse models carrying NBN mutations and a lacZ reporter plasmid. We find that NBN mutation leads to increased spontaneous DNA damage in fibroblasts in vitro and high basal mutation rates in lymphatic tissue of mice in vivo. The characteristic mutation spectrum is dominated by single base transitions rather than the deletions and complex rearrangements expected after abortive repair of DNA double strand breaks. We conclude that in the absence of wild type nibrin, the repair of spontaneous errors, presumably arising during DNA replication, makes a major contribution to the basal mutation rate. This applies also to cells heterozygous for an NBN null mutation. Mutation frequencies after irradiation in vivo were not increased in mice with nibrin mutations as might have been expected considering the radiosensitivity of NBS patient cells in vitro. Evidently apoptosis is efficient, even in the absence of wild type nibrin

  8. Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

    Directory of Open Access Journals (Sweden)

    Silvia Sterpone

    2010-01-01

    Full Text Available It is well known that ionizing radiation (IR can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER. In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer.

  9. Processing of radiation-induced clustered DNA damage generates DSB in mammalian cells

    International Nuclear Information System (INIS)

    Gulston, M.K.; De Lara, C.M.; Davis, E.L.; Jenner, T.J.; O'Neill, P.

    2003-01-01

    Full text: Clustered DNA damage sites, in which two or more lesions are formed within a few helical turns of the DNA after passage of a single radiation track, are signatures of DNA modifications induced by ionizing radiation in mammalian cell. With 60 Co-radiation, the abundance of clustered DNA damage induced in CHO cells is ∼4x that of prompt double strand breaks (DSB) determined by PFGE. Less is known about the processing of non-DSB clustered DNA damage induced in cells. To optimize observation of any additional DSB formed during processing of DNA damage at 37 deg C, xrs-5 cells deficient in non-homologous end joining were used. Surprisingly, ∼30% of the DSB induced by irradiation at 37 deg C are rejoined within 4 minutes in both mutant and wild type cells. No significant mis-repair of these apparent DSB was observed. It is suggested that a class of non-DSB clustered DNA damage is formed which repair correctly within 4 min but, if 'trapped' prior to repair, are converted into DSB during the lysis procedure of PFGE. However at longer times, a proportion of non-DSB clustered DNA damage sites induced by γ-radiation are converted into DSB within ∼30 min following post-irradiation incubation at 37 deg C. The corresponding formation of additional DSB was not apparent in wild type CHO cells. From these observations, it is estimated that only ∼10% of the total yield of non DSB clustered DNA damage sites are converted into DSB through cellular processing. The biological consequences that the majority of non-DSB clustered DNA damage sites are not converted into DSBs may be significant even at low doses, since a finite chance exists of these clusters being formed in a cell by a single radiation track

  10. Kaempferol protects against gamma radiation-induced mortality and damage via inhibiting oxidative stress and modulating apoptotic molecules in vivo and vitro.

    Science.gov (United States)

    Wang, Jing; Li, Tiejun; Feng, Jingjing; Li, Li; Wang, Rong; Cheng, Hao; Yuan, Yongfang

    2018-04-20

    To investigate the potential protective effect of kaempferol, a representative flavonoid, against radiation induced mortality and injury in vivo and vitro.C57BL/6 male mice and human umbilical venous endothelial cells (HUVECs) were pretreated with kaempferol before radiation. We found that kaempferol can effectively increase 30-day survival rate after 8.5 Gy lethal total body irradiation (TBI). Mice were sacrificed at 7th day after 7 Gy TBI, we found kaempferol against radiation-induced tissues damage, by inhibiting the oxidative stress, and attenuating morphological changes and cell apoptosis. In vitro, kaempferol increased HUVECs cell viability and decrease apoptosis. It also mitigated oxidative stress and restored the abnormal expression of prx-5, Cyt-c, Caspase9 and Caspase3 in mRNA and protein level in HUVECs after radiation. Taken together, it suggests kaempferol can protect against gamma-radiation induced tissue damage and mortality. The present study is the first report of the radioprotective role of kaempferol in vivo and vitro. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Radioadaptive response. Efficient repair of radiation-induced DNA damage in adapted cells

    International Nuclear Information System (INIS)

    Ikushima, Takaji; Aritomi, Hisako; Morisita, Jun

    1996-01-01

    To verify the hypothesis that the induction of a novel, efficient repair mechanism for chromosomal DNA breaks may be involved in the radioadaptive response, the repair kinetics of DNA damage has been studied in cultured Chinese hamster V79 cells with single-cell gel electrophoresis. The cells were adapted by priming exposure with 5 cGy of γ-rays and 4-h incubation at 37C. There were no indication of any difference in the initial yields of DNA double-strand breaks induced by challenging doses from non-adapted cells and from adapted cells. The rejoining of DNA double-strand breaks was monitored over 120 min after the adapted cells were challenged with 5 or 1.5 Gy, doses at the same level to those used in the cytogenetical adaptive response. The rate of DNA damage repair in adapted cells was higher than that in non-adapted cells, and the residual damage was less in adapted cells than in non-adapted cells. These results indicate that the radioadaptive response may result from the induction of a novel, efficient DNA repair mechanism which leads to less residual damage, but not from the induction of protective functions that reduce the initial DNA damage

  12. Compound Poisson Processes and Clustered Damage of Radiation Induced DNA Double Strand Breaks

    International Nuclear Information System (INIS)

    Gudowska-Nowak, E.; Ritter, S.; Taucher-Scholz, G.; Kraft, G.

    2000-01-01

    Recent experimental data have demonstrated that DNA damage induced by densely ionizing radiation in mammalian cells is distributed along the DNA molecule in the form of clusters. The principal constituent of DNA damage are double-strand breaks (DSB) which are formed when the breaks occur in both DNA strands and are directly opposite or separated by only a few base pairs. DSBs are believed to be most important lesions produced in chromosomes by radiation; interaction between DSBs can lead to cell killing, mutation or carcinogenesis. The paper discusses a model of clustered DSB formation viewed in terms of compound Poisson process along with the predictive essay of the formalism in application to experimental data. (author)

  13. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in human keratinocytes and ex vivo skin.

    Science.gov (United States)

    Surjana, Devita; Halliday, Gary M; Damian, Diona L

    2013-05-01

    Nicotinamide (vitamin B3) protects from ultraviolet (UV) radiation-induced carcinogenesis in mice and from UV-induced immunosuppression in mice and humans. Recent double-blinded randomized controlled Phase 2 studies in heavily sun-damaged individuals have shown that oral nicotinamide significantly reduces premalignant actinic keratoses, and may reduce new non-melanoma skin cancers. Nicotinamide is a precursor of nicotinamide adenine dinucleotide (NAD(+)), an essential coenzyme in adenosine triphosphate (ATP) production. Previously, we showed that nicotinamide prevents UV-induced ATP decline in HaCaT keratinocytes. Energy-dependent DNA repair is a key determinant of cellular survival after exposure to DNA-damaging agents such as UV radiation. Hence, in this study we investigated whether nicotinamide protection from cellular energy loss influences DNA repair. We treated HaCaT keratinocytes with nicotinamide and exposed them to low-dose solar-simulated UV (ssUV). Excision repair was quantified using an assay of unscheduled DNA synthesis. Nicotinamide increased both the proportion of cells undergoing excision repair and the repair rate in each cell. We then investigated ssUV-induced cyclobutane pyrimidine dimers (CPDs) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxoG) formation and repair by comet assay in keratinocytes and with immunohistochemistry in human skin. Nicotinamide reduced CPDs and 8oxoG in both models and the reduction appeared to be due to enhancement of DNA repair. These results show that nicotinamide enhances two different pathways for repair of UV-induced photolesions, supporting nicotinamide's potential as an inexpensive, convenient and non-toxic agent for skin cancer chemoprevention.

  14. Seabuckthorn (Hippophae rhamnoides L.) leaf extract ameliorates the gamma radiation mediated DNA damage and hepatic alterations

    International Nuclear Information System (INIS)

    Khan, Amitava; Manna, Krishnendu; Das, Dipesh Kr; Sinha, Mahuya; Kesh, Swaraj Bandhu; Das, Ujjal; Dey, Sanjit; Chinchubose; Banerji, Asoke; Dey, Rakhi Sharma

    2014-01-01

    In vitro assessment showed that H. rhumnoides (HrLE) extract possessed free radical scavenging activities and can protect gamma (γ) radiation induced supercoiled DNA damage. For in vivo study, Swiss albino mice were administered with HrLE (30 mg/kg body weight) for 15 consecutive days before exposing them to a single dose of 5 Gy of γ radiation. HrLE significantly prevented the radiation induced genomic DNA damage indicated as a significant reduction in the comet parameters. The lipid peroxidation, liver function enzymes, expression of phosphorylated NFkB (p65) and IkBα: Ba increased whereas the endogenous antioxidants diminished upon radiation exposure compared to control. Pretreatment of HrLE extract ameliorated these changes. Based on the present results it can be concluded that H. rhamnoides possess a potential preventive element in planned and accidental nuclear exposures. (author)

  15. Radiation-induced DNA damage in halogenated pyrimidine incorporated cells and its correlation with radiosensitivity

    International Nuclear Information System (INIS)

    Watanabe, R.; Nikjoo, H.

    2003-01-01

    Cells with DNA containing 5-halogenated pyrimidines in place of thymidine show significant reductions of slope (Do) and shoulder (Dq) of their radiation survival curves. Similar radiosensitization has also been observed in the yield of DNA strand breaks. The purpose of this study is to obtain an insight into the mechanism of cell lethality by examining the relationship between the spectrum of DNA damage and the cell survival. In this study we estimated the enhancement of strand breaks due to incorporation of halogenated pyrimidine, the complexity of DNA damage and the probability of the initial DNA damage leading to cell inactivation. Monte Carlo track structure methods were used to model and simulate the induction of strand breakage by X-rays. The increase of DNA strand break was estimated by assuming the excess strand break was caused by the highly reactive uracil radicals at the halouracil substituted sites. The assumption of the enhancement mechanism of strand breaks was examined and verified by comparison with experimental data for induction of SSB and DSB. The calculated DNA damage spectrum shows the increase in complexity of strand breaks is due to incorporation of halogenated pyrimidines. The increase in the yield of DSB and cell lethality show similar trend at various degrees of halogenated pyrimidine substitution. We asked the question whether this agreement supports the hypothesis that DSB is responsible for cell lethality? The estimated number of lethal damage from the cell survival using a linear-quadratic model is much less than the initial yield of DSB. This work examines the correlation of cell lethality as a function of frequencies of complex form of double strand breaks

  16. Ionizing radiation-induced DNA injury and damage detection in patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Borrego-Soto, Gissela; Ortiz-Lopez, Rocio; Rojas-Martinez, Augusto, E-mail: arojasmtz@gmail.com, E-mail: augusto.rojasm@uanl.mx [Departamento de Bioquímica y Medicina Molecular, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León (Mexico)

    2015-10-15

    Breast cancer is the most common malignancy in women. Radiotherapy is frequently used in patients with breast cancer, but some patients may be more susceptible to ionizing radiation, and increased exposure to radiation sources may be associated to radiation adverse events. This susceptibility may be related to deficiencies in DNA repair mechanisms that are activated after cell-radiation, which causes DNA damage, particularly DNA double strand breaks. Some of these genetic susceptibilities in DNA-repair mechanisms are implicated in the etiology of hereditary breast/ovarian cancer (pathologic mutations in the BRCA 1 and 2 genes), but other less penetrant variants in genes involved in sporadic breast cancer have been described. These same genetic susceptibilities may be involved in negative radiotherapeutic outcomes. For these reasons, it is necessary to implement methods for detecting patients who are susceptible to radiotherapy-related adverse events. This review discusses mechanisms of DNA damage and repair, genes related to these functions, and the diagnosis methods designed and under research for detection of breast cancer patients with increased radiosensitivity. (author)

  17. Evaluation of the repair efficiency of ionizing radiation induced damage to the DNA in healthy persons and breast cancer patients

    International Nuclear Information System (INIS)

    Nascimento, P.A.; Suzuki, M.F.; Da Silva, M.A.; Oliveira, E.M.; Okazaki, K.

    1999-01-01

    The human population is exposed to the action of several mutagenic agents, as tobacco, alcohol, drugs and ionizing radiation, that cause DNA damages. These damages if do not repaired may lead to consequences of great biological importance as mutations, neoplastic transformation and cellular death. People have differences in the efficiency of DNA repair, an individual with repair deficiency will accumulate much more mutations and cellular damages. The deficiency in the repair ability may be a factor of susceptibility to the development of many types of cancer. The main objective of this work is to study the damage and repair in blood cells of health donors and of breast cancer patients, when submitted to ionizing radiation of 60 Co source and compare the repair capacity of them. For this purpose the comet assay applied 1,3 and 24 hours after the irradiation. The results showed that there are differences in the capacity of repair of the two groups. While the health donors repaired most of the radiation induced damage in 3 hours, the breast cancer patients needed more time that suggests a repair system less efficient. (author)

  18. Study of terahertz-radiation-induced DNA damage in human blood leukocytes

    Energy Technology Data Exchange (ETDEWEB)

    Angeluts, A A; Esaulkov, M N; Kosareva, O G; Solyankin, P M; Shkurinov, A P [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Gapeyev, A B; Pashovkin, T N [Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region (Russian Federation); Matyunin, S N [Section of Applied Problems at the Presidium of the Russian Academy of Sciences, Moscow (Russian Federation); Nazarov, M M [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation); Cherkasova, O P [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2014-03-28

    We have carried out the studies aimed at assessing the effect of terahertz radiation on DNA molecules in human blood leukocytes. Genotoxic testing of terahertz radiation was performed in three different oscillation regimes, the blood leukocytes from healthy donors being irradiated for 20 minutes with the mean intensity of 8 – 200 μW cm{sup -2} within the frequency range of 0.1 – 6.5 THz. Using the comet assay it is shown that in the selected regimes such radiation does not induce a direct DNA damage in viable human blood leukocytes. (biophotonics)

  19. Study of terahertz-radiation-induced DNA damage in human blood leukocytes

    Science.gov (United States)

    Angeluts, A. A.; Gapeyev, A. B.; Esaulkov, M. N.; Kosareva, O. G.; Matyunin, S. N.; Nazarov, M. M.; Pashovkin, T. N.; Solyankin, P. M.; Cherkasova, O. P.; Shkurinov, A. P.

    2014-03-01

    We have carried out the studies aimed at assessing the effect of terahertz radiation on DNA molecules in human blood leukocytes. Genotoxic testing of terahertz radiation was performed in three different oscillation regimes, the blood leukocytes from healthy donors being irradiated for 20 minutes with the mean intensity of 8 - 200 μW cm-2 within the frequency range of 0.1 - 6.5 THz. Using the comet assay it is shown that in the selected regimes such radiation does not induce a direct DNA damage in viable human blood leukocytes.

  20. Common genomic signaling among initial DNA damage and radiation-induced apoptosis in peripheral blood lymphocytes from locally advanced breast cancer patients

    DEFF Research Database (Denmark)

    Henríquez-Hernández, Luis Alberto; Pinar, Beatriz; Carmona-Vigo, Ruth

    2013-01-01

    PURPOSE: To investigate the genomic signaling that defines sensitive lymphocytes to radiation and if such molecular profiles are consistent with clinical toxicity; trying to disclose the radiobiology mechanisms behind these cellular processes. PATIENTS AND METHODS: Twelve consecutive patients...... suffering from locally advanced breast cancer and treated with high-dose hyperfractionated radiotherapy were recruited. Initial DNA damage was measured by pulsed-field gel electrophoresis and radiation-induced apoptosis was measured by flow cytometry. Gene expression was assessed by DNA microarray. RESULTS...

  1. Radiation-induced DNA single-strand scission and its rejoining in spermatogonia and spermatozoa of mouse

    International Nuclear Information System (INIS)

    Ono, T.; Okada, S.

    1977-01-01

    Gamma-ray-induced DNA single-strand scissions and the ability to repair the scissions in spermatogonia from young mice and in spermatozoa from adult mice were studied quantitatively by an alkaline sucrose density-gradient centrifugation method. The average size of DNAs in non-irradiated spermatogonia was 2.6-3.0xx10 8 daltons, similar to those of a spermatid-rich population, and the size of DNA in non-irradiated spermatozoa was 1.2x10 8 daltons. In spermatogonia, the radiosensitivity of DNA was 0.42 single-strand breaks/10 12 daltons of DNA/rad in oxic conditions and only 0.24 under anoxic conditions. In spermatozoa the break efficiency of DNA was 0.22 single-strand breaks/10 12 daltons of DNA/rad under oxic conditions and altered little under anoxic irradiation. The DNA scissions were efficiently repaired in spermatogonia within 10 min, whereas the breaks in spermatozoa were not rejoined at all even after two days of post-irradiation time. The radiosensitivities of DNA, repair capability and non- and/or slowreparable DNA scissions were compared in spermatogonium-rich, spermatid-rich and spermatozoanrich populations

  2. The effect of caffeine and adenine on radiation induced suppression of DNA synthesis, and cell survival

    International Nuclear Information System (INIS)

    Wilcoxson, L.T.; Griffiths, T.D.

    1984-01-01

    Exposure of cultured mammalian cells to ionizing radiation or UV light results in a transient decrease in the rate of DNA synthesis. This depression in synthetic rate may be attenuated or deferred via a post-irradiation treatment with caffeine or adenine. It has been suggested that this attenuation may increase the fixation of damage and, therefore, increase radiation sensitivity. However, it has been previously reported that, for V79 cells treated with caffeine or adenine, no correlation exists between the extent of depression and cell survival. The present investigation expands upon these findings by examining the effect of caffeine or adenine post-irradiation treatment on two cell lines with normal UV sensitivity, mouse 3T3 and CHO AA8 cells, and one UV sensitive cell line, CHO UV5 cells. Both caffeine and adenine have been found to reduce, or delay, the suppression in DNA synthesis in all three cell lines. Surprisingly, caffeine appeared to induced even the UV5 cells to recover DNA synthetic ability. The amount of reduction in suppression of DNA synthesis, however, varies between the different cell lines and no consistent relationship with cell survival has emerged

  3. Molecular Mechanisms of Ultraviolet Radiation-Induced DNA Damage and Repair

    Directory of Open Access Journals (Sweden)

    Rajesh P. Rastogi

    2010-01-01

    Full Text Available DNA is one of the prime molecules, and its stability is of utmost importance for proper functioning and existence of all living systems. Genotoxic chemicals and radiations exert adverse effects on genome stability. Ultraviolet radiation (UVR (mainly UV-B: 280–315 nm is one of the powerful agents that can alter the normal state of life by inducing a variety of mutagenic and cytotoxic DNA lesions such as cyclobutane-pyrimidine dimers (CPDs, 6-4 photoproducts (6-4PPs, and their Dewar valence isomers as well as DNA strand breaks by interfering the genome integrity. To counteract these lesions, organisms have developed a number of highly conserved repair mechanisms such as photoreactivation, base excision repair (BER, nucleotide excision repair (NER, and mismatch repair (MMR. Additionally, double-strand break repair (by homologous recombination and nonhomologous end joining, SOS response, cell-cycle checkpoints, and programmed cell death (apoptosis are also operative in various organisms with the expense of specific gene products. This review deals with UV-induced alterations in DNA and its maintenance by various repair mechanisms.

  4. Radiation-induced oxidative damage to the DNA-binding domain of the lactose repressor

    Czech Academy of Sciences Publication Activity Database

    Gillard, N.; Goffinont, S.; Buré, C.; Davídková, Marie; Maurizot, J. C.; Cadene, M.; Spotheim-Maurizot, M.

    2007-01-01

    Roč. 403, part 3 (2007), s. 463-472 ISSN 0264-6021 R&D Projects: GA MŠk 1P05OC085 Institutional research plan: CEZ:AV0Z10480505 Keywords : ionizing radiation * oxidative damage * DNA binding domain * lac repressor Subject RIV: CE - Biochemistry Impact factor: 4.009, year: 2007

  5. Role of DNA damage repair capacity in radiation induced adaptive response

    International Nuclear Information System (INIS)

    Yuan Dexiao; Pan Yan; Zhao Meijia; Chen Honghong; Shao Cunlin

    2009-01-01

    This work was to explore γ-ray induced radioadaptive response (RAR) in Chinese hamster ovary(CHO) cell lines of different DNA damage repair capacities. CHO-9 cells and the two repair-deficient strains, EM-C11(DNA single strand break repair deficient) and XR-C1(DNA double strand break repair deficient), were irradiated with a priming dose of 0.08 Gy or 0.016 Gy. After 4 or 7 hours, they were irradiated again with a challenging dose of 1 Gy. The micronucleus induction and plating efficiency of the cells were assayed. Under 0.08 Gy priming dose and 4-h interval, just the CHO-9 cells showed RAR, while with the 7-h interval the CHO-9 and EM-C11 showed RAR, but XR-C1 did not. When the cells were pretreated with a lower priming dose of 0.016 Gy in a 4-h time interval, all the three cell lines showed RAR to subsequent 1 Gy irradiation. It can be concluded that RAR is not only related to the priming dose and time interval, but also has close dependence on the ability of DNA damage repair. (authors)

  6. Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.

    Directory of Open Access Journals (Sweden)

    Geoffry N De Iuliis

    Full Text Available BACKGROUND: In recent times there has been some controversy over the impact of electromagnetic radiation on human health. The significance of mobile phone radiation on male reproduction is a key element of this debate since several studies have suggested a relationship between mobile phone use and semen quality. The potential mechanisms involved have not been established, however, human spermatozoa are known to be particularly vulnerable to oxidative stress by virtue of the abundant availability of substrates for free radical attack and the lack of cytoplasmic space to accommodate antioxidant enzymes. Moreover, the induction of oxidative stress in these cells not only perturbs their capacity for fertilization but also contributes to sperm DNA damage. The latter has, in turn, been linked with poor fertility, an increased incidence of miscarriage and morbidity in the offspring, including childhood cancer. In light of these associations, we have analyzed the influence of RF-EMR on the cell biology of human spermatozoa in vitro. PRINCIPAL FINDINGS: Purified human spermatozoa were exposed to radio-frequency electromagnetic radiation (RF-EMR tuned to 1.8 GHz and covering a range of specific absorption rates (SAR from 0.4 W/kg to 27.5 W/kg. In step with increasing SAR, motility and vitality were significantly reduced after RF-EMR exposure, while the mitochondrial generation of reactive oxygen species and DNA fragmentation were significantly elevated (P<0.001. Furthermore, we also observed highly significant relationships between SAR, the oxidative DNA damage bio-marker, 8-OH-dG, and DNA fragmentation after RF-EMR exposure. CONCLUSIONS: RF-EMR in both the power density and frequency range of mobile phones enhances mitochondrial reactive oxygen species generation by human spermatozoa, decreasing the motility and vitality of these cells while stimulating DNA base adduct formation and, ultimately DNA fragmentation. These findings have clear implications

  7. Measurement of radiation-induced damage to DNA at the molecular level

    International Nuclear Information System (INIS)

    Dizdaroglu, M.

    1992-01-01

    The present article describes the potential usefulness of the technique of gas chromatography-mass spectrometry (GC/MS) for chemical characterization and quantification of modifications in DNA and in mammalian chromatin. The aim of the article is to give a concise description of the field rather than an exhaustive review, with the emphasis on the practicalities, limitations, applications and comparison with other techniques. (author)

  8. Direct assay of radiation-induced DNA base lesions in mammalian cells

    International Nuclear Information System (INIS)

    1992-01-01

    Adenine (Ade), 2'-deoxyadenosine (dAdo), 5'-deoxyadenosine monophosphate (dAUT), single stranded poly adenylic acid [poly (dA)], double stranded deoxyadenylic-thymidylic acid [ds poly (dA-T)] and salmon testis DNA were irradiated with 500 Gy under oxic and anoxic conditions. The major damage products were analyzed by BPLC with optical detection and quantitated in terms of the percentage of the adenosine in each model compound found as a specific damage product. Outside of the Ade free base, 8-OH-dAdo was the major oxic damage product from each model compound. The type and quantity of the major damage products depended on the sequence and conformation of the model compounds under anoxic conditions. When dAdo and dAMP were irradiated under anoxic conditions, the major damage product was either the R or S isomer of 8,5'cdAdo and little Ade or α-dAdo was observed. However, when poly(dA), poly(dA-dT), and salmon testis DNA were γ-irradiated under nitrogen, the major deoxyadenosine damage product was identified as the α-anomer of deoxyadenosine. No α-deoxyadenosine was detected after irradiation under oxic conditions. The presence of nucleotides with the α-configuration at the anomeric carbon atom in the DNA chain may have a significant effect on its tertiary structure and possibly modify its biological activity

  9. Radiation-induced free radicals in DNA studied by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Graeslund, A.

    1974-01-01

    Radiation biology aims at an understanding of the effects of radiation on biological material. The studied systems may vary in complexity and size from a whole organism to the molecular constituents of a cell. The observed effects are accordingly varied, from visible somatic effects on the organism to physico-chemical molecular changes. Radiation biophysics may be considered as a specialized branch of radiation biology, dealing with physical aspects of radiation damage, particularly at a molecular or sub-cellular level. The work to be presented here is in the field of radiation biophysics, and concerns physical studies of radiation effects on deoxyribonucleic acid, DNA, the hereditary substance of all living organisms. (author)

  10. A quantitative model of the major pathways for radiation-induced DNA double-strand break repair

    International Nuclear Information System (INIS)

    Belov, O.V.; Krasavin, E.A.; Lyashko, M.S.; Batmunkh, M.; Sweilam, N.H.

    2014-01-01

    We have developed a model approach to simulate the major pathways of DNA double-strand break (DSB) repair in mammalian and human cells. The proposed model shows a possible mechanistic explanation of the basic regularities of DSB processing through the nonhomologous end-joining (NHEJ), homologous recombination (HR), and single-strand annealing (SSA). It reconstructs the time-courses of radiation-induced foci specific to particular repair processes including the major intermediate stages. The model is validated for ionizing radiations of a wide range of linear energy transfer (0.2-236 keV/μm) including a relatively broad spectrum of heavy ions. The appropriate set of reaction rate constants was suggested to satisfy the kinetics of DSB rejoining for the considered types of exposure. The simultaneous assessment of three repair pathways allows one to describe their possible biological relations in response to radiation. With the help of the proposed approach, we reproduce several experimental data sets on γ-H2AX foci remaining in different types of cells including those defective in NHEJ, HR, or SSA functions.

  11. DNA Polymerase Gamma in Mitochondrial DNA Replication and Repair

    Directory of Open Access Journals (Sweden)

    William C. Copeland

    2003-01-01

    Full Text Available Mutations in mitochondrial DNA (mtDNA are associated with aging, and they can cause tissue degeneration and neuromuscular pathologies known as mitochondrial diseases. Because DNA polymerase γ (pol γ is the enzyme responsible for replication and repair of mitochondrial DNA, the burden of faithful duplication of mitochondrial DNA, both in preventing spontaneous errors and in DNA repair synthesis, falls on pol γ. Investigating the biological functions of pol γ and its inhibitors aids our understanding of the sources of mtDNA mutations. In animal cells, pol γ is composed of two subunits, a larger catalytic subunit of 125–140 kDa and second subunit of 35–55 kDa. The catalytic subunit contains DNA polymerase activity, 3’-5’ exonuclease activity, and a 5’-dRP lyase activity. The accessory subunit is required for highly processive DNA synthesis and increases the affinity of pol gamma to the DNA.

  12. Antigenotoxic Effect Against Ultraviolet Radiation-induced DNA Damage of the Essential Oils from Lippia Species.

    Science.gov (United States)

    Quintero Ruiz, Nathalia; Córdoba Campo, Yuri; Stashenko, Elena E; Fuentes, Jorge Luis

    2017-07-01

    The antigenotoxicity against ultraviolet radiation (UV)-induced DNA damage of essential oils (EO) from Lippia species was studied using SOS Chromotest. Based on the minimum concentration that significantly inhibits genotoxicity, the genoprotective potential of EO from highest to lowest was Lippia graveolens, thymol-RC ≈ Lippia origanoides, carvacrol-RC ≈ L. origanoides, thymol-RC > Lippia alba, citral-RC ≈ Lippia citriodora, citral-RC ≈ Lippia micromera, thymol-RC > L. alba, myrcenone-RC. EO from L. alba, carvone/limonene-RC, L. origanoides, α-phellandrene-RC and L. dulcis, trans-β-caryophyllene-RC did not reduce the UV genotoxicity at any of the doses tested. A gas chromatography with flame ionization detection analysis (GC-FID) was conducted to evaluate the solubility of the major EO constituents under our experimental conditions. GC-FID analysis showed that, at least partially, major EO constituents were water-soluble and therefore, they were related with the antigenotoxicity detected for EO. Constituents such as p-cymene, geraniol, carvacrol, thymol, citral and 1,8-cineole showed antigenotoxicity. The antioxidant activity of EO constituents was also determined using the oxygen radical antioxidant capacity (ORAC) assay. The results showed that the antigenotoxicity of the EO constituents was unconnected with their antioxidant activity. The antigenotoxicity to different constituent binary mixtures suggests that synergistic effects can occur in some of the studied EO. © 2017 The American Society of Photobiology.

  13. Modulation of radiation-induced apoptosis and G{sub 2}/M block in murine T-lymphoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Palayoor, S.T.; Macklis, R.M.; Bump, E.A.; Coleman, C.N. [Harvard Medical School, Boston, MA (United States)

    1995-03-01

    Radiation-induced apoptosis in lymphocyte-derived cell lines is characterized by endonucleolytic cleavage of cellular DNA within hours after radiation exposure. We have studied this phenomenon qualitatively (DNA gel electrophoresis) and quantitatively (diphenylamine reagent assay) in murine EL4 T-lymphoma cells exposed to {sup 137}Cs {gamma} irradiation. Fragmentation was discernible within 18-24 h after exposure. It increased with time and dose and reached a plateau after 8 Gy of {gamma} radiation. We studied the effect of several pharmacological agents on the radiation-induced G{sub 2}/M block and DNA fragmentation. The agents which reduced the radiation-induced G{sub 2}/M-phase arrest (caffeine, theobromine, theophylline and 2-aminopurine) enhanced the degree of DNA fragmentation at 24 h. In contrast, the agents which sustained the radiation-induced G{sub 2}/M-phase arrest (TPA, DBcAMP, IBMX and 3-aminobenzamide) inhibited the DNA fragmentation at 24 h. These studies on EL4 lymphoma cells are consistent with the hypothesis that cells with radiation-induced genetic damage are eliminated by apoptosis subsequent to a G{sub 2}/M block. Furthermore, it may be possible to modulate the process of radiation-induced apoptosis in lymphoma cells with pharmacological agents that modify the radiation-induced G{sub 2}/M block, and to use this effect in the treatment of patients with malignant disease. 59 refs., 7 figs.

  14. Gamma radiation-induced conditioned taste aversions in rats: A comparison of the protective effects of area postrema lesions with differing doses of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ossenkopp, K.P.; Giugno, L. (Univ. of Western Ontario, London (Canada))

    1989-10-01

    Lesions which destroy the area postrema (AP) and damage the adjacent nucleus of the solitary tract (NTS) attenuate or abolish conditioned taste aversions (CTA) induced by a variety of pharmacological agents as well as exposure to radiation. In the present experiment, 4 groups of male rats received lesions of AP and 4 groups were given sham lesions. One sham-lesioned and one AP-lesioned group were given a single pairing of 1-hr access to a novel 0.10% sodium saccharin solution followed immediately with exposure to 0, 100, 200, or 400 rad of gamma radiation, respectively. Four days later all groups were given daily two-bottle preference tests (saccharin vs. water) on 4 consecutive days. The sham-lesioned groups exposed to the radiation (100, 200, or 400 rad) developed profound aversions to the saccharin on all test days (p less than 0.001). In contrast, all of the AP-lesioned groups as well as the sham-irradiated (0 rad) sham-lesioned group exhibited strong, comparable (p greater than 0.30) preferences for saccharin. Thus, lesion of AP abolished the radiation-induced CTA at all dose levels of radiation. These results raise the possibility of pharmacological intervention at the level of AP to prevent radiation-induced CTA in cancer patients undergoing radiation therapy.

  15. Ultrasound-induced DNA damage and signal transductions indicated by gammaH2AX

    Science.gov (United States)

    Furusawa, Yukihiro; Fujiwara, Yoshisada; Zhao, Qing-Li; Hassan, Mariame Ali; Ogawa, Ryohei; Tabuchi, Yoshiaki; Takasaki, Ichiro; Takahashi, Akihisa; Ohnishi, Takeo; Kondo, Takashi

    2011-09-01

    Ultrasound (US) has been shown to induce cancer cell death via different forms including apoptosis. Here, we report the potential of low-intensity pulsed US (LIPUS) to induce genomic DNA damage and subsequent DNA damage response. Using the ionizing radiation-induced DNA double-strand breaks (DSBs) as the positive control, we were able to observe the induction of DSBs (as neutral comet tails) and the subsequent formation of gammaH2AX-positive foci (by immunofluorescence detection) in human leukemia cells following exposure to LIPUS. The LIPUS-induced DNA damage arose most likely from the mechanical, but not sonochemical, effect of cavitation, based on our observation that the suppression of inertial cavitation abrogated the gammH2AX foci formation, whereas scavenging of free radical formation (e.g., hydroxyl radical) had no protective effect on it. Treatment with the specific kinase inhibitor of ATM or DNA-PKcs, which can phosphorylate H2AX Ser139, revealed that US-induced gammaH2AX was inhibited more effectively by the DNA-PK inhibitor than ATM kinase inhibitor. Notably, these inhibitor effects were opposite to those with radiation-induced gammH2AX. In conclusion, we report, for the first time that US can induce DNA damage and the DNA damage response as indicated by gammaH2AX was triggered by the cavitational mechanical effects. Thus, it is expected that the data shown here may provide a better understanding of the cellular responses to US.

  16. Gamma radiation-induced mutant of NSIC RC144 with broad-spectrum resistance to bacterial blight

    International Nuclear Information System (INIS)

    Alfonso, A.A.; Avellanoza, E.S.; Miranda, R.T.; Espejo, E.O.; Garcia, N.S.

    2014-01-01

    Mutant lines derived from gamma radiation-treated commercial variety NSIC RC144 were produced and screened for novel resistance to bacterial blight, one of the most serious diseases of rice. Preliminary screening of a bulk M2 population through induced method using race 3 of the pathogen Xanthomonas oryzae pv. oryzae (Xoo) resulted in the selection of 89 resistant plants. Subsequent repeated bacterial blight screenings and generation advance for five seasons resulted in the selection of two highly resistant M7 sister lines whose origin can be traced to a single M2 plant. DNA fingerprinting using 63 genome-wide simple sequence repeat (SSR) markers revealed an identical pattern in these lines. Using the same set of markers, they also exhibited 98% similarity to wild type NSIC RC144 indicating that the resistance is due to mutation and not due to genetic admixture or seed impurity. Two seasons of bacterial blight screening using 14 local isolates representing ten races of Xoo revealed an identical reaction pattern in these lines. The reaction pattern was observed to be unique compared to known patterns in four IRBB isolines (IRBB 4, 5, 7 and 21) with strong resistant reaction to bacterial blight suggesting possible novel resistance. The susceptible reaction in F1 testcrosses using Xoo race 6 and the segregation patterns in two F2 populations that fit with the expected 3 susceptible: 1 resistant ratio (P = 0.4, ns) suggest a single-gene recessive mutation in these lines. These mutants are now being used as resistance donor in the breeding program while further molecular characterization to map and characterize the mutated gene is being pursued

  17. Effect of sublethal doses of gamma radiation on DNA super helicity and survival of human fibroblasts

    International Nuclear Information System (INIS)

    Koceva-Chyla, A.

    1992-01-01

    Effect of sublethal doses of gamma radiation on cell survival and DNA super helicity in human fibroblasts was studied. Cell survival was estimated on the basis the basis of clonal growth of irradiated fibroblasts in monolayer culture in vitro. The nucleoid sedimentation technique was used to study ionizing radiation-induced DNA damage in vivo as well as to examine DNA super helicity. Increased concentrations of ethidium bromine (EB) were used to titrate the DNA super coiling response in non-irradiated cells. This response consisted of a relaxation phase (1-5 μg/ml EB) and rewinding phase (5-20 μg/ml EB). Observed biphasic dependence of sedimentation distance of nucleoid on the concentration of EB suggests the dye altered the amount of DNA super coiling in situ. The degree of DNA super coiling and thus the sedimentation rate of nucleoid in absence of EB was very sensitive to strand break induced in DNA by the doses of gamma radiation employed in the cell survival assay. Doses of 2-8 Gy of gamma radiation induced a dose -dependent reduction in the sedimentation of nucleoid. Loss of negative DNA super coiling was initially rapid (about 30% after the dose of 2 Gy) and then proceeded at a slower rate (about 35% and 48% after the doses of 4 Gy and 8 Gy respectively), indicating a significant relaxation of nucleoid structure at the doses of gamma radiation greater than 4 Gy, at which also significant decrease in fibroblasts survival occurred. Significant loss of negative DNA super coiling within the range of doses of gamma radiation resulting in significant decrease of cell survival suggests that destabilizing effect of radiation on DNA tertiary- and quaternary structures (extensive DNA breaks and relaxation of nucleonic super helicity) disturb normal functions and replications of genomic DNA, in consequence leading to a reproductive death of cells. Considering the sensitivity and simplicity of the method, the nucleoid sedimentation technique might be also a useful tool

  18. Radiation-induced DNA breaks detected by immuno labelling of poly(ADP-ribose) in CHO cells. Standardization by pulsed-field gel electrophoresis

    International Nuclear Information System (INIS)

    Varlet, P.; Bidon, N.; Noel, G.; Averbeck, D.; Salamero, J.; DeMurcia, G.

    1998-01-01

    The poly (ADP-ribose) polymerase is an ubiquitous nuclear protein capable of binding specifically to DNA strand breaks. It synthesizes ADP-ribose polymers proportionally to DNA breaks. The actual method of reference to determine DNA double strand breaks is pulsed-field gel electrophoresis, but this requires many cells. It thus appeared of interest to use poly (ADP-ribos)ylation to follow and estimate γ-ray-induced DNA fragmentation at the level of isolated cells after γ-irradiation in chinese hamster ovary cells (CHO-K1). The results obtained by the immuno-labelling technique of ADP-ribose polymers were compared to those obtained by pulsed-field gel electrophoresis. They show that poly (ADP-ribos)ylation reflects the occurrence of radiation-induced DNA strand breaks. A clear relationship exists between the amount of ADP-ribose polymers detected and DNA double strand breaks after γ-irradiation. (authors)

  19. Differences in inhibition by beta-arabinofuranosyladenine (araA) of radiation induced DNA damage repair in exponentially growing and plateau-phase CHO-cells

    International Nuclear Information System (INIS)

    Iliakis, G.; Seaner, R.

    1988-01-01

    The effect of beta-arabinofuranosyladenine (araA) on the repair of radiation induced DNA damage, as measured by the DNA unwinding technique, was studied in exponentially growing and plateau-phase CHO-cells after exposure to X-rays. Induction of DNA damage by radiation was found to be similar in exponentially growing and plateau-phase cells. In the absence of araA, repair of radiation induced DNA damage proceeded with similar kinetics in exponentially growing and plateau-phase cells. AraA at concentrations between 0-1500 μM inhibited DNA repair both in exponentially growing and in plateau-phase cells. However, the degree of inhibition was significantly higher (by a factor of 3) in plateau-phase cells. A similar degree of repair inhibition by araA was observed in plateau-phase cells treated in their conditioned medium, as well as in plateau-phase cells that were transferred in fresh growth medium just before treatment initiation. These results indicate the importance of biochemical parameters associated with alterations in the growth state of the cells for the inhibitory effect of araA and may help in the elucidation of the molecular mechanism(s) underlying repair inhibition by inhibitors of DNA replication. (orig.)

  20. DNA hybrids suggesting a recombination process repairing radiation-induced DNA double-strand breaks in Ehrlich Ascites tumor cells

    International Nuclear Information System (INIS)

    Barthel, H.R.

    1984-01-01

    The results presented suggest the possibility of repair of DNA double-strand breaks by recombination, at least in the S and G 2 -phases of the cell cycle, in mammalian cells. Further experiments with synchronized cell cultures will have to show whether this process may also occur in the G 1 -phase of the cell cycle. (orig./AJ) [de

  1. Anti-oxidant modulation in response to gamma radiation induced oxidative stress in developing seedlings of Psoralea corylifolia L

    International Nuclear Information System (INIS)

    Jan, Sumira; Parween, Talat; Siddiqi, T.O.; Mahmooduzzafar

    2012-01-01

    The seeds of Psoralea corylifolia L., an important medicinal herb in Indian and Chinese Pharmacopeia were exposed to gamma rays (2.5, 5, 10, 15 and 20 kGy) from Co 60 source at dose rate of 1.65 kGy h −1 . Enzymatic and non-enzymatic anti-oxidant responses were verified according to the developmental stages and gamma dose applied. Plants grown from seeds exposed to higher gamma doses exhibit higher activity of the antioxidants such as [Ascorbate peroxidase (APX, 1.11.1.1), superoxide dismutase (SOD, 1.15.1.1), glutathione reductase (GR, 1.6.4.2) and MDA content till flowering and declined thereafter. In contrast, CAT (1.11.1.6) activity declined in dose and age dependent manner. The correlation of gamma dose applied and oxidative stress was inferred from the increased enzymes activities and depression in total glutathione pool in seedlings developed from irradiated seeds. Nevertheless, the maintenance of high anti-oxidant capacity, psoralen accumulation seems to be an important strategy during acclimation of P. corylifolia to gamma radiation stress. Pronounced accumulation of psoralen following 15 and 20 kGy at post-flowering stage where oxidative stress is triggered modulates lipid peroxidation and proline accumulation. Further, in psoralen producing plants an increase in psoralen content can be used as a biomarker which specifies plant is under stress. - Highlights: ► This manuscript points for the first time over expression of antioxidant enzymes to variable doses of gamma rays with corresponding increase in psoralen content in Psoralea corylifolia L. ► Decline in lipid peroxidation and proline accumulation was concomitant with psoralen increment describing the potential of Psoralen as antioxidant. ► Survival of plants following higher dosage of gamma-radiation (15 and 20 kGy) describes the radio resistivity of Psorelea seeds.

  2. Radioprotective action of WR-1065 on radiation-induced DNA strand breaks in cultured Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Murray, D.; VanAnkeren, S.C.; Milas, L.; Meyn, R.E.

    1988-01-01

    We have examined the radioprotective effect of WR-1065 on cultured Chinese hamster ovary cells. The effects of the drug on the induction and rejoining of gamma-ray-induced DNA single-strand breaks (SSBs) and double-strand breaks (DSBs) were measured using alkaline (pH 12.1) and neutral (pH 7.0) elution, respectively. Molecular protection factors (PFs) calculated from these data allowed us to determine whether the degree of modification of strand breakage accurately predicted the PFs measured using the biological end point of cell survival. The drug did protect against the induction of both SSBs and DSBs, although to an extent that did not appear to fully account for the degree of radioprotection in terms of cell killing measured under identical conditions. It is therefore unlikely that radioprotection by WR-1065 occurs simply as a consequence of a general lowering of all types of gamma-ray-induced DNA lesions, and it is possible that the drug could differentially protect against the induction of subsets of these DNA lesions. The rate of SSB rejoining was retarded following preirradiation treatment of cells with WR-1065, but there was no effect on DSB rejoining. Postirradiation treatment with WR-1065 also appeared to retard SSB rejoining but without an accompanying effect on either DSB rejoining or cell survival; however, this effect was largely reversed by the addition of catalase and was, therefore, probably a result of H 2 O 2 generated by autoxidation of the drug. Based on these observations, it would appear that the molecular actions of aminothiol radioprotective compounds that lead to reduced cell killing are much more complex than previously thought

  3. Impact of alpha-, gamma-, and delta-tocopherol on the radiation induced oxidation of rapeseed oil triacylglycerols

    Energy Technology Data Exchange (ETDEWEB)

    Braunrath, Robert; Isnardy, Bettina; Solar, Sonja, E-mail: sonja.solar@univie.ac.at; Elmadfa, Ibrahim

    2010-07-15

    Gamma-irradiation (doses: 2, 4, 7, and 10 kGy) was used as oxidation tool to study the antioxidant effects of alpha-, gamma-, and delta-tocopherol (enrichments 500-5000 ppm) in purified rapeseed oil triacylglycerols (RSOTG). Fatty acid composition, tocopherol degradation, primary (conjugated dienes (CD) and peroxide value (POV)) and secondary (p-anisidine value) oxidation products were chosen as test parameters. Fatty acid composition did not change. While secondary oxidation products could not be found in the irradiated samples, the POVs and CDs showed a significant, dose-dependent increase. alpha-Tocopherol did not inhibit the formation of peroxides, whereas gamma- and delta-tocopherol reduced the POVs by more than 30%. No uniform effect of the different tocopherol concentrations at the particular doses could be established. The influence of the individual tocopherols on the CD formation was not pronounced. The degradation of the tocopherols decreased with increasing concentration. None of the tocopherols showed a prooxidant effect.

  4. Radiation induced strand breaks and time scale for repair of broken strands in superinfecting phage lambda DNA in Escherichia coli lysogenic for lambda

    International Nuclear Information System (INIS)

    Johansen, I.; Boye, E.; Brustad, T.

    1975-01-01

    The production of the first radiation induced break in covalent lambda DNA molecules in pol + and pol A 1 lysogenic host cells was measured after exposure to electrons from a linear accelerator and transfer to alkaline detergent within 100 ms from the onset of irradiation. The results revealed the presence of an oxygen effect in DNA strand breakage. In both pol + and pol A 1 host cells the rate of production in nitrogen was 1.2x10 -12 DNA single strand breaks per rad per dalton as compared to 5x10 -12 in oxygen. The yields of strand breaks in lambda DNA in pol + host cells under oxygenated or anoxic conditions are independent of whether the cells are irradiated in buffer at room temperature, in buffer at ice temperature, or in growth medium at 37 0 C. These results indicate that enzymic repair of DNA strand breaks before analysis is insignificant in these experiments. The presence of an oxygen effect in DNA strand breakage under these conditions suggest that an actual difference exists between initial number of breaks produced in nitrogen and in oxygen. The kinetics of rejoining of broken molecules under optimal growth conditions was measured by incubating the irradiated host cells prior to lysis. In pol + host cells 50% of the lambda DNA molecules broken in presence of oxygen are rejoined within 10 to 20 seconds of incubation. A significantly lower recovery is seen in pol + host cells after irradiation in nitrogen. The rejoining of broken lambda DNA strands in pol A 1 host cells is impaired after irradiation in presence of oxygen as well as under anoxia. These results show that DNA polymerase I is needed for the rapid rejoining of radiation induced strand breaks in the DNA, and that oxygen promoted strand breaks are more easily rejoined than are those produced in nitrogen. (author)

  5. Effectiveness of Aloe vera leaf extract against low level exposure to gamma radiation induced injury in intestinal mucosa of Swiss mice

    International Nuclear Information System (INIS)

    Gehlot, Prashasnika; Saini, M.R.

    2004-01-01

    Full Text: Human beings can not deny the presence of all sorts of incoming radiations, which are detrimental to life. The small intestine represents one of the major dose limiting normal tissues in radiotherapy because of its high radio sensitivity. The purpose of this study was to determine the effects of Aloe vera, a potential radioprotector. Radioprotective efficacy of aloe vera leaf extract in intestinal mucosa in mice (1 g/kg body weight/day) was studied from 6h to day 20 after gamma irradiation (0.5 Gy(. Villus height, goblet cells/villus section, total cells are good parameters for the assessment of radiation damage. The mice selected from inbreed colony were divided into two groups. The first group was given Aloe vera extract orally for 15 consecutive days and served as experimental group. On 15th day, after 30 min of above treatment animals of both the groups were exposed to 0.5 Gy gamma irradiation and autopsied on 6, 12, 24 h and 5, 10, 20 days. Aloe vera pretreatment resulted in a significant increase (p<0.001) in villus height, total cells whereas globlet cells showed a significant decrease (p<0.001) from respective irradiated controls at each autospy day. The results suggest that Aloe vera pretreatment provides protection against radiation-induced alterations in intestinal mucosa of Swiss mice

  6. Radiation-induced DNA damage in tumors and normal tissues. II. Influence of dose, residual DNA damage and physiological factors in oxygenated cells

    International Nuclear Information System (INIS)

    Zhang, H.; Wheeler, K.T.

    1994-01-01

    Detection and quantification of hypoxic cells in solid tumors is important for many experimental and clinical situations. Several laboratories, including ours, have suggested that assays which measure radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) might be used to detect or quantify hypoxic cells in tumors and normal tissues. Recently, we demonstrated the feasibility of using an alkaline elution assay that measures strand breaks and DPCs to detect and/or quantify hypoxic cells in tissues. For this approach to be valid, DPCs must not be formed to any great extent in irradiated oxygenated cells, and the formation and repair of strand breaks and DPCs in oxygenated cells must not be modified appreciably by physiological factors (e.g., temperature, pH and nutrient depletion) that are often found in solid tumors. To address these issues, two sets of experiments were performed. In one set of experiments, oxygenated 9L cells in tissue culture, subcutaneous 9L tumors and rat cerebella were irradiated with doses of 15 or 50 Gy and allowed to repair until the residual strand break damage was low enough to detect DPCs. In another set of experiments, oxygenated exponentially growing or plateau-phase 9L cells in tissue culture were irradiated with a dose of 15 Gy at 37 or 20 degrees C, while the cells were maintained at a pH of either 6.6 or 7.3. DNA-protein crosslinks were formed in oxygenated cells about 100 times less efficiently than in hypoxic cells. In addition, temperature, pH, nutrient depletion and growth phase did not appreciably alter the formation and repair of strand breaks or the formation of DPCs in oxygenated 9L cells. These results support the use of this DNA damage assay for the detection and quantification of hypoxic cells in solid tumors. 27 refs., 5 tabs

  7. The Degree of Radiation-Induced DNA Strand Breaks Is Altered by Acute Sleep Deprivation and Psychological Stress and Is Associated with Cognitive Performance in Humans.

    Science.gov (United States)

    Moreno-Villanueva, Maria; von Scheven, Gudrun; Feiveson, Alan; Bürkle, Alexander; Wu, Honglu; Goel, Namni

    2018-03-27

    Sleep deprivation is associated with impaired immune responses, cancer, and morbidity and mortality, and can degrade cognitive performance, although individual differences exist in such responses. Sleep deprivation induces DNA strand breaks and DNA base oxidation in animals, and psychological stress is associated with increased DNA damage in humans. It remains unknown whether sleep deprivation or psychological stress in humans affects DNA damage response from environmental stressors, and whether these responses predict cognitive performance during sleep deprivation. Sixteen healthy adults (ages 29-52;mean age±SD, 36.4±7.1 years;7 women) participated in a 5-day experiment involving two 8 hour time-in-bed [TIB] baseline nights, followed by 39 hours total sleep deprivation (TSD), and two 8-10 hour TIB recovery nights. A modified Trier Social Stress Test was conducted on the day after TSD. Psychomotor Vigilance Tests measured behavioral attention. DNA damage was assessed in blood cells collected at 5 time points, and blood cells were irradiated ex-vivo. TSD, alone or in combination with psychological stress, did not induce significant increases in DNA damage. By contrast, radiation-induced DNA damage decreased significantly in response to TSD, but increased back to baseline when combined with psychological stress. Cognitively-vulnerable individuals had more radiation-induced DNA strand breaks before TSD, indicating their greater sensitivity to DNA damage from environmental stressors. Our results provide novel insights into the molecular consequences of sleep deprivation, psychological stress, and performance vulnerability. They are important for situations involving sleep loss, radiation exposure and cognitive deficits, including cancer therapy, environmental toxicology, and space medicine.

  8. Protective effect of vitamins C and E on Gamma radiation induced Genetic injuries in male mice germ cells

    International Nuclear Information System (INIS)

    Anwar, W.A.; El-Daway, H.A.E.; Tawfik, S.S.M.

    1999-01-01

    The effects of vitamins C and E on meiotic chromosomal metaphase-8 at diakinesis of the mouse to 3 Gy of whole body gamma- irradiation were studied. These vitamins were injected intraperitoneally as acute doses 2 hr before irradiation. Both vitamins significantly reduced the frequencies of chromosomal aberration in spermatic germ cells. The protective effect of vitamin E was greater than that afforded by vitamin C. A combined treatment of both vitamins resulted in additional protection over that offered by each vitamine alone. In all animal groups the most frequent aberration found was translocation in the from of either ring four (R IV) or chain four (C IV). The percentage of each or them was significantly increased in male mice sacrificed after 15 days post-irradiation. Other types of aberrations as autosomal univalent, X-Gamma univalent and polyploidy were rarely present

  9. Measurement of Cerenkov Radiation Induced by the Gamma-Rays of Co-60 Therapy Units Using Wavelength Shifting Fiber

    Directory of Open Access Journals (Sweden)

    Kyoung Won Jang

    2014-04-01

    Full Text Available In this study, a wavelength shifting fiber that shifts ultra-violet and blue light to green light was employed as a sensor probe of a fiber-optic Cerenkov radiation sensor. In order to characterize Cerenkov radiation generated in the developed wavelength shifting fiber and a plastic optical fiber, spectra and intensities of Cerenkov radiation were measured with a spectrometer. The spectral peaks of light outputs from the wavelength shifting fiber and the plastic optical fiber were measured at wavelengths of 500 and 510 nm, respectively, and the intensity of transmitted light output of the wavelength shifting fiber was 22.2 times higher than that of the plastic optical fiber. Also, electron fluxes and total energy depositions of gamma-ray beams generated from a Co-60 therapy unit were calculated according to water depths using the Monte Carlo N-particle transport code. The relationship between the fluxes of electrons over the Cerenkov threshold energy and the energy depositions of gamma-ray beams from the Co-60 unit is a near-identity function. Finally, percentage depth doses for the gamma-ray beams were obtained using the fiber-optic Cerenkov radiation sensor, and the results were compared with those obtained by an ionization chamber. The average dose difference between the results of the fiber-optic Cerenkov radiation sensor and those of the ionization chamber was about 2.09%.

  10. Influence of cell cycle phase on radiation-induced cytotoxicity and DNA damage in human colon cancer (HT29) and Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Tang, H.; Davis, M.A.; Strickfaden, S.M.; Maybaum, J.; Lawrence, T.S.

    1994-01-01

    We have previously shown that fluorodeoxyuridine (FdUrd) radiosensitizes HT29 human colon carcinoma cells. Since treatment with FdUrd arrests cells at the G 1 /S-phase interface, a condition associated with increased radiation sensitivity in some cells, it seemed possible that redistribution of cells in the phases of the cell cycle might account for FdUrd-mediated radiosensitization. To begin to test this, HT29 cells were separated by centrifugal elutriation according to cell cycle phase and assessed for radiosensitivity, using a clonogenic assay, and radiation-induced DNA damage, using pulsed-field gel electrophoresis. We found that all of the elutriated fractions (which contained cells enriched in G 1 , G 1 /early S, mid to late S or G 2 /M phase) had the same radiation sensitivity and expressed a similar extent of radiation-induced DNA damage. To determine if the techniques used in this study could detect differences between the radiation sensitivity of cells in different phases of the cell cycle, analogous experiments were carried out using Chinese hamster ovary (CHO) cells. In contrast with the results of experiments with HT29 cells, but in agreement with previous studies, CHO cells separated under the same conditions as were used for HT29 cells showed a marked dependence on cell age of both clonogenic survival and radiation-induced DNA damage. Thus, within the limitations of the purity of separation obtained using elutriation, the radiation sensitivity of HT29 cells does not vary substantially as a function of cell cycle phase. Therefore, it seems unlikely that cell cycle redistribution alone explains the radiation sensitivity produced by exposure to FdUrd. 20 refs., 4 figs., 1 tab

  11. Adaptive Response to ionizing Radiation Induced by Low Doses of Gamma Rays in Human Lymphoblastoid Cell Lines

    International Nuclear Information System (INIS)

    Seong, Jin Sil; Suh, Chang Ok; Kim, Gwi Eon

    1994-01-01

    When cells are exposed to low doses of a mutagenic or clastogenic agents, they often become less sensitive to the effects of a higher does administered subsequently. Such adaptive responses were first described in Escherichia coli and mammalian cells to low doses of an alkylating agent. Since most of the studies have been carried out with human lymphocytes, it is urgently necessary to study this effect in different cellular systems. Its relation with inherent cellular radiosensitivity and underlying mechanism also remain to be answered. In this study, adaptive response by 1 cGy of gamma rays was investigated in three human lymphoblastoid cell lines which were derived from ataxia telangiectasia homozygote, ataxia telangiectasia heterozygote, and normal individual. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher does (50 cGy). The expression of this adaptive response was similar among three cell lines despite of their different radiosensitivity. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the tested cell lines. Therefore it is suggested that the adaptive response can be observed in human lymphoblastoid cell lines. Which was first documented through this study. The expression of adaptive response was similar among the cell lines regardless of their radiosensitivity. The elimination of the adaptive response by 3-aminobenzamide is consistent with the proposal that this adaptive response is the result of the induction of a certain chromosomal repair mechanism

  12. Therapeutic Effect of Taurine on Gamma Radiation Induced Genetic Injuries in Germ Cells of Male Mice and Their Male Offspring

    International Nuclear Information System (INIS)

    El-Dawy, H.A.; Tawfik, S.S.; El-Khafif, M.A.; Ragab, M.H.

    2005-01-01

    The efficiency of taurine therapy for treatment of male mice exposed to a dose of (3 Gy) whole body gamma irradiation and their male offspring was studied after administration taurine 1% in drinking water post irradiation. Administration of taurine therapy resulted in a significant decrease in the effect of irradiation on chromosomal aberrations in irradiated animals and their male offspring. The efficiency of taurine as radio therapeutic agent is greatly dependent on its chemical properties as strong oxidants scavenger and biological activities as osmoregulator and membrane stabilizer. The probable mechanism of taurine therapy was discussed

  13. Gamma-radiation-induced absorption in doubly doped PbWO sub 4 :Mo,Y crystals

    CERN Document Server

    Sulc, M; Bohácek, P; Nejezchleb, K; Jarolímek, O; Vognar, M

    2002-01-01

    The set of Mo and (Mo,Y) doped PbWO sub 4 scintillating crystals was irradiated 30 min by a homogeneous gamma-radiation field, produced in the irradiation of tungsten target by 21 MeV electron beam from the microtrone accelerator. The induced absorption spectra were measured on-line, i.e. during the irradiation and after switching-off the machine with a sampling rate of 10 s for the dose rates of about 0.17 Gy/min. The results show a clear effect of the doped ions in PWO crystals on the spectra and kinetics of both colour centres formation and recovery processes. The induced absorption build-up and recovery time dependences at fixed wavelength are approximated by a simple model and quantitative parameters are extracted and discussed.

  14. Radiation induced pesticidal microbes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Yup; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.; Lim, D. S

    2001-01-01

    To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants.

  15. Radiation induced pesticidal microbes

    International Nuclear Information System (INIS)

    Kim, Ki Yup; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.; Lim, D. S.

    2001-01-01

    To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants

  16. Effects of expression level of DNA repair-related genes involved in the NHEJ pathway on radiation-induced cognitive impairment

    International Nuclear Information System (INIS)

    Zhang Liyuan; Chen Liesong; Sun Rui; Ji Shengjun; Ding Yanyan; Wu Jia; Tian Ye

    2013-01-01

    Cranial radiation therapy can induce cognitive decline. Impairments of hippocampal neurogenesis are thought to be a paramountly important mechanism underlying radiation-induced cognitive dysfunction. In the mature nervous system, DNA double-strand breaks (DSBs) are mainly repaired by non-homologous end-joining (NHEJ) pathways. It has been demonstrated that NHEJ deficiencies are associated with impaired neurogenesis. In our study, rats were randomly divided into five groups to be irradiated by single doses of 0 (control), 0 (anesthesia control), 2, 10, and 20 Gy, respectively. The cognitive function of the irradiated rats was measured by open field, Morris water maze and passive avoidance tests. Real-time PCR was also used to detect the expression level of DNA DSB repair-related genes involved in the NHEJ pathway, such as XRCC4, XRCC5 and XRCC6, in the hippocampus. The influence of different radiation doses on cognitive function in rats was investigated. From the results of the behavior tests, we found that rats receiving 20 Gy irradiation revealed poorer learning and memory, while no significant loss of learning and memory existed in rats receiving irradiation from 0-10 Gy. The real-time PCR and Western blot results showed no significant difference in the expression level of DNA repair-related genes between the 10 and 20 Gy groups, which may help to explain the behavioral results, id est (i.e.) DNA damage caused by 0-10 Gy exposure was appropriately repaired, however, damage induced by 20 Gy exceeded the body's maximum DSB repair ability. Ionizing radiation-induced cognitive impairments depend on the radiation dose, and more directly on the body's own ability to repair DNA DSBs via the NHEJ pathway. (author)

  17. Radiation-induced reactions of Cl-, CO32-, and Br- in seawater, - Model calculation of gamma radiolysis of seawater

    International Nuclear Information System (INIS)

    Hata, Kuniki; Hanawa, Satoshi; Kasahara, Shigeki; Muroya, Yusa; Katsumura, Yosuke

    2012-09-01

    Gamma-radiolysis of seawater has been simulated to estimate the concentrations of radiolysis products. Although gas products such as H 2 , O 2 and H 2 O 2 in irradiated pure water quickly attain the steady state with very low concentrations, the products in seawater monotonically increase with dose. It was found that H 2 is produced almost linearly with dose, and corresponding G-value was 4.4 x 10 -8 mol J -1 . As similar result was obtained from the calculation of 8 x 10 -4 mol dm -3 NaBr solution, the origin of the linear increase in seawater was attributable to be the reactions of Br - . According to the sensitivity analysis, three reactions, 1: Br - + ·OH → BrOH· - , 2: BrOH· - → Br - + ·OH, and 3: BrOH· - → Br· + OH - , determined the concentrations of the products. The presence of Cl - and HCO 3 - in seawater hardly affected the concentrations of the radiolysis products. Oxyanions derived from Cl - and Br - were not obtained at observable concentration. (authors)

  18. Development of analyzing system for gene functions of nerve growth factor using {gamma}-radiation induced mutants of Oryzias latipes

    Energy Technology Data Exchange (ETDEWEB)

    Araki, Kazuo; Nagoya, Hiroyuki; Okamoto, Hiroyuki [National Research Inst. of Aquaculture, Mie (Japan)

    1999-02-01

    Oryzias latipes mutants that have abnormalities in the nervous system were screened with an aim to develop a model system to investigate the functions of nerve growing factor gene. When male O. latipes was exposed to {gamma}-ray at a dose of 4.5 to 5.0 Gy, its mutants were most effectively produced. Then, F{sub 2} pairs that might produce offspring with abnormalities in the brain, chorda and tail were selected and cultured successively. The embryos of thus obtained mutants, nt and ut were histologically observed at various stages of their developments and these mutants were found to have abnormalities in the chorda. Then, the expressions of Brachury and HNF3{beta} genes, which possibly control the expression of nerve growth factor gene and closely mediate the embryogenesis were investigated in the chorda and the mesoderm of these mutants by in situ hybridization method. Brachury gene in nt mutant as well as the wild strain was expressed in the region of the tail end, whereas HNF3{beta} gene of nt was not expressed in the chordal end and its adjacent mesoderm. This suggests that the gene of growth factor of which expression is induced by HNF3{beta}, might be inactive in the caudal region of the embryo. When these mutants with abnormalities in caudal formation were crossed each other, any abnormality was not observed in the chordal formation of the offspring. Therefore, it was concluded that the abnormalities in the chordal formation of these mutants might be caused by a mutation at different genes. (M.N.)

  19. Amelioration of radiation induced DNA damage and biochemical alterations by Punica Granatum (L) extracts and synthetic ellagic acid in Swiss albino mice

    International Nuclear Information System (INIS)

    Satheesh Kumar Bhandary, B.; Sharmila, K.P.; Suchetha Kumari, N.; Vadisha Bhat, S.; Sherly, Sharmila; Sanjeev, Ganesh

    2013-01-01

    Radiation therapy has been used in cancer treatment for many decades; Although effective in killing tumor cells, ROS produced in radiotherapy threaten the integrity and survival of surrounding normal cells. ROS are scavenged by radioprotectors before they can interact with biochemical molecules, thus reducing harmful effects of radiation. The pomegranate, Punica granatum L., an ancient, mystical, and highly distinctive fruit, is the predominant member of the Punicaceae family. It is used in several systems of medicine for a variety of ailments. The objective of the present study was to investigate the protective effects of ethanolic extracts of pomegranate whole fruit (EPWF) and seeds (EPS) and Synthetic Ellagic acid (EA) against Electron Beam Radiation (EBR) induced DNA damage and biochemical alterations in Swiss Albino mice. The extracts and synthetic compound were assessed for its radical scavenging property by DPPH radical scavenging and Ferric Reducing Antioxidant Power assays. The animals were treated with 200 mg/kg body wt. of pomegranate extracts and Ellagic acid for 15 days before exposure to 6 Gy of EBR. Radiation induced DNA damage was assessed by comet assay in the peripheral blood lymphocytes of mice. The biochemical estimations were carried out in the serum and RBC lysate of the animals. The plant extracts and synthetic compound exhibited good radical scavenging and reducing properties.The pretreated animals before irradiation caused a reduction in the comet length, olive tail moment, % DNA in tail when compared to irradiated group. The biochemical parameters such as lipid peroxidation was significantly depleted in the treated groups when compared to irradiated group followed by significant elevation in reduced glutathione. Our findings indicate the ameliorating effects of pomegranate extracts and synthetic ellagic acid on radiation induced DNA damage and biochemical changes in mice may be due to its free radical scavenging and increased antioxidant

  20. Influence of Gamma Irradiation on DNA Methylation in Liver of Male Rats and their Offspring

    Directory of Open Access Journals (Sweden)

    M. Kožurková

    2007-01-01

    Full Text Available In the present work, the influence of gamma radiation (3 Gy on DNA methylation in slowly proliferating liver tissue of adult male rats and their offspring was studied. Total methylation of DNA was determined on the basis of presence of 5-methylcytosine at the inner cytosine of the C-C-G-G sequence by using restriction enzymes, endonuclease Msp I and its isoschisomer Hpa II. It was found that in the liver of control animals, molecular weight distribution of both Msp I and Hpa II digestion products of DNA and the level of DNA methylation were influenced by age mainly between the 3rd and the 7th days of life. At this time, significant difference was found especially in products of cleavage with enzyme Msp I, where an increase in DNA fragments of medium molecular weight (1 - 7 kb occurred. The changes in the molecular weight distribution of DNA digestion products in the offspring of control rats were accompanied by an increase in the level of total DNA methylation from 29.8% to 67%. In the offspring of irradiated males, the level of DNA methylation was higher in comparison with the offspring of non-irradiated control males, especially on the 3rd day after birth. We suppose that this finding is conjoined with a transgeneration transfer of radiation-induced genome damage.

  1. Protective effect of curcumin and its analog on γ-radiation induced DNA damage and lipid peroxidation in cultured human lymphocytes and isolated rat hepatocytes in vitro

    International Nuclear Information System (INIS)

    Menon, Venugopal P.

    2007-01-01

    Ionizing radiation is known to induce oxidative stress through generation of reactive oxygen species (ROS) resulting in an imbalance of the pro-oxidant and antioxidant status in the cells, which is suggested to culminate in cell death. The present work was aimed to evaluate the radioprotective effect of curcumin and its analog on γ-radiation induced toxicity in cultured human lymphocytes and rat hepatocytes. Hepatocytes were isolated from the liver of rats by collagenase perfusion. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analyzed by comet assay, cytokinesis blocked micro nucleus assay, dicentric aberrations and translocation frequency. Cell cycle distribution and measurement of the percentage of apoptotic cells were performed by flow cytometry analysis. To investigate whether the dietary agents like curcumin and its analog have a role on cell cycle regulation, we analyzed the changes in cell cycle profiles by using fluorescence activated cell sorter. The increase in the severity of DNA damage was observed with the increase dose (1, 2 and 4 Gy) of γ-radiation in cultured lymphocytes and hepatocytes. TBARS were increased significantly, whereas the levels of GSH and antioxidant enzymes were significantly decreased in γ-irradiated hepatocytes and lymphocytes. On pretreatment with curcumin and its analog (1, 5 and 10 μg/ml) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes were increased significantly along with the levels of GSH. The maximum protection of hepatocytes and lymphocytes was observed at 10 μg/ml curcumin and 5 μg/ml curcumin analog pretreatment. Thus, pretreatment with curcumin and its analog helps in protecting the normal hepatocytes and lymphocytes against γ-radiation induced cellular

  2. Celecoxib Induced Tumor Cell Radiosensitization by Inhibiting Radiation Induced Nuclear EGFR Transport and DNA-Repair: A COX-2 Independent Mechanism

    International Nuclear Information System (INIS)

    Dittmann, Klaus H.; Mayer, Claus; Ohneseit, Petra A.; Raju, Uma; Andratschke, Nickolaus H.; Milas, Luka; Rodemann, H. Peter

    2008-01-01

    Purpose: The purpose of the study was to elucidate the molecular mechanisms mediating radiosensitization of human tumor cells by the selective cyclooxygenase (COX)-2 inhibitor celecoxib. Methods and Materials: Experiments were performed using bronchial carcinoma cells A549, transformed fibroblasts HH4dd, the FaDu head-and-neck tumor cells, the colon carcinoma cells HCT116, and normal fibroblasts HSF7. Effects of celecoxib treatment were assessed by clonogenic cell survival, Western analysis, and quantification of residual DNA damage by γH 2 AX foci assay. Results: Celecoxib treatment resulted in a pronounced radiosensitization of A549, HCT116, and HSF7 cells, whereas FaDu and HH4dd cells were not radiosensitized. The observed radiosensitization could neither be correlated with basal COX-2 expression pattern nor with basal production of prostaglandin E2, but was depended on the ability of celecoxib to inhibit basal and radiation-induced nuclear transport of epidermal growth factor receptor (EGFR). The nuclear EGFR transport was strongly inhibited in A549-, HSF7-, and COX-2-deficient HCT116 cells, which were radiosensitized, but not in FaDu and HH4dd cells, which resisted celecoxib-induced radiosensitization. Celecoxib inhibited radiation-induced DNA-PK activation in A549, HSF7, and HCT116 cells, but not in FaDu and HH4dd cells. Consequentially, celecoxib increased residual γH2AX foci after irradiation, demonstrating that inhibition of DNA repair has occurred in responsive A549, HCT116, and HSF7 cells only. Conclusions: Celecoxib enhanced radiosensitivity by inhibition of EGFR-mediated mechanisms of radioresistance, a signaling that was independent of COX-2 activity. This novel observation may have therapeutic implications such that COX-2 inhibitors may improve therapeutic efficacy of radiation even in patients whose tumor radioresistance is not dependent on COX-2

  3. Formation of DNA-protein crosslinks in gamma-irradiated chromatin

    International Nuclear Information System (INIS)

    Mee, L.K.

    1985-01-01

    Gamma-irradiation of chromatin in vitro and in vivo induces DNA-protein crosslinks which are stable to salt and detergent treatment. The efficiency of crosslink formation is 100 times greater in irradiated isolated chromatin than in chromatin irradiated in cells before isolation. Gamma-irradiation of isolated chromatin in the presence of radical scavengers shows that OH . is the most effective radical for the promotion of crosslinking whereas e/sub aq//sup -/ and O/sub 2//sup -/ are essentially ineffective. For chromatin irradiated in the cell before isolation, fewer crosslinks are formed in air than in an atmosphere of nitrogen; the greatest effect is found in cells irradiated in an atmosphere of nitrous oxide, suggesting that OH . may be involved in the formation of crosslinks in vivo. On the basis of comparing radiation-induced crosslinking in whole chromating (DNA, H1 histone, the core histones - H2A, H2B, H3 and H4 - and non-histone chromosomal proteins) and in a chromatin subunit (DNA and the core histones), the authors identified the core histones as the specific chromosomal proteins predominantly involved in crosslinking to DNA

  4. Effect of the uvr D3 mutation on ultraviolet radiation-induced DNA-repair replication in Escherichia coli K12

    International Nuclear Information System (INIS)

    Carlson, K.M.; Smith, K.C.

    1981-01-01

    Ultraviolet-radiation-induced DNA-repair replication was measured in wild-type, polA1, uvrD3, and polA1 uvrD3 strains of Escherichia coli K 12. A large stimulation of repair replication was observed in the uvrD3 strain, compared to the wild-type and polA1 strains. This enhanced repair replication was reduced in the polA1 uvrD3 strain. Therefore, a uvrD3 mutation appears to affect the amount of repair replication performed by DNA polymerase I. In the polA1 strain, there also appears to be an effect of the uvrD3 mutation on the amount of repair replication performed by DNA polymerase III (and/or II). The enhanced repair replication observed for the uvrD3 strains appears to be in response to the enhanced DNA degradation observed for these strains. (orig.)

  5. Identification of DNA Fragments that Showed Linkage to the Radiation-induced Yellow Vein Mosaic Disease Resistance Mutation in Okra

    International Nuclear Information System (INIS)

    Boonsirichai, Kanokporn; Phadvibulya, Valailak; Adthalungrong, Amnuai; Srithongchai, Wanphen; Puripunyavanich, Vichai

    2007-08-01

    Full text: The yellow vein mosaic disease resistant mutant of okra was crossed to Pichit 03, a susceptible variety. Their progeny showed prolonged resistance when compared with Pichit 03. DNA fingerprints of F2 and BC1F1 individuals from the cross indicated that most DNA bands did not segregate with either the resistance or the susceptible characteristics. Nonetheless, polymorphic DNA bands could be identified between the mutant and Okura, the parental variety

  6. Radiation-induced DNA double strand breaks in Ehrlich ascites tumour cells and their possible effects on cell survival

    International Nuclear Information System (INIS)

    Bloecher, D.

    1981-01-01

    A method to prepare high-molecular, pure DNA with the aid of enzymes, detergents, and heat treatment is presented. A sedimentation technique with neutral density gradients has been introduced which permits mass separation and molecular mass analysis of high-molecular DNA (msub(r) 10 ). Using this method, the induction of DNA double strand breaks (DSB) in the dose range between 10 Gy [de

  7. Ionizing radiation-induced DNA damage and its repair in human cells. Final performance report, July 1992--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    Dizdaroglu, M.

    1995-12-31

    The studies of DNA damage in living cells in vitro and in vivo were continued. A variety of systems including cultured mammalian cells, animals, and human tissues were used to conduct these studies. In addition, enzymatic repair of DNA base damage was studied using several DNA glycosylases. To this end, substrate specificities of these enzymes were examined in terms of a large number of base lesions in DNA. In the first phase of the studies, the author sought to introduce improvements to his methodologies for measurement of DNA damage using the technique of gas chromatography/mass spectrometry (GC/MS). In particular, the quantitative measurement of DNA base damage and DNA-protein crosslinks was improved by incorporation of isotope-dilution mass spectrometry into the methodologies. This is one of the most accurate techniques for quantification of organic compounds. Having improved the measurement technique, studies of DNA damage in living cells and DNA repair by repair enzymes were pursued. This report provides a summary of these studies with references to the original work.

  8. DNA repair efficiency in germ cells and early mouse embryos and consequences for radiation-induced transgenerational genomic damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Wyrobek, Andrew J.

    2009-01-18

    Exposure to ionizing radiation and other environmental agents can affect the genomic integrity of germ cells and induce adverse health effects in the progeny. Efficient DNA repair during gametogenesis and the early embryonic cycles after fertilization is critical for preventing transmission of DNA damage to the progeny and relies on maternal factors stored in the egg before fertilization. The ability of the maternal repair machinery to repair DNA damage in both parental genomes in the fertilizing egg is especially crucial for the fertilizing male genome that has not experienced a DNA repair-competent cellular environment for several weeks prior to fertilization. During the DNA repair-deficient period of spermatogenesis, DNA lesions may accumulate in sperm and be carried into the egg where, if not properly repaired, could result in the formation of heritable chromosomal aberrations or mutations and associated birth defects. Studies with female mice deficient in specific DNA repair genes have shown that: (i) cell cycle checkpoints are activated in the fertilized egg by DNA damage carried by the sperm; and (ii) the maternal genotype plays a major role in determining the efficiency of repairing genomic lesions in the fertilizing sperm and directly affect the risk for abnormal reproductive outcomes. There is also growing evidence that implicates DNA damage carried by the fertilizing gamete as a mediator of postfertilization processes that contribute to genomic instability in subsequent generations. Transgenerational genomic instability most likely involves epigenetic mechanisms or error-prone DNA repair processes in the early embryo. Maternal and embryonic DNA repair processes during the early phases of mammalian embryonic development can have far reaching consequences for the genomic integrity and health of subsequent generations.

  9. Radiation-induced cerebrovasculopathy

    International Nuclear Information System (INIS)

    Ikeyama, Yukihide; Abiko, Seisho; Kurokawa, Yasushi; Okamura, Tomomi; Watanabe, Kohsaku; Inoue, Shinichi; Fujii, Yasuhiro.

    1993-01-01

    We reported a patient who suffered from cerebrovasculopathy after irradiation therapy for astrocytoma located at the left temporal lobe. An eleven year-old boy who presented with headache and vomiting received partial removal of a tumor. Histological diagnosis of the tumor was astrocytoma (grade II). His preoperative cerebral angiograms showed mass sign solely, without stenosis or occlusion of the cerebral vessel. Postoperatively, he was treated with irradiation therapy involving the whole brain with a total of 30 Gy, and gamma knife therapy. Six months after irradiation, he started suffering from frequent cerebral ischemic attacks, but there was no regrowth of the tumor visible on CT scans. Cerebral angiograms were made again, and revealed multifocal stenoses in the bilateral internal carotid arteries, middle cerebral arteries, and the anterior cerebral artery. His symptoms did not improve after conservative treatment with steroids, calcium antagonist, or low molecular weight dextran. Although he received a superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses bilaterally, multiple cerebral infarctions appeared. Although irradiation therapy is acceptable in patients with brain tumor, cerebrovasculopathy after irradiation should be considered as one of the most important complications, and the risk incurred by irradiation therapy should lead to more careful consideration and caution when treating intracranial brain tumors, especially in children. From our experience, the usefulness of bypass surgery for radiation-induced cerebrovasculopathy is still controversial. (author)

  10. Exposure to 1800 MHz radiofrequency electromagnetic radiation induces oxidative DNA base damage in a mouse spermatocyte-derived cell line.

    Science.gov (United States)

    Liu, Chuan; Duan, Weixia; Xu, Shangcheng; Chen, Chunhai; He, Mindi; Zhang, Lei; Yu, Zhengping; Zhou, Zhou

    2013-03-27

    Whether exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from mobile phones can induce DNA damage in male germ cells remains unclear. In this study, we conducted a 24h intermittent exposure (5 min on and 10 min off) of a mouse spermatocyte-derived GC-2 cell line to 1800 MHz Global System for Mobile Communication (GSM) signals in GSM-Talk mode at specific absorption rates (SAR) of 1 W/kg, 2 W/kg or 4 W/kg. Subsequently, through the use of formamidopyrimidine DNA glycosylase (FPG) in a modified comet assay, we determined that the extent of DNA migration was significantly increased at a SAR of 4 W/kg. Flow cytometry analysis demonstrated that levels of the DNA adduct 8-oxoguanine (8-oxoG) were also increased at a SAR of 4 W/kg. These increases were concomitant with similar increases in the generation of reactive oxygen species (ROS); these phenomena were mitigated by co-treatment with the antioxidant α-tocopherol. However, no detectable DNA strand breakage was observed by the alkaline comet assay. Taking together, these findings may imply the novel possibility that RF-EMR with insufficient energy for the direct induction of DNA strand breaks may produce genotoxicity through oxidative DNA base damage in male germ cells. Crown Copyright © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis by reactive oxygen species in ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    The aim of this study was to determine whether an increase of ROS level in cellular senescence induced by IR could mediate mtDNA deletion via impairment of mitochondria biogenesis in IMR-90 human lung fibroblast cells. Our results showed that IR induced cellular senescence, intracellular ROS, and mtDNA deletion, and in particular, suppressed the expression of mitochondrial biogenesis genes (NRF-1, TFAM). Furthermore, these IR-induced events were abolished using a potent antioxidant, NAC, which suggests that ROS is a key cause of mtDNA deletion in IR-induced cellular senescence, and that the alteration of mitochondrial biogenesis may mediate these processes

  12. Detection of genetic variability in Basmati and non-Basmati rice varieties and their radiation induced mutants through random amplified polymorphic DNA (RAPD)

    International Nuclear Information System (INIS)

    Farooq, S.; Iqbal, N.; Arif, M.

    1998-01-01

    Random Amplified Polymorphic DNA (RAPDs) markers were utilized to detect polymorphism between pure lines and commercially available Basmati rice varieties to assess variation which may be helpful in quality control and varietal identification (Basmati-370 and derived radiation induced mutants), differentiation of mutants and parents, and identification of RAPD markers co-segregating with important agronomic traits including plant height, days to flower and grain quality. Basmati varieties were distinguished from non-Basmati varieties with the help of five diagnostic markers which will be useful for detecting mixing of non-Basmati and Basmati rices, currently a serious marketing problem. Different Basmati cultivars were identified with the help of diagnostic RAPD markers which can be used in quality control as well as for ''fingerprinting'' of cultivars. Different radiation induced mutants were also successfully distinguished from the parents on the basis of variety specific and mutant specific markers which will be useful for varietal identification. In addition to this, other markers were also identified which can differentiate mutants from each other and are being, used for the fingerprinting of different mutants, particularly the dwarf mutants having similar appearance but different parentage. For identification of RAPD markers co-segregating with plant height and days to flower, 50 F 2 plants and four F 3 families were studied from a reciprocal cross made between Kashmir Basmati (tall and early) and Basmati-198 (dwarf and late). Segregating bands were observed within these populations, and indicating the possible use of RAPD markers for tagging gene(s) of agronomic importance in rice. (author)

  13. Protecting effect on gamma-ray damage of DNA by tea catechin

    International Nuclear Information System (INIS)

    Yoshioka, H.; Akai, G.; Yoshinaga, K.; Hasegawa, K.; Yoshioka, H.

    1995-01-01

    The protecting effect of the tea catechin on the radiation induced scission of DNA in vitro. was examined. In addition, ESR spin-trapping method was used to make clear the mechanism of the protection. (author)

  14. Variation in normal and tumor tissue sensitivity of mice to ionizing radiation-induced DNA strand breaks in vivo

    International Nuclear Information System (INIS)

    Meyn, R.E.; Jenkins, W.T.

    1983-01-01

    The efficiency of DNA strand break formation in normal and tumor tissues of mice was measured using the technique of alkaline elution coupled with a microfluorometric determination of DNA. This methodology allowed measurement of the DNA strand breaks produced in tissues irradiated in vivo with doses of radiation comparable to those used in radiotherapy (i.e., 1.0 gray) without the necessity for the cells to be dividing and incorporating radioactive precursors to label the DNA. The results showed that substantial differences existed among various tissues in terms of the amount of DNA strand break damage produced for a given dose of radiation. Of the normal tissues, the most breaks were produced in bone marrow and the least were produced in gut. Furthermore, strand break production was relatively inefficient in the tumor compared to the normal tissues. The efficiency of DNA strand break formation measured in the cells from the tissues irradiated in vitro was much more uniform and considerably greater than that measured in vivo, suggesting that the normal tissues in the animal may be radiobiologically hypoxic

  15. Inherited Sterility of Fl Male Sitotroga cerealella (Olivier) and changes in the DNA Pattern as a Result of Using Gamma irradiation

    International Nuclear Information System (INIS)

    Rizk, S.A.; Mikhaiel, A.A.

    2009-01-01

    Full grown pupae of the Angoumois grain moth, Sitotroga cerealella were irradiated with 75 and 175 Gy or gamma irradiation .The sterility percent was increased by increasing of' gamma irradiation dose. Also, the sterility percent increased in F 1 males than in parents. Gamma irradiation caused a decrease in size or the ova doles and number of oocytes. The effects of gamma rays on the DNA patterns of adult male parents and Fl males showed alterations among the controls, the treated parents and Ft individuals. Exposure to radiation caused very frequently the appearance of some extra bands and the deficiency of others in the RAPD-PCR amplification patterns of the irradiated insects. However, the similarity in DNA patterns between some normal and treated samples was interpreted by assuming, that the radiation induced damage was in regions of' the genome other than at the loci under study

  16. Production of gamma induced reactive oxygen species and damage of DNA molecule in HaCaT cells under euoxic and hypoxic condition

    International Nuclear Information System (INIS)

    Joseph, P.; Bhat, N.N.; Copplestone, D.; Narayana, Y.

    2014-01-01

    The paper deals with the study of gamma radiation induced reactive oxygen species (ROS) generation in normal human keratinocytes (HaCaT) cells and quantification of subsequent damages induced on DNA molecules. The DNA damages induced in cells after gamma irradiation has been analyzed using Alkaline comet assay. The ROS produced in the cells were quantified by measuring fluorescence after loading the cells with 2', 7' dichlorofluorescin diacetate, a dye that is oxidized into a highly fluorescent form in the presence of peroxides. Studies reveal that in HaCaT cells radical generation occurs when exposed to ionizing radiation and it increases with dose. The induced DNA damages also increases with dose and ROS generation. The study clearly shows the importance of ROS in DNA damage induction and the cells possessing elevated levels of DNA damage after radiation exposure is due to the effect of increased levels of intracellular ROS. (author)

  17. Protective Effect of Curcumin on γ - radiation Induced Chromosome Aberrations in Human Blood Lymphocytes

    International Nuclear Information System (INIS)

    AlSuhaibani, E.S

    2008-01-01

    The present work is aimed at evaluating the radioprotective effect of curcumin on γ radiation induced genetic toxicity. The DNA damage was analyzed by the frequencies of chromosome aberrations assay. Human lymphocytes were treated in vitro with 5.0 γg/ml of curcumin for 30 min at 37 degree C then exposed to 1, 2 and 4 Gy gamma-radiation. The lymphocytes which were pre-treated with curcumin exhibited a significant decrease in the frequency of chromosome aberration at 1 and 2 Gy radiation-induced chromosome damage as compared with the irradiated cells which did not receive the curcumin pretreatment. Thus, pretreatment with curcumin gives protection to lymphocytes against γ-radiation induced chromosome aberration at certain doses. (author)

  18. Radiation Induced Bystander Effect in vivo

    OpenAIRE

    Chai, Yunfei; Hei K. Tom

    2009-01-01

    Radiation-induced bystander effect is defined as the induction of biological effects in cells that are not directly traversed by radiation, but merely in the presence of cells that are. Although radiation induced bystander effects have been well defined in a variety of in vitro models using a range of endpoints including clonogenic survival, mutations, neoplastic transformation, apoptosis, micronucleus, chromosomal aberrations and DNA double strand breaks, the mechanism(s) as well as the pres...

  19. Modulation of DNA methylation levels sensitizes doxorubicin-resistant breast adenocarcinoma cells to radiation-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Luzhna, Lidia [Department of Biological Sciences, University of Lethbridge, AB, Canada T1K 3M4 (Canada); Kovalchuk, Olga, E-mail: olga.kovalchuk@uleth.ca [Department of Biological Sciences, University of Lethbridge, AB, Canada T1K 3M4 (Canada)

    2010-02-05

    Chemoresistant tumors often fail to respond to other cytotoxic treatments such as radiation therapy. The mechanisms of chemo- and radiotherapy cross resistance are not fully understood and are believed to be epigenetic in nature. We hypothesize that MCF-7 cells and their doxorubicin-resistant variant MCF-7/DOX cells may exhibit different responses to ionizing radiation due to their dissimilar epigenetic status. Similar to previous studies, we found that MCF-7/DOX cells harbor much lower levels of global DNA methylation than MCF-7 cells. Furthermore, we found that MCF-7/DOX cells had lower background apoptosis levels and were less responsive to radiation than MCF-7 cells. Decreased radiation responsiveness correlated to significant global DNA hypomethylation in MCF-7/DOX cells. Here, for the first time, we show that the radiation resistance of MCF-7/DOX cells can be reversed by an epigenetic treatment - the application of methyl-donor SAM. SAM-mediated reversal of DNA methylation led to elevated radiation sensitivity in MCF-7/DOX cells. Contrarily, application of SAM on the radiation sensitive and higher methylated MCF-7 cells resulted in a decrease in their radiation responsiveness. This data suggests that a fine balance of DNA methylation is needed to insure proper radiation and drug responsiveness.

  20. In situ action spectra suggest that DNA damage is involved in ultraviolet radiation-induced immunosuppression in humans

    Energy Technology Data Exchange (ETDEWEB)

    Hurks, H.M.H.; Out-Luiting, C.; Vermeer, B.-J.; Claas, F.H.J.; Mommaas, A.M. [University Hospital, Leiden (Netherlands)

    1997-07-01

    The mixed epidermal cell lymphocyte reaction (MECLR) is a commonly used method to study the immunomodulatory effects of UV radiation. The in vitro action spectrum for the MECLR showed that the UV-induced suppression of the MECLR responses is associated with UV-induced DNA damage. To investigate whether in vivo DNA damage also leads to the abrogation of the MECLR, in situ action spectra were made for the MECLR and the induction of thymine dimers (T<>T). Human skin, obtained from plastic surgery, was exposed to monochromatic light of 254, 297, 302 and 312nm. After irradiation, epidermal cells were isolated and used as stimulator cells in the MECLR or processed for flow cytometric detection of T<>T. On the basis of dose-response curves for each wavelength, the action spectyra for suppression of the MECLR and the induction of T<>T were calculated. These spectra showed close similarities, suggesting that, also in situ, UV-induced DNA damage is involved in the UV-induced suppression of the MECLR. Both action spectra showed a small decline from 254 nm to 302 nm, followed by a steep decline to 312 nm. These data show that, in situ, UVC can efficiently induce DNA damage and modulate cutaneous immune responses. (author).

  1. Radiation-induced cross-link DNA damages: synthesis, measurement and insertion into oligonucleotides for replication and enzymatic repair studies

    International Nuclear Information System (INIS)

    Bellon, Sophie

    2003-01-01

    This research thesis addresses the synthesis, measurement and study of the biological impact of radio-induced DNA double damages. In the first part, the author reports the study of the reactivity and fate of the 5-(2'-desoxy-uridilyl)methyl radical which is one of the intermediates formed by oxidizing photo-sensitisation of thymine. The next part reports results of the formation and measurement of double damages of isolated and cellular DNA, notably in the case of γ irradiation. The third part reports the study of in vitro replication of one of the double damages. The behaviour of different polymerases with respect to the damage is reported. Finally, the modified oligonucleotide has been used as a substrate to highlight possible activities of enzymatic repair for this type of cross-link damages by purified proteins or proteins present within cellular extracts [fr

  2. Heavy-ion radiation induces both activation of multiple endogenous transposable elements and alterations in DNA methylation in rice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Li, Xishan; Xiaolin, Cui; Li, Xiang

    2012-07-01

    Space radiation represents a complex environmental condition in which several interacting factors such as electron, neutron, proton, heavy-ion are involved, which may provoke stress responses and jeopardize genome integrity. Given the inherent property of epigenetic modifications to respond to intrinsic aswell as external perturbations, it is conceivable that epigenetic markers like DNA methylation and transposition may undergo alterations in response to space radiation. Cytosine DNA methylation plays important roles in maintaining genome stability and controlling gene expression. A predominant means for Transposable elements (TEs) to cause genetic instability is via their transpositional activation. To find the detailed molecular characterization of the nature of genomic changes induced by space radiation, the seeds of rice were exposed to 0.02, 0.2, 1, 2 and 20 Gy dose of ^{12}C heavy-ion radiation, respectively. We found that extensive alteration in both DNA methylation and gene expression occurred in rice plants after different dose of heavy-ion radiation. Here we shown that heavy-ion radiation has induced transposition of mPing and Tos17 in rice, which belong to distinct classes including the miniature inverted terminal repeat TEs (MITEs) and long-terminal repeat (LTR) retrotransposons, respectively. mPing and Tos17 mobility were found to correlate with cytosine methylation alteration detected by MSAP and genetic variation detected by AFLP. The result showed that at least in some cases transposition of TEs was associated with cytosine demethylation within the elements. Our results implicate that the heavy-ion radiation represents a potent mutagenic agent that can cause genomic instabilities by eliciting transposition of endogenous TEs in rice. Keywords: Heavy-ion radiation, DNA methylation, Transposable elements, mPing, Tos17

  3. The principal phenolic and alcoholic components of wine protect human lymphocytes against hydrogen peroxide- and ionising radiation-induced DNA damage in vitro

    International Nuclear Information System (INIS)

    Fenech, M.; Greenrod, W.

    2003-01-01

    We have tested the hypothesis that the alcoholic and phenolic components of wine are protective against the DNA damaging and cytotoxic effects of hydrogen peroxide and gamma radiation in vitro. The components of wine tested were ethanol, glycerol, a mixture of the phenolic compounds catechin and caffeic acid, and tartaric acid, all at concentrations that were 2.5% or 10.0% of the concentration in a typical Australian white wine Riesling. These components were tested individually or combined as a mixture and compared to a white wine stripped of polyphenols as well as a Hanks balanced salt solution control which was the diluent for the wine components. The effect of the components was tested in lymphocytes, using the cytokinesis-block micronucleus assay, after 30 minutes incubation in plasma or whole blood for the hydrogen peroxide or gamma-radiation challenge respectively. The results obtained showed that ethanol, glycerol, the catechin-caffeic acid mixture, the mixture of all components, and the stripped white wine significantly reduced the DNA damaging effects of hydrogen peroxide and gamma radiation (ANOVA P = 0.043 - 0.001). The strongest protective effect against DNA damage by gamma irradiation was observed for the catechin-caffeic acid mixture and mixture of all components (30% and 32% reduction respectively). These two treatments as well as ethanol produced the strongest protective effects against DNA damage by hydrogen peroxide (24%, 25% and 18% respectively) . The protection provided by the mixture did not account for the expected additive protective effects of the individual components suggesting that the components may be exerting their effects through similar mechanisms which are saturated at the concentrations tested. Ethanol was the only component that significantly increased base-line DNA damage rate, however, this effect was negated in the mixture. In conclusion our results suggest that the main phenolic and alcoholic components of wine can reduce

  4. Silver nanoparticles protect human keratinocytes against UVB radiation-induced DNA damage and apoptosis: potential for prevention of skin carcinogenesis

    Science.gov (United States)

    Arora, Sumit; Tyagi, Nikhil; Bhardwaj, Arun; Rusu, Lilia; Palanki, Rohan; Vig, Komal; Singh, Shree R.; Singh, Ajay P.; Palanki, Srinivas; Miller, Michael E.; Carter, James E.; Singh, Seema

    2015-01-01

    Ultraviolet (UV)-B radiation from the sun is an established etiological cause of skin cancer, which afflicts more than a million lives each year in the United States alone. Here, we tested the chemopreventive efficacy of silver-nanoparticles (AgNPs) against UVB-irradiation-induced DNA damage and apoptosis in human immortalized keratinocytes (HaCaT). AgNPs were synthesized by reduction-chemistry and characterized for their physicochemical properties. AgNPs were well tolerated by HaCaT cells and their pretreatment protected them from UVB-irradiation-induced apoptosis along with significant reduction in cyclobutane-pyrimidine-dimer formation. Moreover, AgNPs pre-treatment led to G1-phase cell-cycle arrest in UVB-irradiated HaCaT cells. AgNPs were efficiently internalized in UVB-irradiated cells and localized into cytoplasmic and nuclear compartments. Furthermore, we observed an altered expression of various genes involved in cell-cycle, apoptosis and nucleotide-excision repair in HaCaT cells treated with AgNPs prior to UVB-irradiation. Together, these findings provide support for potential utility of AgNPs as novel chemopreventive agents against UVB-irradiation-induced skin carcinogenesis. PMID:25804413

  5. Radiation induced nano structures

    International Nuclear Information System (INIS)

    Ibragimova, E.M.; Kalanov, M.U.; Khakimov, Z.

    2006-01-01

    Full text: Nanometer-size silicon clusters have been attracting much attention due to their technological importance, in particular, as promising building blocks for nano electronic and nano photonic systems. Particularly, silicon wires are of great of interest since they have potential for use in one-dimensional quantum wire high-speed field effect transistors and light-emitting devices with extremely low power consumption. Carbon and metal nano structures are studied very intensely due to wide possible applications. Radiation material sciences have been dealing with sub-micron objects for a long time. Under interaction of high energy particles and ionizing radiation with solids by elastic and inelastic mechanisms, at first point defects are created, then they form clusters, column defects, disordered regions (amorphous colloids) and finally precipitates of another crystal phase in the matrix. Such irradiation induced evolution of structure defects and phase transformations was observed by X-diffraction techniques in dielectric crystals of quartz and corundum, which exist in and crystal modifications. If there is no polymorphism, like in alkali halide crystals, then due to radiolysis halogen atoms are evaporated from the surface that results in non-stoichiometry or accumulated in the pores formed by metal vacancies in the sub-surface layer. Nano-pores are created by intensive high energy particles irradiation at first chaotically and then they are ordered and in part filled by inert gas. It is well-known mechanism of radiation induced swelling and embrittlement of metals and alloys, which is undesirable for construction materials for nuclear reactors. Possible solution of this problem may come from nano-structured materials, where there is neither swelling nor embrittlement at gas absorption due to very low density of the structure, while strength keeps high. This review considers experimental observations of radiation induced nano-inclusions in insulating

  6. The Impact of the Geometrical Structure of the DNA on Parameters of the Track-Event Theory for Radiation Induced Cell Kill.

    Directory of Open Access Journals (Sweden)

    Uwe Schneider

    Full Text Available When fractionation schemes for hypofractionation and stereotactic body radiotherapy are considered, a reliable cell survival model at high dose is needed for calculating doses of similar biological effectiveness. An alternative to the LQ-model is the track-event theory which is based on the probabilities for one- and two two-track events. A one-track-event (OTE is always represented by at least two simultaneous double strand breaks. A two-track-event (TTE results in one double strand break. Therefore at least two two-track-events on the same or different chromosomes are necessary to produce an event which leads to cell sterilization. It is obvious that the probabilities of OTEs and TTEs must somehow depend on the geometrical structure of the chromatin. In terms of the track-event theory the ratio ε of the probabilities of OTEs and TTEs includes the geometrical dependence and is obtained in this work by simple Monte Carlo simulations.For this work it was assumed that the anchors of loop forming chromatin are most sensitive to radiation induced cell deaths. Therefore two adjacent tetranucleosomes representing the loop anchors were digitized. The probability ratio ε of OTEs and TTEs was factorized into a radiation quality dependent part and a geometrical part: ε = εion ∙ εgeo. εgeo was obtained for two situations, by applying Monte Carlo simulation for DNA on the tetranucleosomes itself and for linker DNA. Low energy electrons were represented by randomly distributed ionizations and high energy electrons by ionizations which were simulated on rays. εion was determined for electrons by using results from nanodosimetric measurements. The calculated ε was compared to the ε obtained from fits of the track event model to 42 sets of experimental human cell survival data.When the two tetranucleosomes are in direct contact and the hits are randomly distributed εgeo and ε are 0.12 and 0.85, respectively. When the hits are simulated on rays

  7. Down-regulation of NF-κB DNA binding activity by Angelica Sinensis to ameliorate radiation-induced pulmonary injury in mouse model

    International Nuclear Information System (INIS)

    Cao Zhen; Xie Conghua; Zhou Fuxiang; Luo Zhiguo; Zhou Yunfeng; Hang Guang

    2008-01-01

    Objective: To study the trend of NF-kB binding activity during the course of radiation-induced pulmonary injury (RPI), and to evaluate the intervention effect of Angelica Sinensis on it. Methods: Adult female C57BL/6J mice were randomly divided into 4 groups: blank control group (N group), Angelica Sinensis control group (A group), irradiation group (NX group) and irradiation group with Angelica Sinensis intervention (AX group). All mice from the NX and AX groups underwent single fraction of 12 Gy γ-ray delivered to the whole thorax. All mice were intraperitoneally injected 25% Angelica Sinensis injection (20 ml/kg) or identical volume Normal Sodiumdaily injection initiated 1 week before irradiation, lasted till 2 weeks after irradiation. Mice were sacrificed at designated time points (1, 24, 72 h, 1, 2, 4, 8, 16 and 24 weeks), and the whole lungs were removed freshly. HE and Masson staining were performed to provide histopathologic evidence and to evaluate the collagen deposit situation respectively. The immunohistochemical staining of NF-κB P65 protein was performed to identify the location as well as the relative content of P65 protein. The DNA binding activity of NF-κB was detected by TransAM TM ELISA assay. Results: HE and Masson staining manifested that visible pathological alterations began at 2 weeks, typical interstitial pneumonitis were showed at 4 and 8 weeks, collagen deposition was visible from 16 weeks. The NF-κB binding activity detection and the immunohistochemical half-quantity analysis showed two-phase elevation, at 24 h and 8 weeks. Preventive application of Angelica Sinensis revealed prominently ameliorative effect for RPI, with pathological improvement, decreased immunohistochemical staining and lower NF-κB binding activity in both peaks. Conclusions: During the development process of RPI, NF-κB binding activity shows two-phase elevation. Chinese medicine Angelica Sinensis can down-regulate the elevation, showing noted ameliorative effect

  8. Late effects of irradiation of newborn mice with gamma rays. Pt. 4. Summary of investigation and the effect of sex and dose of radiation on the extent of radiation-induced injury

    International Nuclear Information System (INIS)

    Gajewski, A.K.; Slowikowska, M.G.; Chomiczewski, K.; Szram, S.

    1975-01-01

    The results of many years of investigations on late effects of gamma radiation acting on newborn mice are presented. The investigations were carried out on 800 inbred mice strain A irradiated with doses from 150 to 450 R. Irradiation of newborn mice caused permanent damage to the growth mechanisms evidenced by slowing down of weight-gain rate during 220 days of life and decreased weight of internal organs. Besides that, the mortality of irradiated animals increased, similarly as the number of animals with lens changes and the number of chromosome aberrations in bone marrow. Changes were observed also in peripheral blood and significant pathomorphological changes were disclosed in endocrine glands and kidneys. The authors describe also the effect of sex and radiation dose on the extent of radiation-induced injury. Sex effect was observed in 4 cases only out of 34 studied features. The extent of radiation injury increased with increasing dose but in only 12 cases a linear character of increasing injury was observed. In 10 out of these cases the rise in radiation-induced injury per 1 R was in the range 0.001-0.005 and in 2 it exceeded 0.01. (author)

  9. The Analysis of the Patterns of Radiation-Induced DNA Damage Foci by a Stochastic Monte Carlo Model of DNA Double Strand Breaks Induction by Heavy Ions and Image Segmentation Software

    Science.gov (United States)

    Ponomarev, Artem; Cucinotta, F.

    2011-01-01

    To create a generalized mechanistic model of DNA damage in human cells that will generate analytical and image data corresponding to experimentally observed DNA damage foci and will help to improve the experimental foci yields by simulating spatial foci patterns and resolving problems with quantitative image analysis. Material and Methods: The analysis of patterns of RIFs (radiation-induced foci) produced by low- and high-LET (linear energy transfer) radiation was conducted by using a Monte Carlo model that combines the heavy ion track structure with characteristics of the human genome on the level of chromosomes. The foci patterns were also simulated in the maximum projection plane for flat nuclei. Some data analysis was done with the help of image segmentation software that identifies individual classes of RIFs and colocolized RIFs, which is of importance to some experimental assays that assign DNA damage a dual phosphorescent signal. Results: The model predicts the spatial and genomic distributions of DNA DSBs (double strand breaks) and associated RIFs in a human cell nucleus for a particular dose of either low- or high-LET radiation. We used the model to do analyses for different irradiation scenarios. In the beam-parallel-to-the-disk-of-a-flattened-nucleus scenario we found that the foci appeared to be merged due to their high density, while, in the perpendicular-beam scenario, the foci appeared as one bright spot per hit. The statistics and spatial distribution of regions of densely arranged foci, termed DNA foci chains, were predicted numerically using this model. Another analysis was done to evaluate the number of ion hits per nucleus, which were visible from streaks of closely located foci. In another analysis, our image segmentaiton software determined foci yields directly from images with single-class or colocolized foci. Conclusions: We showed that DSB clustering needs to be taken into account to determine the true DNA damage foci yield, which helps to

  10. Role of vitamin A in modulating the radiation-induced changes in intestinal disccharidases of rats exposed to multifractional gamma-radiations

    Energy Technology Data Exchange (ETDEWEB)

    Shaheen, A.A. (Dept. of Biochemistry, Faculty of Pharmacy, Cairo Univ. (Egypt)); Hassan, S.H.M. (Dept. of Drug Radiation Research, National Center of Radiation Research and Technology, Cairo (Egypt))

    1994-08-01

    Rats were subjected to fractionated whole-body irradiation (20x0.5 Gy). Intestinal lactase activity as well as maltase and sucrase activities were assessed. Vitamin A was administered at daily intraperitoneal dose of 15 000 IU/kg body weight for 7 days prior to radiotherapy and thereafter twice weekly throughout therapy up to 7 days post irradiation. In irradiated rats a marked decrease in intestinal lactase activity of about one-fourth of those in nonirradiated rats was observed. In addition, a significant reduction in maltase and sucrase activities of one half of the control group was observed. The application of vitamin A significantly improved the radiation-induced inhibition of intestinal enzymes. Pretreatment application of vitamin A is more efficient to protect against radiation injury than a posttreatment application. (orig./MG)

  11. Measurement of oxidative damage at pyrimidine bases in gamma-irradiated DNA.

    Science.gov (United States)

    Douki, T; Delatour, T; Paganon, F; Cadet, J

    1996-01-01

    Oxidized nucleobases represent one of the main classes of damage induced in DNA by ionizing radiation. Emphasis was placed in this work on the measurement of four oxidized pyrimidine bases, including 5-(hydroxymethyl)uracil (5-HMUra), 5-formyluracil (5-ForUra), 5-hydroxycytosine (5-OHCyt), and 5-hydroxyuracil (5-OHUra), in isolated DNA upon exposure to gamma radiation in aerated aqueous solution. For this purpose, both high performance liquid chromatography associated with electrochemical detection (HPLC-EC) and gas chromatography coupled to mass spectrometry (GC-MS) were used. Conditions of hydrolysis of the N-glycosidic bond were carefully checked in order to achieve a quantitative release of the lesions. We showed that 60% formic acid treatment leads to the decomposition of the four lesions studied. On the other hand, hydrolysis based on the use of either 88% formic acid or 70% hydrogen fluoride in pyridine (HF/Pyr) allowed the quantitative release of the modified bases, with the exception of 5-HMUra when the latter reagent was utilized. A dose course study of the radiation-induced formation of 5-HMUra and 5-ForUra in DNA by using the GC-MS assay showed that the latter lesion was produced in a 2.1-fold higher yield than the former one. HF/Pyr and 88% formic acid hydrolysis provided similar results for 5-ForUra, indicating the reliability of both techniques for the measurement of this lesion. For 5-OHUra and 5-OHCyt, the level of modification determined by GC-MS analysis was higher after 88% formic acid treatment than upon HF/Pyr hydrolysis. When DNA was enzymatically digested and analyzed by HPLC-EC for 5-OHdCyd and 5-OHdUrd, the results were very close to those obtained by GC-MS following HF/Pyr treatment. It was concluded that additional amounts of both 5-OHUra and 5-OHCyt are produced during the 88% formic acid treatment from radiation-induced 5,6-saturated pyrimidine precursors. It is likely that cytosine and uracil diols are involved in this reaction. The

  12. Continuous induction of unscheduled DNA synthesis by gamma irradiation

    International Nuclear Information System (INIS)

    Weniger, P.; Klein, W.; Ott, E.; Kocsis, F.; Altmann, H.

    1988-08-01

    The induction of DNA-synthesis in non-S-phase cells is a very sensitive measure of a preceding damage of the DNA. Usually, in an in vivo -in vitro test (treatment of an animal, incorporation of H3-thymidine in a cell suspension) the damaging of DNA takes place hours to days before the evaluation. In this case, the time course of the UDS-induction after a single dose of 1 Gy gamma irradiation should be observed for a long time (21 months). C57 black mice served as test animals. In an age of about 80 days they were irradiated and the induction of unscheduled DNA synthesis was measured at ten points of time during the whole life-span of the animals. Although the repair in this gamma radiation damage in DNA is a very quick process - with centrifugation in alkaline sucrose you find a half time of some minutes - an induction of unscheduled DNA synthesis could be seen at the irradiated animals until the end of their life (640 days). The reason for this could be permanent disorders in cellular regulation caused by the gamma irradiation. 4 figs. (Author)

  13. Prophylactic Properties Of Licorice Roots (GLYCYRRHIZA Gabbler) And / Or Aspirin (Acetylsalicylic Acid) Against GAMMA Radiation-Induced Oxidative Stress And Metabolic Disorders In Rats

    International Nuclear Information System (INIS)

    FAHIM, TH.M.; ABDEL FATTAH, S.M.

    2009-01-01

    Oxidative stress with subsequent production of reactive oxygen species (ROS) has been postulated as one of the mechanism of cardiac and renal toxicity. The aim of the present study is to investigate the possible protective effects of licorice and/or aspirin on gamma irradiation-induced cardiac and renal damage in rats. Licorice and/or aspirin was supplemented daily to rats (100 mg licorice/kg body wt and 50 mg aspirin/kg body wt) orally, 15 days before and after whole body gamma irradiation at a dose of 6 Gy (applied as a shot dose). Gamma irradiation caused significant drop in haemoglobin, erythrocytes, haematocrit values, platelets count, prothrombin time (PT) and leukocytes with their differential counts with elevation in C-reactive protein (CRP) and activated partial thromboplastin time (aPTT).The results obtained showed that whole body gamma irradiation of rats induced biochemical alteration in the levels of serum lipid profile (total lipids, total cholesterol, triglycerides, high density lipoprotein-cholesterol and low density lipoprotein-cholesterol), creatinine and urea. Furthermore, some markers of cardiac injury enzymes such as serum aspartate transaminase (AST), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) activities showed significant increase associated with decrease in the glutathione content (GSH) of cardiac and renal tissues. Significant increase of lipid peroxidation end products malondialdehyde (MDA) and nitric oxide (NO) in the cardiac and renal tissues was observed.Licorice and/or aspirin treatment prior and post gamma irradiation of rats has attenuated the renal and cardiac toxic effects of radiation manifested by reduction in the levels of MDA and NO, rescued the depletion of endogenous GSH, haematologial parameters and diminished the increase of cardiac and renal injury markers .

  14. Determination of radiation-induced DNA double-strand breaks for the biological dose monitoring in cardiac computerized tomography; Bestimmung von strahleninduzierten DNA-Doppelstrangbruechen zum Monitoring der biologischen Dosis in der Herz-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Wegener, Jasmin

    2013-11-12

    Background and aims: X-rays cause relevant DNA damage to cells. DNA double-strand breaks (DSBs) are considered to be the most biologically significant radiation induced DNA-lesions. Recently a sensitive immunofluorescence microscopic method was developed to quantify x-ray induced DSBs as nuclear foci, even after doses as used in computed tomography. The method is based on the phosphorylation of the histone variant H2AX after formation of DSBs and distinct foci representing DSBs can be visualised. The number of foci correlates well with the delivered radiation dose. The importance of cardiac CT has increased during the last years. The radiation exposure of cardiac CT is rather high compared to other radiologic diagnostic procedures and techniques for dose-reduction receive increasing attention. In this context the purpose of this study was to determine to what extent the γ-H2AX-based method is able to measure x-ray induced DSBs in patients undergoing cardiac CT. Furthermore the objective was to evaluate whether CT-induced DSBs correlate with exposure parameters (dose length product, DLP) and to assess the influence of the scan protocols on the biological radiation damage. Materials and methods: 32 patients undergoing coronary CT angiography either using a 64-slice (n = 5: SOMATOM Sensation 64 {sup registered}) or a dual-source CT scanner (n = 27: SOMATOM Definition {sup registered}) were included in the study. Venous blood samples were taken before and 0.5 h, 2.5 h, and 24 h after the CT scan. Additional venous blood samples obtained before CT were irradiated in-vitro at various radiation doses (10 mGy, 50 mGy, 100 mGy) to obtain reference values of foci. Lymphocytes were separated and incubated with a specific γ-H2AX primary and a fluorescent secondary antibody. The number of γ-H2AX-foci was quantified using a fluorescence microscope. Every distinct focus represents one DNA-DSB. The number of radiation-induced DSBs was calculated by subtracting the foci number

  15. UV-B radiation induces epithelial tumors in mice lacking DNA polymerase eta and mesenchymal tumors in mice deficient for DNA polymerase iota.

    Science.gov (United States)

    Ohkumo, Tsuyoshi; Kondo, Yuji; Yokoi, Masayuki; Tsukamoto, Tetsuya; Yamada, Ayumi; Sugimoto, Taiki; Kanao, Rie; Higashi, Yujiro; Kondoh, Hisato; Tatematsu, Masae; Masutani, Chikahide; Hanaoka, Fumio

    2006-10-01

    DNA polymerase eta (Pol eta) is the product of the Polh gene, which is responsible for the group variant of xeroderma pigmentosum, a rare inherited recessive disease which is characterized by susceptibility to sunlight-induced skin cancer. We recently reported in a study of Polh mutant mice that Pol eta is involved in the somatic hypermutation of immunoglobulin genes, but the cancer predisposition of Polh-/- mice has not been examined until very recently. Another translesion synthesis polymerase, Pol iota, a Pol eta paralog encoded by the Poli gene, is naturally deficient in the 129 mouse strain, and the function of Pol iota is enigmatic. Here, we generated Polh Poli double-deficient mice and compared the tumor susceptibility of them with Polh- or Poli-deficient animals under the same genetic background. While Pol iota deficiency does not influence the UV sensitivity of mouse fibroblasts irrespective of Polh genotype, Polh Poli double-deficient mice show slightly earlier onset of skin tumor formation. Intriguingly, histological diagnosis after chronic treatment with UV light reveals that Pol iota deficiency leads to the formation of mesenchymal tumors, such as sarcomas, that are not observed in Polh(-/-) mice. These results suggest the involvement of the Pol eta and Pol iota proteins in UV-induced skin carcinogenesis.

  16. UV-B Radiation Induces Epithelial Tumors in Mice Lacking DNA Polymerase η and Mesenchymal Tumors in Mice Deficient for DNA Polymerase ι

    Science.gov (United States)

    Ohkumo, Tsuyoshi; Kondo, Yuji; Yokoi, Masayuki; Tsukamoto, Tetsuya; Yamada, Ayumi; Sugimoto, Taiki; Kanao, Rie; Higashi, Yujiro; Kondoh, Hisato; Tatematsu, Masae; Masutani, Chikahide; Hanaoka, Fumio

    2006-01-01

    DNA polymerase η (Pol η) is the product of the Polh gene, which is responsible for the group variant of xeroderma pigmentosum, a rare inherited recessive disease which is characterized by susceptibility to sunlight-induced skin cancer. We recently reported in a study of Polh mutant mice that Pol η is involved in the somatic hypermutation of immunoglobulin genes, but the cancer predisposition of Polh−/− mice has not been examined until very recently. Another translesion synthesis polymerase, Pol ι, a Pol η paralog encoded by the Poli gene, is naturally deficient in the 129 mouse strain, and the function of Pol ι is enigmatic. Here, we generated Polh Poli double-deficient mice and compared the tumor susceptibility of them with Polh- or Poli-deficient animals under the same genetic background. While Pol ι deficiency does not influence the UV sensitivity of mouse fibroblasts irrespective of Polh genotype, Polh Poli double-deficient mice show slightly earlier onset of skin tumor formation. Intriguingly, histological diagnosis after chronic treatment with UV light reveals that Pol ι deficiency leads to the formation of mesenchymal tumors, such as sarcomas, that are not observed in Polh−/− mice. These results suggest the involvement of the Pol η and Pol ι proteins in UV-induced skin carcinogenesis. PMID:17015482

  17. Radiation induced oral mucositis

    Directory of Open Access Journals (Sweden)

    P S Satheesh Kumar

    2009-01-01

    Full Text Available Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii who also received concomitant chemotherapy; (iii who received a total dose over 5,000 cGy; and (iv who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene

  18. Radiation-induced gene expression in human subcutaneous fibroblasts is predictive of radiation-induced fibrosis

    DEFF Research Database (Denmark)

    Rødningen, Olaug Kristin; Børresen-Dale, Anne-Lise; Alsner, Jan

    2008-01-01

    BACKGROUND AND PURPOSE: Breast cancer patients show a large variation in normal tissue reactions after ionizing radiation (IR) therapy. One of the most common long-term adverse effects of ionizing radiotherapy is radiation-induced fibrosis (RIF), and several attempts have been made over the last...... years to develop predictive assays for RIF. Our aim was to identify basal and radiation-induced transcriptional profiles in fibroblasts from breast cancer patients that might be related to the individual risk of RIF in these patients. MATERIALS AND METHODS: Fibroblast cell lines from 31 individuals......-treated fibroblasts. Transcriptional differences in basal and radiation-induced gene expression profiles were investigated using 15K cDNA microarrays, and results analyzed by both SAM and PAM. RESULTS: Sixty differentially expressed genes were identified by applying SAM on 10 patients with the highest risk of RIF...

  19. Silencing expression of the catalytic subunit of DNA-dependent protein kinase by small interfering RNA sensitizes human cells for radiation-induced chromosome damage, cell killing, and mutation

    Science.gov (United States)

    Peng, Yuanlin; Zhang, Qinming; Nagasawa, Hatsumi; Okayasu, Ryuichi; Liber, Howard L.; Bedford, Joel S.

    2002-01-01

    Targeted gene silencing in mammalian cells by RNA interference (RNAi) using small interfering RNAs (siRNAs) was recently described by Elbashir et al. (S. M. Elbashir et al., Nature (Lond.), 411: 494-498, 2001). We have used this methodology in several human cell strains to reduce expression of the Prkdc (DNA-PKcs) gene coding for the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) that is involved in the nonhomologous end joining of DNA double-strand breaks. We have also demonstrated a radiosensitization for several phenotypic endpoints of radiation damage. In low-passage normal human fibroblasts, siRNA knock-down of DNA-PKcs resulted in a reduced capacity for restitution of radiation-induced interphase chromosome breaks as measured by premature chromosome condensation, an increased yield of acentric chromosome fragments at the first postirradiation mitosis, and an increased radiosensitivity for cell killing. For three strains of related human lymphoblasts, DNA-PKcs-targeted siRNA transfection resulted in little or no increase in radiosensitivity with respect to cell killing, a 1.5-fold decrease in induced mutant yield in TK6- and p53-null NH32 cells, but about a 2-fold increase in induced mutant yield in p53-mutant WTK1 cells at both the hypoxanthine quanine phosphoribosyl transferase (hprt) and the thymidine kinase loci.

  20. Radiation-induced bystander effects in the Atlantic salmon (salmo salar L.) following mixed exposure to copper and aluminum combined with low-dose gamma radiation

    International Nuclear Information System (INIS)

    Mothersill, Carmel; Seymour, Colin B.; Smith, Richard W.; Heier, Lene Soerlie; Teien, Hans-Christian; Land, Ole Christian; Oughton, Deborah; Salbu, Brit

    2014-01-01

    Very little is known about the combined effects of low doses of heavy metals and radiation. However, such ''multiple stressor'' exposure is the reality in the environment. In the work reported in this paper, fish were exposed to cobalt 60 gamma irradiation with or without copper or aluminum in the water. Doses of radiation ranged from 4 to 75 mGy delivered over 48 or 6 h. Copper doses ranged from 10 to 80 μg/L for the same time period. The aluminum dose was 250 μg/L. Gills and skin were removed from the fish after exposure and explanted in tissue culture flasks for investigation of bystander effects of the exposures using a stress signal reporter assay, which has been demonstrated to be a sensitive indicator of homeostatic perturbations in cells. The results show complex synergistic interactions of radiation and copper. Gills on the whole produce more toxic bystander signals than skin, but the additivity scores show highly variable results which depend on dose and time of exposure. The impacts of low doses of copper and low doses of radiation are greater than additive, medium levels of copper alone have a similar level of effect of bystander signal toxicity to the low dose. The addition of radiation stress, however, produces clear protective effects in the reporters treated with skin-derived medium. Gill-derived medium from the same fish did not show protective effects. Radiation exposure in the presence of 80 μg/L led to highly variable results, which due to animal variation were not significantly different from the effect of copper alone. The results are stressor type, stressor concentration and time dependent. Clearly co-exposure to radiation and heavy metals does not always lead to simple additive effects. (orig.)

  1. Radiation-induced bystander effects in the Atlantic salmon (salmo salar L.) following mixed exposure to copper and aluminum combined with low-dose gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mothersill, Carmel; Seymour, Colin B. [McMaster University, Medical Physics and Applied Radiation Sciences Department, Hamilton, ON (Canada); Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, Aas (Norway); Smith, Richard W. [McMaster University, Medical Physics and Applied Radiation Sciences Department, Hamilton, ON (Canada); Heier, Lene Soerlie; Teien, Hans-Christian; Land, Ole Christian; Oughton, Deborah; Salbu, Brit [Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, Aas (Norway)

    2014-03-15

    Very little is known about the combined effects of low doses of heavy metals and radiation. However, such ''multiple stressor'' exposure is the reality in the environment. In the work reported in this paper, fish were exposed to cobalt 60 gamma irradiation with or without copper or aluminum in the water. Doses of radiation ranged from 4 to 75 mGy delivered over 48 or 6 h. Copper doses ranged from 10 to 80 μg/L for the same time period. The aluminum dose was 250 μg/L. Gills and skin were removed from the fish after exposure and explanted in tissue culture flasks for investigation of bystander effects of the exposures using a stress signal reporter assay, which has been demonstrated to be a sensitive indicator of homeostatic perturbations in cells. The results show complex synergistic interactions of radiation and copper. Gills on the whole produce more toxic bystander signals than skin, but the additivity scores show highly variable results which depend on dose and time of exposure. The impacts of low doses of copper and low doses of radiation are greater than additive, medium levels of copper alone have a similar level of effect of bystander signal toxicity to the low dose. The addition of radiation stress, however, produces clear protective effects in the reporters treated with skin-derived medium. Gill-derived medium from the same fish did not show protective effects. Radiation exposure in the presence of 80 μg/L led to highly variable results, which due to animal variation were not significantly different from the effect of copper alone. The results are stressor type, stressor concentration and time dependent. Clearly co-exposure to radiation and heavy metals does not always lead to simple additive effects. (orig.)

  2. Radiation Induced Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F.

    2011-03-01

    Radiation induced genomic instability can be observed in the progeny of irradiated cells multiple generations after irradiation of parental cells. The phenotype is well established both in vivo (Morgan 2003) and in vitro (Morgan 2003), and may be critical in radiation carcinogenesis (Little 2000, Huang et al. 2003). Instability can be induced by both the deposition of energy in irradiated cells as well as by signals transmitted by irradiated (targeted) cells to non-irradiated (non-targeted) cells (Kadhim et al. 1992, Lorimore et al. 1998). Thus both targeted and non-targeted cells can pass on the legacy of radiation to their progeny. However the radiation induced events and cellular processes that respond to both targeted and non-targeted radiation effects that lead to the unstable phenotype remain elusive. The cell system we have used to study radiation induced genomic instability utilizes human hamster GM10115 cells. These cells have a single copy of human chromosome 4 in a background of hamster chromosomes. Instability is evaluated in the clonal progeny of irradiated cells and a clone is considered unstable if it contains three or more metaphase sub-populations involving unique rearrangements of the human chromosome (Marder and Morgan 1993). Many of these unstable clones have been maintained in culture for many years and have been extensively characterized. As initially described by Clutton et al., (Clutton et al. 1996) many of our unstable clones exhibit persistently elevated levels of reactive oxygen species (Limoli et al. 2003), which appear to be due dysfunctional mitochondria (Kim et al. 2006, Kim et al. 2006). Interestingly, but perhaps not surprisingly, our unstable clones do not demonstrate a “mutator phenotype” (Limoli et al. 1997), but they do continue to rearrange their genomes for many years. The limiting factor with this system is the target – the human chromosome. While some clones demonstrate amplification of this chromosome and thus lend

  3. Injection profiles with radiation induced copolymers

    International Nuclear Information System (INIS)

    Knight, B.L.; Rhudy, J.S.; Gogarty, W.B.

    1976-01-01

    The injectivity profile of a heterogeneous formation and/or vertical conformance is improved by injecting an aqueous solution into the formation, the solution containing a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in a 10 to 60 percent aqueous solution with gamma radiation; the aqueous monomer solution preferably contains 25 to 99 percent acrylamide and 1 to 75 percent sodium acrylate. Immiscible, miscible, or miscible-like displacing processes can be used in conjunction with this invention. 20 claims

  4. Radiation induced peroxidative damage: mechanism and significance

    International Nuclear Information System (INIS)

    Agrawal, Anjali; Kale, R.K.

    2001-01-01

    An interest has been generated in free radicals after the discovery of superoxide dismutase. These free radicals cause a number of diseases and are involved in the detrimental effect of ionizing radiation. Efforts have been made to understand their role in damage and death of the cell using lipid peroxidation process. Lipid peroxidation is an important effect of radiation on membranes, which apart from DNA, are critical targets of radiation action. This paper addresses the basic mechanism of radiation induced lipid peroxidation. Various factors, which determine the mode and magnitude of lipid peroxidation, are also discussed. Lipid peroxidation is shown to have importance in understanding the modifications of radiation effects. Efforts are made to show similarities between radiolytic and non-radiolytic lipid peroxidation. Recent findings related to the close link between radiation-induced lipid peroxidation and apoptosis are likely to open new avenues for future research and to develop new approaches for radio modification of biological effects. (author)

  5. Detection, characterization and measure of a new radiation-induced damage in isolated and cellular DNA; Detection, caracterisation et mesure d'un nouveau dommage radio-induit de l'ADN isole et cellulaire

    Energy Technology Data Exchange (ETDEWEB)

    Regulus, P

    2006-10-15

    Deoxyribonucleic acid (DNA) contains the genetic information and chemical injury to this macromolecule may have severe biological consequences. We report here the detection of 4 new radiation-induced DNA lesions by using a high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) approach. For that purpose, the characteristic fragmentation of most 2'-deoxy-ribo nucleosides, the loss of 116 Da corresponding to the loss of the 2-deoxyribose moiety, was used in the so-called neutral loss mode of the HPLC-MS/MS. One of the newly detected lesions, named dCyd341 because it is a 2'-deoxycytidine modification exhibiting a molecular weight of 341 Da, was also detected in cellular DNA. Characterization of this modified nucleoside was performed using NMR and exact mass determination of the product obtained by chemical synthesis. A mechanism of formation was then proposed, in which the first event is the H-abstraction at the C4 position of a 2-deoxyribose moiety. Then, the sugar modification produced exhibits a reactive aldehyde that, through reaction with a vicinal cytosine base, gives rise to dCyd341. dCyd341 could be considered as a complex damage since its formation involves a DNA strand break and a cross-link between a damaged sugar residue and a vicinal cytosine base located most probably on the complementary DNA strand. In addition to its characterization, preliminary biological studies revealed that cells are able to remove the lesion from DNA. Repair studies have revealed the ability of cells to excise the lesion. Identification of the repair systems involved could represent an interesting challenge. (author)

  6. Mechanisms of radiation-induced neoplastic cell transformation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, T.C.H.; Tobias, C.A.

    1984-04-01

    Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table.

  7. Mechanisms of radiation-induced neoplastic cell transformation

    International Nuclear Information System (INIS)

    Yang, T.C.H.; Tobias, C.A.

    1984-04-01

    Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table

  8. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis are mediated by reactive oxygen species in ionizing radiation-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee [Radiation Biotechnology Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Young Sang [College of Natural Sciences, Chungnam National University, Daejeon (Korea, Republic of)

    2011-09-15

    Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging, and contributes to harmful effects in cultured cells and animal tissues. mtDNA biogenesis genes (NRF-1, TFAM) are essential for the maintenance of mtDNA, as well as the transcription and replication of mitochondrial genomes. Considering that oxidative stress is known to affect mitochondrial biogenesis, we hypothesized that ionizing radiation (IR)-induced reactive oxygen species (ROS) causes mtDNA deletion by modulating the mitochondrial biogenesis, thereby leading to cellular senescence. Therefore, we examined the effects of IR on ROS levels, cellular senescence, mitochondrial biogenesis, and mtDNA deletion in IMR-90 human lung fibroblast cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated at 4 or 8 Gy. Old cells at PD55, and H2O2-treated young cells at PD 39, were compared as a positive control. The IR increased the intracellular ROS level, senescence-associated {beta}-galactosidase (SA-{beta}-gal) activity, and mtDNA common deletion (4977 bp), and it decreased the mRNA expression of NRF-1 and TFAM in IMR-90 cells. Similar results were also observed in old cells (PD 55) and H{sub 2}O{sub 2}-treated young cells. To confirm that a increase in ROS level is essential for mtDNA deletion and changes of mitochondrial biogenesis in irradiated cells, the effects of N-acetylcysteine (NAC) were examined. In irradiated and H{sub 2}O{sub 2}-treated cells, 5 mM NAC significantly attenuated the increases of ROS, mtDNA deletion, and SA-{beta}-gal activity, and recovered from decreased expressions of NRF-1 and TFAM mRNA. These results suggest that ROS is a key cause of IR-induced mtDNA deletion, and the suppression of the mitochondrial biogenesis gene may mediate this process.

  9. Mitochondrial DNA deletion and impairment of mitochondrial biogenesis are mediated by reactive oxygen species in ionizing radiation-induced premature senescence

    International Nuclear Information System (INIS)

    Eom, Hyeon Soo; Jung, U Hee; Jo, Sung Kee; Kim, Young Sang

    2011-01-01

    Mitochondrial DNA (mtDNA) deletion is a well-known marker for oxidative stress and aging, and contributes to harmful effects in cultured cells and animal tissues. mtDNA biogenesis genes (NRF-1, TFAM) are essential for the maintenance of mtDNA, as well as the transcription and replication of mitochondrial genomes. Considering that oxidative stress is known to affect mitochondrial biogenesis, we hypothesized that ionizing radiation (IR)-induced reactive oxygen species (ROS) causes mtDNA deletion by modulating the mitochondrial biogenesis, thereby leading to cellular senescence. Therefore, we examined the effects of IR on ROS levels, cellular senescence, mitochondrial biogenesis, and mtDNA deletion in IMR-90 human lung fibroblast cells. Young IMR-90 cells at population doubling (PD) 39 were irradiated at 4 or 8 Gy. Old cells at PD55, and H2O2-treated young cells at PD 39, were compared as a positive control. The IR increased the intracellular ROS level, senescence-associated β-galactosidase (SA-β-gal) activity, and mtDNA common deletion (4977 bp), and it decreased the mRNA expression of NRF-1 and TFAM in IMR-90 cells. Similar results were also observed in old cells (PD 55) and H 2 O 2 -treated young cells. To confirm that a increase in ROS level is essential for mtDNA deletion and changes of mitochondrial biogenesis in irradiated cells, the effects of N-acetylcysteine (NAC) were examined. In irradiated and H 2 O 2 -treated cells, 5 mM NAC significantly attenuated the increases of ROS, mtDNA deletion, and SA-β-gal activity, and recovered from decreased expressions of NRF-1 and TFAM mRNA. These results suggest that ROS is a key cause of IR-induced mtDNA deletion, and the suppression of the mitochondrial biogenesis gene may mediate this process.

  10. Nrf2 facilitates repair of radiation induced DNA damage through homologous recombination repair pathway in a ROS independent manner in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, Sundarraj; Pal, Debojyoti; Sandur, Santosh K., E-mail: sskumar@barc.gov.in

    2015-09-15

    Highlights: • Nrf2 inhibition in A549 cells led to attenuated DNA repair and radiosensitization. • Influence of Nrf2 on DNA repair is not linked to its antioxidant function. • Nrf2 influences DNA repair through homologous recombination (HR) repair pathway. • Many genes involved in HR pathway show ARE sequences in their upstream region. - Abstract: Nrf2 is a redox sensitive transcription factor that is involved in the co-ordinated transcription of genes involved in redox homeostasis. But the role of Nrf2 in DNA repair is not investigated in detail. We have employed A549 and MCF7 cells to study the role of Nrf2 on DNA repair by inhibiting Nrf2 using all-trans retinoic acid (ATRA) or by knock down approach prior to radiation exposure (4 Gy). DNA damage and repair analysis was studied by γH2AX foci formation and comet assay. Results suggested that the inhibition of Nrf2 in A549 or MCF7 cells led to significant slowdown in DNA repair as compared to respective radiation controls. The persistence of residual DNA damage even in the presence of free radical scavenger N-acetyl cysteine, suggested that the influence of Nrf2 on DNA repair was not linked to its antioxidant functions. Further, its influence on non-homologous end joining repair pathway was studied by inhibiting both Nrf2 and DNA-PK together. This led to synergistic reduction of survival fraction, indicating that Nrf2 may not be influencing the NHEJ pathway. To investigate the role of homologous recombination repair (HR) pathway, RAD51 foci formation was monitored. There was a significant reduction in the foci formation in cells treated with ATRA or shRNA against Nrf2 as compared to their respective radiation controls. Further, Nrf2 inhibition led to significant reduction in mRNA levels of RAD51. BLAST analysis was also performed on upstream regions of DNA repair genes to identify antioxidant response element and found that many repair genes that are involved in HR pathway may be regulated by Nrf2

  11. On the effect of oxygen or copper(II) in radiation-induced degradation of DNA in the presence of thiols

    International Nuclear Information System (INIS)

    Pruetz, W.A.; Moenig, Hans

    1987-01-01

    Degradiation of DNA when γ-irradiated in aqueous solutions containing cysteine can be efficiently enhanced not only with oxygen, but to the same extent also with Cu 2+ ions under hypoxic conditions. The result can be explained by 'self-repair' in this sytem due to recombination of DNA radical with RSS radical - R intermediates, and repair inhibition by oxygen or copper involving RSS radical - R scavenging. It is emphasized that oxygen enhancement in DNA-thiol systems may occur not only by peroxidation, via defect fixation (DNA-O radical 2 ) or thiol activation (RS-O radical 2 ), but also by the well-established inactivation of RSS radical - R by oxygen. There is evidence also from literature data for a correlation between oxygen enhancement and RSS radical - R stability, which varies with thiol concentration, pH and thiol structure. (author)

  12. Radiation induced microbial pesticide

    International Nuclear Information System (INIS)

    Kim, Ki Yup; Lee, Young Keun; Kim, Jae Sung; Kim, Jin Kyu; Lee, Sang Jae

    2000-01-01

    To control plant pathogenic fungi, 4 strains of bacteria (K1, K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 13 kinds of fungi. Mutants of K1 and YS1 strains were induced by gamma-ray radiation and showed promising antifungal activities. These wild type and mutants showed resistant against more than 27 kinds of commercial pesticides among 30 kinds of commercial pesticides test particularly, YS1-1006 mutant strain showed resistant against hydrogen oxide. And mutants had increased antifungal activity against Botryoshaeria dothidea. These results suggested that radiation could be an useful method for the induction of functional mutants. (author)

  13. Effects of formic acid hydrolysis on the quantitative analysis of radiation-induced DNA base damage products assayed by gas chromatography/mass spectrometry

    International Nuclear Information System (INIS)

    Swarts, S.G.; Smith, G.S.; Miao, L.; Wheeler, K.T.

    1996-01-01

    Gas chromatography/mass spectrometry (GC/ MS-SIM) is an excellent technique for performing both qualitative and quantitative analysis of DNA base damage products that are formed by exposure to ionizing radiation or by the interaction of intracellular DNA with activated oxygen species. This technique commonly uses a hot formic acid hydrolysis step to degrade the DNA to individual free bases. However, due to the harsh nature of this degradation procedure, the quantitation of DNA base damage products may be adversely affected. Consequently, we examined the effects of various formic acid hydrolysis procedures on the quantitation of a number of DNA base damage products and identified several factors that can influence this quantitation. These factors included (1) the inherent acid stabilities of both the lesions and the internal standards; (2) the hydrolysis temperature; (3) the source and grade of the formic acid; and (4) the sample mass during hydrolysis. Our data also suggested that the N, O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) derivatization efficiency can be adversely affected, presumably by trace contaminants either in the formic acid or from the acid-activated surface of the glass derivatization vials. Where adverse effects were noted, modifications were explored in an attempt to improve the quantitation of these DNA lesions. Although experimental steps could be taken to minimize the influence of these factors on the quantitation of some base damage products, no single procedure solved the quantitation problem for all base lesions. However, a significant improvement in the quantitation was achieved if the relative molecular response factor (RMRF) values for these lesions were generated with authentic DNA base damage products that had been treated exactly like the experimental samples. (orig.)

  14. Low Dose Radiation-Induced Genome and Epigenome Instability Symposium and Epigenetic Mechanisms, DNA Repair, and Chromatin Symposium at the EMS 2008 Annual Meeting - October 2008

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F; Kovalchuk, Olga; Dolinoy, Dana C; Dubrova, Yuri E; Coleman, Matthew A; Schär, Primo; Pogribny, Igor; Hendzel, Michael

    2010-02-19

    The Low Dose Radiation Symposium thoughtfully addressed ionizing radiation non-mutational but transmissable alterations in surviving cells. Deregulation of epigenetic processes has been strongly implicated in carcinogenesis, and there is increasing realization that a significant fraction of non-targeted and adaptive mechanisms in response to ionizing radiation are likely to be epigenetic in nature. Much remains to be learned about how chromatin and epigenetic regulators affect responses to low doses of radiation, and how low dose radiation impacts other epigenetic processes. The Epigenetic Mechanisms Symposium focused on on epigenetic mechanisms and their interplay with DNA repair and chromatin changes. Addressing the fact that the most well understood mediators of epigenetic regulation are histone modifications and DNA methylation. Low levels of radiation can lead to changes in the methylation status of certain gene promoters and the expression of DNA methyltransferases, However, epigenetic regulation can also involve changes in higher order chromosome structure.

  15. Development of techniques using DNA analysis method for detection/analysis of radiation-induced mutation. Development of an useful probe/primer and improvement of detection efficacy

    International Nuclear Information System (INIS)

    Maekawa, Hideaki; Tsuchida, Kozo; Hashido, Kazuo; Takada, Naoko; Kameoka, Yosuke; Hirata, Makoto

    1999-01-01

    Previously, it was demonstrated that detection of centromere became easy and reliable through fluorescent staining by FISH method using a probe of the sequence preserved in α-satelite DNA. Since it was, however, found inappropriate to detect dicentrics based on the relative amount of DNA probe on each chromosome. A prove which allows homogeneous detection of α-satelite DNA for each chromosome was constructed. A presumed sequence specific to kinetochore, CENP-B box was amplified by PCR method and the product DNA was used as a probe. However, the variation in amounts of probe DNA among chromosomes was decreased by only about 20%. Then, a program for image processing of the results obtained from FISH using α-satelite DNA was constructed to use as a marker for centromere. When compared with detection of abnormal chromosomes stained by the conventional method, calculation efficacy for only detection of centromere was improved by the use of this program. Calculation to discriminate the normal or not was still complicated and the detection efficacy was little improved. Chromosomal abnormalities in lymphocytes were used to detect the effects of radiation. In this method, it is needed to shift the phase of cells into metaphase. The mutation induced by radiation might be often repaired during shifting. To exclude this possibility, DNA extraction was conducted at a low temperature and immediately after exposure to 137 Cs, and a rapid genome detection method was established using the genome DNA. As the model genomes, the following three were used: 1) long chain repeated sequences widely dispersed over chromosome, 2) cluster genes, 3) single copy genes. The effects of radiation were detectable at 1-2 Gy for the long repeated sequences and at 7 Gy for the cluster genes, respectively, whereas no significant effects were observed at any Gy tested for the single copy genes. Amplification was marked in the cells exposed at 1-10 Gy (peak at 4 Gy), suggesting that these regions had

  16. DNA-repair after irradiation of cells with gamma-rays and neutrons

    International Nuclear Information System (INIS)

    Altmann, H.

    1975-11-01

    The structural alterations of calf thymus DNA produced by neutron or gamma irradiation were observed by absorption spectra, sedimentation rate and viscosity measurements. Mixed neutron-gamma irradiation produced fewer single and double strand breaks compared with pure gamma irradiation. RBE-values for mixed neutron-gamma radiation were less than 1, and DNA damage decreased with increasing neutron dose rate. Repair processes of DNA occuring after irradiation were measured in mouse spleen suspensions and human lymphocytes using autoradiographic methods and gradient centrifugations. The number of labelled cells was smaller after mixed neutron-gamma irradiation than after gamma irradiation. The rejoining of strand breaks in alkaline and neutral sucrose was more efficient after gamma irradiation than after mixed neutron-gamma irradiation. Finally, the effect of detergents Tween 80 and Nonident P40 on unscheduled DNA synthesis was studied by autoradiography after mixed neutron-gamma irradiation (Dn=5 krad). The results showed that the DNA synthesis was inhibited by detergent solutions of 0.002%

  17. The validity of sedimentation data from high molecular weight DNA and the effects of additives on radiation-induced single-strand breakage

    International Nuclear Information System (INIS)

    Dugle, D.L.

    1979-10-01

    The optimization of many of the factors governing reproducible sedimentation behaviour of high molecular weight single-strand DNA in a particular alkaline sucrose density gradient system is described. A range of angular momenta is defined for which a constant strand breakage efficiency is required, despite a rotor speed effect which increases the measured molecular weights at decreasing rotor speeds for larger DNA molecules. The possibility is discussed that the bimodal control DNA profiles obtained after sedimentation at 11 500 rev/min (12 400 g) or less represent structural subunits of the chromatid. The random induction of single-strand DNA breaks by ionizing radiation is demonstrated by the computer-derived fits to the experimental profiles. The enhancement of single-strand break (SSB) yields in hypoxic cells by oxygen, para-nitroacetophenone (PNAP), or any of the three nitrofuran derivatives used was well correlated with increased cell killing. Furthermore, reductions in SSB yields for known hydroxyl radical (OH.) scavengers correlates with the reactivities of these compounds toward OH.. This supports the contention that some type of OH.-induced initial lesion, which may ultimately be expressed as an unrepaired or misrepaired double-strand break, constitutes a lethal event. (author)

  18. Yield of radiation-induced DNA single-strand breaks in Escherichia coli and superinfecting phage lambda at different dose rates. Repair of strand breaks in different buffers

    International Nuclear Information System (INIS)

    Boye, E.; Johansen, I.; Brustad, T.

    1976-01-01

    Cells of E. coli K-12 strain AB 1886 were irradiated in oxygenated phosphate buffered saline at 2 0 C with electrons from a 4-MeV linear accelerator. The yield of DNA single-strand breaks was determined as a function of the dose rate between 2.5 and 21,000 krad/min. For dose rates over 100 krad/min the yield was found to be constant. Below 10 krad/min the yield of breaks decreases drastically. This is explained by rejoining of breaks during irradiation. Twenty percent of the breaks induced by acute exposure are repaired within 3 min at 2 0 C. Superinfecting phage lambda DNA is repaired at the same rate as chromosomal DNA. In contrast to the results obtained with phosphate-buffered saline, an increase in the number of breaks after irradiation is observed when the bacteria are suspended in tris buffer. It is suggested that buffers of low ionic strength facilitate the leakage through the membrane of a small-molecular-weight component(s) necessary for DNA strand rejoining

  19. Membrane phospholipids and radiation-induced death of mammalian cells

    International Nuclear Information System (INIS)

    Wolters, H.

    1987-01-01

    Radiation-induced cell killing is generally believed to be a consequence of residual DNA damage or damage that is mis-repaired. However, besides this DNA damage, damage to other molecules or structures of the cell may be involved in the killing. Especially membranes have been suggested as a determinant in cellular radiosensitivity. In this thesis experiments are described, dealing with the possible involvement of membranes in radiation-induced killing of mammalian cells. A general treatise of membrane structure is followed by information concerning deleterious effects of radiation on membranes. Consequences of damage to structure and function of membranes are reviewed. Thereafter evidence relating to the possible involvement of membranes in radiation-induced cell killing is presented. (Auth.)

  20. Dynamic alteration in H3 serine 10 phosphorylation is G1-phase specific during ionization radiation induced DNA damage response in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ajit K.; Bhattacharya, Saikat; Khan, Shafqat A.; Khade, Bharat; Gupta, Sanjay, E-mail: sgupta@actrec.gov.in

    2015-03-15

    Highlights: • Loss of H3S10P in response to DNA damage is a universal phenomenon from G1 cells. • The loss happens predominantly from histone H3.3, a transcription activation mark. • Compaction of chromatin occurs during repair stage of DDR. • The alteration of H3S10P shows an inverse correlation with γH2AX. - Abstract: Chromatin acts as a natural barrier in DNA-damage recognition and repair. Histones undergo differential post-translational modification(s) to facilitate DNA damage response (DDR). Importance of modifications like phosphorylation of histone variant H2A.X in DNA repair is very well understood, however, ambiguous results exist in literature regarding the levels of certain histone modifications and their possible role in repair. In the present study, we have investigated in depth the alteration in the level of the highly dynamic histone mark H3S10P as it plays a dual role in different phases of the cell cycle. We show here that H3S10P decreases specifically from irradiated G1-enriched cells irrespective of the damaging agent or the cell line used in the study. Interestingly, the loss occurs predominantly from H3.3 variant which is a transcription activation mark like H3S10P itself, suggesting that the alteration might be implicated in transcription repression. The decrease in other transcription marks like H3K9Ac, H3K14Ac, H3K56Ac and H3S28P along with the occurrence of chromatin condensation in response to DNA damage in G1 phase strengthens the hypothesis. In addition, the alteration in the level of H3S10P shows an inverse correlation with that of γH2AX in a dose-dependent manner and probably occurs from the same mononucleosome. We propose that the drop in the levels of histone H3S10 phosphorylation is a universal phenomenon in response to DNA damage and is a trigger to induce transcription repressive state to facilitate repair.

  1. Dynamic alteration in H3 serine 10 phosphorylation is G1-phase specific during ionization radiation induced DNA damage response in human cells

    International Nuclear Information System (INIS)

    Sharma, Ajit K.; Bhattacharya, Saikat; Khan, Shafqat A.; Khade, Bharat; Gupta, Sanjay

    2015-01-01

    Highlights: • Loss of H3S10P in response to DNA damage is a universal phenomenon from G1 cells. • The loss happens predominantly from histone H3.3, a transcription activation mark. • Compaction of chromatin occurs during repair stage of DDR. • The alteration of H3S10P shows an inverse correlation with γH2AX. - Abstract: Chromatin acts as a natural barrier in DNA-damage recognition and repair. Histones undergo differential post-translational modification(s) to facilitate DNA damage response (DDR). Importance of modifications like phosphorylation of histone variant H2A.X in DNA repair is very well understood, however, ambiguous results exist in literature regarding the levels of certain histone modifications and their possible role in repair. In the present study, we have investigated in depth the alteration in the level of the highly dynamic histone mark H3S10P as it plays a dual role in different phases of the cell cycle. We show here that H3S10P decreases specifically from irradiated G1-enriched cells irrespective of the damaging agent or the cell line used in the study. Interestingly, the loss occurs predominantly from H3.3 variant which is a transcription activation mark like H3S10P itself, suggesting that the alteration might be implicated in transcription repression. The decrease in other transcription marks like H3K9Ac, H3K14Ac, H3K56Ac and H3S28P along with the occurrence of chromatin condensation in response to DNA damage in G1 phase strengthens the hypothesis. In addition, the alteration in the level of H3S10P shows an inverse correlation with that of γH2AX in a dose-dependent manner and probably occurs from the same mononucleosome. We propose that the drop in the levels of histone H3S10 phosphorylation is a universal phenomenon in response to DNA damage and is a trigger to induce transcription repressive state to facilitate repair

  2. Damage to plasmid DNA produced by 60Co-gamma radiation and subsequent repair processes in E. coli with and without SOS induction

    International Nuclear Information System (INIS)

    Bien, M.

    1986-01-01

    This study was carried out to provide information on the question as to whether radiation-induced separation of double-stranded DNA in E. coli is followed by repair processes leading to the formation of replicable material. For the detection of those double-strand breaks, E. coli was first transformed using enzymatically linearised dBR 322-DNA. This served as a reference standard to compare the transformations using radiated DNA. DNA was either exposed to increasing doses of 60 Co-gamma radiation or separated into one oc-fraction and one lin-fraction following exposure to 30 Gy. The DNA samples thus obtained were then used to transform three different strains of E. coli (wild strain, SFX, SFXrecA - ). In order to improve the repair yield, the cells were additionally SOS-induced using ultraviolet radiation. The mutation rates were a measure of the number of errors occurring during the various repair processes. Restriction analysis was carried out to characterise the resulting mutants in greater detail. (orig./MG) [de

  3. Recruitment of HP1 beta to UVA-induced DNA lesions is independent of radiation-induced changes in A-type lamins

    Czech Academy of Sciences Publication Activity Database

    Sehnalová, Petra; Legartová, Soňa; Cmarko, D.; Kozubek, Stanislav; Bártová, Eva

    2014-01-01

    Roč. 106, č. 5 (2014), s. 151-165 ISSN 0248-4900 R&D Projects: GA ČR(CZ) GAP302/10/1022; GA ČR(CZ) GBP302/12/G157; GA ČR(CZ) GA13-07822S Institutional support: RVO:68081707 Keywords : Chromatin * DNA damage * HP1 Subject RIV: BO - Biophysics Impact factor: 3.506, year: 2014

  4. Direct assays of radiation-induced DNA base lesions in mammalian cells: Technical progress report, July 1, 1986--December 1, 1988

    International Nuclear Information System (INIS)

    Wheeler, K.T. Jr.

    1988-01-01

    Our cesium irradiator was installed in April 1987 and has the capability of irradiating DNA solutions, cells and animals at dose rates from >60 Gy/min to <10/sup /minus/2/ Gy/min. By early summer all of the dosimetry and set-ups were established to perform this research. In may 1987, Dr. Krystyna Lesiak left to return to the National Institutes of Health. However, she has remained a collaborator over the past 1/1/2/ years. She has synthesized a large lot of α-deoxyadenosine, isolated a large batch of both the R and S isomer of cyclodeoxyadenosine and has capped the α-deoxyadenonsine for use in a DNA synthesizer that uses phosphoramidite chemistry. In November 1987, Dr. Andrzej Surowiec joined our unit as a Visiting Research Assistant Professor. Dr. Surowiec has a MS degree in electrical engineering and did his Ph.D. in Biophysics studying the conductivity of DNA in dilute solution. He has been performing the helix-coil transition experiments. In November 1987, Dr. Steven Swarts also joined our unit as a Postdoctoral Fellow. He received his Ph.D. from Oakland University under Dr. Michael Sevilla with whom we have a collaboration studying the induction of base damage in hydrated DNA. Dr. Swarts has a strong background in spectroscopy and, therefore, was a key individual for determination of the limitations of the HPLC assays and the establishment of a GC/MS capability equivalent to Dr. M. Dizdaroglu at the National Bureau of Standards. 9 refs., 1 tab

  5. Feasibility of measuring radiation-induced DNA double strand breaks and their repair by pulsed field gel electrophoresis in freshly isolated cells from the mouse RIF-1 tumor

    International Nuclear Information System (INIS)

    Waarde, Maria A.W.H. van; Assen, Annette J. van; Konings, Antonius W.T.; Kampinga, Harm H.

    1996-01-01

    Purpose: To examine the technical feasibility of pulsed field gel electrophoresis (PFGE) as a predictive assay for the radio responsiveness of tumors. Induction and repair of DNA double strand breaks (DSBs) in a freshly prepared cell suspension from a RIF-1 tumor (irradiated ex vivo) was compared with DSB induction and repair in exponentially growing RIF-1 cells in culture (irradiated in vitro). Methods and Materials: A murine RIF-1 tumor grown in vivo was digested, and cells were exposed to x-rays (ex vivo) at doses of 1 to 75 Gy. DNA damage was measured using CHEF (clamped homogeneous electric fields) electrophoresis. Repair kinetics were studied at 37 deg. C for 4 h after irradiation. Radiosensitivity was determined by clonogenic assay, and cell cycle distributions by flow cytometry. For comparison, a trypsinized suspension of exponentially growing RIF-1 cells in vitro was run parallel with each ex vivo experiment. Results: Induction of DSBs, expressed as % DNA extracted from the plug, was similar in the in vitro and ex vivo irradiated cells. Compared to repair rates in in vitro cultured RIF-1 cells, repair kinetics in a freshly prepared cell suspension from the tumor were decreased, unrelated to differences in radiosensitivity. Differences in repair could not be explained by endogenous DNA degradation, nor by influences of enzymes used for digestion of the tumor. A lower plating efficiency and differences in ploidy (as revealed by flow cytometry) were the only reproducible differences between in vivo and in vitro grown cells that may explain the differences in repair kinetics. Conclusions: The current results do not support the idea that PFGE is a technique robust enough to be a predictive assay for the radiosensitivity of tumor cells

  6. Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis.

    Science.gov (United States)

    Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

    2017-10-27

    Radiation therapy induces DNA damage and inflammation leading to fibrosis. Fibrosis can occur 4 to 12 months after radiation therapy. This process worsens with time and years. Radiation-induced fibrosis is characterized by fibroblasts proliferation, myofibroblast differentiation, and synthesis of collagen, proteoglycans and extracellular matrix. Myofibroblasts are non-muscle cells that can contract and relax. Myofibroblasts evolve towards irreversible retraction during fibrosis process. In this review, we discussed the interplays between transforming growth factor-β1 (TGF-β1), canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR γ) in regulating the molecular mechanisms underlying the radiation-induced fibrosis, and the potential role of PPAR γ agonists. Overexpression of TGF-β and canonical WNT/β-catenin pathway stimulate fibroblasts accumulation and myofibroblast differentiation whereas PPAR γ expression decreases due to the opposite interplay of canonical WNT/β-catenin pathway. Both TGF-β1 and canonical WNT/β-catenin pathway stimulate each other through the Smad pathway and non-Smad pathways such as phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) signaling. WNT/β-catenin pathway and PPAR γ interact in an opposite manner. PPAR γ agonists decrease β-catenin levels through activation of inhibitors of the WNT pathway such as Smad7, glycogen synthase kinase-3 (GSK-3 β) and dickkopf-related protein 1 (DKK1). PPAR γ agonists also stimulate phosphatase and tensin homolog (PTEN) expression, which decreases both TGF-β1 and PI3K/Akt pathways. PPAR γ agonists by activating Smad7 decrease Smads pathway and then TGF-β signaling leading to decrease radiation-induced fibrosis. TGF-β1 and canonical WNT/β-catenin pathway promote radiation-induced fibrosis whereas PPAR γ agonists can prevent radiation-induced fibrosis.

  7. Development of a radiation track structure clustering algorithm for the prediction of DNA DSB yields and radiation induced cell death in Eukaryotic cells.

    Science.gov (United States)

    Douglass, Michael; Bezak, Eva; Penfold, Scott

    2015-04-21

    The preliminary framework of a combined radiobiological model is developed and calibrated in the current work. The model simulates the production of individual cells forming a tumour, the spatial distribution of individual ionization events (using Geant4-DNA) and the stochastic biochemical repair of DNA double strand breaks (DSBs) leading to the prediction of survival or death of individual cells. In the current work, we expand upon a previously developed tumour generation and irradiation model to include a stochastic ionization damage clustering and DNA lesion repair model. The Geant4 code enabled the positions of each ionization event in the cells to be simulated and recorded for analysis. An algorithm was developed to cluster the ionization events in each cell into simple and complex double strand breaks. The two lesion kinetic (TLK) model was then adapted to predict DSB repair kinetics and the resultant cell survival curve. The parameters in the cell survival model were then calibrated using experimental cell survival data of V79 cells after low energy proton irradiation. A monolayer of V79 cells was simulated using the tumour generation code developed previously. The cells were then irradiated by protons with mean energies of 0.76 MeV and 1.9 MeV using a customized version of Geant4. By replicating the experimental parameters of a low energy proton irradiation experiment and calibrating the model with two sets of data, the model is now capable of predicting V79 cell survival after low energy (cell survival probability, the cell survival probability is calculated for each cell in the geometric tumour model developed in the current work. This model uses fundamental measurable microscopic quantities such as genome length rather than macroscopic radiobiological quantities such as alpha/beta ratios. This means that the model can be theoretically used under a wide range of conditions with a single set of input parameters once calibrated for a given cell line.

  8. Radiation-induced mutation at minisatellite loci

    International Nuclear Information System (INIS)

    Dubrova, Y.E.; Nesterov, V.N.; Krouchinsky, N.G.

    1997-01-01

    We are studying the radiation-induced increase of mutation rate in minisatellite loci in mice and humans. Minisatellite mutations were scored by multilocus DNA fingerprint analysis in the progeny of γ-irradiated and non-irradiated mice. The frequency of mutation in offspring of irradiated males was 1.7 higher that in the control group. Germline mutation at human minisatellite loci was studied among children born in heavily polluted areas of the Mogilev district of Belarus after the Chernobyl accident and in a control population. The frequency of mutation assayed both by DNA fingerprinting and by eight single locus probes was found to be two times higher in the exposed families than in the control group. Furthermore, mutation rate was correlated with the parental radiation dose for chronic exposure 137 Cs, consistent with radiation-induction of germline mutation. The potential use of minisatellites in monitoring germline mutation in humans will be discussed

  9. [Direct assays of radiation-induced DNA base lesions in mammalian cells.] Final progress report, February 1, 1984-June 30, 1986

    International Nuclear Information System (INIS)

    Wheeler, K.T.

    1986-01-01

    Adenine (Ade), 2'-deoxyadenosine (dAdo) and 5'-deoxyadenosine monophosphate (5'-dAMP) were irradiated with 50 to 15,000 Gy under oxic and hypoxic conditions. HPLC procedures providing satisfactory separation of the adenine damage products formed during irradiation of DNA model compounds were found. Structures of some of the damage products were confirmed to include 8-OHAde, 4,6-diamino-5-formamidopyrimidine, and 8-OH-5'-dAMP. Two damage products of dAdo (8-OHdAdo and the major isomer of 8,5'-cdAdo), the formation of which depends on the presence or absence of oxygen, were determined quantitatively by HPLC. The limit for HPLC detection was estimated as 4 to 50 pmoles for these compounds. This corresponds to a detection limit of about 50 Gy in radiation dose units. These two products were also detected in mixtures of all four nucleosides irradiated with 50 Gy

  10. The Effects of Topically Applied Glycolic Acid and Salicylic Acid on Ultraviolet Radiation-Induced Erythema, DNA Damage and Sunburn Cell Formation in Human Skin

    Science.gov (United States)

    Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G.; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z.; Miller, Sharon A.; Hearing, Vincent J.

    2009-01-01

    Background α-Hydroxy acids (αHA) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that αHA can increase the sensitivity of skin to ultraviolet radiation. More recently, β-hydroxy acids (βHA), or combinations of αHA and βHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing β-HA. Objective To determine whether topical treatment with glycolic acid, a representative αHA, or with salicylic acid, a βHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Methods Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday - Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all 4 sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Results Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Conclusions Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not. PMID:19411163

  11. Construction of radiation - induced metastasis model in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Kuk; Jang, Su Jin; Kang, Sung Wook; Kim, Jae Sung; Hwang, Sang Gu; Kang, Joo Hyun [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2011-05-15

    In treatment of cancer, distant metastases are important limiting factor because an estimated 50% of all cancer patients will develop metastases, and the metastases are major causing of cancer treatment failure. Recently a few reports indicated {gamma}-radiation induced an increase of invasiveness of several cancer cells. In this study, we had tried to show the possibility that radiation could also induce metastasis in vivo system. To prove our hypothesis, we constructed primary tumor by using C6-TL transfectant cell line expressing HSV1-tk and firefly luciferase (fLuc), and then {gamma}-radiation was treated to xenografts locally. Treatment of {gamma}-radiation to primary C6-TL xenografts of mice reduced size of xenografts and elongated survival of mice than those of mock control mice. But we also show that {gamma}-radiation treatment was followed by the growth of dormant metastases in various organs including lung and intestine after 2-4 weeks of {gamma}-radiation treatment. When bioluminescence imaging indicated growth of tumor in organs in mice, we sacrificed the mice and repeat acquired bioluminescence imaging after repeatedly. These images presented tumor growth locations exactly in organs. Because metastatic tumor candidates have morphology of foci, biopsies were performed for histological analysis or PCR analysis to confirm metastases. In most foci, histological analysis indicated several features of typical cancer tissue and PCR analysis showed present of fLuc gene in metastases. Detection of fLuc gene in metastases indicated these foci were originated from primary C6-TL xenografts, and the results suggest that {gamma}-radiation could promote metastasis in vivo as well as in vitro system. Although we need to understand changes of intracellular signaling or physiological phenomena of the radiation-induced metastasis yet, these results also imply that {gamma}-radiation treatment only to cancer patients need to pay attention carefully, and development of new

  12. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation. I. Initial characterization of DNA damage, micronucleus formation, apoptosis, cell survival, and cell cycle phase redistribution

    Science.gov (United States)

    Green, L. M.; Murray, D. K.; Bant, A. M.; Kazarians, G.; Moyers, M. F.; Nelson, G. A.; Tran, D. T.

    2001-01-01

    The RBE of protons has been assumed to be equivalent to that of photons. The objective of this study was to determine whether radiation-induced DNA and chromosome damage, apoptosis, cell killing and cell cycling in organized epithelial cells was influenced by radiation quality. Thyroid-stimulating hormone-dependent Fischer rat thyroid cells, established as follicles, were exposed to gamma rays or proton beams delivered acutely over a range of physical doses. Gamma-irradiated cells were able to repair DNA damage relatively rapidly so that by 1 h postirradiation they had approximately 20% fewer exposed 3' ends than their counterparts that had been irradiated with proton beams. The persistence of free ends of DNA in the samples irradiated with the proton beam implies that either more initial breaks or a quantitatively different type of damage had occurred. These results were further supported by an increased frequency of chromosomal damage as measured by the presence of micronuclei. Proton-beam irradiation induced micronuclei at a rate of 2.4% per gray, which at 12 Gy translated to 40% more micronuclei than in comparable gamma-irradiated cultures. The higher rate of micronucleus formation and the presence of larger micronuclei in proton-irradiated cells was further evidence that a qualitatively more severe class of damage had been induced than was induced by gamma rays. Differences in the type of damage produced were detected in the apoptosis assay, wherein a significant lag in the induction of apoptosis occurred after gamma irradiation that did not occur with protons. The more immediate expression of apoptotic cells in the cultures irradiated with the proton beam suggests that the damage inflicted was more severe. Alternatively, the cell cycle checkpoint mechanisms required for recovery from such damage might not have been invoked. Differences based on radiation quality were also evident in the alpha components of cell survival curves (0.05 Gy(-1) for gamma rays, 0

  13. Dose rate effectiveness in radiation-induced teratogenesis in mice

    International Nuclear Information System (INIS)

    Kato, F.; Ootsuyama, A.; Norimura, T.

    2000-01-01

    To investigate the role of p53 gene in tissue repair of teratogenic injury, we compared incidence of radiation-induced malformations in homozygous p53(-/-) mice, heterozygous p53(+/-) mice and wild-type p53(+/+) mice. After X-irradiation with 2 Gy at high dose rate on 9.5 days of gestation, p53(-/-) mice showed higher incidences of anomalies and higher resistance to prenatal deaths than p53(+/+) mice. This reciprocal relationship of radiosensitivity to anomalies and deaths supports the notion that embryos or fetuses have a p53-dependent 'guardian' that aborts cells bearing radiation-induced teratogenic DNA damage. In fact, after X-irradiation, the number of apoptotic cells was greatly increased in p53(+/+) fetuses but not in p53(-/-) fetuses. The same dose of γ-ray exposure at low dose rate on 9.5-10.5 day of gestation produced significant reduction of radiation-induced malformation in p53(+/+) and p53(+/-) mice, remained teratogenic for p53(-/-) mice. These results suggest that complete elimination of teratogenic damage from irradiated tissues requires the concerted cooperation of two mechanisms; proficient DNA repair and the p53-dependent apoptotic tissue repair. When concerted DNA repair and apoptosis functions efficiently, there is a threshold dose-rate for radiation-induced malformations. (author)

  14. Radiation induced crosslinking of polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Oshima, Akihiro; Tabata, Yoneho; Ikeda, Shigetoshi; Otsuhata, Kazushige; Kudoh, Hisaaki; Seguchi, Tadao.

    1995-01-01

    The Irradiation temperature effect on polytetrafluoroethylene (PTFE) from room temperature to 380degC was investigated by tensile test and thermal analysis. The behavior of tensile properties and changes of crystallinity on irradiation indicated the formation of a network structure in PTFE by radiation induced crosslinking in inert gas in the molten state just above the melting temperature of PTFE (327degC). The crosslinked PTFE showed a much improved radiation resistance in an atmospheric radiation field. (author)

  15. Radiation-induced chromosomal instability

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, S. [GSI, Biophysics, Darmstadt (Germany)

    1999-03-01

    Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/{mu}m) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

  16. Radiation-induced heart injury

    International Nuclear Information System (INIS)

    Suzuki, Yoshihiko; Niibe, Hideo

    1975-01-01

    In order to identify radiation-induced heart injury and to differentiate it from heart disease, an attempt was made to clarify post-irradiation heart injury by investigating the histological changes which occur during the internal between the irradiation and the time of demonstrable histological changes. A study was made of 83 autopsies in which most of the primary neoplasms were breast cancers, lung cancers and mediastinal tumors. In 43 of these autopsies the heart had been irradiated. Sixty eight dd-strain mice were also used for microautoradiographic study. Histological changes in the heart were observed in 27 of the 43 cases receiving irradiation. The limit of the tolerance dose to the heart for indicating histological changes was 1220 ret in humans. The latent period without histological changes was 2.7 months after initiation of radiation therapy. Greater heart injury was observed after re-irradiation or after the combined therapy of radiation and chemotherapy especially mitomycin (MMC). The histological findings after treatment with MMC were similar to those of radiation-induced heart injury. Results of the study indicate that the damage is secondary to radiation-induced changes of the vascula connective tissue. (Evans, G.)

  17. Effects of physical, chemical or biological factors on DNA replication in mammalian cells. Part 2. Recovery of DNA complex, nucleoid and DNA replication after gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Synzynys, B.I.; Kiseleva, V.I.; Trofimova, S.F.

    1984-11-01

    Murine LL cell line was employed in studies on the effects of gamma irradiation (6 Gy, 8 Gy/min from Co-60 source) on the kinetics and repair of DNA superstructure and recovery of DNA synthesis. Comparison of the kinetic data for the postradiation repair of the DNA-membrane complex, nucleoid, and recovery of DNA synthesis demonstrated that functional recovery of the former two factors preceded DNA synthesis by at least 2 h. In view of this lag, it appears that additional factors are involved in radiation damage that must be repaired before DNA synthesis commences. 10 references, 3 figures.

  18. Specific inhibition of Wee1 kinase and Rad51 recombinase: A strategy to enhance the sensitivity of leukemic T-cells to ionizing radiation-induced DNA double-strand breaks

    Energy Technology Data Exchange (ETDEWEB)

    Havelek, Radim, E-mail: radim.havelek@upce.cz [Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10 (Czech Republic); Cmielova, Jana [Department of Medical Biochemistry, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Simkova 870, Hradec Kralove 500 38 (Czech Republic); Kralovec, Karel; Bruckova, Lenka; Bilkova, Zuzana; Fousova, Ivana [Department of Biological and Biochemical Sciences, Faculty of Chemical Technology, University of Pardubice, Studentska 573, Pardubice 532 10 (Czech Republic); Sinkorova, Zuzana; Vavrova, Jirina [Department of Radiobiology, Faculty of Military Health Sciences, University of Defence in Brno, Trebesska 1575, Hradec Kralove 500 01 (Czech Republic); Rezacova, Martina [Department of Medical Biochemistry, Faculty of Medicine in Hradec Kralove, Charles University in Prague, Simkova 870, Hradec Kralove 500 38 (Czech Republic)

    2014-10-24

    Highlights: • Pre-treatment with the inhibitors increased the sensitivity of Jurkat cells to irradiation. • Combining both inhibitors together resulted in a G2 cell cycle arrest abrogation in Jurkat. • Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. • Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction in MOLT-4 cells. • When dosed together, the combination decreased MOLT-4 cell survival. - Abstract: Present-day oncology sees at least two-thirds of cancer patients receiving radiation therapy as a part of their anticancer treatment. The objectives of the current study were to investigate the effects of the small molecule inhibitors of Wee1 kinase II (681641) and Rad51 (RI-1) on cell cycle progression, DNA double-strand breaks repair and apoptosis following ionizing radiation exposure in human leukemic T-cells Jurkat and MOLT-4. Pre-treatment with the Wee1 681641 or Rad51 RI-1 inhibitor alone increased the sensitivity of Jurkat cells to irradiation, however combining both inhibitors together resulted in a further enhancement of apoptosis. Jurkat cells pre-treated with inhibitors were positive for γH2AX foci 24 h upon irradiation. MOLT-4 cells were less affected by inhibitors application prior to ionizing radiation exposure. Pre-treatment with Rad51 RI-1 had no effect on apoptosis induction; however Wee1 681641 increased ionizing radiation-induced cell death in MOLT-4 cells.

  19. Gene expression and hormone autonomy in radiation-induced tumors of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Persinger, S.M.; Town, C.D.

    1989-01-01

    In order to study the molecular genetics of factor controlling plant cell growth, we have isolated a group of radiation-induced tumors from Arabidopsis thaliana. Tumors appeared on plants derived from 60 Co gamma-irradiated seed or seedlings, and are capable of hormone-autonomous growth in culture. We have used vertebrate oncogene probes to explore the hypothesis that the tumors arose by the radiation-induced activation of growth-regulating plant oncogenes. One probe, int-2, was used to isolate cDNA clones representing an mRNA differentially expressed between tumors and hormone-dependent callus tissue. The genomic organization and function of this and other differentially expressed Arabidopsis sequences are being further characterized. A second area of study concerns the hormonal status of individual tumors. Tumor tissue varies in color, texture, and degree of differentiation: while some tumors appear undifferentiated, one consistently produces roots, and others occasionally develop shoots or leaflets. The tumors have characteristic growth rates on hormone-free medium, and growth in response to exogenous hormones differs among the tumors themselves and from wild-type. Characterization of the relationships between hormonal status, morphogenesis, and gene expression should yield valuable insights into the mechanisms regulating plant growth and development

  20. Radiation-induced cardiovascular effects

    Science.gov (United States)

    Tapio, Soile

    Recent epidemiological studies indicate that exposure to ionising radiation enhances the risk of cardiovascular mortality and morbidity in a moderate but significant manner. Our goal is to identify molecular mechanisms involved in the pathogenesis of radiation-induced cardiovascular disease using cellular and mouse models. Two radiation targets are studied in detail: the vascular endothelium that plays a pivotal role in the regulation of cardiac function, and the myocardium, in particular damage to the cardiac mitochondria. Ionising radiation causes immediate and persistent alterations in several biological pathways in the endothelium in a dose- and dose-rate dependent manner. High acute and cumulative doses result in rapid, non-transient remodelling of the endothelial cytoskeleton, as well as increased lipid peroxidation and protein oxidation of the heart tissue, independent of whether exposure is local or total body. Proteomic and functional changes are observed in lipid metabolism, glycolysis, mitochondrial function (respiration, ROS production etc.), oxidative stress, cellular adhesion, and cellular structure. The transcriptional regulators Akt and PPAR alpha seem to play a central role in the radiation-response of the endothelium and myocardium, respectively. We have recently started co-operation with GSI in Darmstadt to study the effect of heavy ions on the endothelium. Our research will facilitate the identification of biomarkers associated with adverse cardiac effects of ionising radiation and may lead to the development of countermeasures against radiation-induced cardiac damage.

  1. Heavy-ion radiation induced bystander effect in mice

    Science.gov (United States)

    Liang, Shujian; Sun, Yeqing; Zhang, Meng; Wang, Wei; Cui, Changna

    2012-07-01

    Radiation-induced bystander effect is defined as the induction of damage in neighboring non-hit cells by signals released from directly-irradiated cells. Recently, Low dose of high LET radiation induced bystander effects in vivo have been reported more and more. It has been indicated that radiation induced bystander effect was localized not only in bystander tissues but also in distant organs. Genomic, epigenetic, metabolomics and proteomics play significant roles in regulating heavy-ion radiation stress responses in mice. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male mice head were exposed to 2000mGy dose of 12C heavy-ion radiation and the distant organ liver was detected on 1h, 6h, 12h and 24h after radiation, respectively. MSAP was used to monitor the level of polymorphic DNA methylation changes. The results show that heavy-ion irradiate mouse head can induce liver DNA methylation changes significantly. The percent of DNA methylation changes are time-dependent and highest at 6h after radiation. We also prove that the hypo-methylation changes on 1h and 6h after irradiation. But the expression level of DNA methyltransferase DNMT3a is not changed. UPLC/Synapt HDMS G2 was employed to detect the proteomics of bystander liver 1h after irradiation. 64 proteins are found significantly different between treatment and control group. GO process show that six of 64 which were unique in irradiation group are associated with apoptosis and DNA damage response. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in distant organ liver. Moreover, our findings are important to understand the molecular mechanism of radiation induced bystander effects in vivo.

  2. Electrical conduction and photoresponses of gamma-ray-irradiated single-stranded DNA/single-walled carbon nanotube composite systems

    Energy Technology Data Exchange (ETDEWEB)

    Hong, W.; Lee, E.M.; Kim, D.W.; Lee, Cheol Eui, E-mail: rscel@korea.ac.kr

    2015-04-15

    Highlights: •Effects of gamma-ray irradiation on single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite films. •Barrier for thermally activated conduction in the composite systems modified by the gamma-ray irradiation. •Photoresponses reveal photoexcitation and oxygen photodesorption modified by gamma-ray irradiation. -- Abstract: Effects of gamma-ray irradiation on the electrical conductivity and photoresponse have been studied for single-stranded DNA (ssDNA)/single-walled carbon nanotube (SWNT) composite films. The temperature-dependent electrical conductivity of the ssDNA/SWNT composite films, well described by a fluctuation-induced tunneling model, indicated modification of the barrier for thermally activated conduction by the gamma-ray irradiation. Besides, the photoresponse measurements indicated modified photoexcited charge carrier generation and oxygen photodesorption in the composite systems due to the gamma-ray irradiation.

  3. Radiation Induced Color Centers in a La Doped PWO Crystal

    CERN Document Server

    Deng, Qun

    1998-01-01

    This report presents result of a study on radiation induced color center densities in a La doped lead tungstate ( PWO) crystal. The creation and annihilation constants of radiation induced color centers were determined by using transmittance data measured for a PWO sample before and during Co-60 gamma ray irradiation at a dose rate of 15 rad/hr. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/hr. The result was found to be in a good agreement with experimental data, indicating that this model of color center kinetics can be used to predict behavior of PWO crystals under irradiation.

  4. Treatment of Radiation Induced Biological Changes by Bone Marrow Transplantation

    International Nuclear Information System (INIS)

    El-Missiry, M.A.; Shehata, G.; Roushdy, H.M; Fayed, Th.A.

    1999-01-01

    Preventing the propagation of radiation induced oxidative damage has been a subject of considerable investigations. The ultimate goal of the present study is to use bone marrow cells to ameliorate or to treat the radiation sickness. Transplantation of bone marrow cell has shown promising results in the present experimental radiation treatment. In this report, suspension of bone marrow cells was injected into rats 12 h. after exposure to 4.5 Gy whole body gamma irradiation. Significant results were recorded on the successful control of the radiation induced disorders in a number of biochemical parameters including certain enzymatic and nonenzymatic antioxidants (superoxide dismutase and glutathione) and certain parameters related to kidney function including creatinine, urea as well as Atpase Activity in blood serum, urine and kidney tissue

  5. Improvement of boiling heat transfer by radiation induced boiling enhancement

    International Nuclear Information System (INIS)

    Imai, Yasuyuki; Okamoto, Koji; Madarame, Haruki; Takamasa, Tomoji

    2003-01-01

    For nuclear reactor systems, the critical heat flux (CHF) data is very important because it limits reactor efficiency. Improvement of CHF requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. In our previous study, we confirmed that the surface wettability changed significantly or that highly hydrophilic conditions were achieved, after irradiation of 60 Co gamma ray, by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of RISA on boiling phenomena, surface wettability in a high-temperature environment and critical heat flux (CHF) of metal oxides irradiated by gamma rays were investigated. A CHF experiment in the pool boiling condition was carried out under atmospheric pressure. The heating test section made of titanium was 0.2 mm in thickness, 3 mm in height, and 60 mm in length. Oxidation of the surface was carried out by plasma jetting for 40 seconds. The test section was irradiated by 60 Co gamma ray with predetermined radiation intensity and period. The CHF of oxidized titanium was improved up to 100 percent after 800 kGy 60 Co gamma ray irradiation. We call this effect Radiation Induced Boiling Enhancement (RIBE). Before we conducted the CHF experiment, contact angles of the test pieces were measured to show the relationship between wettability and CHF. The CHF in the present experiment increases will surface wettability in the same manner as shown by Liaw and Dhir's results. (author)

  6. 5-AED Enhances Survival of Irradiated Mice in a G-CSF-Dependent Manner, Stimulates Innate Immune Cell Function, Reduces Radiation-Induced DNA Damage and Induces Genes that Modulate Cell Cycle Progression and Apoptosis

    Science.gov (United States)

    2012-07-22

    radiation- accident environment: the effect of sup- portive care plus administration of G-CSF. Health Phys 2005;89:546–55. 24. Singh VK, Grace MB...et al. Human in vivo radiation-induced biomarkers: gene expression changes in radiotherapy patients. Cancer Res 2004;64:6368–71. 74. Grace MB, McLeland

  7. Radiation induced mutations for breeding of sorghum

    International Nuclear Information System (INIS)

    Bretaudeau, A.

    1997-01-01

    Several sorghum cultivars of Mali were irradiated with different doses of gamma rays and compared with the Caudatum types. Radio-sensitivity studies suggested that the local types were less sensitive to radiation than the introduced types. Whereas the local varieties survived dose of 300 Gy, in Caudatum types, seed germination and growth were significantly reduced at 200 Gy. Several agronomically important mutants were obtained among the progeny of the local types. Some of the mutants were shorter and had improved panicle characteristics. Radiation-induced variation was observed in several characters such as plant height, resistance to lodging, plant architecture, drought tolerance, panicle length and compactness, seed size and color, seed quality (viterous or floury) and protein content, glume color and structure, flowering data (early and late maturity), and tillering capacity. One mutant was drought tolerant. Promising mutants were selected and are presently under evaluation in the National List Trials to confirm their potential and future release. Selected variants have been also crossed with local types to obtain promising material. (author). 8 refs, 2 tabs

  8. Radiation-induced heterophase polymerizations

    International Nuclear Information System (INIS)

    Carenza, M.; Palma, G.

    1985-01-01

    Investigations were carried out on the morphology of particles produced in the early stages of radiation-induced heterophase polymerization of acrylonitrile in quiescent conditions over a wide temperature range both in bulk and with addition of a solvent or a comonomer. The data were compared with the corresponding data obtained in the polymerization of vinyl chloride, producing an amorphous polymer, taking into account also the kinetic behaviours of the two polymerization systems. The particle morphologies in the two systems were quite similar at low polymerization temperatures but there were considerable differences when higher temperatures were involved. This change was interpreted on the basis of differences in compatability between the liquid phase and the polymer particle phase for the two systems. In order to account for the two different kinetic behaviours, a two-phase polymerization model was formulated and also a polymerization model in which the surface of the polymer particles was the locus of polymerization. (author)

  9. Experimental radiation-induced leukemia

    International Nuclear Information System (INIS)

    Upton, A.C.

    1977-01-01

    Of the various neoplasms induced by ionizing radiation in human and animal populations, leukemias and lymphomas were among the first to receive systematic study and have remained under intensive investigation up to the present time. The reticular tissue neoplasm that has been the most thoroughly studied is a lymphoma of the thymus which characteristically predominates in whole- bodyirradiated mice. Thanks to intensive research on this tumor, much is now known about its pathogenesis. The purpose of this report is to review the knowledge of pathogenesis of other types of radiation-induced leukemias and lymphomas, in an effort to assess the extent to which the comparative data for all such diseases can be integrated into a single unifying framework

  10. Melatonin against radiation induced free radicals: a study on tissues of Swiss albino mice

    International Nuclear Information System (INIS)

    Bhatia, A.L.; Manda, K.

    2003-01-01

    Full text: Antioxidant enzymes are part of the primary cellular defense against free radicals generated by radiation. Reports on low level chronic administration of melatonin with its antiradiation influence are scanty. Although compelling logic suggests that melatonin may be effective for a variety of disorders, the mode and optimal dose of melatonin is still not clear. Most studies have used doses of supraphysiological blood levels. Present investigation reports that melatonin in relatively lower concentrations increases the mRNA of both superoxide dismutases (SODs) and glutathione peroxidase (GSH-Px) and mediates possibly through receptors. The influence of low dose chronic administration (0.10 mg/Kg body weight/day for 15 days) of melatonin was studied against radiation-induced oxidative stress in 6 to 8 weeks old mice. Just after 24 hours of the last dose in various tissues viz. brain, liver, spleen and kidney were studied for lipid peroxidation, reduced glutathione (GSH), glutathione disulphide (GSSG), glutathione peroxidase (GSH-Px), protein, RNA, DNA and serum phosphatase activity. Radiation induced augmentation in the level of lipid peroxidation, glutathione disulphide (GSSG) and acid phosphatase was significantly ameliorated by pre-irradiation treatment with melatonin. Radiation induced depletion in the level of reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and alkaline phosphatase is significantly averted by melatonin administration. Regression analysis of survival data yielded LD50/30 as 7.16 Gy and 11Gy for control (irradiation alone) and experimental (melatonin + irradiation), respectively. Animals produced a dose reduction factor (DRF) as 1.53. Radiation induced deficit in the body and organ weight was also significantly thwarted in the melatonin pre-treated mice. Results indicate the antioxidative properties of melatonin against the gamma radiation. The findings support the results showing melatonin as a free radical scavenger, and

  11. Delayed Radiation-Induced Vasculitic Leukoencephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, Philipp J. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Faculty of Medicine, University of Heidelberg, Heidelberg (Germany); Park, Henry S. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Knisely, Jonathan P.S. [Department of Radiation Medicine, North Shore University Hospital, Manhasset, New York (United States); Chiang, Veronica L. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Vortmeyer, Alexander O., E-mail: alexander.vortmeyer@yale.edu [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States)

    2012-05-01

    Purpose: Recently, single-fraction, high-dosed focused radiation therapy such as that administered by Gamma Knife radiosurgery has been used increasingly for the treatment of metastatic brain cancer. Radiation therapy to the brain can cause delayed leukoencephalopathy, which carries its own significant morbidity and mortality. While radiosurgery-induced leukoencephalopathy is known to be clinically different from that following fractionated radiation, pathological differences are not well characterized. In this study, we aimed to integrate novel radiographic and histopathologic observations to gain a conceptual understanding of radiosurgery-induced leukoencephalopathy. Methods and Materials: We examined resected tissues of 10 patients treated at Yale New Haven Hospital between January 1, 2009, and June 30, 2010, for brain metastases that had been previously treated with Gamma Knife radiosurgery, who subsequently required surgical management of a symptomatic regrowing lesion. None of the patients showed pathological evidence of tumor recurrence. Clinical and magnetic resonance imaging data for each of the 10 patients were then studied retrospectively. Results: We provide evidence to show that radiosurgery-induced leukoencephalopathy may present as an advancing process that extends beyond the original high-dose radiation field. Neuropathologic examination of the resected tissue revealed traditionally known leukoencephalopathic changes including demyelination, coagulation necrosis, and vascular sclerosis. Unexpectedly, small and medium-sized vessels revealed transmural T-cell infiltration indicative of active vasculitis. Conclusions: We propose that the presence of a vasculitic component in association with radiation-induced leukoencephalopathy may facilitate the progressive nature of the condition. It may also explain the resemblance of delayed leukoencephalopathy with recurring tumor on virtually all imaging modalities used for posttreatment follow-up.

  12. Further characterization of the reverse transcriptase associated with porcine (radiation-induced) retroviruses

    International Nuclear Information System (INIS)

    Frazier, M.E.; Mallavia, L.P.; Hooper, M.J.

    1980-01-01

    Differential centrifugation and affinity chromatography were used to purify the porcine, radiation-induced retrovirus, RNA-dependent DNA polymerase. The purified RDDP was taken differentiated from cellular DNA polymerase γ by its template specificity, chromatographic characteristics, and the optimum reaction conditions required for DNA synthesis

  13. Difference in melting profiles of gamma irradiated DNA from chicken erythrocytes and from Escherichia coli B/r

    International Nuclear Information System (INIS)

    Kopff, J.; Miller, G.; Leyko, W.

    1977-01-01

    Effects of gamma irradiation on melting curves of DNA from chicken erythrocytes and Escherichia coli B/r were compared. Considerable changes, following gamma irradiation in the case of chicken erythrocytes DNA and no changes in the case of DNA from Escherichia coli B/r were observed. To explain the lack of changes in gamma irradiated samples of DNA from Escherichia coli B/r it was assumed that the original effects of irradiation were obscured by the process of renaturation of DNA. To exclude the above mentioned effect, examination of gamma irradiated DNA from Escherichia coli B/r was carried out with the addition of formaldehyde immediately after irradiation of the sample. Using this procedure changes of melting profiles of DNA from Escherichia coli B/r were demonstrated. (author)

  14. Effect of gamma irradiation on viability and DNA of Staphylococcus epidermidis and Escherichia coli.

    Science.gov (United States)

    Trampuz, Andrej; Piper, Kerryl E; Steckelberg, James M; Patel, Robin

    2006-09-01

    Gamma irradiation is widely used for sterilization; however, its effect on elimination of amplifiable DNA, an issue of relevance to molecular diagnostic approaches, has not been well studied. The effect of gamma irradiation on the viability of Staphylococcus epidermidis and Escherichia coli (using quantitative cultures) and on their DNA (using quantitative 16S rRNA gene PCR) was evaluated. Viability was abrogated at 2.8 and 3.6 kGy for S. epidermidis and E. coli, respectively. The radiation dose required to reduce viable bacteria by one log10 (D10 value) was 0.31 and 0.35 kGy for S. epidermidis and E. coli, respectively. D10 values for amplifiable DNA extracted from bacteria were 2.58 and 3.09 kGy for S. epidermidis and E. coli, respectively, whereas D10 values for amplifiable DNA were significantly higher for DNA extracted from irradiated viable bacterial cells (22.9 and 52.6 kGy for S. epidermidis and E. coli, respectively; Pgamma irradiation of DNA in viable bacterial cells has little effect on amplifiable DNA, was not able to eliminate amplifiable 16S rRNA genes at a dose of up to 12 kGy and cannot therefore be used for elimination of DNA contamination of PCR reaction components or laboratory equipment when this DNA is present in microbial cells. This finding has practical implications for those using molecular diagnostic techniques in microbiology.

  15. Nature of defects produced on thymine fragment by gamma irradiation of DNA

    International Nuclear Information System (INIS)

    Teoule, R.; Bonicel, A.

    1975-01-01

    A study is reported of the nature of the DNA thymine fragment damage induced by gamma radiation in vitro conditions, by a new method involving hydrolysis in mild conditions. It is highly probable that the main lesions observed in vitro on the DNA polynucleotide chain, namely thymine glycol, 5,6-dihydroxy-5,6-dihydrothymine and 1'-(N-formamidol) deoxyribose, are formed in vivo conditions

  16. Specitic gene alterations in radiation-induced tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Joo Mee; Kang, Chang Mo; Lee, Seung Sook; Cho, Chul Koo; Bae, Sang Woo; Lee, Su Jae; Lee, Yun Sil [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2004-07-01

    To identify a set of genes involved in the development of radiation-induced tumorigenesis, we used DNA microarrays consisting of 1,176 mouse genes and compared expression profiles of radioresistant cells, designated NIH3T3-R1 and -R4. These cells were tumorigenic in a nude mouse grafting system, as compared to the parental NIH3T3 cells. Expressions of MDM2, CDK6 and CDC25B were found to increase more than 3-fold. Entactin protein levels were downregulated in NIH3T3-R1 and -R4 cells. Changes in expression genes were confirmed by reverse transcription-PCR or western blotting. When these genes were transfected to NIH3T3 cells, the CDC25B and MDM2 overexpressing NIH3T3 cells showed radioresistance, while 2 CDK6 overexpressing cells did not. In the case of entactin overexpressing NIH3T3-R1 or R-4 cells were still radioresistant. Furthermore, the CDC25B and MDM2 overexpressing cells grafted to nude mice, were tumorigenic. NIH3T3-R1 and R4 cells showed increased radiation-induced apoptosis, accompanied by faster growth rate, rather than and earlier radiation-induced G2/M phase arrest, suggesting that the radioresistance of NIH3T3-R1 and R4 cells was due to faster growth rate, rather than induction of apoptosis. In the case of MDM2 and CDC25B overexpressing cells, similar phenomena, such as increased apoptosis and faster growth rate, were shown. The above results, therefore, demonstrate involvement of CDC25B and MDM2 overexpression in radiation-induced tumorigenesis and provide novel targets for detection of radiation-induced carcinogenesis.

  17. Localized Cerebral Energy Failure in DNA Polymerase Gamma-Associated Encephalopathy Syndromes

    Science.gov (United States)

    Tzoulis, Charalampos; Neckelmann, Gesche; Mork, Sverre J.; Engelsen, Bernt E.; Viscomi, Carlo; Moen, Gunnar; Ersland, Lars; Zeviani, Massimo; Bindoff, Laurence A.

    2010-01-01

    Mutations in the catalytic subunit of the mitochondrial DNA-polymerase gamma cause a wide spectrum of clinical disease ranging from infantile hepato-encephalopathy to juvenile/adult-onset spinocerebellar ataxia and late onset progressive external ophthalmoplegia. Several of these syndromes are associated with an encephalopathy that…

  18. Persistent DNA damage after high dose in vivo gamma exposure of minipig skin.

    Directory of Open Access Journals (Sweden)

    Emad A Ahmed

    Full Text Available Exposure to high doses of ionizing radiation (IR can lead to localized radiation injury of the skin and exposed cells suffer dsDNA breaks that may elicit cell death or stochastic changes. Little is known about the DNA damage response after high-dose exposure of the skin. Here, we investigate the cellular and DNA damage response in acutely irradiated minipig skin.IR-induced DNA damage, repair and cellular survival were studied in 15 cm(2 of minipig skin exposed in vivo to ~50 Co-60 γ rays. Skin biopsies of control and 4 h up to 96 days post exposure were investigated for radiation-induced foci (RIF formation using γ-H2AX, 53BP1, and active ATM-p immunofluorescence. High-dose IR induced massive γ-H2AX phosphorylation and high 53BP1 RIF numbers 4 h, 20 h after IR. As time progressed RIF numbers dropped to a low of 3-fold elevated at all subsequent time points. Replicating basal cells (Ki67+ were reduced 3 days post IR followed by increased proliferation and recovery of epidermal cellularity after 28 days.Acute high dose irradiation of minipig epidermis impaired stem cell replication and induced elevated apoptosis from 3 days onward. DNA repair cleared the high numbers of DBSs in skin cells, while RIFs that persisted in <1% cells marked complex and potentially lethal DNA damage up to several weeks after exposure. An elevated frequency of keratinocytes with persistent RIFs may thus serve as indicator of previous acute radiation exposure, which may be useful in the follow up of nuclear or radiological accident scenarios.

  19. Expression of endothelial nitric oxide synthase in acute radiation-induced cerebral edema

    International Nuclear Information System (INIS)

    Liu Baoguo; Zhang Baomin; Chen Xiaohua; Gao Yabing; Wang Dewen

    2000-01-01

    Objective: To study the relation between changes in expression of endothelial nitric oxide synthase (eNOS) in brain vascular endothelial cells and acute radiation-induced cerebral edema after 60 Co gamma knife irradiation with a high dose. Methods: The right caudate nucleus of rats were irradiated with 200 Gy 60 Co gamma knife. the rats were sacrificed within 14 days after irradiation. By a light microscopy, electron microscopy, immunohistochemistry and in situ hybridization, the authors studied the formation and development of acute radiation-induced cerebral edema as well as the expression of eNOS in brain vascular endothelial cells. Results: Acute radiation-induced cerebral edema was observed morphologically 2 hours after irradiation and peaked on day 3 after irradiation. The expression of eNOS in brain vascular endothelial cells markedly increased 2 hours after irradiation, which could be consistently visualized during the acute developmental phase of radiation-induced cerebral edema. Conclusion: The increased expression of eNOS may be related to the formation and development of acute radiation-induced cerebral edema after 60 Co gamma knife irradiation with a high dose

  20. Radiation induced degradation of some crystalline amino acids

    International Nuclear Information System (INIS)

    Gejvall, T.; Loefroth, G.

    1975-01-01

    The gamma-radiation induced degradation of five crystalline DL-amino acids, leucine, isoleucine, norleucine, valine, and norvaline, has been quantitatively studied. The major products are carboxylic acids formed by deamination of the amino acids, ammonia, amines formed by decarboxylation of the amino acids, and carbon dioxide. In addition, carbonyl compounds and amides, plus small amounts of hydrogen gas and various hydrocarbons have been detected. The total degradation, (-M), has been determined (by isotope dilution) to be 8 for valine and 14 for leucine. (author)

  1. Use of radiation-induced polymers in cement slurries

    International Nuclear Information System (INIS)

    Knight, B.L.; Rhudy, J.S.; Gogarty, W.B.

    1976-01-01

    Water loss from cement slurries is reduced by incorporating within a cement slurry a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in 10-60 percent aqueous monomer solution with gamma radiation. The aqueous monomer solution preferably contains 25-99 percent acrylamide and 75-1 percent sodium acrylate. The polymer can be present in concentration of about 0.001 to about 3.0 weight percent, based on the aqueous phase of the slurry

  2. Protection against radiation-induced performance decrement in mice

    International Nuclear Information System (INIS)

    Mukherjee, S.K.; Pant, Kanchan; Goel, H.C.; Jain, Viney

    1997-01-01

    Recognizing that there is lack of information on the effects of low-level ionizing radiations and the modifying role of radioprotectors, an attempt has been made in this study to explore the relationship between impairment of spatial learning and low level of radiation exposure. A radial arm maze was utilised to evaluate radiation-induced behavioural alterations and performance decrement in mice. Immediately after whole body exposure to gamma radiation (absorbed dose, 1 Gy) significant perturbations in the learned behaviour of the animals were observed. The regular control movement became irregular and the food consumption time was reduced appreciably (40%). Recovery took place in four days. If diltiazem (7 mg/kg b.w.), a Ca 2+ channel blocker and a radioprotector, was administered i.p. 20-30 min prior to irradiation, radiation-induced behavioural abnormalities were reduced. Mechanisms underlying protection by diltiazem against radiation-induced performance decrement observed in the present study need to be investigated. (author). 23 refs., 2 figs

  3. DNA repair in mammalian nerve cells. 1. DNA synthesis in cerebral cortex induced by γ-irradiation of rats

    International Nuclear Information System (INIS)

    Ivanov, V.A.; Terpilovskaya, O.N.; Kulikov, A.V.; Tret'yak, T.M.

    1987-01-01

    A study was made of the DNA synthesis in cerebral cortex of rats, aged 14 and 60 days, after gamma-irradiation in vivo in a dose of 7 Gy, the 3 H-thymidine incorporation into DNA being determined. 137 Cs-radiation induces additional DNA synthesis in the neocortex tissue and in neurons. In the cortex of 14 day-old rats, the induced DNA synthesis stops 2 hours after irradiation, whereas in the cortex of 60 day-old rats and in neurons of rats of both the age groups DNA synthesis is proceeding for 3-35 hours. Specificity of DNA reparation, processes in nondividing cells is discussed

  4. Radiation-induced parotid cancer

    International Nuclear Information System (INIS)

    Walker, M.J.; Chaudhuri, P.K.; Wood, D.C.; Das Gupta, T.K.

    1981-01-01

    A retrospective analysis of 72 cases of primary malignant tumors of the parotid gland treated at the University of Illinois Hospital, Chicago, from 1950 through 1978 revealed that six of these had developed from two to 24 years after irradiation of the head or neck for various benign and malignant neoplastic conditions. At the time of irradiation, ages ranged from 7 to 73 years; the sex distribution was equal. From our findings and those in 26 cases reported by various other authors, the following criteria are proposed for the designation of a parotid tumor as being radiation induced: (1) well-documented radiation exposure; (2) part of irradiation must incorporate the gland in which the cancer subseqently arises; (3) exposure to a minimum of 300 rads; and (4) minimum latent period of two years. In view of the widespread use in the past of heat and neck irradiation of benign neoplastic disease, the surgeon should be aware of this possible link with parotid gland tumor

  5. Ubiquitin-dependent system controls radiation induced apoptosis

    International Nuclear Information System (INIS)

    Delic, J.; Magdelenat, H.; Glaisner, S.; Magdelenat, H.; Maciorowski, Z.

    1997-01-01

    The selective proteolytic pathway, dependent upon 'N-end rule' protein recognition/ubiquitination and on the subsequent proteasome dependent processing of ubiquitin conjugates, operates in apoptosis induced by γ-irradiation. The proteasome inhibitor peptide aldehyde, MG132, efficiently induced apoptosis and was also able (at doses lower than those required for apoptosis induction) to potentiate apoptosis induced by DNA damage. Its specificity is suggested by the induction of the ubiquitin (UbB and UbC) and E1 (ubiquitin activating enzyme) genes and by an altered ubiquitination pattern. More selectively, a di-peptide competitor of the 'N-end rule' of ubiquitin dependent protein processing inhibited radiation induced apoptosis. This inhibition is also followed by an altered ubiquitination pattern and by activation of Poly (ADP-ribose) polymerase (PARP). These data strongly suggest that early apoptosis radiation induced events are controlled by ubiquitin-dependent proteolytic processing. (author)

  6. Mint oil (Mentha spicata Linn.) offers behavioral radioprotection: a radiation-induced conditioned taste aversion study.

    Science.gov (United States)

    Haksar, A; Sharma, A; Chawla, R; Kumar, Raj; Lahiri, S S; Islam, F; Arora, M P; Sharma, R K; Tripathi, R P; Arora, Rajesh

    2009-02-01

    Mentha spicata Linn. (mint), a herb well known for its gastroprotective properties in the traditional system of medicine has been shown to protect against radiation-induced lethality, and recently its constituents have been found to possess calcium channel antagonizing properties. The present study examined the behavioral radioprotective efficacy of mint oil (obtained from Mentha spicata), particularly in mitigating radiation-induced conditioned taste aversion (CTA), which has been proposed as a behavioral endpoint that is mediated by the toxic effects of gamma radiation on peripheral systems, primarily the gastrointestinal system in the Sprague-Dawley rat model. Intraperitoneal administration of Mentha spicata oil 10% (v/v), 1 h before 2 Gy gamma radiation, was found to render significant radioprotection against CTA (p Mentha spicata can be effectively utilized in preventing radiation-induced behavioral changes. Copyright (c) 2008 John Wiley & Sons, Ltd.

  7. Radiation-induced instability of human genome

    International Nuclear Information System (INIS)

    Ryabchenko, N.N.; Demina, Eh.A.

    2014-01-01

    A brief review is dedicated to the phenomenon of radiation-induced genomic instability where the increased level of genomic changes in the offspring of irradiated cells is characteristic. Particular attention is paid to the problems of genomic instability induced by the low-dose radiation, role of the bystander effect in formation of radiation-induced instability, and its relationship with individual radiosensitivity. We believe that in accordance with the paradigm of modern radiobiology the increased human individual radiosensitivity can be formed due to the genome instability onset and is a significant risk factor for radiation-induced cancer

  8. Radiation-Induced Liver Toxicity.

    Science.gov (United States)

    Munoz-Schuffenegger, Pablo; Ng, Sylvia; Dawson, Laura A

    2017-10-01

    The advent of highly conformal radiation therapy (RT) has defined a new role for RT in the treatment of both primary and metastatic liver cancer. Despite major advances in how RT is delivered, radiation-induced liver disease (RILD) remains a concern. Classic RILD, characterized by anicteric ascites and hepatomegaly, is unlikely to occur if treating to doses of ≤30Gy in 2Gy per fraction in patients with baseline Child-Pugh A liver function. On the other hand, nonclassic RILD is a spectrum of liver toxicity, including a general decline in liver function and elevation of liver enzymes. It is less well defined and less predictable, especially in patients with underlying liver disease. Scoring and quantifying RILD remains a challenge. The Child-Pugh score has been the most consistently used parameter. Other scoring systems such as the albumin-bilirubin score provide further discrimination in patients with hepatocellular carcinoma, although their value in patients treated with RT remains to be established. Many serum and imaging biomarkers of liver function are currently being investigated, and they will provide further useful information in the future for local and global liver function assessment, for planning optimization, and for treatment adaptation. To date, no pharmacological therapies have provided consistent results in mitigating RILD once it has manifested clinically. Numerous promising treatment strategies including TGFβ inhibition, Hedgehog inhibition, CXCR4 inhibition, hepatocyte transplantation, and bone marrow-derived stromal cell therapy, have potential to be helpful in the treatment of RILD in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Using Rouse-Fowler model to describe radiation-induced electrical conductivity of nanocomposite materials

    Science.gov (United States)

    Dyuryagina, N. S.; Yalovets, A. P.

    2017-05-01

    Using the Rouse-Fowler (RF) model this work studies the radiation-induced electrical conductivity of a polymer nanocomposite material with spherical nanoparticles against the intensity and exposure time of gamma-ray, concentration and size of nanoparticles. The research has found the energy distribution of localized statesinduced by nanoparticles. The studies were conducted on polymethylmethacrylate (PMMA) with CdS nanoparticles.

  10. Visible light- and radiation-induced alkylation of pyridine ring with alkanoic acid

    International Nuclear Information System (INIS)

    Sugimori, Akira; Yamada, Tetsuo

    1986-01-01

    Quinoline and 4-methylquinoline are efficiently alkylated with alkanoic acid in the presence of iron(III) sulfate upon visible light-irradiation. Iron(III) sulfate not only accelerates the photoreaction but also increases the yield of alkylation. Gamma-irradiation also brings about the alkylation. In the photo- and radiation-induced alkylation with alkanoic acid, alkyl radicals play important roles. (author)

  11. Radiation-induced carcinoma of the penis

    International Nuclear Information System (INIS)

    Wells, A.D.; Pryor, J.P.

    1986-01-01

    Two patients with carcinoma of the penis were treated with interstitial radiation. They were cured of their disease for 17 and 21 years respectively and then developed radiation-induced tumours. (author)

  12. Radiation-Induced Vaccination to Breast Cancer

    Science.gov (United States)

    2015-10-01

    Award Number: W81XWH-11-1-0531 TITLE: Radiation-Induced Vaccination to Breast Cancer PRINCIPAL INVESTIGATOR: William H. McBride CONTRACTING...FORM TO THE ABOVE ADDRESS. 1. REPORT DATE 2. REPORT TYPE Annual 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Radiation-Induced Vaccination to...determine abscopal responses that are hypothesized to be due to RT- induced vaccination . RT was started 10 days after the first and 3rd dose of

  13. Radiation Induced Vaccination to Breast Cancer

    Science.gov (United States)

    2016-12-01

    Award Number: W81XWH-11-1-0531 TITLE: Radiation-Induced Vaccination to Breast Cancer PRINCIPAL INVESTIGATOR: William H. McBride CONTRACTING...TITLE AND SUBTITLE Radiation-Induced Vaccination to Breast Cancer 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0531 5c. PROGRAM ELEMENT NUMBER 6...therapy to generate an in situ tumor vaccine and abscopal effects at distant tumor sites (13), giving some rationale for this attempt to examine this

  14. Autoradiographic study of gamma-ray induced unscheduled DNA synthesis in bean root meristem cells

    International Nuclear Information System (INIS)

    Liu Zhenshen; Qiu Quanfa; Chen Dongli

    1989-01-01

    The gamma-ray induced unscheduled DNA synthesis in root meristem cells of Vica faba was studied autoradiographically by calculating the number of cells with different 3H-thymidine labelling degree. It was found that the level of unscheduled synthesis in cells with intermediate dose (500 R) irradiation was higher than that in cells with lower dose (250 R) irradiation; however, higher dose (1000 R) irradiation would inhibit the reparative replication

  15. An unusual DNA sequence observed in the. gamma. globin gene loci of two members of a Chinese family

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Q.C.

    1989-01-01

    There are two nonallelic human {gamma} globin genes located on the short arm of chromosome No. 11 in the order 5{prime}-{sup G}{sub {gamma}}-{sup A}{sub {gamma}}-3{prime}. Various modifications of the two {gamma} genes have been reported and include: deletions, triplications, quadruplications and recently a quintuplication. These are generally created by one or more unequal crossovers in the {gamma} globin gene regions on adjacent chromosomes. During the course of looking for a {gamma}{sup {degree}} thalassemia, which might be due to a crossover of looking for a {gamma} genes, two cases were found in the family W. Bgl II mapping studies showed a 5 kb deletion at the {gamma} gene loci in these individuals. The Bgl II fragment from the {gamma} gene loci of R.W. was cloned into the phage vector QR1. Phage mapping showed that two out of the three Pst I sites within the Bgl II fragment were missing which suggested that the crossover might have occurred within the {gamma} gene, possibly within the {gamma}IVS II region. Sequence analysis of the cloned fragment revealed an unusual sequence which had no sequence homology with the {gamma} gene region except for a small 264 bp region near the 3{prime} end. The orientation of the 264 bp fragment is inverted relative to homologous sequences in the {sup G}{sub {gamma}} and {sup A}{sub {gamma}} IVS II. The unusual sequence was computer analyzed for homology with every DNA sequence file in the EMBL database and GenBank and did not show any significant homologies to all the available DNA sequences except for the 264 bp {gamma}IVS II homology.

  16. Potent radio-protective effects of vitamins E and C on radiation induced DNA damage in gametes leading to lower frequencies of chromosomal aberrations and micronuclei in subsequent embryos

    International Nuclear Information System (INIS)

    Hossein Mozdarani

    2007-01-01

    Complete text of publication follows. Objective: To compare the effects of parental and maternal exposure of NMRI mice with γ-rays on gametes in the absence or presence of vitamins E and C and subsequent cytogenetic damage in pre-implantation embryos generated from irradiated gametes. Materials and Methods: Male and female NMRI mice were whole body irradiated in the presence of 200 IU/Kg vitamin E and 100 μg/ml vitamin C. Various mating schemes were designed for mating of irradiated mice, e.g. mating irradiated male with non-irradiated female, irradiated female with non irradiated male or both male and female irradiated. About 68 h post coitus, 4-8-cell embryos were flushed out from oviducts and fixed on slides using standard methods in order to screen for chromosome abnormalities and micronuclei. Results: In control embryos, frequencies of abnormal metaphase and embryos with micronuclei was low and there was no significant difference between vitamins treated samples and controls. However there was an increase in both abnormal metaphases and micronuclei frequency in embryos generated after parental or maternal irradiation or both. Vitamin E effectively reduced the frequency of aneuploidy in all irradiated groups and vitamin C was very effective in reducing the frequencies of micronuclei. DRF calculated for both vitamins indicate that vitamin C is more potent than vitamin E in reducing clastogenic effects of gamma-rays in pre-implantation embryos. Conclusion: Data indicate that γ-irradiation affects spermatogenesis and preovulatory stage oocytes in male and female mice respectively. These effects might be due to DNA alterations in sperms and oocytes affecting meiotic segregations that may lead to chromosome abnormalities in subsequent embryos expressed as numerical chromosome abnormalities or micronuclei. Administration of vitamins E and C before irradiation effectively reduced the frequency of chromosomal abnormalities. The way these vitamins reduces genotoxic

  17. Epigenetic changes of Arabidopsis genome associated with altered DNA methyltransferase and demethylase expressions after gamma irradiation

    International Nuclear Information System (INIS)

    Kim, Ji Eun; Cho, Eun Ju; Kim, Ji Hong; Chung, Byung Yeoup; Kim, Jin Hong

    2012-01-01

    DNA methylation at carbon 5 of cytosines is a hall mark of epigenetic inactivation and heterochromatin in both plants and mammals. In Arabidopsis, DNA methylation has two roles that protect the genome from selfish DNA elements and regulate gene expression. Plant genome has three types of DNA methyltransferase, METHYLTRANSFERASE 1 (MET1), DOMAINREARRANGED METHYLASE (DRM) and CHROMOMETHYLASE 3 (CMT3) that are capable of methylating CG, CHG (where H is A, T, or C) and CHH sites, respectively. MET1 is a maintenance DNA methyltransferase that controls CG methylation. Two members of the DRM family, DRM1 and DRM2, are responsible for de novo methylation of CG, CHG, and CHH sites but show a preference for CHH sites. Finally, CMT3 principally carries out CHG methylation and is involved in both de novo methylation and maintenance. Alternatively, active DNA demethylation may occur through the glycosylase activity by removing the methylcytosines from DNA. It may have essential roles in preventing transcriptional silencing of transgenes and endogenous genes and in activating the expression of imprinted genes. DNA demetylation in Arabidopsis is mediated by the DEMETER (DME) family of bifunctional DNA glycosylase. Three targets of DME are MEA (MEDEA), FWA (FLOWERING WAGENINGEN), and FIS2 (FERTILIZATION INDEPENDENT SEED 2). The DME family contains DEMETER-LIKE 2 (DML2), DML3, and REPRESSOR OF SILENING 1 (ROS1). DNA demetylation by ROS1, DML2, and DML3 protect the hypermethylation of specific genome loci. ROS1 is necessary to suppress the promoter methylation and the silencing of endogenous genes. In contrast, the function of DML2 and DML3 has not been reported. Several recent studies have suggested that epigenetic alterations such as change in DNA methylation and histone modification should be caused in plant genomes upon exposure to ionizing radiation. However, there is a lack of data exploring the underlying mechanisms. Therefore, the present study aims to characterize and

  18. Epigenetic changes of Arabidopsis genome associated with altered DNA methyltransferase and demethylase expressions after gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Eun; Cho, Eun Ju; Kim, Ji Hong; Chung, Byung Yeoup; Kim, Jin Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    DNA methylation at carbon 5 of cytosines is a hall mark of epigenetic inactivation and heterochromatin in both plants and mammals. In Arabidopsis, DNA methylation has two roles that protect the genome from selfish DNA elements and regulate gene expression. Plant genome has three types of DNA methyltransferase, METHYLTRANSFERASE 1 (MET1), DOMAINREARRANGED METHYLASE (DRM) and CHROMOMETHYLASE 3 (CMT3) that are capable of methylating CG, CHG (where H is A, T, or C) and CHH sites, respectively. MET1 is a maintenance DNA methyltransferase that controls CG methylation. Two members of the DRM family, DRM1 and DRM2, are responsible for de novo methylation of CG, CHG, and CHH sites but show a preference for CHH sites. Finally, CMT3 principally carries out CHG methylation and is involved in both de novo methylation and maintenance. Alternatively, active DNA demethylation may occur through the glycosylase activity by removing the methylcytosines from DNA. It may have essential roles in preventing transcriptional silencing of transgenes and endogenous genes and in activating the expression of imprinted genes. DNA demetylation in Arabidopsis is mediated by the DEMETER (DME) family of bifunctional DNA glycosylase. Three targets of DME are MEA (MEDEA), FWA (FLOWERING WAGENINGEN), and FIS2 (FERTILIZATION INDEPENDENT SEED 2). The DME family contains DEMETER-LIKE 2 (DML2), DML3, and REPRESSOR OF SILENING 1 (ROS1). DNA demetylation by ROS1, DML2, and DML3 protect the hypermethylation of specific genome loci. ROS1 is necessary to suppress the promoter methylation and the silencing of endogenous genes. In contrast, the function of DML2 and DML3 has not been reported. Several recent studies have suggested that epigenetic alterations such as change in DNA methylation and histone modification should be caused in plant genomes upon exposure to ionizing radiation. However, there is a lack of data exploring the underlying mechanisms. Therefore, the present study aims to characterize and

  19. Radiation-induced neurobehavioral dysfunctions

    International Nuclear Information System (INIS)

    Manda, Kailash

    2013-01-01

    There is a lacuna between sparsely reported immediate effects and the well documented delayed effects on cognitive functions seen after ionizing radiation exposure. We reported the radiation-dose dependent incongruity in the early cognitive changes and its correlation with the structural aberration as reported by imaging study. The delayed effect of radiation was investigated to understand the role of hippocampal neurogenesis in the functional recovery of cognition. C57BL/6 mice were exposed to different doses of γ-radiation and 24 hrs after exposure, the stress and anxiety levels were examined in the Open Field Exploratory Paradigms (OFT). 48hrs after irradiation, the hippocampal dependent recognition memory was observed by the Novel Object Recognition Test (NORT) and the cognitive function related to memory processing and recall was tested using the Elevated Plus Maze (EPM). Visualization of damage to the brain was done by diffusion tensor imaging at 48 hours post-irradiation. Results indicate a complex dose independent effect on the cognitive functions immediately after exposure to gamma rays. Radiation exposure caused short term memory dysfunctions at lower doses which were seen to be abrogated at higher doses, but the long term memory processing was disrupted at higher doses. The Hippocampus emerged as one of the sensitive regions to be affected by whole body exposure to gamma rays, which led to profound immediate alterations in cognitive functions. Furthermore, the results indicate a cognitive recovery process, which might be dependent on the extent of damage to the hippocampal region. While evaluating the delayed effect of radiation on the hippocampal neurogenesis, we observed that higher doses groups showed comparatively more adaptive regenerative neurogenic potential which they could not sustain at later stages. Our studies reported an important hitherto uncovered phenomenon of neurobehavioral dysfunctions in relation to radiation dose. Nevertheless, a

  20. Assessment of gamma ray-induced DNA damage in Lasioderma serricorne using the comet assay

    International Nuclear Information System (INIS)

    Kameya, Hiromi; Miyanoshita, Akihiro; Imamura, Taro; Todoriki, Setsuko

    2012-01-01

    We attempted a DNA comet assay under alkaline conditions to verify the irradiation treatment of pests. Lasioderma serricorne (Fabricius) were chosen as test insects and irradiated with gamma rays from a 60 Co source at 1 kGy. We conducted the comet assay immediately after irradiation and over time for 7 day. Severe DNA fragmentation in L. serricorne cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. The parameters of the comet image analysis were calculated, and the degree of DNA damage and repair were evaluated. Values for the Ratio (a percentage determined by fluorescence in the damaged area to overall luminance, including intact DNA and the damaged area of a comet image) of individual cells showed that no cells in the irradiated group were included in the Ratio<0.1 category, the lowest grade. This finding was observed consistently throughout the 7-day post-irradiation period. We suggest that the Ratio values of individual cells can be used as an index of irradiation history and conclude that the DNA comet assay under alkaline conditions, combined with comet image analysis, can be used to identify irradiation history. - Highlights: ► We investigated the DNA comet assay to verify the irradiation of pests. ► Ratio and Tail Moment were higher in irradiated groups than in the control group. ► The DNA comet assay can be used to identify irradiation history.

  1. Thermus thermophilis dnaX homolog encoding gamma- and tau-like proteins of the chromosomal replicase.

    Science.gov (United States)

    Yurieva, O; Skangalis, M; Kuriyan, J; O'Donnell, M

    1997-10-24

    This report identifies the dnaX homolog from Thermus thermophilis. Replicases from bacteria to humans contain subunits that are homologous to one another. These homologs are subunits of a clamp loading apparatus that loads sliding clamps onto DNA, which in turn act as mobile tethers for the replication machinery. In Escherichia coli, two of these subunits (gamma and tau) are encoded by one gene (dnaX) in nearly equal amounts by way of an efficient translational frameshift. The gamma and tau subunits form the central touchpoint that holds together two DNA polymerases with one clamp loading apparatus to form the E. coli chromosomal replicase, DNA polymerase III holoenzyme. The E. coli holoenzyme is an efficient replication machine that simultaneously replicates both strands of duplex DNA. The T. thermophilis dnaX homolog also contains a frameshift signature and produces both tau- and gamma-like proteins. Recombinant T. thermophilis tau- and gamma-like proteins, expressed in E. coli, have an oligomeric state similar to that of their E. coli counterparts and display ATPase activity that is stimulated by DNA. These results imply that T. thermophilis utilizes a DNA polymerase III holoenzyme replication machinery similar to that of E. coli.

  2. Mechanism of Hydrophilicity by Radiation-Induced Surface Activation

    Science.gov (United States)

    Honjo, Yoshio; Furuya, Masahiro; Takamasa, Tomoji; Okamoto, Koji

    When a metal oxide is irradiated by gamma rays, the irradiated surface becomes hydrophilic. This surface phenomenon is called as radiation-induced surface activation (RISA) hydrophilicity. In order to investigate gamma ray-induced and photoinduced hydrophilicity, the contact angles of water droplets on a titanium dioxide surface were measured in terms of irradiation intensity and time for gamma rays of cobalt-60 and for ultraviolet rays. Reciprocals of the contact angles increased in proportion to the irradiation time before the contact angles reached its super-hydrophilic state. The irradiation time dependency is equal to each other qualitatively. In addition, an effect of ambient gas was investigated. In pure argon gas, the contact angle remains the same against the irradiation time. This clearly indicates that certain humidity is required in ambient gas to take place of RISA hydrophilicity. A single crystal titanium dioxide (100) surface was analyzed by X-ray photoelectron spectrometry (XPS). After irradiation with gamma rays, a peak was found in the O1s spectrum, which indicates the adsorption of dissociative water to a surface 5-fold coordinate titanium site, and the formation of a surface hydroxyl group. We conclude that the RISA hydrophilicity is caused by chemisorption of the hydroxyl group on the surface.

  3. Defense mechanisms against radiation induced teratogenic damage in mice

    International Nuclear Information System (INIS)

    Kato, F.; Ootsuyama, A.; Nomoto, S.; Norimura, T.

    2002-01-01

    Experimental studies with mice have established that fetuses at midgestational stage are highly susceptible to malformation at high, but not low, doses of radiation. When DNA damage is produced by a small amount of radiation, it is efficiently eliminated by DNA repair. However, DNA repair is not perfect. There must be defense mechanisms other than DNA repair. In order to elucidate the essential role of p53 gene in apoptotic tissue repair, we compared the incidence of radiation-induced malformations and deaths (deaths after day 10) in wild-type p53 (+/+) mice and null p53 (-/-) mice. For p53 (+/+) mice, an X-ray dose of 2 Gy given at a high dose-rate (450 mGy/min) to fetuses at 9.5 days of gestation was highly lethal and considerably teratogenic whereas it was only slightly lethal but highly teratogenic for p53 (-/-) fetuses. This reciprocal relationship of radiosensitivity to malformations and deaths supports the notion that fetal tissues have a p53 -dependent idguardianln of the tissue that aborts cells bearing radiation-induced teratogenic DNA damage. When an equal dose of 2 Gy given at a 400-fold lower dose-rate (1.2 mGy/min), this dose became not teratogenic for p53 (+/+) fetuses exhibiting p53 -dependent apoptosis, whereas this dose remained teratogenic for p53 (-/-) fetuses unable to carry out apoptosis. Furthermore, when the dose was divided into two equal dose fractions (1+1 Gy) at high dose rate, separated by 24 hours, the incidences of malformations were equal with control level for p53 (+/+), but higher for p53 (-/-) mice. Hence, complete elimination of teratogenic damage from irradiated tissues requires a concerted cooperation of two mechanisms; proficient DNA repair and p53-dependent apoptotic tissue repair

  4. Radiation-induced apoptosis in different pH environments in vitro

    International Nuclear Information System (INIS)

    Lee, Hyung-Sik; Park, Heon J.; Lyons, John C.; Griffin, Robert J.; Auger, Elizabeth A.; Song, Chang W.

    1997-01-01

    Purpose: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Methods and Materials: Mammary adenocarcinoma cells of A/J mice (SCK cells) were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 deg. C for 24-120 h the extent of apoptosis was determined using agarose gel electrophoresis, TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The clonogenicity of the cells irradiated in different pH medium was determined, and the progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in SCK cells in pH 7.5 medium within 48 h as judged from the results of four different assays mentioned. Radiation-induced apoptosis declined as the medium pH was lowered from 7.5 to 6.4. Specifically, the radiation-induced degradation of DNA including the early DNA breaks, as determined with the TUNEL method, progressively declined as the medium pH was lowered so that little DNA fragmentation occurred 48 h after irradiation with 12 Gy in pH 6.6 medium. When the cells were irradiated and incubated for 48 h in pH 6.6 medium and the medium was replaced with pH 7.5 medium, DNA fragmentation promptly occurred. DNA fragmentation also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 h or longer post-irradiation before incubation in pH 6.6 medium. The radiation-induced G 2 arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Conclusion: Radiation-induced apoptosis in SCK cells in vitro is reversibly suppressed in an acidic environment. Taking the results of four different assays together, it was concluded that early step(s) in the apoptotic pathway, probably the DNA break or upstream of DNA break, is

  5. Amelioration of ionizing radiation induced lipid peroxidation in mouse liver by Moringa oleifera Lam. leaf extract

    International Nuclear Information System (INIS)

    Sinha, Mahuya; Das, Dipesh Kr; Dey, Sanjit; Datta, Sanjukta; Ghosh, Santinath

    2012-01-01

    Protective effect of Moringa oleifera leaf extract (MoLE) against radiation-induced lipid peroxidation has been investigated. Swiss albino mice, selected from an inbred colony, were administered with MoLE (300 mg/kg body wt) for 15 days before exposing to a single dose of 5 Gy 60 Co-gamma radiation. After treatments, animals were necropsied at different post irradiation intervals (days 1, 7 and 15) and hepatic lipid peroxidation and reduced glutathione (GSH) contents were estimated to observe the relative changes due to irradiation and its possible amelioration by MoLE. It was observed that, MoLE treatment restored GSH in liver and prevented radiation induced augmentation in hepatic lipid peroxidation. Phytochemical analysis showed that MoLE possess various phytochemicals such as ascorbic acid, phenolics (catechin, epicatechin, ferulic acid, ellagic acid, myricetin) etc., which may play the key role in prevention of hepatic lipid peroxidation by scavenging radiation induced free radicals. (author)

  6. Radiation-induced grafting of styrene on polypropylene pellets

    International Nuclear Information System (INIS)

    Souza, Camila P.; Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

    2009-01-01

    The changes of radiation-induced in polypropylene (PP) pellets exposed to gamma irradiation in inert atmosphere were investigated in correlation with the applied doses (10 and 50 kGy). Also, results from the grafting of styrene onto PP pellets using simultaneous irradiation at the same doses are presented. The grafting reaction was carried out using toluene as solvent, under nitrogen atmosphere and at room temperature. The properties of the irradiated and grafted PP pellets were studied using Melt Flow Index, thermal analysis (TG and DSC), and ATR-IR. The degree of grafting (DOG) for the grafted pellets was gravimetrically determined. The results showed that radiation-induced graft polymerization on pellets were successfully obtained and the influence of dose irradiated did not change the thermal properties in spite of the increase in the MFI and consequently this increase in the viscosity results an decrease the molecular mass. The MFI for grafted pellets was not achievable because the high degree of viscosity of polymer, even arising the test temperature, the polymer was not flow enough. (author)

  7. Depression of DNA synthesis rate following hyperthermia, gamma irradiation, cyclotron neutrons and mixed modalities

    International Nuclear Information System (INIS)

    Weber, H.J.; Muehlensiepen, H.; Porschen, W.; Feinendegen, L.E.; Dietzel, F.

    1978-01-01

    The incorporation of the thymidine analogue I-UdR is proportional to the activity of DNA synthesis. The maximum depression of 125-I-UdR incorporation occurs approximately 4 hours after all kinds of treatment. The increase which follow reflects cell processes like reoxygeneration, recovery, recycling and recruitment (although a direct relation is not yet demonstrable). The degree of depression 4 hours after treatment and the time required needs to reach control level is dependent on dose and radiation quaility but no such dependence could be clearly seen for the times of hyperthermia treatment we used. Neutron irradiation and the combination gamma irradiation + hyperthermia show a higher depression and a slower return to normal than gamma irradiation at the same dose. (orig.) [de

  8. Estimating DNA coverage and abundance in metagenomes using a gamma approximation

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Sean D; Dalevi, Daniel; Pati, Amrita; Mavromatis, Konstantinos; Ivanova, Natalia N; Kyrpides, Nikos C

    2010-01-01

    Shotgun sequencing generates large numbers of short DNA reads from either an isolated organism or, in the case of metagenomics projects, from the aggregate genome of a microbial community. These reads are then assembled based on overlapping sequences into larger, contiguous sequences (contigs). The feasibility of assembly and the coverage achieved (reads per nucleotide or distinct sequence of nucleotides) depend on several factors: the number of reads sequenced, the read length and the relative abundances of their source genomes in the microbial community. A low coverage suggests that most of the genomic DNA in the sample has not been sequenced, but it is often difficult to estimate either the extent of the uncaptured diversity or the amount of additional sequencing that would be most efficacious. In this work, we regard a metagenome as a population of DNA fragments (bins), each of which may be covered by one or more reads. We employ a gamma distribution to model this bin population due to its flexibility and ease of use. When a gamma approximation can be found that adequately fits the data, we may estimate the number of bins that were not sequenced and that could potentially be revealed by additional sequencing. We evaluated the performance of this model using simulated metagenomes and demonstrate its applicability on three recent metagenomic datasets.

  9. Modulation of Radiation Induced Toxicity by Caffeine Pre injection in Female Rats

    International Nuclear Information System (INIS)

    Ashry, O.M.

    2003-01-01

    The present work aims to evaluate the antioxidative role of caffeine (80 mg/kg b.w.). injected 1hour before exposure of female rats to a dose of (7 Gy) gamma irradiation. Haematological parameters, lipid peroxides, glutathione, AST and ALT were investigated 1, 3 and 7 days post irradiation and/or caffeine treatment. Exposure to ionizing radiation resulted in haematological disorders, elevated lipid peroxides, dropped glutathione levels and disturbed AST and ALT levels. Caffeine preinjection led to noticeable limitation of the drop in RBCs, Hb and Ht, improved MCV, MCHC, elevated glutathione, depressed lipid peroxide levels and moderated ALT level. Caffeine is an alkaloid (purine derivative) that contains flavonoids, which increases the antioxidative capacity of blood plasma (Hempel et al., 1999). It is an antioxidant that may help to protect against chemically-induced or radiation induced cancer in mice (Abraham, 1991 and Haung et al., 1997). Caffeine competes with oxygen for electrons and also scavenges hydroxyl radicals and reactive oxygen (Devasagayam and Kesavan, 1996). Contrary to previous investigations, conducted since 1960 reporting that caffeine potentiates DNA damage (Kihlman, 1977 and George et al., 1999) administered caffeine i.p. at a dose of 80 mg/kg body weight 1hour before irradiation of mice at 7.5 Gy. They described remarkable protection by caffeine resulting in the survival of 70% of mice at the end of 25 days and the number remained the same till 90 days

  10. Radiation induced genome instability: multiscale modelling and data analysis

    Science.gov (United States)

    Andreev, Sergey; Eidelman, Yuri

    2012-07-01

    Genome instability (GI) is thought to be an important step in cancer induction and progression. Radiation induced GI is usually defined as genome alterations in the progeny of irradiated cells. The aim of this report is to demonstrate an opportunity for integrative analysis of radiation induced GI on the basis of multiscale modelling. Integrative, systems level modelling is necessary to assess different pathways resulting in GI in which a variety of genetic and epigenetic processes are involved. The multilevel modelling includes the Monte Carlo based simulation of several key processes involved in GI: DNA double strand breaks (DSBs) generation in cells initially irradiated as well as in descendants of irradiated cells, damage transmission through mitosis. Taking the cell-cycle-dependent generation of DNA/chromosome breakage into account ensures an advantage in estimating the contribution of different DNA damage response pathways to GI, as to nonhomologous vs homologous recombination repair mechanisms, the role of DSBs at telomeres or interstitial chromosomal sites, etc. The preliminary estimates show that both telomeric and non-telomeric DSB interactions are involved in delayed effects of radiation although differentially for different cell types. The computational experiments provide the data on the wide spectrum of GI endpoints (dicentrics, micronuclei, nonclonal translocations, chromatid exchanges, chromosome fragments) similar to those obtained experimentally for various cell lines under various experimental conditions. The modelling based analysis of experimental data demonstrates that radiation induced GI may be viewed as processes of delayed DSB induction/interaction/transmission being a key for quantification of GI. On the other hand, this conclusion is not sufficient to understand GI as a whole because factors of DNA non-damaging origin can also induce GI. Additionally, new data on induced pluripotent stem cells reveal that GI is acquired in normal mature

  11. Radiation-induced linking reactions in polyethylene

    International Nuclear Information System (INIS)

    Zoepfl, F.J.

    1983-01-01

    Three types of measurements are reported relating to chemical reactions in polyethylene induced by ionizing radiation: 1) viscometric and low-angle laser light scattering measurements to determine the effect of a radical scavenger on the yield of links; 2) calorimetric measurements to determine the effect of radiation-induced linking on the melting behavior of polyethylene; and 3) high-resolution solution carbon 13 nuclear magnetic resonance (NMR) spectrometry measurements to determine the nature of the links and the method of their formation. The NMR results present the first direct detection of radiation-induced long-chain branching (Y links) in polyethylene, and place an apparent upper limit on the yield of H-shaped crosslinks that are formed when polyethylene is irradiated to low absorbed doses. The effect of radiation-induced linking on the melting behavior of polyethylene was examined using differential scanning calorimetry (DSC). It was found that radiation-induced links do not change the heat of fusion of polythylene crystals, but decrease the melt entropy and increase the fold surface free energy per unit area of the crystals. The carbon 13 NMR results demonstrate that long-chain branches (Y links) are formed much more frequently than H-shaped crosslinks at low absorbed doses. The Y links are produced by reactions of alkyl free radicals with terminal vinyl groups in polyethylene

  12. Mechanisms of transient radiation-induced creep

    International Nuclear Information System (INIS)

    Pyatiletov, Yu.S.

    1981-01-01

    Radiation-induced creep at the transient stage is investigated for metals. The situation, when several possible creep mechanisms operate simultaneously is studied. Among them revealed are those which give the main contribution and determine thereby the creep behaviour. The time dependence of creep rate and its relation to the smelling rate is obtained. The results satisfactorily agree with the available experimental data [ru

  13. Radiation-induced leukemias in ankylosing spondylitis

    International Nuclear Information System (INIS)

    Toolis, F.; Potter, B.; Allan, N.C.; Langlands, A.O.

    1981-01-01

    Three cases of leukemia occurred in patients with ankylosing spondylitis treated by radiotherapy. In each case, the leukemic process exhibited bizarre features suggesting that radiation is likely to induce atypical forms of leukemia possessing unusual attributes not shared by spontaneously developing leukemia. The likely distinctive aspects of radiation-induced leukemia are discussed

  14. Radiation induced crystallinity damage in poly(L-lactic acid)

    CERN Document Server

    Kantoglu, O

    2002-01-01

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

  15. Studies on radiation induced changes in bovine hemoglobin type A

    International Nuclear Information System (INIS)

    Wdzieczak, J.; Duda, W.; Leyko, W.

    1978-01-01

    In this paper the structural and functional changes of gamma irradiated bovine hemoglobin are presented. Aqueous solutions/1%/of HbO 2 were irradiated in air with doses ranging from 1 to 4 Mrad. Isoelectric focusing indicated change of the charge of irradiated hemoglobin. The isoelectric point of hemoglobin was displaced towards more acid values with increasing doses, up from 1 Mrad. Fingerprint analysis and peptide column chromatography of irradiated hemoglobin demonstrated disturbances increasing with the dose. These changes were confirmed by amino acid analysis which showed that Cys, Met, Trp, His, Pro and Tyr residues were destroyed or modified following irradiation. At doses exceeding 1 Mrad the irradiated solutions of hemoglobin showed a decrease of heme-heme interaction and an increase of affinity for oxygen. Differences observed in oxygen-dissociation curves seem to be correlated with the radiation induced destruction of amino acid residues which are responsible for the functional properties of hemoglobin. (auth.)

  16. Influence on DNA repair inhibitors on dominant lethal factors after gamma irradiation

    International Nuclear Information System (INIS)

    Engl, D.

    1978-01-01

    Experiments were performed in order to test the hypothesis of a correlation between ionizing radiation and DNA repair inhibition under in vivo conditions. In a biometrically planned dominant lethal test on mice, the repair inhibition on the male gametes by butazolidine, TWEEN 80 and vitamin A was studied after gamma irradiation at 20 rad/10 min. No effect was observed in the case of butazolidine and TWEEN 80, whereas the influence of a high concentration of vitamin A (1 million IE/kg) was just at the statistical significancy threshold. (G.G.)

  17. Molecular analysis of radiation-induced mutations in vitro

    International Nuclear Information System (INIS)

    Kronenberg, A.

    1996-01-01

    This review will focus on the nature of specific locus mutations detected in mammalian cells exposed in vitro to different types of ionizing radiations. Ionizing radiation has been shown to produce a wide variety of heritable alterations in DNA. These range from single base pair substitutions to stable loss or translocation of large portions of whole chromosomes. Data will be reviewed for certain test systems that reveal different mutation spectra. Techniques for the analysis of molecular alterations include applications of the polymerase chain reaction, some of which may be coupled with DNA sequence analysis, and a variety of hybridization-based techniques. The complexity of large scale rearrangements is approached with cytogenetic techniques including high resolution banding and various applications of the fluorescence in situ hybridization (FISH) technique. Radiation-induced mutant frequencies and mutation spectra are a function of the linkage constraints on the recovery of viable mutants for a given locus and test system. 44 refs

  18. Short-duration exposure to 2.45 GHz microwave radiation induces ...

    African Journals Online (AJOL)

    OBEMBE

    radiation induces DNA damage in Sprague Dawley rat's reproductive ... affect both male and female fertility adversely. ... 4% relative humidity. Exposures were whole body irradiation with the animal at 12 cm from the MW antenna of dimensions 12 x 5 cm. The animals were divided into ten groups of three males and three.

  19. Understanding the role of p53 in adaptive response to radiation-induced germline mutations

    International Nuclear Information System (INIS)

    Langlois, N.L.; Quinn, J.S.; Somers, C.M.; Boreham, D.R.; Mitchel, R.E.J.

    2003-01-01

    Full text: Radiation-induced adaptive response is now a widely studied area of radiation biology. Studies have demonstrated reduced levels of radiation-induced biological damage when an 'adaptive dose' is given before a higher 'challenge dose' compared to when the challenge dose is given alone. It has been shown in some systems to be a result of inducible cellular repair systems. The adaptive response has been clearly demonstrated in many model systems, however its impact on heritable effects in the mammalian germline has never been studied. Expanded Simple Tandem Repeat (ESTR) loci have been used as markers demonstrating that induced heritable mutations in mice follow a dose-response relationship. Recent data in our laboratory show preliminary evidence of radiation-induced adaptive response suppressing germline mutations at ESTR loci in wild type mice. The frequency of heritable mutations was significantly reduced when a priming dose of 0.1 Gy was given 24 hours prior to a 1 Gy acute challenging dose. We are now conducting a follow-up study to attempt to understand the mechanism of this adaptive response. P53 is known to play a significant role in governing apoptosis, DNA repair and cancer induction. In order to determine what function p53 has in the adaptive response for heritable mutations, we have mated radiation treated Trp53+/- male mice (C57Bl) to untreated, normal females (C57Bl). Using DNA fingerprinting, we are investigating the rate of inherited radiation-induced mutations on pre- and post-meiotic radiation-treated gametocytes by examining mutation frequencies in offspring DNA. If p53 is integral in the mechanism of adaptive response, we should not see an adaptive response in radiation-induced heritable mutations in these mice. This research is significant in that it will provide insight to understanding the mechanism behind radiation-induced adaptive response in the mammalian germline

  20. Ligase-deficient yeast cells exhibit defective DNA rejoining and enhanced gamma ray sensitivity

    International Nuclear Information System (INIS)

    Moore, C.W.

    1982-01-01

    Yeast cells deficient in DNA ligase were also deficient in their capacity to rejoin single-strand scissions in prelabeled nuclear DNA. After high-dose-rate gamma irradiation (10 and 25 krads), cdc9-9 mutant cells failed to rejoin single-strand scissions at the restrictive temperature of 37 0 C. In contrast, parental (CDC9) cells (incubated with mutant cells both during and after irradiation) exhibited rapid medium-independent DNA rejoining after 10 min of post-irradiation incubation and slower rates of rejoining after longer incubation. Parental cells were also more resistant than mutant cells to killing by gamma irradiation. Approximately 2.5 +- 0.07 and 5.7 +- 0.6 single-strand breaks per 10 8 daltons were detected in DNAs from either CDC9 or cdc9-9 cells converted to spheroplasts immediately after 10 and 25 krads of irradiation, respectively. At the permissive temperature of 23 0 C, the cdc9-9 cells contained 2 to 3 times the number of DNA single-strand breaks as parental cells after 10 min to 4 h of incubation after 10 krads of irradiation, and two- to eightfold more breaks after 10 min to 2.5 h of incubation after 25 krads of irradiation. Rejoining of single-strand scissions was faster in medium. After only 10 min in buffered growth medium after 10 krads of irradiation, the number of DNA single-strand breaks was reduced to 0.32 +- 0.3 (at 23 0 C) or 0.21 +- 0.05 (at 37 0 C) per 10 8 daltons in parental cells, but remained at 2.1 +- 0.06 (at 23 0 C) or 2.3 +- 0.07 (at 37 0 C) per 10 8 daltons in mutant cells. After 10 or 25 krads of irradiation plus 1 h of incubation in medium at 37 0 C, only DNA from CDC9 cells was rejoined to the size of DNA from unirradiated cells, whereas at 23 0 C, DNAs in both strains were completely rejoined

  1. Cell to Cell Variability of Radiation-Induced Foci: Relation between Observed Damage and Energy Deposition.

    Science.gov (United States)

    Gruel, Gaëtan; Villagrasa, Carmen; Voisin, Pascale; Clairand, Isabelle; Benderitter, Marc; Bottollier-Depois, Jean-François; Barquinero, Joan Francesc

    2016-01-01

    Most studies that aim to understand the interactions between different types of photon radiation and cellular DNA assume homogeneous cell irradiation, with all cells receiving the same amount of energy. The level of DNA damage is therefore generally determined by averaging it over the entire population of exposed cells. However, evaluating the molecular consequences of a stochastic phenomenon such as energy deposition of ionizing radiation by measuring only an average effect may not be sufficient for understanding some aspects of the cellular response to this radiation. The variance among the cells associated with this average effect may also be important for the behaviour of irradiated tissue. In this study, we accurately estimated the distribution of the number of radiation-induced γH2AX foci (RIF) per cell nucleus in a large population of endothelial cells exposed to 3 macroscopic doses of gamma rays from 60Co. The number of RIF varied significantly and reproducibly from cell to cell, with its relative standard deviation ranging from 36% to 18% depending on the macroscopic dose delivered. Interestingly, this relative cell-to-cell variability increased as the dose decreased, contrary to the mean RIF count per cell. This result shows that the dose effect, in terms of the number of DNA lesions indicated by RIF is not as simple as a purely proportional relation in which relative SD is constant with dose. To analyse the origins of this observed variability, we calculated the spread of the specific energy distribution for the different target volumes and subvolumes in which RIF can be generated. Variances, standard deviations and relative standard deviations all changed similarly from dose to dose for biological and calculated microdosimetric values. This similarity is an important argument that supports the hypothesis of the conservation of the association between the number of RIF per nucleus and the specific energy per DNA molecule. This comparison allowed us to

  2. Cell to Cell Variability of Radiation-Induced Foci: Relation between Observed Damage and Energy Deposition.

    Directory of Open Access Journals (Sweden)

    Gaëtan Gruel

    Full Text Available Most studies that aim to understand the interactions between different types of photon radiation and cellular DNA assume homogeneous cell irradiation, with all cells receiving the same amount of energy. The level of DNA damage is therefore generally determined by averaging it over the entire population of exposed cells. However, evaluating the molecular consequences of a stochastic phenomenon such as energy deposition of ionizing radiation by measuring only an average effect may not be sufficient for understanding some aspects of the cellular response to this radiation. The variance among the cells associated with this average effect may also be important for the behaviour of irradiated tissue. In this study, we accurately estimated the distribution of the number of radiation-induced γH2AX foci (RIF per cell nucleus in a large population of endothelial cells exposed to 3 macroscopic doses of gamma rays from 60Co. The number of RIF varied significantly and reproducibly from cell to cell, with its relative standard deviation ranging from 36% to 18% depending on the macroscopic dose delivered. Interestingly, this relative cell-to-cell variability increased as the dose decreased, contrary to the mean RIF count per cell. This result shows that the dose effect, in terms of the number of DNA lesions indicated by RIF is not as simple as a purely proportional relation in which relative SD is constant with dose. To analyse the origins of this observed variability, we calculated the spread of the specific energy distribution for the different target volumes and subvolumes in which RIF can be generated. Variances, standard deviations and relative standard deviations all changed similarly from dose to dose for biological and calculated microdosimetric values. This similarity is an important argument that supports the hypothesis of the conservation of the association between the number of RIF per nucleus and the specific energy per DNA molecule. This

  3. Evidence for Radiation-Induced Disseminated Intravascular Coagulation as a Major Cause of Radiation-Induced Death in Ferrets

    Energy Technology Data Exchange (ETDEWEB)

    Krigsfeld, Gabriel S.; Savage, Alexandria R.; Billings, Paul C.; Lin, Liyong; Kennedy, Ann R., E-mail: akennedy@mail.med.upenn.edu

    2014-03-15

    Purpose: The studies reported here were performed as part of a program in space radiation biology in which proton radiation like that present in solar particle events, as well as conventional gamma radiation, were being evaluated in terms of the ability to affect hemostasis. Methods and Materials: Ferrets were exposed to 0 to 2 Gy of whole-body proton or gamma radiation and monitored for 30 days. Blood was analyzed for blood cell counts, platelet clumping, thromboelastometry, and fibrin clot formation. Results: The lethal dose of radiation to 50% of the population (LD{sub 50}) of the ferrets was established at ∼1.5 Gy, with 100% mortality at 2 Gy. Hypocoagulability was present as early as day 7 postirradiation, with animals unable to generate a stable clot and exhibiting signs of platelet aggregation, thrombocytopenia, and fibrin clots in blood vessels of organs. Platelet counts were at normal levels during the early time points postirradiation when coagulopathies were present and becoming progressively more severe; platelet counts were greatly reduced at the time of the white blood cell nadir of 13 days. Conclusions: Data presented here provide evidence that death at the LD{sub 50} in ferrets is most likely due to disseminated intravascular coagulation (DIC). These data question the current hypothesis that death at relatively low doses of radiation is due solely to the cell-killing effects of hematopoietic cells. The recognition that radiation-induced DIC is the most likely mechanism of death in ferrets raises the question of whether DIC is a contributing mechanism to radiation-induced death at relatively low doses in large mammals.

  4. Comparison of chain breaks produced in DNA in vivo by gamma rays and neutrons; hypothesis of a new radiolesion in DNA

    Energy Technology Data Exchange (ETDEWEB)

    Elkert, B.; Pironin, M. (Institut Curie, Section de Biologie, 91 - Orsay (France)); Sabatier, R. (Centre Hospitalier Regional d' Orleans, Service de Neutrontherapie, C.N.R.S., 45 (France)); Latarjet, R.

    1985-06-21

    Using the method of alkaline elution for the treatment of cell DNA in chinese hamster fibroblasts irradiated with low doses of either cobalt-60 gamma rays or p (34 MeV) Be neutrons, we determined the kinetics of radioinduced strand breaks. The comparison gamma rays-neutrons reveals important discrepancies which suggest that neutrons induce a so for unknown reaction in DNA simultaneously with single and double strand breakage. This observation could contribute to explain the high RBE value of high LET particles.

  5. Comparison of chain breaks produced in DNA in vivo by gamma rays and neutrons; hypothesis of a new radiolesion in DNA

    International Nuclear Information System (INIS)

    Elkert, B.; Pironin, M.; Sabatier, R.; Latarjet, R.

    1985-01-01

    Using the method of alkaline elution for the treatment of cell DNA in chinese hamster fibroblasts irradiated with low doses of either cobalt-60 gamma rays or p (34 MeV) Be neutrons, we determined the kinetics of radioinduced strand breaks. The comparison gamma rays-neutrons reveals important discrepancies which suggest that neutrons induce a so for unknown reaction in DNA simultaneously with single and double strand breakage. This observation could contribute to explain the high RBE value of high LET particles [fr

  6. Studies on protective effects of superoxide dismutase on radiation induced-chromosomal aberrations

    International Nuclear Information System (INIS)

    Zheng Siying; Jiang Jiagui; Lin Xingcheng

    1987-09-01

    This study demonstrates that radiation induced-chromosomal aberrations are not only due to the direct effect of radiation h it , but the indirect effect of free radical as well. Therefore, chromosome damage induced by radiation may be reduced by adding exogenous SOD into the radiation exposed lymphocyte culture to eliminate the superoxide free radical which damages DNA. On the other hand, however, the radiosensitivity of lymphocytes can be raised by adding SOD inhibitor (DDC) into the lymphocyte culture, which makes radiation induced-chromosomal damages more severely

  7. Radiation-induced brain injury: A review

    International Nuclear Information System (INIS)

    Greene-Schloesser, Dana; Robbins, Mike E.; Peiffer, Ann M.; Shaw, Edward G.; Wheeler, Kenneth T.; Chan, Michael D.

    2012-01-01

    Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their

  8. The contribution of endogenous and exogenous effects to radiation-induced damage in the bacterial spore

    International Nuclear Information System (INIS)

    Jacobs, G.P.; Samuni, A.; Czapski, G.

    1985-01-01

    Radical scavengers such as polyethylene glycol 400 and 4000 and bovine albumin have been used to define the contribution of exogenous and endogenous effects to the gamma-radiation-induced damage in aqueous buffered suspensions of Bacillus pumilus spores. The results indicate that this damage in the bacterial spore is predominantly endogenous both in the presence of 1 atmosphere of oxygen, and in anoxia. (author)

  9. A review on radiation-induced nucleation and growth of colloidal metallic nanoparticles

    OpenAIRE

    Abedini, Alam; Daud, Abdul Razak; Abdul Hamid, Muhammad Azmi; Kamil Othman, Norinsan; Saion, Elias

    2013-01-01

    This review presents an introduction to the synthesis of metallic nanoparticles by radiation-induced method, especially gamma irradiation. This method offers some benefits over the conventional methods because it provides fully reduced and highly pure nanoparticles free from by-products or chemical reducing agents, and is capable of controlling the particle size and structure. The nucleation and growth mechanism of metallic nanoparticles are also discussed. The competition between nucleation ...

  10. Radiation-induced meningiomas in pediatric patients

    International Nuclear Information System (INIS)

    Moss, S.D.; Rockswold, G.L.; Chou, S.N.; Yock, D.; Berger, M.S.

    1988-01-01

    Radiation-induced meningiomas rarely have latency periods short enough from the time of irradiation to the clinical presentation of the tumor to present in the pediatric patient. Three cases of radiation-induced intracranial meningiomas in pediatric patients are presented. The first involved a meningioma of the right frontal region in a 10-year-old boy 6 years after the resection and irradiation of a 4th ventricular medulloblastoma. Review of our pediatric tumor cases produced a second case of a left temporal fossa meningioma presenting in a 15-year-old boy with a history of irradiation for retinoblastoma at age 3 years and a third case of a right frontoparietal meningioma in a 15-year-old girl after irradiation for acute lymphoblastic leukemia. Only three cases of meningiomas presenting in the pediatric age group after radiation therapy to the head were detected in our review of the literature

  11. Ionizing radiation induced malignancies in man

    International Nuclear Information System (INIS)

    Dutrillaux, B.

    1997-01-01

    Using data on gene and chromosome alterations in human cancers, it is proposed that most radiation induced cancers are a consequence of recessive mutations of tumor suppressor genes. This explains the long delay between radiation exposure and the cancer onset. As a consequence, radiation induced cancers belong to groups of tumors where no specific translocations (forming or activating oncogenes) but multiple unbalanced chromosome rearrangements (deletions unmasking recessive mutations) exist. This explains why osteosarcomas, malignant fibrous histiocytoma, chondrosarcomas are frequently induced, but not liposarcoma, Ewing sarcomas and rhabdomyosarcomas, among others. A single exception confirms this rule: papillary thyroid cancer, frequently induced in exposed children, in which structural rearrangements frequently form a RET/PTC3 fusion gene. This fusion gene is the results of the inversion of a short segment of chromosome 10, and it is assumed that such rearrangement (small para-centric inversion) can easily occur after exposure to radiations, at contrast with translocations between to genes belonging to different chromosomes. (author)

  12. Bile acids in radiation-induced diarrhea

    International Nuclear Information System (INIS)

    Arlow, F.L.; Dekovich, A.A.; Priest, R.J.; Beher, W.T.

    1987-01-01

    Radiation-induced bowel disease manifested by debilitating diarrhea is an unfortunate consequence of therapeutic irradiation for pelvic malignancies. Although the mechanism for this diarrhea is not well understood, many believe it is the result of damage to small bowel mucosa and subsequent bile acid malabsorption. Excess amounts of bile acids, especially the dihydroxy components, are known to induce water and electrolyte secretion and increase bowel motility. We have directly measured individual and total bile acids in the stool samples of 11 patients with radiation-induced diarrhea and have found bile acids elevated two to six times normal in eight of them. Our patients with diarrhea and increased bile acids in their stools had prompt improvement when given cholestyramine. They had fewer stools and returned to a more normal life-style

  13. Radiation induced transformation of CO in cyclohexane

    International Nuclear Information System (INIS)

    Lugovoi, Y.M.; Park, H.-R.; Getoff, N.

    1989-01-01

    The radiation induced incorporation of CO in cyclohexane leads to formation of: bicyclohexylketone (G i = 2.40), α,α-bicyclohexyldiketone (G i = 0.90), cyclohexanone (G i = 0.24), cyclohexanol (G i = 0.20), cyclohexanecarboxylic acid (G i 0.10), in addition to bicyclohexyl (G i = 1.30) and polymers. The G i -values are strongly dependent on the CO-concentration in the solution. Probable reaction mechanisms are presented. (author)

  14. Radiation induced glioblastoma. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Naoki; Kayama, Takamasa; Sakurada, Kaori; Saino, Makoto; Kuroki, Akira [Yamagata Univ. (Japan). School of Medicine

    2000-05-01

    We report a surgical case of a 54-year-old woman with a radiation induced glioblastoma. At the age of 34, the patient was diagnosed to have a non-functioning pituitary adenoma. It was partially removed followed by 50 Gy focal irradiation with a 5 x 5 cm lateral opposed field. Twenty years later, she suffered from rapidly increasing symptoms such as aphasia and right hemiparesis. MRI showed a large mass lesion in the left temporal lobe as well as small mass lesions in the brain stem and the right medial temporal lobe. These lesions situated within the irradiated field. Magnetic resonance spectroscopy revealed relatively high lactate signal and decreased N-acetyl aspartate, choline, creatine and phosphocreatine signals. Increased lactate signal meant anaerobic metabolism that suggested the existence of a rapidly growing malignant tumor. Thus, we planned surgical removal of the left temporal lesion with the diagnosis of a radiation induced malignant glioma. The histological examination revealed a glioblastoma with radiation necrosis. MIB-1 staining index was 65%. Postoperatively, her symptoms improved, but she died from pneumonia 1 month after the surgery. A autopsy was obtained. The lesion of the left temporal lobe was found to have continuity to the lesion in the midbrain, the pons and the right temporal lobe as well. High MIB-1 staining index suggested that a radiation induced glioblastoma had high proliferative potential comparing with a de novo and secondary glioblastoma. (author)

  15. Genetic alterations during radiation-induced carcinogenesis

    International Nuclear Information System (INIS)

    Kodama, Seiji

    1995-01-01

    This paper reviews radiation-induced genetic alterations and its carcinogenesis, focusing on the previous in vitro assay outcome. A colony formation assay using Syrian hamster fetal cells and focus formation assay using mouse C3H10T1/2 cells are currently available to find malignant transformation of cells. Such in vitro assays has proposed the hypothesis that radiation-induced carcinogenesis arises from at least two-stage processes; i.e., that an early step induced by irradiation plays an important role in promoting the potential to cause the subsequent mutation. A type of genetic instability induced by radiation results in a persistently elevated frequency of spontaneous mutations, so-called the phenomenon of delayed reproductive death. One possible mechanism by which genetic instability arises has been shown to be due to the development of abnormality in the gene group involved in the maintenance mechanism of genome stability. Another possibility has also been shown to stem from the loss of telomere (the extremities of a chromosome). The importance of search for radiation-induced genetic instability is emphasized in view of the elucidation of carcinogenesis. (N.K.)

  16. Wheat Germ Oil Attenuates Gamma Radiation-Induced Skeletal ...

    African Journals Online (AJOL)

    Muscular strength is important in sport as well as in daily activities. Exposure to ionizing radiation is thought to increase oxidative stress and damage muscle tissue. Wheat germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be ...

  17. Gamma-radiation-induced interactions between amino acids and glucagon

    International Nuclear Information System (INIS)

    Mee, L.K.; Kim, H.J.; Adelstein, S.J.; Taub, I.A.

    1984-01-01

    The interaction of glucagon and phenylalanine mediated by the OH. radical causes formation of higher molecular weight products of glucagon and phenylalnine, loss of amino acid residues in glucagon, and formation of adducts of glucagon and phenylalanine. The relative yields of these products depend upon the molar ratio of phenylalanine to glucagon in solution. At low ratios, glucagon aggregation and loss of amino acid residues predominate; at high ratios, the formation of phenylalanine dimers (and possible trimers and tetramers) predominates. The formation of adducts reaches a maximum at a phenylalanine:glucagon molar ratio of 3-4, and then decreases gradually, as the molar ratio increases, but is still discernible even at high molar ratios. Mechanisms for the formation of adducts are suggested. The influence of the primary aqueous radical intermediates, OH., H., and e - /sub aq/, on adduct formation has been evaluated for several different amino acids by irradiating in the presence of specific radical scavengers. For the aromatic amino acids (phenylalanine, tryptophan, and tyrosine), OH. is considerably more effective than e - /sub aq/ for mediating adduct formation, whereas for histidine and methionine, these primary radicals are equally effective

  18. DNA Damage in Melania Snail (Semisulcospira libertine) Irradiated with Gamma Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Tae Ho; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Advanced Radiation Technology Institute, Jeongeup (Korea, Republic of); An, Kwang Guk [Chungnam National University, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-10-15

    Generally radiological protection has focused on human. But International Commission on Radiological Protection (ICRP) requires the effect data of ionizing radiation on nonhuman biota for the radiological protection of the environment. The choice of a melania snail as a model for environmental biomonitoring of radiation genotoxicity took into account that invertebrates represent one of aquatic species. The comet assay or single cell gel electrophoresis (SCGE) assay, first introduced by Ostling and Johanson, was used to detect DNA single strand breaks and to investigate the application of this technique as a tool for aquatic biomonitoring. Comet assay offers considerable advantages over some other assays used in DNA damage detection, such as chromosomal aberrations, sister chromatid Exchange and the micronucleus test, since there is no need for cells to be in a dividing state. Other advantages are its rapidity, relatively low coast, and wide applicability to virtually any nucleated cell type. In this study, we evaluated DNA damage in cells of Semisulcospira libertina after irradiation with {sup 60}Co gamma radiation by using the comet assay

  19. Pathogenicity in POLG syndromes: DNA polymerase gamma pathogenicity prediction server and database.

    Science.gov (United States)

    Nurminen, Anssi; Farnum, Gregory A; Kaguni, Laurie S

    2017-06-01

    DNA polymerase gamma (POLG) is the replicative polymerase responsible for maintaining mitochondrial DNA (mtDNA). Disorders related to its functionality are a major cause of mitochondrial disease. The clinical spectrum of POLG syndromes includes Alpers-Huttenlocher syndrome (AHS), childhood myocerebrohepatopathy spectrum (MCHS), myoclonic epilepsy myopathy sensory ataxia (MEMSA), the ataxia neuropathy spectrum (ANS) and progressive external ophthalmoplegia (PEO). We have collected all publicly available POLG-related patient data and analyzed it using our pathogenic clustering model to provide a new research and clinical tool in the form of an online server. The server evaluates the pathogenicity of both previously reported and novel mutations. There are currently 176 unique point mutations reported and found in mitochondrial patients in the gene encoding the catalytic subunit of POLG, POLG . The mutations are distributed nearly uniformly along the length of the primary amino acid sequence of the gene. Our analysis shows that most of the mutations are recessive, and that the reported dominant mutations cluster within the polymerase active site in the tertiary structure of the POLG enzyme. The POLG Pathogenicity Prediction Server (http://polg.bmb.msu.edu) is targeted at clinicians and scientists studying POLG disorders, and aims to provide the most current available information regarding the pathogenicity of POLG mutations.

  20. 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

  1. Cell cycle regulation and radiation-induced cell death

    International Nuclear Information System (INIS)

    Favaudon, V.

    2000-01-01

    Tight control of cell proliferation is mandatory to prevent cancer formation as well as to normal organ development and homeostasis. This occurs through checkpoints that operate in both time and space and are involved in the control of numerous pathways including DNA replication and transcription, cell cycle progression, signal transduction and differentiation. Moreover, evidence has accumulated to show that apoptosis is tightly connected with the regulation of cell cycle progression. In this paper we describe the main pathways that determine checkpoints in the cell cycle and apoptosis. It is also recalled that in solid tumors radiation-induced cell death occurs most frequently through non-apoptotic mechanisms involving oncosis, and mitotic or delayed cell death. (author)

  2. Radiation-induced bystander effects in vivo are sex specific

    International Nuclear Information System (INIS)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry; Kovalchuk, Olga

    2008-01-01

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naive cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes

  3. Cytosine modifications after gamma irradiation in aerated aqueous solution of Escherichia coli DNA

    International Nuclear Information System (INIS)

    Polverelli, M.

    1983-04-01

    After gamma irradiation of cytosine in aerated aqueous solution and utilization of various spectrometric methods (mass spectrometry, proton nuclear magnetic resonance and infrared spectrometry) about ten new radiolysis products were identified. The formation of N-glycolylbiuret in H 2 18 O aqueous solution of irradiated cytosine at pH 4,5 indicated that the preferred 18 OH hydroxyl radical attack was at C-5. The formation of trans 1-carbamoyl-4,5 dihydroxyimidazolidin-2 oxo which is the major product after cytosine pyrimidine ring rearrangement took place preferentially at neutral pH, while N-glycolylbiuret predominated at pH 4,5. The deamination pathway was predominant when cytosine was irradiated at acidic pH values (pH 2 ) or in copper complexes. The development of a new acid hydrolysis method using fluorhydric acid stabilized in pyridine made easier the evaluation of cytosine modifications after gamma irradiation in aerated aqueous solution of E. Coli DNA- 14 C-2 cytosine. This hydrolytic agent removed the modified bases from the polynucleotidic chain. A difference was found between the proportion of radiolytic products removed by acid hydrolysis and by irradiation of the free base in solution [fr

  4. Role of rosemary leaves extract against radiation-induced hematological and biochemical alterations in mice

    International Nuclear Information System (INIS)

    Acharya, G. S.; Goyal, P. K.

    2008-01-01

    The present paper is a study of the modulatory effect of Rosmarinus officinalis leaves extract on radiation-induced hematological and biochemical changes in Swiss albino mice.The dose reduction factor for the Rosemary extract against gamma rays was calculated 1.53 from LD 50/30 values. The Rosemary extract was administered orally for 5 consecutive days prior to radiation exposure. The hematological and biochemical parameters were assessed from day 1 to 30 post-irradiation intervals. The total erythrocyte count, total leucocytes count, hemoglobin, and hematocrit values in the experimental group were found to be elevated as compared to the control group of mice. Furthermore, the Rosemary extract treatment enhanced reduced glutathione content in the liver and blood against radiation-induced depletion. Treatment with the plant extract brought a significant fall in the lipid peroxidation level, suggesting rosemary's role in protection against radiation-induced membrane and cellular damage. The results from the present study suggest a radio-protective effect of the Rosemary extract against radiation-induced hematological and biochemical alterations in mice. (author)

  5. Gamma and Ion-Beam Irradiation of DNA: Free Radical Mechanisms, Electron Effects, and Radiation Chemical Track Structure

    Science.gov (United States)

    Sevilla, Michael D.; Becker, David; Kumar, Anil; Adhikary, Amitava

    2016-01-01

    The focus of our laboratory’s investigation is to study the direct-type DNA damage mechanisms resulting from γ-ray and ion-beam radiation-induced free radical processes in DNA which lead to molecular damage important to cellular survival. This work compares the results of low LET (γ−) and high LET (ion-beam) radiation to develop a chemical track structure model for ion-beam radiation damage to DNA. Recent studies on protonation states of cytosine cation radicals in the N1-substituted cytosine derivatives in their ground state and 5-methylcytosine cation radicals in ground as well as in excited state are described. Our results exhibit a radical signature of excitations in 5-methylcytosine cation radical. Moreover, our recent theoretical studies elucidate the role of electron-induced reactions (low energy electrons (LEE), presolvated electrons (epre−), and aqueous (or, solvated) electrons (eaq−)). Finally DFT calculations of the ionization potentials of various sugar radicals show the relative reactivity of these species. PMID:27695205

  6. Radiation-induced diffusion at ionic etching

    International Nuclear Information System (INIS)

    Protsenko, A.N.; Chajkovskij, Eh.F.

    1986-01-01

    Effect of radiation-induced diffusion (RID) on profiles of cesium implanted into tantalum, tungsten and molybdenum with 100 keV energy was studied. Layer-by-layer analysis was performed by means of 4 keV argon ions and 100 μA/cm 2 beam density. For the case under investigation an integral equation, which solution permitted to determine impurity true distribution, has been derived. It is shown that RID taking place on ionic etching results in broadening and shifting cesium profiles peaks into the deep of a specimen and so perverts results of the layer-by-layer analysis

  7. Radiation-induced cerebrovascular disease in children

    International Nuclear Information System (INIS)

    Wright, T.L.; Bresnan, M.J.

    1976-01-01

    Radiation-induced internal carotid artery occlusion has not been well recognized previously as a cause of childhood cerebrovascular disease. A child who had received radiation as a neonate for a hemangioma involving the left orbit at the age of 6 years experienced a recurrent right-sided paresis, vascular headaches, and speech difficulties. Angiography showed a hypoplastic left carotid artery with occlusion of both the anterior and middle cerebral arteries. Collateral vessels bypassed the occluded-stenotic segments. Review of the literature showed two additional cases of large vessel occlusion in childhood associated with anastomatic telangiectatic vessel development following early radiation therapy of facial hemangioma

  8. A report on radiation-induced gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Salvati, M.; Artico, M.; Caruso, R.; Rocchi, G.; Orlando, E.R.; Nucci, F. (Univ. of Rome La Sapienza (Italy))

    1991-01-15

    Radiation-induced gliomas are uncommon, with only 73 cases on record to date. The disease that most frequently occasioned radiation therapy has been acute lymphoblastic leukemia (ALL). Three more cases are added here, two after irradiation for ALL and one after irradiation for tinea capitis. In a review of the relevant literature, the authors stress the possibility that the ALL-glioma and the retinoblastoma-glioma links point to syndromes in their own right that may occur without radiation therapy.56 references.

  9. Radiation induced liver disease: A clinical update

    International Nuclear Information System (INIS)

    Benson, R.; Madan, R.; Chander, S.; Kilambi, R.

    2016-01-01

    Radiation-induced liver disease (RILD) or radiation hepatitis is a sub-acute form of liver injury due to radiation. It is one of the most dreaded complications of radiation which prevents radiation dose escalation and re irradiation for hepatobiliary or upper gastrointestinal malignancies. This complication should be kept in mind whenever a patient is planned for irradiation of these malignancies. Although, incidence of RILD is decreasing due to better knowledge of liver tolerance, improved investigation modalities and modern radiation delivery techniques, treatment options are still limited. In this review article, we have focussed on pathophysiology, risk factors, prevention and management of RILD

  10. Radiation-induced damage of membranes

    International Nuclear Information System (INIS)

    Yonei, Shuji

    1977-01-01

    An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

  11. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection.

    Science.gov (United States)

    Mishra, Om P; Popov, Anatoliy V; Pietrofesa, Ralph A; Christofidou-Solomidou, Melpo

    2016-09-01

    Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3'-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton (1)H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO(-) and radiation. Purine base chlorination by ClO(-) and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Chloride anions (Cl(-)) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by (1)H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO(-) or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO(-) generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl) and dichloro radical anions (Cl2¯)), which were trapped by SDG and its structural analog dopamine. We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged

  12. Antioxidant activity of capsaicin on radiation-induced oxidation of murine hepatic mitochondrial membrane preparation

    Directory of Open Access Journals (Sweden)

    Gangabhagirathi R

    2015-06-01

    Full Text Available Ramachandran Gangabhagirathi,1 Ravi Joshi,2 1Bioorganic Division, 2Radiation and Photochemistry Division, Bhabha Atomic Research Center, Trombay, Mumbai, India Abstract: Capsaicin is the major capsaicinoid in chili peppers and is widely used as a spice. It is also used for topical applications in cases of peripheral neuropathy. The present study deals with its role in modulation of gamma radiation-induced damages of the biochemical constituents of rat liver mitochondrial membrane (RLM preparation. The extent of lipid hydroperoxide formation, depletion in protein thiols, and formation of protein carbonyls have been biochemically assessed in the presence of varying concentrations of capsaicin in RLM. Decrease in the activities of the important antioxidant enzyme superoxide dismutase, which is involved in the scavenging of free radicals, and the mitochondrial marker enzyme succinate dehydrogenase have been also looked into. Capsaicin has been found to efficiently inhibit radiation-induced biochemical alterations, namely lipid peroxidation and protein oxidation. It also significantly prevented radiation-induced loss in the activity of antioxidant enzyme and the important endogenous antioxidant glutathione. The study suggests that capsaicin can act as an antioxidant and radioprotector in physiological systems. Keywords: capsaicin, gamma radiation, radioprotection, lipid peroxidation, protein oxidation, enzyme activity

  13. Study of radiation-induced chromosomal aberrations

    International Nuclear Information System (INIS)

    Wolfring, E.

    2004-06-01

    A method for determining chromosomal aberrations was established for the purpose of examining the relative biological effectiveness (RBE) of photon radiation with respect to mammary epithelium cells. Cells were exposed to 25 kV X-radiation and to 200 kV X-radiation for comparison and the resulting concentrations of chromosomal aberrations were compared. The RBE M value for radiation-induced fragmentation was found to be 4.2 ± 2.4, while the RBE M value for radiation-induced generation of dicentric chromosomes was found to be 0.5 ± 0.5. In addition to the evaluation of chromosomal aberrations the number of cell cycles undergone by the cells was monitored by means of BrDU staining. As expected, the proportion of cells which underwent more than one cell cycle following exposure to 5 Gy was very low in both cases, amounting to 1.9% (25 kV) and 3.2 (200 kV). Non-radiated cells yielded control values of 26.0% and 12.6%, suggesting variations in external conditions from day to day

  14. Cell kinetic studies on radiation induced leukemogenesis

    International Nuclear Information System (INIS)

    Nakao, Isamu; Suzuki, Gen; Imai, Yasufumi; Kawase, Yoshiko; Nose, Masako; Hirashima, Kunitake; Bessho, Masami

    1989-01-01

    The purpose of this study was threefold: (1) to determine the clonal origin of radiation-induced thymic lymphoma in mice with cellular mosaicism for phosphoglycerate kinase; (2) to determine the incidence and latent period of myeloid leukemia and thymic lymphoma induced by whole-body exposure to median doses (3.0 Gy or less) in RFM/MsNrs-2 mice; and (3) to examine the influence of human recombinant interleukin-2 (hrIL-2). Thymic lymphoma was of a single cell origin. The incidence of radiation-induced myeloid leukemia and thymic lymphoma in RFM mice increased in a dose dependent fashion. Mean latent periods of both myeloid leukemia and thymic lymphoma after irradiation became shorter in proportion to radiation doses. When hrIL-2 was injected to RFM mice receiving 3.0 Gy, mean survivals were shorter in thymoma-bearing mice than the control mice. This suggested that hrIL-2 shortens the promotion step of thymoma. Administration of hrIL-2 failed to alter the incidence of myeloid leukemia or the mean survival of mice having myeloid leukemia, indicating that the protocol of hrIL-2 administration was not so sufficient as to alter the myeloid leukemogenesis. (Namekawa, K)

  15. Effect of pH on radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Chang, W. Song; Park, Heon J.; Lyons, John C.; Auger, Elizabeth A.; Lee, Hyung-Sik

    1996-01-01

    Purpose/Objective: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Materials and Methods: SCK mammary adenocarcinoma cells of A/J mice were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 degree sign C for 24-120 hrs., the extent of apoptosis was determined using agarose gel electrophoresis of DNA, in situ TUNEL staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The membrane integrity, using the trypan blue exclusion method, and the clonogenicity of the cells were also determined. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in pH 7.5 medium within 48 hrs. The radiation-induced apoptosis progressively declined as the medium pH was lowered so that little apoptosis occurred in 48 hrs. after irradiation with 12 Gy in pH 6.6 medium. However, when the cells were irradiated and incubated for 48 hrs. in pH 6.6 medium and then medium was replaced with pH 7.5 medium, apoptosis promptly occurred. Apoptosis also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 hrs. or longer post-irradiation before incubation in pH 6.6 medium. Conclusion: An acidic environment markedly suppresses radiation-induced apoptosis probably by suppressing the expression of initial signals responsible for irradiation-induced apoptosis. Indications are that the signals persist in an acidic environment and trigger apoptosis when the environmental acidity is eased. Our results suggest that the acidic environment in human tumors may inhibit the apoptosis after irradiation. However, apoptosis may be triggered when reoxygenation occurs after irradiation, and thus, the intratumor environment becomes less acidic after irradiation. Not only the change in pO 2 but the change in pH during the course of fractionated radiotherapy may greatly influence the outcome of the treatment

  16. Low LET radiation-induced telomerase catalytic subunit promoter activation is mediated by nuclear factor Kappa B

    International Nuclear Information System (INIS)

    Natarajan, M.; Hong, F.A.; Mohan, S.; Herman, T.S.

    2003-01-01

    Full text: The objective of this study is to understand whether low doses of low LET radiation induces survival advantage in normal cells. As an increase in telomerase activity is associated with longevity and cell proliferation, we examined the telomerase response following gamma-irradiation in normal aortic endothelial cells. Telomeric Repeat Amplification Protocol assay following low LET radiation showed an increase in telomerase enzyme activity as early as 8 h post irradiation and reaches its maximum at 24 h. Subsequent analysis revealed that the increased telomerse enzyme activity is due to increased synthesis resulting from an increased transcription. Examination of transcriptional activation of telomerase reverse transcriptase (TERT) promoter regulation showed an enhanced transcription of the telomerse gene following gamma-irradiation. In our previous reports we documented an increase in NF-kB DNA-binding property following low LET radiation (3). Therefore, to determine whether the activation of NF-kB-signaling is responsible for induced TERT promoter activation, cells transiently transfected with minimal promoter region of TERT containing wild type or mutant NF-kB binding site were examined following low LET radiation. TERT promoter activation was induced in wild type transfected cells whereas, in mutant kB binding site, the activation remained at the basal level similar to that of un-irradiated cells. More significantly, the gamma-ray mediated promoter activation of telomerase gene as well as induce telomerase enzyme activity was abrogated by ectopically expressing the IkBa mutant (IkBa (S32A/S36A)), which blocks NF-kB activation. The results thus suggest that exposure to low LET radiation could induce telomerase activity and the activation is at least, in part, mediated by the transcription factor NF-kB. Sustained activation of telomerase in these cells after low LET radiation may impart extended life span

  17. Bystander effects in radiation-induced genomic instability

    Science.gov (United States)

    Morgan, William F.; Hartmann, Andreas; Limoli, Charles L.; Nagar, Shruti; Ponnaiya, Brian

    2002-01-01

    Exposure of GM10115 hamster-human hybrid cells to X-rays can result in the induction of chromosomal instability in the progeny of surviving cells. This instability manifests as the dynamic production of novel sub-populations of cells with unique cytogenetic rearrangements involving the "marker" human chromosome. We have used the comet assay to investigate whether there was an elevated level of endogenous DNA breaks in chromosomally unstable clones that could provide a source for the chromosomal rearrangements and thus account for the persistent instability observed. Our results indicate no significant difference in comet tail measurement between non-irradiated and radiation-induced chromosomally unstable clones. Using two-color fluorescence in situ hybridization we also investigated whether recombinational events involving the interstitial telomere repeat-like sequences in GM10115 cells were involved at frequencies higher than random processes would otherwise predict. Nine of 11 clones demonstrated a significantly higher than expected involvement of these interstitial telomere repeat-like sequences at the recombination junction between the human and hamster chromosomes. Since elevated levels of endogenous breaks were not detected in unstable clones we propose that epigenetic or bystander effects (BSEs) lead to the activation of recombinational pathways that perpetuate the unstable phenotype. Specifically, we expand upon the hypothesis that radiation induces conditions and/or factors that stimulate the production of reactive oxygen species (ROS). These reactive intermediates then contribute to a chronic pro-oxidant environment that cycles over multiple generations, promoting chromosomal recombination and other phenotypes associated with genomic instability.

  18. Radiation-induced apoptosis of lymphocytes in peripheral blood

    International Nuclear Information System (INIS)

    Oh, Yoon Kyeong; Lee, Tae Bum; Nam, Taek Keun; Kee, Keun Hong; Choi, Cheol Hee

    2003-01-01

    This study quantitatively evaluated the apoptosis in human peripheral blood lymphocytes using flow cytometry, and investigated the possibility of using this method, with a small amount of blood, and the time and dose dependence of radiation-induced apoptosis. Peripheral blood lymphocytes were isolated from the heparinized venous blood of 11 healthy volunteers, 8 men and 3 women, with each 10 ml of blood being divided into 15 samples. The blood lymphocytes were irradiated using a linear accelerator at a dose rate of 2.4 Gy/min, to deliver doses of 0.5, 1, 2 and 5 Gy. The control samples, and irradiated cells, were maintained in culture medium for 24, 48 and 72 hours following the irradiation. The number of apoptotic cells after the in vitro X-irradiation was measured by flow cytometry after incubation periods of 24, 48 and 72 hours. We also observed the apoptotic cells using a DNA fragmentation assay and electron microscopy. The rate of spontaneous apoptosis increased in relation to the time interval following irradiation (1.761±0.161, 3.563±0.564, 11.098±2.849, at 24, 48, and 72 hours). The apoptotic cells also increased in the samples irradiated with 0.5, 1, 2 and 5 Gy, in a radiation dose and time interval after irradiation manner, with the apoptosis being too great at 72 hours after irradiation. The dose-response curves were characterized by an initial steep increase in the number of apoptotic cells for irradiation doses below 2 Gy, with a flattening of the curves as the dose approached towards 5 Gy. The flow cytometric assay technique yielded adequate data, and required less than 1 mL of blood. The time and dose dependence of the radiation-induced apoptosis, was also shown. It is suggested that the adequate time interval required for the evaluation of apoptosis would be 24 to 48 hours after blood sampling

  19. Role of neurotensin in radiation-induced hypothermia in rats

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, S.B.; Hunt, W.A.; Harris, A.H. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

    1991-05-01

    The role of neurotensin in radiation-induced hypothermia was examined. Intracerebroventricular (ICV) administration of neurotensin produced dose-dependent hypothermia. Histamine appears to mediate neurotensin-induced hypothermia because the mast cell stabilizer disodium cromoglycate and antihistamines blocked the hypothermic effects of neurotensin. An ICV pretreatment with neurotensin antibody attenuated neurotensin-induced hypothermia, but did not attenuate radiation-induced hypothermia, suggesting that radiation-induced hypothermia was not mediated by neurotensin.

  20. Radiation-induced color centers in La-doped PbWO sub 4 crystals

    CERN Document Server

    Deng, Q; Zhu, R Y

    1999-01-01

    This report presents the result of a study on radiation-induced color center densities in La-doped lead tungstate (PbWO sub 4) crystals. The creation and annihilation constants of radiation-induced color centers were determined by using transmittance data measured for a PbWO sub 4 sample before and during sup 6 sup 0 Co gamma-ray irradiation at a dose rate of 15 rad/h. Following a model of color center kinetics, these constants were used to calculate color center densities under irradiations at 100 rad/h. The result was found to be in good agreement with experimental data, indicating that the behaviour of PbWO sub 4 crystals under irradiation can be predicted according to this model.

  1. Radiation-Induced Testicular Injury and Its Amelioration by Tinospora cordifolia (An Indian Medicinal Plant Extract

    Directory of Open Access Journals (Sweden)

    Priyanka Sharma

    2011-01-01

    Full Text Available The primary objective of this investigation is to determine the deleterious effects of sub lethal gamma radiation on testes and their possible inhibition by Tinospora cordifolia extract (TCE. For this purpose, one group of male Swiss albino mice was exposed to 7.5 Gy gamma radiation to serve as the irradiated control, while the other group received TCE (75 mg/kg b. wt./day orally for 5 consecutive days half an hr before irradiation to serve as experimental. Exposure of animals to 7.5 Gy gamma radiation resulted into significant decrease in body weight, tissue weight, testes- body weight ratio and tubular diameter up to 15 days of irradiation. Cent percent mortality was recorded by day 17th in irradiated control, whereas all animals survived in experimental group. TCE pretreatment rendered significant increase in body weight, tissue weight, testes- body weight ratio and tubular diameter at various intervals as compared to irradiated group. Radiation induced histological lesions in testicular architecture were observed more severe in irradiated control then the experimental. TCE administration before irradiation significantly ameliorated radiation induced elevation in lipid peroxidation and decline in glutathione concentration in testes. These observations indicate the radio- protective potential of Tinospora cordifolia root extract in testicular constituents against gamma irradiation in mice.

  2. Prevention Of Radiation Induced Hematological Alterations By ...

    African Journals Online (AJOL)

    The modulatory influence of Rosmarinus officinalis (rosemary) leaves extract was investigated in Swiss albino mice at a dose of 3 Gy gamma radiation. For this purpose, adult Swiss albino mice were irradiated with 3 Gy gamma rays in the presence (experimental) or absence (control) of rosemary (1000 mg/kg body wt.).

  3. 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.

  4. Detection of radiation-induced lesions in the myc proto-oncogene

    International Nuclear Information System (INIS)

    Grossi, G.F.; Roots, R.; Tobias, C.A.

    1985-01-01

    Alterations in a certain group of genes, the proto-oncogenes, are known to be associated with changes in cell biochemistry and carcinogenesis. The authors chose the Indian male muntjac cell with a total chromosome number of 2N = 7, in which to study the effects of radiation-induced aberrations in the c-myc proto-oncogene. By routine hybridization techniques the authors have shown v-myc homology in total genomic DNA after digestion with Eco R1 and Bam H1. The first task is to identify the chromosomal site of the c-myc gene in these cells. They are doing this by hybridization of the v-myc probe either to the DNA extracted from sorted chromosomes or by the more precise in situ hybridization technique of chromosome spreads. The second task and principal aim is to study the effects of radiation-induced lesions and chromosomal rearrangements in the c-myc gene region

  5. Base substitutions, frameshifts, and small deletions constitute ionizing radiation-induced point mutations in mammalian cells

    International Nuclear Information System (INIS)

    Grosovsky, A.J.; de Boer, J.G.; de Jong, P.J.; Drobetsky, E.A.; Glickman, B.W.

    1988-01-01

    The relative role of point mutations and large genomic rearrangements in ionizing radiation-induced mutagenesis has been an issue of long-standing interest. Recent studies using Southern blotting analysis permit the partitioning of ionizing radiation-induced mutagenesis in mammalian cells into detectable deletions and major genomic rearrangements and into point mutations. The molecular nature of these point mutations has been left unresolved; they may include base substitutions as well as small deletions, insertions, and frame-shifts below the level of resolution of Southern blotting analysis. In this investigation, we have characterized a collection of ionizing radiation-induced point mutations at the endogenous adenine phosphoribosyltransferase (aprt) locus of Chinese hamster ovary cells at the DNA sequence level. Base substitutions represented approximately equal to 2/3 of the point mutations analyzed. Although the collection of mutants is relatively small, every possible type of base substitution event has been recovered. These mutations are well distributed throughout the coding sequence with only one multiple occurrence. Small deletions represented the remainder of characterized mutants; no insertions have been observed. Sequence-directed mechanisms mediated by direct repeats could account for some of the observed deletions, while others appear to be directly attributable to radiation-induced strand breakage

  6. Mechanism of loading the Escherichia coli DNA polymerase III beta sliding clamp on DNA. Bona fide primer/templates preferentially trigger the gamma complex to hydrolyze ATP and load the clamp.

    Science.gov (United States)

    Ason, Brandon; Handayani, Renita; Williams, Christopher R; Bertram, Jeffrey G; Hingorani, Manju M; O'Donnell, Mike; Goodman, Myron F; Bloom, Linda B

    2003-03-21

    The Escherichia coli DNA polymerase III gamma complex clamp loader assembles the ring-shaped beta sliding clamp onto DNA. The core polymerase is tethered to the template by beta, enabling processive replication of the genome. Here we investigate the DNA substrate specificity of the clamp-loading reaction by measuring the pre-steady-state kinetics of DNA binding and ATP hydrolysis using elongation-proficient and deficient primer/template DNA. The ATP-bound clamp loader binds both elongation-proficient and deficient DNA substrates either in the presence or absence of beta. However, elongation-proficient DNA preferentially triggers gamma complex to release beta onto DNA with concomitant hydrolysis of ATP. Binding to elongation-proficient DNA converts the gamma complex from a high affinity ATP-bound state to an ADP-bound state having a 10(5)-fold lower affinity for DNA. Steady-state binding assays are misleading, suggesting that gamma complex binds much more avidly to non-extendable primer/template DNA because recycling to the high affinity binding state is rate-limiting. Pre-steady-state rotational anisotropy data reveal a dynamic association-dissociation of gamma complex with extendable primer/templates leading to the diametrically opposite conclusion. The strongly favored dynamic recognition of extendable DNA does not require the presence of beta. Thus, the gamma complex uses ATP binding and hydrolysis as a mechanism for modulating its interaction with DNA in which the ATP-bound form binds with high affinity to DNA but elongation-proficient DNA substrates preferentially trigger hydrolysis of ATP and conversion to a low affinity state.

  7. Solvent influence during radiation induced grafting of styrene in PVDF

    International Nuclear Information System (INIS)

    Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B.

    2013-01-01

    Radiation-induced grafting was studied to produce styrene grafted poly(vinylidene fluoride) (PVDF) membranes. PVDF films with 0.125 mm thickness were irradiated at doses between 5 and 20 kGy in the presence of styrene/N,N-dimethylformamide (DMF), styrene/acetone or styrene/toluene solutions (1:1, v/v) at dose rate of 5 kGy h -1 by simultaneous method, using gamma rays from a Co-60, under nitrogen atmosphere and at room temperature. The films were characterized before and after modification by grafting yield (GY %), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM and EDS), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). GY results shows that grafting increases with dose and toluene hinders the grafting, leading to a small GY comparing to DMF and acetone. It was possible to confirm the grafting of styrene by FT-IR due to the new characteristics peaks and by the TG and DSC due to changes in thermal behavior of the grafted material. SEM and EDS show surface and cross-section distribution of the grafting, which takes place on the surface and heterogeneously with toluene as solvent and homogeneously and penetrating into the inner layers of the matrix using DMF and acetone as solvent. (author)

  8. Radiation induced degradation of dyes-An overview

    International Nuclear Information System (INIS)

    Rauf, M.A.; Ashraf, S. Salman

    2009-01-01

    Synthetic dyes are a major part of our life. Products ranging from clothes to leather accessories to furniture all depend on extensive use of organic dyes. An unfortunate side effect of extensive use of these chemicals is that huge amounts of these potentially carcinogenic compounds enter our water supplies. Various advanced oxidation processes (AOPs) including the use of high-energy radiation have been developed to degrade these compounds. In this review, dye decoloration and degradation as a result of its exposure to high energy radiation such as gamma radiation and pulsed electron beam are discussed in detail. The role of various transient species such as ·H, ·OH and e aq - are taken into account as reported by various researchers. Literature citations in this area show that e aq - is very effective in decolorization but is less active in the further degradation of the products formed. The degradation of the dyes is initiated exclusively by ·OH attack on electron-rich sites of the dye molecules. Additionally, various parameters that affect the efficiency of radiation induced degradation of dyes, such as effect of radiation dose, oxygen, pH, hydrogen peroxide, added ions and dye classes are also reviewed and summarized. Lastly, pilot plant application of radiation for wastewater treatment is briefly discussed.

  9. Radiation induced degradation of dyes--an overview.

    Science.gov (United States)

    Rauf, M A; Ashraf, S Salman

    2009-07-15

    Synthetic dyes are a major part of our life. Products ranging from clothes to leather accessories to furniture all depend on extensive use of organic dyes. An unfortunate side effect of extensive use of these chemicals is that huge amounts of these potentially carcinogenic compounds enter our water supplies. Various advanced oxidation processes (AOPs) including the use of high-energy radiation have been developed to degrade these compounds. In this review, dye decoloration and degradation as a result of its exposure to high energy radiation such as gamma radiation and pulsed electron beam are discussed in detail. The role of various transient species such as H, OH and e(aq)(-) are taken into account as reported by various researchers. Literature citations in this area show that e(aq)(-) is very effective in decolorization but is less active in the further degradation of the products formed. The degradation of the dyes is initiated exclusively by OH attack on electron-rich sites of the dye molecules. Additionally, various parameters that affect the efficiency of radiation induced degradation of dyes, such as effect of radiation dose, oxygen, pH, hydrogen peroxide, added ions and dye classes are also reviewed and summarized. Lastly, pilot plant application of radiation for wastewater treatment is briefly discussed.

  10. Radiation induced destruction of thebaine, papaverine and noscapine in methanol

    International Nuclear Information System (INIS)

    Kantoğlu, Ömer; Ergun, Ece

    2016-01-01

    The presence of methanol decreases the efficiency of radiation-induced decomposition of alkaloids in wastewater. Intermediate products were observed before the complete degradation of irradiated alkaloids. In order to identify the structure of the by-products and the formation pathway, thebaine, papaverine and noscapine solutions were prepared in pure methanol and irradiated using a 60 Co gamma cell at absorbed doses of 0, 1, 3, 5, 7, 10, 30, 50 and 80 kGy. The dose-dependent alkaloid degradation and by-product formation were monitored by ESI mass spectrometer. Molecular structures of the by-products and reaction pathways were proposed. Oxygenated and methoxy group containing organic compounds was observed in the mass spectra of irradiated alkaloids. At initial dose values oxygenated by-products were formed due to the presence of dissolved oxygen in solutions. After the consumption of dissolved oxygen with radicals, the main mechanism was addition of solvent radicals to alkaloid structure. However, it was determined that alkaloids and by-products were completely degraded at doses higher than 50 kGy. The G-value and degradation efficiency of alkaloids were also evaluated. - Highlights: • Oxygenated and methoxy group containing by-products were observed in the mass spectra. • The addition of methanol radiolysis products to alkaloid structure was suggested. • Intermediate products were decomposed at doses above 50 kGy. • The destruction efficiency and degradation G-value of alkaloids were calculated.

  11. Radiation-induced polymerization of some vinyl compounds

    International Nuclear Information System (INIS)

    Panta, P.; Gluszewski, W.; Zimek, Z.; Wojtynska, E.K.

    1998-01-01

    Complete text of publication follows. The action of accelerator electron beams (E.B.) and Co-60 gamma rays in inducing polymerization of monomers and oligomers of 2-ethylhexyl acrylate, acrylic acid and vinyl acetate was investigated. Using 10 MeV and 10 kW E.B. the time of free radical polymerization as short as several seconds was evaluated. The second order kinetics of polymerization reactions is proposed. Life times of free radicals generated during irradiation of 2-ethylhexyl acrylate, acrylic acid and vinyl acetate are very short at room temperature. For ESR measurements suitable samples were irradiated at 77 K and measured during defrosting. According to available literature data and own results the radiation-induced polymerization of above mentioned vinyl compounds is stopped during EB irradiation, without post effect. Besides polymerization of individual compounds we observe also mutual co-polymerization of appropriate mixtures of 2-ethylhexyl acrylate with acrylic acid and also vinyl acetate. Product of such co-polymerization exhibit some adhesive properties

  12. Perinatal radiation-induced renal damage in the beagle

    International Nuclear Information System (INIS)

    Jaenke, R.S.; Angleton, G.M.

    1990-01-01

    The developing perinatal kidney is particularly sensitive to radiation. The pathogenesis of the radiation-induced lesion is related to the destruction of outer cortical developing nephrons and direct radiation injury with secondary hemodynamic alterations in remnant nephrons. In this study, which is part of a life span investigation of the effects of whole-body gamma radiation during prenatal and early postnatal life, dogs were given 0, 0.16, 0.83, or 1.25 Gy irradiation at either 55 days postcoitus or 2 days postpartum and were examined morphometrically and histopathologically at 70 days of age. Although irradiated dogs showed no reduction in the total number of nephrons per kidney, there was a significant increase in the total number and relative percentage of immature, dysplastic glomeruli. In addition, deeper cortical glomeruli of irradiated kidneys exhibited mesangial sclerosis similar to that associated with progressive renal failure in our previous studies. These findings are in accord with those reported at doses of 2.24 to 3.57 Gy and demonstrate that the perinatal kidney is affected by radiation doses much lower than previously demonstrated

  13. Radiation induced oxidative damage modification by cholesterol in liposomal membrane

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Mishra, K.P. [Radiation Biology and Biochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    1999-05-01

    Ionizing radiation induced structural and chemical alterations in egg lecithin liposomal membrane have been studied by measurements of lipid peroxides, conjugated diene and fluorescence polarization. Predominantly unilamellar phospholipid vesicles prepared by sonication procedure were subjected to radiation doses of {gamma}-rays from Co-60 in aerated, buffered aqueous suspensions. The oxidative damage in irradiated lipid molecules of liposomes has been determined spectrophotometrically by diene conjugate formation and thiobarbituric acid reactive (TBAR) method as a function of radiation dose. A correlation was found between the radiation dose applied (0.1-1 kGy) and the consequent lipid oxidation. The damage produced in irradiated liposomal membrane was measured by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence decay and polarization. The observed decrease in DPH fluorescence and increase in polarization was found dependent on the radiation dose suggesting alterations in rigidity or organizational order in phospholipid bilayer after irradiation. Furthermore, irradiated liposome vesicles composed of cholesterol showed marked reduction in observed radiation mediated peroxide formation and significantly affected the DPH fluorescence parameters. The magnitude of these modifying effects were found dependent on the mole fraction of cholesterol. It is concluded that modulation of structural order in unilamellar vesicle membrane by variations in basic molecular components controlled the magnitude of lipid peroxidation and diene conjugate formation. These observations contribute to our understanding of mechanism of radical reaction mediated damage caused by ionizing radiation in phospholipid membrane.

  14. Transesophageal Echocardiography and Radiation-induced Damages.

    Science.gov (United States)

    Cottini, Marzia; Polizzi, Vincenzo; Pino, Paolo Giuseppe; Buffa, Vitaliano; Musumeci, Francesco

    2016-01-01

    The long-term sequelae of mantle therapy include, especially lung and cardiac disease but also involve the vessels and the organs in the neck and thorax (such as thyroid, aorta, and esophagus). We presented the case of 66-year-old female admitted for congestive heart failure in radiation-induced heart disease. The patient had undergone to massive radiotherapy 42 years ago for Hodgkin's disease (type 1A). Transesophageal echocardiography was performed unsuccessfully with difficulty because of the rigidity and impedance of esophageal walls. Our case is an extraordinary report of radiotherapy's latency effect as a result of dramatic changes in the structure of mediastinum, in particular in the esophagus, causing unavailability of a transesophageal echocardiogram.

  15. Radiation-induced emulsion polymerization of tetrafluoroethylene

    International Nuclear Information System (INIS)

    Suwa, Takeshi

    1979-10-01

    The radiation-induced emulsifier-free emulsion polymerization of tetrafluoroethylene (TFE) has been studied at initial pressure 2 - 25 kg/cm 2 and temperature 30 0 - 110 0 C for dose rate 0.57 x 10 4 - 3.0 x 10 4 rad/hr. Polytetrafluoroethylene (PTFE), a hydrophobic polymer, forms as a stable latex in the absence of an emulsifier. Stability of the latex is governed by the dose rate/TFE pressure ratio; it increases with sufficient TFE monomer. PTFE particles produced in this polymerization system are stable due to the carboxyl end groups and adsorption of OH - and HF on the particles. PTFE latex of molecular weight higher than 2 x 10 7 is obtained by addition of a radical scavenger such as hydroquinone. The molecular weight of PTFE can be measured from the heat of crystallization conveniently with high reliability, which was found in the course of study on the melting and crystallization behavior. (author)

  16. Radiation-induced premature menopause: a misconception

    International Nuclear Information System (INIS)

    Madsen, Berit L.; Giudice, Linda; Donaldson, Sarah S.

    1995-01-01

    Purpose: To disprove the common view that women who have undergone irradiation to fields excluding the pelvis are at risk for radiation-induced premature menopause, we reviewed menstrual function and fertility among women treated with subtotal lymphoid irradiation for Hodgkin's Disease. Methods and Materials: Treatment and follow-up records of all women less than age 50 at the time of diagnosis of Stage I or II supradiaphragmatic Hodgkin's Disease, treated with subtotal lymphoid irradiation alone and enrolled in radiotherapy trials from 1967 to 1985, were reviewed. In addition, patients were surveyed regarding their menstrual status and fertility history. Results: Thirty-six women, aged 10 to 40 years, with normal menstrual function at the time of Hodgkin's diagnosis, were identified. Mean follow-up was 14 years, with a range of 1.25-22.75 years. The average radiation dose to mantle and paraaortic fields was 40-44 Gy; the calculated scatter radiation dose to the pelvis at the ovaries was 3.2 Gy. There were 38 pregnancies in 18 women; all offspring are normal. One of 36 women (2.7%) experienced premature menopause. The reported rate of premature menopause in women who have not undergone irradiation is 1-3%; not significantly different than the rate in our study. There is a syndrome whereby antibodies to several endocrine organs occur (including the ovary), which is associated with premature ovarian failure. This syndrome may be associated with prior radiation to the thyroid, such as that given by mantle-irradiation for Hodgkin's Disease. We report such a case. Conclusion: There is little risk of premature menopause in women treated with radiation fields that exclude the pelvis. Women with presumed radiation-induced premature menopause warrant an evaluation to exclude other causes of ovarian failure, such as autoimmune disorders

  17. Conserved residues in the delta subunit help the E. coli clamp loader, gamma complex, target primer-template DNA for clamp assembly.

    Science.gov (United States)

    Chen, Siying; Coman, Maria Magdalena; Sakato, Miho; O'Donnell, Michael; Hingorani, Manju M

    2008-06-01

    The Escherichia coli clamp loader, gamma complex (gamma(3)deltadelta'lambdapsi), catalyzes ATP-driven assembly of beta clamps onto primer-template DNA (p/tDNA), enabling processive replication. The mechanism by which gamma complex targets p/tDNA for clamp assembly is not resolved. According to previous studies, charged/polar amino acids inside the clamp loader chamber interact with the double-stranded (ds) portion of p/tDNA. We find that dsDNA, not ssDNA, can trigger a burst of ATP hydrolysis by gamma complex and clamp assembly, but only at far higher concentrations than p/tDNA. Thus, contact between gamma complex and dsDNA is necessary and sufficient, but not optimal, for the reaction, and additional contacts with p/tDNA likely facilitate its selection as the optimal substrate for clamp assembly. We investigated whether a conserved sequence-HRVW(279)QNRR--in delta subunit contributes to such interactions, since Tryptophan-279 specifically cross-links to the primer-template junction. Mutation of delta-W279 weakens gamma complex binding to p/tDNA, hampering its ability to load clamps and promote proccessive DNA replication, and additional mutations in the sequence (delta-R277, delta-R283) worsen the interaction. These data reveal a novel location in the C-terminal domain of the E. coli clamp loader that contributes to DNA binding and helps define p/tDNA as the preferred substrate for the reaction.

  18. Dynamics of wound healing signaling as a potential therapeutic target for radiation-induced tissue damage.

    Science.gov (United States)

    Chung, Yih-Lin; Pui, Newman N M

    2015-01-01

    We hypothesized the histone deacetylase inhibitor phenylbutyrate (PB) has beneficial effects on radiation-induced injury by modulating the expression of DNA repair and wound healing genes. Hamsters received a radiosurgical dose of radiation (40 Gy) to the cheek and were treated with varying PB dosing regimens. Gross alteration of the irradiated cheeks, eating function, histological changes, and gene expression during the course of wound healing were compared between treatment groups. Pathological analysis showed decreased radiation-induced mucositis, facilitated epithelial cell growth, and preventing ulcerative wound formation, after short-term PB treatment, but not after vehicle or sustained PB. The radiation-induced wound healing gene expression profile exhibited a sequential transition from the inflammatory and DNA repair phases to the tissue remodeling phase in the vehicle group. Sustained PB treatment resulted in a prolonged wound healing gene expression profile and delayed the wound healing process. Short-term PB shortened the duration of inflammatory cytokine expression, triggered repeated pulsed expression of cell cycle and DNA repair-regulating genes, and promoted earlier oscillatory expression of tissue remodeling genes. Distinct gene expression patterns between sustained and short-term treatment suggest dynamic profiling of wound healing gene expression can be an important part of a biological therapeutic strategy to mitigate radiation-related tissue injury. © 2015 by the Wound Healing Society.

  19. Biological dosimetry: the potential use of radiation-induced apoptosis in human T-lymphocytes

    International Nuclear Information System (INIS)

    Menz, R.; Andres, R.; Larsson, B.; Ozsahin, M.; Crompton, N.E.A.; Trott, K.

    1997-01-01

    An assay for biological dosimetry based on the induction of apoptosis in human T-lymphocytes is described. Radiation-induced apoptosis was assessed by flow cytometric identification of cells displaying apoptosis-associated DNA condensation. CD4 and CD8 T-lymphocytes were analysed. They were recognized on the basis of their cell-surface antigens. Four parameters were measured for both cell types: cell size, granularity, antigen immunofluorescence and DNA content. Apoptosis was quantified as the fraction of CD4-, or CD8-positive cells with a characteristic reduction of cell size and DNA content. At doses below 1 Gy, levels of radiation-induced apoptosis increased for up to 5 days after irradiation. Optimal dose discrimination was observed 4 days after irradiation, at which time the dose-response curves were linear, with a slope of 8% ± 0.5% per 0.1 Gy. In controlled, dose-response experiments the lowest dose level at which the radiation-induced apoptosis frequency was still significantly above control was 0.05 Gy. After 5 days post-irradiation incubation, intra- and interdonor variations were measured and found to be similar; thus, apoptotic levels depend more on the dose than on the donor. The results demonstrate the potential of this assay as a biological dosimeter. (orig.)

  20. Changes in DNA base sequence induced by gamma-ray mutagenesis of lambda phage and prophage

    Energy Technology Data Exchange (ETDEWEB)

    Tindall, K.R.; Stein, J.; Hutchinson, F.

    1988-04-01

    Mutations in the cI (repressor) gene were induced by gamma-ray irradiation of lambda phage and of prophage, and 121 mutations were sequenced. Two-thirds of the mutations in irradiated phage assayed in recA host cells (no induction of the SOS response) were G:C to A:T transitions; it is hypothesized that these may arise during DNA replication from adenine mispairing with a cytosine product deaminated by irradiation. For irradiated phage assayed in host cells in which the SOS response had been induced, 85% of the mutations were base substitutions, and in 40 of the 41 base changes, a preexisting base pair had been replaced by an A:T pair; these might come from damaged bases acting as AP (apurinic or apyrimidinic) sites. The remaining mutations were 1 and 2 base deletions. In irradiated prophage, base change mutations involved the substitution of both A:T and of G:C pairs for the preexisting pairs; the substitution of G:C pairs shows that some base substitution mechanism acts on the cell genome but not on the phage. In the irradiated prophage, frameshifts and a significant number of gross rearrangements were also found.

  1. Isolation and characterization of cDNA clones for the gamma subunit of Xenopus fibrinogen, the product of a coordinately regulated gene family.

    Science.gov (United States)

    Bhattacharya, A; Shepard, A R; Moser, D R; Holland, L J

    1990-09-10

    Fibrinogen, the major structural protein involved in blood coagulation, is synthesized and secreted by the liver. In the frog Xenopus laevis, fibrinogen production is dramatically induced by glucocorticoids. The hormonal stimulation requires synthesis of three separate subunits, designated A alpha, B beta, and gamma. For investigation of the molecular mechanisms underlying this coordinate induction, we have isolated cDNA clones for the subunits of Xenopus fibrinogen. In this communication we describe the identification of clones for the gamma chain. Initially, a Xenopus liver cDNA library in pBR322 was screened with a rat gamma chain cDNA and a clone representing half of the 1600-base frog gamma mRNA was identified. This clone was shown to be complementary to gamma mRNA by hybrid selection of mRNA that translated in vitro into the gamma polypeptide. A clone about 1460 base pairs in length was then isolated from a Xenopus liver lambda gt10 cDNA library and subcloned into Bluescript SK-. This clone, designated X1 gamma 3, contains the entire 3'-end and lacks 38 bases at the 5'-end of gamma mRNA. The deduced amino acid sequence at the N-terminal is compatible with a signal peptide of 20-23 amino acids, in agreement with the calculated size of the frog gamma chain signal peptide. Following the signal sequence is a region of highly conserved amino acids that participate in disulfide bond formation critical for the maintenance of tertiary structure in mammalian fibrinogen. The gamma cDNA clone was used to measure gamma mRNA in purified Xenopus liver cells treated with glucocorticoids in primary culture.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. DNA damage in human lymphocytes due to synergistic interaction between ionizing radiation and pesticide

    International Nuclear Information System (INIS)

    Kim, J. K.; Lee, K. H.; Lee, B. H.; Chun, K. J.

    2001-01-01

    Biological risks may arise from the possibility of the synergistic interaction between harmful factors such as ionizing radiation and pesticide. The effect of pesticide on radiation-induced DNA damage in human in human blood lymphocytes was evaluated by the single cell gel electrophoresis (SCGE) assay. The lymphocytes, with or without pretreatment of the pesticide, were exposed to 2.0 Gy of gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in SCGE assay, showed an excellent dose-response relationship. The present study confirms that the pesticide has the cytotoxic effect on lymphocytes and that it interacts synergistically with ionizing radiationon DNA damage, as well

  3. Radiation induced changes in the airway - anaesthetic implications ...

    African Journals Online (AJOL)

    Radiation induced changes in the airway - anaesthetic implications: case report. Mallika Balakrishnan, Renju Kuriakose, Rachel Cherian Koshy. Abstract. Radiation induces a variety of changes in the airway that can potentially lead to difficult intubation. Osteoradionecrosis (ORN) of the mandible, a severe consequence of ...

  4. Radiation-induced xerostomia in a patient with nasopharyngeal ...

    African Journals Online (AJOL)

    OBJECTIVE: This study reports a case of radiation-induced xerstomia in a patient with nasopharyngeal cancer, to emphasize the need for prompt oral care to prevent untoward effects of xerostomia and to improve patients' quality of life. CASE REPORT: A 60 year old man diagnosed of radiation-induced xerostomia, after 6 ...

  5. Radiation induced diffusion as a method to protect surface

    International Nuclear Information System (INIS)

    Baumvol, I.J.R.

    1980-01-01

    Radiation induced diffusion forms a coating adeherent and without interface on the surface of metalic substrates. This coating improves the behaviour of metal to corrosion and abrasion. The effect of radiation induced diffusion of tin and calcium on pure iron surface is described and analyzed in this work. (author) [pt

  6. [Medical prevention and treatment of radiation-induced pulmonary complications].

    Science.gov (United States)

    Vallard, A; Rancoule, C; Le Floch, H; Guy, J-B; Espenel, S; Le Péchoux, C; Deutsch, É; Magné, N; Chargari, C

    2017-08-01

    Radiation-induced lung injuries mainly include the (acute or sub-acute) radiation pneumonitis, the lung fibrosis and the bronchiolitis obliterans organizing pneumonia (BOOP). The present review aims at describing the diagnostic process, the current physiopathological knowledge, and the available (non dosimetric) preventive and curative treatments. Radiation-induced lung injury is a diagnosis of exclusion, since clinical, radiological, or biological pathognomonic evidences do not exist. Investigations should necessarily include a thoracic high resolution CT-scan and lung function tests with a diffusing capacity of the lung for carbon monoxide. No treatment ever really showed efficacy to prevent acute radiation-induced lung injury, or to treat radiation-induced lung fibrosis. The most promising drugs in order to prevent radiation-induced lung injury are amifostine, angiotensin-converting-enzyme inhibitors and pentoxifylline. Inhibitors of collagen synthesis are currently tested at a pre-clinical stage to limit the radiation-induced lung fibrosis. Regarding available treatments of radiation-induced pneumonitis, corticoids can be considered the cornerstone. However, no standardized program or guidelines concerning the initial dose and the gradual tapering have been scientifically established. Alternative treatments can be prescribed, based on clinical cases reporting on the efficacy of immunosuppressive drugs. Such data highlight the major role of the lung dosimetric protection in order to efficiently prevent radiation-induced lung injury. Copyright © 2017 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  7. Preparation of monoclonal antibodies against radiation-induced protein

    International Nuclear Information System (INIS)

    Nozawa, R.; Tanaka, A.; Watanabe, H.; Kitayama, S.

    1992-01-01

    We obtained the 6 monoclonal antibodies against gamma-induced proteins of Deinococcus radiodurans, and these antibodies were designated as Mab-3F, 4B, 4D, 4F, 4G and 12G. Using these antibodies, we investigated the relations between gamma-induced proteins and other stress protein in strain R1, and the induction of proteins were compared among strain R1, resistant mutant (rec1) and radiosensitive mutant (rec30). We found new 6 proteins recognized by these monoclonal antibodies which were induced after gamma-irradiation especially in strain R1 and rec 1, but not induced in strain rec30. We suppose that these proteins participate in repair of DNA damages including double strand breaks caused by gamma-irradiation. One of them was around 46kDa protein band recognized by Mab-12G, and this protein was so induced in a large quantity after irradiation that the protein could detect by gold staining. In addition to this observation, we found some proteins which were induced in R1 and rec 1 by gamma-irradiation and other stress, but not in strain rec30, such as 31kDa protein band recognized by Mab-3F, 4B and 4G, and other 11 proteins which were especially induced in irradiated strain R1. The latter proteins might be reinforcement factor to radioresistance such as GroE and DnaK, or participant in repair of damage by gamma-irradiation in strain R1. (author)

  8. Radiation-induced bystander effects in cultured human stem cells.

    Directory of Open Access Journals (Sweden)

    Mykyta V Sokolov

    2010-12-01

    Full Text Available The radiation-induced "bystander effect" (RIBE was shown to occur in a number of experimental systems both in vitro and in vivo as a result of exposure to ionizing radiation (IR. RIBE manifests itself by intercellular communication from irradiated cells to non-irradiated cells which may cause DNA damage and eventual death in these bystander cells. It is known that human stem cells (hSC are ultimately involved in numerous crucial biological processes such as embryologic development; maintenance of normal homeostasis; aging; and aging-related pathologies such as cancerogenesis and other diseases. However, very little is known about radiation-induced bystander effect in hSC. To mechanistically interrogate RIBE responses and to gain novel insights into RIBE specifically in hSC compartment, both medium transfer and cell co-culture bystander protocols were employed.Human bone-marrow mesenchymal stem cells (hMSC and embryonic stem cells (hESC were irradiated with doses 0.2 Gy, 2 Gy and 10 Gy of X-rays, allowed to recover either for 1 hr or 24 hr. Then conditioned medium was collected and transferred to non-irradiated hSC for time course studies. In addition, irradiated hMSC were labeled with a vital CMRA dye and co-cultured with non-irradiated bystander hMSC. The medium transfer data showed no evidence for RIBE either in hMSC and hESC by the criteria of induction of DNA damage and for apoptotic cell death compared to non-irradiated cells (p>0.05. A lack of robust RIBE was also demonstrated in hMSC co-cultured with irradiated cells (p>0.05.These data indicate that hSC might not be susceptible to damaging effects of RIBE signaling compared to differentiated adult human somatic cells as shown previously. This finding could have profound implications in a field of radiation biology/oncology, in evaluating radiation risk of IR exposures, and for the safety and efficacy of hSC regenerative-based therapies.

  9. Radiation-induced cancer in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Shoji; Sekizuka, Eiichi [National Saitama Hospital, Wako (Japan); Yamashita, Hisao [Keio Cancer Center, Tokyo (Japan); Takami, Akira [Yamawaki Coll., Tokyo (Japan); Kubo, Atsushi [Keio Univ., Tokyo (Japan). School of Medicine

    2001-12-01

    Results of two questionnaire surveys on radiation-induced malignant tumors conducted in 1977 and 1984 in Japan are briefly summarized. A total of 234 universities and general hospitals (139 in 1977, and 95 in 1984) responded and provided data from 1945 to 1977 and from 1978 to 1984. The number of patients with benign disease who developed secondary malignant tumors following radiation therapy was 150 in the first survey (1977) and 86 in the second survey (1984). The underlying benign diseases of these patients included tuberculous lymphadenitis, skin disease, hemangioma, and thyroid disease, and the most frequent radiation-induced malignant tumors in these patients were malignant tumors of the pharynx (80), cancer of the larynx (26), malignant tumors of the thyroid gland (22), cancer of the esophagus (219), and skin cancer (21). In patients with head and neck diseases the highest correlation between underlying benign disease and radiation-induced malignant tumors was between cervical tuberculous lymphadenitis and tumors of the pharynx (67 patients), followed by cancer of the larynx (19), and malignant tumors of the thyroid gland (11). There were also correlations between thyroid disease and malignant tumors of the thyroid gland (8 patients), hemangioma and skin cancer (7), and skin disease and skin cancer (8). The ratio of the observed values to predicted values (O/E ratio) in these patients was highest for cancer of the pharynxy (118), followed by cancer of the parotid gland (42), skin cancer (31), cancer of the esophagus (22), malignant tumors of the thyroid gland (21), and cancer of the larynx (16). The number of patients with malignant tumors who developed secondary malignant tumors following radiation therapy was 140 in 1977 and 108 in 1984, and the underlying malignant tumors in these patients included tumors of the uterus (106), breast (32), and head and neck (80). The most frequent secondary malignant tumors were soft tissue tumors, followed by leukemia

  10. Radiation-induced cancer in Japan

    International Nuclear Information System (INIS)

    Yamashita, Shoji; Sekizuka, Eiichi; Yamashita, Hisao; Takami, Akira; Kubo, Atsushi

    2001-01-01

    Results of two questionnaire surveys on radiation-induced malignant tumors conducted in 1977 and 1984 in Japan are briefly summarized. A total of 234 universities and general hospitals (139 in 1977, and 95 in 1984) responded and provided data from 1945 to 1977 and from 1978 to 1984. The number of patients with benign disease who developed secondary malignant tumors following radiation therapy was 150 in the first survey (1977) and 86 in the second survey (1984). The underlying benign diseases of these patients included tuberculous lymphadenitis, skin disease, hemangioma, and thyroid disease, and the most frequent radiation-induced malignant tumors in these patients were malignant tumors of the pharynx (80), cancer of the larynx (26), malignant tumors of the thyroid gland (22), cancer of the esophagus (219), and skin cancer (21). In patients with head and neck diseases the highest correlation between underlying benign disease and radiation-induced malignant tumors was between cervical tuberculous lymphadenitis and tumors of the pharynx (67 patients), followed by cancer of the larynx (19), and malignant tumors of the thyroid gland (11). There were also correlations between thyroid disease and malignant tumors of the thyroid gland (8 patients), hemangioma and skin cancer (7), and skin disease and skin cancer (8). The ratio of the observed values to predicted values (O/E ratio) in these patients was highest for cancer of the pharynx (118), followed by cancer of the parotid gland (42), skin cancer (31), cancer of the esophagus (22), malignant tumors of the thyroid gland (21), and cancer of the larynx (16). The number of patients with malignant tumors who developed secondary malignant tumors following radiation therapy was 140 in 1977 and 108 in 1984, and the underlying malignant tumors in these patients included tumors of the uterus (106), breast (32), and head and neck (80). The most frequent secondary malignant tumors were soft tissue tumors, followed by leukemia, and

  11. Persistence of Gamma-H2AX Foci in Irradiated Bronchial Cells Correlates with Susceptibility to Radiation Associated Lung Cancer in Mice

    Science.gov (United States)

    Ochola, Donasian O.; Sharif, Rabab; Bedford, Joel S.; Keefe, Thomas J.; Kato, Takamitsu A.; Fallgren, Christina M.; Demant, Peter; Costes, Sylvain V.; Weil, Michael M.

    2018-01-01

    The risk of developing radiation-induced lung cancer differs between different strains of mice, but the underlying cause of the strain differences is unknown. Strains of mice also differ in their ability to efficiently repair DNA double strand breaks resulting from radiation exposure. We phenotyped mouse strains from the CcS/Dem recombinant congenic strain set for their efficacy in repairing DNA double strand breaks during protracted radiation exposures. We monitored persistent gamma-H2AX radiation induced foci (RIF) 24 hours after exposure to chronic gamma-rays as a surrogate marker for repair deficiency in bronchial epithelial cells for 17 of the CcS/Dem strains and the BALB/cHeN founder strain. We observed a very strong correlation R2 = 79.18%, P cancer percent incidence measured in the same strains. Interestingly, spontaneous levels of foci in non-irradiated strains also showed good correlation with lung cancer incidence (R2=32.74%, P =0.013). These results suggest that genetic differences in DNA repair capacity largely account for differing susceptibilities to radiation-induced lung cancer among CcS/Dem mouse strains and that high levels of spontaneous DNA damage is also a relatively good marker of cancer predisposition. In a smaller pilot study, we found that the repair capacity measured in peripheral blood leucocytes also correlated well with radiogenic lung cancer susceptibility, raising the possibility that such phenotyping assay could be used to detect radiogenic lung cancer susceptibility in humans.

  12. Radiation-induced apoptosis and developmental disturbance of the brain

    International Nuclear Information System (INIS)

    Inouye, Minoru

    1995-01-01

    The developing mammalian brain is highly susceptible to ionizing radiation. A significant increase in small head size and mental retardation has been noted in prenatally exposed survivors of the atomic bombing, with the highest risk in those exposed during 8-15 weeks after fertilization. This stage corresponds to day 13 of pregnancy for mice and day 15 for rats in terms of brain development. The initial damage produced by radiation at this stage is cell death in the ventricular zone (VZ) of the brain mantle, the radiosensitive germinal cell population. During histogenesis of the cerebellum the external granular layer (EGL) is also radiosensitive. Although extensive cell death results in microcephaly and histological abnormlity, both VZ and EGL have an ability to recover from a considerable cell loss and form the normal structure of the central nervous system. The number of cell deaths to induce tissue abnormalities in adult brain rises in the range of 15-25% of the germinal cell population; and the threshold doses are about 0.3 Gy for cerebral defects and 1 Gy for cerebellar anomalies in both mice and rats. A similar threshold level is suggested in human cases in induction of mental retardation. Radiation-induced cell death in the VZ and EGL has been revealed as apoptosis, by the nuclear and cytoplasmic condensation, transglutaminase activation, required macromolecular synthesis, and internucleosomal DNA cleavage. Apoptosis of the germinal cell is assumed to eliminate acquired genetic damage. Once an abnormality in DNA has been induced and fixed in a germinal cell, it would be greatly amplified during future proliferation. These cells would commit suicide when injured for replacement by healthy cells, rather than undertake DNA repair. In fact they show very slow repair of cellular damage. Thus the high sensitivity of undifferentiated neural cells to the lethal effect of radiation may constitute a biological defense mechanism. (author) 69 refs

  13. Laser radiation effect on radiation-induced defects in heavy ion tracks in dielectrics

    International Nuclear Information System (INIS)

    Egorov, A.N.; Zhiryakov, B.M.; Kushin, V.V.; Lyapidevskij, V.K.; Khokhlov, N.B.

    1988-01-01

    Possibility of laser radiation resonance effect on radiation-induced defects in heavy ion tracks in dielectric materials is investigated. Absorption spectra in infrared, visible and ultraviolet ranges for cellulose nitrate samples irradiated by 6 MeV/nucleon 58 Ni ions and reactor gamma radiation are measured. Absorption spectra for irradiated and reference samples are presented. Two absorption bands λ 1 =0.33 μm (E 1 =3.9 eV) and λ 2 =0.72 μm (E 2 =1.7 eV) are detected. Etching rate decrease in a track under laser radiation effect is noticed. 3 refs.; 1 fig

  14. Modification of radiation-induced oxidative damage in liposomal and microsomal membrane by eugenol

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, B.N. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Lathika, K.M. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Mishra, K.P. [Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)]. E-mail: kpm@magnum.barc.ernet.in

    2006-03-15

    Radiation-induced membrane oxidative damage, and their modification by eugenol, a natural antioxidant, was investigated in liposomes and microsomes. Liposomes prepared with DPH showed decrease in fluorescence after {gamma}-irradiation, which was prevented significantly by eugenol and correlated with magnitude of oxidation of phospholipids. Presence of eugenol resulted in substantial inhibition in MDA formation in irradiated liposomes/microsomes, which was less effective when added after irradiation. Similarly, the increase in phospholipase C activity observed after irradiation in microsomes was inhibited in samples pre-treated with eugenol. Results suggest association of radio- oxidative membrane damage with alterations in signaling molecules, and eugenol significantly prevented these membrane damaging events.

  15. Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)]. E-mail: krokosz@biol.uni.lodz.pl; Koziczak, Renata [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Gonciarz, Marta [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)

    2006-01-15

    Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with {gamma}-rays at three dose-rates of 66.7, 36.7, 25 Gy min{sup -1} in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect.

  16. Targets for, and consequences of, radiation-induced chromosomal instability

    Science.gov (United States)

    Kaplan, Mark Isaac

    Chromosomal instability has been demonstrated in a human- hamster hybrid cell line, GM10115, after exposure to x- rays. Chromosomal instability in these cells is characterized by the appearance of novel chromosomal rearrangements multiple generations after exposure to ionizing radiation. To identify the cellular target(s) for radiation-induced chromosomal instability, cells were treated with 125I-labeled compounds. Labeling cells with 125I-iododeoxyuridine, which caused radiation damage to the DNA and associated nuclear structures, did induce chromosomal instability. While cell killing and first-division chromosomal rearrangements increased with increasing numbers of 125I decays, the frequency of chromosomal instability was independent of dose. Incorporation of an 125I-labeled protein, 125I-succinyl- concanavalin A, into either the plasma membrane or the cytoplasm, failed to elicit chromosomal instability. These results show that radiation damage to the nucleus, and not to extranuclear regions, contributes to the induction of chromosomal instability. To determine the role of DNA strand breaks as a molecular lesion responsible for initiating chromosomal instability, cells were treated with a variety of DNA strand breaking agents. Agents capable of producing complex DNA double strand breaks, including X-rays, Neocarzinostatin and bleomycin, were able to induce chromosomal instability. In contrast, double strand breaks produced by restriction endonucleases as well as DNA strand breaks produced by hydrogen peroxide failed to induce chromosomal instability. This demonstrates that the type of DNA breakage is important in the eventual manifestation of chromosomal instability. In order to understand the relationship between chromosomal instability and other end points of genomic instability, chromosomally stable and unstable clones were analyzed for sister chromatid exchange, delayed reproductive cell death, delayed mutation, mismatch repair and delayed gene amplification

  17. Ionizing radiation induces stemness in cancer cells.

    Directory of Open Access Journals (Sweden)

    Laura Ghisolfi

    Full Text Available The cancer stem cell (CSC model posits the presence of a small number of CSCs in the heterogeneous cancer cell population that are ultimately responsible for tumor initiation, as well as cancer recurrence and metastasis. CSCs have been isolated from a variety of human cancers and are able to generate a hierarchical and heterogeneous cancer cell population. CSCs are also resistant to conventional chemo- and radio-therapies. Here we report that ionizing radiation can induce stem cell-like properties in heterogeneous cancer cells. Exposure of non-stem cancer cells to ionizing radiation enhanced spherogenesis, and this was accompanied by upregulation of the pluripotency genes Sox2 and Oct3/4. Knockdown of Sox2 or Oct3/4 inhibited radiation-induced spherogenesis and increased cellular sensitivity to radiation. These data demonstrate that ionizing radiation can activate stemness pathways in heterogeneous cancer cells, resulting in the enrichment of a CSC subpopulation with higher resistance to radiotherapy.

  18. Operative treatment of radiation-induced fistulae

    International Nuclear Information System (INIS)

    Balslev, I.; Harling, H.

    1987-01-01

    Out of 136 patients with radiation-induced intestinal complications, 45 had fistulae. Twenty-eight patients had rectovaginal fistulae while the remainder had a total of 13 different types of fistulae. Thirty-seven patients were treated operatively and eight were treated conservatively. Thirty-three patients were submitted to operation for rectal fistulae. Of these, 28 were treated by defunctioning colostomy, three were treated by Hartmann's method and resection and primary anastomosis was carried out in two patients. In the course of the period of observation, 35% of the patients developed new radiation damage. The frequency in the basic material without fistulae was 21% (0.05< p<0.10). Following establishment of defunctioning colostomy on account of rectovaginal fistulae in 25 patients, eight patients developed new fistulae, Significantly more patients with fistulae died of recurrence as compared with patients with other lesions (p<0.01). Defunctioning colostomy in the treatment of rectal fistula is a reasonable form of treatment in elderly patients and in case of recurrence. Younger patients should be assessed in a special department in view of the possibility of a sphincter-preserving procedure following resection of the rectum and restorative anastomosis. (author)

  19. Operative treatment of radiation-induced fistulae

    Energy Technology Data Exchange (ETDEWEB)

    Balslev, I.; Harling, H.

    1987-01-01

    Out of 136 patients with radiation-induced intestinal complications, 45 had fistulae. Twenty-eight patients had rectovaginal fistulae while the remainder had a total of 13 different types of fistulae. Thirty-seven patients were treated operatively and eight were treated conservatively. Thirty-three patients were submitted to operation for rectal fistulae. Of these, 28 were treated by defunctioning colostomy, three were treated by Hartmann's method and resection and primary anastomosis was carried out in two patients. In the course of the period of observation, 35% of the patients developed new radiation damage. The frequency in the basic material without fistulae was 21% (0.05

  20. Pathology of radiation induced lung damage

    International Nuclear Information System (INIS)

    Kawabata, Yoshinori; Murata, Yoshihiko; Ogata, Hideo; Katagiri, Shiro; Sugita, Hironobu; Iwai, Kazuo; Sakurai, Isamu.

    1985-01-01

    We examined pathological findings of radiation induced lung damage. Twenty-three cases are chosen from our hospital autopsy cases for 9 years, which fulfil strict criteria of radiation lung damage. Lung damage could be classified into 3 groups : 1) interstitial pneumonia type (9 cases), 2) intermediate pneumonia type (8 cases), and 3) alveolar pneumonia type (6 cases), according to the degree of intra-luminal exudation. These classification is well correlated with clinical findings. Pathological alveolar pneumonia type corresponds to symptomatic, radiologic ground glass pneumonic shadow. And pathologic interstitial type corresponds to clinical asymptomatic, radiologic reticulo-nodular shadow. From the clinico-pathological view point these classification is reasonable one. Radiation affects many lung structures and showed characteristic feature of repair. Elastofibrosis of the alveolar wall is observed in every cases, obstructive bronchiolitis are observed in 5 cases, and obstructive bronchiolitis in 9 cases. They are remarkable additional findings. Thickening of the interlobular septum, broncho-vascular connective tissue, and pleural layer are observed in every cases together with vascular lesions. (author)

  1. Radiation-induced ηe-modes

    International Nuclear Information System (INIS)

    Shukla, P.K.; Yu, M.Y.

    1990-01-01

    Impurity radiation in a plasma can cause not only static instabilities, but also dynamic instabilities related to the drift and acoustic waves. Radiative instabilities are of much interest because they are associated with relatively high frequency and short wavelength fluctuations, which have been suspected to be responsible for anomalous electron energy transport in tokamak edge plasmas. In this paper, we consider radiation-induced η e instabilities, taking into account electrostatic effects as well as density and temperature inhomogeneities. Also included are the effects of finite gyroradius and dissipation. It is found that the latter can cause strong linear coupling between the modes of interest. The resulting instabilities can have larger growth rates than the static radiative instability. Analytical expressions for the growth rates and instability regimes are given for the limiting cases of practical interest. In particular, it is shown that the η e -mode can couple to both radiation and dissipation to cause resistive instabilities. The parameter regimes of the original radiative as well as the dissipative modes are thereby broadened and shifted because of the interaction. (author) 3 refs

  2. Anti-inflammatory effects of tanshinone IIA on radiation-induced microglia BV-2 cells inflammatory response

    DEFF Research Database (Denmark)

    Dong, Xiaorong; Dong, Jihua; Zhang, Ruiguang

    2009-01-01

    and confocal microscopy analysis were applied to detect the expression of gamma-H2AX and p65 postirradiation. RESULTS: Radiation-induced release of proinflammatory cytokines in BV-2 cells was detectable after irradiation. Tanshinone II(A) decreased the radiation-induced release of proinflammatory cytokines......AIM: The aim of this study was to explore the inhibitory effects of Tanshinone II(A) on the production of proinflammation cytokines in radiation-stimulated microglia. METHODS: Microglia cells were treated with 2, 4, 8, 16, and 32 Gy of irradiation or sham-irradiated in the presence or absence of 1....... Further, Western blotting showed that Tanshinone II(A) could attenuate the nuclear translocation of (NF-kappabeta) p65 submit postirradiation. Immunofluorescence staining showed gamma-H2AX foci formation with p65 translocation into the nucleus postirradiation. CONCLUSIONS: Our data indicated...

  3. Botanical Extracts as Medical Countermeasures for Radiation Induced DNA Damage

    Science.gov (United States)

    2012-03-01

    TR 2012-05 35 [39] Owen, P.L., Johns, T. (1999) Xanthine oxidase inhibitory activity of northeastern North American plant remedies used for...3A4) A member of the cytochrome P450 mixed-function oxidase system, is one of the most important enzymes involved in the metabolism of xenobiotics

  4. Epigenetic Analysis of Heavy-ion Radiation Induced Bystander Effects in Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Cui, Changna; Xue, Bei

    Abstract: Radiation-induced bystander effect was defined as the induction of damage in neighboring non-hit cells by signals released from directly-irradiated cells. Recently, low dose of high LET radiation induced bystander effects in vivo have been reported more and more. It has been indicated that radiation induced bystander effect was localized not only in bystander tissues but also in distant organs. Genomic, epigenetic and proteomics plays significant roles in regulating heavy-ion radiation stress responses in mice. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male Balb/c and C57BL mice were exposed head-only to 40, 200, 2000mGy dose of (12) C heavy-ion radiation, while the rest of the animal body was shielded. Directly radiation organ ear and the distant organ liver were detected on 1h, 6h, 12h and 24h after radiation, respectively. Methylation-sensitive amplification polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that heavy-ion irradiated mouse head could induce genomic DNA methylation changes significantly in both the directly radiation organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate was highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation. The global DNA methylation changes tended to occur in the CG sites. The results illustrated that genomic methylation changes of heavy ion radiation-induced bystander effect in liver could be obvious 1 h after radiation and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in both directly radiation organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of

  5. Radiation induced lung injury: prediction, assessment and management.

    Science.gov (United States)

    Giridhar, Prashanth; Mallick, Supriya; Rath, Goura Kishore; Julka, Pramod Kumar

    2015-01-01

    Radiation induced lung injury has long been considered a treatment limiting factor for patients requiring thoracic radiation. This radiation induced lung injury happens early as well as late. Radiation induced lung injury can occur in two phases viz. early (radiation pneumonitis and late (>6 months) when it is called radiation induced lung fibrosis. There are multiple factors that can be patient, disease or treatment related that predict the incidence and severity of radiation pneumonitis. Radiation induced damage to the type I pneumocytes is the triggering factor to initiate such reactions. Over the years, radiation therapy has witnessed a paradigm shift in radiation planning and delivery and successfully reduced the incidence of lung injury. Radiation pneumonitis is usually a diagnosis of exclusion. Steroids, ACE inhibitors and pentoxyphylline constitute the cornerstone of therapy. Radiation induced lung fibrosis is another challenging aspect. The pathophysiology of radiation fibrosis includes continuing inflammation and microvascular changes due to pro-angiogenic and pro- fibrogenic stimuli resembling those in adult bronchiectasis. General supportive management, mobilization of airway secretions, anti-inflammatory therapy and management of acute exacerbations remains the treatment option. Radiation induced lung injury is an inevitable accompaniment of thoracic radiation.

  6. Preparation of Cellulosic Membrane Containing Pyrrolidone Moiety Via Radiation Induced Grafting and its Application in Wastewater Treatment

    OpenAIRE

    A. S. Aly; H. H. Sokker; A. Hashem; A. Hebeish

    2005-01-01

    Radiation induced grafting of vinyl pyrrolidone onto cellulose wood pulp was carried out in heterogeneous and homogenous media using gamma radiation. Cellulose wood pulp was used in different forms; a) in a homogenous solution by dissolving the wood pulp in N,N- dimethylacetamide/Lithium chloride (DMAc/LiCl) mixture , b) in a membrane form, by precipitating the cellulose solution in water and c) in a powder form. Factors affecting on the grafting such as radiation dos...

  7. Radiation-Induced Alopecia after Endovascular Embolization under Fluoroscopy

    Directory of Open Access Journals (Sweden)

    Vipawee Ounsakul

    2016-01-01

    Full Text Available Radiation-induced alopecia after fluoroscopically guided procedures is becoming more common due to an increasing use of endovascular procedures. It is characterized by geometric shapes of nonscarring alopecia related to the area of radiation. We report a case of a 46-year-old man presenting with asymptomatic, sharply demarcated rectangular, nonscarring alopecic patch on the occipital scalp following cerebral angiography with fistula embolization under fluoroscopy. His presentations were compatible with radiation-induced alopecia. Herein, we also report a novel scalp dermoscopic finding of blue-grey dots in a target pattern around yellow dots and follicles, which we detected in the lesion of radiation-induced alopecia.

  8. A case of radiation induced cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, Kazuyoshi; Tsuchikawa, Kohzo; Sato, Akira; Kato, Joji (Nippon Dental Univ., Niigata (Japan). School of Dentistry at Niigata)

    1994-06-01

    A case of carcinoma on the right buccal mucosa is presented. The case was suspected to have been induced by irradiation therapy for a carcinoma on the left buccal mucosa. An external radiotherapy, 6-MeV Linac, had been done for the carcinoma on the left buccal mucosa in a 55-year-old female, with single lateral direction from the left to the right in 1977. In 1985, a papillary lesion on the right buccal mucosa was detected, and histological examination revealed a papilloma without atypism. In 1991, as an ulcer on the right upper buccal fold as well as three papillary lesions in the central portion of the right buccal mucosa were found, the patient was referred to our clinic. Microscopical findings were consistent with the early invasive carcinomas. A surgical excision of these whole lesions and skin graft were completed. The criteria of this case for the suspicion of radiation-induced carcinoma were as follows. There was a long latent period of 14 years. The previous dose of irradiation, 60 Gy, was sufficient. The right buccal mucosa was involved in the radiation field. A severe scar on the left cheek resulted from the previous irradiation. Anatomically, there is no evidence of the secondary carcinoma on the right buccal mucosa with the primary carcinoma on the left buccal mucosa. No evidence for recurrence of the tumors on both sides of buccal mucosa has been detected so far. Further observations will be necessary to detect other tumors in the irradiated field later on. (author).

  9. Radiation-induced carotid artery atherosclerosis

    International Nuclear Information System (INIS)

    Gujral, Dorothy M.; Chahal, Navtej; Senior, Roxy; Harrington, Kevin J.; Nutting, Christopher M.

    2014-01-01

    Purpose: Carotid arteries frequently receive significant doses of radiation as collateral structures in the treatment of malignant diseases. Vascular injury following treatment may result in carotid artery stenosis (CAS) and increased risk of stroke and transient ischaemic attack (TIA). This systematic review examines the effect of radiotherapy (RT) on the carotid arteries, looking at the incidence of stroke in patients receiving neck radiotherapy. In addition, we consider possible surrogate endpoints such as CAS and carotid intima-medial thickness (CIMT) and summarise the evidence for radiation-induced carotid atherosclerosis. Materials and methods: From 853 references, 34 articles met the criteria for inclusion in this systematic review. These papers described 9 studies investigating the incidence of stroke/TIA in irradiated patients, 11 looking at CAS, and 14 examining CIMT. Results: The majority of studies utilised suboptimally-matched controls for each endpoint. The relative risk of stroke in irradiated patients ranged from 1.12 in patients with breast cancer to 5.6 in patients treated for head and neck cancer. The prevalence of CAS was increased by 16–55%, with the more modest increase seen in a study using matched controls. CIMT was increased in irradiated carotid arteries by 18–40%. Only two matched-control studies demonstrated a significant increase in CIMT of 36% and 22% (p = 0.003 and <0.001, respectively). Early prospective data demonstrated a significant increase in CIMT in irradiated arteries at 1 and 2 years after RT (p < 0.001 and <0.01, respectively). Conclusions: The incidence of stroke was significantly increased in patients receiving RT to the neck. There was a consistent difference in CAS and CIMT between irradiated and unirradiated carotid arteries. Future studies should optimise control groups

  10. The profiles of gamma-H2AX along with ATM/DNA-PKcs activation in the lymphocytes and granulocytes of rat and human blood exposed to gamma rays

    International Nuclear Information System (INIS)

    Wang, Jing; Yin, Lina; Zhang, Junxiang; Zhang, Yaping; Zhang, Xuxia; Ding, Defang; Gao, Yun; Li, Qiang; Chen, Honghong

    2016-01-01

    Establishing a rat model suitable for γ-H2AX biodosimeter studies has important implications for dose assessment of internal radionuclide contamination in humans. In this study, γ-H2AX, p-ATM and p-DNA-PKcs foci were enumerated using immunocytofluorescence method, and their protein levels were measured by Western blot in rat blood lymphocytes and granulocytes exposed to γ-rays compared with human blood lymphocytes and granulocytes. It was found that DNA double-strand break repair kinetics and linear dose responses in rat lymphocytes were similar to those observed in the human counterparts. Moreover, radiation induced clear p-ATM and p-DNA-PKcs foci formation and an increase in ratio of co-localization of p-ATM or p-DNA-PKcs with γ-H2AX foci in rat lymphocytes similar to those of human lymphocytes. The level of γ-H2AX protein in irradiated rat and human lymphocytes was significantly reduced by inhibitors of ATM and DNA-PKcs. Surprisingly, unlike human granulocytes, rat granulocytes with DNA-PKcs deficiency displayed a rapid accumulation, but delayed disappearance of γ-H2AX foci with essentially no change from 10 h to 48 h post-irradiation. Furthermore, inhibition of ATM activity in rat granulocytes also decreased radiation-induced γ-H2AX foci formation. In comparison, human granulocytes showed no response to irradiation regarding γ-H2AX, p-ATM or p-DNA-PKcs foci. Importantly, incidence of γ-H2AX foci in lymphocytes after total-body radiation of rats was consistent with that of in vitro irradiation of rat lymphocytes. These findings show that rats are a useful in vivo model for validation of γ-H2AX biodosimetry for dose assessment in humans. ATM and DNA-PKcs participate together in DSB repair in rat lymphocytes similar to that of human lymphocytes. Further, rat granulocytes, which have the characteristic of delayed disappearance of γ-H2AX foci in response to radiation, may be a useful experimental system for biodosimetry studies. (orig.)

  11. The profiles of gamma-H2AX along with ATM/DNA-PKcs activation in the lymphocytes and granulocytes of rat and human blood exposed to gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Yin, Lina; Zhang, Junxiang; Zhang, Yaping; Zhang, Xuxia; Ding, Defang; Gao, Yun; Li, Qiang; Chen, Honghong [Fudan University, Department of Radiation Biology, Institute of Radiation Medicine, Shanghai (China)

    2016-08-15

    Establishing a rat model suitable for γ-H2AX biodosimeter studies has important implications for dose assessment of internal radionuclide contamination in humans. In this study, γ-H2AX, p-ATM and p-DNA-PKcs foci were enumerated using immunocytofluorescence method, and their protein levels were measured by Western blot in rat blood lymphocytes and granulocytes exposed to γ-rays compared with human blood lymphocytes and granulocytes. It was found that DNA double-strand break repair kinetics and linear dose responses in rat lymphocytes were similar to those observed in the human counterparts. Moreover, radiation induced clear p-ATM and p-DNA-PKcs foci formation and an increase in ratio of co-localization of p-ATM or p-DNA-PKcs with γ-H2AX foci in rat lymphocytes similar to those of human lymphocytes. The level of γ-H2AX protein in irradiated rat and human lymphocytes was significantly reduced by inhibitors of ATM and DNA-PKcs. Surprisingly, unlike human granulocytes, rat granulocytes with DNA-PKcs deficiency displayed a rapid accumulation, but delayed disappearance of γ-H2AX foci with essentially no change from 10 h to 48 h post-irradiation. Furthermore, inhibition of ATM activity in rat granulocytes also decreased radiation-induced γ-H2AX foci formation. In comparison, human granulocytes showed no response to irradiation regarding γ-H2AX, p-ATM or p-DNA-PKcs foci. Importantly, incidence of γ-H2AX foci in lymphocytes after total-body radiation of rats was consistent with that of in vitro irradiation of rat lymphocytes. These findings show that rats are a useful in vivo model for validation of γ-H2AX biodosimetry for dose assessment in humans. ATM and DNA-PKcs participate together in DSB repair in rat lymphocytes similar to that of human lymphocytes. Further, rat granulocytes, which have the characteristic of delayed disappearance of γ-H2AX foci in response to radiation, may be a useful experimental system for biodosimetry studies. (orig.)

  12. Multiple factors participating in radiation-induced adaptive response

    International Nuclear Information System (INIS)

    Nenoi, Mitsuru; Vares, G.; Wang, Bing

    2009-01-01

    Radiation-induced adaptive response (RAR) is essentially the acquisition of radiation resistance by pre-exposed low dose radiation (priming). In this paper, in vitro findings on RAR-related factors are reviewed and authors' studies of RAR-related gene analysis in lethality and malformation of mouse fetus are described for future view. Studies on in vitro RAR have involved such participating factors as signal transduction, response appearance and bystander effect, and gene expression profiling. In RAR, DNA double strand break (DSB) by priming is conceivably the initial stimulation. In various cell systems including p53-knockout cells and in enzyme inhibition studies, intracellular signaling factors like protein kinase C, p38 MAPK, phospholipase C have been shown to participate. Increased activities of antioxidant and of damaged DNA repairing system, modulation of cell cycle, heat-shock reactions and apoptosis are suggested to concern to RAR appearance. Relationship between RAR and bystander effect is conceived to be important based on findings of cell lethality, mutagenesis, gap junction and NO radical. Genes relating to DSB repair, stress response, cell cycle and apoptosis have been shown to be specifically changed in RAR by their expression profile. Authors have conducted in vivo studies on RAR using embryogenetic system in the mouse. They have shown by gene profiling that signaling evoked by priming is important when the fetal lethality and malformation are used as RAR measures, and that in the subsequent process to RAR appearance, many signaling factors, particularly the transcription factor like p53, play a role. Database construction according to measures employed in individual studies, classification of living systems studied, radiation factors like linear energy transfer (LET), dose and dose rate, and functional genes concerned is thought useful for understanding the ultimate molecular mechanisms involved in ARA. (K.T.)

  13. Hazard of the radiation induced thyroid cancer

    International Nuclear Information System (INIS)

    Buglova, Ye.Ye.

    2001-01-01

    The level of thyroid cancer in Belarus before Chernobyl accident was low and made in different age and sex groups 0,03-2,5 (male) and 0,1-3,9 (female) per 100000 correspondingly. Different risk factors, which can influence the thyroid cancer development, are being taken into account. They are the factors of environment (strong external irradiation, long-time irradiation for medical purposes or in result of disaster), endo gen factors (hormonal, reproductive, genetic predisposition), some medicinal preparations and other. The protective effect of vegetable and fish consumption was found out. Among the factors of thyroid cancer development one of the most important is radiation. There is a point of view, which assumes that one of the reasons of thyroid cancer cases increase among the population of developed countries is increase of radiation induced thyroid cancer. The results of first research testify the influence of radiation factor on thyroid cancer development. During the period 1920 -1960 in the USA X-ray therapy was applied for the treatment of different good-quality diseases. Thyroid got in the zone of irradiation during the complex treatment with using of radiation. The results of the research of 1970 revealed that 70% of children with thyroid cancer were exposed to radiation in children's age. The subsequent researches of by-effects from the side of a thyroid at beam therapy of various diseases alongside with the results of the estimation of consequences of inhabitants of Hiroshima and Nagasaki irradiation owing to nuclear bombardment have shown the influence of irradiation of a thyroid on cancer development. High quantity of radio-epidemiological researches was directed to the studying of the consequences of thyroid external irradiation at young age. In all carried out researches the quantity of observed thyroid cancer cases among irradiated people has exceeded number of expected. The influence of thyroid internal irradiation by I-131 at young age was

  14. Cloning of laminin gamma2 cDNA and chromosome mapping of the genes for the dog adhesion ligand laminin 5.

    Science.gov (United States)

    Capt, Annabelle; Spirito, Flavia; Guyon, Richard; André, Catherine; Ortonne, Jean-Paul; Meneguzzi, Guerrino

    2003-12-26

    Overexpression of the gamma2 chain of laminin-5 has been linked to tumor invasion and an unfavorable prognostic value, but the role of this adhesion molecule in cancer progression remains unclear. Because dog models of human cancers provide the opportunity of clarifying the relation between laminin-5 and tumor malignancy we have isolated and characterized the cDNA of dog gamma2 chain. Comparative analysis of the nucleotide sequence revealed high identity between the dog and the human gamma2, including the intermolecular molecule binding sites and the regulatory promoter sequences. Moreover, expression of a recombinant human gamma2 chain in dog keratinocytes results in assembly and secretion of hybrid laminin-5 molecules, which underscore the functional relevance of the gamma2 conserved domains. We have also determined the syntenic location of the dog laminin-5 loci on CFA7. Our study provides a basis for therapeutical approaches of epithelial cancers of gamma2 using dogs as large animal models.

  15. Arabidopsis DNA ligase IV is induced by gamma-irradiation and interacts with an Arabidopsis homologue of the double strand break repair protein XRCC4.

    Science.gov (United States)

    West, C E; Waterworth, W M; Jiang, Q; Bray, C M

    2000-10-01

    Rejoining of single- and double-strand breaks (DSBs) introduced in DNA during replication, recombination, and DNA damage is catalysed by DNA ligase enzymes. Eukaryotes possess multiple DNA ligase enzymes, each having distinct roles in cellular metabolism. Double-strand breaks in DNA, which can occur spontaneously in the cell or be induced experimentally by gamma-irradiation, represent one of the most serious threats to genomic integrity. Non-homologous end joining (NHEJ) rather than homologous recombination is the major pathway for repair of DSBs in organisms with complex genomes, including humans and plants. DNA ligase IV in Saccharomyces cerevisiae and humans catalyses the final step in the NHEJ pathway of DSB repair. In this study we identify an Arabidopsis thaliana homologue (AtLIG4) of human and S. cerevisiae DNA ligase IV which is shown to encode an ATP-dependent DNA ligase with a theoretical molecular mass of 138 kDa and 48% similarity in amino-acid sequence to the human DNA ligase IV. Yeast two-hybrid analysis demonstrated a strong interaction between A. thaliana DNA ligase IV and the A. thaliana homologue of the human DNA ligase IV-binding protein XRCC4. This interaction is shown to be mediated via the tandem BRCA C-terminal domains of A. thaliana DNA ligase IV protein. Expression of AtLIG4 is induced by gamma-irradiation but not by UVB irradiation, consistent with an in vivo role for the A. thaliana DNA ligase IV in DSB repair.

  16. Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

    International Nuclear Information System (INIS)

    Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R.

    1996-01-01

    Exposure of rats to 5-10 Gy of ionizing radiation produces hyperthermia and reduces motor activity. Previous studies suggested that radiation-induced hyperthermia results from a relatively direct action on the brain and is mediated by prostaglandins. To test the hypothesis that hypoactivity may be, in part, a thermoregulatory response to this elevation in body temperature, adult male rats were given indomethacin (0.0, 0.5, 1.0, and 3.0 mg/kg, intraperitoneally), a blocker of prostaglandin synthesis, and were either irradiated (LINAC 18.6 MeV (nominal) high-energy electrons, 10 Gy at 10 Gy/min, 2.8 μsec pulses at 2 Hz) or sham-irradiated. The locomotor activity of all rats was then measured for 30 min in a photocell monitor for distance traveled and number of vertical movements. Rectal temperatures of irradiated rats administered vehicle only were elevated by 0.9±0.2degC at the beginning and the end of the activity session. Although indomethacin, at the two higher doses tested, attenuated the hyperthermia in irradiated rats by 52-75%, it did not attenuate radiation-induced reductions in motor activity. These results indicate that motor hypoactivity after exposure to 10 Gy of high-energy electrons is not due to elevated body temperature or to the increased synthesis of prostaglandins. (author)

  17. Radiation induced early maturing mutants in barley

    International Nuclear Information System (INIS)

    Kumar, R.; Chauhan, S.V.S.; Sharma, R.P.

    1978-01-01

    In M 2 generation, two early maturing plants were screened from a single spike progeny of a plant obtained from 20 kR of gamma-ray irradiation of a six-rowed barley (Hordeum vulgare L. var. Jyoti). Their true breeding nature was confirmed in M 3 generation. These mutants flower and mature 38 and 22 days earlier than those of control. (auth.)

  18. Image Guidance and Assessment of Radiation Induced Gene Therapy

    National Research Council Canada - National Science Library

    Pelizzari, Charles

    2004-01-01

    Image guidance and assessment techniques are being developed for combined radiation/gene therapy, which utilizes a radiation-inducible gene promoter to cause expression of tumor necrosis factor alpha...

  19. Characterization of a Novel Radiation-Induced Sarcoma Cell Line

    Czech Academy of Sciences Publication Activity Database

    Lang, J.; Zhu, W.Z.; Nokes, B.; Sheth, S.G.; Novák, Petr; Fuchs, L.; Watts, G.; Futscher, B. W.; Mineyev, N.; Ring, A.

    2015-01-01

    Roč. 111, č. 6 (2015), s. 669-682 ISSN 0022-4790 Institutional support: RVO:60077344 Keywords : Sarcoma * radiation-induced * breast * cancer Subject RIV: FD - Oncology ; Hematology Impact factor: 3.151, year: 2015

  20. Physical mechanisms of radiation induced creep in metals

    International Nuclear Information System (INIS)

    Borodin, V.A.; Ryazanov, A.I.

    1990-01-01

    Analysis of available experimental data has been conducted. It enables to correlate reliably the character of evolution of dislocation structure of irradiated materials with different stages of radiation induced creep. This provides reliable basis for the general conclusions concerning the character of some parametric dependences of deformation rate of these materials. Analysis of different modern theoretical models enables to evaluate regions of their applicability and their relative significance for radiation induced creep description. 20 refs.; 2 figs.; 1 tab

  1. Grape Seed Oil Extract Protects Against Radiation-Induced Oxidative Damage in Rats Eyes

    International Nuclear Information System (INIS)

    Naguib, N.I.

    2011-01-01

    The present study was carried out to investigate the beneficial effects of grape seed oil on radiation-induced oxidative stress in the irradiated rat eyes. The rats were divided into three groups; control group that received distilled water, irradiated group (R) that exposed to gamma radiation as a single dose of 6.4 Gy and irradiated + grape seed oil group (R+GSO) that administered grape seed oil for seven consecutive days then exposed to the same single gamma radiation dose followed by grape seed oil for seven additional days. Histopathological results revealed protective effect of grape seed oil on the eye tissues of rat. The results lead to the conclusion that administration of GSO prior to radiation exposure may be a promising attempt in attenuating the extent of oxidative damage accompanying radiotherapy

  2. A study on the improvement of radiation-induced oxidation resistance for polypropylene and PVC materials

    International Nuclear Information System (INIS)

    Park, K. Z.; Jeong, K. S.; Cho, S. H.; Cho, Y. H.; Seok, H. C.

    2002-01-01

    The object of this project is to improve the stability and the economics by reducing the radiation-induced oxidation as a factor of degradation of polymer materials used under the radiation environment. In order to attain the objective of this study and to check the effect of diamond-like carbon (DLC) coating on the anti-oxidation reaction, polymer specimens such as Polyproplyene, PVC coating DLC thin layer were exposed to high level gamma radiation, and their irradiation effects were investigated. A plasma-enhanced chemical vapor deposition method was adopted in fabricating a DLC thin film on the polymer specimens, which were irradiated with the non-DLC film deposited specimens under the gamma radiation emitted from Co-60 source from 1 x 10 5 to 1 x 10 8 rads exposure. According to the characterization of irradiated specimens from the elapsed time of minimum 4 hours to a maximum of 105 days after the irradiation, the DLC deposition on the polymer surface was revealed to contribute to the improvement on the resistance of the radiation-induced oxidation in this study

  3. Comparison of DNA comet assay and germination test (half-embryo-test) in gamma-irradiated cherry seeds

    International Nuclear Information System (INIS)

    Todoroki, Setsuko; Hayashi, Toru

    2002-01-01

    Cherry fruits were irradiated with gamma-rays at doses up to 200Gy (effective dose for disinfestation of codling moth), and DNA strand break in seed embryos was investigated by using alkaline comet assay. Immediately after irradiation (≥100Gy), DNA from embryos produced comets with a long and wide tail due to fragmentation. In control cells, DNA relaxed and produced comet with very short tail (with few strand break). After 72h storage, DNA from fruits irradiated at 200 Gy showed comets with little tail and tail moment of comets was same as un-irradiated control. These results indicate that the strand breaks of DNA caused by irradiation in fresh seed embryo are repaired during storage. On the contrary, the ability of germination lost by irradiation did not restored, a dose of 100Gy and more retarded shoot elongation. In cherries irradiated at 100Gy, the shooting percentage was less than 50% at 4th day after incubation. Germination test (Half embryo test) can be discriminate between irradiated and un-irradiated cherries. (author)

  4. Comparison of DNA comet assay and germination test (half-embryo-test) in gamma-irradiated cherry seeds

    International Nuclear Information System (INIS)

    Todoroki, S.; Hayashi, T.

    2002-01-01

    Cherry fruits were irradiated with gamma-rays at doses up to 200Gy (effective dose for disinfestation of codling moth), and DNA strand break in seed embryos was investigated by using alkaline comet assay. Immediately after irradiation (>-100Gy), DNA from embryos produced comets with a long and wide tail due to fragmentation. In control cells, DNA relaxed and produced comet with very short tail (with few strand break). After 72h storage, DNA from fruits irradiated at 200 Gy showed comets with little tail and tail moment of comets was same as un-irradiated control. These results indicate that the strand breaks of DNA caused by irradiation in fresh seed embryo are repaired during storage. On the contrary, the ability of germination lost by irradiation did not restored, a dose of 100Gy and more retarded shoot elongation. In cherries irradiated at 100Gy, the shooting percentage was less than 50% at 4th day after incubation. Germination test (Half embryo test) can be discriminate between irradiated and un-irradiated cherries

  5. Radiation-Induced Second Cancer Risk Estimates From Radionuclide Therapy

    Science.gov (United States)

    Bednarz, Bryan; Besemer, Abigail

    2017-09-01

    The use of radionuclide therapy in the clinical setting is expected to increase significantly over the next decade. There is an important need to understand the radiation-induced second cancer risk associated with these procedures. In this study the radiation-induced cancer risk in five radionuclide therapy patients was investigated. These patients underwent serial SPECT imaging scans following injection as part of a clinical trial testing the efficacy of a 131Iodine-labeled radiopharmaceutical. Using these datasets the committed absorbed doses to multiple sensitive structures were calculated using RAPID, which is a novel Monte Carlo-based 3D dosimetry platform developed for personalized dosimetry. The excess relative risk (ERR) for radiation-induced cancer in these structures was then derived from these dose estimates following the recommendations set forth in the BEIR VII report. The radiation-induced leukemia ERR was highest among all sites considered reaching a maximum value of approximately 4.5. The radiation-induced cancer risk in the kidneys, liver and spleen ranged between 0.3 and 1.3. The lifetime attributable risks (LARs) were also calculated, which ranged from 30 to 1700 cancers per 100,000 persons and were highest for leukemia and the liver for both males and females followed by radiation-induced spleen and kidney cancer. The risks associated with radionuclide therapy are similar to the risk associated with external beam radiation therapy.

  6. Study of DNA damage induction and repair capacity of fresh and cryopreserved lymphocytes exposed to H2O2 and gamma-irradiation with the alkaline comet assay.

    Science.gov (United States)

    Visvardis, E E; Tassiou, A M; Piperakis, S M

    1997-01-31

    The alkaline SCGE assay was evaluated for use with cryopreserved lymphocytes in order to obtain results similar to the freshly isolated ones. The induction of DNA damage as well as the repair capacity of gamma-rays and H2O2 exposed cryopreserved human lymphocytes was found to be the same to that of the freshly isolated. Human lymphocytes (fresh or cryopreserved) responded differently to the effects of gamma-irradiation if compared to the H2O2 treatment. The distribution of DNA damage among gamma-irradiated lymphocytes was more homogeneous compared to H2O2, both in freshly isolated and in cryopreserved cells. 2.4 micrograms/ml phytohemagglutinin at the start of a 2-h incubation in RPMI of cryopreserved samples gave similar DNA repair and distribution patterns to the 2-h post-exposure incubation of freshly isolated lymphocytes. H2O2-induced DNA damage was not repaired completely. However, the repair of gamma-rays-induced DNA damage was more efficient. These findings confirm the different mode of action of the two agents on the induction of DNA damage, as well as, the different response of the lymphocytes' DNA repair system.

  7. Radiation-induced reactions in polymer films

    Science.gov (United States)

    Biscoglio, Michael Benedict

    Since the 1950's, there has been a considerable interest in the effects of ionizing radiation on the physical properties of polymer systems. Radiation induced chemical changes that were found to be helpful in producing specialty polymers, but also potentially harmful by degrading the physical performance of the material. Therefore, solute molecules, which act as excited state quenchers, and free radical scavengers, have been incorporated into the polymers in order to regulate the crosslinking, scission and desaturation reactions. This work is focused on using spectroscopic techniques to characterize the physical properties of polymeric media and the reactions occurring within them following pulsed radiolysis. This is done primarily by using arene doped polymer films which have highly absorbing excited states and radical ions that are easily monitored by transient studies. The probes are used to characterize the polymeric microenvironment, to monitor reaction rates, and to interfere in the radical reactions. Photophysical and photochemical characterization of partially crystalline polyethylene complements data previously obtained by conventional physical techniques for polymer characterization. Probe molecules are excluded from crystalline zones and distributed in a networked structure of amorphous zones. Upon high energy radiolysis, it is found that polyolefin systems efficiently donate all radical ions and excited states to the solute molecules, even when the energy is absorbed within the polymer crystalline zones. Studies of the subsequent reactions of the solute excited states and radical ions reveal information about their long term effectiveness as protectants. It is found that highly excited states formed by the recombination of solute radical ions are energetic enough to cause dissociation of halo-arenes. Also, arenes are found to become attached to the polymer chain through a polymer-aryl radical intermediate. These intermediates have been isolated and

  8. Boosting of DNA Vaccine-Elicited Gamma Interferon Responses in Humans by Exposure to Malaria Parasites

    National Research Council Canada - National Science Library

    Wang, Ruobing; Richie, Thomas L; Baraceros, Maria F; Rahardjo, Nancy; Gay, Tanya; Banania, Jo-Glenna; Charoenvit, Yupin; Epstein, Judith E; Luke, Thomas; Freilich, Daniel A; Norman, Jon; Hoffman, Stephen L

    2004-01-01

    A mixture of DNA plasmids expressing five Plasmodium falciparum pre-erythrocyte-stage antigens was administered with or without a DNA plasmid encoding human granulocyte-macrophage colony-stimulating factor (hGM-CSF...

  9. Nigella sativa oil Ameliorates ionizing Radiation induced cellular injury in Male Albino Rats

    International Nuclear Information System (INIS)

    Mohamed, E.T.; El-Kady, A.A.

    2013-01-01

    Nigella sativa (NS), commonly known as black seed, is a plant spices in which thymoquinone is the main active ingredient isolated from the black seeds. The seeds of Nigella sativa are used in herbal medicine all over the world for the treatment and prevention of a number of diseases. The aim of this study was focused on investigating the possible protective effect of NS against gamma radiation induced nephrotoxicity and inflammatory changes in male albino rats. Twenty four albino rats were divided into four equal groups as follows: control group, irradiated group (animals subjected to whole body gamma irradiation at a dose of 6 Gy), treated group (rats treated with 0.2 ml/kg, i.p., NS oil for 4 weeks), and treated irradiated group (animals treated with 0.2 mL/kg, i.p., NS oil for 4 weeks then exposed to whole body gamma irradiation at a dose of 6 Gy). The obtained results revealed that the administration of Nigella sativa oil to irradiated rats significantly ameliorated the changes induced in kidney antioxidant system; catalase and glutathione peroxidase activities as well as reduced glutathione concentration. Also, NS oil restored the kidney function indices (urea and creatinine) near normal level when compared with their equivalent values in irradiated rats. In addition, the changes in serum tumor necrosis factor alpha (TNF-α), Interleukin-1β (IL-1β) and Interleukin-6 (IL-6) activities were markedly improved compared to the corresponding values of irradiated group. The histopathological results showed distinctive pattern of ischemic renal injury in irradiated group, while in treated- irradiated group the renal tissues showed relatively well-preserved architecture with or without focal degeneration. In conclusion, NS acts in the kidney as a potent scavenger of free radicals to prevent or ameliorates the toxic effects of gamma irradiation as shown in the biochemical and histopathological study and also NS oil might provide substantial protection against

  10. Prophylactic role of melatonin against radiation induced damage in mouse cerebellum with special reference to Purkinje cells

    Energy Technology Data Exchange (ETDEWEB)

    Sisodia, Rashmi; Kumari, Seema; Verma, Rajesh Kumar; Bhatia, A L [Neurobiology Laboratory, Department of Zoology, University of Rajasthan, Jaipur 302004 (India)

    2006-06-15

    Melatonin, a hormone with a proven antioxidative efficacy, crosses all morphophysiological barriers, including the blood-brain barrier, and distributes throughout the cell. The present study is an attempt to investigate the prophylactic influence of a chronic low level of melatonin against an acute radiation induced oxidative stress in the cerebellum of Swiss albino mice, with special reference to Purkinje cells. After 15 days of treatment the mice were sacrificed at various intervals from 1 to 30 days. Biochemical parameters included lipid peroxidation (LPO) and glutathione (GSH) levels as the endpoints. The quantitative study included alterations in number and volume of Purkinje cells. Swiss albino mice were orally administered a very low dose of melatonin (0.25 mg/mouse/day) for 15 consecutive days before single exposure to 4 Gy gamma radiation. Melatonin checked the augmented levels of LPO, by approximately 55%, by day 30 day post-exposure. Radiation induced depleted levels of GSH could be raised by 68.9% by day 30 post-exposure. Radiation exposure resulted in a reduction of the volume of Purkinje cells and their total number. The administration of melatonin significantly protected against the radiation induced decreases in Purkinje cell volume and number. Results indicate the antioxidative properties of melatonin resulting in its prophylactic property against radiation induced biochemical and cellular alterations in the cerebellum. The findings support the idea that melatonin may be used as an anti-irradiation drug due to its potent free radical scavenging and antioxidative efficacy.

  11. The effect of mitotic inhibitors on DNA strand size and radiation-associated break repair in Down syndrome fibroblasts

    International Nuclear Information System (INIS)

    Woods, W.G.; Steiner, M.E.; Kalvonjian, S.L.

    1985-01-01

    The effect of mitotic inhibitors on formation and repair of DNA breaks was studied in cultured fibroblasts from patients with Down syndrome in order to investigate the hypothesis that the karyotyping procedure itself may play a role in the increased chromosome breakage seen in these cells after gamma radiation exposure. Using the nondenaturing elution and alkaline elution techniques to examine fibroblasts from Down syndrome patients and from controls, no specific abnormalities in Down syndrome cells could be detected after exposure to mitotic inhibitors, including rate and extent of elution of DNA from filters as well as repair of radiation-induced DNA breaks. In both normal and Down syndrome cell strains, however, exposure to mitotic inhibitors was associated with a decrease in cellular DNA strand size, suggesting the presence of drug-induced DNA strand breaks. The mechanism of increased chromosome sensitivity of Down syndrome cells to gamma radiation remains unknown. (orig.)

  12. Radiation induced emulsion polymerization of vinylidene chloride

    International Nuclear Information System (INIS)

    Panajkar, M.S.; Rao, K.N.

    1979-01-01

    Gamma ray induced emulsion polymerization of vinylidene chloride has been carried out and the percent conversion of monomer to polymer and molecular weights of emulsion polymer were measured as a function of time and emulsifier concentration. Rp was found to be dependent on 0.3 power of emulsifier concentration whereas molecular weights increased with conversion and emulsifier concentration. The number of particles N also increased with conversion contrary to Smith Ewart's theory of emulsion polymerization. The results are discussed in the light of existing theories of emulsion polymerization. (author)

  13. DNA repair and mutagenesis of singlestranded bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Doubleday, O.P.; Brandenburger, A.; Wagner, R. Jr.; Radman, M. (Brussels Univ. (Belgium)); Godson, G.N.

    1981-01-01

    Virtually all radiation-induced mutagenesis is believed to result from an error-prone repair activity (SOS repair) and to involve mutations occurring both at the site of radiation-induced lesions (targeted mutations) and in undamaged DNA (untargeted mutations). To examine the relative contributions of targeted and untargeted mutations to ..gamma.. and ultraviolet (UV) radiation mutagenesis we have determined the DNA sequences of 174 M13 revertant phages isolated from stocks of irradiated or unirradiated amber mutants grown in irradiated or unirradiated host bacteria. We have detected no obvious specificity of mutagenesis and find no evidence of a predominance of targeted mutations associated with either UV- or ..gamma..-irradiation of the phages or with the induction of the host SOS repair system. In particular, pyrimidine dimers do not appear to be the principal sites of UV-induced bare substitution mutagenesis, suggesting that such UV-induced mutagenesis may be untargeted or occur at sites of lesions other than pyrimidine dimers.

  14. Radiation induced hepatic lesions and their amelioration by Rosemarinus oficinalis

    International Nuclear Information System (INIS)

    SoyaI, Dhanraj; Goyal, P.K.

    2013-01-01

    autopsy interval (i.e. 30 days), only in experimental group. On contrary, abnormal hepatocytes increased up to day 5 after irradiation. Binucleated hepatocytes showed a biphasic mode of elevation after irradiation, first on day 2 then on day 10 post-treatment in both the groups, but the same was comparatively less marked in experimental group. Several radiation induced hepatic lesions were also visualized in both the groups, but in ROE + radiation treated group, the degree of damage was found to be considerably lesser and the recovery from such lesions was much faster to regain the normal architecture of liver. Hence, the results from the present study suggest that Rosemarinus officinalis leaves extract pretreatment provides protection against radiation-induced histopathological alterations in liver of mammals. (author)

  15. Mechanisms of radiation-induced gene responses

    International Nuclear Information System (INIS)

    Woloschak, G.E.; Paunesku, T.

    1996-01-01

    In the process of identifying genes differentially expressed in cells exposed ultraviolet radiation, we have identified a transcript having a 26-bp region that is highly conserved in a variety of species including Bacillus circulans, yeast, pumpkin, Drosophila, mouse, and man. When the 5' region (flanking region or UTR) of a gene, the sequence is predominantly in +/+ orientation with respect to the coding DNA strand; while in the coding region and the 3' region (UTR), the sequence is most frequently in the +/-orientation with respect to the coding DNA strand. In two genes, the element is split into two parts; however, in most cases, it is found only once but with a minimum of 11 consecutive nucleotides precisely depicting the original sequence. The element is found in a large number of different genes with diverse functions (from human ras p21 to B. circulans chitonase). Gel shift assays demonstrated the presence of a protein in HeLa cell extracts that binds to the sense and antisense single-stranded consensus oligomers, as well as to the double- stranded oligonucleotide. When double-stranded oligomer was used, the size shift demonstrated as additional protein-oligomer complex larger than the one bound to either sense or antisense single-stranded consensus oligomers alone. It is speculated either that this element binds to protein(s) important in maintaining DNA is a single-stranded orientation for transcription or, alternatively that this element is important in the transcription-coupled DNA repair process

  16. Molecular characterization of induced mutagenesis through gamma ...

    African Journals Online (AJOL)

    Genetic variability in Jatropha curcas was induced by different doses (5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 kR) of gamma-rays. Gamma radiation induced earliness in flowering and the plants set flowers earlier than that of control, which took longer duration of 327 days for flowering. The improved reproductive and yield ...

  17. Radiation-induced adaptive response in human lymphoblast

    International Nuclear Information System (INIS)

    Yatagai, Fumio; Sugasawa, Kaoru

    2009-01-01

    Described are the genetic analysis of variant strains obtained by the optimal condition for radiation-induced adaptive response (AR), and molecular elucidation of the suppression of concomitant mutation. The TK6 cells (heterozygous thymidine kinase, +/-) were used for detection of mutation by loss of heterozygosity (LOH). The optimal conditions for reducing the mutation by subsequent irradiation (SI) to its rate of about 60% (vs control 100%, no PI) were found to be 5 cGy of pre-irradiation (PI) of X-ray and 2 Gy of SI with the interval of 6 hr, where mutated cells were of non-LOH type in around 25% and homo-LOH type by homologous recombination (HR) in 60%. By cDNA sequencing, the former cells having changed bases were found to be in variant strain ratio of 1/8 vs control 7/18, suggesting that the mutation was decreased mainly by suppression of base change. Expression of XPC protein, an important component for recognition of the base damage in global genome nucleotide excision repair, was studied by Western blotting as the possible mechanism of suppressing the mutation, which revealed different time dynamics of the protein in cells with PI+SI and SI alone (control). To see the effect of PI on the double strand break (DSB) repair, cells with PI were infected with restriction enzyme I-SceI vector to yield DSB instead of SI, which revealed more efficient repair (70% increase) by HR than control, without significant difference in non-homologous end-joining repair. Micro-array analysis to study the gene expression in the present experimental conditions for AR is in progress. The TK6 cells used here were thought useful for additional studies of the mechanism of AR as mutation by direct or indirect irradiation can be tested. (K.T.)

  18. Protective effect of zingerone, a dietary compound against radiation induced damage

    International Nuclear Information System (INIS)

    Satish Rao, B.S.; Rao, Nageshwar

    2012-01-01

    The radioprotective potential of phenolic alkanone, Zingerone (ZO) was investigated using human peripheral blood lymphocytes as well as Chinese hamster fibroblast (V79) cells growing in vitro and in vivo by using Swiss albino mice exposed to gamma radiation. In the in vivo studies, mice were administered with ZO (10-100 mg/kg b.wt), once daily for five consecutive days. One hour after the last administration of ZO on the fifth day, animals were whole body exposed to 10 Gy gamma radiations. The radioprotective potential was assessed using animal survival, haemopoietic stem cell survival (CFU) assay, mouse bone marrow micronucleus test, histological observations of intestinal and bone marrow damage. Effect of ZO pretreatment on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPx) levels was also analyzed. ZO treatment resulted increase in the LD50/30 by 1.8 Gy (dose reduction factor = 1.2). The number of spleen colonies after whole body irradiation of mice (4.5 or 7.5 Gy) was increased when ZO was administered 1 h prior to irradiation. The histological observations indicated a decline in the villus height and crypt number with an increase in goblet and dead cell population in the irradiated group, which was normalized by pretreatment with ZO. A significant (p < 0.001) reduction in micronucleated polychromatic, normochromatic erythrocytes, increased PCE/NCE ratio, increase in the GSH, GST, SOD, CAT and decreased LPx levels were observed in ZO by pretreated group when compared to the irradiated animals. Our in vitro and in vivo studies demonstrate the potential of ZO in mitigating radiation-induced cytotoxic, genotoxicity, apoptosis in cell culture and animal mortality, cytogenetic damage, intestinal and bone marrow protection in vivo. Radioprotective potential of ZO may be attributed to the inhibition radiation-induced decline in the endogenous antioxidant levels

  19. DNA damage induced by radiation plasmodial mixed + gamma thermal neutrons in the presence and absence of free radical scavenger

    International Nuclear Information System (INIS)

    Rodriguez Gual, Maritza; Mas Milian, Felix; Gouveia, Andreia; Deppman, Airton

    2010-01-01

    In this work is quantified the damage in DNA plasmid induced by mixed radiation (thermal neutron and gamma rays) for first time. For the study was used the pBs KS+ plasmid of 2961 bp in aqueous solution of the 88 ng/μL with 0, 2 and 20 mmol/L of glycerol which acts as a free radicals scavenger. This plasmid changes its form of supercoiled to circular when a simple strand break is produced, and passes to a linear form when a double strand break is produced in the chain. Quantifying the fractions that exist in each of these forms is possible to estimate the effect of radiation on DNA. The irradiations were carried out in the radial channel 3 at IEA-R1 research reactor of the Instituto de Pesquisas Energeticas y Nucleares in Sao Paulo, Brazil. DNA forms were separated by agarose gel electrophoresis. For quantification the program GelAnalis was used. The values of the fractions of DNA in various forms were plotted as a function of dose and fitted to exponential and linear functions to obtaining the probabilities of simple and double strand breaks normalized by dose and molecular mass. The results showed the protective action of free radical scavenger against damage induced for radiation which corroborates the previous results found with other ionizing radiations. Yields of SSB and DSB will be of interest for the validation of the different models that attempt to reproduce the experimental results

  20. Ferulic acid ameliorates radiation induced duodenal inflammation

    International Nuclear Information System (INIS)

    Das, Ujjal; Manna, Krishnendu; Sengupta, Aaveri; Biswas, Sushobhan; Chakrabarty, Arpita; Dey, Sanjit

    2016-01-01

    Ionizing radiation creates oxidative stress followed by inflammation through reactive oxygen species (ROS) and altering the status of redox sensitive enzymes. In the current study we aimed to evaluate the effect of ferulic acid (FA) on increasing doses of ionizing radiation mediated oxidative stress and inflammation using in vivo murine duodenum. To delineate the hypothesis we exposed mice with 2.5, 5 and 10 Gy gamma radiation doses in presence and absence of the (FA). FA was administered orally at a fixed dose of 50mg/ kg bw for 5 days before radiation exposure. Different techniques such as biochemical assays, immune blot, and microscopic analysis for histopathology, flow cytometry and scanning electron microscopy were employed to achieve the goal

  1. Radiation-induced degradation of galactomannan polysaccharides

    International Nuclear Information System (INIS)

    Sen, Murat; Yolacan, Burcu; Gueven, Olgun

    2007-01-01

    In this study, guar gum, tara gum and locust bean gum were irradiated in a gamma cell in the solid state. The change in their molecular weights were determined by size exclusion chromatography analysis and the change in their viscosity values with change of temperature and irradiation dose were determined. Chain scission yield, G(s), and degradation rate values were calculated. The calculated G(s) values is 1.09 ± 0.16, 1.07 ± 0.06, 0.85 ± 0.10 for GG, TG and LBG, respectively. The effect of mannose-galactose ratio and initial molecular weight of these gums on the degradation behavior were discussed

  2. Aging and radiation induced alternations in liver histones

    International Nuclear Information System (INIS)

    Kozurkova, M.; Misurova, E.; Kropacova, K.

    1994-01-01

    Age-related changes in histones in the liver of normal rats and in rats irradiated with 5.7 Gy gamma rays were examined. Quantitative histone changes in growing and aging rats (from 1 to 28 months of age) were found to be mild only. As they paralleled the DNA changes, the histone /DNA ratio remained stable with age. In total extracted histones there was a decrease in the H1 proportion in older groups with preceding increase in the H1 grad proportion. Thirty minutes after irradiation the amount of histones was reduced with age, probably due to an impaired extractability of histones. As the quantitative DNA changes were milder, the histone?DNA ratio decreased in aging liver after irradiation. Similar patterns of changes in proportion of the H1 fraction and H1 grad sub-fraction were observed in irradiated and nonirradiated animals in the former with an earlier onset. Irradiation, therefore, accelerated spontaneous age-related alternations. (author)

  3. Role of endothelium in radiation-induced normal tissue damages

    International Nuclear Information System (INIS)

    Milliat, F.

    2007-05-01

    More than half of cancers are treated with radiation therapy alone or in combination with surgery and/or chemotherapy. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate. Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. The knowledge of normal tissue radiobiology is needed to determine molecular mechanisms involved in normal tissue pathogenic pathways in order to identify therapeutic targets and develop strategies to prevent and /or reduce side effects of radiation therapy. The endothelium is known to play a critical role in radiation-induced injury. Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy. We describe a new role for the TGF-b/Smad pathway in the pathogenesis of radiation-induced damages. TGF-b/Smad pathway is involved in the fibro-genic phenotype of VSMC induced by irradiated EC as well as in the radiation-induced PAI-1 expression in endothelial cells. (author)

  4. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K. [Tokyo Univ., Tokyo (Japan); Mishima, K. [Kyoto Univ., Kyoto (Japan); Furuya, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2003-07-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by {gamma}-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by {gamma}-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co {gamma}-ray irradiation.

  5. Role of Cardamom (Elettaria cardamomum) in Ameliorating Radiation Induced Oxidative Stress In Rats

    International Nuclear Information System (INIS)

    Darwish, M.M.; Abd El Azime, A. Sh.

    2013-01-01

    Radiation is one of the most widespread sources of environmental stress in living environment which cause oxidative stress and metabolic changes. The present study aims to evaluate the antioxidant effect of Cardamom (Elettaria cardamomum) on gamma radiation-induced oxidative damage in liver and heart tis sues. The study was conducted on forty (40) rats which were classified into four equal groups. Group1: Control group, Group. 2: rats given cardamom in basal diet.Group3: Irradiated rats, rats were subjected to whole body gamma irradiation at 6 Gy delivere d as single exposure dose. Group 4: irradiated +cardamom: rats receiving cardamom for 4 weeks and irradiated. The animals were scarified 24h after irradiation. Irradiated animals had significant increase in oxidative stress markers in liver and heart tissues expressed by significant increase of malondialdehyde (MDA) content associated to significant depletion of superoxide dismutase (SOD) , catalase (CAT) activities, and reduced glutathione (GSH) content . Hepatic and cardiac changes included significant increases of serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) , total cholesterol(TC), triacylglycerol(TAG), low-density lipoprotein cholesterol(LDL-C), and iron concentration. While, a significant decre ase in high-density lipoprotein-cholesterol (HDL-C), manganese and copper were observed. Addition of cardamom to the basal diet prior to gamma radiation, improved the tested parameters . So it is a therapeutic alternative for oxidative stress, hyperlipidaemia and trace elements changes. . The data obtained in this study suggest that cardamom may prevent liver and heart from radiation-induced damage.

  6. Evaluation of radiation-induced genotoxicity on human melanoma cells (SK-MEL-37) by flow cytometry

    Energy Technology Data Exchange (ETDEWEB)

    Bonfim, Leticia; Carvalho, Luma Ramirez de; Vieira, Daniel Perez, E-mail: leticia.bonfim@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    Micronucleus assay is a test used to evaluate genotoxic damage in cells, which can be caused by various factors, like ionizing radiation. Interactions between radiation energies and DNA can cause breakage, leading to use chromosomal mutations or loss of genetic material, important events that could be induced in solid tumors to mitigate its expansion within human body. Melanoma has been described as a tumor with increased radio resistance. This work evaluated micronuclei percentages (%MN) in human melanoma cells (SK-MEL-37), irradiated by gamma radiation, with doses between 0 and 16Gy. Cell suspensions were irradiated in PBS by a {sup 60}Co source in doses between 0 and 16Gy, and incubated by 48h. Then cell membranes were lysed in the presence of SYTOX Green and EMA dyes, preserving nuclear membranes. Using this method, EMA-stained nuclei could be discriminated as those derived from dead cells, and SYTOX nuclei and micronuclei could be quantified. Micronuclei percentages were found to be proportional to dose, (R2 = 0.997). Only the highest dose (16Gy) could induce statistically significant increase of MN (p<0.0001), although cultures irradiated by 4, 8 and 16Gy showed significant increase of dead cell fractions. Calculation of the nuclei-to-beads ratio showed that 8 and 16Gy could reduce melanoma cell proliferation. Results showed that although cell death and loss of proliferative capacity could be observed on cultures irradiated at lower doses, genotoxic damage could be induced only on a higher dose. Resistance to radiation-induced genotoxicity could explain a relatively high radio resistance of melanoma tumors. (author)

  7. A novel preparation of surface-modified paramagnetic magnetite/polystyrene nanocomposite microspheres by radiation-induced miniemulsion polymerization.

    Science.gov (United States)

    Qian, Zhen; Zhang, Zhicheng; Chen, Yun

    2008-11-15

    A novel and facile approach to the preparation of paramagnetic magnetite/polystyrene nanocomposite microspheres by 60Co gamma-ray radiation-induced miniemulsion polymerization is reported. First, we modified the magnetite nanoparticles (MPs) with a Y-shaped surfactant: 12-hexanoyloxy-9-octadecenoic acid (HOA). Nanocomposite microspheres consisting of polystyrene-iron oxide nanoparticles then were prepared by the radiation-induced miniemulsion polymerization of styrene in the presence of HOA-modified MPs using HOA as stabilizer. The final products were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The effects of the dose rate, the amounts of added hexadecane (HD) and MPs, and the morphology of the final products were studied. We have also studied the polymerization kinetics to prove the miniemulsion polymerization mechanism of the nanocomposite microspheres.

  8. Methylglyoxal-bis(guanylhydrazone), a polyamine analogue, sensitized γ-radiation-induced cell death in HL-60 leukemia cells Sensitizing effect of MGBG on γ-radiation-induced cell death.

    Science.gov (United States)

    Kim, Jin Sik; Lee, Jin; Chung, Hai Won; Choi, Han; Paik, Sang Gi; Kim, In Gyu

    2006-09-01

    Methylglyoxal-bis(guanylhydrazone) (MGBG), a polyamine analogue, has been known to inhibit the biosynthesis of polyamines, which are important in cell proliferation. We showed that MGBG treatment significantly affected γ-radiation-induced cell cycle transition (G(1)/G(0)→S→G(2)/M) and thus γ-radiation-induced cell death. As determined by micronuclei and comet assay, we showed that it sensitized the cytotoxic effect induced by γ-radiation. One of the reasons is that polyamine depletion by MGBG treatment did not effectively protect against the chemical (OH) or physical damage to DNA caused by γ-radiation. Through in vitro experiment, we confirmed that DNA strand breaks induced by γ-radiation was prevented more effectively in the presence of polyamines (spermine and spermidine) than in the absence of polyamines. MGBG also blocks the cell cycle transition caused by γ-radiation (G(2) arrest), which helps protect cells by allowing time for DNA repair before entry into mitosis or apoptosis, via the down regulation of cyclin D1, which mediates the transition from G(1) to S phase of cell cycle, and ataxia telangiectasia mutated, which is involved in the DNA sensing, repair and cell cycle check point. Therefore, the abrogation of G(2) arrest sensitizes cells to the effect of γ-radiation. As a result, γ-radiation-induced cell death increased by about 2.5-3.0-fold in cells treated with MGBG. However, exogenous spermidine supplement partially relieved this γ-radiation-induced cytotoxicity and cell death. These findings suggest a potentially therapeutic strategy for increasing the cytotoxic efficacy of γ-radiation.

  9. Protective effect of flax seed oil against radiation induced hematological alterations in mammals

    International Nuclear Information System (INIS)

    Sharma, Jyoti; Singh, Ritu; Goyal, P.K.; Singh, Seema

    2014-01-01

    Human beings are exposed to ionizing and non ionizing radiation from natural as well as manmade sources. Ionizing radiations are one of the predominant exogenous factors that have deleterious consequences to human life. Exposure to ionizing radiations damages the hematopoietic, gastrointestinal or central nervous systems, depending on radiation dose. Hence, there is an urgent need to prevent such deleterious effects caused due to ionizing radiations. Chemical protection involves the use of synthetic and natural products against planned radiation exposure. Medicinal plants are rich in antioxidants and their chemical constituents may be the potential source for radioprotective agents. Linum usitatissimum plant (family: Linaceae), source of flaxseed oil (FSO), is well known for its anticarcinogenic, antidiabetic, cardioprotector, antiulcer properties owing to the presence of various phytochemicals. The present study has been focused to find out the preventive action of flaxseed oil against radiation induced hematological and biochemical lesions in mammals. For this purpose, FSO (50μL/animal/day) was orally administered to Swiss albino mice for five days, prior to 6 Gy gamma radiation exposure. The animals were sacrificed on 1 st , 3 rd , 7 th , 15 th and 30 th day after irradiation. Radiation treated control group exhibited significant reduction in erythrocytes count, hemoglobin content, hematocrit value and total WBC count in peripheral blood. In contrast, pretreatment with FSO significantly increased all these blood constituents. Further, the antioxidant parameters such as reduced glutathione, catalase, and superoxide dismutase showed a significant elevation in FSO pretreated group which were reduced in irradiated control group. Similarly, radiation induced increase lipid peroxidation in blood was significantly inhibited after FSO treatment. The present results indicate that the flaxseed oil has the ability to debilitate the radiation induced adverse alterations in

  10. Control of radiation-induced diarrhea with cholestyramine

    International Nuclear Information System (INIS)

    Heusinkveld, R.S.; Manning, M.R.; Aristizabal, S.A.

    1978-01-01

    Cholestyramine is a non-absorbable ion-exchange resin which specifically binds bile salts. We have treated seven patients with acute or chronic radiation-induced diarrhea that was refractory to the usual methods of control with cholestyramine. In each case, the diarrhea was controlled with cholestyramine. This observation supports previous experimental work with animals which indicated that bile salts contribute to the genesis of radiation-induced diarrhea. Cholestyramine is well-tolerated, but should not be administered with certain oral medications. The results of this small series are preliminary, but point the way toward a more extensive clinical trial to define the usefulness of cholestyramine in the treatment of refractory acute or chronic radiation-induced diarrhea

  11. Thioredoxin mitigates radiation-induced hematopoietic stem cell injury in mice

    Directory of Open Access Journals (Sweden)

    Pasupathi Sundaramoorthy

    2017-11-01

    Full Text Available Abstract Background Radiation exposure poses a significant threat to public health. Hematopoietic injury is one of the major manifestations of acute radiation sickness. Protection and/or mitigation of hematopoietic stem cells (HSCs from radiation injury is an important goal in the development of medical countermeasure agents (MCM. We recently identified thioredoxin (TXN as a novel molecule that has marked protective and proliferative effects on HSCs. In the current study, we investigated the effectiveness of TXN in rescuing mice from a lethal dose of total body radiation (TBI and in enhancing hematopoietic reconstitution following a lethal dose of irradiation. Methods We used in-vivo and in-vitro methods to understand the biological and molecular mechanisms of TXN on radiation mitigation. BABL/c mice were used for the survival study and a flow cytometer was used to quantify the HSC population and cell senescence. A hematology analyzer was used for the peripheral blood cell count, including white blood cells (WBCs, red blood cells (RBCs, hemoglobin, and platelets. Colony forming unit (CFU assay was used to study the colongenic function of HSCs. Hematoxylin and eosin staining was used to determine the bone marrow cellularity. Senescence-associated β-galactosidase assay was used for cell senescence. Western blot analysis was used to evaluate the DNA damage and senescence protein expression. Immunofluorescence staining was used to measure the expression of γ-H2AX foci for DNA damage. Results We found that administration of TXN 24 h following irradiation significantly mitigates BALB/c mice from TBI-induced death: 70% of TXN-treated mice survived, whereas only 25% of saline-treated mice survived. TXN administration led to enhanced recovery of peripheral blood cell counts, bone marrow cellularity, and HSC population as measured by c-Kit+Sca-1+Lin– (KSL cells, SLAM + KSL cells and CFUs. TXN treatment reduced cell senescence and radiation-induced

  12. DNA damage and biological expression of adenovirus: A comparison of liquid versus frozen conditions of exposure to gamma rays

    International Nuclear Information System (INIS)

    Bennett, C.B.; Rainbow, A.J.

    1989-01-01

    Human adenovirus type 2 (Ad 2) was irradiated with 137Cs gamma rays in the liquid state at 0 degree C. DNA breaks were correlated with the inactivation of several viral functions and compared to results obtained previously for irradiation of Ad 2 under frozen conditions at -75 degrees C. Irradiation at 0 degree C induced 170 +/- 20 single-strand breaks and 2.6 +/- 0.4 double-strand breaks/Gy/10(12) Da in the viral DNA. Viral adsorption to human KB cells was inactivated with a D0 of 9.72 +/- 1.18 kGy, whereas the inactivation of Ad 2 plaque formation had a D0 of 0.99 +/- 0.14 or 1.1 +/- 0.29 kGy when corrected for the effect of radiation on virus adsorption. For the adsorbed virus, an average of 4.3 +/- 1.7 single-strand and 0.065 +/- 0.02 double-strand breaks were induced in the viral DNA per lethal hit. In contrast, irradiation of Ad 2 at -75 degrees C results in 2.6- to 3.4-fold less DNA breakage per Gy and a 5.6-fold increase in D0 for plaque formation of the adsorbed virus. Furthermore, although host cell reactivation (HCR) of Ad 2 viral structural antigen production for irradiated virus was substantially reduced in the xeroderma pigmentosum fibroblast strain (XP25RO) compared to normal strains for irradiation at -75 degrees C (57% HCR), it was only slightly reduced compared to normal for irradiation at 0 degree C (88% HCR). These results indicate that the spectrum of DNA damage is both quantitatively and qualitatively different for the two conditions of irradiation

  13. Radiation-induced apoptosis of chicken lymphocyte B-cell line DT40

    International Nuclear Information System (INIS)

    Furusawa, Y.; Aoki, M.; Takakura, K.

    2003-01-01

    Full text: Ionizing radiation causes lesions of DNA, cell cycle arrest, induced cell death, and apoptosis in the irradiated cells. Then it is easy to expect that those events would be increased in a cell line which is defective in DNA repair system. However, induction of apoptosis by irradiation takes so complicated process when the cells are defective of DNA repair system. Indeed by many recent studies it has been clarified that DNA repair gene is also concerned with apoptotic event and some study shows the contrary data. Thus, the relationship between the genetics of apoptosis and that of DNA repair is still unclear. In this study two kinds of DNA repair proteins, Rad54 and Ku70, were focused. Proteins of Rad54 and Ku70 have important role at two type of DNA repair systems called homologous recombination repair and non-homologous end joining repair, respectively. 4 phenotypes of DT40, parent type, ku70-/-, rad54-/- and ku70-/-/rad54-/- were used to study the radiation-induced apoptosis (Previous study shows that survival fraction of 4 phenotypes of DT40 is decreased in the cell line, in which DNA repair gene is defective). From the results in this study, two things are clarifies. One is that the dependence of apoptotic index on phenotypes is so different between at low dose and at high dose irradiation. The other is that Ku70 has effective role to induce apoptosis in DT40 irradiated with high dose X-rays

  14. Acemannan (a polysaccharides of Aloe vera gel) protects against radiation induced mortality by modulation of immunosuppression

    International Nuclear Information System (INIS)

    Kumar, Sumit; Tiku, Ashu Bhan

    2014-01-01

    Acemannan (poly-acetylated mannose) is an active component of Aloe vera gel and has been reported to have anticancerous, antimicrobial and shown to stimulate the development and proliferation of the hematopoietic cells. The anticancerous properties of acemannan have been attributed to the modulation of immune system rather then cytotoxicity. Therefore objective of the present study was to evaluate radioprotective efficacy of acemannan against radiation induced immune suppression using Swiss albino mice as a model system. For In-vivo studies mice were treated for 7 days orally prior to irradiation (5 Gy). Animals were sacrificed at different time point to study the effect on cellular proliferation, DNA damage, apoptosis and ROS level, cytokines level, antioxidant enzymes, nitric oxide and protein expression. For survival studies mice were treated with acemannan for 7 days pre or post irradiation and survival was monitored for 30 days. Acemannan showed a significant induction of proliferation of splenocytes in radiation treated groups. Beside a decrease in radiation induced ROS and DNA damage resulted in the reduction of apoptosis in murine splenocytes. Acemannan restored the antioxidant enzyme level (catalase, SOD, DTD and GST) and maintained the proper redox status via GSH, in irradiated mice. Further acemannan was shown to induce the hematopoiesis (peripheral lymphocytes cells, spleen colony cells, spleen index) by increasing the level of the pro-hematopoiesis cytokines (IL-1, TNF-α). Being an immunomodulator, acemannan reduced the level of the inflammation (IL-6, nitric oxide). Also the multiple mechanisms operational at cellular and molecule levelled to the reduction of radiation induced mortality of mice in both pre and post-irradiation studies. On the basis of the above results it can be concluded that radioprotective effects of the acemannan was due to its immunomodulatory activity and could have application for radio-therapeutic purposes. (author)

  15. Protective effects of acemannan against radiation induced damage in Swiss albino mice

    International Nuclear Information System (INIS)

    Kumar, Sumit; Tiku, Ashu Bhan

    2013-01-01

    Aloe vera is one of the well known medicinal plant and posses a large no. of beneficial bioactive components like Anthraquinone, C-glycosides, anthrones, emodin, acemannan etc. Acemannan (poly-acetylated mannose) is one of the active component present in aloe vera gel and has anticancerous and antimicrobial properties. It has also been reported to have wound healing properties and has role as immunomodulator. The objective of the present study was to evaluate protective efficacy of acemannan against radiation induced damage in in-vitro and in in-vivo using murine splenocytes and Swiss albino mice as a model system. In vitro studies were done using primary mouse splenocytes cultures and effect of radiation on cell proliferation, viability, ROS, DNA damage and apoptosis were studies using MTT, trypan blue, DCFDA, single cell gel electrophoresis and ladder assay respectively. For in-vivo studies mice were pretreated with different doses of drug for 7 days followed by irradiation (5 Gy). Twenty four hours post-irradiation mice was sacrificed to observe the activity of antioxidant enzymes and level of protein expression. Acemannan showed a significant induction of proliferation of splenocytes in radiation treated groups both in in-vitro and in in-vivo. Beside a decrease in radiation induced ROS and DNA damage was observed in in-vitro system. Acemannan treatment was able to reduce the radiation induced apoptosis by about 50% both in in-vitro and in in-vivo. In in-vivo acemannan helps in the restoration of the antioxidant enzyme level (catalase, SOD, DTD and GST) besides maintaining the proper redox status via GSH, in irradiated mice. In our studies a dose of 50 mg/kg body wt of acemannan showed the best protective effects. On the basis of the above results it could be concluded that acemannan may have radioprotective potential. (author)

  16. Nicaraven attenuates radiation-induced injury in hematopoietic stem/progenitor cells in mice.

    Directory of Open Access Journals (Sweden)

    Miho Kawakatsu

    Full Text Available Nicaraven, a chemically synthesized hydroxyl radical-specific scavenger, has been demonstrated to protect against ischemia-reperfusion injury in various organs. We investigated whether nicaraven can attenuate radiation-induced injury in hematopoietic stem/progenitor cells, which is the conmen complication of radiotherapy and one of the major causes of death in sub-acute phase after accidental exposure to high dose radiation. C57BL/6 mice were exposed to 1 Gy γ-ray radiation daily for 5 days in succession (a total of 5 Gy, and given nicaraven or a placebo after each exposure. The mice were sacrificed 2 days after the last radiation treatment, and the protective effects and relevant mechanisms of nicaraven in hematopoietic stem/progenitor cells with radiation-induced damage were investigated by ex vivo examination. We found that post-radiation administration of nicaraven significantly increased the number, improved the colony-forming capacity, and decreased the DNA damage of hematopoietic stem/progenitor cells. The urinary levels of 8-oxo-2'-deoxyguanosine, a marker of DNA oxidation, were significantly lower in mice that were given nicaraven compared with those that received a placebo treatment, although the levels of intracellular and mitochondrial reactive oxygen species in the bone marrow cells did not differ significantly between the two groups. Interestingly, compared with the placebo treatment, the administration of nicaraven significantly decreased the levels of the inflammatory cytokines IL-6 and TNF-α in the plasma of mice. Our data suggest that nicaraven effectively diminished the effects of radiation-induced injury in hematopoietic stem/progenitor cells, which is likely associated with the anti-oxidative and anti-inflammatory properties of this compound.

  17. Cancer predispostion, radiosensitivity and the risk of radiation-induced cancers. I. Background

    International Nuclear Information System (INIS)

    Sankaranarayanan, K.; Chakraborty, R.

    1995-01-01

    This paper presents an overview of current knowledge on genetic predisposition to cancer and on enhanced sensitivity of cancer-predisposed genotypes to cancers induced by ionizing radiation. It is intended to provide a background and set the stage for the next papers in this series in which we will assess how such heterogeneity in a population may affect estimates of the risk of radiation-induced cancers. The main findings of the present paper are the following: (1) open-quotes Cancer-predisposing genesclose quotes (i.e. those at which germinal mutations predispose to cancer) are present in the human genome; these genes are responsible not only for the rare familial cancer syndromes but also for a proportion of the common cancers. At least 21 such genes have now been cloned (including 9 tumor suppressor genes, 11 DNA repair genes and 1 proto-oncogene); further, at least 8 putative tumor suppressor genes and a gene involved in ataxia telangiectasia have been localized to specific chromosomes. (2) These genes play crucial roles in the control of cellular proliferation, programmed cell death (apoptosis) and/or one or another DNA repair pathway. Consequently, mutations in these genes are likely to open-quotes liberateclose quotes the cells from the normal constraints imposed by them, resulting in unconstrained growth characteristic of cancer. (3) At present, the evidence for increased sensitivity of cancer-predisposed genotypes to radiation-induced cancers is limited. However, current knowledge of the known functions of the cancer-predisposing genes and of the consequences of mutations in these provide (a) sufficient grounds for assuming that the genotypes of those predisposed to cancer may be at an increased risk for radiation-induced cancers and (b) the rationale for attempts to estimate quantitatively the impact of genotype-dependent differences in cancer predisposition and radiosensitivity on cancer risks in an irradiated population. 202 refs., 4 tabs

  18. Effects of gamma irradiation on the DNA-protein complex between the estrogen response element and the estrogen receptor

    Energy Technology Data Exchange (ETDEWEB)

    Stisova, Viktorie [Department of Radiation Dosimetry, Nuclear Physics Institute AS CR, Na Truhlarce 39/64, 18086 Praha 8 (Czech Republic); Goffinont, Stephane; Spotheim-Maurizot, Melanie [Centre de Biophysique Moleculaire CNRS, rue Charles Sadron, 45071 Orleans Cedex 2 (France); Davidkova, Marie, E-mail: davidkova@ujf.cas.c [Department of Radiation Dosimetry, Nuclear Physics Institute AS CR, Na Truhlarce 39/64, 18086 Praha 8 (Czech Republic)

    2010-08-15

    Signaling by estrogens, risk factors in breast cancer, is mediated through their binding to the estrogen receptor protein (ER), followed by the formation of a complex between ER and a DNA sequence, called estrogen response element (ERE). Anti-estrogens act as competitive inhibitors by blocking the signal transduction. We have studied in vitro the radiosensitivity of the complex between ERalpha, a subtype of this receptor, and a DNA fragment bearing ERE, as well as the influence of an estrogen (estradiol) or an anti-estrogen (tamoxifen) on this radiosensitivity. We observe that the complex is destabilized upon irradiation with gamma rays in aerated aqueous solution. The analysis of the decrease of binding abilities of the two partners shows that destabilization is mainly due to the damage to the protein. The destabilization is reduced when irradiating in presence of tamoxifen and is increased in presence of estradiol. These effects are due to opposite influences of the ligands on the loss of binding ability of ER. The mechanism that can account for our results is: binding of estradiol or tamoxifen induces distinct structural changes of the ER ligand-binding domain that can trigger (by allostery) distinct structural changes of the ER DNA-binding domains and thus, can differently affect ER-ERE interaction.

  19. Characterization of radiation-induced apoptosis in developing central nervous system

    International Nuclear Information System (INIS)

    Perez, M.R.; Gisone, P.; Dubner, D.; Michelin, S.; Sanjurjo, J.

    2000-01-01

    Prenatal exposures to ionizing radiation may cause a variety of effects on Central Nervous System (CNS) including microcephaly, severe mental retardation and lower intelligence tests score. The highest risks occur between 8 and 15 week of gestational age, simultaneously with the greatest neuroblastic proliferation and migration to cerebral cortex. It has been shown that radiation induce apoptosis in CNS, primarily in neonatal or early postnatal brain. At the same time, programmed cell death plays an important role in normal development of embrionic tissues, especially in the neuronal system. The purpose of the present study was the characterization and quantification of the apoptosis, the effectivity of different neuroprotectors, and the involvement of the caspase-3 in the programmed cellular death in our model. Evidence for apoptotic like features included: apoptotic nuclei observed by conventional and fluorescent staining, analysis of DNA fragmentation in agarosa gels and flow cytometric quantification. To gain an insight about the neuroprotective effect of different modulators of neuroprotection, it has been tested: Protein synthesis inhibitor, Compounds capable of reducing the effect of oxidative stress, Nitric oxide synthase (NOS) inhibitors and glutamate receptor antagonists. Cerebrocortical micromass cultures were prepared from fetuses of Wistar rats removed between 15 and 19 embronic day (ED) and 5 postnatal day (PN). Irradiation was performed two hours after seeding, with a Co60 source and a fast beam of the research reactor RA1 with a neutron-gamma field. Conventional staining was performed with May Grunwald Giemsa. Fluorescent staining consisted in a mixture of Propidium iodide (IP), fluorescein diacetate (FDA) and Hoescht 33342. Analysis of DNA fragmentation was carried out on 1,8% agarosa gel stained with ethidium bromide, visualized and photographed by UV illumination. Caspase-3 activation was performed using ApoAlert TM Kit. The quantification of

  20. Radiation-induced radical ions in calcium sulfite

    Science.gov (United States)

    Bogushevich, S. E.

    2006-07-01

    We have used EPR to study the effect of γ radiation on calcium sulfite. We have observed and identified the radiation-induced radical ions SO 2 - (iso) with g = 2.0055 and SO 2 - (orth-1) with g1 = 2.0093, g2 = 2.0051, g3 = 2.0020, identical to the initial and thermally induced SO 2 - respectively, SO 3 - (iso) with g = 2.0031 and SO 3 - (axial) with g⊥ = 2.0040, g∥ = 2.0023, identical to mechanically induced SO 3 - . We have established the participation of radiation-induced radical ions SO 3 - in formation of post-radiation SO 2 - .

  1. Radiation-induced fibrosarcoma following treatment for breast cancer

    International Nuclear Information System (INIS)

    Adam, Y.G.; Reif, R.

    1977-01-01

    A patient with radiation-induced fibrosarcoma following mastectomy and postoperative radiation for bilateral breast carcinoma is described. Only six such cases have been reported in the literature. In this patient erosion of the axillary artery produced massive hemorrhage, and emergency transthoracic ligation of the subclavian artery caused gangrene of the extremity and empyema and sepsis. Interscapulothoracic amputation not only was life-saving but offered the patient a reasonable chance for long-term survival. Only aggressive surgical management can salvage a patient with radiation-induced sarcoma

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